Hydrogeological Structure Model of the Olkiluoto Site – Update in

P O S I V A O Y

O l k i l u o t o

F I -27160 EURAJOKI , F INLAND

Te l +358-2-8372 31

Fax +358-2-8372 3809

T i i na Va i t t i nen

Henry Ahokas

Jorma Nummela

Seppo Pau lamäk i

September 2011

Work ing Repor t 2011 -65

Hydrogeological Structure Model ofthe Olkiluoto Site – Update in 2010

September 2011

Working Reports contain information on work in progress

or pending completion.

The conclusions and viewpoints presented in the report

are those of author(s) and do not necessarily

coincide with those of Posiva.

T i i na Va i t t i nen

Henry Ahokas

Jorma Nummela

Pöyry F in l and Oy

Seppo Pau lamäk i

Geo log ica l Su rvey o f F in l and

Work ing Report 2011 -65

Hydrogeological Structure Model ofthe Olkiluoto Site – Update in 2010

Base maps: ©National Land Survey, permission 41/MML/11

HYDROGEOLOGICAL STRUCTURE MODEL OF THE OLKILUOTO SITE – UPDATE IN 2010 ABSTRACT As part of the programme for the final disposal of spent nuclear fuel, a hydrogeological structure model containing the hydraulically significant zones on Olkiluoto Island has been compiled. The structure model describes the deterministic site scale zones that dominate the groundwater flow.

The main objective of the study is to provide the geometry and the hydrogeological properties related to the groundwater flow for the zones and the sparsely fractured bedrock to be used in the numerical modelling of groundwater flow and geochemical transport and thereby in the safety assessment. Also, these zones should be taken into account in the repository layout and in the construction of the disposal facility and they have a long-term impact on the evolution of the site and the safety of the disposal repository.

The previous hydrogeological model was compiled in 2008 and this updated version is based on data available at the end of May 2010. The updating was based on new hydrogeological observations and a systematic approach covering all drillholes to assess measured fracture transmissivities typical of the site-scale hydrogeological zones. New data consisted of head observations and interpreted pressure and flow responses caused by field activities. Essential background data for the modelling included the ductile deformation model and the site scale brittle deformation zones modelled in the geological model version 2.0. The GSM combine both geological and geophysical investigation data on the site.

As a result of the modelling campaign, hydrogeological zones HZ001, HZ008, HZ19A, HZ19B, HZ19C, HZ20A, HZ20B, HZ21, HZ21B, HZ039, HZ099, OL-BFZ100, and HZ146 were included in the structure model. Compared with the previous model, zone HZ004 was replaced with zone HZ146 and zone HZ039 was introduced for the first time. Alternative zone HZ21B was included in the basic model. For the modelled zones, both the zone intersections, describing the fractures with dominating groundwater flow, and transmissivity depth ranges, describing hydrogeological influence zones, are provided. To characterise the hydrogeological properties of the bedrock, hydraulic connections interpreted as local-scale features are reported, as well.

The hydrogeological properties of the zones and the bedrock were parameterised for numerical flow simulation purposes. The drillhole-specific and the geometric means of the measured transmissivities were both proposed for use for the zones and the hydraulic conductivity for the bedrock as a function of depth was assessed. The new approach to apply transmissivity depth ranges caused minor changes in the zone transmissivities.

Keywords: Hydrology, transmissivity, hydraulic conductivity, hydrogeological zone, groundwater flow, disposal of spent nuclear fuel.

OLKILUODON HYDROGEOLOGISEN RAKENNEMALLIN PÄIVITYS VUONNA 2010 TIIVISTELMÄ Osana käytetyn ydinpolttoaineen loppusijoitustutkimuksia Olkiluodon saaren alueelle laadittiin tärkeimmät hydrogeologiset vyöhykkeet sisältävä rakennemalli. Rakenne-malli kuvaa deterministisesti pohjavedenvirtausta dominoivat paikkamittakaavan vyöhykkeet.

Tutkimuksen päätavoite oli tuottaa vyöhykkeiden geometria ja hydrogeologiset omi-naisuudet sekä vyöhykkeille että vyöhykkeiden ulkopuolelle jäävälle kallioperälle käy-tettäväksi pohjaveden virtauksen ja geokemiallisen kulkeutumisen numeerisessa mallin-nuksessa ja edelleen turvallisuustarkasteluissa. Nämä vyöhykkeet tulisi ottaa huomioon myös loppusijoitustilojen suunnittelussa ja rakentamisessa ja niillä on pitkäaikais-vaikutuksia alueen evoluutioon ja loppusijoitustilojen turvallisuuteen.

Edellinen hydrogeologinen rakennemalli laadittiin vuonna 2008, tämä päivitys perustuu tutkimusaineistoon, joka oli käytettävissä toukokuun 2010 lopussa. Päivityksessä käytettiin uusia hydrogeologisia havaintoja sekä arvioitiin systemaattisesti kaikkien reikien osalta paikkamittakaavan hydrogeologisille vyöhykkeille tyypilliset transmis-siviteettiarvot. Uudet havainnot koostuivat pohjaveden painekorkeuden monitorointi-aineistosta ja kenttätapahtumien aiheuttamien paine- ja virtausvasteiden tulkinnoista. Olennaisen tausta-aineiston mallinnukselle muodosti duktiilin deformaation malli sekä hauraan deformaation paikkamittakaavan vyöhykkeet, jotka oli mallinnettu geologisen mallin versiossa 2.0. Nämä vyöhykkeet perustuvat sekä geologiseen että geofysi-kaaliseen tutkimusaineistoon.

Mallinnustyön tuloksena hydrogeologinen rakennemalli koostui seuraavista vyöhyk-keistä: HZ001, HZ008, HZ19A, HZ19B, HZ19C, HZ20A, HZ20B, HZ21, HZ21B, HZ039, HZ099, OL-BFZ100 ja HZ146. Edelliseen versioon verrattuna vyöhyke HZ004 korvattiin vyöhykkeellä HZ146 ja esiteltiin uusi vyöhyke HZ039. Vaihtoehtoinen vyöhyke HZ21B luokiteltiin peruskokoonpanoon kuuluvaksi. Mallinnetuille vyöhyk-keille määriteltiin sekä vyöhykelävistys, joka sisältää vedenjohtavuuden kannalta domi-noivat raot, että vyöhykkeen transmissiviteettilävistys, joka kuvaa hydrogeologisen vaikutusalueen. Kallioperän hydrogeologisten ominaisuuksien kuvaamiseksi myös paikallisiksi piirteiksi tulkitut hydrauliset yhteydet raportoitiin.

Vyöhykkeiden ja vyöhykkeiden ulkopuolisen kallioperän hydrogeologiset ominaisuudet parametrisoitiin numeerisia virtaussimulointeja varten. Vyöhykkeille esitettiin mitat-tujen transmissiviteettien reikäkohtaiset arvot sekä geometriset keskiarvot ja kallioperän vedenjohtavuus arvioitiin syvyyden funktiona. Vyöhykkeiden transmissiviteettilävistys-ten käyttöönotto uutena käytäntönä aiheutti vähäisiä muutoksia vyöhykkeiden trans-missiviteetteihin.

Avainsanat: Hydrologia, transmissiviteetti, vedenjohtavuus, hydrogeologinen vyöhyke, pohjaveden virtaus, käytetyn polttoaineen loppusijoitus.

PREFACE

This Report is part of the programme for the final disposal of spent nuclear fuel on Olkiluoto Island. The main objective of the study is to compile a hydrogeological structure model for numerical groundwater flow modelling.

This study has been carried out by Tiina Vaittinen, Henry Ahokas, and Jorma Nummela from Pöyry Finland Oy and Seppo Paulamäki from the Geological Survey of Finland. Tiina Vaittinen has compiled the geometry for the zones and edited the Report, Henry Ahokas has carried out the parameterisation of hydrogeological properties, and Jorma Nummela has generated the 3D model and the related visualisations. Seppo Paulamäki has written Chapters 3.1.1, 3.1.2, and 4.1 related to the geological model and Chapter “Corresponding brittle fault zone” for each hydrogeological zone. He has also performed the fracture analysis for the hydrogeological zones (Chapter 5.10). Turo Ahokas from Pöyry Finland Oy has provided advice regarding geophysics and Joonas Klockars from Pöyry Finland Oy has assisted with WellCAD visualisations. Eeva Käpyaho and Pauliina Aalto have been the contact persons at Posiva Oy.

The Report has been reviewed by Lasse Koskinen, Posiva Oy, Eeva Käpyaho Golder Associates Oy, and Heikki Hinkkanen, Pöyry Finland Oy. The authors wish to thank the reviewers for their valuable comments and suggestions for the Report. Tiina Hiljanen from HI Tekniikan Käännökset Oy is thanked for proofreading the English text.

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TABLE OF CONTENT ABSTRACT TIIVISTELMÄ PREFACE

1 INTRODUCTION ................................................................................................. 5 1.1 Background .................................................................................................. 5 1.2 Report objectives and relations to previous reports ..................................... 5 1.3 Structure of this Report ................................................................................ 8

2 MODELLING APPROACH................................................................................... 9 2.1 Overview ...................................................................................................... 9 2.2 Previous hydrogeological modelling of the site .......................................... 10 2.3 General principles of modelling .................................................................. 12

2.3.1 Geological basis ............................................................................. 12 2.3.2 Hydrogeological basis .................................................................... 14

2.4 Compilation of site-scale structure model .................................................. 15 2.4.1 Analysis of transmissivity values .................................................... 16 2.4.2 Geometry of zones ......................................................................... 18 2.4.3 Transmissivity of zones and hydraulic conductivity of bedrock ...... 21 2.4.4 Uncertainty analysis and alternative geometries ........................... 21

3 DATA SOURCES AND ASSESSMENT OF DATA ............................................ 23 3.1 Geological data .......................................................................................... 23

3.1.1 Ductile deformation data ................................................................ 23 3.1.2 Brittle deformation data .................................................................. 23 3.1.3 Other geological information .......................................................... 25

3.2 Hydrogeological data ................................................................................. 25 3.2.1 Fracture transmissivities ................................................................ 27 3.2.2 Groundwater table and head ......................................................... 30 3.2.3 Hydrogeology of new drillholes ...................................................... 34 3.2.4 Assessment of transmissivity values ............................................. 36 3.2.5 Analysis of flow conditions ............................................................. 39 3.2.6 Analysis of head observations ....................................................... 40

3.3 Geophysical data ....................................................................................... 44

4 HYDROGEOLOGICAL CHARACTERISATION OF THE SITE ......................... 49 4.1 Geological background .............................................................................. 49 4.2 Hydrogeological concept ............................................................................ 56

5 DESCRIPTION OF HYDROGEOLOGICAL SITE-SCALE STRUCTURES ....... 61 5.1 HZ19 system .............................................................................................. 63 5.2 Modelling of HZ19 zones ........................................................................... 66

5.2.1 Background .................................................................................... 66 5.2.2 Modelling data and interpretation ................................................... 66 5.2.3 HZ19 system boundaries ............................................................... 71 5.2.4 Zone HZ19A ................................................................................... 73 5.2.5 Zone HZ19C .................................................................................. 76 5.2.6 Zone HZ19B ................................................................................... 79 5.2.7 Corresponding brittle fault zones ................................................... 82 5.2.8 Uncertainties .................................................................................. 83

5.3 HZ20 system .............................................................................................. 85 5.4 Modelling of HZ20 zones ........................................................................... 90

5.4.1 Background .................................................................................... 90

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5.4.2 Modelling data and interpretation ................................................... 91 5.4.3 HZ20 system boundaries ............................................................. 104 5.4.4 Zone HZ20A ................................................................................. 107 5.4.5 Zone HZ20B ................................................................................. 110 5.4.6 Corresponding brittle fault zones ................................................. 113 5.4.7 Hydraulic connections to sparsely fractured rock ........................ 114 5.4.8 Uncertainties ................................................................................ 115

5.5 Modelling of HZ21 zones ......................................................................... 117 5.5.1 Background .................................................................................. 118 5.5.2 Modelling data and interpretation ................................................. 119 5.5.3 Zone HZ21 ................................................................................... 125 5.5.4 Zone HZ21B ................................................................................. 127 5.5.5 Zone HZ099 ................................................................................. 129 5.5.6 Zone HZ001 ................................................................................. 131 5.5.7 Corresponding brittle fault zones ................................................. 132

5.6 Modelling of zone HZ146 ......................................................................... 133 5.6.1 Background .................................................................................. 134 5.6.2 Modelling data and interpretation ................................................. 135 5.6.3 Zone HZ146 ................................................................................. 136 5.6.4 Corresponding brittle fault zone ................................................... 138

5.7 Modelling of zone HZ008 ......................................................................... 138 5.7.1 Background .................................................................................. 139 5.7.2 Modelling data and interpretation ................................................. 139 5.7.3 Zone HZ008 ................................................................................. 141

5.8 Modelling of zone HZ039 ......................................................................... 141 5.8.1 Modelling data and interpretation ................................................. 141 5.8.2 Zone HZ039 ................................................................................. 143 5.8.3 Corresponding brittle deformation zones ..................................... 144 5.8.4 Uncertainties ................................................................................ 144

5.9 Zone OL-BFZ100 ..................................................................................... 145 5.9.1 Background .................................................................................. 145 5.9.2 Description of brittle fault zone ..................................................... 145 5.9.3 Hydrogeological properties .......................................................... 146

5.10 Fracture properties and lithology of zones ............................................... 148 5.11 Possible hydrogeological zones ............................................................... 150

5.11.1 Site-scale BFZs ............................................................................ 150 5.11.2 Zone HZ056 ................................................................................. 151

5.12 Bounding lineaments ............................................................................... 157 5.13 Summary and cross-sections of the model .............................................. 157

6 HYDROGEOLOGICAL LOCAL-SCALE STRUCTURES ................................. 165 6.1 Local-scale features ................................................................................. 165 6.2 Single fracture transmissivities ................................................................ 171

7 PARAMETERISATION OF INITIAL HYDRAULIC PROPERTIES FOR NUMERICAL FLOW MODELLING ................................................................... 173

7.1 Transmissivity of zones ............................................................................ 173 7.2 Hydraulic conductivity of bedrock outside deterministic zones ................ 175 7.3 Thickness of zones .................................................................................. 178 7.4 Fracture space and aperture .................................................................... 179

8 UNCERTAINTY ASSESSMENT ...................................................................... 181 8.1.1 Conceptualisation of rock mass ................................................... 181 8.1.2 Observation of hydrogeological parameters ................................ 181

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8.1.3 Interpretation of observations ...................................................... 181 8.1.4 Geometry of the zones ................................................................. 182 8.1.5 Other hydraulic features ............................................................... 182

9 SUMMARY AND DISCUSSION ....................................................................... 183 9.1 Summary .................................................................................................. 183 9.2 Discussion ................................................................................................ 186

REFERENCES ........................................................................................................ 189

APPENDICES .......................................................................................................... 199 Appendix 1. Drillhole logs in drillholes OL-KR1�OL-KR53. ............................. 199

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1 INTRODUCTION

1.1 Background

Posiva Oy is carrying out an investigation programme for the final disposal of spent nuclear fuel on Olkiluoto Island. Site investigations were started in Olkiluoto in 1988 and in 1999 Posiva proposed Olkiluoto as the site for the final disposal facility. In 2000, the Government made a Decision in Principle in favour of the project, and in 2001 the Parliament ratified the Decision in Principle on locating the repository in Olkiluoto.

As part of the site investigations, an underground rock characterisation facility, the ONKALO, has been under construction in Olkiluoto since 2004. The aim of the ONKALO is to study the bedrock of the site for the planning of the repository and for a safety assessment, and to test disposal techniques in real deep-seated conditions.

1.2 Report objectives and relations to previous reports

Groundwater flow characteristics provide essential input for the construction and safety assessment of the disposal facility for spent nuclear fuel. The hydrogeological structure model of the Olkiluoto site describes hydraulically significant zones (HZs) of major importance. Due to the significance of the HZs as possible groundwater flow routes from the repository to the ground surface facilitating transport of potentially released radionuclides, and the risk they introduce to buffer performance, these zones should be taken into account in the repository layout and in the construction of the disposal facility and in assessing their impact on the long-term evolution of the site and the safety of the disposal repository. The model provides geometries and hydrogeological properties related to groundwater flow routes for the zones and the sparsely fractured bedrock to be used in the numerical modelling of groundwater flow and geochemical transport and thereby in the safety assessment.

The description of the hydrogeological characteristics of the bedrock provides local-scale information on the bedrock outside site-scale zones. These properties are needed e.g. in tunnel scale modelling required for the construction of the ONKALO, in layout planning and in the Rock Suitability Criteria project (RSC), as well as in support of groundwater sampling.

The previous hydrogeological structure model was compiled in 2008 and this updated version is based on data available at the end of May 2010. New investigation data have since 2008 been gathered both on the ground surface and underground: five new deep drillholes have been drilled, the excavation of the ONKALO access tunnel has continued to a length of 4 300 m, i.e. it has almost reached the planned repository level at a depth of -420 m, and the raise boring of the personnel shaft and two ventilation shafts has been extended down to -290 m.

As a result of the site modelling work, Geological Site Model of Olkiluoto (GSM) version 2.0 (Aaltonen et al. 2010), ONKALO Area Model version 1.1 (Lahti et al. 2009), and the surface and near-surface hydrological model (Karvonen 2008, 2009) have been published since the 2008 hydrogeological model. In addition, the first versions of statistical-based discrete fracture network (DFN) models (Buoro et al. 2009,

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Hartley et al. 2009) have been introduced for both geological (geoDFN) and hydrogeological (hydroDFN) purposes to complement the deterministic geological and hydrogeological structure models. Co-operation with the geological modelling group (GeoMTF) has been ongoing to establish the best consistent understanding of the Olkiluoto site at the moment. Since the beginning of the site investigations, the matching of hydrogeological features with geological brittle features has been assessed in the modelling campaigns. In 2008, the GeoMTF group introduced the definition of geological background to the conceptual description of the hydrogeological character of the rock mass, based on the interpretation of the tectonic units on Olkiluoto Island. The modelling of the tectonic units and sub-units has proceeded as a part of the structural interpretation of Olkiluoto and is referred to as a ductile deformation model in GSM version 2.0.

The modelling volume is shown in Figure 1-1 and the area with deep drillholes in Figure 1-2. The modelling volume is constrained by regional-scale bounding lineaments (Figure 1-1 ) and the model covers a depth range down to -2 000 m.

Figure 1-1. The modelling volume is constrained by bounding lineaments. The volume reaches down to -2 000 m.

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1.3 Structure of this Report

This Report consists of nine Chapters. Chapter 2 discusses the methodology for the compilation of the hydrogeological structure model and Chapter 3 the investigation data available for modelling at the end of May 2010. In Chapter 4 an assessment of the hydrogeological observations against the geological tectonic units and thereby a fitting to the concept of the geological background is carried out. Chapter 5 provides descriptions of the modelled hydrogeological site-scale zones and connections with the current geological brittle deformation model. Chapter 6 presents the interpreted local features. The parameterisation of the initial values, e.g. the transmissivity of the zones and the hydraulic conductivity of the sparsely fractured rock for numerical groundwater flow modelling purposes is presented in Chapter 7. Uncertainties are considered in Chapter 8, and Chapter 9 includes a summary of the Report and discussion on the model. The Report also contains the history of hydrogeological modelling and the hydrogeological zones as well as uncertainties related to the modelling of the zones. The parameterisation of other hydrogeological parameters used in numerical modelling, e.g. groundwater table and salinity, is not presented in this Report.

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2 MODELLING APPROACH

2.1 Overview

The descriptive Olkiluoto site model consists of separate models in four disciplines: a geological model, a rock mechanical model, a hydrogeological model, and a hydrogeochemical model. The geological model evaluates the geological properties and conditions of the rock mass on the Olkiluoto Site and provides the geometrical framework and geoscientific descriptions for other models, cf. Figure 2-1. The current geological site model, the GSM (Aaltonen et al. 2010), contains a lithological model, a ductile deformation model, an alteration model, a brittle deformation model, and a geoDFN model. The hydrogeological model contains a hydrogeological structure model and a numerical groundwater flow model. Both Equivalent Porous Media (EPM) (e.g. Löfman et al. 2009) and DFN (e.g. Hartley et al. 2011) approaches are applied. This Report presents the hydrogeological description of the site and the compilation of the hydrogeological structure model of the Olkiluoto site. The structure model focuses on site-scale hydrogeological phenomena.

From the hydrogeological site-scale modelling point of view, the bedrock consists of sparsely fractured rock with low fracture transmissivity, and hydrogeological zones with moderate or high fracture transmissivity. The modelling task was carried out in two phases: 1) hydrogeological description of the site and 2) compilation of the site-scale structure model for numerical modelling purposes, cf. Figure 2-2.

Figure 2-1. Flow chart of the interaction between the geological model and other disciplines (Aaltonen et al. 2010).

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Hydrogeological descriptionof the site

Site scale structure model

and parameterisationfor numerical modelling

Construction of ONKALO

Lay-out planning Supportinggroundwater

sampling

Deterministic site-scale flow model Hydro-DFN model


Site scale structure model

and parameterisationfor numerical modelling

Construction of ONKALO

Lay-out planning Supportinggroundwater

sampling

Deterministic site-scale flow model Hydro-DFN model

Figure 2-2. Schematic description of the modelling and end-users.

2.2 Previous hydrogeological modelling of the site

The first bedrock model for the Olkiluoto site was compiled in 1992 as a result of the preliminary site characterisation phase carried out in 1988-1992 (Saksa et al. 1993). Five deep drillholes were available for site investigation in 1992. During the detailed site characterisation phase that started in 1993, the bedrock model was updated in 1996 (Saksa et al. 1996), in 1997 (Saksa et al. 1998), and in 1999 (Anttila et al. 1999). At that time the descriptive bedrock model consisted of a lithological model, a structural model, and a hydrological model. The number of deep drillholes increased from five to 10 in 1999.

During the early stages of site investigations, the hydrological model was a sub-model of the structural model containing hydraulically important fractured zones, i.e. zones containing drillhole sections with high transmissivity. The interpretation of the fractured zones was mainly based on the results of geological and geophysical investigations and most of the zones were either moderately or steeply dipping. The selected hydraulically important zones were simplified to create the geometry for numerical groundwater flow modelling.

Sub-horizontal hydrogeological zones were for the first time studied in numerical groundwater flow modelling as alternative interpretations of the field investigations in 1996 (after Ahokas in Löfman 1996). Sub-horizontal site-scale fractured zone R21 was modelled in the bedrock model in 1997 (Saksa et al. 1997) and site-scale hydrogeological zones R19HY and R20HY were introduced in 1999 (Anttila et al. 1999, Löfman 1999). The interpretations of hydrogeological zones R19HY and R20HY were based on pumping tests carried out in the 1990s.

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During the 2001-2003 period, the bedrock model was updated in 2001 (Vaittinen et al. 2001 and Saksa et al. 2002) and in 2003 (Vaittinen et al. 2003). In addition, updates were carried out in 2002 for two sub-models to study the location for the ONKALO access tunnel (Vaittinen et al. 2004a and 2004b). For the 2003 model, data of 23 deep drillholes were available. In 2001 hydraulic conductivity (K2m) was added as one of the criteria determining structural intersections in drillholes, whereby hydrogeological zones were based on the integrated interpretation of engineering geological criteria and hydraulic conductivity. Based on the properties of the drillhole intersections, the modelled zones were classified to belong either to a structural model, to a hydrological model, or to both models. The orientation and continuity of the zones were determined using the results of hydraulic interference tests, geophysical measurements, fracture orientation, and planarity assumption. For each modelled zone, a certainty value related to the orientation and continuity of the zones was given (Vaittinen et al. 2003).

Modelling was divided into separate disciplines after bedrock model version 2003/1, which is why engineering geological criteria have not been applied to hydrogeological modelling since. However, although zone R21 was strongly based on engineering geological criteria, it was kept in the hydrogeological model due to its intensive fracturing and its possible role as a major route for deep saline groundwater as well as for radionuclides from repository level to the biosphere (Ahokas et al. 2007).

A brief update for hydrogeological zones was performed for the estimation of leakage water inflow into the ONKALO (Sievänen et al. 2006) and a more extensive update for assessing grouting after the penetration of the HZ19 zones (Ahokas et al. 2006). A thorough hydrogeological model upgrade, aimed at numerical groundwater flow modelling and lay-out planning, was compiled in 2006 (Ahokas et al. 2007).

The 2006 model (Ahokas et al. 2007) described site-scale hydrogeological features, where high transmissivities are common and hydraulic connections between drillholes were observed as pressure and flow responses during the pumping tests performed and other field activities. All drillhole intersections with a transmissivity higher than 1·10-5 m2/s below approximately -150 m.a.s.l. were considered, but due to the known heterogeneity of hydraulic properties within hydrogeological zones, no specific minimum limit value for transmissivity in the drillholes was determined to imply the occurrence of a zone. The continuity of the zones was mostly based on hydraulic connections interpreted from observed hydraulic responses with geophysical measurements supporting continuity. In addition, the geometry of the zones and fitting fracture transmissivities were taken into account. One of the zones was based on anomalous low heads observed in the drillholes. Altogether 39 deep drillholes were available for the modelling work.

The 2008 version was mainly compiled according to the same modelling concept as the 2006 version. However, in 2006 the HZs were modelled to describe site-scale hydrogeological phenomena and the geometry of the zones was not exactly fixed on the basis of drillhole observations. To meet requirements related to e.g. the geological characterisation of the hydrogeological zones and adjusting groundwater sampling, some of the zones were changed to coincide more accurately with drillhole observations. In addition, the nature of the HZs in Olkiluoto, the restricted extent and short intersections in the drillholes, with only one highly transmissive fracture in places,

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necessitated slightly changed drillhole descriptions for the zones. Data on 48 deep drillholes were applied in the modelling work. A hypothesis of the effect of tectonic units on the hydrogeological properties of the bedrock was introduced.

2.3 General principles of modelling

Until 2003, the hydrogeological observations were combined with engineering geological and geophysical investigation data in the bedrock model. Since the start of discipline-specific modelling, the compilation of the hydrogeological model has mainly been based on new hydrogeological observations: fracture transmissivity and head as single-hole observations, and the results of interference tests as well as the flow and pressure responses to field activities as cross-hole observations. All site-scale BFZs are assessed for numerical modelling purposes, and are taken into account either in the basic model or in the uncertainty assessment. Schematic descriptions of the processes for 1) hydrogeological description of the site and 2) compilation of the site-scale structure model for numerical modelling purposes are given in Figure 2-3 and Figure 2-5, respectively.

2.3.1 Geological basis

The geological model of the Olkiluoto site, the GSM, was updated to version 2.0 in 2010 (Aaltonen et al. 2010). The models of ductile deformation and brittle deformation are of the essence as background information for hydrogeological modelling.

The ductile deformation model is applied to provide the geological background for the hydrogeological conceptualisation of the rock mass (Vaittinen et al. 2009b). The interpretation of the structural features described in the ductile model has been continued and a more detailed map and a 3D model are presented in GSM version 2.0.

The reactivation of the ductile and semi-ductile deformation structures within the later brittle deformation may have produced open channels for groundwater flow. The brittle deformation model therefore describes possible hydrogeological features. In the brittle deformation model, modelled BFZs are classified into two categories based on their lateral extent: site-scale zones and repository-scale zones. The zone is classified as a site-scale zone, if its lateral dimension at any depth and in any direction is 1 000 m or greater. Its extent is defined by several drillhole intersections and/or geophysical or topographic data. The other zones with a lateral extent of less than 1 000 m are systematically classified as repository-scale zones, which are usually based on one or at most only a few drillhole intersections, their orientation being mainly based on the orientation of the slickenside fractures in the inferred core zones. Their actual extents are often highly uncertain. The current brittle deformation model version 2.0 (Aaltonen et al. 2010) includes 178 modelled fault zones, of which 22 are classified as site-scale zones.

When the hydrogeological structure model is considered against the brittle deformation model, a notable observation is that the site-scale BFZs with continuity between the drillholes based on geophysical measurements coincide with the hydrological cross-hole connections.

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Fracture T � limit value as a function of depth


Hydraulicconnections

Single-holeobservations

Cross-holeobservations

Geologicalmodel v 2.0

Site-scale BFZ

Integrated analysis- hydrogeological properties of features

Classification based on- transmissivity

- hydraulic / geophysical continuity- size

Site-scale features- hydrogeological zones

Local-scale features- single-hole features

- local hydrogeological zones

Alternative interpretations- possible hydrogeological zones

Modelling & parameterisationof zones for numerical

purposesVisualisation of features

Drillhole intersections

Fracture T � limit value as a function of depth


Hydraulicconnections

Single-holeobservations

Cross-holeobservations

Geologicalmodel v 2.0

Site-scale BFZ

Integrated analysis- hydrogeological properties of features

Classification based on- transmissivity

- hydraulic / geophysical continuity- size

Site-scale features- hydrogeological zones

Local-scale features- single-hole features

- local hydrogeological zones

Alternative interpretations- possible hydrogeological zones

Modelling & parameterisationof zones for numerical

purposesVisualisation of features


Figure 2-3. Schematic description of the approach applied to hydrogeological description of the site.

It is typical of these site-scale BFZs that in addition to increased fracturing, the features are characterised by electrical conductors. Due to the physical properties of electrical conductors, geophysical cross-hole and 3D investigation methods are well suited for studying the continuity of these zones. However, high fracture transmissivities and the observed hydrological connections only cover these site-scale BFZs partly, probably due to internal hydrological heterogeneity caused by the structure of BFZs, which may either enhance or impede groundwater flow. This is discussed more in Chapter 4. Short

14

Sparsely fractured rock

Hydrogeological zone

Sparsely fractured rock

Hydrogeological zone

descriptions of BFZs (Aaltonen et al. 2010) corresponding to modelled HZs are given in Chapter 5.

2.3.2 Hydrogeological basis

The modelling of the HZs is based on the concept of the hydraulic character of the crystalline bedrock. The rock mass is assessed to be strongly channelled, i.e., the major portion of groundwater flows along hydrogeologically essential deformation zones and only a minor portion along fractures within sparsely fractured rock between HZs (cf. Figure 2-4).

The update of the site-scale hydrogeological structure model mostly follows the approach applied in the previous 2008 version. However, to consider more comprehensively the observed transmissivities, which are typical to HZs, a systematic approach covering all the drillholes was used. Because the hydraulic conductivity of the bedrock is strongly dependent on depth, limit transmissivity values were determined as a function of depth to find out anomalous drillhole sections. The limit values were applied systematically to detect anomalous fractures and depending on the interpretation, the fractures were included in either HZ or sparsely fractured rock (cf. Chapter 2.4.1).

As in the previous version of the hydrogeological model, the focus is on high and moderate fracture transmissivities, but no minimum limit value is applied when the continuity of a zone is interpreted. The continuity of the zones is mostly based on hydraulic responses observed during pumping tests, overpressure tests, and various field activities. It is known that there is a risk that pressure responses may be obscured by the effects of open drillholes or the nearby ground surface, and that packed-off sections do not cover all the transmissive fractures. However, the intention is to provide a structure model of an as high internal consistency as possible based on interpreted observations. All uncertainties related to the interpretation of pressure responses are reported.

Figure 2-4. Conceptual visualisation of the hydrogeological zone and sparsely fractured rock.

15

For the hydrogeological description of the site, drillhole intersections based on anomalous transmissivity, interpreted hydraulic connections, and site-scale BFZ were analysed together, and the continuity and hydraulic properties of the features were determined, cf. Figure 2-3. The interpreted features were classified to belong to either site-scale or local-scale features on the basis of transmissivity, whether continuity is based on hydraulic or geophysical measurements, and the size of the feature. Site-scale features were modelled as 3D HZs, cf. Chapter 2.4.

2.4 Compilation of site-scale structure model

A schematic description of the approach applied in the modelling and parameterisation of the HZs and sparsely fractured rock for numerical modelling purposes is given in Figure 2-5. When modelling geometry for the HZs, the use of the structure model in site-scale numerical EPM groundwater flow modelling and statistical DFN modelling is taken into account, i.e. hydraulic connectivity is needed, and the volume between drillholes and the model boundaries should have hydrogeological characterisation in numerical flow modelling. When the length of a zone intersection is determined, the main issue is that all substantial transmissive fractures are included in a zone.

16

Drillhole intersections (DFN modelling, lay-out planning)

- 3D solid - Transmissivity range

Site-scale structure model &

parameterisationfor numerical purposes

Hydrogeological zones

- Possible hydrogeologicalzones

-Alternative geometriesof zones

Geometry(hydraulic connectivity)

Transmissivity(heterogeneous / geometric mean)

Sparsely fracturedrock

- Biased observation of hydrogeological properties

Hydraulic conductivityas a function of depth

Uncertaintyassessment












































Figure 2-5. Schematic description of the approach applied in compiling the site-scale hydrogeological structure model. Main issues to take into account are shown in parenthesis.

2.4.1 Analysis of transmissivity values

A systematic approach comprising all deep drillholes up to OL-KR53, the available B-drillholes, and pilot holes up to ONK-PH13 was used. Due to the strongly depth-dependent hydraulic conductivity of the bedrock, limit transmissivity values decreasing

17

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.E-10 1.E-09 1.E-08 1.E-07 1.E-06 1.E-05 1.E-04 1.E-03

T, m2/s

Cum

ulat

ive

frequ

ency

Depth range above -50m Anomalous T Depth range -50 - -350mAnomalous T Depth range below -350 m Anomalous T

with depth were determined. Following the concept of strongly channelled groundwater flow, it was estimated that approximately only one tenth of groundwater flow occurs within sparsely fractured rock and the rest within the zones, cf. Figure 2-6.

Based on the distribution of the transmissivity values (Figure 2-6), depth ranges above -50 m.a.s.l., between -50 and -350 m.a.s.l., and below -350 m.a.s.l. were assessed as reasonable for the application of limit transmissivity values. For all fractures with transmissivity higher than the limit value below -50 m, it was assessed if they belong to a site-scale zone or to sparsely fractured rock. For the topmost depth range most of the high transmissivities are assessed to be related to general fracturing occurring close to the bedrock surface instead of site-scale features. The determined depth ranges and the corresponding limit transmissivity values for anomalous fractures are shown in Table 2-1. The results of the analysis are given in Chapter �.

Table 2-1. Determined depth ranges and corresponding limit transmissivity values for detection of anomalous fracture-specific transmissivities.

Depth range m.a.s.l.

Anomalous fracture transmissivityT, m2/s

above -50 1·10-6 -50 - -350 2·10-6 below -350 3·10-7

Figure 2-6. Fracture transmissivity (T) values and anomalous T-values illustrated with darker colour within each depth range. The sum of anomalous T-values represents approximated amount of the groundwater taking place within the zones.

18

2.4.2 Geometry of zones

Following the modelling of fault zones in the geological brittle deformation model (Aaltonen et al. 2010), the basic idea of the modelling procedure is that hydrogeological zones are planar/semiplanar features. In many cases their continuity is difficult to estimate, but the central area is rather densely drilled, so the surrounding drillholes largely control the extent of the features.


The main issue when determining the length of a zone intersection is that all substantial transmissive fractures are included in the zone, i.e. transmissive fractures characterising hydrogeological site-scale zones and those characterising averagely fractured rock are classified. Two kinds of drillhole intersections have been determined for the hydrogeological zones:

1. zone intersection and2. transmissivity depth range.

Examples of the determined zone intersections and transmissivity depth ranges are presented in Figure 2-7.

Zone intersection Zone intersections are used to model 3D objects for the description of geological properties and for visualisation purposes and they contain the highest fracture transmissivities attached to a zone.

Following the 2008 version, the criteria defined in bedrock model version 2003/1 (Vaittinen et al. 2003) were essentially applied to the HZ zone intersections (cf. Appendix 1: column 2003/1). The criteria are based on the concept that HZs generally occur in drillhole sections with increased fracturing and fracturing characterises the zone intersection. The primary criterion is that at least 10 fractures/m over a 2 m borehole length were mapped in the fracture log presented in the original drilling report. The intersection boundaries are set at the depths where the fracture frequency is less than 7 fractures/m over a 2 m borehole length. The secondary criterion is the depth of the anomalous transmissive fracture ± 1 m.

Transmissivity depth range In many cases transmissive fractures occur such a way that fractures with somewhat lower transmissivity are in the vicinity of the highest fracture transmissivities (Hellä et al. 2006, Hellä et al. 2009) and presumably they are connected to each other, i.e., they characterise the hydrogeological influence zone. Therefore zone intersections are extended by transmissivity depth range. Transmissivity depth ranges determine drillhole sections excluded from the averagely fractured rock (cf. Appendix 1: column HZ 2010).

For the transmissivity depth ranges three different defining methods were used in prioritised order:

19

� drillhole-specific geological influence zone determined for selected site-scale BFZs (OL-BFZ019C, -BFZ020A, -BFZ020B, -BFZ021, and -BFZ099),

� zone-specific hydrogeological influence zone determined for selected HZs (HZ20A, HZ20B, HZ21, HZ21B, and HZ099), and

� drillhole-specific hydrogeological influence zone determined for zone intersections not defined by above-mentioned methods.

Drillhole-specific geological influence zones (cf. Appendix 1: column BFM 2.0) are available for zones OL-BFZ019C, -BFZ020A, -BFZ020B, -BFZ021, and -BFZ099. Influence zones are described in the GSM versions 1.0 and 2.0 (Mattila et al. 2008, Aaltonen et al. 2010) related to the modelling campaigns and in Hellä et al. (2009) describing definitions for the Layout Determining Features (LDF). The criteria applied to select LDFs were under development and in addition to geological, hydrogeological, and rock mechanics properties, expert judgement and geoscientific knowledge of the site were taken into account.

According to model 2008, zone-specific hydrogeological influence zones have been determined for hydrogeological LDF zones HZ20A, HZ20B, HZ21, HZ21B, and HZ099 in Hellä et al. (2009). For the HZ20 zones determined maximum value 15 m has been applied above HZ20A and below HZ20B. For zones HZ21 and HZ21B determined maximum value 20 m has been used above and below the zone and for zone HZ099 value 10 m, respectively.

If neither drillhole-specific geological nor zone-specific hydrogeological influence zone is available, a drillhole-specific hydrogeological influence zone determined for highly transmissive fractures in Hellä et al. (2009) was applied. To determine the influence zone a 10 m drillhole section both upwards and downwards from drillhole intersection was checked for transmissivity values one order of magnitude lower than the limit values for anomalous fractures in corresponding depth ranges (cf. Table 2-1). If such fracture was found, the transmissivity depth range was set 1 m apart from that fracture.

The examples in Figure 2-7 show three cases. The transmissivity depth range is determined according to the geological influence zone in drillhole OL-KR22. In drillhole OL-KR25 the transmissivity depth range follows the zone-specific hydrogeological influence zone and in drillhole OL-KR8 the drillhole-specific hydrogeological influence zone value has been applied to determine the transmissivity depth range.

20

OL-KR22 OL-KR25 OL-KR8OL-KR22 OL-KR25 OL-KR8

Figure 2-7. Examples of the determined zone intersections and transmissivity depth ranges. Columns from left to right: 2003/1 intersections, BFZs with influence zones, HZs with transmissivity depth ranges, and PFL fracture transmissivities (red circles) and HTU if available (blue line). Transmissivity depth ranges based on BFZ influence zone in drillholes OL-KR22, on zone-specific in -KR25, and on drillhole-specific hydrogeological influence zone in -KR8 (cf. Appendix 1 for legend information).

3D visualisation of zones

The zones are modelled as triangular nets without smoothing. The upper and lower surfaces follow the defined drillhole zone intersections. Surrounding drillholes control the extent of the zones in the central area. The extrapolation of the zones outside the central area covered by deep drillholes is based on expert judgement. The calculation of the extrapolated corner coordinates is based on the intersections of nearby drillholes. Linked lineaments (Korhonen et al. 2005) are used to illustrate the boundary geometry

21

for the zones (cf. Chapter 3.1.3). Most of the zones are assessed to have a limited extent so extrapolation covers relatively small areas. If there are no indications of a restricted size for the zone, such zones are extended to intersect the bounding lineaments. The depth range of the model is -2 000 m.

Lay-out determining features

Defined transmissivity depth ranges are also applied to model the LDFs. Hydrogeological zones HZ20A, HZ20B, HZ21, HZ21B, HZ039, HZ099, and HZ146 intersecting the planned repository depth are defined as LDFs in the current model. Drillhole-specific transmissivity depth ranges and the applied defining method are given in Chapter 5.

2.4.3 Transmissivity of zones and hydraulic conductivity of bedrock

The updating of drillhole and zone-specific transmissivities was guided by the determination of zone intersections and transmissivity depth ranges described in the previous Sections. The sum of the fracture specific transmissivities measured mainly by the Posiva flow log (PFL-tool) was used for each drillhole intersection. For very highly transmissive drillhole sections, the results of the pumping tests were also used due to uncertainties related to the determination of a high flow rate with the PFL-tool.

Transmissivities outside the determined transmissivity depth ranges of the zones were used as a database for the analysis of the hydraulic conductivity of the averagely fractured bedrock.

2.4.4 Uncertainty analysis and alternative geometries

Uncertainties related to the interpretation of the geometry of the hydrogeological zones are assessed in Chapter 5. All site scale BFZs are parameterised for numerical EPM modelling purposes to be taken into account as possible hydrogeological zones to assess uncertainties related to the structure model (cf. Chapter 7).

22

23

3 DATA SOURCES AND ASSESSMENT OF DATA

The modelling of the hydrogeological zones is mainly based on hydrogeological investigation data, but essential background data include the ductile deformation model and site-scale BFZs modelled in GSM version 2.0 (Aaltonen et al. 2010). Site-scale BFZs combine both geological and geophysical investigation data on the site.

3.1 Geological data

Geological properties describing hydraulically important features are characterised in the ductile deformation model and in the brittle deformation model (Aaltonen et al. 2010).

3.1.1 Ductile deformation data

The two-dimensional ductile deformation model is based on the results of surface mapping (outcrops, investigation trenches and upper sections of drillholes) and available surface and airborne geophysical, especially magnetic survey, information. Relicts of lithological layering and a weak foliation of the first phase of deformation (D1) represent the oldest observed structural elements (Aaltonen et al. 2010). The second phase (D2) caused intense folding and ductile shearing simultaneously with strong migmatitisation. During the third deformation phase (D3), the deformed migmatites were re-folded and sheared and subareas dominated by D3 structural elements were formed. Simultaneously, pegmatite-like dykes or migrated leucosomes intruded commonly parallel to the D3 shear bands and axial surfaces. Subsequently, all earlier structural elements were re-deformed during the fourth deformation phase (D4), which produced close to open folds and ductile shear structures.

The three-dimensional ductile deformation model attempts to visualise the geometry of structural symmetry and the most intensely deformed ductile zones on the Olkiluoto site. After the reconstruction of the structural interpretation based on surface and subsurface mapping, the orientation of the pervasive foliation, determined from the surface and the drillholes, was applied in the extrapolation of the 2D structural reconstruction into 3D. The main units are described in Chapter 4.1 and a detailed description of the ductile model is given in Aaltonen et al. (2010).

3.1.2 Brittle deformation data

The site-scale BFZs, based on data mainly from drillholes, consist of a core zone and upper and lower influence zones on either side of the core. Cores correspond to the most deformed part of the deformation zone intersection in the drillhole or the ONKALO access tunnel, where there is a clear increase in the fracture frequency and/or increase in the number of slickensides, occurrence of brecciated and/or crushed rock, gouge material, clay fillings etc. In addition, the minimum in the P-wave velocity can be used in the definition of the core boundaries. For the influence zones, a set of rules has been applied, e.g. increased fracture frequency, both pervasive and fracture-controlled hydrothermal alteration, geophysical anomalies indicating poor rock quality, and hydraulic conductivity have been taken into account. A detailed description of the

24

definition of the site-scale BFZs is given in Aaltonen et al. (2010). They are visualised in Figure 3-1.

The orientation and extent of the site-scale BFZs is based on a combination of one or all of the following geophysical and geological methods: Mise-à-la-masse measurements, Vertical Seismic Profiling, 3D seismic and HIRE reflectors, electromagnetic Gefinex 400 soundings, fault plane orientations, geologically meaningful geometry, microseismic events, and lineaments if supported by other data (Aaltonen et al. 2010).

In addition to increased fracturing, the site-scale BFZs are typically characterised by electrical conductors. Due to the physical properties of the conductors the aforementioned geophysical measurements are suited for studying the continuity of these zones.

HZs cannot straightforwardly be based on BFZs, because in some drillhole sections without geological evidence of a brittle deformation zone, the transmissivity of a distinct fracture may be in the order of 1·10-5 m2/s. On the other hand, more than 60 000 core mapped fractures have been gathered in the fracture database (Aaltonen et al. 2010) while the number of transmissive fractures is about 4 800 (Tammisto et al. 2009, Palmén et al. 2010, and Tammisto & Palmén 2010).

Figure 3-1. All modelled site-scale BFZs in version 2.0 (Aaltonen et al. 2010), green colour refers to high-confidence zones, red to medium-confidence zones, and yellow to low-confidence zones, view towards northwest.

25

3.1.3 Other geological information

To provide information on the geological properties of the rock mass at the site, the following geological drill core mapping data are visualised in Appendix 1: lithology, fracture frequency and core loss sections, all oriented fractures and orientation of transmissive fractures in terms of dip direction and dip, and fracture intensity based on Finnish engineering geological classification (Korhonen et al. 1974).

Because the modelling of the hydrogeological zones is based on drillhole observations and the zones have not been identified on the ground surface, the geometry of the zone boundaries cannot be approximated. Following the practice of the previous 2008 model, interpreted linked lineaments (Korhonen et al. 2005) are used to estimate the boundary geometry for the zones following the dominant trends of the geological features. The intention is to create a visually consistent hydrogeological structure model with the geological trends. The linked lineaments are based on integrated interpretation of geophysical (magnetic, electromagnetic, seismic, and marine) and topographic lineaments. The linked lineaments are shown on the map of Olkiluoto Island in Figure 3-2.

Figure 3-2. Ground surface map of interpreted linked lineaments on Olkiluoto Island (Korhonen et al. 2005) and ONKALO with varying colours. Bounding lineaments are shown as thick lines.

3.2 Hydrogeological data

Modelling was divided into separate disciplines after bedrock model version 2003/1 and since then the compilation of the hydrogeological structure model has mainly been based on new hydrogeological observations: fracture transmissivity and head as single-

26

hole observations, and the results of interference tests as well as the flow and pressure responses to field activities as cross-hole observations, cf. Table 3-1.

Table 3-1. Hydrogeological measurements applied to interpretation of hydrogeological zones, PFL refers to Posiva Flow Log -tool and HTU to Hydraulic Testing Unit -tool.

Observation Applied to Factors causing uncertainties in interpretation

Single-hole observations, PFL

- fracture transmissivity T, m2/s

- zone intersections - transmissivity of zones - hydraulic conductivity of the rock outside zones

- field activities in nearby drillholes - unmeasured drillhole sections due to intensively fractured rock

- head H, m - head distribution - zone(s) of anomalous heads (- hydraulic connections between drillholes)

- field activities in nearby drillholes - seasonal effects - error in z-coordinate of a drillhole

- flow Q, ml/h - interpret flow responses - field activities in nearby drillholes - seasonal effects

Single-hole observations, HTU

- hydraulic conductivity K2m, m/s

- transmissivity of zones - hydraulic conductivity of the rock outside zones

- representativeness of results due to flow field outside a test section (short circuits back to drillhole)

Monitoring of head - head H, m - interpret baseline heads

(anomalous heads) - interpret head variation (pressure responses)

packed-off drillholes - density differences in measuring hoses - leakages in measuring hoses open drillholes - responses may be masked by other zones - observation only once a week (manual measurements)

Cross-hole observations

- flow responses during interference tests and caused by field investigations - pressure responses during interference tests and caused by field investigations

- hydraulic connections between drillholes

- open drillholes spread pressure effects - effects from pumped/overpressure section to open part of drillhole - pressure response may be masked and cannot be detected due to high local transmissivity within or near an observation section - field activities in nearby drillholes - leakages in measuring hoses - lack of transverse flow measurements, i.e. flow response cannot be detected by DIFF-tool but might be seen by TRANS-tool - saline effects in pumping hole

27

In order to provide information on the hydrogeological properties of the rock mass at the site, the following measurements are visualised in Appendix 1: flow into a drillhole during flow logging with pumping, fracture transmissivity and transmissivity of 2 m sections by HTU, orientation of transmissive fractures, and flow and flow direction into or out of a drillhole during flow logging without pumping. In addition, the cemented drillhole sections are shown.

3.2.1 Fracture transmissivities

Fracture transmissivities have been measured systematically by means of the PFL-tool in each of the deep drillholes (Pöllänen & Rouhiainen 1996a, 1996b, 2000, 2001, 2002a, 2002b, 2002c, 2002d, 2002e, 2005, Rouhiainen 2000, Rouhiainen & Pöllänen 2003, Pöllänen et al. 2005a, 2005b, Pöllänen 2006, Väisäsvaara & Pöllänen 2007, Sokolnicki & Pöllänen 2008, Pöllänen & Väisäsvaara 2008, Väisäsvaara 2010, and Pekkanen et al. 2010). The drillhole sections measured with the PFL-tool are shown in Figure 3-3. Fracture transmissivities are visualised as oriented discs in Figure 3-4. In order to improve visualisation, only transmissivities higher than 1·10-8 m2/s are shown. The orientation of transmissive fractures in drillholes OL-KR1 � -KR53 is based on Tammisto et al. 2009, Palmén et al. 2010, and Tammisto & Palmén 2010. Most of the transmissive fractures could be fixed with drill core fractures and therefore have an orientation; fractures without a defined orientation are shown as horizontal squares. For drillhole OL-KR39 and extended parts of drillholes OL-KR23 and -KR31, all fractures are unoriented.

Measurements have been carried out in selected drillhole sections using the Hydraulic Testing Unit (HTU-tool, conventional constant head double packer test) with a two-metre packer section. HTU measurements have focused on the planned repository depth range (Hämäläinen 2009).

28

Fig

ure

3-3.

Dri

llhol

e se

ctio

ns m

easu

red

with

PFL

-tool

.

29

T, m

²/s>1

E-8

>1E

-7>1

E-6

>1E

-5

T, m

²/s>1

E-8

>1E

-7>1

E-6

>1E

-5

T, m

²/s>1

E-8

>1E

-7>1

E-6

>1E

-5

T, m

²/s>1

E-8

>1E

-7>1

E-6

>1E

-5

T, m

²/s>1

E-8

>1E

-7>1

E-6

>1E

-5

T, m

²/s>1

E-8

>1E

-7>1

E-6

>1E

-5

T, m

²/s>1

E-8

>1E

-7>1

E-6

>1E

-5

T, m

²/s>1

E-8

>1E

-7>1

E-6

>1E

-5

Fig

ure

3-4.

Illu

stra

tion

of t

rans

mis

sivi

ties

mea

sure

d w

ith P

FL-to

ol.

Onl

y tr

ansm

issi

vitie

s hi

gher

tha

n 1·

10-8

m2/

s ar

e sh

own.

D

iffer

ent

colo

urs

refe

r to

the

mag

nitu

de o

f tr

ansm

issi

vity

and

dis

cs w

ith o

rien

tatio

n ar

e fit

ted

with

the

geo

logi

cal

data

base

of

frac

ture

s. U

nori

ente

d fr

actu

res

are

show

n as

hor

izon

tal s

quar

es. O

NK

ALO

is v

isua

lised

acc

ordi

ng to

con

stru

ctio

n si

tuat

ion

at th

e en

d of

Apr

201

0. O

NK

ALO

are

a is

show

n in

mor

e de

tail

on th

e ne

xt p

age.

30

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

Figure 3-4. Detailed illustration of the transmissivities of the ONKALO area.

3.2.2 Groundwater table and head

The compilation of the equipotential lines of the mean groundwater table (gw-level) was carried out for the first time in 1993 (Ahokas & Herva 1993). The equipotentials were updated for this report. No significant changes were detected although the network of the observation holes is at present much more comprehensive. The original version from the year 1993 was based on observations from 33 shallow holes and data from the VLJ repository area. In the update, data from 90 holes were used. The correlation between topography and the observed water-table levels (Figure 3-5) was utilised together with expert judgement on how the gw level is also dependent on the environment, i.e. it is significantly deeper on local hills and near the ground surface in local depressions. The effect of the depth of the observation hole on the measured water-table levels was also studied and a weak correlation was found (Figure 3-6) and a few holes were left out from the database utilised in the compilation of the equipotentials. The equipotential lines of the mean groundwater table and the observation points used for the compilation are visualised in Figure 3-7.

31

-1

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Ground surface (m.a.s.l.)

Gw

-leve

l (m

.a.s

.l.)

y = 0.1058xR2 = -0.3969

-1

0

1

2

3

4

5

0 5 10 15 20 25 30 35Hole depth (m)

Dep

th o

f the

wat

er-ta

ble

leve

l fro

m s

urfa

ce (m

)

Figure 3-5. Correlation between topography (elevation of the hole) and the observed mean of gw-level. Gw-level and ground surface coincide on the dotted line.

Figure 3-6. Correlation between the depth of observation hole and the mean of water-table level.

32

Fig

ure

3-7.

The

equ

ipot

entia

l lin

es o

f the

mea

n gr

ound

wat

er ta

ble

and

the

obse

rvat

ion

poin

ts u

sed

to d

efin

e th

e gr

ound

wat

er ta

ble.

33

Head has been intensively monitored deeper in the bedrock by means of multi-packers or measured in connection with flow logging. The compilation of the so-called baseline heads, characterising an undisturbed situation before the construction of the ONKALO started in 2004, was carried out in (Ahokas et al. 2008). Supplementary reference heads were defined for drillholes drilled after 2004 (Vaittinen et al. 2010a). The baseline heads are shown in Figure 3-8. The baseline heads are shown as in situ fresh-water head values, which in practice indicate the elevation of the water table within the measuring hose conducted from the observation section to the ground surface. The increase in head deep in the rock is thus caused by the increase in the density of groundwater over depth. The increase in density over depth is mostly caused by the increase in salinity over depth. The effect of salinity on the in situ fresh water head has been illustrated in the Figure 3-8 as two different reference curves (denoted as TDS head) – one curve illustrates the effect of salinity on the head below ground surface where groundwater level is at an elevation of 0 m.a.s.l. and the other where groundwater level is at an elevation of 7 m.a.s.l. In addition, the effect of the temperature and compressibility of water has been taken into account to illustrate the increase in head over depth in as natural (in situ) conditions as possible, i.e. they correspond to the head measured in observation holes equipped with multi-packers.

34

-1000

-900

-800

-700

-600

-500

-400

-300

-200

-100

00 5 10 15 20 25

Head, m.a.s.l.

Z, m

.a.s

.l.

KR1KR2KR3KR4KR5KR6KR7KR8KR9KR10KR11KR12KR13KR14KR15KR20KR23KR25TDS head gw=0 mTDS head gw=7 m

Figure 3-8. Baseline heads characterising an undisturbed situation before the construction of the ONKALO started.

3.2.3 Hydrogeology of new drillholes

Five new drillholes have been drilled from the ground surface since the previous version of the hydrogeological model; OL-KR49 � -KR53, as well as complementary shallow drillholes OL-KR50B, -KR52B, and -KR53B (Toropainen 2008c, 2009a – 2009d), and ONKALO pilot holes ONK-PH8 – -PH13 (Karttunen et al. 2009, 2010, Mancini 2010, Karttunen et al. 2011, Lahti et al. 2011, Aalto et al. 2011). All of the drillholes are located in the eastern part of the site (cf. Figure 1-2). Azimuth, dip, and drilled length are given for each new drillhole in Table 3-2. The starting points of drillholes OL-KR49 and -KR50 as well as drillholes OL-KR51 and -KR52 are located close to each other.

35

Table 3-2. Drilling data on new drillholes.

Drillhole Azimuth, deg Dip, deg Length, mOL-KR49 11.5 59.2 1060.22 OL-KR50B 293.1 63.5 45.44 OL-KR50 280.3 77.4 939.33 OL-KR51 28.9 59.4 650.55 OL-KR52B 349.5 69.9 45.04 OL-KR52 299.7 79.8 427.35 OL-KR53B 331.1 55.1 45.44 OL-KR53 330.2 54.8 300.48

Flow logging data were available from all of these drillholes for the present modelling campaign, but for drillhole OL-KR49 only down to a depth of 631.7 m of the total length of 1060.22 m due to the intensively fractured drillhole section (Väisäsvaara 2010, Pekkanen et al. 2010). The measured hydraulic conductivities of the new drillholes are visualised as fracture transmissivity values in Figure 3-9 and together with other drillhole data in Appendix 1.

Figure 3-9. Fracture transmissivities based on PFL measurements in new drillholes OL-KR49 – -KR53, -KR50B, -KR52B, and -KR53B. Horizontal squares refer to non-oriented fractures.

36

KR49_PAVEKR49_PAVE

KR50_PAVE

KR50B

KR51KR51

KR52

KR52KR52B

KR53

KR53B

KR49KR50

KR51

KR51

KR52

KR52KR52B

KR52B

KR53KR53B

KR53

KR53BKR51

KR49

KR55

KU2_Phase-1KU2_Phase-2



KU1_Phase-3

4313405938253660

-1

0

1

2

3

4

5

6

7

8

9

10

1.3.09 31.5.09 30.8.09 29.11.09 1.3.10 31.5.10

Date

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.a.s

.l.

0

20

40

60

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100

120

140

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220

KR49 Open M KR50 Open M KR50B Open M KR51 Open MKR52 Open M KR52B Open M KR53 Open M KR53B Open MONKALO DRILL CLP GWSPFL Reference fluctuation ONKALO chainage

Based on the available monitoring head data (cf. Figure 3-10), hydraulic connections occur between nearby drillholes. Contrary to most drillholes drilled during the last ten years, no indications of pressure responses caused by the drilling or pumping of the new drillholes were visible in the monitoring data of the old drillholes. Currently only one site-scale hydrogeological zone (HZ146) is modelled to intersect the new drillholes within the eastern part of the site.

Figure 3-10. Head diagrams of new drillholes OL-KR49 – -KR53, -KR50B, -KR52B, and -KR53B. Reference data include ONKALO chainage, grouting phases of shafts, ONKALO inflow, and reference fluctuation. The selected field activities affecting the head levels are also shown.

3.2.4 Assessment of transmissivity values

Fracture-specific transmissivity values are systematically measured with the PFL-tool. Head differences between rock and open holes cause flow from fractures into the hole or from the hole into fractures and transmissivities for single fractures can be calculated by measuring the flow rate and the open hole head, using conventional well equations.

Flow logging has been repeated in connection with the Monitoring Programme or for some other reason, and the determined transmissivities have been different in different campaigns. Fracture-specific transmissivities may therefore have a wide range and the determination of the most representative values is difficult. Factors such as the existence

37

n(all)=1870n(repeated)=1048

0

10

20

30

40

50

60

70

80

90

100

0.01 0.1 1 10 100

Tfinal/Told

Cum

ulat

ive

perc

ent

OL-KR1 � -KR31 Repeated holes

of open drillhole(s) nearby or disturbing activities such as pumping in a nearby drillhole have had an effect on the reported transmissivities. Some values that were the most disturbed, primarily due to pumping in a nearby drillhole, were assessed to be erroneous and other values or their average were used in the determination of the drillhole specific transmissivity for the zone.

In general, the maximum measured PFL-transmissivity value is used in this report. According to the evaluation of transmissivities (Ahokas & Pöllänen 2011), the measured maximum transmissivity in repeated holes has been evaluated to be too high for ca. 40 % of the cases (factor below 1) and too low for ca. 3% of the cases (factor above 1) shown as a cumulative plot in Figure 3-11. In addition, all the measured transmissivities are shown in the Figure and 24 % of the transmissivity values measured with PFL were assessed to be too high because of high noise or a smaller double-packer result etc. In the same evaluation work, it is assumed that the general accuracy of the determination of transmissivity is in the order of a factor range of ca. 0.4 – 3. Therefore over 90 % of the repeated values are within the range of accuracy and less than 10% of the values are assumed to be erroneous for one reason or another. These results are based on measurements carried out in drillholes OL-KR1 – -KR31. A more detailed list of possible reasons is provided in the evaluation report by Ahokas & Pöllänen (2011).

Figure 3-11. The factor between reported maximum of transmissivity (Told) and transmissivity after evaluation (Tfinal), i.e Tfinal / Told for repeated tests and for all measured data in evaluated drillholes OL-KR1 – -KR31.

38

0

10

20

30

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50

60

70

80

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100

-10 -9 -8 -7 -6 -5 -4 -3

log T (zone/drillhole and single fractures)

Cum

ulat

ive

perc

ent

Old zone T New zone T Old rock T New rock T

The effect of the evaluation work on the determined statistics of the transmissivity of zones and rock was also studied. Although some local high differences for drillhole specific transmissivities were found, the effect of the evaluation on the average (geometric mean and median) or standard deviation of all the data analysed so far (OL-KR1 – -KR31) was minor. The summary of old and new drillhole specific transmissivities are shown in Figure 3-12 as cumulative plots. The geometric mean of the old transmissivities for drillhole specific sections is 2.5·10-6 m2/s and the new one is 2.1·10-6 m2/s. The calculated medians are 4.4·10-6 m2/s and 3.4·10-6 m2/s, respectively. The corresponding plots for rock outside the deterministic zones are shown in Figure 3-12, also. The basic statistics for zones and averagely fractured rock are shown in Table 3-3.

Figure 3-12. Summary of old and new drillhole specific transmissivities for deterministic zones and for averagely fractured rock as cumulative plots based on data from drillholes OL-KR1 – -KR31.

39

Table 3-3. The basic statistics of old and new data on transmissivities from drillholes OL-KR1 – -KR31.

Rock type Average (geom. mean) Median St.Dev. Zones old 2.5E-06 4.4E-06 1.08 Zones new 2.1E-06 3.4E-06 1.07 Rock old 1.4E-08 1.4E-08 0.92 Rock new 1.2E-08 1.2E-08 0.92

3.2.5 Analysis of flow conditions

Changes in flow Flow logging includes the measurement of the exchange of water between rock and an open hole. Head differences between rock and open holes cause flow from fractures into the hole or from the hole into fractures. A measuring section is typically 0.5 or 2 m long. Flow measurements have been repeated for the selected drillholes either in connection with the Monitoring Programme or for testing hydraulic connections between the drillholes by pumping in one drillhole and measuring flow responses at the location of hydraulically transmissive fractures in other nearby drillholes. The results of the repeated measurements can be compared with the results measured in as undisturbed conditions as possible to determine if any changes have taken place in the flow. Changes in the flow are usually caused by pumping in a nearby drillhole and the direction of the change can be analysed to find out which fractures are connected to the pumped drillhole. A more detailed description of the analysis of flow responses is given in Vaittinen et al. (2009b).

Changes in hydraulic heads determined in connection with flow logging Hydraulic connections between drillholes can also be seen in the calculated fracture-or section-specific flow heads determined in connection with flow logging. Whether fracture-specific or section-specific flow heads are determined, depends on the length of the PFL-tool, i.e. either 0.5 m or 2.0 m, respectively. The calculated flow heads are based on pairs of measured flow and drillhole fresh water head (cf. e.g. Öhberg & Rouhiainen 2000). If there is a hydraulic connection between the drillholes, the heads have changed compared with undisturbed conditions and decreased due to pumping and drawdown in the nearby drillhole (cf. Vaittinen et al. 2009b).

Measurements The flow conditions have been measured in drillholes OL-KR4 and -KR27 during 2008 and in drillholes OL-KR22, -KR30, -KR31, -KR35, -KR36, and -KR40 during 2009 with the PFL-tool as part of the monitoring programme (Vaittinen et al. 2009a, 2010a). The 2009 results were somewhat disturbed, because when drillholes OL-KR35, -KR36, and -KR22 were measured, drillhole OL-KR22 was open and probably changed groundwater flow along OL-KR22 down to the leaking HZ20 system. The 2009 results are therefore not fully comparable with each other.

40

3.2.6 Analysis of head observations

Hydraulic connections have been studied in deep drillholes by analysing the measured hydraulic heads. The analysis is based on the observed changes in the head caused by the investigation activities carried out on the site. The observed hydraulic heads in the packed-off drillholes have been studied in two periods, from the beginning of the measurements in 1991 until the end of 2005 (Vaittinen et al. 2008b) and during years 2006 – 2009 (Vaittinen & Pentti 2011). Many uncertainties are related to the interpretation of pressure responses, cf. the uncertainty assessment in Chapter 2.3 in Vaittinen et al. (2008b).

The analysis of the head observations suffered from the open drillholes, which spread head changes to all the intersected hydrogeological zones, until June 2008, when a considerable improvement allowing undisturbed head observations to be gathered took place. Before the penetration of the HZ20 system by the ONKALO access tunnel, all deep drillholes close to ONKALO were packed off to isolate the hydrogeological HZ19 and HZ20 systems from each other, cf. Figure 3-13. The last nearby drillhole, OL-KR4, was packed-off on 23.6.2008. After that, monitored heads recovered to zone-specific levels and only drillhole OL-KR40, interpreted to intersect both hydraulic features, remained open. Drillhole OL-KR40 is located close to the interpreted boundary of the HZ20 system, and compared with most of the HZ19 and HZ20 drillhole intersections, the transmissivity is one order of magnitude lower.

The analysis of the head data gathered during 2006 – 2009 supports the concept of the main modelled hydrogeological systems (Vaittinen & Pentti 2011). The events causing the analysed pressure responses consist mainly of pumping of deep drillholes during flow measurements, and leaks from the main hydrogeological zones into the ONKALO through pilot holes, probe holes, and grouting holes. For example, the drawdowns resulting from an inflow in July 2008 through pilot hole ONK-PH8, which intersects the HZ20 zone, were analysed (cf. Chapter 5.4.2). The results clearly indicate that the effect of the inflow propagates especially well eastwards in the HZ20B zone, while north of ONKALO the response is much weaker at corresponding distances. Also, within the HZ20A sections there is a significant difference in the propagation of the pressure response between the ONKALO area and to the north of it. This and several other cases of inflow from the HZ20 zones into ONKALO support the conclusion that the sub-vertical zone OL-BFZ100 does not obstruct groundwater flow along the HZ20 system towards east whereas the hydraulic connectivity of the system decreases towards the northern edge of the ONKALO area outside the interpreted Flutanperä Deformation Zone (FDZ) (cf. Chapters 4.1 and 5.4.2).

As an additional assessment, pressure responses were analysed for a half year period when the ONKALO access tunnel was excavated through the HZ20 system (Vaittinen et al. 2010b). The results of the analysis are given in Chapter 5.4.2.

Another illustrative example of the pressure response analysis is presented in Figures Figure 3-14 and Figure 3-15. The studied event is a leak from grouting holes ONK-PP191 – -PP196 on 10.8.2009 and 11.8.2009. The holes intersect the HZ20 system near the ONKALO, but the effect of the leak is spread to the upper HZ19 system via drillhole OL-KR22, in which the pressure-insulating packers were out of order at the

41

time of the leak. The propagation of the response in the HZ19 system is plotted in Figure 3-14 as a function of distance from drillhole OL-KR22. The next figure shows the time-dependence of head in some of the HZ19 sections. The drawdown induced by the leak decreases rather regularly with distance, especially if one considers for each drillhole only the section in which the drawdown is largest. Similarly with the first example that concentrated on the HZ20 system, the drillholes to the north of the ONKALO; OL-KR12, and -KR15 – -KR18 make an exception to the general trend by exhibiting a remarkably small and slow response, see the data plotted in black and grey in Figure 3-15. This observation, together with similar features in the effect of the OL-KR22 packer failure itself, discussed in Chapter 5.2.2, indicates that the hydraulic connectivity of the HZ19 system is weaker towards north outside FDZ.

42

Figure 3-13. Monitoring drillholes in July 2004 when the excavation of the ONKALO access tunnel started and in July 2008 when penetration through the HZ20 system started. Blue refers to a packed-off section and green to an open drillhole. Drillholes OL-KR24, -KR38, and -KR48 were closed.

43

Figure 3-14. Head responses in packer sections intersecting the HZ19 system during leak in shaft grouting holes in August 2009, plotted as a function of distance from drillhole OL-KR22.

44

Figure 3-15. Heads in selected packer sections intersecting the HZ19 system during leak in shaft grouting holes. Each dataset has been shifted to zero at the beginning of the event to facilitate comparison of responses.

3.3 Geophysical data

Geophysical studies on the Olkiluoto site cover a wide selection of investigation methods carried out since 1988. A detailed description of the measurements as well as references and the use of the data in the compilation of geological model version 2.0 are presented in Aaltonen et al. (2010).

Only a list of the applied investigation methods is given in this Report. Airborne geophysics includes the following data: magnetic total field and vertical gradient data, multi-frequency electromagnetic (EM) data, Very Low Frequency (VLF) data, and radiometric K, U, Th, and total intensity data. Geophysical ground surveys comprise magnetic data, horizontal-loop (HL) EM (Slingram) data, wide-band EM soundings, impulse radar soundings, and seismic refraction and 3D reflection data. As a new seismic method, a high resolution deep reflection seismic imaging (HIRE) survey was carried out in 2008 (Kukkonen et al. 2010).

Subsurface measurements include single-hole measurements, cross-hole measurements and measurements in the ONKALO tunnel. The applied single-hole investigation methods comprise seismic, electric, magnetic, radiometric and gamma-ray spectrum,

45

thermal, and caliper measurements. Seismic measurements between ground surface and the drillhole have been carried out using geometries: Vertical Seismic Profiling (VSP) and Walkaway VSP (WVSP), and Horizontal Seismic profiling (HSP) has been performed on the seashore and in the Korvensuo reservoir. Cross-hole measurements between two drillholes have also been performed as well as two 3D reflection seismic surveys on the ground surface and in the ONKALO tunnel. Mise-à-la-masse surveys have been carried out using current earthing in several drillholes as well as in the ONKALO. Potential distribution has been measured in drillholes and during some of the earthings on the ground surface. In addition, petrophysical properties have been measured of samples from outcrops, the VLJ-repository, and drillholes.

As regards the interpretation of hydrogeological zones, cross-hole and 3D measurements are particularly interesting and provide information on the continuity of physically anomalous features.

Seismic surveys

High resolution deep seismic reflection survey HIRE was carried out in the Olkiluoto area and the surroundings in 2008 by the Geological Survey of Finland (Kukkonen et al. 2010). A schematic geological modelling of the HIRE line V1 is presented in Figure 3-16. The results of the HIRE survey improve the modelling of the regional and site scale structures. The data have already been used in geological modelling (Aaltonen et al. 2010) and in support of the modelling of the Mise-à-la-masse survey data in the eastern part of Olkiluoto Island (Ahokas 2010).

The images and amplitude block models produced from the 3D seismic survey data from the site area in 2006 and from the eastern area in 2007 (Juhlin & Cosma 2007, Cosma et al. 2008) have been used in geological modelling (Figure 3-17). The data include useful information on gently dipping structures and also by implication on steeply dipping structures.

In the ONKALO tunnel, one seismic survey was carried out in 2007 and another in 2009. The modelling of the data is in progress but some of the data have been already used in geological modelling. The 2009 survey was targeted at the demonstration area and the first planned repository panel area. Several fractured zones, lithological contacts and tunnel cutting fractures were detected from the data.

Mise-à-la-masse survey The Mise-à-la-masse technique is an electrical resistivity method that has been conventionally used in ore prospecting for delineating electrically conductive subsurface ore bodies. It has proven a potential method also in different kinds of environmental investigations, but the significantly weaker conductors result in complexity of interpretation. Updated and integrated modelling of Mise-à-la-masse survey data gathered in Olkiluoto since 1995 has been performed by Ahokas & Paananen (2010) and new investigations carried out in the eastern area of the site during autumn 2010 were combined with the results by Ahokas (2010). The approach applied to modelling was to find geologically reasonable connections or zones.

The interpretation results of the Mise-à-la-masse survey indicate extensive continuity of the conduits following the common orientation of foliation, cf. Figure 3-18.

46

Fig

ure

3-16

. Vis

ualis

atio

n of

HIR

E lin

e V1

. Ref

lect

ors w

ith h

igh

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he b

ound

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BFZ

stan

ds fo

r br

ittle

frac

ture

zon

e (K

ukko

nen

et a

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10).

47

Figure 3-17. Seismic 3D data as amplitude block models, year 2006 and 2007 surveys. Only blocks with the highest (> 0.5 for 2006 survey and > 1.8 for 2007 survey) amplitudes are shown (Juhlin & Cosma 2007, Cosma et al. 2008, and Aaltonen et al. 2010). View towards northeast.

Figure 3-18. Interpreted extensive electrical conduits based on Mise-à-la-masse survey (Ahokas & Paananen 2010, Ahokas 2010), view towards east-northeast.

48

49

4 HYDROGEOLOGICAL CHARACTERISATION OF THE SITE

A hydrogeological characterisation of the Olkiluoto site is given in the next Chapters following the hypothesis of the effect of the tectonic units on the hydrogeological properties of the rock mass.

Observation of local hydrogeological features is strongly dependent on the location of the drillholes, on whether the drillholes are open or packed-off, and on the position of the packed-off sections. However, in addition to site-scale features, all available information on interpreted local-scale features is given as well to provide background data for e.g. groundwater sampling and the construction of the ONKALO.

4.1 Geological background

The site is divided into three main tectonic units, which can be divided into several sub-units. Tectonic units and sub-units are modelled in the geological ductile deformation model (Aaltonen et al. 2010). Based on the current understanding of the site, the main effect of the tectonic units, from a hydrogeological point of view, is related to the hydraulic connections between the units. Generally connections seem to occur within each of the main units and connections between units are weak. The highest fracture transmissivities and hydraulic connections are possibly related to brittle structures following the ductile deformation structures, where one ductile deformation phase is dominant comprising more homogeneous foliation than the surrounding bedrock. The reactivation of the ductile and semi-ductile deformation structures within later brittle deformation may have produced open channels for groundwater flow.

Ductile deformation features

The main focus of the ductile deformation model is to define structural units, which can be considered "statistically homogeneous" with respect to a particular parameter or parameters, in this case the orientation and type of foliation, the orientation of axial surfaces, and the supposed deformation intensity of a particular deformation phase (Aaltonen et al. 2010). Due to the statistical character of the ductile model, the modelled tectonic units and sub-units do not form exact boundaries, but offer a basis for the assessment of the observed hydrogeological properties. Olkiluoto Island consists of three tectonic units; the Northern Tectonic Unit (NTU), the Central Tectonic Unit (CTU), and the Southern Tectonic Unit (STU), which are clearly defined on the basis of the magnetic map (cf. Figure 4-1). These tectonic units are bordered by deformation zones, which divide the major units into sub-units and in which shear-related structures are important elements.

The Northern Tectonic Unit (NTU) is characterised by E-W striking planar structural elements that dip 40 – 50° southwards, and by sub-parallel, elongate tonalitic-granodioritic-granitic (TGG) gneiss and pegmatite granite units. The products of D2 deformation are the dominant elements within the unit, and they are locally overprinted by coplanar products of D3 deformation. Typical D2 elements include various thrust-related elements, such as overturned folds and shear bands, which are characterised by blastomylonitic and migmatitic fault rocks. The Selkänummi Deformation Zone (SDZ) in the southern part of NTU is a product of multiple stages of ductile deformation,

50

which all share an E-W strike of planar elements (S2 axial surface foliation, blastomylonitic foliation, migmatite structures of D2 faults, D3 shear structures formed (sub)parallel to S2 foliation).

With the exception of its western part, the Central Tectonic Unit (CTU) is intensely affected by D3 deformation. Pervasive S3 foliations, migmatite structures and wide pegmatitic granites or units rich in granitic leucosome all strike NE – SW within CTU. CTU is divided into three sub-units (CTU1, CTU2 and CTU3) by strongly sheared and deformed zones, Flutanperä Deformation Zone (FDZ) dipping to the SE and two D4 deformation zones, D4-1 and D4-2 situated a few hundred metres east of FDZ and striking NNE-SSW and dipping to the ESE.

The Southern Tectonic Unit (STU) is characterised by large blocks dominated by D2

structures. They have been preserved close to their original orientation, e.g. axial plane traces of F2 folds strike E-W. Foliations within STU dip 50 – 70° southward. Like in CTU, the dips of the planar elements are steeper in the eastern parts than in the western parts of this unit.

In the southern part of the study site, a NE-SW striking and SE dipping ductile shear zone (the Liikla Shear Zone) defines the northern border of STU and is the northern part of it. Liikla Shear Zone (LSZ) is mainly composed of shear-related structures created by deformation phases D2 and D3. The detailed internal structure of this shear zone is difficult to outline, but its regional location can be reliably defined by direct observations and on the basis of the geophysical maps. Also, a feature interpreted from HIRE results coincides approximately with LSZ. The orientation maximum of all foliations measured from LSZ is 165/60°.

Ductile D4 deformation structures have a scattered occurrence over Olkiluoto Island, but they are most prominent in the central and southeastern parts of the area. They appear as NNE-SSW striking zones which vary in width from narrow cm-scale bands to 200 – 300 m wide zones intensely deformed by D4. Two intensely D4 deformed, NNE – SSW striking zones have been defined (D4-1 and D4-2), located in the central and eastern parts of Olkiluoto, respectively. Both zones are interpreted as eastward-dipping ductile shear zones along which the hanging wall blocks were thrusted westward.

The ductile deformation model (Aaltonen et al. 2010) is visualised in Figure 4-2. In addition to tectonic units and corresponding dividing deformation zones, NE-SW striking FDZ related to the third deformation phase, and two NNE-SSW striking intensively deformed D4 zones (D4-1 and D4-2) as well as several S4 axial surfaces are shown.

51

Figure 4-1. Major tectonic units shown on an aeromagnetic map (Aaltonen et al. 2010).

52

SDZ

D4-1

FDZ

LSZ

S4

SDZ

D4-1

FDZ

LSZ

S4

SDZ

D4-1

FDZ

LSZ

S4

Figure 4-2. The tectonic units and major ductile deformation zones of Olkiluoto Island (upper) and 3D model of the tectonic units and tectonic sub-units (Aaltonen et al. 2010). View towards northeast.

53

T, m²/s>1E-6>1E-5

T, m²/s>1E-6>1E-5

D4-1

FDZ

LSZ

S4

SDZ

T, m²/s>1E-6>1E-5

T, m²/s>1E-6>1E-5

T, m²/s>1E-6>1E-5

T, m²/s>1E-6>1E-5

D4-1

FDZ

LSZ

S4

SDZ

Two of the main hydrogeological systems, HZ19 and HZ20 are more or less restricted to CTU, and the question arises, what is the connection between the ductile deformation model and the hydrological model. The HZ19 and HZ20 systems are closely connected to low-angle brittle fault zones OL-BFZ019 and OL-BFZ020. These brittle structures are interpreted to have ductile precursors, gently dipping thrust faults formed during deformation phase D3, which is strongly concentrated in CTU (Aaltonen et al. 2010). These low-angle faults show prominent reverse dip-slip movement. The slip directions trend mainly towards the ESE-SSE, indicating thrusting associated with approximately NNW-SSE to WNW-ESE oriented contraction during the ductile regime (Mattila et al. 2008). In subsequent brittle deformation, the existing faults merely slipped parallel to the previous reverse-slip direction, but now as normal faults (Mattila 2009). Brittle faulting was thus markedly influenced by the pre-existing planes of weakness formed during earlier ductile deformation (see discussion in Aaltonen et al. 2010). The brittle reactivation of the ductile structures opened channels for groundwater flow.

Figure 4-3. The major ductile deformation zones of Olkiluoto Island and transmissive fractures, view towards northeast.

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Brittle deformation features

In the brittle deformation model, the deformation zones are divided into fault zones and joint zones (Mattila et al. 2008, Aaltonen et al. 2010). In Olkiluoto, fault zones have been conceptualised as consisting of one or several fault core zone(s), bounded (or separated) by zones of influence (corresponding to “damage zones” in the scientific literature (cf. Milnes 2006). Fracturing related to fault zones is strongly concentrated in the zones of influence adjacent to the fault core zone, where the main movement has occurred, or around the fault tip. The typical architecture of the fault zone is shown schematically in Figure 4-4. A fault core consists of incohesive or low-cohesive fault gouge, fault breccia and/or crush rock, accompanied by slickensided fractures and signs of displacement. Fault cores are typically heterogeneous, discontinuous and have anastomosing and branching traces. Also several fault cores within one fault zone intersection may exist.

Zones of influence, in which deformation during movement was less intense than in the fault core zone(s) and gradually diminishes towards the outer margins of the zone, occur on each side of the fault core. The zones of influence are typically characterised by shear fractures, increased fracturing compared with the averagely fractured surrounding rock, en echelon zones of tension gashes and other brittle structures, commonly in complex arrays, and also commonly associated with alteration (cf. Milnes et al. 2007). Both pervasive and fracture-controlled hydrothermal alteration may be present inside the core zone and also extend to the zone of influence. The altered parts may be more porous, mechanically different from and hydraulically more conductive than fresh rock. Moreover, the zones of influence are frequently seen as geophysical anomalies (particularly on acoustic logs, Long Normal and Short Normal resistivity logs, sometimes also P-wave velocity or single point resistance anomalies). The geophysical anomalies reflect the properties of the rock matrix that cannot always be seen clearly with the naked eye (e.g. porosity, alteration), so if they are clearly anomalous and continuous, the influence zone has been continued to include the whole anomaly. The zones of influence can be hydraulically much more conductive than averagely fractured rock or the fault core (cf. Caine et al. 1996, Gudmundsson 2001). In some circumstances, the influence zone is the main water-conducting zone within the fault zone (cf. Caine et al. 1996), and the core may be quite impermeable (e.g. when the fault core contains abundant clay minerals). Zones of influence may have highly variable width (metre to 100 m scale) and internal properties from one location to another. The influence zone has so far been only defined for site-scale zones OL-BFZ019C, -BFZ020A, -BFZ020B, -BFZ021, and -BFZ099.

There is commonly a genetic relationship between older ductile and/or semi-brittle shear zones formed at lower levels in the crust and younger fault zones developed at the same location, under a similar stress regime but at a higher crustal level.

55

Figure 4-4. Conceptual model of the architecture of a single fault zone, consisting of a complex branching fault core zone (indicated in black) and an equally complex zone of influence (whose outer margins are indicated by dashed lines). Subsidiary faults may exist close to the main fault zone and these may be located either within the zone of influence or outside it (surrounded by its own zone of influence), depending on its distance from the main fault zone (Aaltonen et al. 2010).

A joint zone is a narrow zone of closely-spaced joints, i.e. fractures, which show no signs of movement parallel to the fracture surface. The most obvious signs of movement, the presence/absence of which will be systematically checked on every fracture, are (1) the presence of slickenside striations on the fracture surface, and (2) a misfit of country rock heterogeneities (e.g. leucosome in migmatites) across the fracture. The lack of these two easily observed features is taken to indicate that the fracture (discontinuity) in question is not a fault but what is called a joint in geological literature. Due to the lack of a general understanding of the geometries and mechanisms of joint zones (see discussion in Aaltonen et al. 2010), and due to the observation made

56

in Olkiluoto that fault zones are far more common than joint zones, the main emphasis of brittle deformation modelling has been on characterising and visualising fault zones. A total of 81 brittle joint zone intersections have been identified in the drillholes, 64 of them with orientation data.

The site-scale brittle fault zones and hydrogeological zones are not straightforwardly comparable, the brittle fault zones in many cases having a much larger extent compared with the corresponding hydrogeological zone. An explanation to this difference may lie behind the architecture of the fault zone. The core zones of the fault zones are not laterally uniform but the core zones of the same fault may have different kinds of structures including single slickensides, breccia zones, altered zones, cataclasites and gouges. These different structures have different kinds of effects on the porosity and permeability of the zone, and thus, control groundwater flow (see Caine et al. 1996). E.g. in Olkiluoto, the brecciated zones are often welded, i.e. the fractures are later filled with minerals, creating an impermeable zone, which acts as a barrier to groundwater flow (see also Gudmundsson 2001). The effect of alteration on water-conductivity is well demonstrated in brittle fault zone OL-BFZ020 in ONKALO, where alteration is negligible, whereas the corresponding hydrogeological zone HZ20 has high water-conductivities (cf. Chapter 5.4). In case of brittle fault zones OL-BFZ021 and -BFZ099, the fault core contains fault gouge, clay-filled-fractures and alteration products, which is probably why only fragmental connections exist between the drillholes in corresponding hydrogeological structures HZ21 and HZ099 (cf. Chapter 5).

The heterogeneity of the fault zone leads to segmentation of the groundwater flow, when the flow along the fault zone is in some places enhanced and in other places retarded or prevented depending on fault core structure. Consequently, the extent of the hydrogeological zone does not have to be the same as the extent of the fault zone. A good example of the effect of heterogeneity of the fault zone on groundwater flow is provided by low-angle fracture zone Zone 2 on the Finnsjön study site in Sweden, where there are large contrasts in hydraulic conductivity along the zone, the highest conductivities being concentrated into narrow sub-zones (Andersson et al. 1991). The structural anisotropy is also on the Forsmark study site in Sweden accompanied by substantial hydraulic heterogeneity both vertically and laterally (SKB 2008).

On the other hand, in some cases hydraulic connections cover a much larger area than the corresponding brittle fault zone. In some drillhole sections without geological evidence of a brittle deformation zone, the transmissivity of a distinct fracture may be in the order of 1·10-5 m2/s. It is possible that the fault has a similar extent as the hydrogeological zone but due to the natural variability of the fault zone from one location to another there may be sections with a poorly developed or even non-existent core and zone of influence. It is also possible that it is caused by a failure to correctly identify all the sequences of brittle fracturing in drill cores due to lack of proper indicators, leading to an erroneous 3D model, especially when considering continuities of modelled fault zones.

4.2 Hydrogeological concept

The hydrogeological site-scale concept of the site is based on coinciding spatial information on the interpreted tectonic units, BFZs with drillhole-to-drillhole

57

connections largely based on geophysical connections, especially Mise-à-la-masse conduits, and high fracture transmissivities and hydraulic connections.

The interpreted hydrogeological connections are visualised against the tectonic units in Figure 4-5 and Figure 4-6 to assess the current hypothesis of the hydrogeological properties of the site. According to the hypothesis, the hydraulic connections generally seem to occur within each tectonic unit and connections between the units are poor. Conclusions based on hydraulic connections are preliminary due to the concentrated location of deep drillholes within CTU. Only five drillholes are full-length within NTU and one drillhole within STU. However, many of the packed-off CTU drillholes are partly located within NTU and one within STU, supplementing information on the tectonic units.

Due to substantial temporary drawdowns caused by inflows into the ONKALO access tunnel and the shafts, hydraulic connections between NTU and CTU can be assessed. The assessment of hydraulic connections between CTU and STU, on the other hand, is so far based on one packed-off drillhole and the result cannot be generalised.

Thirteen site-scale hydrogeological features have been interpreted within Olkiluoto Island. Twelve of them are mostly based on hydraulic properties and the continuity of the interpreted hydraulic connections, and one is based on geological indications. In addition to the site-scale features, some hydraulic connections are assessed as local-scale features. The applied hypothesis is supported by the results of geophysical measurements, especially extensive electrical Mise-à-la-masse connections, which coincide with brittle structures, following the ductile deformation structures and hydraulic connections.

Northern Tectonic Unit

Drillholes OL-KR1, -KR2, -KR4 – -KR7, -KR11 – -KR15, -KR19 – -KR21, -KR33, -KR41 – -KR43, -KR46, and -KR47 are either full-length or partly located within NTU. The interpreted hydraulic connections related to these drillholes are visualised in Figure 4-5. Drillholes OL-KR6, -KR21, -KR33, -KR41 – -KR43, -KR46, and -KR47 have never been packed-off and distances between some of the drillholes are long, which is why the interpretation of the monitored head observations is more uncertain within NTU than within CTU. Only a few hydraulic connections have been observed within NTU, mostly related to pressure responses during drilling of a new drillhole. However, drillholes located partly within CTU and partly within NTU provide supporting data to the current concept of hydraulic connections. Due to the geometry of the observation, i.e. NTU dipping towards south and the drillholes mostly drilled towards northeast, the upper parts of the drillholes and the associated hydraulic connections are within CTU and the lower parts within NTU (Figure 4-5).

Drillholes OL-KR1, -KR5, -KR11, -KR12, and -KR20 are currently or have been packed-off and while the topmost monitoring sections respond to the temporary inflows into the ONKALO access tunnel and the shafts, i.e. towards south, the lower sections either have indications of hydraulic connections towards north or no responses have been interpreted. Packed-off drillhole OL-KR13 and open drillhole OL-KR46 have the southernmost location without any indications of hydraulic connections towards south so far. A more detailed description of the interpreted pressure responses is provided in Vaittinen & Pentti (2011).

58

SDZ

SDZ

SDZ

SDZ

Figure 4-5. Interpreted hydraulic connections in drillholes located either full-length or partly within NTU. Hydraulic connections within NTU (red) and connections within CTU (green) are visualised. The latest packed-off combination applied in each of the drillholes is shown. View from above (upper) and view along SDZ (lower).

59

Central Tectonic Unit

Most of the deep drillholes are located either full-length or partly within CTU and they are mainly packed-off. The drillholes are OL-KR1 – -KR5, -KR7 – -KR12, -KR14 – -KR18, -KR20 – -KR32, -KR34 – -KR40, -KR42, -KR44, -KR45, and -KR48 – -KR52.

CTU is divided into three sub-units by FDZ and by the NNE-SSW striking D4 zone (D4-1), cf. Figure 4-3. The difference between the sub-units is visible in the statistics of the orientation of foliation. The dip direction of foliation changes from south to southeast and the dip of foliation changes more steeply from western CTU1 towards eastern CTU3 (Aaltonen et al. 2010).

The major hydrogeological systems modelled within the Olkiluoto site so far, HZ19 and HZ20, are located within CTU. The interpreted hydraulic connections are visualised in Figure 4-6. In addition, hydraulic connections assessed as local-scale features have been observed especially within CTU1 (Figure 4-6).

Southern Tectonic Unit

Drillholes OL-KR27, -KR40, -KR45, and -KR49 – -KR52 intersect boundary sub-unit LSZ between CTU and STU. Only drillhole OL-KR53 is located full-length within STU. Drillhole OL-KR27 is packed-off, the other drillholes are open. Drillholes OL-KR49 � -KR53 were drilled in 2009, so only a short period of head observation is available for assessing the hydrogeological properties of STU. As discussed in Chapter 3.2.3, hydraulic connections seem to occur between drillholes having starting points nearby, but the geometries of these connections are not known.

High fracture transmissivities seem to occur in close vicinity of southern E–W striking boundary sub-unit LSZ. Five out of the ten anomalous fracture transmissivity values determined in new drillholes OL-KR49 � -KR53 are interpreted to be connected to brittle zone OL-BFZ146 following LSZ.

LSZ is dipping moderately towards southeast. An indication of the effect of LSZ on hydraulic connections is visible in drillhole OL-KR27 drilled towards northwest intersecting LSZ. The topmost monitoring sections down to a depth of ca. 100 m do not respond to inflows into the ONKALO. These sections are assessed to be located within STU. Monitoring sections between ca. 100 m and 300 m, on the other hand, have similar responses with sections in the depth range of ca. 40 – 200 m in drillholes located within CTU. In other words, hydraulic connections do not intersect LSZ but change their direction to follow it underneath.

60

Figure 4-6. Interpreted hydraulic connections in drillholes located either full-length or partly within CTU. Hydraulic connections within CTU (green) are visualised. The latest packed-off combination applied in each of the drillholes is shown. View from above (upper) and view along LSZ (lower).

61

5 DESCRIPTION OF HYDROGEOLOGICAL SITE-SCALE STRUCTURES

The 2010 hydrogeological structure model version is an upgrade from the 2008 version. Zone HZ039 based on hydrogeological investigation data and zone OL-BFZ100 based on geological data were added to the model as new HZs. The label of zone OL-BFZ100 was not changed, because no modifications were made. Zone HZ004 was replaced by zone HZ146, which follows the Liikla Shear Zone and brittle fault zone OL-BFZ146. Zone HZ21B was included in the basic model based on new geophysical survey data. In addition, some changes based on new investigation data and on applied depth dependent limit transmissivity values have been made. A summary of changes made in the structure model since the version 2008 is listed in Table 5-1. Minor changes in drillhole intersections were caused by the adoption of fracture-specific transmissivity values instead of two-metre hydraulic conductivity (K2m) values. All the hydrogeological zones included in the basic model are visualised in Figure 5-1.

As a result of a systematic analysis of the occurrence of anomalous fracture transmissivities (cf. Chapter 2.4.1), a total of 35 anomalous fractures were considered. 27 of the fractures are located outside the hydrogeological zones of the 2008 model and 8 fractures in new drillholes. 15 fractures out of the 35 were connected to the modelled HZ001, HZ099, HZ19, and HZ20 zones, and 7 fractures to new zones HZ039 and HZ146. Ten out of the remaining 13 anomalous fractures could not be connected either to a site-scale or to a local-scale hydrogeological feature, but were included in the data on sparsely fractured rock (cf. Chapter 6).

Table 5-1. Summary of changes made in the hydrogeological structure model since the 2008 version.

Zone New zones and modifications to geometry since 2008 HZ001 Extended towards east to intersect drillhole OL-KR6 HZ004 Replaced by zone HZ146 HZ008 Geometry fixed with electrical Gefinex and seismic HIRE data HZ19A Drillhole intersections were changed HZ19B Drillhole intersections were changed HZ19C Drillhole intersections were changed HZ20A Extended to intersect drillholes OL-KR8, -KR16, and -KR27

Added intersection in pilot hole ONK-PH8 Intersection in drillhole OL-KR29 changed upwards

HZ20B Extended towards southeast following seismic HIRE and 3D data Added intersection in pilot hole ONK-PH9 Connected northern border to zone HZ20A

HZ21 Extended towards east and west to intersect bounding lineaments New intersection in drillhole OL-KR47

HZ21B No changes, moved to the basic model HZ039 New zone, orientation based on OL-BFZ039 HZ099 Extended towards east to intersect drillholes OL-KR6 and -KR12

BFZ100 Included in the HZ model without modifications HZ146 Zone based on OL-BFZ146, i.e. brittle part of Liikla Shear Zone

Intersections in drillholes OL-KR27B, -KR40B, -KR45, and -KR49 – -KR52 Bounding lineaments

Northern lineament replaced by OL-BFZ214 Drillhole OL-KR53 intersects southwest lineament, but the BFZ was not modelled in GSM 2.0

62

One of the objectives is to assess possible flow routes. Considerable flow routes may occur from the planned repository to the biosphere, or enable upconing of saline groundwater, or enable hydraulic connections to the sea. The modelled site-scale BFZs were therefore all parameterised for numerical modelling purposes. From the hydrogeological modelling point of view, BFZs without any drillhole intersections and BFZs intersecting at most a few drillholes were classified as possible hydrogeological zones. These zones are used in the numerical EPM sensitivity analysis.

Reporting of structures

The reporting of the hydrogeological site-scale features consists of two stages. The first stage contains a description of the hydrogeological properties of the feature and an assessment of the properties against the geological ductile deformation model. The second stage describes the modelling of the HZ zones, i.e. the geometry and hydraulic properties, and the relationship with the corresponding BFZ. The use of the structure model in site-scale numerical EPM groundwater flow modelling and statistical DFN modelling, i.e. hydraulic connectivity within the model, is taken into account in the modelling of the geometry for the hydrogeological zones.

The drillhole intersections determined for the zones and for the transmissivity depth ranges and the transmissivities of the zones are both tabulated and visualised. 3D visualisations containing both the hydrogeological zones and the corresponding BFZs are shown. For hydrogeological zones, which do not have a corresponding site-scale brittle deformation zone, repository-scale brittle deformation zones have been studied. A more detailed comparison between the modelled drillhole intersections of the corresponding zones is shown in Appendix 1.

3D visualisation of the structure model

The 3D visualisations of the zones presented in this Chapter contain the following information: hydrogeological zones, corresponding brittle deformation zones, fracture transmissivities, the ONKALO, the shoreline of the island, and a volumetric grid of 500 m.

The hydrogeological zones are presented with constant colours, cf. Figure 5-1. However, the rendering of the 3D visualisations shows the colours somewhat varying depending on the view direction. All corresponding brittle deformation zones are presented in grey. The ONKALO, the shoreline of the island, and the grid are shown in white or light grey.

The transmissive fractures are visualised as oriented discs. Fractures without orientation are shown as horizontal squares. For drillhole OL-KR39 and extended parts of drillholes OL-KR23 and -KR31, all fractures are unoriented. In other drillholes most of the fractures are oriented (Tammisto et al. 2009, Palmén et al. 2010, Tammisto & Palmén 2010). To improve visualisation, only fracture transmissivities above 1·10-8 m2/s are shown in the Figures of this Chapter. Each colour refers to a transmissivity (T) of one order of magnitude: light blue to 10-8 m2/s, green to 10-7 m2/s, yellow to 10-6 m2/s, and red to 10-5 m2/s.

63

HZ008

HZ146

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

HZ21

HZ039

HZ21B

HZ20A

HZ20B

HZ19A

HZ19C

HZ19B

BFZ100HZ001

HZ099

HZ008

HZ146

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

HZ21

HZ039

HZ21B

HZ20A

HZ20B

HZ19A

HZ19C

HZ19B

BFZ100HZ001

HZ099

Figure 5-1. The hydrogeological zones included in the basic hydrogeological structure model. Fracture transmissivities in different classes are shown as coloured discs (oriented fractures) or horizontal squares (unoriented fractures). View towards northeast.

5.1 HZ19 system

Overview

The HZ19 system is characterised by high fracture transmissivities interpreted as the topmost hydrogeological site-scale feature in the ONKALO area. The interpretation of the HZ19 system is based on the occurrence of high fracture transmissivities close to the ground surface and the results of the hydraulic interference tests. The HZ19 system is modelled with three zones, HZ19A, HZ19B, and HZ19C. The geometry of the HZ19 zones has not changed since 2008.

The interpretation of the hydraulic interference tests carried out in drillholes OL-KR14 – -KR18 (Klockars et al. 2006) suggested that compared with sub-horizontal hydraulic connectivity, sub-vertical connections are weaker within the HZ19 system. However, internal hydraulic properties cannot be unambiguously observed, because open drillholes within the ONKALO area spread the pressure effects to all packed-off

64

OL-BFZ019C

OL-BFZ019A

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

OL-BFZ019C

OL-BFZ019A

OL-BFZ019C

OL-BFZ019A

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

sections connected to the HZ19 system. The system with high fracture transmissivities is clearly distinguishable from the underneath sparsely fractured rock due to the low hydraulic conductivity of the rock below the system. The boundary between the system and the rock underneath seems to form a plane dipping gently towards east-southeast. Local hydraulic connections have been interpreted above the modelled HZ19 system in some of the drillholes. Although the HZ19 system is continuous on site-scale, hydraulic properties within the system vary from one drillhole to another indicating a more complex geometry on local-scale.

Compared with the 2008 version, no changes were made in the geometry of the HZ19 zones. Two corresponding brittle deformation zones have been modelled, OL-BFZ019A and -BFZ019C (cf. Chapter 5.2.7) of which only the latter is classified as a site-scale zone. Hydrogeological zones HZ19A, HZ19B, and HZ19C, and corresponding fault zones OL-BFZ019A, and -BFZ19C are visualised in Figure 5-2.

Figure 5-2. Locations of HZ19A (yellow), HZ19C (blue), and HZ19B (green) zones from top to bottom and corresponding brittle deformation zones OL-BFZ019A and -BFZ019C (grey).

65

Intersections in tunnel and shafts

The HZ19 system was intersected by the ONKALO access tunnel at chainages 931.9 – 963.0 m (HZ19A) and 1 045.0 – 1 108.5 m (HZ19C) during November 2005 – June 2006 (Lahti et al. 2009). Two HZ19-intersections have been recognised in the ONKALO access tunnel. The local existence of two intersections is supported by measured fracture transmissivities in nearby shaft drillholes OL-KR24, -KR38, and -KR48 where zones HZ19B and HZ19C have been modelled to the same drillhole sections. Each of the three shafts raise bored so far intersects the HZ19 system. The last of them, ONK-KU3, was raise bored through the system in spring 2009. The tunnel and the shaft intersections were both pregrouted and the current leakage of the HZ19 system into ONKALO is 7 – 9 l/min (Vaittinen et al. 2010a). Leakages within the HZ19 system along the access tunnel are shown in Figure 5-3. Results are based on a mapping campaign carried out in October 2009 (Vaittinen et al. 2010a).

Figure 5-3. Results of water leakage mapping of the tunnel roof and walls carried out in October 2009. Mapping data at the intersection of the HZ19 system between chainages 931.9 – 1 108.5 m (Lahti et al. 2009) are shown. Light blue refers to damp, blue to wet, and red to dripping. No mapped observations in class flowing.

66

5.2 Modelling of HZ19 zones

5.2.1 Background

One HZ19 zone would be enough to represent groundwater flow on site-scale, but in order to characterise the apparently layered system of the groundwater flow paths, three separate sub-horizontal HZ19 zones have been modelled. The zones are modelled to describe 1) anisotropic hydraulic properties in the near surface bedrock caused by sub-horizontal features with high transmissivities and good hydraulic connections, 2) the observed flow and pressure responses during the performed interference tests, and 3) the varying horizontal and vertical dimensions of the HZ19 system, dependent on the location. In addition, distinguished zones enable the modelling of hydrogeochemical variation over depth. Due to the history of the modelling of the HZ19 system, the zones are located in the order of A, C, and B from top to bottom (Figure 5-2).

Site-scale hydrogeological zone R19HY located close to the ground surface was introduced for numerical modelling for the first time in 1999 (Anttila et al. 1999, Löfman 1999). The history of the modelling of the HZ19 zones is given in model Report 2009 (Vaittinen et al. 2009b).

5.2.2 Modelling data and interpretation

Interference tests

The modelling of the HZ19 system was originally based on the interpreted pressure responses of the pumping tests carried out in open drillholes OL-KR7 and -KR8 in 1996 (Niva 1996, Ahokas et al. 2007, and Vaittinen et al. 2008b). The long-term pumping test carried out in drillhole OL-KR24 in the spring 2004 provided new information on the significantly larger continuity for the hydrogeological HZ19 zones (Vaittinen & Ahokas 2005). Due to the open drillholes close to pumped drillhole OL-KR24, the pressure impacts were spread along these drillholes. For this reason, the uncertainty related to the observed responses needs to be taken into account. In addition to pressure responses, flow responses were measured by the PFL-tool (Rouhiainen et al. 2005). Pumping tests have not been carried out since 2008, but the HZ19 system has been pumped for long-term infiltration test purposes (Pitkänen et al. 2008). The main focus is on the overburden and the topmost part of the bedrock down to a few tens of metres, therefore the results offer information on the internal properties of the system on local-scale.

Flow conditions

The results of flow condition measurements carried out since 2008 (cf. Chapter 3.2.5) fit to the modelled HZ19 zones. All of these measured drillholes are modelled to intersect the HZ19 system (Appendix 1).

Pressure responses

Since the 2008 model, new hydraulic observations enabling the assessment of the extent, continuity, and internal properties of the HZ19 system are very limited due to the small number of field activities affecting the head of the system. The strongest disturbance to the head within the system was caused by packer malfunction in drillhole

67

OL-KR22. The consequence of the hydraulic short-circuit along drillhole OL-KR22 was that the head within the HZ19 zones decreased by ca. 2 m and the head within the HZ20 zones increased by ca. 10 m in drillhole OL-KR22 and the effect on the head was visible in all packed-off sections connected to either the HZ19 or HZ20 zones. The effect of the hydraulic short-circuit is visualised with the head diagrams of nearby drillhole OL-KR25, cf. Figure 5-4.

A qualitative analysis of the pressure disturbances caused by packer malfunction in drillhole OL-KR22 was carried out in Vaittinen & Pentti (2011). The first response occurred in the monitoring sections connected to the HZ19 system is visualised in Figure 5-5. The drawdown is determined for the period until groundwater in zone HZ20 reaches zone HZ19 in drillhole OL-KR22. Drawdown typically seems to be lower in monitoring sections connected to the HZ19A zone than in sections connected to zones HZ19B or HZ19C, probably due to the higher transmissivities of the monitoring sections intersecting HZ19A.

The drawdowns determined in the packed-off drillholes (cf. Figure 5-5) are dependent on the distance but drawdowns in drillholes OL-KR12 and -KR15 – -KR18 located north of FDZ are lower than expected, indicating a change in hydraulic connectivity (cf. Chapter 3.2.6, Vaittinen & Pentti 2011). These monitoring sections are located at a distance of ca. 500 m from drillhole OL-KR22 (Figure 5-5). An assessment of the effect of FDZ on hydraulic connections within the HZ19 system is somewhat uncertain due to open drillholes OL-KR14 and -KR42 and the long-term pumping carried out in drillhole OL-KR14 (Pitkänen et al. 2008), although the highly transmissive fractures in -KR14 are interpreted to be mostly related to the HZ19 system.

Based on these interpreted results in packed-off drillholes, no modifications to the geometry of the zones were required.

68

OL-

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69

-10.0

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wdo

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KR04 KR07 KR08 KR09 KR10 KR12 KR15KR16 KR17 KR18 KR22 KR23 KR25 KR27KR29 KR37 KR44 Disturbed HZ19A HZ19B HZ19C

Figure 5-5. Drawdown within the HZ19 system caused by packer malfunction in drillhole OL-KR22.

Geophysics

Compared with other HZs, geophysical methods do not offer as convincing support to the modelling of the HZ19 system. The continuity of the zones is partially supported by a few VSP reflectors and Mise-à-la-masse conduits. The most extensive support is provided by the results of a Mise-à-la-masse survey for the HZ19B zone, cf. Figure 5-6 (Ahokas & Paananen 2010). The explanation for the lack of geophysical anomalies may be related to the location close to the ground surface (unfavourable for geophysical survey geometries) and the geological character of the system.

70

Figure 5-6. Electrical conduits (red) supporting the modelling of zone HZ19B.

Geological setting

The interpreted hydraulic connections are mostly located between zones FDZ and LSZ, i.e. within CTU2 (cf. Figure 4-3). Exceptions include drillholes OL-KR12, -KR14 – -KR18, -KR42, -KR46, and the supplementary shallow B-drillholes located in FDZ or north of FDZ within CTU1 (cf. also Chapter 3.2.6). As described in Section "Pressure responses", drawdowns in drillholes OL-KR12 and -KR15 – -KR18 located north of FDZ are lower than expected, indicating a change in hydraulic connectivity (Vaittinen & Pentti 2011). The orientation is sub-horizontal close to the ONKALO area, but changes into gently dipping in the south and southeast apparently to follow the dip of LSZ. The locations of the drillhole intersections interpreted to characterise the layered HZ19 system are presented in Figure 5-7 with tectonic sub-units.

71

SDZ

FDZ

D4-1

LSZ

SDZ

FDZ

D4-1

LSZ

Figure 5-7. Location of drillhole sections interpreted to characterise the HZ19 system. Red circles refer to zone HZ19A, blue to zone HZ19C, and green to zone HZ19B.

5.2.3 HZ19 system boundaries

Reasoning for the determined boundaries of the HZ19 system is given in the following Sections and the locations of the boundaries are shown in Figure 5-8.

72

Figure 5-8. Locations of the boundaries of the HZ19 zones and the discussed drillholes, view from above (yellow, blue, and green lines refer to zones HZ19A, HZ19C, and HZ19B, respectively).

Towards north The northern boundary of the HZ19 system is modelled between drillholes OL-KR12 and -KR2. Drillholes OL-KR2 and -KR13 were packed-off at the end of 2007, enabling more detailed observations within this area. The effect of nearby open drillholes OL-KR32 and -KR42 on the head level is difficult to assess, but no indications of pressure responses along the HZ19 system are visible in packed-off drillholes OL-KR2 and -KR13 and the zones are not extended there. Supplementary shallow B-drillholes have not been drilled for these drillholes, and the system may therefore occur within the topmost 40 m of bedrock. A hydraulic connection to drillholes OL-KR12 and -KR42 is evaluated as slightly uncertain, because interpretation is based on pressure response during the pumping out of open drillhole OL-KR14 (Klockars et al. 2006).

Zone HZ19C was extended to intersect drillhole OL-KR46, based on the general geometry of the zone and the occurrence of transmissive fractures in 2008. The boundary of the HZ19 system towards north-east was modelled between drillholes OL-KR46 and -KR41. The connection to drillhole OL-KR46 is highly uncertain, because no

73

responses to the several pumpings carried out in drillhole OL-KR46 have been observed in the nearby HZ19 section in drillhole OL-KR11, which strongly responses to field activities affecting the HZ19 system. Therefore, only a weak hydraulic connection can occur.

Towards east The boundary of the HZ19 system is modelled between drillholes OL-KR40 and OL-KR45, based on hydraulic and geophysical Mise-á-la-masse survey data. Although both drillholes are open, head observations during the malfunction period in drillhole OL-KR22 in 2009 as well as during PFL pumping in nearby drillhole OL-KR44 in 2010 support the interpretation. So far, no indications of a hydraulic connection to drillhole OL-KR45 towards southeast have been observed.

Towards south The boundary of the HZ19 system towards south cannot be interpreted on the basis of hydraulic data because hydraulic responses have been observed in each of the southern drillholes. Based on the concept of probably varying hydraulic properties within each tectonic sub-unit, the extent of the HZ19 system towards south was limited in 2008. However, the orientations of boundary zone LSZ and corresponding brittle fault zone OL-BFZ146 have changed from steeply-dipping to moderately dipping from GSM version 1.1 to version 2.0 enabling the HZ19 system to continue on the footwall of LSZ. More information will become available when hydrogeological cross-hole measurements are carried out e.g. in drillholes OL-KR51 and -KR52 intersecting both LSZ and the possible extension of the HZ19 system.

Towards west The boundary towards west is set between drillholes OL-KR4 and -KR1. The zones are located close to the ground surface and hydraulic responses are assumed to be disturbed either by increased fracturing or intersecting local zones. All three zones are modelled to intersect drillhole OL-KR4, but only zone HZ19B is modelled to intersect drillhole OL-KR7.

Sub-vertically Based on head data obtained during the drilling of drillhole OL-KR24 (Vaittinen et al. 2008b) and the OL-KR24 pumping test, it has been interpreted that no site-scale zones occur above the 80 m drillhole depth in drillhole OL-KR24. Monitoring head data support the assumption that modelled zone HZ19A represents the topmost site-scale feature within the central area of the site. Local connections above zone HZ19A have been interpreted in some of the drillholes (cf. Appendix 1, column Local conn.).

The HZ19 system with high fracture transmissivities seems to have a sharp lower boundary. Below the HZ19 zones, only a few transmissive fractures with a transmissivity higher than 1·10-6 m2/s occur down to the HZ20 system.

5.2.4 Zone HZ19A

Zone HZ19A describes the topmost sub-horizontal hydraulic connections covering a larger area, which explains the hydraulic pressure responses observed in drillholes OL-

74

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

KR15B � -KR18B towards north and the flow responses observed in drillholes OL-KR8 and -KR27 towards south during the OL-KR24 pumping test.

The location of the ground intersection could not be determined for zone HZ19A or for corresponding brittle deformation zone OL-BFZ019A. For numerical modelling purposes, the topmost boundary of the zone is raised onto the ground surface. Due to the almost horizontal orientation, linear extrapolation would have moved the ground intersection too far towards west.

The average orientation of the zone is 144/5° in terms of dip direction and dip. The zone and the transmissivities are visualised in Figure 5-9. The drillhole depth intervals for the zone and for the transmissivity depth range, the defining method for the transmissivity depth range (cf. Chapter 2.4.1), and the drillhole-specific transmissivities of zone HZ19A are shown in Table 5-2. The transmissivities are also visualised in Figure 5-10, which shows values both in 2008 and in 2010. Although the geometry of the zone has not been modified, drillhole-specific transmissivity values have changed due to the definition applied for the transmissivity depth range.

Figure 5-9. Zones HZ19A (yellow) and OL-BFZ019A, and fracture transmissivities, view towards east.

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Table 5-2. Drillhole depth intervals for the zone and the transmissivity (T) depth ranges, defining method applied for T depth ranges (cf. Chapter 2.4.1), and drillhole specific transmissivities of zone HZ19A.

HZ19A Zone intersection, m T depth range, m T, m2/s log T Note OL-KR04 80.5 84.1 80.5 84.1 3 1.7E-05 -4.8 OL-KR08 80.6 83.3 76.7 83.3 3 2.7E-05 -4.6 OL-KR10 39.8 41.8 39.8 41.8 3 2.6E-07 -6.6 OL-KR14 50.0 52.0 47.5 56.0 1 1.6E-04 -3.8 OL-KR15B 19.1 25.1 19.1 25.1 3 1.7E-05 -4.8 OL-KR16B 17.0 19.0 17.0 19.0 3 1.4E-06 -5.8 OL-KR17B 8.0 10.0 8.0 10.0 3 1.0E-05 -5.0 OL-KR18B 31.3 33.3 31.3 33.3 3 1.7E-05 -4.8 OL-KR22 96.1 102.7 89.2 102.7 3 1.5E-05 -4.8 OL-KR23 88.7 94.7 88.7 94.7 3 2.0E-06 -5.7 OL-KR24 93.0 95.3 93.0 95.3 3 3.2E-05 -4.5 OL-KR25 58.6 64.6 58.6 64.6 3 4.0E-05 -4.4 OL-KR27 129.0 133.0 129.0 133.0 3 6.0E-07 -6.2 OL-KR28 134.0 140.0 134.0 140.0 3 4.8E-07 -6.3 OL-KR29 62.0 64.0 62.0 64.0 3 1.1E-07 -7.0 OL-KR30 50.7 54.7 50.7 54.7 3 4.1E-05 -4.4 OL-KR31 101.4 109.4 101.4 109.4 3 1.1E-06 -6.0 OL-KR34 60.7 79.3 60.7 82.3 3 7.2E-05 -4.1 OL-KR35 69.1 78.8 69.1 78.8 3 5.4E-05 -4.3 OL-KR35* 89.6 96.9 89.6 96.9 3 2.3E-05 -4.6 OL-KR36 84.5 95.4 84.5 95.4 3 5.7E-05 -4.2 OL-KR37 122.8 125.8 112.0 126.0 1 1.6E-05 -4.8 OL-KR38 87.2 89.6 86.2 89.6 3 5.1E-05 -4.3 OL-KR44 99.2 107.1 89.1 107.1 3 3.4E-05 -4.5 OL-KR48 95.1 97.1 95.1 97.1 3 1.5E-05 -4.8 ONK-PH04 84.0 86.0 84.0 86.0 3 1.3E-05 -4.9 *Not used for zone modelling

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HZ19A

KR04KR08

KR10KR14

KR15BKR16B

KR17B

KR18B

KR22

KR23 KR24

KR25

KR27

KR28

KR29

KR30

KR31

KR34KR35

KR36

KR37

KR38

KR44

KR48

PH04PH04

KR48

KR44

KR38

KR37

KR36

KR35KR34

KR31

KR30

KR29

KR28

KR27

KR25

KR24KR23

KR22

KR18B

KR17B

KR16BKR15B

KR14KR10

KR08KR04

0

50

100

150

-10 -9 -8 -7 -6 -5 -4 -3log T (m2/s)

Dep

th (m

)

T 2008T 2010

Figure 5-10. Measured transmissivities of zone HZ19A. T 2008 refers to the transmissivities of the 2008 model and T 2010 to the current version.

5.2.5 Zone HZ19C

Zone HZ19C describes the most extensive sub-horizontal connections within the HZ19 system explaining the hydraulic pressure responses observed in drillholes OL-KR9, -KR11, and -KR15 � -KR18 towards north and east, and the flow responses observed in drillholes OL-KR8 and -KR27 towards south during the OL-KR24 pumping test. Compared with the size of zone HZ19A, drillholes OL-KR9, -KR11, -KR40, and -KR46 are included in zone HZ19C but not in zone HZ19A.

The location of the ground intersection could not be determined for zone HZ19C or for corresponding brittle deformation zone OL-BFZ019C. For numerical modelling purposes, the topmost boundary of the zone is raised onto the ground surface. Due to the almost horizontal orientation, linear extrapolation would have moved the ground intersection too far towards west.

77

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

The average orientation of the zone is 139/8° in terms of dip direction and dip. The zone and the transmissivities are visualised in Figure 5-11. The drillhole depth intervals for the zone and for the transmissivity depth range, the defining method for the transmissivity depth range (cf. Chapter 2.4.1), and the drillhole-specific transmissivities of zone HZ19C are shown in Table 5-3. The transmissivities are also visualised in Figure 5-12, which shows values both in 2008 and in 2010. Although the geometry of the zone has not been modified, drillhole specific transmissivity values have changed due to the definition applied for the transmissivity depth range.

Figure 5-11. Zones HZ19C (blue) and OL-BFZ019C, and fracture transmissivities, view towards northeast.

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Table 5-3. Drillhole depth intervals for the zone and the transmissivity (T) depth ranges, defining method applied for T depth ranges (cf. Chapter 2.4.1), and drillhole specific transmissivities of zone HZ19C.

HZ19C Zone intersection, m T depth range, m T, m2/s log T Note OL-KR04 115.0 117.8 98.5 126.5 1 3.7E-05 -4.4 OL-KR08 106.0 114.8 105.0 123.4 3 2.1E-05 -4.7 OL-KR09 146.3 151.1 146.3 151.1 3 9.1E-06 -5.0 OL-KR10 60.6 64.8 60.6 64.8 3 2.5E-08 -7.6 OL-KR11 121.8 123.8 104.0 144.0 1 4.4E-06 -5.4 OL-KR12 42.0 46.5 42.0 46.5 3 2.3E-06 -5.6 OL-KR14 79.0 81.0 79.0 81.0 3 4.6E-06 -5.3 OL-KR15 57.6 59.6 55.7 64.5 3 6.8E-06 -5.2 OL-KR16 47.9 49.9 47.9 49.9 3 7.0E-06 -5.2 OL-KR17 49.8 51.8 49.8 51.8 3 3.0E-06 -5.5 OL-KR18 50.4 52.4 50.4 52.4 3 6.0E-06 -5.2 OL-KR22 108.3 113.2 108.3 113.2 3 1.1E-04 -4.0 OL-KR23 135.2 137.2 135.2 137.2 3 1.5E-05 -4.8 OL-KR24 114.5 116.8 112.5 116.5 1 1.9E-05 -4.7 1) OL-KR25* 70.1 84.9 70.1 84.9 3 1.6E-05 -4.8 OL-KR25 94.6 97.5 92.3 97.5 3 2.8E-05 -4.6 OL-KR27 207.0 211.0 207.0 211.0 3 2.8E-07 -6.5 OL-KR28 155.4 159.4 143.2 159.7 3 4.8E-05 -4.3 OL-KR29 96.0 98.0 96.0 98.0 3 2.9E-07 -6.5 OL-KR30 81.6 83.6 80.0 92.5 1 3.9E-06 -5.4 OL-KR31 143.4 145.4 143.4 145.4 3 6.9E-06 -5.2 OL-KR36 153.9 156.9 152.0 165.0 1 6.1E-05 -4.2 OL-KR37 171.0 175.1 171.0 175.1 3 1.2E-05 -4.9 OL-KR38 119.6 122.5 116.9 123.1 3 1.9E-05 -4.7 1) OL-KR40 284.0 284.5 266.0 287.0 1 9.4E-07 -6.0 OL-KR42 83.6 89.6 83.6 89.6 3 2.3E-06 -5.6 OL-KR44 117.1 125.2 117.1 125.2 3 2.1E-06 -5.7 OL-KR46 84.3 86.3 84.3 86.3 3 2.2E-08 -7.7 OL-KR48 106.2 108.2 106.2 108.2 3 4.3E-06 -5.4 1) ONK-PH05 56.0 58.0 56.0 60.0 1 3.0E-05 -4.5 *Not used for zone modelling 1) Measured T value divided into two zones

79

HZ19C

KR04

KR08

KR09

KR10

KR11

KR12

KR14

KR15

KR16

KR17KR18

KR22

KR23

KR24

KR25

KR27

KR28

KR29

KR30

KR31KR36

KR37

KR38

KR40

KR42

KR44

KR46

KR48

PH05PH05

KR48

KR46

KR44

KR42

KR40

KR38

KR37

KR36

KR31

KR30KR29

KR28

KR27

KR25

KR23

KR22

KR18KR17

KR16

KR15

KR14

KR12

KR11

KR10

KR09

KR08

KR04

0

100

200

300

-10 -9 -8 -7 -6 -5 -4 -3log T (m2/s)

Dep

th (m

)

T 2008T 2010

KR24

Figure 5-12. Measured transmissivities of zone HZ19C. T 2008 refers to the transmissivities of the 2008 model and T 2010 to the current version.

5.2.6 Zone HZ19B

Zone HZ19B describes hydraulic connections, which cannot be explained with zones HZ19A or HZ19C, i.e. the hydraulic connections between drillholes OL-KR7 and -KR4, drillholes -KR8 and -KR4, drillholes -KR24 and -KR8, and drillholes -KR24 and -KR27 observed during the performed pumping tests. Zones HZ19B and HZ19C have been modelled to the same drillhole sections in shaft drillholes OL-KR24, -KR38, and -KR48 due to the varying occurrence of transmissive fractures within the system. These drillholes are located less than 50 m apart.

The average orientation of the zone is 151/16° in terms of dip direction and dip. The zone and the transmissivities are visualised in Figure 5-13. The drillhole depth intervals for the zone and for the transmissivity depth range, the defining method for the transmissivity depth range (cf. Chapter 2.4.1), and the drillhole specific transmissivities of zone HZ19B are shown in Table 5-4 and the transmissivities are also visualised in Figure 5-14. Although the geometry of the zone has not been modified, the drillhole

80

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

specific transmissivity values have changed due to the definition applied for the transmissivity depth range. The transmissivity in drillhole OL-KR37 was erroneous in Vaittinen et al. (2009).

Figure 5-13. Zone HZ19B and fracture transmissivities, view towards northeast.

81

HZ19B

PH05

KR48

KR38

KR37

KR31

KR28

KR27

KR25

KR24

KR23

KR22

KR08

KR07

KR04

PH05

KR48

KR38

KR37

KR31KR28

KR27

KR25KR24

KR23

KR08

KR07

KR04

0

100

200

300

-10 -9 -8 -7 -6 -5 -4 -3log T (m2/s)

Dep

th (m

)

T 2008T 2010

KR22

Table 5-4. Drillhole depth intervals for the zone and the transmissivity (T) depth ranges, defining method applied for T depth ranges (cf. Chapter 2.4.1), and drillhole specific transmissivities of zone HZ19B.

HZ19B Zone intersection, m T depth range, m T, m2/s log T Note OL-KR04 140.6 142.6 140.6 142.6 3 9.0E-07 -6.0 OL-KR07 46.9 48.8 46.9 48.8 3 4.2E-07 -6.4 OL-KR08 249.1 255.9 249.1 256.5 3 6.3E-06 -5.2 OL-KR22 146.9 152.7 136.5 162.5 1 1.3E-04 -3.9 OL-KR23* 175.0 185.5 175.0 185.5 1 5.7E-06 -5.2 OL-KR23 192.8 197.0 192.5 209.5 1 1.6E-05 -4.8 OL-KR24 114.5 116.8 112.5 116.5 1 1.9E-05 -4.7 1) OL-KR25 123.3 125.3 112.5 125.5 1 3.5E-06 -5.5 OL-KR27 256.8 262.7 256.6 262.7 3 3.4E-06 -5.5 OL-KR28 170.0 180.2 161 189 1 1.8E-06 -5.8 1) OL-KR31 174.0 176.0 163 179.5 1 2.2E-05 -4.7 OL-KR37 195.2 197.2 195.2 197.2 3 1.6E-07 -6.8 OL-KR38 119.6 122.5 116.9 123.1 3 1.9E-05 -4.7 1) OL-KR48 106.2 108.2 106.2 108.2 3 4.3E-06 -5.4 1) ONK-PH05 172.0 176.0 172.0 176.0 3 1.6E-06 -5.8 *Not used for zone modelling 1) Measured T value divided into two zones

Figure 5-14. Measured transmissivities of zone HZ19B. T 2008 refers to the transmissivities of the 2008 model and T 2010 to the current version. Circle refers to erroneous value.

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5.2.7 Corresponding brittle fault zones

Site-scale brittle fault zone OL-BFZ019C of GSM version 2.0 (Aaltonen et al. 2010) is a gently dipping thrust fault with an approximate dip of ca. 10 – 25° towards south-southeast. The fault is located a few tens of metres beneath sub-parallel repository-scale fault zone OL-BFZ019A (cf. Figure 5-2). The modelled zone has 21 drillhole intersections, and it is also observed in the ONKALO access tunnel. In 10 drillholes, the fault is fixed to a mapped brittle fault or a brittle joint intersection and in 4 holes to a fracture structured RiIII section or core loss sections based on the general geometry and/or Mise-á-la-masse results. Clear geological indications are lacking in three drillholes (OL-KR4, -KR10, and -KR14), and the zone is modelled to intersect these locations according to the Mise-á-la-masse results or just according to the general geometry. The fault is possibly segmented so that it does not intersect these drillholes or the fault core is so poorly developed that it has not been recognised in structural geological drill core mapping. Compared with HZ019C, BFZ019C has not been modelled to drillholes OL-KR11, -KR12, -KR29, -KR37, -KR44, -KR46, and -KR48. With respect to GSM v. 1.1 (Posiva 2009), drillhole intersections in OL-KR9, -KR11 and -KR44 have been removed due to a re-analysis of the fractures in the core zone and the geometry has been changed slightly near OL-KR45 to better fit to the OL-KR45 intersection (Aaltonen et al. 2010). Based on the SAMPO Gefinex results, the fault zone is extended to the southeast from the densely drilled area, although only weak seismic indications are related to this extension in the 2007 3D reflection survey results.

The thickness of the fault core is approximately 0.1 – 1.4 m and the core zone is frequently hydraulically conducting. Fracture-controlled kaolinitisation, illitisation and sulphidisation are typical of the zone although illitisation is occasionally also pervasive. One feature common to almost all the drill core intersections is the occurrence of old, welded ("healed"), calcite-filled fractures, which have later been reactivated. In the ONKALO access tunnel, the zone has been modelled to a brittle fault intersection in chainage 1 045 m. The core of the zone therein is 10-20 cm wide and consists of a main fault that can be followed in both tunnel walls. The influence zone is over 5 m wide, consisting of conjugate fractures. The main fracture was highly water conductive before grouting. There are many other long and sub-horizontal fractures in the zone and several shorter vertical fractures that join the horizontal ones.

Compared with hydrogeological zone HZ19C, a striking difference is the limited extent of OL-BFZ019C in the northeast – southwest direction. Hydrogeological zone HZ19C continues to the northeast to drillhole OL-KR11, where there is a clear brittle fault intersection. However, OL-BFZ019C, which is fixed to OL-KR40, cannot be connected to OL-KR11, because of lack of any supportive structural evidence in drillholes OL-KR9, -KR41, -KR44 and -KR46 between -KR40 and -KR11. To the southwest, HZ19C has been fixed to drillhole OL-KR29, which is not possible in case of OL-BFZ019C, on the basis of lack of supportive structural geological data therein.

From a structural geological point of view, brittle fault zone OL-BFZ019C and the brittle fault intersection in OL-KR11 included in HZ019C seem to be two separate fault zones. They could be mutually connected via individual water-conductive fractures (fault splays?), which do not show in the structural geological model. Moreover, the status of OL-BFZ019C as a uniform site-scale zone can be considered questionable. As

83

explained earlier, many of the drillhole intersections connected to OL-BFZ019C are lacking in proper fault intersections. This may indicate that the fault zone is not uniform but segmented into several separate fault zones, which may be connected via step-over zones. As discussed in Chapter 4, a failure in the modelling due to erroneous data or lack of data is always a possibility.

OL-BFZ019C has been fixed to OL-KR45, while in case of HZ19C no hydraulic connection to OL-KR45 has been observed. The continuation of OL-BFZ019C to drillhole OL-KR45 is based on SAMPO Gefinex results and weak seismic indications in the 2007 3D reflection survey results, and can be considered rather uncertain.

Repository-scale brittle fault zone OL-BFZ019A is a gently dipping thrust fault with an approximate dip of ca. 15 degrees towards SE. The core of the fault is 0.1 – 4 m thick with increased fracturing and occasional slickenside fractures. The fault is located just some tens of metres above fault OL-BFZ019C and is sub-parallel to it. The fault is intersected by 20 drillholes. The core is characterised by brittle fault intersections or RiIII-IV-sections in 14 drillholes. In drillholes OL-KR28 and -KR35, significant geological evidence is lacking, however the fault is delineated to them according to its general geometry and geophysical results. In most drillholes, the core of the fault is also hydraulically conducting. Geophysically, the fault can be observed frequently as a P-wave minimum and an electric conductor. The geometry of the fault is based mainly on combining Mise-à-la-masse and VSP results with geological observations in the drillholes. Predominantly fracture-controlled kaolinisation, illitisation and sulphidisation are observed along the zone, although alteration is sporadically also pervasive.

In the ONKALO tunnel, the fault can be observed at the chainage of ca. 950 – 963 m, related to a long brittle fault intersection, located at 931.90 – 963.00 m. The intersection angle between the fault and the tunnel is rather oblique. The fault intersection is undulating, slickensided and contains 3-40 cm thick fillings of chlorite, clay, pyrite, calcite, graphite, and kaolinite. In the thickest parts, the filling contains some broken rock fragments and thick clay fillings. The fault is also hydraulically conductive.

Compared with HZ019A, BFZ019A does not exist in drillholes OL-KR8, -KR10, -KR14, -KR15B, – -KR18B, -KR27, -KR29, -KR31, and -KR44. There is no structural geological evidence of the continuation of the fault zone to these drillholes.

5.2.8 Uncertainties

Due to the sharp pressure responses during the OL-KR24 pumping test, it is obvious that the extent of the HZ19 zones is limited and they form a restricted system. E.g. drawdown was 0.41 m in drillhole OL-KR11 at a distance of about 1 000 m during the pumping test carried out in drillhole OL-KR24. However, the horizontal extent towards north-east, south, and south-west is based on expert judgement. The boundary towards north and north-west can be estimated.

Zone HZ19C is modelled to intersect drillhole OL-KR46, but the intersection is not as certain as the other intersections, because it is included in zone HZ19C based on general geometry and fitting transmissive fractures.

84

Despite the location close to the ground surface and some indicative fracture observations in the investigation trenches (Ahokas et al. 2007), no exact surface intersections could be determined. The ground surface intersections of zones HZ19A and HZ19C are therefore technical solutions for numerical modelling purposes.

Alternative interpretation

The geometry of the HZ19 system was not changed and the interpretation of hydraulic flow and pressure responses supported the modelled hydraulic connections, but indications of an alternative geometry have been observed. A noteworthy observation is related to hydraulic connections from ONKALO towards drillhole OL-KR11. When both drillholes OL-KR9 and -KR11 were packed-off, head on the monitoring levels intersected by the HZ19 system, L5 and L7, respectively, responded similarly to drawdowns that occurred within the system despite the rather long distances. The distance between these monitoring sections is ca. 500 m and distances between the HZ19 tunnel intersection and sections are in the order of magnitude of 750 m (OL-KR9) and 1 000 m (OL-KR11).

It is possible that instead of the currently modelled planar connection, the flow route from drillhole OL-KR9 to -KR11 is channelled along potential SSW-NNE striking brittle structures associated with the D4-1 shear zone (Chapter 4.1), cf. Figure 5-15. This assumption is supported by the monitored head and field activities carried out in nearby drillholes OL-KR41 and -KR46. Because e.g. pumping in these drillholes has not caused responses in the HZ19 intersection in drillhole OL-KR11, only a weak hydraulic connection can occur. Taking into account the statistical character of the ductile deformation model, the HZ19 intersection in drillhole OL-KR11 is likely to be within the range of the D4-1 formation and drillholes OL-KR41 and -KR46 within modelled zones FDZ or SDZ.

A hydraulic connection between drillholes OL-KR11 and -KR46 occurs below the HZ19 intersection at depths of 212.1 – 217.1 m and 132.3 – 136.2 m, respectively (cf. Chapter 6). These intersections are both located within SDZ.

A possible continuity of the HZ19 system is related to the hydraulic properties of the D4-1 feature. Electrical Mise-à-la-masse conduits suggest hydraulic continuity on Olkiluoto Island. Electrical conduits and the ductile sub-unit D4-1 coincide with each other well, suggesting hydraulic connections, too. However, no brittle fault or joint zones have been modelled within the ductile D4-1 zone so far.

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SDZ

FDZ

D4-1HZ19C

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

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T, m ²/s>1E -8>1E -7>1E -6>1E -5

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T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

Figure 5-15. Possible groundwater flow connection between drillholes OL-KR9 and -KR11 following the ductile D4-1 feature. Mise-à-la-masse conduits following D4-1 feature are also shown.

5.3 HZ20 system

Overview

The HZ20 system is considered the most important hydrogeological feature to be intersected by the ONKALO access tunnel and shafts. It is characterised by high fracture transmissivities and good hydraulic connections and it reaches the planned repository depth. The modelling of the system is based on several pumping tests carried out since 1992 (Ylinen et al. 1992, Niva 1996, Jääskeläinen 1998, Vaittinen & Ahokas 2005). The results of the OL-KR4 pumping test carried out in 1998 (Jääskeläinen 1998) provided information on the extent of hydraulic connections, and drillholes drilled since 1998 have confirmed the location of the HZ20 system in the central tectonic unit and given the approximate boundaries.

The HZ20 system is modelled with two zones describing the upper (HZ20A) and the lower (HZ20B) surfaces of the interpreted direct hydraulic connections within the system. The objective is to provide a consistent description and model of the system for numerical modelling purposes, i.e. interpreted direct hydraulic connections characterised by high fracture transmissivities are modelled as zones and weaker

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connections to drillhole sections with moderate or low fracture transmissivities are described as local features or internal properties.

Modelled zones HZ20A and HZ20B and corresponding brittle deformation zones OL-BFZ020A and -BFZ020B are visualised in Figure 5-16.

Intersections in tunnel and shafts

The HZ20 system was intersected by underground facilities for the first time when the ONKALO access tunnel was excavated through the HZ20 system during July 2008 – January 2009. Based on geological mapping data, the system was met at chainages 3 157 –3 182 m (HZ20A) and 3 286 – 3 325 m (HZ20B) in the ONKALO access tunnel.

The excavation of the ONKALO access tunnel through the HZ20 system was carried out using the following procedure. First, a pilot hole was drilled and geological mapping of the core as well as both geophysical and hydrological measurements were performed. Next, four probe holes, TRA, -B, -C, and -D, usually located inside the tunnel profile, were bored. The probe holes were characterised through inflow water measurement, water loss measurement, and flow log measurement, and if the grouting criterion was fulfilled, grouting holes were bored. The grouting result was verified by means of a control hole. Pilot holes, probe holes, and grouting holes are visualised for zone HZ20A in Figure 5-17 and for zone HZ20B in Figure 5-18. Fracture transmissivities and measured inflows are also presented, respectively. Excavation caused temporary inflows into the tunnel and drawdowns within the HZ20 system. The highest measured inflow of 138 l/min occurred along probe holes at chainage 3 140 m, and the strongest observed drawdown caused by inflow was of the order of magnitude of 15 m (Vaittinen et al. 2010b). In most cases temporary inflows lasted a few days.

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OL-BFZ020A

OL-BFZ020B

T, m ²/s>1E -8>1E -7>1E -6>1E -5

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T, m ²/s>1E -8>1E -7>1E -6>1E -5

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T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

Figure 5-16. Locations of the HZ20A (red), and HZ20B (blue) zones and corresponding brittle deformation zones OL-BFZ020A (upper, large one) and OL-BFZ020B (lower).

Based on leakages measured by permanent measuring weirs located along the tunnel, leakage related to the HZ20 system seems to have stabilised to a inflow of 6 – 7 l/min and drawdown was approximately 10 m in the spring 2009. Leakages within the HZ20 system along the access tunnel are shown in Figure 5-19. The results are based on a mapping campaign carried out in October 2009. (Vaittinen et al. 2010a).

The construction of the shafts through the system started after tunnel penetration. Pre-grouting holes along shafts ONK-KU1 – -KU3 have been drilled through it, but none of the shafts have been raise bored, so far. The grouting was carried out in four stages within each shaft. Open grouting holes caused inflows and drawdowns similar to those that occurred during the excavation of the tunnel through the system.

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Figure 5-17. Location of pilot hole ONK-PH8, probe holes (upper left), and grouting holes (upper right) through modelled zone HZ20A (the zone in front of the tunnel is removed), and the length of holes and inflow during drilling (lower). Boreholes within grey sections (lower) have not been measured.

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Figure 5-18. Location of pilot hole ONK-PH9, probe holes (upper left), and grouting holes (upper right) through modelled zone HZ20B (the zone in front of the tunnel is removed), and the length of holes and inflow during drilling (lower). Boreholes within grey sections (lower) have not been measured.

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Figure 5-19. Results of the water leakage mapping of the tunnel roof and walls carried out in October 2009 (Vaittinen et al. 2010a), mapping data at the intersection of the HZ20 system between chainages 3 157 – 3 325 m. Light blue refers to damp, blue to wet, and red to dripping. No mapped observations in class flowing.


5.4.1 Background

Sub-horizontal hydrogeological zones were for the first time studied in ground water flow modelling as alternative interpretations of field investigations in 1996 (according to Ahokas in Löfman 1996). Site-scale hydrogeological zone R20HY was introduced in 1999 (Anttila et al. 1999, Löfman 1999).

In the 2006 hydrogeological model (Ahokas et al. 2007), the HZ20 system consisted of zones HZ20A, HZ20AE, HZ20B, and HZ20B_ALT, with HZ20A describing the upper surface of the system and HZ20B_ALT the lower surface. Zone HZ20B connected high transmissivities between the upper and the lower surface and thereby characterised the internal hydraulic properties of the system. However, hydraulic properties vary from one drillhole to another and zones HZ20B and HZ20B_ALT were therefore partly modelled to the same drillhole sections. The description of the HZ20 system was simplified in 2008 (Vaittinen et al. 2009b) to contain zones HZ20A and HZ20B, describing the upper and lower surfaces of the interpreted direct hydraulic connections between the drillholes. Within the northwest area, only zone HZ20A was modelled due to the diminishing thickness of the HZ20 system. The aim of the simplification was to describe the HZ20 system more from the site-scale point of view for numerical modelling purposes.

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The more detailed history of the modelling of the HZ20 zones is given in model Report 2009 (Vaittinen et al. 2009b).


The modelling of the HZ20 system is based on the results of pumping tests carried out since 1992. In addition, the geometry of the HZ20 system is strongly supported by geophysical Mise-à-la-masse and Sampo Gefinex results, and several VSP reflectors. Also, the 3D seismic reflectors as well as seismic HIRE anomalies support the interpretation.

Interference tests

The first indications of the system were obtained in the OL-KR1 pumping test in 1992 (Ylinen et al. 1992) and in the OL-KR7 pumping test in 1995 (Niva 1996). Originally the modelling of the HZ20 system was based on the results of the OL-KR4 pumping test carried out in 1998 (Jääskeläinen 1998). The long-term pumping test carried out in drillhole OL-KR24 during the spring 2004 supported the earlier concept of the hydrogeological HZ20 system (Vaittinen & Ahokas 2005).

The pumping test in drillhole OL-KR4 was carried out in the packed-of section at a depth of 293.5-375.2 m during 17.2.-3.3.1998 (Jääskeläinen 1998). The pumped section covered the entire HZ20 intersection. All the deep drillholes were packed-off, except for OL-KR6. The average pumping rate was 17 l/min and the drawdown was about 17.8 m in the pumped section and about 0.3 m above the pumped section. Very strong responses, up to 9.5 m were observed. A 3D visualisation of the interpreted hydraulic connections (Jääskeläinen 1998, Vaittinen et al. 2008) is shown in Figure 5-20.

The higher than expected drawdowns in the OL-KR4 and -KR24 pumping tests based on the infinite radial flow field along the confined aquifer support the limited extension (or limited connection to boundary zones) of the HZ20 zones (Ahokas et al. 2007).

Similar interference tests have not been carried out since the 2008 version. Summaries of the aforesaid pumping tests are presented in Vaittinen et al. (2008, 2009b).

Flow conditions

The flow condition is measured with the PFL-tool in selected open drillholes as part of the monitoring programme, cf. Chapter 3.2.5. Drillholes OL-KR4, -KR22, -KR27, and -KR40 intersect the HZ20 system in which the first three drillholes are currently packed-off. The observed flow conditions coincide with the interpretation of the HZ20 system. Both flow and head changes in open drillhole OL-KR40 strongly support the modelling of the HZ20 system. The inflows observed at the depths of 607 m (358 ml/h) and 611 m (223 ml/h) in 2006 changed in 2009 to outflows of 7 690 ml/h and 4 070 ml/h, respectively. The heads measured with the PFL-tool have decreased from 2 m.a.s.l. to -13 and -14 m.a.s.l. at the same depths (Vaittinen et al. 2010a). The changes are caused by a decrease in the head within the HZ20 system due to leakage into ONKALO.

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Drawdown, m0 - 11 - 22 - 33 - 44 - 55 - 66 - 77 - 8

Observation section8 - 9

Pumped section

Drawdown, m0 - 11 - 22 - 33 - 44 - 55 - 66 - 77 - 8


Pumped section

Drawdown, m0 - 11 - 22 - 33 - 44 - 55 - 66 - 77 - 8


Pumped section

Figure 5-20. Observed packed-off sections and interpreted drawdowns during pumping tests carried out in drillhole OL-KR4 in 1998. Uncertain connections are shown with a dash line.

Pressure responses

The hydrogeological analysis of hydraulic effects during the excavation of the access tunnel provided detailed information on the HZ20 system. A summary of the analysis is given in following Sections. According to the results of the analysis, zone HZ20A was extended to drillholes OL-KR16 and -KR27 (cf. Figure 5-21). As reference information, the head of monitoring section OL-KR25 L3, located within zone HZ20A close to ONKALO, is visualised.

The head diagrams of drillhole OL-KR8 during the packing-off period in 2003 (Vaittinen et al. 2008) were reinterpreted. At that time the drillhole was packed-off for the monitoring of pressure responses caused by the drilling of drillhole OL-KR24 over three weeks. A minor drawdown caused by pumping for groundwater sampling purposes in nearby open drillhole OL-KR22 was interpreted at the 440.2 – 460.0 m section, fitting well to the geometry of zone HZ20A (cf. Figure 5-21). That section has not been packed-off since 2003. Because the transmissivity of the HZ20 system seems to decrease towards southeast, possibly due to increasing depth e.g. in nearby drillholes OL-KR23, -KR27, and -KR40, both the transmissivity of the section in drillhole OL-KR8 and the geometry fit to the HZ20A zone.

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3317330332633213317031403121

HZ20BHZ20A

-15-14-13-12-11-10

-9-8-7-6-5-4-3-2-101234567

1.7.08 31.7.08 31.8.08 1.10.08 31.10.08 1.12.08 1.1.09 31.1.09

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.l.

KR08 L1 542-567 KR08 L2 440.2-462

Figure 5-21. Head diagrams of monitoring sections interpreted to intersect zone HZ20A in drillholes OL-KR16 and -KR27 (upper) and OL-KR8 (lower). Drawdown in drillhole OL-KR8 is caused by the pumping out of drillhole OL-KR22. Zone HZ20B is modelled to the KR08 L1 monitoring section.

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Excavation of tunnel through zones The hydrogeological analysis of hydraulic effects during the excavation of the access tunnel provided more detailed information on the HZ20 system (Vaittinen et al. 2010b). At the time tunnel excavation started in 2004, most of the nearest drillholes were still open. In order to ensure improved conditions to interpret the possible hydrogeological responses of the ONKALO construction process, the drillholes were equipped with packers to isolate their intersections with hydrogeological zones (cf. Figure 3-13). The results of the analysed observations supported the restricted extent of the hydrogeological HZ20 system. Contrary to other drillholes, where the upper surface (HZ20A) and the lower surface (HZ20B) are isolated, the HZ20 system is located within one monitoring section in drillhole OL-KR7 causing hydraulic short-circuit within the system. Therefore only indicative information on internal hydraulic properties is available.

A continuous leakage of 6 – 7 l/min in the HZ20 system into the access tunnel enabled for the first time observation of weak hydraulic connections to the system. To characterise the different kind of hydraulic connections, the monitoring sections were divided into three groups primarily based on the transmissivity of the section, the strength of drawdown, and the recovery of head. The groups were a) direct hydraulic connections, b) connections through smaller-scale hydrogeological zones, and c) connections through fractures with low transmissivity. The same division has been applied in the following paragraphs to describe the interpreted hydraulic connections.

The monitoring sections and the corresponding head diagrams of each group are shown in Figure 5-22, Figure 5-24, and Figure 5-25. Hydraulic connections are presented in 3D visualisations as tubes starting from the intersection of zone HZ20A in the access tunnel. The colours of the tubes and monitoring sections refer to the transmissivity of the sections. To illustrate the location of the connections, current versions of the HZ20A and HZ20B zones are included in the visualisations. The drawdowns in the head diagrams show temporary inflows caused by the drilling of pilot holes ONK-PH8 and -PH9 and the boring of probe holes and grouting holes through the HZ20A and HZ20B zones.

Head level within the HZ20 zones started to decrease in June 2008, when the last nearby drillhole OL-KR4 was packed-off and the HZ20 system was isolated from the HZ19 system. The decrease was still ongoing, when the drilling of pilot hole ONK-PH8 started an inflow. The head level of the HZ20 system before the penetration is therefore not known precisely. After excavation through zone HZ20A in October 2008, the average head level close to ONKALO was ca. 1 – 2 m.a.s.l. and after excavation through zone HZ20B in February 2009 ca. -4 – -3 m.a.s.l. The strongest temporary drawdowns were related to the drilling of pilot hole ONK-PH8, the boring of grouting holes at chainages 3 121 m, 3 140 m, and 3 145 m, the drilling of pilot hole ONK-PH9, and the boring of grouting holes at chainages 3 263 m, 3 273 m, 3 288 m, and 3 307 m.

Direct hydraulic connections The interpreted direct hydraulic connections characterise the upper and lower surfaces of the HZ20 system and are used to model the HZ20A and HZ20B zones, respectively. The interpreted direct hydraulic connections, modelled zones, and corresponding head diagrams are visualised in Figure 5-22. This kind of a connection is typically located in

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a drillhole section with increased fracturing and high fracture transmissivities. Head diagrams show strong and sharp pressure responses with quick recovery.

According to the interpretation of responses during tunnel excavation, two drillholes packed-off after the previous 2008 model version contain monitoring sections characterising zone HZ20A: OL-KR16 L1 and -KR27 L1. Also, a change in the hydraulic connectivity from the central HZ20 area to the northwest area was interpreted (Vaittinen et al. 2010b). An indication of the change is visible in Figure 5-23, where the section drawdown is plotted as a function of distance between the HZ20A tunnel intersection and each monitoring section. Drawdown is lower in drillholes OL-KR1, -KR5, -KR20, and -KR39 although there is no significant difference in distances. When the transient Theis solution was applied to the drawdown caused by inflow during the drilling of pilot hole ONK-PH8 through zone HZ20A, a change was also then interpreted in the hydraulic properties affecting the pressure field.

When matching the Theis solution (transmissivity, distance, and drawdown), the aforementioned drillholes differed from the drillholes within the central area by clearly higher transmissivity values compared with measured transmissivities. The measured transmissivities are of the same order of magnitude in both areas. The transient time series of the head since the beginning of the maximum inflow of 20 l/min through 14 days were applied in the analysis. Inflow was interrupted due to the packing-off of the pilot hole during a two-day drilling break. Because the interrupted inflow caused uncertainty to the matching of the observations with the theoretical Theis diagrams, the results are assessed to be suggestive.

A total of 26 monitoring sections were interpreted to have a direct hydraulic connection to the ONKALO tunnel intersection. The highest heads belong to monitoring sections in drillholes OL-KR1, -KR5, -KR20, and -KR39, i.e. the northwest area, and in open drillhole OL-KR40. The next group of the head diagrams shows the head of monitoring sections in drillholes with the longest distances to the tunnel intersection; OL-KR9, -KR27, -KR29 and -KR44 within the central area. The rest of the diagrams have a similar head level and responses to inflows into the tunnel. These drillholes are located at a distance of less than 400 m from the HZ20A tunnel intersection. To illustrate the head variation, one head diagram of each drillhole group is shown in Figure 5-22. In addition, the head diagrams of new HZ20 sections OL-KR16 L1 and -KR27 L1 are presented.

New HZ20 section OL-KR16 L1 is located close to the interpreted boundary of the central and northwest areas. Based on fitting geometry, OL-KR16 L1 would be part of the northwest spatial group, but the head in the monitoring section seems to follow the head level within the central part of the HZ20 system. The drawdown interpreted in the Olkiluoto monitoring programme in 2009 was 7.7 m in monitoring section OL-KR16 L1 and 1.7 – 2.2 m in nearby drillholes OL-KR1 (northwest area) and 9.2 – 9.7 m in -KR10 (central area) (Vaittinen et al. 2010a). No other direct hydraulic connections have been observed in drillholes OL-KR15, -KR17, and -KR18, located at a distance of no more than 50 m from -KR16 L1 indicating a local kind of connection (cf. more detailed in Chapter 5.4.2).

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3116 3121 3140 3170 3213 3263 3303 3317 3376HZ20A HZ20B

ONK-PH8

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PL3116

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T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

Figure 5-22. Interpreted direct hydraulic connections with current versions of zones HZ20A (red) and HZ20B (blue) (upper). The transmissivity of each connected packed-off section is visualised in both the section and the connecting tube by colour. Examples of head diagrams characterising the interpreted direct hydraulic connections (lower).

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KR29 L6

KR8 L1

KR9 L3

KR44 L1

KR1 L6

KR1 L7

KR39 L5

KR39 L4

KR20 L5

KR5 L8

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HZ20E

HZ20Central area

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HZ20Central area

Northwest area

Figure 5-23. Interpreted drawdown in monitoring sections as a function of distance, and the location of the central area and the northwest area (HZ20E) of the HZ20 system according to Vaittinen et al. (2010b).

Connections through smaller-scale hydrogeological zones Compared with the direct hydraulic connections applied to model zones HZ20A and HZ20B, the monitoring sections of this group typically have somewhat lower transmissivities and the drawdowns seem to be weaker. However, the responses have

98

the same timing as the sections included in the zones. The number of interpreted connections along smaller-scale features was 15 (Appendix 1). Two kinds of connections occur: single-hole connections and local features with several drillhole intersections. Example visualisations of both kinds of head diagrams are shown in Figure 5-24. Single-hole connections are determined in drillholes (monitoring section) OL-KR9 (L4), -KR10 (L4), -KR20 (L6), -KR25 L1, -KR29 L5, and -KR39 (L6,L7, L8).

The rest of the monitoring sections in this group have been modelled as local hydrogeological features with intersections in several drillholes. Sections OL-KR1 L8 and -KR2 L7 have been modelled as part of hydrogeological zone HZ002. Zone HZ002 was introduced in 2006 (Ahokas et al. 2007) but has been classified as a local-scale zone since 2008. Monitoring sections OL-KR15 L3, -KR16 L2, -KR17 L1, -KR20 L7, and possibly -KR2 L8 have been interpreted as part of zone Local_1 introduced in 2008 (Vaittinen et al. 2009). Both of these local-scale zones are located within the northwest area and have a hydraulic connection to the HZ20 system. More information on local features is given in Chapter 6.

Connections along single fractures Compared with other hydraulic connections, the head decreases slowly in monitoring sections interpreted to have a connection to the HZ20 system through single fractures with low transmissivity, cf. Figure 5-25. These monitoring sections have low transmissivity and the interpreted pressure responses are smooth and the recovery of the head slow. The head decreases over a period longer than the duration of inflow indicating a poor hydraulic connection. A total of 17 poor hydraulic connections (cf. Appendix 1) were interpreted of which three example head diagrams were selected for visualisation (Figure 5-25).

Single-hole hydraulic connections occur in drillholes (monitoring section) OL-KR1 (L5), -KR4 (L2), -KR5 (L6, L7), -KR9 (L1, L2), -KR10 (L3), -KR15 (L1, L2), -KR20 (L3, L4), -KR27 (L2), and -KR28 (L1). In addition, drillholes OL-KR16 (L3), -KR17 (L2, L3), and -KR18 (L1) are interpreted to probably be primarily connected to a local zone following the interpretation of aforementioned zone Local_1.

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337633173303326332133170314031213116HZ20BHZ20A

PL3312

PL3307PL3288

INJ3273TR3273

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337633173303326332133170314031213116HZ20BHZ20A

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T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

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T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

Figure 5-24. Interpreted connections through smaller-scale hydrogeological zones withcurrent versions of zones HZ20A (red) and HZ20B (blue) (upper). The transmissivity of each connected packed-off section is visualised in both the section and the connecting tube by colour. Examples of head diagrams characterising interpreted connections (lower).

100

337633173303326332133170314031213116HZ20BHZ20A

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KR01 L5 311.2-336.8 KR09 L2 519.8-525.4 KR27 L2 421-430 ONKALO chainage Inflow

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

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337633173303326332133170314031213116HZ20BHZ20A

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PL3307PL3288

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KR01 L5 311.2-336.8 KR09 L2 519.8-525.4 KR27 L2 421-430 ONKALO chainage Inflow

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

Figure 5-25. Interpreted connections along fractures with current versions of zones HZ20A (red) and HZ20B (blue) (upper). The transmissivity of each connected packed-off section is visualised in both the section and the connecting tube by colour. Examples of head diagrams characterising interpreted connections (lower).

101

Geophysics

Several geophysical investigation methods support the existence of the HZ20 system: galvanic cross-hole Mise-à-la-masse measurements (Paananen et al. 2007, Tarvainen 2008), electromagnetic Gefinex measurements on the ground surface (Paananen et al. 2007), 3D surface seismics (Juhlin & Cosma 2007), Vertical Seismic Profiling (VSP) and Walkaway VSP (WVSP) carried out in drillholes OL-KR4, -KR8, -KR10, and -KR14 (Enescu et al. 2004), and seismic 2D reflection processing (Öhman et al. 2006). In addition, anomalous sections in P-wave velocity as well as short normal and long normal resistivity characterise the internal properties of the HZ20 system. A description of the utilisation of geophysical data is given in Mattila et al. (2008) and Aaltonen et al. (2010) related to corresponding geological brittle fault zones.

3D surface seismics carried out in the eastern area of the site and the seismic HIRE survey measured since the 2008 version provide supporting data between the drillholes and to some extent outside the area covered by deep drillholes. The modelled zones and examples of the seismic results are visualised in Figure 5-26 (cf. also Chapter 3.3 and Figure 3-16). Also, the interpreted electrical Mise-à-la-masse conduits coincide with high fracture transmissivities modelled to the HZ20 system, cf. Figure 5-27. It is noteworthy that electrical conduits follow both ductile feature FDZ and the hydraulic connection within the northwest area towards the ground surface.

Although geophysical measurements support the interpretation of the HZ20 system, the continuity of these geophysical features is somewhat larger than that of the hydrogeological zones at the site, probably due to heterogeneity within brittle deformation zones as described in Chapter 4.1. Geophysical data cannot therefore be straightforwardly applied to determine the extent of the hydrogeological zones. This can be clearly seen, when HZ20A and corresponding brittle fault zone OL-BFZ020A, the continuity of which is based on geophysics, are compared, the latter being considerable larger than HZ (see discussion in Chapter 3.1.1).

102

Figure 5-26. Zones HZ20A (red) and HZ20B (blue) and a detail of the seismic HIRE profile, view towards northeast. View from above shows the location of the profile. The zones are cut in front of the profile. An explanation for the seismic data is given in Chapter ��.

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FDZFDZ

Figure 5-27. Zones HZ20A (red) and HZ20B (blue), FDZ, and coinciding electrical Mise-à-la-masse conduits (blue lines), view towards southeast.

Geological setting

Considering the main tectonic units, the HZ20 system is located within CTU between SDZ and LSZ. As discussed in the context of pressure responses, an indication of a change in hydraulic connectivity towards northwest was interpreted (Vaittinen et al. 2009b). An explanation to this change is probably related to the occurrence of HZ20A within SW-NE striking ductile deformation zone FDZ between sub-units CTU1 and CTU2. Hydraulic connectivity along FDZ is assessed to be better than connectivity between FDZ and CTU1 due to the more uniform orientation of foliation.

The locations of the drillhole sections interpreted to form direct hydraulic connections within the HZ20 system are visualised in Figure 5-28 with the ductile deformation model. The ductile deformation model describes the ground surface areas, where one deformation phase is dominant. No accurate boundaries can be determined. The dip of the deformation zones is based on the dip of the foliation typical of that deformation phase. Taking into account the statistical character of the deformation zones, the locations of the drillhole sections indicate spatial connection between the HZ20 system and FDZ within the central area towards southeast. The northwest area, on the other hand, is outside of FDZ.

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SDZ

FDZ

F4-1

SDZ

FDZ

F4-1

Figure 5-28. Location of the drillhole sections interpreted to form direct hydraulic connections within the HZ20 system and coinciding electrical Mise-à-la-masse conduits (blue lines). Red circles refer to zone HZ20A and blue circles to zone HZ20B.

The spatial connection of the HZ20 system and FDZ can be explained by the reactivation of the ductile and semi-ductile deformation structures (foliation, shear zones) of FDZ within later brittle deformation. Brittle fault zone OL-BFZ020 corresponding to HZ20 is located within FDZ, and is interpreted to be a ductile thrust fault in origin. During subsequent brittle deformation, it has been reactivated first as a normal fault and then in a strike-slip regime (Aaltonen et al. 2010), resulting in a polyphased brittle fault zone with potential conduits for groundwater flow.

5.4.3 HZ20 system boundaries

Reasoning for the determined boundaries of the HZ20 system is given in the following Sections and the locations of the boundaries are shown in Figure 5-29.

105

Figure 5-29. Locations of the boundaries of the HZ20 zones and the discussed drillholes, view from above.

Towards north Following the simplified description of the HZ20 system applied in 2008, only the upper surface of the interpreted direct connections is modelled in the northwest area. The thickness of the HZ20 system is rather thin within the northwest area and the HZ20A and HZ20B zones are therefore combined for numerical modelling purposes. The northernmost direct hydraulic connection is interpreted to be in drillhole OL-KR5 level L8 located at a depth of ca. 40 m below ground surface.

A hydraulic connection has been observed between open drillhole OL-KR33 and monitoring sections OL-KR5 L5-L8 during the drilling and pumpings of drillhole OL-KR33, but it has been interpreted as a local connection to the HZ20 system (cf. Chapter 6). The reason is that based on the timing of drilling and the observed responses, the most probable connection is through a hydraulically conductive fracture at a depth of 151.3-153.3 m (Vaittinen et al. 2008), which is ca. 100 m deeper than zone HZ20A in nearby drillhole OL-KR5, i.e. the geometry would not follow the typical orientation of foliation.

106

The edge of the system towards east seems to be quite sharp within the northwest area. E.g., there is no indication of a hydraulic connection to the HZ20 system visible in drillhole OL-KR21 located close to drillhole OL-KR5. The transmissivity of both monitoring sections is of the same order of magnitude, 4.2·10-7 m2/s in KR5 L8 and 8.4·10-7 m2/s in open drillhole OL-KR21. In addition, only one monitoring section OL-KR16 L1 in drillholes OL-KR15 � -KR18 has a direct hydraulic connection to the HZ20 system, although the drillholes are less than 50 m apart.

Towards east Drillhole OL-KR27 was packed-off at the end of 2007, and based on flow and pressure responses, zone HZ20A was extended to the drillhole (cf. Figure 5-21).

Zone HZ20B was extended towards east following the seismic HIRE and 3D surface seismic results (cf. Figure 5-26). The extended part does not intersect any drillholes.

Towards south The boundary of the HZ20 system towards south cannot be determined on the basis of hydraulic data, because hydraulic responses have been observed in the southernmost drillhole OL-KR8. Only zone HZ20B was modelled to intersect drillhole OL-KR8 in 2008.

Based on a reinterpretation of the head diagrams in drillhole OL-KR8 during the packing-off period in 2003, zone HZ20A is extended to the drillhole. The reinterpretation result is based on similar hydraulic properties in nearby drillhole OL-KR27 and on the experience of the effect of packing-off drillholes on drawdowns. The monitoring section connected to the HZ20A zone has not been packed-off since 2003.

The concept of probably varying hydraulic properties within each tectonic unit was taken into account and the extent of the HZ20 system towards south was restricted in 2008. Compared with the previous model, the orientation of LSZ in the ductile deformation model and corresponding brittle fault zone OL-BFZ146 in the brittle deformation model has been changed from steeply-dipping to gently-dipping. Based on seismic HIRE data (cf. Kukkonen et al. 2010), the continuity of the HZ20B zone has been extended towards southeast below LSZ. No new drillhole intersections were included in the zone.

Towards west The drillhole intersection in drillhole OL-KR29 was changed from monitoring section L5 to section L6 based on the hydrogeological analysis of hydraulic effects during the excavation of the ONKALO access tunnel (Vaittinen et al. 2010). Both the transmissivity of the sections and the analysed pressure responses support section L6 being a direct connection, instead of L5.

No hydraulic responses related to the HZ20 system have been observed in drillhole OL-KR3. The boundary is therefore set between drillholes OL-KR39 and -KR3.

Sub-vertically In many of the drillholes the HZ20 system is compact and sharply distinguishable from averagely fractured rock, based on high fracture transmissivity values. However, the

107

long-term drawdown caused by the leakage of the HZ20 zones into ONKALO enabled observation of weak hydraulic connections to the HZ20 system. The concept of the system has therefore changed slightly. Although the extent of the system is still assessed to be restricted compared with the earlier assumption, minor connections enlarge the extent of hydraulic effects on the surrounding rock (cf. Chapter 5.4.7).

The mapped observations of the HZ20 system on the bedrock surface have not been confirmed. The direct hydraulic connection interpreted to be the closest to the ground surface is the topmost monitoring level in drillhole OL-KR5 at a depth of ca. 40 m below the ground surface. Monitored shallow drillhole OL-PR2 with a depth of 13 m is located close to drillhole OL-KR5. A drawdown following the HZ20 system is interpreted to occur in OL-PR2 (Vaittinen et al. 2010a).

The hydraulic connection reaches the topmost packed-off sections in drillholes OL-KR20 and -KR39 and also in open drillhole -KR20B. However, direct connections are interpreted at a depth range of 85 – 135 m below the ground surface, but possibly due to the densely fractured bedrock or sub-vertical features, pressure responses are visible up to the topmost monitoring levels.

5.4.4 Zone HZ20A

Zone HZ20A describes the upper surface of the interpreted direct hydraulic connections included in the HZ20 system. There are hydraulic responses above the modelled HZ20A in drillholes OL-KR9, -KR20, -KR23, -KR27, and -KR39, but they are assessed to be local connections. The geometry of these local features is not known.

Compared with the previous version, zone HZ20A is extended to intersect drillholes OL-KR8, -KR16, and -KR27 as described in Chapter 5.4.2. Following the previous 2008 model, the zone reaches the sea and intersects zones HZ001 and HZ099 located within NTU, although the current understanding of the site suggests that hydraulic connections occur within each tectonic unit (cf. Chapter 4.2). However, no new investigation data were available on this area.

Within the northwest area in drillholes OL-KR1, -KR20, and -KR39, the interpreted upper and lower surfaces of the HZ20 system are located close to each other in proportion to the accuracy of the numerical EPM model. Therefore the hydraulic properties are modelled with only one zone (HZ20A) for numerical modelling purposes. The reason is to avoid differences between the hydrogeological structure model and numerical groundwater flow models. Transmissivity attached to zone HZ20A is the sum of both the zones in these drillholes.

The average orientation of the zone is 109/15° in terms of dip direction and dip. Zone HZ20A and corresponding brittle deformation zone OL-BFZ020A are visualised in Figure 5-30. The drillhole depth intervals for the zone and for the transmissivity depth range, the defining method for the transmissivity depth range (cf. Chapter 2.4.1), and the drillhole-specific transmissivities of zone HZ20A are shown in Table 5-5. The transmissivities are also visualised in Figure 5-31, which shows values in both 2008 and 2010. The most notable change in the transmissivity values occurs in drillhole OL-KR29 due to the changed intersection depth.

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T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

Figure 5-30. Zones HZ20A (red) and OL-BFZ020A and fracture transmissivities, view towards northeast.

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Table 5-5. Drillhole depth intervals for the zone and for transmissivity (T) depth ranges, the defining method applied for T depth ranges (cf. Chapter 2.4.1), and drillhole specific transmissivities of zone HZ20A.

HZ20A Zone intersection, m T depth range, m T, m2/s log T Note OL-KR01 105.9 114.3 99.0 169.5 1 2.5E-05 -4.6 1), 2) OL-KR04 306.2 314.9 298.0 325.0 1 2.0E-05 -4.7 2) OL-KR05 42.0 44.0 27.0 59.0 2 3.4E-07 -6.5 OL-KR07 224.2 249.9 191.0 257.5 1 4.1E-05 -4.4 OL-KR08 451.7 454.5 448.0 458.0 1 1.9E-07 -6.7 OL-KR09 443.2 446.0 437.0 450.0 1 4.8E-07 -6.3 4) OL-KR10 260.0 262.0 238.0 275.5 1 1.0E-05 -5.0 3) OL-KR16 151.6 153.6 136.6 168.6 2 2.3E-07 -6.6 OL-KR20 109.4 111.4 94.4 157.0 2 9.5E-06 -5.0 1) OL-KR22 390.4 392.4 382.5 397.5 1 3.7E-05 -4.4 5) OL-KR23 425.9 430.0 420.0 460.3 1 1.2E-06 -5.9 OL-KR24 303.6 306.0 294.0 347.8 1 2.4E-05 -4.6 OL-KR25 342.6 352.5 340.0 355.0 1 4.3E-05 -4.4 OL-KR27 503.8 505.8 488.8 520.8 2 3.7E-07 -6.4 OL-KR28 388.3 390.8 379.0 395.0 1 5.2E-05 -4.3 OL-KR29 167.0 175.2 152.0 254.0 2 1.4E-05 -4.8 OL-KR38 306.6 309.2 305.0 357.3 1 4.5E-05 -4.3 OL-KR39 108.0 111.2 53.9 166.7 1,2 3.1E-05 -4.5 1) OL-KR48 297.4 299.4 282.4 330.0 2 4.4E-06 -5.4 ONK-PH08 50.9 52.9 35.9 67.9 2 7.7E-07 -6.1 1) T depth range contains both HZ20A and HZ20B 2) Results of long-term pumping test also used in the determination of transmissivity 3) Uncertain due to cemented section 4) 2 m PFL assumed to be more representative than 0.5 m value 5) Highest PFL values are assumed to be disturbed by ONKALO and other activities - values from year 2002 better showing T in the order of 1...4E-5 m2/s

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HZ20A

KR39KR20

KR07

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KR01

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KR38

KR29

KR28

KR25

KR24

KR23

KR22

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KR09

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KR39

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KR29

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KR25

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KR09KR08

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500

-10 -9 -8 -7 -6 -5 -4 -3log T (m2/s)

Dep

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)

T 2008T 2010

Figure 5-31. Measured transmissivities of zone HZ20A. T 2008 refers to the transmissivities of the 2008 model and T 2010 to the current version. Drillhole intersection in OL-KR29 has been changed.

5.4.5 Zone HZ20B

Zone HZ20B describes the lower surface of the interpreted direct hydraulic connections included in the HZ20 system. Drillhole sections with observed responses related to the HZ20 system below the modelled HZ20B occur in drillholes OL-KR5, -KR9, and -KR10. The transmissivities of these sections are quite low, below 2·10-8 m2/s. Hydraulic responses below the modelled HZ20B are assessed to be local connections, cf. Chapter �. The geometry of these local features is not known.

Within the northwest area in drillholes OL-KR1, -KR20, and -KR39, only the upper surface (HZ20A) is modelled for numerical purposes (cf. Chapter 5.4.4). The transmissivity of the HZ20B intersections is included in the transmissivity of zone HZ20A.

Compared with the previous model, zone HZ20B is extended towards east – southeast following the seismic HIRE and 3D seismic anomalies (cf. Kukkonen et al. 2010). No new drillhole intersections have been modelled to the zone.

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T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

The average orientation of the zone is 138/22° in terms of dip direction and dip. HZ20B and corresponding OL-BFZ020B zones are visualised in Figure 5-32. The drillhole depth intervals for the zone and for transmissivity depth ranges, the defining method for the transmissivity depth range (cf. Chapter 2.4.1), and the drillhole specific transmissivities of zone HZ20B are shown in Table 5-6. Transmissivity values in both 2008 and 2010 are visualised in Figure 5-33.

Figure 5-32. Zones HZ20B (blue) and OL-BFZ020B and fracture transmissivities, view towards northeast.

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Table 5-6. Drillhole depth intervals for the zone and for he transmissivity (T) depth ranges, the defining method applied for T depth ranges (cf. Chapter 2.4.1), and drillhole specific transmissivities of zone HZ20B.

HZ20B Zone intersection, m T depth range, m T, m2/s log T Note OL-KR01* 151.8 153.8 99.0 169.5 1 2) OL-KR04 365.3 367.3 353.0 376.0 1 1.0E-05 -5.0 1) OL-KR07 279.6 287.1 260.0 310.0 1 1.6E-05 -4.8 OL-KR08 547.6 561.0 533.0 570.0 1 1.6E-05 -4.8 OL-KR09 468.6 480.0 468.0 503.5 1 2.1E-06 -5.7 OL-KR10 326.6 328.6 318.0 333.0 1 1.0E-06 -6.0 1) OL-KR20* 138.0 142.0 125.7 157.0 2 2) OL-KR22 423.0 426.4 401.5 452.5 1 5.4E-06 -5.3 OL-KR24 396.0 398.3 377.0 405.5 1 4.0E-06 -5.4 OL-KR25 405.5 408.8 363.0 423.8 1,2 1.7E-05 -4.8 OL-KR28 442.9 447.2 440.0 539.6 1 6.0E-06 -5.2 OL-KR29 320.6 340.9 302.0 357.0 1 5.9E-06 -5.2 OL-KR38 378.7 391.6 372.0 393.0 1 1.3E-05 -4.9 OL-KR39* 147.2 151.7 110.3 166.7 2 2) OL-KR40 605.2 612.9 598.0 616.5 2 4.8E-07 -6.3 OL-KR44 652.1 654.1 637.1 693.4 2 3.1E-06 -5.5 OL-KR48 377.7 383.9 330.0 398.9 2 8.4E-07 -6.1 ONK-PH09 38.4 40.4 23.4 55.4 2 4.9E-07 -6.3 *Not used for zone modelling 1) Results of long-term pumping test also used in the determination of transmissivity 2) Fracture transmissivities included in HZ20A

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HZ20B

KR08

KR04

KR07

KR09

KR10

KR22KR24

KR25KR28

KR29

KR38

KR40

KR44

KR01KR20

KR39

PH09

KR48

KR44

KR40

KR38

KR29

KR28

KR25KR24

KR22

KR10

KR09

KR08

KR07

KR04

0

100

200

300

400

500

600

700

-10 -9 -8 -7 -6 -5 -4 -3log T (m2/s)

Dep

th (m

)

T 2008T 2010

Figure 5-33. Measured transmissivities of zone HZ20B. T 2008 refers to the transmissivities of the 2008 model and T 2010 to the current version.


Corresponding brittle fault zones OL-BFZ020A and -BFZ020B are gently dipping faults with an approximate dip direction and dip of 155/20° and 140/20°, respectively (Aaltonen et al. 2010). OL-BFZ020A is located sub-parallel to and only some tens of meters above fault zone OL-BFZ020B, and these two seem to form the upper and lower parts, respectively, of a double-sided fault system. The core zones of the faults in the drillholes are typically ca. 1 m thick. The fault core consists of densely fractured (RiIII) and clay-filled sections (RiIV) in most of the intersecting drillholes. Hydraulic conductivity is commonly also elevated. In some drillholes, the fault core is characterised by pervasive or fracture-controlled illitisation, kaolinitisation and sulphidisation or weathering. Geophysically, the zones are observed in several drillholes as a P-wave minimum and an electric conductor. Their geometry is strongly based on Mise-à-la-masse results, seismic reflectors revealed by VSP, 3D and 2D reflection surveys and Sampo Gefinex conductors.

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Fault zone OL-BFZ020A is intersected by 33 drillholes and the ONKALO access tunnel at chainage 3 159 m. In 17 drillholes, zone OL-BFZ020A is fixed to a brittle fault or joint intersection, and in 12 drillholes to a fractured RiIII-IV section. Clear geological indications are lacking in six drillholes (OL-KR2, -KR16, -KR20, -KR24, -KR41 and -KR46). However, the zone is modelled to intersect these locations according to the general geometry or Mise-a-la-Masse results. The geometry and extent of OL-BFZ020A to SE is also supported by the HIRE seismic reflection survey (Kukkonen et al. 2010).

Fault OL-BFZ020B is intersected by 16 drillholes. In 11 drillholes, the fault is fixed to a brittle fault or a brittle joint intersection and in 5 holes to RiIII-IV sections based on the general geometry and/or Mise-a-la-Masse results. In the ONKALO access tunnel, it has been fixed to a brittle fault intersection at chainage 3 285 m.

Alteration is a characteristic feature of OL-BFZ020A and -BFZ020B. It appears either as pervasive kaolinisation or illitisation around the core or as abundant kaolinisation, sulphidisation and illitisation in fractures. Alteration is not seen within the ONKALO area, but is abundant east and north of it.

The average widths of the core zones in OL-BFZ020A and -BFZ020B are 0.9 m and 2 m, respectively. The average widths (the intersection length at the drillhole) of the upper and the lower influence zone of OL-BFZ020A are 19.9 m and 10.8 m, respectively. In OL-BFZ020B the corresponding widths are 12.3 m and 16.4 m. The main defining characteristic for the influence zones in many intersections is continuous hydrological conductivity both in the core section and in the influence zone. Geophysical anomalies, the acoustic long normal and short normal minimum, are very important tools in defining the influence zones. In most cases they seem to describe the influence zone together with hydraulic conductivity although fracturing has decreased and no other significant features are identifiable (Mattila et al. 2008, Aaltonen et al. 2010).

Fault zone OL-BFZ020A has been modelled to reach the surface and fixed to a topographic lineament crossing Olkiluoto Island in a northeast – southwest direction. Towards the northeast, southwest, and southeast, the fault zone has been extrapolated to the bounding lineaments offshore.

The HZ20 zones and the corresponding brittle fault zones are visualised in Figure 5-16. The locations of both the cores and the influence zones are shown in Appendix 1.

5.4.7 Hydraulic connections to sparsely fractured rock

The extent of the sub-horizontal HZ20 system seems to be quite restricted in both horizontal and vertical directions, although the observations of weak hydraulic connections to sparsely fractured rock have changed the concept of the system since 2008. At that time only few hydraulic connections outside the modelled HZ20 zones were interpreted.

To characterise the hydraulic connections from the HZ20 zones to sparsely fractured rock, a 3D visualisation of the drillhole zone intersections of the HZ20 zones and the drillhole sections of the other interpreted hydraulic connections is provided (cf. Figure 5-34). Only drillholes with an interpreted connection are shown. Hydraulic connections

115

are visualised in Appendix 1, too. In most of the cases, detailed interpretation of the connected fractures cannot be carried out, but the whole monitoring section is highlighted.

Within the northwest CTU1 area, where the system is above -150 m.a.s.l., the HZ20 system seems to have a hydraulic connection to a wide depth range. Possibly due to the increased depth or the hydraulic properties of FDZ and CTU2 the system is more restricted within CTU2. On the other hand, a few of the responded monitoring sections are located at a distance of more than 100 m from the modelled zones. Hydraulic connections below the system in drillholes OL-KR1, -KR4, -KR7, -KR10, and -KR28 (Figure 5-34) are interpreted to belong to a new zone HZ056 described in Chapter 5.11.2.

The observation of weak hydraulic connections is strongly dependent on the location of monitoring sections for pressure responses and on possibilities to measure flow responses. The the observation of connections is therefore biased (cf. also Chapter 6).

5.4.8 Uncertainties

The HZ20 system is connected to the ground surface and the sea along zone HZ20A. The location of the ground intersection is highly uncertain, because no direct mapping observations have been made.

The packed-off head data currently available do not enable an assessment of sub-vertical hydraulic connections within the HZ20 system, i.e. between zones HZ20A and HZ20B. The uncertainty is caused by hydraulic short-circuit within drillhole OL-KR7, where both zones are located in the same packed-off section. However, in the excavation through the HZ20 zones no grouting was required between the zones over a tunnel length of approximately 80-100 m, which proves the existence of at least locally distinct zones.

116

Figure 5-34. 3D visualisation of the modelled HZ20A (red) and HZ20B (blue) zone intersections, and monitoring sections (green) with interpreted weaker hydraulic connections, views from above (upper) and towards northeast (lower).

117

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

HZ21

HZ001

HZ099OL-BFZ099

OL-BFZ021

HZ21B


The hydrogeological zones described in this Chapter are HZ21, HZ21B, HZ099, and HZ001 (cf. Figure 5-35). According to corresponding brittle deformation zones OL-BFZ021 and -BFZ099 modelled in GSM version 2.0 (Aaltonen et al. 2010), the hydrogeological zones form two splays in the northern part of the island but conjoin in the middle of the island. At this point zone HZ21 corresponds to OL-BFZ021, while the continuation of the zone towards the SE corresponds to the SE part of OL-BFZ099. Zone HZ001 is reported in this Chapter because the location of the zone in the vicinity of and following the same orientation as deformation zone OL-BFZ099 indicates that the zones may be located in the same geological context. All of these zones are located within NTU.

Figure 5-35. Locations of the HZ21 (brown), HZ21B (blue), HZ099 (red), and HZ001 (orange) zones and corresponding brittle deformation zones OL-BFZ099 (upper) and OL-BFZ021 (lower), view towards east-northeast.

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5.5.1 Background

Hydraulic connections in the northern tectonic unit do not seem to form as extensive zones as the hydrogeological zones located in the central unit. There are many uncertainties related to the interpretation of pressure responses, which form the basis for the assessment of the continuity of the zones. The rather long distances between the drillholes towards east from drillholes OL-KR6 and -KR12, in particular, increase uncertainty within the NTU. However, the hydraulic properties of drillhole OL-KR6 are assessed to be quite similar to e.g. drillhole OL-KR8 in terms of total transmissivity and distinct high fracture transmissivities. During the previous modelling campaign, it was therefore assessed that the long-term pumping test carried out in drillhole OL-KR6 starting in March, 2001 (Hirvonen et al. 2007) should have caused responses in nearby drillholes, e.g. OL-KR2, -KR13, and -KR19, if there were hydraulic connections. Only drillholes up to OL-KR12 were drilled at the time the pumping test started, but the changes in pumping rate and the temporary breaks of a few days in pumping could cause responses. In nearby multilevel piezometer OL-EP4, the average head level decreased by about 1.5 m on observation levels L1 – L3 in the depth range of 30 – 103 m.b.g.s., when pumping started in drillhole OL-KR6. The uppermost level L4 (3 – 14 m.b.g.s.) was not affected by the pumping.

The decision to decrease the extent of hydrogeological zones HZ001 and HZ099 towards east in 2008 was based on lacking pressure response observations and the preliminary concept of differences in geological and hydrogeological properties of the tectonic units, although it is known that pressure responses may be obscured by the effects of open drillholes or the nearby ground surface, and that packed-off sections do not cover all transmissive fractures. The monitoring of head improved when drillhole OL-KR13 was packed-off in September 2007 and drillhole OL-KR19 in September 2009. So far, short-term pressure changes in drillhole OL-KR6 have caused visible responses in drillhole OL-KR19 (�� ).

Zone HZ21

The first version of zone HZ21 was introduced in the bedrock model in 1993 as local gently dipping zone R21 (Saksa et al. 1993). Only one drillhole intersection, in drillhole OL-KR5, was included in zone R21 at that time. Zone R21 was changed into a site-scale zone and extended to drillholes OL-KR1, -KR2, and -KR4 in 1997 (Saksa et al. 1997). Since 1997, zone HZ21 has been extended as new intersecting drillholes have been drilled, but due to the planar geometry of the zone orientation has remained almost unchanged since the first local version.

The interpretation of zone HZ21 has been strongly based on the geological properties of the zone and the results of geophysical measurements. Only fragmental hydraulic connections have been observed between the drillholes. In addition, the transmissivity of the HZ21 intersections varies by several orders of magnitude. Zone HZ21 has been kept in the hydrogeological model assembly due to its intensive fracturing and its possible role as a major route for deep saline groundwater as well as for radionuclides from repository level to the biosphere (Ahokas et al. 2007).

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Zone HZ21B

Zone HZ21B was introduced by Ahokas et al. (2007). It was modelled to connect the observed high fracture transmissivities in drillholes OL-KR4, -KR6, and -KR12. The geometry of the zone intersects zone HZ21. Due to the lack of continuation data on the zone and because three out of eight drillhole intersections are common with zone HZ21, it was classified as an alternative zone in 2008.

Zone HZ099

The modelling of zone HZ099 is based on geological brittle fault zone OL-BFZ099 (Aaltonen et al. 2010). The HZ was included in the model assembly in 2006 (Ahokas et al. 2007) according to fault zone OL-BFZ099 in GSM version 0 (Paulamäki et al. 2006) without changes in geometry but two transmissivity values were assigned to the zone as a function of depth. Zone OL-BFZ099 was significantly widened in version GSM 1.0 (Mattila et al. 2008), and modified zone HZ099 was therefore introduced in 2008 (Vaittinen et al. 2009). The central part of BFZ with moderate fracture transmissivities was modelled as a hydrogeological zone.

Zone HZ001

Zone HZ001 connects drillhole sections with an anomalous low head located in the northern part of the Island. A head analysis has been carried out to present as representative fresh water heads as possible, i.e. baseline heads, for the selected drillholes used in the Monitoring Programme to identify and determine any disturbances in groundwater conditions caused by the ONKALO (Ahokas et al. 2008). Anomalous low heads were detected, and zone HZ001 was on the basis of these observations introduced in 2006 (Ahokas et al. 2007).

The extent of hydrogeological zone HZ001 was decreased towards east in 2008. The decision was based on the preliminary concept of differences in the geological and hydrogeological properties of the tectonic units and the lack of pressure responses.


Boundaries for the HZ21 zones are visualised in Figure 5-36.

Zone HZ21

Due to dense fracturing and a notable thickness, zone HZ21 can be observed in geophysical measurements and the continuity of the zone has been strongly based on VSP measurements (cf. Cosma et al. 2003, Enescu et al. 2003, Vaittinen et al. 2003). In addition, a hydraulic connection has been observed along modelled zone HZ21 between drillholes OL-KR1 and -KR2 and between drillholes OL-KR5 and -KR19. A description of the modelling data applied until 2003 is given in Vaittinen et al. (2003). Since 2003, the results of Walkaway VSP (WVSP) carried out in drillholes OL-KR4, -KR8, -KR10, and -KR14 (Enescu et al. 2004), the cross-hole Mise-à-la-masse measurements (Paananen et al. 2007, Tarvainen 2008), the 3D surface seismics (Juhlin & Cosma 2007) and the electromagnetic Gefinex measurements on the ground surface (Paananen et al. 2007) have supported modelled zone HZ21. The results of the geophysical measurements are summarised in Mattila et al. (2008) and Aaltonen et al. (2010).

120

Figure 5-36. Locations of the boundaries of the HZ21 zones, brown refers to zone HZ21, blue to HZ21B, red to HZ099 and orange to HZ001, view from above. Boundaries with bounding lineaments (upper) and with drillhole information (lower).

121

The interpretation of the geophysics and the geological properties of the drillhole intersection supported a large extension of the zone in the area covered by deep drillholes and probably towards west. Since 2008, seismic HIRE survey and 3D seismic investigations within the eastern area provide confirming information on the properties of zone HZ21 (Cosma et al. 2008, Kukkonen et al. 2010). Continuity towards southeast is supported by HIRE survey and towards east by 3D seismic results, �cf. �� . Because there are no results suggesting limitation of the zone, the zone is extended to the eastern and western boundary lineaments, i.e. the current version of zone HZ21 covers Olkiluoto Island.

Hydraulic responses between drillholes OL-KR1 and -KR2 and drillholes OL-KR5 and -KR19 related to the HZ21 zone are described in Vaittinen et al. (2009). No indications of new hydraulic connections have been observed since the previous 2008 model version. A new drillhole intersection in drillhole OL-KR47 is determined following corresponding BFZ and taking nearby transmissive fractures into account.

Figure 5-37. Modelled zone HZ21 (brown) and a detail of the seismic HIRE profile and one slice of 3D seismic surveys in the eastern part of the Island, view towards southwest. View from above to illustrate the location of the data. The zones are cut in front of the profile. An explanation of the seismic data is given in Chapter ��.

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Zone HZ21B

The HZ21B zone was modelled to explain the two high and the one moderate fracture transmissivity measured in drillholes OL-KR4, -KR6, and -KR12. One hydraulic connection is interpreted along zone HZ21B. A pressure response was interpreted in monitoring section OL-KR5 L2 during the drilling of drillhole OL-KR19 (Ahokas et al. 2007). The zone was classified as an alternative zone in 2008. Based on new data between drillholes obtained by seismic HIRE and 3D seismic surveys, zone HZ21B is included in the basic model. Seismic data support the concept of possibly intersecting or sub-parallel features close to zone HZ21 in the northwest area, cf. Figure 5-38. The geometry of zone HZ21B has not been changed since 2008.

Figure 5-38. Modelled zones HZ21 (brown) and HZ21B (blue) and a detail of the seismic HIRE profile and one slice of 3D seismic results in the western part of the site, view towards northeast. View from above to illustrate location of the data. The zones are cut in front of the profile. Explanation for the seismic data is given in Chapter ��.

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Zone HZ099

The hydrogeological properties of the OL-BFZ099 zone seem to follow the same kind of behaviour as e.g. the HZ20 zones. I.e. the continuity of the brittle deformation zone based on geophysical Mise-à-la-masse measurements is significantly larger than the area with moderate fracture transmissivities. Therefore, a modified version of zone HZ099 covering a considerably smaller area than the corresponding BFZ was modelled in 2008.

Because several of the drillholes within the NTU are open, the interpretation of hydraulic connections based on pressure responses is uncertain. Only one hydraulic connection along zone HZ099 has been interpreted. When drillhole OL-KR13 was drilled, a pressure response occurred between drillhole OL-KR13 and packed-off drillhole -KR2 (Vaittinen et al. 2008b). In 2008, an assessment was carried out on whether pressure responses should be visible due to the long-term pumping test in drillhole OL-KR6. Because no responses were observed in the nearest drillholes OL-KR2, -KR13, and -KR19, drillhole OL-KR6 was excluded from zone HZ099 and the western boundary was set between drillholes OL-KR19 and -KR6. Uncertainties related to the decision were discussed in Vaittinen et al. (2009).

The monitoring of head improved when drillhole OL-KR13 was packed-off in September 2007 and drillhole OL-KR19 in September 2009. So far, short-term pressure changes in drillhole OL-KR6 have caused visible responses in drillhole OL-KR19 (�� ). �Due to pumping out of an open drillhole, pressure responses are shown in all packed-off sections above ca. -250 m.a.s.l. The extension of zone HZ099 to drillhole OL-KR6 therefore follows corresponding zone OL-BFZ099. Also, drillhole OL-KR12 was included in HZ099 based on the geophysical continuity interpreted for zone OL-BFZ099 and moderate fracture transmissivities.

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OL-KR19

-5

-4

-3

-2

-1

0

1

2

3

4

5

1.3.10 11.3.10 21.3.10 31.3.10 10.4.10 20.4.10 30.4.10 10.5.10 20.5.10 30.5.10

Date

Hea

d, m

.a.s

.l.

KR19 L1 454-468 KR19 L2 319-328 KR19 L3 249-263 KR19 L4 199-213 KR19 L5 144-153 KR19 L6 69-108KR19 L7 54-58 KR19 L8 40-53 Sea Level Reference fluctuation KR06 Open

Figure 5-39. Head diagrams of packed-off drillhole OL-KR19 and open drillhole--KR6. Pressure responses caused by temporary breaks in ongoing long-term pumping in OL-KR6 are visible in monitoring sections OL-KR19 L3 – L8 e.g. on 10.4.2010.

Zone HZ001

Anomalous low heads are detected in each of the northern drillholes: OL-KR5, -KR6, -KR11, -KR13, -KR19, -KR33, and -KR43 (Ahokas et al. 2008). Connections to the sea or the shore area can be either direct or along sub-horizontal fractures or zones. As the present modelling is compiled from the site-scale point of view, one zone HZ001 with probable hydraulic connections has been modelled. The other low head zones would have been based on one drillhole observation each and as local features were not included in the model.

The modelling of zone HZ001 is based on observations of transmissive fractures with anomalous low heads forming a relatively planar geometry. Drillholes OL-KR13 and -KR19 have been packed-off since the previous model, but due to open drillholes OL-KR6, -KR33 and -KR43, unambiguous pressure responses are so far not available. Zone HZ001 is extended to drillhole OL-KR6 with the same reasoning as zone HZ099, cf. the previous Section.

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5.5.3 Zone HZ21

Zone HZ21 is located below the planned depth of the repository. The zone is intensively fractured and thereby plays a possible role as a major route for deep saline groundwater as well as for radionuclides from repository level to the biosphere. Compared with the previous version, zone HZ21 is extended to the bounding lineaments both towards east and west, i.e. each edge of the zone is connected to the boundary of the model and the intersection with drillhole OL-KR47 is determined.

The average orientation of the zone is 162/20° in terms of dip direction and dip. The 3D visualisation of the zone and the transmissivities are shown in Figure 5-40. The drillhole depth intervals for the zone and for transmissivity depth ranges, the defining method for the transmissivity depth range (cf. Chapter 2.4.1), and the measured drillhole specific transmissivities of zone HZ21 are shown in Table 5-7. The transmissivities are also visualised as a function of depth in Figure 5-41, which shows values in both 2008 and 2010.

Figure 5-40. Zones HZ21 (brown) and OL-BFZ021 and fracture transmissivities, view towards east.

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

126

HZ21

KR01

KR02

KR04

KR05

KR06

KR07

KR11

KR12

KR19

KR29

KR40

KR43

KR01

KR02

KR04

KR05

KR06

KR07

KR11

KR12

KR19

KR29

KR40

KR43

KR47

300

400

500

600

700

800

900

1000

-10 -9 -8 -7 -6 -5 -4 -3log T (m2/s)

Dep

th (m

)

T 2008T 2010

Table 5-7. Drillhole depth intervals for the zone and for transmissivity (T) depth ranges, defining method applied for T depth ranges (cf. Chapter 2.4.1), and drillhole specific transmissivities of zone HZ21.

HZ21 Zone intersection, m T depth range, m T, m2/s log T Note OL-KR01 610.3 619.2 593 649 1 1.5E-06 -5.8 1) 2) OL-KR02 595.8 613.0 568 643 1 5.0E-07 -6.3 1) OL-KR04 756.8 764.2 750 820 1 1.2E-08 -7.9 OL-KR05 465.5 485.5 460 510 1 1.3E-07 -6.9 OL-KR06 473.6 477.9 435 479.5 1 5.9E-08 -7.2 OL-KR07 689.5 711.6 685 724 1 OL-KR11 623.6 627.1 615 650 1 OL-KR12 651.3 672.4 630.5 695.5 1 3.8E-08 -7.4 OL-KR19 456.7 466.0 440 494 1 1.1E-07 -7.0 1) OL-KR29 776.9 781.7 775 786 1 1.0E-09 -9.0 3) OL-KR40 966.8 968.8 946.8 988.8 2 OL-KR43 339.6 343.3 319.6 363.3 2 7.1E-09 -8.1 OL-KR47 524.6 555.4 504.6 575.4 2 2.0E-09 -8.7 1) Measured T value divided into two zones 2) Based on long-term pumping tests 3) Highly uncertain

Figure 5-41. Measured transmissivities of zone HZ21. T 2008 refers to the transmissivities of the 2008 model and T 2010 to the current version.

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5.5.4 Zone HZ21B

The HZ21B zone was modelled to connect the observed high fracture transmissivities with planar orientation rather close to zone HZ21. The average orientation of zone HZ21B is 157/30° in terms of dip direction and dip. The geometry of the zone has not been changed since 2008. The 3D visualisation of the zone and the transmissivities are shown in Figure 5-42. The drillhole depth intervals for the zone and for transmissivity depth ranges, the defining method for the transmissivity depth range (cf. Chapter 2.4.1), and the measured drillhole specific transmissivities of zone HZ21B are shown in Table 5-8. The transmissivities are also visualised as a function of depth in Figure 5-42, which shows values in both 2008 and 2010.

Figure 5-42. Zone HZ21B (blue) and HZ21, and fracture transmissivities, view towards east.

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

128

HZ21

KR01

KR02

KR04

KR05

KR06

KR07

KR11

KR12

KR19

KR29

KR40

KR43

KR01

KR02

KR04

KR05

KR06

KR07

KR11

KR12

KR19

KR29

KR40

KR43

KR47

300

400

500

600

700

800

900

1000

-10 -9 -8 -7 -6 -5 -4 -3log T (m2/s)

Dep

th (m

)

T 2008T 2010

Table 5-8. Drillhole depth intervals for the zone and for transmissivity (T) depth ranges, defining method applied for T depth ranges (cf. Chapter 2.4.1), and drillhole specific transmissivities of zone HZ21B.

HZ21B Zone intersection, m T depth range, m T, m2/s log T Note OL-KR01 610.3 619.2 593 649 1 1.5E-06 -5.8 1) 2) OL-KR02 595.8 613.0 568 643 1 5.0E-07 -6.3 1) OL-KR04 862.9 864.9 842.9 884.9 2 7.6E-07 -6.1 OL-KR05 404.3 410.3 384.3 430.3 2 4.9E-08 -7.3 OL-KR06 393.3 400.3 373.3 420.3 2 4.0E-06 -5.4 OL-KR12 737.3 751.4 717.3 771.4 2 4.2E-07 -6.4 OL-KR19 456.7 466.0 440 494 1 1.1E-07 -7.0 1) OL-KR43 154.5 156.5 134.5 176.5 2 1.3E-07 -6.9 1) Measured T value divided into two zones 2) Based on long-term pumping tests

Figure 5-43. Measured transmissivities of alternative zone HZ21B. T 2008 refers to transmissivities in the 2008 model and T 2010 to the current version.

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5.5.5 Zone HZ099

Zone HZ099 covers the central area of geologically pronounced brittle deformation zone OL-BFZ099. Drillholes with a notable transmissivity have been included in zone HZ099. The zone was extended towards east to intersect drillholes OL-KR6 and -KR12 for the current model version.

The average orientation of zone HZ099 is 169/38° in terms of dip direction and dip. The 3D visualisation of the zone and the transmissivities are shown in Figure 5-44. The drillhole depth intervals for the zone and for transmissivity depth ranges, the defining method for the transmissivity depth range (cf. Chapter 2.4.1), and the measured drillhole specific transmissivities of zone HZ099 are shown in Table 5-9. The transmissivities are also visualised as a function of depth in Figure 5-45, which shows values in both 2008 and 2010.

Figure 5-44. Zones HZ099 (red) and OL-BFZ099 and fracture transmissivities, view towards east.

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HZ099 Zone intersection, m T depth range, m T, m2/s log T Note OL-KR01 525.9 527.9 490.0 545.0 1 6.0E-07 -6.2 OL-KR02 504.0 508.0 494.0 518.0 2 5.3E-09 -8.3 OL-KR05 278.0 284.0 249.0 304.0 1 6.2E-07 -6.2 OL-KR06 126.0 132.2 116.0 134.7 2 1.1E-06 -6.0 OL-KR12 579.7 585.6 567.5 602.5 1 4.5E-08 -7.3 OL-KR13 450.3 459.9 434.0 498.0 1 1.1E-06 -6.0 OL-KR13* 490.1 492.1 OL-KR19 253.0 261.0 230.0 265.0 1 1.7E-07 -6.8 OL-KR20 416.0 429.0 402.5 438.0 1 5.2E-07 -6.3 OL-KR20 468.0 470.0 458.0 480.0 2 4.5E-07 -6.3 *Not used for zone modelling

Figure 5-45. Measured transmissivities of zone HZ099. T 2008 refers to transmissivities in the 2008 model and T 2010 to the current version.

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5.5.6 Zone HZ001

Zone HZ001 is modelled to connect drillhole sections with an anomalous low head. The zone was extended towards east to intersect drillhole OL-KR6 for the current model version.

The average orientation of the zone is 165/28° in terms of dip direction and dip. The 3D visualisation of the zone and the transmissivities are shown in Figure 5-46. The drillhole depth intervals for the zone and for transmissivity depth ranges, the defining method for the transmissivity depth range (cf. Chapter 2.4.1), and the measured drillhole specific transmissivities of zone HZ001 are shown in Table 5-10. The transmissivities are also visualised as a function of depth in Figure 5-47, which shows values in both 2008 and 2010.

Figure 5-46. Zones HZ001 (orange) and OL-BFZ099 and fracture transmissivities, view towards east.

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HZ001 Zone intersection, m T depth range, m T, m2/s log T Note OL-KR05 202.6 206.6 202.6 206.6 3 8.0E-06 -5.1 OL-KR06 134.7 136.7 134.7 136.7 3 5.9E-06 -5.2 OL-KR13 362.4 364.4 362.4 364.4 3 5.9E-08 -7.2 OL-KR19 202.0 214.0 202.0 214.0 3 1.2E-06 -5.9 OL-KR33 150.2 152.2 150.2 152.2 3 3.5E-06 -5.5 OL-KR43 58.0 60.0 58.0 60.0 3 3.2E-06 -5.5

Figure 5-47. Measured transmissivities of zone HZ001. T 2008 refers to transmissivities in the 2008 model and T 2010 to the current version.


OL-BFZ021 and -BFZ099 are moderately dipping thrust faults with an approximate dip of 20 – 40° towards south – southeast. Both fault zones are geologically well-pronounced, the fault core being well-developed and characterised by abundant fracturing, clay-filled fractures and slickensides, alteration and varying amounts of

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incohesive fault breccia and fault gouge. In OL-BFZ021, the thickness of the fault core varies from 1 to 8 m, the average thickness being approximately 4 m. The fault zone is intersected by 16 drillholes, and in 14 of them, the zone is fixed to a mapped brittle fault intersection. In OL-BFZ099, the thickness of the fault core varies from 1 to 13 m, the average thickness being 5 m. The fault zone is intersected by 16 drillholes, and in 14 of them, it is connected to a mapped brittle fault intersection.

The majority of the core intersections fall into the RiIII-category of the RG-classification, i.e. the Finnish bedrock classification system for construction purposes, but a few intersections features also RiIV and RiV sections. This corresponds to the variation in the relative proportions of fault breccia and fault gouge, fault breccia being the most common type of fault rock. The zone shows evidence of recurrent movements within the brittle regime, as ductile and semi-ductile precursors are in many drill cores overprinted first by welded fractures and cohesive breccias and later by younger fractures. The ductile thrust faults with a reverse dip-slip movement were reactivated in brittle deformation parallel to the previous direction but this time as normal faults (Aaltonen et al. 2010).

The thickness of fault zone OL-BFZ099 (core zone plus influence zone) is on average about 44 m but varies between 11 and 103 m in different drillholes. Characteristic features of the influence zone include an abundance of slickensides, pervasive illitisation, kaolinisation and sporadic occurrence of fracture-controlled sulphidisation and, in many cases, subsidiary fault core sections. The thickness of the influence zone of OL-BFZ021 is on average 42.9 m but varies between 75 m and 11 m. In general, the upper influence zone is somewhat thicker than the lower one.

OL-BFZ021 and -BFZ099 are considered to be two splays of one single fault, combining into a single zone in the central part of the site volume. Upper splay OL-BFZ099 has been extended towards SE on the basis of 3D seismic data. The modelled geometry is supported by the HIRE seismic reflection survey (Kukkonen et al. 2010) (cf. also Appendix II of Aaltonen et al. 2010). The zone is also extended to the bounding lineaments demarcating the whole site in the E, SE, SW and W.

Zones HZ001 and HZ021B have no correspondence in the brittle deformation model.

5.6 Modelling of zone HZ146

The Liikla Shear Zone is one of the major ductile sub-units interpreted on Olkiluoto Island, located as a boundary feature between CTU and STU. LSZ is the northernmost part of STU. Brittle fault zone OL-BFZ146 is modelled to follow LSZ and high fracture transmissivities seem to be related to the fault zone.

Following the hypothesis of the effect of the tectonic units on the hydrogeological properties of the bedrock, zone HZ146 is assessed to only have a weak hydraulic connection with e.g. the HZ19 and HZ20 zones located within CTU. So far, hydraulic connections have not been studied due to lack of packed-off drillholes and pumping tests within STU. The 3D visualisation of the HZ146 zone and corresponding zone OL-BFZ146 is shown in Figure 5-48.

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Figure 5-48. Zones HZ146 (lilac) and OL-BFZ146 and fracture transmissivities, view towards east.

5.6.1 Background

Zone HZ146 replaces zone HZ004. Zone HZ004 was introduced in the hydrogeological model in 2006 (Ahokas et al. 2007). The ground surface intersection of zone HZ004 followed a probable structure R7 (Saksa et al. 1993), which was based on a geophysical seismic refraction survey and Slingram measurements, and lineament interpretation. Conceptually the zone followed the average orientation of the structural geological F3 axial plane. Dip was based on several geological indications of a possible sub-vertical zone south and south-east of the ONKALO. The hydrogeological interpretation of zone HZ004 was based on indirect observations and its drillhole intersections were assessed highly uncertain (Ahokas et al. 2007, Vaittinen et al. 2009b). However, the modelling of the tectonic sub-units supported the existence of a structural geological boundary, but the orientation was uncertain until results of the seismic HIRE survey were available. GSM 2.0 (Aaltonen et al. 2010) describes brittle fault zone OL-BFZ146 following moderately dipping LSZ. Because all of the old drillhole intersections were removed due to changed dip, and in order to apply a uniform naming convention with GSM, zone HZ004 was renamed HZ146.

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The modelling of zone HZ146 is based on brittle fault zone OL-BFZ146, which follows the major ductile shear zone LSZ (Aaltonen et al. 2010). High or moderate fracture transmissivities are connected with the zone in each of the drillhole intersections, cf. Table 5-11. None of the intersected drillholes are packed-off; hydraulic connections cannot therefore be studied yet. More information of the hydraulic connections will be available when hydrogeological investigations, e.g. pumping tests, will be started in the eastern part of the site.

As described in the previous Chapter, the results of the seismic HIRE survey support the interpretation of the zone (Figure 5-49). In addition, the HZ146 zone is strongly supported by geophysical Mise-à-la-masse measurements (Figure 5-50). As in the case of the hydrogeological HZ20 zones, similar kind of hydrological and geophysical properties seem to be connected with the HZ146 zone, also.

Figure 5-49. Zone HZ146 and a detail of the seismic HIRE profile, view towards northeast. View from above to illustrate the location of the profile. The zone is cut in front of the profile. Explanation for the seismic data is given in Chapter ��.

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Figure 5-50. Zone HZ146, interpreted Mise-à-la-masse conduits, and fracture transmissivities, view towards west. View from above to illustrate the location of the conduits.

5.6.3 Zone HZ146

The HZ146 zone combines the high and moderate fracture transmissivities observed in close vicinity of the major ductile LSZ shear zone and corresponding brittle fault zone OL-BFZ146.

The average orientation of the zone is 161/29° in terms of dip direction and dip. The drillhole depth intervals for the zone and for transmissivity depth ranges, the defining method for the transmissivity depth range (cf. Chapter 2.4.1), and the measured drillhole specific transmissivities of zone HZ146 are shown in Table 5-11. The transmissivities are also visualised as a function of depth in Figure 5-51.

Compared with e.g. the OL-BFZ020 zones, the lengths of the drillhole-specific geological influence zones determined for OL-BFZ146 are notably shorter and the transmissive fractures included in the HZ146 zone are not located within the influence zones. Also, the zone-specific hydrogeological influence zone was assessed to be more uncertain due to a smaller number of transmissive fractures than drillhole-specific influence zones, and for this reason the latter method was applied for zone HZ146.

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HZ146 Zone intersection, m T depth range, m T, m2/s log T Note OL-KR27B 9.3 11.3 9.3 18.1 3 1.8E-05 -4.7 OL-KR40B 4.9 6.9 4.9 6.9 3 6.3E-05 -4.2 OL-KR45 119.6 121.6 119.6 121.6 3 4.7E-06 -5.3 OL-KR49 349.1 376.6 349.1 376.6 3 4.6E-08 -7.3 OL-KR50 438.8 448.0 438.8 448.0 3 1.4E-07 -6.9 OL-KR51 434.4 450.7 434.4 455.5 3 2.1E-06 -5.7 OL-KR51* 467.4 469.4 465.0 469.4 3 2.6E-06 -5.6 OL-KR52 405.2 427.4 405.2 427.4 3 2.0E-06 -5.7 1) *Not used for zone modelling 1) Based on indirect result

Figure 5-51. Measured transmissivities of zone HZ146.

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5.6.4 Corresponding brittle fault zone

OL-BFZ146 is the brittle portion of the Liikla shear zone (cf. Chapter 4.1). It is a moderately dipping, listric fault zone with an approximate orientation of ca. 155 – 165/30 – 60º. The modelled dip of the fault is at its steepest (60º) near the ground surface but becomes gentler with depth (Aaltonen et al. 2010).

The interpretation of zone OL-BFZ146 is based both on geological mapping data and on geophysical surveys. A ground surface intersection has been detected in a couple of outcrops and in investigation trench OL-TK14, where the zone is characterised by strongly foliated, pervasively altered and weathered veined gneiss. The mesosome is totally chloritised and hematised and the neosome is kaolinitised and illitised (Nordbäck 2007). Most foliation planes are weathered open, which gives the rock a densely fractured look.

The upper parts of drillholes OL-KR27, -KR40, and -KR45 included in OL-BFZ146 are highly fractured with numerous RiIII – RiIV zones. Fracture fillings are mainly clay, chlorite, illite, graphite, calcite and pyrite. Ca. 68 % of the fractures are reported to have clay fillings. In OL-KR45, the intersection shows the same degree of chloritisation and sulphidisation as the wall rock, but is conciderably more illitised than the surrounding rock. The outer borders of the intersection are defined by the lack of slickensided/clay-filled fractures and the weakening of illitisation. The zone has also been fixed to highly fractured sections in drillholes OL-KR49 and -KR50, showing slickenside fractures, alteration and indications of older semi-brittle deformation under the brittle fault zone.

Geophysically the zone can be observed by several methods. On the ground surface, the zone is located within a distinct magnetic minimum, and also electromagnetic anomalies. Furthermore, the HIRE seismic reflection survey (Kukkonen et al. 2010) indicates a reflector that coincides with this zone. The southeastern part of the zone is therefore constructed according to the HIRE reflector.


The modelling of zone HZ008 is mostly based on geophysical measurements and only two drillhole intersections located at a distance of more than 1 000 m from each other are connected to the zone. In comparison with other HZs, the interpretation of the HZ008 zone is therefore more uncertain. The 3D visualisation of the zone is shown in Figure 5-52.

This intersection was not modelled in GSM version 2.0 because of lack of structural geological mapping data but will be included in the forthcoming up-to-date version 2.1 of the GSM.

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Figure 5-52. Zone HZ008 and fracture transmissivities, view towards northeast.

5.7.1 Background

Zone HZ008 was first introduced as structure RC in 1991 (Ahokas & Äikäs 1991). The modelling of the zone was based on the access tunnel intersection of the operating waste repository (VLJ) and data from VLJ drillhole YD18. The zone was named R8 in the first version of the bedrock model in 1993 (Saksa et al. 1993). Horizontal seismic profiling (HSP) provided supporting results in 2001 (Cosma et al. 2003). The extension of the zone towards east was limited to not intersect drillhole OL-KR1 in 2001 (Vaittinen et al. 2001). The zone was reported as RH8 in 2003 (Vaittinen et al. 2003) and as HZ008 in 2006 (Ahokas et al. 2007). An almost 70 m section of densely fractured rock containing both clay-filled fractures and clay structures in drillhole OL-KR43 coincided with zone HZ008. For the previous 2008 model, the zone was extended to intersect both the northern and the southern bounding lineament and down to -2 000 m.


The dip of the zone HZ008 was slightly changed to fit with the results of wide-band EM soundings and with seismic HIRE anomaly (cf. Figure 5-53). Three electrically

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conductive zones were detected close to drillhole OL-KR43 by the electromagnetic Gefinex 400S survey. The survey was carried out in 1994 (Jokinen et al. 1995) and the data was re-modelled in 2004 – 2005 for geological modelling purposes. The re-modelled results from Profile 1524750E are shown in Figure 5-53.

The uppermost conductive zone coincides with brittle deformation zone OL-BFZ099 (Aaltonen et al. 2011) and the zone below it coincides with hydraulically conductive zone HZ21. These two zones were also detected by the Mise-à-la-masse surveys (Ahokas & Paananen 2010). The lowermost conductive zone coincided quite well with the HIRE results and the modelled hydraulically conductive zone HZ008.

The drillhole section of HZ008 in OL-KR43 is a polyphasically deformed intersection with strong ductile shearing followed by old welded brecciation and finally faulting (slickensides) and fracturing. Graphite-bearing fracture surfaces and fillings occur, and in places also pyrrhotite-filled fractures and pyrrhotite networks. Illitisation and a network of calcite veins occur, as well.

Figure 5-53. Modelled zone HZ008 (green), modelling results of wide-band EM soundings, and a detail of the seismic HIRE profile, view towards northeast. View from above to illustrate the location of the data. The zone is cut in front of the profile. Explanation for the seismic data is given in Chapter ��.

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5.7.3 Zone HZ008

Zone HZ008 is modelled to explain drillhole observations and to describe the interpreted geophysical anomalies located between VLJ and the investigation site.

Current average orientation in terms of dip direction and dip is 123/34° down to -1 350 m and 127/26° below that depth. The drillhole depth intervals for the zone, the defining method for the transmissivity depth range (cf. Chapter 2.4.1), and the measured drillhole specific transmissivities of zone HZ008 are shown in Table 5-12.

Transmissivity in drillhole OL-KR43 is based on indirect results assuming that the difference between the total pumping rate (PFL) and the sum of fracture specific flows measured between 40 and 566 m along the drillhole is flowing from the HZ008 zone intersection (572-593 m). The difference is in the order of one litre/min, which corresponds to a transmissivity in the order of 1·10-6 m2/s by the used drawdown. As reported in Ahokas & Äikäs (1991), the transmissivity measured in VLJ drillhole YD18 is in the order of 1·10-5 m2/s.


HZ008 Zone intersection, m T depth range, m T, m2/s log T Note OL-KR43 571.6 592.9 571.6 592.9 3 1.0E-06 -6.0 1) VLJ-YD18 1.0E-05 -5.0 1) Based on indirect result


Zone HZ039 is introduced in the current version of the model. The zone has only one intersection in drillhole OL-KR29 and the geometry of the zone is therefore uncertain. Despite the uncertain geometry, zone HZ039 is modelled because transmissivity exceeded the applied limit value described in Chapter 3.2 and the intersection is located below the planned repository at a depth of -525 m and may thereby form a flow path from the repository level to the ground surface or for the upconing of saline groundwater. The orientation of the zone is based on repository-scale brittle fault zone OL-BFZ039 located ca. 15 m above the high transmissivity section in drillhole OL-KR29. The 3D visualisation of the HZ039 zone and brittle fault zone OL-BFZ039 is shown in Figure 5-54.


Zone HZ039 is located within monitoring section L3 in drillhole OL-KR29, which has been packed-off since January 2006. No indications of pressure responses caused by the construction of the ONKALO have been seen; instead, the head seems to follow sea level variation (cf. Figure 5-55). The determined coefficient of the effect of sea level variation is 0.3580 while the highest coefficient in deep drillholes is 0.4797 and the mean value is 0.2498 (Vaittinen et al. 2010a). The zone has therefore been modelled to intersect the southern bounding lineament to connect the zone to the sea.

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Figure 5-54. Zone HZ039 (red), corresponding brittle fault zone OL-BFZ039, and fracture transmissivities, view towards north.

A total of three highly fractured sections are located between the depths of 540 and 580 m along drillhole OL-KR29. OL-BFZ039 and -BFZ024 are modelled to the two upper sections, at 533.0-548.55 m and 556.76-560.3 m, respectively, and high transmissivity occurs in the lowest section at 565.62 – 569.6 m, modelled as brittle joint zone KR29_BJI_56562_56960 in GSM v2.0 (Aaltonen et al. 2010). OL-BFZ039 was assessed to be a main fault zone due to the high number of slickensided fractures, and its orientation has been used in the modelling of HZ039, although the orientation of fractures in the HZ-zone is different from that of BFZ. In GSM version 2.0 (Aaltonen et al. 2010), the zone has been modelled to intersect drillhole OL-KR7 at a drillhole length of 473.92 m. However, the results of geophysical Mise-à-la-masse measurements (Ahokas & Paananen 2010) suggest a somewhat gentler orientation, which is also more typical of the hydrogeological zones at the site. Following the gentler orientation, the intersection in drillhole OL-KR7 would be at a depth of 410 – 420 m, where fracture transmissivities in the order of magnitude of 1·10-9 m2/s occur. HZ039 has not yet been extended to drillhole OL-KR7, but will be reassessed in the next modelling campaign.

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Figure 5-55. Head diagrams of drillhole OL-KR29 and sea level variation. Observation levels L1 – L3 do not show hydraulic connection to ONKALO, levels L4 – L6 are modelled to belong to the HZ20 zones, and levels L7 and L8 to the HZ19 zones.

5.8.2 Zone HZ039

Zone HZ039 is modelled to the observed high fracture transmissivities located below the planned repository depth. Depending on orientation and dimensions, the zone may intersect the repository and possibly form a hydraulic connection between the repository and the ground surface or a flow path for upconing of saline groundwater.

Current average orientation in terms of dip direction and dip is 126/56°. The drillhole depth intervals for the zone and for transmissivity depth ranges, the defining method for the transmissivity depth range (cf. Chapter 2.4.1), and the measured drillhole specific transmissivities of zone HZ039 are shown in Table 5-14.


HZ039 Zone intersection, m T depth range, m T, m2/s log T Note OL-KR29 565.5 570.0 565.5 570.0 3 6.4E-06 -5.2

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5.8.3 Corresponding brittle deformation zones

Brittle fault zone OL-BFZ039 is a repository-scale fault zone with a dip direction/dip of 125/56° (Aaltonen et al. 2010). It has been fixed to a brittle fault intersection in OL-KR29 at 533.00- 548.55 m (core zone at 543.8 – 546.4 m) and to a single fault in OL-KR7 at 473.92 m. The intersection exhibits 61 fractures, with a dip direction towards the SE with a moderate dip. The average fracture frequency within the zone is 9.3 fractures/m. The rock is more fractured in section 543.80-547.12 m (37 fractures, i.e. ca. 11 fractures/m). The intersection has 27 fractures with a slickenside surface (45 % of all fractures), 13 of them located in the presumed core section of the fault zone. The slickensided fractures have a striation direction varying from the SE to the SW with a moderate plunge. The intersection contains a few old and welded fractures with calcite and pyrite infillings, especially in pegmatitic granite. However, most of the fractures (73 %) in the intersection contain clay infillings, and several of them kaolinite and illite. 65 % of the fractures have chlorite-infillings. There are no indications of water flow in the flow measurements.

Brittle fault intersection OL-BFZ024 at 556.76-560.3 m in OL-KR29 contains a few old and welded fractures with calcite infillings. Some of the fractures contain kaolinite and illite infillings. These fractures show signs of water conductivity and some of them (559.86, 559.89 and 559.92 m) also have green-grey clay infillings. There is, however, no indication of water flow in the flow measurements. The intersection has 32 fractures, which are mainly gently dipping to the E and N.

Brittle joint zone intersection KR29_BJI_76562_76960 (Aaltonen et al. 2010) at the actual location of HZ039 contains some old and welded fractures with calcite infillings that have been partly opened during drilling. The intersection contains 42 fractures and the middle part of it (567.42-569.02 m) is intensely fractured and contains 25 fractures. About 74 % of the fractures are calcite-bearing, and about 35 % of the fractures containing grey clay infillings and accordingly, the whole section shows signs of water conductivity. This can also be observed in the flow measurements. The fractures in the core section are striking NW-SE, NE-SW and N-S with gentle dip towards the NE, NW and W, respectively.

These three brittle deformation zones can be considered to form one large deformation zone consisting of the main fault zone (OL-BFZ039), the subsidiary fault (OL-BFZ024) and the water conductive joint zone (KR29_BJI_76562_76960) within the lower influence zone. That the water flow is concentrated to the influence zone and not to the main fault zone is in accordance with the fault zone models and field measurements, which have shown that water conductivity can be many orders of magnitude greater within the influence zone than in the core zone (cf. Caine et al. 1996, Gudmundsson 2001).

5.8.4 Uncertainties

Obviously both the orientation and the dimensions of zone HZ039 are highly uncertain due to only one modelled drillhole intersection. According to the typical properties of the HZs in Olkiluoto, hydraulic connections coincide with electrical connections. The drillhole intersection of zone HZ039 is interpreted to have an electrical connection to

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drillhole OL-KR7 at the depth where possible hydrogeological zone HZ056 is interpreted (cf. Chapter 5.11.2). However, the transmissivity of HZ039 is several orders of magnitude higher than that of the other HZ056 drillhole intersections and the drawdown visible within zone HZ056 due to leakage into ONKALO has not been seen in drillhole OL-KR29 so far.

5.9 Zone OL-BFZ100

5.9.1 Background

Zone OL-BFZ100 was introduced in GSM version 0 (Paulamäki et al. 2006) for the first time. In GSM version 1.0, applied as a background model for hydrogeological structure model 2008, the zone was classified as a repository-scale feature. In current GSM version 2.0, the size of the zone was enlarged and it was moved to the site-scale category.

5.9.2 Description of brittle fault zone

OL-BFZ100 is a steeply dipping fault zone with an approximate orientation of 098/67º. Initially the fault had been observed in the geological surface mapping of investigation trench OL-TK11 carried out for the construction of the drill-core storage hall near the ONKALO tunnel. It is also observed in investigation trench OL-TK7 on the ground surface and at seven locations in the ONKALO access tunnel, and it is intersected by 10 drillholes. Due to these numerous intersections, the geometry of OL-BFZ100 is rather well known. It is also supported by geophysical Mise-à-la-masse results from the ground surface to ONKALO access tunnel (Aaltonen et al. 2010).

The fault zone has of a clearly definable core and a transition zone, the core having a varying width of 0.15 to 2 metres and in places strongly developed schistose fabric with associated slickensided surfaces. Quartz, pyrite, chalcopyrite, graphite, galena and talc mineralisations can be observed within the fault core. Pyrite mineralisation occurs within cavities associated with quartz-filled tension veins. Chalcopyrite seems to be associated with calcite-filled fractures/tension veins. In some drillhole intersections, pervasive or fracture-controlled illitisation is related to the fault. The fault-related alteration forms up to 4 m wide zone around the fault core (Pere 2009).

Based on the detailed structural geological mapping and K-Ar age determinations, Pere (2009) has determined three brittle deformation phases after the formation of ductile precursor at ca. 1.8 Ga. In the first brittle phase at ca. 1.55 Ga, the existing ductile fault was reactivated as a normal fault, forming a cohesive breccia cemented by hydrothermal minerals related to the intrusion of the Eurajoki rapakivi stock. In the subsequent phase at ca. 1.26 Ma, the zone was reactivated as a strike-slip fault with a formation of illite-bearing fault gouge and incohesive breccia. In investigation trench OL-TK11, the fault shows an apparent sinistral sense of movement, the displacement being 2.1 m (Mattila et al. 2007). In the third phase, overprinting vertical lineation formed on some fracture surfaces.

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5.9.3 Hydrogeological properties

No modifications have been made to the zone and therefore the same label for the zone is applied in the hydrogeological structure model as in the brittle deformation model. Hydrological properties have strong variation along zone OL-BFZ100. High fracture transmissivities are observed in the drillhole intersections connected to the zone close to the ground surface. It is assessed that probably high transmissivities in these drillholes are related either to the HZ19 zones (e.g. in drillhole OL-KR28) or to local features characteristic of near surface bedrock. Some minor leakages at ONKALO intersections have been measured in probe holes TR1812, TR2481, TR2917 and transmissivities based on these leakages are shown together with drillhole values in Figure 5-56. The transmissivities found in probe holes support the transmissivities determined in drillholes. Drillhole depth intervals and drillhole specific transmissivities are listed in Table 5-14. Due to the uncertainty related to high drillhole transmissivities within the near surface bedrock, values in drillholes OL-KR26, -KR28, and -KR34 (Figure 5-56) have been taken into account with remarks in the parameterisation of the zone (cf. Chapter 7). Geological influence zones have not been determined for zone OL-BFZ100.

An exception to typical ONKALO intersections occurred at the intersection of chainages 2929.2 – 2930.1 m, where a total of ten dripping leakages are mapped along a ca. 10 m tunnel section (Vaittinen et al. 2010a). When the tunnel was excavated through zone OL-BFZ100 in May 2008, the head in nearby monitoring section OL-KR23 L2 decreased below the measuring depth, i.e. below ca. 40 m. Before the head decreased, head on monitoring level L2 followed the head within the HZ20 system. Possibly level L2 is connected to a local branch of the HZ20 system and leakage into the ONKALO tunnel occurs along the OL-BFZ100 zone (cf. Figure 5-56).

The sub-vertical OL-BFZ100 zone intersects the main hydrogeological systems HZ19 and HZ20 in the ONKALO area. A possible blocking effect on the groundwater flow along the sub-horizontal hydrogeological systems was studied based on interpreted pressure responses in Vaittinen & Pentti (2011), but no indications were observed of such a phenomenon.

147

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

Figure 5-56. Zone OL-BFZ100 and fracture transmissivities, view towards north.

Table 5-14. Drillhole depth intervals for the zone and for transmissivity depth ranges and drillhole specific transmissivities of zone OL-BFZ100.

BFZ100 Zone intersection, m T depth range, m T, m2/s log T Note OL-KR22 337.7 340.5 337.7 340.5 1.0E-10 -10.0 OL-KR23 372.5 373.0 372.5 373.0 1.0E-10 -10.0 OL-KR25 216.5 222.1 216.5 222.1 1.0E-10 -10.0 OL-KR26 95.8 98.3 95.8 98.3 3.0E-05 -4.5 1) OL-KR28 177.02 178.02 161 189 1.8E-06 -5.8 2) OL-KR34 48.4 53.8 48.4 53.8 4.6E-06 -5.3 OL-KR37 56.2 57.5 56.2 57.5 3.4E-07 -6.5 OL-KR42 183.0 198.8 183.0 198.8 2.2E-09 -8.7 OL-PH01 151.6 154.3 151.6 154.3 n.a. ONK-PH04 27.1 29.6 27.1 29.6 2.3E-08 -7.6 1) Based on indirect result 2) Measured T value divided into two zones

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BFZ100

TR2917

TR2481

TR1812

PH04

KR42

KR37KR34

(uncertain)

KR28(uncertain)

KR26(uncertain)

KR25

KR23

KR22

0

50

100

150

200

250

300

350

400

-10 -9 -8 -7 -6 -5 -4 -3log T (m2/s)

Dep

th (m

)

Figure 5-57. Measured transmissivities of zone OL-BFZ100.

5.10 Fracture properties and lithology of zones

The fracture properties and the lithology of the hydrogeological zones have been studied based on drill core data. The fracture properties within the zones are analysed utilising the detailed fracture data and as a result the differences between the zones and the averagely fractured rock as well as between the transmissive fractures and the dry fractures are reported. Detailed fracture data was available from drillholes OL-KR1 � -KR50 and lithological data from drillholes OL-KR1 – -KR55. The results related to fracture data are shown in Table 5-15 and the results related to lithology in Table 5-16. The descriptions of the lithological units are given in Aaltonen et al. (2010).

The intersections of the hydrogeological zones (HZ001, HZ099, HZ19A, HZ19B, HZ19C, HZ20A, HZ20B, and HZ21) contain on average 1.71 fracture filling minerals in a single fracture (incl. clay), which is similar to the value based on all drill core data in Olkiluoto (1.63 minerals in a fracture). Hydraulic conductive fractures in these zones contain 1.97 fracture minerals (incl. clay) and dry fractures contain 1.78 minerals (incl. clay) on average. Fractures without hydrological data contain 2.01 minerals (incl. clay) on average. Fracture frequency outside the major zones on the Olkiluoto site is 2.3 fractures per metre. In hydraulic zones, frequency varies between 3.1 (HZ001) and 9.7

149

(HZ21B), i.e. it is significantly higher than in the surroundings. The rock is more conductive but also non-conductive fractures are much more frequent inside the zones.

Approximately 11 % of all the fractures are slickensided single faults in Olkiluoto drillcore fracture data. In the hydraulic zones, this proportion varies a lot. In zones HZ001, HZ008, HZ21, HZ21B and HZ099, the amount of slickensided fractures is up to three times as high as in average rock. Zones HZ19 and HZ20, on the other hand, have much less slickensided fractures than Olkiluoto drillholes on average. This is due to the nature of the corresponding brittle fault zones. As explained earlier in the case of HZ19, many of the drillhole intersections connected to the zone are lacking in proper fault intersections, indicating that the fault zone is not uniform but segmented into several separate fault zones, which do not show in every drillhole but may be connected via step-over zones. About one third of all the fractures in Olkiluoto drill cores studied so far contain calcite fillings. The calcite fracture percentages are somewhat higher in hydraulic zones (42 % on average), with the exception of HZ008 and HZ039, in which the amount is twice as high as on average. The fillings are on average somewhat thicker in the fractures inside the zones than outside the zones. The amount of sulphide-filled fractures is highest in the HZ19 zones, which are located near the surface and in this rock volume they are strongly affected by hydrothermal sulphidisation. There are much less sulphide fractures in the zones located deeper in the bedrock, such as HZ21 and HZ099. However, zone HZ008 has the highest amount of sulphides, although it is located deep in the bedrock, at 572-593 m in drillhole OL-KR43. Clay fillings are abundant in all zones but especially in HZ146, HZ001, HZ099, HZ21, HZ001 and HZ19A. Except for HZ001 and HZ146, the proportion of clay is not, however, much above the average. On the other hand, in HZ19C, HZ20B, HZ21B and HZ039, the amount of clay is much smaller than on average.

Lithological units are mainly parallel to foliation on the Olkiluoto site. Foliation controls fracturing and the main fault zones are also close to the foliation direction. Hence, lithology varies less inside the major zones than on the whole site, although the zones are very extensive. E.g. the TGG content is very high in zone HZ001 and the MGN content in HZ008 compared with the total proportion of TGG and MGN on the site. Some zones follow the lithological layers and contain high amounts of fine-grained gneiss inclusions such as QGN. E.g. zone HZ20B has a high amount of gneisses (QGN, MGN, MFGN), which are usually observed as metre-scale inclusions.

150

Table 5-15. Fracture densities (P10) and amounts of major fracture filling minerals in hydraulic zone intersections and in drillholes OL-KR1 – -KR50.

ZONE ID

TOTAL LENGTH m

NUMBER OF FRACTURES

P10 1/m

SLICKEN-SIDED %

CARBO-NATES %

CARBO-NATE THICK-NESS mm

SULPHIDES%

SULPHIDE THICK-NESS mm

CLAY%

CLAY THICK-NESS mm

HZ001 24.0 75 3.1 12.0 49.3 0.4 21.3 0.2 58.7 0.4 HZ008 21.3 275 12.9 30.5 65.8 0.4 47.6 0.5 46.2 0.4 HZ019A 131.1 611 4.7 3.8 28.0 0.5 45.9 0.3 50.7 0.4 HZ019B 64.6 340 5.3 8.4 31.3 0.4 45.4 0.3 43.9 0.4 HZ019C 108.6 547 5.0 6.8 28.0 0.4 42.4 0.3 39.7 0.3 HZ020A 97.2 531 5.5 7.4 37.3 0.5 36.7 0.25 40.6 0.2 HZ020B 111.1 898 8.1 7.2 42.4 0.6 25.8 0.3 38.5 1.3 HZ021 155.1 1098 7.1 21.5 40.5 0.35 22.4 0.2 55.9 0.3 HZ021B 66.5 646 9.7 12.2 45.1 0.6 21.8 0.2 30.8 0.3 HZ039 4.5 42 9.3 0 73.8 1.6 16.7 0.4 35.7 0.6 HZ099 58.7 506 8.6 19.6 41.7 0.5 21.5 0.2 52.8 0.4 HZ100 36.8 300 8.2 19.3 56.3 0.6 38.9 0.3 51.1 0.5 HZ146 83.2 728 8.8 15.1 38.6 0.6 37.4 0.4 67.6 0.4 KR1-50 25345.3 57821 2.3 10.6 35.4 0.4 31.3 0.3 51.2 0.4

Table 5-16. Lithology (Aaltonen et al. 2010) in hydraulic zone intersections and in drillholes OL-KR1 – -KR55.

ZONE ID VGN %

DGN %

TGG %

PGR %

MGN%

QGN %

MFGN %

KFP%

MDB %

CRUSH %

HZ001 17.9 73.8 8.3 HZ008 100.0 HZ019A 6.7 81.2 1.5 6.1 1.5 3.0 HZ019B 8.6 70.9 8.9 8.4 3.1 HZ019C 13.5 61.9 4.7 10.4 8.5 1.0 HZ020A 37.4 34.6 4.5 22.9 0.6 HZ020B 22.0 20.2 23.5 19.1 10.2 5.0 HZ021 67.9 12.2 6.5 12.2 1.2 HZ021B 54.3 17.1 12.8 8.2 2.8 4.8 HZ039 100.0 HZ099 51.0 20.2 28.1 0.7 HZ100 93.8 4.9 1.3 HZ146 32.9 43.8 7.0 3.7 1.2 11.4 OL-KR1-55 35.2 32.3 6.2 17.1 6.2 0.4 1.0 1.4 <0.1 <0.1

5.11 Possible hydrogeological zones

5.11.1 Site-scale BFZs

To assess uncertainties related to the observation and interpretation of hydrogeological features, all modelled site-scale BFZs in version 2.0 (Aaltonen et al. 2010) are parameterised for numerical modelling purposes. Possible flow routes may occur from the planned repository to the biosphere or enable upconing of saline groundwater or hydraulic connections to the sea.

151

A total of 13 modelled site-scale BFZs are considered to be possible hydrogeological zones in the hydrogeological structure model (cf. Table 5-17). Five of them have at least one drillhole intersection. The modelling of these BFZs has mainly been based on interpretation of geophysical investigation data. Site-scale BFZs are presented in Figure 3-1. From the geological modelling point of view, the confidence of interpretation varies from high to low. Depth dependent transmissivities have been determined for possible hydrogeological zones, cf. Chapter 7.

Table 5-17. Site scale BFZs considered to be possible hydrogeological zones.

Zone Confidence Drillhole intersections, m OL-BFZ175 High OL-KR09 547.74 549.23

OL-KR11 413.08 413.27 OL-KR42 297.99 298.36 OL-KR46 411.7 412.17 OL-KR47 220.87 221.5

OL-BFZ152 Medium OL-KR44 793.3 793.68 OL-KR45 68.89 69.16

OL-BFZ159 Medium OL-KR40 385.4 386.4 OL-BFZ160 Medium OL-KR45 176.02 180.51 OL-BFZ161 Medium OL-KR04 808.3 809.95 OL-BFZ147 Low - OL-BFZ148 Low - OL-BFZ149 Low - OL-BFZ150 Low - OL-BFZ155 Low - OL-BFZ157 Low - OL-BFZ158 Low - OL-BFZ169 Low -

5.11.2 Zone HZ056

Electrically conductive zone ONK56 was modelled according to the electromagnetic (Sampo/Gefinex 400S monitoring) and electric Mise-à-la-masse survey data in 2004 (Kemppainen et al. 2007). Zone ONK56 was in 2007 reported to intersect eight drillholes (cf. Figure 5-58). The geometry of the zone has not been updated but the transmissivity of the zone was reassessed in 2010 (cf. Table 5-18).

After the data freeze date at the end of May 2010, hydraulic connections along the zone were interpreted for the first time when inflow occurred through drilled pilot hole ONK-PH14. The zone is renamed as HZ056 and the geometry will be updated in the Olkiluoto Monitoring programme. Zone HZ056 is observed at the planned repository depth and may provide a flow path to the biosphere. The geological nature of this zone is still unknown and therefore it is not presented in the GSM 2.0 of the Olkiluoto site.

152

Figure 5-58. Zone HZ056 and fracture transmissivities, view towards north.

Table 5-18. Drillhole depth intervals for zone HZ056 and transmissivities.

HZ056 Depth range, m (2007) T, m2/s (2010)OL-KR1 345 350 5.00E-10OL-KR3 158 163 1.00E-10OL-KR4 484 497 1.00E-10OL-KR7 407 417 8.00E-09OL-KR10 432 433 1.00E-10OL-KR14 381 382 2.00E-10OL-KR25 571 578 6.00E-08OL-KR28 565 570 2.00E-09

Pressure and flow responses

The head in the monitoring sections included in zone HZ056 followed the head of the HZ20 system, when the excavation through the system started in July 2008, cf. HZ20 reference head in Figure 5-59. Probably a hydraulic connection to the HZ20 system is

153

caused by drillhole OL-KR25, where both zones are located in the same packed-off section. When the head in monitoring section OL-KR7 L1 decreased 20 m due to inflow along pilot hole ONK-PH10 in March 2009, it was assessed to be caused by a local feature due to the short distance between the section and the pilot hole. The inflow was 0.4 l/min. Looking at a longer period of head diagrams, the decrease rate changed in monitoring sections OL-KR4 L2 and -KR10 L3, as well. The response depended on the distance between inflow and the monitoring section and the transmissivity of the section.

Hydraulic connections along zone HZ056 were interpreted for the first time when inflow through pilot hole ONK-PH14 occurred. The pilot hole was drilled from chainage 4 313 m along the access tunnel during 4 – 9 June 2010. The first indications of drawdown were visible in monitoring sections OL-KR4 L2, -KR7 L1, and -KR10 L2 cf. Figure 5-59. When inflow through pilot holes ONK-PH16 and -PH17 occurred, drawdown in sections OL-KR1 L5 and -KR28 L1 was interpreted additionally. The pilot holes were drilled on 7 – 19 October 2010. In addition, the head started to decrease in the adjacent monitoring sections in drillholes OL-KR1 (L3-L4), -KR4 (L1), and -KR10 (L1-L2).

The possible extension of HZ056 intersects drillhole OL-KR40 at a depth of 790 m (cf. Figure 5-60) where flow and head changes were detected in connection with flow logging in the summer 2009 and 2010 (Sokolnicki & Pöllänen 2008, Vaittinen et al. 2010a, Vaittinen et al. 2011). The inflow of ca. 800 ml/h measured in spring 2006 changed into outflow in 2009 and outflow increased to over 400 ml/h in 2010. This kind of a change from inflow to outflow is a good indicator of a hydraulic connection to the sources of disturbance, which in this case are probably leakages in the intersections of HZ056 and the ONKALO. Head has in drillhole OL-KR40 at a depth of 790 m decreased from 0 m.a.s.l. in 2006 to a value of -2.5 m.a.s.l. in 2010, based on the flow logging data.

154

2843 3116 3121 3263 3376 3528 3660 3825 4059 4200 4313 4417 4560

-30-28-26-24-22-20-18-16-14-12-10-8-6-4-202468

10

1.1.08 1.1.09 2.1.10 3.1.11

Date

Hea

d, m

.a.s

.l.

0

220

KR01 L5 311.2-336.8 KR04 L2 481-585 KR07 L1 291-811 KR10 L3 396-430

KR25 L1 387-605 KR28 L1 516-525 KR01 L5 311.2-336.8 Man KR04 L2 481-585 Man

KR07 L1 291-811 Man KR10 L3 395-430 Man KR28 L1 516-525 Man ONKALO chainage

HZ20 reference headKR25 L1

ONK-PH10 (0.4 l/min)

Disturbed data removed

ONK-PH14 (0.8 l/min)ONK-PH17 (1 l/min)

Figure 5-59. Head diagrams of monitoring levels OL-KR1 L5, -KR4 L2, -KR7 L1, -KR10 L3, andKR28 L1, in which leakage along zone HZ056 caused the strongest drawdown.

155

Figure 5-60. The location of flow and head responses in OL-KR40 at a depth of 790 m probably caused by leakage into ONKALO along zone HZ056.

Geophysics

According to the Mise-à-la-masse survey results (e.g. Ahokas and Paananen 2010), the HZ056 zone is quite extensive. Table 5-19 shows the locations of electrical connections in different drillholes modelled from the Mise-à-la-masse data. The connections are visualised in Figure 5-61. The connections are mostly detected by two electrical earthings, one at a depth of 490 m in drillhole OL-KR4 and the other at a depth of 416 m in drillhole OL-KR7. So far, electrical connections to drillholes OL-KR40 and -KR44 located in the eastern area of Olkiluoto are uncertain because they are measured by the earthing in drillhole OL-KR40 at a depth of 791 m and this conductor has not yet been confirmed to belong to the HZ056 zone. The geometrical continuity of the conductors suggests a connection.

Zone HZ056 is located between zones HZ20B and HZ21. Each of these zones is electrically conductive and the Mise-à-la-masse survey results support the hydrogeological structure modelling. These zones can be detected in the 3D-seismic image presented in Figure 5-61.

156

Table 5-19. The electrical connections of the HZ056 zone detected in different drillholes by Mise-à-la-masse survey, uncertain connections in parenthesis.

Drillhole Depth range, m Drillhole Depth range, m OL-KR1 335 - 370 OL-KR29 530 - 570 OL-KR3 235 - 245 OL-KR33 100 - 140 OL-KR4 489 - 491 OL-KR38 520 - 530 OL-KR7 416 - 428 OL-KR39 305 - 325 OL-KR10 410 - 442 (OL-KR40 791) OL-KR11 440 - 500 OL-KR41 385 - 390 OL-KR14 374 - 392 OL-KR42 386 - 390 OL-KR15 323 - 353 (OL-KR44 795) OL-KR24 528 - 542 OL-KR46 495 - 505 OL-KR25 516 - 580 OL-KR47 310 - 400 OL-KR28 565 - 570

Figure 5-61. The location of zone HZ056 (green) according to the modelling of Mise-à-la-masse survey data and interpreted electrical conduits. One seismic reflection image section supporting the interpretation of the zone is presented. View towards northeast.

157

5.12 Bounding lineaments

At the first stage of the investigations carried out to find a site for the disposal of spent nuclear fuel, large-scale lineament data covering the whole country were used to characterise suitable rock blocks for further investigations. The lineaments bounding the Olkiluoto site in the south and in the north were originally determined during the study by Hakkarainen (1984). Since then, several revised lineament interpretations on different scales have been carried out in the area (Kuivamäki 2000, 2001, 2005, and Korhonen et al. 2005).

GSM version 2.0 (Aaltonen et al. 2010) introduces a modified geometry for the northern bounding lineament. An intersection with drillhole OL-KR47 has been interpreted and the lineament is currently described as brittle fault zone OL-BFZ214. Bounding lineaments, including zone OL-BFZ214, are visualised in Figure 1-1.

5.13 Summary and cross-sections of the model

Basic information on the geometry and transmissivity of the hydrogeological zones is listed in Table 5-20. The mean orientation, dimensions, depth range, approximate thickness, and minimum and maximum transmissivity as log(T) values are given.

A cumulative presentation of the occurrence of transmissive fractures in the bedrock and the hydrogeological zones is given in Figure 3-12.

Cross-section images of the model have been compiled. The following sections are presented: horizontal sections at levels 0 m (Figure 5-62), -300 m (Figure 5-63), -420 m (Figure 5-64), -520 m (Figure 5-65), and vertical sections south-north (A-A) (Figure 5-66) and southeast-northwest (B-B) (Figure 5-67). The locations of the vertical sections are shown in each of the horizontal sections.

Table 5-20. Basic data on the geometry and transmissivity of the hydrogeological zones. Zone OL-BFZ100 has the same geometry in both models.

Zone

HZ-model

Corresponding zone

BFZ-model

DipDir/Dip

(deg)

Dimensions

(m/m)

Depth range

(m.a.s.l.)

Thickness

(m)

Min logT

(m2/s)

Max logT

(m2/s) HZ001 168/30 585 / 1513 5 .. -325 3.5 -7.2 -5.1 HZ008 125/32 3730 / 4919 11 .. -2018 8.5 -6.0 -5.0 HZ19A OL-BFZ019A 144/6 966 / 1142 6 .. -118 4.3 -7.0 -3.8 HZ19B 151/16 765 / 932 -35 .. -269 2.7 -6.8 -3.9 HZ19C OL-BFZ019C 136/10 1230 / 1589 6 .. -313 3.3 -7.7 -4.0 HZ20A OL-BFZ020A 109/15 2068 / 1327 3 .. -491 3.8 -6.7 -4.3 HZ20B OL-BFZ020B 138/22 1736 / 1617 -105 .. -880 6.2 -6.3 -4.8 HZ21 OL-BFZ021 162/20 4158 / 8319 8 .. -1463 6.6 -9.0 -5.8 HZ21B 157/30 1707 / 1669 9 .. -1004 6.6 -7.3 -5.4 HZ039 OL-BFZ039 126/56 179 / 2457 -394 .. -655 5 -5.2 -5.2 HZ099 OL-BFZ099 169/38 890 / 880 6 .. -691 5.9 -8.3 -6.0 OL-BFZ100 OL-BFZ100 98/72 238 / 1248 10 .. -600 0.9 -10.0 -4.5 HZ146 OL-BFZ146 160/29 1308 / 2715 18 .. -627 8.9 -7.3 -4.2

158

F

igur

e 5-

62. H

oriz

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at le

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m.

159

F

igur

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63. H

oriz

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tion

at le

vel -

300

m.

160

F

igur

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64. H

oriz

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tion

at le

vel -

420

m.

161

F

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65. H

oriz

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at le

vel -

520

m.

162

F

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66. V

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al so

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163

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ure

5-67

. Ver

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164

165

6 HYDROGEOLOGICAL LOCAL-SCALE STRUCTURES

The observation of local-scale hydrogeological features is strongly biased. The observation is dependent on e.g. the location of and the distances between drillholes, whether the drillholes are open or packed-off, disturbances during flow condition measurements, and the location of monitoring sections in packed-off drillholes. In many cases, compared with site-scale features, hydraulic connections related to local-scale features are weaker. After the 2008 version, observations related to weak hydraulic connections have increased due to leakages into ONKALO. Compared with short-term field activities carried out in drillholes, e.g. pumping for PFL measurements and for groundwater sampling, leakage along the HZ20 system into the ONKALO since July 2008 has provided information on weak connections, where notably slow drawdown occurs. So far, the monitoring sections have mostly been located so as to cover the highest fracture transmissivities along a drillhole to investigate the most potential flow connections, and to a lesser degree fractures with low transmissivity. Due to the biased observation, information on weak hydraulic connections can be used for qualitative characterisation of the site and an assessment of the properties of local features. A deterministic local-scale structure model could be compiled only for limited volume close to the ONKALO.

Three kinds of local features are interpreted: 1) hydraulic connections between two or more drillholes enabling visualisation of the connections, 2) hydraulic connections between a zone and a drillhole, geometry is unknown, and 3) hydraulic connections between ONKALO and a drillhole, geometry is unknown.

As a result of a systematic analysis of the occurrence of anomalous fracture transmissivities (cf. Chapter 2.4.1), 22 out of 35 anomalous fractures were connected to site scale HZs. Three were connected to local-scale hydrogeological features and ten were included in the data on sparsely fractured rock (cf. Chapter 6.2).

6.1 Local-scale features

Hydraulic connections between two or more drillholes

In the 2008 model, local-scale features Local_1 – Local_6 were introduced, and site-scale zone HZ002 introduced in Ahokas et al. (2007) was classified as a local-scale feature (Vaittinen et al. 2009b). Short descriptions of the features and the interpreted drillhole intersections are given in the following Sections. Feature Local_6 described a local connection between the HZ20 system and drillhole OL-KR16. Zone HZ20A was enlarged to intersect drillhole OL-KR16 for the current model replacing feature Local_6. Zone HZ002 and features Local_1 – Local_5 are visualised in Figure 6-1. The drillhole intersections are shown in Appendix 1, labels refer to the feature id and to possible connections with site-scale zones.

166

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

HZ002

Local_3

Local_2

Local_1

Local_5Local_4

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

HZ002

Local_3

Local_2

Local_1

Local_5Local_4

Figure 6-1. The interpreted local zones, HZ002 (grey), Local_1 (red), Local_2 (yellow), and hydraulic connections Local_3, Local_4 and Local_5 (dark blue, green and light blue, respectively).

The interpretation of local zone HZ002 was based on hydraulic responses observed between drillholes OL-KR1 and -KR2, e.g. during the OL-KR1 pumping test in 1992 (Ylinen et al. 1992), and between OL-KR1, -KR2, -KR14, and -KR18 during the OL-KR14 and -KR18 pumping tests (Klockars et al. 2006). The orientation of the zone is 120/6°. The zone is located within CTU1, cf. Table 6-1. The zone has no correspondence in the brittle deformation model.

Table 6-1. Drillhole intersections of local feature HZ002. HZ002 Zone intersection, m

OL-KR1 62 66OL-KR2 84 88OL-KR14 94 98OL-KR15 72 75OL-KR16 79 80OL-KR17 67 70OL-KR18 77 81OL-KR32 79 87

167

Based on the pressure responses observed during the drilling of drillhole OL-KR32, a local zone Local_1 has been interpreted. An electrically conductive zone based on drillhole conductors OL-RES-001 (Paananen et al. 2007) supports the interpretation of this local hydrogeological zone. As is typical on the Olkiluoto site, the electrically conductive zone covers a larger area than the hydraulically conductive zone. In addition to the interpreted drillhole intersections (cf. Table 6-2), drillholes OL-KR2 and -KR13 are both electrically and hydraulically connected, but hydraulically connected depth sections cannot be determined. The zone is located within CTU1 and the orientation of the zone is 158/27°. The zone has no correspondence in the brittle deformation model.

The hydrogeological properties and hydraulic connections of local zones HZ002 and Local_1 can be assessed on the basis of monitored head data of adjacent drillholes OL-KR15 – -KR18. As an example, the head diagrams of drillhole OL-KR16 during packer malfunction in drillhole OL-KR22 are visualised in Figure 6-2.

Observation level L1 in drillhole OL-KR16 is connected to the HZ20 system and both the start and the end of the packer malfunction are visible as sharp pressure responses. Observation level L2 is interpreted to be connected to hydrogeological feature Local_1. The head diagram shows a connection to the HZ20 system, but the head is significantly higher than the HZ20 head. Support to the occurrence of Local_1 feature was obtained when drillhole OL-KR17 was packed off in November 2008. Head decreased in nearby drillhole sections OL-KR15 L3 and -KR16 L2 to the specific level. Before packing-off, head in open drillhole OL-KR17 followed the head in the HZ19 system (Vaittinen et al. 2010b). Also, the interpreted responses during the drilling of drillhole OL-KR32 supported the existence of the feature. Head on observation level OL-KR16 L3 follows smoothly the HZ19 head, but is somewhat lower. Observation level L3 is interpreted to be connected to hydrogeological zone HZ002. Observation levels OL-KR16 L4-L6 as well as levels -KR16B L1-L2 are connected to the HZ19 system.

The partially hydrogeological zone RH20C (Local_2 in 2008) was modelled in 2003 to intersect drillholes OL-KR2, -KR12, -KR13, and -KR19. The modelling of zone RH20C was based on VSP-reflectors, the anomalous zone thickness determined by fracture frequency, the coincidence of fracture and foliation data in drillhole OL-KR12, and planar geometry (Vaittinen et al. 2003). For the 2008 model, hydraulic observations related to RH20C were studied. Hydraulic connections were interpreted to all drillholes, but in drillhole OL-KR19, a hydraulically connected depth could not be determined, and the selected intersection is therefore based on geological similarity. A connection was observed between drillholes OL-KR12 and -KR42 during the drilling of drillhole OL-KR42. The interpreted zone is located within the modelled SDZ included in NTU. Drillhole intersections are given in Table 6-3. The dip direction and dip of the zone are 126/22°.

The intersection in OL-KR42 includes four modelled brittle fault zones: OL-BFZ041, -BFZ175, -BFFZ209, and -BFZ210 (Aaltonen et al. 2010). None of them have connections to other intersections of Local_2.

168

OL-KR16

KR16B_SFAILURE_L1

KR16_SFAILURE_L1

KR22_OPENKR22_OPEN

KR46 KR30 KR31

KR31KR36

KR52

KR35KR22KR52

KR51

KR52KR53

KR53KR51

KR49

KR14KR47_PAVE

KR47

TR3898

PH11_DRILL

TKU3745

KU2_3080_Phase-4KU1_3040_Phase-1

PP195PP187-198

PP187-198PP187-198

PP187-198

PP191PP191

PP193PP194PP194

PP196

PP196PP187-198

PP201PP216

PP201

3703 3776 3825 3877 3922

-15

-13

-11

-9

-7

-5

-3

-1

1

3

5

7

1.7.09 31.7.09 30.8.09 30.9.09 30.10.09

Date

Hea

d, m

.a.s

.l.

0

20

40

60

80

100

120

140

160

180

200

220

Prec

ipita

tion,

mm

/ In

flow

, l/m

in

KR16 L1 143-170.2 KR16 L2 113-142 KR16 L3 83-112 KR16 L4 63-82 KR16 L5 53-62 KR16 L6 40-52KR16B L1 21-35 KR16B L2 4.5-20 ONKALO LEAK DRILL CLPGWS PFL HTU PCK PMPTEST Sea LevelKR16 L1 143-170 Man KR16 L2 113-142 Man KR16 L3 83-112 Man KR16 L4 63-82 Man KR16 L5 53-62 Man KR16 L6 40-52 ManKR16B L1 21-35 Man KR16B L2 4.5-20 Man Reference fluctuation Precipitation ONKALO chainage Inflow ONKALO

Figure 6-2. Monitored head diagrams of drillhole OL-KR16 characterising the hydrogeological properties of the site-scale and local-scale features.

The drilling of drillhole OL-KR13 was carried out in 2001. Three sequential responses were observed in packed-off drillhole OL-KR2, which was the only packed-off drillhole at that time (Vaittinen et al. 2008b). The second response was connected to the aforementioned local feature (Local_2) and the third response is linked to site scale zone HZ099. The uppermost response Local_3 (cf. Table 6-4) has not been connected to other drillholes. It is located within SDZ.

Drillholes OL-KR4 and -KR8 were temporarily packed-off during the drilling of drillhole OL-KR24 in 2003. All other nearby drillholes were open at that time. The first response, Local_4, was only observed on observation level OL-KR4 L8 (40-62 m) when drilling reached the depth range of 75.9-84.8 m in drillhole OL-KR24 (Niinimäki 2003, Vaittinen et al. 2008b). Drawdowns during the long-term pumping test carried out in drillhole OL-KR24 in 2004 also support the model of local connections above 80 m (Vaittinen & Ahokas 2005). The drillhole intersections of local hydraulic connection Local_4 are given in Table 6-5.

A hydraulic response, Local_5, was observed in packed-off drillhole OL-KR11 L6 when drillhole OL-KR46 was drilled in 2007. The connected drillhole section was 132.2-136.2 m. In addition, Mise-à-la-masse measurements show an electrical connection between the same drillhole sections. The connection is located within SDZ. The intersection in OL-KR11 includes brittle fault zone OL-BFZ125 oriented 170/53°, which, however, has no connection to OL-KR46 (cf. Aaltonen et al. 2010).

169

Table 6-2. Drillhole intersections of local feature Local_1.

Local_1 Zone intersection, mOL-KR2 OL-KR12 94.7 96.7OL-KR13 OL-KR15 122.3 133.3OL-KR16 115.9 127.9OL-KR17 123.8 129.8OL-KR20B 8.8 10.8OL-KR32 51 53

Table 6-3. Drillhole intersections of local zone Local_2 (RH20C).

Local_2 Zone intersection, mOL-KR2 228.5 243.3OL-KR12 299.2 323.2OL-KR13 209.9 239.7OL-KR42 296.6 346.9OL-KR19 109.8 130.5

Table 6-4. Drillhole intersections of local hydraulic connection Local_3.

Local_3 Zone intersection, mOL-KR2 141 153OL-KR13 107.6 109.6


Local_4 Zone intersection, mOL-KR4 59.6 61.6OL-KR24 76 78


Local_5 Zone intersection, mOL-KR11 212.1 217.1OL-KR46 132.2 136.2

Hydraulic connection between a zone and a drillhole

This kind of hydraulic connections occur e.g. above and below the HZ20 system, when the system is modelled with the main drillhole intersections taking measured transmissivities and interpreted pressure responses into account. The geometry cannot

170

OL-KR03 & OL-KR39

TR3804TR3898

TR3927TR3977

TR3985

INJ3927INJ3927

INJ3985

405939523922387738253776

-6

-5

-4

-3

-2

-1

0

1

2

3

4

5

15.8.09 29.8.09 12.9.09 26.9.09 10.10.09 24.10.09 7.11.09 21.11.09 5.12.09 19.12.09 2.1.10

Date

Hea

d, m

.a.s

.l.

0

220

KR03 L1 469.2-473.2 KR03 L2 399.2-468.2 KR03 L3 380.8-398.2 KR03 L4 339.2-343.2 KR03 L5 242.6-253.2 KR39 L1 470-503KR39 L2 400-409 KR39 L3 375-384 LEAK ONKALO chainage

be interpreted for these connections. The drillhole intersections are shown in Appendix 1, the labels refer to the zone.

Hydraulic connection between ONKALO and drillholes

Chainage 3804 m A hydraulic feature interpreted as a local-scale zone was intersected by the access tunnel in autumn 2009 (Vaittinen et al. 2010a). A hydraulic connection to packed-off drillholes OL-KR3 and -KR39 was observed when the head in packed-off sections OL-KR3 L4 and -KR39 L3 started to decrease on 1.9.2009 (Figure 6-3). A leakage occurred through probe hole A at chainage 3 804 m (Figure 6-4). The leakage was located at the probe hole depth at 27 m. By the end of 2009, groundwater level in packed-off sections OL-KR39 L1-L3 was below the measurable depth and head in packed-off sections OL-KR3 L1-L5 decreased continuously.

Because drawdown occurs in several monitoring sections in both drillholes (cf. Figure 6-4), a combination of sub-horizontal and sub-vertical hydrogeological features is most probable. The drillhole intersections are shown in Appendix 1, the labels refer to the chainage.

Figure 6-3. Head diagrams of the packed-off sections responding to leakage at chainage 3 804 m in the ONKALO access tunnel.

171

L1

L2L3

L1

L5

L4

L3

L2

L1

L2L3

L1

L5

L4

L3

L2

Figure 6-4. At first, leakage occurred along probe hole PR3804A. The packed-off sections showing a response in drillholes OL-KR3 and -KR39 are labelled.

6.2 Single fracture transmissivities

The locations of the 10 single fractures with anomalous transmissivity are shown in Figure 6-5; half of them are located in drillholes OL-KR49 – -KR53 drilled after the 2008 model. Eight of the transmissivities are located above -150 m and two of them, observed in drillhole OL-KR49, are close to the planned repository depth between -400 and -500 m (cf. Table 6-7).

Table 6-7. Anomalous fracture transmissivities according to the classification presented in Chapter 2.4.1.

Drillhole Depth, m T, m2/s Depth, m.a.s.l.OL-KR06 99.26 5.75E-06 -74.31OL-KR33 98.51 2.54E-06 -73.43OL-KR33 117.09 8.16E-06 -87.87OL-KR41 69.4 2.21E-06 -60.79OL-KR41 83.6 2.71E-06 -73.99OL-KR49 86.1 6.20E-06 -66.12OL-KR49 533.6 4.37E-07 -416.66OL-KR49 620.7 5.59E-07 -482.14OL-KR50 78.8 2.40E-06 -71.83OL-KR53 175.9 2.98E-06 -129.69

172

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

T, m ²/s>1E -8>1E -7>1E -6>1E -5

Figure 6-5. The location of single fractures with anomalous transmissivity, view towards southeast. Unoriented fractures are shown as horizontal squares.

173

7 PARAMETERISATION OF INITIAL HYDRAULIC PROPERTIES FOR NUMERICAL FLOW MODELLING

7.1 Transmissivity of zones

The summary statistics of the transmissivities of the deterministic zones described in Chapter 5 are presented in Table 7-1. The measured maximum values are given to allow possible calibration or an uncertainty analysis in numerical flow modelling.

An alternative proposal for transmissivity was based on the general depth dependency of drillhole specific values as shown in Figure 7-1. In addition, the zones were classified into different transmissivity classes based on the means of the zone specific transmissivities and their mean depths (cf. Table 7-1 and Figure 7-2). Two different options are proposed for lineaments due to their unknown hydraulic character (no measured value in any hole).

Table 7-1. Basic statistics of the determined drillhole specific transmissivities of deterministic zones.

model 2010 Note

Bound_Lin-5.5 ***) 1 -5.5 ***) will be updated when geological

interpretation readyHZ001 -5.7 0.8 6 -5.1 0.5 0.4HZ008 -5.5 0.7 2 -5 0.8 0.6HZ19A -5.0 0.8 26 -3.8 0.3 0.2HZ19B -5.4 0.7 15 -3.9 0.3 0.2HZ19C -5.3 0.9 30 -4 0.3 0.2HZ20A -5.3 0.9 20 -4.3 0.3 0.2HZ20B -5.6 0.6 15 -4.8 0.3 0.2HZ21 -7.9 1.3 13 -6.1 0.6 0.4

HZ21B -6.3 0.8 8 -5.1 0.5 0.3HZ039 -5.2 1 -5.2

HZ099 -6.6

0.8 9 -6 0.4 0.3

probably depth dependentBFZ100 -7.6 *) 2.2 10 -6.5 1.1 0.8 *)include uncertain values - depth

dependency will be useddepth dependent between 0-200m

0 m=-6.5-200 m=-9

<-200 m =-9HZ146 -5.7 **) 1 8 -4.2 0.6 0.4 **) -depth dependency will be used

depth dependent between 0-500m0 m=-4.5

-500 m=-7<-200 m =-7

Confidence limit of the

mean (75 %)

Confidence limit of the

mean (90 %)

Max T (log)

Zone name Transmissivity Geometric mean

(log, m2/s)

Standard deviation

Log(T)

Number of borehole

intersections

174

y = 0.003705x - 4.829150

-10

-9

-8

-7

-6

-5

-4

-3-1000-900-800-700-600-500-400-300-200-1000

Elevation (m.a.s.l.)

log

T (m

2 /s)

log TLinear (log T)

Table 7-2. Depth dependent transmissivity of classified zones.

Class A Class B Class C Class D Class E

depth log T T (m2/s)

log T T (m2/s) log T

T (m2/s)

log T T (m2/s)

log T T (m2/s)

0 -4.3 5E-05 -4.83 1.5E-05 -5.3 5E-06 -7.7 2E-08 -8.3 5.0E-09 -450 -10 1.0E-10 -600 -10 1E-10 -1000 -8 1E-08 -8.53 3E-09 -9 1E-09 -2000 -8 1E-08 -8.53 3E-09 -9 1E-09 -10 1E-10 -10 1.0E-10 Class A: HZ20A, HZ20B, HZ39, HZ21B Class B: HZ001, HZ008, HZ19A, HZ19C, HZ146, BFZ152, Lineaments (option1) Class C: HZ19B, HZ099, HZ21 Class D: BFZ175, BFZ159, BFZ160, BFZ161, site-scale BFZs without drillhole intersections, Lineaments (option2) Class E: BFZ100

Figure 7-1. General depth dependency of measured transmissivities.

175

HZ21B

HZ21

HZ20B

HZ20A

HZ19C

HZ19B

HZ19A

HZ146

HZ099

HZ039

HZ008

HZ001

BFZ100

-1000

-900

-800

-700

-600

-500

-400

-300

-200

-100

0-11 -10 -9 -8 -7 -6 -5 -4 -3

log T (m2/s)

Elev

atio

n (m

.a.s

.l.)

HZ001BFZ100HZ008HZ039HZ099HZ146HZ19AHZ19BHZ19CHZ20AHZ20BHZ21HZ21Bmean of zoneBFZ meansBFZ152BFZ175BFZ othersclass Aclass Bclass Cclass Dclass E

Figure 7-2. Measured drillhole specific transmissivities, the means of zone transmissivities with mean depths, and the depth dependent transmissivity of classified zones (cf. Table 7-1).

7.2 Hydraulic conductivity of bedrock outside deterministic zones

The alternative approach to determine the hydraulic conductivity of bedrock outside the deterministic zones, introduced in 2008 (Vaittinen et al. 2009b), is used in the 2010 model. The applied data were updated according to the new determination of transmissivity depth ranges for the zones, and new drillhole data.

Following the approach, bedrock outside the deterministic zones was divided into 50 m thick depth sections. The average hydraulic conductivity Keff was calculated for each drillhole (i.e drillhole-specific Keff) based on the sum of fracture-specific transmissivities divided by drillhole length within the depth section in question.

For the estimation of the model parameters, the averages of the logarithms of the aforementioned drillhole-specific Keff-values in different depth sections were calculated based on two different approaches:

176

0

10

20

30

40

50

60

70

80

90

100

-12 -11 -10 -9 -8 -7 -6 -5 -4log K (m/s)

Cum

ulat

ive

perc

ent

0-50m50-100m100-150m150-200m200-250m250-300m300-350m350-400m400-450450-500m500-550m550-600m600-650m650-700m-700...-750

� If no transmissive fracture was observed within a drillhole section with the PFL-tool, the hydraulic conductivity was assumed to be 1·10-11 m/s.

� Cumulative plots of the calculated hydraulic conductivities were used for the determination of average K-values.

The cumulative plots of hydraulic conductivities in the 50 m depth sections together with fitted normal distributions down to the depth class of -550 – -600 m are shown in Figure 7-3. The averages of both the methods are presented in Figure 7-4. As a result, a partly depth dependent initial value for hydraulic conductivity is proposed for numerical flow modelling purposes and is shown in Figure 7-4 and in Table 7-3. Corresponding values for the 2008 model are also shown in Figure 7-4. Differences between the 2008 and 2010 models are minor at shallow depths down to -250 m, but deeper a clear decrease in hydraulic conductivity can be seen for most of the 50 m depth sections. The difference is caused by the new method in which fairly high transmissivities near the zones are included in zone transmissivity in the transmissivity depth range determinations as described in Chapter 2.4.2.

Figure 7-3. Cumulative plots of hydraulic conductivities in 50 m depth sections together with fitted normal distributions down to a depth section of -550 – -600 m.

177

0

100

200

300

400

500

600

700

800

900

1000

-12 -11 -10 -9 -8 -7 -6 -5log K (m/s)

Dep

th, m

.b.s

.l.

average all w-11 2008ave all w-11 2010geom ave of cum plot 2008geom ave of cum plot 2010model 2008model 2010

Figure 7-4. Calculated hydraulic conductivities for 50 m depth sections using the averages of 1·10-11 (average all w-11) for drillhole sections where no transmissive fracture was found with the PFL-tool, or averages based on cumulative distributions (geom ave of cum plot). In addition, the proposed lines for hydraulic conductivity for the numerical flow model are shown (dotted black lines). Corresponding values for the 2008 2008 are also shown.

Table 7-3. Proposed hydraulic conductivity of the rock for numerical flow modelling.

Depth range, m K, m/s Note 0 – -200 3·10-7 – 1.5·10-10 Linear depth dependency between 0 – -200 m

-200 – -500 1.5·10-10 – 1.5·10-11 Linear depth dependency between -200 – -500 m -500 – 1.5·10-11

178

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25 30 35 40Thickness (m)

Cum

ulat

ive

perc

ent

BFZ100HZ001HZ099HZ146HZ19AHZ19BHZ19CHZ20AHZ20BHZ21HZ21BHZ039

7.3 Thickness of zones

To provide more realistic parameters for numerical flow modelling purposes, the determination of the thickness of the zones is based on observed transmissive fractures within the transmissivity depth ranges (cf. Chapters 2.4.2 and 5). The drillhole-specific intersection lengths were determined based on the transmissive fractures measured with the PFL-tool. The intersection lengths were corrected to the real thicknesses by the angle between the drillhole and the zone orientation. The corrected drillhole specific thicknesses are shown in Figure 7-5. If only one transmissive fracture was found, the thickness was set to 0.1 m. The medians of the corrected thicknesses are shown for all zones in Table 7-4. Corrected thicknesses based on zone intersections (cf. Chapters 2.4.2 and 5) were also determined and the medians are given in Table 7-4. As can be seen in Figure 7-5, variation of drillhole specific thicknesses is high within the zones. Simplification for the needs of numerical flow simulations was based on the data shown in Figure 7-5 and Table 7-4 and the proposed thicknesses are shown in Table 7-4. The thicknesses were classified by expert judgement into three depth classes (2 m, 4 m, and 8 m). The final decision was mostly based on the medians shown in Figure 7-5. The geological character of the zones was also used in the determination.

Figure 7-5. Cumulative plots of the corrected thicknesses of the zones based on transmissivities found with PFL within the transmissivity depth range (cf. Chapter 2.4.2).

179

Table 7-4. The medians of drillhole specific thicknesses based on zone intersections and transmissive fractures found within transmissive depth ranges, and the proposed simplified thicknesses for numerical flow simulations are listed.

Zone Median of corrected drillhole specific

thickness based on model (m)

Median of corrected drillhole specific

thickness based on transmissivity (m)

Proposed thickness for the numerical flow simulations

(m)

BFZ100 2.2 0.1 2 HZ001 2.0 0.1 2 HZ008 19.2 10.0 8 HZ039 3.5 1.0 4 HZ099 5.1 8.0 8 HZ146 4.4 0.6 4 HZ19A 3.5 3.8 4 HZ19B 2.0 3.5 4 HZ19C 2.2 2.1 2 HZ20A 2.3 8.4 8 HZ20B 4.1 8.4 8 HZ21 8.9 0.1 8

HZ21B 7.6 8.0 8 Bound_Lin *) 1.3 0.8 2

*) uncertain - preliminary data from drillhole OL-KR53 was used

7.4 Fracture space and aperture

For the calculation of the flow velocity in numerical flow simulations, the averages (arithmetic means) of hydraulic apertures (void space) and fracture spaces were calculated based on transmissive fractures found by flow logging. The maximum values of fracture specific transmissivities and an empiric factor C=10 between the ideal parallel plate hydraulic aperture (cubic law) and the void space of the actual flow were used as recommended in Taivassalo & Saarenheimo (1991). The determined averages of the fracture space (fs) and the aperture (a) can be easily converted to flow porosity by the equation a/fs.

The mean and median fracture spaces and the mean apertures for the deterministic zones as well as the calculated flow porosities are shown in Table 7-5. Flow porosities are shown for mean and median fracture spaces. Porosities based on median fracture spaces are probably better due to the probable log-normal distribution of the fracture space (the mean is sensitive to a few very long fracture spaces) and also due to the effect of the limit of the tool (PFL) on detecting less transmissive fractures which would strongly decrease the averages of fracture spaces. Because data for zone HZ008 are limited, the same values as for zone HZ20B are proposed to be used due to the similar character of the zones. The values for bounding lineaments are also uncertain because preliminary data from OL-KR53 were used. The zone intersection was later removed and no actual data exist on bounding lineaments. In the transmissivity section, bounding lineaments are classified to resemble either zones HZ001, HZ008, HZ19A and HZ19C or significantly less transmissive brittle deformation zones. The determinations of aperture and flow porosity for lineaments are therefore highly uncertain.

180

Corresponding values for bedrock between and outside the deterministic zones divided into six depth classes are shown in Table 7-6.

Table 7-5. Mean apertures (mm) and fracture spaces (m) of transmissive fractures found by flow logging for deterministic zones. In addition, the mean flow porosities calculated by aperture/fracture space are shown.

Zone Mean aperture mm (C=10)

Mean fr space,

m

Median fr space,

m

Flow porosity (mean fr space)

Flow porosity

(median fr space)

BFZ100 0.7 1.174 1.005 5.6E-04 6.6E-04 Bound Lin *) 1.0 0.650 0.650 1.5E-03 1.5E-03

HZ001 1.5 5.805 5.805 2.6E-04 2.6E-04 HZ039 1.4 1.300 1.300 1.1E-03 1.1E-03 HZ099 0.4 2.865 1.330 1.5E-04 3.3E-04 HZ146 0.8 1.820 0.930 4.3E-04 8.5E-04 HZ19A 1.3 1.381 1.005 9.5E-04 1.3E-03 HZ19B 1.4 2.109 1.485 6.7E-04 9.5E-04 HZ19C 1.1 1.762 1.175 6.3E-04 9.4E-04 HZ20A 0.9 2.619 1.855 3.4E-04 4.8E-04 HZ20B

(+HZ008) 0.8 2.982 2.045 2.8E-04 4.1E-04

HZ21 0.3 3.620 2.780 9.2E-05 1.2E-04 HZ21B 0.5 3.961 3.220 1.2E-04 1.5E-04

*) uncertain - preliminary data from OL-KR53 was used

Table 7-6. Mean apertures (mm) and fracture spaces (m) of transmissive fractures found by flow logging for bedrock between and outside deterministic zones. In addition, mean flow porosities calculated by aperture/fracture space are shown.

Depth range, m

Mean aperture mm (C=10)

Mean fr space,

m

Median fr space,

m

Flow porosity (mean fr space)

Flow porosity

(median fr space)

0 – -50 0.57 1.8 1.2 3.2E-04 4.9E-04 -50 – -100 0.35 3.4 1.6 1.0E-04 2.1E-04 -100 – -200 0.27 8.2 2.8 3.3E-05 9.6E-05 -200 – -300 0.24 24.4 8.3 9.7E-06 2.8E-05 -300 – -500 0.25 30.0 12.7 8.3E-06 2.0E-05

-500 – 0.30 63.5 44.5 4.7E-06 6.6E-06

181

8 UNCERTAINTY ASSESSMENT

The uncertainties of the hydrogeological structure model are related to the conceptual understanding of the site, the observation of hydrogeological parameters, the interpretation of the observations, and hydraulic features not linked to the site scale structure model.

8.1.1 Conceptualisation of rock mass

The ductile deformation model is applied to provide the geological background for the hydrogeological conceptualisation of the rock mass. The ductile deformation model contains interpretation of tectonic units and sub-units on Olkiluoto Island. According to the hypothesis, hydraulic connections seem to occur within each of the main units and connections between units are weak. Both geological character and geophysical and hydrological connections support the existence of tectonic units and sub-units. However, hydrological observation is mostly focused on CTU and therefore cross-hole measurements reaching more than one tectonic unit are needed to confirm the hypothesis.

8.1.2 Observation of hydrogeological parameters

The observation of the groundwater table and head is described in detail in Olkiluoto Monitoring Reports (e.g. Vaittinen et al. 2010a). Because the modelling of the hydrogeological zones is mainly based on the interpretation of head observations, the frequency of observation and whether open or packed-off drillholes are monitored are of major importance. Field activities that affect the head typically last a few days, but open drillholes are monitored only once a week. Head changes in open drillholes may therefore not be recorded. When drillholes are packed-off, not every transmissive fracture can be taken into account, and on the other hand, more than one zone may be located within one packed-off section.

8.1.3 Interpretation of observations

The continuity of the hydrogeological zones is primarily based on the interpretation of pressure and flow responses observed between drillholes. Many uncertainties are related to the interpretation of pressure responses. Hydraulic transmissivity along a drillhole affects both the observations and the impacts caused by field activities in a drillhole. In an open drillhole, head changes within a hydrogeological zone with low head or low transmissivity may be masked by other zones with higher head or transmissivity. If open drillholes occur, hydraulic connections cannot be interpreted unambiguously, because pressure effects are spread along the open drillholes to more than one hydrogeological zone at the same time. Since the 2008 model, the uncertainty related to the effect of open drillholes is notably lower due to the increased number of packed-off drillholes. A more detailed description of the uncertainties is given in Vaittinen et al. (2008b).

An analysis of the detected flow responses is under development. The use of the method is therefore still in progress and may contain uncertainties, which have not yet been quantified. In principle, changes detected in flow caused by different disturbances have been assessed to be valuable but have to some extent been restricted due to the unknown

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or not precisely determined source of disturbance. A typical disturbance is pumping of an open drillhole, which may intersect several potential zones or fractures that are in hydraulic connection with a drillhole measured with PFL. The determination of flow changes, if any, may also be uncertain due to the effect of the changed general groundwater conditions between test results obtained at different times.

8.1.4 Geometry of the zones

The main objective of the hydrogeological structure model is to be used as the geometry in site scale numerical groundwater flow modelling in such a way that the changes required for numerical purposes are as minor as possible sustaining consistency between the models. Hydraulic connectivity is required within the numerical model, i.e. between the zones and the boundaries of the model. Because the main zones are all sub-horizontal and ground surface intersections are not known, the required hydraulic connections form the most uncertain part of the model. The sub-horizontal extent of the hydrogeological zones outside the area covered by the deep drillholes is based on expert judgement and is therefore obviously uncertain.

8.1.5 Other hydraulic features

As part of the uncertainty assessment, hydraulic connections and single fractures with anomalous transmissivity not linked with the site scale hydrogeological zones are reported (Chapter 6). The character of anomalous single fractures cannot be assessed.

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9 SUMMARY AND DISCUSSION

9.1 Summary

The hydrogeological structure model of the Olkiluoto site describes the hydraulically significant zones on site scale. The model provides deterministic geometries and hydrogeological properties related to groundwater flow for the zones and the bedrock, for use in the numerical modelling of groundwater flow and geochemical transport and thereby in the safety assessment.

Background

The first hydrogeological structure model for numerical groundwater flow simulations was compiled in 1992 and the model has since been updated approximately every two years as new investigation data have been gathered. The modelling approach has been changed over the years. A major change was dividing the modelling of the bedrock in 2003 into four separate disciplines: geological model, rock mechanical model, hydrogeological model, and hydrogeochemical model.

The following issues have been taken into account as the hydrogeological structure model has been updated since 2003: 1) high fracture transmissivities enabling groundwater flow, 2) anomalous low heads indicating connection to a discharge area, 3) requirements related to numerical groundwater flow simulations, i.e. hydraulic connectivity, and 4) extensive brittle deformation zones or anomalous geophysical features close to the planned repository facilities indicating possible groundwater flow routes.

The previous hydrogeological model was compiled in 2008 and this updated version is based on data available at the end of May 2010. New investigation data have been gathered both on ground surface and underground: five new deep drillholes have been drilled since the previous hydrogeological model update in 2008, the excavation of the ONKALO access tunnel has continued to a length of 4 300 m, and the raise boring of a personnel shaft and two ventilation shafts has reached the depth of -290 m. The hydrogeological structure model covers the volume enclosed by the bounding lineaments surrounding Olkiluoto Island and a depth range down to -2 000 m. The area with deep drillholes covers approximately half of the whole area and a depth range down to -1 000 m.

Modelling

The applied concept of the hydraulic character of crystalline bedrock is to assess the rock mass as strongly channelled and with the majority of the groundwater flows along hydrogeologically essential deformation zones. The ductile deformation model (Aaltonen et al. 2010) is applied to provide the geological background for the hydrogeological conceptualisation of the rock mass

The compilation of the hydrogeological structure model is based on analyses of fracture transmissivities, head distribution, pressure and flow responses, and site scale geological brittle deformation zones. The analysis of head observations focuses on

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cross-hole observations to determine the continuity and the extent of the zones. Cross-hole observations contain the results of earlier interference tests as well as flow and pressure responses caused by various field activities.

A consideration of the hydrogeological model against the brittle deformation model (Aaltonen et al. 2010) shows that the site scale brittle deformation zones, whose continuity between the drillholes is based on geophysical measurements, coincide with the hydrological cross-hole connections. However, high fracture transmissivities cover the deformation zones only partly indicating that high transmissivities may have focused on a certain part of the brittle deformation zones.

Geometry of the zones

According to the geological model, the faults are planar/semiplanar features (Aaltonen et al. 2010). In this update, the occurrence of transmissive fractures is the only parameter that defines the existence of a hydrogeological zone in a drillhole, except for intensively fractured zone HZ21 located below the planned repository level. Zone HZ21 has originally been modelled on the basis of engineering geology, hydrological connections, geophysics, and a fitting geometry and the updating is based on the same parameters. As in the previous version of the hydrogeological model, no limit value is applied to fracture transmissivity to determine the occurrence of a zone.

The main issue when determining the length of a zone intersection in a drillhole is that all substantial transmissive fractures are included in the zone. In most cases there are only one or two highly transmissive fractures dominating the groundwater flow. The location of a zone is defined by these fractures. Because it is difficult to determine rules for the length of zone intersections based only on the occurrence of transmissive fractures, the drillhole structure criteria defined in the 2003/1 bedrock model version (Vaittinen et al. 2003) are applied. The intersection length is primarily determined according to fracture frequency and secondarily according to the location of a transmissive fracture. In addition, the transmissivity depth range has been introduced and determined for each drillhole intersection to describe the hydrogeological influence zone around a zone. The length of a transmissivity range is applied to define the proportion of sparsely fractured rock for DFN modelling and in some cases to model LDFs.

The upper and lower surfaces of the zones follow the defined drillhole intersections. In the area with deep drillholes, the surrounding drillholes control the extent of the zones. The extrapolation of the zones outside the area is based on expert judgement and extrapolated corner coordinates are calculated applying the nearby drillhole intersections. Linked lineaments (Korhonen et al. 2005) are used to define the shape of the zones to visually follow the dominant trends of the geological features.

Most of the zones are assessed to have a limited extension and extrapolation therefore covers relatively small areas. The reasons for the strongly restricted modelling of the zones include 1) higher than expected drawdowns based on the infinite radial flow field along the confined aquifer during the pumping tests, 2) conceptual tectonic units and observed differences in hydrogeological properties, e.g. total transmissivities of the drillholes and pressure responses between the drillholes, and 3) the results of numerical

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flow modelling with extended zones in the 2006 version (Andersson et al. 2007). If there are no indications of the size of the zones being restricted, the zones are extended to intersect the bounding lineaments.

Transmissivity of the zones and hydraulic conductivity of the bedrock

The sum of fracture specific transmissivities measured mainly with the PFL-tool was used for each drillhole intersection of the zones. The results of the pumping tests were also used for very highly transmissive drillhole sections due to the uncertainties related to the determination of the high flow rate of the PFL-tool. A geometric mean transmissivity has been assigned to the zones. Transmissivities outside the determined transmissivity depth ranges of the zones were used for an analysis of the hydraulic conductivity of the bedrock. The assessment of hydraulic conductivity is a very complicated task especially deep in the bedrock due to the great amount of drillhole sections below the measurement limit of the PFL-tool. The effect of the drillhole sections below the measurement limit was assessed in the current Report by compiling cumulative plots for 50 m long drillhole sections taking also these “non-conductive” sections into account and fitting lognormal distributions (curves) to such data and using the geometric means of these curves to estimate the mean hydraulic conductivity of the bedrock.

Uncertainty assessment

The uncertainties of the hydrogeological structure model are related to the conceptual understanding of the site, the observation of hydrogeological parameters, the interpretation of the observations, and hydraulic features not linked to the site scale structure model. The main uncertainty in the conceptual understanding of the site is related to tectonic units and their effects on the horizontal extent of the zones. Uncertainty in the observation of groundwater table and head is mostly caused by the varying frequency of observation depending on whether open or packed-off drillholes are monitored. Many uncertainties are related to the interpretation of observations. The most common uncertainties are caused by disturbing hydraulic effects along open drillholes. As part of the uncertainty assessment, hydraulic connections not linked with the site scale hydrogeological zones are discussed. Most of the connections are assessed to be local features.

Results

As a result of the modelling campaign, hydrogeological zones HZ001, HZ008, HZ19A, HZ19B, HZ19C, HZ20A, HZ20B, HZ21, HZ21B, HZ039, HZ099, OL-BFZ100, and HZ146 were included in the structure model. An alternative interpretation of the geometry has been introduced for the HZ19 system. Compared with the previous model, zones HZ039 and OL-BFZ100 have been added to the compilation, zone HZ004 has been replaced by zone HZ146, and zone HZ21B has been moved to the basic model.

The hydrogeological properties of the zones and bedrock were parameterised for numerical flow simulation purposes. The depth dependent geometric means of the measured transmissivities were proposed for use for the zones, and the hydraulic

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conductivity of the bedrock as a function of depth was assessed. In addition, values for thickness, fracture space, and aperture were suggested for the zones.

9.2 Discussion

Concerning site-scale modelling, discussion on the extent of the hydrogeological zones has continued during the current modelling process. Many uncertainties are related to the interpretation of the extents and dimensions of the HZs. The reasoning for the restricted modelling of the zones has been based on 1) higher than expected drawdowns based on the infinite radial flow field along the confined aquifer during pumping tests, 2) the effect of tectonic units and sub-units, and 3) the results of numerical flow modelling with the extended zones of the 2006 version (Andersson et al. 2007).

The hydrogeological conceptualisation of the rock mass is based on the interpretation of tectonic units and sub-units on Olkiluoto Island. Since the previous modelling campaign, confidence in the concept of the tectonic model has increased notably, as new investigation data within the eastern area have been utilised for GSM 2.0. Based on geological and geophysical data, the orientation of the Liikla Shear Zone changed from sub-vertical to moderately dipping, and therefore the restrictive effect on the HZs towards south and southeast changed, as well. In 2008, both the HZ19 and the HZ20 zone were horizontally restricted by LSZ, moderately dipping LSZ enables a more extensive size below the zone. Currently the extrapolated extents of the zones outside the drillhole intersections are based on geophysical data and expert judgement.

The drillholes located in the eastern area should be packed-off to establish baseline conditions and to enable the interpretation of major hydrogeological zones by means of pumping tests. The coincidence of the hydrogeological features and the geophysical cross-hole and seismic reflection survey provide valuable information on potential hydraulic continuity, although hydraulic connections typically cover a smaller area than geophysical continuities in Olkiluoto.

The construction of the repository is proceeding from the ONKALO to the first disposal panel and hydrogeological structure modelling from site-scale to panel-scale modelling. The packing-off of the drillholes within NTU enables pumping tests to study hydraulic connections especially related to the HZ099 and HZ21 zones. Information on hydraulic connectivity is needed in the characterisation of the most probable discharge routes close to the first panel area to the sea.

So far, the hydraulic monitoring of hydraulic head has focused on the main flow paths enabling the studying of site-scale hydrogeological features. More detailed information is needed for panel-scale modelling. The leakage within CTU into the ONKALO since penetration through the HZ20 system has revealed weak hydraulic connections to the modelled zones providing valuable information on the hydraulic character of the system. In addition, weak hydraulic connections within sparsely fractured rock have been observed through hydraulic pressure and flow responses, although the features cannot be determined geologically. Examples of this kind of connections are zone HZ056 and the connection between ONKALO and drillholes OL-KR3 and -KR39.

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The same kind of data should be gathered from the all hydrogeological features close to the first panel to characterise the hydraulically connected fracture network. Useful information on panel-scale characterisation and modelling would be obtained by integration of ONKALO data and drillhole data taking also geophysical data into account.

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REFERENCES

Aalto, P. (ed.), Kosunen, P., Lahti, M., Pere, T., Tarvainen, A-M., Toropainen, V., Pekkanen, J. & Pöllänen, J. 2011. Drilling and associated drillhole measurements of the pilot hole ONK-PH13. Eurajoki, Finland: Posiva Oy. Working Report 2011-28.

Aaltonen, I. (ed.), Lahti, M., Engström, J., Mattila, J., Paananen, M., Paulamäki, S., Gehör, S., Kärki, A., Ahokas, T., Torvela, T. & Front, K. 2010. Geological Model of the Olkiluoto Site, Version 2. Eurajoki, Finland: Posiva Oy. Working Report 2010-70. 580 p.

Ahokas, H. 2011. Analysis on the quality of transmissivities measured by different methods. Eurajoki, Finland: Posiva Oy. Working Report (in prep.).

Ahokas, H., Hellä, P., Ahokas, T., Hansen, J., Koskinen, K., Lehtinen, A., Koskinen, L., Löfman, J., Mészáros, F., Partamies, S., Pitkänen, P., Sievänen, U., Marcos, N., Snellman, M. & Vieno, T. 2006. Control of water inflow and use of cement in ONKALO after penetration of fracture zone R19. Eurajoki, Finland: Posiva Oy. Working Report 2006-45. 160 p.

Ahokas, H. & Herva, S. 1993. Summary of hydrological observations in Olkiluoto area, Eurajoki (in Finnish with an English abstract). Helsinki, Finland: Teollisuuden Voima Oy. 27 p. + App. TVO/Site investigations Work Report 92-35.

Ahokas, H. and Pöllänen, J. 2011. Evaluation of Transmissivity Data from the Olkiluoto Site – Drillholes OL-KR1 – OL-KR53. Eurajoki, Finland: Posiva Oy. Working Report (in prep.).

Ahokas, H., Vaittinen, T., Tammisto, E. & Nummela, J. 2007. Modelling of hydro zones for the layout planning and numerical flow model in 2006. Eurajoki, Finland: Posiva Oy. Working Report 2007-01. 212 p.

Ahokas H., Tammisto, E. & Lehtimäki, T. 2008. Baseline head at Olkiluoto. Eurajoki, Finland: Posiva Oy. Working Report 2008-69. 191 p.

Ahokas, H. & Äikäs, K. 1991. Geology and hydrology of the Cape Ulkopää at Olkiluoto (in Finnish with an English abstract). Helsinki, Finland: Nuclear Waste Commission of Finnish Power Companies. Report YJT-91-05. 95 p.

Ahokas, T. 2010. Preliminary modelling of the 2010 MAM survey data. Eurajoki, Finland: Posiva Oy. Working Report 2010-75. 72 p.

Ahokas, T. & Paananen, M. 2010. Updated and integrated modelling of the 1995 – 2008 Mise-à-la-masse survey data in Olkiluoto. Eurajoki, Finland: Posiva Oy. Working Report 2010-08. 265 p.

Andersson, J.-E., Ekman, L., Nordqvist, R. & Winberg, A. 1991. Hydraulic testing and modelling of a low-angle fracture zone at Finnsjön. Tectonophysics 336, pp. 45-77.

190

Andersson, J., Ahokas, H., Hudson, J.A., Koskinen, L., Luukkonen, A., Löfman, J., Keto, V., Pitkänen, P., Mattila, J., Ikonen, A.T.K. & Ylä-Mella, M. 2007. Olkiluoto site description 2006. Eurajoki, Finland: Posiva Oy. Posiva 2007-03. ISBN 978-951-652-151-3. 536 p.

Anttila, P., Ahokas, H., Front, K., Hinkkanen, H., Johansson, E., Paulamäki, S., Riekkola, R., Saari, J., Saksa, P., Snellman, M., Wikström, L. & Öhberg, A. 1999. Final disposal of spent nuclear fuel in Finnish bedrock – Olkiluoto site report. Helsinki, Finland: Posiva Oy. Posiva 99-10. ISBN 951-652-065-0. 206 p.

Buoro, A., Dahlbo, K., Wiren, L., Holmén, J., Hermanson, J. & Fox, A. (ed.) 2009. Geological discrete-fracture network model (version 1) for the Olkiluoto site, Finland. Eurajoki, Finland: Posiva Oy. Working Report 2009-77. 157 p.

Caine, J.S., Evans, J.P. & Forster, C.B. 1996. Fault zone architecture and permeability structure. Geology 24, pp. 1025-1028.

Cosma, C., Cozma, M., Juhlin, C. & Enescu, N. 2008. 3D seismic investigations at Olkiluoto 2007 factual report. Eurajoki, Finland: Posiva Oy. Working Report 2008-43. 49 p.

Cosma, C., Enescu, N., Adam, E. & Balu, L. 2003. Vertical and horizontal seismic profiling investigations at Olkiluoto, 2001. Eurajoki, Finland: Posiva Oy. Posiva 2003-01. ISBN 951-652-115-0. 115 p.

Enescu, N., Cosma, C. & Balu, L. 2003. Seismic VSP and crosshole investigations in Olkiluoto, 2002. Eurajoki, Finland: Posiva Oy. Working Report 2003-13. 131 p.

Enescu, N., Cosma, C., Balu, L., Heikkinen, E., Vaittinen, T., Saksa, P., Palmén, J. & Nummela, J. 2004. Reflection seismics using boreholes at Olkiluoto in 2003 – from investigation design to result validation, Volumes I & II. Eurajoki, Finland: Posiva Oy. Working Report 2004-62. 167 p.

Gudmundsson, A. 2001. Fluid overpressure and flow in fault zones: field measurements and models. Tectonophysics 336, pp. 183-197.

Hakkarainen, V. 1984. Geological survey of Olkiluoto and its surroundings (in Finnish). Nuclear Waste Disposal Research, Work Report G-3.1-1. Geological Survey of Finland, Espoo. 19 p.

Hartley, L., Appleyard. P., Baxter, S., Hoek, J., Roberts, D., Swan, D. & Follin, S. 2011. Development of hydrogeological discrete fracture network model for the Olkiluoto site descriptive model 2010. Eurajoki, Finland: Posiva Oy. Working Report (in prep.).

Hartley, L., Hoek, J., Swan, D., Roberts, D., Joyce, S. & Follin, S. 2009. Development of a Hydrogeological Discrete Fracture Network Model for the Olkiluoto Site Descriptive Model 2008. Eurajoki, Finland: Posiva Oy. Working Report 2009-61. 226 p.

191

Hellä, P., Ahokas, H., Palmén, J. & Tammisto, E. 2006. Analysis of Geohydrological Data for Design of KBS-3H Repository Layout. Eurajoki, Finland: Posiva Oy. Working Report 2006-16. 34 p.

Hellä, P. (ed.), Ikonen, A., Mattila, J., Torvela, T. & Wikström, L. 2009. RSC-Programme - Interim Report. Approach and Basis for RSC Development, Layout Determining Features and Preliminary Criteria for Tunnel and Deposition Hole Scale. Eurajoki, Finland: Posiva Oy. Working Report 2009-29. 118 p.

Hirvonen, H., Hatanpää, E. & Ahokas, H. 2007. Groundwater sampling at Olkiluoto, Eurajoki from the borehole OL-KR6 during a long-term pumping test in 2006. Eurajoki, Finland: Posiva Oy. Working Report 2007-19. 83 p.

Hämäläinen, H. 2009. Hydraulic Conductivity Measurements with HTU at Eurajoki, Olkiluoto, Drillholes OL-KR40, OL-KR42 and OL-KR45 in 2008. Eurajoki, Finland: Posiva Oy. Working Report 2009-104. 82 p.

Juhlin, C. & Cosma C. 2007. A 3D surface seismic pilot study at Olkiluoto, Finland: Acquisition and processing report. Eurajoki, Finland: Posiva Oy. Working Report 2007-65. 47 p.

Jääskeläinen, P. 1998. Pumping tests in boreholes KR1 and KR4 at Olkiluoto in spring 1998 (in Finnish with an English abstract). Helsinki, Finland: Posiva Oy. Working Report 98-76. 51 p.

Karttunen, P. ed., Kemppainen, K., Kosunen, P., Lampinen, H., Pöllänen, J., Rautio,T., Tarvainen, A-M. & Lamminmäki, T. 2009. Drilling and the Associated Drillhole Measurements of the Pilot Hole ONK-PH8. Eurajoki, Finland: Posiva Oy. Working Report 2009-16. 134 p.

Karttunen, P. ed., Kosunen, P., Lamminmäki, T., Pekkanen, J., Pöllänen, J., Tarvainen, A-M. & Toropainen, V. 2010. Drilling and the Associated Drillhole Measurements of the Pilot Hole ONK-PH9. Eurajoki, Finland: Posiva Oy. Working Report 2010-9. 194 p.

Karttunen, P. Mancini, P. (eds.), Pere, T., Kasa, S., Pekkanen J., Pöllänen, J., Tarvainen, A-M. & Toropainen, V. 2011. Drilling and the Associated Drillhole Measurements of the Pilot Hole ONK-PH11. Eurajoki, Finland: Posiva Oy. Working Report 2011-03. 174 p.

Karvonen, T. 2008. Surface and Near-Surface Hydrological Model of Olkiluoto Island. 2008. Eurajoki, Finland: Posiva Oy. Working Report 2008-17. 90 p.

Karvonen, T. 2009. Increasing the Reliability of the Olkiluoto Surface and Near-Surface Hydrological Model. 2009. Eurajoki, Finland: Posiva Oy. Working Report 2009-7. 78 p.

Kemppainen, K., Ahokas, T., Ahokas, H., Paulamäki, S., Paananen, M., Gehör, S. & Front K. 2007. The ONKALO area model version 1. Eurajoki, Finland: Posiva Oy. Working Report 2007-71. 141 p.

192

Klockars, J., Vaittinen, T. & Ahokas, H. 2006. Hydraulic crosshole interference tests at Olkiluoto, Eurajoki in 2004 boreholes KR14-KR18 and KR15B-KR18B. Eurajoki, Finland: Posiva Oy. Working Report 2006-01. 61 p.

Korhonen, K-H., Gardemeister, R., Jääskeläinen, H., Niini, H. & Vähäsarja, P. 1974. Bedrock classification for civil engineering. Espoo, Technical Research Centre of Finland, Geotechnical Laboratory, Research Notes 12, 78 p.

Korhonen, K., Kuivamäki, A., Paananen, M. & Paulamäki, S. 2005. Lineament interpretation of the Olkiluoto area. Eurajoki, Finland: Posiva Oy. Working Report 2005-34. 67 p.

Kuivamäki, A. 2000. Lineament database of the Finnish potential repository sites for the calculation of bedrock movements induced by earthquakes. Helsinki, Finland: Posiva Oy. Working Report 2000-12. 32 p.

Kuivamäki, A. 2001. Revision of the lineament interpretation of Olkiluoto (in Finnish with an English abstract). Helsinki, Finland: Posiva Oy. Working Report 2001-28. 37 p.

Kuivamäki, A. 2005. Revision of the lineament interpretation of Olkiluoto in the light of the acoustic-seismic data from the adjacent marine areas. Eurajoki, Finland: Posiva Oy. Working Report 2005-16. 38 p.

Kukkonen, I., Paananen, M., Elo, S., Paulamäki, S., Laitinen, J., HIRE Working Group of the Geological Survey of Finland, Heikkinen, P. and Heinonen, S., 2010. HIRE Seismic Reflection Survey in the Olkiluoto area. Eurajoki, Finland: Posiva Oy. Working Report 2010-57. 62 p.

Lahti, M. (ed.), Ahokas, T., Nordbäck, N., Paananen, M., Paulamäki, S. & Vaittinen, T. 2009. The ONKALO Area Model version 1.1. Helsinki, Finland: Posiva Oy. Working Report 2009-113. 130 p.

Lahti, M. (ed.), Pere, T., Käpyaho, E., Toropainen, V., Tarvainen, A-M., Pöllänen, J. & Pekkanen J. 2011. Drilling and the Associated Drillhole Measurements of the Pilot Hole ONK-PH12. Eurajoki, Finland: Posiva Oy. Working Report 2011-02. 148 p.

Löfman, J. 1996. Groundwater flow modelling at the Olkiluoto site, flow under natural conditions. Helsinki, Finland: Posiva Oy. Work Report PATU-96-76e.

Löfman, J. 1999. Site scale groundwater flow in Olkiluoto. Helsinki, Finland: Posiva Oy. Posiva 99-03. ISBN 951-652-058-8. 121 p.

Löfman, J., Mészáros, F., Keto, V., Pitkänen, P. & Ahokas, H. 2009. Modelling of Groundwater Flow and Solute Transport in Olkiluoto - Update 2008. Eurajoki, Finland: Posiva Oy. Working Report 2009-78. 274 p.

Mancini, P., Karttunen, P., Lokkila, M. (eds.), Lamminmäki, T., Pekkanen, J., Pöllänen, J., Tarvainen, A-M., Toropainen, V., Kosunen, P. & Pere, T. 2010. Drilling and the Associated Drillhole Measurements of the Pilot Hole ONK-PH10. Eurajoki, Finland: Posiva Oy. Working Report 2010-21. 176 p.

193

Mattila, J. 2009. Constraints on the fault and fracture evolution at the Olkiluoto region. Eurajoki, Finland: Posiva Oy. Working Report 2009-130. 72 p.

Mattila, J., Aaltonen, I., Kemppainen, K. & Talikka, M. 2007.Geological mapping of investigation trench OL-TK11, the storage hall area. Eurajoki, Finland: Posiva Oy. Working report 2007-27, Posiva Oy, Eurajoki. 168 p.

Mattila, J., Aaltonen, I., Kemppainen, K., Wikström, L., Paananen, M., Paulamäki, S., Front, K., Gehör, S., Kärki, A., & Ahokas, T. 2008. Geological model of the Olkiluoto site version 1.0. Eurajoki, Finland: Posiva Oy. Working Report 2007-92. 509 p.

Milnes, A. G. 2006. Understanding brittle deformation at the Olkiluoto Site – Literature compilation for Site Characterisation and Geological modelling. Eurajoki, Finland: Posiva Oy. Working report 2006-25. 158 p.

Milnes, A.G., Aaltonen, I., Ahokas, T, Front, K., Gehör, S., Kemppainen, K., Kärki, A., Mattila, J., Paananen, M., Paulamäki, S. & Wikström. L., 2007. Geological data acquisition for site characterisation at Olkiluoto: framework for the phase of underground investigations. Eurajoki, Finland: Posiva Oy. Working Report 2007-32. 133 p.

Niinimäki, R. 2003. Core Drilling of Deep Borehole OL-KR24 at Olkiluoto in Eurajoki 2003. Eurajoki, Finland: Posiva Oy. Working Report 2003-52. 153 p.

Niva, J. 1996. Pumping tests in boreholes KR7 and KR8 at Olkiluoto in the spring 1995 (in Finnish with an English abstract). Helsinki, Finland: Posiva Oy. Work Report PATU-96-22.

Nordbäck, N. 2007. Geological mapping of investigation trench OL-TK14 at the Olkiluoto study site, Eurajoki, SW Finland. Eurajoki, Finland: Posiva Oy. Working Report 2007-98. 61 p.

NRC/CFCFF. 1996. Rock fractures and fluid flow. Contemporary understanding and applications. Report of the committee on fracture characterization and fluid flow, National Research Council, National Academy Press (Washington D.C.)

Paananen, M., Lehtonen, T. & Korhonen, K. 2007. Electrical model of Olkiluoto. Eurajoki, Finland: Posiva Oy. Working Report 2007-49. 99 p.

Palmén, J., Tammisto, E., & Ahokas, H. 2010. Database for Hydraulically Conductive Fractures – Update 2009. Eurajoki, Finland: Posiva Oy. Working Report 2010-13. 64 p + cd.

Paulamäki, S., Paananen, M., Gehör, S., Kärki, A., Front, K., Aaltonen, I., Ahokas, T., Kemppainen, K., Mattila, J. & Wikström, L., 2006. Geological model of the Olkiluoto Site, Version 0. Eurajoki, Finland: Posiva Oy. Working Report 2006-37. 355 p.

Pekkanen, J., Hurmerinta, E., Pöllänen, J. & Väisäsvaara, J. 2010. Difference flow and electrical conductivity measurements at the Olkiluoto site in Eurajoki, drillholes OL-

194

KR51, OL-KR52, OL-KR52B, OL-KR53 and OL-KR53B. Working report 2010-81. 202 p.

Pere, T. 2009. Fault-related local phenomena in the bedrock of Olkiluoto with particular reference to fault zone OL-BFZ100. Eurajoki, Finland: Posiva Oy. Working Report 2009-125. 98 p.

Pitkänen, P., Korkealaakso, J., Löfman, J., Keto, V., Lehtinen, A., Lindgren, S., Ikonen, A., Aaltonen, I., Koskinen, L., Ahokas, H., Ahokas, T. & Karvonen, T. 2008. Investigation plan for infiltration experiment in Olkiluoto. Eurajoki, Finland: Posiva Oy. Working Report 2008-53. 37 p.

Posiva Oy 2009. Olkiluoto Site Description 2008. Eurajoki, Finland: Posiva Oy. Posiva Report 2009-01. 714 p.

Pöllänen, J. 2006. Difference flow and electric conductivity measurements at the Olkiluoto site in Eurajoki, boreholes KR34 - KR39, KR37B and KR39B. Eurajoki, Finland: Posiva Oy. Working Report 2006-47. 236 p.

Pöllänen, J., Pekkanen, J. and Rouhiainen, P. 2005a. Difference flow and electric conductivity measurements at the Olkiluoto site in Eurajoki, boreholes KR19 – KR28, KR19B, KR20B, KR22B, KR23B, KR27B and KR28B. Eurajoki, Finland: Posiva Oy. Working Report 2005-52.

Pöllänen, J., Pekkanen, J. and Rouhiainen, P. 2005b. Difference flow and electric conductivity measurements at the Olkiluoto site in Eurajoki, boreholes KR29, KR29B, KR30, KR31, KR31B, KR32, KR33 and KR33B. Eurajoki, Finland: Posiva Oy. Working Report 2005-47.

Pöllänen, J. & Rouhiainen, P. 1996a. Difference flow measurements at the Olkiluoto site in Eurajoki, boreholes KR1-KR4, KR7 and KR8. Helsinki: Posiva Oy. Work Report PATU-96-43e. 44 p.

Pöllänen, J. & Rouhiainen, P. 1996b. Difference flow measurements at the Olkiluoto site in Eurajoki, boreholes KR9 and KR10. Helsinki, Finland: Posiva Oy. Work Report PATU-96-44e.

Pöllänen, J. & Rouhiainen, P. 2000. Difference flow measurements at the Olkiluoto site in Eurajoki, borehole KR11. Helsinki, Finland: Posiva Oy. Working Report 2000-38.

Pöllänen, J. & Rouhiainen, P. 2001. Difference flow and electric conductivity measurements at the Olkiluoto site in Eurajoki, boreholes KR6, KR7 and KR12. Helsinki, Finland: Posiva Oy. Working Report 2000-51. 150 p.

Pöllänen, J. & Rouhiainen, P. 2002a. Difference flow and electric conductivity measurements at the Olkiluoto site in Eurajoki, boreholes KR13 and KR14. Helsinki, Finland: Posiva Oy. Working Report 2001-42. 100 p.

195

Pöllänen, J. & Rouhiainen, P. 2002b. Difference flow and electric conductivity measurements at the Olkiluoto site in Eurajoki, boreholes KR15-KR18 and KR15B-KR18B. Helsinki, Finland: Posiva Oy. Working Report 2002-29. 134 p.

Pöllänen, J. & Rouhiainen, P. 2002c. Difference flow measurements at chosen depths in boreholes KR1, KR2, KR4 and KR11 at the Olkiluoto site in Eurajoki. Helsinki, Finland: Posiva Oy. Working Report 2002-42. 31 p.

Pöllänen, J. & Rouhiainen, P. 2002d. Difference flow and electric conductivity measurements at the Olkiluoto site in Eurajoki, extended part of borehole KR15. 31 p. Helsinki, Finland: Posiva Oy. Working Report 2002-43. 57 p.

Pöllänen, J. & Rouhiainen, P. 2002e. Difference flow and electric concuctivity measurements at the Olkiluoto site in Eurajoki, extended part of borehole KR15. Helsinki, Finland: Posiva Oy. Working Report 2002-43. 57 p.

Pöllänen, J. & Rouhiainen, P. 2005. Difference flow and electric conductivity measurements at the Olkiluoto site in Eurajoki, boreholes KR1, KR2, KR4, KR7, KR8, KR12 and KR14. Eurajoki, Finland: Posiva Oy. Working Report 2005-51.

Pöllänen, J. 2009. Difference flow and electric conductivity measurements at the Olkiluoto site in Eurajoki, drillholes OL-KR44, OL-KR44B, OL-KR45, OL-KR45B, OL-KR46, OL-KR47 and OL-KR48. Eurajoki, Finland: Posiva Oy. Working Report 2009-81. 366 p.

Rouhiainen, P. 2000. Electrical conductivity and detailed flow logging at the Olkiluoto site in Eurajoki, boreholes KR1-KR11. Helsinki, Finland: Posiva Oy. Working Report 99-72.

Rouhiainen, P., Pöllänen, J., Pekkanen, J. & Sokolnicki, M. 2005. Long-term pumping test in borehole KR24, flow measurements. Eurajoki, Finland: Posiva Oy. Working Report 2005-49.

Saksa, P., Ahokas, H., Nummela, J. & Lindh, J. 1998. Bedrock models of Kivetty, Olkiluoto and Romuvaara sites. Revisions of the structural models during 1997 (in Finnish with an English abstract). Helsinki, Finland: Posiva Oy. Work Report 98-12. 50 p.

Saksa, P. (ed.), Ahokas, H., Paananen, M., Paulamäki, S., Anttila, P., Front, K., Pitkänen, P., Hassinen, P & Ylinen, A. 1993. Bedrock model of the Olkiluoto area. Summary Report. Helsinki, Finland: Nuclear Waste Commission of Finnish Power Companies. Report YJT-93-15. 127 p + app.

Saksa, P., Nummela, J. & Ahokas, H. 1996. Bedrock model of Eurajoki Olkiluoto site. Supplemented and revised conceptual description in the year 1996 (in Finnish with an English abstract). Helsinki, Finland: Posiva Oy. Work Report PATU-96-46. 46 p.

Saksa, P., Vaittinen, T. & Nummela, J. 2002. Complementary modelling of the structures west of the proposed repository location, bedrock model v. 2001/2 (in Finnish with an English abstract). Eurajoki, Finland: Posiva Oy. Working Report 2002-46. 82 p.

196

Sievänen, U., Tasapuro, V., Ahokas, H., Hellä, P., Vaittinen, T., Nummela, J. & Tammisto, E. 2006. Updated hydrogeological statistics in ONKALO area and revised estimation of leakage water inflow into ONKALO tunnels. Eurajoki, Finland: Posiva Oy. Working Report 2006-29. 95 p.

SKB 2008. Site description of Forsmark at completion of the site investigation phase. SDM-site Forsmark. SKB TR-08-05. Svensk Kärnbränslehantering AB. 545 p.

Sokolnicki, M. & Pöllänen, J. 2008. Difference flow and electric conductivity measurements at the Olkiluoto site in Eurajoki, drillholes KR40, KR40B, KR41, KR41B, KR42, KR42B, KR43, KR43B and PP56. Eurajoki, Finland: Posiva Oy. Working Report 2008-65. 306 p.

Taivassalo, V. & Saarenheimo, A. 1991. Groundwter flow analysis for the VLJ repository. Helsinki, Finland: Nuclear Waste Commission of Finnish Power Companies. Report YJT-91-10.

Tammisto, E. & Palmén, J. 2010. Database for hydraulically conductive fractures – Update 2010. Eurajoki, Finland: Posiva Oy. Working Report (In print).

Tammisto, E., Palmén, J. & Ahokas, H. 2009. Database for hydraulically conductive fractures. Eurajoki, Finland: Posiva Oy. Working Report 2009-30. 110 p.

Tarvainen, A-M. 2008. Mise-a-la-masse measurements at Olkiluoto, 2007 and 2008. Eurajoki, Finland: Posiva Oy. Working Report 2008-30. 91 p.

Toropainen, V. 2008c. Core drilling of deep drillhole OL-KR49 at Olkiluoto in Eurajoki 2008. Eurajoki, Finland: Posiva Oy. Working Report 2008-80. 186 p

Toropainen, V. 2009a. Core drilling of deep drillhole OL-KR50 at Olkiluoto in Eurajoki 2008. Eurajoki, Finland: Posiva Oy. Working Report 2009-09. 194 p

Toropainen, V. 2009b. Core drilling of deep drillhole OL-KR51 at Olkiluoto in Eurajoki 2009. Eurajoki, Finland: Posiva Oy. Working Report 2009-73. 134 p

Toropainen, V. 2009c. Core drilling of deep drillhole OL-KR52 at Olkiluoto in Eurajoki 2009. Eurajoki, Finland: Posiva Oy. Working Report 2009-107. 132 p

Toropainen, V. 2009d. Core drilling of deep drillhole OL-KR53 at Olkiluoto in Eurajoki 2009. Eurajoki, Finland: Posiva Oy. Working Report 2009-111. 114 p

Vaittinen, T. & Ahokas, H. 2005. Long-term pumping test in borehole KR24 and pressure observations at Olkiluoto, Eurajoki in 2004. Eurajoki, Finland: Posiva Oy. Working Report 2005-40. 97 p.

Vaittinen, T., Ahokas, H. & Nummela, J. 2009b. Hydrogeological structure model of the Olkiluoto Site – update in 2008. Eurajoki, Finland: Posiva Oy. Working Report 2009-15. 275 p.

197

Vaittinen, T., Ahokas, H. & Nummela, J. 2010b. Hydrogeological analysis of pressure responses during excavation through HZ20 zones. Eurajoki, Finland: Posiva Oy. Working Report 2010-12. 74 p.

Vaittinen, T., Ahokas, H., Heikkinen, E., Hellä, P., Nummela, J., Saksa, P., Tammisto, E., Paulamäki, S., Paananen, M., Front, K. & Kärki, A. 2003. Bedrock model of the Olkiluoto site, version 2003/1. Eurajoki, Finland: Posiva Oy. Working Report 2003-43. 266 p.

Vaittinen, T., Ahokas, H., Klockars, J., Nummela, J., Pentti, E., Penttinen, T., Tammisto, E. Karvonen, T. & Lindgren, S. 2010a. Results of monitoring at Olkiluoto in 2009, Hydrology. Eurajoki, Finland: Posiva Oy. Working Report 2010-43. 272 p.

Vaittinen, T., Ahokas, H., Klockars, J., Nummela, J., Pentti, E., Penttinen, T., Pöllänen, J., Karvonen, T. & Lindgren, S. 2011. Results of monitoring at Olkiluoto in 2010, Hydrology. Eurajoki, Finland: Posiva Oy. Working Report 2011-43 (in prep.).

Vaittinen, T., Ahokas, H., Klockars, J., Nummela, J., Penttinen, T., Tammisto, E., & Karvonen, T. 2009a. Results of Monitoring at Olkiluoto in 2008 – Hydrology. Eurajoki, Finland: Posiva Oy. Working Report 2009-43. 236 p.

Vaittinen, T., Hellä, P., Nummela, J., Tammisto, E., Paulamäki, S. & Front, K. 2004a. Bedrock model of the Olkiluoto site, KR5 sub-volume, version 2002/1. Eurajoki, Finland: Posiva Oy. Working Report 2004-56. 99 p.

Vaittinen, T., Hellä, P., Nummela, J., Tammisto, E., Front, K. & Paulamäki, S. 2004b. Bedrock model of the Olkiluoto site, KR8 sub-volume, version 2002/2. Eurajoki, Finland: Posiva Oy. Working Report 2004-57. 101 p.

Vaittinen, T., Nummela J. & Ahokas, H. 2008. Compilation and analysis of hydrogeological responses to field activities in Olkiluoto. Eurajoki, Finland: Posiva Oy. Working Report 2008-03. 213 p.

Vaittinen, T., Saksa, P., Nummela, J., Palmén, J., Hellä, P., Ahokas, H. & Keskinen, J. 2001. Bedrock model of Olkiluoto site, revision 2001/1 (in Finnish with an English abstract). Helsinki, Finland: Posiva Oy. Working Report 2001-32. 190 p.

Vaittinen, T. & Pentti E, 2011. Compilation and analysis of hydrogeological responses to field activities at Olkiluoto in 2006-09. Eurajoki, Finland: Posiva Oy. Working Report (in prep.).

Väisäsvaara, J. 2010. Difference flow and electrical conductivity measurements at the Olkiluoto site in Eurajoki, drillholes OL-KR49, OL-KR50 and OL-KR50B. Eurajoki, Finland: Posiva Oy. Working Report 2010-16. 178 p.

Väisäsvaara, J. & Pöllänen, J. 2007. Difference flow and electric conductivity measurements at the Olkiluoto site in Eurajoki, boreholes KR25, KR25B and KR31. Eurajoki, Finland: Posiva Oy. Working Report 2007-16. 129 p.

198

Väisäsvaara, J., Pöllänen, J. & Sokolnicki, M. 2008. Monitoring measurements by difference flow method during the year 2006, drillholes OL-KR1, OL-KR4, OL-KR7, OL-KR8, OL-KR10, OL-KR14, OL-KR22, OL-KR22B, OL-KR27 and OL-KR28. Eurajoki, Finland: Posiva Oy. Working Report 2008-16. 394 p.

Ylinen, A., Väätäinen, A. & Takala, J. 1992. Interpretation of the 1991-1992 interference tests at the Eurajoki Olkiluoto site, Western Finland. Helsinki, Finland: Teollisuuden Voima Oy. TVO/Site investigations Work Report 92-68.

Öhberg, A. & Rouhiainen, P. 2000. Posiva Groundwater Flow Measuring Techniques. Helsinki, Finland: Posiva Oy. Posiva 2000-12. ISBN 951-652-098-7. 81 p.

Öhman, I., Heikkinen, E. & Lehtimäki, T. 2006. Seismic 2D reflection processing and interpretation of shallow refraction data. Eurajoki, Finland: Posiva Oy. Working Report 2006-114. 94 p.

Appendix 1 199

Drillhole logs in drillholes OL-KR1-OL-KR53

Depth = depth along drillhole length, m Lith. = lithology (cf. drillhole-specific legend, Aaltonen et al. 2010) Fract. Freq. = fracture frequency using a 1 metre long counting window, counted at every centimetre along the core Core loss = core loss sections based on drilling reports Oriented fractures = fractures with orientation, dip (symbol) and dip direction (tail) + fracture type (cf. drillhole-specific legend) Ri = intensity of fracturing (Ri I-II–Ri V) according to Finnish Engineering Geological Classification (cf. drillhole-specific legend, Korhonen et al. 1974, Gardemeister et al. 1976) 2003/1 = drillhole section of a zone following the criteria applied in 2003/1 model (Vaittinen et al. 2003) BFM v. 2.0 = drillhole section of a zone (core and influence zone) of the geological model version 2 (Aaltonen et al. 2010) HZ 2010 = drillhole section of a zone (zone intersection and transmissivity range) of the hydrogeological model version 2010 Local conn. = interpreted hydraulic connection to the ONKALO or to a site-scale zone or to another drillhole Flow, ml/h = flow into a drillhole during flow logging with pumping (cf. Chapter 3.2.1) Cemented = cemented drillhole section, usually made for stabilization of a drillhole during drilling Fracture T, m2/s = fracture specific transmissivity measured by flow logging (cf. Chapter 3.2.1) HTU T2m, m2/s = 2 m transmissivity measured by HTU tool T fracture orientation = orientation of hydraulically conductive fractures based on core mapping (cf. Chapter 3.2.1) Flow direction, ml/h = flow into or out of drillhole during flow logging without pumping (different colours are used for different measurements) Sections = applied combinations of packed-off sections References

Aaltonen, I. (ed.), Lahti, M., Engström, J., Mattila, J., Paananen, M., Paulamäki, S., Gehör, S., Kärki, A., Ahokas, T., Torvela, T. & Front, K. 2010. Geological Model of the Olkiluoto Site, Version 2. Eurajoki, Finland: Posiva Oy. Working Report 2010-70. 580 p.

Gardemeister, R., Johansson, S., Korhonen, P., Patrikainen, P., Tuisku, T. & Vähäsarja, P. 1976. The application of Finnish engineering geological bedrock classification (in Finnish). Espoo, Finland: Technical Research Centre of Finland, Geotechnical laboratory. Research note 25. 38 p.

Korhonen, K-H., Gardemeister, R., Jääskeläinen, H., Niini, H. & Vähäsarja, P. 1974. Engineering geological bedrock classification (in Finnish). Espoo, Finland: Technical Research Centre of Finland, Geotechnical laboratory. Research note 12. 78 p.

Vaittinen, T., Ahokas, H., Heikkinen, E., Hellä, P., Nummela, J., Saksa, P., Tammisto, E., Paulamäki, S., Paananen, M., Front, K. & Kärki, A. 2003. Bedrock model of the Olkiluoto site, version 2003/1. Eurajoki, Finland: Posiva Oy. Working Report 2003-43. 266 p.

casing

Packed-off sections: Comb. 1: 9.5.1992-11.8.1995

Lithology: Tonalitic-granodioritic-granitic gneiss

Mica gneiss

Mafic gneiss

Pegmatite/Pegmatitic granite

Veined gneiss

Diatexitic gneiss

Quartz gneiss

Ri: Ri III Ri IV Ri V

Flow rates:

Open Tight Filled Filled slick. Clay filled Grain filledFractures:

8.1996 (96-43e)Comb. 2: 6.11.1997-30.3.1998Comb. 3: 11.11.2003-19.1.2005, 11.6.2006 -

Structures: Intact rock Hydraulic feature Fracture zone

2.2006 (2008-16)

2.-3.2006 (2008-16)

BFM v. 2.0: BFZ Site scale BFZ Influence zone BFZ Repository scale HZ T rangeHZ 2010:

Depth

1:1400RiLith.

Fract.freq.

0 20

Oriented fractures

0 90

Core loss

OL-KR1 GEOLOGY

Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Com

b. 1

Com

b. 2

Com

b. 3

SectionsFlow ml/h

1 1e+006

Fracture T

-10 -3m2/s

CementedHTU T2m

-10 -3 m2/s

T fractureorientation

0 90

HYDROLOGY

2003/1HZ

2010Localconn.

BFMv. 2.0

MODELS

0

20

40

60

80

100

120

140

160

180

RH11_ALT135/45

R56_ALT191/59

1H151/4

RH11_ALT135/45

RH20A

L8

L7

L6

L8

L7

L8

L7

L6

HZ20A

HZ20B

HZ20,HZ002

BFZ084

BFZ020A

��

200

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

L5

L4

L6

L5

L5HZ20,HZ56

��

520

540

560

580

600

620

640

660

680

700

720

740

760

780

800

820

840

6R180/40

RH21165/19RH9141/49

8R50/40

9R160/50

5RH160/60

RH21165/19RH9141/49 L3

L2

L1

L4

L3

L2

L1

L4

L3

L2

L1

HZ099

HZ21+B

HZ20,HZ56

HZ20,HZ56

BFZ099

BFZ021

BFZ107

��

860

880

900

920

940

960

980

1000

��

casing

Comb. 1: 26.6.1991-12.5.1995

Lithology: Crushed

Tonalitic-granodioritic-granitic gneiss

Graphite rich

Mica gneiss

Mafic gneiss


Diatexitic gneiss

Veined gneiss


Flow rates:

Open Tight Filled Filled slick.

Clay filled Grain filled

Fractures:

6.1999 (99-72)

7.-8.2003 (2005-51)

Comb. 2: 18.11.1997-23.8.1998

Comb. 3: 29.2.2000-4.3.2002

20.7.-25.7.2005 (2006-39)

Structures: Intact rock Fracture zone Crushed zone

13.-14.3.2006 (2008-16)

Packed-off sections:

BFM v. 2.0:

2.-3.2007 (2008-40)

Comb. 4: 30.11.2007-

BFZ Site scale BFZ Influence zone BFZ Repository scale

9.5.-17.5.1996 (96-43e)

HZ 2010: HZ T range

Depth

1:1400Lith. Ri

Fract.freq.

0 20

Core loss

Oriented fractures

0 90

OL-KR2 GEOLOGY

Com

b. 1

Com

b. 2

Com

b. 3

Com

b. 4

Sections

Out

100000 1ml/h

Into

1 100000ml/h

Flow direction ml/h

1E+5 1 1E+5

Flow ml/h

1 1e+006ml/h

Cemented

Fracture T

-10 -3m2/s


0 90

HTU T2m

-10 -3 m2/s

HYDROLOGY

2003/1HZ

2010Localconn.

BFMv. 2.0

MODELS

0

20

40

60

80

100

120

140

L8 L8

L7

L6

KR24_3H

L8

L7

L6

HZ20,HZ002

Local_3

L8

L7

L6

BFZ139

BFZ020A

��

160

180

200

220

240

260

280

300

320

340

360

380

400

420

440

460

480

L7

L6

L5

RH20C115/24

RH20C115/24

RH20C115/24

5R75/60

RH20C115/24

RH20C115/24

RH20C115/24

L5

L4

L3

L2

L1

Local_2

L5

L4

BFZ025

BFZ009A

BFZ005

BFZ063

BFZ099

��

500

520

540

560

580

600

620

640

660

680

700

720

740

760

780

800

L5

L4

L3

L4

L3

6R270/25

7R170/40

RH21165/19RH21165/19

HZ099

HZ21,HZ21B

L3

L2

BFZ132

BFZ021

��

820

840

860

880

900

920

940

960

980

1000

1020

1040

L2

L1

L2

L1

9R170/40

L1

BFZ104

��

casing


Lithology: Stromatic gneiss

Mica gneiss


Veined gneiss

Diatexitic gneiss


Flow rates:

Unknown Open Tight Filled Filled slick.Fractures:

9.1996 (96-43e)Comb. 2: 25.11.1997-9.8.1998Comb. 3: 28.1.2002-8.9.2005, 10.5.2006 -

Intact rock Hydraulic feature Fracture zoneStructures:

BFZ Site scale BFZ Influence zone BFZ Repository scaleBFM v. 2.0:

7.1999 (99-72)

HZ 2010:

Depth

1:1400Lith. Ri

Fract.freq.

0 20

Core loss

Oriented fractures

0 90

OL-KR3 GEOLOGY

Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Com

b. 1

Com

b. 2

Com

b. 3

SectionsFlow ml/h

1 1e+006ml/h

Fracture T

-10 -3m2/s

Cemented


0 90

HYDROLOGY

2003/1HZ

2010Localconn.BFM

v. 2.0

MODELS

0

20

40

60

80

100

120

140

160

180

200

1H_ALT65/75

2R_ALT65/75

R10A155/41

L8

L7

L6

L8

L7

L8

L7

L6

BFZ020A

BFZ084

BFZ030

��

200

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

4R65/75

R72137/50

R72137/50

L5

L4

L3

L2

L1

L6

L5

L4

L3

L2

L1

L5

L4

L3

L2

L1

BFZ128

BFZ126

BFZ021

BFZ099

PL3804

PL3804

PL3804

PL3804

PL3804

��

casing

Intact rock Hydraulic feature Fracture zone Crushed zoneStructures:

Packed-off sections: Comb. 1: 18.9.1991-14.7.1995Comb. 2: 21.4.1998-8.6.1998Comb. 3: 17.4.2003-21.5.2003

Lithology: Crushed


Stromatic gneiss

Mica gneiss


Veined gneiss

Diatexitic gneiss

Quartz gneiss


Flow rates and

Fractures: Unknown Open Tight Filled

Filled slick. Clay filled Grain filled

6.2005 (2006-39)

11.2006 (2008-16)

2.2008 (2009-48)

Comb. 4: 6.6.2008-


fracture EC:

HZ 2010: HZ T range

28. - 29.10.2003 (2005-49)

17.3.-18.3.2004 (2005-49)

6.-7.1999 (99-72)

11.3.-9.4.1996 (96-43e)

Out

100000 1ml/h

Into

1 100000ml/h

Flow direction ml/h

1E+5 1 1E+5

Com

b. 1

Com

b. 2

Com

b. 3

Com

b. 4

SectionsT fractureorientation

0 90

Flow ml/h

1 1e+006ml/h

Cemented

Fracture T

-10 -3m2/s

HTU T2m

-10 -3 m2/s

HYDROLOGY

Depth

1:1400RiLith.

Oriented fractures

0 90

Fract.freq.

0 20

Core loss

OL-KR4 GEOLOGY

2003/1Localconn.

HZ2010

BFMv. 2.0

MODELS

0

20

40

60

80

100

120

140

KR24_3H

RH19A0/3

RH19B180/23

L8

L7

L6

L5

L8

L7

L6

L8

L7

L6

L5

L7

L6

L5

HZ19A

HZ19C

HZ19B

BFZ066

BFZ097

BFZ019A

BFZ019C

Local_4

��

160

180

200

220

240

260

280

300

320

340

360

380

400

420

440

460

480

RH20A137/18

RH20B126/12,RH20B_ALT

4H137/18

L4

L3

L2

L1

L5

L4

L4

L3

L4

L3

L2

HZ20A

HZ20B

BFZ020A

BFZ020B

��

500

520

540

560

580

600

620

640

660

680

700

720

740

760

780

800

820

7R160/20

RH21165/19

L3

L2

L1

L2

L1

L1

HZ21BFZ099

BFZ130

BFZ161

HZ20,HZ56

HZ56

��

820

840

860

880

900

9H230/70 HZ21B

��

casing



Mafic gneiss

Mica gneiss


Diatexitic gneiss

Veined gneiss


Unknown Tight Filled Filled slick. Grain filledFractures:

Comb. 2: 5.12.1997-10.8.1998

Comb. 3: 5.2.2002-

Structures: Intact rock Hydraulic feature Fracture zone Crushed zone


Flow rates:

HZ 2010: HZ T range

Depth

1:1400Lith. Ri

Fract.freq.

0 20

Core loss

Oriented fractures

0 90

OL-KR5 GEOLOGY

2003/1Localconn.

BFMv. 2.0

HZ2010

MODELS

Com

b. 1

Com

b. 2

Com

b. 3

Sections

Out

100000 1ml/h

Into

1 100000ml/h

Flow direction ml/h

1E+5 1 1E+5

Flow ml/h

1 1e+006ml/h


0 90

Fracture T

-10 -3m2/s

Cemented

HYDROLOGY

0

20

40

60

80

100

120

140

160

180

200

1H151/4

3H

2R160/35

L8

L7

L6

L5

L8

L7

L6

L8

L7

L6

L5

HZ20

HZ20

HZ20A

HZ001

��

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

520

540

560

RH9141/49

RH21165/19

RH21165/19

R2178/68

RH9141/49

6R120/30

RH21165/19

RH21165/19

L4

L3

L2

L1

L5

L4

L3

L2

L1

L4

L3

L2

L1

BFZ099

BFZ003

BFZ021

HZ099

HZ21B

HZ21

��

casing

Lithology: Metadiabase


Crushed

Mica gneiss


Diatexitic gneiss

Veined gneiss


Flow rates:

Unknown Open Tight Filled Filled slick. Clay filled Grain filledFractures:

8.2000 (2000-51)


BFZ Site scale BFZ Influence zone BFZ Repository scaleBFM v. 2.0: HZ 2010: HZ T range

Depth

1:1400Lith. Ri

Fract.freq.

0 20

Core loss

Oriented fractures

0 90

OL-KR6 GEOLOGY

Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Flow ml/h

1 1e+006ml/h


0 90

Cemented

Fracture T

-10 -3m2/s

HYDROLOGY

2003/1Localconn.

BFMv. 2.0

HZ2010

MODELS

0

20

40

60

80

100

120

140

160

180

1RH195/40

6R180/60

1RH195/40

2H151/4

3H151/4

4H151/4

5H280/66

7H180/60

BFZ041

BFZ099

HZ099

HZ001

��

200

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

520

8R180/60

9R265/88

RH3350/90

RH21165/19

12R 0/0

RH3350/90

RH21165/19

BFZ108

BFZ021

BFZ049

HZ21B

HZ21

��

540

560

580

600

13R170/50

��

casing

Packed-off sections: Comb. 1: 28.1.-3.8.1998

Lithology: Crushed


Mafic gneiss

Mica gneiss


Veined gneiss

Diatexitic gneiss


Flow rates:


2.1996 (96-43e)10.2000 (2000-51)

10.2003 (2005-51)7.2005 (2006-39)

11.2005 (2006-39)11.2005 (2006-39)


5.2006 (2008-16)

5.2006 (2008-16)1.2007 (2008-40)

Single packer: 8.8.2006-17.1.2007

Comb. 3: 4.7.-8.8.2007 Installed, but not working

Comb. 4: 15.6.2008-

BFZ Site scale BFZ Influence zone BFZ Repository scaleBFM v. 2.0: HZ 2010: HZ T range

Depth

1:1400RiLith.

Fract.freq.

0 20

Core loss

Oriented fractures

0 90

OL-KR7 GEOLOGY

Com

b. 1

Com

b. 3

Com

b. 2

Com

b. 4

Sections

Out

100000 1ml/h

Into

1 100000ml/h

Flow direction ml/h

1E+5 1 1E+5

Fracture T

-10 -3m2/s

Flow ml/h

1 1e+006ml/h

HTU T2m

-10 -3 m2/s


0 90

HYDROLOGY

2003/1Localconn.

HZ2010

BFMv. 2.0

MODELS

0

20

40

60

80

100

120

140

160

RH19B180/23

1RH

RH19B180/23

L7

L6

L2

L1

L4

L3

L8

L7

L6

HZ19B

BFZ019A

BFZ109

��

180

200

220

240

260

280

300

320

340

360

380

400

420

440

460

480

R56190/59

RH20A137/18

4H137/18

5H137/18

6H137/18

7RH126/12


L5

L4

L3

L2

L1

HZ20,HZ56

L2

L1

L5

L4

L3

L2

HZ20A

HZ20B

BFZ020A

BFZ020B

BFZ084

BFZ039

��

500

520

540

560

580

600

620

640

660

680

700

720

740

760

780

800

RH21165/19

RH21165/19

RH21165/19

RH21165/19

L1

HZ21

BFZ099

��

casing



Stromatic gneiss

Mafic gneiss

Mica gneiss


Diatexitic gneiss

Quartz gneiss


Flow rates:


10.1996 (96-43e)

3.2004 (2005-51)

Comb. 2: 12.3.-24.6.2002

12.2005 (2006-39)

12.2005 (2006-39)


6.2006 (2008-16)

6.2006 (2008-16)

7.2007 (2008-40)

Comb. 3: 30.4.-2.6.2003Comb. 4: 31.10.2007 -


11.2002 (2005-51)

HZ 2010: HZ T range

Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Com

b. 1

Com

b. 2

Com

b. 3

Com

b. 4


0 90

Flow ml/h

1 1e+006ml/h

Fracture T

-10 -3m2/s

HTU T2m

-10 -3 m2/s

HYDROLOGY

Depth

1:1400Lith. Ri

Fract.freq.

0 20

Core loss

Oriented fractures

0 90

OL-KR8 GEOLOGY

2003/1Localconn.

BFMv. 2.0

HZ2010

MODELS

0

20

40

60

80

100

120

140

160

L7

L6

L5

L4

L4

L3

RH19A0/3

RH19A0/3

7RH

8R

1H

4H150/40

5H150/40

6H150/40

L4

L3

HZ19

BFZ074

BFZ127

HZ19A

HZ19C

��

180

200

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

L3

L2

L1

L2

L1

L4

L3

L2

RH19B180/23

RH19B180/23

11R

12R

L2

BFZ015

BFZ048

BFZ016

BFZ020A

HZ19B

HZ20A

��

500

520

540

560

580

600

L1

RH20B_A

L1

BFZ020B HZ20B

��

casing



Mafic gneiss

Mica gneiss


Veined gneiss

Diatexitic gneiss

Quartz gneiss


Flow rates:

Tight Filled Filled slick. Clay filled Grain filledFractures:

9.-10.1996 (96-44e)Comb. 2: 15.2.02-26.10.06, 20.12.2006 -


BFZ Site scale BFZ Influence zone BFZ Repository scaleBFM v. 2.0

7.-8.1999 (99-72)

HZ 2010: HZ T range

Depth

1:1400Lith. Ri

Fract.freq.

0 20

Oriented fractures

0 90

OL-KR9 GEOLOGY

Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Com

b. 1

Com

b. 2

Com

b. 3

SectionsFlow ml/h

1 1e+006ml/h


0 90

Fracture T

-10 -3m2/s

HYDROLOGY

2003/1Localconn.

BFMv. 2.0

HZ2010

MODELS

0

20

40

60

80

100

120

140

160

180

200

1HRH19B180/23

RH19B180/23

RH19A

L8

L7

L6

L7

L6

L5

BFZ011

BFZ019C

HZ19C

HZ19

HZ19

��

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

520

540

RH20A137/18

RH20B126/12

L5

L4

L3

L2

L4

L3

L2

BFZ020A

BFZ020B

HZ20A

HZ20B

HZ20

HZ20

��

560

580

600

RH20B_A

RH20B_A

L1

L1

BFZ175

HZ20

��

casing



Mica gneiss


Veined gneiss

Diatexitic gneiss


Flow rates:

Tight Filled Filled slick. Grain filledFractures:

5.1996 (96-44e)

9.-10.2005 (2006-39)

Structures: Intact rock Hydraulic feature Crushed zone

2.-3.2006 (2008-16) Comb. 2: 9.2.2007-17.3.2008Single packer: 21.3.-15.5.2006; 26.6.2006-15.1.2007


Comb. 3: 30.3.2008-

HZ 2010: HZ T range

Out

100000 1ml/h

Into

1 100000ml/h

Flow direction ml/h

1E+5 1 1E+5

Com

b. 1

Com

b. 3

Single pk

Com

b. 2

SectionsFlow ml/h

1 1e+006ml/h

Fracture T

-10 -3m2/s

CementedHTU T2m

-10 -3 m2/s


0 90

HYDROLOGY

Depth

1:1400RiLith.

Oriented fractures

0 90

Fract.freq.

0 20

Core loss

OL- KR10 GEOLOGY

2003/1Localconn.

BFMv. 2.0

HZ2010

MODELS

0

20

40

60

80

100

120

140

160

180

L8

L7

L8

L7

L2

L1

L8

L7

BFZ019C

BFZ081

BFZ134

HZ19A

HZ19C

��

180

200

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

RH20A137/18


3R160/20

RH20A137/18

L6

L5

L4

L3

L2

L6

L5

L4

L3

L2

L6

L5

L4

L3

L2

BFZ020A

BFZ043

BFZ020B

BFZ135

HZ20A

HZ20B

HZ20,HZ56

HZ20,HZ56

HZ20,HZ56

��

520

540

560

580

600L1

L1

L1BFZ136

HZ20,HZ56

� � ��

casing



Crushed

Stromatic gneiss

Mica gneiss


Diatexitic gneiss

Veined gneiss


Flow rates:


8.-10.1999 (2000-38) Comb. 1: 16.12.2002-4.10.2007 and 20.4.2008-4.5.2009



Comb. 2: 20.5.2009-11.3.20103.2010 (2010-xx)

HZ 2010: HZ T range

Depth

1:1400Lith. Ri

Fract.freq.

0 20

Oriented fractures

0 90

OL-KR11 GEOLOGY

Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Com

b. 1

Com

b. 2

Com

b. 3

SectionsFlow ml/h

1 1e+006ml/h


0 90

Fracture T

-10 -3m2/s

HYDROLOGY

2003/1Localconn.

BFMv. 2.0

HZ2010

MODELS

0

20

40

60

80

100

120

140

160

180

1RH 1RH

L8

L7

BFZ056

L8

L7

HZ19C

� � ��

200

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

520

2R170/10

3R

L6

L5

L4

Local_5

BFZ125

BFZ020A

BFZ175

L6

L5

L4

� � ��

540

560

580

600

620

640

660

680

700

720

740

760

780

800

820

840

RH21165/19

5R150/40

RH21165/19

L3

L2

BFZ099

L3

L2

HZ21

� ��

860

880

900

920

940

960

980

1000

6R315/75

L1

BFZ105

L1

� � ��

casing



Mafic gneiss

Mica gneiss


Veined gneiss

Diatexitic gneiss


Flow rates:

Unknown Tight Filled Filled slick. Clay filled Grain filledFractures:

7.2000 (2000-51) Comb. 1: 19.1.2004 -

9.2003 (2005-51)


BFM v. 2.0: BFZ Site scale BFZ Influence zone BFZ Repository scale HZ 2010: HZ T range

Depth

1:1400Lith. Ri

Fract.freq.

0 20

Core loss

Oriented fractures

0 90

OL-KR12 GEOLOGY

Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Com

b. 1

Com

b. 2

Com

b. 3

SectionsFracture T

-10 -3m2/s


0 90

Flow ml/h

1 1e+006ml/h

HTU T2m

-10 -3 m2/s

HYDROLOGY

2003/1Localconn.

HZ2010

BFMv. 2.0

MODELS

0

20

40

60

80

100

120

140

160

180

L8

L7

L6

RH19A

RH26137/20

4R 0/0

1H

RH19A

RH26137/20

HZ19C

BFZ137

BFZ067

BFZ138

BFZ139

BFZ020A

HZ19

HZ20,Local_

� � ��

200

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

520

L5

L4

5R245/60

RH20C115/24

RH20C115/24

RH20C115/24

9R 0/45

10R160/35

11R160/35

12R175/15

RH20C115/24

RH20C115/24

RH20C115/24

BFZ096

BFZ020B

BFZ209

BFZ070

Local_2

� � ��

540

560

580

600

620

640

660

680

700

720

740

760

780

L3

L2

L1

13R

14R140/25

15R

16R

RH21165/19

RH21165/19

19R175/50

RH21165/19

RH21165/19

HZ099

HZ21

HZ21B

BFZ099

BFZ094

BFZ021

BFZ131

BFZ107

� � ��

casing


Crushed

Mica gneiss

Mafic gneiss


Veined gneiss

Diatexitic gneiss


Flow rates:


6.-8.2001 (2001-42)


Packed-off sections: Comb. 1: 7.9.2007 -


Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Com

b. 2

Com

b. 3

Com

b. 1

SectionsFlow ml/h

1 1e+006ml/h


0 90

Fracture T

-10 -3m2/s

HTU T2m

-10 -3 m2/s

HYDROLOGY

Depth

1:1400RiLith.

Fract.freq.

0 20

Core loss

Oriented fractures

0 90

OL-KR13 GEOLOGY

2003/1Localconn.

HZ2010

BFMv. 2.0

MODELS

0

20

40

60

80

100

120

140

160

180

KR24_3H

RH26137/20

1H160/20

RH26137/20

4H140/30

L5

Local_3

BFZ218

BFZ020A

BFZ041

� � ��

200

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

RH20C115/24

RH20C115/24

7R180/20

8R90/70

9R130/70

10R150/35

RH20C115/24

RH20C115/24

L4

L3

L2

L1

Local_2

HZ001

HZ099

BFZ009A

BFZ072

BFZ110A

BFZ216

BFZ005

BFZ028

BFZ045A

BFZ099

BFZ069

� � ��

casing



Mica gneiss

Mafic gneiss


Veined gneiss


Flow rates:


8.-9.2001 (2001-42)

9.2003 (2005-51)


1.2005 (2006-39)

2.2006 (2008-16)

3.2007 (2008-40)

Single packer: 30.5.-7.6.2006; 20.6.2006-12.3.2007

BFM v. 2.0: BFZ Site scale BFZ Influence zone BFZ Repository scale

Packers for infiltration test: 28.11.2008-

HZ 2010: HZ T range

Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Com

b. 1

Com

b. 3

Com

b. 2

SectionsFlow ml/h

1 1e+006ml/h

Fracture T

-10 -3m2/s


0 90

HTU T2m

-10 -3 m2/s

HYDROLOGY

Depth

1:1400RiLith.

Fract.freq.

0 20

Core loss

Oriented fractures

0 90

OL-KR14 GEOLOGY

2003/1Localconn.

BFMv. 2.0

HZ2010

MODELS

0

20

40

60

80

100

120

140

160

180

1H

2H

3H

RH19ARH19A

R78115/38

L3

L2

L1

L2

L1

L3

L2

L1

BFZ019C

BFZ020A

HZ19A

HZ19C

��

200

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

BFZ025

BFZ063

BFZ005

BFZ036

BFZ046

��

casing casing B



Crushed

Mica gneiss

Mafic gneiss


Veined gneiss

Diatexitic gneiss


Flow rates:


12.2001-1.2002 (2002-29) Comb. 1: 16.8.2004-16.4.2007 and 4.5.2008-

6.-7.2002 (2002-43) B: Comb. 1: 18.8.2004-24.4.2007

B: 12.2001-3.2002 (2002-29)


B: Comb. 2: 27.6.2008-


7.2007 (2009-23)

HZ T rangeHZ 2010:

Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Com

b. 1

B:C

omb. 1

Com

b. 2

B:C

omb. 2


0 90

Flow ml/h

1 1e+006ml/h

Fracture T

-10 -3m2/s

HTU T2m

-10 -3 m2/s

HYDROLOGY

Depth

1:1400Lith. Ri

Fract.freq.

0 20

Core loss

Oriented fractures

0 90

OL-KR15 (+B) GEOLOGY

2003/1Localconn.

BFMv. 2.0

HZ2010

MODELS

0

20

40

60

80

100

120

140

160

180

200

L6

L5

L4

L3

L2

L1

RH19A

R78115/38

KR24_3H

KR24_3H

KR24_3H

KR15B_4H

2H120/40

L2

L1

BFZ020A

HZ19A

HZ19C

HZ19

HZ19

HZ19,HZ002

HZ20,Local_1

��

200

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

520

L2

L14R90/60

BFZ025

BFZ005

BFZ046

HZ20

HZ20

��

casing casing B



Mafic gneiss


Veined gneiss

Diatexitic gneiss

Quartz gneiss


Flow rates:

Tight Filled Filled slick. Clay filledFractures:

12.2001-1.2002 (2002-29) Comb. 1: 2.9.2004-12.4.2007 and 25.6.2008-

B: 12.2001-3.2002 (2002-29) B: Comb. 1: 8.9.2004-24.4.2007

Structures: Intact rock Hydraulic feature

B: Comb. 2: 26.6.2008-


Depth

1:1400Lith. Ri

Fract.freq.

0 20

Core loss

Oriented fractures

0 90


IntoOut

Flow direction ml/h

1E+5 1 1E+5

Com

b. 1

B:C

omb.1

Com

b. 2

B:C

omb.2

SectionsFlow ml/h

1 1e+006ml/h


0 90

Fracture T

-10 -3m2/s

HTU T2m

-10 -3 m2/s

HYDROLOGY

2003/1Localconn.

BFMv. 2.0

HZ2010

MODELS

0

20

40

60

80

100

120

140

160

L6

L5

L4

L3

L2

L1

L3

L2

L1

RH19A

KR24_3H

RH19A

L2

L1

BFZ050

BFZ020A

HZ19A

HZ19C

HZ20A

HZ19

HZ19

HZ19

HZ19,HZ002

HZ20

HZ20,Local_1

��

casing casing B

Packed-off sections: Comb. 1: 23.8.-9.11.2004, 6.11.2008-

Lithology: Mica gneiss Pegmatite/Pegmatitic granite Veined gneiss Diatexitic gneiss


Flow rates:


12.2001-2.2002 (2002-29)

B: 12.2001-4.2002 (2002-29)


B: Comb. 1: 25.8.2004-24.4.2007B: Comb. 2: 6.7.2008-


Depth

1:1400RiLith.

Fract.freq.

0 20

Core loss

Oriented fractures

0 90


Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Com

b. 1

Com

b. 2

B: C

omb.1

B: C

omb.2


0 90

Flow ml/h

1 1e+006ml/h

Fracture T

-10 -3m2/s

HTU T2m

-10 -3 m2/s

HYDROLOGY

2003/1Localconn.

BFMv. 2.0

HZ2010

MODELS

0

20

40

60

80

100

120

140

RH19A

R78115/38

RH19A

2H

L6

L5

L4

L3

L2

L1

L2

L1

L2

L1

BFZ050

BFZ020A

BFZ050

HZ19A

HZ19C

HZ19

HZ19

HZ19,HZ002

HZ20

HZ20

HZ20,Local_1

��

casing casing B



Mica gneiss

Mafic gneiss


Veined gneiss

Diatexitic gneiss


Flow rates:

Tight Filled Filled slick.Fractures:

12.2001-2.2002 (2002-29)12.2001-4.2002 (2002-29)


Comb. 1: 18.8.-27.9.2004; 10.11.2004-10.4.2007; 1.4.2008-B: Comb. 1: 2.9.2004-24.4.2007B: Comb. 2: 8.4.2008-

HZ T rangeHZ 2010:

Depth

1:1400Lith. Ri

Fract.freq.

0 20

Core loss

Oriented fractures

0 90


Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

B: C

omb.1

Com

b. 1

Com

b. 2

B: C

omb.2


0 90

Flow ml/h

1 1e+006ml/h

Fracture T

-10 -3m2/s

HTU T2m

-10 -3 m2/s

HYDROLOGY

2003/1Localconn.

HZ2010

BFMv. 2.0

MODELS

0

20

40

60

80

100

120

KR18B_1R

RH19A

KR24_3H

KR24_ 3H

KR18B_4H

KR18B_5RH

L5

L4

L3

L2

L1

L2

L1

L3

L2

L1

HZ19A

HZ19C

HZ19

HZ19

HZ19

HZ19

HZ19,HZ002

HZ20

��

casing casing B



Mica gneiss

Mafic gneiss


Diatexitic gneiss

Veined gneiss

Quartz gneiss


Flow rates:


7.2004 (2005-52)B: 9.2002 (2005-52)


Comb. 2: 25.11.2003-2.6.2004

BFM v. 2.0 BFZ Site scale BFZ Influence zone BFZ Repository scale

Comb. 3: 7.9.2009-

HZ 2010: HZ T range

Depth

1:1400RiLith.

Oriented fractures

0 90

Fract.freq.

0 20

Core loss


Into

1 100000

Out

100000 1

Flow direction ml/h

1E+5 1 1E+5

Flow ml/h

1 1e+006ml/h


0 90

Fracture T

-10 -3m2/s

Sections

Com

b.3

Com

b.2

Com

b.1

HYDROLOGY

2003/1Localconn.

BFMv. 2.0

HZ2010

MODELS

0

20

40

60

80

100

120

140

160

180

200

220

KR19B_3

1R170/30

2RH170/30

3R170/30

4R170/30

RH20C115/24

KR19B_10/20

KR19B_20/20

KR19B_4

6H160/10

L4

L3L4

Local_2

L8

L7

L6

L5

L4

BFZ007

BFZ041

BFZ095

BFZ044

BFZ006

BFZ110B

BFZ005

BFZ087

BFZ078

BFZ133

BFZ082

BFZ083HZ001

��

240

260

280

300

320

340

360

380

400

420

440

460

480

500

520

540

R2178/68

8R160/20

9R170/30

RH21165/19

11R167/20

12R120/30

L2

L1

L3

L2

L1

L3

L2

L1

BFZ099

BFZ003

BFZ021

BFZ065

HZ099

HZ21B

��

casing casing B



Stromatic gneiss

Mafic gneiss

Mica gneiss


Veined gneiss

Diatexitic gneiss

Quartz gneiss



Comb. 1: 17.5.2004 -



Flow rates:

HZ T rangeHZ 2010:

Depth

1:1400Lith. Ri

Fract.freq.

0 20

Core loss

Oriented fractures

0 90


Out

100000 1ml/h

Into

1 100000ml/h

Flow direction ml/h

1E+5 1 1E+5

Com

b. 1

Com

b. 2

Com

b. 3

SectionsFlow ml/h

1 1e+006ml/h


0 90

Fracture T

-10 -3m2/s

HYDROLOGY

2003/1Localconn.

BFMv. 2.0

HZ2010

MODELS

0

20

40

60

80

100

120

140

160

180

KR20B_2R

3R150/40

KR20B_1H

1RH

2H

RH80167/39

L7

L6

L5

L4

L3

BFZ020A

BFZ020A

BFZ068

HZ20A

HZ20B

HZ20,Local_1

HZ20

HZ20

HZ20

��

200

220

240

260

280

300

320

340

360

380

400

420

440

460

480

RH9141/49

7R160/30

RH9141/49

L2

L1

BFZ025

BFZ099

BFZ099

BFZ065

HZ099

HZ099

��

casing


Mica gneiss


Veined gneiss

Diatexitic gneiss

Quartz gneiss


Flow rates:


8.2004 (2005-52)

Structures: Intact rock Fracture zone


Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Fracture T

-10 -3m2/s


0 90

Flow ml/h

0.4 400000ml/h

Com

b. 1

Com

b. 2

Com

b. 3

HYDROLOGY

Depth

1:1400Lith. Ri

Fract.freq.

0 20

Core loss

Oriented fractures

0 90

OL-KR21 GEOLOGY

2003/1HZ

2010Localconn.

BFMv. 2.0

MODELS

0

20

40

60

80

100

120

140

160

180

200

RH80167/39

2 190/40

��

220

240

260

280

300

3

4 180/40

BFZ009B

BFZ005

��

casing casing B


Lithology: Crushed


Mica gneiss

Mafic gneiss


Diatexitic gneiss

Veined gneiss


Flow rates:


3.2004 (2005-49)

B: 5.2005 (2006-39)


2.2005 (2006-39)

2.2005 (2006-39)

3.2005 (2006-39)

3.2005 (2006-39)4.2006 (2008-16)4.2006 (2008-16)

B: 4.2006 (2008-16)

3.-4.2007 (2008-40)

B: 3.-4.2007 (2008-40)

Comb. 2: 4.6.2007-26.8.2009, 23.9.2009-


9.2009 (2010-48)

10.-11.2002 (2005-52)

HZ 2010: HZ T range

Depth

1:1400Lith. Ri

Fract.freq.

0 20

Core loss

Oriented fractures

0 90


Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Com

b. 1

Com

b. 2

Com

b. 3

SectionsFlow ml/h

1 1e+006ml/h

Fracture T

-10 -3m2/s

HTU T2m

-10 -3 m2/s


0 90

HYDROLOGY

2003/1Localconn.

BFMv. 2.0

HZ2010

MODELS

0

20

40

60

80

100

120

140

L3

3RH130/10

RH19B180/23

KR22B_1135/48

KR22B_2135/48

RH24139/48

1RH139/48

2R120/60

4RH

L8

L7

L6

L5

L4

L3

BFZ106 0

BFZ058 0

BFZ059 0

BFZ019A 0

HZ19A

HZ19C

HZ19B

HZ19

HZ19

HZ19

HZ19

��

160

180

200

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

L2

L1

5R

RH20A137/18


L2

L1

BFZ019C 1

BFZ122 0

BFZ129 0

BFZ020A 1

BFZ020B 1

BFZ100

HZ20A

HZ20B

��

casing casing B



Mafic gneiss

Mica gneiss


Veined gneiss

Diatexitic gneiss


Flow rates:


6.2003 (40-295m)Comb. 2: 16.12.2004-B: Comb. 1: 11.2.-28.7.2004


8.2004 (295-451m) (2005-52)


Depth

1:1400

Oriented fractures

0 90

Fract.freq.

0 20

Lith. Ri

Core loss


Com

b. 1

Com

b. 2

B: C

omb 1

Sections

Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Flow ml/h

1 1e+006ml/h

Fracture T

-10 -3m2/s


0 90

HYDROLOGY

2003/1Localconn.

BFMv. 2.0

HZ2010

MODELS

0

20

40

60

80

100

120

140

160

180

200

KR23_1R

KR23_2H

KR23_3H

RH19A

RH19A

KR23_6H

KR23_7H

KR23_8H

RH19B

KR23B_1

KR23B_2 45/30

L7

L6

L5

L4

L3

L2

L7

L6

L5

L4

L3

L2

L1

HZ19

HZ19

BFZ017

BFZ019C

HZ19A

HZ19C

HZ19B

��

200

220

240

260

280

300

320

340

360

380

400

420

440

460

KR23_10R

KR23_11R

RH20A

RH20A

RH20B

L1

L2

L1

BFZ203

BFZ100

BFZ020A

BFZ100

HZ20A

��

casing




Stromatic gneiss

Mafic gneiss

Mica gneiss


Veined gneiss

Diatexitic gneiss




Flow rates:

HZ 2010: HZ T range

Depth

1:1400RiLith.

Fract.freq.

0 20

Core loss

Oriented fractures

0 90

OL-KR24 GEOLOGY

Out

100000 1

Into

1 100000

Flow direction ml/h

1E+5 1 1E+5

Com

b. 2

Com

b. 3

Com

b. 1

SectionsFlow ml/h

1 1e+006ml/h


0 90

Fracture T

-10 -3m2/s

HYDROLOGY

2003/1Localconn.

BFMv. 2.0

HZ2010

MODELS

0

20

40

60

80

100

120

140

160

180

200

220

KR24_1RH

KR24_2H

KR24_3H

RH19A

RH19B

L2

L1

Local_4

BFZ200

BFZ019A

BFZ019C

HZ19A

HZ19C

��

240

260

280

300

320

340

360

380

400

420

440

460

480

500

520

540

RH20A

RH20B

RH20B_ALT

BFZ098

BFZ020A

BFZ020B

HZ20A

HZ20B

��

casing casing B

Hydraulic feature Fracture zone Crushed zoneStructures:

Packed-off sections: Comb. 1: 27.1.-2.8.2004; 8.12.04-28.9.2005; 5.10.2006 -


Mica gneiss


Diatexitic gneiss

Veined gneiss


Flow rates:B: Comb. 1: 27.1.-4.8.2004


7.-8.2006 (2007-16)

B: 8.2006 (2007-16)

BFM v. 2.0: BFZ Site scale BFZ Influence zone BFZ Local scale HZ T rangeHZ 2010:

Depth

1:750RiLith.

Fract. freq.

0 20

Core loss

Oriented fractures

0 90


Com

b. 1

B: C

omb. 1

Com

b. 2

Sections

Into

1 100000ml/h

Out

100000 1

Flow direction ml/h

1E+5 1 1E+5

Flow ml/h

1 1e+006ml/h

Fracture T

-10 -3m2/s


0 90

HYDROLOGY

2003/1Localconn.

BFMv. 2.0

HZ2010

MODELS

0

20

40

60

80

100

L8

L7

L6

L5

L4

L2

L1

BFZ019A

HZ19A

HZ19C

RH19A

KR25_2H

RH19B

��

120

140

160

180

200

220

240

260

280

BFZ056

BFZ019C

BFZ034

BFZ100

BFZ140

BFZ100

HZ19B

BFZ100

KR25_4H

KR25_5R

KR25_6R

KR25_7R

��

300

320

340

360

380

400

420

440

460

L3

L2

L1

HZ20

BFZ020A

BFZ020B

HZ20A

HZ20B

RH20A

RH20A

RH20B

RH20B_ALT

��

480

500

520

540

560

580

600

BFZ219

KR25_12R

KR25_13R

��

casing

Intact rock Hydraulic feature Crushed zoneStructures:

Lithology: Mafic gneiss

Mica gneiss


Diatexitic gneiss


Flow rates:


12.2003.-2.2004 (2005-52)


Depth

1:1400RiLith.

Fract.freq.

0 20

Oriented fractures

0 90

Core loss

OL-KR26 GEOLOGY

Out

100000 1ml/h

Into

1 100000ml/h

Flow direction ml/h

1E+5 1 1E+5Sections

Flow ml/h

1 1e+006ml/h

Com

b. 1

Com

b. 2

Com

b. 3


0 90

Fracture T

-10 -3m2/s

HYDROLOGY

2003/1Localconn.

HZ2010

BFMv. 2.0

MODELS

0

20

40

60

80

100

KR26_1H

KR26_2H

KR26_3R

BFZ100BFZ100

��

casing casing B


Mafic gneiss

Mica gneiss


Veined gneiss

Diatexitic gneiss


Flow rates:


12.2003-2.2004 (2005-49)

B: 6.2004 (2005-49)

5.2005 (2006-39)


2.2006 (2008-16)

4.-5.2007 (2008-40)3.-4.2008 (2009-48)

Comb. 1: 25.4.2008-Packed-off sections:


Depth

1:1400RiLith.

Fract.freq.

0 20

Core loss

Oriented fractures

0 90


Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Flow ml/h

1 1e+006ml/h

Sections

Com

b. 2

Com

b. 3

Com

b. 1

Fracture T

-10 -3m2/s

HTU T2m

-10 -3 m2/s


0 90

HYDROLOGY

2003/1Localconn.

BFMv. 2.0

HZ2010

MODELS

0

20

40

60

80

100

120

140

160

180

200

KR27B_1RH

KR27B_2R

KR27_1H

KR27_2H

KR27_3R

RH19A

RH19B

L8

L7

L6

L5

L4

BFZ146

BFZ146

BFZ106

BFZ012

BFZ013

HZ146

HZ19A

HZ19C

��

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

520

540

KR27_5R

KR27_6RH

KR27_7R

KR27_8R

KR27_9R

KR27_10R

KR27_11R

KR27_12R

HZ20

L3

L2

L1

BFZ141

BFZ019C

BFZ048

BFZ053

BFZ058

BFZ055

BFZ129

BFZ020A

HZ19B

HZ20A

��

casing casing B



Mafic gneiss

Mica gneiss


Diatexitic gneiss

Veined gneiss


Flow rates:


1.-3.2004 (2005-52)6.2004 (2005-52)

12.2005 (2006-39)

6.2006 (2008-16)

6.2007 (2008-40)

5.-6.2007 (2008-40)



Depth

1:1400RiLith.

Fract.freq.

0 20

Oriented fractures

0 90

Core loss


Out

100000 1ml/h

Into

1 100000ml/h

Flow direction ml/h

1E+5 1 1E+5

Flow ml/h

0.1 1e+006ml/h

SectionsFracture T

-10 -3m2/s

Com

b. 1

Com

b. 2

Com

b. 3

HTU T2m

-10 -3 m2/s


0 90

HYDROLOGY

2003/1Localconn.

HZ2010

BFMv. 2.0

MODELS

0

20

40

60

80

100

120

140

160

180

KR28B_1R

RH19A

KR28_1H

KR28_2H

RH19B

L8

L7

L6

L5

L4

HZ19A

HZ19C

HZ19B

BFZ100

HZ19B

BFZ019A

BFZ019C

BFZ100

��

200

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

RH20A

RH20B_ALT,RH20B

L3

L2

HZ20A

HZ20B

BFZ020A

BFZ020B

��

520

540

560

580

600

620

640

KR28_6R

KR28_7R

KR28_8R

HZ20,HZ56

L1

��

casing casing B

Packed-off sections: Comb. 1: 5.1.2006 -

Lithology: Mafic gneiss

Mica gneiss


Veined gneiss

Diatexitic gneiss


Flow rates:


10.-11.2004 (2005-47)

B: 12.2004 (2005-47)



Depth

1:1400RiLith.

Fract.freq.

0 20

Oriented fractures

0 90

Core loss


Out

100000 1ml/h

Into

1 100000ml/h

Flow direction ml/h

1E+5 1 1E+5

Com

b. 1

Com

b. 2

Com

b. 3

SectionsFlow ml/h

1 1e+006ml/h

Fracture T

-10 -3m2/s


0 90

HYDROLOGY

2003/1Localconn.

BFMv. 2.0

HZ2010

MODELS

0

20

40

60

80

100

120

140

160

180

200

KR29B_1R

KR29B_2H

KR29B_3R

KR29_1RH

KR29_2R

L8

L7

L6

BFZ142

HZ19A

HZ19C

HZ20A

��

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

520

540

560

RH20A

RH20B_ALT,RH20B

RH20B_ALT,RH20B

KR29_6R

KR29_7R

L5

L4

L3

HZ20

BFZ020A

BFZ020B

BFZ039

BFZ024

HZ20B

��

580

600

620

640

660

680

700

720

740

760

780

800

820

840

860

880

900

KR29_8RH

KR29_9R

KR29_10R

KR29_11R

KR29_12R

KR29_13R

KR29_14R

KR29_15R

L2

L1

BFZ099

BFZ130

BFZ091

HZ039

HZ21

��

casing



Veined gneiss

Diatexitic gneiss


Flow rates:

Tight Filled Filled slick. Grain filledFractures:

10.2004 (2005-47)



4.-5.2009 (2010-48)

HZ T rangeHZ 2010:

Depth

1:1400Lith. Ri

Fract.freq.

0 20

Oriented fractures

0 90

OL-KR30 GEOLOGY

Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5Sections

Flow ml/h

1 1e+006ml/h

Com

b. 1

Com

b. 2

Com

b. 3

Fracture T

-10 -3m2/s


0 90

HYDROLOGY

2003/1Localconn.

HZ2010

BFMv. 2.0

MODELS

0

20

40

60

80

KR30_1H

RH19B

RH19A

KR30_4RH

HZ19A

HZ19C

BFZ019A

BFZ019C

BFZ143

��

casing casing B


Mica gneiss


Diatexitic gneiss


Flow rates:

Open Tight Filled Filled slick. Grain filledFractures:

10.-11.2004 (2005-47)B: 11.2004 (2005-47)

4.-5.2006 (2007-16)



7.2009 (2010-48)

HZ 2010: HZ T range

Depth

1:1400Ri

Oriented fractures

0 90

Fract.freq.

0 20

Core loss

Lith.


Into

1 100000ml/h

Out

1 100000ml/h

Flow direction ml/h

1E+5 1 1E+5

Fracture T

-10 -3m2/s

Sections

Com

b. 1

Com

b. 2

Com

b. 3

Flow ml/h

1 1e+006ml/h


0 90

HTU T2m

-10 -3 m2/s

HYDROLOGY

2003/1Localconn.

BFMv. 2.0

HZ2010

MODELS

0

20

40

60

80

100

120

140

160

180

KR31B_1H

RH19A,KR24_2H

RH19B

KR31_3RH

BFZ035

BFZ144

BFZ058

BFZ019C

HZ19A

HZ19C

HZ19B

��

200

220

240

260

280

300

320

340

��

casing



Veined gneiss

Diatexitic gneiss

Quartz gneiss


Flow rates:


11.-12.2004 (2005-47)



Depth

1:1400Lith. Ri

Fract.freq.

0 20

Core loss

Oriented fractures

0 90

OL-KR32 GEOLOGY

Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5Sections

Flow ml/h

1 1e+006ml/h

Com

b. 1

Com

b. 2

Com

b. 3


0 90

Fracture T

-10 -3m2/s

HYDROLOGY

2003/1Localconn.

BFMv. 2.0

HZ2010

MODELS

0

20

40

60

80

100

120

140

160

180

KR32_1H

KR32_2R

RH19A

KR32_4R

KR32_5R

HZ20,Local_1

HZ002

BFZ139

BFZ020A

BFZ006

BFZ050

BFZ041

��

casing casing B

Lithology: Metadiabase


Mafic gneiss


Veined gneiss


Flow rates:


12.2004-1.2005 (2005-47)B: 1.2005 (2005-47)



Depth

1:1400Lith.

Fract. freq.

0 20

Oriented fractures

0 90

Core loss

Ri


Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5Sections

Flow ml/h

1 1e+006ml/h

Com

b. 1

Com

b. 2

Com

b. 3


0 90

Fracture T

-10 -3m2/s

HYDROLOGY

Localconn.2003/1

BFMv. 2.0

HZ2010

MODELS

0

20

40

60

80

100

120

140

160

180

200

HZ001

��

220

240

260

280

300

BFZ099

BFZ030

BFZ031

��

casing



Diatexitic gneiss





Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Flow ml/h

1 1e+006ml/h

Sections

Com

b. 1

Com

b. 2

Com

b. 3


0 90

Fracture T

-10 -3m2/s

HYDROLOGY

Depth

1:1400Ri

Fract.freq.

0 20

Core loss

Oriented fractures

0 90

Lith.

OL-KR34 GEOLOGY

2003/1Localconn.

BFMv. 2.0

HZ2010

MODELS

0

20

40

60

80

100

BFZ100

BFZ019A

BFZ100

HZ19A

��

casing

Lithology: Pegmatite/Pegmatitic granite

Diatexitic gneiss


Flow rates:


8.2009 (2010-48)



Out

100000 1ml/h

Into

1 100000ml/h

Flow direction ml/h

1E+5 1 1E+5

Flow ml/h

1 1e+006ml/h


0 90

Sections

Com

b. 1

Com

b. 2

Com

b. 3

Fracture T

-10 -3m2/s

HYDROLOGY

Depth

1:1400Ri

Fract.freq.

0 20

Core loss

Oriented fractures

0 90

Lith.

OL-KR35 GEOLOGY

2003/1 BFMv. 2.0

HZ2010

Localconn.

MODELS

0

20

40

60

80

100

BFZ019A

HZ19A

HZ19A

��

casing

Lithology: Pegmatite/Pegmatitic granite

Diatexitic gneiss


Flow rates:


6.2005 (2006-47)



Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Flow ml/h

1 1e+006ml/h

Sections

Com

b. 1

Com

b. 2

Com

b. 3

Fracture T

-10 -3m2/s


0 90

HYDROLOGY

Depth

1:1400Ri

Fract.freq.

0 20

Core loss

Oriented fractures

0 90

Lith.

OL-KR36 GEOLOGY

2003/1Localconn.

HZ2010

BFMv. 2.0

MODELS

0

20

40

60

80

100

120

140

160

180

200

HZ19A

HZ19CBFZ019A

BFZ019C

��

casing casing B



Mica gneiss


Veined gneiss

Diatexitic gneiss


Flow rates:


B: 4.2006 (2006-47)

4.2006 (2006-47) Packed-off sections: Comb. 1: 14.9.2007-


Out

100000 1ml/h

Into

1 100000ml/h

Flow direction ml/h

1E+5 1 1E+5

Flow ml/h

1 1e+006ml/h

Sections

Com

b. 1

Com

b. 2

Com

b. 3


0 90

Fracture T

-10 -3m2/s

HYDROLOGY

Depth

1:1400Ri

Fract. freq.

0 20

Oriented fractures

0 90

Lith.

Core loss


2003/1Localconn.

HZ2010

BFMv. 2.0

MODELS

0

20

40

60

80

100

120

140

160

180

L5

L4

L3

BFZ100

HZ19A

HZ19C

HZ19B

BFZ100

BFZ019A

��

200

220

240

260

280

300

320

340

L2

L1

HZ19B

ONKALO

ONKALO

��



Mica gneiss

Mafic gneiss


Veined gneiss

Diatexitic gneiss




Out

100000 1ml/h

Into

1 100000ml/h

Flow direction ml/h

1E+5 1 1E+5

Flow ml/h

0.4 400000ml/h

Sections

Com

b. 1

Com

b. 2

Com

b. 3


0 90

Fracture T

-10 -3m2/s

HYDROLOGY

Depth

1:1400Ri

Fract.freq.

0 20

Core loss

Oriented fractures

0 90

Lith.

OL-KR38 GEOLOGY

2003/1Localconn.

BFMv. 2.0

HZ2010

MODELS

0

20

40

60

80

100

120

140

160

180

200

220

BFZ019A

BFZ019C

HZ19A

HZ19B+C

��

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

520

BFZ020A

BFZ020B

HZ20A

HZ20B

��

K-feldspar porphyry


Mica gneiss


Diatexitic gneiss

Veined gneiss

Lithology:

Fractures: Open Tight Filled Filled slick. Clay filled Grain filled

Ri: Ri III Ri IV

Flow rates:B: 11.2005 (2006-47)10.-11.2005 (2006-47) Packed-off sections: Comb. 1: 24.9.2007-16.2.2010



casing casing B

4.2010 (Draft)

HZ 2010: HZ T range

Depth

1:1400

Oriented fractures

0 90

RiFract.freq

0 20

Core loss

Lith.


Out

100000 1ml/h

Into

1 100000ml/h

Flow direction ml/h

1E+5 1 1E+5

Com

b. 1

Com

b. 2

Com

b. 3

SectionsFlow ml/h

1 1e+006ml/h

Fracture T

-10 -3m2/s

HTU T2m

-10 -3 m2/s


0 90

HYDROLOGY

2003/1Localconn.

BFMv. 2.0

HZ2010

MODELS

0

20

40

60

80

100

120

140

160

180

L8

L7

L6

L5

L4

BFZ020A

BFZ176

BFZ084

HZ20A

HZ20B

HZ20

HZ20

HZ20

��

200

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

L3

L2

L1

BFZ130

BFZ177

PL3804

PL3804

PL3804

��

casing casing B

Intact rock Crushed zoneStructures:

Lithology: K-feldspar porphyry


Mica gneiss

Mafic gneiss


Veined gneiss

Diatexitic gneiss

Ri:

Flow rates:


3.2006 (2008-65)11.2006 (2008-65)B: 12.2006 (2008-65)

Ri III Ri IV Ri V


5.-6.2009 (2010-48)10.5.-1.6.2010 (Draft)

HZ 2010: HZ T range

Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Com

b. 1

Com

b. 2

Com

b. 3

SectionsFlow ml/h

1 1e+006ml/h

Fracture T

-10 -3m2/s


0 90

HTU 2m

-10 -3 m2/s

HYDROLOGY

Depth

1:1400Lith.

Fract.freq.

0 20

Oriented fractures

0 90

Core loss

Ri


2003/1Localconn.

HZ2010

BFMv. 2.0

MODELS

0

20

40

60

80

100

120

140

160

180

HZ146

BFZ146

BFZ146

BFZ178

BFZ179

BFZ180

��

200

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

520

HZ19C

BFZ181

BFZ019C

BFZ159

BFZ106

BFZ048

BFZ011

BFZ012

��

520

540

560

580

600

620

640

660

680

700

720

740

760

780

800

820

840

HZ20B

BFZ020A

BFZ182

BFZ020B

BFZ013

BFZ020B

BFZ183

BFZ053

��

860

880

900

920

940

960

980

1000

1020

HZ21

BFZ184

BFZ208

��

casing casing B



Mica gneiss


Diatexitic gneiss

Veined gneiss


Flow rates:


9.2006 (2008-65)

B: 10.2006 (2008-65)


Depth

1:1400

Oriented fractures

0 90

Lith.Fract.freq.

0 20

Ri

Core loss


Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Com

b. 1

Com

b. 2

Com

b. 3

SectionsFractureT

-10 -3m2/s

Flow ml/h

1 1e+006ml/h


0 90

HYDROLOGY

HZ20102003/1

Localconn.

BFMv. 2.0

MODELS

0

20

40

60

80

100

120

140

160

180

200

BFZ185

BFZ020A

��

220

240

260

280

300

320

340

360

380

400

BFZ041

��

casing casing B



Mica gneiss


Veined gneiss

Diatexitic gneiss


Flow rates:


B: 9.2006 (2008-65)

8.-9.2006 (2008-65)

1.2007 (2008-65)


Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Com

b. 1

Com

b. 2

Com

b. 3

SectionsFlow ml/h

1 100000ml/h

Fracture T

-10 -3m2/s


0 90

HTU 2m

-10 -3 m2/s

HYDROLOGY

Depth

1:1400Lith.

Fract.freq.

0 20

RiOriented fractures

0 90

Core loss


Localconn.2003/1

BFMv. 2.0

HZ2010

MODELS

0

20

40

60

80

100

120

140

160

180

200

BFZ019C

BFZ186

BFZ020A

BFZ100

HZ19C

BFZ100

��

220

240

260

280

300

320

340

360

380

400

BFZ020B

BFZ175

BFZ041

BFZ209

BFZ210

��

casing casing B

Intact rock Hydraulic feature Fractured CrushedStructures:


Mafic gneiss


Diatexitic gneiss

Veined gneiss


Flow rates:


6.-7.2007 (2008-65)B: 7.2007 (2008-65)


Com

b. 1

Com

b. 2

Com

b. 3

Sections

Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Flow ml/h

1 1e+006ml/h

Fracture T

-10 -3m2/s


0 90

HYDROLOGY

Depth

1:1400Lith.

Fract.freq.

0 20


0 90

Core loss


Localconn.2003/1

BFMv. 2.0

HZ2010

MODELS

0

20

40

60

80

100

120

140

160

180

200

BFZ099

BFZ187

BFZ188

HZ001

HZ21B

��

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

520

BFZ189

BFZ190

BFZ191

BFZ192

BFZ021 HZ21

��

540

560

580

600

620

640

660

680

700

720

740

760

780

800

820

840

860

HZ008

��

880

900

920

940

960

980

1000

��

casing casing B



Mica gneiss

Mafic gneiss


Veined gneiss

Diatexitic gneiss

Quartz gneiss


Flow rates:

Tight Filled Filled slick. Clay filledFractures:

8.-9.2007 (2009-81)B: 9.2007 (2009-81)

Comb. 1: 18.6.2008-25.2.2010Packed-off sections:

30.8.-2.9.2010 (Draft)

HZ 2010: HZ T rangeBFM v. 2.0: BFZ Site scale BFZ Influence zone BFZ Repository scale

Com

b. 2

Com

b. 3

Com

b. 1

Sections

Out

100000 1ml/h

Into

1 100000ml/h

Flow dir. ml/h

1E+5 1 1E+5

Flow ml/h

1 1e+006ml/h

Fracture T

-10 -3m2/s


0 90

HYDROLOGY

Depth

1:1400

Fract. freq.

0 20

Lith.

Core loss


0 90


2003/1HZ

2010BFMv. 2.0

Localconn.

MODELS

0

20

40

60

80

100

120

140

160

180

200

L3

L2

L1

HZ19A

HZ19C

��

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

520

540

560

BFZ193

��

560

580

600

620

640

660

680

700

720

740

760

780

800

820

840

860

880

900

HZ20B

BFZ194

BFZ020A

BFZ020B

BFZ195

BFZ217

BFZ152

BFZ196

��

casing casing B

Intact rock Hydraulic CrushedFeatures:



Mica gneiss


Diatexitic gneiss

Veined gneiss


Flow rates:


B: 11.2007 (2009-81)10.-11.2007 (2009-81)

HZ 2010: HZ T rangeBFM v. 2.0: BFZ Site scale BFZ Influence zone BFZ Repository scale

Com

b. 1

Com

b. 2

Com

b. 3

Sections

into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Flow ml/hDraft

1 1e+006ml/min


0 90

Fracture T

-10 -3m2/s

HTU 2m

-10 -3 m2/s

HYDROLOGY

Localconn.2003/1

BFMv. 2.0

HZ2010

MODELS

Depth

1:1400Lith.

Fract.freq.

0 20

Oriented fracturesDraft

0 90

Ri

Core loss


0

20

40

60

80

100

120

140

160

180

200

BFZ197

BFZ146

BFZ152

BFZ198

BFZ178

BFZ199

BFZ151

BFZ160

HZ146

��

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

520

540

� ��

540

560

580

600

620

640

660

680

700

720

740

760

780

800

820

840

860

BFZ019C

��

880

900

920

940

960

980

1000

1020

��

casing casing B

Intact rock Crushed zoneStructures:



Veined gneiss

Quartz gneiss


Flow rates:

Open Tight Filled Filled slick. Clay filledFractures:

7.-8.2007 (2009-81)

BFM v. 2.0: BFZ Site scale BFZ Influence zone BFZ Repository scaleHZ 2010: HZ T range

Com

b. 1

Com

b. 2

Com

b. 3

Sections

Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Flow ml/h

1 1e+006ml/h


0 90

Fracture T

-10 -3m2/s

HYDROLOGY

Localconn.2003/1

BFMv. 2.0

HZ2010

MODELS

Depth

1:1400Lith.

Fract.freq.

0 20


0 90

Ri

Core loss


0

20

40

60

80

100

120

140

160

180

200

Local_5

HZ19C

��

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

520

540

BFZ020A

BFZ175

��

540

560

580

600

��

casing casing B

Intact rock Hydraulic Fractured CrushedFeatures:


Mica gneiss


Veined gneiss

Diatexitic gneiss


Flow rates:


1.2008 (2009-81)


Com

b. 1

Com

b. 2

Com

b. 3

Sections

Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Flow ml/h

1 1e+006ml/h


0 90

Fracture T

-10 -3m2/s

HYDROLOGY

Localconn.2003/1

BFMv. 2.0

HZ2010

MODELS

Depth

1:1400Lith. Core loss


0 90

Ri

Fract.freq.

0 20


0

20

40

60

80

100

120

140

160

180

200

BFZ215

BFZ211

��

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

520

540

BFZ175

BFZ099

BFZ021

HZ21

��

540

560

580

600

620

640

660

680

700

720

740

760

780

800

820

840

860

BFZ212

BFZ213

HZ21

��

880

900

920

940

960

980

1000

BFZ214

��

casing



Mica gneiss


Veined gneiss

Diatexitic gneiss

Quartz gneiss


Flow rates:

Open Tight Filled Filled slick. Clay filledFractures:

10.2007 (2009-81)3.2008 (2009-81)

BFM v. 2.0: HZ 2010: HZ T rangeBFZ Site scale BFZ Influence zone BFZ Repository scale

Com

b. 1

Com

b. 2

Com

b. 3

Sections

Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Flow ml/hDraft

1 1e+006ml/h


0 90

Fracture T

-10 -3m2/s

HYDROLOGY

Localconn.2003/1

BFMv. 2.0

HZ2010

MODELS

Depth

1:1400

Fract. freq.

0 20

Oriented fractures

0 90

Lith.

Core loss

Ri

OL-KR48 GEOLOGY

0

20

40

60

80

100

120

140

160

180

200

BFZ200

BFZ019A HZ19A

HZ19B+C

� ��

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

520

BFZ201

BFZ020A

BFZ020B

HZ20A

HZ20B

��

Intact rock Hydraulic Fractured Crushed Crushed+HydStructures:



Mica gneiss


Diatexitic gneiss

Veined gneiss

Quartz gneiss


Flow rates:

Unknown Open Tight Filled Filled slick. Clay filled GraiFractures:

casing

7.1.-9.1.2009 (2010-16)

HZ 2010: HZ T rangeBFZ Site scale BFZ Influence zone BFZ Repository scaleBFM v. 2.0:

Com

b. 1

Com

b. 2

Com

b. 3

Sections

Out

100000 1ml/h

Into

1 100000ml/h

Flow direction ml/h

1E+5 1 1E+5

Flow ml/h

1 1e+006ml/h


0 90

Fracture T

-10 -3m2/s

HYDROLOGY

Depth

1:1400Lith. Ri

Oriented fractures

0 90

Frac.freq.

0 20

Core loss

OL-KR49 GEOLOGY

Localconn.2003/1

HZ2010

BFMv. 2.0

MODELS

0

20

40

60

80

100

120

140

160

180

200

��

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

520

540

HZ146

BFZ146

��

540

560

580

600

620

640

660

680

700

720

740

760

780

800

820

840

860

��

880

900

920

940

960

980

1000

1020

1040

1060

��

Intact rock Fract+Hyd Hydraulic Crushed Crushed+HydStructures:


K-feldspar porphyry

Mica gneiss


Veined gneiss

Diatexitic gneiss

Quartz gneiss



HZ 2010: HZ T rangeBFZ Site scale BFZ Influence zone BFZ Repository scaleBFM v. 2.0:

1-2.2009 (2010-16)Flow rates:

casing Casing B

B: 5.2009 (2010-16)

Com

b. 1

Com

b. 2

Com

b. 3

Sections

Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Flow ml/h

1 1e+006


0 90

Fracture T

-10 -3m2/s

HYDROLOGY

Depth

1:1400

Lith. Frac.freq.

0 20


0 90

Core loss

OL-KR50+B GEOLOGY

Localconn.2003/1

HZ2010

BFMv. 2.0

MODELS

0

20

40

60

80

100

120

140

160

180

200

��

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

520

540

HZ146

BFZ146

��

540

560

580

600

620

640

660

680

700

720

740

760

780

800

820

840

860

��

880

900

920

940

��

Intact rock Crushed Crushed+HydStructures:


K-feldspar porphyry

Mica gneiss


Diatexitic gneiss

Veined gneiss

Quartz gneiss


Flow rates:


casing

10.2009 (2010-81)

HZ 2010: HZ T range

BFMv. 2.0

Localconn.2003/1

HZ2010

MODELS

Com

b. 1

Com

b. 2

Com

b. 3

Sections

Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Flow ml/h

1 1e+006ml/h


0 90

Fracture T

-10 -3m2/s

HYDROLOGY

Depth

1:1400

Oriented fractures

0 90

Fract.freq.

0 20

Lith. Ri

Core loss

OL-KR51 GEOLOGY

0

20

40

60

80

100

120

140

160

180

200

� ��

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

520

540

HZ146

HZ146

��

540

560

580

600

620

640

��

Intact rock Crushed Crushed+HydStructures:


K-feldspar porphyry

Mica gneiss

Mafic gneiss


Diatexitic gneiss

Veined gneiss

Quartz gneiss


Flow rates:


8.-9.2009 (2010-81)

B: 1.-2.2010 (2010-81)

HZ 2010: HZ T range

casing Casing B

BFMv. 2.0

Localconn.2003/1

HZ2010

MODELS

Com

b. 1

Com

b. 2

Com

b. 3

Sections

Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Flow ml/h

1 1e+006ml/h


0 90

Fracture T

-10 -3m2/s

HYDROLOGY

Depth

1:1400

Frac.freq.

0 20

Oriented fractures

0 90

Lith. Ri

Core loss

OL-KR52 +B GEOLOGY

0

20

40

60

80

100

120

140

160

180

200

��

220

240

260

280

300

320

340

360

380

400

420HZ146

��

Fract+Hyd Intact rock Crushed Crushed+HydStructures:


K-feldspar porphyry

Mica gneiss

Mafic gneiss


Diatexitic gneiss

Veined gneiss

Quartz gneiss


Flow rates:


11-12.2009 (2010-81)

B: 1.2010 (2010-81)

casing Casing B

BFMv. 2.0

HZ2010

Localconn.2003/1

MODELS

Com

b. 1

Com

b. 2

Com

b. 3

Sections

Into

1 100000ml/h

Out

100000 1ml/h

Flow direction ml/h

1E+5 1 1E+5

Flow ml/h

1 100000ml/h


0 90

Fracture T

-10 -3m2/s

HYDROLOGY

Depth

1:1400

Oriented fractures

0 90

Frac.freq.

0 20

Lith. Ri

Core loss

OL-KR53+B GEOLOGY

0

20

40

60

80

100

120

140

160

180

200

��

220

240

260

280

300

��

�

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Documents

Hydrogeological Structure Model of the Olkiluoto Site – Update in