ERMSAR 2012, Cologne March 21 – 23, 2012 Pascal PILUSO (CEA) Seong-Wan HONG (KAERI) Matjaz LESKOVAR (JSI) Presentation by François BOUSSARD (CEA) On behalf

ERMSAR 2012, Cologne March 21 – 23, 2012

Pascal PILUSO (CEA)Seong-Wan HONG (KAERI)

Matjaz LESKOVAR (JSI)Presentation by François BOUSSARD (CEA)

On behalf of SERENA members

2011 CSARP/MCAPSep. 20-23, 2011

[email protected]. [email protected], [email protected]

Status of SERENA-2

mailto:[email protected]


Scope of SERENA Project Status of the SERENA Project

Experimental Program Analytical program

Concluding Remarks

Outline


Scope of SERENA Project

Phase 1 (started October 2003, 4 years) Mainly calculations evidencing some

discrepancy between the different codes but remaining under the max stress level design of a reactor vessel

The same exercise applied to ex-vessel concrete led to insufficient safety margins for the containment.

Phase 2 (started October 2007, 4 years) Carry out confirmatory research required to

reduce uncertainties on these phenomena and thus to an acceptable level for risk assessment.


Scope of SERENA Project- Partners in Phase 2

Started from Oct., 2007 and will be continued for four years.

KAERI and CEA: Operation agents

18 Orgs. from 11 countries are participating: Belgium (Tractebel-Engineering SUEZ) Canada (AECL) Finland (VTT) France (CEA, IRSN, EDF) Germany (GRS, IKE) Japan (JNES) Korea (KAERI, KINS, KMU) Slovenia (JSI) Sweden (SSM, KTH) Switzerland (PSI) USA (US NRC, UWM)


Scope of SERENA Project-Main Objective of Phase 2 (1)

To reduce the scatter of the predictions for Steam Explosion in order to be able to increase the confidence in the calculated

containment safety margins for ex-vessel reactor case conditions.

Experimental tests (TROI and KROTOS facilities) by: Providing the missing experimental data on one key

FCI phenomena: the prototypical corium composition (“material effect”) using a large spectrum of corium melts representative of accident scenarios.

Providing innovative experimental data : spatial and size distribution of corium melts and void fraction during premixing and at the time of explosion and its dynamics.


Scope of SERENA Project-Main Objective of Phase 2 (2)

Experimental tests (TROI and KROTOS facilities) by: Improving modelling on the basis of the new data to

obtain consistent predictions of cavity loading by ex-vessel steam explosion.

Doing work oriented for elaboration on the major effects which are related to the explosion strength.

Analytical work by: Improving of FCI models/codes for use in reactor

analyses by complementing the work performed in Phase-1 through integrating the results of the Phase-2 Experimental program.

Doing work oriented for safety analysis and quantification of the major effects which reduce the explosion strength.


Release hook

Tungsten crucible and load

Thermal screens

Pyrometer

Isolation ball valve

Rupture wire #1

Heating element

Rupture wire #2

Puncher

Pressure vessel

Test tube

Release cone

Guide tube

Pyrometer

Water level (1145 mm)

Trigger

Force sensor

Dynamic pressure transducers (K0-K6) Sacrificial thermocouples (ZT1-ZT10) Lateral thermocouples (TT1-TT6) Pressure transducers (C1-C3)

Level swell

Ground floor

Basement

X-Ray window positions in different tests

•5 kg of melt•1-D geometry•New release device•Fast X-ray camera•External trigger

•20 kg of melt•2-D geometry•Intermediate catcher•Tomography•External trigger

Prototypical corium compositions

Status of SERENA Project-Experimental Program (1)

R.F. Generator150 kW

ColdCrucible

Furnace VesselID 1300

706

110

403

727

1020

716

Pressure VesselID 2,000

450

764

500

460

100

634

470

1214

220

250

289

`

`

10

274

1930

250

50050

057

0

946

200

TestSection

IVT101

IVT102

IVT103

IVT104

IVT209

IVDP101

IVDP102

IVDP103

IVDP104

IVT201

VFDP103

VFDP102

VFDP101

PVT001PVDP001

PVT002PVDP002

PVT003PVDP003

200

200

200

200

200

300

PVSP005PVT005PVDP005GAS005

PVSP004PVT004PVDP004GAS004

FVSP001

Intermediatemelt catcherand release

valve assembly

852

IVT202

IVT203

IVT204

IVT205

IVT206

IVT207

IVT208

Ar gas supplyfor aerosol removal

FVT

Pyrometer-1

Pyrometer-2

200

295.46

125

L60050, nozzle

-460

0

570

1000

1500

2000

3790

4810Elevation (mm)

30 t

1750

Catcher,

Nozzle,

Water,

T.S.,

(Unit : mm)

Pyrometer-3

KROTOS Facility (CEA)

TROI Facility(KAERI)


Status of the SERENA Project-Experimental program (2)

The complementary and innovative features of KROTOS (CEA) and TROI (KAERI) facilities are used

KROTOS for investigating the FCI characteristics of prototypical corium melts in one-dimensional geometry and fine characterization of the premixing thanks to X-Ray fast radioscopy able to distinguish corium, water and void. Essential for computer code model

improvement TROI for investigating the FCI behaviour in reactor-like

conditions by having more mass and multi-dimensional melt water interaction geometry. Suitable for validating the capability of

the computer codes in reactor-like situations.


Status of KROTOS : experimental Program (3)

KROTOS TROI

1 Challenging conditions

High melt superheat High system pressure(0.4 MPa, Room water temp.)

High system pressure (0.4 MPa) Reduced free fall (Melt jet velocity) and thick melt jet (Room water T.)

Mat 1: 70%UO2-30%ZrO2

2 Geometry effect Effect of geometry by comparison between KROTOS and TROI

Standard conditions: jet of diameter 3 cm

Large jet at penetration (5 cm)

Mat 1: 70%UO2-30%ZrO2

3 Reproducibility tests

Idem Test 2 Idem Test 2

4 Material effectOxidic composition



Mat 2: 80%UO2-20%ZrO2

5 Material effect Oxidation/composition



Mat 3: 70%UO2-15%ZrO2 + 15%Zr6 Material effect

Large solidus/liquidus T

Standard conditions. Effect of fission product: higher melt superheat

Large jet at penetration (5 cm).

Mat 4: 70%UO2-30%ZrO2 +FP+iron oxide

Performed

Performed

Performed

Performed (KS March 14th)

Performed

Status

Performed


KAERI and CEA performed all 6 TS and KS tests Triggered steam explosions in five tests out of 6 tests were

observed (KS and TS). The repeatable tests (TS-2 and TS-3) showed that many parameters

including dynamic pressure almost agree with each other. KS4 and TS-4 tests (80%UO2-20%ZrO2) both show larger explosion

load than other TS or KS tests respectively, except TS-6 and possibly KS6 (under analysis).

TS-5 test with added metallic Zr produced steam spike before triggering and no explosion was observed. KS-5 produced a triggered explosion (X-Ray confirmed).

TS-6 which has the lowest liquidus temperature and the largest solidification range shows the largest explosion of TS tests. KS6 is still under analysis (last week performed) and an energetic explosion has been observed.

Status of the SERENA Project- Experimental Program (5)


755

KROTOS KS3 - KS4

: 10 cm PF le 31/08/2010

K0-50

K2395

K1195

K3595

K4795

K5995

K61195

ZT2395

PyJ1637

Vidéo1595

ZT61195

ZT4795

ZT15295

ZT35695

ZT71543

ZT81642

TT080

TT1195

TT3595

TT5995

C1-67

C21495

TTM1495

TTL-67

Water: 1145 mm

Puncher : 1913 mm

TTV1920

Tin disc : 1900 mm

Rupture Wire F2 : 2316 mm

Trigger : 0 mm

SN

MS2010

X-ray845

CF-230

ZT101904

ZT91896

C31915

TTH1915

ZT1195

ZT3595

ZT5995

Dynamic pressure transducers

Sacrificial thermocouples

Lateral thermocouples

Pressure transducers

Optical mesurements

Water level transducer

Force sensor

Mass spectrometer

755

KROTOS KS3 - KS4

: 10 cm PF le 31/08/2010

K0-50

K2395

K1195

K3595

K4795

K5995

K61195

ZT2395

PyJ1637

Vidéo1595

ZT61195

ZT4795

ZT15295

ZT35695

ZT71543

ZT81642

TT080

TT1195

TT3595

TT5995

C1-67

C21495

TTM1495

TTL-67

Water: 1145 mm

Puncher : 1913 mm

TTV1920

Tin disc : 1900 mm

Rupture Wire F2 : 2316 mm

Trigger : 0 mm

SN

MS2010

X-ray845

CF-230

ZT101904

ZT91896

C31915

TTH1915

ZT1195

ZT3595

ZT5995

Dynamic pressure transducers

Sacrificial thermocouples

Lateral thermocouples

Pressure transducers

Optical mesurements

Water level transducer

Force sensor

Mass spectrometer

KROTOS: test section instrumentation

Status of the SERENA Project - Experimental tools (1)



KROTOS : X-Ray radioscopy: fine characterization of premixing

Quantitative data

O

392 878

248

200

368

14°

1

2

3

4

5

6

78

Characteristics: Source: 6-11MeV - 0.33Gy/s

Exposure: 4.5 sResolution: 240x320Color depth: grey 12 bit

Fps: 55Duration: 1650 frames (20 sec)

Corium 3D Void 3D

Corium volumeCorium surface area

Void volumeVoid surface area



Rayleigh-Taylor instability formation and stripping

Premixing and droplet formation

mechanism

KROTOS : X-Ray radioscopy: fine characterization of premixing


Status of the SERENA Project - Experimental tool (4)

KROTOS: post-test characterization of corium exploded and non exploded debris


Status of the SERENA Project - Experimental Outcomes (1)

TS and KS-4: inverse material effect: strongest explosion for composition with solidification

intervalKS and TS4: strongest

explosion never observed with protoypical materials

•FCI and material effects Before SERENA : After SERENA•Pure compound (alumina, corium azeotrope)=>Strong steam explosion

•Corium composition with solidification interval=>Weak steam explosion

•FCI and material effects Before SERENA: After SERENA:KS-5 and TS-5 weak explosion

•Oxidation effect: different reaction according to the nature of the material (oxide/”metallic”)•Simulant material #prototypical material=> impact on strength of the steam explosion


One of objectives : To reduce the scatter of the predictions in order to be able to put safety margins to containment failure

Have completed data base on the key phenomena for codes

Have provided more accurate experimental data Melt front location Mixing information jet break-up length (Krotos X-Ray system) Melt temperature Volume average void fraction Dynamic pressure and load

Status of the SERENA Project- Experimental Outcomes (2)


Status of the SERENA Project-Analytical Program (1)

The main tasks of the Analytical Working Group (AWG) are: Performing pre- and post-test calculations in

support of test specification and analysis. Improving analytical models and understanding

of those key phenomena that are believed to have a major influence on the FCI process.

Addressing the scaling effect and application to the reactor case.

Demonstrating the progress made in SERENA Phase-2 as compared with Phase-1 (in particular on reducing the scatter of the predictions) by repeating the “ex-vessel reactor exercise”.



Applied FCI computer codes and organizations using them:

MC3D ; AECL, CEA+Tractebel, IKE, IRSN, JSI, KAERI, KINS, VTT.

TEXAS-V ; UWM, VTT. JASMINE ; JNES. JEMI (IKEMIX/IKEJET) + IDEMO ; IKE TRACER-II ; KMU Codes JEMI+IDEMO and MC3D are being

ongoing improved based on AWG findings



Calculation of Experiments Performed pre- and post-test calculations

with accompanying sensitivity studies for performed experiments. Pre-test calculations for defining optimal test

conditions. Post-test calculations and sensitivity studies for

code validation, modeling improvements and as support for interpretation of experiments.

The observed differences of the simulation results between the codes and different modeling approaches, and the differences between the simulation results and experimental measurements have been analyzed and discussed.



Calculation of Experiments Performed pre- and post-test calculations

with accompanying sensitivity studies for performed experiments;The calculations are focusing on the

understanding and modeling of key phenomena influencing FCI, with reactor applications in mind.

Post-test calculations of last experiments are underway.



Reactor Case PWR: Bottom (2D) and Side Vessel Failure (3D) BWR: Bottom Vessel Failure (2D)

PWR (Bottom Failure)BWR (Bottom Failure)



Reactor Case : Representative Initial conditions



Reactor Exercise : Time Schedule June – October 2011: Calculations performed by AWG

members according to Reactor exercise specifications End of October 2011: Calculation results provided to

CEA coordinator November – December 2011: Preparation of draft

synthesis of calculations End of December 2011: Draft synthesis of

calculations submitted to Partners January – February 2012: Iteration of Draft synthesis March 2012: Final synthesis report submitted to

partners



AWG Outcome document Reflects the elaboration process and

progress in the specific tasks, focusing on key phenomena influencing the FCI, with reactor applications in mind.Jet-breakup, Melt mass and void in

mixture, Melt solidification, Explosion phase, FCI modeling in integral codes.


Concluding Remarks (1)

Steam explosion is one of major unresolved issues in severe accidents after TMI-2.

TROI and KROTOS FCI tests: new accurate data and observation thanks to experimental tests using prototypical compositions

Experimental specific features and advanced measurement techniques on KROTOS and TROI facilities

Analyses of the full experimental results must be achieved in the next 6 months

The calculations are focusing on the understanding and modeling of key phenomena influencing FCI, with reactor applications in mind.

Application to reactor case to evaluate and decrease the scatter of results


Concluding Remarks (2)

OECD/NEA SERENA project A concluding seminar will be organised on 13-

15 Nov. 2012

Thank you for your attention


TS Plan (Actual) Features

1 Challenging conditions 0.4 MPa, 301K, Mat 1: 70%UO2-30%ZrO2 (73.4:26.6 )Trigger : ~0.85 s

S/EMax. C MPa

2 Geometry effect Effect of geometry by comparison between KROTOS and TROI

0.2 MPa, 334KMat 1: 70%UO2-30%ZrO2 ( 68:32)Trigger : ~0.85 sec

S/EMax. D2 Mpa

3 Reproducibility tests 0.2 MPa, 331KMat 1: 70%UO2-30%ZrO2 ( 71:29), Trigger : ~0.85 sec

S/EMax. D1 Mpa

4 Material effectOxidic composition

0.2 MPa, 333KMat 2: 80%UO2-20%ZrO ( 81:19 ), Trigger:~1.05 s

S/EMax. B Mpa

5 Material effect Oxidation/composition

0.2 MPa, 337KMat 3: 70%UO2-15%ZrO2 + 15%Zr

Steam Spike

6 Material effectLarge solidus/liquidus T

0.2 MPa, 338K, Mat 4: 70%UO2-30%ZrO2 +FP+iron oxide; 73. : 20.4 : 4.1 : 1.3 0.3 :0.8 :0.2 8.5 (UO2 : ZrO2 : Fe2O3 : Cr2O3: BaO:La2O3:SrO) 73.32: 18.45 : 4.885 : 1.74 : 0.385 : 0.975 : 0.24 ; Trigger : ~1.05s

S/EMax A Mpa

Status of the SERENA Project- Experimental Program (4)

TROI facility


Status of the SERENA Project - Experimental Program (7)

KROTOS (Actual) Features0 KF-C

Calibration test0.4 MPa, 302K, Tmelt=2930K, free fall: 0.570mMat 1: 70%UO2-30%ZrO2

S/E

1 KS-1Challenging conditions

0.4 MPa, 302K, Tmelt=2970K, free fall: 0.570mMat 1: 70%UO2-30%ZrO2

S/E

2 KS-2Geometry effect


S/E

3 KS-3Reproducibility tests


No S/E

4 KS-4Material effectOxidic composition


S/EMax. value for SE

5 KS-5Material effect Oxidation/composition

0.2 MPa, 337K, Tmelt=2970K, free fall: 0.492mMat 3: 70%UO2-15%ZrO2 + 15%Zr

“Explosion”

KROTOS facility

ERMSAR 2012, Cologne, Germany, March 21 – 23, 2012

Background

Investigation of accident scenarios from core degradation to melt formation and relocation in the vessel, melt dispersion to the reactor cavity, MCCI and hydrogen related phenomena in severe accidents

The phenomena addressed in the studies are extremely complex and generally demand the development of specific research

The research field is too wide to allow investigation of all phenomena by any national programme

Existing experimental platforms should be opened for the transnational access to optimise the use of the resources at both national and international levels

29


Acknowledgements

The authors gratefully acknowledge funding by Euratom and CAEA to support the work within ALISA project

30


… and finally

Thank you for your attention!

31

Documents

ERMSAR 2012, Cologne March 21 – 23, 2012 Pascal PILUSO (CEA) Seong-Wan HONG (KAERI) Matjaz LESKOVAR (JSI) Presentation by François BOUSSARD (CEA) On behalf