CONFIDENTIALRESTRICTEDPUBLIC INTERNAL

Technical Working Group on Life Management of NPPs - Vienna, 22/02/2017

PLIM and LTO activities in BelgiumFocus on Tihange 1 unit

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R.Gérard (Tractebel-ENGIE)

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Chapter 1 Introduction.

Contents

Chapter 2 LTO “ageing”

Chapter 3 LTO “design upgrade”.

Chapter 4 Belgian stress tests and post-Fukushima measures

Chapter 5 Conclusions

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Doel & Tihange NPPs (Belgium)7 PWR units operated by Electrabel (ENGIE)

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1. Doel 1 - 433 MW (1975,in LTO) 2. Doel 2 - 433 MW (1975,in LTO)3. Doel 3 - 1006 MW (1982)4. Doel 4 - 1046 MW (1985)

5. Tihange 1 - 962 MW (1975,in LTO)6. Tihange 2 - 1008 MW (1983)7. Tihange 3 - 1046 MW (1985)

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LTO in Belgium

Following Belgian Safety Authorities position, LTO implementation around 4 axes

Ageing management In depth analysis of ageing phenomenon applied to all safety related components

Preconditions Minimum requirements to be met: Mainly organization & documentation

Design upgrade Identify main safety concerns and define improvements following a risk reduction approach

Knowledge, competence and behaviour management

Evaluate and maintain the appropriate knowledge level and behaviour during the LTO period

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LTO “Ageing” for Tihange 1

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LTO Tihange 1 timeline – Study phase 2009: Publication of LTO strategic note by the Safety Authorities

2009-2011: Study phase of LTO projects and LTO reports publication (837 commitments)

June 2012: Agreement of the Safety Authorities of LTO action plan

July 2012: Government decision to extend operation of T1

December 2013: Modification of the 2003 law to allow a LTO of Tihange 1

March 2014: Agreement signed between GDF SUEZ – EDF – Belgian government

2009 2010 2011 2012 2013

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LTO - Ageing – Scope and methodologyCompliance with international standards

Ageing part of the Project has been carried out under the FANC regulation and follows the national and international standards :

‐ 10 CFR part 54 (requirements for the renewal of operating licence for NPP)‐ NUREG-1801 (Generic Aging Lessons Learned report) - NEI 95-10‐ IAEA approach (SRS-57: Safe Long Term Operation of Nuclear Power Plants)

Providing an overall and integrated approach across the areas of LTO interest in compliance with IAEA rules

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Active components = Living RCM Program and RSQ

Passive components = Application of Integrated Plant Assessment (IPA as defined in 10CFR 54.3)

Ageing

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Design upgrade for Tihange 1

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Design upgrade

Safety Concerns fall into 9 “areas for Safety improvement”— Back up safety— Earthquake — Fire— Flooding— Operator training— Physical separation— Qualification— Severe Accident— System

37 Agreed Design Upgrade – 12 Projects

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All potential improvements are ranked according to their contribution to nuclear safety improvement in order to propose to the Regulator a Design Upgrade

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Design reevaluation – Selected Safety Improvements

Enhancement of existing ultimate shutdown systems

— Objective: allow safe shutdown in extreme conditions (eartquake, flooding, fire…)

— Issue: Analysis of existing control and electrical system design weaknesses concluded that the existing back-up system should be more independent and should ensure safe cold shutdown

Scope

‐ Definition of new Design Basis and functional requirements (Fukushima lessons learned have been taken into account)

‐ Design of new Back-up system with independent control systems, control room and electrical supply‐ Design of two new safety related buildings (Electrical and Diesel Generator) including an additional

auxiliary feedwater capacity (tank and pumps)

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Enhancement of existing ultimate shutdown systems

Project duration 7 years (up to 2019)

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Installation of a Containment Filtered Venting System (CVCS)

Issue: In case of severe accident and inevitable pressure build-up in the containment, the use of a CFVS prevents the rupture of the containment, while keeping the radioactive releases as low as possible

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‐ Following Fukushima event, Safety Requirements for CFVS are increasing (high filter efficiency, consideration for organiciodine, seismic resistance, …)

‐ Installation in Tihange 1 on-going

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New full scope simulator

Operational since 03/2016

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Belgian stress tests and post-Fukushima activities

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Stress tests – The triggerFukushima, March 11th 2011 at 14h46 (JST)

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‐ Magnitude 9 Earthquake on Japan East coast

‐ Epicenter located 180 km from Fukushima Daiichi and 24 km under Pacific Ocean surface : huge tsunami waves reaching 6 reactor units

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The earthquake induced:

— Automatic scram of the reactors

— Loss of off-site power

— Automatic start of emergency diesels

The tsunami induced:- Total loss of heat sink (water intake & pumping

station)

- Total loss of emergency diesels loss of all electrical power supplies

Fukushima Daichi: accident origin

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No core cooling start of the accident

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Stress tests across Europe

Objective : reassessment of the response of the NPP when facing a set of extreme situations taking into account defense-in-depth & preventive measures

— Assessment of all European NPP’s requested by the European Commission

— Issues highlighted by the events in Fukushima: combination of initiating events

Assessment, finalized end of 2011, included:

— Earthquake, Flooding, other extreme natural conditions

— Consequential loss of safety functions (total loss of electrical power, total loss of the main ultimate heat sink)

— Accident management issues (Core melt accident, Degraded conditions in spent fuel storage)

— Additionally, in Belgium: man-made events (Toxic & explosive gases, aircraft crash, cyber-attack)

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Conclusions from the Belgian Safety Authority:“The robustness of the Belgian Power Plants is satisfactory. The reassessments performed in the wake of the Fukushima accident for Doel & Tihange units show that in all considered scenarios, the facilities are capable of maintaining their essential safety functions, either relying upon the redundant and diversified equipment and systems that were considered in the design phase or using mobile devices deployed on the sites. In some cases, extra improvements have been proposed in order to further enhance the robustness of the facilities against situations that are unlikely to occur when considering multi-units events”

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Selected safety improvements

Extra improvements have been defined to increase the robustness of the NPP’s as a result of the stress tests evaluation or in the frame of other safety projects (10 yearly safety Reassessments):

Earthquake:

— Study for the confirmation of the adequacy of the design basis earthquake

— Opportunity to strengthen & reinforce anchoring of some electrical and mechanical equipment for Doel & Tihange

Flooding:

— Need of an improvement of the Tihange site protection against flood as determined by Periodic Safety Review (10,000 years flooding event =new design basis condition for Tihange NPP site)

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Hydraulic Simulation to determine 10 000 years flooding event :

—Risk of site flooding of more than 1m

—Site flooding is a Common Cause Failure for all Original Emergency Systems

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New design basis

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Flooding TihangeA new concrete waterproof wall surrounding the site (2km long)

A 500m shock-resisting dike

An isolation structure in the intake channel equipped with motorized penstocks

Isolation chambers installed at the different NPP sewage discharges and equipped with butterfly valves

Dedicated make-up and discharge equipment and systems for Nuclear Island heat sink during the flooding period

Pumping stations to evacuate accumulated water on site during the flooding period

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Flooding Tihange

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Penstock installation in the intake channel

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BEST- Selected safety impovements

Non- conventional mobile means (diesel, pumps, flexible connexions):

- Water injection into RCS, SG’s, fuel pool

- Reactor Cavity water injection, alternative spray

- Fire truck to cope with airplane crash

- Stockage structure of mobile means

New Emergency response center (COS) - site Tihange

- Protected against extreme natural hazards

- Multi-units accidents

- 45 persons with an autonomy of 72 hours

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Conclusions

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Conclusions

3 Belgian units are now in the LTO period (operation until 50 years): Doel 1 and 2 and Tihange 1

The “Ageing” part for passive equipment was treated in accordance with the U.S. rules and methodology for the License Renewal (10 CFR part 54).

The “Ageing” part for active equipment was treated within the “Reliability Centered Maintenance” approach applied by Engie Electrabel.

In the framework of the LTO project significant design upgrades were agreed with the Safety Authorities and are being implemented.

Following the Fukushima event the “Belgian Stress Tests” led to additional safety improvement (flood protection, non conventional mobile means, new emergency response center,….).

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