France EDF Areva

IAEA General Conference - September 2012 - Industry Forum 1

Enhanced NPPs Safety and Protectionafter Fukushima

French Industry experience: a responsible approach

EDF / Areva

Michel Debes - EDF Generation and Engineering Division ([email protected])Bertrand Delepinois - Areva ([email protected])

IAEA General Conference 2012

Nuclear Operating Organizations cooperation Forum Strengthening the effectiveness of operating organizations

Tuesday, 18 September 2012


CONTENT

- The industry prime responsibility of safety

- Importance of periodic safety reassessments

- Avoid environment contamination, even in extreme situations

- Results of EDF Stress Tests and improvements for existing NPPs

- The EPR safety at the light of Fukushima

- Main lessons drawn for nuclear development and new projects

- Enhancing collective international safety responsibility


58 Pressurized Water Reactors (PWR) on 19 sites: 63 GW

Three standardized series: => a major safety and economic benefit � 900 MW: 34 units, 31 GW� 1300 MW: 20 units, 26 GW�1500 MW (N4): 4 units, 6 GW

Operational experience � safety and transparency as a major priority� average operation time: 26 years (10 to 34 years)� Experience feedback: ~ 1500 reactor years�Periodic 10 years Safety Reassessment process ==> Long term operation: goal up to 60 years

EPR under construction: Flamanville 3

Decommissioning program : 9 reactors (6 GGR, HWGCR Brennilis, SFR Creys Malville, PWR Chooz A)

EDF Nuclear plants in France and Operational Experi ence

Rythme de construction du parc nucléaire actuel d’E DF

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Rythme de construction du parc nucléaire actuel d’E DF

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Gravelines

Chooz

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Fessenheim

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St A lban

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Pen lyPaluelFlam anville

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BellevilleChinon

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Nogent Seine

Nuclear generation (2011): 421,1 TWh (+3,2%)kd : average 80,7% (top10: 89 to 98%) ; ku : 94,3% (frequency control, load follow..)


Safety is a prime responsibility of industry

EU Safety Directive – Art 6:

... the prime responsibility for nuclear safety of a nuclear installation rests with the licenceholder. This responsibility cannot be delegated. (cf also IAEA Safety Fundamental 1)⇒ Competences, training, procedures, design, safety culture, organisation, controls,…

… requires licence holders, under the supervision of the competent regulatory authority, to regularly assess and verify, and continuously impro ve, as far as reasonably achievable, the nuclear safety of their nuclear installations in a systematic and verifiable manner....

After Fukushima, the nuclear industry collectively shares the senseof a burning priority to be put on nuclear safety, in all circumstances


Periodic safety reassessments are key

Every 10 years : safety reassessment for each plant- reassessment of the licensing basis,

- experience feedback,

- new knowledge or evolutions,

- internal/external event: earthquake, flooding, electrical supplies, cooling water, industrial environment...

- severe accidents prevention and limitation of consequences

- probabilistic studies, backfitting (cost / benefit analysis),

- compliance assessment and checking , ageing assessment, R&D

=> as a result, a new safety basis and an improvement pr ogramme is proposed to

ASN, including safety controls and a consistent set o f modifications

• Plants built for decades must get regular design im provements

•Necessity for the operator to remain continuously i nvolved in engineering issues

• Need for an organization encompassing adequate engine ering and operational skills


Beyond design situations must be addressed

Fukushima stresses the need for a reinforced and sh ared objective worldwide :nuclear plants must be able to face extreme, beyond de sign, situations.

Objective : prevent a severe accident or, should it occ ur, avoid long term contamination.(design objective for new reactors, to be addressed f or existing plant through PSR)

► Ensure robustness and margins against extreme natural haz ards

� Earthquakes, flooding, weather…� Beyond referential (the referential remaining the referential…)

► Strengthen plant autonomy (water, power, fuel…) to co pe with :

� Long term loss of offsite power� Loss of heat sink� Devastation of roads and infrastructures around the site

► Harden the vital safety systems

► Put in place mobile means

► Ensure containment integrity in case of extreme hazards and severe accident


Results of "Stress tests" for French NPPs :- Complementary Safety Assessments- Improvements for existing NPPs and

emergency planning

Main objective

- The future NPPs have to be designed and operated with the objective that no accidental scenario may lead to long term contamination in neighbouringterritories. - This objective should be used for existing plants, underlining the importance of Periodic Safety Review process (PSR)


1/ In-depth assessment of the current safety layers according to the current design basis of:

– Physical protections such as dikes, embankments, anchorage, water resources,…

– Design Basis accident management– All relevant systems used for the safety demonstration

=> confirmation of adequate margins for all NPPs

2/ New analysis going beyond the current design bas is referential:– Efficiency of protections– Consideration of extreme situations– « Hard core » of systems and equipment enabling to avoid releases with significant long term consequences

=> If necessary, implementation of supplementary me ans– Equipment– Human resources – Local/national organization

Copyright EDF April 2012

The CSA : a two steps methodology5 technical areas to be assessed: earthquake, flooding, loss of heat sink, loss of el ectrical power, Severe accident management+ conditions for subcontracting activities (safet y, radiological protection)


The next key stepsDefinition of the industrial modification programme submitted to ASN (June 2012):

- Over 500 actions identified (ECS, GP review, etc.)

- Short-term modifications: FARN, temporary mobile equipment (small diesel generators, thermal motor-driven pumps, etc.), “plug and play” connections

- Medium-term modifications: ultimate back-up diesel (DUS), ultimate heat sink, local emergency centre, anticipation of changes in operating reference safety standards: earthquake, flooding, loss of power supply, etc.

- Long-term modifications: close interaction with Long Term Operation safety objectives and related modifications


Improvements for existing NPPs•••• Enhancing robustness of systems designed to protect key safety functions

against external hazards (earthquakes, flooding...)- flooding: protection of equipment and materials (dams or dykes, building leaktightness...) - Supplementary protection of electrical switchyards against flooding- robustness against seism: reinforcement of supports and anchorages, electrical equipment..

•••• Increasing water make-up and electrical power supply capacity, to cool the reactor and avoid fuel uncovery(reactor core, spent fuel pool)

- additional water reserve (basin, underground table…) - reinforcement of the back up cooling water supply (tank...)- implementation of additional back up diesel generator s on each unit: supply of AFW pumps, water make-up to RCS and spent fuel pool, thermal pump to supply water in RCS

- spent fuel pool operation: instrumentation (level, temperature), supply systems, fuel handling..

•••• Protective measures in case of core meltdown, minimizing radioactive releases to avoid significant long-term contamination of surrounding areas

- robustness and efficiency of U5 containment filter to limit external releases (cesium...), seismic resistance, improvement of fitration capabilities (iodine),

- soda in reactor building sumps (to trap iodine)- studies of countermeasures to avoid contamination of the water table (in case of basement melt through)

•••• Reinforcing site and national emergency preparedness organizations: - personnel and equipment; event involving multi-units on site


Key additional measures•••• Implementation of a “Hardened safety core” of systems, structures and components designed to prevent large radioactive releases to the environment in extreme conditions- protected against extreme external hazards exceeding the scope of the current design basis., - to increase mitigation and robustness beyond design ex: DUS, U5, relevant instrumentation, water make up means with dedicatedpumps, water reserve ...

•••• Nuclear Rapid Response Force (FARN)- The setting up a supplementary "resilient" line of defense through a national "Rapid Action Force" (FARN) ready to support a site in trouble within 24h (event involving multi-units ), to maintain or restore core cooling and to avoid any significant release: support team, mobile means (pumps, power, plug and play connections,...), accident management, logistics , - reinforcement of crisis management premises on site


Nuclear Rapid -Response ForceObjectives: to re-establish and/or maintain reactor cooling

with the aim of avoiding any core fusion or any significant release

Missions:


The EPR reactor safety inthe light of Fukushima


EPR Genesis

Three Miles Island (1979): Core meltdown accident

Chernobyl (1986): Dispersal of radioactive material

9/11 (2001): Terrorist attack using a commercial aircraft

• Modifications on operating plants ( human factor , severe accidents)

• Considerable R&D on severe accidents

Eliminate the risk of experiencing consequences on populationssimilar to the Chernobyl disaster (incl long term consequences)

Ensure that a terrorist attack will not cause a severe accident in the context of nuclear technology diffusion worldw ide

Operating experience• 30 years of experience of French and German fleets

• Probabilistic Safety Assessment of current plants

The EPR design includes, from its origin, all safety p rogresses.Voluntary choice of an evolutionnary design, for safet y reasons

IAEA General Conference - September 2012 - Industry Forum 15Convention SFEN – 8 et 9 mars 2012 – Analyse sûreté de l’EPR

EPR safety objectives

� Reduce core damage frequency by a factor 10

� Reduce radiological releases in case of an accident

� design basis accidents : no protection measures for the population

� practical elimination of all situation leading to larg e and early releases

(hydrogen explosion, core melt under pressure, steam expl osions)

� in case of a low pressure core-melt, only limited prot ection measures can be tolerated(eg no permanent relocation)

� Increase robustness against terrorist attacks( resist lo a large commercial aircraft crash)

� Simplify operation

� Deterministic approach, complemented by probabilistic assessment

15

• Severe accident mitigation is included in the design

• These objectives define the Gen 3 (or 3+) reactors


EPR resistance to external hazards

Margin assessment demonstrate with a high level of confidence that a Fukushima quake would not have imp acted EPR capabilities to avoid a severe accident

Buildings, would have resisted dynamic impact of the wave and a 3-4 m of flooding without risk of excessive lea ks

►Strong resistance to earthquakes

� single basemat shared by reactor, spent fuel and safeguard buildings

� all safety and support systems are seismic classified

►Protection against malvolant action

� aircraft protection shell� buildings and doors are explosion resistant

� geographical separation

►Watertight buildings and doors

1,8 m


Robustness of cooling capabilityEmergency power

6 emergency diesels plus batteries: redundant, dive rsified and protected

2 buildings located on each side of the reactor building

� impossible for both of them to be damaged by an external hazard (explosion, airplane crash…)

Physical separationPhysical separation

4 main 100% redundant diesels: 72 hours autonomy each, at full load

2 additional SBO diesels : fully diversified, 24 hours autonomy each

batteries: 12h autonomy

DieselsSBO

Physical protectionPhysical protection

Diesels & fuel tanks housed in reinforced buildings

� earthquake resistant

� doors designed to resist explosions & floods

Redundancy & diversificationRedundancy & diversification


1

2

3 4

4 safety trains located in 4 dedicated safeguard buildings2 safeguard buildings are further protected by the APC shellOne train is enough to cool the core(“100% train”)

Highly redundant cooling systems, with two ways to cool down the core in accident conditions

Tanks(4x

400m3)

Cooling through secondary loop with EFWS1

Cooling through primary loop with safety injection system

Pressurizer

IRWST2 (1800 m3)

For each train:2 redundantand diversesub-systems

Four 100% safety trainsFour 100% safety trains

2. Safety injection system2. Safety injection system

1. Emergency feedwater system1. Emergency feedwater system

Robustness of cooling capabilityRedundancy & diversity


Robustness of cooling capabilityWater supply

In case of loss of main heat sink access ,the EPR™ reactor can rely:► On an alternate heat sink source 1 (against floods or earthquakes…)► On significant protected water reserves:

► four EFWS2 tanks in the safeguards buildings► a large fire fighting tank ► the IRWST3 in the reactor building

1

2

3

Pump

Emergencyinjection system(water reserve in reactor building)

Fire fightingTank

(2600m3)

Pump

4 Tanks400m3

x4

Heat sink(e.g. ocean)

IRWST (1800m3)

Alternateheat sink

Emergencyfeedwater system(water reserve in

safeguard building)

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5

3

4

5

The EPR™ design has multiple and diverse access to wat er


Severe accident mitigation

Elimination of H2 riskElimination of H2 riskPrevention of high pressure core meltPrevention of high pressure core melt

Short and long term function of containment ensuredShort and long term function of containment ensured Prevention of direct leakagePrevention of direct leakage

Minimize H2 concentration :� Large reactor building with

interlinked compartmentsReduce H2 quantity:

� Passive Autocatalytic Recombiners

Core melting at high system pressure can potentially lead to loss of containment integrity and major melt dispersalThe EPR™ design includes additional dedicated primary depressurization valves

Reinforced containment

Core catcher

Long term cooling (severe accident

dedicated system)

► Basemat integrity ensured

Potential containment leakage is collected in the annulus (sub-atmospheric pressure)


Post-Fukushima Safety authoritiesassessments on EPR ™ Design

Stress tests performed in Europe highlighted the intrin sic robustness of the EPR design:

� France : ASN reported that “the enhanced design of [the EPR ensures already an improved robustness with respect to the severe accident”

� Finland : STUK highlighted that “earthquakes and flooding are included in the design to ensure safety functions to a high level of confidence

� UK : ONR issued the EPR interim Design Acceptance in December ’11, stating that there is no ‘show stopper’ regarding EPR™ safety


EPR synthesis►EPR safety principles are conforted after Fukushima :

� robustness towards external hazards

� enhanced defence in depth

� severe accident mitigation included in the design

► modifications will be made to further strengthen safet y :

� reinforced water tightness

� longer autonomy (diesel fuel, batteries)

� connections for mobile means

► the lesson learnt process will continue


Lessons drawn

for New projects


Key Success Factors for Nuclear Development

•••• Developing a nuclear program involves a wide range of initiatives:

- Setting the proper regulatory framework

- Establishing optimal industrial organisation for new nuclear plant construction

- Selecting a technology

- Building a solid, secure plan for the entire nuclear fuel cycle (front end, back end, waste management...)

- Setting up an efficient operation system

- Training, boosting national expertise

- Involving local suppliers in the programme (qualification, oversight...)


► The strengthening of safety requirements :

� Generation III and III+ reactors to be the reference

� in Europe Gen 3+ are defined by the WENRA safety objectives for new reactors

� WENRA and IAEA SSR 2-1 standards seem valid after Fukushima

� some adjustments may be made, according to the full return of experience

� actual implementation is the major stake

► The independence of the regulator : a key factor

► International institutions’ greater role (IAEA, OECD /NEA etc.) in the development of new nuclear power programs (forwarding high safety standards)

►Role of WANO to enhance operator's responsibilities at international level.

Fukushima impact on New Nuclear Build

Nuclear safety involves a collective responsibility and action


Thank you

for your attention

and your questions …

Documents

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