www.cea.fr www.cea.fr

NUCLEAR SAFETY &

SEISMIC RISK MANAGEMENT IN

FRANCE: OVERVIEW

SEPTEMBER 28, 2016, SCIENTIFIC & TECHNICAL SEMINAR AT THE

CANADIAN NUCLEAR SAFETY COMMISSION

| Catherine BERGE-THIERRY,

Seismologist & Seismic Risk Expert at CEA

21 OCTOBRE 2016 | PAGE 1 CEA | 10 AVRIL 2012

CONTENT

1. Introduction

2. French Approach to define the seismic hazard for nuclear

facilities

3. French Approach and acceptance criteria for the design and

assessment of nuclear facilities

4. Seismic risk management in light of Fukushima action items

5. The SINAPS@ research project

6. Conclusions et Discussions

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CONCLUSIONS

21 OCTOBRE 2016

| PAGE 3

CEA | 10 AVRIL 2012

This presentation gave an overview of the current practices used in France to assess

seismic hazard in the field of nuclear safety:

French regulatory body (guides & rules) fully DSHA,

Post-Fukushima & CSS required to complete with PSHA,

Current RFS (updated in 2001) approach :

doesn’t describe clearly/enough how managing uncertainties, neither which

level of hazard is expected (best-estimate ? “most penalizing” ? ) : even if

safety coefficients are included, expert’s debates strongly dominate the NP’s

safety reports instructions;

for example, need to improve the site specific approach (“generic Vs30m”

through classes versus real measured on site velocities), the ground motions

prediction …

Implementation of PSHA in the frame of NP’s safety is recent in France (2012) and first

studies performed in the CSS framework conduct (again/already) strong expert’s

debates. ASN finally is able or not to rule the “right” seismic level to account for.

Whatever the approach DSHA-PSHA used :

data and metadata are the same, as uncertainties characterizations,

models and assumptions differ

target level has to be precised:

SSE / PaleoEQ … (Mmax ?)

Tr=20 000y for CSS - Hard Core Level, but which level of confidence ?

CONCLUSIONS

This presentation also gave an overview of the current practices used in France to

design structures against earthquake, and presented the French safety analysis bases,

safety objectives, criteria and recommended methods (Guide ASN/2/01)

We saw several of retrofits, & seismic isolation technique

Specific difficulties associated to the seismic assessment of existing NP’s

No time but should be really interesting to talk about :

the coherency between the S.H.A. outputs and the engineers needs,

how to select/choose time series compatible with hazard – DSHA –

PSHA ?

on the identification/ propagation of uncertainties throughout the

whole seismic risk analysis …

Regulation/Practices versus knowledge evolution: gap between R&D improvements

and the updating of regulations (need of return experience) : this situation strongly

complicates safety reviews.

Seismic Margins Assessment reliable only if whole (complete & continuous approach

including uncertainties propagation) seismic risk analysis is performed.

CONCLUSIONS

NEED OF UPDATING REGULATIONS VS KNOWLEDGE

IMPROVMENT

6

RFS I.2.c

2000 – Expert’sGroup

• Active Faults,

• PaleoEQ

• Past Earthquakes characterization,

• Magnitude assessment,

• Strong motion prediction,

• Site Effects (Mexico - 1985, Loma-Prieta -

1989, Northridge - 1994, Kobe - 1995 …)

RFS 2001-01

Knowledge evolution … 1981

French nuclear Program ~ 1960

RFS & other guides for

seismic risk for safety

management : date from

1984 to 2006.

No soil class, No site effect , No PaleoEQ, No minimum level

2 soil classes, Site effects (1D & paritucular S.E. ?) PaleoEQ (experts #), Minimal Level

RFS I.2.c

2000 – Experts Group (French)

• Active Faults,

• PaleoEQ

• Past Earthquakes

characterization,

• Magnitude assessment,

• Strong motion prediction,

• Site Effects

RFS 2001-01

Knowledge evolution… 1981

French nuclear Program ~ 1960

Evolution des connaissances …

2017- ?

20?? – 20-?? Experts Group • Active Faults,

• PaleoEQ

• Past Earthquakes

characterization,

• Magnitude

assessment,

• Strong motion

prediction,

• Site Effects

• SSI,

• Structures &

componants

vulnerabilities,

• Uncertainties

• Risk

Experience Feedback, France

• On the RFS 2001-01 application,

• PSHA practice,

• NCOE 2007 & Tohoku 2011,

• Complementary Safety Studies

• Seismic Margin Assessment

KARISMA – IAEA 2010, SMART

2006-2013, MECOS 2016, …

• R&D Hazard, Vulnerability &

Risk;

- CASHIMA2003-2015

- SIGMA 2010-2015

- SINAPS@ 2013-2018

Identify practical & scientific

challenges

Toward regulation & references

evolution ?

Need to Explicite Uncertainties to

Quantify Margins

Experts opinions management …

… Need to a real integrated

Seismic Risk Vision

• Site-specific studies • Site characterization

Vs30m, f0, measurements…

• Site effects (empirical/numerical

• PaleoEQ versus Mmax …

• DSHA/PSHA…

International Experience Feedback, • OECD, • IAEA (TECDOCs, Safety

Guides & Reports) …

NEED OF UPDATING REGULATIONS VS KNOWLEDGE

IMPROVEMENT … INCLUDING RETURN OF EXPERIENCE

Commissariat à l’énergie atomique et aux énergies alternatives

Centre de Saclay | 91191 Gif-sur-Yvette Cedex

T. +33 (0)1 69 08 66 55

Etablissement public à caractère industriel et commercial |

RCS Paris B 775 685 019 21 OCTOBRE 2016

| PAGE 8

CEA | 10 AVRIL 2012

Catherine BERGE-THIERRY

CEA/DEN/DANS/DM2S

• Seismologist – Seismic Risk Expert Centre de Saclay

catherine.berge-thierry@cea.fr

• SINAPS@ R&D project coordinator

http://www.institut-seism.fr/en/projects/sinaps/

• SEISM Institute Scientific Director

http://www.institut-seism.fr