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transcript
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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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