Summary of the 8th Technical Advisory Committee (TAC) Meeting
Date:
Place:

Nov. 6 – 10, 2017
Nuclear Risk Research Center (NRRC), Central ResearchInstitute of Electric Power Industry

Participants:
TAC:
Mr. Stetkar (Chair), Mr. Afzali, Dr. Chokshi, Mr. Miraucourt,
Prof. Takada, Prof. Yamaguchi
NRRC:
Dr. Apostolakis (Head), Experts of the Nuclear Risk ResearchCenterIndustry:
Experts of TEPCO Holdings, TEPCO SYSTEMS, Shikoku
EPCO for respective topics
Proceedings
All the topics were discussed in full committee. In addition, a discussion
session took place following Mr. Miraucourt’s lecture on the current practiceof risk management in France.
Nov. 6 (Mon.)
Topic 1: Risk-Informed Decision Making (RIDM) Promotion Team Activities
and Pilot Projects
 NRRC presented the current status of the activities of the RIDM
Promotion Team and the draft proposal of “Strategic Plan forImplementation of Risk-Informed Decision Making Process”.
 TEPCO Holdings and TEPCO SYSTEMS presented the current status of
the Kashiwazaki-Kariwa (KK) 6/7 pilot project. Shikoku EPCO
presented the current status of the Ikata 3 pilot project.
 TAC members commented as follows:- The information about the expert review reports and the responses tothem by the pilot projects will enable the TAC members tounderstand the quality of the risk assessment and the level of thereview. On that basis, we can make comments and write a letter fromthe technical point of view.
- Enhancement of a PRA model and data will cause some changes in
the risk profile. Then it is important that the utilities explain thereason why the risk profile has changed.

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（Handouts）
1-1. RIDM Promotion Team Activity Roadmap
1-2. Strategic Plan for Implementation of Risk-Informed Decision Making
Process
1-3. #8 TAC materials 「Ikata Unit3 Project Status Update」
1-4. KK-7 Project Internal Event Operating Level 1 PRA Model Sophistication
Progress ReportNov. 7 (Tue.)
Topic 2: Risk Assessment Research NRRC presented the general overview of NRRC’s Research Plan for FY
2018.
 NRRC presented the R&D roadmap of Risk Assessment Research for FY
2018. NRRC also presented the current R&D status of “Fire PRA Guide”
and “Multi-unit PRA”.
 TAC members commented as follows:- It is not apparent why so much time is needed to develop guidance forcommon cause failure (CCF) parameter estimation and use in PRAmodels. Substantial guidance is available and has been used in theU.S. and other countries.
- It is appropriate that you consider the implementation of Level 3
PRA at a pilot plant. We recommend that the evaluation viewpointshould not be limited to fatality but be broadened in different
perspectives.
- You should refer to the report of the SOARCA project of US-NRC,
including the project at Sequoyah nuclear plant, as thestate-of-the-art for integrating Level 2 and Level 3 PRA models,
including uncertainties.
- The overall task flow of the Fire PRA guide should clarify theinterdependency and iteration processes among tasks.
- The HRA guidance in the Fire PRA guide should be consistent with
the NRRC HRA methodology and guidance.
- Multi-Unit PRA should cover Level 2 PRA because the effect offission product release from one unit to the other units should beconsidered in the assessment. However, implementing Level 1
dual-unit PRA is a good starting point.
- Various combinations of possible seismic-induced initiating events2between multiple units should be considered.
(Handouts)
2-1. NRRC’s Research Plan for FY2018
2-2. R&D plan for FY 2018 -Risk Assessment Research2-3. Development of the Fire PRA Guide
2-4. Fire PRA Guide Chapter 1, 2, Appendix
2-5. Study on MUPRA
Nov. 8 (Wed.)
Topic 3: External Natural Event Research NRRC presented the R&D roadmap of External Natural Event Researchfor FY 2018. NRRC also presented the current R&D status of “Tsunami
PRA” and “ Status of Ikata SSHAC”.
 TAC members commented as follows:- You should plan research on natural external events while having in
mind its role in the PRA. Research priorities should integrate anunderstanding of hazard frequency and severity, building andequipment fragilities, and plant systems analysis.
- The technical integration team should play a more leading role indeveloping a process of evaluation models in both seismic source
characterization and ground motion characterization of the Ikata
SSHAC project.
（Handouts）
3-1. R&D plan for FY 2018 -External Natural Event Research3-2. PTHA (Probabilistic Tsunami Hazard Assessment) and TFA (Tsunami
Fragility Assessment) in Tsunami PRA
3-3. Technical Issues to be studied in Ikata SSHAC Level 3 ProjectNov. 9 (Thu.)
Topic 4: Discussion on French experience in risk management
 A discussion session took place following Mr. Miraucourt’s lecture on“Current Practice of risk management in France”.
(Handouts)
4-1. Current Practice of risk management in France (Mr. Miraucourt)

3Topic 5: Exit Meeting
TAC and NRRC had a discussion on how to organize future meetings. They
also discussed the “Strategic Plan for Implementation of Risk-Informed
Decision Making Process”.
Nov. 10 (Fri.)
Committee internal meeting.

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