Summary of the 4th Technical Advisory Committee (TAC) Meeting
Date:
Place:

Oct. 26 – 29, 2015
Central Research Institute of Electric Power Industry

Participants:
TAC:
Mr. Stetkar (Chair), Mr. Afzali, Dr. Chokshi, Mr.
Pouget-Abadie, Prof. Takada, Prof. Yamaguchi
NRRC:
Dr. Apostolakis (Head), Experts of Nuclear Risk ResearchCenterIndustry:
Representatives of Federation of Electric Power Companies(FEPC), Experts of Shikoku EPCO and Mitsubishi Heavy
Industries (MHI) for respective topics

Proceedings
All topics were discussed in full committee.
No focused sessions were held in the 4th TAC meeting.
Oct. 26 (Mon.)
Topic 1: Seismic Fragility Analysis Methodology• NRRC presented the current status of evaluation methods for seismic
fragility, slope stability analysis, and the use of earthquake experience
data.
•TAC members commented that NRRC should make a comparison
between the values used outside of Japan and those used in Japan
regarding β values, standard deviations of uncertainty in seismic fragilityevaluation.

(Handouts)
1-1. Progress of research regarding seismic fragility evaluation based on TAC
discussions
1-2. Slope and foundation ground stability/fragility analysis and R&D
1-3. Seismic Experience DataOct. 27 (Tue.)
Topic 2: Ikata Unit 3 Level 1 Full Power PRA Status Update•

Shikoku EPCO presented the latest status of Ikata Unit 3 PRA project,such as upgrading the event trees (including reviewing the selection ofinitiating events), and upgrading PRA parameters.

•TAC member commented that the Ikata Unit 3 PRA Project team ismaking excellent progress. The event trees have improved substantiallybeyond what was examined before.

(Handouts)
2-1. Ikata Unit 3 Internal Event Level 1 Full Power PRA Status Update2-2. Ikata Unit 3 Internal Event Level 1 Full Power PRA Status Update (I-2Upgrade initiating events)
2-3. Ikata Unit 3 Internal Event Level 1 Full Power PRA Status Update (IIUpgrade PRA parameters)

Topic 3: Seismic Hazard Analysis SSHAC Status Update•

NRRC presented the progress toward application of the Senior Seismic
Hazard Analysis Committee (SSHAC) methodology.

(Handouts)
3-1. Current Status of SSHAC Project

Oct. 27 (Tue.) – 28 (Wed.)
Topic 4: NRRC Research Plan (Presentation of All Research Topics)•NRRC presented its research plan which covers both risk assessment
field and external natural events field.

• TAC members made the following comments<Risk Assessment field>•

It is beneficial to refer to the US NRC task force report (SECY 15-0137)
on the feasibility of evaluating seismic-induced internal fires, which will
be released soon.

•

Interpretation and communication of the updated PRA risk results will be
an important issue.

<External natural events field>•

The results of the research on fault displacement will be useful not only
for Japanese utilities but for others in the world.

•It is important to investigate the dependence and correlation among
components in seismic fragility assessment.

•To the extent possible, modeling of natural phenomena such as tornadoes
and typhoons should account for historical data and evidence.

•With regard to volcanoes, it is reasonable to give first priority to theassessment of volcanic ash influence.

(Handouts)
4-1. FY2016 Research Plan - Risk evaluation team 4-2. R&D related to natural external events

Oct. 29 (Thu.)
Topic 5: Selected NRRC Research Topics••

NRRC presented the specific progress of the research on fire PRA andHuman Reliability Analysis.
Open discussion１) was held on multi-unit PRA methodology.
1) Open discussion: the session does not reach any conclusions. Participants
freely exchange their opinions based on their own experience and knowledge.
This type of session is introduced starting from this meeting.

(Handouts)
5-1. Fire PRA
5-2. NRRC’s HRA Upgrade5-3. Open Discussion on multi-unit PRA methodology

Topic 6: (Discussion) “State-of-the-Practice” vs. “State-of-the-Art” PRA•In the discussion on “Ikata PRA Scope and Project Plan” at the 3rd TAC
meeting, TAC and NRRC agreed that the concepts of“state-of-the-practice” and “state-of-the-art” will be discussed andclarified further at the next TAC meeting. In this meeting, TAC, NRRC,and the PRA promotion task team of FEPC discussed it in an open

discussion manner.
(Handouts)
None.

Topic 7: (Discussion) TAC Role and Responsibilities•TAC and NRRC looked back at TAC’s activities in the first year, andexchanged opinions in open discussion to have a common understandingof TAC’s role and responsibilities as TAC helps the NRRC to achieve itsmission. Further enhancements will be discussed during the 5th TAC
meeting in May 2016.

(Handouts)
7-1. TAC Role and Responsibilities