Summary of the 14th Technical Advisory Committee (TAC) Meeting
Date:
Place:

July 27, 2021
Nuclear Risk Research Center (NRRC), Central Research Instituteof Electric Power Industry

Participants:
TAC:
Mr. Stetkar (Chair), Mr. Afzali, Dr. Chokshi, Mr. Miraucourt,
Prof. Takada, Prof. Yamaguchi
NRRC:
Dr. Apostolakis (Director), Experts of the Nuclear Risk ResearchCenter
Observers:
The Japanese Utilities and Vendors, Federation of Electric Power
Companies of Japan (FEPC), and Atomic Energy Association(ATENA)
Proceedings
The topics on Fire PRA Guide (FPRAG) and the trial application (Model plant PRA)
were discussed. NRRC will respond within several weeks to about 70-pages
document of Mr. Stetkar’s technical comments on the FPRAG.

Topic 1 : Road Map and Recent Major Outcomes of Fire PRA (FPRA) Research NRRC presented “Road Map and Recent Major Outcomes of FPRA Research”.
Topic 2 : Response on RIDM Application, Feedback from stakeholders, Scope, Peerreview, Walkdown NRRC presented "Response on RIDM Application, Feedback from stakeholders,
Scope, Peer review, and Walkdown.”
 TAC members commented as follows:- Although the expression “burden reduction” through the utilization of riskinformation is used in the NRRC materials, this is not the only purpose ofRIDM. One of the most important goals is not the relaxation of regulatory
requirements for safety enhancement measures through proper plant
operation and the concentration of the resources on safety-critical matters but
the optimization of them. In the United States, the parallel development of
PRA methodology and utilization of risk information caused rework andadverse effects. I would like to recommend that Japan work on the utilizationof risk information based on the lessons learned from the failure experience inthe United States.

1---Peer review is important in conducting PRA under the following conditions: (1)the Regulatory authority accepts the importance of peer review and (2) the peer
review process is trusted by the stakeholders.
The idea to develop the LPSD FPRA guide is not recommended. It is sufficient
to revise the following three points regarding the LPSD FPRA: (1) plant
response model, (2) fire ignition frequencies and (3) fire of transientcombustible materials.
Walkdown is important, and it is recommended to describe the form in theguide.

Topic 3：Estimation method of Fire Ignition Frequencies of the Japanese NPPs NRRC presented“the estimation method of fire ignition frequencies of theJapanese NPPs.”
-TAC members commented as follows:
The fire ignition frequency is very important. We will check the contents of thepresentation materials and send our comments by mid-August.

Topic 4 : Trial Application of NRRC's FPRAG to Model plant PRA
 NRRC presented "Trial Application of NRRC's FPRAG to model plant PRA.” TAC members commented as follows:- Since the Human Reliability Analysis (HRA) of Task 3 and Task 7 is important,we hope the NRRC's HRA Guide will be used in these tasks. We strongly
recommend that the NRRC's HRA team be involved in the implementation ofTasks 3 and 7.
- In implementing FPRA, the collaboration among the personnel involved increating FPRA models, implementing walkdown, and defining firecompartments is very important. Therefore, we recommend checking the areas
where detailed analysis is required in Phase B when walkdown of phase A iscarried out.

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