Summary of 14th Chief Nuclear Officer Conference
1. Date:May 18, 2022 (Wed.) 10:00 ~ 12:00

2. Place:

Otemachi Headquarter, Central Research Institute of Electric Power
Industry (CRIEPI), and Webex

3. Participants:
Chair: Apostolakis (NRRC)
Members: Funane (Hokkaido EPCO),
Abe (Tohoku EPCO; substitute for Kato),
Fukuda (TEPCO HD), Ihara (Chubu EPCO),
Fukumura (Hokuriku EPCO; substitute for Ishiguro),
Matsumura (Kansai EPCO), Kitano (Chugoku EPCO),
Yamada (Shikoku EPCO),
Honda (Kyushu EPCO; substitute for Toyoshima),
Miyoshi (JAPC; substitute for Kenda),
Ota (JNFL; substitute for Matsuda),
Hagiwara (J-Power; substitute for Urashima), Asaoka (NRRC)
Observer: Nakaguma (FEPC), Hashimoto (JANSI; substitute for Yaegashi),Uozumi (ATENA), Meserve (NRRC)
Organizer: Furuta (NRRC)
NRRC Management: Yoshida, Yoneda, Iwashima, Sakuramoto, Nishi,
Matsuyama
4. Proceedings:(1）R&D Research Results of FY2021
NRRC presented the R&D results of FY2021.
(2）Activities of NRRC
NRRC reported on the Overview of NRRC’s activities
Main comments from committee members:・The development of PRA requires much cost and human resource development.
However, the cost can be soon offset if the capacity factor increases. Just as PRA
has been used in the U.S. to improve safety and maintain a high utilization rate of95%. I hope that ATENA, working with the NRRC, will revise LCOs and develop an
OLM guide using PRA and that the restarted power plants take the lead inachieving RIDM results.
・Since the initial cost of risk-informed application is high, it is important that thewhole industry recognizes the future benefits and works toward them. We needsuccessful examples such as revising LCOs and AOTs or OLM whose benefits are1

very easy to understand.
・ATENA has a deep interest in RIDM. The issue is how to get involved in this areaand how to exercise leadership in negotiating with the NRA. We would like tocontinue discussions with the NRRC and the utilities on this point.
・Spreading the use of the risk-informed application to all the utilities is a matter ofculture change within them. There is still a large gap in awareness between
personnel involved in safety and those in O&M. In addition, no matter howseriously we make proposals to the NRA, if they do not accept that, the progress
will be slow.
・Since Japanese society has difficulty in accepting risk sense, the utilities and theNRA need to work together to present risk information utilization to the society inan easy-to-understand manner. It is important to be able to explain with risk
information that more effective regulatory requirements should be implemented.
・ For the future realization of RIDM, PRA needs to be explained in aneasy-to-understand manner both within the utilities and to the public. PRA shouldbe able to demonstrate the safety improvement achieved through the addition ofspecific safety facilities and SA equipment. It can also be used for voluntary safety
improvements. In this way, we can communicate how the PRA can be utilized for
RIDM.
Main remarks from Executive Advisor:
・PRA is very valuable in that it can be used as a framework for discussion not only
among CNOs but also with the NRA. It can be used as a means of discussing, forexample, what is important or not important, what is or is not a violation ofregulations, and how effective are new or existing regulatory requirements.
・As an international advisor to the NRA, I have discussed this issue with Dr. Fuketaand Dr. Yamanaka, the previous and the present NRA chairpersons, and they both
agree on the basic idea of considering what is important and what is not important
through risk-informed regulation in the future. They are also very interested inwhat is being done internationally, so the IAEA movement and IRRS could be avery important force.
Main remarks from Director:
・ PRA is resource-intensive but pays in the long run because risk-informed
decision-making with PRA improves nuclear safety and reduces costs in nuclear
power plants.
・I believe that the cooperation with ATENA is progressing well. Since ATENA is
supposed to dialogue with the NRA, we would like to continue to work closely withATENA.
・It will take much time to apply RIDM to actual plants because a change in theculture of power plant personnel is necessary to shift from the conventional
deterministic approach to a probabilistic approach. CNO leadership in actively
implementing RIDM is very important. It is also necessary to send the same2

message to the regulatory side.
・Some NRA staff and utility employees may resist the use of risk information, which
is because it requires cultural change, but this will be overcome by gradually
accumulating the experience of its applications. In addition, we can expect
influence from overseas, just as the repeated recommendations in the IAEA's IRRS
led to the NRA's introduction of ROP.
・What the utilities should do for the public and society is to win their trust. The
public is not interested in the results of PRA and disclosing them will not lead towinning their trust. The numbers and terminology used in PRA should be used only
within the industry and in discussions with the NRA.

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