About NRRC
Organization
Activities
Activities
Workshop
- Summary of Nuclear Risk Research Center Workshop in 2024
- Risk-Informed Decision-Making: Benefits and Obstacles - - Summary of Nuclear Risk Research Center Workshop in 2019
- Improvement of Risk Management on Nuclear Power Plants-, January 2019 - NRRC Risk-Informed Decision Making Workshop Report, June 2017
Summary of the Nuclear Risk Research Center Workshop in 2024
- Risk-Informed Decision-Making: Benefits and Obstacles -
Purpose of the Workshop
The utilization of risk information has provided the world nuclear community with numerous benefits over the almost 50-year history since WASH-1400. Japan has experience in using risk information over the 30 years since Individual Plant Examination and Periodic Safety Review were required for operators. Probabilistic Risk Assessment (PRA) was highlighted in Japan anew after the Fukushima Daiichi Nuclear Power Station Accident as an effective and powerful tool to promote the safe operation of nuclear power plants through Risk-Informed Decision-Making (RIDM).
The operators developed a Strategic Plan and an Action Plan for RIDM in 2018 and revised it twice, in 2020 and last year. The NRRC supports the activities by the operators to develop a good PRA methodology and associated human resources. But, we have to admit, these efforts fall short of expectations with both the nuclear industry and the regulator in terms of safety improvement and reflection in regulations using the obtained risk information. We have to acknowledge the situation frankly and find the reasons and possible measures to resolve them.
In light of these considerations, we have organized a workshop that would allow the exchange of views on benefits from and obstacles to RIDM and the application of risk information.
In the workshop, we seek to:
Event Information
| Host | Nuclear Risk Research Center, CRIEPI |
|---|---|
| Date | November 12, Tuesday and 13, Wednesday |
| Venue | Forest Hall, Abiko Area, CRIEPI |
| Participants | About 180 (speakers and commentators:19, utility experts: about 50, Nuclear Regulation Authority experts:about 20, and the remaining vendors, general contractors, university officials, etc.) |
| Language | Japanese-English simultaneous translation |
Program
Summary
Opening Session
Dr. George Apostolakis, Director of Nuclear Risk Research Center (NRRC), introduced the workshop by explaining his thoughts on the benefits of Risk-Informed Decision-Making (RIDM) and the obstacles in Japan.
Keynote Speeches
Mr. Doug True, Senior Vice President of Technical and Regulatory Services and Chief Nuclear Officer, Nuclear Energy Institute (NEI), U.S.A., gave a speech about benefits of risk-informed decision-making in U.S. nuclear power plants, including how the implementation of risk-informed programs, such as the maintenance rule, has not only increased the availability of nuclear power plants, but also improved safety, with CDF of internal event PRA decreasing by a factor of 20 from the value in the 1990s to the present.
Next, Mr. Isaka, Nuclear Power Safety & Technology Supervisor, The Kansai Electric Power Co., Inc., gave a speech about current status of initiatives of RIDM, as well as efforts to further promote this, such as setting performance metrics at Kansai Electric Power and utilizing fire PRA, which is currently under consideration.
Dr. Taniguchi,Visiting Professor, The University of Tokyo, gave a speech about deficits in risk governance before the Fukushima Daiichi Nuclear Power Plant accident and issues to be considered for the realization of future risk governance.
Sessions for Obstacles
Session1: Ensuring Good PRA
Chaired by Mr. Sato, Director, Atomic Energy Association (ATENA), speeches were given by Mr. Kagawa, Nuclear Safety & Risk Assessment Group, Nuclear Research & Training Center, Nuclear Power Division, Shikoku Electric Power Co., Inc., Dr. Yoshida, Deputy Director of Nuclear Risk Research Center (NRRC), and Mr. Yonebayashi, Senior Engineer of ROP Assessment Oversight Planning and Coordination Division, Nuclear Regulation Authority (NRA) JAPAN. Then, the chair and speakers took the stage and a discussion took place. Such as:
- A obstacle may be a difference in the perception of the value of PRA models and data between utilities and regulator.
- Anoher obstacle may be that there is a possibility of shortage of PRA specialists on both utilities and regulators.
- Currently, the gap between Japan's PRA models and failure rate data and those of other countries has been specifically identified, and the current PRA model and domestic PRA component failure rate data have been improved to the international level.
- It is important for both utilities and regulator to increase their proficiency in PRA and develop human resources. This is also important for peer reviews conducted to ensure the quality of the PRA model.
Session2: Recognizing and Accommodating Uncertainty
Chaired by Dr. Nishimura, Associate Vice President, Nuclear Risk Research Center (NRRC), speeches were given by Dr. Matsuyama, Associate Vice President, Nuclear Risk Research Center (NRRC), Mr. Sato, Deputy General Manager, Nuclear Power Department, Nuclear Power Division, Tohoku Electric Power Co., Inc., and Mr. Murakami, Director Risk Management Office, Nuclear Regulation Authority (NRA) JAPAN. Then, the chair and speakers took the stage, and a discussion took place. Such as:
- There needs to be a common understanding that PRA does not create uncertainty and uncertainty exists even in deterministic evaluations.
- Making decisions with uncertain information requires that management and staff who actually handle the information understand this uncertainty.
- There are methods to quantitatively evaluate uncertainty. Some of the uncertainties can be evaluated by sensitivity analysis, while for those uncertainties for which sensitivity analysis is not possible, at least expert judgment is utilized.
Session3: Establishing Performance Metrics
Chaired by Dr. Yamamoto, Professor, Nagoya University, speeches were given by Mr. Narumiya, Chairperson, Risk Science and Technology Division, Atomic Energy Society of Japan, Ms. Zawalick, Vice President, Generation Business & Technical Services, Pacific Gas and Electric Company, and Mr. Ono, Senior Vice President Evaluation & Assistance, Japan Nuclear Safety Institute (JANSI). Then, the chair and speakers took the stage and a discussion took place. Such as:
- One of the obstacles may be not knowing how to communicate about RIDM due to lack of practical experience in RIDM.
- Performance metrics can only be used for limited purposes such as SDP, so it is important to make efforts to use them for a wider range of purposes.
- Safety goals and performance metrics play an important role in communication among utilities, regulator and society.
- Improving plant performance through RIDM leads to improved plant safety.
Summary of the 3 Sessions
Chaired by Dr. Yamaguchi, the panel discussion included Mr. Sato, Dr. Nishimura, Dr. Yamamoto, and Mr. Morishita, Director-General, Nuclear Regulation Authority (NRA) JAPAN, based on the discussions in each session on PRA models, uncertainties, and safety goals.
There was a discussion such as:
- It is important to promote RIDM using the best available PRA model, and when doing so, to determine the scope of application taking into account the quality of the model.
- The method of ensuring the technical adequacy of a PRA model is a peer review.
- Regarding the task of shortage of human resources, it is important to proceed one step at a time with existing resources.
- Risk increments can be evaluated quantitatively, but the risk reduction is often difficult to evaluate quantitatively.
- By promoting RIDM, it is important for both regulator and utilities to focus resources on areas that contribute to improving safety.
Closing Session
In the closing remarks, Dr. George Apostolakis expressed his gratitude to all the speakers and participants, and emphasized the importance of incorporating RIDM into regulations.
Summary of the Nuclear Risk Research Center Workshop in 2019
-Improvement of Risk Management on Nuclear Power Plants-
Purpose of the Workshop
In order to continue the safe operation of nuclear power plants, it is necessary to continuously improve the risk management processes at the utilities. The NRRC and the industry are developing technologies to support risk management following the objectives and recommended actions in the Strategic Plan and the Action Plan that were announced at the NRRC sponsored symposium in February 2018.
This time, we organized a workshop that would allow the exchange of technical views on the NRRC and utilities’ activities, between the NRRC and domestic and international experts from the industry and regulatory authorities.
Event Information
| Host | Nuclear Risk Research Center, CRIEPI, in coordination with OECD/NEA WGRISK |
|---|---|
| Date | January 29, Tuesday and 30, Wednesday, 2019 |
| Venue | Fukutake Hall, University of Tokyo |
| Participants | 189 (presenters: about 20, utility experts: about 70, Nuclear Regulation Authority experts: about 15 and Atomic Energy Society of Japan) |
| Language | Japanese-English simultaneous translation |
Program
Summary
Opening Session
After welcoming address by Dr. George Apostolakis, the Head of Nuclear Risk Research Center, Mr. William Magwood, Director General of Nuclear Energy Agency, OECD gave the opening address and asked for active discussion.
Session A: Enhancing Risk Assessment Technologies
Initiatives and tasks aimed at putting the probabilistic risk assessment (PRA) technology into practical use were introduced.
As for Level 1 PRA, the status of the improvement of PRA technology which was modeled on Shikoku Electric Power Company’s Ikata Nuclear Power Station Unit 3 as Japan's efforts were presented. Then, the status of PRA development and utilization in USA was reported, and issues in promoting PRA's improvement in Japan were discussed.
As for Level 2 PRA, the status of PRA utilization in USA and OECD/NEA member countries was reported.
After that, Japanese experts reported the guideline for Human Reliability Analysis (HRA) and the implementation guidance for fire PRA in nuclear power plant as an example of efforts to enhance PRA technology. Regarding natural external events PRAs, the Research and Development (R&D) status of earthquake and tsunami were reported by domestic and international experts. Also the development of PRA Standards in the USA was presented.
Session B; ROP (Reactor Oversight Process): An example of Risk Management
The preparations and challenges for the full-scale introduction of ROP in FY 2020 were reported from both the utilities and the regulatory authorities.
Experts with experiences of foreign utilities and regulatory authority made recommendations and suggestions to Japan.
Session C; Discussions on overall program
An academic organization’s expert gave a presentation on their support for risk management activities in nuclear industry. Finally, based on the presentations and discussions in the overall program, we conducted a general discussion with all participants with moderator the Head of NRRC, Dr. Apostolakis.
Results
In this workshop, the R&D activities of NRRC were also reported, and they were proved to be effective. NRRC also recognized that it was important to continue R&D activities on PRA in collaboration with utilities and domestic and international experts.
To operate and utilize ROP, which will be introduced in full scale in FY 2020, we have clarified what the utilities, the regulatory authorities and NRRC should work on about PRAs.
In addition, it was confirmed that the introduction of ROP makes it possible for the utilities and the regulatory authorities to enhance safety with the same standards, and to greatly contribute to the improvement of nuclear safety.
NRRC Risk-Informed Decision Making Workshop Report
Toward the continuous improvement of nuclear safety, Nuclear Risk Research Center conducts not only R&Ds for the implementation and further development of PRA (Probabilistic Risk Assessment) but also promotional activities for application of the risk information in the operational management of nuclear power plants.
We conducted a research on the implementation experience of Risk-Informed Decision Making (RIDM) in the United States supported by experienced experts in the US from both industry and regulation and then published a report as part of the effort.
*The report is available from the link below.
https://criepi.denken.or.jp/en/nrrc/publication.html
We also organized a workshop inviting the US experts contributing to the report. Through this workshop, NRRC expected that key players in Japan deepened understanding of the experience and lessons learned in the US and obtain specific insights toward the proper application of RIDM in Japan.
| Date | June 1, 2017 (Thu.) 9：30-16：50 |
|---|---|
| Place | Conference Room 31, Komae Area, Central Research Institute of Electric Power Industry (CRIEPI) |
| Participants | (Lecturers)
(Participants): Total 91
|
| Agenda |
|
