The NEA Working Group on Reactor Oversight (WGRO) organised its first international workshop on 11–15 November 2024 in Fukui, Japan. It consisted of two sessions:

• Session 1 (Days 1, 2, and 3) - open only to WGRO members and invited participants;
• Session 2 (Days 4 and 5) - open to participants from licensees, local governments and academia.

Reactor oversight provides a regulatory body (RB) the ability to verify that licensees, during all the phases of the performance of their activities, operate the facility safely, that their activities fully comply with all applicable regulations and that safety is given the highest priority. Reactor oversight also provides a basis for regulatory enforcement. In this framework, the main purpose of the workshop’s Session 1 was to provide a forum to participating countries to exchange technical information on regulatory oversight activities. Participants had the opportunity to meet with their counterparts from other countries and organisations to discuss current and future issues on the selected topics. They developed conclusions and commendable practices regarding these issues and identified methods to help improve their respective oversight activities.

In addition, as part of the INROW, a focused study of Japan’s reactor oversight process (ROP) activities was undertaken by international regulatory experts from the WGRO through a benchmarking inspection to observe formal interactions between onsite inspectors and licensee/operator staff and management. Key insights from the observations were used to inform a workshop that explored several areas such as inspector roles and responsibilities, organisational and cultural constraints that impede effective communication and feedback during the oversight activities through facilitated panel sessions and expert opinions.

The INROW Session 1 (Days 1-3) consisted of the following three topics* that were discussed among the WGRO members and invited participants. These topics were selected based on feedback from WGRO members and the CNRA.

1. Oversight framework regarding licensee’s cross-cutting issues
2. Inspection of licensee’s readiness for external events that could result in a station blackout
3. Innovative approaches to regulatory oversight

* For more information on each topic, please see the "INROW S1 Questionnaires”.

The INROW Session 2 (Days 4-5) included the benchmark inspection and a workshop open to a wider audience.

• Benchmark inspection (Day 4) at Ooi Nuclear Power Station was performed by international inspectors assigned by WGRO member countries, NRA’s inspectors and licensees’ site staff for the input to the case study of Japan’s ROP on Day 5.
• A workshop (Day 5) was held with invited representatives from licensees, local governments and academia as well as the WGRO members.

• 11-13 November 2024: Session 1 - open to participants from regulatory bodies, research organisations, and technical support organisations (TSOs).
• 14 November 2024: The site visit to Monju - open to all the participants of the Session 1. The benchmark inspection on Day 4 will be performed by invited inspectors only.
• 15 November 2024: Session 2 - open to participants from licensees, local governments and academia as well as the Session 1 participants.
• 18 November 2024: The Fukushima Daiichi Nuclear Power Station site visit - open to all WGRO members and other accepted participants.