The International Atomic Energy (IAEA) Task Force established to monitor Japan’s plan to discharge treated water from the Fukushima Daiichi NPP has completed its second regulatory review. During a five-day visit to Japan, the Task Force met with officials from the Nuclear Regulation Authority (NRA) to assess the regulatory framework for the discharge. This was IAEA’s second review of the plans.

In early 2021, Japan announced its Basic Policy for discharging the water stored in tanks into the sea following its treatment by the Advanced Liquid Processing System (ALPS) filtration system. Japan then asked IAEA to review the safety of its implementation and Director General Rafael Grossi appointed a Task Force of independent experts and IAEA staff to carry out a review. This looks at three areas – regulatory, technical and independent sampling and analysis – to assess whether they meet international safety standards.

The NRA, set up in 2011 after the Fukushima accident, is responsible for conducting the national regulatory review and approving Tepco’s l plans to discharge the ALPS treated water into the sea. The Task looks at how NRA implements the relevant regulatory requirements, and monitors Tepco’s adherence to those requirements.

The latest talks covered the authorisation process and associated regulatory requirements plant operator Tokyo Electric Power Company Holdings (Tepco) must meet to prepare for independent monitoring by NRA. They also discussed NRA’s efforts to communicate with the public about the discharge. The Task Force observed that NRA had taken full account of the issues raised during the last review mission in March 2022. Discussions addressed the Task Force’s need for greater clarity on the criteria upon which NRA based their review of Tepco’s revised implementation plan. In addition, the Task Force was given updates on how NRA will revise its authorisation in the future if there is a change in Tepco’s monitoring data or radiological environmental impact assessment.

“NRA prepared thorough evidence of how they are aligning the regulatory plans related to the ALPS treated water discharge with the IAEA safety standards,” said Gustavo Caruso, a Director within the IAEA Department of Nuclear Safety & Security and Chair of the Task Force. “The Task Force welcomed NRA’s open and transparent approach to answering our questions.”

The Task Force also visited the Fukushima Daiichi site to observe the first of a series of pre-service inspections that NRA will carry out over the next few months before deciding on the final authorisation to begin the discharges of ALPS treated water. NRA’s inspections will verify that Tepco is preparing for the discharge of the ALPS treated water in a manner that is consistent with their approved implementation plan.

The Task Force’s first pre-service inspection involved pressure testing of pipes that were installed as part of the facilities for the ALPS discharge. It concluded that this demonstrated that the NRA is implementing an appropriate inspection programme focusing on safety-significant aspects of the planned discharge.

A report on the mission documenting progress and relevant observations will be released in about three months. Before any water discharge begins IAEA will issue a comprehensive report containing the collected findings and conclusions of the Task Force across all aspects of the review conducted as of that time. The discharge is scheduled to begin later this year.

Image: The IAEA task force inspect tanks of treated water at the Fukushima Daiichi site (courtesy of Tepco)