An International Atomic Energy Agency (IAEA) team of experts has completed the fourth review mission of Japan’s efforts towards the decommissioning of the Fukushima Daiichi Nuclear Power Station (NPS). The International Peer Review of Japan’s Mid-and-Long-Term Roadmap Towards the Decommissioning of TEPCO’s Fukushima Daiichi Nuclear Power Station took place from 5 to 13 November 2018.
The IAEA team said Japan has made significant progress since the accident in March 2011, advancing from an emergency situation towards a stable situation now. The team said this achievement will now allow Japan to focus more resources on detailed planning and implementation of decommissioning activities of the whole site, with considerations extended up to completion.
“Given the severity of the challenges faced from the outset of the accident, one can only be impressed by the dedication and the achievements of the people involved,” said team leader Christophe Xerri, Director of the IAEA’s Division of Nuclear Fuel Cycle and Waste Technology.
“Despite these achievements, many challenges remain to be tackled in the decommissioning process, and ensuring safety in this complex situation requires sustained daily attention.”
The mission, which followed two previous reviews in 2013 and one in 2015, examined a wide variety of issues at Fukushima Daiichi. The team reviewed progress since the 2015 mission, the current situation on site and future plans in areas such as water management, removal of spent fuel assemblies and retrieval of fuel debris, management of radioactive waste, and institutional and organizational matters.
The team held extensive discussions with officials from the Ministry of Economy, Trade and Industry (METI), the Tokyo Electric Power Company (TEPCO) and the Nuclear Damage Compensation and Decommissioning Facilitation Corporation (NDF)—the national entity responsible for the decommissioning strategy for Fukushima Daiichi NPS—as well as other authorities. The team also visited the Fukushima Daiichi site to obtain first-hand information about the conditions and progress towards decommissioning.
In its Preliminary Summary Report delivered to Japanese authorities on November 13, the team acknowledged a number of accomplishments since the 2015 mission, including:
- The repair of subdrains and construction of the frozen soil wall around reactor Units 1-4, which have reduced groundwater ingress into the reactor buildings.
- The construction of storage and processing facilities for the safe management of solid radioactive wastes.
- Improved site working conditions including a reduced need for full protective gear, and real-time radiation monitoring easily accessed by the workforce.
- Progress towards the removal of spent fuel from Units 1-3 as well as remote investigations of fuel debris by robots.
The team encouraged Japan to continue carrying out and enhancing its strategy for safely decommissioning and managing radioactive waste, and identified water management as critical to the sustainability of the overall project.
The team said the Government of Japan, in engaging all stakeholders, should urgently decide on a disposition path for treated water containing tritium and other residual radionuclides. The treated water is accumulating in tanks on site and is expected to reach the currently planned tank capacity within three to four years. The water may require further treatment to reduce radionuclides to authorized levels before any of the five disposition paths considered by the Government (ground injection, controlled discharge into the sea, discharge as steam, discharge as hydrogen, and solidification for underground burial) can be implemented. A decision on the disposition path is needed soon to ensure a safe and sustainable decommissioning and can only be implemented after a regulatory review, with the support of a robust environmental monitoring programme and a communication plan.
In addition, the team provided advice in areas where practices could be enhanced, including the provision of resources for comprehensive and integrated planning for the completion of decommissioning, and more detailed, long-term planning for managing wastes arising from the decommissioning project.
The team comprised 13 senior experts, including nine from the IAEA and four others from Indonesia, the Russian Federation, the United Kingdom and the United States. The team plans to deliver its final report to the Government by the end of January.