IAEA reports on progress at Fukushima Daiichi

04 February 2019

While much progress has already been made in decommissioning the damaged Fukushima Daiichi units, Japan must ensure it is prepared for future challenges, such as used fuel and fuel debris removal, a mission by the International Atomic Energy Agency (IAEA) has said.

Members of the mission team at the Fukushima Daiichi plant (Image: J Donovan/IAEA)

An IAEA team of experts conducted the fourth review mission of Japan's efforts towards the decommissioning of Tokyo Electric Power Company's (Tepco's) damaged Fukushima Daiichi nuclear power plant between 5 and 13 November 2018. The team comprised 13 senior experts, including nine from the IAEA and four others from Indonesia, Russia, the UK and the USA.

The mission, which followed two previous reviews in 2013 and one in 2015, examined a wide range 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 used fuel assemblies and retrieval of fuel debris, management of radioactive waste, and institutional and organisational matters. The mission was conducted based on the IAEA Safety Standards, technical guidance and other relevant good practice, aimed at assisting the Japanese government in the implementation of its mid- to long-term roadmap for decommissioning units 1 to 4.

The team submitted its preliminary summary report at the conclusion of the mission on 13 November. Its final report was delivered to Japanese authorities on 30 January and contains additional details and expands on the preliminary summary report.

"Since March 2011, addressing the situation of the damaged plants of Fukushima Daiichi and moving towards decommissioning while ensuring safety for the workers and the population has remained a very challenging task, requiring resources, commitment, and innovation to tackle a unique situation," the team said. "The IAEA Review Team considers that significant progress had already been accomplished to move Fukushima Daiichi from an emergency situation to a stabilised situation. This should allow the focus of more resources for detailed planning and implementation of the decommissioning project of the whole site with considerations extended up to the completion of the decommissioning."

The mission team noted, "The organisation put in place by the Japanese government, with clarified roles and responsibilities of the main actors ... allows for more effective planning and implementation of the radioactive waste management and decommissioning."

The IAEA team said that daily activities at the Fukushima Daiichi site are "well managed" and noted many improvements since the previous mission in 2015, particularly in the areas of water management and solid waste management. Working conditions at the site have also improved, it said.

"The risk reduction strategy is being implemented at a pace commensurate with the challenges of the site-specific situation," the team said, noting progress being made towards the removal of used fuel from unit 3 and then units 1 and 2. The team said Tepco should ensure there is sufficient storage capacity to accommodate all used fuel on site from units 1-6. It also advised there should be a "clear implementation plan defined to safely manage the retrieved material" before fuel debris removal begins. "Whilst significant progress has been achieved in estimation of the fuel debris distribution inside the reactor buildings of units 1-3, there is recognition that more must be done."

The team said the issue of water management is "critical to the sustainability of decommissioning activities".

"Considering the challenges ahead towards the safe decommissioning of the site, the IAEA Review Team encourages Japan to further strengthen programme and project management and related organisational structure for comprehensive and integrated planning for the completion of the site decommissioning."

The team said, "The implementation of the safe decommissioning of the Fukushima Daiichi nuclear power station is a unique complex case and expected to span several decades: the IAEA Review Team considers that it will therefore require sustained engagement with stakeholders, proper knowledge management, and benefit from broad international cooperation."

Researched and written by World Nuclear News