The International Atomic Energy Agency (IAEA) Task Force reviewing the safety of Japan’s plan to discharge ALPS (Advanced Liquid Processing System) treated water from the Fukushima Daiichi NPP into the sea has released its fourth report.

It compiles the findings from the Task Force’s second safety review mission in November 2022 to Fukushima Daiichi NPP operator Tokyo Electric Power Company (Tepco) and the Ministry of Economy, Trade & Industry (METI).

In 2021, Japan requested the Agency to undertake a comprehensive review of the safety of its plan to discharge the ALPS treated water. IAEA Director General Rafael Mariano Grossi then appointed a Task Force of independent experts and IAEA staff to carry out a three-pronged review. This involved technical, regulatory, and independent sampling and analysis against international safety standards, which constitute the worldwide reference for protecting the public and the environment from harmful effects of ionising radiation.

The new report assesses Tepco’s technical responsibilities including the safety-related aspects of the systems built to discharge the ALPS treated water, the radiological environmental impact assessment, source and environmental monitoring programmes, and occupational radiation protection. It notes that Tepco has taken account of the issues raised during the previous technical mission in February 2022 and has made significant progress to update its plans in accordance with feedback from the Task Force. Any additional revisions made since the November 2022 mission will be assessed as part of the ongoing safety review after they are finalised and also approved by Japan’s Nuclear Regulation Authority.

The Task Force said it would need to finalise the full safety review of the planned water discharge before concluding whether Tepco had addressed the fundamental safety principles.

The Task Force noted:

  • Tepco’s determination of the characteristics and activity of the ALPS treated water is used to establish and implement effective monitoring programmes to ensure that any public exposure due to the discharges is adequately considered. The report said Tepco’s revised methodology for characterising the source term is sufficiently conservative yet realistic.
  • Based on the information provided before and during the mission, the Task Force gained a better understanding of Tepco’s environmental monitoring programmes and agreed that they are comprehensive.
  • Tepco has a reliable and sustainable radiation protection programme for its employees. The report said there is clear evidence of the implementation of occupational exposure control measures and monitoring arrangements.

“The Task Force was satisfied that our observations were considered and reflected in revisions to key documents such as the Radiological Environmental Impact Assessment,” said Task Force Chair Gustavo Caruso, Director & Coordinator for the ALPS Safety Review at the IAEA Department of Nuclear Safety & Security. “We do not see a need to conduct any further technical review missions to Japan prior to the release but will use the next months to finalise our comprehensive conclusions before any discharge.”

Two more reports will be released – on regulatory and independent sampling and analysis aspects – before a comprehensive report detailing the collected findings and conclusions of the Task Force across all aspects of the review is issued later this year.

Image courtesy of METI