The IAEA Conducted the Fifth Review Mission on the Safety of the Discharge of ALPS Treated Water into the Sea since the Start of the Discharge into the Sea

Six IAEA officials, including Mr. Gustavo Caruso, Coordinator, Department of Nuclear Safety and Security, and nine international experts (from Argentina, Canada, China, France, Republic of Korea, Russia, the United Kingdom, the United States, and Vietnam), visited Japan for the review mission regarding the safety of the discharge of ALPS treated water from TEPCO’s FDNPS into the sea. This is the fifth review mission since the start of the discharge into the sea.

During the review mission, the IAEA Task Force discussed technical matters regarding the safety of the discharge of ALPS treated water into the sea based on the IAEA international safety standards and visited TEPCO’s FDNPS to review the site. 

The following is a summary of the discussions and the site visit to TEPCO’s FDNPS.

1. Overview of Meetings during the Review

On Monday, December 15, the opening session was held at MOFA.
On Thursday, December 18 and on Friday, December 19, METI and TEPCO (1) provided the updates on the status of the discharge of ALPS treated water from December 2024 to December 2025 and the results of sea area monitoring since the start of the discharge, etc. with the IAEA Task Force. Also, (2) they discussed the effort after the start of the discharge based on the IAEA international safety standards, with the IAEA Task Force.

• IAEA Task Force
  (Discussion with Japan side)
• Mr. Gustavo Caruso
  (Head of the IAEA Task Force)

2. Overview of Site Visit to TEPCO’s FDNPS during the Review

On Wednesday, December 17, the IAEA Task Force visited TEPCO’s FDNPS to receive a briefing from TEPCO on the latest situation at the site. Furthermore, the IAEA Task Force visited to review the following sites: the facilities related to the discharge of ALPS treated water into the sea such as ①ALPS treated water transfer facility building, ②discharge vertical shaft; and ③J8 area tanks scheduled to begin dismantling within the fiscal year 2025 and the J9 area where the tank dismantling has already been completed. In addition, the IAEA Task Force visited to review the facilities for measurements and analysis of ALPS treated water such as ④TEPCO’s chemical analysis laboratory, ⑤the IAEA Fukushima ALPS Laboratory.

• ALPS treated water
  transfer facility building
• Discharge vertical shaft

• J8・J9 area
• TEPCO’s chemical analysis laboratory

• IAEA Fukushima ALPS Laboratory

3. Future Initiatives

Through the IAEA review, the Government of Japan will take measures in accordance with international safety standards and take all possible measures to ensure the safety of the discharge of ALPS treated water. We will continue to maintain close coordination with the IAEA in sharing information with the international community in a highly transparent manner and work on fostering better understanding of the safety of the discharge of ALPS treated water both domestically and internationally.

Related website

• Visit of IAEA officials and international experts for a review on the discharge of ALPS treated water from TEPCO’s Fukushima Daiichi Nuclear Power Station into the Sea (December 8, 2025)
• The IAEA Published a Report on its Fourth Review Mission of Safety Related Aspects of the Discharge of ALPS Treated Water into the Sea After the Start of the Discharge (September 16, 2025)
• The IAEA Published a Report on its Third Review Mission of Safety Related Aspects of the Discharge of ALPS Treated Water into the Sea after the Start of the Discharge (March 25, 2025)
• The IAEA Published a Report on Its Second Review Mission of Safety Aspects of Handling of ALPS Treated Water at Fukushima Daiichi Nuclear Power Station since the Start of the Discharge in April 2024 (July 18, 2024)
• The IAEA Published a Report on Its First Review Mission of Safety Aspects of Handling of ALPS Treated Water at Fukushima Daiichi Nuclear Power Station since the Start of the Discharge in October 2023 (January 30, 2024)
• Publication of the IAEA Comprehensive Report on the Safety Review of the ALPS Treated Water at TEPCO’s Fukushima Daiichi nuclear Power Station (FDNPS) (July 4, 2023)
• Let's get to know and understand about ALPS treated water. [Ministry of Economy, Trade and Industry]
• IAEA Website about ALPS treated water

Division in Charge

Nuclear Accident Response Office, Agency for Natural Resources and Energy