IAEA Conducts Sixth Review Mission on the Safety of ALPS Treated Water Discharge into the Sea since the Discharge Began

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

During the review mission, the IAEA Task Force discussed technical matters based on the IAEA international safety standards, focusing on Japan’s efforts in the monitoring conducted on the premises of TEPCO’s FDNPS and the sea area monitoring related to the discharge of ALPS treated water, 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, May 11, the opening session was held at the Ministry of Foreign Affairs (MOFA).

On Monday, May 11, Tuesday, May 12, and Thursday, May 14, the Government of Japan (MOFA, the Ministry of Economy, Trade and Industry, the Nuclear Regulation Authority, the Ministry of Environment and the Fisheries Agency), Fukushima Prefecture and TEPCO (1) provided the IAEA Task Force with the information on the overview and the results of the monitoring conducted on the premises of TEPCO’s FDNPS and the sea area monitoring related to the discharge of ALPS treated water into the sea, and (2) explained the consistency of the monitoring with the international safety standards followed by a discussion 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, May 13, the IAEA Task Force visited TEPCO’s FDNPS to receive a briefing from TEPCO on the latest situation at the site.

The IAEA Task Force visited (1) the elevated area overlooking Units 1 to 4 (Blue Deck) and received an explanation on the progress of the decommissioning. In addition, they reviewed the facilities for monitoring related to the discharge of ALPS treated water into the sea such as (2) the ALPS treated water transfer facility building and (3) the discharge vertical shaft; and (4) the J8 area, where the dismantling of the tanks is being conducted, and the J9 area, where the dismantling of the tanks has been completed.

• Blue Deck
• ALPS treated water transfer facility building

• Discharge vertical shaft
• J8 and J9 areas

Photos courtesy of TEPCO

Related Links

• 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 (MOFA)
• The IAEA Published a Report on its Fifth Review Mission of Safety Related Aspects of the Discharge of ALPS Treated Water into the Sea after the Start of the Discharge (May 1, 2026)
• 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 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 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)
• Special Page explaining ALPS Treated Water
• Let's get to know and understand about ALPS treated water
• Fukushima Daiichi ALPS Treated Water Discharge (IAEA)

Division in Charge

Nuclear Accident Response Office, Agency for Natural Resources and Energy