Publication of the Report on the Analytical Results of the Additional Measures under the IAEA Framework related to the Discharge of ALPS Treated Water into the Sea

On November 4, the IAEA published a report on the analytical results of ALPS treated water diluted with seawater prior to the discharge into the sea. The samples were collected in December 2025 on the premises of Tokyo Electric Power Company Holdings (TEPCO)’s Fukushima Daiichi Nuclear Power Station (FDNPS) by TEPCO, IAEA

officials and experts from third-party laboratories in China, the Republic of Korea, Russia and Switzerland selected by the IAEA, as part of the additional measures under the IAEA framework.

1. In the published report, the IAEA concluded that the results reported by the participating laboratories are consistent with the IAEA Comprehensive Report on the Safety Review of the ALPS-Treated Water released in July 2023, which concluded that the discharges as planned would have a negligible radiological impact on people and the environment.
2. The Government of Japan will continue to maintain close coordination with the IAEA in sharing information with the international community in a highly transparent manner and fostering a better understanding of the safety of the discharge of ALPS treated water within both the domestic and international communities.

(Reference1) Past missions for conducting the additional measures

• 1st: October 15, 2024 (collection of seawater)
• 2nd: February 19, 2025 (collection of seawater), February 20, 2025 (selection of fishery products), February 21, 2025 (collection of ALPS treated water prior to dilution with seawater)
• 3rd: April 15, 2025 (collection of ALPS treated water diluted with seawater prior to the discharge into the sea)
• 4th: June 17, 2025 (collection of ALPS treated water prior to dilution with seawater)
• 5th: September 9, 2025 (collection of seawater), September 10, 2025 (selection of fishery products)
• 6th: December 5, 2025 (collection of ALPS treated water diluted with seawater prior to the discharge into the sea)
• 7th: February 4, 2026 (collection of seawater), February 5, 2026 (selection of fishery products)
• 8th: May 29, 2026 (collection of ALPS treated water prior to dilution with seawater)
• 9th: June 24, 2026 (collection of seawater), June 25, 2026 (selection of fishery products)
• 10th: July 9, 2026 (collection of ALPS treated water diluted with seawater prior to the discharge into the sea)
• 11th: September 11, 2026 (collection of ALPS treated water prior to dilution with seawater)
• 12th: October 7, 2026 (collection of ALPS treated water diluted with seawater prior to the discharge into the sea)

(Reference2) Related links

• The IAEA Press Release
• The report on “Additional Measures” for Independent Sampling and Analysis Related to Discharges of ALPS Treated Water - Additional Measure December 2025 (PDF)

(Reference3) ALPS treated water

ALPS treated water is water which is processed by devices such as ALPS (Advanced Liquid Processing System) to ensure that the concentration of the radioactive materials other than tritium surely meet the regulatory standards for safety. In addition, ALPS treated water is sufficiently diluted before discharge into the sea so that radioactive materials, including tritium, are far below the regulatory standards for safety.