Involvement of the IAEA During and After the Discharge of "ALPS Treated Water"
The IAEA is committed to engaging with Japan on the discharge of ALPS treated water over years, also during and after the discharge, and conducted reviews five times in total from the commencement of the discharge to December 2025 (in October 2023, April 2024, December 2024, May 2025, and December 2025) and published four reports. All these reports clearly state, “did not identify anything that is inconsistent with the requirements in the relevant international safety standards” and “can reaffirm the fundamental conclusions of its safety review as outlined in the IAEA Comprehensive Report.”
The IAEA conducts monitoring of radioactive materials in ALPS treated water and the environment from an independent standpoint for the purpose of corroborating the data published by the government of Japan. By December 2025, the IAEA published three reports on radioactive materials in ALPS treated water (in May 2023, January 2024 and March 2025) and two reports on radioactive materials in the environment (in January 2024 and March 2025). All these reports evaluate that TEPCO and Japanese analytical laboratories have a high degree of proficiency. Furthermore, staff members of the IAEA are stationed at TEPCO's Fukushima Daiichi NPS to check the situations of the frontline and conduct monitoring.
In September 2024, the government of Japan and the IAEA concurred on conducting the additional measures on monitoring under the framework of the IAEA. By December 2025, IAEA officials and experts from third-party analytical laboratories came to Japan and conducted sampling six times as a part of the additional measures, IAEA reports that the analytical results by the participating laboratories are consistent with the conclusions of the IAEA Comprehensive Report released in July 2023, which found that the discharges as planned would have a negligible radiological impact on people and the environment.
(Source) Prepared based on
- METI's website, “Let's get to know and understand about ALPS treated water.”
https://www.meti.go.jp/earthquake/nuclear/hairo_osensui/english/shirou_alps.html - Website of the Ministry of Foreign Affairs,“ALPS treated water Summary Document”: https://www.mofa.go.jp/files/100521833.pdf
- Included in this reference material on March 31, 2026