The discharge of treated water from Japan's Fukushima Daiichi Nuclear Power Station (FDNPS) is proceeding in line with international safety standards, the International Atomic Energy Agency (IAEA) Task Force confirmed today in its fourth report?since the water discharge began in August 2023. The monitoring programmes carried out for the ALPS (Advanced Liquid Processing System) treated water are also consistent with the relevant international safety standards and guidance, the report states.

During its fourth mission to Japan from 26 to 30 May 2025, the Task Force observed the ALPS treated water discharge facilities at the FDNPS and met with government and municipal officials, as well as representatives from Tokyo Electric Power Company Holdings (TEPCO) – operator of the plant – in Tokyo.

The Task Force report reaffirmed the findings of its safety review outlined in the IAEA Comprehensive Report. It highlighted that the Nuclear Regulation Authority?(NRA) has maintained regulatory oversight of the ALPS treated water through its monitoring programmes and its onsite presence. Additionally, the Task Force confirmed that the water discharge equipment and facilities are operating in accordance with relevant international safety standards.

The Task Force noted the importance of the IAEA’s ongoing corroboration activities and the IAEA onsite independent testing and analyses in providing a comprehensive, transparent and independent verification of the accuracy and reliability of the data reported by TEPCO and the Government of Japan.

The IAEA’s extensive monitoring and assessment activities for the safety review of ALPS treated water include a series of Inter Laboratory Comparisons (ILCs) which have already confirmed?TEPCO's capabilities for accurately measuring the radionuclides in the treated water stored on site, and the capabilities of Japan’s laboratories for accurate measuring of the radionuclides in seawater, sediment, fish and seaweed samples.

Additionally, IAEA experts stationed at the Agency’s office at FDNPS conduct regular independent on-site analyses of the batches of treated water. The IAEA has earlier?confirmed?that the tritium concentrations in the?15 batches?of ALPS treated water were far below operational limits.

Read the latest report for more information. All reports, as well as additional information such as frequently asked questions, can be found on the IAEA’s Fukushima Daiichi ALPS Treated Water Discharge?web page.