The programs put in place to monitor water that has been treated using the Advanced Liquid Processing System (ALPS) and released into the ocean are also consistent with the relevant international safety standards and guidance, the report states.
ALPS: Water recovered from the damaged Fukushima plant is treated using ALPS to remove radionuclides other than tritium. The ALPS-treated water is stored on-site until it can be diluted with seawater before being discharged into the ocean.
On September 11, plant operator TEPCO began to discharge its fourth batch of water for fiscal year 2025—the 15th batch discharged since 2023. According to the company, for this current discharge, the tritium concentration of water after dilution is approximately 284 becquerels per liter, well below the regulatory concentration limit (60,000 Bq/l), the World Health Organization standard for drinking water quality guidelines (10,000 Bq/l), and the value stipulated by Japan’s regulations (1,500 Bq/l).
The IAEA, which conducts regular independent on-site analyses of the batches of ALPS-treated water at the agency’s Fukushima office, had earlier confirmed that the tritium concentrations in the previous batches of ALPS-treated water were far below operational limits.
IAEA review: The report, released on September 12, is the result of the task force’s fourth mission to Japan, from May 26 to 30, which focused on reviewing and understanding the various monitoring programs being carried out for the ALPS-treated water to confirm whether TEPCO is following relevant international safety standards.
During the visit, task force members observed the ALPS-treated water discharge facilities at the Fukushima site and met with government and municipal officials, as well as TEPCO representatives in Tokyo.
The IAEA report reaffirmed the findings of its safety review outlined in the agency’s 2023 comprehensive report, which found that TEPCO’s plans for discharging Fukushima water would have a negligible radiological impact on people and the environment. The task force found that Japan’s Nuclear Regulation Authority has maintained regulatory oversight of the ALPS-treated water through its monitoring programs and its on-site 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 on-site 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.