IAEA Confirms Fukushima ALPS Water Discharge Meets Global Safety Standards in Review

During the mission, the Task Force carried out on-site inspections, reviewed operational data, and met with key Japanese ministries and agencies overseeing the discharge.

The International Atomic Energy Agency (IAEA) Task Force has reaffirmed that Japan’s discharge of ALPS-treated (Advanced Liquid Processing System) water from the Fukushima Daiichi Nuclear Power Station (FDNPS) continues to align with international safety standards. The confirmation came after a five-day mission conducted from 15 to 19 December, marking the Task Force’s tenth review mission since 2021.

IAEA Reaffirms Safety Compliance

During the mission, the Task Force carried out on-site inspections, reviewed operational data, and met with key Japanese ministries and agencies overseeing the discharge. Their findings build upon the IAEA’s Comprehensive Report issued in July 2023, which concluded that Japan’s approach remains consistent with global radiation protection guidelines and poses negligible radiological impact to people or the environment.

The Task Force consists of IAEA experts and 11 international specialists from Argentina, Australia, Canada, China, France, the Marshall Islands, the Republic of Korea, the Russian Federation, the United Kingdom, the United States, and Viet Nam. This diverse participation underscores the review’s transparency and international credibility.

“Japan has demonstrated continued effort and commitment to ensuring that the discharge of ALPS-treated water is implemented in line with relevant international safety standards,” said Gustavo Caruso, Chair of the Task Force. “The IAEA will continue its independent review to provide transparency and compliance throughout the entire discharge process.”

Focus of the December 2025 Mission

The mission evaluated activities carried out since the start of the discharge in August 2023 and reviewed several technical areas central to safety oversight. In Tokyo, Task Force members held discussions with:

• The Ministry of Foreign Affairs

• The Nuclear Regulation Authority

• The Ministry of Economy, Trade and Industry

• Tokyo Electric Power Company Holdings (TEPCO), the operator of FDNPS

At the Fukushima site, experts conducted their fifth inspection of the ALPS-treated water discharge facilities. They examined:

• Discharge equipment and pipelines

• Tritium measurement procedures

• Laboratory analysis conducted in TEPCO’s Chemical Analysis Building

• The IAEA’s on-site laboratory operations

These inspections enabled the Task Force to independently observe monitoring procedures, including sampling, analytical methods, and real-time radiation measurement systems.

Progress in Tank Dismantling and Decommissioning

The Task Force noted continued progress in the dismantling of tanks that previously stored ALPS-treated water. These activities are part of Japan’s broader decommissioning plan for Fukushima Daiichi, aiming to safely remove older storage structures as water continues to be processed and discharged under controlled conditions.

All reviewed equipment and facilities were found to be operated in accordance with:

• Japan’s official Implementation Plan

• Relevant IAEA safety standards

• International best practices for radiation protection

Verification Through Independent Monitoring

The IAEA continues to independently verify the accuracy of data provided by TEPCO and the Government of Japan. This includes:

• Interlaboratory comparisons, conducted since before the discharge began

• On-site sampling and analysis, ongoing since July 2023

• Real-time monitoring of radiation levels and water flow rates, streamed on the IAEA’s public monitoring portal

Results from the first 17 batches of diluted ALPS-treated water confirm that tritium concentrations remain far below operational limits and are consistent with international safety benchmarks.

Expanded International Participation and Transparency

In addition to routine oversight, the IAEA performs additional transparency measures that allow international experts to conduct hands-on independent measurements. The latest of these special missions took place in December 2025, further strengthening global trust in the monitoring programme.

Final Assessment and Next Steps

The Task Force concluded that there are no inconsistencies between current discharge practices and international safety requirements. This reaffirms earlier assessments from the 2023 Comprehensive Report.

A detailed report on the December mission’s findings will be published next year, joining previous reports from the first four review missions conducted since the start of the discharge. These documents remain publicly accessible to ensure full transparency and global accountability.