Fifth Sampling for ALPS Treated Water Comparison

The International Atomic Energy Agency (IAEA) has conducted interlaboratory comparisons since 2022 to verify TEPCO’s capability to monitor ALPS treated water. This time, in the presence of IAEA officials, TEPCO collected ALPS treated water before seawater dilution at the TEPCO Fukushima Daiichi Nuclear Power Station. This is the fifth interlaboratory comparison, following the fourth comparison, during which ALPS treated water was collected in July 2025.

The IAEA and laboratories in third countries will independently analyze radioactive substances and compare the results with TEPCO’s analysis results to verify the company’s monitoring capability for ALPS treated water. The interlaboratory comparisons are intended to support sampling, independent analysis, and data corroboration.

The sample collected this time is scheduled to undergo analysis of radioactive substances by the IAEA and laboratories in China, South Korea, and the Swiss Confederation. The collection site was a measurement and confirmation tank at the Fukushima Daiichi Nuclear Power Station. The tank receives ALPS treated water from storage tanks and other facilities on the site and is circulated and stirred to collect representative samples for analysis before dilution and discharge. The interlaboratory comparison is based on the “Terms of Reference for a Comprehensive Framework for the Review of Safety Relating to the Handling of ALPS Treated Water,” signed by the Japanese government and the IAEA.