For the Fifth ILC Conducted by the IAEA, ALPS Treated Water Before Dilution with Seawater Was Sampled

Jul 16, 2026

The International Atomic Energy Agency (IAEA) has been conducting Interlaboratory Comparisons (ILCs) since 2022 to corroborate Tokyo Electric Power Company Holdings (TEPCO)'s proficiency in monitoring the ALPS treated water.

On Thursday July 16, for the conducted by the IAEA, TEPCO collected samples of the ALPS treated water before dilution with seawater from the Measurement/Confirmation Tanks on the premises of TEPCO's Fukushima Daiichi Nuclear Power Station (FDNPS), with IAEA officials observing the process.

This ILC is the fifth one, following the fourth ILC conducted in July 2025, when samples of ALPS treated water were collected.

The samples collected this time will be analyzed for radioactive substances by the IAEA and laboratories in China, the Republic of Korea, and the Swiss Confederation.

The monitoring activities, which have been conducted since 2022 based on the "Terms of Reference (TOR) on a comprehensive framework for reviewing safety related aspects of handling ALPS treated water" signed between the IAEA and the Japanese government, aim to carry out sampling, independent analysis, and data corroboration. During these monitoring activities, the IAEA and laboratories in third-party countries will conduct independent analyses and compare their results with those of TEPCO in order to corroborate TEPCO's proficiency in monitoring the ALPS treated water.

〔Reference 2〕Measurement/Confirmation Tanks
The tanks used to receive ALPS treated water from the storage tanks, etc., on the premises of TEPCO's FDNPS, and to circulate and agitate ALPS treated water to collect representative samples for the analysis prior to the dilution and discharge.