IAEA’s Grossi joins seawater sampling at Fukushima Daiichi

International cooperation in the monitoring of radiation levels in seawater near the disabled Fukushima Daiichi nuclear power plant continues. Scientists from China, South Korea, and Switzerland were recently joined by International Atomic Energy Agency Director General Rafael Mariano Grossi as they collected seawater samples under the "additional measures" framework, which was adapted in 2024 to increase the participation of other countries and enhance the transparency of the IAEA-led analyses.

Fukushima Daiichi was shut down after its reactors were severely damaged by a massive earthquake and tsunami in March 2011. The reactors are undergoing a decades-long decommissioning and decontamination process led by owner and operator Tokyo Electric Power Company. The company is treating contaminated water with the Advanced Liquid Processing System (ALPS), a chemical process that removes radionuclides other than tritium to below legal limits. The ALPS-treated water is stored on-site until it can be diluted with seawater-thereby lowering the tritium concentration-before being discharged into the sea.

International safety standards: Grossi, who also joined the sampling efforts last year, issued a statement stressing that the additional measures framework "enable[s] third parties to independently verify that the water discharge complies, and will continue to comply, fully with international safety standards. By welcoming countries to collect and analyze samples directly, Japan is helping to increase transparency, shared understanding, and confidence, particularly among its neighbors."

The seawater samples will be analyzed by the IAEA Marine Environment Laboratories in Monaco and by laboratories in Japan, as well as the laboratories of the Third Institute of Oceanography in China, the Korea Institute of Nuclear Safety in South Korea, and the Spiez Laboratory in Switzerland.

Negligible radiological impact: Since TEPCO began discharging the ALPS-treated water in August 2023, more than 156,000 cubic meters have been diluted and released in 20 batches. The IAEA has reported that the tritium levels in all the batches that have been released so far "were far below Japan's operational limit." An IAEA report last September reaffirmed findings in the agency's 2023 comprehensive report, which, as previously reported by Nuclear Newswire, "found that TEPCO's plans for discharging Fukushima water would have a negligible radiological impact on people and the environment." With ongoing monitoring, TEPCO plans to discharge more treated water in a series of batches over the coming decades.

Furthermore, according to Japan's Nuclear Regulation Authority, as of this past May, radiation levels throughout about 70 percent of Fukushima Prefecture are in line with the national average of 0.1 microSieverts per hour, and more than 90 percent of the prefecture has levels below 0.2 μSv per hour. The authority has found no harmful effects from radiation among local people nor any doses approaching harmful levels.

Live online data: The IAEA "will continue its impartial, independent and objective safety review of the ALPS treated water discharge, by having a continuous onsite presence, corroborating monitoring data through Interlaboratory Comparisons and providing live online monitoring," the agency has stated.