Release of diluted Fukushima cooling water finally approved

The Fukushima Daiichi nuclear power station.

A tank farm grown up around the crippled Fukushima Daiichi nuclear power station, built to hold treated cooling water from the reactor, will soon begin releasing diluted water as the tanks near capacity.

The debate over the cooling water has gone on for years, with multiple groups objecting to any release of water. Fishery cooperatives, some local mayors, and South Korea and China all object to the plan, but Japan’s Nuclear Regulation Authority approved it on 18 May. Following the approval, International Atomic Energy Agency (IAEA) Director General Rafael Mariano Grossi visited the reactor site, operated by Tokyo Electric Power Company Holdings Inc. (TEPCO) and then met with Prime Minister Fumio Kishida in Tokyo on 20 May.

“Japan has made significant progress in its preparations, and the IAEA Task Force is satisfied that TEPCO and METI (Ministry of Economy, Trade and Industry) have identified the appropriate next steps for the water discharge scheduled for 2023,” Kishida said. “The IAEA is committed to providing a thorough safety review before, during and after the release of treated water and to carrying out our work in an objective and transparent manner.”

According to TEPCO, the water has been treated with an “advanced liquid processing system” (ALPS) to remove most radioactive isotopes, including cesium and strontium – but tritium is difficult to separate from water, because it closely resembles hydrogen, which is a natural component of water. TEPCO plans to dilute the stored cooling water with seawater to bring tritium to within allowable levels and release it to the ocean via a kilometer-long underwater pipe.

The plan that was approved was released by TEPCO in a 13 May press release, and contains a detailed document of over 1,110 pages, detailing some changes to earlier planning made in response to public opinions and feedback from Japan’s Nuclear Regulation Authority, which gave its approval to start discharging the water in early 2023.

A survey of local mayors in Fukushima and nearby prefectures of Iwate and Miyagi, found that nearly 60 percent opposed the release. The main reasons were the fishery cooperatives in those prefectures oppose it, and that understanding of the plan by local residents and foreign countries had not been gained.

For the fishermen, there is not so much actual danger as there is reputational risk and consumer unease. The fishery cooperatives are worried about whether consumers will trust the safety of their products.

To address concerns over the salability of their fish, the government created a fund to buy and store seafood products that can be frozen or to help fishermen expand sales channels for those that cannot be frozen, if domestic or export demand for seafood drops sharply as a result of the release. The government has given instructions to TEPCO to create a plan for compensating fishermen in case they suffer losses as a result of any harm caused by the release, including reputational harm.

Regarding possible risks to U.S. fisheries, the Food and Drug Administration said “Tritium presents an extremely low human and animal health risk if consumed and any health risk would be further minimized with the dilution effects of discharge into the ocean.”

The reason tritium is not very risky to health compared with some other radioactive isotopes is the same reason it is difficult to isolate. Because it resembles hydrogen molecules, it tends to take the place of hydrogen in water and is then expelled from the body rather than accumulating.

South Korea previously criticized the plan to release the water, citing insufficient consultation. However, the IAEA team that will monitor the release was joined in July 2021 by Dr. Kim Hong-suk, from the Korea Institute of Nuclear Safety. The team includes experts from 11 countries, including the United States, France, and China.

Japanese media has speculated that the newly elected government of Yoon Suk-yeol would approve of the plan, but the South Korean Foreign Ministry clarified on 20 May that it has never approved of the plan. South Korea’s Oceans Minister, Cho Seung Hwan, on 25 May, further said that the country would not be lifting its ban on imports of Japanese seafood from areas affected by the 2011 Fukushima explosion, in response to speculation that it would relax the ban in order to get Japan’s support to allow it to join a regional free trade accord.

Even before the accident, tritium in cooling water was thinned with circulated sea water and released to the sea. Operational nuclear power plants routinely release diluted cooling water in to the ocean. This is also done in countries that object to the release, including South Korea.  

Photo courtesy of Santiherllor/Shutterstock


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