Tokyo Electric Power Company Holdings Inc (TEPCO) has completed the third year of releasing treated radioactive water from the damaged Fukushima Daiichi nuclear plant into the sea, with a total of 172,700 tonnes discharged over 22 rounds.
The volume of water stored at the facility has fallen by 7.6 per cent to around 1.24 million tonnes. Of approximately 1,000 storage tanks, 17 have been dismantled after being emptied as part of efforts to make space for the plant’s ongoing decommissioning work.
TEPCO plans to continue the releases until 2051, in line with the expected timeline for decommissioning the Fukushima plant. The International Atomic Energy Agency (IAEA), together with the Japanese government and TEPCO, is monitoring the process, while no abnormal levels of tritium have been detected in nearby seawater or seafood.
Japan approved the release plan in April 2021, saying the move was necessary to free up space for facilities needed to remove melted fuel debris from the reactors. TEPCO began discharging the treated water on August 24, 2023, despite objections from fishing industry operators.
The Fukushima nuclear disaster began in 2011 after a massive earthquake and tsunami struck Japan. The plant continues to generate around 60 tonnes of radioactive wastewater each day as water is used to cool melted reactor fuel.
The wastewater is treated using an advanced liquid processing system before being diluted with seawater to less than one-40th of the concentration permitted under Japan’s safety standards. It is then discharged from a facility located about 1 kilometre offshore.
Before each release, the treated water is transferred from storage tanks into separate tanks where its radioactive concentrations are measured and confirmed. The water is subsequently released in batches of approximately 7,800 tonnes.
TEPCO carried out four discharge rounds in fiscal 2023, followed by seven each in fiscal 2024 and 2025. After modifying its operations to enable continuous transfers between tanks, the company plans to conduct eight releases during fiscal 2026, with four already completed.
The releases have also affected Japan’s seafood trade. China, previously the largest destination for Japanese seafood exports, imposed a blanket ban on Japanese seafood imports when the discharge began.
Although Beijing announced in June last year that it would lift the ban for most of Japan, restrictions remained on products from 10 prefectures, including Fukushima. In practice, imports have continued to be largely halted amid a wider diplomatic dispute linked to Japanese Prime Minister Sanae Takaichi’s remarks in November last year concerning a potential crisis involving Taiwan.
Russia and several other countries and territories also continue to maintain import restrictions on Japanese seafood.
Meanwhile, TEPCO has paid compensation to businesses affected by losses linked to the water releases. As of August 5, around 1,100 claims had been processed, involving approximately 96.7 billion yen (US$608 million).
The company said many of the claims were related to businesses being unable to export seafood such as scallops and sea cucumbers to China and Hong Kong.
TEPCO chief decommissioning officer Akira Ono said the company had been able to carry out the releases safely and would continue providing accurate information while ensuring appropriate compensation for affected businesses.
