The planned move was intended to reduce the large amount of radioactive water stored at the Fukushima plant site, while ensuring compliance with environmental and public health standards. However, the plan took around ten years to implement and the permitting process has been fraught with challenges and controversy.

In May 2022, the Japanese Nuclear Regulatory Authority (NRA) gave its initial approval to Tepco's plan to release wastewater from the destroyed Fukushima nuclear power plant into the sea, as it believes it will not cause safety problems. Tepco plans to filter the contaminated water and dilute it until the tritium level falls below 1/40th of the regulatory limit before releasing it into the ocean.

The International Atomic Energy Agency, the UN's nuclear watchdog, approved the plan in July 2023, saying it meets international standards and that the impact on people and the environment would be "negligible".

The wastewater will be released into the sea in phases: the first phase was launched in August 2023, the second in October 2023 and the third in November 2023. The fourth phase is scheduled to start by March 2024. Japan will thus release a total of 31 200 tonnes of treated cooling water diluted with seawater, with the approval of the International Atomic Energy Agency, by March 2024.

The announcement has sparked concerns from local fishermen, and objections from neighbouring China and South Korea. On news of the water release, China has imposed a ban on imports of seafood from 10 Japanese prefectures, including Tokyo and Fukushima. Seafood from the other provinces will be allowed in, but will also be subject to radiation checks and certification that it does not come from one of the banned prefectures. Russia has also imposed a ban.

There were also protests in South Korea against the decision. The South Korean government launched its own investigation, which eventually found that the water release was in line with international standards, and the decision by the International Atomic Energy Agency was accepted.

Following the Fukushima accident, the EU adopted an implementing regulation (297/2011/EU) for feed and food from Japan, which required sampling and analysis before export to the EU. This measure was repealed in July 2023.

The potential environmental impacts of discharges into the sea and their long-term consequences remain an important issue for the international community. According to an expert, Japan's coastal areas could be affected in the long term by the accumulation of non-tritium forms of radioactivity, which could ultimately damage the region's fisheries. The measure also has economic implications, such as the ban on Japanese imports, but consumer mistrust could also lead to a decline in the consumption of fisheries products in Japan and other, especially in neighbouring countries.