A sub-committee of Japanese experts advised the government on discharging tritium-contaminated water from the damaged Fukushima nuclear power plant by releasing it into the ocean, while taking precautions not to harm the region's image.

A the end of the meeting, the members of this committee set up by the Ministry of Industry (Meti), considered that “compared to evaporation, ocean release can be done more securely”, pointing to common practice around the world where normally operating nuclear stations release water that contains tritium into the sea.

“But it should be noted that the quantity of water and tritium will not be the same as what was,” said the subcommittee.

The final decision remains to be made by the government.

A massive volume of contaminated water is stored in 1,000 tanks at the site of the Fukushima Daiichi power plant, which was devastated by the March 2011 tsunami. It comes from rain, groundwater or injections needed to cool the cores of the reactors that melted after the tsunami.

Filtered several times, this water will eventually be free of most radionuclides, except for tritium, which is considered less dangerous for the environment and living beings.

Sustainable storage, as recommended by environmental organizations such as Greenpeace, was ruled out at the end of last year, leaving only dilution at sea, evaporation into the air or a combination of the two as an option.

Experts, including those at the International Atomic Energy Agency (IAEA), have been pushing for years for dilution at sea.

Even if this choice is made, it is not immediately feasible because, as Tokyo Electric Power (Tepco) has acknowledged, much of this water is still heavily loaded with other radioactive elements that are dangerous for the food chain. Eighty percent of the water currently stored must be filtered back.

However, Tepco estimates that the tanks on site will be full in 2022.

A final decision is not expected before the Tokyo Olympics this summer, given the diplomatic and image risks for the country.

Japan is likely to encounter strong opposition, which is already being expressed, from fishermen and farmers in the region, as well as from environmental organizations and neighboring countries, beginning with South Korea.