Japan will release more than one million tonnes of radioactive water from the destroyed Fukushima nuclear plant into the Pacific Ocean.
The move is being fiercely opposed by Japan’s neighbours – with China calling the plan “extremely irresponsible”.
China and South Korea are calling for more consultation on the move and Taiwan has also expressed concern.
Fishing unions in Fukushima have urged the government for years not to release the water, arguing it would have a “catastrophic impact” on the industry.
The decision, long-speculated but delayed for years due to safety concerns and protests, came at a meeting of Cabinet ministers who endorsed the ocean release as the best option.
The first release of water will take place in about two years, giving plant operator Tokyo Electric Power Co (TEPCO) time
to begin filtering the water to remove harmful isotopes, build infrastructure and acquire regulatory approval.
Once it has started, the process will take decades to complete.
Japan has argued the water release is necessary to press ahead with the complex decommissioning of the plant after it was crippled by a 2011 earthquake and tsunami, pointing out that similarly filtered water is routinely released from nuclear plants around the world.
Nearly 1.3 million tonnes of contaminated water, or enough to fill about 500 Olympic-sized swimming pools, is stored in
huge tanks at the Fukushima Daiichi plant at an annual cost of about 100 billion yen ($912.66 million) – and space is running out.
Prime Minister Yoshihide Suga said: “Releasing the … treated water is an unavoidable task to decommission the Fukushima Dai-ichi Nuclear Power Plant and reconstruct the Fukushima area.”
The filtering of the water will leave only tritium, a radioactive isotope of hydrogen which is hard to separate from water.
TEPCO will then dilute the water until tritium levels fall below regulatory limits, before pumping it into the ocean.
Tritium is considered to be relatively harmless because it does not emit enough energy to penetrate human skin.
Other nuclear plants around the world routinely pump water with low levels of the isotope into the ocean.
China’s foreign ministry has said in a statement on its website: “This action is extremely irresponsible, and will seriously damage international public health and safety, and the vital interests of people in neighbouring countries.”
South Korea expressed “serious concerns that the decision could bring a direct and indirect impact on the safety of our people and surrounding environment”, adding it would step up its own radiological measuring and monitoring.
The United States noted that Japan has worked closely with the International Atomic Energy Agency in its handling of the
site.
The US Department of State said in a statement: “Japan has weighed the options and effects, has been transparent about its decision, and appears to have adopted an approach in accordance with globally accepted nuclear safety standards.”
The decision comes about three months ahead of the postponed Tokyo Olympic Games, with some events to be held as close as 60km (35 miles) to the wrecked plant.