Japan has announced that the contaminated water stored in the Fukushima nuclear power plant will be discharged into the sea in the Pacific Ocean in the coming years. Since the tsunami of ten years ago, which caused the partial melting of the kernels of three of the plant's six reactors, Tokyo Electric Power Co. (Tepco), the energy company that manages the plant, has accumulated more than one million tons of water in more than a thousand large cisterns: it was used to cool the reactors, which is why it is radioactive.
It has been known for some time that by 2022 in the tanks available around the plant there will be no more space to contain all the water used in the dismantling of the plant; for this reason, there had been talk of possible solutions for years.
The Japanese government has assessed that dispersing it at sea is the best choice, after having removed many of the radioactive elements it contained. The only element that cannot be completely removed is tritium, a radioactive isotope of hydrogen: it is relatively unsafe for human health and is naturally present in sea water and the atmosphere.
However, the decision has been highly contested by environmentalists as well as by neighboring countries to Japan, such as China and South Korea, which consider it extremely dangerous both for health and for the economy linked to fishing. The United States, on the other hand, supported the Japanese government, and maintained that the decision was made in a "transparent" manner.
The Japanese government has said that work to put the water into the sea will begin within two years, and it will take at least ten to complete.