Japan said Thursday that China and South Korea have both discharged liquid waste containing high levels of tritium, a radioactive material, countering Beijing's criticism of Tokyo's plan to release treated water from the Fukushima nuclear power plant.

Chief Cabinet Secretary Hirokazu Matsuno also said Japan will explain to China "based on scientific perspectives" the planned water discharge into the sea from the nuclear complex, crippled by a devastating earthquake and ensuing tsunami in March 2011.

An International Atomic Energy Agency team inspects storage tanks containing treated radioactive water at the Fukushima Daiichi nuclear power station in Japan's northeast on June 2, 2023. (Photo courtesy of Tokyo Electric Power Company Holdings Inc.)(Kyodo)

Japan's standard for the release of tritium, at below 22 trillion becquerels per year, is far stricter than that of other nations including its neighbors China and South Korea, Matsuno, the top government spokesman, said at a regular press conference.

In 2021, the Yangjiang nuclear plant in China discharged around 112 trillion becquerels of tritium, while the Kori power station in South Korea released about 49 trillion becquerels of the radioactive material, Japan's industry ministry said.

On Tuesday, the International Atomic Energy Agency submitted its review of the envisioned water discharge to Japan, concluding that the country's plan aligns with global safety standards and would have "a negligible radiological impact on people and the environment."

Japan's government and Tokyo Electric Power Company Holdings Inc., operator of the Fukushima plant, hope to begin releasing the water into the Pacific Ocean around the summer after it undergoes processing to remove most of the radionuclides except tritium.

But China has urged Japan to halt the plan, saying that if Tokyo carries it out, Beijing will strengthen the inspection of imported seafood to ensure public health and food safety.

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