The operator of the disaster-stricken Fukushima Daiichi nuclear power plant apologized to the local government on Thursday for a radioactive water leak from a building on the premises.

Tokyo Electric Power Company Holdings Inc. said 5.5 tons leaked from an outlet connected to a device to treat contaminated water, which is accumulating at the complex that suffered reactor fuel meltdowns in the wake of the 2011 earthquake and tsunami disaster.

Tatsuya Taminami (L), the head of the disaster-stricken Fukushima Daiichi nuclear power plant, apologizes in Fukushima, the capital city of Fukushima Prefecture, on Feb. 8, 2024. (Kyodo)

TEPCO said the latest incident has not affected the environment outside the plant.

"We made people in Fukushima Prefecture, and broadly people in the society anxious," Tatsuya Taminami, the head of the plant, said in apology as he met with prefectural officials. The prefecture asked for steps to prevent such leaks from happening again.

The leak was noticed on Wednesday morning and had occurred while washing the water treatment device located inside an incinerator building.

The 5.5 tons of water, estimated to have contained 22 billion becquerels of radioactive substances, is believed to have partially seeped into the ground and TEPCO plans to remove the potentially affected soil.

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