An apology followed after employees fled the complex’s Unit 2 reactor when a reading showed radiation levels had reached 10 million times higher than normal in the reactor’s cooling system.
Officials said levels were so high that the worker taking the measurements had withdrawn before taking a second reading.
Last night, though, plant operators said that while the water was contaminated with radiation, the extremely high reading was a mistake.
“The number is not credible,” said Tokyo Electric Power Company spokesman Takashi Kurita. “We are very sorry.”
He said officials were taking another sample to get accurate levels, but did not know when the results would be announced.
The situation came as officials acknowledged there was radioactive water in all four of the Fukushima Dai-ichi complex’s most troubled reactors, and as airborne radiation in Unit 2 measured 1,000 millisieverts per hour — four times the limit deemed safe by the government, Kurita said.
Officials say they still don’t know where the radioactive water is coming from, though government spokesman Yukio Edano has said some is “almost certainly” seeping from a cracked reactor core in one of the units.
While the discovery of the high radiation levels — and the evacuation of workers from one reactor unit — again delayed efforts to bring the deeply troubled complex under control, Edano insisted the situation had partially stabilised.
“We have somewhat prevented the situation from turning worse,” he said.
The discovery over the last three days of radioactive water has been a major setback in the mission to get the plant’s crucial cooling systems operating more than two weeks after a massive earthquake and tsunami.
The 9.0 magnitude earthquake off Japan’s northeast coast on March 11 triggered a tsunami that barrelled onshore and disabled the Fukushima plant, complicating an immense humanitarian disaster.
The death toll from the twin disasters stood at 10,668 last night, with more than 16,574 people missing, police said. Hundreds of thousands of people have been left homeless.