Workers at Japan's troubled Fukushima Daiichi nuclear complex continued Sunday to struggle to contain highly radioactive water that is hampering work to restore vital systems, as they also tried to prevent further spreading of radioactive materials to surrounding areas.
But it was unclear late Sunday night just how severe the problem really was. Earlier in the day, workers were evacuated from one of the reactors when the company running the plant announced that radiation had been detected at an eye-popping 10 million times normal levels. But later Sunday evening, a spokesman for the plant's operator—Tokyo Electric Power Co., or Tepco—said the utility company was "re-analyzing the figure after it was pointed out internally and also by the Nuclear Safety Commission that it might be calculated incorrectly."
The spokesman, Hiro Hasegawa, said a new figure would be issued sometime after midnight Japan time. "The Tepco numbers were a bit odd or strange," Hidehiko Nishiyama, a senior official at Japan's Nuclear and Industrial Safety Agency, or NISA, told reporters earlier in the evening.
The reported rise in radioactivity added to concerns that efforts to keep nuclear fuel at the Fukushima Daiichi facility from overheating and sustaining further damage, which increases the risk of greater radiation leaks, may suffer further delays.
Previous spikes in radiation levels, both airborne and in water collecting at the site, have repeatedly forced stoppage of scheduled work. Three workers were injured several days ago at the No. 3 reactor after coming into contact with a pool of water that had a reading of 750 millisievert per hour, suggesting the health risks to workers are now even more dire.
Highlighting the inability of authorities so far to confidently pinpoint the source of the leaks, a key step to stanching them, the government's chief spokesperson said Sunday morning that he wasn't sure where the water was coming from.
Chief Cabinet Secretary Yukio Edano, speaking on national broadcaster NHK Sunday, said only that "we will analyze where the highly radioactive water is coming from."
The lack of unity in the message from authorities, with Mr. Nishiyama speculating that the water is likely from the reactor core while Prime Minister Naoto Kan's spokesman declined to go that far, may also add to concern over the government's response nearly two weeks after Mr. Kan appointed himself chief of a crisis team.
Authorities said they were attempting to pump the radioactive water to the condenser units that allow steam from the reactor to cool down so that workers could continue their efforts to lay power cables and perform checks in order to bring the plant's systems back on line.
In a sign of the broadening scale of contamination in the vicinity of the plant, seawater collected Saturday afternoon near the plant contained concentrations of radioactive iodine-131 at 1,850 times Japan's legal limit, up from concentrations 1,250 times the limit in water collected the day before, the government said Sunday.
Mr. Nishiyama said authorities plan to switch from fire trucks to electric pumps to inject water into the cores of reactors Nos. 1-3. It wasn't immediately clear if this work, which could bring more sustainability to the crucial task of cooling the nuclear fuel, could proceed if radiation levels were highly elevated.
Meanwhile, Mr. Nishiyama said work is continuing to drain a highly radioactive pool of water in the turbine building of the No. 1 reactor. He also said that starting Monday authorities intend to start using fresh water, instead of the seawater used so far, to douse the spent fuel pool in the No. 4 reactor. The same switch is scheduled to be made at the No. 1 reactor starting Tuesday, Mr. Nishiyama said.
Switching to fresh water from seawater, which has been used for many days, in the cooling process is necessary to stem some problems in the rescue effort. Seawater cooling often worsens water circulation of the cooling pump because of accumulation of crystallized salt.
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