TOKYO — The operator of the stricken Fukushima Daiichi nuclear plant said Saturday that highly radioactive water was leaking from a pit near a reactor into the ocean, which may partially explain the high levels of radioactivity that have been found in seawater off the coast.
Tokyo Electric Power Co. said it had detected an 8-inch crack in the concrete pit holding power cables near reactor No. 2 and was working to seal the fracture. Tepco said the water was coming directly from the reactor and the radiation level was 1,000 millisieverts an hour. The annual limit of radiation exposure allowed for Fukushima workers is 250 millisieverts.
Workers pumped cement into the shaft Saturday, but by the end of the day, the flow of water into the ocean had not diminished. Engineers speculated that the water was preventing the cement from setting, allowing it to be washed away. Tepco officials said that on Sunday morning they would explore using a polymer — a type of quick-setting plastic — in an attempt to plug the leak.
After spraying thousands of tons of water on the reactors at Fukushima over the last three weeks to keep the facility from overheating and releasing dangerous amounts of radiation over a wide area, the utility is faced with the problem of great volumes of contaminated water.
With storage tanks at the facility nearing capacity, Tepco is contemplating storing the water in a giant artificial floating island offshore, Kyodo news reported. Tepco, which has been monitoring radiation levels in seawater just offshore from the plant, said it would begin sampling about nine miles off the coast.
Workers also have been spraying the grounds of the plant with a polymer in an attempt to prevent any radioactive isotopes that have been deposited there from escaping from the vicinity of the plant. The polymer acts like a kind of super-glue, binding any contaminants to the soil so they cannot be blown away.
As 25,000 Japanese and U.S. forces continued an intensive search for corpses along the tsunami-battered coastline of northern Japan, the official death toll climbed to 11,938 and the number of missing fell to 15,748, the National Police Agency said.
The number of people still taking refuge in emergency shelters has declined to about 165,000 from more than 200,000 in the days
immediately after the massive earthquake and tsunami March 11. But concerns are growing about the health of elderly evacuees at the shelters, some of which still lack enough kerosene to run heaters round-the-clock. Many areas of northern Japan are still experiencing subfreezing temperatures.
An NHK broadcast Saturday detailed the deaths of some elderly evacuees and cataloged harsh conditions facing aged survivors of the disaster, including crowded quarters, interruptions in the normal regimens of medicine and a discontinuation of services such as physical therapy.
In a bit of good news, NHK reported that coast guard officers had found a dog on the roof of a house floating in waters off Miyagi prefecture. The dog, which apparently had been stranded for three weeks, was emaciated and gobbled down sausages and cookies after being saved.
(Times staff writer Thomas H. Maugh II contributed to this story from Los Angeles.)