TOKYO — The operator of the stricken Fukushima Dai-ichi 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.
While the death toll continues to climb, thousands remain missing and tens of thousands are in shelters, the leaks are the most disturbing issue facing Japan after the earthquake and tsunami of March 11.
Tokyo Electric Power Co. said it had detected an 8-inch crack in the concrete pit holding power cables near reactor No. 2. 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 this 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, the utility is faced with the problem of great volumes of contaminated water.
With storage tanks at the facility nearing capacity, Tepco is considering 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.
Meanwhile, Japan continued to receive aid from other countries, including a German-designed robot that can be used to remove debris and help repair the power plant; British radiation counters and gas masks, and 10,000 tons of gas and diesel fuel from China.
Nuclear workers killed: The massive tsunami that crippled the nuclear power plant also killed two workers there, the operator announced today, confirming the first deaths at the complex. The two workers — a 21-year-old and a 24-year-old — had been missing, but their bodies were discovered only last week, according to the announcement.