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Japan plant workers sending lesser of two evils into the sea

Try to make room for runoff even more radioactive

The search for bodies continued yesterday in Ishinomaki, prior to intensive large-scale cleanup in northeast Japan. The search for bodies continued yesterday in Ishinomaki, prior to intensive large-scale cleanup in northeast Japan. (Carlos Barria/ Reuters)
By Hiroko Tabuchi
New York Times / April 5, 2011

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TOKYO — Tokyo Electric Power Co. began dumping more than 11,000 tons of radioactive water into the Pacific Ocean from the Fukushima Daiichi nuclear plant yesterday, mostly to make room in storage containers for increasing amounts of far more contaminated runoff.

The water, most of it to be released over two days, contains about 100 times the legal limit of radiation, Tokyo Electric said. The more contaminated water has about 10,000 times the legal limit.

The effort is intended to help workers clearing radioactive water from the turbine buildings at the damaged reactors, making it less dangerous to reach some of the most crucial controls for their cooling systems, which were knocked out by the 9.0 magnitude earthquake and tsunami that struck northeast Japan on March 11.

But the pumping effort is not expected to halt, or even alter, the gushing leak from a large crack in a 6-foot-deep pit next to the seawater intake pipes near the No. 2 reactor. The leak, discovered Saturday, has been spewing an estimated 7 tons of highly radioactive water an hour directly into the ocean; attempts to trace and plug it have so far failed.

Tokyo Electric, the plant’s operator, has been pumping hundreds of tons of water into four of the plant’s six reactors to cool nuclear fuel in the cores of three reactors, and in spent-fuel storage pools of those four. But leaks whose source is unclear — from the reactor containment units themselves, or pipes, valves, or other connected units — have flooded areas of the plant, bringing new complications in the effort to stave off full meltdowns of the fuel.

Workers have been pumping the runoff into storage tanks, most urgently the highly radioactive water flooding the turbine building of the No. 2 reactor. But the storage system is now full and adding capacity will take time.

Tokyo Electric is sending tanks to the plant, though they may not arrive until mid-April, a company spokesman said. The company also plans to moor a giant artificial island off the coast to store contaminated water, though getting the island in place will take at least a week, he said.

The utility said it would dump about 4,800 tons of water a day for two days. An additional 1,500 tons will also be released from the No. 5 and No. 6 reactors, after runoff was found flooding parts of their turbine buildings.

The concern there is that the water could damage the backup diesel generators for the reactors’ cooling systems, said Yukio Edano, the chief Cabinet secretary. That water will be released 300 tons at a time over five days.

Edano said he had ordered the company to monitor the effects of radioactive materials in the water on sea life. Consuming seafood caught in the area every day for a year would result in the intake of about 0.6 millisieverts of radiation, or about a quarter of the average annual exposure to radiation in Japan, a company spokesman said at a news conference.

But marine biologists expressed concern. “We’re seeing the levels of radioactive materials in the water increase, which means this problem is going to continue to get worse and worse,’’ said Kenya Mizuguchi, Tokyo University professor emeritus of maritime science and technology.

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