Grim Assessment of Japan Nuclear Plant Crisis by Top U.S. Nuclear Official NY Times

A top U.S. expert in nuclear matters has offered a grim assessment of the Japan nuclear plant crisis, reports The New York Times.

The official in question is Gregory Jaczko, the chairman of the United States Nuclear Regulatory Commission. He testified before Congress on Wednesday, March 16, 2011, about the crisis.

According to the article, "Mr. Jaczko (pronounced YAZZ-koe) said radiation levels might make it impossible to continue what he called the “backup backup” cooling functions that have so far helped check the fuel melting inside the reactors. Those efforts consist of using fire hoses to dump water on overheated fuel and then letting the radioactive steam vent into the atmosphere.

"Those emergency measures, carried out by a small squad of workers and firefighters, represent Japan’s central effort to forestall a full-blown fuel meltdown that would lead to much higher releases of radioactive material into the air.

"Mr. Jaczko’s testimony, the most extended comments by a senior American official on Japan’s nuclear disaster, described what amounts to an agonizing choice for Japanese authorities: keep sending workers into an increasingly contaminated area in a last-ditch effort to cover nuclear fuel with water, or do more to protect the workers but risk letting the pools boil away — and thus risk a broader meltdown."

The article adds, "On Wednesday, the American Embassy in Tokyo, on advice from the Nuclear Regulatory Commission, told Americans to evacuate a radius of “approximately 50 miles” from the Fukushima plant. The advice to Americans in Japan represents a graver assessment of the risk in the immediate vicinity of Daiichi than the warnings made by the Japanese themselves, who have told everyone within 20 kilometers, about 12 miles, to evacuate, and those within about 20 miles to take shelter."

The story also notes, "While maps of the plume of radiation being given off by the plant show that an elongated cloud will stretch across the Pacific, American officials said it would be so dissipated by the time it reached the West Coast of the United States that it would not pose a health threat.

"According to a Swedish government researcher, Lars-Erik De Geer, , low concentrations of radioactive particles are heading eastward from the power plant toward North America, but not at levels dangerous for humans, Reuters reported. He was citing data from a network of international monitoring stations."