Japan Nuclear Plant Is Far From Stable: U.S. Report

April 6, 2011— -- After workers successfully plugged the highly radioactive leak seeping into the Pacific Ocean, a new confidential assessment by the Nuclear Regulatory Commission obtained by the New York Times suggests that the damaged Fukushima Daiichi plant is far from stable.

Fragments of incredibly dangerous nuclear fuel were blown out of the reactors "up to one mile from the units," and then simply bulldozed over to protect workers on site, according to the NRC report.

Until now, flooding the damaged reactors with water has been considered the most efficient cooling method but the latest assessment raises concerns that the water may have introduced a new set of dangerous complications. U.S. engineers now worry that the enormous amount of water is actually weakening the containment vessels, making them more vulnerable to possible ruptures.

In an effort to avoid the continued spread of radiation and worse, a hydrogen explosion due to the hydrogen and oxygen present in seawater, plant operator TEPCO announced that it will begin injecting nitrogen into reactor one and likely reactors two and three. Nitrogen is normally present inside the containment that surrounds the reactor core and can prevent highly combustible hydrogen from exploding as it did three times in the early days after the March 11 disaster.

The Associated Press reports that Japan's Nuclear and Industrial Safety Agency (NISA) made clear that TEPCO is erring on the safe side. "The nitrogen injection is being considered a precaution," said NISA spokesman Hidehiko Nishiyama.

ABC News consultant and president of Ploughshares Fund, Joe Cirincione told ABC News that a hydrogen explosion, while not expected, is not totally out of the question.

"A new hydrogen explosion could happen, there could be a failure 'in one of' the fuel ponds that could cause a fire and if so, it could be a major release of radiation," said Cirincione.