'Possible Meltdown' at Japan Nuke Plant

Photo by DigitalGlobe via Getty Images(TOKYO) -- It is "highly possible" that a partial meltdown was occurring in one of the nuclear reactors damaged in Friday's powerful earthquake, a Japanese government spokesman said Sunday, the most dire statement yet of the situation at the power plant.

Measures were taken at Unit 3 of the Fukushima Daiichi power plant, including releasing radioactive air and injecting sea water to reduce pressure and cool the reactor down, to prevent a possible meltdown, Chief Cabinet Secretary Yukio Edano said. But he also said it is "highly possible" there has been a partial meltdown in the unit.

The government had earlier denied that there was any possible meltdown.

In all, cooling systems have failed at six of the reactors at two Fukushima nuclear plants, including the reactor that exploded, where observers and experts have also feared a meltdown could occur.

The extent of the damage at the reactors and the cause of the explosion, which led Japanese officials to order tens of thousands to evacuate the region around the plant, are not clear.

According to Japan's Nuclear and Industrial Safety Agency -- an independent body -- the only thing that could have caused the explosion was a meltdown of the reactor core.

Along with the uncertainty about the nuclear facilities, Japan continues to be shaken by aftershocks from the 8.9 magnitude earthquake that hit Friday.

The official death toll from Friday's earthquake and tsunami rose to 763, while local media reports put fatality totals closer to 1,300 people. With thousands unaccounted for in the hardest hit areas, that number is expected to rise.

Speaking at a news conference Sunday, Japan Prime Minister Naoto Kan said he was confident that the country would get through the crisis "united," but acknowledged the scale of the disaster.

“In the 65 years after the end of World War II, this is the toughest, the most difficult crisis for Japan.”

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