Japan's prime minister, Naoto Kan, said Sunday that the earthquake and tsunami that had devastated much of northern Japan and raised the specter of nuclear meltdowns and release of radioactivity has confronted the nation with its most "severe crisis" since World War II.
"We Japanese people have overcome all kinds of hardships and were able to create a prosperous society," Kan said in an address televised nationwide. "In the face of the earthquake and tsunami we should be able to overcome these hardships, we believe we can overcome this."
However, he said, "The current situation of the earthquake, tsunami and the nuclear plants is in a way the most severe crisis in the past 65 years since World War II."
Officials predicted that the death toll in the prefecture of Miyagi, which is the state at the epicenter of the quake, would "certainly be more than 10,000," the Japanese network NHK reported
More than 300,000 people have been evacuated to emergency shelters, many of them residents in areas near stricken nuclear power plants, and millions of Japanese are confronted with food shortages, loss of power and other basic services.
The government has ordered 100,000 troops to engage in rescue and recovery efforts, the largest such mobilization since the last world war.
Two of the nuclear power plants whose cooling systems had failed in the wake of the quake may experience at least partial meltdowns and the same problems loomed over four others, according to the New York Times
While the magnitude of the situation at the nuclear plants has been likened to the Chernobyl disaster
in Russia 25 years ago, where the plant's nuclear core was exposed and radioactive fallout spread over a wide area, the Times said
Japanese nuclear safety officials and other experts believe that the release of radiation likely would be much smaller because of design differences in the plants.
At the plant where the situation was most dire – the Fukushima Daiichi Nuclear Power Station which is about 170 miles north of Tokyo – officials sought to deal with the breakdown of cooling systems by flooding a reactor with seawater.
The cooling also failed at a second reactor at the plant, raising the specter that nuclear melting was occurring there too and posed the danger of another explosion at the facility such as the one that occurred Saturday.
"The possibility that hydrogen is building up in the upper parts of the reactor building cannot be denied," said Yukio Edano, the government's chief cabinet secretary. "There is a possibility of a hydrogen explosion."
But he said the steel containment structure at the plant was "designed to withstand shocks."
"If measures can be taken, we will be able to ensure the safety of the reactor," Edano said.
"We're in a key period now," nuclear expert Joe Cirincione said on "Fox News Sunday." "The next 12 to 24 hours will tell us whether the Japanese officials will be able to get control back over these reactors, or it's gone, it's lost. The pumping of the seawater into reactor number one is that last ditch effort to try to stop it before it's too late. If they can succeed, if they can hold it for the next 24 hours or, so then these reactor cores will cool down and will be implied path to containing this disaster."
Cirincione said that if the danger at the Japan reactors were "to stop right now" it would rank lower on the scale of nuclear accidents," a local event without significant injury." He said, "if it continues, it will certainly get to ... the Three Mile Island category
of a serious event. We almost lost Three Mile Island and almost went meltdown. It stopped at the last minute. That is the situation we're fighting to maintain in Japan. If there is a meltdown, that puts it in a ... Chernobyl category -- a serious nuclear incident with potential for large scale loss of life."