Japan fights to avert nuclear meltdown after quake

Estimated 10,000 people or more feared dead; officials work desperately to stop fuel rods in damaged reactors from overheating.

Japan Nuclear Radiation 311 (R) (photo credit: REUTERS)
Japan Nuclear Radiation 311 (R)
(photo credit: REUTERS)
FUKUSHIMA, Japan - Japan struggled on Monday to avert a nuclear disaster and care for millions of people without power or water, three days after an earthquake and tsunami killed an estimated 10,000 people or more in the nation's darkest hour since World War Two.
The world's third-largest economy opens for business later on Monday, a badly wounded nation that has seen whole villages and towns wiped off the map by a wall of water, leaving in its wake an international humanitarian effort of epic proportion.
RELATED:Japan: Working under assumption of a partial meltdownJapanese PM says country facing worst crisis since WWII
A grim-faced Prime Minister Naoto Kan described the crisis as Japan's worst since 1945, as officials confirmed that three nuclear reactors were at risk of overheating, raising fears of an uncontrolled radiation leak.
"The earthquake, tsunami and the nuclear incident have been the biggest crisis Japan has encountered in the 65 years since the end of World War II," Kan told a news conference.
"We're under scrutiny on whether we, the Japanese people, can overcome this crisis."
As he spoke, officials worked desperately to stop fuel rods in the damaged reactors from overheating. If they fail, the containers that house the core could melt, or even explode, releasing radioactive material into the atmosphere.
The most urgent crisis centers on the Fukushima Daiichi complex, where all three reactors are threatening to overheat, and where authorities say they have been forced to release radioactive steam into the air to relieve reactor pressure.
The complex, 240 km (150 miles) north of Tokyo, was rocked by an explosion on Saturday, which blew the roof off a reactor building. The government did not rule out further blasts there but said this would not necessarily damage the reactor vessels.
Authorities have poured sea water in all three of the complex's reactor to cool them down.
The complex, run by Tokyo Electric Power Co , is the biggest nuclear concern but not the only one: on Monday, the U.N. nuclear watchdog said Japanese authorities had notified it of an emergency at another plant further north, at Onagawa.
But Japan's nuclear safety agency denied problems at the Onagawa plant, run by Tohoku Electric Power Co , noting that radioactive releases from the Fukushima Daiichi complex had been detected at Onagawa, but that these were within safe levels at a tiny fraction of the radiation received in an x-ray.
Shortly later, a cooling-system problem was reported at another nuclear plant closer to Tokyo, in Ibaraki prefecture.
Fukushima's No. 1 reactor, where the roof was ripped off, is 40 years old and was originally set to go out of commission in February but had its operating license extended by 10 years.
Prime Minister Kan said the crisis was not another Chernobyl, referring to the nuclear disaster of 1986 in Soviet Ukraine.
"Radiation has been released in the air, but there are no reports that a large amount was released," Jiji news agency quoted him as saying. "This is fundamentally different from the Chernobyl accident."
Nevertheless, France recommended its citizens leave the Tokyo region, citing the risk of further earthquakes and uncertainty about the nuclear plants.
Broadcaster NHK, quoting a police official, said more than 10,000 people may have been killed as the wall of water triggered by Friday's 8.9-magnitude quake surged across the coastline, reducing whole towns to rubble.
Almost 2 million households were without power in the freezing north, the government said. There were about 1.4 million without running water. Kyodo news agency said about 300,000 people were evacuated nationwide.
Authorities have set up a 20-km (12-mile) exclusion zone around the Fukushima Daiichi plant and a 10 km (6 miles) zone around another nuclear facility close by.
The nuclear accident, the worst since Chernobyl, sparked criticism that authorities were ill-prepared for such a massive quake and the threat that could pose to the country's nuclear power industry.
Chief Cabinet Secretary Yukio Edano said there might have been a partial meltdown of the fuel rods at the No. 1 reactor at Fukushima. Engineers were pumping in seawater, trying to prevent the same happening at the No. 3 reactor, he said in apparent acknowledgement they had moved too slowly on Saturday.
"Unlike the No.1 reactor, we ventilated and injected water at an early stage," Edano told a news briefing.
The No. 3 reactor uses a mixed-oxide fuel which contains plutonium, but plant operator Tokyo Electric Power Co (TEPCO) said it did not present unusual problems.
TEPCO said radiation levels around the Fukushima Daiichi plant had risen above the safety limit but that it did not mean an "immediate threat" to human health.
The wind over the plant would continue blowing from the south, which could affect residents north of the facility, an official at Japan's Meteorological Agency said.