Glenda Kwek
March 15, 2011 - 7:29AM
Fears of a meltdown at one of the troubled nuclear reactors in Japan have grown after officials said its fuel rods were "fully exposed", as the country grappled with a growing humanitarian and economic crisis after Friday's devastating earthquake and tsunami.
Air pressure inside the No.2 reactor at the Fukushima Daiichi plant, located 250 kilometres north of Tokyo, rose suddenly when the air flow gauge was accidentally turned off, its operator Tokyo Electric Power Company (TEPCO) said.
Total destruction ... debris and wrecked houses smoulder in Ofunato City after the tsunami. Photo: AFP
Cooling water was blocked from flowing into the reactor, leading to full exposure of the rods at about 11.00pm on Monday (1.00am AEDT on Tuesday). When the rods are exposed and temperatures rise within the containment vessel, the rods could lose their vertical shape and melt down.
"We are not optimistic but I think we can inject water once we can reopen the valve and lower air pressure," a TEPCO official told reporters.
Japan asks for help
Risk of meltdown ... smoke comes out of the Fukushima Daiichi nuclear plant.
Photo: AFP
The latest revelations came as Japan asked the International Atomic Energy Agency, the UN's nuclear watchdog, to send experts to help it deal with its reactor problems.
The country has been grappling with a nuclear emergency since the massive earthquake, revised to magnitude 9.0 by Japanese authorities, and tsunami battered its north-east coast.
All nuclear plants shut down automatically across the country as they are designed to do. But the loss of power and tsunami damage to back-up generators apparently crippled reactor cooling systems.
Explosions created by hydrogen blew apart the buildings housing the No.1 and No.3 reactors at the Fukushima Daiichi plant, but officials said they did not pierce the reactors' steel and concrete containment vessels.
Chief government spokesman Yukio Edano said yesterday that radiation around the Fukushima Daiichi plant was at a tolerable level for humans.
No food, water or heating
Millions of people faced a fourth night without water, food or heating in near-freezing temperatures.
On the coastline of Miyagi prefecture, which took the full force of the tsunami, a Japanese police official said 1000 bodies were found scattered across the coastline. Kyodo, the Japanese news agency, reported that 2000 bodies washed up on two shorelines in Miyagi.
In one town in a neighbouring prefecture, the crematorium was unable to handle the large number of bodies being brought in for funerals.
"We have already begun cremations, but we can only handle 18 bodies a day. We are overwhelmed and are asking other cites to help us deal with bodies. We only have one crematorium in town," Katsuhiko Abe, an official in Soma, told The Associated Press.
Humanitarian crisis
Friday's double tragedy has caused unimaginable deprivation for people of this industralised country - Asia's richest - which hasn't seen such hardship since World War II.
In many areas there is no running water, no power and four- to five-hour waits for gasoline. People are suppressing hunger with instant noodles or rice balls while dealing with the loss of loved ones and homes.
"People are surviving on little food and water. Things are simply not coming," said Hajime Sato, a government official in Iwate prefecture, one of the hardest hit.
Sato said deliveries of food and other supplies were just 10 per cent of what is needed. Body bags and coffins were running so short that the government may turn to foreign funeral homes for help, he said.
"We have requested funeral homes across the nation to send us many body bags and coffins. But we simply don't have enough," he said. "We just did not expect such a thing to happen. It's just overwhelming."
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Fuel rods 'fully exposed'
The fuel rods in reactor two at Fukushima nuclear power plant are again 'fully exposed', boosting fears of a meltdown.
Risk of Japan nuclear meltdown increases
05:12 AEST Tue Mar 15 2011
Thomas Maugh
The fuel rods at a third nuclear reactor at the Fukushima No.1 nuclear power plant have been fully exposed to air, allowing them to heat up and raising the risk of a meltdown, according to officials of the Tokyo Electric Power Co, which owns the plant.
Engineers had begun pumping seawater into the reactor at the facility, the third reactor to receive the last-ditch treatment, after the plant's emergency cooling system had failed and the fuel rods had been partially exposed to the air.
But apparently something went wrong and the injection of water failed.
Workers were scrambling to re-immerse the fuel assembly before more damage is done to the reactor core.
No one knows how much damage has been done to the fuel rods, either in this reactor, No.2, or in reactors No.1 and No.3, where engineers began pumping in seawater over the weekend.
Officials have called the situation a partial meltdown because they have detected minute quantities of radioactive caesium and iodine - byproducts of the nuclear fission that powers the reactor - outside the plant.
That may mean simply that the zirconium cladding that sheathes the uranium fuel pellets has cracked due to heat from being exposed to the air, allowing small quantities of the radionuclides to escape, or it may mean that the fuel pellets themselves have partially melted.
As long as the reactor containment vessel remains intact, however, no one will know until workers can physically examine the fuel rods for damage.
Officials of the Tokyo Electric Power Co, which owns the plant, said conditions are stable at reactors No.1 and No.3 and that the cooling seems to be working.
An explosion at reactor No.3 on Sunday destroyed the outer building at the reactor and injured 11 workers, but did not damage the reactor containment vessel.
A similar explosion at reactor No.1 earlier in the weekend damaged that building and released what is said to be small amounts of radiation into the environment.
Three workers at the plant have been hospitalised for radiation exposure, but it is not clear how much radiation they received.
At least 20 civilians have had radiation detected on their clothes, but US experts believe their exposure was minimal.
A US warship sailing off the coast of Japan reported that it sailed through a small plume of radiation from the plant, but has successfully decontaminated both the ship and sailors.
Japanese authorities have so far reported no radiation release from the explosion at the No.3 reactor.
Authorities fear that the injection of seawater into the No.2 reactor and the exposure of the fuel rods to air could lead to a buildup of hydrogen gas and an explosion at that plant as well.
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