Water levels inside a quake-stricken Japanese nuclear reactor were almost empty on Monday night, said the power plant's operator, Tokyo Electric Power Co. TheYomiuri newspaper was reporting that the cooling system at the reactor has stopped, and additional reports said fuel rods were exposed. News agency Jiji said a meltdown of fuel rods inside the Fukushima Daiichi complex's No.2 reactor could not be ruled out.RELATED:US aircraft carrier reportedly sails into radioactive cloud2,000 bodies found on tsunami-stricken Japanese coastJapan: Working under assumption of a partial meltdownA meltdown raises the risk of damage to the reactor vessel and a possible radioactive leak, experts say.Earlier, a hydrogen blast at Japan's earthquake-stricken nuclear plant did not damage its primary containment vessel, the UN nuclear agency said.The International Atomic Energy Agency (IAEA) said it was told by Japanese nuclear authorities the control room of the unit No. 3 reactor at the Fukushima Daiichi nuclear plant remained operational, following Friday's massive earthquake and tsunami."The reactor building exploded but the primary containment vessel was not damaged. The control room of unit 3 remains operational," the IAEA said in a statement."All personnel at the site are accounted for. Six people have been injured," it said in a statement on its website.The core container of the No. 3 reactor was intact after the explosion, the government said, but it warned those still in the 20-kilometer (13-mile) evacuation zone to stay indoors.A Japanese official said before the blast 22 people had been confirmed to have suffered radiation contamination and up to 190 may have been exposed. Workers in protective clothing used hand-held scanners to check people arriving at evacuation centers.US warships and planes helping with relief efforts moved away from the coast temporarily because of low-level radiation. The US Seventh Fleet described the move as precautionary.US government officials told the NY Times that sailors and other military personnel on-board were exposed to a month's worth of radiation in an hour's time. They added that US helicopters flying humanitarian missions some 60 miles north of damaged Japanese reactors were coated with particulate radiation. The aircraft were washed off.The government had warned of a possible explosion at the No. 3 reactor because of the buildup of hydrogen in the building housing the reactor. TV images showed smoke rising from the Fukushima facility, 240 km (150 miles) north of Tokyo.
An explosion blew the roof off the No. 1 reactor building on Saturday.Officials confirmed on Sunday that three nuclear reactors north of Tokyo were at risk of overheating, raising fears of an uncontrolled radiation leak.Engineers worked desperately to cool the fuel rods. If they fail, the containers that house the core could melt, or even explode, releasing radioactive material into the atmosphere.