Fears mount as Japan takes desperate steps to cool reactors

UN nuclear watchdog chief says too early to say situation "out of control"; US stocks plunge on fears crisis will hit global growth; yen surges to all-time highs; Japan's emperor, in rare address, says deeply worried.

Japan tsunami devestation 311 (photo credit: REUTERS/US Navy)
Japan tsunami devestation 311
(photo credit: REUTERS/US Navy)
TOKYO - Operators of a quake-crippled nuclear plant in Japan again deployed military helicopters on Thursday in a bid to douse overheating reactors, as US officials warned of the rising risk of a catastrophic radiation leak from spent fuel rods.
While officials were scrambling to contain the nuclear crisis with a patchwork of fixes, the top US nuclear regulator warned that one reactor cooling pool for spent fuel rods may have run dry and another was leaking.
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"We believe that around the reactor site there are high levels of radiation," Gregory Jaczko, head of the Nuclear Regulatory Commission, told a House Energy and Commerce subcommittee hearing.
"It would be very difficult for emergency workers to get near the reactors. The doses they could experience would potentially be lethal doses in a very short period of time."
Health experts said panic over radiation leaks from the Daiichi plant was also diverting attention from other threats to survivors of last Friday's 9.0 magnitude earthquake and tsunami, such as the cold weather and access to fresh water.
The head of the world's nuclear watchdog, meanwhile, said it was not accurate to say things were "out of control" in Japan, but the situation was "very serious", with core damage to three units at the plant, around 240 kms (150 miles) north of Tokyo.
The latest images from the plant showed severe damage to some of the buildings after several blasts.
A stream of gloomy warnings and reports on the Japan crisis from experts and officials around the world triggered a swoon in global financial markets, with the Japanese yen surging to all-time highs against the dollar and all three major stock indexes slumping on fears of slower worldwide growth.
Japanese Finance Minister Yoshihiko Noda on Thursday blamed speculation for the yen's surge and repeated his warning that he would closely watch market action.
Japan's Nikkei average slumped on opening on Thursday, and an hour after opening was down nearly 4 percent.
G7 Finance ministers will hold a conference call later on Thursday to discuss steps to help Japan cope with the financial and economic impact of the disaster, a source said.
Japan's government said radiation levels outside the plant's gates were stable but, in a sign that it was overwhelmed, appealed to private companies to help deliver supplies to tens of thousands of people evacuated from around the complex.
"People would not be in immediate danger if they went outside with these levels. I want people to understand this," Chief Cabinet Secretary Yukio Edano told a news conference, referring to people living outside a 30-km (18-mile) exclusion zone.
Tokyo Electric Power Co. (TEPCO) officials said bulldozers attempted to clear a route to the reactor so firetrucks could gain access and try to cool the facility using hoses.
Company officials also said they had high hopes of getting limited power to the facility to help pump water needed to cool reactors and the spent fuel rods that have been overheating.
High radiation levels on Wednesday prevented a helicopter from dropping water into the No. 3 reactor to try to cool its fuel rods after an earlier explosion damaged the unit's roof and cooling system, but they managed on a second attempt on Thursday.
The plant operator described No. 3 -- the only reactor at that uses plutonium in its fuel mix -- as the "priority". Plutonium, once absorbed in the bloodstream, can linger for years in bone marrow or liver and lead to cancer.
Unprecedented crisis, emperor says
Japanese Emperor Akihito, delivering a rare video message to his people on Wednesday, said he was deeply worried by the crisis which was "unprecedented in scale".
"I hope from the bottom of my heart that the people will, hand in hand, treat each other with compassion and overcome these difficult times," the emperor said.
Panic over the economic impact of last Friday's massive earthquake and tsunami knocked $620 billion off Japan's stock market over the first two days of this week, but the Nikkei index rebounded on Wednesday to end up 5.68 percent.
The Tokyo Stock Exchange and the Financial Services Agency plan to keep the stock market open despite calls for a halt to trading, mainly from foreign financial institutions, the Nikkei business daily said.