WRAPUP 3-Japan scrambles to avert nuclear disaster, global fears mount
* U.N nuclear watchdog chief says too early to say situation "out of control"
* U.S. stocks plunge on fears crisis will hit global growth
* Japan's emperor, in rare address, says deeply worried
* Second attempt to be made to use helicopters to dump water on plant (Adds details)
By Shinichi Saoshiro and Chisa Fujioka
TOKYO, March 17 (Reuters) - Operators of a quake-crippled nuclear plant in Japan said they would try again on Thursday to use military helicopters to douse overheating reactors, as U.S. officials warned of a rising risk of a catastrophic radiation leak from spent fuel rods.
Officials scrambled to contain the nuclear crisis with a variety of patchwork fixes. The top U.S. nuclear regulator warned that one reactor's cooling pool for spent fuel rods may have run dry and another was leaking.
"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 Friday's 9.0 magnitude quake and tsunami, such as the cold or 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 photographs 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 something of a meltdown in U.S. markets on Wednesday, with the Japanese yen surging to a record high against the dollar and all three major stock indexes slumping on fears of slower worldwide growth. European markets fared similarly.
Traders were glued to their screens, hitting the sell button every time officials gave ever bleaker assessments of the situation on the ground in Japan.
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.
www.reuters.com/article/2011/03/16/japan-quake-idUSL3E7EG2W20110316
March 17, 2011WRA