TOKYO, March 15 (Reuters): Japan faced a potential catastrophe on Tuesday after a quake-crippled nuclear power plant exploded and sent low levels of radiation floating toward Tokyo, prompting some people to flee the capital and others to stock up on essential supplies.
The crisis appeared to escalate late in the day when the operators of the facility said one of two blasts had blown a hole in the building housing a reactor, which meant spent nuclear fuel was exposed to the atmosphere.
Prime Minister Naoto Kan urged people within 30 km (18 miles) of the facility — a population of 140,000 — to remain indoors amid the world`s most serious nuclear accident since the Chernobyl disaster in Ukraine in 1986.
Officials in Tokyo — 240 km (150 miles) to the south of the plant — said radiation in the capital was 10 times normal by evening but posed no threat to human health in the sprawling high-tech city of 13 million people.
Toxicologist Lee Tin-lap at the Chinese University of Hong Kong said such a radiation level was not an immediate threat to people but the long-term consequences were unknown.
“You are still breathing this into your lungs, and there is passive absorption in the skin, eyes and mouth and we really do not know what long-term impact that would have,” Lee told Reuters by telephone.
Around eight hours after the explosions, the U.N. weather agency said winds were dispersing radioactive material over the Pacific Ocean, away from Japan and other Asian countries.
As concern about the crippling economic impact of the nuclear and earthquake disasters mounted, Japan`s Nikkei index fell as much as 14 percent before ending down 10.6 percent, compounding a slide of 6.2 percent the day before. The two-day fall has wiped some $620 billion off the market.
Authorities have spent days desperately trying to prevent the water which is designed to cool the radioactive cores of the reactors from running dry, overheating and emitting dangerous radioactive materials.
They said they may use helicopters to pour water on the most critical reactor, No. 4, within two or three days, but did not say why they would have to wait to do this.
“The possibility of further radioactive leakage is heightening,” a grim-faced Kan said in an address to the nation earlier in the day.
“We are making every effort to prevent the leak from spreading. I know that people are very worried but I would like to ask you to act calmly.”
Levels of 400 millisieverts per hour had been recorded near the No. 4 reactor, the government said. Exposure to over 100 millisieverts a year is a level which can lead to cancer, according to the World Nuclear Association.
The plant operator pulled out 750 workers, leaving just 50, and a 30-km (19 mile) no-fly zone was imposed around the reactors. There have been no detailed updates on what levels the radiation reached inside the exclusion zone where people live.
“Radioactive material will reach Tokyo but it is not harmful to human bodies because it will be dissipated by the time it gets to Tokyo,” said Koji Yamazaki, professor at Hokkaido University graduate school of environmental science. “If the wind gets stronger, it means the material flies faster but it will be even more dispersed in the air.”
A Reuters reporter using a Geiger counter showed negligible levels of radiation in the capital.
Despite pleas for calm, residents rushed to shops in Tokyo to stock up on supplies. Don Quixote, a multi-storey, 24-hour general store in Roppongi district, sold out of radios, flashlights, candles and sleeping bags.
