Radiation spews into sky -- again...

By Shinichi Saoshiro and Chisa Fujioka

TOKYO | Tue Mar 15, 2011 10:47pm EDT

(Reuters) - Another fire broke out on Wednesday at an earthquake-crippled Japanese nuclear plant that has sent low levels of radiation wafting into Tokyo and triggered international alarm, suggesting that the crisis may be slipping out of control.

Academics and nuclear experts agree that the solutions being proposed to contain damage to the Daiichi reactors at Fukushima, 240 km (150 miles) north of Tokyo, are last-ditch efforts to stem what could well be remembered as one of the world's worst industrial disasters.

While public broadcaster NHK said flames were no longer visible at the building housing the No.4 reactor of the plant, Japanese TV pictures showed smoke rising from the facility at mid-morning (1000 local, 0100 GMT).

Experts say spent fuel rods in a cooling pool at the No. 4 reactor could be exposed by the fire and spew more radiation into the atmosphere. Operator Tokyo Electric Power said it was considering using a helicopter to dump boric acid, a fire retardant, on the facility.

Japan's Nuclear and Industrial Safety Agency said two workers were missing after blasts at the facility a day earlier blew a hole in the building housing the No. 4 reactor.

In the first hint of international frustration at the pace of updates from Japan, Yukiya Amano, director general of the International Atomic Energy Agency, said he wanted more timely and detailed information.

"We do not have all the details of the information so what we can do is limited," Amano told a news conference in Vienna. "I am trying to further improve the communication."

Several experts said that Japanese authorities were underplaying the severity of the incident, particular on a scale called INES used to rank nuclear incidents. The Japanese have so far rated the accident a four on a one-to-seven scale, but that rating was issued on Saturday and since then the situation has worsened dramatically.

"This is a slow-moving nightmare," said Dr Thomas Neff, a research affiliate at the Center for International Studies, which is part of the Massachusetts Institute of Technology. "This could be a five or a six -- it's premature to say since this event is not over yet."

France's nuclear safety authority ASN said Tuesday it should be classed as a level-six incident.

Japanese Prime Minister Naoto Kan on Tuesday urged people within 30 km (18 miles) of the facility -- a population of 140,000 -- to remain indoors, as authorities grappled with the world's most serious nuclear accident since the Chernobyl disaster in Ukraine in 1986.

Officials in Tokyo said radiation in the capital was 10 times normal at one point but not a threat to human health in the sprawling high-tech city of 13 million people.

The best advice experts could give them was to stay indoors, close the windows and avoid breathing bad air -- steps very similar to those for handling a smog alert or avoiding influenza.

While these steps may sound inconsequential, experts said the danger in Tokyo, while worrisome, is slight -- at least for now.

"Everything I've seen so far suggests there have been nominal amounts of material released. Therefore, the risks are generally low to the population," Jerrold Bushberg, who directs programs in health physics at the University of California at Davis, said in a telephone interview.