- Associated Press - Tuesday, March 15, 2011

SOMA, Japan— A fire broke out at a nuclear reactor again Wednesday, a day after the power plant emitted a burst of radiation that panicked an already edgy Japan and left the government struggling to contain a spiraling crisis caused by last week’s earthquake and tsunami.

The outer housing of the containment vessel at the No. 4 unit at the Fukushima Dai-ichi nuclear complex erupted in flames early Wednesday, said Hajimi Motujuku, a spokesman for the plant’s operator, Tokyo Electric Power Co.

On Tuesday, a fire broke out in the reactor’s fuel storage pond — an area where used nuclear fuel is kept cool — causing radioactivity to be released into the atmosphere. Tokyo Electric Power said the new blaze erupted early Wednesday because the initial fire had not been fully extinguished. Firefighters were trying to put out the latest blaze.

Radiation levels in areas around the nuclear plant rose early Tuesday afternoon but appeared to subside by evening, officials said. But the unease remained in a country trying to recover from the massive disasters that are believed to have killed more than 10,000 people and battered the world’s third-largest economy.

The radiation leak caused the government to order 140,000 people living within 20 miles (30 kilometers) of the plant to seal themselves indoors to avoid exposure, and authorities declared a ban on commercial air traffic through the area. Worries about radiation rippled through Tokyo and other areas far beyond that cordon. The stock market plunged for a second day, dropping 10 percent.

A member of a British rescue team searches for victims in the tsunami-hit area in Ofunato, Iwate Prefecture, Japan, on Tuesday, March 15, 2011, four days after the disastrous earthquake and ensuing tsunami struck. (AP Photo/Itsuo Inouye)
A member of a British rescue team searches for victims in the ... more >

The troubles cascaded Tuesday at the Dai-ichi plant, where there have already been explosions at two reactor buildings since Friday’s disasters. An explosion at a third reactor blasted a 26-foot (8-meter) hole in the building and, experts said, damaged a vessel below the reactor, although not the reactor core. Three hours later, a fire broke out at a fourth reactor, which had been offline for maintenance.

In a nationally televised address Tuesday, Prime Minister Naoto Kan said radiation had seeped from four of the plant’s six reactors. The International Atomic Energy Agency said Japanese officials informed it that the fire was in a pool where used nuclear fuel rods are stored and that “radioactivity is being released directly into the atmosphere.” Long after the fire was extinguished, a Japanese official said the pool might still be boiling.

Depending on how bad the blast was at Unit 2, experts said more radioactive materials could seep out. If the water in the storage pond in Unit 4 boils away, the fuel rods could be exposed, leaking more virulent radiation.

Experts noted that much of the leaking radiation was apparently in steam from boiling water — and the falling radiation levels suggest the situation could be stabilizing.

Government spokesman Yukio Edano said the radiation leak potentially affected public health. But authorities and experts said the risks to the public diminished the farther the distance from the plant. At its most intense, the leak released a radioactive dose in one hour at the site 400 times the amount a person normally receives in a year. Within six hours, that level had dropped dramatically.

A person would have to be exposed to that dose for 10 hours for it to be fatal, said Jae Moo-sung, a nuclear engineering expert at Seoul’s Hanyang University.

Radiation elsewhere never reached that level. In Tokyo, 170 miles (270 kilometers) to the southwest, authorities reported radiation levels nine times normal — too small, officials said, to threaten the 39 million people in and around the capital. Weather patterns helped, shifting Tuesday night to the southeast, blowing any potential radiation from the plant toward the sea.

“It’s not good, but I don’t think it’s a disaster,” said Steve Crossley, an Australia-based radiation physicist. “If the radioactive material gets out, it’s a major problem. That doesn’t appear to be happening in Japan, and that’s the big difference. As long as you are not near it, it doesn’t pose a health risk.”

The IAEA said Tuesday that all other Japanese nuclear plants were in a safe and stable condition.

Though Kan and other officials urged calm, the developments fueled a growing panic in Japan and around the world amid widespread uncertainty over what would happen next. In the worst case scenario, one or more of the reactor cores would completely melt down, a disaster that could spew large amounts of radioactivity into the atmosphere.

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