Setback in Japan's reactor fight

Japan's nuclear crisis deepened as a fresh fire broke out in a quake-ravaged nuclear complex and expats fled Tokyo over warnings of radiation leaks. WSJ's Mariko Sanchanta and Yumiko Ono discuss.

REUTERS Snow falls Wednesday as rescue workers search a devastated factory area in Sendai, northern Japan.

TOKYO?Japan faced new setbacks in its struggle to tame a quake-ravaged nuclear complex as a fresh fire broke out there early Wednesday, workers were temporarily moved to safer locations, and new threats emerged in previously unaffected parts of the plant.

Radiation levels began rising sharply around 10 a.m. local time, according to a government spokesman, forcing outdoor workers at the power plant to move indoors, away from the most radioactive areas. But by 11:30 a.m. the workers were back on the job, the government's nuclear safety agency said.

It was the latest in a string of troubling turns at the Fukushima Daiichi nuclear power plant. Japan's nuclear safety agency said two workers are missing at the stricken plant's No. 4 reactor, the same one where the new fire had broken out. Wednesday morning's blaze was the second fire in the No. 4 reactor in consecutive days. That fire appeared to get extinguished. Later in the morning, white steam began billowing from the No. 3 reactor, raising the prospect of reactor damage and the potential release of radiation.

Separately, officials at the plant are weighing whether to use a helicopter to dump water into pools where radioactive waste is stored and cooled, in hopes of preventing the waste from igniting and releasing radioactivity.

The latest developments suggest that the disaster at facility is far from tamed. The plant has been emitting radiation for days, at levels that generally wouldn't cause an immediate health threat beyond the plant property, following severe damage from last week's quake and tsunami.

With the troubled reactors dominating the news, developments that might have seemed dramatic in calmer times drew only brief notice. Japan has been rocked by a stream of aftershocks since the big one Friday.

Two of the largest came Tuesday night and early Wednesday morning, crossing the 6.0 magnitude level. The epicenter for one was just 72 miles from Tokyo, and buildings in the city swayed steadily for an extended period of time. In nearby Shizuoka prefecture, more than 20,000 homes immediately lost power, 20 people were taken to the hospital, and one city hall office had ceilings collapse. But nobody was reported killed and no major damage was reported at the prefecture's Hamaoka nuclear plant.

At 8 a.m. Japan Standard Time, the National Police Agency reported that the new death total since Friday's quake and tsunami had reached 3,676. There were 7,558 confirmed missing, putting the combined tally past 10,000.

Japan's unfolding nuclear crisis could hamper assistance to quake victims if relief organizations withdraw to protect their workers. "The Japanese Red Cross Society is committed to rescue any victims, including those of nuclear radiation," JRCS spokesman Mutsuhiko Owaki said. "But we cannot send rescue workers to places where there is a clear risk of radiation exposure," he said, indicating that the group will have to limit its operations to areas where such risks are low. The group currently has about 500 doctors, nurses and other staff in hard-hit zones, including about 20 in Fukushima prefecture itself.

Until now, the focus of the crisis at the nuclear plant has been on its badly damaged nuclear reactors, which have been at risk of catastrophic overheating. Before the fires in the No. 4 reactor, officials had appeared to be gaining ground in their battle to cool down the reactors by pumping seawater into them.

But on Tuesday, officials were forced to turn their attention to the facility's waste-storage pools. These pools are used to warehouse spent fuel rods, which are no longer being used but remain highly radioactive and must also be cooled.

Officials say the water level that covers the rods plummeted in at least one of the storage pools, forcing them to inject new water. Temperatures were also rising in at least two other pools, requiring monitoring, according to the Japanese Government Emergency Headquarters. It is critical that the spent fuel rods remain covered in water, otherwise they can emit lethal doses of radioactivity.

At the fuel pool near reactor No. 4, where the water level at one point went to zero, the helicopter remains an option, officials say.

The concerns over the spent fuel pools are centered on reactors Nos. 4, 5, and 6?all of which were offline Friday when the mammoth quake hit Japan. But the situation at one of those offline reactors, No. 4, became dire on Tuesday when the spent fuel heated up and generated hydrogen that led to a fire, according to government officials.

That fire was extinguished in a few hours. But meantime, radiation levels at the plant's gate shot up to over 11,000 microsievert per hour. That level dropped back to below 600 (roughly equivalent to a medical X-ray) by midafternoon.

The currently reported Japanese radiation measurements are "well below" the U.S. Nuclear Regulatory Commission's dose limits of 10,000 microsieverts per nuclear event, according to an NRC statement. The annual occupational limit for workers who deal with radiation on the job is 50,000 microsieverts, according to an NRC spokesman.

Doctors have tested radiation levels in about 150 people from the close vicinity of the Fukushima Daiichi site. Authorities have taken measures to decontaminate 23 people, the IAEA says.

Officials were forced to evacuate all nonessential employees at the plant. The population was evacuated in a radius of 12 miles from the plant; residents in an 18 mile radius are asked to remain indoors; and an 18 mile no-fly zone has been established around the plant. The Japanese coast guard has banned shipping within six miles of the Fukushima Daiichi nuclear power plant and within two miles of the Fukushima Daini nuclear power plant.

"This is an accident that has not finished," IAEA Director General Yukiya Amano said.

Associated Press Members of Japan's Self-Defense Forces prepared for radioactive decontamination operations near a stricken nuclear facility Tuesday.

Until Tuesday, when fire broke out at the Fukushima Daiichi Plant's No. 4 reactor, officials had focused most of their efforts on trying to cool other reactors that had been operating when the quake struck. Electricity was cut to all three of those reactors?Nos. 1, 2, and 3?and officials pumped seawater into them to prevent radioactive material from melting.

Those efforts triggered chemical reactions that caused explosions in each of the reactor buildings. The International Atomic Energy Agency says Japan authorities believe the all-important "containment vessels" that encase the radioactive material in reactors 1 and 3 are intact. The state of the reactor 2 containment vessel is unclear.

The operator of the Fukushima Daiichi plant, Tokyo Electric Power Co., in 2009 told the government it had designed the facility against a radiation spill. According to that presentation, written in Japanese and posted on a government Web site, Tepco said safety measures would suspend operations at the reactors, cool them and shut them down with no danger of radiation escaping. "With even a large earthquake, the plant has been designed so that there will be no radiation impact in its vicinity," Tepco said in the presentation to the country's Nuclear Safety Commission.

By Wednesday, radiation at the nuclear plant had dropped significantly but concern about the spent fuel pools remained. Officials say temperatures in the pools at reactors 5 and 6 were rising Tuesday but that by early Wednesday, pumps were working and heating problems appeared to be resolved.

Six of seven pools are adjacent to the main reactors, in secondary containment structures that are not as robust as the containment structures that surround the reactors. They look somewhat like large swimming pools, but they are laced with boron, which gives them an irridescent blue hue. They are approximately 45 feet deep, so that the 15-foot fuel rods, which are vertically arranged in racks, have up to 30 feet of water on top of them to keep them cool.

If water boils or drains away, exposing the fuel rods, the metal cladding around the rods could begin to fail, in the process creating explosive hydrogen gas.

?Mitsuru Obe, Rebecca Smith, David Crawford and Ben Lefebvre contributed to this article.

Write to Yuka Hayashi at yuka.hayashi@wsj.com and Phred Dvorak at phred.dvorak@wsj.com

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