>Workers scramble to cool reactors; official says 2nd blast possible

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Japanese efforts to prevent a nuclear meltdown by flooding reactors with seawater are a last-ditch attempt, but do not mean that a nuclear tragedy is imminent, experts said Sunday.
Nuclear experts who have followed the developments at the damaged Fukushima Daiichi nuclear plant in northeastern Japan say that despite several setbacks, the possibility of massive radiation exposure remains low — at least for now.
Meanwhile, a state of emergency has been declared at a nuclear power plant in Onagawa, Japan, where excessive radiation levels have been recorded following Friday’s massive earthquake, the United Nations’ atomic watchdog agency said Sunday.
Authorities have told the agency that the three reactor units at the Onagawa plant “are under control.”
“I don’t think we’re really close to a meltdown,” said Dale Klein, vice chancellor for special engineering projects at the University of Texas, referring to the Daiichi plant.
There does appear to be some fuel damage to one of the reactors, but the seawater method to keep them cool seems to be working.
“I think when the dust all settles, the death toll from the tsunami and the earthquake will be much more significant than any damage from these reactors,” he said.
The use of seawater shows that authorities are giving up future use of the Daiichi plant and are focusing solely on protecting people and the environment, experts said.
“If they are (using seawater), it’s because they have no other choice,” said James Walsh, a research associate at the security studies program at MIT. “The last thing you want to do is pump seawater and boron into a reactor.”
The salt and boron will corrode the reactor, he said.
“Essentially, they are saving the white flag and saying, ‘This plant is done,’ ” Walsh said. “This is a last-ditch mechanism to try to prevent overheating and to prevent a partial or full meltdown.”
In addition, danger from any radiation that escapes would vary on a number of factors, including the type of radiation, the amount and geography, he said.
The use of the seawater reflects the seriousness of the damage, said James Acton of the nuclear policy program at The Carnegie Endowment.
“You’re only going to do that if you’re seriously worried about the possibility of significant core meltdown,” he said.
He added that the word “meltdown” can mean a lot of different things, depending on its severity.
“So there’s both significant uncertainty about what’s going on at the moment, and significant uncertainty about the possible outcomes,” Acton said.
A major explosion of a reactor at the Daiichi plant is “almost inconcievable,” he said. “I think that worst-case outcome is unbelievably unlikely in this case.”
At the Daiichi nuclear plant, workers have been scrambling to cool off fuel rods at both reactors after the massive earthquake and tsunami disabled their cooling systems. Japanese authorities have said there is a “possibility” that a meltdown has occurred in the reactors.
A meltdown is a catastrophic failure of the reactor core, with a potential for widespread radiation release.
But Japanese officials stressed that there were no indications of dangerously high radiation levels in the atmosphere around the two reactors at the Fukushima Daiichi nuclear plant in northeastern Japan. They said they were unable to confirm whether a meltdown had occurred because they cannot get close enough to the reactors’ cores.
“We are continuing to monitor the radiation, but it is under control,” Edano told reporters.
Later Sunday, a spokesman for Japan’s prime minister repeated that assertion and said he would not describe what was occurring in the reactors as a “meltdown.”
“The situation is under control. ….We have been succeeding in lowering pressure inside the containment vessel,” spokesman Noriyuki Shikata said.
The aftermath of the devastating earthquake — from the scores of casualties to the nuclear concerns at the plant in Fukushima prefecture — marks the “toughest and most difficult crisis for Japan” since the end of World War II, Japanese Prime Minister Naoto Kan said Sunday.
Chief Cabinet Secretary Yukio Edano said an explosion could take place in the building housing the No. 3 reactor at the Daiichi plant.
“There is a possibility that the third reactor may have hydrogen gas that is accumulating in the reactor (that) may potentially cause an explosion,” he said.
An explosion caused by hydrogen buildup Saturday blew the roof off a concrete building housing the plant’s No. 1 reactor, but the reactor and its containment system were not damaged in the explosion.
Edano said the No. 3 reactor would also likely withstand a similar blast, noting that workers had already released gas from the building to try to prevent an explosion.
Meanwhile, the prime minister ordered a Tokyo power company to conduct a widespread power outage in an effort to preserve energy as workers try to repair power plants damaged in the earthquake, including nuclear facilities.
The Tokyo Electric Power Company has been instructed to conduct three-hour rolling blackouts as the country faces a 10 million kilowatt shortage, officials said.
Edano said doctors were examining nine people who tested positive for high radiation levels on their skin and clothing.
Meanwhile, he said authorities were responding under the presumption that meltdowns had taken place in both reactors.
If the effort to cool the nuclear fuel inside the reactor fails completely — a scenario experts who have spoken to CNN say is unlikely — the resulting release of radiation could cause enormous damage to the plant or release radiation into the atmosphere or water. That could lead to widespread cancer and other health problems, experts say.
Authorities have downplayed such a scenario, insisting the situation appears under control and that radiation levels in the air are not dangerous. Still, as what they described as “a precaution,” more than 200,000 people who live within 20 kilometers (12 miles) of the plant have been ordered to leave the area.
“The bottom line is that we just don’t know what’s going to happen in the next couple of days and, frankly, neither do the people who run the system,” added Dr. Ira Helfand, a member of the board of Physicians for Social Responsibility.
What we do know, he added, is that Japan’s nuclear facilities are “way out of whack.”
At one medical facility in Koriyama, about one hour from Fukushima, about 1 in 5 people being tested for high radiation levels are being referred to a hospital for further testing. About 1,000 people have been tested so far, officials said.
While some analysts said Japanese officials had not informed the public quickly enough about the evolving crisis, Jay Lehr, science director at the Heartland Institute in Chicago, said he was “100% confident” that Japan would be able to solve the problems at its nuclear plants.
“Nobody builds better power plants than Japan, because they are the most seismically active country on earth. They are built to withstand this very earthquake,” he said.
“I am absolutely, 100% confident that they will be able to solve the existing problem of a meltdown, if it is occurring, that they will be able to totally eliminate the escape of any radiation,” he said.
Robert Apthorpe, a nuclear engineer who has been fielding questions about Japan’s nuclear plant problems on Twitter, said Sunday that time is of the essence.
“We have to watch very carefully the next 24 to 48 hours. … We’re not out of the woods yet,” he said.
The problems at the Daiichi plant began Friday, when the 8.9-magnitude quake that struck offshore forced the automatic shutdown of the plant’s nuclear reactors and knocked out the main cooling system, according to the country’s nuclear agency.
A tsunami resulting from the quake then washed over the site, knocking out backup generators.
The reactors at the Daiichi plant are boiling-water reactors. The reactor affected by Saturday’s explosion is Fukushima Daiichi 1. It was connected to the grid in November 1970, making it about 40 years old.
The No. 1 unit is the oldest of six reactors at the Fukushima Daiichi site, according to the World Nuclear Association.
Japan is heavily dependent on nuclear power, with 54 plants and another eight slated for construction, said Aileen Mioko Smith of Green Action, an environmental group. All are located in “very seismic” areas, she said.
Authorities have also detected cooling system problems at another nuclear facility in Fukushima Prefecture, the Fukushima Daini plant, but have not expressed any concerns about possible meltdowns there.
Edano said that there have not been any leaks of radioactive material at either of the affected plants. Authorities deliberately have let out radioactive steam in order to alleviate growing pressure inside both of the affected reactors.