>Repair Work Resumes at Crippled Japanese Nuclear Plant

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Despite occasional sightings of smoke and steam billowing from damaged reactor buildings at the Fukushima-1 nuclear power plant in Japan, the effort has resumed to restore electricity and critical cooling functions. Radiation continues to be detected above normal

levels as far as 300 kilometers south of the facility, which was knocked out of commission by a huge quake and tsunami nearly two weeks ago.

After a break, because of concerns about smoke and radioactive steam, workers at the Fukushima-1 nuclear power plant on Thursday resumed the attempts to repair the cooling system at the Number 3 reactor.

That is the considered to be the most dangerous unit, because its fuel contains a mix of uranium and plutonium.

Video taken from a helicopter Thursday morning shows what appears to be steam rising from four of the nuclear facility’s six reactor buildings. However, authorities say the situation is not serious enough to continue a halt in the critical work to prevent a potentially larger catastrophe.

A re-emergence of black smoke at the Number 3 reactor halted work Wednesday.

There is also fresh concern about the damaged Number 1 reactor where pressure inside the reactor again increased.

Japan’s chief cabinet secretary Yukio Edano says crews are trying to maintain a delicate balance between spraying water on the radioactive fuel, which causes a rise in pressure, and reducing the water flow which could see temperatures increase to a dangerously high level.

Edano says experts are watching the situation closely and there is no evidence that the reactor vessel has been damaged by excessive pressure.

Since the March 11 magnitude 9.0 earthquake, which triggered a destructive tsunami, the nuclear power complex has experienced many serious problems. These include hydrogen explosions in reactor buildings, radiation leaks, exposed and overheating fuel rods, damaged reactor cores and shaking from powerful aftershocks.

Tokyo Electric Power Company, the plant operator, has also revealed that it spotted 13 times, between March 13 and 16th, a radioactive “neutron beam” about 1.5 kilometers from the Number 1 and 2 reactors.

Some scientists say this means uranium and plutonium might have leaked from the plant’s nuclear reactors and the exposed used nuclear fuel rods have discharged a small amount of neutron beams via fission.

James Symons, the director of the nuclear science division at the Lawrence Berkeley National Laboratory in California, expresses surprise and skepticism about the report.

“A neutron beam would be a beam of neutrons, which are a neutral particle. They are certainly produced in a fission reaction inside a reactor. But if neutrons escape and were to come out of the reactor they would not be visible. So you would not see a neutron beam,” he said. “Plus Ican’t imagine a process in which neutrons would be emitted from the reactor in a beam.”

The physicist says, at this stage, the Fukushima disaster has more in common with 1979 Three Mile Island partial meltdown, in the United States, than the 1986 Chernobyl catastrophe in Ukraine.

“All these things are different. But it’s closer,” said Symons. “It’s certainly very unlike what happened at Chernobyl where the entire reactor exploded basically. It’s certainly very serious, but – as far as we can tell – it’s also coming under control.”

Radiation continues to be detected in the surrounding air, soil and sea water.

Japan’s government is now advising people beyond the 30-kilometer exclusion zone around the Fukushima plant to remain indoors. Officials say that, since the explosions, some infants theoretically may have accumulated 100 millisieverts of radiation in their thyroids.

Some scientists say those exposed to that total radiation dose should take potassium iodide, because an annual dose of 100 millisieverts is believed to be associated with an increased risk of cancer.

Japan’s science ministry says radiation levels detected in Tokyo have tripled, compared to those detected earlier in the week.

The Tokyo metropolitan government, as well of those of the adjacent prefectures of Chiba and Saitama, have announced levels of radioactive iodine considered unsafe for infants were detected this week in tap water.

That has prompted panic buying of bottled water.

Vegetable shipments have been stopped out of areas adjacent to the crippled nuclear power plant after some leafy greens were found to be contaminated with radioactive iodine and cesium exceeding government standards.

>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.

>Japanese nuclear reactor in peril

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Japanese authorities and the U.S. military on Saturday were racing to find ways to deliver new backup generators or batteries to a nuclear power reactor whose cooling facilities have been crippled by a loss of power as a result of the earthquake.
The reactor, owned by Tokyo Electric Power Co., is currently drawing on battery power that may last only a few hours. Without electricity, the reactor will be unable to pump water to cool its hot reactor core, possibly leading to a meltdown or some other release of radioactive material.
Japanese authorities informed the International Atomic Energy Agency’s Incident and Emergency Center that they have ordered the evacuation of about 3,000 residents within a 1.9-mile radius of the Fukushima Daiichi nuclear power plant, and told people within a 16.2-mile radius to remain indoors, according to the IAEA Web site.
The cooling problem is with the second of six reactors at the plant, located on the east coast of Japan about 200 miles north of Tokyo and south of the heavily damaged town of Sendai. Separately there were reports of elevated radiation levels inside the control room of one of the other reactor units, which was built 40 years ago. Sources said that the authorities were contemplating venting from that unit.
Altogether, 11 Japanese nuclear reactors shut down automatically as they are designed to do in case of an earthquake.
“The multi-reactor Fukushima atomic power plant is now relying on battery power, which will only last around eight hours,” said Kevin Kamps, a specialist in nuclear waste at Beyond Nuclear, a group devoted to highlighting the perils of nuclear power. “The danger is the very thermally hot reactor cores at the plant must be continuously cooled for 24 to 48 hours. Without any electricity, the pumps won’t be able to pump water through the hot reactor cores to cool them.”
“There’s a basic cooling system that requires power, which they don’t have,” said Glenn McCullough, former chairman of the Tennessee Valley Authority who has been keeping track of the situation in Japan. He said that as a result of the tsunami, water had gotten into the diesel generators that would otherwise have provided backup power.
In a statement that confused nuclear experts, Secretary of State Hillary Rodham Clinton said Friday morning that U.S. Air Force planes in Japan had delivered “coolant” to a nuclear power plant affected by the quake. Nuclear reactors do not use special coolants, only large amounts of pumped water.
“They have very high engineering standards, but one of their plants came under a lot of stress with the earthquake and didn’t have enough coolant,” she said, “and so Air Force planes were able to deliver that.” It remained unclear what the Air Force had delivered.
Just hours after the quake, Japan’s Nuclear and Industrial Safety Agency (NISA) declared a heightened state of alert at the Fukushima Daiichi nuclear power plant, according to the IAEA. NISA said that no release of radiation has been detected.
The evacuation comes after NISA said Friday that a fire broke out at the Onagawa nuclear power plant but was later extinguished.
The plant is about 45 miles north of the city of Sendai, which was badly damaged by the deadly earthquake and tsunami that hit Japan Friday afternoon. Sendai is the population center nearest the epicenter of the quake, and Japan’s Kyodo News agency said that more than 200 bodies had been found so far near the city.
The key buildings in the Onagawa plant are about 15 meters above sea level, according to the Web site of Tohoku Electric Power, owner of the plant. The company said that was about twice the height of the previous highest tsunami.
Japanese authorities told the IAEA that that the Onagawa, Fukushima-Daini and Tokai nuclear power plants shut down automatically, and no radiation release has been detected. The plants have multiple nuclear reactors.
The IAEA said it is seeking details on Fukushima Daiichi and other nuclear power plants and research reactors, including information on off-site and on-site electrical power supplies, cooling systems and the condition of the reactor buildings. Nuclear fuel requires continued cooling even after a plant is shut down, the IAEA noted. “This is the most challenging seismic event on record, so it is a severe test,” said McCullough. “Clearly the Japanese government is taking this very seriously.”