Signs of the Times

For Battered Japan, a New Threat: Nuclear Meltdown

March 12, 2011

AP - Cooling systems failed at another nuclear reactor on Japan's devastated coast Sunday, hours after an explosion at a nearby unit made leaking radiation, or even outright meltdown, the central threat to the country following a catastrophic earthquake and tsunami.

The Japanese government said radiation emanating from the plant appeared to have decreased after Saturday's blast, which produced a cloud of white smoke that obscured the complex. But the danger was grave enough that officials pumped seawater into the reactor to avoid disaster and moved 170,000 people from the area.

Japan's nuclear safety agency then reported an emergency at another reactor unit, the third in the complex to have its cooling systems malfunction. To try to release pressure from the overheating reactor, authorities released steam that likely contained small amounts of radiation, the government said.

Japan dealt with the nuclear threat as it struggled to determine the scope of the earthquake, the most powerful in its recorded history, and the tsunami that ravaged its northeast Friday with breathtaking speed and power. The official count of the dead was 686, but the government said the figure could far exceed 1,000.

Teams searched for the missing along hundreds of miles (kilometers) of the Japanese coast, and thousands of hungry survivors huddled in darkened emergency centers that were cut off from rescuers and aid. At least a million households had gone without water since the quake struck. Large areas of the countryside were surrounded by water and unreachable.

The explosion at the nuclear plant, Fukushima Dai-ichi, 170 miles (274 kilometers) northeast of Tokyo, appeared to be a consequence of steps taken to prevent a meltdown after the quake and tsunami knocked out power to the plant, crippling the system used to cool fuel rods there.

The blast destroyed the building housing the reactor, but not the reactor itself, which is enveloped by stainless steel 6 inches (15 centimeters) thick.

Inside that superheated steel vessel, water being poured over the fuel rods to cool them formed hydrogen. When officials released some of the hydrogen gas to relieve pressure inside the reactor, the hydrogen apparently reacted with oxygen, either in the air or the cooling water, and caused the explosion.

"They are working furiously to find a solution to cool the core," said Mark Hibbs, a senior associate at the Nuclear Policy Program for the Carnegie Endowment for International Peace.

Nuclear agency officials said Japan was injecting seawater into the core — an indication, Hibbs said, of "how serious the problem is and how the Japanese had to resort to unusual and improvised solutions to cool the reactor core."

Officials declined to say what the temperature was inside the troubled reactor, Unit 1. At 2,200 degrees Fahrenheit (1,200 degrees Celsius), the zirconium casings of the fuel rods can react with the cooling water and create hydrogen. At 4,000 F (2,200 C), the uranium fuel pellets inside the rods start to melt, the beginning of a meltdown.

Chief Cabinet Secretary Yukio Edano said radiation around the plant had fallen, not risen, after the blast but did not offer an explanation. Virtually any increase in dispersed radiation can raise the risk of cancer, and authorities were planning to distribute iodine, which helps protect against thyroid cancer. Authorities ordered 210,000 people out of the area within 12 miles (20 kilometers) of the reactor.

It was the first time Japan had confronted the threat of a significant spread of radiation since the greatest nightmare in its history, a catastrophe exponentially worse: the 1945 atomic bombings of Hiroshima and Nagasaki by the United States, which resulted in more than 200,000 deaths from the explosions, fallout and radiation sickness.

Officials have said that radiation levels at Fukushima were elevated before the blast: At one point, the plant was releasing each hour the amount of radiation a person normally absorbs from the environment each year.

The Japanese utility that runs the plant said four workers suffered fractures and bruises and were being treated at a hospital. Nine residents of a town near the plant who later evacuated the area tested positive for radiation exposure, though officials said they showed no health problems.

As Japan entered its second night since the magnitude-8.9 quake, there were grim signs that the death toll could soar. One report said no one could find four whole trains. Others said 9,500 people in one coastal town were unaccounted for and that at least 200 bodies had washed ashore elsewhere.

The government said 642 people were missing and 1,426 injured.

Atsushi Ito, an official in Miyagi prefecture, among the worst-hit states, could not confirm the figures, noting that with so little access to the area, thousands of people in scores of towns could not yet be reached.

"Our estimates based on reported cases alone suggest that more than 1,000 people have lost their lives in the disaster," Edano said. "Unfortunately, the actual damage could far exceed that number considering the difficulty assessing the full extent of damage."

Japan, among the most technologically advanced countries in the world, is well-prepared for earthquakes. Its buildings are made to withstand strong jolts — even Friday's, the strongest in Japan since official records began in the late 1800s. The tsunami that followed was beyond human control.

With waves 23 feet (7 meters) high and the speed of a jumbo jet, it raced inland as far as six miles (10 kilometers), swallowing homes, cars, trees, people and anything else in its path.

"The tsunami was unbelievably fast," said Koichi Takairin, a 34-year-old truck driver who was inside his sturdy, four-ton rig when the wave hit the port town of Sendai. "Smaller cars were being swept around me. All I could do was sit in my truck."

His rig ruined, he joined the steady flow of survivors who walked along the road away from the sea and back into the city Saturday.

Smashed cars and small airplanes were jumbled against buildings near the local airport, several miles (kilometers) from the shore. Felled trees and wooden debris lay everywhere as rescue workers in boats nosed through murky waters and around flooded structures.

The tsunami set off warnings across the Pacific Ocean, and waves sent boats crashing into one another and demolished docks on the U.S. West Coast. In Crescent City, California, near the Oregon state line, one person was swept out to sea and had not been found Saturday.

In Japan early Sunday, firefighters had yet to contain a large blaze at the Cosmo Oil refinery in the city of Ichihara. Four million households remained without power. The Russian news agency RIA Novosti reported that Japan had asked for additional energy supplies from Russia.

Prime Minister Naoto Kan said 50,000 troops had joined the rescue and recovery efforts, helped by boats and helicopters. Dozens of countries offered to pitch in. President Barack Obama said one American aircraft carrier was already off Japan and a second on its way.

Aid had just begun to trickle into many areas. More than 215,000 people were living in 1,350 temporary shelters in five prefectures, the Japanese national police agency said.

"All we have to eat are biscuits and rice balls," said Noboru Uehara, 24, a delivery truck driver who was wrapped in a blanket against the cold at a shelter in Iwake. "I'm worried that we will run out of food."

The transport ministry said all highways from Tokyo leading to quake-stricken areas were closed, except for emergency vehicles. Mobile communications were spotty and calls to the devastated areas were going unanswered.

One hospital in Miyagi prefecture was seen surrounded by water, and the staff had painted "SOS," in English, on its rooftop and were waving white flags.

Around the nuclear plant, where 51,000 people had previously been urged to leave, others struggled to get away.

"Everyone wants to get out of the town. But the roads are terrible," said Reiko Takagi, a middle-aged woman, standing outside a taxi company. "It is too dangerous to go anywhere. But we are afraid that winds may change and bring radiation toward us."

Although the government played down fears of radiation leak, Japanese nuclear agency spokesman Shinji Kinjo acknowledged there were still fears of a meltdown — the collapse of a power plant's systems, rendering it unable regulate temperatures and keep the reactor fuel cool.

Yaroslov Shtrombakh, a Russian nuclear expert, said it was unlikely that the Japanese plant would suffer a meltdown like the one in 1986 at Chernobyl, when a reactor exploded and sent a cloud of radiation over much of Europe. That reactor, unlike the reactor at Fukushima, was not housed in a sealed container.

Japan Tries Using Seawater to Cool Damaged Reactor

March 12, 2011

Wall Street Journal - Japanese officials continued their battle to control dangerous reactor overheating in the nation's worst nuclear accident that followed Friday's earthquake, as they resorted to an unprecedented attempt to cool the reactor with seawater.

Top government officials assured the nation Saturday evening that an explosion that took place at one of the reactors at the Tokyo Electric Power Co.'s Fukushima Daiichi nuclear-power plant earlier in the day merely knocked down the walls of its external concrete building, and that the reactor and the containment structure surrounding it remained intact.

"The latest explosion wasn't of a kind that would come with a significant leakage of radiation," Yukio Edano, the chief cabinet secretary, said at a news conference. "It's our expectation that we can bring this nuclear-power plant under control, using this unprecedented step of filling the containment structure with seawater." Boric acid will also be added to the salt water to fight a possible elevation in nuclear reaction, Mr. Edano said.

The building housing the stricken reactor collapsed Saturday afternoon with smoke billowing out, and officials responded by expanding the evacuation perimeter to a 12-mile radius and saying they were preparing to stockpile iodine supplies "just in case."

Soon after the explosion, the radiation level outside the reactor became elevated to 1,015 microsievert—the equivalent of being exposed to the maximum allowable level for a full year in a single day. The level has since come down sharply. The explosion was caused by hydrogen leaking inside the containment structure from the reactor experiencing high vapor pressure, Mr. Edano said.

Three people waiting at a nearby high school campus at the time of the explosion were confirmed to have been exposed to radiation, NHK, the national broadcaster, reported. The exposure, it said, hasn't affected their physical conditions. Some 90 people also at the site then—all to be evacuated from the proximity to the troubled power plant—may also have been exposed, it said.

Earlier in the day, Tokyo Electric took emergency measures to avert a meltdown of a stricken nuclear-power plant hit by massive tsunami that followed Friday's earthquake in the northeast region of Tohoku. Those steps appeared to be bringing down the dangerous pressures that had built up in the container, a Tokyo Electric spokesman said. But he and the government officials wouldn't discuss in detail the progress they have made in lowering the temperature inside the reactor.

The plant is located 150 miles away from Tokyo.

Previously, the utility had said there was a risk of a meltdown in the core after the quake cut off power to pumps providing cooling water. That, in turn, could lead to heating of the core, the risk of a meltdown, and the release of radiation.

A portion of the reactor's fuel rods, which create heat through a nuclear reaction, had become exposed due to tsunami-related cooling-system failure, a Tokyo Electric spokesman said.

"The size of tsunami caused by the latest earthquake far exceeded what we had previously assumed," Prime Minister Naoto Kan said at a news conference Saturday evening. "We've had a backup system designed to kick in when a nuclear-power plant failed, but this time, there has been a problem with that system."

Loss of cooling water resulted in a near meltdown of the Three Mile Island reactor in Pennsylvania in 1979, the worst nuclear incident in U.S. history.

If coolant isn't restored, the result could be what is known as a meltdown—extreme heat can melt through the reactor vessel and result in a radioactive release. Reactors have containment domes to catch any release. But there is always the chance that an earthquake could create cracks or other breaches in that containment system.

The Japanese government on Friday declared an emergency at the plant and ordered the evacuation of tens of thousands of residents in the area. Officials steadily increased the evacuation perimeter Saturday, extending it to 12 miles Saturday evening. More than 100,000 people will be affected by the step.

An earthquake measuring magnitude-8.9 struck Japan's northeastern region of Tohoku Friday, accompanied by massive tsunami waves that have killed at least 1,000 people, NHK reported. The quake touched off tsunami warnings as far away as Hawaii and the U.S. pacific coast.

At Fukushima Daiichi, the three reactors that were operating when the earthquake struck shut down as they were designed to do, but pressure built up inside them due to malfunctioning of their cooling system.

On Saturday, Tokyo Electric said another nuclear-power plant nearby, Fukushima Daini, was experiencing rises of pressure inside its four reactors. A state of emergency was called and precautionary evacuations ordered. The government has ordered the utility to release "potentially radioactive vapor" from the reactors, but hasn't confirmed any elevated radiation around the plant.

The International Atomic Energy Agency said it is ready to provide assistance if requested. All other Japanese power companies operating nuclear-power plants said their facilities are operating normally.

Nuclear problems are particularly troubling in Japan, which has 56 nuclear reactors, providing about 20% of the nation's electricity. Eleven reactors shut down as a result of the earthquake, as well as dozens of conventional fossil-fired or hydroelectric plants, leaving millions of people without electricity.

To cope with a severe power shortage expected to result from reactor shutdowns, Tokyo Electric on Saturday asked industrial customers to close or reduce their operations to save electricity and ensure supplies to households, a spokesman said.

When nuclear plants lose grid power, emergency on-site generation is supposed to furnish backup power. But some diesel generators at the Fukushima Daiichi plant failed a short time later due to the damage from the tsunami that followed the earthquake. That forced the plant to resort to batteries to furnish electricity to critical instrumentation and controls for at least one of the reactors, experts said.

Reactors at the plant use a special cooling system, called the Reactor Core Isolation Cooling system, to take waste heat and run some critical systems. But experts said even that system and batteries wouldn't be able to furnish as much power as was needed, putting pressure on plant officials to quickly find additional sources of electricity.

Experts said that Tokyo Electric has improved its processes and communications since a July 2007 earthquake heavily damaged the Kashiwazaki-Kariwa nuclear plant, one of the world's largest. The entire plant was shut down for 21 months following that quake, and some reactors still aren't back in operation.

Tokyo Electric was criticized after the 2007 quake for secrecy concerning how it was responding to problems at the Kashiwazaki plant and for rejecting inspection and assistance offers from the IAEA, which is intended to create confidence in the way an emergency is handled.

The Kashiwazaki plant suffered from seismic activity, in the 2007 quake, that exceeded the level for which it was designed, calling into question seismic assumptions made by regulators and the plant operator. There was a radioactive release when water sloshed out of spent-fuel-cooling pools and spilled into the Sea of Japan.