The day after Japan’s giant earthquake has been a scary one for many of us in Japan. At 8:45p.m. Saturday evening (6:45 a.m. EST), Japan breathed a collective sigh of relief, at least for now. The government announced that the explosion at an
earthquake-damaged nuclear plant is not causing radiation to leak, as had been widely feared and suspected.
The explosion occurred about 3:30 p.m. local time Saturday at a plant in Fukushima, some 100 kilometers north of Tokyo. In its aftermath, the government had been avoiding mention of how much radiation was leaking and how large an area might be affected. Instead it ordered the evacuation of those who are living within 10 kilometers of the plant, and then expand the range to 20 kilometers.
Prior to the evening announcement, there had been no information released by either the Japanese government or Tokyo Electric Power. Co., which owns and operates the nuclear plant. Meanwhile, nuclear experts from the private sector appeared on TV yelling “Don’t go out! Keep windows closed and stay at home!” It was unclear whether their advice was directed to people in Fukushima or those in a far wider area, including Tokyo with its population of 13 million.
I live in Tokyo and to be cautious I did not allow my nine year-old daughter to go outside. Now, it appears like a worst-case scenario might be avoided. But that does not ease the pain of this country.
There is so much we don’t know yet. The
tsunami that followed the earthquake hit several hundred kilometers of coastline. Officially, the death toll so far is limited to 1,000 to 1,500 people nationwide. But according to the latest reports, in the Miyagi Prefecture town of Minami-Sanriku alone, some 10,000 people are missing.
The number represents more than half of the town’s entire population. I’m sure there are a number of towns like Minami-Sanriku in the region. The death toll could easily reach five digits, and maybe six.
A photographer friend of mine called me at 10 p.m. from Chiba, a Tokyo suburb. He’d left Tokyo in early evening, heading north to shoot the aftermath of the quake, but his car got stuck in traffic before he’d gotten anywhere near the epicenter of the damage in the Sendai region. It looks unlikely that he’ll make it to his destination by morning.
My friend asked me if I’m still planning to go to the Middle East to cover the unfolding revolutions there, as I’d planned prior to the earthquake. I told him my plans were still on. I’d been with him in Iraq during the war there. I’ve been debating all day long whether I should go or not, given the devestation in my homeland. It’s a tough decision to make, not as a journalist but as a Japanese citizen. All my friend could say was “Good luck.”
The
Institute for Public Accuracy issued the following statement by nuclear expert,
Kevin Kamp, about the risk of nuclear disaster in post-Earthquake Japan: “The electrical grid is down. The emergency diesel generators have been damaged. The multi-reactor Fukushima atomic power plant is now relying on battery power, which will only last around eight hours. 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. Once electricity is lost, the irradiated nuclear fuel could begin to melt down. If the containment systems fail, a catastrophic radioactivity release to the environment could occur.”
“In addition to the reactor cores, the storage pool for highly radioactive irradiated nuclear fuel is also at risk. The pool cooling water must be continuously circulated. Without circulation, the still thermally hot irradiated nuclear fuel in the storage pools will begin to boil off the cooling water. Within a day or two, the pool’s water could completely boil away. Without cooling water, the irradiated nuclear fuel could spontaneously combust in an exothermic reaction. Since the storage pools are not located within containment, a catastrophic radioactivity release to the environment could occur. Up to 100 percent of the volatile radioactive Cesium-137 content of the pools could go up in flames and smoke, to blow downwind over large distances. Given the large quantity of irradiated nuclear fuel in the pool, the radioactivity release could be worse than the Chernobyl nuclear reactor catastrophe of 25 years ago.”
Kamps is a specialist in nuclear waste at
Beyond Nuclear and conducted research last year assessing the state of nuclear facilities in Japan.
Meanwhile, Japan has ordered thousands of residents near a northeastern nuclear power plant to evacuate today following a massive earthquake that caused a problem in the plant’s cooling system, according to the Associated Press.
A ferocious tsunami unleashed by Japan’s biggest recorded earthquake slammed into its eastern coast Friday, killing hundreds of people as it carried away ships, cars and homes, and triggered widespread fires that burned out of control.
Hours later, the waves washed ashore on Hawaii and the U.S. West coast, where evacuations were ordered from California to Washington but little damage was reported. The entire Pacific had been put on alert — including coastal areas of South America, Canada and Alaska — but waves were not as bad as expected.
In northeastern Japan, the area around a nuclear power plant was evacuated after the reactor’s cooling system failed and pressure began building inside, as the government declared its first-ever state of emergency at a nuclear plant.
Police said 200 to 300 bodies were found in the northeastern coastal city of Sendai, the city in Miyagi prefecture, or state, closest to the epicenter. Another 151 were confirmed killed, with 547 missing. Police also said 798 people were injured.
The magnitude-8.9 offshore quake triggered a 23-foot (seven-meter) tsunami and was followed for hours by more than 50 aftershocks, many of them more than magnitude 6.0.
It shook dozens of cities and villages along a 1,300-mile (2,100-kilometer) stretch of coast, including Tokyo, hundreds of miles (kilometers) from the epicenter. A large section of Kesennuma, a town of 70,000 people in Miyagi, burned furiously into the night with no apparent hope of being extinguished, public broadcaster NHK said.
Scientists said the quake ranked as the fifth-largest earthquake in the world since 1900 and was nearly 8,000 times stronger than one that devastated Christchurch, New Zealand, last month.
“The energy radiated by this quake is nearly equal to one month’s worth of energy consumption” in the United States, U.S. Geological Survey Scientist Brian Atwater told The Associated Press.
President Barack Obama pledged U.S. assistance following what he called a potentially “catastrophic” disaster. He said one U.S. aircraft carrier is already in Japan, and a second is on its way. A U.S. ship was also heading to the Marianas Islands to assist as needed, he added.
As night fell and temperatures hovered just above freezing, tens of thousands of people remained stranded in Tokyo, where the rail network was still down. The streets were jammed with cars, buses and trucks trying to get out of the city.
The city set up 33 shelters in city hall, on university campuses and in government offices, but many planned to spend the night at 24-hour cafes, hotels and offices.
The government ordered about 3,000 residents near a nuclear power plant in the city of Onahama to move back at least two miles (three kilometers) from the plant. The reactor was not leaking radiation but its core remained hot even after a shutdown. The plant is 170 miles (270 kilometers) northeast of Tokyo.
Japan’s nuclear safety agency said pressure inside the reactor at the Fukushima No. 1 power plant has risen to 1.5 times the level considered normal, and slightly radioactive vapor may be released to reduce the pressure.
The Defense Ministry said it had sent dozens of troops trained to deal with chemical disasters to the plant in case of a radiation leak.
Trouble was reported at two other nuclear plants, but there was no radiation leak at either of them.
Japan’s Nikkei.com
is reporting that the explosion at the Fukushima No. 1 reactor was due to a meltdown of nuclear fuel rods in its insufficiently cooled core. This was consistent with reports of radioactive cesium and iodine outside the plant. As well as the suggestion that it was a build up of hydrogen gas inside the reactor that led to the explosion earlier in the day. (You can see video of that explosion
here.)
Others think the declaration of meltdown is
premature. Regardless, this is a very bad nuclear accident. Far worse that Three Mile Island, but not yet in the Chernobyl league.
In a statement this afternoon, former member of the U.S. Nuclear Regulatory Commission Peter Bradford said, “An early tipoff that Japanese authorities felt that events at Fukushima were very serious was the ordering of an evacuation within a couple of hours of the earthquake. Though the area was small and the evacuation was called ‘precautionary,’ the fact is that ordering several thousand more people into motion during the immediate aftermath of a major earthquake and tsunami is something that no government would do if it could possibly help it.”
Despite alarmist reports, it’s unlikely that the disaster will reach the level of Chernobyl because the Fukushima reactor has a steel containment structure surrounding the nuclear fuel, and it appears that at least for now the engineers will be able to cool the fuel by pumping seawater into the reactor.
The American Nuclear Society blog has a page
here with links to update sites operated by Tokyo Electric Power, the Nuclear Energy Institue and others.
World Nuclear News
reports that only three of the six Fukushima reactors were in operation when the earthquake hit.
Tokyo Electric Power Co. has said it plans to vent gas from the containment structures–reducing dangerous pressures, but releasing radiation into the air.
This could prevent a worse disaster, but is still highly dangerous, even if winds blow most of the radioactive material out to sea. In an email statement this afternoon, Ira Helfand, member of Physicians for Social Responsibility writes that, “After one year of operation, a commercial nuclear reactor contains 1000 times as much radioactivity as was released by the Hiroshima bomb. From a public health perspective, the most important isotopes are short-lived isotopes of iodine (like Iodine-131), Cesium-137, Strontium-90, and possibly Plutonium-239. Radioactive iodine caused thousands of cases of thyroid cancer in children after the Chernobyl accident. Cesium and strontium cause a number of different kinds of cancer and remain dangerous for hundreds of years; plutonium causes lung cancer as well as other types of cancer and remains deadly for hundreds of thousands of years.”
The anti-nuclear Nuclear Information & Resource Services
states that the type of reactor used at Fukushima has been known for years to have containment weaknesses.
With this situation still in flux, it’s hard to think too far ahead right now. But it’s absolutely clear that the loss of so much nuclear power generation across Japan will result in a
big uptick in demand for liquified natural gas imports.
Rebuilding reactors could be a boon for the likes of
General Electric (which designed the Fukushima reactor) as well as French nuclear giant Areva. This should also be an opportunity for Westinghouse, which has designed the
third-generation AP1000 reactor to shut down safely even in the event of complete loss of electric power.
Japan's nuclear safety agency is reporting an emergency at a second reactor in the same complex where an explosion had occurred earlier. The Nuclear and Industrial Safety Agency said early Sunday that the cooling system malfunctioned at Unit 3 of the Fukushima Dai-ichi nuclear plant. The agency said it was informed of the emergency by Tokyo Electric, the utility which runs the plant.
No further details of the troubles at Unit 3 were immediately available.
An explosion occurred at another reactor in the complex on Saturday, destroying the building housing the reactor and handing authorities an urgent complication amid rescue and relief efforts a day after Friday's earthquake and tsunami devastated Japan's northeastern coast.
THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.
IWAKI, Japan (AP) — An explosion at a nuclear power plant on Japan's devastated coast destroyed a building Saturday and made leaking radiation, or even outright meltdown, the central threat menacing a nation just beginning to grasp the scale of a catastrophic earthquake and tsunami.
The Japanese government said radiation emanating from the plant appeared to have decreased after the 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 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 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.
AP/Kyodo News The explosion at the nuclear plant, Fukushima Dai-ichi, 170 miles 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 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 รข€” 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, the zirconium casings of the fuel rods can react with the cooling water and create hydrogen. At 4,000 degrees, 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 moved 170,000 people out of the area within 12 miles of the reactor, said the Vienna-based International Atomic Energy Agency, citing information from Japanese officials.
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.
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 high and the speed of a jumbo jet, it raced inland as far as six miles, 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 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 docs on the U.S. West Coast. In Crescent City, Calif., 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.
___
Kageyama reported from Tokyo. Associated Press writers Malcolm J. Foster, Mari Yamaguchi, Tomoko A. Hosaka and Shino Yuasa in Tokyo, Jay Alabaster in Sendai, Sylvia Hui in London, David Nowak in Moscow, and Margie Mason in Hanoi also contributed.
Inside the troubled nuclear power plant, officials knew the risks were high when they decided to vent radioactive steam from a severely overheated reactor vessel. They knew a hydrogen explosion could occur, and it did. The decision still trumped the worst-case alternative — total nuclear meltdown.
At least for the time being.
The chain of events started Friday when a magnitude-8.9 earthquake and tsunami severed electricity to the Fukushima Dai-ichi nuclear complex 170 miles (270 kilometers) northeast of Tokyo, crippling its cooling system. Then, backup power did not kick in properly at one of its units.
From there, conditions steadily worsened, although government and nuclear officials initially said things were improving. Hours after the explosion, they contended that radiation leaks were reduced and that circumstances had gotten better at the 460-megawatt Unit 1. But crisis after crisis continued to develop or be revealed.
Without power, and without plant pipes and pumps that were destroyed in the explosion of the most-troubled reactor's containment building, authorities resorted to drawing seawater in an attempt to cool off the overheated uranium fuel rods.
Robert Alvarez, senior scholar at the Institute for Policy Studies and former senior policy adviser to the U.S. secretary of energy, said in a briefing for reporters that the seawater was a desperate measure.
"It's a Hail Mary pass," he said.
He said that the success of using seawater and boron to cool the reactor will depend on the volume and rate of their distribution. He said the dousing would need to continue nonstop for days.
Another key, he said, was the restoration of electrical power, so that normal cooling systems can be restored.
Officials placed Dai-ichi Unit 1, and four other reactors, under states of emergency Friday because operators had lost the ability to cool the reactors using usual procedures.
An additional reactor was added to the list early Sunday, for a total of six — three at the Dai-ichi complex and three at another nearby complex. Local evacuations have been ordered at each location. Japan has a total of 55 reactors spread across 17 complexes nationwide.
Officials began venting radioactive steam at Fukushima Dai-ichi's Unit 1 to relieve pressure inside the reactor vessel, which houses the overheated uranium fuel.
Concerns escalated dramatically Saturday when that unit's containment building exploded.
It turned out that officials were aware that the steam contained hydrogen, acknowledged Shinji Kinjo, spokesman for the government Nuclear and Industrial Safety Agency. More importantly, they also were aware they were risking an explosion by deciding to vent the steam.
The significance of the hydrogen began to come clear late Saturday:
_Officials decided to reduce rising pressure inside the reactor vessel, so they vented some of the steam buildup. They needed to do that to prevent the entire structure from exploding, and thus starting down the road to a meltdown.
_At the same time, in order to keep the reactor fuel cool, and also prevent a meltdown, operators needed to keep circulating more and more cool water on the fuel rods.
_Temperature in the reactor vessel apparently kept rising, heating the zirconium cladding that makes up the fuel rod casings. Once the zirconium reached 2,200 degrees Fahrenheit (1,200 Celsius), it reacted with the water, becoming zirconium oxide and hydrogen.
_When the hydrogen-filled steam was vented from the reactor vessel, the hydrogen reacted with oxygen, either in the air or water outside the vessel, and exploded.
A similar "hydrogen bubble" had concerned officials at the 1979 Three Mile Island nuclear disaster in Pennsylvania until it dissipated.
If the temperature inside the Fukushima reactor vessel continued to rise even more — to roughly 4,000 degrees Fahrenheit (2,200 Celsius) — then the uranium fuel pellets would start to melt.
According to experts interviewed by The Associated Press, any melted fuel would eat through the bottom of the reactor vessel. Next, it would eat through the floor of the already-damaged containment building. At that point, the uranium and dangerous byproducts would start escaping into the environment.
At some point in the process, the walls of the reactor vessel — 6 inches (15 centimeters) of stainless steel — would melt into a lava-like pile, slump into any remaining water on the floor, and potentially cause an explosion much bigger than the one caused by the hydrogen. Such an explosion would enhance the spread of radioactive contaminants.
If the reactor core became exposed to the external environment, officials would likely began pouring cement and sand over the entire facility, as was done at the 1986 Chernobyl nuclear accident in the Ukraine, Peter Bradford, a former commissioner of the U.S. Nuclear Regulatory Commission, said in a briefing for reporters.
At that point, Bradford added, "many first responders would die."
Japan's top government spokesman says a partial meltdown is likely under way at second reactor affected by Friday's massive earthquake.
Chief Cabinet Secretary Yukio Edano said Sunday that radiation at the nuclear power plant in Fukushima briefly rose above legal limits, but it has since declined significantly.
Three reactors at the plant lost their cooling functions in the aftermath of quake and tsunami because of a power outage.
Some 170,000 people have been ordered to evacuate the area within 12 miles (20 kilometers) of the plant.
The plant is 170 miles (270 kilometers) north of Tokyo.
THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.
IWAKI, Japan (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 763, 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. Some 2.5 million households were without electricity.
Powerful aftershocks continued to rock the country, including one Sunday with a magnitude of 6.2 that originated in the sea, about 111 miles (179 kilometers) east of Tokyo. It swayed buildings in the capital, but there were no reports of injuries or damage.
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 Fahrenheit (2,200 Celsius), 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.
Among those waiting to leave was Reiko Takagi, a middle-aged woman standing outside a taxi company in Iwaki, about 19 miles (30 kilometers) from the nuclear plant.
"Everyone wants to get out of the town. But the roads are terrible," Takagi said. "It is too dangerous to go anywhere. But we are afraid that winds may change and bring radiation toward us."
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.
Two days after 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 100,000 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.
Two other U.S. rescue teams of 72 personnel each and rescue dogs were scheduled to arrive later Sunday, as was a five-dog team from Singapore.
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.
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.
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Kageyama reported from Tokyo. Associated Press writers Malcolm J. Foster, Mari Yamaguchi, Tomoko A. Hosaka and Shino Yuasa in Tokyo, Jay Alabaster in Sendai, Sylvia Hui in London, David Nowak in Moscow, and Margie Mason in Hanoi also contributed.
Japan mobilised 50,000 military and other rescue personnel Saturday to spearhead a Herculean rescue and recovery effort, a day after being hit by its most devastating quake and tsunami on record.
Every wing of the Self Defence Forces was thrown into frantic service, with hundreds of ships, aircraft and vehicles headed to the Pacific coast area where at least 1,000 people were feared dead and entire neighbourhoods had vanished.
International search and rescue teams also rushed to the devastated country, some fresh from work in quake-hit New Zealand -- including a 63-strong Japanese team that spent two weeks helping after the 6.3-magnitude Christchurch quake.
As emergency staff in Japan dug through rubble and plucked survivors off the roofs of submerged houses, Prime Minister Naoto Kan warned that day one after the catastrophe was a crucial window for survivors.
"I realised the huge extent of the tsunami damage," the centre-left premier said after taking a helicopter tour of the apocalyptic scenes in the northeast before meeting his cabinet ministers for an emergency meeting in Tokyo.
"What used to be residential areas were mostly swept away in many coastal areas and fires are still blazing there," he told them.
The United States, with almost 50,000 troops stationed in Japan, ordered a flotilla including two aircraft carriers to the region to provide aid -- just one of scores of nations that have offered help since Friday's monster quake.
US forces on Friday helped Japan rapidly react by delivering a cooling agent to a nuclear plant where malfunctions threatened a dangerous meltdown.
In the utter bleakness on the east coast of Japan's main Honshu island, where at least 3,600 houses were destroyed by the 8.9-magnitude quake, there were some rays of hope amid the carnage of smashed towns and shattered lives.
Army helicopters airlifted people off the roof of an elementary school in Watari, Miyagi prefecture, and naval and coastguard choppers did the same to rescue 81 people from a ship that had been hurled out to sea by the tsunami.
But for every piece of good news, there were more reminders of nature's cruelty against this seismically unstable nation -- including the latest of a series of strong aftershocks in the morning, measuring a hefty 6.8.
In large coastal areas, entire neighbourhoods were destroyed, with unknown numbers of victims buried in the rubble of their homes or lost to the sea, where cars, shipping containers, debris and entire houses were afloat.
The coastal city of Rikuzentakata in Iwate prefecture was almost completely destroyed and submerged, said the Fire and Disaster Management Agency.
Some 300-400 bodies were recovered in the city of 23,000 people, NHK quoted the military as saying, while police reportedly said 200-300 bodies had been found in the city of Sendai.
In the quake-hit areas, 5.6 million households had no power Saturday and more than one million households were without water.
Japan's military started its mass deployment Friday, when it dispatched 300 planes and an armada of 20 naval destroyers and other ships, while some 25 air force jets flew reconnaissance missions over the vast disaster zone.
The Tokyo and Osaka police forces and the health ministry also all quickly dispatched medical and rescue teams.
Among the international help pledged, a team from South Korea, with five rescue personnel and two sniffer dogs, jetted in.
Japan said it had been offered help by scores of governments -- among them China, with whom Tokyo has sometimes awkward relations.
The United States, which occupied Japan after World War II and is the country's main security ally, has many of its forces stationed on the southern island of Okinawa, far from the quake zone.
Two aircraft carriers were en route to the disaster zone -- the USS George Washington, which is based near Tokyo, and the USS Ronald Reagan, which was on its way to South Korea for exercises and has been redirected.
