Nuclear Plant Explotion

While saying there are no indications yet of dangerously high radiation levels in the atmosphere, a Japanese government official said Sunday that there is a "possibility of a meltdown" at two of the country's nuclear reactors.

Chief Cabinet Secretary Yukio Edano told reporters that officials still do not know if there have been meltdowns in the No. 1 and No. 3 reactors at the Fukushima Daiichi's nuclear facility in northeast Japan. But as they attempt to cool down radioactive material and release pressure inside the reactors, he said authorities were working under the presumption that such meltdowns have taken place.

"We do believe that there is a possibility that meltdown has occurred. It is inside the reactor. We can't see. However, we are assuming that a meltdown has occurred," he said of the No. 1 reactor. "And with reactor No. 3, we are also assuming that the possibility of a meltdown as we carry out measures."

A meltdown is a catastrophic failure of the reactor core, with a potential for widespread radiation release.

Edano's comments confirmed an earlier report from an official with Japan's Nuclear and Industrial Safety Agency, who had told CNN, "we see the possibility of a meltdown."

Though Toshihiro Bannai, director of the agency's international affairs office, said engineers have been unable to get close enough to the core to know what's going on, he based his conclusion on the fact that they measured radioactive isotopes in the air Saturday night.

"What we have seen is only the slight indication from a monitoring post of cesium and iodine," he said.

But Bannai added that he didn't believe a disaster was looming.

"We actually have very good confidence that we will resolve this," he said.

Edano, too, raised few alarms during his press conference Sunday. He based his optimism in large part on measurements of radiation outside the nuclear plant, conceding fluctuations may occur while stating that levels have generally decreased.

"We are continuing to monitor the radiation, but it is (under) control," he said.

Edano said that nine people have tested positive for high radiation levels on their skin and clothing, with doctors now trying to determine if they were impacted internally. Medical care, including radiation screening, will be offered to those who are being evacuated from the nuclear zone, the secretary added.

The Japanese government was preparing to distribute iodine tablets to residents, the IAEA said. Iodine is commonly recommended to block the uptake by the thyroid gland of radioactive iodine.

The problems at the Daiichi plant began Friday, when the 8.9-magnitude quake struck off the eastern shore of Miyagi Prefecture. The quake 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 that pumped water into the reactor containment unit to keep the nuclear fuel cool.

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.

Pressure had been mounting inside the reactors as steam built up inside, because water meant to cool the fuel rods was boiling.

As of Sunday morning, winds in northeast Japan were blowing out to sea at 5-15 mph, said CNN Meteorologist Taylor Ward. But they were expected to reverse direction by Monday night, he said. The Daiichi plant is located about 160 miles (260 kilometers) north of Tokyo.

Plant officials are also injecting sea water and boron into the plant in an effort to cool its nuclear fuel and stop any reactions.

Boron, a chemical element, was being added to the water "to sort of stymie other potential nuclear reactions," according to Robert Alvarez, senior scholar at the Institute for Policy Studies and a former senior policy adviser to the U.S. secretary of energy. He described the plan to use salt water as "an act of desparation" by Japanese authorities, who seemed unable to deliver fresh water or plain water to cool the reactor and stabilize it.

Earlier, Edano had pointed out another potential challenge -- saying, without elaboration, that "some of the readings in the measurement equipment were not accurate."

The detection of a cesium isotope -- as noted by Bannai -- indicates that the reactors' nuclear fuel cladding has failed, said Ken Bergeron, a physicist and former scientist at Sandia National Laboratories.

"Now we have to hope that the containment building will succeed in preventing major amounts of radioactivity" from escaping, he said. Fukushima Daiichi facility has such a building -- something that Chernobyl, the Soviet nuclear plant that famously melted down in 1986, did not have.

Cesium 137 can remain dangerous for 600 years and is associated with a number of cancers, said Dr. Ira Helfand, a member of the board of Physicians for Social Responsibility.

Some experts said the flow of information from the agency has not been fast enough.

But IAEA Director General Yukiya Amano defended the Japanese response. "I know the Japanese authorities are working their hardest to gather the necessary details and ensure safety under difficult and constantly evolving circumstances," he said in a statement.

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 downplayerd such a scenario, insisting the situation appears under control and that radiation levels in the air are dangerous. Still, as what they described as "a precuation," more than 200,000 people who live within 20 kilometers (12 miles) of the plant have been ordered to leave the area. A similar evacuation order has been issued for those with 10 kilometers of the Fukashima Daini nuclear facility, a separate plant also in Fukashima prefecture.

Even absent this, nuclear materials expert Joseph Cirincione -- president of the U.S.-based Ploughshares Fund, a firm involved in security and peace funding -- ranks this scenario third, behind Chernobyl and the 1979 partial meltdown of a reactor core at the Three Mile Island nuclear plant in Pennsylvania, among history's worst nuclear power crises.

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.

While experts acknowledged that Japan's nuclear program is very well respected, physicist Ken Bergeron saying that now "we're in uncharted territory."

"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."

Japan weighs need to bury nuclear plant

TOKYO (Reuters) - Japanese engineers conceded on Friday that burying a crippled nuclear plant in sand and concrete may be the only way to prevent a catastrophic radiation release, the method used to seal huge leakages from Chernobyl in 1986.

Officials said they still hoped to fix a power cable to at least two reactors to restart water pumps needed to cool overheating nuclear fuel rods. Workers also sprayed water on the No.3 reactor, one of the most critical of the plant's six.

It was the first time the facility operator had acknowledged that burying the sprawling complex was an option, a sign that piecemeal actions such as dumping water from military helicopters were having little success.

"It is not impossible to encase the reactors in concrete. But our priority right now is to try and cool them down first," an official from the plant operator, Tokyo Electric Power Co, told a news conference.

As Japan entered its second week after a 9.0-magnitude earthquake and 10 meter (33-foot) tsunami flattened coastal cities and killed thousands of people, the world's worst nuclear crisis since Chernobyl looked far from over.

Millions in Tokyo remained indoors on Friday, fearing a blast of radioactive material from the complex, 240 km (150 miles) to the north, although prevailing winds would likely carry contaminated smoke or steam away from the densely populated city to dissipate over the Pacific Ocean.

Radiation did not pose an immediate risk to human health outside the vicinity of the plant, said Michael O'Leary, the World Health Organisation's representative in China.

"At this point, there is still no evidence that there's been significant radiation spread beyond the immediate zone of the reactors themselves," O'Leary told reporters in Beijing.

Japan's nuclear disaster has triggered global alarm and reviews of safety at atomic power plants around the world.

President Barack Obama, who stressed the United States did not expect harmful radiation to reach its shores, said he had ordered a comprehensive review of domestic nuclear plants and pledged Washington's support for Japan.

The Group of Seven rich nations, stepping in together to calm global financial markets after a tumultuous week, agreed to join in rare concerted intervention to restrain a soaring yen.

The top U.S. nuclear regulator said it could take weeks to reverse the overheating of fuel rods at the Fukushima Daiichi plant.

"This is something that will take some time to work through, possibly weeks, as you eventually remove the majority of the heat from the reactors and then the spent-fuel pools," Nuclear Regulatory Commission Chairman Gregory Jaczko told a news conference at the White House.

Yukiya Amano, head of the Vienna-based International Atomic Energy Agency (IAEA), arrived in his homeland on Friday with an international team of experts after earlier complaining about a lack of information from Japan.

Graham Andrew, his senior aide, called the situation at the plant "reasonably stable" but the government said white smoke or steam was still rising from three reactors and helicopters used to dump water on the plant had shown exposure to small amounts of radiation.

"The situation remains very serious, but there has been no significant worsening since yesterday," Andrew said.

The nuclear agency said the radiation level at the plant was as high as 20 millisieverts per hour. The limit for the workers was 100 per hour.

Even if engineers restore power at the plant, it was not clear the pumps would work as they may have been damaged in the earthquake or subsequent explosions and there are fears of the electricity shorting and causing another blast.

Japan's nuclear agency spokesman, Hidehiko Nishiyama, said it was also unclear how effective spraying water on the reactors from helicopters had been on Thursday. The priority was to get water into the spent-fuel pools, he said.

"We have to reduce the heat somehow and may use seawater," he told a news conference. "We need to get the reactors back online as soon as possible and that's why we're trying to restore power to them."

Asked about burying the reactors in sand and concrete, he said: "That solution is in the back of our minds, but we are focused on cooling the reactors down."

Jaczko said the cooling pool for spent-fuel rods at the complex's reactor No.4 may have run dry and another was leaking.

An official at the plant operator said he expected power to be restored at its most troubled and damaged reactors -- No.3 and No.4 -- by Sunday. Engineers are trying to reconnect power to the least damaged reactors first.

DOLLAR GAINS AS FINANCIAL LEADERS INTERVENE

The U.S. dollar surged more than two yen to 81.80 after the G7's pledge to intervene, leaving behind a record low of 76.25 hit on Thursday.

Japan's Nikkei share index ended up 2.7 percent, recouping some of the week's stinging losses. It has lost 10.2 percent this week.

U.S. markets, which had tanked earlier in the week on the back of the crisis, rebounded on Thursday but investors were not convinced the advance would last.

The yen has seen steady buying since the earthquake, as Japanese and international investors closed long positions in higher-yielding, riskier assets such as the Australian dollar, funded by cheap borrowing in the Japanese currency.

Expectations that Japanese insurers and companies would repatriate billions of dollars in overseas funds to pay for a reconstruction bill that is expected to be much costlier than the one that followed the Kobe earthquake in 1995 also have helped boost the yen.

RADIATION LEVELS IN TOKYO BARELY ABOVE AVERAGE

The government had warned Tokyo's 13 million residents on Thursday to prepare for a possible large-scale blackout but later said there was no need for one. Still, many firms voluntarily reduced power, plunging parts of the usually neon-lit city in darkness.

The U.S. embassy in Tokyo has urged citizens living within 80 km (50 miles) of the Daiichi plant to evacuate or remain indoors "as a precaution," while Britain's foreign office urged citizens "to consider leaving the area." Other nations have urged nationals in Japan to leave the country or head south.

Japan's government has told everyone living within 20 km (12 miles) of the plant to evacuate, and advised people within 30 km (18 miles) to stay indoors.

At its worst, radiation in Tokyo has reached 0.809 microsieverts per hour this week, 10 times below what a person would receive if exposed to a dental x-ray. On Thursday and Friday, radiation levels were within average levels.

The plight of hundreds of thousands left homeless by the earthquake and tsunami worsened following a cold snap that brought heavy snow to worst-affected areas.

Supplies of water, heating oil and fuel are low at evacuation centers, where many survivors wait bundled in blankets.

About 30,000 households in the north were still without electricity in near-freezing weather, Tohuku Electric Power Co. said, and the government said at least 1.6 million households lacked running water.

The National Police Agency said on Friday it had confirmed 5,692 deaths from the quake and tsunami disaster, while 9,522 people were unaccounted for in six prefectures.

(Additional reporting by Linda Sieg, Nathan Layne, Elaine Lies, Leika Kihara and Mayumi Negishi; Writing by John Chalmers; Editing by Dean Yates)

Explosion at Fukushima nuclear plant

A powerful explosion has hit a nuclear power station in north-eastern Japan which was badly damaged in Friday's devastating earthquake and tsunami.

A building housing a reactor was destroyed, but authorities said the reactor itself was intact.

The government sought to play down fears of a meltdown at the Fukushima 1 plant.

But officials later announced the cooling system of a second reactor at the plant had failed.

The news sparked fears of a the risk of a further explosion or leak of radioactive material.

A huge rescue and relief operation is under way in the region after the earthquake and subsequent tsunami, which are thought to have killed more than 1,000 people.

Tokyo Electric Power said four of its workers had been injured in Saturday's blast at Fukushima, 250km (155 miles) north of Tokyo, but that their injuries were not life-threatening.

An evacuation zone around the damaged nuclear plant has been extended to 20km (12.4 miles) from 10km, and a state of emergency declared.

An estimated 200,000 people have been evacuated from the area, the International Atomic Energy Agency says.

The government has urged residents to remain calm and is preparing to distribute iodine to anyone affected.

Tests showed at least three patients evacuated from a hospital near the plant had been exposed to radiation, public broadcaster NHK quoted local government officials as saying. They were among a group of people waiting outside the hospital for rescue helicopters when the explosion hit the plant.

Government spokesman Yukio Edano said the force of the explosion had destroyed the concrete roof and walls of a building around the plant's number one reactor, but a steel container encasing the reactor had not been ruptured.

Mr Edano said radiation levels around the plant had fallen after the explosion. He added that sea water was being pumped into the site to lower temperatures.

Before the explosion, Japan's nuclear agency had said that radioactive caesium and iodine had been detected near the number one reactor. The agency said this could indicate that containers of uranium fuel inside the reactor may have begun melting.

Air and steam, with some level of radioactivity, was earlier released from several of the reactors at both plants in an effort to relieve the huge amount of pressure building up inside.

Scenes of devastation

The tsunami that followed the 8.9-magnitude earthquake wreaked havoc along a huge stretch of on Japan's north-east coast, sweeping far inland and devastating a number of towns and villages.

The BBC's Damian Grammaticas in the coastal city of Sendai, in Miyagi prefecture, says the scenes of devastation there are astonishing - giant shipping containers have been swept inland and smashed against buildings, and fires are still burning close to the harbour.

Police said between 200 and 300 bodies were found in just one ward of the city.

The town of Rikuzentakada, Iwate, was reported as largely destroyed and almost completely submerged. NHK reported that soldiers had found up to 400 bodies there.

NHK reports that in the port of Minamisanriku, Miyagi, the authorities say that about 7,500 people were evacuated to 25 shelters after Friday's quake but they have been unable to contact the town's other 10,000 inhabitants.

A local official in the town of Futaba, Fukushima, said more than 90% of the houses in three coastal communities had been washed away by the tsunami.

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

Tens of thousands of troops backed by ships and helicopters have been deployed on rescue and relief missions. More than 215,000 people are said to be living in 1,350 temporary shelters in five prefectures.

International disaster relief teams are being sent to Japan, with the United Nations helping to co-ordinate the operation.

President Barack Obama has pledged US assistance. One US aircraft carrier that was already in Japan will help with rescue and relief efforts, and a second is on its way.

Japan's worst previous earthquake was of 8.3 magnitude and killed 143,000 people in Kanto in 1923. A magnitude 7.2 quake in Kobe killed 6,400 people in 1995.

Radiation Dangers Heightened at Japanese Nuclear Plant

The steel container protecting a nuclear reactor at a plant facing a possible meltdown was not damaged in an explosion that injured four workers and destroyed the exterior walls of the plant, a Japanese government spokesman said today.

The blast at the Fukushima Daiichi plant occurred outside the containment vessel and did not damage the nuclear reactor itself, which would cause radioactive material to leak out, a government spokesman Yukio Edano said.

Contrary to initial reports of radiation levels rising around the Fukushima Daiichi plant after the blast, Edano said that radiation is decreasing and that the pressure inside the reactor is also dropping.

"Based on this situation, we are concerned about the nuclear reactor and have decided to fill the reactor with sea water" to further decrease pressure and cool down the reactor, Edano said.

Flooding the containment vessel with sea water mixed with boron instead of fresh water is an unusual measure, according to Robert Alvarez, a senior scholar at the Institute for Policy Studies, who described it as a "Hail Mary pass" but a necessary step to keep the reactor core covered and the containment vessel cool. The restoration of power to the plant remains critical to prevent against the possibility of an outright meltdown.

Third explosion rocks Japanese nuclear plant

Japan's nuclear crisis deepened dramatically Tuesday. As safety officials sought desperately to avert catastrophe, the government said radioactive material leaking from reactors was enough to "impact human health" and the risk of more leaks was "very high."

In a nationally televised statement, Prime Minister Naoto Kan said that radiation has spread from four reactors of the Fukushima Dai-ichi nuclear plant in Fukushima province that was one of the hardest-hit in Friday's 9.0-magnitude earthquake and the ensuing tsunami.

He urged anyone within 19 miles (30 kilometers) of the plant to stay indoors or risk getting radiation sickness.

"The level seems very high, and there is still a very high risk of more radiation coming out," Kan said.

A cascade of three explosions at the Fukushima Dai-ichi nuclear complex was set in motion when last Friday's quake and tsunami knocked out power, crippling the cooling systems needed to keep nuclear fuel from going into full meltdown.

The latest blast was early Tuesday in the plant's Unit 2 near a suppression pool, which removes heat under a reactor vessel, plant owner Tokyo Electric Power Co. said. Shigekazu Omukai, a spokesman for Japan's nuclear safety agency, said the nuclear core was not damaged but that the bottom of the surrounding container may have been.

Chief Cabinet Secretary Yukio Edano said a fourth reactor at the complex was on fire and more radiation had been released.

"Now we are talking about levels that can damage human health. These are readings taken near the area where we believe the releases are happening. Far away, the levels should be lower," he said.

"Please do not go outside. Please stay indoors. Please close windows and make your homes airtight. Don't turn on ventilators. Please hang on your laundry indoors," he said.

"These are figures that potentially affect health, there is no mistake about that," he said.

Japanese officials had previously said radiation levels at the plant were within safe limits, and international scientists said that while there were serious dangers, there was little risk of a catastrophe like Chernobyl in Ukraine, where the reactor exploded and released a radiation cloud over much of Europe.

Unlike the plant in Japan, the Chernobyl reactor was not housed in a sealed container to prevent the release of radiation.

Japanese authorities have been injecting seawater as a coolant of last resort, and advising nearby residents to stay inside to avoid contamination.

"It's like a horror movie," said 49-year-old Kyoko Nambu as she stood on a hillside overlooking her ruined hometown of Soma, about 25 miles (40 kilometers) from the plant. "Our house is gone and now they are telling us to stay indoors.

"We can see the damage to our houses, but radiation? ... We have no idea what is happening. I am so scared."

Earlier blasts Monday and Saturday injured 15 workers and military personnel and exposed up to 190 people to elevated radiation. Officials said those explosions had been linked to the venting of buildups of steam at two of the troubled reactors and that they had not compromised their inner containers.

The nuclear woes compounded challenges already faced by the Tokyo government as it dealt with twin disasters that flattened entire communities and left as many as 10,000 or more dead.

It also raised global concerns about the safety of nuclear power at a time when it has seen a resurgence as an alternative to fossil fuels.

The head of the International Atomic Energy Agency said the Japanese government has asked the agency to send experts to help.

Japan's meteorological agency reported one good sign. It said the prevailing wind in the area of the stricken plant was heading east into the Pacific, which would help carry away any radiation.