JAPAN BATTLES TO STAVE OFF POSSIBLE NUCLEAR MELTDOWN

People take shelter as a ceiling collapses in a bookstore during an earthquake in Sendai, northeastern Japan

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Japanese media say officials have detected caesium, one of the elements released when overheating causes core damage, around reactor at Fukushima No 1 plant in Futuba
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Japan tsunami and earthquake - live coverage

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Houses swallowed by tsunami waves burn in Natori, Miyagi Prefecture (state) after Japan was struck by a strong earthquake off its northeastern coast Friday, March 11. (Kyodo News/Associated Press)

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A file picture of the Kashiwazaki-Kariwa nuclear power plant reactor No 7, in Niigata prefecture, Japan, that was damaged in the quake. Photograph: Franck Robichon/EPA 

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Sendai Airport is surrounded by waters in Miyagi prefecture (state), Japan, after a ferocious tsunami spawned by one of the largest earthquakes ever recorded slammed Japan's eastern coast Friday, March 11, 2011. (Kyodo News/Associated Press) 

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Workers are battling to stave off a possible nuclear meltdown at a plant in north-eastern Japan as the country struggles with the aftermath of Friday's enormous earthquake and tsunami.

Japanese media said officials had detected caesium, one of the elements released when overheating causes core damage, around the reactor at Fukushima No 1 plant in Futuba, 150 miles (240km) north of Tokyo..
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The Tokyo Electric Power Company (Tepco) said it did not believe a meltdown was under way, but Ryohei Shiomi, an official with Japan's nuclear safety commission, said that it was possible.

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Houses are swept by a tsunami in Natori City in northeastern Japan March 11, 2011. A massive 8.9 magnitude quake hit northeast Japan on Friday, causing many injuries, fires and a ten-metre (33-ft) tsunami along parts of the country's coastline. There were several strong aftershocks and a warning of a 10-metre tsunami following the quake, which also caused buildings to shake violently in the capital Tokyo. (Reuters)

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Experts and authorities played down the dangers of a Chernobyl-style disaster, saying they believed a partial meltdown was controllable. The government urged people to remain calm.

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Officials had earlier evacuated 20,000 residents living within 6 miles of the plant on the orders of the Prime Minister, Naoto Kan, who had inspected it via helicopter. Experts told Associated Press that the risk area was 4 miles.
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A massive tsunami sweeps in to engulf a residential area after a powerful earthquake in Natori, Miyagi Prefecture in northeastern Japan. (Reuters) #

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The crisis began when the 8.9 magnitude shock cut off power, turning off the water supply needed to cool the system. The tsunami is thought to have cut off the backup diesel generator an hour later, leading to pressure rising rapidly within the reactor.

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Tsunami swirls near a port in Oarai, Ibaraki Prefecture (state) after Japan was struck by a strong earthquake off its northeastern coast Friday, March 11. (Kyodo News/Associated Press) #

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Broadcaster NHK said attempts to vent radioactive gas to lower the pressure had been suspended because the radiation level on one valve was higher than expected, heightening the risk of exposing workers to radiation.
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Earlier in the day a Japanese nuclear safety panel said radiation levels were 1,000 times higher than normal in a control room and eight times higher than normal just outside the plant. Workers were changing shifts frequently.

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A helmeted man walks past the rubbles and a burning building after a powerful earthquake, the largest in Japan's recorded history, slammed the eastern coasts in Iwaki city, Fukushima prefecture, Japan. (Kyodo News/Associated Press) 

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Tepco has also declared an emergency at the Fukushima No 2 plant after reporting problems with a reactor there.

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The chief cabinet secretary, Yukio Edano, said the pressure control system was not functioning at the plant's three reactors. Officials were evacuating residents within a 2 mile radius and had ordered those with 6 miles to stay indoors, NHK said.
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Giant fireballs rise from a burning oil refinery in Ichihara, Chiba Prefecture (state) after Japan was struck by a strong earthquake off its northeastern coast. (Kyodo News/Associated Press) 

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Naoto Sekimura, a professor at the University of Tokyo, told AP a major radioactive disaster was unlikely.

"No Chernobyl is possible at a light water reactor. Loss of coolant means a temperature rise, but it also will stop the reaction," he said.

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An oncoming tsunami strikes the coast in Natori City, Miyagi Prefecture, northeastern Japan March 11, 2011. The biggest earthquake to hit Japan in 140 years struck the northeast coast on Friday, triggering a 10-metre tsunami that swept away everything in its path, including houses, cars and farm buildings on fire. (Reuters)

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 "Even in the worst-case scenario, that would mean some radioactive leakage and equipment damage, but not an explosion. If venting is done carefully, there will be little leakage ~ certainly not beyond the 3km radius."

A partial meltdown in one of the light water reactors at Three Mile Island in 1979 resulted in the release of radioactive gases in the most serious incident in the history of the US nuclear power industry. The reactor was eventually brought under control despite a series of errors.

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Across the worst hit area of Japan, the north-east Tohoku region, at least 630 people are dead and a similar number missing, according to police sources, with 1,128 injured. The country has mobilized 50,000 rescuers but they have yet to reach the most severely affected areas.

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Earthquake-triggered tsumanis sweep shores along Iwanuma in northern Japan. (Kyodo News/Associated Press) 

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Residents woke up after a freezing night on rooftops and in emergency shelters to a sea of mud, water and debris. Earthquakes continued to rock the north-east coast overnight, although some said the worst tremors appeared to be subsiding.

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Japan downgraded tsunami warnings in most areas but Tohoku remained on high alert for waves up to 10 metres high.

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A tsunami, tidal wave smashes vehicles and houses at Kesennuma city in Miyagi prefecture, northern Japan. (AFP/Getty Images)

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The tsunami has reached countries across the Pacific region but there were no reports of major damage outside Japan.

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Images shot from helicopters showed many people still crowding the rooftops of buildings surrounded by water and mud. Some, including children, were winched to safety by rescuers.

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An aerial shot shows vehicles ready for shipping being carried by a tsunami tidal wave at Hitachinaka city in Ibaraki prefecture on March 11, 2011. A massive 8.8-magnitude earthquake shook Japan, unleashing a powerful tsunami that sent ships crashing into the shore and carried cars through the streets of coastal towns. (AFP/Getty Images)

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Other footage showed the letters SOS spelled out on the roof of a hospital in Iwanuma, Miyagi prefecture.

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Photographs from Sendai ~ one of the worst hit cities ~ showed families crammed into schools.

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"The flood came in from behind the store and swept around both sides. Cars were flowing right by," said Wakio Fushima, who owns a convenience store in Sendai, which has around 1 million inhabitants and is 80 miles from the quake's epicentre.

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Witnesses said the tsunami had reached about six miles inland.

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Houses swept by a tsunami smoulder near Sendai Airport. (Reuters

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"The tsunami was unbelievably fast. Smaller cars were being swept around me and all I could do was sit in my truck," said driver Koichi Takairin, 34, who was trapped in his four-tonne vehicle by the torrent.

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Hundreds queued outside supermarkets for basic supplies and petrol stations were crowded with cars. 

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Shores are submerged in Natori city, Miyagi prefecture (state), Japan, after a ferocious tsunami spawned by one of the largest earthquakes ever recorded, slammed Japan's eastern coasts Friday, March 11, 2011. (Kyodo News

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Authorities warned citizens in northern Japan to be prepared for severe power cuts due to the shutdown of nuclear plants, which provide about 30% of the country's electricity.

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More than 1 million households are without water.
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Residents walk through the rubles of residents collapsed by a powerful earthquake in Iwaki, Fukushima prefecture Japan. (Kyodo News/Associated Press)

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Phone voice services are also down across much of the north-east, although data services seemed to be working sporadically.

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Buildings burn in Yamada town, Iwate prefecture (state) after Japan's biggest recorded earthquake hit March 11. (Associated Press/The Yomiuri Shimbun)