Japan: Nuclear crisis level raised to highest level
The Fukushima Daiichi nuclear plant was crippled by last month's earthquake and tsunami
Japanese authorities have raised the measure of severity of their nuclear crisis to the highest level, officials say.
The decision was taken due to radiation measured at the damaged Fukushima Daiichi power plant, NHK reported.
The highest level for nuclear accidents (seven) had previously only applied to the Chernobyl disaster in 1986.
Meanwhile a 6.3-magnitude earthquake was reported off eastern Japan, the second tremor in as many days.
The aftershocks come a month after a huge quake and tsunami hit Japan, leaving nearly 28,000 dead or missing.
'Preliminary assessment'
The raising of the severity level of the crisis at the Fukushima Daiichi plant was announced on national television by an official with the Nuclear Safety Commission of Japan.
"This is a preliminary assessment, and is subject to finalisation by the International Atomic Energy Agency," said an official at the Nuclear and Industrial Safety Agency (NISA), the government's nuclear watchdog, which made the announcement with the Nuclear Safety Commission, Reuters reported.
Continue reading the main story Analysis Until now the incident at Fukushima was rated a level five, so upgrading to a level seven is a worrying jump. But officials here point out that the change is not being made because of a sudden deterioration at the plant. Rather a full assessment of the available data now suggests that Fukushima merits the higher rating according to internationally agreed standards. There is no suggestion that the decision is related to a recent series of powerful aftershocks. The move comes a day after the government announced it was extending the exclusion zone around the nuclear plant. Five communities where levels of radiation could pose a long term risk to health will be evacuated over the next month.
The level seven signifies a "major accident" with "wider consequences" than the previous level, officials say.
"We have upgraded the severity level to seven as the impact of radiation leaks has been widespread from the air, vegetables, tap water and the ocean," said Minoru Oogoda of Japan's Nuclear and Industrial Safety Agency.
However, a nuclear safety agency spokesman told reporters the leaks were still small compared to those of the Chernobyl accident.
"In terms of volume of radioactive materials released, our estimate shows it is about 10% of what was released by Chernobyl," he said.
The decision to raise the threat level was made after radiation of 10,000 terabequerels per hour had been estimated at the stricken plant for several hours.
That would classify the crisis at level seven on the International Nuclear and Radiological Event Scale (Ines).
It was not clear when that level had been reached. The level has subsequently dropped to less than one terabequerel an hour, the report said.
The severity level of Japan's nuclear crisis has so far been set at five, the same as that of the accident at Three Mile Island in the US in 1979.
Japan has also said it is extending the evacuation zone around the crippled nuclear plant because of radiation concerns.
The zone will be widened to encompass five communities beyond the existing 20-km (12-mile) radius, following new data about accumulated radiation levels, officials said.
Japan's nuclear commission said that according to preliminary results, the cumulative level of external radiation exceeded the yearly limit of 1 millisieverts in areas extending more than 60 kms (36 miles) to the north-west of the plant and about 40 km to the south-southwest.
On Monday, a 7.1-magnitude quake hit north-east Japan, leaving three people dead. It also triggered a brief tsunami warning, and forced workers to evacuate the Fukushima Daiichi plant.
Tuesday's quake rocked buildings in the capital, Tokyo.
There were no immediate reports of fresh damage, though Japan's Narita international airport temporarily closed its runways, and metro and train services were interrupted.
The cooling systems at the Fukushima Daiichi nuclear plant were damaged in last month's disaster and workers have been struggling to prevent several reactors from overheating.
Officials have warned it will be several months before the situation at the nuclear facility is brought fully under control.
Tokyo Electric Power Co (Tepco) said on Tuesday that a fire had broken out briefly at Reactor 4, before being extinguished.
The official death toll from the disaster is 13,130, while 13,718 remain unaccounted for. More than 150,000 people have been made homeless.
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A new magnitude 6.6 aftershock yesterday triggered a mudslide which left six people dead. 
The crisis at a  on the northeast coast of Japan is now as severe as the  in 1986, officials have said. Radiation is continuing to leak from the plant, which was damaged during the devastating magnitude 9.0 earthquake and tsunami last month, which left thousands dead. Japanese authorities have warned the crisis is now a "major accident" with "wider consequences" than previously thought.

A spokesperson for , the Japanese government nuclear authority, said officials had upgraded the crisis to a level seven on the —the same applied to the Chernobyl disaster—because of a number of factors, including the detection of radiation in crops. "We have upgraded the severity level to seven as the impact of radiation leaks has been widespread from the air, vegetables, tap water and the ocean," he said.

 
, the operator of the plant, has warned radiation was continuing to leak from the site and the magnitude of the crisis could exceed that of Chernobyl. Despite this, Japanese nuclear safety officials have insisted the leakage of radiation was small compared to the devastated plant in the former . "In terms of volume of radioactive materials released, our estimate shows it is about ten percent of what was released by Chernobyl," one nuclear official said.

The news comes as a new blow after another powerful aftershock yesterday which left at least six people dead after they were killed in a  in the city of . The landslide, which destroyed numerous homes, was triggered by a  6.6 aftershock which came exactly a month after the 9.0 magnitude earthquake. Fire officials in the city said three people had already been rescued and taken to hospital, and emergency workers were working to free an unknown number of others.
The International Nuclear Events Scale; the accidents at the Fukushima I have been elevated to level seven, the highest level on the scale, putting it on par with the , originally the accidents were rated at level five, the same level of the . 
Workers at the damaged Fukushima nuclear plant returned after they were briefly evacuated following the earthquake, and officials issued tsunami warnings for the northeast coast which were later cancelled. Workers have been fighting a desperate battle to prevent the reactors from overheating and entering . Raging fires burned into the night after the earthquake, and TEPCO reported widespread power outages; hundreds of thousands of homes and businesses had power cut off.

Reports of the change in severity at the damaged nuclear plant followed the announcement that the  around the site was to be expanded. A spokesperson for the government confirmed the radius of the zone would be expanded to include another five communities over the next several weeks. He stressed there was "no need to evacuate immediately" but said concerns had been raised over health risks from the leaking radiation.

The new development at the plant and the aftershock are new blows to a country wounded after the massive earthquake in March, which caused a tsunami that washed away whole towns and villages along the country's northeast coast. Thousands of bodies have been recovered, and many more are still unaccounted for, many left under mounds of rubble or washed out to sea. More than 150,000 people remain displaced, living in emergency shelters.


Before the aftershock struck yesterday, survivors of the first earthquake marked the time it hit a month ago with a  across the country. Writing to seven international newspapers, , the ,  expressed his gratitude to people globally for their support. "Through our own efforts and with the help of the global community, Japan will recover and come back even stronger. We will then repay you for your generous aid," he wrote. "With this in our hearts, we now stand together dedicated to rebuilding the nation."



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de:Nachbeben in Japan – Behörden weiten Sicherheitszone aus
es:Aumentan el nivel de alerta radioactiva en la central nuclear Fukushima
fr:Les accidents de Fukushima évalués de niveau 7 par les autorités japonaises
pl:Fukushima: łączna ocena INES awarii podniesiona do 7. stopnia