jbo竞博（中国）科技有限公司官网

Japan has raised its assessment of the accident at the Fukushima nuclear power plant to the most serious level on a 7-step international scale, equivalent to the 1986 Chernobyl disaster.

Japan’ s nuclear regulator increased its assessment on the International Atomic Energy Agency scale – from the previous level 5 – because of the impact that radiation leaking from the plant would have on human health and the environment. Japan had initially classified the incident as a level 4 before later raising it to level 5.

Japan’ s nuclear regulator increased its assessment on the International Atomic Energy Agency scale – from the previous level 5 – because of the impact that radiation leaking from the plant would have on human health and the environment. Japan had initially classified the incident as a level 4 before later raising it to level 5.

While the new assessment puts the Fukushima Daiichi incident on a par with Chernobyl, the nuclear regulator said the amount of radioactive contamination that has escaped from the plant since it was damaged by Japan’ s March 11 earthquake and tsunami was around one tenth of the radiation that escaped from the plant in the former Soviet Union.

“ There are still major differences from Chernobyl,” said Hidehiko Nishiyama, an official at the Nuclear and Industrial Safety Agency.

Mr Nishiyama stressed that the nuclear reactor at Chernobyl exploded, spreading radiation over a wide area, which has not happened at Fukushima. Also, there have not been any deaths from contamination – another difference from the 1986 accident.

“ There are still major differences from Chernobyl,” said Hidehiko Nishiyama, an official at the Nuclear and Industrial Safety Agency.

Nevertheless, workers at Fukushima Daiichi have not been able to stem radiation leakage from the plant, which has led to the evacuation of thousands of local residents and a ban on vegetable shipments from Fukushima and surrounding prefectures.

Twenty-one workers at the nuclear plant have been exposed to radiation doses over 100 millisieverts, normally the maximum annual amount for nuclear workers in emergency situations.

The decision to raise Fukushima Daiichi to level 7 comes one month after its safety systems were crippled by the tsunami that followed the March 11 earthquake, which ravaged large parts of northeastern Japan and sent powerful waves several kilometres inland.

Efforts to stabilise the plant, which has been leaking radioactive iodine-131 and caesium-137, have been hampered by high levels of radiation inside and around the plant, which is rapidly filling up with highly radioactive cooling water.

Work to transfer radioactive water from the trench, or tunnel, to a temporary storage vessel at nuclear reactor 4 was halted after a magnitude 6.6 earthquake rocked northeastern Japan again on Monday, one month after the March 11 earthquake.

The government on Monday also widened the evacuation zone around Fukushima Daiichi to beyond the previous 30km radius, citing the possibility that radiation levels could exceed 20 millisieverts over a year, or about 10 times the dose from normal background radiation.

Twenty-one workers at the nuclear plant have been exposed to radiation doses over 100 millisieverts, normally the maximum annual amount for nuclear workers in emergency situations.

（Source:FTchinese.com By Michiyo Nakamoto,Jonathan Soble in Tokyo
http://www.ftchinese.com/story/001038036）