Marked 7 in severity and reclassified as a ‘major accident’

The nuclear radiation crisis at the Fukushima Daiichi plant in Japan was reclassified on Tuesday as a “major accident” with the same worst-case rating as the 1986 Chernobyl disaster.

However, Japanese authorities quickly sought to reassure the international community about the continuing efforts to end the Fukushima crisis that was mainly triggered by natural disasters. Chernobyl, in contrast, was seen more primarily as an industrial accident in the civil nuclear domain.

The level of the Fukushima crisis was now “provisionally” raised from ‘five' to the worst-possible ‘seven' on the International Nuclear and Radiological Event Scale (INES). The previous rating of ‘five', assigned on the basis of radiation readings one week after the March 11 temblor and tsunami, was the same as that of the 1979 civil-nuclear accident in the U.S.

A top official of Japan's Nuclear and Industrial Safety Agency (NISA), Hidehiko Nishiyama, said on Friday that the new assessment about the severity was based on the data obtained since March 18. NISA's estimate, though, was that “the total amount of radioactive substances released [so far, at Fukushima] is 10 per cent of that of the Chernobyl accident.”

However, a cautionary note was sounded by an official of the Tokyo Electric Power Company, which operates the Daiichi plant. He said its cumulative emissions of radioactive substances might eventually exceed the total amount spewed at Chernobyl in the event of failure to seal the Fukushima leaks.

Punctuating such professional narratives was some political discourse, too. Prime Minister Naoto Kan said in Tokyo that the overall level of discharge of radioactive substances at Fukushima was actually beginning to “decline” now. Chief Cabinet Secretary Yukio Edano said: “Unlike Chernobyl, we have been able to come this far [at Fukushima] without causing any direct harm to human health. We will continue our efforts to resolve the situation, giving top priority to keeping people safe from health hazards.”

The Vienna-based IAEA said a score of ‘seven' under the INES framework would imply the occurrence of “a major release of radioactive material, with widespread health and environmental effects, requiring the implementation of planned and extended countermeasures.”

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