Greenpeace study ranks Fukushima as Chernobyl Level 7 incident

Feature story - March 25, 2011
Hamburg — As new reports emerge of highly radioactive water leaks at Fukushima’s reactor 3, a new analysis prepared for Greenpeace Germany by nuclear safety expert Dr Helmut Hirsch shows that Japan’s nuclear crisis has already released enough radioactivity to be ranked at Level 7 on the International Nuclear Event Scale (INES). This is the scale’s highest level, and equal to the 1986 Chernobyl nuclear disaster.

Dr. Hirsch’s assessment, based on data published by the French government's radiation protection agency (IRSN) and the Austrian governments Central Institute for Meteorology and Geodynamics (ZAMG) found that the total amount of radionuclides iodine-131 and caesium-137 released between March 11 and March 23 has been so high that the Fukushima crisis already equates to three INES 7 incidents. 

"What is happening at Fukushima is just as serious as Chernobyl.  It’s crucial that Japan’s authorities, the nuclear industry and the IAEA immediately stop their downplaying of the threat of radioactive contamination, and instead provide clear and honest communication about the risks to public health in order to protect people”, said Greenpeace energy campaigner Dr Rianne Teule. 

”The events of the last two weeks are a wake up call for governments around the world to bring the nuclear age to a close, by shifting investments towards energy efficiency, and redoubling efforts to harness safe and secure renewable energy sources.”

The report can be downloaded from:

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Both the Japanese authorities and the International Atomic Energy Agency (IAEA) class the Fukushima disaster as INES level 5, an accident with ‘wider consequences’. The rating follows three main criteria areas: offsite radiological effects, onsite radiological effects, impairment of safety measures. For accidents (level 4 – 7) the radiological effects outside the plant are primarily relevant.

The Chernobyl accident involved one nuclear reactor; Fukushima has suffered major failures at four. Dr Hirsch’s study found if all of the releases from the Fukushima/Daiichi reactors are considered in total, this would equate to three INES level 7 events. 

An accident should be scaled level 7 if the releases add up to more than a couple of 10,000 TBq Iodine-131 equivalents. Conservative estimates by the French Institut de Radioprotection et de Sûreté Nucléaire (IRSN) show a release of 90,000 TBq I-131 en 10,000 TBq Cs-137 until the 22nd of March.

The release of Cs-137 should be multiplied by a factor 40 to get Iodine-131 equivalents. This means that the total releases add up to 500,000 TBq of Iodine-131 equivalents. Each reactor considered individually results in more than 100,000 TBq per block.