Saturday, April 9, 2011

#Fukushima I Nuke Plant Accident May Be INES "Level 6"

Says Yomiuri Shinbun on April 10, while Asahi Shinbun said the same thing on March 25. It's a news to Yomiuri readers, old news to Asahi readers.

Expect an announcement from Nuclear and Industrial Safety Agency to follow this Yomiuri discovery soon.

The International Nuclear and Radiological Event Scale (INES) defines the severity of nuclear accidents. A Level 6 accident is a "Serious Accident".

The Chernobyl accident is the only Level 7 (Major Accident) accident so far, and the Three Mile Island accident is a Level 5 accident. On March 18, METI's Nuclear and Industrial Safety Agency announced its preliminary assessment that the Fukusima I Nuke Plant accident may be a Level 5 (Accident with Wider Consequences) accident, instead of Level 4 (Accident with Local Consequences) as the Agency had initially indicated.

Both Yomiuri and Asahi's news source was the Nuclear Safety Commission (which has, by the way, gone very very quiet).

The Nuclear Safety Commission calculated the amount of Iodine-131 released in the atmosphere from 6:00AM on March 12 till March 24 midnight, and came up with the number of between 30,000 to 110,000 terabecquerels. (tera=1 trillion)

Yomiuri says (taking the lower estimate) 30,000 terabecquerels mean "Level 6", defined as "few thousands to tens of thousands" of terabecquerels of radioactive iodine.

Asahi says that "the discharge of radioactive iodine at the Chernobyl accident was said to be about 1.8 million terabecquerels"

Asahi's article also points out that there are locations that have the high soil contamination as Chernobyl.

From Asahi Shinbun English version of their March 25 article:

Meanwhile, calculations of soil contamination by experts have already produced results that are at the same level as for Chernobyl.

Cesium-137 levels of 163,000 becquerels per kilogram of soil was detected in Iitate, Fukushima Prefecture, about 40 kilometers northwest of the Fukushima plant, on March 20. That was the highest figure in the prefecture.

According to Tetsuji Imanaka, an associate professor of nuclear engineering at the Kyoto University Research Reactor Institute, if the Iitate figure was converted to one square meter, the figure would be 3.26 million becquerels.

After the Chernobyl accident, residents who lived in regions with cesium levels of 550,000 becquerels ore more per square meter were forcibly moved elsewhere.

"Iitate has reached a contamination level in which evacuation is necessary," Imanaka said. "Radiation is still being released from the Fukushima plant. The areas of high contamination can be considered to be on par with Chernobyl."

Already, foreign institutions have been saying that the Fukushima I Nuke Plant accident may be or may become Level 7 (here and here).

And this Russian engineer predicts Fukushima will surpass Chernobyl, and INES needs a new scale.

Oh I forgot. That's "fear-mongering".


Anonymous said...

Here's a nice nuclear catastrophe map.

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