NHK has just confirmed, an earlier report from Japan Today, that the Japanese government’s nuclear safety agency has decided to raise the Fukushima accident to Level 7, on the International Nuclear and Radiological Event Scale, or INES. NHK reports that the change will be announce at a press conference, tomorrow morning, Tuesday, April 12, 2011.
Japan Today reported earlier that the Japanese government was considering raising the International Nuclear Event Scale rating to 7, a level previously only reached by the 1986 Chernoby accident, based on a new report of the amounts of radiation released during the early days of the accident.
http://www3.nhk.or.jp/...
http://www.japantoday.com/...
Japan Today reports
The Nuclear Safety Commission of Japan released a preliminary calculation Monday saying that the crippled Fukushima Daiichi nuclear plant had been releasing up to 10,000 terabecquerels of radioactive materials per hour at some point after a massive quake and tsunami hit northeastern Japan on March 11.
The disclosure prompted the government to consider raising the accident’s severity level to 7, the worst on an international scale, from the current 5, government sources said. The level 7 on the International Nuclear Event Scale has only been applied to the 1986 Chernobyl catastrophe.
According to an evaluation by the INES, level 7 accidents correspond with a release into the external environment radioactive materials equal to more than tens of thousands terabecquerels of radioactive iodine 131. One terabecquerel equals 1 trillion becquerels. Haruki Madarame, chairman of the commission, which is a government panel, said it has estimated that the release of 10,000 terabecquerels of radioactive materials per hour continued for several hours.
This latest analysis is more consistent with the high levels of radiactive contamination across the surrounding area, and an expansion of the suggested evacuation area to 30 km, in selected areas. Today, the commission reports broader areas where radiation will cause residents to exceed annual limits, but stopped short of broadening the exclusion zones.
The commission says the release has since come down to under 1 terabecquerel per hour and said that it is still examining the total amount of radioactive materials released.
The commission also released a preliminary calculation for the cumulative amount of external exposure to radiation, saying it exceeded the yearly limit of 1 millisieverts in areas extending more than 60 kilometers to the northwest of the plant and about 40 km to the south-southwest of the plant.
It encompasses the cities of Fukushima, Date, Soma, Minamisoma, and Iwaki, which are all in Fukushima Prefecture, and some areas including the town of Hirono in the prefecture.
I still need to read the original reports, as the newspaper accounts, linked here, appear to be leaving the time units off of their reports of radiation levels.
If these reports turn out to be true, we can anticipate more areas to be designated for evacuation, soon, as several independent groups have been recommending.
In a separate report, the fire previoiusly reported this afternoon in unit four, has apparently been put out.
It should be noted, that this increase in the INES level to 7, is based on estimates that the original radiation releases were higher, than previously suspected, not on new releases, occuring now. They have nothing to do with today's reported fire, in unit 4.
Although, today's news is sad, for the Japanese people, it does represent an improvement in Japan's reporting transparency.
Update: Finally, the evacuation perimeters are being expanded to 30 km. But, we see reports in the Commission report of radiation exceeding annual limits up to 80 km, from the plant. I suspect, we will see additional expansions of this perimeter, soon.
Chief Cabinet Secretary Yukio Edano said Monday, residents in areas between 20 and 30 km around Fukushima would be advised to evacuate due to accumulated radiation exposure levels.
http://sg.news.yahoo.com/...