3 ms·

The surrounding land is heavily contaminated with Cs-134 and Cs-137. http://i.imgur.com/xu0Pm.jpg http://i.imgur.com/xu0Pm.jpg http://www.mext.go.jp/component

by uvdiv 15y ago

The surrounding land is heavily contaminated with Cs-134 and Cs-137. http://i.imgur.com/xu0Pm.jpg http://i.imgur.com/xu0Pm.jpg http://www.mext.go.jp/component/english/__icsFiles/afieldfile/2011/05/10/1304797_0506.pdf http://www.mext.go.jp/component/english/__icsFiles/afieldfil... It will be a closed zone for decades. Almost all of the (external) dose in the area right now is from these two isotopes; the rest have decayed. (There's a model of this in [1]). These two will not decay away quickly; Cs-134 has a half life of 2 years, and Cs-137, 30 years. [1] http://www.rri.kyoto-u.ac.jp/NSRG/seminar/No110/Iitate-interim-report110404.pdf http://www.rri.kyoto-u.ac.jp/NSRG/seminar/No110/Iitate-inter...

ChuckMcM 15y ago
It will be a closed zone for decades. I believe you have misinterpreted the data. The highest measured readings were 91 uSv/hr. That is equivalent to 9.1 mRem/hr (1 mRem = 10 uSv). The lowest dose in the 'red' zone is 19 uSv/hr or 1.9mRem. Public safety is considered to be 'at risk' if you are exposed to > 1000 mRem over 4 days. You can't reach that level in places where they read 91 uSV/hr (best you can do is 9.1244 or 873.6 mRem/4 days. And where its only 1.9mRem you only get 182 mRem/4 days. The bottom line is that it is safe to go anywhere in the current 80km radius circle, if you are the government and want to minimize radiological hazard you will go through the area that shows the highest activity and identify and clean up any hot spots. That information btw is in the DoE's contribution to this report. The second part you missed is that Cs-134 will be down to noise in less than a decade due to decay which will reduce overall dosage. (I've noticed that no one has published the ratio) So is there contamination from the plant in Japan? Yes. Does is pose a public health risk? For the most part no. Will any part of the area be 'off limits' this time next year? Probably not. Will monitoring continue and specific areas be targeted for decontamination? Almost certainly.

by uvdiv 15y ago

ChuckMcM 15y ago

It will be a closed zone for decades. I believe you have misinterpreted the data. The highest measured readings were 91 uSv/hr. That is equivalent to 9.1 mRem/hr (1 mRem = 10 uSv). The lowest dose in the 'red' zone is 19 uSv/hr or 1.9mRem. Public safety is considered to be 'at risk' if you are exposed to > 1000 mRem over 4 days. You can't reach that level in places where they read 91 uSV/hr (best you can do is 9.1244 or 873.6 mRem/4 days. And where its only 1.9mRem you only get 182 mRem/4 days. The bottom line is that it is safe to go anywhere in the current 80km radius circle, if you are the government and want to minimize radiological hazard you will go through the area that shows the highest activity and identify and clean up any hot spots. That information btw is in the DoE's contribution to this report. The second part you missed is that Cs-134 will be down to noise in less than a decade due to decay which will reduce overall dosage. (I've noticed that no one has published the ratio) So is there contamination from the plant in Japan? Yes. Does is pose a public health risk? For the most part no. Will any part of the area be 'off limits' this time next year? Probably not. Will monitoring continue and specific areas be targeted for decontamination? Almost certainly.