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Tuesday, 2 August 2011

Awesome post on latest developments 3-8-11

...
photo(a) Will the man in this picture die in the next two weeks?  If the caption on the photograph is to be believed, then the answer is, “maybe, maybe not.” He is holding a radiation monitor mounted on a boom.  The boom appears to be three times his height.  Assume he is two meters tall (a conservative assumption).  Then he is standing approximately six meters from a radiation source of at least 10 Sieverts per hour.  (According to TEPCO, the monitor cannot register levels above 10 Sieverts per hour and was maxed out.)  Radiation like this goes in all directions, and decreases in intensity inversely proportional to the distance.  10 Sv/ hour divided by 36 yields an approximate dose of 280 mSv / hour.  The man is not walking away.  Let’s say he stood there for 1 minute or less; now the dose he received would be something like 4-5 mSv total.  TEPCO reports that the workers who found the new hot spot received only 4 mSv.  That is not a dangerous dose, but I have to say that this appears to be either extremely lucky or a lie.  The photographer took this picture, why?  Because they photograph everything they do?  No, more likely because this was an extraordinary finding that was being documented.  It takes time to recognize and document an extraordinary moment.  As I have posted before, most of the thousands of workers TEPCO has cycled through are not particularly well-trained (some working at the site were homeless before the earthquake/tsunami, trying to make ends meet by taking short-term, dangerous contract work at the nuclear power station).  I would be really surprised if the man in the photo stood there for only 1 minute.  Assume it was 20 minutes.  Also, I doubt that he is six meters away from the source.  More likely, he was something like 3 meters away.  Finally, the monitor maxed out at 10 Sv / hour.  We have no idea how much stronger the actual source is.  What if it were 4 times stronger?  If those assumptions were correct, then the exposure would have been 4 x 4 x 20 times greater, or 1.5 Sv.  At this level of gamma exposure, recovery would be expected (with treatment).  If he stood there for an hour, death would be expected (even with treatment).  So, probably he will live but I have a very hard time accepting the TEPCO estimate which implies he hustled away from the scene in the photo after about a minute.  It could be true!  However, TEPCO also acknowledges that this finding of the highest levels of radiation onsite since the earthquake are at “a level that could lead to incapacitation or death after just several seconds of exposure.”....

http://my.firedoglake.com/lobster/2011/08/02/new-developments-in-fukushima/
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