Friday, December 6, 2013

#Fukushima I Nuke Plant: TEPCO Estimates 25 Sieverts/Hour Radiation at the Bottom of Exhaust Stack for Reactors 1 and 2

Let's get back to Fukushima I Nuclear Power Plant, which feels to be working much better than the National Diet in Tokyo if you don't look very carefully.

Remember the exhaust stack between Reactor 1 and Reactor 2, the bottom of which was found in August 2011 to be emitting extremely high radiation? In fact, it was so high that the dosimeter went overscale at 10 SIEVERTS/Hour on the surface of the pipe (see my post from August 2, 2011).

TEPCO finally did the measurement on November 22, 2013 to find out how high.

The conclusion is that it may be as high as 25 sieverts/hour on the surface of the radiation sources, which TEPCO thinks two (see the above gamma camera photo).

The ambient air dose rates near the location were so high that the measurement was done with what looks like a 20-foot pole.

From TEPCO's Photos and Videos Library, 12/6/2013 (Japanese):

There are reports by the media and blogs that this 25 sieverts/hour radiation was actually measured. It wasn't. TEPCO measured the ambient air dose rates around the two locations where TEPCO thinks the radiation sources exist, and calculated the possible radiation level right at the radiation source.

The highest ambient air dose rate measured was 95 millisieverts/hour, at 1.5 meter from where the STGS (standby gas treatment) pipe is connected to the exhaust stack:

(From TEPCO)