here are some real data (sorry, in german):

http://www.grs.de/informationen-zur-lage-den-japanischen-ker...

there was a peak at 1.2 mSv/h when the meltdown occured. All in all the values are in the range of 0.4-1 mSv/h. At least a factor 10 lower as I found in the approximation above.