There's quite a bit of misleading info in some news reporting making numeric comparisons between numbers representing different types of data (activity totals versus exposure rates) and in some cases mismatching units too. At least there seems to be plenty of monitoring going on in Japan, and wide access to frequently updated data. NHK today was reporting the government website now has hour by hour values tabulated. I think that's to help people understand that the daily averages are mostly well below the peak values that get attention. Using a peak hourly rate value for a daily or longer calculation may cause people to over react. (Of course people may have other exposure through food, water etc.)

Studying two other incidents, one at a Japanese fuel facility in 1999 (closed in 2003) and the other with a U.S. army Idaho Falls (Dugway testing grounds) reactor that went critical in an accident in 1961 provides insight into the neutron-moderating behavior of water, and interesting case studies of exposure to people after the initial events. Less known than three mile island, both are significant.

https://secure.wikimedia.org/wikipedia/en/wiki/SL-1 https://secure.wikimedia.org/wikipedia/en/wiki/Tokaimura_nuc...

Except those flying out of Tokyo land eventually, thus they have a cap on their exposure.