Experimental release of 131I: the Green Run.

In December 1949, a large amount of 131I was released to the air at Hanford during the dissolving of irradiated uranium fuel for a classified military experiment called the "Green Run." Reports of the release have varied from about 0.15-0.3 PBq. Using, as a guide, the reported measurements of 133Xe released during the experiment, the amount of 131I released has been reanalyzed. The results indicate that about 0.40 +/- 0.12 PBq (11 +/- 3 kCi) was released, somewhat larger than the largest previous estimates.