Air Sampling Show Decline In Fukushima Fallout Output

Air Sampling Show Decline In Fukushima Fallout Output

this chart from http://www.galcit.caltech.edu/~jeshep/fukushima/ShepherdFukushima30Sept2011.pdf Caltech professor shows how various elements declined.  

Various flavors of I-133 have half-lives from 21 hr to 9 s and 170 ns, which explains why it dropped off so fast.

133I	53	80	132.907797(5)	20.8(1) h	β-	133Xe	7/2+
133m1I	1634.174(17) keV			9(2) s	IT	133I	(19/2-)
133m2I	1729.160(17) keV			~170 ns

cs-136 is 13 days

The good news is that the radiation really is declining. The bad news is that all the while it was declining, the fission was evidently continuing (at lower levels) and leaking just about everything all the time.