The containment building blew so there's been open release. And they haven't been able to keep it sprayed. So i dunno, see where it goes.
http://bravenewclimate.com/
"There appears to have been some exposure of this spent fuel, and radiation levels around this area remain high — making access in order to maintain water levels particularly troublesome. Note that apart from short-lived fission product gases, these radiation sources are otherwise contained within the rods and not particularised in a way that facilitates dispersion. Again, the problems encountered here can be linked to the critical lack of on-site power, with the mains grid still being out of action. As a further precaution, TEPCO is considering spraying the pool with boric acid to minimise the probability of ‘prompt criticality’ events. This is the news item we should be watching most closely today."