Also some great info at the Union of Concerned Scientists site, including this graphic of the containment system at the Fukushima reactor: All Things Nuclear Insights on Science and Security http://allthingsnuclear.org/tagged/Japan_nuclear?utm_source=SP&utm_medium=head&utm_campaign=sp-nuke-head-3%2F13%2F2011-pm images.investorshub.advfn.com/images/uploads/2011/3/15/[xncstumblr_lhzb23MSpu1qbnrqd.jpg