One rather interesting fact: I went to U of Illinois and have actually seen the room in the basement of the Met and Mining building (now Materials Science Building) where this Pu research was done. It is for real. A cinder block wall has been built around the original door, and a heavy steel door sits in it, sealed tightly. It was opened by DOE testers wearing radiation suits in 1996, two years before I got there, and one of my friends got to go inside (with the proper gear, of course). He said it wasn't anything interesting, but the DOE guys went around with their Geiger counters, said that everything was still radioactively hot and closed off the room again.