Richard wrote:



I seem to remember that it takes more material to build a reactor than a
bomb...
Yes, typically TONS of low-enriched Uranium for a light water
moderated reactor. There are some gadgets called water boilers
that used really small amounts of dissolved uranium and would go
critical on a few kg of it. They made wide pans to store it,
and sucked it up into a spherical chamber to make it go critical.
If it ever overheated, it would boil off some of the water
and drive the fluid back into the wide pan. Well, I'm pretty
sure nobody could get one of these licensed to operate today!

Jon