Nuclear Holocaust is a bit sensational. Sometimes people get a bit carried away with Nuclear technology, and its easy to create a nice over the top image in people's minds, because with the two bombs in Japan and reactor failure in Chernobyl, there is plenty to conjure up the imagination. Yes there is a threat, but we need be a bit balanced about it all. The chances of a nutter, getting the top of a reactor, are quite slim, however as is pointed out, the weak point is the fuel cycle, and this is indeed what needs tightening up, both in terms of fuel in and fuel out. The reality is very much a dirty, poisoning scenario, rather than a nuclear event. However, this poisoning could be effected by materials much easier to get hold of than fuel, from a reactor cycle. So the bottom line here is that going after nuclear material, would be much harder than getting the same evil result by other means. As humans naturally go for the easiest route, we ought to consider detection of other routes as the most likely mode of operation. I am not saying be careless, or not to act, to minimise the nuclear risk, I am just saying, keep your eyes on all the balls, and form a model that will help identify and prevent threats not envisaged. Like stopping continually undermining other nations and cultures could get results, almost straight away, and reduce risks substantially.