At one point there were probably in excess of 60,000 nuclear weapons worldwide. (We had 31,000 in the late ‘60’s.) Now, I’m certain that the ones the US had were dismantled. But, according to General Lebed, the man in charge of the Soviet nuclear production, the Soviets weren’t even certain how many they made. They weren’t serialized and different methods were used and the figures were lost. So, what happened to all those Soviet nukes? In short, they’re not sure. Lebed said he made 100 suitcase nukes for the KGB. When the Soviet Union fell he went to get them back and was told, “What nukes?”
So, for certain there are 100 small ones lose out there someplace. It only takes one guy with this man’s attitude to incinerate hundreds of thousands.
With Iran coming onboard, it will, at some point happen. Can you imagine that over the next 100 years it won’t? Fifty years? Ten years? 2016?
Actually there is some good news there. Nukes are more fragile than people realize, and especially don't do well over time. They have a number of componants that need to be fressh, and degrade fast. Nuke stockpiling is a difficult business even in the US. So just keeping a stolen nuke around for decades pretty much guarantees it's not going to be ready for prime time. Even the high explosive triggers might not work. I would guess that for this reason, if the stolen nukes weren't going to be used anytime soon, the plutonium was removed for sale on the global market, to be used in fresh nukes sometime in the future - as well as the high explosives, to be used elsewhere as well. But the original mechanisms would be tossed.