even if it does seem like a relatively easy way for terrorists to get thier hands on fissionable material

That problem can be worked around, fissionable material can be designed such that it can not be reprocessed to bomb grade material except at a nuclear processing facility. Basically you pick a packing material for the uranium such that they can't be easily separated, making it hard to increase the uranium purity to the point you could use it in a nuclear bomb.

A bigger problem is somebody taking the fissionable material and setting it on top of a massive conventional bomb, turning the explosion into an environmental disaster.

I have to wonder some times why people keep suggesting the idea of small scale nuclear power plants. There is no way such a thing could actually be made safe, and even if it could there is no way you could ever convince the public at large to accept it.

Jay