Back to my “hypothetical nuclear terrorism” reading, and some of the analyses have given me this impression.

So there are some ifs beyond the norm that actually make it more likely. Besides the usual “if you have the resources and personnel for the job”, there’s two things that make the job of the would-be nuclear terrorist easier and their opponents harder.

• Being willing to take the hit of large and likely fatal amounts of radiation during transportation and construction. This is pretty self-explanatory, especially when using comparably “fresh” (and thus high radiation) spent power reactor fuel as an input.
• Being willing to detonate the bomb in a target area closer to the assembly site, even if it’s less damaging and/or prestigious.

However, this narrows the personnel pool even more. It may be a slight narrowing, but it’s still a narrowing. It’s also worth noting that the first point makes a “factory accident” a lot more likely, perhaps countering the advantage of fanaticism.