@tal Definitely. A functional fission device is a major technical challenge, even for the most developed countries. A dirty bomb is much easier, and much more likely.

But, the real world is not a game, and powers that could do that almost certainly know it would not be worth it.

The real fear is of fringe terrorists groups doing it, because they're not as likely to be sensible about it, and some of them are crazy extremists who think some god is on their side.