[jlgreco]

> The core material is the important part if you are, say, Iran or North Korea. However, if you are in a cave with a box of scraps and no Tony Stark, there's a lot more to it.

Similarly, I suspect that PALs have traditionally been designed with the first in mind. They prevent a proper detonation as the bomb as it currently exists. They seem less concerned with someone using the bomb to cobble together a (relatively speaking) inefficient bomb, or even just a dirty bomb.

If you are satisfied with merely dozens to hundreds dead, and a massive clusterfuck of a disproportionate response, you may have to do nothing more than merely trigger the PAL's anti-tampering mechanism in a populated area. Worse case scenario there is that it doesn't work that way, then you just throw it into a truck with some fertilizer and blow it up anyway.

Nations are not interested in using a bomb like that, they would want the real deal in a form factor that is practical for military use. PALs seem designed to prevent that.

[mikeash]

The possibility of taking an existing bomb and using it to build a new nuclear bomb without being an actual military is absurd. You'll not get an inefficient bomb, you'll get a dud.

Dirty bombs are a different threat altogether. One that's almost entirely psychological. No doubt effective at that, but a completely different scenario than the one being discussed.

[jlgreco]

It is fairly trivial to do with uranium, but with plutonium you are correct; you would never get anything beyond a fizzle (if you were lucky).

If the discussion is "what if terrorists steal a bomb", then the discussion is implicitly about dirty bombs. No other discussion really makes sense.