@dalias @dave
There is no way nuclear of any sort is ever practical in a world without centralized power backed by threat of violence.
I disagree, here's one sort: nuclear batteries.
They don't require anywhere near the same kind of extraction and do have practical application without mass violence (low power applications in offgrid sunless areas).
Besides, uranium requires some extractivism and cannot (easily) work at scale without states, but that's also with current mining options. It is pretty abundant in the sea overall.
Fusion, if one ever manages to stabilize it, has various material options that aren't particularly rare. (And some that on the contrary are absurdly rare.)