While solar obviously would not work there, is there any compelling reason to need nuclear power in those permadark locations?
It's not that reactors are needed in the permadark regions, it's just they they tend to be very cold and it should be easier to dissipate heat from the reactor.
I thought that it's hard to radiate-away heat in vacuum?
Dump the heat into the ground.
I think there is reason on mars - there is a fairly significant source of water there (ice). I guess this wouldn’t explain the moon though.
The darker locations are co-located with the largest water ice deposits which are exciting for the possibility of a human presence.