It's not like we're gonna create an environmental catastrophe on the moon. Nobody had problems when we scattered Beresheet on the moon, so I don't think a reactor is gonna make much difference, especially with all the unfiltered ionizing solar radiation hitting the surface.
It would be difficult to make the moon's surface MORE hostile than it already is to human life. Not impossible, just difficult.
Bringing earth fuels, nuclear or otherwise, to the moon seems backwards to me. If you really want something to be self sustaining, we need to find a power source accessible FROM the moon. Solar is going to be hyperefficient compared to Earth, but the problem is your days are two weeks long (nice), nights are also two weeks long (not so nice). I am not sure battery technology is both light enough to haul up there and has the capacity to run things during the dark fortnight.
not sure of the probability of finding uranium or thorium or other nuclear sources ON the moon, even if we did, not exactly gonna be easy to build a plant to refine them for use.
Something that MAY work would be if we could create giant greenhouses and grow biomass plants for energy. But pretty sure that burning them is gonna require oxygen that we don't yet have, and likely more oxygen than the plants would generate.
Curious if we could generate power from the differences in temperature on the moon, some spots must get pretty hot when in direct sunlight, while shadowed areas are cold. I did great in physics but it was a long time ago, seems like you ought to be able to generate power from a large heat differential, but I can't remember how it is done.