Just adding some context here that I think a lot of other comments miss, but the envivonmental movement is often anti-nuclear because it's seen as not progressing passed our system's current extraction based economy.

Naomi Klein's "This Changes Everything" probably makes this case most clearly, arguing nuclear uses finite resources, creates waste and is damaging to mine.

I'm not arguing for this case here, but that view is very popular in environmentalist circles and probably explains why nuclear is absent from solarpunk literature.