Vaporizing nuclear fuel is how we enrich it. Uranium => Uranium Hexaflouride sublimed at 57C => Gaseous centrifuge to separate the isotope. We've been doing it since the Manhattan Project, since before nuclear power plants were even a thing.
Comparing uranium hexafluoride vapor at 57 C to incandescent vaporized uranium + fission products at 22,000 C. The materials problems with the latter are just a bit more severe!
https://en.wikipedia.org/wiki/Enriched_uranium#Centrifuge_te...