From what I can see: with Angel's Industries you have three different tiers of nuclear power: plutonium, thorium-plutonium and deuterium. Uranium is kind of only used to kickstart the plutonium varieties. But I never went deep into nuclear with Angel's and I don't touch the actual code of the mod, just relaying information.
Beware: which nuclear recipes from basegame or from Bob's mods are available depends in fact on mod combinations and mod settings.
When I asked your first question to the Angel's mods discord:
So yeah, having no recipe for the Kovarex process is intended. But maybe in the future the technology will not be entirely empty anymore.valneq: Angel's nuclear stuff is meant to be played without Kovarex, right?
pezzawinkle: Correct. Kovarex would break the concept entirely, and even the bobingabout one gets removed under some conditions