Aren't breeder reactors mostly still on the drawing board? I get that they're very promising, but my understanding is that there remain some non-trivial issues to work out around corrosion and so on.

Anyway, I'm totally a believer in nuclear power for a greener future (yay Michael Schellenberger), but we need to keep these discussions honest: the path forward is to right now be building hundreds of copy-paste instances of existing, proven designs, not making the discussion about what might be possible with technology that's in development or not really in use at scale.