These are websites which are developing nuclear breeder reactors:
The TAP MSR molten salt moderated by zirconium hydride.
IMSR A family of molten salt reactor designs
ARC-100 A descendant of the Integral Fast Reactor cancelled by stupidity in 1994. This is a fast neutron reactor, intrinsically capable of being refueled by natural or even depleted uranium.
All three are meltdown immune, very low waste, short lived waste, small physical footprint, tiny fuel quantity per MW-year.