You're conflating fissile and fertile again. A CANDU cannot run on thorium as thorium doesn't fission. It can run on U233 or U235 or plutonium at low concentrat

You're conflating fissile and fertile again. A CANDU cannot run on thorium as thorium doesn't fission. It can run on U233 or U235 or plutonium at low concentration, and it can theoretically breed U233 over unity, but noone has tried. Just as noone has run a breeder reactor on fuel bred in a breeder reactor and extracted. Neither can be done without reprocessing capable of at least temporarily extracting weapons grade material. Expansion of nuclear power to more than an insignificant amount will reduce those 100 years to a decade or two. Nuclear is irrelevant to decarbonization on a world scale, any effort spent building burner reactors is a waste of resources that could do twice as much elsewhere.