This is a bit nit-picky, but a CANDU reactor does not fission U-238. Neutrons in a CANDU reactor are still thermal neutrons, and if you put pure U-238 in a CAND

This is a bit nit-picky, but a CANDU reactor does not fission U-238. Neutrons in a CANDU reactor are still thermal neutrons, and if you put pure U-238 in a CANDU reactor it won't run. A CANDU reactor does run on uranium with a lower amount of U-235 than a standard PWR design, and it does transmute some of that U-238 into Pu-239 which it then does fission, but it doesn't directly fission U-238 and it does require some baseline ratio of U-235 to operate.