Comment Re: Thorium (Score 1) 272
So much wrong and misleading in three short statements. Oh dear.
U-238 is bred up into Pu-239 in most fission reactors, a lot of that is fissioned in turn during the fuel cycle, some Pu-239 remains when the reactor is shut down for refuelling, inspection or maintenance. The extra fission is a small bonus energy-wise, maybe one or two percent of total output and exceeded by the energy from the radioactive decay of fission products which is several percent of the total energy production.
Depleted uranium, mostly U-238 is non-fissile. No reactor will operate with a fuel load of U-238.
The CANDU reactors at Bruce in Ontario and elsewhere are heavy-water reactors and CAN run with unenriched uranium (ca. 0.6% U-235). They cannot and do not run on depleted uranium (ca. 0.1% U-235 or less). In fact most if not all CANDUs use slightly enriched uranium since it is more cost-efficient to do so.