No, the five times number is per weight, not per reaction. Per reaction, the fusion one Deuterium and one Tritium yields 17.6 MeV [1]. The atomic mass of the co

No, the five times number is per weight, not per reaction. Per reaction, the fusion one Deuterium and one Tritium yields 17.6 MeV [1]. The atomic mass of the components is 5, so you get 3.5 MeV per one unit of atomic mass (also called a Dalton). Per reaction, fission produces between 190 and 200 MeV. Since the input is one nucleus of U-235 or Pu-239 and one neutron, the mass is either 236 or 240, so the yield is 0.8 MeV per Dalton. So the deuterium-tritium reaction is only 4.4 times more energetic than fission, per unit of mass. As for your first part, I didn't get what you were trying to say. > Breeder reactors are not some sort of perpetual-motion device. I don't think I implied they are, and I don't think anyone believes in perpetual-motion devices in 2024. [1] https://en.wikipedia.org/wiki/Nuclear_fusion#Criteria_and_candidates_for_terrestrial_reactions https://en.wikipedia.org/wiki/Nuclear_fusion#Criteria_and_ca...