Viable fusion will need breeder reactors for tritium? "Old fission" isn't technically a viable economic power system anymore, at least in its current forms. So

Viable fusion will need breeder reactors for tritium? "Old fission" isn't technically a viable economic power system anymore, at least in its current forms. Solar/Wind are so cheap, and still getting percentages cheaper each year, that it gets harder and harder for other forms of power to compete. Even combined cycle natural gas turbine with downstream heat recapture to exceed Carnot efficiency limits can't compete with wind/solar. I get what you mean about viable fusion in just sustaining a energy-positive reaction. But even if that is achieved, fusion will likely not be economically viable outside of industrial high-heat constant-load applications (which there are a lot of, fission should be able to handle those but the waste and proliferation concerns are a real barrier). If there are breeder reactors needed for fuel ... forget viable grid fusion power.