Deuterium is stable. Tritium has a half-life of 12.3 years. Like all proposed fusion reactors, you have to feed fuel in constantly rather than firing it up with

Deuterium is stable. Tritium has a half-life of 12.3 years. Like all proposed fusion reactors, you have to feed fuel in constantly rather than firing it up with a critical mass in situ, but you could store enough Tritium to run an aircraft carrier for a year in a smallish liquid gas cannister. (Smallish by aircraft carrier fuel tank standards.) ((With lead shielding. Lots of lead shielding. Tritium belts out about 9650 Curies of radiation per gram in the shape of beta radiation, which is enough to kill you really quick if you get it on or in you.))