Deuterium is just an isotope of hydrogen, as is tritium. While regular hydrogen has a proton and an electron, deuterium has a proton, an electron, and a neutron. Tritium has two neutrons, a proton, and an electron. Amazing how a single extra neutron per atom can turn dihydrogen oxide deadly.
Wait... what's the difference between tritium and pure tritium? In-game, DEUT is actually deuterium oxide, so having pure DEUT makes sense, but tritium is an element. How can it be any more pure? And what would be the difference in properties of pure tritium and normal tritium?
Tritium needs to decay into electrons.