- You may also be looking for trititanium, tritanium or titanium.
Tritium was a basic atomic element, it is an isotope of hydrogen. Its nucleus consisted of a proton and two neutrons. Tritium, similar to deuterium, was used as fuel in matter-antimatter reactions aboard starships like the USS Enterprise-D. It was stored, with deuterium, in the deuterium tank. (TNG: "Booby Trap", okudagram; TNG: "Galaxy's Child")
Aboard the Galaxy-class USS Enterprise-D, in the Engineering Systems Database, there were folders titled Deuterium/Tritium Loading Procedures and Deuterium/Tritium Tankage Transfer and Safety. These folders contained technical manuals relevant to the topic. (TNG: "Booby Trap", okudagram)
In late 2375, tritium proved to be extremely important in helping the Federation Alliance to win the Dominion War. A Klingon chief engineer aboard the IKS Ki'tang adjusted the tritium intermix to compensate for a warp core containment problem. During the Second Battle of Chin'toka, the tritium made the ship invulnerable to the Breen energy dampening weapon. (DS9: "When It Rains...")