Luminous paint paint was used to illuminate Apollo Lunar Module electrical switch tips and painted on control panels of the Lunar Roving Vehicle. The latest generation of the radioluminescent materials is based on tritium, a radioactive isotope of hydrogen with half-life of 12.32 years that emits very low-energy beta radiation. The devices are similar to a fluorescent tube in construction, as they consist of a hermetically sealed (usually borosilicate-glass) tube, coated inside with a phosphor, and filled with tritium. They are known under many names – e.g. gaseous tritium light source (GTLS), traser, betalight. Tritium light sources are most often seen as
Tritium MeV. In comparison, the fusion of deuterium with tritium releases about 17.6 MeV of energy. For applications in proposed fusion energy reactors, such as ITER, pebbles consisting of lithium bearing ceramics including LiTiO and LiSiO, are being developed for tritium breeding within a helium cooled pebble bed (HCPB), also known as a breeder blanket. High-energy neutrons can also produce tritium from lithium-7 in an endothermic (net heat consuming) reaction, consuming 2.466 MeV. This was discovered when the 1954 Castle Bravo nuclear test produced an unexpectedly high yield. High-energy neutrons irradiating boron-10 will also occasionally produce tritium: A more common result