7.3.3 Tritium in hydrogen bomb secondaries.Tritium is also used as a nuclear fusion fuel, along with more abundant deuterium, in tokamak reactors and in hydrogen bombs. It is used in a medical and scientific setting as a radioactive tracer. Tritium is used as the energy source in radioluminescent lights for watches, gun sights, numerous instruments and tools, and even novelty items such as self-illuminating key chains. It can be produced artificially by irradiating lithium metal or lithium-bearing ceramic pebbles in a nuclear reactor, and is a low-abundance byproduct in normal operations of nuclear reactors. The atmosphere has only trace amounts, formed by the interaction of its gases with cosmic rays. Naturally occurring tritium is extremely rare on Earth. The nucleus of tritium ( t, sometimes called a triton) contains one proton and two neutrons, whereas the nucleus of the common isotope hydrogen-1 ( protium) contains just one proton, and that of hydrogen-2 ( deuterium) contains one proton and one neutron. Tritium ( / ˈ t r ɪ t i ə m/ or / ˈ t r ɪ ʃ i ə m/, from Ancient Greek τρίτος (trítos) 'third') or hydrogen-3 (symbol T or 3H) is a rare and radioactive isotope of hydrogen.

Half life 3 beta