Nuclear fusion
Nuclear fusion is the fusing of light atomic nuclei to form heavier nuclei. Of all pairs of light atomic nuclei capable of fusing it is the reaction between the two heavy hydrogen isotopes, deuterium and tritium, that affords the greatest energy yield at the lowest temperature. One deuterium and one tritium nucleus fuse here to form a helium nucleus. A fast neutron is then released that carries eighty per cent of the energy gained (17,5 MeV).