Deuterium and tritium are both considered first-generation fusion fuels; they are the easiest to fuse, because the electrical charge on their nuclei is the lowest of all elements. The three most commonly cited nuclear reactions that could be used to generate energy are:
:H + H → n (14.07 MeV) + He (3.52 MeV)
:H + H → n (2.45 MeV) + He (0.82 MeV)
:H + H → p (3.02 MeV) + H (1.01 MeV)