<Dd> H + He → p (14.68 MeV) + He (3.67 MeV) </Dd> <P> Third - generation fusion fuels produce only charged particles in the primary reactions, and side reactions are relatively unimportant . Since a very small amount of neutrons is produced, there would be little induced radioactivity in the walls of the fusion chamber . This is often seen as the end goal of fusion research . He has the highest Maxwellian reactivity of any 3rd generation fusion fuel . However, there are no significant natural sources of this substance on Earth . </P> <Dl> <Dd> He + He → 2 p + He (12.86 MeV) </Dd> </Dl> <Dd> He + He → 2 p + He (12.86 MeV) </Dd>

Which of the following is the most common fuel for nuclear fission