What is 3He
Helium-3 is a light, non-radioactive isotope of helium with two protons and one neutron. Its hypothetical existence was first proposed in 1934 by the Australian nuclear physicist Mark Oliphant while he was working at the University of Cambridge Cavendish Laboratory.
Because of its low atomic mass of 3.02 atomic mass units, helium-3 has some physical properties different from those of helium-4, with a mass of 4.00 atomic mass units. Because of the weak, induced dipole–dipole interaction between the helium atoms, their microscopic physical properties are mainly determined by their zero-point energy.
The appeal of helium-3 fusion stems from the aneutronic nature of its reaction products. Helium-3 itself is non-radioactive
Helium-3 boils at 3.19 K compared with helium-4 at 4.23 K and has less than half the density of Helium-4 when it is at its boiling point.
helium-3 and deuterium as the fuels in "aneutronic" (power without neutrons) fusion reactors. The involved nuclear reaction here when helium-3 and deuterium fuse creates normal helium and a proton, which wastes less energy and is easier to contain. Nuclear fusion reactors using helium-3 could therefore provide a highly efficient form of nuclear power with virtually no waste and no radiation.