General view of the Tokamak Fusion Test Reactor (TFTR) at Princeton plasma physics laboratory, New Jersey, USA, a device used to investigate energy generation through nuclear fusion reactions in a high-temperature plasma confined by a system of electromagnets. The plasma, a heated gas containing a mixture of nuclei and electrons, must be confined and compressed for sufficient time for the initiation of the nuclear fusion process. Nuclei of Tritium and Deuterium (isotopes of hydrogen) are used in such reactors, fusing, in theory, to give a helium atom, a free neutron and a vast amount of energy.