How does fusion work?
Fusion releases energy when the nuclei of two forms of Hydrogen (in our case, called Deuterium and Tritium) are collided together at such high velocities that they stick together or fuse. Shortly after this, they break apart, forming a neutron and a Helium nuclei and some net energy (mostly contained in the neutron). In a fusion powerplant, the neutrons will be used to heat water and drive a steam turbine. The fusion reaction is maintained as the Helium nuclei will help keep the remaining Deuterium and Tritium nuclei hot enough to keep fusing together.