Tritium and Tritium breeding
With deuterium, the second isotope of hydrogen, containing one proton and two neutrons in the nucleus. Tritium does not occur naturally, because it is unstable to radioactive decay with a half-time of approximately 12 years. As deuterium and tritium represent the fuel in future power plants, a special tritium handling technology is required.
Since tritium is practically non-existent in nature, a fusion power plant has to breed its own tritium using a reaction between the neutron produced in the fusion reaction and the light metal lithium, which generates one tritium and one helium nucleus.
The breeding process will take place in the blankets, which form the vessel wall.