The fusion of deuterium and tritium nuclei, producing helium-4 and a 14.1 MeV neutron — the most accessible and widely pursued path to net fusion energy.
The total energy release is 17.6 MeV per reaction. The alpha particle deposits its energy back into the plasma (self-heating). The neutron escapes and deposits energy in the blanket structure.[1]
Among all known fusion reactions, D–T has the highest reactivity at the lowest temperature. Its cross-section peaks near 64 keV, and the thermal reaction rate is already substantial at 10–20 keV. This is why virtually all near-term fusion devices are based on the D–T cycle.[1]
The 14.1 MeV neutrons cause displacement damage and transmutation in structural materials. First-wall components must withstand 10–20 dpa per full-power year. Materials qualification remains a significant open challenge.[2]
Tritium is radioactive (half-life 12.32 years) with a global inventory of roughly 20–25 kg. A D–T fusion power plant must breed its own tritium in a lithium-containing blanket:[2]
Most blanket designs target a TBR of 1.05–1.15 for fuel self-sufficiency.[2]
JET achieved 59 MJ of sustained fusion energy in its 2021–2022 campaigns. ITER is designed to demonstrate Q ≥ 10 in a D–T plasma.[3]