Deuteriumtritium

Deuteriumtritium refers to the fusion reaction between the hydrogen isotopes deuterium (2H) and tritium (3H). The most studied form is D-T fusion, which produces a helium-4 nucleus (alpha particle) and a fast neutron: 2H + 3H → 4He + n. The total energy released per reaction is about 17.6 MeV, with the neutron carrying 14.1 MeV and the alpha particle about 3.5 MeV of kinetic energy. The high-energy neutron is a key consideration for reactor design, contributing to material heating and activation.

Deuterium is a stable, naturally occurring isotope of hydrogen, comprising about 0.015% of hydrogen in seawater. Tritium is radioactive with a half-life of about 12.3 years and does not occur freely in nature in meaningful quantities; it is produced in reactors or in fusion devices and can be bred in lithium-containing blankets around a reactor through neutron reactions with lithium.

D-T fusion is the leading candidate for practical controlled thermonuclear energy due to its relatively high reaction cross-section at achievable temperatures. In theory, it requires reaching temperatures on the order of tens of millions of kelvin and sufficient confinement time to satisfy the Lawson criterion. Two main approaches are pursued: magnetic confinement fusion, as in tokamaks and stellarators, and inertial confinement fusion, using powerful laser or other implosion methods. A successful D-T cycle typically involves breeding tritium in a blanket to maintain fuel supply, since tritium is scarce in nature and must be replenished.

Safety and environmental aspects center on handling tritium, a weak beta emitter, and managing neutron-induced activation of reactor materials. The technology remains under investigation with the aim of achieving net energy gain and practical fusion power.