Helium-3 from Tritium Decay

Helium-3 is produced not directly in the plasma but by the beta decay of bred tritium; the ~1.97 kg/yr coproduct depends on the tritium inventory.

A coproduct, not a plasma product

Helium-3 is not made in the D-T reaction. It appears because tritium is unstable: tritium beta-decays to helium-3 with a half-life of about 12.3 years. Any tritium that is bred and stored steadily converts a fraction of itself into helium-3, which can be separated and collected. The helium-3 coproduct, near 1.97 kg/yr, is therefore downstream of breeding, not of the plasma directly.

This coupling matters. Helium-3 yield depends on the tritium inventory held and how long it is held, which ties the coproduct to the breeding performance and to the tritium-management strategy. A machine that breeds and stores more tritium generates more helium-3 over time; one struggling toward self-sufficiency has less to spare for decay harvesting.

Why the coproduct is strategic

Helium-3 has no significant natural terrestrial source, and demand for it in cryogenics and quantum-computing infrastructure has no easy supply. A breeder that produces helium-3 as a decay coproduct offers a route to that isotope. The ~1.97 kg/yr figure is a design-and-simulation projection contingent on the breeding case, and it inherits the same open questions as the tritium numbers it depends on.

• Helium-3 comes from tritium beta decay (~12.3 yr half-life)
• Yield depends on tritium inventory and how long it is held
• ~1.97 kg/yr projection, contingent on the breeding case

This page describes a design-and-simulation study, not a built machine. Construction begins Q2 2027; first-of-a-kind first tritium is targeted near 2030. No hardware net-gain is claimed before FOAK.