Tritium Breeding Physics
Tritium is bred by capturing fusion neutrons in lithium: ⁶Li + n → T + ⁴He, with ⁷Li reactions adding tritium and a spare neutron.
Making the fuel from the product
Tritium does not exist naturally in useful amounts, so a D-T machine must breed its own. The mechanism is neutron capture in lithium. The dominant reaction, ⁶Li + n → T + ⁴He, is exothermic and works best with slower neutrons. A second channel, ⁷Li + n → T + ⁴He + n′, is a threshold reaction that consumes a fast neutron but returns a slower one — breeding tritium while multiplying neutrons.
The blanket surrounding the plasma is engineered around these reactions: it slows some neutrons to favor ⁶Li capture, uses ⁷Li and neutron multipliers to conserve the neutron population, and captures the tritium produced. The breeder's whole product logic rests on this being efficient enough.
The number that summarizes it
Breeding efficiency is captured in the tritium breeding ratio (TBR): tritium atoms bred per tritium atom burned. TBR above 1 is required for self-sufficiency, with margin for decay and losses. Hyperion treats TBR as a design lever across 1.1, 1.5, and 1.8 rather than asserting a single value, because the achievable ratio depends on blanket coverage, materials, and geometry that are still being resolved.
- ⁶Li + n → T + ⁴He: the main breeding channel
- ⁷Li + n → T + ⁴He + n′: breeds and multiplies neutrons
- TBR = bred / burned; treated as a lever (1.1 / 1.5 / 1.8)
Construction begins Q2 2027; first-of-a-kind first tritium is targeted near 2030. No hardware net-gain is claimed before FOAK.
