The Deuterium-Tritium Reaction

D + T fuses to helium-4 plus a 14.1 MeV neutron, releasing 17.6 MeV total — the reaction with the most accessible fusion cross-section.

The reaction Hyperion runs

Hyperion fuses deuterium and tritium: D + T → ⁴He + n, releasing 17.6 MeV. The energy splits by momentum conservation into a 3.5 MeV alpha particle and a 14.1 MeV neutron. The alpha stays confined by the magnetic field and heats the plasma; the neutron escapes and carries the product energy into the blanket.

D-T is chosen because its fusion cross-section peaks at a lower temperature than any other candidate fuel, making it the reaction reachable with today's confinement. That is exactly why it is the breeder's fuel: the machine that has to work first uses the easiest reaction, and the neutron it produces is what breeds the fuel for everything after it.

The fuel-cycle consequence

Tritium does not occur naturally in useful quantities; it must be bred. The same 14 MeV neutron that carries the product energy is captured in a lithium blanket to breed new tritium via ⁶Li + n → T + ⁴He. The reaction is thus both the energy source and the seed of its own fuel cycle — which is why closing that cycle is a central open question for the design.

• 17.6 MeV per reaction: 14.1 MeV neutron + 3.5 MeV alpha
• Lowest-temperature fusion cross-section of the candidate fuels
• The product neutron also breeds the next batch of tritium

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.