Tritium Breeding Ratio (TBR)

Tritium atoms bred per tritium atom burned; must exceed 1 for self-sufficiency.

Because tritium is not available in nature, a D–T plant must breed its own. The tritium breeding ratio is the number of tritium atoms produced in the blanket per atom consumed in the plasma; a value above 1 (with margin) is required for a self-sustaining fuel cycle.

HYPERION targets TBR = 1.8, breeding 4.0 kg/yr against a startup inventory of 6.47 kg.

Since tritium is essentially absent in nature and decays with a ~12-year half-life, a D–T plant must breed its own or it cannot run. Lithium-6 is the key breeding isotope, often enriched, with a neutron multiplier added to reach the target ratio. HYPERION's TBR of 1.8 is designed to be self-sufficient and to export a surplus.