The Breeding-Ratio Lever

Hyperion treats the tritium breeding ratio as a design lever across 1.1, 1.5, and 1.8, spanning break-even to a surplus that seeds the fleet.

A lever, not a single value

The tritium breeding ratio (TBR) is the number of tritium atoms bred per tritium atom the plasma burns. Above one, the machine breeds a surplus; at one, it merely replaces what it uses. Rather than fix a single number, Hyperion treats TBR as a design lever evaluated at 1.1, 1.5, and 1.8, each representing a different balance of ambition and realism.

What each setting means

A TBR of 1.1 is close to self-replacement with little to spare. A TBR of 1.5 breeds a working surplus. A TBR of 1.8 is the aspiration: enough surplus to supply tritium beyond the machine's own needs and to seed additional units as the fleet grows. Higher TBR demands more complete blanket coverage, better neutron economy, and fewer losses, so it is harder to achieve as designed.

The honest caveat

The higher settings, particularly 1.8, are targets, not demonstrated results. Idealized neutronics readily reach high TBR, but real machines lose neutrons to ports, heating penetrations, structure, and incomplete coverage. Reconciling the local breeding calculation with the net, whole-machine value is an open question, and the lever framing is deliberate: it states the ambition while keeping honest about what the first-of-a-kind machine still has to prove.

• TBR = tritium bred per tritium burned
• Lever values 1.1, 1.5, 1.8 span break-even to fleet-seeding
• The 1.8 target is not yet proven — an open reconciliation

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.