The ~4 kg/yr Tritium Class

Hyperion's tritium output is quoted as a class near 4 kg/yr — a design figure set by the neutron budget and the achieved breeding ratio.

What sets the number

Tritium output is not a free parameter. It is bounded by how many 14 MeV neutrons the plasma produces and by how efficiently the blanket converts them to bred tritium. At 85.0 MW of fusion power the D–T neutron rate is fixed by physics; the conversion is the tritium breeding ratio (TBR).

The net tritium available for products equals what is bred, minus what the D–T plasma itself burns, minus decay and process losses. Because the plasma consumes tritium to run, only breeding above unity leaves a surplus. The ~4 kg/yr class describes the surplus target under the favorable breeding scenario.

Class, not a point number

Kronos states this as a class rather than a single guaranteed value because the realized output slides with the TBR lever (1.1 / 1.5 / 1.8), with lithium-6 enrichment, blanket coverage, and tritium holdup. Higher TBR and coverage push output up; ports, structure, and losses pull it down.

The dependence chain

• Fusion power 85.0 MW → neutron source rate (fixed)
• × net TBR → tritium bred per unit time
• − plasma burnup − decay − holdup → net surplus
• = ~4 kg/yr class (target scenario)

The figure is honest only if the net TBR and self-sufficiency gates close. Both are open at the 1.8 target and are treated as design-and-simulation findings, not demonstrated results.

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