Tritium Burnup Fraction

The plasma burns only a small fraction of the tritium fed to it per pass; the rest is pumped, cleaned, and recycled — which shapes the fuel loop.

Most tritium is recycled, not burned

A common misconception is that all tritium injected into the plasma fuses. It does not. Only a few percent of the tritium fed to the plasma actually reacts on a single pass; the large majority is exhausted unburned, pumped out of the vessel, separated from helium ash and impurities, and re-injected.

This low single-pass burnup fraction has two consequences for what Hyperion makes. First, the fuel-processing plant must handle a tritium throughput far larger than the net amount burned, which drives the size and speed of the tritium plant. Second, tritium spends time in walls, pumps, and processing lines — holdup — where some is lost to decay and permeation.

Burnup vs breeding

Net tritium balance is what is bred minus what is burned minus what is lost. Because burnup per pass is small, the dominant tritium consumer is not the fusion reaction directly but the accumulated inventory locked in the loop and lost to decay and holdup over time. Breeding must cover all of it.

Why it matters for products

• Large recycled throughput sizes the tritium plant
• Holdup in the loop is tritium unavailable for offtake
• Fast, efficient recycling reduces standing inventory and loss
• Burnup and breeding together set the net surplus

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.