Collecting Helium-3 from Decay

Helium-3 is separated from stored tritium during routine processing; because it is inert and unabsorbed, it collects as a gas ready for purification.

Harvesting the daughter

Helium-3 collection is a separation task, not a production task — the atoms are already being made by decay inside the stored tritium. The job is to remove the accumulated helium-3 cleanly, both to harvest the product and to keep the tritium fuel pure.

This is comparatively straightforward because helium-3 is chemically inert and is not absorbed by the metal-hydride getter beds that store tritium. As tritium decays on a bed, helium-3 collects as a free gas in the headspace and can be pumped off. Any helium-3 mixed with tritium gas is separated by the isotope-separation system, exploiting the mass and chemical differences between inert helium and reactive hydrogen isotopes.

The collection cycle

• Tritium decays on getter beds and in the fuel loop
• Inert He-3 accumulates as a non-absorbed gas
• Periodic pump-off removes He-3 from storage headspace
• Isotope separation strips He-3 from tritium gas streams
• Collected He-3 is purified and assayed to grade

Coupling to inventory

How much helium-3 is collected per year depends directly on how much tritium is held and for how long — the inventory-management choice. The ~1.97 kg/yr figure reflects the reference inventory. Collection efficiency and cadence, part of the design and validation program, set how much of the decayed helium-3 is actually recovered as product.

Construction begins Q2 2027; first-of-a-kind (FOAK) first tritium is targeted near 2030. No net-gain claim is made before FOAK.