Helium-3 from Tritium Decay
Every year, about 5.5% of a tritium inventory becomes helium-3; recovering it turns a decay loss into a strategic detection isotope.
- Source
- Tritium beta decay
- Rate
- ~5.5%/yr of tritium
- Product
- Helium-3, stable
Decay as a source
Tritium decays by emitting an electron and becoming helium-3. For the tritium account this is a loss of ~5.5%/yr; for helium-3 it is the primary source. The same physics that forces continuous tritium make-up steadily generates helium-3 that can be recovered from storage systems.
Recovery in practice
Helium-3 accumulates in getter beds and storage vessels as their tritium ages. Periodic recovery removes the accumulated helium-3 both to reclaim a valuable product and to keep it from interfering with tritium storage performance. What is a maintenance step for tritium is a production step for helium-3.
- Decay converts ~5.5%/yr of tritium into helium-3.
- Getter beds and vessels accumulate the daughter product.
- Periodic recovery yields a purifiable helium-3 product.
Turning a loss into a product
The most useful way to view decay-sourced helium-3 is as reclaimed value. The ~5.5%/yr lost from the tritium account is unavoidable; the only choice is whether the resulting helium-3 is captured or discarded. Recovering it from getter beds and vessels converts an inescapable loss into a strategic product and, at the same time, maintains storage performance by removing the accumulated daughter gas. This is why a platform that produces and holds tritium is naturally also a helium-3 source: the two products come from the same physics, harvested by the same maintenance step.
In the breeder design set, this decay-sourced helium-3 is part of the ~1.97 kg/yr co-production class. It reframes tritium decay: unavoidable for the tritium account, but a deliberate source for the helium-3 account. Both are reported as design-stage targets pending FOAK.