Helium-3 Purity and Separation
Detector-grade helium-3 must be separated from helium-4 and other gases and verified to specification before it can be used.
Why purity matters
Helium-3 recovered from tritium storage arrives mixed with other gases, including helium-4 and residual hydrogen isotopes. Detector performance depends on isotopic purity, so the recovered gas is separated and purified to a detector-grade specification and then assayed to confirm it meets requirements.
Separation methods
Because helium-3 and helium-4 differ only in mass, separation exploits that small difference through physical processes analogous to those used for hydrogen isotopes. The same class of separation capability that enriches tritium supports helium-3 purification, so a tritium platform is naturally equipped for both.
- Isotopic separation: helium-3 from helium-4 by mass difference.
- Chemical cleanup: remove residual hydrogen isotopes and contaminants.
- Assay: verify isotopic purity against detector-grade spec.
Design-stage figures
Shared separation infrastructure
A practical advantage of producing helium-3 on a tritium platform is that the demanding separation infrastructure already exists. The same class of systems that enriches tritium and separates it from ordinary hydrogen isotopes can separate helium-3 from helium-4 and remove residual contaminants to a detector-grade specification. Purification and assay then verify the product before release. Because the hardest capability is shared, adding helium-3 as a product does not require standing up an entirely separate purification chain, which is part of why co-production is efficient as well as strategically useful. The result is detector-grade material produced and verified within infrastructure the platform already needs for tritium.
For the breeder, purity targets are stated to established detector-grade practice, and the co-production capability leverages the same separation infrastructure used for tritium. Delivered purity is a FOAK-era result reported honestly rather than assumed in advance.