Tritium and the National Stockpile

Tritium is a short-lived radioactive gas the national stockpile must continually replenish; the breeder (Hyperion) is studied as a domestic make-up source.

Isotope

Tritium (hydrogen-3)

Half-life

~12.3 years

Annual decay

~5.5%/yr

Breeder output class

~4 kg/yr tritium

Why tritium is a recurring requirement

Tritium is the radioactive isotope of hydrogen, hydrogen-3, with a half-life of about 12.3 years. Unlike a stockpiled solid, tritium is a gas that decays continuously into helium-3 at roughly 5.5% per year. Any inventory that depends on tritium is therefore not a one-time purchase but a standing demand: material lost to decay must be made up on a schedule, indefinitely, for as long as the requirement exists.

Because tritium cannot be mined or stored indefinitely, a domestic production pathway is a matter of supply continuity. Historically, tritium has been produced by neutron irradiation in fission reactors. A fusion device offers a different route: the breeder (Hyperion) is a deuterium-tritium spherical tokamak studied to breed tritium in a lithium blanket while it operates.

Where the breeder fits

In the Kronos design studies, the breeder produces a tritium-class output on the order of ~4 kg/yr alongside helium-3 and 14 MeV neutrons. This page treats tritium strictly as a strategic and industrial isotope for domestic supply security; no weapons-design content is presented here, and none is required to make the supply-continuity point.

• Decay is the driver: ~5.5%/yr loss means demand never ends.
• Domestic production reduces exposure to single-source supply risk.
• The breeder co-produces tritium, helium-3, and neutrons from one platform.

Continuity, not a one-time buy

Because the requirement regenerates through physics, planning for tritium is a matter of continuity rather than acquisition. A single delivery ages out; only a dependable, appropriately sized production rate holds a level over decades. This reframes the question from 'how much do we have' to 'how fast can we make it up', which is the frame the rest of this section adopts. The breeder is studied as one contributor to that rate, alongside existing production, so that no single facility or route carries the whole burden of a self-renewing demand.

The remainder of this section walks through decay and inventory management, breeding in the blanket, extraction and handling, accountancy, and the honest gates that separate a computed design target from a delivered product.