In-Situ Helium-3

Helium-3 arises in the machine from tritium decay and blanket reactions, a coproduct of the breeder alongside its tritium class output.

A valuable coproduct

Beyond its tritium output, Hyperion produces helium-3, roughly 1.97 kg/yr in the design point. Helium-3 is scarce on Earth and prized for cryogenics, quantum systems, medical uses, and, in the longer term, as the fuel the D-3He burner will consume. For the breeder it is a coproduct that emerges from the same neutron economy that breeds tritium.

Where it comes from

Tritium is radioactive and decays into helium-3 with a half-life of about twelve years. Tritium held in inventory and in the fuel loop therefore continuously generates helium-3, which can be collected during purification. This decay pathway ties the helium-3 output directly to the tritium the machine breeds and holds, making the two products physically linked.

Why it matters strategically

The burner (Aegis / MetroVolt) runs on D-3He, and its helium-3 demand at commercial scale is far beyond any terrestrial supply. A breeder that generates helium-3 as a coproduct is one piece of addressing that gap, alongside lunar sources. The ~1.97 kg/yr figure is a design and validation value tied to the breeder's operation, and the helium-3 accounting shares the same open questions as tritium inventory and extraction.

• ~1.97 kg/yr helium-3 as a breeder coproduct
• Arises mainly from tritium decay (12-year half-life)
• Strategically relevant to the future D-3He burner fuel gap

Construction begins Q2 2027; first-of-a-kind first tritium is targeted near 2030.