Deuterium from Water
Deuterium, a fuel for both machines, is separated from ordinary water and is effectively unlimited at any plausible deployment scale.
Deuterium is a heavy isotope of hydrogen and a primary fuel for both the D-T breeder (Hyperion) and the D-3He burner (Aegis / MetroVolt). It occurs naturally in ordinary water — a small, fixed fraction of all hydrogen — and is separated by established industrial processes. For the resource question, deuterium is effectively unlimited.
Scale of the resource
Every liter of water contains deuterium. The fraction is small per liter, but the total in the world's water is enormous relative to any conceivable fusion deployment. There is no mining, no depletion concern, and no geopolitically concentrated deposit. This is one of the strongest, most defensible resource claims in fusion.
Honest framing across the fuels
- Deuterium: abundant in water, no supply constraint.
- The water used to source deuterium is negligible against the water discussion elsewhere on this site.
- Tritium for the breeder is bred in the lithium blanket, not mined.
- Helium-3 for the burner is the genuine supply constraint, treated on its own page.
The defensible statement is unambiguous: deuterium is an effectively unlimited fuel drawn from water, with no meaningful resource or water penalty for its extraction. This is the easy end of the fusion fuel-resource spectrum; the hard end is helium-3.
It is worth closing the loop with the water discussion elsewhere on this site: the water consumed to extract deuterium is negligible against a plant's operational cooling water, and vanishingly small against the world's water resource. So deuterium is not only an unlimited fuel, it carries no meaningful water penalty in its sourcing — a rare case where a resource is both abundant and cheap to obtain in environmental terms.