Helium-3

Helium-3 is a rare, light helium isotope and the second half of Kronos's D–³He fuel — bred in situ rather than mined.

Symbol

³He

Nucleus

2 protons + 1 neutron

Terrestrial supply

Scarce (tritium decay); thin market

Kronos source

Bred in situ via catalyzed D–D

Helium-3 is a light, stable isotope of helium with two protons and one neutron. It is the prize fuel of low-neutron fusion because the deuterium–helium-3 reaction releases its energy as charged particles a direct-energy converter can capture, with no primary neutron.

The catch is supply: terrestrial ³He is scarce, sourced mainly from the decay of tritium, and the market is thin. Kronos handles this at the level of the fuel cycle, not the market — a staged, catalyzed D–D process breeds much of the plant's ³He in situ. Lunar regolith ³He is a long-horizon complement, not a requirement.