Why the Breeder Comes First
The breeder reaches useful output on fusion gain alone; the burner must clear net electric, a harder bar — so the breeder is built first.
Two machines, two thresholds
Kronos develops a breeder (Hyperion), a compact D-T spherical tokamak, and a burner (Aegis / MetroVolt), a D-³He tandem-mirror generator. They differ in what each must demonstrate before delivering value, and that difference sets the build order.
The breeder’s product is material: a tritium-class output near 4 kg/yr, a helium-3 coproduct near 1.97 kg/yr, and 14 MeV neutrons. Delivering those needs fusion gain (Q_sci 3.424, 88.7 MW fusion power) — not net electricity. The burner’s product is electricity, which requires net electric output: gross power minus everything recirculated to magnets, heating, and cryogenics must stay positive. That is the harder threshold.
Risk retired in order
Building the breeder first retires shared risk — high-field magnets, cryogenics, tritium handling, plasma control, and construction — before the burner attempts the harder net-electric goal. It also produces the helium-3 coproduct relevant to D-³He fuel.
- Breeder: value on gain; first construction risk carried here.
- Burner: value on net electric; sequenced after breeder de-risking.
- Shared learning: magnets, cryo, controls, and manufacturing transfer forward.
MetroVolt therefore matures in simulation and design while the breeder is built, ready for a test unit once the breeder has proven the foundations.