The Gain-Only Requirement

Hyperion must reach fusion gain to deliver its products; it does not need to cross the harder net-electric threshold.

Two different thresholds

Scientific gain (Q_sci) is the ratio of fusion power produced to heating power injected into the plasma. Engineering gain, or net electric, additionally requires that total plant electrical draw, magnets, cryoplant, heating, pumps, controls, be smaller than gross electrical generation. These are different bars, and the gap between them is large.

What Hyperion targets

Hyperion targets Q_sci of 3.076 with 85.0 MW of fusion power. At that operating point the 14 MeV neutron flux is sufficient to breed tritium and activate materials, which is the product. No conversion of fusion energy to net electricity is required for the foundry to function. The machine needs gain; it does not need net power.

Why the distinction matters for building first

Removing the net-electric requirement removes a chain of dependencies: high-efficiency conversion, minimized recirculating load, and the balance-of-plant scale that only pays off at large size. The breeder can therefore be compact and can be built and commissioned on a shorter path. The burner, by contrast, is designed toward net electric output through direct energy conversion, and its case closes only at fleet scale.

• Q_sci is a plasma-physics ratio; net electric is a whole-plant ratio
• Foundry products depend on neutron flux, which follows from gain
• No hardware net-gain claim is made before the first-of-a-kind unit

This is a design and simulation study. The gain-only framing is what makes a near-term first build credible, and it is stated honestly: gain is claimed as a design point, not as demonstrated hardware performance.