Fusion Gain Q_sci 3.076

Q_sci is the ratio of fusion power to injected heating power; the Hyperion design point is 3.076, a scientific gain sufficient for a neutron foundry.

Defining the gain

Fusion gain Q_sci is defined as the fusion power produced divided by the external heating power delivered to the plasma. At the Hyperion design point this ratio is 3.076: 85.0 MW of fusion power for the heating that sustains the plasma. Q_sci above 1 means the plasma releases more fusion energy than the auxiliary systems put into it, but it says nothing yet about electricity delivered to a grid.

What Q_sci 3.076 buys

At Q above roughly 3 a significant fraction of the plasma heating comes from the fusion alpha particles themselves rather than from external injection. The plasma is partly self-heated. For a foundry this is enough: the 85.0 MW of fusion power corresponds to a neutron production rate that drives breeding and activation at the throughput the design targets. The neutrons are the product; the gain is the means.

What it does not claim

• Not engineering gain (Q_eng), which accounts for all plant recirculating power
• Not ignition, where alpha heating alone sustains the burn
• Not a measured result — 3.076 is a design-and-simulation value

Keeping these distinctions explicit is deliberate. A single unqualified Q number is the most common way fusion claims mislead. Hyperion states scientific gain and stops there.

This page describes a design-and-simulation study, not a built machine. Construction begins Q2 2027; first-of-a-kind first tritium is targeted near 2030. No hardware net-gain is claimed before FOAK.