Net heatSteady stateFuel loopFirst powerSecond plant
More energy out of the plasma than we put into it. Every programme in the field is measured against this one number, including ours.
A shot that ends because we ended it, and not because a coil warmed through or a first wall ran out of margin.
The blanket has to breed tritium faster than the plasma burns it. Nothing about a plant closes until that ratio passes one.
The turbine house comes up and the first megawatt-hour leaves the site through a meter somebody else reads.
The same machine again, built from drawings rather than from physics, at half the cost and twice the pace.