Steady-State Fuel Demand

Once running and recycling, a burner's net helium-3 draw is small; steady-state demand is set by the unrecovered fraction, not the full throughput.

Running demand versus throughput

A common error is to equate a burner's helium-3 demand with the amount of fuel cycling through its plasma. Throughput is large — fuel is injected, mostly not burned per pass, and recovered. But net demand is only the part not returned to store: unburned fuel lost to imperfect recovery, plus the helium-3 actually consumed by fusion. With effective recycling, steady-state net demand is a small fraction of throughput.

What sets it

Steady-state demand rises with the fusion power sustained (more burn consumes more fuel) and falls with better recovery efficiency (less unburned fuel lost). It does not depend on throughput directly. This is why recycling is treated as essential rather than optional: it is the lever that keeps net demand low enough for a breeder fleet to sustain many burners at once, rather than only a few.

• Net demand = fuel burned + unrecovered unburned fuel
• Independent of the much larger throughput
• Rises with sustained power, falls with recovery efficiency
• Low steady-state demand is what makes fleets feasible

Steady-state demand per burner, added to periodic startup charges, is what the fuel-accountancy and inventory systems track against the breeder's ~1.97 kg/yr-class output to plan the fleet.