Deep Dive: The Field-Lever Upgrade Path
A design-space study (S78) shows a constraint-checked upgrade — nudging B₀ and R_c — that either holds the field at the demonstrated 24.4 T or buys +6% fusion power. The frozen design is unchanged.
- What
- A B₀/R_c toroidal-field lever (S78)
- Option A
- Hold peak at demonstrated 24.4 T, better margins
- Option B
- Spend headroom for +6% Pfus (2409→2557 MW)
- Status
- Available upgrade — frozen design NOT changed
Beyond the frozen design point, Kronos deposits forward-looking design-space studies that ask "can it be better?" — and publishes the answers honestly, favourable or not. The field-lever study (S78) is a favourable one.
It examines a small, fully constraint-checked move: shifting the peak-field radius R_c from 1.40 to 1.44 m and the on-axis field B₀ from 6.0 to 6.11 T. Evaluated through the coupled systems code (so every number survives the simultaneous constraint check), this lever offers a choice — either hold the peak conductor field at the demonstrated 24.4 T (down from 24.6 T) while improving Troyon and kink margins, or spend the freed β_N headroom for +6% fusion power (2409 → 2557 MW) at unchanged confinement.
Crucially, this is an available upgrade path, not a change to the committed design — the frozen MetroVolt point stands, and adopting the lever would gate on an inboard-neutronics re-run. It's an example of Kronos mapping its headroom transparently rather than quietly baking in optimistic numbers.