The KRONOS-CTRL Digital Twin
A modular predictive twin — Power, Neutronics, Thermomechanics, MHD — running a 50-100 ms shadow of the machine for state estimation and control.
A machine that runs ahead of the machine
KRONOS-CTRL is the digital twin at the heart of L3. It maintains a live, physics-based state estimate of the reactor and projects it forward, running a predictive shadow 50-100 ms ahead of the present. Control reasons over that shadow, so the plant acts on where the machine is going, not only where it is.
The four modules
- Power — plasma power balance and heating response.
- Neutronics — 14 MeV neutron transport and, on the breeder, tritium breeding across the TBR lever.
- Thermomechanics — vessel, divertor, and cocoon thermal and structural state.
- MHD — equilibrium and stability, the dominant control physics on both machines.
How it stays faithful
The twin is continuously reconciled with L2 telemetry. GNNs fuse the diagnostics constellation and impute dropped channels; PINNs enforce the governing equations so the state estimate honors physics rather than merely fitting data. The gap between prediction and observation is itself a monitored signal, feeding anomaly detection and the retraining loop.
Both machines
On the breeder the twin tracks the negative-triangularity equilibrium and disruption margin; on the burner it tracks end-plug density, the ambipolar potential, and the charged-particle flux into the DEC train. The module structure is shared; the physics inside MHD and Neutronics differs per machine, which is exactly the one-architecture-two-machines pattern in action.
The twin's source truth is the source-of-truth principle from the design philosophy, and its inputs come from the diagnostics constellation.