KRONOS-CTRL: The Digital Twin Stack
KRONOS-CTRL is the coupled digital twin that holds a live physics state of each machine and projects it forward as a predictive shadow.
What KRONOS-CTRL is
KRONOS-CTRL is the digital-twin core of L3. It maintains a coherent state vector for the whole machine and advances it faster than real time, so that at any wall-clock instant the twin holds both the best current estimate of plant state and a 50-100 ms forecast of where the state is heading. Four physics modules run inside it and exchange boundary conditions every twin step.
- Power Systems: DEC electrode voltages, extraction efficiency, grid synchronization
- Neutronics: 14 MeV and residual D-D neutron flux, activation, breeding balance
- Thermomechanics: strain fields, thermal loads, divertor and first-wall margins
- MHD Stability: plasma shape, equilibrium, stability boundaries
How the modules couple
The modules are not independent. The MHD module fixes the equilibrium and hence the neutron source profile the Neutronics module integrates; Neutronics deposits volumetric heating that the Thermomechanics module turns into strain and temperature; Thermomechanics returns geometry changes (thermal expansion of the vessel, magnet strain via REBCO gauges) that shift the MHD boundary; and for the burner the Power Systems module closes the loop by setting the extraction potential that changes the ambipolar confinement the MHD module sees. KRONOS-CTRL solves this as a weakly coupled fixed-point iteration per twin step, using the previous step as a warm start so one or two Picard passes converge.
Each module is accelerated by an L3 surrogate (a PINN or neural operator) so the coupled step fits inside the shadow latency budget. The twin publishes, every step, a full state estimate, its forward projection, and a per-module confidence score that MPC and the anomaly ensemble consume.
KRONOS-CTRL is instantiated per machine. The breeder twin carries the Grad-Shafranov equilibrium, ELM dynamics and disruption observers; the burner twin carries the ambipolar-potential solve, plug-density balance and the multi-modal DEC train. Both share the same synchronization, surrogate and validation machinery.