The Kronos Layered Control Stack in Operation

The Kronos control stack layers fast stabilization, feedback regulation, supervision, and protection into one coordinated system.

The layers

Kronos organizes plasma control into distinct layers, each with its own timescale and authority. From fastest to slowest: a stabilization layer, a feedback-regulation layer, a supervisory layer, and an off-normal and protection layer that spans them all. Separating the layers keeps each simple and lets them be verified independently.

Stabilization layer

The fastest layer holds the plasma physically in place, above all vertical stabilization, which for a spherical tokamak like the Hyperion breeder is the tightest loop in the system. It runs on dedicated real-time hardware with the shortest latency budget so its deadline is never starved by slower tasks.

Regulation and supervision

The regulation layer tracks references for current, shape, density, stored energy, and the profiles, using feedback around the feedforward plan. The supervisory layer sequences discharge phases, arbitrates shared actuators, and switches controllers on and off as the scenario progresses. It is where the pulse schedule is executed.

Protection across the stack

The off-normal and protection layer watches every level. It detects developing faults, invokes recovery controllers, commands safe termination, and, as a last resort, hands off to the independent machine protection system. Its authority overrides performance, so it can halt any lower layer.

One stack, two machine types

The same layered pattern serves both product lines. The Hyperion breeder's stabilization layer centers on vertical control of its elongated, negative-triangularity plasma at 9.86 megaamperes. The burner generators, tandem-mirror devices, replace the tokamak-specific loops with plug-field and direct-conversion control while keeping the same layering and protection philosophy. Because both machines are in simulation ahead of construction in the second quarter of 2027, the whole stack is validated against models and rehearsed in the flight simulator before it commands hardware.