Control-System and Interlock Safety

Safety interlocks are deterministic and fail-safe: on any fault or loss of signal, the machine drives itself to a safe state.

Operating a fusion plasma requires sophisticated control, but the safety functions are kept simple, deterministic, and independent of the complex control that maximizes performance. Safety interlocks act on clear conditions with fail-safe logic: ambiguity, fault, or loss of signal all resolve toward the safe state, which for fusion means ending the burn.

Interlock principles

• Fail-safe: loss of power or signal drives to the safe state (de-energize, terminate).
• Deterministic: safety logic is simple and predictable, not dependent on complex inference.
• Independent: safety interlocks are separate from the performance-control system.
• Access protection: the machine cannot operate with radiation barriers open.

The safe state is easy to reach because the reaction wants to stop: cutting heating or fueling, or opening the field, ends the burn in seconds. This is the advantage of a system whose failure direction is off — the interlocks push in the direction the physics already goes. Access interlocks physically prevent operation when personnel could be exposed to the neutron field.

Relation to AI control

The performance-control system may use advanced methods to keep the plasma burning, but it is layered beneath the deterministic safety interlocks, not trusted to provide safety itself. See AI control and safety interlocks. This separation keeps the safety case simple and independent of the complexity of optimal control.

Safety comes from simple, fail-safe logic acting on a reaction that already tends toward off.