Runtime resource checking at WENDELSTEIN 7-X during plasma operation

The super conducting stellarator WENDELSTEIN 7-X (W7-X) is designed as a steady-state device which will run pulses of 30 min or more. During discharges W7-X will be controlled by a dedicated “segment control system” addressed in this article. the innovative nature of a fusion device and its subsystems a failure of a subsystem during a discharge cannot be ruled out. Safety critical failures are handled by the safety system. In many cases a failure leads only to a degradation of the plasma quality and not to a safety critical situation. Because of the long pulses the segment control has to detect the situation and steer the discharge into another state in which preferably the discharge can continue without the failed subsystem or the discharge is gracefully brought to an end. a short summary of the main aspects of the “segment control system” this paper deals with the online resource check required for fault detection and recovery. It explains how the online resource check is integrated in the control system and how the control system support recovery strategies.