LAUSR

Abstract In the last experimental campaign (OP1.2b: 7/2018 to 10/2018) of the Wendelstein 7-X stellarator (W7-X), the first of two neutral beam injectors (NBI) was commissioned with 2 plasma sources. The safe operation of the NBI requires the exclusion of hazards to personnel and minimization of system hazards. The NBIcontrol system consists of a standard PLC based on PCS7 from Siemens AG and a separate safety controller based on PNOZmulti from Pilz GmbH. The requirements of the NBI safety control are derived from an analysis of the specific personal and plant hazards in accordance with the international standards IEC 61508 / IEC61511. Particular challenges are the usage of high voltage, open high frequency and high power sub systems, and explosive gases that are distributed over different locations. Firstly, the paper describes the procedure followed by the hazard assessment and for determining solutions for safe operation. Secondly, the paper, describes the hardware structure of the NBI safety system. Lastly details of individual technical solutions, e.g. for access to the high voltage area of the NBI injector, are described.