Management of the Wendelstein 7-X Central Safety System Using a Requirement Engineering Tool

A safety instrumented system (SIS) is in place for the continuous safe operation of Wendelstein 7-X (W7-X). The central safety system (cSS) is part of this system. Prior to the last operation phase (OP) 2.1 in preparation for the steady-state regime, the cSS was fundamentally revised. A requirements engineering tool (RET) was introduced to support the development process. The SIS development plan, adapted to the W7-X, provides for fixed steps. All functional requirements derived from the W7-X risk analysis for the cSS and derived objects along the safety lifecycle are documented in the RET by means of work items. In this way, the requirements of the SIS standards and those of the approving authorities can be met. Dependency relationships have been established between the work items to allow the analysis of completeness, dependency, and explicitness, as well as the analysis of the impact of possible changes at any point in the process. The requests for adaptations and extensions to the cSS, derived from the experience with the SIS in OP2.1, are also organized with the RET.