Implementation of a Testing and Diagnostic Concept for an NPP Reactor Protection System

This paper presents the concept and practical realization of the testing and diagnostic methodology for a reactor protection system in a nuclear power plant. The test concept utilizes the highly redundant nature of these systems to conduct tests during the normal operation of the monitored process. The diagnostic concept uses a simple rule-based expert system to locate the root cause of the failure indications. The diagnostic system can be integrated into a risk monitoring solution, which monitors and computes the functional degradation of the most important safety activities of the protection logic. The described principles have been implemented in the form of microcomputer-based testing and diagnostic systems.