Development of an expert system for failure diagnosis of primary side systems

In this paper a prototype expert system, the NSSS-DS, is described. It is used for the diagnosis of three main systems-the rod control system, the reactor coolant pumps (RCPs), and the pressurizer-in the primary system of the Kori-2 nuclear power plant. This system diagnoses system malfunctions quickly and offers appropriate guidance to operators. The method of inference applied to this system is rule-based deduction with certainty factor operation. The diagnostic symptoms include alarms, indication lamps, parameter values, and valve lineup that can be acquired at the main control room. The application of this system to the rod control system, mainly consisting of electrical components, and the RCPs, mainly consisting of mechanical components, is described from the point of view of diagnostic strategies