Diagnostic strategies of a prototype expert system for malfunction diagnosis of primary-side systems in nuclear power plant

Abstract

A prototype expert system, called NSSS-DS, has been developed 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 in Korea. This system diagnoses system-malfunction quickly and offers appropriate guidance to operators. This system uses rule-based deduction with certainty factor operation. The diagnostic symptoms include alarms, inducation lamps, parameter values and valve line-up that can be received at the main control room. The overall plant-wide diagnosis is performed by the main control part which processes the fired multi-alarm information and diagnoses possible transients and failed systems. The specific diagnosis of the three main systems is performed followed by the diagnostic results of the main control part. The application to these systems is described from the point of view of diagnostic strategies.