Reliability Analysis of Digital Instrumentation and Control Systems

Abstract

The NUREG-CR/6942 technical report proposed a Markov state transition model for the main feedwater valve (MFV) controller system as part of a Probabilistic Risk Assessment (PRA) of Digital Feedwater Control System (DFWCS). The proposed model extends the Markov model to allow the use of non-exponential distribution in the time to next output of the controller system responsible for maintaining the water level. This case study demonstrates the general application of semi-Markov process model for digital instrumentation and control systems. System failure probability and mission reliability measures are determined.