COMPARISON OF MARKOV MODEL AND FAULT-TREE APPROACH IN DETERMINING INITIATING EVENT FREQUENCY FOR SYSTEMS WITH 2 TRAIN CONFIGURATIONS

This study explores the use of Markov models in some areas of systems analysis in which time evolution of the system may be a significant fa ctor in influencing the system reliability or availability. Comparison s are made between the Markov models and the time-averaged fault tree models for determining support system failure initiating event frequen cy in a nuclear power plant, for both power and shutdown conditions. F actors affecting consistency between the fault tree approach and the M arkov model approach are studied for systems with common two train con figurations. A correlation is developed to estimate the ratio between initiator frequencies through both approaches for a two parallel compo nent system. Insights are developed as to when time averaged and simpl ified fault tree models support a good approximation to the more rigor ous time-dependent Markov models. (C) 1996 Elsevier Science Limited