PASSIVE SYSTEM RELIABILITY MODELING OF THE COMBINATION OF FAILURE MODES

Innovative probabilistic models to extend the reliability analysis of passive systems under different modes of failure are proposed. The prevailing failure mode on the system can be predicted through the failure probability assessment on each specific mode. A realistic case is presented to analyze a passive system with two kinds of major failure modes natural circulation stoppage due to e.g., isolation valve closure (a catastrophic failure) and heat transfer process degradation due to e.g., deposit thickness on component surfaces (a degradation failure). Modeling of each individual failure mode together with system reliability analysis is presented and results are discussed.