On when to base event trees and fault trees on probability models and frequentist probabilities in quantitative risk assessments

摘要

This paper discusses the analysis approach when using event trees and faulttrees in a quantitative risk assessment context. The basic question raised is when tointroduce probability models and frequentist probabilities (chances) instead of usingdirect probability assignments for the events of the trees. We argue that such modelsshould only be used if the key quantities of interest of the risk assessment are frequentistprobabilities and when systematic information updating is important for meeting the aimof the analysis. An example of an event tree related to the analysis of an LNG (LiquefiedNatural Gas) plant illustrates the analysis and discussion.