Risk Comparison of Methods for Dependency Determination within Human Reliability Analysis

摘要

Dependency between human failure events is an issue, which include subjectivity in the models and consequently in the results of human reliability analysis and thus in probabilistic safety assessment. Many methods connected with human reliability analysis were developed in the last decades, which mostly include determination of dependency between human failure events: e.g. Standardized Plant Analysis Risk HRA - SPAR-H and Institute Jo?ef Stefan - Human Reliability Analysis - IJS-HRA. A comparison of dependency as it is applied within the selected methods is performed on an example probabilistic safety assessment model of a selected nuclear power plant. Pre-initiators and post-initiators are considered. It is investigated how the contribution of consideration of dependency of pre-initiators and dependency of post-initiators and dependency of both impacts the human error probabilities, which are then used within probabilistic safety assessment. The results of comparison show that selection of the method for determining dependency between human failure events may largely impact the results of human reliability analysis and consequently the probabilistic safety assessment. The subjectivity can be reduced by development of more detailed guidelines for human reliability analysis with many detailed practical examples for all steps of the process of evaluation of human performance.