Improving Human Reliability Assessment Using Bayesian Belief Networks (bbn): A Case Study On Maintenance In Pht And Steam Generator

Presentation Title: Improving Human Reliability Assessment using Bayesian Belief Networks (BBN): a case study on maintenance in PHT and Steam generator Research focus: Human Reliability Assessment (HRA) for Nuclear Power PlantsLevel: Bachelors Abstract: Analysis of human error is very case-specific; the context of the field should be considered while analyzing. The aim of this study is to identify the causes of human errors and improve human reliability in the nuclear industry. The thrust of this study is to employ the most futuristic approach to Human Reliability Assessment (HRA) techniques – Bayesian Belief Network (BBN) - for estimating human error probabilities and then to check the consistency of the results obtained. In HRA, BBN applications are steadily increasing, each emphasizing a different BBN feature or a different HRA aspect to improve e.g., ability to deal with data scarcity, to incorporate information from diverse sources, to model complex multi-layer relationships. The present paper systematically reviews these applications, critically reviewing these features as well as identifying prospective research opportunities.This study reviews present HRA methods (SPAR-H and CREAM) and proposed two aspects to improve them using BBN. Firstly, expansion of the Performance Shaping Factors (PSFs) nodes into additional parent nodes further specifying influencing factors. Second, capturing of PSF interdependency. The BBN can easily capture this interdependency by connecting the nodes. The present paper also analyses the approaches used to obtain the expert knowledge, to include it into the BBN model and to combine this expert data with empirical data, when available. Microsoft Bayesian Network Editor (MSBNx), a non-commercial software, is used to calculate the probabilities conveniently. The case study taken is on ‘the maintenance works on one of the PHT pumps’ in a nuclear reactor. The probabilities and the conditional probabilities associated with each intermediate child node were acquired based on the assumption with help of the data given from the “A Guide to Practical Human Reliability Assessment by Barry Kirwan 1994”.