Designing a Bayesian Network for Preventive Maintenance from Expert Opinions in a Rapid and Reliable Way

TL;DR

This paper introduces a method to efficiently design Bayesian Networks for nuclear plant maintenance by simplifying probability assessments through expert knowledge, ensuring consistency and reliability in the model.

Contribution

It presents a novel approach using log-linear models and simplification rules to reduce complexity and improve the reliability of expert-derived probabilities in Bayesian Networks.

Findings

Significant reduction in probabilities needed from experts.

Rules for selecting the most reliable probabilities.

Method successfully applied to nuclear plant component.

Abstract

In this study, a Bayesian Network (BN) is considered to represent a nuclear plant mechanical system degradation. It describes a causal representation of the phenomena involved in the degradation process. Inference from such a BN needs to specify a great number of marginal and conditional probabilities. As, in the present context, information is based essentially on expert knowledge, this task becomes very complex and rapidly impossible. We present a solution which consists of considering the BN as a log-linear model on which simplification constraints are assumed. This approach results in a considerable decrease in the number of probabilities to be given by experts. In addition, we give some simple rules to choose the most reliable probabilities. We show that making use of those rules allows to check the consistency of the derived probabilities. Moreover, we propose a feedback procedure to eliminate inconsistent probabilities. Finally, the derived probabilities that we propose to solve the equations involved in a realistic Bayesian network are expected to be reliable. The resulting methodology to design a significant and powerful BN is applied to a reactor coolant sub-component in EDF Nuclear plants in an illustrative purpose.