ABSTRACT
A. Rauzy Institut de Mathématiques de Luminy, Marseille, France
E. Meléndez Consejo de Seguridad Nuclear (CSN), Madrid, Spain
F. Nieto Instituto de Investigación Tecnológica (IIT), Universidad Pontificia Comillas. Madrid, Spain
ABSTRACT: Binary Decision Diagrams (BDD) are a well-known alternative to the minimal cutsets approach to assess Fault Trees and Event Trees involved in the Probabilistic Safety Assessment studies of the nuclear industry. However, for many real PSA models the full conversion procedure remains out of reach in terms of computational resources. A potential solution to improve the quality of assessment methods is to design hybrid algorithms that combine the calculation of MCS with the BDD methodology. As a first step to develop this approach, in this article we explore the idea of reducing the fault tree model by considering only the domain of the most relevant MCS prior to the BDD conversion. The long term objective is to apply this reduction procedure to quantify sequences of linked Fault Trees, both static and dynamic. We propose as well several ordering heuristics derived from the MCS and the structural information of the model, and we compare both its general performance and its sensitivity to the initial rewriting of the model.
