ABSTRACT
Collecting and assessment of operational experience has numerous attractions and benefits in all major industrial activities. Understanding of the most important difficulties with limited access to the industry wide operational experience and its proper application are still subject of ongoing research. One special problem is to identify the most important groups of events from the collected experience because it is not feasible to investigate in sufficient details all of them. This paper is analyzing how events groups’ prioritization is sensitive to the selected ranking method and to the events grouping. The base for the analysis was set of twenty years of experience from nuclear power plants in two countries. The method difference is mainly related to the type of ranking indexes used (regarding equations and logic) and weighting factors applied (i.e., is importance of ranking indexes equal or not). The finding is that sensitivity is large because different ranking approaches and groupings produce important changes in rankings. The fact is that different ranking approaches have fairly good agreement related to the top listed groups of events. However, the precise events groups order differs significantly between methods and different groupings. Further assessment of ranking methods seems important in order to make better judgment about most preferred ranking method and groupings. This is important in order to increase credibility of ranking results and relax ranking process.
