Various international decommissioning projects have shown that there are substantial variations in cost estimates for individual installations. Studies to understand the reasons for these differences have been somewhat hampered by the fact that different types of cost estimation methods are used, having different data requirements. Although some uncertainty is inevitable in any costing method, an understanding of the costing methods used in particular projects is useful to avoid key uncertainties. Difficulties of understanding can be encountered and invalid conclusions drawn in making cost comparisons without regard to the context in which the various cost estimates were made.
The above-mentioned difficulties are partly due to the lack of a standardised or generally agreed-upon costing method that includes well structured and defined cost items and an established estimation method. Such a structure and method would be useful not only for project cost comparisons, but would also be a tool for a more effective cost management.
The OECD/Nuclear Energy Agency (NEA), the International Atomic Energy Agency (IAEA), and the European Commission (EC) have ongoing activities addressing various aspects of decommissioning and decommissioning costs. Based on these concurrent activities and common objectives, and on the advantages of standardised cost item definitions, the three organisations agreed to jointly prepare and to publish a standardised list of cost items and related cost definitions, for decommissioning projects. The work was carried out by Belgoprocess (Belgium) in the framework of a shared-cost contract with the European Commission (Nuclear Fission Safety Programme 1994–1998). This paper presents the results of the co-operative work.