[en] This paper describes some of the results of a Nuclear Energy Agency (of the Organisation for Economic Cooperation and Development) report to be published in 2015: Costs of Decommissioning Nuclear Power Plants. Because of the confidential nature of the data obtained by questionnaires from representatives of NEA member countries, this paper discusses the translation of publicly available decommissioning costs and estimates with an emphasis on completed decommissioning costs in the U.S. for Haddam Neck, Maine Yankee, Trojan, and Rancho Seco. This translation is from the codes of accounts used by TLG Services into the IAEA/EC/NEA International Structure for Decommissioning Costing, ISDC (2012). We show how to dis-aggregate the TLG Work Breakdown Structure, WBS, into Level 3 ISDC codes and re-aggregate to categories that allow cross-country comparisons. We find that while the cost of decontaminating and dismantling a nuclear power unit has changed little over time, uncertainties remain in estimating waste disposal costs, on-site spent fuel storage, and site release criteria. The approximate total decommissioning cost including dismantling, waste management and project management, appears to be 500 millions dollar per nuclear power unit