Methods for CEC/USNRC accident consequence uncertainty analysis of dispersion and deposition The European Commission, DG XII, has published a report entitled "Methods for CEC/USNRC accident consequence uncertainty analysis of dispersion and deposition". The report is the product of joint study by the European Commission and the United States Nuclear Regulatory Commis... The European Commission, DG XII, has published a report entitled "Methods for CEC/USNRC accident consequence uncertainty analysis of dispersion and deposition". The report is the product of joint study by the European Commission and the United States Nuclear Regulatory Commission (USNRC) into the uncertainties associated with the predictions of the COSYMA and MACCS computer codes for assessing the radiological consequences of postulated accidental releases from nuclear installations. Previous estimates of the uncertainties associated with the predictions of these codes have certain limitations. In order to overcome these limitations, the EC and USNRC developed the study with the following objectives in mind: - To formulate a generic, state of the art methodology for uncertainty estimations which is capable of finding broad acceptance; - To apply the methodology to better quantify and obtain more valid estimates for the uncertainties associated with the predictions of COSYMA and MACCS. The first phase of this joint study was concerned with uncertainties resulting from the prediction of the dispersion of radioactive material in the atmosphere and its ground deposition. This report is being published as a complement to the previously published main report. It contains a fuller treatment of the techniques for uncertainty analyses developed by the EC contractors and of the difference in the results obtained when using equal or performance-based weighting of judgements of uncertainties.
