Probabilistic accident consequence uncertainty assessment using COSYMA : uncertainty from the early and late health effects module

A study to perform an uncertainty analysis of the European accident consequence assessment system, Cosyma, has been carried out under contract to the European Commission. The study involved a series of analyses of the uncertainty in different sections of the system, followed by a final analysis of the uncertainty in the whole system. The overall aims of the study can be summarised as: to formulate a state-of-the-art expert judgement methodology which is capable of finding broad acceptance; to apply the methodology to estimate uncertainties associated with the predictions of the probabilistic accident consequence assessment system, Cosyma; to provide an input to identifying future research and development priorities. This report describes the analysis of the uncertainty in he health module of Cosyma. Specifically, it describes the analysis of the uncertainty in the model predictions resulting from uncertainty in the values to be assigned to the input parameters describing the risk of health effects from known doses of radiation. The main aim of this part of the study was to identify the input parameters whose uncertainties make large contributions to the overall uncertainty; the parameters identified would then be included in the final analysis of the uncertainty in the whole system.