Hazards assessment of worst case transportation accidents involving typical radioactive material shipments

This paper reports the results of a study performed for the Oregon Department of Energy. The objectives of the study were to characterize the range of radioactive material shipments through the state and to determine the worst radiological hazards which might arise if these shipments were involved in transportation accidents. The direct and indirect radiological hazards were analyzed for worst case accidents involving a total of 10 typical shipments. The direct hazard primarily involved the gamma radiation from the material, while the indirect hazard considered the airborne release hazards of inhalation/ingestion, cloudshine and groundshine. The general and specific assumptions used in the study are given, and the results are tabulated, giving doses and dose rates as a function of distance. The data from the study are being incorporated into a protective action guide for use by state and local emergency responders. This guide bases the protective actions on the available, observable data and on flow charts which use the worst-case assumptions for unknown data.