Risks of radioactive material transportation accidents in Oregon

As a continuation of previous research on worst case transportation accidents involving radioactive material (Dodd and Humphries 1988a), and protective action guidance for radioactive material transportation accidents (Dodd and Humphries 1988b), this paper describes the risks from such accidents in Oregon. Radioactive material transportation risks are defined in terms of accident consequences multiplied by the accident probabilities and are expressed as latent cancer fatalities (LCFs). For each of 17 different shipment types, five dose contributions are summed and multiplied by the population density and accident probability. The five dose contributors considered are: inhalation, resuspension, cloudshine, groundshine and direct exposure. The variables over which each of these dose contributors are integrated include seven accident severity categories, three population density zones, five regions of the state, as well as many isopleth areas and radionuclides. Allowance is also made for the possible distribution of meteorological conditions in each area. The dose to the public, emergency responders, pedestrians and personnel in other traffic are all considered. It is concluded that the current level of risk is 1.2 X 10(-5) latent cancer fatalities per year in Oregon. This is equivalent to one LCF every 83,000 y. This compares to 1.2 non-radiological fatalities associated from the same shipments.