UNCERTAINTY IN TRANSPORTATION RISK ASSESSMENT

Transportation risk assessment involves a number of parameters whose values are uncertain. RADTRAN© (hereinafter referred to simply as RADTRAN) is now capable of handling uncertain input parameters. Incorporating uncertainty into various parameters can provide valuable insights into the role of these parameters in estimating risks of transporting radioactive materials. The present paper presents the results of using different distributions for the following RADTRAN inputs: external gamma radiation dose rates from a transportation cask, size of exposed populations, accident rates, particle deposition velocities, fractions of material released from a cask under various accident conditions, fractions of released material that is aerosolized, radionuclide inventory of spent nuclear fuel (since burnup and age may be uncertain), wind speed, and Pasquill stability class. The last two parameters are coupled; this paper also discusses approaches to the incorporation of uncertainty into coupled input parameters.