A Screening Model for Calculating the Risks of Transporting High Level Radioactive Waste

Abstract

In transporting high level radioactive waste (including spent nuclear fuel), shippers (and sometimes carriers) need to evaluate the risks of potential radiation exposure to the public and transport workers. A simple model is presented that can be applied to nuclear waste transport risk assessments. The model considers radiation risks arising from incident free exposure, accidental release-caused exposure to on-link population, off-link population, crew, transport workers, etc. Important parameters and factors that affect the radiation dose level are grouped using the physics of the different exposure phenomena. The total radiation risk (in person-rems) is given by a linear combination of the groups of these factors, each representing a different type of exposure. The radiation exposure risk assessment is reduced to the evaluation of a single linear algebraic equation containing five distinct terms and each term containing the groups of parameters and a constant coefficient. The estimation of the values of the constant coefficients was accomplished by selecting a sample of 65 origin-destination (0-D) pairs and simulating the shipment of high level nuclear waste or spent nuclear fuel between each O-D pair, and evaluating the radiation dose risks to each group of population. RADTRAN 4 was used in the detailed assessments. The coefficient values were tested for statistical robustness using a sampling hypothesis and t-statistics. These values are presented. The simplified model presented here represents a viable and economical option as a radiological risk assessment tool, to be used in mode or route options screening.