The Risks and Consequences from the Transport of Low Specific Activity Materials by Truck

The packaging and transport category of low specific activity (LSA) material was conceived for radioactive materials (RAM) that were considered inherently safe for transport. Such materials could be transported in \"strong, tight\" packages. The primary concern for the radionuclide content in LSA matenals was associated with the potential for inhalation of particulate radioactive material. Thus, the specifications for the category in terms of specific activity were structured to preclude excessive inhalation hazard. The current version of the International Atomic Energy Agency (IAEA) regulations maintains the inhalation-related limits but also shows concern that the restrictions on the LSA category may not preclude an excessive external radiation hazard for gamma-emitting materials. ThiS {>aper presents the results of an investigation of the potential for such excessive external radiation hazards, particularly for LSA materials with specific activity levels near the current regulatory limit (Ostmeyer et al 1988). This paper discusses analyses that were performed to evaluate the potential radiologtcal impacts of highway accidents leading to the release of high radiation level-low specific activity (HRL-LSA) materials from their packagings. The results of the analyses are intended to provide a basis for evaluating restrictions on the quantity of gamma-emitting radionuclides that can be contained in an LSA shipment. Consequences of a very severe accident were estimated to gauge the relative impact of three potenttal LSA specifications: 1. The current regulatory restriction on specific activity (0.3 millicuries per gram per radionuclide ). 2. The specific activity consistent with a package dose-rate restriction of 1 rem/hr at 3 m from the package. 3. The specific activity consistent with a package dose-rate restriction of 1 rem/hr at 1 m from the package. A risk analysis, using a spectrum of LSA shipments consistent with current shipping levels, was performed to demonstrate the level of risk of HRL-LSA shipments compared with all other LSA shipments and to compare with other analyses involvmg estimation of risk.