Calculation of population doses with RADTRAN for route segments that have an unpopulated near-field region

The RADTRAN code (Neuhauser and Kanipe, 1994) models the radiological consequences of the transportation of radioactive materials, both the exposures that will occur if the transport occurs without incident, and the exposures that may occur should the transport vehicle be involved in an accident while en route. Because accidents might occur at any point along a transportation route, RADTRAN divides the route into segments (links) and uses a uniform population density and constant meteorological conditions (wind speed and atmospheric stability) to represent the population and weather characteristics of each route segment. A way to perform RADTRAN calculations, that allows an unpopulated near-field region along a transportation link to be approximately modeled, is described, validated, and then illustratively applied to a coastal sailing route