REAL DATA FOR REAL ROUTES

Over the last 25 years, methods used to estimate impacts of transporting radioactive materials have improved markedly. Early methods used expert judgment to estimate many of the parameters used in analyses. In addition, because the ability to collect and analyze large amounts of data was constrained by relatively unsophisticated computing technology, analysts in the 1970s and 1980s used characteristics of the transportation environment that have been described as “generic.” For example, analysts selected for their analyses route characteristics based on the average characteristics of all routes that might be used. In this regard, the earliest work used national average accident rates to estimate the frequency of transportation accidents that shipments might be involved in, national average travel speeds, and other data that were also averages over the length of a route. The Draft Environmental Impact Statement for a Nuclear Waste Repository at Yucca Mountain, Nye County, Nevada (DEIS) (DOE 1999) estimated impacts from transporting spent nuclear fuel (SNF) and high-level radioactive waste (HLW) from 77 U.S. locations to the Yucca Mountain repository in Nevada. The analysis, which included 10 transportation-implementing alternatives in Nevada (5 rail and 5 heavy-haul truck), used route-specific data to estimate transportation impacts. Examples of route-specific data used include: 1. Origin-specific, real highway and rail routes to Yucca Mountain 2. State-specific accident and fatality rate data. 3. State-specific food transfer factors to estimate ingestion doses. 4. State-specific population density data 5. Population data for the top 20 urbanized areas in the United States