Expected waste package performance for nuclear waste repositories in three salt formations

Expected waste package lifetimes and radioactive releases from the package were predicted at seven sites in three geologic formations for both commercial high-level waste (CHLW) and spent nuclear fuel from pressurized-water reactors (SFPWR) using near-field conditions from preliminary analyses. The predicted expected lifetimes for both CHLW and SFPWR waste packages exceeded 10,000 years at all seven repository sites. These conclusions are based on expected uniform corrosion of packages with thick containers of low-carbon steel and uniform distribution of the limited quantity of local brine that migrates thermally toward the waste package and becomes available to react with the steel in the waste container. The maximum quantities of radionuclides that would be discharged at failed packages would be limited to a small fraction of the EPA standard at the site boundary except for isotopes of highly soluble iodine, cesium, and perhaps sparingly soluble strontium. The conclusion of this assessment of waste package performance under expected conditions is that all seven sites are within regulatory requirements. However, the domes, in spite of their higher temperatures, have a greater tolerance for error both in the analytical model and in the input data estimates than the bedded sites because of their expected lower water contents and because of their less corrosive low-magnesium in situ brines. 37 refs., 49 figs., 19 tabs