Evaluation of potential hydrologic tracers in tuffs from Yucca Mountain, Nevada

Laboratory column studies were performed on five lithologically different crushed volcanic tuff samples from the proposed high-level nuclear waste repository site at Yucca Mountain, Nevada, to evaluate bromide, iodide, and borate as potential groundwater tracers at Yucca Mountain. The studies consisted of an experimental portion and a modeling portion. In the experimental portion, solutions containing tritium, bromide, iodide, and borate were leached through the packed columns under both saturated and unsaturated flow conditions. In addition, four fluorobenzoate tracers and 18O enriched water were added during one of the unsaturated flow experiments as additional tracers. Effluent fractions were collected and analyzed for tracer concentrations and other hydrochemical characteristics. In the modeling portion, the experimental results for tritium were simulated using a flow and transport model, which is operable on USGS computers. 1 ref