Hydrogeologic performance assessment analysis of the commercial low-level radioactive waste disposal facility near West Valley, New York

A hydrogeologic performance assessment of the commercial low-level waste site near West Valley, New York, was performed for two pathways: a shallow lateral pathway where trench water can potentially migrate laterally through fractured and weathered till to nearby streams and a deep vertical pathway where leachate can migrate downward through unweathered till and laterally offsite in a lacustrine unit. Along the shallow pathway, little physical site evidence is available to indicate what the degree of lateral migration can be. Past modeling showed that overflowing trench water would migrate laterally some distance before migrating downward into the unweathered till. If water did reach a nearby stream, calculations show that decay, adsorption, and stream dilution would reduce leachate concentration to acceptable levels. Within the deep pathway, tritium and {sup 14}C were the only radionuclides released in any significant concentrations. Predicted tritium levels are well below regulatory limits; however, predicted peak {sup 14}C concentrations, while meeting the 25 mrem/yr limit using the drinking-water-only exposure scenario, exceed the limit for the full garden scenario. Site information on {sup 14}C release rates and geochemical behavior has considerable uncertainty and would need to be more fully evaluated in a licensing situation. 58 refs., 32 figs., 12more » tabs.« less