Salt Reconsolidation and Repository Engineered Barriers - 18651
Salt repositories for the permanent disposal of hazardous waste provide extraordinary advantage over other geo-media because geotechnical barriers can be constructed with confidence using crushed salt, which is a perfectly compatible material that is readily available by mining practice. Other excellent barrier materials that consist of specialty mixes of salt-based concrete, bentonite, and bitumen bolster confidence that a repository in geologic salt formations will remain impermeable forever. Practically speaking, achieving high-performance engineered barriers assumes an isolation role as important as the host formation itself. Long-term performance assessment intrinsically includes evaluating seal-system design and demonstrated operational characteristics. Consistent with global interests, specific research on salt-repository seal systems not only established significant technical bases but identified possible improvements through straightforward research and laboratory and field investigations. Engineered barriers of crushed salt with possible additives, such as clay and water, evolve to create hydrological and mechanical characteristics that approach those of the host salt formation. Demonstrating early functionality of seal systems reduces uncertainty, which is introduced when calculating or predicting when performance properties become effective in the future. (authors)