DEEP GEOLOGIC DISPOSAL OF RADIOACTIVE WASTE: MULTIPLE OPTIONS FOR LONG-TERM ISOLATION (Invited Presentation)

Worldwide, every nation that has a significant inventory of spent nuclear fuel and high-level radioactive waste has come to the conclusion that deep geologic disposal is the scientifically preferred option for isolating wastes from the human environment. Many nations are in various stages of planning or developing mined repositories for radioactive waste disposal, relying on a range of disposal concepts that take advantage of the potentially available rock types. For example, Finland is moving forward with plans for a repository in Precambrian gneiss, Sweden is seeking authorization for a repository in granite, France is conducting research in argillite, Canada is considering both granitic and sedimentary rocks, Germany has extensively investigated disposal options in salt, and the US has disposed of intermediate-level transuranic waste in salt at the Waste Isolation Pilot Plant in New Mexico. Since work on the formerly proposed Yucca Mountain repository in Nevada was terminated in 2010, the US Department of Energy has conducted research and development on generic disposal concepts in multiple lithologies, including salt, crystalline rock, and argillaceous rock. Detailed assessments of the long-term performance of different disposal concepts indicate the primary factors contributing to robust isolation vary depending on details of the geologic setting and the design of the engineered system, including waste packaging, chosen for the site-specific subsurface environment. Overall, decades of research and development in the US and other nations support a conclusion that robust isolation is achievable in many lithologies by relying on various combinations of natural and engineered barriers.

Sandia National Laboratories is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000. This abstract is Sandia publication SAND2016-6666 A.