The Science and Technology Program (S&T) within the DOE Office of Civilian Radioactive Waste Management (OCRWM) was conducted over the period 2003 through 2007. This program was distinct from, but parallel to, the licensing effort at Yucca Mountain. The role of S&T was to advance technologies not previously considered, to identify new or substantially revised scientific methods or tools, thus providing a better understanding of the repository environment. The S&T program goals were to reduce cost, reduce uncertainty, enhance performance, develop new technologies, and overall greatly enhance the repository system, its performance, and its defensibility during and beyond the License Application defense. The science component of the S&T program was organized into three targeted thrust areas.
Berkeley Lab’s Earth and Environmental Sciences Area was the Lead for the Natural Barriers Thrust. The goal of the Natural Barriers Thrust was to provide the essential scientific basis of how and to what extent the unsaturated and saturated volcanic rocks at Yucca Mountain contribute to repository performance. The enhanced understanding of the different processes in the natural system provided greater confidence in Yucca Mountain modeling. The Natural Barriers Thrust funded competitive proposals from universities and national laboratories. Berkeley Lab scientists conducted research pertaining to:
- In-drift processes, integrating thermal-hydrologic-chemical-transport (THCM) models that simultaneously consider source term, corrosion, and the hydrological-chemical environment around waste package processes and conditions—and synthesizing these complex processes into transparent, realistic, and defensible process model.
- Near-drift processes, such as found in laboratory, field, and analogue studies, to confirm the drift shadow concept and its ability to delay and sorb radionuclides in the near-drift region.
- Processes and conditions that will retard or mitigate flow and transport through unsaturated and saturated volcanic rock.
The goal of the Source Term Thrust was to enhance the understanding of the performance of nuclear waste forms (mainly spent nuclear fuel (SNF) and nuclear waste glass) and to quantify the release of radionuclides in the evolving near-field environment expected at the proposed nuclear waste repository at Yucca Mountain, Nevada. The behavior of the source term, mainly SNF and vitrified waste, limits radionuclide releases, both initially and over the long term. Interactions of the source term with the near-field environment, such as corroded waste packages, place additional constraints on the long-term behavior, including retention and mobility of important radionuclides.
The materials used for isolating waste in the proposed repository are an important component of the overall approach to the design of the repository system. Opportunities exist to enhance the understanding of material performance and to probe technical enhancements. These enhancements may include optimizing the performance of waste packages and drip shields for increased reliability and cost effectiveness. The goal of the Materials Performance Thrust program was to further enhance the understanding of the role of engineered barriers in waste isolation. In addition, the thrust will explore technical enhancements and seek to offer improvements in materials cost and reliability.
- Office of Science and Technology and International (OST&I) Annual Report 2005, U.S. Department of Energy, Office of Civilian Radioactive Waste Management (DOE/RW-0581, 220 pp.).
- Office of the Chief Scientist Science, Technology, and Management Research Summaries Fiscal Years 2006-2007 U.S. Department of Energy, Office of Civilian Radioactive Waste Management (DOE/RW-0594, 179 pp.)