HR: 1340h
AN: H13A-1328    [Abstracts]
TI: Use of Groundwater Lifetime Expectancy for the Performance Assessment of Deep Geologic Radioactive Waste Repositories.
AU: * Cornaton, F
EM: fcornato@scimail.uwaterloo.ca
AF: Department of Earth Sciences University of Waterloo, 200 University Ave West, Waterloo, ON N2L 3G1 Canada
AU: Park, Y
EM: yjpark@uwaterloo.ca
AF: Department of Earth Sciences University of Waterloo, 200 University Ave West, Waterloo, ON N2L 3G1 Canada
AU: Normani, S
EM: sdnorman@civmail.uwaterloo.ca
AF: Department of Civil Engineering University of Waterloo, 200 University Ave West, Waterloo, ON N2L 3G1 Canada
AU: Sudicky, E
EM: sudicky@sciborg.uwaterloo.ca
AF: Department of Earth Sciences University of Waterloo, 200 University Ave West, Waterloo, ON N2L 3G1 Canada
AU: Sykes, J
EM: sykesj@uwaterloo.ca
AF: Department of Civil Engineering University of Waterloo, 200 University Ave West, Waterloo, ON N2L 3G1 Canada
AB: Long-term solutions for the disposal of toxic wastes usually involve isolation of the wastes in a deep subsurface geologic environment. In the case of spent nuclear fuel, the safety of the host repository depends on two main barriers: the engineered barrier and the natural geological barrier. If radionuclide leakage occurs from the engineered barrier, the geological medium represents the ultimate barrier that is relied upon to ensure safety. Consequently, an evaluation of radionuclide travel times from the repository to the biosphere is critically important in a performance assessment analysis. In this study, we develop a travel time framework based on the concept of groundwater lifetime expectancy as a safety indicator. Lifetime expectancy characterizes the time radionuclides will spend in the subsurface after their release from the repository and prior to discharging into the biosphere. The probability density function of lifetime expectancy is computed throughout the host rock by solving the backward-in-time solute transport equation subject to a properly posed set of boundary conditions. It can then be used to define optimal repository locations. In a second step, the risk associated with selected sites can be evaluated by simulating an appropriate contaminant release history. The proposed methodology is applied in the context of a typical Canadian Shield environment. Based on a statistically-generated three-dimension network of fracture zones embedded in the granitic host rock, the sensitivity and the uncertainty of lifetime expectancy to the hydraulic and dispersive properties of the fracture network, including the impact of conditioning via their surface expressions, is computed in order to demonstrate the utility of the methodology.
DE: 1803 Anthropogenic effects (4802, 4902)
DE: 1831 Groundwater quality
DE: 1832 Groundwater transport
DE: 1849 Numerical approximations and analysis
DE: 1874 Ungaged basins
SC: Hydrology [H]
MN: Fall Meeting 2005