HR: 0800h
AN: H31D-0410    [Abstracts]
TI: Effects of Natural Drift Degradation on In-Drift Thermohydrological Conditions
AU: * Manepally, C
EM: cmanepally@cnwra.swri.org
AF: Center for Nuclear Waste Regulatory Analyses - Southwest Research Institute, 6220 Culebra Road , San Antonio, TX 78238 United States
AU: Sun, A Y
EM: asun@cnwra.swri.org
AF: Center for Nuclear Waste Regulatory Analyses - Southwest Research Institute, 6220 Culebra Road , San Antonio, TX 78238 United States
AU: Fedors, R W
EM: rfedors@cnwra.swri.org
AF: Center for Nuclear Waste Regulatory Analyses - Southwest Research Institute, 6220 Culebra Road , San Antonio, TX 78238 United States
AB: Understanding thermohydrological processes at the potential high-level waste repository at Yucca Mountain, Nevada, is important for assessing its long-term performance. Detailed process models that provide the in-drift and near-field thermohydrological conditions are needed to estimate the composition of water that may contact the waste package and to evaluate the potential for corrosion of waste packages. Drift degradation could significantly influence the environment inside waste emplacement drifts. Degradation of the host rock may backfill portions of the repository, and drifts could potentially be backfilled within 1000 years after closure. This poster presents a two-dimensional detailed process model that incorporates the temporal variation of in-drift and drift wall geometry as a result of drift degradation. Model results indicate that radiation and convection dominate in-drift heat transfer until the drip shield is completely surrounded by rubble. Subsequently, the insulating effect of rubble causes an abrupt increase in the temperatures of the in-drift components and conduction through the rubble dominates the in-drift heat transfer. The heat generated by emplaced waste transports water vapor away from the drift creating a dryout zone and redistributing pore fluids within a potentially large volume of host rock. The likelihood of water seeping into the drift is strongly affected by the extent and duration of the dryout zone. Model results showing the temporal variability of the dryout zone, both in the host rock and the rubble pile, will be presented. Sensitivity analyses show that the in-drift thermohydrologic conditions are sensitive to the thermal properties of the rubble and the rate of drift degradation. This poster in an independent product of CNWRA and does not necessarily reflect the view or regulatory position of Nuclear Regulatory Commission.
DE: 1829 Groundwater hydrology
DE: 1875 Unsaturated zone
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting