HR: 0830h
AN: H21D-0836    [PDF]
TI: Effects of Drift Degradation on Environmental Conditions in Drifts
AU: * Manepally, C
EM: cmanepally@swri.org
AF: CNWRA - Southwest Research Institute, P.O. Drawer 28510, San Antonio, TX 78228-0510 United States
AU: Fedors, R W
EM: randall.fedors@swri.org
AF: CNWRA - Southwest Research Institute, P.O. Drawer 28510, San Antonio, TX 78228-0510 United States
AU: Adams, G R
EM: george.adams@swri.org
AF: CNWRA - Southwest Research Institute, P.O. Drawer 28510, San Antonio, TX 78228-0510 United States
AU: Green, S T
EM: steven.green@swri.org
AF: CNWRA - Southwest Research Institute, P.O. Drawer 28510, San Antonio, TX 78228-0510 United States
AB: Drift degradation is anticipated to significantly influence the environment inside waste emplacement drifts at the proposed repository for high level waste at Yucca Mountain, Nevada. This poster presents the calculated effects of drift degradation on the waste package and drip shield temperatures. Natural backfilling caused by degradation of the fractured tuff wallrock may occur gradually throughout the repository drifts, with all drifts estimated to be backfilled within 1,000 years after closure. Model results indicate prominent increases in waste package and drip shield temperatures due to the insulating effect of the backfill material. An algorithm linking drift degradation to estimates of waste package and drip shield temperature will be presented. Components of the different in-drift heat-transfer processes-including, conduction, convection and thermal radiation-are analyzed for relative importance. The results indicate that thermal radiation and convection dominate the in-drift heat transfer in the absence of drift degradation effects. In the case where drift degradation created a natural backfill, conduction through the backfill was the dominant heat transfer process. Furthermore, sensitivity analyses showed that the in-drift temperatures were very sensitive to the assumed thermal properties of the natural backfill. Ongoing numerical modeling that incorporates hydrologic effects on environmental conditions will also be discussed. This poster is an independent product of the CNWRA and does not necessarily reflect the view or regulatory position of the U.S. Nuclear Regulatory Commission.
DE: 1829 Groundwater hydrology
SC: Hydrology [H]
MN: 2003 Fall Meeting