Total system performance assessment (TSPA-1993) for Yucca Mountain: An iterative refinement addressing scientific, regulatory, and design concerns
- Department of Energy, Las Vegas, NV (United States)
Sandia National Laboratories (SNL) (1) and Pacific Northwest Laboratory (PNL) (2) completed the first iteration of total-system performance assessment (TSPA-91) for Yucca Mountain during 1991 and 1992. TSPA-93, the successor to TSPA-91, was conducted by SNL and the Civilian Radioactive Waste Management System Management and Operating (M&O) contractor. The TSPA-93 calculations were formulated based on recommendations generated in TSPA-91. The process models used to describe contaminant mobilization and transport were expanded and the associated parameter sets were improved. Significant improvements include more sophisticated treatments of climate change and percolation flux; saturated zone flow and transport; near-field processes, such as container degradation and radionuclide mobilization; and hydrogeologic and geochemical parameter sets. New features in TSPA-93 include hydrothermal processes associated with elevated thermal loads, alternative waste container packages, and geostatistical representations of the lithologic units. Results of the analyses are shown both as releases and as individual doses, to evaluate the effect of possible changes in standards governing a high-level radioactive waste repository. 10,000-year cumulative releases are similar to those in TSPA-91, and are dominated by gaseous release of {sup 14}C. Longer term cumulative releases increase surprisingly little, with gaseous release and aqueous release more nearly equal. However, substantial individual doses are projected at very long times, as a consequence of certain features of the arid environment. Recommendations for future work to support site characterization, design, regulation assessment, and TSPAs are given, based on the results of the two studies.
- Research Organization:
- Arizona Univ., Tucson, AZ (United States). Coll. of Engineering and Mines; New Mexico State Univ., University Park, NM (United States); Waste-Management Education and Research Consortium (WERC), Las Cruces, NM (United States); USDOE, Washington, DC (United States)
- OSTI ID:
- 111733
- Report Number(s):
- CONF-940225--Vol.1
- Country of Publication:
- United States
- Language:
- English
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