Hostname: page-component-78c5997874-m6dg7 Total loading time: 0 Render date: 2024-11-09T03:32:28.021Z Has data issue: false hasContentIssue false

Localized Dryout: an Approach for Managing the Thermal-Hydrological Effects of Decay Heat at Yucca Mountain

Published online by Cambridge University Press:  15 February 2011

Thomas A. Buscheck
Affiliation:
Earth Sciences Division, LLNL, (all at Lawrence Livermore National Laboratory, L-206, P.O. Box 808, Livermore, CA 94551)
John J. Nitao
Affiliation:
Earth Sciences Division, LLNL, (all at Lawrence Livermore National Laboratory, L-206, P.O. Box 808, Livermore, CA 94551)
Lawrence D. Ramspot
Affiliation:
TRW (all at Lawrence Livermore National Laboratory, L-206, P.O. Box 808, Livermore, CA 94551)
Get access

Abstract

For a nuclear waste repository in the unsaturated zone at Yucca Mountain, there are two thermal loading approaches to using decay heat constructively-that is, to substantially reduce relative humidity and liquid flow near waste packages for a considerable time, and thereby limit waste package degradation and radionuclide dissolution and release. “Extended dryout” achieves these effects with a thermal load high enough to generate large-scale (coalesced) rock dryout. “Localized dryout”(which uses wide drift spacing and a thermal load too low for coalesced dryout) achieves them by maintaining a large temperature difference between the waste package and drift wail; this is done with close waste package spacing (generating a high line-heat load) and/or low-thermal-conductivity backfill in the drift. Backfill can greatly reduce relative humidity on the waste package in both the localized and extended dryout approaches. Besides using decay heat constructively, localized dryout reduces the possibility that far-field temperature rise and condensate buildup above the drifts might adversely affect waste isolation.

Type
Research Article
Copyright
Copyright © Materials Research Society 1996

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Buscheck, T.A., and Nitao, J.J., “Repository-Heat-Driven Hydrothermal Flow at Yucca Mountain, Part I: Modeling and Analysis,” Nuclear Technology, Vol.104, No. 3, pp. 418448 (1993).Google Scholar
2. Buscheck, T.A., and Nitao, J.J., “The Impact of Buoyant Gas-Phase Flow and Heterogeneity on Thermo-Hydrological Behavior at Yucca Mountain,” American Nuclear Society, La Grange Park, IL, Proceedings Fifth International High-Level Radioactive Waste Management Conference, Las Vegas, NV, May 1994. Also UCRL-JC-115351, Lawrence Livermore National Laboratory, Livermore, CA (1994).Google Scholar
3. Buscheck, T.A. and Nitao, J.J., “The Importance of Thermal Loading Conditions to Waste Package Performance at Yucca Mountain,” Materials Research Society, Pittsburgh, PA, Proceedings Materials Research Society XVIII International Symposium on the Scientific Basis for Nuclear Waste Management, Oct. 23–27, 1994. Also UCRL-JC-116429, Lawrence Livermore National Laboratory, Livermore, CA (1994).Google Scholar
4. Buscheck, T.A., and Nitao, J.J., “Thermal-Hydrological Analysis of Large-Scale Thermal Tests in the Exploratory Studies Facility at Yucca Mountain,” UCRL-ID-121791, Lawrence Livermore National Laboratory, Livermore, CA (1995).Google Scholar
5. Stahl, D., McCoy, J.K., and McCright, R.D., “Impact of Thermal Loading on Waste Package Material Performance,” Material Research Society, Pittsburgh, PA, Proceedings Material Research Society XVIII Symposium on the Scientific Basis for Nuclear Waste Management, Oct. 23–27 (1994).Google Scholar
6. Jones, D.A., Principles and Prevention of Corrosion, Macmillan Publishing Company, New York (1992).Google Scholar
7. Nitao, J.J., “V-TOUGH - An Enhanced Version of the TOUGH Code for the Thermal and Hydrologic Simulation of Large-Scale Problems in Nuclear Waste Isolation,” UCID-21954, Lawrence Livermore National Laboratory, Livermore, CA (1989).Google Scholar
8. Pruess, K., “TOUGH User's Guide,” NUREG/CR-4645, Nuclear Regulatory Commission (1987).Google Scholar
9. Nitao, J.J., “Reference Manual for the NUFT Flow and Transport Code, Version 1.0,” UCRL-ID-113520 Lawrence Livermore National Laboratory, Livermore, CA (1995).Google Scholar
10. Peters, R.R., Klavetter, E.A., Hall, I.J., Blair, S.C., Hellers, P.R., and Gee, G.W., “Fracture and Matrix Hydrologic Characteristics of Tuffaceous Materials from Yucca Mountain, Nye County, Nevada,” SAND84–1471, Sandia National Laboratories, Albuquerque, NM (1984).Google Scholar