The analysis of repository-heat-driven hydrothermal flow at Yucca Mountain

Conference · Fri Dec 31 04:00:00 EST 1993

OSTI ID:60891

Buscheck, T A; Nitao, J J ^[1]

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1. Lawrence Livermore National Lab., CA (United States)

To safely and permanently store high-level nuclear waste, the potential Yucca Mountain repository site must mitigate the release and transport of radionuclides for tens of thousands of years. In the failure scenario of greatest concern, water would contact the waste package (WP), accelerate its failure rate, and eventually transport radionuclides to the water table. In a concept called the {open_quotes}extended-dry repository,{close_quotes} decay heat arising from radioactive waste extends the time before liquid water can contact a WP. Recent modeling and theoretical advances in nonisothermal, multiphase fracture-matrix flow have demonstrated (1) the critical importance of capillary pressure disequilibrium between fracture and matrix flow, and (2) that radioactive decay heat plays a dominant role in the ability of the engineered and natural barriers to contain and isolate radionuclides. Our analyses indicate that the thermo-hydrological performance of both the unsaturated zone (UZ) and saturated zone (SZ) will be dominated by repository-heat-driven hydrothermal flow for tens of thousands of years. For thermal loads resulting in extended-dry repository conditions, UZ performance is primarily sensitive to the thermal properties and thermal loading conditions and much less sensitive to the thermal properties and thermal loading conditions and much less sensitive to the highly spatially and temporally variable ambient hydrologic properties and conditions. The magnitude of repository-heat-driven buoyancy flow in the SZ is far more dependent on the total mass of emplaced spent nuclear fuel (SNF) than on the details of SNF emplacement, such as the Areal Power Density [(APD) expressed in kW/acre] or SNF age.

• Research Organization: American Nuclear Society, La Grange Park, IL (United States); American Society of Civil Engineers, New York, NY (United States)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 60891
• Report Number(s): CONF-930408--Vol.1
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
54 ENVIRONMENTAL SCIENCES
CAPILLARY FLOW
FLUID FLOW
GEOLOGIC FRACTURES
HIGH-LEVEL RADIOACTIVE WASTES
HYDROLOGY
HYDROTHERMAL ALTERATION
RADIOACTIVE WASTE DISPOSAL
RADIONUCLIDE MIGRATION
SITE CHARACTERIZATION
TEMPERATURE DEPENDENCE
THERMODYNAMICS
UNDERGROUND DISPOSAL
WASTE-ROCK INTERACTIONS
YUCCA MOUNTAIN
Yucca Mountain Project