Thermal conductivity of bentonite/quartz high-level waste package backfill
A mixture of bentonite clay and quartz sand is being considered for use as a waste-package backfill, the material placed between a radioactive-waste canister and the repository host rock. Compacts of bentonite/quartz with weight-percent ratios of 100/0, 70/30, 50/50 and 30/70 were made at room temperature under a pressure of 100 MPa (15 ksi). Upon initial heating, the thermal conductivity of the 70/30 compact rose from 1.20 W/m.K at 298 K to 1.32 W/m.K at 373 K. After further heating to 473 K, it fell to 1.10 W/m.K, reflecting the loss of interlamellar water from the bentonite. The conductivity of the now-dehydrated compacts displayed conductivities of 0.59, 1.06 and 0.83 W/m.K, respectively, at 298 K. Measured densities ranged from 1.98 to 2.12 g/cc. Combined geometric-mean and Maxwell models for thermal conduction in composite systems predict the measured results reasonably well. An analysis of the impact of backfills on high-level waste package design indicates that no significant thermal penalty is imposed.
- Research Organization:
- Sandia National Labs., Albuquerque, NM
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 5939989
- Report Number(s):
- CONF-821107-Pt.1; TRN: 83-018880
- Journal Information:
- Mater. Res. Soc. Symp. Proc.; (United States), Vol. 15; Conference: 6. international symposium on the scientific basis for radioactive waste management (Materials Research Society), Boston, MA, USA, 1 Nov 1982
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
BACKFILLING
MATERIALS TESTING
BENTONITE
THERMAL CONDUCTIVITY
QUARTZ
RADIOACTIVE WASTE DISPOSAL
EXPERIMENTAL DATA
CHALCOGENIDES
CLAYS
DATA
INFORMATION
MANAGEMENT
MINERALS
NUMERICAL DATA
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SILICON COMPOUNDS
SILICON OXIDES
TESTING
THERMODYNAMIC PROPERTIES
WASTE DISPOSAL
WASTE MANAGEMENT
052002* - Nuclear Fuels- Waste Disposal & Storage
360603 - Materials- Properties