THERMAL CONDUCTIVITY OF UO$sub 2$
Thermal conductivity was measured on several types of UO/sub 2/ specimens, both irradiated and nonirradiated. Variations in fabrication conditions can result in wide differences in thermal conductivity. High density, nonsintered, crystal compacts have a low, nearly temperatureindependent conductivity while sintered polycrystalline UO/sub 2/ exhibits typical decreasing conductivity inversely proportional to temperature. Single crystals of UO/sub 2/ display increasing heat transfer rates at temperatures above 700 deg C, probably as a result of contributions by radiation and other energy transfer mechanisms. Irradiation of sintered UO/sub 2/ at less than 100 deg C causes a decrease in thermal conduct ity to 50% or less of its nonirradiated value near room tempernture. As the temperature is raised, conductivity tends toward the corresponding nonirradiated values; pr nounced stages of recovery'' occur near 150 and 400 deg C, and less definltely near 800 deg C. This thermal annealing co incides with UO/sub 2/ crystal lattice parameter recovery, and appears to be associated with crystal lattice damage sustained during irradiation. Above 1000 deg C, no significant influence of irradiation on sintered polycrystalline UO/sub 2/ was observed. (auth)
- Research Organization:
- General Electric Co. Hanford Atomic Products Operation, Richland, Wash.; Battelle Memorial Inst., Columbus, Ohio
- DOE Contract Number:
- AT(45-1)-1350
- NSA Number:
- NSA-17-011258
- OSTI ID:
- 4727635
- Report Number(s):
- HW-69945
- Country of Publication:
- United States
- Language:
- English
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