In-pile thermal conductivity of selected ThO/sub 2/--UO/sub 2/ fuels at low depletions (LWBR Development Program)

Technical Report · Thu May 01 04:00:00 EDT 1969

OSTI ID:6757275

Jacobs, D C

The in-pile thermal conductivities of selected ThO/sub 2/-UO/sub 2/, fuel materials were determined by direct measurement using an in-pile extension of the radial heat-flow technique. The tests incorporated ThO/sub 2/ + 3.1 wt % UO/sub 2/, ThO/sub 2/ + 7.7 wt % UO/sub 2/, ThO/sub 2/ + 10 wt % UO/sub 2/ and UO/sub 2/ specimens. The microstructure, stoichiometry, density, impurity content, and unirradiated thermal conductivity were determined for each fuel material. The test results showed no statistically significant differences between the in-pile and unirradiated thermal conductivities for steady-state operation for the UO/sub 2/ specimens at 600 < or = T < or = 1000/sup 0/C, at a burnup of up to 5.6 x 10/sup 18/ fission/cm/sup 3/ and for the ThO/sub 2/-UO/sub 2/ specimens at 400 < or = T < or = 1000/sup 0/C at a burnup of up to 1.4 x 10/sup 19/ fission/cm/sup 3/. The in-pile conductivities were slightly, but significantly, greater than the unirradiated conductivities at 1000 < T < or = 1300/sup 0/C for the UO/sub 2/ specimens and at 1000 < T < or = 1700/sup 0/C for the ThO/sub 2/-UO/sub 2/ specimens. However, this is considered to be an experimental anomaly and is not taken as a meaningful enhancement of in-pile conductivity. The maximum depletions achieved in these tests are one to two orders of magnitude less than typical in-service depletions. Hence, the test results do not reflect any possible changes in conductivity by the accumulation of fission products and the formation of fission gas bubbles. (NSA 23: 36271)

• Research Organization: Bettis Atomic Power Lab., Pittsburgh, PA (USA)
• DOE Contract Number: AT(11-1)-GEN-14
• OSTI ID: 6757275
• Report Number(s): WAPD-TM-758
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
&amp; Refractories-- Physical Properties
ACTINIDE COMPOUNDS
BREEDER REACTORS
BURNUP
CHALCOGENIDES
CRYSTAL STRUCTURE
FUEL PELLETS
LWBR TYPE REACTORS
MICROSTRUCTURE
OXIDES
OXYGEN COMPOUNDS
PELLETS
PHYSICAL PROPERTIES
REACTORS
STOICHIOMETRY
THERMAL CONDUCTIVITY
THERMAL REACTORS
THERMODYNAMIC PROPERTIES
THORIUM COMPOUNDS
THORIUM OXIDES
URANIUM COMPOUNDS
URANIUM DIOXIDE
URANIUM OXIDES
WATER COOLED REACTORS
WATER MODERATED REACTORS