Effects of thermal gradients in oxide fuels (LWBR Development Program)

Technical Report · Wed Feb 28 23:00:00 EST 1973

OSTI ID:6742072

Cohen, I

ThO/sub 2/ and ThO/sub 2/-10 wt% UO/sub 2/ compositions have been studied as part of development work for the Light Water Breeder Reactor (LWBR). Thermal gradient experiments, designed to simulate conditions encountered during irradiation, were conducted to study the microstructural changes which occur in these fields. Thermal gradient runs with ThO/sub 2/-10 wt% UO/sub 2/ annular pellets were made at ID temperatures of 2700 to 3000/sup 0/C and at OD temperatures of 1300 to 1500/sup 0/C. Runs with ThO/sub 2/ annular pellets were made with an ID temperature of 2700/sup 0/C and OD temperatures of 1550 to 1600/sup 0/C. The origin of lenticular shaped pores generating columnar grains was discussed. The velocity of pore movement was measured and compared with analytical predictions. Grain growth measurements were made and activation energies were calculated. The grain size-time relationship could be expressed by the equations: D/sup 4/ - D/sup 4//sub 0/ = kt/sup 0.93/e/sup-88,000.RT/ (THO/sub 2/) and D/sup 4/ - D/sup 4//sub 0/ = kt/sup 0.90/e/sup -102,000/RT/ (THO/sub 2/ - 10 wt % UO/sub 2/). (NSA 28: 774)

• Research Organization: Bettis Atomic Power Lab., Pittsburgh, PA (USA)
• DOE Contract Number: AT(11-1)-GEN-14
• OSTI ID: 6742072
• Report Number(s): WAPD-TM-1092
• Country of Publication: United States
• Language: English

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