Effects of local cesium concentrations on mixed-oxide fuel behavior

Conference · Sat Jan 01 04:00:00 EST 1977

OSTI ID:6720930

Karnesky, R. A.

Local peaks in cesium concentrations were found to influence the thermal-mechanical behavior of mixed-oxide fuel pins at high burnup. A prototypic fuel pin was irradiated in EBR-II at a peak linear power of approximately 400 W/cm (12 kW/ft) with peak cladding temperatures of approximately 540/sup 0/C (1000/sup 0/F) to a peak burnup of approximately 8.7 at. %. The mixed-oxide pellet fuel (75 wt % UO/sub 2/, 25% PuO/sub 2/) had an initial oxygen-to-metal ratio of 1.956 and a planar smeared density of 90% of theoretical. The pin was clad with .041 cm (0.016 in.) thick, .635 cm (0.250 in.) diameter, solution-annealed type 316 stainless steel. In the region of the upper UO/sub 2/ insulator the high cesium concentration and attendant cesium-urania reaction zone are found to be restricted to a narrow region on the circumference of the first insulator pellet. This reaction zone resulted in extensive fragmentation of the insulator pellet approximately .24 cm (.1 in.) above the fuel-insulator interface. Densification of the insulator pellet fragment adjacent to the fuel column appears to have occurred and may be due to increased temperatures resulting from the increased thermal resistance of the crack. The cesium-urania reaction region appears to consist of two zones, a high density area where the urania insulator pellet has undergone grain boundary attack and dissolution and a lower density zone with a more porous cesium-urania reaction product.

• Research Organization: Hanford Engineering Development Lab., Richland, WA (USA)
• DOE Contract Number: EY-76-C-14-2170
• OSTI ID: 6720930
• Report Number(s): HEDL-SA-1306S; CONF-771109-106
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
210500* -- Power Reactors
Breeding
ACTINIDE COMPOUNDS
ALKALI METALS
BREEDER REACTORS
BURNUP
CESIUM
CHALCOGENIDES
CHEMICAL REACTIONS
ELEMENTS
EPITHERMAL REACTORS
FAST REACTORS
FBR TYPE REACTORS
FISSION PRODUCTS
FRAGMENTATION
FUEL DENSIFICATION
FUEL ELEMENTS
FUEL PELLETS
FUEL PINS
FUELS
ISOTOPES
LIQUID METAL COOLED REACTORS
LMFBR TYPE REACTORS
METALS
OXIDES
OXYGEN COMPOUNDS
PELLETS
PLUTONIUM COMPOUNDS
PLUTONIUM DIOXIDE
PLUTONIUM OXIDES
RADIOACTIVE MATERIALS
REACTOR COMPONENTS
REACTORS
SOLID FUELS
TRANSURANIUM COMPOUNDS
URANIUM COMPOUNDS
URANIUM DIOXIDE
URANIUM OXIDES