EVALUATION OF IRRADIATED ALUMINA-COATED UO$sub 2$ PARTICLES DISPERSED IN GRAPHITE SPHERES

Technical Report · Thu Mar 22 04:00:00 EST 1962

OSTI ID:4796483

Burian, R J; Ritzman, R L; Gates, J E; Dickerson, R F

Two graphite spheres fueled with alumina-coated UO/sub 2/ particles were irradiated in Capsule SP-5 in the Battelle Research Reactor at 510 to 730 deg C to fission burnups of 4.7 to 5.6% of the U/sup 235/. Initially the spheres exhibited excellent fission-gas retention. However, after a significant fuel burnup, the fission-gas release increased in a manner which indicated loss of coating integrity. Examination of the irradiated specimens indicated that about 8% of the fuel particles had cracked coatings. Cracking was strongly dependent upon radial position in the sphere. Although some radiation damage to the alumina coatings may have occurred, evidence of changes in the coatings was not observed. Factors other than radiation damsge which probably contributed to the failure of the coatings include thermal gradients in the graphite matrix during irradiation, and fission-gas pressure and stresses introduced during fabrication acting upon the inherent flaws in the brittle alumina. The graphite spheres experienced a contraction of 0.2 to 2.5% which was similar to that observed in graphites containing uncoated UO/sub 2/ particles and exposed to 5.4 x I0/sup 18/ fission fragments per cm/sup 3/. The compressive strength of the graphite did not change significantly during irradiation. (auth)

• Research Organization: Battelle Memorial Inst., Columbus, Ohio
• DOE Contract Number: W-7405-ENG-92
• NSA Number: NSA-16-015241
• OSTI ID: 4796483
• Report Number(s): BMI-1572
• Country of Publication: United States
• Language: English

Related Subjects

ABSORPTION
ALUMINUM OXIDES
BRITTLENESS
BURNUP
COATING
CRACKS
DEFECTS
DEFORMATION
DISPERSIONS
FABRICATION
FAILURES
FISSION PRODUCTS
FUELS
GASES
GRAPHITE
IRRADIATION
LOSSES
MATERIALS TESTING
METALS, CERAMICS, AND OTHER MATERIALS
NEUTRON BEAMS
PARTICLES
PRESSURE
RADIATION EFFECTS
STRESSES
TEMPERATURE
TENSILE PROPERTIES
URANIUM