Post-irradiation examination of bumper elements with high in-reactor weight losses (RM-418)

摘要

This report discusses three natural uranium, X-8001 aluminum clad, I&E Hanford production fuel elements, which were irradiated in 3363-D as part of PT-IP-262-A, were selected for detailed examination in the Radiometallurgy Laboratory. The three pieces were from the same tube and each had lost about 15 grams of cladding during irradiation. Examination was requested to determine the extent of the corrosion and whether the attack was uniform or localized. Also, measurement of the uranium fuel was requested to reveal any change that occurred during irradiation. Corrosion was general rather than localized and occurred over approximately three-fourths of the surface. In each element. about one-fourth of the surface on one side was virtually unattacked and vas probably the area that lay between the ribs of the process tube during irradiation. In one element localized attack occurred beside two of the bumpers. External aluminum cladding thicknesses ranged from 0.020 to 0.043 inch. About 0.005 inch of the spire surface vas removed by corrosion. Both internal and external dimensions of the uranium increased. The average external diameter was 0.010 inch larger and the average internal diameter vas 0.011 inch larger than the average preirradiation diameter measurements. The growth vas not uniform as ellipticity up to 0.028 inch was observed.