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Corrosion mechanisms of spent fuel under oxidizing conditions

Conference ·
OSTI ID:542061
The release of {sup 99}Tc can be used as a reliable marker for the extent of spent oxide fuel reaction under unsaturated high-drip-rate conditions at 90{degrees}C. Evidence from leachate data and from scanning and transmission electron microscopy (SEM and TEM) examination of reacted fuel samples is presented for radionuclide release, potential reaction pathways, and the formation of alteration products. In the ATM-103 fuel, 0.03 of the total inventory of {sup 99}Tc is released in 3.7 years under unsaturated and oxidizing conditions. Two reaction pathways that have been identified from SEM are (1) through-grain dissolution with subsequent formation of uranyl alteration products, and (2) grain-boundary dissolution. The major alteration product identified by x-ray diffraction (XRD) and SEM, is Na-boltwoodite, Na[(UO{sub 2})(SiO{sub 3}OH)]{lg_bullet}H{sub 2}O, which is formed from sodium and silicon in the water leachant.
Research Organization:
Argonne National Lab., IL (United States)
Sponsoring Organization:
USDOE Office of Environmental Restoration and Waste Management, Washington, DC (United States)
DOE Contract Number:
W-31109-ENG-38
OSTI ID:
542061
Report Number(s):
ANL/CMT/CP--93030; CONF-970902--; ON: DE98000644
Country of Publication:
United States
Language:
English