Comparison of uranium dissolution rates from spent fuel and uranium dioxide
- Lawrence Livermore National Lab., CA (United States)
- Pacific Northwest Lab., Richland, WA (United States)
Two similar sets of dissolution experiments, resulting from a statistical experimental design were performed in order to examine systematically the effects of temperature (25--75{degree}C), dissolved oxygen (0.002-0.2 atm overpressure), pH (8--10) and carbonate concentrations (2--200 {times} 10{sup {minus}4} molar) on aqueous dissolution of UO{sub 2} and spent fuel. The average dissolution rate was 8.6 mg/m{sup 2}{center_dot}day for UO{sub 2} and 3.1 mg/m{sup 2}{center_dot}day for spent fuel. This is considered to be an insignificant difference; thus, unirradiated UO{sub 2} and irradiated spent fuel dissolved at about the same rate. Moreover, regression analyses indicated that the dissolution rates of UO{sub 2} and spent fuel responded similarly to changes in pH, temperature, and carbonate concentration. However, the two materials responded very differently to dissolved oxygen concentration. Approximately half-order reaction rates with respect to oxygen concentration were found for UO{sub 2} at all conditions tested. At room temperature, spent fuel dissolution (reaction) rates were nearly independent of oxygen concentration. At 75{degree}C, reaction orders of 0.35 and 0.73 were observed for spent fuel, and there was some indication that the reaction order with respect to oxygen concentration might be dependent on pH and/or carbonate concentration as well as on temperature.
- Research Organization:
- Lawrence Livermore National Lab., CA (United States); Pacific Northwest Lab., Richland, WA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-48; AC06-76RL01830
- OSTI ID:
- 10163296
- Report Number(s):
- UCRL-JC--115355; CONF-940553--72; ON: DE94014751
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
053002
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400702
CHEMICAL REACTION KINETICS
COMPARATIVE EVALUATIONS
DISSOLUTION
EXPERIMENTAL DATA
OXYGEN
PH VALUE
PROPERTIES OF RADIOACTIVE MATERIALS
RADIOACTIVE EFFLUENTS
SPENT FUELS
TEMPERATURE DEPENDENCE
URANIUM DIOXIDE
WASTE DISPOSAL AND STORAGE