Abstract
Oxygen exchange reactions performed on PuO2 suggest the reaction is influenced by at least three mechanisms: an internal chemical reaction, surface mobility of active species/defects, and surface exchange of gaseous oxygen with lattice oxygen. Activation energies for the surface mobility and internal chemical reaction are presented. Determining which mechanism is dominant appears to be a complex function including at least specific surface area and temperature. Thermal exposure may also impact the oxygen exchange reaction by causing reductions in the specific surface area of PuO2. Previous CeO2 surrogate studies exhibit similar behavior, confirming that CeO2 is a good qualitative surrogate for PuO2, in regards to the oxygen exchange reaction. Comparison of results presented here with previous work on the PuO2 oxygen exchange reaction allows complexities in the previous work to be explained. These explanations allowed new conclusions to be drawn, many of which confirm the conclusions presented here.
Original language | English |
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Pages (from-to) | 770-777 |
Number of pages | 8 |
Journal | Journal of Nuclear Materials |
Volume | 467 |
DOIs | |
State | Published - Dec 1 2015 |
Funding
The University of Dayton Research Institute was funded by the U.S. Department of Energy under contract #: DE-NE0000422 . Oak Ridge National Laboratory was funded by the U.S. Department of Energy under contract #: DE-AC0500OR22725 . The authors would like to acknowledge Raymond Vedder from Oak Ridge National Laboratory for some technical assistance with performing the oxygen exchange experiments. Additional thanks goes to Dr. Michael Stoll and Lia Brodnax of Los Alamos National Laboratory for useful discussions regarding the impacts of this work to the 238 PuO 2 heat source program.
Keywords
- Internal chemical reaction
- Kinetics
- Oxygen exchange
- Plutonium (IV) oxide
- Surface exchange
- Surface mobility