Grain growth and pore coarsening in dense nano-crystalline UO2+x fuel pellets
- Rensselaer Polytechnic Institute, Troy, NY (United States)
- Argonne National Lab. (ANL), Lemont, IL (United States)
- Argonne National Lab. (ANL), Lemont, IL (United States); Xi'an Jiaotong Univ., Shaanxi (China)
Abstract Dense nano‐sized UO 2+ x pellets are synthesized by spark plasma sintering with controlled stoichiometries (UO 2.03 and UO 2.11 ) and grain sizes (~100 nm), and subsequently isothermally annealed to study their effects on grain growth kinetics and microstructure stability. The grain growth kinetics is determined and analyzed focusing on the interaction between grain boundary migration, pore growth, and coalescence. Grains grow much bigger in nano‐sized UO 2.11 than UO 2.03 upon thermal annealing, consistent with the fact that hyper‐stoichiometric UO 2+ x is beneficial for sintering due to enhanced U ion diffusion from excessive O ion interstitials. The activation energies of the grain growth for UO 2.03 and UO 2.11 are determined as ~1.0 and ~2.0 eV, respectively. As compared with the micrometer‐sized UO 2 in which volumetric diffusion dominates the grain coarsening with an activation energy of ~3.0 eV, the enhanced grain growth kinetics in nano‐sized UO 2+ x suggests that grain boundary diffusion controls grain growth. The higher activation energy of more hyper‐stoichiometric nano‐sized UO 2.11 may be attributed to the excessive O interstitials pinning grain boundary migration.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Nuclear Energy (NE), Nuclear Energy Advanced Modeling and Simulation (NEAMS); USDOE Office of Nuclear Energy (NE), Nuclear Energy University Programs (NEUP); National Science Foundation (NSF); USDOE
- Grant/Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1373755
- Alternate ID(s):
- OSTI ID: 1401771
- Journal Information:
- Journal of the American Ceramic Society, Vol. 100, Issue 6; ISSN 0002-7820
- Publisher:
- American Ceramic SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Kinetic study on the grain growth of PuO 2 nanocrystals
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journal | January 2019 |
Consolidation of commercial-size UO2 fuel pellets using spark plasma sintering and microstructure/microchemical analysis
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journal | July 2018 |
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