Influence of pO2 on the fabrication of UO2 fuel doped with a niobium oxide-based redox couple
Abstract
The influence of pO2 on the fabrication of UO2 fuel doped with a niobium oxides-based redox buffer was investigated. UO2 powder doped with 1.6 wt% of Nb2O5/NbO2 was prepared, pressed into pellets, and sintered at 1700 °C under three atmospheres with different pO2 values. The densification behavior and resulting microstructures were systematically characterized. Sintering under a reducing atmosphere promoted effective densification but led to the reduction of niobium oxides. In contrast, under an oxidizing atmosphere, densification started at higher temperature and proceeded at a higher rate. However, the final density was lower due to increased porosity and partial dopant loss, likely associated with the formation of a liquid phase under the corresponding temperature and pO2 conditions. To address these limitations, a two-step fabrication route was developed. The first step involved sintering under a reducing atmosphere to achieve high densification. The second step consisted of a post-sintering heat treatment at lower temperature under controlled oxidizing conditions to re-oxidize the niobium oxide inclusions while avoiding liquid phase formation. This approach enabled the fabrication of dense UO2 fuel incorporating the UNb2O7/NbO2 redox couple, thereby combining adequate densification with controlled chemical stabilization of the buffering inclusions.
Related
- Diatomite-Templated Fabrication of Porous N, S-Co-Doped Carbon as High-Performance Catalyst for Oxygen Reduction
- Molecular-Level Structure Regulation via Sequential Pre-Crosslinking and Friedel-Crafts Hypercrosslinking: Fabrication of Bimetallic Doped Porous Carbon Electrocatalysts
- Design and fabrication of graphene oxide-based nanocomposites with tuneable morphological properties for advanced supercapacitor applications
- Fabrication of superhydrophobic and superoleophilic copper oxide nanostructures without organic modifiers for oil–water separation
- Creating percolating Li diffusion pathways via Ge substitution enables the fabrication of thick-electrode oxide all-solid-state batteries
BibTeX
@article{gobert2026influence,
title = {{Influence of pO2 on the fabrication of UO2 fuel doped with a niobium oxide-based redox couple}},
author = {Shalane Gobert and Vincent Klosek and F. Audubert and Jean-Marc Heintz},
journal = {Journal of the European Ceramic Society},
year = {2026},
month = oct,
doi = {10.1016/j.jeurceramsoc.2026.118865},
url = {https://u-bordeaux.hal.science/hal-05761227v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Influence of pO2 on the fabrication of UO2 fuel doped with a niobium oxide-based redox couple
AU - Shalane Gobert
AU - Vincent Klosek
AU - F. Audubert
AU - Jean-Marc Heintz
PY - 2026
DA - 2026/10/05
JO - Journal of the European Ceramic Society
DO - 10.1016/j.jeurceramsoc.2026.118865
UR - https://u-bordeaux.hal.science/hal-05761227v1
AB - The influence of pO2 on the fabrication of UO2 fuel doped with a niobium oxides-based redox buffer was investigated. UO2 powder doped with 1.6 wt% of Nb2O5/NbO2 was prepared, pressed into pellets, and sintered at 1700 °C under three atmospheres with different pO2 values. The densification behavior and resulting microstructures were systematically characterized. Sintering under a reducing atmosphere promoted effective densification but led to the reduction of niobium oxides. In contrast, under an oxidizing atmosphere, densification started at higher temperature and proceeded at a higher rate. However, the final density was lower due to increased porosity and partial dopant loss, likely associated with the formation of a liquid phase under the corresponding temperature and pO2 conditions. To address these limitations, a two-step fabrication route was developed. The first step involved sintering under a reducing atmosphere to achieve high densification. The second step consisted of a post-sintering heat treatment at lower temperature under controlled oxidizing conditions to re-oxidize the niobium oxide inclusions while avoiding liquid phase formation. This approach enabled the fabrication of dense UO2 fuel incorporating the UNb2O7/NbO2 redox couple, thereby combining adequate densification with controlled chemical stabilization of the buffering inclusions.
SN - 0955-2219
SN - 1873-619X
ER -