Thermal expansion and steam oxidation of uranium mononitride analysed via in situ neutron diffraction

Abstract
In situ neutron powder diffraction experiments are applied to physical, kinetic, and microstructural characterization of uranium mononitride as a promising light water reactor fuel material. The temperature-variable coefficient of thermal expansion and isotropic Debye Waller factors are obtained by sequential Rietveld refinement over 499–1873 K. Oxidation of a UN pellet (95.2% density) under flow of 11 mg/min D2O is observed to initiate above 623 K and the rate increases by a factor of approximately 10 from 673 to 773 K, with activation energy 50.6 ± 1.3 kJ/mol; uranium oxide is the only solid corrosion product. Crown Copyright © 2022 Published by Elsevier B.V.
Description
The authors acknowledge contributions made by Chris Baldwin, Dr. Deborah Wakeham and Dr Daniel J. Gregg in the planning and execution of experiments; funding for beamtime proposals P6904 and P8186 at the Australian Centre for Neutron Scattering; CG and MRW: EPSRC funding under grant no. EP/P005101/1; CG: UNSW Sydney Women in Engineering Travel Award; EGO and PAB: funding from ANSTO and the Sir William Tyree Foundation.
Keywords
Thermal expansion, Steam, Oxidation, Uranium, Neutron diffraction, Water cooled reactors, Nuclear fuels
Citation
Liu, J., Gasparrini, C., White, J. T., Johnson, K., Lopes, D. A., Peterson, V. K., Studer, A., Griffiths, G. J., Lumpkin, G. R., Wenman, M. R., Burr, P. A., Sooby, E. S., & Obbard, E. G. (2023). Thermal expansion and steam oxidation of uranium mononitride analysed via in situ neutron diffraction. Journal of Nuclear Materials, 575, 154215. doi:10.1016/j.jnucmat.2022.154215
Collections