May 2024

Journal

Raman spectroscopy of uranium nitride kernels

By:
Lopez Honorato, Eddie ; Liang, Liangbo ; Kurley III, James M; Montoya, Katherine I; Cureton, William F; Siebert, Rachel; Hunt, Rodney D; Capps, Nathan A; Nelson, Andrew T
Journal Name:
Journal of Nuclear Materials
Page Number:
155050
Volume:
595
Publication Date:
May 3, 2024
View DOI Listing:
https://doi.org/10.1016/j.jnucmat.2024.155050

Abstract

Uranium nitride is an advanced fuel candidate for a wide variety of advanced nuclear reactors. This work summarizes the first characterization of UN kernels by Raman spectroscopy. First-principles density functional theory calculations were performed to predict the Raman spectra of uranium sesquinitride (U2N3), uranium dinitride (UN2), uranium mononitride (UN), uranium monocarbide (UC), as well as U-N-C (UN1-xCx) and a U-N-C-O mixture. A core–shell structure was identified by scanning electron microscopy and Raman spectroscopy imaging. A signal at ∼500 cm−1 was identified on the periphery of the core-shell structure, possibly corresponding to U2N3 and/or UN2. This signal broadens and shifts to 470 cm−1 because of the formation of UNC, UNCO or U2N3+x structures. The culmination of this work demonstrates the feasibility of using Raman spectroscopy to identify variations in composition and phases in UN kernels.