%0 Journal Article
%A Murphy, Gabriel L.
%A Bazarkina, Elena
%A Rossberg, André
%A Silva, Clara L.
%A Amidani, Lucia
%A Bukaemskiy, Andrey
%A Thümmler, Robert
%A Klinkenberg, Martina
%A Henkes, Maximilian
%A Marquardt, Julien
%A Lessing, Jessica
%A Svitlyk, Volodymyr
%A Hennig, Christoph
%A Kvashnina, Kristina O.
%A Huittinen, Nina
%T The role of redox and structure on grain growth in Mn-doped UO2
%J Communications materials
%V 5
%N 1
%@ 2662-4443
%C London
%I Springer Nature
%M FZJ-2025-00486
%P 274
%D 2024
%X Mn-doped UO2 is considered a potential advanced nuclear fuel due to ameliorated microstructural grain growth compared to non-doped variants. However, recent experimental investigations have highlighted limitations in grain growth apparently arising from misunderstandings of its redox-structural chemistry. To resolve this, we use synchrotron X-ray diffraction and spectroscopy measurements supported by ab initio calculations to cross-examine the redox and structural chemistry of Mn-doped UO2 single crystal grains and ceramic specimens. Measurements reveal Mn enters the UO2 matrix divalently as with the additional formation of fluorite Mn+2O in the bulk material. Extended X-ray absorption near edge structure measurements unveil that during sintering, the isostructural relationship between fluorite UO2 and Mn+2O results in inadvertent interaction and subsequent incorporation of diffusing U species within MnO, rather than neighbouring UO2 grains, inhibiting grain growth. The investigation consequently highlights the significance of considering total redox-structural chemistry of main and minor phases in advanced ceramic material design.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:001381203000005
%R 10.1038/s43246-024-00714-x
%U https://juser.fz-juelich.de/record/1037139