Smith Hannah, Townsend Luke T, Mohun Ritesh, Cordara Théo, Stennett Martin C, Mosselmans J Frederick W, Kvashnina Kristina, Corkhill Claire L
NucleUS Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield, Sheffield, UK.
Diamond Light Source, Harwell Science and Innovation Campus, Didcot, UK.
Commun Chem. 2022 Dec 1;5(1):163. doi: 10.1038/s42004-022-00784-3.
Advanced Cr-doped UO fuels are essential for driving safe and efficient generation of nuclear energy. Although widely deployed, little is known about their fundamental chemistry, which is a critical gap for development of new fuel materials and radioactive waste management strategies. Utilising an original approach, we directly evidence the chemistry of CrO-doped UO. Advanced high-flux, high-spectral purity X-ray absorption spectroscopy (XAS), corroborated by diffraction, Raman spectroscopy and high energy resolved fluorescence detection-XAS, is used to establish that Cr directly substitutes for U, accompanied by U and oxygen vacancy charge compensation. Extension of the analysis to heat-treated simulant nuclear fuel reveals a mixed Cr oxidation state, with Cr in more than one physical form, explaining the substantial discrepancies that exist in the literature. Successful demonstration of this analytical advance, and the scientific underpinning it provides, opens opportunities for an expansion in the range of dopants utilised in advanced UO fuels.
先进的铬掺杂二氧化铀燃料对于推动安全高效的核能发电至关重要。尽管已广泛应用，但对其基础化学性质却知之甚少，这是新型燃料材料和放射性废物管理策略发展的关键差距。我们采用一种原创方法，直接证明了铬掺杂二氧化铀的化学性质。先进的高通量、高光谱纯度的X射线吸收光谱（XAS），辅以衍射、拉曼光谱和高能分辨荧光检测-XAS，用于确定铬直接替代铀，并伴有铀和氧空位电荷补偿。将分析扩展到热处理后的模拟核燃料，发现铬具有混合氧化态，且铬存在不止一种物理形式，这解释了文献中存在的重大差异。这一分析进展的成功证明及其提供的科学依据，为扩大先进二氧化铀燃料中使用的掺杂剂范围创造了机会。
