Gascoin Mathieu, Romanova Mariya, Njifon Ibrahim Cheik, Freyss Michel
CEA, DES, IRESNE, DEC, Cadarache, F-13108, Saint-Paul-Lez-Durance, France.
Canadian Nuclear Laboratories, Chalk River Laboratories, Chalk River, ON, Canada.
Commun Chem. 2025 Aug 25;8(1):257. doi: 10.1038/s42004-025-01642-8.
Doping UO with Cr modifies the material's microstructure, enhancing its properties and making Cr-doped UO a promising candidate as accident-tolerant nuclear fuel (ATF). Numerous studies have examined the oxidation state and localization of Cr in UO but often yield inconsistent results, identifying either Cr or Cr as the most stable oxidation state. In the present study, DFT+U is employed to model the incorporation of Cr in the UO matrix, providing insights into the oxidation state of Cr in UO, in relation to the local atomic configurations. In particular, we investigate the O local configuration recently proposed by EPR and XANES experiments, alongside other theoretical configurations. Cr is found to be the most favorable oxidation state in this configuration, agreeing with the most recent experimental data. This work clarifies the controversy over Cr oxidation states and incorporation sites within UO, offering critical data for developing efficient and safer nuclear fuels.
用铬掺杂二氧化铀会改变材料的微观结构，增强其性能，使掺铬二氧化铀成为一种有前途的耐事故核燃料（ATF）候选材料。许多研究都考察了铬在二氧化铀中的氧化态和位置，但结果往往不一致，确定Cr或Cr为最稳定的氧化态。在本研究中，采用DFT+U对铬在二氧化铀基体中的掺入进行建模，以深入了解铬在二氧化铀中的氧化态与局部原子构型的关系。特别是，我们研究了最近由电子顺磁共振（EPR）和X射线吸收近边结构（XANES）实验提出的O局部构型，以及其他理论构型。在这种构型中，发现Cr是最有利的氧化态，这与最新的实验数据一致。这项工作澄清了关于二氧化铀中铬氧化态和掺入位置的争议，为开发高效、安全的核燃料提供了关键数据。
