| Title: |
Modeling Defect-Mediated Diffusion in Cr-Doped UO 2 using a Variable-Charge Interatomic Potential |
| Authors: |
Roubille, Théo; Gascoin, Mathieu; Ducher, Roland; Freyss, Michel; Tétot, Robert; Pipon, Yves |
| Contributors: |
Laboratoire d'étude de transfert des radioéléments (ASNR/PSN-RES/SAM/LETR); Service des Accidents Majeurs (ASNR/PSN-RES/SAM); Autorité de Sûreté Nucléaire et de Radioprotection (ASNR)-Autorité de Sûreté Nucléaire et de Radioprotection (ASNR); Institut de recherche sur les systèmes nucléaires pour la production d'énergie bas carbone (CEA - DES) (IRESNE); Commissariat à l'énergie atomique et aux énergies alternatives (CEA); Synthèse, Propriétés et Modélisation des Matériaux - SP2M (ICMMO); Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO); Institut de Chimie - CNRS Chimie (INC-CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie - CNRS Chimie (INC-CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS); Institut de Physique des 2 Infinis de Lyon (IP2I Lyon); Université Claude Bernard Lyon 1 (UCBL); Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS); Autorité de Sûreté nucléaire et de Radioprotection - ASNR (France); ANR-21-CE05-0035,BENEFICIA,Comportement d'un nouveau combustible en cas d'incident ou accident(2021) |
| Source: |
https://asnr.hal.science/hal-05440680 ; 2025. |
| Publisher Information: |
CCSD |
| Publication Year: |
2025 |
| Subject Terms: |
UO 2 DFT SMTB-QB ATF Cr Highlights; UO 2; DFT; SMTB-QB; ATF; Cr Highlights; [PHYS]Physics [physics] |
| Description: |
International audience ; Chromium doping of uranium dioxide is one of the different strategies for the development of Accident Tolerant Fuels (ATFs), promoting a large-grained microstructure that is anticipated to enhance fission gas retention. However, the underlying atomic-scale mechanisms governing this behavior remain incompletely elucidated. This study aims to clarify these mechanisms by systematically investigating defect energetics and diffusion dynamics in Crdoped UO 2 using a semi-empirical tight-binding (SMTB-QB) potential, benchmarked against Density Functional Theory (DFT) calculations. Our approach combines static calculations for defect incorporation and migration energies with high-temperature molecular dynamics simulations to compute atomic diffusion coefficients. Results show that the SMTB-QB model reproduces the stability hierarchy of defects, identifying uranium substitutional sites as energetically favorable. Notably, our calculations reveal that the presence of chromium lowers the uranium migration barrier by approximately 1 eV, resulting in a 1.5-to 2-fold increase in the uranium diffusion coefficient. These findings provide a direct atomistic explanation for the enhanced uranium diffusion that promotes accelerated grain growth, a mechanism acting in concert with proposed liquid phase effects, thereby validating the SMTB-QB potential as a tool to refine multi-faceted fuel performance models. |
| Document Type: |
report |
| Language: |
English |
| DOI: |
10.2139/ssrn.5739006 |
| Availability: |
https://asnr.hal.science/hal-05440680; https://asnr.hal.science/hal-05440680v1/document; https://asnr.hal.science/hal-05440680v1/file/2025_11_05_Article_modeling_Beneficia.pdf; https://doi.org/10.2139/ssrn.5739006 |
| Rights: |
https://creativecommons.org/licenses/by/4.0/ |
| Accession Number: |
edsbas.F593A8A6 |
| Database: |
BASE |