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DOE OSTI · 3001374

Diffusion behavior of lanthanide fission products in bcc Fe cladding: A first-principles study

Ke, Jia-Hong [Idaho National Laboratory (INL), Idaho Falls, ID (United States)] (ORCID:0000000289317885)·Song, Rongjie [Idaho National Laboratory (INL), Idaho Falls, ID (United States)] (ORCID:0009000790378654)
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Abstract

Fuel-cladding chemical interaction poses significant challenges in nuclear reactors, where fission products generated from nuclear fuel interact with Fe-based cladding materials, potentially compromising their structural integrity. This study investigates the diffusion behavior of lanthanide fission products, Lanthanum (La), Cerium (Ce), Praseodymium (Pr), and Neodymium (Nd), within body-centered cubic (bcc) Fe cladding using the density functional theory, nudged elastic band method, and self-consistent mean field theory. Our results reveal significant vacancy binding energies, particularly with the 1st and 2nd nearest neighbors, which diminish beyond the 5th nearest neighbor, with La exhibiting the strongest binding affinity, followed by Nd, Ce, and Pr. The nudged elastic band calculations indicate significant high barriers for the dissociation of 1st nearest neighbor vacancy-solute pairs for all fission products. The tracer diffusion coefficients of these fission products were derived in an Arrhenius form, with a magnetic correction that accounts for the high-temperature paramagnetic state. The significant trapping effect of vacancies caused by a very dilute concentration of fission products reduces vacancy mobility, potentially leading to modifications in point defect supersaturation, void nucleation, and swelling under irradiation. These represent critical challenges for irradiated cladding materials. The tracer diffusion coefficients indicate that Nd diffuses the fastest, followed by La, Ce, and Pr. Furthermore, this study provides essential insights for understanding fission product transport in cladding materials and informs future design strategies to mitigate fuel-cladding chemical interaction, ultimately enhancing nuclear reactor safety and performance.

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Diffusiondensity functional theoryfission productsfuel claddingvacancy mobility

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Ke, Jia-Hong [Idaho National Laboratory (INL), Idaho Falls, ID (United States)] (ORCID:0000000289317885), Song, Rongjie [Idaho National Laboratory (INL), Idaho Falls, ID (United States)] (ORCID:0009000790378654). 2025-07-13. Diffusion behavior of lanthanide fission products in bcc Fe cladding: A first-principles study. https://doi.org/10.1016/j.commatsci.2025.114071

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