Interaction of lanthanum oxide and molten fluoride system FLiNaK: In situ Raman experiment and density functional theory simulations

IF 2 3区化学 Q4 CHEMISTRY, PHYSICAL

Chemical Physics Pub Date : 2025-02-12 DOI:10.1016/j.chemphys.2025.112659

Irina Zakiryanova, Dmitry Zakiryanov

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Abstract

Molten mixture of alkali metal fluorides FLiNaK is a promising coolant for molten salt nuclear reactors. The presence of oxygen-containing impurities can lead to corrosion, degradation and destruction of structural materials. This paper presents the results of studying the mechanism of the interaction of the molten FLiNaK with lanthanum oxide by in situ Raman spectroscopy and ab initio molecular dynamics (AIMD) simulations. High-temperature Raman studies supplemented by the results of XRD analysis and thermodynamic modeling reveal an irreversible heterogeneous reaction La₂O₃(s) + 2 LiF(sol) → 2 LaOF(s) + Li₂O(sol). When the temperature increases, the LaOF dissolves. Additionally, the kinetics of interaction of La₂O₃ with water vapor in the air atmosphere was studied. AIMD data concur closely with the experimental results: we identified formation of the intermediate range order structures containing oxygen, lanthanum, lithium and fluorine ions with the OLi coordination number being 1.92.

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来源期刊

Chemical Physics 化学-物理：原子、分子和化学物理

CiteScore

4.60

自引率

4.30%

发文量

278

审稿时长

39 days

期刊介绍： Chemical Physics publishes experimental and theoretical papers on all aspects of chemical physics. In this journal, experiments are related to theory, and in turn theoretical papers are related to present or future experiments. Subjects covered include: spectroscopy and molecular structure, interacting systems, relaxation phenomena, biological systems, materials, fundamental problems in molecular reactivity, molecular quantum theory and statistical mechanics. Computational chemistry studies of routine character are not appropriate for this journal.