Microstructure, oxidation kinetics and hydrogen absorption of Cr-coated Zr-Sn-Nb alloy cladding tubes after single-sided oxidation at 1000–1200 °C followed by fast reflood

IF 3.2 2区工程技术 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY Journal of Nuclear Materials Pub Date : 2025-02-27 DOI:10.1016/j.jnucmat.2025.155718

Weiwei Xiao , Sheng Xu , Xiao Hu , Jinghao Huang , Shihong Liu , Shuliang Zou

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引用次数: 0

Abstract

Reflood of nuclear fuel assemblies is the top priority accident management strategy for nuclear power plants in the event of a loss of coolant accident, during which the cladding tubes inevitably undergo reflood oxidation. This study aims to investigate the single-sided reflood oxidation behavior of Cr-coated Zr-Sn-Nb alloy cladding tubes at 1000 °C-1200 °C. High-temperature steam oxidation and in-situ quenching were employed to simulate the reflood oxidation process of nuclear fuel assembly cladding tubes in the early stages of severe accidents. The microstructure, cross-sectional layer thickness evolution, oxidation kinetics, and hydrogen absorption of Cr-coated Zr-Sn-Nb alloy cladding tubes during single-sided reflood oxidation process were investigated. The results showed that after single-sided reflood oxidation, microcracks appeared on the surface of the cladding tubes. As the oxidation temperature increases and the oxidation time prolongs, the surface oxidation products gradually evolve from porous flocculent structures to strip-shaped or elliptical bubble structures and worm aggregated structures. A multi-layer layered structure of Cr₂O₃ layer/Cr coating/Cr-Zr diffusion layer/α-Zr(O) was formed on the cross-section of the cladding tube after single-sided reflood oxidation. The thickness of the Cr₂O₃ layer and residual Cr coating does not increase or decrease monotonically with the extension of oxidation time after reflood oxidation at 1200 °C. The kinetics of single-sided reflood oxidation follows a parabolic law, and the oxidation constant increases by about an order of magnitude as the oxidation temperature increases by 100 °C. As the oxidation temperature increases and oxidation time prolongs, the hydrogen absorption of the cladding tube gradually increases. After single-sided reflood oxidation, the hydrides in the Zr-Sn-Nb alloy cladding tube are mainly δ-ZrH_1.5.

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1000 ~ 1200℃快速回流单面氧化后cr包覆Zr-Sn-Nb合金包层管的组织、氧化动力学和吸氢性能

核燃料组件再注是核电站在发生冷却剂损失事故时的首要事故管理策略，在此过程中，包壳管不可避免地会发生再注氧化。本研究旨在研究cr包覆Zr-Sn-Nb合金包覆管在1000℃-1200℃下的单侧再驱氧化行为。采用高温蒸汽氧化法和原位淬火法模拟了严重事故初期核燃料组件包壳管的再淹氧化过程。研究了单面回流氧化过程中cr包覆Zr-Sn-Nb合金包覆管的微观组织、截面厚度演变、氧化动力学和吸氢性能。结果表明：单面回流氧化后，包层管表面出现微裂纹；随着氧化温度的升高和氧化时间的延长，表面氧化产物逐渐由多孔絮状结构演变为条形或椭圆形气泡结构和蠕虫聚集结构。经单侧回流氧化后，熔覆管截面上形成了Cr2O3层/Cr涂层/Cr- zr扩散层/α-Zr(O)的多层结构。在1200℃回流氧化后，随着氧化时间的延长，Cr2O3层厚度和残余Cr涂层厚度没有单调增加或减少的趋势。单侧再驱氧化动力学遵循抛物线规律，氧化常数随氧化温度升高约一个数量级。随着氧化温度的升高和氧化时间的延长，包层管的吸氢量逐渐增大。经单侧回流氧化后，Zr-Sn-Nb合金熔覆管内的氢化物主要为δ-ZrH1.5。

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来源期刊

Journal of Nuclear Materials 工程技术-材料科学：综合

CiteScore

5.70

自引率

25.80%

发文量

601

审稿时长

63 days

期刊介绍： The Journal of Nuclear Materials publishes high quality papers in materials research for nuclear applications, primarily fission reactors, fusion reactors, and similar environments including radiation areas of charged particle accelerators. Both original research and critical review papers covering experimental, theoretical, and computational aspects of either fundamental or applied nature are welcome. The breadth of the field is such that a wide range of processes and properties in the field of materials science and engineering is of interest to the readership, spanning atom-scale processes, microstructures, thermodynamics, mechanical properties, physical properties, and corrosion, for example. Topics covered by JNM Fission reactor materials, including fuels, cladding, core structures, pressure vessels, coolant interactions with materials, moderator and control components, fission product behavior. Materials aspects of the entire fuel cycle. Materials aspects of the actinides and their compounds. Performance of nuclear waste materials; materials aspects of the immobilization of wastes. Fusion reactor materials, including first walls, blankets, insulators and magnets. Neutron and charged particle radiation effects in materials, including defects, transmutations, microstructures, phase changes and macroscopic properties. Interaction of plasmas, ion beams, electron beams and electromagnetic radiation with materials relevant to nuclear systems.