Vibrations of PWR fuel assembly under axial coolant flow and oblique impingement of jet cross-flow from LOCA holes

IF 1.9 3区工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY

Nuclear Engineering and Design Pub Date : 2024-09-25 DOI:10.1016/j.nucengdes.2024.113586

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引用次数: 0

Abstract

Nuclear fuel bundles are exposed to localized normal impinging jet cross-flow at certain locations along the fuel rod span in a specific design of pressurized water reactors (PWRs) with a fail-safe feature for a loss-of-coolant accident (LOCA). The combined axial flow and jet cross-flow from LOCA holes can induce extensive fuel rod vibration, leading to fretting wear, particularly in rods near the LOCA holes. The dynamics of the fuel assembly depend strongly on the jet impingement angle (

θ

) where the jet flow impinges the fuel rods. This paper investigates experimentally the effect of oblique impingement of a circular jet flow in axial flow on the vibration of a reduced scale model array of the fuel assembly. The mock-up array is tested for three jet inclination angles relative to the rod axis. In addition, the effect of axial flow on the jet-induced dynamics in the array is investigated. The tests are done for the jet centerline located symmetrically or eccentrically relative to the rod inter-column gap. The jet eccentricity is found to have a significant effect on rod bundle stability. The results show that the axial flow has a stabilizing effect on the jet-induced instability. The stability threshold of the array is significantly affected by the jet injection angle. The array becomes significantly more unstable when the jet flow is injected at

θ = 70 °

compared to the normal jet impingement case. For a jet impingement angle larger than 90 degrees, the stability behavior is more complex. While the rod bundle undergoes instability, further increasing the jet velocity did not exacerbate the vibration response, thus suggesting an apparently self-limiting instability for the non-eccentric jet.

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压水堆燃料组件在轴向冷却剂流和 LOCA 孔喷射横流斜撞击下的振动

在压水堆（PWR）的特定设计中，核燃料束在燃料棒跨度的某些位置会受到局部法向冲击射流的横流影响，而压水堆具有针对失冷事故（LOCA）的故障安全功能。来自 LOCA 孔的轴向流和喷射横流会引起燃料棒的剧烈振动，从而导致磨损，尤其是在 LOCA 孔附近的燃料棒。燃料组件的动力学在很大程度上取决于射流撞击燃料棒的射流撞击角 (θ)。本文通过实验研究了轴向流中圆形射流的斜撞击对燃料组件缩比模型阵列振动的影响。测试了模型阵列相对于燃料棒轴线的三个射流倾角。此外，还研究了轴向流对阵列中喷流引起的动力学的影响。测试针对的是喷流中心线相对于杆柱间隙的对称或偏心位置。结果发现，射流偏心率对杆束稳定性有显著影响。结果表明，轴向流对射流引起的不稳定性有稳定作用。阵列的稳定阈值受射流喷射角度的影响很大。与正常的射流撞击情况相比，当射流以 θ=70° 喷射时，阵列的不稳定性明显增加。当射流对撞角大于 90 度时，阵列的稳定性表现更为复杂。虽然杆束发生了不稳定，但进一步提高射流速度并不会加剧振动响应，因此表明非偏心射流具有明显的自限制不稳定性。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Nuclear Engineering and Design 工程技术-核科学技术

CiteScore

3.40

自引率

11.80%

发文量

377

审稿时长

5 months

期刊介绍： Nuclear Engineering and Design covers the wide range of disciplines involved in the engineering, design, safety and construction of nuclear fission reactors. The Editors welcome papers both on applied and innovative aspects and developments in nuclear science and technology. Fundamentals of Reactor Design include: • Thermal-Hydraulics and Core Physics • Safety Analysis, Risk Assessment (PSA) • Structural and Mechanical Engineering • Materials Science • Fuel Behavior and Design • Structural Plant Design • Engineering of Reactor Components • Experiments Aspects beyond fundamentals of Reactor Design covered: • Accident Mitigation Measures • Reactor Control Systems • Licensing Issues • Safeguard Engineering • Economy of Plants • Reprocessing / Waste Disposal • Applications of Nuclear Energy • Maintenance • Decommissioning Papers on new reactor ideas and developments (Generation IV reactors) such as inherently safe modular HTRs, High Performance LWRs/HWRs and LMFBs/GFR will be considered; Actinide Burners, Accelerator Driven Systems, Energy Amplifiers and other special designs of power and research reactors and their applications are also encouraged.