Abstract In realms of nuclear safety analysis, In-vessel retention (IVR) has been a research focus as it is a promising mitigation strategy for the postulated severe accidents in pressurized water reactors (PWRs). However, the recent development of ocean floating reactors for civil use has greatly motivated the pertinent studies under motion conditions, which can be much different from the known investigations conducted under static condition without the additional acceleration forces induced by motions. Thus, through experimental research, this paper extensively studied the influence of rolling motions on the convection behaviors inside two-layer corium pools, which are the major concerns for IVR research. Transient behaviors of the layered corium pools were obtained, and sensitivity analyses were conducted on three critical parameters, i.e. maximum rolling angle, rolling period and the thickness of metal layer. Experimental results show that the two-layer fluids can stay basically stratified under rolling conditions but mixing phenomena can be observed in the interface nearby region when rolling motions become intense enough. Generally, rolling motions can weaken the thermal stratification inside the layered corium pool, and enhance heat removal capacity from the corium pool to the outside cooling boundary. These phenomena indicate a good chance for the efficient decay heat removal from the corium pool under rolling motions. This study is supposed to provide valuable references to assess the success probability of IVR design applied in reactors operated under ocean conditions.

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滚动运动对两层真皮池内对流行为影响的实验研究

摘要 在核安全分析领域，容器内滞留 (IVR) 一直是研究热点，因为它是压水反应堆 (PWR) 假定严重事故的一种有前景的缓解策略。然而，民用海洋浮式反应堆的最新发展极大地推动了运动条件下的相关研究，这与在没有运动引起的额外加速力的静态条件下进行的已知研究大不相同。因此，通过实验研究，本文广泛研究了滚动运动对两层真皮池内对流行为的影响，这是 IVR 研究的主要关注点。获得了层状真皮池的瞬态行为，并对三个关键参数进行了敏感性分析，即 最大轧制角度、轧制周期和金属层厚度。实验结果表明，两层流体在滚动条件下可以保持基本分层，但当滚动运动足够强烈时，在界面附近区域可以观察到混合现象。通常，滚动运动可以减弱层状真皮池内部的热分层，并增强从真皮池到外部冷却边界的散热能力。这些现象表明在滚动运动下从真皮池中有效去除衰变热的好机会。该研究旨在为评估IVR设计应用于海洋条件下运行的反应堆的成功概率提供有价值的参考。实验结果表明，两层流体在滚动条件下可以保持基本分层，但当滚动运动足够强烈时，在界面附近区域可以观察到混合现象。通常，滚动运动可以减弱层状真皮池内部的热分层，增强从真皮池到外部冷却边界的散热能力。这些现象表明在滚动运动下从真皮池中有效去除衰变热的好机会。该研究旨在为评估IVR设计应用于海洋条件下运行的反应堆的成功概率提供有价值的参考。实验结果表明，两层流体在滚动条件下可以保持基本分层，但当滚动运动足够强烈时，在界面附近区域可以观察到混合现象。通常，滚动运动可以减弱层状真皮池内部的热分层，增强从真皮池到外部冷却边界的散热能力。这些现象表明在滚动运动下从真皮池中有效去除衰变热的好机会。该研究旨在为评估IVR设计应用于海洋条件下运行的反应堆的成功概率提供有价值的参考。通常，滚动运动可以减弱层状真皮池内部的热分层，增强从真皮池到外部冷却边界的散热能力。这些现象表明在滚动运动下从真皮池中有效去除衰变热的好机会。该研究旨在为评估IVR设计应用于海洋条件下运行的反应堆的成功概率提供有价值的参考。通常，滚动运动可以减弱层状真皮池内部的热分层，增强从真皮池到外部冷却边界的散热能力。这些现象表明在滚动运动下从真皮池中有效去除衰变热的好机会。该研究旨在为评估IVR设计应用于海洋条件下运行的反应堆的成功概率提供有价值的参考。