Abstract The difference in the amount of molten corium and outlet diameter influences the corium spreading, which is essential to enhance the safety of nuclear power plants. To investigate this phenomenon, in this work, the influence of the scale relation between the amount of molten metal and the outlet diameter (L/D) on the corium spreading was investigated. Experiments involving the spreading of a molten corium simulant on a stainless-steel plate were performed under various nozzle sizes and sample amounts. The spreading behavior during the experiment was recorded via a video camera. Based on the obtained experimental data, a dimensionless analysis was performed to determine the dominant parameters responsible for the spreading phenomena, and spreading models were developed to infer the solidified area and thickness. The results indicated that the spreading mode may vary at approximately L/D = 6, owing to the change in the force balance represented by the Weber and Reynolds numbers. The developed spreading model considering both the length and thickness values can help understand and predict the spreading of the fuel debris in the first floor.

中文翻译：

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熔融真皮量和出口直径对真皮铺展的尺度效应

摘要 熔化的钄量和出口直径的差异会影响钄的扩散，这对提高核电站的安全性至关重要。为了研究这种现象，在这项工作中，研究了熔融金属量和出口直径 (L/D) 之间的比例关系对钴合金扩散的影响。在不同的喷嘴尺寸和样品量下进行了涉及在不锈钢板上散布熔融钴模拟物的实验。实验过程中的传播行为通过摄像机记录。基于获得的实验数据，进行了无量纲分析以确定导致扩散现象的主要参数，并开发了扩散模型来推断凝固面积和厚度。结果表明，由于韦伯数和雷诺数所代表的力平衡的变化，传播模式可能在大约 L/D = 6 处发生变化。开发的同时考虑长度和厚度值的扩散模型可以帮助理解和预测燃料碎片在一层的扩散。