Abstract The analysis of the fluid flow characteristics in reactor pressure vessel is an important part of the hydraulic design of nuclear power plant, which is related to the structure design of reactor internals, the flow distribution at core inlet and the safety of nuclear power plant. The flow distribution and mixing characteristics in the pressurized reactor vessel for the 1000MWe advanced pressurized water reactor is analyzed by using Computational Fluid Dynamics (CFD) method in this study. The geometry model of the full-scaled reactor vessel is built, which includes the cold and hot legs, downcomer, lower plenum, core, upper plenum, top plenum, and is verified with some parameters in DCD. Under normal condition, it is found that the flow skirt, core plate holes and outlet pipe cause pressure loss. The maximum and minimum flow coefficient is 1.028 and 0.961 respectively, and the standard deviation is 0.019. Compared with other reactor type, it shows relatively uniform of the flow distribution at the core inlet. The coolant mixing coefficient is investigated with adding additional variables, showing that mass transfer of coolant occurs near the interface. The coolant mainly distributes in the 90° area of the corresponding core inlet, and mixes at the interface with the coolant from the adjacent cold leg. 0.1% of corresponding coolant is still distributed at the inlet of the outer-ring components, indicating wide range of mixing coefficient distribution.

中文翻译：

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反应堆压力容器内流动分布及混合特性分析

摘要 反应堆压力容器内流体流动特性分析是核电站水力设计的重要组成部分，关系到反应堆内部构件的结构设计、堆芯入口流量分布和核电站的安全。本研究采用计算流体动力学（CFD）方法分析了1000MWe先进压水堆压力反应堆容器内的流动分布和混合特性。建立了全尺寸反应堆容器的几何模型，包括冷、热腿、降液管、下压室、堆芯、上压室、顶压室，并用DCD中的一些参数进行了验证。正常情况下，发现流裙、芯板孔和出水管造成压力损失。最大和最小流量系数分别为1.028和0.961，标准差为0.019。与其他类型的反应器相比，它在堆芯入口处显示出相对均匀的流量分布。通过添加附加变量研究冷却剂混合系数，表明冷却剂的传质发生在界面附近。冷却剂主要分布在相应堆芯入口的 90°区域，并在界面处与相邻冷段的冷却剂混合。0.1%的相应冷却液仍分布在外圈部件入口处，表明混合系数分布范围较广。通过添加附加变量研究冷却剂混合系数，表明冷却剂的传质发生在界面附近。冷却剂主要分布在相应堆芯入口的 90°区域，并在界面处与相邻冷段的冷却剂混合。0.1%的相应冷却液仍分布在外圈部件入口处，表明混合系数分布范围较广。通过添加附加变量研究冷却剂混合系数，表明冷却剂的传质发生在界面附近。冷却剂主要分布在相应堆芯入口的 90°区域，并在界面处与相邻冷段的冷却剂混合。0.1%的相应冷却液仍分布在外圈部件入口处，表明混合系数分布范围较广。