压水堆上腔室流场的实验研究

THE EXPERIMENTAL STUDY ON STEADY FLOW IN PWR UPPER PLENUM

ＰＷＲ作为核电发展的主要堆型，在全世界范围内得到了广泛的应用，也是我国的主要发展堆型。但是对关系到反应堆安全运行的、直接作用在控制棒导向筒上的上腔室流场的分析研究，长期以来由于紊流流动机制的复杂性和上腔室中控制棒导向筒组件布置的密集性，这方面的研究一直没有深入下去。在压水堆运行期间，作用在上腔室构件上的作用力与冷却剂的流动特性有很大的关系，通过模拟实验弄清上腔室的流速分布，对了解作用在控制棒上的水力载荷，以及控制棒能否按指令在导向筒内自由升降和快速下插具有十分重要的意义。本文在３００ＭＷｅ核电站ＰＷＲ上腔室１：４可视化模拟体中，以水为介质进行了上腔室流场的可视化实验研究。采用激光多普勒测速仪（ＬＤＶ）和Ｎ－Ｊ型应变片式测速仪测得了上腔室模拟体中的流速，并用归一化的数据处理方法，显示了整个流场的流速分布规律，找出了整个流速的最大区和最大值。从而为控制棒导向筒的结构力学分析和ＰＷＲ上腔室的数值模拟分析提供实验依据。

As a prototypal reactor of nuclear power development,PWR is widely applied all over the world and will be mainly developed in our country.Because of complication in turbulent flow and concentration of the control rod guide tubes and bundles in the plenum,the research on the flow,which relates to the nuclear reactor safety and directly acts on the tubes and bundles, has not been fully carried out for a long time. During the operation of a PWR,the force,acting on the components in the plenum,is largely determined by the flow characteristic of the coolant. Therefore it is necessary to clarify velocity distribution in the plenum by simulation method for understanding the hydraulic load on the tubes and bundles and whether or not the control rods moving upward and downward freely and droping rapidly in emergency case by order.This paper presents experiments of steady flow in PWR upper plenum.By visual method the experiments are carried out in a 1/4 scale transparent model of the upper plenum of a 300 MWe PWR. Water is chosen as the fluid.Stream pattern of the flow field is displayed. The velocity distributions are obtained by using Laser Doppler Velocity meter and N-J type dynamic resistance stressed film flow-velocity measuring meter.The maximum velocity point and area are derived by normalized processing of experimental data.It will provide the structure-mechanical study on control rod tubes and numerical analysis of the flow in PWR upper plenum with experimental basis.