正常余热排出泵汽蚀原因分析

Cause Analysis for Cavitation of RNS Pump

某核电厂半管运行试验,正常余热排出系统流量尚未达到最小设计流量时泵发生汽蚀。研究分析了泵入口管路的三通阻力计算方法,同时通过计算流体力学方法计算了不同缩径比例三通的阻力系数。确认发生汽蚀的主要原因是泵入口管道上的三通内径过小,另外审查已发现三通阻力计算方法选择不合理。采取的措施是更换内径满足要求的三通,并尽可能增大三通内倒角。

During the mid-loop operation test of certain nuclear power plant,pump cavitation happened before the RNS pumps reach the designed minimal flow.The Tee resistance calculation method is reviewed,the resistance of Tee with reduced internal diameter is calculated,the main cause of cavitation is that the ID of Tee is much smaller than the design is confirmed,and unreasonable calculation method is selected.The measures are replacing with Tees with ID meeting requirement and taking large chamfering radius.