CPR1000机组汽动辅助给水泵二级叶轮开裂问题分析

Crack Analysis of the Second-stage Impeller used in the Steam-driven Auxiliary Feed-water Pump of CPR1000 Nuclear Units

本文采用根本原因分析方法,对某核电CPR1000机组辅助给水系统汽动给水泵第二级叶轮开裂的共性问题进行了根本原因的分析。通过化学成分分析、残余应力测试、断口分析,并结合汽动辅助给水泵的三种现场运行工况(全流量、小流量和超速试验)对二级叶轮开展了流-固耦合有限元力学分析,最终确定二级叶轮开裂的根本原因为叶片设计强度不足。并提出相应的改进措施,彻底防止了类似事件的重发。

A root cause analysis was conducted on the crack of the second stage impeller which was used in the steam-driven auxiliary feed-water pump.Through the chemical composition analysis,residual stress analysis and fracture observation and the finite element analysis(FEA)combined with the three different operating modes(rated flow,low flow and over-speed test),the root cause crack was found to be the low design strength of the blade.According to the root cause,some corrective actions were also put forward to prevent the same incident reoccurring.