一起主泵变频控制器故障导致的反应堆停堆事故分析

Analysis of a reactor trip event caused by failure of main pump variable frequency controller

通过对某核电厂一起主泵变频控制器故障导致的反应堆停堆事件过程分析,查找控制回路各环节可能出现的问题,确定故障原因为主泵变频器控制器通信板卡金手指存在微动磨损导致控制器通信板卡与背板之间存在间歇性的连接中断,从而触发分闸指令使上游中压断路器跳闸,致使主泵停运和反应堆停堆。通过更换控制器来消除故障,增加对控制器板卡金手指的检查和信号传动试验。

By analyzing the process of the reactor automatic shutdown event triggered by the low flow of the reactor coolant hot leg loop caused by the failure of the main pump variable frequency controller in a nuclear power plant,the possible problems in each link of the control loop were found.It was determined that the cause of the fault was fretting wear of the gold finger of the controller communication board card of the main pump frequency converter,resulting in intermittent connection interruption between the controller communication board card and the backplane,thus triggering the opening command to trip the upstream medium voltage circuit breaker,resulting in the shutdown of the main pump and reactor.The fault was eliminated by replacing the controller,and the inspection of the golden finger of the controller board card and the verification of the signal transmission test were added.