汽辅泵机械超速保护异常动作分析与处理

Analysis and Treatment of Abnormal Action of Mechanical Overspeed Protection of the Steam-driven Auxiliary Feedwater Pump

汽辅泵属于核电厂专设安全设施,大修后的试验成功率高低直接影响机组大修工期。某核电厂汽辅泵在大修后执行机械超速保护试验时,机械超速保护异常动作跳闸4次,影响机组达临界,针对此问题查找出原因并研究对策至关重要。通过对机械超速装置检查,确认机械超速装置异常动作跳闸的根本原因是机械超速装置触发器和脱扣杆的挂钩位置磨损,汽辅泵运行过程中在转速变化、水力干扰和振动干扰的共同作用下机械超速装置松脱跳闸,汽辅泵停运。据此更换触发器和脱扣杆备件并重新执行汽辅泵机械超速试验,同时试验确定机械超速装置触发器和脱扣杆挂钩的磨损标准,彻底消除因汽辅泵机械超速装置触发器和脱扣杆挂钩的磨损标准不明而导致的检修盲区。

The steam-driven auxiliary feedwater pump is a special safety facility of nuclear power plant,and the test success rate after the overhaul directly affects the overhaul period of the unit.During the mechanical overspeed protection test of the steam-driven auxiliary feedwater pump of a nuclear power plant after overhaul,the abnormal action of the mechanical overspeed protection tripped 4 times,affecting the critical state of the unit.It is very important to find out the causes and study countermeasures.Through the inspection of the mechanical overspeed device,it is confirmed that the root cause of the abnormal action and trip of the mechanical overspeed device is the wear of the hook position of the trigger and the trip lever of the mechanical overspeed device.During the operation of the steam-driven auxiliary feedwater pump,under the joint action of the speed change,hydraulic interference and vibration interference,the mechanical overspeed device loosens and trips,and the steam-driven auxiliary feedwater pump stops.As such,the spare parts of the trigger and the trip lever were replaced and the mechanical overspeed test of the steam driven auxiliary feedwater pump was carried out again.At the same time,the wear standard of the trigger and the trip lever hook of the mechanical overspeed device was determined through the test,so as to completely eliminate the blind area of maintenance caused by the unclear wear standard of the trigger and the trip lever hook of the mechanical overspeed device of the steam driven auxiliary feedwater pump.