核电厂汽动辅助给水泵叶轮裂纹缺陷成因及改进

Origin and Resolution of Crack Defect in the Impeller of Auxiliary Steam Feed Pump for Nuclear Power Plants

为解决某核电厂汽动辅助给水泵二级叶轮叶片的裂纹缺陷问题,对叶轮结构、受力、断口形貌进行分析,认为裂纹源于叶片尖角应力集中造成的脆性疲劳。采取了对叶片前缘长度、叶片厚度、后盖板厚度加以改进等措施,进行水力性能试验、耐久性试验、小流量试验等,历经876 h的运行、420次的启停,无损检测结果合格。新型二级叶轮满足了设计要求,能够确保核安全设备的可靠运行。

To solve the crack defect of the two-stage impeller blade of the auxiliary steam feed water pump in a nuclear power plant.The structure,force and fracture morphology of the impeller are analyzed,proving that the crack originates from the brittle fatigue caused by the stress concentration in the blade tip.After improving the blade length of the leading edge,the thickness of the blade and the back plate,the hydraulic performance test,the durability test and the small flow test are performed.After 876 h operation and 420 times starting and stopping,the nondestructive test results are qualified.The new twostage impeller meets the design requirements and can ensure the reliable operation of the nuclear safety equipment.