EPR核电厂CRDM耐压壳焊缝缺陷信号分析

Defects Analysis of CRDM Weld in EPR Nuclear Power Plants

核电厂控制棒驱动机构(CRDM)长期处于高温、高压和高辐射环境中,其耐压壳异种金属焊缝容易出现裂纹等缺陷,是大修期间在役检查的关注重点。针对该焊缝役前超声检查中发现的疑似缺陷显示,通过补充目视、射线、超声相控阵和破坏性试验,验证了此类显示信号为不完全再结晶的奥氏体硬化晶粒造成的冶金显示,不影响耐压壳焊缝的质量,并总结了核电厂核岛设备超声疑似缺陷信号分析验证的方法。

The control rod drive mechanism(CRDM)pressure housing in nuclear power plants is subjected to high temperature,high pressure and high radiation.The pressure housing welds is prone to crack defects,which is the focus of the in-service inspection during the overhaul.In view of the suspected defects found by Ultrasonic inspection in the pre-service inspection,supplement nondestructive test and destructive test were implemented.The results proved that the indications were metallurgical indications caused by the austenitic hardened grain with incomplete recrystallization,which is without effect on the quality of the welds.The methods of signal analysis for suspected defects were summarized.