小径薄壁管是核电站运行中最容易生成缺陷和发生泄漏的部件和位置。小径薄壁管插接焊缝一般采用射线法进行检测，但是射线检测存在辐射风险，检测区域需要隔离且检测工期较长，并不适于核电站大修期间的大范围应用。通过自然缺陷试块进行小径薄壁管插接焊缝相控阵超声波检测工艺分析及检测能力验证研究。在此基础上，成功将相控阵超声检测技术应用于核电大修现场并发现缺陷。

Trail thin-walled pipes are the most vulnerable parts and locations to defects and leaks in the operation of nuclear power plants. The thin walled pipe seam of the trail was generally inspected by ray method, but the ray detection had some obvious limitations. There is a radiation risk in the detection, the detection area needs to be isolated, and the length of the test period makes it impossible for radiation detection to be used on a large scale during the overhaul of the nuclear power plant. In this paper, based on the natural defect test block, the ultrasonic inspection technology and the test ability of the thin walled tube socket weld phase control array are studied. On the basis of this, practical application of the technology was successfully carried out in the field of nuclear power overhaul and some defects were actually found.