一、前言反应堆主回路工艺管道(简称主管道)是核电站工程核心部分的大动脉,它连接反应堆压力壳、蒸汽发生器和主泵等,成为密闭的环路,使载热体循环流通。主管道长期在高温高压下运行,其安全性、可靠性至关重要,一旦管道破裂,将引起主回路重大失水事故,甚至毁堆。因此,除对主管道材质有严格要求外,对焊接质量的要求也极高。在核电站的腐蚀损坏事故中,管道的应力腐蚀破裂(SCC)占有很大比例。在对 I. Introduction The main circuit of the reactor main process pipeline (referred to as the main pipeline) is the aorta of the core part of a nuclear power station project. It connects the pressure vessel, the steam generator and the main pump of the reactor to become a closed loop that circulates the heating medium. Long-term operation of the main pipeline at high temperature and pressure, its safety, reliability is crucial, once the pipeline rupture, it will lead to a major water loss of the main loop, or even ruined. Therefore, in addition to the strict requirements of the main pipe material, the welding quality requirements are also very high. In nuclear power plant corrosion damage accident, the pipeline stress corrosion cracking (SCC) occupy a large proportion. Right