水下焊接技术在核电站建设中的应用与研究展望

Application and research prospect of underwater welding technology in nuclear power plant construction

目前,核电站的焊修工作都是由行车焊工进行,质量难以保证,水下局部干焊技术是目前的发展趋势。文中首先分析了水下焊接技术在核电站焊接修复中的应用现状,并以局部干法水下焊接304奥氏体不锈钢对接焊缝为例,指出了水下焊接接头与空气中焊接接头力学性能和耐蚀性的差距。为了适应未来高放射性、高风险的水下焊接环境,研制局部干式水下焊接自动化系统将是未来核电站关键敏感部件水下焊接修复的关键。为此,在此基础上,研制了一套遥控水下局部干式金属惰性气体保护焊自动焊接系统,其关键部件是一个能模拟30 m水深环境的压力容器。焊接舱内有3个摄像头,其可以监控设备的运行状态和焊接过程。304奥氏体不锈钢15 m水深焊接试验结果表明,该系统能满足局部干焊试验的要求。这些研究成果对核电站水下焊接修复技术的发展具有重要意义。

At present,the welding repair work of nuclear power station was carried out by crane welder,and the quality was difficult to guarantee.Underwater local dry welding technology was the current development trend.The application status of underwater welding technology in nuclear power plant welding repair was analyzed in this paper.The local dry underwater welding of 304 austenitic stainless steel butt weld was taken as an example.The difference of mechanical properties and corrosion resistance between underwater welded joint and air welded joint was pointed out.In order to adapt to the future underwater welding environment with high radioactivity and high risk,the development of local dry underwater welding automation system would be the key to underwater welding repair of key sensitive components of nuclear power plant in the future.Therefore,a set of remote control underwater local dry metal inert gas welding automatic welding system was developed on this basis.Its key component was a pressure vessel which could simulate the water depth of 30 m.There were three cameras in the welding cabin,which could monitor the operation status of the equipment and the welding process.The welding test results of 304 austenitic stainless steel in15 m water depth showed that the system could meet the requirements of local dry welding test.These research results were of great significance to the development of underwater welding repair technology for nuclear power plant.