交变热应力对疏水管焊缝反复开裂的影响  

Effect of Alternating Thermal Stress on Repeated Cracking of Drain Pipe Weld

作　　者：张藤飞 李喆 吕涛 陈小萌 ZHANG Teng-fei;LI Zhe;LV Tao;CHEN Xiao-meng(Jiangsu Nuclear Power Corporation;School of Energy and Power Engineering,Xi’an Jiaotong University)

机构地区：[1]江苏核电有限公司 [2]西安交通大学能源与动力工程学院

出　　处：《化工机械》2023年第6期869-874,共6页Chemical Engineering & Machinery

摘　　要：针对田湾3、4号机组MAL系统蒸汽疏水管道在机组运行中多次发生疏水阀下游管道焊缝开裂的情况,结合数值模拟对下游管路焊缝开裂失效原因和内在机理进行研究。结果表明,疏水器或气动疏水阀的频繁开启和关闭引起的管道交变热应力是造成焊缝异常开裂的主要原因,且温差和交变热应力随下游疏水管阻力的增大而增大。增大下游疏水管管径、减少管道流动阻力、提高疏水排放位置压力、选择与管路疏水量匹配且连续排水的疏水器以及节流能力更强的旁路疏水阀可减少疏水管交变热应力,提高疏水管道系统的运行可靠性。Considering the fact that steam trap line in the MAL system of Tianwan Units 3 and 4 repeatedly suffered weld cracks on the downstream tee or elbow of the trap under normal operating conditions and through combined with numerical simulation,both the causes and internal mechanism of weld cracking failure in downstream pipeline were studied.The results show that,the alternating thermal stress of the pipeline caused by the frequent opening and closing of the trap or pneumatic trap becomes the main reason of the abnormal weld cracking,and the temperature difference and the alternating thermal stress increase with the rising of the resistance of the downstream trap.Through increasing diameter of the downstream trap,reducing flow resistance of the pipeline,increasing pressure of the trap discharge position and selecting the trap that matches the drain amount of the pipeline and drains continuously,the bypass trap with stronger throttling ability can reduce the alternating thermal stress of the trap and improve the operation reliability of the trap system.

关 键 词：核电站 交变热应力 焊缝开裂 疏水不畅 

分 类 号：TM623[电气工程—电力系统及自动化]