蒸汽发生器焊接堵管残余应力数值模拟及寿命预测

Numerical Simulation of Residual Stress and Life Prediction of Welding Blocked Pipes of Reactor Steam Generator

对于蒸汽发生器焊接堵管工艺,焊接接头的残余应力为应力腐蚀的发生孕育了环境,而且相比压水堆核电站,第四代先进核反应堆服役温度显著提高,造成更加明显的蠕变现象。采用热弹塑性有限元,基于Nims数据库和ASME标准中提供的数据,对于两种不同焊接结构,计算了使用Incoloy 800H材料的高温端和T22材料的低温端的传热管-堵头环焊的残余应力,并基于线性损伤累积准则,预测了蠕变-疲劳交互作用下焊接堵管的寿命。结果表明,最大残余拉应力点出现在焊缝的根部,开坡口结构的残余应力高于不开坡口结构的残余应力;相较于Nims数据库提供的数据,ASME标准中计算得出的寿命较为保守,开坡口结构的寿命低于不开坡口结构的寿命。

For the welded reactor steam generator,on the one hand,the residual stress of the welded joint provides conditions for stress corrosion;on the other hand,the increase of service temperature in the advanced reactors will cause more obvious creep phenomenon.Based on the data provided in the Nims database and ASME standards,for two different welding structures,this paper calculates the residual stress of heat transfer tube plug circumferential welding at the high temperature end of Incoloy 800H material and the low temperature end of T22 material,and predicts the life of welded pipe plug under the creep fatigue interaction based on the linear damage accumulation criterion.The results show that the point of maximum residual tensile stress occurs at the root of the weld,and the residual stress of the grooved structure is higher than that of the non-grooved structure.Compared with the data provided by the Nims database,the life calculated by the ASME standard is more conservative.The life of the grooved structure is lower than that of the non-grooved structure.