核反应堆关键焊接结构应力腐蚀裂纹失效评估

以沸水堆堆芯围板焊接热影响区应力腐蚀开裂为例进行了裂纹扩展评估研究.采用有限元模拟与试验检测数据验证相结合的方法对焊接热影响区焊接残余应力场及应力腐蚀开裂扩展过程进行模拟.通过有限元方法计算了应力腐蚀开裂裂纹尖端应力强度因子,再根据应力腐蚀裂纹扩展试验数据获得裂纹尖端应力强度因子与裂纹扩展速率的关系,最终预测了沸水堆堆芯围板的使用寿命,解决了重大构件基于应力腐蚀开裂失效的安全评估问题.该研究过程为重大构件的腐蚀疲劳裂纹失效的安全使用提供了可借鉴的方法.

Life prediction of welded joint in core shroud of BWR due to SCC failure

The life of stress corrosion cracking (SCC) in the welded joint of core shroud in nuclear reactor was predicted.By combining the finite element method (FEM) and experimental results,the residual stress field and subsequent SCC propagation in the heat-affected zone (HAZ) was simulated.The stress intensity factor at the cracking tip was calculated with SCC model, and the relationship between the stress intensity factor and cracking rate from the SCC propagation experiments was used to obtain the propagating rate of the crack.Consequently,the life of core shroud was predicted.This study solved the life prediction of important structures in nuclear reactor due to SCC failure, and also provided an useful method for life prediction of other important engineering structures.