核级接线箱DBA试验后螺栓断裂原因分析及处理OA

Based on the analysis of fracture morphology and the detection of corrosion residue,the failure reason of the bolt in a junction box after Design Basis Accident(DBA)test was analyzed.It was determined that the fracture mode of the bolt was intergranular brittle fracture,and the main reason for the fracture was the intergranular corrosion caused by the spray liquid of DBA test under high temperature and high pressure environment.According to the root cause of the failure,the design improvement scheme of the junction box is formulated,and an economic and effective supplementary qualification method is put forward.The practice shows that the design improvement can effectively eliminate the performance defects of the junction box,while the supplementary qualification provides evidence for the applicability of the junction box in harsh en-vironment and facilitates reasonable control of qualification costs.