核电厂稳压器喷淋阀盘根引漏管裂纹成因探究和对策

Crack and Countermeasures of Causes of Pressurizer Spray Valve Packing Leak Pipe in Nuclear Power Plant

某核电集团群厂发生多起稳压器喷淋阀盘根引漏管裂纹故障。通过裂纹管样的金相分析,确认裂纹原因为Cl^(-)导致的应力腐蚀开裂。结合阀门解体检查情况分析得出Cl^(-)来源于盘根轻微渗漏,造成Cl^(-)在引漏管内壁富集。制定了针对性的方案,避免Cl^(-)在引漏管内部富集,进而解决引漏管裂纹故障。

A number of cracks occurred in the lead-in tube of pressurizer spray valve in a nuclear pow-er group plant.Through the metallographic analysis of the crack pipe sample,the cause of the crack was confirmed to be stress corrosion cracking caused by Cl^(-).Based on the analysis of valve disassem-bly inspection,it is concluded that Cl^(-)comes from the slight leakage of the packing root,resulting in Cl^(-)enrichment in the inner wall of the leakage pipe.A specific scheme is developed to avoid Cl^(-) enrichment in the leakage pipe and to solve the leakage pipe crack.