在役AP1000主泵锁紧杯断裂故障原因分析

三门核电厂2号机组首循环连续运行期间，发生了大型屏蔽电机主泵故障事件，导致机组停运。为分析主泵故障发生的原因，基于故障特点和原因分析方法论，制定了主泵故障排查的根本原因分析方法；通过排查主泵制造记录、评估现场运行数据、拆检取证、设计分析与试验验证、根本原因分析评估，最终确认主泵故障原因是下推力盘锁紧杯受周围流场流体激励作用发生局部共振，初始缺陷在共振作用下持续扩展并最终导致锁紧杯断裂，进而磨穿主泵屏蔽套并导致主泵故障。本研究建立的根本原因分析方法可为同类问题的原因分析和问题处理提供参考。 

Root Cause Analysis of In-Situ AP1000 Reactor Coolant Pump Lock Cup Failure

The failure of the large-scale canned motor reactor coolant pump (RCP) of Sanmen Unit 2 caused the unit to shut down in the first cycle of operation. In order to analyze the causes of the RCP fault, based on the fault characteristics and cause analysis methodology, this paper develops the RCP fault root cause analysis method. Through the RCP manufacturing record investigation, on-site operation data evaluation, disassembly and inspection forensics analysis, design analysis and test verification, root cause analysis and evaluation, the root cause of the RCP failure is confirmed that the lower thrust runner lock cup is affected by the resonance flow induced vibration. The initial flaw continues to expand under the action of the resonance and eventually separates. The lock cup fragment makes two holes on the stator can and eventually leads to the RCP failure. The root cause analysis method established in this study can be used for the analysis and treatment of similar complex problems.