核电站风门掉落事件分析与对策研究

Investigation and Countermeasure Research on Falling Event of Air Dumper in A Nuclear Power Plant

通过对某核电站汽轮机厂房通风系统调节风门掉落事件进行分析,得出事件直接原因是风门铝铆钉连接失效;根本原因是设计缺陷,即风门未设计支撑结构、及铝铆钉与风门主体镀锌铁皮搭配的选材设计不当;加速因素是腐蚀性海洋大气环境条件和现场存在振动的运行工况,对应的老化机理包括大气腐蚀、缝隙腐蚀和应力腐蚀。在对事件深入分析的基础上,提出相应的防护对策建议,包括开展核电站风门预防性普查和实施风门加固、更新铆钉选材消除铆钉电化学腐蚀条件,以及加强风门状态监测等。研究成果对优化在运核电站风门设备管理和新建核电站通风系统设计均具有参考价值。

According to the investigation on the falling event of air dumper of turbine hall ventilation system in a Nuclear Plant, failure of aluminum rivet connection was recognized as the direct cause. And the root cause was design defect, i.e. air dumper structure without support and improper material combination of galvanized iron sheets of the main body of the air dumper and the aluminum rivet. The acceleration failure factors of this event included the corrosive ocean atmosphere and the vibrant operation condition, and the aging mechanisms were atmospheric corrosion crevice corrosion and stress corrosion. Within research in depth, corresponding protective countermeasures were proposed, which included implementing preventive inspection and reinforcement to the air dumper, alteration the rivet＇ s material and carrying out condition monitoring on air dumper, etc. This report would provide reference for the management optimization of air dumper in operating plants and design of ventilation system of plants under construction.