核电厂海水循环水系统金属膨胀节失效分析

Failure Analysis of Metal Expansion Joint in Seawater Circulating Water System of Nuclear Power Plant

本文介绍了某核电厂海水循环水系统金属波纹管膨胀节腐蚀的现象,并对腐蚀原因进行分析,得出腐蚀的主要原因是由于金属波纹管特殊的成型方法,导致其耐海水性能不良;波纹管与法兰连接的环焊缝处存在的缺陷在交变应力的作用下被腐蚀,且腐蚀面逐渐恶化。通过本文的原因分析,最终对膨胀节整体选型更改为整体密封面、缠绕式结构的橡胶膨胀节提出合理化建议,为后续核电厂防腐管理和海工设备选型提供参考。

This paper introduces the corrosion phenomenon of metal bellows expansion joint in seawater circulating water system of a nuclear power plant, and analyzes the causes of corrosion. It is concluded that the main cause of corrosion is due to the special forming method of metal bellows,which leads to its poor seawater resistance;The defects in the circumferential weld of bellows and flange connection are corroded under the action of alternating stress, and the corrosion surface gradually deteriorates. Based on the analysis of the reasons in this paper, reasonable suggestions are put forward to change the overall type selection of expansion joint to the rubber expansion joint with integral sealing surface and winding structure, which can provide reference for the follow-up anti-corrosion management of nuclear power plant and the selection of marine equipment.