备用状态下核电厂重要厂用海水系统泵腔积气机理及解决方案

针对某北方核电厂重要厂用海水系统的备用海水泵,冬季因泵腔积气无法启动的现象,开展了静态条件下低温海水受环境加热升温析气动态特性、泵腔区域析气特征、排气系统缺陷分析、泵腔积气机理研究,在此基础上,提出了海水泵排气系统改造方案。结果表明:环境温度、海水的初始温度对海水中溶解氧动态析出特性有重要影响、盐度对海水中溶解氧动态析出特性影响不大;由于重要厂用海水系统的布局及海水泵运行特点,使得在冬季海水泵较长的备用期间,可以析出大量的溶解气体;在带有较长近水平布置的排气管道影响下,由于析气无法排放,可在备用海水泵腔体区域形成积气空间;排气系统的改进方案,在几台机组上得到成功实施,解决了备用海水泵冬季积气无法启动的问题。

Research on gaseous accumulation in chamber of pump in stand-by mode and the methods to solve these problems

The phenomenon of seawater pump’s failure to restart,which is caused by gaseous accumulation in the chamber of pump in winter during stand-by mode,were studied.These researches include the gaseous release characteristics of seawater which is heated by warm circumstances, gaseous release characteristics in the region of chamber of seawater pump,the defects of original designed exhaust gas pipe,mechanism of gaseous accumulation in the chamber of pump,and the transform method to solve the problem of failure to restart.Results show that the release rate of oxygen from seawater under standard atmosphere was enhanced by the higher environmental temperature and the lower initial temperature of water,while seawater salinity has slightly effect on the characteristics of gaseous release.A large quantity of gaseous could be released during winter time as the arrangement of essential service water system and the seawater pump’s operation characteristic during stand-by mode.The released gas could be accumulated in the pump’s chamber which has long near horizontal arranged pipe in its exhaust gas pipe system.Under these studies,a transform program was designed and implemented,which have shown successful results.