反应流出物蒸汽发生器泄漏原因分析和对策(上)

Cause analysis and countermeasures of reaction effluent steam generator’s leakage (Ⅰ)

某厂1台NS1402材质的反应流出物蒸汽发生器在使用过程中发生泄漏,经分析得出产生泄漏的原因是管孔缝隙处出现了碱液浓缩,引发了NS1402材料的碱应力腐蚀破坏。对蒸汽发生器管孔处出现间隙的原因进行了探讨,发现除氧水产生蒸汽过程中,会引发介质对管束的两相流冲击及过冷沸腾,管束持续振动,导致了管孔处产生间隙。为了解决这个问题,应该同时考虑:控制好管程、壳程介质的平稳工作,采用合理的装置停工流程,设计均匀的给水分配方式,减小折流板间距或考虑采用折流杆等防止管束振动的措施。

A reactor effluent steam generator made of NS1402 leaked during operation. Through analysis, it is concluded that the leakage is caused by alkali concentration at the gap of pipe hole, which leads to alkali stress corrosion damage of NS1402 material. It is found that in the process of generating steam from deoxidized water, the two-phase flow impact and subcooled boiling of the medium on the tube bundle will be caused, and the tube bundle will continue to vibrate, resulting in the gap at the pipe hole. To solve this problem of vibration of the tube bundle, a lot of measures should be taken, such as ensuring the process stable, taking reasonable device shut-down process, designing well-distribute feedwater method, reducing the baffle spacing or adopting rod-baffle for the bundle and so on.