非能动余热排出系统过冷沸腾传热特性研究

Study on Heat Transfer Characteristics of Sub-cooled Boiling in Passive Residual Heat Removal System

小型核电厂非能动余热排出系统(PRS)冷却水过冷沸腾会引起流动不稳定问题,从而影响反应堆安全性。通过静态传热分析,获取流动状态下避免净蒸汽产生的传热管外壁温度限值,并通过提高冷却水出口管出口位置标高和冷却水管内径的方法提高PRS系统冷却水的自然循环流量。研究结果表明,改进方案实施后,冷却水自然循环能力提升,系统排热能力有所提升,可以有效降低冷却水沸腾强度,避免产生过多蒸汽,使PRS系统稳定运行。

The sub-cooled boiling in the passive residual heat removal system(PRS)of miniaturized nuclear power plant can cause unstable flow,which will affect the safety of the reactor.Through static heat transfer analysis,the temperature limit of the outer wall of the heat transfer tube to avoid net steam generation in the flowing state is obtained,and the natural circulating flow of cooling water in PRS system is improved by increasing the outlet position elevation of the cooling water outlet pipe and the inner diameter of the cooling water pipe.The research results show that after the implementation of the improvement scheme,the natural circulation capacity of cooling water and the heat removal capacity of the system are improved,which can effectively reduce the boiling intensity of cooling water,avoid excessive steam generation and make the PRS system run stably.