非能动余热排出系统是核电站堆芯安全性的重要保障，为优化钠冷堆余热排出系统的热工设计方法，明确环境温度及空气冷却器结构变化对余热排出系统的影响。在考虑拔风烟囱自然循环影响的情况下建立完整的钠冷堆非能动传热模型，得到通用的余热排出系统通风量方程，并基于流动平衡和能量平衡对一定设计传热量的余热排出系统进行流程优化并分析环境温度、烟囱高度及翅高变化对系统热力参数的影响规律。结果显示，系统的总驱动压和总传热系数随着环境温度升高逐渐减小，且环境温度对驱动压力的影响更为明显；拔风烟囱高度增加，系统总驱动压和总传热系数均增大，且增大趋势不断变缓，存在设计最优值；翅片管翅片高度减小，系统总传热系数及单位压降传热系数大幅增加，对系统的传热性能影响明显。

The passive residual heat removal system is an important guarantee for the safety of the nuclear power plant. In order to optimize the thermal design method of heat removal system of sodiumcooled reactor,and determine relationships between heat removal system and ambient temperature and structural parameters of air cooler,a complete model of passive heat transfer of sodium-cooled reactor was established considering the influence of natural circulation of the air chimney,and a general equation about airflow was obtained. Meanwhile the passive residual heat removal system with certain thermal load was optimized based on flow balance and energy balance,then the variation law of the intake mass flow,the total driving pressure and the heat transfer coefficient of system was analyzed under different ambient temperature and structural parameters of chimney and finned tubes. The result showed that the total driving pressure and heat transfer coefficient of the system decreased gradually with the increase of ambient temperature,and the influence of the ambient temperature on the driving pressure was more evident. The total driving pressure and the heat transfer coefficient of the system increased with the chimney height,and there was an optimal design because the increasing trend was slowing down. The total heat transfer coefficient and heat transfer coefficient per unit pressure drop of the system increased significantly with the decrease of fin height,which had a significant impact on the heat transfer performance of the system.

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安徽省自然科学基金青年基金（1708085QE122）