铅铋冷却燃料棒束堵流事故CFD模拟与分析

CFD Simulation and Analysis of Blockage Accident in a Lead-Bismuth Eutectic Cooled Fuel Rod Bundle

【目的】铅铋冷却快堆(LFR)具备固有安全性、较高的能量密度和较长的燃料循环寿期等特点,是第四代核反应堆研究的重点堆型。LFR在运行过程中产生的腐蚀产物可能会引起堵流事故,对反应堆安全造成威胁。【方法】通过计算流体力学软件Fluent,对含绕丝19棒束燃料组件建模,模拟分析了正常工况和多组堵流工况下的铅铋工质流动传热特性,并和Pacio实验进行了对比。【结果】获得了不同工况下包壳表面最高温度分布、堵块周围速度分布和瞬时涡场结构,分析了堵块参数对流场分布和传热的影响规律。【意义】结果可为分析LFR堵流事故的发展和影响提供参考。

[Background] Lead-bismuth eutectic cooled fast reactor(LFR) is becoming increasingly recognized among all the fourth-generation nuclear reactors because of its inherent safety, high power density,and long-life fuel cycle. Corrosion products generated during the operation of LFR may cause flow blockage accidents and threaten the safety of the reactor.[Methods]Using the computational fluid dynamics software Fluent, this study established a theoretical model for a 19-rod bundle fuel assembly with wrapped wire,which was then verified by the Pacio experiment. The model was used to investigate the flow and heat transfer characteristics of the lead-bismuth eutectic working fluid under both normal conditions and multiple groups of flow blockage conditions.[Results]Results obtained the maximum temperature distribution on the cladding surface, the velocity distribution around the block, and the instantaneous vortex field structure under different working conditions. Finally, influences of the block parameters on the flow field distribution and heat transport were concluded.[Conclusions]This work can provide a reference for analyzing the development and impact of LFR blockage accidents.