液体燃料熔盐堆是第四代先进核能系统的候选堆型之一,应急排盐冷却系统是其可设置的特殊安全设计。本文以熔盐实验堆(Molten Salt Reactor Experiment,MSRE)应急排盐冷却系统为研究对象,探究换热元件内层屏障破损对其正常余热导出功能...液体燃料熔盐堆是第四代先进核能系统的候选堆型之一,应急排盐冷却系统是其可设置的特殊安全设计。本文以熔盐实验堆(Molten Salt Reactor Experiment,MSRE)应急排盐冷却系统为研究对象,探究换热元件内层屏障破损对其正常余热导出功能的影响。该研究基于计算流体动力学(Computational Fluid Dynamics,CFD)模拟方法,通过构建传热和多相流动模型分析破损后的传热和流动现象,并对关键影响参数进行敏感性分析。结果表明,内层套管破损后,18.4%的冷却水从破损位置经气隙层流出,单根换热元件功率提升到29.434 kW,破损位置附近外层套管出现局部温度低点。敏感性分析结果表明,破损尺寸、破损位置和气隙层压力变化均会对换热元件传热产生明显影响,其中传热对破损尺寸的敏感性最强。该分析结果可以为熔盐堆应急排盐冷却系统工程设计提供研究数据。展开更多
Fuel-coolant interaction(FCI)remains one of the most complex challenges in severe accident research,with the triggering process being a key aspect that may govern subsequent fine fragmentation and potential steam expl...Fuel-coolant interaction(FCI)remains one of the most complex challenges in severe accident research,with the triggering process being a key aspect that may govern subsequent fine fragmentation and potential steam explosions.In this study,the evolution characteristics of droplet-water interactions under external disturbance conditions were investigated using a self-designed FCI experimental setup.The experimental observations revealed that cavity formation reduced the drag force on the droplet,thereby increasing its peak velocity.However,the external disturbance pressure can disrupt the cavity,leading to a reduction in the droplet peak velocity.Furthermore,it was found that an increase in external disturbance pressure tended to increase the peak value of the droplet expansion rate,thereby promoting the fine-fragmentation process.This effect holds regardless of the initial droplet temperature,coolant temperature,or even when using droplet materials such as lead,which is generally considered unfavorable for steam explosions.Comparative analyses indicated that a higher external disturbance pressure may shorten the triggering time of the droplet surface and enhance the trigger intensity.These findings provide important phenomenological insights for further investigation of the triggering mechanisms in the initial stage of fuel-coolant interactions.展开更多
基金supported by the operating fund of Key Laboratory of Nuclear Power Systems and Equipment(Shanghai Jiao Tong University),Ministry of Education,China,the Natural Science Foundation of Shanghai Municipality(25ZR1402177)the National Natural Science Foundation of China(12105167)。
文摘Fuel-coolant interaction(FCI)remains one of the most complex challenges in severe accident research,with the triggering process being a key aspect that may govern subsequent fine fragmentation and potential steam explosions.In this study,the evolution characteristics of droplet-water interactions under external disturbance conditions were investigated using a self-designed FCI experimental setup.The experimental observations revealed that cavity formation reduced the drag force on the droplet,thereby increasing its peak velocity.However,the external disturbance pressure can disrupt the cavity,leading to a reduction in the droplet peak velocity.Furthermore,it was found that an increase in external disturbance pressure tended to increase the peak value of the droplet expansion rate,thereby promoting the fine-fragmentation process.This effect holds regardless of the initial droplet temperature,coolant temperature,or even when using droplet materials such as lead,which is generally considered unfavorable for steam explosions.Comparative analyses indicated that a higher external disturbance pressure may shorten the triggering time of the droplet surface and enhance the trigger intensity.These findings provide important phenomenological insights for further investigation of the triggering mechanisms in the initial stage of fuel-coolant interactions.
