反应堆安全壳高精度气溶胶自然沉积模型的开发及验证  

Development and validation of high-precision aerosol models for natural deposition processes in reactor containment

作　　者：李济深 张斌 高鹏程 缪凡 单建强 LI Jishen;ZHANG Bin;GAO Pengcheng;MIAO Fan;SHAN Jianqiang(School of Nuclear Science and Technology,Xi'an Jiaotong University,Xi'an 710049,China;State Key Laboratory of Multiphase Flow in Power Engineering,Xi'an Jiaotong University,Xi'an 710049,China)

机构地区：[1]西安交通大学核科学与技术学院,西安710049 [2]西安交通大学动力工程多相流国家重点实验室,西安710049

出　　处：《核技术》2023年第5期114-126,共13页Nuclear Techniques

基　　金：国家重点研发计划(No.2019YFE0191600)资助。

摘　　要：在压水堆严重事故过程中,气溶胶作为裂变产物的主要载体在安全壳内悬浮,有泄漏到外部环境中造成放射性污染的潜在威胁。安全壳气相悬浮的气溶胶会通过自然沉积机理沉降到壁面或地坑水,降低大气放射性。针对ISAA程序气溶胶模型精度不足的问题,改进安全壳气溶胶自然沉积模型。通过引入气溶胶动态形状因子,修正非球形气溶胶自然沉积速率,改进了重力沉积、布朗扩散、热泳和扩散泳沉积模型。选取AHMED(Aerosol and Heat Transfer Measurement Device)、ABCOVE(Aerosol Behavior Code Validation and Evaluation)和LACE(Light Water Reactor Aerosoal Containment Experiments)实验对改进代码进行评估。结果表明:改进模型能够更加精确模拟气溶胶质量峰值,响应安全壳压力温度对气溶胶自然沉积速率的影响,显著地提高了安全壳气溶胶残留质量的计算精度。改进后ISAA程序性能可以满足分析先进压水堆严重事故安全壳内气溶胶自然沉积行为的需要。[Backgroud]Nuclear safety is the lifeline for the development and application of nuclear energy.In severe accidents of pressurized water reactor(PWR),aerosols,as the main carrier of fission products,are suspended in the containment vessel,posing a potential threat of radioactive contamination caused by leakage into the environment.The gas-phase aerosols suspended in the containment will settle to the wall or sump water through the natural deposition mechanism,thereby reducing atmospheric radioactivity.[Purpose]This study aims to improve the low accuracy of the aerosol model in the ISAA code by developing high-precision natural deposition model of aerosol in the containment.[Methods]Firstly,the aerosol dynamic shape factor was introduced to correct the natural deposition rate of non-spherical aerosols.Then,the gravity,Brownian diffusion,thermophoresis and diffusiophoresis deposition models were improved respectively.Finally,AHMED(Aerosol and Heat Transfer Measurement Device),ABCOVE(Aerosol Behavior Code Validation and Evaluation)and LACE(Light Water Reactor Aerosoal Containment Experiments)experiments were employed to validate and evaluate the improved ISAA code.[Results]Calculation results show that the improved model is applicable to more accurate simulation of the peak aerosol mass and responding to the influence of the containment pressure and temperature on the natural deposition rate of aerosols,and the calculation accuracy of the residual mass of aerosols in the containment is significantly improved simultaneously.[Conclusions]The performance of improved ISAA with high-precision aerosol models of this study meets the requirements for analyzing the natural deposition behavior of aerosol in containment of advanced PWRs in severe accident.In the future,further optimization will be made to address the problems found in the current aerosol model.

关 键 词：气溶胶 核安全 严重事故 自然沉积模型 ISAA 

分 类 号：TL364[核科学技术—核技术及应用]