基于准可逆方法的封闭空间放射性气溶胶溯源研究

辐射防护 ›› 2024, Vol. 44 ›› Issue (S1): 18-23.

基于准可逆方法的封闭空间放射性气溶胶溯源研究

张明昊¹, 吴荣俊², 陈艳², 倪木一¹, 蒋应伍¹, 王雨晴¹

1.中山大学中法核工程与技术学院,广东珠海 519082;
2.中国船舶重工集团公司第七一九研究所,武汉 430064

收稿日期:2023-11-23 出版日期:2024-11-20 发布日期:2024-12-26
作者简介:张明昊(1999—),男,2021年6月毕业于东华理工大学,2024年6月毕业于中山大学,获硕士学位,初级工程师。E-mail:zhangmh68@mail2.sysu.edu.cn

Study on traceability of radioactive aerosols in closed spaces based on quasi reversible method

ZHANG Minghao¹, WU Rongjun², CHEN Yan², NI Muyi¹, JIANG Yingwu¹, WANG Yuqing¹

1. Institute of nuclear engineering and technology, Sun Yat-sen University, Guangdong Zhuhai 519082;
2. The 719 Institute of China State Shipbuilding Corporation Co. Ltd., Hubei Wuhan 430064

Received:2023-11-23 Online:2024-11-20 Published:2024-12-26

摘要/Abstract

摘要： 准确、快速地定位核设施内放射性源项的泄漏点对于确保相关运营维修技术人员的安全至关重要,核设施出现少量放射性泄露后,一般难以直接观察到源项的释放点。而利用场内的辐射监测数据,结合可逆的扩散模型反演计算,可间接获取源项位置信息。本文基于准可逆方法,考虑气溶胶颗粒重力沉降、布朗扩散等因素,结合Cunningham滑移修正颗粒所受阻力,开展封闭空间内放射性源项在对流扩散环境中的直接反演模拟研究。本文考虑了典型放射性气溶胶动力学参数,结合湍流场中的颗粒涡流扩散率,建立了颗粒污染物扩散的k-epsilon湍流方程和对流扩散方程。然后,通过时间步长的强制反转,并替换二阶扩散项为四阶稳定项来稳定方程的数值格式,进一步采用多传感器模式以降低测量误差的影响,从而得到多个假定源反演的准可逆方程。最后,利用计算流体动力学(CFD)计算的气流速度和下游传感器位置测量放射性污染物的“浓度-时间”信息为输入,选取合适的稳定系数,求解污染物源位置的后向概率密度函数(PDF),PDF最高的位置是定位的污染物源位置。通过对多个未知释放源进行分组的测试,说明了该模型具有一般适用性。结果显示,针对封闭空间内的对流扩散环境,本反演模型能较为准确追溯到颗粒污染物源项位置。

关键词: 泄漏事故, 污染源识别, 准可逆方法

Abstract: After a radioactive leakage occurs in nuclear facilities, it is generally difficult to directly observe the release point of the source term. The location information of the source term could be obtained indirectly by using radiation monitoring data in the field and the inversion calculation of the diffusion model. Based on the quasi-reversible method, considering the aerosol particle gravity and Brownian diffusion, a direct inversion model for radioactive source terms in a closed space was carried out in this work. The k-epsilon turbulence equation and the convection-diffusion equation of particle pollutant diffusion were established by considering the typical aerosol dynamics parameters and combining the particle Eddy diffusion rate in the turbulent flow field. Then, by forcibly inverting the time step and replacing the second-order diffusion term with the fourth-order stable term, the numerical format of the equation is stabilized. Furthermore, a multi-sensor mode is adopted to reduce the impact of measurement errors, resulting in the inversion of quasi-reversible equations for multiple nominal sources. Finally, taking the “c-T” information of the sensor position as input, an appropriate stability coefficient for inversion was selected. The results show that this inversion model can accurately trace the location of the source term of particle pollutants in the convective diffusion environment within a closed space.

Key words: leakage accidents, identification of pollution sources, quasi-reversible method

中图分类号:

TL75+1

张明昊, 吴荣俊, 陈艳, 倪木一, 蒋应伍, 王雨晴. 基于准可逆方法的封闭空间放射性气溶胶溯源研究[J]. 辐射防护, 2024, 44(S1): 18-23.

ZHANG Minghao, WU Rongjun, CHEN Yan, NI Muyi, JIANG Yingwu, WANG Yuqing. Study on traceability of radioactive aerosols in closed spaces based on quasi reversible method[J]. RADIATION PROTECTION, 2024, 44(S1): 18-23.

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