单裂隙介质中核素迁移模型的解析解及其应用

Analytical solution and its application of modeling nuclide transport model in single fractured media

摘要:

为了解核素在裂隙介质中的迁移规律,应用双重介质理论,分别建立描述核素在裂隙域和基质域中迁移的基本微分方程,通过二者在裂隙域与基质域交接处流量和溶质的连续性,利用拉普拉斯变换推导出描述单裂隙中一端具有指数衰减注入源的解析解.以Th-229、Cs-135及Se-79为研究对象,利用该解析解预测了这些核素的相对浓度在裂隙域与基质域中随时间和空间的变化结果,模拟结果表明,该解析解可应用于裂隙介质中的核素迁移、地下水污染等研究.

Abstract:

To know the law of nuclide transport in fractured media,the basic differential equations of nuclide transport in fracture and matrix were obtained,which were coupled at the interface between the fracture and matrix,and the general analytic solutions of nuclide transport in single fractured media with exponential attenuation source in fracture were deduced by Laplace transform.Moreover,the transport of Th-229,Cs-135 and Se-79 were simulated with the analytic solutions,and the relative concentration of these nuclide in fracture and matrix were predicted.These simulation results show that the analytic solutions can be used to solve the problems of nuclide transport,groundwater contamination in fractured media,etc.