某核废物处置预选区中核素迁移模拟研究

核素在裂隙介质中的迁移问题是核废物深地质处置中极为关注的问题。为了解裂隙介质中核素的迁移规律,建立了基于双重介质理论的描述核素在裂隙域和基质域中迁移的基本微分方程,利用拉普拉斯变换推导出其解析解;在对西北某核废物处置场预选区地水文地质条件分析的基础上,获取相关参数,利用一维多途径核素迁移模型,选取国内在花岗岩中研究较多的核素Cs-134、Co-57、Tc-99,模拟这几种核素的相对浓度随模拟时间、迁移距离的变化规律。模拟结果表明：在其他条件都相同的情况下,Cs-134的迁移是最快的,而Tc-99迁移是最慢的。

Studies on Nuclide Transport Simulation in a Certain Potential Nuclear Waste Disposal Site

Nuclear transport in fractured media is very important for geological disposal of nuclear waste. In order to know the law of nuclide transport in fracture system,the basic differential equations of nuclide transport in fracture and matrix are obtained based on the dual media theory,and the general analytic solutions of nuclide transport in single fractured media with exponential attenuation source in fracture are deduced by Laplace transform;According to analysis of hydrogeological condition in a certain potential nuclear waste disposal site in northeast China,some parameters are obtained,and the transport of Cs-134,Co-57,and Tc-99 are simulated with one-dimensional multi-pathway model,the relative concentration of these nuclides in fracture system are predicted. The results show that the transport velocity of Cs-134 is the fastest,while Tc-99 is the slowest if the simulation condition is same.