低中放核素在地下水环境运移的动力学研究

针对处置库中低中放核素释放对地下环境潜在性污染的严重性，建立了核素在包气带和含水层中联合迁移的数值模型，利用所建立模型对某一处置场核素迁移的动力学行为进行环境预测。数值模拟结果表明：包气带对于吸附性较强的核素具有很大的阻滞作用，对于低分配系数的核素阻滞作用较弱；衰变系数对含水层中核素的迁移起到了重要作用，随着衰变系数的增大，地下含水层中的核素体积浓度逐渐降低，并且分配系数的大小直接影响着核素在含水层中体积浓度分布曲线的形状。采用系统耦合数学模型来研究核素在包气带和含水层中的运移是预测核素污染的重要手段和有效方法，可为核素在地下处置库中安全处置及环境影响的评价提供科学依据和技术指导。

Study on dynamic transport model of low level radioactive waste in groundwater system

In the article, considering the potentially severe pollution of the subsurface environment from the low level radioactive waste, the dynamic integrated transport model of low level nuclide in vadose and saturate zones has been established and is used to predict the dynamic action of the nuclide in a disposition spot. The simulation result shows that vadose zone can rigorously retard those nuclides with vigorous adsorbility, i.e. the bigger the nuclide decay coefficient is, the more the nuclide is retarded in vadose zone and the less the nuclide concentration in aquifer is, and that the distribution coefficient directive affects the form of the nuclide concentration curve in an aquifer. It is conclude that systematic coupling numerical model is an effective method to study the nuclide transport in vadose and saturate zones and can offer scientific evidence and technique guide for the safe disposition of nuclide waste and environmental assessment.