Experiment on Nuclide Migration of Aquifer by Three-Dimensional Model in Laboratory Scale

In order to accurately simulate and predict the distribution of nuclides in the aquifer, the physical experiment and numerical model are used to reflect its migration and transformation. As quaternary silty loam of aquifer in Shanxi Province for example, a three dimensional model of nuclide migration in laboratory scale was established and the tracer ⁹⁰Sr was located at the center of the section by point source. After 260 d injection water by 375 mL/d, the results show that ⁹⁰Sr peak concentration migrates 3.9 cm along the direction of water flow and the peak activity concentration is 1.04×10⁴ Bq/cm³. With the increase in distance to axis, the peak activity concentration of the six regions in radial by symmetry decreases gradually. The activity concentration of upper half part is 1.02×10³-8.03×10³ Bq/cm³ and peak migration distance is about 2.7-3.6 cm. The activity concentration of lower half part is 1.86×10³-9.80×10³ Bq/cm³ and peak migration distance is about 3.3-3.6 cm. According to the concentration distribution of ⁹⁰Sr, a three-dimensional numerical model of Hydrus-3d nuclide migration was established. The distribution coefficient of strontium in silty loam is 79.0 mL/g, the longitudinal dispersion is 0.7 cm and transverse dispersion is 0.8 cm.