Characterization of local soils and study the migration behavior of radionuclide from disposal site of LILW

摘要

Migration behavior of radionuclide is one of the most important factors to be considered for the long-term safety assessment of a radioactive waste disposal facility in a wet geological formation. In the present study, laboratory based column experiments have been carried out to assess the radionuclide migration behavior of ~(137)Cs and ~(60)Co and to evaluate the retardation factor through a clay soil layers using gamma spectrometry. Investigation was performed for a range of particle sizes and fixed column lengths to determine an appropriate value of migration rate of ~(137)Cs and ~(60)Co. The distribution pattern of particle size in soil samples were measured by sieved method. Two different particle sizes (≤90 μm and mixed size) were used in the column experiments. The migration rate in the clay type soil layer of particle size ≤90 μm was found by the order of ~(60)Co > ~(137)Cs. The maximum migration length of ~(60)Co in the soil layer was found to be 0-25 cm, however in the case of ~(137)Cs it was found at a maximum length of 0-10 cm. The distribution coefficient of ~(60)Co was found nearly same as that of ~(137)Cs. The retardation factor was found to be 1.79 and 1.94 for ~(60)Co and ~(137)Cs, respectively. The experimental breakthrough from this study indicates that the amount of radioactive cesium and cobalt released depends upon the composition of the soils.