Measurement of Cesium and Uranium Distribution Coefficient (Kd) in the Iranian Radioactive Repository Site

Today, the risk of radioactive waste release containing heavy metals into the environment, as well as their penetration into surface and underground water sources, has become a global concern. Hence, it is necessary to investigate the polluting elements distribution in the soil by the disposal site safety assessment studies. One of the important parameters in the radionuclide leakage and migration rate is the distribution coefficient (Kd), which can give more accurate data about the radionuclide migration rate from the site. In this study, the Kd of cesium and uranium radionuclides, the most important elements in radioactive waste repositories, are performed in the Anarak Trench-type near-surface disposal site using batch and column methods. The results of fitting the data with different adsorption isotherm models showed that the Langmuir model has the most agreement with the results. The Kd of cesium was measured in the range of 15 to 47 and 9 to 69 cm3/g for both column and batch methods, respectively. On the other hand, this criterion was estimated at the range of 55 to 80 and 115 to 155 cm3/g for both the same methods and concentrations. Moreover, the comparison of the results shows that the experiments have an appropriate consistency with international standards.