Abstract
Abstract An adequate performance assessment of underground repositories of radiowaste depends on good understanding of the transport behavior of radionuclides with concerned solid. In this study, the transport behavior of selenium and cesium on granite and quartz was investigated by column experiments and LEHGC model simulations. The results suggest that the averaged retardation factor, (Rf) of granite to adsorb selenium under both groundwater and seawater is about four, indicating the sorption of selenium is insensitive to ionic strength. However, the abundant cations in seawater weaken the Cs adsorption and the Rf of granite to adsorb Cs decreases from four of groundwater to one of seawater. The limited sorption ability of quartz to adsorb selenium and cesium leads to an Rf value of one for both radionuclides no matter under groundwater or seawater. The batch experiments were also conducted to study the adsorption ability of granite and quartz to adsorb selenium and cesium. The results show that the Kd values from batch experiments are higher than those from column experiments, suggesting that the sorption of selenium and cesium under granite column does not reach equilibrium. In contrast, the Kd from batch experiments consist with that from column experiments, revealing the limited sorption ability of quartz to adsorb selenium and cesium. Moreover, chemical sequential extraction was also conducted to study the sorption mechanism of granite to selenium. The results suggest the crystalline Fe oxides are the most important minerals for granite to adsorb selenium.