CENTRIFUGE MODELING OF CONTAMINANT TRANSPORT THROUGH SOILS
Nuclear industry generates radioactive waste, which requires safe handling and disposal. Geological formations are characterized for their suitability as a potential disposal facility, based on geological, hydrological and geochemical properties, and impact of these properties on the integrity of these wastes in the long run. Migration of radionuclides depends on the type and condition of the rock mass and hence simulation of waste-rock mass interaction becomes essential.
Usually, laboratory and field experiments are conducted to model and assess radionuclide migration though the rock mass. However, this is an extremely slow process and hence these studies are incapable of yielding results in a reasonable time. This calls for development of an accelerated testing methodology, which is capable of predicting fate of the radionuclides in a reasonable time.
In recent years, utility of a geotechnical centrifuge for modeling contaminant transport through the soil mass has been demonstrated by several researchers, successfully. However, no such attempt has been made to model radionuclide migration through the rock mass. With this in view, a methodology to simulate migration of various ions such as Chloride, Iodide, Cesium and Strontium through the intact and fractured rock mass has been developed, in the present study. Conventional diffusion tests (1-g tests) and centrifuge tests (N-g tests) have been conducted to evaluate the diffusion coefficient of these ions. The obtained results have been compared to demonstrate validity of 'modeling of models' for the diffusion coefficient and the diffusion time. The study brings out the utility of the geotechnical centrifuge in modeling migration of radionuclides through the rock mass and predicting their fate in the long run.
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