Sorption behavior of radionuclides in the geo-environment of Kakrapar site

Studies pertaining to migration behavior of Niobium in the soil of Kakrapar site were carried out. 12 nos. of soil samples and ground water collected from NPCIL Kakrapar site were characterized with an objective to evaluate the sorption potential of soil towards Niobium. Detailed elemental characterization is planned to understand the type of soil. Sorption potential with respect to Cs and Sr were determined for reference purpose. Equilibration studies for Cs and Sr were carried out with Kakrapar site ground water spiked with ¹³⁷Cs and ⁹⁰Sr, whereas equilibration experiments for Niobium was carried out by using Niobium pentachloride (NbCl₅) salt of analytical reagent grade. Since Nb is one of the components of Pressure Tube material, it forms activation product (⁹⁴Nb) during reactor operation, whose migrational behavior may have environmental impact after disposal of Pressure Tube. Initial concentrations of Cs, Sr and Nb in ground water were arbitrarily chosen, final concentration left in supernatant after equilibration and Kd-values obtained are presented