Study on immobilization of the spent ion exchange resins of Tehran research reactor in borosilicate glass

The present study examined the vitrification of spent ion exchange (IEX) resins in a borosilicate glass matrix on the laboratory scale. For this purpose, the simulated spent IEX resin waste prepared by doping non-radioactive cobalt and cesium elements on a combination of cationic and anionic resins was employed. For glass wasteform preparation, heat-treated (at 150 °C) spent IEX resin was mixed with borosilicate glass ferrite in the range of 20-40 weight percent and then melted at 1200 °C. To evaluate the prepared glass wasteforms, their volume reduction ratio (VRR) and chemical stability were investigated. According to the obtained results, with the increase in the spent IEX resin loading, the volume reduction ratio of the final wasteform increases. However, in the samples with spent IEX resins loading higher than 30 wt.%, phase separation (white color containing insoluble sulfate) was observed on the surface of the glass. Investigations showed that glass wasteform containing 30 wt.% spent IEX resins provides the best conditions for waste immobilization. The relative volume reduction ratio of this sample was measured as 86.61%. The normalized leaching rate of cesium and cobalt from this wasteform was calculated as 7.43×10-5 and 6.93×10-5 g.m-2.day-1, respectively, using the PCT method.