(548a) Prediction of Cesium Loading on Crystalline Silicotitanate Ion Exchange Resin

At the Savannah River Site (SRS) waste saltcake stored in the SRS Tank Farms is dissolved in water and processed through the Tank Closure Cesium Removal (TCCR) system to remove radioactive cesium and strontium from the high-activity waste solution. The TCCR system is a crystalline silicotitanate (CST) ion exchange (IX) system comprised of a carousel of two small lead-lag IX columns. Concerns have been raised that cesium could accumulate on the CST resin at concentrations that exceed the safety threshold of 170 Ci/L, potentially necessitating a costly redesign of the TCCR system.

A computer model was developed by Professor Rayford G. Anthony of Texas A&M University (TAMU) to simulate IX equilibria between electrolytic solutions and CST solid resin. The TAMU model was used to estimate cesium loading on CST as a function of initial cesium concentration in the waste solution.

This paper presents the computational results for a wide range of waste solution and discusses the effects of key ions (i.e., Na⁺, OH^-, K⁺) on cesium loading.