(415d) Ion-Exchange Modeling to Support the Tank Closure Cesium Removal Process at the Savannah River Site

The Tank Closure Cesium Removal (TCCR) system is a demonstration “at-tank” process designed to remove ¹³⁷Cs from the high-level aqueous tank waste at the Savanah River Site (SRS) so that the decontaminated solution can be disposed as low-level waste. Cesium is removed by ion exchange (IX) columns using engineered IONSIV[1] R9120-B of the Crystalline SilicoTitanate (CST) media.

The current TCCR system can accommodate lead-lag (two-column) or lead-lag-guard (three-column) configurations to optimize media utilization and achieve the target decontamination. To support the TCCR operation for decontamination of Tank 10 in the SRS H Tank Farm, Savannah River National Laboratory (SRNL) utilized the following modeling applications:

1. The ZAM computer program developed by Texas A&M University for calculation of equilibrium cesium loading on the CST media.
2. The VERSE-LC code developed by Purdue University to predict ion-exchange (IX) column performances.
3. The OLI Studio[2] commercial software from OLI Systems, Inc. to calculate charge-balanced waste compositions and to estimate waste solution properties (i.e., density, viscosity, diffusivity) required as input data to ZAM and VERSE-LC.

This paper demonstrates the versatility of the ion exchange modeling in evaluating the loading of cesium on CST and the plant operational IX column performances.

[1] IONSIV is a trademark of Honeywell UOP, Inc. Des Plaines, Illinois, USA

[2] OLI is a registered trademark of OLI Sytems, Inc., of Morris Plains, New Jersey, USA