Cesium-removal flow studies using ion exchange

The development, selection, and implementation of technologies to be used in removing cesium from radioactive liquid wastes in preparation for their final disposition is discussed. The methodology involved testing several proposed sorbents in ion-exchange columns using actual liquid wastes from underground storage tanks at U.S. Department of Energy sites. The sorbents initially tested included resorcinol-formaldehyde resin (RF), CS-100 resin, SuperLig 644C resin, 3M WEB with embedded SuperLig 644, granular potassium cobalt hexacyanoferrate, and granular crystalline silicotitanates (CSTs). The results of the bench-scale testing were used to select the sorbent for the full-scale Cesium Removal Demonstration Project (CsRD). This project will treat up to 25,000 gal of radioactive supernatant stored in the Melton Valley Storage Tanks (MVSTs) at Oak Ridge National Laboratory (ORNL). The demonstration system is modular in design and will process supernatant at flows up to 5 gal/min through 12-in.-diam columns. Following the demonstration the system will be used for routine processing of tank waste at ORNL. To show their applicability to wastes at other sites, RF and CST sorbents were tested in a bench-scale column using a diluted Hanford supernatant liquor (double-shell slurry feed) from tank 241-AW-101. The results are compared with those from tests of MVST supernatant.