Multiple Ion Exchange Column Tests for Cesium (CS+) Removal from Hanford Site Tank 241‐AW‐101 with SuperLig® 644 Resin

Abstract

Six cycles of loading, elution, and regeneration were performed to remove cesium (Cs+) from a Hanford Site tank waste sample using SuperLig® 644 resin. The sample, which was retrieved from Tank 241‐AW‐101, was diluted to 5.09 M Na+ and processed through dual ion exchange columns to remove 137Cs. Each column had an inside diameter of 1.45 cm and a height of 30 cm; and contained 15 mL of wet resin in the sodium form. The columns, designated as primary (lead) and polishing (lag), were connected in series during loading, but they were separated during elution and regeneration. The cesium loading on the primary column during the six cycles ranged from 160 to 225 bed volumes (BV) at <50% breakthrough. A gradual decline of the resin loading performances was observed as a function of number of loading cycles. For all cycles, the percent removal of cesium (137Cs) was greater than 99.99% and the decontamination factors (DFs) achieved were higher than 1.0 × 104. Elution of the resin with 0.5 M nitric acid at 25 ± 2°C was effective. Approximately 99% of the 137Cs bound on the resin was eluted with less than 15 BV of the eluent (0.5 M nitric acid). The cumulative dose absorbed by the resin in the primary column was 1.99 × 107 rad with a 20% loss of ion exchange capacity was at 50% breakthrough after completing six loading cycles.