Analysis of spent ion exchange media: Superlig 639 and Superlig 644

The current BNFL Inc. flowsheet for the pretreatment of the Hanford High-Level tank wastes includes the use of Superlig{reg_sign} materials for the removal of {sup 137}Cs and {sup 99}Tc from the aqueous fraction of the waste. The cesium-selective Superlig{reg_sign} 644 (SL-644) and the technetium-selective Superlig{reg_sign} 639 (SL-639) have been evaluated in tests with actual waste samples. These materials have a finite processing lifetime in the plant and will need to be disposed of. The composition and level of residual radionuclide contamination is important for assessing various disposal pathways for the Superlig{reg_sign} materials. This report contains the results of analyses of subsamples of the SL-639 and SL 644 materials that have been used in small column testing of actual waste samples at the Radiochemical Processing Laboratory. The wastes that have been tested include samples from Tanks 241-AW-101 and 241-AN-107. The analyses of the spent resins include inductively coupled plasma/atomic emission spectrometry (ICP-AES) for metals, cold vapor atomic absorption (CVAA) spectroscopy for mercury, gamma energy analysis (GEA) for radionuclides and inductively coupled plasma/mass spectrometry (ICP-MS) for selected metals and radionuclides. While these results provide an indication of the analyte concentrations that may be left on the spent resin, they do not fully represent the concentrations that may be found after extended plant processing with additional load/elute cycles and different waste compositions. BNFL estimates that the SL-644 may last for 100 load/elute cycles with Envelope A and C wastes and 20 cycles with Envelope B wastes. The number of useable load/elute cycles for the SL-639 is not well defined, but is likely on the order of hundreds