Characterization of CST Post-Processing AP-105 Hanford Tank Waste

Technical Report · Wed Sep 01 04:00:00 EDT 2021

DOI:https://doi.org/10.2172/1829476· OSTI ID:1829476

Campbell, Emily L. ^[1]; Fiskum, Sandra K. ^[1]; Peterson, Reid A. ^[1]

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1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

The primary goal of the Tank Side Cesium Removal (TSCR) system, under development by Washington River Protection Solutions, LLC (WRPS), is to remove entrained solids and ¹³⁷Cs from the Hanford tank waste supernate to expedite production of low-activity waste. Ion exchange (IX) testing of 10.9 L of waste from Hanford tank 241-AP-105 (AP-105), performed by Pacific Northwest National Laboratory, used a lead-lag-polish column format, with a bed volume of 10 mL per column, to decontaminate tank waste supernate using crystalline silicotitanate (CST) as the IX media. The AP-105 Cs IX processing test, discussed elsewhere, resulted in a shorter transition zone (i.e., steeper load curve) than those defined by wastes from tanks 241-AP-107 and 241-AW-102.1 The shorter transition zone was indicative of a matrix effect retarding Cs capacity. Therefore, aliquots of spent CST from the lead, lag, and polish columns were subjected to a digestion protocol to quantify analytes retained by the CST and extrapolate the impact on Cs capacity. The spent CST was digested using a combination of 5 M HNO₃ and H₂O₂ with vigorous heating and stirring. Due to the radiation dose accompanying the ¹³⁷Cs on the CST columns, a secondary Cs separation by ammonium molybdophosphate embedded in polyacrylonitrile (AMP-PAN) was performed to separate the ¹³⁷Cs from the CST so the samples could be contact-handled for analysis outside of a shielded facility.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1829476
• Report Number(s): PNNL-31903
• Country of Publication: United States
• Language: English

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