Strontium and Actinide Separations from High Level Nuclear Waste Solutions Using Monosodium Titanate 2. Actual Waste Testing

Abstract

Abstract Pretreatment processes at the Savannah River Site will separate 90Sr, alpha‐emitting and radionuclides (i.e., actinides) and 137Cs prior to disposal of the high‐level nuclear waste. Separation of 90Sr and alpha‐emitting radionuclides occurs by ion exchange/adsorption using an inorganic material, monosodium titanate (MST). Previously reported testing with simulants indicates that the MST exhibits high selectivity for strontium and actinides in high ionic strength and strongly alkaline salt solutions. This paper provides a summary of data acquired to measure the performance of MST to remove strontium and actinides from actual waste solutions. These tests evaluated the effects of ionic strength, mixing, elevated alpha activities, and multiple contacts of the waste with MST. Tests also provided confirmation that MST performs well at much larger laboratory scales (300 – 700 times larger) and exhibits little affinity for desorption of strontium and plutonium during washing. Keywords: Sorption, ion exchange, strontium, plutonium, neptunium, uranium Notes iWAC Limits as of 2002. New WAC limits are under development with the Nuclear Regulatory Commission in response to new legislation governing the disposal of high level waste produced from fuel reprocessing operations within the Department of Energy. iiUnpublished product acceptance testing of MST samples conducted at SRNL measured strontium DF values of 179±24, 186±3, and 77.7±5.1 for MST Batches 95‐QAB‐451, 00‐QAB‐417 and 96‐QAB‐281, respectively.