Literature Review on the Sorption of Plutonium, Uranium, Neptunium, Americium and Technetium to Corrosion Products on Waste Tank Liners

Solid Secondary Waste Data Package Supporting Hanford Integrated Disposal Facility Performance Assessment

“…In the same study, but using reducing vault concrete (a slag-containing cement), Estes et al (2012) measured a solubility in the pH 10.9 and Eh -0.40 V leachate of 4.5E-10 M Tc. Um et al (2016), using a hydrated lime, 35% OPC, and 45% BFS formulation, reported a Tc solubility of 4.3E-9 M, Thermodynamic modeling captured the data trends and the magnitude of these experimental data from the SRS reasonably well (Li et al 2012). The Tc solubility in the 3 rd stage has a lower solubility to account for the general transformation of Tc into a more soluble phase (as observed through spectroscopy; (Um et al 2013;Lukens et al 2005;Arai and Powell 2015) as the Eh of the system gradually becomes increasingly oxidized and the solid phase Tc speciation transitions to more soluble species.…”

“…Apparent solubility concentrations are proposed for use under reducing cementitious conditions for Tc and Cr. Theoretically, these COPCs have been shown to be solubility controlled (Cantrell and Williams 2012;Li and Kaplan 2012;Rai et al 1987;Bajt et al 1993), and equally important, laboratory data are available.…”

“…Much of the debris waste is described as metal, and as such it may be reasonable to assign based on COPC binding to rusted metal, or to Fe-oxyhydroxide minerals, for which there is an extensive data base. For example, a database exists for COPC desorption from the steel tank walls of dispositioned SRS tanks filled with cementitious materials (Li and Kaplan 2012). These values are based on COPC sorption/desorption to various iron oxyhydroxides at ~10.5 pH.…”