Vapor--liquid--solid phase equilibria of radioactive sodium salt wastes at Hanford

Abstract

This system simuZates radioactive sodium saZt wastes stored in underground tanks at Sanford. Equitibrium water vapor pressure of the aqueous phase and solub€Zity of the saZts were measured. as a function of temperaturo and NaOH concentration.These data are used to predict deZiquescence of stored saZt.wastes and also to predict the chemicaZ / identity of soZid residues from evaporation of Ziquid wastes.

Precipitation and Deposition of Aluminum-Containing Phases in Tank Wastes

“…1,2 Processes designed to minimize the volume of high-level waste through conversion to glassy phases require transporting waste solutions near-saturated with aluminum-containing species from holding tank to processing center. The uncontrolled precipitation within transfer lines results in clogged pipes and lines and fouled ion exchangers, with the potential to shut down processing operations.…”

“…The uncontrolled precipitation within transfer lines results in clogged pipes and lines and fouled ion exchangers, with the potential to shut down processing operations. 2 The principal focus of our research was to maintain the fluidity of aluminum-or silicon-containing suspensions and solutions during transport, whether by preventing particle formation, stabilizing colloidal particles in suspension, or by combining partial dissolution with particle stabilization. We have found that all of these can be effected in aluminum-containing solutions using the simple organic, citric acid.…”

“…Studies on simulated tank wastes near saturation and under basic conditions found that the solubility of aluminum first increased and then decreased with increasing hydroxide concentrations. 2 The kinetics of both precipitation and dissolution of Alcontaining phases were shown to depend on the nature and solubility of the aluminumcontaining species present in the system. In the determination of overall aluminum solubility under conditions of near saturation and high pH, several soluble monomeric and polymeric species were found to be present in solution.…”

Thermal reactivity of mixtures of VDDT lubricant and simulated Hanford Tank 241-SY-101 waste

“…The substantial water content found in Bryan's dried simulant illustrates how strongly this simulant retains water and suggests that actual lOlSY waste should be slow to dry during the VDTT removal operation; wastes containing substantial amounts of sodium hydroxide can retain substantial amounts of water (Scheele, Bredt, and Sell 1996;Barney 1976;Fauske et al 1995).…”

Practical Modeling of aluminum species in high-pH waste

“…Figure 1 (Barney 1976) is shows solubilities of aluminum species versus sodium hydroxide. The curves with the dotted lines are from literature for the Na,O -A1203-H20 system.…”