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SUMMARYIdaho Nuclear Technology and Engineering Center 300,000-gallon vessel WM-189 was filled in late 2001 with concentrated sodium bearing waste (SBW). Three airlifted liquid samples and a steam jetted slurry sample were obtained for quantitative analysis and characterization of WM-189 liquid phase SBW and tank heel sludge. Estimates were provided for most of the reported data values, based on the greater of (a) analytical uncertainty, and (b) variation of analytical results between nominally similar samples.A consistency check on the data was performed by comparing the total mass of dissolved solids in the liquid, as measured gravimetrically from a dried sample, with the corresponding value obtained by summing the masses of cations and anions in the liquid, based on the reported analytical data. After reasonable adjustments to the nitrate and oxygen concentrations, satisfactory consistency between the two results was obtained. A similar consistency check was performed on the reported compositional data for sludge solids from the steam jetted sample.In addition to the compositional data, various other analyses were performed: particle size distribution was measured for the sludge solids, sludge settling tests were performed, and viscosity measurements were made.WM-189 characterization results were compared with those for WM-180, and other Tank Farm Facility tank characterization data.A 2-liter batch of WM-189 simulant was prepared and a clear, stable solution was obtained, based on a general procedure for mixing SBW simulant that was develop by Dr. Jerry Christian. This WM-189 SBW simulant is considered suitable for laboratory testing for process development. iv v ACKNOWLEDGEMENTS

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A status is presented of the parameterization during FY2003 of an association-based Pitzer model to simulate chemical and phase equilibria of acid-chloride-nitrate-mercury aqueous electrolyte systems at 0-100û C within the industry-standard process simulator, ASPEN Plus. Compatibility with ASPEN Plus requires that the Pitzer model used be limited to the third virial coefficient and have the values of b and α 1 as originally proposed by Pitzer. Two aqueous models for 0-110û C at atmospheric pressure were parameterized in FY03. The model for the aqueous H + -K + -Na + -Cl -system is applicable for 0-16 molal, and the HNO 3 -H2O for 0-20 molal. An association-based Pitzer activity coefficient model is combined with Henry's law to predict activity/osmotic coefficient and VLE. The chloride model also predicts KCl and NaCl solubility, while the nitric acid model has the unique capability of predicting extent of dissociation with an average absolute deviation of 1.43%. The association-based approach presented here extends the utility of the molality-based Pitzer model past 6 molal to predict activity/osmotic coefficients up to 16-20 molal. The association-based approach offers the additional benefits of predicting extent of dissociation and of allowing the Pitzer model to be fully utilized in commercial simulators, such as ASPEN Plus, that require accounting for association to implement Henry's law. The Pitzer models presented here provide the chemical process simulation engineer with a superior alternative to the Electrolyte NRTL model that can easily be used in ASPEN Plus. iv EXECUTIVE SUMMARYA status is presented of the parameterization during FY2003 of an association-based Pitzer model to simulate chemical and phase equilibria of acid-chloride-nitrate-mercury aqueous electrolyte systems. This work was funded by the Laboratory Directed Research and Development (LDRD) program at the Idaho National Engineering and Environmental Laboratory (INEEL). The Pitzer model was originally developed for the 0-6 molal range, so many of the Pitzer parameter values in the literature are not applicable to high ionic-strength, complex mixtures, such as 10 molal SBW. The objective of this project is to obtain association-based parameters for the Pitzer model that will allow practitioners to perform process design involving liquid speciation, vapor-liquid, and solid-liquid equilibria of high ionic-strength, complex, electrolyte mixtures at 0-100û C within any process simulator where Pitzer's model has been implemented (in particular, ASPEN Plus, which has been selected for process modeling at INEEL).The parameterization of two aqueous models for 0-110û C at atmospheric pressure were performed in FY03. An association-based Pitzer activity coefficient model is combined with Henry's law to predict activity/osmotic coefficient and vapor-liquid equilibrium. The bulk of the work of parameterization involved the qualification of different data types from different researchers, at similar and different temperatures. The model for the a...