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Title: Development of Fundamental Data on Chemical Speciation and Solubility for Strontium and Americium in High- Level Waste: Predictive Modeling of Phase Partitioning During Tank Processing

Technical Report ·
DOI:https://doi.org/10.2172/833733· OSTI ID:833733

In this research program, Pacific Northwest National Laboratory and Florida State University are investigating the speciation of Sr and Am/Cm in the presence of selected organic chelating agents (ethylenediaminetetraacetic acid [EDTA], N-(2-hydroxyethyl)ethylenediaminetriacetic acid [HEDTA], nitrilotriacetic acid [NTA], iminodiacetic acid [IDA], citrate, and oxalate) over ranges of hydroxide, carbonate, ionic strength, and competing metal ion concentrations present in high-level waste stored in tanks at Hanford and other U.S. Department of Energy (DOE) sites. The project comprises integrated research tasks that approach the problem of chemical speciation using macroscopic thermodynamic measurements of metal-ligand competition reactions, molecular modeling studies to identify structures or complexes of unusual stability, and mass spectrometry measurements of complex charge/mass ratio that can be applied to mixed metalchelate systems. This fundamental information then is used to develop thermodynamic models designed to predict changes in chemical speciation and solubility resulting from various tank processing conditions. In this way we can develop new approaches that address fundamental problems in aqueous speciation and, at the same time, provide useful and practical information needed for tank waste processing.

Research Organization:
Pacific Northwest National Lab., Richland, WA; The Florida State University Department of Chemistry,Tallahassee, FL (US)
Sponsoring Organization:
USDOE Office of Environmental Management (EM) (US)
DOE Contract Number:
FG07-02ER63222
OSTI ID:
833733
Report Number(s):
EMSP-73749-2001; R&D Project: EMSP 73749; TRN: US200430%%1768
Resource Relation:
Other Information: PBD: 1 Jun 2001
Country of Publication:
United States
Language:
English