Thermodynamic Modeling of Savannah River Evaporators

Weber, C.F.

doi:10.2172/788505

Cited by 11 publications

(13 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…One disadvantage of using oxalic acidic to clean SRS HLW tanks is that oxalic acid must be carefully managed during decontamination applications because of the sparing solubility of its sodium salt in representative HLW process supernatant equaling about 0.028 M (Weber, 2001;Wiley, 1978). Because of the low solubility, sodium oxalate precipitates form from the oxalic acid solutions in the sodium-rich environment.…”

Section: Appendices Appendixmentioning

confidence: 99%

Remediation of Spent Oxalic Acid Nuclear Decontamination Solutions Using Ozone

Ketusky

2018

View full text Add to dashboard Cite

The Savannah River Site (SRS) has forty-three remaining very large underground tanks containing significant quantities of nuclear waste generated primarily from cold-war radiochemical separations. All of the tanks eventually must be closed. As part of decommissioning/closing the nuclear waste tanks, even residual quantities of the waste must be removed. Although most sludge can be removed mechanically, chemically cleaning (i.e. decontamination) with oxalic acid is used to aid in the removal of residual quantities. Although oxalic acid works for cleaning the tanks, its downstream impacts are considered detrimental. To better understand and quantify the impacts, detailed models were developed to account for different potential processing strategies for handling the spent oxalic acid nuclear decontamination slurries. Although the results vary, the models show that regardless of the oxalate handling strategies: 1) significant washing to decrease sodium concentration/solids concentration in vitrification feed will be required, and 2) the creation of copious future additions of feed for salt processing will be unavoidable. Using a Theory of Inventive Problem Solving (TRIZ) approach, a modified form of the Chemical Oxidation Reduction Decontamination (CORD) ultraviolet (UV) light was identified as being used with an analogous but already resolved problem that could be adapted to SRS HLW tank cleaning. A novel preliminary process called Enhanced Chemical Cleaning (ECC) was envisioned. Many people have aided me in this research and made this thesis possible. Naming all key people would likely be impossible; therefore, I will probably leave someone out. In advance, please accept my apologies. From my time at High-Level Waste Engineering, I would like to thank Renee Spires, Tommy Caldwell, Mark Mahoney, and Neil Davis. They were the first people to honestly trust my novel TRIZ determination that using oxalic acid to clean the High-Level Waste tanks, tied closely to decomposing the resultant spent acid solution represented the "ideal solution." At Savannah River National Laboratory, Chris Martino and Bill King, who spent considerable time helping me understand much of the oxidation chemistry. At AREVA NP (Lynchburg) Dennis Jones, John Remark, Ray Beatty, and Sarah Evans, all who helped me gain valuable insights. My supervisor Professor Colin Boxall who encouraged me throughout the process. And finally, to my many friends and colleagues that supported me during this research. viii

show abstract

Section: Appendices Appendixmentioning

confidence: 99%

Remediation of Spent Oxalic Acid Nuclear Decontamination Solutions Using Ozone

Ketusky

2018

View full text Add to dashboard Cite

show abstract

“…The nuclear magnetic resonance (NMR) connectivity group associated with each species is noted in Table 4. NMR results and connectivity groups have been discussed earlier (Hunt et al, 1999;Weber, 2001a;Weber, 2001b). For each of the species in Table 4, a useful model requires parameters that describe interactions in solution.…”

Section: Silicate Speciesmentioning

confidence: 99%

“…For NMR data and solubility in either sodium hydroxide or sodium nitrate solutions, the data analysis and regressions are similar to those performed in previous work (Hunt et al, 1999;Weber, 2001a;Weber, 2001b). The measured densities were used to convert the equilibrium concentrations to molal units so that they could be used in the regressions and the model predictions.…”

Section: Silicate Speciesmentioning

confidence: 99%

“…The model calculation generally matches the data within the experimental error. At 25ºC, the predictions of the new silicate model are better than the calculations of the earlier versions of the silicate model (Hunt et al, 1999;Weber, 2001a;Weber, 2001b). The silicate model was then tested at elevated temperatures to determine its applicability to the SRS evaporator system.…”

Section: Silicate Model Predictionsmentioning

confidence: 99%

“…During the past few years, a general model using the SOLGASMIX code has been developed for silicate behavior. An initial modeling effort (Hunt et al, 1999) was able to describe most major phenomena such as increasing solubility with increasing pH, polymerization in the pH region of 10.6 to 12.2, and solubility in neutral solutions at 25 o C. This model was modified to include temperatures up to 100 o C so that the model could be used to predict the formation of aluminosilicates (Weber, 2001a) and to evaluate other waste processing issues at the SRS (Weber, 2001b). This work represents additional refinement of the basic silicate model between 25 and 100 o C and its adaptation to solutions with sodium nitrate as well as sodium hydroxide.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations