Vitrification and Product Testing of C-104 and AZ-102 Pretreated Sludge Mixed with Flowsheet Quantities of Secondary Wastes

Smith, Gary L.; Bates, Rick J.; Goles, R.W.; Greenwood, Lawrence R.; C, Lettau, Ralph; Piepel, Gregory F.; Schweiger, Michael J.; Smith, Harry D.; Urie, Michael W.; Wagner, Jerome J.

doi:10.2172/786784

Cited by 11 publications

(10 citation statements)

References 17 publications

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“…2003 The potassium hydroxide (KOH)-potassium nitrate (KNO 3 ) fusion-dissolution procedure is the most commonly used method for solubilization of Hanford tank sludge samples for chemical analysis by inductively coupled plasma-mass spectroscopy (ICP-MS) and other methods (De Lorenzo et al 1994;Simpson 1994;Fiskum et al 2000;Smith et al 2001). Benefits of this procedure include effective metathesizing of insoluble salts such as SrSO 4 , PuPO 4 , PuF 3 , and ThF 3 into acid soluble hydroxides; fusion completed at relatively low temperature (550°C) compared to other fluxing agents, such as 1100°C for the LiBO 2 (lithium metaborate) fluxing agent; and use of nickel or zirconium crucibles, as opposed to the more costly platinum crucibles, for the fusion.…”

Section: Sludge Composition By Fusion and Acid Digestionsmentioning

confidence: 99%

Hanford Tank 241-C-106: Residual Waste Contaminant Release Model and Supporting Data

Deutsch¹,

Krupka²,

Lindberg³

et al. 2007

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The CH2M HILL Hanford Group, Inc. (CH2M HILL) is producing risk/performance assessments to support the closure of single-shell tanks at the U.S. Department of Energy's Hanford Site. As part of this effort, staff at Pacific Northwest National Laboratory were asked to develop release models for contaminants of concern that are present in residual sludge remaining in tank 241-C-106 (C-106) after final retrieval of waste from the tank. The primary contaminants of concern in the sludge are 99 Tc, 238 U, 129 I, and Cr because of their potential mobility in the environment and the long half-lives of the radionuclides. A key result from this work is that high percentages (>90%) of these primary contaminants are not readily leachable from the residual waste. This minimizes their future release rates to the environment, and is similar to 99 Tc results found in related studies of sludges from tanks AY-102, C-203, and C-204.Developing release models consists of laboratory testing to produce contaminant release data and a conceptual source release model. After development, the release model can be incorporated into a fate and transport model as part of a long-term risk assessment for the closed tank.Initial laboratory tests (Tier 1) were conducted to characterize the sludge and identify water-leachable constituents. Based on the results of Tier 1 tests, additional analyses were performed to augment the characterization of the material and determine the controlling mechanism(s) for release of contaminants. Tier 2 tests consisted of X-ray diffraction (XRD) and scanning electron microscopy/energy dispersive spectrometry (SEM/EDS) analyses of the solids to identify reactive phases, and selective extractions to quantify the release of contaminants from particular solid phases.The laboratory results of sludge and liquid testing were used to develop source term models that describe the release of contaminants as infiltrating water contacts the solids in the future. These models simulate the geochemical system in the tank sludge and take into account interactions between the solution phase and the contaminant-containing solids. The release models are simplifications of the complex geochemical interactions occurring; however, they adequately represent the release of the primary contaminants of concern from the sludge as measured in the laboratory tests.Because of the highly complex chemical nature of tank C-106 residual sludge, clear and quantitative phase associations of the contaminants of concern with the phases known to exist in the sludge are difficult to specify. Although the various characterization methods employed in this study have revealed a number of important observations and have provided valuable data for constructing a scientifically defensible release model, many questions remain. Because a thorough understanding of all the important phase associations for the contaminants of concern cannot be developed at this time, an empirically based release model has been developed. Although less satisfying from a mechanistic ...

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Section: Sludge Composition By Fusion and Acid Digestionsmentioning

confidence: 99%

Hanford Tank 241-C-106: Residual Waste Contaminant Release Model and Supporting Data

Deutsch¹,

Krupka²,

Lindberg³

et al. 2007

View full text Add to dashboard Cite

show abstract

“…The potassium hydroxide (KOH)-potassium nitrate (KNO 3 ) fusion-dissolution procedure is the most commonly used method for solubilization of Hanford tank sludge samples for chemical analysis by inductively coupled plasma-mass spectroscopy (ICP-MS) and other methods (De Lorenzo et al 1994;Simpson 1994;Fiskum et al 2000;Smith et al 2001). Benefits of this procedure include: effective metathesizing of insoluble salts such as SrSO 4 , PuPO 4 , PuF 3 , and ThF 3 into acid soluble hydroxides; completed fusion at relatively low temperature (550ºC) compared to other fluxing agents, such as 1100ºC for the LiBO 2 (lithium metaborate) fluxing agent; and use of nickel or zirconium crucibles, as opposed to the more costly platinum crucibles, for the fusion.…”

Section: Sludge Composition By Fusion Analysis and Acid Digestionmentioning

confidence: 99%

Hanford Tanks 241-C-203 and 241-C-204: Residual Waste Contaminant Release Model and Supporting Data

Deutsch¹,

Krupka²,

Lindberg³

et al. 2004

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This report describes the development of release models for key contaminants that are present in residual sludge remaining after closure of Hanford Tanks 241-C-203 (C-203) and 241-C-204 (C-204). The release models were developed from data generated by laboratory characterization and testing of samples from these two tanks. Key results from this work are that future releases from the tanks of the primary contaminants of concern ( 99 Tc and 238 U) can be represented by relatively simple solubility relationships between infiltrating water and solid phases containing the contaminants. In addition, it was found that high percentages of 99 Tc in the sludges (20 wt% in C-203 and 75 wt% in C-204) are not readily water leachable, and, in fact, are very recalcitrant. This is similar to 99 Tc results found in related studies of sludges from Tank AY-102 (Lindberg and Deutsch 2003;Krupka et al. 2004). These release models are being developed to support the tank closure risk assessments performed by CH2M HILL Hanford Group, Inc., for the U.S. Department of Energy.The material used for testing consisted of sludge samples collected from the tanks in September 2003. Initial (Tier 1) testing of the sludges consisted of 1) fusion analysis and acid digestion to determine the total composition of the sludges and 2) water leaching to estimate the soluble portion of the solids. Based on the results of these tests, subsequent analyses were conducted (Tier 2). These included X-ray diffraction (XRD) measurements to identify crystalline solids and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) analysis to provide a close-up view of the morphologies of the sludge material and identify the major constituents of individual minerals and amorphous solids. Periodic replenishment and selective extraction tests were also conducted during the Tier 2 tests to further evaluate water leachability and identify solid phases limiting the release of contaminants to solution. The test data were used to develop conceptual contaminant release models based on a series of solubility controls.The 99 Tc release model developed from the laboratory testing of C-203 and C-204 sludges is based on the concentrations and solubilities of technetium-bearing solids in contact with pore water migrating through the sludges. There are two stages of technetium release to solution: The 238 U release model for C-203 and C-204 sludges is based on the concentrations and solubilities of uranium-and sodium-bearing minerals in contact with pore water migrating through the sludges. There are three stages of uranium release to solution:1. Initially, soluble čejkaite [Na 4 (UO 2 )(CO 3 ) 3 ] and a sodium nitrate solid are present in the sludges at concentrations of 0.16 g U/g-sludge and 0.22 g NaNO 3 /g-sludge for C-203 and 0.068 g U/g-sludge and 0.04 g NaNO 3 /g-sludge for C-204. The common ion effect due to Na + limits the solubility of čejkaite to 0.19 g U/L until all the NaNO 3 is dissolved. The solubility of NaNO 3 is constant at 629 g/L.2. After all the ...

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“…The KOH-KNO 3 fusion-dissolution procedure is the most commonly used method for solubilization of Hanford Site tank waste samples for chemical analysis by inductively coupled plasma-mass 2.3 spectroscopy (ICP-MS) and other methods (De Lorenzo et al 1994;Simpson 1994;Fiskum et al 2000;Smith et al 2001). Benefits of the KOH-KNO 3 fusion-dissolution procedure include effective metathesizing of insoluble salts into acid soluble hydroxides; completing sample fusion at relatively low temperature (550ºC) compared to other fluxing agents, such as 1100ºC for the LiBO 2 fluxing agent; and allowing use of Ni or Zr crucibles, as opposed to the more costly Pt crucibles, for the fusion.…”

Section: Residual Waste Composition By Fusion Analysis and Acid Digesmentioning

confidence: 99%

Hanford Site Tank 241-C-108 Residual Waste Contaminant Release Models and Supporting Data

Cantrell¹,

Krupka²,

Geiszler³

et al. 2010

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SummaryThe U.S. Department of Energy (DOE) Office of River Protection prime contractor, Washington River Protection Solutions, LLC (WRPS), is responsible for the storage, retrieval, and disposal of Hanford Site tank waste. As part of this effort, WRPS contracted with Pacific Northwest National Laboratory to conduct testing for selected key contaminants present in residual waste remaining in the single-shell tank 241-C-108 (C-108). Release model data will be used to support tank closure performance assessments that will be performed by WRPS. This report presents the results from laboratory characterization, testing, and analysis of a tank C-108 post modified sluicing residual waste composite sample (designated 20578). The tank C-108 residual waste sample was taken following an assessment that determined through material balance data the modified retrieval sluicing system deployed at the tank could no longer efficiently retrieve waste (met the limit of the technology). These studies were completed to characterize concentration and form of contaminant of interest in the residual waste; assess the leachability of contaminants from the solids; and develop release models for contaminants of interest. It is expected that additional retrieval processing will take place. As a result, the sample analyzed here is not expected to represent final retrieval sample. Total elemental analysis using the U.S. Environmental Protection Agency (EPA) acid digestion method, indicates that tank C-108 partial retrieval residual waste (sample 20578) is composed of the following major elements Na at 15.5%, Al at 12.3%, P at 4.0%, Fe at 1.6%, Ni at 0.22%, U at 0.18%, and Mn at 0.13%. Concentrations of 99 Tc and 238 U were determined to be 0.636 µg/g waste (0.0108 µCi/g) and 1870 µg/g waste (6.27 × 10 -4 µCi/g). O], sodium phosphate (Na 3 PO 4 ), nickel oxide hydroxide (NiOOH), and nitratine (NaNO 3 ). Solid phase characterization by scanning electron microscopy/energy dispersive spectrometry (SEM/EDS) analyses indicated the majority of the particles in the as-received tank C-108 composite sample are composed of Al-Na-O-P-F, Al-Na-O-P, Na-O-P-F, Na-O-P, Al-Na-O, and Na-O, all in variable proportions. Note that all phases could also potentially contain H and C, which cannot be quantified by EDS. Combining the XRD with the SEM/EDS results, the following conclusions can be made regarding the presence of solid phases in the tank C-108 residual waste composite sample:• Gibbsite was the major phase present and appears to be coated and mixed with variable amounts of phases such as natrophosphate, sodium fluoride phosphate hydrate, sodium phosphate, sodium carbonate, sodium hydroxide, and sodium nitrate• Fe-oxides occurred as a minor phase. Its particles were coated and mixed with variable amounts of other solid phases such as natrophosphate, sodium fluoride phosphate hydrate, sodium phosphate, sodium carbonate, sodium hydroxide, and sodium nitrate• Minor amounts of Ni and traces of other metals such as Pb, Zn, and Cu, were associated with the Fe-ox...

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Vitrification and Product Testing of C-104 and AZ-102 Pretreated Sludge Mixed with Flowsheet Quantities of Secondary Wastes

Cited by 11 publications

References 17 publications

Hanford Tank 241-C-106: Residual Waste Contaminant Release Model and Supporting Data

Hanford Tank 241-C-106: Residual Waste Contaminant Release Model and Supporting Data

Hanford Tanks 241-C-203 and 241-C-204: Residual Waste Contaminant Release Model and Supporting Data

Hanford Site Tank 241-C-108 Residual Waste Contaminant Release Models and Supporting Data

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