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

Deutsch, William J.; Krupka, Kenneth M.; Lindberg, Michael J.; Cantrell, Kirk J.; Brown, Christopher F.; Schaef, Herbert T.

doi:10.2172/908201

Cited by 16 publications

(44 citation statements)

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“…It is possible that the Ni phase occurs as a separate phase sometimes coating the iron oxide. It is also noteworthy that for sample locations that were identified as containing U-Na-O phase(s), the morphology of these particles is very similar to čejkaite which were identified in unleached tank C-203 preretrieval waste (Deutsch et al 2007b). The čejkaite in the unleached tank C-203 preretrieval waste was identifiable by XRD because of its much higher concentrations in this sample.…”

Section: 43supporting

confidence: 52%

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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Section: 43supporting

confidence: 52%

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

Cantrell¹,

Krupka²,

Geiszler³

et al. 2010

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“…This is the first report from this PNNL project to describe the composition and leach test data for residual waste from a salt-cake tank. All previous PNNL reports (Cantrell et al 2008;Deutsch et al 2006Deutsch et al , 2007aDeutsch et al , 2007bDeutsch et al , 2007c describing contaminant release models, and characterization and testing results for residual waste in SSTs were based on samples from sludge tanks.…”

Section: Discussionmentioning

confidence: 99%

Hanford Tank 241-S-112 Residual Waste Composition and Leach Test Data

Cantrell¹,

Krupka²,

Geiszler³

et al. 2008

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SummaryAs directed by Congress, the U.S. Department of Energy (DOE) established the Office of River Protection in 1998 to manage DOE's largest, most complex environmental cleanup project -retrieval of radioactive waste from Hanford Site tanks for treatment and eventual disposal. Sixty percent by volume of the nation's high-level radioactive waste is stored at the Hanford Site in aging, deteriorating tanks. If not cleaned up, this waste is a threat to the nearby Columbia River and the Pacific Northwest.CH2M HILL Hanford Group, Inc. is the DOE Office of River Protection's prime contractor responsible for the storage, retrieval, and disposal of Hanford Site tank waste. As part of this effort, CH2M HILL Hanford Group, Inc. contracted with Pacific Northwest National Laboratory (PNNL) to conduct testing for selected key contaminants present in residual waste remaining in the single-shell tank 241-S-112 (S-112).This report presents the results of laboratory characterization, testing, and analysis of two samples (designated 20406 and 20407) of residual waste collected from tank S-112 after final waste retrieval. These studies were completed to characterize the residual waste and assess the leachability of contaminants from the solids. This is the first report from this PNNL project to describe the composition and leach test data for residual waste from a salt cake tank. All previous PNNL reports describing contaminant release models, and characterization and testing results for residual waste in single-shell tanks were based on samples from sludge tanks. iv important component of this encrustation. The SEM/EDS analysis also revealed the presence of Fe oxides, a Ca-Cr-O phase, a Pb-Cl±O phase, and possibly one or more silicate phases, but particles with these compositions were very rare in the tank S-112 residual waste.Results of the Tier 1 analysis of the bulk composition of tank S-112 samples indicate that Al is the largest, single metal component of the waste (7.1 to 8.4 wt% for the two samples). Other major metal components (Na, Fe, Cr, and Si) occurred at lower concentrations, ranging from 4.7 to 5.2%, 0.21 to 0.24%, 0.17 to 0.18%, and 0.10 to 0.14%, respectively, for the two samples. Based on these results and assuming Al occurs primarily as gibbsite, this Al phase would account for 21 to 24 wt% of the residual waste. The residual waste compositions determined in this study were generally consistent with those determined by the 222-S Laboratory, except for the concentrations determined for Al. 3 dilution (Le Chatelier's principle). For Ca, researchers determined that nearly all Ca in the extracts cameThe average Al concentration determined from the 222-S Laboratory results was 29.1 wt% (dry wt basis). If all Al occurred as gibbsite, this would account for 84% of the mass of the residual waste. This result is more consistent with PNNL's XRD and SEM/EDS results compared to those from the bulk composition analyses. Based on these comparisons, PNNL's Al concentrations for the unleached (as received) bulk solid appear t...

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“…Studies of the C-203 and C-204 preretrieval wastes by Deutsch et al (2004) did not include at that time the Ca(OH) 2 and CaCO 3 leach measurements used in our current testing methodology. Characterization studies of pre-retrieval wastes from tanks C-203 and C-204 identified the presence of čejkaite [Na 4 (UO 2 )(CO 3 ) 3 ] as the primary crystalline phase and the possible presence of nitratine (NaNO 3 ) in the unleached (as-received) C-203 and C-204 pre-retrieval wastes Krupka et al 2006).…”

Section: Comparison Of Sem/eds Results For Residual (Post Retrieval) mentioning

confidence: 99%

“…A synchrotron focused x-ray beam was used to collect transmission µXRD patterns on several ~5-µm diameter areas of relatively large (approximately 20 to 100 μm) U-and Fe-rich particles identified by microscanning x-ray fluorescence (µSXRF) in the sample of C-203 pre-retrieval waste. Although Deutsch et al (2004) did not identify goethite or maghemite in their bulk XRD analyses of this same C-203 pre-retrieval sludge, they did determine the presence of Fe oxides by SEM/EDS. Similarly, the bulk XRD analyses of the post-retrieval (residual) sludge from tanks C-202 and C-203 did not indicate the presence of any crystalline Fe oxide phases.…”

Section: C-203 Post-retrieval Residual Sludgementioning

confidence: 95%

“…Some of these cavities (see red arrows in micrograph A in Figure 3.11) also suggest that the dissolved phase might have been rod shaped. The cross sections of these dissolution pits are reminiscent of the hexagonal-like cross sections of the acicular crystals of čejkaite [Na 4 (UO 2 )(CO 3 ) 3 ] (see insert from Deutsch et al [2004] in micrograph B in Figure 3.11) identified in unleached C-203 and C-204 pre-retrieval waste sludge. Because these hexagonal-like dissolution pits were identified in samples of unleached C-203 residual sludge, it is assumed that they exist in the actual residual waste still in the C-200 series tanks.…”

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confidence: 97%

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Hanford Tanks 241-C-202 and 241-C-203 Residual Waste Contaminant Release Models and Supporting Data

Deutsch¹,

Krupka²,

Lindberg³

et al. 2007

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SummaryAs directed by Congress, the U.S. Department of Energy (DOE) established the Office of River Protection in 1998 to manage DOE's largest, most complex environmental cleanup project -retrieval of radioactive waste from Hanford tanks for treatment and eventual disposal. Sixty percent by volume of the nation's high-level radioactive waste is stored at Hanford in aging deteriorating tanks. If not cleaned up, this waste is a threat to the Columbia River and the Pacific Northwest.CH2M HILL Hanford Group, Inc. is the Office of River Protection's prime contractor responsible for the storage, retrieval, and disposal of Hanford's tank waste. As part of this effort, CH2M HILL Hanford Group, Inc. contracted with Pacific Northwest National Laboratory (PNNL) to develop release models for key contaminants that are present in residual sludge remaining in Hanford Tanks 241-C-202 (C-202) and 241-C-203 (C-203). The release models were developed from data generated by laboratory characterization and testing of samples from these two tanks. These release models are being developed to support the tank risk assessments performed by CH2M HILL Hanford Group, Inc. for DOE.The contaminant release models developed for these tanks are based on empirical solubility release models. Sludge testing was not successful in identifying minerals in the solids that may be limiting contaminant release; thus, it was not possible to develop mechanistic release models for the residual sludge in these tanks. The empirical release models apply to two different tank scenarios. In the first scenario the tank is filled with a relatively inert material, such as sand, and the leaching solution that contacts sludge in the future is in equilibrium with calcite (CaCO 3 ). Equilibrium with calcite is the typical condition for Hanford vadose zone porewater and groundwater, and Ca 2+ and CO 3 2-/HCO 3 -are the common major cation and anions in solution. Alternatively, the tanks might be filled with a cementitious material, which would produce a Ca(OH) 2 dominated leaching solution while the cement is fresh. As the cement reacts with infiltrating water and ages, it would evolve to resemble the CaCO 3 solution of the first scenario. Empirical solubility release models for the primary contaminants of interest (U, Cr, and 99 Tc) have been developed from laboratory leaching tests of sludge samples using the Ca(OH) 2 and CaCO 3 leaching solutions. Results for 129 I results were below the detection limit.Key results from this work are that future release concentrations from these tanks of the primary contaminants of concern in most cases represent less than 10% of the total contaminant concentration in the sludge. That is, the contaminants are not appreciably soluble in the Ca(OH) 2 and CaCO 3 leaching solutions. For example, the cumulative amount of U leached by the Ca(OH) 2 leaching solution during six sequential stages of leaching represented only 0.13% and 0.11% of the total uranium in tanks C-202 and C-203, respectively. The corresponding percentages of U leached...

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

Cited by 16 publications

References 1 publication

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

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

Hanford Tank 241-S-112 Residual Waste Composition and Leach Test Data

Hanford Tanks 241-C-202 and 241-C-203 Residual Waste Contaminant Release Models and Supporting Data

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