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Title: 1/6TH SCALE STRIP EFFLUENT FEED TANK-MIXING RESULTS USING MCU SOLVENT

Abstract

The purpose of this task was to determine if mixing was an issue for the entrainment and dispersion of the Modular Caustic Side Solvent Extraction (CSSX) Unit (MCU) solvent in the Defense Waste Processing Facility (DWPF) Strip Effluent Feed Tank (SEFT). The MCU strip effluent stream containing the Cs removed during salt processing will be transferred to the DWPF for immobilization in HLW glass. In lab-scale DWPF chemical process cell testing, mixing of the solvent in the dilute nitric acid solution proved problematic, and the Savannah River National Laboratory (SRNL) was requested to perform scaled SEFT mixing tests to evaluate whether the problem was symptomatic of the lab-scale set-up or of the solvent. The solvent levels tested were 228 and 235 ppm, which represented levels near the estimated DWPF solvent limit of 239 ppm in 0.001M HNO{sub 3} solution. The 239 ppm limit was calculated by Norato in X-CLC-S-00141. The general approach for the mixing investigation was to: (1) Investigate the use of fluorescent dyes to aid in observing the mixing behavior. Evaluate and compare the physical properties of the fluorescent dyed MCU solvents to the baseline Oak Ridge CSSX solvent. Based on the data, use the dyed MCU solventmore » that best approximates the physical properties. (2) Use approximately a 1/6th linear scale of the SEFT to replicate the internal configuration for DWPF mixing. (3) Determine agitator speed(s) for scaled testing based on the DWPF SEFT mixing speed. (4) Perform mixing tests using the 1/6th SEFT and determine any mixing issues (entrainment/dispersion, accumulation, adhesion) through visual observations and by pulling samples to assess uniformity. The mixing tests used MCU solvent fabricated at SRNL blended with Risk Reactor DFSB-K43 fluorescent dye. This dyed SRNL MCU solvent had equivalent physical properties important to mixing as compared to the Oak Ridge baseline solvent, blended easily with the MCU solvent, and provided an excellent visual aid.« less

Authors:
Publication Date:
Research Org.:
SRS
Sponsoring Org.:
USDOE
OSTI Identifier:
890206
Report Number(s):
WSRC-TR-2005-00552R0
TRN: US0604617
DOE Contract Number:
DE-AC09-96SR18500
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; TANKS; RADIOACTIVE WASTE PROCESSING; CESIUM 137; ENTRAINMENT; PHYSICAL PROPERTIES; SOLVENT EXTRACTION; SOLVENTS; TESTING; MIXING; SUSPENSIONS

Citation Formats

Hansen, E. 1/6TH SCALE STRIP EFFLUENT FEED TANK-MIXING RESULTS USING MCU SOLVENT. United States: N. p., 2006. Web. doi:10.2172/890206.
Hansen, E. 1/6TH SCALE STRIP EFFLUENT FEED TANK-MIXING RESULTS USING MCU SOLVENT. United States. doi:10.2172/890206.
Hansen, E. Wed . "1/6TH SCALE STRIP EFFLUENT FEED TANK-MIXING RESULTS USING MCU SOLVENT". United States. doi:10.2172/890206. https://www.osti.gov/servlets/purl/890206.
@article{osti_890206,
title = {1/6TH SCALE STRIP EFFLUENT FEED TANK-MIXING RESULTS USING MCU SOLVENT},
author = {Hansen, E},
abstractNote = {The purpose of this task was to determine if mixing was an issue for the entrainment and dispersion of the Modular Caustic Side Solvent Extraction (CSSX) Unit (MCU) solvent in the Defense Waste Processing Facility (DWPF) Strip Effluent Feed Tank (SEFT). The MCU strip effluent stream containing the Cs removed during salt processing will be transferred to the DWPF for immobilization in HLW glass. In lab-scale DWPF chemical process cell testing, mixing of the solvent in the dilute nitric acid solution proved problematic, and the Savannah River National Laboratory (SRNL) was requested to perform scaled SEFT mixing tests to evaluate whether the problem was symptomatic of the lab-scale set-up or of the solvent. The solvent levels tested were 228 and 235 ppm, which represented levels near the estimated DWPF solvent limit of 239 ppm in 0.001M HNO{sub 3} solution. The 239 ppm limit was calculated by Norato in X-CLC-S-00141. The general approach for the mixing investigation was to: (1) Investigate the use of fluorescent dyes to aid in observing the mixing behavior. Evaluate and compare the physical properties of the fluorescent dyed MCU solvents to the baseline Oak Ridge CSSX solvent. Based on the data, use the dyed MCU solvent that best approximates the physical properties. (2) Use approximately a 1/6th linear scale of the SEFT to replicate the internal configuration for DWPF mixing. (3) Determine agitator speed(s) for scaled testing based on the DWPF SEFT mixing speed. (4) Perform mixing tests using the 1/6th SEFT and determine any mixing issues (entrainment/dispersion, accumulation, adhesion) through visual observations and by pulling samples to assess uniformity. The mixing tests used MCU solvent fabricated at SRNL blended with Risk Reactor DFSB-K43 fluorescent dye. This dyed SRNL MCU solvent had equivalent physical properties important to mixing as compared to the Oak Ridge baseline solvent, blended easily with the MCU solvent, and provided an excellent visual aid.},
doi = {10.2172/890206},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Feb 01 00:00:00 EST 2006},
month = {Wed Feb 01 00:00:00 EST 2006}
}

Technical Report:

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  • The Savannah River National Laboratory (SRNL) was tasked with preparing and shipping samples for Hg speciation by Eurofins Frontier Global Sciences, Inc. in Seattle, WA on behalf of the Savannah River Remediation (SRR) Mercury Task Team.i,ii The tenth shipment of samples was designated to include Modular Caustic Side Solvent Extraction Unit (MCU) Strip Effluent Hold Tank (SEHT) and MCU Decontaminated Salt Solution Hold Tank (DSSHT) materials from processing Salt Batch 7b. The MCU SEHT (MCU-15-722) and DSSHT (MCU-15-709) samples were pulled on June 15, 2015. All MCU samples were received at SRNL on June 16, 2015. The DSSHT sample wasmore » moved the same day to refrigeration, while the SEHT sample was placed in the Shielded Cells. On July 9, 2015 it was opened and an aliquot diluted 1:100 with Eurofins deionized water and a portion of the diluted sample transferred to a Teflon® bottle prior to moving it to refrigeration that same day. All samples were kept in the dark and refrigerated until final dilutions were prepared for shipment to Eurofins.« less
  • Savannah River National Laboratory (SRNL) analyzed solvent samples from Modular Caustic-Side Solvent Extraction Unit (MCU) in support of continuing operations. A quarterly analysis of the solvent is required to maintain solvent composition within specifications. Analytical results of the analyses of Solvent Hold Tank (SHT) samples MCU-11-314, MCU-11-315, MCU-11-316, MCU-11-317, MCU-11-318 and MCU-11-319 are reported. The results show that the solvent at MCU does not require an Isopar{reg_sign} L addition, but it will require addition of trioctylamine. Cesium mass transfer testing with the solvent matches expected extraction behavior but shows a slightly lower stripping efficiency than seen in the original processmore » demonstration for Macrobatch 3. The entrained aqueous solution indicates the scrub wash is significantly out of specification. As a result, the facility replaced the scrub wash. Unlike the previous solvent sample results, these analyses indicate that the solvent does not require minor Isopar{reg_sign} L trimming at this time. However, addition of TOA is warranted. These findings indicate that the new protocols for solvent monitoring and control are yielding favorable results. Nevertheless, the deviation in the TOA concentration since the last analysis indicates continued periodic (i.e., quarterly) monitoring is recommended. The {sup 137}Cs mass transfer results from the solvent sample testing show possible evidence of slightly reduced stripping efficiency. An evaluation (using a model) of expected system performance for MCU using the measured distribution values predicts an {approx}50% decline in DFs given the ESS test results. The customer should consider pulling a SHT sample for reanalysis.« less
  • Solvent Hold Tank (SHT) samples are sent to Savannah River National Laboratory (SRNL) to examine solvent composition changes over time. On December 5, 2011, Operations personnel delivered six samples from the SHT (MCU-11-1452 through -1457) for analysis. These samples are intended to verify that the solvent is within the specified composition range. The results from the analyses are presented in this document. Samples were received in p-nut vials containing {approx}10 mL each. Once taken into the Shielded Cells, the samples were combined. Samples were removed for analysis by density, semi-volatile organic analysis (SVOA), high performance liquid chromatography (HPLC), and Fourier-Transformmore » Infra-Red spectroscopy (FTIR). Details for the work are contained in a controlled laboratory notebook. Each of the six p-nut vials contained a single phase, with no apparent solids contamination or cloudiness. Table 1 contains the results of the analyses for the combined samples. A duplicate density measurement of the organic phase gave a result of 0.844 g/mL (1.2% residual standard deviation - RSD). Using the density as a starting point, we know that the Isopar{reg_sign} L should be slightly higher than nominal and the other components should be slightly lower than nominal. The results as a whole are internally consistent. All measurements indicate Isopar{reg_sign} L higher than nominal, and Modifier lower than nominal. The extractant result is higher than expected - given the other results, the extractant concentration should be under nominal values. Using the measured density as well as the Isopar{reg_sign} L and Modifier concentrations from the FTIR results, we calculate an extractant concentration of 6888 mg/L. This value is outside the analytical uncertainty of the reported HPLC value. Given the other results, this most likely indicates that the HPLC extractant result was biased high. When compared to the MCU density target of 0.845 g/mL, there is no need to add an Isopar{reg_sign} L trim. However, it is advisable to add sufficient trioctylamine (TOA) to return the solvent composition to within specifications as that component has declined to about 64% the concentration since the last analysis. The TOA measurement was performed twice, so the result is not an analytical aberration. TOA has not been added to the system since the previous quarterly sample in October 2011. As with the previous solvent sample results, these analyses indicate that the solvent does not require Isopar{reg_sign} L trimming at this time. However, addition of TOA is warranted. These findings indicate that the new protocols for solvent monitoring and control are yielding favorable results. Nevertheless, the deviation in the TOA concentration since the last analysis indicates continued periodic (i.e., quarterly) monitoring is recommended.« less
  • Savannah River National Laboratory (SRNL) analyzed solvent samples from Modular Caustic-Side Solvent Extraction Unit (MCU) in support of continuing operations. A quarterly analysis of the solvent is required to maintain solvent composition within specifications. Analytical results of the analyses of Solvent Hold Tank (SHT) samples MCU-12-488, MCU-12-489, MCU-12-490, MCU-12-491, MCU-12-492 and MCU-12-493 received 24 October 2012 are reported. The results show that the solvent at MCU does not require an Isopar® L addition, but it will require addition of trioctylamine. SRNL also analyzed the SHT sample for {sup 137}Cs content and determined the measured value is within tolerance but ismore » trending upward compared to the {sup 137}Cs measurement made last year.« less
  • Savannah River National Laboratory (SRNL) analyzed solvent samples from Modular Caustic-Side Solvent Extraction Unit (MCU) in support of continuing operations. A quarterly analysis of the solvent is required to maintain solvent composition within specifications. Analytical results of the analyses of Solvent Hold Tank (SHT) samples MCU-13-143, MCU-13-144, MCU-13-145, MCU-13-146, MCU-13-147 and MCU-13-148 received 29 January 2012 are reported. The results show that the solvent at MCU does not require an Isopar® L addition, but it will require addition of trioctylamine. SRNL also analyzed the SHT sample for {sup 137}Cs content and determined the measured value is within tolerance and themore » value has returned to levels observed in 2012.« less