Engineering topics

Woodham, Wesley H.

Publications and source records attributed to Woodham, Wesley H..

18 records

DOE OSTI2024

Investigation of Mercury Compound Partitioning Through the Solvent Extraction System

Savannah River National Laboratory (SRNL) has been requested by Savannah River Mission Completion (SRMC)/ Salt Waste Processing Facility (SWPF) personnel to investigate the potential routes for titanium and mercury accumulations within the SWPF Flowsheet. This report documents work performed to examine how various forms of mercury can migrate through the multiple flowsheets of a solvent extraction system. This entailed 29 single stage distribution tests, a multi-stage Extraction-Scrub-Strip (ESS) test, and a detailed speciation analysis of several salt batch feed samples.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2023

Investigation of Methane Generation Rates from Simulated and Radioactive Waste at Evaporator Conditions

Savannah River National Laboratory researchers have performed 9 experiments with simulated waste and 13 experiments with radioactive waste to determine methane generation rates (MGR) applicable to Savannah River Site waste at temperatures greater than or equal to 100 °C. Data from these experiments was used to generate temperature-dependent expressions to conservatively account for methane generation at elevated temperatures. Measured MGRs and the derived expressions are reported in units of standard cubic feet per hour per gallon of solution, where standard conditions are 25 °C and 1 atm.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2023

Analysis of Solids Obtained from 201O, 201P, 202A, and 202B Contactors in the Salt Waste Processing Facility

In December 2022, Savannah River Mission Completion personnel recovered solids samples from four contractors (EXT-001, EXT-007, EXT-031, and EXT-040) employed at the Salt Waste Processing Facility (SWPF). These solids were submitted to Savannah River National Laboratory for analysis and characterization. This Technical Report outlines the analytical findings and observations associated with these samples and explores the potential source of solid generation within the SWPF. The following conclusions are offered as a result of this work: the light color solids recovered from EXT-007 are consistent with crystallized, soluble salt components (such as sodium nitrate, sodium hydroxide, and sodium carbonate), all of which can be easily re-dissolved in process water and do not represent a threat to SWPF CSSX processing. While the light solids from the top of EXT-040 were not analyzed, it is believed that they share similar characteristics to those recovered from EXT-007; The dark color solids recovered from EXT-001, EXT-031, and the inside of EXT-040 appear to be complex, consisting of several different types of solids: High concentrations of mercury (Hg, 40-75% by mass) partially present as elemental Hg are consistent with the precipitation of Hg 0 /Hg 2+ from disproportionation of Hg + species in pH swing conditions; Moderate concentrations of titanium (Ti) (2-7%, by mass) are also present, often co-located with Hg. This is consistent with co-precipitation, entrainment, and/or amalgamation of Ti and Hg; Moderate concentrations of iron (Fe) (1-3%, by mass) are observed in SWPF solids and are likely attributable to erosion of stainless-steel components within the CSSX process; Small concentrations of tungsten (W) and cobalt (Co) (<1%, by mass) are observed in SWPF solids. The presence of these solids is consistent with the erosion of components coated with W and Co (e.g., Stellite); Small concentrations of aluminum (Al) (<1%, by mass) are observed in the form of gibbsite and potentially sodium aluminosilicate. The presence of these compounds is likely attributable to the pH swing observed between the scrub and extraction cycles within the CSSX process. The following recommendations are made as a result of this work: Testing should be performed to determine the chemical drivers, process, and mechanism of Hg precipitation in CSSX processing. Special care should be taken to include titanium in tests to evaluate the potential for co-precipitation, entrainment, and amalgamation; Hg-mitigation options that would minimize or eliminate risks of Hg precipitation and solids accumulation (e.g., Hg-absorption techniques, ion exchange/adsorbents, flowsheet changes, etc.) should be assessed.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2022

Impacts of Guanidine Degradation Products on Next Generation Solvent (NGS) Caustic Side Solvent Extraction (CSSX) Processing

Savannah River National Laboratory researchers have been requested to perform testing to assess the potential for build-up of guanidine degradation compounds in the Next Generation Solvent Caustic Side Solvent Extraction process. Testing was also requested to determine the impact of guanidine degradation compounds [3,7-dimethyloctylamine (iDA) and Bis-N,N’-(3,7-dimethyloctyl)urea (DiDU)] on cesium behavior in the flowsheet. Twelve partitioning experiments were performed to quantify the partitioning coefficient of identified guanidine degradation compounds in various organic-aqueous mixtures. Six Extraction, Scrub, and Strip (ESS) experiments were performed to quantify the impact of degradation products on cesium behavior.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2022

Organomercury Measurements from Sludge Batch 10 Simulant Studies

Researchers at the Savannah River National Laboratory have recently performed testing to evaluate the Sludge Batch 10 flowsheet using simulated sludge waste. In the course of this testing several samples were taken to determine the concentration of organomercury species resulting from sludge batch processing. These samples were submitted to the Savannah River National Laboratory Sensing and Metrology department quantitation using a mercury analyzer. The signal amplifier used to perform organomercury quantitation in the mercury analyzer experienced a malfunction in the course of analysis, leading to uncertainty of organomercury concentrations observed. Seventy-three organomercury samples from six project submissions to the Savannah River National Laboratory Sensing and Metrology department have been critically reviewed.

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DOE OSTI2022

Evaluation of Sludge Solids Returns Impacts on Sludge Batch 10 Flammability, Glass Quality, and Glass Processability

The Savannah River National Laboratory (SRNL) is currently preparing to return ≤ 20 kgs of sludge solids collected over time from Tank Farm characterization activities and demonstrations of the Defense Waste Processing Facility (DWPF) flowsheets (nitric-formic and nitric-glycolic). These sludge solids will be transported and added to Tank 51 which is currently preparing Sludge Batch (SB) 10. DWPF plans to operate the under the nitric-glycolic flowsheet for the processing of SB10. The hydrogen generation rate for the nitric-glycolic flowsheet is 0.024 lb h -1 . The addition of ≤20 kg of sludge solids returns to SB 10 does not have an impact on flammability in the DWPF Chemical Process Cell (CPC) or glass quality and processability. The relatively low mass of the addition (≤20 kg) is insufficient to detect a significant analytical change to the expected SB 10 compositions.

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DOE OSTI2021

Sludge Batch 10 Flowsheet Testing with Non-radioactive Simulants

Fourteen Chemical Processing Cell (CPC) simulations were performed with nonradioactive sludge simulants at the Aiken County Technology Laboratory in Aiken, SC. Four of these experiments were performed with Tank 51 sludge simulant. The remaining ten were performed with Tank 40 sludge simulant. The purpose of these experiments was to elucidate the chemistry and characteristics of Sludge Batch (SB) 10 as anticipated in the Defense Waste Processing Facility (DWPF). Experiments were performed at acid stoichiometries between 76% and 138% of the Koopman Minimum Acid requirement (85% - 144% of the Hsu acid requirement) and at REDuction/OXidation (REDOX) targets between 0.1 and 0.3. Testing examined the impact of coupled operations and sludge-only operations during Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) processing at both design basis and nominal boilup rates. This report shares conclusions made as a result of this testing.

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DOE OSTI2021

Investigation of Thermolytic Hydrogen Generation Rate in Tank 44 Dissolved Saltcake Samples

Saltcake core samples collected from Tank 44 in 2006 were dissolved to provide material for HGR measurements applicable to F-Area dissolved saltcake material. Additionally, characterization was performed on the Tank 44 saltcake material. The following are key results from the Tank 44 saltcake characterization. The Tank 44 Upper Saltcake Composite, corresponding to the 171 to 285 inch tank level, contained by mass approximately 69% sodium nitrate, 11% sodium carbonate, 8% sodium nitrite, smaller amounts of other salts and components, and 9% unquantified (which includes water, water of hydration, oxygen/hydrogen content of oxides and hydroxides, and uncertainty). The Tank 44 Lower Saltcake Composite, corresponding to the 76 to 114 inch tank level, contained by mass approximately 49% sodium carbonate, 18% sodium nitrate, smaller amounts of other salts, at least 8% sludge, and 9% unquantified (see above). The dissolved saltcake contained free hydroxide less than quantifiable (<0.01 M) due to the limited quantity of material that could be removed from the Shielded Cells based on the sample radioactivity. Measurement by pH paper provided an approximate pH of 12. The following are key results from the Tank 44 HGR testing. During boiling at 106.7 °C, HGR for Tank 44 dissolved saltcake without added glycolate was 7.2×10 -8 ft 3 h -1 gal -1 . During boiling at 106.9 °C, HGR for Tank 44 dissolved saltcake with 1000 mg/L of added glycolate was 8.2×10 -8 ft 3 h -1 gal -1 . For the test without added glycolate, the first several HGR measurements at 70, 85, and 100 °C gave indication of the release of dissolved hydrogen and should not be used to represent the sustained thermolytic HGR for those temperatures. The measurements at boiling are the best representation of thermolysis in this testing. Carbon dioxide was observed at concentrations up to 6 vol% in the flow-system offgas for the test at boiling. Methane generation was observed at 100 °C and boiling. Methane concentration in the total gas generated during testing remained well below the lower flammability limit for methane in air. The addition of 1000 mg/L of glycolate did not have a significant impact on the hydrogen generation rates measured during this testing. The low hydroxide concentration in the Tank 44 dissolved saltcake likely influenced the relatively low thermolytic HGR and high carbon dioxide release observations in this testing. Based on the observation that methane was generated or released upon heating SRS radioactive Tank 44 waste samples to 100 °C and above, we recommend gaining a greater understanding of the cause and mechanism of its generation. First, the applicable literature should be reviewed to reveal the thermolytic methane generation mechanisms of possible methane generating species in the SRS CSTF. If warranted, a plan should be developed for simulant tests with methylated siloxanes and other applicable compounds in order to gain a better mechanistic understanding of methane generation in the SRS CSTF.

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DOE OSTI2021

Antifoam Development for Eliminating Flammability Hazards and Decreasing Cycle Time in the Defense Waste Processing Facility

Foam, due to the high gas generation rates of boiling and chemical reaction offgasing, requires control measures to prevent the foam from contaminating the condensate and to facilitate efficient plant operation. Antifoam was utilized to minimize foam production during chemical processing in the DWPF and during High-Level Waste (HLW) evaporation at SRS and Hanford. However, the current antifoam used in the SRS DWPF increases flammability risk during chemical processing (generates three flammable degradation products) and while feeding the melter (can decompose to CO/hydrogen). It is also the likely source of methyl functional groups for the organo-mercury present in the tank farm and excessive mercury in Saltstone. Additionally, the planned startup of Salt Waste Processing Facility (SWPF), with much higher throughput, will challenge DWPF to process at higher gas generation rates. DWPF employs Antifoam 747, a superspreader produced by Momentive Performance Materials, as an antifoaming agent during waste processing. During DWPF chemical processing, antifoam must be effective up to boiling (i.e., up to 103°C) and between a pH of 3-13. Antifoam 747 is most effective at a pH range of 6-8 and degrades as pH deviates. In addition, SRNL identified three flammable antifoam degradation products using mass spectrometer (MS) and fourier transform infrared (FTIR) offgas analyzers during simulations. A new antifoam or a new method to control foam is needed to minimize DWPF processing time and reduce the risk of contamination. In addition, testing should be completed to ensure that other antifoams used in HLW processing do not have similar flammability hazards or cause unintended impacts in downstream processing.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2021

Antifoam Development for Eliminating Flammability Hazards and Decreasing Cycle Time in the Defense Waste Processing Facility

The Savannah River National Laboratory (SRNL) was requested to develop a new antifoam control method for the Defense Waste Processing Facility’s (DWPF) Chemical Process Cell (CPC). SRNL completed testing of both chemical and nonchemical foam controls. The nonchemical foam controls were either ineffective (or worse, created more foam) or impractical (i.e., a water spray can control foam, but excessive water is needed). As a result, the focus of this study was on finding a superwetter or commercial antifoam for controlling foam.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2021

A novel defoamer for processing nuclear waste: Testing and performance

Abstract Legacy radioactive waste from nuclear weapons material processing is the biggest environmental challenge in the state of South Carolina, and one of the biggest in the United States. Although substantial progress has been made in processing and vitrifying high‐level radioactive waste at the Savannah River site, approximately 35 million gallons remains to be treated and dispositioned. In this article, we show the development of a new defoamer for use in the processing of high‐level radioactive waste. The application of the new defoamer is not only more effective at controlling foam but will shorten the batch processing time leading to safer and more efficient processing. This has the potential to help shorten the overall site mission lifetime, saving the federal government hundreds of millions of dollars. The novel aspect of the new defoamer is its effectiveness and stability in the harsh conditions needed for processing high‐level radioactive waste: high temperatures, pH 4–13, strong oxidizing and reducing agents, and numerous metal catalysts. The defoamer will replace an existing antifoam agent that decomposes to form multiple flammable gases. Because the existing antifoam agent decomposes quickly, processing changes increased processing time. Statement of novelty We demonstrate that a new defoamer has been developed for use in processing high‐level radioactive waste. This novel defoamer is effective and stable in the harsh processing conditions with no detectable flammable by‐products. Because the existing antifoam agent decomposes quickly, processing changes, including lowering acid addition rates and evaporation rates, increased processing time. The new defoamer is not only more effective at controlling foam but will shorten the batch processing time and lead to safer and more efficient processing by eliminating the production of flammable gases. Statement of industrial relevance Foaming is of great concern in many industrial processes involving three‐phase gas/liquid/fine‐solids systems, like in water evaporation, mineral floatation, air sparging in situ remediation techniques, and in those found in the paper industry.

Lambert, Dan P.↗

DOE OSTI2021

Antifoam Development for Eliminating Flammability Hazards and Decreasing Cycle Time in the Defense Waste Processing Facility

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DOE OSTI2020

Thermodynamics of Deuterium Oxide Separations in Aqueous Two-Phase Systems

The thermodynamic behavior of aqueousorgame- toluene ternary systems where aqueous components are water (H 2 O) and deuterium oxide (D 2 O) and organic components are acetonitrile (MeCN), tetrahydrofuran (THF), and 1,4-dioxane (DIOX) have been recorded. Preliminary data has been taken for each ternary system to establish the concentration along the spinodal line where Gibbs energy is minimized. In pursuit of this goal, simple laboratory techniques using common equipment was used to benchmark thermodynamic measurements against values reported in the literature. The impact of deuterium on aqueous two-phase separations was determined for each combination of solvents.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Calculation of Glycolate Concentration Factors Across the 242-25H (3H) Evaporator System

Two models were developed to predict glycolate concentration factors across the 242-25H (3H) Evaporator system. The first model, identified as the Unrestricted Evaporation Model, was designed to evaluate concentration of typical 3H feed material to relatively high densities in order to calculate the concentration factor of glycolate in a given feed stream. This model may be used to understand the potential of glycolate to concentrate from a generic feed material through the 3H system. The second model, identified as the Holistic Evaporation Model, was designed to evaluate the evaporation of dilute, glycolate-containing Defense Waste Processing Facility (DWPF) waste with the requirement that high silicon concentrations typical of recycle material require dilution to adhere to current technical safety requirements. This model may be used to understand the potential of glycolate from DWPF recycle material to concentrate as a result of feeding through the 3H system.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2020

Modeling the Destruction of Glycolate in the Defense Waste Processing Facility (DWPF) Recycle Stream and Concentration Factors for Glycolate in the 2H Evaporator

Two models were developed to predict maximum glycolate concentrations in the Savannah River Site (SRS) Concentration, Storage, and Transfer Facility (CSTF) from implementation of the Nitric-Glycolic flowsheet at the Defense Waste Processing Facility (DWPF). One model describes the kinetics of glycolate destruction via chemical oxidation with sodium permanganate. This model conservatively predicts glycolate concentration delivered to the CSTF with a high probability the actual glycolate concentration is lower than predicted. The second model describes the potential concentration of said residual glycolate within the 242-16H (i.e., “2H”) Evaporator system.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2020

Antifoam Development for Eliminating Flammability Hazards and Decreasing Cycle Time in the Defense Waste Processing Facility

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2020

Radiolytic and Thermolytic Bubble Gas Hydrogen Composition

The original version of this report described the development of a mathematical model for the estimation of the hydrogen composition of gas bubbles trapped in radioactive waste. The model described therein used a material balance approach to accurately incorporate the rates of hydrogen generation by several physical phenomena and scale the aforementioned rates in a manner that allows calculation of the final hydrogen composition. The proposed model accounted for the following physical phenomena: H 2 generation by primary radiolysis of water and salt solutions; H 2 generation by secondary radiolysis of formate and glycolate molecules in solution; Observation of negligible H 2 generation by thermolysis of formate at temperatures below 120 °C; H 2 generation by thermolysis of glycolate in caustic solutions; O 2 consumption by radiolysis and thermolysis of organic species. Additionally, the originally-proposed model conservatively excluded the following physical phenomena that are known to contribute slightly to the hydrogen composition in trapped gas bubbles: Equilibrium concentration of water vapor in trapped gas bubbles; Generation of N 2 O during radiolysis of nitrite solutions; Incomplete consumption of O 2 by organics. In this revision, the methodology for glycolate thermolysis has been improved to agree with recent findings published by Woodham and Martino. Furthermore, considerations for the thermolysis of organics other than glycolate have been made. In the case of non-glycolate organics, no evidence of non-flammable gas formation exists. Therefore, non-glycolate thermolysis is considered additive for conservatism.

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DOE OSTI2020

Evaluation of Thermolytic Hydrogen Generation Rate Models at High-Temperature/High-Hydroxide Regimes

This report describes the results of testing performed to extend the applicable ranges of temperature and hydroxide concentration for use within the Glycolate and Global Total Organic Carbon (TOC) Hydrogen Generation Rate (HGR) expressions. Seven experimental conditions (six simulants of the 242-25H Evaporator system chosen as a D-optimal set of experiments and a single test conducted at an elevated boiling point of 170 °C) were investigated in the presence of sodium glycolate and Xiameter TM AFE-1010. Glycolate was employed to study the extension of the Glycolate Thermolytic HGR expression while Xiameter TM AFE-1010 was employed to study the extension of the Global TOC Thermolytic HGR expression. The following conclusions were derived from this testing: The Glycolate Thermolytic HGR expression may be confidently used to predict thermolytic HGRs from glycolate at temperatures as high as 170 °C and hydroxide concentrations as high as 23 M.; The hydroxide and temperature-dependence predicted by the Global TOC Thermolytic HGR expression has been confirmed at temperatures as high as 170 °C and hydroxide concentrations as high as 23 M, suggesting that the Global TOC Thermolytic HGR expression may be used at these ranges.; Methane was observed from tests with Xiameter TM AFE-1010 at production rates higher than those observed for hydrogen. These rates were observed at temperatures higher than 100 °C.; Preliminary models suggest that increasing hydroxide/temperature causes an increase in Methane Generation Rate (MGR) from Xiameter TM AFE-1010. The following recommendations are based on this testing: The existing equations for thermolytic HGR from glycolate and non-glycolate organics should be used at Concentration, Storage, and Transfer Facilities (CSTF) storage and evaporation conditions, including temperatures and hydroxide concentrations exhibited in the 242-25H Evaporator.; Further investigation should be made into the influence of methylsilanes on CSTF flammability. This investigation should include: determination of the types of methylsilanes historically added to the CSTF, determination of methane formation rates from each type of methylsilane, and determination of the extent of degradation of methylsilanes in CSTF waste.; Characterization techniques should be developed by Savannah River National Laboratory (SRNL) to assist in the speciation of methylsilane-containing waste in the CSTF.; Additional testing with radioactive waste should be performed to determine the MGRs possible in radioactive waste and better inform model predictions made from testing with simulants.

08 HYDROGEN↗