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Using solvent extraction to process nitrate anion exchange column effluents

Description: Octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO), a new organophosphorous extractant, and a new centrifugal mixer-settler both recently developed at Argonne were evaluated for their potential use in the recovery of actinides from nitrate anion exchange column effluents. The performance of the extractant was evaluated by measuring the extraction coefficient values as a function of acid and salt concentration. Additional performance parameters include extraction coefficient behavior as a function of the total metal concentration in the organic phase, and comparison of different stripping and organic scrubbing techniques. A simulated effluent stream was used to evaluate the performance of the centrifugal mixer-settlers by comparing experimental and calculated interstage concentration profiles. Both the CMPO extractant and the centrifugal mixer-settlers have potential for processing nitrate column effluents, particularly if the stripping behavior can be improved. Details of the proposed process are presented in the flowsheet and contactor design analyses.
Date: October 1, 1987
Creator: Yarbro, S.L.
Partner: UNT Libraries Government Documents Department

Modeling interfacial area transport in multi-fluid systems

Description: Many typical chemical engineering operations are multi-fluid systems. They are carried out in distillation columns (vapor/liquid), liquid-liquid contactors (liquid/liquid) and other similar devices. An important parameter is interfacial area concentration, which determines the rate of interfluid heat, mass and momentum transfer and ultimately, the overall performance of the equipment. In many cases, the models for determining interfacial area concentration are empirical and can only describe the cases for which there is experimental data. In an effort to understand multiphase reactors and the mixing process better, a multi-fluid model has been developed as part of a research effort to calculate interfacial area transport in several different types of in-line static mixers. For this work, the ensemble-averaged property conservation equations have been derived for each fluid and for the mixture. These equations were then combined to derive a transport equation for the interfacial area concentration. The final, one-dimensional model was compared to interfacial area concentration data from two sizes of Kenics in-line mixer, two sizes of concurrent jet and a Tee mixer. In all cases, the calculated and experimental data compared well with the highest scatter being with the Tee mixer comparison.
Date: November 1, 1996
Creator: Yarbro, S.L.
Partner: UNT Libraries Government Documents Department

Comparative evaluation of DHDECMP (dihexyl-N,N-diethylcarbamoyl-methylphosphonate) and CMPO (octylphenyl-N,N,-diisobutylcarbamoylmethylphosphine oxide) as extractants for recovering actinides from nitric acid waste streams

Description: Certain neutral, bifunctional organophosphorous compounds are of special value to the nuclear industry. Dihexyl-N,N-diethylcarbomoylmethylphosphonate (DHDECMP) and octylphenyl-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) are highly selective extractants for removing actinide and lanthanide elements from nitric acid. We obtained these two extractants from newly available commercial sources and evaluated them for recovering Am(III), Pu(IV), and U(VI) from nitric acid waste streams of plutonium processing operations. Variables included the extractant (DHSECMP or CMPO), extractant/tributylphosphate ratio, diluent, nitrate concentration, nitrate salt/nitric acid ratio, fluoride concentration, and contact time. Based on these experimental data, we selected DHDECMP as the perferred extractant for this application. 18 refs., 30 figs.
Date: February 1, 1988
Creator: Marsh, S.F. & Yarbro, S.L.
Partner: UNT Libraries Government Documents Department

The use of safeguards data for process monitoring in the Advanced Test Line for Actinide Separations

Description: Los Alamos is constructing an integrated process monitoring/materials control and accounting (PM/MC and A) system in the Advanced Testing Line for Actinide Separations (ATLAS) at the Los Alamos Plutonium Facility. The ATLAS will test and demonstrate new methods for aqueous processing of plutonium. The ATLAS will also develop, test, and demonstrate the concepts for integrated process monitoring/materials control and accounting. We describe how this integrated PM/MC and A system will function and provide benefits to both process research and materials accounting personnel.
Date: January 1, 1987
Creator: Barnes, J.W. & Yarbro, S.L.
Partner: UNT Libraries Government Documents Department

Near-quantitative recovery of actinides from nitric acid waste streams by solvent extraction using DHDECMP (dihexyl-N,N-diethylcarbamoylmethylphosphonate)

Description: The more-than-adequate extraction of actinides from high nitrate solutions and of efficient back-extraction from low nitrate solutions make DHDECMP the preferred extractant for this application. Isopar-diluted DHDECMP extraction data are presented herein. Comparative extraction data for Am(III) Pu(IV), and U(VI) are also presented. The behavior of these three actinides can be assumed to represent the general behavior of other actinides in their trivalent, tetravalent, and hexavalent oxidation states. 4 refs., 5 figs.
Date: January 1, 1988
Creator: Marsh, S.F. & Yarbro, S.L.
Partner: UNT Libraries Government Documents Department

Optimization of air-sparged plutonium oxalate/hydroxide precipitators

Description: The high cost of waste management and experimental work makes numerical modeling an inexpensive and attractive tool for optimizing and understanding complex chemical processes. Multiphase {open_quotes}bubble{close_quotes} columns are used extensively at the Los Alamos Plutonium Facility for a variety of different applications. No moving parts and efficient mixing characteristics allow them to be used in glovebox operations. Initially, a bubble column for oxalate precipitations is being modeled to identify the effect of various design parameters such as, draft tube location, air sparge rate and vessel geometry. Two-dimensional planar and axisymmetric models have been completed and successfully compared to literature data. Also, a preliminary three-dimensional model has been completed. These results are discussed in this report along with future work.
Date: April 1, 1997
Creator: VanderHeyden, W.B.; Yarbro, S.L. & Fife, K.W.
Partner: UNT Libraries Government Documents Department

Tank SY-102 remediation project summary report: ASPEN modeling

Description: The U.S. Department of Energy established the Tank Waste Remediation System (TWRS) to safely manage and dispose of radioactive waste stored in underground tanks on the Hanford Site. As a part of this program, personnel at Los Alamos National Laboratory (LANL) have developed and demonstrated a flow sheet to remediate tank SY-102, which is located in the 200 West Area and contains high-level radioactive waste. In the conceptual design report issued earlier, an ASPEN plus{trademark} computer model of the flow sheet was presented. This report documents improvements in the flow sheet model after additional thermodynamic data for the actinide species were incorporated.
Date: May 1, 1995
Creator: Punjak, W.A.; Schreiber, S.B. & Yarbro, S.L.
Partner: UNT Libraries Government Documents Department

Technical considerations and policy requirements for plutonium management

Description: The goals for plutonium management have changed dramatically over the past few years. Today, the challenge is focused on isolating plutonium from the environment and preparing it for permanent disposition. In parallel, the requirements for managing plutonium are rapidly changing. For example, there is a significant increase in public awareness on how facilities operate, increased attention to environmental safety and health (ES and H) concerns, greater interest in minimizing waste, more emphasis on protecting material from theft, providing materials for international inspection, and a resurgence of interest in using plutonium as an energy source. Of highest concern, in the immediate future, is protecting plutonium from theft or diversion, while the national policy on disposition is debated. These expanded requirements are causing a broadening of responsibilities within the Department of Energy (DOE) to include at least seven organizations. An unavoidable consequence is the divergence in approach and short-term goals for managing similar materials within each organization. The technology base does exist, properly, safely, and cost effectively to extract plutonium from excess weapons, residues, waste, and contaminated equipment and facilities, and to properly stabilize it. Extracting the plutonium enables it to be easily inventoried, packaged, and managed to minimize the risk of theft and diversion. Discarding excess plutonium does not sufficiently reduce the risk of diversion, and as a result, long-term containment of plutonium from the environment may not be able to be proven to the satisfaction of the public.
Date: December 31, 1995
Creator: Christensen, D.C.; Dinehart, S.M. & Yarbro, S.L.
Partner: UNT Libraries Government Documents Department

Automated homogeneous oxalate precipitation of Pu(III)

Description: Homogeneous oxalate precipitation using diethyl oxalate was compared to precipitating Pu(III) oxalate with solid oxalic acid. The diethyl oxalate technique at 75{degree}C is better because it gives 50% less plutonium in the filtrate with a reasonable filtering time. Also, the procedure for the homogeneous precipitation is easier to automate because the liquid diethyl oxalate is simpler to introduce into the precipitator than solid oxalic acid. It also provides flexibility because the hydrolysis rate and therefore the precipitation rate can be controlled by varying the temperature. 5 refs., 3 figs., 3 tabs.
Date: January 1, 1990
Creator: Yarbro, S.L.; Schreiber, S.B.; Dunn, S.L. & Mills, C.W.
Partner: UNT Libraries Government Documents Department

Evaluation of extractants and chelating resins in polishing actinide-contaminated waste streams

Description: At the Los Alamos National Laboratory Plutonium Facility, anion exchange is used for recovering plutonium from nitric acid solutions. Although this approach recovers >99%, the trace amounts of plutonium and other actinides remaining in the effluent require additional processing. We are doing research to develop a secondary unit operation that can directly polish the effluent so that actinide levels are reduced to below the maximum allowed for facility discharge. We selected solvent extraction, the only unit operation that can meet the stringent process requirements imposed; several carbonyl and phosphoryl extractants were evaluated and their performance characterized. We also investigated various engineering approaches for solvent extraction; the most promising was a chelating resin loaded with extractant. Our research now focuses on the synthesis of malonamides, and our goal is to bond these extractants to a resin matrix. 7 refs., 12 figs., 1 tab.
Date: June 1, 1991
Creator: Schreiber, S.B.; Dunn, S.L. & Yarbro, S.L.
Partner: UNT Libraries Government Documents Department

Comparison between CMPO and DHDECMP for alpha decontamination of radioactive liquid waste

Description: Ion exchange is the major method used at Los Alamos to recover and purify plutonium from a variety of different contaminants. During this process, a high-acid (5-7M), low-activity stream is produced that presently is concentrated by evaporation, then cemented for long-term disposal. Our goal is to remove and concentrate the radioactive elements so that the remainder can be treated as low-level'' or regular industrial waste. Solvent extraction with neutral bifunctional extractants, such as DHDECMP and CMPO, has been chosen as the process to be developed. Experimental work has shown that both extractants effectively remove actinides to below the required limits, but that CMPO was much more difficult to strip. In addition, studies of plutonium and americium removal using a wide variety of ion exchangers and supported extractants including DHDECMP, CMPO, and TOPO will be reviewed. 22 refs., 10 figs., 3 tabs.
Date: January 1, 1990
Creator: Muscatello, A.C.; Yarbro, S.L. & Marsh, S.F.
Partner: UNT Libraries Government Documents Department

Prediction of heat capacities of solid inorganic salts from group contributions

Description: A group contribution technique is proposed to predict the coefficients in the heat capacity correlation, C{sub p} = a + bT + c/T{sup 2} + dT{sup 2}, for solid inorganic salts. The results from this work are compared with fits to experimental data from the literature. It is shown to give good predictions for both simple and complex solid inorganic salts. Literature heat capacities for a large number (664) of solid inorganic salts covering a broad range of cations (129), anions (17) and ligands (2) have been used in regressions to obtain group contributions for the parameters in the heat capacity temperature function. A mean error of 3.18% is found when predicted values are compared with literature values for heat capacity at 298{degrees} K. Estimates of the error standard deviation from the regression for each additivity constant are also determined.
Date: January 1, 1997
Creator: Mostafa, A. T. M. G.; Eakman, J. M. & Yarbro, S. L.
Partner: UNT Libraries Government Documents Department

Disposition of Mixed Waste Organics at the Los Alamos Plutonium Facility

Description: Twenty-six organic solution items totaling 37 L had been stored in the Plutonium Facility vault at the Los Alamos National Laboratory, some for up to 18 years. They were residues from analytical analyses of radioactive solutions. All items had a Resource Conservation and Recovery Act (RCRA) defined hazardous waste combined with special nuclear materials (SNM) and were stored as a mixed waste in a vault room pending disposition. Seventeen items had plutonium concentrations above established discard limits for organics. Due to their age, the containers were not suitable for long-term storage because a container failure would contaminate the vault area and personnel. Therefore, an aqueous-based flowsheet was developed to remove the plutonium so that the items could be discarded. The procedure was a wash with either sodium fluoride and/or potassium hydroxide solution followed by absorbing the discardable organic residues on vermiculite. When this approach did not work permission was obtained to discard the items as a transuranic (TRU) mixed waste without further treatment. The remaining nine solution items were consolidated into two items, repackaged, and stored for future disposition. The overall effort required approximately four months to disposition all the items. This report details the administrative and regulatory requirements that had to be addressed, the results of processing, and the current status of the items.
Date: February 1, 1999
Creator: Ortiz, E.M.; Coriz, F.; Schreiber, S.B.; Balkey, S. & Yarbro, S.L.
Partner: UNT Libraries Government Documents Department

Preparation of pure neptunium oxide for nondestructive assay standards

Description: Accurate nondestructive assay (NDA) measurements, particularly with gamma spectrometry, require pure material standards. The purity of materials used as standards is verified by reliable chemical techniques, and these materials are then used to calibrate and certify NDA instruments. So that they can be used for this purpose, impure NpO{sub 2} and metal were each purified by a different procedure. The NpO{sub 2}, which contained more than 2500 ppm plutonium, was purified by a double peroxide precipitation, followed by ion exchange and oxalate precipitation of the eluate. All impurities, including plutonium, were below 10 ppm in the product. The metal, which contained more than 10,000 ppm of tantalum, was dissolved in 12 M HCl and then precipitated as the Np(4) oxalate. The final product was below 100 ppm of all impurities except calcium. 1 ref., 2 tabs.
Date: March 1, 1991
Creator: Yarbro, S.L.; Dunn, S.L. & Schreiber, S.B.
Partner: UNT Libraries Government Documents Department

An introduction to the Advanced Testing Line for Actinide Separations (ATLAS)

Description: The Advanced Testing Line for Actinide Separations (ATLAS) will evaluate promising plutonium recovery process modifications and new technologies. It combines advances in process chemistry, process control, process analytical chemistry, and process engineering. ATLAS has a processing capability equal to other recovery systems but without the pressure to achieve predetermined recovery quotas.
Date: March 1, 1992
Creator: Pope, N.G.; Yarbro, S.L.; Schreiber, S.B. & Day, R.S.
Partner: UNT Libraries Government Documents Department

Evaluation of different solvent extraction methods for removing actinides from high acid waste streams

Description: At the Los Alamos National Laboratory Plutonium Facility, anion exchange is used to recover plutonium from nitric acid solutions. Although this approach recovers >99%, trace amounts of plutonium and other actinides remain the effluent and require additional processing. Currently, a ferric hydroxide carrier precipitation is used to remove the trace actinides and the resulting sludge is cemented. Because it costs approximately $10,000 per drum for disposal, we are developing an additional polishing step so that the effluent actinide levels are reduced to below 100 nCi/g. This would allow the resulting waste sludge to disposed as low-level waste at approximately $200 per drum. We are investigating various solvent extraction techniques for removing actinides. The most promising are chelating resins and membrane-based liquid-liquid solvent extraction. This report details some of our preliminary results. 4 refs., 3 tabs.
Date: January 1, 1991
Creator: Yarbro, S.L.; Schreiber, S.B.; Dunn, S.L. (Los Alamos National Lab., NM (United States)) & Rogers, J. (New Mexico State Univ., Las Cruces, NM (United States))
Partner: UNT Libraries Government Documents Department

Tank SY-102 remediation project: Flowsheet and conceptual design report

Description: The US Department of Energy established the Tank Waste Remediation System (TWRS) to safely manage and dispose of radioactive waste stored in underground tanks on the Hanford Site. A major program in TWRS is pretreatment which was established to process the waste prior to disposal. Pretreatment is needed to resolve tank safety issues and to separate wastes into high-level and low-level fractions for subsequent immobilization and disposal. There is a fixed inventory of actinides and fission products in the tank which must be prepared for disposal. By segregating the actinides and fission products from the bulk of the waste, the tank`s contents can be effectively managed. Due to the high public visibility and environmental sensitivity of this problem, real progress and demonstrated efforts toward addressing it must begin as soon as possible. As a part of this program, personnel at the Los Alamos National Laboratory (LANL) have developed and demonstrated a flowsheet to remediate tank SY-102 which is located in the 200 West Area and contains high-level radioactive waste. This report documents the results of the flowsheet demonstrations performed with simulated, but radioactive, wastes using an existing glovebox line at the Los Alamos Plutonium Facility. The tank waste was characterized using both a tank history approach and an exhaustive evaluation of the available core sample analyses. This report also presents a conceptual design complete with a working material flow model, a major equipment list, and cost estimates.
Date: January 1, 1994
Creator: Yarbro, S. L.; Punjak, W. A.; Schreiber, S. B.; Dunn, S. L.; Jarvinen, G. D.; Marsh, S. F. et al.
Partner: UNT Libraries Government Documents Department

Computer-based supervisory control and data acquisition system for the radioactive waste evaporator

Description: The evaporator process at TA-55 reduces the amount of transuranic liquid radioactive waste by separating radioactive salts from relatively low-level radioactive nitric acid solution. A computer-based supervisory control and data acquisition (SCADA) system has been installed on the process that allows the operators to easily interface with process equipment. Individual single-loop controllers in the SCADA system allow more precise process operation with less human intervention. With this system, process data can be archieved in computer files for later analysis. Data are distributed throughout the TA-55 site through a local area network so that real-time process conditions can be monitored at multiple locations. The entire system has been built using commercially available hardware and software components.
Date: December 1, 1994
Creator: Pope, N. G.; Schreiber, S. B.; Yarbro, S. L.; Gomez, B. G.; Nekimken, H. L.; Sanchez, D. E. et al.
Partner: UNT Libraries Government Documents Department