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Dostoman Code: A Compartmental Pathways Computer Model of Contaminant Transport

Description: Assessing the impact of radioactive and hazardous chemical waste disposal on man is an important problem in environmental science and engineering. This report illustrates the mathematical evolution of the compartmental model from small to large systems and provides examples of the use of the compartmental approach in analysis of transport of radionuclide and chemical contaminants.
Date: August 19, 2002
Creator: King, C.M.
Partner: UNT Libraries Government Documents Department

On-line slurry viscosity and concentration measurement as a real-time waste stream characterization tool. 1998 annual progress report

Description: 'This project seeks to develop an on-line sensor to measure the viscosity of dense slurries. This report summarizes work after two years of a three year project. The flow behavior of slurries is important for many of the proposed unit operations to be used in the conveying and processing of tank wastes. One alternative for determining the rheological properties of such materials is to obtain samples and test them off-line using conventional rheometers. Such a protocol is not practical for a wide variety of wastes. Rather, it is the goal of this work to find on-line, in-process techniques for measurement. There are two systems that the authors have propose examining: (1) Nuclear magnetic resonance imaging (NMRI), and, (2) Ultrasonic Doppler Velocimetry. Central to both of these techniques is the measurement of velocity profiles in pipe flows. For the NMRI measurements, the presence of particles has two principal effects on the NMRI velocity profiles: a decrease in signal intensity and image blurring. Similar effects are observed in turbulent flows due to the local random fluctuations in the flow. This similarity has led us to turbulent flow using NMRI. The governing equations for the signal obtained by NMRI are the Bloch-Torrey equations. Previously, the author showed a relationship between turbulent fluctuations and spatial signal intensity variations, assuming isotropic turbulence. However, this assumption does not reflect the true nature of turbulence in a pipe flow where the turbulence is not isotropic. In the new work the Bloch-Torrey equations will be solved by first, time averaging and then employing a turbulence model for pipe flow. The purpose of the time averaging is to smooth the fluctuations of time scale smaller than that of NMRI data acquisition. After this work with single phase fluids, the authors shall undertake NMRI experiments of slurry flow. Various operational ...
Date: June 1, 1998
Creator: Powell, R. L.
Partner: UNT Libraries Government Documents Department

Thermospray mass spectrometry ionization processes fundamental mechanisms for speciation, separation and characterization of organic complexants in DOE wastes. 1998 annual progress report

Description: 'This is a three-year project which started on October 1, 1997. This report summarizes the progress achieved for the first eight months of the study (through May, 1998). Thermospray positive ion mass spectra of seven different organic complexants have been defined in a water:methanol (1:1 by volume) solvent system that was buffered with 0.1 M ammonium acetate (pH = 6.7). These complexants were imidodiacetic acid (IDA), ethylenediamine-N,N{prime}-diacetic acid (EDDA), N-(2-hydroxyethyl)iminodiacetic acid (HEIDA), nitrilotriacetic acid (NTA), N-(2-hydroxyethyl)ethylenediaminetriacetic acid (HEDTA), ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA). Mass spectra of all these complexants showed a peak at mass [M+1] + when vaporized from this solvent medium. Only NTA showed a significant peak at mass [M+18] + which was interpreted as the formation of an adduct with an ammonium ion from the buffered solvent medium. This observation for the vaporized NTA is consistent with the measured acidity in aqueous solution where the first acid dissociation for NTA has a lower pK value than those reported for EDTA, HEDTA, and IDA (1). This tendency to form an ammonium adduct in the gas phase would indicate that NTA has a lower proton affinity than the other complexants in the vaporized phase. This lower proton affinity in the vapor phase would be consistent with the greater observed acidity in the solution phase. Accordingly, this observation provides an indication that characteristics observed after thermospray vaporization may aid in defining behavior in solution. Such interpretations of thermospray mass spectra should be useful in the characterization of DOE mixed waste solutions. Progress has also been made in developing thermospray mass spectra at source temperatures of less than 170 C. Such lower source temperatures should reduce the amount to thermal degradation for labile species. Pressures in the analyzer chamber of the mass spectrometer tend to elevate as the thermospray source ...
Date: June 1, 1998
Creator: Caton, J.E.; Bostick, D.T. & Carr, P.W.
Partner: UNT Libraries Government Documents Department

Genetic engineering of a radiation-resistant bacterium for biodegradation of ixed wastes. 1998 annual progress report

Description: 'Because of their tolerance to very high levels of ionizing radiation, members of the genus Deinococcus have received considerable attention over the past years. The type species of the genus, Deinococcus radiodurans, has been studied extensively in several labs. Although researchers are only beginning to understand the mechanisms by which this Gram-positive bacterium is able to repair massive DNA damage after radiation dosages as high as 5 Mrad, it has become evident that its recombination machinery has several unique characteristics (1--4). The aim of the present studies is to engineer D. radiodurans into a detoxifier for bioremediation of complex waste mixtures, containing heavy metals, halo-organics and radionuclides, making use of its ability to be biologically active in environments where they will be exposed to high levels of radiation. For that purpose, the authors aim to clone and express several broad spectrum oxygenases and heavy metal resistance determinants, and test survival and activities of these strains in artificial mixtures of contaminants, designed to simulate DOE mixed waste streams. This report summarizes work after 0.5 year of a 3-year project. The initial studies have focused on the development of an insertional expression system for D. radiodurans R1. This effort has involved two parts, namely: (1) promoter analysis, and (2) development of insertion systems. Several studies have shown that the expression signals used by D. radiodurans differ considerably from those found in other bacteria. Although D. radiodurans contains a typical eubacterial RNA polymerase core enzyme (based on TBLASTN searches on the genome sequence), Escherichia coli promoters are not recognized in D. radiodurans and vice versa (5). To expand the basic understanding of the requirements for transcription, and to optimize expression of (heterologous) genes, they will follow two strategies. First, a promoter-probe vector is being developed for the selection of promoter sequences from the ...
Date: June 1, 1998
Creator: Lidstrom, M.E.
Partner: UNT Libraries Government Documents Department

Acid-base behavior in hydrothermal processing of wastes. 1997 annual progress report

Description: 'A major obstacle to the development of hydrothermal technology for treating DOE wastes has been a lack of scientific knowledge of solution chemistry, thermodynamics and transport phenomena. The progress over the last year is highlighted in the following four abstracts from manuscripts which have been submitted to journals. The authors also have made considerable progress on a spectroscopic study of the acid-base equilibria of Cr(VI). They have utilized novel spectroscopic indicators to study acid-base equilibria up to 380 C. Until now, very few systems have been studied at such high temperatures, although this information is vital for hydrothermal processing of wastes. The pH values of aqueous solutions of boric acid and KOH were measured with the optical indicator 2-naphthol at temperatures from 300 to 380 C. The equilibrium constant Kb-l for the reaction B(OH)3 + OH{sup -} = B(OH){sup -4} was determined from the pH measurements and correlated with a modified Born model. The titration curve for the addition of HCl to sodium borate exhibits strong acid-strong base behavior even at 350 C and 24.1 MPa. At these conditions, aqueous solutions of sodium borate buffer the pH at 9.6 t 0.25. submitted to Ind. Eng. Chem. Res. Acetic Acid and HCl Acid-base titrations for the KOH-acetic acid or NH{sub 3} -acetic acid systems were monitored with the optical indicator 2-naphthoic acid at 350 C and 34 MPa, and those for the HCl;Cl- system with acridine at 380 C and up to 34 MPa (5,000 psia ). KOH remains a much stronger base than NH,OH at high temperature. From 298 K to the critical temperature of water, the dissociation constant for HCl decreases by 13 orders of magnitude, and thus, the basicity of Cl{sup -} becomes significant. Consequently, the addition of NaCl to HCl raises the pH. The pH titration curves ...
Date: January 1, 1997
Partner: UNT Libraries Government Documents Department

Acoustic probe for solid-gas-liquid suspensions. 1998 annual progress report

Description: 'The proposed research will develop an acoustic probe for monitoring particle size and volume fraction in slurries in the absence and presence of gas. The goals are to commission and verify the probe components and system operation, develop theory for the forward and inverse problems for acoustic wave propagation through a three phase medium, and experimentally verify the theoretical analysis. The acoustic probe will permit measurement of solid content in gas-liquid-solid waste slurries in tanks across the DOE complex.'
Date: June 1, 1998
Creator: Tavlarides, L.L.; Sangani, A.S. & Greenwood, M.S.
Partner: UNT Libraries Government Documents Department

Hazardous gas production by alpha particles in solid organic transuranic waste matrices. 1998 annual progress report

Description: 'This project uses fundamental radiation chemical techniques to elucidate the basic processes occurring in the heavy-ion radiolysis of solid hydrocarbon matrices such as polymers and organic resins that are associated with many of the transuranic waste deposits or the transportation of these radionuclides. The environmental management of mixed waste containing transuranic radionuclides is difficult because these nuclides are alpha particle emitters and the energy deposited by the alpha particles causes chemical transformations in the matrices accompanying the waste. Most radiolysis programs focus on conventional radiation such as gamma rays, but the chemical changes induced by alpha particles and other heavy ions are typically very different and product yields can vary by more than an order of magnitude. The objective of this research is to measure the production of gases, especially molecular hydrogen, produced in the proton, helium ion, and carbon ion radiolysis of selected solid organic matrices in order to obtain fundamental mechanistic information on the radiolytic decomposition of these materials. This knowledge can also be used to directly give reasonable estimates of explosive or flammability hazards in the storage or transport of transuranic wastes in order to enhance the safety of DOE sites. This report summarizes the work after eight months of a three-year project on determining the production of hazardous gases in transuranic waste. The first stage of the project was to design and build an assembly to irradiate solid organic matrices using accelerated ion beams. It is necessary to measure absolute radiolytic yields, and simulate some of the conditions found in the field. A window assembly was constructed allowing the beam to pass consecutively through a collimator, a vacuum exit window and into the solid sample. The beam is stopped in the sample and the entire end of the assembly is a Faraday cup. Integration of the ...
Date: June 1, 1998
Creator: LaVerne, J.A.
Partner: UNT Libraries Government Documents Department

On-line slurry viscosity and concentration measurement as a real-time waste stream characterization tool. 1997 annual progress report

Description: 'The main scope of this work is to: (1) develop a novel tomographic ultrasonic technique to obtain the real-time distribution of acoustic velocity and flow velocity; (2) use nuclear magnetic resonance imaging (NMRI) to measure velocity profiles and rheological properties of complex fluids and suspensions; (3) establish a facility for making laser Doppler velocimetry (LDV) measurements that can be The overall goal is to obtain real-time rheology and solids concentration within a solid-liquid suspension flowing in a pipeline. To nondestructively obtain the rheology of the fluid flowing in a pipe, accurate measurement of local shear rate distribution is required. This objective was met by using two real-time tomographic techniques: an ultrasonic Doppler velocimetry system and an NMRI system. The first method combines the existing state-of-the-art ultrasonic velocimetry technology base with a novel tomographic concept to non-intrusively obtain high resolution acoustic and flow velocity profile at a section of the flow field. The acoustic velocity profile provides a means of improving the flow velocity measurement accuracy. These data are also, used to yield the profile of solids concentration. In addition, the volumetric flow rate was determined from integration of the velocity profile. From the knowledge of the concentration profile the mass flow rate can also be determined, Similar work was undertaken for the NMNRI system. In this case, single phase Newtonian fluids have been used to model complex rheological behavior. Finally, a LDV system has been purchased and set - up in the laboratory at UC Davis.'
Date: January 1, 1997
Creator: Powell, R. L. & Shekarriz, A.
Partner: UNT Libraries Government Documents Department

Acoustic probe for solid-gas-liquid suspensions. 1997 annual progress report

Description: 'Acoustic probes have shown promise to be quite effective in determining the solid content in solid-liquid suspensions. However, the presence of small amounts of gas in the waste slurries stored in tanks across the DOE complex prevents straightforward application for characterization of these slurries. The proposed research will develop an acoustic probe for monitoring particle size and volume fraction in slurries in the absence and the presence of gas bubbles. Theoretical Analysis Accomplished: Attenuation of sound waves depends on the size distribution of the solids and the volume fraction of solids. These can in principle be calculated from attenuation measured over a range of frequencies. However, small amounts of bubbles distort the measured attenuation. A typical result from theoretical analysis for the attenuation of solid- gas-liquid systems is given in Figure 1. The total attenuation of a sound wave v(o) equals the sum of contributions by a large number of ''bins'' of particle sizes. This notion yields the following equation for the (hitherto) unknown number density of solid particles as a function of particle radius N(a): j k(o,a)N(a)da = v(o), where the kernel k(o,a) is obtained from analysis. If N(a) is given, the above equation is used to calculate the attenuation v(o). This is referred to as solving the ''forward problem''. Solving for N(a) with v(o) given is the ''inverse problem''. A complication that one faces when trying to solve the inverse problem is that the stated problem is mathematically ill-posed, i.e., small fluctuations in v(o) cause large fluctuations in the result for the number density. Therefore the problem needs to be ''regularized'', i.e., the stated problem needs to be changed slightly such as to make it well-posed. This has been done by others for gas-liquid systems in the past. This approach is currently being applied in the present project ...
Date: January 1, 1997
Creator: Tavlarides, L. L. & Sangani, A. S.
Partner: UNT Libraries Government Documents Department

Acid-base behavior in hydrothermal processing of wastes. 1998 annual progress report

Description: 'A new technology, hydrothermal oxidation (also called supercritical water oxidation), is being developed to treat high level nuclear wastes. Nitrates are reduced to nitrogen; furthermore, phosphates, alumina sludge, and chromium are solubilized, and the sludge is reconstituted as fine oxide particles. A major obstacle to development of this technology has been a lack of scientific knowledge of chemistry in hydrothermal solution above 350 C, particularly acid-base behavior, and transport phenomena, which is needed to understand corrosion, metal-ion complexation, and salt precipitation and recovery. The objective is to provide this knowledge with in-situ UV-vis spectroscopic measurements and fully molecular computer simulation. A major objective of the experimental studies has been to determine the equilibria for Cr(VI) up to 420 C as this is a key species to be removed from nuclear wastes. A wide range of concentrations of KOH and perchloric acid were utilized to manipulate the acid-base equilibria and to understand the effects of ion solvation and ion pairing. The second system is the equilibria between nitric acid, nitrous acid, nitrogen dioxide, nitrite and nitrate ions and oxygen. For both of these systems, chemical equilibria has not been measured previously in hydrothermal solution at these temperatures. On the theoretical side, the authors have focused on the study of the transport properties of aqueous ions in supercritical water. The motivation for these studies is two fold. First, although transport coefficients are fundamental to solution chemistry reaction rates, the behavior of such transport properties over wide ranges of density and temperature are not well established experimentally, particularly at the densities typically of interest (< 0.5 g/cc). Second, due to practical challenges, ionic association equilibria in SCW is typically accessed via measurements of conductivity followed by analysis through a theoretical model that incorporates ion pairing. The results of these analyses in the interesting ...
Date: June 1, 1998
Creator: Johnson, K.P. & Rossky, P.J.
Partner: UNT Libraries Government Documents Department

Development of an in-situ microsensor for the measurements of chromium and uranium in groundwater at DOE sites. 1998 annual progress report

Description: 'The goal of this research is to develop novel electrochemical sensors for in-situ environmental monitoring of trace uranium and chromium. Such innovative remote/submersible and micromachined stripping-based devices will greatly enhance the detection of trace metals in a field setting, and should revolutionize the way such contaminants are being monitored. This report summarizes activity over the first 1.5 years of a 3-year project. This effort has led to the replacement of conventional stripping electrochemical protocols and systems with new innovative strategies for field monitoring of trace uranium and chromium, based on remotely deployable submersible sensors and micromachined hand-held total stripping analyzers. Eventually, these developments will allow to move the measurement of these metals to the field and to perform them more rapidly, reliably and inexpensively. Improved Stripping Procedures for U and Cr Traditionally, Cr and U have been measured separately using the adsorptive accumulation of their complexes with DTPA and propyl gallate (PG), respectively. To facilitate their on-site detection, the authors have developed new adsorptive stripping protocols that allow the simultaneous and rapid detection of Cr and U down to low ppb concentrations. One such new scheme involves the use of a mixed ligand (DTPA/PG) solution that allows simultaneous trace measurements in a single run (1). Numerous experimental parameters were optimized to assure that the attractive performance of the individual single-element protocols are not compromised. Simultaneous measurements in groundwater samples were documented. Alternately, they employed a single but more universal ligand (cupferron) for the simultaneous monitoring of Cr and U (2). Under optimal conditions, competition of these metals for the ligand and coadsoprtion effects were minimized, and different concentrations of the mixture components can be tolerated. A major goal and focus of this project has been the development of a miniaturized stripping analytical system, produced by micromachining technology. Such new micromachined ...
Date: June 1, 1998
Creator: Wang, J.
Partner: UNT Libraries Government Documents Department

Improved analytical characterization of solid waste forms (glass, metals, soils) by fundamental development of the laser ablation technology. 1997 annual progress report

Description: 'Laser ablation is a promising technology for chemical characterization within every DOE EM major problem area (high-level waste tanks, contaminant plumes, D and D activities, spent nuclear fuel, mixed wastes, landfills, nuclear waste disposal, and HEU disposition). This EMSP research endeavors to expand the fundamental basis in laser ablation technology for its application to these DOE characterization needs. Laser ablation must be understood on a fundamental level to ensure confidence in chemical characterization of environmental samples. The goal is to develop a fundamental understanding of laser ablation processes, and to determine the influence of these processes on analytical behavior (sensitivity and accuracy) in order to bring this technology to fruition. This report summarizes the research completed in the first year of this project. The initial work addressed: accuracy of chemical characterization by verifying that the ICP (inductively coupled plasma) was not adversely influenced by ablated mass; accuracy of ablation sampling versus laser pulse time; and sensitivity enhancements through the use of various gas environments. The research and development utilized an existing ICP-AES system. Part of the effort also included the evaluation, purchase, and installation of an ICP-MS system. Three scientific manuscripts were completed and submitted to technical journals. One of the goals of this work is to support the efforts at all the National Laboratories investigating laser ablation technology for the management of DOE radioactive, hazardous chemical, and mixed waste; collaborations with scientists at other National Laboratories have been initiated.'
Date: January 1, 1997
Creator: Russo, R.E.
Partner: UNT Libraries Government Documents Department

Investigation of novel electrode materials for electrochemically-based remediation of high- and low-level mixed wastes in the DOE complex. 1998 annual progress report

Description: 'One of the key issues that must be solved to achieve a successful remediation of the high level liquid wastes (HLW) at the Hanford and at Savannah River sites is the removal of the significant quantities of nitrate and nitrite in the existing liquid waste streams that are presently on these sites in the DOE complex. One method of waste stream remediation is electrochemical oxidation, which is an in-situ method that has been well-documented to have significant advantages in many areas with respect to pump-and-treat approaches to waste remediation. There are, however, significant aspects of the electrochemical oxidation process that need to be addressed from a basic research viewpoint. The research to be performed under this proposal will investigate new materials, initially based on degenerately-doped titanias, for use in the electrochemical degradation of organics and nitrogen-containing compounds in sites of concern to the DOE remediation effort. This report summarizes work after 1.5 years of a 3-year project. Progress has been made in two main areas of work. First, significant effort has been made in synthesis and characterization of new anode materials for electrochemical remediation purposes. Secondly, these materials have also been characterized as photoanodes for photoelectrochemical activity and remediation applications. Due to space limitations, only work in the former area is summarized here but information on the latter is of course available upon request from the PI''s.'
Date: June 1, 1998
Creator: Lewis, N.S.
Partner: UNT Libraries Government Documents Department

Novel ceramic-polymer composite membranes for the separation of hazardous liquid waste. 1998 annual progress report

Description: 'This report summarizes the work progress over the last 1.75 years of a 3 year project. The objectives of the project have been to develop a new class of ceramic-supported polymeric membranes that could be tailored-designed for a wide-range of applications in remediation and pollution prevention. To date, a new class of chemically-modified ceramic membranes was developed for the treatment of oil-in-water emulsions and for the pervaporation removal of volatile organics from aqueous systems. These new ceramic-supported polymer (CSP) membranes are fabricated by modifying the pore surface of a ceramic membrane support by a graft polymerization process (Chaimberg and Cohen, 1994). The graft polymerization process consists of activating the membrane surface with alkoxy vinyl silanes onto which vinyl monomers are added via free-radical graft polymerization resulting in a thin surface layer of terminally anchored polymer chains. Reaction conditions are selected based on knowledge of the graft polymerization kinetics for the specific polymer/substrate system. The resultant ceramic-supported polymer (CSP) membrane is a composite structure in which mechanical strength is provided by the ceramic support and the selectivity is determined by the covalently bonded polymer brush layer. Thus, one of the unique attributes of the CSP membrane is that it can be used in environments where the polymer layer is swollen (or even completely miscible) in the mixture to be separated (Castro et al., 1993). It is important to note that the above modification process is carried out under mild conditions (e.g., temperature of about 70 C) and is well suited for large scale commercial application. In a series of studies, the applicability of a polyvinylpyrrolidone CSP membrane was demonstrated for the treatment of oil-in-water emulsion under a variety of flow conditions (Castro et al.,1996). Improved membrane performance was achieved due to minimization of surface adsorption of the oil components. For the ...
Date: June 1, 1998
Creator: Cohen, Y.
Partner: UNT Libraries Government Documents Department

Improved analytical characterization of solid waste-forms by fundamental development of laser ablation technology. 1998 annual progress report

Description: 'This EMSP research endeavors to understand fundamental laser-ablation sampling processes and to determine the influence of these processes on analytical characterization of EM waste-site samples. The issues germane to the EMSP are sensitivity and accuracy of analysis. These issues are researched by studying fractionation, sample transport, mass loading, and analytical system optimization. Inductively coupled plasma-mass spectroscopy (ICP-MS) is emphasized in this research because of its use throughout the DOE labs and sites. This report summarizes research performed over the first half of this three-year program. Four issues were emphasized to improve analytical sensitivity and accuracy, including the time dependent laser removal of mass from a solid sample, fractionation, particle generation and transport, and optimization of the ICP-MS for laser ablation sampling. This research has led to six journal publications.'
Date: June 1, 1998
Creator: Russo, R.E.
Partner: UNT Libraries Government Documents Department

Development of advanced in-situ techniques for chemistry monitoring and corrosion mitigation in SCWO environments. 1998 annual progress report

Description: 'This report evaluates the two years results of the research on the development of advanced electrochemical techniques for use in supercritical water oxidation (SCWO) environments. The SCWO technology was found to be a promising approach to treat a variety of hazardous wastes. However, the corrosion processes in the SCWO reactors is still a problem for further development of this technology. The authors have developed a flow-through electrochemical cell (FTEC) which allows us to monitor the corrosion process in real time at temperatures up to 500 C and pressures up to 400 bar. The FTEC consists of a flow-through Ag/AgCl external pressure-balanced reference electrode, a flow-through platinum hydrogen electrode, an yttria-stabilized zirconia pH sensor and an electrochemical noise sensor. The new FTEC has been designed to serve as a measurement vessel for the high temperature and high pressure circulation once-through flow loop and titanium alloy was chosen as the construction material. The FTEC, shown schematically in Figure 1, is used for the experiments. Two HPLC pumps are employed in the system, one for pumping the reaction solution through the loop and the other for pumping the reference solution through the reference electrode. The system pressure is sustained as a constant via a back pressure regulator. The temperature was measured using a thermocouple installed at the center of the FTEC. Because many physico-chemical processes, including corrosion, are sensitive to the pH, the measurement and control of pH is very important for the high temperature SCWO environment. The authors have measured the potentials of the FTEC for several HCl(aq) + NaCl(aq) solutions of different concentrations of HCl(aq) and derived the corresponding pH differences ({Delta}pH) over a wide range of temperatures at pressure around 350 bar. Comparison of the experimentally derived and theoretically calculated DpH values presented in Figure 2 clearly demonstrates the ability ...
Date: June 1, 1998
Creator: Macdonald, D.D.; Engelhardt, G. & Garcia, K.M.
Partner: UNT Libraries Government Documents Department

Studies related to chemical mechanisms of gas formation in Hanford high-level nuclear wastes. 1997 annual progress report

Description: 'Work during the past year has been concentrated in three areas: Analysis of the Relative Contributions of Thermal versus Radiolytic Pathways for Complexant Decomposition in Tank 101SY; Synthesis of Potential Precursors to HNO/NO{sup -}, and Analysis of the Kinetics of Decomposition of Piloty''s Acid at High [OH{sup -}]. The undergraduate student worked on the aluminum catalyzed reactions of nitrite ion with 2-hydroxyethylamines. This is a follow-up to earlier work done under Westinghouse Hanford and PNNL funding that will be expanded to include an exploration of the complexation of nitrite ion by aluminum when Ms. Chalfant''s lab skills are sufficiently established. A brief synopsis of work in each of the first three areas.'
Date: January 1, 1997
Creator: Barefield, E.K.; Liotta, C.L. & Neumann, H.M.
Partner: UNT Libraries Government Documents Department

Development of an in-situ microsensor for the measurement of chromium and uranium in groundwater in DOE sites. Progress report, September 15, 1996-September 14, 1997

Description: 'The goal of this project is to develop, optimize and deploy a silicon-based micromachined stripping analyzer for field monitoring of trace levels of chromium and uranium. Such system will integrate sample-handling steps and necessary chemical reactions (using a flow-injection operation) with the already proven adsorptive stripping operation on a small planar chip. Besides the drastic reduction in the size of the analytical system, such miniaturization should lead to increased speed, minimal reagent consumption and disposal, higher sensitivity and improved precision and would revolutionize the way by which toxic metals are being monitored. The work during the first year has focused on three directions: (1) design and fabrication of the micromachined flow system for stripping measurements of chromium and uranium; (2) design and evaluation of a remote sensor for in-situ monitoring of chromium and uranium; and (3) developing and characterizing new electrodes for adsorptive stripping measurements of chromium and uranium.'
Date: January 1, 1997
Creator: Wang, J.
Partner: UNT Libraries Government Documents Department

Foaming in radioactive waste treatment and immobilization processes. 1998 annual progress report

Description: 'The objective of this research is to gain a basic understanding of the mechanisms that produce foaming during nuclear waste treatment, to identify the key parameters which aggravate foaming, and to identify effective ways to eliminate or mitigate foaming. The specific goal of this part of the study is to reveal the role of solid particles in colloidal range in foam formation and foam stability. The result of this study will aid in eliminating foaminess in three-phase gas/liquid/solid systems, thereby facilitating implementation of environmental technologies for radioactive waste treatment and waste immobilization processes. This report summarizes work completed during the first year of a three-year project. To characterize the foam and identify key parameters for foaminess in a three-phase gas/liquid/solid system, a simulated (non-radioactive) acidified sludge was used. The sludge samples were prepared using PUREX sludge simulant and PHA (Precipitate Hydrolysis Aqueous) was prepared using irradiated precipitate. The pH of the sludge samples was 6.0--6.5 and pH of PHA was 4.0. Both of these samples were prepared at Savannah River Technical Center (SRTC) and were shipped to the laboratory at Illinois Institute of Technology, Chicago. The sludge contained Al (3.8 wt%), Hg (3.5 wt%), Fe (25.5 wt%) on dry basis and noble metals (Rh, Ru, Pd, Ag, Se) in small concentrations. The sludge particles were polydispersed in size varying from about 0.05\265m to 10\265m. Such a sludge sample is a good model representation of actual nuclear sludge. However, the preparation of sludge in terms of its constituents affects the foaminess.'
Date: June 1, 1998
Creator: Wasan, D.T.
Partner: UNT Libraries Government Documents Department

A broad spectrum catalytic system for removal of toxic organics from water by deep oxidation. 1998 annual progress report

Description: 'Toxic organics and polymers pose a serious threat to the environment, especially when they are present in aquatic systems. The objective of the research is the design of practical procedures for the removal and/or recycling of such pollutants by oxidation. This report summarizes the work performed in the first one and half years of a three year project. The authors had earlier described a catalytic system for the deep oxidation of toxic organics, such as benzene, phenol and substituted phenols, aliphatic and aromatic halogenated compounds, organophosphorus, and organosulfur compounds [1]. In this system, metallic palladium was found to catalyze the oxidation of the substrate by dioxygen in aqueous medium at 80--100 C in the presence of carbon monoxide. For all the substrates examined, deep oxidation to carbon monoxide, carbon dioxide, and water occurred in high yields, resulting in up to several hundred turnovers over a 24 h period. Because of a pressing need for new procedures for the destruction of chemical warfare agents, the authors have examined in detail the deep oxidation of appropriate model compounds containing phosphorus-carbon and sulfur-carbon bonds using the same catalytic system. The result is the first observation of the efficient catalytic oxidative cleavage of phosphorus-carbon and sulfur-carbon bonds under mild conditions, using dioxygen as the oxidant [2]. In addition to the achievements described above, they have unpublished results in several other areas. For example, they have investigated the possibility of using dihydrogen rather than carbon monoxide as a coreductant in the catalytic deep oxidation of substrates. Even more attractive from a practical standpoint is the possibility of using a mixture of carbon monoxide and dihydrogen (synthesis gas). Indeed, experiments indicated that it is possible to substitute carbon monoxide by dihydrogen or synthesis gas. Significantly, in the case of nitro compounds, the deep oxidation in fact ...
Date: June 1, 1998
Creator: Sen, A.
Partner: UNT Libraries Government Documents Department

A fundamental study of laser-induced breakdown spectroscopy using fiber optics for remote measurements of trace metals. Interim progress report

Description: 'The long-term goal of this project is to develop a system to measure the elemental composition of unprepared samples using laser-induced breakdown spectroscopy, LIBS, with a fiber-optic probe. From images shown in this report it is evident that the temporal and spatial behavior of laser-induced plasmas IS a complex process. However, through the use of spectral imaging, optimal conditions can be determined for collecting the atomic emission signal in these plasmas. By tailoring signal collection to the regions of the plasma that contain the highest emission signal with the least amount of background interference both the detection limits and the precision of LIBS measurements could be improved. The optimal regions for both gated and possibly non-gated LIBS measurements have been shown to correspond to the inner regions and outer regions, respectively, in an axial plasma. By using this data fiber-optic LIBS probe designs can be optimized for collecting plasma emission at the optimal regions for improved detection limits and precision in a LIBS measurement.'
Date: January 1, 1997
Creator: Goode, S.R. & Angel, S.M.
Partner: UNT Libraries Government Documents Department

Ion-exchange processes and mechanisms in glasses

Description: 'Recent performance assessment calculations of a disposal system at the Hanford Site in Washington State for low-activity waste glass show that a sodium ion exchange reaction can effectively increase the radionuclide release rate by over a factor of 1,000. The susceptibility of the glass to alkali ion exchange is thus a major factor limiting waste loading. However, low temperature ion exchange has not been thought to be important in recent analyses of waste glass durability. The objective of this work is to develop an understanding of the processes and mechanisms controlling alkali ion exchange and to correlate the kinetics of the ion exchange reaction with glass structural properties. The fundamental understanding of the ion exchange process developed under this study is targeted at developing lower ion-exchange rate glasses that would remain durable at higher alkali waste loading. This report summarizes eight months of work on this three-year project that is being performed cooperatively between Pacific Northwest National Laboratory and Lawrence Berkeley National Laboratory.'
Date: June 1, 1998
Creator: McGrail, B.P.; Shuh, D.K.; Darab, J.G. & Baer, D.R.
Partner: UNT Libraries Government Documents Department

Design and synthesis of the next generation of crown ethers for waste separations: An interlaboratory comprehensive proposal. 1997 annual progress report

Description: 'The purpose of this task is to undertake the design, synthesis, and characterization of the next generation of crown ethers for metal-ion separations applicable to the US Department of Energy''s (DOE''s) environmental needs. The general target problem is the removal of alkali and alkaline-earth metal contaminants from certain environmental and waste streams. Although not a radioactivity hazard, Li{sup +} ions leaching from burial sites containing more than 12 metric tons of lithium compounds contaminate the groundwater at the Oak Ridge Y-12 Plant and have raised noncompliance concerns because of the resultant toxicity to aquatic biota. A more highly visible problem has been treatment of high-level wastes stored in underground tanks at Oak Ridge National Laboratory (ORNL), Idaho National Engineering and Environmental Laboratory, and especially the Hanford Site. The fission products {sup 90}Sr and {sup 137}Cs have been explicitly targeted for removal by the following DOE programs: the Office of Environmental Management, the Office of Science and Technology, the Tank Waste Remediation System, the Tanks Focus Area, and the Efficient Separations and Processing Cross-Cutting Program. These seemingly ubiquitous fission products also appear in soil and groundwater at numerous DOE sites. In addition, radium has recently been named as a target contaminant at the Niagara Falls Storage Site. Unfortunately, the separations technologies needed to address these problems either do not exist or exhibit substantial deficiencies. Established techniques such as solvent extraction and ion exchange certainly have a strong role to play, especially as enhanced with the use of the new highly selective metal-ion hosts such as crown ethers and calixarenes. Recently applied results in the United States, France, Russia, and elsewhere have demonstrated the effective performance of crown ethers under realistic or actual process conditions for the removal of alkali and alkaline-earth metal ions from waste, including high-levelnuclear waste. From these results, ...
Date: September 1, 1997
Creator: Moyer, B.A.; Dietz, M.L.; Alexandratos, S.D. & Hay, B.P.
Partner: UNT Libraries Government Documents Department