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Peak Stripping Methodology for Plutonium Analysis in the Presence of Neptunium

Description: Quantitative Plutonium analysis depends upon the accurate identification of the assay peak. The Np[Pa] equilibrium pair introduces interfering peaks in {sup 239}Pu, {sup 238}Pu, and {sup 235}U assay peak region. When an interfering peak is present, it negates the assay unless an appropriate technique can be developed to deal with the interference. Peak Stripping is one such technique. Peak stripping involves an algorithm to strip an entire peak from another, resulting in a spectrum that can then be analyzed for the isotope of interest. A simpler method is a ''pseudo-peak-stripping'' whereby the effects of the interfering peak are quantified and those effects are stripped from the assay data. In this case the integrated peak areas are analyzed and corrected. There are two methods presented in this paper. Both assimilate the integrated data for the assay peak regions (in this case {sup 238}Pu, {sup 239}Pu, and {sup 235}U) and for the Neptunium/Protactinium secular equilibrium pair (Np[Pa]). Using Np[Pa] assumes that the Protactinium has come to equilibrium with Neptunium. This requires only {approx}6 months from the time chemical purification. Therefore it is a valid assumption in most cases. A correction is then applied to the assay peak areas to ''strip'' the underlying effects of Np[Pa].
Date: May 17, 2005
Creator: Hodge, Christ
Partner: UNT Libraries Government Documents Department

EVALUATING EFFECTS OF NEPTUNIUM ON THE SRS METHOD FOR CONTROLLED POTENTIAL COULOMETRIC ASSAY OF PLUTONIUM IN SULFURIC ACID SUPPORTING ELECTROLYTE

Description: A study of the impact of neptunium on the coulometric assay of plutonium in dilute sulfuric acid was performed. Weight aliquots of plutonium standard solutions were spiked with purified neptunium solution to evaluate plutonium measurement performance for aliquots with Pu:Np ratios of 50:1, 30:1, 20:1, 15:1, and 10:1. Weight aliquots of the pure plutonium standard solution were measured as controls. Routine plutonium instrument control standards were also measured. The presence of neptunium in plutonium aliquots significantly increases the random uncertainty associated with the plutonium coulometric measurement performed in accordance with ISO12183:2005.7 However, the presence of neptunium does not appear to degrade electrode performance and conditioning as aliquots of pure plutonium that were interspersed during the measurement of the mixed Pu:Np aliquots continued to achieve the historical short-term random uncertainty for the method. Lack of adequate control of the neptunium oxidation state is suspected to be the primary cause of the elevated measurement uncertainty and will be pursued in a future study.
Date: May 9, 2008
Creator: Holland, M & Sheldon Nichols, S
Partner: UNT Libraries Government Documents Department

NEW METHOD FOR REMOVAL OF SPECTRAL INTERFERENCES FOR BERYLLIUM ASSAY USING INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION SPECTROMETRY

Description: Beryllium has been used widely in specific areas of nuclear technology. Frequent monitoring of air and possible contaminated surfaces in U.S Department of Energy (DOE) facilities is required to identify potential health risks and to protect DOE workers from beryllium-contaminated dust. A new method has been developed to rapidly remove spectral interferences prior to beryllium (Be) measurement by inductively-coupled plasma atomic emission spectrometry (ICP-AES). The ion exchange separation removes uranium (U), thorium (Th), niobium (Nb), vanadium (V), molybdenum (Mo), zirconium (Zr), tungsten (W), iron (Fe), chromium (Cr), cerium (Ce), erbium (Er) and titanium (Ti). A stacked column consisting of Diphonix Resin{reg_sign} and TEVA Resin{reg_sign} reduces the levels of the spectral interferences so that low level Be measurements can be performed accurately. If necessary, an additional anion exchange separation can be used for further removal of interferences, particularly chromium. The method has been tested using spiked filters, spiked wipe samples and certified reference material standards with high levels of interferences added. The method provides very efficient removal of spectral interferences with very good accuracy and precision for beryllium on filters or wipes. A vacuum box system is employed to reduce analytical time and reduce labor costs.
Date: January 14, 2008
Creator: Maxwell, S; Matthew Nelson, M; Linda Youmans, L & Maureen Bernard, M
Partner: UNT Libraries Government Documents Department

Unique applications of solvent removal in inductively coupled plasma mass spectrometry

Description: Inductively coupled plasma mass spectrometry (ICP-MS) is the technique of choice for rapid, high precision, semiquantitative elemental and isotopic analysis for over 70 elements. Less than 20 years after the first mass spectrum was obtained by ICP-MS, this technique has applications in clinical chemistry, geochemistry, the semiconductor industry, the nuclear industry, environmental chemistry, and forensic chemistry. The determination of many elements, though, by ICP-MS is complicated by spectral interferences from background species, interelement spectral overlaps, and polyatomic ions of matrix elements. The emphasis of this thesis is the unique applications of solvent removal using cryogenic and membrane desolvation. Chapter 1 is a general introduction providing background information concerning the need for these methods and some information about the methods themselves. Chapter 5 discusses general conclusions and general observations pertaining to this work. Chapters 2, 3, and 4 have been processed separately for inclusion on the database. Chapter 2 describes a method to screen urine samples for vanadium using cryogenic desolvation. Chapter 3 compares solvent removal by cryogenic and membrane desolvation. Chapter 4 describes the use of cool plasma conditions for the determination of potassium in the presence of excess sodium by ICP-MS.
Date: January 10, 1997
Creator: Minnich, M.
Partner: UNT Libraries Government Documents Department

Matrix effects in inductively coupled plasma mass spectrometry

Description: The inductively coupled plasma is an electrodeless discharge in a gas (usually Ar) at atmospheric pressure. Radio frequency energy generated by a RF power source is inductively coupled to the plasma gas through a water cooled load coil. In ICP-MS the {open_quotes}Fassel{close_quotes} TAX quartz torch commonly used in emission is mounted horizontally. The sample aerosol is introduced into the central flow, where the gas kinetic temperature is about 5000 K. The aerosol is vaporized, atomized, excited and ionized in the plasma, and the ions are subsequently extracted through two metal apertures (sampler and skimmer) into the mass spectrometer. In ICP-MS, the matrix effects, or non-spectroscopic interferences, can be defined as the type of interferences caused by dissolved concomitant salt ions in the solution. Matrix effects can be divided into two categories: (1) signal drift due to the deposition of solids on the sampling apertures; and/or (2) signal suppression or enhancement by the presence of the dissolved salts. The first category is now reasonably understood. The dissolved salts, especially refractory oxides, tend to deposit on the cool tip of the sampling cone. The clogging of the orifices reduces the ion flow into the ICP-MS, lowers the pressure in the first stage of ICP-MS, and enhances the level of metal oxide ions. Because the extent of the clogging increases with the time, the signal drifts down. Even at the very early stage of the development of ICP-MS, matrix effects had been observed. Houk et al. found out that the ICP-MS was not tolerant to solutions containing significant amounts of dissolved solids.
Date: July 7, 1995
Creator: Chen, Xiaoshan
Partner: UNT Libraries Government Documents Department

Measurement of radionuclides using ion chromatography and flow-cell scintillation counting with pulse shape discrimination

Description: Principal conclusions are: CsI(Tl) provides sufficient pulse shape discrimination for use in the flow-cell detector. However, an improved method of coating is needed to extend the useful life of a detection cell. Of the activation/fission products investigated, only the co-elution of {sup 137}Cs and {sup 63}Ni produced a radiological interference. Tritium (and presumably other non-ionic radioisotopes) can be separated during the loading of the solution onto the pre- concentration column. Natural U (and/or decay products) produced a radiological interference with {sup 90}Sr. This is a potential problem. No potential radiological interferences were observed with {sup 223}Th. Chemical interferences were observed to some degree for all the chemicals tested except for the chloride solutions, NaCl and KCl, and the sulfate solution, Na{sub 2}SO{sub 4}. The specific interference effects were decreased detection efficiencies and changes in peak elution times. The NEL`s (non-observable effects loadings) are tentative targets for development of sample processing protocols, which is the next phase of the work.
Date: December 31, 1996
Creator: DeVol, T.A.; Fjeld, R.A.; Roane, J.E.; Leyba, J.D. & Branton, S.D.
Partner: UNT Libraries Government Documents Department

Improved separation techniques for the characterization of radioactive waste samples

Description: Analysts have routinely used organic solvent extractions and precipitation techniques to remove matrix constituents which interfere with the characterization of radioactive waste samples. Problems with these traditional techniques involve the production of organic waste and time consuming steps. Extraction chromatography using recently developed resins manufactured by Eichrom Industries provides accuracy comparable to traditional techniques while reducing waste and time. Three types of Eichrom resins were evaluated on samples from radioactive waste tanks at the Department of Energy`s (DOE) Oak Ridge National Laboratory (ORNL) for the analysis of the inorganic EPA target analyte elements, radioactive strontium, and radioactive technetium. Results show that extraction chromatography may be successfully applied to the characterization of DOE radioactive waste samples similar to those at ORNL, providing high efficiency, reduced waste production, and safety benefits.
Date: 1994
Creator: Meeks, A. M.; Keller, J. M.; Giaquinto, J. M. & Ross, T.
Partner: UNT Libraries Government Documents Department

CHARACTERISTICS OF ANODIC AND CORROSION FILMS ON ZIRCONIUM

Description: Zirconium anodizes similarly to tungsten in respect to the change of interference colors with applied voltage. However, the oxide layer on tungsten cannot reach as great a thickness. Hafnium does not anodize in the same way as zirconium but is similar to tantalum. By measuring the interference color and capacitative thicknesses on zirconium (Grades I and III) and a 2.5 wt.% tin ailoy, the film was found to grow less rapidly in terms of capacitance than in terms of iaterference colors. This was interpreted to mean that cracks develop in the oxide as it thickens. The effect was most pronounced on Grade III zirconium and least pronounced on the tin alloy. The reduction in capacitative thickness was especially noticeable when white oxide appeared. Comparative measurements on Grade I zirconium and 2.5 wt.% tin alloy indicated that the thickness of the oxide film on the tin alloy (after 16 hours in water) increased more rapidly with temperature than the film on zirconium. Tin is believed to act in ways to counteract the tendency of the oxide to form cracks, and to produce vacancies which promote ionic diffusion. (auth)
Date: May 1960
Creator: Misch, R. D.
Partner: UNT Libraries Government Documents Department

BERYLLIUM MEASUREMENT IN COMMERCIALLY AVAILABLE WET WIPES

Description: Analysis for beryllium by fluorescence is now an established method which is used in many government-run laboratories and commercial facilities. This study investigates the use of this technique using commercially available wet wipes. The fluorescence method is widely documented and has been approved as a standard test method by ASTM International and the National Institute for Occupational Safety and Health (NIOSH). The procedure involves dissolution of samples in aqueous ammonium bifluoride solution and then adding a small aliquot to a basic hydroxybenzoquinoline sulfonate fluorescent dye (Berylliant{trademark} Inc. Detection Solution Part No. CH-2) , and measuring the fluorescence. This method is specific to beryllium. This work explores the use of three different commercial wipes spiked with beryllium, as beryllium acetate or as beryllium oxide and subsequent analysis by optical fluorescence. The effect of possible interfering metals such as Fe, Ti and Pu in the wipe medium is also examined.
Date: February 18, 2011
Creator: Youmans-Mcdonald, L.
Partner: UNT Libraries Government Documents Department

Development and testing of a SREX flowsheet for the partitioning of strontium and lead from simulated ICPP sodium-bearing waste

Description: Laboratory experimentation has indicated that the SREX process is effective for partitioning {sup 90}Sr from acidic radioactive waste solutions located at the Idaho Chemical Processing Plant. Previous countercurrent flowsheet testing of the SREX process with simulated waste resulted in 99.98% removal of Sr. With this previous test, however, Pb was extracted by the SREX solvent and was not back-extracted in the dilute nitric acid strip section. The Pb concentration increased in the recycled solvent and in the aqueous phase of the strip section, resulting in the formation of a Pb precipitate. Subsequently, studies were initiated to identify alternative stripping agents which will selectively strip Sr and Pb from the SREX solvent. Based on the results of these studies, a countercurrent flow sheet was developed and tested in the 5.5-cm Centrifugal Contactor Mockup using simulated waste. The flowsheet tested consisted of an extraction section (0.15 M 4{prime},4{prime}(5)-di-(tert-butyldicyclohexo)-18-crown-6 and 1.2 M TBP in Isopar-L{reg_sign}), a 0.05 M nitric acid strip section for the removal of Sr from the SREX solvent, a 0.1 M ammonium citrate strip section for the removal of Pb from the SREX solvent, and a 2.0 M nitric acid equilibration section. The behavior of Sr, Pb, Al, Ca, Hg, Na, Zr, and H{sup +} was evaluated. The described flowsheet successfully extracted and selectively stripped Sr and Pb from the SBW simulant. Removal efficiencies of 97.9% and 99.91% were obtained for Sr and Pb, respectively. Essentially all of the extracted Sr (99.998%) and 1.9% of extracted Pb exited with the 0.05 M nitric acid strip product; whereas, 0.002% of the extracted Sr and 97.9% of the extracted Pb existed with the 0.1 M ammonium citrate strip product. Also, 95% of the Hg and 63% of the Zr were extracted by the SREX solvent.
Date: November 1, 1996
Creator: Law, J.D. & Wood, D.J.
Partner: UNT Libraries Government Documents Department

Design of benign matrix drums for the non-destructive assay performance demonstration program for the National TRU Program

Description: Regulatory compliance programs associated with the Department of Energy (DOE) Waste Isolation Pilot Plant (WIPP) Transuranic (TRU) Waste Characterization Program (the Program) require the collection of waste characterization data of known quality to support repository performance assessment, permitting, and associated activities. Blind audit samples, referred to as PDP (performance demonstration program) samples, are devices used in the NDA PDP program to acquire waste NDA system performance data per defined measurement routines. As defined under the current NDA PDP Program Plan, a PDP sample consists of a DOT 17C 55-gallon PDP matrix drum configured with insertable radioactive standards, working reference materials (WRMs). The particular manner in which the matrix drum and PDP standard(s) are combined is a function of the waste NDA system performance test objectives of a given cycle. The scope of this document is confined to the design of the PDP drum radioactive standard internal support structure, the matrix type and the as installed configuration. The term benign is used to designate a matrix possessing properties which are nominally non-interfering to waste NDA measurement techniques. Measurement interference sources are technique specific but include attributes such as: high matrix density, heterogeneous matrix distributions, matrix compositions containing high moderator/high Z element concentrations, etc. To the extent practicable the matrix drum design should not unduly bias one NDA modality over another due to the manner in which the matrix drum configuration manifests itself to the measurement system. To this end the PDP matrix drum configuration and composition detailed below is driven primarily by the intent to minimize the incorporation of matrix attributes known to interfere with fundamental waste NDA modalities, i.e. neutron and gamma based techniques.
Date: September 1, 1996
Creator: Becker, G.K.
Partner: UNT Libraries Government Documents Department

Evaluation and testing of HUMASORB-CS{trademark} for the removal of radionuclides from groundwater

Description: An independent experiment to demonstrate the combined removal of the radionuclides, {sup 85}Sr and {sup 137}Cs from groundwater has been conducted with the sorbent, HUMASORB-CS. Arctech, Inc. manufactures this humic acid-based sorbent material. This sorbent material is reported to have potential for remediation of contaminated groundwater present at DOE sites. The purpose of this work was to evaluate the removal efficiency and the capacity of the sorbent. Two ion-exchange columns were assembled at the Idaho Chemical Processing Plant (ICPP) to evaluate the sorbent technology. Initial {sup 137}Cs breakthrough in both columns was observed after 22.0 and 30.2 bed volumes, respectively. Strontium-85 removal was slightly more efficient than {sup 137}Cs removal. Initial {sup 85}Sr breakthrough in both columns was observed after 29.4 and 22.7 bed volumes, respectively. Calcium, which is of concern, is the major constituent within the feed solution. Calcium is attributed to loading interference in addition to other alkaline and alkaline earth metals such as stable Sr, Mg, Na, K, and Ba. Interfering ions fill exchange sites that greatly reduce the sorbents efficiency to sorb targeted ions such as radioactive Cs and Sr. Despite high concentrations of Ca in the feed solution, Ca was not sorbed by HUMASORB-CS. Results indicate HUMASORB-CS does not sorb sodium or potassium. Sodium and potassium concentrations were consistently observed at 100% breakthrough throughout the test.
Date: January 1, 1998
Creator: Mann, N.R.; Todd, T.A. & Wood, D.J.
Partner: UNT Libraries Government Documents Department

AMERICIUM SEPARATIONS FROM NITRIC ACID PROCESS EFFLUENT STREAMS

Description: The aging of the US nuclear stockpile presents a number of challenges, including the ever-increasing radioactivity of plutonium residues from {sup 241}Am. Minimization of this weak gamma-emitter in process and waste solutions is desirable to reduce both worker exposure and the effects of radiolysis on the final waste product. Removal of americium from plutonium nitric acid processing effluents, however, is complicated by the presence of large.quantities of competing metals, particularly Fe and Al, and-strongly oxidizing acidic solutions. The reprocessing operation offers several points at which americium removal maybe attempted, and we are evaluating two classes of materials targeted at different steps in the process. Extraction chromatography resin materials loaded with three different alkylcarbamoyl phosphinates and phosphine oxides were accessed for Am removal efficiency and Am/Fe selectivity from 1-7 molar nitric acid solutions. Commercial and experimental mono- and bifunctional anion-exchange resins were evaluated for total alpha-activity removal from post-evaporator solutions whose composition, relative to the original nitric acid effluent, is reduced in acid and greatly increased in total salt content. With both classes of materials, americium/total alpha emission removal is sufficient to meet regulatory requirements even under sub-optimal conditions. Batch distribution coefficients, column performance data, and the effects of Fe-masking agents will be presented.
Date: August 1, 2000
Creator: BARR, M.; JARVINEN, G. & AL, ET
Partner: UNT Libraries Government Documents Department

Potential corrosion and degradation mechanisms of Zircaloy cladding on spent nuclear fuel in a tuff repository

Description: A literature review and analysis were made of corrosion and degradation processes applicable to Zircaloy cladding on spent nuclear fuel in a tuff repository. In particular, lifetime sought for the Zircaloy is 10,000 years. Among the potential failure mechanisms examined were: oxidation by steam, air, and water, including the effects of ions whose presence is anticipated in the water; mechanical overload; stress (creep) rupture; stress-corrosion cracking (SCC); and delayed failure due to hydride cracking. The conclusion is that failure due to oxidation is not credible, although a few experiments are suggested to confirm the effect of aqueous fluoride on the Zircaloy cladding. Mechanical overload is not a problem, and failure from stress-rupture does not appear likely based on a modified Larson-Miller analysis. Analysis shows that delayed hydride cracking is not anticipated for the bulk of spent fuel pins. However, for a minority of pins under high stress, there is some uncertainty in the analysis as a result of: (1) uncertainty about crack depths in spent fuel claddings and (2) the effect of slow cooling on the formation of radially oriented hydride precipitates. Experimental resolution is called for. Finally, insufficient information is currently available on stress-corrosion cracking. While evidence is presented that SCC failure is not likely to occur, it is difficult to demonstrate this conclusively because the process is not clearly understood and data are limited. Further experimental work on SCC susceptibility is especially needed.
Date: September 1, 1984
Creator: Rothman, A.J.
Partner: UNT Libraries Government Documents Department

Multi-Window Classical Least Squares Multivariate Calibration Methods for Quantitative ICP-AES Analyses

Description: The advent of inductively coupled plasma-atomic emission spectrometers (ICP-AES) equipped with charge-coupled-device (CCD) detector arrays allows the application of multivariate calibration methods to the quantitative analysis of spectral data. We have applied classical least squares (CLS) methods to the analysis of a variety of samples containing up to 12 elements plus an internal standard. The elements included in the calibration models were Ag, Al, As, Au, Cd, Cr, Cu, Fe, Ni, Pb, Pd, and Se. By performing the CLS analysis separately in each of 46 spectral windows and by pooling the CLS concentration results for each element in all windows in a statistically efficient manner, we have been able to significantly improve the accuracy and precision of the ICP-AES analyses relative to the univariate and single-window multivariate methods supplied with the spectrometer. This new multi-window CLS (MWCLS) approach simplifies the analyses by providing a single concentration determination for each element from all spectral windows. Thus, the analyst does not have to perform the tedious task of reviewing the results from each window in an attempt to decide the correct value among discrepant analyses in one or more windows for each element. Furthermore, it is not necessary to construct a spectral correction model for each window prior to calibration and analysis: When one or more interfering elements was present, the new MWCLS method was able to reduce prediction errors for a selected analyte by more than 2 orders of magnitude compared to the worst case single-window multivariate and univariate predictions. The MWCLS detection limits in the presence of multiple interferences are 15 rig/g (i.e., 15 ppb) or better for each element. In addition, errors with the new method are only slightly inflated when only a single target element is included in the calibration (i.e., knowledge of all other elements is excluded ...
Date: October 1999
Creator: Chambers, William B.; Haaland, David M.; Keenan, Michael R. & Melgaard, David K.
Partner: UNT Libraries Government Documents Department

Determination of low-level mercury by cold vapor generation and atomic absorption spectroscopy

Description: A procedure for determining mercury in liquid samples by cold vapor flameless atomic absorption spectroscopy was developed. The optimum parameter values were determined and mercury standard storage conditions investigated. The effect and tolerance levels of twenty-seven ions, including those ions common to Tank Farm Operations and the Synthetic Wastes, were measured. Standard deviation for the procedure is less than 1%. The procedure can be used to determine mercury at the part per billion level in any liquid sample, a thousand-fold increase in sensitivity over current flame techniques.
Date: June 1, 1977
Creator: King, A.D.
Partner: UNT Libraries Government Documents Department

EQUILIBRIUM CALCULATION IN THE SYSTEM: URANYL NITRATE, NITRIC ACID, WATER, TBP, AND KEROSENE DILUENT USING THE ORACLE DIGITAL COMPUTER

Description: A set of equations was written which allowed the calculation of equilibrium concentrations in the solvent phase of nitric acid and uranyl nitrate, given the initial TBP concentration in the solvent and the aqueous phase concentrations of acid and uranium. An ORACLE subroutine was written based on these equations which will calculate a set of equilibrium values in about 35 milliseconds. The subroutine was incorporated into a short program to calculate equilibrium points. A set of calculated points are presented in graphical form for 5, up to 7 M and uranyl nitrate concentrations up to 0.6 M in the aqueous phase. Since these calculations were based on limited data, it is the purpose of this memo to invite comment on their accuracy. The equations were reworked from a Russian paper by A. M. Rozen and L. P. Khorkhorina, using emperical polynomial fits for some poorly defined parameters, and were based principally on data from J. W. Codding. This project was undertaken to provide a subroutine to calculate equilibria in a general purpose ORACLE program to calculate the performance of multi-stage compound extraction cascades with more than one significant solute. (auth)
Date: August 12, 1959
Creator: Jury, S.H. & Whatley, M.E.
Partner: UNT Libraries Government Documents Department

Characterization of Group V Dubnium Homologs on DGA Extraction Chromatography Resin from Nitric and Hydrofluoric Acid Matrices

Description: Studies of the chemical properties of superheavy elements (SHE) pose interesting challenges due to their short half-lives and low production rates. Chemical systems must have extremely fast kinetics, fast enough kinetics to be able to examine the chemical properties of interest before the SHE decays to another nuclide. To achieve chemistry on such time scales, the chemical system must also be easily automated. Most importantly however, a chemical system must be developed which provides suitable separation and kinetics before an on-line study of a SHE can be performed. Relativistic effects make studying the chemical properties of SHEs interesting due to the impact these effects could have on the SHEs chemical properties. Relativistic effects arise when the velocity of the s orbital electrons approach the speed of light. As this velocity increases, the Bohr radius of the inner electron orbitals decreases and there is an increase in the particles mass. This contraction results in a destabilization of the energy of the outer d and f electron orbitals (5f and 6d in the case of SHE), which can cause these to expand due to their increased shielding from the nuclear charge. Another relativistic effect is the spin-orbit splitting for p, d, and f orbitals into j = 1 {+-} 1/2 states. This can lead most interestingly to a possible increased stability of element 114, which due to large spin-orbit splitting of the 7p orbital and the relativistically stabilized 7p{sub 1/2} and 7s orbital gives rise to a closed shell ground state of 7s{sup 2}7p{sub 1/2}{sup 2}. The homologs of element 105, dubnium (Db), Ta and Nb and the pseudo-homolog Pa, are well known to hydrolyze and form both neutral and non-neutral monoatomic and polyatomic species that may cause issues with extraction from a given chemical system. Early ion-exchange and solvent-extraction studies show ...
Date: February 21, 2012
Creator: Despotopulos, J D & Sudowe, R
Partner: UNT Libraries Government Documents Department

INVESTIGATION OF THE TOTAL ORGANIC HALOGEN ANALYTICAL METHOD AT THE WASTE SAMPLING AND CHARACTERIZATION FACILITY

Description: Total organic halogen (TOX) is used as a parameter to screen groundwater samples at the Hanford Site. Trending is done for each groundwater well, and changes in TOX and other screening parameters can lead to costly changes in the monitoring protocol. The Waste Sampling and Characterization Facility (WSCF) analyzes groundwater samples for TOX using the United States Environmental Protection Agency (EPA) SW-S46 method 9020B (EPA 1996a). Samples from the Soil and Groundwater Remediation Project (SGRP) are submitted to the WSCF for analysis without information regarding the source of the sample; each sample is in essence a ''blind'' sample to the laboratory. Feedback from the SGRP indicated that some of the WSCF-generated TOX data from groundwater wells had a number of outlier values based on the historical trends (Anastos 200Sa). Additionally, analysts at WSCF observed inconsistent TOX results among field sample replicates. Therefore, the WSCF lab performed an investigation of the TOX analysis to determine the cause of the outlier data points. Two causes were found that contributed to generating out-of-trend TOX data: (1) The presence of inorganic chloride in the groundwater samples: at inorganic chloride concentrations greater than about 10 parts per million (ppm), apparent TOX values increase with increasing chloride concentration. A parallel observation is the increase in apparent breakthrough of TOX from the first to the second activated-carbon adsorption tubes with increasing inorganic chloride concentration. (2) During the sample preparation step, excessive purging of the adsorption tubes with oxygen pressurization gas after sample loading may cause channeling in the activated carbon bed. This channeling leads to poor removal of inorganic chloride during the subsequent wash step with aqueous potassium nitrate. The presence of this residual inorganic chloride then produces erroneously high TOX values. Changes in sample preparation were studied to more effectively remove inorganic chloride from the activated-carbon ...
Date: February 13, 2009
Creator: DOUGLAS, JG; HK MEZNARICH, PHD; OLSEN, JR; PHD, GA ROSS & STAUFFER, M
Partner: UNT Libraries Government Documents Department