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Review and evaluation of extractants for strontium removal using magnetically assisted chemical separation

Description: A literature review on extractants for strontium removal was initially performed at Northern Illinois University to assess their potential in magnetically assisted chemical separation. A series of potential strontium extractants was systematically evaluated there using radioanalytical methods. Initial experiments were designed to test the uptake of strontium from nitric acid using several samples of magnetic extractant particles that were coated with various crown ether ligands. High partition coefficient (K{sub d}) values for stimulant tank waste were obtained. Further studies demonstrated that the large partitioning was due to uncoated particles.
Date: November 1, 1995
Creator: Bauer, C.B.; Rogers, R.D.; Nunez, L.; Ziemer, M.D.; Pleune, T.T. & Vandegrift, G.F.
Partner: UNT Libraries Government Documents Department

Radium separation through complexation by aqueous crown ethers and ion exchange or solvent extraction

Description: The effect of three water-soluble, unsubstituted crown ethers (15-crown-5 (15C5), 18-crown-6 (18C6) and 21-crown-7 (21C7)) on the uptake of Ca, Sr, Ba and Ra cations by a sulfonic acid cation exchange resin, and on the extraction of the same cations by xylene solutions of dinonylnaphthalenesulfonic acid (HDNNS) from aqueous hydrochloric acid solutions has been investigated. The crown ethers enhance the sorption of the larger cations by the ion exchange resin, thereby improving the resin selectivity over calcium, a result of a synergistic interaction between the crown ether and the ionic functional groups of the resin. Similarly, the extraction of the larger alkaline earth cations into xylene by HDNNS is strongly synergized by the presence of the crown ethers in the aqueous phase. Promising results for intra-Group IIa cation separations have been obtained using each of the three crown ethers as the aqueous ligands and the sulfonic acid cation exchange resin. Even greater separation factors for the radium-calcium couple have been measured with the crown-ethers and HDNNS solutions in the solvent extraction mode. The application of the uptake and extraction results to the development of radium separation schemes is discussed and a possible flowchart for the determination of {sup 226}Ra/{sup 228}Ra in natural waters is presented.
Date: November 1, 1997
Creator: Chiarizia, R.; Dietz, M.L.; Horwitz, E.P. & Burnett, W.C.
Partner: UNT Libraries Government Documents Department

Behavior of nuclear waste elements during hydrothermal alteration of glassy rhyolite in an active geothermal system: Yellowstone National Park, Wyoming

Description: The behavior of a group of nuclear waste elements (U, Th, Sr, Zr, Sb, Cs, Ba, and Sm) during hydrothermal alteration of glassy rhyolite is investigated through detailed geochemical analyses of whole rocks, glass and mineral separates, and thermal waters. Significant mobility of U, Sr, Sb, Cs, and Ba is found, and the role of sorption processes in their observed behavior is identified. Th, Zr, and Sm are relatively immobile, except on a microscopic scale. 9 references, 2 figures, 2 tables.
Date: December 31, 1984
Creator: Sturchio, N.C. & Seitz, M.G.
Partner: UNT Libraries Government Documents Department

Human radiation studies: Remembering the early years. Oral history of Dr. George Voelz, M.D., November 29, 1994

Description: Dr. George Voelz was interviewed by representatives of the US DOE Office of Human Radiation Experiments (OHRE). This oral history covers Dr. Voelz`s research on Manhattan Engineering District plutonium workers, the acute and long term effects of radiation, his inhalation studies, and his activities at the 1961 INL reactor accident (SL-1 Reactor). After a brief biographical sketch, Dr. Voelz his remembrances on tissue studies of plutonium workers, the plutonium injection studies of 1945-1946, the controlled environmental radioiodine tests of 1963-1968, and tracer studies with human volunteers at Los Alamos. Dr. Voelz states his opinions concerning misconceptions about the Los Alamos Human Radiation Experiments.
Date: May 1, 1995
Partner: UNT Libraries Government Documents Department

Fast neutron radiography research at ANL-W

Description: Thirty-seven different elements were tested for their suitability as converter screens for direct and indirect fast neutron radiography. The use of commercial X-ray scintillator screens containing YTaO{sub 4}, LaOBr:Tm, YTaO{sub 4}:Nb, YTaO{sub 4}:Tm, CaWO{sub 4}, BaSO{sub 4}:Sr, and GdO{sub 2}S:Tb was also explored for direct fast neutron radiography. For the indirect radiographic process, only one element, holmium, was found to be better than copper. Iron was also found to work as well as copper. All other elements that were tested were inferior to copper for indirect fast neutron radiography. For direct fast neutron radiography, the results were markedly different. Copper was found to be a poor material to sue, as thirty-two of the elements performed better than the copper. Tantalum was found to be the best material to use. Several other materials that also performed remarkably well include, in order of decreasing utility, gold, lutetium, germanium, dysprosium, and thulium. Several interesting results were obtained for the commercial X-ray scintillator screens. Most notably, useful radiographs were produced with all of the various scintillation screens. However, the screens containing YTaO{sub 4}:Nb offered the greatest film densities for the shortest exposure times. Screens using GdSO{sub 4}:Tb provided the best resolution and clearest images at the sacrifice of exposure time. Also, as previous researchers found, scintillator screens offered significantly shorter exposure times than activation foils.
Date: June 1, 1996
Creator: Klann, R.T. & Natale, M.D.
Partner: UNT Libraries Government Documents Department

Batch test equilibration studies examining the removal of Cs, Sr, and Tc from supernatants from ORNL underground storage tanks by selected ion exchangers

Description: Bench-scale batch equilibration tests have been conducted with supernatants from two underground tanks at the Melton Valley Storage Tank (MVST) Facility at Oak Ridge National Laboratory (ORNL) to determine the effectiveness of selected ion exchangers in removing cesium, strontium, and technetium. Seven sorbents were evaluated for cesium removal, nine for strontium removal, and four for technetium removal. The results indicate that granular potassium cobalt hexacyanoferrate was the most effective of the exchangers evaluated for removing cesium from the supernatants. The powdered forms of sodium titanate (NaTiO) and cystalline silicotitanate (CST) were superior in removing the strontium; however, for the sorbents of suitable particle size for column use, titanium monohydrogen phosphate (TiHP {phi}), sodium titanate/polyacrylonitrile (NaTiO-PAN), and titanium monohydrogen phosphate/polyacrylonitrile (TiP-PAN) gave the best results and were about equally effective. Reillex{trademark} 402 was the most effective exchanger in removing the technetium; however, it was only slightly more satisfactory than Reillex{trademark} HPQ.
Date: June 1, 1995
Creator: Collins, J.L.; Egan, B.Z.; Anderson, K.K.; Chase, C.W. & Bell, J.T.
Partner: UNT Libraries Government Documents Department

1993 to 1995 environmental surveillance data collected at or near Area G

Description: This report summarizes Environmental Surveillance data collected by the Water Quality and Hydrology Group during 1993, 1994, and 1995 at or in the vicinity of TA-54, Area-G of the Los Alamos National Laboratory, New Mexico. The summary includes radiochemical, metals, general inorganic, and organic analytical results. The tables list measured concentrations (or detection limits for results below detection limits), analytical uncertainties for radiochemical data, sample locations, and sample dates. A map showing sample locations is also included. Preparation of this report was funded by the Solid Waste Management Group (CST-14) in support of the Waste Management Program.
Date: September 1, 1996
Creator: Mullen, K.; Collins, S. & Rogers, D.
Partner: UNT Libraries Government Documents Department

Geochemistry studies pertaining to the G-tunnel radionuclide migration field experiment

Description: This report presents the results of geochemical studies of Tunnel Bed tuff that were performed by Los Alamos National Laboratory or done at its direction as part of the Nevada Test Site G-Tunnel Radionuclide Migration Field Experiment. A tuff-treated water was prepared and used in laboratory-scale measurements of radionuclide sorption onto crushed Tunnel Bed tuff, pulverized fracture-fill material, tuff wafers, and a solid tuff core. Modelling studies were undertaken to determine the effects of matrix diffusion and unsaturated tuff on the proposed fracture-flow experiments. The initial results of those studies are presented in this report.
Date: November 1, 1982
Creator: Norris, A.E.; Aguilar, R.D. & Bayhurst, B.P.
Partner: UNT Libraries Government Documents Department

Leaching of actinide-doped nuclear waste glass in a tuff-dominated system

Description: A laboratory leaching test has been performed as part of a project to evaluate the suitability of tuff rocks at Yucca Mountain, Nevada, as a site for a high-level nuclear waste repository. Glass samples were placed in water inside tuff vessels, and then the tuff vessels were placed in water inside Teflon containers. Glass-component leach rates and migration through the tuff were measured for samples of the ATM-8 actinide glass, which is a PNL 76-68 based glass doped with low levels of {sup 99}Tc, {sup 237}Np, {sup 238}U, and {sup 239}Pu to simulate wastes. Disc samples of this glass were leached at 90{sup 0}C for 30, 90, and 183 days inside tuff vessels using a natural groundwater (J-13 well-water) as the leachant. At the end of each leaching interval, the J-13 water present inside and outside the rock vessel was analyzed for glass components in solutions. Boron, molybdenum, and technetium appear to migrate through the rock at rates that depend on the porosity of each vessel and the time. The actinide elements were found only in the inner leachate. Normalized elemental mass loss values for boron, molybdenum, and technetium were calculated using concentrations of the inner and outer leachates and assuming a negligible retention on the rock. The maximum normalized release was 2.3 g/m{sup 2} for technetium. Boron, molybdenum, technetium, and neptunium were released linearly with respect to each other, with boron and molybdenum released at about 85% of the technetium rate, and neptunium at 5 to 10% of the technetium rate. Plutonium was found at low levels in the inner leachate but was strongly sorbed on the steel and Teflon supports. Neptunium was sorbed to a lesser extent. 8 refs., 6 figs., 6 tabs.
Date: January 1, 1987
Creator: Bazan, F.; Rego, J. & Aines, R.D.
Partner: UNT Libraries Government Documents Department

Modeling ion exchange in clinoptilolite using the EQ3/6 geochemical modeling code

Description: Assessing the suitability of Yucca Mtn., NV as a potential repository for high-level nuclear waste requires the means to simulate ion-exchange behavior of zeolites. Vanselow and Gapon convention cation-exchange models have been added to geochemical modeling codes EQ3NR/EQ6, allowing exchange to be modeled for up to three exchangers or a single exchanger with three independent sites. Solid-solution models that are numerically equivalent to the ion-exchange models were derived and also implemented in the code. The Gapon model is inconsistent with experimental adsorption isotherms of trace components in clinoptilolite. A one-site Vanselow model can describe adsorption of Cs or Sr on clinoptilolite, but a two-site Vanselow exchange model is necessary to describe K contents of natural clinoptilolites.
Date: June 1, 1992
Creator: Viani, B.E. & Bruton, C.J.
Partner: UNT Libraries Government Documents Department

Ion sorption onto hydrous ferric oxides: Effect on major element fluid chemistry at Aspo, Sweden

Description: The observed variability of fluid chemistry at the Aespoe Hard Rock Laboratory is not fully described by conservative fluid mixing models. Ion exchange may account for some of the observed discrepancies. It is also possible that variably charged solids such as oxyhydroxides of Fe can serve as sources and sinks of anions and cations through surface complexation. Surface complexation reactions on hydrous ferric oxides involve sorption of both cations and anions. Geochemical modeling of the surface chemistry of hydrous ferric oxides (HFOs) in equilibrium with shallow HBH02 and deep KA0483A waters shows that HFOs can serve as significant, pH-sensitive sources and sinks for cations and anions. Carbonate sorption is favored especially at below-neutral pH. A greater mass of carbonate is sorbed onto HFO surfaces than is contained in the fluid when 10 g goethite, used as a proxy for HFOs, is in contact with 1 kg H{sub 2}O. The masses of sorbent required to significantly impact fluid chemistry through sorption/desorption reactions seem to be reasonable when compared to the occurrences of HFOs at Aespoe. Thus, it is possible that small changes in fluid chemistry can cause significant releases of cations or anions from HFOs into the fluid phase or, alternately, result in uptake of aqueous species onto HFO surfaces. Simulations of the mixing of shallow HBH02 and native KA0483A waters in the presence of a fixed mass of goethite show that surface complexation does not cause the concentrations of Ca, Sr, and SO{sub 4} to deviate from those that are predicted using conservative mixing models. Results for HCO{sub 3} are more difficult to interpret and cannot be addressed adequately at this time.
Date: June 1, 1996
Creator: Bruton, C.J. & Viani, B.E.
Partner: UNT Libraries Government Documents Department

Protocols of radiocontaminant air monitoring for inhalation exposure estimates

Description: Monitoring the plutonium and americium particle emissions from soils contaminated during atmospheric nuclear testing or due to accidental releases is important for several reasons. First, it is important to quantify the extent of potential human exposure from inhalation of alpha-emitting particles, which is the major exposure pathway from transuranic radionuclides. Second, the information provided by resuspension monitoring is the basis of criteria that determine the target soil concentrations for management and cleanup of contaminated soil sites. There are other radioactive aerosols, such as the fission products (cesium and strontium) and neutron-activation products (europium isotopes), which may be resuspended and therefore necessary to monitor as well. This Standard Protocol (SP) provides the method used for radiocontaminant air monitoring by the Health and Ecological Assessment Division (formerly Environmental Sciences Division), Lawrence Livermore National Laboratory, as developed and tested at Nevada Test Site (NTS) and in the Marshall Islands. The objective of this SP is to document the applications and methods of monitoring of all the relevant variables. This protocol deals only with measuring air concentrations of radionuclides and total suspended particulates (TSP, or {open_quotes}dust{close_quotes}). A separate protocol presents the more difficult measurements required to determine transuranic aerosol emission rates, or {open_quotes}resuspension rate{close_quotes}.
Date: September 1, 1995
Creator: Shinn, J.H.
Partner: UNT Libraries Government Documents Department

Solubility limits on radionuclide dissolution

Description: This paper examines the effects of solubility in limiting dissolution rates of a number of important radionuclides from spent fuel and high-level waste. Two simple dissolution models were used for calculations that would be characteristics of a Yucca Mountain repository. A saturation-limited dissolution model, in which the water flowing through the repository is assumed to be saturated with each waste element, is very conservative in that it overestimates dissolution rates. A diffusion-limited dissolution model, in which element-dissolution rates are limited by diffusion of waste elements into water flowing past the waste, is more realistic, but it is subject to some uncertainty at this time. Dissolution rates of some elements (Pu, Am, Sn, Th, Zr, Sm) are always limited by solubility. Dissolution rates of other elements (Cs, Tc, Np, Sr, C, I) are never solubility limited; their release would be limited by dissolution of the bulk waste form. Still other elements (U, Cm, Ni, Ra) show solubility-limited dissolution under some conditions. 9 references, 3 tables.
Date: December 31, 1984
Creator: Kerrisk, J.F.
Partner: UNT Libraries Government Documents Department

Groundwater chemistry along flow paths between a proposed repository site and the accessible environment

Description: The Nevada Nuclear Waste Storage Investigations Program of the Department of Energy is investigating Yucca Mountain in the Nevada Test Site as a possible repository location. As part of this investigation, the groundwater from all pumped wells in and near the site has been sampled and analyzed; the results are reported in this document. The speciation and solubility of nuclear waste elements in these groundwaters have been calculated using the EQ3/6 computer code. Estimates have also been made of the pH and Eh buffering capacity of the water/rock system of Yucca Mountain.
Date: November 1, 1984
Creator: Ogard, A.E. & Kerrisk, J.F.
Partner: UNT Libraries Government Documents Department

Laser-induced breakdown spectroscopy for the real-time analysis of mixed waste samples containing Sr

Description: In this report, the use of Laser-induced breakdown spectroscopy to analyze mixed waste samples containing Sr is discussed. The mixed waste samples investigated include vitrified waste glass and contaminated soil. Compared to traditional analysis techniques, the laser-based method is fast (i.e., analysis times on the order of minutes) and essentially waste free since little or no sample preparation is required. Detection limits on the order of pmm Sr were determined. Detection limits obtained using a fiber optic cable to deliver laser pulses to soil samples containing Cr, Zr, Pb, Be, Cu, and Ni will also be discussed.
Date: May 1, 1995
Creator: Barefield, J.E. II; Koskelo, A.C.; Multari, R.A.; Cremers, D.A.; Gamble, T.K. & Han, C.Y.
Partner: UNT Libraries Government Documents Department

Strontium concentrations in chamisa (Chrysothamnus nauseosus) shrub plants growing in a former liquid waste disposal area in Bayo Canyon

Description: Chamisa (Chrysothamnus nauseosus) shrub plants growing in a former liquid waste disposal site Solid Waste Management Unit [SWMU] 10-003(c) in Bayo Canyon at Los Alamos National Laboratory (LANL) were collected and analyzed for strontium ({sup 90}Sr) and total uranium. Surface soil samples were also collected from below (understory) and between (interspace) shrub canopies. Both chamisa plants growing over SWMU 10-003(c) contained significantly higher concentrations of {sup 90}Sr than a control plant -- one plant, in particular, contained 90, 500 pCi {sup 90}Sr g{sup {minus}1} ash in top-growth material. Similarly, soil surface samples collected underneath and between plants contained {sup 90}Sr concentrations above background and LANL screening action levels; this probably occurred as a result of chamisa plant leaf fall contaminating the soil understory area followed by water and/or winds moving {sup 90}Sr to the soil interspace area. Although some soil surface migration of {sup 90}Sr from SWMU 10-003(c) has occurred, the level of {sup 90}Sr in sediments collected downstream of SWMU 10-003(c) at the Bayo Canyon/State Road 5 intersection was still within regional (background) concentrations.
Date: November 1, 1995
Creator: Fresquez, P.R.; Foxx, T.S. & Naranjo, L. Jr.
Partner: UNT Libraries Government Documents Department

Assessment of the important radionuclides in nuclear waste

Description: The relative importance of the various radionuclides contained in nuclear waste has been assessed by consideration of (1) the quantity of each radionuclide present, (2) the Environmental Protection Agency`s release limits for radionuclides, (3) how retardation processes such as solubility and sorption affect radionuclie transport, and (4) the physical and chemical forms of radionuclides in the waste. Three types of waste were reviewed: spent fuel, high-level waste, and defense high-level waste. Conditions specific to the Nevada Nuclear Waste Storage Investigations project potential site at Yucca Mountain were used to describe radionuclide transport. The actinides Am, Pu, Np, and U were identified as the waste elements for which solubility and sorption data were most urgently needed. Other important waste elements were identified as Sr, Cs, C, Ni, Zr, Tc, Th, Ra, and Sn. Under some conditions, radionuclides of three elements (C, Tc, and I) may have high solubility and negligible sorption. The potential for transport of some waste elements (C and I) in the gas phase must also be evaluated for the Yucca Mountain Site. 12 refs., 17 tabs.
Date: October 1, 1985
Creator: Kerrisk, J.F.
Partner: UNT Libraries Government Documents Department

Dependence of radionuclide sorption on sample grinding, surface area, and water composition

Description: In its 1987 technical position paper, ``Determination of Radionuclide Sorption for High-Level Nuclear Waste Repositories``, the Nuclear Regulatory Commission (NRC) review panel delineated several studies needed to show that experimental sorption coefficients could accurately model radionuclide sorption behavior along release pathways. In particular, they focused on the potential problems involved with the use of crushed rock samples, stating ``If crushed solids are used, it is essential to show that laboratory experiments involving sorption on crushed solids are relevant to the repository site. The surfaces of crushed material may be significantly different from the surfaces of intact material, both porous and fractured. Grinding may expose the surfaces of solid phases different from those which groundwater would contact in a repository and/or may change the reactivity of the same mineral surfaces with dissolved radionuclides. The surface of crushed minerals can be enriched in certain elements by factors of two and three relative to the bulk composition. The experiments reported here were performed in direct response to the NRC technical position paper.
Date: February 1993
Creator: Rogers, P. S. Z. & Meijer, A.
Partner: UNT Libraries Government Documents Department

Sorption and desorption of cesium and strontium on TA-2 and TA-41 soils and sediments

Description: Current environmental monitoring has detected radioactive contaminants in alluvial groundwater, soils, and sediments in the TA-2 and TA-41 areas along the north central edge of Los Alamos National Laboratory. Because of this contamination, this study was initiated. The objective of this study is to quantify the sorptivity of cesium and strontium onto TA-2 and TA-41 site specific soil samples under a controlled environment in the laboratory. The purposes of this work are to determine cesium and strontium sorption coefficient for these sit specific soils and to evaluate the potential transport of cesium and strontium. Based on this information, a risk assessment and remediation strategy can be developed.
Date: April 1, 1996
Creator: Kung, K. Stephen; Li, Benjamin W.; Longmire, P.A. & Fowler, M.M.
Partner: UNT Libraries Government Documents Department

Sorption-desorption studies on tuff III. A continuation of studies with samples from Jackass Flats and Yucca Mountain, Nevada

Description: This report is the third in a series of reports describing studies of sorption and migration of radionuclides in tuff. The investigations were extended to lithologies of tuff not previously studied. Continuing experiments with uranium, plutonium, and americium are described. The dependence of sorption on the concentration of the sorbing element and on the solution-to-solid ratio was investigated for a number of nuclides and two lithologies. A circulating system was designed for measuring sorption ratios. Values obtained from this system, batch measurements, and column elutions are compared. Progress on measuring and controlling Eh is described.
Date: May 1, 1981
Creator: Wolfsberg, K.; Aguilar, R.D. & Bayhurst, B.P.
Partner: UNT Libraries Government Documents Department

Evaluation of interim and final waste forms for the newly generated liquid low-level waste flowsheet

Description: The purpose of this review is to evaluate the final forms that have been proposed for radioactive-containing solid wastes and to determine their application to the solid wastes that will result from the treatment of newly generated liquid low-level waste (NGLLLW) and Melton Valley Storage Tank (MVST) supernate at the Oak Ridge National Laboratory (ORNL). Since cesium and strontium are the predominant radionuclides in NGLLLW and MVST supernate, this review is focused on the stabilization and solidification of solid wastes containing these radionuclides in cement, glass, and polymeric materials-the principal waste forms that have been tested with these types of wastes. Several studies have shown that both cesium and strontium are leached by distilled water from solidified cement, although the leachabilities of cesium are generally higher than those of strontium under similar conditions. The situation is exacerbated by the presence of sulfates in the solution, as manifested by cracking of the grout. Additives such as bentonite, blast-furnace slag, fly ash, montmorillonite, pottery clay, silica, and zeolites generally decrease the cesium and strontium release rates. Longer cement curing times (>28 d) and high ionic strengths of the leachates, such as those that occur in seawater, also decrease the leach rates of these radionuclides. Lower cesium leach rates are observed from vitrified wastes than from grout waste forms. However, significant quantities of cesium are volatilized due to the elevated temperatures required to vitrify the waste. Hence, vitrification will generally require the use of cleanup systems for the off-gases to prevent their release into the atmosphere.
Date: May 1, 1996
Creator: Abotsi, G.M.K.; Bostick, D.T. & Beck, D.E.
Partner: UNT Libraries Government Documents Department

Glass-Like Heat Conduction in Crystalline Semiconductors

Description: The thermal conductivity and structural properties of polycrystalline and single crystal semiconductor type-1 germanium clathrates are reported. Germanium clathrates exhibit thermal conductivities that are typical of amorphous materials. This behavior occurs in spite of their well-defined crystalline structure. The authors employ temperature dependent neutron diffraction data in investigating the displacements of the caged strontium atoms in Sr{sub 8}Ga{sub 16}Ge{sub 30} and their interaction with the polyhedral cages that entrap them. Their aim is to investigate the correlation between the structural properties and the low, glass-like thermal conductivity observed in this compound.
Date: June 13, 1999
Creator: Nolas, G.S.; Cohn, J.L.; Chakoumakos, B.C. & Slack, G.A.
Partner: UNT Libraries Government Documents Department