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Sample records for actinide region progress

  1. Neutron scattering studies in the actinide region. Progress report, December 1, 1985-July 30, 1986

    Research is reported in the following areas: (1) analysis of neutron elastic and inelastic scattering measurements on low-lying levels of actinide nuclei; (2) exploratory measurements of neutrons scattered inelastically from highly excited states in Th-232 and U-238 for incident energies above 2 MeV; (3) background and time-resolution studies of neutron detectors used in iron filter work at E/sub n/ = 82 keV; (4) improvements in accelerator operation

  2. Neutron scattering studies in the actinide region. Progress report, August 1, 1991--July 31, 1994

    During the period August 1, 1991 to July 31, 1994 the authors report progress on the following: (a) prompt fission neutron energy spectra for 235U and 239Pu; (b) two-parameter measurement of nuclear lifetimes; (c) 'black' neutron detector; (d) data reduction techniques for neutron scattering experiments; (e) elastic and inelastic neutron scattering studies in 197Au; (f) elastic and inelastic neutron scattering studies in 239Pu; (g) neutron induced defects in silicon dioxide MOS structures; (h) response of a 235U fission chamber near reaction thresholds; (i) efficiency calibration of a liquid scintillation detector using the WNR facility at LAMPF; (j) prompt fission neutron energy spectrum measurements below the incident neutron energy; (k) multi-parameter data acquisition system; (l) accelerator improvements; (m) non-DOE supported research. Eight Ph.D. dissertations and two M.S. theses were completed during the report period. Publications consisted of 6 journal articles, 10 conference proceedings, and 19 abstracts of presentations at scientific meetings. One invited talk was given

  3. Recent progress in actinide borate chemistry.

    Wang, Shuao; Alekseev, Evgeny V; Depmeier, Wulf; Albrecht-Schmitt, Thomas E

    2011-10-21

    The use of molten boric acid as a reactive flux for synthesizing actinide borates has been developed in the past two years providing access to a remarkable array of exotic materials with both unusual structures and unprecedented properties. [ThB(5)O(6)(OH)(6)][BO(OH)(2)]·2.5H(2)O possesses a cationic supertetrahedral structure and displays remarkable anion exchange properties with high selectivity for TcO(4)(-). Uranyl borates form noncentrosymmetric structures with extraordinarily rich topological relationships. Neptunium borates are often mixed-valent and yield rare examples of compounds with one metal in three different oxidation states. Plutonium borates display new coordination chemistry for trivalent actinides. Finally, americium borates show a dramatic departure from plutonium borates, and there are scant examples of families of actinides compounds that extend past plutonium to examine the bonding of later actinides. There are several grand challenges that this work addresses. The foremost of these challenges is the development of structure-property relationships in transuranium materials. A deep understanding of the materials chemistry of actinides will likely lead to the development of advanced waste forms for radionuclides present in nuclear waste that prevent their transport in the environment. This work may have also uncovered the solubility-limiting phases of actinides in some repositories, and allows for measurements on the stability of these materials. PMID:21915396

  4. Recent progress in actinide borate chemistry

    Wang, S.; Alekseev, E .V.; Depmeier, W.; Albrecht-Schmitt, T.E.

    2011-01-01

    The use of molten boric acid as a reactive flux for synthesizing actinide borates has been developed in the past two years providing access to a remarkable array of exotic materials with both unusual structures and unprecedented properties. [ThB(5)O(6)(OH)(6)][BO(OH)(2)]·2.5H(2)O possesses a cationic supertetrahedral structure and displays remarkable anion exchange properties with high selectivity for TcO(4)(-). Uranyl borates form noncentrosymmetric structures with extraordinarily rich topol...

  5. Fusion-driven actinide burner design study. Second quarterly progress report

    The Second Quarterly Progress Report summarizes the status at the mid-point of the conceptual design effort. The fusion driver continues to pose some of the principal design problems due to the necessity of advancing plasma engineering and technology for long pulse, high duty cycle operation. The development of credible design solutions to these problems is one of the major objectives of the study. The TF and OH coil designs have been modified to provide a more compact arrangement in the nose region of the TF coils and to ensure fully cryostable operation. A unique concept has been developed to effectively shield the TF coils from the poloidal fields. A vacuum vessel concept which separates the functions for sustaining the differential pressure load and for sealing the vacuum system is described. The thickness of the blanket has been decreased to reduce the power density and the actinide inventory. Determination and presentation of actinide depletion characteristics represents a major element thus far in the study and is a principal objective. Evaluation of the changes in the hazard only during irradiation proved to be an inadequate measure of the reduction in long term hazards due to the importance of radioactive daughter products which appear much later in time. Therefore, comparisons have been made of long term decay characteristics before and after irradiation in the actinide burner. It has also been noted that some of the actinides that are produced during irradiation have beneficial applications as radioisotopic power sources. These and other considerations suggest that alternate approaches to assessing the waste management problem be considered to develop a meaningful perspective on long term hazards from the actinides

  6. Fusion-driven actinide burner design study. Second quarterly progress report

    Chi, J.W.H.; Gold, R.E.; Holman, R.R.

    1975-11-01

    The Second Quarterly Progress Report summarizes the status at the mid-point of the conceptual design effort. The fusion driver continues to pose some of the principal design problems due to the necessity of advancing plasma engineering and technology for long pulse, high duty cycle operation. The development of credible design solutions to these problems is one of the major objectives of the study. The TF and OH coil designs have been modified to provide a more compact arrangement in the nose region of the TF coils and to ensure fully cryostable operation. A unique concept has been developed to effectively shield the TF coils from the poloidal fields. A vacuum vessel concept which separates the functions for sustaining the differential pressure load and for sealing the vacuum system is described. The thickness of the blanket has been decreased to reduce the power density and the actinide inventory. Determination and presentation of actinide depletion characteristics represents a major element thus far in the study and is a principal objective. Evaluation of the changes in the hazard only during irradiation proved to be an inadequate measure of the reduction in long term hazards due to the importance of radioactive daughter products which appear much later in time. Therefore, comparisons have been made of long term decay characteristics before and after irradiation in the actinide burner. It has also been noted that some of the actinides that are produced during irradiation have beneficial applications as radioisotopic power sources. These and other considerations suggest that alternate approaches to assessing the waste management problem be considered to develop a meaningful perspective on long term hazards from the actinides.

  7. Octupole Deformed Nuclei in the Actinide Region

    Thorsteinsen, T; Rubio barroso, B; Simpson, J; Gulda, K; Sanchez-vega, M; Cocks, J; Nybo, K; Garcia borge, M; Aas, A; Fogelberg, B; Honsi, J; Smith, G; Naumann, R; Grant, I

    2002-01-01

    The aim of the present study is to investigate the limits of the "island" of octupole deformation in the mass region A=225. It is of particular importance to demonstrate experimentally the sudden disappearance of the stable octupole deformation in the presence of a well developed quadrupole field. \\\\ \\\\In order to establish the upper border line the $\\beta$ -decay chains of $^{227}$Rn $\\rightarrow ^{227}$Fr $\\rightarrow ^{227}$Ra and $^{231}$Fr $\\rightarrow ^{231}$Ra $\\rightarrow ^{231}$Ac were studied at PSB-ISOLDE using advanced fast timing and $\\gamma$-ray spectroscopy techniques. The lifetimes of the excited states have been measured in the picosecond range using the time-delayed $\\beta\\gamma\\gamma$(t) method.

  8. Photofission of actinide and pre-actinide nuclei in the quasideuteron and delta energy regions

    Berman, B L; Cole, P L; Dodge, W R; Feldman, G; Sanabria, J C; Kolb, N; Pywell, R E; Vogt, J; Nedorezov, V; Sudov, A; Kezerashvili, G Ya

    1999-01-01

    The photofission cross sections for the actinide nuclei sup 2 sup 3 sup 2 Th, sup 2 sup 3 sup 3 sup , sup 2 sup 3 sup 5 sup , sup 2 sup 3 sup 8 U, and sup 2 sup 3 sup 7 Np have been measured from 68 to 264 MeV and those for the pre-actinide nuclei sup 1 sup 9 sup 7 Au and sup N sup A sup T Pb from 122 to 222 MeV at the Saskatchewan Accelerator Laboratory, using monoenergetic tagged photons and novel parallel-plate avalanche detectors for the fission fragments. The aim of the experiment was to obtain a comprehensive and self-consistent data set and to investigate previous anomalous results in this energy region. The fission probability for transuranic nuclei is expected to be close to unity here. However, important discrepancies have been confirmed for sup 2 sup 3 sup 7 Np and sup 2 sup 3 sup 2 Th, compared with sup 2 sup 3 sup 8 U, which have serious implications for the inferred total photoabsorption strengths, and hence call into question the 'Universal Curve' for photon absorption at these energies. High-s...

  9. Non-compound nucleus fission in actinide and pre-actinide regions

    R Tripathi; S Sodaye; K Sudarshan

    2015-08-01

    In this article, some of our recent results on fission fragment/product angular distributions are discussed in the context of non-compound nucleus fission. Measurement of fission fragment angular distribution in 28Si+176Yb reaction did not show a large contribution from the non-compound nucleus fission. Data on the evaporation residue cross-sections, in addition to those on mass and angular distributions, are necessary for better understanding of the contribution from non-compound nucleus fission in the pre-actinide region. Measurement of mass-resolved angular distribution of fission products in 20Ne+232Th reaction showed an increase in angular anisotropy with decreasing asymmetry of mass division. This observation can be explained based on the contribution from pre-equilibrium fission. Results of these studies showed that the mass dependence of anisotropy may possibly be used to distinguish pre-equilibrium fission and quasifission.

  10. Multi-nucleon transfer experiments in the actinide region

    Geibel, Kerstin; Reiter, Peter; Birkenbach, Benedikt [Institut fuer Kernphysik, Universitaet zu Koeln (Germany); Valiente-Dobon, Jose Javier; Recchia, Francesco [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro (Italy); Gadea, Andres [IFIC, CSIC-Universidad de Valencia (Spain); Lenzi, Silvia [Dipartimento di Fisica, University of Padova (Italy)

    2012-07-01

    Two experiments at the PRISMA-CLARA-Setup at the LNL in Legnaro were analysed focussing on the target-like reaction products in the actinide region after multi-nucleon transfer reactions. Both experiments use {sup 238}U as target; a {sup 70}Zn-beam with 460 MeV and a {sup 136}Xe-beam with 926 MeV were employed. Kinematic correlations between the reaction partners are used to obtain information about the unobserved target-like reaction products by the analysis of the beam-like particles identified with the PRISMA-spectrometer. Clean {gamma}-spectra from neutron-rich actinide nuclei are obtained with the CLARA-array. An extension of the ground state rotational band in {sup 240}U and insights in neutron-rich Th-isotopes were achieved. Based on relative cross section distributions for various reaction channels the perspectives and limitations for in-beam {gamma}-spectroscopy with this experimental method in this mass region are discussed.

  11. Chemistry of gaseous lower-valent actinide halides. Technical progress report

    Objective is to provide thermochemical data for key actinide halide and oxyhalide systems. Progress is reported on bond dissociation energies of gaseous ThCl4, ThCl3, ThCl2, and ThCl; bond dissociation energies of ruthenium fluorides; and mass spectroscopy of UF6

  12. Research progress on supercritical fluid chelating extraction of lanthanides and actinides

    Supercritical fluid chelating extraction (SFCE) is a new type of separation technology for extracting metallic elements. When SFCE is used in both the spent fuel reprocessing and the treatment of nuclear wastes, the generation of second wastes can be minimized. Both the properties of supercritical fluid and the theory of SFCE were introduced, and factors affecting SFCE were discussed in the paper. The research progress on SFCE of lanthanides and actinides and applications in the process study of spent fuel reprocessing were reviewed too. (authors)

  13. Review of the fission decay of the giant resonances in the actinide region

    The fission decay of giant resonances in the actinide region is reviewed. Results from various experiments which are invariably conflicting are discussed. These include inclusive electron and positron-induced fission, as well as experiments in which fission fragments were detected in coincidence with inelastically scattered electrons or hadrons. Attention is focussed on a recent (α,α'f) experiment in which the fission decay of the giant monopole inelastically scattered α-particles at and around 00. 49 references

  14. Transmutations of nuclear waste. Progress report RAS programme 1995: Recycling and transmutation of actinides and fission products

    This report describes the progress of the Dutch RAS programme on 'Recycling and Transmutation of Actinides and Fission Products' over the year 1995, which is the second year of the 4-year programme 1994-1997. An extensive listing of reports and publications from 1991 to 1995 is given. Highlights in 1995 were: -The completion of the European Strategy Study on Nuclear Waste Transmutation as a result of which the understanding of transmutation of plutonium, minor actinides and long-lived fission products in thermal and fast reactors has been increased significantly. Important ECN contributions were given on Am, 99Tc and 129I transmutation options. Follow-up contracts have been obtained for the study of 100% MOX cores and accelerator-based transmutation. - Important progress in the evaluation of CANDU reactors for burning very large amounts of transuranium mixtures in inert matrices. - The first RAS irradiation experiment in the HFR, in which the transmutation of technetium and iodine was examined, has been completed and post-irradiation examination has been started. - A joint proposal of the EFTTRA cooperation for the 4th Framework Programme of the EU, to demonstrate the feasibility of the transmutation of americium in an inert matrix by an irradiation in the HFR, has been granted. - A bilateral contract with CEA has been signed to participate in the CAPRA programme, and the work in this field has been started. - The thesis work on Actinide Transmutation in Nuclear Reactor Systems was succesfully defended. New PhD studies on Pu burning in HTGR, on nuclear data for accelerator-based systems, and on the SLM-technique for separation of actinides were started. - A review study of the use of the thorium cycle as a means for nuclear waste reduction, has been completed. A follow-up of this work is embedded in an international project for the 4th Framework Programme of the EU. (orig./DG)

  15. Yields of neutron-rich nuclei by actinide photofission in giant dipole resonance region

    Bhowmick, Debasis; Basu, D N; Chakrabarti, Alok

    2015-01-01

    Photofission of actinides is studied in the region of nuclear excitation energies that covers the entire giant dipole resonance (GDR) region. A comparative analysis of the behavior of the symmetric and asymmetric modes of photon induced fission as a function of the average excitation energy of the fissioning nucleus is performed. The mass distributions of $^{238}$U photofission fragments are obtained at the endpoint bremsstrahlung energy of 29.1 MeV which corresponds to mean photon energy of 13.7$\\pm$0.3 MeV that coincides with GDR peak for $^{238}$U photofission. The integrated yield of $^{238}$U photofission as well as charge distribution of photofission products are calculated and its role in the production of neutron-rich nuclei and their exoticity is explored.

  16. Research in actinide chemistry. Progress report, March 1, 1980-February 28, 1981

    The primary purpose of this research is to study the behavior of actinide cations in aqueous solution. The interaction of trivalent actinides with a wide variety of both inorganic and organic ligands has been investigated with emphasis on the thermodynamics and kinetics of complexation at tracer concentrations using radiochemical techniques. In order to expand the scope of the experimental techniques, thereby obtaining additional understanding of the fundamental processes involved, non-radioactive experiments with the trivalent lanthanides have been conducted. Visible spectroscopy, nmr (11H, 613C, 57139La) spectroscopy, potentiometry, solvent extraction and calorimetry are examples of techniques for these lanthanide studies which have allowed much more thorough interpretation of the actinide tracer data due to the close chemical similarity of the lanthanide and actinide families of trivalent cations. The following were investigated: nmr shifts of 139La for both halate and chloroacetate complexes; interaction of Pu(VI) with carbonates and bicarbonates; Ca+2, UO2+2, and Th+4 reactions with halate and chloroacetate anions; complexation of the lanthanides by benzoic acid; thermodynamic formation constants for trivalent lanthanide ions with succinic, glutaric, and adipic acids; complexation of benzene polycarboxylates with lanthanides; complexation of lanthanide ions by AMP (adenosine monophosphate), ADP (adenosine diphosphate) and ATP (adenosine triphosphate); interaction of the actinides ions with humic acid; measurements of water and benzoic acid concentrations in several organic solvents by potentiometric and spectral methods; and plutonium and neptunium redox behavior in the presence of organic complexing agents

  17. Research in actinide chemistry. Progress report, March 1, 1980-February 28, 1981

    Visible spectroscopy, NMR (1H1, 6C13, 57La139) spectroscopy, potentiometry, and calorimetry were used in lanthanide studies which have allowed much more thorough interpretation of actinide tracer studies. In the last several years, the studies were expanded to include actinides in the IV, V and VI oxidation states. Part of the research during this time was directed to investigation of actinide interaction with naturally occurring polyelectrolytes such as humic and fulvic acids. Since redox reactions seemingly occur in some of these interactions, a study of plutonium and neptunium redox behavior in the presence of organic complexing agents was started. Preliminary data are given for reduction of Np(VI) by various organic acids

  18. Final Technical Progress Report Long term risk from actinides in the environment: Modes of mobility

    Thomas B. Kirchner

    2002-03-22

    The key source of uncertainty in assessing actinide mobility is the relative importance of transport by: (1) wind erosion, (2) water erosion, and (3) vertical migration. Each of these three processes depends on several environmental factors and they compete with one another. A scientific assessment of the long-term risks associated with actinides in surface soils depends on better quantifying each of these three modes of mobility. The objective from our EMSP study was to quantify the mobility of soil actinides by wind erosion, water erosion, and vertical migration at three semiarid sites where actinide mobility is a key technical, social and legal issue. This EMSP project was the first to evaluate all three factors at a site. The approach has been to investigate both short- and long-term issues based on field and lab studies and model comparisons. Our results demonstrate the importance of incorporating threshold responses into a modeling framework that accounts for environmental factors and natural disturbances that trigger large changes in actinide mobility. The study measured erosional losses of sediment and fallout cesium (an actinide analogue) from field plots located near WIPP in 1998. The results highlight the large effect of burning as a disturbance on contaminant transport and mobility via runoff and erosion. The results show that runoff, erosion, and actinide transport are (1) strongly site specific-differences in radionuclide transport between WIPP and Rocky Flats differed by a factor of twelve because of soil and vegetation differences, and (2) are strongly impacted by disturbances such as fire, which can increase runoff, erosion, and actinide transport by more than an order of magnitude. In addition, a laboratory experiment using soil columns was conducted to investigate the vertical transport of contaminants in sandy soils. Nine columns of soil collected from the vicinity of the WIPP site were prepared. The column consisted of a piece of PVC pipe 20 cm

  19. Final Technical Progress Report Long term risk from actinides in the environment: Modes of mobility; FINAL

    The key source of uncertainty in assessing actinide mobility is the relative importance of transport by: (1) wind erosion, (2) water erosion, and (3) vertical migration. Each of these three processes depends on several environmental factors and they compete with one another. A scientific assessment of the long-term risks associated with actinides in surface soils depends on better quantifying each of these three modes of mobility. The objective from our EMSP study was to quantify the mobility of soil actinides by wind erosion, water erosion, and vertical migration at three semiarid sites where actinide mobility is a key technical, social and legal issue. This EMSP project was the first to evaluate all three factors at a site. The approach has been to investigate both short- and long-term issues based on field and lab studies and model comparisons. Our results demonstrate the importance of incorporating threshold responses into a modeling framework that accounts for environmental factors and natural disturbances that trigger large changes in actinide mobility. The study measured erosional losses of sediment and fallout cesium (an actinide analogue) from field plots located near WIPP in 1998. The results highlight the large effect of burning as a disturbance on contaminant transport and mobility via runoff and erosion. The results show that runoff, erosion, and actinide transport are (1) strongly site specific-differences in radionuclide transport between WIPP and Rocky Flats differed by a factor of twelve because of soil and vegetation differences, and (2) are strongly impacted by disturbances such as fire, which can increase runoff, erosion, and actinide transport by more than an order of magnitude. In addition, a laboratory experiment using soil columns was conducted to investigate the vertical transport of contaminants in sandy soils. Nine columns of soil collected from the vicinity of the WIPP site were prepared. The column consisted of a piece of PVC pipe 20 cm

  20. Final Technical Progress Report Long term risk from actinides in the environment: Modes of mobility

    The key source of uncertainty in assessing actinide mobility is the relative importance of transport by: (1) wind erosion, (2) water erosion, and (3) vertical migration. Each of these three processes depends on several environmental factors and they compete with one another. A scientific assessment of the long-term risks associated with actinides in surface soils depends on better quantifying each of these three modes of mobility. The objective from our EMSP study was to quantify the mobility of soil actinides by wind erosion, water erosion, and vertical migration at three semiarid sites where actinide mobility is a key technical, social and legal issue. This EMSP project was the first to evaluate all three factors at a site. The approach has been to investigate both short- and long-term issues based on field and lab studies and model comparisons. Our results demonstrate the importance of incorporating threshold responses into a modeling framework that accounts for environmental factors and natural disturbances that trigger large changes in actinide mobility. The study measured erosional losses of sediment and fallout cesium (an actinide analogue) from field plots located near WIPP in 1998. The results highlight the large effect of burning as a disturbance on contaminant transport and mobility via runoff and erosion. The results show that runoff, erosion, and actinide transport are (1) strongly site specific-differences in radionuclide transport between WIPP and Rocky Flats differed by a factor of twelve because of soil and vegetation differences, and (2) are strongly impacted by disturbances such as fire, which can increase runoff, erosion, and actinide transport by more than an order of magnitude. In addition, a laboratory experiment using soil columns was conducted to investigate the vertical transport of contaminants in sandy soils. Nine columns of soil collected from the vicinity of the WIPP site were prepared. The column consisted of a piece of PVC pipe 20 cm

  1. Fundamental thermodynamics of actinide-bearing mineral waste forms. 1998 annual progress report

    'The end of the Cold War raised the need for the technical community to be concerned with the disposition of excess nuclear weapon material. The plutonium will either be converted into mixed-oxide fuel for use in nuclear reactors or immobilized in glass or ceramic waste forms and placed in a repository. The stability and behavior of plutonium in the ceramic materials as well as the phase behavior and stability of the ceramic material in the environment is not well established. In order to provide technically sound solutions to these issues, thermodynamic data are essential in developing an understanding of the chemistry and phase equilibria of the actinide-bearing mineral waste form materials proposed as immobilization matrices. Mineral materials of interest include zircon, zirconolite, and pyrochlore. High temperature solution calorimetry is one of the most powerful techniques, sometimes the only technique, for providing the fundamental thermodynamic data needed to establish optimum material fabrication parameters, and more importantly, understand and predict the behavior of the mineral materials in the environment. The purpose of this project is to experimentally determine the enthalpy of formation of actinide orthosilicates, the enthalpy of formation of actinide substituted zircon, zirconolite and pyrochlore, and develop an understanding of the bonding characteristics and stability of these materials. This report summarizes work after eight months of a three year project.'

  2. Progress towards understanding the interactions between hydroxamic acids and actinide ions

    BNFL has undertaken a wide-ranging research programme to investigate the fundamental properties of hydroxamic acids and, in particular, their reactions with actinide ions. Most work has focussed on simple hydroxamic acids (R=H and CH3) although some comparative data with more complex molecules including di-hydroxamates have been obtained. Properties of hydroxamic acids studied to date include, hydrolysis in nitric acid, decomposition to gases, pKa's and redox potentials. The redox and co-ordination chemistry of actinides by hydroxamic acids has been investigated using a range of techniques and stability constants for both 4f and 5f hydroxamate complexes have been determined. In conjunction with these fundamental studies, more applied work has been carried out to assess the applications of simple hydroxamic acids under process conditions. A large database of solvent extraction distribution data has been accumulated and, from this, extraction logarithms describing how hydroxamic acid modify actinide extraction in to TBP have been derived. Also the effects of hydroxamic acids on U and Np mass transfer have been studied in single stage centrifugal contactors and this has been modeled theoretically. The third stage of our development work so far has looked at the actual design and testing of novel hydroxamic acid based flowsheets which selectively strip Np(IV) and Py(IV) from a uranium loaded TBP stream. (author)

  3. Towards Synthesis and Usage of Actinide-Bearing REE Phosphate age Standards: A Progress Report

    Pyle, J. M.; Cherniak, D. J.

    2006-05-01

    Electron microprobe (EMP) dates result from a concentration-time unit conversion, so use of a concentration- based (rather than isotope-ratio based) fictive age standard is warranted. This observation has motivated our mineral synthesis program, aimed at producing actinide-doped REE phosphate EMP dating standards that meet the following criteria: 1) known concentrations of U, Th, and Pb; 2) homogeneous intragrain distribution of all components; 3) of suitable size, either as a single-crystal or polycrystalline sintered ceramic. Single-crystal synthesis of actinide-doped LaPO4 by flux-growth methods results in disproportionation of lanthanide and flux, alkali, and actinide components into phosphate and oxide phases, respectively, and flux- growth methods were abandoned. Actinide-doped La phosphate is successfully prepared by high-T annealing and hydrothermal processing of microcrystalline phosphate; both homogeneity and charge-balance of (Ca, Th, Pb)-bearing LaPO4 increase with increasing solvent acidity during cold-seal hydrothermal synthesis. A combination of pressing and high-T (1400° C) sintering transforms fine-grained (0.1-10 μm) run- products to ceramic pellets with 90-95% theoretical density. Our most recent runs focused on a target composition of La80(CaTh)17(CaU)2(PbTh)1PO4 processed with 6% 2M HCl at 820° C, 0.75 kbar for 1 week. The run products are 0.1-2 μm crystals identified by XRD as La-actinide phosphate solid solution. 2 μm grains (N=16) give a composition (mean±2 sd) of La79.77(1.26)(CaTh)17.87(1.00)(CaU)1.53(0.42)(PbTh)0.82(0.09)PO4. Th (8.07-9.13 wt. %) is homogeneous at the level of analytical precision, and the Pb concentration range (3500-4350 ppm) is restricted relative to untreated precipitate. Uranium concentration values are more variable (6500-10000 ppm). This run yields a fictive age of 702±4 Ma (mean±2 se), compared to the fictive age of 794 Ma for the target composition.

  4. Chemical and ceramic methods for the safe storage of actinides using monazite. 1997 annual progress report

    'Oak Ridge National Laboratory (ORNL) and the Rockwell Science Center of Thousand Oaks, California, are carrying out a joint investigation of the chemical, physical, thermal, and radiation-resistance properties of the lanthanide orthophosphates (monazites) in both ceramic and single-crystal form with the objective of developing the scientific and technical base required for the application of these materials to the storage or disposal of actinide elements, including plutonium. An additional major objective of the research effort is to investigate the technical and scientific problems associated with the formation of both phase-pure monazite ceramics and multiphase monazite-ceramic composites for waste disposal or waste storage applications. These latter investigations encompass the development of low-temperature chemical synthesis routes for the formation of monoclinic monazite phases and the study of the densification properties of lanthanide orthophosphate powders to produce stable, high-density ceramics. Research Statement This research effort addresses several basic issues associated with the characteristics of lanthanide orthophosphates that make this class of materials extremely attractive candidates for application to the storage of actinide elements in general and plutonium in particular. Additionally, these materials are potentially important refractory ceramics in their own right, and many of the scientific issues addressed in this project are applicable to the development of what will constitute a new, highly stable family of ceramics for applications in a number of energy-related areas.'

  5. Actinide environmental chemistry

    In order to predict release and transport rates, as well as design cleanup and containment methods, it is essential to understand the chemical reactions and forms of the actinides under aqueous environmental conditions. Four important processes that can occur with the actinide cations are: precipitation, complexation, sorption and colloid formation. Precipitation of a solid phase will limit the amount of actinide in solution near the solid phase and have a retarding effect on release and transport rates. Complexation increases the amount of actinide in solution and tends to increase release and migration rates. Actinides can sorb on to mineral or rock surfaces which tends to retard migration. Actinide ions can form or become associated with colloidal sized particles which can, depending on the nature of the colloid and the solution conditions, enhance or retard migration of the actinide. The degree to which these four processes progress is strongly dependent on the oxidation state of the actinide and tends to be similar for actinides in the same oxidation state. In order to obtain information on the speciation of actinides in solution, i.e., oxidation state, complexation form, dissolved or colloidal forms, the use of absorption spectroscopy has become a method of choice. The advent of the ultrasensitive, laser induced photothermal and fluorescence spectroscopies has made possible the detection and study of actinide ions at the parts per billion level. With the availability of third generation synchrotrons and the development of new fluorescence detectors, X-ray absorption spectroscopy (XAS) is becoming a powerful technique to study the speciation of actinides in the environment, particularly for reactions at the solid/solution interfaces. (orig.)

  6. Level Densities in the actinide region and indirect n,y cross section measurements using the surrogate method

    Wiedeking M.

    2012-02-01

    Full Text Available Results from a program of measurements of level densities and gamma ray strength functions in the actinide region are presented. Experiments at the Oslo cyclotron involving the Cactus/Siri detectors and 232Th(d,x and 232Th(3He,x reactions were carried out to help answer the question of which level density model is the most appropriate for actinide nuclei, since it will have an impact on cross section calculations important for reactor physics simulations. A new technique for extracting level densities and gamma ray strength functions from particle-gamma coincidence data is proposed and results from the development of this technique are presented. In addition, simultaneous measurements of compound nuclear gamma decay probabilities have been performed for the key thorium cycle nuclei 233Th, 231Th and 232Pa up to around 1MeV above the neutron binding energy and have enabled extraction of indirect neutron induced capture cross sections for the 232Th, 231Pa and 230Th nuclei using the surrogate reaction method. Since the neutron capture cross section for 232Th is already well known from direct measurements a comparison provides a stringent test of the applicability of the surrogate technique in the actinide region.

  7. Level Densities in the actinide region and indirect n,y cross section measurements using the surrogate method

    Wilson, J. N.; Gunsing, F.; Bernstein, L.; Bürger, A.; Görgen, A.; Thompson, I. J.; Guttormssen, M.; Larsen, A.-C.; Mansouri, P.; Renstrøm, T.; Rose, S. J.; Siem, S.; Wiedeking, M.; Wiborg, T.

    2012-02-01

    Results from a program of measurements of level densities and gamma ray strength functions in the actinide region are presented. Experiments at the Oslo cyclotron involving the Cactus/Siri detectors and 232Th(d,x) and 232Th(3He,x) reactions were carried out to help answer the question of which level density model is the most appropriate for actinide nuclei, since it will have an impact on cross section calculations important for reactor physics simulations. A new technique for extracting level densities and gamma ray strength functions from particle-gamma coincidence data is proposed and results from the development of this technique are presented. In addition, simultaneous measurements of compound nuclear gamma decay probabilities have been performed for the key thorium cycle nuclei 233Th, 231Th and 232Pa up to around 1MeV above the neutron binding energy and have enabled extraction of indirect neutron induced capture cross sections for the 232Th, 231Pa and 230Th nuclei using the surrogate reaction method. Since the neutron capture cross section for 232Th is already well known from direct measurements a comparison provides a stringent test of the applicability of the surrogate technique in the actinide region.

  8. Effects of humic substances on the migration of radionuclides: Complexation of actinides with humic substances. 1. progress report

    The aim of the present research programme is to study the complexation behaviour of actinide ions with humic substances in natural aquifer systems and hence to quantify the effect of humic substances on the actinide migration. Aquatic humic substances commonly found in all groundwaters in different concentrations have a strong tendency towards complexation with actinide ions. This is one of the major geochemical reactions but hitherto least quantified. Therefore, the effect of humic substances on the actinide migration is poorly understood. In the present research programme the complexation of actinide ions with humic substances will be described thermodynamically. This description will be based on a model being as simple as possible to allow an easy introduction of the resulting constants into geochemical modelling of the actinide migration. This programme is a continuation of the activities of the COCO group in the second phase of the CEC-MIRAGE project. (orig.)

  9. Chemical and ceramic methods toward safe storage of actinides using monazite. 1998 annual progress report

    'The use of ceramic monazite, (La,Ce)PO4, for sequestering actinides, especially plutonium, and some other radioactive waste elements (rare earths e.g.) and thus isolating them from the environment has been championed by Lynn Boatner of ORNL. It may be used alone or, as it is compatible with many other minerals in nature, can be used in composite combinations. Natural monazite, which almost invariably contains Th and U, is often formed in hydrothermal pegmatites and is extremely water resistant--examples are known where the mineral has been washed out of rocks (becoming a placer mineral as on the beach sands of India, Australia, Brazil etc.) then reincorporated into new rocks with new crystal overgrowths and then washed out again--being 2.5--3 billion years old. During this demanding water treatment it has retained Th and U. Where very low levels of water attack have been seen (in more siliceous waters), the Th is tied up as new ThSiO4 and remains immobile. Lest it be thought that rare-earths are rare or expensive, this is not so. In fact, the less common lanthanides such as gadolinium, samarium, europium, and terbium, are necessarily extracted and much used by, e.g., the electronics industry, leaving La and Ce as not-sufficiently-used by-products. The recent development of large scale use of Nd in Nd-B-Fe magnets has further exaggerated this. Large deposits of the parent mineral bastnaesite are present in the USA and in China. (Mineral monazite itself is not preferred due to its thorium content.) In the last 5 years it has become apparent show that monazite (more specifically La-monazite) is an unrecognized/becoming-interesting ceramic material. PuPO4 itself has the monazite structure; the PO4 3-unit strongly stabilizes actinides and rare earths in their trivalent state. Monazite melts without decomposition (in a closed system) at 2,074 C and, being compatible with common ceramic oxides such as alumina, mullite, zirconia and YAG, is useful in oxidatively stable

  10. Biosorption of technetium-99 and some actinides by bottoms borrowed from Beloe lake of Kosino of Moscow region

    Sorption of technetium, plutonium and curium by sterile and natural silts taken from the Beloe lake in Kosino, Moscow region, has been studied. It is shown that in 4.5 months technetium sorption by natural silts has reached 98%. The mechanism of technetium sorption involves sulfide formation, which transfers the original soluble pertechnetate-ion into insoluble technetium (7) and (4) sulfides. Sorption of the actinides by natural silts amounts to 98%, the one by sterile silts-46%. The solid/liquid phase ratio is 2.3·10-2 g/ml. 14 refs., 2 figs., 2 tabs

  11. Regional Cerebral Perfusion in Progressive Supranuclear Palsy

    Lee, Won Yong; Lee, Ki Hyeong; Yoon, Byung Woo; Lee, Sang Bok; Jeon, Beom S. [Samsung Medical Center, Seoul (Korea, Republic of); Lee, Kyung Han; Lee, Myung Chul [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1996-03-15

    Progressive supranuclear palsy (PSP) is a Parkinson-plus syndrome characterized clinically by supranuclear ophthalmoplegia, pseudobulbar palsy, axial rigidity, bradykinesia, postural instability and dementia. Presence of dementia and lack of cortical histopathology suggest the derangement of cortical function by pathological changes in subcortical structures in PSP, which is supported by the pattern of behavioral changes and measurement of brain metabolism using positron emission tomography. This study was done to examine whether there are specific changes of regional cerebral perfusion in PSP and whether there is a correlation between severity of motor abnormaility and degree of changes in cerebral perfusion. We measured regional cerebral perfusion indices in 5 cortical and 2 subcortical areas in 6 patients with a clinical diagnosis of PSP and 6 healthy age and sex matched controls using Tc-99m-HMPAO SPECT. Compared with age and sex matched controls, only superior frontal regional perfusion index was significantly decreased in PSP (p<0.05). There was no correlation between the severity of the motor abnormality and any of the regional cerebral perfusion indices (p>0.05). We affirm the previous reports that perfusion in superior frontal cortex is decreased in PSP. Based on our results that there was no correlation between severity of motor abnormality and cerebral perfusion in the superior frontal cortex, nonmotoric symptoms including dementia needs to be looked at whether there is a correlation with the perfusion abnormality in superior frontal cortex

  12. Actinides-1981

    1981-09-01

    Abstracts of 134 papers which were presented at the Actinides-1981 conference are presented. Approximately half of these papers deal with electronic structure of the actinides. Others deal with solid state chemistry, nuclear physic, thermodynamic properties, solution chemistry, and applied chemistry.

  13. Actinides-1981

    Abstracts of 134 papers which were presented at the Actinides-1981 conference are presented. Approximately half of these papers deal with electronic structure of the actinides. Others deal with solid state chemistry, nuclear physic, thermodynamic properties, solution chemistry, and applied chemistry

  14. Regional Cerebral Perfusion in Progressive Supranuclear Palsy

    Progressive supranuclear palsy (PSP) is a Parkinson-plus syndrome characterized clinically by supranuclear ophthalmoplegia, pseudobulbar palsy, axial rigidity, bradykinesia, postural instability and dementia. Presence of dementia and lack of cortical histopathology suggest the derangement of cortical function by pathological changes in subcortical structures in PSP, which is supported by the pattern of behavioral changes and measurement of brain metabolism using positron emission tomography. This study was done to examine whether there are specific changes of regional cerebral perfusion in PSP and whether there is a correlation between severity of motor abnormaility and degree of changes in cerebral perfusion. We measured regional cerebral perfusion indices in 5 cortical and 2 subcortical areas in 6 patients with a clinical diagnosis of PSP and 6 healthy age and sex matched controls using Tc-99m-HMPAO SPECT. Compared with age and sex matched controls, only superior frontal regional perfusion index was significantly decreased in PSP (p0.05). We affirm the previous reports that perfusion in superior frontal cortex is decreased in PSP. Based on our results that there was no correlation between severity of motor abnormality and cerebral perfusion in the superior frontal cortex, nonmotoric symptoms including dementia needs to be looked at whether there is a correlation with the perfusion abnormality in superior frontal cortex

  15. Comparison of experimental and theoretical binding and transition energies in the actinide region

    The present status of experimental and theoretical binding and transition energy determinations is reviewed. Experimental data and the most recent theoretical predictions are compared for the energies of Kα1 X-rays, M series X-rays, K-LL Auger electrons, K, L3, M and N levels, and the 4f spin-orbit splitting. In addition, the Kα1 and L3 data are fitted by Moseley-type diagrams, and data on the shallow levels and the valence bands of actinide oxides are discussed. Comparison shows that the single-particle Dirac-Fock theory and the inclusion of quantum-electrodynamic contributions predicts energies of the innermost levels generally within the accuracy of data, that is in the order of magnitude of 1 eV. However, in the N, O... shells large deviations do occur presumably due to strong many-electron interactions. The inclusion of many-electron effects in the relativistic theory remains a challenge, as do experimental investigations affording an accuracy of better than 1 eV for the various electronic levels. (Auth.)

  16. Thermodynamics of the volatilization of actinide metals in the high-temperature treatment of radioactive wastes. 1998 annual progress report

    'In this project, the authors perform a detailed study of the volatilization behavior of U, Pu and possibly Am and Np under conditions relevant to the thermal treatment (destruction) of actinide-containing organic-based mixed and radioactive wastes. The primary scientific goal of the proposed work is to develop a basic thermochemical understanding of actinide volatilization and partitioning/speciation behavior in the thermal processes that are central to DOE/EM''s mixed waste treatment program. This subject addresses several technical needs/problem areas recently identified by DOE/EM''s Office of Science and Technology. In the Low-Level and Mixed Low-Level Waste problem area, emission-free destruction of organic wastes is listed as the first exemplary science need. In the TRU Waste, Plutonium Materials, and Spent Nuclear Fuel problem areas, interactions between actinides and organic residues and materials stabilization are listed as exemplary science needs. Both of these needs require high-temperature thermodynamic studies of actinides and actinide-organic interactions. A sound basis for designing safe and effective thermal treatment systems and the ability to allay public concerns about radioactive fugitive emissions are the principal benefits of the project. The proposed work is a combination of experimental studies and thermodynamic modeling. Vapor pressure measurements will be made to determine U, Pu and possibly Am volatile species and the extent of their volatilization when UO2/U3O8, PuO2 and AmO2 solids are heated to temperatures of 500 to 1,500 C under pyrolyzing (reducing) conditions or under oxidizing conditions (i.e. O2 (g) + H2O(g) mixtures) in the presence of chlorine (Cl2 (g) or HCl(g)). Work on uranium volatilization under reducing conditions will be performed in a laboratory at U. C. Berkeley in a collaboration with Professor D. R. Olander. In parallel with the experimental effort, a complete thermodynamic database for expected actinide gaseous

  17. Search for proton emission in {sup 54}Ni and multi-nucleon transfer reactions in the actinide region

    Geibel, Kerstin

    2012-06-15

    products by the analysis of the beam-like particles identified with the PRISMA spectrometer. γ spectra from neutron-rich actinide nuclei are obtained with the CLARA array. An extension of the ground-state rotational band in {sup 240}U up to the 18{sup +} state is achieved. The level and transition energies as well as the moments of inertia are compared with theoretical predictions. Based on cross section distributions for various reaction channels the perspectives and limitations for in-beam γ spectroscopy with this experimental method in the actinide region are discussed.

  18. Application of the EXtrapolated Efficiency Method (EXEM) to infer the gamma-cascade detection efficiency in the actinide region

    Ducasse, Q; Mathieu, L; Marini, P; Morillon, B; Aiche, M; Tsekhanovich, I

    2015-01-01

    The study of transfer-induced gamma-decay probabilities is very useful for understanding the surrogate-reaction method and, more generally, for constraining statistical-model calculations. One of the main difficulties in the measurement of gamma-decay probabilities is the determination of the gamma-cascade detection efficiency. In [Nucl. Instrum. Meth. A 700, 59 (2013)] we developed the Extrapolated Efficiency Method (EXEM), a new method to measure this quantity. In this work, we have applied, for the first time, the EXEM to infer the gamma-cascade detection efficiency in the actinide region. In particular, we have considered the 238U(d,p)239U and 238U(3He,d)239Np reactions. We have performed Hauser-Feshbach calculations to interpret our results and to verify the hypothesis on which the EXEM is based. The determination of fission and gamma-decay probabilities of 239Np below the neutron separation energy allowed us to validate the EXEM.

  19. Humic substances in performance assessment of nuclear waste disposal: Actinide and iodine migration in the far-field. Third technical progress report

    The present report describes progress within the third and final year of the EC-project 'Humic Substances in Performance Assessment of Nuclear Waste Disposal: Actinide and Iodine Migration in the Far-Field'. The work conducted within the present project builds on a number of previous activities/project supported by the Commission. It finds its continuation within different EC FP 6 instruments and also provides for additional continued cooperation through network structures resulting from the broad cooperation within the project. Without being a formal requirement of the Commission or co-funding bodies, this report documents results in great technical detail and makes the results available to a broad scientific community. The report contains an executive summary written by the coordinator. More detailed results are given as individual contributions in the form of 12 annexes. Not all results are discussed or referred to in the executive summary report and thus readers with a deeper interest also need to consult the annexes. The overall objectives were to generate knowledge about the impact of humic substances on the migration of actinides and iodine in the far-field of a nuclear waste repository. In the beginning, focus was rather on the potential enhancement due to humic colloid mediated radionuclide transport. Thereby, sources, inventory, stability and mobility of dissolved humic substances in their colloidal form formed a key topic. Other key topics were the interaction with actinides and iodine, transport studies under near-natural conditions in the laboratory, rationalization of knowledge in models and application to three migration cases for visualization of the overall outcome. Changes relative to the original objectives were given by moving emphasis of natural chemical analogue studies from the question of kinetic exchange constants for different inventories in natural and laboratory systems to the study of anthropogenic actinide contaminants in the Irish Sea

  20. Analyses in Support of Z-Pinch IFE and Actinide Transmutation - LLNL Progress Report for FY-06

    Meier, W R; Moir, R W; Abbott, R

    2006-09-19

    This report documents results of LLNL's work in support of two studies being conducted by Sandia National Laboratories (SNL): the development of the Z-pinch driven inertial fusion energy (Z-IFE), and the use of Z-pinch driven inertial fusion as a neutron source to destroy actinides from fission reactor spent fuel. LLNL's efforts in FY06 included: (1) Development of a systems code for Z-IFE and use of the code to examine the operating parameter space in terms of design variables such as the Z-pinch driver energy, the chamber pulse repetition rate, the number of chambers making up the power plant, and the total net electric power of the plant. This is covered in Section 3 with full documentation of the model in Appendix A. (2) Continued development of innovative concepts for the design and operation of the recyclable transmission line (RTL) and chamber for Z-IFE. The work, which builds on our FY04 and FY05 contributions, emphasizes design features that are likely to lead to a more attractive power plant including: liquid jets to protect all structures from direct exposure to neutrons, rapid insertion of the RTL to maximize the potential chamber rep-rate, and use of cast flibe for the RTL to reduce recycling and remanufacturing costs and power needs. See Section 4 and Appendix B. (3) Description of potential figures of merit (FOMs) for actinide transmutation technologies and a discussion of how these FOMs apply and can be used in the ongoing evaluation of the Z-pinch actinide burner, referred to as the In-Zinerator. See Section 5. (4) A critique of, and suggested improvements to, the In-Zinerator chamber design in response to the SNL design team's request for feedback on its preliminary design. This is covered in Section 6.

  1. Revamped half-lives of super heavy elements (SHE) in trans-actinide region

    Analyzation of alpha decay properties and identification of Island of Stability has illuminated the theories of nuclear physics. This fundamental scientific research is the current ongoing work in the field of super heavy elements. In order to study the decay properties of super heavy elements a realistic model called as Cubic plus Yukawa plus Exponential (CYE) model is used here. This model uses a cubic potential in the pre-scission region connected by Coulomb plus Yukawa plus Exponential potential in the post scission region

  2. Actinide recycle

    A multitude of studies and assessments of actinide partitioning and transmutation were carried out in the late 1970s and early 1980s. Probably the most comprehensive of these was a study coordinated by Oak Ridge National Laboratory. The conclusions of this study were that only rather weak economic and safety incentives existed for partitioning and transmuting the actinides for waste management purposes, due to the facts that (1) partitioning processes were complicated and expensive, and (2) the geologic repository was assumed to contain actinides for hundreds of thousands of years. Much has changed in the few years since then. A variety of developments now combine to warrant a renewed assessment of the actinide recycle. First of all, it has become increasingly difficult to provide to all parties the necessary assurance that the repository will contain essentially all radioactive materials until they have decayed. Assurance can almost certainly be provided to regulatory agencies by sound technical arguments, but it is difficult to convince the general public that the behavior of wastes stored in the ground can be modeled and predicted for even a few thousand years. From this point of view alone there would seem to be a clear benefit in reducing the long-term toxicity of the high-level wastes placed in the repository

  3. Neutron scattering studies in the actinide region. Progress report, July 2, 1984-July 30, 1985

    During the past year we have been engaged in the following research areas: (1) analysis of the measurements of excitation functions for 232Th neutron elastic scattering as well as inelastic scattering for the first two excited states at 49 and 162 keV from 0.9 to 2.5 MeV incident energy; (2) elastic and inelastic neutron scattering angular distribution measurements on 235U, 238U and 232Th at 550 keV; (3) neutron scattering angular distribution measurements on 235U, 238U and 232Th at 200 keV; (4) 235U (n,n'γ) measurements; (5) preparation of an iron-filter neutron time-of-flight spectrometer; (6) presentation of results of (n,n') studies on states above 680 keV in 238U in a collaborative effort with Dr. E.D. Arthur of Los Alamos National Laboratory; (7) theoretical neutron inelastic scattering cross section calculations for 232Th, 238U and 240242244Pu and (8) improvements to the accelerator operation. 25 refs., 14 figs

  4. Synthesis, chemistry, and catalytic activity of complexes of lanthanide and actinide metals in unusual oxidation states and coordination environments. Progress report, February 1, 1981-January 31, 1982

    The objectives of this research project are: (1) to demonstrate experimentally that the lanthanide and actinide metals have a more extensive chemistry than is presently known; (2) to develop a better understanding of the special features of the f orbital elements which will allow the design of f orbital complexes possessing unique chemical and physical properties; (3) to provide a basis for seeking unusual catalytic transformations involving these elements; and (4) to synthesize and explore the chemical and physical properties of mixed metal complexes which contain both lanthanide and transition metals. During the past year progress was made in each area. Some of the specific results are: (1) the first activation of CO by an organolanthanide complex was demonstrated; (2) the first, crystallograhically characterized, molecular lanthanide hydride complexes, the bridged dimers, [(C5H4R)2LnH(THF)]2 (R=H, CH3; Ln=Lu, Er, Y), were synthesized by hydrogenolysis of the appropriate (C5H4R)2Ln(C(CH3)3)(THF) complex; (3) [(C5H5)2(THF)ErH]2 was found to catalyze the homogeneous hydrogenation of alkynes; (4) the first trimetallic organolanthanide complex was synthesized; (5) the first polyhydridic organolanthanide complex was synthesized; (6) U(III) hydride was found to catalytically activate molecular hydrogen in alkene and alkyne hydrogenation reactions

  5. PROGRESS OF CHINESE REGIONAL GEOGRAPHYSTUDIES IN RECENT TWENTY YEARS

    2000-01-01

    Regional geography, embodying the regionality and integration, is the kernel of Geography. Since the 1980s, the Chinese geographers have extensively taken part in the social practical activities and made progress in physicogeographical regionalization, economic regionalization, territorial (regional) development planning, construction of special economic zone, and integrated research in the major areas of China. Through these works, the theories of regional geography have been richened and the capacity participating in the social practice promoted as well. In China, many regional researches had been conducted respectively from the aspects of regional physico-geography and regional economic geography,etc. According to the cases, this paper gives a review on the studies of regional geography during the latest two decades in China. It ought to be indicated that the natural and human components should be combined and the disciplines intersected and permeated, with the support of advanced technology. In order to serve the regional sustainable development, on the background of global change, this is an inevitable tendency for the development of the regional geography.

  6. Effects of humic substances on the migration of radionuclides: Complexation of actinides with humic substances. 4. progress report

    In this report a number of methodical developments are in progress. The effective ligand concentration is one of the important parameters for the evaluation of the metal ion complexation behaviour of bulk polyelectrolytes like humic or fulvic acids. Studies by KUL and TUM show that the effective ligand concentration of humic acid is related to the protonation of the ion exchanging groups. For a precise evaluation of the complexation reaction, however, a direct measurement of the effective ligand capacity under given experimental conditions is neccessary. The humate complexation has been studied for pentavalent neptunium (UM), hexavalent uranium (TUM) and trivalent lanthanide ions (CEA, UM and KUL) under different experimental conditions. The pH is varied between 3.0 and 9.0, the ionic strength between 0.01 and 0.1 M with metal ion concentrations between 10-13 and 10-5 mol/L. Competition of Al3+, [Co(NH3)6]3+, Ca2+, Cu2+, Fe2+ and Na+ on the Eu humate interaction is investigated by KUL. CEA-FAR has studied the influence of temperature on the Dy(III) humate complexation as well as the Dy(III) complexation with EDTA for the purpose of comparison. Studies by KUL on the influence of different competing ligands show that in such a ternary system (metal ion, humic acid and competing ligand) mixed complexes are generated. (orig.)

  7. Assessment of regional progression of pulmonary emphysema with CT densitometry

    Bakker, M Els; Putter, Hein; Stolk, Jan;

    2008-01-01

    with general emphysema (general emphysema without phenotype PiZZ [non-PiZ] group) were scanned with CT at baseline and after 30 months. Densitometry was performed in 12 axial partitions of equal volumes. To indicate predominant location, craniocaudal locality was defined as the slope in the plot of densities......BACKGROUND: Lung densitometry is an effective method to assess overall progression of emphysema, but generally the location of the progression is not estimated. We hypothesized that progression of emphysema is the result of extension from affected areas toward less affected areas in the lung....... To test this hypothesis, a method was developed to assess emphysema severity at different levels in the lungs in order to estimate regional changes. METHODS: Fifty subjects with emphysema due to alpha(1)-antitrypsin deficiency (AATD) [AATD deficiency of phenotype PiZZ (PiZ) group] and 16 subjects...

  8. Summary Report of the Technical Meeting on Inelastic Scattering and Capture Cross-section Data of Major Actinides in the Fast Neutron Region

    Recently, tight target uncertainties on the capture and inelastic scattering data for major actinides were derived from advanced reactor sensitivity studies. A Technical Meeting on 'Inelastic Scattering and Capture Cross-section Data of Major Actinides in the Fast Neutron Region' was held at IAEA Headquarters, Vienna, Austria to review the status of nuclear data libraries for these cross sections, the status of the experimental results by which these can be tested and to evaluate what advances in nuclear modeling and measurement technique may bring to improve the knowledge of these cross sections. The participants compared recent evaluations with various modeling approaches that have not yet been adopted in data libraries. Several points of interest were found. First, different evaluations may show very similar performance for macroscopic benchmarks. Second, recent modeling improvements from different communities and using different codes tend to converge on the principles in the case of coupled channel calculations. In particular, it was shown that meaningful results require convergence with respect to the number of coupled channels and the use of the dispersive coupled channels potential based with an isospin dependent term to treat neutrons and protons in a coherent manner appears to be uncontested. Also, the issue regarding the use of transmission coefficients from coupled channels calculations in the Hauser Feshbach model was tackled. Recent and ongoing experimental efforts were presented for capture and inelastic scattering on the major actinides. Results from these are likely to become available in a period from 2 to 5 years. A discussion on the representation of the data in EXFOR revealed that care must be taken interpreting the numbers given in the case of inelastic scattering. It has been a long time since capture data were obtained for fissile nuclei and it is exciting to find new efforts are being considered at LANL, CERN and CENBG/IRMM. It was finally

  9. Actinide Source Term Program, position paper. Revision 1

    The Actinide Source Term represents the quantity of actinides that could be mobilized within WIPP brines and could migrate with the brines away from the disposal room vicinity. This document presents the various proposed methods for estimating this source term, with a particular focus on defining these methods and evaluating the defensibility of the models for mobile actinide concentrations. The conclusions reached in this document are: the 92 PA open-quotes expert panelclose quotes model for mobile actinide concentrations is not defensible; and, although it is extremely conservative, the open-quotes inventory limitsclose quotes model is the only existing defensible model for the actinide source term. The model effort in progress, open-quotes chemical modeling of mobile actinide concentrationsclose quotes, supported by a laboratory effort that is also in progress, is designed to provide a reasonable description of the system and be scientifically realistic and supplant the open-quotes Inventory limitsclose quotes model

  10. Progress toward regional measles elimination - worldwide, 2000-2014.

    Perry, Robert T; Murray, Jillian S; Gacic-Dobo, Marta; Dabbagh, Alya; Mulders, Mick N; Strebel, Peter M; Okwo-Bele, Jean-Marie; Rota, Paul A; Goodson, James L

    2015-11-13

    In 2000, the United Nations General Assembly adopted the Millennium Development Goals (MDG), with MDG4 being a two-thirds reduction in child mortality by 2015, and with measles vaccination coverage being one of the three indicators of progress toward this goal.* In 2010, the World Health Assembly established three milestones for measles control by 2015: 1) increase routine coverage with the first dose of measles-containing vaccine (MCV1) for children aged 1 year to ≥90% nationally and ≥80% in every district; 2) reduce global annual measles incidence to fewer than five cases per million population; and 3) reduce global measles mortality by 95% from the 2000 estimate (1).† In 2012, the World Health Assembly endorsed the Global Vaccine Action Plan§ with the objective to eliminate measles in four World Health Organization (WHO) regions by 2015. WHO member states in all six WHO regions have adopted measles elimination goals. This report updates the 2000–2013 report (2) and describes progress toward global control and regional measles elimination during 2000–2014. During this period, annual reported measles incidence declined 73% worldwide, from 146 to 40 cases per million population, and annual estimated measles deaths declined 79%, from 546,800 to 114,900. However, progress toward the 2015 milestones and elimination goals has slowed markedly since 2010. To resume progress toward milestones and goals for measles elimination, a review of current strategies and challenges to improving program performance is needed, and countries and their partners need to raise the visibility of measles elimination, address barriers to measles vaccination, and make substantial and sustained additional investments in strengthening health systems. PMID:26562349

  11. The lanthanides and actinides

    This paper relates the chemical properties of the actinides to their position in the Mendeleev periodic system. The changes in the oxidation states of the actinides with increasing atomic number are similar to those of the 3d elements. Monovalent and divalent actinides are very similar to alkaline and alkaline earth elements; in the 3+ and 4+ oxidation states they resemble d elements in the respective oxidation states. However, in their highest oxidation states the actinides display their individual properties with only a slight resemblance to d elements. Finally, there is a profound similarity between the second half of the actinides and the first half of the lanthanides

  12. Regional odontodysplasia: A case of progressive tooth development

    R Ganguly

    2012-01-01

    Full Text Available Regional odontodysplasia (RO is considered a relatively rare dental anomaly despite increasing numbers of case reports in recent years. It usually presents as a localized anomaly in tooth development affecting a few adjacent teeth in a single maxillary or mandibular quadrant. The purpose of this paper is to describe an uncommon case of regional odotodysplasia involving noncontiguous mandibular teeth, crossing the midline in a male patient, and showing progressive normalization of tooth anatomy over a period of 6 years. Typically, teeth affected with RO become pulpally involved early on and are either extracted or endodontically treated. Such reports of automatic normalization over time in RO is supportive of a more conservative treatment approach.

  13. Actinide and fission product separation and transmutation

    NONE

    1993-07-01

    The second international information exchange meeting on actinide and fission product separation and transmutation, took place in Argonne National Laboratory in Illinois United States, on 11-13 November 1992. The proceedings are presented in four sessions: Current strategic system of actinide and fission product separation and transmutation, progress in R and D on partitioning processes wet and dry, progress in R and D on transmutation and refinements of neutronic and other data, development of the fuel cycle processes fuel types and targets. (A.L.B.)

  14. Actinide and fission product separation and transmutation

    The second international information exchange meeting on actinide and fission product separation and transmutation, took place in Argonne National Laboratory in Illinois United States, on 11-13 November 1992. The proceedings are presented in four sessions: Current strategic system of actinide and fission product separation and transmutation, progress in R and D on partitioning processes wet and dry, progress in R and D on transmutation and refinements of neutronic and other data, development of the fuel cycle processes fuel types and targets. (A.L.B.)

  15. Lattice effects in the light actinides

    The light actinides show a variety of lattice effects that do not normally appear in other regions of the periodic table. The article will cover the crystal structures of the light actinides, their atomic volumes, their thermal expansion behavior, and their elastic behavior as reflected in recent thermal vibration measurements made by neutron diffraction. A discussion of the melting points will be given in terms of the thermal vibration measurements. Pressure effects will be only briefly indicated

  16. Effects of humic substances on the migration of radionuclides: Complexation of actinides with humic substances. (6th progress report, project summary). Period covered: January 1994 - July 1994

    The goal of the research project is to examine the complexation behaviour of actinide ions with humic substances and thermodynamically describe the binding based upon a simple complexation model. This program is a continuation of the activities of the colloid and complexation group (COCO) in the second phase of the EC-MIRAGE project. A number of different experimental methods are used to determine speciation. The metal ions examined are the trivalent lanthanides, UO22+, NpO2+, Am3+, and Cm3+. The project is divided into three tasks: Task 1: complexation reactions of actinide ions with well characterized reference and site-specific humic and fulvic acids, Task 2: complexation reactions with major cations in natural groundwaters; Task 3: validation of the complexation data in natural aquatic systems by comparison of calculation with spectroscopic experiment. Five European community laboratories participated in the program: Technische Universitaet Muenchen, Commissariat a l'Energie Atomique Fontenay-Aux-Roses and Saclay, Universitaet Mainz, Katolieke Universiteit Leuven, and Joint Research Centre, Ispra. The evaluated stability constants are similar for all laboratories when the same humic substance complexation model is applied. Humic acid is shown to reduce NpO2+ to Np4+, while no reduction of UO22+ is observed. Temperature effects are seen on the Np humate complex. Competition is observed between NpO2+ and Ca2+, but not between the trivalent lanthanides and Ca2+. No influence of humic acid purification on the evaluated stability constants is seen. Using the evaluated constants, calculations are conducted for natural water systems which indicate the trivalent actinide humate complex to be an important species. (orig.)

  17. Research in actinide chemistry

    This research studies the behavior of the actinide elements in aqueous solution. The high radioactivity of the transuranium actinides limits the concentrations which can be studied and, consequently, limits the experimental techniques. However, oxidation state analogs (trivalent lanthanides, tetravalent thorium, and hexavalent uranium) do not suffer from these limitations. Behavior of actinides in the environment are a major USDOE concern, whether in connection with long-term releases from a repository, releases from stored defense wastes or accidental releases in reprocessing, etc. Principal goal of our research was expand the thermodynamic data base on complexation of actinides by natural ligands (e.g., OH-, CO32-, PO43-, humates). The research undertakes fundamental studies of actinide complexes which can increase understanding of the environmental behavior of these elements

  18. Actinide elements in aquatic and terrestrial environments

    Progress is reported on the following research projects: water-sediment interactions of U, Pu, Am, and Cm; relative availability of actinide elements from abiotic to aquatic biota; comparative uptake of transuranic elements by biota bordering Pond 3513; metabolic reduction of 239Np from Np(V) to Np(IV) in cotton rats; evaluation of hazards associated with transuranium releases to the biosphere; predicting Pu in bone; adsorption--solubility--complexation phenomena in actinide partitioning between sorbents and solution; comparative soil extraction data; and comparative plant uptake data

  19. Use of fast reactors for actinide transmutation

    The management of radioactive waste is one of the key issues in today's discussions on nuclear energy, especially the long term disposal of high level radioactive wastes. The recycling of plutonium in liquid metal fast breeder reactors (LMFBRs) would allow 'burning' of the associated extremely long life transuranic waste, particularly actinides, thus reducing the required isolation time for high level waste from tens of thousands of years to hundreds of years for fission products only. The International Working Group on Fast Reactors (IWGFR) decided to include the topic of actinide transmutation in liquid metal fast breeder reactors in its programme. The IAEA organized the Specialists Meeting on Use of Fast Breeder Reactors for Actinide Transmutation in Obninsk, Russian Federation, from 22 to 24 September 1992. The specialists agree that future progress in solving transmutation problems could be achieved by improvements in: Radiochemical partitioning and extraction of the actinides from the spent fuel (at least 98% for Np and Cm and 99.9% for Pu and Am isotopes); technological research and development on the design, fabrication and irradiation of the minor actinides (MAs) containing fuels; nuclear constants measurement and evaluation (selective cross-sections, fission fragments yields, delayed neutron parameters) especially for MA burners; demonstration of the feasibility of the safe and economic MA burner cores; knowledge of the impact of maximum tolerable amount of rare earths in americium containing fuels. Refs, figs and tabs

  20. Research in actinide chemistry

    1991-01-01

    This report contains research results on studies of inorganic and organic complexes of actinide and lanthanide elements. Special attention is given to complexes of humic acids and to spectroscopic studies.

  1. Subsurface Biogeochemistry of Actinides

    Kersting, Annie B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Univ. Relations and Science Education; Zavarin, Mavrik [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Glenn T. Seaborg Inst.

    2016-06-29

    A major scientific challenge in environmental sciences is to identify the dominant processes controlling actinide transport in the environment. It is estimated that currently, over 2200 metric tons of plutonium (Pu) have been deposited in the subsurface worldwide, a number that increases yearly with additional spent nuclear fuel (Ewing et al., 2010). Plutonium has been shown to migrate on the scale of kilometers, giving way to a critical concern that the fundamental biogeochemical processes that control its behavior in the subsurface are not well understood (Kersting et al., 1999; Novikov et al., 2006; Santschi et al., 2002). Neptunium (Np) is less prevalent in the environment; however, it is predicted to be a significant long-term dose contributor in high-level nuclear waste. Our focus on Np chemistry in this Science Plan is intended to help formulate a better understanding of Pu redox transformations in the environment and clarify the differences between the two long-lived actinides. The research approach of our Science Plan combines (1) Fundamental Mechanistic Studies that identify and quantify biogeochemical processes that control actinide behavior in solution and on solids, (2) Field Integration Studies that investigate the transport characteristics of Pu and test our conceptual understanding of actinide transport, and (3) Actinide Research Capabilities that allow us to achieve the objectives of this Scientific Focus Area (SFA and provide new opportunities for advancing actinide environmental chemistry. These three Research Thrusts form the basis of our SFA Science Program (Figure 1).

  2. Actinide isotopic analysis systems

    This manual provides instructions and procedures for using the Lawrence Livermore National Laboratory's two-detector actinide isotope analysis system to measure plutonium samples with other possible actinides (including uranium, americium, and neptunium) by gamma-ray spectrometry. The computer program that controls the system and analyzes the gamma-ray spectral data is driven by a menu of one-, two-, or three-letter options chosen by the operator. Provided in this manual are descriptions of these options and their functions, plus detailed instructions (operator dialog) for choosing among the options. Also provided are general instructions for calibrating the actinide isotropic analysis system and for monitoring its performance. The inventory measurement of a sample's total plutonium and other actinides content is determined by two nondestructive measurements. One is a calorimetry measurement of the sample's heat or power output, and the other is a gamma-ray spectrometry measurement of its relative isotopic abundances. The isotopic measurements needed to interpret the observed calorimetric power measurement are the relative abundances of various plutonium and uranium isotopes and americium-241. The actinide analysis system carries out these measurements. 8 figs

  3. Feasibility Study of Supercritical Light Water Cooled Fast Reactors for Actinide Burning and Electric Power Production, Progress Report for Work Through September 2002, 4th Quarterly Report

    Mac Donald, Philip Elsworth

    2002-09-01

    The use of light water at supercritical pressures as the coolant in a nuclear reactor offers the potential for considerable plant simplification and consequent capital and O&M cost reduction compared with current light water reactor (LWR) designs. Also, given the thermodynamic conditions of the coolant at the core outlet (i.e. temperature and pressure beyond the water critical point), very high thermal efficiencies of the power conversion cycle are possible (i.e. up to about 45%). Because no change of phase occurs in the core, the need for steam separators and dryers as well as for BWR-type re-circulation pumps is eliminated, which, for a given reactor power, results in a substantially shorter reactor vessel and smaller containment building than the current BWRs. Furthermore, in a direct cycle the steam generators are not needed. If no additional moderator is added to the fuel rod lattice, it is possible to attain fast neutron energy spectrum conditions in a supercritical water-cooled reactor (SCWR). This type of core can make use of either fertile or fertile-free fuel and retain a hard spectrum to effectively burn plutonium and minor actinides from LWR spent fuel while efficiently generating electricity. One can also add moderation and design a thermal spectrum SCWR. The Generation IV Roadmap effort has identified the thermal spectrum SCWR (followed by the fast spectrum SCWR) as one of the advanced concepts that should be developed for future use. Therefore, the work in this NERI project is addressing both types of SCWRs.

  4. The ALMR actinide burning system

    The advanced liquid-metal reactor (ALMR) actinide burning system is being developed under the sponsorship of the US Department of Energy to bring its unique capabilities to fruition for deployment in the early 21st century. The system consists of four major parts: the reactor plant, the metal fuel and its recycle, the processing of light water reactor (LWR) spent fuel to extract the actinides, and the development of a residual waste package. This paper addresses the status and outlook for each of these four major elements. The ALMR is being developed by an industrial group under the leadership of General Electric (GE) in a cost-sharing arrangement with the US Department of Energy. This effort is nearing completion of the advanced conceptual design phase and will enter the preliminary design phase in 1994. The innovative modular reactor design stresses simplicity, economics, reliability, and availability. The design has evolved from GE's PRISM design initiative and has progressed to the final stages of a prelicensing review by the US Nuclear Regulatory Commission (NRC); a safety evaluation report is expected by the end of 1993. All the major issues identified during this review process have been technically resolved. The next design phases will focus on implementation of the basic safety philosophy of passive shutdown to a safe, stable condition, even without scram, and passive decay heat removal. Economic projections to date show that it will be competitive with non- nuclear and advanced LWR nuclear alternatives

  5. Radiochemistry and actinide chemistry

    The analysis of trace amounts of actinide elements by means of radiochemistry, is discussed. The similarities between radiochemistry and actinide chemistry, in the case of species amount by cubic cm below 1012, are explained. The parameters which allow to define what are the observable chemical reactions, are given. The classification of radionuclides in micro or macrocomponents is considered. The validity of the mass action law and the partition function in the definition of the average number of species for trace amounts, is investigated. Examples illustrating the results are given

  6. Western Pacific Regional Green Light Committee: progress and way forward

    T. Islam

    2015-03-01

    Full Text Available The Western Pacific Regional Green Light Committee (rGLC WPR was established in 2011 to promote the rational scale-up of programmatic management of drug-resistant tuberculosis (PMDT. We reflect on its achievements, consider the challenges faced, and explore its potential future role. Achievements include the supervision and support of national PMDT action plans, increased local ownership, contextualized guidance, and a strong focus on regional capacity building, as well as a greater awareness of regional challenges. Future rGLC activities should include (1 advocacy for high-level political commitment; (2 monitoring, evaluation, and supervision; (3 technical support and contextualized guidance; and (4 training, capacity building, and operational research. Regional activities require close collaboration with both national and global efforts, and should be an important component of the new Global Drug-resistant TB Initiative.

  7. Actinide recovery from pyrochemical residues

    We demonstrated a new process for recovering plutonium and americium from pyrochemical waste. The method is based on chloride solution anion exchange at low acidity, or acidity that eliminates corrosive HCl fumes. Developmental experiments of the process flow chart concentrated on molten salt extraction (MSE) residues and gave >95% plutonium and >90% americium recovery. The recovered plutonium contained 62- from high-chloride low-acid solution. Americium and other metals are washed from the ion exchange column with lN HNO3-4.8M NaCl. After elution, plutonium is recovered by hydroxide precipitation, and americium is recovered by NaHCO3 precipitation. All filtrates from the process can be discardable as low-level contaminated waste. Production-scale experiments are in progress for MSE residues. Flow charts for actinide recovery from electro-refining and direct oxide reduction residues are presented and discussed

  8. Actinide separative chemistry

    Actinide separative chemistry has focused very heavy work during the last decades. The main was nuclear spent fuel reprocessing: solvent extraction processes appeared quickly a suitable, an efficient way to recover major actinides (uranium and plutonium), and an extensive research, concerning both process chemistry and chemical engineering technologies, allowed the industrial development in this field. We can observe for about half a century a succession of Purex plants which, if based on the same initial discovery (i.e. the outstanding properties of a molecule, the famous TBP), present huge improvements at each step, for a large part due to an increased mastery of the mechanisms involved. And actinide separation should still focus R and D in the near future: there is a real, an important need for this, even if reprocessing may appear as a mature industry. We can present three main reasons for this. First, actinide recycling appear as a key-issue for future nuclear fuel cycles, both for waste management optimization and for conservation of natural resource; and the need concerns not only major actinide but also so-called minor ones, thus enlarging the scope of the investigation. Second, extraction processes are not well mastered at microscopic scale: there is a real, great lack in fundamental knowledge, useful or even necessary for process optimization (for instance, how to design the best extracting molecule, taken into account the several notifications and constraints, from selectivity to radiolytic resistivity?); and such a need for a real optimization is to be more accurate with the search of always cheaper, cleaner processes. And then, there is room too for exploratory research, on new concepts-perhaps for processing quite new fuels- which could appear attractive and justify further developments to be properly assessed: pyro-processes first, but also others, like chemistry in 'extreme' or 'unusual' conditions (supercritical solvents, sono-chemistry, could be

  9. Research progress on combat trauma treatment in cold regions

    Hui-shan WANG; Han, Jin-Song

    2014-01-01

    Cold regions are a special combat environment in which low temperatures have a great impact on human metabolism and other vital functions, including the nervous, motion, cardiovascular, circulatory, respiratory, and urinary systems; consequently, low temperatures often aggravate existing trauma, leading to high mortality rates if rapid and appropriate treatment is not provided. Hypothermia is an independent risk factor of fatality following combat trauma; therefore, proactive preventative mea...

  10. ACTINET: a European Network for Actinide Sciences

    Full text of publication follows: The research in Actinide sciences appear as a strategic issue for the future of nuclear systems. Sustainability issues are clearly in connection with the way actinide elements are managed (either addressing saving natural resource, or decreasing the radiotoxicity of the waste). The recent developments in the field of minor actinide P and T offer convincing indications of what could be possible options, possible future processes for the selective recovery of minor actinides. But they point out, too, some lacks in the basic understanding of key-issues (such as for instance the control An versus Ln selectivity, or solvation phenomena in organic phases). Such lacks could be real obstacles for an optimization of future processes, with new fuel compounds and facing new recycling strategies. This is why a large and sustainable work appears necessary, here in the field of basic actinide separative chemistry. And similar examples could be taken from other aspects of An science, for various applications (nuclear fuel or transmutation targets design, or migration issues,): future developments need a strong, enlarged, scientific basis. The Network ACTINET, established with the support of the European Commission, has the following objectives: - significantly improve the accessibility of the major actinide facilities to the European scientific community, and form a set of pooled facilities, as the corner-stone of a progressive integration process, - improve mobility between the member organisations, in particular between Academic Institutions and National Laboratories holding the pooled facilities, - merge part of the research programs conducted by the member institutions, and optimise the research programs and infrastructure policy via joint management procedures, - strengthen European excellence through a selection process of joint proposals, and reduce the fragmentation of the community by putting critical mass of resources and expertise on

  11. Progress and prospects of regional financial arrangements and cooperation in East Asia: a critical survey

    Jeon, Bang Nam

    2012-01-01

    The main purpose of this paper is to provide a brief survey for the progress and prospects of regional financial arrangements/cooperation among the East Asian nations and present the summary of various conflicting points of discussion about the strategies on the establishment of an effective regional financial arrangement in the region. This critical survey derives a list of viable and practical strategies for establishing an effective RFA/RFC scheme in the East Asian region in order to preve...

  12. Photochemistry of the actinides

    It has been found that all three major actinides have a useful variety of photochemical reactions which could be used to achieve a separations process that requires fewer reagents. Several features merit enumerating: (1) Laser photochemistry is not now as uniquely important in fuel reprocessing as it is in isotopic enrichment. The photochemistry can be successfully accomplished with conventional light sources. (2) The easiest place to apply photo-reprocessing is on the three actinides U, Pu, and Np. The solutions are potentially cleaner and more amenable to photoreactions. (3) Organic-phase photoreactions are probably not worth much attention because of the troublesome solvent redox chemistry associated with the photochemical reaction. (4) Upstream process treatment on the raffinate (dissolver solution) may never be too attractive since the radiation intensity precludes the usage of many optical materials and the nature of the solution is such that light transmission into it might be totally impossible

  13. Recovering actinide values

    Actinide values are recovered from sodium carbonate scrub waste solutions containing these and other values along with organic compounds resulting from the radiolytic and hydrolytic degradation of neutral organophosphorus extractants such as tri-n butyl phosphate (TBP) and dihexyl-N, N-diethyl carbamylmethylene phosphonate (DHDECMP) which have been used in the reprocessing of irradiated nuclear reactor fuels. The scrub waste solution is made acidic with mineral acid, to form a feed solution which is then contacted with a water-immiscible, highly polar organic extractant which selectively extracts the degradation products from the feed solution. The feed solution can then be processed to recover the actinides for storage or recycled back into the high-level waste process stream. The extractant can be recycled after stripping the degradation products with a neutral sodium carbonate solution. (author)

  14. Actinides: why are they important biologically

    The following topics are discussed: actinide elements in energy systems; biological hazards of the actinides; radiation protection standards; and purposes of actinide biological research with regard to toxicity, metabolism, and therapeutic regimens

  15. Molecular orbitual studies of the bonding in heavy element organometallics: Progress report

    Progress to date is described in 2 major areas: (1) Tris(cyclopentadienyl) actinide complexes. We have made considerable progress in our studies of the electronic structure of organoactinide compounds containing three cyclopentadienyl ligands: investigations of the ''base-free'' compounds Cp3An, and investigations of the interaction of Cp3An compounds with a fourth ligand, L. (2) Actinide-containing molecules with metal-metal bonds, actinide-actinide bonds, and actinide-transition metal bonds

  16. Photoelectron spectra of actinide compounds

    A brief overview of the application of photoelectron spectroscopy is presented for the study of actinide materials. Phenomenology as well as specific materials are discussed with illustrative examples

  17. Actinides: from heavy fermions to plutonium metallurgy

    The actinide elements mark the emergence of 5f electrons. The f electrons possess sufficiently unusual characteristics that their participation in atomic binding often result in dramatic changes in properties. This provides an excellent opportunity to study the question of localization of electrons; a question that is paramount in predicting the physical and chemical properties of d and f electron transition metals. The transition region between localized (magnetic) and itinerant (often superconducting) behavior provides for many interesting phenomena such as structural instabilities (polymorphism), spin fluctuations, mixed valences, charge density waves, exceptional catalytic activity and hydrogen storage. This region offers most interesting behavior such as that exhibited by the actinide compounds UBe13 and UPt3. Both compounds are heavy-fermion superconductors in which both magnetic and superconducting behavior exist in the same electrons. The consequences of f-electron bonding (which appears greatest at Plutonium) show dramatic effects on phase stability, alloying behavior, phase transformations and mechanical behavior

  18. Effect of the complexity of sunflower growing regions on the genetic progress achieved by breeding programs

    de la Vega A.J.

    2012-01-01

    Sunflower (Helianthus annuus L.) breeding programs typically target heterogeneous regions, where large genotype × environment interactions (GEI) complicate genetic progress. Some understanding of the underlying factors, nature and repeatability of GEIs can help to accommodate their effects. This review summarizes the findings of a series of studies conducted in Argentina with the goals of understanding the effect of GEIs on sunflower yield progress and desi...

  19. Optical techniques for actinide research

    In recent years, substantial gains have been made in the development of spectroscopic techniques for electronic properties studies. These techniques have seen relatively small, but growing, application in the field of actinide research. Photoemission spectroscopies, reflectivity and absorption studies, and x-ray techniques will be discussed and illustrative examples of studies on actinide materials will be presented

  20. Progress in health-related millennium development goals in the WHO South-East Asia Region

    Poonam Khetrapal Singh

    2012-01-01

    Full Text Available Home to 25% of the world′s population and bearing 30% of the Global disease burden, the South-East Asia Region [1] of the World Health Organization has an important role in the progress of global health. Three of the eight million development goal (MDG goals that relate to health are MDG 4, 5, and 6. There is progress in all three goals within the countries of the region, although the progress varies across countries and even within countries. With concerted and accelerated efforts in some countries and certain specific areas, the region will achieve the targets of the three health MDGs. The key challenges are in sustainable scaling up of evidence-based interventions to improve maternal and child health and controlling communicable diseases. This will require continued focus and investments in strengthening health systems that provide individual and family centered comprehensive package of interventions with equitable reach and that which is provided free at the point of service delivery. Important lessons that have been learnt in implementing the MDG agenda in the past two decades will inform setting up of the post MDG global health agenda. This article provides a snap shot of progress thus far, key challenges and opportunities in WHO South-East Asia Region and lays down the way forward for the global health agenda post 2015.

  1. Radioecology of the actinide elements

    Research progress is reported in sections entitled: scope of studies supported by the Department of Energy; oxidation state diagrams are a potential tool for studying the redox chemistry of Pu in natural waters; studies are initiated to investigate the effect of pH and organic matter on the distribution coefficients of Cm with natural sediments; the relative distributions of resuspended and direct deposited Pu in a corn canopy are quantified; the retention of Pu surface contamination by corn plants is being studied; Pu concentrations in tobacco are being determined; concentrations of Pu per unit mass and per unit surface area are compared for subterranean crops; models of Pu behavior in agricultural crops are being validated; distribution of aerially released Pu in loblolly pine plantations is independent of deposition rate; investigation of the effects of chelate and redox potential of the uptake of Pu and Cm by rice is underway; studies of Cm cycling in a floodplain forest have been initiated; the effects of unusually large Pu deposition onto a wheat ecosystem are being studied using computer simulations; long-term kinetic models of Pu behavior in plant-soil systems are being developed; scope of studies supported by the Nuclear Regulatory Commission; growth form of broadleaf crop may affect Pu contents; root uptake of Pu and Cm measured for rice root uptake of Pu and Cm measured for rice; long-term actinide uptake study is continuing at SREL; and uranium cycling in major southeastern agricultural crops being studied

  2. Actinide elements in aquatic and terrestrial environments

    Progress is reported in terrestrial ecology studies with regard to plutonium in biota from the White Oak Creek forest; comparative distribution of plutonium in two forest ecosystems; an ecosystem model of plutonium dynamics; actinide element metabolism in cotton rats; and crayfish studies. Progress is reported in aquatic studies with regard to transuranics in surface waters, frogs, benthic algae, and invertebrates from pond 3513; and radioecology of transuranic elements in cotton rats bordering waste pond 3513. Progress is also reported in stability of trivalent plutonium in White Oak Lake water; chemistry of plutonium, americium, curium, and uranium in pond water; uranium, thorium, and plutonium in small mammals; and effect of soil pretreatment on the distribution of plutonium

  3. Managing Inventories of Heavy Actinides

    The Department of Energy (DOE) has stored a limited inventory of heavy actinides contained in irradiated targets, some partially processed, at the Savannah River Site (SRS) and Oak Ridge National Laboratory (ORNL). The 'heavy actinides' of interest include plutonium, americium, and curium isotopes; specifically 242Pu and 244Pu, 243Am, and 244/246/248Cm. No alternate supplies of these heavy actinides and no other capabilities for producing them are currently available. Some of these heavy actinide materials are important for use as feedstock for producing heavy isotopes and elements needed for research and commercial application. The rare isotope 244Pu is valuable for research, environmental safeguards, and nuclear forensics. Because the production of these heavy actinides was made possible only by the enormous investment of time and money associated with defense production efforts, the remaining inventories of these rare nuclear materials are an important part of the legacy of the Nuclear Weapons Program. Significant unique heavy actinide inventories reside in irradiated Mark-18A and Mark-42 targets at SRS and ORNL, with no plans to separate and store the isotopes for future use. Although the costs of preserving these heavy actinide materials would be considerable, for all practical purposes they are irreplaceable. The effort required to reproduce these heavy actinides today would likely cost billions of dollars and encompass a series of irradiation and chemical separation cycles for at least 50 years; thus, reproduction is virtually impossible. DOE has a limited window of opportunity to recover and preserve these heavy actinides before they are disposed of as waste. A path forward is presented to recover and manage these irreplaceable National Asset materials for future use in research, nuclear forensics, and other potential applications.

  4. Concentration of actinides in the food chain

    Considerable concern is now being expressed over the discharge of actinides into the environment. This report presents a brief review of the chemistry of the actinides and examines the evidence for interaction of the actinides with some naturally-occurring chelating agents and other factors which might stimulate actinide concentration in the food chain of man. This report also reviews the evidence for concentration of actinides in plants and for uptake through the gastrointestinal tract. (author)

  5. Calorimetric assay of minor actinides

    Rudy, C.; Bracken, D.; Cremers, T.; Foster, L.A.; Ensslin, N.

    1996-12-31

    This paper reviews the principles of calorimetric assay and evaluates its potential application to the minor actinides (U-232-4, Am-241, Am- 243, Cm-245, Np-237). We conclude that calorimetry and high- resolution gamma-ray isotopic analysis can be used for the assay of minor actinides by adapting existing methodologies for Pu/Am-241 mixtures. In some cases, mixtures of special nuclear materials and minor actinides may require the development of new methodologies that involve a combination of destructive and nondestructive assay techniques.

  6. Calorimetric assay of minor actinides

    This paper reviews the principles of calorimetric assay and evaluates its potential application to the minor actinides (U-232-4, Am-241, Am- 243, Cm-245, Np-237). We conclude that calorimetry and high- resolution gamma-ray isotopic analysis can be used for the assay of minor actinides by adapting existing methodologies for Pu/Am-241 mixtures. In some cases, mixtures of special nuclear materials and minor actinides may require the development of new methodologies that involve a combination of destructive and nondestructive assay techniques

  7. Systematic view of optical absorption spectra in the actinide series

    In recent years sufficient new spectra of actinides in their numerous valence states have been measured to encourage a broader scale analysis effort than was attempted in the past. Theoretical modelling in terms of effective operators has also undergone development. Well established electronic structure parameters for the trivalent actinides are being used as a basis for estimating parameters in other valence states and relationships to atomic spectra are being extended. Recent contributions to our understanding of the spectra of 4+ actinides have been particularly revealing and supportive of a developing general effort to progress beyond a preoccupation with modelling structure to consideration of the much broader area of structure-bonding relationships. We summarize here both the developments in modelling electronic structure and the interpretation of apparent trends in bonding. 60 refs., 9 figs., 1 tab

  8. Actinides and the environment

    The book combines in one volume the opinions of experts regarding the interaction of radionuclides with the environment and possible ways to immobilize and dispose of nuclear waste. The relevant areas span the spectrum from pure science, such as the fundamental physics and chemistry of the actinides, geology, environmental transport mechanisms, to engineering issues such as reactor operation and the design of nuclear waste repositories. The cross-fertilization between these various areas means that the material in the book will be accessible to seasoned scientists who may wish to obtain an overview of the current state of the art in the field of environmental remediation of radionuclides, as well as to beginning scientists embarking on a career in this field. refs

  9. Environmental research on actinide elements

    The papers synthesize the results of research sponsored by DOE's Office of Health and Environmental Research on the behavior of transuranic and actinide elements in the environment. Separate abstracts have been prepared for the 21 individual papers

  10. Properties of minor actinide nitrides

    The present status of the research on properties of minor actinide nitrides for the development of an advanced nuclear fuel cycle based on nitride fuel and pyrochemical reprocessing is described. Some thermal stabilities of Am-based nitrides such as AmN and (Am, Zr)N were mainly investigated. Stabilization effect of ZrN was cleary confirmed for the vaporization and hydrolytic behaviors. New experimental equipments for measuring thermal properties of minor actinide nitrides were also introduced. (author)

  11. Papillary tumor of the pineal region: report of a rapidly progressive tumor with possible multicentric origin

    Sato, Takashi S. [University of Iowa, Carver College of Medicine, Iowa City, IA (United States); Kirby, Patricia A. [University of Iowa, Department of Pathology, Iowa City, IA (United States); Buatti, John M. [University of Iowa, Department of Radiation Oncology, Iowa City, IA (United States); Moritani, Toshio [University of Iowa Hospitals and Clinics, Department of Radiology, Iowa City, IA (United States)

    2009-02-15

    Papillary tumor of the pineal region (PTPR) is an uncommon tumor recently added to the WHO classification of CNS tumors. We report a case of PTPR in a young boy that was noteworthy for early CSF dissemination and relentless progression. In spite of intensive chemotherapy and comprehensive radiotherapy, the boy died. The neuroimaging appearance is unique with possible multicentric origin of the tumor and intense uptake of {sup 111}In-DTPA-pentetreotide. (orig.)

  12. ARE. Regional energy supplies - progress report 2000-2001; ARE. Regionale Energieversorgung 2000-2001. Taetigkeitsbericht

    NONE

    2002-05-01

    The ARE progress report discusses the following issues: Economic development and its effects on power supply; Deregulation of the electricity and gas market; Competition between regional utilities; Energy policy of the new German government; European regulations; Legislation on energy supply; Energy supply and cartel law; Regional supply in the East German states. [German] Der Taetigkeitsbericht der ARE befasst sich mit folgenden Themen: Gesamtwirtschaftliche Entwicklung und ihre Auswirkung auf die Energiewirtschaft, Oeffnung des Monopoles fuer Strom und Gas, Wettbewerb der regionalen Energieversorger, Energiepolitik der neuen Bundesregierung, Europaeische Richtlininen, energiewirtschaftsrecht, Versorgungswirtschaft und Kartellrecht und der Regionalversorgung in den neuen Bundeslaendern.

  13. COMPETITIVENESS AND INNOVATION IN THE ROMANIAN REGIONS – HOW MUCH PROGRESS DURING THE POST- ACCESSION PERIOD?

    Carmen\tBeatrice\tPAUNA

    2015-06-01

    Full Text Available The paper aims to assess the latest developments in the competitiveness of the Romanian regions, with a particular focus on innovation as one of its key determinants. Different sets of indicators are used and comparisons with the EU countries and their regions are provided. The results reveal some progress towards better competitive positioning, but little advancement in the field of innovation in most of the Romanian regions (below 50% of the EU average. This exposes a systemic weakness of the innovation process in Romania, determined by both the national RDI system and the business sector, which calls for sustained efforts at multiple levels (political, economic, institutional, social, entrepreneurial, both nationally and regionally to overcome the current stagnation and push strongly towards the most needed change in mindsets and actions in the near future.

  14. Status of nuclear data for actinides

    Guzhovskii, B.Y.; Gorelov, V.P.; Grebennikov, A.N. [Russia Federal Nuclear Centre, Arzamas (Russian Federation)] [and others

    1995-10-01

    Nuclear data required for transmutation problem include many actinide nuclei. In present paper the analysis of neutron fission, capture, (n,2n) and (n,3n) reaction cross sections at energy region from thermal point to 14 MeV was carried out for Th, Pa, U, Np, Pu, Am and Cm isotops using modern evaluated nuclear data libraries and handbooks of recommended nuclear data. Comparison of these data indicates on substantial discrepancies in different versions of files, that connect with quality and completeness of original experimental data.

  15. Fission cross section measurements for minor actinides

    Fursov, B. [IPPE, Obninsk (Russian Federation)

    1997-03-01

    The main task of this work is the measurement of fast neutron induced fission cross section for minor actinides of {sup 238}Pu, {sup 242m}Am, {sup 243,244,245,246,247,248}Cm. The task of the work is to increase the accuracy of data in MeV energy region. Basic experimental method, fissile samples, fission detectors and electronics, track detectors, alpha counting, neutron generation, fission rate measurement, corrections to the data and error analysis are presented in this paper. (author)

  16. THERMODYNAMICS OF THE ACTINIDES

    Cunningham, Burris B.

    1962-04-01

    Recent work on the thermodynamic properties of the transplutonium elements is presented and discussed in relation to trends in thermodynamic properties of the actinide series. Accurate values are given for room temperature lattice parameters of two crystallographic forms, (facecentred cubic) fcc and dhcp (double-hexagonal closepacked), of americium metal and for the coefficients of thermal expansion between 157 and 878 deg K (dhcp) and 295 to 633 deg K (fcc). The meiting point of the metal, and its magnetic susceptibility between 77 and 823 deg K are reported and the latter compared with theoretical values for the tripositive ion calculated from spectroscopic data. Similar data (crystallography, meiting point and magnetic susceptibility) are given for metallic curium. A value for the heat of formation of americium monoxide is reported in conjunction with crystallographic data on the monoxide and mononitride. A revision is made in the current value for the heat of formation of Am/O/sub 2/ and for the potential of the Am(III)-Am(IV) couple. The crystal structures and lattice parameters are reported for the trichloride, oxychloride and oxides of californium. (auth)

  17. Regional Fertility Transition in India: An Analysis Using Synthetic Parity Progression Ratios

    Thomas Spoorenberg

    2012-01-01

    Full Text Available This paper examines various aspects of regional fertility transition in India. Using nationally representative data from three rounds of National Family Health Surveys (NFHSs conducted in India, we compare and contrast fertility patterns in six regions of India for the period between 1977 and 2004. To study the fertility patterns, we use synthetic parity progression ratios which, besides providing estimates for average lifetime parity, also allow for decomposition of lifetime parity by birth order. The paper also examines changes in birth intervals over time and across the six regions. The results confirm the persistence of regional differences in fertility. However, in all regions fertility is declining and it is possible that fertility rates will converge in the near future. The main reason for fertility decline in all regions is the reduction in third- and higher-order births. There has not been any significant decline in first and second births, even in regions with low fertility. In addition to the discussion of the substantive results, the paper also comments on the quality of NFHS data.

  18. Actinide burning and waste disposal

    Here we review technical and economic features of a new proposal for a synergistic waste-management system involving reprocessing the spent fuel otherwise destined for a U.S. high-level waste repository and transmuting the recovered actinides in a fast reactor. The proposal would require a U.S. fuel reprocessing plant, capable of recovering and recycling all actinides, including neptunium americium, and curium, from LWR spent fuel, at recoveries of 99.9% to 99.999%. The recovered transuranics would fuel the annual introduction of 14 GWe of actinide-burning liquid-metal fast reactors (ALMRs), beginning in the period 2005 to 2012. The new ALMRs would be accompanied by pyrochemical reprocessing facilities to recover and recycle all actinides from discharged ALMR fuel. By the year 2045 all of the LWR spent fuel now destined f a geologic repository would be reprocessed. Costs of constructing and operating these new reprocessing and reactor facilities would be borne by U.S. industry, from the sale of electrical energy produced. The ALMR program expects that ALMRs that burn actinides from LWR spent fuel will be more economical power producers than LWRs as early as 2005 to 2012, so that they can be prudently selected by electric utility companies for new construction of nuclear power plants in that era. Some leaders of DOE and its contractors argue that recovering actinides from spent fuel waste and burning them in fast reactors would reduce the life of the remaining waste to about 200-300 years, instead of 00,000 years. The waste could then be stored above ground until it dies out. Some argue that no geologic repositories would be needed. The current view expressed within the ALMR program is that actinide recycle technology would not replace the need for a geologic repository, but that removing actinides from the waste for even the first repository would simplify design and licensing of that repository. A second geologic repository would not be needed. Waste now planned

  19. Progress toward poliomyelitis eradication -- Western Pacific Region, January 1, 1996-September 27, 1997.

    1997-11-28

    In 1988, the World Health Assembly adopted the goal of global poliomyelitis eradication by 2000, which was endorsed in each of the six regions of the World Health Organization (WHO). In the Western Pacific Region (WPR), where the last known case of polio associated with isolation of wild poliovirus occurred in March 1997, the reported number of cases decreased from 5963 in 1990 to 197 in 1996. This report documents progress toward polio eradication in WPR from January 1, 1996, through September 27, 1997, in countries where polio is endemic (Cambodia, China, Laos, Papua New Guinea, Philippines, and Vietnam) or recently was endemic (Malaysia and Mongolia) and describes the routine and supplemental vaccination activities necessary to interrupt wild poliovirus transmission in the region. PMID:9393657

  20. Kinetics of actinide complexation reactions

    Though the literature records extensive compilations of the thermodynamics of actinide complexation reactions, the kinetics of complex formation and dissociation reactions of actinide ions in aqueous solutions have not been extensively investigated. In light of the central role played by such reactions in actinide process and environmental chemistry, this situation is somewhat surprising. The authors report herein a summary of what is known about actinide complexation kinetics. The systems include actinide ions in the four principal oxidation states (III, IV, V, and VI) and complex formation and dissociation rates with both simple and complex ligands. Most of the work reported was conducted in acidic media, but a few address reactions in neutral and alkaline solutions. Complex formation reactions tend in general to be rapid, accessible only to rapid-scan and equilibrium perturbation techniques. Complex dissociation reactions exhibit a wider range of rates and are generally more accessible using standard analytical methods. Literature results are described and correlated with the known properties of the individual ions

  1. 33rd Actinide Separations Conference

    McDonald, L M; Wilk, P A

    2009-05-04

    Welcome to the 33rd Actinide Separations Conference hosted this year by the Lawrence Livermore National Laboratory. This annual conference is centered on the idea of networking and communication with scientists from throughout the United States, Britain, France and Japan who have expertise in nuclear material processing. This conference forum provides an excellent opportunity for bringing together experts in the fields of chemistry, nuclear and chemical engineering, and actinide processing to present and discuss experiences, research results, testing and application of actinide separation processes. The exchange of information that will take place between you, and other subject matter experts from around the nation and across the international boundaries, is a critical tool to assist in solving both national and international problems associated with the processing of nuclear materials used for both defense and energy purposes, as well as for the safe disposition of excess nuclear material. Granlibakken is a dedicated conference facility and training campus that is set up to provide the venue that supports communication between scientists and engineers attending the 33rd Actinide Separations Conference. We believe that you will find that Granlibakken and the Lake Tahoe views provide an atmosphere that is stimulating for fruitful discussions between participants from both government and private industry. We thank the Lawrence Livermore National Laboratory and the United States Department of Energy for their support of this conference. We especially thank you, the participants and subject matter experts, for your involvement in the 33rd Actinide Separations Conference.

  2. Decorporation of inhaled actinides by chelation therapy

    This article describes recent work in NRPB laboratories that has identified some of the factors influencing the behaviour of plutonium, americium and curium compounds in the body after inhalation, together with a number of experimental approaches that are being developed to optimise their treatment with DTPA. It is concluded that the most effective treatment has yet to be developed, but progress must depend on a better understanding of the factors governing the transport of actinides in the body. It cannot be assumed that because the inhaled material is readily translocated to blood, that treatment regimens with Ca-DTPA based solely on previous understanding of the metabolic fate of soluble actinide complexes will be successful. In fact, depending on the nature of the material involved in the accident, inhalation alone or combined with prolonged infusion of DTPA may be more effective than the periodic intravenous injections of the chelating agent alone. For poorly transportable materials such as insoluble plutonium-239 dioxide, chelation treatment remains essentially ineffective. (U.K.)

  3. Volumetric MRI for evaluation of regional pattern and progression of neocortical degeneration in Alzheimer's disease

    Volumetric analysis of the corpus callosum and hippocampus using MRI in Alzheimer's disease (AD) to evaluate the regional pattern and progression of neocortical neurodegeneration. In subsequent studies we investigated patients with AD and healthy controls. Volumetry was based on MRI-data from a sagittal 3D T1w-gradient echo sequence. The corpus callosum (CC) was measured in a midsagittal slice, and subdivided into 5 subregions. Volumetry of the hippocampus/amygdala-formation (HAF) was performed by segmentation in coronary reoriented slices. In AD patients we found a significant atrophy in the rostrum und splenium of CC. The atrophy was correlated with the severity of dementia, but no correlation was found with the load of white matter lesions. In comparison with 18FDG-PET, we found a significant correlation of regional CC-atrophy with the regional decline of cortical glucose metabolism. A ROC-analysis demonstrated no significant differences in the diagostic accuracy of HAF volumetry and regional CC volumetry of the splenium (region C5) even in mild stages of dementia. Regional atrophy of CC can be used as a marker of neocortical degeneration even in early stages of dementia in AD. (orig.)

  4. Thermal-hydraulics of actinide burner reactors

    As a part of conceptual study of actinide burner reactors, core thermal-hydraulic analyses were conducted for two types of reactor concepts, namely (1) sodium-cooled actinide alloy fuel reactor, and (2) helium-cooled particle-bed reactor, to examine the feasibility of high power-density cores for efficient transmutation of actinides within the maximum allowable temperature limits of fuel and cladding. In addition, calculations were made on cooling of actinide fuel assembly. (author)

  5. Actinides and Life's Origins.

    Adam, Zachary

    2007-12-01

    There are growing indications that life began in a radioactive beach environment. A geologic framework for the origin or support of life in a Hadean heavy mineral placer beach has been developed, based on the unique chemical properties of the lower-electronic actinides, which act as nuclear fissile and fertile fuels, radiolytic energy sources, oligomer catalysts, and coordinating ions (along with mineralogically associated lanthanides) for prototypical prebiotic homonuclear and dinuclear metalloenzymes. A four-factor nuclear reactor model was constructed to estimate how much uranium would have been required to initiate a sustainable fission reaction within a placer beach sand 4.3 billion years ago. It was calculated that about 1-8 weight percent of the sand would have to have been uraninite, depending on the weight percent, uranium enrichment, and quantity of neutron poisons present within the remaining placer minerals. Radiolysis experiments were conducted with various solvents with the use of uraniumand thorium-rich minerals (metatorbernite and monazite, respectively) as proxies for radioactive beach sand in contact with different carbon, hydrogen, oxygen, and nitrogen reactants. Radiation bombardment ranged in duration of exposure from 3 weeks to 6 months. Low levels of acetonitrile (estimated to be on the order of parts per billion in concentration) were conclusively identified in 2 setups and tentatively indicated in a 3(rd) by gas chromatography/mass spectrometry. These low levels have been interpreted within the context of a Hadean placer beach prebiotic framework to demonstrate the promise of investigating natural nuclear reactors as power production sites that might have assisted the origins of life on young rocky planets with a sufficiently differentiated crust/mantle structure. Future investigations are recommended to better quantify the complex relationships between energy release, radioactive grain size, fissionability, reactant phase, phosphorus

  6. Accelerating regional atrophy rates in the progression from normal aging to Alzheimer's disease

    Sluimer, Jasper D. [VU University Medical Centre, Department of Diagnostic Radiology, Amsterdam (Netherlands); VU University Medical Centre, Alzheimer Centre, Amsterdam (Netherlands); VU University Medical Centre, Image Analysis Centre, Amsterdam (Netherlands); VU University Medical Centre, Department of Diagnostic Radiology and Alzheimer Centre, PO Box 7057, Amsterdam (Netherlands); Flier, Wiesje M. van der; Scheltens, Philip [VU University Medical Centre, Alzheimer Centre, Amsterdam (Netherlands); VU University Medical Centre, Department of Neurology, Amsterdam (Netherlands); Karas, Giorgos B.; Barkhof, Frederik [VU University Medical Centre, Department of Diagnostic Radiology, Amsterdam (Netherlands); VU University Medical Centre, Alzheimer Centre, Amsterdam (Netherlands); VU University Medical Centre, Image Analysis Centre, Amsterdam (Netherlands); Schijndel, Ronald van [VU University Medical Centre, Image Analysis Centre, Amsterdam (Netherlands); VU University Medical Centre, Department of Informatics, Amsterdam (Netherlands); Barnes, Josephine; Boyes, Richard G. [UCL, Institute of Neurology, Dementia Research Centre, London (United Kingdom); Cover, Keith S. [VU University Medical Centre, Department of Physics and Medical Technology, Amsterdam (Netherlands); Olabarriaga, Silvia D. [University of Amsterdam, Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Centre, Amsterdam (Netherlands); Fox, Nick C. [VU University Medical Centre, Department of Neurology, Amsterdam (Netherlands); UCL, Institute of Neurology, Dementia Research Centre, London (United Kingdom); Vrenken, Hugo [VU University Medical Centre, Alzheimer Centre, Amsterdam (Netherlands); VU University Medical Centre, Image Analysis Centre, Amsterdam (Netherlands); VU University Medical Centre, Department of Physics and Medical Technology, Amsterdam (Netherlands)

    2009-12-15

    We investigated progression of atrophy in vivo, in Alzheimer's disease (AD), and mild cognitive impairment (MCI). We included 64 patients with AD, 44 with MCI and 34 controls with serial MRI examinations (interval 1.8 {+-} 0.7 years). A nonlinear registration algorithm (fluid) was used to calculate atrophy rates in six regions: frontal, medial temporal, temporal (extramedial), parietal, occipital lobes and insular cortex. In MCI, the highest atrophy rate was observed in the medial temporal lobe, comparable with AD. AD patients showed even higher atrophy rates in the extramedial temporal lobe. Additionally, atrophy rates in frontal, parietal and occipital lobes were increased. Cox proportional hazard models showed that all regional atrophy rates predicted conversion to AD. Hazard ratios varied between 2.6 (95% confidence interval (CI) = 1.1-6.2) for occipital atrophy and 15.8 (95% CI = 3.5-71.8) for medial temporal lobe atrophy. In conclusion, atrophy spreads through the brain with development of AD. MCI is marked by temporal lobe atrophy. In AD, atrophy rate in the extramedial temporal lobe was even higher. Moreover, atrophy rates also accelerated in parietal, frontal, insular and occipital lobes. Finally, in nondemented elderly, medial temporal lobe atrophy was most predictive of progression to AD, demonstrating the involvement of this region in the development of AD. (orig.)

  7. Accelerating regional atrophy rates in the progression from normal aging to Alzheimer's disease

    We investigated progression of atrophy in vivo, in Alzheimer's disease (AD), and mild cognitive impairment (MCI). We included 64 patients with AD, 44 with MCI and 34 controls with serial MRI examinations (interval 1.8 ± 0.7 years). A nonlinear registration algorithm (fluid) was used to calculate atrophy rates in six regions: frontal, medial temporal, temporal (extramedial), parietal, occipital lobes and insular cortex. In MCI, the highest atrophy rate was observed in the medial temporal lobe, comparable with AD. AD patients showed even higher atrophy rates in the extramedial temporal lobe. Additionally, atrophy rates in frontal, parietal and occipital lobes were increased. Cox proportional hazard models showed that all regional atrophy rates predicted conversion to AD. Hazard ratios varied between 2.6 (95% confidence interval (CI) = 1.1-6.2) for occipital atrophy and 15.8 (95% CI = 3.5-71.8) for medial temporal lobe atrophy. In conclusion, atrophy spreads through the brain with development of AD. MCI is marked by temporal lobe atrophy. In AD, atrophy rate in the extramedial temporal lobe was even higher. Moreover, atrophy rates also accelerated in parietal, frontal, insular and occipital lobes. Finally, in nondemented elderly, medial temporal lobe atrophy was most predictive of progression to AD, demonstrating the involvement of this region in the development of AD. (orig.)

  8. ALMR potential for actinide consumption

    The Advanced Liquid Metal Reactor (ALMR) is a US Department of Energy (DOE) sponsored fast reactor design based on the Power Reactor, Innovative Small Module (PRISM) concept originated by General Electric. This reactor combines a high degree of passive safety characteristics with a high level of modularity and factory fabrication to achieve attractive economics. The current reference design is a 471 MWt modular reactor fueled with ternary metal fuel. This paper discusses actinide transmutation core designs that fit the design envelope of the ALMR and utilize spent LWR fuel as startup material and for makeup. Actinide transmutation may be accomplished in the ALMR core by using either a breeding or burning configuration. Lifetime actinide mass consumption is calculated as well as changes in consumption behavior throughout the lifetime of the reactor. Impacts on system operational and safety performance are evaluated in a preliminary fashion. Waste disposal impacts are discussed. (author)

  9. Calculations of neutron and proton induced reaction cross sections for actinides in the energy region from 10MeV to 1GeV

    Several nuclear model codes were applied to calculations of nuclear data in the energy region from 10MeV to 1GeV. At energies up to 100MeV the nuclear theory code GNASH was used for nuclear data calculation for neutrons incident for on 238U, 233-236U, 238-242Pu, 237Np, 232Th, 241-243Am and 242-247Cm. At energies from 100MeV to 1GeV the intranuclear cascade exciton model including the fission process was applied to calculations of protons and neutrons with 233U, 235U, 238U, 232Th, 232Pa, 237Np, 238Np, 239Pu, 241Am, 242Am and 242-248Cm. Determination of parameter systematics was a major effort in the present work that was aimed at improving the predictive capability of the models used. An emphasis was placed upon a simultaneous analysis of data for a variety of reaction channels for the nuclei considered, as well as of data that are available for nearby nuclei or for other incident particles. Comparisons with experimental data available on multiple reaction cross sections, isotope yields, fission cross sections, particle multiplicities, secondary particle spectra, and double differential cross sections indicate that the calculations reproduce the trends, and often the details, of the measurements data. (author) 82 refs

  10. Actinide cation-cation complexes

    The +5 oxidation state of U, Np, Pu, and Am is a linear dioxo cation (AnO2+) with a formal charge of +1. These cations form complexes with a variety of other cations, including actinide cations. Other oxidation states of actinides do not form these cation-cation complexes with any cation other than AnO2+; therefore, cation-cation complexes indicate something unique about AnO2+ cations compared to actinide cations in general. The first cation-cation complex, NpO2+·UO22+, was reported by Sullivan, Hindman, and Zielen in 1961. Of the four actinides that form AnO2+ species, the cation-cation complexes of NpO2+ have been studied most extensively while the other actinides have not. The only PuO2+ cation-cation complexes that have been studied are with Fe3+ and Cr3+ and neither one has had its equilibrium constant measured. Actinides have small molar absorptivities and cation-cation complexes have small equilibrium constants; therefore, to overcome these obstacles a sensitive technique is required. Spectroscopic techniques are used most often to study cation-cation complexes. Laser-Induced Photacoustic Spectroscopy equilibrium constants for the complexes NpO2+·UO22+, NpO2+·Th4+, PuO2+·UO22+, and PuO2+·Th4+ at an ionic strength of 6 M using LIPAS are 2.4 ± 0.2, 1.8 ± 0.9, 2.2 ± 1.5, and ∼0.8 M-1

  11. Orbital effects in actinide systems

    Actinide magnetism presents a number of important challenges; in particular, the proximity of 5f band to the Fermi energy gives rise to strong interaction with both d and s like conduction electrons, and the extended nature of the 5f electrons means that they can interact with electron orbitals from neighboring atoms. Theory has recently addressed these problems. Often neglected, however, is the overwhelming evidence for large orbital contributions to the magnetic properties of actinides. Some experimental evidence for these effects are presented briefly in this paper. They point, clearly incorrectly, to a very localized picture for the 5f electrons. This dichotomy only enhances the nature of the challenge

  12. Fabrication of actinide mononitride fuel

    Fabrication of actinide mononitride fuel in JAERI is summarized. Actinide mononitride and their solid solutions were fabricated by carbothermic reduction of the oxides in N2 or N2-H2 mixed gas stream. Sintering study was also performed for the preparation of pellets for the property measurements and irradiation tests. The products were characterized to be high-purity mononitride with a single phase of NaCl-type structure. Moreover, fuel pins containing uranium-plutonium mixed nitride pellets were fabricated for the irradiation tests in JMTR and JOYO. (author)

  13. Actinide transmutation using inert matrix fuels versus recycle in a low conversion fast burner reactor

    infinite fuel residence time. In previous work we have shown that the amount of fluence required to achieve a unit of burnup in yttrium stabilized ZrO2 based IMF with 85 w/o zirconium oxide and 15 w/o minor actinides (MA) and plutonium increases dramatically beyond 750 MWd/kgIHM (75% burnup). In this paper we discuss the repository implications for recycle of actinides in LWR's using this type of IMF and compare this to actinide recycle in a low conversion fast burner reactor. We perform the analysis over a finite horizon of 100 years, in which reprocessing of spent LWR fuel begins in 2020. Reference [1] C. Lombardi and A. Mazzola, Exploiting the plutonium stockpiles in PWRs by using inert matrix fuel, Annals of Nuclear Energy. 23 (1996) 1117-1126. [2] U. Kasemeyer, J.M. Paratte, P. Grimm and R. Chawla, Comparison of pressurized water reactor core characteristics for 100% plutonium-containing loadings, Nuclear Technology. 122 (1998) 52-63. [3] G. Ledergerber, C. Degueldre, P. Heimgartner, M.A. Pouchon and U. Kasemeyer, Inert matrix fuel for the utilisation of plutonium, Progress in Nuclear Energy. 38 (2001) 301-308. [4] U. Kasemeyer, C. Hellwig, J. Lebenhaft and R. Chawla, Comparison of various partial light water reactor core loadings with inert matrix and mixed oxide fuel, Journal of Nuclear Materials. 319 (2003) 142-153. [5] E.A. Schneider, M.R. Deinert and K.B. Cady, Burnup simulations of an inert matrix fuel using a two region, multi-group reactor physics model, in Proceedings of the physics of advanced fuel cycles, PHYSOR 2006, Vancouver, BC, 2006. [6] E.A. Schneider, M.R. Deinert and K.B. Cady, Burnup simulations and spent fuel characteristics of ZRO2 based inert matrix fuels, Journal of Nuclear Materials. 361 (2007) 41-51. (authors)

  14. High beta and second region stability analysis and ICRF edge modeling: Progress report

    This report describes the tasks accomplished under Department of Energy contract No. FG02-86ER53236 in modeling the edge plasma- antenna interaction that occurs during Ion Cyclotron Range of Frequency (ICRF) heating. This work has resulted in the development of several codes which determine kinetic and fluid modifications to the edge plasma. When used in combination, these codes predict the level of impurity generation observed in experiments on the Princeton Large Torus. In addition, these models suggest improvements to the design of ICRF antennas. Also described is progress made on high beta and second region analysis. Code development for a comprehensive infernal mode analysis code is nearing completion. A method has been developed for parameterizing the second region of stability and is applied to circular cross section tokamaks. Various studies for high beta experimental devices such as PBX-M and DIII-D have been carried out and are reported on. 19 refs., 8 figs., 1 tab

  15. [FY 2014 progress report]: Bird Communities of Coniferous Forests in the Acadian Region: Their Responses to Management and Habitat Associations

    US Fish and Wildlife Service, Department of the Interior — This FY2014 progress report documents project activities for bird communities of coniferous forests in the Acadian Region. The goal of the project is to examine...

  16. Research on the chemical speciation of actinides

    A demand for the safe and effective management of spent nuclear fuel and radioactive waste generated from nuclear power plant draws increasing attention with the growth of nuclear power industry. The objective of this project is to establish the basis of research on the actinide chemistry by using advanced laser-based highly sensitive spectroscopic systems. Researches on the chemical speciation of actinides are prerequisite for the development of technologies related to nuclear fuel cycles, especially, such as the safe management of high level radioactive wastes and the chemical examination of irradiated nuclear fuels. For supporting these technologies, laser-based spectroscopies have been performed for the chemical speciation of actinide in an aqueous solutions and the quantitative analysis of actinide isotopes in spent nuclear fuels. In this report, results on the following subjects have been summarized. (1) Development of TRLFS technology for chemical speciation of actinides, (2) Development of LIBD technology for measuring solubility of actinides, (3) Chemical speciation of plutonium complexes by using a LWCC system, (4) Development of LIBS technology for the quantitative analysis of actinides, (5) Development of technology for the chemical speciation of actinides by CE, (6) Evaluation on the chemical reactions between actinides and humic substances, (7) Chemical speciation of actinides adsorbed on metal oxides surfaces, (8) Determination of actinide source terms of spent nuclear fuel

  17. Environmental research on actinide elements

    Pinder, J.E. III; Alberts, J.J.; McLeod, K.W.; Schreckhise, R.G. (eds.)

    1987-08-01

    The papers synthesize the results of research sponsored by DOE's Office of Health and Environmental Research on the behavior of transuranic and actinide elements in the environment. Separate abstracts have been prepared for the 21 individual papers. (ACR)

  18. ENDF/B-V actinides

    This document summarizes the contents of the actinides part of the ENDF/B-V nuclear data library released by the US National Nuclear Data Center. This library or selective retrievals of it, are available from the IAEA Nuclear Data Section. (author)

  19. ACTINET: Establishment of a network of excellence for actinide sciences

    activities in actinide sciences in Europe. The Network of Excellence ACTINET-6 established in the framework of the specific programme EURATOM, will be used to launch a sustainable network gathering a number of institutions, ranging from large National Laboratories to University Departments, within the broad area of actinide sciences, with the following objectives: - significantly improve the accessibility of the major actinide facilities to the European scientific community, and form a set of pooled facilities that will evolve to a multi-site user facility, as the corner-stone of a progressive integration process, - improve mobility between the member organisations, in particular between Academic Institutions and National Laboratories holding the pooled facilities, - merge part of the research programs conducted by the member institutions, and optimise the research programs and infrastructure policy via joint management procedures, - strengthen European excellence through a selection process of joint proposals, and reduce the fragmentation of the community by putting critical mass of resources and expertise on shared challenges, in order for Europe to remain or become a world-force in the fields of actinide sciences. (authors)

  20. Neutrons scattering studies in the actinide region

    During the report period were investigated the following areas: prompt fission neutron energy spectra measurements; neutron elastic and inelastic scattering from 239Pu; neutron scattering in 181Ta and 197Au; response of a 235U fission chamber near reaction thresholds; two-parameter data acquisition system; ''black'' neutron detector; investigation of neutron-induced defects in silicon dioxide; and multiple scattering corrections. Four Ph.D. dissertations and one M.S. thesis were completed during the report period. Publications consisted of three journal articles, four conference papers in proceedings, and eleven abstracts of presentations at scientific meetings. There are currently four Ph.D. and one M.S. candidates working on dissertations directly associated with the project. In addition, three other Ph.D. candidates are working on dissertations involving other aspects of neutron physics in this laboratory

  1. Neutron scattering studies in the actinide region

    This report discusses the following topics: Prompt fission neutron energy spectra for 235U and 239Pu; Two-parameter measurement of nuclear lifetimes; ''Black'' neutron detector; Data reduction techniques for neutron scattering experiments; Inelastic neutron scattering studies in 197Au; Elastic and inelastic scattering studies in 239Pu; and neutron induced defects in silicon dioxide MOS structures

  2. Neutron scattering studies in the actinide region

    During the report period we have investigated the following areas: Neutron elastic and inelastic scattering measurements on 14N, 181Ta, 232Th, 238U and 239Pu; Prompt fission spectra for 232Th, 235U, 238U and 239Pu; Theoretical studies of neutron scattering; Neutron filters; New detector systems; and Upgrading of neutron target assembly, data acquisition system, and accelerator/beam-line apparatus

  3. Actinide Speciation and Solubility in a Salt Repository (Invited)

    Reed, D.; Borkowski, M.; Richmann, M.; Lucchini, J.; Khaing, H.; Swanson, J.

    2009-12-01

    The use of bedded salt deposits for the permanent disposal of nuclear waste continues to receive much attention in the United States and internationally. This is largely based on the highly successful Waste Isolation Pilot Plant (WIPP) transuranic waste repository that was opened in 1999 in Southeastern New Mexico. A bedded salt formation, such as the one in which the WIPP is located, has many advantages that make it an ideal geology for permanent disposal of nuclear waste. This includes well established mining techniques, self-sealing that lead to a naturally-induced geologic isolation, a relatively dry environment, and a favorable chemistry. Herein we report on recent progress in our investigations, as part of ongoing recertification effort for the operating WIPP repository, to establish the redox distribution and overall solubility of actinides in brine. The overall ranking of actinides, from the perspective of potential contribution to release from the WIPP, is: Pu ~ Am >>U > Th >> Np, Cm. Our recent research emphasis has centered on the redox chemistry of multivalent actinides (e.g., U, Pu and Np) with the use of oxidation-state-invariant analogs (Th and Nd) to establish the solubilities. Under a wide range of conditions investigated, the predominant oxidation states established are Pu(III) and Pu(IV) for plutonium, U(IV) and U(VI) for uranium, and Am (III) for americium. Reduction pathways for plutonium include reaction with organics, reaction with reduced iron, and bioreduction by halophiles under anaerobic conditions. Uranium(VI) can also be reduced to U(IV) by reduced iron and microbial processes. Solubility data for neodymium (+3 analog), Uranium (+6 analog) and thorium (+4 analog) in brine are also reported. These data extend our past understanding of WIPP-specific actinide chemistry and show the WIPP, and salt-based repositories in general, to be a robust repository design from the perspective of actinide containment and immobilization.

  4. Using Correlations to Understand Changes in Actinide Bonding

    An important issue in actinide science is the changing role of the 5f electrons, both when progressing across the series, as well as how experimental variables affect these roles in a particular element's chemistries and physics. The function of these 5f electrons can be changed by experimental conditions: temperature and pressure being two of many such variables. The 5f electrons of several actinide metals, their alloys and compounds are affected greatly by pressure, due to the very large decreases in interatomic distances encountered under pressure. The latter bring about significant changes in the total energy of the system and in the electronic energy levels, which in turn affect the potential for overlap/hybridization) of their orbitals, promotion of electrons to other orbitals, etc. The physical state, temperature, pressure, specific structures, magnetic interactions and spin polarization effects are all critical parameters for bonding. Often correlations of behavior with these parameters can provide unique insights and understanding into the bonding and the changes that occur in it. With the advancement of modern computation approaches using FPMTO, or other approaches, theory has enlightened greatly the understanding of not only the bonding behavior of these elements but also the understanding of changes observed experimentally. But these computational efforts have some complications and limitations, and at times experimental findings and theory are not always in full agreement. In contrast to the behaviors of the elements, changes observed with compounds often are not be linked directly to the involvement of 5f electrons, due in part to the presence and bonding role of non-actinide atoms. The latter affect both the actinide interatomic distances and the type of electronic orbitals that interact. Presented here is an overview of the pressure behavior several actinide elements, some insights into the bonding behavior of compounds under pressure and selected

  5. Geochemistry of actinides and fission products in natural aquifer systems

    The progress in the research area of the community project MIRAGE: 'Geochemistry of actinides and fission products in natural aquatic systems' has been reviewed. This programme belongs to a specific research and technical development programme for the European Atomic Energy Community in the field of management and storage of radioactive waste. The review summarizes research progresses in subject areas: complexation with organics, colloid generation in groundwater and basic retention mechanisms in the framework of the migration of radionuclides in the geosphere. The subject areas are being investigated by 23 laboratories under interlaboratory collaborations or independent studies. (orig.)

  6. Actinides recycling assessment in a thermal reactor

    Highlights: • Actinides recycling is assessed using BWR fuel assemblies. • Four fuel rods are substituted by minor actinides rods in a UO2 and in a MOX fuel assembly. • Performance of standard fuel assemblies and the ones with the substitution is compared. • Reduction of actinides is measured for the fuel assemblies containing minor actinides rods. • Thermal reactors can be used for actinides recycling. - Abstract: Actinides recycling have the potential to reduce the geological repository burden of the high-level radioactive waste that is produced in a nuclear power reactor. The core of a standard light water reactor is composed only by fuel assemblies and there are no specific positions to allocate any actinides blanket, in this assessment it is proposed to replace several fuel rods by actinides blankets inside some of the reactor core fuel assemblies. In the first part of this study, a single uranium standard fuel assembly is modeled and the amount of actinides generated during irradiation is quantified for use it as reference. Later, in the same fuel assembly four rods containing 6 w/o of minor actinides and using depleted uranium as matrix were replaced and depletion was simulated to obtain the net reduction of minor actinides. Other calculations were performed using MOX fuel lattices instead of uranium standard fuel to find out how much reduction is possible to obtain. Results show that a reduction of minor actinides is possible using thermal reactors and a higher reduction is obtained when the minor actinides are embedded in uranium fuel assemblies instead of MOX fuel assemblies

  7. Cerium compounds in the fashion of the light actinides

    Researchers familiar with the light actinides easily recognize in cerium compounds a microcosm of the rich variety of properties seen in the light actinides. The parallelism seen between comparable cerium and actinide compounds strongly suggests that the same physical models are applicable. The most significant is the relative size of the f-orbital. Localization is generally tighter in Ce compounds than uranium compounds, making Ce roughly analogous to Np through Am. A way to see the actinide parallelism is to compare Hill plots. Compounds in the different regions of the plots (representing different physics) are isostructural compounds with the same companion (B) elements. The most common materials exhibiting a direct f-f interaction are the cubic Laves compounds. Accordingly, we have determined the band structures of CeRu2, CeRh2, CeIr2, CeOs2, and CeNi2. Compounds illustrative of the interaction of f-orbitals with ligand orbitals are the Cu3Au structured materials. Materials calculated in this class are CeRh3, CePd3, and CeSn3 - the materials of much interest as mixed valent. Although the focus is on the Ce compounds, calculations performed on uranium isomorphs are used to highlight the interesting physics

  8. Electronic structure and bulk ground state properties of the actinides

    The principal aim of this chapter is to examine in detail how the actinide elements fit into the periodic table. The actinides are neither a d transition series nor a series like the lanthanides. The electronic structure of the early part of the series finds a close conceptual parallel in a d transition series and the later part of the series is more like the lanthanides. The region of transition between the two parts of the series is of special interest and importance. Among the bulk properties of the elements there are three which are of particular importance; (a) the equilibrium volume, (b) the cohesive energy, and (c) the compressibility, or its inverse, the bulk modulus. The room temperature entropy of the actinides is discussed and its behaviour is related to the room temperature entropy of the other transition metal series. Finally, the ground state magnetism of the actinides is discussed in the context of our understanding of ground state magnetism across the periodic table. (Auth.)

  9. Review of the sorption of actinides on natural minerals

    Over the past few years, a large body of data concerning sorption of actinides on geologic media has been built in connection with high-level-waste disposal. The primary aim of the work has been to allow predictions of the migration behavior of these radionuclides in the case of a breach of the repository that allowed groundwater flow through the repository. As a result of this work, some new backfill materials specifically tailored for the actinides have also been designed. Several major mechanisms of sorption that appear to dominate the sorption of actinides have emerged from these studies. These mechanisms can be divided into solution reactions dominated by hydrolysis, chemisorption reactions, and oxidation-reduction reactions. Each of these mechanisms will be discussed in detail, with experimental examples. Surprisingly, one mechanism, cation exchange, does not play an important role; why it fails to operate in any significant way in the environmental pH region will be discussed. The implications of the sorption mechanisms for waste forms and backfill materials will be discussed in detail. These discussions will center primarily around the valence state of the actinide in various waste forms and the effect of various anions on leachability from waste forms and backfill materials

  10. Synergistic extraction of actinides : Part II. Tetra-and trivalent actinides

    A detailed discussion on the synergistic solvent extraction behaviour of tetra- and trivalent actinide ions is presented. Structural aspects of the natural donor adducts of the tetravalent actinide ion chelates involved in synergism are also discussed. (author)

  11. Spin Hamiltonians for actinide ions

    The breakdown of Russel Saunders coupling for correlated f-levels of actinide ions is due to both spin orbit coupling and the crystalline electric field (CEF). Experiments on curium, an S-state ion in the metal for which the CEF is weak indicate a g-factor close to the Russel-Saunders value. Spin-orbit coupling is therefore too weak to produce jj coupling. This suggests a model for magnetic actinide ions in which the CEF ground multiplet is well separated from higher levels, completely determining thermodynamic magnetic properties. On this basis simplified spin Hamiltonians are derived for GAMMA1-GAMMA5 ground states in order to interpret thermodynamic measurements and ordering phenomena. (author)

  12. Actinide chemistry in ionic liquids.

    Takao, Koichiro; Bell, Thomas James; Ikeda, Yasuhisa

    2013-04-01

    This Forum Article provides an overview of the reported studies on the actinide chemistry in ionic liquids (ILs) with a particular focus on several fundamental chemical aspects: (i) complex formation, (ii) electrochemistry, and (iii) extraction behavior. The majority of investigations have been dedicated to uranium, especially for the 6+ oxidation state (UO2(2+)), because the chemistry of uranium in ordinary solvents has been well investigated and uranium is the most abundant element in the actual nuclear fuel cycles. Other actinides such as thorium, neptunium, plutonium, americium, and curiumm, although less studied, are also of importance in fully understanding the nuclear fuel engineering process and the safe geological disposal of radioactive wastes. PMID:22873132

  13. Actinide recovery techniques utilizing electromechanical processes

    Under certain conditions, the separation of actinides using electromechanical techniques may be an effective means of residue processing. The separation of granular mixtures of actinides and other materials discussed in this report is based on appreciable differences in the magnetic and electrical properties of the actinide elements. In addition, the high density of actinides, particularly uranium and plutonium, may render a simultaneous separation based on mutually complementary parameters. Both high intensity magnetic separation and electrostatic separation have been investigated for the concentration of an actinide waste stream. Waste stream constituents include an actinide metal alloy and broken quartz shards. The investigation of these techniques is in support of the Integral Fast Reactor (IFR) concept currently being developed at Argonne National Laboratory under the auspices of the Department of Energy

  14. Actinide Waste Forms and Radiation Effects

    Ewing, R. C.; Weber, W. J.

    Over the past few decades, many studies of actinides in glasses and ceramics have been conducted that have contributed substantially to the increased understanding of actinide incorporation in solids and radiation effects due to actinide decay. These studies have included fundamental research on actinides in solids and applied research and development related to the immobilization of the high level wastes (HLW) from commercial nuclear power plants and processing of nuclear weapons materials, environmental restoration in the nuclear weapons complex, and the immobilization of weapons-grade plutonium as a result of disarmament activities. Thus, the immobilization of actinides has become a pressing issue for the twenty-first century (Ewing, 1999), and plutonium immobilization, in particular, has received considerable attention in the USA (Muller et al., 2002; Muller and Weber, 2001). The investigation of actinides and

  15. Anthropogenic Actinides in the Environment

    The use of nuclear energy and the testing of nuclear weapons have led to significant releases of anthropogenic isotopes, in particular a number of actinide isotopes generally not abundant in nature. Most prominent amongst these are 239Pu, 240Pu, and 236U. The study of these actinides in nature has been an active field of study ever since. Measurements of actinides are applied to nuclear safeguards, investigating the sources of contamination, and as a tracer for a number of erosion and hydrology studies. Accelerator Mass Spectrometry (AMS) is ideally suited for these studies and generally offers higher sensitivities than competing techniques, like ICP-MS or decay counting. Recent advances in AMS allow the study of “minor” plutonium isotopes (241Pu, 242Pu, and 244Pu). Furthermore, 236U can now be measured at the levels expected from the global stratospheric fall-out of the atmospheric nuclear weapon tests in the 1950s and 1960s. Even the pre-anthropogenic isotope ratios could be within reach. However, the distribution and abundance levels of these isotopes are not well known yet. I will present an overview of the field, and in detail two recent studies on minor plutonium isotopes and 236U, respectively.(author)

  16. Progress in theoretical calculation of transactinium isotope nuclear data

    Considerable progress has been made in effective use of nuclear theory for evaluation purposes. During the past few years, a number of basic improvements have developed in nuclear models commonly used for data evaluation. Actinide data evaluation can also use such improvements, but in the actinide region a further complication arises from the presence of fission competition. Nevertheless, systematic prescriptions for calculating even predicting neutron cross sections within an extended actinide region are available. Many efforts in several laboratorie are currently devoted to improving nuclear codes to be used for evaluation purposes. However at the present time numerous basic parameters associated with the neutron-induced fission process as well as neutron and gamma-ray competition have to be predetermined as input. Systematic studies of the behaviour of these parameters have been initiated with the aim of finding general trends hopefully useful for extrapolation in cases where direct information is lacking. Such trends can emerge from suitable examination of a large number of coherent experimental data, coherent theoretical results, or a combination these. This seems at the present time to be the most promising means for improving the actinide data evaluation. The aim of this paper is only to review briefly some of the main improvements either achieved or under way. The concern will be theoretical aspects useful for evaluating actinide data in the restricted incident neutron energy range from 10 KeV to 20 MeV. It is intended to focus on examples of systematics and on some improvements expected from microscopic methods under development

  17. PWRs potentialities for minor actinides burning

    In the frame of the SPIN program at CEA, the impacts of the minor actinides (MA) incineration in PWRs are analysed. The aim is to reduce the mass, the potential radiotoxicity level. The recycling of all actinide elements is evaluated in a PWR nuclear yard. A sensitivity study is done to evaluate the incineration for each minor actinide element. This gives the most efficient way of incineration for each MA elements in a PWR and helps to design a PWR burner. This burner is disposed in a PWR nuclear system in which the actinides are recycled until equilibrium. (author)

  18. Research on the chemical speciation of actinides

    A demand for the safe and effective management of spent nuclear fuel and radioactive waste generated from nuclear power plant draws increasing attention with the growth of nuclear power industry. The objective of this project is to establish the basis of research on the actinide chemistry by using highly sensitive and advanced laser-based spectroscopic systems. Researches on the chemical speciation of actinides are prerequisite for the development of technologies related to nuclear fuel cycles, especially, such as the safe management of high level radioactive wastes and the chemical examination of irradiated nuclear fuels. For supporting these technologies, laser-based spectroscopies have been applied for the chemical speciation of actinide in aqueous solutions and the quantitative analysis of actinide isotopes in spent nuclear fuels. In this report, results on the following subjects have been summarized. Development of TRLFS technology for the chemical speciation of actinides, Development of laser-induced photo-acoustic spectroscopy (LPAS) system, Application of LIBD technology to investigate dynamic behaviors of actinides dissolution reactions, Development of nanoparticle analysis technology in groundwater using LIBD, Chemical speciation of plutonium complexes by using a LWCC system, Development of LIBS technology for the quantitative analysis of actinides, Evaluation on the chemical reactions between actinides and humic substances, Spectroscopic speciation of uranium-ligand complexes in aqueous solution, Chemical speciation of actinides adsorbed on metal oxides surfaces

  19. Long-term plant availability of actinides

    Environmental releases of actinide elements raise issues about which data are very limited. Quantitative information is required to assess the long-term behavior of actinides and their potential hazards resulting from the transport through food chains leading to man. Of special interest is the effect of time on the changes in the availability of actinide elements for uptake by plants from soil. This study provides valuable information on the effects of weathering and aging on the uptake of actinides from soil by range and crop plants grown under realistic field conditions

  20. Chemistry of actinides and fission products

    This task is concerned primarily with the fundamental chemistry of the actinide and fission product elements. Special efforts are made to develop research programs in collaboration with researchers at universities and in industry who have need of national laboratory facilities. Specific areas currently under investigation include: (1) spectroscopy and photochemistry of actinides in low-temperature matrices; (2) small-angle scattering studies of hydrous actinide and fission product polymers in aqueous and nonaqueous solvents; (3) kinetic and thermodynamic studies of complexation reactions in aqueous and nonaqueous solutions; and (4) the development of inorganic ion exchange materials for actinide and lanthanide separations. Recent results from work in these areas are summarized here

  1. Systematic study of neutron induced reactions of the actinide nuclei

    Maslov, V.M. [Akadehmiya Navuk Belarusi, Minsk (Belarus). Inst. Radyyatsyjnykh Fizika-Khimichnykh Prablem; Kikuchi, Yasuyuki

    1996-06-01

    A statistical theory is used for the calculation of the neutron-induced reaction cross sections of actinide nuclides from 10 keV up to 20 MeV. Available experimental data bases for major actinides were extensively used to develop theoretical tools for consistent evaluation of neutron data of minor actinides. The approach employed up to the second chance fission threshold is based on the full-scale Hauser-Feshbach theory, a phenomenological modelling of level densities, the giant dipole resonance model for gamma-ray emission, the double-humped fission barrier model and the coupled channel optical model calculations. The pairing, collective and shell effects are introduced into the level density model for equilibrium and saddle point deformations. Step-like structures observed in fission cross section of {sup 235}U around 1 MeV incident neutron energies are interpreted as due to pairing effects. Pairing correlation parameters are adjusted to fit the fission cross section slope in the first plateau region. The level density collective effect inclusion influences drastically the extracted experimental fission barrier parameters due to the inner saddle point asymmetry. The shell effects dumping is manifested as a consistent fit of fission data above the second chance fission threshold. In case of minor actinides, fission data fits are used as a constraint for capture and inelastic scattering cross section predictions. The capture cross sections were analyzed with the allowance for (n,{gamma}n`) and (n,{gamma}f) reactions. To fit the high-energy tails in the (n,2n) reaction, the pre-equilibrium processes in the neutron channel were included. All these effects were modelled, and the model parameters were obtained using major actinides neutron data. The resulted parameter systematics were applied for analysis of available data and prediction of capture, inelastic scattering, (n,2n), (n,3n) reaction and fission cross sections. (J.P.N.). 87 refs.

  2. Modeling the Magnetic and Thermal Structure of Active Regions: 1st Year 1st Semi-Annual Progress Report

    Mikic, Zoran

    2003-01-01

    This report covers technical progress during the first six months of the first year of NASA SR&T contract "Modeling the Magnetic and Thermal Structure of Active Regions", NASW-03008, between NASA and Science Applications International Corporation, and covers the period January 14, 2003 to July 13, 2003. Under this contract SAIC has conducted research into theoretical modeling of the properties of active regions using the MHD model.

  3. Calculated Atomic Volumes of the Actinide Metals

    Skriver, H.; Andersen, O. K.; Johansson, B.

    1979-01-01

    The equilibrium atomic volume is calculated for the actinide metals. It is possible to account for the localization of the 5f electrons taking place in americium.......The equilibrium atomic volume is calculated for the actinide metals. It is possible to account for the localization of the 5f electrons taking place in americium....

  4. Environmental chemistry of the actinide elements

    The environmental chemistry of the actinide elements is a new branch of science developing with the application of nuclear energy on a larger and larger scale. Various aspects of the environmental chemistry of the actinide elements are briefly reviewed in this paper, such as its significance in the nuclear waste disposal, its coverage of research fields and possible directions for future study

  5. Improved Actinide Neutron Capture Cross Sections Using Accelerator Mass Spectrometry

    Bauder, W.; Pardo, R. C.; Kondev, F. G.; Kondrashev, S.; Nair, C.; Nusair, O.; Palchan, T.; Scott, R.; Seweryniak, D.; Vondrasek, R.; Collon, P.; Paul, M.; Youinou, G.; Salvatores, M.; Palmotti, G.; Berg, J.; Maddock, T.; Imel, G.

    2014-09-01

    The MANTRA (Measurement of Actinide Neutron TRAnsmutations) project will improve energy-integrated neutron capture cross section data across the actinide region. These data are incorporated into nuclear reactor models and are an important piece in understanding Generation IV reactor designs. We will infer the capture cross sections by measuring isotopic ratios from actinide samples, irradiated in the Advanced Test Reactor at INL, with Accelerator Mass Spectrometry (AMS) at ATLAS (ANL). The superior sensitivity of AMS allows us to extract multiple cross sections from a single sample. In order to analyze the large number of samples needed for MANTRA and to meet the goal of extracting multiple cross sections per sample, we have made a number of modifications to the AMS setup at ATLAS. In particular, we are developing a technique to inject solid material into the ECR with laser ablation. With laser ablation, we can better control material injection and potentially increase efficiency in the ECR, thus creating less contamination in the source and reducing cross talk. I will present work on the laser ablation system and preliminary results from our AMS measurements. The MANTRA (Measurement of Actinide Neutron TRAnsmutations) project will improve energy-integrated neutron capture cross section data across the actinide region. These data are incorporated into nuclear reactor models and are an important piece in understanding Generation IV reactor designs. We will infer the capture cross sections by measuring isotopic ratios from actinide samples, irradiated in the Advanced Test Reactor at INL, with Accelerator Mass Spectrometry (AMS) at ATLAS (ANL). The superior sensitivity of AMS allows us to extract multiple cross sections from a single sample. In order to analyze the large number of samples needed for MANTRA and to meet the goal of extracting multiple cross sections per sample, we have made a number of modifications to the AMS setup at ATLAS. In particular, we are

  6. PIE analysis for minor actinide

    Minor actinide (MA) is generated in nuclear fuel during the operation of power reactor. For fuel design, reactivity decrease due to it should be considered. Out of reactors, MA plays key role to define the property of spent fuel (SF) such as α-radioactivity, neutron emission rate, and criticality of SF. In order to evaluate the calculation codes and libraries for predicting the amount of MA, comparison between calculation results and experimentally obtained data has been conducted. In this report, we will present the status of PIE data of MA taken by post irradiation examinations (PIE) and several calculation results. (author)

  7. Actinide co-conversion by internal gelation

    Suitable microstructures and homogenous microspheres of actinide compounds are of interest for future nuclear fuel or transmutation target concepts to prevent the generation and dispersal of actinide powder. Sol-gel routes are being investigated as one of the possible solutions for producing these compounds. Preliminary work is described involving internal gelation to synthesize mixed compounds including minor actinides, particularly mixed actinide or mixed actinide-inert element compounds. A parameter study is discussed to highlight the importance of the initial broth composition for obtaining gel microspheres without major defects (cracks, craters, etc.). In particular, conditions are defined to produce gel beads from Zr(IV)/Y(III)/Ce(III) or Zr(IV)/An(III) systems. After gelation, the heat treatment of these microspheres is described for the purpose of better understanding the formation of cracks after calcination and verifying the effective synthesis of an oxide solid-solution. (authors)

  8. Actinides analysis by accelerator mass spectrometry

    At the ANTARES accelerator at ANSTO a new beamline has been commissioned, incorporating new magnetic and electrostatic analysers, to optimise the efficiency for Actinides detection by Accelerator Mass Spectrometry (AMS). The detection of Actinides, particularly the isotopic ratios of uranium and plutonium, provide unique signatures for nuclear safeguards purposes. We are currently engaged in a project to evaluate the application of AMS to the measurement of Actinides in environmental samples for nuclear safeguards. Levels of certain fission products, Actinides and other radioactive species can be used as indicators of undeclared nuclear facilities or activities, either on-going or in the past Other applications of ultra-sensitive detection of Actinides are also under consideration. neutron-attenuation images of a porous reservoir rock

  9. Actinide ion sensor for pyroprocess monitoring

    Jue, Jan-fong; Li, Shelly X.

    2014-06-03

    An apparatus for real-time, in-situ monitoring of actinide ion concentrations which comprises a working electrode, a reference electrode, a container, a working electrolyte, a separator, a reference electrolyte, and a voltmeter. The container holds the working electrolyte. The voltmeter is electrically connected to the working electrode and the reference electrode and measures the voltage between those electrodes. The working electrode contacts the working electrolyte. The working electrolyte comprises an actinide ion of interest. The reference electrode contacts the reference electrolyte. The reference electrolyte is separated from the working electrolyte by the separator. The separator contacts both the working electrolyte and the reference electrolyte. The separator is ionically conductive to the actinide ion of interest. The reference electrolyte comprises a known concentration of the actinide ion of interest. The separator comprises a beta double prime alumina exchanged with the actinide ion of interest.

  10. Chromosome region-specific libraries for human genome analysis. Progress report, September 1, 1991--August 31, 1992

    Kao, Fa-Ten

    1992-08-01

    During the grant period progress has been made in the successful demonstration of regional mapping of microclones derived from microdissection libraries; successful demonstration of the feasibility of converting microclones with short inserts into yeast artificial chromosome clones with very large inserts for high resolution physical mapping of the dissected region; Successful demonstration of the usefulness of region-specific microclones to isolate region-specific cDNA clones as candidate genes to facilitate search for the crucial genes underlying genetic diseases assigned to the dissected region; and the successful construction of four region-specific microdissection libraries for human chromosome 2, including 2q35-q37, 2q33-q35, 2p23-p25 and 2p2l-p23. The 2q35-q37 library has been characterized in detail. The characterization of the other three libraries is in progress. These region-specific microdissection libraries and the unique sequence microclones derived from the libraries will be valuable resources for investigators engaged in high resolution physical mapping and isolation of disease-related genes residing in these chromosomal regions.

  11. Experimental studies of actinides in molten salts

    This review stresses techniques used in studies of molten salts containing multigram amounts of actinides exhibiting intense alpha activity but little or no penetrating gamma radiation. The preponderance of studies have used halides because oxygen-containing actinide compounds (other than oxides) are generally unstable at high temperatures. Topics discussed here include special enclosures, materials problems, preparation and purification of actinide elements and compounds, and measurements of various properties of the molten volts. Property measurements discussed are phase relationships, vapor pressure, density, viscosity, absorption spectra, electromotive force, and conductance. 188 refs., 17 figs., 6 tabs

  12. Experimental studies of actinides in molten salts

    Reavis, J.G.

    1985-06-01

    This review stresses techniques used in studies of molten salts containing multigram amounts of actinides exhibiting intense alpha activity but little or no penetrating gamma radiation. The preponderance of studies have used halides because oxygen-containing actinide compounds (other than oxides) are generally unstable at high temperatures. Topics discussed here include special enclosures, materials problems, preparation and purification of actinide elements and compounds, and measurements of various properties of the molten volts. Property measurements discussed are phase relationships, vapor pressure, density, viscosity, absorption spectra, electromotive force, and conductance. 188 refs., 17 figs., 6 tabs.

  13. Spin and orbital moments in actinide compounds

    Lebech, B.; Wulff, M.; Lander, G.H.

    1991-01-01

    -electron band-structure calculations, is that the orbital moments of the actinide 5f electrons are considerably reduced from the values anticipated by a simple application of Hund's rules. To test these ideas, and thus to obtain a measure of the hybridization, we have performed a series of neutron scattering...... experiments designed to determine the magnetic moments at the actinide and transition-metal sublattice sites in compounds such as UFe2, NpCo2, and PuFe2 and to separate the spin and orbital components at the actinide sites. The results show, indeed, that the ratio of the orbital to spin moment is reduced as...

  14. Actinide chemistry in the far field

    The environmental chemistry of the actinides is complicated due both to the extensive redox and coordination chemistry of the elements and also to the complexity of the reactive phases encountered in natural environments. In the far field, interactions with reactive surfaces, coatings and colloidal particles will play a crucial role in controlling actinide mobility. By virtue of both their abundance and reactivity; clays and other layer aluminosilicate minerals, hydrous oxides and organic matter (humic substances) are all identified as having the potential to react with actinide ions and some possible modes of interaction are described, together with experimental evidence for their occurrence. (author)

  15. Electronic structure and magnetic properties of actinides

    The study of the actinide series shows the change between transition metal behavior and lanthanide behavior, between constant weak paramagnetism for thorium and strong Curie-Weiss paramagnetism for curium. Curium is shown to be the first metal of the actinide series to be magnetically ordered, its Neel temperature being 52K. The magnetic properties of the actinides depending on all the peripheral electrons, their electronic structure was studied and an attempt was made to determine it by means of a phenomenological model. Attempts were also made to interrelate the different physical properties which depend on the outer electronic structure

  16. Endohedral Fullerenes with Actinide-Actinide Bonds: Unwilling Bonding in U2@C80

    Foroutan-Nejad, C.; Patzschke, M.; Straka, Michal

    Opole: -, 2014. [MMNB 2014. Polish-Taiwanese Conference. From Molecular Modeling to Nano- and Biotechnology . 04.09.2014-06.09.2014, Opole] R&D Projects: GA ČR(CZ) GA14-03564S Grant ostatní: European Social Fund(XE) CZ.1.07/2.3.00/30.009 Institutional support: RVO:61388963 Keywords : endohedral actinide fullerene * U-U bonding * actinide-actinide bonding Subject RIV: CF - Physical ; Theoretical Chemistry

  17. PF-4 actinide disposition strategy

    The dwindling amount of Security Category I processing and storage space across the DOE Complex has driven the need for more effective storage of nuclear materials at LANL's Plutonium Facility's (PF-4's) vault. An effort was begun in 2009 to create a strategy, a roadmap, to identify all accountable nuclear material and determine their disposition paths, the PF-4 Actinide Disposition Strategy (PADS). Approximately seventy bins of nuclear materials with similar characteristics - in terms of isotope, chemical form, impurities, disposition location, etc. - were established in a database. The ultimate disposition paths include the material to remain at LANL, disposition to other DOE sites, and disposition to waste. If all the actions described in the document were taken, over half of the containers currently in the PF-4 vault would been eliminated. The actual amount of projected vault space will depend on budget and competing mission requirements, however, clearly a significant portion of the current LANL inventory can be either dispositioned or consolidated.

  18. Subsurface interactions of actinide species and microorganisms. Implications for the bioremediation of actinide-organic mixtures

    By reviewing how microorganisms interact with actinides in subsurface environments, the way how bioremediation controls the fate of actinides is assessed. Actinides often are co-contaminants with strong organic chelators, chlorinated solvents, and fuel hydrocarbons. Bioremediation can immobilize the actinides, biodegrade the co-contaminants, or both. Actinides at the IV oxidation state are the least soluble, and microorganisms accelerate precipitation by altering the actinide's oxidation state or its speciation. The way how microorganisms directly oxidize or reduce actinides and how microbiological reactions that biodegrade strong organic chelators, alter the pH, and consume or produce precipitating anions strongly affect actinide speciation and, therefore, mobility is described. Why inhibition caused by chemical or radiolytic toxicities uniquely affects microbial reactions is explained. Due to the complex interactions of the microbiological and chemical phenomena, mathematical modeling is an essential tool for research on and application of bioremediation involving co-contamination with actinides. Development of mathematical models that link microbiological and geochemical reactions is described. Throughout, the key research needs are identified. (author)

  19. Subsurface interactions of actinide species and microorganisms : implications for the bioremediation of actinide-organic mixtures.

    Banaszak, J.E.; Reed, D.T.; Rittmann, B.E.

    1999-02-12

    By reviewing how microorganisms interact with actinides in subsurface environments, we assess how bioremediation controls the fate of actinides. Actinides often are co-contaminants with strong organic chelators, chlorinated solvents, and fuel hydrocarbons. Bioremediation can immobilize the actinides, biodegrade the co-contaminants, or both. Actinides at the IV oxidation state are the least soluble, and microorganisms accelerate precipitation by altering the actinide's oxidation state or its speciation. We describe how microorganisms directly oxidize or reduce actinides and how microbiological reactions that biodegrade strong organic chelators, alter the pH, and consume or produce precipitating anions strongly affect actinide speciation and, therefore, mobility. We explain why inhibition caused by chemical or radiolytic toxicities uniquely affects microbial reactions. Due to the complex interactions of the microbiological and chemical phenomena, mathematical modeling is an essential tool for research on and application of bioremediation involving co-contamination with actinides. We describe the development of mathematical models that link microbiological and geochemical reactions. Throughout, we identify the key research needs.

  20. Subsurface interactions of actinide species and microorganisms : implications for the bioremediation of actinide-organic mixtures

    By reviewing how microorganisms interact with actinides in subsurface environments, we assess how bioremediation controls the fate of actinides. Actinides often are co-contaminants with strong organic chelators, chlorinated solvents, and fuel hydrocarbons. Bioremediation can immobilize the actinides, biodegrade the co-contaminants, or both. Actinides at the IV oxidation state are the least soluble, and microorganisms accelerate precipitation by altering the actinide's oxidation state or its speciation. We describe how microorganisms directly oxidize or reduce actinides and how microbiological reactions that biodegrade strong organic chelators, alter the pH, and consume or produce precipitating anions strongly affect actinide speciation and, therefore, mobility. We explain why inhibition caused by chemical or radiolytic toxicities uniquely affects microbial reactions. Due to the complex interactions of the microbiological and chemical phenomena, mathematical modeling is an essential tool for research on and application of bioremediation involving co-contamination with actinides. We describe the development of mathematical models that link microbiological and geochemical reactions. Throughout, we identify the key research needs

  1. Structural and functional hallmarks of amyotrophic lateral sclerosis progression in motor- and memory-related brain regions

    Christian Michael Stoppel; Stefan Vielhaber; Cindy Eckart; Judith Machts; Jörn Kaufmann; Hans-Jochen Heinze; Katja Kollewe; Susanne Petri; Reinhard Dengler; Jens-Max Hopf; Mircea Ariel Schoenfeld

    2014-01-01

    Previous studies have shown that in amyotrophic lateral sclerosis (ALS) multiple motor and extra-motor regions display structural and functional alterations. However, their temporal dynamics during disease-progression are unknown. To address this question we employed a longitudinal design assessing motor- and novelty-related brain activity in two fMRI sessions separated by a 3-month interval. In each session, patients and controls executed a Go/NoGo-task, in which additional presentation of n...

  2. Overview of actinide chemistry in the WIPP

    Borkowski, Marian [Los Alamos National Laboratory; Lucchini, Jean - Francois [Los Alamos National Laboratory; Richmann, Michael K [Los Alamos National Laboratory; Reed, Donald T [Los Alamos National Laboratory; Khaing, Hnin [Los Alamos National Laboratory; Swanson, Juliet [Los Alamos National Laboratory

    2009-01-01

    The year 2009 celebrates 10 years of safe operations at the Waste Isolation Pilot Plant (WIPP), the only nuclear waste repository designated to dispose defense-related transuranic (TRU) waste in the United States. Many elements contributed to the success of this one-of-the-kind facility. One of the most important of these is the chemistry of the actinides under WIPP repository conditions. A reliable understanding of the potential release of actinides from the site to the accessible environment is important to the WIPP performance assessment (PA). The environmental chemistry of the major actinides disposed at the WIPP continues to be investigated as part of the ongoing recertification efforts of the WIPP project. This presentation provides an overview of the actinide chemistry for the WIPP repository conditions. The WIPP is a salt-based repository; therefore, the inflow of brine into the repository is minimized, due to the natural tendency of excavated salt to re-seal. Reducing anoxic conditions are expected in WIPP because of microbial activity and metal corrosion processes that consume the oxygen initially present. Should brine be introduced through an intrusion scenario, these same processes will re-establish reducing conditions. In the case of an intrusion scenario involving brine, the solubilization of actinides in brine is considered as a potential source of release to the accessible environment. The following key factors establish the concentrations of dissolved actinides under subsurface conditions: (1) Redox chemistry - The solubility of reduced actinides (III and IV oxidation states) is known to be significantly lower than the oxidized forms (V and/or VI oxidation states). In this context, the reducing conditions in the WIPP and the strong coupling of the chemistry for reduced metals and microbiological processes with actinides are important. (2) Complexation - For the anoxic, reducing and mildly basic brine systems in the WIPP, the most important

  3. PWRs potentialities for minor actinides burning

    In the frame of the SPIN program at CEA, the impacts of the Minor Actinides (MA) incineration in PWRs are analysed. The aim is to reduce the mass and the potential radiotoxicity level. This study is done separately one on the Plutonium recycling. But the plutonium is essential. Thus, the recycling of all Actinide elements is evaluated in a PWR nuclear yard. A sensitivity study is done to evaluate the incineration for each Minor Actinide element. This gives us the most efficient way of incineration for each MA element in a PWR and help us to design a PWR burner. This burner is disposed in a PWR nuclear system in which the Actinides are recycled until equilibrium. (authors). 2 refs

  4. Electronic structure and correlation effects in actinides

    Albers, R.C.

    1998-12-01

    This report consists of the vugraphs given at a conference on electronic structure. Topics discussed are electronic structure, f-bonding, crystal structure, and crystal structure stability of the actinides and how they are inter-related.

  5. Preparation of actinide targets by electrodeposition

    Trautmann, N.; Folger, H.

    1989-10-01

    Actinide targets with varying thicknesses on different substrates have been prepared by electrodeposition either from aqueous solutions or from solutions of their nitrates in isopropyl alcohol. With these techniques the actinides can be deposited almost quantitatively on various backing materials within 15 to 30 min. Targets of thorium, uranium, neptunium, plutonium, americium, curium and californium with areal densities from almost carrier-free up to 1.4 mg/cm 2 on thin beryllium, carbon, titanium, tantalum and platinum foils have been prepared. In most cases, prior to the deposition, the actinides had to be purified chemically and for some of them, due to the limited amount of material available, recycling procedures were required. Applications of actinide targets in heavy-ion reactions are briefly discussed.

  6. Actinide research to solve some practical problems

    The following topics are discussed: generation of plutonium inventories by nuclear power plants; resettlement of the Marshallese Islanders into an actinide contaminated environment; high radiation background areas of the world; and radiation hazards to uranium miners

  7. Advanced Aqueous Separation Systems for Actinide Partitioning

    Nash, Kenneth L.; Clark, Sue; Meier, G Patrick; Alexandratos, Spiro; Paine, Robert; Hancock, Robert; Ensor, Dale

    2012-03-21

    One of the most challenging aspects of advanced processing of spent nuclear fuel is the need to isolate transuranium elements from fission product lanthanides. This project expanded the scope of earlier investigations of americium (Am) partitioning from the lanthanides with the synthesis of new separations materials and a centralized focus on radiochemical characterization of the separation systems that could be developed based on these new materials. The primary objective of this program was to explore alternative materials for actinide separations and to link the design of new reagents for actinide separations to characterizations based on actinide chemistry. In the predominant trivalent oxidation state, the chemistry of lanthanides overlaps substantially with that of the trivalent actinides and their mutual separation is quite challenging.

  8. BWR Assembly Optimization for Minor Actinide Recycling

    G. Ivan Maldonado; John M. Christenson; J.P. Renier; T.F. Marcille; J. Casal

    2010-03-22

    The Primary objective of the proposed project is to apply and extend the latest advancements in LWR fuel management optimization to the design of advanced boiling water reactor (BWR) fuel assemblies specifically for the recycling of minor actinides (MAs).

  9. Superconductivity in rare earth and actinide compounds

    Rare earth and actinide compounds and the extraordinary superconducting and magnetic phenomena they exhibit are surveyed. The rare earth and actinide compounds described belong to three classes of novel superconducting materials: high temperature, high field superconductors (intermetallics and layered cuprates); superconductors containing localized magnetic moments; heavy fermion superconductors. Recent experiments on the resistive upper critical field of high Tc cuprate superconductors and the peak effect in the critical current density of the f-electron superconductor CeRu2 are discussed. (orig.)

  10. Lanthanides and actinides in ionic liquids

    Binnemans, Koen

    2007-01-01

    This lecture gives an overview of the research possibilities offered by combining f-elements (lanthanides and actinides) with ionic liquids [1] Many ionic liquids are solvents with weakly coordinating anions. Solvation of lanthanide and actinide ions in these solvents is different from what is observed in conventional organic solvents and water. The poorly solvating behavior can also lead to the formation of coordination compounds with low coordination numbers. The solvation of f-elements can...

  11. New molecules to separate actinides: the picolinamides

    The reprocessing of spent fuel is made with the Purex process, funded on liquid-liquid extraction of uranium nitrates(VI) and plutonium nitrates(IV) by the BTP (tributyl phosphate). To improve this proceeding, we look for extractants which allow, beyond U and Pu extractions, these of actinides (II) and allow separation of the whole actinides from the fission products, which have an important fraction of lanthanides. A new family seems to give good results: the picolinamides

  12. Evaluation of actinide partitioning and transmutation

    After a few centuries of radioactive decay the long-lived actinides, the elements of atomic numbers 89-103, may constitute the main potential radiological health hazard in nuclear wastes. This is because all but a very few fission products (principally technetium-99 and iodine-129) have by then undergone radioactive decay to insignificant levels, leaving the actinides as the principal radionuclides remaining. It was therefore at first sight an attractive concept to recycle the actinides to nuclear reactors, so as to eliminate them by nuclear fission. Thus, investigations of the feasibility and potential benefits and hazards of the concept of 'actinide partitioning and transmutation' were started in numerous countries in the mid-1970s. This final report summarizes the results and conclusions of technical studies performed in connection with a four-year IAEA Co-ordinated Research Programme, started in 1976, on the ''Environmental Evaluation and Hazard Assessment of the Separation of Actinides from Nuclear Wastes followed by either Transmutation or Separate Disposal''. Although many related studies are still continuing, e.g. on waste disposal, long-term safety assessments, and waste actinide management (particularly for low and intermediate-level wastes), some firm conclusions on the overall concept were drawn by the programme participants, which are reflected in this report

  13. Policy Paper 26: The Middle East Arms Control and Regional Security Talks: Progress, Problems, and Prospects

    Jentleson, Bruce

    1996-01-01

    The record of the Arms Control and Regional Security (ACRS) Working Group thus far is a mixed one. On the one hand, the very creation of a multilateral process for arms control and regional security in a region where no comparable process ever before existed is in itself a significant achievement. A working agenda then was defined, and by late 1994 a series of initial multilateral agreements had been negotiated for confidence-building measures (CBMs), confidence-and-security-building measures...

  14. A sub-national hunger index for Ethiopia: Assessing progress in region-level outcomes

    Schmidt, Emily; Dorosh, Paul A.

    2009-01-01

    Access to sufficient food and nutrients is essential for household welfare, as well as for accomplishing other development objectives. Households with insufficient access to food often face other challenges related to food insecurity including poor health and declines in productivity. In order to better target food aid assistance, evaluate progress, and design efficient intervention strategies, a transparent and reliable database on food insecurity is necessary. With the goal of providing a m...

  15. Region of interest and windowing-based progressive medical image delivery using JPEG2000

    Nagaraj, Nithin; Mukhopadhyay, Sudipta; Wheeler, Frederick W.; Avila, Ricardo S.

    2003-05-01

    An important telemedicine application is the perusal of CT scans (digital format) from a central server housed in a healthcare enterprise across a bandwidth constrained network by radiologists situated at remote locations for medical diagnostic purposes. It is generally expected that a viewing station respond to an image request by displaying the image within 1-2 seconds. Owing to limited bandwidth, it may not be possible to deliver the complete image in such a short period of time with traditional techniques. In this paper, we investigate progressive image delivery solutions by using JPEG 2000. An estimate of the time taken in different network bandwidths is performed to compare their relative merits. We further make use of the fact that most medical images are 12-16 bits, but would ultimately be converted to an 8-bit image via windowing for display on the monitor. We propose a windowing progressive RoI technique to exploit this and investigate JPEG 2000 RoI based compression after applying a favorite or a default window setting on the original image. Subsequent requests for different RoIs and window settings would then be processed at the server. For the windowing progressive RoI mode, we report a 50% reduction in transmission time.

  16. Actinide transmutation in nuclear reactors

    An optimization method is developed to maximize the burning capability of the ALMR while complying with all constraints imposed on the design for reliability and safety. This method leads to a maximal transuranics enrichment, which is being limited by constraints on reactivity. The enrichment can be raised by using the neutrons less efficiently by increasing leakage from the fuel. With the developed optimization method, a metallic and an oxide fueled ALMR were optimized. Both reactors perform equally well considering the burning of transuranics. However, metallic fuel has a much higher heat conductivity coefficient, which in general leads to better safety characteristics. In search of a more effective waste transmuter, a modified Molten Salt Reactor was designed. A MSR operates on a liquid fuel salt which makes continuous refueling possible, eliminating the issue of the burnup reactivity loss. Also, a prompt negative reactivity feedback is possible for an overmoderated reactor design, even when the Doppler coefficient is positive, due to the fuel expansion with fuel temperature increase. Furthermore, the molten salt fuel can be reprocessed based on a reduction process which is not sensitive to the short-lived spontaneously fissioning actinides. (orig./HP)

  17. Gas core reactors for actinide transmutation and breeder applications. Annual report

    This work consists of design power plant studies for four types of reactor systems: uranium plasma core breeder, uranium plasma core actinide transmuter, UF6 breeder and UF6 actinide transmuter. The plasma core systems can be coupled to MHD generators to obtain high efficiency electrical power generation. A 1074 MWt UF6 breeder reactor was designed with a breeding ratio of 1.002 to guard against diversion of fuel. Using molten salt technology and a superheated steam cycle, an efficiency of 39.2% was obtained for the plant and the U233 inventory in the core and heat exchangers was limited to 105 Kg. It was found that the UF6 reactor can produce high fluxes (10 to the 14th power n/sq cm-sec) necessary for efficient burnup of actinide. However, the buildup of fissile isotopes posed severe heat transfer problems. Therefore, the flux in the actinide region must be decreased with time. Consequently, only beginning-of-life conditions were considered for the power plant design. A 577 MWt UF6 actinide transmutation reactor power plant was designed to operate with 39.3% efficiency and 102 Kg of U233 in the core and heat exchanger for beginning-of-life conditions

  18. Experimental level-structure determination in odd-odd actinide nuclei

    The status of experimental determination of level structure in odd-odd actinide nuclei is reviewed. A technique for modeling quasiparticle excitation energies and rotational parameters in odd-odd deformed nuclei is applied to actinide species where new experimental data have been obtained by use of neutron-capture gamma-ray spectroscopy. The input parameters required for the calculation are derived from empirical data on single-particle excitations in neighboring odd-mass nuclei. Calculated configuration-specific values for the Gallagher-Moszkowski splittings are used. Calculated and experimental level structures for 238Np, 244Am, and 250Bk are compared, as well as those for several nuclei in the rare-earth region. The agreement for the actinide species is excellent, with bandhead energies deviating 22 keV and rotational parameters 5%, on the average. Applications of this modeling technique are discussed

  19. Waste disposal aspects of actinide separation

    Two recent NRPB reports are summarized (Camplin, W.C., Grimwood, P.D. and White, I.F., The effects of actinide separation on the radiological consequences of disposal of high-level radioactive waste on the ocean bed, Harwell, National Radiological Protection Board, NRPB-R94 (1980), London, HMSO; Hill, M.D., White, I.F. and Fleishman, A.B., The effects of actinide separation on the radiological consequences of geologic disposal of high-level waste. Harwell, National Radiological Protection Board, NRPB-R95 (1980), London, HMSO). They describe preliminary environmental assessments relevant to waste arising from the reprocessing of PWR fuel. Details are given of the modelling of transport of radionuclides to man, and of the methodology for calculating effective dose equivalents in man. Emphasis has been placed on the interaction between actinide separation and the disposal options rather than comparison of disposal options. The reports show that the effects of actinide separation do depend on the disposal method. Conditions are outlined where the required substantial further research and development work on actinide separation and recycle would be justified. Toxicity indices or 'toxic potentials' can be misleading and should not be used to guide research and development. (U.K.)

  20. Solubility of actinide surrogates in nuclear glasses

    This paper discusses the results of a study of actinide surrogates in a nuclear borosilicate glass to understand the effect of processing conditions (temperature and oxidizing versus reducing conditions) on the solubility limits of these elements. The incorporation of cerium oxide, hafnium oxide, and neodymium oxide in this borosilicate glass was investigated. Cerium is a possible surrogate for tetravalent and trivalent actinides, hafnium for tetravalent actinides, and neodymium for trivalent actinides. The material homogeneity was studied by optical, scanning electron microscopy. Cerium LIII XANES spectroscopy showed that the Ce3+/Cetotal ratio increased from about 0.5 to 0.9 as the processing temperature increased from 1100 to 1400 deg. C. Cerium LIII XANES spectroscopy also confirmed that the increased Ce solubility in glasses melted under reducing conditions was due to complete reduction of all the cerium in the glass. The most significant results pointed out in the current study are that the solubility limits of the actinide surrogates increases with the processing temperature and that Ce3+ is shown to be more soluble than Ce4+ in this borosilicate glass

  1. TUCS/phosphate mineralization of actinides

    Nash, K.L. [Argonne National Lab., IL (United States)

    1997-10-01

    This program has as its objective the development of a new technology that combines cation exchange and mineralization to reduce the concentration of heavy metals (in particular actinides) in groundwaters. The treatment regimen must be compatible with the groundwater and soil, potentially using groundwater/soil components to aid in the immobilization process. The delivery system (probably a water-soluble chelating agent) should first concentrate the radionuclides then release the precipitating anion, which forms thermodynamically stable mineral phases, either with the target metal ions alone or in combination with matrix cations. This approach should generate thermodynamically stable mineral phases resistant to weathering. The chelating agent should decompose spontaneously with time, release the mineralizing agent, and leave a residue that does not interfere with mineral formation. For the actinides, the ideal compound probably will release phosphate, as actinide phosphate mineral phases are among the least soluble species for these metals. The most promising means of delivering the precipitant would be to use a water-soluble, hydrolytically unstable complexant that functions in the initial stages as a cation exchanger to concentrate the metal ions. As it decomposes, the chelating agent releases phosphate to foster formation of crystalline mineral phases. Because it involves only the application of inexpensive reagents, the method of phosphate mineralization promises to be an economical alternative for in situ immobilization of radionuclides (actinides in particular). The method relies on the inherent (thermodynamic) stability of actinide mineral phases.

  2. New reagents for actinide-lanthanide group separations

    Organic extractants which possess nitrogen or sulfur donor atoms preferentially complex the trivalent actinide. They are potential reagents for actinide lanthanide group separations, which can be performed at low pH without the addition of inorganic salts

  3. Environmental restoration in regions of uranium mining and milling in Ukraine: Progress, problems and perspectives

    Uranium exploration activities in Ukraine were initiated in 1946. So far 21 uranium reserves have been identified in the Southern regions of Ukraine. Industrial scale mining has been undertaken in two main areas -ZhovtiVody (Dnipropetrovsk region) and more recently - near the city of Kirovograd. Uranium milling capabilities were created in ZhovtiVody and Dniprodzerzhinsk. At Dniprodzerzhinsk Prydniprovsky Chemical Plant uranium milling started in the late 40's, initially using ores from the countries of Central Europe. Lack of relevant environmental standards and appropriate technologies for uranium extraction contributed to contamination of both industrial and residential areas. As a result, about 1340 ha of industrial areas were contaminated and ecologically affected. Extensive utilization of waste rock pile for road and building construction in the 50's and 60's resulted in contamination of residential areas in the region. To provide a comprehensive solution to the radioecological problems of the ZhovtiVody area a State Programme of Actions up to the year 2005 was adopted by the Ukrainian government in 1995. A timely methodological and information support for national activities on environmental restoration in Ukraine was provided by IAEA regional project RER/9/022. In April 1996 under the framework of the RER/9/022 project, seminar on environmental restoration in regions of uranium mining and milling took place in the town of Zhovti Vody, that allowed involvement of local experts and organizations into the project activities directly. The proposed paper is based on the vast amount of data accumulated in Ukraine during RER/9/022 covering the period 1993-1996. Severe lack of finance adversely affected all activities within the nuclear sector, environmental restoration implementation being the most affected. In such circumstances RER/9/022 remained as one of the most valuable contributing factors in the development of regulations, guidance and practices in the

  4. Separation of actinides with alkylpyridinium salts

    Various f-elements are separated as anionic complexes from both acidic and alkaline solutions by precipitation with alkylpyridinium salts. The precipitates are also cationic surfactants where the simple counter-ion (e.g. nitrate or chloride) is replaced by the negatively charged complex anion of an actinide or lanthanide. The low solubility of these precipitates is explained by a strong affinity of divalent complex counter-ions of f-elements to the quaternary nitrogen. Precipitations in solutions of nitric acid allow to separate tetravalent f-elements from other metals, in alkaline carbonate solutions tetravalent and hexavalent actinides are precipitated simultaneously. The last procedure yields precipitates, which are very intimate mixtures of hexavalent and tetravalent actinides. This allows to prepare mixed oxides in a simple way. (author) 6 refs.; 3 figs.; 3 tabs

  5. Minior Actinide Doppler Coefficient Measurement Assessment

    Nolan E. Hertel; Dwayne Blaylock

    2008-04-10

    The "Minor Actinide Doppler Coefficient Measurement Assessment" was a Department of Energy (DOE) U-NERI funded project intended to assess the viability of using either the FLATTOP or the COMET critical assembly to measure high temperature Doppler coefficients. The goal of the project was to calculate using the MCNP5 code the gram amounts of Np-237, Pu-238, Pu-239, Pu-241, AM-241, AM-242m, Am-243, and CM-244 needed to produce a 1E-5 in reactivity for a change in operating temperature 800C to 1000C. After determining the viability of using the assemblies and calculating the amounts of each actinide an experiment will be designed to verify the calculated results. The calculations and any doncuted experiments are designed to support the Advanced Fuel Cycle Initiative in conducting safety analysis of advanced fast reactor or acceoerator-driven transmutation systems with fuel containing high minor actinide content.

  6. Research on Actinides in Nuclear Fuel Cycles

    The electrochemical/spectroscopic integrated measurement system was designed and set up for spectro-electrochemical measurements of lanthanide and actinide ions in high temperature molten salt media. A compact electrochemical cell and electrode system was also developed for the minimization of reactants, and consequently minimization of radioactive waste generation. By applying these equipment, oxidation and reduction behavior of lanthanide and actinide ions in molten salt media have been made. Also, thermodynamic parameter values are determined by interpreting the results obtained from electrochemical measurements. Several lanthanide ions exhibited fluorescence properties in molten salt. Also, UV-VIS measurement provided the detailed information regarding the oxidation states of lanthanide and actinide ions in high temperature molten salt media

  7. Neutron scattering studies of the actinides

    The electronic structure of actinide materials presents a unique example of the interplay between localized and band electrons. Together with a variety of other techniques, especially magnetization and the Mossbauer effect, neutron studies have helped us to understand the systematics of many actinide compounds that order magnetically. A direct consequence of the localization of 5f electrons is the spin-orbit coupling and subsequent spin-lattice interaction that often leads to strongly anisotropic behavior. The unusual phase transition in UO2, for example, arises from interactions between quadrupole moments. On the other hand, in the monopnictides and monochalcogenides, the anisotropy is more difficult to understand, but probably involves an interaction between actinide and anion wave functions. A variety of neutron experiments, including form-factor studies, critical scattering and measurements of the elementary excitations have now been performed, and the conceptual picture emerging from these studies will be discussed

  8. Coordination chemistry for new actinide separation processes

    The amount of wastes and the number of chemical steps can be decreased by replacing the PUREX process extractant (TBP) by, N.N- dialkylamides (RCONR'2). Large amounts of deep underground storable wastes can be stored into sub-surface disposals if the long lived actinide isotopes are removed. Spent nuclear fuels reprocessing including the partitioning of the minor actinides Np, Am, Cm and their transmutation into short half lives fission products is appealing to the public who is not favorable to the deep underground storage of large amounts of long half lived actinide isotopes. In this paper coordination chemistry problems related to improved chemical separations by solvent extraction are presented. 2 tabs.; 4 refs

  9. PROGRESS ON THE INTERACTION REGION DESIGN AND DETECTOR INTEGRATION AT JLAB'S MEIC

    Morozov, Vasiliy; Brindza, Paul; Camsonne, Alexandre; Derbenev, Yaroslav; Ent, Rolf; Gaskell, David; Lin, Fanglei; Nadel-Turonski, Pawel; Ungaro, Maurizio; Zhang, Yuhong; Hyde, Charles; Park, Kijun; Sullivan, Michael; Zhao, Zhiwen

    2014-07-01

    One of the unique features of JLab's Medium-energy Electron-Ion Collider (MEIC) is a full-acceptance detector with a dedicated, small-angle, high-resolution detection system, capable of covering a wide range of momenta (and charge-to-mass ratios) with respect to the original ion beam to enable access to new physics. We present an interaction region design developed with close integration of the detection and beam dynamical aspects. The dynamical aspect of the design rests on a symmetry-based concept for compensation of non-linear effects. The optics and geometry have been optimized to accommodate the detection requirements and to ensure the interaction region's modularity for ease of integration into the collider ring lattices. As a result, the design offers an excellent detector performance combined with the necessary provisions for non-linear dynamical optimization.

  10. LSE centre for economic performance: urban renewal and regional growth: muddled objectives and mixed progress

    Overman, Henry G.

    2010-01-01

    A new series of Election Analyses is now available from the LSE’s Centre for Economic Performance (CEP). The series will discuss the research evidence on some of the key policy battlegrounds of the 2010 General Election, including macroeconomic policy, immigration, health, education, crime, poverty and inequality, labour market policy, regional policy, energy and the environment, financial regulation and bankers’ bonuses, and foreign aid. Since 1997, the Labour government has spent c...

  11. Progress and review of brachytherapy for cancer of the oral region

    Radiation therapy contributes greatly to the treatment of head and neck cancer, because it maintains the normal anatomy, minimizes functional loss, and facilitates a patient's return to work. Brachytherapy using small radiation sources is an indispensable modality for the treatment of cancer of the oral region, in which emphasis should be laid on the maintenance of normal anatomy and function and a high quality of life. Brachytherapy was performed in 62% of the radiation therapy patients with cancer of the oral region. Interstitial brachytherapy with radium, 192Ir-hairpin was administered to more than 80% of the patients with tongue cancer and 198Au-grain was frequently used for other site of the oral region. Introduction of the remote afterloading system (RALS) has completely eliminated the possibility of personnel exposure and increased the indication for brachytherapy. There is a lot of work to be done in the near future, including the establishment of dose-time relationship for RALS and the development of related apparatus and instruments and the standardization of dose assessment. (author)

  12. Some new progress in scientific research on the Lop Nur Lake region, Xinjiang, China

    夏训诚; 穆桂金; 雷加强

    2002-01-01

    The Lop Nur Lake, a famous lake in the arid areas of China, is located in the communi-cations center of the ancient Silk Road which facilitated the flow of culture between China andWestern countries and enjoyed the great reputation in the ancient history of China. Since the re-cent 100 years, some Chinese and foreign scholars have explored and investigated here, they,however, could not get to the hinterland of the lake basin due to the hard and dangerous roads.Therefore, there are many divergences and controversies about the Lop Nur Lake region[1'2]. Inorder to clarify these issues, know the usable natural resources and sum up the historical experi-ences and lessons of dry-up of the Lop Nur Lake, a scientific investigation team was organized byXinjiang Branch of the Chinese Academy of Sciences to carry out the investigation and researchabout the Lop Nur Lake region in the 1980s. Recently, some personnel from CCTV and other in-stitutions went to the lower reaches of the Tarim River and the Lop Nur Lake region to undertakethe research for coordinating the strategic decision of the Great Development of Western Chinaand the synthetic harnessing of the Tarim River, and a series of achievements in scientific researchhave been achieved.

  13. Spin-Orbit Coupling in Actinide Cations

    Bagus, Paul S.; Ilton, Eugene S.; Martin, Richard L.; Jensen, Hans Jorgen A.; Knecht, Stefan

    2012-09-01

    The limiting case of Russell-Saunders coupling, which leads to a maximum spin alignment for the open shell electrons, usually explains the properties of high spin ionic crystals with transition metals. For actinide compounds, the spin-orbit splitting is large enough to cause a significantly reduced spin alignment. Novel concepts are used to explain the dependence of the spin alignment on the 5f shell occupation. We present evidence that the XPS of ionic actinide materials may provide direct information about the angular momentum coupling within the 5f shell.

  14. Spin-orbit coupling in actinide cations

    Bagus, Paul S.; Ilton, Eugene S.; Martin, Richard L.; Jensen, Hans Jørgen Aa.; Knecht, Stefan

    2012-09-01

    The limiting case of Russell-Saunders coupling, which leads to a maximum spin alignment for the open shell electrons, usually explains the properties of high spin ionic crystals with transition metals. For actinide compounds, the spin-orbit splitting is large enough to cause a significantly reduced spin alignment. Novel concepts are used to explain the dependence of the spin alignment on the 5f shell occupation. We present evidence that the XPS of ionic actinide materials may provide direct information about the angular momentum coupling within the 5f shell.

  15. Actinide phosphonate complexes in aqueous solutions

    Complexes formed by actinides with carboxylic acids, polycarboxylic acids, and aminopolycarboxylic acids play a central role in both the basic and process chemistry of the actinides. Recent studies of f-element complexes with phosphonic acid ligands indicate that new ligands incorporating doubly ionizable phosphonate groups (-PO3H2) have many properties which are unique chemically, and promise more efficient separation processes for waste cleanup and environmental restoration. Simple diphosphonate ligands form much stronger complexes than isostructural carboxylates, often exhibiting higher solubility as well. In this manuscript recent studies of the thermodynamics and kinetics of f-element complexation by 1,1 and 1,2 diphosphonic acid ligands are described

  16. Sequential analysis of selected actinides in urine

    The monitoring of personnel by urinalysis for suspected contamination by actinides necessitated the development and implementation of an analytical scheme that will separate and identify alpha emitting radionuclides of these elements. The present work deals with Pu, Am, and Th. These elements are separated from an ashed urine sample by means of coprecipitation and ion exchange techniques. The final analysis is carried out by electroplating the actinides and counting in a α-spectrometer. Mean recoveries of these elements from urine are: Pu 64%, Am 74% and Th 69%. (auth)

  17. Uncertainties in exposures, contamination level and doses after inhalation of actinides

    In France, after occupational exposure to radioactive aerosols, committed doses are currently calculated by an ascending approach from biological data to estimate the initial contamination using dose per unit intake (DPUI). Specific DPUI can be calculated depending on the contamination. This paper is an overview on uncertainties in exposure level, biokinetics of radionuclides and doses after inhalation exposure to aerosol containing actinides. Data reported in the literature and those obtained in studies which are still in progress are described. A comparison of the uncertainties has been done after an ascending and a descending approach. In this later case, aerosol deposition within the respiratory tract is estimated from air sampling at the work place (estimate of the activity of the aerosol). The largest uncertainties were calculated after a descending application of the models. The results here reported pointed out the need of the knowledge of the uncertainties for a realistic interpretation of the results obtained after dose calculation, as well as the application limits of some ICRP models. Moreover, difficulties to estimate risk of cancer from doses are pointed out, which are mainly associated with the heterogeneity of the distribution of alpha dose within the different target regions of the respiratory tract. (authors)

  18. Liquid scintillation counting techniques for the determination of some alpha emitting actinides: a review

    The present report is a review of the work on liquid scintillation counting techniques, for the determination of alpha emitting actinides like uranium, plutonium, americium etc; for the last three decades (1970-1999). It covers the progress that has taken place in conventional liquid scintillation counting employing various solvents, scintillators and extractants. There is gradual development in instrumentation from integral counting of alpha emitters to alpha liquid scintillation spectrometry to resolve and identify different alpha emitters. These advancements have led to Pulse Shape Analysis (PSA) and Photon Electron Rejecting Alpha Liquid Scintillation Spectrometry (PERALS) techniques for the determination of the alpha emitters in the presence of beta and gamma activity. These techniques allow the determination of actinides at very low levels which has increased their applications to almost all the fields of chemistry; be it biomedical, environmental, geological or process chemistry of nuclear fuels. The development of biphasic technique using various extractants to separate different elements and counting in presence of one another has been made possible. Inorganic scintillators have been recently developed which have the advantage of eliminating effects of quenching and presence of beta/gamma emitting actinides. This review will serve as a reference to those who want to carry out work in the field of determination of actinides using liquid scintillation counting techniques. (author)

  19. Decorporation of actinides: a review of recent research

    This paper reports progress on some of the research priorities identified in the Guidebook for the Treatment of Accidental Contamination of Workers published in 1992. It concludes: that the oral administration of DTPA could be an effective procedure for plutonium (Pu) and americium (Am) inhaled as nitrates; that 3,4,3-LI (1,2-HOPO) is the most effective siderophore analogue yet tested for the decorporation of these actinides, and thorium (Th); and that for thorium the efficacy of treatment will be strongly dependent on the radionuclide, and hence mass, likely to be incorporated under different exposure scenarios. No effective treatment regimens appear to be available for neptunium (Np) and uranium (U). (orig.)

  20. Facilities for preparing actinide or fission product-based targets

    Sors, M

    1999-01-01

    Research and development work is currently in progress in France on the feasibility of transmutation of very long-lived radionuclides such as americium, blended with an inert medium such as magnesium oxide and pelletized for irradiation in a fast neutron reactor. The process is primarily designed to produce ceramics for nuclear reactors, but could also be used to produce targets for accelerators. The Actinide Development Laboratory is part of the ATALANTE complex at Marcoule, where the CEA investigates reprocessing, liquid and solid waste treatment and vitrification processes. The laboratory produces radioactive sources; after use, their constituents are recycled, notably through R and D programs requiring such materials. Recovered americium is purified, characterized and transformed for an experiment known as ECRIX, designed to demonstrate the feasibility of fabricating americium-based ceramics and to determine the reactor transmutation coefficients.

  1. Specific sequestering agents for iron and the actinides

    The transuranium actinide ions represent one unique environmental hazard associated with the waste of the nuclear power industry. A major component associated with that waste and a potential hazard is plutonium. The synthesis of metal-ion-specific complexing agents for ions such as Pu(IV) potentially represents a powerful new approach to many of the problems posed by waste treatment. This document is a progress report of a rational approach to the synthesis of such chelating agents based on the similarities of Pu(IV) and Fe(III), the structures of naturally-occurring complexing agents which are highly specific for Fe(III), and the incorporation of the same kinds of ligating groups present in the iron complexes to make octadentate complexes highly specific for plutonium. Both thermodynamic and animal test results indicate that a relatively high degree of success has already been achieved in this aim

  2. Actinide recycle in LMFBRs as a waste management alternative

    Beaman, S.L.

    1979-08-21

    A strategy of actinide burnup in fast reactor systems has been investigated as an approach for reducing the long term hazards and storage requirements of the actinide waste elements and their decay daughters. The actinide recycle studies also included plutonium burnup studies in the event that plutonium is no longer required as a fuel. Particular emphasis was placed upon the timing of the recycle program, the requirements for separability of the waste materials, and the impact of the actinides on the reactor operations and performance. It is concluded that actinide recycle and plutonium burnout are attractive alternative waste management concepts. 25 refs., 14 figs., 34 tabs.

  3. Chemical compatibility of HLW borosilicate glasses with actinides

    During liquid storage of HLLW the formation of actinide enriched sludges is being expected. Also during melting of HLW glasses an increase of top-to-bottom actinide concentrations can take place. Both effects have been studied. Besides, the vitrification of plutonium enriched wastes from Pu fuel element fabrication plants has been investigated with respect to an isolated vitrification process or a combined one with the HLLW. It is shown that the solidification of actinides from HLLW and actinide waste concentrates will set no principal problems. The leaching of actinides has been measured in salt brine at 230C and 1150C. (orig.)

  4. Actinide recycle in LMFBRs as a waste management alternative

    A strategy of actinide burnup in fast reactor systems has been investigated as an approach for reducing the long term hazards and storage requirements of the actinide waste elements and their decay daughters. The actinide recycle studies also included plutonium burnup studies in the event that plutonium is no longer required as a fuel. Particular emphasis was placed upon the timing of the recycle program, the requirements for separability of the waste materials, and the impact of the actinides on the reactor operations and performance. It is concluded that actinide recycle and plutonium burnout are attractive alternative waste management concepts. 25 refs., 14 figs., 34 tabs

  5. Research progress on algae of the microbial crusts in arid and semiarid regions

    HU Chunxiang; ZHANG Delu; LIU Yongding

    2004-01-01

    Microbial crusts are attracting much interest in view of their possible uses in environmental conservation and ecological restoration of the arid and semiarid regions.Because algae play an irreplaceable important role in the early formation and the strengthening of microbial crusts,they are paid much more attention to than other cryptogams.In this paper,an overview of the current knowledge on the fine structure and development of microbial crust,focusing on the algal biomass,vertical distribution,succession,influential factors on algae,cohesion of soil stabilization,cementing mechanism for soil particles and the microalgal extracellular polymers is given,with particular emphasis on the authors' researches,and some prospects are put forward as well.

  6. Placental transfer of plutonium and other actinides

    The report is based on an extensive literature search. All data available from studies on placental transfer of plutonium and other actinides in man and animals have been collected and analysed, and the report presents the significant results as well as unresolved questions and knowledge gaps which may serve as a waypost to future research work. (orig./MG)

  7. Actinide and fission product partitioning and transmutation

    The third international information exchange meeting on actinide and fission product partitioning and transmutation, took place in Cadarache France, on 12-14 December 1994. The proceedings are presented in six sessions : an introduction session, the major programmes and international cooperation, the systems studies, the reactors fuels and targets, the chemistry and a last discussions session. (A.L.B.)

  8. Actinide and fission product partitioning and transmutation

    NONE

    1995-07-01

    The third international information exchange meeting on actinide and fission product partitioning and transmutation, took place in Cadarache France, on 12-14 December 1994. The proceedings are presented in six sessions : an introduction session, the major programmes and international cooperation, the systems studies, the reactors fuels and targets, the chemistry and a last discussions session. (A.L.B.)

  9. Rapid determination of actinides in asphalt samples

    A new rapid method for the determination of actinides in asphalt samples has been developed that can be used in emergency response situations or for routine analysis. If a radiological dispersive device, improvised nuclear device or a nuclear accident such as the accident at the Fukushima Nuclear Power Plant in March, 2011 occurs, there will be an urgent need for rapid analyses of many different environmental matrices, including asphalt materials, to support dose mitigation and environmental clean-up. The new method for the determination of actinides in asphalt utilizes a rapid furnace step to destroy bitumen and organics present in the asphalt and sodium hydroxide fusion to digest the remaining sample. Sample preconcentration steps are used to collect the actinides and a new stacked TRU Resin + DGA Resin column method is employed to separate the actinide isotopes in the asphalt samples. The TRU Resin plus DGA Resin separation approach, which allows sequential separation of plutonium, uranium, americium and curium isotopes in asphalt samples, can be applied to soil samples as well. (author)

  10. Treatment of actinide-containing organic waste

    A method has been developed for reducing the volume of organic wastes and recovering the actinide elements. The waste, together with gaseous oxygen (air) is introduced into a molten salt, preferably an alkali metal carbonate such as sodium carbonate. The bath is kept at 7500 - 10000C and 0.5 - 10 atm to thermally decompose and partially oxidize the waste, while substantially reducing its volume. The gaseous effluent, mainly carbon dioxide and water vapour, is vented to the atmosphere through a series of filters to remove trace amounts of actinide elements or particulate alkali metal salts. The remaining combustion products are entrained in the molten salt. Part of the molten salt-combustion product mixture is withdrawn and mixed with an aqueous medium. Insoluble combustion products are then removed from the aqueous medium and are leached with a mixture of hydrofluoric and nitric acids to solubilize the actinide elements. The actinide elements are easily recovered from the acid solution using conventional techniques. (DN)

  11. Actinide measurements by AMS using fluoride matrices

    Cornett, R. J.; Kazi, Z. H.; Zhao, X.-L.; Chartrand, M. G.; Charles, R. J.; Kieser, W. E.

    2015-10-01

    Actinides can be measured by alpha spectroscopy (AS), mass spectroscopy or accelerator mass spectrometry (AMS). We tested a simple method to separate Pu and Am isotopes from the sample matrix using a single extraction chromatography column. The actinides in the column eluent were then measured by AS or AMS using a fluoride target matrix. Pu and Am were coprecipitated with NdF3. The strongest AMS beams of Pu and Am were produced when there was a large excess of fluoride donor atoms in the target and the NdF3 precipitates were diluted about 6-8 fold with PbF2. The measured concentrations of 239,240Pu and 241Am agreed with the concentrations in standards of known activity and with two IAEA certified reference materials. Measurements of 239,240Pu and 241Am made at A.E. Lalonde AMS Laboratory agree, within their statistical uncertainty, with independent measurements made using the IsoTrace AMS system. This work demonstrated that fluoride targets can produce reliable beams of actinide anions and that the measurement of actinides using fluorides agree with published values in certified reference materials.

  12. Trends in actinide processing at Hanford

    In 1989, the mission at the Hanford Site began a dramatic and sometimes painful transition. The days of production--as we used to know it--are over. Our mission officially has become waste management and environmental cleanup. This mission change didn't eliminate many jobs--in fact, budgets have grown dramatically to support the new mission. Most all of the same skilled crafts, engineers, and scientists are still required for the new mission. This change has not eliminated the need for actinide processing, but it has certainly changed the focus that our actinide chemists and process engineers have. The focus used to be on such things as increasing capacity, improving separations efficiency, and product purity. Minimizing waste had become a more important theme in recent years and it is still a very important concept in the waste management and environmental cleanup arena. However, at Hanford, a new set of words dominates the actinide process scene as we work to deal with actinides that still reside in a variety of forms at the Hanford Site. These words are repackage, stabilize, remove, store and dispose. Some key activities in each of these areas are described in this report

  13. Report of the panel on inhaled actinides

    Some topics discussed are as follows: assessment of risks to man of inhaling actinides; use of estimates for developing protection standards; epidemiology of lung cancer in exposed human populations; development of respiratory tract models; and effects in animals: dose- and effect-modifying factors

  14. Electronic Structure of the Actinide Metals

    Johansson, B.; Skriver, Hans Lomholt

    1982-01-01

    itinerant to localized 5f electron behaviour calculated to take place between plutonium and americium. From experimental data it is shown that the screening of deep core-holes is due to 5f electrons for the lighter actinide elements and 6d electrons for the heavier elements. A simplified model for the full...

  15. Spin–orbit coupling in actinide cations

    Bagus, Paul S.; Ilton, Eugene S.; Martin, Richard L.;

    2012-01-01

    The limiting case of Russell–Saunders coupling, which leads to a maximum spin alignment for the open shell electrons, usually explains the properties of high spin ionic crystals with transition metals. For actinide compounds, the spin–orbit splitting is large enough to cause a significantly reduced...

  16. ENDF/B-5 Actinides (Rev. 86)

    This document summarizes the contents of the Actinides part of the ENDF/B-5 nuclear data library released by the US National Nuclear Data Center. This library or selective retrievals of it, are available costfree from the IAEA Nuclear Data Section upon request. The present version of the library is the Revision of 1986. (author). Refs, figs and tabs

  17. Radiochemistry Division annual progress report : 1990

    This progress report provides an account of the research and development activities of the Radiochemistry Division during the year 1990 in the areas of nuclear chemistry, actinide chemistry and spectroscopy. The main area of work in nuclear chemistry is centered around the fission process induced by reactor neutrons, and light and heavy ions on actinides and low Z (Z<80) elements. Actinide chemistry research is concerned mostly with extraction, complexation and separation of actinide ions from aqueous media using a variety of organic reagents under different experimental conditions. Spectroscopic studies include development and optimisation of chemical/analytical methods for separation and determination of trace metallic impurities and rare earths in fuel materials and EPR and microwave studies on several compounds to understand their superconducting, structural and magnetic properties. A list of publications by the scientific staff of the Division during 1990 is also given in the report. (author). 45 figs., 44 tabs

  18. Library of Recommended Actinide Decay Data, 2011

    A major objective of the nuclear data programme within the IAEA is to devise and promote improvements in the quality of nuclear data used in science and technology. Work of this nature was performed by participants in an IAEA coordinated research project (CRP) formulated in 2005 to produce an updated decay data library of important actinides recommended for adoption in various nuclear applications. The specific objectives of this project were to improve the accuracy of heavy element and actinide decay data in order to: determine more accurately the effects of these recommended data on fission reactor fuel cycles; aid in improved assessments of nuclear waste management procedures; provide more reliable decay data for nuclear safeguards; assess with greater confidence the environmental impact of specific actinides and other heavy element radionuclides generated through their decay chains; and extend the scientific knowledge of actinide decay characteristics for nuclear physics research and non-energy applications. Some CRP participants were able to perform a number of highly precise measurements, based on the availability of suitable source materials, and systematic in depth evaluations of the requested decay data. These requested data consisted primarily of half-lives, and α, β-, EC/β+, Auger electron, conversion electron, X ray and γ ray energies and emission probabilities, all with uncertainties expressed at the 1σ confidence level. The IAEA established a CRP entitled Updated Decay Data Library for Actinides in mid-2005. During the course of discussions at the coordinated research meetings, the participants agreed to undertake work programmes of measurements and evaluations, to be completed by the end of 2010. The results of the evaluation studies undertaken by the CRP are presented in Annex I. Annexes II-V include descriptions of the sources of the evaluated decay data and each individual evaluation process in detail, as well as data files in the Evaluated

  19. Advanced techniques in actinide spectroscopy (ATAS 2014). Abstract book

    In 2012, The Institute of Resource Ecology at the Helmholtz-Zentrum Dresden Rossendorf organized the first international workshop of Advanced Techniques in Actinide Spectroscopy (ATAS). A very positive feedback and the wish for a continuation of the workshop were communicated from several participants to the scientific committee during the workshop and beyond. Today, the ATAS workshop has been obviously established as an international forum for the exchange of progress and new experiences on advanced spectroscopic techniques for international actinide and lanthanide research. In comparison to already established workshops and conferences on the field of radioecology, one main focus of ATAS is to generate synergistic effects and to improve the scientific discussion between spectroscopic experimentalists and theoreticians. The exchange of ideas in particular between experimental and theoretical applications in spectroscopy and the presentation of new analytical techniques are of special interest for many research institutions working on the improvement of transport models of toxic elements in the environment and the food chain as well as on reprocessing technologies of nuclear and non-nuclear waste. Spectroscopic studies in combination with theoretical modelling comprise the exploration of molecular mechanisms of complexation processes in aqueous or organic phases and of sorption reactions of the contaminants on mineral surfaces to obtain better process understanding on a molecular level. As a consequence, predictions of contaminant's migration behaviour will become more reliable and precise. This can improve the monitoring and removal of hazardous elements from the environment and hence, will assist strategies for remediation technologies and risk assessment. Particular emphasis is placed on the results of the first inter-laboratory Round-Robin test on actinide spectroscopy (RRT). The main goal of RRT is the comprehensive molecular analysis of the actinide complex

  20. Synthesis of actinide nitrides, phosphides, sulfides and oxides

    Van Der Sluys, William G.; Burns, Carol J.; Smith, David C.

    1992-01-01

    A process of preparing an actinide compound of the formula An.sub.x Z.sub.y wherein An is an actinide metal atom selected from the group consisting of thorium, uranium, plutonium, neptunium, and americium, x is selected from the group consisting of one, two or three, Z is a main group element atom selected from the group consisting of nitrogen, phosphorus, oxygen and sulfur and y is selected from the group consisting of one, two, three or four, by admixing an actinide organometallic precursor wherein said actinide is selected from the group consisting of thorium, uranium, plutonium, neptunium, and americium, a suitable solvent and a protic Lewis base selected from the group consisting of ammonia, phosphine, hydrogen sulfide and water, at temperatures and for time sufficient to form an intermediate actinide complex, heating said intermediate actinide complex at temperatures and for time sufficient to form the actinide compound, and a process of depositing a thin film of such an actinide compound, e.g., uranium mononitride, by subliming an actinide organometallic precursor, e.g., a uranium amide precursor, in the presence of an effectgive amount of a protic Lewis base, e.g., ammonia, within a reactor at temperatures and for time sufficient to form a thin film of the actinide compound, are disclosed.

  1. Adventures in Actinide Chemistry: A Year of Exploring Uranium and Thorium in Los Alamos

    The first part of this collection of slides is concerned with considerations when working with actinides. The topics discussed in the document as a whole are the following: Actinide chemistry vs. transition metal chemistry--tools we can use; New synthetic methods to obtain actinide hydrides; Actinide metallacycles: synthesis, structure, and properties; and Reactivity of actinide metallacycles.

  2. Adventures in Actinide Chemistry: A Year of Exploring Uranium and Thorium in Los Alamos

    Pagano, Justin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-01-08

    The first part of this collection of slides is concerned with considerations when working with actinides. The topics discussed in the document as a whole are the following: Actinide chemistry vs. transition metal chemistry--tools we can use; New synthetic methods to obtain actinide hydrides; Actinide metallacycles: synthesis, structure, and properties; and Reactivity of actinide metallacycles.

  3. A Nitrogen Inventory of Major Water Regions Across the USA as a Benchmark for Future Progress in Mitigating Nitrogen Pollution

    Boyer, E. W.; Galloway, J. N.; Alexander, R. B.

    2012-12-01

    We present a contemporary inventory of reactive nitrogen (Nr) inputs and, air, and surface waters throughout major water regions in the United States. Inputs of Nr to the nation and the world have been increasing, largely due to human activities associated with food production and energy consumption via the combustion of fossil fuels and biofuels. Despite the obvious essential benefits of a plentiful supply of food and energy, the adverse consequences associated with the accumulation of Nr in the environment are large. Most of the Nr created by anthropogenic activities is released to the environment, often with unintended negative consequences. The greater the inputs of Nr to the landscape, the greater the potential for negative effects, caused by greenhouse gas production, ground level ozone, acid deposition, and Nr overload that can contribute to climate change, degradation of soils and vegetation, acidification of surface waters, coastal eutrophication, hypoxia and habitat loss. Here, we present a consistent accounting method for quantifying Nr sources and transport that was used in our inventory, and discuss associated data needs for tallying Nr inputs at regional scales. The inventory is a necessary tool for exploring the role of Nr contributed to the environment from various sources (e.g., from fertilizers, manure, biological fixation, human waste, atmospheric deposition) and from various industrial sectors (e.g., from agriculture, transportation, electricity generation). Agriculture and use of fertilizers to produce food, feed, and fiber (including bioenergy and biological nitrogen fixation) and combustion of fossil fuels are the largest sources of Nr released into the environment in the USA. Our inventory can be used as a benchmark of the current Nr situation against which future progress can be assessed in varying regions of the country, amidst changing Nr inputs and implementation of policy and management strategies to mitigate Nr pollution.

  4. Utilization of Minor Actinides as a Fuel Component for Ultra-Long Life Bhr Configurations: Designs, Advantages and Limitations

    Dr. Pavel V. Tsvetkov

    2009-05-20

    This project assessed the advantages and limitations of using minor actinides as a fuel component to achieve ultra-long life Very High Temperature Reactor (VHTR) configurations. Researchers considered and compared the capabilities of pebble-bed and prismatic core designs with advanced actinide fuels to achieve ultra-long operation without refueling. Since both core designs permit flexibility in component configuration, fuel utilization, and fuel management, it is possible to improve fissile properties of minor actinides by neutron spectrum shifting through configuration adjustments. The project studied advanced actinide fuels, which could reduce the long-term radio-toxicity and heat load of high-level waste sent to a geologic repository and enable recovery of the energy contained in spent fuel. The ultra-long core life autonomous approach may reduce the technical need for additional repositories and is capable to improve marketability of the Generation IV VHTR by allowing worldwide deployment, including remote regions and regions with limited industrial resources. Utilization of minor actinides in nuclear reactors facilitates developments of new fuel cycles towards sustainable nuclear energy scenarios.

  5. Utilization of Minor Actinides as a Fuel Component for Ultra-Long Life VHTR Configurations: Designs, Advantages and Limitations

    This project assessed the advantages and limitations of using minor actinides as a fuel component to achieve ultra-long life Very High Temperature Reactor (VHTR) configurations. Researchers considered and compared the capabilities of pebble-bed and prismatic core designs with advanced actinide fuels to achieve ultra-long operation without refueling. Since both core designs permit flexibility in component configuration, fuel utilization, and fuel management, it is possible to improve fissile properties of minor actinides by neutron spectrum shifting through configuration adjustments. The project studied advanced actinide fuels, which could reduce the long-term radio-toxicity and heat load of high-level waste sent to a geologic repository and enable recovery of the energy contained in spent fuel. The ultra-long core life autonomous approach may reduce the technical need for additional repositories and is capable to improve marketability of the Generation IV VHTR by allowing worldwide deployment, including remote regions and regions with limited industrial resources. Utilization of minor actinides in nuclear reactors facilitates developments of new fuel cycles towards sustainable nuclear energy scenarios.

  6. Distribuição regional do suor durante exercício progressivo até a fadiga Sweat regional distribution during progressive exercise until fatigue

    João Batista Ferreira Júnior

    2009-12-01

    Full Text Available A partir da hipótese evolutiva de que a cabeça humana precisa ser resfriada de forma especial, o objetivo do presente estudo foi verificar se a sudorese seria maior na testa do que nas demais regiões do corpo durante o exercício progressivo até a fadiga (EPF. Em 17 voluntários (23 ± 2 anos, 76,93 ± 7,74 kg, 179 ± 7 cm e 1,9 ± 0,1 m² foram medidos a taxa de sudorese local (TSlocal, o número de glândulas de suor ativas (GSA e taxa de suor por GSA (TSlocal.GSA-1 em oito regiões do corpo (testa, costas, peito, braço, antebraço, mão, coxa e perna durante o EPF em cicloergômetro. A TSlocal da testa foi maior que todas as outras regiões e a TSlocal do peito foi maior apenas que a da coxa. O número de GSA da testa foi maior do que em todas as outras regiões, e a GSA da mão foi maior que do peito, braço, coxa e perna. A TSlocal.GSA-1 da testa foi maior do que as do braço, antebraço, mão e coxa, e a TSlocal.GSA-1 das costas e do peito foram maiores que do antebraço e mão. A produção de suor da parte superior do corpo (testa, costas, peito, braço, antebraço, mão foi maior que a inferior (coxa e perna. Concluiu-se que o EPF desencadeou um padrão de produção de suor maior na cabeça que pode estar relacionado à maior convecção nas regiões mais altas do corpo.Considering the hypothesis of human selective brain cooling during exercise should depend on greater sweating mechanism in the forehead. The purpose of this study was verify variations of sweat production between body regions during progressive exercise until fatigue (PEF. Seventeen subjects (23 ± 2 years old, 76.93 ± 7.74 kg, 179 ± 7 cm and 1.9 ± 0.1 m² volunteered for this study. Local sweat rate (STlocal, number of active sweat glands (ASG and sweat rate for ASG (STlocal.ASG-1 in eight body regions (forehead, back, chest, arm, forearm, hand, leg and calf were measured during PEF in cyclergometer. The STlocal of the forehead was higher than in all others

  7. The separation and recycling of actinides: a review of the state of the art

    The principal objective of this study is to assess the state of the art of separating the actinides and recycling them to reactors. To this end, the literature has been surveyed, discussions have been held at the contractors' laboratories, AERE, Harwell, UK and ECN, Petten, Netherlands, and visits have been paid to the establishments where relevant work is in progress. The study does not include any new experimental work, but a certain amount of computation has been carried out to support it. A programme of installation of reactors within the European Communities was supplied for the purposes of this study. The prospective generating facilities in GW(e) are given. The situation in the various areas of investigation involved is as follows: nuclear physics: favourable; chemical separations: difficult, but probably feasible; nuclear incineration strategies: little studied so far; fuel and fuel elements containing recycled actinides: little development so far

  8. Research and development for the fabrication of minor actinide-bearing fuel materials and technologies

    The transmutation of minor actinides (MA) in 4th-generation reactors can be envisioned in homogeneous or heterogeneous mode. Minor actinide-bearing blankets (MABB) -- fuel for heterogeneous transmutation comprising 10 to 20% MA dispersed in a UO2 matrix -- are largely unknown and warrant further research on the fabrication and properties of the materials, on their evolution under self-irradiation, and on their behavior in the reactor. This article summarizes progress in co conversion of uranium-americium compounds by oxalate precipitation or ion exchange resins. It also describes current R&D on MABB fabrication by powder metallurgy or spherical particle metallurgy. The fabrication processes in teleoperated shielded cells are discussed together with the technologies applicable to MABB fabrication equipment. (author)

  9. Electronic structure of high oxidation state actinide species: Theoretical and experimental approaches

    Hilaire, Sandrine; Guillaumont, Dominique; Gutierez, Fabien; Denauwer, Christophe; Meyer, Daniel [CEA-DEN Ma DRCP/SCPS/LCAM BP 17171 30207 Bagnols sur ceze (France); Wastin, Franck; Colineau, Eric; Gouder, Thomas; Rebizant, Jean [EC-JRC Institute for Transuranium Elements, Postfach 2340 Karlsruhe (Germany); Berthet, Jean-Claude [Service de Chimie Moleculaire, Bat. 125, pi e 25, Gif sur Yvette 91911 cedex (France); Simoni, Eric [IPN/Universite Paris XI, Orsay 91406 (France)

    2006-07-01

    Early actinides (U, Np, Pu, Am) show a particular linear bond actinyl-type structure in their highest oxidation state. The multiple-bond nature of this chemical pattern contributes to a drastic diminution of the charge on the metallic core inducing a strong stabilization of these high oxidation states. The potential participation of the early actinide 5f orbitals in the valence molecular shell is supposed to be one of the most important engines of this chemical specificity. In order to progress in the comprehension of this behavior, a study of the electronic and the geometric structures of some actinyl complexes with different electronic configurations is undertaken using theoretical and experimental approaches. (authors)

  10. Minor actinide transmutation on PWR burnable poison rods

    Highlights: • Key issues associated with MA transmutation are the appropriate loading pattern. • Commercial PWRs are the only choice to transmute MAs in large scale currently. • Considerable amount of MA can be loaded to PWR without disturbing keff markedly. • Loading MA to PWR burnable poison rods for transmutation is an optimal loading pattern. - Abstract: Minor actinides are the primary contributors to long term radiotoxicity in spent fuel. The majority of commercial reactors in operation in the world are PWRs, so to study the minor actinide transmutation characteristics in the PWRs and ultimately realize the successful minor actinide transmutation in PWRs are crucial problem in the area of the nuclear waste disposal. The key issues associated with the minor actinide transmutation are the appropriate loading patterns when introducing minor actinides to the PWR core. We study two different minor actinide transmutation materials loading patterns on the PWR burnable poison rods, one is to coat a thin layer of minor actinide in the water gap between the zircaloy cladding and the stainless steel which is filled with water, another one is that minor actinides substitute for burnable poison directly within burnable poison rods. Simulation calculation indicates that the two loading patterns can load approximately equivalent to 5–6 PWR annual minor actinide yields without disturbing the PWR keff markedly. The PWR keff can return criticality again by slightly reducing the boric acid concentration in the coolant of PWR or removing some burnable poison rods without coating the minor actinide transmutation materials from PWR core. In other words, loading minor actinide transmutation material to PWR does not consume extra neutron, minor actinide just consumes the neutrons which absorbed by the removed control poisons. Both minor actinide loading patterns are technically feasible; most importantly do not need to modify the configuration of the PWR core and

  11. Measuring Progress on the Control of Porcine Reproductive and Respiratory Syndrome (PRRS at a Regional Level: The Minnesota N212 Regional Control Project (Rcp as a Working Example.

    Pablo Valdes-Donoso

    Full Text Available Due to the highly transmissible nature of porcine reproductive and respiratory syndrome (PRRS, implementation of regional programs to control the disease may be critical. Because PRRS is not reported in the US, numerous voluntary regional control projects (RCPs have been established. However, the effect of RCPs on PRRS control has not been assessed yet. This study aims to quantify the extent to which RCPs contribute to PRRS control by proposing a methodological framework to evaluate the progress of RCPs. Information collected between July 2012 and June 2015 from the Minnesota Voluntary Regional PRRS Elimination Project (RCP-N212 was used. Demography of premises (e.g. composition of farms with sows = SS and without sows = NSS was assessed by a repeated analysis of variance. By using general linear mixed-effects models, active participation of farms enrolled in the RCP-N212, defined as the decision to share (or not to share PRRS status, was evaluated and used as a predictor, along with other variables, to assess the PRRS trend over time. Additionally, spatial and temporal patterns of farmers' participation and the disease dynamics were investigated. The number of farms enrolled in RCP-N212 and its geographical coverage increased, but the proportion of SS and NSS did not vary significantly over time. A significant increasing (p<0.001 trend in farmers' decision to share PRRS status was observed, but with NSS producers less willing to report and a large variability between counties. The incidence of PRRS significantly (p<0.001 decreased, showing a negative correlation between degree of participation and occurrence of PRRS (p<0.001 and a positive correlation with farm density at the county level (p = 0.02. Despite a noted decrease in PRRS, significant spatio-temporal patterns of incidence of the disease over 3-weeks and 3-kms during the entire study period were identified. This study established a systematic approach to quantify the effect of RCPs on

  12. Method to determine actinide pollution in water

    This patent describes a process for measuring small amounts, of actinide pollution in fluidic samples by use of solid state track recording devices. It comprises: containing a sample to be tested, containing small amounts of less than 3E-12 Curies per cubic centimeter of actinide pollution, in a sample cell defining an internal chamber and having means for ingress and egress and means for establishing a fluidic sample therein, the sample cell being substantially transparent to thermal neutron radiation and the internal chamber defined therein being configured to constitute a fluidic sample therein as an asymptotic fluid fission source; positioning a solid state track recorder within the internal chamber defined by the sample cell, so that the solid state track recorder has a radiation viewing window through an asymptotic thickness of a fluidic sample contained in the sample cell; capturing at least an asymptotic amount of fluidic sample in the sample cell

  13. Microbial Transformations of Actinides and Other Radionuclides

    Francis,A.J.; Dodge, C. J.

    2009-01-07

    Microorganisms can affect the stability and mobility of the actinides and other radionuclides released from nuclear fuel cycle and from nuclear fuel reprocessing plants. Under appropriate conditions, microorganisms can alter the chemical speciation, solubility and sorption properties and thus could increase or decrease the concentrations of radionuclides in solution in the environment and the bioavailability. Dissolution or immobilization of radionuclides is brought about by direct enzymatic action or indirect non-enzymatic action of microorganisms. Although the physical, chemical, and geochemical processes affecting dissolution, precipitation, and mobilization of radionuclides have been extensively investigated, we have only limited information on the effects of microbial processes and biochemical mechanisms which affect the stability and mobility of radionuclides. The mechanisms of microbial transformations of the major and minor actinides U, Pu, Cm, Am, Np, the fission products and other radionuclides such as Ra, Tc, I, Cs, Sr, under aerobic and anaerobic conditions in the presence of electron donors and acceptors are reviewed.

  14. Actinide and fission product separation and transmutation

    NONE

    1991-07-01

    The first international information exchange meeting on actinide and fission product separation and transmutation, took place in Mito in Japan, on 6-8 November 1990. It starts with a number of general overview papers to give us some broad perspectives. Following that it takes a look at some basic facts about physics and about the quantities of materials it is talking about. Then it proceeds to some specific aspects of partitioning, starting with evolution from today commercially applied processes and going on to other possibilities. At the end of the third session it takes a look at the significance of partitioning and transmutation of actinides before it embarks on two sessions on transmutation, first in reactors and second in accelerators. The last session is designed to throw back into the discussion the main points which need to be looked at when considering future work in this area. (A.L.B.)

  15. Interaction of actinide cations with synthetic polyelectrolytes

    The binding of Am+3, Th+4 and UO2+2 to polymaleic acid, polyethylenemaleic acid and polymethylvinylethermaleic acid has been measured by a solvent extraction technique at 250C and either 0.02 or 0.10 M ionic strength. The solutions were buffered over a pH range such that the percent of carboxylate groups ionized ranged from 25 to 74%. The binding was described by two constants, β1 and β2, which were evaluated after correction for complexation of the actinide cations by acetate and hydrolysis. For comparable degrees of ionization, all three polyelectrolytes showed similar binding strengths. In general, these results indicated that the binding of actinides to these synthetic polyelectrolytes is basically similar to that of natural polyelectrolytes such as humic and fulvic acids. (orig.)

  16. Actinide and fission product separation and transmutation

    The first international information exchange meeting on actinide and fission product separation and transmutation, took place in Mito in Japan, on 6-8 November 1990. It starts with a number of general overview papers to give us some broad perspectives. Following that it takes a look at some basic facts about physics and about the quantities of materials it is talking about. Then it proceeds to some specific aspects of partitioning, starting with evolution from today commercially applied processes and going on to other possibilities. At the end of the third session it takes a look at the significance of partitioning and transmutation of actinides before it embarks on two sessions on transmutation, first in reactors and second in accelerators. The last session is designed to throw back into the discussion the main points which need to be looked at when considering future work in this area. (A.L.B.)

  17. ACSEPT-Partitioning technologies and actinide science: Towards pilot facilities in Europe

    Highlights: → ACSEPT works at developing actinide separation processes for advanced fuel cycles. → ACSEPT develops both aqueous and pyrochemical actinide separation processes. → Homogeneous and heterogeneous recycling strategies are both considered in ACSEPT. → Training and education in actinide chemistry are important issues addressed by ACSEPT. - Abstract: Actinide recycling by separation and transmutation is considered worldwide and particularly in several European countries as one of the most promising strategies to reduce the inventory of radioactive waste and to optimise the use of natural resources. With its multidisciplinary consortium of 34 partners from 12 European countries plus Australia and Japan, the European Research Project ACSEPT (Actinide reCycling by SEParation and Transmutation) aims at contributing to the development of this strategy by studying both hydrometallurgical and pyrochemical partitioning routes. ACSEPT is organised into three technical domains: (i)Considering technically mature aqueous separation processes, ACSEPT works to optimise and select the most promising ones dedicated either to actinide partitioning (for the heterogeneous recycling of actinides in ADS target or specific actinide bearing blanket fuels in fast reactor) or to grouped actinide separation (for the homogeneous recycling of the actinides in fast reactor fuels). In addition, dissolution and conversion studies are underway taking into account the specific requirements of these specific fuels. (ii)Concerning pyrochemical separation processes, ACSEPT focuses on the enhancement of the two reference cores processes selected within FP6-EUROPART. R and D efforts are also devoted to key scientific and technical issues compulsory to set up a complete separation process (head-end steps, salt treatment for recycling and waste management). (iii)By integrating all the experimental results in engineering and system studies, both in hydro and pyro domains, ACSEPT will

  18. Sigma Team for Advanced Actinide Recycle FY2015 Accomplishments and Directions

    Moyer, Bruce A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-09-30

    The Sigma Team for Minor Actinide Recycle (STAAR) has made notable progress in FY 2015 toward the overarching goal to develop more efficient separation methods for actinides in support of the United States Department of Energy (USDOE) objective of sustainable fuel cycles. Research in STAAR has been emphasizing the separation of americium and other minor actinides (MAs) to enable closed nuclear fuel recycle options mainly within the paradigm of aqueous reprocessing of used oxide nuclear fuel dissolved in nitric acid. Its major scientific challenge concerns achieving selectivity for trivalent actinides vs lanthanides. Not only is this challenge yielding to research advances, but technology concepts such as ALSEP (Actinide Lanthanide Separation) are maturing toward demonstration readiness. Efforts are organized in five task areas: 1) combining bifunctional neutral extractants with an acidic extractant to form a single process solvent, developing a process flowsheet, and demonstrating it at bench scale; 2) oxidation of Am(III) to Am(VI) and subsequent separation with other multivalent actinides; 3) developing an effective soft-donor solvent system for An(III) selective extraction using mixed N,O-donor or all-N donor extractants such as triazinyl pyridine compounds; 4) testing of inorganic and hybrid-type ion exchange materials for MA separations; and 5) computer-aided molecular design to identify altogether new extractants and complexants and theory-based experimental data interpretation. Within these tasks, two strategies are employed, one involving oxidation of americium to its pentavalent or hexavalent state and one that seeks to selectively complex trivalent americium either in the aqueous phase or the solvent phase. Solvent extraction represents the primary separation method employed, though ion exchange and crystallization play an important role. Highlights of accomplishments include: Confirmation of the first-ever electrolytic oxidation of Am(III) in a

  19. Actinide co-ordination and discrimination by human transferrin

    The design and evaluation of synthetic chelating agents which are specific for the actinide(IV) ions are described. The initial approach has been based on the biological and chemical similarities of Pu(IV) and Fe(III). In particular, using a philosophy influenced by naturally occurring ferric ion chelating agents, tetracatechoylamide ligands have been developed for the actinides. The test of the degree to which there was an actinide-specific complexing agent has been based on studies using Pu4+ as a biological contaminant. For a chelating agent to be able to sequester actinides effectively, it must remove actinides from actinide(IV)-protein complexes. The complexation chemistry of Th(IV)-transferrin system is described. The evidence suggests that, based on a size criterion, Th(IV) may be a poor biological model for Pu(IV) in some cases, with U(IV) being a somewhat better model. (author)

  20. Actinides reduction by recycling in a thermal reactor

    This work is directed towards the evaluation of an advanced nuclear fuel cycle in which radioactive actinides could be recycled to remove most of the radioactive material; firstly a production reference of actinides in standard nuclear fuel of uranium at the end of its burning in a BWR reactor is established, after a fuel containing plutonium is modeled to also calculate the actinides production in MOX fuel type. Also it proposes a design of fuel rod containing 6% of actinides in a matrix of uranium from the tails of enrichment, then four standard uranium fuel rods are replaced by actinides rods to evaluate the production and transmutation thereof, the same procedure was performed in the fuel type MOX and the end actinide reduction in the fuel was evaluated. (Author)

  1. Thermal properties of minor actinide targets

    Staicu, Dragos; Somers, Joseph; FERNANDEZ CARRETERO Asuncion; KONINGS Rudy

    2014-01-01

    The thermal properties of minor actinides targets for the management of high level and long lived radioactive waste are investigated. The microstructure, thermal diffusivity and specific heat of (Pu,Am)O2, (Zr,Pu,Am)O2, (Zr,Y,Am)O2, (Zr,Y,Pu,Am)O2 and CERMETS with Mo matrix are characterised in order to assess the safety limits of these materials.

  2. SPECIFIC SEQUESTERING AGENTS FOR THE ACTINIDES

    Raymond, Kenneth N.; Smith, William L.; Weitl, Frederick L.; Durbin, Patricia W.; Jones, E.Sarah; Abu-Dari, Kamal; Sofen, Stephen R.; Cooper, Stephen R.

    1979-09-01

    This paper summarizes the current status of a continuing project directed toward the synthesis and characterization of chelating agents which are specific for actinide ions - especially Pu(IV) - using a biomimetic approach that relies on the observation that Pu(IV) and Fe(III) has marked similarities that include their biological transport and distribution in mammals. Since the naturally-occurring Fe(III) sequestering agents produced by microbes commonly contain hydroxamate and catecholate functional groups, these groups should complex the actinides very strongly and macrocyclic ligands incorporating these moieties are being prepared. We have reported the isolation and structure analysis of an isostructural series of tetrakis(catecholato) complexes with the general stoichiometry Na{sub 4}[M(C{sub 6}H{sub 4}O{sub 2}){sub 4}] • 21 H{sub 2}O (M = Th, U, Ce, Hf). These complexes are structural archetypes for the cavity that must be formed if an actinide-specific sequestering agent is to conform ideally to the coordination requirements of the central metal ion. The [M(cat){sub 4}]{sup 4-} complexes have the D{sub 2d} symmetry of the trigonal-faced dodecahedron.. The complexes Th [R'C(0)N(O)R]{sub 4} have been prepared where R = isopropyl and R' = t-butyl or neopentyl. The neopentyl derivative is also relatively close to an idealized D{sub 2d} dodecahedron, while the sterically more hindered t-butyl compound is distorted toward a cubic geometry. The synthesis of a series of 2, 3-dihydroxy-benzoyl amide derivatives of linear and cyclic tetraaza- and diazaalkanes is reported. Sulfonation of these compounds improves the metal complexation and in vivo removal of plutonium from test animals. These results substantially exceed the capabilities of compounds presently used for the therapeutic treatment of actinide contamination.

  3. The electrochemical properties of actinide amalgams

    Standard potentials are selected for actinides (An) and their amalgams. From the obtained results, energy characteristics are calculated and analyzed for alloy formation in An-Hg systems. It is found that solutions of the f-elements in mercury are very close in properties to amalgams of the alkali and alkaline-earth metals, except that, for the active Group III metals, the ion skeletons have a greater number of realizable charged states in the condensed phase

  4. Actinide and fission product partitioning and transmutation

    NONE

    1997-07-01

    The fourth international information exchange meeting on actinide and fission product partitioning and transmutation, took place in Mito City in Japan, on 111-13 September 1996. The proceedings are presented in six sessions: the major programmes and international cooperation, the partitioning and transmutation programs, feasibility studies, particular separation processes, the accelerator driven transmutation, and the chemistry of the fuel cycle. (A.L.B.)

  5. The actinide waste problem in perspective

    The long lived alpha emitting actinide waste nuclides of transplutonium elements such as Np, Am, Cm etc (also called Byproduct Actinides or BPA for short) which are proposed to be disposed of as part of High Active Waste (HAW) in deep underground geological repositories has been a persistent source of concern to opponents and critics of nuclear fission energy. In this context the recent finding of the authors that each and every transuranium nuclide, without exception, can independently support a self sustaining chain reaction raises the important philosophical question: Is it justified to continue to refer to these nuclides as nuclear waste ? Our computations have revealed that the Ksub(eff) of an assembly of each of these nuclides increases linearly with the fissility parameter (Z2/A), its threshold value for Ksub(eff) to exceed unity being 34.1 for fissile (odd neutron) nuclides and 34.9 for fissible (even neutron) nuclides. In other words higher the (Z2/A) better is its performance as a fission reactor fuel. This finding suggests that the long lived actinide waste problem can be solved by separating all the actinide nuclides from the High Active Waste stream and recycling them back into any hard spectrum fission reactor. The studies strongly support the concept of partitioning-transmutation (p-t) revived with great enthusiasm in Japan under the banner of the OMEGA proposal. However it is found that there is no need to resort to any exotic devices such as proton accelerators or fusion reactor blankets for nuclear incineration. In the context of the 232Th/233U fuel cycle it is worth noting that the quantum of transuranium nuclides generated per se is smaller by several orders of magnitude as compared to that arising from 235U/238U bearing fuels. Thus on the whole it appears that in the thorium fuel cycle partitioning and recycle of byproduct nuclides would be a less cumbersome undertaking. (author). 26 refs., 6 figs., 3 tabs

  6. Actinide and fission product partitioning and transmutation

    The fourth international information exchange meeting on actinide and fission product partitioning and transmutation, took place in Mito City in Japan, on 111-13 September 1996. The proceedings are presented in six sessions: the major programmes and international cooperation, the partitioning and transmutation programs, feasibility studies, particular separation processes, the accelerator driven transmutation, and the chemistry of the fuel cycle. (A.L.B.)

  7. Thermodynamics and biogeochemistry of lanthanides and actinides

    Periodicity of changes in specific values of heat capacity and entropy of chemical elements, lanthanides, actinides, separating or transition elements, first of all, depending on their ordinal number, was considered. It is shown that entropy minima separate the chemical elements into light-weight and more heavy ones. The universal separation is fundamental, as it dictates the difference of the chemical elements not only in terms of thermodynamic, but also metallogenic, biogeochemical and physical properties, as well

  8. Strength of Coriolis alignment in actinide nuclei

    Analysis of aligned angular momenta i/sub α/(ω) in different rotational bands extracted from experimental data with a linear spin term approx.BI in the formulas for E/sub rot/(I) reveal that, in actinide nuclei in the levels with modest spin I< or =23, i/sub α/(ω) usually is very small (< or approx. =0.7), i.e., is much smaller than in rare earth nuclei

  9. In vitro removal of actinide (IV) ions

    Weitl, Frederick L.; Raymond, Kenneth N.

    1982-01-01

    A compound of the formula: ##STR1## wherein X is hydrogen or a conventional electron-withdrawing group, particularly --SO.sub.3 H or a salt thereof; n is 2, 3, or 4; m is 2, 3, or 4; and p is 2 or 3. The present compounds are useful as specific sequestering agents for actinide (IV) ions. Also described is a method for the 2,3-dihydroxybenzamidation of azaalkanes.

  10. Angular distributions in the neutron-induced fission of actinides

    In 2003 the n_TOF Collaboration performed the fission cross section measurement of several actinides ($^{232}$Th, $^{233}$U, $^{234}$U, $^{237}$Np) at the n_TOF facility using an experImental setup made of Parallel Plate Avalanche Counters (PPAC). The method based on the detection of the 2 fragments in coincidence allowed to clearly disentangle the fission reactions among other types of reactions occurring in the spallation domain. We have been therefore able to cover the very broad neutron energy range 1eV-1GeV, taking full benefit of the unique characteristics of the n_TOF facility. Figure 1 shows an example obtained in the case of $^{237}$Np where the n_ TOF measurement showed that the cross section was underestimated by a large factor in the resonance region.