WorldWideScience

Sample records for actinide 5f states

  1. Recent advances in the 5f-relevant electronic states and unconventional superconductivity of actinide compounds

    International Nuclear Information System (INIS)

    Haga, Yoshinori; Sakai, Hironori; Kambe, Shinsaku

    2007-01-01

    Recent advances in the understanding of the 5f-relevant electronic states and unconventional superconducting properties are reviewed in actinide compounds of UPd 2 Al 3 . UPt 3 , URu 2 Si 2 , UGe 2 , and PuRhGa 5 . These are based on the experimental results carried out on high-quality single crystal samples, including transuranium compounds, which were grown by using combined techniques. The paring state and the gap structure of these superconductors are discussed, especially for the corresponding Fermi surfaces which were clarified by the de Haas-van Alphen experiment and the energy band calculations. A detailed systematic study using the NQR/NMR spectroscopy reveals the d-wave superconductivity in PuRhGa 5 and the difference of magnetic excitations due to the difference of ground states in U-, Np-, and Pu-based AnTGa 5 (T: transition metal) compounds. (author)

  2. Dependence of actinide solid state chemistry and physics on the changing role of the 5f-electrons

    International Nuclear Information System (INIS)

    Haire, R.G.

    1992-01-01

    It is well established that the chemistry, physics, and material science of the actinides do not reflect perfectly a series of elements with a regular increase in the number of localized f-electrons (f-orbital occupation). This situation results from the changing role of the 5f-electrons across the series. Therefore, a full understanding of the properties of the individual elements necessitates an understanding of the series as a whole. The changing influence of the f-electrons is reflected in many of the actinide's properties. Systematic comparisons of selected high-temperature and high-pressure behaviors of actinide materials are discussed to demonstrate the variable nature and roles of the f-electrons, as well as their susceptibility to experimental parameters. (author)

  3. Dependence of actinide solid state chemistry and physics on the changing role of the 5f-electrons

    International Nuclear Information System (INIS)

    Haire, R.G.

    1992-01-01

    It is well established that the chemistry, physics, and material science of the actinides do not reflect perfectly a series of elements with a regular increase in the number of localized f-electrons (f-orbital occupation). This situation results from the hanging role of the 5f-electrons across the series. Therefore, a full understanding of the properties of the individual elements necessitates an understanding of the series as a whole. The changing influence of the f-electrons is reflected in many of the actinide's properties. Systematic comparisons of selected high-temperature and high-pressure behaviors of actinide materials are discussed to demonstrate the variable nature and roles of the f-electrons, as well as their susceptibility to experimental parameters

  4. Presence and Character of the 5f Electrons in the Actinide Metals

    DEFF Research Database (Denmark)

    Johansson, B.; Skriver, Hans Lomholt; Mårtensson, N.

    1980-01-01

    The sensitivity of the Image level binding energy to the occupation of the 5f orbital is pointed out and used to demonstrate the presence of 5f electrons in the uranium metal. It is suggested that the valence band spectrum of uranium might contain satellites originating from excitations...... to localized 5f-electron configurations. Different kinds of core-hole screenings are discussed for the actinide metals as well as the difference between inner and outer core electron ionizations. Finally, the question of itinerant versus localized 5f behaviour is treated by means of a total energy comparison...

  5. Systematic analysis of spectroscopic characteristics of the lanthanide and actinide ions with the 4f{sup N−1}5d and 5f{sup N−1}6d electronic configurations in a free state

    Energy Technology Data Exchange (ETDEWEB)

    Ma, C.-G. [College of Mathematics and Physics, Chongqing University of Posts and Telecommunications, Chongqing 400065 (China); Brik, M.G., E-mail: brik@fi.tartu.ee [College of Mathematics and Physics, Chongqing University of Posts and Telecommunications, Chongqing 400065 (China); Institute of Physics, University of Tartu, Riia 142, Tartu 51014 (Estonia); Institute of Physics, Jan Dlugosz University, Armii Krajowej 13/15, PL-42200 Czestochowa (Poland); Tian, Y.; Li, Q.-X. [College of Mathematics and Physics, Chongqing University of Posts and Telecommunications, Chongqing 400065 (China)

    2014-08-01

    Highlights: • Calculated spectroscopic parameters of f{sup N−1}d configurations of the 4f and 5f ions. • Relations between the Slater parameters, spin–orbit constant, atomic number were found. • Barycenters of the electronic configuration energies were calculated. • Obtained relations reduce the number of independent terms in a free ion Hamiltonian. - Abstract: Systematic consideration of the spectroscopic properties of the f{sup N−1}d excited electronic configurations of the di-, tri- and tetravalent lanthanide and actinide ions in a free state is presented. Variations of the Hartree–Fock calculated Slater parameters for the f{sup N−1}d electron configurations, spin–orbit (SO) interaction constant ζ for the f and d electrons, and averaged values of the second, fourth and sixth powers of the 4f, 5f, 5d, 6d electrons’ radial coordinate across both series were considered; functional dependencies between the mentioned quantities were obtained. It has been shown that the Coulomb interaction parameters F{sup 2}(ff), F{sup 4}(ff), and F{sup 6}(ff) for the f{sup N−1} core increase linearly with the atomic number Z, whereas the direct and exchange Coulomb parameters F{sup 2}(fd), F{sup 4}(fd), G{sup 1}(fd), G{sup 3}(fd), G{sup 5}(fd) for the f{sup N−1}d configuration decrease linearly with Z. Since the SO interaction constant ζ{sup 1/4} is also proportional to Z, it was possible to find linear relationships between the Coulomb interaction parameters and SO constants for the f and d electrons, which effectively reduce the number of independent parameters in the free ion Hamiltonian. The constraining relations between the free ion Hamiltonian’s parameters obtained in the present paper can be used for simulations of the f–d transition spectra of these ions in various crystals.

  6. Role of 5f electrons in the structural stability of light actinide (Th-U) mononitrides under pressure.

    Science.gov (United States)

    Modak, P; Verma, Ashok K

    2016-03-28

    Pressure induced structural sequences and their mechanism for light actinide (Th-U) mononitrides were studied as a function of 5f-electron number using first-principles total energy and electronic structure calculations. Zero pressure lattice constants, bulk module and C11 elastic module vary systematically with 5f-electron number implying its direct role on crystal binding. There is a critical 5f-electron number below which the system makes B1-B2 and above it B1-R3̄m-B2 structural sequence under pressure. Also, the B1-B2 transition pressure increases with increasing 5f-electron number whereas an opposite trend is obtained for the B1-R3̄m transition pressure. The ascending of N p anti-bonding states through the Fermi level at high pressure is responsible for the structural instability of the system. Above the critical 5f-electron number in the system a narrow 5f-band occurs very close to the Fermi level which allows the system to lower its symmetry via band Jahn-Teller type lattice distortion and the system undergoes a B1-R3̄m phase transition. However, below the critical 5f-electron number this mechanism is not favorable due to a lack of sufficient 5f-state occupancy and thus the system undergoes a B1-B2 phase transition like other ionic solids.

  7. Itinerant ferromagnetism in actinide 5 f -electron systems: Phenomenological analysis with spin fluctuation theory

    Science.gov (United States)

    Tateiwa, Naoyuki; Pospíšil, Jiří; Haga, Yoshinori; Sakai, Hironori; Matsuda, Tatsuma D.; Yamamoto, Etsuji

    2017-07-01

    We have carried out an analysis of magnetic data in 69 uranium, 7 neptunium, and 4 plutonium ferromagnets with the spin fluctuation theory developed by Takahashi [Y. Takahashi, J. Phys. Soc. Jpn. 55, 3553 (1986), 10.1143/JPSJ.55.3553]. The basic and spin fluctuation parameters of the actinide ferromagnets are determined and the applicability of the spin fluctuation theory to actinide 5 f system has been discussed. Itinerant ferromagnets of the 3 d transition metals and their intermetallics follow a generalized Rhodes-Wohlfarth relation between peff/ps and TC/T0 , viz., peff/ps∝(TC/T0) -3 /2 . Here, ps, peff, TC, and T0 are the spontaneous and effective magnetic moments, the Curie temperature, and the width of spin fluctuation spectrum in energy space, respectively. The same relation is satisfied for TC/T0uranium and neptunium ferromagnets below (TC/T0)kink=0.32 ±0.02 , where a kink structure appears in relation between the two quantities. ps increases more weakly above (TC/T0)kink. A possible interpretation with the TC/T0 dependence of ps is given.

  8. Influence of 5f electrons on structure and bonding in the actinide-hydrogen intermetallics

    International Nuclear Information System (INIS)

    Ward, J.W.

    1984-01-01

    Complexa phases form for the Th + H and U + H systems that are found with no other metals. In the Pa + H system, simple bcc C15 Laves and A15 phases can form, dependent on temperature and composition. The phase transformations appear to b magnetically driven, as a resutl of the decoupling of the metallic 5f electron bonding that occurs during hydriding; the C15 phases contain two kinds of Pa atoms-the one sublattice being still fully f-bonded and the other magnetic. This is a unique situation in solid state physics which defies a valence description. A similar situation obtains for A15 β - UH 3 structure. The parent metals themselves exhibit electronegativities not unlike those of the mid-3d transition metals (e.g., Fe) because the valence electrons re tied up in metallic bonding. However, under the driving force for hydriding, the lattices can open up, decoupling the f-bonding and inducing magnetism. The systems then aggressively form very stable hydrides typical of highly-electropositive metals. Beyond uranium the trivalent metallic state is favored and rare-earth-like hydrides are found for Np + H and Pu + H. Nevertheless, the solid-state and transport properties are markedly different than for the rare-earth hydrides, showing that the latent influence of the 5f electrons is still strong

  9. Electronic structure of the actinide-Rh3 systems and the 5f localization in UPd3

    DEFF Research Database (Denmark)

    Eriksson, Olle; Johansson, Börje; Brooks, M. S. S.

    1989-01-01

    We present electronic-structure calculations for the isostructural (AuCu3-structure) series of intermetallic compounds ARh3 (A=Ac, Th, Pa, U, Np, Pu, Am, and Cm). The calculations were performed using both the scalar relativistic and the fully relativistic linear muffin-tin orbital (LMTO) method........ The localization of the 5f electrons in UPd3 as opposed to the itinerant 5f behavior for the earlier compounds (UMo3, UTc3 , URu3, and URh3) is explained in terms of the variation of the hybridization between 5f and ligand 4d states through the series....

  10. Unexpected covalency from actinide 5f orbital interactions (An = Th, U, Np, Pu) determined from chlorine K-edge X-ray absorption spectroscopy and electronic structure theory

    International Nuclear Information System (INIS)

    Clark, D.L.; Batista, E.R.; Boland, K.S.

    2010-01-01

    We have employed Cl K-edge XAS and multiple levels of sophisticated electronic structure calculations on a series of simple octahedral light actinide (Th, U, Np, Pu) chloride salts, AnCl 6 n- in order to assess the relative roles of the valence 5f and 6d orbitals in chemical bonding. Chlorine K-edge X-ray absorption spectroscopy on AnCl 6 n- (An = Th, U, Np, Pu) systems indicates the presence of covalent interactions between both Cl 3p and An 5f and 6d orbitals, with the relative contributions changing across the series. Electronic structure calculations indicate the predominant covalent interactions are expected to occur through An-Cl bonding via t 1u and t 2u interactions with the An 5f orbitals, and through t 2g and e g interactions with An 6d orbitals. For the Cl K-edge data therefore, we expect bound state transitions from Cl 1s → e g (σ), t 2g (π), and t 1u (σ + π) orbitals. Qualitatively, the Cl K-edge data fulfills these expectations

  11. 5f state interaction with inner coordination sphere ligands: einsteinium 3+ ion fluorescence in aqueous and organic phases

    International Nuclear Information System (INIS)

    Beitz, J.V.; Wester, D.W.; Williams, C.W.

    1983-01-01

    The interaction between 5f electron states of einsteinium 3+ ion and coordinated ligands in solution has been probed using laser-induced fluorescence. Aquo einsteinium 3+ ion was observed to fluoresce from its first excited J = 5 state in a broad-band peaking at 9260 wavenumbers. The observed fluorescence lifetimes were 1.05 microseconds and 2.78 microseconds in H 2 O and D 2 O (99+ % D atom), respectively. The non-radiative decay rates derived from the lifetime data are compared with previously reported data for Cm, Sm, Eu, Tb, and Dy aquo 3+ ions. The 5f actinide states exhibit substantially greater non-radiative decay rates than do lanthanide 4f states of similar energy gap. This provides evidence that actinide 5f electrons interact more strongly with their inner coordination sphere than do lanthanide ion 4f electrons. The fluorescence lifetime of einsteinium 3+ ion complexed with 1 formal di(2-ethylhexyl)orthophosphoric acid in h-heptane was 2.34 microseconds. 3 figures, 1 table

  12. Actinides

    International Nuclear Information System (INIS)

    Martinot, L.; Fuger, J.

    1985-01-01

    The oxidation behavior of the actinides is explained on the basis of their electronic structure. The actinide elements, actinium, thorium, protactinium, uranium, neptunium, plutonium, americium, curium, berkelium, californium, einsteinium, fermium, mendelevium, nobelium, and laurencium are included. For all except the last three elements, the points of discussion are oxidation states, Gibbs energies and potentials, and potential diagram for the element in acid solution; and thermodynamic properties of these same elements are tabulated. References are cited following discussion of each element with a total of 97 references being cited. 13 tables

  13. Ground-state electronic structure of actinide monocarbides and mononitrides

    DEFF Research Database (Denmark)

    Petit, Leon; Svane, Axel; Szotek, Z.

    2009-01-01

    The self-interaction corrected local spin-density approximation is used to investigate the ground-state valency configuration of the actinide ions in the actinide monocarbides, AC (A=U,Np,Pu,Am,Cm), and the actinide mononitrides, AN. The electronic structure is characterized by a gradually increa...

  14. f-state luminescence of lanthanide and actinide ions in solution

    International Nuclear Information System (INIS)

    Beitz, J.V.

    1993-01-01

    Detailed studies of the luminescence of aquated Am 3+ are presented in the context of prior lanthanide and actinide ion work. The luminescing state of aquated Am 3+ is confirmed to be 5 D l based on observed emission and excitation spectra. The luminescence lifetime of Am 3+ in H 2 O solution is (22 ± 3) ns and (155 ± 4) ns in D 2 O solution at 295 K. Judd-Ofelt transition intensity theory qualitatively describes the observed Am 3+ relative integrated fluorescence intensities. Recent luminescence studies on complexed trivalent f-element ions in solution are reviewed as to the similarities and differences between lanthanide ion 4f state and actinide ion 5f state properties

  15. Gyromagnetic factors for high spin states in the actinides

    International Nuclear Information System (INIS)

    Ring, P.

    1984-01-01

    The cranked Hartree-Fock-Bogoliubov theory was used for a systematic investigation of gyromagnetic factors in the yrast states of even-even actinide nuclei. The theory used was the most simplified version with fixed deformation and gap parameters, that is, so-called rotating shell model. The gyromagnetic factor g and the contribution gsub(p) and gsub(n) were obtained for a large number of nuclei in the actinide region. The aligned angular momenta for protons and for neutrons are shown in the same actinide region. The general behaviour of g-factor was able to be understood in terms of simple rules: (i) For fixed proton number, neutron alignment becomes more difficult with increasing the neutron number, and vice versa. (ii) A sudden neutron alignment was observed for N=140 and N=146, and a sudden proton alignment was also observed for Z=94. The alignment between these critical numbers was smooth. The pattern obtained for the values of the aligned angular momentum was clearly reflected to the g-factor, and it provided an excellent tool to study the structure of level in the high spin region. (Asami, T.)

  16. Solid-state actinide acid phosphites from phosphorous acid melts

    International Nuclear Information System (INIS)

    Oh, George N.; Burns, Peter C.

    2014-01-01

    The reaction of UO 3 and H 3 PO 3 at 100 °C and subsequent reaction with dimethylformamide (DMF) produces crystals of the compound (NH 2 (CH 3 ) 2 )[UO 2 (HPO 2 OH)(HPO 3 )]. This compound crystallizes in space group P2 1 /n and consists of layers of uranyl pentagonal bipyramids that share equatorial vertices with phosphite units, separated by dimethylammonium. In contrast, the reaction of phosphorous acid and actinide oxides at 210 °C produces a viscous syrup. Subsequent dilution in solvents and use of standard solution-state methods results in the crystallization of two polymorphs of the actinide acid phosphites An(HPO 2 OH) 4 (An=U, Th) and of the mixed acid phosphite–phosphite U(HPO 3 )(HPO 2 OH) 2 (H 2 O)·2(H 2 O). α- and β-An(HPO 2 OH) 4 crystallize in space groups C2/c and P2 1 /n, respectively, and comprise a three-dimensional network of An 4+ cations in square antiprismatic coordination corner-sharing with protonated phosphite units, whereas U(HPO 3 )(HPO 2 OH) 2 (H 2 O) 2 ·(H 2 O) crystallizes in a layered structure in space group Pbca that is composed of An 4+ cations in square antiprismatic coordination corner-sharing with protonated phosphites and water ligands. We discuss our findings in using solid inorganic reagents to produce a solution-workable precursor from which solid-state compounds can be crystallized. - Graphical abstract: Reaction of UO 3 and H 3 PO 3 at 100 °C and subsequent reaction with DMF produces crystals of (NH 2 (CH 3 ) 2 )[UO 2 (HPO 2 OH)(HPO 3 )] with a layered structure. Reaction of phosphorous acid and actinide oxides at 210 °C produces a viscous syrup and further solution-state reactions result in the crystallization of the actinide acid phosphites An(HPO 2 OH) 4 (An=U, Th), with a three-dimensional network structure, and the mixed acid phosphite–phosphite U(HPO 3 )(HPO 2 OH) 2 (H 2 O) 2 ·(H 2 O) with a layered structure. - Highlights: • U(VI), U(IV) and Th(IV) phosphites were synthesized by solution-state

  17. Protactinium and the intersection of actinide and transition metal chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Richard E.; De Sio, Stephanie; Vallet, Valérie

    2018-02-12

    The role of the 5f and 6d orbitals in the chemistry of the actinide elements has been of considerable interest since their discovery and synthesis. Relativistic effects cause the energetics of the 5f and 6d orbitals to change as the actinide series is traversed left to right imparting a rich and complex chemistry. The 5f and 6d atomic states cross in energy at protactinium (Pa), making it a potential intersection between transition metal and actinide chemistries. Herein, we report the synthesis of a Pa-peroxo cluster, A(6)(Pa4O(O-2)(6)F-12) [A = Rb, Cs, (CH3)(4)N], formed in pursuit of an actinide polyoxometalate. Quantum chemical calculations at the density functional theory level demonstrate equal 5f and 6d orbital participation in the chemistry of Pa and increasing 5f orbital participation for the heavier actinides. Periodic changes in orbital character to the bonding in the early actinides highlights the influence of the 5f orbitals in their reactivity and chemical structure.

  18. Stabilization of actinides and lanthanides in unusually high oxidation states

    International Nuclear Information System (INIS)

    Eller, P.G.; Penneman, R.A.

    1986-01-01

    Chemical environments can be chosen which stabilize actinides and lanthanides in unusually high or low oxidation states and in unusual coordination. In many cases, one can rationalize the observed species as resulting from strong charge/size influences provided by specific sites in host lattices (e.g., Tb(IV) in BaTbO 3 or Am(IV) in polytungstate anions). In other cases, the unusual species can be considered from an acid-base viewpoint (e.g., U(III) in AsF 5 /HF solution or Pu(VII) in Li 5 PuO 6 ). In still other cases, an interplay of steric and redox effects can lead to interesting comparisons (e.g., instability of double fluoride salts of Pu(V) and Pu(VI) relative to U, Np, and Am analogues). Generalized ways to rationalize compounds containing actinides and lanthanides in unusual valences (particularly high valences), including the above and numerous other examples, will form the focus of this paper. Recently developed methods for synthesizing high valent f-element fluorides using superoxidizers and superacids at low temperatures will also be described. 65 refs., 8 figs., 9 tabs

  19. Spin and orbital moments in actinide compounds

    DEFF Research Database (Denmark)

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

    1991-01-01

    The extended spatial distribution of both the transition-metal 3d electrons and the actinide 5f electrons results in a strong interaction between these electron states when the relevant elements are alloyed. A particular interesting feature of this hybridization, which is predicted by single...... 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...

  20. Solid state physics and actinide spectroscopy with ThBr4 and ThCl4

    International Nuclear Information System (INIS)

    Genet, M.

    1984-01-01

    From the solid state physics to the optical spectroscopy of 5 f elements, we have described in details how ThBr 4 and ThCl 4 are acting an important role in the applied and basic research field. The possible applications are based on the scintillation properties of these crystals while the fundamental aspect is related to their special incommensurate structure which modulates the host properties of these matrices at low temperature. This very small perturbation of bromine atom positions have optical consequences on the absorption and emission of the actinide studied ions which are interpreted in function of the modulated structure parameters determined by inelastic and elastic neutron scattering and by Raman spectroscopy. The structural model proposed shows, for the first time, how the optical properties of the investigated ion are influenced by the sinusoidal displacements of the bromine atoms, leading to an energy continuum in the absorption and reducing the site symmetry from Dsub(2d) to a multisite of D 2 symmetry

  1. Actinides-1981

    International Nuclear Information System (INIS)

    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

  2. Actinides-1981

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. Some activities in the United States concerning the physics aspects of actinide waste recycling

    International Nuclear Information System (INIS)

    Raman, S.

    1976-01-01

    This review paper briefly discusses the reactor types being considered in the United States for the purpose of actinide waste recycling. The reactor types include thermal reactors operating on the 3.3% 235 U- 238 U and the 233 U- 232 Th fuel cycles, liquid metal fast breeder reactors, reactors fueled entirely by actinide wastes, gaseous fuel reactors and fusion reactors. This paper also discusses cross section measurements in progress or planned toward providing basic data for testing the recycle concept. (author)

  4. Some activities in the United States concerning the physics aspects of actinide waste recycling

    International Nuclear Information System (INIS)

    Raman, S.

    1975-01-01

    Reactor types being considered in the United States for the purpose of actinide waste recycling are discussed briefly. The reactor types include thermal reactors operating on the 3.3 percent 235 U-- 238 U and the 233 U-- 232 Th fuel cycles, liquid metal fast breeder reactors, reactors fueled entirely by actinide wastes, gaseous fuel reactors, and fusion reactors. Cross section measurements in progress or planned toward providing basic data for testing the recycle concept are also discussed

  5. X-ray spectral study of the Th6p,5f electron states in ThO2 and ThF4

    International Nuclear Information System (INIS)

    Teterin, Y.A.; Nikitin, A.S.; Teterin, A.Y.; Ivanov, K.E.; Utkin, I.O.; Nerehov, V.A.; Ryzhkov, M.V.; Vukchevich, I.J.

    2002-01-01

    The study of the Th6p,5f electron states in Th, ThO 2 and ThF was carried out on the basis of the X-ray photoelectron fine spectral structure parameters in the binding energy range of 0-∼ 1000 eV, X-ray O 4,5 (Th) emission spectra of the shallow (0-∼50 eV) electrons and results of theoretical calculations. As a result, despite the absence of the Th5f electrons in thorium atoms, the Th5f atomic orbitals were established to participate in the formation of molecular orbitals in thorium dioxide and tetrafluoride. In the MO LCAO approximation this allowed to suggest the possible existence of filled Th5f electronic states in thorium compounds. On the basis of the X-ray O 4,5 (Th) emission spectral structure parameters the effective formation of the inner valence molecular orbitals in the studied compounds was confirmed. (authors)

  6. Phase Behavior and Equations of State of the Actinide Oxides

    Science.gov (United States)

    Chidester, B.; Pardo, O. S.; Panero, W. R.; Fischer, R. A.; Thompson, E. C.; Heinz, D. L.; Prescher, C.; Prakapenka, V. B.; Campbell, A.

    2017-12-01

    The distribution of the long-lived heat-producing actinide elements U and Th in the deep Earth has important implications for the dynamics of the mantle and possibly the energy budget of Earth's core. The low shear velocities of the Large Low-Shear Velocity Provinces (LLSVPs) on the core-mantle boundary suggests that these regions are at least partially molten and may contain concentrated amounts of the radioactive elements, as well as other large cations such as the rare Earth elements. As such, by exploring the phase behavior of actinide-bearing minerals at extreme conditions, some insight into the mineralogy, formation, and geochemical and geodynamical effects of these regions can be gained. We have performed in situ high-pressure, high-temperature synchrotron X-ray diffraction experiments and calculations on two actinide oxide materials, UO2 and ThO2, to determine their phase behavior at the extreme conditions of the lower mantle. Experiments on ThO2 reached 60 GPa and 2500 K, and experiments on UO2 reached 95 GPa and 2500 K. We find that ThO2 exists in the fluorite-type structure to 20 GPa at high temperatures, at which point it transforms to the high-pressure cotunnite-type structure and remains thus up to 60 GPa. At room temperature, an anomalous expansion of the fluorite structure is observed prior to the transition, and may signal anion sub-lattice disorder. Similarly, UO2 exists in the fluorite-type structure at ambient conditions and up to 28 GPa at high temperatures. Above these pressures, we have observed a previously unidentified phase of UO2 with a tetragonal structure as the lower-temperature phase and the cotunnite-type phase at higher temperatures. Above 78 GPa, UO2 undergoes another transition or possible dissociation into two separate oxide phases. These phase diagrams suggest that the actinides could exist as oxides in solid solution with other analogous phases (e.g. ZrO2) in the cotunnite-type structure throughout much of Earth's lower mantle.

  7. Moessbauer effect studies with actinides

    International Nuclear Information System (INIS)

    Stone, J.A.

    1966-01-01

    Moessbauer resonance studies in the actinide elements offer a new technique for measuring solid-state properties to a region of the periodic chart where such information is relatively sparse. It is well known that the actinides, the elements with atomic numbers from 90 to 103, form a transition series due to filling of the 5f electron shell, analogous to the rare-earth series in which the 4f shell is filled. Like the rare earths, the actinide metals and compounds are expected to exhibit a variety of interesting magnetic properties, but, unlike the rare earths, there have been few studies of the magnetic behaviour of actinides, and these properties are largely unknown. The chemical properties of the actinides have been studied somewhat more extensively, and, in contrast to the rare earths, form a multiplicity of stable valence states, especially in the lighter members of the series. It is just these properties, magnetic and chemical, for which the Moessbauer effect is a valuable probe, sensitive to the magnetic and electric environment of an atom. The rare-earth series has been a particularly fruitful region in terms of the number of elements which have been shown to exhibit the Moessbauer effect, and for this reason the exploitation of the Moessbauer effect to yield new solid-state and chemical information on the rare earths is a highly active field of research today. There is every reason to believe that the actinides can be similarly studied by the Moessbauer effect. 43 refs, 6 figs, 4 tabs

  8. The actinides-a beautiful ending of the Periodic Table

    International Nuclear Information System (INIS)

    Johansson, Boerje; Li, Sa

    2007-01-01

    The 5f elements, actinides, show many properties which have direct correspondence to the 4f transition metals, the lanthanides. The remarkable similarity between the solid state properties of compressed Ce and the actinide metals is pointed out in the present paper. The α-γ transition in Ce is considered as a Mott transition, namely, from delocalized to localized 4f states. An analogous behavior is also found for the actinide series, where the sudden volume increase from Pu to Am can be viewed upon as a Mott transition within the 5f shell as a function of the atomic number Z. On the itinerant side of the Mott transition, the earlier actinides (Pa-Pu) show low symmetry structures at ambient conditions; while across the border, the heavier elements (Am-Cf) present the dhcp structure, an atomic arrangement typical for the trivalent lanthanide elements with localized 4f magnetic moments. The reason for an isostructural Mott transition of the f electron in Ce, as opposed to the much more complicated cases in the actinides, is identified. The strange appearance of the δ-phase (fcc) in the phase diagram of Pu is another consequence of the border line behavior of the 5f electrons. The path leading from δ-Pu to α-Pu is identified

  9. The effect of high pressures on actinide metals

    International Nuclear Information System (INIS)

    Benedict, U.

    1987-01-01

    The solid state properties of the actinides are controlled by the dualism of the localized and itinerant (delocalized) configuration of the 5f electrons. This dualism allows to define two main subgroups. At ambient pressures the first subgroup, of elements with atomic number 91 to 94, is characterized by 5f electrons in an itinerant state and the second subgroup, atomic number 95 to 98, by 5f electrons in a localized state. The latter means that these electrons have well defined energy levels and do not contribute to the metallic bond. The other two subgroups consist of thorium, as a subgroup of its own because its 5f levels are practically unoccupied in the ground state configuration, and of the five heaviest elements with atomic number 99 to 103. The most remarkable effect of pressure on the actinide metals is that due to closer contact between the lattice atoms, localized 5f electrons can become itinerant, hybridise with the conduction electrons and participate in the metallic bond. In this chapter the high-pressure structural behaviour of actinide metals is reviewed. Section 3 gives an introduction into the techniques of generating and measuring pressure and of determining various physical properties of the actinides under pressure and describes a few high-pressure devices and methods. Sections 4 to 7 treat the high-pressure results for each subgroup separately. In section 8 the results of the preceding sections are brought together in a graphical representation which consists of interconnecting binary phase diagrams of neighbouring actinide metals. 155 refs.; 14 figs.; 7 tabs. (H.W.)

  10. Calculated Atomic Volumes of the Actinide Metals

    DEFF Research Database (Denmark)

    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....

  11. The chemistry of the actinide elements. Volume I

    International Nuclear Information System (INIS)

    Katz, J.J.; Seaborg, G.T.; Morss, L.R.

    1986-01-01

    The Chemistry of the Actinide Elements is a comprehensive, contemporary and authoritative exposition of the chemistry and related properties of the 5f series of elements: actinium, thorium, protactinium, uranium and the first eleven. This second edition has been completely restructured and rewritten to incorporate current research in all areas of actinide chemistry and chemical physics. The descriptions of each element include accounts of their history, separation, metallurgy, solid-state chemistry, solution chemistry, thermo-dynamics and kinetics. Additionally, separate chapters on spectroscopy, magnetochemistry, thermodynamics, solids, the metallic state, complex ions and organometallic compounds emphasize the comparative chemistry and unique properties of the actinide series of elements. Comprehensive lists of properties of all actinide compounds and ions in solution are given, and there are special sections on such topics as biochemistry, superconductivity, radioisotope safety, and waste management, as well as discussion of the transactinides and future elements

  12. Influence of microorganisms on the oxidation state distribution of multivalent actinides under anoxic conditions

    International Nuclear Information System (INIS)

    Reed, Donald Timothy; Borkowski, Marian; Lucchini, Jean-Francois; Ams, David; Richmann, M.K.; Khaing, H.; Swanson, J.S.

    2010-01-01

    The fate and potential mobility of multivalent actinides in the subsurface is receiving increased attention as the DOE looks to cleanup the many legacy nuclear waste sites and associated subsurface contamination. Plutonium, uranium and neptunium are the near-surface multivalent contaminants of concern and are also key contaminants for the deep geologic disposal of nuclear waste. Their mobility is highly dependent on their redox distribution at their contamination source as well as along their potential migration pathways. This redox distribution is often controlled, especially in the near-surface where organic/inorganic contaminants often coexist, by the direct and indirect effects of microbial activity. Under anoxic conditions, indirect and direct bioreduction mechanisms exist that promote the prevalence of lower-valent species for multivalent actinides. Oxidation-state-specific biosorption is also an important consideration for long-term migration and can influence oxidation state distribution. Results of ongoing studies to explore and establish the oxidation-state specific interactions of soil bacteria (metal reducers and sulfate reducers) as well as halo-tolerant bacteria and Archaea for uranium, neptunium and plutonium will be presented. Enzymatic reduction is a key process in the bioreduction of plutonium and uranium, but co-enzymatic processes predominate in neptunium systems. Strong sorptive interactions can occur for most actinide oxidation states but are likely a factor in the stabilization of lower-valent species when more than one oxidation state can persist under anaerobic microbiologically-active conditions. These results for microbiologically active systems are interpreted in the context of their overall importance in defining the potential migration of multivalent actinides in the subsurface.

  13. State-of-art technology of fuels for burning minor actinides. An OECD/NEA study

    International Nuclear Information System (INIS)

    Ogawa, Toru; Konings, R.J.M.; Pillon, S.; Schram, R.P.C.; Verwerft, M.; Wallenius, J.

    2005-01-01

    At OECD/NEA, Working Party on Scientific Issues in Partitioning and Transmutation was formed for 2000-2004, which studied the status and trends of scientific issues in Partitioning and Transmutation (P and T). The study included the scientific and technical issues of fuels and materials, which are related to dedicated systems for transmutation. This paper summarizes the state-of-art technology of the fuels for burning minor actinides (neptunium, americium and curium). (author)

  14. Actinides, the narrowwest bands

    International Nuclear Information System (INIS)

    Smith, J.L.; Riseborough, P.S.

    1984-01-01

    A table of elements is shown that demonstrates the crossover from superconductivity to magnetism as well as regions of mixed valence. In particular, the actinides must eventually show 4f-electron like mixed valence, after the 5f-electrons become localized. There also seems to be an adiabatic continuation between heavy fermion and mixed valence behavior

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

    International Nuclear Information System (INIS)

    McKay, H.A.C.; Sowerby, M.G.; Bustraan, M.; Montizaan, J.; Dalen, A. van; Verkerk, B.

    1977-01-01

    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

  16. Orbital effects in actinide systems

    International Nuclear Information System (INIS)

    Lander, G.H.

    1983-01-01

    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

  17. 3 and 4 oxidation state element solubilities in borosilicate glasses. Implement to actinides in nuclear glasses

    International Nuclear Information System (INIS)

    Cachia, J.N.

    2005-12-01

    In order to ensure optimal radionuclides containment, the knowledge of the actinide loading limits in nuclear waste glasses and also the comprehension of the solubilization mechanisms of these elements are essential. A first part of this manuscript deals with the study of the differences in solubility of the tri and tetravalent elements (actinides and surrogates) particularly in function of the melting temperature. The results obtained indicate that trivalent elements (La, Gd, Nd, Am, Cm) exhibit a higher solubility than tetravalent elements (Hf, Th, Pu). Consequently, it was planned to reduce plutonium at the oxidation state (III), the later being essentially tetravalent in borosilicate glasses. An innovating reduction process of multi-valent elements (cerium, plutonium) using silicon nitride has been developed in a second part of this work. Reduced plutonium-bearing glasses synthesized by Si 3 N 4 addition made it possible to double the plutonium solubility from 2 to 4 wt% at 1200 deg C. A structural approach to investigate the differences between tri and tetravalent elements was finally undertaken. These investigations were carried out by X-rays Absorption Spectroscopy (EXAFS) and NMR. Trivalent rare earth and actinide elements seem to behave as network modifiers while tetravalent elements rather present true intermediaries' behaviour. (author)

  18. The actinides

    International Nuclear Information System (INIS)

    Bagnall, K.W.

    1987-01-01

    This chapter of coordination compound chemistry is devoted to the actinides and starts with a general survey. Most of the chapter relates to thorium and uranium but protactinium, neptunium and plutonium are included. There are sections on nitrogen, phosphorus, sulfur, selenium, tellurium and halogen ligands of the metals in their +3, +4, +5 and +6 oxidation states and of the transplutonium elements in their +2, +3, +4, and +5 oxidation states. (UK)

  19. Electrical resistivity of 5 f -electron systems affected by static and dynamic spin disorder

    Science.gov (United States)

    Havela, L.; Paukov, M.; Buturlim, V.; Tkach, I.; Drozdenko, D.; Cieslar, M.; Mašková, S.; Dopita, M.; Matěj, Z.

    2017-06-01

    Metallic 5 f materials have very strong coupling of magnetic moments and electrons mediating electrical conduction. It is caused by strong spin-orbit interaction, coming with high atomic number Z , together with involvement of the 5 f states in metallic bonding. We have used the recently discovered class of uranium (ultra)nanocrystalline hydrides, which are ferromagnets with high ordering temperature, to disentangle the origin of negative temperature coefficient of electrical resistivity. In general, the phenomenon of electrical resistivity decreasing with increasing temperature in metals can have several reasons. The magnetoresistivity study of these hydrides reveals that quantum effects related to spin-disorder scattering can explain the resistivity behavior of a broad class of actinide compounds.

  20. Electronic structure of free and doped actinides: N and Z dependences of energy levels and electronic structure parameters

    International Nuclear Information System (INIS)

    Kulagin, N.

    2005-01-01

    Theoretical study of electronic structure of antinide ions and its dependence on N and Z are presented in this paper. The main 5f N and excited 5f N n'l' N' configurations of actinides have been studied using Hartree-Fock-Pauli approximation. Results of calculations of radial integrals and the energy of X-ray lines for all 5f ions with electronic state AC +1 -AC +4 show approximate dependence on N and Z. A square of N and cubic of Z are ewalized for the primary electronic parameters of the actinides. Theoretical values of radial integrals for free actinides and for ions in a cluster AC +n :[L] k are compared, too

  1. Proceedings of the symposium Actinides 2006 - Basic Science, Applications and Technology

    International Nuclear Information System (INIS)

    Blobaum, Kerri J.M.; Chandler, Elaine A.; Havela, Ladislav; Maple, M. Brian; Neu, Mary P.

    2007-01-01

    These proceedings from the September 2006 symposium includes papers presented on experimental and modeling work with the intention of broadening understanding of the field of actinide research. Actinides have gained attention recently because of their roles in the threat of nuclear terrorism (e.g., 'dirty bombs') and the use of nuclear power to offset fossil fuel consumption. Actinide science is the study of the elements with atomic numbers in the range of 90 to 103, which includes uranium and plutonium. Beyond the well-known nuclear reactions of these heavy radioactive metals, the large electron clouds with 5f electrons in the outer shell yield fascinating and complex chemistries, crystal structures, and physical properties. Traditionally, actinide research has been divided among three scientific disciplines: chemistry (nuclear chemistry and radiochemistry); physics (condensed matter physics and electronic structure); and materials science (metallurgy). Modern actinide research, however, has become an interdisciplinary blend of these traditional fields, and it also incorporates developing fields such as environmental chemistry and superconductivity. Improved scientific understanding of actinides is needed for development of materials for actinide detection and nuclear fuels, and for safer management of nuclear waste. Recently, there has been a resurgence of actinide science at national laboratories and universities. The current multidisciplinary approach to actinide science lays the groundwork for understanding the connection between the 5f electronic structure and observed chemical reactions and physical properties such as structural phase transformations and novel ground states. This work provides many opportunities for new researchers in actinide science. These proceedings gather 25 selected papers among the 53 presentations given at this symposium

  2. Delocalization and occupancy effects of 5f orbitals in plutonium intermetallics using L3-edge resonant X-ray emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Booth, C. H.; Medling, S. A.; Jiang, Yu; Bauer, E. D.; Tobash, P. H.; Mitchell, J. N.; Veirs, D. K.; Wall, M. A.; Allen, P. G.; Kas, J. J.; Sokaras, D.; Nordlund, D.; Weng, T. -C.

    2014-06-24

    Although actinide (An) L3 -edge X-ray absorption near-edge structure (XANES) spectroscopy has been very effective in determining An oxidation states in insulating, ionically bonded materials, such as in certain coordination compounds and mineral systems, the technique fails in systems featuring more delocalized 5f orbitals, especially in metals. Recently, actinide L3-edge resonant X-ray emission spec- troscopy (RXES) has been shown to be an effective alternative. This technique is further demonstrated here using a parameterized partial unoccupied density of states method to quantify both occupancy and delocalization of the 5f orbital in ?-Pu, ?-Pu, PuCoGa5 , PuCoIn5 , and PuSb2. These new results, supported by FEFF calculations, highlight the effects of strong correlations on RXES spectra and the technique?s ability to differentiate between f-orbital occupation and delocalization.

  3. In-beam study of the rotational states in actinides after alpha-induced nuclear reactions

    International Nuclear Information System (INIS)

    Hardt, K.

    1983-01-01

    In the experiments described in this thesis the ground state rotational bands of a whole series of actinide isotopes has been studied by means of α-induced nuclear reactions. The rotational bands studied in the even isotopes could be identified up to a spin of about 16 (h/2π). With this data it was now possible to establish a broad systematic of the rotational energies up to relatively high angular momenta. Also in the odd isotopes 233 U and 239 Pu it was possible to follow the ground state rotational bands up to higher spins and to compare them with predictions of the rotational model. By means of the (α,α'2n) reaction the nuclei 230 Th and especially 228 Th could by populated. (orig./HSI) [de

  4. Low-temperature synthesis of actinide tetraborides by solid-state metathesis reactions

    Science.gov (United States)

    Lupinetti, Anthony J [Los Alamos, NM; Garcia, Eduardo [Los Alamos, NM; Abney, Kent D [Los Alamos, NM

    2004-12-14

    The synthesis of actinide tetraborides including uranium tetraboride (UB.sub.4), plutonium tetraboride (PuB.sub.4) and thorium tetraboride (ThB.sub.4) by a solid-state metathesis reaction are demonstrated. The present method significantly lowers the temperature required to .ltoreq.850.degree. C. As an example, when UCl.sub.4 is reacted with an excess of MgB.sub.2, at 850.degree. C., crystalline UB.sub.4 is formed. Powder X-ray diffraction and ICP-AES data support the reduction of UCl.sub.3 as the initial step in the reaction. The UB.sub.4 product is purified by washing water and drying.

  5. Atomistic modeling of the solid-state chemistry of actinide materials

    Science.gov (United States)

    Shuller, Lindsay C.

    Materials that incorporate actinides are critical to the nuclear fuel cycle, either as nuclear fuels or nuclear waste forms. In this thesis, I examine four materials: i) ThO2-UO2 solid solutions, ii) binary ThO2-CeO2-ZrO2 solid solutions, iii) Np-doped studtite, iv) Np-doped boltwoodite. Computational methods, particularly density functional theory (DFT) calculations and Monte-Carlo (MC) simulations, are used to determine the energetics and structures of these actinide-bearing materials. The solid-solution behavior of nuclear fuels and nuclear waste forms indicate the thermodynamic stability of the material, which is important for understanding the in-reactor fuel properties and long-term stability of used fuel. The ThxU1-xO2 and ThxCe 1-xO2 binaries are almost completely miscible; however, DeltaGmix reveals a small tendency for the systems to exsolve (e.g., DeltaEexsoln(Th xU1-xO2) = 0.13 kJ/(mol cations) at 750 K). Kinetic hindrances (e.g., interfacial energy) may inhibit exsolution, especially at the low temperatures necessary to stabilize the nanoscale exsolution lamellae observed in the ThxU1-xO2 and Ce xZr1-xO2 binaries. Miscibility in the Zr-bearing binaries is limited. At 1400 °C, only 3.6 and 0.09 mol% ZrO2 is miscible in CeO2 and ThO2, respectively. The incorporation of minor amounts of Np5+,6+ into uranium alteration phases, e.g., studtite [UO2O2 (H2O)4] or boltwoodite [K(UO2)(SiO 3OH)(H2O)1.5] , may limit the mobility of aqueous neptunyl complexes released from oxidized nuclear fuels. Np6+-incorporation into studtite requires less energy than Np5+-incorporation (e.g., with source/sink = Np2O5/UO 3 DeltaEincorp(Np6+) = 0.42 eV and DeltaEincorp(Np5+) = 1.12 eV). In addition, Np6+ is completely miscible in studtite at room temperature with respect to a hypothetical Np6+-studtite. Electronic structure calculations provide insight into Np-bonding in studtite. The Np 5f orbitals are within the band gap of studtite, resulting in the narrowing of the band gap

  6. Research in actinide chemistry

    International Nuclear Information System (INIS)

    Choppin, G.R.

    1993-01-01

    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 - , CO 3 2- , PO 4 3- , humates). The research undertakes fundamental studies of actinide complexes which can increase understanding of the environmental behavior of these elements

  7. Band structures of 4f and 5f materials studied by angle-resolved photoelectron spectroscopy.

    Science.gov (United States)

    Fujimori, Shin-ichi

    2016-04-20

    Recent remarkable progress in angle-resolved photoelectron spectroscopy (ARPES) has enabled the direct observation of the band structures of 4f and 5f materials. In particular, ARPES with various light sources such as lasers (hν ~ 7 eV) or high-energy synchrotron radiations (hν >/~ 400 eV) has shed light on the bulk band structures of strongly correlated materials with energy scales of a few millielectronvolts to several electronvolts. The purpose of this paper is to summarize the behaviors of 4f and 5f band structures of various rare-earth and actinide materials observed by modern ARPES techniques, and understand how they can be described using various theoretical frameworks. For 4f-electron materials, ARPES studies of CeMIn5(M = Rh, Ir, and Co) and YbRh2Si2 with various incident photon energies are summarized. We demonstrate that their 4f electronic structures are essentially described within the framework of the periodic Anderson model, and that the band-structure calculation based on the local density approximation cannot explain their low-energy electronic structures. Meanwhile, electronic structures of 5f materials exhibit wide varieties ranging from itinerant to localized states. For itinerant U5f compounds such as UFeGa5, their electronic structures can be well-described by the band-structure calculation assuming that all U5f electrons are itinerant. In contrast, the band structures of localized U5f compounds such as UPd3 and UO2 are essentially explained by the localized model that treats U5f electrons as localized core states. In regards to heavy fermion U-based compounds such as the hidden-order compound URu2Si2, their electronic structures exhibit complex behaviors. Their overall band structures are generally well-explained by the band-structure calculation, whereas the states in the vicinity of EF show some deviations due to electron correlation effects. Furthermore, the electronic structures of URu2Si2 in the paramagnetic and hidden-order phases are

  8. Octupole correlations in positive-parity states of rare-earth and actinide nuclei

    Directory of Open Access Journals (Sweden)

    Spieker M.

    2015-01-01

    Full Text Available In this contribution, further evidence of the importance of multiphonon-octupole excitations to describe experimental data in the rare earths and actinides will be presented. First, new results of a (p, t experiment at the Q3D magnetic spectrograph in Munich will be discussed, which was performed to selectively excite Jπ = 0+ states in 240Pu. spdf interacting boson model (IBM calculations suggest that the previously proposed double-octupole phonon nature of the Jπ = 0+2 state is not in conflict with its strong (p, t population. Second, the framework of the IBM has been adopted for the description of experimental observables related to octupole excitations in the rare earths. Here, the IBM is able to describe the signature splitting for positiveand negative-parity states when multi-dipole and multi-octupole bosons are included. The present study might support the idea of octupole-phonon condensation at intermediate spin (Jπ = 10+ leading to the change in yrast structure observed in 146Nd.

  9. High orbital angular momentum states in H2 and D2. II. The 6h--5g and 6g--5f transitions

    International Nuclear Information System (INIS)

    Jungen, C.; Dabrowski, I.; Herzberg, G.; Kendall, D.J.W.

    1989-01-01

    A group of lines accompanying the first line of the Pfund series of the H atom has been observed by Fourier transform infrared spectrometry. The lines are due to transitions in molecular hydrogen of a nonpenetrating Rydberg electron possessing a high-orbital angular momentum, which is coupled only loosely to the vibrations and rotations of the H + 2 core. Lines belonging to the 6h--5g and 6g--5f (v=0--3) transitions of H 2 have been identified. The identifications are based on a calculation of the spectrum from first principles by multichannel quantum defect theory. The interaction between the nonpenetrating electron and the core was evaluated in terms of the permanent and induced molecular moments of H + 2 as calculated by Bishop and collaborators. The analogous transitions in D 2 have also been observed and assigned

  10. In-beam studies of high-spin states of actinide nuclei

    International Nuclear Information System (INIS)

    Stoyer, M.A.; California Univ., Berkeley, CA

    1990-01-01

    High-spin states in the actinides have been studied using Coulomb- excitation, inelastic excitation reactions, and one-neutron transfer reactions. Experimental data are presented for states in 232 U, 233 U, 234 U, 235 U, 238 Pu and 239 Pu from a variety of reactions. Energy levels, moments-of-inertia, aligned angular momentum, Routhians, gamma-ray intensities, and cross-sections are presented for most cases. Additional spectroscopic information (magnetic moments, M 1 /E 2 mixing ratios, and g-factors) is presented for 233 U. One- and two-neutron transfer reaction mechanisms and the possibility of band crossings (backbending) are discussed. A discussion of odd-A band fitting and Cranking calculations is presented to aid in the interpretation of rotational energy levels and alignment. In addition, several theoretical calculations of rotational populations for inelastic excitation and neutron transfer are compared to the data. Intratheory comparisons between the Sudden Approximation, Semi-Classical, and Alder-Winther-DeBoer methods are made. In connection with the theory development, the possible signature for the nuclear SQUID effect is discussed. 98 refs., 61 figs., 21 tabs

  11. Handbook on the physics and chemistry of the actinides. V. 3

    International Nuclear Information System (INIS)

    Freeman, A.J.; Keller, C.

    1985-01-01

    It is the purpose of the Handbook to describe in detail the present understanding of the actinides by means of comprehensive, critical, broad and up to date reviews covering both physics and chemistry of these exotic elements. Volume 3 is the first of two volumes to cover the more chemical, physico-chemical, structural and environmental aspects of the actinide elements. Leading scientists from Europe, USA and P.R. China present critical reviews on important aspects of the behaviour of this radioactive group of elements. In contrast to most other elements radioactivity has, to a degree, a profound influence on the chemical behaviour of the actinides. The unusual behaviour of the 5f-elements - delocalization of the electrons for the light actinides versus localization for the heavier ones - makes them an outstanding tool for the scientist, which can be seen by the variety of oxidation states ranging from +1 to +7. Special laboratory techniques must be developed to deal with the problem of the transcurium elements only being available in small amounts (nanograms to micrograms) or only in the tracer scale. Special emphasis is also placed on the fate of actinides released in the environment, e.g. their reaction to carbonate and organic complexing agents in aquatic systems. In contrast to volumes 1 and 2 which deal mainly with the less radioactive actinides, this volume and the forthcoming volume 4 cover all actinides, in particular those which can be prepared in weighable quantities (up to fermium, element 100). refs.; figs.; tabs

  12. Complexation and extraction of series 4f, 5f and 4d ions by dialkyldithiophosphoric acids

    International Nuclear Information System (INIS)

    Fitoussi, Richard.

    1982-04-01

    A study was carried out on the complexing and extracting properties of various dialkyldithiophosphoric acids towards ions of the 4f, 5f and 4d series. Sulphurated donors complex and extract ions of the 4f and 5f series less strongly than their oxygenated homologues. However the affinity of trivalent actinide ions for dialkythiophosphate ions is shown to be greater than that of lanthanides. The conditions of ruthenium extraction from nitric acid are defined [fr

  13. Relativistic band-structure calculations for electronic properties of actinide dioxides

    International Nuclear Information System (INIS)

    Maehira, Takahiro; Hotta, Takashi

    2007-01-01

    Energy band structures of actinide dioxides AnO 2 (An=Th, U, Np, and Pu) are investigated by a relativistic linear augmented-plane-wave method with the exchange-correlation potential in a local density approximation (LDA). It is found in common that the energy bands in the vicinity of the Fermi level are mainly due to the hybridization between actinide 5f and oxygen 2p electrons. By focusing on the crystalline electric field states, we point out the problem in the application of the LDA to AnO 2

  14. Energy level schemes of f{sup N} electronic configurations for the di-, tri-, and tetravalent lanthanides and actinides in a free state

    Energy Technology Data Exchange (ETDEWEB)

    Ma, C.-G. [College of Sciences, Chongqing University of Posts and Telecommunications, Chongqing 400065 (China); Brik, M.G., E-mail: mikhail.brik@ut.ee [College of Sciences, Chongqing University of Posts and Telecommunications, Chongqing 400065 (China); Institute of Physics, University of Tartu, Ravila 14C, Tartu 50411 (Estonia); Institute of Physics, Jan Dlugosz University, Armii Krajowej 13/15, PL-42200 Czestochowa (Poland); Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw (Poland); Liu, D.-X.; Feng, B.; Tian, Ya [College of Sciences, Chongqing University of Posts and Telecommunications, Chongqing 400065 (China); Suchocki, A. [Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw (Poland)

    2016-02-15

    The energy level diagrams are theoretically constructed for the di-, tri-, tetravalent lanthanide and actinide ions, using the Hartree–Fock calculated parameters of the Coulomb and spin–orbit interactions within f{sup N} (N=1…13) electron configurations. These diagrams are analogous to Dieke's diagram, which was obtained experimentally. They can be used for an analysis of the optical spectra of all considered groups of ions in various environments. Systematic variation of some prominent energy levels (especially those ones with a potential for emission transitions) along the isoelectronic 4f/5f ions is considered. - Highlights: • Energy level schemes for di-, tri, tetravalent lanthanides/actinides are calculated. • Systematic variation of the characteristic energy levels across the series is considered. • Potentially interesting emission transitions are identified.

  15. Equilibrium constants in aqueous lanthanide and actinide chemistry from time-resolved fluorescence spectroscopy: The role of ground and excited state reactions

    International Nuclear Information System (INIS)

    Billard, I.; Luetzenkirchen, K.

    2003-01-01

    Equilibrium constants for aqueous reactions between lanthanide or actinide ions and (in-) organic ligands contain important information for various radiochemical problems, such as nuclear reprocessing or the migration of radioelements in the geosphere. We study the conditions required to determine equilibrium constants by time-resolved fluorescence spectroscopy measurements. Based on a simulation study it is shown that the possibility to determine equilibrium constants depends upon the reaction rates in the photoexcited states of the lanthanide or actinide ions. (orig.)

  16. General regularity of the oxidation potential variations and high oxidation states in the second half of the actinide series

    International Nuclear Information System (INIS)

    Spitsyn, V.I.; Vokhmin, V.G.; Ionova, G.V.; Pershina, V.G.

    1984-01-01

    Oxidation potentials (OP) PHI(4/3), PHI(5/3), PHI(6/3), PHI(5/4) and PHI(6/5) are calculated for the members of the actinide series. A semiemperic relation combining OP with explicit terms for ground level energies of actinide ions in Russell-Saunders approximation as well as known values of formal OP relative to the normal hydrogen electrode potential are used as an extrapolation function. It is shown that an increase of PHI(4/3) OP which occurs after Bsub(k) explains a low stability of the oxidation state 4 in solutions for actinides of the second half of the series. PHI(5/3) and PHI(5/4) OP in the section starting with Cm have the minimum at Cf. PHI(6/3) OP for Cm, Bk, Cf and Es are practically the same but for Cm, Bk and Es they are smaller than PHI(5/3) OP. A principle possibility of Bk(6), Cf(6) and Es(6) preparation is shown

  17. Solid state synthesis and sintering of monazite-type ceramics: application to minor actinides conditioning

    International Nuclear Information System (INIS)

    Bregiroux, D.

    2005-11-01

    In the framework of the French law of 1991 concerning the nuclear waste management, several studies are undertaken to develop specific crystalline conditioning matrices. Monazite, a rare earth (TR 3+ ) orthophosphate with a general formula TR 3+ PO 4 , is a natural mineral containing significant amount of thorium and uranium. Monazite has been proposed as a host matrix for the minor actinides (Np, Am and Cm) specific conditioning, thanks to its high resistance to self irradiation and its low solubility. Its is now of prime importance to check the conservation of these properties on synthesized materials, which implies to master all the stages of the elaboration process, from the powder synthesis to the sintering of controlled microstructure pellets. This work can be divided into two main parts: The first part deals with the synthesis by high temperature solid state route of TR 3+ PO 4 powders (with TR 3+ = La 3+ to Gd 3+ , Pu 3+ and Am 3+ ). The chemical reactions occurring during the firing of starting reagents are described in the case of monazite with only one or several cations. From these results, a protocol of synthesis is described. The incorporation of tetravalent cations (Ce 4+ , U 4+ , Pu 4+ ) in the monazite structure was also studied. The second part of the present work deals with the elaboration of controlled density and microstructure monazite pellets and their related mechanical and thermal properties. The study of crushing and sintering is presented. For the first time, experimental results are confronted with theoretical models in order to deduce the densification and grain growth mechanisms. By the comprehension of the various physicochemical phenomena occurring during the various stages of the monazite pellets elaboration process (powder synthesis, crushing, sintering...), this work allowed the development of a protocol of elaboration of controlled microstructure monazite TR 3+ PO 4 pellets. The determination of some mechanical and thermal

  18. Relationships among oxidation-reduction and acid-base properties of the actinides in high oxidation states

    International Nuclear Information System (INIS)

    Morss, L.R.

    1992-01-01

    The first chemical identification of plutonium, its subsequent isolation on the macroscopic scale, and more recent chemical separation schemes were achieved by taking advantage of the differences among the oxidation states of uranium, neptunium, and plutonium. Many acid-base properties modify the relative stabilities of oxidation states of the actinides. In the solid state, strongly basic compounds such as Cs 2 O yield complex oxides with oxidation states of Np(VII), Pu(VI), and Am(VI) whereas more acidic compounds such as CsF yield complex fluorides with lower oxidation states. In aqueous solution, high basicity and strongly covalent complexes favor high oxidation states. In nonaqueous solvent systems, high acidity generally favors low oxidation states. This paper elucidates and attempts to interpret the effects of these acid-base properties in a systematic fashion

  19. Spin–orbit coupling in actinide cations

    DEFF Research Database (Denmark)

    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...... 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....

  20. Actinide metals

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Paul L. [Geochem Australia, Kiama, NSW (Australia); Ekberg, Christian [Chalmers Univ. of Technology, Goeteborg (Sweden). Nuclear Chemistry/Industrial Materials Recycling

    2016-07-01

    All isotopes of actinium are radioactive and exist in aqueous solution only in the trivalent state. There have been very few studies on the hydrolytic reactions of actinium(III). The hydrolysis reactions for uranium would only be important in alkaline pH conditions. Thermodynamic parameters for the hydrolysis species of uranium(VI) and its oxide and hydroxide phases can be determined from the stability and solubility constants. The hydrolytic behaviour of neptunium(VI) is quite similar to that of uranium(VI). The solubility constant of NpO{sub 2}OH(am) has been reported a number of times for both zero ionic strength and in fixed ionic strength media. Americium can form four oxidation states in aqueous solution, namely trivalent, tetravalent, pentavalent and hexavalent. Desire, Hussonnois and Guillaumont determined stability constants for the species AmOH{sup 2+} for the actinides, plutonium(III), americium(III), curium(III), berkelium(III) and californium(III) using a solvent extraction technique.

  1. Actinide metals

    International Nuclear Information System (INIS)

    Brown, Paul L.; Ekberg, Christian

    2016-01-01

    All isotopes of actinium are radioactive and exist in aqueous solution only in the trivalent state. There have been very few studies on the hydrolytic reactions of actinium(III). The hydrolysis reactions for uranium would only be important in alkaline pH conditions. Thermodynamic parameters for the hydrolysis species of uranium(VI) and its oxide and hydroxide phases can be determined from the stability and solubility constants. The hydrolytic behaviour of neptunium(VI) is quite similar to that of uranium(VI). The solubility constant of NpO 2 OH(am) has been reported a number of times for both zero ionic strength and in fixed ionic strength media. Americium can form four oxidation states in aqueous solution, namely trivalent, tetravalent, pentavalent and hexavalent. Desire, Hussonnois and Guillaumont determined stability constants for the species AmOH 2+ for the actinides, plutonium(III), americium(III), curium(III), berkelium(III) and californium(III) using a solvent extraction technique.

  2. The reduced transition probabilities for excited states of rare-earths and actinide even-even nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Ghumman, S. S. [Department of Physics, Sant Longowal Institute of Engineering and Technology (Deemed University), Longowal, Sangrur-148106, Punjab, India s-ghumman@yahoo.com (India)

    2015-08-28

    The theoretical B(E2) ratios have been calculated on DF, DR and Krutov models. A simple method based on the work of Arima and Iachello is used to calculate the reduced transition probabilities within SU(3) limit of IBA-I framework. The reduced E2 transition probabilities from second excited states of rare-earths and actinide even–even nuclei calculated from experimental energies and intensities from recent data, have been found to compare better with those calculated on the Krutov model and the SU(3) limit of IBA than the DR and DF models.

  3. Electrochemical and spectroscopic studies of some less stable oxidation states of selected lanthanide and actinide elements

    International Nuclear Information System (INIS)

    Hobart, D.E.

    1981-06-01

    Simultaneous observation of electrochemical and spectroscopic properties (spectroelectrochemistry) at optically transparent electrodes (OTE's) was used to study some less stable oxidation states of selected lanthanide and actinide elements. Cyclic voltammetry at microelectrodes was used in conjunction with spectroelectrochemistry for the study of redox couples. Additional analytical techniques were used. The formal reduction potential (E 0 ') values of the M(III)/M(II) redox couples in 1 M KCl at pH 6 were -0.34 +- 0.01 V for Eu, -1.18 +- 0.01 V for Yb, and -1.50 +- 0.01 V for Sm. Spectropotentiostatic determination of E 0 ' for the Eu(III)/Eu(II) redox couple yielded a value of -0.391 +- 0.005 V. Spectropotentiostatic measurement of the Ce(IV)/Ce(III) redox couple in concentrated carbonate solution gave E 0 ' equal to 0.051 +- 0.005 V, which is about 1.7 V less positive than the E 0 ' value in noncomplexing solution. This same difference in potential was observed for the E 0 ' values of the Pr(IV)/Pr(III) and Tb(IV)/Tb(III) redox couples in carbonate solution, and thus Pr(IV) and Tb(IV) were stabilized in this medium. The U(VI)/U(V)/U(IV) and U(IV)/U(III) redox couples were studied in 1 M KCl at OTE's. Spectropotentiostatic measurement of the Np(VI)/Np(V) redox couple in 1 M HClO 4 gave an E 0 ' value of 1.140 +- 0.005 V. An E 0 ' value of 0.46 +- 0.01 V for the Np(VII)/Np(VI) couple was found by voltammetry. Oxidation of Am(III) was studied in concentrated carbonate solution, and a reversible cyclic voltammogram for the Am(IV)/Am(III) couple yielded E 0 ' = 0.92 +- 0.01 V in this medium; this value was used to estimate the standard reduction potential (E 0 ) of the couple as 2.62 +- 0.01 V. Attempts to oxidize Cm(III) in concentrated carbonate solution were not successful which suggests that the predicted E 0 value for the Cm(IV)/Cm(III) redox couple may be in error

  4. Minor actinides transmutation potential: state of art for GEN IV sodium cooled fast reactors

    International Nuclear Information System (INIS)

    Buiron, Laurent

    2015-01-01

    In the frame of the R and D program relative to the 1991 French act on nuclear waste management, fast neutron systems have shown relevant characteristics that meet both requirements on sustainable resources management and waste minimization. They also offer flexibility by mean of burner or breeder configurations allowing mastering plutonium inventory without significant impact on core safety. From the technological point of view, sodium cooled fast reactor are considered in order to achieve mean term industrial deployment. The present document summaries the main results of R and D program on minor actinides transmutation in sodium fast reactor since 2006 following recommendation of the first part of the 1991 French act. Both homogeneous and heterogeneous management achievable performances are presented for 'evolutionary' SFR V2B core as well as low void worth CFV core for industrial scale configurations (1500 MWe). Minor actinides transmutation could be demonstrated in the ASTRID reactor with the following configurations: - a 2%vol Americium content for the homogeneous mode, - a 10%vol Americium content for the heterogeneous mode, without any substantial modification of the main core safety parameters and only limited impacts on the associated fuel cycle (manufacturing issues are not considered here). In order to achieve such goal, a wide range of experimental irradiations driven by transmutation scenarios have to be performed for both homogeneous and heterogeneous minor actinides management. (author) [fr

  5. Extraction chromatogrpahy of actinides, ch. 7

    International Nuclear Information System (INIS)

    Mueller, W.

    1975-01-01

    This review on extraction chromatography of actinides emphasizes the important usage of neutral (Tributylphosphate), basic (substituted ammonium salts), and acidic (HDEHP) extractants, and their application to separations of actinides in the di-to hexavalent oxidation state. Furthermore, the actinide extraction by ketones, ethers, alcohols and β-diketones is discussed

  6. Extraction chromatography of actinides

    International Nuclear Information System (INIS)

    Muller, W.

    1978-01-01

    Extraction chromatography of actinides in the oxidation state from 2 to 6 is reviewed. Data on using neutral (tbp), basic (substituted ammonium salts) and acidic [di-(2-ethylhexyl)-phosphoric acid (D2EHPA)] extracting agents ketones, esters, alcohols and β-diketones in this method are given. Using the example of actinide separation using D2EHPA, discussed are factors influencing the efficiency of their chromatography separation (nature and particle size of the carrier materials, extracting agents amount on the carrier, temperature and elution rate)

  7. The transuranium elements: Members of the 5f series

    International Nuclear Information System (INIS)

    Gruen, D.M.

    1990-01-01

    The Symposium to commemorate the fiftieth anniversary of the discovery of the transuranium elements is an appropriate occasion on which to review the history of the development of ideas concerning the electronic structure of the new elements which, by determining their chemistry, would fix their position in the Periodic Table. Seaborg's actinide hypothesis was based on the properties of Np and Pu, as well as those of transuranium elements discovered after 1940. The elaboration of this hypothesis, with its profound consequences for our current understanding of the Periodic Table, will be traced from its beginnings to its present status, making use of the wealth of spectroscopic and magnetic data accumulated over the years to draw conclusions about the electronic structure of the actinides. Np and Pu, in particular, offered the first possibility for detailed study of the binding energies of 5f versus 6d electrons. The rich chemistry of these two elements is still providing new insights into the subtleties of electronic structure

  8. Synthesis and crystal chemistry of transuranium element chalcogenides. Contribution to the study of the 5f electron localization

    International Nuclear Information System (INIS)

    Damien, Daniel.

    1976-09-01

    The synthesis and crystal chemistry of Np, Pu, Am and Cm transuranium element chalcogenides are described. From plutonium, transuranium element chalcogenides exhibit the same crystal structure as their rare-earth homologues. The variations of the lattice constants of these compounds in terms of the atomic number are characterized by the lack of the 5f contraction and are interpreted by a localization of the 5f electrons depending upon the considered transuranium element, the nature of the ligand and the crystal structure. To compare the degree of magnitude of the 5f electron delocalization in various compounds, a delocalization scale is proposed based on a comparison between the molar volumes of actinide and isostructural lanthanide compounds. This scale provides a delocalization coefficient for each compound under study. Examination of these coefficients shows that the 5f electrons, in series of actinide compounds, become localized when going from neptunium to curium and that the delocalization process does not only depend upon overlaps between 5f-6d orbitals of neighbouring actinide atoms; the delocalization coefficients show the existence of a secondary delocalization effect due to overlaps between the p anion and f actinide orbitals which are more important for the Vb anion group (N, P, As, Sb) than for the Vib one (S,Se,Te) [fr

  9. 3 and 4 oxidation state element solubilities in borosilicate glasses. Implement to actinides in nuclear glasses; Solubilite des elements aux degres d'oxydation (3) et (4) dans les verres de borosilicate. Application aux actinides dans les verres nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Cachia, J.N

    2005-12-15

    In order to ensure optimal radionuclides containment, the knowledge of the actinide loading limits in nuclear waste glasses and also the comprehension of the solubilization mechanisms of these elements are essential. A first part of this manuscript deals with the study of the differences in solubility of the tri and tetravalent elements (actinides and surrogates) particularly in function of the melting temperature. The results obtained indicate that trivalent elements (La, Gd, Nd, Am, Cm) exhibit a higher solubility than tetravalent elements (Hf, Th, Pu). Consequently, it was planned to reduce plutonium at the oxidation state (III), the later being essentially tetravalent in borosilicate glasses. An innovating reduction process of multi-valent elements (cerium, plutonium) using silicon nitride has been developed in a second part of this work. Reduced plutonium-bearing glasses synthesized by Si{sub 3}N{sub 4} addition made it possible to double the plutonium solubility from 2 to 4 wt% at 1200 deg C. A structural approach to investigate the differences between tri and tetravalent elements was finally undertaken. These investigations were carried out by X-rays Absorption Spectroscopy (EXAFS) and NMR. Trivalent rare earth and actinide elements seem to behave as network modifiers while tetravalent elements rather present true intermediaries' behaviour. (author)

  10. The cosmic ray actinide charge spectrum derived from a 10 m2 array of solid state nuclear track detectors in Earth orbit

    International Nuclear Information System (INIS)

    Donnelly, J.; Thompson, A.; O'Sullivan, D.; Drury, L.O'C.; Wenzel, K.-P.

    2001-01-01

    The DIAS-ESTEC Ultra Heavy Cosmic Ray Experiment (UHCRE) on the Long Duration Exposure Facility, collected approximately 3000 cosmic ray nuclei with Z>65 in the energy region E>1.5 GeV nucleon -1 during a six year exposure in Earth orbit. The entire accessible collecting area of the solid state nuclear track detector (SSNTD) array has been scanned for actinides, yielding a sample of 30 from an exposure of ∼150 m 2 sr yr. The UHCRE experimental setup is described and the observed charge spectrum presented. The current best value for the cosmic ray actinide relative abundance, (Z>88)/(74≤Z≤87), is reported

  11. Molecular and electronic structure of actinide hexa-cyanoferrates; Structure moleculaire et electronique des hexacyanoferrates d'actinides

    Energy Technology Data Exchange (ETDEWEB)

    Bonhoure, I

    2001-07-01

    The goal of this work is to improve our knowledge on the actinide-ligand bond properties. To this end, the hexacyanoferrate entities have been used as pre-organized ligand. We have synthesized, using mild chemistry, the following series of complexes: An{sup IV}[Fe{sup II}(CN){sub 6}].xH{sub 2}O (An = Th, U, Np, Pu); Am{sup III}[Fe{sup III}(CN){sub 6}].xH{sub 2}O; Pu {sup III}[Co{sup III}(CN){sub 6}].xH{sub 2}O and K(H?)An{sup III}[Fe{sup II}(CN){sub 6}].xH{sub 2}O (An = Pu, Am). The metal oxidation states have been obtained thanks to the {nu}{sub CN}, stretching vibration and to the actinide L{sub III} absorption edge studies. As Prussian Blue, the An{sup IV}[Fe{sup II}(CN){sub 6}].xH{sub 2}O (An = Np, Pu) are class II of Robin and Day compounds. X-ray Diffraction has shown besides that these complexes crystallize in the P6{sub 3}/m space group, as the isomorphic LaKFe(CN){sub 6}.4H{sub 2}O complex used as structural model. The EXAFS oscillations at the iron K edge and at the An L{sub III} edge allowed to determine the An-N, An-O, Fe-C and Fe-N distances. The display of the multiple scattering paths for both edges explains the actinide contribution absence at the iron edge, whereas the iron signature is present at the actinide edge. We have shown that the actinide coordination sphere in actinides hexa-cyanoferrates is comparable to the one of lanthanides. However, the actinides typical behavior towards the lanthanides is brought to the fore by the An{sup IV} versus Ln{sup III} ions presence in this family of complexes. Contrarily to the 4f electrons, the 5f electrons influence the electronic properties of the compounds of this family. However, the gap between the An-N and Ln-N distances towards the corresponding metals ionic radii do not show any covalence bond evolution between the actinide and lanthanide series. (author)

  12. Actinide recycle

    Energy Technology Data Exchange (ETDEWEB)

    Till, C; Chang, Y [Argonne National Laboratory, Argonne, IL (United States)

    1990-07-01

    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.

  13. Actinide recycle

    International Nuclear Information System (INIS)

    Till, C.; Chang, Y.

    1990-01-01

    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

  14. Systematic thermodynamic properties of actinide metal-oxygen systems at high temperatures: Emphasis on lower valence states

    International Nuclear Information System (INIS)

    Ackermann, R.J.; Chandrasekharaiah, M.S.

    1975-01-01

    The thermodynamic data for the actinide metals and oxides (thorium to curium ) have been assessed, examined for consistency, and compared with the lanthanides. Correlations relating the enthalpies of formation of the solid oxides with the corresponding aquo ions make possible the estimation of the thermodynamic properties of AmO 2 (s) and Am 2 O 3 (s) which are in accordance with vaporization data. The known thermodynamic properties of the substoichiometric dioxides MOsub(2-x)(s) at high temperatures demonstrate the relative stabilities of valence states less than 4+ and lead to the examination of stability requirements for the sesquioxides M 2 O 3 (s) and the monoxides MO(s). Sequential trends in the gaseous metals, monoxides and dioxides are examined, compared, and contrasted with the lanthanides. (author)

  15. Process of converting actinide ions present in the solid residues of a sulphating process for radioactive solid waste containing actinides into a useful state

    International Nuclear Information System (INIS)

    Wieczorek, H.; Oser, B.

    1985-01-01

    Stages of the process: a) The residue is dissolved in water or 1 to 2 mole nitric acid, where the greater part is dissolved. b) The solution formed is separated from the insoluble part of the residue and is heated to a temperature below its boiling point. c) The hot solution has an aquaeous barium nitrate solution added to it with a quantity which slightly exceeds that required for the stochiometric complete precipitation of the sulphate ions. The solution is kept at the selected temperature for a period of 0.5 to 2 hours. d) After subsequent cooling to room temperature, the precipitated barium sulphate is separated and e) the actinide-nitrate solution is fed into an extractive reprocessing process. (orig./PW) [de

  16. Fermi energy 5f spectral weight variation in uranium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Denlinger, J.D.; Clack, J.; Allen, J.W. [Univ. of Michigan, Ann Arbor, MI (United States)] [and others

    1997-04-01

    Uranium materials display a wide range of thermal, electrical and magnetic properties, often exotic. For more than a decade there have been efforts to use photoemission spectroscopy to develop a systematic and unified understanding of the 5f electron states giving rise to this behavior. These efforts have been hampered by a paucity of systems where changes in transport properties are accompanied by substantial spectral changes, so as to allow an attempt to correlate the two kinds of properties within some model. The authors have made resonant photoemission measurements to extract the 5f spectral weight in three systems which show varying degrees of promise of permitting such an attempt, Y{sub 1{minus}x}U{sub x}Pd{sub 3}, U(Pd{sub x}Pt{sub 1{minus}x}){sub 3} and U(Pd{sub x}Cu{sub 1{minus}x}){sub 5}. They have also measured U 4f core level spectra. The 4f spectra can be modeled with some success by the impurity Anderson model (IAM), and the 5f spectra are currently being analyzed in that framework. The IAM characterizes the 5f-electrons of a single site by an f binding energy {epsilon}{sub f}, an f Coulomb interaction and a hybridization V to conduction electrons. Latent in the model are the phenomena of 5f mixed valence and the Kondo effect.

  17. Magnetic and electronic properties of some actinide intermetallic compounds

    International Nuclear Information System (INIS)

    Yaar, Ilan

    1992-06-01

    The electronic structure and magnetic properties of the light actinide intermetallic compounds are often related to interplay between localized and itinerant (band like) behavior of the 5f- electrons. In the present work, the properties of some actinide, mainly Np, intermetallic compounds were studied by Mossbauer effect, ac and dc susceptibility, X-ray and Neutron diffraction techniques. 1. NpX 2 (X=Ga,Si) - Both compounds order ferromagnetically at TC=55(2) and 48(2) K respectively. A comparison of our data with the results for other NpX 2 (X=Al,As,Sb,Tl) compounds indicates that NpGa 2 is a highly localized 5f electron system, whereas in NpSi 2 the 5f electrons are partially delocalized. The magnetic properties of NpX 2 compounds can neither be consistently explained within the conventional crystal electric field picture (CEF) nor by takink into account hybridization dressing of local spin density models. 2. NpX 3 (X=Ga,Si,In,Al) in the cubic AuCu 3 (Pm3m) crystallographic structure - From the Mossbauer isomer shift (IS) data we argue that the Np ion in the NpX 3 family is close to the formal 3+ (5I 4 ) charge state. The magnetic moment of the Np in NpSi 3 is totally suppressed whereas in NpGa 3 and NpAl 3 a localized (narrow band) moment is established. However, in NpIn 3 at 4.2 K, a modulated magnetic moment (0-1.5μB) is observed. Comparing the magnetic behavior of the NpX 3 family (X=Si,Ge,Ga, Al,In and Sn), we find an impressive variation of the magnetic properties, from temperature independent paramagnetism (TIP), localized and modulated ordered moments, to the formation of a concentrated Kondo lattice. Hybridization of 5f electrons with ligand electrons appears to play a crucial role in establishing these magnetic properties. However, at present a consistent theoretical picture can not be drawn. 3. XFe 4 Al 8 (X=Ho,Np,U) spin galss (SG) systems in the ThMn 12 (I 4 /mmm) crystallographic structure - Localized and itinerant behaviour of the f electrons

  18. Recent development in computational actinide chemistry

    International Nuclear Information System (INIS)

    Li Jun

    2008-01-01

    Ever since the Manhattan project in World War II, actinide chemistry has been essential for nuclear science and technology. Yet scientists still seek the ability to interpret and predict chemical and physical properties of actinide compounds and materials using first-principle theory and computational modeling. Actinide compounds are challenging to computational chemistry because of their complicated electron correlation effects and relativistic effects, including spin-orbit coupling effects. There have been significant developments in theoretical studies on actinide compounds in the past several years. The theoretical capabilities coupled with new experimental characterization techniques now offer a powerful combination for unraveling the complexities of actinide chemistry. In this talk, we will provide an overview of our own research in this field, with particular emphasis on applications of relativistic density functional and ab initio quantum chemical methods to the geometries, electronic structures, spectroscopy and excited-state properties of small actinide molecules such as CUO and UO 2 and some large actinide compounds relevant to separation and environment science. The performance of various density functional approaches and wavefunction theory-based electron correlation methods will be compared. The results of computational modeling on the vibrational, electronic, and NMR spectra of actinide compounds will be briefly discussed as well [1-4]. We will show that progress in relativistic quantum chemistry, computer hardware and computational chemistry software has enabled computational actinide chemistry to emerge as a powerful and predictive tool for research in actinide chemistry. (authors)

  19. Nonaqueous method for dissolving lanthanide and actinide metals

    International Nuclear Information System (INIS)

    Crisler, L.R.

    1975-01-01

    Lanthanide and actinide beta-diketonate complex molecular compounds are produced by reacting a beta-diketone compound with a lanthanide or actinide element in the elemental metallic state in a mixture of carbon tetrachloride and methanol

  20. Actinide separation by electrorefining

    International Nuclear Information System (INIS)

    Fusselman, S.P.; Gay, R.L.; Grantham, L.F.; Grimmett, D.L.; Roy, J.J.; Inoue, T.; Hijikata, T.; Krueger, C.L.; Storvick, T.S.; Takahashi, N.

    1995-01-01

    TRUMP-S is a pyrochemical process being developed for the recovery of actinides from PUREX wastes. This paper describes development of the electrochemical partitioning step for recovery of actinides in the TRUMP-S process. The objectives are to remove 99 % of each actinide from PUREX wastes, with a product that is > 90 % actinides. Laboratory tests indicate that > 99 % of actinides can be removed in the electrochemical partitioning step. A dynamic (not equilibrium) process model predicts that 90 wt % product actinide content can be achieved through 99 % actinide removal. Accuracy of model simulation results were confirmed in tests with rare earths. (authors)

  1. 1981 Annual Status Report. Plutonium fuels and actinide programme

    International Nuclear Information System (INIS)

    1981-01-01

    In this 1981 report the work carried out by the European Institute for Transuranium elements is reviewed. Main topics are: operation limits of plutonium fuels: swelling of advanced fuels, oxide fuel transients, equation of state of nuclear materials; actinide cycle safety: formation of actinides (FACT), safe handling of plutonium fuel (SHAPE), aspects of the head-end processing of carbide fuel (RECARB); actinide research: crystal chemistry, solid state studies, applied actinide research

  2. Electronic structure of the light actinides

    International Nuclear Information System (INIS)

    Dunlap, B.D.

    1976-01-01

    In the last few years, considerable advances have been made in our understanding of the properties of the light actinides. Although these are 5f transition elements formally equivalent to the lanthanide (4f) elements, these materials show a much more varied behavior due to the larger spatial extent and ionizability of the 5f electrons. A review is given of some areas of current interest, especially where hyperfine measurements have played an active role. These include studies of a variety of magnetic phenomena, systematics of isomer shift measurements, and studies of paramagnetic relaxation

  3. Calculated Bulk Properties of the Actinide Metals

    DEFF Research Database (Denmark)

    Skriver, Hans Lomholt; Andersen, O. K.; Johansson, B.

    1978-01-01

    Self-consistent relativistic calculations of the electronic properties for seven actinides (Ac-Am) have been performed using the linear muffin-tin orbitals method within the atomic-sphere approximation. Exchange and correlation were included in the local spin-density scheme. The theory explains...... the variation of the atomic volume and the bulk modulus through the 5f series in terms of an increasing 5f binding up to plutonium followed by a sudden localisation (through complete spin polarisation) in americium...

  4. Actinide science with soft x-ray synchrotron radiation

    International Nuclear Information System (INIS)

    Shuh, D.

    2002-01-01

    Several workshops, some dating back more than fifteen years, recognised both the potential scientific impact and opportunities that would be made available by the capability to investigate actinide materials in the vacuum ultraviolet (VUV)/soft X-ray region of the synchrotron radiation (SR) spectrum. This spectral region revolutionized the approach to surface materials chemistry and physics nearly two decades ego. The actinide science community was unable to capitalize on these SR methodologies for the study of actinide materials until recently because of radiological safety concerns. ,The Advanced Light Source (ALS) at LBNL is a third-generation light source providing state-of-the-art performance in the VUV/soft X-ray region. Along with corresponding improvements in detector and vacuum technology, the ALS has rendered experiments with small amounts of actinide materials possible. In particular, it has been the emergence and development of micro-spectroscopic techniques that have enabled investigations of actinide materials at the ALS. The primary methods for the experimental investigation of actinide materials in the VUV/soft X-ray region are the complementary photoelectron spectroscopies, near-edge X-ray absorption fine structure (NEXAFS) and X-ray emission spectroscopy (XES) techniques. Resonant photo-emission is capable of resolving the 5f electron contributions to actinide bonding and can be used to characterise the electronic structure of actinide materials. This technique is clearly a most important methodology afforded by the tunable SR source. Core level and valence band photoelectron spectroscopies are valuable for the characterisation of the electronic properties of actinide materials, as well as for general analytical purposes. High-resolution core-level photo-emission and resonant photo-emission measurements from the a (monoclinic) and δ (FCC) allotropic phases of plutonium metal have been collected on beam line 7.0 at the ALS and the spectra show

  5. The cosmic ray actinide charge spectrum derived from a 10 m{sup 2} array of solid state nuclear track detectors in Earth orbit

    Energy Technology Data Exchange (ETDEWEB)

    Donnelly, J. E-mail: jd@cp.dias.ie; Thompson, A.; O' Sullivan, D.; Drury, L.O' C.; Wenzel, K.-P

    2001-06-01

    The DIAS-ESTEC Ultra Heavy Cosmic Ray Experiment (UHCRE) on the Long Duration Exposure Facility, collected approximately 3000 cosmic ray nuclei with Z>65 in the energy region E>1.5 GeV nucleon{sup -1} during a six year exposure in Earth orbit. The entire accessible collecting area of the solid state nuclear track detector (SSNTD) array has been scanned for actinides, yielding a sample of 30 from an exposure of {approx}150 m{sup 2} sr yr. The UHCRE experimental setup is described and the observed charge spectrum presented. The current best value for the cosmic ray actinide relative abundance, (Z>88)/(74{<=}Z{<=}87), is reported.

  6. Actinide speciation in the environment

    International Nuclear Information System (INIS)

    Choppin, G.R.

    2007-01-01

    Nuclear test explosions and nuclear reactor wastes and accidents have released large amounts of radioactivity into the environment. Actinide ions in waters often are not in a state of thermodynamic equilibrium and their solubility and migration behavior is related to the form in which the nuclides are introduced into the aquatic system. Chemical speciation, oxidation state, redox reactions, and sorption characteristics are necessary in predicting solubility of the different actinides, their migration behaviors and their potential effects on marine biota. The most significant of these variables is the oxidation state of the metal ion as the simultaneous presence of more than one oxidation state for some actinides in a solution complicates actinide environmental behavior. Both Np(V)O 2 + and Pu(V)O 2 + , the most significant soluble states in natural oxic waters, are relatively noncomplexing and resistant to hydrolysis and subsequent precipitation. The solubility of NpO 2 + can be as high as 10 -4 M while that of PuO 2 + is much more limited by reduction to the insoluble tetravalent species, Pu(OH) 4 , (pK sp ≥56) but which can be present in the pentavalent form in aqautic phases as colloidal material. The solubility of hexavalent UO 2 2+ in sea water is relatively high due to formation of carbonate complexes. The insoluble trivalent americium hydroxocarbonate, Am(OH)(CO 3 ) is the limiting species for the solubility of Am(III) in sea water. Thorium(IV) is present as Th(OH) 4 , in colloidal form. The chemistry of actinide ions in the environment is reviewed to show the spectrum of reactions that can occur in natural waters which must be considered in assessing the environmental behavior of actinides. Much is understood about sorption of actinides on surfaces, the mode of migration of actinides in such waters and the potential effects of these radioactive species on marine biota, but much more understanding of the behavior of the actinides in the environment is

  7. Neutron scattering studies of the actinides

    International Nuclear Information System (INIS)

    Lander, G.H.

    1979-01-01

    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 UO 2 , 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. 4f and 5f trivalent ions complexation by diamides and uses in solvent extraction

    International Nuclear Information System (INIS)

    Huber, H.

    1984-06-01

    Extractive properties of N,N'-tetraalkylmalonamides were investigated in view to separate the actinides contained in highly radioactive wastes. N,N'-dimethyldioctylmalonamide (DMDOMA) was selected. It extracts trivalent actinide and lanthanide from concentrated nitric acid. Mineral acids extraction was studied, especially HNO 3 extraction. The distribution of HNO 3 can be interpreted by assuming that in the organic phase three main species are present: HNO 3 (DMDOMA) 2 , HNO 3 DMDOMA, (HNO 3 ) 2 DMDOMA. 5f and 4f trivalent ions are extracted according to the mechanism: M 3+ + 3NO 3 - + 4DMDOMA in equilibrium with [M(DMDOMA) 2 (NO 3 ) 3 ].(DMDOMA) 2 . The extraction of important ions like U(VI), Np(V), Pu(IV), Pu(VI), Zr(IV) and Fe(III) was investigated. The results showed that DMDOMA behave line the carbamoylmethylenephosphonates and could be an interesting alternative to these organophosphorus extractants [fr

  9. Actinide metal processing

    International Nuclear Information System (INIS)

    Sauer, N.N.; Watkin, J.G.

    1992-01-01

    A process for converting an actinide metal such as thorium, uranium, or plutonium to an actinide oxide material by admixing the actinide metal in an aqueous medium with a hypochlorite as an oxidizing agent for sufficient time to form the actinide oxide material and recovering the actinide oxide material is described together with a low temperature process for preparing an actinide oxide nitrate such as uranyl nitrate. Additionally, a composition of matter comprising the reaction product of uranium metal and sodium hypochlorite is provided, the reaction product being an essentially insoluble uranium oxide material suitable for disposal or long term storage

  10. 33rd Actinide Separations Conference

    Energy Technology Data Exchange (ETDEWEB)

    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.

  11. 33rd Actinide Separations Conference

    International Nuclear Information System (INIS)

    McDonald, L.M.; Wilk, P.A.

    2009-01-01

    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.

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

    International Nuclear Information System (INIS)

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

    1999-01-01

    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)

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

    International Nuclear Information System (INIS)

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

    1999-01-01

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  15. Magnetic susceptibility measurements of σ plutonium alloys. Contribution to the study of the 5f electrons localization in the plutonium

    International Nuclear Information System (INIS)

    Meot-Reymond, S.

    1996-01-01

    Physical properties of actinide metals are essentially ruled by the 5f electrons localization. From a theoretically point of view, this localization is more important in the δ-phase than in the α-one. To compare their magnetic behaviour, low temperature magnetic susceptibility measurements have been performed and previous-resistivity data have been analysed. Experimental results and theoretical data can be conciliate by the existence of a Kondo effect in the δ-Pu phase. (author)

  16. The nature of chemical bonding in actinide and lanthanide ferrocyanides determined by X-ray absorption spectroscopy and density functional theory.

    Science.gov (United States)

    Dumas, Thomas; Guillaumont, Dominique; Fillaux, Clara; Scheinost, Andreas; Moisy, Philippe; Petit, Sébastien; Shuh, David K; Tyliszczak, Tolek; Den Auwer, Christophe

    2016-01-28

    The electronic properties of actinide cations are of fundamental interest to describe intramolecular interactions and chemical bonding in the context of nuclear waste reprocessing or direct storage. The 5f and 6d orbitals are the first partially or totally vacant states in these elements, and the nature of the actinide ligand bonds is related to their ability to overlap with ligand orbitals. Because of its chemical and orbital selectivities, X-ray absorption spectroscopy (XAS) is an effective probe of actinide species frontier orbitals and for understanding actinide cation reactivity toward chelating ligands. The soft X-ray probes of the light elements provide better resolution than actinide L3-edges to obtain electronic information from the ligand. Thus coupling simulations to experimental soft X-ray spectral measurements and complementary quantum chemical calculations yields quantitative information on chemical bonding. In this study, soft X-ray XAS at the K-edges of C and N, and the L2,3-edges of Fe was used to investigate the electronic structures of the well-known ferrocyanide complexes K4Fe(II)(CN)6, thorium hexacyanoferrate Th(IV)Fe(II)(CN)6, and neodymium hexacyanoferrate KNd(III)Fe(II)(CN)6. The soft X-ray spectra were simulated based on quantum chemical calculations. Our results highlight the orbital overlapping effects and atomic effective charges in the Fe(II)(CN)6 building block. In addition to providing a detailed description of the electronic structure of the ferrocyanide complex (K4Fe(II)(CN)6), the results strongly contribute to confirming the actinide 5f and 6d orbital oddity in comparison to lanthanide 4f and 5d.

  17. Review of actinide decorporation with chelating agents

    Energy Technology Data Exchange (ETDEWEB)

    Ansoborlo, E. [CEA Valrho, Dir. de l' Energie Nucleaire (DEN/DRCP/CETAMA), 30 - Marcoule (France); Amekraz, B.; Moulin, Ch. [CEA Saclay, Dept. de Physico-Chimie (DEN/DPC/SECR), 91 - Gif sur Yvette (France); Moulin, V. [CEA Saclay, Dir. du Developpement et de l' Innovation Nucleares (DEN/DDIN/MR), 91 - Gif Sur Yvette (France); Taran, F. [CEA Saclay (DSV/DBJC/SMMCB), 91 - Gif-sur-Yvette (France); Bailly, Th.; Burgada, R. [Centre National de la Recherche Scientifique (CNRS/LCSB/UMR 7033), 93 - Bobigny (France); Henge-Napoli, M.H. [CEA Valrho, Site de Marcoule (INSTN), 30 (France); Jeanson, A.; Den Auwer, Ch.; Bonin, L.; Moisy, Ph. [CEA Valrho, Dir. de l' Energie Nucleaire (DEN/DRCP/SCPS), 30 - Marcoule (France)

    2007-10-15

    In case of accidental release of radionuclides in a nuclear facility or in the environment, internal contamination (inhalation, ingestion or wound) with actinides represents a severe health risk to human beings. It is therefore important to provide effective chelation therapy or decorporation to reduce acute radiation damage, chemical toxicity, and late radiation effects. Speciation governs bioavailability and toxicity of elements and it is a prerequisite tool for the design and success of new ligands or chelating agents. The purpose of this review is to present the state-of-the-art of actinide decorporation within biological media, to recall briefly actinide metabolism, to list the basic constraints of actinide-ligand for development, to describe main tools developed and used for decorporation studies, to review mainly the chelating agents tested for actinides, and finally to conclude on the future trends in this field. (authors)

  18. Actinide cation-cation complexes

    International Nuclear Information System (INIS)

    Stoyer, N.J.; Seaborg, G.T.

    1994-12-01

    The +5 oxidation state of U, Np, Pu, and Am is a linear dioxo cation (AnO 2 + ) 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 AnO 2 + ; therefore, cation-cation complexes indicate something unique about AnO 2 + cations compared to actinide cations in general. The first cation-cation complex, NpO 2 + ·UO 2 2+ , was reported by Sullivan, Hindman, and Zielen in 1961. Of the four actinides that form AnO 2 + species, the cation-cation complexes of NpO 2 + have been studied most extensively while the other actinides have not. The only PuO 2 + cation-cation complexes that have been studied are with Fe 3+ and Cr 3+ 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 NpO 2 + ·UO 2 2+ , NpO 2 + ·Th 4+ , PuO 2 + ·UO 2 2+ , and PuO 2 + ·Th 4+ 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

  19. Strong coupling between localized 5f moments and itinerant quasiparticles in the ferromagnetic superconductor UGe2

    Science.gov (United States)

    Zhang, Wen; Liu, Yi; Wang, Xiaoying; Zhang, Yun; Xie, Donghua

    2018-03-01

    The heavy fermion physics arises from the complex interplay of nearly localized 4f/5f electrons and itinerant band-like ones, yielding heavy quasiparticles with an effective mass about 100 times (or more) of the bare electrons. Recently, experimental and theoretical investigations point out a localized and delocalized dual nature in actinide compounds, where itinerant quasiparticles account for the unconventional superconductivity in the vicinity of a magnetic instability. Here we report the strong coupling between localized 5f moments and itinerant quasiparticles in the ferromagnetic superconductor UGe2. The coupling is nearly antiferromagnetic. As embedded in the ferromagnetic matrix of localized 5f moments below {T}{{C}}≈ 52 {{K}}, this coupling leads to short-range dynamic correlations of heavy quasiparticles, characterized by fluctuations of magnetic clusters. Those cluster-like spins of itinerant quasiparticles show a broad hump of magnetization at {T}X≈ 28 {{K}}, which is typical for the spin-glass freezing. Thus, our results present the direct observation of itinerant quasiparticles coexisting with localized 5f moments by conventional magnetic measurements, providing a new route into the coexistence between ferromagnetism and superconductivity in heavy fermion systems. Project supported by the National Natural Science Foundation of China (Grant No. 11404297), the Science Challenge Project (Grant No. TZ2016004), and the Science and Technology Foundation of China Academy of Engineering Physics (Grant Nos. 2013B0301050 and 2014A0301013).

  20. Three fatalities associated with the synthetic cannabinoids 5F-ADB, 5F-PB-22, and AB-CHMINACA.

    Science.gov (United States)

    Angerer, V; Jacobi, S; Franz, F; Auwärter, V; Pietsch, J

    2017-12-01

    The use of synthetic cannabinoids (SC) has been widespread in certain groups of drug users for many years. In the scientific literature many intoxication cases and a number of fatalities after the use of synthetic cannabinoids were reported. In this paper three death cases are described with involvement of the synthetic cannabinoids 5F-PB-22, AB-CHMINACA, and 5F-ADB. The three cases occurred in the eastern region of Germany, which is known as a region of high methamphetamine abuse. All decedents were male, between 25 and 41 years old, and had a known history of drug use. Femoral blood concentrations of the synthetic cannabinoids were measured using a validated LC-MS/MS method. The concentration of 5F-PB-22 in the first case was 0.37ng/mL, the concentration of AB-CHMINACA in the second case was approximately 4.1ng/mL (extrapolated) and the 5F-ADB concentration in the third case was 0.38ng/mL. Compared to other published cases the concentrations in the here presented cases seem to be in the lower range. However, taking into account the scene of death, the results of the forensic autopsy and the full toxicological analysis, the deaths can be explained as a direct consequence of consumption of synthetic cannabinoids, although in case one and two relevant amounts of ethanol were found, and in case three trimipramine and olanzapine were present in non-toxic concentrations. It has to be noted that concentrations of synthetic cannabinoids in femoral blood cannot directly be judged as toxic or lethal due to the possibility of postmortem redistribution and the development of tolerance after frequent use. Therefore, all available information has to be considered carefully before stating SC use as the cause of death. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Nuclear magnetic resonance and the question of 5F electron localization in the actinides

    International Nuclear Information System (INIS)

    Fradin, F.Y.

    1976-01-01

    Nuclear magnetic resonance results are presented for a number of NaCl-type compounds and cubic Laves-phase type compounds of uranium, neptunium, and plutonium. Special emphasis is placed on the Knight shift and spin-lattice relaxation time measurements and their interpretation in terms of localized or itinerant pictures of the 5Line integral electrons

  2. Recovery actinide values

    International Nuclear Information System (INIS)

    Horwitz, E.P.; Delphin, W.H.; Mason, G.W.

    1979-01-01

    A process is described for partitioning and recovering actinide values from acidic waste solutions resulting from reprocessing of irradiated nuclear fuels by adding hydroxylammonium nitrate and hydrazine to the waste solution to adjust the valence of the neptunium and plutonium values in the solution to the +4 oxidation state, thus forming a feed solution and contacting the feed solution with an extractant of di-hexoxyethyl phosphoric acid in an organic diluent whereby the actinide values, most of the rare earth values and some fission product values are taken up by the extractant. Separation is achieved by contacting the loaded extractant with two aqueous strip solutions, a nitric acid solution to selectively strip the americium, curium and rare earth values and an oxalate solution of tetramethylammonium hydrogen oxalate and oxalic acid or trimethylammonium hydrogen oxalate to selectively strip the neptunium, plutonium and fission product values. Uranium values remain in the extractant and may be recovered with a phosphoric acid strip. The neptunium and plutonium values are recovered from the oxalate by adding sufficient nitric acid to destroy the complexing ability of the oxalate, forming a second feed, and contacting the second feed with a second extractant of tricaprylmethylammonium nitrate in an inert diluent whereby the neptunium and plutonium values are selectively extracted. The values are recovered from the extractant with formic acid. (author)

  3. Synthesis of tetravalent actinide chlorides. Versatile compounds for actinide chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Maerz, Juliane [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Div. Chemistry of the F-Elements

    2016-07-01

    Anhydrous actinide tetrachlorides (AnCl{sub 4}) were synthesized under mild conditions to provide versatile compounds for actinide chemistry. They enable a direct access to actinide complexes with organic and inorganic ligands.

  4. Comparative Study of f-Element Electronic Structure across a Series of Multimetallic Actinide, Lanthanide-Actinide and Lanthanum-Actinide Complexes Possessing Redox-Active Bridging Ligands

    Energy Technology Data Exchange (ETDEWEB)

    Schelter, Eric J.; Wu, Ruilian; Veauthier, Jacqueline M.; Bauer, Eric D.; Booth, Corwin H.; Thomson, Robert K.; Graves, Christopher R.; John, Kevin D.; Scott, Brian L.; Thompson, Joe D.; Morris, David E.; Kiplinger, Jaqueline L.

    2010-02-24

    A comparative examination of the electronic interactions across a series of trimetallic actinide and mixed lanthanide-actinide and lanthanum-actinide complexes is presented. Using reduced, radical terpyridyl ligands as conduits in a bridging framework to promote intramolecular metal-metal communication, studies containing structural, electrochemical, and X-ray absorption spectroscopy are presented for (C{sub 5}Me{sub 5}){sub 2}An[-N=C(Bn)(tpy-M{l_brace}C{sub 5}Me4R{r_brace}{sub 2})]{sub 2} (where An = Th{sup IV}, U{sup IV}; Bn = CH{sub 2}C{sub 6}H{sub 5}; M = La{sup III}, Sm{sup III}, Yb{sup III}, U{sup III}; R = H, Me, Et) to reveal effects dependent on the identities of the metal ions and R-groups. The electrochemical results show differences in redox energetics at the peripheral 'M' site between complexes and significant wave splitting of the metal- and ligand-based processes indicating substantial electronic interactions between multiple redox sites across the actinide-containing bridge. Most striking is the appearance of strong electronic coupling for the trimetallic Yb{sup III}-U{sup IV}-Yb{sup III}, Sm{sup III}-U{sup IV}-Sm{sup III}, and La{sup III}-U{sup IV}-La{sup III} complexes, [8]{sup -}, [9b]{sup -} and [10b]{sup -}, respectively, whose calculated comproportionation constant K{sub c} is slightly larger than that reported for the benchmark Creutz-Taube ion. X-ray absorption studies for monometallic metallocene complexes of U{sup III}, U{sup IV}, and U{sup V} reveal small but detectable energy differences in the 'white-line' feature of the uranium L{sub III}-edges consistent with these variations in nominal oxidation state. The sum of this data provides evidence of 5f/6d-orbital participation in bonding and electronic delocalization in these multimetallic f-element complexes. An improved, high-yielding synthesis of 4{prime}-cyano-2,2{prime}:6{prime},2{double_prime}-terpyridine is also reported.

  5. Strongly Enhanced Low Energy Alpha-Particle Decay in Heavy Actinide Nuclei and Long-Lived Superdeformed and Hyperdeformed Isomeric States

    CERN Document Server

    Marinov, Amnon; Kolb, D.; Weil, J.L.

    2001-01-01

    Relatively low energy and very enhanced alpha-particle groups have been observed in various actinide fractions produced via secondary reactions in a CERN W target which had been irradiated with 24-GeV protons. In particular, 5.14, 5.27 and 5.53 MeV alpha-particle groups with corresponding half-lives of 3.8(+ -)1.0 y, 625(+ -)84 d and 26(+ -)7 d, have been seen in Bk, Es and Lr-No sources, respectively. The measured energies are a few MeV lower than the known g.s. to g.s. alpha-decays in the corresponding neutron-deficient actinide nuclei. The half-lives are 4 to 7 orders of magnitude shorter than expected from the systematics of alpha-particle decay in this region of nuclei. The deduced evaporation residue cross sections are in the mb region, about 4 orders of magnitude higher than expected. A consistent interpretation of the data is given in terms of production of long-lived isomeric states in the second and third wells of the potential-energy surfaces of the parent nuclei, which decay to the corresponding w...

  6. On the suitability of lanthanides as actinide analogs

    International Nuclear Information System (INIS)

    Raymond, Kenneth; Szigethy, Geza

    2008-01-01

    With the current level of actinide materials used in civilian power generation and the need for safe and efficient methods for the chemical separation of these species from their daughter products and for long-term storage requirements, a detailed understanding of actinide chemistry is of great importance. Due to the unique bonding properties of the f-elements, the lanthanides are commonly used as structural and chemical models for the actinides, but differences in the bonding between these 4f and 5f elements has become a question of immediate applicability to separations technology. This brief overview of actinide coordination chemistry in the Raymond group at UC Berkeley/LBNL examines the validity of using lanthanide analogs as structural models for the actinides, with particular attention paid to single crystal X-ray diffraction structures. Although lanthanides are commonly accepted as reasonable analogs for the actinides, these comparisons suggest the careful study of actinide materials independent of their lanthanide analogs to be of utmost importance to present and future efforts in nuclear industries. (authors)

  7. Successive change regularity of actinide properties with atomic number

    International Nuclear Information System (INIS)

    Yang Xuexian

    1990-08-01

    The development and achievements on chemistry of actinide elements are summarised. The relations of properties of actinides to their electronic configurations of valence electronic shells are discussed. Some anomalies of solid properties, the radius contraction, the stable state effect of f 7n -orbits (n = 0, 1, 2) and the tetrad effect of oxidation states, etc., with atomic number (Z) are described. 31 figures appended show directly the successive change regularity of actinide properties with Z

  8. Actinides: from heavy fermions to plutonium metallurgy

    International Nuclear Information System (INIS)

    Smith, J.L.; Fisk, Z.; Hecker, S.S.

    1984-01-01

    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 UBe 13 and UPt 3 . 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

  9. Advanced Aqueous Separation Systems for Actinide Partitioning

    Energy Technology Data Exchange (ETDEWEB)

    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.

  10. Thermodynamic Properties of Actinides and Actinide Compounds

    Science.gov (United States)

    Konings, Rudy J. M.; Morss, Lester R.; Fuger, Jean

    The necessity of obtaining accurate thermodynamic quantities for the actinide elements and their compounds was recognized at the outset of the Manhattan Project, when a dedicated team of scientists and engineers initiated the program to exploit nuclear energy for military purposes. Since the end of World War II, both fundamental and applied objectives have motivated a great deal of further study of actinide thermodynamics. This chapter brings together many research papers and critical reviews on this subject. It also seeks to assess, to systematize, and to predict important properties of the actinide elements, ions, and compounds, especially for species in which there is significant interest and for which there is an experimental basis for the prediction.

  11. Advances in computational actinide chemistry in China

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dongqi; Wu, Jingyi; Chai, Zhifang [Chinese Academy of Sciences, Beijing (China). Multidisciplinary Initiative Center; Su, Jing [Chinese Academy of Sciences, Shanghai (China). Div. of Nuclear Materials Science and Engineering; Li, Jun [Tsinghua Univ., Beijing (China). Dept. of Chemistry and Laboratory of Organic Optoelectronics and Molecular Engineering

    2014-04-01

    The advances in computational actinide chemistry made in China are reviewed. Several areas relevant to chemistry of actinides in gas, liquid, and solid phases have been explored. However, we limit the scope to selected contributions in the chemistry of molecular actinide systems in gas and liquid phases. These studies may be classified into two categories: treatment of relativistic effects, which cover the development of two- and four-component Hamiltonians and the optimization of relativistic pseudopotentials, and the applications of theoretical methods in actinide chemistry. The applications include (1) the electronic structures of actinocene, noble gas complexes, An-C multiple bonding compounds, uranyl and its isoelectronic species, fluorides and oxides, molecular systems with metal-metal bonding in their isolated forms (U{sub 2}, Pu{sub 2}) and in fullerene (U{sub 2} rate at C{sub 60}), and the excited states of actinide complexes; (2) chemical reactions, including oxidation, hydrolysis of UF{sub 6}, ligand exchange, reactivities of thorium oxo and sulfido metallocenes, CO{sub 2}/CS{sub 2} functionalization promoted by trivalent uranium complex; and (3) migration of actinides in the environment. A future outlook is discussed. (orig.)

  12. Solid state synthesis and sintering of monazite-type ceramics: application to minor actinides conditioning; Synthese par voie solide et frittage de ceramiques a structure monazite. Application au conditionnement des actinides mineurs

    Energy Technology Data Exchange (ETDEWEB)

    Bregiroux, D

    2005-11-15

    In the framework of the French law of 1991 concerning the nuclear waste management, several studies are undertaken to develop specific crystalline conditioning matrices. Monazite, a rare earth (TR{sup 3+}) orthophosphate with a general formula TR{sup 3+}PO{sub 4}, is a natural mineral containing significant amount of thorium and uranium. Monazite has been proposed as a host matrix for the minor actinides (Np, Am and Cm) specific conditioning, thanks to its high resistance to self irradiation and its low solubility. Its is now of prime importance to check the conservation of these properties on synthesized materials, which implies to master all the stages of the elaboration process, from the powder synthesis to the sintering of controlled microstructure pellets. This work can be divided into two main parts: The first part deals with the synthesis by high temperature solid state route of TR{sup 3+}PO{sub 4} powders (with TR{sup 3+} = La{sup 3+} to Gd{sup 3+}, Pu{sup 3+} and Am{sup 3+}). The chemical reactions occurring during the firing of starting reagents are described in the case of monazite with only one or several cations. From these results, a protocol of synthesis is described. The incorporation of tetravalent cations (Ce{sup 4+}, U{sup 4+}, Pu{sup 4+}) in the monazite structure was also studied. The second part of the present work deals with the elaboration of controlled density and microstructure monazite pellets and their related mechanical and thermal properties. The study of crushing and sintering is presented. For the first time, experimental results are confronted with theoretical models in order to deduce the densification and grain growth mechanisms. By the comprehension of the various physicochemical phenomena occurring during the various stages of the monazite pellets elaboration process (powder synthesis, crushing, sintering...), this work allowed the development of a protocol of elaboration of controlled microstructure monazite TR{sup 3+}PO{sub 4

  13. Investigation of the complexation and the migration of actinides and non-radioactive substances with humic acids under geogenic conditions. Complexation of humic acids with actinides in the oxidation state IV Th, U, Np

    International Nuclear Information System (INIS)

    Sachs, S.; Schmeide, K.; Brendler, V.; Krepelova, A.; Mibus, J.; Geipel, G.; Heise, K.H.; Bernhard, G.

    2004-03-01

    Objective of this project was the study of basic interaction and migration processes of actinides in the environment in presence of humic acids (HA). To obtain more basic knowledge on these interaction processes synthetic HA with specific functional properties as well as 14 C-labeled HA were synthesized and applied in comparison to the natural HA Aldrich. One focus of the work was on the synthesis of HA with distinct redox functionalities. The obtained synthetic products that are characterized by significantly higher Fe(III) redox capacities than Aldrich HA were applied to study the redox properties of HA and the redox stability of U(VI) humate complexes. It was confirmed that phenolic OH groups play an important role for the redox properties of HA. However, the results indicate that there are also other processes than the single oxidation of phenolic OH groups and/or other functional groups contributing to the redox behavior of HA. A first direct-spectroscopic proof for the reduction of U(VI) by synthetic HA with distinct redox functionality was obtained. The complexation behavior of synthetic and natural HA with actinides (Th, Np, Pu) was studied. Structural parameters of Pu(III), Th(IV), Np(IV) and Np(V) humates were determined by X-ray absorption spectroscopy (XAS). The results show that carboxylate groups dominate the interaction between HA and actinide ions. These are predominant monodentately bound. The influence of phenolic OH groups on the Np(V) complexation by HA was studied with modified HA (blocked phenolic OH groups). The blocking of phenolic OH groups induces a decrease of the number of maximal available complexing sites of HA, whereas complex stability constant and Np(V) near-neighbor surrounding are not affected. The effects of HA on the sorption and migration behavior of actinides was studied in batch and column experiments. Th(IV) sorption onto quartz and Np(V) sorption onto granite and its mineral constituents are affected by the pH value and the

  14. Investigation of the complexation and the migration of actinides and non-radioactive substances with humic acids under geogenic conditions. Complexation of humic acids with actinides in the ocidation state IV Th, U, Np

    Energy Technology Data Exchange (ETDEWEB)

    Sachs, S.; Schmeide, K.; Brendler, V.; Krepelova, A.; Mibus, J.; Geipel, G.; Heise, K.H.; Bernhard, G.

    2004-03-01

    Objective of this project was the study of basic interaction and migration processes of actinides in the environment in presence of humic acids (HA). To obtain more basic knowledge on these interaction processes synthetic HA with specific functional properties as well as {sup 14}C-labeled HA were synthesized and applied in comparison to the natural HA Aldrich. One focus of the work was on the synthesis of HA with distinct redox functionalities. The obtained synthetic products that are characterized by significantly higher Fe(III) redox capacities than Aldrich HA were applied to study the redox properties of HA and the redox stability of U(VI) humate complexes. It was confirmed that phenolic OH groups play an important role for the redox properties of HA. However, the results indicate that there are also other processes than the single oxidation of phenolic OH groups and/or other functional groups contributing to the redox behavior of HA. A first direct-spectroscopic proof for the reduction of U(VI) by synthetic HA with distinct redox functionality was obtained. The complexation behavior of synthetic and natural HA with actinides (Th, Np, Pu) was studied. Structural parameters of Pu(III), Th(IV), Np(IV) and Np(V) humates were determined by X-ray absorption spectroscopy (XAS). The results show that carboxylate groups dominate the interaction between HA and actinide ions. These are predominant monodentately bound. The influence of phenolic OH groups on the Np(V) complexation by HA was studied with modified HA (blocked phenolic OH groups). The blocking of phenolic OH groups induces a decrease of the number of maximal available complexing sites of HA, whereas complex stability constant and Np(V) near-neighbor surrounding are not affected. The effects of HA on the sorption and migration behavior of actinides was studied in batch and column experiments. Th(IV) sorption onto quartz and Np(V) sorption onto granite and its mineral constituents are affected by the pH value

  15. Schedules of Controlled Substances: Temporary Placement of Six Synthetic Cannabinoids (5F-ADB, 5F-AMB, 5F-APINACA, ADB-FUBINACA, MDMB-

    Science.gov (United States)

    2016-12-21

    The Administrator of the Drug Enforcement Administration is issuing this notice of intent to temporarily schedule six synthetic cannabinoids: methyl 2-(1-(5-fluoropentyl)-1H-indazole-3-carboxamido)-3,3-dimethylbutanoate [5F-ADB; 5F-MDMB-PINACA]; methyl 2-(1-(5-fluoropentyl)-1H-indazole-3-carboxamido)-3-methylbutanoate [5F-AMB]; N-(adamantan-1-yl)-1-(5-fluoropentyl)-1H-indazole-3-carboxamide [5F-APINACA, 5F-AKB48]; N-(1-amino-3,3-dimethyl-1-oxobutan-2-yl)-1-(4-fluorobenzyl)-1H-indazole-3-carboxamide [ADB-FUBINACA]; methyl 2-(1-(cyclohexylmethyl)-1H-indole-3-carboxamido)-3,3-dimethylbutanoate [MDMB-CHMICA, MMB-CHMINACA] and methyl 2-(1-(4-fluorobenzyl)-1H-indazole-3-carboxamido)-3,3-dimethylbutanoate [MDMB-FUBINACA], into schedule I pursuant to the temporary scheduling provisions of the Controlled Substances Act (CSA). This action is based on a finding by the Administrator that the placement of these synthetic cannabinoids into schedule I of the Controlled Substances Act is necessary to avoid an imminent hazard to the public safety. Any final order will impose the administrative, civil, and criminal sanctions and regulatory controls applicable to schedule I substances under the Controlled Substances Act on the manufacture, distribution, possession, importation, exportation of, and research and conduct with, instructional activities of these synthetic cannabinoids.

  16. Actinide science. Fundamental and environmental aspects

    International Nuclear Information System (INIS)

    Choppin, Gregory R.

    2005-01-01

    Nuclear test explosions and reactor wastes have deposited an estimated 16x10 15 Bq of plutonium into the world's aquatic systems. However, plutonium concentration in open ocean waters is orders of magnitude less, indicating that most of the plutonium is quite insolvable in marine waters and has been incorporated into sediments. Actinide ions in waters often are not in a state of thermodynamic equilibrium and their solubility and migration behavior is related to the form in which the nuclides were introduced into the aquatic system. Actinide solubility depends on such factors as pH(hydrolysis), E H (oxidation state), reaction with complexants (e.g. carbonate, phosphate, humic acid, etc.) sorption to surfaces of minerals and/or colloids, etc., in the water. The most significant of these variables is the oxidation sate of the metal ion. The simultaneous presence of more than one oxidation state for some actinides (e.g. plutonium) in a solution complicates actinide environmental behavior. Both Np(V)O 2 + and Pu(V)O 2 + , the most significant soluble states in natural oxic waters are relatively noncomplexing and resistant to hydrolysis and subsequent precipitation but can undergo reduction to the Pu(IV) oxidation state with its different elemental behavior. The solubility of NpO 2 + can be as high as 10 -4 M while that of PuO 2 + is more limited by reduction to the insoluble tetravalent species, Pu(OH) 4 , (pK SP - 56). The net solubility of hexavalent UO 2 2+ in sea water is also limited by hydrolysis; however, it has a relatively high concentration due to formation of carbonate complexes. The insoluble trivalent americium hydroxocarbonate, Am(CO) 3 (OH), is the limiting species for the solubility of Am(III) in sea water. Thorium is found exclusively as the tetravalent species and its solubility is limited by the formation of quite insoluble Th(OH) 4 . The chemistry of actinide ions in the environment is reviewed to show the spectrum of reactions that can occur in

  17. PRODUCTION OF ACTINIDE METAL

    Science.gov (United States)

    Knighton, J.B.

    1963-11-01

    A process of reducing actinide oxide to the metal with magnesium-zinc alloy in a flux of 5 mole% of magnesium fluoride and 95 mole% of magnesium chloride plus lithium, sodium, potassium, calcium, strontium, or barium chloride is presented. The flux contains at least 14 mole% of magnesium cation at 600-- 900 deg C in air. The formed magnesium-zinc-actinide alloy is separated from the magnesium-oxide-containing flux. (AEC)

  18. Superconductivity in the actinides

    International Nuclear Information System (INIS)

    Smith, J.L.; Lawson, A.C.

    1985-01-01

    The trends in the occurrence of superconductivity in actinide materials are discussed. Most of them seem to show simple transition metal behavior. However, the superconductivity of americium proves that the f electrons are localized in that element and that ''actinides'' is the correct name for this row of elements. Recently the superconductivity of UBe 13 and UPt 3 has been shown to be extremely unusual, and these compounds fall in the new class of compounds now known as heavy fermion materials

  19. Minor actinide transmutation using minor actinide burner reactors

    International Nuclear Information System (INIS)

    Mukaiyama, T.; Yoshida, H.; Gunji, Y.

    1991-01-01

    The concept of minor actinide burner reactor is proposed as an efficient way to transmute long-lived minor actinides in order to ease the burden of high-level radioactive waste disposal problem. Conceptual design study of minor actinide burner reactors was performed to obtain a reactor model with very hard neutron spectrum and very high neutron flux in which minor actinides can be fissioned efficiently. Two models of burner reactors were obtained, one with metal fuel core and the other with particle fuel core. Minor actinide transmutation by the actinide burner reactors is compared with that by power reactors from both the reactor physics and fuel cycle facilities view point. (author)

  20. Subsurface Biogeochemistry of Actinides

    Energy Technology Data Exchange (ETDEWEB)

    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).

  1. Dialkyldithiophosphoric acids - chemical properties and 5f and 4f elements ions extraction

    International Nuclear Information System (INIS)

    Pattee, D.

    1987-09-01

    This work is a contribution to the study of the properties of the dialkyldithiophosphoric acids and of the extraction of the 4f and 5f ions from weakly acidic nitrate and phosphate media. Following a complete bibliographic study, synthesis and purification of the di-2-ethylhexyl-dithiophosphoric acid (HDEHDTP) is studied. It is identified with chemical methods and spectroscopic methods (I.R., N.M.R., V.P.C.); its by products, the di-2-ethylhexyl (monothio) phosphoric acids (HDEHTP, HDEHP) are also identified and characterized. Stability against hydrolysis and radiolysis is determined. The extractive properties are studied for the 4f and 5f ions. The presence of a sulfur donor atom in HDEHDTP makes it inefficient for the extraction of trivalent lanthanides and actinides but brings out a certain selectivity for americium. For HDEHTP, the presence of an oxygen donor atom rubs out any selectivity and the extraction constants are greater. Selectivity of HDEHDTP is increased by TBP (tri-n-butylphosphate) in synergistic mixtures. The mechanism of extraction of hexavalent uranium from phosphoric medium is elucidated. A model is developed by NMR for the micellisation of the sodium salts of HDEHDTP, HDEHTP and HDEHP, and extrapolated it to the trivalent rare earth salts of the acids. The structures are verified by light scattering and low angle X-ray diffraction [fr

  2. The inverse-trans-influence in tetravalent lanthanide and actinide bis(carbene) complexes

    Science.gov (United States)

    Gregson, Matthew; Lu, Erli; Mills, David P.; Tuna, Floriana; McInnes, Eric J. L.; Hennig, Christoph; Scheinost, Andreas C.; McMaster, Jonathan; Lewis, William; Blake, Alexander J.; Kerridge, Andrew; Liddle, Stephen T.

    2017-02-01

    Across the periodic table the trans-influence operates, whereby tightly bonded ligands selectively lengthen mutually trans metal-ligand bonds. Conversely, in high oxidation state actinide complexes the inverse-trans-influence operates, where normally cis strongly donating ligands instead reside trans and actually reinforce each other. However, because the inverse-trans-influence is restricted to high-valent actinyls and a few uranium(V/VI) complexes, it has had limited scope in an area with few unifying rules. Here we report tetravalent cerium, uranium and thorium bis(carbene) complexes with trans C=M=C cores where experimental and theoretical data suggest the presence of an inverse-trans-influence. Studies of hypothetical praseodymium(IV) and terbium(IV) analogues suggest the inverse-trans-influence may extend to these ions but it also diminishes significantly as the 4f orbitals are populated. This work suggests that the inverse-trans-influence may occur beyond high oxidation state 5f metals and hence could encompass mid-range oxidation state actinides and lanthanides. Thus, the inverse-trans-influence might be a more general f-block principle.

  3. Actinide colloid generation in groundwater

    International Nuclear Information System (INIS)

    Kim, J.I.

    1990-05-01

    The progress made in the investigation of actinide colloid generation in groundwaters is summarized and discussed with particular examples relevant to an understanding of the migration behaviour of actinides in natural aquifer systems. The first part deals with the characterization of colloids: groundwater colloids, actinide real-colloids and actinide pseudocolloids. The second part concentrates on the generation processes and migration behaviour of actinide pseudocolloids, which are discussed with some notable experimental examples. Importance is stressed more on the chemical aspects of the actinide colloid generation in groundwater. This work is a contribution to the CEC project MIRAGE II, particularly, to research area: complexation and colloids. (orig.)

  4. Study of actinide paramagnetism in solution

    International Nuclear Information System (INIS)

    Autillo, Matthieu

    2015-01-01

    The physiochemical properties of actinide (An) solutions are still difficult to explain, particularly the behavioral differences between An(III) and Ln(III). The study of actinide paramagnetic behavior may be a 'simple' method to analyze the electronic properties of actinide elements and to obtain information on the ligand-actinide interaction. The objective of this PhD thesis is to understand the paramagnetic properties of these elements by magnetic susceptibility measurements and chemical shift studies. Studies on actinide electronic properties at various oxidation states in solution were carried out by magnetic susceptibility measurements in solution according to the Evans method. Unlike Ln(III) elements, there is no specific theory describing the magnetic properties of these ions in solution. To obtain accurate data, the influence of experimental measurement technique and radioactivity of these elements was analyzed. Then, to describe the electronic structure of their low energy states, the experimental results were complemented with quantum chemical calculations from which the influence of the ligand field was studied. Finally, these interpretations were applied to better understand the variations in the magnetic properties of actinide cations in chloride and nitrate media. Information about ligand-actinide interactions may be determined from an NMR chemical shift study of actinide complexes. Indeed, modifications induced by a paramagnetic complex can be separated into two components. The first component, a Fermi contact contribution (δ_c) is related to the degree of covalency in coordination bonds with the actinide ions and the second, a dipolar contribution (δ_p_c) is related to the structure of the complex. The paramagnetic induced shift can be used only if we can isolate these two terms. To achieve this study on actinide elements, we chose to work with the complexes of dipicolinic acid (DPA). Firstly, to characterize the geometrical parameters, a

  5. Actinide isotopic analysis systems

    International Nuclear Information System (INIS)

    Koenig, Z.M.; Ruhter, W.D.; Gunnink, R.

    1990-01-01

    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

  6. Band structure studies of actinide systems

    International Nuclear Information System (INIS)

    Koelling, D.D.

    1976-01-01

    The nature of the f-orbitals in an actinide system plays a crucial role in determining the electronic properties. It has long been realized that when the actinide separation is small enough for the f-orbitals to interact directly, the system will exhibit itinerant electron properties: an absence of local moment due to the f-orbitals and sometimes even superconductivity. However, a number of systems with the larger actinide separation that should imply local moment behavior also exhibit intinerant properties. Such systems (URh 3 , UIr 3 , UGe 3 , UC) were examined to learn something about the other f-interactions. A preliminary observation made is that there is apparently a very large and ansiotropic mass enhancement in these systems. There is very good reason to believe that this is not solely due to large electron--electron correlations but to a large electron--phonon interaction as well. These features of the ''non-magnetic'', large actinide separation systems are discussed in light of our results to date. Finally, the results of some recent molecular calculations on actinide hexafluorides are used to illustrate the shielding effects on the intra-atomic Coulomb term U/sub f-f/ which would appear in any attempt to study the formation of local moments. As one becomes interested in materials for which a band structure is no longer an adequate model, this screened U/sub ff/ is the significant parameter and efforts must be made to evaluate it in solid state systems

  7. A worldwide perspective on actinide burning

    International Nuclear Information System (INIS)

    Burch, W.D.

    1991-01-01

    Worldwide interest has been evident over the past few years in reexamining the merits of recovering the actinides from spent light-water reactor (LWR) fuel and transmuting them in fast reactors to reduce hazards in geologic repositories. This paper will summarize some of the recent activities in this field. Several countries are embarked on programs of reprocessing and vitrification of present wastes, from which removal of the actinides is largely precluded. The United States is assessing the ideas related to the fast reactor program and the potential application to defense wastes. 18 refs., 2 figs

  8. Actinide and fission product separation and transmutation

    Energy Technology Data Exchange (ETDEWEB)

    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.)

  9. Actinide distribution in the human skeleton

    International Nuclear Information System (INIS)

    Kathren, R.L.; McInroy, J.F.; Swint, M.J.

    1985-05-01

    Radiochemical analysis of two half skeletons donated to the United States Transuranium Registry, one from an individual with an occupationally incurred deposition of 241 Am and the other with a deposition of 239 Pu, revealed an inverse linear relationship between the concentration of actinide in the bone ash and the fraction of ash. Two distinct relationships were noted, one for the cranium and the other for the remainder of the skeleton. The results suggest that the actinide content of the skeleton as a whole, Q, can be obtained with an uncertainty of +-50% from analysis of a single sample of any bone (except the cranium) by Q = [(830 C/sub sample/)/(0.61 - f/sub sample/)], in which C/sub sample/ refers to the actinide content per g of ash and f/sub sample/ the fraction of ash (i.e., ratio of dry to wet weight) in the sample. 5 figs., 3 tabs

  10. Research on Actinides in Nuclear Fuel Cycles

    International Nuclear Information System (INIS)

    Song, Kyu Seok; Park, Yong Joon; Cho, Young Hwan

    2010-04-01

    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

  11. Research on Actinides in Nuclear Fuel Cycles

    Energy Technology Data Exchange (ETDEWEB)

    Song, Kyu Seok; Park, Yong Joon; Cho, Young Hwan

    2010-04-15

    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

  12. The Properties of Trilaurylmethylammonium Nitrate as an Extractant for Trivalent Actinides. RCN Report

    International Nuclear Information System (INIS)

    Ooyen, J. van

    1970-03-01

    The concept of the group of the actinide elements as a f-type transition series within the periodic system was first launched by G.T. Seaborg in 1944]. In this transition series the filling up of the 5 f electron shell would cause a close similarity with the lanthanide series. This proved to be a very fruitful hypothesis in the prediction of the properties of the new elements americium and curium that soon were discovered. The new hypothesis necessitated a shift of the accepted ideas concerning the place of the elements thorium, protactinium and uranium in the periodic table. In fact, the chemistry of these elements had never been considered to be so closely parallel to that of the lanthanides. On the contrary, the trend in the stability of the oxidation states had been interpreted to indicate that these elements would belong to group IVA, VA and VIA respectively. It is undeniable that there are marked differences in oxidation states between the lanthanide elements and the first six elements of the actinide series. However, physical and chemical investigations both of the newly discovered elements and the elements actinium to uranium disclosed many resemblances with the lanthanides that had not been noticed before in this group. The actinide elements - and more in particular the transuranium elements - have been the subject of a number of monographs covering the discovery, the synthesis, the systematics, the chemistry, and (or) the nuclear properties of these elements. It is for this reason that the scope of the following sections in this chapter will be limited to a summary of the chemistry in sofar as it is relevant to the investigations described in the following chapters, viz., the properties of the elements in aqueous systems and more in particular in those systems containing nitrate ions

  13. Actinide nanoparticle research

    International Nuclear Information System (INIS)

    Kalmykov, Stepan N.; Denecke, Melissa A.

    2011-01-01

    This is the first book to cover actinide nano research. It is of interest both for fundamental research into the chemistry and physics of f-block elements as well as for applied researchers such as those studying the long-term safety of nuclear waste disposal and developing remediation strategies. The authors cover important issues of the formation of actinide nano-particles, their properties and structure, environmental behavior of colloids and nanoparticles related to the safe disposal of nuclear wastes, modeling and advanced methods of characterization at the nano-scale. (orig.)

  14. Radiochemistry and actinide chemistry

    International Nuclear Information System (INIS)

    Guillaumont, R.; Peneloux, A.

    1989-01-01

    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 10 12 , 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

  15. The electronic structure of the lanthanides and actinides, a comparison

    International Nuclear Information System (INIS)

    Edelstein, N.M.

    1998-01-01

    Full text: Optical spectra of the two f-element series (the lanthanides and actinides) are comparable in many respects. For the trivalent ions isolated in single crystals, both series exhibit rich, narrow line spectra. These data can be analysed in terms of a parametric model based on a free-ion Hamiltonian plus the addition of a crystal field Hamiltonian. For most systems the agreement between the calculated and experimental energy levels is quite good. In the actinide series there appears to be a correlation between the magnitude of the crystal field and the inadequacy of the fits. The early actinides exhibit multiple oxidation states for which there is no precedent in the lanthanide series. The parametric model mentioned earlier has been utilized for some tetravalent actinide systems with reasonably good results. A selective survey of results describing the similarities and differences of various lanthanide and actinide systems will be given

  16. Actinide-Aluminate Speciation in Alkaline Radioactive Waste

    International Nuclear Information System (INIS)

    Clark, David L.; Fedosseev, Alexander M.

    2001-01-01

    Investigation of behavior of actinides in alkaline media containing AL(III) showed that no aluminate complexes of actinides in oxidation states (IIII-VIII) were formed in alkaline solutions. At alkaline precipitation IPH (10-14) of actinides in presence of AL(III) formation of aluminate compounds is not observed. However, in precipitates contained actinides (IIV)<(VI), and to a lesser degree actinides (III), some interference of components takes place that is reflected in change of solid phase properties in comparison with pure components or their mechanical mixture. The interference decreases with rise of precipitation PH and at PH 14 is exhibited very feebly. In the case of NP(VII) the individual compound with AL(III) is obtained, however it is not aluminate of neptunium(VII), but neptunate of aluminium(III) similar to neptunates of other metals obtained earlier

  17. Imaging the Formation of High-Energy Dispersion Anomalies in the Actinide UCoGa_{5}

    Directory of Open Access Journals (Sweden)

    Tanmoy Das

    2012-11-01

    Full Text Available We use angle-resolved photoemission spectroscopy to image the emergence of substantial dispersion and spectral-weight anomalies in the electronic renormalization of the actinide compound UCoGa_{5} that was presumed to belong to a conventional Fermi-liquid family. Kinks or abrupt breaks in the slope of the quasiparticle dispersion are detected both at low (approximately 130 meV and high (approximately 1 eV binding energies below the Fermi energy, ruling out any significant contribution of phonons. We perform numerical calculations to demonstrate that the anomalies are adequately described by coupling between itinerant fermions and spin fluctuations arising from the particle-hole continuum of the spin-orbit-split 5f states of uranium. These anomalies resemble the “waterfall” phenomenon of the high-temperature copper-oxide superconductors, suggesting that spin fluctuations are a generic route toward multiform electronic phases in correlated materials as different as high-temperature superconductors and actinides.

  18. ANALYSIS OF THE TANK 5F FINAL CHARACTERIZATION SAMPLES-2011

    Energy Technology Data Exchange (ETDEWEB)

    Oji, L.; Diprete, D.; Coleman, C.; Hay, M.

    2012-08-03

    The Savannah River National Laboratory (SRNL) was requested by SRR to provide sample preparation and analysis of the Tank 5F final characterization samples to determine the residual tank inventory prior to grouting. Two types of samples were collected and delivered to SRNL: floor samples across the tank and subsurface samples from mounds near risers 1 and 5 of Tank 5F. These samples were taken from Tank 5F between January and March 2011. These samples from individual locations in the tank (nine floor samples and six mound Tank 5F samples) were each homogenized and combined in a given proportion into 3 distinct composite samples to mimic the average composition in the entire tank. These Tank 5F composite samples were analyzed for radiological, chemical and elemental components. Additional measurements performed on the Tank 5F composite samples include bulk density and water leaching of the solids to account for water soluble species. With analyses for certain challenging radionuclides as the exception, all composite Tank 5F samples were analyzed and reported in triplicate. The target detection limits for isotopes analyzed were based on customer desired detection limits as specified in the technical task request documents. SRNL developed new methodologies to meet these target detection limits and provide data for the extensive suite of components. While many of the target detection limits were met for the species characterized for Tank 5F, as specified in the technical task request, some were not met. In a few cases, the relatively high levels of radioactive species of the same element or a chemically similar element precluded the ability to measure some isotopes to low levels. The Technical Task Request allows that while the analyses of these isotopes is needed, meeting the detection limits for these isotopes is a lower priority than meeting detection limits for the other specified isotopes. The isotopes whose detection limits were not met in all cases included the

  19. Analysis Of The Tank 5F Final Characterization Samples-2011

    Energy Technology Data Exchange (ETDEWEB)

    Oji, L. N.; Diprete, D.; Coleman, C. J.; Hay, M. S.

    2012-09-27

    The Savannah River National Laboratory (SRNL) was requested by SRR to provide sample preparation and analysis of the Tank 5F final characterization samples to determine the residual tank inventory prior to grouting. Two types of samples were collected and delivered to SRNL: floor samples across the tank and subsurface samples from mounds near risers 1 and 5 of Tank 5F. These samples were taken from Tank 5F between January and March 2011. These samples from individual locations in the tank (nine floor samples and six mound Tank 5F samples) were each homogenized and combined in a given proportion into 3 distinct composite samples to mimic the average composition in the entire tank. These Tank 5F composite samples were analyzed for radiological, chemical and elemental components. Additional measurements performed on the Tank 5F composite samples include bulk density and water leaching of the solids to account for water soluble species. With analyses for certain challenging radionuclides as the exception, all composite Tank 5F samples were analyzed and reported in triplicate. The target detection limits for isotopes analyzed were based on customer desired detection limits as specified in the technical task request documents. SRNL developed new methodologies to meet these target detection limits and provide data for the extensive suite of components. While many of the target detection limits were met for the species characterized for Tank 5F, as specified in the technical task request, some were not met. In a few cases, the relatively high levels of radioactive species of the same element or a chemically similar element precluded the ability to measure some isotopes to low levels. The Technical Task Request allows that while the analyses of these isotopes is needed, meeting the detection limits for these isotopes is a lower priority than meeting detection limits for the other specified isotopes. The isotopes whose detection limits were not met in all cases included the

  20. Actinide separative chemistry

    International Nuclear Information System (INIS)

    Boullis, B.

    2004-01-01

    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

  1. Anchor balloons assisted deep intubation of 5F catheters for ...

    African Journals Online (AJOL)

    2015-07-24

    Jul 24, 2015 ... However, cardiologists still encounter some difficult scenarios such as variant coronary artery origins, severely calcified and ... Medical University, 300, Guangzhou Road, Nanjing,. Jiangsu .... (l) The ST segment elevated while the 5F catheter was inserted into the proximal left anterior descending artery d.

  2. Actinide oxide photodiode and nuclear battery

    Energy Technology Data Exchange (ETDEWEB)

    Sykora, Milan; Usov, Igor

    2017-12-05

    Photodiodes and nuclear batteries may utilize actinide oxides, such a uranium oxide. An actinide oxide photodiode may include a first actinide oxide layer and a second actinide oxide layer deposited on the first actinide oxide layer. The first actinide oxide layer may be n-doped or p-doped. The second actinide oxide layer may be p-doped when the first actinide oxide layer is n-doped, and the second actinide oxide layer may be n-doped when the first actinide oxide layer is p-doped. The first actinide oxide layer and the second actinide oxide layer may form a p/n junction therebetween. Photodiodes including actinide oxides are better light absorbers, can be used in thinner films, and are more thermally stable than silicon, germanium, and gallium arsenide.

  3. MOLECULAR SPECTROSCPY AND REACTIONS OF ACTINIDES IN THE GAS PHASE AND CRYOGENIC MATRICES

    Energy Technology Data Exchange (ETDEWEB)

    Heaven, Michael C.; Gibson, John K.; Marcalo, Joaquim

    2009-02-01

    In this chapter we review the spectroscopic data for actinide molecules and the reaction dynamics for atomic and molecular actinides that have been examined in the gas phase or in inert cryogenic matrices. The motivation for this type of investigation is that physical properties and reactions can be studied in the absence of external perturbations (gas phase) or under minimally perturbing conditions (cryogenic matrices). This information can be compared directly with the results from high-level theoretical models. The interplay between experiment and theory is critically important for advancing our understanding of actinide chemistry. For example, elucidation of the role of the 5f electrons in bonding and reactivity can only be achieved through the application of experimentally verified theoretical models. Theoretical calculations for the actinides are challenging due the large numbers of electrons that must be treated explicitly and the presence of strong relativistic effects. This topic has been reviewed in depth in Chapter 17 of this series. One of the goals of the experimental work described in this chapter has been to provide benchmark data that can be used to evaluate both empirical and ab initio theoretical models. While gas-phase data are the most suitable for comparison with theoretical calculations, there are technical difficulties entailed in generating workable densities of gas-phase actinide molecules that have limited the range of species that have been characterized. Many of the compounds of interest are refractory, and problems associated with the use of high temperature vapors have complicated measurements of spectra, ionization energies, and reactions. One approach that has proved to be especially valuable in overcoming this difficulty has been the use of pulsed laser ablation to generate plumes of vapor from refractory actinide-containing materials. The vapor is entrained in an inert gas, which can be used to cool the actinide species to room

  4. Self-interaction corrected local spin density calculations of actinides

    DEFF Research Database (Denmark)

    Petit, Leon; Svane, Axel; Szotek, Z

    2010-01-01

    We use the self-interaction corrected local spin-density approximation in order to describe localization-delocalization phenomena in the strongly correlated actinide materials. Based on total energy considerations, the methodology enables us to predict the ground-state valency configuration...... of the actinide ions in these compounds from first principles. Here we review a number of applications, ranging from electronic structure calculations of actinide metals, nitrides and carbides to the behaviour under pressure of intermetallics, and O vacancies in PuO2....

  5. The degree of 5f electron localization in URu2Si2: electron energy-loss spectroscopy and spin-orbit sum rule analysis

    Energy Technology Data Exchange (ETDEWEB)

    Jeffries, J R; Moore, K T; Butch, N P; Maple, M B

    2010-05-19

    We examine the degree of 5f electron localization in URu{sub 2}Si{sub 2} using spin-orbit sum rule analysis of the U N{sub 4,5} (4d {yields} 5f) edge. When compared to {alpha}-U metal, US, USe, and UTe, which have increasing localization of the 5f states, we find that the 5f states of URu{sub 2}Si{sub 2} are more localized, although not entirely. Spin-orbit analysis shows that intermediate coupling is the correct angular momentum coupling mechanism for URu{sub 2}Si{sub 2} when the 5f electron count is between 2.6 and 2.8. These results have direct ramifications for theoretical assessment of the hidden order state of URu{sub 2}Si{sub 2}, where the degree of localization of the 5f electrons and their contribution to the Fermi surface are critical.

  6. Actinide recycling in reactors

    International Nuclear Information System (INIS)

    Kuesters, H.; Wiese, H.W.; Krieg, B.

    1995-01-01

    The objective is an assessment of the transmutation of long-lived actinides and fission products and the incineration of plutonium for reducing the risk potential of radioactive waste from reactors in comparison to direct waste disposal. The contribution gives an interim account on homogeneous and heterogeneous recycling of 'risk nuclides' in thermal and fast reactors. Important results: - A homogeneous 5 percent admixture of minor actinides (MA) from N4-PWRs to EFR fuel would allow a transmutation not only of the EFR MA, but in addition of the MA from 5 or 6 PWRs of equal power. However, the incineration is restricted by safety considerations. - LWR have only a very low MA incineration potential, due to their disadvantageous neutron capture/fission ratio. - In order to keep the Cm inventory at a low level, it is advantageous to concentrate the Am heterogeneously in particular fuel elements or rods. (orig./HP)

  7. Photochemistry of the actinides

    International Nuclear Information System (INIS)

    Toth, L.M.; Bell, J.T.; Friedman, H.A.

    1979-01-01

    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

  8. Actinide separation chemistry in nuclear waste streams and materials

    International Nuclear Information System (INIS)

    1997-12-01

    The separation of actinide elements from various waste materials, produced either in nuclear fuel cycles or in past nuclear weapons production, represents a significant issue facing developed countries. Improvements in the efficiencies of the separation processes can be expected to occur as a result of better knowledge of the elements in these complex matrices. The Nuclear Science Committee of the OECD/NEA has established a task force of experts in actinide separation chemistry to review current and developing separation techniques and chemical processes. The report consist of eight chapters. In Chapter 1 the importance of actinide separation chemistry in the fields of waste management and its background are summarized.In Chapter 2 the types of waste streams are classified according to their relative importance, by physical form and by source of actinides. The basic data of actinide chemical thermodynamics, such as oxidation states, hydrolysis, complexation, sorption, Gibbs energies of formation, and volatility, were collected and are presented in Chapter 3. Actinide analyses related to separation processes are also mentioned in this chapter. The state of the art of actinide separation chemistry is classified in three groups, including hydrometallurgy, pyrochemical process and process based on fields, and is described in Chapter 4 along with the relationship of kinetics to separations. In Chapter 5 basic chemistry research needs and the inherent limitation on separation processes are discussed. Prioritization of research and development is discussed in Chapter 6 in the context of several attributes of waste management problems. These attributes include: mass or volume of waste; concentration of the actinide in the waste; expected difficulty of treating the wastes; short-term hazard of the waste; long-term hazard of the waste; projected cost of treatment; amount of secondary waste. Based on the priority, recommendations were made for the direction of future research

  9. Actinide separation chemistry in nuclear waste streams and materials

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-01

    The separation of actinide elements from various waste materials, produced either in nuclear fuel cycles or in past nuclear weapons production, represents a significant issue facing developed countries. Improvements in the efficiencies of the separation processes can be expected to occur as a result of better knowledge of the elements in these complex matrices. The Nuclear Science Committee of the OECD/NEA has established a task force of experts in actinide separation chemistry to review current and developing separation techniques and chemical processes. The report consist of eight chapters. In Chapter 1 the importance of actinide separation chemistry in the fields of waste management and its background are summarized.In Chapter 2 the types of waste streams are classified according to their relative importance, by physical form and by source of actinides. The basic data of actinide chemical thermodynamics, such as oxidation states, hydrolysis, complexation, sorption, Gibbs energies of formation, and volatility, were collected and are presented in Chapter 3. Actinide analyses related to separation processes are also mentioned in this chapter. The state of the art of actinide separation chemistry is classified in three groups, including hydrometallurgy, pyrochemical process and process based on fields, and is described in Chapter 4 along with the relationship of kinetics to separations. In Chapter 5 basic chemistry research needs and the inherent limitation on separation processes are discussed. Prioritization of research and development is discussed in Chapter 6 in the context of several attributes of waste management problems. These attributes include: mass or volume of waste; concentration of the actinide in the waste; expected difficulty of treating the wastes; short-term hazard of the waste; long-term hazard of the waste; projected cost of treatment; amount of secondary waste. Based on the priority, recommendations were made for the direction of future research

  10. Analytical chemistry of actinides

    International Nuclear Information System (INIS)

    Chollet, H.; Marty, P.

    2001-01-01

    Different characterization methods specifically applied to the actinides are presented in this review such as ICP/OES (inductively coupled plasma-optical emission spectrometry), ICP/MS (inductively coupled plasma spectroscopy-mass spectrometry), TIMS (thermal ionization-mass spectrometry) and GD/OES (flow discharge optical emission). Molecular absorption spectrometry and capillary electrophoresis are also available to complete the excellent range of analytical tools at our disposal. (authors)

  11. Partitioning and Transmutation of minor actinides

    International Nuclear Information System (INIS)

    Koch, L.; Wellum, R.

    1991-01-01

    The partitioning of minor actinides from spent fuels and their transmutation into short-lived fission products has been the topic of two dedicated meetings organized jointly by the European Commission and the OECD. The conclusion of the last meeting in 1980, in short, was that partitioning and transmutation of minor actinides, especially in fast reactors, seemed possible. However, the incentive, which would be a reduction of the radiological hazard to the public, was too small if long-lived fission products were not included. Furthermore this meeting showed that minor actinide targets or possible nuclear fuels containing minor actinides for transmutation had not yet been developed. The European Institute for Transuranium Elements took up this task and has carried it out as a small activity for several years. Interests expressed recently by an expert meeting of the OECD/NEA (Paris, 25 April 1989), which was initiated by the proposed Japanese project Omega, led us to the conclusion that the present state of knowledge should be looked at in a workshop environment. Since the Japanese proposal within the project Omega is based on a broader approach we needed this evaluation to assess the relevance of our present activity and wanted to identifiy additional studies which might be needed to cover possible future demands from the public. This workshop was therefore organized, and participants active in the field from EC countries, the USA and Japan were invited

  12. Citrate based ''TALSPEAK'' lanthanide-actinide separation process

    International Nuclear Information System (INIS)

    Del Cul, G.D.; Bond, W.D.; Toth, L.M.; Davis, G.D.; Dai, S.; Metcalf, D.H.

    1994-09-01

    The potential hazard posed to future generations by long-lived radionuclides such as the transuranic elements (TRU) is perceived as a major problem associated with the use of nuclear power. TRU wastes have to remain isolated from the environment for ''geological'' periods of time. The costs of building, maintaining, and operating a ''geological TRU repository'' can be very high. Therefore, there are significant economical advantages in segregating the relatively low volume of TRU wastes from other nuclear wastes. The chemical behavior of lanthanides and actinides, 4f and 5f elements respectively, is rather similar. As a consequence, the separation of these two groups is difficult. The ''TALSPEAK'' process (Trivalent Actinide Lanthanide Separations by Phosphorus-reagent Extraction from Aqueous Complexes) is one of the few means available to separate the trivalent actinides from the lanthanides. The method is based on the preferential complexation of the trivalent actinides by an aminopolyacetic acid. Cold experiments showed that by using citric acid the deleterious effects produced by impurities such as zirconium are greatly reduced

  13. Sol-gel chemistry applied to the synthesis of polymetallic oxides including actinides reactivity and structure from solution to solid state; Synthese par voie douce d'oxydes polymetalliques incluant des actinides: reactivite et structure de la solution au solide

    Energy Technology Data Exchange (ETDEWEB)

    Lemonnier, St

    2006-02-15

    Minor actinides transmutation is studied at present in order to reduce the radiotoxicity of nuclear waste and the assessment of its technical feasibility requires specific designed materials. When considering americium, yttria stabilized zirconia (Am{sup III} YII Zriv)Or{sub x} is among the ceramic phases that one which presents the required physico-chemical properties. An innovative synthesis of this mixed oxide by sol-gel process is reported in this manuscript. The main aim of this work is to adjust the reactivity of the different metallic cations in aqueous media using complexing agent, in order to initiate a favourable interaction for a homogeneous elements repartition in the forming solid phase. The originality of the settled synthesis lies on an in-situ formation of a stable and monodisperse nano-particles dispersion in the presence of acetylacetone. The main reaction mechanisms have been identified: the sol stabilisation results from an original interaction between the three compounds (Zrly, trivalent cations and acetylacetone). The sol corresponds to a structured system at the nanometer scale for which zirconium and trivalent cations are homogeneously dispersed, preliminary to the sol-gel transition. Furthermore, preliminary studies were carried out with a view to developing materials. They have demonstrated that numerous innovative and potential applications can be developed by taking advantage of the direct and controlled formation of the sol and by adapting the sol-gel transition. The most illustrating result is the preparation of a sintered pellet with the composition Am0,13Zro,73Yo,0901,89 using this approach. (author)

  14. Actinides: why are they important biologically

    International Nuclear Information System (INIS)

    Durbin, P.W.

    1978-01-01

    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. Application of powerful oxidizers in the synthesis of new high-oxidation state actinide and related species

    International Nuclear Information System (INIS)

    Yeh, S.M.

    1984-11-01

    The fluorinating and oxide scavenging ability of XeF 6 have been studied by bringing XeF 6 into interaction with oxide-fluoride compounds of the third-transition-series elements (W, Re and Os) and uranium, in their highest oxidation states. A + MOF 5 - and A + M 2 O 2 F 9 - (A = K or Cs, M = W or U) were converted to A + MF 7 - by XeF 6 , but the rhenium and osmium compounds, K + ReO 2 F 4 - and XeF 5 + OsO 3 F 3 - , resisted interaction with XeF 6 . Strong interactions between XeF 2 or KrF 2 and the solvent have been observed for their solutions in anhydrous HF. Both XeF 2 and KrF 2 are seen to be effective in breaking up the polymeric (HF)/sub n/ chains. Only weak interactions occur between cations and anions of KrF + AuF 6 - and Kr 2 F 3 + AuF 6 - in HF. The AuF 6 - anions are slightly distorted from O/sub h/ symmetry. Kr 2 F 3 + cations in HF have the same dissymmetric V-shape which occurs in crystalline salts. A low-temperature orthorhombic form, β-ReF 6 + SbF 6 - , a high-temperature rhombohedral form, α-ReF 6 + SbF 6 - , and a ReF 6 + AuF 6 - have been prepared. These compounds possess only kinetic stability at ambient temperature and at approx. 20 0 C are best represented as ReF 6 + ReF 7 MF 6 - MF 5 . Thermochemical energy evaluations indicate that the ionization potential of ReF 6 is 261 kcal mole -1 and that the fluoride-ion affinity of ReF 6 + is -214 kcal mole -1 . This is more exothermal than the corresponding process for IF 6 + (-208 kcal mole -1 ). In contrast, ReOF 5 is shown to be a better fluoro-base than IOF 5 and also is a better base than ReF 7 . ReOF 4 + MF 6 - (M = Sb, Au and As) salts are of higher thermal stability than their ReF 6 + MF 6 - analogues

  16. Spectroscopic properties of tetravalent actinide ions in solids

    International Nuclear Information System (INIS)

    Krupa, J.C.

    1987-01-01

    Optical spectroscopy is a powerful tool to study the electronic structure of an optically active transition ion in the condensed phase media and consequently to study the interactions between the central ion and its environment. The main interactions that are essential for an understanding of the energy level distribution of an f N ion in solids is briefly examined and the deduced free-ion and crystal field parameters for Pa 4+ , U 4+ , Np 4+ are compared to those of the isoelectronic configuration lanthanide ions. At last, the actinide series offers an interesting situation since the 5f electrons in the metals are delocalized in the light actinides and then localized, that sould affect the nature of the chemical bonding in the two parts of the series. Is this trend reflected in the An 4+ spectroscopic parameters

  17. Leaching of actinides from nuclear waste glass: French experience

    International Nuclear Information System (INIS)

    Vernaz, E.Y.; Godon, N.

    1991-01-01

    The activity concentration versus time of a typical LWR glass shows that after 300 years most of the activity is attributable to three actinides (Np, Pu and Am) and to 99 Tc. This activity decreases slowly, and some 50.000 years are necessary before the activity concentration drops to the level of the richest natural ores. This paper reviews the current state of knowledge concerning the kinetics of actinide release from glass subjected to aqueous leaching

  18. Complexes in solution of o-phenanthroline with the ions of 4f and 5f elements at valencies II, III, V, VI

    International Nuclear Information System (INIS)

    Le Marois, Gilles.

    1980-06-01

    Slight differences between the complexation in aqueous solution of 4f and 5f series ions are revealed by the use of a soft, aromatic and chelating ligand of the o-phenanthroline type. Trivalent actinide ions are extrated selectively in the presence of a carboxylic acid. This extraction takes place at high pH and does not require large quantities of salts in aqueous solution, which increase the volume of radioactive wastes for storage. Only the first two o-phenanthroline complexes of these ions are obtained in aqueous solution. Determination of the constants of formation of such complexes shows the stronger affinity of the ligand for actinide ions. An inversion of the usual order of complexation of the different actinide valencies is also observed: pentavalent ions are most complexed than trivalent, o-phenanthroline stabilises actinide ions preferentially because they are more liable to form bonds with delocalised electrons. Finally a slight stabilisation of europium at valency II shows the participation of electrons by back bonding of the metal, due to the strong conjugation of the ligand π electrons [fr

  19. The thermodynamic functions of gaseous actinide elements

    International Nuclear Information System (INIS)

    Rand, M.H.

    1979-01-01

    The actinide gases have large number of unobserved energy states - up to 3 x 10 6 for Pu(g) - which could contribute to the partition function and its derivatives, from which the thermal functions of these gases are calculated. Existing compilations have simply ignored these levels. By making reasonable assumptions as to the distribution of these energy states, their effect on the functions can be calculated. It is concluded that the existing compilations will be inadequate above approximately 2000K. The effect is particularly marked on the heat capacity. For example, when unobserved levels for Pu(g) are included, the heat capacity of Pu(g) reaches a maximum value of more than 12R at 3200K. Similar considerations will apply to the gaseous actinide ions. (orig.) [de

  20. Alternative Chemical Cleaning Methods for High Level Waste Tanks: Actual Waste Testing with SRS Tank 5F Sludge

    Energy Technology Data Exchange (ETDEWEB)

    King, William D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hay, Michael S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-08-30

    Solubility testing with actual High Level Waste tank sludge has been conducted in order to evaluate several alternative chemical cleaning technologies for the dissolution of sludge residuals remaining in the tanks after the exhaustion of mechanical cleaning and sludge sluicing efforts. Tests were conducted with archived Savannah River Site (SRS) radioactive sludge solids that had been retrieved from Tank 5F in order to determine the effectiveness of an optimized, dilute oxalic/nitric acid cleaning reagent toward dissolving the bulk non-radioactive waste components. Solubility tests were performed by direct sludge contact with the oxalic/nitric acid reagent and with sludge that had been pretreated and acidified with dilute nitric acid. For comparison purposes, separate samples were also contacted with pure, concentrated oxalic acid following current baseline tank chemical cleaning methods. One goal of testing with the optimized reagent was to compare the total amounts of oxalic acid and water required for sludge dissolution using the baseline and optimized cleaning methods. A second objective was to compare the two methods with regard to the dissolution of actinide species known to be drivers for SRS tank closure Performance Assessments (PA). Additionally, solubility tests were conducted with Tank 5 sludge using acidic and caustic permanganate-based methods focused on the “targeted” dissolution of actinide species.

  1. Thermal neutron actinide data

    International Nuclear Information System (INIS)

    Tellier, H.

    1992-01-01

    During the 70's, the physicists involved in the cross section measurements for the low energy neutrons were almost exclusively interested in the resonance energy range. The thermal range was considered as sufficiently known. In the beginning of the 80's, reactor physicists had again to deal with the delicate problem of the power reactor temperature coefficient, essentially for the light water reactors. The measured value of the reactivity temperature coefficient does not agree with the computed one. The later is too negative. For obvious safety reasons, it is an important problem which must be solved. Several causes were suggested to explain this discrepancy. Among all these causes, the spectral shift in the thermal energy range seems to be very important. Sensibility calculations shown that this spectral shift is very sensitive to the shape of the neutron cross sections of the actinides for energies below one electron-volt. Consequently, reactor physicists require new and accurate measurements in the thermal and subthermal energy ranges. A part of these new measurement results were recently released and reviewed. The purpose of this study is to complete the preceding review with the new informations which are now available. In reactor physics the major actinides are the fertile nuclei, uranium 238, thorium 232 and plutonium 240 and the fissile nuclei, uranium 233, uranium 235 and plutonium 239. For the fertile nuclei the main datum is the capture cross section, for the fissile nuclei the data of interest are nu-bar, the fission and capture cross sections or a combination of these data such as η or α. In the following sections, we will review the neutron data of the major actinides for the energy below 1 eV

  2. Actinide Separation Demonstration Facility, Tarapur

    International Nuclear Information System (INIS)

    Vishwaraj, I.

    2017-01-01

    Partitioning of minor actinide from high level waste could have a substantial impact in lowering the radio toxicity associated with high level waste as well as it will reduce the burden on geological repository. In Indian context, the partitioned minor actinide could be routed into the fast breeder reactor systems scheduled for commissioning in the near period. The technological breakthrough in solvent development has catalyzed the partitioning programme in India, leading to the setting up and hot commissioning of the Actinide Separation Demonstration Facility (ASDF) at BARC, Tarapur. The engineering scale Actinide Separation Demonstration Facility (ASDF) has been retrofitted in an available radiological hot cell situated adjacent to the Advanced Vitrification Facility (AVS). This location advantage ensures an uninterrupted supply of high-level waste and facilitates the vitrification of the high-level waste after separation of minor actinides

  3. Oxalate Mass Balance During Chemical Cleaning in Tank 5F

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, M.; Fink, S.

    2011-07-08

    The Savannah River Site (SRS) is preparing Tank 5F for closure. The first step in preparing the tank for closure is mechanical sludge removal. Following mechanical sludge removal, SRS performed chemical cleaning with oxalic acid to remove the sludge heel. Personnel are currently assessing the effectiveness of the chemical cleaning to determine whether the tank is ready for closure. SRS personnel collected liquid samples during chemical cleaning and submitted them to Savannah River National Laboratory (SRNL) for analysis. Following chemical cleaning, they collected a solid sample (also known as 'process sample') and submitted it to SRNL for analysis. The authors analyzed these samples to assess the effectiveness of the chemical cleaning process. Analysis of the anions showed the measured oxalate removed from Tank 5F to be approximately 50% of the amount added in the oxalic acid. To close the oxalate mass balance, the author collected solid samples, leached them with nitric acid, and measured the concentration of cations and anions in the leachate.

  4. Actinide AMS at DREAMS

    Energy Technology Data Exchange (ETDEWEB)

    Khojasteh, Nasrin B.; Merchel, Silke; Rugel, Georg; Scharf, Andreas; Ziegenruecker, Rene [HZDR, Dresden (Germany); Pavetich, Stefan [HZDR, Dresden (Germany); ANU, Canberra (Australia)

    2016-07-01

    Radionuclides such as {sup 236}U and {sup 239}Pu were introduced into the environment by atmospheric nuclear weapon tests, reactor accidents (Chernobyl, Fukushima), releases from nuclear reprocessing facilities (Sellafield, La Hague), radioactive waste disposal, and accidents with nuclear devices (Palomares, Thule) [1]. Accelerator Mass Spectrometry (AMS) is the most sensitive method to measure these actinides. The DREsden AMS (DREAMS) facility is located at a 6 MV accelerator, which is shared with ion beam analytics and implantation users, preventing major modifications of the accelerator and magnetic analyzers. DREAMS was originally designed for {sup 10}Be, {sup 26}Al, {sup 36}Cl, {sup 41}Ca, and {sup 129}I. To modify the system for actinide AMS, a Time-of-Flight (TOF) beamline at the high-energy side has been installed and performance tests are on-going. Ion beam and detector simulations are carried out to design a moveable ionization chamber. Especially, the detector window and anode dimensions have to be optimized. This ionization chamber will act as an energy detector of the system and its installation is planned as closely as possible to the stop detector of the TOF beamline for highest detection efficiency.

  5. Rare earths and actinides

    International Nuclear Information System (INIS)

    Coqblin, B.

    1982-01-01

    This paper reviews the different properties of rare-earths and actinides, either as pure metals or as in alloys or compounds. Three different cases are considered: (i) First, in the case of 'normal' rare-earths which are characterized by a valence of 3, we discuss essentially the magnetic ordering, the coexistence between superconductivity and magnetism and the properties of amorphous rare-earth systems. (ii) Second, in the case of 'anomalous' rare-earths, we distinguish between either 'intermediate-valence' systems or 'Kondo' systems. Special emphasis is given to the problems of the 'Kondo lattice' (for compounds such as CeAl 2 ,CeAl 3 or CeB 6 ) or the 'Anderson lattice' (for compounds such as TmSe). The problem of neutron diffraction in these systems is also discussed. (iii) Third, in the case of actinides, we can separate between the d-f hybridized and almost magnetic metals at the beginning of the series and the rare-earth like the metals after americium. (orig.)

  6. Chemistry of the actinide elements. Second edition

    International Nuclear Information System (INIS)

    Katz, J.J.; Seaborg, G.T.; Morss, L.R.

    1987-01-01

    This is an exhaustive, updated discourse on the chemistry of Actinides, Volume 1 contains a systematic coverage of the elements Ac, Th, Pa, U, Np, and Pu, which constitutes Part 1 of the work. The characterization of each element is discussed in terms of its nuclear properties, occurrence, preparation, atomic and metallic properties, chemistry of specific compounds, and solution chemistry. The first part of Volume 2 follows the same format as Volume 1 but is confined to the elements Am, Cm, Bk, Cf, and Es, plus a more condensed coverage of the Transeinsteinium elements (Fm, Md, No, Lw, and 104-109). Part 2 of this volume is devoted to a discussion of the actinide elements in general, with a specific focus on electronic spectra, thermodynamic and magnetic properties, the metallic state, structural chemistry, solution kinetics, organometallic chemistry for σ- and π-bonded compounds, and some concluding remarks on the superheavy elements

  7. Studies of Actinides Reduction on Iron Surfaces by Means of Resonant Inelastic X-ray Scattering

    International Nuclear Information System (INIS)

    Kvashnina, K.O.; Butorin, S.M.; Shuh, D.K.; Ollila, K.; Soroka, I.; Guo, J.-H.; Werme, L.; Nordgren, J.

    2006-01-01

    The interaction of actinides with corroded iron surfaces was studied using resonant inelastic x-ray scattering (RIXS) spectroscopy at actinide 5d edges. RIXS profiles, corresponding to the f-f excitations are found to be very sensitive to the chemical states of actinides in different systems. Our results clearly indicate that U(VI) (as soluble uranyl ion) was reduced to U(IV) in the form of relatively insoluble uranium species, indicating that the iron presence significantly affects the mobility of actinides, creating reducing conditions. Also Np(V) and Pu (VI) in the ground water solution were getting reduced by the iron surface to Np(IV) and Pu (IV) respectively. Studying the reduction of actinides compounds will have an important process controlling the environmental behavior. Using RIXS we have shown that actinides, formed by radiolysis of water in the disposal canister, are likely to be reduced on the inset corrosion products and prevent release from the canister

  8. Separation and preconcentration of actinides from acidic media by extraction chromatography

    International Nuclear Information System (INIS)

    Horwitz, E. Philip; Chiarizia, Renato; Dietz, Mark L.; Diamond, Herbert; Nelson, Donald M.

    1993-01-01

    A systematic examination of the effect of nitric and hydrochloric acid concentrations and of macro levels of selected elements on the sorption of actinide ions by a novel extraction chromatographic resin comprised of a solution of octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide in tri-n-butyl phosphate supported on an inert polymeric substrate is described. Actinide sorption is demonstrated to be most efficient at high (>1 M) nitric acid concentrations, although tetra- and hexavalent actinides are strongly retained even from dilute (e.g., 0.05 M) nitric acid solutions. Macro concentrations of several common anions (e.g., PO 4 3- and SO 4 2- ) or complexing agents (e.g., oxalic acid) are shown not to adversely affect the sorption of trivalent actinides, while reducing the sorption of tetravalents. Such effects, together with oxidation state adjustments, are shown to provide a basis for the sequential elution of individual actinides and for actinide isolation from environmental and biological matrices

  9. Research on the actinide chemistry in Nuclear Fuel Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Song, Kyseok; Park, Yong Joon; Cho, Young Hwan; and others

    2012-04-15

    Fundamental technique to measure chemical behaviors and properties of lanthanide and actinide in radioactive waste is necessary for the development of pryochemical process. First stage, 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 equipments, 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. In the second stage, measurement system for physical properties at pyrochemical process such as viscosity, melting point and conductivity is established, and property database at different compositions of lanthanide and actinide is collected. And, both interactions between elements and properties with different potential are measured at binary composition of actinide-lanthanide in molten salt using electrochemical/spectroscopic integrated measurement system.

  10. ANALYSIS OF SAMPLES FROM TANK 5F CHEMICAL CLEANING

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, M.; Fink, S.

    2011-03-07

    The Savannah River Site (SRS) is preparing Tank 5F for closure. The first step in preparing the tank for closure is mechanical sludge removal. Following mechanical sludge removal, SRS performed chemical cleaning with oxalic acid to remove the sludge heel. Personnel are currently assessing the effectiveness of the chemical cleaning. SRS personnel collected liquid samples during chemical cleaning and submitted them to Savannah River National Laboratory (SRNL) for analysis. Following chemical cleaning, they collected a solid sample (also known as 'process sample') and submitted it to SRNL for analysis. The authors analyzed these samples to assess the effectiveness of the chemical cleaning process. The conclusions from this work are: (1) With the exception of iron, the dissolution of sludge components from Tank 5F agreed with results from the actual waste demonstration performed in 2007. The fraction of iron removed from Tank 5F by chemical cleaning was significantly less than the fraction removed in the SRNL demonstrations. The likely cause of this difference is the high pH following the first oxalic acid strike. (2) Most of the sludge mass remaining in the tank is iron and nickel. (3) The remaining sludge contains approximately 26 kg of barium, 37 kg of chromium, and 37 kg of mercury. (4) Most of the radioactivity remaining in the residual material is beta emitters and {sup 90}Sr. (5) The chemical cleaning removed more than {approx} 90% of the uranium isotopes and {sup 137}Cs. (6) The chemical cleaning removed {approx} 70% of the neptunium, {approx} 83% of the {sup 90}Sr, and {approx} 21% of the {sup 60}Co. (7) The chemical cleaning removed less than 10% of the plutonium, americium, and curium isotopes. (8) The chemical cleaning removed more than 90% of the aluminium, calcium, and sodium from the tank. (9) The cleaning operations removed 61% of lithium, 88% of non-radioactive strontium, and 65% of zirconium. The {sup 90}Sr and non-radioactive strontium were

  11. High resolution X-ray emission spectroscopy: An advanced tool for actinide research

    Science.gov (United States)

    Vitova, T.; Brendebach, B.; Dardenne, K.; Denecke, M. A.; Lebid, A.; Löble, M.; Rothe, J.; Batuk, O. N.; Hormes, J.; Liu, D.; Breher, F.; Geckeis, H.

    2010-03-01

    High resolution X-ray emission spectroscopy (HRXES) is becoming increasingly important for our understanding of electronic and coordination structures. The combination of such information with development of quantum theoretical tools will advance our capability for predicting reactivity and physical behavior especially of 5f elements. HRXES can be used to remove lifetime broadening by registering the partial fluorescence yield emitted by the sample (i.e., recording a windowed signal from the energy dispersed fluorescence emission while varying incident photon energy), thereby yielding highly resolved X-ray absorption fine structure (XAFS) spectra. Such spectra often display resonant features not observed in conventional XAFS. The spectrometer set-up can also be used for a wide range of other experiments, for example, resonant inelastic X-ray scattering (RIXS), where bulk electron configuration information in solids, liquids and gases is obtained. Valence-selective XAFS studies, where the local structure of a selected element's valence state present in a mixture of valence states can be obtained, as well as site-selective XAFS studies, where the coordination structure of a metal bound to selected elements can be differentiated from that of all the other ligating atoms. A HRXES spectrometer has been constructed and is presently being commissioned for use at the INE-Beamline for actinide research at the synchrotron source ANKA at FZK. We present the spectrometer's compact, modular design, optimized for attaining a wide range of energies, and first test measurement results. Examples from HRXES studies of lanthanides, actinides counter parts, are also shown.

  12. Concentration of actinides in the food chain

    International Nuclear Information System (INIS)

    Bulman, R.A.

    1976-06-01

    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)

  13. Alkyl, hydride, and related bis(trimethylsilyl)-amide derivatines of the 4f- and 5f-block metals

    International Nuclear Information System (INIS)

    Andersen, R.A.

    1979-12-01

    Physical properties (magnetic susceptibility, NMR, crystal structure, etc.) are reviewed for trivalent lanthanide/actinide derivatives, divalent lanthanide derivatives, and tetravalent actinide derivatives

  14. Lanthanide/Actinide Opacities

    Science.gov (United States)

    Hungerford, Aimee; Fontes, Christopher J.

    2018-06-01

    Gravitational wave observations benefit from accompanying electromagnetic signals in order to accurately determine the sky positions of the sources. The ejecta of neutron star mergers are expected to produce such electromagnetic transients, called macronovae (e.g. the recent and unprecedented observation of GW170817). Characteristics of the ejecta include large velocity gradients and the presence of heavy r-process elements, which pose significant challenges to the accurate calculation of radiative opacities and radiation transport. Opacities include a dense forest of bound-bound features arising from near-neutral lanthanide and actinide elements. Here we present an overview of current theoretical opacity determinations that are used by neutron star merger light curve modelers. We will touch on atomic physics and plasma modeling codes that are used to generate these opacities, as well as the limited body of laboratory experiments that may serve as points of validation for these complex atomic physics calculations.

  15. Relativistic studies in actinides

    International Nuclear Information System (INIS)

    Weinberger, P.; Gonis, A.

    1987-01-01

    In this review the theoretical background is given for a relativistic description for actinide systems. A short introduction is given of the density functional theory which forms the basis for a fully relativistic single-particle theory. A section on the Dirac Hamiltonian is followed by a brief summary on group theoretical concepts. Single site scattering is presented such that formal extensions to the case of the presence of an internal (external) magnetic field and/or anisotropic scattering are evident. Multiple scattering is discussed such that it can readily be applied also to the problem of dislocations. In connection with the problem of selfconsistency particular attention is drawn to the use of complex energies. Finally the various theoretical aspects discussed are illustrated through the results of numerical calculations. 101 refs.; 37 figs.; 5 tabs

  16. Molecular cluster theory of chemical bonding in actinide oxide

    International Nuclear Information System (INIS)

    Ellis, D.E.; Gubanov, V.A.; Rosen, A.

    1978-01-01

    The electronic structure of actinide monoxides AcO and dioxides AcO 2 , where Ac = Th, U, Np, Pu, Am, Cm and Bk has been studied by molecular cluster methods based on the first-principles one-electron local density theory. Molecular orbitals for nearest neighbor clusters AcO 10- 6 and AcO 12- 8 representative of monoxide and dioxide lattices were obtained using non-relativistic spin-restricted and spin-polarized Hartree-Fock-Slater models for the entire series. Fully relativistic Dirac-Slater calculations were performed for ThO, UO and NpO in order to explore magnitude of spin-orbit splittings and level shifts in valence structure. Self-consistent iterations were carried out for NpO, in which the NpO 6 cluster was embedded in the molecular field of the solid. Finally, a ''moment polarized'' model which combines both spin-polarization and relativistic effects in a consistent fashion was applied to the NpO system. Covalent mixing of oxygen 2p and Ac 5f orbitals was found to increase rapidly across the actinide series; metal s,p,d covalency was found to be nearly constant. Mulliken atomic population analysis of cluster eigenvectors shows that free-ion crystal field models are unreliable, except for the light actinides. X-ray photoelectron line shapes have been calculated and are found to compare rather well with experimental data on the dioxides

  17. Projected benefits of actinide partitioning

    International Nuclear Information System (INIS)

    Braun, C.; Goldstein, M.

    1976-05-01

    Possible benefits that could accrue from actinide separation and transmutations are presented. The time frame for implementing these processes is discussed and the expected benefits are qualitatively described. These benefits are provisionally quantified in a sample computation

  18. Environmental research on actinide elements

    International Nuclear Information System (INIS)

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

    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

  19. CHARACTERIZATION AND ACTUAL WASTE TEST WITH TANK 5F SAMPLES

    International Nuclear Information System (INIS)

    Fletcher, D.

    2007-01-01

    The initial phase of bulk waste removal operations was recently completed in Tank 5F. Video inspection of the tank indicates several mounds of sludge still remain in the tank. Additionally, a mound of white solids was observed under Riser 5. In support of chemical cleaning and heel removal programs, samples of the sludge and the mound of white solids were obtained from the tank for characterization and testing. A core sample of the sludge and Super Snapper sample of the white solids were characterized. A supernate dip sample from Tank 7F was also characterized. A portion of the sludge was used in two tank cleaning tests using oxalic acid at 50 C and 75 C. The filtered oxalic acid from the tank cleaning tests was subsequently neutralized by addition to a simulated Tank 7F supernate. Solids and liquid samples from the tank cleaning test and neutralization test were characterized. A separate report documents the results of the gas generation from the tank cleaning test using oxalic acid and Tank 5F sludge. The characterization results for the Tank 5F sludge sample (FTF-05-06-55) appear quite good with respect to the tight precision of the sample replicates, good results for the glass standards, and minimal contamination found in the blanks and glass standards. The aqua regia and sodium peroxide fusion data also show good agreement between the two dissolution methods. Iron dominates the sludge composition with other major contributors being uranium, manganese, nickel, sodium, aluminum, and silicon. The low sodium value for the sludge reflects the absence of supernate present in the sample due to the core sampler employed for obtaining the sample. The XRD and CSEM results for the Super Snapper salt sample (i.e., white solids) from Tank 5F (FTF-05-07-1) indicate the material contains hydrated sodium carbonate and bicarbonate salts along with some aluminum hydroxide. These compounds likely precipitated from the supernate in the tank. A solubility test showed the material

  20. Theoretical modelling of actinide spectra in solution

    International Nuclear Information System (INIS)

    Danilo, Cecile

    2009-01-01

    The framework of this PhD is the interpretation of Nuclear Magnetic Relaxation Dispersion experiments performed on solvated U"4"+, NpO_2"+ and PuO_2"2"+, which all have a f"2 configuration. Unexpectedly the two actinyl ions have a much higher relaxivity than U"4"+,. One possible explanation is that the electronic relaxation rate is faster for Uranium(IV) than for the actinyl ions. We address this problem by exploring the electronic spectrum of the three compounds in gas phase and in solution with a two-step SOCI (Spin-Orbit Configuration-Interaction) method. The influence of electron correlation (treated in the first step) and spin-orbit relaxation effects (considered in the second step) has been discussed thoroughly. Solvent effects have been investigated as well. Another issue that has been questioned is the accuracy of Density Functional Theory for the study of actinide species. This matter has been discussed by comparing its performance to wave-function based correlated methods. The chemical problem chosen was the water exchange in [UO_2"2"+ (H_2O)_5]. We looked at the associative and at the dissociative mechanisms using a model with one additional water in the second hydration sphere. The last part of the thesis dealt with the spectroscopy of coordinated Uranyl(V). Absorption spectrum of Uranyl(V) with various ligands has been recorded. The first sharp absorption bands in the Near-Infrared region were assigned to the Uranium centered 5f-5f transitions, but uncertainties remained for the assignment of transitions observed in the Visible region. We computed the spectra of naked UO_2"+ and [UO_2(CO_3)_3]"5"- to elucidate the spectral changes induced by the carbonate ligands. (author) [fr

  1. Properties of minor actinide nitrides

    International Nuclear Information System (INIS)

    Takano, Masahide; Itoh, Akinori; Akabori, Mitsuo; Arai, Yasuo; Minato, Kazuo

    2004-01-01

    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)

  2. About the correlation between electronic configurations of actinide ions and the properties of their compounds

    International Nuclear Information System (INIS)

    Ionova, G.V.; Spytsyn, V.I.

    1979-01-01

    The main purpose of this paper is to show the importance of the reconstruction energies on the actinide properties both in solid state and solutions. As a consequence of the specific dualism localization-delocalization of the 5f and 6d electrons, charge waves can occur in crystal compounds at low temperature. In an extended two-band Hubbard model which takes into account the intra- and inter-site Coulomb interactions as well as the kinetic energy, the criteria for the occurrence of the charge and orbital waves are obtained. Orbital ordering can be accompanied by spin density wave formation. Partial attention is given to the occurrence of supraconductivity, it is proposed that electron pair formation in a mixed valence state is one of the important mechanisms of supraconductivity state formation. The influence of the excitation energy on the stability and geometry is analysed. Estimates of the Cm(IV-V), Cm(V-VI) and Cm(VI-VII) oxidation potentials are given. It is shown that distortion from the linear to the bent structure is possible for AnO 2 + cations

  3. Hyperfine Fields on Actinide Impurities in Ferromagnetic Fe and Ni Hosts

    International Nuclear Information System (INIS)

    Oliveira, A.L. de; Oliveira, N.A. de; Troper, A.

    2003-01-01

    We discuss the local magnetic moments and magnetic hyperfine fields on actinide impurities diluted in Fe and Ni hosts. One adopts a Anderson- Moriya model in which a localized 5f level is hybridized with a spin polarized and charge perturbed d-conduction band. Our self-consistent numerical calculations for the hyperfine fields on the impurity sites are in good agreement with the available experimental data. (author)

  4. Probing the chemistry, electronic structure and redox energetics in pentavalent organometallic actinide complexes

    Energy Technology Data Exchange (ETDEWEB)

    Graves, Christopher R [Los Alamos National Laboratory; Vaughn, Anthony E [Los Alamos National Laboratory; Morris, David E [Los Alamos National Laboratory; Kiplinger, Jaqueline L [Los Alamos National Laboratory

    2008-01-01

    Complexes of the early actinides (Th-Pu) have gained considerable prominence in organometallic chemistry as they have been shown to undergo chemistries not observed with their transition- or lanthanide metal counterparts. Further, while bonding in f-element complexes has historically been considered to be ionic, the issue of covalence remains a subject of debate in the area of actinide science, and studies aimed at elucidating key bonding interactions with 5f-orbitals continue to garner attention. Towards this end, our interests have focused on the role that metal oxidation state plays in the structure, reactivity and spectral properties of organouranium complexes. We report our progress in the synthesis of substituted U{sup V}-imido complexes using various routes: (1) Direct oxidation of U{sup IV}-imido complexes with copper(I) salts; (2) Salt metathesis with U{sup V}-imido halides; (3) Protonolysis and insertion of an U{sup V}-imido alkyl or aryl complex with H-N{double_bond}CPh{sub 2} or N{triple_bond}C-Ph, respectively, to form a U{sup V}-imido ketimide complex. Further, we report and compare the crystallographic, electrochemical, spectroscopic and magnetic characterization of the pentavalent uranium (C{sub 5}Me{sub 5}){sub 2}U({double_bond}N-Ar)(Y) series (Y = OTf, SPh, C{triple_bond}C-Ph, NPh{sub 2}, OPh, N{double_bond}CPh{sub 2}) to further interrogate the molecular, electronic, and magnetic structures of this new class of uranium complexes.

  5. Advanced Aqueous Separation Systems for Actinide Partitioning

    Energy Technology Data Exchange (ETDEWEB)

    Nash, Ken [Washington State Univ., Pullman, WA (United States); Martin, Leigh [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lumetta, Gregg [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-04-02

    One of the most challenging aspects of advanced processing of used nuclear fuel is the separation of transplutonium actinides from fission product lanthanides. This separation is essential if actinide transmutation options are to be pursued in advanced fuel cycles, as lanthanides compete with actinides for neutrons in both thermal and fast reactors, thus limiting efficiency. The separation is difficult because the chemistry of Am3+ and Cm3+ is nearly identical to that of the trivalent lanthanides (Ln3+). The prior literature teaches that two approaches offer the greatest probability of devising a successful group separation process based on aqueous processes: 1) the application of complexing agents containing ligand donor atoms that are softer than oxygen (N, S, Cl-) or 2) changing the oxidation state of Am to the IV, V, or VI state to increase the essential differences between Am and lanthanide chemistry (an approach utilized in the PUREX process to selectively remove Pu4+ and UO22+ from fission products). The latter approach offers the additional benefit of enabling a separation of Am from Cm, as Cm(III) is resistant to oxidation and so can easily be made to follow the lanthanides. The fundamental limitations of these approaches are that 1) the soft(er) donor atoms that interact more strongly with actinide cations than lanthanides form substantially weaker bonds than oxygen atoms, thus necessitating modification of extraction conditions for adequate phase transfer efficiency, 2) soft donor reagents have been seen to suffer slow phase transfer kinetics and hydro-/radiolytic stability limitations and 3) the upper oxidation states of Am are all moderately strong oxidants, hence of only transient stability in media representative of conventional aqueous separations systems. There are examples in the literature of both approaches having been described. However, it is not clear at present that any extant process is sufficiently robust for application at the scale

  6. Thermodynamic properties of actinide aqueous species relevant to geochemical problems

    International Nuclear Information System (INIS)

    Fuger, J.

    1992-01-01

    The status of our knowledge of the basic thermodynamic properties of the aqueous complexes of the actinides in their different valency states with two environmentally important ligands, namely hydroxide and carbonate is overviewed. Even in the case of uranium which has been the most studied, gaps are found among the relative wealth of trustworthy formation constants, especially for the less stable valence states. The need for substantial improvement of our knowledge in the case of the other actinides, especially transuranium elements, is outlined. The relative scarcity of enthalpy of formation data is also stressed. (orig.)

  7. Actinide colloid generation in groundwater. Part 2

    International Nuclear Information System (INIS)

    Kim, J.I.

    1991-01-01

    The progress made in the investigation of actinide colloid generation in groundwater is summarized and discussed with particular examples relevant to an understanding of the migration behaviour of actinides in natural aquifer systems. The first part deals with the characterization of colloids: groundwater colloids, actinide real-colloids and actinide pseudocolloids. The second part concentrates on the generation processes and migration behaviour of actinide pseudo colloids, which are discussed with some notable experimental examples. Importance is stressed more on the chemical aspects of the actinide colloid generation in groundwater. This work is a contribution to the CEC Mirage II project, in particular the complexation and colloids research area

  8. Actinide/crown ether chemistry

    International Nuclear Information System (INIS)

    Benning, M.M.

    1988-01-01

    A structural survey of actinide/crown ether compounds was conducted in order to investigate the solid state chemistry of these complexes. Several parameters - the metal size, crown type, counterion, solvent systems and reaction and crystallization conditions - were varied to correlate their importance in complexation. Under atmospheric conditions, two types of complexes were isolated, those containing only hydrogen-bonded crown interactions and instances where the crown interacts directly with the metal center. In both cases, water seems to play a very important role. When coordinated to the metal, water molecules exhibit the necessary donor properties required for the formation of hydrogen-bonded contacts. The water molecules also provide fierce competition with the crown ethers for metal-binding sites and in most cases prohibit the formation of complexes in which direct metal-ligand association exists. The results of this study indicate that direct interaction between the metal atoms and the crown ethers, in the presence of water, can only occur with polyether conformations which limit the steric replusions within the metal coordination sphere

  9. Actinides and heavy fermions

    International Nuclear Information System (INIS)

    Smith, J.L.; Fisk, Z.; Ott, H.R.

    1987-01-01

    The actinide series of elements begins with f-shell electrons forming energy bands, contributing to the bonding, and possessing no magnetic moments. At americium the series switches over to localized f electrons with magnetic moments. In metallic compounds this crossover of behavior can be modified and studied. In this continuum of behavior a few compounds on the very edge of localized f-electron behavior exhibit enormous electronic heat capacities at low temperatures. This is associated with an enhanced thermal mass of the conduction electrons, which is well over a hundred times the free electron mass, and is what led to the label heavy fermion for such compounds. A few of these become superconducting at even lower temperatures. The excitement in this field comes from attempting to understand how this heaviness arises and from the likelihood that the superconductivity is different from that of previously known superconductors. The effects of thorium impurities in UBe 13 were studied as a representative system for studying the nature of the superconductivity

  10. Selective extraction of actinides from high level liquid wastes. Study of the possibilities offered by the Redox properties of actinides

    International Nuclear Information System (INIS)

    Adnet, J.M.

    1991-07-01

    Partitioning of high level liquid wastes coming from nuclear fuel reprocessing by the PUREX process, consists in the elimination of minor actinides (Np, Am, and traces of Pu and U). Among the possible processes, the selective extraction of actinides with oxidation states higher than three is studied. First part of this work deals with a preliminary step; the elimination of the ruthenium from fission products solutions using the electrovolatilization of the RuO4 compound. The second part of this work concerns the complexation and oxidation reactions of the elements U, Np, Pu and Am in presence of a compound belonging to the insaturated polyanions family: the potassium phosphotungstate. For actinide ions with oxidation state (IV) complexed with phosphotungstate anion the extraction mechanism by dioctylamine was studied and the use of a chromatographic extraction technic permitted successful separations between tetravalents actinides and trivalents actinides. Finally, in accordance with the obtained results, the basis of a separation scheme for the management of fission products solutions is proposed

  11. Actinide burning and waste disposal

    Energy Technology Data Exchange (ETDEWEB)

    Pigford, T H [University of California, Berkeley, CA (United States)

    1990-07-01

    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

  12. Actinide burning and waste disposal

    International Nuclear Information System (INIS)

    Pigford, T.H.

    1990-01-01

    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

  13. Thermodynamic analysis of light-actinide elements

    International Nuclear Information System (INIS)

    Brosh, Eli; Makov, Guy; Shneck, Roni Z.

    2005-01-01

    The thermophysical properties of the alpha phases of the light actinide elements Th, U, Np and Pu were analysed. For each of the analysed elements, the Gibbs free-energy was modelled by an explicit function of temperature T and pressure P over the whole relevant T-P range, in a manner compatible with the CALPHAD (Calculation of Alloy Phase Diagrams) method. Several adjustable model-parameters were fitted to available experimental results. The model is based on a new semi-empirical equation of state, which interpolates with Thomas-Fermi type models for the volume and with the Dulong-Petit value for the heat capacity, at extreme pressures

  14. Thermal-hydraulics of actinide burner reactors

    International Nuclear Information System (INIS)

    Takizuka, Takakazu; Mukaiyama, Takehiko; Takano, Hideki; Ogawa, Toru; Osakabe, Masahiro.

    1989-07-01

    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)

  15. Schedules of Controlled Substances: Temporary Placement of Six Synthetic Cannabinoids (5F-ADB, 5F-AMB, 5F-APINACA, ADB-FUBINACA, MDMB-CHMICA and MDMB-FUBINACA) into Schedule I. Temporary Scheduling Order.

    Science.gov (United States)

    2017-04-10

    The Administrator of the Drug Enforcement Administration is issuing this temporary scheduling order to schedule six synthetic cannabinoids: methyl 2-(1-(5-fluoropentyl)-1H-indazole-3-carboxamido)-3,3-dimethylbutanoate [5F-ADB; 5F-MDMB-PINACA]; methyl 2-(1-(5-fluoropentyl)-1H-indazole-3-carboxamido)-3-methylbutanoate [5F-AMB]; N-(adamantan-1-yl)-1-(5-fluoropentyl)-1H-indazole-3-carboxamide [5F-APINACA, 5F-AKB48]; N-(1-amino-3,3-dimethyl-1-oxobutan-2-yl)-1-(4-fluorobenzyl)-1H-indazole-3-carboxamide [ADB-FUBINACA]; methyl 2-(1-(cyclohexylmethyl)-1H-indole-3-carboxamido)-3,3-dimethylbutanoate [MDMB-CHMICA, MMB-CHMINACA] and methyl 2-(1-(4-fluorobenzyl)-1H-indazole-3-carboxamido)-3,3-dimethylbutanoate [MDMB-FUBINACA], and their optical, positional, and geometric isomers, salts, and salts of isomers into schedule I pursuant to the temporary scheduling provisions of the Controlled Substances Act. This action is based on a finding by the Administrator that the placement of these synthetic cannabinoids into schedule I of the Controlled Substances Act is necessary to avoid an imminent hazard to the public safety. As a result of this order, the regulatory controls and administrative, civil, and criminal sanctions applicable to schedule I controlled substances will be imposed on persons who handle (manufacture, distribute, reverse distribute, import, export, engage in research, conduct instructional activities or chemical analysis, or possess), or propose to handle, 5F-ADB, 5F-AMB, 5F-APINACA, ADB-FUBINACA, MDMB-CHMICA or MDMB-FUBINACA.

  16. Fusion barrier characteristics of actinides

    Science.gov (United States)

    Manjunatha, H. C.; Sridhar, K. N.

    2018-03-01

    We have studied fusion barrier characteristics of actinide compound nuclei with atomic number range 89 ≤ Z ≤ 103 for all projectile target combinations. After the calculation of fusion barrier heights and positions, we have searched for their parameterization. We have achieved the empirical formula for fusion barrier heights (VB), positions (RB), curvature of the inverted parabola (ħω) of actinide compound nuclei with atomic number range 89 ≤ Z ≤ 103 for all projectile target combinations (6 projectile target combinations. The values produced by the present formula are also compared with experiments. The present pocket formula produces fusion barrier characteristics of actinides with the simple inputs of mass number (A) and atomic number (Z) of projectile-targets.

  17. ALMR potential for actinide consumption

    International Nuclear Information System (INIS)

    Cockey, C.L.; Thompson, M.L.

    1992-01-01

    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)

  18. Thin layers in actinide research

    International Nuclear Information System (INIS)

    Gouder, T.

    1998-01-01

    Surface science research at the ITU is focused on the synthesis and surface spectroscopy studies of thin films of actinides and actinide compounds. The surface spectroscopies used are X-ray and ultra violet photoelectron spectroscopy (XPS and UPS, respectively), and Auger electron spectroscopy (AES). Thin films of actinide elements and compounds are prepared by sputter deposition from elemental targets. Alloy films are deposited from corresponding alloy targets and could be used, in principle, as replicates of these targets. However, there are deviations between alloy film and target composition, which depend on the deposition conditions, such as pressure and target voltage. Mastering of these effects may allow us to study stoichiometric film replicates instead of thick bulk compounds. As an example, we discuss the composition of U-Ni films prepared from a UNi 5 target. (orig.)

  19. Nuclear waste forms for actinides

    Science.gov (United States)

    Ewing, Rodney C.

    1999-01-01

    The disposition of actinides, most recently 239Pu from dismantled nuclear weapons, requires effective containment of waste generated by the nuclear fuel cycle. Because actinides (e.g., 239Pu and 237Np) are long-lived, they have a major impact on risk assessments of geologic repositories. Thus, demonstrable, long-term chemical and mechanical durability are essential properties of waste forms for the immobilization of actinides. Mineralogic and geologic studies provide excellent candidate phases for immobilization and a unique database that cannot be duplicated by a purely materials science approach. The “mineralogic approach” is illustrated by a discussion of zircon as a phase for the immobilization of excess weapons plutonium. PMID:10097054

  20. Actinides integral measurements on FCA assemblies

    International Nuclear Information System (INIS)

    Mukaiyama, Takehiko; Okajima, Shigeaki

    1984-01-01

    Actinide integral measurements were performed on eight assemblies of FCA where neutron energy spectra were shifted systematically from soft to hard in order to evaluate and modify the nuclear cross section data of major actinides. Experimental values on actinide fission rates and sample reactivity worths are compared with the calculated values using JENDL-2 and ENDF/B-V (or IV) data sets. (author)

  1. Complexes of actinides with naturally occuring organic substances - Literature survey

    International Nuclear Information System (INIS)

    Olofsson, U.; Allard, B.

    1983-02-01

    Properties of naturally occurring humic and fulvic acids and their formation of actinide complexes are reviewed. Actinides in all the oxdation states III, IV, V and VI would form complexes with many humic and fulvic acids, comparable in strength to the hydroxide and carbonate complexes. Preliminary experiments have shown, that the presence of predominantly humic acid complexes would significantly reduce the sorption of americium on geologic media. This does not, however, necessarily lead to a potentially enhanced mobility under environmental conditions, since humic and fulvic acids carrying trace metals also would be strongly bound to e.g. clayish material. (author)

  2. The US/UK Actinides Experiment at the Dounreay PFR

    International Nuclear Information System (INIS)

    Raman, S.; Walker, R.L.; Dickens, J.K.; Murphy, B.D.

    1997-01-01

    The United States and the United Kingdom have been engaged in a joint research program in which samples of higher actinides were irradiated in the 600-MW Dounreay Prototype Fast Reactor in Scotland. Analytical results using mass spectrometry and radiometry for actinides and fission products are now available for the samples in Fuel Pins 1 and 2, which were irradiated for 63 full-power days, and for the samples in Fuel Pin 4, which were irradiated for 492 full-power days. Results from these three fuel pins are providing estimates of integral cross sections and fission yields

  3. Experimental studies of narrow band effects in the actinides

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, M.B.

    1976-01-01

    In many actinide metallic systems the f-electrons exhibit band behavior. This is a consequence of direct f-f wave function overlap or hybridization of f-electrons with s-, p-, and d-electrons. The f-bands can be responsible for large electronic densities of states at the Fermi level which may lead to band magnetism of various types. Although the concept of valence instabilities must be approached cautiously especially in the light actinides, it would not be surprising to observe them in the future, especially in Am compounds.

  4. Experimental studies of narrow band effects in the actinides

    International Nuclear Information System (INIS)

    Brodsky, M.B.

    1976-01-01

    In many actinide metallic systems the f-electrons exhibit band behavior. This is a consequence of direct f-f wave function overlap or hybridization of f-electrons with s-, p-, and d-electrons. The f-bands can be responsible for large electronic densities of states at the Fermi level which may lead to band magnetism of various types. Although the concept of valence instabilities must be approached cautiously especially in the light actinides, it would not be surprising to observe them in the future, especially in Am compounds

  5. Preparation of higher-actinide burnup and cross section samples

    International Nuclear Information System (INIS)

    Adair, H.L.; Kobisk, E.H.; Quinby, T.C.; Thomas, D.K.; Dailey, J.M.

    1981-01-01

    A joint research program involving the United States and the United Kingdom was instigated about four years ago for the purpose of studying burnup of higher actinides using in-core irradiation in the fast reactor at Dounreay, Scotland. Simultaneously, determination of cross sections of a wide variety of higher actinide isotopes was proposed. Coincidental neutron flux and energy spectral measurements were to be made using vanadium encapsulated dosimetry materials in the immediate region of the burnup and cross section samples. The higher actinide samples chosen for the burnup study were 241 Am and 244 Cm in the forms of Am 2 O 3 , Cm 2 O 3 , and Am 6 Cm(RE) 7 O 21 , where (RE) represents a mixture of lanthanide sesquioxides. It is the purpose of this paper to describe technology development and its application in the preparation of the fuel specimens and the cross section specimens that are being used in this cooperative program

  6. Preliminary considerations concerning actinide solubilities

    International Nuclear Information System (INIS)

    Newton, T.W.; Bayhurst, B.P.; Daniels, W.R.; Erdal, B.R.; Ogard, A.E.

    1980-01-01

    Work at the Los Alamos Scientific Laboratory on the fundamental solution chemistry of the actinides has thus far been confined to preliminary considerations of the problems involved in developing an understanding of the precipitation and dissolution behavior of actinide compounds under environmental conditions. Attempts have been made to calculate solubility as a function of Eh and pH using the appropriate thermodynamic data; results have been presented in terms of contour maps showing lines of constant solubility as a function of Eh and pH. Possible methods of control of the redox potential of rock-groundwater systems by the use of Eh buffers (redox couples) is presented

  7. Safety Analysis Of Actinide Recycled Fast Power Reactor

    International Nuclear Information System (INIS)

    Taufik, Mohammad

    2001-01-01

    Simulation for safety analysis of actinide recycled fast power reactor has been performed. The objective is to know reactor response about ULOF and ULOF and UTOP simultaneous accident. From parameter result such reactivity feedback, power, temperature, and cooled flow rate can conclusion that reactor have inherent safety system, which can back to new Equilibrium State

  8. Electronic structure and ionicity of actinide oxides from first principles

    DEFF Research Database (Denmark)

    Petit, Leon; Svane, Axel; Szotek, Z.

    2010-01-01

    The ground-state electronic structures of the actinide oxides AO, A2O3, and AO2 (A=U, Np, Pu, Am, Cm, Bk, and Cf) are determined from first-principles calculations, using the self-interaction corrected local spin-density approximation. Emphasis is put on the degree of f-electron localization, whi...

  9. Quantum Chemical Calculations and Experimental Investigations of Molecular Actinide Oxides

    NARCIS (Netherlands)

    Kovács, Attila; Konings, Rudy J. M.; Gibson, John K.; Infante, Ivan; Gagliardi, Laura

    2015-01-01

    The available experimental and theoretical information on gaseous actinide oxides covering both the neutral and the ionic species are reviewed. The ground-state electronic structures of the oxides of An = Th-Cm have been obtained by the well-tested SOCASPT2 method, and therefore they are very likely

  10. Safe actinide disposition in molten salt reactors

    International Nuclear Information System (INIS)

    Gat, U.

    1997-01-01

    Safe molten salt reactors (MSR) can readily accommodate the burning of all fissile actinides. Only minor compromises associated with plutonium are required. The MSRs can dispose safely of actinides and long lived isotopes to result in safer and simpler waste. Disposing of actinides in MSRs does increase the source term of a safety optimized MSR. It is concluded that the burning and transmutation of actinides in MSRs can be done in a safe manner. Development is needed for the processing to handle and separate the actinides. Calculations are needed to establish the neutron economy and the fuel management. 9 refs

  11. Burning actinides in very hard spectrum reactors

    International Nuclear Information System (INIS)

    Robinson, A.H.; Shirley, G.W.; Prichard, A.W.; Trapp, T.J.

    1978-01-01

    The major unresolved problem in the nuclear industry is the ultimate disposition of the waste products of light water reactors. The study demonstrates the feasibility of designing a very hard spectrum actinide burner reactor (ABR). A 1100 MW/sub t/ ABR design fueled entirely with actinides reprocessed from light water reactor (LWR) wastes is proposed as both an ultimate disposal mechanism for actinides and a means of concurrently producing usable power. Actinides from discharged ABR fuel are recycled to the ABR while fission products are routed to a permanent repository. As an integral part of a large energy park, each such ABR would dispose of the waste actinides from 2 LWRs

  12. Sol-gel chemistry applied to the synthesis of polymetallic oxides including actinides reactivity and structure from solution to solid state

    International Nuclear Information System (INIS)

    Lemonnier, St.

    2006-02-01

    Minor actinides transmutation is studied at present in order to reduce the radiotoxicity of nuclear waste and the assessment of its technical feasibility requires specific designed materials. When considering americium, yttria stabilized zirconia (Am III YII Zriv)Or x is among the ceramic phases that one which presents the required physico-chemical properties. An innovative synthesis of this mixed oxide by sol-gel process is reported in this manuscript. The main aim of this work is to adjust the reactivity of the different metallic cations in aqueous media using complexing agent, in order to initiate a favourable interaction for a homogeneous elements repartition in the forming solid phase. The originality of the settled synthesis lies on an in-situ formation of a stable and monodisperse nano-particles dispersion in the presence of acetylacetone. The main reaction mechanisms have been identified: the sol stabilisation results from an original interaction between the three compounds (Zrly, trivalent cations and acetylacetone). The sol corresponds to a structured system at the nanometer scale for which zirconium and trivalent cations are homogeneously dispersed, preliminary to the sol-gel transition. Furthermore, preliminary studies were carried out with a view to developing materials. They have demonstrated that numerous innovative and potential applications can be developed by taking advantage of the direct and controlled formation of the sol and by adapting the sol-gel transition. The most illustrating result is the preparation of a sintered pellet with the composition Am0,13Zro,73Yo,0901,89 using this approach. (author)

  13. Research on the chemical speciation of actinides

    International Nuclear Information System (INIS)

    Jung, Euo Chang; Park, K. K.; Cho, H. R.

    2010-04-01

    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

  14. ENDF/B-V actinides

    International Nuclear Information System (INIS)

    Kocherov, N.; Lemmel, H.D.

    1981-01-01

    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)

  15. Environmental research on actinide elements

    Energy Technology Data Exchange (ETDEWEB)

    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)

  16. Photochemical reactions of actinide ions

    International Nuclear Information System (INIS)

    Tomiyasu, Hiroshi

    1995-01-01

    This paper reviews the results of photochemical studies of actinide ions, which have been performed in our research group for past several years as follows: I) behavior of the excited uranyl(VI) ion; II) photo-reductions of the uranyl ion with organic and inorganic compounds; III) photo-oxidations of uranium(IV) and plutonium(III) in nitric acid solutions. (author)

  17. Angular overlap model in actinides

    International Nuclear Information System (INIS)

    Gajek, Z.; Mulak, J.

    1991-01-01

    Quantitative foundations of the Angular Overlap Model in actinides based on ab initio calculations of the crystal field effect in the uranium (III) (IV) and (V) ions in various crystals are presented. The calculations justify some common simplifications of the model and fix up the relations between the AOM parameters. Traps and limitations of the AOM phenomenology are discussed

  18. Angular overlap model in actinides

    Energy Technology Data Exchange (ETDEWEB)

    Gajek, Z.; Mulak, J. (Polska Akademia Nauk, Wroclaw (PL). Inst. Niskich Temperatur i Badan Strukturalnych)

    1991-01-01

    Quantitative foundations of the Angular Overlap Model in actinides based on ab initio calculations of the crystal field effect in the uranium (III) (IV) and (V) ions in various crystals are presented. The calculations justify some common simplifications of the model and fix up the relations between the AOM parameters. Traps and limitations of the AOM phenomenology are discussed.

  19. Observations of multiple order parameters in 5f electron systems

    International Nuclear Information System (INIS)

    Blackburn, E.

    2005-12-01

    In this thesis, multiple order parameters originating in the same electronic system are studied. The multi-k magnetic structures, where more than one propagation wavevector, k, is observed in the same volume, are considered as prototypical models. The effect of this structure on the elastic and inelastic response is studied. In cubic 3-k uranium rock-salts, unexpected elastic diffraction events were observed at positions in reciprocal space where the structure factor should have been zero. These diffraction peaks are identified with correlations between the (orthogonal) magnetic order parameters. The 3-k structure also affects the observed dynamics; the spin-wave fluctuations in uranium dioxide as observed by inelastic neutron polarization analysis can only be explained on the basis of a 3-k structure. In the antiferromagnetic superconductor UPd 2 Al 3 the magnetic order and the super-conducting state coexist, and are apparently generated by the same heavy fermions. The effect of an external magnetic field on both the normal and superconducting states is examined. In the normal state, the compound displays Fermi-liquid-like behaviour. The inelastic neutron response is strongly renormalized on entering the superconducting state, and high-precision measurements of the low-energy transfer part of this response confirm that the superconducting energy gap has the same symmetry as the antiferromagnetic lattice. (author)

  20. Actinides and environmental interfaces: striving for molecular-level understanding

    International Nuclear Information System (INIS)

    Heino Nitsche

    2005-01-01

    Actinides can undergo a variety of complex chemical reactions in the environment. In addition to the formation of solid precipitates, colloids and dissolved solution species common to aqueous systems, actinide ions can interact with the surrounding geo and biomedia to change oxidation states or sorb on surfaces and colloids. The rate of migration is determined by aqueous solubility, and interactions with solid surfaces such as minerals, soils, natural organic matter, and soil microorganisms Sorption of aqueous actinide species on biological and geological matrices can be quantitatively described by a surface complexation or site-binding model. The disadvantage of this model is the difficulty in the experimental determination of the model parameters and surface reaction constants. Usually, a set of surface reactions and species are proposed based on knowledge of the solution speciation of the solute, and the reaction constants are usually derived by fitting computer-calculated absorption curves to experimental data. Because this process typically involves a large number of potentially adjustable parameters, it is likely to lead to non-unique parameter fitting and does not always result in a consistent set of parameters for the same systems. A fundamental molecular-level understanding of sorption processes of actinides on environmental surfaces is required to better understand and predict their transport behavior in nature. Several different surface spectroscopic techniques have been applied to the characterization of the adsorbed species and surface reactions and a direct determination of the sorbed species and surface reactions has become possible. The non-linear optical techniques of second harmonic and sum frequency generation (SHG and SFG) are ideally suited to study surfaces and interfaces of mineral oxides, biosurfactants and biopolymers, organic adlayers adsorbed on solid/mineral surfaces and soil organic matter, including humic and fulvic acids. Resonant

  1. Valence instabilities as a source of actinide system inconsistencies

    International Nuclear Information System (INIS)

    Sandenaw, T.A.

    1979-01-01

    Light actinide elements alone, and in some of their alloys, may exist as a static or dynamic mixture of two configurations. Such a state can explain both a resistivity maximum and lack of magnetic order observed in so many actinide materials, and still be compatible with the existence of f-electrons in narrow bands. Impurity elements may stabilize slightly different intermediate valence states in U, Np, and Pu, thus contributing to inconsistencies in published results. The physical property behavior of mixed-valence, rare-earth compounds is very much like that observed in development of antiphase (martensitic) structures. Martensitic transformations in U, Np, and Pu, from high-temperature b. c. c. to alpha phase, may be a way of ordering an alloy-like metal of mixed or intermediate valence. The relative stability of each phase structure may depend upon its electron-valence ratio. A Hubbard model for electron correlations in a narrow energy band has been invoked in most recent theories for explaining light actinide behavior. Such a model may also be applicable to crystal symmetry changes in martensitic transformations in actinides

  2. Signatures of Non-integer 5f Occupancy in Pu Systems: Magnetic Properties and Photoelectron Spectroscopy Studies

    International Nuclear Information System (INIS)

    Havela, Ladislav; Shick, Alexander; Gouder, Thomas; Wastin, Franck; Rebizant, Jean

    2008-01-01

    Very diverse Pu compounds exhibit strikingly universal features in their valence-band photoemission (PES) spectra. The conjecture that such features represent the 5f 5 final state multiplet has been corroborated by LDA+Hubbard calculations, meaning that the ground state has a mixed 5f 5 -5f 6 character. Later on, more elaborated DMFT techniques (one crossing approximation, QMC) led to similar conclusions, providing quantitative explanation of such intermediate-valent situation in more details. Analogies in PES spectra of δ-Pu and other Pu systems suggest that the situation envisaged for δ-Pu is relevant for a large group of Pu compounds. Here we show that the around mean field LDA+U in conjunction with the Hubbard I approximation, which describes well the non-magnetic ground state for δ-Pu, captures in reality properties of a large group of Pu (as well as e.g. Am) compounds, reproducing correctly the onset of magnetism and size of magnetic moments. (authors)

  3. Coprecipitation of aluminium with hydroxides of tetra-, penta- and hexavalent actinides

    International Nuclear Information System (INIS)

    Yusov, A.B.; Budantseva, N.A.; Anan'ev, A.V.; Fedoseev, A.M.

    2000-01-01

    By the methods of IR spectroscopy and powder x-ray diffractometry precipitates formed in alkaline medium by actinide (4, 5, 6) in the presence of aluminium are studied. It is shown that in studied conditions formation of actinide aluminates not occurs. In the same time in the process of precipitation interaction of aluminium hydroxocomplexes with U(6) and Th(4) ions probably takes place. Hypothesis is expressed that possibility of aluminium hydroxocomplexes interaction with actinides in different oxidation state is depended on peculiarities of hydrolytic behaviour of the lasts [ru

  4. Actinide Sciences at ITN - Basic Studies in Chemistry with Potential Interest for Partitioning, Fuel Fabrication and More

    International Nuclear Information System (INIS)

    Almeida, M.; Dias, M.; Goncalves, A.P.; Henriques, M.S.; Lopes, E.B.; Pereira, L.C.J.; Santos, I.C.; Verbovytskyy, Y.; Waerenborgh, J.C.; Branco, J.B.; Carretas, J.M.; Cruz, A.; Ferreira, A.C.; Gasche, T.A.; Leal, J.P.; Lopes, G.; Lourenco, C.; Marcalo, J.; Maria, L.; Monteiro, B.; Mora, E.; Pereira, C.C.L.; Paiva, I.

    2010-01-01

    The current activities in the area of actinide chemistry at ITN, comprising basic research studies in inorganic and organometallic chemistry, catalysis, gas-phase ion chemistry, thermochemistry, and solid state chemistry, are briefly described. Actinide (and lanthanide) chemistry studies at ITN will be pursued connecting basic research with potential applications in nuclear and non-nuclear areas. (authors)

  5. Actinide recovery techniques utilizing electromechanical processes

    International Nuclear Information System (INIS)

    Westphal, B.R.; Benedict, R.W.

    1994-01-01

    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 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

  6. Actinide recovery techniques utilizing electromechanical processes

    International Nuclear Information System (INIS)

    Westphal, B.R.; Benedict, R.W.

    1994-01-01

    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

  7. Analytical evaluation of actinide sensitivities

    International Nuclear Information System (INIS)

    Sola, A.

    1977-01-01

    The analytical evaluation of the sensitivities of actinides to various parameters such as cross sections, decay constants, flux and time is presented. The formulae are applied to isotopes of the Uranium, Neptunium, Plutonium and Americium series. The agreement between analytically obtained and computer evaluated sensitivities being always good, it is throught that the formulation includes all the important parameters entering in the evaluation of sensitivities. A study of the published data is made

  8. Reversible optical sensor for the analysis of actinides in solution

    International Nuclear Information System (INIS)

    Lesage, B.; Picard, S.; Serein-Spirau, F.; Lereporte, J.P.

    2007-01-01

    In this work is presented a concept of reversible optical sensor for actinides. It is composed of a p doped conducing polymer support and of an anion complexing the actinides. The chosen conducing polymer is the thiophene-2,5-di-alkoxy-benzene whose solubility and conductivity are perfectly known. The actinides selective ligand is a lacunar poly-oxo-metallate such as P 2 W 17 O 61 10- or SiW 11 O 39 8- which are strong anionic complexing agents of actinides at the oxidation state (IV) even in a very acid medium. The sensor is prepared by spin coating of the composite mixture 'polymer + ligand' on a conducing glass electrode and then tested towards its optical and electrochemical answer in presence of uranium (IV). The absorption change due to the formation of cations complexes by poly-oxo-metallate reveals the presence of uranium (IV). After the measurement, the sensor is regenerated by anodic polarization of the support and oxidation of the uranium (IV) into uranium (VI) which weakly interacts with the poly-oxo-metallate and is then released in solution. (O.M.)

  9. Review of the sorption of actinides on natural minerals

    International Nuclear Information System (INIS)

    Beall, G.W.

    1981-01-01

    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. The Dirac equation in electronic structure calculations: Accurate evaluation of DFT predictions for actinides

    International Nuclear Information System (INIS)

    Wills, John M.; Mattsson, Ann E.

    2012-01-01

    Brooks, Johansson, and Skriver, using the LMTO-ASA method and considerable insight, were able to explain many of the ground state properties of the actinides. In the many years since this work was done, electronic structure calculations of increasing sophistication have been applied to actinide elements and compounds, attempting to quantify the applicability of DFT to actinides and actinide compounds and to try to incorporate other methodologies (i.e. DMFT) into DFT calculations. Through these calculations, the limits of both available density functionals and ad hoc methodologies are starting to become clear. However, it has also become clear that approximations used to incorporate relativity are not adequate to provide rigorous tests of the underlying equations of DFT, not to mention ad hoc additions. In this talk, we describe the result of full-potential LMTO calculations for the elemental actinides, comparing results obtained with a full Dirac basis with those obtained from scalar-relativistic bases, with and without variational spin-orbit. This comparison shows that the scalar relativistic treatment of actinides does not have sufficient accuracy to provide a rigorous test of theory and that variational spin-orbit introduces uncontrolled errors in the results of electronic structure calculations on actinide elements.

  11. Research on the chemical speciation of actinides

    International Nuclear Information System (INIS)

    Jung, Euo Chang; Park, K. K.; Cho, H. R.

    2012-04-01

    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

  12. Chemistry of actinides and fission products

    International Nuclear Information System (INIS)

    Pruett, D.J.; Sherrow, S.A.; Toth, L.M.

    1988-01-01

    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

  13. Correlation consistent basis sets for actinides. II. The atoms Ac and Np-Lr.

    Science.gov (United States)

    Feng, Rulin; Peterson, Kirk A

    2017-08-28

    New correlation consistent basis sets optimized using the all-electron third-order Douglas-Kroll-Hess (DKH3) scalar relativistic Hamiltonian are reported for the actinide elements Ac and Np through Lr. These complete the series of sets reported previously for Th-U [K. A. Peterson, J. Chem. Phys. 142, 074105 (2015); M. Vasiliu et al., J. Phys. Chem. A 119, 11422 (2015)]. The new sets range in size from double- to quadruple-zeta and encompass both those optimized for valence (6s6p5f7s6d) and outer-core electron correlations (valence + 5s5p5d). The final sets have been contracted for both the DKH3 and eXact 2-component (X2C) Hamiltonians, yielding cc-pVnZ-DK3/cc-pVnZ-X2C sets for valence correlation and cc-pwCVnZ-DK3/cc-pwCVnZ-X2C sets for outer-core correlation (n = D, T, Q in each case). In order to test the effectiveness of the new basis sets, both atomic and molecular benchmark calculations have been carried out. In the first case, the first three atomic ionization potentials (IPs) of all the actinide elements Ac-Lr have been calculated using the Feller-Peterson-Dixon (FPD) composite approach, primarily with the multireference configuration interaction (MRCI) method. Excellent convergence towards the respective complete basis set (CBS) limits is achieved with the new sets, leading to good agreement with experiment, where these exist, after accurately accounting for spin-orbit effects using the 4-component Dirac-Hartree-Fock method. For a molecular test, the IP and atomization energy (AE) of PuO 2 have been calculated also using the FPD method but using a coupled cluster approach with spin-orbit coupling accounted for using the 4-component MRCI. The present calculations yield an IP 0 for PuO 2 of 159.8 kcal/mol, which is in excellent agreement with the experimental electron transfer bracketing value of 162 ± 3 kcal/mol. Likewise, the calculated 0 K AE of 305.6 kcal/mol is in very good agreement with the currently accepted experimental value of 303.1 ± 5 kcal

  14. Photoionization cross-sections of ground and excited valence levels of actinides

    Directory of Open Access Journals (Sweden)

    Yarzhemsky Victor G.

    2012-01-01

    Full Text Available The photoionization cross-sections of ground and excited atomic states of actinide atoms were calculated by the Dirac-Fock-Slater method for two excitation energies of X-ray radiation (1253.6 eV and 1486.6 eV. These data are required for calculations of intensities of X-ray photoelectron spectra of actinide compound valence bands and interpretation of experimental spectra.

  15. Assessment of Partitioning Processes for Transmutation of Actinides

    International Nuclear Information System (INIS)

    2010-04-01

    To obtain public acceptance of future nuclear fuel cycle technology, new and innovative concepts must overcome the present concerns with respect to both environmental compliance and proliferation of fissile materials. Both these concerns can be addressed through the multiple recycling of all transuranic elements (TRUs) in fast neutron reactor. This is only possible through a process known as partitioning and transmutation scheme (P and T) as this scheme is expected to reduce the long term radio-toxicity as well as the radiogenic heat production of the nuclear waste. Proliferation resistance of separated plutonium could further be enhanced by mixing with self-generated minor actinides. In addition, P and T scheme is expected to extend the nuclear fuel resources on earth about 100 times because of the recycle and reuse of fissile actinides. Several Member States are actively pursuing the research in the field of P and T and consequently several IAEA publications have addressed this topic. The present coordinated research project (CRP) focuses on the potentials in minimizing the residual TRU inventories of the discharged nuclear waste and in enhancing the proliferation resistance of the future civil nuclear fuel cycle. Partitioning approaches can be grouped into aqueous- (hydrometallurgical) and pyroprocesses. Several aqueous processes based on sequential separation of actinides from spent nuclear fuel have been developed and tested at pilot plant scale. In view of the proliferation resistance of the intermediate and final products of a P and T scheme, a group separation of all actinides together is preferable. The present CRP has gathered experts from different organisations and institutes actively involved in developing P and T scheme as mentioned in the list of contributors and also taken into consideration the studies underway in France and the UK. The scientific objectives of the CRP are: To minimize the environmental impact of actinides in the waste stream; To

  16. Th-Based Endohedral Metallofullerenes: Anomalous Metal Position and Significant Metal-Cage Covalent Interactions with the Involvement of Th 5f Orbitals.

    Science.gov (United States)

    Li, Ying; Yang, Le; Liu, Chang; Hou, Qinghua; Jin, Peng; Lu, Xing

    2018-05-29

    Endohedral metallofullerenes (EMFs) containing actinides are rather intriguing due to potential 5f-orbital participation in the metal-metal or metal-cage bonding. In this work, density functional theory calculations first characterized the structure of recently synthesized ThC 74 as Th@ D 3 h (14246)-C 74 . We found that the thorium atom adopts an unusual off-axis position inside cage due to small metal ion size and the requirement of large coordination number, which phenomenon was further extended to other Th-based EMFs. Significantly, besides the strong metal-cage electrostatic attractions, topological and orbital analysis revealed that all the investigated Th-based EMFs exhibit obvious covalent interactions between metal and cage with substantial contribution from the Th 5f orbitals. The encapsulation by fullerenes is thus proposed as a practical pathway toward the f-orbital covalency for thorium. Interestingly, the anomalous internal position of Th led to a novel three-dimensional metal trajectory at elevated temperatures in the D 3 h -C 74 cavity, as elucidated by the static computations and molecular dynamic simulations.

  17. Structural organization and spectroscopy of peptide-actinide(IV) complexes

    International Nuclear Information System (INIS)

    Dahou, S.

    2010-01-01

    The contamination of living organisms by actinide elements is at the origin of both radiological and chemical toxicity that may lead to severe dysfunction. Most of the data available on the actinide interaction with biological systems are macroscopic physiological measurements and are lacking a molecular description of the systems. Because of the intricacy of these systems, classical biochemical methods are difficult to implement. Our strategy consisted in designing simplified biomimetic peptides, and describing the corresponding intramolecular interactions with actinides. A carboxylic pentapeptide of the form DDPDD has been at the starting point of this work in order to further assess the influence of the peptide sequence on the topology of the complexes.To do so, various linear (Asp/Ala permutations, peptoids) and cyclic analogues have been synthesized. Furthermore, in order to include the hydroxamic function (with a high affinity for Fe(III)) in the peptide, both desferrioxamine and acetohydroxamic acid have been investigated. However because of difficulties in synthesis, we have not been able to test these peptides. Three actinide cations have been considered at oxidation state +IV (Th, Np, Pu) and compared to Fe(III), often considered as a biological surrogate of Pu(IV). The spatial arrangement of the peptide around the cation has been probed by spectrophotometry and X-ray Absorption Spectroscopy. The spectroscopic data and EXAFS data adjustment lead us to rationalize the topology of the complexes as a function of the peptide sequence: mix hydroxy polynuclear species for linear and cyclic peptides, mononuclear for the desferrioxamine complexes. Furthermore, significant differences have appeared between Fe(III) and actinide(IV), related to differences of reactivity in aqueous medium. (author)

  18. Oxidation-reduction properties of americium, curium, berkelium, californium, einsteinium and fermium, and thermodynamic consequences for the 5f series

    International Nuclear Information System (INIS)

    Samhoun, K.

    1976-01-01

    The amalgamation of 5f elements from Am to Fm has been studied by using 241 Am, 244 Cm, 249 Bk, 249 Cf, 252 Cf, 253 Es, 254 Es, 252 Fm and 255 Fm with two electrochemical methods, radiocoulometry and radiopolarography, perfectly adapted to investigate extremely diluted solutions when the concentration of electroactive species is as low as 10 -16 M. The theory of radiocoulometry has been developed in the general cases of reversible and irreversible electrode process. It has been used to interpret the experimental data on the kinetic curves of amalgamation, and to estimate the standard rate constant of the electrode process in complexing medium (citric). On the other hand the radiopolarographic method has been applied to study the mechanism of reduction at the dropping mercury electrode of cations M 3+ in aqueous medium to the metal M with formation of amalgam. The results are exploited into two directions: 1- Acquisition of some data concerning the oxidation-reduction properties of elements from Am to Fm. Therefore the standard electrode E 0 [M(III-0)] potentials for Bk, Cf and Es, and the standard electrode E 0 [M(II-0)] potential for Fm are estimated and the relative stability of each oxidation state (from II to VII) of 5f elements is discussed; 2- Acquisition of unknown thermodynamic data on transcalifornium elements. Correlations between 4f and 5f elements are precised and some divergences appear for the second half of 4f and 5f series (i.e. for 65 [fr

  19. Quantum-chemical consideration of extermal valent forms of actinides

    International Nuclear Information System (INIS)

    Ionova, G.V.; Pershina, V.G.; Spitsyn, V.I.

    1982-01-01

    Stability of valent forms of actinides that has not yet studied experimentally, is considered within the framework of quantum-chemical considerations. Oxidizing potentials E 0 for actinide elements are determined theoretically. A dependence of the definite valent state stability on relativistic effect is shown. A conclusion is made that oxidizing potential E 0 (4-5) for americium should be higher than E 0 (4-5) for plutonium. A relatively small oxidizing potential E 0 (4-5) for curium speaks about principle possibility of production of five-valent curium in solution, though it is less stable than the six-valent one. Oxidizing potential corresponding to transition of three-valent californium into the four-valent state should be less than the value adopted in literature. A relatively small oxidizing potential of californium E 0 (4-5) speaks about possible existence of five-valent californium in solution

  20. Analysis of large soil samples for actinides

    Science.gov (United States)

    Maxwell, III; Sherrod, L [Aiken, SC

    2009-03-24

    A method of analyzing relatively large soil samples for actinides by employing a separation process that includes cerium fluoride precipitation for removing the soil matrix and precipitates plutonium, americium, and curium with cerium and hydrofluoric acid followed by separating these actinides using chromatography cartridges.

  1. Burn of actinides in MOX fuel cells

    International Nuclear Information System (INIS)

    Martinez C, E.; Ramirez S, J. R.; Alonso V, G.

    2017-09-01

    The spent fuel from nuclear reactors is stored temporarily in dry repositories in many countries of the world. However, the main problem of spent fuel, which is its high radio-toxicity in the long term, is not solved. A new strategy is required to close the nuclear fuel cycle and for the sustain ability of nuclear power generation, this strategy could be the recycling of plutonium to obtain more energy and recycle the actinides generated during the irradiation of the fuel to transmute them in less radioactive radionuclides. In this work we evaluate the quantities of actinides generated in different fuels and the quantities of actinides that are generated after their recycling in a thermal reactor. First, we make a reference calculation with a regular enriched uranium fuel, and then is changed to a MOX fuel, varying the plutonium concentrations and determining the quantities of actinides generated. Finally, different amounts of actinides are introduced into a new fuel and the amount of actinides generated at the end of the fuel burn is calculated, in order to determine the reduction of minor actinides obtained. The results show that if the concentration of plutonium in the fuel is high, then the production of minor actinides is also high. The calculations were made using the cell code CASMO-4 and the results obtained are shown in section 6 of this work. (Author)

  2. Environmental chemistry of the actinide elements

    International Nuclear Information System (INIS)

    Rao Linfeng

    1986-01-01

    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

  3. Preliminary Study for Inventories of Minor Actinides in Thorium Molten Salt Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Choong Wie; Kim, Hee Reyoung [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2015-05-15

    It has different characteristic with the conventional reactors which use a solid fuel. It can continually supply the fuel by online refueling and reprocessing of minor actinides so that those can be separated and eliminated from the reactor. The MSR maintains steady state except initial stage and the reactor becomes stable. In this research, considering online refueling, bubbling and reprocessing, the basic concept for evaluation of the inventory of minor actinide in the molten salt reactor is driven using the Bateman equation. The simulation results, where REM and MCNP code from CNRS (Centre National de la Recherche Scientifique) applied to the concept equation are analyzed. The analysis of the basic concept was carried out for evaluation of the inventory of the minor actinides in MSR. It was thought that the inventories of the minor actinides should be evaluated by solving the modified Bateman equation due to the MSR characteristic of online refueling, chemical reprocessing and bubbling.

  4. Handbook on the physics and chemistry of rare earths: Volume 19: Lanthanides/Actinides: Physics, 2

    International Nuclear Information System (INIS)

    Gschneidner, Karl A.; Eyring, LeRoy; Choppin, G.R.; Lander, G.H.

    1994-01-01

    This handbook comprises five chapters on the lanthanide and actinide materials. In the first chapter the inelastic neutron scattering behaviors of the lanthanides and actinides are compared. In the next chapter the focus is on neutron scattering by heavy fermion single crystal materials, including metallic materials with a paramagnetic ground state, superconductors, metallic and semiconducting antiferromagnets and nearly insulating paramagnets. In chapter three a comprehensive review of intermediate valence and heavy fermions in a wide variety of lanthanide and actinide compounds is given, ranging from metallic to insulating materials. In chapter four two issues on the high pressure behaviours of anomalous cerium, ytterbium and uranium compounds are dealt with. In the final chapter an extensive review is given the thermodynamic properties of lanthanide and actinide metallic systems

  5. Preliminary Study for Inventories of Minor Actinides in Thorium Molten Salt Reactor

    International Nuclear Information System (INIS)

    Lee, Choong Wie; Kim, Hee Reyoung

    2015-01-01

    It has different characteristic with the conventional reactors which use a solid fuel. It can continually supply the fuel by online refueling and reprocessing of minor actinides so that those can be separated and eliminated from the reactor. The MSR maintains steady state except initial stage and the reactor becomes stable. In this research, considering online refueling, bubbling and reprocessing, the basic concept for evaluation of the inventory of minor actinide in the molten salt reactor is driven using the Bateman equation. The simulation results, where REM and MCNP code from CNRS (Centre National de la Recherche Scientifique) applied to the concept equation are analyzed. The analysis of the basic concept was carried out for evaluation of the inventory of the minor actinides in MSR. It was thought that the inventories of the minor actinides should be evaluated by solving the modified Bateman equation due to the MSR characteristic of online refueling, chemical reprocessing and bubbling

  6. Review and needs in actinide chemistry in relation with biological purposes

    Energy Technology Data Exchange (ETDEWEB)

    Ansoborlo, E.; Moulin, V.; Bion, L.; Doizi, D.; Moulin, C.; Cote, G.; Madic, C.; Van der Lee, J

    2004-07-01

    In case of accidental release of radionuclides in the environment, actinides could occur and may present an healthy risk for human beings. In order to study their behavior in human organism (metabolism, retention, excretion), it is of prime importance to know solution actinide chemistry, and more particularly thermodynamic constants, which will allow to determine their speciation: speciation governs biological availability and toxicity of elements and is also of great interest for decorporation purposes. In this framework, a CEA working group on speciation has been created in order to share data both on thermodynamic constants and on speciation analytical methods, interesting chemists, environmentalists and biologists. It has been focused, in a first time, on actinides. The purpose of this paper is to present the state of the art on actinide speciation within biological media and to focus on the lack of information in order to orientate future research. (authors)

  7. Minor Actinides Recycling in PWRs

    International Nuclear Information System (INIS)

    Delpech, M.; Golfier, H.; Vasile, A.; Varaine, F.; Boucher, L.; Greneche, D.

    2006-01-01

    Recycling of minor actinides in current and near future PWR is considered as one of the options of the general waste management strategy. This paper presents the analysis of this option both from the core physics and fuel cycle point of view. A first indicator of the efficiency of different neutron spectra for transmutation purposes is the capture to fission cross sections ratio which is less favourable by a factor between 5 to 10 in PWRs compared to fast reactors. Another indicator presented is the production of high ranking isotopes like Curium, Berkelium or Californium in the thermal or epithermal spectrum conditions of PWR cores by successive neutron captures. The impact of the accumulation of this elements on the fabrication process of such PWR fuels strongly penalizes this option. The main constraint on minor actinides loadings in PWR (or fast reactors) fuels are related to their direct impact (or the impact of their transmutation products) on the reactivity coefficients, the reactivity control means and the core kinetics parameters. The main fuel cycle physical parameters like the neutron source, the alpha decay power, the gamma and neutrons dose rate and the criticality aspects are also affected. Recent neutronic calculations based on a reference core of the Evolutionary Pressurized Reactor (EPR), indicates typical maximum values of 1 % loadings. Different fuel design options for minor actinides transmutation purposes in PWRs are presented: UOX and MOX, homogeneous and heterogeneous assemblies. In this later case, Americium loading is concentrated in specific pins of a standard UOX assembly. Recycling of Neptunium in UOX and MOX fuels was also studied to improve the proliferation resistance of the fuel. The impact on the core physics and penalties on Uranium enrichment were underlined in this case. (authors)

  8. Correlation consistent basis sets for actinides. I. The Th and U atoms

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, Kirk A., E-mail: kipeters@wsu.edu [Department of Chemistry, Washington State University, Pullman, Washington 99164-4630 (United States)

    2015-02-21

    New correlation consistent basis sets based on both pseudopotential (PP) and all-electron Douglas-Kroll-Hess (DKH) Hamiltonians have been developed from double- to quadruple-zeta quality for the actinide atoms thorium and uranium. Sets for valence electron correlation (5f6s6p6d), cc − pV nZ − PP and cc − pV nZ − DK3, as well as outer-core correlation (valence + 5s5p5d), cc − pwCV nZ − PP and cc − pwCV nZ − DK3, are reported (n = D, T, Q). The -PP sets are constructed in conjunction with small-core, 60-electron PPs, while the -DK3 sets utilized the 3rd-order Douglas-Kroll-Hess scalar relativistic Hamiltonian. Both series of basis sets show systematic convergence towards the complete basis set limit, both at the Hartree-Fock and correlated levels of theory, making them amenable to standard basis set extrapolation techniques. To assess the utility of the new basis sets, extensive coupled cluster composite thermochemistry calculations of ThF{sub n} (n = 2 − 4), ThO{sub 2}, and UF{sub n} (n = 4 − 6) have been carried out. After accurately accounting for valence and outer-core correlation, spin-orbit coupling, and even Lamb shift effects, the final 298 K atomization enthalpies of ThF{sub 4}, ThF{sub 3}, ThF{sub 2}, and ThO{sub 2} are all within their experimental uncertainties. Bond dissociation energies of ThF{sub 4} and ThF{sub 3}, as well as UF{sub 6} and UF{sub 5}, were similarly accurate. The derived enthalpies of formation for these species also showed a very satisfactory agreement with experiment, demonstrating that the new basis sets allow for the use of accurate composite schemes just as in molecular systems composed only of lighter atoms. The differences between the PP and DK3 approaches were found to increase with the change in formal oxidation state on the actinide atom, approaching 5-6 kcal/mol for the atomization enthalpies of ThF{sub 4} and ThO{sub 2}. The DKH3 atomization energy of ThO{sub 2} was calculated to be smaller than the DKH2

  9. PIE analysis for minor actinide

    International Nuclear Information System (INIS)

    Suyama, Kenya

    2005-01-01

    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)

  10. Catalytic Organic Transformations Mediated by Actinide Complexes

    Directory of Open Access Journals (Sweden)

    Isabell S. R. Karmel

    2015-10-01

    Full Text Available This review article presents the development of organoactinides and actinide coordination complexes as catalysts for homogeneous organic transformations. This chapter introduces the basic principles of actinide catalysis and deals with the historic development of actinide complexes in catalytic processes. The application of organoactinides in homogeneous catalysis is exemplified in the hydroelementation reactions, such as the hydroamination, hydrosilylation, hydroalkoxylation and hydrothiolation of alkynes. Additionally, the use of actinide coordination complexes for the catalytic polymerization of α-olefins and the ring opening polymerization of cyclic esters is presented. The last part of this review article highlights novel catalytic transformations mediated by actinide compounds and gives an outlook to the further potential of this field.

  11. Basic actinide chemistry and physics research in close cooperation with hot laboratories: ACTILAB

    International Nuclear Information System (INIS)

    Minato, K; Konashi, K; Fujii, T; Uehara, A; Nagasaki, S; Ohtori, N; Tokunaga, Y; Kambe, S

    2010-01-01

    Basic research in actinide chemistry and physics is indispensable to maintain sustainable development of innovative nuclear technology. Actinides, especially minor actinides of americium and curium, need to be handled in special facilities with containment and radiation shields. To promote and facilitate actinide research, close cooperation with the facilities and sharing of technical and scientific information must be very important and effective. A three-year-program B asic actinide chemistry and physics research in close cooperation with hot laboratories , ACTILAB, was started to form the basis of sustainable development of innovative nuclear technology. In this program, research on actinide solid-state physics, solution chemistry and solid-liquid interface chemistry is made using four main facilities in Japan in close cooperation with each other, where basic experiments with transuranium elements can be made. The 17 O-NMR measurements were performed on (Pu 0.91 Am 0.09 )O 2 to study the electronic state and the chemical behaviour of Am and Cm ions in electrolyte solutions was studied by distribution experiments.

  12. Adsorption of actinides by chelating agents containing benzene rings, fixed on charcoal

    International Nuclear Information System (INIS)

    Valentini Ganzerli, M.T.; Crespi Caramella, V.; Maggi, L.

    1999-01-01

    The focus of this paper is on the analysis of the actinides in the hydrosphere to study their environmental dispersion. The 8-hydroxyquinoline family and the benzohydroxamic acid have a complexing ability towards the actinides, even if in different oxidation states. Taking advantage of this ability, their salts with some organic acids or bases were prepared. In this way compounds were obtained easily incorporated into active charcoal. Only a small amount of the prepared adsorber may be equilibrated with large sample volumes. Subsequently it can be recovered by filtration. The adsorbed ions may be then re-dissolved with a small volume of the appropriate eluting solution. The 8-hydroxy-quinolines and the 8-hydroxyquinoline produced salts with the benzilic acid. These compounds similarly behave and show wide adsorption coefficients for solutions of pH higher than 3. The adsorption takes place by means of the formation of a complex of the actinide ion with the hydroxyquinoline moiety and also with the benzilic anion. Provided that the active extracting agent is not dissolved in a medium but fixed into a solid phase, the whole adsorption process may be regarded as a solvent extraction reaction. The benzohydroxamic acid was treated with the diphenylamine or with the tribenzylamine to obtain salts, later adsorbed into the charcoal. The adsorption of actinide ions seems to take place by means of a precipitation mechanism of the actinide ions with the hydroxamate ions for solution of pH higher than 3.5. Also in this case high values were obtained for the distribution coefficients. The actinide ions act similarly in the +4 or +6 oxidation state towards the prepared adsorber series. Therefore, it is possible to use only one adsorber to concentrate all actinides. Methods of analysis of actinides in the environment may be suitably set up and the concentration step based on these new prepared adsorber may improve the whole procedure. (authors)

  13. Theoretical Studies of the Electronic Structure of the Compounds of the Actinide Elements

    International Nuclear Information System (INIS)

    Kaltsoyannis, Nikolas; Hay, P.J.; Li, Jun; Blaudeau, Jean-Philippe; Bursten, Bruce E.

    2006-01-01

    In this chapter, we will present an overview of the theoretical and computational developments that have increased our understanding of the electronic structure of actinide-containing molecules and ions. The application of modern electronic structure methodologies to actinide systems remains one of the great challenges in quantum chemistry; indeed, as will be discussed below, there is no other portion of the periodic table that leads to the confluence of complexity with respect to the calculation of ground- and excited-state energies, bonding descriptions, and molecular properties. But there is also no place in the periodic table in which effective computational modeling of electronic structure can be more useful. The difficulties in creating, isolating, and handling many of the actinide elements provide an opportunity for computational chemistry to be an unusually important partner in developing the chemistry of these elements. The importance of actinide electronic structure begins with the earliest studies of uranium chemistry and predates the discovery of quantum mechanics. The fluorescence of uranyl compounds was observed as early as 1833, a presage of the development of actinometry as a tool for measuring photochemical quantum yields. Interest in nuclear fuels has stimulated tremendous interest in understanding the properties, including electronic properties, of small actinide-containing molecules and ions, especially the oxides and halides of uranium and plutonium. The synthesis of uranocene in 1968 led to the flurry of activity in the organometallic chemistry of the actinides that continues today. Actinide organometallics (or organoactinides) are nearly always molecular systems and are often volatile, which makes them amenable to an arsenal of experimental probes of molecular and electronic structure (Marks and Fischer, 1979). Theoretical and computational studies of the electronic structure of actinide systems have developed in concert with the experimental

  14. A systematic analysis of the spectra of trivalent actinide chlorides in D3h site symmetry

    International Nuclear Information System (INIS)

    Carnall, W.T.

    1989-11-01

    The optical spectra of actinide ions in the compound AnCl 3 and doped into single crystal LaCl 3 were interpreted in terms of transitions within 5f N configurations. Energy-level calculations were carried out using an effective operator Hamiltonian, the parameters of which were determined by fitting experimental data. Atomic and crystal-field matrices were diagonalized simultaneously assuming an approximate D 3h site symmetry. The spectroscopic data were taken from the literature but in most cases supplemented by unpublished measurements in absorption and in fluorescence. Spectroscopic data for each ion were analyzed independently, then the model parameters were intercompared and in many cases adjusted such that in the final fitting process the principal interactions showed uniform trends in parameter values with increasing atomic number. Consistent with analyses of the spectra of lanthanide ions in both LaCl 3 and LaF 3 , abrupt changes in magnitude of certain crystal-field parameters were found near the center of the 5f N -series. This resulted in two groups of parameter values, but with consistent trends for both halves of the series, and generally very good agreement between observed and computed energies. A new energy level chart based on computed crystal-field level energies for each trivalent actinide ion has been prepared. in addition, the parameters of the atomic part of each 5f N Hamiltonian were used to calculate the matrix elements of U (λ) for selected transitions. The values were tabulated to facilitate calculation of intensity-related parameters for 5f N -transitions using the Judd-Ofelt theory. 44 refs., 10 figs., 3 tabs

  15. Development of Metallic Fuels for Actinide Transmutation

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, Steven Lowe [Idaho National Laboratory; Fielding, Randall Sidney [Idaho National Laboratory; Benson, Michael Timothy [Idaho National Laboratory; Chichester, Heather Jean MacLean [Idaho National Laboratory; Carmack, William Jonathan [Idaho National Laboratory

    2015-09-01

    and 60%. In general, the performance of all of these substantially disparate metallic fuel alloys has been observed to be excellent, and their irradiation behaviors are generally consistent with historic norms for metallic fuels without minor actinide additions and having lower Pu or Zr contents. Future work is being undertaken with a view toward increasing the burnup potential of metallic fuels even more. Design innovations under investigation include: 1) lowering the fuel smear density in order to accommodate more swelling, 2) annular fuel geometry to eliminate the need for a sodium bond, 3) minor alloy additions to stabilize lanthanide fission products inside the fuel and prevent their transport to the cladding where they can participate in fuel-cladding chemical interaction (FCCI), and 4) coatings/liners on the cladding inner surface to mitigate FCCI and enable higher temperature operation. This paper will present the current state of development of metallic fuels for actinide transmutation in the US. Highlights will include recent results from metallic fuel casting experiments, experiments to identify alloy additions to immobilize lanthanide fission products, and postirradiation examinations of annular metallic fuels at low burnup.

  16. 1982 Annual Status Report Plutonium Fuels and Actinide Programme

    International Nuclear Information System (INIS)

    Lindner, R.

    1983-01-01

    The programme of the Transuranium Institute has long included work on advanced fuels for fast breeder reactors. Study of the swelling of carbide and nitride fuels is now nearing completion, the retention of fission gases in bubbles of different sizes in the fuel having been quantified as function of burn-up and temperature. An important step forward has been achieved in the studies of the Equation of State of Nuclear Fuels up to 5000 K. Formation of some of the less abundant isotopes in PWR fuel has been determined experimentally. Aerosol formation during the fabrication of plutonium containing fuels, part of the activity Safe Handling of Plutonium Fuel has been studied. Head-End Processing of carbide fuels has continued experiments with high burn up mixed carbides. In the field of actinide research the preparation and characterisation of pure specimens is carried out. Effect of actinides on the properties of waste glasses is investigated

  17. Magnetic form factor of NpAs2: a crystal field wave function for 5f electrons

    International Nuclear Information System (INIS)

    Amoretti, G.; Blaise, A.; Bonnet, M.; Boucherle, J.X.; Delapalme, A.; Fournier, J.M.; Vigneron, F.

    1982-10-01

    Neptunium magnetic form factor measurements in the ferromagnetic phase of NpAs 2 (T = 4.2 K, H = 4.6 T) are analysed under different assumptions: Np 3 + , Np 4 + or Np 5 + , with a free ion wave-function (Russel-Saunders and intermediate coupling scheme) or with a Crystal Field Wave function for 5f electrons: sub(m)sup(μ)asub(m)asub(m)/J,m>. The experimental results are compatible with either a 3+ or 4+ state

  18. M4FT-16LL080303052-State of Knowledge for Colloid Facilitated Radionuclide Transport and Update on Actinide Diffusion in Bentonite Backfill

    Energy Technology Data Exchange (ETDEWEB)

    Zavarin, Mavrik [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Glenn T. Seaborg Inst.. Physical and Life Sciences; Joseph, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Glenn T. Seaborg Inst.. Physical and Life Sciences

    2016-08-16

    This progress report (Level 4 Milestone Number M4FT-16LL080303052) summarizes research conducted at Lawrence Livermore National Laboratory (LLNL) within the Crystalline Disposal R&D Activity Number FT-16LL080303051 and Crystalline International Collaborations Activity Number FT-16LL080303061. The focus of this research is the interaction of radionuclides with Engineered Barrier System (EBS) and host rock materials at various physico-chemical conditions relevant to subsurface repository environments. They include both chemical and physical processes such as solubility, sorption, and diffusion. The colloid-facilitated transport effort focused on preparation of a draft manuscript summarizing the state of knowledge and parameterization of colloid-facilitated transport mechanisms in support of reactive transport and performance assessment models for generic crystalline repositories. This draft manuscript is being submitted as a level 3 milestone with LANL as the primary author. LLNL’s contribution to that effort is summarized only briefly in the present report. A manuscript summarizing long-term U(VI) diffusion experiments through bentonite backfill material was recently accepted for publication; the contents of that manuscript are summarized in the present report. The Np(IV) diffusion experiments were started mid-year and are ongoing. The completion of these experiments is planned for early FY17. Our progress in quantifying Np(IV) diffusion in bentonite backfill is summarized in the present report. Our involvement with the NEA TDB project was summarized in a recent Argillite Disposal activity report. It is not included in this report.

  19. Minor actinide transmutation - a waste management option

    International Nuclear Information System (INIS)

    Koch, L.

    1986-01-01

    The incentive to recycle minor actinides results from the reduction of the long-term α-radiological risk rather than from a better utilization of the uranium resources. Nevertheless, the gain in generated electricity by minor actinide transmutation in a fast breeder reactor can compensate for the costs of their recovery and make-up into fuel elements. Different recycling options of minor actinides are discussed: transmutation in liquid metal fast breeder reactors (LMFBRs) is possible as long as plutonium is not recycled in light water reactors (LWRs). In this case a minor actinide burner with fuel of different composition has to be introduced. The development of appropriate minor actinide fuels and their properties are described. The irradiation experiments underway or planned are summarized. A review of minor actinide partitioning from the PUREX waste stream is given. From the present constraints of LMFBR technology a reduction of the long-term α-radiological risk by a factor of 200 is deduced relative to that from the direct storage of spent LWR fuel. Though the present accumulation of minor actinides is low, nuclear transmutation may be needed when nuclear energy production has grown. (orig.)

  20. Criteria for achieving actinide reduction goals

    International Nuclear Information System (INIS)

    Liljenzin, J.O.

    1996-01-01

    In order to discuss various criteria for achieving actinide reduction goals, the goals for actinide reduction must be defined themselves. In this context the term actinides is interpreted to mean plutonium and the so called ''minor actinides'' neptunium, americium and curium, but also protactinium. Some possible goals and the reasons behind these will be presented. On the basis of the suggested goals it is possible to analyze various types of devices for production of nuclear energy from uranium or thorium, such as thermal or fast reactors and accelerator driven system, with their associated fuel cycles with regard to their ability to reach the actinide reduction goals. The relation between necessary single cycle burn-up values, fuel cycle processing losses and losses to waste will be defined and discussed. Finally, an attempt is made to arrange the possible systems on order of performance with regard to their potential to reduce the actinide inventory and the actinide losses to wastes. (author). 3 refs, 3 figs, 2 tabs

  1. Actinides burnup in a sodium fast reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez S, J. R.; Pineda A, R.; Martinez C, E.; Alonso, G., E-mail: ramon.ramirez@inin.gob.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2017-09-15

    The burnup of actinides in a nuclear reactor is been proposed as part of an advanced nuclear fuel cycle, this process would close the fuel cycle recycling some of the radioactive material produced in the open nuclear fuel cycle. These actinides are found in the spent nuclear fuel from nuclear power reactors at the end of their burnup in the reactor. Previous studies of actinides recycling in thermal reactors show that would be possible reduce the amounts of actinides at least in 50% of the recycled amounts. in this work, the amounts of actinides that can be burned in a fast reactor is calculated, very interesting results surge from the calculations, first, the amounts of actinides generated by the fuel is higher than for thermal fuel and the composition of the actinides vector is different as in fuel for thermal reactor the main isotope is the {sup 237}Np in the fuel for fast reactor the main isotope is the {sup 241}Am, finally it is concluded that the fast reactor, also generates important amounts of waste. (Author)

  2. Actinides and the environment: what we know and what we need to know

    International Nuclear Information System (INIS)

    Nitsche, H.

    1998-01-01

    In order to design methods for the cleanup of contaminated sites, predict the transport behavior in the environment, perform safety assessment studies to determine the ability of repositories to adequately contain them, and design ways to retard their release and migration rates, it is essential to understand the chemical behavior and forms of actinides under environmental conditions. Excluding gaseous and airborne transport, actinides can migrate in the environment mostly via aqueous media such as groundwater and surface, river, lake and sea water. Models predicting the hydrological transport through the environment require as input an actinide concentration, the true amount that is actually available for transport. It is defined as the actinide source term and not as true solubility, because it may be a combination of dissolved and colloidal material. Three major processes define the actinide source term: (1) solubility, (2) organic interaction, and (3) sorption. They are dependent on each other and each individual process is the result of several sub-processes. Also, colloid formation plays a major role in the actinide source term, and it is common to each of the three main processes. The current state of knowledge of these processes will be discussed and areas will be outlined where additional information is required

  3. Enhancing the actinide sciences in Europe through hot laboratories networking and pooling: from ACTINET to TALISMAN

    International Nuclear Information System (INIS)

    Bourg, S.; Poinssot, C.

    2013-01-01

    Since 2004, Europe supports the strengthening of the European actinides sciences scientific community through the funding of dedicated networks: (i) from 2004 to 2008, the ACTINET6 network of excellence (6. Framework Programme) gathered major laboratories involved in nuclear research and a wide range of academic research organisations and universities with the specific aims of funding and implementing joint research projects to be performed within the network of pooled facilities; (ii) from 2009 to 2013, the ACTINET-I3 integrated infrastructure initiative (I3) supports the cost of access of any academics in the pooled EU hot laboratories. In this continuation, TALISMAN (Trans-national Access to Large Infrastructures for a Safe Management of Actinides) gathers now the main European hot laboratories in actinides sciences in order to promote their opening to academics and universities and strengthen the EU-skills in actinides sciences. Furthermore, a specific focus is set on the development of advanced cutting-edge experimental and spectroscopic capabilities, the combination of state-of-the art experimental with theoretical first-principle methods on a quantum mechanical level and to benefit from the synergy between the different scientific and technical communities. ACTINET-I3 and TALISMAN attach a great importance and promote the Education and Training of the young generation of actinides scientists in the Trans-national access but also by organizing Schools (general Summer Schools or Theoretical User Lab Schools) or by granting students to attend International Conference on actinide sciences. (authors)

  4. Experimental studies of actinides in molten salts

    International Nuclear Information System (INIS)

    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

  5. Experimental studies of actinides in molten salts

    Energy Technology Data Exchange (ETDEWEB)

    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.

  6. Neutron nuclear data evaluation for actinide nucleic

    International Nuclear Information System (INIS)

    Chen Guochang; Yu Baosheng; Duan Junfeng; Ge Zhigang; Cao Wentian; Tang Guoyou; Shi Zhaomin; Zou Yubin

    2010-01-01

    The nuclear data with high accuracy for minor actinides are playing an important role in nuclear technology applications, including reactor design and operation, fuel cycle concepts, estimation of the amount of minor actinides in high burn-up reactors and the minor actinides transmutation. Through describe the class of nuclear data and nuclear date library, and introduce the procedure of neutron nuclear data evaluation. 234 U(n, f) and 237 Np(n, 2n) reaction experimental data evaluation was evaluated. The fission nuclear data are updated and improved. (authors)

  7. Actinide chemistry in the far field

    International Nuclear Information System (INIS)

    Livens, F.R.; Morris, K.; Parkman, R.; Moyes, L.

    1996-01-01

    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)

  8. Superconductivity in REO0.5F0.5BiS2 with high-entropy-alloy-type blocking layers

    Science.gov (United States)

    Sogabe, Ryota; Goto, Yosuke; Mizuguchi, Yoshikazu

    2018-05-01

    We synthesized new REO0.5F0.5BiS2 (RE: rare earth) superconductors with high-entropy-alloy-type (HEA-type) REO blocking layers. The lattice constant a systematically changed in the HEA-type samples with the RE concentration and the RE ionic radius. A sharp superconducting transition was observed in the resistivity measurements for all the HEA-type samples, and the transition temperature of the HEA-type samples was higher than that of typical REO0.5F0.5BiS2. The sharp superconducting transition and the enhanced superconducting properties of the HEA-type samples may indicate the effectiveness of the HEA states of the REO blocking layers in the REO0.5F0.5BiS2 system.

  9. Chemical aspects of actinides in the geosphere: towards a rational nuclear materials management

    International Nuclear Information System (INIS)

    Allen, P; Sylwester, E

    2001-01-01

    A complete understanding of actinide interactions in the geosphere is paramount for developing a rational Nuclear and Environmental Materials Management Policy. One of the key challenges towards understanding the fate and transport of actinides is determining their speciation (i.e., oxidation state and structure). Since an element's speciation directly dictates physical properties such as toxicity and solubility, this information is critical for evaluating and controlling the evolution of an actinide element through the environment. Specific areas within nuclear and environmental management programs where speciation is important are (1) waste processing and separations; (2) wasteform materials for long-term disposition; and (3) aqueous geochemistry. The goal of this project was to develop Actinide X-ray Absorption Spectroscopy ( U S ) as a core capability at LLNL and integrate it with existing facilities, providing a multi-technique approach to actinide speciation. XAS is an element-specific structural probe which determines the oxidation state and structure for most atoms. XAS can be more incisive than other spectroscopies because it originates from an atomic process and the information is always attainable, regardless of an element's speciation. Despite the utility, XAS is relatively complex due to the need for synchrotron radiation and significant expertise with data acquisition and analysis. The coupling of these technical hurdles with the safe handling of actinides at a general user synchrotron facility such as the Stanford Synchrotron Radiation Facility (SSRL) make such experiments even more difficult. As a result, XAS has been underutilized by programs that could benefit by its application. We achieved our project goals by implementing key state-of-the-art Actinide XAS instrumentation at SSRL (Ge detector and remote positioning equipment), and by determining the chemical speciation of actinides (Th, U, and Np) in aqueous solutions, wasteform cements, and

  10. Influence of a Heterocyclic Nitrogen-Donor Group on the Coordination of Trivalent Actinides and Lanthanides by Aminopolycarboxylate Complexants.

    Science.gov (United States)

    Grimes, Travis S; Heathman, Colt R; Jansone-Popova, Santa; Ivanov, Alexander S; Roy, Santanu; Bryantsev, Vyacheslav S; Zalupski, Peter R

    2018-02-05

    The novel metal chelator N-2-(pyridylmethyl)diethylenetriamine-N,N',N″,N″-tetraacetic acid (DTTA-PyM) was designed to replace a single oxygen-donor acetate group of the well-known aminopolycarboxylate complexant diethylenetriamine-N,N,N',N″,N″-pentaacetic acid (DTPA) with a nitrogen-donor 2-pyridylmethyl. Potentiometric, spectroscopic, computational, and radioisotope distribution methods show distinct differences for the 4f and 5f coordination environments and enhanced actinide binding due to the nitrogen-bearing heterocyclic moiety. The Am 3+ , Cm 3+ , and Ln 3+ complexation studies for DTTA-PyM reveal an enhanced preference, relative to DTPA, for trivalent actinide binding. Fluorescence studies indicate no changes to the octadentate coordination of trivalent curium, while evidence of heptadentate complexation of trivalent europium is found in mixtures containing EuHL (aq) complexes at the same aqueous acidity. The denticity change observed for Eu 3+ suggests that complex protonation occurs on the pyridyl nitrogen. Formation of the CmHL (aq) complex is likely due to the protonation of an available carboxylate group because the carbonyl oxygen can maintain octadentate coordination through a rotation. The observed suppressed protonation of the pyridyl nitrogen in the curium complexes may be attributed to stronger trivalent actinide binding by DTTA-PyM. Density functional theory calculations indicate that added stabilization of the actinide complexes with DTTA-PyM may originate from π-back-bonding interactions between singly occupied 5f orbitals of Am 3+ and the pyridyl nitrogen. The differences between the stabilities of trivalent actinide chelates (Am 3+ , Cm 3+ ) and trivalent lanthanide chelates (La 3+ -Lu 3+ ) are observed in liquid-liquid extraction systems, yielding unprecedented 4f/5f differentiation when using DTTA-PyM as an aqueous holdback reagent. In addition, the enhanced nitrogen-donor softness of the new DTTA-PyM chelator was perturbed by

  11. Actinide recovery from pyrochemical residues

    International Nuclear Information System (INIS)

    Avens, L.R.; Clifton, D.G.; Vigil, A.R.

    1984-01-01

    A new process for recovery of plutonium and americium from pyrochemical waste has been demonstrated. It is based on chloride solution anion exchange at low acidity, which eliminates corrosive HCl fumes. Developmental experiments of the process flowsheet concentrated on molten salt extraction (MSE) residues and gave >95% plutonium and >90% americium recovery. The recovered plutonium contained 6 = from high chloride-low acid solution. Americium and other metals are washed from the ion exchange column with 1N HNO 3 -4.8M NaCl. The plutonium is recovered, after elution, via hydroxide precipitation, while the americium is recovered via NaHCO 3 precipitation. All filtrates from the process are discardable as low-level contaminated waste. Production-scale experiments are now in progress for MSE residues. Flow sheets for actinide recovery from electrorefining and direct oxide reduction residues are presented and discussed

  12. Actinide recovery from pyrochemical residues

    International Nuclear Information System (INIS)

    Avens, L.R.; Clifton, D.G.; Vigil, A.R.

    1985-05-01

    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 6 2- from high-chloride low-acid solution. Americium and other metals are washed from the ion exchange column with lN HNO 3 -4.8M NaCl. After elution, plutonium is recovered by hydroxide precipitation, and americium is recovered by NaHCO 3 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

  13. A first principles investigation of the electronic structure of actinide oxides

    DEFF Research Database (Denmark)

    Petit, Leon; Svane, Axel; Szotek, Zdzislawa

    2010-01-01

    The ground state electronic structures of the actinide oxides AO, A2O3 and AO2 (A=U, Np, Pu, Am, Cm, Bk, Cf) are determined from first-principles calculations using the selfinteraction corrected local spin-density approximation. Our study reveals a strong link between preferred oxidation number...... and degree of localization. The ionic nature of the actinide oxides emerges from the fact that those oxides where the ground state is calculated to be metallic do not exist in nature, as the corresponding delocalized f-states favour the accommodation of additional O atoms into the crystal lattice....

  14. Itinerant 5f electrons and the Fermi surface properties in neptunium compounds

    International Nuclear Information System (INIS)

    Aoki, D.; Yamagami, H.; Homma, Y.; Sakai, H.; Ikeda, S.; Shiokawa, Y.; Yamamoto, E.; Nakamura, A.; Haga, Y.; Settai, R.; Onuki, Y.

    2007-01-01

    We grew high-quality single crystals of NpGe 3 , NpIn 3 , NpCoGa 5 , NpRhGa 5 and NpFe 4 P 12 by the flux method, and measured the de Haas-van Alphen (dHvA) effect, magnetic susceptibility and resistivity. The results of dHvA experiments in NpGe 3 , NpCoGa 5 and NpRhGa 5 were well explained by the energy band calculation based on the 5f-itinerant model, while the topology of Fermi surfaces in NpIn 3 is similar to those of LaIn 3 , implying the 5f-localized nature of NpIn 3 . The skutterudite compound NpFe 4 P 12 is a low carrier system with the 5f 3 configuration

  15. A literature review of actinide-carbonate mineral interactions

    International Nuclear Information System (INIS)

    Stout, D.L.

    1993-10-01

    Chemical retardation of actinides in groundwater systems is a potentially important mechanism for assessing the performance of the Waste Isolation Pilot Plant (WIPP), a facility intended to demonstrate safe disposal of transuranic waste. Rigorous estimation of chemical retardation during transport through the Culebra Dolomite, a water-bearing unit overlying the WIPP, requires a mechanistic understanding of chemical reactions between dissolved elements and mineral surfaces. This report represents a first step toward this goal by examining the literature for pertinent experimental studies of actinide-carbonate interactions. A summary of existing models is given, along with the types of experiments on which these models are based. Articles pertaining to research into actinide interactions with carbonate minerals are summarized. Select articles involving trace element-carbonate mineral interactions are also reviewed and may serve as templates for future research. A bibliography of related articles is included. Americium(III), and its nonradioactive analog neodymium(III), partition strongly from aqueous solutions into carbonate minerals. Recent thermodynamic, kinetic, and surface studies show that Nd is preferentially removed from solution, forming a Nd-Ca carbonate solid solution. Neptunium(V) is rapidly removed from solution by carbonates. Plutonium incorporation into carbonates is complicated by multiple oxidation states. Little research has been done on the radium(H) and thorium(IV) carbonate systems. Removal of uranyl ion from solution by calcite is limited to monolayer surface coverage

  16. Process analytical chemistry applied to actinide waste streams

    International Nuclear Information System (INIS)

    Day, R.S.

    1994-01-01

    The Department of Energy is being called upon to clean up it's legacy of waste from the nuclear complex generated during the cold war period. Los Alamos National Laboratory is actively involved in waste minimization and waste stream polishing activities associated with this clean up. The Advanced Testing Line for Actinide Separations (ATLAS) at Los Alamos serves as a developmental test bed for integrating flow sheet development of nitric acid waste streams with process analytical chemistry and process control techniques. The wastes require processing in glove boxes because of the radioactive components, thus adding to the difficulties of making analytical measurements. Process analytical chemistry methods provide real-time chemical analysis in support of existing waste stream operations and enhances the development of new waste stream polishing initiatives. The instrumentation and methods being developed on ATLAS are designed to supply near-real time analyses on virtually all of the chemical parameters found in nitric acid processing of actinide waste. These measurements supply information on important processing parameters including actinide oxidation states, free acid concentration, interfering anions and metal impurities

  17. Identification and analytical characterization of six synthetic cannabinoids NNL-3, 5F-NPB-22-7N, 5F-AKB-48-7N, 5F-EDMB-PINACA, EMB-FUBINACA, and EG-018.

    Science.gov (United States)

    Liu, Cuimei; Jia, Wei; Hua, Zhendong; Qian, Zhenhua

    2017-08-01

    Clinical and forensic toxicology laboratories are continuously confronted by analytical challenges when dealing with the new psychoactive substances phenomenon. The number of synthetic cannabinoids, the chemical diversity, and the speed of emergence make this group of compounds particularly challenging in terms of detection, monitoring, and responding. Three indazole 7N positional isomer synthetic cannabinoids, two ethyl 2-amino-3-methylbutanoate-type synthetic cannabinoids, and one 9H-carbazole substituted synthetic cannabinoid were identified in seized materials. These six synthetic cannabinoid derivatives included: 1H-benzo[d] [1,2,3]triazol-1-yl 1-(5-fluoropentyl)-1H-pyrrolo[2,3-b]pyridine-3-carboxylate (NNL-3, 1), quinolin-8-yl 1-(5-fluoropentyl)-1H-pyrrolo[2,3-b]pyridine-3-carboxylate (5F-NPB-22-7N, 2), N-((1 s,3 s)-adamantan-1-yl)-1-(5-fluoropentyl)-1H-pyrrolo[2,3-b]pyridine-3-carboxamide (5F-AKB-48-7N, 3), ethyl 2-(1-(5-fluoropentyl)-1H-indazole-3-carboxamido)-3,3-dimethylbutanoate (5F-EDMB-PINACA, 4), ethyl 2-(1-(4-fluorobenzyl)-1H-indazole-3-carboxamido)-3-methylbutanoate (EMB-FUBINACA, 5), and naphthalen-1-yl(9-pentyl-9H-carbazol-3-yl)methanone (EG-018, 6). The identification was based on ultra-high-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry (UHPLC-QTOF-MS), gas chromatography-mass spectrometry (GC-MS), and nuclear magnetic resonance spectroscopy (NMR). The analytical characterization of these six synthetic cannabinoids was described, so as to assist forensic laboratories in identifying these compounds or other substances with similar structure in their case work. To our knowledge, no analytical data about the compounds 1-5 have appeared until now, making this the first report on these compounds. The GC-MS data of 6 has been reported, but this study added the LC-MS, NMR, and Fourier transform infrared (FTIR), data to render the analytical data collection process more complete. Copyright © 2017 John Wiley & Sons, Ltd

  18. Electronic structure and correlation effects in actinides

    International Nuclear Information System (INIS)

    Albers, R.C.

    1998-01-01

    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

  19. BWR Assembly Optimization for Minor Actinide Recycling

    Energy Technology Data Exchange (ETDEWEB)

    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).

  20. Research for actinides extractants from various wastes

    International Nuclear Information System (INIS)

    Musikas, C.; Cuillerdier, C.; Condamines, N.

    1990-01-01

    This paper is an overview of the actinides solvent extraction research undertaken in Fontenay-aux-Roses. Two kinds of extractants are investigated; those usable for the improvement of the nowadays nuclear fuels reprocessing and those necessary for advanced fuels cycles which include the minor actinides (Np, Am) recovery for a further elimination through nuclear reactions. In the first class the mono and diamides, alternative to the organophosphorus extractants, TBP and polyfunctional phosphonates, showed promising properties. The main results are discussed. For the future efficient extractants for trivalent actinides-lanthanides group separations are suitable. The point about the actinides (III) - lanthanides (III) group separation chemistry and the development of some of these extractants are given

  1. Actinide isotopes in the marine environment

    International Nuclear Information System (INIS)

    Holm, E.; Fukai, R.

    1986-01-01

    Studies of actinide isotopes in the environment are important not only from the viewpoint of their radiological effects on human life, but also from the fact that they act as excellent biochemical and geochemical tracers especially in the marine environment. For several of the actinide isotopes there is still a lack of basic data on concentration levels and further investigations on their chemical and physical speciation are required to understand their behaviour in the marine environment. The measured and estimated activity concentration levels of artificial actinides are at present in general a few orders of magnitude lower than those of the natural ones and their concentration factors in biota are relatively low, except in a few species of macroalgae and phytoplankton. The contribution from seafood to total ingestion of actinides by the world population is a few per cent and, therefore, the dose to man from these long-lived radionuclides caused by seafood ingestion is usually low. (orig.)

  2. Robust membrane systems for actinide separations

    International Nuclear Information System (INIS)

    Jarvinen, Gordon D.; McCleskey, T. Mark; Bluhm, Elizabeth A.; Abney, Kent D.; Ehler, Deborah S.; Bauer, Eve; Le, Quyen T.; Young, Jennifer S.; Ford, Doris K.; Pesiri, David R.; Dye, Robert C.; Robison, Thomas W.; Jorgensen, Betty S.; Redondo, Antonio; Pratt, Lawrence R.; Rempe, Susan L.

    2000-01-01

    Our objective in this project is to develop very stable thin membrane structures containing ionic recognition sites that facilitate the selective transport of target metal ions, especially the actinides

  3. Solid state physics and actinide spectroscopy

    International Nuclear Information System (INIS)

    Delamoye, P.; Hubert, S.; Khan Malek, C.; Krupa, J.C.; Simoni, E.; Genet, M.

    1985-01-01

    We studied the physical and spectroscopic properties of ThBr 4 and ThCl 4 . We made first a synthesis and studied the crystal growth to determinate the Uranium concentration in the crystals. This work allows an interpretation of the optical properties of an ion embedded in an incommensurate structure [fr

  4. Possible existence of backbending in actinide nuclei

    International Nuclear Information System (INIS)

    Dudek, J.; Nazarewicz, W.; Szymanski, Z.

    1982-01-01

    The possibilities for the backbending effect to occur in actinide nuclei are studied using the pairing-self-consistent independent quasiparticle method. The Hamiltonian used is that of the deformed Woods-Saxon potential plus monopole pairing term. The results of the calculations explain why there is no backbending in most actinide nuclei and simultaneously suggest that in some light neutron deficient nuclei around Th and 22 Ra a backbending effect may occur

  5. Lattice effects in the light actinides

    International Nuclear Information System (INIS)

    Lawson, A.C.; Cort, B.; Roberts, J.A.; Bennett, B.I.; Brun, T.O.; Dreele, R.B. von; Richardson, J.W. Jr.

    1998-01-01

    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

  6. Transmutation of actinides in power reactors.

    Science.gov (United States)

    Bergelson, B R; Gerasimov, A S; Tikhomirov, G V

    2005-01-01

    Power reactors can be used for partial short-term transmutation of radwaste. This transmutation is beneficial in terms of subsequent storage conditions for spent fuel in long-term storage facilities. CANDU-type reactors can transmute the main minor actinides from two or three reactors of the VVER-1000 type. A VVER-1000-type reactor can operate in a self-service mode with transmutation of its own actinides.

  7. Predictive Modeling in Actinide Chemistry and Catalysis

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ping [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-16

    These are slides from a presentation on predictive modeling in actinide chemistry and catalysis. The following topics are covered in these slides: Structures, bonding, and reactivity (bonding can be quantified by optical probes and theory, and electronic structures and reaction mechanisms of actinide complexes); Magnetic resonance properties (transition metal catalysts with multi-nuclear centers, and NMR/EPR parameters); Moving to more complex systems (surface chemistry of nanomaterials, and interactions of ligands with nanoparticles); Path forward and conclusions.

  8. Subcritical limits for special fissile actinides

    International Nuclear Information System (INIS)

    Clark, H.K.

    1980-01-01

    Critical masses and subcritical mass limits in oxide-water mixtures were calculated for actinide nuclides other than /sup 233/U, /sup 235/U, and /sup 239/Pu that have an odd number of neutrons in the nucleus; S/sub n/ transport theory was used together with cross sections, drawn from the GLASS multigroup library, developed to provide accurate forecasts of actinide production at Savannah River

  9. Proposal for experiments with actinide elements

    International Nuclear Information System (INIS)

    Sanchez, R.G.

    1994-01-01

    An analytical study was conducted in which critical masses for some actinide isotopes were calculated with the Monte Carlo Neutron Photon (MCNP) Transport computer code. Different spherical computer models were used for even- and odd-neutron nuclides. Critical masses obtained are tabulated for Np-237, Pu-242, Am-241, Am-243, Pu-241, and Am-242m, together with indirect experimental data. Experimental data are needed for actinides with odd number of neutrons

  10. Interaction between actinides and protein: the calmodulin

    International Nuclear Information System (INIS)

    Brulfert, Florian

    2016-01-01

    Considering the environmental impact of the Fukushima nuclear accident, it is fundamental to study the mechanisms governing the effects of the released radionuclides on the biosphere and thus identify the molecular processes generating the transport and deposition of actinides, such as neptunium and uranium. However, the information about the microscopic aspect of the interaction between actinides and biological molecules (peptides, proteins...) is scarce. The data being mostly reported from a physiological point of view, the structure of the coordination sites remains largely unknown. These microscopic data are indeed essential for the understanding of the interdependency between structural aspect, function and affinity.The Calmodulin (CaM) (abbreviation for Calcium-Modulated protein), also known for its affinity towards actinides, acts as a metabolic regulator of calcium. This protein is a Ca carrier, which is present ubiquitously in the human body, may also bind other metals such as actinides. Thus, in case of a contamination, actinides that bind to CaM could avoid the protein to perform properly and lead to repercussions on a large range of vital functions.The complexation of Np and U was studied by EXAFS spectroscopy which showed that actinides were incorporated in a calcium coordination site. Once the thermodynamical and structural aspects studied, the impact of the coordination site distortion on the biological efficiency was analyzed. In order to evaluate these consequences, a calorimetric method based on enzyme kinetics was developed. This experiment, which was conducted with both uranium (50 - 500 nM) and neptunium (30 - 250 nM) showed a decrease of the heat produced by the enzymatic reaction with an increasing concentration of actinides in the medium. Our findings showed that the Calmodulin actinide complex works as an enzymatic inhibitor. Furthermore, at higher neptunium (250 nM) and uranium (500 nM) concentration the metals seem to have a poison

  11. Positron Spectroscopy of Hydrothermally Grown Actinide Oxides

    Science.gov (United States)

    2014-03-27

    actinide oxides . The work described here is an attempt to characterize the quality of crystals using positron annihilation spectroscopy (PALS). The...Upadhyaya, R. V. Muraleedharan, B. D. Sharma and K. G. Prasad, " Positron lifetime studies on thorium oxide powders," Philosohical Magazine A, vol. 45... crystals . A strong foundation for actinide PALS studies was laid, but further work is required to build a more effective system. Positron Spectroscopy

  12. Separation of actinides and their transmutation

    International Nuclear Information System (INIS)

    Bouchard, M.; Bathelier, M.; Cousin, M.

    1978-08-01

    Neutron irradiation of long-half-life actinides for transmutation into elements with shorter half-life is investigated as a means to reduce the long-term hazards of these actinides. The effectiveness of the method is analysed by applying it to fission product solutions from the first extraction cycle of fuel reprocessing plants. Basic principles, separation techniques and transmutation efficiencies are studied and discussed in detail

  13. The removal of actinide metals from solution

    International Nuclear Information System (INIS)

    Hancock, R.D.; Howell, I.V.

    1980-01-01

    A process is specified for removing actinide metals (e.g. uranium) from solutions. The solution is contacted with a substrate comprising the product obtained by reacting an inorganic solid containing surface hydroxyl groups (e.g. silica gel) with a compound containing a silane grouping, a nitrogen-containing group (e.g. an amine) and other specified radicals. After treatment, the actinide metal is recovered from the substrate. (U.K.)

  14. PREPARATION OF ACTINIDE-ALUMINUM ALLOYS

    Science.gov (United States)

    Moore, R.H.

    1962-09-01

    BS>A process is given for preparing alloys of aluminum with plutonium, uranium, and/or thorium by chlorinating actinide oxide dissolved in molten alkali metal chloride with hydrochloric acid, chlorine, and/or phosgene, adding aluminum metal, and passing air and/or water vapor through the mass. Actinide metal is formed and alloyed with the aluminum. After cooling to solidification, the alloy is separated from the salt. (AEC)

  15. Evaluation of actinide partitioning and transmutation

    International Nuclear Information System (INIS)

    1982-01-01

    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

  16. Rapid determination of actinides in seawater samples

    International Nuclear Information System (INIS)

    Maxwell, S.L.; Culligan, B.K.; Hutchison, J.B.; Utsey, R.C.; McAlister, D.R.

    2014-01-01

    A new rapid method for the determination of actinides in seawater samples has been developed at the Savannah River National Laboratory. The actinides can be measured by alpha spectrometry or inductively-coupled plasma mass spectrometry. The new method employs novel pre-concentration steps to collect the actinide isotopes quickly from 80 L or more of seawater. Actinides are co-precipitated using an iron hydroxide co-precipitation step enhanced with Ti +3 reductant, followed by lanthanum fluoride co-precipitation. Stacked TEVA Resin and TRU Resin cartridges are used to rapidly separate Pu, U, and Np isotopes from seawater samples. TEVA Resin and DGA Resin were used to separate and measure Pu, Am and Cm isotopes in seawater volumes up to 80 L. This robust method is ideal for emergency seawater samples following a radiological incident. It can also be used, however, for the routine analysis of seawater samples for oceanographic studies to enhance efficiency and productivity. In contrast, many current methods to determine actinides in seawater can take 1-2 weeks and provide chemical yields of ∼30-60 %. This new sample preparation method can be performed in 4-8 h with tracer yields of ∼85-95 %. By employing a rapid, robust sample preparation method with high chemical yields, less seawater is needed to achieve lower or comparable detection limits for actinide isotopes with less time and effort. (author)

  17. Domestic Roman architecture in La Alcudia of Elche: the Domus 5-F | La arquitectura doméstica romana en La Alcudia de Elche: la Domus 5-F

    Directory of Open Access Journals (Sweden)

    Julia Sarabia Bautista

    2009-12-01

    Full Text Available One of the most interesting aspects of the process of Romanization at the beginning of the first century in the Iberian Peninsula is domestic architecture, which gradually came to include all the elements that define a Roman domus. In this case we will concentrate on analyzing one of the domestic residences of La Alcudia in Elche, domus 5-F, whose evolution can be clearly seen both in the infrastructure of the house and in its interior decoration. | Uno de los aspectos más interesantes a la hora de estudiar el proceso de romanización sufrido por las sociedades del cambio de era en la Península Ibérica es el de la arquitectura doméstica, a la que de forma paulatina irán incorporándose todos aquellos elementos que definen una domus romana. En este caso nos centraremos en el análisis de uno de los ambientes residenciales de La Alcudia de Elche, la domus 5-F, cuya evolución edilicia estará patente tanto en la propia infraestructura de la casa como en los programas decorativos de su interior.

  18. Recovery of Actinides from Actinide-Aluminium Alloys: Chlorination Route

    International Nuclear Information System (INIS)

    Mendes, E.; Malmbeck, R.; Soucek, P.; Jardin, R.; Glatz, J.P.; Cassayre, L.

    2008-01-01

    A method for recovery of actinides (An) from An-Al alloys formed by electrochemical separation of metallic spent nuclear fuel on solid aluminium electrodes in molten chloride salts is described. The proposed route consists of three main steps: -) vacuum distillation of salt adhered on the electrodes, -) chlorination of An-Al alloy by pure chlorine gas and -) sublimation of formed AlCl 3 . A thermochemical study of the route was performed to determine important chemical reactions and to find optimum experimental conditions for all process steps. Vacuum distillation of the electrode is efficient for complete removal of remaining salt and most fission products, full chlorination of the An-Al alloys is possible at any working temperature and evaporation of AlCl 3 is achieved by heating under argon. Experiments have been carried out using U-Al alloy in order to define parameters providing full alloy chlorination without formation of volatile UCl 5 and UCl 6 . It was shown that full chlorination of An-Al alloys without An losses should be possible at a temperature approx. 150 deg. C. (authors)

  19. Recovery of Actinides from Actinide-Aluminium Alloys: Chlorination Route

    Energy Technology Data Exchange (ETDEWEB)

    Mendes, E.; Malmbeck, R.; Soucek, P.; Jardin, R.; Glatz, J.P. [European Commission, JRC, Institute for Transuranium Elements, Postfach 2340, 76125 Karlsruhe (Germany); Cassayre, L. [Laboratoire de Genie Chimique (LGC), Universite Paul Sabatier, UMR CNRS 5503, 118 route de Narbonne, 31062 Toulouse Cedex 04 (France)

    2008-07-01

    A method for recovery of actinides (An) from An-Al alloys formed by electrochemical separation of metallic spent nuclear fuel on solid aluminium electrodes in molten chloride salts is described. The proposed route consists of three main steps: -) vacuum distillation of salt adhered on the electrodes, -) chlorination of An-Al alloy by pure chlorine gas and -) sublimation of formed AlCl{sub 3}. A thermochemical study of the route was performed to determine important chemical reactions and to find optimum experimental conditions for all process steps. Vacuum distillation of the electrode is efficient for complete removal of remaining salt and most fission products, full chlorination of the An-Al alloys is possible at any working temperature and evaporation of AlCl{sub 3} is achieved by heating under argon. Experiments have been carried out using U-Al alloy in order to define parameters providing full alloy chlorination without formation of volatile UCl{sub 5} and UCl{sub 6}. It was shown that full chlorination of An-Al alloys without An losses should be possible at a temperature approx. 150 deg. C. (authors)

  20. A rational synthesis of a novel imidazo[4,5-f][1,10]phenanthroline templated Schiff base: Characterization, photoluminescence and DFT/TD-DFT study

    Directory of Open Access Journals (Sweden)

    S. Karslıoğlu

    2017-07-01

    Full Text Available A new imidazo[4,5-f][1,10]phenanthroline (imp derivative imidazo-N5,N6-bis((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-ylphenylmethylene-1,10-phenanthroline-5,6-diamine (impap was synthesized in five steps starting from bare phenanthroline (phen precursors. The novel compound was fully characterized by 1H-NMR, IR, elemental analysis and electrospray ionization mass spectroscopy (ESI-MS techniques. Solid state emission spectrum of impap showed two distinct strong emission maxima with large Stokes shifts. The ground state gas phase geometry of impap was predicted by DFT calculations. Excited state properties of the molecule were examined through TD-DFT calculations conducted at the optimized geometry. Responsible transitions for the strong fluorescence of impap were assigned to single component charge transfer transitions with large oscillator strengths based on the ground state calculated molecular orbital contributions.

  1. Dilution effect on the U 5f states in Au matrix: a photoemission spectroscopy study

    Czech Academy of Sciences Publication Activity Database

    Eloirdi, R.; Gouder, T.; Wastin, F.; Huber, F.; Shick, Alexander; Kolorenč, Jindřich

    2011-01-01

    Roč. 84, č. 23 (2011), 235143/1-235143/7 ISSN 1098-0121 R&D Projects: GA ČR(CZ) GAP204/10/0330; GA AV ČR IAA100100912 Institutional research plan: CEZ:AV0Z10100520 Keywords : x-ray photoemission * electronic-structure * photoelectron- spectroscopy * fermion systems Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.691, year: 2011

  2. Data of evolutionary structure change: 1RAAA-3GD5F [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 1RAAA-3GD5F 1RAA 3GD5 A F ANPLYQKHIISINDLSRDDLNLVLATAAKLKANPQPELL...ARGAHILYTDVWTHR---LQLFEQ----YQINAALLNCAAAEAIVLHCLPAHRGEEITDEVMEGPRSRIWDEAENRLHAQK...ex> 1RAA A 1RAAA DML...> A 1RAAA PLPRV--DEIA...dbChain> 1RAAA TEFSGNVPVLN HHHH

  3. Analysis of the Tank 5F Feed and Bleed Residual Solids

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, M.; Diprete, D.: Coleman, C.; Washington, A.

    2011-07-07

    Savannah River Remediation (SRR) is preparing Tank 5F for closure. As part of Tank 5F Closure Mechanical Cleaning, SRR conducted a 'Feed and Bleed' process in Tank 5F. Following this 'Feed and Bleed' Mechanical Cleaning in Tank 5F, SRR collected two tank heel samples (referred to as sample 1 and sample 2) under Riser 5 to determine the composition of the material remaining in the tanks. This document describes sample analysis results. The conclusions from this analysis follow. (1) The anions measured all had a concentration less than 250 mg/kg, except for oxalate, which had a concentration of 2100-2400 mg/kg. (2) The measured cations with the highest concentration were iron (432,000-519,000 mg/kg), nickel (54,600-69,300 mg/kg), and manganese (35,200-42,100 mg/kg). All other cations measured less than 13,000 mg/kg. (3) The radionuclides present in the highest concentration are {sup 90}Sr (3.0 x 10{sup 10} dpm/g), {sup 137}Cs (6.8 x 10{sup 8} dpm/g), and {sup 241}Am (1.4 x 10{sup 8} - 1.8 x 10{sup 8} dpm/g). (4) The particle size analysis shows a large fraction of particles greater than 100 {micro}.

  4. Reactor physics aspects of burning actinides in a nuclear reactor

    International Nuclear Information System (INIS)

    Hage, W.; Schmidt, E.

    1978-01-01

    A short review of the different recycling strategies of actinides other than fuel treated in the literature, is given along with nuclear data requirements for actinide build-up and transmutation studies. The effects of recycling actinides in a nuclear reactor on the flux distribution, the infinite neutron multiplication factor, the reactivity control system, the reactivity coefficients and the delayed neutron fraction are discussed considering a notional LWR or LMFBR as an Actinide Trasmutaton Reactor. Some operational problems of Actinide Transmutation reactors are mentioned, which are caused by the α-decay heat and the neutron sources of Actinide Target Elements

  5. Quantum Chemical Studies of Actinides and Lanthanides: From Small Molecules to Nanoclusters

    Science.gov (United States)

    Vlaisavljevich, Bess

    Research into actinides is of high interest because of their potential applications as an energy source and for the environmental implications therein. Global concern has arisen since the development of the actinide concept in the 1940s led to the industrial scale use of the commercial nuclear energy cycle and nuclear weapons production. Large quantities of waste have been generated from these processes inspiring efforts to address fundamental questions in actinide science. In this regard, the objective of this work is to use theory to provide insight and predictions into actinide chemistry, where experimental work is extremely challenging because of the intrinsic difficulties of the experiments themselves and the safety issues associated with this type of chemistry. This thesis is a collection of theoretical studies of actinide chemistry falling into three categories: quantum chemical and matrix isolation studies of small molecules, the electronic structure of organoactinide systems, and uranyl peroxide nanoclusters and other solid state actinide compounds. The work herein not only spans a wide range of systems size but also investigates a range of chemical problems. Various quantum chemical approaches have been employed. Wave function-based methods have been used to study the electronic structure of actinide containing molecules of small to middle-size. Among these methods, the complete active space self consistent field (CASSCF) approach with corrections from second-order perturbation theory (CASPT2), the generalized active space SCF (GASSCF) approach, and Moller-Plesset second-order perturbation theory (MP2) have been employed. Likewise, density functional theory (DFT) has been used along with analysis tools like bond energy decomposition, bond orders, and Bader's Atoms in Molecules. From these quantum chemical results, comparison with experimentally obtained structures and spectra are made.

  6. Actinide transmutation in nuclear reactors

    International Nuclear Information System (INIS)

    Bultman, J.H.

    1995-01-01

    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)

  7. Actinide transmutation in nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Bultman, J H

    1995-01-17

    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).

  8. Lithium actinide recycle process demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, G.K.; Pierce, R.D.; McPheeters, C.C. [Argonne National Laboratory, IL (United States)

    1995-10-01

    Several pyrochemical processes have been developed in the Chemical Technology Division of Argonne Laboratory for recovery of actinide elements from LWR spent fuel. The lithium process was selected as the reference process from among the options. In this process the LWR oxide spent fuel is reduced by lithium at 650{degrees}C in the presence of molten LiCl. The Li{sub 2}O formed during the reduction process is soluble in the salt. The spent salt and lithium are recycled after the Li{sub 2}O is electrochemically reduced. The oxygen is liberated as CO{sub 2} at a carbon anode or oxygen at an inert anode. The reduced metal components of the LWR spent fuel are separated from the LiCL salt phase and introduced into an electrorefiner. The electrorefining step separates the uranium and transuranium (TRU) elements into two product streams. The uranium product, which comprises about 96% of the LWR spent fuel mass, may be enriched for recycle into the LWR fuel cycle, stored for future use in breeder reactors, or converted to a suitable form for disposal as waste. The TRU product can be recycled as fast reactor fuel or can be alloyed with constituents of the LWR cladding material to produce a stable waste form.

  9. Plutonium oxychalcogenides Pu2O2X (X=O, S, Se, Te) crystal chemistry, magnetic and electrical properties. 5f electrons delocalization

    International Nuclear Information System (INIS)

    Costantini, Jean-Marc.

    1980-05-01

    We have studied the influence of the chalcogen X on the bonding and on the magnetic and electrical properties of the oxychalcogenides Pu 2 O 2 X. These compounds are isostructural with hexagonal La 2 O 3 for X=O, S, Se and with tetragonal La 2 O 2 Te for X=Te. Comparison of Nd 2 O 2 X and Pu 2 O 2 X cell volumes showed that plutonium crystal radius decreases from Pu 2 O 3 through Pu 2 O 2 Te with increasing 5f electrons delocalization and 5f-np overlap. Superexchange interactions through O 2- and X 2- were thought to be responsible for the observed antiferromagnetic ordering. Neel temperatures increase from Pu 2 O 3 through Pu 2 O 2 Te showing that these interactions and subsequent 5f-np covalency are strengthened as chalcogen electronegativity decreases. Hexagonal Pu 2 O 3 is an insulator while the other compounds are semi-conductors with energy gaps around 0.6 eV which were interpreted as the separation between the 6d-7s conduction band and the np valence band. The localized 5f states were located just below the np band, partially overlapping it [fr

  10. Use of fast reactors for actinide transmutation

    International Nuclear Information System (INIS)

    1993-03-01

    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

  11. TUCS/phosphate mineralization of actinides

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. Influence of a Heterocyclic Nitrogen-Donor Group on the Coordination of Trivalent Actinides and Lanthanides by Aminopolycarboxylate Complexants

    Energy Technology Data Exchange (ETDEWEB)

    Grimes, Travis S. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Heathman, Colt R. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Jansone-Popova, Santa [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ivanov, Alexander S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Roy, Santanu [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bryantsev, Vyacheslav S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Zalupski, Peter R. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2018-01-05

    Here, the novel metal chelator N-2-(pyridylmethyl)diethylenetriamine-N,N',N",N"-tetraacetic acid (DTTA-PyM) was designed to replace a single oxygen-donor acetate group of the well-known aminopolycarboxylate complexant diethylenetriamine-N,N,N',N",N"-pentaacetic acid (DTPA) with a nitrogen-donor 2-pyridylmethyl. Potentiometric, spectroscopic, computational, and radioisotope distribution methods show distinct differences for the 4f and 5f coordination environments and enhanced actinide binding due to the nitrogen-bearing heterocyclic moiety. The Am3+, Cm3+, and Ln3+ complexation studies for DTTA-PyM reveal an enhanced preference, relative to DTPA, for trivalent actinide binding. Fluorescence studies indicate no changes to the octadentate coordination of trivalent curium, while evidence of heptadentate complexation of trivalent europium is found in mixtures containing EuHL(aq) complexes at the same aqueous acidity. The denticity change observed for Eu3+ suggests that complex protonation occurs on the pyridyl nitrogen. Formation of the CmHL(aq) complex is likely due to the protonation of an available carboxylate group because the carbonyl oxygen can maintain octadentate coordination through a rotation. The observed suppressed protonation of the pyridyl nitrogen in the curium complexes may be attributed to stronger trivalent actinide binding by DTTA-PyM. Density functional theory calculations indicate that added stabilization of the actinide complexes with DTTA-PyM may originate from π-back-bonding interactions between singly occupied 5f orbitals of Am3+ and the pyridyl nitrogen. The differences between the stabilities of trivalent actinide chelates (Am3+, Cm3+) and trivalent lanthanide chelates (La3+–Lu3+) are observed in liquid–liquid extraction systems, yielding unprecedented 4f/5f differentiation when using DTTA

  13. Strategies for minority actinides transmutation in fast reactors

    International Nuclear Information System (INIS)

    Perez-Martin, S.; Martin-Fuertes, F.; Alvarez-Velarde, F.

    2010-01-01

    Presentation of the strategies that can be followed in fast reactors designed for the fourth generation to reduce the inventory of minority actinides generated in current light water reactors, as the actinides generation in fast reactor.

  14. Final Project Report for ER15351 ''A Study of New Actinide Zintl Ions Materials''

    International Nuclear Information System (INIS)

    Peter K. Dorhout

    2007-01-01

    The structural chemistry of actinide main-group metal materials provides the fundamental basis for the understanding of structural coordination chemistry and the formation of materials with desired or predicted structural features. The main-group metal building blocks, comprising sulfur-group, phosphorus-group, or silicon-group elements, have shown versatility in oxidation state, coordination, and bonding preferences. These building blocks have allowed us to elucidate a series of structures that are unique to the actinide elements, although we can find structural relationships to transition metal and 4f-element materials. In the past year, we investigated controlled metathesis and self-propagating reactions between actinide metal halides and alkali metal salts of main-group metal chalcogenides such as K-P-S salts. Ternary plutonium thiophosphates have resulted from these reactions at low temperature in sealed ampules. we have also focused efforts to examine reactions of Th, U, and Pu halide salts with other alkali metal salts such as Na-Ge-S and Na-Si-Se and copper chloride to identify if self-propagating reactions may be used as a viable reaction to prepare new actinide materials and we prepared a series of U and Th copper chalcogenide materials. Magnetic measurements continued to be a focus of actinide materials prepared in our laboratory. We also contributed to the XANES work at Los Alamos by preparing materials for study and for comparison with environmental samples

  15. Application of multi-step excitation schemes for detection of actinides and lanthanides in solutions by luminescence/chemiluminescence laser spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Izosimov, I. [Joint Institute for Nuclear Research, Joliot Curie 6, Dubna 141980 (Russian Federation)

    2016-07-01

    The use of laser radiation with tunable wavelength allows the selective excitation of actinide/lanthanide species with subsequent registration of luminescence/chemiluminescence for their detection. This work is devoted to applications of the time-resolved laser-induced luminescence spectroscopy and time-resolved laser-induced chemiluminescence spectroscopy for the detection of lanthanides and actinides. Results of the experiments on U, Eu, and Sm detection by TRLIF (Time Resolved Laser Induced Fluorescence) method in blood plasma and urine are presented. Data on luminol chemiluminescence in solutions containing Sm(III), U(IV), and Pu(IV) are analyzed. It is shown that appropriate selectivity of lanthanide/actinide detection can be reached when chemiluminescence is initiated by transitions within 4f- or 5f-electron shell of lanthanide/actinide ions corresponding to the visible spectral range. In this case chemiluminescence of chemiluminogen (luminol) arises when the ion of f element is excited by multi-quantum absorption of visible light. The multi-photon scheme of chemiluminescence excitation makes chemiluminescence not only a highly sensitive but also a highly selective tool for the detection of lanthanide/actinide species in solutions. (author)

  16. Ultratrace analysis of transuranic actinides by laser-induced fluorescence

    Science.gov (United States)

    Miller, S.M.

    1983-10-31

    Ultratrace quantities of transuranic actinides are detected indirectly by their effect on the fluorescent emissions of a preselected fluorescent species. Transuranic actinides in a sample are coprecipitated with a host lattice material containing at least one preselected fluorescent species. The actinide either quenches or enhances the laser-induced fluorescence of the preselected fluorescent species. The degree of enhancement or quenching is quantitatively related to the concentration of actinide in the sample.

  17. Special actinide nuclides: Fuel or waste?

    International Nuclear Information System (INIS)

    Srinivasan, M.; Rao, K.S.; Dingankar, M.V.

    1989-01-01

    The special actinide nuclides such as Np, Cm, etc. which are produced as byproducts during the operation of fission reactors are presently looked upon as 'nuclear waste' and are proposed to be disposed of as part of high level waste in deep geological repositories. The potential hazard posed to future generations over periods of thousands of years by these long lived nuclides has been a persistent source of concern to critics of nuclear power. However, the authors have recently shown that each and every one of the special actinide nuclides is a better nuclear fuel than the isotopes of plutonium. This finding suggests that one does not have to resort to exotic neutron sources for transmuting/incinerating them as proposed by some researchers. Recovery of the special actinide elements from the waste stream and recycling them back into conventional fission reactors would eliminate one of the stigmas attached to nuclear energy

  18. Interaction of actinides with natural microporous materials

    International Nuclear Information System (INIS)

    Misaelides, P.; Godelirsas, A.

    1998-01-01

    The existing studies mainly concern the sorption of thorium, uranium, neptunium, plutonium and americium from aqueous media by clay minerals and zeolites as well as the determination of the corresponding chemical processes taking place at the mineral-water interface. The investigation techniques applied for this purpose include, except the conventional wet-chemical and radiochemical methods, advanced spectroscopic methods such as extended X-ray absorption fine structure spectroscopy (EXAFS), Rutherford Backscattered Spectroscopy (RBS), X-ray photoelectron spectroscopy (XPS) and Raman Spectroscopy. These techniques significantly contribute to the characterization of the reacted mineral waters and to the explanation of the structural and compositional characteristics of the sorbed actinide species. Theoretical models regarding the aqueous chemistry and speciation of the actinides have also been developed aiming the elucidation of the complex actinide sorption mechanisms. This contribution will critically review of the existing literature, present recently obtained unpublished results and discuss the necessity of future work in the field. (authors)

  19. Monazite as a suitable actinide waste form

    Energy Technology Data Exchange (ETDEWEB)

    Schlenz, Hartmut; Heuser, Julia; Schmitz, Stephan; Bosbach, Dirk [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Energie und Klimaforschung (IEK), Nukleare Entsorgung und Reaktorsicherheit (IEK-6); Neumann, Andreas [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Energie und Klimaforschung (IEK), Nukleare Entsorgung und Reaktorsicherheit (IEK-6); RWTH Aachen Univ. (Germany). Inst. for Crystallography

    2013-03-01

    The conditioning of radioactive waste from nuclear power plants and in some countries even of weapons plutonium is an important issue for science and society. Therefore the research on appropriate matrices for the immobilization of fission products and actinides is of great interest. Beyond the widely used borosilicate glasses, ceramics are promising materials for the conditioning of actinides like U, Np, Pu, Am, and Cm. Monazite-type ceramics with general composition LnPO{sub 4} (Ln = La to Gd) and solid solutions of monazite with cheralite or huttonite represent important materials in this field. Monazite appears to be a promising candidate material, especially because of its outstanding properties regarding radiation resistance and chemical durability. This article summarizes the most recent results concerning the characterization of monazite and respective solid solutions and the study of their chemical, thermal, physical and structural properties. The aim is to demonstrate the suitability of monazite as a secure and reliable waste form for actinides. (orig.)

  20. Actinide separations by supported liquid membranes

    International Nuclear Information System (INIS)

    Danesi, P.R.; Horwitz, E.P.; Rickert, P.; Chiarizia, R.

    1984-01-01

    The work has demonstrated that actinide removal from synthetic waste solutions using both flat-sheet and hollow-fiber SLM's is a feasible chemical process at the laboratory scale level. The process is characterized by the typical features of SLM's processes: very small quantities of extractant required; the potential for operations with high feed/strip volume ratios, resulting in a corresponding concentration factor of the actinides; and simplicity of operation. Major obstacles to the implementation of the SLM technology to the decontamination of liquid nuclear wastes are the probable low resistance of polypropylene supports to high radiation fields, which may prevent the application to high-level nuclear wastes; the unknown lifetime of the SLM; and the high Na content of the separated actinide solution

  1. Localized 5f electrons in superconducting PuCoIn5: consequences for superconductivity in PuCoGa5

    International Nuclear Information System (INIS)

    Bauer, E D; Altarawneh, M M; Tobash, P H; Gofryk, K; Ayala-Valenzuela, O E; Mitchell, J N; McDonald, R D; Mielke, C H; Ronning, F; Scott, B L; Thompson, J D; Griveau, J-C; Colineau, E; Eloirdi, R; Caciuffo, R; Janka, O; Kauzlarich, S M

    2012-01-01

    The physical properties of the first In analog of the PuMGa 5 (M = Co, Rh) family of superconductors, PuCoIn 5 , are reported. With its unit cell volume being 28% larger than that of PuCoGa 5 , the characteristic spin-fluctuation energy scale of PuCoIn 5 is three to four times smaller than that of PuCoGa 5 , which suggests that the Pu 5f electrons are in a more localized state relative to PuCoGa 5 . This raises the possibility that the high superconducting transition temperature T c = 18.5 K of PuCoGa 5 stems from the proximity to a valence instability, while the superconductivity at T c = 2.5 K of PuCoIn 5 is mediated by antiferromagnetic spin fluctuations associated with a quantum critical point. (fast track communication)

  2. Minor Actinide Separations Using Ion Exchangers Or Ionic Liquids

    International Nuclear Information System (INIS)

    Hobbs, D.; Visser, A.; Bridges, N.

    2011-01-01

    This project seeks to determine if (1) inorganic-based ion exchange materials or (2) electrochemical methods in ionic liquids can be exploited to provide effective Am and Cm separations. Specifically, we seek to understand the fundamental structural and chemical factors responsible for the selectivity of inorganic-based ion-exchange materials for actinide and lanthanide ions. Furthermore, we seek to determine whether ionic liquids can serve as the electrolyte that would enable formation of higher oxidation states of Am and other actinides. Experiments indicated that pH, presence of complexants and Am oxidation state exhibit significant influence on the uptake of actinides and lanthanides by layered sodium titanate and hybrid zirconium and tin phosphonate ion exchangers. The affinity of the ion exchangers increased with increasing pH. Greater selectivity among Ln(III) ions with sodium titanate materials occurs at a pH close to the isoelectric potential of the ion exchanger. The addition of DTPA decreased uptake of Am and Ln, whereas the addition of TPEN generally increases uptake of Am and Ln ions by sodium titanate. Testing confirmed two different methods for producing Am(IV) by oxidation of Am(III) in ionic liquids (ILs). Experimental results suggest that the unique coordination environment of ionic liquids inhibits the direct electrochemical oxidation of Am(III). The non-coordinating environment increases the oxidation potential to a higher value, while making it difficult to remove the inner coordination of water. Both confirmed cases of Am(IV) were from the in-situ formation of strong chemical oxidizers.

  3. Bond lengths and bond strengths in compounds of the 5f elements

    International Nuclear Information System (INIS)

    Zachariasen, W.H.

    1975-01-01

    The variation of bond length (D) with bond strength (S) in normal valence compounds of 3d, 4d, 5d-4f, and 6d-5f elements can be represented approximately as D(S)=D(0.5) F(S), where D(0.5) is a characteristic constant for a given bond and F(S) an empirical function which is the same for all bonds. A bond strength Ssub(ij)=ssub(ji) is assigned to the bond between atoms i and j such that Σsub(j) Ssub(ij)=vsub(i) and Σsub(i) Ssub(ij)=vsub(j), where vsub(i) and vsub(j) are the normal valences of the two atoms. The function F(S) decreases monotonically with increasing S, and is normalized to unity at S=0.5, so that the constant D(0.5) has the physical meaning of being the bond length adjusted to S=0.5. The method described above was used to interpret and systematize the experimental results on bond lengths in oxides, halides, and oxyhalides of the 5f elements. (U.S.)

  4. US/UK actinides experiment at the Dounreay PFR. I. Fission products

    International Nuclear Information System (INIS)

    Raman, S.; Murphy, B.D.

    1995-01-01

    The United States and the United Kingdom have been engaged in a joint research program in which samples of higher actinides were irradiated in the 600-MW Dounreay Prototype Fast Reactor in Scotland. Analytical results using mass spectrometry and radiometry for actinides and fission products are now available for the samples in Fuel Pins 1 and 2 which were irradiated for 63 full-power days and for the samples in Fuel Pin 4 which were irradiated for 492 full-power days. Results from these three fuel pins are providing estimates of integral cross sections and fission yields. (authors)

  5. Rate Constants for Reactions of Radiation-Produced Transients in Aqueous Solutions of Actinides

    International Nuclear Information System (INIS)

    Gordon, S.; Sullivan, J.C.; Ross, A.B.

    1986-01-01

    Rate constants have been critically compiled for reactions of ions of the actinides Am, Cf, Cm, Np, Pu, Th, and U, as well as the element Tc, in different oxidation states with various chemical species in aqueous solution. The reactants include products of the radiolysis of water (hydrated electrons, hydrogen atoms, hydroxyl radicals, hydrogen peroxide) and transient species derived from other solutes (e.g., carbonate radical). The data are useful in the estimation of migration properties of actinides, which are relevant to waste management studies

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

    International Nuclear Information System (INIS)

    Choppin, G.R.

    1981-01-01

    Visible spectroscopy, NMR ( 1 H 1 , 6 C 13 , 57 La 139 ) 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

  7. Mechanisms for the reduction of actinide ions by Geobacter sulfurreducens

    International Nuclear Information System (INIS)

    Renshaw, J.C.; Livens, F.R.; May, I.; Lloyd, J.R.

    2005-01-01

    Full text of publication follows: Three of the most problematic radioactive contaminants are the actinide elements uranium, neptunium and plutonium. All three pose considerable long-term environmental risks. The most stable environmental oxidation states of uranium and neptunium are VI and V, respectively, as the di-oxo cations [UO 2 ] 2+ and [NpO 2 ] + ; both are highly soluble and so are relatively mobile and biologically available in the environment. In similar conditions, plutonium mainly exists as Pu(IV), which forms a highly insoluble hydrous oxide, although is also environmentally stable in the more soluble III, V and VI oxidation states. The bio-reduction of U(VI) by anaerobic subsurface microorganisms has been the focus of much recent interest. Both Fe(III)- and sulfate-reducing bacteria have been shown to reduce soluble [U VI O 2 ] 2+ to insoluble U IV O 2 , with c-type cytochromes involved in electron transfer to the actinide. Such transformations offer a strategy for the bio-remediation of uranium contaminated groundwater and a potential mechanism for the bio-deposition of uranium ores. The mechanism of U(VI). reduction has important implications for the potential microbial reduction of transuranic elements with environmentally stable lower oxidation states. Reduction of mobile 237 Np(V) to Np(IV) and subsequent precipitation may be advantageous whilst remobilization of immobile Pu(IV) as more soluble Pu(III) species could have important environmental implications. Conversely, selective reduction might allow targeting of particular radionuclide species. The model anaerobic bacterium Geobacter sulfurreducens is typical of those found in contaminated subsurface environments and has been shown to reduce soluble [U VI O 2 ] 2+ to insoluble U IV O 2 . In the course of this study we use X-ray absorption spectroscopy (XAS) to show that G. sulfurreducens reduces U(VI) by a one-electron reduction, forming an unstable [UO 2 ] + species which subsequently

  8. Photoemission study of 5f localization in UPd/sub 3-x/(Pt,Rh)/sub x/

    International Nuclear Information System (INIS)

    Arko, A.J.; Koelling, D.D.; Dunlap, B.D.; Mitchell, A.W.

    1987-10-01

    Photoemission measurements in the two systems UPd/sub 3-x/(Pt,Rh)/sub x/ show that the 5f spectra are consistent with localized 5f electrons (peak in spectral weight is below E/sub F/ for all x within the double hexagonal DO 24 phase) while at both phase transitions the 5f peaks lock in at E/sub F/ consistent with intinerancy. A satellite 5f peak representative of d-screening is observed in both localized and itinerant systems. 17 refs., 3 figs

  9. Sequential analysis of selected actinides in urine

    International Nuclear Information System (INIS)

    Kramer, G.H.

    1980-07-01

    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)

  10. Aqueous actinide complexes: A thermochemical assessment

    International Nuclear Information System (INIS)

    Fuger, J.; Khodakovsky, I.L.; Medvedev, V.A.; Navratil, J.D.

    1979-01-01

    The scope and purpose of an assessment of the thermodynamic properties of the aqueous actinide complexes are presented. This work which, at present, is limited to inorganic ligands and three selected organic ligands (formate, acetate and oxalate), is part of an effort established by the International Atomic Energy Agency to assess the thermodynamic properties of the actinides and their compounds. The problems involved in this work are illustrated by discussing the present status of the assessment as related to a few complex species, (hydroxyl-, fluoride-, carbonate complexes). (orig.) [de

  11. Actinide elements in aquatic and terrestrial environments

    International Nuclear Information System (INIS)

    Bondietti, E.A.; Bogle, M.A.; Brantley, J.N.

    1979-01-01

    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 239 Np 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

  12. Hydrothermal processing of actinide contaminated organic wastes

    International Nuclear Information System (INIS)

    Worl, A.; Buelow, S.J.; Le, L.A.; Padilla, D.D.; Roberts, J.H.

    1997-01-01

    Hydrothermal oxidation is an innovative process for the destruction of organic wastes, that occurs above the critical temperature and pressure of water. The process provides high destruction and removal efficiencies for a wide variety of organic and hazardous substances. For aqueous/organic mixtures, organic materials, and pure organic liquids hydrothermal processing removes most of the organic and nitrate components (>99.999%) and facilitates the collection and separation of the actinides. We have designed, built and tested a hydrothermal processing unit for the removal of the organic and hazardous substances from actinide contaminated liquids and solids. Here we present results for the organic generated at the Los Alamos National Laboratory Plutonium Facility

  13. Actinide phosphonate complexes in aqueous solutions

    International Nuclear Information System (INIS)

    Nash, K.L.

    1993-01-01

    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 (-PO 3 H 2 ) 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

  14. Molecular dynamics studies of actinide nitrides

    International Nuclear Information System (INIS)

    Kurosaki, Ken; Uno, Masayoshi; Yamanaka, Shinsuke; Minato, Kazuo

    2004-01-01

    The molecular dynamics (MD) calculation was performed for actinide nitrides (UN, NpN, and PuN) in the temperature range from 300 to 2800 K to evaluate the physical properties viz., the lattice parameter, thermal expansion coefficient, compressibility, and heat capacity. The Morse-type potential function added to the Busing-Ida type potential was employed for the ionic interactions. The interatomic potential parameters were determined by fitting to the experimental data of the lattice parameter. The usefulness and applicability of the MD method to evaluate the physical properties of actinide nitrides were studied. (author)

  15. Static and dynamic deformations of actinide nuclei

    International Nuclear Information System (INIS)

    Rozmej, P.

    1985-09-01

    The zero-point quadrupole-hexadecapole vibrations have been taken into account to calculate dynamical deformations for even-even actinide nuclei. The collective and intrinsic motions are separated according to the Born-Oppenheimer approximation. The collective Hamiltonian is constructed using the macroscopic-microscopic method in the potential energy part and the cranking model in the kinetic energy part. The BCS theory with a modified oscillator potential is applied to describe the intrinsic motion of nucleons. A new set of Nilsson potential parameters, which produces a much better description of the properties of light actinide nuclei, has also been found. (orig.)

  16. Sol-gel chemistry applied to the synthesis of polymetallic oxides including actinides reactivity and structure from solution to solid state; Synthese par voie douce d'oxydes polymetalliques incluant des actinides: reactivite et structure de la solution au solide

    Energy Technology Data Exchange (ETDEWEB)

    Lemonnier, St

    2006-02-15

    Minor actinides transmutation is studied at present in order to reduce the radiotoxicity of nuclear waste and the assessment of its technical feasibility requires specific designed materials. When considering americium, yttria stabilized zirconia (Am{sup III} YII Zriv)Or{sub x} is among the ceramic phases that one which presents the required physico-chemical properties. An innovative synthesis of this mixed oxide by sol-gel process is reported in this manuscript. The main aim of this work is to adjust the reactivity of the different metallic cations in aqueous media using complexing agent, in order to initiate a favourable interaction for a homogeneous elements repartition in the forming solid phase. The originality of the settled synthesis lies on an in-situ formation of a stable and monodisperse nano-particles dispersion in the presence of acetylacetone. The main reaction mechanisms have been identified: the sol stabilisation results from an original interaction between the three compounds (Zrly, trivalent cations and acetylacetone). The sol corresponds to a structured system at the nanometer scale for which zirconium and trivalent cations are homogeneously dispersed, preliminary to the sol-gel transition. Furthermore, preliminary studies were carried out with a view to developing materials. They have demonstrated that numerous innovative and potential applications can be developed by taking advantage of the direct and controlled formation of the sol and by adapting the sol-gel transition. The most illustrating result is the preparation of a sintered pellet with the composition Am0,13Zro,73Yo,0901,89 using this approach. (author)

  17. Transmutation of waste actinides in light water reactors

    International Nuclear Information System (INIS)

    Gorrell, T.C.

    1979-04-01

    Actinide recycle and transmutation calculations were made for three irradiation options of a light water reactor (LWR). The cases considered were: all actinides recycled in regular uranium fuel assemblies; transuranic actinides recycled in separate MOX assemblies with 235 U enrichment of uranium; and transuranic actinides recycled in separate MOX assemblies with plutonium enrichment of natural uranium. When all actinides were recycled in a uniform lattice, the transuranic inventory after ten recycles was 38% of the inventory accumulated without recycle. When the transuranics from two regular uranium assemblies were combined with those recycled from a MOX assembly, the transuranic inventory was reduced 50% after five recycles

  18. Chemical compatibility of HLW borosilicate glasses with actinides

    International Nuclear Information System (INIS)

    Walker, C.T.; Scheffler, K.; Riege, U.

    1978-11-01

    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 23 0 C and 115 0 C. (orig.) [de

  19. Actinide recycle in LMFBRs as a waste management alternative

    International Nuclear Information System (INIS)

    Beaman, S.L.

    1979-01-01

    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

  20. Transmutation of LWR waste actinides in thermal reactors

    International Nuclear Information System (INIS)

    Gorrell, T.C.

    1979-01-01

    Recycle of actinides to a reactor for transmutation to fission products is being considered as a possible means of waste disposal. Actinide transmutation calculations were made for two irradiation options in a thermal (LWR) reactor. The cases considered were: all actinides recycled in regular uranium fuel assemblies, and transuranic actinides recycled in separate mixed oxide (MOX) assemblies. When all actinides were recycled in a uranium lattice, a reduction of 62% in the transuranic inventory was achieved after 10 recycles, compared to the inventory accumulated without recycle. When the transuranics from 2 regular uranium assemblies were combined with those recycled from a MOX assembly, the transuranic inventory was reduced 50% after 5 recycles

  1. Actinide Solubility and Speciation in the WIPP [PowerPoint

    Energy Technology Data Exchange (ETDEWEB)

    Reed, Donald T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-02

    The presentation begins with the role and need for nuclear repositories (overall concept, international updates (Sweden, Finland, France, China), US approach and current status), then moves on to the WIPP TRU repository concept (design, current status--safety incidents of February 5 and 14, 2014, path forward), and finally considers the WIPP safety case: dissolved actinide concentrations (overall approach, oxidation state distribution and redox control, solubility of actinides, colloidal contribution and microbial effects). The following conclusions are set forth: (1) International programs are moving forward, but at a very slow and somewhat sporadic pace. (2) In the United States, the Salt repository concept, from the perspective of the long-term safety case, remains a viable option for nuclear waste management despite the current operational issues/concerns. (3) Current model/PA prediction (WIPP example) are built on redundant conservatisms. These conservatisms are being addressed in the ongoing and future research to fill existing data gaps--redox control of plutonium by Fe(0, II), thorium (analog) solubility studies in simulated brine, contribution of intrinsic and biocolloids to the mobile concentration, and clarification of microbial ecology and effects.

  2. Actinide Solubility and Speciation in the WIPP [PowerPoint

    International Nuclear Information System (INIS)

    Reed, Donald T.

    2015-01-01

    The presentation begins with the role and need for nuclear repositories (overall concept, international updates (Sweden, Finland, France, China), US approach and current status), then moves on to the WIPP TRU repository concept (design, current status--safety incidents of February 5 and 14, 2014, path forward), and finally considers the WIPP safety case: dissolved actinide concentrations (overall approach, oxidation state distribution and redox control, solubility of actinides, colloidal contribution and microbial effects). The following conclusions are set forth: (1) International programs are moving forward, but at a very slow and somewhat sporadic pace. (2) In the United States, the Salt repository concept, from the perspective of the long-term safety case, remains a viable option for nuclear waste management despite the current operational issues/concerns. (3) Current model/PA prediction (WIPP example) are built on redundant conservatisms. These conservatisms are being addressed in the ongoing and future research to fill existing data gaps--redox control of plutonium by Fe(0, II), thorium (analog) solubility studies in simulated brine, contribution of intrinsic and biocolloids to the mobile concentration, and clarification of microbial ecology and effects.

  3. Contribution to the study of fluoride and oxyfluoride elements 4d, 5d and 5f by thermochromatography

    International Nuclear Information System (INIS)

    Fargeas, M.

    1986-01-01

    The results exposed in this report constitute an extension of works effected in laboratory of Radiochemistry, on the thermochromatography. They confirm the validity of this method as way to identify oxidation states of element. In a first time experimental results realised in fluorined atmosphere on Tc, Re, Os, Mo and Ir by thermochromatography, have enable to extend the identification scope right to seven valency. This results applied to actinides and especially to neptunium and plutonium have given rise to identification for the first time, in gas phase, the next compounds: PuO 2 F 3 , PuOF 5 , NpO 3 F, NpO 2 F 3 , NpOF 5 , NpF 7 and the confirmation to PuO 3 F. Moreover the adsorption heat of UF 4 , UF 6 and IrOF 4 has been determined. The adsorbent surface has been studied by Electron Spectroscopy for Chemical Analysis (E.S.C.A.), it is an homogeneous layer of NiF 2 along the thermochromatograph. The valency 6 of the molybdene has been confirmed on the compound identified by thermochromatography as MoOF 4 . The theoretical model of adsorption founded on a chimisorption process between one fluorined or oxyfluorined Ru molecules and one then two NiF 2 molecules, allow to make out lineares correlations between the complex adsorbent-adsorbat energezing gain of formation and the characteristic deposition temperature, significant of the compound and the element valency [fr

  4. Heterogeneous all actinide recycling in LWR all actinide cycle closure concept

    International Nuclear Information System (INIS)

    Tondinelli, Luciano

    1980-01-01

    A project for the elimination of transuranium elements (Waste Actinides, WA) by neutron transmutation is developed in a commercial BWR with U-Pu (Fuel Actinides, FA) recycle. The project is based on the All Actinide Cycle Closure concept: 1) closure of the 'back end' of the fuel cycle, U-Pu coprocessing, 2) waste actinide disposal by neutron transmutation. The reactor core consists of Pu-island fuel assemblies containing WAs in target pins. Two parallel reprocessing lines for FAs and WAs are provided. Mass balance, hazard measure, spontaneous activity during 10 recycles are calculated. Conclusions are: the reduction in All Actinide inventory achieved by Heterogeneous All Actinide Recycling is on the order of 83% after 10 recycles. The U235 enrichment needed for a constant end of cycle reactivity decreases for increasing number of recycles after the 4th recycle. A diffusion-burnup calculation of the pin power peak factors in the fuel assembly shows that design limits can be satisfied. A strong effort should be devoted to the solution of the problems related to high values of spontaneous emission by the target pins

  5. Calculated investigation of actinide transmutation in the BOR-60 reactor

    International Nuclear Information System (INIS)

    Zhemkov, I.Yu.; Ishunina, O.V.; Yakovleva, I.V.

    2000-01-01

    One of the prospective actinide burner reactor type is the fast reactor with a 'hard' spectrum and small breeding factor, which is the BOR-60. The calculated investigations demonstrate that Loading up to 40% of minor-actinides to the BOR-60 reactor did not lead to the considerable change of neutron-physical characteristics. The performed calculations show that the BOR- 60 reactor possesses a high efficiency of the minor-actinide and plutonium bum-up (up to 37 kg/(TW · h)) hat is comparable with properties of the actinide burner-reactors under design. The BOR-60 reactor can provide a homogeneous minor-actinide Loading (minor-actinide addition to the standard fuel) to the core and heterogeneous Loading (as separate assemblies-targets with a high minor-actinide fraction) to the first rows of a radial blanket that allows the optimum usage of the reactor and its characteristics. (authors)

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

    International Nuclear Information System (INIS)

    Lemmel, H.D.

    1986-05-01

    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

  7. Trends in actinide processing at Hanford

    International Nuclear Information System (INIS)

    Harmon, H.D.

    1993-09-01

    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

  8. Report of the panel on inhaled actinides

    International Nuclear Information System (INIS)

    Anon.

    1978-01-01

    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

  9. Actinide and fission product partitioning and transmutation

    Energy Technology Data Exchange (ETDEWEB)

    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.)

  10. Placental transfer of plutonium and other actinides

    International Nuclear Information System (INIS)

    Griessl, I.; Stieve, F.E.

    1988-10-01

    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) [de

  11. Supercritical fluid carbon dioxide extraction of actinides

    International Nuclear Information System (INIS)

    Rao, Ankita; Tomar, B.S.

    2016-01-01

    Supercritical fluid extraction (SFE) is a process akin to liquid-liquid or solvent extraction where a Supercritical fluid (SCF) is contacted with a solid/ liquid matrix for the purpose of separating the component of interest from the original matrix. Carbon dioxide is a preferred choice as supercritical fluid (SCF) owing to its moderate critical parameter (P c = 7.38 MPa and T c = 304.1K) coupled with radiation and chemical stability, non toxic nature and low cost. Despite widespread applications for extraction of organic compounds and associated advantages especially liquid waste minimization, the SFE of metal ions was left unexplored for quite some time, as direct metal ion extraction is inefficient due charge neutralization requirement and weak solute-solvent interaction. Neutral SCF soluble metal-ligand complexation is imperative and SFE of actinides was reported only in 1994. Several studies have been carried out on SFE of uranium, thorium and plutonium from nitric acid medium employing different sets of ligands (organophosphorus, diketones, amides). Especially attractive is the possibility of direct dissolution and extraction of actinides employing ligand-acid adducts (like TBP.HNO 3 adduct) from solid matrices of different stages of nuclear fuel cycle viz. ores, spent nuclear fuels and radioactive wastes. Also, partitioning of actinides from fission products has been explored in spent nuclear fuel. These studies on supercritical fluid extraction of actinides indicate a more efficient and environmentally sustainable technology. (author)

  12. ACTINET: a European Network for Actinide Sciences

    International Nuclear Information System (INIS)

    Bernard Boullis; Pascal Chaix

    2006-01-01

    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

  13. Characterization of actinide physics specimens for the US/UK joint experiment in the Dounreay Prototype Fast Reactor

    International Nuclear Information System (INIS)

    Walker, R.L.; Botts, J.L.; Cooper, J.H.; Adair, H.L.; Bigelow, J.E.; Raman, S.

    1983-10-01

    The United States and the United Kingdom are engaged in a joint research program in which samples of the higher actinides are irradiated in the Dounreay Prototype Fast Reactor in Scotland. The purpose of the porogram is (1) to study the materials behavior of selected higher actinide fuels and (2) to determine the integral cross sections of a wide variety of the higher actinide isotopes. Samples of the actinides are incorporated in fuel pins inserted in the core. For the fuel study, the actinides selected are 241 Am and 244 Cm in the form of Am 2 O 3 , Cm 2 O 3 , and Am 6 Cm(RE) 7 O 21 , where (RE) represents a mixture of lanthanides. For the cross-section determinations, the samples are milligram quantities of actinide oxides of 248 Cm, 246 Cm, 244 Cm, 243 Cm, 243 Am, 241 Am, 244 Pu, 242 Pu, 241 Pu, 240 Pu, 239 Pu, 238 Pu, 237 Np, 238 U, 236 U, 235 U, 234 U, 233 U, 232 Th, 230 Th, and 231 Pa encapsulated in vanadium. Coincident with the irradiations, neutron flux and energy spectral measurements are made with vanadium-encapsulated dosimeter materials located within the same fuel pins

  14. Actinide and Fission Product Partitioning and Transmutation

    International Nuclear Information System (INIS)

    2015-06-01

    The benefits of partitioning and transmutation (P and T) have now been established worldwide and, as a result, many countries are pursuing R and D programmes to advance the technologies associated with P and T. In this context, the OECD Nuclear Energy Agency (NEA) has organised a series of biennial information exchange meetings to provide experts with a forum to present and discuss state-of-the-art developments in the field of partitioning and transmutation since 1990. The OECD Nuclear Energy Agency Information Exchange Meeting on Actinides and Fission Products Partitioning and Transmutation is a forum for experts to present and discuss the state-of-the-art development in the field of P and T. Thirteen meetings have been organised so far and held in Japan, the United States, France, Belgium, Spain, the Republic of Korea and the Czech Republic. This 13. meeting was hosted by Seoul National University (Seoul, Republic of Korea) and was organised in co-operation with the International Atomic Energy Agency (IAEA) and the European Community (EC). The meeting covered strategic and scientific developments in the field of P and T such as: fuel cycle strategies and transition scenarios, the role of P and T in the potential evolution of nuclear energy as part of the future energy mix; radioactive waste management strategies; transmutation fuels and targets; advances in pyro and aqueous separation processes; P and T specific technology requirements (materials, spallation targets, coolants, etc.); transmutation systems: design, performance and safety; impact of P and T on the fuel cycle; fabrication, handling and transportation of transmutation fuels. A total of 103 presentations (39 oral and 64 posters) were discussed among the 110 participants from 19 countries and 2 international organisations. The meeting consisted of one plenary session where national and international programmes were presented followed by 5 technical sessions: - Fuel Cycle Strategies and Transition

  15. European Europart integrated project on actinide partitioning

    International Nuclear Information System (INIS)

    Madic, C.; Hudson, M.J.

    2005-01-01

    This poster presents the objectives of EUROPART, a scientific integrated project between 24 European partners, mostly funded by the European Community within the FP6. EUROPART aims at developing chemical partitioning processes for the so-called minor actinides (MA) contained in nuclear wastes, i.e. from Am to Cf. In the case of dedicated spent fuels or targets, the actinides to be separated also include U, Pu and Np. The techniques considered for the separation of these radionuclides belong to the fields of hydrometallurgy and pyrometallurgy, as in the previous FP5 programs named PARTNEW and PYROREP. The two main axes of research within EUROPART will be: The partitioning of MA (from Am to Cf) from high burn-up UO x fuels and multi-recycled MOx fuels; the partitioning of the whole actinide family for recycling, as an option for advanced dedicated fuel cycles (and in connection with the studies to be performed in the EUROTRANS integrated project). In hydrometallurgy, the research is organised into five Work Packages (WP). Four WP are dedicated to the study of partitioning methods mainly based on the use of solvent extraction methods, one WP is dedicated to the development of actinide co-conversion methods for fuel or target preparation. The research in pyrometallurgy is organized into four WP, listed hereafter: development of actinide partitioning methods, study of the basic chemistry of trans-curium elements in molten salts, study of the conditioning of the wastes, some system studies. Moreover, a strong management team will be concerned not only with the technical and financial issues arising from EUROPART, but also with information, communication and benefits for Europe. Training and education of young researchers will also pertain to the project. EUROPART has also established collaboration with US DOE and Japanese CRIEPI. (authors)

  16. A new look at actinide recycle

    International Nuclear Information System (INIS)

    Burch, W.D.; Croff, A.G.; Rawlins, J.A.; Schulz, W.W.

    1991-01-01

    This paper will address the justification for reexamination of the value of recovering the minor actinides and certain fission products from spent light-water reactor fuels and describe some of the technical progress that has been made since the major studies of a decade ago. During this time, the US Environmental Protection Agency (EPA) and the Nuclear Regulatory Commission have begun establishing detailed criteria and regulations for geologic repositories. An examination of the hazards of waste disposal relative to the EPA release standards reveals that removal of 99.9% of the actinides (Pu, Am, and Np) reduces these hazards quite close to the EPA standards after 300 years' decay of the strontium and cesium. It may be also useful to remove and separately manage and dispose of certain of the long-lived fission products, such as 99 Tc and 129 I. Much additional work is required to fully assess the appropriate target recoveries as the hazards and risks are more closely examined and as the standards are reworked and refined. The two decades before the projected start of the US repository may present a window of opportunity to introduce several better management practices that act to simplify the repository safety issues. From a technical standpoint, significant progress has been made on recovery of the actinides from aqueous wastes though use of the TRUEX process. Additional work is required to demonstrate the application of the process to spent LWR fuels, but it appears straightforward. In addition, work at the Argonne National Laboratory on the liquid-metal reactor metal fuel cycle shows the relative simplicity of recycle of the actinides in that fast reactor cycle. Much work remains to fully demonstrate that actinides from all secondary waste streams can be removed to the target levels from both the aqueous reprocessing of LWR fuel and the pyro processes for the metal-fueled fast reactor. 9 refs., 2 figs

  17. Synroc tailored waste forms for actinide immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Gregg, Daniel J.; Vance, Eric R. [Australian Nuclear Science and Technology Organisation, Kirrawee (Australia). ANSTOsynroc, Inst. of Materials Engineering

    2017-07-01

    Since the end of the 1970s, Synroc at the Australian Nuclear Science and Technology Organisation (ANSTO) has evolved from a focus on titanate ceramics directed at PUREX waste to a platform waste treatment technology to fabricate tailored glass-ceramic and ceramic waste forms for different types of actinide, high- and intermediate level wastes. The particular emphasis for Synroc is on wastes which are problematic for glass matrices or existing vitrification process technologies. In particular, nuclear wastes containing actinides, notably plutonium, pose a unique set of requirements for a waste form, which Synroc ceramic and glass-ceramic waste forms can be tailored to meet. Key aspects to waste form design include maximising the waste loading, producing a chemically durable product, maintaining flexibility to accommodate waste variations, a proliferation resistance to prevent theft and diversion, and appropriate process technology to produce waste forms that meet requirements for actinide waste streams. Synroc waste forms incorporate the actinides within mineral phases, producing products which are much more durable in water than baseline borosilicate glasses. Further, Synroc waste forms can incorporate neutron absorbers and {sup 238}U which provide criticality control both during processing and whilst within the repository. Synroc waste forms offer proliferation resistance advantages over baseline borosilicate glasses as it is much more difficult to retrieve the actinide and they can reduce the radiation dose to workers compared to borosilicate glasses. Major research and development into Synroc at ANSTO over the past 40 years has included the development of waste forms for excess weapons plutonium immobilization in collaboration with the US and for impure plutonium residues in collaboration with the UK, as examples. With a waste loading of 40-50 wt.%, Synroc would also be considered a strong candidate as an engineered waste form for used nuclear fuel and highly

  18. FY2011 Annual Report for the Actinide Isomer Detection Project

    International Nuclear Information System (INIS)

    Warren, Glen A.; Francy, Christopher J.; Ressler, Jennifer J.; Erikson, Luke E.; Tatishvili, Gocha; Hatarik, R.

    2011-01-01

    This project seeks to identify a new signature for actinide element detection in active interrogation. This technique works by exciting and identifying long-lived nuclear excited states (isomers) in the actinide isotopes and/or primary fission products. Observation of isomers in the fission products will provide a signature for fissile material. For the actinide isomers, the decay time and energy of the isomeric state is unique to a particular isotope, providing an unambiguous signature for SNM. This project entails isomer identification and characterization and neutron population studies. This document summarizes activities from its third year - completion of the isomer identification characterization experiments and initialization of the neutron population experiments. The population and decay of the isomeric state in 235U remain elusive, although a number of candidate gamma rays have been identified. In the course of the experiments, a number of fission fragment isomers were populated and measured (Ressler 2010). The decays from these isomers may also provide a suitable signature for the presence of fissile material. Several measurements were conducted throughout this project. This report focuses on the results of an experiment conducted collaboratively by PNNL, LLNL and LBNL in December 2010 at LBNL. The measurement involved measuring the gamma-rays emitted from an HEU target when bombarded with 11 MeV neutrons. This report discussed the analysis and resulting conclusions from those measurements. There was one strong candidate, at 1204 keV, of an isomeric signature of 235U. The half-life of the state is estimated to be 9.3 μs. The measured time dependence fits the decay time structure very well. Other possible explanations for the 1204-keV state were investigated, but they could not explain the gamma ray. Unfortunately, the relatively limited statistics of the measurement limit, and the lack of understanding of some of the systematic of the experiment, limit

  19. Laboratory actinide partitioning: Whitlockite/liquid and influence of actinide concentration levels

    International Nuclear Information System (INIS)

    Benjamin, T.M.; Jones, J.H.; Heuser, W.R.; Burnett, D.S.

    1983-01-01

    Fission and alpha track radiography techniques have been used to measure partition coefficients (D) at trace (ppm) concentration levels for the actinide elements Th, U, and Pu between synthetic whitlockite and coexisting 'haplobasaltic' silicate liquid at 1 bar pressure and 1250 deg C at oxygen fugacities from 10 sup(-8.5) and 10sup(-0.7) bars. Pu is much more readily incorporated into crystalline phases than is U or Th under reducing conditions, because Pu is primarily trivalent, whereas U and Th are tetravalent. Definitive valence state assignments cannot be made, but our best estimates of corrected partition coefficients for Pu +3 , Pu +4 , Th +4 , U +4 , and U +6 are given for whitlockites. The effect of changing pressure and liquidus temperature is relatively small, which probably reflects a weak temperature dependence for D (whitlockite) but possibly could be due to cancellation of opposing temperature and pressure effects. Comparison of experiments at trace U levels with those containing percent concentrations of UO 2 indicate that Si is involved in the substitution of U in whitlockite with U + 2Si Ca + 2P being the most likely mechanism. Dsub(U) is lower, 0.3 vs 0.5, at percent levels compared to 20 ppm. This is best explained by the effect of U on melt structure or by a decrease in the fraction of tetravalent U at high concentrations. (author)

  20. Lipofection of insulin-producing RINm5F cells: methodological improvements.

    Science.gov (United States)

    Barbu, Andreea; Welsh, Nils

    2007-01-01

    Cationic lipid/DNA-complexes have been widely used as gene transfer vectors because they are less toxic and immunogenic than viral vectors. The aim of the present study was to improve and characterize lipofection of an insulin-producing cell line. We compared the transfection efficiency of seven commercially available lipid formulations (Lipotaxi, SuperFect, Fugene, TransFast, Dosper, GenePORTER and LipofectAMINE) by flow cytometry analysis of GFP-expression. In addition, we have determined the influences of centrifugation, serum and a nuclear localization signal peptide on the lipofection efficiency. We observed that two lipid formulations, GenePORTER and LipofectAMINE, were able to promote efficient gene transfer in RINm5F cells. However, GenePORTER exhibited the important advantage of being able to transfect cells in the presence of serum and with less cytotoxicity than LipofectAMINE. LipofectAMINE-induced RINm5F cell death could partially be counteracted by TPA, forskolin or fumonisin beta(1). Finally, both centrifugation and a nuclear localization signal peptide increased transfection efficiency.

  1. Theoretical study of the structure and the reactivity of lanthanides and actinides complexes: Activation of small molecules

    International Nuclear Information System (INIS)

    Castro, Ludovic

    2012-01-01

    This PhD thesis presents a theoretical study of the structure and the reactivity of organometallic complexes of lanthanides and actinides at the DFT level. After a general introduction of the methods of theoretical chemistry used for the modelling of organometallic reactivity, a study of the participation of 5f electrons in uranium(IV) reactivity is presented. The results show that the large core ECP can be used safely in order to treat the actinide and so that 5f electrons can be treated implicitly. Then, the reactivity of uranium(III) complexes with CO 2 and other analogous molecules is studied via multiple examples from the literature. These studies show that the steric nature of the ligands is very important and controls the reactivity. This study is then extended to samarium(II) complex. Eventually, the reactivity of a hydride complex of cerium(III) with MeOSO 2 Me is investigated and theoretical results are compared with experimental observations. (author) [fr

  2. Multifaceted Modularity: A Key for Stepwise Building of Hierarchical Complexity in Actinide Metal–Organic Frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Dolgopolova, Ekaterina A. [Department; Ejegbavwo, Otega A. [Department; Martin, Corey R. [Department; Smith, Mark D. [Department; Setyawan, Wahyu [Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Karakalos, Stavros G. [College; Henager, Charles H. [Pacific Northwest National Laboratory, Richland, Washington 99352, United States; zur Loye, Hans-Conrad [Department; Shustova, Natalia B. [Department

    2017-11-07

    Growing necessity for efficient nuclear waste management is a driving force for development of alternative architectures towards fundamental understanding of mechanisms involved in actinide integration inside extended structures. In this manuscript, metal-organic frameworks (MOFs) were investigated as a model system for engineering radionuclide containing materials through utilization of unprecedented MOF modularity, which cannot be replicated in any other type of materials. Through the implementation of recent synthetic advances in the MOF field, hierarchical complexity of An-materials were built stepwise, which was only feasible due to preparation of the first examples of actinide-based frameworks with “unsaturated” metal nodes. The first successful attempts of solid-state metathesis and metal node extension in An-MOFs are reported, and the results of the former approach revealed drastic differences in chemical behavior of extended structures versus molecular species. Successful utilization of MOF modularity also allowed us to structurally characterize the first example of bimetallic An-An nodes. To the best of our knowledge, through combination of solid-state metathesis, guest incorporation, and capping linker installation, we were able to achieve the highest Th wt% in mono- and bi-actinide frameworks with minimal structural density. Overall, combination of a multistep synthetic approach with homogeneous actinide distribution and moderate solvothermal conditions could make MOFs an exceptionally powerful tool to address fundamental questions responsible for chemical behavior of An-based extended structures, and therefore, shed light on possible optimization of nuclear waste administration.

  3. Orbitally-driven magnetism in light actinide systems

    International Nuclear Information System (INIS)

    Cooper, B.R.; Los Alamos National Lab.

    1987-01-01

    We are interested in understanding the solid-state behavior characteristic of the transition regime between itinerant (bonding) and localized (correlated ionic) f-electron behavior in light actinide (uranium, neptunium and plutonium) systems. For the light actinides, the degree of f-electron localization is sensitive to chemical environment and varies widely depending on specific compound or alloy. It is important for any meaningful theory to reflect this sensitivity to chemical environment. We have focussed our attention initially on magnetic behavior, since the pertinent orbitally-driven magnetic behavior is both interesting in itself and valuable as a diagnostic tool for the f-electron behavior and sensitivity to chemical environment. The key aspect of the electronic behavior is the hybridization (mixing) of the f electrons with band electrons of other than f atomic parentage. To treat effects of hybridization quantitatively, we transform the physical mixing mathematically to resonant scattering of band electrons off f electrons. Anisotropic magnetic properties provide a way to measure the weighting of resonant scattering channels, and this weighting reflects the sensitivity to chemical environment. (orig.)

  4. Quantities of actinides in nuclear reactor fuel cycles

    International Nuclear Information System (INIS)

    Ang, K.P.

    1975-01-01

    The quantities of plutonium and other fuel actinides have been calculated for equilibrium fuel cycles for 1000 MW reactors of the following types: water reactors fueled with slightly enriched uranium, water reactors fueled with plutonium and natural uranium, fast-breeder reactors, gas-cooled reactors fueled with thorium and highly enriched uranium, and gas-cooled reactors fueled with thorium, plutonium, and recycled uranium. The radioactivity levels of plutonium, americium, and curium processed yearly in these fuel cycles are greatest for the water reactors fueled with natural uranium and recycled plutonium. The total amount of actinides processed is calculated for the predicted future growth of the United States nuclear power industry. For the same total installed nuclear power capacity, the introduction of the plutonium breeder has little effect upon the total amount of plutonium processed in this century. The estimated amount of plutonium in the low-level process wastes in the plutonium fuel cycles is comparable to the amount of plutonium in the high-level fission product wastes. The amount of plutonium processed in the nuclear fuel cycles can be considerably reduced by using gas-cooled reactors to consume plutonium produced in uranium-fueled water reactors. These, and other reactors dedicated for plutonium utilization, could be co-located with facilities for fuel reprocessing and fuel fabrication to eliminate the off-site transport of separated plutonium. (U.S.)

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  6. Calculation of thermodynamic properties and transport coefficients of C5F10O-CO2 thermal plasmas

    Science.gov (United States)

    Li, Xingwen; Guo, Xiaoxue; Murphy, Anthony B.; Zhao, Hu; Wu, Jian; Guo, Ze

    2017-10-01

    The thermodynamic properties and transport coefficients of C5F10O-CO2 gas mixtures, which are being considered as substitutes for SF6 in circuit breaker applications, are calculated for the temperature range from 300 K to 30 000 K and the pressure range from 0.05 MPa to 1.6 MPa. Special attention is paid on investigating the evolution of thermophysical properties of C5F10O-CO2 mixtures with different mixing ratios and with different pressures; both the mixing ratio and pressure significantly affect the properties. This is explained mainly in terms of the changes in the temperatures at which the dissociation and ionization reactions take place. Comparisons of different thermophysical properties of C5F10O-CO2 mixtures with those of SF6 are also carried out. It is found that most of the thermophysical properties of the C5F10O-CO2 mixtures, such as thermal conductivity, viscosity, and electrical conductivity, become closer to those of SF6 as the C5F10O concentration increases. The composition and thermophysical properties of pure C5F10O in the temperature range from 300 K to 2000 K based on the decomposition pathway are also given. The calculation results provide a basis for further study of the insulation and arc-quenching capability of C5F10O-CO2 gas mixtures as substitutes for SF6.

  7. Electrorecovery of actinides at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Stoll, Michael E [Los Alamos National Laboratory; Oldham, Warren J [Los Alamos National Laboratory; Costa, David A [Los Alamos National Laboratory

    2008-01-01

    There are a large number of purification and processing operations involving actinide species that rely on high-temperature molten salts as the solvent medium. One such application is the electrorefining of impure actinide metals to provide high purity material for subsequent applications. There are some drawbacks to the electrodeposition of actinides in molten salts including relatively low yields, lack of accurate potential control, maintaining efficiency in a highly corrosive environment, and failed runs. With these issues in mind we have been investigating the electrodeposition of actinide metals, mainly uranium, from room temperature ionic liquids (RTILs) and relatively high-boiling organic solvents. The RTILs we have focused on are comprised of 1,3-dialkylimidazolium or quaternary ammonium cations and mainly the {sup -}N(SO{sub 2}CF{sub 3}){sub 2} anion [bis(trif1uoromethylsulfonyl)imide {equivalent_to} {sup -}NTf{sub 2}]. These materials represent a class of solvents that possess great potential for use in applications employing electrochemical procedures. In order to ascertain the feasibility of using RTILs for bulk electrodeposition of actinide metals our research team has been exploring the electron transfer behavior of simple coordination complexes of uranium dissolved in the RTIL solutions. More recently we have begun some fundamental electrochemical studies on the behavior of uranium and plutonium complexes in the organic solvents N-methylpyrrolidone (NMP) and dimethylsulfoxide (DMSO). Our most recent results concerning electrodeposition will be presented in this account. The electrochemical behavior of U(IV) and U(III) species in RTILs and the relatively low vapor pressure solvents NMP and DMSO is described. These studies have been ongoing in our laboratory to uncover conditions that will lead to the successful bulk electrodeposition of actinide metals at a working electrode surface at room temperature or slightly elevated temperatures. The RTILs we

  8. NMR studies of actinide carbide and nitride electronic properties

    International Nuclear Information System (INIS)

    Boutard, Jean-Louis

    1976-12-01

    N.M.R. studies applied to 13 C and 15 N in the solid solutions ThCsub(1-x)Nsub(x), UCsub(1-x)Nsub(x) and in the compounds ThCsub(1-x) and U 2 C 3 , were undertaken to study carbon and nitrogen contribution to chemical bonds and magnetism. For THORIUM MONOCARBIDE AND CARBONITRIDE: ThCsub(1-x) and ThCsub(1-x)Nsub(x), the very strong orbital contribution to the frequency shift reveals an important covalent character of the valence band 6d metal and 2p metalloid states. The ThCsub(1-x) band structure stoichiometry variation is due to 6dγ metal states appearing at the Fermi level and is in-opposition to a rigid band model. A non-saturated bond mechanism is suggested. For URANIUM CARBONITRIDE: UCsub(1-x)Nsub(x), in the concentration range in which no magnetic order appears at low temperature (x<0.90), the results are in opposition to a localized 5f 2 configuration model, and show that the uranium fundamental state is non-magnetic. Nevertheless two qualitatively different behaviors exist: nitrogen concentration lower than 40%: and nitrogen concentration higher than 40%. A model is proposed to account for those domains: it relies on the 5f-2p hybridization parameter which is maximum on 2p band edge (UC) and almost nul for UN. For URANIUM SESQUICARBIDE: U 2 C 3 : the N.M.R. line observation at 4.2 K indicates a non-magnetic fundamental state although the magnetic susceptibility presents a maximum at 60 K. Spin fluctuations in 5f bands are proposed to describe the electronic properties of this compound. [fr

  9. Beneficial Effect of Jojoba Seed Extracts on Hyperglycemia-Induced Oxidative Stress in RINm5f Beta Cells.

    Science.gov (United States)

    Belhadj, Sahla; Hentati, Olfa; Hamdaoui, Ghaith; Fakhreddine, Khaskhoussi; Maillard, Elisa; Dal, Stéphanie; Sigrist, Séverine

    2018-03-20

    Hyperglycemia occurs during diabetes and insulin resistance. It causes oxidative stress by increasing reactive oxygen species (ROS) levels, leading to cellular damage. Polyphenols play a central role in defense against oxidative stress. In our study, we investigated the antioxidant properties of simmondsin, a pure molecule present in jojoba seeds, and of the aqueous extract of jojoba seeds on fructose-induced oxidative stress in RINm5f beta cells. The exposure of RINm5f beta cells to fructose triggered the loss of cell viability (-48%, p jojoba seed extract makes jojoba a powerful agent to prevent the destruction of RINm5f beta cells induced by hyperglycemia.

  10. Recovery of actinides from actinide-aluminium alloys by chlorination: Part I

    Energy Technology Data Exchange (ETDEWEB)

    Cassayre, L., E-mail: cassayre@chimie.ups-tlse.fr [Laboratoire de Genie Chimique (LGC), Departement Procedes Electrochimiques, CNRS-UMR 5503, Universite de Toulouse III - Paul Sabatier, 31062 Toulouse (France); Soucek, P.; Mendes, E.; Malmbeck, R.; Nourry, C.; Eloirdi, R.; Glatz, J.-P. [European Commission, JRC, Institute for Transuranium Elements, Postfach 2340, 76125 Karlsruhe (Germany)

    2011-07-01

    Pyrochemical processes in molten LiCl-KCl are being developed in ITU for recovery of actinides from spent nuclear fuel. The fuel is anodically dissolved to the molten salt electrolyte and actinides are electrochemically reduced on solid aluminium cathodes forming solid actinide-aluminium alloys. A chlorination route is being investigated for recovery of actinides from the alloys. This route consists in three steps: Vacuum distillation for removal of the salt adhered on the electrode, chlorination of the actinide-aluminium alloys by chlorine gas and sublimation of the formed AlCl{sub 3}. A thermochemical study showed thermodynamic feasibility of all three steps. On the basis of the conditions identified by the calculations, experiments using pure UAl{sub 3} alloy were carried out to evaluate and optimise the chlorination step. The work was focused on determination of the optimal temperature and Cl{sub 2}/UAl{sub 3} molar ratio, providing complete chlorination of the alloy without formation of volatile UCl{sub 5} and UCl{sub 6}. The results showed high efficient chlorination at a temperature of 150 deg. C.

  11. Recovery of actinides from actinide-aluminium alloys by chlorination: Part I

    International Nuclear Information System (INIS)

    Cassayre, L.; Soucek, P.; Mendes, E.; Malmbeck, R.; Nourry, C.; Eloirdi, R.; Glatz, J.-P.

    2011-01-01

    Pyrochemical processes in molten LiCl-KCl are being developed in ITU for recovery of actinides from spent nuclear fuel. The fuel is anodically dissolved to the molten salt electrolyte and actinides are electrochemically reduced on solid aluminium cathodes forming solid actinide-aluminium alloys. A chlorination route is being investigated for recovery of actinides from the alloys. This route consists in three steps: Vacuum distillation for removal of the salt adhered on the electrode, chlorination of the actinide-aluminium alloys by chlorine gas and sublimation of the formed AlCl 3 . A thermochemical study showed thermodynamic feasibility of all three steps. On the basis of the conditions identified by the calculations, experiments using pure UAl 3 alloy were carried out to evaluate and optimise the chlorination step. The work was focused on determination of the optimal temperature and Cl 2 /UAl 3 molar ratio, providing complete chlorination of the alloy without formation of volatile UCl 5 and UCl 6 . The results showed high efficient chlorination at a temperature of 150 deg. C.

  12. Minor actinide transmutation on PWR burnable poison rods

    International Nuclear Information System (INIS)

    Hu, Wenchao; Liu, Bin; Ouyang, Xiaoping; Tu, Jing; Liu, Fang; Huang, Liming; Fu, Juan; Meng, Haiyan

    2015-01-01

    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 k eff 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 k eff markedly. The PWR k eff 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

  13. Dualism of the 5f electrons of the ferromagnetic superconductor UGe2 as seen in magnetic, transport, and specific-heat data

    Science.gov (United States)

    Troć, R.; Gajek, Z.; Pikul, A.

    2012-12-01

    Single-crystalline UGe2 was investigated by means of magnetic susceptibility, magnetization, electrical resistivity, magnetoresistivity, and specific-heat measurements, all carried out in wide temperature and magnetic-field ranges. An analysis of the obtained data points out the dual behavior of the 5f electrons in this compound, i.e., possessing simultaneously local and itinerant characters in two substates. The magnetic and thermal characteristics of the compound were modeled using the effective crystal field (CF) in the intermediate coupling scheme and initial parameters obtained in the angular overlap model. Various configurations of the localized 5fn (n = 1, 2, and 3) electrons on the uranium ion have been probed. The best results were obtained for the 5f2 (U4+) configuration. The CF parameters obtained in the paramagnetic region allowed us to reproduce satisfactorily the experimental findings in the whole temperature range including also the magnitude of the ordered magnetic moment of uranium at low temperature. The electrical resistivity data after subtraction of the phonon contribution reveal the presence of a Kondo-like interaction in UGe2 supporting the idea of partial localization of the 5f electrons in UGe2. On the other hand, magnetoresistivity and an excess of specific heat originated from the hybridized (itinerant) part of 5f states, apparent around the characteristic temperature T*, give a distinct signature for the presence of the coupled charge-density wave and spin-density wave fluctuations over all the ferromagnetic region with a maximum at T*, postulated earlier in the literature.

  14. On the solvation of actinide ions

    International Nuclear Information System (INIS)

    Hagberg, D.

    2007-01-01

    Complete text of publication follows: Simulation of the universal ions in water solution is a standardized tool commonly used today. The route to simulation of actinide ions is normally tough because the evaluation of the simulation parameters are normally not given empirically and standard Hartree-Fock calculations are not accurate enough. We use multiconfigurational quantum chemical calculations when deriving the parameters for actinide ion-water potential [1]. The parameters are then simulated using classical molecular dynamics. A case study of the Cm 3+ ion will be presented on the poster. Results from the simulations will be also be discussed, e.g. the radial distribution functions and the coordination number. [1] D. Hagberg, G. Karlstrom, B.O. Roos and L. Gagliardi The coordination of uranyl in water: a combined quantum chemical and molecular simulation study J. Am. Chem. Soc. 127, 14250-14256 (2005)

  15. Rapid ion-exchange separations of actinides

    International Nuclear Information System (INIS)

    Usuda, Shigekazu

    1988-01-01

    For the purpose of studying short-lived actinide nuclides, three methods for rapid ion exchange separation of actinide elements with mineral acid-alcohol mixed media were developed: anion exchange with nitric acid-methyl alcohol mixed media to separate the transplutonium and rare earth elements from target material, U or Pu and Al catcher foils; anion exchange with hydrochloric acid-methyl alcohol media to separate Am+Cm, Bk and Cf+Fm from the target, catcher foils and major fission products; and cation exchange with hydrochloric acid-methyl alcohol media and with concentrated hydrochloric acid to separate the transplutonium elements as a group from the rare earths after eliminating the large amounts of U, Al, Cu, Fe etc. The methods enable one to perform rapid and effective separation at elevated temperature (90 deg C) and immediate source preparation for alpha-ray spectrometry. (author) 47 refs.; 10 figs

  16. Actinide and fission product separation and transmutation

    Energy Technology Data Exchange (ETDEWEB)

    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.)

  17. Actinide and fission product separation and transmutation

    International Nuclear Information System (INIS)

    1991-01-01

    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.)

  18. Seventeen-coordinate actinide helium complexes

    Energy Technology Data Exchange (ETDEWEB)

    Kaltsoyannis, Nikolas [School of Chemistry, The University of Manchester (United Kingdom)

    2017-06-12

    The geometries and electronic structures of molecular ions featuring He atoms complexed to actinide cations are explored computationally using density functional and coupled cluster theories. A new record coordination number is established, as AcHe{sub 17}{sup 3+}, ThHe{sub 17}{sup 4+}, and PaHe{sub 17}{sup 4+} are all found to be true geometric minima, with the He atoms clearly located in the first shell around the actinide. Analysis of AcHe{sub n}{sup 3+} (n=1-17) using the quantum theory of atoms in molecules (QTAIM) confirms these systems as having closed shell, charge-induced dipole bonding. Excellent correlations (R{sup 2}>0.95) are found between QTAIM metrics (bond critical point electron densities and delocalization indices) and the average Ac-He distances, and also with the incremental He binding energies. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Actinide uptake by transferrin and ferritin metalloproteins

    International Nuclear Information System (INIS)

    Den Auwer, C.; Llorens, I.; Moisy, Ph.; Vidaud, C.; Goudard, F.; Barbot, C.; Solari, P.L.; Funke, H.

    2005-01-01

    In order to better understand the mechanisms of actinide uptake by specific biomolecules, it is essential to explore the intramolecular interactions between the cation and the protein binding site. Although this has long been done for widely investigated transition metals, very few studies have been devoted to complexation mechanisms of actinides by active chelation sites of metalloproteins. In this field, X-ray absorption spectroscopy has been extensively used as a structural and electronic metal cation probe. The two examples that are presented here are related to two metalloproteins in charge of iron transport and storage in eukaryote cells: transferrin and ferritin. U(VI)O 2 2+ , Np(IV) and Pu(IV) have been selected because of their possible role as contaminant from the geosphere. (orig.)

  20. Minor actinide transmutation in accelerator driven systems

    Energy Technology Data Exchange (ETDEWEB)

    Friess, Friederike [IANUS, TU Darmstadt (Germany)

    2015-07-01

    Transmutation of radioactive waste, the legacy of nuclear energy use, gains rising interest. This includes the development of facilities able to transmute minor actinides (MA) into stable or short-lived isotopes before final disposal. The most common proposal is to use a double-strata approach with accelerator-driven-systems (ADS) for the efficient transmutation of MA and power reactors to dispose plutonium. An ADS consists of a sub-critical core that reaches criticality with neutrons supplied by a spallation target. An MCNP model of the ADS system Multi Purpose Research Reactor for Hightech Applications will be presented. Depletion calculations have been performed for both standard MOX fuel and transmutation fuel with an increased content of minor actinides. The resulting transmutation rates for MAs are compared to published values. Special attention is given to selected fission products such as Tc-99 and I-129, which impact the radiation from the spent fuel significantly.

  1. Establishment and use of national registries for actinide elements in humans

    International Nuclear Information System (INIS)

    1996-05-01

    This TECDOC covers all aspects of the establishment and use of registries for actinide elements in Member States. These aspects include assessing the need for such registries; defining scope of the work and developing objectives; administration; organization and staffing; policies; practices; procedures; protocols; registration and enrollment; data collection and evaluation; establishing and analytical laboratory; publication of results and application of findings. Not all aspects will be relevant to all Member States establishing such registries. 1 tab

  2. Establishment and use of national registries for actinide elements in humans

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-05-01

    This TECDOC covers all aspects of the establishment and use of registries for actinide elements in Member States. These aspects include assessing the need for such registries; defining scope of the work and developing objectives; administration; organization and staffing; policies; practices; procedures; protocols; registration and enrollment; data collection and evaluation; establishing and analytical laboratory; publication of results and application of findings. Not all aspects will be relevant to all Member States establishing such registries. 1 tab.

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

    International Nuclear Information System (INIS)

    Novak, C.F.; Papenguth, H.W.; Crafts, C.C.; Dhooge, N.J.

    1994-01-01

    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

  4. Actinides reduction by recycling in a thermal reactor

    International Nuclear Information System (INIS)

    Ramirez S, J. R.; Martinez C, E.; Balboa L, H.

    2014-10-01

    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)

  5. Strength of Coriolis Coupling in actinide nuclei

    International Nuclear Information System (INIS)

    Peker, L.K.; Rasmussen, J.O.; Hamilton, J.H.

    1982-01-01

    Coriolis Coupling V/sub cor/ plays an important role in deformed nuclei. V/sub cor/ is proportional to h 2 /J[j (j + 1) -Ω (Ω + 1)]/sup 1/2/ and therefore is particularly significant in the nuclei with large j and low Ω Nilsson levels close to Fermi surface: n(i/sub 13/2/) in A = 150 to 170 rare-earth nuclei and p(i/sub 13/2/) and n(j/sub 15/2/) in A greater than or equal to 224 actinide nuclei. Because of larger j (n(j/sub 15/2/) versus n(i/sub 13/2/)) and smaller deformations (β approx. = 0.22 versus β 0.28) it was reasonable to expect that in actinide nuclei Coriolis effects are stronger than in the rare earth nuclei. Recently it was realized that the strength of observed Coriolis effects depends not only on the genuine Coriolis Coupling but also on the interplay between Coriolis ad pairing forces which leads to an interference between the wave functions of two mixing rotational bands. As a consequence the effective interaction V/sub eff/ of both bands is an oscillating function of the degree of shell filling (or chemical potential lambda F). It was shown that in the rare earth nuclei this interference strongly influenced conclusions about the trends in the Coriolis coupling strength and explained many of the observed band-mixing features (the sharpness of back banding curves, details of the blocking effect etc.). From theoretical analysis it was concluded that in the majority of actinide nuclei the effective interaction V/sub eff/ is strong, and therefore the Coriolis band-mixing have to be very strong. In this paper we would like to demonstrate that contrary to these predictions experimental data suggest that Coriolis band mixing in studied actinide nuclei is relatively weak and possibly significantly weaker than in rare earth nuclei

  6. Actinide and fission product partitioning and transmutation

    Energy Technology Data Exchange (ETDEWEB)

    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.)

  7. Actinide burning in the integral fast reactor

    International Nuclear Information System (INIS)

    Chang, Y.I.

    1993-01-01

    During the past few years, Argonne National Laboratory has been developing the integral fast reactor (IFR), an advanced liquid-metal reactor concept. In the IFR, the inherent properties of liquid-metal cooling are combined with a new metallic fuel and a radically different refining process to allow breakthroughs in passive safety, fuel cycle economics, and waste management. A key feature of the IFR concept is its unique pyroprocessing. Pyroprocessing has the potential to radically improve long-term waste management strategies by exploiting the following attributes: 1. Minor actinides accompany plutonium product stream; therefore, actinide recycling occurs naturally. Actinides, the primary source of long-term radiological toxicity, are removed from the waste stream and returned to the reactor for in situ burning, generating useful energy. 2. High-level waste volume from pyroprocessing call be reduced substantially as compared with direct disposal of spent fuel. 3. Decay heat loading in the repository can be reduced by a large factor, especially for the long-term burden. 4. Low-level waste generation is minimal. 5. Troublesome fission products, such as 99 Tc, 129 I, and 14 C, are contained and immobilized. Singly or in combination, the foregoing attributes provide important improvements in long-term waste management in terms of the ease in meeting technical performance requirements (perhaps even the feasibility of demonstrating that technical performance requirements can be met) and perhaps also in ultimate public acceptance. Actinide recycling, if successfully developed, could well help the current repository program by providing an opportunity to enhance capacity utilization and by deferring the need for future repositories. It also represents a viable technical backup option in the event unforeseen difficulties arise in the repository licensing process

  8. Actinides and lanthanides under pressure: the pseudopotential approach; Actinides et terres rares sous pression: approche pseudopotentiel

    Energy Technology Data Exchange (ETDEWEB)

    Richard, N

    2002-07-01

    In the Density Functional Theory Framework, the pseudopotential formalism offers a broader scope of study than other theoretical methods such as global relaxation of the parameters of the cell or ab initio molecular dynamics simulations. This method has been widely used to study light elements or transition metals but never to study f elements. We have generated two non local norm conserving Trouillier-Martins pseudopotentials (one in LDA and one in GGA) for the cerium. To check the validity of the pseudopotentials, we have calculated the equilibrium volume and the incompressibility modulus and compared our results to previous all-electron calculations. If the GGA and non linear core corrections are used, the equation of state is in a good agreement with the experimental equation of state. A static study of the previously proposed high pressure phases give a transitions fcc-a''(I)-bct. Using the pseudopotentials we have generated, an ab initio molecular dynamics simulation at constant pressure, in the region between 5 and 12 GPa where the stable phase of cerium is not well defined, lead us to predict that a centred monoclinic structure, as the a''(I) phase previously observed in some experiments, is the most stable phase. We have also generated pseudopotentials for the light actinides (Th, Pa, U and Np). We have study their phase transitions under pressure at zero temperature. We compared our results with all electron results. The structure parameters have always been relaxed in this study. And for the first time in pseudopotential calculation, the spin-orbit coupling has been taken into account. The curves describing the variation of the volume or the incompressibility modulus depending on the elements and the phase transitions are always in agreement with the one found in the all electron calculations. (author)

  9. BWR Assembly Optimization for Minor Actinide Recycling

    International Nuclear Information System (INIS)

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

    2010-01-01

    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). A top-level objective of the Advanced Fuel Cycle Systems Analysis program element of the DOE NERI program is to investigate spent fuel treatment and recycling options for current light water reactors (LWRs). Accordingly, this project targets to expand the traditional scope of nuclear fuel management optimization into the following two complementary specific objectives: (1) To develop a direct coupling between the pin-by-pin within-bundle loading control variables and core-wide (bundle-by-bundle) optimization objectives, (2) to extend the methodology developed to explicitly encompass control variables, objectives, and constraints designed to maximize minor actinide incineration in BWR bundles and cycles. The first specific objective is projected to 'uncover' dormant thermal margin made available by employing additional degrees of freedom within the optimization process, while the addition of minor actinides is expected to 'consume' some of the uncovered thermal margin. Therefore, a key underlying goal of this project is to effectively invest some of the uncovered thermal margin into achieving the primary objective.

  10. Measurement of actinide neutron cross sections

    International Nuclear Information System (INIS)

    Firestone, Richard B.; Nitsche, Heino; Leung, Ka-Ngo; Perry, DaleL.; English, Gerald

    2003-01-01

    The maintenance of strong scientific expertise is critical to the U.S. nuclear attribution community. It is particularly important to train students in actinide chemistry and physics. Neutron cross-section data are vital components to strategies for detecting explosives and fissile materials, and these measurements require expertise in chemical separations, actinide target preparation, nuclear spectroscopy, and analytical chemistry. At the University of California, Berkeley and the Lawrence Berkeley National Laboratory we have trained students in actinide chemistry for many years. LBNL is a leader in nuclear data and has published the Table of Isotopes for over 60 years. Recently, LBNL led an international collaboration to measure thermal neutron capture radiative cross sections and prepared the Evaluated Gamma-ray Activation File (EGAF) in collaboration with the IAEA. This file of 35, 000 prompt and delayed gamma ray cross-sections for all elements from Z=1-92 is essential for the neutron interrogation of nuclear materials. LBNL has also developed new, high flux neutron generators and recently opened a 1010 n/s D+D neutron generator experimental facility

  11. Value of burnup credit beyond actinides

    International Nuclear Information System (INIS)

    Lancaster, D.; Fuentes, E.; Kang, Chi.

    1997-01-01

    DOE has submitted a topical report to the NRC justifying burnup credit based only on actinide isotopes (U-234, U-235, U-236, U-238, Pu-238, Pu-239, Pu-240, Pu-241, Pu-242, and Am-241). When this topical report is approved, it will allow a great deal of the commercial spent nuclear fuel to be transported in significantly higher capacity casks. A cost savings estimate for shipping fuel in 32 assembly (burnup credit) casks as opposed to 24 assembly (non-burnup credit) casks was previously presented. Since that time, more detailed calculations have been performed using the methodology presented in the Actinide-Only Burnup Credit Topical Report. Loading curves for derated casks have been generated using actinide-only burnup credit and are presented in this paper. The estimates of cost savings due to burnup credit for shipping fuel utilizing 32, 30, 28, and 24 assembly casks where only the 24 assembly cask does not burnup credit have been created and are discussed. 4 refs., 2 figs

  12. Study on remain actinides recovery in pyro reprocessing

    International Nuclear Information System (INIS)

    Suharto, Bambang

    1996-01-01

    The spent fuel reprocessing by dry process called pyro reprocessing have been studied. Most of U, Pu and MA (minor actinides) from the spent fuel will be recovered and be fed back to the reactor as new fuel. Accumulation of remain actinides will be separated by extraction process with liquid cadmium solvent. The research was conducted by computer simulation to calculate the stage number required. The calculation's results showed on the 20 stages extractor more than 99% actinides can be separated. (author)

  13. Actinide recycle potential in the integral fast reactor

    International Nuclear Information System (INIS)

    Chang, Y.I.

    1993-01-01

    The Integral Fast Reactor (IFR) fuel cycle holds promise for substantial improvements in economics, diversion-resistance, and waste management. In the IFR pyroprocessing, minor actinides accompany plutonium product stream, and therefore, actinide recycle occurs naturally. The fast neutron spectrum of the IFR makes it an ideal actinide burner, as well. This paper discusses technical features of the IFR fuel cycle, its technical progress, the development status, and potential implications on long-term waste management

  14. Preparation, properties, and some recent studies of the actinide metals

    International Nuclear Information System (INIS)

    Haire, R.G.

    1985-01-01

    The actinide elements form a unique series of metals. The variation in their physial properties combined with the varying availability of the different elements offers a challenge to the preparative scientist. This article provides a brief review of selected methods used for preparing μg to kg amounts of the actinide metals and the properties of these metals. In addition, some recent studies on selected actinide metals are discussed. 62 refs

  15. Hydrothermal decomposition of actinide(IV oxalates: a new aqueous route towards reactive actinide oxide nanocrystals

    Directory of Open Access Journals (Sweden)

    Walter Olaf

    2016-01-01

    Full Text Available The hydrothermal decomposition of actinide(IV oxalates (An= Th, U, Pu at temperatures between 95 and 250 °C is shown to lead to the production of highly crystalline, reactive actinide oxide nanocrystals (NCs. This aqueous process proved to be quantitative, reproducible and fast (depending on temperature. The NCs obtained were characterised by X-ray diffraction and TEM showing their size to be smaller than 15 nm. Attempts to extend this general approach towards transition metal or lanthanide oxalates failed in the 95–250 °C temperature range. The hydrothermal decomposition of actinide oxalates is therefore a clean, flexible and powerful approach towards NCs of AnO2 with possible scale-up potential.

  16. Stability constants of the fluoride complexes of actinides in aqueous solution and their correlation with fundamental properties

    International Nuclear Information System (INIS)

    Chaudhuri, N.K.; Sawant, R.M.

    1997-09-01

    Stability constants of the fluoride complexes of the actinides in different oxidation states measured by potentiometric method using fluoride ion selective electrode have been presented. Procedure and precautions required to overcome certain difficulties particular to actinide ions have been discussed. Literature data from various sources have been compiled. In order to have a reasonable comparison the stability constant (β 1 ) values obtained in diverse ionic strength media are converted to thermodynamic stability constant, β 1 0 , using Davies equation (a modification of Debye-Huckel equation). A correlation of the β 1 0 values with the fundamental properties of the actinide ions using various models available in the literature has been attempted. A semiempirical relation recently developed by Brown, Sylva and Ellis (BSE equation) appears to be most suitable. Using the values of ionic radii and best available values of the stability constants of a large number of metal ions from recent compilations a comparative study of the various models or relations available in the literature has been tried. For metal ions in general, the best correlation is obtained with the BSE equation. In an attempt to accommodate the unusual trend in the stability constants of the tetravalent actinides a modification in a parameter of the BSE equation has been proposed. Good agreement between the theoretically calculated and experimentally determined values for actinides in different oxidation states is then obtained in most of the cases. (author)

  17. Synthesis and evaluation structure/extracting and complexing properties of new bi-topic ligands for group actinides extraction

    International Nuclear Information System (INIS)

    Bisson, J.

    2011-01-01

    The aim of this project is to design and study new extractants for spent nuclear fuel reprocessing. To decrease the long-term radiotoxicity of the waste, the GANEX process is an option to homogeneously recycle actinides. All actinides (U, Np, Pu, Am, Cm) would be extracted together from a highly acidic media and separated from fission products (especially from lanthanides). In this context, fourteen new bi-topic ligands constituted of a nitrogen poly-aromatic unit from the dipyridyl-phenanthroline and dipyridyl-1,3,5-triazine families and functionalized by amid groups were synthesized. Extraction studies performed with some of these ligands confirmed their interest to selectively separate actinides at different oxidation states from an aqueous solution 3M HNO 3 . To determine the influence of ligands structure on cation complexation, a study in a homogenous media (MeOH/H 2 O) has been carried out. Electro-spray ionization mass spectrometry have been used to characterize the complexes stoichiometries formed with several cations (Eu 3+ , Nd 3+ , Am 3+ , Pu 4+ and NpO 2 + ). Stability constants, evaluated by UV-Visible spectrophotometry, confirm the selectivity of these ligands toward actinides. Lanthanides and actinides complexes have also been characterized in the solid state by infra-red spectroscopy and X-Ray diffraction. Associated to nuclear magnetic resonance experiments and DFT calculations (Density Functional Theory), a better knowledge of their coordination mode was achieved. (author) [fr

  18. Recent progress in actinide and lanthanide solvent extraction

    International Nuclear Information System (INIS)

    Musikas, C.; Hubert, H.; Benjelloun, N.; Vitorge, P.; Bonnin, M.; Forchioni, A.; Chachaty, C.

    1983-04-01

    Work in progress on actinide solvent extraction is briefly reviewed in this paper. 1 H and 31 P NMR are used to elucidate several fundamental unsolved problems concerning organophosphorous extractants often used in actinides extraction: determination of site of dialkylthiophosphate protonation and addition of basic phosphine oxide to dibutylthiophosphoric acid dimer. Extraction of Am III and Eu from high radioactivity level wastes by tetrasubsituted methylene diamides is investigated. Trivalent actinide-lanthanide group are separated by solvent extraction using soft donor ligand complexes which are more stable. The synergism of dinonylnaphtalene sulfonic acid (HDNNS) associated with several neutral donors like TBP, TOPO, amides are examined in the trivalent and tetravalent actinide extraction

  19. Biotransformation of uranium and other actinides in radioactive wastes

    International Nuclear Information System (INIS)

    Francis, A.J.

    1998-01-01

    Microorganisms affect the solubility, bioavailability, and mobility of actinides in radioactive wastes. Under appropriate conditions, actinides are solubilized or stabilized by the direct enzymatic or indirect nonenzymatic actions of microorganisms. Biotransformation of various forms of uranium (ionic, inorganic, and organic complexes) by aerobic and anaerobic microorganisms has been extensively studied, whereas limited information is available on other important actinides (Th, Np, Pu, and Am). Fundamental information on the mechanisms of biotransformation of actinides by microbes under various environmental conditions will be useful in predicting the long-term performance of waste repositories and in developing strategies for waste management and remediation of contaminated sites. (orig.)

  20. Study of Thorium Phosphate Diphosphate (TPD) formation in nitric medium for the decontamination of high activity actinides bearing effluents

    International Nuclear Information System (INIS)

    Rousselle, Jerome

    2004-01-01

    Considering several activities in the nuclear industry and research, several low-level liquids wastes (LLLW) containing actinides in nitric medium must be decontaminated before being released in the environment. These liquid wastes mainly contain significant amounts of uranium(VI), neptunium(V) and plutonium(IV). In this work, two chemical ways were studied to decontaminate LLLW then to incorporate simultaneously uranium, neptunium and plutonium in the Thorium Phosphate Diphosphate (TPD). Both ways started from a nitric solution containing thorium and the actinides considered, present at their lower stable oxidation state. The first way consisted in the initial precipitation of actinide and thorium mixed oxalate. After drying the mixture containing the powder and phosphoric acid under dried argon, a poly-phase system was obtained. It was mainly composed by a thorium-actinide oxalate-phosphate. This mixture was transformed into a TPDAn solid solution (An = U, Np and/or Pu) by heating treatment at 1200 deg. C under inert atmosphere. The second way consisted in the precipitation of a precursor of TPD, identified as the Thorium Phosphate Hydrogen Phosphate loaded with the actinides considered. The gel initially formed by mixing concentrated phosphoric acid solution with the nitric actinide solution was heated at 90 - 160 deg. C in a closed PTFE container for several weeks. It led to the TPDAn solid solutions after heating at 1100 deg. C in air or under inert argon. The efficiency of both processes was evaluated through the determination of the decontamination for each actinide considered. Considering the encouraging results obtained for both kinds of processes, some complementary studies are now required before performing the effective decontamination of real Low-Level Liquid Waste using one of the methods proposed. (author) [fr

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  2. Rare Earth element (REE) incorporation in natural calcite. Upper limits for actinide uptake in a secondary phase

    International Nuclear Information System (INIS)

    Stipp, S.L.S.; Christensen, J.T.; Waight, T.E.; Lakshtanov, L.Z.; Baker, J.A.

    2006-01-01

    Secondary minerals have the potential to sequester escaped actinides in the event of a radioactive waste repository failure, but currently, data to define their maximum uptake capacity are generally lacking. To estimate a maximum limit for solid solution in calcite, we took advantage of the behavioural similarities of the 4f-orbital lanthanides with some of the 5f-orbital actinides and used rare Earth element (REE) concentration as an analogue. A suite of 65 calcite samples, mostly pure single crystals, was assembled from a range of geological settings, ages and locations and analysed by isotope dilution MC-ICP-MS (multiple-collector inductively-coupled plasma mass spectroscopy). All samples were shown to contain significant lanthanide concentrations. The highest were in calcite formed from hydrothermal solutions and from carbonatite magma. Maximum total mole fraction of REE was 4.72 x 10 -4 , which represents one substituted atom for about 2000 Ca sites. In comparison, synthetic calcite, precipitated at growth rates slow enough to insure solid solution formation, incorporated 7.5 x 10 -4 mole fraction Eu(III). For performance assessment, we propose that 7.5 mmole substitution/kg calcite should be considered the upper limit for actinide incorporation in secondary calcite. The largest source of uncertainty in this estimate results from extrapolating lanthanide data to actinides. However, the data offer confidence that for waters in the hydrothermal temperature range, such as in the near-field, or at groundwater temperatures, such as in the far-field, if calcite formation is favoured and actinides are present, those with behaviour like the trivalent lanthanides, especially Am 3+ and Cm 3+ , will be incorporated. REE are abundant and widely distributed, and they have remained in calcite for millions of years. Thus, one can be certain that incorporated actinides will also remain immobilised in calcite formed in fractures and pore spaces, as long as solution conditions

  3. Room temperature electrodeposition of actinides from ionic solutions

    Science.gov (United States)

    Hatchett, David W.; Czerwinski, Kenneth R.; Droessler, Janelle; Kinyanjui, John

    2017-04-25

    Uranic and transuranic metals and metal oxides are first dissolved in ozone compositions. The resulting solution in ozone can be further dissolved in ionic liquids to form a second solution. The metals in the second solution are then electrochemically deposited from the second solutions as room temperature ionic liquid (RTIL), tri-methyl-n-butyl ammonium n-bis(trifluoromethansulfonylimide) [Me.sub.3N.sup.nBu][TFSI] providing an alternative non-aqueous system for the extraction and reclamation of actinides from reprocessed fuel materials. Deposition of U metal is achieved using TFSI complexes of U(III) and U(IV) containing the anion common to the RTIL. TFSI complexes of uranium were produced to ensure solubility of the species in the ionic liquid. The methods provide a first measure of the thermodynamic properties of U metal deposition using Uranium complexes with different oxidation states from RTIL solution at room temperature.

  4. Sorption of Cs, I, and actinides in concrete systems

    International Nuclear Information System (INIS)

    Allard, B.; Eliasson, L.; Andersson, K.

    1984-09-01

    Samples of seven different concretes were prepared (Standard Portland cement of two kinds; sulphate resistant, blast furnace slag, high alumina, fly ash, and silica cements) and the corresponding pore waters were analyzed. Batch-wise distribution studies were performed in the various concrete/pore water systems, as well as for three old concrete samples from a hydro power station dam (more than 60 years old), for the elements Cs, I, Th, U, Np, Pu, and Am at trace concentration levels. Generally the sorption of Cs was low, and somewhat higher for I. All the actinides, including U and Np in their hexa- and pentavalent states, respectively, were strongly sorbed on the cement phase. (Author)

  5. Actinide partitioning-transmutation program final report. IV. Miscellaneous aspects

    International Nuclear Information System (INIS)

    Alexander, C.W.; Croff, A.G.

    1980-09-01

    This report discusses seven aspects of actinide partitioning-transmutation (P-T) which are important in any complete evaluation of this waste treatment option but which do not fall within other major topical areas concerning P-T. The so-called miscellaneous aspects considered are (1) the conceptual design of a shipping cask for highly neutron-active fresh and spent P-T fuels, (2) the possible impacts of P-T on mixed-oxide fuel fabrication, (3) alternatives for handling the existing and to-be-produced spent fuel and/or wastes until implementation of P-T, (4) the decay and dose characteristics of P-T and standard reactor fuels, (5) the implications of P-T on currently existing nuclear policy in the United States, (6) the summary costs of P-T, and (7) methods for comparing the risks, costs, and benefits of P-T

  6. Programme and Abstracts. 38. Journees des Actinides together with the 7. School on the Physics and Chemistry of the Actinides

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-01

    Journees des Actinides (JdA) is a traditional informal actinide forum, including physics, chemistry, and materials research. It regularly brings together experts from fields involved, taking place in a very informal way, emphasizing exchanges and discussions on current issues in actinide science. At the 38{sup th} JdA (10-15 April 2008; Wroclaw, Poland) scientific communications on the following topics on physics and chemistry of the actinides were presented: (a) inorganic and organometallic chemistry; (b) strongly correlated behaviour, superconductivity, quantum criticality; (c) materials science; (d) theory, electronic structure; (e) nuclear fuel cycle, environment.

  7. Programme and Abstracts. 38. Journees des Actinides together with the 7. School on the Physics and Chemistry of the Actinides

    International Nuclear Information System (INIS)

    2008-01-01

    Journees des Actinides (JdA) is a traditional informal actinide forum, including physics, chemistry, and materials research. It regularly brings together experts from fields involved, taking place in a very informal way, emphasizing exchanges and discussions on current issues in actinide science. At the 38 th JdA (10-15 April 2008; Wroclaw, Poland) scientific communications on the following topics on physics and chemistry of the actinides were presented: (a) inorganic and organometallic chemistry; (b) strongly correlated behaviour, superconductivity, quantum criticality; (c) materials science; (d) theory, electronic structure; (e) nuclear fuel cycle, environment

  8. Correlation of retention of lanthanide and actinide complexes with stability constants and their speciation

    Energy Technology Data Exchange (ETDEWEB)

    Datta, A.; Sivaraman, N.; Viswanathan, K.S.; Ghosh, Suddhasattwa; Srinivasan, T.G.; Vasudeva Rao, P.R. [Indira Gandhi Centre for Atomic Research, Kalpakkam (India). Chemistry Group

    2013-03-01

    The present study describes a correlation that is developed from retention of lanthanide and actinide complexes with the stability constant. In these studies, an ion-pairing reagent, camphor-10-sulphonic acid (CSA) was used as the modifier and organic acids such as {alpha}-hydroxy isobutyric acid ({alpha}-HIBA), mandelic acid, lactic acid and tartaric acid were used as complexing reagent for elution. From these studies, a correlation has been established between capacity factor of a metal ion, concentration of ion-pairing reagent and complexing agent with the stability constant of metal complex. Based on these studies, it has been shown that the stability constant of lanthanide and actinide complexes can be estimated using a single lanthanide calibrant. Validation of the method was carried out with the complexing agents such as {alpha}-HIBA and lactic acid. It was also demonstrated that data from a single chromatogram can be used for estimation of stability constant at various ionic strengths. These studies also demonstrated that the method can be applied for estimation of stability constant of actinides with a ligand whose value is not reported yet, e.g., ligands of importance in the lanthanide-actinide separations, chelation therapy etc. The chromatographic separation method is fast and the estimation of stability constant can be done in a very short time, which is a significant advantage especially in dealing with radioactive elements. The stability constant data was used to derive speciation data of plutonium in different oxidation states as well as that of americium with {alpha}-HIBA. The elution behavior of actinides such as Pu and Am from reversed phase chromatographic technique could be explained based on these studies. (orig.)

  9. New developments at the INE-Beamline for actinide research at ANKA

    Science.gov (United States)

    Dardenne, K.; Brendebach, B.; Denecke, M. A.; Liu, X.; Rothe, J.; Vitova, T.

    2009-11-01

    The INE-Beamline for actinide research at the synchrotron source ANKA is operated by the Institut für Nukleare Entsorgung (INE) at the Forschungszentrum Karlsruhe. Experiments on radioactive samples with activities up to 106 times the limit of exemption inside a safe and flexible double containment concept are possible. One great advantage of the beamline is its close proximity to INE's active laboratories with its equipment for manipulation of actinide materials and state-of-the-art spectroscopic, analytical, and microscopic instrumentation. This constellation is unique in Europe. The INE-Beamline is built primarily to serve INE in-house research associated with safe disposal of high level nuclear waste such as actinide speciation or coordination-, redox-, and geo-chemistry of actinides. A wide energy range from around 2.1 keV to 25 keV covering the K-edges from P to Pd and the L3, L2, and L1 edges for actinides from Th to Cm can be used. The INE-Beamline is optimized for X-ray absorption spectroscopy techniques (XANES/EXAFS), but x-ray fluorescence (XRF) analysis and powder diffraction (XRD) are also possible, as well as surface sensitive measurements in grazing incidence geometry (GI-XAFS). Upgrades of instrumentation and extension of experimental capabilities at the INE-Beamline are driven by user needs. Two of the recent upgrades are presented: 1) installation of a microfocus option for spatially resolved studies (μ-XRF, μ-XANES, μ-XRD) and investigations of small volumes (e.g., heterogeneous natural samples and diamond anvil high pressure cells); 2) construction, and commissioning of a high resolution x-ray emission spectrometer (HRXES); 3) availability of an electrochemical cell for investigation of redox sensitive systems.

  10. Synthesis and Evaluation of new Polyfunctional Molecules for Group Actinide Extraction

    International Nuclear Information System (INIS)

    Marie, C.

    2009-10-01

    The aim of this project is to design new extracting molecules for spent nuclear fuel reprocessing. In order to minimize the long-term residual radiotoxicity of the waste, the GANEX process is an option based on homogeneous recycling of actinides. All actinides (U, Np, Pu, Am, Cm), present in a highly acidic aqueous solution, would be extracted together and separated from fission products (especially from lanthanides) using liquid-liquid extraction. In this context, twenty new bi-topic ligands constituted of a nitrogen poly-aromatic unit functionalized by amide groups were synthesized. Liquid-liquid extraction tests with these ligands dissolved alone in the organic phase show that N, N, N', N'-tetra-alkyl-6, 6''(2, 2':6', 2''-terpyridine)-diamides are able to selectively extract actinides at different oxidation states (Np(V et VI), U(VI), Pu(IV), Am(III), Cm(III)) from an aqueous solution 3M HNO 3 . Nevertheless, actinides(III) are poorly extracted. According to crystallographic structures of complexes with Nd(III) and U(VI) determined by X-rays diffraction, these ligands are penta-dentate. In solution (methanol), complexes stoichiometries (1:1) of Nd(III), U(VI) and Pu(IV) were determined by electro-spray ionization mass spectrometry. Stability constants, evaluated by UV-visible spectrophotometry in MeOH/H 2 O solutions, confirm the selectivity of ligands toward actinides(III) with respect to lanthanides(III). Associate to nuclear magnetic resonance experiments and DFT calculations (Density Functional Theory), a better knowledge of their coordination mode was achieved. (author)

  11. Observations of multiple order parameters in 5f electron systems; Observations de parametres d'ordre multiples dans les systemes d'electrons 5f

    Energy Technology Data Exchange (ETDEWEB)

    Blackburn, E

    2005-12-15

    In this thesis, multiple order parameters originating in the same electronic system are studied. The multi-k magnetic structures, where more than one propagation wavevector, k, is observed in the same volume, are considered as prototypical models. The effect of this structure on the elastic and inelastic response is studied. In cubic 3-k uranium rock-salts, unexpected elastic diffraction events were observed at positions in reciprocal space where the structure factor should have been zero. These diffraction peaks are identified with correlations between the (orthogonal) magnetic order parameters. The 3-k structure also affects the observed dynamics; the spin-wave fluctuations in uranium dioxide as observed by inelastic neutron polarization analysis can only be explained on the basis of a 3-k structure. In the antiferromagnetic superconductor UPd{sub 2}Al{sub 3} the magnetic order and the super-conducting state coexist, and are apparently generated by the same heavy fermions. The effect of an external magnetic field on both the normal and superconducting states is examined. In the normal state, the compound displays Fermi-liquid-like behaviour. The inelastic neutron response is strongly renormalized on entering the superconducting state, and high-precision measurements of the low-energy transfer part of this response confirm that the superconducting energy gap has the same symmetry as the antiferromagnetic lattice. (author)

  12. Structural characterization of the Actinides (III) and (IV) - DOTA complexes

    International Nuclear Information System (INIS)

    Audras, Matthieu

    2014-01-01

    The polyamino-carboxylate anions have been identified as compounds of interest in the operations of actinide separation, in actinide migration in the environment and in human radio-toxicology. The structural characterization of complexes formed between actinides and polyamino-carboxylates ligands is essential for a better understanding of actinide-ligands interactions. Among the polyamino-carboxylate anions, the DOTA ligand (1,4,7,10-tetraaza-cyclododecane tetraacetic acid) is described as a very strong complexing agent of the lanthanides(III), but has been little studied with actinides. The objective of this thesis is to describe the complexes formed between the actinides (III) and (IV) and the DOTA ligand, and compare them with the lanthanide complexes. For this, an approach has been introduced to characterize the complexes by complementary analytical techniques (spectrophotometry, electro-spray ionization mass spectrometry, NMR, EXAFS, electrochemistry), but also by calculations of theoretical chemistry to help the interpretation of the experimental data. The formation of a 1:1 complex is observed with the actinides(III) (plutonium and americium) as for lanthanides(III): rapid formation of intermediate species which evolves slowly towards the formation of a limit complex. Within this complex, the cation is located inside the cavity formed by the ligand. Four nitrogen atoms and four oxygen atoms from the carboxylate functions are involved in the coordination sphere of the cation. However, differences were observed in the bond lengths formed between the cation and the nitrogen atoms (the bonds are somewhat shorter in the case of actinide complexes) as well as the complexation kinetics, which is slightly faster for the actinides(III) than for lanthanide(III) ions of equivalent radius. The same behavior was observed in solution upon complexation of actinides(IV) (uranium, plutonium and neptunium): slow formation of a 1:1 complex (actinide(IV):ligand) in wherein the

  13. Fundamental Thermodynamics of Actinide-Bearing Mineral Waste Forms

    International Nuclear Information System (INIS)

    Williamson, Mark A.; Ebbinghaus, Bartley B.; Navrotsky, Alexandria

    1999-01-01

    The recent arms reduction treaties between the U.S. and Russia have resulted in inventories of plutonium in excess of current defense needs. Storage of this material poses significant, and unnecessary, risks of diversion, especially for Russia whose infrastructure for protecting these materials has been weakened since the collapse of the Soviet Union. Moreover, maintaining and protecting these materials in their current form is costly. The United States has about sixty metric tons of excess plutonium, half of which is high-purity weapon material. This high purity material will be converted into mixed oxide (MOX) fuel for use in nuclear reactors. The less pure excess plutonium does not meet the specifications for MOX fuel and will not be purified to meet the fuel specifications. Instead, it will be immobilized directly in a ceramic. The ceramic will be encased in a high level waste (HLW) glass monolith (i.e., the can-in-canister option) thus making a form that simulates the intrinsic security of spent nuclear fuel. The immobilized product will be placed in a HLW repository. To meet the repository requirements, the product must be shown to be durable for the intended storage time, the host matrix must be stable in the radiation environment, the solubility and leaching characteristics of the plutonium in the host material must be established, and optimum processing parameters must be determined for the entire compositional envelope of feed materials. 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 forms proposed as immobilization matrices. However, the relevant thermodynamic data (e.g., enthalpy, entropy, and heat capacity) for the ceramic forms are severely lacking and this information gap directly affects the Energy Department's ability to license the disposal matrices and methods. High-temperature solution

  14. Contribution to the coordination chemistry of penta, hexa and heptavalent ions of 5f elements

    International Nuclear Information System (INIS)

    Musikas, Claude.

    1978-01-01

    This report has two main parts in which are discussed results dealing with: - aquo and hydroxo complexes of penta, hexa and heptavalent ions of 5f elements - pseuso halides complexes of these ions (SCN - , N 3 - , CN - ). It has been shown, by spectrophotometric and electrochemical measurements that U (V) possesses an aquo ion more acid than the known UO 2 + ion. This form is observed as insoluble hydroxid near pH 3.0 or as soluble polynuclear hydroxo complexes at lower pH. Hydroxo anionic complexes of U (VI) have been observed and one can precise the mecanism of hydrolysis of UO 2 ++ ions beyond he hydroxid UO 2 (OH) 2 . At pH 9 to 12, polynuclear species with low negative charge have been observed. At pH 13, others OH - ions enter in the coordination sphere of UO 2 ++ and mononuclear species are obtained. Reduction of polynuclear species leads to mixed hydroxo complexes of 'blue type'. Studies of hydrolysis of NpO 2 + allow to propose an hydrolysis mechanism similar to UO 2 ++ one. With electrochemical methods that in acidic media Np (VII) is present as NpO 3 + ions. Solubility product of NpO 3 OH has been measured. The second part is devoted to pseudohalides complexes of UO 2 ++ , UO 2 + and NpO 2 + ions [fr

  15. Oxidative Stress Type Influences the Properties of Antioxidants Containing Polyphenols in RINm5F Beta Cells

    Directory of Open Access Journals (Sweden)

    Nathalie Auberval

    2015-01-01

    Full Text Available The in vitro methods currently used to screen bioactive compounds focus on the use of a single model of oxidative stress. However, this simplistic view may lead to conflicting results. The aim of this study was to evaluate the antioxidant properties of two natural extracts (a mix of red wine polyphenols (RWPs and epigallocatechin gallate (EGCG with three models of oxidative stress induced with hydrogen peroxide (H2O2, a mixture of hypoxanthine and xanthine oxidase (HX/XO, or streptozotocin (STZ in RINm5F beta cells. We employed multiple approaches to validate their potential as therapeutic treatment options, including cell viability, reactive oxygen species production, and antioxidant enzymes expression. All three oxidative stresses induced a decrease in cell viability and an increase in apoptosis, whereas the level of ROS production was variable depending on the type of stress. The highest level of ROS was found for the HX/XO-induced stress, an increase that was reflected by higher expression antioxidant enzymes. Further, both antioxidant compounds presented beneficial effects during oxidative stress, but EGCG appeared to be a more efficient antioxidant. These data indicate that the efficiency of natural antioxidants is dependent on both the nature of the compound and the type of oxidative stress generated.

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

    Indian Academy of Sciences (India)

    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 ...

  17. Synergistic extraction of actinides : Part I. Hexa-and pentavalent actinides

    International Nuclear Information System (INIS)

    Patil, S.K.; Ramakrishna, V.V.

    1980-01-01

    A detailed discussion on the reported literature on the synergistic extraction of hexa- and pentavalent actinide ions, by different combinations of extractants and from different aqueous media, is presented. Structural aspects of the various complexes involved in synergism also are reviewed. A short account of the applications based on synergistic extraction is also given. (author)

  18. Research needs in metabolism and dosimetry of the actinides

    International Nuclear Information System (INIS)

    Richmond, C.R.

    1978-01-01

    The following topics are discussed: uranium mine and mill tailings; environmental standards; recommendations of NCRP and ICRP; metabolic models and health effects; life-time exposures to actinides and other alpha emitters; high-specific-activity actinide isotopes versus naturally occurring isotopic mixtures of uranium isotopes; adequacy of the n factor; and metabolism and dosimetry;

  19. ACTINET - EU network of excellence for actinide sciences

    International Nuclear Information System (INIS)

    Gompper, K.

    2006-01-01

    ACTINET, the Network of Excellence for Actinide Sciences within the 6th EU Framework Program, was launched in March 2004 for an initial period of four years. A number of tools are available in ACTINET to serve the purposes of the project, i.e. stimulate and coordinate actinide research in Europe, promote integration, train young scientists and, in this way, ensure and enhance European competence. The large European actinide laboratories with their unique experimental and analytical equipment are available to scientists from Europe as so-called 'pool facilities' within the framework of joint research projects. Setting up a 'theoretical user lab' has turned out to be a promising way of exploiting the synergies of theory and experiment in various fields of actinide science. Joint research projects are supported within the network, working with actinides being made possible in the pool facilities. Training and instruction are ensured by seminars, workshops, and schools organized annually. In familiarizing young scientists with actinide work, ACTINET exercises training functions and contributes to ensuring and enhancing European competence in the field on the medium and long term. Even after only half of its term, ACTINET is developing into a live network, thus decisively contributing towards promoting, coordinating and integrating European actinide research. As actinides play a key role in the use of nuclear power, this benefits European industries, research centers, operators of nuclear power plants and nuclear facilities as well as licensing and regulatory authorities. (orig.)

  20. Transmutation of minor actinide using thorium fueled BWR core

    International Nuclear Information System (INIS)

    Susilo, Jati

    2002-01-01

    One of the methods to conduct transmutation of minor actinide is the use of BWR with thorium fuel. Thorium fuel has a specific behaviour of producing a little secondary minor actinides. Transmutation of minor actinide is done by loading it in the BWR with thorium fuel through two methods, namely close recycle and accumulation recycle. The calculation of minor actinide composition produced, weigh of minor actinide transmuted, and percentage of reminder transmutation was carried SRAC. The calculations were done to equivalent cell modeling from one fuel rod of BWR. The results show that minor actinide transmutation is more effective using thorium fuel than uranium fuel, through both close recycle and accumulation recycle. Minor actinide transmutation weight show that the same value for those recycle for 5th recycle. And most of all minor actinide produced from 5 unit BWR uranium fuel can transmuted in the 6 t h of close recycle. And, the minimal value of excess reactivity of the core is 12,15 % Δk/k, that is possible value for core operation

  1. Actinide extractants for the nuclear industry of the future

    International Nuclear Information System (INIS)

    Musikas, C.; Morisseau, J.C.; Hoel, P.; Guillaume, B.

    1987-06-01

    Non organo-phosphorus extractants properties regarding the extractions of actinides in nuclear fuels reprocessing are presented. N,N-dialkylamides are proposed as alternatives to TBP.N,N'-tetraalkylamides or pentaalkyl propane diamides properties are reported. They show that those bidentate extractants are alternatives to bidentate organophosphorus extractants for actinides (III) extraction from concentrated nitric acid. 11 figs, 15 refs

  2. Separations chemistry for actinide elements: Recent developments and historical perspective

    International Nuclear Information System (INIS)

    Nash, K.L.; Choppin, G.R.

    1997-01-01

    With the end of the cold war, the principal mission in actinide separations has changed from production of plutonium to cleanup of the immense volume of moderately radioactive mixed wastes which resulted from fifty years of processing activities. In order to approach the cleanup task from a proper perspective, it is necessary to understand how the wastes were generated. Most of the key separations techniques central to actinide production were developed in the 40's and 50's for the identification and production of actinide elements. Total actinide recovery, lanthanide/actinide separations, and selective partitioning of actinides from inert constituents are currently of primary concern. To respond to the modern world of actinide separations, new techniques are being developed for separations ranging from analytical methods to detect ultra-trace concentrations (for bioassay and environmental monitoring) to large-scale waste treatment procedures. In this report, the history of actinide separations, both the basic science and production aspects, is examined and evaluated in terms of contemporary priorities

  3. Potential carcinogenic effects of actinides in the environment

    International Nuclear Information System (INIS)

    Harley, N.H.; Pasternack, B.S.

    1979-01-01

    Inhalation of alpha emitting actinides delivers a dose to critical cancer sites in the human body. These sites are the bronchial epithelium and cells near bone surfaces. Inhalation of the naturally occurring actinides uranium and thorium in resuspended soil in the air results in a continuous exposure for the global population of about 0.1 fCi/m 3 for each of these actinides. The highest dose is from the natural actinide 230 Th. Over 50 yr, the dose to bronchial epithelium is 0.05 mrad and to bone surfaces 0.4 mrad. In the case of accidental environmental contamination (e.g. near a nuclear fuel reprocessing plant) the man-made actinides plutonium, americium and curium could deliver about the same alpha dose to these sites if the soil is contaminated to the same level as the natural actinides (approximately 1 pCi/g). Two nuclear accidents have already produced contamination of about this level. Exposures in this case, however, are to small local populations compared with global exposure for the natural actinides. Significant enhancement of the natural radioactive actinide pollution by combustion of all types of fossil fuel is suspected but not enough data are available to estimate total population doses. (author)

  4. Solubility of actinides and surrogates in nuclear glasses

    International Nuclear Information System (INIS)

    Lopez, Ch.

    2003-01-01

    The nuclear wastes are currently incorporated in borosilicate glass matrices. The resulting glass must be perfectly homogeneous. The work discussed here is a study of actinide (thorium and plutonium) solubility in borosilicate glass, undertaken to assess the extent of actinide solubility in the glass and to understand the mechanisms controlling actinide solubilization. Glass specimens containing; actinide surrogates were used to prepare and optimize the fabrication of radioactive glass samples. These preliminary studies revealed that actinide Surrogates solubility in the glass was enhanced by controlling the processing temperature, the dissolution kinetic of the surrogate precursors, the glass composition and the oxidizing versus reducing conditions. The actinide solubility was investigated in the borosilicate glass. The evolution of thorium solubility in borosilicate glass was determined for temperatures ranging from 1200 deg C to 1400 deg C.Borosilicate glass specimens containing plutonium were fabricated. The experimental result showed that the plutonium solubility limit ranged from 1 to 2.5 wt% PuO 2 at 1200 deg C. A structural approach based on the determination of the local structure around actinides and their surrogates by EXAFS spectroscopy was used to determine their structural role in the glass and the nature of their bonding with the vitreous network. This approach revealed a correlation between the length of these bonds and the solubility of the actinides and their surrogates. (author)

  5. Advanced Extraction Methods for Actinide/Lanthanide Separations

    International Nuclear Information System (INIS)

    Scott, M.J.

    2005-01-01

    The separation of An(III) ions from chemically similar Ln(III) ions is perhaps one of the most difficult problems encountered during the processing of nuclear waste. In the 3+ oxidation states, the metal ions have an identical charge and roughly the same ionic radius. They differ strictly in the relative energies of their f- and d-orbitals, and to separate these metal ions, ligands will need to be developed that take advantage of this small but important distinction. The extraction of uranium and plutonium from nitric acid solution can be performed quantitatively by the extraction with the TBP (tributyl phosphate). Commercially, this process has found wide use in the PUREX (plutonium uranium extraction) reprocessing method. The TRUEX (transuranium extraction) process is further used to coextract the trivalent lanthanides and actinides ions from HLLW generated during PUREX extraction. This method uses CMPO [(N, N-diisobutylcarbamoylmethyl) octylphenylphosphineoxide] intermixed with TBP as a synergistic agent. However, the final separation of trivalent actinides from trivalent lanthanides still remains a challenging task. In TRUEX nitric acid solution, the Am(III) ion is coordinated by three CMPO molecules and three nitrate anions. Taking inspiration from this data and previous work with calix[4]arene systems, researchers on this project have developed a C3-symmetric tris-CMPO ligand system using a triphenoxymethane platform as a base. The triphenoxymethane ligand systems have many advantages for the preparation of complex ligand systems. The compounds are very easy to prepare. The steric and solubility properties can be tuned through an extreme range by the inclusion of different alkoxy and alkyl groups such as methyoxy, ethoxy, t-butoxy, methyl, octyl, t-pentyl, or even t-pentyl at the ortho- and para-positions of the aryl rings. The triphenoxymethane ligand system shows promise as an improved extractant for both tetravalent and trivalent actinide recoveries form

  6. Advanced Extraction Methods for Actinide/Lanthanide Separations

    Energy Technology Data Exchange (ETDEWEB)

    Scott, M.J.

    2005-12-01

    The separation of An(III) ions from chemically similar Ln(III) ions is perhaps one of the most difficult problems encountered during the processing of nuclear waste. In the 3+ oxidation states, the metal ions have an identical charge and roughly the same ionic radius. They differ strictly in the relative energies of their f- and d-orbitals, and to separate these metal ions, ligands will need to be developed that take advantage of this small but important distinction. The extraction of uranium and plutonium from nitric acid solution can be performed quantitatively by the extraction with the TBP (tributyl phosphate). Commercially, this process has found wide use in the PUREX (plutonium uranium extraction) reprocessing method. The TRUEX (transuranium extraction) process is further used to coextract the trivalent lanthanides and actinides ions from HLLW generated during PUREX extraction. This method uses CMPO [(N, N-diisobutylcarbamoylmethyl) octylphenylphosphineoxide] intermixed with TBP as a synergistic agent. However, the final separation of trivalent actinides from trivalent lanthanides still remains a challenging task. In TRUEX nitric acid solution, the Am(III) ion is coordinated by three CMPO molecules and three nitrate anions. Taking inspiration from this data and previous work with calix[4]arene systems, researchers on this project have developed a C3-symmetric tris-CMPO ligand system using a triphenoxymethane platform as a base. The triphenoxymethane ligand systems have many advantages for the preparation of complex ligand systems. The compounds are very easy to prepare. The steric and solubility properties can be tuned through an extreme range by the inclusion of different alkoxy and alkyl groups such as methyoxy, ethoxy, t-butoxy, methyl, octyl, t-pentyl, or even t-pentyl at the ortho- and para-positions of the aryl rings. The triphenoxymethane ligand system shows promise as an improved extractant for both tetravalent and trivalent actinide recoveries form

  7. β4 systematics in rare-earth and actinide nuclei: sdg interacting boson model description

    International Nuclear Information System (INIS)

    Devi, Y.D.; Kota, V.K.B.

    1992-01-01

    The observed variation of hexadecupole deformation parameter β 4 with mass number A in rare-earth and actinide nuclei is studied in the sdg interacting boson model (IBM) using single j-shell Otsuka-Arima-Iachello mapped and IBM-2 to IBM-1 projected hexadecupole transition operator together with SU sdg (3) and SU sdg (5) coherent states. The SU sdg (3) limit is found to provide a good description of data

  8. Determination of actinides using ICP-SFMS

    International Nuclear Information System (INIS)

    Nygren, Ulrika

    2006-01-01

    Interest in the determination of the actinides using ICP-MS has steadily increased with the development of systems capable of more sensitive and precise measurements. However, the analysis of less abundant actinides such as Pu and Am is not straightforward due to the need for chemical separation of these elements prior to determination. In many applications of mass-spectrometric actinide analysis, isotope ratio measurements are important, either for the analysis of the isotopic composition of, e.g., U or Pu in the sample, or for quantitative determinations using isotope dilution mass spectrometry. In order to achieve high precision and accuracy in an isotope ratio measurement, corrections for instrumentally induced systematic errors, e.g., due to dead-time and mass bias, need to be considered. In this thesis, different aspects of actinide analysis using ICP-SFMS have been addressed. In Papers I and III, separation procedures based on solid phase extraction for Pu, Am and U were developed and evaluated with respect to chemical yield and separation from elements causing spectral interferences. Applications of the analytical procedures developed comprised measurement of the 240 Pu/ 2 3 9Pu ratio in environmental reference materials, and age determination of Pu based on the 241 Pu/ 241 Am and 240 Pu/ 236 U ratios. In the application of different separation procedures for Pu, previously unidentified spectral interferences were discovered. In Paper II, these interferences were identified as lanthanide phosphate ions and the composition and formation of these species with respect to different instrumental parameters were further examined. Due to the importance of precise and accurate isotope ratio determination, a thorough investigation of the instrumental dead time of an ICP-SFMS system was performed. The dead time was evaluated via both isotope ratio and electronic measurements of the output from the detector amplifier. It was found that the overall uncertainty in ratio

  9. Photofissility of actinide nuclei at intermediate energies

    International Nuclear Information System (INIS)

    Deppman, A.; Tavares, O.A.P.; Duarte, S.B.; Oliveira, E.C. de; Arruda-Neto, J.D.T.; Pina, S.R. de; Likhachev, V.P.; Mesa, J.; Goncalves, M.

    2001-08-01

    We analyze the recent experimental data on photofissility for 237 Np, 238 U, and 232 Th at incident photon energies above 200 MeV. For this analysis, we developed a Monte carlo algorithm for the nuclear evaporation process in photonuclear reactions. This code is used in association with the multi-collisional model for the photon-induced intranuclear cascade process. Our results show a good quantitative and qualitative agreement with the experimental data. It is shown that the emission of protons and alpha particles at the evaporation stage is an important component for the non-saturation of the actinides photofissility up to, at least, 1GeV. (author)

  10. Thermal decomposition of lanthanide and actinide tetrafluorides

    International Nuclear Information System (INIS)

    Gibson, J.K.; Haire, R.G.

    1988-01-01

    The thermal stabilities of several lanthanide/actinide tetrafluorides have been studied using mass spectrometry to monitor the gaseous decomposition products, and powder X-ray diffraction (XRD) to identify solid products. The tetrafluorides, TbF 4 , CmF 4 , and AmF 4 , have been found to thermally decompose to their respective solid trifluorides with accompanying release of fluorine, while cerium tetrafluoride has been found to be significantly more thermally stable and to congruently sublime as CeF 4 prior to appreciable decomposition. The results of these studies are discussed in relation to other relevant experimental studies and the thermodynamics of the decomposition processes. 9 refs., 3 figs

  11. Fission cross section measurements for minor actinides

    Energy Technology Data Exchange (ETDEWEB)

    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)

  12. Status of nuclear data for actinides

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Compilation of actinide neutron nuclear data

    International Nuclear Information System (INIS)

    1979-01-01

    The Swedish nuclear data committee has compiled a selected set of neutron cross section data for the 16 most important actinide isotopes. The aim of the report is to present available data in a comprehensible way to allow a comparison between different evaluated libraries and to judge about the reliability of these libraries from the experimental data. The data are given in graphical form below about 1 ev and above about 10 keV shile the 2200 m/s cross sections and resonance integrals are given in numerical form. (G.B.)

  14. Thermodynamics of carbothermic synthesis of actinide mononitrides

    International Nuclear Information System (INIS)

    Ogawa, T.; Shirasu, Y.; Minato, K.; Serizawa, H.

    1997-01-01

    Carbothermic synthesis will be further applied to the fabrication of nitride fuels containing minor actinides (MA) such as neptunium, americium and curium. A thorough understanding of the carbothermic synthesis of UN will be beneficial in the development of the MA-containing fuels. Thermodynamic analysis was carried out for conditions of practical interest in order to better understand the recent fabrication experiences. Two types of solution phases, oxynitride and carbonitride phases, were taken into account. The Pu-N-O ternary isotherm was assessed for the modelling of M(C, N, O). With the understanding of the UN synthesis, the fabrication problems of Am-containing nitrides are discussed. (orig.)

  15. Impact of minor actinide recycling on sustainable fuel cycle options

    Energy Technology Data Exchange (ETDEWEB)

    Heidet, F.; Kim, T. K.; Taiwo, T. A.

    2017-11-01

    The recent Evaluation and Screening study chartered by the U.S. Department of Energy, Office of Nuclear Energy, has identified four fuel cycle options as being the most promising. Among these four options, the two single-stage fuel cycles rely on a fast reactor and are differing in the fact that in one case only uranium and plutonium are recycled while in the other case minor actinides are also recycled. The two other fuel cycles are two-stage and rely on both fast and thermal reactors. They also differ in the fact that in one case only uranium and plutonium are recycled while in the other case minor actinides are also recycled. The current study assesses the impact of recycling minor actinides on the reactor core design, its performance characteristics, and the characteristics of the recycled material and waste material. The recycling of minor actinides is found not to affect the reactor core performance, as long as the same cycle length, core layout and specific power are being used. One notable difference is that the required transuranics (TRU) content is slightly increased when minor actinides are recycled. The mass flows are mostly unchanged given a same specific power and cycle length. Although the material mass flows and reactor performance characteristics are hardly affected by recycling minor actinides, some differences are observed in the waste characteristics between the two fuel cycles considered. The absence of minor actinides in the waste results in a different buildup of decay products, and in somewhat different behaviors depending on the characteristic and time frame considered. Recycling of minor actinides is found to result in a reduction of the waste characteristics ranging from 10% to 90%. These results are consistent with previous studies in this domain and depending on the time frame considered, packaging conditions, repository site, repository strategy, the differences observed in the waste characteristics could be beneficial and help improve

  16. Actinide recovery from waste and low-grade sources

    International Nuclear Information System (INIS)

    Navratil, J.D.; Schulz, W.W.

    1982-01-01

    Actinide and nuclear fuel cycle operations generate a variety of process waste streams. New methods are needed to remove and recover actinides. More interest is also being expressed in recovering uranium from oceans, phosphoric acid, and other low grade sources. To meet the need for an up-to-date status report in the area of actinide recovery from waste and low grade sources, these papers were brought together. The papers provide an authoritative, in-depth coverage of an important area of nuclear and industrial and engineering chemistry which cover the following topics: uranium recovery from oceans and phosphoric acid; recovery of actinides from solids and liquid wastes; plutonium scrap recovery technology; and other new developments in actinide recovery processes

  17. The radiological impact of actinides discharged to the Irish Sea

    International Nuclear Information System (INIS)

    Hunt, G.J.; Smith, B.D.

    1999-01-01

    This paper describes the radiological effects of releases of actinides to the Irish Sea from Sellafield, the major source. Exposure pathways to man since the commencement of discharges in 1952 are reviewed; the importance of actinides began to increase with increased discharges in the 1970s. With the demise of the porphyra/laverbread pathway due to transport difficulties, the pathway due to fish and shellfish consumption became critical, particularly for actinides through molluscan shellfish. A reassessment on the current basis of effective dose shows that peak exposures to the critical group of about 2 mSv yr -1 were received in the mid-1970s, about 30% of which was due to actinides. Effective doses have since reduced but the relative importance of actinides is greater, due to the interplay of discharges of radionuclides from Sellafield and their behaviour in the environment. Additive doses through sea food due to releases of natural radionuclides from the Marchon phosphate plant at Whitehaven are also considered, although the actinide component from this source has been small. Exposures due to actinides from Sellafield via other pathways are shown to be much lower than those involving sea food. Collective doses are also considered; these peaked at about 300 man-Sv to the European population (including the UK) in 1979, with only a few percent due to actinides. As in the case of critical group doses, the relative importance of actinides has increased in recent years within the decreasing total collective dose. For both critical group and collective doses, therefore, the actinide component needs to be kept under review. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  18. The Thermodynamic Properties of the f-Elements and their Compounds. Part 2. The Lanthanide and Actinide Oxides

    Energy Technology Data Exchange (ETDEWEB)

    Konings, Rudy J. M., E-mail: rudy.konings@ec.europa.eu; Beneš, Ondrej; Kovács, Attila; Manara, Dario; Sedmidubský, David [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, 76125 Karlsruhe (Germany); Gorokhov, Lev; Iorish, Vladimir S.; Yungman, Vladimir; Shenyavskaya, E.; Osina, E. [Joint Institute for High Temperatures, Russian Academy of Sciences, 13-2 Izhorskaya Street, Moscow 125412 (Russian Federation)

    2014-03-15

    A comprehensive review of the thermodynamic properties of the oxide compounds of the lanthanide and actinide elements is presented. The available literature data for the solid, liquid, and gaseous state have been analysed and recommended values are presented. In case experimental data are missing, estimates have been made based on the trends in the two series, which are extensively discussed.

  19. Interactions of Microbes found at Aespoe Underground Lab with Actinides such as Curium, Plutonium and Uranium

    Energy Technology Data Exchange (ETDEWEB)

    Moll, H.; Merroun, M.; Geipel, G.; Rossberg, A.; Hennig, C.; Selenska-Pobell , S.; Bernhard, G. [Forschungszentrum Dresden-Rossendorf e.V., Inst. fuer Radioc hemie, 01314 Dresden (Germany)]. e-mail: h.moll@fzd.de; Stumpf, Th. [Forschungszentru m Karlsruhe, Inst. fuer Nukleare Entsorgung, 76021 Karlsruhe (Germany)

    2007-06-15

    Sulfate-reducing bacteria (SRB) frequently occur in the deep granitic rock aquifers at the Aespoe Hard Rock Laboratory (Aespoe HRL), Sweden. The new SRB strain Desulfovibrio aespoeensis could be isolated. Results describing the basic interaction mechanisms of uranium, curium, and plutonium with cells of D. aespoeensis DSM 10631T will be presented. The interaction experiments with the actinides showed that the cells are able to remove all three actinides from the surrounding solution. The amount of removed actinide and the interaction mechanism varied among the different actinides. The main U(VI) removal occurred after the first 24 h. The contact time, pH and [U(VI)]initial influence the U removal efficiency. The presence of uranium caused a damaging of the cell membranes. TEM revealed an accumulation of U inside the bacterial cell. D. aespoeensis are able to form U(IV). A complex interaction mechanism takes place consisting of biosorption, bioreduction and bioaccumulation. In the case of {sup 242}Pu, solvent extractions, UV-vis- and XANES spectroscopy were used to determine the speciation of the Pu oxidation states. In the first step, the Pu(VI) and Pu(IV)-polymers are bound to the biomass. Solvent extractions showed that 97 % of the initially present Pu(VI) is reduced to Pu(V) due to the activity of the cells within the first 24 h. Most of the formed Pu(V) dissolves from the cell envelope back to the aqueous solution due to the weak complexing properties of this plutonium oxidation state. In the case of curium at a much lower metal concentration of 3x10{sup -7} M, a pure biosorption of Cm(III) on the cell envelope forming an inner-sphere surface complex most likely with organic phosphate groups was detected. To summarize, the strength of the interaction of D. aespoeensis with the selected actinides at pH 5 and actinide concentrations = 10 mg/L ([Cm] 0.07 mg/L) follows the pattern: Cm > U > Pu >> Np.

  20. Recycle of LWR actinides to an IFR

    International Nuclear Information System (INIS)

    Pierce, R.D.; Ackerman, J.P.; Johnson, G.K.; Mulcahey, T.P.; Poa, D.S.

    1991-01-01

    Large quantities of actinide elements are present in irradiated light water reactor fuel that is stored throughout the world. Because of the high fission to capture ratio for the transuranium (TRU) elements with the high energy neutrons in metal-fueled integral fast reactors (IFR), that reactor can consume these elements effectively. The stored fuel may represent valuable resource for the expanding application of fast power reactors. In addition, the removal of TRU elements from spent LWR fuel has the potential for increasing the capacity of high level waste facilities by reducing the heat load and may increase the margin of safety in meeting licensing requirement. Argonne National Laboratory is developing a pyrochemical process, which is compatible with the IFR fuel cycle for the recovery of TRU elements from LWR fuel. The proposed product is a metallic actinide ingot, which can be introduced into the electrorefining step of the IFR process. Two pyrochemical processes, that is, salt transport process and blanket processing study, are discussed in this paper. Also the experimental studies are reported. (K.I.)

  1. Subcritical limits for special fissile actinides

    International Nuclear Information System (INIS)

    Clark, H.K.

    1980-01-01

    Critical masses and subcritical mass limits in oxide-water mixtures were calculated for actinide nuclides other than 233 U, 235 U, and 239 Pu that have an odd number of neutrons in the nucleus: S/sub n/ transport theory was used together with cross sections, drawn from the GLASS multigroup library, developed to provide accurate forecasts of actinide production at Savannah River. The subcritical limits are 201 g for 241 Pu, 13 g for 242 /sup m/Am, 90 g for 243 Cm, 30 g for 245 Cm, 900 g for 247 Cm, 10 g for 249 Cf, and 5 g for 251 Cf. Association of 241 Pu with an equal mass of 240 Pu increases the 241 Pu limit to a value greater than that for pure 239 Pu. Association of 242 /sup m/Am with 241 Am increases the limit for the mixture to that for dry, theoretical density AmO 2 at isotopic concentrations of 242 /sup m/Am less than approx. 6%. Association of 245 Cm with 244 Cm increases the limit according to the formula 30 + 0.3 244 Cm/ 245 Cm up to the limit for dry CmO 2 . A limiting mass of 8.15 kg for plutonium containing at least 67% 238 Pu as oxide was calculated that applies (provided 240 Pu exceeds 241 Pu) with no limit on moderation. 1 figure, 5 tables

  2. The dose from actinides in the environment

    International Nuclear Information System (INIS)

    Harley, Naomi H.; Pasternack, Bernard S.

    1978-01-01

    We attempt to evaluate the health effects on local populations from the nuclear power industry. The nuclides which are thought to be most hazardous are the long-lived, alpha-emitting isotopes of plutonium, americium and curium. These long-lived alpha emitters will almost certainly be dispersed in the environment during fuel reprocessing. Their effect is local, not global and at worst a single community could be affected. The most important pathway for exposure to the actinides is through inhalation following resuspension of contaminated soil particles. The most important alpha dose estimates are to cells in bronchial epithelium and cells on bone surfaces. These alpha dose estimates are calculated for a dispersal which contaminates soil with 1 pCi/g of each of the nuclides Pu 238,239 , Am 241 , Cm 242,244 . These bronchial and bone cell dose estimates are compared with those from the naturally occurring actinide 232 Th (and daughters) which are normally found in soil at a level of about 1 pCi/g. (author)

  3. Consistent biokinetic models for the actinide elements

    International Nuclear Information System (INIS)

    Leggett, R.W.

    2001-01-01

    The biokinetic models for Th, Np, Pu, Am and Cm currently recommended by the International Commission on Radiological Protection (ICRP) were developed within a generic framework that depicts gradual burial of skeletal activity in bone volume, depicts recycling of activity released to blood and links excretion to retention and translocation of activity. For other actinide elements such as Ac, Pa, Bk, Cf and Es, the ICRP still uses simplistic retention models that assign all skeletal activity to bone surface and depicts one-directional flow of activity from blood to long-term depositories to excreta. This mixture of updated and older models in ICRP documents has led to inconsistencies in dose estimates and interpretation of bioassay for radionuclides with reasonably similar biokinetics. This paper proposes new biokinetic models for Ac, Pa, Bk, Cf and Es that are consistent with the updated models for Th, Np, Pu, Am and Cm. The proposed models are developed within the ICRP's generic model framework for bone-surface-seeking radionuclides, and an effort has been made to develop parameter values that are consistent with results of comparative biokinetic data on the different actinide elements. (author)

  4. Actinides and rare earths complexation with adenosine phosphate nucleotides

    International Nuclear Information System (INIS)

    Mostapha, Sarah

    2013-01-01

    demonstrated that the dominant interaction is between the cations and the phosphate groups of the ligands. Complexes with monophosphate ligands (AMP-Lu, Lu-Th-AEP and AMP) show similar organizations with bridging phosphates indicating that the organic part does not have a significant effect on their structure. ADP and ATP solid state complexes (with two spheroid metal ions: Lu and Th) show several similarities in terms of local environment indicating that the occurrence of a third phosphate group has no significant effect on the local organization of the complex. However, despite the theoretical approaches that have been conducted, the right structure of these complexes has not been accurately determined. Complexes of lanthanides and actinide(III) (Am) with ATP behave similarly at macroscopic level suggesting an identical structure at the molecular level for these complexes. With uranyl, U-AMP complex synthesized at acidic pH show different behaviour at molecular level than that observed at alkaline pH but the same coordination sites (phosphates and hydroxyls ribose groups) have been demonstrated for both complexes. (author) [fr

  5. Burning minor actinides in a HTR energy spectrum

    International Nuclear Information System (INIS)

    Pohl, Christoph; Rütten, H. Jochem

    2012-01-01

    Highlights: ► Burn-up analysis for varying plutonium/minor actinide fuel compositions. ► The influence of varying heavy metal fuel element loads is investigated. ► Significant burn-up via radiative capture and subsequently fission is observed. ► Difference observed between fuel element burn-up and total actinide burning rate. - Abstract: The generation of nuclear energy by means of the existing nuclear reactor systems is based mainly on the fission of U-235. But this comes along with the capture of neutrons by the U-238 faction and results in a build-up of plutonium isotopes and minor actinides as neptunium, americium and curium. These actinides are dominant for the long time assessment of the radiological risk of a final disposal therefore a minimization of the long living isotopes is aspired. Burning the actinides in a high temperature helium cooled graphite moderated reactor (HTR) is one of these options. The use of plutonium isotopes to sustain the criticality of the system is intended to avoid on the one hand highly enriched uranium because of international regulations and on the other hand low enriched uranium because of the build up of new actinides from neutron capture in the U-238 fraction. Because initial minor actinide isotopes are typically not fissionable by thermal neutrons the idea is to fission instead the intermediate isotopes generated by the first neutron capture. This paper comprises calculations for plutonium/minor actinides/thorium fuel compositions and their correlated final burn-up for a generic pebble bed HTR based on the reference design of the 400 MW PBMR. In particular the cross sections and the neutron balance of the different minor actinide isotopes in the higher thermal energy spectrum of a HTR will be discussed. For a fuel mixture of plutonium and minor actinides a significant burn-up of these actinides up to 20% can be achieved but at the expense of a higher residual fraction of plutonium in the burned fuel. Combining

  6. New insights into phosphate based materials for the immobilisation of actinides

    Energy Technology Data Exchange (ETDEWEB)

    Neumeier, Stefan; Ji, Yaqi; Kowalski, Piotr M.; Kegler, Philip; Schlenz, Hartmut; Bosbach, Dirk; Deissmann, Guido [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Energie und Klimaforschung (IEK), Nukleare Entsorgung und Reaktorsicherheit (IEK-6); JARA High-Performance Computing, Aachen (Germany); Arinicheva, Yulia [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Energie und Klimaforschung (IEK), Nukleare Entsorgung und Reaktorsicherheit (IEK-6); JARA High-Performance Computing, Aachen (Germany); Forschungszentrum Juelich (Germany). Institut fuer Energie- und Klimaforschung (IEK), Werkstoffsynthese und Herstellungsverfahren (IEK-1); Heuser, Julia M. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Energie und Klimaforschung (IEK), Nukleare Entsorgung und Reaktorsicherheit (IEK-6); JARA High-Performance Computing, Aachen (Germany); Karlsruhe Institute of Technology (Germany). Inst. of Applied Materials (IAM)

    2017-07-01

    This paper focuses on major phosphate-based ceramic materials relevant for the immobilisation of Pu, minor actinides, fission and activation products. Key points addressed include the recent progress regarding synthesis methods, the formation of solid solutions by structural incorporation of actinides or their non-radioactive surrogates and waste form fabrication by advanced sintering techniques. Particular attention is paid to the properties that govern the long-term stability of the waste forms under conditions relevant to geological disposal. The paper highlights the benefits gained from synergies of state-of-the-art experimental approaches and advanced atomistic modeling tools for addressing properties and stability of f-element-bearing phosphate materials. In conclusion, this article provides a perspective on the recent advancements in the understanding of phosphate based ceramics and their properties with respect to their application as nuclear waste forms.

  7. Core Power Limits For A Lead-Bismuth Natural Circulation Actinide Burner Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Cliff Bybee; Kim, D.; Todreas, N. E.; Mujid S. Kazimi

    2002-04-01

    The Idaho National Engineering and Environmental Laboratory and Massachusetts Institute of Technology are investigating the suitability of lead-bismuth cooled fast reactors for producing low-cost electricity as well as for actinide burning. The design being considered here is a pool type reactor that burns actinides and utilizes natural circulation of the primary coolant, a conventional steam power conversion cycle, and a passive decay heat removal system. Thermal-hydraulic evaluations of the actinide burner reactor were performed to determine allowable core power ratings that maintain cladding temperatures below corrosion-established temperature limits during normal operation and following a loss-of-feedwater transient. An economic evaluation was performed to optimize various design parameters by minimizing capital cost. The transient power limit was initially much more restrictive than the steady-state limit. However, enhancements to the reactor vessel auxiliary cooling system for transient decay heat removal resulted in an increased power limit of 1040 MWt, which was close to the steady-state limit. An economic evaluation was performed to estimate the capital cost of the reactor and its sensitivity to the transient power limit. For the 1040 MWt power level, the capital cost estimate was 49 mills per kWhe based on 1999 dollars.

  8. End point control of an actinide precipitation reactor

    International Nuclear Information System (INIS)

    Muske, K.R.

    1997-01-01

    The actinide precipitation reactors in the nuclear materials processing facility at Los Alamos National Laboratory are used to remove actinides and other heavy metals from the effluent streams generated during the purification of plutonium. These effluent streams consist of hydrochloric acid solutions, ranging from one to five molar in concentration, in which actinides and other metals are dissolved. The actinides present are plutonium and americium. Typical actinide loadings range from one to five grams per liter. The most prevalent heavy metals are iron, chromium, and nickel that are due to stainless steel. Removal of these metals from solution is accomplished by hydroxide precipitation during the neutralization of the effluent. An end point control algorithm for the semi-batch actinide precipitation reactors at Los Alamos National Laboratory is described. The algorithm is based on an equilibrium solubility model of the chemical species in solution. This model is used to predict the amount of base hydroxide necessary to reach the end point of the actinide precipitation reaction. The model parameters are updated by on-line pH measurements

  9. Field studies on the terrestrial behavior of actinide elements in East Tennessee

    International Nuclear Information System (INIS)

    Garten, C.T. Jr.; Bondietti, E.A.; Trabalka, J.R.; Walker, R.L.; Scott, T.G.

    1984-01-01

    Field studies on the comparative uptake of various actinide elements ( 232 Th, 233 U, 238 U, 239 Pu, 241 Am, and 244 Cm) by plants and animals inhabiting historically contaminated environments on the Oak Ridge National Laboratory (ORNL) reservation in East Tennessee are summarized. The present-day pattern of actinide element bioaccumulation from a flood plain site contaminated with Pu in 1944 is U > Th approx. Pu. Thus the environmentally dispersed 239 Pu exhibits a transfer from floodplain soil to biota comparable to that of indigenous 232 Th and less than that of the indigenous 238 U. This ranking agrees with the chemical extractability of U, Th, and Pu from soil, using either weak acids or strongly basic reagents. The pattern of actinide element uptake from the shoreline of a historically contaminated pond is Pu 238 U = 233 U. This ranking also agrees with the chemical extractability of Pu, Am, Cm, and U from shoreline sediment, using weak acids. Results from field studies at ORNL agree with what has been generally inferred about the relative food chain transfer of the actinides, based on laboratory studies and field studies at other sites in the United States. Because they share the same valence state, there are apparent strong similarities in soil sorption, plant uptake, and animal uptake between trivalent Am and Cm and between tetravalent Pu and Th. Available evidence suggests that knowledge of the behavior of naturally occurring 232 Th in the terrestrial food chain can be useful for predicting the long-term fate of environmentally dispersed 239 Pu, while data on 238 U might be used to place an upper limit on the expected long-term food chain transfer of all transuranic elements except Np. 33 references, 5 figures, 1 table

  10. 49 CFR Appendix A to Part 591 - Section 591.5(f) Bond for the Entry of a Single Vehicle

    Science.gov (United States)

    2010-10-01

    ... VEHICLES AND EQUIPMENT SUBJECT TO FEDERAL SAFETY, BUMPER AND THEFT PREVENTION STANDARDS Pt. 591, App. A Appendix A to Part 591—Section 591.5(f) Bond for the Entry of a Single Vehicle Department of Transportation... Vehicle A Appendix A to Part 591 Transportation Other Regulations Relating to Transportation (Continued...

  11. Conception, synthesis and application of tripodands in actinide/lanthanide separation

    International Nuclear Information System (INIS)

    Bobet, Josselin

    1997-01-01

    The purpose of this work is the synthesis of C, H, O and N containing compounds able to separate '4f' and '5f' elements by liquid/liquid extraction. In a first part, the literature's study allow us to point out actinide and lanthanide ions actual nature and the different ways offered by organic chemistry to share two metallic ions between two liquid phases. On one hand, these trivalent cations' high coordination numbers drive us to synthesize tripodands with hard sites which were fitted for complexation. On the other hand, it appeared that carboxylate or even less-hard site like pyridine chelate selectively actinides, allowing separation. In a second part, 60 ligands were synthesized. In each of the ligands families, a structural parameter changes (site nature, distance between two neighbouring sites, sites respective orientation, lipophilicity and rigidity). 2,2-dihydroxymethyl-dodecanol and 1,3,5- tri(chlorocarbonyl) benzene were chosen as core. O-alkylation and amidation reactions were also peculiarly studied. Rekker's proceeding for lipophilicity calculation was used in order to establish a structure-activity relationship. In a third part, extraction assays with radioactive effluents ( 152 Eu and 241 Am) point out extraction and separation abilities of our compounds. Different operating ways were used according as ligand is soluble in aqueous or organic phase. Organic phase-soluble compounds were compared to DcH18C6, pyridine ones to 2,4,6-tri(2-pyridyl)-l,3,5-triazine (TPTZ) and carboxylate ones to diethylenetriamine-tetracetic acid (DTPA, Talspeak proceeding). The third phase phenomenon was encountered and studied. Influence of salt, pH and organic phase were also studied. (author) [fr

  12. Process for denitrating waste solutions containing nitrates and actinides with simultaneous separation of the actinides

    International Nuclear Information System (INIS)

    Gompper, K.

    1986-01-01

    The invention is intended to reduce the acid and nitrate content of nitrate waste solutions, to reduce the total salt content of the waste solution, to remove the actinides contained in it by precipitation, without any danger of violent reactions or an increase in the volume of the waste solution. The invention achieves this by mixing the waste solution with diethyl oxalate at room temperature and heating the mixture to at least 80 0 C. (orig./PW) [de

  13. Systematic studies of the energy levels of odd z even mass actinides

    International Nuclear Information System (INIS)

    Sood, P.C.

    1985-01-01

    The bandhead energies for the two-particle states in doubly odd actinides are evaluated based on the calculation of the zero-range residual interaction energy contribution. Guidelines are presented to decide the relative ordering of the expected configurations, leading to spin-parity assignments to the ground states and to the isomeric states in these nuclei. Presently available experimental information lists definite spin-parity for only four out of over fifty known nuclides in the region. Expected location of several new isomers, particularly in heavier nuclei, is indicated

  14. General survey of applications which require actinide nuclear data

    International Nuclear Information System (INIS)

    Raman, S.

    1976-01-01

    This review paper discusses the actinide waste problem, the buildup of toxic isotopes in the fuel, the neutron activity associated with irradiated fuel, the 252 Cf buildup problem, and the production of radioisotope power sources as broad areas that require actinide cross-section data. Decay data enter into the area of radiological safety and health physics. This paper also discusses a few cross-section measurements in progress at the Oak Ridge Electron Linear Accelerator. The availability of actinide samples through the Transuranium Program at Oak Ridge is discussed in considerable detail. The present data status with respect to the various applications is reviewed along with recommendations for improving the data base

  15. Review of actinide nitride properties with focus on safety aspects

    Energy Technology Data Exchange (ETDEWEB)

    Albiol, Thierry [CEA Cadarache, St Paul Lez Durance Cedex (France); Arai, Yasuo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-12-01

    This report provides a review of the potential advantages of using actinide nitrides as fuels and/or targets for nuclear waste transmutation. Then a summary of available properties of actinide nitrides is given. Results from irradiation experiments are reviewed and safety relevant aspects of nitride fuels are discussed, including design basis accidents (transients) and severe (core disruptive) accidents. Anyway, as rather few safety studies are currently available and as many basic physical data are still missing for some actinide nitrides, complementary studies are proposed. (author)

  16. Minor Actinide Laboratory at JRC-ITU: Fuel fabrication facility

    International Nuclear Information System (INIS)

    Fernandez, A.; McGinley, J.; Somers, J.

    2008-01-01

    The Minor Actinide Laboratory (MA-lab) of the Institute for Transuranium Elements is a unique facility for the fabrication of fuels and targets containing minor actinides (MA). It is of key importance for research on Partitioning and Transmutation in Europe, as it is one of the only dedicated facilities for the fabrication of MA containing materials, either for property measurements or for the production of test pins for irradiation experiments. In this paper a detailed description of the MA-Lab facility and the fabrication processes developed to fabricate fuels and samples containing high content of minor actinides is given. In addition, experience gained and improvements are also outlined. (authors)

  17. Status report on actinide and fission product transmutation studies

    International Nuclear Information System (INIS)

    1997-06-01

    The management of radioactive waste is one of the key issues in today's political and public discussions on nuclear energy. One of the fields that looks into the future possibilities of nuclear technology is the neutronic transmutation of actinides and of some most important fission products. Studies on transmutation of actinides are carried out in various countries and at an international level. This status report which gives an up-to-date general overview of current and planned research on transmutation of actinides and fission products in non-OECD countries, has been prepared by a Technical Committee meeting organized by the IAEA in September 1995. 168 refs, 16 figs, 34 tabs

  18. Report of the panel on practical problems in actinide biology

    International Nuclear Information System (INIS)

    Anon.

    1978-01-01

    Practical problems are classified as the need to make operational decisions, the need for regulatory assessment either of individual facilities or of generic actions, and the overt appearance of radiobiological effects in man or radioactivity in man or the environment. Topics discussed are as follows: simulated reactor accident; long term effects of low doses; effects of repeated exposures to actinides; inhaled uranium mine air contaminants; metabolism and dosimetry; environmental equilibrium models; patterns of alpha dosimetry; internal dose calculations; interfaces between actinide biology and environmental studies; removal of actinides deposited in the body; and research needs related to uranium isotopes

  19. Critical masses for the even-neutron-numbered transuranium actinides

    International Nuclear Information System (INIS)

    Westfall, R.M.

    1981-01-01

    As part of a standards effort of the American Nuclear Society to establish subcritical mass limits for the transuranium actinides, critical masses were calculated for seven actinides, critical masses were calculated for seven actinide elements in bare, water-reflected, and steel-reflected metal systems. For the nuclides /sup 242/Pu and /sup 241/Am, values obtained with ENDF/B-V cross-section data were in much better agreement with values inferred from experimental measurement than were initial values calculated with ENDF/B-IV data. A brief description of the analytical methods employed is followed by a presentation of the results. 10 refs

  20. Actinide and Xenon reactivity effects in ATW high flux systems

    International Nuclear Information System (INIS)

    Woosley, M.; Olson, K.; Henderson, D.L.

    1995-01-01

    In this paper, initial system reactivity response to flux changes caused by the actinides and xenon are investigated separately for a high flux ATW system. The maximum change in reactivity after a flux change due to the effect of the changing quantities of actinides is generally at least two orders of magnitude smaller than either the positive or negative reactivity effect associated with xenon after a shutdown or start-up. In any transient flux event, the reactivity response of the system to xenon will generally occlude the response due to the actinides

  1. Actinide and xenon reactivity effects in ATW high flux systems

    International Nuclear Information System (INIS)

    Woosley, M.; Olson, K.; Henderson, D. L.; Sailor, W. C.

    1995-01-01

    In this paper, initial system reactivity response to flux changes caused by the actinides and xenon are investigated separately for a high flux ATW system. The maximum change in reactivity after a flux change due to the effect of the changing quantities of actinides is generally at least two orders of magnitude smaller than either the positive or negative reactivity effect associated with xenon after a shutdown or start-up. In any transient flux event, the reactivity response of the system to xenon will generally occlude the response due to the actinides

  2. Actinide and Xenon reactivity effects in ATW high flux systems

    Energy Technology Data Exchange (ETDEWEB)

    Woosley, M. [Univ. of Virginia, Charlottesville, VA (United States); Olson, K.; Henderson, D.L. [Univ. of Wisconsin, Madison, WI (United States)] [and others

    1995-10-01

    In this paper, initial system reactivity response to flux changes caused by the actinides and xenon are investigated separately for a high flux ATW system. The maximum change in reactivity after a flux change due to the effect of the changing quantities of actinides is generally at least two orders of magnitude smaller than either the positive or negative reactivity effect associated with xenon after a shutdown or start-up. In any transient flux event, the reactivity response of the system to xenon will generally occlude the response due to the actinides.

  3. Effects of micro-water on decomposition of the environment-friendly insulating medium C5F10O

    Directory of Open Access Journals (Sweden)

    Song Xiao

    2017-06-01

    Full Text Available SF6 is widely used in all kinds of high-voltage electrical equipment because of its excellent insulation and arc-extinguishing performance. However, this compound leads to serious greenhouse effect, which harms the environment. Many research institutions are now actively in search of SF6 alternative gas. C5F10O has attracted much attention as an alternative gas with low global warming potential (GWP and excellent dielectric strength. In this paper, we analyzed the possible decomposition paths of C5F10O under micro-water environment through density functional theory. We also evaluated the ionization parameters and toxicity of the decomposition products. The results show that OH• and H• produced by H2O exhibited a catalytic effect on the decomposition of C5F10O. CF4, C2F6, C3F6, C3F8, C4F10, C5F12, C6F14, C3F7COH, C3F7OH, CF3COH, C3F7H, and CF3OH were produced in the micro-water environment. Based on molecular configuration calculation, the ionization parameters of these products were inferior to perfluorocarbons, such as C3F8, leading to reduced insulation performance of the system. Moreover, CF2O and HF are hazardous to human health and equipment safety. Results will provide a basis for further study of the insulation characteristic of the C5F10O gas mixture under micro-water condition to guide the formulation of their relevant international standards prior to engineering applications.

  4. Effects of micro-water on decomposition of the environment-friendly insulating medium C5F10O

    Science.gov (United States)

    Xiao, Song; Li, Yi; Zhang, Xiaoxing; Tian, Shuangshuang; Deng, Zaitao; Tang, Ju

    2017-06-01

    SF6 is widely used in all kinds of high-voltage electrical equipment because of its excellent insulation and arc-extinguishing performance. However, this compound leads to serious greenhouse effect, which harms the environment. Many research institutions are now actively in search of SF6 alternative gas. C5F10O has attracted much attention as an alternative gas with low global warming potential (GWP) and excellent dielectric strength. In this paper, we analyzed the possible decomposition paths of C5F10O under micro-water environment through density functional theory. We also evaluated the ionization parameters and toxicity of the decomposition products. The results show that OH• and H• produced by H2O exhibited a catalytic effect on the decomposition of C5F10O. CF4, C2F6, C3F6, C3F8, C4F10, C5F12, C6F14, C3F7COH, C3F7OH, CF3COH, C3F7H, and CF3OH were produced in the micro-water environment. Based on molecular configuration calculation, the ionization parameters of these products were inferior to perfluorocarbons, such as C3F8, leading to reduced insulation performance of the system. Moreover, CF2O and HF are hazardous to human health and equipment safety. Results will provide a basis for further study of the insulation characteristic of the C5F10O gas mixture under micro-water condition to guide the formulation of their relevant international standards prior to engineering applications.

  5. Investigating actinide compounds within a hybrid MCSCF-DFT model

    International Nuclear Information System (INIS)

    Fromager, E.; Jensen, H.J.A.; Wahlin, P.; Real, F.; Wahlgren, U.

    2007-01-01

    Complete text of publication follows: Investigations of actinide chemistry with quantum chemical methods still remain a complicated task since it requires an accurate and efficient treatment of the environment (crystal or solvent) as well as relativistic and electron correlation effects. Concerning the latter, the current correlated methods, based on either Density-Functional Theory (DFT) or Wave-Function Theory (WFT), have their advantages and drawbacks. On the one hand, Kohn-Sham DFT (KS-DFT) calculates the dynamic correlation quite accurately and at a fairly low computational cost. However, it does not treat adequately the static correlation, which is significant in some actinide compounds because of the near-degeneracy of the 5f orbitals: a first example is the bent geometry obtained in KS-DFT(B3LYP) for the neptunyl ion NpO 2 3+ , which is found to be linear within a Multi-Configurational Self-Consistent Field (MCSCF) model [1]. A second one is the stable and bent geometry obtained in KS-DFT(B3LYP) for the plutonyl ion PuO 2 4+ , which disintegrates at the MCSCF level [1]. On the other hand, WFT can describe the static correlation, using for example a MCSCF model, but then an important part of the dynamic correlation has to be neglected. This can be recovered with perturbation-theory based methods like for example CASPT2 or NEVPT2, but their computational complexity prevents large scale calculations. It is therefore of great interest to develop a hybrid MCSCF-DFT model which combines the best of both WFT and DFT approaches. The merge of WFT and DFT can be achieved by splitting the two-electron interaction into long-range and short-range parts [2]. The long-range part is then treated by WFT and the short-range part by DFT. We use the so-called 'erf' long-range interaction erf(μr 12 )/r 12 , which is based on the standard error function, and where μ is a free parameter which controls the long/short-range decomposition. The newly proposed recipe for the

  6. Fission properties of very heavy actinides

    International Nuclear Information System (INIS)

    Hoffman, D.C.

    1979-01-01

    The existing data on neutron-emission, kinetic-energy and mass distributions, and half-lives for spontaneous fission of the heavy actinides are reviewed. A comparison of the data for the Fm isotopes with heavier and lighter nuclides suggests that the properties of the heavy Fm isotopes may be unique and can qualitatively be explained on the basis of fragment shell effects, i.e., symmetric fission results in two fragments with configurations close to the doubly magic 132 Sn nucleus. The effect of excitation energy and the use of systematics and theoretical predictions of fission properties and half-lives in the identification of new heavy element isotopes is discussed. 54 references

  7. Actinide elements in aquatic and terrestrial environments

    International Nuclear Information System (INIS)

    Bondietti, E.A.

    1978-01-01

    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

  8. Determination of actinides by alpha spectrometric methods

    International Nuclear Information System (INIS)

    Galanda, D.

    2011-01-01

    The submitted thesis in its first part concern with content determination of plutonium, americium, uranium, thorium radionuclides, like the most significant representatives of actinides in environmental patterns, where by the primary consideration is a focusing on content of these actinides in samples of superior mycotic organisms - mushrooms. Following the published studies the mushrooms were monitored as organisms that could verify most of attributes putted on bioindicators in term of observation of substantial radionuclides in living environment. There were analyzed two groups of samples that came from two chosen locations, one of them is situated in Eastern Slovakia and the second one in West Slovakia. Except for mushrooms samples the examined radionuclides volumes were determined even in specimens of soil sub-base and some plants from chosen localities. The liquid - liquid extraction methods were used for determination of mass activities of actinides in samples for radiochemical separation of monitored radionuclides. The obtained results of plutonium and americium mass activities determination's lead us to carry out experiments that proved abilities of superior mycotic organisms to absorb and accumulate alpha radionuclides in their textures. We choose the oyster mushroom (Pleurotus ostreatus) species as an experimental object. Sporocarps of this mushroom were cultivated on substratum which is commercially exploited to cultivate it whereby this substratum was purposely contaminated by known activities of 239 Pu and 241 Am. We prepared five autonomous samples together. The values of mass activities of 239 Pu and 241 Am obtained by following analysis of prepared samples showed the ability of mushrooms to absorb observed actinides in their texture structures. On the basis of obtained mass activities it was possible to evaluate and numerically determine a transmitting factor's attributes of monitored radionuclides in sporocarps and in sub-base. Accordingly we

  9. Actinide behavior in the integral fast reactor

    International Nuclear Information System (INIS)

    Courtney, J.C.

    1993-05-01

    Goal of this project is to determine the consumption of Np-237, Pu-240, Am-241, and Am-243 in the Integral Fast Reactor (IFR) fuel cycle. These four actinides set the long term waste management criteria for spent nuclear fuel; if it can be demonstrated that they can be efficiently consumed in the IFR, then requirements for nuclear waste repositories can be much less demanding. Irradiations in the Experimental Breeder Reactor II (EBR-II) at Argonne National Laboratory's site near Idaho Falls, Idaho, will be conducted to determine fission and transmutation rates for the four nuclides. The experimental effort involves target package design, fabrication, quality assurance, and irradiation. Post irradiation analyses are required to determine the fission rates and neutron spectra in the EBR-II core

  10. Role of actinide behavior in waste management

    International Nuclear Information System (INIS)

    Bartlett, J.W.

    1976-01-01

    For purposes of assessing the safety of repositories of radioactive wastes placed in geologic isolation, actinide behavior in the environment has been interpreted in terms of five steps of prediction: analysis of repository stability; geosphere transport; the geosphere-biosphere interface; biosphere transport; and biosphere consequences. Each step in the analysis requires models of nuclide behavior and data on the physical and chemical properties of the radioactivity. The scope of information required in order to make reliable safety assessments has been outlined. All steps in the assessment process are coupled; reliable models and data are therefore needed for each step. The prediction phase of safety assessment is also coupled to activities concerned with waste treatment, selection of the final form of the waste, and selection of repository sites and designs. Results of the predictions can impact these activities

  11. Light element thermodynamics related to actinide separations

    International Nuclear Information System (INIS)

    Johnson, I.; Johnson, C.E.

    1997-01-01

    The accumulation of waste from the last five decades of nuclear reactor development has resulted in large quantities of materials of very diverse chemical composition. An electrometallurgical (EM) method is being developed to separate the components of the waste into several unique streams suitable for permanent disposal and an actinide stream suitable for retrievable storage. The principal types of nuclear wastes are spent oxide or metallic fuel. Since the EM module requires a metallic feed, and oxygen interferes with its operation, the oxide fuel has to be reduced prior to EM treatment. Further, the wastes contain, in addition to oxygen, other light elements (first- and second-row elements) that may also interfere with the operation of the EM module. The extent that these light elements interfere with the operation of the EM module has been determined by chemical thermodynamic calculations. (orig.)

  12. The role of humic acid on the formation of HAS (hydroxy-aluminosilicate) colloid-borne actinides

    Energy Technology Data Exchange (ETDEWEB)

    Priemyshev, A.; Kim, M.A. [Inst. fuer Radiochemie, Technische Universitaet Muenchen, D-85748 Garching (Germany); Breban, D.; Panak, P.J.; Yun, J.I.; Kim, J.I.; Fanghanel, Th. [Inst. fuer Nukleare Entsorgung, Forschungszentrum Karlsruhe, D-76021 Karlsruhe (Germany); Mansel, A. [Inst. fuer Interdisziplinaere Isotopenforschung, Georadiochemie, Leipzig, D-04318 Leipzig (Germany)

    2005-07-01

    Full text of publication follows: One of the major unknowns in the process of actinide migration is the formation of their colloid-borne species. Previous studies have been directed to the incorporation of actinides into HAS (hydroxy-aluminosilicate) colloids generated by the nucleation of Si and Al. The present work further pursues the behaviour of actinides at HAS colloid formation but in the presence of humic acid that is known to be an ubiquitous groundwater constituent. The formation and degree of stability of the aluminosilicate binding for the generation of HAS colloids are investigated at first in the absence of actinides. Free and complexed Al resulting from ligand competitions reactions for the complexation of Al with mono-silicic acid, poly-silicic acid and EDTA are monitored spectroscopically by colour reaction. The second part of the study concentrates on the formation and stability of humic colloids using {sup 14}C-labeled humic acid. The activity distribution is ascertained in the ionic, colloidal and precipitated fractions under different conditions of colloid formation, e.g. as a function of pH, time, humic acid and Al concentration. The third part follows the appraisal of appropriate conditions under which stable HAS and humic colloids are formed, and their interaction with actinides, either separately or in competition. Trace actinides of different oxidation states {sup 241}Am(III), {sup 234}Th(IV) and {sup 233}U(VI) are taken for the purpose. HAS colloids generated from poly-silicic acid at neutral pH show EDTA-resistance, whereas HAS colloids formed from mono-silicic acid become EDTA-resistant only by aging (> one month). Humic acid appears to stabilize HAS colloids, unless the loading capacity of humic acid for the Al ion is exceeded. The incorporation of actinides into the colloidal phase is generally enhanced in the presence of humic acid. Synergic effects produce chimeric HAS-humic colloids into which tri-, tetra- and hexavalent actinides

  13. Radiochemical studies of neutron deficient actinide isotopes

    International Nuclear Information System (INIS)

    Williams, K.E.

    1978-04-01

    The production of neutron deficient actinide isotopes in heavy ion reactions was studied using alpha, gamma, x-ray, and spontaneous fission detection systems. A new isotope of berkelium, 242 Bk, was produced with a cross-section of approximately 10 μb in reactions of boron on uranium and nitrogen on thorium. It decays by electron capture with a half-life of 7.0 +- 1.3 minutes. The alpha-branching ratio for this isotope is less than 1% and the spontaneous fission ratio is less than 0.03%. Studies of (Heavy Ion, pxn) and (Heavy Ion, αxn) transfer reactions in comparison with (Heavy ion, xn) compound nucleus reactions revealed transfer reaction cross-sections equal to or greater than the compound nucleus yields. The data show that in some cases the yield of an isotope produced via a (H.I.,pxn) or (H.I.,αxn) reaction may be higher than its production via an xn compound nucleus reaction. These results have dire consequences for proponents of the ''Z 1 + Z 2 = Z/sub 1+2/'' philosophy. It is no longer acceptable to assume that (H.I.,pxn) and (H.I.,αxn) product yields are of no consequence when studying compound nucleus reactions. No evidence for spontaneous fission decay of 228 Pu, 230 Pu, 232 Cm, or 238 Cf was observed indicating that strictly empirical extrapolations of spontaneous fission half-life data is inadequate for predictions of half-lives for unknown neutron deficient actinide isotopes

  14. Archetypes for actinide-specific chelating agents

    International Nuclear Information System (INIS)

    Smith, W.L.

    1980-01-01

    The complexes of uranium and thorium with monomeric hydroxamic acids can serve as archetypes for an optimized macrochelate designed for tetravalent actinides. The eight-coordinate complexes, Th(i-PrN(O)C(O)R) 4 , where R = tert-butyl or R = neopentyl, have been synthesized and their structures have been determined by x-ray diffraction. The bulky alkyl substituents impart remarkable volatility and hydrocarbon solubility to these complexes, and the steric interactions of these substituents largely determine the structures. When R = tert-butyl, the substituents occupy the corners of a tetrahedron and force the complex into a distorted cubic geometry with crystallographic S 4 symmetry. Insertion of a methylene group between the carbonyl carbon and the tert-butyl group relaxes the steric requirements, and the coordination polyhedron of the neopentyl derivative is close to the mmmm isomer of the trigonal-faced dodecahedron. Uranium tetrachloride was quantitatively oxidized via an oxygen transfer reaction with two equivalents of N-phenylbenzohydroxamic acid anion (PBHA) in tetrahydrofuran (THF) to form UO 2 Cl(PBHA)(THF) 2 and benzanilide. The structure of the uranyl complex has been determined from x-ray diffraction data; the linear uranyl ion is surrounded by a planar pentagonal array composed of two hydroxamate oxygen atoms, a chloride ion and two THF oxygens, such that the chloride ion is opposite the hydroxamate group. That the THF and phenyl rings are twisted from this equatorial plane limits the molecular geometry to that of the C 1 point group. Some aspects of the chemistry of hydroxamic acids and of their incorporation into molecules that may serve as precursors of tetravalent actinide specific sequestering agents have also been investigated

  15. Radiochemical studies of neutron deficient actinide isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Williams, K.E.

    1978-04-01

    The production of neutron deficient actinide isotopes in heavy ion reactions was studied using alpha, gamma, x-ray, and spontaneous fission detection systems. A new isotope of berkelium, /sup 242/Bk, was produced with a cross-section of approximately 10 ..mu..b in reactions of boron on uranium and nitrogen on thorium. It decays by electron capture with a half-life of 7.0 +- 1.3 minutes. The alpha-branching ratio for this isotope is less than 1% and the spontaneous fission ratio is less than 0.03%. Studies of (Heavy Ion, pxn) and (Heavy Ion, ..cap alpha..xn) transfer reactions in comparison with (Heavy ion, xn) compound nucleus reactions revealed transfer reaction cross-sections equal to or greater than the compound nucleus yields. The data show that in some cases the yield of an isotope produced via a (H.I.,pxn) or (H.I.,..cap alpha..xn) reaction may be higher than its production via an xn compound nucleus reaction. These results have dire consequences for proponents of the ''Z/sub 1/ + Z/sub 2/ = Z/sub 1+2/'' philosophy. It is no longer acceptable to assume that (H.I.,pxn) and (H.I.,..cap alpha..xn) product yields are of no consequence when studying compound nucleus reactions. No evidence for spontaneous fission decay of /sup 228/Pu, /sup 230/Pu, /sup 232/Cm, or /sup 238/Cf was observed indicating that strictly empirical extrapolations of spontaneous fission half-life data is inadequate for predictions of half-lives for unknown neutron deficient actinide isotopes.

  16. Pyrometallurgical processes for recovery of actinide elements

    International Nuclear Information System (INIS)

    Battles, J.E.; Laidler, J.J.; McPheeters, C.C.; Miller, W.E.

    1994-01-01

    A metallic fuel alloy, nominally U-20-Pu-lOZr, is the key element of the Integral Fast Reactor (IFR) fuel cycle. Metallic fuel permits the use of an innovative, simple pyrometallurgical process, known as pyroprocessing, (the subject of this report), which features fused salt electrorefining of the spent fuel. Electrorefining separates the actinide elements from fission products, without producing a separate stream of plutonium. The plutonium-bearing product is contaminated with higher actinides and with a minor amount of rare earth fission products, making it diversion resistant while still suitable as a fuel material in the fast spectrum of the IFR core. The engineering-scale demonstration of this process will be conducted in the refurbished EBR-II Fuel Cycle Facility, which has entered the start-up phase. An additional pyrometallurgical process is under development for extracting transuranic (TRU) elements from Light Water Reactor (LWR) spent fuel in a form suitable for use as a feed to the IFR fuel cycle. Four candidate extraction processes have been investigated and shown to be chemically feasible. The main steps in each process are oxide reduction with calcium or lithium, regeneration of the reductant and recycle of the salt, and separation of the TRU product from the bulk uranium. Two processes, referred to as the lithium and salt transport (calcium reductant) processes, have been selected for engineering-scale demonstration, which is expected to start in late 1993. An integral part of pyroprocessing development is the treatment and packaging of high-level waste materials arising from the operations, along with the qualification of these waste forms for disposal in a geologic repository

  17. Studies of actinides in a superanoxic fjord

    Energy Technology Data Exchange (ETDEWEB)

    Roos, P.

    1997-04-01

    Water column and sediment profiles of Pu, Am, Th and U have been obtained in the superanoxic Framvaren fjord, southern Norway. The concentration of bomb test fallout Pu, Am as well as `dissolved` Th in the bottom water are the highest recorded in the marine environment. The behaviour of the actinides in the anoxic water mass is to a large extent governed by the behaviour of the colloidal material. Ultrafiltration reveals that 40-60% of the actinides are associated to the large colloids, surprisingly this is valid also for U. The sediment acts as a source for Pu, Am, and Th to the water column but primarily as a sink for U. The remobilization of Pu, Am and Th is evident from the water column profiles which have similar diffusion shape profiles as other constituents originating from the sediments. The vertical eddy diffusion coefficient calculated from the Pu profile is in the same order of magnitude as reported from the H{sub 2}S profile. Decreased bottom water concentrations (but a constant water column inventory) between 1989 and 1995 as well as pore water Pu concentrations nearly identical to the overlaying bottom water indicates that the present Pu flux from the sediments are low. Contrary to Pu and Am, the water column Th inventory ({sup 232}Th and {sup 230}Th) continues to increase. The flux of {sup 232}Th from the sediments was determined from changes in water column inventory between 1989 and 1995 and from a pore water profile to be in the order of 2-8 Bq/m{sup 2}/y. 208 refs.

  18. Pyrometallurgical processes for recovery of actinide elements

    Energy Technology Data Exchange (ETDEWEB)

    Battles, J.E.; Laidler, J.J.; McPheeters, C.C.; Miller, W.E.

    1994-01-01

    A metallic fuel alloy, nominally U-20-Pu-lOZr, is the key element of the Integral Fast Reactor (IFR) fuel cycle. Metallic fuel permits the use of an innovative, simple pyrometallurgical process, known as pyroprocessing, (the subject of this report), which features fused salt electrorefining of the spent fuel. Electrorefining separates the actinide elements from fission products, without producing a separate stream of plutonium. The plutonium-bearing product is contaminated with higher actinides and with a minor amount of rare earth fission products, making it diversion resistant while still suitable as a fuel material in the fast spectrum of the IFR core. The engineering-scale demonstration of this process will be conducted in the refurbished EBR-II Fuel Cycle Facility, which has entered the start-up phase. An additional pyrometallurgical process is under development for extracting transuranic (TRU) elements from Light Water Reactor (LWR) spent fuel in a form suitable for use as a feed to the IFR fuel cycle. Four candidate extraction processes have been investigated and shown to be chemically feasible. The main steps in each process are oxide reduction with calcium or lithium, regeneration of the reductant and recycle of the salt, and separation of the TRU product from the bulk uranium. Two processes, referred to as the lithium and salt transport (calcium reductant) processes, have been selected for engineering-scale demonstration, which is expected to start in late 1993. An integral part of pyroprocessing development is the treatment and packaging of high-level waste materials arising from the operations, along with the qualification of these waste forms for disposal in a geologic repository.

  19. Studies of actinides in a superanoxic fjord

    International Nuclear Information System (INIS)

    Roos, P.

    1997-04-01

    Water column and sediment profiles of Pu, Am, Th and U have been obtained in the superanoxic Framvaren fjord, southern Norway. The concentration of bomb test fallout Pu, Am as well as 'dissolved' Th in the bottom water are the highest recorded in the marine environment. The behaviour of the actinides in the anoxic water mass is to a large extent governed by the behaviour of the colloidal material. Ultrafiltration reveals that 40-60% of the actinides are associated to the large colloids, surprisingly this is valid also for U. The sediment acts as a source for Pu, Am, and Th to the water column but primarily as a sink for U. The remobilization of Pu, Am and Th is evident from the water column profiles which have similar diffusion shape profiles as other constituents originating from the sediments. The vertical eddy diffusion coefficient calculated from the Pu profile is in the same order of magnitude as reported from the H 2 S profile. Decreased bottom water concentrations (but a constant water column inventory) between 1989 and 1995 as well as pore water Pu concentrations nearly identical to the overlaying bottom water indicates that the present Pu flux from the sediments are low. Contrary to Pu and Am, the water column Th inventory ( 232 Th and 230 Th) continues to increase. The flux of 232 Th from the sediments was determined from changes in water column inventory between 1989 and 1995 and from a pore water profile to be in the order of 2-8 Bq/m 2 /y. 208 refs

  20. 26 CFR 5f.103-2 - Public approval of industrial development bonds.

    Science.gov (United States)

    2010-04-01

    ... years and to pay reasonable incidental costs of the refunding (e.g., legal and accounting fees, printing... elected executive officer, (iii) In the case of a State, the chief elected legal officer of the State's... machine shop and hardware manufacturing plant”, “400-room airport hotel building”, “dock facility for...

  1. Thermodynamics and Structure of Actinide(IV) Complexes with Nitrilotriacetic Acid

    Energy Technology Data Exchange (ETDEWEB)

    Bonin, L.; Guillaumont, D.; Jeanson, A.; Den Auwer, C.; Moisy, Ph. [CEA Marcoule, DEN, DRCP, SCPS, F-30207 Bagnols Sur Ceze (France); Grigoriev, M. [RAS, AN Frumkin Inst Phys Chem and Electrochem, Moscow 119991 (Russian Federation); Berthet, J.C. [CEA Saclay, DSM, IRAMIS, URA 331, Serv Chim Mol, CNRS, F-91191 Gif Sur Yvette (France); Hennig, C.; Scheinost, A. [Forschungszentrum Dresden Rossendorf, Inst Radiochem, D-01314 Dresden (Germany)

    2009-05-15

    Nitrilotriacetic acid, commonly known as NITA (N(CH{sub 2}CO{sub 2}H){sub 3}), can be considered a representative of the polyamino-carboxylic family. The results presented in this paper describe the thermodynamical complexation and structural investigation of An(IV) complexes with NTA in aqueous solution. In the first part, the stability constants of the An(IV) complexes (An = Pu, Np, U, and Th) have been determined by spectrophotometry. In the second part, the coordination spheres of the actinide cation in these complexes have been described using extended X-ray absorption fine structure spectroscopy and compared to the solid-state structure of (Hpy){sub 2}[U(NTA){sub 2}].H{sub 2}O. These data are further compared to quantum chemical calculations, and their evolution across the actinide series is discussed. In particular, an interpretation of the role of the nitrogen atom in the coordination mode is proposed. These results are considered to be model behavior of polyamino-carboxylic ligands such as diethylenetriamine pentaacetic acid, which is nowadays the best candidate for a chelating agent in the framework of actinide decorporation for the human body. (authors)

  2. Investigation of actinides speciation within the presence of ligands of interest for decorporation

    International Nuclear Information System (INIS)

    Bonin, L.

    2008-01-01

    Data about the behaviour of actinides in biological media are required in order to investigate their decorporation. Those data are obtained through in vivo experiments and the study of chemical speciation of actinides within the presence of biological constituents. A part of this work consists in the development of a method leading to the determination of the speciation of actinides at the oxidation state +IV within the presence of a complexing species, as well as its structure. The method was applied to two types of ligands: 1) a constituent of blood plasma: the citrate anion. The various complexes formed were investigated and their formation constants were quantified. The coordination mode of the ligand was then clarified through a structural study of the complexes, underlining the role of only one carboxylic site and of the alcohol function. 2) chelating agents used for decorporation. The formation constants of complexes of An(IV) with NTA and DTPA were determined. The coordination number of the metallic cation in those complexes as well as the role of the nitrogen atom were proved. Lastly, the behaviour of Pu(IV) within the presence of LIHOPO was investigated. This chelating agent, more efficient than DTPA in the case of in vivo decorporation of Np, forms very stable complexes with the metallic cation. One of those complexes can be assumed to present a stoichiometry 2:3. (author)

  3. Development of Radioanalytical and Microanalytical Procedures for the Determination of Actinides in Environmental Samples

    International Nuclear Information System (INIS)

    Macsik, Zsuzsanna; Vajda, Nora; Bene, Balazs; Varga, Zsolt

    2008-01-01

    A radio-analytical procedure has been developed for the simultaneous determination of actinides in swipe samples by alpha-spectrometry after the separation of the actinides by extraction chromatography. The procedure is based on the complete decomposition of the sample by destruction with microwave digestion or ashing in furnace. Actinides are separated on an extraction chromatographic column filled with TRU resin (product of Eichrom Industries Inc.). Alpha sources prepared from the separated fractions of americium, plutonium, thorium and uranium are counted by alpha spectrometry. Micro-analytical procedure is being developed for the location and identification of individual particles containing fissile material using solid state nuclear track detectors. The parameters of alpha and fission track detection have been optimized and a procedure has been elaborated to locate the particles on the sample by defining the coordinates of the tracks created by the particles on the track detector. Development of a procedure is planned to separate the located particles using micromanipulator and these particles will be examined individually by different micro- and radio-analytical techniques. (authors)

  4. Actinide chemistry research supporting the Waste Isolation Pilot Plant (WIPP): FY94 results

    Energy Technology Data Exchange (ETDEWEB)

    Novak, C.F. [ed.

    1995-08-01

    This document contains six reports on actinide chemistry research supporting the Waste Isolation Pilot Plant (WIPP). These reports, completed in FY94, are relevant to the estimation of the potential dissolved actinide concentrations in WIPP brines under repository breach scenarios. Estimates of potential dissolved actinide concentrations are necessary for WIPP performance assessment calculations. The specific topics covered within this document are: the complexation of oxalate with Th(IV) and U(VI); the stability of Pu(VI) in one WIPP-specific brine environment both with and without carbonate present; the solubility of Nd(III) in a WIPP Salado brine surrogate as a function of hydrogen ion concentration; the steady-state dissolved plutonium concentrations in a synthetic WIPP Culebra brine surrogate; the development of a model for Nd(III) solubility and speciation in dilute to concentrated sodium carbonate and sodium bicarbonate solutions; and the development of a model for Np(V) solubility and speciation in dilute to concentrated sodium Perchlorate, sodium carbonate, and sodium chloride media.

  5. Actinide chemistry research supporting the Waste Isolation Pilot Plant (WIPP): FY94 results

    International Nuclear Information System (INIS)

    Novak, C.F.

    1995-08-01

    This document contains six reports on actinide chemistry research supporting the Waste Isolation Pilot Plant (WIPP). These reports, completed in FY94, are relevant to the estimation of the potential dissolved actinide concentrations in WIPP brines under repository breach scenarios. Estimates of potential dissolved actinide concentrations are necessary for WIPP performance assessment calculations. The specific topics covered within this document are: the complexation of oxalate with Th(IV) and U(VI); the stability of Pu(VI) in one WIPP-specific brine environment both with and without carbonate present; the solubility of Nd(III) in a WIPP Salado brine surrogate as a function of hydrogen ion concentration; the steady-state dissolved plutonium concentrations in a synthetic WIPP Culebra brine surrogate; the development of a model for Nd(III) solubility and speciation in dilute to concentrated sodium carbonate and sodium bicarbonate solutions; and the development of a model for Np(V) solubility and speciation in dilute to concentrated sodium Perchlorate, sodium carbonate, and sodium chloride media

  6. Development of Radioanalytical and Microanalytical Procedures for the Determination of Actinides in Environmental Samples

    Energy Technology Data Exchange (ETDEWEB)

    Macsik, Zsuzsanna [Institute of Nuclear Techniques, Moegyetem rakpart 9, H-1111 Budapest (Hungary); Vajda, Nora [RadAnal Ltd., Bimbo ut 119/a, H-1026 Budapest (Hungary); Bene, Balazs [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Varga, Zsolt [Institute of Isotopes, Konkoly-Thege M. ut 29-33, H-1121 Budapest (Hungary)

    2008-07-01

    A radio-analytical procedure has been developed for the simultaneous determination of actinides in swipe samples by alpha-spectrometry after the separation of the actinides by extraction chromatography. The procedure is based on the complete decomposition of the sample by destruction with microwave digestion or ashing in furnace. Actinides are separated on an extraction chromatographic column filled with TRU resin (product of Eichrom Industries Inc.). Alpha sources prepared from the separated fractions of americium, plutonium, thorium and uranium are counted by alpha spectrometry. Micro-analytical procedure is being developed for the location and identification of individual particles containing fissile material using solid state nuclear track detectors. The parameters of alpha and fission track detection have been optimized and a procedure has been elaborated to locate the particles on the sample by defining the coordinates of the tracks created by the particles on the track detector. Development of a procedure is planned to separate the located particles using micromanipulator and these particles will be examined individually by different micro- and radio-analytical techniques. (authors)

  7. U/Th-isotopes as natural analogues for the mobility of actinides in granitic rocks

    International Nuclear Information System (INIS)

    Mengel, K.; Gerdes, A.

    2001-01-01

    The short-lived decay products of 238 U ( 234 U and 230 Th) can be used as natural analogues for actinides in a hard rock repository. Their mobility in the past may serve as a key for understanding actinide migration in the future. For generally old calcites of the HRL Aespoethe age of disturbance of 238 U/ 234 U and 234 U/ 230 Th activity ratios ranges from 30 000 to 436 000 years at degrees of disturbance ranging from 0.5 to 6.7. The results obtained imply that during the past 440 000 years U was mobile throughout the tunnel sections of the HRL Aespoeinvestigated here. For the FL Grimsel, the disequilibrium states of the 234 U/ 238 U and 230 Th/ 234 U activity ratios in fracture minerals (calcites silicates) also imply that the reactions causing isotopic disturbances have occurred within the past 500 000 years. The U/Th-isotope data of both the samples from the HRL Aespoeand the FL Grimsel have in common the mobilization of U in secondary fracture minerals by migrating solutions within the past 500 000 years. As for the question of a final disposal of radioactive waste in granite host rocks, the transport of U - and thus of similarly behaving actinides - in migrating underground solutions can therefore not be ruled out, if suitable hydraulic systems are considered. (orig.)

  8. Lanthanide - actinide separation: a challenge in the back end of nuclear fuel cycle

    International Nuclear Information System (INIS)

    Mohapatra, P.K.

    2015-01-01

    Due to their similar size and chemical state, separation of trivalent lanthanide and actinide ions has always been a challenging topic of research. Of late, the growing concern for the radioactive waste management in the back end of the nuclear fuel cycle has led to the possibility of transmuting the long-lived transuranides in high flux reactors. This necessitates the development of processes for the separation of lanthanides and actinides in acidic/low pH media. In view of the high absorption cross section of few lanthanides, their presence in relatively large proportion (10-100 times) impedes the transmutation process. Processes such as the TRAMEX and TALSPEAK have been used for the separation of lanthanides from trivalent actinides. Of late soft donor ligands containing S and N donor atoms have been used for the selective extraction of trivalent actinide ions. The commercially available S-donor compound, CYANEX 301 (bis(2,4,4-trimethylpentyl) dithiophosphinic acid) has been used to yield separation factor (S.F.) values in the excess of 6000. Synergistic extraction with N-donor ligands such as 2,2'-bipyridyl and 1,10-phenanthroline have yielded S.F. values close to 40,000. N-donor ligands such as BTP (bis-triazinylpyridine), BTBP (bis-triazinylbipyridyl) and BTPhen (bis-triazinyl-phenanthroline) have been particularly effective from relatively acidic feed conditions. The present lecture will give a brief outline of the separation processes and experimental results of studies carried out using various S and N donor ligands. Use of room temperature ionic liquids for more favorable separations will be highlighted. Liquid membrane separation results for application to back end nuclear fuel cycle will also be discussed. (author)

  9. Human factors and safety issues associated with actinide retrieval from spent light water reactor fuel assemblies

    International Nuclear Information System (INIS)

    Spelt, P.F.

    1992-01-01

    A major problem in environmental restoration and waste management is the disposition of used fuel assemblies from the many light water reactors in the United States, which present a radiation hazard to those whose job is to dispose of them, with a similar threat to the general environment associated with long-term storage in fuel repositories around the country. Actinides resident in the fuel pins as a result of their use in reactor cores constitute a significant component of this hazard. Recently, the Department of Energy has initiated an Actinide Recycle Program to study the feasibility of using pyrochemical (molten salt) processes to recover actinides from the spent fuel assemblies of commercial reactors. This project concerns the application of robotics technology to the operation and maintenance functions of a plant whose objective is to recover actinides from spent fuel assemblies, and to dispose of the resulting hardware and chemical components from this process. Such a procedure involves a number of safety and human factors issues. The purpose of the project is to explore the use of robotics and artificial intelligence to facilitate accomplishment of the program goals while maintaining the safety of the humans doing the work and the integrity of the environment. This project will result in a graphic simulation on a Silicon Graphics workstation as a proof of principle demonstration of the feasibility of using robotics along with an intelligent operator interface. A major component of the operator-system interface is a hybrid artificial intelligence system developed at Oak Ridge National Laboratory, which combines artificial neural networks and an expert system into a hybrid, self-improving computer-based system interface. 10 refs

  10. Soft X-ray scanning transmission X-ray microscopy (STXM) of actinide particles.

    Science.gov (United States)

    Nilsson, Hans J; Tyliszczak, Tolek; Wilson, Richard E; Werme, Lars; Shuh, David K

    2005-09-01

    A descriptive account is given of our most recent research on the actinide dioxides with the Advanced Light Source Molecular Environmental Science (ALS-MES) Beamline 11.0.2 soft X-ray scanning transmission X-ray microscope (STXM) at the Lawrence Berkeley National Laboratory (LBNL). The ALS-MES STXM permits near-edge X-ray absorption fine structure (NEXAFS) and imaging with 30-nm spatial resolution. The first STXM spectromicroscopy NEXAFS spectra at the actinide 4d5/2 edges of the imaged transuranic particles, NpO2 and PuO2, have been obtained. Radiation damage induced by the STXM was observed in the investigation of a mixed oxidation state particle (Np(V,VI)) and was minimized during collection of the actual spectra at the 4d5/2 edge of the Np(V,VI) solid. A plutonium elemental map was obtained from an irregular PuO2 particle with the dimensions of 650 x 650 nm. The Pu 4d5/2 NEXAFS spectra were collected at several different locations from the PuO2 particle and were identical. A representative oxygen K-edge spectrum from UO2 was collected and resembles the oxygen K-edge from the bulk material. The unique and current performance of the ALS-MES STXM at extremely low energies (ca. 100 eV) that may permit the successful measurement of the actinide 5d edge is documented. Finally, the potential of STXM as a tool for actinide investigations is briefly discussed.

  11. Actinide targets for the synthesis of super-heavy elements

    International Nuclear Information System (INIS)

    Roberto, J.B.; Alexander, C.W.; Boll, R.A.; Burns, J.D.; Ezold, J.G.; Felker, L.K.; Hogle, S.L.; Rykaczewski, K.P.

    2015-01-01

    Since 2000, six new super-heavy elements with atomic numbers 113 through 118 have been synthesized in hot fusion reactions of "4"8Ca beams on actinide targets. These target materials, including "2"4"2Pu, "2"4"4Pu, "2"4"3Am, "2"4"5Cm, "2"4"8Cm, "2"4"9Cf, and "2"4"9Bk, are available in very limited quantities and require specialized production and processing facilities resident in only a few research centers worldwide. This report describes the production and chemical processing of heavy actinide materials for super-heavy element research, current availabilities of these materials, and related target fabrication techniques. The impact of actinide materials in super-heavy element discovery is reviewed, and strategies for enhancing the production of rare actinides including "2"4"9Bk, "2"5"1Cf, and "2"5"4Es are described.

  12. Advanced techniques for actinide spectroscopy (ATAS 2012). Abstract book

    Energy Technology Data Exchange (ETDEWEB)

    Foerstendorf, Harald; Mueller, Katharina; Steudtner, Robin [eds.

    2012-07-01

    The abstract book of the International workshop on advanced techniques for actinide spectroscopy (ATAS 2012) include contributions concerning the following issues: environmental applications, NMR spectroscopy, vibrational spectroscopy, X-ray spectroscopy and theory, technical application: separation processes, emission spectroscopy.

  13. Advanced techniques for actinide spectroscopy (ATAS 2012). Abstract book

    International Nuclear Information System (INIS)

    Foerstendorf, Harald; Mueller, Katharina; Steudtner, Robin

    2012-01-01

    The abstract book of the International workshop on advanced techniques for actinide spectroscopy (ATAS 2012) include contributions concerning the following issues: environmental applications, NMR spectroscopy, vibrational spectroscopy, X-ray spectroscopy and theory, technical application: separation processes, emission spectroscopy.

  14. Evaluating the efficacy of a minor actinide burner

    International Nuclear Information System (INIS)

    Dobbin, K.D.; Kessler, S.F.; Nelson, J.V.; Omberg, R.P.; Wootan, D.W.

    1993-06-01

    The efficacy of a minor actinide burner can be evaluated by comparing safety and economic parameters to the support ratio. Minor actinide mass produced per unit time in this number of Light Water Reactors (LWRs) can be burned during the same time period in one burner system. The larger the support ratio for a given set of safety and economic parameters, the better. To illustrate this concept, the support ratio for selected Liquid Metal Reactor (LMR) burner core designs was compared with corresponding coolant void worths, a fundamental safety concern following the Chernobyl accident. Results can be used to evaluate the cost in reduced burning of minor actinides caused by LMR sodium void reduction efforts or to compare with other minor actinide burner systems

  15. Use of fast-spectrum reactors for actinide burning

    International Nuclear Information System (INIS)

    Chang, Yoon I.

    1991-01-01

    Finally, Integral Fast Reactor (IFR) pyroprocessing has been developed only in recent years and it appears to have potential as a relatively uncomplicated, effective actinide recovery process. In fact, actinide recycling occurs naturally in the IFR fuel cycle. Although still very much developmental, the entire IFR fuel cycle will be demonstrated on prototype-scale in conjunction with the EBR-II and its refurbished Fuel Cycle Facility starting in late 1991. A logical extension to this work, therefore, is to establish whether this IFR pyrochemical processing can be applied to extracting actinides from LWR spent fuel. This paper summarizes current thinking on the rationale for actinide recycle, its ramifications on the geologic repository and the current high-level waste management plans, and the necessary development programs. 4 figs., 4 tabs

  16. Thermochemical and thermophysical properties of minor actinide compounds

    International Nuclear Information System (INIS)

    Minato, Kazuo; Takano, Masahide; Otobe, Haruyoshi; Nishi, Tsuyoshi; Akabori, Mitsuo; Arai, Yasuo

    2009-01-01

    Burning or transmutation of minor actinides (MA: Np, Am, Cm) that are classified as the high-level radioactive waste in the current nuclear fuel cycle is an option for the advanced nuclear fuel cycle. Although the thermochemical and thermophysical properties of minor actinide compounds are essential for the design of MA-bearing fuels and analysis of their behavior, the experimental data on minor actinide compounds are limited. To support the research and development of the MA-bearing fuels, the property measurements were carried out on minor actinide nitrides and oxides. The lattice parameters and their thermal expansions were measured by high-temperature X-ray diffractometry. The specific heat capacities were measured by drop calorimetry and the thermal diffusivities by laser-flash method. The thermal conductivities were determined by the specific heat capacities, thermal diffusivities and densities. The oxygen potentials were measured by electromotive force method.

  17. Formation of actinides in irradiated HTGR fuel elements

    Energy Technology Data Exchange (ETDEWEB)

    dos Santos, A. M.

    1976-03-15

    Actinide nuclide concentrations of 11 spent AVR fuel elements were determined experimentally. The burnup of the spheres varied in the range between 10% and 100% fifa, the Th : U ratio was 5 : 1. The separation procedures for an actinide isolation were tested with highly irradiated ThO/sub 2/. Separation and decontamination factors are presented. Build-up of /sup 232/U was discussed. The AVR breeding rate was ascertained to be 0.5. The hazard potential of high activity waste was calculated. Actinide recovery factors were proposed in order to reduce the hazard potential of the waste by an actinide removal under consideration of the reprocessing technology which is available presently.

  18. Actinide removal from aqueous solution with activated magnetite

    International Nuclear Information System (INIS)

    Kochen, R.L.; Thomas, R.L.

    1987-01-01

    An actinide aqueous waste treatment process using activated magnetite has been developed at Rocky Flats. The use and effectiveness of various magnetites in lowering actinide concentrations in aqueous solution are described. Experiments indicate that magnetite particle size and pretreatment (activation of the magnetite surface with hydroxyl ions greatly influence the effective use of magnetite as an actinide adsorbent. With respect to actinide removal, Ba(OH) 2 -activated magnetite was more effective over a broader pH range than was NaOH-activated magnetite. About 50% less Ba(OH) 2 -activated magnetite was required to lower plutonium concentration from 10 -4 to 10 -8 g/l. 7 refs., 8 tabs

  19. What fits best minor actinides as a die material?

    International Nuclear Information System (INIS)

    Hinfray, J.

    2003-01-01

    Zirconolite might be the die material used to confine actinides definitively. Cea's teams have been investigating the ability of zirconolite to trap actinide atoms in its own crystal structure. These studies have been performed with 239 Pu that presents the same ability to set chemical links with the constituents of the die as 3 minor actinides do. Crystal materials like zirconolite are more sensitive to self irradiation than glass. The next step of the characterization of zirconolite is to evaluate its capacity to sustain self alpha irradiation. In order to do so, 238 Pu is used since its relatively short period (T = 87 years) allows an acceleration of the process : damages cumulated in the die material in 2 years will be equivalent to those produced by minor actinides for millions years. The results will be known in 2004. (A.C.)

  20. Lattice disorder in strongly correlated lanthanide and actinide intermetallics

    International Nuclear Information System (INIS)

    Booth, C.H.; Bauer, E.D.; Maple, M.B.; Lawrence, J.M.; Kwei, G.H.; Sarrao, J.L.

    2001-01-01

    Lanthanide and actinide intermetallic compounds display a wide range of correlated-electron behavior, including ferromagnetism, antiferromagnetism, nonmagnetic (Kondo) ground states, and so-called 'non-Fermi liquid' (NFL) behavior. The interaction between f electrons and the conduction band is a dominant factor in determining the ground state of a given system. However, lattice disorder can create a distribution of interactions, generating unusual physical properties. These properties may include NFL behavior in many materials. In addition, lattice disorder can cause deviations from standard Kondo behavior that is less severe than NFL behavior. A review of the lattice disorder mechanism within a tight-binding model is presented, along with measurements of the YbBCu 4 and UPd x Cu 5-x systems, demonstrating the applicability of the model. These measurements indicate that while the YbBCu 4 system appears to be well ordered, both site interchange and continuous bond-length disorder occur in the UPd x Cu 5-x series. Nevertheless, the measured bond-length disorder in UPdCu 4 does not appear to be enough to explain the NFL properties simply with the Kondo disorder model. (au)