WorldWideScience

Sample records for actinide biocolloid formation

  1. Actinide Biocolloid Formation in Brine by Halophilic Bacteria

    International Nuclear Information System (INIS)

    We examined the ability of a halophilic bacterium (WFP 1A) isolated from the Waste Isolation Pilot Plant (WIPP) site to accumulate uranium in order to determine the potential for biocolloid facilitated actinide transport. The bacterial cell Surface functional groups involved in the complexation of the actinide were determined by titration. Uranium, added as uranyl nitrate, was removed from solution at pH 5 by cells but at pH 7 and 9 very little uranium was removed due to its limited volubility. Although present as soluble species, uranyl citrate at pH 5, 7, and 9, and uranyl carbonate at pH 9 were not removed by the bacterium because they were not bioavailable due to their neutral or negative charge. Addition of uranyl EDTA to brine at pH 5, 7, and 9 resulted in the immediate precipitation of U. Transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS) analysis revealed that uranium was not only associated with the cell surface but also accumulated intracellulary as uranium-enriched granules. Extended X-ray absorption fine structure (EXAFS) analysis, of the bacterial cells indicated the bulk sample contained more than one uranium phase. Nevertheless these results show the potential for the formation of actinide bearing bacterial biocolloids that are strictly regulated by the speciation and bioavailability of the actinide

  2. Actinide Biocolloid Formation in Brine by Halophilic Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Gillow, J.B.; Francis, A.J.; Dodge, C.J.; Harris, R.; Beveridge, T.J.; Brady, P.V.; Papenguth, H.W.

    1999-07-28

    We examined the ability of a halophilic bacterium (WFP 1A) isolated from the Waste Isolation Pilot Plant (WIPP) site to accumulate uranium in order to determine the potential for biocolloid facilitated actinide transport. The bacterial cell Surface functional groups involved in the complexation of the actinide were determined by titration. Uranium, added as uranyl nitrate, was removed from solution at pH 5 by cells but at pH 7 and 9 very little uranium was removed due to its limited volubility. Although present as soluble species, uranyl citrate at pH 5, 7, and 9, and uranyl carbonate at pH 9 were not removed by the bacterium because they were not bioavailable due to their neutral or negative charge. Addition of uranyl EDTA to brine at pH 5, 7, and 9 resulted in the immediate precipitation of U. Transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS) analysis revealed that uranium was not only associated with the cell surface but also accumulated intracellulary as uranium-enriched granules. Extended X-ray absorption fine structure (EXAFS) analysis, of the bacterial cells indicated the bulk sample contained more than one uranium phase. Nevertheless these results show the potential for the formation of actinide bearing bacterial biocolloids that are strictly regulated by the speciation and bioavailability of the actinide.

  3. Role of Microbes as Biocolloids in the Transport of Actinides from a Deep Underground Radioactive Waste Repository

    Energy Technology Data Exchange (ETDEWEB)

    Dodge, C.J.; Dunn, M.; Francis, A.J.; Gillow, J.B.; Mantione, K.; Pansoy-Hjelvik, M.E.; Papenguth, H.W.; Strietelmeier, B.A.

    1998-12-17

    We investigated the interaction of dissolved actinides Th, U, Np Zgpu, and Am, with a pure and a mixed culture of halophilic bactezia isolated from the Waste Isolation H.Iot Plant repository under anaerobic conditions to evaluate their potentiaI transport as biocolloids from the waste site. The sizes of the bacterial cells studied ranged from ().54 x 0.48 pm to 7.7 x 0.67pm Using sequential mimofiltration, we determined the ~~ation of actinides with fi-ee-living (mobile) bacterial cells suspended in a fluid medium containing. NaCl or M=W12 brine, at various phaes of their growth cycIes. The number of suspended kcteria rangy-d born 106 to 109 cells ml-*. Tine amount of actinide associatd with the wspend~ cell fraction (cakzdated & mol cell-*) was very Iow: Th, 10-*2; U, 10-1s - 10-lS; - ~ Np, 1o-15- 10-19; Pu, 10-ls -10-21 ; and h, 10-1* - 10-*9 ; and it varied with the bacteihl - CUIture studied. l%e differe&es in the asswiation are amibuted to the extent of bioamxmdation and biosorption by the bacteria pH, the compo&on of the brine, and the speziation and bioavaiIability of the actinides.

  4. Radiochemically-Supported Microbial Communities: A Potential Mechanism for Biocolloid Production of Importance to Actinide Transport

    Energy Technology Data Exchange (ETDEWEB)

    Moser, Duane P [DRI; Hamilton-Brehm, Scott D [DRI; Fisher, Jenny C [DRI; Bruckner, James C [DRI; Kruger, Brittany [DRI; Sackett, Joshua [DRI; Russell, Charles E [DRI; Onstott, Tullis C [Princeton University; Czerwinski, Ken [University of Nevada-Las Vegas; Zavarin, Mavrik [lawrence Livermore National Laboratory; Campbell, James H [Northwest Missouri State University

    2014-06-01

    Due to the legacy of Cold War nuclear weapons testing, the Nevada National Security Site (NNSS, formerly known as the Nevada Test Site (NTS)) contains millions of Curies of radioactive contamination. Presented here is a summary of the results of the first comprehensive study of subsurface microbial communities of radioactive and nonradioactive aquifers at this site. To achieve the objectives of this project, cooperative actions between the Desert Research Institute (DRI), the Nevada Field Office of the National Nuclear Security Administration (NNSA), the Underground Test Area Activity (UGTA), and contractors such as Navarro-Interra (NI), were required. Ultimately, fluids from 17 boreholes and two water-filled tunnels were sampled (sometimes on multiple occasions and from multiple depths) from the NNSS, the adjacent Nevada Test and Training Range (NTTR), and a reference hole in the Amargosa Valley near Death Valley. The sites sampled ranged from highly-radioactive nuclear device test cavities to uncontaminated perched and regional aquifers. Specific areas sampled included recharge, intermediate, and discharge zones of a 100,000-km2 internally-draining province, known as the Death Valley Regional Flow System (DVRFS), which encompasses the entirety of the NNSS/NTTR and surrounding areas. Specific geological features sampled included: West Pahute and Ranier Mesas (recharge zone), Yucca and Frenchman Flats (transitional zone), and the Western edge of the Amargosa Valley near Death Valley (discharge zone). The original overarching question underlying the proposal supporting this work was stated as: Can radiochemically-produced substrates support indigenous microbial communities and subsequently stimulate biocolloid formation that can affect radionuclides in NNSS subsurface nuclear test/detonation sites? Radioactive and non-radioactive groundwater samples were thus characterized for physical parameters, aqueous geochemistry, and microbial communities using both DNA- and

  5. New insights into formation of trivalent actinides complexes with DTPA

    International Nuclear Information System (INIS)

    Complexation of trivalent actinides with DTPA (diethylenetriamine pentaacetic acid) was studied as a function of pcH and temperature in (Na,H)Cl medium of 0.1 M ionic strength. Formation constants of both complexes AnHDTPA- and AnDTPA2- (where An stands for Am, Cm, and Cf) were determined by TRLFS, CE-ICP-MS, spectrophotometry, and solvent extraction. The values of formation constants obtained from the different techniques are coherent and consistent with reinterpreted literature data, showing a higher stability of Cf complexes than Am and Cm complexes. The effect of temperature indicates that formation constants of protonated and non protonated complexes are exothermic with a high positive entropic contribution. DFT calculations were also performed on the An/DTPA system. Geometry optimizations were conducted on AnDTPA2- and AnHDTPA- considering all possible protonation sites. For both complexes, one and two water molecules in the first coordination sphere of curium were also considered. DFT calculations indicate that the lowest energy structures correspond to protonation on oxygen that is not involved in An-DTPA bonds and that the structures with two water molecules are not stable. (authors)

  6. Peculiarities of phase formation in synthesis of actinide waste forms

    International Nuclear Information System (INIS)

    The phase formation processes by synthesis of the materials with the zirconolite and pyrochlore structure are studied through the methods of the x-ray phase analysis and electron microscopy with the purpose of optimizing the conditions for production of the matrices, used for immobilization of the actinide-containing wastes. It is established, that 20 hours are required for achieving the equilibrium in the CaO-TiO2-ZrO2 system at 1300 deg C and 5 hours - at 1450-1550 deg C. More than 20 hours are required for achieving the equilibrium in the Gd2O3-TiO2 system at 1100 deg C, less than 20 hours at 1200 deg C, about 1 hour - at 1300 deg C and less than 1 hour - at 1400-1550 deg C. The slowest phase formation processes take place in the Gd2O3-ZrO2 system, whereby at 1550 deg C no complete synthesis was observed even during 48 hours. The products of reactions, performed at lower temperatures or durations, contained the components of the initial charge along with the target phases with the zirconolite or pyrochlore structure

  7. Heteroaggregation of nanoparticles with biocolloids and geocolloids.

    Science.gov (United States)

    Wang, Hongtao; Adeleye, Adeyemi S; Huang, Yuxiong; Li, Fengting; Keller, Arturo A

    2015-12-01

    The application of nanoparticles has raised concern over the safety of these materials to human health and the ecosystem. After release into an aquatic environment, nanoparticles are likely to experience heteroaggregation with biocolloids, geocolloids, natural organic matter (NOM) and other types of nanoparticles. Heteroaggregation is of vital importance for determining the fate and transport of nanoparticles in aqueous phase and sediments. In this article, we review the typical cases of heteroaggregation between nanoparticles and biocolloids and/or geocolloids, mechanisms, modeling, and important indicators used to determine heteroaggregation in aqueous phase. The major mechanisms of heteroaggregation include electric force, bridging, hydrogen bonding, and chemical bonding. The modeling of heteroaggregation typically considers DLVO, X-DLVO, and fractal dimension. The major indicators for studying heteroaggregation of nanoparticles include surface charge measurements, size measurements, observation of morphology of particles and aggregates, and heteroaggregation rate determination. In the end, we summarize the research challenges and perspective for the heteroaggregation of nanoparticles, such as the determination of αhetero values and heteroaggregation rates; more accurate analytical methods instead of DLS for heteroaggregation measurements; sensitive analytical techniques to measure low concentrations of nanoparticles in heteroaggregation systems; appropriate characterization of NOM at the molecular level to understand the structures and fractionation of NOM; effects of different types, concentrations, and fractions of NOM on the heteroaggregation of nanoparticles; the quantitative adsorption and desorption of NOM onto the surface of nanoparticles and heteroaggregates; and a better understanding of the fundamental mechanisms and modeling of heteroaggregation in natural water which is a complex system containing NOM, nanoparticles, biocolloids and geocolloids.

  8. Formation of new actinide nuclides and their reaction cross section

    International Nuclear Information System (INIS)

    Helium jet transfer system, which had been designed and constructed for the study of actinide nuclides, was examined for the transfer efficiency of recoils and fission products formed in the nuclear reaction induced by α particles. The efficiency was found to be close to unity for products coming out of a 232Th target bombarded with 110 MeV α particles of intensity less than 40 nA. Residual radio-activities of a target chamber and a collection chamber were also measured. (author)

  9. Discrete fragment model for apparent formation constants of actinide ions with humic substances

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Takayuki; Yoshida, Hatsumi; Aoyama, Shunsuke; Kobayashi, Taishi; Takagi, Ikuji [Kyoto Univ. (Japan). Dept. of Nuclear Engineering; Moriyama, Hirotake [Kyoto Univ., Osaka (Japan). Research Reactor Inst.

    2015-09-01

    A semi-empirical thermodynamic model was applied to estimate the apparent formation constants of actinide ions, i.e., Th(IV), Pu(IV) and Np(V), with humic substances (HSs), including humic and fulvic acids, over a wide range of solution conditions, i.e., pH, ionic strength, and HS and metal concentrations. The hypothetical HSs consist of humic and fulvic acids with nine types of simple organic ligands, which include aromatic and aliphatic carboxyl groups and phenol groups, as binding sites. The abundance of each binding site in the hypothetical HSs was determined via a fitting analysis using an acid-dissociation dataset for several HSs. To determine the apparent formation constant of a given metal ion with HSs, 54 specific binding sites were considered, including nine monodentate sites (1:1 metal/ligand complexes) and 45 bidentate sites (1:2 metal/ligand complexes). The formation constant of each monodentate binding was determined from the experimental data, while those of the bidentate bindings were determined by considering two monodentate bindings and the chelating effect, for which one of the adjustable parameters was introduced in the model. Introduction of the other parameter, which is related to the fraction of monodentate to bidentate sites (i.e., the heterogeneity), afforded the parameter values with good correlation with the apparent formation constant data. The present model with adjusted parameter values well reproduced the experimental apparent complex formation constants for actinide ion interaction with HSs in a wide range of solution conditions except for those obtained at trace concentrations.

  10. Complex formation of the lanthanides and actinides in lower oxidation states

    International Nuclear Information System (INIS)

    The coordination chemistry of the lanthanides (ln) and actinides (An) in lower oxidation states is discussed, including the hydration-solvation properties of Ln2+ and An2+ in aqueous and aqueous-ethanolic solutions and the formation of complexes with the tetraphenylborate ion and crown ethers. Some physicochemical properties of a number of novel compounds with crown ethers are reported. In this paper the difference in the properties of Ln2+ and An2+ with an fnd0 and fn-1d1 configuration and the ability of the fn-1 d1 compounds to form mixed condensed clusters with Gd2Cl3 are discussed. The properties of Ln and An elements in various oxidation states are compared with those of elements of other groups in the periodic table

  11. The complex formation of selected actinides (U, Np, Cm) with microbial ligands

    International Nuclear Information System (INIS)

    One of the urgent tasks in the field of nuclear technology is the final storage of radioactive substances. As a part of the safety requirements the protection of humans and the environment from the danger of radioactive substances in case of the release from the final storage is essential. For performing long-term safety calculations the detailed understanding of the physico-chemical effects and influences which cause the mobilisation and transport of actinides are necessary. The presented work was a discrete part of a project, which was focused on the clarification of the influence of microorganisms on the migration of actinides in case of the release of actinides from a final storage. The influence of microbial produced substances on the mobilisation of selected actinides was studied thereby. The microbial produced substances studied in this project were synthesized by bacteria from the Pseudomonas genus under special conditions. Fluorescent Pseudomonads secrete bacterial pyoverdin-type siderophores with a high potential to complex and transport metals, especially iron(III). The aim of the project was to determine how and under which conditions the bioligands are able to complex also radioactive substances and therefore to transport them. For this work the alpha-emitting actinides uranium, curium and neptunium were chosen because their long-life cycle and their radiotoxicity are a matter of particular interest. This work dealed with the interaction of the actinides U(VI), Np(V) and Cm(III) with model ligands simulating the functionality of the pyoverdins. So, such bioligands can essentially influence the behaviour of actinides in the environment. The results of this work contribute to a better understanding and assessment of the influence of the microbial ligands to the mobilisation and migration of the radionuclides. The outcomes could be used to quantify the actinide-mobilising effect of the bioligands, which are released, for example, in the vicinity of a

  12. Metabolic Toxicity Screening Using Electrochemiluminescence Arrays Coupled with Enzyme-DNA Biocolloid Reactors and Liquid Chromatography-Mass Spectrometry

    Science.gov (United States)

    Hvastkovs, Eli, G.; Schenkman, John B.; Rusling, James, F.

    2012-07-01

    New chemicals or drugs must be guaranteed safe before they can be marketed. Despite widespread use of bioassay panels for toxicity prediction, products that are toxic to a subset of the population often are not identified until clinical trials. This article reviews new array methodologies based on enzyme/DNA films that form and identify DNA-reactive metabolites that are indicators of potentially genotoxic species. This molecularly based methodology is designed in a rapid screening array that utilizes electrochemiluminescence (ECL) to detect metabolite-DNA reactions, as well as biocolloid reactors that provide the DNA adducts and metabolites for liquid chromatography-mass spectrometry (LC-MS) analysis. ECL arrays provide rapid toxicity screening, and the biocolloid reactor LC-MS approach provides a valuable follow-up on structure, identification, and formation rates of DNA adducts for toxicity hits from the ECL array screening. Specific examples using this strategy are discussed. Integration of high-throughput versions of these toxicity-screening methods with existing drug toxicity bioassays should allow for better human toxicity prediction as well as more informed decision making regarding new chemical and drug candidates.

  13. Imaging the formation of high-energy dispersion anomalies in the actinide UCoGa$_5$

    OpenAIRE

    Das, Tanmoy; Durakiewicz, Tomasz; Zhu, Jian-Xin; Joyce, John J.; Sarrao, John L.; Graf, Matthias J.

    2012-01-01

    We use angle-resolved photoemission spectroscopy (ARPES) to image the emergence of substaintial dispersion anomalies in the electronic renormalization of the actinide compound UCoGa$_5$ which 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 ($\\sim$130 meV) and high ($\\sim$1 eV) binding energies below the Fermi energy, ruling out any significant contribution of phonons. We perform numerica...

  14. Separation of californium from actinides and lanthanides in aqueous solution by electrochemical formation of amalgams

    International Nuclear Information System (INIS)

    The electrochemical reduction of transneptunium elements (Pu to Cf) and rare earths (Eu, Tm) from aqueous complexing solutions to amalgams was studied over a wide range of cathodic potentials in order to achieve optimal separation of californium. The reduction in acetate media (pH 4.5-4.6) at potentials around -1.7 to -1.9 V1 leads to a quantitative extraction of californium into the mercury phase, while more negative potentials are required for the reduction of the lighter transuranium elements and of the lanthanides. Hence, the optimal conditions for the separation of californium from the investigated actinides and lanthanides were determined. Separation factors α between 25 and 90 were found except in the case of Cf/Eu, where poor values (α varying from 7 to 12) were observed. More negative cathodic potentials decrease the selectivity of the reduction process. A similar study with lithium citrate solutions (pH ∝6) shows that satisfactory separation of californium from lighter and heavier actinides is achievable. A separation factor of 88 is obtained for Cf/Am at -1.98 V. The anodic stripping of mixed amalgams (Pu, Am, Cm, Bk, Tm and Cf) Hg in nitric and acetic acid soultions at potentials ranging from +0.1 to -0.7 V proceeds slowly and proved to be ineffective for the separation of californium from light actinides under conditions described. (orig.)

  15. Radiochemically-supported microbial communities. A potential mechanism for biocolloid production of importance to actinide transport

    Energy Technology Data Exchange (ETDEWEB)

    Moser, Duane P. [Desert Research Institute, Las Vegas, NV (United States); Hamilton-Brehm, Scott D. [Desert Research Institute, Las Vegas, NV (United States); Fisher, Jenny C. [Univ. of Wisconsin, Milwaukee, WI (United States); Bruckner, James C. [Desert Research Institute, Las Vegas, NV (United States); Kruger, Brittany [Desert Research Institute, Las Vegas, NV (United States); Sackett, Joshua [Desert Research Institute, Las Vegas, NV (United States); Russell, Charles E. [Desert Research Institute, Las Vegas, NV (United States); Onstott, Tullis C. [Princeton Univ., NJ (United States); Czerwinski, Ken [Univ. of Nevada, Las Vegas, NV (United States); Zavarin, Mavrik [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Campbell, James H. [Northwest Missouri State Univ., Maryville, MO (United States)

    2015-03-20

    The work described here revealed the presence of diverse microbial communities located across 19 subsurface sites at the NNSS/NTTR and nearby locations. Overall, the diversity of microorganisms was high for subsurface habitats and variable between sites. As of this writing, preparations are being made to combine the Illumina sequences and 16S rRNA clone libraries with other non-NNSS/NTTR well sites of Southern Nevada Regional Flow System for a publication manuscript describing our very broad landscape scale survey of subsurface microbial diversity. Isolates DRI-13 and DRI-14 remain to be fully characterized and named in accordance with the conventions established by Bergey's Manual of Systematic Bacteriology. In preparation to be published, these microorganisms will be submitted to the American Type Culture Collection (ATCC) and the Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH (DSMZ).It is anticipated that the data resulting from this study in combination with other data sets that will allow us to produce a number of publications that will be impactful to the subsurface microbiology community.

  16. Microsome biocolloids for rapid drug metabolism and inhibition assessment by LC-MS

    OpenAIRE

    Bajrami, Besnik; Krishnan, Sadagopan; Rusling, James F.

    2008-01-01

    Rat liver microsomes attached to nanoparticles were used for LC-MS studies of CYP3A and 2E1 enzymes in metabolism of N-nitroso compounds. Using these biocolloids, turnover rates were measured within 2 min. Inhibitor IC50 values for ketoconazole (KET) and 4-methylpyrazole (4-MEP) were estimated.

  17. Microsome biocolloids for rapid drug metabolism and inhibition assessment by LC-MS

    Science.gov (United States)

    Bajrami, Besnik; Krishnan, Sadagopan; Rusling, James F.

    2012-01-01

    Rat liver microsomes attached to nanoparticles were used for LC-MS studies of CYP3A and 2E1 enzymes in metabolism of N-nitroso compounds. Using these biocolloids, turnover rates were measured within 2 min. Inhibitor IC50 values for ketoconazole (KET) and 4-methylpyrazole (4-MEP) were estimated. PMID:19356087

  18. Actinide oxalate complexes formation as a function of temperature by capillary electrophoresis coupled with inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Brunel, Benoit; Mendes, Mickael; Aupiais, Jean [CEA, DAM, DIF, Arpajon (France); Philippini, Violaine [Nice Univ. Sophia Antipolis (France). Inst. de Chimie de Nice

    2015-05-01

    Complexation of various actinides (U(VI), Np(V), Pu(V), Am(III)) by oxalato ligand was studied by capillary electrophoresis (ICPMS detection) in 0.1 mol L{sup -1} NaClO{sub 4} ionic strength solutions at various temperatures (15, 25, 35, 45 and 55 C). For each solution a unique peak was observed as a result of a fast equilibrium between the free ions and the complexes (labile systems). The results confirmed the formation of the 1:1, 1:2 and 1:3 complexes for U(VI) and Am(III); the formation of the 1:1 and 1:2 complexes for Np(V) and the formation of only 1 complex for Pu(V). For each complex, the thermodynamic parameters (the Gibbs energy Δ{sub r}G(T), the molar entropy change Δ{sub r}S(T) and the molar enthalpy change Δ{sub r}H(T{sup 0})) were fitted to the experimental data. The effect of the ionic medium was treated using the specific ion interaction theory and the thermodynamic parameters at zero ionic strength were compared to previously published data.

  19. Actinides-1981

    International Nuclear Information System (INIS)

    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

  20. 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.

  1. Actinide Solubility and Speciation in the WIPP

    Energy Technology Data Exchange (ETDEWEB)

    Reed, Donald T. [Los Alamos National Laboratory

    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. Advances in colloid and biocolloid transport in porous media: particle size-dependent dispersivity and gravity effects

    Science.gov (United States)

    Chrysikopoulos, Constantinos V.; Manariotis, Ioannis D.; Syngouna, Vasiliki I.

    2014-05-01

    Accurate prediction of colloid and biocolloid transport in porous media relies heavily on usage of suitable dispersion coefficients. The widespread procedure for dispersion coefficient determination consists of conducting conservative tracer experiments and subsequently fitting the collected breakthrough data with a selected advection-dispersion transport model. The fitted dispersion coefficient is assumed to characterize the porous medium and is often used thereafter to analyze experimental results obtained from the same porous medium with other solutes, colloids, and biocolloids. The classical advection-dispersion equation implies that Fick's first law of diffusion adequately describes the dispersion process, or that the dispersive flux is proportional to the concentration gradient. Therefore, the above-described procedure inherently assumes that the dispersive flux of all solutes, colloids and biocolloids under the same flow field conditions is exactly the same. Furthermore, the available mathematical models for colloid and biocoloid transport in porous media do not adequately account for gravity effects. Here an extensive laboratory study was undertaken in order to assess whether the dispersivity, which traditionally has been considered to be a property of the porous medium, is dependent on colloid particle size, interstitial velocity and length scale. The breakthrough curves were successfully simulated with a mathematical model describing colloid and biocolloid transport in homogeneous, water saturated porous media. The results demonstrated that the dispersivity increases very slowly with increasing interstitial velocity, and increases with column length. Furthermore, contrary to earlier results, which were based either on just a few experimental observations or experimental conditions leading to low mass recoveries, dispersivity was positively correlated with colloid particle size. Also, transport experiments were performed with biocolloids (bacteriophages:

  3. Solubility and speciation of actinides in salt solutions and migration experiments of intermediate level waste in salt formations

    International Nuclear Information System (INIS)

    A comprehensive study into the solubility of the actinides americium and plutonium in concentrated salt solutions, the release of radionuclides from various forms of conditioned ILW and the migration behaviour of these nuclides through geological material specific to the Gorleben site in Lower Saxony is described. A detailed investigation into the characterization of four highly concentrated salt solutions in terms of their pH, Eh, inorganic carbon contents and their densities is given and a series of experiments investigating the solubility of standard americium(III) and plutonium(IV) hydroxides in these solutions is described. Transuranic mobility studies for solutions derived from the standard hydroxides through salt and sand have shown the presence of at least two types of species present of widely differing mobility; one migrating with approximately the same velocity as the solvent front and the other strongly retarded. Actinide mobility data are presented and discussed for leachates derived from the simulated ILW in cement and data are also presented for the migration of the fission products in leachates derived from real waste solidified in cement and bitumen. Relatively high plutonium mobilities were observed in the case of the former and in the case of the real waste leachates, cesium was found to be the least retarded. The sorption of ruthenium was found to be largely associated with the insoluble residues of the natural rock salt rather than the halite itself. (orig./RB)

  4. Actinide co-conversion by internal gelation

    International Nuclear Information System (INIS)

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

  5. Chemical compatibility of HLW borosilicate glasses with actinides

    International Nuclear Information System (INIS)

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

  6. The lanthanides and actinides

    International Nuclear Information System (INIS)

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

  7. Lanthanides and actinides in ionic liquids

    OpenAIRE

    Binnemans, Koen

    2007-01-01

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

  8. Actinide chemistry in ionic liquids.

    Science.gov (United States)

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

    2013-04-01

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

  9. THERMODYNAMICS OF THE ACTINIDES

    Energy Technology Data Exchange (ETDEWEB)

    Cunningham, Burris B.

    1962-04-01

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

  10. Overview of actinide chemistry in the WIPP

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-01-01

    inorganic complexants are expected to be carbonate/bicarbonate and hydroxide. There are also organic complexants in TRU waste with the potential to strongly influence actinide solubility. (3) Intrinsic and pseudo-actinide colloid formation - Many actinide species in their expected oxidation states tend to form colloids or strongly associate with non actinide colloids present (e.g., microbial, humic and organic). In this context, the relative importance of actinides, based on the TRU waste inventory, with respect to the potential release of actinides from the WIPP, is greater for plutonium and americium, and to less extent for uranium and thorium. The most important oxidation states for WIPP-relevant conditions are III and IV. We will present an update of the literature on WIPP-specific data, and a summary of the ongoing research related to actinide chemistry in the WIPP performed by the Los Alamos National Laboratory (LANL) Actinide Chemistry and Repository Science (ACRSP) team located in Carlsbad, NM [Reed 2007, Lucchini 2007, and Reed 2006].

  11. PREFACE: Actinides 2009

    Science.gov (United States)

    Rao, Linfeng; Tobin, James G.; Shuh, David K.

    2010-07-01

    This volume of IOP Conference Series: Materials Science and Engineering consists of 98 papers that were presented at Actinides 2009, the 8th International Conference on Actinide Science held on 12-17 July 2009 in San Francisco, California, USA. This conference was jointly organized by Lawrence Livermore National Laboratory and Lawrence Berkeley National Laboratory. The Actinides conference series started in Baden-Baden, Germany (1975) and this first conference was followed by meetings at Asilomar, CA, USA (1981), Aix-en-Provence, France (1985), Tashkent, USSR (1989), Santa Fe, NM, USA (1993), Baden-Baden, Germany (1997), Hayama, Japan (2001), and Manchester, UK (2005). The Actinides conference series provides a regular venue for the most recent research results on the chemistry, physics, and technology of the actinides and heaviest elements. Actinides 2009 provided a forum spanning a diverse range of scientific topics, including fundamental materials science, chemistry, physics, environmental science, and nuclear fuels. Of particular importance was a focus on the key roles that basic actinide chemistry and physics research play in advancing the worldwide renaissance of nuclear energy. Editors Linfeng Rao Lawrence Berkeley National Laboratory (lrao@lbl.gov) James G Tobin Lawrence Livermore National Laboratory (tobin1@llnl.gov) David K Shuh Lawrence Berkeley National Laboratory (dkshuh@lbl.gov)

  12. Release and transport of mobile organic matter and biocolloids: A combined physicochemical and microbiological study

    Science.gov (United States)

    Reichel, Katharina; Schaefer, Sabine; Babin, Doreen; Smalla, Konny; Totsche, Kai Uwe

    2016-04-01

    Biogeochemical interfaces within the aggregate system of soils are "hot spots" of microbial activity and turnover of organic matter. We explore turnover, release and transport of mobile organic matter (MOM), micro-organisms (bio-colloids) and organo-mineral associations using a novel experimental approach employing two-layer columns experiment with matured soil under unsaturated flow conditions. The top layer was spiked with phenanthrene as a tracer for studying the decomposer communities involved in the decomposition of aromatic compounds that derive from lignin in natural systems. Columns were irrigated with artificial rain water with several flow interrupts of different durations. Physicochemical and chemical parameters as well as the microbial community composition were analysed in effluent samples and in soil slices. Release of MOM from the columns was in general controlled by non-equilibrium. Export of total and dissolved organic matter differed significantly in response to the flow interrupts. Effluent comprised organic and organo-mineral components as well as vital competent cells. By molecular biological methods we were even able to show that bacterial consortia exported are rather divers. Depth distribution of the bacterial communities associated with the immobile solid phase indicated high similarities in bacterial communities of the different depth layers and treatments. According to phenanthrene high affinity to the immobile phases, only a small fraction was subject to downstream transport with a strong decrease of the amount residing at the solid phase Our experiments directly prove that intact and competent microorganisms and even communities can be transported under unsaturated flow conditions. Moreover, we found that the dominant carbon source will impact not only the activity of specific microbial taxa but also their mobilization and transport. While total contribution of microbial organism to the mobile organic matter pool seems to be small, the

  13. Complexes of metals with humus substances as natural biocolloids: mechanism and size

    Science.gov (United States)

    Dinu, Marina; Shkinev, Valery; Linnik, Vitaly

    2014-05-01

    Metal complexes with humus substances in the soil are natural biocolloids, which are characterized by the size of the nano- to milli grams. Physical state of the compound functional features humus substances (HS), the nature of metal - all these parameters define different mechanisms transportation of the metal in the soil profile. To assess changes in the composition humus substances complexes with metals and molecular weights humus substances used methods ultrotsentrifugation and filtration (electrochemical and chromatographic methods. Soil samples of gleepodzolic were selected in Hibin (Russia) by layers (0-50 cm) by 5 cm. According to the data within the layers ultrafiltration alkali metals do not stay in any of the fractions and to migrate as the ions (40-50 cm). Alkali- earth metals, on the contrary, delayed a layer ( 2-7 cm), most humified layer, explained by the appearance of active d- orbital of the metal cations, and their greater ability to form complexes than alkali metals. Aluminum content of elements of the subgroup represented by several peaks, mainly in the upper layers of the soil in those areas where the most represented type of fulvic humus substances. High concentration of iron in all studied soil layers. An exception is the 15-35 cm layer which contains humic substance in large quantities compared with fulvic acids, that may explain the decrease in the affinity of the metal to the functional groups and less strong sorption communication mechanism. Metal concentrations of nickel and cobalt are practically unchanged with soil depth. Indicating that almost the same ability to bind to humic and fulvic acids. In samples of 5-8 cm identified reduction of zinc and copper ions in the filtrates from 8 microns to 100 kDa. However, complexes with zinc ions of HS molecular weight less than 100 kDa in all filtrates predominates, particularly fulvic type complexes. Lead ions are predominantly high molecular weight complexes of over 1000 kD, so the filtrate

  14. 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.

  15. 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).

  16. Software for fitting and simulating fate and transport of dense colloids and biocolloids in one-dimensional porous media: Re-introducing ColloidFit.

    Science.gov (United States)

    Katzourakis, Vasileios; Chrysikopoulos, Constantinos

    2016-04-01

    The present work re-introduces ColloidFit, which is an autonomous, modular, multipurpose fitting software for dense colloid and biocolloid transport phenomena in porous media. The initial version of ColloidFit, introduced by Sim and Chrysikopoulos (1995), was substantially improved and combined with a relatively intuitive and easy to use graphical user interface. The re-introduced ColloidFit can simulate the migration of suspended colloid or biocolloid particles in one-dimensional, water saturated, homogeneous porous media with uniform flow, accounting for non-equilibrium attachment onto the solid matrix, as well as gravitational effects. Furthermore, the improved ColloidFit software employs a variety of non-equilibrium, linear and nonlinear models for the simulation of colloid attachment onto a solid matrix under batch experimental conditions. The re-introduced ColloidFit uses the state of the art fitting software "Pest" to estimate unknown model parameter values, together with their 95% confidence intervals. Pest is a model-independent parameter estimation software capable of adjusting model parameters, so that discrepancies between model-generated data and the corresponding experimental measurements are reduced to a user preselected minimum. The fitting process is graphed and displayed in real time. The user is allowed to overview every step of the fitting progress, and if needed to change the initial parameter values. The re-introduced ColloidFit software is expected to make the fitting process of colloid and biocolloid transport data, just a simple task.

  17. In-situ mineralization of actinides with phytic acid

    International Nuclear Information System (INIS)

    A new approach to the remediation of actinide contamination is described. A hydrolytically unstable organophosphorus compound, phytic acid, is introduced into the contaminated environment. In the short term (up to several hundred years), phytate acts as a cation exchanger to absorb mobile actinide ions from ground waters. Ultimately, phytate decomposes to release phosphate and promote the formation of insoluble phosphate mineral phases, considered an ideal medium to immobilize actinides, as it forms compounds with the lowest solubility of any candidate mineral species. This overview will discuss the rate of hydrolysis of phytic acid, the formation of lanthanide/actinide phosphate mineral forms, the cation exchange behavior of insoluble phytate, and results from laboratory demonstration of the application to soils from the Fernald site

  18. Device for Detecting Actinides, Method for Detecting Actinides

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, Fred J.; Wilkins-Stevens, Priscilla

    1998-10-29

    A heavy metal detector is provided comprising a first molecule and a second molecule, whereby the first and second molecules interact in a predetermined manner; a first region on the first molecule adapted to interact with an actinide; and a second region on the second molecule adapted to interact with the actinide, whereby the interactions of the actinide with the regions effect the predetermined manner of interaction between the molecules.

  19. The electrochemical properties of actinide amalgams

    International Nuclear Information System (INIS)

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

  20. Actinide separation chemistry in nuclear waste streams and materials

    International Nuclear Information System (INIS)

    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

  1. Recovering actinide values

    International Nuclear Information System (INIS)

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

  2. Actinides: why are they important biologically

    International Nuclear Information System (INIS)

    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

  3. Photoelectron spectra of actinide compounds

    International Nuclear Information System (INIS)

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

  4. Optical techniques for actinide research

    International Nuclear Information System (INIS)

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

  5. Concentration of actinides in the food chain

    International Nuclear Information System (INIS)

    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)

  6. Calorimetric assay of minor actinides

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-12-31

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

  7. Calorimetric assay of minor actinides

    International Nuclear Information System (INIS)

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

  8. Environmental research on actinide elements

    International Nuclear Information System (INIS)

    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

  9. The electrochemical properties of actinide amalgams

    International Nuclear Information System (INIS)

    Selection of the values of standard potentials of An actinides and their amalgams was made. On the basis of the data obtained energy characteristics of alloy formation processes in the systems An-Hg were calculated and analyzed. It is ascertained that the properties of f-element solutions in mercury are similar to those of alkali and alkaline-earth metal amalgams with the only difference, i.e. in case of active metals of group 3 the number of realized charge value of ionic frames in condensed phase increases

  10. Thermodynamic properties of actinide complexes. II. Thorium(IV)--acetate system. [Formation of thorium(IV)-acetate complexes in aqueous perchlorate medium

    Energy Technology Data Exchange (ETDEWEB)

    Portanova, R.; Di Bernardo, P.; Traverso, O.; Mazzocchin, G.A.; Magon, L.

    1975-10-01

    The changes in free energy, enthalpy and entropy for the formation of thorium(IV)--acetate complexes have been determined at 25/sup 0/C and in 1.00 M aqueous perchlorate-medium. All five complexes formed, are found to be stabilized by a large gain of entropy. The marked increase in the values of ..delta..H/sub j/ and ..delta..S/sub j/, relative to the third step of complexation has been explained in terms of a coordination change.

  11. 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.

  12. Actinides and Life's Origins.

    Science.gov (United States)

    Adam, Zachary

    2007-12-01

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

  13. Fabrication of actinide mononitride fuel

    International Nuclear Information System (INIS)

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

  14. Actinide geochemistry: from the molecular level to the real system.

    Science.gov (United States)

    Geckeis, Horst; Rabung, Thomas

    2008-12-12

    Geochemical processes leading to either mobilization or retention of radionuclides in an aquifer system are significantly influenced by their interaction with rock, sediment and colloid surfaces. Therefore, a sound safety assessment of nuclear waste disposal requires the elucidation and quantification of those processes. State-of-the-art analytical techniques as e.g. laser- and X-ray spectroscopy are increasingly applied to study solid-liquid interface reactions to obtain molecular level speciation insight. We have studied the sorption of trivalent lanthanides and actinides onto aluminium oxides, hydroxides and purified clay minerals by the time-resolved laser fluorescence spectroscopy and X-ray-absorption spectroscopy. Chemical constitution and structure of surface bound actinides are proposed based on spectroscopic information. Open questions still remain with regard to the exact nature of mineral surface ligands and the mineral/water interface. Similarities of spectroscopic data obtained for M(III) sorbed onto gamma-alumina, and clay minerals suggest the formation of very comparable inner-sphere surface complexes such as S-O-An(III)(OH)x(2-x)(H2O)5-x at pH > 5. Those speciation data are found consistent with those predicted by surface complexation modelling. The applicability of data obtained for pure mineral phases to actinide sorption onto heterogeneously composed natural clay rock is examined by experiments and by geochemical modelling. Good agreement of experiment and model calculations is found for U(VI) and trivalent actinide/lanthanide sorption to natural clay rock. The agreement of spectroscopy, geochemical modelling and batch experiments with natural rock samples and purified minerals increases the reliability in model predictions. The assessment of colloid borne actinide migration observed in various laboratory and field studies calls for detailed information on actinide-colloid interaction. Kinetic stabilization of colloid bound actinides can be due

  15. Research on the chemical speciation of actinides

    International Nuclear Information System (INIS)

    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

  16. 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)

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

    International Nuclear Information System (INIS)

    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 P2W17O6110- or SiW11O398- 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.)

  18. Program and presentations of the 33th Actinide Days

    International Nuclear Information System (INIS)

    The 'Journees des Actinides' (JDA) is an annual conference which provides a forum for discussions on all aspects related to the chemical and physical properties of the actinides. At the 2003 meeting, mainly the following properties were discussed of actinides and a number of actinide compounds and complexes: crystal structure, crystal-phase transformations and transformation temperatures; electrical properties including superconductivity and superconducting transition temperatures; magnetic properties; specific heat and other thermodynamic properties; electronic structure, especially in condensed matter; chemical and physico-chemical properties. The relevant experimental techniques were also dealt with, such as neutron diffraction; X-ray diffraction, in particular using synchrotron radiation; photoemission techniques, electron microscopy and spectroscopy, etc. Altogether 96 contributions were presented, of which 42 were oral presentations and 54 poster presentations. A program of the meeting and texts of both type of presentations were published in electronic form in the PDF format. All contributions were inputted to INIS; the full text of the program and the presentations has been incorporated into the INIS collection of non-conventional literature on CD-ROM. (A.K.)

  19. Synthesis and structural characterization of actinide oxalate compounds

    International Nuclear Information System (INIS)

    Oxalic acid is a well-known reagent to recover actinides thanks to the very low solubility of An(IV) and An(III) oxalate compounds in acidic solution. Therefore, considering mixed-oxide fuel or considering minor actinides incorporation in ceramic fuel materials for transmutation, oxalic co-conversion is convenient to synthesize mixed oxalate compounds, precursors of oxide solid solutions. As the existing oxalate single crystal syntheses are not adaptable to the actinide-oxalate chemistry or to their manipulation constrains in gloves box, several original crystal growth methods were developed. They were first validate and optimized on lanthanides and uranium before the application to transuranium elements. The advanced investigations allow to better understand the syntheses and to define optimized chemical conditions to promote crystal growth. These new crystal growth methods were then applied to a large number of mixed An1(IV)-An2(III) or An1(IV)-An2(IV) systems and lead to the formation of the first original mixed An1(IV)-An2(III) and An1(IV)-An2(IV) oxalate single crystals. Finally thanks to the first thorough structural characterizations of these compounds, single crystal X-ray diffraction, EXAFS or micro-RAMAN, the particularly weak oxalate-actinide compounds structural database is enriched, which is essential for future studied nuclear fuel cycles. (author)

  20. Experimental Evaluation of Actinide Transport in a Fractured Granodiorite

    Energy Technology Data Exchange (ETDEWEB)

    Dittrich, Timothy M. [Los Alamos National Laboratory; Reimus, Paul W. [Los Alamos National Laboratory

    2015-03-16

    The objective of this study was to demonstrate and evaluate new experimental methods for quantifying the potential for actinide transport in deep fractured crystalline rock formations. We selected a fractured granodiorite at the Grimsel Test Site (GTS) in Switzerland as a model system because field experiments have already been conducted with uranium and additional field experiments using other actinides are planned at the site. Thus, working on this system provides a unique opportunity to compare lab experiment results with fieldscale observations. Rock cores drilled from the GTS were shipped to Los Alamos National Laboratory, characterized by x-ray diffraction and microscopy, and used in batch sorption and column breakthrough experiments. Solutions with pH 6.8 and 8.8 were tested. Solutions were switched to radionuclide-free synthetic Grimsel groundwater after near-steady actinide/colloid breakthrough occurred in column experiments. We are currently evaluating actinide adsorption/desorption rates as a function of water chemistry (initial focus on pH), with future testing planned to evaluate the influence of carbonate concentrations, flow rates, and mineralogy in solutions and suspensions with bentonite colloids. (auth)

  1. Actinides recycling assessment in a thermal reactor

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2009-12-01

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

  3. Actinide recovery techniques utilizing electromechanical processes

    International Nuclear Information System (INIS)

    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

  4. Actinide Waste Forms and Radiation Effects

    Science.gov (United States)

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

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

  5. Long-term plant availability of actinides

    International Nuclear Information System (INIS)

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

  6. Chemistry of actinides and fission products

    International Nuclear Information System (INIS)

    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

  7. Spin and orbital moments in actinide compounds

    DEFF Research Database (Denmark)

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

    1991-01-01

    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...

  8. Prompt fission neutron spectrum of actinides

    Energy Technology Data Exchange (ETDEWEB)

    Capote, R. [International Atomic Energy Agency, Vienna (Austria); Chen, Y. -J. [China Institute of Atomic Energy, Beijing (China); Hambsch, F. J. [European Commission, Joint Research Centre - IRRM, Geel (Belgium); Jurado, B. [CENBG, CNRS/IN2P3, Gradignan (France); Kornilov, N. [Ohio Univ., Athens, OH (United States); Lestone, J. P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Litaize, O. [CEA, DEN, DER, SPRC, Saint-Paul-Lez-Durance (France); Morillon, B. [CEA, DAM, DIF, Arpajon (France); Neudecker, D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Oberstedt, S. [European Commission, Joint Research Centre - IRRM, Geel (Belgium); Ohsawa, T. [Kinki Univ., Osaka-fu (Japan); Otuka, N. [International Atomic Energy Agency, Vienna (Austria); Pronyaev, V. G. [Institute of Physics and Power Engineering, Obninsk (Russian Federation); Saxena, A. [Bhabha Atomic Research Centre, Mumbai (India); Schmidt, K. H. [CENBG, CNRS/IN2P3, Gradignan (France); Serot, O. [CEA, DEN, DER, SPRC, Saint-Paul-Lez-Durance (France); Shcherbakov, O. A. [Petersburg Nuclear Physics Institute of NRC " Kurchatov Institute" , Gatchina (Russian Federation); Shu, N. -C. [China Institute of Atomic Energy, Beijing (China); Smith, D. L. [Argonne National Lab. (ANL), Argonne, IL (United States); Talou, P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Trkov, A. [International Atomic Energy Agency, Vienna (Austria); Tudora, A. C. [Univ. of Bucharest, Magurele (Romania); Vogt, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Univ. of California, Davis, CA (United States); Vorobyev, A. S. [Petersburg Nuclear Physics Institute of NRC " Kurchatov Institute" , Gatchina (Russian Federation)

    2016-01-06

    Here, the energy spectrum of prompt neutron emitted in fission (PFNS) plays a very important role in nuclear science and technology. A Coordinated Research Project (CRP) "Evaluation of Prompt Fission Neutron Spectra of Actinides" was established by the IAEA Nuclear Data Section in 2009, with the major goal to produce new PFNS evaluations with uncertainties for actinide nuclei.

  9. 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....

  10. Gross actinide preconcentration using phosphonate-based ligand and cloud point extraction

    International Nuclear Information System (INIS)

    A procedure for the effective separation and determination of the most abundant actinides relevant to the nuclear industry (U, Th, Np, Pu and Am) was developed based on cloud point extraction (CPE) using H2DEH[MDP] (P,P-di-(2-ethylhexyl) methanediphosphonic acid) as a ligand. The extractability of actinides with varying concentrations of nitric acid and hydrochloric acid were assessed. The robustness of the method was demonstrated for environmental matrices such as reference materials and spiked liquid samples for the quantification of the gross actinide content. This analytical strategy may replace traditional sample preparation techniques used in radiological methods for gross measurements of radioactivity, and may act as a rapid screening tool in emergency situations. The developed method is a greener alternative to common radiochemical sample preparation techniques such as co-precipitation or evaporation. The formation of a small-volume surfactant-rich phase containing the complexed actinides enables rapid, highly selective and great enrichment of the analytes in this phase. The proposed method shows good extraction and separation yield compared to existing methods, since the surfactant-rich phase is soluble in water and can therefore be redispersed quantitatively in a medium compatible with mass spectrometry while providing fast isolation of the actinide content. Separation of actinides can be achieved after by wet ashing of the surfactant-rich phase obtained by CPE if coupled to the proper radiochemical separation scheme. (author)

  11. Electrochemical separation of actinides and fission products in molten salt electrolyte

    Science.gov (United States)

    Gay, R. L.; Grantham, L. F.; Fusselman, S. P.; Grimmett, D. L.; Roy, J. J.

    1995-09-01

    Molten salt electrochemical separation may be applied to accelerator-based conversion (ABC) and transmutation systems by dissolving the fluoride transport salt in LiCl-KCl eutectic solvent. The resulting fluoride-chloride mixture will contain small concentrations of fission product rare earths (La, Nd, Gd, Pr, Ce, Eu, Sm, and Y) and actinides (U, Np, Pu, Am, and Cm). The Gibbs free energies of formation of the metal chlorides are grouped advantageously such that the actinides can be deposited on a solid cathode with the majority of the rare earths remaining in the electrolyte. Thus, the actinides are recycled for further transmutation. Rockwell and its partners have measured the thermodynamic properties of the metal chlorides of interest (rare earths and actinides) and demonstrated separation of actinides from rare earths in laboratory studies. A model is being developed to predict the performance of a commercial electrochemical cell for separations starting with PUREX compositions. This model predicts excellent separation of plutonium and other actinides from the rare earths in metal-salt systems.

  12. Testing actinide fission yield treatment in CINDER90 for use in MCNP6 burnup calculations

    International Nuclear Information System (INIS)

    Most of the development of the MCNPX/6 burnup capability focused on features that were applied to the Boltzman transport or used to prepare coefficients for use in CINDER90, with little change to CINDER90 or the CINDER90 data. Though a scheme exists for best solving the coupled Boltzman and Bateman equations, the most significant approximation is that the employed nuclear data are correct and complete. Thus, the CINDER90 library file contains 60 different actinide fission yields encompassing 36 fissionable actinides (thermal, fast, high energy and spontaneous fission). Fission reaction data exists for more than 60 actinides and as a result, fission yield data must be approximated for actinides that do not possess fission yield information. Several types of approximations are used for estimating fission yields for actinides which do not possess explicit fission yield data. The objective of this study is to test whether or not certain approximations of fission yield selection have any impact on predictability of major actinides and fission products. Further we assess which other fission products, available in MCNP6 Tier 3, result in the largest difference in production. Because the CINDER90 library file is in ASCII format and therefore easily amendable, we assess reasons for choosing, as well as compare actinide and major fission product prediction for the H. B. Robinson benchmark for, three separate fission yield selection methods: (1) the current CINDER90 library file method (Base); (2) the element method (Element); and (3) the isobar method (Isobar). Results show that the three methods tested result in similar prediction of major actinides, Tc-99 and Cs-137; however, certain fission products resulted in significantly different production depending on the method of choice

  13. 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.

  14. Actinide ion sensor for pyroprocess monitoring

    Science.gov (United States)

    Jue, Jan-fong; Li, Shelly X.

    2014-06-03

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

  15. Ionic Interactions in Actinide Tetrahalides

    Science.gov (United States)

    Akdeniz, Z.; Karaman, A.; Tosi, M. P.

    2001-05-01

    We determine a model of the ionic interactions in AX 4 compounds (where A is an atom in the actinide series from Th to Am and X = F, Cl, Br or I) by an analysis of data on the static and dynamic structure of their molecular monomers. The potential energy function that we adopt is taken from earlier work on rare-earth trihalides [Z. Akdeniz, Z. Q q e k and M. P. Tosi, Z. Naturforsch. 55a, 861 (2000)] and in particular allows for the electronic polarizability of the actinide ion. This polarizability quantitatively determines the antisymmetric-bending vibrational mode, but its magnitude remains compatible with a symmetric tetrahedral shape of the molecule at equilibrium. The fluorides have an especially high degree of ionic character, and the interionic-force parameters for each halide of the U, Np, Pu and Am series show regular trends, suggesting that extrapolations to the other transuranic-element halides may usefully be made. The Th compounds show some deviations from these trends, and the interionic-force model that we determine for ThCl4 differs somewhat from that obtained in a previous study. We therefore return on the evaluation of the relative stability of charged oligomers of ThCl4 and ZrCl4 and find confirmation of our earlier results on this problem.

  16. The ALMR actinide burning system

    International Nuclear Information System (INIS)

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

  17. Covariance evaluation for actinide nuclear data in JENDL-4

    International Nuclear Information System (INIS)

    Full text: The JENDL-4.0 was released in March 2010. It provides neutron nuclear data for 79 actinides from Ac to Fm. All of the actinides include covariance data. The covariance data were evaluated for reaction cross sections, resonance parameters, angular distributions of elastic scattering, average number of neutrons per fission, and prompt fission neutron spectra. They were deduced basically based on the consistent methodologies with the nuclear data evaluations. Statistical processing of experimental data sometimes gives unacceptably small uncertainty compared with experimental data. They may arise from ignoring unknown errors and correlation of experimental data and also from the modeling errors. The covariance data obtained from statistical estimation using the least-squares method were sometimes modified to be reasonable taking account of consistency with dispersion of experimental data, which may reflect the uncertainties of the data. For the fast neutron fission cross sections of 6 major actinides of 233,235,238U and 239,240,241Pu were evaluated simultaneously using both cross section and their ratio data with the least- squares fitting code SOK. It gave the covariance matrices that have cross correlations between different nuclei included in the analyses. For the minor actinide, the least-squares fitting code GMA was used for fission cross section evaluation for fast neutrons. The covariance data were obtained from the calculations at the same time. For other reaction cross sections, covariance matrices were evaluated using CCONE-KALMAN code system. Sensitivities to model parameters were calculated by CCONE code and used to estimate covariance matrices of the parameters with KALMAN code. Covariance matrices for other data such as resonance parameters and average numbers of fission neutrons were also evaluated based on experimental data. The evaluated covariance data were compiled to the ENDF-6 format files and included in JENDL-4.

  18. Investigations of actinides in the context of final disposal of high-level radioactive waste. Trivalent actinides in aqueous solution

    International Nuclear Information System (INIS)

    The speciation of redox sensitive trivalent actinides Pu(III), Np(III), and U(III) has been studied in aqueous solution. The redox preparation, stabilization, and speciation of these trivalent actinides in aqueous systems are discussed here. The reductants investigated were rongalite, hydroxylamine hydrochloride, and acetohydroxamic acid and the An(III) species have been characterized by UV-Vis and XANES spectroscopy. The results show that the effectiveness of stabilization decreases generally in the order Pu(III) > Np(III) > U(III) and that the effectiveness of each reducing agent depends on the experimental conditions. More than 80 % of Pu(III) aquo species have been stabilized up to pH 5.5, whereas the Np(III) aquo ion could be stabilized in a pH range 0-2.5, and U(III) aquo ion is sufficiently stable at pH 1.0 and below over time periods suitable for experiments. However, this study gives a basis for the characterisation of the trivalent lighter actinides involved in complexation, sorption, and solid formation reactions in the future. (author)

  19. Experimental studies of actinides in molten salts

    International Nuclear Information System (INIS)

    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

  20. Electronic structure and magnetic properties of actinides

    International Nuclear Information System (INIS)

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

  1. 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.

  2. Recovery of actinides from actinide-aluminium alloys by chlorination: Part II

    OpenAIRE

    Soucek, Pavel; Cassayre, Laurent; Eloirdi, Rachel; Malmbeck, Rikard; Meier, Roland; Nourry, Christophe; Claux, Benoit; Glatz, Jean-Paul

    2014-01-01

    International audience; A chlorination route is being investigated for recovery of actinides from actinide-aluminium alloys, which originate from pyrochemical recovery of actinides from spent metallic nuclear fuel by electrochemical methods in molten LiCl-KCl. In the present work, the most important steps of this route were experimentally tested using U-Pu-Al alloy prepared by electrodeposition of U and Pu on solid aluminium plate electrodes. The investigated processes were vacuum distillatio...

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

    OpenAIRE

    Cassayre, Laurent; Soucek, Pavel; Mendes, Eric; Malmbeck, Rikard; Nourry, Christophe; Eloirdi, Rachel; Glatz, Jean-Paul

    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, chlorina...

  4. 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.

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

    International Nuclear Information System (INIS)

    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

  6. Actinide recovery from pyrochemical residues

    International Nuclear Information System (INIS)

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

  7. Preparation of actinide targets by electrodeposition

    Science.gov (United States)

    Trautmann, N.; Folger, H.

    1989-10-01

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

  8. Actinide research to solve some practical problems

    International Nuclear Information System (INIS)

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

  9. Electronic structure and correlation effects in actinides

    Energy Technology Data Exchange (ETDEWEB)

    Albers, R.C.

    1998-12-01

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

  10. 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).

  11. 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.

  12. Heavy element and actinide decay data: UKHEDD-2 data files

    International Nuclear Information System (INIS)

    A re-evaluation has been made of the decay data for 126 heavy elements and actinides of direct application in nuclear fuel cycle calculations. Computer-based data files have been produced in ENDF/B-VI format, including lists of the references used to produce the proposed decay schemes and comments that identify their inadequacies. These evaluated data include half-lives, average decay energies, branching ratios, alpha, beta and gamma-ray energies and emission probabilities, internal conversion coefficients, spontaneous fission decay data and all associated uncertainties. (author)

  13. Superconductivity in rare earth and actinide compounds

    International Nuclear Information System (INIS)

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

  14. The Actinide Transition Revisited by Gutzwiller Approximation

    Science.gov (United States)

    Xu, Wenhu; Lanata, Nicola; Yao, Yongxin; Kotliar, Gabriel

    2015-03-01

    We revisit the problem of the actinide transition using the Gutzwiller approximation (GA) in combination with the local density approximation (LDA). In particular, we compute the equilibrium volumes of the actinide series and reproduce the abrupt change of density found experimentally near plutonium as a function of the atomic number. We discuss how this behavior relates with the electron correlations in the 5 f states, the lattice structure, and the spin-orbit interaction. Our results are in good agreement with the experiments.

  15. Lattice effects in the light actinides

    Energy Technology Data Exchange (ETDEWEB)

    Lawson, A.C.; Cort, B.; Roberts, J.A.; Bennett, B.I.; Brun, T.O.; Dreele, R.B. von [Los Alamos National Lab., NM (United States); Richardson, J.W. Jr. [Argonne National Lab., IL (United States)

    1998-12-31

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

  16. 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.

  17. Evaluation of actinide partitioning and transmutation

    International Nuclear Information System (INIS)

    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

  18. Recent progress in actinide borate chemistry.

    Science.gov (United States)

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

    2011-10-21

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

  19. Results of coupled channels calculations for the neutrons cross sections of a set of actinide nuclei

    International Nuclear Information System (INIS)

    This report gathers recents results of neutrons interactions with the following actinide nuclei: 230Th, 232Th, 234U, 238U, 242Pu, 246Cm and 252Cf from the use of the coupled channels optical model. Tabulations of the following quantities are given in Annexe: total, direct elastic and inelastic scattering (integrated and differential), and compound nucleus formation cross sections; ground state generalized transmission coefficients needed to calculate the cross sections of partial compound nucleus processes. This work was carried out within the framework of the IAEA-NDS Coordinated Research Programme on the Intercomparison of Actinide Neutron Cross Section Evaluations

  20. MINOR ACTINIDE SEPARATIONS USING ION EXCHANGERS OR IONIC LIQUIDS

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-09-20

    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.

  1. Reversible optical sensor for the analysis of actinides in solution; Capteur optique reversible pour l'analyse des actinides en solution

    Energy Technology Data Exchange (ETDEWEB)

    Lesage, B.; Picard, S. [CEA Marcoule, Dept. de Radiochimie et Procedes, Service de Chimie des Procedes de Separation, Lab. de Chimie des Actinides, 30 (France); Serein-Spirau, F.; Lereporte, J.P. [Ecole Nationale Superieure de Chimie de Montpellier (ENSCM), CNRS UMR 5076, Lab. Heterochimie Moleculaire et Macromoleculaire, 34 - Montpellier (France)

    2007-07-01

    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{sub 2}W{sub 17}O{sub 61}{sup 10-} or SiW{sub 11}O{sub 39}{sup 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.)

  2. Solubility of actinide surrogates in nuclear glasses

    International Nuclear Information System (INIS)

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

  3. Waste disposal aspects of actinide separation

    International Nuclear Information System (INIS)

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

  4. Hybridization effects in selected actinides and their compounds

    Science.gov (United States)

    El-Khatib, Sami T.

    Many actinide systems exhibit 'unusual' phenomena that differ from the normal text-book behavior. This occurs because the 5f electrons of the actinides and their compounds experience a delicate balance between local-moment and itinerant magnetism. It is well established that strong-electron correlations affect the different properties in such systems. Even though the actinides and their compounds have been extensively studied in recent decades, both experimentally and theoretically, to date, no complete understanding of the full range of their properties has been achieved. My thesis focuses mainly on understanding the role of 5f electrons and their interactions with the electron states of the surrounding ligands. Particularly, the effect of the 5f-ligand hybridization in the development of bulk properties is investigated. The experimental studies utilized macroscopic techniques, such as magnetization, electrical-resistivity, specific-heat and resonant-ultrasound-spectroscopy measurements, as well as microscopic techniques, such as neutron-diffraction and muon-spin-resonance studies. The results are used to disentangle the importance of direct 5f--5f overlap and 5 f-ligand hybridization. The following features have been investigated in this thesis: (a) the dual nature of hybridization effects (magnetic moment reduction vs. exchange mediation) was studied for two isostructural uranium compounds U2Pd2Sn and U2Ni2 In; (b) the formation of complex magnetic structures and its connection to the hybridization effects was studied for UCuSn, UPdSn and UPdGe; (c) the tuning of the hybridization to critical values through substitutions was attempted for two single crystals of UCoAl1-xSn x and UNi1-xRh xAl alloys; (d) the effects of compositional deficiencies was studied for the copper-deficient compound in UCu1.5Sn 2; and finally, (e) the influence of strong electron correlations on the elastic properties was studied in the case of alpha-Pu.

  5. Minior Actinide Doppler Coefficient Measurement Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Nolan E. Hertel; Dwayne Blaylock

    2008-04-10

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

  6. Research on Actinides in Nuclear Fuel Cycles

    International Nuclear Information System (INIS)

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

  7. Coordination chemistry for new actinide separation processes

    International Nuclear Information System (INIS)

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

  8. Coordination polymers: trapping of radionuclides and chemistry of tetravalent actinides (Th, U) carboxylates

    International Nuclear Information System (INIS)

    The use of nuclear energy obviously raises the question of the presence of radionuclides in the environment. Currently, their mitigation is a major issue associated with nuclear chemistry. This thesis focuses on both the trapping of radionuclides by porous solids called Metal-Organic Frameworks (MOF) and the crystal chemistry of the carboxylate of tetravalent actinides (AnIV). The academic knowledge of the reactivity of carboxylate of AnIV could help the understanding of actinides speciation in environment. We focused on the sequestration of iodine by aluminum based MOF. The functionalization (electron-donor group) of the MOF drastically enhances the iodine capture capacity. The removal of light actinides (Th and U) from aqueous solution was also investigated as well as the stability of (Al)-MOF under γ radiation. More than twenty coordination polymers based on tetravalent actinides have been synthesized and characterized by single crystal X-ray diffraction. The use of controlled hydrolysis promotes the formation of coordination polymers exhibiting polynuclear cluster ([U4], [Th6], [U6] and [U38]). In order to understand the formation of the largest cluster, the ex-situ study of the solvo-thermal synthesis of compound {U38} has also been investigated. (author)

  9. Actinide phosphonate complexes in aqueous solutions

    International Nuclear Information System (INIS)

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

  10. Sequential analysis of selected actinides in urine

    International Nuclear Information System (INIS)

    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)

  11. 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 reduc...... 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....

  12. Actinide elements in aquatic and terrestrial environments

    International Nuclear Information System (INIS)

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

  13. 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.)

  14. Actinide and fission product separation and transmutation

    International Nuclear Information System (INIS)

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

  15. Actinide recycle in LMFBRs as a waste management alternative

    Energy Technology Data Exchange (ETDEWEB)

    Beaman, S.L.

    1979-08-21

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

  16. Hollow fibre supported liquid membrane based separations of actinides

    International Nuclear Information System (INIS)

    Renaissance in nuclear energy is poised to make a significant contribution to the diversification of clean energy resources and to reduce the burden of CO2 in atmosphere. Its sustainability lies in using nature's mineral resources in an efficient and environmentally friendly way. One of the major challenges in the nuclear energy programme has, however, been the management of radioactive waste in a manner which allays apprehensions about its adverse impact on the environment. Innovative approaches are being devised internationally to treat spent nuclear fuel as a source of valuables. Separation of long-lived radionuclides such as actinides and fission products from high level radioactive waste is a challenging task for the chemists working on the reprocessing and waste management processes involved at the tail end of nuclear fuel cycle. Amongst the various separation techniques, liquid membrane based separation methods are becoming increasingly popular due to factors such as ligand economy, high efficiency and low power consumption. Techniques such as emulsion liquid membrane and hollow fibre based non-dispersive solvent extraction methods are reported to be more efficient than the solvent extraction based separation methods which have limitations of emulsion/third phase or crud formation. In the present article, an attempt has been made to review the work carried out internationally as well as in the author's laboratory on liquid membrane based actinides separations during last few years with a particular focus on the use of hollow fibre supported liquid membranes. (author)

  17. 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.)

  18. Treatment of actinide-containing organic waste

    International Nuclear Information System (INIS)

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

  19. Report of the panel on inhaled actinides

    International Nuclear Information System (INIS)

    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

  20. Actinide measurements by AMS using fluoride matrices

    Science.gov (United States)

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

    2015-10-01

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

  1. Actinide and fission product partitioning and transmutation

    International Nuclear Information System (INIS)

    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.)

  2. Rapid determination of actinides in asphalt samples

    International Nuclear Information System (INIS)

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

  3. Electronic Structure of the Actinide Metals

    DEFF Research Database (Denmark)

    Johansson, B.; Skriver, Hans Lomholt

    1982-01-01

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

  4. Placental transfer of plutonium and other actinides

    International Nuclear Information System (INIS)

    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)

  5. Method for decontamination of nickel-fluoride-coated nickel containing actinide-metal fluorides

    Science.gov (United States)

    Windt, Norman F.; Williams, Joe L.

    1983-01-01

    The invention is a process for decontaminating particulate nickel contaminated with actinide-metal fluorides. In one aspect, the invention comprises contacting nickel-fluoride-coated nickel with gaseous ammonia at a temperature effecting nickel-catalyzed dissociation thereof and effecting hydrogen-reduction of the nickel fluoride. The resulting nickel is heated to form a melt and a slag and to effect transfer of actinide metals from the melt into the slag. The melt and slag are then separated. In another aspect, nickel containing nickel oxide and actinide metals is contacted with ammonia at a temperature effecting nickel-catalyzed dissociation to effect conversion of the nickel oxide to the metal. The resulting nickel is then melted and separated as described. In another aspect nickel-fluoride-coated nickel containing actinide-metal fluorides is contacted with both steam and ammonia. The resulting nickel then is melted and separated as described. The invention is characterized by higher nickel recovery, efficient use of ammonia, a substantial decrease in slag formation and fuming, and a valuable increase in the service life of the furnace liners used for melting.

  6. 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.

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

    International Nuclear Information System (INIS)

    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.

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

    Science.gov (United States)

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

    1992-01-01

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

  9. Actinides sorption onto hematite. Experimental data, surface complexation modeling and linear free energy relationship

    Energy Technology Data Exchange (ETDEWEB)

    Romanchuk, Anna Y.; Kalmykov, Stephan N. [Lomonosov Moscow State Univ., Moscow (Russian Federation). Dept. of Chemistry

    2014-07-01

    The sorption of actinides in different valence states - Am(III), Th(IV), Np(V) and U(VI) onto hematite have been revisited with the special emphasis on the equilibrium constants of formation of surface species. The experimental sorption data have been treated using surface complexation modeling from which the set of new values of equilibrium constants were obtained. Formation of inner sphere monodentate surface species adequately describes the pH-sorption edges for actinide ions indicative the ionic electrostatic nature of bonding with small or no covalency contribution. The linear free energy relationship representing the correlation between the hydrolysis constants and surface complexation constants has been developed for various cations including K(I), Li(I), Na(I), Ag(I), Tl(I), Sr(II), Cu(II), Co(II), La(III), Eu(III), Ga(III), Am(III), Th(IV), Np(V), U(VI). (orig.)

  10. Minor actinide transmutation on PWR burnable poison rods

    International Nuclear Information System (INIS)

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

  11. Criticality analysis of aggregations of actinides from commerical nuclear waste in geological storage

    International Nuclear Information System (INIS)

    An underground nuclear-waste terminal-storage facility for either spent fuel elements or high level waste from a reprocessing plant will contain large amounts of fissionable actinides. Such a facility must be designed to preclude the concentration of these isotopes into a critical mass. Information on the critical masses of the various isotopes present in spent fuel or high level waste is required as part of such a design effort. This study provides this information. The results of this study will be used, in conjunction with geologic transport rates of the actinide compounds, to estimate mass formation probabilities in waste repositories. A computational model was developed as part of the study to perform criticality calculations rapidly and efficiently and to produce tables and plots of actinide concentration in geologic material versus critical mass. The criticality model uses a discrete ordinates approximation to neutron transport theory and treats six energy groups and spherical geometry. Neutron cross sections were obtained from ENDF/B-IV or ENDF/B-V cross section libraries. Critical masses calculated with the computational model were checked against experimental values and against more detailed calculational values and were found to be from 30 percent less to 10 percent greater. Critical mass calculations were made for five waste types, five waste ages, five actinide elements, and four geologic compositions. Minimum critical masses were calculated for over 400 combinations of the above variables. The relative importance for criticality of the various actinides and waste types is presented in terms of the number of possible critical masses per waste container

  12. Microbial Transformations of Actinides and Other Radionuclides

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-01-07

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

  13. Interaction of actinide cations with synthetic polyelectrolytes

    International Nuclear Information System (INIS)

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

  14. 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.)

  15. Actinides: from heavy fermions to plutonium metallurgy

    International Nuclear Information System (INIS)

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

  16. Actinide and fission product partitioning and transmutation

    International Nuclear Information System (INIS)

    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.)

  17. 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.)

  18. Successive change regularity of actinide properties with atomic number

    International Nuclear Information System (INIS)

    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 f7n-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

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

    Energy Technology Data Exchange (ETDEWEB)

    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 ..mu..g 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.

  20. Nuclear data for plutonium and minor actinides

    International Nuclear Information System (INIS)

    Some experience in the usage of different evaluations of neutron constants for plutonium isotopes and minor actinides (MA) is described. That experience was obtained under designing the ABBN-93 group data set which nowadays is used widely for neutronics calculations of different cores with different spectrum and shielding. Under testing of the ABBN-93 data set through different integral and macroscopic experiments the main attention was paid to fuel nuclides and cross sections for MA practically did not verify. That gave an opportunity to change MA nuclear data for more modern without verification of the hole system. This desire appeared with new data libraries JENDL-3.2, JEF-2.2 and ENDF/B-6.2, which was not accessible under designing the ABBN-93. At the same time with the reevaluation of the basic MA nuclear data the ABBN-93 and the library FOND-2 of evaluated nuclear data files, which used as the basis for retrieving of the ABBN-93 data, were added with not very important MA data. So the FOND-2 library nowadays contents nuclear data files for all actinides with the half-life time more 1 day and also those MA which produce long-life actinides

  1. Recovery of actinides from actinide-aluminium alloys by chlorination: Part II

    Science.gov (United States)

    Souček, P.; Cassayre, L.; Eloirdi, R.; Malmbeck, R.; Meier, R.; Nourry, C.; Claux, B.; Glatz, J.-P.

    2014-04-01

    A chlorination route is being investigated for recovery of actinides from actinide-aluminium alloys, which originate from pyrochemical recovery of actinides from spent metallic nuclear fuel by electrochemical methods in molten LiCl-KCl. In the present work, the most important steps of this route were experimentally tested using U-Pu-Al alloy prepared by electrodeposition of U and Pu on solid aluminium plate electrodes. The investigated processes were vacuum distillation for removal of the salt adhered on the electrode, chlorination of the alloy by chlorine gas and sublimation of the AlCl3 formed. The processes parameters were set on the base of a previous thermochemical study and an experimental work using pure UAl3 alloy. The present experimental results indicated high efficiency of salt distillation and chlorination steps, while the sublimation step should be further optimised.

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

    Directory of Open Access Journals (Sweden)

    Walter Olaf

    2016-09-01

    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.

  3. Bidentate organophosphorus solvent extraction process for actinide recovery and partition

    Science.gov (United States)

    Schulz, Wallace W.

    1976-01-01

    A liquid-liquid extraction process for the recovery and partitioning of actinide values from acidic nuclear waste aqueous solutions, the actinide values including trivalent, tetravalent and hexavalent oxidation states is provided and includes the steps of contacting the aqueous solution with a bidentate organophosphorous extractant to extract essentially all of the actinide values into the organic phase. Thereafter the respective actinide fractions are selectively partitioned into separate aqueous solutions by contact with dilute nitric or nitric-hydrofluoric acid solutions. The hexavalent uranium is finally removed from the organic phase by contact with a dilute sodium carbonate solution.

  4. 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

  5. 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)

    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 38th 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

  6. Advanced Extraction Methods for Actinide/Lanthanide Separations

    Energy Technology Data Exchange (ETDEWEB)

    Scott, M.J.

    2005-12-01

    high level liquid wastes and a general actinide clean-up procedure. The selectivity of the standard extractant for tetravalent actinides, (N,N-diisobutylcarbamoylmethyl) octylphenylphosphineoxide (CMPO), was markedly improved by the attachment of three CMPO-like functions onto a triphenoxymethane platform, and a ligand that is both highly selective and effective for An(IV) ions was isolated. A 10 fold excess of ligand will remove virtually all of the 4+ actinides from the acidic layer without extracting appreciable quantities of An(III) and Ln(III) unlike simple CMPO ligands. Inspired by the success of the DIAMEX industrial process for extractions, three new tripodal chelates bearing three diglycolamide and thiodiglycolamide units precisely arranged on a triphenoxymethane platform have been synthesized for an highly efficient extraction of trivalent f-element cations from nitric acid media. A single equivalent of ligand will remove 80% of the Ln(III) ion from the acidic layer since the ligand is perfectly suited to accommodate the tricapped trigonal prismatic geometry preferred by the metal center. The ligand is perhaps the most efficient binder available for the heavier lanthanides and due to this unique attribute, the extraction event can be easily followed by 1H NMR spectroscopy confirming the formation of a TPP complex. The most lipophilic di-n-butyl tris-diglycolamide was found to be a significantly weaker extractant in comparison to the di-isopropyl analogs. The tris-thiodiglycolamide derivative proved to be an ineffective chelate for f-elements and demonstrated the importance of the etheric oxygens in the metal binding. The results presented herein clearly demonstrate a cooperative action of these three ligating groups within a single molecule, confirmed by composition and structure of the extracted complexes, and since actinides prefer to have high coordination numbers, the ligands should be particularly adept at binding with three arms. The use of such an

  7. Fundamental Thermodynamics of Actinide-Bearing Mineral Waste Forms - Final Report

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-03-01

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

  8. Fundamental Thermodynamics of Actinide-Bearing Mineral Waste Forms - Final Report

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Williamson, M.A. [Los Alamos National Lab., NM (US); Ebbinghaus, B.B.

    1998-06-01

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

  10. Evaluation and testing of sequestering agents for the removal of actinides from waste streams

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, D.C.; Romanovski, V.V.; Veeck, A.C. [Lawrence Livermore National Lab., CA (United States)] [and others

    1997-10-01

    The purpose of this project is to evaluate and test the complexing ability of a variety of promising new complexing agents synthesized by Professor Kenneth Raymond`s group at the University of California, Berkeley (ESP-CP TTP Number SF16C311). Some of these derivatives have already shown the potential for selectivity binding Pu(IV) in a wide range of solutions in the presence of other metals. Professor Raymond`s group uses molecular modeling to design and synthesize ligands based on modification of natural siderophores, or their analogs, for chelation of actinides. The ligands are then modified for use as liquid/liquid and solid/liquid extractants. The authors` group at the Glenn T. Seaborg Institute for Transactinium Science (ITS) at Lawrence Livermore National Laboratory determines the complex formation constants between the ligands and actinide ions, the capacity and time dependence for uptake on the resins, and the effect of other metal ions and pH.

  11. Transmutation of minor actinide using thorium fueled BWR core

    International Nuclear Information System (INIS)

    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 6th 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

  12. Research needs in metabolism and dosimetry of the actinides

    International Nuclear Information System (INIS)

    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;

  13. Chemistry of lower valent actinide halides

    Energy Technology Data Exchange (ETDEWEB)

    Lau, K.H.; Hildenbrand, D.L.

    1992-01-01

    This research effort was concerned almost entirely with the first two members of the actinide series, thorium and uranium, although the work was later extended to some aspects of the neptunium-fluorine system in a collaborative program with Los Alamos National Laboratory. Detailed information about the lighter actinides will be helpful in modeling the properties of the heavier actinide compounds, which will be much more difficult to study experimentally. In this program, thermochemical information was obtained from high temperature equilibrium measurements made by effusion-beam mass spectrometry and by effusion-pressure techniques. Data were derived primarily from second-law analysis so as to avoid potential errors in third-law calculations resulting from uncertainties in spectroscopic and molecular constants. This approach has the additional advantage of yielding reaction entropies that can be checked for consistency with various molecular constant assignments for the species involved. In the U-F, U-Cl, and U-Br systems, all of the gaseous species UX, UX{sub 2}, UX{sub 3}, UX{sub 4}, and UX{sub 5}, where X represents the halogen, were identified and characterized; the corresponding species ThX, ThX{sub 2}, ThX{sub 3}, and ThX{sub 4} were studied in the Th-F, Th-Cl, and Th-Br systems. A number of oxyhalide species in the systems U-0-F, U-0-Cl, Th-0-F, and Th-O-Cl were studied thermochemically. Additionally, the sublimation thermodynamics of NpF{sub 4}(s) and NpO{sub 2}F{sub 2}(s) were studied by mass spectrometry.

  14. Clays at the natural nuclear reactor at Bangombe, Gabon: migration of actinides

    International Nuclear Information System (INIS)

    Clay minerals were examined from the natural nuclear reactor at Bangombe. The clay mineralogy of the reactor facies is: illite, kaolinite and minor chlorite (FB formation); illite with chlorite and kaolinite in hydrothermal veins (argile de pile); illite and chlorite (reactor core); and (i) chlorite and kaolinite ± illite ± smectite or (ii) illite in the underlying FA formation. Illite crystallinity values are in general highest in rocks that experienced the highest temperatures during reactor operation. Chlorite chemistry varies with respect to position around the reactor: both di-tri and trioctahedral chlorites are present in hydrothermal veins within the argile de pile, dioctahedral chlorites are present in the FA formation within cm of the reactor core, trioctahedral chlorites are present within a meter of the reactor. Chemical data for the argile de pile and the FB formation suggest that formation of the former unit occurred as a result of thermal metamorphism of the FB pelites, as opposed to large-scale dissolution of the sandstones of the FA formation. Autoradiography is used to study the sorptive characteristics of the clays for actinides. The results show that actinide sorption varies in the order: chlorite > illite ≅ kaolinite. (orig.)

  15. Actinide management with commercial fast reactors

    International Nuclear Information System (INIS)

    The capability of plutonium-breeding and minor-actinide (MA) transmutation in the Japanese commercial sodium-cooled fast reactor offers one of practical solutions for obtaining sustainable energy resources as well as reducing radioactive toxicity and inventory. The reference core design meets the requirement of flexible breeding ratio from 1.03 to 1.2. The MA transmutation amount has been evaluated as 50-100 kg/GWey if the MA content in fresh fuel is 3-5 wt%, where about 30-40% of initial MA can be transmuted in the discharged fuel

  16. Actinide management with commercial fast reactors

    Science.gov (United States)

    Ohki, Shigeo

    2015-12-01

    The capability of plutonium-breeding and minor-actinide (MA) transmutation in the Japanese commercial sodium-cooled fast reactor offers one of practical solutions for obtaining sustainable energy resources as well as reducing radioactive toxicity and inventory. The reference core design meets the requirement of flexible breeding ratio from 1.03 to 1.2. The MA transmutation amount has been evaluated as 50-100 kg/GWey if the MA content in fresh fuel is 3-5 wt%, where about 30-40% of initial MA can be transmuted in the discharged fuel.

  17. Compilation of actinide neutron nuclear data

    International Nuclear Information System (INIS)

    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.)

  18. 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.

  19. Supercritical fluid extraction studies on actinides

    International Nuclear Information System (INIS)

    Uranyl nitrate and plutonium in its Pu (III) as well Pu (IV) form loaded onto a tissue paper was extracted completed from paper, glass, stainless steel as well as teflon matrices using modified SC-CO2. A further investigation on recovery of actinides independent of their drying period is expected to culminate into developing an universal procedure to handle Pu bearing waste for its recovery irrespective of its drying history and oxidation states. Such endeavors ultimately lead to the potential utility of the SFE technology for efficient nuclear waste management

  20. Recent progress in actinide borate chemistry

    OpenAIRE

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

    2011-01-01

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

  1. Actinide management with commercial fast reactors

    Energy Technology Data Exchange (ETDEWEB)

    Ohki, Shigeo [Japan Atomic Energy Agency, 4002, Narita-cho, O-arai-machi, Higashi-Ibaraki-gun, Ibaraki 311-1393 (Japan)

    2015-12-31

    The capability of plutonium-breeding and minor-actinide (MA) transmutation in the Japanese commercial sodium-cooled fast reactor offers one of practical solutions for obtaining sustainable energy resources as well as reducing radioactive toxicity and inventory. The reference core design meets the requirement of flexible breeding ratio from 1.03 to 1.2. The MA transmutation amount has been evaluated as 50-100 kg/GW{sub e}y if the MA content in fresh fuel is 3-5 wt%, where about 30-40% of initial MA can be transmuted in the discharged fuel.

  2. 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 t...... 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...

  3. 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)

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

    International Nuclear Information System (INIS)

    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

  5. Fusion-Fission Burner for Transuranic Actinides

    Science.gov (United States)

    Choi, Chan

    2013-10-01

    The 14-MeV DT fusion neutron spectrum from mirror confinement fusion can provide a unique capability to transmute the transuranic isotopes from light water reactors (LWR). The transuranic (TRU) actinides, high-level radioactive wastes, from spent LWR fuel pose serious worldwide problem with long-term decay heat and radiotoxicity. However, ``transmuted'' TRU actinides can not only reduce the inventory of the TRU in the spent fuel repository but also generate additional energy. Typical commercial LWR fuel assemblies for BWR (boiling water reactor) and PWR (pressurized water reactor) measure its assembly lengths with 4.470 m and 4.059 m, respectively, while its corresponding fuel rod lengths are 4.064 m and 3.851 m. Mirror-based fusion reactor has inherently simple geometry for transmutation blanket with steady-state reactor operation. Recent development of gas-dynamic mirror configuration has additional attractive feature with reduced size in central plasma chamber, thus providing a unique capability for incorporating the spent fuel assemblies into transmutation blanket designs. The system parameters for the gas-dynamic mirror-based hybrid burner will be discussed.

  6. Electronic structure of the actinide dioxides

    International Nuclear Information System (INIS)

    The electronic properties of the fluorite structured actinide dioxides have been investigated using the linear muffin tin orbital method in the atomic sphere approximation. CaF2 with the same structure was also studied because of the relative simplicity of its electronic structure and the greater amount of experimental data available. Band structures were calculated both non self consistently and self consistently. In the non self consistent calculations the effect of changing the approximation to the exchange-correlation potential and the starting atomic configurations was examined. Using the concepts of canonical bands the effects of hybridization were investigated. In particular the 5f electrons included in the band picture were found to mix more strongly into the valence band than indicated by experiment. On this basis the 5f electrons were not included in self consistent calculations which in the density functional formalism are capable of yielding ground state properties. Because of the non participation of the f electrons in the bonding UO2 only was considered as representative of the actinide dioxides. For comparison CaF2 was also examined. Using Pettifor's pressure formula to determine the equilibrium condition the lattice constants were calculated to be 0.5% and 5% respectively below the experimental values. (author)

  7. New unsymmetrical digycolamide ligands for trivalent actinide separation

    Energy Technology Data Exchange (ETDEWEB)

    Ravi, Jammu; Venkatesan, K.A.; Antony, M.P.; Srinivasan, T.G.; Rao, P.R. Vasudeva [Indira Gandhi Centre for Atomic Research, Kalpakkam (India). Fuel Chemistry Div.

    2014-10-01

    New unsymmetrical diglycolamides (UDGAs), N,N-di-butyl-N',N'-di-dodecyl-3-oxapentane-1,5-diamide (C{sub 12}-C{sub 4}), N,N-di-dodecyl-N',N'-di-hexyl-3-oxapentane-1,5-diamide (C{sub 12}-C{sub 6}), N,N-di-decyl-N',N'-di-dodecyl-3-oxapentane-1,5-diamide (C{sub 12}-C{sub 10}) have been synthesized, and evaluated for the separation of americium(III) and europium(III) from nitric acid medium. The extraction behavior of Am(III), Eu(III), and Sr(II) in a solution of these UDGAs in n-dodecane was studied as a function of concentration of nitric acid in the aqueous phase. The distribution ratio of Am(III) and Eu(III) increased with increase in the concentration of nitric acid. The third phase formation behavior of nitric acid and neodymium(III) in 0.1 M UDGA/n-dodecane was studied. The third phase formation was not observed in all these UDGAs in n-dodecane (0.1 M), when the concentration of Nd(III) was ∝ 500 mM in 3-4M nitric acid. The stoichiometry of Am(III)-UDGA was determined from the slope analysis of the extraction data, which indicated the formation of 1:3 complex in all cases. Our studies revealed that the UDGA ligands with dodecyl group attached to one amidic nitrogen atom is inevitable for preventing third phase formation and the alkyl group at the other amidic nitrogen can be varied from butyl to decyl group for obtaining efficient extraction of trivalent actinides from high-level nuclear waste. (orig.)

  8. Gas core reactors for actinide transmutation. [uranium hexafluoride

    Science.gov (United States)

    Clement, J. D.; Rust, J. H.; Wan, P. T.; Chow, S.

    1979-01-01

    The preliminary design of a uranium hexafluoride actinide transmutation reactor to convert long-lived actinide wastes to shorter-lived fission product wastes was analyzed. It is shown that externally moderated gas core reactors are ideal radiators. They provide an abundant supply of thermal neutrons and are insensitive to composition changes in the blanket. For the present reactor, an initial load of 6 metric tons of actinides is loaded. This is equivalent to the quantity produced by 300 LWR-years of operation. At the beginning, the core produces 2000 MWt while the blanket generates only 239 MWt. After four years of irradiation, the actinide mass is reduced to 3.9 metric tonnes. During this time, the blanket is becoming more fissile and its power rapidly approaches 1600 MWt. At the end of four years, continuous refueling of actinides is carried out and the actinide mass is held constant. Equilibrium is essentially achieved at the end of eight years. At equilibrium, the core is producing 1400 MWt and the blanket 1600 MWt. At this power level, the actinide destruction rate is equal to the production rate from 32 LWRs.

  9. Separation of actinides from spent nuclear fuel: A review.

    Science.gov (United States)

    Veliscek-Carolan, Jessica

    2016-11-15

    This review summarises the methods currently available to extract radioactive actinide elements from solutions of spent nuclear fuel. This separation of actinides reduces the hazards associated with spent nuclear fuel, such as its radiotoxicity, volume and the amount of time required for its' radioactivity to return to naturally occurring levels. Separation of actinides from environmental water systems is also briefly discussed. The actinide elements typically found in spent nuclear fuel include uranium, plutonium and the minor actinides (americium, neptunium and curium). Separation methods for uranium and plutonium are reasonably well established. On the other hand separation of the minor actinides from lanthanide fission products also present in spent nuclear fuel is an ongoing challenge and an area of active research. Several separation methods for selective removal of these actinides from spent nuclear fuel will be described. These separation methods include solvent extraction, which is the most commonly used method for radiochemical separations, as well as the less developed but promising use of adsorption and ion-exchange materials.

  10. Separation of actinides from spent nuclear fuel: A review.

    Science.gov (United States)

    Veliscek-Carolan, Jessica

    2016-11-15

    This review summarises the methods currently available to extract radioactive actinide elements from solutions of spent nuclear fuel. This separation of actinides reduces the hazards associated with spent nuclear fuel, such as its radiotoxicity, volume and the amount of time required for its' radioactivity to return to naturally occurring levels. Separation of actinides from environmental water systems is also briefly discussed. The actinide elements typically found in spent nuclear fuel include uranium, plutonium and the minor actinides (americium, neptunium and curium). Separation methods for uranium and plutonium are reasonably well established. On the other hand separation of the minor actinides from lanthanide fission products also present in spent nuclear fuel is an ongoing challenge and an area of active research. Several separation methods for selective removal of these actinides from spent nuclear fuel will be described. These separation methods include solvent extraction, which is the most commonly used method for radiochemical separations, as well as the less developed but promising use of adsorption and ion-exchange materials. PMID:27427893

  11. Scenarios for the transmutation of actinides in CANDU reactors

    Energy Technology Data Exchange (ETDEWEB)

    Hyland, Bronwyn, E-mail: hylandb@aecl.ca [Atomic Energy of Canada Limited, Chalk River Laboratories, Chalk River, Ontario, K0J 1J0 (Canada); Gihm, Brian, E-mail: gihmb@aecl.ca [Atomic Energy of Canada Limited, 2251 Speakman Drive, Mississauga, Ontario, L5K 1B2 (Canada)

    2011-12-15

    With world stockpiles of used nuclear fuel increasing, the need to address the long-term utilization of this resource is being studied. Many of the transuranic (TRU) actinides in nuclear spent fuel produce decay heat for long durations, resulting in significant nuclear waste management challenges. These actinides can be transmuted to shorter-lived isotopes to reduce the decay heat period or consumed as fuel in a CANDU(R) reactor. Many of the design features of the CANDU reactor make it uniquely adaptable to actinide transmutation. The small, simple fuel bundle simplifies the fabrication and handling of active fuels. Online refuelling allows precise management of core reactivity and separate insertion of the actinides and fuel bundles into the core. The high neutron economy of the CANDU reactor results in high TRU destruction to fissile-loading ratio. This paper provides a summary of actinide transmutation schemes that have been studied in CANDU reactors at AECL, including the works performed in the past. The schemes studied include homogeneous scenarios in which actinides are uniformly distributed in all fuel bundles in the reactor, as well as heterogeneous scenarios in which dedicated channels in the reactor are loaded with actinide targets and the rest of the reactor is loaded with fuel. The transmutation schemes that are presented reflect several different partitioning schemes. Separation of americium, often with curium, from the other actinides enables targeted destruction of americium, which is a main contributor to the decay heat 100-1000 years after discharge from the reactor. Another scheme is group-extracted transuranic elements, in which all of the transuranic elements, plutonium (Pu), neptunium (Np), americium (Am), and curium (Cm) are extracted together and then transmuted. This paper also addresses ways of utilizing the recycled uranium, another stream from the separation of spent nuclear fuel, in order to drive the transmutation of other actinides.

  12. An emergency bioassay method for actinides in urine.

    Science.gov (United States)

    Dai, Xiongxin; Kramer-Tremblay, Sheila

    2011-08-01

    A rapid bioassay method has been developed for the sequential measurements of actinides in human urine samples. The method involves actinide separation from a urine matrix by co-precipitation with hydrous titanium oxide (HTiO), followed by anion exchange and extraction chromatography column purification, and final counting by alpha spectrometry after cerium fluoride micro-precipitation. The minimal detectable activities for the method were determined to be 20 mBq L(-1) or less for plutonium, uranium, americium and curium isotopes, with an 8-h sample turn-around time. Spike tests showed that this method would meet the requirements for actinide bioassay following a radiation emergency. PMID:21709501

  13. Distribution of actinides in SFR1; Aktinidfoerdelning i SFR1

    Energy Technology Data Exchange (ETDEWEB)

    Ingemansson, Tor [ALARA Engineering, Skultuna (Sweden)

    2000-02-01

    The amount of actinides in the Swedish repository for intermediate level radioactive wastes has been estimated. The sources for the actinides are mainly the purification filters of the reactors and the used fuel pools. Defect fuel elements are the originating source of the actinides. It is estimated that the 12 Swedish reactors, in total, have had 2.2 kg of fuel dissolved in their systems since start-up. About 880 g of this amount has been brought to the intermediate-level repository.

  14. Report of the panel on practical problems in actinide biology

    International Nuclear Information System (INIS)

    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

  15. Status report on actinide and fission product transmutation studies

    International Nuclear Information System (INIS)

    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

  16. 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)

  17. Actinide interactions at microbial interfaces: an interdisciplinary challenge

    International Nuclear Information System (INIS)

    An overview on the current state of knowledge of microbial actinide interaction processes is presented. Several detailed examples of the interaction of aerobic soil bacteria (Pseudomonas, Bacillus and Deinococcus strains) with uranium and plutonium are discussed. Details of the nature of the bacterial functional groups involved in the interfacial actinide interaction process are reported. Based on time-resolved laser-induced fluorescence spectroscopy (TRLFS) and synchrotron X-ray absorption spectroscopy (XANES and EXAFS) studies, molecular-level mechanistic details of the different interaction processes are discussed. Areas of this emerging field in actinide research are outlined where additional information and integrated interdisciplinary research is required

  18. Separating the Minor Actinides Through Advances in Selective Coordination Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Lumetta, Gregg J.; Braley, Jenifer C.; Sinkov, Sergey I.; Carter, Jennifer C.

    2012-08-22

    This report describes work conducted at the Pacific Northwest National Laboratory (PNNL) in Fiscal Year (FY) 2012 under the auspices of the Sigma Team for Minor Actinide Separation, funded by the U.S. Department of Energy Office of Nuclear Energy. Researchers at PNNL and Argonne National Laboratory (ANL) are investigating a simplified solvent extraction system for providing a single-step process to separate the minor actinide elements from acidic high-level liquid waste (HLW), including separating the minor actinides from the lanthanide fission products.

  19. The effects of actinide separation on the radiological consequences of geologic disposal of high-level waste

    International Nuclear Information System (INIS)

    It has often been suggested that the potential hazard to man from the disposal of high-level radioactive waste could be reduced by removing a substantial fraction of the actinide elements. In this report the effects of actinide separation on the radiological consequences of one of the disposal options currently under consideration, that of burial in deep geologic formations, are examined. The results show that the potential radiological impact of geologic disposal of high-level waste arises from both long-lived fission products and actinides (and their daughter radionuclides). Neither class of radionuclides is of overriding importance and actinide separation would therefore reduce the radiological impact to only a limited extent and over limited periods. There might be a case for attempting to reduce doses from 237Np. To achieve this it appears to be necessary to separate both neptunium and its precursor element americium. However, there are major uncertainties in the data needed to predict doses from 237Np; further research is required to resolve these uncertainties. In addition, consideration should be given to alternative methods of reducing the radiological impact of geologic disposal. The conclusions of this assessment differ considerably from those of similar studies based on the concept of toxicity indices. Use of these indices can lead to incorrect allocation of research and development effort. (author)

  20. Solidification of simulated actinides by natural zircon

    Institute of Scientific and Technical Information of China (English)

    YANG Jian-Wen; LUO Shang-Geng

    2004-01-01

    Natural zircon was used as precursor material to produce a zircon waste form bearing 20wt% simulated actinides (Nd2O3 and UO2) through a solid state reaction by a typical synroc fabrication process. The fabricated zircon waste form has relatively good physical properties (density 5.09g/cm3, open porosity 4.0%, Vickers hardness 715kg/mm2). The XRD, SEM/EDS and TEM/EDS analyses indicate that there are zircon phases containing waste elements formed through the reaction. The chemical durability and radiation stability are determined by the MCC-1method and heavy ion irradiation; the results show that the zircon waste form is highly leach resistance and relatively stable under irradiation (amorphous dose 0.7dpa). From this study, the method of using a natural mineral to solidify radioactive waste has proven to be feasible.

  1. Actinide elements in aquatic and terrestrial environments

    International Nuclear Information System (INIS)

    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

  2. Gamma spectroscopy of neutron rich actinide nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Birkenbach, Benedikt; Geibel, Kerstin; Vogt, Andreas; Hess, Herbert; Reiter, Peter; Steinbach, Tim; Schneiders, David [Koeln Univ. (Germany). IKP; Collaboration: AGATA-Collaboration

    2013-07-01

    Excited states in neutron-rich actinide Th and U nuclei were investigated after multi nucleon transfer reactions employing the AGATA demonstrator and PRISMA setup at LNL (INFN, Italy). A primary {sup 136}Xe beam of 1 GeV hitting a {sup 238}U target was used to produce the nuclei of interest. Beam-like reaction products of Xe- and Ba isotopes after neutron transfer were selected by the PRISMA spectrometer. The recoil like particles were registered by a MCP detector inside the scattering chamber. Coincident γ-rays from excited states in beam and target like particles were measured with the position sensitive AGATA HPGe detectors. Improved Doppler correction and quality of the γ-spectra is based on the novel γ-ray tracking technique which was successfully exploited. First results on the collective properties of various Th and U isotopes are discussed.

  3. 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.

  4. 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.

  5. Pyrometallurgical processes for recovery of actinide elements

    International Nuclear Information System (INIS)

    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

  6. An atomic beam source for actinide elements: concept and realization

    International Nuclear Information System (INIS)

    For ultratrace analysis of actinide elements and studies of their atomic properties with resonance ionization mass spectroscopy (RIMS), efficient and stable sources of actinide atomic beams are required. The thermodynamics and kinetics of the evaporation of actinide elements and oxides from a variety of metals were considered, including diffusion, desorption, and associative desorption. On this basis various sandwich-type filaments were studied. The most promising system was found to consist of tantalum as the backing material, an electrolytically deposited actinide hydroxide as the source of the element, and a titanium covering layer for its reduction to the metal. Such sandwich sources were experimentally proven to be well suited for the production of atomic beams of plutonium, curium, berkelium and californium at relatively low operating temperatures and with high and reproducible yields. (orig.)

  7. Distribution of actinide elements in sediments: leaching studies

    International Nuclear Information System (INIS)

    Previous investigations have shown that Fe and Mn oxides and organic matter can significantly influence the behavior of Pu and other actinides in the environment. A sequential leaching procedure has been developed in order to investigate the solid phase distribution of the actinides in riverine and marine sediments. Seven different sedimentary fractions are defined by this leaching experiment: an exchangeable metals fraction, an organic fraction, a carbonate fraction, a Mn oxide fraction, an amorphous Fe fraction, a crystalline Fe oxide fraction and a lattice-held or residual fraction. There is also the option of including a metal sufide fraction. A preliminary experiment, analyzing only the metals and not the actinide elements, indicates that this leaching procedure (with some modifications) is a viable procedure. The subsequent data should result in information concerning the geochemical history and behavior of these actinide elements in the environment

  8. Element Partitioning in Glass-Ceramic Designed for Actinides Immobilization

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>Glass-ceramics were designed for immobilization of actinides. In order to immobilizing more wastes in the matrix and to develop the optimum formulation for the glass-ceramic, it is necessary to study the

  9. Advanced techniques for actinide spectroscopy (ATAS 2012). Abstract book

    International Nuclear Information System (INIS)

    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.

  10. 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.

  11. Separation of Minor Actinides from Lanthanides by Dithiophosphinic Acid Extractants

    Energy Technology Data Exchange (ETDEWEB)

    D. R. Peterman; M. R. Greenhalgh; R. D. Tillotson; J. R. Klaehn; M. K. Harrup; T. A. Luther; J. D. Law; L. M. Daniels

    2008-09-01

    The selective extraction of the minor actinides (Am(III) and Cm(III)) from the lanthanides is an important part of advanced reprocessing of spent nuclear fuel. This separation would allow the Am/Cm to be fabricated into targets and recycled to a reactor and the lanthanides to be dispositioned. This separation is difficult to accomplish due to the similarities in the chemical properties of the trivalent actinides and lanthanides. Research efforts at the Idaho National Laboratory have identified an innovative synthetic pathway yielding new regiospecific dithiophosphinic acid (DPAH) extractants. The synthesis provides DPAH derivatives that can address the issues concerning minor actinide separation and extractant stability. For this work, two new symmetric DPAH extractants have been prepared. The use of these extractants for the separation of minor actinides from lanthanides will be discussed.

  12. Electronic structure and properties of rare earth and actinide intermetallics

    International Nuclear Information System (INIS)

    There are 188 contributions, experimental and theoretical, a few on rare earth and actinide elements but mostly on rare earth and actinide intermetallic compounds and alloys. The properties dealt with include 1) crystal structure, 2) magnetic properties and magnetic structure, 3) magnetic phase transformations and valence fluctuations, 4) electrical properties and superconductivity and their temperature, pressure and magnetic field dependence. A few papers deal with crystal growth and novel measuring methods. (G.Q.)

  13. The effect of corrosion product colloids on actinide transport

    International Nuclear Information System (INIS)

    The near field of the proposed UK repository for ILW/LLW will contain containers of conditioned waste in contact with a cementious backfill. It will contain significant quantities of iron and steel, Magnox and Zircaloy. Colloids deriving from their corrosion products may possess significant sorption capacity for radioelements. If the colloids are mobile in the groundwater flow, they could act as a significant vector for activity transport into the far field. The desorption of plutonium and americium from colloidal corrosion products of iron and zirconium has been studied under chemical conditions representing the transition from the near field to the far field. Desorption Rd values of ≥ 5 x 106 ml g-1 were measured for both actinides on these oxides and hydroxides when actinide sorption took place under the near-field conditions and desorption took place under the far-field conditions. Desorption of the actinides occurred slowly from the colloids under far-field conditions when the colloids had low loadings of actinide and more quickly at high loadings of actinide. Desorbed actinide was lost to the walls of the experimental vessel. (author)

  14. Research on the actinide chemistry in Nuclear Fuel Cycle

    International Nuclear Information System (INIS)

    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.

  15. Analysis of the Gas Core Actinide Transmutation Reactor (GCATR)

    Science.gov (United States)

    Clement, J. D.; Rust, J. H.

    1977-01-01

    Design power plant studies were carried out for two applications of the plasma core reactor: (1) As a breeder reactor, (2) As a reactor able to transmute actinides effectively. In addition to the above applications the reactor produced electrical power with a high efficiency. A reactor subsystem was designed for each of the two applications. For the breeder reactor, neutronics calculations were carried out for a U-233 plasma core with a molten salt breeding blanket. A reactor was designed with a low critical mass (less than a few hundred kilograms U-233) and a breeding ratio of 1.01. The plasma core actinide transmutation reactor was designed to transmute the nuclear waste from conventional LWR's. The spent fuel is reprocessed during which 100% of Np, Am, Cm, and higher actinides are separated from the other components. These actinides are then manufactured as oxides into zirconium clad fuel rods and charged as fuel assemblies in the reflector region of the plasma core actinide transmutation reactor. In the equilibrium cycle, about 7% of the actinides are directly fissioned away, while about 31% are removed by reprocessing.

  16. Comparative studies of actinide and sub-actinide fission cross section calculation from MCNP6 and TALYS

    Energy Technology Data Exchange (ETDEWEB)

    Perkasa, Y. S. [Department of Physics, Sunan Gunung Djati State Islamic University Bandung, Jl. A.H Nasution No. 105 Cibiru, Bandung (Indonesia); Waris, A., E-mail: awaris@fi.itb.ac.id; Kurniadi, R., E-mail: awaris@fi.itb.ac.id; Su' ud, Z., E-mail: awaris@fi.itb.ac.id [Nuclear Physics and Biophysics Research Division, Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesa No. 10 Bandung 40132 (Indonesia)

    2014-09-30

    Comparative studies of actinide and sub-actinide fission cross section calculation from MCNP6 and TALYS have been conducted. In this work, fission cross section resulted from MCNP6 prediction will be compared with result from TALYS calculation. MCNP6 with its event generator CEM03.03 and LAQGSM03.03 have been validated and verified for several intermediate and heavy nuclides fission reaction data and also has a good agreement with experimental data for fission reaction that induced by photons, pions, and nucleons at energy from several ten of MeV to about 1 TeV. The calculation that induced within TALYS will be focused mainly to several hundred MeV for actinide and sub-actinide nuclides and will be compared with MCNP6 code and several experimental data from other evaluator.

  17. Coordination chemistry of several radius-sensitive complexones and applications to lanthanide-actinide separations

    International Nuclear Information System (INIS)

    The relationships between the lanthanide complex formation equilibria and the lanthanide-actinide separation application of three radius sensitive ligands have been studied. The consecutive stepwise formation constants of the 1:1, 2:1, and 3:1 chelate species formed by the interaction of DHDMB and the tripositive lanthanides and yttrium were determined potentiometrically at 0.1 M ionic strength and 250C. Results indicate that three different coordination modes, one tridentate and two bidentate are in evidence. Tracer level 241Am - 155Eu cation-exchange experiments utilizing DHDMB eluents indicate that this dihydroxycarboxylate does not form a sufficiently strong americium complex to elute that actinide ahead of europium. The overall stability of the americium 3:1 complex appears intermediate between samarium and europium. Cation-exchange elutions of 241Am, 155Eu, and 160Tb mixtures with EEDTA solutions prove that the EEDTA ligand is capable of eluting americium ahead of all of the tripositive lanthanide cations. The minimum separation occurs with terbium, where the Am-Tb separation factor is 1.71. 1,5-diaminopentane-N,N,N',N'-tetraacetic acid (PMDTA) was synthesized using cation exchange. A mathematical method was developed for the formation constants of the protonated and unprotonated lanthanide-PMDTA complexes from potentiometry. Cation-exchange elutions of tracer quantities of Am, Eu, and Tb revealed that terbium is eluted ahead of both americium and europium

  18. Mass spectrometric studies of the complexing behaviour of actinide ions in solution

    International Nuclear Information System (INIS)

    As the long-term radiotoxicity of spent nuclear fuel is governed by Plutonium and the Minor Actinides, these elements are focussed on for investigations in the framework of safety assessment for nuclear waste repositories. To shed more light on the selectivity of the partitioning ligands BTP and BTBP towards the extraction of trivalent actinides, the complexes these ligands form with lanthanides in octanolic solution were characterized. The differences in the extraction efficiencies among the different lanthanides were traced back to the varying preferential formation of Ln(BTP)3 complexes, depending on the ionic radius of the lanthanides. Additionally it was shown that depending on the sterical demand of BTBP ligands nitrate anions coordinate in the first coordination shell of Eu(BTBP)2-complexes. As the behavior of Plutonium under geochemical conditions is of particular interest for the safety assessment of potential nuclear waste repositories, the second part of the thesis focuses on the hydrolysis and colloid formation behavior of aqueous Plutonium solutions. The solution species of Zirconium(IV) as analogue for Plutonium(IV) as well as of Uranium(VI) and Plutonium(VI) were characterized and quantified by means of electrospray ionization mass spectrometry. Moreover the colloid-induced reduction of Pu(V) to Pu(IV) and the subsequent formation of colloidal species was investigated.

  19. Synthesis and Structural Examination of Complexes of Am(IV) and Other Tetravalent Actinides with Lacunary Heteropolyanion α2-P2W17O6110-

    International Nuclear Information System (INIS)

    This study concerns the formation of complexes with actinides at oxidation state +IV, from Th to Am, through a lacunary heteropolyanion ligand P2W17O6110-. The preparation of original single crystals of complexes with 1:2 stoichiometry provided structural data through single-crystal X-ray diffraction for the entire An(IV) series, An(IV) atoms in these complexes have a coordination number of 8, and their coordination polyhedron is a distorted square anti-prism. The data were used to compute a mean (An-O) interatomic distance for each actinide. When the interatomic distance is plotted versus the inverse ionic radius of these tetravalent actinides, it appears that the simple electrostatic model is not suitable for Am(IV) and Pu(IV), although this trend must be confirmed by further investigation with other examples from the An(IV) series. (authors)

  20. Interaction of actinides with amino acids: from peptides to proteins

    International Nuclear Information System (INIS)

    Structural information on complexes of actinides with molecules of biological interest is required to better understand the mechanisms of actinides transport in living organisms, and can contribute to develop new decorporation treatments. Our study is about Th(IV), Np(IV), Pu(IV) and uranyl(VI) cations, which have a high affinity for some protein domains, and Fe(III), which is the natural cation of these biological systems. In this work, chelation of actinides has been brought to light with UV-visible-Near Infra Red spectroscopy, NMR, EPR, and ultrafiltration. Determination of the structure of the complexation site has been undertaken with Exafs measurements, and of the tertiary structure of the protein with SANS measurements. The first approach was to describe the interaction modes between actinides and essential chemical functions of proteins. Thus, the Ac-AspAspProAspAsp-NH2 peptide was studied as a possible chelate of actinides. Polynuclear species with μ-oxo or μ-hydroxo bridges were identified. The iron complex is binuclear, and the actinide ones have a higher nuclearity. The second approach was to study a real case of complexation of actinide with a protein: transferrin. Results show that around physiological ph a mononuclear complex is formed with Np(IV) and Pu(IV), while transferrin does not complex Th(IV) in the same conditions. Characteristic distances of M-transferrin complexes (M = Fe, Np, Pu) were determined. Moreover, the protein seems to be in its close conformation with Pu(IV), and in its open form with Np(IV) and UO22+. (author)

  1. Actinide production in 136Xe bombardments of 249Cf

    International Nuclear Information System (INIS)

    The production cross sections for the actinide products from 136Xe bombardments of 249Cf at energies 1.02, 1.09, and 1.16 times the Coulomb barrier were determined. Fractions of the individual actinide elements were chemically separated from recoil catcher foils. The production cross sections of the actinide products were determined by measuring the radiations emitted from the nuclides within the chemical fractions. The chemical separation techniques used in this work are described in detail, and a description of the data analysis procedure is included. The actinide production cross section distributions from these 136Xe + 249Cf bombardments are compared with the production cross section distributions from other heavy ion bombardments of actinide targets, with emphasis on the comparison with the 136Xe + 248Cm reaction. A technique for modeling the final actinide cross section distributions has been developed and is presented. In this model, the initial (before deexcitation) cross section distribution with respect to the separation energy of a dinuclear complex and with respect to the Z of the target-like fragment is given by an empirical procedure. It is then assumed that the N/Z equilibration in the dinuclear complex occurs by the transfer of neutrons between the two participants in the dinuclear complex. The neutrons and the excitation energy are statistically distributed between the two fragments using a simple Fermi gas level density formalism. The resulting target-like fragment initial cross section distribution with respect to Z, N, and excitation energy is then allowed to deexcite by emission of neutrons in competition with fission. The result is a final cross section distribution with respect to Z and N for the actinide products. 68 refs., 33 figs., 6 tabs

  2. Actinides in irradiated graphite of RBMK-1500 reactor

    International Nuclear Information System (INIS)

    Highlights: • Activation of actinides in the graphite of the RBMK-1500 reactor was analyzed. • Numerical modeling using SCALE 6.1 and MCNPX was used for actinide calculation. • Measurements of the irradiated graphite sample were used for model validation. • Results are important for further decommissioning process of the RBMK type reactors. - Abstract: The activation of graphite in the nuclear power plants is the problem of high importance related with later graphite reprocessing or disposal. The activation of actinide impurities in graphite due to their toxicity determines a particular long term risk to waste management. In this work the activation of actinides in the graphite constructions of the RBMK-1500 reactor is determined by nuclear spectrometry measurements of the irradiated graphite sample from the Ignalina NPP Unit I and by means of numerical modeling using two independent codes SCALE 6.1 (using TRITON-VI sequence) and MCNPX (v2.7 with CINDER). Both models take into account the 3D RBMK-1500 reactor core fragment with explicit graphite construction including a stack and a sleeve but with a different simplification level concerning surrounding graphite and construction of control roads. The verification of the model has been performed by comparing calculated and measured isotope ratios of actinides. Also good prediction capabilities of the actinide activation in the irradiated graphite have been found for both calculation approaches. The initial U impurity concentration in the graphite model has been adjusted taking into account the experimental results. The specific activities of actinides in the irradiated RBMK-1500 graphite constructions have been obtained and differences between numerical simulation results, different structural parts (sleeve and stack) as well as comparison with previous results (Ancius et al., 2005) have been discussed. The obtained results are important for further decommissioning process of the Ignalina NPP and other RBMK

  3. Actinides in irradiated graphite of RBMK-1500 reactor

    Energy Technology Data Exchange (ETDEWEB)

    Plukienė, R., E-mail: rita@ar.fi.lt; Plukis, A.; Barkauskas, V.; Gudelis, A.; Gvozdaitė, R.; Duškesas, G.; Remeikis, V.

    2014-10-01

    Highlights: • Activation of actinides in the graphite of the RBMK-1500 reactor was analyzed. • Numerical modeling using SCALE 6.1 and MCNPX was used for actinide calculation. • Measurements of the irradiated graphite sample were used for model validation. • Results are important for further decommissioning process of the RBMK type reactors. - Abstract: The activation of graphite in the nuclear power plants is the problem of high importance related with later graphite reprocessing or disposal. The activation of actinide impurities in graphite due to their toxicity determines a particular long term risk to waste management. In this work the activation of actinides in the graphite constructions of the RBMK-1500 reactor is determined by nuclear spectrometry measurements of the irradiated graphite sample from the Ignalina NPP Unit I and by means of numerical modeling using two independent codes SCALE 6.1 (using TRITON-VI sequence) and MCNPX (v2.7 with CINDER). Both models take into account the 3D RBMK-1500 reactor core fragment with explicit graphite construction including a stack and a sleeve but with a different simplification level concerning surrounding graphite and construction of control roads. The verification of the model has been performed by comparing calculated and measured isotope ratios of actinides. Also good prediction capabilities of the actinide activation in the irradiated graphite have been found for both calculation approaches. The initial U impurity concentration in the graphite model has been adjusted taking into account the experimental results. The specific activities of actinides in the irradiated RBMK-1500 graphite constructions have been obtained and differences between numerical simulation results, different structural parts (sleeve and stack) as well as comparison with previous results (Ancius et al., 2005) have been discussed. The obtained results are important for further decommissioning process of the Ignalina NPP and other RBMK

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

    Energy Technology Data Exchange (ETDEWEB)

    Stipp, S.L.S.; Christensen, J.T.; Waight, T.E. [Geological Inst., Univ. of Copenhagen (Denmark); Lakshtanov, L.Z. [Geological Inst., Univ. of Copenhagen (Denmark); Inst. of Experimental Mineralogy, Russian Academy of Science, Chernogolovka (Russian Federation); Baker, J.A. [School of Earth Sciences, Victoria Univ. of Wellington (New Zealand)

    2006-07-01

    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{sup -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{sup -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{sup 3+} and Cm{sup 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

  5. Studies on Neutron, Photon (Bremsstrahlung and Proton Induced Fission of Actinides and Pre-Actinides

    Directory of Open Access Journals (Sweden)

    H. Naik

    2015-08-01

    Full Text Available We present the yields of various fission products determined in the reactor neutron, 3.7-18.1 MeV quasi-mono energetic neutron, 8-80 MeV bremsstrahlung and 20-45 MeV proton induced fission of 232Th and 238U using radiochemical and off-line beta or gamma ray counting. The yields of the fission products in the bremsstrahlung induced fission natPb and 209Bi with 50- 70 MeV and 2.5 GeV based on off-line gamma ray spectrometric technique were also presented. From the yields of fission products, the mass chains yields were obtained using charge distribution correction. From the mass yield distribution, the peak-to-valley (P/V ratio was obtained. The role of excitation energy on the peak-to-valley ratio and fine structure such as effect of shell closure proximity and even-odd effect of mass yield distribution were examined. The higher yields of the fission products around A=133-134, 138-140 and 143-144 and their complementary products explained from the nuclear structure effect and role of standard I and II mode of asymmetric fission. In the neutron, photon (bremsstrahlung and proton induced fission, the asymmetric mass distribution for actinides (Th, U and symmetric distribution for pre-actinides (Pb, Bi were explained from different type of potential fission barrier

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

    CERN Document Server

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

    1999-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, Boerje [Condensed Matter Theory Group, Department of Physics, Uppsala University, Box 530, S-751 21 Uppsala (Sweden); Applied Materials Physics, Department of Materials Science and Engineering, Royal Institute of Technology, Brinellvaegen 23, SE-100 44 Stockholm (Sweden)], E-mail: borje.johansson@fysik.uu.se; Li, Sa [Applied Materials Physics, Department of Materials Science and Engineering, Royal Institute of Technology, Brinellvaegen 23, SE-100 44 Stockholm (Sweden); Department of Physics, Virginia Commonwealth University, Richmond, VA 23284 (United States)

    2007-10-11

    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 {alpha}-{gamma} 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 {delta}-phase (fcc) in the phase diagram of Pu is another consequence of the border line behavior of the 5f electrons. The path leading from {delta}-Pu to {alpha}-Pu is identified.

  8. Rapid determination of alpha emitters using Actinide resin.

    Science.gov (United States)

    Navarro, N; Rodriguez, L; Alvarez, A; Sancho, C

    2004-01-01

    The European Commission has recently published the recommended radiological protection criteria for the clearance of building and building rubble from the dismantling of nuclear installations. Radionuclide specific clearance levels for actinides are very low (between 0.1 and 1 Bq g(-1)). The prevalence of natural radionuclides in rubble materials makes the verification of these levels by direct alpha counting impossible. The capability of Actinide resin (Eichrom Industries, Inc.) for extracting plutonium and americium from rubble samples has been tested in this work. Besides a strong affinity for actinides in the tri, tetra and hexavalent oxidation states, this extraction chromatographic resin presents an easy recovery of absorbed radionuclides. The retention capability was evaluated on rubble samples spiked with certified radionuclide standards (239Pu and 241Am). Samples were leached with nitric acid, passed through a chromatographic column containing the resin and the elution fraction was measured by LSC. Actinide retention varies from 60% to 80%. Based on these results, a rapid method for the verification of clearance levels for actinides in rubble samples is proposed. PMID:15177360

  9. Development of the Chalmers Grouped Actinide Extraction Process

    Directory of Open Access Journals (Sweden)

    Halleröd Jenny

    2015-12-01

    Full Text Available Several solvents for Grouped ActiNide EXtraction (GANEX processes have been investigated at Chalmers University of Technology in recent years. Four different GANEX solvents; cyclo-GANEX (CyMe4- -BTBP, 30 vol.% tri-butyl phosphate (TBP and cyclohexanone, DEHBA-GANEX (CyMe4-BTBP, 20 vol.% N,N-di-2(ethylhexyl butyramide (DEHBA and cyclohexanone, hexanol-GANEX (CyMe4-BTBP, 30 vol.% TBP and hexanol and FS-13-GANEX (CyMe4-BTBP, 30 vol.% TBP and phenyl trifluoromethyl sulfone (FS-13 have been studied and the results are discussed and compared in this work. The cyclohexanone based solvents show fast and high extraction of the actinides but a somewhat poor diluent stability in contact with the acidic aqueous phase. FS-13-GANEX display high separation factors between the actinides and lanthanides and a good radiolytic and hydrolytic stability. However, the distribution ratios of the actinides are lower, compared to the cyclohexanone based solvents. The hexanol-GANEX is a cheap solvent system using a rather stable diluent but the actinide extraction is, however, comparatively low.

  10. Feasibility studies of actinide recycle in LMFBRs as a waste management alternative

    International Nuclear Information System (INIS)

    A strategy of actinide burnup in LMFBRs is being investigated as a waste management alternative to long term storage of high level nuclear waste. This strategy is being evaluated because many of the actinides in the waste from spent-fuel reprocessing have half-lives of thousands of years and an alternative to geological storage may be desired. From a radiological viewpoint, the actinides and their daughters dominate the waste hazard for decay times beyond about 400 years. Actinide burnup in LMFBRs may be an attractive alternative to geological storage because the actinides can be effectively transmuted to fission products which have significantly shorter half-lives. Actinide burnup in LMFBRs rather than LWRs is preferred because the ratio of fission reaction rate to capture reaction rate for the actinides is higher in an LMFBR, and an LMFBR is not so sensitive to the addition of the actinide isotopes. An actinide target assembly recycle scheme is evaluated to determine the effects of the actinides on the LMFBR performance, including local power peaking, breeding ratio, and fissile material requirements. Several schemes are evaluated to identify any major problems associated with reprocessing and fabrication of recycle actinide-containing assemblies. The overall efficiency of actinide burnout in LMFBRs is evaluated, and equilibrium cycle conditions are determined. It is concluded that actinide recycle in LMFBRs offers an attractive alternative to long term storage of the actinides, and does not significantly affect the performance of the host LMFBR. Assuming a 0.1 percent or less actinide loss during reprocessing, a 0.1 percent loss of less during fabrication, and proper recycle schemes, virtually all of the actinides produced by a fission reactor economy could be transmuted in fast reactors

  11. Prompt Fission Neutron Spectra of Actinides

    Energy Technology Data Exchange (ETDEWEB)

    Capote, R; Chen, Y J; Hambsch, F J; Kornilov, N V; Lestone, J P; Litaize, O; Morillon, B; Neudecker, D; Oberstedt, S; Ohsawa, T; Smith, D. L.

    2016-01-01

    The energy spectrum of prompt neutrons emitted in fission (PFNS) plays a very important role in nuclear science and technology. A Coordinated Research Project (CRP) “Evaluation of Prompt Fission Neutron Spectra of Actinides”was established by the IAEA Nuclear Data Section in 2009, with the major goal to produce new PFNS evaluations with uncertainties for actinide nuclei. The following technical areas were addressed: (i) experiments and uncertainty quantification (UQ): New data for neutron-induced fission of 233U, 235U, 238U, and 239Pu have been measured, and older data have been compiled and reassessed. There is evidence from the experimental work of this CRP that a very small percentage of neutrons emitted in fission are actually scission neutrons; (ii) modeling: The Los Alamos model (LAM) continues to be the workhorse for PFNS evaluations. Monte Carlo models have been developed that describe the fission phenomena microscopically, but further development is needed to produce PFNS evaluations meeting the uncertainty targets; (iii) evaluation methodologies: PFNS evaluations rely on the use of the least-squares techniques for merging experimental and model data. Considerable insight was achieved on how to deal with the problem of too small uncertainties in PFNS evaluations. The importance of considering that all experimental PFNS data are “shape” data was stressed; (iv) PFNS evaluations: New evaluations, including covariance data, were generated for major actinides including 1) non-model GMA evaluations of the 235U(nth,f), 239Pu(nth,f), and 233U(nth,f) PFNS based exclusively on experimental data (0.02 ≤ E ≤ 10 MeV), which resulted in PFNS average energies E of 2.00±0.01, 2.073±0.010, and 2.030±0.013 MeV, respectively; 2) LAM evaluations of neutron-induced fission spectra on uranium and plutonium targets with improved UQ for incident energies from thermal up to 30 MeV; and 3) Point-by-Point calculations for 232Th, 234U and 237Np targets; and (v) data

  12. Actinide consumption: Nuclear resource conservation without breeding

    Energy Technology Data Exchange (ETDEWEB)

    Hannum, W.H.; Battles, J.E.; Johnson, T.R.; McPheeters, C.C.

    1991-01-01

    A new approach to the nuclear power issue based on a metallic fast reactor fuel and pyrometallurgical processing of spent fuel is showing great potential and is approaching a critical demonstration phase. If successful, this approach will complement and validate the LWR reactor systems and the attendant infrastructure (including repository development) and will alleviate the dominant concerns over the acceptability of nuclear power. The Integral Fast Reactor (IFR) concept is a metal-fueled, sodium-cooled pool-type fast reactor supported by a pyrometallurgical reprocessing system. The concept of a sodium cooled fast reactor is broadly demonstrated by the EBR-II and FFTF in the US; DFR and PFR in the UK; Phenix and SuperPhenix in France; BOR-60, BN-350, BN-600 in the USSR; and JOYO in Japan. The metallic fuel is an evolution from early EBR-II fuels. This fuel, a ternary U-Pu-Zr alloy, has been demonstrated to be highly reliable and fault tolerant even at very high burnup (160-180,000 MWd/MT). The fuel, coupled with the pool type reactor configuration, has been shown to have outstanding safety characteristics: even with all active safety systems disabled, such a reactor can survive a loss of coolant flow, a loss of heat sink, or other major accidents. Design studies based on a small modular approach show not only its impressive safety characteristics, but are projected to be economically competitive. The program to explore the feasibility of actinide recovery from spent LWR fuel is in its initial phase, but it is expected that technical feasibility could be demonstrated by about 1995; DOE has not yet committed funds to achieve this objective. 27 refs.

  13. Actinide consumption: Nuclear resource conservation without breeding

    International Nuclear Information System (INIS)

    A new approach to the nuclear power issue based on a metallic fast reactor fuel and pyrometallurgical processing of spent fuel is showing great potential and is approaching a critical demonstration phase. If successful, this approach will complement and validate the LWR reactor systems and the attendant infrastructure (including repository development) and will alleviate the dominant concerns over the acceptability of nuclear power. The Integral Fast Reactor (IFR) concept is a metal-fueled, sodium-cooled pool-type fast reactor supported by a pyrometallurgical reprocessing system. The concept of a sodium cooled fast reactor is broadly demonstrated by the EBR-II and FFTF in the US; DFR and PFR in the UK; Phenix and SuperPhenix in France; BOR-60, BN-350, BN-600 in the USSR; and JOYO in Japan. The metallic fuel is an evolution from early EBR-II fuels. This fuel, a ternary U-Pu-Zr alloy, has been demonstrated to be highly reliable and fault tolerant even at very high burnup (160-180,000 MWd/MT). The fuel, coupled with the pool type reactor configuration, has been shown to have outstanding safety characteristics: even with all active safety systems disabled, such a reactor can survive a loss of coolant flow, a loss of heat sink, or other major accidents. Design studies based on a small modular approach show not only its impressive safety characteristics, but are projected to be economically competitive. The program to explore the feasibility of actinide recovery from spent LWR fuel is in its initial phase, but it is expected that technical feasibility could be demonstrated by about 1995; DOE has not yet committed funds to achieve this objective. 27 refs

  14. 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)

    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

  15. Actinide-handling experience for training and education of future expert under J-ACTINET

    International Nuclear Information System (INIS)

    Summer schools for future experts have successfully been completed under Japan Actinide Network (J-ACTINET) for the purpose of development of human resources who are expected to be engaged in every areas of actinide-research/engineering. The first summer school was held in Ibaraki-area in August 2009, followed by the second one in Kansai-area in August 2010. Two summer schools have focused on actual experiences of actinides in actinide-research fields for university students and young researchers/engineers as an introductory course of actinide-researches. Many efforts were made to awaken interests into actinide-researches inside the participants during short periods of schools, 3 to 4 days. As actinides must be handled inside special apparatuses such as an air-tight globe-box with well-trained and qualified technicians, programs were optimized for effective experiences of actinides-handling. Several quasi actinide-handling experiences at the actinide-research fields have attracted attentions of participants at the first school in Ibaraki-area. The actual experiments using actinides-containing solutions have been carried out at the second school in Kansai-area. Future summer schools will be held every year for the sustainable human resource development in various actinide-research fields, together with other training and education programs conducted by the J-ACTINET. (author)

  16. Fluoride-conversion synthesis of homogeneous actinide oxide solid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Silva, G W Chinthaka M [ORNL; Hunn, John D [ORNL; Yeamans, Charles B. [University of California, Berkeley; Cerefice, Gary S. [University of Nevada, Las Vegas; Czerwinski, Ken R. [University of Nevada, Las Vegas

    2011-01-01

    Here, a novel route to synthesize (U, Th)O2 solid solutions at a relatively low temperature of 1100 C is demonstrated. First, the separate actinide oxides reacted with ammonium bifluoride to form ammonium actinide fluorides at room temperature. Subsequently, this mixture was converted to the actinide oxide solid solution using a two-phased heat treatment, first at 610 C in static air, then at 1100 C in flowing argon. Solid solutions obeying Vegard s Law were synthesized for ThO2 content from 10 to 90 wt%. Microscopy showed that the (U, Th)O2 solid solutions synthesized with this method to have considerably high crystallinity and homogeneity, suggesting the suitability of material thus synthesized for sintering into nuclear fuel pellets at low temperatures.

  17. Actinide (III) solubility in WIPP Brine: data summary and recommendations

    Energy Technology Data Exchange (ETDEWEB)

    Borkowski, Marian; Lucchini, Jean-Francois; Richmann, Michael K.; Reed, Donald T.

    2009-09-01

    The solubility of actinides in the +3 oxidation state is an important input into the Waste Isolation Pilot Plant (WIPP) performance assessment (PA) models that calculate potential actinide release from the WIPP repository. In this context, the solubility of neodymium(III) was determined as a function of pH, carbonate concentration, and WIPP brine composition. Additionally, we conducted a literature review on the solubility of +3 actinides under WIPP-related conditions. Neodymium(III) was used as a redox-invariant analog for the +3 oxidation state of americium and plutonium, which is the oxidation state that accounts for over 90% of the potential release from the WIPP through the dissolved brine release (DBR) mechanism, based on current WIPP performance assessment assumptions. These solubility data extend past studies to brine compositions that are more WIPP-relevant and cover a broader range of experimental conditions than past studies.

  18. Laser resonant-ionization mass spectrometry of actinides

    International Nuclear Information System (INIS)

    Laser resonant-ionization mass spectrometry has been used to determine small amounts of actinides. The high sensitivity and selectivity of this method has been achieved by three-step photoionization of actinide atoms followed by time-of-flight measurement. The laser system for photoionization consists of a pulsed copper vapour laser of 30 W average power at a pulse repetition rate of 6.5 kHz which is coupled to three dye lasers. The time-of-flight spectrometer has a mass resolution of about 2500. Resonance signals with count rates of several kilohertz were obtained with actinide samples of 1010-1012 atoms yielding a detection limit of 108 atoms in the sample. With some improvements a detection sensitivity of about 106 atoms of plutonium, americium and curium should be reached. (orig.)

  19. Synthesis of selective extractor for minor actinide elements

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Seung [Konyang University, Nonsan (Korea); Cho, Moon Hwan [Kangwon National University, Chunchon (Korea)

    1998-04-01

    To selectively co-separate the lanthanide and actinide elements (MA) such as Am or Cm ion from radioactive waste, synthesis of diamide derivatives has been accomplished. In addition, picoline amide derivatives were also synthesized for selectively separate the minor actinide elements from lanthanide elements. The content of research has don are as follows: (1) synthesis of diamide as co-extractant (2) introduction of n-tetradecyl to increase the lipophilicity (3) Picolyl chloride, intermediate of the final product, was synthesized by improved method rather than reported method. (4) The length of alkyl side chain was adjusted to increase the lipophilicity of free ligand and its derivatives able to selectively separate the actinide metal from lanthanide metal ions was successfully synthesized and determined their purity by analytical instruments. (author). 12 refs., 28 figs.

  20. Sequential determination of actinides in a variety of matrices

    International Nuclear Information System (INIS)

    A large number of analytical procedures for the actinides have been published, each catering for a specific need. Due to the bioassay programme in our laboratory, a need arose for a method to determine natural (Th and U) and anthropogenic actinides (Np, Pu and Am/Cm) together in a variety of samples. The method would have to be suitable for routine application: simple, inexpensive, rapid and robust. In some cases, the amount of material available is not sufficient for the determination of separate groups of actinides, and a sequential separation and measurement of the analytes would therefore be required. The types of matrices vary from aqueous samples to radiological surveillance (urine and faeces) to environmental studies (soil, sediment and fish), but the separation procedure should be able to service all of these. The working range of the method would have to cater for lower levels of the transuranium actinides in particular sample types containing higher levels of the natural actinides (U and Th). The first analytical problem to be discussed, is how to get the different sample types into the same loading solution required by a single separation approach. This entails sample dissolution or decomposition in some cases, and pre-concentration or pre-separation in others. A separation scheme is presented for the clean separation of all the actinides in a form suitable for alpha spectrometry. The development of a single column separation of the analytes of interest are looked at, as well as observations made during the development of the separation scheme, such as concentration effects. Results for test samples and certified reference materials are be presented. (author)

  1. Measurement of Actinides in Molybdenum-99 Solution Analytical Procedure

    Energy Technology Data Exchange (ETDEWEB)

    Soderquist, Chuck Z. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Weaver, Jamie L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-11-01

    This document is a companion report to a previous report, PNNL 24519, Measurement of Actinides in Molybdenum-99 Solution, A Brief Review of the Literature, August 2015. In this companion report, we report a fast, accurate, newly developed analytical method for measurement of trace alpha-emitting actinide elements in commercial high-activity molybdenum-99 solution. Molybdenum-99 is widely used to produce 99mTc for medical imaging. Because it is used as a radiopharmaceutical, its purity must be proven to be extremely high, particularly for the alpha emitting actinides. The sample of 99Mo solution is measured into a vessel (such as a polyethylene centrifuge tube) and acidified with dilute nitric acid. A gadolinium carrier is added (50 µg). Tracers and spikes are added as necessary. Then the solution is made strongly basic with ammonium hydroxide, which causes the gadolinium carrier to precipitate as hydrous Gd(OH)3. The precipitate of Gd(OH)3 carries all of the actinide elements. The suspension of gadolinium hydroxide is then passed through a membrane filter to make a counting mount suitable for direct alpha spectrometry. The high-activity 99Mo and 99mTc pass through the membrane filter and are separated from the alpha emitters. The gadolinium hydroxide, carrying any trace actinide elements that might be present in the sample, forms a thin, uniform cake on the surface of the membrane filter. The filter cake is first washed with dilute ammonium hydroxide to push the last traces of molybdate through, then with water. The filter is then mounted on a stainless steel counting disk. Finally, the alpha emitting actinide elements are measured by alpha spectrometry.

  2. Photochemical route to actinide-transition metal bonds: synthesis, characterization and reactivity of a series of thorium and uranium heterobimetallic complexes.

    Science.gov (United States)

    Ward, Ashleigh L; Lukens, Wayne W; Lu, Connie C; Arnold, John

    2014-03-01

    A series of actinide-transition metal heterobimetallics has been prepared, featuring thorium, uranium, and cobalt. Complexes incorporating the binucleating ligand N[ο-(NHCH2P(i)Pr2)C6H4]3 with either Th(IV) (4) or U(IV) (5) and a carbonyl bridged [Co(CO)4](-) unit were synthesized from the corresponding actinide chlorides (Th: 2; U: 3) and Na[Co(CO)4]. Irradiation of the resulting isocarbonyls with ultraviolet light resulted in the formation of new species containing actinide-metal bonds in good yields (Th: 6; U: 7); this photolysis method provides a new approach to a relatively unusual class of complexes. Characterization by single-crystal X-ray diffraction revealed that elimination of the bridging carbonyl and formation of the metal-metal bond is accompanied by coordination of a phosphine arm from the N4P3 ligand to the cobalt center. Additionally, actinide-cobalt bonds of 3.0771(5) Å and 3.0319(7) Å for the thorium and uranium complexes, respectively, were observed. The solution-state behavior of the thorium complexes was evaluated using (1)H, (1)H-(1)H COSY, (31)P, and variable-temperature NMR spectroscopy. IR, UV-vis/NIR, and variable-temperature magnetic susceptibility measurements are also reported.

  3. Analogue Study of Actinide Transport at Sites in Russia

    Energy Technology Data Exchange (ETDEWEB)

    Novikov, A P; Simmons, A M; Halsey, W G

    2003-02-12

    The U. S. Department of Energy (DOE) and the Russian Academy of Sciences (RAS) are engaged in a three-year cooperative study to observe the behavior of actinides in the natural environment at selected disposal sites and/or contamination sites in Russia. The purpose is to develop experimental data and models for actinide speciation, mobilization and transport processes in support of geologic repository design, safety and performance analyses. Currently at the mid-point of the study, the accomplishments to date include: evaluation of existing data and data needs, site screening and selection, initial data acquisition, and development of preliminary conceptual models.

  4. Thermally unstable complexants/phosphate mineralization of actinides

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-10-01

    In situ immobilization is an approach to isolation of radionuclides from the hydrosphere that is receiving increasing attention. Rather than removing the actinides from contaminated soils, this approach transforms the actinides into intrinsically insoluble mineral phases resistant to leaching by groundwater. The principal advangates of this concept are the low cost and low risk of operator exposure and/or dispersion of the radionuclides to the wider environment. The challenge of this approach is toe accomplish the immobilization without causing collateral damage to the environment (the cure shouldn`t be worse than the disease) and verification of system performance.

  5. INERT-MATRIX FUEL: ACTINIDE ''BURNING'' AND DIRECT DISPOSAL

    International Nuclear Information System (INIS)

    Excess actinides result from the dismantlement of nuclear weapons (Pu) and the reprocessing of commercial spent nuclear fuel (mainly 241 Am, 244 Cm and 237 Np). In Europe, Canada and Japan studies have determined much improved efficiencies for burnup of actinides using inert-matrix fuels. This innovative approach also considers the properties of the inert-matrix fuel as a nuclear waste form for direct disposal after one-cycle of burn-up. Direct disposal can considerably reduce cost, processing requirements, and radiation exposure to workers

  6. Production of heavy actinides in incomplete fusion reactions

    Science.gov (United States)

    Antonenko, N. V.; Cherepanov, E. A.; Iljinov, A. S.; Mebel, M. V.

    1994-10-01

    We present preliminary results of calculations by the phenomenological model of the estimated yield of some heavy actinide isotopes. It is assumed that these isotopes are produced as a result of multinucleon transfers followed by neutrons and charged particle emission A.S. Iljinov and E.A. Cherepanov (1980). The yield P(sub Z, N)(E*) of primary excited actinides is found using the model of N.V. Antonenko and R.V. Jolos (1991). Absolute cross-sections for different binary reaction channels are obtained by summing the cross-sections for all subchannels with an appreciable yield according to J. Wilczynski et al. (1980).

  7. In vivo measurement of actinides in the human lung

    International Nuclear Information System (INIS)

    The problems associated with the in vivo detection and measurement of actinides in the human lung are discussed together with various measurement systems currently in use. In particular, the methods and calibration procedures employed at the Lawrence Livermore Laboratory, namely, the use of twin Phoswich detectors and a new, more realistic, tissue-equivalent phantom, are described. Methods for the measurement of chest-wall thickness, fat content, and normal human background counts are also discussed. Detection-efficiency values and minimum detectable activity estimates are given for three common actinides, 238Pu, 239Pu, and 241Am

  8. Physics studies of higher actinide consumption in an LMR

    Energy Technology Data Exchange (ETDEWEB)

    Hill, R.N.; Wade, D.C.; Fujita, E.K.; Khalil, H.S.

    1990-01-01

    The core physics aspects of the transuranic burning potential of the Integral Fast Reactor (IFR) are assessed. The actinide behavior in fissile self-sufficient IFR closed cycles of 1200 MWt size is characterized, and the transuranic isotopics and risk potential of the working inventory are compared to those from a once-through LWR. The core neutronic performance effects of rare-earth impurities present in the recycled fuel are addressed. Fuel cycle strategies for burning transuranics from an external source are discussed, and specialized actinide burner designs are described. 4 refs., 4 figs., 3 tabs.

  9. Chemistry of tetravalent actinides phosphates. The thorium phosphate-diphosphate as immobilisation matrix of actinides

    International Nuclear Information System (INIS)

    The author presents in this document its scientific works from 1992 to 2001, in order to obtain the enabling to manage scientific and chemical researches at the university Paris Sud Orsay. The first part gives an abstract of the thesis on the characterizations, lixiviation and synthesis of uranium and thorium based phosphate matrix in the framework of the search for a ceramic material usable in the radioactive waste storage. The second part presents briefly the researches realized at the CEA, devoted to a reliable, independent and accurate measure of some isotopes activity. The last part presents the abstracts of researches activities from 1996 to 2001 on the tetravalent actinides phosphates chemistry, the sintering of PDT and solid solutions of PDTU and the kinetic and thermodynamical studies of the PDT dissolution. Many references and some publication in full text are provided. (A.L.B.)

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

    Indian Academy of Sciences (India)

    R Tripathi; S Sodaye; K Sudarshan

    2015-08-01

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

  11. Contribution to the physical modeling of the actinide characterization by electron probe microanalysis

    International Nuclear Information System (INIS)

    Electron probe microanalysis (EPMA) is used to quantify with a high accuracy the amount of different elements present on a sample of unknown composition. EPMA is largely used to quantify the amount of actinides present in fresh and irradiated fuels, to manage waste disposal and to date rocks. However, quantitative EPMA is not always possible to achieve for these materials due to the lack of suitable reference standards for the radionuclides. To overcome this difficulty, standard-less methods of analysis are employed with mean of virtual calculated standards. These calculated standards are generally obtained from empirical formulae based on experimental extrapolations or from theoretical calculations that require physical parameters which are poorly known as it is the case for the X-ray production cross section. The accurate knowledge of these cross sections is required in many applications such as in particle transport code and in Monte Carlo simulations. The computer simulations are widely used in the medical field and particularly in medical imaging and in electron beam therapy. In the field of astronomy, these data are used to perform simulations that predict the compositions of stars and galactic clouds, and the formation of planetary systems. In the present work, L- and M-shell absolute x-ray production cross sections were determined experimentally for elements lead, thorium and uranium by electron impact using ultrathin self-supporting targets with thickness varying from 0.2 to 8 nm. The measured cross sections have been compared, with the distorted-wave Born approximation (DWBA) calculated by Bote et al. and with the predictions of analytical formulae widely used in practical applications. For the conversion of inner-shell ionization cross sections into x-ray production cross sections, atomic relaxation parameters were extracted from the literature. The predictions of the DWBA calculations are in excellent agreement with our measured x-ray production cross

  12. 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)

  13. Advanced Recycling Reactor with Minor Actinide Fuel

    International Nuclear Information System (INIS)

    The Advanced Recycling Reactor (ARR) with minor actinide fuel has been studied. This paper presents the pre-conceptual design of the ARR proposed by the International Nuclear Recycling Alliance (INRA) for FOA study sponsored by DOE of the United States of America (U.S.). Although the basic reactor concept is technically mature, it is not suitable for commercial use due to the need to reduce capital costs. As a result of INRA's extensive experience, it is anticipated that a non-commercial ARR1 will be viable and meet U.S. requirements by 2025. Commercial Advanced Recycling Reactor (ARR) operations are expected to be feasible in competition with LWRs by 2050, based on construction of ARR2 in 2035. The ARR based on the Japan Sodium-cooled Fast Reactor (JSFR) is a loop-typed sodium cooled reactor with MOX fuel that is selected because of much experience of SFRs in the world. Major features of key technology enhancements incorporated into the ARR are the following: Decay heat can be removed by natural circulation to improve safety. The primary cooling system consists of two-loop system and the integrated IHX/Pump to improve economics. The steam generator with the straight double-walled tube is used to improve reliability. The reactor core of the ARR1 is 70 cm high and the volume fraction of fuel is 31.6%. The conversion ratio of fissile is set up less than 0.65 and the amount of burned TRU is 45-51 kg/TWeh. According to survey of more effective TRU burning core, the oxide fuel core containing high TRU (MA 15%, Pu 35% average) with moderate pins of 12% arranged driver fuel assemblies can decrease TRU conversion ratio to 0.33 and improve TRU burning capability to 67 kg/TWeh. The moderator can enhance TRU burning, while increasing the Doppler effect and reducing the positive sodium void effect. High TRU fraction promotes TRU burning by curbing plutonium production. High Am fraction and Am blanket promote Am transmutation. The ARR1 consists of a reactor building (including

  14. In-situ mineralization of actinides for groundwater cleanup: Laboratory demonstration with soil from the Fernald Environmental Management Project

    Energy Technology Data Exchange (ETDEWEB)

    Nash, K.L.; Jensen, M.P.; Schmidt, M.A. [Argonne National Lab., IL (United States). Chemistry Div.

    1997-11-01

    An attractive approach to decreasing the probability of actinide migration in the subsurface is to transform the ions into less mobile forms by remote treatment. The process described herein relies on a polyfunctional organophosphorus complexant to sequester the mobile metal ions by complexation/cation exchange in the near term. The cation exchanger is designed to subsequently decompose, transforming the actinides into insoluble phosphate mineral forms as the medium of stable long-term isolation. This material can be generated in situ in the subsurface thus eliminating the need for excavation to immobilize the actinide ions. Previous investigations have identified a suitable organophosphorus reagent and profiled its decomposition kinetics, verified the formation of phosphate mineral phases upon decomposition of the reagent, determined solubility limits for appropriate metal phosphates under groundwater conditions, and examined the cation exchange behavior of the calcium salt of the organophosphorus reagent. In this report, the focus is on a laboratory-scale demonstration of the concept using a soil sample from the Fernald Environmental Management Plant.

  15. The advanced liquid metal reactor actinide recycle system

    International Nuclear Information System (INIS)

    The current U.S. National Energy Strategy includes four key goals for nuclear policy: enhance safety and design standards, reduce economic risk, reduce regulatory risk, and establish an effective high-level nuclear waste program. The U.S. Department of Energy's Advanced Liquid Metal Reactor Actinide Recycle System is consistent with these objectives. The system has the ability to fulfill multiple missions with the same basic design concept. In addition to providing an option for long-term energy security, the system can be effectively utilized for recycling of actinides in light water reactor (LWR) spent fuel, provide waste management flexibility, including the reduction in the waste quantity and storage time and utilization of the available energy potential of LWR spent fuel. The actinide recycle system is comprised of (1) a compact liquid metal (sodium) cooled reactor system with optimized passive safety characteristics, and (2) pyrometallurgical metal fuel cycle presently under development of Argonne National Laboratory. The waste reduction of LWR spent fuel is accomplished by transmutation or fissioning of the longer-lived transuranic isotopes to shorter-lived fission products in the reactor. In this presentation the economical and environmental incentive of the actinide recycle system is addressed and the status of development including licensing aspects is described. 3 refs., 1 tab., 6 figs

  16. Preparation of actinide targets and sources using nonaqueous electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, M.M.; Gursky, J.C.; Wilhelmy, J.B. (Los Alamos National Lab., NM (USA))

    1991-05-15

    Application of the method of 'molecular plating' to prepare actinide targets suitable for accelerator bombardment is presented. Two example applications involving {sup 229}Th and {sup 254}Es are discussed along with the merits and liabilities of the method. (orig.).

  17. Surface energy and work function of the light actinides

    DEFF Research Database (Denmark)

    Kollár, J.; Vitos, Levente; Skriver, Hans Lomholt

    1994-01-01

    We have calculated the surface energy and work function of the light actinides Fr, Ra, Ac, Th, Pa, U, Np, and Pu by means of a Green's-function technique based on the linear-muffin-tin-orbitals method within the tight-binding representation. In these calculations we apply an energy functional whi...

  18. 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...

  19. RAPID SEPARATION OF ACTINIDES AND RADIOSTRONTIUM IN VEGETATION SAMPLES

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, S.

    2010-06-01

    A new rapid method for the determination of actinides and radiostrontium in vegetation samples has been developed at the Savannah River Site Environmental Lab (Aiken, SC, USA) that can be used in emergency response situations or for routine analysis. The actinides in vegetation method utilizes a rapid sodium hydroxide fusion method, a lanthanum fluoride matrix removal step, and a streamlined column separation process with stacked TEVA, TRU and DGA Resin cartridges. Lanthanum was separated rapidly and effectively from Am and Cm on DGA Resin. Alpha emitters are prepared using rare earth microprecipitation for counting by alpha spectrometry. The purified {sup 90}Sr fractions are mounted directly on planchets and counted by gas flow proportional counting. The method showed high chemical recoveries and effective removal of interferences. The actinide and {sup 90}Sr in vegetation sample analysis can be performed in less than 8 h with excellent quality for emergency samples. The rapid fusion technique is a rugged sample digestion method that ensures that any refractory actinide particles or vegetation residue after furnace heating is effectively digested.

  20. Functionalized pyrazines as ligands for minor actinide extraction and catalysis

    NARCIS (Netherlands)

    Nikishkin, N.

    2013-01-01

    The research presented in this thesis concerns the design of ligands for a wide range of applications, from nuclear waste treatment to catalysis. The strategies employed to design actinide-selective extractants, for instance, comprise the fine tuning of the ligand electronic properties as well as us

  1. Actinides How well do we know their stellar production?

    CERN Document Server

    Goriely, S

    2001-01-01

    The reliable evaluation of the r-process production of the actinides and careful estimates of the uncertainties affecting these predictions are key ingredients especially in nucleo-cosmochronology studies based on the analysis of very metal-poor stars or on the composition of meteorites. This type of information is also required in order to make the best possible use of future high precision data on the actinide composition of galactic cosmic rays, of the local interstellar medium, or of meteoritic grains of presumed circumstellar origin. This paper provides the practitioners in these various fields with the most detailed and careful analysis of the r-process actinide production available to-date. In total, thirty-two different multi-event canonical calculations using different nuclear ingredients or astrophysics conditions are presented, and are considered to give a fair picture of the level of reliability of the predictions of the actinide production, at least in the framework of a simple r-process model. T...

  2. Inhaled actinides: some safety issues and some research problems

    International Nuclear Information System (INIS)

    The following topics are discussed: limited research funds; risk coefficients for inhaled particles; the hot particle hypothesis; the Gofman-Martell contention; critical tissues for inhaled actinides inhalation hazards associated with future nuclear fuel cycles; and approach to be used by the inhalation panel

  3. Innovative SANEX process for trivalent actinides separation from PUREX raffinate

    International Nuclear Information System (INIS)

    Recycling of nuclear spent fuel and reduction of its radiotoxicity by separation of long-lived radionuclides would definitely help to close the nuclear fuel cycle ensuring sustainability of the nuclear energy. Partitioning of the main radiotoxicity contributors followed by their conversion into short-lived radioisotopes is known as partitioning and transmutation strategy. To ensure efficient transmutation of the separated elements (minor actinides) the content of lanthanides in the irradiation targets has to be minimised. This objective can be attained by solvent extraction using highly selective ligands that are able to separate these two groups of elements from each other. The objective of this study was to develop a novel process allowing co-separation of minor actinides and lanthanides from a high active acidic feed solution with subsequent actinide recovery using just one cycle, so-called innovative SANEX process. The conditions of each step of the process were optimised to ensure high actinide separation efficiency. Additionally, screening tests of several novel lipophilic and hydrophilic ligands provided by University of Twente were performed. These tests were aiming in better understanding the influence of the extractant structural modifications onto An(III)/Ln(III) selectivity and complexation properties. Optimal conditions for minor actinides separation were found and a flow-sheet of a new innovative SANEX process was proposed. Tests using a single centrifugal contactor confirmed high Eu(III)/Am(III) separation factor of 15 while the lowest SFLn/Am obtained was 6,5 (for neodymium). In addition, a new masking agent for zirconium was found as a substitution for oxalic acid. This new masking agent (CDTA) was also able to mask palladium without any negative influence on An(III)/Ln(III). Additional tests showed no influence of CDTA on plutonium present in the feed solution unlike oxalic acid which causes Pu precipitation. Therefore, CDTA was proposed as a Zr

  4. Assessment of Partitioning Processes for Transmutation of Actinides

    International Nuclear Information System (INIS)

    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

  5. Innovative SANEX process for trivalent actinides separation from PUREX raffinate

    Energy Technology Data Exchange (ETDEWEB)

    Sypula, Michal

    2013-07-01

    Recycling of nuclear spent fuel and reduction of its radiotoxicity by separation of long-lived radionuclides would definitely help to close the nuclear fuel cycle ensuring sustainability of the nuclear energy. Partitioning of the main radiotoxicity contributors followed by their conversion into short-lived radioisotopes is known as partitioning and transmutation strategy. To ensure efficient transmutation of the separated elements (minor actinides) the content of lanthanides in the irradiation targets has to be minimised. This objective can be attained by solvent extraction using highly selective ligands that are able to separate these two groups of elements from each other. The objective of this study was to develop a novel process allowing co-separation of minor actinides and lanthanides from a high active acidic feed solution with subsequent actinide recovery using just one cycle, so-called innovative SANEX process. The conditions of each step of the process were optimised to ensure high actinide separation efficiency. Additionally, screening tests of several novel lipophilic and hydrophilic ligands provided by University of Twente were performed. These tests were aiming in better understanding the influence of the extractant structural modifications onto An(III)/Ln(III) selectivity and complexation properties. Optimal conditions for minor actinides separation were found and a flow-sheet of a new innovative SANEX process was proposed. Tests using a single centrifugal contactor confirmed high Eu(III)/Am(III) separation factor of 15 while the lowest SF{sub Ln/Am} obtained was 6,5 (for neodymium). In addition, a new masking agent for zirconium was found as a substitution for oxalic acid. This new masking agent (CDTA) was also able to mask palladium without any negative influence on An(III)/Ln(III). Additional tests showed no influence of CDTA on plutonium present in the feed solution unlike oxalic acid which causes Pu precipitation. Therefore, CDTA was proposed as

  6. Sequestering agents for the removal of actinides from waste streams

    Energy Technology Data Exchange (ETDEWEB)

    Raymond, K.N.; White, D.J.; Xu, Jide; Mohs, T.R. [Univ. of California, Berkeley, CA (United States)

    1997-10-01

    The goal of this project is to take a biomimetic approach toward developing new separation technologies for the removal of radioactive elements from contaminated DOE sites. To achieve this objective, the authors are investigating the fundamental chemistry of naturally occurring, highly specific metal ion sequestering agents and developing them into liquid/liquid and solid supported actinide extraction agents. Nature produces sideophores (e.g., Enterobactin and Desferrioxamine B) to selectivity sequester Lewis acidic metal ions, in particular Fe(III), from its surroundings. These chelating agents typically use multiple catechols or hydroxamic acids to form polydentate ligands that chelate the metal ion forming very stable complexes. The authors are investigating and developing analogous molecules into selective chelators targeting actinide(IV) ions, which display similar properties to Fe(III). By taking advantage of differences in charge, preferred coordination number, and pH stability range, the transition from nature to actinide sequestering agents has been applied to the development of new and highly selective actinide extraction technologies. Additionally, the authors have shown that these chelating ligands are versatile ligands for chelating U(VI). In particular, they have been studying their coordination chemistry and fundamental interactions with the uranyl ion [UO{sub 2}]{sup 2+}, the dominant form of uranium found in aqueous media. With an understanding of this chemistry, and results obtained from in vivo uranium sequestration studies, it should be possible to apply these actinide(IV) extraction technologies to the development of new extraction agents for the removal of uranium from waste streams.

  7. Actinide partitioning-transmutation program final report. I. Overall assessment

    International Nuclear Information System (INIS)

    This report is concerned with an overall assessment of the feasibility of and incentives for partitioning (recovering) long-lived nuclides from fuel reprocessing and fuel refabrication plant radioactive wastes and transmuting them to shorter-lived or stable nuclides by neutron irradiation. The principal class of nuclides considered is the actinides, although a brief analysis is given of the partitioning and transmutation (P-T) of 99Tc and 129I. The results obtained in this program permit us to make a comparison of the impacts of waste management with and without actinide recovery and transmutation. Three major conclusions concerning technical feasibility can be drawn from the assessment: (1) actinide P-T is feasible, subject to the acceptability of fuels containing recycle actinides; (2) technetium P-T is feasible if satisfactory partitioning processes can be developed and satisfactory fuels identified (no studies have been made in this area); and (3) iodine P-T is marginally feasible at best because of the low transmutation rates, the high volatility, and the corrosiveness of iodine and iodine compounds. It was concluded on the basis of a very conservative repository risk analysis that there are no safety or cost incentives for actinide P-T. In fact, if nonradiological risks are included, the short-term risks of P-T exceed the long-term benefits integrated over a period of 1 million years. Incentives for technetium and iodine P-T exist only if extremely conservative long-term risk analyses are used. Further RD and D in support of P-T is not warranted

  8. Speciation of actinides by the mean of synchrotron radiation; Speciation des actinides au moyen du rayonnement synchrotron

    Energy Technology Data Exchange (ETDEWEB)

    Simoni, E. [Institut de Physique Nucleaire, (IN2P3/CNRS) 91 - Orsay (France); Den Auwer, Ch. [CEA Marcoule, Dept. Radiochimie et Procedes (DRCP/SCPS), 30 (France)

    2005-09-01

    After having recalled the principle of the X absorption spectroscopy, the authors give examples illustrating the analytical possibilities of this technique and the different application fields concerning the actinides physico-chemistry (coordination chemistry, interface, solid state, solution). (O.M.)

  9. Actinide immobilization in the subsurface environment by in-situ treatment with a hydrolytically unstable organophosphorus complexant: Uranyl uptake by calcium phytate

    Energy Technology Data Exchange (ETDEWEB)

    Nash, K.L.; Jensen, M.P.; Schmidt, M.A.

    1997-12-31

    In addition to naturally occurring uranium and thorium, actinide ions exist in the subsurface environment as a result of accidental releases and intentional disposal practices associated with nuclear weapons production. These species present a significant challenge to cost-effective remediation of contaminated environments. An attractive approach to decreasing the probability of actinide migration in the subsurface is to transform the ions into a less mobile form by remote treatment. We have under development a process which relies on a polyfunctional organophosphorus complexant to sequester the mobile metal ions by complexation/cation exchange in the near term, and to subsequently decompose, transforming the actinides into insoluble phosphate mineral forms in the long term. Studies to date include identification of a suitable organophosphorus reagent, profiling of its decomposition kinetics, verification of the formation of phosphate mineral phases upon decomposition of the reagent, and extensive comparison of the actinide uptake ability of the calcium salt of the reagent as compared with hydroxyapatite. In this report, we briefly describe the process with focus on the cation exchange behavior of the calcium salt of the organophosphorus sequestrant.

  10. Photochemical route to actinide-transition metal bonds: synthesis, characterization and reactivity of a series of thorium and uranium heterobimetallic complexes

    Energy Technology Data Exchange (ETDEWEB)

    Ward, Ashleigh; Lukens, Wayne; Lu, Connie; Arnold, John

    2014-04-01

    A series of actinide-transition metal heterobimetallics has been prepared, featuring thorium, uranium and cobalt. Complexes incorporating the binucleating ligand N[-(NHCH2PiPr2)C6H4]3 and Th(IV) (4) or U(IV) (5) with a carbonyl bridged [Co(CO)4]- unit were synthesized from the corresponding actinide chlorides (Th: 2; U: 3) and Na[Co(CO)4]. Irradiation of the isocarbonyls with ultraviolet light resulted in the formation of new species containing actinide-metal bonds in good yields (Th: 6; U: 7); this photolysis method provides a new approach to a relatively rare class of complexes. Characterization by single-crystal X-ray diffraction revealed that elimination of the bridging carbonyl is accompanied by coordination of a phosphine arm from the N4P3 ligand to the cobalt center. Additionally, actinide-cobalt bonds of 3.0771(5) and 3.0319(7) for the thorium and uranium complexes, respectively, were observed. The solution state behavior of the thorium complexes was evaluated using 1H, 1H-1H COSY, 31P and variable-temperature NMR spectroscopy. IR, UV-Vis/NIR, and variable-temperature magnetic susceptibility measurements are also reported.

  11. Internal contamination by actinides after wounding: a robust rodent model for assessment of local and distant actinide retention.

    Science.gov (United States)

    Griffiths, N M; Wilk, J C; Abram, M C; Renault, D; Chau, Q; Helfer, N; Guichet, C; Van der Meeren, A

    2012-08-01

    Internal contamination by actinides following wounding may occur in nuclear fuel industry workers or subsequent to terrorist activities, causing dissemination of radioactive elements. Contamination by alpha particle emitting actinides can result in pathological effects, either local or distant from the site of entry. The objective of the present study was to develop a robust experimental approach in the rat for short- and long- term actinide contamination following wounding by incision of the skin and muscles of the hind limb. Anesthetized rats were contaminated with Mixed OXide (MOX, uranium, plutonium oxides containing 7.1% plutonium) or plutonium nitrate (Pu nitrate) following wounding by deep incision of the hind leg. Actinide excretion and tissue levels were measured as well as histological changes from 2 h to 3 mo. Humid swabs were used for rapid evaluation of contamination levels and proved to be an initial guide for contamination levels. Although the activity transferred from wound to blood is higher after contamination with a moderately soluble form of plutonium (nitrate), at 7 d most of the MOX (98%) or Pu nitrate (87%) was retained at the wound site. Rapid actinide retention in liver and bone was observed within 24 h, which increased up to 3 mo. After MOX contamination, a more rapid initial urinary excretion of americium was observed compared with plutonium. At 3 mo, around 95% of activity remained at the wound site, and excretion of Pu and Am was extremely low. This experimental approach could be applied to other situations involving contamination following wounding including rupture of the dermal, vascular, and muscle barriers.

  12. Actinides: How well do we know their stellar production?

    Science.gov (United States)

    Goriely, S.; Arnould, M.

    2001-12-01

    The reliable evaluation of the r-process production of the actinides and careful estimates of the uncertainties affecting these predictions are key ingredients especially in nucleo-cosmochronology studies based on the analysis of very metal-poor stars or on the composition of meteorites. This type of information is also required in order to make the best possible use of future high precision data on the actinide composition of galactic cosmic rays, of the local interstellar medium, or of meteoritic grains of presumed circumstellar origin. This paper provides the practitioners in these various fields with the most detailed and careful analysis of the r-process actinide production available to-date. This study is based on a version of the multi-event canonical model of the r-process which discards the largely used waiting point approximation. It considers also different combinations of models for the calculation of nuclear masses, beta -decay and fission rates. Two variants of the model used to predict nuclear reaction rates are adopted. In addition, the influence of the level of Pb and Bi production by the r-process on the estimated actinide production is evaluated by relying on the solar abundances of these two elements. In total, thirty-two different cases are presented, and are considered to give a fair picture of the level of reliability of the predictions of the actinide production, at least in the framework of a simple r-process model. This simplicity is imposed by our inability to identify the proper astrophysical sites for the r-process. As a guide to the practitioners, constraints on the actinide yield predictions and associated uncertainties are suggested on grounds of the measured abundances of r-nuclides, including Th and U, in the star CS 31082-001, and under the critical and questionable assumption of the ``universality'' of the r-process. We also define alternative constraints based on the nucleo-cosmochronological results derived from the present

  13. Physical nature of longevity of light actinides in dynamic failure phenomenon

    Science.gov (United States)

    Uchaev, A. Ya.; Punin, V. T.; Selchenkova, N. I.; Kosheleva, E. V.; Kosachev, V. V.

    2015-12-01

    It is shown in this work that the physical nature of the longevity of light actinides under extreme conditions in a range of nonequilibrium states of t ~ 10-6-10-10 s is determined by the time needed for the formation of a critical concentration of a cascade of failure centers, which changes connectivity of the body. These centers form a percolation cluster. The longevity is composed of waiting time t w for the appearance of failure centers and clusterization time t c of cascade of failure centers, when connectivity in the system of failure centers and the percolation cluster arise. A unique mechanism of the dynamic failure process, a unique order parameter, and an equal dimensionality of the space in which the process occurs determine the physical nature of the longevity of metals, including fissionable materials.

  14. Physical nature of longevity of light actinides in dynamic failure phenomenon

    Energy Technology Data Exchange (ETDEWEB)

    Uchaev, A. Ya., E-mail: uchaev@expd.vniief.ru; Punin, V. T.; Selchenkova, N. I.; Kosheleva, E. V. [Russian Federal Nuclear Center—VNIIEF (Russian Federation); Kosachev, V. V. [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) (Russian Federation)

    2015-12-15

    It is shown in this work that the physical nature of the longevity of light actinides under extreme conditions in a range of nonequilibrium states of t ∼ 10{sup –6}–10{sup –10} s is determined by the time needed for the formation of a critical concentration of a cascade of failure centers, which changes connectivity of the body. These centers form a percolation cluster. The longevity is composed of waiting time t{sub w} for the appearance of failure centers and clusterization time t{sub c} of cascade of failure centers, when connectivity in the system of failure centers and the percolation cluster arise. A unique mechanism of the dynamic failure process, a unique order parameter, and an equal dimensionality of the space in which the process occurs determine the physical nature of the longevity of metals, including fissionable materials.

  15. Solubility of actinides and surrogates in nuclear glasses; Solubilite des actinides et de leurs simulants dans les verres nucleaires. Limites d'incorporation et comprehension des mecanismes

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, Ch

    2003-07-01

    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{sub 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)

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

    Science.gov (United States)

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

    2014-09-01

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

  17. Actinides and fission products partitioning from high level liquid waste

    International Nuclear Information System (INIS)

    The presence of small amount of mixed actinides and long-lived heat generators fission products as 137Cs and 90Sr are the major problems for safety handling and disposal of high level nuclear wastes. In this work, actinides and fission products partitioning process, as an alternative process for waste treatment is proposed. First of all, ammonium phosphotungstate (PWA), a selective inorganic exchanger for cesium separation was chosen and a new procedure for synthesizing PWA into the organic resin was developed. An strong anionic resin loaded with tungstate or phosphotungstate anion enables the precipitation of PWA directly in the resinous structure by adding the ammonium nitrate in acid medium (R-PWA). Parameters as W/P ratio, pH, reactants, temperature and aging were studied. The R-PWA obtained by using phosphotungstate solution prepared with W/P=9.6, 9 hours digestion time at 94-106 deg C and 4 to 5 months aging time showed the best capacity for cesium retention. On the other hand, Sr separation was performed by technique of extraction chromatography, using DH18C6 impregnated on XAD7 resin as stationary phase. Sr is selectively extracted from acid solution and >99% was recovered from loaded column using distilled water as eluent. Concerning to actinides separations, two extraction chromatographic columns were used. In the first one, TBP(XAD7) column, U and Pu were extracted and its separations were carried-out using HNO3 and hydroxylamine nitrate + HNO3 as eluent. In the second one, CMP0-TBP(XAD7) column, the actinides were retained on the column and the separations were done by using (NH4)2C2O4 , DTPA, HNO3 and HCl as eluent. The behavior of some fission products were also verified in both columns. Based on the obtained data, actinides and fission products Cs and Sr partitioning process, using TBP(XAD7) and CMP0-TBP(XAD7) columns for actinides separation, R-PWA column for cesium retention and DH18C6(XAD7) column for Sr isolation was performed. (author)

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

    International Nuclear Information System (INIS)

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

  19. Predictions of Actinide Solubilities under Near-Field Conditions Expected in the WIPP

    Science.gov (United States)

    Brush, L. H.; Xiong, Y.

    2009-12-01

    The Waste Isolation Pilot Plant (WIPP) is a U.S. Department of Energy (DOE) repository in southeast New Mexico for defense-related transuranic (TRU) waste. The repository, which opened in March 1999, is located at a subsurface depth of 655 m (2150 ft) in the Salado Fm., a Permian bedded-salt formation. The repository will eventually contain the equivalent of 844,000 208 L (55 gal) drums of TRU waste. After filling the rooms and access drifts and installing panel closures, creep closure of the salt will crush the steel waste containers in most cases and encapsulate the waste. The WIPP actinide source term model used for long-term performance assessment (PA) of the repository comprises dissolved and suspended submodels (solubilities and colloids). This presentation will describe the solubilities. From the standpoint of long-term PA, the order of importance of the radioelements in the TRU waste to be emplaced in the WIPP is Pu ~ Am >> U > Th >> Np ~ Cm and fission products. The DOE has included all of these actinides, but not fission products, in the WIPP Actinide Source Term Program (ASTP). Anoxic corrosion of Fe- and Al-base metals and microbial consumption of cellulosic, plastic, and rubber materials will produce gas and create strongly reducing conditions in the WIPP after closure. The use of MgO as an engineered barrier to consume microbially produced CO2 will result in low fCO2 and basic pH. Under these conditions, Th, U, Np, Pu, and Am will speciate essentially entirely as Th(IV), U(IV), Np(IV), Pu(III), and Am(III); or Th(IV), U(VI), Np(V), Pu(IV), and Am(III). The DOE has developed thermodynamic speciation-and-solubility models for +III, +IV, and +V actinides in brines. Experimental data for Nd, Am, and Cm species were used to parameterize the +III Pitzer activity-coefficient model; data for Th species were used for the +IV model; and data for Np(V) species were used for the +V model. These models include the effects of the organic ligands acetate, citrate

  20. Computation of actinide pourbaix diagrams at 298 K and 550 K (U,Np,Pu,Am,Cm - H{sub 2}O)

    Energy Technology Data Exchange (ETDEWEB)

    Piro, M.H.; Bruni, G.M.F.; Lewis, B.J.; Thompson, W.T., E-mail: thompson-w@rmc.ca [Royal Military College of Canada, Dept. of Chemistry and Chemical Engineering, Kingston, Ontario (Canada); Iglesias, F.C. [Candesco Corp., Toronto, Ontario (Canada); Guoping, M.A.; Nashiem, R. [Bruce Power Limited., Tiverton, Ontario (Canada); Roberts, J.G. [Cantech Associates Limited, Burlington, Ontario (Canada)

    2011-07-01

    Pourbaix diagrams for the actinides ranging from uranium to curium have been developed from the enthalpy of formation, entropy and heat capacity (or estimates thereof) for the phases and aqueous species. Emphasis has been given to the region between hydrogen and oxygen gas saturation.Additional thermodynamic computations illustrate how the data may be employed in better understanding the chemical behaviour of fuel debris circulating in CANDU reactor coolant. (author)

  1. Actinide coordination chemistry: towards the limits of the periodic table; Chimie de coordination des actinides: vers les frontieres du tableau periodique

    Energy Technology Data Exchange (ETDEWEB)

    Den Auwer, C.; Moisy, P. [CEA Marcoule (DEN/DRCP/SCPS), 30 (France); Simoni, E. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire

    2009-05-15

    Actinide elements represent a distinct chemical family at the bottom of the periodic table. Among the major characteristics of this 14 element family is their high atomic numbers and their radioactivity. Actinide chemistry finds its roots in the history of the 20. century and plays a very important role in our contemporary world. Energetic as well as technical challenges are facing the development of nuclear energy. In this pedagogical introduction to actinide chemistry, the authors draw a comparison between the actinides family and the chemistry of two other families, lanthanides and transition metals. This article focuses on molecular and aqueous chemistry. It has been based on class notes aiming to present an overview of the chemical diversity of actinides, and its future challenges for modern science. (authors)

  2. Investigating Actinide Molecular Adducts From Absorption Edge Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Den Auwer, C.; Conradson, S.D.; Guilbaud, P.; Moisy, P.; Mustre de Leon, J.; Simoni, E.; /SLAC, SSRL

    2006-10-27

    Although Absorption Edge Spectroscopy has been widely applied to the speciation of actinide elements, specifically at the L{sub III} edge, understanding and interpretation of actinide edge spectra are not complete. In that sense, semi-quantitative analysis is scarce. In this paper, different aspects of edge simulation are presented, including semi-quantitative approaches. Comparison is made between various actinyl (U, Np) aquo or hydroxy compounds. An excursion into transition metal osmium chemistry allows us to compare the structurally related osmyl and uranyl hydroxides. The edge shape and characteristic features are discussed within the multiple scattering picture and the role of the first coordination sphere as well as contributions from the water solvent are described.

  3. Review of Integral Experiments for Minor Actinide Management

    International Nuclear Information System (INIS)

    Spent nuclear fuel contains minor actinides (MAs) such as neptunium, americium and curium, which require careful management. This becomes even more important when mixed oxide (MOX) fuel is being used on a large scale since more MAs will accumulate in the spent fuel. One way to manage these MAs is to transmute them in nuclear reactors, including in light water reactors, fast reactors or accelerator-driven subcritical systems. The transmutation of MAs, however, is not straightforward, as the loading of MAs generally affects physics parameters, such as coolant void, Doppler and burn-up reactivity. This report focuses on nuclear data requirements for minor actinide management, the review of existing integral data and the determination of required experimental work, the identification of bottlenecks and possible solutions, and the recommendation of an action programme for international co-operation. (authors)

  4. Accuracy Improvement of Neutron Nuclear Data on Minor Actinides

    Directory of Open Access Journals (Sweden)

    Harada Hideo

    2015-01-01

    Full Text Available Improvement of accuracy of neutron nuclear data for minor actinides (MAs and long-lived fission products (LLFPs is required for developing innovative nuclear system transmuting these nuclei. In order to meet the requirement, the project entitled as “Research and development for Accuracy Improvement of neutron nuclear data on Minor ACtinides (AIMAC” has been started as one of the “Innovative Nuclear Research and Development Program” in Japan at October 2013. The AIMAC project team is composed of researchers in four different fields: differential nuclear data measurement, integral nuclear data measurement, nuclear chemistry, and nuclear data evaluation. By integrating all of the forefront knowledge and techniques in these fields, the team aims at improving the accuracy of the data. The background and research plan of the AIMAC project are presented.

  5. Preparation of isotopes and sources of actinide elements

    International Nuclear Information System (INIS)

    As the C.E.A. possesses no isotopic separation facility, the productions of isotopes of actinide elements are performed: a) by neutron irradiation and chemical treatment of special targets, b) by milking decay products from stocks of aged actinide elements, c) by chemical treatment of alpha active wastes. These productions concern the following isotopes: 233U, 238Pu, 242Pu, 243Cm, 242Cm, 244Cm (a); 228Th, 229Th, 234U, 237U, 239Np, 240Pu, 241Am, 248Cm (b); 237Np, 241Am (c). These isotopes are produced to satisfy French and international needs and are sent to users in various forms: solutions, metals, oxides, fluorides, or in different sources forms. The preparation of the sources represents an important field of activities divided into two parts: 1/Industrial sources: production of large series of different sources, 2/ Scientific sources: production of sources suitable for a specific scientific problem. A large overview of these activities is given

  6. Superabsorbing gel for actinide, lanthanide, and fission product decontamination

    Energy Technology Data Exchange (ETDEWEB)

    Kaminski, Michael D.; Mertz, Carol J.

    2016-06-07

    The present invention provides an aqueous gel composition for removing actinide ions, lanthanide ions, fission product ions, or a combination thereof from a porous surface contaminated therewith. The composition comprises a polymer mixture comprising a gel forming cross-linked polymer and a linear polymer. The linear polymer is present at a concentration that is less than the concentration of the cross-linked polymer. The polymer mixture is at least about 95% hydrated with an aqueous solution comprising about 0.1 to about 3 percent by weight (wt %) of a multi-dentate organic acid chelating agent, and about 0.02 to about 0.6 molar (M) carbonate salt, to form a gel. When applied to a porous surface contaminated with actinide ions, lanthanide ions, and/or other fission product ions, the aqueous gel absorbs contaminating ions from the surface.

  7. Lanthanide and actinide complexation studies with tetradentate 'N' donor ligands

    International Nuclear Information System (INIS)

    Because of their similar charge and chemical behaviour separation of trivalent actinides and lanthanides is an important and challenging task in nuclear fuel cycle. Soft (S,N) donor ligands show selectivity towards the trivalent actinides over the lanthanides. Out of various 'N' donor ligands studied, bis(1,2,4)triazinyl bipyridine (BTBP) and bis(1,2,4)triazinyl phenanthroline (BTPhen) were found to be most promising. In order to understand the separation behaviour of these ligands, their complexation studies with these 'f' block elements are essential. In the present work, complexation studies of various lanthanide ions (La3+, Eu3+ and Er3+) was studied with ethyl derivatives of BTBP (C2BTBP) and BTBPhen (C2BTPhen) and pentyl derivative of BTBP (C5BTBP) in acetonitrile medium using UV-Vis spectrophotometry, fluorescence spectroscopy and solution calorimetry. Computational studies were also carried out to understand the experimental results

  8. The effects of corrosion product colloids on actinide transport

    International Nuclear Information System (INIS)

    This report assesses the possible effects of colloidal corrosion products on the transport of actinides from the near field of radioactive waste repositories. The desorption of plutonium and americium from colloidal corrosion products of iron and zirconium was studied under conditions simulating a transition from near-field to far-field environmental conditions. Desorption of actinides occurred slowly from the colloids under far-field conditions. Measurements of particle stability showed all the colloids to be unstable in the near field. Stability increased under far-field conditions or as a result of the evolution of the near field. Migration of colloids from the near field is unlikely except in the presence of organic materials. (Author)

  9. Evaluation of prompt neutron spectra for minor actinide nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Ohsawa, Takaaki [Kinki Univ., Higashi-Osaka, Osaka (Japan). Atomic Energy Research Inst.

    1997-03-01

    Measurement data on fission prompt neutron spectra of minor actinide (MA) is much little, and its accuracy is also unsufficient. Therefore, conventional evaluation value of fission spectra of MA was assumed for its nuclear temperature by using a method of determining from its systemicity owing to assumption of the Maxwell type distribution, but it can be said that this method consider fully to features of MA isotopes. In this paper, some evaluation calculation results are shown by adopting an evaluation method developed by authors and based on modified Madland Nix model and are conducted by concept of physical properties on target nuclei. As a result, by adopting the level density parameter of fission fragments, the inverse process cross section, the fission product yield distribution and the total release energy, effect of inverse process cross section, mass distribution of fission product, calculation results of Cm isotope and systemicity of fission spectra of actinide isotope were investigated. (G.K.)

  10. X-Ray Absorption Spectroscopy of the Actinides

    Science.gov (United States)

    Antonio, Mark R.; Soderholm, Lynda

    The recent availability of synchrotron radiation has revolutionized actinide chemistry. This is particularly true in environmental studies, where heterogeneous samples add to the already multifaceted chemistry exhibited by these ions. Environmental samples are often inhomogeneous, chemically diverse, and amorphous or poorly crystalline. Even surrogates prepared in the laboratory to simplify the natural complexity are plagued by multiple oxidation state and varied coordination polyhedra that are a reflection of inherent 5f chemistry. For example, plutonium can be found as Pu3+ Pu4+ Pu(V)O2 +, and Pu(VI)O2 2 + within naturally occurring pH-Eh conditions, consequently complex equilibria are found between these oxidation states in one solution. In addition, dissolved actinides have significant affinities for various mineral surfaces, to which they can adsorb with or without concomitant reduction-oxidation (redox) activity, depending on details of the solution and surface conditions.

  11. Status of measurements of fission neutron spectra of Minor Actinides

    Energy Technology Data Exchange (ETDEWEB)

    Drapchinsky, L.; Shiryaev, B. [V.G. Khlopin Radium Inst., Saint Petersburg (Russian Federation)

    1997-03-01

    The report considers experimental and theoretical works on studying the energy spectra of prompt neutrons emitted in spontaneous fission and neutron induced fission of Minor Actinides. It is noted that neutron spectra investigations were done for only a small number of such nuclei, most measurements, except those of Cf-252, having been carried out long ago by obsolete methods and imperfectapparatus. The works have no detailed description of experiments, analysis of errors, detailed numerical information about results of experiments. A conclusion is made that the available data do not come up to modern requirements. It is necessary to make new measurements of fission prompt neutron spectra of transuranium nuclides important for the objectives of working out a conception of minor actinides transmutation by means of special reactors. (author)

  12. Actinide-specific sequestering agents and decontamination applications

    Energy Technology Data Exchange (ETDEWEB)

    Smith, William L. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials and Molecular Research Division; Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Raymond, Kenneth N. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials and Molecular Research Division; Univ. of California, Berkeley, CA (United States). Dept. of Chemistry

    1981-04-07

    With the commercial development of nuclear reactors, the actinides have become very important industrial elements. A major concern of the nuclear industry is the biological hazard associated with nuclear fuels and their wastes. The acute chemical toxicity of tetravalent actinides, as exemplified by Th(IV), is similar to Cr(III) or Al(III). However, the acute toxicity of 239Pu(IV) is similar to strychnine, which is much more toxic than any of the non-radioactive metals such as mercury. Although the more radioactive isotopes of the transuranium elements are more acutely toxic by weight than plutonium, the acute toxicities of 239Pu, 241Am, and 244Cm are nearly identical in radiation dose, ~100 μCi/kg in rodents. Finally and thus, the extreme acute toxicity of 239Pu is attributed to its high specific activity of alpha emission.

  13. 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.

  14. Molecular Characterization of Actinide Oxocations from Protactinium to Plutonium

    International Nuclear Information System (INIS)

    This presentation addresses the structural characterization by EXAFS of actinide cations at oxidation states (V) and (VI) as one walks across the periodic table from Z = 91 (protactinium) to Z = 94 (plutonium). A structural comparison between Pa, U, Np and Pu oxocations in aqueous solution at formal oxidation states (V) and (VI) is carried out. These results are corroborated by quantum chemical and molecular dynamics calculations

  15. Validation of minor actinides fission neutron cross-sections

    Directory of Open Access Journals (Sweden)

    Pešić Milan P.

    2015-01-01

    Full Text Available Verification of neutron fission cross-sections of minor actinides from some recently available evaluated nuclear data libraries was carried out by comparison of the reaction rates calculated by the MCNP6.1 computer code to the experimental values. The experimental samples, containing thin layers of 235U, 237Np, 238,239,240,241Pu, 242mAm, 243Cm, 245Cm, and 247Cm, deposited on metal support and foils of 235U (pseudo-alloy 27Al + 235U, 238U, natIn, 64Zn, 27Al, and multi-component sample alloy 27Al + 55Mn + natCu + natLu + 197Au, were irradiated in the channels of the tank containing fluorine salts 0.52NaF + 0.48ZrF4, labelled as the Micromodel Salt Blanket, inserted in the lattice centre of the MAKET heavy water critical assembly at the Institute for Theoretical and Experimental Physics, Moscow. This paper is a continuation of earlier initiated scientific-research activities carried out for validation of the evaluated fission cross-sections of actinides that were supposed to be used for the quality examination of the fuel design of the accelerator driven systems or fast reactors, and consequently, determination of transmutation rates of actinides, and therefore, determination of operation parameters of these reactor facilities. These scientific-research activities were carried out within a frame of scientific projects supported by the International Science and Technology Center and the International Atomic Energy Agency co-ordinated research activities, from 1999 to 2010. Obtained results confirm that further research is needed in evaluations in order to establish better neutron cross-section data for the minor actinides and selected nuclides which could be used in the accelerator driven systems or fast reactors.

  16. EXAFS studies of actinide ions in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Karim, D P; Georgopoulos, P; Knapp, G S

    1979-01-01

    The applicability of the EXAFS technique in the study of actinide systems is discussed. Uranium L/sub III/-edge spectra obtained on an in-lab rotating anode EXAFS facility are presented and analyzed for crystalline UO/sub 2/F/sub 2/ and aqueous solutions containing hexavalent uranium ions. Methods for the extension of the technique to more dilute systems are discussed.

  17. Chemical and Ceramic Methods Toward Safe Storage of Actinides

    Energy Technology Data Exchange (ETDEWEB)

    P.E.D. Morgan; R.M. Housley; J.B. Davis; M.L. DeHaan

    2005-08-19

    A very import, extremely-long-term, use for monazite as a radwaste encapsulant has been proposed. THe use of ceramic La-monazite for sequestering actinides (isolating them from the environment), especially plutonium and some other radioactive elements )e.g., fission-product rare earths), had been especially championed by Lynn Boatner of ORNL. Monazite may be used alone or, copying its compatibility with many other minerals in nature, may be used in diverse composite combinations.

  18. Chemical properties of the heavier actinides and transactinides

    International Nuclear Information System (INIS)

    The chemical properties of each of the elements 99 (Es) through 105 are reviewed and their properties correlated with the electronic structure expected for 5f and 6d elements. A major feature of the heavier actinides, which differentiates them from the comparable lanthanides, is the increasing stability of the divalent oxidation state with increasing atomic number. The divalent oxidation state first becomes observable in the anhydrous halides of californium and increases in stability through the series to nobelium, where this valency becomes predominant in aqueous solution. In comparison with the analogous 4f electrons, the 5f electrons in the latter part of the series are more tightly bound. Thus, there is a lowering of the 5f energy levels with respect to the Fermi level as the atomic number increases. The metallic state of the heavier actinides has not been investigated except from the viewpoint of the relative volatility among members of the series. In aqueous solutions, ions of these elements behave as a normal trivalent actinides and lanthanides (except for nobelium). Their ionic radii decrease with increasing nuclear charge which is moderated because of increased screening of the outer 6p electrons by the 5f electrons. The actinide series of elements is completed with the element lawrencium (Lr) in which the electronic configuration is 5f147s27p. From Mendeleev's periodicity and Dirac-Fock calculations, the next group of elements is expected to be a d-transition series corresponding to the elements Hf through Hg. The chemical properties of elements 104 and 105 only have been studied and they indeed appear to show the properties expected of eka-Hf and eka-Ta. However, their nuclear lifetimes are so short and so few atoms can be produced that a rich variety of chemical information is probably unobtainable

  19. Prediction of thermodynamic properties of actinide and lanthanide compounds

    Institute of Scientific and Technical Information of China (English)

    LU Chunhai; NI Shijun; SUN Ying; CHEN Wenkai; ZHANG Chengjiang

    2008-01-01

    Several relationship models for thermodynamic functions of actinide and lanthanide compounds are built. The descriptors such as the difference of atomic radii between metal atoms and nonmetal atoms and the molecular mass are used in quantitative structure-activity/property relationships. The relative errors for entropy and heat capacity are less than 20% in the majority of gaseous compounds. Similar results are obtained from solid compounds.

  20. Analytical applications of superacid dissolution of actinide and lanthanide substrates

    International Nuclear Information System (INIS)

    The superacid system HF/SbF5 is extraordinarily effective for total dissolution of actinide and lanthanide ceramic oxides, fluorides, and metals. Optical or gamma spectroscopy can be used directly on the solutions. Evaporation of the HF/SbF5 solvent under vacuum leaves a residue which is easily dissolved by ordinary mineral acids. The resulting aqueous solutions are readily amenable to conventional analytical methods. (author) 14 refs.; 1 tab

  1. Chemical and Ceramic Methods Toward Safe Storage of Actinides

    International Nuclear Information System (INIS)

    A very important, extremely-long-term, use for monazite as a radwaste encapsulant has been proposed. The use of ceramic La-monazite for sequestering actinides (isolating them from the environment), especially plutonium and some other radioactive elements (e.g., fission-product rare earths), had been especially championed by Lynn Boatner of ORNL. Monazite may be used alone or, copying its compatibility with many other minerals in nature, may be used in diverse composite combinations

  2. Chemical properties of the heavier actinides and transactinides

    Energy Technology Data Exchange (ETDEWEB)

    Hulet, E.K.

    1981-01-01

    The chemical properties of each of the elements 99 (Es) through 105 are reviewed and their properties correlated with the electronic structure expected for 5f and 6d elements. A major feature of the heavier actinides, which differentiates them from the comparable lanthanides, is the increasing stability of the divalent oxidation state with increasing atomic number. The divalent oxidation state first becomes observable in the anhydrous halides of californium and increases in stability through the series to nobelium, where this valency becomes predominant in aqueous solution. In comparison with the analogous 4f electrons, the 5f electrons in the latter part of the series are more tightly bound. Thus, there is a lowering of the 5f energy levels with respect to the Fermi level as the atomic number increases. The metallic state of the heavier actinides has not been investigated except from the viewpoint of the relative volatility among members of the series. In aqueous solutions, ions of these elements behave as a normal trivalent actinides and lanthanides (except for nobelium). Their ionic radii decrease with increasing nuclear charge which is moderated because of increased screening of the outer 6p electrons by the 5f electrons. The actinide series of elements is completed with the element lawrencium (Lr) in which the electronic configuration is 5f/sup 14/7s/sup 2/7p. From Mendeleev's periodicity and Dirac-Fock calculations, the next group of elements is expected to be a d-transition series corresponding to the elements Hf through Hg. The chemical properties of elements 104 and 105 only have been studied and they indeed appear to show the properties expected of eka-Hf and eka-Ta. However, their nuclear lifetimes are so short and so few atoms can be produced that a rich variety of chemical information is probably unobtainable.

  3. Impact of actinide recycle on nuclear fuel cycle health risks

    International Nuclear Information System (INIS)

    The purpose of this background paper is to summarize what is presently known about potential impacts on the impacts on the health risk of the nuclear fuel cycle form deployment of the Advanced Liquid Metal Reactor (ALMR)1 and Integral Fast Reactor (IF)2 technology as an actinide burning system. In a companion paper the impact on waste repository risk is addressed in some detail. Therefore, this paper focuses on the remainder of the fuel cycle

  4. Molecular Characterization of Actinide Oxocations from Protactinium to Plutonium

    Science.gov (United States)

    Den Auwer, C.; Guilbaud, P.; Guillaumont, D.; Moisy, P.; Digandomenico, V.; Le Naour, C.; Trubert, D.; Simoni, E.; Hennig, C.; Scheinost, A.; Conradson, S. D.

    2007-02-01

    This presentation addresses the structural characterization by EXAFS of actinide cations at oxidation states (V) and (VI) as one walks across the periodic table from Z = 91 (protactinium) to Z = 94 (plutonium). A structural comparison between Pa, U, Np and Pu oxocations in aqueous solution at formal oxidation states (V) and (VI) is carried out. These results are corroborated by quantum chemical and molecular dynamics calculations.

  5. ACTINIDE-SPECIFIC SEQUESTERING AGENTS AND DECONTAMINATION APPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Smith, William L.; Raymond, Kenneth N.

    1980-07-01

    We have briefly reviewed the biological hazards associated with the actinide elements. The most abundant transuranium element produced by both industrial nuclear power plants and nuclear weapons programs is plutonium. It is also potentially the most toxic - particularly due to its long-term hazard as a carcinogen if it is introduced into the body. This toxicity is due in large part to the chemical and biochemical similarities of Pu(IV) and Fe(III). Thus in mammals plutonium is transported and stored by the transport and storage systems for iron. This results in the concentration and long-term retention of an alpha-emitting radionuclide ({sup 239}Pu) at sites such as the bone marrow where cell division occurs at a high rate. The earliest attempts at removal of actinide contamination by chelation therapy were essentially heuristic in that sequestering agents known to be effective at binding other elements were tried with plutonium. The research described here is intended to be a rational approach that begins with the observation that since Fe(III) and Pu(IV) are so similar, and since microbes produce agents called siderophores that are extremely effective and selective sequestering agents for Fe(III), the construction of similar chelating agents for the actinides should be possible using the same chelating groups found in the siderophores. The incorporation of four such groups (primarily catechol and hydroxamic acid) results in multidentate chelating agents that can completely encapsulate the central actinide(IV) ion and achieve the eight-coordinate environment most favored by such ions. The continuing development and improvement of such sequestering agents has produced compounds which remove significant amounts of plutonium deposited in bone and which remove a greater fraction of the total body burden than any other chelation therapy developed to date.

  6. Future nuclear fuel cycles: Prospect and challenges for actinide recycling

    Science.gov (United States)

    Warin, Dominique

    2010-03-01

    The global energy context pleads in favour of a sustainable development of nuclear energy since the demand for energy will likely increase, whereas resources will tend to get scarcer and the prospect of global warming will drive down the consumption of fossil fuel. In this context, nuclear power has the worldwide potential to curtail the dependence on fossil fuels and thereby to reduce the amount of greenhouse gas emissions while promoting energy independence. How we deal with nuclear radioactive waste is crucial in this context. In France, the public's concern regarding the long-term waste management made the French Governments to prepare and pass the 1991 and 2006 Acts, requesting in particular the study of applicable solutions for still minimizing the quantity and the hazardousness of final waste. This necessitates High Active Long Life element (such as the Minor Actinides MA) recycling, since the results of fuel cycle R&D could significantly change the challenges for the storage of nuclear waste. HALL recycling can reduce the heat load and the half-life of most of the waste to be buried to a couple of hundred years, overcoming the concerns of the public related to the long-life of the waste and thus aiding the "burying approach" in securing a "broadly agreed political consensus" of waste disposal in a geological repository. This paper presents an overview of the recent R and D results obtained at the CEA Atalante facility on innovative actinide partitioning hydrometallurgical processes. For americium and curium partitioning, these results concern improvements and possible simplifications of the Diamex-Sanex process, whose technical feasibility was already demonstrated in 2005. Results on the first tests of the Ganex process (grouped actinide separation for homogeneous recycling) are also discussed. In the coming years, next steps will involve both better in-depth understanding of the basis of these actinide partitioning processes and, for the new promising

  7. Molecular cluster theory of chemical bonding in actinide oxide

    International Nuclear Information System (INIS)

    The electronic structure of actinide monoxides AcO and dioxides AcO2, 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 AcO10-6 and AcO12-8 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 NpO6 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

  8. Crystalline matrices for the immobilization of plutonium and actinides

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, E.B.; Burakov, E.E.; Galkin, Ya.B.; Starchenko, V.A.; Vasiliev, V.G. [V.G. Khlopin Radium Institute, St. Petersburg (Russian Federation)

    1996-05-01

    The management of weapon plutonium, disengaged as a result of conversion, is considered together with the problem of the actinide fraction of long-lived high level radioactive wastes. It is proposed to use polymineral ceramics based on crystalline host-phases: zircon ZrSiO{sub 4} and zirconium dioxide ZrO{sub 2}, for various variants of the management of plutonium and actinides (including the purposes of long-term safe storage or final disposal from the human activity sphere). It is shown that plutonium and actinides are able to form with these phases on ZrSiO{sub 4} and ZrO{sub 2} was done on laboratory level by the hot pressing method, using the plasmochemical calcination technology. To incorporate simulators of plutonium into the structure of ZrSiO{sub 4} and ZrO{sub 2} in the course of synthesis, an original method developed by the authors as a result of studying the high-uranium zircon (Zr,U) SiO{sub 4} form Chernobyl {open_quotes}lavas{close_quotes} was used.

  9. The chemical thermodynamics of actinide elements and compounds

    International Nuclear Information System (INIS)

    This compilation forms the twelfth part of a comprehensive assessment and selection of actinide thermodynamic data. The other parts of the compilation deal mostly with actinide elements and compounds. This part, which is the last one to be published in this Series, concerns inorganic actinide complexes in aqueous solution. The properties considered include the stability constant as a function of ionic strength and temperature and, whenever possible, enthalpy and entropy values. The present assessment is based on a literature survey that was terminated in early 1989. In tabulating literature data, only experimental results were used; estimates as well as recalculated data were ignored. Unlike in previous assessments of this kind in this assessment the selection of a best value is discussed and justified, and reasons are given for the rejection of data. In addition, our estimates of the thermodynamic properties, based on interrelationships between analogous systems, are given when this can be done reliably. Another essential aim of this assessment is to indicate those areas in which additional research is required. Refs

  10. Toward laser ablation Accelerator Mass Spectrometry of actinides

    Science.gov (United States)

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

    2013-01-01

    A project to measure neutron capture cross sections of a number of actinides in a reactor environment by Accelerator Mass Spectrometry (AMS) at the ATLAS facility of Argonne National Laboratory is underway. This project will require the precise and accurate measurement of produced actinide isotopes in many (>30) samples irradiated in the Advanced Test Reactor at Idaho National Laboratory with neutron fluxes having different energy distributions. The AMS technique at ATLAS is based on production of highly-charged positive ions in an electron cyclotron resonance (ECR) ion source followed by acceleration in the ATLAS linac and mass-to-charge (m/q) measurement at the focus of the Fragment Mass Analyzer. Laser ablation was selected as the method of feeding the actinide material into the ion source because we expect it will have higher efficiency and lower chamber contamination than either the oven or sputtering techniques, because of a much narrower angular distribution of emitted material. In addition, a new multi-sample holder/changer to allow quick change between samples and a computer-controlled routine allowing fast tuning of the accelerator for different beams, are being developed. An initial test run studying backgrounds, detector response, and accelerator scaling repeatability was conducted in December 2010. The project design, schedule, and results of the initial test run to study backgrounds are discussed.

  11. Value of 236U to actinide-only burnup credit

    International Nuclear Information System (INIS)

    The US Department of Energy (DOE) submitted a topical report to the US Nuclear Regulatory Commission (NRC) in May 1995 in order to gain approval of a method for criticality analysis of transport packages that takes account for the change in actinide isotopes with burnup [pressurized water reactors (PWRs) only]. Historically, the NRC has conservatively assumed that the fuel was in its initial conditions (without any burnable absorbers). In order to permit credit for the changes in actinide content, the NRC has required validation of the depletion and criticality codes for spent nuclear fuel, justification of conservative depletion modeling, and finally confirmation measurements before loading. The NRC requested additional information on March 22, 1996. The DOE responded by a revision of the topical report in May 1997. The NRC again responded with another set of requests of additional information in April 1998. In that set of questions, the NRC challenged the use of 236U in burnup credit. Uranium-236 is not found in any significant amount in any available critical experiments. The authors explore the value of 236U to actinide-only burnup credit

  12. RAPID SEPARATION METHOD FOR ACTINIDES IN EMERGENCY AIR FILTER SAMPLES

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, S.; Noyes, G.; Culligan, B.

    2010-02-03

    A new rapid method for the determination of actinides and strontium in air filter samples has been developed at the Savannah River Site Environmental Lab (Aiken, SC, USA) that can be used in emergency response situations. The actinides and strontium in air filter method utilizes a rapid acid digestion method and a streamlined column separation process with stacked TEVA, TRU and Sr Resin cartridges. Vacuum box technology and rapid flow rates are used to reduce analytical time. Alpha emitters are prepared using cerium fluoride microprecipitation for counting by alpha spectrometry. The purified {sup 90}Sr fractions are mounted directly on planchets and counted by gas flow proportional counting. The method showed high chemical recoveries and effective removal of interferences. This new procedure was applied to emergency air filter samples received in the NRIP Emergency Response exercise administered by the National Institute for Standards and Technology (NIST) in April, 2009. The actinide and {sup 90}Sr in air filter results were reported in {approx}4 hours with excellent quality.

  13. Behavior of actinides in the Integral Fast Reactor fuel cycle

    Energy Technology Data Exchange (ETDEWEB)

    Courtney, J.C. [Louisiana State Univ., Baton Rouge, LA (United States). Nuclear Science Center; Lineberry, M.J. [Argonne National Lab., Idaho Falls, ID (United States). Technology Development Div.

    1994-06-01

    The Integral Fast Reactor (IFR) under development by Argonne National Laboratory uses metallic fuels instead of ceramics. This allows electrorefining of spent fuels and presents opportunities for recycling minor actinide elements. Four minor actinides ({sup 237}Np, {sup 240}Pu, {sup 241}Am, and {sup 243}Am) determine the waste storage requirements of spent fuel from all types of fission reactors. These nuclides behave the same as uranium and other plutonium isotopes in electrorefining, so they can be recycled back to the reactor without elaborate chemical processing. An experiment has been designed to demonstrate the effectiveness of the high-energy neutron spectra of the IFR in consuming these four nuclides and plutonium. Eighteen sets of seven actinide and five light metal targets have been selected for ten day exposure in the Experimental Breeder Reactor-2 which serves as a prototype of the IFR. Post-irradiation analyses of the exposed targets by gamma, alpha, and mass spectroscopy are used to determine nuclear reaction-rates and neutron spectra. These experimental data increase the authors` confidence in their ability to predict reaction rates in candidate IFR designs using a variety of neutron transport and diffusion programs.

  14. 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...... of competing localized and delocalized f-electron configurations underlies the ground states of NpC, PuC, AmC, NpN, and PuN. The fully localized 5f-electron configuration is realized in CmC (f7), CmN (f7), and AmN (f6). The observed sudden increase in lattice parameter from PuN to AmN is found to be related...... increasing degree of f electron localization from U to Cm, with the tendency toward localization being slightly stronger in the (more ionic) nitrides compared to the (more covalent) carbides. The itinerant band picture is found to be adequate for UC and acceptable for UN, while a more complex manifold...

  15. 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, which...... for AO2 and A2O3 is found to follow the stoichiometry, namely, corresponding to A4+ ions in the dioxide and A3+ ions in the sesquioxides. In contrast, the A2+ ionic configuration is not favorable in the monoxides, which therefore become metallic. The energetics of the oxidation and reduction...... in the actinide dioxides is discussed, and it is found that the dioxide is the most stable oxide for the actinides from Np onward. Our study reveals a strong link between preferred oxidation number and degree of localization which is confirmed by comparing to the ground-state configurations of the corresponding...

  16. 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)

  17. Investigations of actinides in the context of final disposal of high-level radioactive waste - trivalent actinides in aqueous solution

    International Nuclear Information System (INIS)

    This contribution presents a small piece of research work at KIT-INE dealing with the speciation of redox sensitive trivalent actinides like Pu(III), Np(III), and U(III) in aqueous solution. The redox preparation, stabilization, and speciation of trivalent actinide in aqueous systems are discussed here. The reductants investigated were rongalite, HYA (hydroxylamine hydrochloride), and AHA (acetohydroxamic acid). The time dependence of An(III) stability at different pH values was investigated. The An(III) species in aqueous solution have been characterized by UV-Vis and XANES spectroscopy. A broader overview of the work at KIT-INE is given in the oral presentation at the NUCAR2013 conference. (author)

  18. Factors affecting actinide solubility in a repository for spent fuel, 1

    International Nuclear Information System (INIS)

    The main tasks in the study were to get information on the chemical conditions in a repository for spent fuel and information on factors affecting releases of actinides from spent fuel and solubility of actinides in a repository for spent fuel. The work in this field started at the Reactor Laboratory of the Technical Research Centre of Finland (VTT) in 1982. This is a report on the effects on the main parameters, Eh, pH, carbonate, organic compounds, colloids, microbes and radiation on the actinide solubility in the nearfield of the repository. Another task has been to identify available models and reported experience from actinide solubility calculations with different codes. 167 refs

  19. Utilization of Minor Actinides (Np, Am, Cm) in Nuclear Power Reactor

    Science.gov (United States)

    Gerasimov, A.; Bergelson, B.; Tikhomirov, G.

    2014-06-01

    Calculation research of the utilization process of minor actinides (transmutation with use of power released) is performed for specialized power reactor of the VVER type operating on the level of electric power of 1000 MW. Five subsequent cycles are considered for the reactor with fuel elements containing minor actinides along with enriched uranium. It was shown that one specialized reactor for the one cycle (900 days) can utilize minor actinides from several VVER-1000 reactors without any technological and structural modifications. Power released because of minor actinide fission is about 4% with respect to the total power

  20. Multidimensionally constrained relativistic mean-field study of triple-humped barriers in actinides

    Science.gov (United States)

    Zhao, Jie; Lu, Bing-Nan; Vretenar, Dario; Zhao, En-Guang; Zhou, Shan-Gui

    2015-01-01

    Background: Potential energy surfaces (PES's) of actinide nuclei are characterized by a two-humped barrier structure. At large deformations beyond the second barrier, the occurrence of a third barrier was predicted by macroscopic-microscopic model calculations in the 1970s, but contradictory results were later reported by a number of studies that used different methods. Purpose: Triple-humped barriers in actinide nuclei are investigated in the framework of covariant density functional theory (CDFT). Methods: Calculations are performed using the multidimensionally constrained relativistic mean field (MDC-RMF) model, with the nonlinear point-coupling functional PC-PK1 and the density-dependent meson exchange functional DD-ME2 in the particle-hole channel. Pairing correlations are treated in the BCS approximation with a separable pairing force of finite range. Results: Two-dimensional PES's of 226,228,230,232Th and 232,235,236,238U are mapped and the third minima on these surfaces are located. Then one-dimensional potential energy curves along the fission path are analyzed in detail and the energies of the second barrier, the third minimum, and the third barrier are determined. The functional DD-ME2 predicts the occurrence of a third barrier in all Th nuclei and 238U . The third minima in 230 ,232Th are very shallow, whereas those in 226 ,228Th and 238U are quite prominent. With the functional PC-PK1 a third barrier is found only in 226 ,228 ,230Th . Single-nucleon levels around the Fermi surface are analyzed in 226Th, and it is found that the formation of the third minimum is mainly due to the Z =90 proton energy gap at β20≈1.5 and β30≈0.7 . Conclusions: The possible occurrence of a third barrier on the PES's of actinide nuclei depends on the effective interaction used in multidimensional CDFT calculations. More pronounced minima are predicted by the DD-ME2 functional, as compared to the functional PC-PK1. The depth of the third well in Th isotopes decreases

  1. Advanced processes for minor actinides recycling: studies towards potential industrialization

    International Nuclear Information System (INIS)

    In June 2006, a new act on sustainable management of radioactive waste was voted by the French parliament with a national plan on radioactive materials and radioactive waste management (PNG-MDR). Concerning partitioning and transmutation, the program is connected to 4. generation reactors, in which transmutation of minor actinides could be operated. In this frame, the next important milestone is 2012, with the assessment of the possible transmutation roads, which are either homogeneous recycling of the minor actinides in the whole reactor fleet, with a low content of M.A (∼3%) in all fuel assemblies, or heterogeneous recycling of the minor actinides in about one third of the reactor park, with a higher content of M.A. (∼20%) in dedicated targets dispatched in the periphery of the reactor. Advanced processes for the recycling of minor actinides are being developed to address the challenges of these various management options. An important part of the program consists in getting closer to process implementation conditions. The processes based on liquid-liquid extraction benefit from the experience gained by operating the PUREX process at the La Hague plant. In the field of extracting apparatus, a large experience is available. In the field of extracting apparatus, a large experience is already available. Nevertheless, the processes present specificities which have to be considered more precisely. They have been classified in the following fields: - Evolution of the simulation codes, including phenomenological representations: with such a simulation tool, it will be possible to assess operating tolerances, lead sensitivity studies and calculate transient states; - Definition of the implementation conditions in continuous contactors (such as pulse columns), according to the extractant physico-chemical characteristics; - Scale-up of new extractants, such as malonamides used in the DIAMEX process, facing purity specifications and costs estimation; - Solvent clean

  2. A systematic study of actinide production from the interactions of heavy ions with sup 248 Cm

    Energy Technology Data Exchange (ETDEWEB)

    Leyba, J.D.

    1990-09-07

    Production cross sections for heavy actinides produced from the interactions of {sup 12}C, {sup 31}P, {sup 40}Ar, and {sup 44}Ca ions with {sup 248}Cm were measured at energies ranging from 0.98 to 1.35 X Coulomb barrier. The recoiling reaction products were collected in copper or gold catcher foils located near the {sup 248}Cm target. Separate fractions of Bk, Cf, Es, Fm, and Md were obtained from a radiochemical separation procedure. For the {sup 12}C system, a He/KCl jet was used to transport the recoiling No activities of interest to a rotating wheel system. The isotopic distributions of the actinide products were found to be essentially symmetric about the maximum with full-widths-at-half-maximum of approximately 2.5 mass units. Isotopic distributions of the {sup 12}C, {sup 31}P, {sup 40}Ar, and {sup 44}Ca systems were found to be very similar to the {sup 40,48}Ca systems studied previously. The maxima of the isotopic distributions generally occurred for those reaction channels which involved the exchange of the fewest number of nucleons between the target and projectile for which the calculated excitation energy was a positive quantity. Additionally, the maxima of the excitation functions occurred at those projectile energies which were consistent with the calculated reaction barriers based upon a binary reaction mechanism. The experimental data from the four systems investigated were compared to several models of heavy ion interactions including a damped reaction mechanism, compound nucleus formation and subsequent particle evaporation, and classical partial wave calculations for binary systems.

  3. A systematic study of actinide production from the interactions of heavy ions with 248Cm

    International Nuclear Information System (INIS)

    Production cross sections for heavy actinides produced from the interactions of 12C, 31P, 40Ar, and 44Ca ions with 248Cm were measured at energies ranging from 0.98 to 1.35 X Coulomb barrier. The recoiling reaction products were collected in copper or gold catcher foils located near the 248Cm target. Separate fractions of Bk, Cf, Es, Fm, and Md were obtained from a radiochemical separation procedure. For the 12C system, a He/KCl jet was used to transport the recoiling No activities of interest to a rotating wheel system. The isotopic distributions of the actinide products were found to be essentially symmetric about the maximum with full-widths-at-half-maximum of approximately 2.5 mass units. Isotopic distributions of the 12C, 31P, 40Ar, and 44Ca systems were found to be very similar to the 40,48Ca systems studied previously. The maxima of the isotopic distributions generally occurred for those reaction channels which involved the exchange of the fewest number of nucleons between the target and projectile for which the calculated excitation energy was a positive quantity. Additionally, the maxima of the excitation functions occurred at those projectile energies which were consistent with the calculated reaction barriers based upon a binary reaction mechanism. The experimental data from the four systems investigated were compared to several models of heavy ion interactions including a damped reaction mechanism, compound nucleus formation and subsequent particle evaporation, and classical partial wave calculations for binary systems

  4. Separation of actinides from irradiated An–Zr based fuel by electrorefining on solid aluminium cathodes in molten LiCl–KCl

    International Nuclear Information System (INIS)

    Highlights: • Electrorefining process in molten LiCl-KCl using solid Al electrodes was demonstrated. • High separation factors of actinides over lanthanides were achieved. • Efficient recovery of actinides from irradiated nuclear fuel was achieved. • Uniform, dense and well adhered deposits were obtained and characterised. • Kinetic parameters of actinide–aluminium alloy formation were evaluated. - Abstract: An electrorefining process for metallic spent nuclear fuel treatment is being investigated in ITU. Solid aluminium cathodes are used for homogeneous recovery of all actinides within the process carried out in molten LiCl–KCl eutectic salt at a temperature of 500 °C. As the selectivity, efficiency and performance of solid Al has been already shown using un-irradiated An–Zr alloy based test fuels, the present work was focused on laboratory-scale demonstration of the process using irradiated METAPHIX-1 fuel composed of U67–Pu19–Zr10–MA2–RE2 (wt.%, MA = Np, Am, Cm, RE = Nd, Ce, Gd, Y). Different electrorefining techniques, conditions and cathode geometries were used during the experiment yielding evaluation of separation factors, kinetic parameters of actinide–aluminium alloy formation, process efficiency and macro-structure characterisation of the deposits. The results confirmed an excellent separation and very high efficiency of the electrorefining process using solid Al cathodes

  5. Separation of actinides from irradiated An–Zr based fuel by electrorefining on solid aluminium cathodes in molten LiCl–KCl

    Energy Technology Data Exchange (ETDEWEB)

    Souček, P., E-mail: Pavel.Soucek@ec.europa.eu [European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Postfach 2340, 76125 Karlsruhe (Germany); Murakami, T. [Central Research Institute of Electric Power Industry (CRIEPI), Komae-shi, Tokyo 201-8511 (Japan); Claux, B.; Meier, R.; Malmbeck, R. [European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Postfach 2340, 76125 Karlsruhe (Germany); Tsukada, T. [Central Research Institute of Electric Power Industry (CRIEPI), Komae-shi, Tokyo 201-8511 (Japan); Glatz, J.-P. [European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Postfach 2340, 76125 Karlsruhe (Germany)

    2015-04-15

    Highlights: • Electrorefining process in molten LiCl-KCl using solid Al electrodes was demonstrated. • High separation factors of actinides over lanthanides were achieved. • Efficient recovery of actinides from irradiated nuclear fuel was achieved. • Uniform, dense and well adhered deposits were obtained and characterised. • Kinetic parameters of actinide–aluminium alloy formation were evaluated. - Abstract: An electrorefining process for metallic spent nuclear fuel treatment is being investigated in ITU. Solid aluminium cathodes are used for homogeneous recovery of all actinides within the process carried out in molten LiCl–KCl eutectic salt at a temperature of 500 °C. As the selectivity, efficiency and performance of solid Al has been already shown using un-irradiated An–Zr alloy based test fuels, the present work was focused on laboratory-scale demonstration of the process using irradiated METAPHIX-1 fuel composed of U{sub 67}–Pu{sub 19}–Zr{sub 10}–MA{sub 2}–RE{sub 2} (wt.%, MA = Np, Am, Cm, RE = Nd, Ce, Gd, Y). Different electrorefining techniques, conditions and cathode geometries were used during the experiment yielding evaluation of separation factors, kinetic parameters of actinide–aluminium alloy formation, process efficiency and macro-structure characterisation of the deposits. The results confirmed an excellent separation and very high efficiency of the electrorefining process using solid Al cathodes.

  6. ACTINET-I3 Summer School on Analytical Innovation in the field of actinide recycling - Slides of the presentations

    International Nuclear Information System (INIS)

    This conference dealt with 3 main topics: analytical innovation in separation processes (hyphenated techniques, analytical chips,...), actinide recycling (extraction, interfaces, processes,...) and chemistry and thermodynamics of actinides. This document is composed of the slides of the presentations

  7. Systematic Characteristics of Fast Neutron Fission Cross Sections for Actinide Nuclei

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The neutron fission cross sections of actinide nuclei are important data for the design of nuclear reactor and nuclear engineering, and so on. So far, there has been a certain amount of experimental data for the fission cross sections of actinide nuclei. However,

  8. Actinide Partitioning and Transmutation Program. Progress report, April 1--June 30, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Tedder, D. W.; Blomeke, J. O. [comps.

    1977-10-01

    Experimental work on the 16 tasks comprising the Actinide Partitioning and Transmutation Program was continued. Summaries of work are given on Purex Process modifications, actinide recovery, Am-Cm recovery, radiation effects on ion exchangers, LMFBR transmutation studies, thermal reactor transmutation studies, fuel cycle studies, and partitioning-transmutation evaluation. (JRD)

  9. Mathematical modelling of the effects of aerobic and anaerobic chelate biodegradation on actinide speciation

    International Nuclear Information System (INIS)

    Biodegradation of natural and anthropogenic chelating agents directly and indirectly affects the speciation, and hence, the mobility of actinides in subsurface environments. We combined mathematical modelling with laboratory experimentation to investigate the effects of aerobic and anaerobic chelate biodegradation on actinide [Np(IV/V), Pu(IV)] speciation. Under aerobic conditions, nitrilotriacetic acid (NTA) biodegradation rates were strongly influenced by the actinide concentration. Actinide-chelate complexation reduced the relative abundance of available growth substrate in solution and actinide species present or released during chelate degradation were toxic to the organisms. Aerobic bioutilization of the chelates as electron-donor substrates directly affected actinide speciation by releasing the radionuclides from complexed form into solution, where their fate was controlled by inorganic ligands in the system. Actinide speciation was also indirectly affected by pH changes caused by organic biodegradation. The two concurrent processes of organic biodegradation and actinide aqueous chemistry were accurately linked and described using CCBATCH, a computer model developed at Northwestern University to investigate the dynamics of coupled biological and chemical reactions in mixed waste subsurface environments. CCBATCH was then used to simulate the fate of Np during anaerobic citrate biodegradation. The modelling studies suggested that, under some conditions, chelate degradation can increase Np(IV) solubility due to carbonate complexation in closed aqueous systems. (orig.)

  10. Separation of actinides from lanthanides using acidic organophosphorus compounds: extraction chromatographic studies

    International Nuclear Information System (INIS)

    The partitioning of actinides from HLW using TBP and CMPO generates a mixture of actinides and lanthanides as one of the secondary streams. The paper discusses the results of the extraction chromatographic separation using KSM-17 and HDEHP supported on Chromosorb-102. (author)

  11. J-ACTINET activities of training and education for actinide science research

    International Nuclear Information System (INIS)

    Actinide science research is indispensable to maintain sustainable development of innovative nuclear technology, especially advanced fuels, partitioning/reprocessing, and waste management. For actinide science research, special facilities with containment and radiation shields are needed to handle actinide materials since actinide elements are γ-, α- and neutron-emitters. The number of facilities for actinide science research has been decreased, especially in universities, due to the high maintenance cost. J-ACTINET was established in 2008 to promote and facilitate actinide science research in close cooperation with the facilities and to foster many of young scientists and engineers to be actively engaged in the fields of actinide science. The research program was carried out, through which young researchers were expected to learn how to make experiments with advanced experimental tools and to broaden their horizons. The summer schools and computational science school were held to provide students, graduate students, and young researchers with the opportunities to come into contact with actinide science research. In these schools, not only the lectures, but also the practical exercises were made as essential part. The overseas dispatch program was also carried out, where graduate students and young researchers were sent to the international summer schools and conferences. (author)

  12. Invisible structures in the X-ray absorption spectra of actinides

    NARCIS (Netherlands)

    Kvashnina, Kristina O.; De Groot, Frank M F

    2014-01-01

    The X-ray absorption spectra of actinides are discussed with an emphasis on the fundamental effects that influence their spectral shape, including atomic multiplet theory, charge transfer theory and crystal field theory. Many actinide spectra consist of a single peak and it is shown that the use of

  13. Use of high gradient magnetic separation for actinide application

    International Nuclear Information System (INIS)

    Decontamination of materials such as soils or waste water that contain radioactive isotopes, heavy metals, or hazardous components is a subject of great interest. Magnetic separation is a physical separation process that segregates materials on the basis of magnetic susceptibility. Because the process relies on physical properties, separations can be achieved while producing a minimum of secondary waste. Most traditional physical separation processes effectively treat particles larger than 70 microns. In many situations, the radioactive contaminants are found concentrated in the fine particle size fraction of less than 20 microns. For effective decontamination of the fine particle size fraction most current operations resort to chemical dissolution methods for treatment. High gradient magnetic separation (HGMS) is able to effectively treat particles from 90 to ∼0.1 micron in diameter. The technology is currently used on the 60 ton per hour scale in the kaolin clay industry. When the field gradient is of sufficiently high intensity, paramagnetic particles can be physically captured and separated from extraneous nonmagnetic material. Because all actinide compounds are paramagnetic, magnetic separation of actinide containing mixtures is feasible. The advent of reliable superconducting magnets also makes magnetic separation of weakly paramagnetic species attractive. HGMS work at Los Alamos National Laboratory (LANL) is being developed for soil remediation, waste water treatment and treatment of actinide chemical processing residues. LANL and Lockheed Environmental Systems and Technologies Company (LESAT) have worked on a co-operative research and development agreement (CRADA) to develop HGMS for radioactive soil decontamination. The program is designed to transfer HGMS from the laboratory and other industries for the commercial treatment of radioactive contaminated materials. 9 refs., 2 figs., 2 tabs

  14. Final Report on Actinide Glass Scintillators for Fast Neutron Detection

    Energy Technology Data Exchange (ETDEWEB)

    Bliss, Mary; Stave, Jean A.

    2012-10-01

    This is the final report of an experimental investigation of actinide glass scintillators for fast-neutron detection. It covers work performed during FY2012. This supplements a previous report, PNNL-20854 “Initial Characterization of Thorium-loaded Glasses for Fast Neutron Detection” (October 2011). The work in FY2012 was done with funding remaining from FY2011. As noted in PNNL-20854, the glasses tested prior to July 2011 were erroneously identified as scintillators. The decision was then made to start from “scratch” with a literature survey and some test melts with a non-radioactive glass composition that could later be fabricated with select actinides, most likely thorium. The normal stand-in for thorium in radioactive waste glasses is cerium in the same oxidation state. Since cerium in the 3+ state is used as the light emitter in many scintillating glasses, the next most common substitute was used: hafnium. Three hafnium glasses were melted. Two melts were colored amber and a third was clear. It barely scintillated when exposed to alpha particles. The uses and applications for a scintillating fast neutron detector are important enough that the search for such a material should not be totally abandoned. This current effort focused on actinides that have very high neutron capture energy releases but low neutron capture cross sections. This results in very long counting times and poor signal to noise when working with sealed sources. These materials are best for high flux applications and access to neutron generators or reactors would enable better test scenarios. The total energy of the neutron capture reaction is not the only factor to focus on in isotope selection. Many neutron capture reactions result in energetic gamma rays that require large volumes or high densities to detect. If the scintillator is to separate neutrons from gamma rays, the capture reactions should produce heavy particles and few gamma rays. This would improve the detection of a

  15. Review of alpha-particle spectrometric measurements of actinides

    International Nuclear Information System (INIS)

    At present the silicon surface-barrier detector is the most used α-particle detector mainly due to its high energy resolution, excellent stability, low background and low cost. In this presentation various parameters of importance for α-particle spectrometry are discussed, i.e. energy resolution and interval selection, energy calibration, background and peak tailing. Examples of α-particle spectra recorded from various actinides (Th, U, Np, Pu, Am, and Cm) separated from environmental samples are shown, and the choice of yield determinants is discussed for each case. (author)

  16. Hydrometallurgical minor actinide separation in hollow fiber modules

    International Nuclear Information System (INIS)

    Hollow fiber modules (HFM) were used as phase contacting devices for hydrometallurgical minor actinide separation in the Partitioning and Transmutation context. Two single-HFM setups, one using commercially available HFM, the other one using miniature HFM, have been developed and manufactured. Several very successful DIAMEX and SANEX once-through tests were performed. The major advantage of the new miniature HFM is their size drastically reducing chemicals consumption: only several 10 mL of feed phases are required for a test. (authors)

  17. Neutron absorption spectroscopy for identification of light elements in actinides

    International Nuclear Information System (INIS)

    We are developing cryogenic high-energy resolution fast-neutron spectrometers using superconducting transition-edge sensors (TES) for nuclear science and non-proliferation applications. Fast neutrons are absorbed in 94% enriched 6LiF single crystals with volumes of ∼1 cm3 in an exothermic 6Li(n,α)3H capture reaction. The neutron energy is measured from the subsequent temperature rise with a Mo/Cu multilayer TES. Fast-neutron spectra from a 252Cf source show an energy resolution of 55 kev. Here, we discuss the instrument performance, with emphasis on the identification of light elements in actinide matrices

  18. Voluntary activities on actinides by the public in Peninsula Shimokita

    International Nuclear Information System (INIS)

    Peninsula Shimokita is known as a Nuclear Peninsula. A technical term actinides', however, is not used among the public here. It is not only used, but also is not probably known among them, although an investigation for the terminology and vocabulary on the nuclear science and technology among the public in this district has not ever performed. The terms in use here widely are uranium (-235, -238), plutonium (-239), and trans-uranium elements for what are heavier than the uranium. The present paper will report on voluntary activities by the public in the Penin. Shimokita performed after the neutron criticality accident at JCO Tokai of a company for nuclear fuel conversion. (author)

  19. Fission of actinides using a table-top laser

    CERN Document Server

    Schwoerer, H; Sauerbrey, R; Galy, J; Magill, J; Rondinella, V; Schenkel, R; Butz, T

    2003-01-01

    Powerful table-top lasers are now available in the laboratory and can be used to induce nuclear reactions. We report the first demonstration of nuclear fission using a high repetition rate table-top laser with intensities of 10 sup 2 sup 0 W/cm sup 2. Actinide photo-fission has been achieved in both sup 2 sup 3 sup 8 U and sup 2 sup 3 sup 2 Th from the high-energy Bremsstrahlung radiation produced by laser acceleration of electrons. The fission products were identified by time-resolved gamma-spectroscopy. (authors)

  20. Detection of Actinides via Nuclear Isomer De-Excitation

    Energy Technology Data Exchange (ETDEWEB)

    Francy, Christopher J. [Oregon State Univ., Corvallis, OR (United States)

    2009-07-01

    This dissertation discusses a data collection experiment within the Actinide Isomer Identification project (AID). The AID project is the investigation of an active interrogation technique that utilizes nuclear isomer production, with the goal of assisting in the interdiction of illicit nuclear materials. In an attempt to find and characterize isomers belonging to 235U and its fission fragments, a 232Th target was bombarded with a monoenergetic 6Li ion beam, operating at 45 MeV.

  1. Electron-phonon coupling of the actinide metals

    DEFF Research Database (Denmark)

    Skriver, H. L.; Mertig, I.

    1985-01-01

    -phonon parameter λ is found to attain its maximum value in Ac, and they predict a transition temperature of 9K for this metal. In the light actinides Th through Pu, λ is found to be of order 0.4 and within a factor of 2 of experiments which is also the accuracy found in studies of the transition metals...... be related to the changeover from an s-to- d to an s-to-f electronic transition and a related change in the topology of the Fermi surface...

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

    International Nuclear Information System (INIS)

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

  3. Neutronics design study on a minor actinide burner for transmuting spent fuel

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hang Bok

    1998-08-01

    A liquid metal reactor was designed for the primary purpose of burning the minor actinide waste from commercial light water reactors. The design was constrained to maintain acceptable safety performance as measured by the burnup reactivity swing, the doppler coefficient, and the sodium void worth. Sensitivity studies were performed for homogeneous and decoupled core designs, and a minor actinide burner design was determined to maximize actinide consumption and satisfy safety constraints. One of the principal innovations was the use of two core regions, with a fissile plutonium outer core and an inner core consisting only of minor actinides. The physics studies performed here indicate that a 1200 MWth core is able to transmute the annual minor actinide inventory of about 16 LWRs and still exhibit reasonable safety characteristics. (author). 34 refs., 22 tabs., 14 figs.

  4. Selective extraction of trivalent actinides from lanthanides with dithiophosphinic acids and tributylphosphate

    Energy Technology Data Exchange (ETDEWEB)

    Jarvinen, G.; Barrans, R.; Schroeder, N.; Wade, K.; Jones, M.; Smith, B.F. [Los Alamos National Lab., NM (United States); Mills, J.; Howard, G. [Texas Tech Univ., Lubbock, TX (United States); Freiser, H.; Muralidharan, S. [Arizona Univ., Tucson, AZ (United States)

    1995-01-01

    A variety of chemical systems have been developed to separate trivalent actinides from lanthanides based on the slightly stronger complexation of the trivalent actinides with ligands that contain soft donor atoms. The greater stability of the actinide complexes in these systems has often been attributed to a slightly greater covalent bonding component for the actinide ions relative to the lanthanide ions. The authors have investigated several synergistic extraction systems that use ligands with a combination of oxygen and sulfur donor atoms that achieve a good group separation of the trivalent actinides and lanthanides. For example, the combination of dicyclohexyldithiophosphinic acid and tributylphosphate has shown separation factors of up to 800 for americium over europium in a single extraction stage. Such systems could find application in advanced partitioning schemes for nuclear waste.

  5. Measurement of standard potentials of actinides (U,Np,Pu,Am) in LiCl-KCl eutectic salt and separation of actinides from rare earths by electrorefining

    International Nuclear Information System (INIS)

    Pyrochemical separation of actinides from rare earths in LiCl-KCl eutectic-liquid metal systems has been studied. The electromotive forces of galvanic cells of the form, Ag vertical stroke Ag(I), LiCl-KCl parallel actinide(III), LiCl-KCl vertical stroke actinide, were measured and standard potentials were determined for uranium, neptunium and plutonium to be -1.283 V, -1.484 V and -1.593 V (at 450 C vs. Ag/AgCl (1wt%-AgCl)), respectively. A typical cyclic voltammogram of americium chloride has two cathodic peaks, which suggests reduction Am(III)→Am(II) occurs followed by reduction of Am(II) to americium metal. Standard potential of Am(II)/Am(0) was estimated to be -1.642 V. Electrorefining experiments to separate actinides (U, Np, Pu and Am) from rare earths (Y, La, Ce, Nd and Gd) in LiCl-KCl eutectic salt were carried out. It was shown that the actinide metals were recovered on the cathodes and that americium was the most difficult to separate from rare earths. The actinide separation will be achieved by means of the combination of electrorefining with multistage extraction. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

    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/sub 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/sub 5//HF solution or Pu(VII) in Li/sub 5/PuO/sub 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.

  7. APPLICATION OF ABSORPTION SPECTROSCOPY TO ACTINIDE PROCESS ANALYSIS AND MONITORING

    Energy Technology Data Exchange (ETDEWEB)

    Lascola, R.; Sharma, V.

    2010-06-03

    The characteristic strong colors of aqueous actinide solutions form the basis of analytical techniques for actinides based on absorption spectroscopy. Colorimetric measurements of samples from processing activities have been used for at least half a century. This seemingly mature technology has been recently revitalized by developments in chemometric data analysis. Where reliable measurements could formerly only be obtained under well-defined conditions, modern methods are robust with respect to variations in acidity, concentration of complexants and spectral interferents, and temperature. This paper describes two examples of the use of process absorption spectroscopy for Pu analysis at the Savannah River Site, in Aiken, SC. In one example, custom optical filters allow accurate colorimetric measurements of Pu in a stream with rapid nitric acid variation. The second example demonstrates simultaneous measurement of Pu and U by chemometric treatment of absorption spectra. The paper concludes with a description of the use of these analyzers to supplement existing technologies in nuclear materials monitoring in processing, reprocessing, and storage facilities.

  8. Tomography of actinides by photofission in bulky radioactive waste packages

    International Nuclear Information System (INIS)

    Quantifying actinides using non-destructive methods, in radioactive waste packages, is a great stake to turn packages towards appropriate storage facility. But the nature of radiations emitted by actinides (alpha radiations) makes the detection of those very difficult for large volume packages characterization. Indeed, the emitted radiation is too weak, either to be detected by emission tomography or to reach required sensitivities. Therefore, it is necessary to turn to an external probing source. Tomography based on detection of delayed neutrons induced by photofission, allows to probe bulky packages. We demonstrate the suitability of this method to an industrial stage. Firstly, we determine and qualify projection matrix which connects measures at reconstructed activity of tomographic picture. Thus, during measurements on a model and a real package, we carry out convincing tomographic reconstructions with real acquisition conditions. More, we prove that it is possible to take all disruptive chemical element into account, for tomographic reconstructions, in order to obtain the best image of activity. So, we propose a finalised tomographic device, integrating a shielding cell, and checking all the activity and distribution activity criterions fixed for acceptance of radioactive waste packages in superficial storage facility. (author)

  9. Electrochemical reduction of actinides oxides in molten salts

    International Nuclear Information System (INIS)

    Reactive metals are currently produced from their oxide by multiple steps reduction techniques. A one step route from the oxide to the metal has been suggested for metallic titanium production by electrolysis in high temperature molten chloride salts. In the so-called FFC process, titanium oxide is electrochemically reduced at the cathode, generating O2- ions, which are converted on a graphite anode into carbon oxide or dioxide. After this process, the spent salt can in principle be reused for several batches which is particularly attractive for a nuclear application in terms of waste minimization. In this work, the electrochemical reduction process of cerium oxide (IV) is studied in CaCl2 and CaCl2-KCl melts to understand the oxide reduction mechanism. Cerium is used as a chemical analogue of actinides. Electrolysis on 10 grams of cerium oxide are made to find optimal conditions for the conversion of actinides oxides into metals. The scale-up to hundred grams of oxide is also discussed. (author)

  10. Energy-Dependent Fission Q Values Generalized for All Actinides

    Energy Technology Data Exchange (ETDEWEB)

    Vogt, R

    2008-09-25

    We generalize Madland's parameterization of the energy release in fission to obtain the dependence of the fission Q values on incident neutron energy, E{sub n}, for all major and minor actinides. These Q(E{sub n}) parameterizations are included in the ENDL2008 release. This paper describes calculations of energy-dependent fission Q values based on parameterizations of the prompt energy release in fission [1], developed by Madland [1] to describe the prompt energy release in neutron-induced fission of {sup 235}U, {sup 238}U, and {sup 239}Pu. The energy release is then related to the energy deposited during fission so that experimentally measurable quantities can be used to obtain the Q values. A discussion of these specific parameterizations and their implementation in the processing code for Monte Carlo neutron transport, MCFGEN, [2] is described in Ref. [3]. We extend this model to describe Q(E) for all actinides, major and minor, in the Evaluated Nuclear Data Library (ENDL) 2008 release, ENDL2008.

  11. Minor actinides transmutation strategies in sodium fast reactors

    International Nuclear Information System (INIS)

    In minor actinides transmutation strategies for fast spectrum reactors, different possibilities regarding the core loading are considered. We study both homogeneous patterns (HOM) with various minor actinides (MA) content values and heterogeneous schemes (HET) with higher percentages of MA (Np, Am and Cm) at the periphery of reactor. We analyze the capability of transmutation of each design and the reactivity coefficients such as the Doppler constant, void worth and the fraction of delayed neutrons. The EVOLCODE2 code is the computational tool used in this study. It is based on MCNPX and ORIGEN/ACAB codes and allows carrying out burn-up calculations to get the isotopic evolution of fuel composition. Among the three strategies studied (HOM 2.5 %, HOM 4% and HET 20 %) for a possible design of a Sodium Cooled Fast Breeder Reactor, the one with better transmutation results is the HOM 4%, which shows higher absolute and relative values (12 Kg-MA/TWe, 29% respectively). Concerning transmutation in blankets with 20% MA content, results show a very little or no transmutation values when considering Np, Am and Cm together, though a positive small value for Np and Am is obtained

  12. Removal of actinides from dilute waste waters using polymer filtration

    International Nuclear Information System (INIS)

    More stringent US Department of Energy discharge regulations for waste waters containing radionuclides (30 pCi/L total alpha) require the development of new processes to meet the new discharge limits for actinide metal ions, particularly americium and plutonium, while minimizing waste. We have been investigating a new technology, polymer filtration, that has the potential for effectively meeting these new limits. Traditional technology uses basic iron precipitation which produces large amounts of waste sludge. The new technology is based on using water-soluble chelating polymers with ultrafiltration for physical separation. The actinide metal ions are selectively bound to the polymer and can not pass through the membrane. Small molecules and nonbinding metals pass through the membrane. Advantages of polymer filtration technology compared to ion, exchange include rapid kinetics because the binding is occurring in a homogenous solution and no mechanical strength requirement on the polymer. We will present our results on the systematic development of a new class of water-soluble chelating polymers and their binding ability from dilute acid to near neutral waters

  13. Effects of actinide burning on waste disposal at Yucca Mountain

    International Nuclear Information System (INIS)

    Release rates of 15 radionuclides from waste packages expected to result from partitioning and transmutation of Light-Water Reactor (LWR) and Actinide-Burning Liquid-Metal Reactor (ALMR) spent fuel are calculated and compared to release rates from standard LWR spent fuel packages. The release rates are input to a model for radionuclide transport from the proposed geologic repository at Yucca Mountain to the water table. Discharge rates at the water table are calculated and used in a model for transport to the accessible environment, defined to be five kilometers from the repository edge. Concentrations and dose rates at the accessible environment from spent fuel and wastes from reprocessing, with partitioning and transmutation, are calculated. Partitioning and transmutation of LWR and ALMR spent fuel reduces the inventories of uranium, neptunium, plutonium, americium and curium in the high-level waste by factors of 40 to 500. However, because release rates of all of the actinides except curium are limited by solubility and are independent of package inventory, they are not reduced correspondingly. Only for curium is the repository release rate much lower for reprocessing wastes

  14. Actinides transmutation - a comparison of results for PWR benchmark

    Energy Technology Data Exchange (ETDEWEB)

    Claro, Luiz H. [Instituto de Estudos Avancados (IEAv/CTA), Sao Jose dos Campos, SP (Brazil)], e-mail: luizhenu@ieav.cta.br

    2009-07-01

    The physical aspects involved in the Partitioning and Transmutation (P and T) of minor actinides (MA) and fission products (FP) generated by reactors PWR are of great interest in the nuclear industry. Besides these the reduction in the storage of radioactive wastes are related with the acceptability of the nuclear electric power. From the several concepts for partitioning and transmutation suggested in literature, one of them involves PWR reactors to burn the fuel containing plutonium and minor actinides reprocessed of UO{sub 2} used in previous stages. In this work are presented the results of the calculations of a benchmark in P and T carried with WIMSD5B program using its new cross sections library generated from the ENDF-B-VII and the comparison with the results published in literature by other calculations. For comparison, was used the benchmark transmutation concept based in a typical PWR cell and the analyzed results were the k{infinity} and the atomic density of the isotopes Np-239, Pu-241, Pu-242 and Am-242m, as function of burnup considering discharge of 50 GWd/tHM. (author)

  15. Actinide production from xenon bombardments of curium-248

    International Nuclear Information System (INIS)

    Production cross sections for many actinide nuclides formed in the reaction of 129Xe and 132Xe with 248Cm at bombarding energies slightly above the coulomb barrier were determined using radiochemical techniques to isolate these products. These results are compared with cross sections from a 136Xe + 248Cm reaction at a similar energy. When compared to the reaction with 136Xe, the maxima in the production cross section distributions from the more neutron deficient projectiles are shifted to smaller mass numbers, and the total cross section increases for the production of elements with atomic numbers greater than that of the target, and decreases for lighter elements. These results can be explained by use of a potential energy surface (PES) which illustrates the effect of the available energy on the transfer of nucleons and describes the evolution of the di-nuclear complex, an essential feature of deep-inelastic reactions (DIR), during the interaction. The other principal reaction mechanism is the quasi-elastic transfer (QE). Analysis of data from a similar set of reactions, 129Xe, 132Xe, and 136Xe with 197Au, aids in explaining the features of the Xe + Cm product distributions, which are additionally affected by the depletion of actinide product yields due to deexcitation by fission. The PES is shown to be a useful tool to predict the general features of product distributions from heavy ion reactions

  16. Diamond for Actinide Traces Detection and Spectrometry in Liquids

    International Nuclear Information System (INIS)

    We describe here a new approach for the detection and identification of actinides (Am, Pu, Cm etc) at very low activity levels in aqueous solution. The measurement consists at first in the electro-precipitation of the actinides ions as insoluble hydroxides directly onto a boron doped nanocrystalline diamond (BNCD) electrode deposited on an α-particle detector (Si or Si-PIN diode), followed by α-particles detection using front-end nuclear electronics. After α-particles counting, spectrometry, the detector can be easily decontaminated using anodization in aqueous solution to be able to be reused at once. The detection limit of the described prototype system can be estimated as low as a few mBq=L (for one day counting) to several mBq=L for 5 h counting and currently achieved energy resolution amounts to ΔEFW HM/Eα = 2.3% for pulse height spectra of 5.486 MeV α-particles emitted by 241Am, measured directly in water. (authors)

  17. Physical chemistry and modelling of the sintering of actinide oxides

    International Nuclear Information System (INIS)

    This report gives a synthesis of the work I have carried out or to which I have numerically contributed to from 1996 up to 2012 in the Department of Plutonium Uranium and minor Actinides in Cadarache CEA Center. Their main goal is the study and the modeling of the sintering process of nuclear fuels which is the unifying thread of this document. Both in order to take into account the physical and chemical features of the actinide bearing oxide material and in order to combine the different transport phenomena leading to sintering, a sub-granular scale model is under development. Extension to a varying chemical composition as well as exchanges with the gaseous phase are foreseen. A simulation on a larger scale (pellet scale) is ongoing in the framework of a PhD thesis. Validation means have been tested with (U,Pu)O2 material on the scale of the pellet (Small Angle Neutron Diffusion), on the scale of powder granules (X-Ray High Resolution Micro-Tomography) and with CeO2 at the 'Institut de Chimie Separative' in Marcoule on a single crystal scale (Environmental Scanning Electron Microscope). The required microstructure homogeneity for nuclear fuels has led to a campaign of experimental studies about the role of Cr2O3 as a sintering aid. Whole of these studies improve our understanding of fuel sintering and hence leads to an improved mastering of this process. (author)

  18. The significance of distribution coefficients in the remobilisation of actinides from intertidal sediments of the Ravenglass Estuary

    International Nuclear Information System (INIS)

    Distribution coefficients (Ksub(d)) were determined for desorption of actinides from Ravenglass Estuary intertidal sediment into 'inactive' seawater from the North Sea. Values of 1.1 x 106 for 239+240Pu and 2.0 x 106 from 241Am were obtained. Further experiments indicated the desorption-sorption equilibrium reaction for plutonium is an oxidation-reduction process, the sediment itself able to reduce Pu V+VI to Pu III+IV, whereas for americium the formation of a soluble carbonate complex is thought to occur. Using seawater diluted with river water, Ksub(d) values were found to decrease by approx. two orders of magnitude at low values of salinity, characteristic of low tide conditions and in the upper estuary. Tidal balance experiments indicated the Ravenglass Estuary currently acts as a radionuclide source to the Irish Sea, actinides being lost from the estuary in suspended sediment. Distribution coefficients for 239+240Pu measured during three tidal cycles were approx. = 106 at low water but decreasing rapidly on the flood. The effect was more pronounced in calm conditions and did not follow the relationship between desorption ksub(d) and salinity observed in the laboratory experiments. (author)

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

    International Nuclear Information System (INIS)

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

  20. Phytosiderophore Effects on Subsurface Actinide Contaminants: Potential for Phytostabilization and Phytoextraction

    Energy Technology Data Exchange (ETDEWEB)

    Ruggiero, Christy

    2005-06-01

    This project seeks to understand the influence of phytosiderophore-producing plants (grasses, including crops such as wheat and barley) on the biogeochemistry of actinide and other metal contaminants in the subsurface environment, and to determine the potential of phytosiderophore-producing plants for phytostabilization and phytoextraction of actinides and some metal soil contaminants. Phytosiderophores are secreted by graminaceous plants such as barley and wheat for the solubilization, mobilization and uptake of Fe and other essential nutrients from soils. The ability for these phytosiderophores to chelate and absorb actinides using the same uptake system as for Fe is being investigated though characterization of actinide-phytosiderophore complexes (independently of plants), and characterization of plant uptake of such complexes. We may also show possible harm caused by these plants through increased chelation of actinides that increase in actinide mobilization & migration in the subsurface environment. This information can then be directly applied by either removal of harmful plants, or can be used to develop plant-based soil stabilization/remediation technologies. Such technologies could be the low-cost, low risk solution to many DOE actinide contamination problems.

  1. Design, synthesis, and evaluation of polyhydroxamate chelators for selective complexation of actinides

    International Nuclear Information System (INIS)

    Specific chelating polymers targeted for actinides have much relevance to problems involving remediation of nuclear waste. Goal is to develop polymer supported, ion specific extraction systems for removing actinides and other hazardous metal ions from wastewaters. This is part of an effort to develop chelators for removing actinide ions such as Pu from soils and waste streams. Selected ligands are being attached to polymeric backbones to create novel chelating polymers. These polymers and other water soluble and insoluble polymers have been synthesized and are being evaluated for ability to selectively remove target metal ions from process waste streams

  2. Conjugates of Actinide Chelator-Magnetic Nanoparticles for Used Fuel Separation Technology

    Energy Technology Data Exchange (ETDEWEB)

    Qiang, You; Paszczynski, Andrzej; Rao, Linfeng

    2011-10-30

    The actinide separation method using magnetic nanoparticles (MNPs) functionalized with actinide specific chelators utilizes the separation capability of ligand and the ease of magnetic separation. This separation method eliminated the need of large quantity organic solutions used in the liquid-liquid extraction process. The MNPs could also be recycled for repeated separation, thus this separation method greatly reduces the generation of secondary waste compared to traditional liquid extraction technology. The high diffusivity of MNPs and the large surface area also facilitate high efficiency of actinide sorption by the ligands. This method could help in solving the nuclear waste remediation problem.

  3. Operating procedures for the manufacture of radioactive SYNROC in the actinide laboratory

    International Nuclear Information System (INIS)

    The purpose of this manual is to acquaint the operator with the procedures required to manufacture SYNROC-containing radioactive materials in the SYNROC actinide laboratory, Lucas Heights Research Laboratories. The actinide-doped SYNROC production facility is a series of four interconnected glove boxes and one free-standing glove box. The samples of radioactive SYNROC produced in the actinide laboratory are used to carry out physical testing of the product at various laboratories on site, e.g. leach testing, auto-radiographic examination, electron-microscopc examination, atomic absorption spectrophotometry and analysis

  4. Actinides and rare earths complexation with adenosine phosphate nucleotides

    International Nuclear Information System (INIS)

    Organophosphorus compounds are important molecules in both nuclear industry and living systems fields. Indeed, several extractants of organophosphorus compounds (such as TBP, HDEHP) are used in the nuclear fuel cycle reprocessing and in the biological field. For instance, the nucleotides are organophosphates which play a very important role in various metabolic processes. Although the literature on the interactions of actinides with inorganic phosphate is abundant, published studies with organophosphate compounds are generally limited to macroscopic and / or physiological approaches. The objective of this thesis is to study the structure of several organophosphorus compounds with actinides to reach a better understanding and develop new specific buildings blocks. The family of the chosen molecules for this procedure consists of three adenine nucleotides mono, bi and triphosphate (AMP, adenosine monophosphate - ADP, adenosine diphosphate - ATP, adenosine triphosphate) and an amino-alkylphosphate (AEP O-phosphoryl-ethanolamine). Complexes synthesis was conducted in aqueous and weakly acidic medium (2.8-4) for several lanthanides (III) (Lu, Yb, Eu) and actinides (U (VI), Th (IV) and Am (III)). Several analytical and spectroscopic techniques have been used to describe the organization of the synthesized complexes: spectrometric analysis performed by FTIR and NMR were used to identify the functional groups involved in the complexation, analysis by ESI-MS and pH-metric titration were used to determine the solution speciation and EXAFS analyzes were performed on Mars beamline of the SOLEIL synchrotron, have described the local cation environment, for both solution and solid compounds. Some theoretical approaches of DFT were conducted to identify stable structures in purpose of completing the experimental studies. All solid complexes (AMP, ADP, ATP and AEP) have polynuclear structures, while soluble ATP complexes are mononuclear. For all synthesized complexes, it has been

  5. Scissors strength in the quasi-continuum of actinides

    Directory of Open Access Journals (Sweden)

    Guttormsen M.

    2014-03-01

    Full Text Available The M1-scissors resonance has been measured for the first time in the quasi-continuum of actinides. The strength and position of the resonances in 231,232,233Th were determined by particle-γ coincidences using deuteron induced reactions on a 232Th target. The residual nuclei show a strong integrated strength of BM1 = 9 − 11 µn2 in the Eγ = 1.0 − 3.5 MeV region. The presence of the scissors resonance modifies significantly the (n,γ cross section, which has impact on fuel-cycle simulations of fast nuclear reactors and nucleosynthesis in explosive stellar environments.

  6. Instrumentation for high-efficiency, high-sensitivity actinide analysis

    International Nuclear Information System (INIS)

    This is the final report of a 3-year project. We have developed a high-efficiency thermal ionization source that provides one to two orders of magnitude improvement in sample utilization efficiency in comparison with the traditional filament-type ion source currently used in thermal ionization mass spectrometry. This improved sample utilization efficiency results in a proportional increase in sample throughput and proportional decrease in analysis time. Coupling this source with a quadrupole mass spectrometer results in an instrument system for high-efficiency actinide analysis and other applications. In addition to its high efficiency, the sample used in this source can be much smaller than that in previous tube-type sources. The compact structure of the cavity makes it more applicable to any type of mass spectrometer and the whole instrument is small and transportable

  7. Two new animal models for actinide toxicity studies

    International Nuclear Information System (INIS)

    Two small rodent species, the grasshopper mouse (Onychomys leucogaster) and the deer mouse (Peromyscus maniculatus) have tenacious retention in the liver and skeleton of plutonium and americium. The retention following intraperitoneal injection of Pu and Am in citrate solution ranged from 20 to 47% (liver) and 19 to 42% (skeleton), relatively independent of post-injection times, varying from 30 to 125 days. Based on observations extended to 125 days post-injection, the biological half-times appeared to be long. Both of these rodents are relatively long-lived (median lifespans of approximately 1400 days), breed well in captivity, and adapt suitably to laboratory conditions. It is suggested that these two species of mice, in which plutonium is partitioned between the skeleton and liver in a manner similar to that of man, may be useful animal models for actinide toxicity studies

  8. Fabrication of indigenous computer controlled photoacoustic spectrometer for actinide spectroscopy

    International Nuclear Information System (INIS)

    The photoacoustic spectroscopy (PAS) monitoring the non-radiative de-excitation process is a powerful tool for investigating the absorption spectra of almost any type of samples like opaque solids, turbid solutions etc. Actinide compounds due to high probability of non-radiative relaxation process are good candidates for PAS investigations and also without any need for good optical quality crystals of these compounds. In addition, this technique is extremely useful for determination of thermal properties like thermal conductivity, diffusivity and related properties like phase transitions, thickness of thin film etc. In the present paper details of fabrication of indigenous PAS unit using low cost easily available components and interfacing this unit to a personal computer are given

  9. Flammability Analysis For Actinide Oxides Packaged In 9975 Shipping Containers

    Energy Technology Data Exchange (ETDEWEB)

    Laurinat, James E.; Askew, Neal M.; Hensel, Steve J.

    2013-03-21

    Packaging options are evaluated for compliance with safety requirements for shipment of mixed actinide oxides packaged in a 9975 Primary Containment Vessel (PCV). Radiolytic gas generation rates, PCV internal gas pressures, and shipping windows (times to reach unacceptable gas compositions or pressures after closure of the PCV) are calculated for shipment of a 9975 PCV containing a plastic bottle filled with plutonium and uranium oxides with a selected isotopic composition. G-values for radiolytic hydrogen generation from adsorbed moisture are estimated from the results of gas generation tests for plutonium oxide and uranium oxide doped with curium-244. The radiolytic generation of hydrogen from the plastic bottle is calculated using a geometric model for alpha particle deposition in the bottle wall. The temperature of the PCV during shipment is estimated from the results of finite element heat transfer analyses.

  10. Chemistry of tetravalent actinides phosphates. The thorium phosphate-diphosphate as immobilisation matrix of actinides; Chimie des phosphates d'actinides tetravalents. Le phosphate-diphosphate de thorium en tant que matrice d'imobilisation des actinides

    Energy Technology Data Exchange (ETDEWEB)

    Dacheux, N

    2002-07-01

    The author presents in this document its scientific works from 1992 to 2001, in order to obtain the enabling to manage scientific and chemical researches at the university Paris Sud Orsay. The first part gives an abstract of the thesis on the characterizations, lixiviation and synthesis of uranium and thorium based phosphate matrix in the framework of the search for a ceramic material usable in the radioactive waste storage. The second part presents briefly the researches realized at the CEA, devoted to a reliable, independent and accurate measure of some isotopes activity. The last part presents the abstracts of researches activities from 1996 to 2001 on the tetravalent actinides phosphates chemistry, the sintering of PDT and solid solutions of PDTU and the kinetic and thermodynamical studies of the PDT dissolution. Many references and some publication in full text are provided. (A.L.B.)

  11. Decorporation of actinides: a review of recent research

    International Nuclear Information System (INIS)

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

  12. Actinide-only burnup credit for spent fuel transport

    International Nuclear Information System (INIS)

    A conservative methodology is described that would allow taking credit for burn up in the criticality safety analysis of spent nuclear fuel packages. Requirements for its implementation include isotopic and criticality validation, generation of package loading criteria using limiting parameters, and assembly burn up verification by measurement. The method allows credit for the changes in the 234U, 235U, 236U, 238U, 238Pu, 239Pu, 240Pu, 241Pu, 242Pu, and 241Am concentrations with burnup. No credit for fission product neutron absorbers is taken. Analyses are included regarding the methodology's financial benefits and conservative margin. It is estimated that the proposed actinide-only burnup credit methodology would save 20% of the transport costs. Nevertheless, the methodology includes a substantial margin. Conservatism due to the isotopic correction factors, limiting modelling parameters, limiting axial profiles and exclusion of the fission products ranges from 10 to 25% k. (author)

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

    CERN Document Server

    Sors, M

    1999-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Oh, George N. [Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, IN 46556 (United States); Burns, Peter C., E-mail: pburns@nd.edu [Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, IN 46556 (United States); Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 (United States)

    2014-07-01

    The reaction of UO{sub 3} and H{sub 3}PO{sub 3} at 100 °C and subsequent reaction with dimethylformamide (DMF) produces crystals of the compound (NH{sub 2}(CH{sub 3}){sub 2})[UO{sub 2}(HPO{sub 2}OH)(HPO{sub 3})]. This compound crystallizes in space group P2{sub 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{sub 2}OH){sub 4} (An=U, Th) and of the mixed acid phosphite–phosphite U(HPO{sub 3})(HPO{sub 2}OH){sub 2}(H{sub 2}O)·2(H{sub 2}O). α- and β-An(HPO{sub 2}OH){sub 4} crystallize in space groups C2/c and P2{sub 1}/n, respectively, and comprise a three-dimensional network of An{sup 4+} cations in square antiprismatic coordination corner-sharing with protonated phosphite units, whereas U(HPO{sub 3})(HPO{sub 2}OH){sub 2}(H{sub 2}O){sub 2}·(H{sub 2}O) crystallizes in a layered structure in space group Pbca that is composed of An{sup 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{sub 3} and H{sub 3}PO{sub 3} at 100 °C and subsequent reaction with DMF produces crystals of (NH{sub 2}(CH{sub 3}){sub 2})[UO{sub 2}(HPO{sub 2}OH)(HPO{sub 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{sub 2}OH){sub 4} (An=U, Th), with a three-dimensional network structure, and the mixed acid phosphite

  15. EXAFS studies of sodium silicate glasses containing dissolved actinides

    International Nuclear Information System (INIS)

    Sodium silicate glasses containing dissolved Th, U, Np, and Pu have been studied using the EXAFS technique. Th4+, U4+, Np4+, and Pu4+ ions in the silicate glasses are 8-fold coordinated to oxygen neighbors. The higher valent U6+ and Np5+ ions have complex local symmetries. The U6+ ions appear in a uranyl configuration with 2 oxygen atoms at 1.85A and 4 at 2.25A from the U ion. The Np5+ local symmetry is more complex and difficult to determine uniquely. The U6+ glasses show substantial clustering of the uranium atoms. A structural model, with nearly planar uranyl sheets sandwiched between alkali and silica layers, is used to explain the U6+ EXAFS data. This model allows us to understand why U6+ ions are much more soluble in the glasses than the actinide 4+ ions. 4 references, 2 figures

  16. The electronic g matrix of some actinide complexes

    International Nuclear Information System (INIS)

    Complete text of publication follows: The molecular g-factors are crucial parameters in Electron Paramagnetic Resonance (EPR) spectroscopy. They parametrize the Zeeman effect that involves the interaction of a spin magnetic moment with a magnetic field. Before the 90's, g-factors were mostly calculated by semi-empirical methods while in the last decade, ab initio techniques have been developed based on wave functions or density functional theories either using a sum over states (SOS) expansion or using response theory [1]. We have recently proposed an alternative method based on wave function theory including spin-orbit effects by the SO-RASSI method [2]. This method has been applied with success to small molecules containing atoms until the third series of the transition metals and to a mixed-valence bimetallic complex[3] and in this work, it is applied to actinide complexes with a 5f1 configuration. To our knowledge, only few attempts have been made to calculate g-factors of actinide complexes from first principles [4, 5]. Relativistic effects in actinide complexes are important, so the deviation of g-factors from the value of the free electron is large and can even become negative. Most of the experiments measuring magnetic properties of actinide complexes date from the sixties. EPR and magnetic susceptibilities give the absolute values of the g-factors while experiment using circularly polarized light provide the sign of the product of the three factors. Magnetic properties of these compounds are easily understood using ligand field theory models. In the first part of this presentation, we will discuss the arbitrary character of the g-matrix and specially of the effect of phase factors and of the choice of the spin quantification axis and we will show that only the G tensor gg* has a physical significance. In the second part, equilibrium distances, excitation energies and g-factors of the AnXq-6 series with An = Pa,U,Np and X = F,Cl,Br are calculated using the

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

    CERN Multimedia

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

  18. Actinides in Solution: Disproportionation, Strong Correlations, and Emergence

    Science.gov (United States)

    Marston, Brad; Horowitz, Steven

    2010-03-01

    Plutonium in acid solutions can be found in oxidation states III through VI. There is a striking near perfect degeneracy of the reduction-oxidation (redox) potentials, each being about 1 volt. Neptunium is the only other element that approaches this degree of degeneracy. One consequence of the redox degeneracy is a marked tendency of plutonium ions to disproportionate; up to four different oxidation states can coexist simultaneously in the same solution, greatly complicating the environmental chemistry of the element. While the degeneracy could simply be a coincidence, it could also be the manifestation of a higher-level organizing principle at work. Other systems that exhibit disproportionation raise the possibility of an emergent negative-U attractive interaction. The hypothesis is tested by combining first-principles relativistic density-functional calculations using the Amsterdam Density Functional (ADF) package with exact diagonalizations of Hubbard-like models of the strong correlations between the actinide 5f electrons.

  19. Actinide sequestration using self-assembled monolayers on mesoporous supports.

    Science.gov (United States)

    Fryxell, Glen E; Lin, Yuehe; Fiskum, Sandy; Birnbaum, Jerome C; Wu, Hong; Kemner, Ken; Kelly, Shelley

    2005-03-01

    Surfactant templated synthesis of mesoporous ceramics provides a versatile foundation upon which to create high efficiency environmental sorbents. These nanoporous ceramic oxides condense a huge amount of surface area into a very small volume. The ceramic oxide interface is receptive to surface functionalization through molecular self-assembly. The marriage of mesoporous ceramics with self-assembled monolayer chemistry creates a powerful new class of environmental sorbent materials called self-assembled monolayers on mesoporous supports (SAMMS). These SAMMS materials are highly efficient sorbents whose interfacial chemistry can be fine-tuned to selectively sequester a specific target species, such as heavy metals, tetrahedral oxometalate anions, and radionuclides. Details addressing the design, synthesis, and characterization of SAMMS materials specifically designed to sequester actinides, of central importance to the environmental cleanup necessary after 40 years of weapons-grade plutonium production, as well as evaluation of their binding affinities and kinetics are presented. PMID:15787373

  20. Effects of actinide burning on waste disposal at Yucca Mountain

    International Nuclear Information System (INIS)

    Partitioning the actinides in spent fuel and transmuting them in actinide-burning liquid-metal reactors (ALMRs) is a potential method of reducing public risks from the geologic disposal of nuclear waste. In this paper, the authors present a comparison of radionuclide releases from burial at Yucca Mountain of spent fuel and of ALMR wastes. Two waste disposal schemes are considered. In each, the heat generation of the wastes at emplacement is 9.88 x 107 W, the maximum for the repository. In the first scheme, the repository contains 86,700 tonnes of initial heavy metal (IHM) of light water reactor (LWR) spent fuel. In the second scheme, all current LWRs operate for a 40-yr lifetime, producing a total of 84,000 tonnes IHM of spent fuel. This spent fuel is treated using a pyrochemical process in which 98.4% of the uranium and 99.8% of the neptunium, plutonium, americium, and curium are extracted and fabricated into ALMR fuel, with the reprocessing wastes destined for the repository. The ALMR requires this fuel for its startup and first two reloads; thereafter, it is self-sufficient. Spent ALMR fuel is also pyrochemically reprocessed: 99.9% of the transuranics is recovered and recycled into ALMR fuel, and the wastes are placed in the repository. Thus, in the second scheme, the repository contains the wastes from reprocessing all of the LWR spent fuel plus the maximum amount of ALMR reprocessing wastes allowed in the repository based on its heat generation limit

  1. Actinides-lanthanides (neodymium) separation by electrolytic extraction in molten fluoride media; Separation actinides-lanthanides (neodyne) par extraction electrolytique en milieux fluorures fondus

    Energy Technology Data Exchange (ETDEWEB)

    Hamel, C

    2005-02-15

    The aim of this thesis is to assess the potentialities of pyrochemical processes for future nuclear fuels and Generation IV reactors (more particularly molten salt reactors). This study concerns the Actinides-Lanthanides and Lanthanides-Solvent separation by electrolytic extraction in molten fluoride media at high temperature. Three elements are selected for this study: neodymium (NdF{sub 3}), uranium (UF{sub 4}) and plutonium (PuF{sub 3}). Firstly, the electrochemical study of these three compounds in molten fluoride media is performed to evaluate the separations. Electrodeposition processes are studied and the values of formal potentials of U(III)/U(0), Pu(III)/Pu(0) and Nd(III)/Nd(0) are obtained in LiF-CaF{sub 2} eutectic mixture. Thermodynamically, the values of potentials differences are enough to separate U-Nd and Pu-Nd with a yield of extraction of 99.99%; this value is just sufficient for the Pu-Nd separation. Concerning the Nd-solvent separation this potential difference is too small. Next, the electrodeposition of solid metals on inert electrodes is performed. This study showed that the uranium and neodymium deposits are unstable in several fluoride media. In addition, the presence of salts in the dendritic metal is observed for the U solid deposits. Finally, a reactive cathode is used to improve these separation results and the shape of the deposits. The experimental results on nickel electrodes showed an improvement of the Pu-Nd separation and the Nd-solvent separation with the depolarization phenomenon of the metal deposit on the nickel. Moreover, U and Nd metal are stabilized in the alloy which allows the elimination of reactions with the solvent as observed for the solid deposit. The formation of liquids alloys makes also easier the recovery of these three. (author)

  2. Actinides-lanthanides (neodymium) separation by electrolytical extraction in molten fluoride media; Separation actinides-lanthanides (neodyne) par extraction electrolytique en milieux fluorures fondus

    Energy Technology Data Exchange (ETDEWEB)

    Hamel, C

    2005-02-15

    The aim of this thesis is to assess the potentialities of pyrochemical processes for futur nuclear fuels and Generation IV reactors (more particularly molten salt reactors). This study concerns the Actinides-Lanthanides and Lanthanides-Solvent separation by electrolytical extraction in molten fluoride media at high temperature. Three elements are selected for this study: neodymium (NdF{sub 3}), uranium (UF{sub 4}) and plutonium (PuF{sub 3}). Firstly, the electrochemical study of these three compounds in molten fluoride media is performed to evaluate the separations. Electrodeposition processes are studied and the values of formal potentials of U(III)/U(0), Pu(III)/Pu(0) and Nd(III)/Nd(0) are obtained in LiF-CaF{sub 2} eutectic mixture. Thermodynamically, the values of potentials differences are enough to separate U-Nd and Pu-Nd with a yield of extraction of 99.99%; this value is just sufficient for the Pu-Nd separation. Concerning the Nd-solvent separation this potential difference is too small. Next, the electrodeposition of solid metals on inert electrodes is performed. This study showed that the uranium and neodymium deposits are unstable in several fluoride media. In addition, the presence of salts in the dendritic metal is observed for the U solid deposits. Finally, a reactive cathode is used to improve these separation results and the shape of the deposits. The experimental results on nickel electrodes showed an improvement of the Pu-Nd separation and the Nd-solvent separation with the depolarisation phenomenon of the metal deposit on the nickel. Moreover, U and Nd metal are stabilized in the alloy which allows the elimination of reactions with the solvent as observed for the solid deposit. The formation of liquids alloys makes also easier the recovery of these three. (author)

  3. 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

  4. Actinide coordination sphere in various U, Np and Pu nitrato coordination complexes

    International Nuclear Information System (INIS)

    Waste management of nuclear fuel represents one of the major environmental concerns of the decade. To recycle fissile valuable materials, intimate knowledge of complexation mechanisms involved in the solvent extraction processes is indispensable. Evolution of the actinide coordination sphere of AnO2(NO3)2TBP-type complexes (an = U, Np, Pu; TBP = tributylphosphate) with the actinide valence state have been probed by XAS at the metal LIII edge. Dramatic changes in the actinide coordination sphere appeared when the An(VI) metal is reduced to An(IV). However, no significant evolution in the actinide environment has been noticed across the series UO22+, NpO22+ and PuO22+. (au)

  5. Organophosphorus reagents in actinide separations: Unique tools for production, cleanup and disposal

    Energy Technology Data Exchange (ETDEWEB)

    Nash, K. L.

    2000-01-12

    Interactions of actinide ions with phosphate and organophosphorus reagents have figured prominently in nuclear science and technology, particularly in the hydrometallurgical processing of irradiated nuclear fuel. Actinide interactions with phosphorus-containing species impact all aspects from the stability of naturally occurring actinides in phosphate mineral phases through the application of the bismuth phosphate and PUREX processes for large-scale production of transuranic elements to the development of analytical separation and environment restoration processes based on new organophosphorus reagents. In this report, an overview of the unique role of organophosphorus compounds in actinide production, disposal, and environment restoration is presented. The broad utility of these reagents and their unique chemical properties is emphasized.

  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. Basic research on solvent extraction of actinide cations with diamide compounds

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Yuji [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-11-01

    Newly synthesized 4 diamide compounds were tested for solvent extraction of actinide cations. It is obvious that N,N`-dimethyl-N,N`-dihexyl-3-oxapentanediamide (DMDHOPDA) can extract Eu(III), Th(IV), U(VI), Np(V), and Am(III) into organic solvent. Other 3 diamides hardly extract actinide ions, which is supposed that the reasons come from the difference of their chemical structures. In the synergistic extraction with a diamide and thenoyltrifluoroacetone (TTA), all diamides work as a extractant. Furthermore, by examining extracted species, it was confirmed that there are 4 kinds of chemical species of actinides with diamide and TTA. Finally, the mutual separation method of actinide (III), (IV), (V) and (VI) ions by solvent extraction using DMDHOPDA and TTA were developed. (author). 147 refs.

  8. Fission product and actinide data evaluations for ENDF/B--V

    Energy Technology Data Exchange (ETDEWEB)

    Schenter, R.E.

    1978-05-01

    The planned content and performance of fission product and actinide nuclide evaluations for the ENDF/B-V collection of data are reviewed. Representative values of parameters for a few nuclides are shown. 10 figures, 5 tables. (RWR)

  9. SACSESS – the EURATOM FP7 project on actinide separation from spent nuclear fuels

    Directory of Open Access Journals (Sweden)

    Bourg Stéphane

    2015-12-01

    Full Text Available Recycling of actinides by their separation from spent nuclear fuel, followed by transmutation in fast neutron reactors of Generation IV, is considered the most promising strategy for nuclear waste management. Closing the fuel cycle and burning long-lived actinides allows optimizing the use of natural resources and minimizing the long-term hazard of high-level nuclear waste. Moreover, improving the safety and sustainability of nuclear power worldwide. This paper presents the activities striving to meet these challenges, carried out under the Euratom FP7 collaborative project SACSESS (Safety of Actinide Separation Processes. Emphasis is put on the safety issues of fuel reprocessing and waste storage. Two types of actinide separation processes, hydrometallurgical and pyrometallurgical, are considered, as well as related aspects of material studies, process modeling and the radiolytic stability of solvent extraction systems. Education and training of young researchers in nuclear chemistry is of particular importance for further development of this field.

  10. Nuclear data uncertainty analysis on a minor actinide burner for transmuting spent fuel

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hangbok

    1998-08-01

    A comprehensive sensitivity and uncertainty analysis was performed on a 1200 MWt minor actinides burner designed for a low burnup reactivity swing, negative doppler coefficient, and low sodium void worth. Sensitivities of the performance parameters were generated using depletion perturbation methods for the constrained close fuel cycle of the reactor. The uncertainty analysis was performed using the sensitivity and covariance data taken from ENDF-B/V and other published sources. The uncertainty analysis of a liquid metal reactor for burning minor actinide has shown that uncertainties in the nuclear data of several key minor actinide isotopes can introduce large uncertainties in the predicted performance of the core. The relative uncertainties in the burnup swing, doppler coefficient, and void worth were conservatively estimated to be 180 %, 97 %, and 46 %, respectively. An analysis was performed to prioritize the minor actinide reactions for reducing the uncertainties. (author). 41 refs., 17 tabs., 1 fig.

  11. Status of the French research program for actinides and fission products partitioning and transmutation

    International Nuclear Information System (INIS)

    The global energy context pleads in favour of a sustainable development of nuclear energy since the demand for energy will likely increase, whereas resources will tend to get scarcer and the prospect of global warming will drive down the consumption of fossil fuel sources. How we deal with radioactive waste is crucial in this context. The production of nuclear energy in France has been associated, since its inception, with the optimization of radioactive waste management, including the partitioning and the recycling of recoverable energetic materials. From the start, the CEA has devoted considerable effort to management of the back end of the cycle. It furnished the process and techniques used in the La Hague facility to extract the re-usable materials, uranium and plutonium, and condition the resulting waste. Towards the end of the 1960's, it developed the process of vitrification for highly active waste that has become the world reference. The public's concern regarding the log-term waste management made the French Government to delay the implementation of the geological disposal and to prepare a law, passed on December 30, 1991, requesting in particular the study for fifteen years of solutions and processes for: minimizing the quantity and the hazardousness of waste, via partitioning and transmutation, either reversibly or irreversibly disposing the waste in deep geological formation, waste conditioning and long-term interim storage. We present in this paper the French program and an overview of the results obtained by the research conducted in the framework of the law on partitioning and transmutation between 1991 and 2005. Over these past fifteen years, all of the P and T research has been conducted by CEA in close collaboration with the CNRS and French universities, and with the support of partners from industry (EDF, COGEMA, FRAMATOME-ANP). Significant results have been obtained and changed the prospects for nuclear waste management; these results are

  12. Immobilization of actinide wastes in ceramics for long-term disposal

    OpenAIRE

    Soe, Khin Soe

    2006-01-01

    Glass can undergo devitrification with time and the incorporation of actinides with their alpha-decay in MeV-range due to compacted alpha-recoiled irradiation over 10^6 years storage leads to expansion and phase transformation of nuclear waste glasses. Moreover, the maximum tolerable amount of actinides that can be incorporated in glass is approximately 5%. The development of ceramics adapted for nuclear-waste immobilization is the focus of this dissertation. The yttria-stabilized zirconia c...

  13. An instrument for the investigation of actinides with spin resolved photoelectron spectroscopy and bremsstrahlung isochromat spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yu, S.-W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Tobin, J. G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chung, B. W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2011-01-01

    A new system for spin resolved photoelectron spectroscopy and bremsstrahlung isochromat spectroscopy has been built and commissioned at Lawrence Livermore National Laboratory for the investigation of the electronic structure of the actinides.Actinide materials are very toxic and radioactive and therefore cannot be brought to most general user facilities for spectroscopic studies. The technical details of the new system and preliminary data obtained therein will be presented and discussed.

  14. Multidimensionally-constrained relativistic mean-field study of triple-humped barriers in actinides

    OpenAIRE

    Zhao, Jie; Lu, Bingnan; Vretenar, Dario; Zhao, En-Guang; Zhou, Shan-Gui

    2014-01-01

    Potential energy surfaces (PES's) of actinide nuclei are characterized by a two-humped barrier structure. At large deformations beyond the second barrier the occurrence of a third one was predicted by Mic-Mac model calculations in the 1970s, but contradictory results were later reported. In this paper, triple-humped barriers in actinide nuclei are investigated with covariant density functional theory (CDFT). Calculations are performed using the multidimensionally-constrained relativistic mean...

  15. Production of actinide isotopes in simulated PWR fuel and their influence on inherent neutron emission

    International Nuclear Information System (INIS)

    This report describes calculations that examine the sensitivity of actinide isotopes to various reactor parameters. The impact of actinide isotope build-up, depletion, and decay on the neutron source rate in a spent-fuel assembly is determined, and correlations between neutron source rates and spent-fuel characteristics such as exposure, fissile content, and plutonium content are established. The application of calculations for evaluating experimental results is discussed

  16. SACSESS – the EURATOM FP7 project on actinide separation from spent nuclear fuels

    OpenAIRE

    Bourg Stéphane; Geist Andreas; Narbutt Jerzy

    2015-01-01

    Recycling of actinides by their separation from spent nuclear fuel, followed by transmutation in fast neutron reactors of Generation IV, is considered the most promising strategy for nuclear waste management. Closing the fuel cycle and burning long-lived actinides allows optimizing the use of natural resources and minimizing the long-term hazard of high-level nuclear waste. Moreover, improving the safety and sustainability of nuclear power worldwide. This paper presents the activities strivin...

  17. Radiochemical separation of actinides for their determination in environmental samples and waste products

    Energy Technology Data Exchange (ETDEWEB)

    Gleisberg, B. [Nuclear Engineering and Analytics Rossendorf, Inc. (VKTA), Dresden (Germany)

    1997-03-01

    The determination of low level activities of actinides in environmental samples and waste products makes high demands on radiochemical separation methods. Artificial and natural actinides were analyzed in samples form the surrounding areas of NPP and of uranium mines, incorporation samples, solutions containing radioactive fuel, solutions and solids resutling from the process, and in wastes. The activities are measured by {alpha}-spectrometry and {gamma}-spectrometry. (DG)

  18. Actinides in molecules: exotic properties probed by X-ray Absorption Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Den Auwer, C.; Moisy, P.; Guilbaud, P.; Guillaumont, D.; Simoni, E.; Conradson, S.D

    2004-07-01

    Dealing with actinide elements in molecular chemistry may result in particularly attractive and exotic physico-chemical properties. In solution, one of the spectroscopic tools able to selectively probe the structural or electronic properties of these molecules is the X-ray absorption process. Different aspects of absorption edge or EXAFS analysis related to actinide studies are presented, including phenomenological and semi-quantitative approaches. (authors)

  19. DAE-BRNS symposium on spectroscopy of lanthanides and actinides (SLA-99)

    International Nuclear Information System (INIS)

    Spectroscopy of lanthanides and actinides, due to the rich and complex interactions of the f electrons, is of immense interest to basic sciences and technology. This volume covers both basic and applied aspects of the spectroscopy of lanthanides and actinides and also include the recent developments and emerging areas. The papers have been classified in several broad categories namely theoretical studies, high resolution spectroscopy, laser spectroscopy, solid state spectroscopy, analytical spectroscopy, optics and instrumentation and applications. Papers relevant to INIS are indexed separately

  20. Actinide partitioning and transmutation program progress report, October 1, 1976--March 31, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Blomeke, J. O.; Tedder, D. W. [comps.

    1977-01-01

    Experimental work on the 16 tasks comprising the Actinide Partitioning and Transmutation Program was initiated at the various sites. This work included the development of conceptual material balance flowsheets which define integrated waste systems supporting an LWR fuel reprocessing plant and a mixed (U-Pu) oxide fuel refabrication plant. In addition, waste subsystems were defined for experimental evaluation. Computer analysis of partitioning-transmutation, utilizing an LMFBR for transmutation, was completed for both constant and variable waste actinide generation rates.

  1. Why Faster is Better : On Minor Actinide Transmutation in Hard Neutron

    OpenAIRE

    Westlén, Daniel

    2007-01-01

    In this thesis, options for efficient transmutation of transuranium elements are discussed. The focus is on plutonium, americium and curium mainly because of their long-term contribution to the radiotoxicity of spent nuclear fuel. Two innovative helium-cooled core designs are proposed, dedicated to the transmutation of actinides. The performance of the more promising of the two is studied in realistic transient fuel cycle scenarios. During the 1150 day irradiation cycle, a minor actinide cons...

  2. Emergence of californium as the second transitional element in the actinide series

    OpenAIRE

    Cary, Samantha K.; Vasiliu, Monica; Baumbach, Ryan E.; Stritzinger, Jared T.; GREEN, THOMAS D.; Diefenbach, Kariem; Cross, Justin N.; Knappenberger, Kenneth L.; Liu, Guokui; Silver, Mark A.; DePrince, A. Eugene; Polinski, Matthew J.; Van Cleve, Shelley M.; House, Jane H.; Kikugawa, Naoki

    2015-01-01

    A break in periodicity occurs in the actinide series between plutonium and americium as the result of the localization of 5f electrons. The subsequent chemistry of later actinides is thought to closely parallel lanthanides in that bonding is expected to be ionic and complexation should not substantially alter the electronic structure of the metal ions. Here we demonstrate that ligation of californium(III) by a pyridine derivative results in significant deviations in the properties of the resu...

  3. N,N-dialkyl-2-hydroxyacetamides for modifier-free separation of trivalent actinides from nitric acid medium

    Energy Technology Data Exchange (ETDEWEB)

    Prathibha, T.; Kumaresan, R.; Selvan, B. Robert; Venkatesan, K.A.; Antony, M.P.; Vasudeva Rao, P.R. [Indira Gandhi Centre for Atomic Research, Kalpakkam (India). Fuel Chemistry Div.

    2016-07-01

    The alkyl derivatives of N,N,-dialkyl-2-hydroxyacetamide (DAHyA), namely, N,N,-dihexyl-2-hydroxyacetamide (DHHyA), N,N,-dioctyl-2-hydroxyacetamide (DOHyA), N,N,-didecyl-2-hydroxyacetamide (DDHyA), were synthesized and characterized by FT-IR, and NMR spectroscopy. The extraction behaviour of Am(III) in a solution of DAHyA in n-dodecane was studied as a function of various parameters to evaluate the feasibility of using DAHyA for partitioning of trivalent actinides from high-level liquid waste (HLLW). The distribution ratio of Am(III) (D{sub Am(III)}) in 0.1 M DAHyA/n-DD increased from 10{sup -4} to > 200 with increase in nitric acid concentration from 1 M to 6 M. A D{sub Am(III)} value 10-70 was obtained in a nitric acid concentration range from 3-4 M. The extraction of Am(III) in 0.1 M DAHyA/n-dodecane decreased in the order DHHyA > DOHyA > DDHyA. The third-phase formation behaviour of nitric acid and neodymium (III) in 0.2 M DAHyA/n-dodecane was studied. Near stoichiometric amount of neodymium (III) can be loaded in octyl and decyl derivatives without any third-phase formation from 3-4 M nitric acid medium. Unlike other extractants, the loaded trivalent metal ion in DAHyA can be recovered even with 1 M nitric acid. Therefore, the study revealed that N,N,-dialkyl-2-hydroxyacetamides are promising candidates for partitioning the trivalent actinides from HLLW.

  4. Combining theoretical chemistry and Xanes multi-edge experiments to probe actinide valence states

    International Nuclear Information System (INIS)

    Both structural and electronic properties of the actinide cations are of fundamental interest in order to describe the intramolecular interactions. The 5f and 6d orbitals are the first partially or totally vacant states of these elements and their properties reflect the nature of the actinide-ligand bond. Because of its chemical and orbital selectivities, XANES spectroscopy is useful to probe the actinides' frontier orbitals and then understand the cation reactivity toward chelating ligands. The actinide L3 edge contains structural information on the coordination polyhedron because of important scattering features. But very little electronic information can be extracted, due to the short core-hole lifetime, broadening the edge signal. On the other hand, the actinide M4,5 edges provide a better resolution and allow one to achieve electronic and structural information. Furthermore, coupling simulations of the experimental spectra and quantum chemical calculations lead to quantitative information such as the determination of the actinide coordination sphere and its effective charge. (authors)

  5. Combining theoretical chemistry and Xanes multi-edge experiments to probe actinide valence states

    Energy Technology Data Exchange (ETDEWEB)

    Fillaux, C.; Guilbaud, Ph.; Guillaumont, D.; Moisy, Ph.; Den Auwer, Ch. [CEA Valrho, Dir. de l' Energie Nucleaire (DEN/DRCP/SCPS), 30 - Marcoule (France); Berthet, J.C. [CEA Saclay, Dept. de Recherche sur l' Etat Condense, les Atomes et les Molecules (DSM/DRECAM/SCM), 91 - Gif sur Yvette (France); Conradsonc, St.D. [Los Alamos National Laboratory, Los Alamos, NM (United States); Hennig, C. [Forschungszentrum Rossendorf, ROBL at ESRF, 38 - Grenoble (France); Roques, J.; Simoni, E. [Institut de Physique Nucleaire, 91 - Orsay (France); Shuh, D.K.; Tyliszczak, T.; Castro-Rodriguez, I. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States)

    2007-10-15

    Both structural and electronic properties of the actinide cations are of fundamental interest in order to describe the intramolecular interactions. The 5f and 6d orbitals are the first partially or totally vacant states of these elements and their properties reflect the nature of the actinide-ligand bond. Because of its chemical and orbital selectivities, XANES spectroscopy is useful to probe the actinides' frontier orbitals and then understand the cation reactivity toward chelating ligands. The actinide L3 edge contains structural information on the coordination polyhedron because of important scattering features. But very little electronic information can be extracted, due to the short core-hole lifetime, broadening the edge signal. On the other hand, the actinide M4,5 edges provide a better resolution and allow one to achieve electronic and structural information. Furthermore, coupling simulations of the experimental spectra and quantum chemical calculations lead to quantitative information such as the determination of the actinide coordination sphere and its effective charge. (authors)

  6. Reduction of minor actinides for recycling in a light water reactor

    International Nuclear Information System (INIS)

    The aim of actinide transmutation from spent nuclear fuel is the reduction in mass of high-level waste which must be stored in geological repositories and the lifetime of high-level waste; these two achievements will reduce the number of repositories needed, as well as the duration of storage. The present work is directed towards the evaluation of an advanced nuclear fuel cycle in which the minor actinides (Np, Am and Cm) could be recycled to remove most of the radioactive material; a reference of actinides production in standard nuclear fuel of uranium at the end of its burning in a BWR is first established, after a design of fuel rod containing 6% of minor actinides in a matrix of uranium from the enrichment lines is proposed, then 4 fuel rods of standard uranium are replaced by 4 actinides bars to evaluate the production and transmutation of them and finally the minor actinides reduction in the fuel is evaluated. In the development of this work the calculation tool are the codes: Intrepin-3, Casmo-4 and Simulate-3. (Author)

  7. Characterization Of Actinides In Simulated Alkaline Tank Waste Sludges And Leachates

    International Nuclear Information System (INIS)

    In this project, both the fundamental chemistry of actinides in alkaline solutions (relevant to those present in Hanford-style waste storage tanks), and their dissolution from sludge simulants (and interactions with supernatants) have been investigated under representative sludge leaching procedures. The leaching protocols were designed to go beyond conventional alkaline sludge leaching limits, including the application of acidic leachants, oxidants and complexing agents. The simulant leaching studies confirm in most cases the basic premise that actinides will remain in the sludge during leaching with 2-3 M NaOH caustic leach solutions. However, they also confirm significant chances for increased mobility of actinides under oxidative leaching conditions. Thermodynamic data generated improves the general level of experiemental information available to predict actinide speciation in leach solutions. Additional information indicates that improved Al removal can be achieved with even dilute acid leaching and that acidic Al(NO3)3 solutions can be decontaminated of co-mobilized actinides using conventional separations methods. Both complexing agents and acidic leaching solutions have significant potential to improve the effectiveness of conventional alkaline leaching protocols. The prime objective of this program was to provide adequate insight into actinide behavior under these conditions to enable prudent decision making as tank waste treatment protocols develop.

  8. CHARACTERIZATION OF ACTINIDES IN SIMULATED ALKALINE TANK WASTE SLUDGES AND LEACHATES

    Energy Technology Data Exchange (ETDEWEB)

    Nash, Kenneth L.

    2008-11-20

    In this project, both the fundamental chemistry of actinides in alkaline solutions (relevant to those present in Hanford-style waste storage tanks), and their dissolution from sludge simulants (and interactions with supernatants) have been investigated under representative sludge leaching procedures. The leaching protocols were designed to go beyond conventional alkaline sludge leaching limits, including the application of acidic leachants, oxidants and complexing agents. The simulant leaching studies confirm in most cases the basic premise that actinides will remain in the sludge during leaching with 2-3 M NaOH caustic leach solutions. However, they also confirm significant chances for increased mobility of actinides under oxidative leaching conditions. Thermodynamic data generated improves the general level of experiemental information available to predict actinide speciation in leach solutions. Additional information indicates that improved Al removal can be achieved with even dilute acid leaching and that acidic Al(NO3)3 solutions can be decontaminated of co-mobilized actinides using conventional separations methods. Both complexing agents and acidic leaching solutions have significant potential to improve the effectiveness of conventional alkaline leaching protocols. The prime objective of this program was to provide adequate insight into actinide behavior under these conditions to enable prudent decision making as tank waste treatment protocols develop.

  9. Calculation of binary phase diagrams between the actinide elements, rare earth elements, and transition metal elements

    International Nuclear Information System (INIS)

    Attempts were made to apply the Kaufman method of calculating binary phase diagrams to the calculation of binary phase diagrams between the rare earths, actinides, and the refractory transition metals. Difficulties were encountered in applying the method to the rare earths and actinides, and modifications were necessary to provide accurate representation of known diagrams. To calculate the interaction parameters for rare earth-rare earth diagrams, it was necessary to use the atomic volumes for each of the phases: liquid, body-centered cubic, hexagonal close-packed, and face-centered cubic. Determination of the atomic volumes of each of these phases for each element is discussed in detail. In some cases, empirical means were necessary. Results are presented on the calculation of rare earth-rare earth, rare earth-actinide, and actinide-actinide diagrams. For rare earth-refractory transition metal diagrams and actinide-refractory transition metal diagrams, empirical means were required to develop values for the enthalpy of vaporization for rare earth elements and values for the constant (C) required when intermediate phases are present. Results of using the values determined for each element are presented

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

    International Nuclear Information System (INIS)

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

  11. Actinides reduction by recycling in a thermal reactor; Reduccion de actinidos por reciclado en un reactor termico

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-10-15

    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)

  12. Electrochemical behavior of actinides and actinide nitrides in LiCl-KCl eutectic melts

    International Nuclear Information System (INIS)

    The redox potentials of the U3+/U, Np3+/Np and Pu3+/Pu couples at Mo, Cd and Bi electrodes in LiCl-KCl eutectic melt containing UCl3, NpCl3 and PuCl3, respectively, were evaluated by electrochemical measurements at the temperature range between 723 and 823K. The standard potentials of the U3+/U, Np3+/Np and Pu3+/Pu couples versus the Ag+/Ag (1wt.% AgCl) reference electrode were given by the following equations: EU3+/U0=-1.8647+0.000798xT, ENp3+/Np0=-2.0298+0.000706xT and EPu3+/Pu0=-2.232+0.00094xT, where E values are in volts, T in kelvin. The differences between the redox potentials at Mo electrode and those at liquid metal electrodes were attributable to the lowering in the activities of U, Pu and Np in liquid metal phases according to the alloy formation. Similarly, the anodic dissolutions of UN, NpN and PuN were observed at about 0.7V more positive potential than those of U, Np and Pu, respectively, since the stabilization of U, Np and Pu by nitriding lowered the activities of U, Np and Pu, respectively, in the solid phase

  13. Sensitivity analysis of minor actinides transmutation to physical and technological parameters

    Directory of Open Access Journals (Sweden)

    Kooyman Timothée

    2015-01-01

    Full Text Available Minor actinides transmutation is one of the three main axis defined by the 2006 French law for management of nuclear waste, along with long-term storage and use of a deep geological repository. Transmutation options for critical systems can be divided in two different approaches: (a homogeneous transmutation, in which minor actinides are mixed with the fuel. This exhibits the drawback of “polluting” the entire fuel cycle with minor actinides and also has an important impact on core reactivity coefficients such as Doppler Effect or sodium void worth for fast reactors when the minor actinides fraction increases above 3 to 5% depending on the core; (b heterogeneous transmutation, in which minor actinides are inserted into transmutation targets which can be located in the center or in the periphery of the core. This presents the advantage of decoupling the management of the minor actinides from the conventional fuel and not impacting the core reactivity coefficients. In both cases, the design and analyses of potential transmutation systems have been carried out in the frame of Gen IV fast reactor using a “perturbation” approach in which nominal power reactor parameters are modified to accommodate the loading of minor actinides. However, when designing such a transmutation strategy, parameters from all steps of the fuel cycle must be taken into account, such as spent fuel heat load, gamma or neutron sources or fabrication feasibility. Considering a multi-recycling strategy of minor actinides, an analysis of relevant estimators necessary to fully analyze a transmutation strategy has been performed in this work and a sensitivity analysis of these estimators to a broad choice of reactors and fuel cycle parameters has been carried out. No threshold or percolation effects were observed. Saturation of transmutation rate with regards to several parameters has been observed, namely the minor actinides volume fraction and the irradiation time

  14. Minor actinides partitioning and transmutation technology in France

    International Nuclear Information System (INIS)

    real solutions derived from the La Hague process, the CEA demonstrated the feasibility of extracting minor actinides using a process that can be extrapolated on the industrial scale. The CEA also conducted programmes proving the technical feasibility of the elimination of minor actinides by transmutation. With the help of the CNRS (France) in particular we developed high strength ceramic matrices to contain any radionuclides extracted by enhanced separation that might be deemed unsuitable for transmutation. (author)

  15. Paving the way for the synthesis of a series of divalent actinide complexes: a theoretical perspective.

    Science.gov (United States)

    Wu, Q-Y; Lan, J-H; Wang, C-Z; Cheng, Z-P; Chai, Z-F; Gibson, J K; Shi, W-Q

    2016-02-21

    Recently, the +2 formal oxidation state in soluble molecular complexes for lanthanides (La-Nd, Sm-Lu) and actinides (Th and U) has been discovered [W. J. Evans, et al., J. Am. Chem. Soc., 2011, 133, 15914; J. Am. Chem. Soc., 2012, 134, 8420; J. Am. Chem. Soc., 2013, 135, 13310; Chem. Sci., 2015, 6, 517]. To explore the nature of the bonding and stabilities of the low-valent actinide complexes, a series of divalent actinide species, [AnCp'3](-) (An[double bond, length as m-dash]Th-Am, Cp' = [η(5)-C5H4(SiMe3)](-)) have been investigated in THF solution using scalar relativistic density functional theory. The electronic structures and electron affinity properties were systematically studied to identify the interactions between the +2 actinide ions and Cp' ligands. The ground state electron configurations for the [AnCp'3](-) species are [ThCp'3](-) 6d(2), [PaCp'3](-) 5f(2)6d(1), [UCp'3](-) 5f(3)6d(1), [NpCp'3](-) 5f(5), [PuCp'3](-) 5f(6), and [AmCp'3](-) 5f(7), respectively, according to the MO analysis. The total bonding energy decreases from the Th- to the Am-complex and the electrostatic interactions mainly dominate the bonding between the actinide atom and ligands. The electron affinity analysis suggests that the reduction reaction of AnCp'3→ [AnCp'3](-) should become increasingly facile across the actinide series from Th to Am, in accord with the known An(iii/ii) reduction potentials. This work expands the knowledge on the low oxidation state chemistry of actinides, and further motivates and guides the synthesis of related low oxidation state compounds of 5f elements.

  16. Structure of early actinides(V) in acidic solutions

    Energy Technology Data Exchange (ETDEWEB)

    Di Giandomenico, M.V.; Le Naour, C.; Simoni, E. [CNRS/Univ. Paris-Sud, Inst. de Physique Nucleaire, Orsay (France); Guillaumont, D.; Moisy, P.; Den Auwer, C. [CEA Marcoule, DHN/DRCP/SCPS, Bagnols sur Ceze (France); Hennig, C. [Forschungszentrum Rossendorf, Dresden (Germany); Conradson, S.D. [Los Alamos National Lab., Los Alamos, NM (United States)

    2009-07-01

    Protactinium occupies a key position in the actinide series between thorium and uranium. In aqueous acidic solution, it is stable at oxidation state (V), occurring either as an oxocation or as a naked ion, depending on the media. Very few structural information on the hydration sphere of Pa(V) in acidic medium is available, in particular in hydrofluoric acid. Combined EXAFS and theoretical calculations have been used in this work to characterize the protactinium coordination sphere at various HF concentrations. The correlation of the XAFS data with quantum chemical calculations provides complementary structural and electronic models from ab initio techniques. At HF concentrations from 0.5 to 0.05 M, both theoretical calculations and EXAFS data suggest that the protactinium coordination sphere is mainly composed of fluoride ions. At the lowest HF concentration, the occurrence of a monooxo bond is observed with EXAFS, in agreement with the literature. A comparison of these data with related neptunium(V) and plutonium(V) diooxocations in perchloric acid is also presented. (orig.)

  17. Structure of early actinides(V) in acidic solutions

    International Nuclear Information System (INIS)

    Protactinium occupies a key position in the actinide series between thorium and uranium. In aqueous acidic solution, it is stable at oxidation state (V), occurring either as an oxocation or as a naked ion, depending on the media. Very few structural information on the hydration sphere of Pa(V) in acidic medium is available, in particular in hydrofluoric acid. Combined EXAFS and theoretical calculations have been used in this work to characterize the protactinium coordination sphere at various HF concentrations. The correlation of the XAFS data with quantum chemical calculations provides complementary structural and electronic models from ab initio techniques. At HF concentrations from 0.5 to 0.05 M, both theoretical calculations and EXAFS data suggest that the protactinium coordination sphere is mainly composed of fluoride ions. At the lowest HF concentration, the occurrence of a monooxo bond is observed with EXAFS, in agreement with the literature. A comparison of these data with related neptunium(V) and plutonium(V) diooxocations in perchloric acid is also presented. (orig.)

  18. Effects of organic degradation products on the sorption of actinides

    International Nuclear Information System (INIS)

    Previous work has shown that products from the chemical degradation of cellulosic matter can significantly reduce sorption of uranium(VI) and plutonium(IV) on geological materials. Uranium(IV) batch sorption experiments have now been performed to study the effect of organic degradation products in a reducing environment. Thorium(IV) sorption has also been studied since thorium is an important radioelement in its own right and has potential use as a simulant for other tetravalent actinides. Sorption onto London clay, Caithness flagstones and St. Bees sandstone was investigated. Experimental conditions were chosen to simulate both those expected close to cementitious repository (pH ∝ 11) and at the edge of the zone of migration of the alkaline plume (pH ∝ 8). Work was carried out with both authentic degradation products and with gluconate, acting as a well-characterized simulant for cellulosic degradation products. The results show that the presence of organic species can cause a reduction in sorption. This is especially so in the presence of a high concentration of gluconate ions, but the reduction is significantly less with authentic degradation products. (orig.)

  19. Thoughts on environmental actinide research-future and present situation

    International Nuclear Information System (INIS)

    Thoughts on environmental actinides, especially transuranium elements, are presented with emphasis on present situation and future researches. It is since 1945 that man has been in direct relationship to the significant quantities of such transuranium elements, although Pu was discovered in 1942 to exist in very small quantities in nature. Substantial amounts of these elements (Np, Pu, Am) have been distributed in the environment mainly as the result of nuclear weapon testing, followed by accident of satellite and release of radioactive substances from nuclear facilities. Chernobyl nuclear power plant accident might serve as a most recent example of such release. Considerable efforts have been devoted to the investigation of the processes involved in the transfer of radionuclides in the environment and how these can be influenced. And, many data (levels and distribution) and knowledge to understand these processes have been obtained and accumulated. The final purpose in all the research was the protection of the human being. The present trends for environmental radioactivity research (or radioecology) involves a further development of models, speciation of radionuclides, tracer studies and countermeasures of other species than man in radiological protection. Joint researches between radioecologists and specialists such as meteorology, oceanography, geology, botany, statistics and so on are more and more needed to make one of the most fascinating environmental sciences. Finally, an effort should be made to develop radioecology into a more hypothesis-oriented science, as mentioned by Platt. (author)

  20. Functionalization of mesoporous materials for lanthanide and actinide extraction.

    Science.gov (United States)

    Florek, Justyna; Giret, Simon; Juère, Estelle; Larivière, Dominic; Kleitz, Freddy

    2016-10-14

    Among the energy sources currently available that could address our insatiable appetite for energy and minimize our CO2 emission, solar, wind, and nuclear energy currently occupy an increasing portion of our energy portfolio. The energy associated with these sources can however only be harnessed after mineral resources containing valuable constituents such as actinides (Ac) and rare earth elements (REEs) are extracted, purified and transformed into components necessary for the conversion of energy into electricity. Unfortunately, the environmental impacts resulting from their manufacture including the generation of undesirable and, sometimes, radioactive wastes and the non-renewable nature of the mineral resources, to name a few, have emerged as challenges that should be addressed by the scientific community. In this perspective, the recent development of functionalized solid materials dedicated to selective elemental separation/pre-concentration could provide answers to several of the above-mentioned challenges. This review focuses on recent advances in the field of mesoporous solid-phase (SP) sorbents designed for REEs and Ac liquid-solid extraction. Particular attention will be devoted to silica and carbon sorbents functionalized with commonly known ligands, such as phosphorus or amide-containing functionalities. The extraction performances of these new systems are discussed in terms of sorption capacity and selectivity. In order to support potential industrial applications of the silica and carbon-based sorbents, their main drawbacks and advantages are highlighted and discussed.

  1. Actinide recycle potential in the IFR [Integral Fast Reactor

    International Nuclear Information System (INIS)

    Rising concern about the greenhouse effect reinforces the need to reexamine the question of a next-generation reactor concept that can contribute significantly toward substitution for fossil-based energy generation. Even with only the nuclear capacity on-line today, world-wide reasonably assured uranium resources would last for only about 50 years. If nuclear is to make a significant contribution, breeding is a fundamental requirement. Uranium resources can then be extended by two orders of magnitude, making nuclear essentially a renewable energy source. The key technical elements of the IFR concept are metallic fuel and fuel cycle technology based on pyroprocessing. Pyroprocessing is radically different from the conventional PUREX reprocessing developed for the LWR oxide fuel. Chemical feasibility of pyroprocessing has been demonstrated. The next major step in the IFR development program will be the full-scale pyroprocessing demonstration to be carried out in conjunction with EBR-II. IFR fuel cycle closure based on pyroprocessing can also have a dramatic impact on the waste management options, and in particular on the actinide recycling. 6 figs

  2. Outcomes on Oxide Fuel Development for Minor Actinides Recycling

    International Nuclear Information System (INIS)

    A state of the art review is given of minor actinide (MA)-bearing oxide fuel development for sodium fast reactors (SFRs) and accelerator driven systems (ADS). The homogeneous recycle option in SFRs, where small amounts of MAs are diluted in (U,Pu)O2-x driver fuels, emerges as a technically sound approach, reinforced by national and international programmes. Its technology readiness level is appropriate to implement irradiation tests from pin to bundle scale. Regarding the heterogeneous recycle option in SFRs, a comprehensive database regarding inert matrix fuels is available as the result of ~35 irradiation tests. The promising results gained with MgO, Mo and ZrO2 matrices have to be completed by post-irradiation examinations on optimized fuel microstructures. On the other hand, a first step in the long term (MA,U)O2-x fuel development process is under investigation with MARIOS and DIAMINO tests in the HFR and OSIRIS, before the implementation of prototypical irradiation tests. For ADS, very informative feedback from inert matrix fuel developments has been completed by dedicated collaborative programmes, including major irradiations for the fuel performance assessment from HELIOS and FUTURIX-FTA experiments, whose post-irradiation examinations are under way. (author)

  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. Application of chemical structure and bonding of actinide oxide materials for forensic science

    Energy Technology Data Exchange (ETDEWEB)

    Wilkerson, Marianne Perry [Los Alamos National Laboratory

    2010-01-01

    We are interested in applying our understanding of actinide chemical structure and bonding to broaden the suite of analytical tools available for nuclear forensic analyses. Uranium- and plutonium-oxide systems form under a variety of conditions, and these chemical species exhibit some of the most complex behavior of metal oxide systems known. No less intriguing is the ability of AnO{sub 2} (An: U, Pu) to form non-stoichiometric species described as AnO{sub 2+x}. Environmental studies have shown the value of utilizing the chemical signatures of these actinide oxide materials to understand transport following release into the environment. Chemical speciation of actinide-oxide samples may also provide clues as to the age, source, or process history of the material. The scientific challenge is to identify, measure and understand those aspects of speciation of actinide analytes that carry information about material origin and history most relevant to forensics. Here, we will describe our efforts in material synthesis and analytical methods development that we will use to provide the fundamental science to characterize actinide oxide molecular structures for forensic science. Structural properties and initial results to measure structural variability of uranium oxide samples using synchrotron-based X-ray Absorption Fine Structure will be discussed.

  5. Minor actinide fission induced by multi-nucleon transfer reaction in inverse kinematics

    Directory of Open Access Journals (Sweden)

    Taieb J.

    2010-03-01

    Full Text Available In the framework of nuclear waste incineration and design of new generation nuclear reactors, experimental data on fission probabilities and on fission fragment yields of minor actinides are crucial to design prototypes. Transfer-induced fission has proven to be an efficient method to study fission probabilities of actinides which cannot be investigated with standard techniques due to their high radioactivity. We report on the preliminary results of an experiment performed at GANIL that investigates fission probabilities with multi-nucleon transfer reactions in inverse kinematics between a 238U beam on a 12C target. Actinides from U to Cm were produced with an excitation energy range from 0 to 30 MeV. In addition, inverse kinematics allowed to characterize the fission fragments in mass and charge. A key point of the analysis resides in the identification of the actinides produced in the different transfer channels. The new annular telescope SPIDER was used to tag the target-like recoil nucleus of the transfer reaction and to determine the excitation energy of the actinide. The fission probability for each transfer channel is accessible and the preliminary results for 238U are promising.

  6. Status of development of actinide blanket processing flowsheets for accelerator transmutation of nuclear waste

    International Nuclear Information System (INIS)

    An accelerator-driven subcritical nuclear system is briefly described that transmutes actinides and selected long-lived fission products. An application of this accelerator transmutation of nuclear waste (ATW) concept to spent fuel from a commercial nuclear power plant is presented as an example. The emphasis here is on a possible aqueous processing flowsheet to separate the actinides and selected long-lived fission products from the remaining fission products within the transmutation system. In the proposed system the actinides circulate through the thermal neutron flux as a slurry of oxide particles in heavy water in two loops with different average residence times: one loop for neptunium and plutonium and one for americium and curium. Material from the Np/Pu loop is processed with a short cooling time (5-10 days) because of the need to keep the total actinide inventory, low for this particular ATW application. The high radiation and thermal load from the irradiated material places severe constraints on the separation processes that can be used. The oxide particles are dissolved in nitric acid and a quarternary, ammonium anion exchanger is used to extract neptunium, plutonium, technetium, and palladium. After further cooling (about 90 days), the Am, Cm and higher actinides are extracted using a TALSPEAK-type process. The proposed operations were chosen because they have been successfully tested for processing high-level radioactive fuels or wastes in gram to kilogram quantities

  7. Plutonium and minor actinide utilisation in a pebble-bed high temperature reactor

    International Nuclear Information System (INIS)

    This paper contains results of the analysis of the pebble-bed high temperature gas-cooled PUMA reactor loaded with plutonium and minor actinide (Pu/MA) fuel. Starting from knowledge and experience gained in the Euratom FP5 projects HTR-N and HTR-N1, this study aims at demonstrating the potential of high temperature reactors to utilize or transmute Pu/MA fuel. The work has been performed within the Euratom FP6 project PUMA. A number of different fuel types and fuel configurations have been analyzed and compared with respect to incineration performance and safety-related reactor parameters. The results show the excellent plutonium and minor actinide burning capabilities of the high temperature reactor. The largest degree of incineration is attained in the case of an HTR fuelled by pure plutonium fuel as it remains critical at very deep burnup of the discharged pebbles. Addition of minor actinides to the fuel leads to decrease of the achievable discharge burnup and therefore smaller fraction of actinides incinerated during reactor operation. The inert-matrix fuel design improves the transmutation performance of the reactor, while the 'wallpaper' fuel does not have advantage over the standard fuel design in this respect. After 100 years of decay following the fuel discharge, the total amount of actinides remains almost unchanged for all of the fuel types considered. Among the plutonium isotopes, only the amount of Pu-241 is reduced significantly due to its relatively short half-life. (authors)

  8. Plutonium and minor actinide utilisation in a pebble-bed high temperature reactor

    Energy Technology Data Exchange (ETDEWEB)

    Petrov, B. Y.; Kuijper, J. C.; Oppe, J.; De Haas, J. B. M. [Nuclear Research and Consultancy Group, Westerduinweg 3, 1755 ZG Petten (Netherlands)

    2012-07-01

    This paper contains results of the analysis of the pebble-bed high temperature gas-cooled PUMA reactor loaded with plutonium and minor actinide (Pu/MA) fuel. Starting from knowledge and experience gained in the Euratom FP5 projects HTR-N and HTR-N1, this study aims at demonstrating the potential of high temperature reactors to utilize or transmute Pu/MA fuel. The work has been performed within the Euratom FP6 project PUMA. A number of different fuel types and fuel configurations have been analyzed and compared with respect to incineration performance and safety-related reactor parameters. The results show the excellent plutonium and minor actinide burning capabilities of the high temperature reactor. The largest degree of incineration is attained in the case of an HTR fuelled by pure plutonium fuel as it remains critical at very deep burnup of the discharged pebbles. Addition of minor actinides to the fuel leads to decrease of the achievable discharge burnup and therefore smaller fraction of actinides incinerated during reactor operation. The inert-matrix fuel design improves the transmutation performance of the reactor, while the 'wallpaper' fuel does not have advantage over the standard fuel design in this respect. After 100 years of decay following the fuel discharge, the total amount of actinides remains almost unchanged for all of the fuel types considered. Among the plutonium isotopes, only the amount of Pu-241 is reduced significantly due to its relatively short half-life. (authors)

  9. Partitioning technologies and actinide science: towards pilot facilities in Europe (ACSEPT project)

    International Nuclear Information System (INIS)

    ACSEPT is an essential contribution to the demonstration, in the long term, of the potential benefits of actinide recycling to minimize the burden on the geological repositories. To succeed, ACSEPT is organized into three technical domains: (i) Considering technically mature aqueous separation processes, ACSEPT works to optimize and select the most promising ones dedicated either to actinide partitioning or to grouped actinide separation. A substantial review was undertaken either to be sure that the right molecule families are being studied, or, on the contrary, to identify new candidates. Results of the first hot tests allowed the validation of some process options. (ii) Concerning pyrochemical separation processes, ACSEPT is focused on the enhancement of the two reference cores of process selected within EUROPART with specific attention to the exhaustive electrolysis in molten chloride (quantitative recovery of the actinides with the lowest amount of fission products) and to actinide back-extraction from an An-Al alloy. R and D efforts are also brought to key scientific and technical issues compulsory for building a complete separation process (head-end steps, salt treatment for recycling and waste management). (iii) By integrating all the experimental results within engineering and systems studies, both in hydro and pyro domains, ACSEPT will deliver relevant flowsheets and recommendations to prepare for future demonstration at a pilot level, in relation with strategies developed through the SNE-TP. In addition, a training and education programme is implemented to share the knowledge among the partitioning community and the future generations of researchers

  10. Research in actinide chemistry. Final report, March 1, 1993--February 28, 1996

    International Nuclear Information System (INIS)

    The present three-year grant period has been a fruitful one for the laboratory as research entered some new areas while continuing in others in which the group has been successful. As in past grant periods, the principal focus has been on complexation of actinide elements with inorganic and organic ligands. The ligands to study have been chosen for their value (known or potential) in actinide separations or for their potential role in environmental behavior of the actinides. Since the radioactivity of some actinides limits the variety of techniques which can be used in their study, we have used open-quotes oxidation state analogsclose quotes. These analogs have the same oxidation state and very similar chemical behavior but are stable or very long-lived. Also, the analogs are chosen for their redox stability to avoid uncertainties in interpretation of systems in which several oxidations may coexist (e.g., in the case of Pu). Examples of such analogs which we have used are: Nd(III), Eu(III) for Pu(III), Am(III), Cm(III); Th(IV) for U(IV), Pu(IV); NpO2+ for PuO2+; UO22+ for NpO22+, PuO22+. These analogs have allowed use of techniques which can increase significantly our understanding of actinide complexation

  11. Research in actinide chemistry. Final report, March 1, 1993--February 28, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Choppin, G R

    1997-01-01

    The present three-year grant period has been a fruitful one for the laboratory as research entered some new areas while continuing in others in which the group has been successful. As in past grant periods, the principal focus has been on complexation of actinide elements with inorganic and organic ligands. The ligands to study have been chosen for their value (known or potential) in actinide separations or for their potential role in environmental behavior of the actinides. Since the radioactivity of some actinides limits the variety of techniques which can be used in their study, we have used {open_quotes}oxidation state analogs{close_quotes}. These analogs have the same oxidation state and very similar chemical behavior but are stable or very long-lived. Also, the analogs are chosen for their redox stability to avoid uncertainties in interpretation of systems in which several oxidations may coexist (e.g., in the case of Pu). Examples of such analogs which we have used are: Nd(III), Eu(III) for Pu(III), Am(III), Cm(III); Th(IV) for U(IV), Pu(IV); NpO{sub 2}{sup +} for PuO{sub 2}{sup +}; UO{sub 2}{sup 2+} for NpO{sub 2}{sup 2+}, PuO{sub 2}{sup 2+}. These analogs have allowed use of techniques which can increase significantly our understanding of actinide complexation.

  12. Application of chemical structure and bonding of actinide oxide materials for forensic science

    International Nuclear Information System (INIS)

    We are interested in applying our understanding of actinide chemical structure and bonding to broaden the suite of analytical tools available for nuclear forensic analyses. Uranium- and plutonium-oxide systems form under a variety of conditions, and these chemical species exhibit some of the most complex behavior of metal oxide systems known. No less intriguing is the ability of AnO2 (An: U, Pu) to form non-stoichiometric species described as AnO2+x. Environmental studies have shown the value of utilizing the chemical signatures of these actinide oxide materials to understand transport following release into the environment. Chemical speciation of actinide-oxide samples may also provide clues as to the age, source, or process history of the material. The scientific challenge is to identify, measure and understand those aspects of speciation of actinide analytes that carry information about material origin and history most relevant to forensics. Here, we will describe our efforts in material synthesis and analytical methods development that we will use to provide the fundamental science to characterize actinide oxide molecular structures for forensic science. Structural properties and initial results to measure structural variability of uranium oxide samples using synchrotron-based X-ray Absorption Fine Structure will be discussed.

  13. Technical requirements for the actinide source-term waste test program

    International Nuclear Information System (INIS)

    This document defines the technical requirements for a test program designed to measure time-dependent concentrations of actinide elements from contact-handled transuranic (CH TRU) waste immersed in brines similar to those found in the underground workings of the Waste Isolation Pilot Plant (WIPP). This test program wig determine the influences of TRU waste constituents on the concentrations of dissolved and suspended actinides relevant to the performance of the WIPP. These influences (which include pH, Eh, complexing agents, sorbent phases, and colloidal particles) can affect solubilities and colloidal mobilization of actinides. The test concept involves fully inundating several TRU waste types with simulated WIPP brines in sealed containers and monitoring the concentrations of actinide species in the leachate as a function of time. The results from this program will be used to test numeric models of actinide concentrations derived from laboratory studies. The model is required for WIPP performance assessment with respect to the Environmental Protection Agency's 40 CFR Part 191B

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

    International Nuclear Information System (INIS)

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

  15. Safe management of actinides in the nuclear fuel cycle: Role of mineralogy

    Science.gov (United States)

    Ewing, Rodney C.

    2011-02-01

    During the past 60 years, more than 1800 metric tonnes of Pu, and substantial quantities of the "minor" actinides, such as Np, Am and Cm, have been generated in nuclear reactors. Some of these transuranium elements can be a source of energy in fission reactions (e.g., 239Pu), a source of fissile material for nuclear weapons (e.g., 239Pu and 237Np), and of environmental concern because of their long-half lives and radiotoxicity (e.g., 239Pu and 237Np). There are two basic strategies for the disposition of these heavy elements: (1) to "burn" or transmute the actinides using nuclear reactors or accelerators; (2) to "sequester" the actinides in chemically durable, radiation-resistant materials that are suitable for geologic disposal. There has been substantial interest in the use of actinide-bearing minerals, especially isometric pyrochlore, A 2B 2O 7 (A = rare earths; B = Ti, Zr, Sn, Hf), for the immobilization of actinides, particularly plutonium, both as inert matrix fuels and nuclear waste forms. Systematic studies of rare-earth pyrochlores have led to the discovery that certain compositions (B = Zr, Hf) are stable to very high doses of alpha-decay event damage. Recent developments in our understanding of the properties of heavy element solids have opened up new possibilities for the design of advanced nuclear fuels and waste forms.

  16. Thermally unstable complexants: Stability of lanthanide/actinide complexes, thermal instability of the ligands, and applications in actinide separations

    Energy Technology Data Exchange (ETDEWEB)

    Nash, K.L.; Rickert, P.G.

    1991-01-01

    Water soluble complexing agents are commonly used in separations to enhance the selectivity of both ion exchange and solvent extraction processes. Applications of this type in the treatment of nuclear wastes using conventional complexing agents have found mixed success due to the nature of the complexants. In addition, the residual solutions containing these species have led to potentially serious complications in waste storage. To overcome some of the limitations of carboxylic acid and aminopolycarboxylate ligands, we have initiated a program to investigate the complexing ability, thermal/oxidative instability, and separation potential of a group of water soluble organophosphorus compounds which we call Thermally Unstable Complexants, or simply TUCS. Complexants of this type appear to be superior to conventional analogues in a number of respects. In this report, we will summarize our research to date on the actinide/lanthanide complexes with a series of substituted methanediphosphonic acids, the kinetics of their oxidative decomposition, and a few applications which have been developed for their use. 17 refs., 5 figs., 3 tab.

  17. Recovery of actinides from TBP-Na2Co3 scrub-waste solutions: the ARALEX process

    International Nuclear Information System (INIS)

    A flowsheet for the recovery of actinides from TBP-Na2CO3 scrub-waste solutions has been developed, based on batch extraction data, and tested, using laboratory-scale countercurrent extraction techniques. The process, called the ARALEX process, uses 2-ethyl-1-hexanol (2-EHOH) to extract the TBP degradation products (HDBP and H2MBP) from acidified Na2CO3 scrub waste leaving the actinides in the aqueous phase. Dibutyl and monobutyl phosphoric acids are attached to the 2-EHOH molecules through hydrogen bonds, which also diminish the ability of the HDBP and H2MBP to complex actinides. Thus all actinides remain in the aqueous raffinate. Dilute sodium hydroxide solutions can be used to back-extract the dibutyl and monobutyl phosphoric acid esters as their sodium salts. The 2-EHOH can then be recycled. After extraction of the acidified carbonate waste with 2-EHOH, the actinides may be readily extracted from the raffinate with DHDECMP or, in the case of tetra- and hexavalent actinides, with TBP. The ARALEX process can also be applied to other actinide waste streams which contain appreciable concentrations of polar organic compounds (e.g., detergents) that interfere with conventional actinide ion exchange and liquid-liquid extraction procedures. 20 figures, 6 tables

  18. Recovery of actinides from TBP-Na/sub 2/Co/sub 3/ scrub-waste solutions: the ARALEX process

    Energy Technology Data Exchange (ETDEWEB)

    Horwitz, E.P.; Bloomquist, C.A.A.; Mason, G.W.; Leonard, R.A.; Ziegler, A.A.

    1979-08-01

    A flowsheet for the recovery of actinides from TBP-Na/sub 2/CO/sub 3/ scrub-waste solutions has been developed, based on batch extraction data, and tested, using laboratory-scale countercurrent extraction techniques. The process, called the ARALEX process, uses 2-ethyl-1-hexanol (2-EHOH) to extract the TBP degradation products (HDBP and H/sub 2/MBP) from acidified Na/sub 2/CO/sub 3/ scrub waste leaving the actinides in the aqueous phase. Dibutyl and monobutyl phosphoric acids are attached to the 2-EHOH molecules through hydrogen bonds, which also diminish the ability of the HDBP and H/sub 2/MBP to complex actinides. Thus all actinides remain in the aqueous raffinate. Dilute sodium hydroxide solutions can be used to back-extract the dibutyl and monobutyl phosphoric acid esters as their sodium salts. The 2-EHOH can then be recycled. After extraction of the acidified carbonate waste with 2-EHOH, the actinides may be readily extracted from the raffinate with DHDECMP or, in the case of tetra- and hexavalent actinides, with TBP. The ARALEX process can also be applied to other actinide waste streams which contain appreciable concentrations of polar organic compounds (e.g., detergents) that interfere with conventional actinide ion exchange and liquid-liquid extraction procedures. 20 figures, 6 tables.

  19. ACTINIDE REMOVAL PROCESS SAMPLE ANALYSIS, CHEMICAL MODELING, AND FILTRATION EVALUATION

    Energy Technology Data Exchange (ETDEWEB)

    Martino, C.; Herman, D.; Pike, J.; Peters, T.

    2014-06-05

    Filtration within the Actinide Removal Process (ARP) currently limits the throughput in interim salt processing at the Savannah River Site. In this process, batches of salt solution with Monosodium Titanate (MST) sorbent are concentrated by crossflow filtration. The filtrate is subsequently processed to remove cesium in the Modular Caustic Side Solvent Extraction Unit (MCU) followed by disposal in saltstone grout. The concentrated MST slurry is washed and sent to the Defense Waste Processing Facility (DWPF) for vitrification. During recent ARP processing, there has been a degradation of filter performance manifested as the inability to maintain high filtrate flux throughout a multi-batch cycle. The objectives of this effort were to characterize the feed streams, to determine if solids (in addition to MST) are precipitating and causing the degraded performance of the filters, and to assess the particle size and rheological data to address potential filtration impacts. Equilibrium modelling with OLI Analyzer{sup TM} and OLI ESP{sup TM} was performed to determine chemical components at risk of precipitation and to simulate the ARP process. The performance of ARP filtration was evaluated to review potential causes of the observed filter behavior. Task activities for this study included extensive physical and chemical analysis of samples from the Late Wash Pump Tank (LWPT) and the Late Wash Hold Tank (LWHT) within ARP as well as samples of the tank farm feed from Tank 49H. The samples from the LWPT and LWHT were obtained from several stages of processing of Salt Batch 6D, Cycle 6, Batch 16.

  20. Actinide partitioning and recovery of valuables from HLW

    International Nuclear Information System (INIS)

    The Indian nuclear power programme is sustained by adoption of a closed fuel cycle where in the fissile and fertile materials are recycled by reprocessing of spent fuel. The reprocessing step leads to the generation of high level waste which is presently vitrified using borosilicate matrices. With the nuclear power profile on the brink of an exponential increase, it becomes imperative to consider and adopt cross-cut technologies that would not only lead to a substantial reduction in repository capacity both in terms of volumes and thermal loads but also lead to a reduction in radiotoxicity of the waste forms. Partitioning of high level waste (HLW) is the first step towards achieving the above objectives. Developmental efforts in the last decade have placed partitioning of high level waste in the realms of practical application. This paper will present a compilation of various R and D efforts on development of processes and technologies under consideration for partitioning of high level waste in the Indian context. While numerous laboratory trials are being pursued, some of them which have matured for plant scale demonstration are related to partitioning of actinides from acidic high level waste and recovery of cesium and strontium from high level waste. A structured R and D framework has been worked out to develop deployable processes and technologies for their demonstration on engineering scale. One of the most defining step in this work is selection of potentially successful extraction system based on the systematic study on the extraction properties and their optimization for full scale studies. (author)

  1. Determination of long-lived actinides in soil leachates by inductively coupled plasma: Mass spectrometry

    International Nuclear Information System (INIS)

    Inductively coupled plasma -- mass spectrometry (ICP-MS) was used to concurrently determine multiple long-lived (t1/2 > 104 y) actinide isotopes in soil samples. Ultrasonic nebulization was found to maximize instrument sensitivity. Instrument detection limits for actinides in solution ranged from 50 mBq L-1 (239Pu) to 2 μBq L-1 (235U) Hydride adducts of 232Th and 238U interfered with the determinations of 233U and 239 Pu; thus, extraction chromatography was, used to eliminate the sample matrix, concentrate the analytes, and separate uranium from the other actinides. Alpha spectrometric determinations of 230Th, 239Pu, and the 234U/238U activity ratio in soil leachates compared well with ICP-MS determinations; however, there were some small systematic differences (ca. 10%) between ICP-MS and a-spectrometric determinations of 234U and 238U activities

  2. Response of actinides to flux changes in high-flux systems

    International Nuclear Information System (INIS)

    When discussing the transmutation of actinides in accelerator-based transmutation of waste (ATW) systems, there has been some concern about the dynamics of the actinides under high transient fluxes. For a pure neptunium feed, it has been estimated that the 238Np/237Np ratio increase due to an increasing flux may lead to an unstable, positive reactivity growth. In this analysis, a perturbation method is used to calculate the response of the entire set of actinides in a general way that allows for more species than just neptunium. The time response of the system can be calculated; i.e., a plot of fuel composition and reactivity versus time after a change in flux can be made. The effects of fission products can also be included. The procedure is extremely accurate on short time scales (∼ 1000 s) for the flux levels we contemplate. Calculational results indicate that the reactivity insertions are always smaller than previously estimated

  3. The uncertainty analysis of a liquid metal reactor for burning minor actinides from light water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hang Bok [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1998-12-31

    The neutronics analysis of a liquid metal reactor for burning minor actinides has shown that uncertainties in the nuclear data of several key minor actinide isotopes can introduce large uncertainties in the predicted performance of the core. A comprehensive sensitivity and uncertainty analysis was performed on a 1200 MWth actinide burner designed for a low burnup reactivity swing, negative doppler coefficient, and low sodium void worth. Sensitivities were generated using depletion perturbation methods for the equilibrium cycle of the reactor and covariance data was taken ENDF-B/V and other published sources. The relative uncertainties in the burnup swing, doppler coefficient, and void worth were conservatively estimated to be 180%, 97%, and 46%, respectively. 5 refs., 1 fig., 3 tabs. (Author)

  4. Updated multi-group cross sections of minor actinides with improved resonance treatment

    International Nuclear Information System (INIS)

    The study of minor actinide in transmutation reactors and other future applications makes resonance self-shielding treatment a significant issue for criticality and isotope depletion. Resonance treatment for minor actinides has been carried out by subgroup method with improved interference effect through interference correction. Subgroup data was generated using RMET21 and GENP codes along with multi-group cross section data by NJOY nuclear data processing system. Updated multi-group cross section data library for a neutron transport code nTRACER was compared with solutions from MCNPX. The resonance interaction of uranium with minor actinides has been included by modified interference treatment of interference correction in subgroup methodology. The comparison of cross sections and multiplication factor in pin and assembly problems showed significant improvement from systematic resonance treatment especially for 237Np and 243Am. (author)

  5. Emergence of californium as the second transitional element in the actinide series.

    Science.gov (United States)

    Cary, Samantha K; Vasiliu, Monica; Baumbach, Ryan E; Stritzinger, Jared T; Green, Thomas D; Diefenbach, Kariem; Cross, Justin N; Knappenberger, Kenneth L; Liu, Guokui; Silver, Mark A; DePrince, A Eugene; Polinski, Matthew J; Van Cleve, Shelley M; House, Jane H; Kikugawa, Naoki; Gallagher, Andrew; Arico, Alexandra A; Dixon, David A; Albrecht-Schmitt, Thomas E

    2015-01-01

    A break in periodicity occurs in the actinide series between plutonium and americium as the result of the localization of 5f electrons. The subsequent chemistry of later actinides is thought to closely parallel lanthanides in that bonding is expected to be ionic and complexation should not substantially alter the electronic structure of the metal ions. Here we demonstrate that ligation of californium(III) by a pyridine derivative results in significant deviations in the properties of the resultant complex with respect to that predicted for the free ion. We expand on this by characterizing the americium and curium analogues for comparison, and show that these pronounced effects result from a second transition in periodicity in the actinide series that occurs, in part, because of the stabilization of the divalent oxidation state. The metastability of californium(II) is responsible for many of the unusual properties of californium including the green photoluminescence. PMID:25880116

  6. Strontium and Actinide Separations from High Level Nuclear Waste Solutions using Monosodium Titanate - Actual Waste Testing

    Energy Technology Data Exchange (ETDEWEB)

    Peters, T.B.; Barnes, M.J.; Hobbs,D.T.; Walker, D.D.; Fondeur, F.F.; Norato, M.A.; Pulmano, R.L.; Fink, S.D.

    2005-11-01

    Pretreatment processes at the Savannah River Site will separate {sup 90}Sr, alpha-emitting and radionuclides (i.e., actinides) and {sup 137}Cs prior to disposal of the high-level nuclear waste. Separation of {sup 90}Sr and alpha-emitting radionuclides occurs by ion exchange/adsorption using an inorganic material, monosodium titanate (MST). Previously reported testing with simulants indicates that the MST exhibits high selectivity for strontium and actinides in high ionic strength and strongly alkaline salt solutions. This paper provides a summary of data acquired to measure the performance of MST to remove strontium and actinides from actual waste solutions. These tests evaluated the effects of ionic strength, mixing, elevated alpha activities, and multiple contacts of the waste with MST. Tests also provided confirmation that MST performs well at much larger laboratory scales (300-700 times larger) and exhibits little affinity for desorption of strontium and plutonium during washing.

  7. Engineering assessment studies on the JRC's actinides partitioning processes for transmutation

    International Nuclear Information System (INIS)

    Three conceptual processes have been studied and investigated for the feasibility of removing actinides from high active waste. Two of the flowsheets rely completely on counter current techniques for the actinides separation namely the TBP and HDEHP processes, whereas the third process OXAL, uses a precipitation technique in the first instance followed by dissolution of the actinides and rare-earths (RE) for further treatment using a modified HDEHP process. Many important factors such as 'direct' or 'delayed', concentrated or unconcentrated HAW, storage time, activity and heat release levels, solvent irradiation DF's, safety and steady-state recycling conditions for U-LWR, Pu-LWR and FBRs for possible transmutation scenarios have been taken into consideration

  8. Standard practice for alternate actinide calibration for inductively coupled plasma-mass spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2004-01-01

    1.1 This practice provides guidance for an alternate linear calibration for the determination of selected actinide isotopes in appropriately prepared aqueous solutions by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). This alternate calibration is mass bias adjusted using thorium-232 (232Th) and uranium-238 (238U) standards. One of the benefits of this standard practice is the ability to calibrate for the analysis of highly radioactive actinides using calibration standards at much lower specific activities. Environmental laboratories may find this standard practice useful if facilities are not available to handle the highly radioactive standards of the individual actinides of interest. 1.2 The instrument response for a series of determinations of known concentration of 232Th and 238U defines the mass versus response relationship. For each standard concentration, the slope of the line defined by 232Th and 238U is used to derive linear calibration curves for each mass of interest using interference equ...

  9. Phosphonates as alternative to tributyl phosphate for the separation of actinides from fission products

    Energy Technology Data Exchange (ETDEWEB)

    Vyas, Chirag K.; Joshirao, Pranav M.; Manchanda, Vijay K. [Sungkyunkwan Univ., Suwon (Korea, Republic of). Dept. of Energy Science; Rao, C.V.S. Brahmmananda; Jayalakshmi, S. [Indira Gandhi Centre for Atomic Research, Kalpakkam (India). Fuel Chemistry Div.

    2015-06-01

    The present work investigates the role of increase in the basicity of organophosphorus extractant (dialkylalkyl phosphonates) on the uptake of actinides and fission products vis-a-vis tributyl phosphate (TBP), currently employed as a universal extractant. Two dialkylalkyl phosphonates viz. dibutylpropyl phosphonate (DBPrP) and dibutylpentyl phosphonate (DBPeP) were synthesized, characterized and evaluated for their solvent extraction behavior towards U(VI), Th(IV), Eu(III) and Tc(VII) in nitric acid medium ranging from 0.01-6 M. It was observed that increasing the basicity of the phosphoryl oxygen enhanced the uptake of the actinides and the distribution coefficient values were significantly larger as compared to TBP. The limiting organic concentration (LOC) value was estimated for Th(IV) for these extractants and compared with the TBP system. The separation factors of actinides with phosphonates over Tc(VII) are distinctly better than that with TBP.

  10. Experimental and calculational analyses of actinide samples irradiated in EBR-II

    International Nuclear Information System (INIS)

    Higher actinides influence the characteristics of spent and recycled fuel and dominate the long-term hazards of the reactor waste. Reactor irradiation experiments provide useful benchmarks for testing the evaluated nuclear data for these actinides. During 1967 to 1970, several actinide samples were irradiated in the Idaho EBR-II fast reactor. These samples have now been analyzed, employing mass and alpha spectrometry, to determine the heavy element products. A simple spherical model for the EBR-II core and a recent version of the ORIGEN code with ENDF/B-V data were employed to calculate the exposure products. A detailed comparison between the experimental and calculated results has been made. For samples irradiated at locations near the core center, agreement within 10% was obtained for the major isotopes and their first daughters, and within 20% for the nuclides up the chain. A sensitivity analysis showed that the assumed flux should be increased by 10%

  11. Ultra-trace analytical techniques for internal dosimetry of actinides: an appraisal

    International Nuclear Information System (INIS)

    This paper briefly reviews and summarises the currently available analytical techniques employed in internal dosimetry for the determination of important actinides 232Th, 238U and 239,240Pu in bio-assay samples. The techniques covered are neutron activation analysis (NAA), delayed neutron activation analysis (DNAA), alpha spectrometry, spectrophotometry, fluorimetry, kinetic phosphorescence, solid state nuclear track detector (SSNTD), fission track analysis (FTA), inductively coupled plasma-mass spectrometry (ICP-MS) and anodic/adsorptive striping voltametry (ASV). A comparison is made for the detection limits of various techniques for individual actinides in terms of the fraction/multiple of the derived urinary excretion levels such as DRL and DIL. Advantages and limitations of each technique have been discussed and conclusions regarding the most suitable technique for each actinide are reported. (author). 20 refs., 3 tabs

  12. Pyrochlore as nuclear waste form. Actinide uptake and chemical stability

    Energy Technology Data Exchange (ETDEWEB)

    Finkeldei, Sarah Charlotte

    2015-07-01

    Radioactive waste is generated by many different technical and scientific applications. For the past decades, different waste disposal strategies have been considered. Several questions on the waste disposal strategy remain unanswered, particularly regarding the long-term radiotoxicity of minor actinides (Am, Cm, Np), plutonium and uranium. These radionuclides mainly arise from high level nuclear waste (HLW), specific waste streams or dismantled nuclear weapons. Although many countries have opted for the direct disposal of spent fuel, from a scientific and technical point of view it is imperative to pursue alternative waste management strategies. Apart from the vitrification, especially for trivalent actinides and Pu, crystalline ceramic waste forms are considered. In contrast to glasses, crystalline waste forms, which are chemically and physically highly stable, allow the retention of radionuclides on well-defined lattice positions within the crystal structure. Besides polyphase ceramics such as SYNROC, single phase ceramics are considered as tailor made host phases to embed a specific radionuclide or a specific group. Among oxidic single phase ceramics pyrochlores are known to have a high potential for this application. This work examines ZrO{sub 2} based pyrochlores as potential nuclear waste forms, which are known to show a high aqueous stability and a high tolerance towards radiation damage. This work contributes to (1) understand the phase stability field of pyrochlore and consequences of non-stoichiometry which leads to pyrochlores with mixed cationic sites. Mixed cationic occupancies are likely to occur in actinide-bearing pyrochlores. (2) The structural uptake of radionuclides themselves was studied. (3) The chemical stability and the effect of phase transition from pyrochlore to defect fluorite were probed. This phase transition is important, as it is the result of radiation damage in ZrO{sub 2} based pyrochlores. ZrO{sub 2} - Nd{sub 2}O{sub 3} pellets

  13. International Workshop on Orbital and Spin Magnetism of Actinides (IWOSMA-3)

    Energy Technology Data Exchange (ETDEWEB)

    Temmerman, W; Tobin, J; der Laan, G v

    2006-11-08

    This International Workshop on Orbital and Spin Magnetism of Actinides (IWOSMA) is the third in a series. The first workshop took place in Daresbury in 1999 and the second in Berkeley, CA, USA in 2002. These workshops are informal gatherings of theoreticians and experimentalists addressing the latest issues in the electronic and magnetic properties of actinides. The magnetism of transition metal systems and lanthanide systems is now fairly well understood, where d and f electrons can be described in a delocalized and localized model, respectively. On the other hand, actinide systems do not fit in such a description. The localization of the 5f is in between that of the 3d and 4f and the strong spin-orbit interaction necessitates a relativistic approach. Furthermore, electron correlation effects play a major role in these compounds. Recently, it has become possible to determine element-specific magnetic moments using neutron diffraction and x-ray scattering and absorption. The latter technique makes it even possible to separate the orbital and spin contribution to the total magnetic moment. The results are very interesting but difficult to reproduce with present state-of-art calculations. Not only a very large orbital polarization but also a large magnetic dipole term has been measured in cubic compounds, such as US. This allows for severe testing of the extra terms included in band theory to account for orbital polarization. It is also clear that deeper insight in magnetism can be obtained by studying the unusual behavior of the actinides. The recent development and application of such techniques as DMFT could contribute to the understanding of magnetism in actinides. Despite the fact that actinides for health reasons will find less application in technological market products, the understanding of their magnetic and electronic properties will no doubt provide key elements for a general description of electron correlation and relativistic effects.

  14. Possibilities to optimize sodium cooled fast reactors with respect to Actinide burning

    International Nuclear Information System (INIS)

    The optimization of fast reactor cores with respect to the destruction of Minor Actinides starts from the question, whether the neutron spectrum can be hardened by changing the core geometry, core size or fuel type. Spectrum hardening would increase the destruction (fission) of actinides compared to their further production due to capture processes. Reference point of this study is the European Fast Reactor EFR. It is shown that a flat core geometry with metal fuel would offer an optimum and that small power units, i. e. smaller cores are most favourable

  15. Vaporisation of candidate nuclear fuels and targets for transmutation of minor actinides

    Energy Technology Data Exchange (ETDEWEB)

    Gotcu-Freis, P., E-mail: p.gotcu@tudelft.nl [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, 76125 Karlsruhe (Germany); Delft University of Technology, Faculty of Applied Sciences, Mekelweg 15, 2629 JB Delft (Netherlands); Hiernaut, J.-P. [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, 76125 Karlsruhe (Germany); Colle, J.-Y., E-mail: jean-yves.colle@ec.europa.eu [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, 76125 Karlsruhe (Germany); Naestren, C.; Carretero, A. Fernandez; Konings, R.J.M. [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, 76125 Karlsruhe (Germany)

    2011-04-15

    The thermal stability and high temperature behaviour of candidate fuels and targets for transmutation of minor actinides has been investigated. Zirconia-based solid solution, MgO-based CERCER and molybdenum-based CERMET fuels containing Am and/or Pu in various concentrations were heated up to 2700 K in a Knudsen cell coupled with a quadrupole mass spectrometer, to measure their vapour pressure and vapour composition. The results reveal that the vaporisation of the actinides from the samples is not only determined by the thermodynamics of the system but is also related to the dynamic evolution of multi-component mixtures with complex composition or microstructure.

  16. Numerical analysis on reduction of radioactive actinides by recycling of nuclear fuel

    International Nuclear Information System (INIS)

    Worldwide, human growth has reached unparalleled levels historically, this implies a need for more energy, and just in 2007 was consumed in the USA 4157 x 109 kWh of electricity and there were 6 x 109 metric tons of carbon dioxide, which causes a devastating effect on our environment. To this problem, a solution to the demand for non-fossil energy is nuclear energy, which is one of the least polluting and the cheapest among non-fossil energy; however, a problem remains unresolved the waste generation of nuclear fuels. In this work the option of a possible transmutation of actinides in a nuclear reactor of BWR was analyzed, an example of this are the nuclear reactors at the Laguna Verde nuclear power plant, which have generated spent fuel stored in pools awaiting a decision for final disposal or any other existing alternative. Assuming that the spent fuel was reprocessed to separate useful materials and actinides such as plutonium and uranium remaining, could take these actinides and to recycle them inside the same reactor that produced them, so il will be reduced the radiotoxicity of spent fuel. The main idea of this paper is to evaluate by means of numeric simulation (using the Core Management System (CMS)) the reduction of minor actinides in the case of being recycled in fresh fuel of the type BWR. The actinides were introduced hypothetically in the fuel pellets to 6% by weight, and then use a burned in the range of 0-65 G Wd/Tm, in order to have a better panorama of their behavior and thus know which it is the best choice for maximum reduction of actinides. Several cases were studied, that is to say were used as fuels; the UO2 and MOX. Six different cases were also studied to see the behavior of actinides in different situations. The CMS platform calculation was used for the analysis of the cases presented. Favorable results were obtained, having decreased from a range of 35% to 65% of minor actinides initially introduced in the fuel rods, reducing the

  17. Optical spectra and electronic structure of actinide ions in compounds and in solution

    International Nuclear Information System (INIS)

    This report provides a summary of theoretical and experimental studies of actinide spectra in condensed phases. Much of the work was accomplished at Argonne National Laboratory, but references to related investigations by others are included. Spectroscopic studies of the trivlent actinides are emphasized, as is the use of energy level parameters, evaluated from experimental data, to investigate systematic trends in electronic structure and other properties. Some reference is made to correlations with atomic spectra, as well as with spectra of the (II), (IV), and higher valence states. 207 refs., 39 figs., 38 tabs

  18. Hydration properties and ionic radii of actinide(III) ions in aqueous solution

    International Nuclear Information System (INIS)

    Ionic radii of actinide(III) cations (from U(III) to Cf(III)) in aqueous solution have been derived for the first time starting from accurate experimental determination of the ion-water distances obtained by combining extended X-ray absorption fine structure (EXAFS) results and molecular dynamics (MD) structural data. A strong analogy has been found between the lanthanide and actinide series concerning hydration properties. The existence of a contraction of the An-O distance along the series has been highlighted, while no decrease of the hydration number is evident up to Cf(III). (authors)

  19. Fuels and targets for incineration and transmutation of actinides: the ITU programme

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, A.; Glatz, J.P.; Haas, D.; Konings, R.J.M.; Somers, J.; Toscano, E.; Walker, C.T.; Wegen, D. [Eurpean Commission, Joint Research Centre, Institute for Transuranium Elements, Kurlsruhe (Germany)

    2000-07-01

    The ITU programme for the development of fuels and targets for transmutation of actinides is presented. The fabrication of various types of oxide fuels/targets by dust-free processes is described. Selected results of post-irradiation examinations of irradiation experiments (SUPERFACT, TRABANT-1, EFTTRA-T4) are presented to demonstrate the irradiation behaviour of these fuels/targets. Finally, the future developments at ITU in this field are described, including the new shielded facility (the MA lab) for fabrication of minor actinide fuels. (authors)

  20. Study on burn-up credit and minor actinide in post-irradiation analysis

    International Nuclear Information System (INIS)

    Accuracy of burnup calculation for actinide is very important as to the study of burn-up credit. For minor-actinides such as Am243 and Cm244, however, typical burnup calculation codes are not accurate enough. The accuracy for both nuclides was studied by using the SWAT code. The study showed that the C/E values of both nuclides could be improved at the same time by changing the cross section of Pu242. A study of burnup calculation related to the cross section of Pu242 should be performed to improve the accuracy for both nuclides. (author)

  1. The behaviour of selected fission products and actinides on UTEVA® resin

    International Nuclear Information System (INIS)

    The behaviour of selected fission product elements and actinides on UTEVA® resin in HCl and HNO3 media was determined by loading a mixed solution of Sr, Y, Zr, Mo, Ag, Cd, Cs, Ba, Ce, Eu, Tb, U, Np and Pu on to UTEVA® resin. The columns were eluted with decreasing concentrations of each acid. This investigation used stable elemental standards for the fission product elements and radioactive tracers for the actinide elements. The eluted fractions were analysed using ICP-OES and ICP-MS to determine the recovery of the elements across the fractions. A comparison using valency adjustment for the separation of Pu and Np is also reported. (author)

  2. Problems facing the study of actinide samples by ICAP-OES

    International Nuclear Information System (INIS)

    For the study of actinide-containing substances an ICP-stand (inductively-coupled plasma; ICAP-OES=inductively coupled argon plasma-optical emission spectrography) was built into a glove box. A device for alternate use of a 'normal' stand and an ICP-stand with the same spectrograph is described. Special problems arising in the analysis of actinide samples (specific activity, sample size, cost) are discussed. The limits of detection of the impurities occurring most frequently in uranium, plutonium, and americium matrices are compared with their pure solutions. (orig.)

  3. Vaporisation of candidate nuclear fuels and targets for transmutation of minor actinides

    International Nuclear Information System (INIS)

    The thermal stability and high temperature behaviour of candidate fuels and targets for transmutation of minor actinides has been investigated. Zirconia-based solid solution, MgO-based CERCER and molybdenum-based CERMET fuels containing Am and/or Pu in various concentrations were heated up to 2700 K in a Knudsen cell coupled with a quadrupole mass spectrometer, to measure their vapour pressure and vapour composition. The results reveal that the vaporisation of the actinides from the samples is not only determined by the thermodynamics of the system but is also related to the dynamic evolution of multi-component mixtures with complex composition or microstructure.

  4. Actinide Sorption in a Brine/Dolomite Rock System: Evaluating the Degree of Conservatism in Kd Ranges used in Performance Assessment Modeling for the WIPP Nuclear Waste Repository

    Science.gov (United States)

    Dittrich, T. M.; Reed, D. T.

    2015-12-01

    The Waste Isolation Pilot Plant (WIPP) near Carlsbad, NM is the only operating nuclear waste repository in the US and has been accepting transuranic (TRU) waste since 1999. The WIPP is located in a salt deposit approximately 650 m below the surface and performance assessment (PA) modeling for a 10,000 year period is required to recertify the operating license with the US EPA every five years. The main pathway of concern for environmental release of radioactivity is a human intrusion caused by drilling into a pressurized brine reservoir below the repository. This could result in the flooding of the repository and subsequent transport in the high transmissivity layer (dolomite-rich Culebra formation) above the waste disposal rooms. We evaluate the degree of conservatism in the estimated sorption partition coefficients (Kds) ranges used in the PA based on an approach developed with granite rock and actinides (Dittrich and Reimus, 2015; Dittrich et al., 2015). Sorption onto the waste storage material (Fe drums) may also play a role in mobile actinide concentrations. We will present (1) a conceptual overview of how Kds are used in the PA model, (2) technical background of the evolution of the ranges and (3) results from batch and column experiments and model predictions for Kds with WIPP dolomite and clays, brine with various actinides, and ligands (e.g., acetate, citrate, EDTA) that could promote transport. The current Kd ranges used in performance models are based on oxidation state and are 5-400, 0.5-10,000, 0.03-200, and 0.03-20 mL g-1 for elements with oxidation states of III, IV, V, and VI, respectively. Based on redox conditions predicted in the brines, possible actinide species include Pu(III), Pu(IV), U(IV), U(VI), Np(IV), Np(V), Am(III), and Th(IV). We will also discuss the challenges of upscaling from lab experiments to field scale predictions, the role of colloids, and the effect of engineered barrier materials (e.g., MgO) on transport conditions. Dittrich

  5. The seventh international conference on the chemistry and migration behavior of actinides and fission products in the Geosphere MIGRATION'99 abstracts

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, C

    1999-09-01

    The Migration conferences focus on recent developments in the fundamental chemistry of actinides and fission products in natural aquifer systems, their interactions and migration in the geosphere, and the processes involved in modeling their geochemical behavior. The primary mode dissemination of technical information will be early evening poster sessions designed to encourage intensive communication between the authors and participants. Daily oral sessions will be opened with invited lectures followed by contributed papers within the scope of each session. Sessions cover: (A) Chemistry of actinides and fission products in natural aquatic systems: (1) Solubilities and dissolution reactions; (2) Complexation with inorganic and organic ligands; (3) Redox reactions; (4) Colloid formation; and (5) Experimental methods. (B) Geochemical interactions and transport phenomena: (1) Diffusion and migration in geologic media; (2) Sorption/desorption phenomena; (3) Natural analog studies; (4) Effects of biological activities and organic materials; (5) Colloid transport; (6) Radionuclides in soils; and (7) Soil-remediation chemistries. (C) Data base development and modeling: (1) Data selection and evaluation; (2) Data base management; (3) Geochemical models and modeling; (4) Application of models; and (5) Validation of modeling results.

  6. A contribution to the study of the extraction of mineral acids and of actinide (IV) and (VI) cations by N,N-dialkylamides

    International Nuclear Information System (INIS)

    N,N-dialkylamides are alternate extractants to tributylphosphate, TBP, for the actinides separation in nuclear fuel reprocessing. N,N-di (2-ethyl hexyl) butyramide and N,N-di (2 ethyl hexyl) isobutyramide are selected for their sufficient extraction and partition ability towards actinides (IV) and (VI) without coextracting fission products. Mechanisms of HNO3, UO22+, Pu4+, Th4+ are investigated. Nitric acid extraction is due to the competitive formation of the species (HNO3)L2, (HNO3)L, (HNO3)2L (L: DOBA or DOiBA). An hydrogen bond is the driving force of the transfer. For low acidity media, amides are neutral extractants. Physical interactions, between free ligand and metallic complex, arise for high amide concentrations. Taking into account the non-ideality of the organic medium by a hard spheres mixture model, we estimate that such interactions are far from negligible and very specific to the amide group. Unlike TBP, when increasing acidity, amides behave as anionic extractants. DOBA and DOiBA appear to be satisfactory extractants for fuel reprocessing

  7. Mechanical behaviour and diffusion of gas during neutron irradiation of actinides in ceramic inert matrices

    NARCIS (Netherlands)

    Neeft, E.A.C.

    2004-01-01

    Fission of actinides from nuclear waste in inert matrices (materials without uranium) can reduce the period in time that nuclear waste is more radiotoxic than uranium ore that is the rock from which ordinary reactor fuel is made. A pioneering study is performed with the inert matrices: MgO, MgAl2O4,

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

    International Nuclear Information System (INIS)

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

  9. 44th Journées des Actinides and 10th SPCA. Scientific Programme and Abstracts

    International Nuclear Information System (INIS)

    In the opening Session for the 10th SPCA the program of the school will be presented.The sessions of the 10th SPCA are: Physics, Chemistry,Theory, electronic structure,Nuclear forensics, Measuring systems. While the 10th SPCA lectures on crystallography, Physics, Chemistry and basics of actinides research

  10. Speciation of actinides in aqueous solution by time-resolved laser-induced fluorescence spectroscopy (TRLFS)

    International Nuclear Information System (INIS)

    Time-resolved laser-induced fluorescence spectroscopy (TRLFS) as a sensitive and selective method has been applied to the speciation of actinides in aqueous solution. Studies on hydrolysis and carbonate complexation of U(VI) and on determination of hydration number of Cm(III) are reported. (author)

  11. Sorption Speciation of Lanthanides/Actinides on Minerals by TRLFS, EXAFS and DFT Studies: A Review

    Directory of Open Access Journals (Sweden)

    Xiaoli Tan

    2010-11-01

    Full Text Available Lanthanides/actinides sorption speciation on minerals and oxides by means of time resolved laser fluorescence spectroscopy (TRLFS, extended X-ray absorption fine structure spectroscopy (EXAFS and density functional theory (DFT is reviewed in the field of nuclear disposal safety research. The theoretical aspects of the methods are concisely presented. Examples of recent research results of lanthanide/actinide speciation and local atomic structures using TRLFS, EXAFS and DFT are discussed. The interaction of lanthanides/actinides with oxides and minerals as well as their uptake are also of common interest in radionuclide chemistry. Especially the sorption and inclusion of radionuclides into several minerals lead to an improvement in knowledge of minor components in solids. In the solid-liquid interface, the speciation and local atomic structures of Eu(III, Cm(III, U(VI, and Np(IV/VI in several natural and synthetic minerals and oxides are also reviewed and discussed. The review is important to understand the physicochemical behavior of lanthanides/actinides at a molecular level in the natural environment.

  12. Overall assessment of actinide partitioning and transmutation for waste management purposes

    International Nuclear Information System (INIS)

    A program to establish the technical feasibility and incentives for partitioning (i.e., recovering) actinides from fuel cycle wastes and then transmuting them in power reactors to shorter-lived or stable nuclides has recently been concluded at the Oak Ridge National Laboratory. The feasibility was established by experimentally investigating the reduction that can be practicably achieved in the actinide content of the wastes sent to a geologic repository, and the incentives for implementing this concept were defined by determining the incremental costs, risks, and benefits. Eight US Department of Energy laboratories and three private companies participated in the program over its 3-year duration. A reference fuel cycle was chosen based on a self-generated plutonium recycle PWR, and chemical flowsheets based on solvent extraction and ion-exchange techniques were generated that have the potential to reduce actinides in fuel fabrication and reprocessing plant wastes to less than 0.25% of those in the spent fuel. Waste treatment facilities utilizing these flowsheets were designed conceptually, and their costs were estimated. Finally, the short-term (contemporary) risks from fuel cycle operations and long-term (future) risks from deep geologic disposal of the wastes were estimated for cases with and without partitioning and transmutation. It was concluded that, while both actinide partitioning from wastes and transmutation in power reactors appear to be feasible using currently identified and studied technology, implementation of this concept cannot be justified because of the small long-term benefits and substantially increased costs of the concept

  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 a...

  14. The Efficacy of Denaturing Actinide Elements as a Means of Decreasing Materials Attractiveness

    Energy Technology Data Exchange (ETDEWEB)

    Hase, Kevin R.; Ebbinghaus, Bartley B.; Sleaford, Brad W.; Robel, Martin; Collins, Brian A.; Prichard, Andrew W.

    2013-07-01

    This paper is an extension to earlier studies that examined the attractiveness of materials mixtures containing special nuclear materials (SNM) and alternate nuclear materials (ANM). This study considers the concept of denaturing as applied to the actinide elements present in spent fuel as a means to reduce materials attractiveness. Highly attractive materials generally have low values of bare critical mass, heat content, and dose.

  15. Gender-specific differences in the biokinetics of plutonium and other actinides

    International Nuclear Information System (INIS)

    The published data on the biokinetics of actinide distribution and retention in humans and animals have been reviewed. It is concluded that in humans there are strong indications that urinary and faecal excretion of plutonium is greater in females than males. Animal data indicate that this may also be true for americium, neptunium and uranium. (author)

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

    International Nuclear Information System (INIS)

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

  17. Performance comparison of metallic, actinide burning fuel in lead-bismuth and sodium cooled fast reactors

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, K.D.; Herring, J.S.; Macdonald, P.E. [Idaho National Engineering and Environment Lab., Advanced Nuclear Energy, Idaho (United States)

    2001-07-01

    Various methods have been proposed to ''incinerate'' or ''transmute'' the current inventory of transuranic waste (TRU) that exits in spent light-water-reactor (LWR) fuel, and weapons plutonium. These methods include both critical (e.g., fast reactors) and non-critical (e.g., accelerator transmutation) systems. The work discussed here is part of a larger effort at the Idaho National Engineering and Environmental Laboratory (INEEL) and at the Massachusetts Institute of Technology (MIT) to investigate the suitability of lead and lead-alloy cooled fast reactors for producing low-cost electricity as well as for actinide burning. The neutronics of non fertile fuel loaded with 20 or 30-wt% light water reactor (LWR) plutonium plus minor actinides for use in a lead-bismuth cooled fast reactor are discussed in this paper, with an emphasis on the fuel cycle life and isotopic content. Calculations show that the average actinide burn rate is similar for both the sodium and lead-bismuth cooled cases ranging from -1.02 to -1.16 g/MWd, compared to a typical LWR actinide generation rate of 0.303 g/MWd. However, when using the same parameters, the sodium-cooled case went subcritical after 0.2 to 0.8 effective full power years, and the lead-bismuth cooled case ranged from 1.5 to 4.5 effective full power years. (author)

  18. Performance Comparison of Metallic, Actinide Burning Fuel in Lead-Bismuth and Sodium Cooled Fast Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, Kevan Dean; Herring, James Stephen; Mac Donald, Philip Elsworth

    2001-04-01

    Various methods have been proposed to “incinerate” or “transmutate” the current inventory of trans-uranic waste (TRU) that exits in spent light-water-reactor (LWR) fuel, and weapons plutonium. These methods include both critical (e.g., fast reactors) and non-critical (e.g., accelerator transmutation) systems. The work discussed here is part of a larger effort at the Idaho National Engineering and Environmental Laboratory (INEEL) and at the Massachusetts Institute of Technology (MIT) to investigate the suitability of lead and lead-alloy cooled fast reactors for producing low-cost electricity as well as for actinide burning. The neutronics of non-fertile fuel loaded with 20 or 30-wt% light water reactor (LWR) plutonium plus minor actinides for use in a lead-bismuth cooled fast reactor are discussed in this paper, with an emphasis on the fuel cycle life and isotopic content. Calculations show that the average actinide burn rate is similar for both the sodium and lead-bismuth cooled cases ranging from -1.02 to -1.16 g/MWd, compared to a typical LWR actinide generation rate of 0.303 g/MWd. However, when using the same parameters, the sodium-cooled case went subcritical after 0.2 to 0.8 effective full power years, and the lead-bismuth cooled case ranged from 1.5 to 4.5 effective full power years.

  19. A calculation for radial expectation values of helium like actinide ions (Z=89-93)

    Science.gov (United States)

    Ürer, G.; Arslan, M.; Balkaya, E.; Keçeli, A.

    2016-03-01

    Radial expectation values, , for helium like actinides (ZAc=89, ZTh=90, ZPa=91, ZU=92, and ZNp=93) are reported using the Multiconfiguration Hartree-Fock (MCHF) within the framework Breit-Pauli corrections. Atomic data as energy levels, wavelengths, weighted oscillator strengths, and transition probabilities for allowed and forbidden transitions need these calculations. The obtained results are compared available works.

  20. Build-up and decay of fuel actinides in the fuel cycle of nuclear reactors

    International Nuclear Information System (INIS)

    For boiling water reactors, pressurized light-water reactors, pressure-tube-type heavy water reactors, high-temperature gas-cooled reactors, and sodium-cooled fast breeder reactors, uranium fueled and mixed-oxide fueled, each of 1000 MWe, the following have been studied: (1) quantities of plutonium and other fuel actinides built up in the reactor, (2) cooling behaviors of activities of plutonium and other fuel actinides in the spent fuels, and (3) activities of plutonium and other fuel actinides in the high-level reprocessing wastes as a function of storage time. The neutron cross section and decay data of respective actinide nuclides are presented, with their evaluations. For effective utilization of the uranium resources and easy reprocessing and high-level waste management, a thermal reactor must be fueled with uranium; the plutonium produced in a thermal reactor should be used in a fast reactor; and the plutonium produced in the blanket of a fast reactor is more appropriate for a fast reactor than that from a thermal reactor. (auth.)

  1. Intercomparison of derived integral data from evaluated data libraries of the actinides

    International Nuclear Information System (INIS)

    Resonance integrals and fission spectrum averaged cross-sections are calculated for the actinides from all recent major evaluated libraries. Whenever possible the results are compared against measurements. It is found that the experimental data are scarce and that there exist considerable differences between experimentally measured data and those derived from the evaluated libraries. (author). 93 refs and tabs

  2. Present status of research activities on transmutation of actinides in Japan

    International Nuclear Information System (INIS)

    In Japan, the idea to make use of transmutation for the final disposal method of HLW was first examined by Ichimiya, Amano, Hamada et al., when the Japan Atomic Industry forum had organized a study committee for HLW treatment in 1973. This article has the scope to outline the present research activities on transmutation of actinides in Japan

  3. New limit of $^{244}$Pu on Earth points to rarity of actinide nucleosynthesis

    CERN Document Server

    Wallner, A; Feige, J; Feldstein, C; Knie, K; Korschinek, G; Kutschera, W; Ofan, A; Paul, M; Quinto, F; Rugel, G; Steier, P

    2015-01-01

    Half of the heavy elements including all actinides are produced in r-process nucleosynthesis whose sites and history still remain a mystery. If continuously produced, the Interstellar Medium (ISM) is expected to build up a quasi-steady state of abundances of short-lived nuclides (with half-lives <100My), including actinides produced in r-process nucleosynthesis. Their existence in today's ISM would serve as a radioactive clock and would establish that their production was recent. In particular $^{244}$Pu, a radioactive actinide nuclide (81 My half-life), can place strong constraints on recent r-process frequency and production yield. Here we report on the detection of live interstellar $^{244}$Pu, archived in Earth's deep-sea floor during the last 25 My, at abundances lower by about two orders of magnitude than expected from continuous production in the Galaxy. This large discrepancy may signal a rarity of actinide r-process nucleosynthesis sites, compatible with neutron-star mergers or with a small subset...

  4. Comparison of experimental and theoretical binding and transition energies in the actinide region. [Review

    Energy Technology Data Exchange (ETDEWEB)

    Krause, M.O.; Nestor, C.W. Jr.

    1977-01-01

    The status of experimental and theoretical binding and transition energy determinations is reviewed extending the comparison between experiment and theory to encompass representative series of data for all actinides. This comprehensive comparison reveals areas where improvements may be indicated, showing whether theoretical treatments including all known contributions to the lowest order would be adequate in all instances. 45 references. (JFP)

  5. Possibility of fusion power reactor to transmute minor actinides of spent nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Serikov, A. E-mail: serikov@nfi.kiae.ru; Shatalov, G.; Sheludjakov, S.; Shpansky, Yu.; Vasiliev, N

    2002-12-01

    A possibility to use fusion power reactor (FPR) is considered for burning long-life elements of spent nuclear fuel in parallel with energy production. In this study a principal design of FPR blanket was examined for transmutation of long-life minor actinides (Np, Am, Cm). A production of minor actinide isotopes is equal to 20-30 kg/1 GW{sub (e)} year for now operating fission reactors, and their amounts will rise with the expected growth of fission reactor power. These isotopes have long-life time and can be dangerous in big amounts in future. Plutonium isotopes are not included in an assumption that they will be used in fission reactors. The major goals of the study were to determine FPR blanket composition corresponding to fast transmutation rate of actinides and tritium self-supply simultaneously. Tritium breeding ratio (TBR) was obtained at level 1.11 for water cooling and reached up 1.56 in variant with helium-cooled assemblies with Np nitride. It was concluded that rows with actinides from processed waste fuel should be arranged near the plasma first wall. Advantages of helium above water cooling are observed in the twice-increased loading of waste fissionable materials and essential increase of achievable TBR. Burnout of Np, Am, Cm would remain at a level {approx}40-50% after 4 full power years.

  6. Method of loading organic materials with group III plus lanthanide and actinide elements

    Energy Technology Data Exchange (ETDEWEB)

    Bell, Zane W. (Oak Ridge, TN); Huei-Ho, Chuen (Oak Ridge, TN); Brown, Gilbert M. (Knoxville, TN); Hurlbut, Charles (Sweetwater, TX)

    2003-04-08

    Disclosed is a composition of matter comprising a tributyl phosphate complex of a group 3, lanthanide, actinide, or group 13 salt in an organic carrier and a method of making the complex. These materials are suitable for use in solid or liquid organic scintillators, as in x-ray absorption standards, x-ray fluorescence standards, and neutron detector calibration standards.

  7. 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

  8. 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

  9. X-ray study of chemical bonding in actinides(IV) and lanthanides(III) hexa-cyanoferrates

    International Nuclear Information System (INIS)

    Bimetallic cyanide molecular solids derived from Prussian blue are well known to foster long-range magnetic ordering and show an intense inter-valence charge transfer band resulting from an exchange interaction through the cyanide-bridge. For those reasons the ferrocyanide and ferricyanide building blocks have been chosen to study electronic delocalization and covalent character in actinide bonding using an experimental and theoretical approach based on X-ray absorption spectroscopy. In 2001, the actinide (IV) and early lanthanides (III) hexacyanoferrate have been found by powder X-ray diffraction to be isostructural (hexagonal, P63/m group). Here, extended X-ray Absorption Fine Structure (EXAFS) at the iron K-edge and actinide L3-edge have been undertaken to probe the local environment of both actinides and iron cations. In an effort to describe the cyano bridge, a double edge fitting procedure including both iron and actinide edges and based on multiple scattering approach has been developed. We have also investigated the electronic properties of these molecular solids. Low energy electronic transitions have been used iron L2,3 edge, nitrogen and carbon K-edge and also actinides N4,5 edge to directly probe the valence molecular orbitals of the complex. Using a phenomenological approach, a clear distinctive behaviour between actinides and lanthanides has been shown. Then a theoretical approach using quantum chemistry calculation has shown more specifically the effect of covalency in the actinide-ferrocyanide bond. More specifically, π interactions were underlined by both theoretical and experimental methods. Finally, in agreement with the ionic character of the lanthanide bonding no inter-valence charge transfer has been observed in the corresponding optical spectra of these compounds. On the contrary, optical spectra for actinides adducts (except for thorium) show an intense inter-valence charge transfer band like in the transition metal cases which is

  10. Uptake of natural and anthropogenic actinides in vegetable crops grown on a contaminated lake bed

    International Nuclear Information System (INIS)

    Activity concentrations and plant/soil concentration ratios (CRs) of 239,240Pu, 241Am, 244Cm, 232Th, and 238U were determined for three vegetable crops grown on an exposed, contaminated lake bed of a former reactor cooling reservoir in South Carolina, USA. The crops included greens and tubers of turnips (Brassica rapa var. white-globe), bush beans (Phaseolus vulgaris), and husks and kernels of sweet corn (Zea mays var. silver queen). Although all plots were fertilized, some received K2SO4, while others received no K2SO4. The K2SO4 fertilizer treatment generally lowered activity concentrations for 241Am, 244Cm, 232Th and 238U, but differences were statistically significant for 241Am and 244Cm only. Highly significant differences occurred in activity concentrations among actinides and among crops. In general, turnip greens exhibited the highest uptake for each of the actinides measured, while corn kernels had the least. For turnip greens, geometric mean CRs ranged from 2.3×10-3 for 239,240Pu to 5.3×10-2 for 241Am (no K2SO4 fertilizer). For corn kernels, geometric mean CRs ranged from 2.1×10-5 for 239,240Pu and 232Th to 1.5×10-3 for 244Cm (no K fertilizer). In general, CRs across all crops for the actinides were in the order: 244Cm>241Am>238U>232Th >239,240Pu. Lifetime health risks from consuming crops contaminated with anthropogenic actinides were similar to the risks from naturally occurring actinides in the same crops (total ∼2×10-6); however, these risks were only ∼0.3% of the risk from consuming the same crops contaminated with 137Cs. (author)

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

    International Nuclear Information System (INIS)

    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 HNO3. 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/H2O 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)

  12. The role of actinide burning and the Integral Fast Reactor in the future of nuclear power

    Energy Technology Data Exchange (ETDEWEB)

    Hollaway, W.R.; Lidsky, L.M.; Miller, M.M.

    1990-12-01

    A preliminary assessment is made of the potential role of actinide burning and the Integral Fast Reactor (IFR) in the future of nuclear power. The development of a usable actinide burning strategy could be an important factor in the acceptance and implementation of a next generation of nuclear power. First, the need for nuclear generating capacity is established through the analysis of energy and electricity demand forecasting models which cover the spectrum of bias from anti-nuclear to pro-nuclear. The analyses take into account the issues of global warming and the potential for technological advances in energy efficiency. We conclude, as do many others, that there will almost certainly be a need for substantial nuclear power capacity in the 2000--2030 time frame. We point out also that any reprocessing scheme will open up proliferation-related questions which can only be assessed in very specific contexts. The focus of this report is on the fuel cycle impacts of actinide burning. Scenarios are developed for the deployment of future nuclear generating capacity which exploit the advantages of actinide partitioning and actinide burning. Three alternative reactor designs are utilized in these future scenarios: The Light Water Reactor (LWR); the Modular Gas-Cooled Reactor (MGR); and the Integral Fast Reactor (FR). Each of these alternative reactor designs is described in some detail, with specific emphasis on their spent fuel streams and the back-end of the nuclear fuel cycle. Four separation and partitioning processes are utilized in building the future nuclear power scenarios: Thermal reactor spent fuel preprocessing to reduce the ceramic oxide spent fuel to metallic form, the conventional PUREX process, the TRUEX process, and pyrometallurgical reprocessing.

  13. ENHANCED CHEMICAL CLEANING OF SRS WASTE TANKS TO IMPROVE ACTINIDE SOLUBILITY

    Energy Technology Data Exchange (ETDEWEB)

    Rudisill, T.; Thompson, M.

    2011-09-20

    Processes for the removal of residual sludge from SRS waste tanks have historically used solutions containing up to 0.9 M oxalic acid to dissolve the remaining material following sludge removal. The selection of this process was based on a comparison of a number of studies performed to evaluate the dissolution of residual sludge. In contrast, the dissolution of the actinide mass, which represents a very small fraction of the waste, has not been extensively studied. The Pu, Np, and Am in the sludge is reported to be present as hydrated and crystalline oxides. To identify aqueous solutions which have the potential to increase the solubility of the actinides, the alkaline and mildly acidic test solutions shown below were selected as candidates for use in a series of solubility experiments. The efficiency of the solutions in solubilizing the actinides was evaluated using a simulated sludge prepared by neutralizing a HNO{sub 3} solution containing Pu, Np, and Am. The hydroxide concentration was adjusted to a 1.2 M excess and the solids were allowed to age for several weeks prior to starting the experiments. The sludge was washed with 0.01 M NaOH to prepare the solids for use. Following the addition of an equal portion of the solids to each test solution, the concentrations of Pu, Np, and Am were measured as a function of time over a 792 h (33 day) period to provide a direct comparison of the efficiency of each solution in solubilizing the actinide elements. Although the composition of the sludge was limited to the hydrated actinide oxides (and did not contain other components of demonstrated importance), the results of the study provides guidance for the selection of solutions which should be evaluated in subsequent tests with a more realistic surrogate sludge and actual tank waste.

  14. 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.)

  15. Experimental Findings On Minor Actinide And Lanthanide Separations Using Ion Exchange

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, D. T.; Shehee, T. C.; Clearfield, A.

    2013-09-17

    This project seeks to determine if inorganic or hybrid inorganic ion-exchange materials can be exploited to provide effective americium and curium separations. Specifically, we seek to understand the fundamental structural and chemical factors responsible for the selectivity of the tested ion-exchange materials for actinide and lanthanide ions. During FY13, experimental work focused in the following areas: (1) investigating methods to oxidize americium in dilute nitric acid with subsequent ion-exchange performance measurements of ion exchangers with the oxidized americium and (2) synthesis, characterization and testing of ion-exchange materials. Ion-exchange materials tested included alkali titanates, alkali titanosilicates, carbon nanotubes and group(IV) metal phosphonates. Americium oxidation testing sought to determine the influence that other redox active components may have on the oxidation of Am(III). Experimental findings indicated that Pu(IV) is oxidized to Pu(VI) by peroxydisulfate, but there are no indications that the presence of plutonium affects the rate or extent of americium oxidation at the concentrations of peroxydisulfate being used. Tests also explored the influence of nitrite on the oxidation of Am(III). Given the formation of Am(V) and Am(VI) in the presence of nitrite, it appears that nitrite is not a strong deterrent to the oxidation of Am(III), but may be limiting Am(VI) by quickly reducing Am(VI) to Am(V). Interestingly, additional absorbance peaks were observed in the UV-Vis spectra at 524 and 544 nm in both nitric acid and perchloric acid solutions when the peroxydisulfate was added as a solution. These peaks have not been previously observed and do not correspond to the expected peak locations for oxidized americium in solution. Additional studies are in progress to identify these unknown peaks. Three titanosilicate ion exchangers were synthesized using a microwave-accelerated reaction system (MARS) and determined to have high affinities

  16. 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

  17. Critical analysis of the data on complexation of lanthanides and actinides by natural organic matter: particular case of humic substances

    International Nuclear Information System (INIS)

    This document proposes a critical analysis of the models that describe the actinides and lanthanides complexation by natural organic matter in general and by humic substances in particular. In order to better delimit the particular properties of these substances the most influent physical and chemical properties on complexation are recalled as a preamble. Models as well as data that has been used are reviewed, compiled, and eventually compared to independent data in order to identify (i) their application domain, (ii) the possible simplifications which permit to obtain operational models, (iii) the conditions in which simplifications cannot be ascertained yet, and (iv) the data or fields of knowledge which are still too uncertain. A comparison between the different models is proposed in order to adapt parameters from one model to another minimising the experimental acquisitions, or at least to focus on missing data. Usually, data on the complexation of free ions Mz+ are reliable; as soon as hydrolysis, or competition with another ligand in general, in at stake data are much less reliable. Predictions from models are much more uncertain: formation of mixed complexes with hydroxide or carbonate anions is not univocal whatever the modelling strategy. Hints for transfer functions between models which are believed to be incompatible could be explored in order to justify necessary simplifications for using operational modelling. Influence on the solubility of oxides could be quantified, but it is difficult to clearly separate it from colloidal particles stabilisation. The account of the competition between cations by the models has also been tested. In view of the small number of available experimental data there still lie some uncertainties especially for the media that are close to neutrality and in the case of competition with magnesium, but overall in the case of the competition with aluminium and iron. The influence of redox activity of humic substances is also

  18. Radiolysis of actinides and technetium in alkaline media

    Energy Technology Data Exchange (ETDEWEB)

    Delegard, C.H., Westinghouse Hanford

    1996-07-10

    The {gamma}-radiolysis of aerated alkaline aqueous solutions of Np(V), Np(VI), Pu(VI), Tc(IV), Tc(V), and TC(VII) was studied in the absence of additives and in the presence of CO{sub 3}{sup 2-}, NO{sub 3}{sup -}, NO{sub 2}{sup -}, EDTA, formate, and other organic compounds. The radiolytic reduction of Np(V), Np(VI), Pu(VI), and TC(VII) under different experimental conditions was examined in detail. The addition of EDTA, formate, and alcohols was found to considerably increase the radiation-chemical reduction yields. The formation of the Np(V) peroxo complex was observed in the {gamma}-radiolysis of alkaline aqueous solutions of Np (VI) in the presence of nitrate.

  19. Potentiometric Sensor for Real-Time Remote Surveillance of Actinides in Molten Salts

    Energy Technology Data Exchange (ETDEWEB)

    Natalie J. Gese; Jan-Fong Jue; Brenda E. Serrano; Guy L. Fredrickson

    2012-07-01

    A potentiometric sensor is being developed at the Idaho National Laboratory for real-time remote surveillance of actinides during electrorefining of spent nuclear fuel. During electrorefining, fuel in metallic form is oxidized at the anode while refined uranium metal is reduced at the cathode in a high temperature electrochemical cell containing LiCl-KCl-UCl3 electrolyte. Actinides present in the fuel chemically react with UCl3 and form stable metal chlorides that accumulate in the electrolyte. This sensor will be used for process control and safeguarding of activities in the electrorefiner by monitoring the concentrations of actinides in the electrolyte. The work presented focuses on developing a solid-state cation conducting ceramic sensor for detecting varying concentrations of trivalent actinide metal cations in eutectic LiCl-KCl molten salt. To understand the basic mechanisms for actinide sensor applications in molten salts, gadolinium was used as a surrogate for actinides. The ß?-Al2O3 was selected as the solid-state electrolyte for sensor fabrication based on cationic conductivity and other factors. In the present work Gd3+-ß?-Al2O3 was prepared by ion exchange reactions between trivalent Gd3+ from GdCl3 and K+-, Na+-, and Sr2+-ß?-Al2O3 precursors. Scanning electron microscopy (SEM) was used for characterization of Gd3+-ß?-Al2O3 samples. Microfocus X-ray Diffraction (µ-XRD) was used in conjunction with SEM energy dispersive X-ray spectroscopy (EDS) to identify phase content and elemental composition. The Gd3+-ß?-Al2O3 materials were tested for mechanical and chemical stability by exposing them to molten LiCl-KCl based salts. The effect of annealing on the exchanged material was studied to determine improvements in material integrity post ion exchange. The stability of the ß?-Al2O3 phase after annealing was verified by µ-XRD. Preliminary sensor tests with different assembly designs will also be presented.

  20. A contribution to the study of the extraction of mineral acids and of actinide (IV) and (VI) cations by N,N-dialkylamides; Contribution a l'etude de l'extraction d'acides mineraux et de cations actinides aux degres d'oxydation (IV) et (VI) par des N,N-dialkylamides

    Energy Technology Data Exchange (ETDEWEB)

    Condamines, N.

    1990-03-15

    N,N-dialkylamides are alternate extractants to tributylphosphate, TBP, for the actinides separation in nuclear fuel reprocessing. N,N-di (2-ethyl hexyl) butyramide and N,N-di (2 ethyl hexyl) isobutyramide are selected for their sufficient extraction and partition ability towards actinides (IV) and (VI) without coextracting fission products. Mechanisms of HNO{sub 3}, UO{sub 2}{sup 2+}, Pu{sup 4+}, Th{sup 4+} are investigated. Nitric acid extraction is due to the competitive formation of the species (HNO{sub 3})L{sub 2}, (HNO{sub 3})L, (HNO{sub 3}){sub 2}L (L: DOBA or DOiBA). An hydrogen bond is the driving force of the transfer. For low acidity media, amides are neutral extractants. Physical interactions, between free ligand and metallic complex, arise for high amide concentrations. Taking into account the non-ideality of the organic medium by a hard spheres mixture model, we estimate that such interactions are far from negligible and very specific to the amide group. Unlike TBP, when increasing acidity, amides behave as anionic extractants. DOBA and DOiBA appear to be satisfactory extractants for fuel reprocessing.

  1. Neutron capture measuremetns on minor actinides at the n_TOF facility at CERN: past, present and future

    OpenAIRE

    Cano Ott, Daniel; Colonna, Nicola; Tagliente, G; Belloni, Fabio; Calviño Tavares, Francisco; Cortés Rossell, Guillem Pere; Poch Parés, Agustí; Pretel Sánchez, Carme

    2011-01-01

    The successful development of advanced nuclear systems for sustainable energy production and nuclear waste management depends on high quality nuclear data libraries. Recent sensitivity stud- ies and reports [1-3] have identi ed the need for substantially improving the accuracy of neutron cross-section data for minor actinides. The n TOF collaboration has initiated an ambitious exper- imental program for the measurement of neutron capture cross sections of minor actinides. Two e...

  2. Pyrochlore based glass-ceramics for the immobilization of actinide-rich nuclear wastes: From concept to reality

    Science.gov (United States)

    Zhang, Y.; Zhang, Z.; Thorogood, G.; Vance, E. R.

    2013-01-01

    Pyrochlore based glass-ceramics have been developed, from concept to reality, for the immobilization of actinide-rich nuclear wastes. Compared with zirconolite based glass-ceramics, they are less sensitive to the processing redox conditions and can double actinide waste loadings thus decreasing volumes of the consolidated waste forms, and subsequently reducing the interim storage and disposal costs. More importantly, they provide an alternative flexible system to tackle radioactive wastes arising from the advanced nuclear reactors.

  3. Computational Study of Covalency and Complexation in Actinides using Static and Dynamic Simulation and Topological Density Analysis

    OpenAIRE

    Kirker, I. D. J.

    2013-01-01

    The separation of minor actinides such as americium and curium from other actinide and lanthanide-bearing components of used nuclear fuel is a necessary part of post-processing and recycling this fuel into storable components and new fuel material. Separation ratios can be optimised using a comprehensive understanding of the differences between these elements and their aqueous chemistry. This work uses computational simulation to investigate bonding behaviour and covalency differences between...

  4. Comparison of actinides and fission products recycling scheme with the normal plutonium recycling scheme in fast reactors

    OpenAIRE

    Salahuddin Asif; Iqbal Masood

    2013-01-01

    Multiple recycling of actinides and non-volatile fission products in fast reactors through the dry re-fabrication/reprocessing atomics international reduction oxidation process has been studied as a possible way to reduce the long-term potential hazard of nuclear waste compared to that resulting from reprocessing in a wet PUREX process. Calculations have been made to compare the actinides and fission products recycling scheme with the normal plutonium recycling scheme in a fast reactor....

  5. Lanthanides and actinides extraction by calixarenes containing CMPO groups; Extraction des lanthanides et des actinides au moyen de calixarenes portant des groupements CMPO

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Carrera, A

    2001-07-01

    In the framework of the French program SPIN concerning the radioactive waste management, researches are performed to develop processes allowing the separation of long-lived radioisotopes in order to their transmutation or their specific conditioning. These studies deal with the extraction and the separation of trivalent lanthanides and actinides in acid solution. Many systems ''calixarene-diluent-aqueous phase'' are examined by extraction liquid-liquid and membrane transport. The extraction efficiency and the selectivity of the synthesized calixarene-CMPO and of the CMPO are compared with these cations, as the nitric acid extraction by these molecules. (A.L.B.)

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

    International Nuclear Information System (INIS)

    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 241Am and 244Cm in the form of Am2O3, Cm2O3, and Am6Cm(RE)7O21, where (RE) represents a mixture of lanthanides. For the cross-section determinations, the samples are milligram quantities of actinide oxides of 248Cm, 246Cm, 244Cm, 243Cm, 243Am, 241Am, 244Pu, 242Pu, 241Pu, 240Pu, 239Pu, 238Pu, 237Np, 238U, 236U, 235U, 234U, 233U, 232Th, 230Th, and 231Pa 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

  7. Dounreay PFR irradiation history for the joint US/UK actinide sample exposures

    International Nuclear Information System (INIS)

    The operating history of the Dounreay Prototype Fast Reactor is presented to the extent that it is relevant to the irradiation of actinide specimens that were subsequently analyzed at Oak Ridge National Laboratory (ORNL). Three fuel pins with actinide samples were irradiated from July 1982 to July 1988 and returned to ORNL for analysis. They contained isotopes of elements from thorium to curium. The times when each of these fuel pins were in the reactor core are described as are the operating power levels and neutron spectra. The appendices give daily power levels of the reactor as well as six-group neutron energy spectra for various times and axial positions in the core

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-07-01

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  11. Recovery of actinides from actinide–aluminium alloys by chlorination: Part II

    Energy Technology Data Exchange (ETDEWEB)

    Souček, P., E-mail: pavel.soucek@ec.europa.eu [European Commission, JRC, Institute for Transuranium Elements, Postfach 2340, 76125 Karlsruhe (Germany); Cassayre, L. [Laboratoire de Génie Chimique (LGC), Département Procédés Electrochimiques, CNRS-UMR 5503, Université de Toulouse III – Paul Sabatier, 31062 Toulouse Cedex 9 (France); Eloirdi, R.; Malmbeck, R.; Meier, R.; Nourry, C.; Claux, B.; Glatz, J.-P. [European Commission, JRC, Institute for Transuranium Elements, Postfach 2340, 76125 Karlsruhe (Germany)

    2014-04-01

    A chlorination route is being investigated for recovery of actinides from actinide–aluminium alloys, which originate from pyrochemical recovery of actinides from spent metallic nuclear fuel by electrochemical methods in molten LiCl–KCl. In the present work, the most important steps of this route were experimentally tested using U–Pu–Al alloy prepared by electrodeposition of U and Pu on solid aluminium plate electrodes. The investigated processes were vacuum distillation for removal of the salt adhered on the electrode, chlorination of the alloy by chlorine gas and sublimation of the AlCl{sub 3} formed. The processes parameters were set on the base of a previous thermochemical study and an experimental work using pure UAl{sub 3} alloy. The present experimental results indicated high efficiency of salt distillation and chlorination steps, while the sublimation step should be further optimised.

  12. Method of processing waste water containing actinide element by fixed tannin

    International Nuclear Information System (INIS)

    Since the waste water from a nuclear power plant is generally in an alkaline range above pH 8, in the case of processing waste water by using fixed tannin, fixed tannin is partially leached to unstable, and the adsorbing elimination rate of actinide elements contained in waste water is decreased. Accordingly, the fixed tannin is immersed and brought into contact with an aqueous solution of ammonia for pre-treatment. it is necessary that the pH value of the aqueous solution of ammonia used is higher than that of the waste water containing the actinide elements, and preferably, within a range of 10 to 12. The time of contact for ensuring the effect of the pre-treatment is at least 30 minutes for the lower limit and 60 minutes for the upper limit. In this way, the adsorbing performance itself can be improved and the processing performance for radioactive waste water can be improved. (T.M.)

  13. Formal oxidation potentials of actinide couples in K10P2W17O61 solutions

    International Nuclear Information System (INIS)

    The formal oxidation potentials of the M(VI)/M(V), M(V)/M(IV), and M(IV)/M(III) couples for actinides from U to No and of the M(IV)/M(III) couples for some actinides in 1 M H+ or 1 M Na+ (pH ∼5-5.5) solutions containing K10P2W17O61 were calculated from the data on stability of complexes of f element ions with the unsaturated heteropolytungstate anion P2W17O 6110-. In some cases, the previously accepted values were subjected to major revision, especially the potentials of the An(V)/An(IV) couples. Problems arising in measuring the potentials of the couples involving Np(III) and Pu(III) which react with the heteropolyanion to form a heteropoly blue are discussed. The potentials of some M(III)/M(II) couples are estimated

  14. Behavior of actinide containing glasses during gamma irradiation in a saturated tuff environment

    International Nuclear Information System (INIS)

    The influence of gamma irradiation of the reaction of actinide doped SRL 165 and PNL 76-68 glasses in a saturated tuff environment has been studied in a series of tests lasting up to 56 days. The reaction, and subsequent actinide release, of both glasses depends on the dynamic interaction between radiolysis effects which cause the solution pH to become more acidic and glass reaction which drives the pH more basic. The use of large gamma irradiation dose rates to accelerate reactions that would occur in an actual repository radiation field may affect this dynamic balance by unduly influencing the mechanism of the glass-water reaction. Comparisons are made between the present results and data obtained by reacting the same or similar glasses using MCC-1 and NNWSI rock cup procedures. 11 references, 3 figures

  15. Behavior of actinide containing glassed during gamma irradiation in a saturated tuff environment

    International Nuclear Information System (INIS)

    The influence of gamma irradiation on the reaction of actinide doped SRL 165 and PNL 76-68 glasses in a saturated tuff environment has been studied in a series of tests lasting up to 56 days. The reaction, and subsequent actinide release, of both glasses depend on the dynamic interaction between radiolysis effects which cause the solution pH to become more acidic and glass reaction which drives the pH more basic. The use of large gamma irradiation dose rates to accelerate reactions that would occur in an actual repository radiation field may affect this dynamic balance by unduly influencing the mechanism of the glass-water reaction. Comparisons are made between the present results and data obtained by reacting the same or similar glasses using MCC-1 and NNWSI rock cup procedures. 11 refs., 3 figs

  16. A Lane consistent optical model potential for nucleon scattering on actinide nuclei with extended coupling

    Directory of Open Access Journals (Sweden)

    Quesada José Manuel

    2016-01-01

    Full Text Available An extension for odd-A actinides of a previously derived dispersive coupledchannel optical model potential (OMP for 238U and 232Th nuclei is presented. It is used to fit simultaneously all the available experimental databases including neutron strength functions for nucleon scattering on 232Th, 233,235,238U and 239Pu nuclei. Quasi-elastic (p,n scattering data on 232Th and 238U to the isobaric analogue states of the target nucleus are also used to constrain the isovector part of the optical potential. For even-even (odd actinides almost all low-lying collective levels below 1 MeV (0.5 MeV of excitation energy are coupled. OMP parameters show a smooth energy dependence and energy independent geometry.

  17. Speciation, Mobility and Fate of Actinides in the Groundwater at the Hanford Site

    International Nuclear Information System (INIS)

    Plutonium and other actinides represent important contaminants in the groundwater and vadose zone at Hanford and other DOE sites. The distribution and migration of these actinides in groundwater must be understood so that these sites can be carefully monitored and effectively cleaned up, thereby minimizing risks to the public. The objective of this project was to obtain field data on the chemical and physical forms of plutonium in groundwater at the Hanford site. We focused on the 100-k and 100-n areas near the Columbia River, where prior reactor operations and waste storage was in close proximity to the river. In particular, a unique set of technical approaches were combined to look at the details of Pu speciation in groundwater, as thus its chemical affinity for soil surfaces and solubility in groundwater, as these impact directly the migration rates off site and possible mitigation possibilities one might undertake to control, or at least better monitor these releases

  18. Prospects of subcritical molten salt reactor for minor actinides incineration in closed fuel cycle

    Energy Technology Data Exchange (ETDEWEB)

    Alekseev, Pavel N.; Balanin, Andrey L.; Dudnikov, Anatoly A.; Fomichenko, Petr A.; Nevinitsa, Vladimir A.; Frolov, Aleksey A.; Lubina, Anna S.; Sedov, Aleksey A.; Subbotin, Aleksey S.; Blandinsky, Viktor Yu. [Nuclear Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation)

    2015-09-15

    A subcritical molten salt reactor is proposed for minor actinides (separated from spent fuel VVER-1000 light water reactor) incineration and for {sup 233}U conversion from {sup 232}Th. Here the subcritical molten salt reactor with fuel composition of heavy nuclide fluorides in molten LiF - NaF - KF salt and with external neutron source, based on 1 GeV proton accelerator and molten salt cooled tungsten target is considered. The paper presents the results of parametrical analysis of equilibrium nuclide composition of molten salt reactor with minor actinides feed in dependence of core dimensions, average neutron flux and external neutron source intensity. Reactor design is defined; requirements to external neutron source are posed; heavy nuclides equilibrium and fuel cycle main parameters are calculated.

  19. Design of an Actinide Burning, Lead-Bismuth Cooled Reactor That Produces Low Cost Electricity

    Energy Technology Data Exchange (ETDEWEB)

    C. Davis; S. Herring; P. MacDonald; K. McCarthy; V. Shah; K. Weaver (INEEL); J. Buongiorno; R. Ballinger; K. Doyoung; M. Driscoll; P. Hejzler; M. Kazimi; N. Todreas (MIT)

    1999-07-01

    The purpose of this project is to investigate the suitability of lead-bismuth cooled fast reactors for producing low-cost electricity as well as for actinide burning. The goal is to identify and analyze the key technical issues in core neutronics, materials, thermal-hydraulics, fuels, and economics associated with the development of this reactor concept. The choice of lead-bismuth for the reactor coolant is an actinide burning fast reactor offers enhanced safety and reliability. The advantages of lead-bismuth over sodium as a coolant are related to the following material characteristics: chemical inertness with air and water; higher atomic number; lower vapor pressure at operating temperatures; and higher boiling temperature. Given the status of the field, it was agreed that the focus of this investigation in the first two years will be on the assessment of approaches to optimize core and plant arrangements in order to provide maximum safety and economic potential in this type of reactor.

  20. RELATIVISTIC EFFECTS ON THE EQUATION OF STATE OF THE LIGHT ACTINIDES

    Energy Technology Data Exchange (ETDEWEB)

    Landa, A; Soderlind, P

    2005-11-04

    The effect of the relativistic spin-orbit (SO) interaction on the bonding in the early actinides has been investigated by means of electronic-structure calculations. Specifically, the equation of state (EOS) for the face-centered cubic (fcc) model systems of these metals have been calculated from the first-principles density-functional theory (DFT). Traditionally, the SO interaction in electronic-structure methods is implemented as a perturbation to the Hamiltonian that is solved for basis functions that explicitly do not depend on SO coupling. Here this approximation is shown to compare well with the fully relativistic Dirac treatment. It is further shown that SO coupling has a gradually increasing effect on the EOS as one proceeds through the actinides and the effect is diminished as density increases.