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Sample records for du thorium irradie

  1. PROCESS FOR CONTINUOUSLY SEPARATING IRRADIATION PRODUCTS OF THORIUM

    DOEpatents

    Hatch, L.P.; Miles, F.T.; Sheehan, T.V.; Wiswall, R.H.; Heus, R.J.

    1959-07-01

    A method is presented for separating uranium-233 and protactinium from thorium-232 containing compositions which comprises irradiating finely divided particles of said thorium with a neutron flux to form uranium-233 and protactinium, heating the neutron-irradiated composition in a fluorine and hydrogen atmosphere to form volatile fluorides of uranium and protactinium and thereafter separating said volatile fluorides from the thorium.

  2. Inhalation radiotoxicity of irradiated thorium as a heavy water reactor fuel

    SciTech Connect

    Edwards, G.W.R.; Priest, N.D.; Richardson, R.B.

    2013-07-01

    The online refueling capability of Heavy Water Reactors (HWRs), and their good neutron economy, allows a relatively high amount of neutron absorption in breeding materials to occur during normal fuel irradiation. This characteristic makes HWRs uniquely suited to the extraction of energy from thorium. In Canada, the toxicity and radiological protection methods dealing with personnel exposure to natural uranium (NU) spent fuel (SF) are well-established, but the corresponding methods for irradiated thorium fuel are not well known. This study uses software to compare the activity and toxicity of irradiated thorium fuel ('thorium SF') against those of NU. Thorium elements, contained in the inner eight elements of a heterogeneous high-burnup bundle having LEU (Low-enriched uranium) in the outer 35 elements, achieve a similar burnup to NU SF during its residence in a reactor, and the radiotoxicity due to fission products was found to be similar. However, due to the creation of such inhalation hazards as U-232 and Th-228, the radiotoxicity of thorium SF was almost double that of NU SF after sufficient time has passed for the decay of shorter-lived fission products. Current radio-protection methods for NU SF exposure are likely inadequate to estimate the internal dose to personnel to thorium SF, and an analysis of thorium in fecal samples is recommended to assess the internal dose from exposure to this fuel. (authors)

  3. Thorium silicate compound as a solid-state target for production of isomeric thorium-229 nuclei by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Borisyuk, P. V.; Vasilyev, O. S.; Lebedinskii, Y. Y.; Krasavin, A. V.; Tkalya, E. V.; Troyan, V. I.; Habibulina, R. F.; Chubunova, E. V.; Yakovlev, V. P.

    2016-09-01

    In this paper, we discuss an idea of the experiment for excitation of the isomeric transition in thorium-229 nuclei by irradiating with electron beam targets with necessary physical characteristics. The chemical composition and bandgap of ThSi10O22 were determined by X-ray photoelectron spectroscopy and reflection electron energy loss spectroscopy. It was found that the energy gap is equal to 7.7 eV and does not change when the target is exposed to a medium energy electron beam for a long time. This indicates that the compound possesses high electron-beam resistance. A quantitative estimation of the output function of isomeric thorium-229 nuclei generated by interaction of nuclei with the secondary electron flow formed by irradiating the solid-state ThSi10O22-based target is given. The estimation shows that ThSi10O22 is a promising thorium-containing target for investigating excitation of the nuclear low-lying isomeric transition in the thorium-229 isotope using medium-energy electrons.

  4. Status of the Norwegian thorium light water reactor (LWR) fuel development and irradiation test program

    SciTech Connect

    Drera, S.S.; Bjork, K.I.; Kelly, J.F.; Asphjell, O.

    2013-07-01

    Thorium based fuels offer several benefits compared to uranium based fuels and should thus be an attractive alternative to conventional fuel types. In order for thorium based fuel to be licensed for use in current LWRs, material properties must be well known for fresh as well as irradiated fuel, and accurate prediction of fuel behavior must be possible to make for both normal operation and transient scenarios. Important parameters are known for fresh material but the behaviour of the fuel under irradiation is unknown particularly for low Th content. The irradiation campaign aims to widen the experience base to irradiated (Th,Pu)O{sub 2} fuel and (Th,U)O{sub 2} with low Th content and to confirm existing data for fresh fuel. The assumptions with respect to improved in-core fuel performance are confirmed by our preliminary irradiation test results, and our fuel manufacture trials so far indicate that both (Th,U)O{sub 2} and (Th,Pu)O{sub 2} fuels can be fabricated with existing technologies, which are possible to upscale to commercial volumes.

  5. Effects of irradiation on the thorium phosphate diphosphate ceramics and consequences on its dissolution

    NASA Astrophysics Data System (ADS)

    Tamain, C.; Özgümüs, A.; Dacheux, N.; Garrido, F.; Thomé, L.

    2006-06-01

    Thorium phosphate diphosphate samples (β-TPD), proposed as a ceramic for the long term immobilization of actinides, were externally irradiated with ions at several energies in order to simulate the self-irradiation as well as with γ-rays. The influence of the electronic energy loss was first investigated. XRD measurements showed a complete amorphization of the material at 1013 cm-2 of 840 MeV krypton while no significant structural change occurred at 5 × 1013 cm-2 of 410 MeV sulfur. The dissolution of raw and irradiated pellets was studied versus several parameters such as the amorphized fraction, the radiolytic species (as instance hydrogen peroxide) produced in situ in the leachate during irradiation, the temperature and the leachate acidity. The results obtained reveal a significant increase of the kinetics of dissolution for amorphized pellets compared to the raw ceramic.

  6. Production of medical isotopes from a thorium target irradiated by light charged particles up to 70 MeV

    NASA Astrophysics Data System (ADS)

    Duchemin, C.; Guertin, A.; Haddad, F.; Michel, N.; Métivier, V.

    2015-02-01

    The irradiation of a thorium target by light charged particles (protons and deuterons) leads to the production of several isotopes of medical interest. Direct nuclear reaction allows the production of Protactinium-230 which decays to Uranium-230 the mother nucleus of Thorium-226, a promising isotope for alpha radionuclide therapy. The fission of Thorium-232 produces fragments of interest like Molybdenum-99, Iodine-131 and Cadmium-115g. We focus our study on the production of these isotopes, performing new cross section measurements and calculating production yields. Our new sets of data are compared with the literature and the last version of the TALYS code.

  7. Production of medical isotopes from a thorium target irradiated by light charged particles up to 70 MeV.

    PubMed

    Duchemin, C; Guertin, A; Haddad, F; Michel, N; Métivier, V

    2015-02-07

    The irradiation of a thorium target by light charged particles (protons and deuterons) leads to the production of several isotopes of medical interest. Direct nuclear reaction allows the production of Protactinium-230 which decays to Uranium-230 the mother nucleus of Thorium-226, a promising isotope for alpha radionuclide therapy. The fission of Thorium-232 produces fragments of interest like Molybdenum-99, Iodine-131 and Cadmium-115g. We focus our study on the production of these isotopes, performing new cross section measurements and calculating production yields. Our new sets of data are compared with the literature and the last version of the TALYS code.

  8. Cross sections from proton irradiation of thorium at 800 MeV

    NASA Astrophysics Data System (ADS)

    Engle, Jonathan W.; Mashnik, Stepan G.; Weidner, John W.; Wolfsberg, Laura E.; Fassbender, Michael E.; Jackman, Kevin; Couture, Aaron; Bitteker, Leo J.; Ullmann, John L.; Gulley, Mark S.; Pillai, Chandra; John, Kevin D.; Birnbaum, Eva R.; Nortier, Francois M.

    2013-07-01

    Nuclear formation cross sections are reported for 65 nuclides produced from 800-MeV proton irradiation of thorium foils. These data are useful as benchmarks for computational predictions in the ongoing process of theoretical code development and also in the design of spallation-based radioisotope production currently being considered for multiple radiotherapeutic pharmaceutical agents. Measured data are compared with the predictions of three mcnp6 event generators and used to evaluate the potential for 800-MeV productions of radioisotopes of interest for medical radiotherapy. In only a few instances code predictions are discrepant from measured values by more than a factor of 2, demonstrating satisfactory predictive power across a large mass range. Similarly, agreement between measurements presented here and those previously reported is good, lending credibility to predictions of target yields and radioimpurities for high-energy accelerator-produced radionuclides.

  9. Simultaneous Separation of Actinium and Radium Isotopes from a Proton Irradiated Thorium Matrix.

    PubMed

    Mastren, Tara; Radchenko, Valery; Owens, Allison; Copping, Roy; Boll, Rose; Griswold, Justin R; Mirzadeh, Saed; Wyant, Lance E; Brugh, Mark; Engle, Jonathan W; Nortier, Francois M; Birnbaum, Eva R; John, Kevin D; Fassbender, Michael E

    2017-08-15

    A new method has been developed for the isolation of (223,224,225)Ra, in high yield and purity, from a proton irradiated (232)Th matrix. Herein we report an all-aqueous process using multiple solid-supported adsorption steps including a citrate chelation method developed to remove >99.9% of the barium contaminants by activity from the final radium product. A procedure involving the use of three columns in succession was developed, and the separation of (223,224,225)Ra from the thorium matrix was obtained with an overall recovery yield of 91 ± 3%, average radiochemical purity of 99.9%, and production yields that correspond to physical yields based on previously measured excitation functions.

  10. Simultaneous Separation of Actinium and Radium Isotopes from a Proton Irradiated Thorium Matrix

    DOE PAGES

    Mastren, Tara; Radchenko, Valery; Owens, Allison; ...

    2017-08-15

    A new method has been developed for the isolation of 223,224,225Ra, in high yield and purity, from a proton irradiated 232Th matrix. We report an all-aqueous process using multiple solid-supported adsorption steps including a citrate chelation method developed to remove >99.9% of the barium contaminants by activity from the final radium product. Moreover, we developed a procedure involving the use of three columns in succession, and the separation of 223,224,225Ra from the thorium matrix was obtained with an overall recovery yield of 91 ± 3%, average radiochemical purity of 99.9%, and production yields that correspond to physical yields based onmore » previously measured excitation functions.« less

  11. 800-MeV proton irradiation of thorium and depleted uranium targets

    SciTech Connect

    Russell, G.J.; Brun, T.O.; Pitcher, E.J.

    1995-10-01

    As part of the Los Alamos Fertile-to-Fissile-Conversion (FERFICON) program in the late 1980`s, thick targets of the fertile materials thorium and depleted uranium were bombarded by 800-MeV protons to produce the fissile materials {sup 233}U and {sup 239}Pu, respectively. The amount of {sup 233}U made was determined by measuring the {sup 233}Pa activity, and the yield of {sup 239}Pu was deduced by measuring the activity of {sup 239}Np. For the thorium target, 4 spallation products and 34 fission products were also measured. For the depleted uranium target, 3 spallation products and 16 fission products were also measured. The number of fissions in each target was deduced from fission product mass-yield curves. In actuality, axial distributions of the products were measured, and the distributions were then integrated over the target volume to obtain the total number of products for each reaction.

  12. Thermal-mechanical performance modeling of thorium-plutonium oxide fuel and comparison with on-line irradiation data

    NASA Astrophysics Data System (ADS)

    Insulander Björk, Klara; Kekkonen, Laura

    2015-12-01

    Thorium-plutonium Mixed OXide (Th-MOX) fuel is considered for use in light water reactors fuel due to some inherent benefits over conventional fuel types in terms of neutronic properties. The good material properties of ThO2 also suggest benefits in terms of thermal-mechanical fuel performance, but the use of Th-MOX fuel for commercial power production demands that its thermal-mechanical behavior can be accurately predicted using a well validated fuel performance code. Given the scant operational experience with Th-MOX fuel, no such code is available today. This article describes the first phase of the development of such a code, based on the well-established code FRAPCON 3.4, and in particular the correlations reviewed and chosen for the fuel material properties. The results of fuel temperature calculations with the code in its current state of development are shown and compared with data from a Th-MOX test irradiation campaign which is underway in the Halden research reactor. The results are good for fresh fuel, whereas experimental complications make it difficult to judge the adequacy of the code for simulations of irradiated fuel.

  13. Experimental Studies on the Self-Shielding Effect in Fissile Fuel Breeding Measurement in Thorium Oxide Pellets Irradiated with 14 MeV Neutrons

    NASA Astrophysics Data System (ADS)

    Mitul, Abhangi; Nupur, Jain; Rajnikant, Makwana; Sudhirsinh, Vala; Shrichand, Jakhar; K. Basu, T.; V. S. Rao, C.

    2013-02-01

    The 14 MeV neutrons produced in the D-T fusion reactions have the potential of breeding Uranium-233 fissile fuel from fertile material Thorium-232. In order to estimate the amount of U-233 produced, experiments are carried out by irradiating thorium dioxide pellets with neutrons produced from a 14 MeV neutron generator. The objective of the present work is to measure the reaction rates of 232Th + 1n → 233Th → 233Pa → 233U in different pellet thicknesses to study the self-shielding effects and adopt a procedure for correction. An appropriate assembly consisting of high-density polyethylene is designed and fabricated to slow down the high-energy neutrons, in which Thorium pellets are irradiated. The amount of fissile fuel (233U) produced is estimated by measuring the 312 keV gammas emitted by Protactinium-233 (half-life of 27 days). A calibrated High Purity Germanium (HPGe) detector is used to measure the gamma ray spectrum. The amount of 233U produced by Th232 (n, γ) is calculated using MCNP code. The self-shielding effect is evaluated by calculating the reaction rates for different foil thickness. MCNP calculation results are compared with the experimental values and appropriate correction factors are estimated for self-shielding of neutrons and absorption of gamma rays.

  14. Extraction of protactinium-233 and separation from thermal neutron-irradiated thorium-232 using crown ethers

    SciTech Connect

    Jalhoom, Moayyed G.; Mohammed, Dawood A.; Khalaf, Jumah S.

    2008-07-01

    A new method was developed for the extraction and separation of {sup 233}Pa from thermal neutron-irradiated {sup 232}Th. Solutions of Pa{sup 233} were prepared in LiCI-HCl solutions from which appreciable extraction was obtained using dibenzo-18-crown-6 in 1,2-dichloroethane. The effects of cavity size, substitutions on the crown ring, type of the organic solvent, and temperature on extraction are discussed. Very high separation factors were obtained for the pairs {sup 233}Pa/{sup 232}Th (>105), {sup 233}Pa/{sup 233}U (> 1000), and {sup 232}U/{sup 232}Th (>60). (authors)

  15. Cross-sections of residual nuclei from deuteron irradiation of thin thorium target at energy 7 GeV

    NASA Astrophysics Data System (ADS)

    Vespalec, Radek; Adam, Jindrich; Baldin, Anton Alexandrovich; Khushvaktov, Jurabek; Solnyshkin, Alexander Alexandrovich; Tsoupko-Sitnikov, Vsevolod Mikhailovich; Tyutyunikov, Sergey Ivanovich; Vrzalova, Jitka; Zavorka, Lukas; Zeman, Miroslav

    2017-09-01

    The residual nuclei yields are of great importance for the estimation of basic radiation-technology characteristics (like a total target activity, production of long-lived nuclides etc.) of accelerator driven systems planned for transmutation of spent nuclear fuel and for a design of radioisotopes production facilities. Experimental data are also essential for validation of nuclear codes describing various stages of a spallation reaction. Therefore, the main aim of this work is to add new experimental data in energy region of relativistic deuterons, as similar data are missing in nuclear databases. The sample made of thin natural thorium foil was irradiated at JINR Nuclotron accelerator with a deuteron beam of the total kinetic energy 7 GeV. Integral number of deuterons was determined with the use of aluminum activation detectors. Products of deuteron induced spallation reaction were qualified and quantified by means of gamma-ray spectroscopy method. Several important spectroscopic corrections were applied to obtain results of high accuracy. Experimental cumulative and independent cross-sections were determined for more than 80 isotopes including meta-stable isomers. The total uncertainty of results rarely exceeded 9%. Experimental results were compared with MCNP6.1 Monte-Carlo code predictions. Generally, experimental and calculated cross-sections are in a reasonably good agreement, with the exception of a few light isotopes in a fragmentation region, where the calculations are highly under-estimated. Measured data will be useful for future development of high-energy nuclear codes. After completion, final data will be added into the EXFOR database.

  16. Ion beam irradiation of lanthanum and thorium-doped yttrium titanates

    NASA Astrophysics Data System (ADS)

    Lian, J.; Zhang, F. X.; Peters, M. T.; Wang, L. M.; Ewing, R. C.

    2007-05-01

    Y2Ti2O7 pyrochlores doped with La have been sintered at 1373 K for 12 h with the designed compositions of the (LaxY1-x)2Ti2O7 system (x = 0, 0.08, 0.5, and 1), and the phase compositions were analyzed by X-ray diffraction. Limited amounts of La were incorporated into yttrium titanate pyrochlore structure for La-doped samples; while, the end member composition of La2Ti2O7 formed a layered perovskite structure. Ion beam-induced amorphization occurred for all compositions in the (LaxY1-x)2Ti2O7 binary under 1 MeV Kr2+ irradiation at room temperature, and the critical amorphization dose decreased with increasing amounts of La3+. The critical amorphization temperatures for Y2Ti2O7, (La0.162Y0.838)2Ti2O7 and La2Ti2O7 were determined to be ∼780, 890 and 920 K, respectively. Th4+ and Fe3+-doped yttrium titanate pyrochlores were synthesized at 1373 K by sintering Y2Ti2O7 with (ThO2 + Fe2O3). Pyrochlore structures and the chemical compositions were primarily identified by the X-ray diffraction and energy dispersive X-ray (EDX) measurements. The lattice parameter and the critical amorphization dose (1 MeV Kr2+ at room temperature) increase for yttrium titanate pyrochlores with the addition of Th. The increasing 'resistance' to amorphization with less La and greater Th and Fe contents for (Y1-xLax)2Ti2O7 and Y2Ti2O7-Fe2O3-ThO2 systems, respectively, are consistent with the changes in the average ionic radius ratio at the A-sites and B-sites. These results suggest that the addition of lanthanides and actinides (e.g., Th, U, or Pu) will affect the structural stability, as well as the radiation response behavior of the pyrochlore structure-type.

  17. Microstructure of RERTR DU-Alloys Irradiated with Krypton Ions

    SciTech Connect

    J. Gan; D. Keiser; D. Wachs; B. Miller; T. Allen; M. Kirk; J. Rest

    2009-11-01

    Fuel development for reduced enrichment research and test reactor (RERTR) program is tasked with the development of new low enrichment uranium fuels that can be employed to replace existing high enrichment uranium fuels currently used in many research and test reactors worldwide. Radiation stability of the interaction product formed at fuel-matrix interface has a strong impact on fuel performance. Three depleted uranium alloys are cast that consist of the following 5 phases of interest to be investigated: U(Si,Al)3, (U,Mo)(Si,Al)3, UMo2Al20, U6Mo4Al43 and UAl4. Irradiation of TEM disc samples with 500 keV Kr ions at 200?C to high doses up to ~100 dpa were conducted using an intermediate voltage electron microscope equipped with an ion accelerator. The irradiated microstructure of the 5 phases is characterized using transmission electron microscopy. The results will be presented and the implication of the observed irradiated microstructure on the fuel performance will be discussed.

  18. 225Ac and 223Ra production via 800 MeV proton irradiation of natural thorium targets.

    PubMed

    Weidner, J W; Mashnik, S G; John, K D; Ballard, B; Birnbaum, E R; Bitteker, L J; Couture, A; Fassbender, M E; Goff, G S; Gritzo, R; Hemez, F M; Runde, W; Ullmann, J L; Wolfsberg, L E; Nortier, F M

    2012-11-01

    Cross sections for the formation of (225,227)Ac, (223,225)Ra, and (227)Th via the proton bombardment of natural thorium targets were measured at a nominal proton energy of 800 MeV. No earlier experimental cross section data for the production of (223,225)Ra, (227)Ac and (227)Th by this method were found in the literature. A comparison of theoretical predictions with the experimental data shows agreement within a factor of two. Results indicate that accelerator-based production of (225)Ac and (223)Ra is a viable production method. Published by Elsevier Ltd.

  19. Application of ion exchange and extraction chromatography to the separation of actinium from proton-irradiated thorium metal for analytical purposes.

    PubMed

    Radchenko, V; Engle, J W; Wilson, J J; Maassen, J R; Nortier, F M; Taylor, W A; Birnbaum, E R; Hudston, L A; John, K D; Fassbender, M E

    2015-02-06

    Actinium-225 (t1/2=9.92d) is an α-emitting radionuclide with nuclear properties well-suited for use in targeted alpha therapy (TAT), a powerful treatment method for malignant tumors. Actinium-225 can also be utilized as a generator for (213)Bi (t1/2 45.6 min), which is another valuable candidate for TAT. Actinium-225 can be produced via proton irradiation of thorium metal; however, long-lived (227)Ac (t1/2=21.8a, 99% β(-), 1% α) is co-produced during this process and will impact the quality of the final product. Thus, accurate assays are needed to determine the (225)Ac/(227)Ac ratio, which is dependent on beam energy, irradiation time and target design. Accurate actinium assays, in turn, require efficient separation of actinium isotopes from both the Th matrix and highly radioactive activation by-products, especially radiolanthanides formed from proton-induced fission. In this study, we introduce a novel, selective chromatographic technique for the recovery and purification of actinium isotopes from irradiated Th matrices. A two-step sequence of cation exchange and extraction chromatography was implemented. Radiolanthanides were quantitatively removed from Ac, and no non-Ac radionuclidic impurities were detected in the final Ac fraction. An (225)Ac spike added prior to separation was recovered at ≥ 98%, and Ac decontamination from Th was found to be ≥ 10(6). The purified actinium fraction allowed for highly accurate (227)Ac determination at analytical scales, i.e., at (227)Ac activities of 1-100 kBq (27 nCi to 2.7 μCi).

  20. Interactions of secondary particles with thorium samples in the setup QUINTA irradiated with 6 GeV deuterons

    NASA Astrophysics Data System (ADS)

    Khushvaktov, J.; Adam, J.; Baldin, A. A.; Chilap, V. V.; Furman, V. I.; Sagimbaeva, F.; Solnyshkin, A. A.; Stegailov, V. I.; Tichy, P.; Tsoupko-Sitnikov, V. M.; Tyutyunnikov, S. I.; Vespalec, R.; Vrzalova, J.; Yuldashev, B. S.; Wagner, V.; Zavorka, L.; Zeman, M.

    2016-08-01

    The natural uranium assembly, QUINTA, was irradiated with 6 GeV deuterons. The 232Th samples were placed at the central axis of the setup QUINTA. The spectra of gamma rays emitted by the activated 232Th samples have been analysed and more than one hundred nuclei produced have been identified. For each of those products, reaction rates have been determined. The ratio of the weight of produced 233U to 232Th is presented. Experimental results were compared with the results of Monte Carlo simulations by FLUKA code.

  1. Thorium fueled reactor

    NASA Astrophysics Data System (ADS)

    Sipaun, S.

    2017-01-01

    Current development in thorium fueled reactors shows that they can be designed to operate in the fast or thermal spectrum. The thorium/uranium fuel cycle converts fertile thorium-232 into fissile uranium-233, which fissions and releases energy. This paper analyses the characteristics of thorium fueled reactors and discusses the thermal reactor option. It is found that thorium fuel can be utilized in molten salt reactors through many configurations and designs. A balanced assessment on the feasibility of adopting one reactor technology versus another could lead to optimized benefits of having thorium resource.

  2. Neutronics Design of a Thorium-Fueled Fission Blanket for LIFE (Laser Inertial Fusion-based Energy)

    SciTech Connect

    Powers, J; Abbott, R; Fratoni, M; Kramer, K; Latkowski, J; Seifried, J; Taylor, J

    2010-03-08

    The Laser Inertial Fusion-based Energy (LIFE) project at LLNL includes development of hybrid fusion-fission systems for energy generation. These hybrid LIFE engines use high-energy neutrons from laser-based inertial confinement fusion to drive a subcritical blanket of fission fuel that surrounds the fusion chamber. The fission blanket contains TRISO fuel particles packed into pebbles in a flowing bed geometry cooled by a molten salt (flibe). LIFE engines using a thorium fuel cycle provide potential improvements in overall fuel cycle performance and resource utilization compared to using depleted uranium (DU) and may minimize waste repository and proliferation concerns. A preliminary engine design with an initial loading of 40 metric tons of thorium can maintain a power level of 2000 MW{sub th} for about 55 years, at which point the fuel reaches an average burnup level of about 75% FIMA. Acceptable performance was achieved without using any zero-flux environment 'cooling periods' to allow {sup 233}Pa to decay to {sup 233}U; thorium undergoes constant irradiation in this LIFE engine design to minimize proliferation risks and fuel inventory. Vast reductions in end-of-life (EOL) transuranic (TRU) inventories compared to those produced by a similar uranium system suggest reduced proliferation risks. Decay heat generation in discharge fuel appears lower for a thorium LIFE engine than a DU engine but differences in radioactive ingestion hazard are less conclusive. Future efforts on development of thorium-fueled LIFE fission blankets engine development will include design optimization, fuel performance analysis work, and further waste disposal and nonproliferation analyses.

  3. Radionuclide Basics: Thorium

    EPA Pesticide Factsheets

    Thorium is a naturally occurring radioactive metal found at trace levels in soil, rocks, plants and animals. Thorium is used very little in industry, but can be found in heat-resistant alloys and paints and optical lenses.

  4. PRODUCTION OF THORIUM FLUORIDE

    DOEpatents

    Zachariasen, W.H.

    1959-08-11

    A process is presented for producing anhydrous thorium fluoride comprising the step of contacting a saturated aqueous solution of thorium nitrate with an aqueous solution of hydrofluoric acid having a concentration of about 45 to 50% by weight at a temperature above 70 deg C whereby anhydrous thorium fluoride precipitates.

  5. Safety and Regulatory Issues of the Thorium Fuel Cycle

    SciTech Connect

    Ade, Brian; Worrall, Andrew; Powers, Jeffrey; Bowman, Steve; Flanagan, George; Gehin, Jess

    2014-02-01

    Thorium has been widely considered an alternative to uranium fuel because of its relatively large natural abundance and its ability to breed fissile fuel (233U) from natural thorium (232Th). Possible scenarios for using thorium in the nuclear fuel cycle include use in different nuclear reactor types (light water, high temperature gas cooled, fast spectrum sodium, molten salt, etc.), advanced accelerator-driven systems, or even fission-fusion hybrid systems. The most likely near-term application of thorium in the United States is in currently operating light water reactors (LWRs). This use is primarily based on concepts that mix thorium with uranium (UO2 + ThO2), add fertile thorium (ThO2) fuel pins to LWR fuel assemblies, or use mixed plutonium and thorium (PuO2 + ThO2) fuel assemblies. The addition of thorium to currently operating LWRs would result in a number of different phenomenological impacts on the nuclear fuel. Thorium and its irradiation products have nuclear characteristics that are different from those of uranium. In addition, ThO2, alone or mixed with UO2 fuel, leads to different chemical and physical properties of the fuel. These aspects are key to reactor safety-related issues. The primary objectives of this report are to summarize historical, current, and proposed uses of thorium in nuclear reactors; provide some important properties of thorium fuel; perform qualitative and quantitative evaluations of both in-reactor and out-of-reactor safety issues and requirements specific to a thorium-based fuel cycle for current LWR reactor designs; and identify key knowledge gaps and technical issues that need to be addressed for the licensing of thorium LWR fuel in the United States.

  6. Qualification sous irradiation du crayon cea: de la conception des composants a l'irradiation d'assemblages en reacteur de puissance

    NASA Astrophysics Data System (ADS)

    Marin, Jean-François; Pillet, Claude; François, Bernard; Morize, Pierre; Petitgrand, Sylvie; Atabek, Rose-Marie; Houdaille, Brigitte

    1982-04-01

    Cet article résume les principaux résultats obtenus au CEA au cours des dix dernières années dans la conception, la qualification et la fabrication des différents éléments originaux constitutifs d'un assemblage de réacteur à eau pressurisée, notamment: l'oxyde UO 2 obtenu par le procédé du Double Cycle Inverse, la gaine en zircaloy 4 recris talllsée, la grille à ressort papillon, la structure à grilles coulissantes. Les etudes et essais hors-pile de comportement thermomécanique du crayon et thermohydraulique des composants de l'assemblage, les irradiations paramétriques de crayons jusqu'à une combustion massique élevée, la validation à partir d'examens aprés irradiation des principaux modèles introduits dans les calculs de conception, enfin l'introduction en réacteur prototype, puis en réacteur de puissance d'assemblages comportant ces différents éléments, constituent les principales étapes de ce développement.

  7. Nuclear and materials aspects of the thorium fuel cycle

    NASA Astrophysics Data System (ADS)

    Rodriguez, P.; Sundaram, C. V.

    1981-09-01

    This paper is an attempt to assess and review the materials aspects of the thorium fuel cycle. It starts with an examination of the nuclear aspects of the thorium fuel cycle, meant as an introduction for materials scientists and engineers who may not normally be familiar with the concepts and terms involved. After defining and describing the thorium and uranium fuel cycles, the reasons for the resurgence of interest in the thorium fuel cycle and the technical and economic considerations that support its early adoption are examined. The reactor physics and fissile economics aspects of the thorium and uranium cycles are then compared. The specific reactor types suitable for the adoption of the thorium cycle are briefly examined and described. Subsequent sections of the paper are devoted to a detailed discussion of the materials aspects of the thorium fuel cycle. Available information on fabrication, refabrication and irradiation performance of thorium-based fuels for light water reactors, heavy water reactors, high temperature gas-cooled reactors, molten salt breeder reactors and fast breeder reactors is critically reviewed and analysed. Materials problems related to cladding and structural materials are also discussed whenever these are unique to the thorium cycle.

  8. Combustible caramel pour reacteurs de recherche: Experience acquise en fabrication, controles et irradiation du coeur d'osiris

    NASA Astrophysics Data System (ADS)

    de Contenson, Ghislain; Foulquier, Henri; Trotabas, Maria; Vignesoult, Nicole; Cerles, Jean-Marie; Delafosse, Jacques

    1982-04-01

    L'un des aboutissements des différentes actions menées en France concernant la conception, la fabrication et le développement des combustibles nucléaires a été la mise au point par le CEA d'un combustible de type plaque (combustible CARAMEL) susceptible d'être adapté a différentes catégories de réacteurs à eau (réacteur de puissance, propulsion navale, chauffage urbain, pile de recherche). Ces travaux ont été couronnés par la réalisation de tout un coeur et des recharges du réacteur de recherche à hautes performances, Osiris, à Saclay. L'ancien combustible en alliage U Al fortement enrichi a eté remplacé par un combustible caramel de faible enrichissement (7%), non proliférant. Ce nouveau coeur fonctionne avec satisfaction, depuis janvier 1980. Après une brève description des caractéristiques du combustible caramel et de ses principaux avantages, on présente sa fabrication ainsi que l'ensemble des contrôles de qualité auxquels il est soumis. Le programme de qualification ainsi que les principaux résultáts qui en ont été tirés sont exposés. On décrit également le programme de suivi du combustible en pile dont le but est de s'assurer du bon comportement du combustible sous irradiation. Le bon fonctionnement d'Osiris, qui a terminé 11 cycles d'irradiation le 21 avril 1981, a permis de montrer le bien fondé des choix effectués et l'excellent comportement de l'élément combustible dans les conditions pourtant sévères d'un réacteur de recherche à hautes performances.

  9. THORIUM DISPERSION IN BISMUTH

    DOEpatents

    Bryner, J.S.

    1961-07-01

    The growth of thorium bismutaide particles, which are formed when thorium is suspended in liquid bismuth, is inhibited when the liquid metal suspension is being flowed through a reactor and through a heat exchanger in sequence. It involves the addition of as little as 1 part by weight of tellurium to 100 parts of thorium. This addition is sufficient to inhibit particle growth and agglomeration.

  10. SEPARATION OF URANIUM FROM THORIUM AND PROTACTINIUM

    DOEpatents

    Musgrave, W.K.R.

    1959-06-30

    This patent relates to the separation of uranium from thorium and protactinium; such mixtures of elements usually being obtained by neutron irradiation of thorium. The method of separating the constituents has been first to dissolve the mixture of elements in concertrated nitric acid and then to remove the protactinium by absorption on manganese dioxide and the uranium by solvent extraction with ether. Prior to now, comparatively large amounts of thorium were extracted with the uranium. According to the invention this is completely prevented by adding sodium diethyldithiocarbamate to the mixture of soluble nitrate salts. The organic salt has the effect of reacting only with the uranyl nitrate to form the corresponding uranyl salt which can then be selectively extracted from the mixture with amyl acetate.

  11. METHOD OF RECOVERING THORIUM

    DOEpatents

    Fisher, R.W.

    1957-12-10

    A method is described for recovering thorium from impurities found in a slag containing thorium and said impurities, comprising leaching a composition containing thorium with water, removing the water solution, treating the residue with hydrochloric acid, separating the solution from the insoluble residue, adjusting its acidity to 1 to 3 normal, adding oxalic acid, and thereafter separating the precipitated thorium oxalate digesting the residue from the hydrochloric acid treatment with a strong solution of sodium hydroxide at an elevated temperature, removing said solution and treating the insoluble residue with hydrochloric acid, separating the solution from the insoluble residue, adjusting the acidity of this solution to 1 to 3 normal, adding nitric acid to oxidize the iron present, adding oxalic acid and thereafter separating the thorium oxalate thus precipitated.

  12. Raman Spectroscopy for Analysis of Thorium Compounds

    SciTech Connect

    Su, Yin-Fong; Johnson, Timothy J.; Olsen, Khris B.

    2016-05-12

    The thorium fuel cycle is an alternative to the uranium fuel cycle in that when 232Th is irradiated with neutrons it is converted to 233U, another fissile isotope. There are several chemical forms of thorium which are used in the Th fuel cycle. Recently, Raman spectroscopy has become a very portable and facile analytical technique useful for many applications, including e.g. determining the chemical composition of different materials such as for thorium compounds. The technique continues to improve with the development of ever-more sensitive instrumentation and better software. Using a laboratory Fourier-transform (FT)-Raman spectrometer with a 785 nm wavelength laser, we were able to obtain Raman spectra from a series of thorium-bearing compounds of unknown origin. These spectra were compared to the spectra of in-stock-laboratory thorium compounds including ThO2, ThF4, Th(CO3)2 and Th(C2O4)2. The unknown spectra showed very good agreement to the known standards, demonstrating the applicability of Raman spectroscopy for detection and identification of these nuclear materials.

  13. Thorium Energy Futures

    SciTech Connect

    Peggs, Stephen; Roser, Thomas; Parks, G; Lindroos, Mats; Seviour, Rebecca; Henderson, Stuart; Barlow, R; Cywinski, R; Biarrote, J -L; Norlin, A; Ashley, V; Ashworth, R; Hutton, Andrew; Owen, H; McIntyre, Peter; Kelly, J

    2012-07-01

    The potential for thorium as an alternative or supplement to uranium in fission power generation has long been recognised, and several reactors, of various types, have already operated using thorium-based fuels. Accelerator Driven Subcritical (ADS) systems have benefits and drawbacks when compared to conventional critical thorium reactors, for both solid and molten salt fuels. None of the four options - liquid or solid, with or without an accelerator - can yet be rated as better or worse than the other three, given today's knowledge. We outline the research that will be necessary to lead to an informed choice.

  14. Minerals yearbook, 1988: Thorium

    SciTech Connect

    Hedrick, J.B.

    1988-01-01

    Mine production of monazite, the principal source of thorium, decreased slightly in 1988. Associated Minerals (USA) Inc. was the only domestic monazite producer. Monazite produced in the United States was exported, and the thorium products used domestically were derived from imported materials, existing company stocks, and thorium nitrate released from the National Defense Stockpile. Major nonenergy uses were in refractory applications, ceramics, and mantles for incandescent lanterns. The only energy use of thorium in the United States was in the high-temperature gas-cooled (HTGC) nuclear reactor at Fort St. Vrain, CO. Topics discussed in the report include domestic data coverage, legislation and government programs, domestic production, consumption and uses, stocks, prices, foreign trade, world capacity, and world review--(Australia, Brazil, Madagascar, Mozambique).

  15. Thorium metabolism and dosimetry

    SciTech Connect

    Johnson, J.R.; Hill, R.L.; Birchall, A.; Jarvis, N.S.

    1994-07-01

    Thorium occurs widely in nature, and has been used in medicine, industry, and advanced nuclear fuel cycles. Despite many studies, there still remains uncertainty in the dosimetry of Th, particularly that associated with the Th-232 decay chain. This presentation reviews past and current uses of thorium, and describes the residual difficulties involved with monitoring methods and calculations used in both environmental and occupational exposure evaluations.

  16. ZIRCONIUM-CLADDING OF THORIUM

    DOEpatents

    Beaver, R.J.

    1961-11-21

    A method of cladding thorium with zirconium is described. The quality of the bond achieved between thorium and zirconium by hot-rolling is improved by inserting and melting a thorium-zirconium alloy foil between the two materials prior to rolling. (AEC)

  17. Thorium in mineral products.

    PubMed

    Collier, D E; Brown, S A; Blagojevic, N; Soldenhoff, K H; Ring, R J

    2001-01-01

    Many ores contain low levels of thorium. When these ores are processed, the associated radioactivity can be found in mineral concentrates, intermediates and final products. There is an incentive for industries to remove radioactivity from mineral products to allow the movement and sale of these materials, both nationally and internationally, without the need for licensing. Control of thorium in various products involves the development and optimisation of process steps to be able to meet product specifications. The Australian Nuclear Science and Technology Organisation (ANSTO) has undertaken a range of R & D programmes targeting the treatment of thorium-bearing minerals. This paper discusses the application of a microprobe technique for siting radioactivity in zircon and ilmenite and the problems experienced in measuring the concentrations in solid rare earth products.

  18. Local Electrochemical Deposition of Thorium on SiO2/Si(111) Surface

    NASA Astrophysics Data System (ADS)

    Troyan, V. I.; Borisyuk, P. V.; Lebedinskii, Yu. Yu.; Vasiliev, O. S.

    The paper presents the results of the study of local formation of thorium oxide coatings on SiO2/Si(111) surface by electrochemical deposition. It was found that the electrochemical deposition of thorium atoms from thorium nitrate solution of Th(NO3)4 with the presence of water on silicon surface results in local formation of thorium compounds. The results of surface analysis by local XPS indicate that these compounds represent a thorium-, silicon-, oxygen- and carbon-based compounds. After 6 hours annealing at 600 °C at atmosphere carbon pulled completely, and the cluster formed film consists of oxygen and thorium only. It was shown that this system can be promising for further research of nuclear low-lying isomeric transition in 229Th isotope when irradiated by an electron beam.

  19. SOLVENT EXTRACTION PROCESS FOR THE SEPARATION OF URANIUM AND THORIUM FROM PROTACTINIUM AND FISSION PRODUCTS

    DOEpatents

    Rainey, R.H.; Moore, J.G.

    1962-08-14

    A liquid-liquid extraction process was developed for recovering thorium and uranium values from a neutron irradiated thorium composition. They are separated from a solvent extraction system comprising a first end extraction stage for introducing an aqueous feed containing thorium and uranium into the system consisting of a plurality of intermediate extractiorr stages and a second end extractron stage for introducing an aqueous immiscible selective organic solvent for thorium and uranium in countercurrent contact therein with the aqueous feed. A nitrate iondeficient aqueous feed solution containing thorium and uranium was introduced into the first end extraction stage in countercurrent contact with the organic solvent entering the system from the second end extraction stage while intro ducing an aqueous solution of salting nitric acid into any one of the intermediate extraction stages of the system. The resultant thorium and uranium-laden organic solvent was removed at a point preceding the first end extraction stage of the system. (AEC)

  20. PLUTONIUM-THORIUM ALLOYS

    DOEpatents

    Schonfeld, F.W.

    1959-09-15

    New plutonium-base binary alloys useful as liquid reactor fuel are described. The alloys consist of 50 to 98 at.% thorium with the remainder plutonium. The stated advantages of these alloys over unalloyed plutonium for reactor fuel use are easy fabrication, phase stability, and the accompanying advantuge of providing a means for converting Th/sup 232/ into U/sup 233/.

  1. Microstructure of RERTR Du-Alloys Irradiated with Krypton Ions up to 100 dpa

    SciTech Connect

    J. Gan; D. D. Keiser, Jr.; D. M. Wachs; B. D. Miller; T. R. Allen; M. Kirk; J. Rest

    2011-04-01

    The radiation stability of the interaction product formed at the fuel–matrix interface of research reactor dispersion fuels, under fission-product bombardment, has a strong impact on fuel performance. Three depleted uranium alloys were cast that consisted of the following five phases to be investigated: U(Si, Al)3, (U, Mo)(Si, Al)3, UMo2Al20, U6Mo4Al43, and UAl4. Irradiation of transmission electron microscopy (TEM) disc samples with 500-keV Kr ions at 200 °C to doses up to 100 displacements per atom (dpa) were conducted using a 300-keV electron microscope equipped with an ion accelerator. TEM results show that the U(Si, Al)3 and UAl4 phases remain crystalline at 100 dpa without forming voids. The (U, Mo)(Si, Al)3 and UMo2Al20 phases become amorphous at 1 and 2 dpa, respectively, and show no evidence of voids at 100 dpa. The U6Mo4Al43 phase goes to amorphous at less than 1 dpa and reveals high density voids at 100 dpa.

  2. CATALYTIC RECOMBINATION OF RADIOLYTIC GASES IN THORIUM OXIDE SLURRIES

    DOEpatents

    Morse, L.E.

    1962-08-01

    A method for the coinbination of hydrogen and oxygen in aqueous thorium oxide-uranium oxide slurries is described. A small amount of molybdenum oxide catalyst is provided in the slurry. This catalyst is applicable to the recombination of hydrogen and/or deuterium and oxygen produced by irradiation of the slurries in nuclear reactors. (AEC)

  3. ELECTROLYSIS OF THORIUM AND URANIUM

    DOEpatents

    Hansen, W.N.

    1960-09-01

    An electrolytic method is given for obtaining pure thorium, uranium, and thorium-uranium alloys. The electrolytic cell comprises a cathode composed of a metal selected from the class consisting of zinc, cadmium, tin, lead, antimony, and bismuth, an anode composed of at least one of the metals selected from the group consisting of thorium and uranium in an impure state, and an electrolyte composed of a fused salt containing at least one of the salts of the metals selected from the class consisting of thorium, uranium. zinc, cadmium, tin, lead, antimony, and bismuth. Electrolysis of the fused salt while the cathode is maintained in the molten condition deposits thorium, uranium, or thorium-uranium alloys in pure form in the molten cathode which thereafter may be separated from the molten cathode product by distillation.

  4. SEPARATION OF URANIUM FROM THORIUM

    DOEpatents

    Hellman, N.N.

    1959-07-01

    A process is presented for separating uranium from thorium wherein the ratio of thorium to uranium is between 100 to 10,000. According to the invention the thoriumuranium mixture is dissolved in nitric acid, and the solution is prepared so as to obtain the desired concentration within a critical range of from 4 to 8 N with regard to the total nitrate due to thorium nitrate, with or without nitric acid or any nitrate salting out agent. The solution is then contacted with an ether, such as diethyl ether, whereby uranium is extracted into ihe organic phase while thorium remains in the aqueous phase.

  5. SEPARATION OF THORIUM FROM URANIUM

    DOEpatents

    Bane, R.W.

    1959-09-01

    A description is given for the separation of thorium from uranium by forming an aqueous acidic solution containing ionic species of thorium, uranyl uranium, and hydroxylamine, flowing the solution through a column containing the phenol-formaldehyde type cation exchange resin to selectively adsorb substantially all the thorium values and a portion of the uranium values, flowing a dilute solution of hydrochloric acid through the column to desorb the uranium values, and then flowing a dilute aqueous acidic solution containing an ion, such as bisulfate, which has a complexing effect upon thortum through the column to desorb substantially all of the thorium.

  6. PROCESS FOR DECONTAMINATING THORIUM AND URANIUM WITH RESPECT TO RUTHENIUM

    DOEpatents

    Meservey, A.A.; Rainey, R.H.

    1959-10-20

    The control of ruthenium extraction in solvent-extraction processing of neutron-irradiated thorium is presented. Ruthenium is rendered organic-insoluble by the provision of sulfite or bisulfite ions in the aqueous feed solution. As a result the ruthenium remains in the aqueous phase along with other fission product and protactinium values, thorium and uranium values being extracted into the organic phase. This process is particularly applicable to the use of a nitrate-ion-deficient aqueous feed solution and to the use of tributyl phosphate as the organic extractant.

  7. Analysis of key safety metrics of thorium utilization in LWRs

    DOE PAGES

    Ade, Brian J.; Bowman, Stephen M.; Worrall, Andrew; ...

    2016-04-08

    Here, thorium has great potential to stretch nuclear fuel reserves because of its natural abundance and because it is possible to breed the 232Th isotope into a fissile fuel (233U). Various scenarios exist for utilization of thorium in the nuclear fuel cycle, including use in different nuclear reactor types (e.g., light water, high-temperature gas-cooled, fast spectrum sodium, and molten salt reactors), along with use in advanced accelerator-driven systems and even in fission-fusion hybrid systems. The most likely near-term application of thorium in the United States is in currently operating light water reactors (LWRs). This use is primarily based on conceptsmore » that mix thorium with uranium (UO2 + ThO2) or that add fertile thorium (ThO2) fuel pins to typical LWR fuel assemblies. Utilization of mixed fuel assemblies (PuO2 + ThO2) is also possible. The addition of thorium to currently operating LWRs would result in a number of different phenomenological impacts to the nuclear fuel. Thorium and its irradiation products have different nuclear characteristics from those of uranium and its irradiation products. ThO2, alone or mixed with UO2 fuel, leads to different chemical and physical properties of the fuel. These key reactor safety–related issues have been studied at Oak Ridge National Laboratory and documented in “Safety and Regulatory Issues of the Thorium Fuel Cycle” (NUREG/CR-7176, U.S. Nuclear Regulatory Commission, 2014). Various reactor analyses were performed using the SCALE code system for comparison of key performance parameters of both ThO2 + UO2 and ThO2 + PuO2 against those of UO2 and typical UO2 + PuO2 mixed oxide fuels, including reactivity coefficients and power sharing between surrounding UO2 assemblies and the assembly of interest. The decay heat and radiological source terms for spent fuel after its discharge from the reactor are also presented. Based on this evaluation, potential impacts on safety requirements and identification of

  8. Analysis of key safety metrics of thorium utilization in LWRs

    SciTech Connect

    Ade, Brian J.; Bowman, Stephen M.; Worrall, Andrew; Powers, Jeffrey

    2016-04-08

    Here, thorium has great potential to stretch nuclear fuel reserves because of its natural abundance and because it is possible to breed the 232Th isotope into a fissile fuel (233U). Various scenarios exist for utilization of thorium in the nuclear fuel cycle, including use in different nuclear reactor types (e.g., light water, high-temperature gas-cooled, fast spectrum sodium, and molten salt reactors), along with use in advanced accelerator-driven systems and even in fission-fusion hybrid systems. The most likely near-term application of thorium in the United States is in currently operating light water reactors (LWRs). This use is primarily based on concepts that mix thorium with uranium (UO2 + ThO2) or that add fertile thorium (ThO2) fuel pins to typical LWR fuel assemblies. Utilization of mixed fuel assemblies (PuO2 + ThO2) is also possible. The addition of thorium to currently operating LWRs would result in a number of different phenomenological impacts to the nuclear fuel. Thorium and its irradiation products have different nuclear characteristics from those of uranium and its irradiation products. ThO2, alone or mixed with UO2 fuel, leads to different chemical and physical properties of the fuel. These key reactor safety–related issues have been studied at Oak Ridge National Laboratory and documented in “Safety and Regulatory Issues of the Thorium Fuel Cycle” (NUREG/CR-7176, U.S. Nuclear Regulatory Commission, 2014). Various reactor analyses were performed using the SCALE code system for comparison of key performance parameters of both ThO2 + UO2 and ThO2 + PuO2 against those of UO2 and typical UO2 + PuO2 mixed oxide fuels, including reactivity coefficients and power sharing between surrounding UO2 assemblies and the assembly of interest. The decay heat and

  9. PRETREATING THORIUM FOR ELECTROPLATING

    DOEpatents

    Beach, J.G.; Schaer, G.R.

    1959-07-28

    A method is presented for pretreating a thorium surface prior to electroplating the surface. The pretreatment steps of the invention comprise cleaning by vapor blasting the surface, anodically pickling in a 5 to 15% by volume aqueous hydrochloric acid bath with a current of 125 to 250 amp/sq ft for 3 to 5 min at room temperature, chemically pickling the surface in a 5 to 15% by volume of aqueous sulfuric acid for 3 to 5 min at room temperature, and rinsing the surface with water.

  10. METHOD FOR PRODUCING THORIUM TETRACHLORIDE

    DOEpatents

    Mason, E.A.; Cobb, C.M.

    1960-03-15

    A process for producing thorium tetrachloride from thorium concentrate comprises reacting thorium concentrates with a carbonaceous reducing agent in excess of 0.05 part by weight per part of thoriferous concentrate at a temperature in excess of 1300 deg C, cooling and comminuting the mass, chlorinating the resulting comminuting mass by suspending in a gaseous chlorinating agent in a fluidized reactor at a temperatare maintained between about l85 deg C and 770 deg C, and removing the resulting solid ThCl/sub 4/ from the reaction zone.

  11. PLUTONIUM PURIFICATION PROCESS EMPLOYING THORIUM PYROPHOSPHATE CARRIER

    DOEpatents

    King, E.L.

    1959-04-28

    The separation and purification of plutonium from the radioactive elements of lower atomic weight is described. The process of this invention comprises forming a 0.5 to 2 M aqueous acidffc solution containing plutonium fons in the tetravalent state and elements with which it is normally contaminated in neutron irradiated uranium, treating the solution with a double thorium compound and a soluble pyrophosphate compound (Na/sub 4/P/sub 2/O/sub 7/) whereby a carrier precipitate of thorium A method is presented of reducing neptunium and - trite is advantageous since it destroys any hydrazine f so that they can be removed from solutions in which they are contained is described. In the carrier precipitation process for the separation of plutonium from uranium and fission products including zirconium and columbium, the precipitated blsmuth phosphate carries some zirconium, columbium, and uranium impurities. According to the invention such impurities can be complexed and removed by dissolving the contaminated carrier precipitate in 10M nitric acid, followed by addition of fluosilicic acid to about 1M, diluting the solution to about 1M in nitric acid, and then adding phosphoric acid to re-precipitate bismuth phosphate carrying plutonium.

  12. A fluorimetric study of the thorium-morin system

    USGS Publications Warehouse

    Milkey, Robert G.; Fletcher, Mary H.

    1956-01-01

    Thorium reacts with morin to yield a yellow complex that fluoresces when irradiated with ultraviolet light. The effect on the fluorescence of such variable as concentration of acid, alcohol, thorium, morin, and complex; time, temperature, and wavelength of exciting light are studied to determine experimental conditions yielding maximum fluorescence. The effects of Zr4+, Al3+, Fe3+, Ca2+, and La3+ are discussed. The fundamental relationships between light absorption and fluorescence are expressed in a general equation which applied to a three-component system when the fluorescence is measured in a transmission-type fluorimeter. This general equation is used to obtain an expression for the fluorescence of the thorium-morin system. Equations, derived from experimental data, related both the fraction of thorium reacted to form complex and the fraction of unquenched fluorescence to the concentration of uncombined morin. These functions, when combined with the general equation, give an expression which relates the total net fluorescence to the amount of uncombined morin in the solution. This last equation can be used to determine the one region for the concentration of uncombined morin that gives maximum sensitivity for the system. Calculated standard curves are in excellent agreement with experimental curves.

  13. Comparison of the radiological hazard of thorium and uranium spent fuels from VVER-1000 reactor

    NASA Astrophysics Data System (ADS)

    Frybort, Jan

    2014-11-01

    Thorium fuel is considered as a viable alternative to the uranium fuel used in the current generation of nuclear power plants. Switch from uranium to thorium means a complete change of composition of the spent nuclear fuel produced as a result of the fuel depletion during operation of a reactor. If the Th-U fuel cycle is implemented, production of minor actinides in the spent fuel is negligible. This is favourable for the spent fuel disposal. On the other hand, thorium fuel utilisation is connected with production of 232U, which decays via several alpha decays into a strong gamma emitter 208Tl. Presence of this nuclide might complicate manipulations with the irradiated thorium fuel. Monte-Carlo computation code MCNPX can be used to simulate thorium fuel depletion in a VVER-1000 reactor. The calculated actinide composition will be analysed and dose rate from produced gamma radiation will be calculated. The results will be compared to the reference uranium fuel. Dependence of the dose rate on time of decay after the end of irradiation in the reactor will be analysed. This study will compare the radiological hazard of the spent thorium and uranium fuel handling.

  14. Drying characteristics of thorium fuel corrosion products

    NASA Astrophysics Data System (ADS)

    Smith, R.-E. Lords

    2004-07-01

    The open literature and accessible US Department of Energy-sponsored reports were reviewed for the dehydration and rehydration characteristics of potential corrosion products from thorium metal and thorium oxide nuclear fuels. Mixed oxides were not specifically examined unless data were given for performance of mixed thorium-uranium fuels. Thorium metal generally corrodes to thorium oxide. Physisorbed water is readily removed by heating to approximately 200 °C. Complete removal of chemisorbed water requires heating above 1000 °C. Thorium oxide adsorbs water well in excess of the amount needed to cover the oxide surface by chemisorption. The adsorption of water appears to be a surface phenomenon; it does not lead to bulk conversion of the solid oxide to the hydroxide. Adsorptive capacity depends on both the specific surface area and the porosity of the thorium oxide. Heat treatment by calcination or sintering reduces the adsorption capacity substantially from the thorium oxide produced by metal corrosion.

  15. THORIUM OXALATE-URANYL ACETATE COUPLED PROCEDURE FOR THE SEPARATION OF RADIOACTIVE MATERIALS

    DOEpatents

    Gofman, J.W.

    1959-08-11

    The recovery of fission products from neutronirradiated uranium is described. The neutron-irradiated uranium is dissolved in acid and thorium oxalate is precipitated in ihe solution formed, whereby the fission products are carried on the thorium oxalate. The separated thorium oxalate precipitate is then dissolved in an aqueous oxalate solution and the solution formed is acidified, limiting ihe excess acidity to a maximum of 2 N, whereby thorium oxalate precipitates and carries lanthanum-rareearth- and alkaline-earth-metal fission products while the zirconium-fission-product remains in solution. This precipitate, too, is dissolved in an aqaeous oxalate solution at elevated temperature, and lanthanum-rare-earth ions are added to the solution whereby lanthanum-rare-earth oxalate forms and the lanthanum-rare-earth-type and alkalineearth-metal-type fission products are carried on the oxalate. The precipitate is separated from the solution.

  16. Upregulation of Beclin-1 expression in DU-145 cells following low-frequency ultrasound irradiation combined with microbubbles

    PubMed Central

    WANG, YU; CHEN, YI-NI; ZHANG, WEI; YANG, YU; SHEN, E.; HU, BING

    2015-01-01

    Castration-resistant prostate cancer (PCa) is difficult to treat. Autophagy, which is an evolutionarily conserved mechanism, plays an important role in cancer development. The balance between cell death and survival in different stages varies in cancer development. The role of autophagy in PCa development has not yet been fully elucidated. Ultrasound may be of value in the treatment of PCa. The aim of the present study was to investigate the association between autophagy and ultrasound combined with microbubbles. The MTT assay was used to evaluate cell viability. Autophagy was observed by transmission electron microscopy. Reverse transcription-polymerase chain reaction and western blot analysis were used to assess the expression of autophagy-related genes. The results revealed that cell viability was significantly reduced by ultrasound combined with microbubbles in DU145 PCa cells. The present study demonstrated that ultrasound combined with microbubbles induced autophagy and autophagy-related DU-145 cell death. Notably, these findings highlighted additional mechanisms that suggest the potential of ultrasound-modulated autophagy as a novel therapeutic strategy for PCa. PMID:26622876

  17. Mineral resource of the month: thorium

    USGS Publications Warehouse

    ,

    2009-01-01

    This article provides information on thorium. Thorium is a natural radioactive element that can be found with other minerals. It can be used to generate power, produce light and transmit energy. Thorium has a potential to be used as a nuclear fuel. This element was discovered by Swedish chemist and mineralogist Jóns Jakob Berzelius in 1828.

  18. SEPARATION PROCESS FOR THORIUM SALTS

    DOEpatents

    Bridger, G.L.; Whatley, M.E.; Shaw, K.G.

    1957-12-01

    A process is described for the separation of uranium, thorium, and rare earths extracted from monazite by digesting with sulfuric acid. By carefully increasing the pH of the solution, stepwise, over the range 0.8 to 5.5, a series of selective precipitations will be achieved, with the thorium values coming out at lower pH, the rare earths at intermediate pH and the uranium last. Some mixed precipitates will be obtained, and these may be treated by dissolving in HNO/sub 3/ and contacting with dibutyl phosphate, whereby thorium or uranium are taken up by the organic phase while the rare earths preferentially remain in the aqueous solution.

  19. Experimental study on the thorium-loaded accelerator-driven system at the Kyoto Univ. critical assembly

    SciTech Connect

    Pyeon, C. H.; Yagi, T.; Lim, J. Y.; Misawa, T.

    2012-07-01

    The experimental study on the thorium-loaded accelerator-driven system (ADS) is conducted in the Kyoto Univ. Critical Assembly (KUCA). The experiments are carried out in both the critical and subcritical states for attaining the reaction rates of the thorium capture and fission reactions. In the critical system, the thorium plate irradiation experiment is carried out for the thorium capture and fission reactions. From the results of the measurements, the thorium fission reactions are obtained apparently in the critical system, and the C/E values of reaction rates show the accuracy of relative difference of about 30%. In the ADS experiments with 14 MeV neutrons and 100 MeV protons, the subcritical experiments are carried out in the thorium-loaded cores to obtain the capture reaction rates through the measurements of {sup 115}In(n, {gamma}){sup 116m}In reactions. The results of the experiments reveal the difference between the reaction rate distributions for the change in not only the neutron spectrum but also the external neutron source. The comparison between the measured and calculated reaction rate distributions demonstrates a discrepancy of the accuracy of reaction rate analyses of thorium capture reactions through the thorium-loaded ADS experiments with 14 MeV neutrons. Hereafter, kinetic experiments are planned to be carried out to deduce the delayed neutron decay constants and subcriticality using the pulsed neutron method. (authors)

  20. Etude de la migration des interstitiels dans des austenites Fe, Cr (18), Ni (14) pures et industrielles par irradiation dans un microscope a tres haute tension: Role du carbone et du titane

    NASA Astrophysics Data System (ADS)

    Housseau, N.; Pelissier, J.

    1983-12-01

    Nous avons étudié le rôle des impurtés (C ou Ti) dans la condensation et la migration des défauts interstitiels. Les échantillons étudiés sont des aciers austénitiques: (a) acier de synthèse de haute pureté (Cr 18, Ni 14, Fe) avec ou sans carbone; (b) acier industriel avec C (800 ppm) ou Ti (0,45%). Les échantillons ont été irradiés dans un microscope à très haute tension aux doses allant de 10 -4 jusqu'à 10 -1 dpa aux températures de 300°C à 400°C. Dans de telles conditions les défauts observés sont des boucles interstitielles. L'étude de la variation de l'épaisseur de la zone dénudée près du bord de la lame mince en fonction de la température nous a permis d'évaluer l'énergie de migration effective de l'interstitiel dans ces alliages. Dans l'austénite de synthèse carburée ou non sa valeur est de 0.8 eV. Dans l'acier industriel au titane carburé ou non on obtient 2.0 eV. Nous n'avons pas observé d'effet lié au carbone. L'examen de la densité de boucles à saturation dans les divers aciers suggère une forte énergie de liaison interstitiel-titane. Cette énergie de liaison, si l'ont admet que le titane est la seule impureté agissante du système, peut être estimée à 1.2 eV.

  1. First-principles study of point defects in thorium carbide

    NASA Astrophysics Data System (ADS)

    Pérez Daroca, D.; Jaroszewicz, S.; Llois, A. M.; Mosca, H. O.

    2014-11-01

    Thorium-based materials are currently being investigated in relation with their potential utilization in Generation-IV reactors as nuclear fuels. One of the most important issues to be studied is their behavior under irradiation. A first approach to this goal is the study of point defects. By means of first-principles calculations within the framework of density functional theory, we study the stability and formation energies of vacancies, interstitials and Frenkel pairs in thorium carbide. We find that C isolated vacancies are the most likely defects, while C interstitials are energetically favored as compared to Th ones. These kind of results for ThC, to the best authors' knowledge, have not been obtained previously, neither experimentally, nor theoretically. For this reason, we compare with results on other compounds with the same NaCl-type structure.

  2. Point defects in thorium nitride: A first-principles study

    NASA Astrophysics Data System (ADS)

    Pérez Daroca, D.; Llois, A. M.; Mosca, H. O.

    2016-11-01

    Thorium and its compounds (carbides and nitrides) are being investigated as possible materials to be used as nuclear fuels for Generation-IV reactors. As a first step in the research of these materials under irradiation, we study the formation energies and stability of point defects in thorium nitride by means of first-principles calculations within the framework of density functional theory. We focus on vacancies, interstitials, Frenkel pairs and Schottky defects. We found that N and Th vacancies have almost the same formation energy and that the most energetically favorable defects of all studied in this work are N interstitials. These kind of results for ThN, to the best authors' knowledge, have not been obtained previously, neither experimentally, nor theoretically.

  3. Electrotransport purification of thorium under low pressure conditions

    NASA Technical Reports Server (NTRS)

    Schmidt, F. A.; Lunde, B. K.; Outlaw, R. A.

    1979-01-01

    It was demonstrated that the ultrapurification of refractory metals by electrotransport refining could best be accomplished in the noncontaminating environment of an orbiting low density materials laboratory such as the Molecular Shield Device. Refining experiments were performed at 2 x 10 to the -12th Torr which resulted in the preparation of small quantities of the World's purest thorium metal. The microgravity occurring in orbit was simulated electromagnetically and shown to be advantageous in eliminating grain-sliding caused by the plastic deformation of the sample at high temperature. The electrotransport sample assembly was tested in several environments including simulated solar irradiation, coldness and darkness and under various pressure conditions. Ultrapure single crystals of alpha thorium were also prepared and characterized. Laboratory electronics for the experiment were developed and a totally automatic control system was used to heat the specimens.

  4. Electrotransport purification of thorium under low pressure conditions

    NASA Technical Reports Server (NTRS)

    Schmidt, F. A.; Lunde, B. K.; Outlaw, R. A.

    1979-01-01

    It was demonstrated that the ultrapurification of refractory metals by electrotransport refining could best be accomplished in the noncontaminating environment of an orbiting low density materials laboratory such as the Molecular Shield Device. Refining experiments were performed at 2 x 10 to the -12th Torr which resulted in the preparation of small quantities of the World's purest thorium metal. The microgravity occurring in orbit was simulated electromagnetically and shown to be advantageous in eliminating grain-sliding caused by the plastic deformation of the sample at high temperature. The electrotransport sample assembly was tested in several environments including simulated solar irradiation, coldness and darkness and under various pressure conditions. Ultrapure single crystals of alpha thorium were also prepared and characterized. Laboratory electronics for the experiment were developed and a totally automatic control system was used to heat the specimens.

  5. Thorium Fuel Cycle Option Screening in the United States

    SciTech Connect

    Taiwo, Temitope A.; Kim, Taek K.; Wigeland, Roald A.

    2016-05-01

    As part of a nuclear fuel cycle Evaluation and Screening (E&S) study, a wide-range of thorium fuel cycle options were evaluated and their performance characteristics and challenges to implementation were compared to those of other nuclear fuel cycle options based on criteria specified by the Nuclear Energy Office of the U.S. Department of Energy (DOE). The evaluated nuclear fuel cycles included the once-through, limited, and continuous recycle options using critical or externally-driven nuclear energy systems. The E&S study found that the continuous recycle of 233U/Th in fuel cycles using either thermal or fast reactors is an attractive promising fuel cycle option with high effective fuel resource utilization and low waste generation, but did not perform quite as well as the continuous recycle of Pu/U using a fast critical system, which was identified as one of the most promising fuel cycle options in the E&S study. This is because compared to their uranium counterparts the thorium-based systems tended to have higher radioactivity in the short term (about 100 years post irradiation) because of differences in the fission product yield curves, and in the long term (100,000 years post irradiation) because of the decay of 233U and daughters, and because of higher mass flow rates due to lower discharge burnups. Some of the thorium-based systems also require enriched uranium support, which tends to be detrimental to resource utilization and waste generation metrics. Finally, similar to the need for developing recycle fuel fabrication, fuels separations and fast reactors for the most promising options using Pu/U recycle, the future thorium-based fuel cycle options with continuous recycle would also require such capabilities, although their deployment challenges are expected to be higher since such facilities have not been developed in the past to a comparable level of maturity for Th-based systems.

  6. Thorium Diffusion in Monazite

    NASA Astrophysics Data System (ADS)

    Cherniak, D. J.

    2006-05-01

    Diffusion of thorium has been characterized in synthetic monazite under dry conditions. The synthetic monazites (either pure CePO4, NdPO4, or a mixed LREE phosphate containing Ce, Nd, and Sm) were grown via a Na2CO3-MoO3 flux method. The source of diffusant for the experiments were either synthesized ThSiO4 or CaTh(PO4)2 powders. Experiments were performed by placing source and monazite in Pt capsules and annealing capsules in 1 atm furnaces for times ranging from 10 days to a few hours, at temperatures from 1400 to 1550C. The Th distributions in the monazite were profiled by Rutherford Backscattering Spectrometry (RBS). The following Arrhenius relation was obtained for diffusion in monazite: DSm = 7.2x103 exp(-814 kJ mol-1/RT) m2sec-1 The diffusivity of Th was similar for monazites containing a single REE and the mixed LREE phosphates. Th diffusion was also similar for experiments run using the Th silicate and Ca-Th phosphate sources, suggesting that the substitutional mechanism for Th in monazite, i.e, Th+4 + Si+4 for REE+3 + P+5 with the ThSiO4 source, and Th+4 + Ca+2 for 2REE+3 with the CaTh(PO4)2 source, does not significantly affect Th diffusivities, and that Th is likely the rate-limiting species. Th diffusion in monazite is about 4 orders of magnitude slower than Pb diffusion (Cherniak et al., 2004). This contrasts with findings of Gardes et al. (2005) who determined that Pb, Th and REE diffusivities in monazite are similar. Th diffusion in zircon (Cherniak et al., 1997) is about an order of magnitude slower than in monazite, but with similar activation energy for diffusion. The smaller diffusivities in zircon may be a consequence of the larger disparity in size between Th and the Zr site in zircon as compared with Th and the REE site in monazite. Nonetheless, Th is essentially immobile in monazite with respect to exchange by volume diffusion under most geologic conditions; these findings may have implications for containment of high- level actinide

  7. Thorium in occupationally exposed men.

    SciTech Connect

    Stehney, A. F.

    1999-02-24

    Higher than environmental levels of {sup 232}Th have been found in autopsy samples of lungs and other organs from four former employees of a thorium refinery. Working periods of the subjects ranged from 3 to 24 years, and times from end of work to death ranged from 6 to 31 years. Examination of the distribution of thorium among the organs revealed poor agreement with the distribution calculated from the dosimetric models in Publication 30 of the International Commission on Radioprotection (ICRP). Concentrations in the lungs relative to pulmonary lymph nodes, bone or liver were much higher than calculated from the model for class Y thorium and the exposure histories of the workers. Much better agreement was found with more recently proposed models in Publications 68 and 69 of the ICRP. Radiation doses estimated from the amounts of thorium in the autopsy samples were compatible with health studies that found no significant difference in mortality from that of the general population of men in the US.

  8. Thorium: Issues and prospects in Malaysia

    NASA Astrophysics Data System (ADS)

    AL-Areqi, Wadeeah M.; Majid, Amran Ab.; Sarmani, Sukiman; Bahri, Che Nor Aniza Che Zainul

    2015-04-01

    In Malaysia, thorium exists in minerals and rare earth elements production residue. The average range of thorium content in Malaysian monazite and xenotime minerals was found about 70,000 and 15,000 ppm respectively. About 2,636 tonnes of Malaysian monazite was produced for a period of 5 years (2006-2010) and based on the above data, it can be estimated that Malaysian monazite contains about 184.5 tonnes of thorium. Although thorium can become a major radiological problem to our environment, but with the significant deposit of thorium in Malaysian monazite, it has a prospect as a future alternative fuel in nuclear technology. This paper will discuss the thorium issues in Malaysia especially its long term radiological risks to public health and environment at storage and disposal stages, the prospect of exploring and producing high purity thorium from our rare earth elements minerals for future thorium based reactor. This paper also highlights the holistic approach in thorium recovery from Malaysian rare earth element production residue to reduce its radioactivity and extraction of thorium and rare earth elements from the minerals with minimum radiological impact to health and environment.

  9. Thorium: Issues and prospects in Malaysia

    SciTech Connect

    AL-Areqi, Wadeeah M.; Majid, Amran Ab.; Sarmani, Sukiman; Bahri, Che Nor Aniza Che Zainul

    2015-04-29

    In Malaysia, thorium exists in minerals and rare earth elements production residue. The average range of thorium content in Malaysian monazite and xenotime minerals was found about 70,000 and 15,000 ppm respectively. About 2,636 tonnes of Malaysian monazite was produced for a period of 5 years (2006-2010) and based on the above data, it can be estimated that Malaysian monazite contains about 184.5 tonnes of thorium. Although thorium can become a major radiological problem to our environment, but with the significant deposit of thorium in Malaysian monazite, it has a prospect as a future alternative fuel in nuclear technology. This paper will discuss the thorium issues in Malaysia especially its long term radiological risks to public health and environment at storage and disposal stages, the prospect of exploring and producing high purity thorium from our rare earth elements minerals for future thorium based reactor. This paper also highlights the holistic approach in thorium recovery from Malaysian rare earth element production residue to reduce its radioactivity and extraction of thorium and rare earth elements from the minerals with minimum radiological impact to health and environment.

  10. A fluorimetric study of the thorium-morin system

    USGS Publications Warehouse

    Milkey, R.G.; Fletcher, M.H.

    1957-01-01

    Thorium reacts with morin to yield a yellow complex that fluoresces when irradiated with ultraviolet light. The effect on the fluorescence of such variables as concentration of acid, alcohol, thorium, morin, and complex; time, temperature and wave length of exciting light are studied to determine experimental conditions yielding maximum fluorescence. The effects of Zr+4, Al+3, Fe+3, Ca+2 and La+3 are discussed. The fundamental relationships between light absorption and fluorescence are expressed in a general equation that applies to a three-component system when the fluorescence is measured in a transmission-type fluorimeter. This general equation is used to obtain an expression for the fluorescence of the thoriummorin system. Equations, derived from experimental data, relate both the fraction of thorium reacted to form complex and the fraction of unquenched fluorescence to the concentration of uncombined morin. These functions, when combined with the general equation, give an expression whichrelates the total net fluorescence to the amount of uncombined morin in the solution. This last equation can be used to determine the one region for the concentration of uncombined morin that gives maximum sensitivity for the system. Calculated standard curves are in good agreement with experimental curves.

  11. Thorium: Determination by CDTN, Brazil

    NASA Astrophysics Data System (ADS)

    Menezes, M. A. B. C.; Sabino, C. V. S.

    1999-01-01

    One of the tasks of the Radiochemical Sector, CDTN/CNEN, Brazil, is to meet the clients' analytical needs. The Sector has been facing the challenges of determining several elements in diversified matrixes from all over the country since the sixties. It has been giving analytical support to universities, industries, environmental monitoring programs, research institutes. Due to the growing need to determine thorium isotopes through the years it was necessary to work out a routine procedures. Nowadays the determination of thorium consists of a well established routine whose procedures are applied to grouped samples according to their kind, physical state, matrix interference, detection limits and number of samples. This paper describes the methods used by CDTN to determine232Th by neutron activation analysis and230Th and228Th by radiochemical separations and alpha spectrometry in several matrixes.

  12. Electrostatic Radionuclide Separation: A New Version of Rutherford's "Thorium Cow".

    ERIC Educational Resources Information Center

    Eiswirth, Marcus; And Others

    1982-01-01

    Describes three experiments (also useful as demonstrations) using a "thorium cow," a device which concentrates the daughter products from thorium compounds by precipitation on a charged electrode. (JN)

  13. Electrostatic Radionuclide Separation: A New Version of Rutherford's "Thorium Cow".

    ERIC Educational Resources Information Center

    Eiswirth, Marcus; And Others

    1982-01-01

    Describes three experiments (also useful as demonstrations) using a "thorium cow," a device which concentrates the daughter products from thorium compounds by precipitation on a charged electrode. (JN)

  14. FAST NEUTRON DOSIMETER FOR HIGH TEMPERATURE OPERATION BY MEASUREMENT OF THE AMOUNT OF CESIUM 137 FORMED FROM A THORIUM WIRE

    DOEpatents

    McCune, D.A.

    1964-03-17

    A method and device for measurement of integrated fast neutron flux in the presence of a large thermal neutron field are described. The device comprises a thorium wire surrounded by a thermal neutron attenuator that is, in turn, enclosed by heat-resistant material. The method consists of irradiating the device in a neutron field whereby neutrons with energies in excess of 1.1 Mev cause fast fissions in the thorium, then removing the thorium wire, separating the cesium-137 fission product by chemical means from the thorium, and finally counting the radioactivity of the cesium to determine the number of fissions which have occurred so that the integrated fast flux may be obtained. (AEC)

  15. SOLID STATE BONDING OF THORIUM WITH ALUMINUM

    DOEpatents

    Storchhelm, S.

    1959-12-01

    A method is described for bonding thorium and aluminum by placing clean surfaces of thorium and aluminum in contact with each other and hot pressing the metals together in a protective atmosphere at a temperature of about 375 to 575 deg C and at a pressure of at least 10 tsi to effect a bond.

  16. Thorium impact on tobacco root transcriptome.

    PubMed

    Mazari, Kateřina; Landa, Přemysl; Přerostová, Sylva; Müller, Karel; Vaňková, Radomíra; Soudek, Petr; Vaněk, Tomáš

    2017-03-05

    Thorium is natural actinide metal with potential use in nuclear energetics. Contamination by thorium, originated from mining activities or spills, represents environmental risk due to its radioactivity and chemical toxicity. A promising approach for cleaning of contaminated areas is phytoremediation, which need to be based, however, on detail understanding of the thorium effects on plants. In this study we investigated transcriptomic response of tobacco roots exposed to 200μM thorium for one week. Thorium application resulted in up-regulation of 152 and down-regulation of 100 genes (p-value <0.01, fold change ≥2). The stimulated genes were involved in components of jasmonic acid and salicylic acid signaling pathways and various abiotic (e.g. oxidative stress) and biotic stress (e.g. pathogens, wounding) responsive genes. Further, up-regulation of phosphate starvation genes and down-regulation of genes involved in phytic acid biosynthesis indicated that thorium disturbed phosphate uptake or signaling. Also expression of iron responsive genes was influenced. Negative regulation of several aquaporins indicated disturbance of water homeostasis. Genes potentially involved in thorium transport could be zinc-induced facilitator ZIF2, plant cadmium resistance PCR2, and ABC transporter ABCG40. This study provides the first insight at the processes in plants exposed to thorium.

  17. Preparation of thorium magnesium-zinc reduction

    NASA Technical Reports Server (NTRS)

    Hariharan, A. V.; Knighton, J. B.; Steunenberg, R. K.

    1969-01-01

    Magnesium-zinc reduction of thorium dioxide is used for the preparation of thorium metal. Potential economic advantages of this technique include use of relatively inexpensive reagents for the metal and flux phases, and production of metal of acceptable quality in good yield.

  18. Biosorption of radioactive thorium by Sargassum filipendula.

    PubMed

    Picardo, Marta Cristina; de Melo Ferreira, Ana Cristina; Augusto da Costa, Antonio Carlos

    2006-09-01

    In the present work, the biosorption of radioactive thorium was investigated using a dry biomass of Sargassum filipendula as the biosorbent material. Radioactive solutions containing between 2.0 and 500.0 microg thorium were tested by biosorption with S. filipendula, yielding uptake capacities from 20 to 100%, depending on the concentration of the solution. Kinetic studies indicated that equilibrium between the thorium solution and the solid fraction was achieved after three hours of contact and that a second-order model could express the equilibrium kinetics. In order to investigate the maximum biosorption capacity of the biomass an isotherm was done, based on the experimental data, which revealed the maximum uptake capacity to be 2.59 micromol thorium/g biomass. The experimental data fitted well to a Langmuir model, which provided a good correlation between the experimental and predicted thorium uptake values.

  19. Thorium isotopes in autopsy samples from thorium workers

    SciTech Connect

    Stehney, A.F.; Lucas, H.F.

    2000-01-01

    Concentrations of {sup 232}Th and activity ratios of {sup 228}Th to {sup 232}Th and {sup 230}Th to {sup 232}Th were determined in autopsy samples from five former employees of a thorium refinery. The ranges of {sup 232}Th activity concentrations (mBq per gram of wet tissue) were 0.17--94 in lungs, 3.9--1,210 in pulmonary lymph nodes, 0.14--1.19 in bones, 0.015--0.68 in liver, 0.97--5.8 in spleen, and 0.009--0.068 in kidneys. These concentrations are 10 to 1,000 times greater than have been reported for persons not occupationally exposed to thorium. In most of the samples, the ratios of {sup 228}Th to {sup 232}Th and {sup 232}Th to {sup 232}Th activity at death of the subject were 0.2--0.4 and 0.1--0.2, respectively. {sup 228}Th to {sup 228}Ra activity ratios ({+-} standard errors) of 0.86 {+-} 0.11 in lungs and 1.18 {+-} 0.13 in lymph nodes of one subject were obtained by calculation from ratios of {sup 228}Th to {sup 232}Th.

  20. Antineutrino monitoring of thorium reactors

    NASA Astrophysics Data System (ADS)

    Akindele, Oluwatomi A.; Bernstein, Adam; Norman, Eric B.

    2016-09-01

    Various groups have demonstrated that antineutrino monitoring can be successful in assessing the plutonium content in water-cooled nuclear reactors for nonproliferation applications. New reactor designs and concepts incorporate nontraditional fuel types and chemistry. Understanding how these properties affect the antineutrino emission from a reactor can extend the applicability of antineutrino monitoring. Thorium molten salt reactors breed 233U, that if diverted constitute a direct use material as defined by the International Atomic Energy Agency (IAEA). The antineutrino spectrum from the fission of 233U has been estimated for the first time, and the feasibility of detecting the diversion of 8 kg of 233U, within a 30 day timeliness goal has been evaluated. The antineutrino emission from a thorium reactor operating under normal conditions is compared to a diversion scenario by evaluating the daily antineutrino count rate and the energy spectrum of the detected antineutrinos at a 25 m standoff. It was found that the diversion of a significant quantity of 233U could not be detected within the current IAEA timeliness detection goal using either tests. A rate-time based analysis exceeded the timeliness goal by 23 days, while a spectral based analysis exceeds this goal by 31 days.

  1. Antineutrino monitoring of thorium reactors

    SciTech Connect

    Akindele, Oluwatomi A.; Bernstein, Adam; Norman, Eric B.

    2016-09-30

    Various groups have demonstrated that antineutrino monitoring can be successful in assessing the plutonium content in water-cooled nuclear reactors for nonproliferation applications. New reactor designs and concepts incorporate nontraditional fuel types and chemistry. Understanding how these properties affect the antineutrino emission from a reactor can extend the applicability of antineutrino monitoring. Thorium molten salt reactors breed 233U, that if diverted constitute a direct use material as defined by the International Atomic Energy Agency (IAEA). The antineutrino spectrum from the fission of 233U has been estimated for the first time, and the feasibility of detecting the diversion of 8 kg of 233U, within a 30 day timeliness goal has been evaluated. The antineutrino emission from a thorium reactor operating under normal conditions is compared to a diversion scenario by evaluating the daily antineutrino count rate and the energy spectrum of the detected antineutrinos at a 25 m standoff. It was found that the diversion of a significant quantity of 233U could not be detected within the current IAEA timeliness detection goal using either tests. In conclusion, a rate-time based analysis exceeded the timeliness goal by 23 days, while a spectral based analysis exceeds this goal by 31 days.

  2. Antineutrino monitoring of thorium reactors

    DOE PAGES

    Akindele, Oluwatomi A.; Bernstein, Adam; Norman, Eric B.

    2016-09-30

    Various groups have demonstrated that antineutrino monitoring can be successful in assessing the plutonium content in water-cooled nuclear reactors for nonproliferation applications. New reactor designs and concepts incorporate nontraditional fuel types and chemistry. Understanding how these properties affect the antineutrino emission from a reactor can extend the applicability of antineutrino monitoring. Thorium molten salt reactors breed 233U, that if diverted constitute a direct use material as defined by the International Atomic Energy Agency (IAEA). The antineutrino spectrum from the fission of 233U has been estimated for the first time, and the feasibility of detecting the diversion of 8 kg ofmore » 233U, within a 30 day timeliness goal has been evaluated. The antineutrino emission from a thorium reactor operating under normal conditions is compared to a diversion scenario by evaluating the daily antineutrino count rate and the energy spectrum of the detected antineutrinos at a 25 m standoff. It was found that the diversion of a significant quantity of 233U could not be detected within the current IAEA timeliness detection goal using either tests. In conclusion, a rate-time based analysis exceeded the timeliness goal by 23 days, while a spectral based analysis exceeds this goal by 31 days.« less

  3. Antineutrino monitoring of thorium reactors

    SciTech Connect

    Akindele, Oluwatomi A.; Bernstein, Adam; Norman, Eric B.

    2016-09-30

    Various groups have demonstrated that antineutrino monitoring can be successful in assessing the plutonium content in water-cooled nuclear reactors for nonproliferation applications. New reactor designs and concepts incorporate nontraditional fuel types and chemistry. Understanding how these properties affect the antineutrino emission from a reactor can extend the applicability of antineutrino monitoring. Thorium molten salt reactors breed 233U, that if diverted constitute a direct use material as defined by the International Atomic Energy Agency (IAEA). The antineutrino spectrum from the fission of 233U has been estimated for the first time, and the feasibility of detecting the diversion of 8 kg of 233U, within a 30 day timeliness goal has been evaluated. The antineutrino emission from a thorium reactor operating under normal conditions is compared to a diversion scenario by evaluating the daily antineutrino count rate and the energy spectrum of the detected antineutrinos at a 25 m standoff. It was found that the diversion of a significant quantity of 233U could not be detected within the current IAEA timeliness detection goal using either tests. In conclusion, a rate-time based analysis exceeded the timeliness goal by 23 days, while a spectral based analysis exceeds this goal by 31 days.

  4. Antineutrino monitoring of thorium reactors

    SciTech Connect

    Akindele, Oluwatomi A.; Bernstein, Adam; Norman, Eric B.

    2016-09-28

    Various groups have demonstrated that antineutrino monitoring can be successful in assessing the plutonium content in water-cooled nuclear reactors for nonproliferation applications. New reactor designs and concepts incorporate nontraditional fuel types and chemistry. Understanding how these properties affect the antineutrino emission from a reactor can extend the applicability of antineutrino monitoring. Thorium molten salt reactors breed 233U, that if diverted constitute a direct use material as defined by the International Atomic Energy Agency (IAEA). The antineutrino spectrum from the fission of 233U has been estimated for the first time, and the feasibility of detecting the diversion of 8 kg of 233U, within a 30 day timeliness goal has been evaluated. The antineutrino emission from a thorium reactor operating under normal conditions is compared to a diversion scenario by evaluating the daily antineutrino count rate and the energy spectrum of the detected antineutrinos at a 25 m standoff. It was found that the diversion of a significant quantity of 233U could not be detected within the current IAEA timeliness detection goal using either tests. A rate-time based analysis exceeded the timeliness goal by 23 days, while a spectral based analysis exceeds this goal by 31 days.

  5. Antineutrino monitoring of thorium reactors

    DOE PAGES

    Akindele, Oluwatomi A.; Bernstein, Adam; Norman, Eric B.

    2016-09-28

    Various groups have demonstrated that antineutrino monitoring can be successful in assessing the plutonium content in water-cooled nuclear reactors for nonproliferation applications. New reactor designs and concepts incorporate nontraditional fuel types and chemistry. Understanding how these properties affect the antineutrino emission from a reactor can extend the applicability of antineutrino monitoring. Thorium molten salt reactors breed 233U, that if diverted constitute a direct use material as defined by the International Atomic Energy Agency (IAEA). The antineutrino spectrum from the fission of 233U has been estimated for the first time, and the feasibility of detecting the diversion of 8 kg ofmore » 233U, within a 30 day timeliness goal has been evaluated. The antineutrino emission from a thorium reactor operating under normal conditions is compared to a diversion scenario by evaluating the daily antineutrino count rate and the energy spectrum of the detected antineutrinos at a 25 m standoff. It was found that the diversion of a significant quantity of 233U could not be detected within the current IAEA timeliness detection goal using either tests. A rate-time based analysis exceeded the timeliness goal by 23 days, while a spectral based analysis exceeds this goal by 31 days.« less

  6. Thorium isotopes in human tissues

    SciTech Connect

    Stehney, A.F.; Lucas, H.F.

    1991-12-31

    Concentrations of {sup 232}Th and activity ratios of {sup 228}Th to {sup 232}Th and {sup 230}Th to {sup 232}Th were determined in autopsy samples from five former employees of a thorium refinery. The ranges of {sup 232}Th activity concentrations (mBq g{sup {minus}1}) were 0.17--94 in lungs, 3.9--1210 in pulmonary lymph nodes, 0.14--1.19 in bones, 0.015--0.68 in liver, 0.97--5.8 in spleen, and 0.009--0.068 in kidneys. These concentrations are 10 to 1000 times greater than have been reported for persons not occupationally exposed to Th. In most of the samples, the ratios of {sup 230}Th to {sup 232}Th and {sup 228}Th to {sup 232}Th activity at death of the subject were 0.1--0.2 and 0.2--0.4, respectively. Thorium-228 to {sup 228}Ra activity ratios ({plus_minus} standard errors) of 0.86 {plus_minus} 0.11 in lungs and 1.18 {plus_minus} 0.13 in lymph nodes of one subject were obtained by calculation from ratios of {sup 228}Th to {sup 232}Th.

  7. Safeguards Considerations for Thorium Fuel Cycles

    DOE PAGES

    Worrall, Louise G.; Worrall, Andrew; Flanagan, George F.; ...

    2016-04-21

    We report that by around 2025, thorium-based fuel cycles are likely to be deployed internationally. States such as China and India are pursuing research, development, and deployment pathways toward a number of commercial-scale thorium fuel cycles, and they are already building test reactors and the associated fuel cycle infrastructure. In the future, the potential exists for these emerging programs to sell, export, and deploy thorium fuel cycle technology in other states. Without technically adequate international safeguards protocols and measures in place, any future potential clandestine misuse of these fuel cycles could go undetected, compromising the deterrent value of these protocolsmore » and measures. The development of safeguards approaches for thorium-based fuel cycles is therefore a matter of some urgency. Yet, the focus of the international safeguards community remains mainly on safeguarding conventional 235U- and 239Pu-based fuel cycles while the safeguards challenges of thorium-uranium fuel cycles remain largely uninvestigated. This raises the following question: Is the International Atomic Energy Agency and international safeguards system ready for thorium fuel cycles? Furthermore, is the safeguards technology of today sufficiently mature to meet the verification challenges posed by thorium-based fuel cycles? In defining these and other related research questions, the objectives of this paper are to identify key safeguards considerations for thorium-based fuel cycles and to call for an early dialogue between the international safeguards and the nuclear fuel cycle communities to prepare for the potential safeguards challenges associated with these fuel cycles. In this paper, it is concluded that directed research and development programs are required to meet the identified safeguards challenges and to take timely action in preparation for the international deployment of thorium fuel cycles.« less

  8. Safeguards Considerations for Thorium Fuel Cycles

    SciTech Connect

    Worrall, Louise G.; Worrall, Andrew; Flanagan, George F.; Croft, Steven

    2016-04-21

    We report that by around 2025, thorium-based fuel cycles are likely to be deployed internationally. States such as China and India are pursuing research, development, and deployment pathways toward a number of commercial-scale thorium fuel cycles, and they are already building test reactors and the associated fuel cycle infrastructure. In the future, the potential exists for these emerging programs to sell, export, and deploy thorium fuel cycle technology in other states. Without technically adequate international safeguards protocols and measures in place, any future potential clandestine misuse of these fuel cycles could go undetected, compromising the deterrent value of these protocols and measures. The development of safeguards approaches for thorium-based fuel cycles is therefore a matter of some urgency. Yet, the focus of the international safeguards community remains mainly on safeguarding conventional 235U- and 239Pu-based fuel cycles while the safeguards challenges of thorium-uranium fuel cycles remain largely uninvestigated. This raises the following question: Is the International Atomic Energy Agency and international safeguards system ready for thorium fuel cycles? Furthermore, is the safeguards technology of today sufficiently mature to meet the verification challenges posed by thorium-based fuel cycles? In defining these and other related research questions, the objectives of this paper are to identify key safeguards considerations for thorium-based fuel cycles and to call for an early dialogue between the international safeguards and the nuclear fuel cycle communities to prepare for the potential safeguards challenges associated with these fuel cycles. In this paper, it is concluded that directed research and development programs are required to meet the identified safeguards challenges and to take timely action in preparation for the international deployment of thorium fuel cycles.

  9. Safeguards Considerations for Thorium Fuel Cycles

    SciTech Connect

    Worrall, Louise G.; Worrall, Andrew; Flanagan, George F.; Croft, Steven

    2016-04-21

    We report that by around 2025, thorium-based fuel cycles are likely to be deployed internationally. States such as China and India are pursuing research, development, and deployment pathways toward a number of commercial-scale thorium fuel cycles, and they are already building test reactors and the associated fuel cycle infrastructure. In the future, the potential exists for these emerging programs to sell, export, and deploy thorium fuel cycle technology in other states. Without technically adequate international safeguards protocols and measures in place, any future potential clandestine misuse of these fuel cycles could go undetected, compromising the deterrent value of these protocols and measures. The development of safeguards approaches for thorium-based fuel cycles is therefore a matter of some urgency. Yet, the focus of the international safeguards community remains mainly on safeguarding conventional 235U- and 239Pu-based fuel cycles while the safeguards challenges of thorium-uranium fuel cycles remain largely uninvestigated. This raises the following question: Is the International Atomic Energy Agency and international safeguards system ready for thorium fuel cycles? Furthermore, is the safeguards technology of today sufficiently mature to meet the verification challenges posed by thorium-based fuel cycles? In defining these and other related research questions, the objectives of this paper are to identify key safeguards considerations for thorium-based fuel cycles and to call for an early dialogue between the international safeguards and the nuclear fuel cycle communities to prepare for the potential safeguards challenges associated with these fuel cycles. In this paper, it is concluded that directed research and development programs are required to meet the identified safeguards challenges and to take timely action in preparation for the international deployment of thorium fuel cycles.

  10. Method of separating thorium from plutonium

    DOEpatents

    Clifton, D.G.; Blum, T.W.

    A method of chemically separating plutonium from thorium is claimed. Plutonium and thorium to be separated are dissolved in an aqueous feed solution, preferably as the nitrate salts. The feed solution is acidified and sodium nitrite is added to the solution to adjust the valence of the plutonium to the +4 state. A chloride salt, preferably sodium chloride, is then added to the solution to induce formation of an anionic plutonium chloride complex. The anionic plutonium chloride complex and the thorium in solution are then separated by ion exchange on a strong base anion exchange column.

  11. Development of solid thorium-232 reference materials

    NASA Astrophysics Data System (ADS)

    Engelder, P. R.; Donivan, S.; Chessmore, R. B.

    1985-05-01

    Thorium-232 reference materials with a matrix similar to soil and uranium-mill tailings are necessary for ensuring uniform standardization among measurements performed by remedial-action contractors. Some 200 pounds each of three different concentrations of Th-232 reference material were prepared by diluting a thorium ore with soil. Target values for Th-232 content were 70, 30, and 10 pCi/q. The recommended thorium-232 concentrations for the three reference materials are 71.2 + or - 2.0 pCi/g, 30.5 + or - 0.6 pCi/g, and 10.2 + or - 0.3 pCi/g.

  12. Method of separating thorium from plutonium

    DOEpatents

    Clifton, D.G.; Blum, T.W.

    1984-07-10

    A method is described for chemically separating plutonium from thorium. Plutonium and thorium to be separated are dissolved in an aqueous feed solution, preferably as the nitrate salts. The feed solution is acidified and sodium nitrite is added to the solution to adjust the valence of the plutonium to the +4 state. A chloride salt, preferably sodium chloride, is then added to the solution to induce formation of an anionic plutonium chloride complex. The anionic plutonium chloride complex and the thorium in solution are then separated by ion exchange on a strong base anion exchange column.

  13. Method of separating thorium from plutonium

    DOEpatents

    Clifton, David G.; Blum, Thomas W.

    1984-01-01

    A method of chemically separating plutonium from thorium. Plutonium and thorium to be separated are dissolved in an aqueous feed solution, preferably as the nitrate salts. The feed solution is acidified and sodium nitrite is added to the solution to adjust the valence of the plutonium to the +4 state. A chloride salt, preferably sodium chloride, is then added to the solution to induce formation of an anionic plutonium chloride complex. The anionic plutonium chloride complex and the thorium in solution are then separated by ion exchange on a strong base anion exchange column.

  14. Utilisation de l'essai comete et du biomarqueur gamma-H2AX pour detecter les dommages induits a l'ADN cellulaire par le 5-bromodeoxyuridine post-irradiation

    NASA Astrophysics Data System (ADS)

    La Madeleine, Carole

    Ce memoire est presente a la Faculte de medecine et des sciences de la sante de l'Universite de Sherbrooke en vue de l'obtention du grade de maitre es sciences (M.Sc.) en radiobiologie (2009). Un jury a revise les informations contenues dans ce memoire. Il etait compose de professeurs de la Faculte de medecine et des sciences de la sante soit : Darel Hunting PhD, directeur de recherche (departement de medecine nucleaire et radiobiologie), Leon Sanche PhD, directeur de recherche (departement de medecine nucleaire et radiobiologie), Richard Wagner PhD, membre du programme (departement de medecine nucleaire et radiobiologie) et Guylain Boissonneault PhD, membre exterieur au programme (departement de biochimie). Le 5-bromodeoxyuridine (BrdU), un analogue halogene de la thymidine reconnu depuis les annees 60 comme etant un excellent radiosensibilisateur. L'hypothese la plus repandue au sujet de l'effet radio sensibilisant du BrdU est qu'il augmente le nombre de cassures simple et double brin lorsqu'il est incorpore dans l'ADN de la cellule et expose aux radiations ionisantes. Toutefois, de nouvelles recherches semblent remettre en question les observations precedentes. Ces dernieres etudes ont confirme que le BrdU est un bon radiosensibilisateur, car il augmente les dommages radio-induits dans l'ADN. Mais, c'est en etant incorpore dans une region simple brin que le BrdU radiosensibilise l'ADN. Ces recherches ont egalement revele pour la premiere fois un nouveau type de dommages produits lors de l'irradiation de l'ADN contenant du BrdU : les dimeres interbrins. Le but de ces travaux de recherche est de determiner si la presence de bromodeoxyuridine dans l'ADN augmente l'induction de bris simple et / ou double brin chez les cellules irradiees en utilisant de nouvelles techniques plus sensibles et specifiques que celles utilisees auparavant. Pour ce faire, les essais cometes et la detection des foci H2AX phosphorylee pourraient permettre d'etablir les effets engendres par

  15. Fabrication of thorium bearing carbide fuels

    DOEpatents

    Gutierrez, Rueben L.; Herbst, Richard J.; Johnson, Karl W. R.

    1981-01-01

    Thorium-uranium carbide and thorium-plutonium carbide fuel pellets have been fabricated by the carbothermic reduction process. Temperatures of 1750.degree. C. and 2000.degree. C. were used during the reduction cycle. Sintering temperatures of 1800.degree. C. and 2000.degree. C. were used to prepare fuel pellet densities of 87% and >94% of theoretical, respectively. The process allows the fabrication of kilogram quantities of fuel with good reproducibility of chemicals and phase composition. Methods employing liquid techniques that form carbide microspheres or alloying-techniques which form alloys of thorium-uranium or thorium-plutonium suffer from limitation on the quantities processed of because of criticality concerns and lack of precise control of process conditions, respectively.

  16. Thorium: Crustal abundance, joint production, and economic availability

    DOE PAGES

    Jordan, Brett W.; Eggert, Roderick G.; Dixon, Brent W.; ...

    2015-03-02

    Recently, interest in thorium's potential use in a nuclear fuel cycle has been renewed. Thorium is more abundant, at least on average, than uranium in the earth's crust and, therefore, could theoretically extend the use of nuclear energy technology beyond the economic limits of uranium resources. This paper provides an economic assessment of thorium availability by creating cumulative-availability and potential mining-industry cost curves, based on known thorium resources. These tools provide two perspectives on the economic availability of thorium. In the long term, physical quantities of thorium likely will not be a constraint on the development of a thorium fuelmore » cycle. In the medium term, however, thorium supply may be limited by constraints associated with its production as a by-product of rare earth elements and heavy mineral sands. As a result, environmental concerns, social issues, regulation, and technology also present issues for the medium and long term supply of thorium.« less

  17. Thorium: Crustal abundance, joint production, and economic availability

    SciTech Connect

    Jordan, Brett W.; Eggert, Roderick G.; Dixon, Brent W.; Carlsen, Brett W.

    2015-03-02

    Recently, interest in thorium's potential use in a nuclear fuel cycle has been renewed. Thorium is more abundant, at least on average, than uranium in the earth's crust and, therefore, could theoretically extend the use of nuclear energy technology beyond the economic limits of uranium resources. This paper provides an economic assessment of thorium availability by creating cumulative-availability and potential mining-industry cost curves, based on known thorium resources. These tools provide two perspectives on the economic availability of thorium. In the long term, physical quantities of thorium likely will not be a constraint on the development of a thorium fuel cycle. In the medium term, however, thorium supply may be limited by constraints associated with its production as a by-product of rare earth elements and heavy mineral sands. As a result, environmental concerns, social issues, regulation, and technology also present issues for the medium and long term supply of thorium.

  18. Fabrication of thorium bearing carbide fuels

    DOEpatents

    Gutierrez, R.L.; Herbst, R.J.; Johnson, K.W.R.

    Thorium-uranium carbide and thorium-plutonium carbide fuel pellets have been fabricated by the carbothermic reduction process. Temperatures of 1750/sup 0/C and 2000/sup 0/C were used during the reduction cycle. Sintering temperatures of 1800/sup 0/C and 2000/sup 0/C were used to prepare fuel pellet densities of 87% and > 94% of theoretical, respectively. The process allows the fabrication of kilogram quantities of fuel with good reproductibility of chemical and phase composition.

  19. Radiotoxicity Characterization of Multi-Recycled Thorium Fuel - 12394

    SciTech Connect

    Franceschini, F.; Wenner, M.; Fiorina, C.; Huang, M.; Petrovic, B.; Krepel, J.

    2012-07-01

    As described in companion papers, Westinghouse is proposing the implementation of a thorium based fuel cycle to burn the transuranic (TRU) contained in the used nuclear fuel. The potential of thorium as a TRU burner is described in another paper presented at this conference. This paper analyzes the long-term impact of thorium on the front-end and backend of the fuel cycle. This is accomplished by an assessment of the isotopic make-up of Th in a closed cycle and its impact on representative metrics, such as radiotoxicity, decay heat and gamma heat. The behavior in both thermal and fast neutron energy ranges has been investigated. Irradiation in a Th fuel PWR has been assumed as representative of the thermal range, while a Th fuel fast reactor (FR) has been employed to characterize the behavior in the high-energy range. A comparison with a U-fuel closed-cycle FR has been undertaken in an attempt of a more comprehensive evaluation of each cycle's long-term potential. As the Th fuel undergoes multiple cycles of irradiation, the isotopic composition of the recycled fuel changes. Minor Th isotopes are produced; U-232 and Pa-231 build up; the U vector gradually shifts towards increasing amounts of U-234, U-235 etc., eventually leading to the production of non negligible amounts of TRU isotopes, especially Pu-238. The impact of the recycled fuel isotopic makeup on the in-core behavior is mild, and for some aspects beneficial, i.e. the reactivity swing during irradiation is reduced as the fertile characteristics of the fuel increase. On the other hand, the front and the back-end of the fuel cycle are negatively affected due to the presence of Th-228 and U-232 and the build-up of higher actinides (Pu-238 etc.). The presence of U-232 can also be seen as advantageous as it represents an obstacle to potential proliferators. Notwithstanding the increase in the short-term radiotoxicity and decay heat in the multi-recycled fuel, the Th closed cycle has some potentially substantial

  20. TRISO Fuel Performance: Modeling, Integration into Mainstream Design Studies, and Application to a Thorium-fueled Fusion-Fission Hybrid Blanket

    SciTech Connect

    Powers, Jeffrey James

    2011-11-30

    This study focused on creating a new tristructural isotropic (TRISO) coated particle fuel performance model and demonstrating the integration of this model into an existing system of neutronics and heat transfer codes, creating a user-friendly option for including fuel performance analysis within system design optimization and system-level trade-off studies. The end product enables both a deeper understanding and better overall system performance of nuclear energy systems limited or greatly impacted by TRISO fuel performance. A thorium-fueled hybrid fusion-fission Laser Inertial Fusion Energy (LIFE) blanket design was used for illustrating the application of this new capability and demonstrated both the importance of integrating fuel performance calculations into mainstream design studies and the impact that this new integrated analysis had on system-level design decisions. A new TRISO fuel performance model named TRIUNE was developed and verified and validated during this work with a novel methodology established for simulating the actual lifetime of a TRISO particle during repeated passes through a pebble bed. In addition, integrated self-consistent calculations were performed for neutronics depletion analysis, heat transfer calculations, and then fuel performance modeling for a full parametric study that encompassed over 80 different design options that went through all three phases of analysis. Lastly, side studies were performed that included a comparison of thorium and depleted uranium (DU) LIFE blankets as well as some uncertainty quantification work to help guide future experimental work by assessing what material properties in TRISO fuel performance modeling are most in need of improvement. A recommended thorium-fueled hybrid LIFE engine design was identified with an initial fuel load of 20MT of thorium, 15% TRISO packing within the graphite fuel pebbles, and a 20cm neutron multiplier layer with beryllium pebbles in flibe molten salt coolant. It operated

  1. A novel concept of QUADRISO particles Part III : applications to the plutonium-thorium fuel cycle.

    SciTech Connect

    Talamo, A.

    2009-03-01

    In the present study, a plutonium-thorium fuel cycle is investigated including the {sup 233}U production and utilization. A prismatic thermal High Temperature Gas Reactor (HTGR) and the novel concept of quadruple isotropic (QUADRISO) coated particles, designed at the Argonne National Laboratory, have been used for the study. In absorbing QUADRISO particles, a burnable poison layer surrounds the central fuel kernel to flatten the reactivity curve as a function of time. At the beginning of life, the fuel in the QUADRISO particles is hidden from neutrons, since they get absorbed in the burnable poison before they reach the fuel kernel. Only when the burnable poison depletes, neutrons start streaming into the fuel kernel inducing fission reactions and compensating the fuel depletion of ordinary TRISO particles. In fertile QUADRISO particles, the absorber layer is replaced by natural thorium with the purpose of flattening the excess of reactivity by the thorium resonances and producing {sup 233}U. The above configuration has been compared with a configuration where fissile (neptunium-plutonium oxide from Light Water Reactors irradiated fuel) and fertile (natural thorium oxide) fuels are homogeneously mixed in the kernel of ordinary TRISO particles. For the {sup 233}U utilization, the core has been equipped with europium oxide absorbing QUADRISO particles.

  2. Composition of hydroponic medium affects thorium uptake by tobacco plants.

    PubMed

    Soudek, Petr; Kufner, Daniel; Petrová, Sárka; Mihaljevič, Martin; Vaněk, Tomáš

    2013-08-01

    The ability of thorium uptake as well as responses to heavy metal stress were tested in tobacco cultivar La Burley 21. Thorium was accumulated preferentially in the root system. The presence of citric, tartaric and oxalic acids in hydroponic medium increased thorium accumulation in all plant organs. On the other hand, the addition of diamines and polyamines, the important antioxidants in plants, resulted in decrease of thorium accumulation, especially in the root system. Negative correlation was found between putrescine concentration and thorium accumulation. Nevertheless, the most important factor influencing the accumulation of thorium was the absence of phosphate ions in a hydroponic medium that caused more than 10-fold increase of thorium uptake in all plant parts. Accumulation and distribution of thorium was followed in six cultivars and 14 selected transformants. Cultivar La Barley 21 represented an average between the tested genotypes, having a very good distribution ratio between roots, stems and leaves.

  3. Radionécrose cérébrale chez des patients irradiés pour cancers du nasopharynx: à propos de 3 cas

    PubMed Central

    El Mazghi, Abderrahman; Lalya, Issam; Loukili, Kaoutar; El Kacemi, Hanan; Kebdani, Taieb; Hassouni, Khalid

    2014-01-01

    La radionécrose cérébrale est une complication tardive, iatrogène, relativement rare de la radiothérapie qui survient après plus de six mois suivant le début du traitement. Elle pourrait s'expliquer par la conjonction de lésions vasculaires, gliales et d'ordre immunologiques. Elle peut mettre en jeu le pronostic fonctionnel et vital du malade. La prévention de cette affection redoutable est fondamentale vu l'absence de traitement potentiellement efficace. Nous rapportons 03 nouveaux cas, chez des patients traités par chimiothérapie d'induction puis radio- chimiothérapie concomitante pour des cancers localement avancés du nasopharynx. Le diagnostic a été orienté par l'IRM spectroscopique et l’évolution était favorable sous corticothérapie dans les 03 cas. PMID:25722784

  4. Potential synergy: the thorium fuel cycle and rare earths processing

    SciTech Connect

    Ault, T.; Wymer, R.; Croff, A.; Krahn, S.

    2013-07-01

    The use of thorium in nuclear power programs has been evaluated on a recurring basis. A concern often raised is the lack of 'thorium infrastructure'; however, for at least a part of a potential thorium fuel cycle, this may less of a problem than previously thought. Thorium is frequently encountered in association with rare earth elements and, since the U.S. last systematically evaluated the large-scale use of thorium (the 1970's,) the use of rare earth elements has increased ten-fold to approximately 200,000 metric tons per year. Integration of thorium extraction with rare earth processing has been previously described and top-level estimates have been done on thorium resource availability; however, since ores and mining operations differ markedly, what is needed is process flowsheet analysis to determine whether a specific mining operation can feasibly produce thorium as a by-product. Also, the collocation of thorium with rare earths means that, even if a thorium product stream is not developed, its presence in mining waste streams needs to be addressed and there are previous instances where this has caused issues. This study analyzes several operational mines, estimates the mines' ability to produce a thorium by-product stream, and discusses some waste management implications of recovering thorium. (authors)

  5. THORIUM-BERYLLIUM ALLOYS AND METHOD OF PRODUCING SAME

    DOEpatents

    Spedding, F.H.; Wilhelm, H.A.; Keller, W.H.

    1959-09-01

    >The preparation is described of thorium-berylium alloys from halides of the metals by stmultaneously reducing thorium fluoride and beryllium fluoride with calcium at approximately 650 deg C and maintaining the temperature until the thorium-beryhltum alloy separates from the slag.

  6. Removal of thorium from Eneabba North Ilmenite

    SciTech Connect

    Aral, H.; Bruckard, W.J.; Freeman, D.E.

    1996-12-31

    Physical and chemical methods were investigated to lower thorium, levels in Eneabba ilmenite from the natural levels of 180-500 ppm to give Becher Process synthetic ruffle with less than 100 ppm thorium. Chemical treatments, but not physical separations were successful. A pilot plant trial of a sodium hydroxide leach (2.5M NaOH at 75{degrees}C and 40 wt% solids for 1h) followed by a sulphuric acid leach (3M H{sub 2}SO{sub 4} at 90{degrees}C and 60 wt% solids for 2h) confirmed that thorium could be removed to below 100 ppm. However, the activity of the ilmenite was not lowered to the same extent. 5 refs., 1 fig., 12 tabs.

  7. Thorium removal by different adsorbents.

    PubMed

    Metaxas, Michail; Kasselouri-Rigopoulou, Vasilia; Galiatsatou, Polymnia; Konstantopoulou, Cathrine; Oikonomou, Dimitrios

    2003-02-28

    The removal of radiotoxic Th(4+) from aqueous solutions has been explored using two different groups of adsorptive materials (e.g. two activated carbons and four zeolites-two natural and two synthetic). The activated carbons were prepared from solvent extracted olive pulp (SEOP) and olive stone (OS) by a two-step physical activation method with steam. They were characterized by N(2) at 77K adsorption, Hg porosimetry and by determination of their iodine number. All carbons prepared are of the H-type (e.g. contain mainly basic surface oxides) confirmed by the results of the Boehm's method. The natural zeolites, clinoptilolite (NaCLI) and mordenite (NaMOR), were pretreated with Na(+) before the adsorption experiments, while the synthetic ones, NaX and NaA, were provided in their commercial sodium form. The natural zeolites, NaCLI and NaMOR, utilized 11.5 and 38.6% of the theoretical ion-exchange capacity, based on Al content, respectively, while NaX and NaA utilized 41.5 and 45.9%, respectively. The activated carbons showed better removal capability than NaCLI. NaMOR, showed comparable results to the carbon originated from OS, but lower removal capability than the carbon originated from SEOP. The synthetic zeolites showed the highest removal ability for thorium ions due to their increased ion-exchange capacity because of their cleaner and larger framework channels and their higher number of ion-exchange sites. The carbons adsorption capacity mainly depends on the content and nature of functional surface groups. The adsorption data were fitted to Langmuir and Freundlich models. The former achieved best fits and was further applied to obtain the respective Langmuir constant and maximum adsorption capacity for each system.

  8. SEPARATION OF THORIUM FROM URANIUM BY EXTRACTION

    DOEpatents

    Bohlmann, E.G.

    1959-07-28

    A method is presented for the recovery and separation of uranium and thorium values contained in an aqueous nitric acid solution which is more than 3 M in nitric acid. The uranium and thorium containing solution preferable about 7 M in nitric acid is contacted with tributyl phosphatekerosene mixture. Both U and Th are extracted by the immiscible organic. After phase separation the Th is selectively back extracted by contacting with an aqueous nitric acid solution preferably between 0.1 to 1.5 M in nitric acid. The uranium which is still in the organic extractant phase may be recovered by contacting with water.

  9. Plutonium transmutation in thorium fuel cycle

    SciTech Connect

    Necas, Vladimir; Breza, Juraj |; Darilek, Petr

    2007-07-01

    The HELIOS spectral code was used to study the application of the thorium fuel cycle with plutonium as a supporting fissile material in a once-through scenario of the light water reactors PWR and VVER-440 (Russian design). Our analysis was focused on the plutonium transmutation potential and the plutonium radiotoxicity course of hypothetical thorium-based cycles for current nuclear power reactors. The paper shows a possibility to transmute about 50% of plutonium in analysed reactors. Positive influence on radiotoxicity after 300 years and later was pointed out. (authors)

  10. PREPARATION OF HIGH-DENSITY, COMPACTIBLE THORIUM OXIDE PARTICLES

    DOEpatents

    McCorkle, K.H.; Kleinsteuber, A.T.; Schilling, C.E.; Dean, O.C.

    1962-05-22

    A method is given for preparing millimeter-size, highdensity thorium oxide particles suitable for fabrication into nuclear reactor feel elements by means of vibratory compaction. A thorium oxide gel containing 3.7 to 7 weight per cent residual volatile nitrate and water is prepared by drying a thorium oxide sol. The gel is then slowly heated to a temperature of about 450DEC, and the resulting gel fragments are calcined. The starting sol is prepared by repeated dispersion of oxalate-source thorium oxide in a nitrate system or by dispersion of steam-denitrated thorium oxide in water. (AEC)

  11. Reactor production of Thorium-229

    DOE PAGES

    Boll, Rose Ann; Murphy, Karen E.; Denton, David L.; ...

    2016-05-03

    Limited availability of 229Th for clinical applications of 213Bi necessitates investigation of alternative production routes. In reactor production, 229Th is produced from neutron transmutation of 226Ra, 228Ra, 227Ac and 228Th. Here, we evaluate irradiations of 226Ra, 228Ra, and 227Ac targets at the ORNL High Flux Isotope Reactor.

  12. Natural thorium resources and recovery: Options and impacts

    USGS Publications Warehouse

    Ault, Timothy; Van Gosen, Bradley S.; Krahn, Steven; Croff, Allen

    2016-01-01

    This paper reviews the front end of the thorium fuel cycle, including the extent and variety of thorium deposits, the potential sources of thorium production, and the physical and chemical technologies required to isolate and purify thorium. Thorium is frequently found within rare earth element–bearing minerals that exist in diverse types of mineral deposits, often in conjunction with other minerals mined for their commercial value. It may be possible to recover substantial quantities of thorium as a by-product from active titanium, uranium, tin, iron, and rare earth mines. Incremental physical and chemical processing is required to obtain a purified thorium product from thorium minerals, but documented experience with these processes is extensive, and incorporating thorium recovery should not be overly challenging. The anticipated environmental impacts of by-product thorium recovery are small relative to those of uranium recovery since existing mining infrastructure utilization avoids the opening and operation of new mines and thorium recovery removes radionuclides from the mining tailings.

  13. Design and Analysis of Thorium-fueled Reduced Moderation Boiling Water Reactors

    NASA Astrophysics Data System (ADS)

    Gorman, Phillip Michael

    The Resource-renewable Boiling Water Reactors (RBWRs) are a set of light water reactors (LWRs) proposed by Hitachi which use a triangular lattice and high void fraction to incinerate fuel with an epithermal spectrum, which is highly atypical of LWRs. The RBWRs operate on a closed fuel cycle, which is impossible with a typical thermal spectrum reactor, in order to accomplish missions normally reserved for sodium fast reactors (SFRs)--either fuel self-sufficiency or waste incineration. The RBWRs also axially segregate the fuel into alternating fissile "seed" regions and fertile "blanket" regions in order to enhance breeding and leakage probability upon coolant voiding. This dissertation focuses on thorium design variants of the RBWR: the self-sufficient RBWR-SS and the RBWR-TR, which consumes reprocessed transuranic (TRU) waste from PWR used nuclear fuel. These designs were based off of the Hitachi-designed RBWR-AC and the RBWR-TB2, respectively, which use depleted uranium (DU) as the primary fertile fuel. The DU-fueled RBWRs use a pair of axially segregated seed sections in order to achieve a negative void coefficient; however, several concerns were raised with this multi-seed approach, including difficulty with controlling the reactor and unacceptably high axial power peaking. Since thorium-uranium fuel tends to have much more negative void feedback than uranium-plutonium fuels, the thorium RBWRs were designed to use a single elongated seed to avoid these issues. A series of parametric studies were performed in order to find the design space for the thorium RBWRs, and optimize the designs while meeting the required safety constraints. The RBWR-SS was optimized to maximize the discharge burnup, while the RBWR-TR was optimized to maximize the TRU transmutation rate. These parametric studies were performed on an assembly level model using the MocDown simulator, which calculates an equilibrium fuel composition with a specified reprocessing scheme. A full core model was

  14. Minor actinide transmutation in thorium and uranium matrices in heavy water moderated reactors

    SciTech Connect

    Bhatti, Zaki; Hyland, B.; Edwards, G.W.R.

    2013-07-01

    The irradiation of Th{sup 232} breeds fewer of the problematic minor actinides (Np, Am, Cm) than the irradiation of U{sup 238}. This characteristic makes thorium an attractive potential matrix for the transmutation of these minor actinides, as these species can be transmuted without the creation of new actinides as is the case with a uranium fuel matrix. Minor actinides are the main contributors to long term decay heat and radiotoxicity of spent fuel, so reducing their concentration can greatly increase the capacity of a long term deep geological repository. Mixing minor actinides with thorium, three times more common in the Earth's crust than natural uranium, has the additional advantage of improving the sustainability of the fuel cycle. In this work, lattice cell calculations have been performed to determine the results of transmuting minor actinides from light water reactor spent fuel in a thorium matrix. 15-year-cooled group-extracted transuranic elements (Np, Pu, Am, Cm) from light water reactor (LWR) spent fuel were used as the fissile component in a thorium-based fuel in a heavy water moderated reactor (HWR). The minor actinide (MA) transmutation rates, spent fuel activity, decay heat and radiotoxicity, are compared with those obtained when the MA were mixed instead with natural uranium and taken to the same burnup. Each bundle contained a central pin containing a burnable neutron absorber whose initial concentration was adjusted to have the same reactivity response (in units of the delayed neutron fraction β) for coolant voiding as standard NU fuel. (authors)

  15. PRODUCTION OF URANIUM AND THORIUM COMPOUNDS

    DOEpatents

    Arden, T.V.; Burstall, F.H.; Linstead, R.P.; Wells, R.A.

    1955-12-27

    Compounds of Th and U are extracted with an organic solvent in the presence of an adsorbent substance which has greater retentivity for impurities present than for the uranium and/or thorium. The preferred adsorbent material is noted as being cellulose. The uranium and thoriumcontaining substances treated are preferably in the form of dissolved nitrates, and the preferred organic solvent is diethyl ether.

  16. Standard reference materials for thorium analysis.

    PubMed

    Holmes, L

    2001-01-01

    Reference materials (RMs) are used in analytical measurements for several purposes--to develop and validate analytical measurements, as quality control indicators and for calibration. It is therefore essential that suitable reference materials are available. Because thorium is usually found in very acid-resistant, mineral phases, this becomes even more critical when techniques such as ICP-MS are used, which require complete sample digestion. This paper gives an overview of the reference materials that are currently available for thorium (232Th and other thorium isotopes) in various matrices, sources and indicative costs. The IAEA database is identified as a particularly useful source of information, and the website address is: http://www.iaea.org/programmes/nahunet/e4/nmrm/index.htm A brief summary of the discussion held at the '1st European Workshop on the Analysis of Thorium in Workplace Materials', regarding reference materials, is given at the end of the paper. A general need for new RMs, specifically for workplace materials, was identified as a priority.

  17. Practical introduction of thorium fuel cycles

    SciTech Connect

    Kasten, P.R.

    1982-01-01

    The pracitcal introduction of throrium fuel cycles implies that thorium fuel cycles compete economically with uranium fuel cycles in economic nuclear power plants. In this study the reactor types under consideration are light water reactors (LWRs), heavy water reactors (HWRs), high-temperature gas-cooled reactors (HTGRs), and fast breeder reactors (FBRs). On the basis that once-through fuel cycles will be used almost exclusively for the next 20 or 25 years, introduction of economic thorium fuel cycles appears best accomplished by commercial introduction of HTGRs. As the price of natural uranium increases, along with commercialization of fuel recycle, there will be increasing incentive to utilize thorium fuel cycles in heavy water reactors and light water reactors as well as in HTGRs. After FBRs and fuel recycle are commercialized, use of thorium fuel cycles in the blanket of FBRs appears advantageous when fast breeder reactors and thermal reactors operate in a symbiosis mode (i.e., where /sup 233/U bred in the blanket of a fast breeder reactor is utilized as fissile fuel in thermal converter reactors).

  18. Thorium mobilization in a terrestrial environment

    SciTech Connect

    Lei, W.

    1984-01-01

    The mobilization of naturally-occurring thorium from an ore body containing about 30,000 metric tons has been used to assess the potential for tetravalent plutonium transport from a deep geologic waste repository that has been eroded to the surface of the earth and breached by groundwater. Thorium mobility from the deposit was assessed due to water erosion and groundwater solubilization. The ore body is estimated to be about 60 million years old and is located, in an exposed and highly weathered condition, near the summit of a hill in the State of Minas Gerais, Brazil. Rainfall during the one year period of study (177 cm) was close to the 30 year mean of 170 cm. Most of the precipitation occurs during a four month rainy season. It was found that storm runoff yields a fractional removal rate of 10/sup -6/ yr/sup -1/ mainly by surface erosion while groundwater solubilization resulted in a removal rate of 10/sup -9/ yr/sup -1/. Thus, physical transport in surface runofff dominates by three orders of magnitude and is the primary mechanism for thorium removal from the ore body under current environmental conditions. The mean life of the thorium in the deposit is 10/sup 6/ years if controlled by rainfall erosion and 10/sup 9/ years if controlled by groundwater solubilization, respectively. Because of the improbability that a deep geologic repository will become exposed at the surface of the earth, groundwater solubilization is a more relevant mobilization mechanism than erosion.

  19. X-ray powder data for uranium and thorium minerals

    USGS Publications Warehouse

    Frondel, Clifford; Riska, Daphne; Frondel, Judith Weiss

    1956-01-01

    The U.S. Geological Survey has in preparation a comprehensive volume on the mineralogy of uranium and thorium. This work has been done as part of a continuing systematic survey of data on uranium and thorium minerals on behalf of the Division of Raw Materials, U.S. Atomic Energy Commission. Pending publication of this volume and in response to a widespread demand among workers in uranium and thorium mineralogy, the X-ray powder diffraction data for the known minerals that contain uranium or thorium as an essential constituent are presented here. The coverage is complete except for a few minerals for which there are no reliable data owing to lack of authentic specimens. With the exception of that for ianthinite, the new data either originated in the Geological Survey or in the Mineralogical Laboratory of Harvard University. Data from the literature or other sources were cross-checked against the files of standard patterns of these laboratories; the sources are indicated in the references. Data not accompanied by a reference were obtained from films in the Harvard Standard File and cross-checked as to the identity of the film with the Geological Survey's file. Minor differences can be expected in the d-spacings reported for the same specimens by different investigators because of the manner of preparation of the mount, the conditions of X-ray irradiation, and the method of photography and measurement of the film or chart. The Harvard and Geological Survey data all were obtained from films taken in 114-mm diameter cameras, using either ethyl cellulose and toluene or collodion spindle mounts and Straumanis-type film mounting. Unless otherwise indicated all patterns were taken with copper radiation (Kα 1.5418 A.) and nickel filter and data are given in Angstrom units. The d-spacings are not corrected for film shrinkage. The correction ordinarily is small and in general is less than either the variation in spacing arising from differences in experimental technique of

  20. Reactor production of Thorium-229.

    PubMed

    Hogle, Susan; Boll, Rose Ann; Murphy, Karen; Denton, David; Owens, Allison; Haverlock, Tamara J; Garland, Marc; Mirzadeh, Saed

    2016-08-01

    Limited availability of (229)Th for clinical applications of (213)Bi necessitates investigation of alternative production routes. In reactor production, (229)Th is produced from neutron transmutation of (226)Ra, (228)Ra, (227)Ac and (228)Th. Irradiations of (226)Ra, (228)Ra, and (227)Ac targets at the Oak Ridge National Laboratory High Flux Isotope Reactor result in yields of (229)Th at 26 days of 74.0±7.4MBq/g, 260±10MBq/g, and 1200±50MBq/g, respectively. Intermediate radionuclide yields and cross sections are also studied. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Reactor production of Thorium-229

    SciTech Connect

    Boll, Rose Ann; Murphy, Karen E.; Denton, David L.; Tamara J. Haverlock; Garland, Marc A.; Mirzadeh, Saed; Hogle, Susan; Owens, Allison

    2016-05-03

    Limited availability of 229Th for clinical applications of 213Bi necessitates investigation of alternative production routes. In reactor production, 229Th is produced from neutron transmutation of 226Ra, 228Ra, 227Ac and 228Th. Here, we evaluate irradiations of 226Ra, 228Ra, and 227Ac targets at the ORNL High Flux Isotope Reactor.

  2. Reactor production of Thorium-229

    SciTech Connect

    Boll, Rose Ann; Murphy, Karen E.; Denton, David L.; Tamara J. Haverlock; Garland, Marc A.; Mirzadeh, Saed; Hogle, Susan; Owens, Allison

    2016-05-03

    Limited availability of 229Th for clinical applications of 213Bi necessitates investigation of alternative production routes. In reactor production, 229Th is produced from neutron transmutation of 226Ra, 228Ra, 227Ac and 228Th. Here, we evaluate irradiations of 226Ra, 228Ra, and 227Ac targets at the ORNL High Flux Isotope Reactor.

  3. Thorium: An energy source for the world of tomorrow

    NASA Astrophysics Data System (ADS)

    Revol, J.-P.

    2015-08-01

    To meet the tremendous world energy needs, systematic R&D has to be pursued to replace fossil fuels. Nuclear energy, which produces no green house gases and no air pollution, should be a leading candidate. How nuclear energy, based on thorium rather than uranium, could be an acceptable solution is discussed. Thorium can be used both to produce energy and to destroy nuclear waste. The thorium conference, organized by iThEC at CERN in October 2013, has shown that thorium is seriously considered by some major developing countries as a key element of their energy strategy. However, developed countries do not seem to move fast enough in that direction, while global cooperation is highly desirable in this domain. Thorium is not fissile. Various possible ways of using thorium will be reviewed. However, an elegant option is to drive an "Accelerator Driven System (ADS)" with a proton accelerator, as suggested by Nobel Prize laureate Carlo Rubbia .

  4. Thoron-meso-tartaric acid system for determination of thorium

    USGS Publications Warehouse

    Fletcher, M.H.; Grimaldi, F.S.; Jenkins, L.B.

    1957-01-01

    In the spectrophotometric determination of thorium with thoron, mesotartaric acid is used as a masking reagent for zirconium. The effects of different experimental variables such as the concentrations of the reagents, time, and temperature, and the behavior of 35 ions which might be present in thorium ores are discussed. A dilution procedure is given for the direct determination of thorium in zircon (ZrSiO4) that is also generally applicable to other materials.

  5. SALICYLATE PROCESS FOR THORIUM SEPARATION FROM RARE EARTHS

    DOEpatents

    Cowan, G.A.

    1959-08-25

    The separation of thorium from rare earths is accomplished by forming an aqueous solution of salts of thorium and rare earths and sufficient acetate buffer to provide a pH of between 2 and 5, adding an ammonium salicylate to the aqueous buffered solution, contacting the resultant solution with a substantially water-immiscible organic solvent mixture of an ether and an ester, and separating the solvent extract phase containing thorium salicylate from the aqueous phase containing the rare earths.

  6. Thorium sorption from wastes of loparite concentrate chlorination

    SciTech Connect

    Kudryavskii, Yu.P.; Belkin, A.V.

    1987-03-01

    Thorium sorption on KFP-12 cation-exchange resin from solutions of spent melts from the salt-trickling filter in loparite concentrate chlorination has been studied by full trifactorial experiment. Calculated regression equations enable us to suggest that sorption should be carried out from acidic solutions where the iron ions are prereduced to the bivalent state. It has been shown that the degree of thorium purification diminishes and the working thorium sorption capacity increases with rise of temperature.

  7. Feasibility of recycling thorium in a fusion-fission hybrid/PWR symbiotic system

    SciTech Connect

    Josephs, J.M.

    1980-12-31

    A study was made of the economic impact of high levels of radioactivity in the thorium fuel cycle. The sources of this radioactivity and means of calculating the radioactive levels at various stages in the fuel cycle are discussed and estimates of expected levels are given. The feasibility of various methods of recycling thorium is discussed. These methods include direct recycle, recycle after storage for 14 years to allow radioactivity to decrease, shortening irradiation times to limit radioactivity build up, and the use of the window in time immediately after reprocessing where radioactivity levels are diminished. An economic comparison is made for the first two methods together with the throwaway option where thorium is not recycled using a mass energy flow model developed for a CTHR (Commercial Tokamak Hybrid Reactor), a fusion fission hybrid reactor which serves as fuel producer for several PWR reactors. The storage option is found to be most favorable; however, even this option represents a significant economic impact due to radioactivity of 0.074 mills/kW-h which amounts to $4 x 10/sup 9/ over a 30 year period assuming a 200 gigawatt supply of electrical power.

  8. Concentration and purification of plutonium or thorium

    DOEpatents

    Hayden, John A.; Plock, Carl E.

    1976-01-01

    In this invention a first solution obtained from such as a plutonium/thorium purification process or the like, containing plutonium (Pu) and/or thorium (Th) in such as a low nitric acid (HNO.sub.3) concentration may have the Pu and/or Th separated and concentrated by passing an electrical current from a first solution having disposed therein an anode to a second solution having disposed therein a cathode and separated from the first solution by a cation permeable membrane, the Pu or Th cation permeating the cation membrane and forming an anionic complex within the second solution, and electrical current passage affecting the complex formed to permeate an anion membrane separating the second solution from an adjoining third solution containing disposed therein an anode, thereby effecting separation and concentration of the Pu and/or Th in the third solution.

  9. Accelerator breeder with uranium, thorium target

    SciTech Connect

    Takahashi, H.; Powell, J.; Kouts, H.

    1983-01-01

    An accelerator breeder, that uses a low-enriched fuel as the target material, can produce substantial amounts of fissile material and electric power. A study of H/sub 2/O- and D/sub 2/O-cooled, UO/sub 2/, U, (depleted U), or thorium indicates that U-metal fuel produces a good fissile production rate and electrical power of about 60% higher than UO/sub 2/ fuel. Thorium fuel has the same order of magnitude as UO/sub 2/ fuel for fissile-fuel production, but the generating electric power is substantially lower than in a UO/sub 2/ reactor. Enriched UO/sub 2/ fuel increases the generating electric power but not the fissile-material production rate. The Na-cooled breeder target has many advantages over the H/sub 2/O-cooled breeder target.

  10. Infrared emission spectra or uranium and thorium

    SciTech Connect

    Palmer, B.A.; Phillips, M.V.; Engleman, R. Jr.

    1983-01-01

    The region between 1 and 5.5 ..mu..m has been observed with a high-resolution Fourier transform spectrometer. See-through hollow cathode lamps with calcium fluoride windows were operated at high current. Special precautions were required to minimize interference by blackbody radiation from the hot cathode. Observed lines were measured to an absolute accuracy of about 0.001 cm/sup -1/ and about 5% relative intensity accuracy. The argon carrier gas lines were readily distinguished by their much wider Doppler-broadened linewidths. Many lines were assigned to neutral or singly-ionized thorium on the basis of predicted transition wavenumbers calculated from accurate level lists. However, many lines remain to be assigned. This new spectral data connects to, and extends similar, spectral information given in our uranium and thorium atlases which cover the ultraviolet and visible regions.

  11. Thorium isotopic analysis by alpha spectrometry.

    PubMed

    Gingell, T

    2001-01-01

    The technique of alpha spectrometry is used to detect alpha particles and to determine their energy. In this way the technique is able to provide simultaneously quantitative information (i.e. the activity) and qualitative information (the identity) on any radionuclide that emits an alpha particle. The longer-lived naturally occurring isotopes of thorium are all alpha emitters so the technique can be used to quantify them directly and this is extremely important if radiation doses due to intakes of these isotopes into the body are to be accurately assessed. The principle of the technique is discussed, its advantages and disadvantages, and the instrumentation that is commonly used today. The need for radiochemical separation is discussed and illustrated by reference to analysis procedures in current use for thorium isotopic analysis. Practical issues such as detection limits, quality control procedures. sample throughput and cost will be covered.

  12. Nitrite complexes of uranium and thorium.

    PubMed

    Dulong, Florian; Pouessel, Jacky; Thuéry, Pierre; Berthet, Jean-Claude; Ephritikhine, Michel; Cantat, Thibault

    2013-03-25

    The first examples of inorganic nitrite complexes of the natural actinides are described, including the structures of the homoleptic thorium(IV) [PPh(4)](2)[Th(NO(2))(6)] and the uranyl(VI) [PPh(4)](2)[UO(2)(NO(2))(4)] complexes; the nitrite ligand can adopt two different coordination modes in the coordination sphere of the uranyl ion and is unstable towards reduction.

  13. Thorium dioxide: properties and nuclear applications

    SciTech Connect

    Belle, J.; Berman, R.M.

    1984-01-01

    This is the sixth book on reactor materials published under sponsorship of the Naval Reactors Office of the United States Department of Energy, formerly the United States Atomic Energy Commission. This book presents a comprehensive compilation of the most significant properties of thorium dioxide, much like the book Uranium Dioxide: Properties and Nuclear Applications presented information on the fuel material used in the Shippingport Pressurized Water Reactor core.

  14. Thoron-tartaric acid systems for spectrophotometric determination of thorium

    USGS Publications Warehouse

    Grimaldi, F.S.; Fletcher, M.H.

    1956-01-01

    Thoron is commonly used for the spectrophotometric determination of thorium. An undesirable feature of its use is its high sensitivity to zirconium. This study describes the use of tartaric acid as a masking reagent for zirconium. Three tartaric acid-thoron systems, developed for the determination of thorium, differ with respect to the concentrations of thoron and tartaric acid. Mesotartaric acid, used in one of the systems, is most effective in masking zirconium. The behavior of rarer elements, usually associated with thorium ores, is determined in two systems, and a dilution method is described for the direct determination of thorium in monazite concentrates.

  15. Accelerator-driven thorium-cycle fission power

    NASA Astrophysics Data System (ADS)

    Sattarov, Akhdiyor

    2009-10-01

    A flux-coupled stack of superconducting isochronous cyclotrons could be used to drive thorium-cycle fission power. The 800 MeV proton beams produce fast neutrons through spallation, then the fast neutrons transmute the thorium into uranium and drive fission. The thorium reactor would provide GW electric power, eat its own long-lived waste, run for 7 years between core accesses, operate below criticality, and be stable against melt-down. Reserves of thorium are sufficient to provide the world's energy needs for a thousand years.

  16. ADSORPTION METHOD FOR SEPARATING THORIUM VALUES FROM URANIUM VALUES

    DOEpatents

    Boyd, G.E.; Russell, E.R.; Schubert, J.

    1959-08-01

    An improved ion exchange method is described for recovery of uranium and thorium values as separate functions from an aqueous acidic solution containing less than 10/sup -3/ M thorium ions and between 0.1 and 1 M uranyl ions. The solution is passed through a bed of cation exchange resin in the acid form to adsorb all the thorium ions and a portion of the uranyl ions. The uranium is eluted by means of aqueous 0.1 to 0.4 M sulfuric acid. The thorium may then be stripped from the resin by elution with aqueous 0.5 M oxalic acid.

  17. Matrix infrared spectroscopic and density functional theoretical investigations on thorium and uranium atom reactions with dimethyl ether.

    PubMed

    Gong, Yu; Andrews, Lester

    2011-11-14

    Reactions of laser-ablated thorium and uranium atoms with dimethyl ether were investigated using matrix isolation infrared spectroscopy. Four types of reaction products for both uranium and thorium were identified using deuterium substituted samples as well as density functional frequency and energy calculations. Ground state uranium and thorium atoms react with dimethyl ether spontaneously to give the M(CH(3)OCH(3)) complexes (M = Th, U) on annealing, which are predicted to have C(2v) symmetry with triplet (Th) and quintet (U) ground states. Subsequent visible irradiation produces the divalent CH(3)OThCH(3) and CH(3)OUCH(3) insertion products with singlet and quintet states lowest in energy. Further UV irradiation induces isomerization of the CH(3)OMCH(3) molecules to the (CH(3))(2)MO isomers with M=O double bonds and pyramidal structures. In the presence of another dimethyl ether reagent, evidence for (CH(3)O)(2)M(CH(3))(2) molecules is also produced upon UV irradiation.

  18. A PWR Thorium Pin Cell Burnup Benchmark

    SciTech Connect

    Weaver, Kevan Dean; Zhao, X.; Pilat, E. E; Hejzlar, P.

    2000-05-01

    As part of work to evaluate the potential benefits of using thorium in LWR fuel, a thorium fueled benchmark comparison was made in this study between state-of-the-art codes, MOCUP (MCNP4B + ORIGEN2), and CASMO-4 for burnup calculations. The MOCUP runs were done individually at MIT and INEEL, using the same model but with some differences in techniques and cross section libraries. Eigenvalue and isotope concentrations were compared on a PWR pin cell model up to high burnup. The eigenvalue comparison as a function of burnup is good: the maximum difference is within 2% and the average absolute difference less than 1%. The isotope concentration comparisons are better than a set of MOX fuel benchmarks and comparable to a set of uranium fuel benchmarks reported in the literature. The actinide and fission product data sources used in the MOCUP burnup calculations for a typical thorium fuel are documented. Reasons for code vs code differences are analyzed and discussed.

  19. Thorium in the workplace measurement intercomparison.

    PubMed

    Modna, D K; Jerome, S M; White, M A; Woods, M J

    2000-01-01

    The monitoring of radionuclides in the nuclear industry has been recognized as the most straightforward way of assessing health and safety issues associated with the exposure of the workforce to potentially harmful radiation doses. Much of this is achieved by measurements in the workplace itself and by the bioassay and monitoring of workers in the industry. However, there also exists a significant 'non-nuclear' industry where workers are exposed to radioactive materials, for example where this involves thorium, which is made wide use of in the aerospace and other high technology industries. As such work involves the processing of thorium bearing materials, the workforce is potentially exposed to 232Th and its daughter nuclides. Thus, to monitor the workforce effectively, it is important to be able to measure both 232Th and the decay products of 232Th where they are in an unknown state of radioactive equilibrium and this is where monitoring laboratories may experience some difficulty. Accordingly, the Health and Safety Laboratory in the UK has organized a EC wide project on the monitoring of thorium in the 'non-nuclear' workplace; this project is currently ongoing. We report the results of the first intercomparison of this project involving two solutions of 232Th, one in radioactive equilibrium and one not in equilibrium with its daughters. The results are presented with some comments on how this intercomparison has progressed and how these first results will inform the rest of the project.

  20. Self-Sustaining Thorium Boiling Water Reactors

    SciTech Connect

    Greenspan, Ehud; Gorman, Phillip M.; Bogetic, Sandra; Seifried, Jeffrey E.; Zhang, Guanheng; Varela, Christopher R.; Fratoni, Massimiliano; Vijic, Jasmina J.; Downar, Thomas; Hall, Andrew; Ward, Andrew; Jarrett, Michael; Wysocki, Aaron; Xu, Yunlin; Kazimi, Mujid; Shirvan, Koroush; Mieloszyk, Alexander; Todosow, Michael; Brown, Nicolas; Cheng, Lap

    2015-03-15

    The primary objectives of this project are to: Perform a pre-conceptual design of a core for an alternative to the Hitachi proposed fuel-self- sustaining RBWR-AC, to be referred to as a RBWR-Th. The use of thorium fuel is expected to assure negative void coefficient of reactivity (versus positive of the RBWR-AC) and improve reactor safety; Perform a pre-conceptual design of an alternative core to the Hitachi proposed LWR TRU transmuting RBWR-TB2, to be referred to as the RBWR-TR. In addition to improved safety, use of thorium for the fertile fuel is expected to improve the TRU transmutation effectiveness; Compare the RBWR-Th and RBWR-TR performance against that of the Hitachi RBWR core designs and sodium cooled fast reactor counterparts - the ARR and ABR; and, Perform a viability assessment of the thorium-based RBWR design concepts to be identified along with their associated fuel cycle, a technology gap analysis, and a technology development roadmap. A description of the work performed and of the results obtained is provided in this Overview Report and, in more detail, in the Attachments. The major findings of the study are summarized.

  1. Thorium lung burdens of mineral sands workers.

    PubMed

    Terry, K W; Hewson, G S

    1995-08-01

    Thorium lung burdens have been measured in workers in the dry separation plants operated by the mineral sands industry in Western Australia. The data have been compared with historical employment records of the worker's exposure to thorium-bearing airborne dusts in order to assess the reliability of personal air sampling and with the predictions of the new Task Group lung model. The thoron exhaled in the breath of 62 workers was measured using a double filter tube. Six of the workers also underwent in-vivo gamma counting to determine their thorium lung burden. A thoron exhalation rate of 4.7% was obtained from a comparison of the two data sets. The estimated thorium lung burdens from the thoron-in-breath measurements had a geometric mean value of 10 Bq. The workers had a geometric mean employment period in the industry of 9.2 y and a geometric mean total inhaled alpha activity of 9,000 Bq, estimated from contemporary personal air sampling data and a retrospective assessment of previous workplace conditions. This exposure corresponds to a mean daily intake of 232Th of 0.45 Bq. Predictions from the new Task Group lung model indicate that, for the 45 workers with a thorium lung burden in excess of the minimum detectable level (6 Bq), the daily intake of 232Th is a factor of 1.6 higher than expected. This result suggests that previous intake of radioactive dust was higher than generally assumed for some workers. The application of the new Task Group lung models to the bioassay data results in an estimated mean annual committed effective dose for the workers of 8 mSv. Two workers (3%) were found to have been exposed for many years in excess of the 50 mSv y-1 annual limit for occupational exposure, while eight workers (13%) exceeded the ICRP's proposed new occupational standard of an average of 20 mSv y-1. All eight had been employed for more than 6 y and the majority of their exposure was attributed to early employment years, prior to extensive workplace improvements in

  2. Thorium-uranium fission radiography

    NASA Technical Reports Server (NTRS)

    Haines, E. L.; Weiss, J. R.; Burnett, D. S.; Woolum, D. S.

    1976-01-01

    Results are described for studies designed to develop routine methods for in-situ measurement of the abundance of Th and U on a microscale in heterogeneous samples, especially rocks, using the secondary high-energy neutron flux developed when the 650 MeV proton beam of an accelerator is stopped in a 42 x 42 cm diam Cu cylinder. Irradiations were performed at three different locations in a rabbit tube in the beam stop area, and thick metal foils of Bi, Th, and natural U as well as polished silicate glasses of known U and Th contents were used as targets and were placed in contact with mica which served as a fission track detector. In many cases both bare and Cd-covered detectors were exposed. The exposed mica samples were etched in 48% HF and the fission tracks counted by conventional transmitted light microscopy. Relative fission cross sections are examined, along with absolute Th track production rates, interaction tracks, and a comparison of measured and calculated fission rates. The practicality of fast neutron radiography revealed by experiments to data is discussed primarily for Th/U measurements, and mixtures of other fissionable nuclei are briefly considered.

  3. Thorium-uranium fission radiography

    NASA Technical Reports Server (NTRS)

    Haines, E. L.; Weiss, J. R.; Burnett, D. S.; Woolum, D. S.

    1976-01-01

    Results are described for studies designed to develop routine methods for in-situ measurement of the abundance of Th and U on a microscale in heterogeneous samples, especially rocks, using the secondary high-energy neutron flux developed when the 650 MeV proton beam of an accelerator is stopped in a 42 x 42 cm diam Cu cylinder. Irradiations were performed at three different locations in a rabbit tube in the beam stop area, and thick metal foils of Bi, Th, and natural U as well as polished silicate glasses of known U and Th contents were used as targets and were placed in contact with mica which served as a fission track detector. In many cases both bare and Cd-covered detectors were exposed. The exposed mica samples were etched in 48% HF and the fission tracks counted by conventional transmitted light microscopy. Relative fission cross sections are examined, along with absolute Th track production rates, interaction tracks, and a comparison of measured and calculated fission rates. The practicality of fast neutron radiography revealed by experiments to data is discussed primarily for Th/U measurements, and mixtures of other fissionable nuclei are briefly considered.

  4. Small-area thorium features on the lunar surface

    NASA Astrophysics Data System (ADS)

    Lawrence, D. J.; Elphic, R. C.; Feldman, W. C.; Prettyman, T. H.; Gasnault, O.; Maurice, S.

    2003-09-01

    Using an improved understanding of the Lunar Prospector Gamma-Ray Spectrometer (LP-GRS) spatial footprint, we have derived a new map of global thorium abundances on the lunar surface. This map has a full-width, half-maximum spatial resolution of ~(80 km)2 and is mapped on the lunar surface using 0.5° × 0.5° pixels. This map has allowed the identification and classification of 42 small-area (<[80 km]2) thorium features across the lunar surface. Twenty of these features, all of which are located in the nearside Procellarum KREEP terrane, show a thorium-iron anticorrelation that is indicative of mixing between mare basalts and thorium-rich mafic impact-melt breccias (MIB). However, there exists at least one example of a farside location (Dewar crater) that appears to have abundances similar to the thorium-rich MIBs. This new map has also allowed the identification of mare basalts having high thorium abundances (>3 μg/g) in southwestern Mare Tranquillitatis, near the Apollo 11 landing site. With our better understanding of the LP-GRS spatial footprint, we have been able to constrain the surface thorium abundance at the Compton/Belkovich thorium anomaly to 40-55 μg/g, which is higher than any other measured location on the lunar surface and higher than most samples. Finally, using 1 km/pixel FeO abundances from Clementine and LP-GRS spatial footprint information, we have been able to obtain plausible thorium distributions around Kepler crater at a resolution of 1 km/pixel. The materials around Kepler crater appear to be a relatively simple mixing of thorium-rich MIB compositions and high-thorium mare basalts.

  5. REGENERATION OF FISSION-PRODUCT-CONTAINING MAGNESIUM-THORIUM ALLOYS

    DOEpatents

    Chiotti, P.

    1964-02-01

    A process of regenerating a magnesium-thorium alloy contaminated with fission products, protactinium, and uranium is presented. A molten mixture of KCl--LiCl-MgCl/sub 2/ is added to the molten alloy whereby the alkali, alkaline parth, and rare earth fission products (including yttrium) and some of the thorium and uranium are chlorinated and

  6. Fuel Breeding and Core Behavior Analyses on In Core Fuel Management of Water Cooled Thorium Reactors

    SciTech Connect

    Permana, Sidik; Sekimoto, Hiroshi; Waris, Abdul; Subhki, Muhamad Nurul; Ismail,

    2010-12-23

    Thorium fuel cycle with recycled U-233 has been widely recognized having some contributions to improve the water-cooled breeder reactor program which has been shown by a feasible area of breeding and negative void reactivity which confirms that fissile of 233U contributes to better fuel breeding and effective for obtaining negative void reactivity coefficient as the main fissile material. The present study has the objective to estimate the effect of whole core configuration as well as burnup effects to the reactor core profile by adopting two dimensional model of fuel core management. About more than 40 months of cycle period has been employed for one cycle fuel irradiation of three batches fuel system for large water cooled thorium reactors. All position of fuel arrangement contributes to the total core conversion ratio which gives conversion ratio less than unity of at the BOC and it contributes to higher than unity (1.01) at the EOC after some irradiation process. Inner part and central part give the important part of breeding contribution with increasing burnup process, while criticality is reduced with increasing the irradiation time. Feasibility of breeding capability of water-cooled thorium reactors for whole core fuel arrangement has confirmed from the obtained conversion ratio which shows higher than unity. Whole core analysis on evaluating reactivity change which is caused by the change of voided condition has been employed for conservative assumption that 100% coolant and moderator are voided. It obtained always a negative void reactivity coefficient during reactor operation which shows relatively more negative void coefficient at BOC (fresh fuel composition), and it becomes less negative void coefficient with increasing the operation time. Negative value of void reactivity coefficient shows the reactor has good safety properties in relation to the reactivity profile which is the main parameter in term of criticality safety analysis. Therefore, this

  7. The Use of Thorium within the Nuclear Power Industry - 13472

    SciTech Connect

    Miller, Keith

    2013-07-01

    Thorium is 3 to 4 times more abundant than uranium and is widely distributed in nature as an easily exploitable resource in many countries. Unlike natural uranium, which contains ∼0.7% fissile {sup 235}U isotope, natural thorium does not contain any fissile material and is made up of the fertile {sup 232}Th isotope only. Therefore thorium and thorium-based fuel as metal, oxide or carbide, has been utilized in combination with fissile {sup 235}U or {sup 239}Pu in nuclear research and power reactors for conversion to fissile {sup 233}U, thereby enlarging fissile material resources. During the pioneering years of nuclear energy, from the mid 1950's to mid 1970's, there was considerable interest worldwide to develop thorium fuels and fuel cycles in order to supplement uranium reserves. Thorium fuels and fuel cycles are particularly relevant to countries having large thorium deposits but very limited uranium reserves for their long term nuclear power programme. The feasibility of thorium utilization in high temperature gas cooled reactors (HTGR), light water reactors (LWR), pressurized heavy water reactors (PHWRs), liquid metal cooled fast breeder reactors (LMFBR) and molten salt breeder reactors (MSBR) were demonstrated. The initial enthusiasm for thorium fuels and fuel cycles was not sustained among the developing countries later, due to new discovery of uranium deposits and their improved availability. However, in recent times, the need for proliferation-resistance, longer fuel cycles, higher burnup, and improved waste form characteristics, reduction of plutonium inventories and in situ use of bred-in fissile material has led to renewed interest in thorium-based fuels and fuel cycles. (authors)

  8. Structural and mechanical properties of thorium carbide

    SciTech Connect

    Aynyas, Mahendra; Pataiya, Jagdeesh; Arya, B. S.; Singh, A.; Sanyal, S. P.

    2015-06-24

    We have investigated the cohesive energies, equilibrium lattice constants, pressure-volume relationship, phase transition pressure and elastic constant for thorium carbide using an interionic potential theory with modified ionic charge, which includes Coulomb screening effect due to d-electrons. This compound undergoes structural phase transition from NaCl (B{sub 1}) to CsCl (B{sub 2}) structure at high pressure 40 GPa. We have also calculated bulk, Young, and shear moduli, Poisson ratio and anisotropic ratio in NaCl (B{sub 1}) structure and compared them with other experimental and theoretical results which show a good agreement.

  9. Principal thorium resources in the United States

    USGS Publications Warehouse

    Staatz, Mortimer Hay; Armbrustmacher, T.J.; Olson, J.C.; Brownfield, I.K.; Brock, M.R.; Lemons, J.F.; Coppa, L.V.; Clingan, B.V.

    1979-01-01

    Resources were assessed for thorium in the higher grade and better known deposits in the United States in: (1) veins, (2) massive carbonatites, (3) stream placers of North and South Carolina, and (4) disseminated deposits. Thorium resources for the first three categories were divided into reserves and probable potential resources. Each of these then were separated into the following cost categories: (1) the amount of ThO2 producible at less than $15 per pound, (2) the amount producible at between $15 and $30 per pound, and (3) the amount producible at more than $50 per pound. The type of mining and milling needed at each deposit determines the capital, operating, and fixed costs of both mining and milling. Costs start with the clearing of land and are carried through to the final product, which for all deposits is ThO2. Capital costs of mining are affected most by the type of mining and the size of the mine. Those of milling are affected most by the kind of mill, its size, and whether or not extra circuits are needed for the separation of rare earths or some other byproduct. Veins, massive carbonatites, and stream placers of North and South Carolina have reserves of 188,000 short tons of ThO2 and probable potential resources of 505,000 tons of ThO2. Approximately half of the reserves and probable potential resources can be produced at less than $30 per pound of ThO2. Veins are the highest grade source in the United States and have total reserves of 142,000 tons of ThO2 and probable potential resources of 343,000 tons. About 90 percent of the reserves and 91 percent of the probable potential resources can be produced at less than $15 per pound of ThO2. Seven vein districts were evaluated: (1) Lemhi Pass, Mont.-Idaho, (2) Wet Mountains, Colo., (3) Powderhorn, Colo., (4) Hall Mountain, Idaho, (5) Diamond Creek, Idaho, (6) Bear Lodge Mountains, Wyo. and (7) Mountain Pass, Calif. Eighty-seven percent of the total reserves and probable potential resources are in the

  10. 49 CFR 173.434 - Activity-mass relationships for uranium and natural thorium.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... natural thorium. 173.434 Section 173.434 Transportation Other Regulations Relating to Transportation....434 Activity-mass relationships for uranium and natural thorium. The table of activity-mass relationships for uranium and natural thorium are as follows: Thorium and uranium enrichment 1(Wt% 235 U present...

  11. 49 CFR 173.434 - Activity-mass relationships for uranium and natural thorium.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... natural thorium. 173.434 Section 173.434 Transportation Other Regulations Relating to Transportation....434 Activity-mass relationships for uranium and natural thorium. The table of activity-mass relationships for uranium and natural thorium are as follows: Thorium and uranium enrichment 1(Wt% 235 U present...

  12. Crystal chemistry of thorium nitrates and chromates

    SciTech Connect

    Sigmon, Ginger E.; Burns, Peter C.

    2010-07-15

    The structures and infrared spectra of six novel thorium compounds are reported. Th(NO{sub 3}){sub 2}(OH){sub 2}(H{sub 2}O){sub 2} (1) crystallizes in space group C2/c, a=14.050(1), b=8.992(7), c=5.954(5) A, {beta}=101.014(2){sup o}. K{sub 2}Th(NO{sub 3}){sub 6} (2), P-3, a=13.606(1), c=6.641(6) A. (C{sub 12}H{sub 28}N){sub 2}Th(NO{sub 3}){sub 6} (3), P2{sub 1}/c, a=14.643(4), b=15.772(5), c=22.316(5) A, {beta}=131.01(1){sup o}. KTh(NO{sub 3}){sub 5}(H{sub 2}O){sub 2} (4), P2{sub 1}/c, a=10.070(8), b=12.731(9), c=13.231(8) A, {beta}=128.647(4){sup o}. Th(CrO{sub 4}){sub 2}(H{sub 2}O){sub 2} (5), P2{sub 1}/n, a=12.731(1), b=9.469(8), c=12.972(1) A, {beta}=91.793(2){sup o}. K{sub 2}Th{sub 3}(CrO{sub 4}){sub 7}(H{sub 2}O){sub 10} (6), Ama2, a=19.302(8), b=15.580(6), c=11.318(6) A. The coordination polyhedra about Th in these structures are diverse. Th is coordinated by 9 O atoms in 5 and 6, seven of which are from monodentate (CrO{sub 4}) tetrahedra and two are (H{sub 2}O). The Th in compound 1 is coordinated by ten O atoms, four of which are O atoms of two bidentate (NO{sub 3}) triangles and six of which are (OH) and (H{sub 2}O). In compounds 2, 3 and 4 the Th is coordinate by 12 O atoms. In 2 and 3 there are six bidentate (NO{sub 3}) triangles, and in 4 ten of the O atoms are part of five bidentate (NO{sub 3}) triangles and the others are (H{sub 2}O) groups. The structural units of these compounds consist of a chain of thorium and nitrate polyhedra (1), isolated thorium hexanitrate clusters (2, 3), an isolated thorium pentanitrate dihydrate cluster (4), and a sheet (6) and framework (5) of thorium and chromate polyhedra. These structures illustrate the complexity inherent in the crystal chemistry of Th. - Graphical Abstract: The structures and infrared spectra of four new Th nitrates and two Th chromates are reported. The coordination numbers of the Th cations range from nine to 12 in these compounds. Structural units consist of isolated clusters, chains, sheets and

  13. Evolution of uranium and thorium minerals

    NASA Astrophysics Data System (ADS)

    Hazen, R. M.; Ewing, R. C.; Sverjensky, D. A.

    2009-12-01

    The origins and near-surface distributions of the approximately 250 known uranium and/or thorium minerals elucidate principles of mineral evolution. This history can be divided into four phases. The first, from ~4.5 to 3.5 Ga, involved successive concentrations of uranium and thorium from their initial uniform trace distribution into magmatic-related fluids from which the first U4+ and Th4+ minerals, uraninite (UO2), thorianite (ThO2) and coffinite (USiO4), precipitated in the crust. The second period, from ~3.5 to 2.2 Ga, saw the formation of large low-grade concentrations of detrital uraninite (containing several weight percent Th) in the Witwatersrand-type quartz-pebble conglomerates deposited in a highly anoxic fluvial environment. Abiotic alteration of uraninite and coffinite, including radiolysis and auto-oxidation caused by radioactive decay and the formation of helium from alpha particles, may have resulted in the formation of a limited suite of uranyl oxide-hydroxides. Earth’s third phase of uranium mineral evolution, during which most known U minerals first precipitated from reactions of soluble uranyl (U6+O2)2+ complexes, followed the Great Oxidation Event (GOE) at ~2.2 Ga and thus was mediated indirectly by biologic activity. Most uraninite deposited during this phase was low in Th and precipitated from saline and oxidizing hydrothermal solutions (100 to 300°C) transporting (UO2)2+-chloride complexes. Examples include the unconformity- and vein-type U deposits (Australia and Canada) and the unique Oklo natural nuclear reactors in Gabon. The onset of hydrothermal transport of (UO2)2+ complexes in the upper crust may reflect the availability of CaSO4-bearing evaporites after the GOE. During this phase, most uranyl minerals would have been able to form in the O2-bearing near-surface environment for the first time through weathering processes. The fourth phase of uranium mineralization began approximately 400 million years ago, as the rise of land plants

  14. Environmental control technology for mining, milling, and refining thorium

    SciTech Connect

    Weakley, S.A.; Blahnik, D.E.; Young, J.K.; Bloomster, C.H.

    1980-02-01

    The purpose of this report is to evaluate, in terms of cost and effectiveness, the various environmental control technologies that would be used to control the radioactive wastes generated in the mining, milling, and refining of thorium from domestic resources. The technologies, in order to be considered for study, had to reduce the radioactivity in the waste streams to meet Atomic Energy Commission (10 CFR 20) standards for natural thorium's maximum permissible concentration (MPC) in air and water. Further regulatory standards or licensing requirements, either federal, state, or local, were not examined. The availability and cost of producing thorium from domestic resources is addressed in a companion volume. The objectives of this study were: (1) to identify the major waste streams generated during the mining, milling, and refining of reactor-grade thorium oxide from domestic resources; and (2) to determine the cost and levels of control of existing and advanced environmental control technologies for these waste streams. Six potential domestic deposits of thorium oxide, in addition to stockpiled thorium sludges, are discussed in this report. A summary of the location and characteristics of the potential domestic thorium resources and the mining, milling, and refining processes that will be needed to produce reactor-grade thorium oxide is presented in Section 2. The wastes from existing and potential domestic thorium oxide mines, mills, and refineries are identified in Section 3. Section 3 also presents the state-of-the-art technology and the costs associated with controlling the wastes from the mines, mills, and refineries. In Section 4, the available environmental control technologies for mines, mills, and refineries are assessed. Section 5 presents the cost and effectiveness estimates for the various environmental control technologies applicable to the mine, mill, and refinery for each domestic resource.

  15. RECOVERY OF URANIUM AND THORIUM FROM AQUEOUS SOLUTIONS

    DOEpatents

    Calkins, G.D.

    1958-06-10

    >A process is described for the recovery of uranium and thorium from monazite sand, which is frequently processed by treating it with a hot sodium hydroxide solution whereby a precipitate forms consisting mainly of oxides or hydroxides of the rare earths, thorium and uranium. The precipitate is dissolved in mineral acid, and the acid solution is then neutralized to a pH value of between 5.2 and 6.2 whereby both the uranium and thorium precipitate as the hydroxides, while substantially all the rare earth metal values present remain in the solution. The uranium and thoriunn can then be separated by dissolving the precipitate in a solution containing a mixture of alkali carbonate and alkali bicarbonate: and contacting the carbonate solution with a strong-base anion exchange resin whereby the uranium values are adsorbed on the resin while the thorium remains in solution.

  16. RECOVERY OF THORIUM AND URANIUM VALUES FROM AQUEOUS SOLUTIONS

    DOEpatents

    Calkins, G.D.

    1958-02-18

    This patent deals with the separation and recovery of uranium from monazite sand. After initial treatment of the sand with sodium hydroxide, a precipitate is obtuined which contains the uranium, thorium, rare earths and some phosphorus. This precipitate is then dissolved in nitric acid. The bulk of the rare earths are removed from thls soiution by adding aa excess of alkali carbonate, causing precipitation of the rare earths together with part of the thorium present. The solution still contains a considerable amount of thorium, some rare earths, and practically all of the uranium originally present. Thorium and rare earth values are readily precipitated from such solution, and the uranium values thus isolated, by the addition of an excess hydrogen peroxide. The pH value of the solution is preferably adjusted to at least 9 prior to the addition of the peroxide.

  17. Neutron-activation analysis for thorium in zircon.

    PubMed

    Desai, H B; Parthasarathy, R; Das, M S

    1972-03-01

    The thorium content of zircons and standard rock samples was determined by neutron-activation analysis. The 310-keV photopeak activity of (233)Pa was enhanced by a prior chemical separation which removed interfering induced activities.

  18. Tables for determining lead, uranium, and thorium isotope ages

    NASA Technical Reports Server (NTRS)

    Schonfeld, E.

    1974-01-01

    Tables for determining lead, uranium, and thorium isotope ages are presented in the form of computer printouts. Decay constants, analytical expressions for the functions evaluated, and the precision of the calculations are briefly discussed.

  19. Structures of dimeric hydrolysis products of thorium.

    PubMed

    Wilson, Richard E; Skanthakumar, S; Sigmon, Ginger; Burns, Peter C; Soderholm, L

    2007-04-02

    Three unique thorium dimeric compounds have been crystallized from either direct hydrolysis of Th4+(aq)/HCl or titration of Th(OH)4(am) with Th(NO3)4(aq) and their structures determined using single-crystal X-ray diffraction. The compound [Th2(micro2-OH)2(NO3)6(H2O)6]H2O (1) is identical to that identified previously by Johansson. Two additional unreported compounds have been identified, [Th2(micro2-OH)2(NO3)4(H2O)8](NO3)2 (2) and [Th2(micro2-OH)2Cl2(H2O)12]Cl4.2H2O (3). 1 crystallizes in the monoclinic space group P21/c, with a = 6.792(2) A, b = 11.710(4) A, c = 13.778(5) A, and beta = 102.714(5) degrees and 2 crystallizes in the monoclinic space group P21/n, with a = 6.926(5) A, b = 7.207(1) A, c = 21.502(1) A, and beta = 96.380(1) degrees . The chloride-containing dimer, 3, crystallizes in triclinic P, with a = 8.080(2) A, b = 8.880(2) A, c = 9.013(2) A, alpha = 97.41(3) degrees , beta = 91.00(3), and gamma = 116.54(3) degrees . We also present high-energy X-ray scattering data demonstrating the presence of the hydroxo-bridged moiety in solution and discuss our findings in the context of known solid-state structures. The three structures demonstrate 11-, 10-, and 9-coordinate thorium, respectively, and coupled with the scattering experiments provide additional structural and chemical insight into tetravalent actinide hydrolysis.

  20. Electrical Relaxation in Calcium Fluoride Doped with Thorium and Zirconium.

    DTIC Science & Technology

    1986-09-01

    9, 1055 (1976). 4. M. Ouwerkerk , F. F. Veldkamp, N. H. Andersen, and J . Schoonman, Solid State Ionics, 16, 125 (1985). 5. S. F. Matar, J . M. Reau, P...AD-Al?2 366 ELECTRICAL RELAXATION IN CALCIUM FLUORIDE DOPED WITH L1/ THORIUM AND ZIRCONIUM(U) NAYRL ACADEMY ANNAPOLIS MD DEPT OF PHYSICS J J ...Fluoride Doped with Thorium and Zirconium by John J . Fontanella & Mary C. Wintersgill Prepared for Publication in Crystal Lattice Defects and Amorphous

  1. Method of synthesis of anhydrous thorium(IV) complexes

    DOEpatents

    Kiplinger, Jaqueline L; Cantat, Thibault

    2013-04-30

    Method of producing anhydrous thorium(IV) tetrahalide complexes, utilizing Th(NO.sub.3).sub.4(H.sub.2O).sub.x, where x is at least 4, as a reagent; method of producing thorium-containing complexes utilizing ThCl.sub.4(DME).sub.2 as a precursor; method of producing purified ThCl.sub.4(ligand).sub.x compounds, where x is from 2 to 9; and novel compounds having the structures: ##STR00001##

  2. Economics of large-scale thorium oxide production: assessment of domestic resources

    SciTech Connect

    Young, J.K.; Bloomster, C.H.; Enderlin, W.I.; Morgenstern, M.H.; Ballinger, M.Y.; Drost, M.K.; Weakley, S.A.

    1980-02-01

    The supply curve illustrates that sufficient amounts of thorium exist supply a domestic thorium-reactor economy. Most likely costs of production range from $3 to $60/lb ThO/sub 2/. Near-term thorium oxide resources include the stockpiles in Ohio, Maryland, and Tennessee and the thorite deposits at Hall Mountain, Idaho. Costs are under $10/lb thorium oxide. Longer term economic deposits include Wet Mountain, Colorado; Lemhi Pass, Idaho; and Palmer, Michigan. Most likely costs are under $20/lb thorium oxide. Long-term deposits include Bald Mountain, Wyoming; Bear Lodge, Wyoming; and Conway, New Hampshire. Costs approximately equal or exceed $50/lb thorium oxide.

  3. Toxicity of irradiated advanced heavy water reactor fuels.

    PubMed

    Priest, N D; Richardson, R B; Edwards, G W R

    2013-02-01

    The good neutron economy and online refueling capability of the CANDU® heavy water moderated reactor (HWR) enable it to use many different fuels such as low enriched uranium (LEU), plutonium, or thorium, in addition to its traditional natural uranium (NU) fuel. The toxicity and radiological protection methods for these proposed fuels, unlike those for NU, are not well established. This study uses software to compare the fuel composition and toxicity of irradiated NU fuel against those of two irradiated advanced HWR fuel bundles as a function of post-irradiation time. The first bundle investigated is a CANFLEX® low void reactor fuel (LVRF), of which only the dysprosium-poisoned central element, and not the outer 42 LEU elements, is specifically analyzed. The second bundle investigated is a heterogeneous high-burnup (LEU,Th)O(2) fuelled bundle, whose two components (LEU in the outer 35 elements and thorium in the central eight elements) are analyzed separately. The LVRF central element was estimated to have a much lower toxicity than that of NU at all times after shutdown. Both the high burnup LEU and the thorium fuel had similar toxicity to NU at shutdown, but due to the creation of such inhalation hazards as (238)Pu, (240)Pu, (242)Am, (242)Cm, and (244)Cm (in high burnup LEU), and (232)U and (228)Th (in irradiated thorium), the toxicity of these fuels was almost double that of irradiated NU after 2,700 d of cooling. New urine bioassay methods for higher actinoids and the analysis of thorium in fecal samples are recommended to assess the internal dose from these two fuels.

  4. OPTIMIZATION OF HETEROGENEOUS UTILIZATION OF THORIUM IN PWRS TO ENHANCE PROLIFERATION RESISTANCE AND REDUCE WASTE.

    SciTech Connect

    TODOSOW,M.; KAZIMI,M.

    2004-08-01

    Issues affecting the implementation, public perception and acceptance of nuclear power include: proliferation, radioactive waste, safety, and economics. The thorium cycle directly addresses the proliferation and waste issues, but optimization studies of core design and fuel management are needed to ensure that it fits within acceptable safety and economic margins. Typical pressurized water reactors, although loaded with uranium fuel, produce 225 to 275 kg of plutonium per gigawatt-year of operation. Although the spent fuel is highly radioactive, it nevertheless offers a potential proliferation pathway because the plutonium is relatively easy to separate, amounts to many critical masses, and does not present any significant intrinsic barrier to weapon assembly. Uranium 233, on the other hand, produced by the irradiation of thorium, although it too can be used in weapons, may be ''denatured'' by the addition of natural, depleted or low enriched uranium. Furthermore, it appears that the chemical behavior of thoria or thoria-urania fuel makes it a more stable medium for the geological disposal of the spent fuel. It is therefore particularly well suited for a once-through fuel cycle. The use of thorium as a fertile material in nuclear fuel has been of interest since the dawn of nuclear power technology due to its abundance and to potential neutronic advantages. Early projects include homogeneous mixtures of thorium and uranium oxides in the BORAX-IV, Indian Point I, and Elk River reactors, as well as heterogeneous mixtures in the Shippingport seed-blanket reactor. However these projects were developed under considerably different circumstances than those which prevail at present. The earlier applications preceded the current proscription, for non-proliferation purposes, of the use of uranium enriched to more than 20 w/o in {sup 235}U, and has in practice generally prohibited the use of uranium highly enriched in {sup 235}U. They were designed when the expected burnup of

  5. The influence of different hydroponic conditions on thorium uptake by Brassica juncea var. foliosa.

    PubMed

    Wang, Dingna; Zhou, Sai; Liu, Li; Du, Liang; Wang, Jianmei; Huang, Zhenling; Ma, Lijian; Ding, Songdong; Zhang, Dong; Wang, Ruibing; Jin, Yongdong; Xia, Chuanqin

    2015-05-01

    The effects of different hydroponic conditions (such as concentration of thorium (Th), pH, carbonate, phosphate, organic acids, and cations) on thorium uptake by Brassica juncea var. foliosa were evaluated. The results showed that acidic cultivation solutions enhanced thorium accumulation in the plants. Phosphate and carbonate inhibited thorium accumulation in plants, possibly due to the formation of Th(HPO4)(2+), Th(HPO4)2, or Th(OH)3CO3 (-) with Th(4+), which was disadvantageous for thorium uptake in the plants. Organic aids (citric acid, oxalic acid, lactic acid) inhibited thorium accumulation in roots and increased thorium content in the shoots, which suggested that the thorium-organic complexes did not remain in the roots and were beneficial for thorium transfer from the roots to the shoots. Among three cations (such as calcium ion (Ca(2+)), ferrous ion (Fe(2+)), and zinc ion (Zn(2+))) in hydroponic media, Zn(2+) had no significant influence on thorium accumulation in the roots, Fe(2+) inhibited thorium accumulation in the roots, and Ca(2+) was found to facilitate thorium accumulation in the roots to a certain extent. This research will help to further understand the mechanism of thorium uptake in plants.

  6. The crystal chemistry of four thorium sulfates

    SciTech Connect

    Albrecht, Amanda J.; Sigmon, Ginger E.; Moore-Shay, Laura; Wei, Rebecca; Dawes, Colleen; Szymanowski, Jennifer; Burns, Peter C.

    2011-07-15

    Four thorium sulfate compounds have been synthesized and characterized. [Th(SO{sub 4}){sub 2}(H{sub 2}O){sub 7}].2H{sub 2}O (ThS1) crystallizes in space group P2{sub 1}/m, a=7.2488(4), b=12.1798(7), c=8.0625(5) A, {beta}=98.245(1){sup o}; Na{sub 10}[Th{sub 2}(SO{sub 4}){sub 9}(H{sub 2}O){sub 2}].3H{sub 2}O (ThS2), Pna2{sub 1}, a=17.842(2), b=6.9317(8), c=27.550(3) A; Na{sub 2}[Th{sub 2}(SO{sub 4}){sub 5}(H{sub 2}O){sub 3}].H{sub 2}O (ThS3), C2/c, a=16.639(2), b=9.081(1), c=25.078(3) A, {beta}= 95.322(2){sup o}; [Th{sub 4}(SO{sub 4}){sub 7}(OH){sub 2}(H{sub 2}O){sub 6}].2H{sub 2}O (ThS4), Pnma, a=18.2127(9), b=11.1669(5), c=14.4705(7) A. In all cases the Th cations are coordinated by nine O atoms corresponding to SO{sub 4} tetrahedra, OH groups, and H{sub 2}O groups. The structural unit of ThS1 is an isolated cluster consisting of a single Th polyhedron with two monodentate SO{sub 4} tetrahedra and seven H{sub 2}O groups. A double-wide Th sulfate chain is the basis of ThS2. The structures of ThS3 and ThS4 are frameworks of Th polyhedra and sulfate tetrahedra, and each contains channels that extend through the framework. One of the Th cations in ThS3 is coordinated by a bidentate SO{sub 4} tetrahedron, and ThS4 is unusual in the presence of a pair of Th cations that share a polyhedral face. - Graphical abstract: The structures of four hydrous thorium sulfates are reported that have structural units consisting of finite clusters, chains, and frameworks. Highlights: > Four hydrous thorium sulfates have structural units consisting of finite clusters, chains, and frameworks. > In each the Th cations are coordinated by nine O atoms from SO{sub 4} tetrahedra, OH groups, and H{sub 2}O groups. > The details of the linkages of ThO{sub 9} polyhedra and sulfate tetrahedra vary considerably in these structures.

  7. Transuranic Waste Burning Potential of Thorium Fuel in a Fast Reactor - 12423

    SciTech Connect

    Wenner, Michael; Franceschini, Fausto; Ferroni, Paolo; Sartori, Alberto; Ricotti, Marco

    2012-07-01

    Westinghouse Electric Company (referred to as 'Westinghouse' in the rest of this paper) is proposing a 'back-to-front' approach to overcome the stalemate on nuclear waste management in the US. In this approach, requirements to further the societal acceptance of nuclear waste are such that the ultimate health hazard resulting from the waste package is 'as low as reasonably achievable'. Societal acceptability of nuclear waste can be enhanced by reducing the long-term radiotoxicity of the waste, which is currently driven primarily by the protracted radiotoxicity of the transuranic (TRU) isotopes. Therefore, a transition to a more benign radioactive waste can be accomplished by a fuel cycle capable of consuming the stockpile of TRU 'legacy' waste contained in the LWR Used Nuclear Fuel (UNF) while generating waste which is significantly less radio-toxic than that produced by the current open U-based fuel cycle (once through and variations thereof). Investigation of a fast reactor (FR) operating on a thorium-based fuel cycle, as opposed to the traditional uranium-based is performed. Due to a combination between its neutronic properties and its low position in the actinide chain, thorium not only burns the legacy TRU waste, but it does so with a minimal production of 'new' TRUs. The effectiveness of a thorium-based fast reactor to burn legacy TRU and its flexibility to incorporate various fuels and recycle schemes according to the evolving needs of the transmutation scenario have been investigated. Specifically, the potential for a high TRU burning rate, high U-233 generation rate if so desired and low concurrent production of TRU have been used as metrics for the examined cycles. Core physics simulations of a fast reactor core running on thorium-based fuels and burning an external TRU feed supply have been carried out over multiple cycles of irradiation, separation and reprocessing. The TRU burning capability as well as the core isotopic content have been characterized

  8. A neutron activation analysis procedure for the determination of uranium, thorium and potassium in geologic samples

    USGS Publications Warehouse

    Aruscavage, P. J.; Millard, H.T.

    1972-01-01

    A neutron activation analysis procedure was developed for the determination of uranium, thorium and potassium in basic and ultrabasic rocks. The three elements are determined in the same 0.5-g sample following a 30-min irradiation in a thermal neutron flux of 2??1012 n??cm-2??sec-1. Following radiochemical separation, the nuclides239U (T=23.5 m),233Th (T=22.2 m) and42K (T=12.36 h) are measured by ??-counting. A computer program is used to resolve the decay curves which are complex owing to contamination and the growth of daughter activities. The method was used to determine uranium, throium and potassium in the U. S. Geological Survey standard rocks DTS-1, PCC-1 and BCR-1. For 0.5-g samples the limits of detection for uranium, throium and potassium are 0.7, 1.0 and 10 ppb, respectively. ?? 1972 Akade??miai Kiado??.

  9. Accelerator Driven Nuclear Energy: The Thorium Option

    ScienceCinema

    Raja, Rajendran

    2016-07-12

    Conventional nuclear reactors use enriched Uranium as fuel and produce nuclear waste which needs to be stored away for over 10,000 years.   At the current rate of use, existing sources of Uranium will last for 50-100 years.  We describe a solution to the problem that uses particle accelerators to produce fast neutrons that can be used to burn existing nuclear waste and produce energy.  Such systems, initially proposed by Carlo Rubbia and collaborators in the 1990's, are being seriously considered by many countries as a possible solution to the green energy problem.  Accelerator driven reactors operate in a sub-critical regime and, thus, are safer and can obtain energy from plentiful elements such as Thorium-232 and Uranium-238. What is missing is the high intensity (10MW) accelerator that produces 1 GeV protons. We will describe scenarios which if implemented will make such systems a reality.  

  10. Activity ratios of thorium daughters in vivo

    SciTech Connect

    Toohey, R.E.; Rundo, J.; Sha, J.Y.; Essling, M.A.; Pedersen, J.C.; Slane, J.M.

    1984-01-01

    A computerized method of least squares has been used to analyze the /sup 228/Ac and /sup 212/Pb-/sup 212/Bi and daughter ..gamma..-ray spectra obtained in vivo from 133 former workers at a thorium refinery. In addition, the exhalation rate of /sup 220/Rn was determined for each subject and expressed as pCi of emanating /sup 224/Ra. This value was added to the /sup 212/Pb value determined from the ..gamma..-ray measurements to obtain the total /sup 224/Ra present, and the ratio of /sup 224/Ra to /sup 228/Ac was calculated. Values of the ratio ranged from 0.52 +- 0.32 to 2.1 +- 1.7, with a weighted mean of 0.92 +- 0.17. However, it appears that the ratio observed in a given case is characteristic for that case alone; the computed mean value may not be meaningful. The least squares fitting procedure and the overall calibration of the counting system were validated by measurements of /sup 224/Ra in the lungs of one subject postmortem, compared with results obtained from the same subject in vivo. 6 references, 5 figures.

  11. Potential Radon-222 Emissions from the Thorium Nitrate Stockpile

    SciTech Connect

    Terry, J.W.

    2003-09-04

    The Defense National Stockpile Center (DNSC), a field level activity of the Defense Logistics Agency, has stewardship of a stockpile of thorium nitrate that has been in storage for decades. The thorium nitrate stockpile was produced from 1959 to 1964 for the Atomic Energy Commission and previously has been under the control of several federal agencies. The stockpile consists of approximately 7 million pounds of thorium nitrate crystals (hydrate form) stored at two depot locations in the United States (75% by weight at Curtis Bay, Maryland, and 25% by weight at Hammond, Indiana). The material is stored in several configurations in over 21,000 drums. The U.S. Congress has declared the entire DNSC thorium nitrate stockpile to be in excess of the needs of the Department of Defense. Part of DNSC's mission is to safely manage the continued storage, future sales, and/or disposition of the thorium nitrate stockpile. Historically, DNSC has sold surplus thorium nitrate to domestic and foreign companies, but there is no demand currently for this material. Analyses conducted by Oak Ridge National Laboratory (ORNL) in 2001 demonstrated that disposition of the thorium nitrate inventory as a containerized waste, without processing, is the least complex and lowest-cost option for disposition. A characterization study was conducted in 2002 by ORNL, and it was determined that the thorium nitrate stockpile may be disposed of as low-level waste. The Nevada Test Site (NTS) was used as a case study for the disposal alternative, and special radiological analyses and waste acceptance requirements were documented. Among the special radiological considerations is the emission of {sup 220}Rn and {sup 222}Rn from buried material. NTS has a performance objective on the emissions of radon: 20 pCi m{sup -2} sec{sup -1} at the surface of the disposal facility. The radon emissions from the buried thorium nitrate stockpile have been modeled. This paper presents background information and summarizes

  12. Deployment Scenario of Heavy Water Cooled Thorium Breeder Reactor

    SciTech Connect

    Mardiansah, Deby; Takaki, Naoyuki

    2010-06-22

    Deployment scenario of heavy water cooled thorium breeder reactor has been studied. We have assumed to use plutonium and thorium oxide fuel in water cooled reactor to produce {sup 233}U which will be used in thorium breeder reactor. The objective is to analysis the potential of water cooled Th-Pu reactor for replacing all of current LWRs especially in Japan. In this paper, the standard Pressurize Water Reactor (PWR) has been designed to produce 3423 MWt; (i) Th-Pu PWR, (ii) Th-Pu HWR (MFR = 1.0) and (iii) Th-Pu HWR (MFR 1.2). The properties and performance of the core were investigated by using cell and core calculation code. Th-Pu PWR or HWR produces {sup 233}U to introduce thorium breeder reactor. The result showed that to replace all (60 GWe) LWR by thorium breeder reactor within a period of one century, Th-Pu oxide fueled PWR has insufficient capability to produce necessary amount of {sup 233}U and Th-Pu oxide fueled HWR has almost enough potential to produce {sup 233}U but shows positive void reactivity coefficient.

  13. Thorium sorption in seawater suspensions of aluminium oxide particles

    NASA Astrophysics Data System (ADS)

    Niven, Sherry E. H.; Moore, Robert M.

    1993-05-01

    The partitioning of thorium between solid and solution phases in seawater suspensions of aluminium oxide particles was studied in controlled laboratory experiments to determine whether partitioning is consistent with current models of trace-metal adsorption (surface complexation models). Experimental conditions (i.e., thorium and particle concentrations, pH, temperature, salinity) were chosen to be as realistic as possible for coastal seawater while minimizing nonadsorptive processes; 234Th was used as a tracer of thorium, and filtration/ultrafiltration techniques were used to prepare suspensions with minimal colloidal material, as well as to define and to separate solid and solution phases. A comparison of the experimental results with relationships predicted by surface complexation models shows that thorium sorption in the alumina suspensions was consistent with surface complexation theory: Sorption kinetics were consistent with a (pseudo-) first-order reversible reaction at constant particle concentration, the pseudo-first-order forward rate constants had a first-order dependence on particle concentration, and Kd values were independent of particle concentration. Thorium sorption consisted of two distinct reversible reactions, both of which were consistent with surface complexation theory. Second order rate constants were within the range of rate constants reported for the adsorption of divalent metal ions ontoγ-Al 2O 3 surfaces.

  14. 49 CFR 173.434 - Activity-mass relationships for uranium and natural thorium.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ....434 Activity-mass relationships for uranium and natural thorium. The table of activity-mass relationships for uranium and natural thorium are as follows: Thorium and uranium enrichment 1(Wt% 235 U present... 49 Transportation 2 2012-10-01 2012-10-01 false Activity-mass relationships for uranium and...

  15. 49 CFR 173.434 - Activity-mass relationships for uranium and natural thorium.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ....434 Activity-mass relationships for uranium and natural thorium. The table of activity-mass relationships for uranium and natural thorium are as follows: Thorium and uranium enrichment 1(Wt% 235 U present... 49 Transportation 2 2013-10-01 2013-10-01 false Activity-mass relationships for uranium and...

  16. 49 CFR 173.434 - Activity-mass relationships for uranium and natural thorium.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ....434 Activity-mass relationships for uranium and natural thorium. The table of activity-mass relationships for uranium and natural thorium are as follows: Thorium and uranium enrichment 1(Wt% 235 U present... 49 Transportation 2 2014-10-01 2014-10-01 false Activity-mass relationships for uranium and...

  17. 49 CFR 173.426 - Excepted packages for articles containing natural uranium or thorium.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... uranium or thorium. 173.426 Section 173.426 Transportation Other Regulations Relating to Transportation....426 Excepted packages for articles containing natural uranium or thorium. A manufactured article in... or natural thorium, and its packaging, are excepted from the requirements in this subchapter...

  18. 49 CFR 173.426 - Excepted packages for articles containing natural uranium or thorium.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... uranium or thorium. 173.426 Section 173.426 Transportation Other Regulations Relating to Transportation....426 Excepted packages for articles containing natural uranium or thorium. A manufactured article in... or natural thorium, and its packaging, are excepted from the requirements in this subchapter...

  19. 49 CFR 173.426 - Excepted packages for articles containing natural uranium or thorium.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... uranium or thorium. 173.426 Section 173.426 Transportation Other Regulations Relating to Transportation....426 Excepted packages for articles containing natural uranium or thorium. A manufactured article in... or natural thorium, and its packaging, are excepted from the requirements in this subchapter...

  20. Verification study of thorium cross section in MVP calculation of thorium based fuel core using experimental data

    SciTech Connect

    Mai, V. T.; Fujii, T.; Wada, K.; Kitada, T.; Takaki, N.; Yamaguchi, A.; Watanabe, H.; Unesaki, H.

    2012-07-01

    Considering the importance of thorium data and concerning about the accuracy of Th-232 cross section library, a series of experiments of thorium critical core carried out at KUCA facility of Kyoto Univ. Research Reactor Inst. have been analyzed. The core was composed of pure thorium plates and 93% enriched uranium plates, solid polyethylene moderator with hydro to U-235 ratio of 140 and Th-232 to U-235 ratio of 15.2. Calculations of the effective multiplication factor, control rod worth, reactivity worth of Th plates have been conducted by MVP code using JENDL-4.0 library [1]. At the experiment site, after achieving the critical state with 51 fuel rods inserted inside the reactor, the measurements of the reactivity worth of control rod and thorium sample are carried out. By comparing with the experimental data, the calculation overestimates the effective multiplication factor about 0.90%. Reactivity worth of the control rods evaluation using MVP is acceptable with the maximum discrepancy about the statistical error of the measured data. The calculated results agree to the measurement ones within the difference range of 3.1% for the reactivity worth of one Th plate. From this investigation, further experiments and research on Th-232 cross section library need to be conducted to provide more reliable data for thorium based fuel core design and safety calculation. (authors)

  1. Alterations of thorium oxalate morphology by changing elementary precipitation conditions

    NASA Astrophysics Data System (ADS)

    Tyrpekl, V.; Beliš, M.; Wangle, T.; Vleugels, J.; Verwerft, M.

    2017-09-01

    Oxalates of actinide elements are widely used in research and industry mainly due to their low solubility in aqueous solution and easy conversion to oxide. Although thorium oxide is worldwide mostly produced by the oxalate precipitation and conversion route, the powder morphology obtained through this process is known to inhibit the packing and sintering step of the pellet production. The presented work investigates the effects of oxalate precipitation conditions on the final powder morphology. Among the precipitation conditions considered are: pH of the thorium feed solution, concentration, temperature and the order of addition (thorium solution in oxalic acid solution and vice versa) known as reverse/direct strike. Herein, we show that the morphology of the final oxalate depends significantly on the above mentioned precipitation parameters.

  2. Estimating terrestrial uranium and thorium by antineutrino flux measurements

    PubMed Central

    Dye, Stephen T.; Guillian, Eugene H.

    2008-01-01

    Uranium and thorium within the Earth produce a major portion of terrestrial heat along with a measurable flux of electron antineutrinos. These elements are key components in geophysical and geochemical models. Their quantity and distribution drive the dynamics, define the thermal history, and are a consequence of the differentiation of the Earth. Knowledge of uranium and thorium concentrations in geological reservoirs relies largely on geochemical model calculations. This article describes the methods and criteria to experimentally determine average concentrations of uranium and thorium in the continental crust and in the mantle by using site-specific measurements of the terrestrial antineutrino flux. Optimal, model-independent determinations involve significant exposures of antineutrino detectors remote from nuclear reactors at both a midcontinental and a midoceanic site. This would require major, new antineutrino detection projects. The results of such projects could yield a greatly improved understanding of the deep interior of the Earth. PMID:18172211

  3. Thorium Nitrate Stockpile--From Here to Eternity

    SciTech Connect

    Hermes, W. H.; Hylton, T. D.; Mattus, C.H.; Storch, S. N.; Singley, P.S.; Terry. J. W.; Pecullan, M.; Reilly, F. K.

    2003-02-26

    The Defense National Stockpile Center (DNSC), a field level activity of the Defense Logistics Agency (DLA) has stewardship of a stockpile of thorium nitrate that has been in storage for decades. The stockpile is made up of approximately 3.2 million kg (7 million lb) of thorium nitrate crystals (hydrate form) stored at two depot locations in the United States. DNSC sought technical assistance from Oak Ridge National Laboratory (ORNL) to define and quantify the management options for the thorium nitrate stockpile. This paper describes methodologies and results comprising the work in Phase 1 and Phase 2. The results allow the DNSC to structure and schedule needed tasks to ensure continued safe long-term storage and/or phased disposal of the stockpile.

  4. Estimating terrestrial uranium and thorium by antineutrino flux measurements.

    PubMed

    Dye, Stephen T; Guillian, Eugene H

    2008-01-08

    Uranium and thorium within the Earth produce a major portion of terrestrial heat along with a measurable flux of electron antineutrinos. These elements are key components in geophysical and geochemical models. Their quantity and distribution drive the dynamics, define the thermal history, and are a consequence of the differentiation of the Earth. Knowledge of uranium and thorium concentrations in geological reservoirs relies largely on geochemical model calculations. This article describes the methods and criteria to experimentally determine average concentrations of uranium and thorium in the continental crust and in the mantle by using site-specific measurements of the terrestrial antineutrino flux. Optimal, model-independent determinations involve significant exposures of antineutrino detectors remote from nuclear reactors at both a midcontinental and a midoceanic site. This would require major, new antineutrino detection projects. The results of such projects could yield a greatly improved understanding of the deep interior of the Earth.

  5. Atomistic models to investigate thorium dioxide (ThO2).

    PubMed

    Behera, Rakesh K; Deo, Chaitanya S

    2012-05-30

    Thorium dioxide (ThO(2)) is of great interest to energy research as thorium-based nuclear fuel offers the promise of increased proliferation resistance, longer fuel cycles, higher burn-up and improved wasteform characteristics in the generation of nuclear power. However, understanding of ThO(2) as a nuclear fuel is not as comprehensive as UO(2). In order to improve the atomic level understanding of thorium-based fuels, we have developed eight interatomic potential descriptions of ThO(2) by fitting the experimental lattice parameter, elastic constants and static dielectric constants. Using these interatomic potentials, we have calculated the structural and elastic properties, phase stability, defect formation energies, defect binding energies and complexes as well as the energetics of low-index surfaces. A critical assessment of all the potentials is performed by comparing the predicted properties with available experimental and first-principles calculations.

  6. Adsorption of thorium from aqueous solutions by perlite.

    PubMed

    Talip, Z; Eral, M; Hiçsönmez, U

    2009-02-01

    The use of expanded perlite for the adsorption of thorium from aqueous solution by batch technique is presented. The effects of particle size, pH of the solution, initial thorium concentration, shaking time, V/m ratio and temperature were determined. It was found that the adsorption capacity increases by the increase in the pH of the suspensions. The rate of thorium adsorption on expanded perlite was observed to be fast in the first hour of the reaction time. Adsorption isotherms were expressed by Langmuir and Freundlich adsorption models and the adsorption experiments conducted at 30 +/- 1 degrees C showed that the adsorption isotherms correlated well with the Langmuir model. From the adsorption data, thermodynamic parameters such as DeltaG(o), DeltaH(o) and DeltaS(o) were calculated as a function of temperature.

  7. Renouvellement des eaux du fjord du Saguenay

    NASA Astrophysics Data System (ADS)

    Belzile, Melany

    Le fjord du Saguenay, localise dans la region subarctique de l'est du Canada, ala particularite d' etre connecte a un estuaire tres energetique plutot que directement a 1' ocean. L'embouchure du fjord est situee ala rencontre d'un chenal profond et d'un seuil de 20m de profondeur qui limite les echanges d'eau entre le fjord et l'estuaire du Saint-Laurent. Cependant, les grandes amplitudes de maree a son embouchure ont le potentiel d'entrainer des eaux denses du Saint-Laurent a l'interieur du fjord renouvelant ainsi les eaux des differents bassins. Dans le but d' a voir une meilleure comprehension de la dynamique et de la saisonnalite des renouvellements dans le bassin interne, deux mouillages y ont ete deployes pour recolter les premieres donnees de courant, sur toute la colonne d' eau et sur plusieurs mois, ainsi que des observations de temperature et de salinite a differentes profondeurs. L'un de ces mouillages n' a malheureusement pas pu etre analyse en detail dfi a la complexite de ses resultats et au manque de temps. Des profils ont ete recoltes le long de section transversales (transects), couvrant plusieurs saisons et plusieurs annees, ce qui a contribue a une meilleure comprehension de la distribution spatiale des masses d'eau dans le fjord. Les resultats montrent que ladynamique du fjord est plus complexe que ce qui avait ete precedemment presente dans la litterature. Un changement saisonnier abrupte dans la circulation du fjord a ete observe a la rni-fevrier. De plus, des renouvellements non-anticipes juste en-dessous de la thermohalocline (˜ 10 m de profondeur) ont ete observes entre la fin de 1' hiver et le milieu de 1' ete. En fonction des saisons, trois types de renouvellement peuvent etre observes : renouvellements profonds a l'automne et au debut de l'hiver suivis des renouvellements de sous-surface et enfin les renouvellements a des profondeurs intermediaires pendant l'ete. Le changement saisonnier abrupte observe au milieu de l'hiver ainsi que la

  8. Revised Thorium Abundances for Lunar Red Spots

    NASA Technical Reports Server (NTRS)

    Hagerty, J. J.; Lawrence, D. J.; Elphic, R. C.; Feldman, W. C.; Vaniman, D. T.; Hawke, B. R.

    2005-01-01

    Lunar red spots are features on the nearside of the Moon that are characterized by high albedo and by a strong absorption in the ultraviolet. These red spots include the Gruithuisen domes, the Mairan domes, Hansteen Alpha, the southern portion of Montes Riphaeus, Darney Chi and Tau, Helmet, and an area near the Lassell crater. It has been suggested that many of the red spots are extrusive, nonmare, volcanic features that could be composed of an evolved lithlogy enriched in thorium. In fact, Hawke et al. used morphological characteristics to show that Hansteen Alpha is a nonmare volcanic construct. However, because the apparent Th abundances (6 - 7 ppm) were lower than that expected for evolved rock types, Hawke et al. concluded that Hansteen Alpha was composed of an unknown rock type. Subsequent studies by Lawrence et al. used improved knowledge of the Th spatial distribution for small area features on the lunar surface to revisit the interpretation of Th abundances at the Hansteen Alpha red spot. As part of their study, Lawrence et al. used a forward modeling technique to show that the Th abundance at Hansteen Alpha is not 6 ppm, but is more likely closer to 25 ppm, a value consistent with evolved lithologies. This positive correlation between the morphology and composition of Hansteen Alpha provides support for the presence of evolved lithologies on the lunar surface. It is possible, however, that Hansteen Alpha represents an isolated occurrence of non-mare volcanism. That is why we have chosen to use the forward modeling technique of Lawrence et al. to investigate the Th abundances at other lunar red spots, starting with the Gruithuisen domes. Additional information is included in the original extended abstract.

  9. Calculation evaluation of multiplying properties of LWR with thorium fuel

    NASA Astrophysics Data System (ADS)

    Shamanin, I. V.; Grachev, V. M.; Knyshev, V. V.; Bedenko, S. V.; Novikova, N. G.

    2017-01-01

    The results of multiplying properties design research of the unit cell and LWR fuel assembly with the high temperature gas-cooled thorium reactor fuel pellet are presented in the work. The calculation evaluation showed the possibility of using thorium in LWR effectively. In this case the amount of fissile isotope is 2.45 times smaller in comparison with the standard loading of LWR. The research and numerical experiments were carried out using the verified accounting code of the program MCU5, modern libraries of evaluated nuclear data and multigroup approximations.

  10. Separation of thorium and uranium in nitric acid solution using silica based anion exchange resin.

    PubMed

    Chen, Yanliang; Wei, Yuezhou; He, Linfeng; Tang, Fangdong

    2016-09-30

    To separate thorium and uranium in nitric acid solution using anion exchange process, a strong base silica-based anion exchange resin (SiPyR-N4) was synthesized. Batch experiments were conducted and the separation factor of thorium and uranium in 9M nitric acid was about 10. Ion exchange chromatography was applied to separate thorium and uranium in different ratios. Uranium could be eluted by 9M nitric acid and thorium was eluted by 0.1M nitric acid. It was proved that thorium and uranium can be separated and recovered successfully by this method. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Variation of stability constants of thorium citrate complexes and of thorium hydrolysis constants with ionic strength

    SciTech Connect

    Choppin, G.R.; Erten, H.N.; Xia, Y.X.

    1995-09-01

    Citrate is among the organic anions that are expected to be present in the wastes planned for deposition in the Waste Isolation Pilot Plant repository. In this study, a solvent extraction method has been used to measure the stability constants of Thorium(IV)[Th(IV)] with citrate anions in aqueous solutions with (a) NaClO{sub 4} and (b) NaCl as the background electrolytes. The ionic strengths were varied up to 5 m (NaCl) and 14 m (NaClO{sub 4}). The data from the NaClO{sub 4} solutions at varying pH values were used to calculate the hydrolysis constants for formation of Th(OH){sup 3+} at the different ionic strengths.

  12. Selective Precipitation of Thorium lodate from a Tartaric Acid-Hydrogen Peroxide Medium Application to Rapid Spectrophotometric Determination of Thorium in Silicate Rocks and in Ores

    USGS Publications Warehouse

    Grimaldi, F.S.

    1957-01-01

    This paper presents a selective iodate separation of thorium from nitric acid medium containing d-tartaric acid and hydrogen peroxide. The catalytic decomposition of hydrogen peroxide is prevented by the use of 8quinolinol. A few micrograms of thorium are separated sufficiently clean from 30 mg. of such oxides as cerium, zirconium, titanium, niobium, tantalum, scandium, or iron with one iodate precipitation to allow an accurate determination of thorium with the thoronmesotartaric acid spectrophotometric method. The method is successful for the determination of 0.001% or more of thorium dioxide in silicate rocks and for 0.01% or more in black sand, monazite, thorite, thorianite, eschynite, euxenite, and zircon.

  13. "Cirque du Freak."

    ERIC Educational Resources Information Center

    Rivett, Miriam

    2002-01-01

    Considers the marketing strategies that underpin the success of the "Cirque du Freak" series. Describes how "Cirque du Freak" is an account of events in the life of schoolboy Darren Shan. Notes that it is another reworking of the vampire narrative, a sub-genre of horror writing that has proved highly popular with both adult and…

  14. "Cirque du Freak."

    ERIC Educational Resources Information Center

    Rivett, Miriam

    2002-01-01

    Considers the marketing strategies that underpin the success of the "Cirque du Freak" series. Describes how "Cirque du Freak" is an account of events in the life of schoolboy Darren Shan. Notes that it is another reworking of the vampire narrative, a sub-genre of horror writing that has proved highly popular with both adult and…

  15. Analytical Characterization of the Thorium Nitrate Stockpile

    SciTech Connect

    Mattus, CH

    2003-12-30

    For several years, Oak Ridge National Laboratory (ORNL) has been supporting the Defense Logistics Agency-Defense National Stockpile Center with stewardship of a thorium nitrate (ThN) stockpile. The effort for fiscal year 2002 was to prepare a sampling and analysis plan and to use the activities developed in the plan to characterize the ThN stockpile. The sampling was performed in June and July 2002 by RWE NUKEM with oversight by ORNL personnel. The analysis was performed by Southwest Research Institute of San Antonio, Texas, and data validation was performed by NFT, Inc., of Oak Ridge, Tennessee. Of the {approx} 21,000 drums in the stockpile, 99 were sampled and 53 were analyzed for total metals composition, radiological constituents (using alpha and gamma spectrometry), and oxidizing characteristics. Each lot at the Curtis Bay Depot was sampled. Several of the samples were also analyzed for density. The average density of the domestic ThN was found to be 1.89 {+-} 0.08 g/cm{sup 3}. The oxidizer test was performed following procedures issued by the United Nations in 1999. Test results indicated that none of the samples tested was a Division 5.1 oxidizer per Department of Transportation definition. The samples were analyzed for total metals following the U.S. Environmental Protection Agency methods SW-846-6010B and 6020 (EPA 2003) using a combination of inductively coupled plasma--atomic emission spectroscopy and inductively coupled plasma--mass spectroscopy techniques. The results were used to compare the composition of the eight Resource Conservation and Recovery Act metals present in the sample (arsenic, barium, cadmium, chromium, lead, mercury, selenium, and silver) to regulatory limits. None of the samples was found to be hazardous for toxicity characteristics. The radiological analyses confirmed, when possible, the results obtained by the inductively coupled plasma analyses. These results--combined with the historical process knowledge acquired on the material

  16. Map of Martian Thorium at Mid-Latitudes

    NASA Technical Reports Server (NTRS)

    2003-01-01

    This gamma ray spectrometer map of the mid-latitude region of Mars is based on gamma-rays from the element thorium. Thorium is a naturally radioactive element that exists in rocks and soils in extremely small amounts. The region of highest thorium content, shown in red, is found in the northern part of Acidalia Planitia (50 degrees latitude, -30 degrees longitude). Areas of low thorium content, shown in blue, are spread widely across the planet with significant low abundances located to the north of Olympus Mons (near 55 degrees latitude, -155 degrees longitude), to the east of the Tharsis volcanoes (-10 degrees latitude, -80 degrees longitude) and to the south and east of Elysium Mons (20 degrees latitude, 160 degrees longitude). Contours of constant surface elevation are also shown. The long continuous contour line running from east to west marks the approximate separation of the younger lowlands in the north from the older highlands in the south.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The gamma ray spectrometer was provided by the University of Arizona, Tucson. Lockheed Martin Astronautics, Denver, Colo., is the prime contractor for the project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  17. Helium on Venus - Implications for uranium and thorium

    NASA Technical Reports Server (NTRS)

    Prather, M. J.; Mcelroy, M. B.

    1983-01-01

    Helium is removed at an average rate of 10 to the 6th atoms per square centimeter per second from Venus's atmosphere by the solar wind following ionization above the plasmapause. The surface source of helium-4 on Venus is similar to that on earth, suggesting comparable abundances of crustal uranium and thorium.

  18. Design study of long-life PWR using thorium cycle

    SciTech Connect

    Subkhi, Moh. Nurul; Su'ud, Zaki; Waris, Abdul

    2012-06-06

    Design study of long-life Pressurized Water Reactor (PWR) using thorium cycle has been performed. Thorium cycle in general has higher conversion ratio in the thermal spectrum domain than uranium cycle. Cell calculation, Burn-up and multigroup diffusion calculation was performed by PIJ-CITATION-SRAC code using libraries based on JENDL 3.2. The neutronic analysis result of infinite cell calculation shows that {sup 231}Pa better than {sup 237}Np as burnable poisons in thorium fuel system. Thorium oxide system with 8%{sup 233}U enrichment and 7.6{approx} 8%{sup 231}Pa is the most suitable fuel for small-long life PWR core because it gives reactivity swing less than 1%{Delta}k/k and longer burn up period (more than 20 year). By using this result, small long-life PWR core can be designed for long time operation with reduced excess reactivity as low as 0.53%{Delta}k/k and reduced power peaking during its operation.

  19. Discovery of actinium, thorium, protactinium, and uranium isotopes

    NASA Astrophysics Data System (ADS)

    Fry, C.; Thoennessen, M.

    2013-05-01

    Thirty-one actinium, thirty-one thorium, twenty-eight protactinium, and twenty-three uranium isotopes have so far been observed; the discovery of these isotopes is described. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

  20. Map of Martian Thorium at Mid-Latitudes

    NASA Image and Video Library

    2003-03-13

    This gamma ray spectrometer map of the mid-latitude region of Mars is based on gamma-rays from the element thorium. Thorium is a naturally radioactive element that exists in rocks and soils in extremely small amounts. The region of highest thorium content, shown in red, is found in the northern part of Acidalia Planitia (50 degrees latitude, -30 degrees longitude). Areas of low thorium content, shown in blue, are spread widely across the planet with significant low abundances located to the north of Olympus Mons (near 55 degrees latitude, -155 degrees longitude), to the east of the Tharsis volcanoes (-10 degrees latitude, -80 degrees longitude) and to the south and east of Elysium Mons (20 degrees latitude, 160 degrees longitude). Contours of constant surface elevation are also shown. The long continuous contour line running from east to west marks the approximate separation of the younger lowlands in the north from the older highlands in the south. http://photojournal.jpl.nasa.gov/catalog/PIA04257

  1. Thermodynamic properties and structural stability of thorium dioxide.

    PubMed

    Lu, Y; Yang, Y; Zhang, P

    2012-06-06

    Using density functional theory (DFT) calculations, we have systematically investigated the thermodynamic properties and structural stabilities of thorium dioxide (ThO(2)). Based on the calculated phonon dispersion curves, we have calculated the thermal expansion coefficient, bulk modulus, and heat capacities at different temperatures for ThO(2) under the quasi-harmonic approximation. All the results are in good agreement with corresponding experiments proving the validity of our methods. Our theoretical studies can aid a clearer understanding of the thermodynamic behaviors of ThO(2) at different temperatures. In addition, we have also studied possible defect formations and diffusion behaviors of helium in ThO(2), to discuss its structural stability. It is found that in intrinsic ThO(2) without any Fermi energy shifts, the interstitial Th(i)(4+) defect rather than oxygen or thorium vacancies, interstitial oxygen, or any kinds of Frenkel pairs, is the most probable to form with an energy release of 1.74 eV. However, after upshifting the Fermi energy, the formation of the other defects also becomes possible. Regarding helium diffusion, we find that only through the thorium vacancy can it occur with the small energy barrier of 0.52 eV. Otherwise, helium atoms can hardly incorporate or diffuse in ThO(2). Our results indicate that upward shifting of the Fermi energy of ThO(2) should be prevented to avoid the formation of thorium vacancies so as to avert helium caused damage.

  2. 229Thorium-doped calcium fluoride for nuclear laser spectroscopy.

    PubMed

    Dessovic, P; Mohn, P; Jackson, R A; Winkler, G; Schreitl, M; Kazakov, G; Schumm, T

    2014-03-12

    The (229)thorium isotope presents an extremely low-energy isomer state of the nucleus which is expected around 7.8 eV, in the vacuum ultraviolet (VUV) regime. This unique system may bridge between atomic and nuclear physics, enabling coherent manipulation and precision spectroscopy of nuclear quantum states using laser light. It has been proposed to implant (229)thorium into VUV transparent crystal matrices to facilitate laser spectroscopy and possibly realize a solid-state nuclear clock. In this work, we validate the feasibility of this approach by computer modelling of thorium doping into calcium fluoride single crystals. Using atomistic modelling and full electronic structure calculations, we find a persistent large band gap and no additional electronic levels emerging in the middle of the gap due to the presence of the dopant, which should allow direct optical interrogation of the nuclear transition.Based on the electronic structure, we estimate the thorium nuclear quantum levels within the solid-state environment. Precision laser spectroscopy of these levels will allow the study of a broad range of crystal field effects, transferring Mössbauer spectroscopy into the optical regime.

  3. Helium on Venus - Implications for uranium and thorium

    NASA Technical Reports Server (NTRS)

    Prather, M. J.; Mcelroy, M. B.

    1983-01-01

    Helium is removed at an average rate of 10 to the 6th atoms per square centimeter per second from Venus's atmosphere by the solar wind following ionization above the plasmapause. The surface source of helium-4 on Venus is similar to that on earth, suggesting comparable abundances of crustal uranium and thorium.

  4. Thorium resonance ionization mass spectrometry for geochronological and geochemical applications

    SciTech Connect

    Fearey, B.L.; Johnson, S.G.; Nogar, N.; Murrell, M.T.; Miller, C.M.

    1990-01-01

    Resonance Ionization Mass Spectrometry (RIMS) is being developed to measure thorium isotopics from geological samples. These measurements, in conjunction with uranium measurements by thermal ionization, permit geochronological dating in the timescale of 10,000 to 350,000 years. 15 refs., 2 figs.

  5. Map of Martian Thorium at Mid-Latitudes

    NASA Technical Reports Server (NTRS)

    2003-01-01

    This gamma ray spectrometer map of the mid-latitude region of Mars is based on gamma-rays from the element thorium. Thorium is a naturally radioactive element that exists in rocks and soils in extremely small amounts. The region of highest thorium content, shown in red, is found in the northern part of Acidalia Planitia (50 degrees latitude, -30 degrees longitude). Areas of low thorium content, shown in blue, are spread widely across the planet with significant low abundances located to the north of Olympus Mons (near 55 degrees latitude, -155 degrees longitude), to the east of the Tharsis volcanoes (-10 degrees latitude, -80 degrees longitude) and to the south and east of Elysium Mons (20 degrees latitude, 160 degrees longitude). Contours of constant surface elevation are also shown. The long continuous contour line running from east to west marks the approximate separation of the younger lowlands in the north from the older highlands in the south.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The gamma ray spectrometer was provided by the University of Arizona, Tucson. Lockheed Martin Astronautics, Denver, Colo., is the prime contractor for the project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  6. Uranium- and thorium-bearing pegmatites of the United States

    SciTech Connect

    Adams, J.W.; Arengi, J.T.; Parrish, I.S.

    1980-04-01

    This report is part of the National Uranium Resource Evaluation (NURE) Program designed to identify criteria favorable for the occurrence of the world's significant uranium deposits. This project deals specifically with uranium- and thorium-bearing pegmatites in the United States and, in particular, their distribution and origin. From an extensive literature survey and field examination of 44 pegmatite localities in the United States and Canada, the authors have compiled an index to about 300 uranium- and thorium-bearing pegmatites in the United States, maps giving location of these deposits, and an annotated bibliography to some of the most pertinent literature on the geology of pegmatites. Pegmatites form from late-state magma differentiates rich in volatile constituents with an attendant aqueous vapor phase. It is the presence of an aqueous phase which results in the development of the variable grain size which characterizes pegmatites. All pegmatites occur in areas of tectonic mobility involving crustal material usually along plate margins. Those pegmatites containing radioactive mineral species show, essentially, a similar distribution to those without radioactive minerals. Criteria such as tectonic setting, magma composition, host rock, and elemental indicators among others, all serve to help delineate areas more favorable for uranium- and thorium-bearing pegmatites. The most useful guide remains the radioactivity exhibited by uranium- and thorium-bearing pegmatites. Although pegmatites are frequently noted as favorable hosts for radioactive minerals, the general paucity and sporadic distribution of these minerals and inherent mining and milling difficulties negate the resource potential of pegmatites for uranium and thorium.

  7. LWR First Recycle of TRU with Thorium Oxide for Transmutation and Cross Sections

    SciTech Connect

    Andrea Alfonsi; Gilles Youinou

    2012-07-01

    Thorium has been considered as an option to uranium-based fuel, based on considerations of resource utilization (thorium is approximately three times more plentiful than uranium) and as a result of concerns about proliferation and waste management (e.g. reduced production of plutonium, etc.). Since the average composition of natural Thorium is dominated (100%) by the fertile isotope Th-232, Thorium is only useful as a resource for breeding new fissile materials, in this case U-233. Consequently a certain amount of fissile material must be present at the start-up of the reactor in order to guarantee its operation. The thorium fuel can be used in both once-through and recycle options, and in both fast and thermal spectrum systems. The present study has been aimed by the necessity of investigating the option of using reprocessed plutonium/TRU, from a once-through reference LEU scenario (50 GWd/ tIHM), mixed with natural thorium and the need of collect data (mass fractions, cross-sections etc.) for this particular fuel cycle scenario. As previously pointed out, the fissile plutonium is needed to guarantee the operation of the reactor. Four different scenarios have been considered: • Thorium – recycled Plutonium; • Thorium – recycled Plutonium/Neptunium; • Thorium – recycled Plutonium/Neptunium/Americium; • Thorium – recycled Transuranic. The calculations have been performed with SCALE6.1-TRITON.

  8. LWR First Recycle of TRU with Thorium Oxide for Transmutation and Cross Sections

    SciTech Connect

    Andrea Alfonsi; Gilles Youinou; Sonat Sen

    2013-02-01

    Thorium has been considered as an option to uranium-based fuel, based on considerations of resource utilization (thorium is approximately three times more plentiful than uranium) and as a result of concerns about proliferation and waste management (e.g. reduced production of plutonium, etc.). Since the average composition of natural Thorium is dominated (100%) by the fertile isotope Th-232, Thorium is only useful as a resource for breeding new fissile materials, in this case U-233. Consequently a certain amount of fissile material must be present at the start-up of the reactor in order to guarantee its operation. The thorium fuel can be used in both once-through and recycle options, and in both fast and thermal spectrum systems. The present study has been aimed by the necessity of investigating the option of using reprocessed plutonium/TRU, from a once-through reference LEU scenario (50 GWd/ tIHM), mixed with natural thorium and the need of collect data (mass fractions, cross-sections etc.) for this particular fuel cycle scenario. As previously pointed out, the fissile plutonium is needed to guarantee the operation of the reactor. Four different scenarios have been considered: • Thorium – recycled Plutonium; • Thorium – recycled Plutonium/Neptunium; • Thorium – recycled Plutonium/Neptunium/Americium; • Thorium – recycled Transuranic. The calculations have been performed with SCALE6.1-TRITON.

  9. Current research activity in the measurement of thorium and the identification of future research needs.

    PubMed

    White, M A; Howe, A M; Rosen, P; Holmes, L

    2001-01-01

    A pre-requisite in the setting and enforcement of regulatory limits for exposure to thorium in the workplace is that thorium and its progeny can be accurately measured. Literature surveys have shown that the majority of thorium measurements were performed using either a radiochemical technique, such as alpha or gamma spectroscopy, or ICP-MS. For many methods. there was a separation step to isolate and pre-concentrate thorium from the sample matrix. Thorium was most commonly measured in geological matrices and industrial materials. A survey of current research activity was performed through distribution of a questionnaire to laboratories and national centres. From the rcsponses, four areas of current activity were identified: (i) development of methods for low level thorium determination, (ii) biological monitoring and metabolism of thorium, (iii) environmental monitoring for thorium, and (iv) health risks from X ray contract media. Two key areas for priority research were identified by the thorium Thematic Network: namely sample preparation methods and for traceable standards and reference materials for thorium analysis.

  10. Influence of plant activity and phosphates on thorium bioavailability in soils from Baotou area, Inner Mongolia.

    PubMed

    Guo, Pengran; Jia, Xiaoyu; Duan, Taicheng; Xu, Jingwei; Chen, Hangting

    2010-09-01

    Harm of thorium to living organisms is governed by its bioavailability. Thorium bioavailability in the soil-plant system of Baotou rare earth industrial area was studied using pot experiments of wheat and single extraction methods. The effects of wheat growth stage and phosphate on thorium bioavailability were also investigated. Based on extractabilities of various extraction methods (CaCl(2), NH(4)NO(3), EDTA, HOAc) and correlation analysis of thorium uptake by wheat plant and extractable thorium, a mixture of 0.02M EDTA+0.5M NH(4)OAc (pH 4.6) was found suitable for evaluation of thorium bioavailability in Baotou soil, which could be predicted quantitatively by multiple regression models. Because of differences of wheat root activities, thorium bioavailability in rhizosphere soil was higher than in bulk soil at tillering stage, but the reverse occurred at jointing stage. Phosphate addition induced the mineralization of soluble thorium by forming stable thorium phosphate compounds, and reduced thorium bioavailability in soil.

  11. La naissance du parsec

    NASA Astrophysics Data System (ADS)

    Arenou, F.

    2010-01-01

    Les définitions du parsec et de la magnitude absolue sont le fruit de compromis pour régler trois problèmes entremêlés au début du XXème siècle: quelle unité de distance stellaire adopter? Quel nom lui donner? Comment comparer les luminosités intrinsèques des différentes étoiles?

  12. Production of Actinium-225 via High Energy Proton Induced Spallation of Thorium-232

    SciTech Connect

    Harvey, James T.; Nolen, Jerry; Vandergrift, George; Gomes, Itacil; Kroc, Tom; Horwitz, Phil; McAlister, Dan; Bowers, Del; Sullivan, Vivian; Greene, John

    2011-12-30

    The science of cancer research is currently expanding its use of alpha particle emitting radioisotopes. Coupled with the discovery and proliferation of molecular species that seek out and attach to tumors, new therapy and diagnostics are being developed to enhance the treatment of cancer and other diseases. This latest technology is commonly referred to as Alpha Immunotherapy (AIT). Actinium-225/Bismuth-213 is a parent/daughter alpha-emitting radioisotope pair that is highly sought after because of the potential for treating numerous diseases and its ability to be chemically compatible with many known and widely used carrier molecules (such as monoclonal antibodies and proteins/peptides). Unfortunately, the worldwide supply of actinium-225 is limited to about 1,000mCi annually and most of that is currently spoken for, thus limiting the ability of this radioisotope pair to enter into research and subsequently clinical trials. The route proposed herein utilizes high energy protons to produce actinium-225 via spallation of a thorium-232 target. As part of previous R and D efforts carried out at Argonne National Laboratory recently in support of the proposed US FRIB facility, it was shown that a very effective production mechanism for actinium-225 is spallation of thorium-232 by high energy proton beams. The base-line simulation for the production rate of actinium-225 by this reaction mechanism is 8E12 atoms per second at 200 MeV proton beam energy with 50 g/cm2 thorium target and 100 kW beam power. An irradiation of one actinium-225 half-life (10 days) produces {approx}100 Ci of actinium-225. For a given beam current the reaction cross section increases slightly with energy to about 400 MeV and then decreases slightly for beam energies in the several GeV regime. The object of this effort is to refine the simulations at proton beam energies of 400 MeV and above up to about 8 GeV. Once completed, the simulations will be experimentally verified using 400 MeV and 8 Ge

  13. SELECTIVE SEPARATION OF URANIUM FROM THORIUM, PROTACTINIUM AND FISSION PRODUCTS BY PEROXIDE DISSOLUTION METHOD

    DOEpatents

    Seaborg, G.T.; Gofman, J.W.; Stoughton, R.W.

    1959-08-18

    A method is described for separating U/sup 233/ from thorium and fission products. The separation is effected by forming a thorium-nitric acid solution of about 3 pH, adding hydrogen peroxide to precipitate uranium and thorium peroxide, treating the peroxides with sodium hydroxide to selectively precipitate the uranium peroxide, and reacting the separated solution with nitric acid to re- precipitate the uranium peroxide.

  14. Determination of thorium in the parts per million range in rocks

    USGS Publications Warehouse

    Levine, H.; Grimaldi, F.S.

    1958-01-01

    A procedure is presented for the determination of thorium in the concentration range of 0??2 to 10 parts per million ThO2 in felsic or mafic rocks. Thorium is extracted by mesityl oxide and purified by iodate precipitation from nitric acid medium containing tartaric acid and hydrogen peroxide. The thorium is determined spectrophotometrically with thoron from meso-tartaric acid medium. ?? 1958.

  15. Landscape control of uranium and thorium in boreal streams - spatiotemporal variability and the role of wetlands

    NASA Astrophysics Data System (ADS)

    Lidman, F.; Mörth, C. M.; Laudon, H.

    2012-11-01

    The concentrations of uranium and thorium in ten partly nested streams in the boreal forest region were monitored over a two-year period. The investigated catchments ranged from small headwaters (0.1 km2) up to a fourth-order stream (67 km2). Considerable spatiotemporal variations were observed, with little or no correlation between streams. The fluxes of both uranium and thorium varied substantially between the subcatchments, ranging from 1.7 to 30 g km-2 a-1 for uranium and from 3.2 to 24 g km-2 a-1 for thorium. Airborne gamma spectrometry was used to measure the concentrations of uranium and thorium in surface soils throughout the catchment, suggesting that the concentrations of uranium and thorium in mineral soils are similar throughout the catchment. The fluxes of uranium and thorium were compared to a wide range of parameters characterising the investigated catchments and the chemistry of the stream water, e.g. soil concentrations of these elements, pH, TOC (total organic carbon), Al, Si and hydrogen carbonate, but it was concluded that the spatial variabilities in the fluxes of both uranium and thorium mainly were controlled by wetlands. The results indicate that there is a predictable and systematic accumulation of both uranium and thorium in boreal wetlands that is large enough to control the transport of these elements. On the landscape scale approximately 65-80% of uranium and 55-65% of thorium entering a wetland were estimated to be retained in the peat. Overall, accumulation in mires and other types of wetlands was estimated to decrease the fluxes of uranium and thorium from the boreal forest landscape by 30-40%, indicating that wetlands play an important role for the biogeochemical cycling of uranium and thorium in the boreal forest landscape. The atmospheric deposition of uranium and thorium was also quantified, and its contribution to boreal streams was found to be low compared to weathering.

  16. Thorium X treatment: multiple basal cell carcinomas within a port-wine stain.

    PubMed

    Natkunarajah, J; Cliff, S

    2009-07-01

    Thorium X is an ionizing radiation treatment that was commonly used by dermatologists in the 1930 s to 1950 s to treat a variety of benign dermatoses and vascular lesions including port-wine stains. By the 1960 s, thorium X was discontinued due to poor clinical results and the carcinogenic potential. We report a 64-year-old man with a history of multiple basal cell carcinomas in a facial port wine stain, which had previously been treated with thorium X.

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

    SciTech Connect

    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.

  18. An efficient chelator for complexation of thorium-227.

    PubMed

    Ramdahl, Thomas; Bonge-Hansen, Hanne T; Ryan, Olav B; Larsen, Smund; Herstad, Gunnar; Sandberg, Marcel; Bjerke, Roger M; Grant, Derek; Brevik, Ellen M; Cuthbertson, Alan S

    2016-09-01

    We present the synthesis and characterization of a highly efficient thorium chelator, derived from the octadentate hydroxypyridinone class of compounds. The chelator forms extremely stable complexes with fast formation rates in the presence of Th-227 (ambient temperature, 20min). In addition, mouse biodistribution data are provided which indicate rapid hepatobiliary excretion route of the chelator which, together with low bone uptake, supports the stability of the complex in vivo. The carboxylic acid group may be readily activated for conjugation through the ɛ-amino groups of lysine residues in biomolecules such as antibodies. This chelator is a critical component of a new class of Targeted Thorium Conjugates (TTCs) currently under development in the field of oncology. Copyright © 2016. Published by Elsevier Ltd.

  19. Coprecipitation of thorium and uranium peroxides from acid solutions

    SciTech Connect

    McTaggart, D.R.; Mailen, J.C.

    1981-01-01

    The factors affecting successful coprecipitation of thorium and uranium peroxides from acid media were studied. Variables considered in this work were H/sup +/ concentration, H/sub 2/O/sub 2/ concentration, duration of contact, and rate of feed solution addition. In all experiments, stock solutions of Th(NO/sub 3/)/sub 4/ and UO/sub 2/(NO/sub 3/)/sub 2/ were fed at a controlled rate into H/sub 2/O/sub 2/ solutions with constant stirring. Samples were taken as a function of time to follow the H/sup +/ concentration of the solution, uranium precipitation, thorium precipitation, precipitant weight/volume of solution, and crystalline structure and growth. The optimum conditions for maximum coprecipitation are low H/sup +/ concentration, high H/sub 2/O/sub 2/ concentration, and extended contact time between the solutions.

  20. Welding and Weldability of Thorium-Doped Iridium Alloys

    SciTech Connect

    David, S.A.; Ohriner, E.K.; King, J.F.

    2000-03-12

    Ir-0.3%W alloys doped with thorium are currently used as post-impact containment material for radioactive fuel in thermoelectric generators that provide stable electrical power for a variety of outer planetary space exploration missions. Welding and weldability of a series of alloys was investigated using arc and laser welding processes. Some of these alloys are prone to severe hot-cracking during welding. Weldability of these alloys was characterized using Sigmajig weldability test. Hot-cracking is influenced to a great extent by the fusion zone microstructure and composition. Thorium content and welding atmosphere were found to be very critical. The weld cracking behavior in these alloys can be controlled by modifying the fusion zone microstructure. Fusion zone microstructure was found to be controlled by welding process, process parameters, and the weld pool shape.

  1. PREPARATION OF HIGH-DENSITY THORIUM OXIDE SPHERES

    DOEpatents

    McNees, R.A. Jr.; Taylor, A.J.

    1963-12-31

    A method of preparing high-density thorium oxide spheres for use in pellet beds in nuclear reactors is presented. Sinterable thorium oxide is first converted to free-flowing granules by means such as compression into a compact and comminution of the compact. The granules are then compressed into cubes having a density of 5.0 to 5.3 grams per cubic centimeter. The cubes are tumbled to form spheres by attrition, and the spheres are then fired at 1250 to 1350 deg C. The fired spheres are then polished and fired at a temperature above 1650 deg C to obtain high density. Spherical pellets produced by this method are highly resistant to mechanical attrition hy water. (AEC)

  2. Methane to methanol conversion induced by thorium oxide through the CH3Th(O)H intermediate in solid argon.

    PubMed

    Gong, Yu; Andrews, Lester; Jackson, Virgil E; Dixon, David A

    2012-10-15

    Reactions of ThO molecules and CH(4) have been investigated in solid argon near 4 K. The CH(3)Th(O)H molecule is produced when the sample is exposed to UV irradiation. Identification of this new intermediate is substantiated by observation of the Th═O and Th-H stretching vibrational modes with isotopic substitution via matrix infrared spectroscopy, and the assignments are supported by electronic structure frequency calculations. Methanol absorptions increase together with formation of the CH(3)Th(O)H molecule, suggesting a methane to methanol conversion induced by thorium oxide proceeding through the CH(3)Th(O)H intermediate. The formation of CH(3)Th(O)H from ThO + CH(4) is exothermic (ΔH(rxn) = -11 kcal/mol) with an energy barrier of 30 kcal/mol at the CCSD(T)//B3LYP level. Decomposition of this intermediate to form methanol involves spin crossing, and the overall reaction from the intermediate is endothermic by 127 kcal/mol. There is no activation energy for the reaction of thorium atoms with methanol to give CH(3)Th(O)H, as observed in separate experiments with Th and CH(3)OH.

  3. Thorium and uranium diphosphonates: Syntheses, structures, and spectroscopic properties

    SciTech Connect

    Adelani, Pius O.; Albrecht-Schmitt, Thomas E.

    2012-08-15

    Four new thorium and uranium diphosphonate compounds, [H{sub 3}O]{l_brace}Th{sub 2}[C{sub 6}H{sub 4}(PO{sub 3}){sub 2}]{sub 2}F{r_brace} (Thbbp-1), An{sub 2}{l_brace}(O{sub 3}PC{sub 6}H{sub 4}PO{sub 3}H){sub 2}[C{sub 6}H{sub 4}(PO{sub 3}H){sub 2}]{r_brace} [An=Th(IV), U(IV)] (Thbbp-2)/(U4bbp), and [(C{sub 2}H{sub 5})(CH{sub 3}){sub 3}N][(UO{sub 2}){sub 3}(O{sub 3}PC{sub 6}H{sub 4}PO{sub 3}H){sub 2}F(H{sub 2}O)] (U6bbp) have been synthesized hydrothermally using 1,4-benzenebisphosphonic acid as ligand. The crystal structures of these compounds were determined by single crystal X-ray diffraction. Thbbp-1 and Thbbp-2 contain seven-coordinate Th(IV) within ThO{sub 6}F and ThO{sub 7} units with capped trigonal prismatic and capped octahedral geometries, respectively. U4bbp is isotypic with Thbbp-2. The structure of U6bbp contains U(VI) is the common seven-coordinate pentagonal bipyramid. - Graphical abstract: Coordination polyhedra and luminescence properties in thorium and uranium compounds. Highlights: Black-Right-Pointing-Pointer Three-dimensional thorium and uranium complexes. Black-Right-Pointing-Pointer Conversion of U(VI) to U(IV) under hydrothermal condition. Black-Right-Pointing-Pointer Unusual seven-coordinate thorium complexes exhibiting capped octahedral and capped trigonal prismatic geometries.

  4. Thorium-free interference coatings for infrared applications

    NASA Astrophysics Data System (ADS)

    Laux, Sven; Bernitzki, Helmut; Fasold, Dieter; Gittler, Elvira; Schmidt, Frank; Weyh, Thomas; Wurlitzer, Gottfried

    2005-09-01

    This paper discusses improvements in manufacturing of coated infrared optical components. Such components often have key functions in defence, security or space applications and must withstand severe environmental conditions. Therefore, very durable coatings are desired. As a consequence of its radioactivity the formerly used low refractive index material thorium fluoride is substituted. Examples for beam splitter cubes contacted with novel infrared transparent cement, interference filters, mirrors and AR coatings are presented.

  5. Health effects of a thorium waste disposal site.

    PubMed Central

    Najem, G R; Voyce, L K

    1990-01-01

    A case-control study of 112 households residing in the vicinity of a thorium waste disposal site found a higher prevalence of birth defects (RR 2.1) and liver diseases (RR 2.3) among exposed than the unexposed group. The numbers were quite small and the confidence intervals wide, however, so that no definite conclusions can be drawn from these data. PMID:2316775

  6. Speciation of thorium in phosphate-containing solutions

    NASA Astrophysics Data System (ADS)

    Fourest, B.; Baglan, N.; Guillaumont, R.; Blain, G.; Legoux, Y.

    1994-10-01

    The equilibrium between thorium orthophosphate (Th3(PO4)4), labelled with the radioactive thorium isotope Th-277, and phosphate-containing solutions has been investigated as a function of pH and total concentration of phosphate groups (5 less than (pH) less than 9; 0 less than C(sub PO4) less than 1.5 mol/l). Since Th3(PO4)4 is a very insoluble compound, even in relatively concentrated phosphoric media, Th-277 has been detected in solutions near neutrality only for c(sub PO4) greater than 0.1 mol/l. Under these conditions, the thorium concentration has been measured after ultrafiltration (cutting size of the species at 5 nm) by gamma-ray spectroscopy in the range 10(exp -9)-10(exp -5) mol/l. The solubility curves, c(sub Th) vs. pH value at constant c(sub PO4) and O2 vs.c(sub PO4) at constant pH, lead to the determination of the prevailing species in the solutions: at a pH of 6-7, (ThO(HPO4)3(H2PO4))(5-) and (ThO(HPO4)3(H2PO4)2)(6-) are the presumed complex forms of thorium for 0.3 less than c(sub PO4) less than 0.8 mol/l and 0.8 less than c(sub PO4) less than 1.5 mol/l respectively.

  7. Characterization of thorium and uranium contaminated soil from a nuclear fuel facility

    SciTech Connect

    Brown, N.R.; Buck, E.C.; Dietz, N.L.; Bates, J.K.; Carlson, B.

    1994-02-01

    This paper describes the utility of soil characterization using electron microscopy to support decontamination efforts of contaminated soil. Soil contaminated with thorium and uranium from the grounds of a nuclear fuel manufacturing facility was subjected to remediation efforts. A light acid leach was able to remove only 30% of the thorium suggesting that the thorium was present in two or more forms. Analytical electron microscopy determined that all of the thorium was present as ThO{sub 2}, but in a bimodal size distribution and occasionally closely associated with other minerals. Electron microscopy was useful in understanding the remediation data and demonstrates the need for characterization of contaminated soils.

  8. Landscape control of uranium and thorium in boreal streams - spatiotemporal variability and the role of wetlands

    NASA Astrophysics Data System (ADS)

    Lidman, F.; Mörth, C. M.; Laudon, H.

    2012-03-01

    The concentrations of uranium and thorium in ten partly nested streams in the boreal forest region were monitored over a two-year period. Considerable spatiotemporal variations were observed, with little or no correlation between streams. The export of both uranium and thorium varied substantially between the subcatchments, ranging from 1.7 to 30 g km-2 a-1 for uranium and from 3.2 to 24 g km-2 a-1 for thorium. Airborne gamma spectrometry was used to measure the concentrations of uranium and thorium in surface soils throughout the catchment, but could not explain the variability in the export. Instead, the extent of lakes and mires within each subcatchment was found to be a stronger predictor for the transport of uranium and thorium. The results indicate that there is a predictable and systematic accumulation of both uranium and thorium in boreal mires. Approximately 65-80 % of uranium and 55-65 % of thorium entering a mire is estimated to be retained in the peat. Overall, accumulation in mires and other types of wetlands is estimated to decrease the fluxes of uranium and thorium from the boreal forest landscape by 30-40 %. The atmospheric deposition of uranium and thorium was also quantified and its contribution to boreal streams was found to be low compared to weathering.

  9. On the structure of thorium and americium adenosine triphosphate complexes.

    PubMed

    Mostapha, Sarah; Fontaine-Vive, Fabien; Berthon, Laurence; Boubals, Nathalie; Zorz, Nicole; Solari, Pier Lorenzo; Charbonnel, Marie Christine; Den Auwer, Christophe

    2014-11-01

    The actinides are chemical poisons and radiological hazards. One challenge to better appraise their toxicity and develop countermeasures in case of exposure of living organisms is to better assess pathways of contamination. Because of the high chemical affinity of those actinide elements for phosphate groups and the ubiquity of such chemical functions in biochemistry, nucleotides and in particular adenosine triphosphate nucleotide (ATP) may be considered critical target building blocks for actinides. Combinations of spectroscopic techniques (Fourier transformed Infra Red [FTIR], Electrospray Ionization Mass Spectrometry [ESI-MS], and Extended X-ray Absorption Fine Structure [EXAFS]) with quantum chemical calculations have been implemented in order to assess the actinides coordination arrangement with ATP. We describe and compare herein the interaction of ATP with thorium and americium; thorium(IV) as a representative of actinide(IV) like plutonium(IV) and americium(III) as a representative of all heavier actinides. In the case of thorium, an insoluble complex is readily formed. In the case of americium, a behavior identical to that described previously for lutetium has been observed with insoluble and soluble complexes. The comparative study of ATP complexation with Th(IV) and Am(III) shows their ability to form insoluble complexes for which a structural model has been proposed by analogy with previously described Lu(III) complexes.

  10. Determination of trace amounts of thorium by electroanalytical techniques.

    PubMed

    Mazzocchin, G A; Daniele, S; Moretto, L M

    1990-03-01

    Trace amounts of thorium have been determined in the presence of uranyl nitrate and ammonium diuranate (as interferents) by cyclic voltammetry, differential-pulse polarography, differential-pulse voltammetry, square-wave voltammetry and anodic-stripping voltammetry. The determination is based on the substitution of thorium for copper, lead and cadmium in their EDTA complexes and voltammetric measurement of the displaced metal ion. The detection limits ranged between 2 x 10(-7) and 1 x 10(-6)M (r.s.d. 2-7%) for solutions free from the uranium compounds, and between 8 x 10(-7) and 5 x 10(-6)M (r.s.d. 3-5%) in the presence of the uranium compounds at concentrations up to about 1000 times that of thorium. The detection limits depend on both the particular technique and the EDTA complex employed. Anodic-stripping voltammetry gave detection limits of 8 x 10(-8) and 10(-7)M in the absence and presence of uranium respectively.

  11. Sulfurization behavior of thorium dioxide with carbon disulfide

    NASA Astrophysics Data System (ADS)

    Sato, N.; Kirishima, A.

    2011-07-01

    A novel reprocessing process based on sulfide chemistry has been proposed for the recovery of nuclear materials from spent fuel. To apply the sulfide process in the thorium fuel cycle, the sulfurization behavior of thorium dioxide (ThO 2) with CS 2 was examined as a basic study. When thorium dioxide powder reacted with a mixture gas of Ar and CS 2 at different temperatures in a quartz reaction tube, the phases after the reaction were identified by the X-ray diffraction method. At temperatures lower than 673 K, ThO 2 was found to be stable because the lattice parameter of the ThO 2 phases does not change with increasing sulfurization temperatures. However, the weight gradually increased, suggesting that a small amount of sulfur was trapped in the lattice from the sulfurization. The formation of the intermediate phase ThOS was observed at 973 K. At 1073 K, both the ThOS and ThS 2 phases were observed. Finally, a single phase of ThS 2 was obtained at temperatures higher than 1173 K. The obtained results were compared with the thermodynamic consideration by using the potential diagram of the Th-S 2-O 2 system and the experimental results were in good agreement with the thermodynamic considerations.

  12. Comparison of thorium(IV) and uranium(VI) carboxyphosphonates.

    PubMed

    Adelani, Pius O; Albrecht-Schmitt, Thomas E

    2010-06-21

    The hydrothermal reactions of thorium nitrate and uranyl acetate with carboxyphenylphosphonic acid and HF result in the formation of ThF(2)(PO(3)C(6)H(4)CO(2)H) and UO(2)(PO(3)HC(6)H(4)CO(2)H)(2).2H(2)O, respectively. ThF(2)(PO(3)C(6)H(4)CO(2)H) adopts a pillared structure constructed from thorium oxyfluoride layers built from [ThO(4)F(4)] units that are bridged by carboxyphenylphosphonate to yield a three-dimensional network. UO(2)(PO(3)HC(6)H(4)CO(2)H)(2).2H(2)O forms one-dimensional chains of UO(6) tetragonal bipyramids that are bridged by the phosphonate moiety of the ligand. The carboxylate portion of the structure links the chains together into layers via a hydrogen-bonding network. The higher effective charge and more isotropic coordination of the Th(IV) centers versus the uranium centers contained within uranyl cations allow for coordination by the protonated carboxylate portions of the ligands to the thorium cations, which does not occur with uranium in carboxyphosphonates. UO(2)(PO(3)HC(6)H(4)CO(2)H)(2).2H(2)O displays vibronically coupled fluorescence and the potential for energy transfer from the ligand to the charge-transfer bands of the uranyl cations. The main fluorescence by the ligand is quenched in ThF(2)(PO(3)C(6)H(4)CO(2)H).

  13. Quantification of thorium and uranium sorption to contaminated sediments

    SciTech Connect

    Kaplan, D.I.

    2000-08-01

    Desorption tests using a sequential extraction method were used to characterize and quantify thorium and uranium sorption to contaminated wetland sediments collected from the Savannah River Site located in South Carolina. In situ distribution coefficients, or Kd values (Kd equal to Csolid/Cliquid), were determined. A problem associated with determining desorption Kd values is that it is difficult to identify Csolid, because by definition it must comprise only the fraction that is reversibly (and linearly) sorbed. A series of selective and sequential extractions was used to determine desorption Kd values. Thorium Kd values ranged from 115 to 2255 mL/g. Uranium Kd values ranged from 170 to 6493 mL/g. Compared to sorption Kd values, these desorption Kd values were appreciably greater because they captured the ``aging'' process of the radionuclides with the sediment, making the radionuclide more refractory. Compared to nonsite-specific data, these in situ Kd values improved accuracy, were more defensible, reduced uncertainty, and removed unnecessary conservatism for subsequent transport and risk calculations. Additional tests were conducted to provide geochemical information relevant for selecting appropriate remediation technologies for the contaminated site. Thorium and U were associated with labile fractions and were not concentrated with the smaller sediment particles. These findings suggest that phytoremediation or heap leaching, and not soil washing, are viable remediation approaches for this site.

  14. Thorium biosorption by Aspergillus fumigatus, a filamentous fungal biomass.

    PubMed

    Bhainsa, Kuber C; D'Souza, Stanislaus F

    2009-06-15

    Thorium biosorption by Aspergillus fumigatus was carried out in a batch reactor to study the effect of initial pH and metal ion concentration, contact time, biomass dose and kinetics and equilibrium Th uptake. Thorium(IV) uptake by A. fumigatus was pH dependent (pH range, 2.0-6.0) and maximum sorption was observed at pH 4.0. The uptake was rapid and the biosorption process reached equilibrium within 2h of contact times at pH 2-4 and initial Th concentration of 50 and 100mg/L. The kinetics data fitted well to Lagergren's pseudo-second-order rate equation (r(2)>0.99). A maximum initial sorption rate of 71.94 (mg/g min) and second-order rate constant of 7.82 x 10(-2) (g/mg min) were observed at pH 4.0, 50 mg Th/L. The observed maximum uptake of thorium was 370 mg Th/g at equilibrium. Biosorption process could be well described by Langmuir isotherm in comparison to Freundlich and Temkin isotherms. Sodium bicarbonate was the most efficient desorbing reagent with desorption efficiency of more than 99%. Environmental scanning electron micrograph (ESEM) showed that the surface of the biomass after desorption was intact.

  15. Liquid fuel molten salt reactors for thorium utilization

    SciTech Connect

    Gehin, Jess C.; Powers, Jeffrey J.

    2016-04-08

    Molten salt reactors (MSRs) represent a class of reactors that use liquid salt, usually fluoride- or chloride-based, as either a coolant with a solid fuel (such as fluoride salt-cooled high temperature reactors) or as a combined coolant and fuel with fuel dissolved in a carrier salt. For liquid-fuelled MSRs, the salt can be processed online or in a batch mode to allow for removal of fission products as well as introduction of fissile fuel and fertile materials during reactor operation. The MSR is most commonly associated with the 233U/thorium fuel cycle, as the nuclear properties of 233U combined with the online removal of parasitic absorbers allow for the ability to design a thermal-spectrum breeder reactor; however, MSR concepts have been developed using all neutron energy spectra (thermal, intermediate, fast, and mixed-spectrum zoned concepts) and with a variety of fuels including uranium, thorium, plutonium, and minor actinides. Early MSR work was supported by a significant research and development (R&D) program that resulted in two experimental systems operating at ORNL in the 1960s, the Aircraft Reactor Experiment and the Molten Salt Reactor Experiment. Subsequent design studies in the 1970s focusing on thermal-spectrum thorium-fueled systems established reference concepts for two major design variants: (1) a molten salt breeder reactor (MSBR), with multiple configurations that could breed additional fissile material or maintain self-sustaining operation; and (2) a denatured molten salt reactor (DMSR) with enhanced proliferation-resistance. T MSRs has been selected as one of six most promising Generation IV systems and development activities have been seen in fast-spectrum MSRs, waste-burning MSRs, MSRs fueled with low-enriched uranium (LEU), as well as more traditional thorium fuel cycle-based MSRs. This study provides an historical background of MSR R&D efforts, surveys and summarizes many of the recent development, and provides

  16. Liquid fuel molten salt reactors for thorium utilization

    DOE PAGES

    Gehin, Jess C.; Powers, Jeffrey J.

    2016-04-08

    Molten salt reactors (MSRs) represent a class of reactors that use liquid salt, usually fluoride- or chloride-based, as either a coolant with a solid fuel (such as fluoride salt-cooled high temperature reactors) or as a combined coolant and fuel with fuel dissolved in a carrier salt. For liquid-fuelled MSRs, the salt can be processed online or in a batch mode to allow for removal of fission products as well as introduction of fissile fuel and fertile materials during reactor operation. The MSR is most commonly associated with the 233U/thorium fuel cycle, as the nuclear properties of 233U combined with themore » online removal of parasitic absorbers allow for the ability to design a thermal-spectrum breeder reactor; however, MSR concepts have been developed using all neutron energy spectra (thermal, intermediate, fast, and mixed-spectrum zoned concepts) and with a variety of fuels including uranium, thorium, plutonium, and minor actinides. Early MSR work was supported by a significant research and development (R&D) program that resulted in two experimental systems operating at ORNL in the 1960s, the Aircraft Reactor Experiment and the Molten Salt Reactor Experiment. Subsequent design studies in the 1970s focusing on thermal-spectrum thorium-fueled systems established reference concepts for two major design variants: (1) a molten salt breeder reactor (MSBR), with multiple configurations that could breed additional fissile material or maintain self-sustaining operation; and (2) a denatured molten salt reactor (DMSR) with enhanced proliferation-resistance. T MSRs has been selected as one of six most promising Generation IV systems and development activities have been seen in fast-spectrum MSRs, waste-burning MSRs, MSRs fueled with low-enriched uranium (LEU), as well as more traditional thorium fuel cycle-based MSRs. This study provides an historical background of MSR R&D efforts, surveys and summarizes many of the recent development, and provides analysis comparing

  17. Spatial distribution of thorium fission rate in a fast spallation and fission neutron field: An experimental and Monte Carlo study

    NASA Astrophysics Data System (ADS)

    Borger, J. J.; Hashemi-Nezhad, S. R.; Alexiev, D.; Brandt, R.; Westmeier, W.; Thomauske, B.; Adam, J.; Kadykov, M.; Tiutiunnikov, S.

    2012-02-01

    The Energy plus Transmutation (EpT) set-up of the Joint Institute for Nuclear Research (JINR), Dubna, Russia is composed of a lead spallation target surrounded by a blanket of natural uranium. The resultant neutron spectrum is a combination of spallation and fission spectra, modified by a reflective external layer of polyethylene and an internal absorbing layer of cadmium. The EpT set-up was irradiated with a beam of 4 GeV deuterons from the Nuclotron Accelerator at JINR. The spatial distribution of thorium fission rate within the assembly was determined experimentally, using a fission track detector technique, and compared with Monte Carlo predictions of the MCNPX code. Contributions of neutrons, protons, deuterons, photons and pions to total fission were taken into account. Close agreement between the experimental and calculated results was found.

  18. Hydration and hydrolysis of thorium(IV) in aqueous solution and the structures of two crystalline thorium(IV) hydrates.

    PubMed

    Torapava, Natallia; Persson, Ingmar; Eriksson, Lars; Lundberg, Daniel

    2009-12-21

    Solid octaaqua(kappa(2)O-perchlorato)thorium(IV) perchlorate hydrate, [Th(H(2)O)(8)(ClO(4))](ClO(4))(3).H(2)O, 1, and aquaoxonium hexaaquatris(kappaO-trifluoromethanesulfonato)thorium(IV) trisaquahexakis(kappaO-trifluoromethanesulfonato)thorinate(IV), H(5)O(2)[Th(H(2)O)(6)(OSO(2)CF(3))(3)][Th(H(2)O)(3)(OSO(2)CF(3))(6)], 2, were crystallized from concentrated perchloric and trifluoromethanesulfonic acid solutions, respectively. 1 adopts a severely distorted tricapped trigonal prismatic configuration with an additional oxygen from the perchlorate ion at a longer distance. 2 consists of individual hexaaquatris(kappaO-trifluoromethanesulfonato)thorium(IV) and trisaquahexakis(kappaO-trifluoromethanesulfonato)thorinate(IV) ions and an aquaoxonium ion bridging these two ions through hydrogen bonding. The hydrated thorium(IV) ion is nine-coordinated in aqueous solution as determined by extended X-ray absorption fine structure (EXAFS) and large angle X-ray scattering (LAXS). The LAXS studies also showed a second hydration sphere of about 18 water molecules, and traces of a 3rd hydration sphere. Structural studies in aqueous solution of the hydrolysis products of thorium(IV) have identified three different types of hydrolysis species: a mu(2)O-hydroxo dimer, [Th(2)(OH)(2)(H(2)O)(12)](6+), a mu(2)O-hydroxo tetramer, [Th(4)(OH)(8)(H(2)O)(16)](8+), and a mu(3)O-oxo hexamer, [Th(6)O(8)(H(2)O)(n)](8+). Detailed structures of these three hydrolysis species are given. A compilation of reported solid state structures of actinoid(IV) compounds with oxygen donor ligands show a strong correlation between the An-O bond distance and the coordination number. The earlier reported U-O bond distance in the hydrated uranium(IV) ion in aqueous solution, confirmed in this study, is related to nine-coordination. The hydrated tri- and tetravalent actinoid ions in aqueous solution all seem to be nine-coordinated. The trivalent ions show a significant difference in bond distance to prismatic and

  19. Why reconsider the thorium fuel cycle?

    SciTech Connect

    Krahn, S.; Croff, A.; Ault, T.; Wymer, R.

    2013-07-01

    In this paper we have endeavored to present the available technical information on the potential use of Th in nuclear fuel cycle (FC) applications as compared to U without subjective evaluations. Where helpful, we have compared the technical attributes of Th-232 as a fertile isotope and U-233 as a fissile isotope with other similar isotopes (i.e., U-238, and U-235 and Pu-239, respectively). In addition, we have summarized (a) experience gained to-date with fabricating and reprocessing of Th-232/U-233 fuels, (b) factors concerning Th fuel irradiation in both test reactors and power reactors, and (c) differences in the backend of the FC with emphasis on repository risks. As might be expected, many technical aspects of Th vs. U have not changed since the sixties. However, there are some factors elaborated in this paper that have changed. Changes potentially encouraging Th use are: (a) the ability to recover large amounts of Th as a byproduct with small attendant costs and environmental impacts, (b) the potential to produce fewer minor actinides (MA) and less Pu during power production, and (c) increased concerns about proliferation which might be somewhat mitigated by the high radioactivity and amenability to isotopic dilution of U-233. Changes challenging Th utilization are: (a) obtaining sufficient experience handling Th/U-233 fuels, (b) the existence of large inventories of depleted U and continuing discovery of large U resources, and (c) recognition that the extent to which U-233 might mitigate proliferation concerns is not as large as originally hoped.

  20. Preliminary summary review of thorium-bearing mineral occurrences in Alaska

    USGS Publications Warehouse

    Bates, Robert G.; Wedow, Helmuth

    1952-01-01

    Thorium-bearing minerals are known at 47 localities in Alaska. At these localities the thorium occurs as a major constituent or in minor amounts as an impurity in one or more of the following 12 minerals: allanite, columbite, ellsworthite, eschynite, gummite, monazite, orangite, parisite, thorianite, thorite, xenotime, and zircon. In addition other minerals, such as biotite and sphene, are radioactive and may contain thorium. Several unidentified columbate minerals with uranium or thorium and uranium as major constituents have been recognized at some localities. The distribution, by type of deposit, of the 57 thorium occurrences is as follows: lode - 3, lode and placer - 1, granitic rock - 3, granitic rock and related placer - 14, and placer - 26. Of the four lode occurrences only the radioactive veins at Salmon Bay in southeastern Alaska and the contact metamorphic deposit in the Nixon Fork area of central Alaska warrant further consideration, although insufficient data are available to determine whether these two deposits have commercial possibilities. The remaining occurrences of thorium-bearing minerals in Alaska are limited to placer deposits and disseminations of accessory minerals in granitic rocks. In most of these occurrences the thorium-bearing minerals occur in only trace amounts and consequently warrent little further consideration. More data are needed to determine the possibilities of byproduct recovery of thorium-bearing minerals from several of the gold and tin placers.

  1. Separation of thorium ions from wolframite and scandium concentrates using graphene oxide.

    PubMed

    Jankovský, Ondřej; Sedmidubský, David; Šimek, Petr; Klímová, Kateřina; Bouša, Daniel; Boothroyd, Chris; Macková, Anna; Sofer, Zdeněk

    2015-10-14

    The separation of rare metals from the ores and commercially available compounds is an important issue due to the need of their high purity in advanced materials and devices. Important examples of two highly important elements that co-exist in the ores are scandium and thorium. Scandium containing ores and consequently also commercially available scandium compounds often contain traces of thorium which is very difficult to separate. We used graphene oxide for the selective sorption of thorium ions from scandium and thorium mixtures originating from the mined ores as well as from commercially available scandium salts. Our results showed that graphene oxide has an extreme affinity towards thorium ions. After the sorption process the graphene oxide contained over 20 wt% of thorium while the amount of scandium sorbed on GO was very low. This phenomenon of high sorption selectivity of graphene oxide can be applied in industry for the purification of various chemicals containing scandium and for separation of thorium containing mixtures. Alternatively, this methodology can be used for preconcentration of thorium from low-grade ores and its further use in the new generation of nuclear reactors.

  2. New Twists and Turns for Actinide Chemistry: Organometallic Infinite Coordination Polymers of Thorium Diazide.

    PubMed

    Monreal, Marisa J; Seaman, Lani A; Goff, George S; Michalczyk, Ryszard; Morris, David E; Scott, Brian L; Kiplinger, Jaqueline L

    2016-03-07

    Two organometallic 1D infinite coordination polymers and two organometallic monometallic complexes of thorium diazide have been synthesized and characterized. Steric control of these self-assembled arrays, which are dense in thorium and nitrogen, has also been demonstrated: infinite chains can be circumvented by using steric bulk either at the metallocene or with a donor ligand in the wedge.

  3. 76 FR 30696 - Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-26

    .... Funds for reimbursement will be provided from the Uranium Enrichment Decontamination and Decommissioning... Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites AGENCY: Department of... eligible active uranium and thorium processing site licensees for reimbursement under Title X of the Energy...

  4. Uranium and thorium content in long-tailed ducks (Clangula hyemalis L.).

    PubMed

    Szefer, P; Falandysz, J

    1983-08-01

    Concentrations of uranium and thorium have been determined in liver, breast muscle, leg muscle, stomach and heart of long-tailed ducks wintering in Gdańsk Bay during 1980-81. The highest concentration of uranium and thorium was found in stomach, and the lowest in breast muscle.

  5. Metallurgical and mechanical properties of thorium-doped Ir-0. 3% W alloys

    SciTech Connect

    Liu, C.T.; Inouye, H.; Schaffhauser, A.C.

    1980-04-01

    Metallurgical and mechanical properties of Ir-0.3% W alloys have been studied as a function of thorium concentration in the range 0 to 1000 ppM by weight. The solubility limit of thorium in Ir-0.3% W is below 30 ppM. Above this limit, the excess thorium reacts with iridium to form second-phase particles. Thorium additions raise the recrystallization temperature and effectively retard grain growth at high temperatures. Tensile tests at 650/sup 0/C show that the alloy without thorium additions (undoped alloy) fractured by grainboundary (GB) separation, while the alloys doped with less than 500 ppM thorium failed mainly by transgranular fracture at 650/sup 0/C. Intergranular fracture in the doped alloys is suppressed by GB segregation of thorium, which improves the mechanical properties of the boundary. The impact properties of the alloys were correlated with test temperature, grain size, and heat treatment. The impact ductility increases with test temperature and decreases with grain size. For a given grain size, particularly in the fine-grain size range, the thorium-doped alloys are much more ductile and resistant to GB fracture. All of these results can be correlated on the basis of stress concentration on GBs by using a dislocation pileup model.

  6. The Spectrum of Thorium from 250 nm to 5500 nm: Ritz Wavelengths and Optimized Energy Levels

    NASA Astrophysics Data System (ADS)

    Redman, Stephen L.; Nave, Gillian; Sansonetti, Craig J.

    2014-03-01

    We have made precise observations of a thorium-argon hollow cathode lamp emission spectrum in the region between 350 nm and 1175 nm using a high-resolution Fourier transform spectrometer. Our measurements are combined with results from seven previously published thorium line lists to re-optimize the energy levels of neutral, singly, and doubly ionized thorium (Th I, Th II, and Th III). Using the optimized level values, we calculate accurate Ritz wavelengths for 19, 874 thorium lines between 250 nm and 5500 nm (40, 000 cm-1 to 1800 cm-1). We have also found 102 new thorium energy levels. A systematic analysis of previous measurements in light of our new results allows us to identify and propose corrections for systematic errors in Palmer & Engleman and typographical errors and incorrect classifications in Kerber et al. We also found a large scatter with respect to the thorium line list of Lovis & Pepe. We anticipate that our Ritz wavelengths will lead to improved measurement accuracy for current and future spectrographs that make use of thorium-argon or thorium-neon lamps as calibration standards.

  7. THE SPECTRUM OF THORIUM FROM 250 nm TO 5500 nm: RITZ WAVELENGTHS AND OPTIMIZED ENERGY LEVELS

    SciTech Connect

    Redman, Stephen L.; Nave, Gillian; Sansonetti, Craig J.

    2014-03-01

    We have made precise observations of a thorium-argon hollow cathode lamp emission spectrum in the region between 350 nm and 1175 nm using a high-resolution Fourier transform spectrometer. Our measurements are combined with results from seven previously published thorium line lists to re-optimize the energy levels of neutral, singly, and doubly ionized thorium (Th I, Th II, and Th III). Using the optimized level values, we calculate accurate Ritz wavelengths for 19, 874 thorium lines between 250 nm and 5500 nm (40, 000 cm{sup –1} to 1800 cm{sup –1}). We have also found 102 new thorium energy levels. A systematic analysis of previous measurements in light of our new results allows us to identify and propose corrections for systematic errors in Palmer and Engleman and typographical errors and incorrect classifications in Kerber et al. We also found a large scatter with respect to the thorium line list of Lovis and Pepe. We anticipate that our Ritz wavelengths will lead to improved measurement accuracy for current and future spectrographs that make use of thorium-argon or thorium-neon lamps as calibration standards.

  8. Demonstration of iron and thorium in autopsy tissues by x-ray microanalysis

    SciTech Connect

    Landas, S.; Turner, J.W.; Moore, K.C.; Mitros, F.A.

    1984-03-01

    We performed x-ray microanalysis of autopsy specimens using a scanning-transmission electron microscopy mode. Tissues were obtained at necropsy from a patient with history of angiography using thorium dioxide and from a patient with hemochromatosis. X-ray microanalysis confirmed the presence of thorium and iron in their respective tissues. Effects of staining reagents were examined.

  9. Uranium and thorium sequestration by a Pseudomonas sp.: mechanism and chemical characterization.

    PubMed

    Kazy, Sufia K; D'Souza, S F; Sar, Pinaki

    2009-04-15

    The mechanism and chemical nature of uranium and thorium sequestration by a Pseudomonas strain was investigated by transmission electron microscopy, energy dispersive X-ray (EDX) analysis, FTIR spectroscopy and X-ray diffractometry. Atomic force microscopy (AFM) used in the tapping mode elucidated the morphological changes in bacterial cells following uranium and thorium binding. Transmission electron microscopy revealed intracellular sequestration of uranium and thorium throughout the cell cytoplasm with electron dense microprecipitations of accumulated metals. Energy dispersive X-ray analysis confirmed the cellular deposition of uranium and thorium. EDX and elemental analysis of sorption solution indicated the binding of uranium and thorium by the bacterial biomass via displacement of cellular potassium and calcium. The strong involvement of cellular phosphate, carboxyl and amide groups in radionuclide binding was ascertained by FTIR spectroscopy. X-ray powder diffraction (XRD) analyses confirmed cellular sequestration of crystalline uranium and thorium phosphates. Overall results indicate that a combined ion-exchange-complexation-microprecipitation mechanism could be involved in uranium and thorium sequestration by this bacterium. Atomic force microscopy and topography analysis revealed an undamaged cell surface with an increase in cell length, width and height following radionuclide accumulation. The arithmetic average roughness (R(a)) and root mean square (RMS) roughness (R(q)) values indicated an increase in surface roughness following uranium and thorium sequestration.

  10. Establishing bounding internal dose estimates for thorium activities at Rocky Flats.

    PubMed

    Ulsh, Brant A; Rich, Bryce L; Chew, Melton H; Morris, Robert L; Sharfi, Mutty; Rolfes, Mark R

    2008-07-01

    As part of an evaluation of a Special Exposure Cohort petition filed on behalf of workers at the Rocky Flats Plant, the National Institute for Occupational Safety and Health (NIOSH) was required to demonstrate that bounding values could be established for radiation doses due to the potential intake of all radionuclides present at the facility. The main radioactive elements of interest at Rocky Flats were plutonium and uranium, but much smaller quantities of several other elements, including thorium, were occasionally handled at the site. Bounding potential doses from thorium has proven challenging at other sites due to the early historical difficulty in detecting this element through urinalysis methods and the relatively high internal dose delivered per unit intake. This paper reports the results of NIOSH's investigation of the uses of thorium at Rocky Flats and provides bounding dose reconstructions for these operations. During this investigation, NIOSH reviewed unclassified reports, unclassified extracts of classified materials, material balance and inventory ledgers, monthly progress reports from various groups, and health physics field logbooks, and conducted interviews with former Rocky Flats workers. Thorium operations included: (1) an experimental metal forming project with 240 kg of thorium in 1960; (2) the use of pre-formed parts in weapons mockups; (3) the removal of Th from U; (4) numerous analytical procedures involving trace quantities of thorium; and (5) the possible experimental use of thorium as a mold coating compound. The thorium handling operations at Rocky Flats were limited in scope, well-monitored and documented, and potential doses can be bounded.

  11. A first-principles study of He, Xe, Kr and O incorporation in thorium carbide

    NASA Astrophysics Data System (ADS)

    Pérez Daroca, D.; Llois, A. M.; Mosca, H. O.

    2015-05-01

    Thorium-based materials are currently being investigated in relation with their potential utilization in Generation-IV reactors as nuclear fuels. Understanding the incorporation of fission products and oxygen is very important to predict the behavior of nuclear fuels. A first approach to this goal is the study of the incorporation energies and stability of these elements in the material. By means of first-principles calculations within the framework of density functional theory, we calculate the incorporation energies of He, Xe, Kr and O atoms in Th and C vacancy sites, in tetrahedral interstitials and in Schottky defects along the <1 1 1> and <1 0 0> directions. We also analyze atomic displacements, volume modifications and Bader charges. This kind of results for ThC, to the best authors' knowledge, have not been obtained previously, neither experimentally, nor theoretically. This should deal as a starting point towards the study of the complex behavior of fission products in irradiated ThC.

  12. A dynamic fuel cycle analysis for a heterogeneous thorium-DUPIC recycle in CANDU reactors

    SciTech Connect

    Jeong, C. J.; Park, C. J.; Choi, H.

    2006-07-01

    A heterogeneous thorium fuel recycle scenario in a Canada deuterium uranium (CANDU) reactor has been analyzed by the dynamic analysis method. The thorium recycling is performed through a dry process which has a strong proliferation resistance. In the fuel cycle model, the existing nuclear power plant construction plan was considered up to 2016, while the nuclear demand growth rate from the year 2016 was assumed to be 0%. In this analysis, the spent fuel inventory as well as the amount of plutonium, minor actinides, and fission products of a multiple thorium recycling fuel cycle were estimated and compared to those of the once-through fuel cycle. The analysis results have shown that the heterogeneous thorium fuel cycle can be constructed through the dry process technology. It is also shown that the heterogeneous thorium fuel cycle can reduce the spent fuel inventory and save on the natural uranium resources when compared with the once-through cycle. (authors)

  13. Determination of thorium by ICP-MS and ICP-OES.

    PubMed

    Holmes, L

    2001-01-01

    Natural thorium (232-Th) has traditionally been measured by radiometric techniques such as alpha and gamma spectrometry. However. with both ICP-OES and ICP-MS instruments becoming relatively common in many analytical laboratories. these techniques have become more acceptable in thorium analysis. This paper will briefly describe an overview of the instrumentation currently available and the techniques themselves applied to thorium analysis. Both techniques have low detection limits and require little sample treatment after the sample digestion. Routine sample analysis time is short and spectra easy to interpret. usually giving results with low uncertainties, Whereas ICP-OES measures total thorium only, ICP-MS also offers the potential to measure other long-lived thorium isotopes (t 1/2 > 10(4) years), such as 232Th. However, other important isotopes, such as 228Th. are still out of reach for routine analysis. The main disadvantage of the techniques is the requirement for a sample digestion stage.

  14. Fast Thorium Molten Salt Reactors Started with Plutonium

    SciTech Connect

    Merle-Lucotte, E.; Heuer, D.; Le Brun, C.; Brissot, R.; Liatard, E.; Meplan, O.; Nuttin, A.

    2006-07-01

    One of the pending questions concerning Molten Salt Reactors based on the {sup 232}Th/{sup 233}U fuel cycle is the supply of the fissile matter, and as a consequence the deployment possibilities of a fleet of Molten Salt Reactors, since {sup 233}U does not exist on earth and is not yet produced in the current operating reactors. A solution may consist in producing {sup 233}U in special devices containing Thorium, in Pressurized Water or Fast Neutrons Reactors. Two alternatives to produce {sup 233}U are examined here: directly in standard Molten Salt Reactors started with Plutonium as fissile matter and then operated in the Th/{sup 233}U cycle; or in dedicated Molten Salt Reactors started and fed with Plutonium as fissile matter and Thorium as fertile matter. The idea is to design a critical reactor able to burn the Plutonium and the minor actinides presently produced in PWRs, and consequently to convert this Plutonium into {sup 233}U. A particular reactor configuration is used, called 'unique channel' configuration in which there is no moderator in the core, leading to a quasi fast neutron spectrum, allowing Plutonium to be used as fissile matter. The conversion capacities of such Molten Salt Reactors are excellent. For Molten Salt Reactors only started with Plutonium, the assets of the Thorium fuel cycle turn out to be quickly recovered and the reactor's characteristics turn out to be equivalent to Molten Salt Reactors operated with {sup 233}U only. Using a combination of Molten Salt Reactors started or operated with Plutonium and of Molten Salt Reactors started with {sup 233}U, the deployment capabilities of these reactors fully satisfy the condition of sustainability. (authors)

  15. Thorium Chemistry in Oxo-Tellurium System under Extreme Conditions.

    PubMed

    Xiao, Bin; Kegler, Philip; Bosbach, Dirk; Alekseev, Evgeny V

    2017-03-06

    Through the use of a high-temperature/high-pressure synthesis method, four thorium oxo-tellurium compounds with different tellurium valence states were isolated. The novel inorganic phases illustrate the intrinsic complexity of the actinide tellurium chemistry under extreme conditions of pressure and temperature. Th2Te3O11 is the first instance of a mixed-valent oxo-tellurium compound, and at the same time, Te exhibits three different coordination environments (Te(IV)O3, Te(IV)O4, and Te(VI)O6) within a single structure. These three types of Te polyhedra are further fused together, resulting in a [Te3O11](8-) fragment. Na4Th2(Te(VI)3O15) and K2Th(Te(VI)O4)3 are the first alkaline thorium tellurates described in the literature. Both compounds are constructed from ThO9 tricapped trigonal prisms and Te(VI)O6 octahedra. Na4Th2(Te(VI)3O15) is a three-dimensional framework based on Th2O15 and Te2O10 dimers, while K2Th(Te(VI)O4)3 contains tungsten oxide bronze like Te layers linked by ThO9 polyhedra. The structure of β-Th(Te(IV)O3)(SO4) is built from infinite thorium chains cross-linked by Te(IV)O3(2-) and SO4(2-) anions. Close structural analysis suggests that β-Th(Te(IV)O3)(SO4) is highly related to the structure of α-Th(SeO4)2. Additionally, the Raman spectra are recorded and the characteristic peaks are assigned based on a comparison of reported tellurites or tellurates.

  16. Wet Mountains, Colorado, thorium investigations, 1952-1954

    USGS Publications Warehouse

    Christman, Robert Adam; Brock, M.R.; Pearson, R.C.; Singewald, Q.D.

    1954-01-01

    A 22-square mile tract (McKinley Mountain Area) of pre-Cambrian rocks and veins containing thorium was mapped at the scale of 1:6,000. This tract lies on the west flank of the Wet Mountains, Custer and Fremont Counties, northeast of Westcliffe, Colo. The bedrock is a complexly interlayered sequence of gneisses of metasedimetary origin, migmatite and granitic gneisses that have been transected by an albite syenite stock and numerous northwest-trending dikes, veins, and fractures. Hornblende-plagioclase and biotite-quartz-plagioclase gneisses are the principal metasedimentary rocks; pyroxene-scapolite, garnet, sillimanite, and quartzite zones are locally present. The most prominent rock is a poorly foliated, microcline, alaskitic granite gneiss which occurs as layers ranging from more than 500 feet in thickness down to migmatitic “lit-par-lit” type of injections less than an inch thick. Of less wide distribution, but of similar occurrence, are quartz monzonite and leuco-granodiorite gneisses. Although the foliation of the rocks generally is steep and trends northeast over most of the area, several northeast-trending folds have been mapped in the northern half of the area; a vertically plunging fold occurs in the southwest. The albite syenite is nonfoliated and is about 595 million years old (late pre-Cambrian) by the Larsen zircon method of age determination. Many of the dikes are related to the stock. More than 800 radioactive occurrences were found along the northwest-trending veins. Almost all the radioactivity is due to thorium which in its purest form occurs as a hydrated thorite-like mineral. The veins also contain carbonate minerals, barite, quartz, red and yellow iron oxides, and minor sulfides; no genetic relation of these minerals to the thorium has been established. Although most of the deposits are only weakly radioactive, richer concentrations are scattered as pockets and lenses along the veins.

  17. Configurational analysis of uranium-doped thorium dioxide

    NASA Astrophysics Data System (ADS)

    Shields, A. E.; Ruiz-Hernandez, S. E.; de Leeuw, N. H.

    2015-04-01

    While thorium dioxide is already used industrially in high temperature applications, more insight is needed about the behaviour of the material as part of a mixed-oxide (MOX) nuclear fuel, incorporating uranium. We have developed a new interatomic potential model, commensurate with a prominent existing UO2 potential, to conduct configurational analyses of uranium-doped ThO2 supercells. Using the GULP and Site Occupancy Disorder (SOD) computational codes, we have analysed the distribution of low concentrations of uranium in the bulk material, but have not observed the formation of uranium clusters or a single dominant configuration.

  18. Neutronic calculations for CANDU thorium systems using Monte Carlo techniques

    NASA Astrophysics Data System (ADS)

    Saldideh, M.; Shayesteh, M.; Eshghi, M.

    2014-08-01

    In this paper, we have investigated the prospects of exploiting the rich world thorium reserves using Canada Deuterium Uranium (CANDU) reactors. The analysis is performed using the Monte Carlo MCNP code in order to understand how much time the reactor is in criticality conduction. Four different fuel compositions have been selected for analysis. We have obtained the infinite multiplication factor, k∞, under full power operation of the reactor over 8 years. The neutronic flux distribution in the full core reactor has already been investigated.

  19. Gas-phase energetics of thorium fluorides and their ions.

    PubMed

    Irikura, Karl K

    2013-02-14

    Gas-phase thermochemistry for neutral ThF(n) and cations ThF(n)(+) (n = 1-4) is obtained from large-basis CCSD(T) calculations, with a small-core pseudopotential on thorium. Electronic partition functions are computed with the help of relativistic MRCI calculations. Geometries, vibrational spectra, electronic fine structure, and ion appearance energies are tabulated. These results support the experimental results by Lau, Brittain, and Hildenbrand for the neutral species, except for ThF. The ion thermochemistry is presented here for the first time.

  20. SOLVENT EXTRACTION OF THORIUM VALUES FROM AQUEOUS SOLUTIONS

    DOEpatents

    Warf, J.C.

    1959-04-21

    The separation of thorium values from rare earth metals contained ln aqueous solutions by means of extraction with a water immiscible alkyl phosphate diluted with a hydrocarbon such as hexane is described. While the extraction according to this invention may be carried out from any aqueous salt solution, it is preferred to use solutions containing free mineral acid. Hydrochloric acid and in particular nitric acid are sultable in a concentration ranging from 0.1 to 7 normal. The higher acid concentration results in higher extraction values.

  1. Outdoor thoron and progeny in a thorium rich area with old decommissioned mines and waste rock.

    PubMed

    Haanes, Hallvard; Finne, Ingvild E; Kolstad, Trine; Mauring, Alexander; Dahlgren, Sven; Rudjord, Anne Liv

    2016-10-01

    Radon ((222)Rn), thoron ((220)Rn) and their decay products may reach high levels in areas of high natural background radiation, with increased risk associated with mining areas. Historically, the focus has mostly been placed upon radon and progeny (RnP), but recently there have been reports of significant contributions to dose from thoron progeny (TnP). However, few direct measurements of TnP exist under outdoor conditions. Therefore, we assessed the outdoor activity concentrations of radon, thoron and TnP in an area of igneous bedrock with extreme levels of radionuclides in the thorium decay series. The area is characterized by decommissioned mines and waste rock deposits, which provide a large surface area for radon and thoron emanation and high porosity enhancing exhalation. Extreme levels of thorium and thoron have previously been reported from this area and to improve dose rate estimates we also measured TnP using filter sampling and time-integrating alpha track detectors. We found high to extreme levels of thoron and TnP and the associated dose rates relevant for inhalation were up to 8 μSvh(-1) at 100 cm height. Taking gamma irradiation and RnP into account, significant combined doses may result from occupancies in this area. This applies to recreational use of the area and especially previous and planned road-works, which in the worst case could involve doses as large as 23.4 mSv y(-1). However, radon and thoron levels were much more intense on a hot September day than during time-integrated measurements made the subsequent colder and wetter month, especially along the ground. This may be explained by cold air observed flowing out from inside the mines through a drainage pipe adjacent to the measurement stations. During warm periods, activity concentrations may therefore be due to both local exhalation from the ground and air ventilating from the mines. However, a substantially lower level of TnP was measured on the September day using filter sampling

  2. Dysfonctionnements radio-induits du transport colique chez le rat

    NASA Astrophysics Data System (ADS)

    François, A.; Lebrun, F.; Ksas, B.; Aigueperse, J.; Gourmelon, P.; MacNaughton, W. K.; Griffiths, N. M.

    1998-04-01

    The symptom commonly associated with whole body irradiation is diarrhoea, a still quite obscure phenomenon, which leads to decreased chance of cure of irradiated people. The aim of this study was to provide evidence for dysfunction of intestinal water and electrolyte transport regulation by the enteric nervous system after exposure to ionising radiation. This study shows decreased capacity of enteric nervous system to influence colonic transport 3days after irradiation, correlated to a diminished response to a neurotransmitter: serotonin. Radio-induced diarrhea may result from epithelial structural injury but also from impaired regulatory processes of intestinal transport. L'un des symptômes majeurs d'une irradiation corporelle totale ou abdominale est l'apparition de diarrhées, dont les causes sont encore mal connues, et qui mettent en jeu le pronostique vital de l'individu irradié. Cette étude vise à mettre en évidence l'atteinte de la régulation du transport intestinal d'eau et d'électrolytes par les rayonnements ionisants. On observe une diminution de la capacité du système nerveux entérique à influencer le transport colique 3jours après irradiation, corrélée à une diminution de la réponse épithéliale à un neurotransmetteur : la sérotonine. Les diarrhées radio-induites résulteraient d'une atteinte structurelle de l'épithélium mais également des processus de régulation du transport intestinal.

  3. Promises and Challenges of Thorium Implementation for Transuranic Transmutation - 13550

    SciTech Connect

    Franceschini, F.; Lahoda, E.; Wenner, M.; Lindley, B.; Fiorina, C.; Phillips, C.

    2013-07-01

    This paper focuses on the challenges of implementing a thorium fuel cycle for recycle and transmutation of long-lived actinide components from used nuclear fuel. A multi-stage reactor system is proposed; the first stage consists of current UO{sub 2} once-through LWRs supplying transuranic isotopes that are continuously recycled and burned in second stage reactors in either a uranium (U) or thorium (Th) carrier. The second stage reactors considered for the analysis are Reduced Moderation Pressurized Water Reactors (RMPWRs), reconfigured from current PWR core designs, and Fast Reactors (FRs) with a burner core design. While both RMPWRs and FRs can in principle be employed, each reactor and associated technology has pros and cons. FRs have unmatched flexibility and transmutation efficiency. RMPWRs have higher fuel manufacturing and reprocessing requirements, but may represent a cheaper solution and the opportunity for a shorter time to licensing and deployment. All options require substantial developments in manufacturing, due to the high radiation field, and reprocessing, due to the very high actinide recovery ratio to elicit the claimed radiotoxicity reduction. Th reduces the number of transmutation reactors, and is required to enable a viable RMPWR design, but presents additional challenges on manufacturing and reprocessing. The tradeoff between the various options does not make the choice obvious. Moreover, without an overarching supporting policy in place, the costly and challenging technologies required inherently discourage industrialization of any transmutation scheme, regardless of the adoption of U or Th. (authors)

  4. Some thorium prospects, Lemhi Pass area, Beaverhead County, Montana

    USGS Publications Warehouse

    Armstrong, Frank C.

    1955-01-01

    The Last Chance group> Brown Bear and Shady Tree claims in Beaverhead County, Mont., were explored for thorium under a Defense Minerals Exploration Administration Contract in 1951 and 1952. The project was undertaken to explore northwest-trending moderately to steep dipping, thorite-bearing quartz-barite-hematite veins. The veins are wall-rock replacements and fissure fillings in faults and shears that cut rocks of the Precambrian Belt series. Recurrent movement along the faults has intense fractured the veins. Quartz iron-oxide minerals, and thorite have been deposited in these fractures. The iron oxides and thorite are intimately associated and were among the last minerals deposited. Because no rare earth or uranium minerals have been found in the veins, it is thought that the small amounts of these elements reported in the analyses must substitute for thorium in the thorite. Under the D. M. E. A. contract the Last Chance vein was traced on surface for a distance of about 1,300 feet; the thickness ranges from about 35 feet to a few inches. Two diamond drill holes cut the vein 240 and 290 feet below the outcrop.

  5. Electrodeposition of uranium and thorium onto small platinum electrodes

    NASA Astrophysics Data System (ADS)

    Reichenberger, Michael A.; Ito, Takashi; Ugorowski, Philip B.; Montag, Benjamin W.; Stevenson, Sarah R.; Nichols, Daniel M.; McGregor, Douglas S.

    2016-03-01

    Preparation of thin U- and Th-coated 0.3 mm diameter Pt working electrodes by the cyclic potential sweep method is described. Uranyl- and thorium hydroxide layers were electrodeposited from ethanol solutions containing 0.02 M natural uranyl and 0.02 M natural thorium nitrate, each with 3.6 M ammonium nitrate. The cell for electrodeposition was specially developed in order to accommodate the small working electrodes for this research by including a working electrode probe, 3-D translation stage, and microscope. The source material deposition was analyzed using digital microscopy and scanning electron microscopy, and confirmed using x-ray fluorescence measurements. The appropriate potential range for electrodeposition was determined to be -0.62 V to -0.64 V for a 0.3 mm diameter Pt working electrode placed 1 cm from the counter electrode. Smooth, uniform deposition was observed near the central region of the working electrode, while surface cracking and crystalline formations were found near the edge of the working electrode. The final procedure for sample substrate preparation, electrolytic solution preparation and electrodeposition are described.

  6. Uranium-thorium-lead isotope relations in lunar materials.

    PubMed

    Silver, L T

    1970-01-30

    The lead isotopic compositions and uranium, thorium, and lead concentrations have been measured on six samples of material from the Sea of Tranquillity. The leads are moderately to very radiogenic; the initial lead concentrations are very low; the uranium and thorium levels are 0.26 to 0.88 and 0.87 to 3.35 parts per million, respectively. The Th/U ratios cluster about a 3.6 value. Apparent ages calculated for four rocks are 4.1 to 4.2 x 10(9) years. Dust and breccia yield apparent ages of 4.60 to 4.63 x 10(9) years. The uranium-lead ages are concordant, or nearly so, in all cases. The lunar surface is an ancient region with an extended record of events in the early history of the solar system. discrepancy between the rock ages and dust ages poses a fundamental qusestion about rock genesis on the moon.

  7. Adsorption of thorium cation on modified clays MTTZ derivative.

    PubMed

    Guerra, Denis L; Viana, Rúbia R; Airoldi, Claudio

    2009-09-15

    Diquite (D) and bentonite (B) mineral samples from the Amazon region, Brazil, were modified by MTTZ derivative (5-mercapto-1-methyltetrazole) using heterogeneous route. These materials were characterized by textural and elemental analysis, transmission electron microscopy (TEM), power X-ray diffraction and (13)C NMR spectroscopy. The chemically modified clay (D(MTTZ) and B(MTTZ)) samples showed modification of its physical-chemical properties including: specific area 41.4 (B) to 398.5m(2)g(-1) (B(MTTZ)) and 25.0 (D) to 178.8m(2)g(-1) (D(MTTZ)). The adsorption experiments performed under batch process with Th(IV) concentration, pH and contact time as variables. The ability of these materials to remove thorium from aqueous solution was followed by a series of adsorption isotherms adjusted to a Sips equation at room temperature and pH 2.0, with variable concentration of Th(IV). The maximum number of moles adsorbed was determined to be 10.45 x 10(-2) and 12.76 x 10(-2)mmol g(-1) for D(MTTZ) and B(MTTZ), respectively. The energetic effects (Delta(int)H degrees , Delta(int)G degrees and Delta(int)S degrees ) caused by thorium cation adsorption were determined through calorimetric titrations.

  8. Thorium resources of selected regions in the United States

    USGS Publications Warehouse

    Staatz, Mortimer Hay; Hall, R.B.; Macke, D.L.; Armbrustmacher, T.J.; Brownfield, I.K.

    1980-01-01

    Thorium resources have been assessed in a previous report entitled 'Principal thorium resources in the United States' (Staatz and others, 1979) for (1) veins in the larger districts, {2) massive carbonatites, {3) disseminated deposits, and {4) stream placers of North and South Carolina. This report is a sequel to that report and assesses thorium resources in {1) Florida beach placers, (2) Idaho stream placers, (3) veins and pipes in the Bokan Mountain district, Alaska, (4) carbonatite dikes, and {5) apatite-bearing iron deposits near Mineville, New York. Thorium resources for each of these categories are divided into reserves and probable potential resources. When data are available, each of these is then divided into the following cost categories: (1) the amount of ThO2 producible at a cost of less than $15/lb (per pound), (2) the amount producible at a cost of between $15 and $30/lb, and (3) the amount producible at a cost of between $30 and $50/1b. Beach placers of northern Florida have reserves of 16,200 short tons of ThO2 and probable potential resources of 5,120 tons of ThO2. These deposits are heavy-mineral placers that are mined for a variety of minerals--principally titanium minerals and zircon. The thorium-bearing mineral in these placers, monazite, makes up only a minor part of the heavy minerals. Therefore, production of ThO2 from these placers is dependent on the markets for other heavy minerals. Assuming the market for other heavy minerals to be the same as in 1978, then 98 percent of the ThO2 could be produced for less than $15/lb. If, however, no other coproducts were produced, then the cost of producing ThO2 would be greater than $50/1b. Stream placers containing thorium are found along many streams that drain the Idaho batholith, but most are too small to add significantly to the thorium resources. The resources of the five largest districts, each of which consists of at least several individual placers, have been tabulated. These districts are (1

  9. Toxicity of cerium and thorium on Daphnia magna.

    PubMed

    Ma, Yuhui; Wang, Jingkun; Peng, Can; Ding, Yayun; He, Xiao; Zhang, Peng; Li, Na; Lan, Tu; Wang, Dongqi; Zhang, Zhaohui; Sun, Fuhong; Liao, Haiqing; Zhang, Zhiyong

    2016-12-01

    Cerium (Ce) and thorium (Th) are always thought to be chemically similar and have comparable toxic properties on living organisms. In the present study, the acute and chronic toxicity of these two elements to freshwater crustacean Daphnia magna were investigated in the modified reconstituted water (6mg/L KCl, 123mg/L MgSO4·7H2O, and 294mg/L CaCl2·2H2O in Milli-Q water, pH 7.8). It seemed that Ce and Th had comparable acute toxicity on Daphnia: 24/48h EC50 for Th and Ce were 7.3/4.7μM and 16.4/10.7μM, respectively. However, Ce was present as soluble ions while all of Th was present as particulate ThO2 in the exposure medium. Considering their different chemical forms and bioavailability, the toxic mechanisms of Ce(3+) and ThO2 on Daphnia would be totally different. To our knowledge, this is the first time to investigate the aquatic toxicity of thorium and cerium based on their actual chemical speciation in the exposure medium. The results also suggest that more attention should be paid on the detrimental effect of Th in the form of particulate ThO2.

  10. Validating an important aspect of the new ICRP biokinetic model of thorium.

    PubMed

    Roth, P; Höllriegl, V; Li, W B; Oeh, U; Schramel, P

    2005-03-01

    The daily urinary excretion of Th (Th) was estimated in 11 adult German subjects who were not exposed occupationally to thorium and its related compounds. Thirty-one urine samples were collected over 24-h periods on different occasions from these subjects and were analyzed using high resolution sector field inductively coupled plasma mass spectrometry (HR-SF-ICP-MS). Using this instrument a limit of detection of 20 pg L for thorium in the reagent blank was achieved. The median (mean) daily urinary thorium excretion was obtained as 1.0 (1.8) ng. This was in good agreement with the mean value of 1.5 ng Th (6 microBq) reported by another group for German population, but is significantly lower in comparison to the daily excretion range of 3.6 to 105 ng reported from other countries. The expected daily urinary excretion of thorium for the adult German population was also calculated by applying the new ICRP biokinetic model of thorium assuming reference intake values. The expected urinary thorium excretion rate for this age group is about 0.1 ng per day. Even if a small contribution from the inhalation is considered, the calculated value will be much lower than the measured values. The reason for the disagreement appears to be the use of a low gastrointestinal absorption factor (f1) of 5 x 10 in the ICRP model. Based on the present study, a higher f1 factor might be proposed separately for dietary incorporated thorium.

  11. [Adsorption behavior of exogenous thorium on soil contaminated by rare earth industries].

    PubMed

    Guo, Peng-ran; Jia, Xiao-yu; Duan, Tai-cheng; Qiu, Rong-liang; Chen, Hang-ting

    2009-10-15

    The adsorption behavior of exogenous thorium on soil was studied to evaluate the contaminated risk on soil. The adsorption capacity, equilibrium time, distribution coefficient and desorption ability were investigated by the experiments of static adsorption. The strong adsorption ability of exogenous thorium on soil samples was observed by high adsorption ratio (> 92%) and low desorption ratio (< 5%) in equilibrium, and the biggest distribution coefficient was over 10(4). The adsorption capacity and equilibrium time were related to soil properties. According to the results of adsorption, Freundlich equation (r > or = 0.9167) and Elovich equation (R2 > or = 0.8980) were primely fit for describing the thermodynamics and kinetics of the adsorption of exogenous thorium on soil samples, respectively, which indicated that the adsorption was belonged to the nonlinear adsorption, and was affected by the diffusion of thorium on soil surface and in mineral interbed. Sequential extraction procedure was employed to evaluate the bound fractions of exogenous thorium adsorbed on soil samples. Based on the extracted results of thorium fractions, exogenous thorium was presented in the labile nonresidual fractions (over 58%) at the low initial concentration (10(-7) - 10(-6) mol x L(-1)), and nonresidual fractions enhanced with the increase of the initial amount, meanwhile more exogenous throium was transferred to the stable residual fractions.

  12. Advanced Burner Reactor with Breed-and-Burn Thorium Blankets for Improved Economics and Resource Utilization

    SciTech Connect

    Greenspan, Ehud

    2015-11-04

    fabrication capacity per unit of core power. Nevertheless, these high-performance cores were designed to set upper bounds on the S&B core performance by using larger height and pressure drop than those of typical SFR design. A study was subsequently undertaken to quantify the tradeoff between S&B core design variables and the core performance. This study concludes that a viable S&B core can be designed without significant deviation from SFR core design practices. For example, the S&B core with 120cm active height will be comparable in volume, HM mass and specific power with the S-PRISM core and could fit within the S-PRISM reactor vessel. 43% of this core power will be generated by the once-through thorium blanket; the required capacity for reprocessing and remote fuel fabrication per unit of electricity generated will be approximately one fifth of that for a comparable ABR. The sodium void worth of this 120cm tall S&B core is significantly less positive than that of the reference ABR and the Doppler coefficient is only slightly smaller even though the seed uses a fertile-free fuel. The seed in the high transmutation core requires inert matrix fuel (TRU-40Zr) that has been successfully irradiated by the Fuel Cycle Research & Development program. An additional sensitivity analysis was later conducted to remove the bias introduced by the discrepancy between radiation damage constraints -- 200 DPA applied for S&B cores and fast fluence of 4x1023 n(>0.1MeV)/cm2 applied for ABR core design. Although the performance characteristics of the S&B cores are sensitive to the radiation damage constraint applied, the S&B cores offer very significant performance improvements relative to the conventional ABR core design when using identical constraint.

  13. ORNL experience and perspectives related to processing of thorium and 233U for nuclear fuel

    DOE PAGES

    Croff, Allen G.; Collins, Emory D.; Del Cul, G. D.; ...

    2016-05-01

    Thorium-based nuclear fuel cycles have received renewed attention in both research and public circles since about the year 2000. Much of the attention has been focused on nuclear fission energy production that utilizes thorium as a fertile element for producing fissionable 233U for recycle in thermal reactors, fast reactors, or externally driven systems. Here, lesser attention has been paid to other fuel cycle operations that are necessary for implementation of a sustainable thorium-based fuel cycle such as reprocessing and fabrication of recycle fuels containing 233U.

  14. The Crystal Structure of Thorium and Zirconium Dihydrides by X-ray and Neutron Diffraction

    DOE R&D Accomplishments Database

    Rundle, R.E.; Shull, C.G.; Wollan, E.O.

    1951-04-20

    Thorium forms a tetragonal lower hydride of composition ThH{sub 2}. The hydrides ThH{sub 2}, ThD{sub 2}, and ZrD{sub 2} have been studied by neutron diffraction in order that hydrogen positions could be determined. The hydrides are isomorphous, and have a deformed fluorite structure. Metal-hydrogen distances in thorium hydride are unusually large, as in UH{sub 3}. Thorium and zirconium scattering amplitudes and a revised scattering amplitude for deuterium are reported.

  15. Thorium Deposits of the United States - Energy Resources for the Future?

    USGS Publications Warehouse

    Van Gosen, Bradley S.; Gillerman, Virginia S.; Armbrustmacher, Theodore J.

    2009-01-01

    Many nations are exploring new ways to meet their growing energy supply needs, with a particular focus upon methods that produce lower carbon dioxide emissions compared to traditional oil, natural gas, and coal power plants. As a result, thorium-based nuclear power has experienced renewed attention as a potential energy source. Thus, it benefits the United States and other countries to identify and evaluate their indigenous thorium resources. This report describes the geology and resources of the principal thorium districts of the United States.

  16. Uranium and thorium in urine of United States residents: Reference range concentrations

    SciTech Connect

    Ting, B.G.; Paschal, D.C.; Jarrett, J.M.; Pirkle, J.L.; Jackson, R.J.; Sampson, E.J.; Miller, D.T.; Caudill, S.P. )

    1999-07-01

    The authors measured uranium and thorium in urine of 500 US residents to establish reference range concentrations using a magnetic-sector inductively coupled argon plasma mass spectrometer (ICP-MS). They found uranium at detectable concentrations in 96.6% of the urine specimens and thorium in 39.6% of the specimens. The 95th percentile concentration for uranium was 34.5 ng/L (parts per trillion); concentrations ranged up to 4,080 ng/L. Thorium had a 95th percentile concentration of 3.09 ng/L; concentrations ranged up to 7.7 ng/L.

  17. Uranium and thorium in urine of United States residents: reference range concentrations.

    PubMed

    Ting, B G; Paschal, D C; Jarrett, J M; Pirkle, J L; Jackson, R J; Sampson, E J; Miller, D T; Caudill, S P

    1999-07-01

    We measured uranium and thorium in urine of 500 U. S. residents to establish reference range concentrations using a magnetic-sector inductively coupled argon plasma mass spectrometer (ICP-MS). We found uranium at detectable concentrations in 96.6% of the urine specimens and thorium in 39.6% of the specimens. The 95th percentile concenetration for uranium was 34.5 ng/L (parts per trillion); concentrations ranged up to 4080 ng/L. Thorium had a 95th percentile concentration of 3.09 ng/L; concentrations ranged up to 7.7 ng/L. Copyright 1999 Academic Press.

  18. Determination of thorium in environmental and workplace materials by ICP-MS.

    PubMed

    Holmes, L; Pilvio, R

    2000-01-01

    The paper outlines the advantages of the use of Inductively Coupled Plasma Mass Spectrometry (ICP-MS) over radiometric techniques to measure natural thorium, 232Th. Experimental parameters that must be taken into account in the sample digestion, preparation and ICP-MS analysis of environmental (soils, rocks, sediments) or workplace (thorium oxide, reference solutions) materials are described. The methods presented are applied to various reference materials, with the aim of providing suitable procedures to be useful for other important thorium containing materials (such as monazite sands or welding electrodes). The participation in a European Commission intercomparison exercise is detailed and a comparison with alpha spectrometry is made.

  19. A thorium isotope proxy for reconstructing dissolved detrital inputs to the ocean

    NASA Astrophysics Data System (ADS)

    McManus, J. F.; Robinson, L. F.; Noble, T. L.; Henderson, G. M.

    2006-12-01

    We have developed a tracer of dissolved detrital inputs to seawater based on thorium isotopes adsorbed from seawater onto settling marine particles. Thorium is extremely insoluble, yet occurs in all ocean waters in abundances that are measurable by ICP-MS mass spectrometry. Thorium-232 is derived exclusively from the partial dissolution of detritus, which in distal open-ocean settings is predominantly delivered through eolian transport. Thorium-230 is produced everywhere in the ocean at a well-constrained rate by the decay of dissolved uranium. The 232/230 ratio of adsorbed thorium, isolated from lattice-bound thorium, may be used to reconstruct the local water column thorium profiles, which are in turn controlled by dissolved detrital input. The water column reconstructions are independent of detrital accumulation records, including those captured in high latitude ice cores, and can thus be focused on relevant regions of the ocean. This new tracer may be used to evaluate a variety of scenarios regarding the ocean and atmosphere of the past, including dust fertilization schemes that link variations in paleo-productivity with changes in atmospheric carbon dioxide and global climate. The half-lives of both thorium isotopes are long enough to allow us to use our approach on sediments that span several glacial-interglacial cycles. Initial investigations indicate that we are successful in isolating the adsorbed (seawater) thorium using a range of progressively vigorous chemical leaching steps with variable yield, but constant isotopic ratio. Recent sediments from a N-S transect of the Southern Ocean, the subpolar North Pacific, the subtropical North Atlantic, and the tropical Atlantic yield thorium ratios that are similar to nearby water column profiles. Preliminary downcore results display higher thorium 232/230 ratios that are consistent with enhanced ice-age dust deposition. However the two- to four-fold glacial increases indicated by the thorium isotope proxy are

  20. Evaluation of in vitro dissolution rates of thorium in uranium mill tailings.

    PubMed

    Reif, R H

    1994-11-01

    Dissolution rates of thorium from the uranium mill tailings piles at two Department of Energy Uranium Mill Tailings Remedial Action Project (UMTRAP) sites have been evaluated. The thorium dissolution rates were evaluated in vitro using simulated lung fluid. The former uranium mills at the UMTRAP sites employed different chemical processes (acid leach and alkaline pressure leach) to extract the uranium from the ore, and the thorium dissolution rates at these sites were found to be markedly different. A site specific annual limit on intake (ALI) value for 230Th was calculated for the UMTRAP site that was associated with a multiple component dissolution curve.

  1. Thorium determination in intercomparison samples and in some Romanian building materials by gamma ray spectrometry.

    PubMed

    Pantelica, A; Georgescu, I I; Murariu-Magureanu, M D; Margaritescu, I; Cincu, E

    2001-01-01

    Thorium content in zircon sand, thorium ore and a thorium liquid sample (EU Laboratories Network Intercomparison), as well as in some Romanian building materials: sand, wood, tufa, asbestos-cement. cement mill dust, coal fly ash, bricks, and tile (28 samples) was deterimined by gamma ray spectrometry. For the building materials, 226Ra, 40K and 137Cs specific activities were also measured. The results were compared with the Romanian legal norms concerning the highest admissible levels for 232Th, 226Ra. and 40K radioactivity. and to Th, U, and K concentration values previously determined in our laboratory on similar types of samples.

  2. Relativistic small-core pseudopotentials for actinium, thorium, and protactinium.

    PubMed

    Weigand, Anna; Cao, Xiaoyan; Hangele, Tim; Dolg, Michael

    2014-04-03

    Small-core pseudopotentials for actinium, thorium, and protactinium have been energy-adjusted to multiconfiguration Dirac-Hartree-Fock reference data based on the Dirac-Coulomb-Breit Hamiltonian and the Fermi nucleus model. Corresponding optimized valence basis sets of polarized valence quadruple-ζ quality are presented. Atomic test calculations for the first four ionization potentials show satisfactory results at both the Hartree-Fock and the multireference averaged coupled-pair functional level. Highly correlated Fock-space coupled cluster calculations demonstrate that the new pseudopotentials yield ionization potentials, which are in excellent agreement with corresponding all-electron results and experimental data. The pseudopotentials and basis sets supplement a similar set previously published for uranium.

  3. Feasibility study on the thorium fueled boiling water breeder reactor

    SciTech Connect

    PetrusTakaki, N.

    2012-07-01

    The feasibility of (Th,U)O 2 fueled, boiling water breeder reactor based on conventional BWR technology has been studied. In order to determine the potential use of water cooled thorium reactor as a competitive breeder, this study evaluated criticality, breeding and void reactivity coefficient in response to changes made in MFR and fissile enrichments. The result of the study shows that while using light water as moderator, low moderator to fuel volume ratio (MFR=0.5), it was possible to breed fissile fuel in negative void reactivity condition. However the burnup value was lower than the value of the current LWR. On the other hand, heavy water cooled reactor shows relatively wider feasible breeding region, which lead into possibility of designing a core having better neutronic and economic performance than light water with negative void reactivity coefficient. (authors)

  4. Protactinium-thorium ratio as a proxy for ocean circulation

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2011-12-01

    The Atlantic meridional overturning circulation (AMOC) transports water and heat over long distances in the Atlantic Ocean and is believed to have an important effect on Earth's climate. Knowing how strong the AMOC was in the past is essential to understanding past climate. One proxy researchers have used to assess the past strength of the AMOC is the sedimentary protactinium- thorium ratio (231Pa/230Th). Both 231Pa and 230Th are produced through decay of uranium at a constant rate in the ocean water column, but 230Th does not last long enough in the water to be transported away from the location where it was produced, while 231Pa has a longer residence time in the water. Therefore, sedimentary 231Pa/230Th ratios could provide information about the strength of past ocean circulation.

  5. Insights into Particle Cycling from Thorium and Particle Data

    NASA Astrophysics Data System (ADS)

    Lam, Phoebe J.; Marchal, Olivier

    2015-01-01

    Marine particles are a main vector by which the biological carbon pump in the ocean transfers carbon from the atmosphere to the deep ocean. Marine particles exist in a continuous spectrum of sizes, but they can be functionally grouped into a small, suspended class (which constitutes most of the total particle mass) and a large, sinking class (which contributes most of the particle flux). These two classes are connected by aggregation and disaggregation processes. The interplay of processes that create, aggregate, and destroy marine particles determines the strength and transfer efficiency of the biological pump. Measurements of radiocarbon, barium, and organic biomarkers on suspended and sinking particles have provided qualitative insights into particle dynamics, and measurements of thorium isotopes have provided quantitative estimates of rates. Here, we review what has been learned so far about particle dynamics in the ocean from chemical measurements on suspended and sinking particles. We then discuss future directions for this approach.

  6. Ab-initio calculations on melting of thorium

    SciTech Connect

    Mukherjee, D. Sahoo, B. D.; Joshi, K. D.; Kaushik, T. C.; Gupta, Satish C.

    2016-05-23

    Ab-initio molecular dynamics study has been performed on face centered cubic structured thorium to determine its melting temperature at room pressure. The ion-electron interaction potential energy calculated as a function of temperature for three volumes (a{sub 0}){sup 3} and (1.02a{sub 0}){sup 3} and (1.04a{sub 0}){sup 3} increases gradually with temperature and undergoes a sharp jump at ~2200 K, ~2100 K and ~1800 K, respectively. Here, a{sub 0} = 5.043 Å is the equilibrium lattice parameter at 0 K obtained from ab-initio calculations. These jumps in interaction energy are treated as due to the onset of melting and corresponding temperatures as melting point. The melting point of 2100 K is close to the experimental value of 2023 K. Further, the same has been verified by plotting the atomic arrangement evolved at various temperatures and corresponding pair correlation functions.

  7. Uptake of uranium and thorium by native and cultivated plants.

    PubMed

    Shtangeeva, I

    2010-06-01

    Large part of available literature on biogeochemistry of uranium and thorium refers to the studies performed either in highly contaminated areas or in nutrient solutions that have been artificially 'spiked' with radionuclides. Effects of background levels of natural radioactivity on soil-grown plants have not been studied to the same extent. In this paper, we summarised results of greenhouse and field experiments performed by the author from 2000 to 2006. We examined some of the factors affecting transfer of U and Th from soil to plants, differences in uptake of these radionuclides by different plants, relationships between U and Th in soil and in plants, and temporal variations of U and Th in different plant species. Concentrations of radionuclides (critical point for experimental studies on biogeochemistry of U and Th--rare trace elements in non-contaminated regions) and essential plant nutrients and trace elements were determined by instrumental neutron activation analysis. Copyright (c) 2008 Elsevier Ltd. All rights reserved.

  8. L-subshell fluorescence yields for metallic uranium and thorium

    NASA Astrophysics Data System (ADS)

    Xu, J. Q.; Xu, X. J.

    1995-03-01

    The L x-ray spectra induced by ~50-keV electron impact on metallic targets of uranium and thorium have been analyzed and the relative fluorescence yields of the L1, L2, and L3 subshell of the two elements, ω2/ω3 and ω1/ω3, have been derived. The present values of ω2/ω3 and ω2 are notably different from the latest theoretical calculations and semiempirically compiled data, and also from the previous measurements using radionuclide decays to produce initial inner vacancies in the atoms. However, they are reasonable for the theoretical computation of U L x-ray relative intensities induced by a few-MeV proton bombardment on metallic uranium. The deviation is discussed and attributed mainly to an enhancement of the total relaxation effect and the shakeup process in metals with respect to those in the corresponding atomic systems as well as in the chemical compounds.

  9. Thorium investigations, 1950-52, Wet Mountains, Colorado

    USGS Publications Warehouse

    Christman, R.A.; Heyman, A.M.; Dellwig, L.F.; Gott, G.B.

    1953-01-01

    active mineral It is associated with barite: quartz, galena, fluorite, limonite, and pyrite Some of the shear zones perhaps can be traced for as much as 2 miles, but the largest known thorium-bearing ore body is as much as 300 feet long, 26 feet wide, and 400 feet deep. Samples from the veins contain as much as 1.6 percent equivalent Th02 Eleven diamond drill holes, totaling 3,292.4 feet have explored five shear zones on the Haputa Ranch. Three ore bodies of possible economic interest are indicated in two interconnecting shear zones. No other deposits in the wet Mountains have been explored, or even sampled adequately to hazard an estimate as to grade and tonnage of reserves.

  10. Mortality among female workers at a thorium-processing plant

    SciTech Connect

    Liu, Zhiyuan; Lee, Tze-San

    1994-05-01

    The mortality patterns among a cohort of 677 female workers at a thorium-processing plant are reported for the period from 1940 to 1982. Of the 677 women, 165 were reported dead; 459 were still alive; and 53 (7.8%) were lost to follow-up. The standardized mortality ratios from all causes (0.74), all cancers (0.53), and circulatory diseases (0.66) were significantly below those for the general US population. In this cohort, 5 deaths due to lung cancer and 1 death from leukemia were observed, with 4.53 and 1.69 deaths expected, respectively. No deaths from cancer of the liver, pancreas, or bone were observed. Poisson regression analysis was used for an internal comparison within the cohort. The results of the Poisson regression analysis showed no significant effect on mortality rates of all causes and cancers from the study factors, including job classification, duration of employment, and time since first employment.

  11. Fabrication of very high density fuel pellets of thorium dioxide

    NASA Astrophysics Data System (ADS)

    Shiratori, Tetsuo; Fukuda, Kosaku

    1993-06-01

    Very high density ThO 2 pellets were prepared without binders and lubricants from the ThO 2 powder originated by the thorium oxalate, which was aimed to simplify the fabrication process by skipping a preheat treatment. The as-received ThO 2 powder with a surface area of 4.56 m 2/g was ball-milled up to about 9 m 2/g in order to increase the green pellet density as high as possible. Both of the single-sided and the double-sided pressing were tested in the range from 2 to 5 t/cm 2 in the green pellet formation. Sintering temperature was such low as 1550°C. The pellet prepared in this experiment had a very high density in the range from about 96 to 98% TD without any cracks, in which a difference of the pellet density was not recognized in the single-sided pressing methods.

  12. Multiply charged thorium ions for nuclear laser spectroscopy

    NASA Astrophysics Data System (ADS)

    Depalatis, Michael V.; Campbell, Corey J.; Churchill, Layne R.; Naylor, Dave E.; Radnaev, Alexander; Chapman, Michael S.; Kuzmich, Alex

    2010-03-01

    Coherent excitation of the electronic states of atoms and molecules with lasers is at the heart of modern spectroscopy and metrology. To extend these techniques to nuclear states would be a tremendous advance. However, the typical excitation energies for nuclear matter are in the keV to MeV energy range, out of reach of modern coherent radiation sources. In the unique case of the ^229Th nucleus, the energy splitting of the ground state doublet is only several eV,ootnotetextL. A. Kroger & C. W. Reich, Nucl. Phys. A 259, 29 (1976). which may be within the reach of coherent table-top UV lasers. Previously we demonstrated the direct laser cooling of ^232Th^3+ in an rf Paul trap,ootnotetextC. J. Campbell et al., Phys. Rev. Lett 102, 233004 (2009). an important first step towards nuclear laser spectroscopy. Here we report progress towards loading and trapping ^229Th^3+ from a Thorium nitrate source.

  13. Stability of a new cubic monoxide of Thorium under pressure

    PubMed Central

    Sun, Weiwei; Luo, Wei; Ahuja, Rajeev

    2015-01-01

    Density functional theory has been applied to elucidate the stability of thorium monoxide (ThO). It is found out that the pressure can stabilize the rocksalt phase of ThO, and the transition pressure is estimated between 14 and 22 GPa. The stability of ThO can be attributed due to the gradually filling 5f orbitals at the expense of 7s and 6d electrons in Th metal. For ThO, the pressure induces stronger Th-O bond reflected by the newly established 6d-2p hybridization which is the dominant cause of its stability. The phonon dispersion curves of the rocksalt phase show the positive frequencies which indicates its dynamical stability. Our successful prediction of the stabilization of the metallic ThO has proposed a route to synthesize novel actinide monoxides. PMID:26337015

  14. Insights into particle cycling from thorium and particle data.

    PubMed

    Lam, Phoebe J; Marchal, Olivier

    2015-01-01

    Marine particles are a main vector by which the biological carbon pump in the ocean transfers carbon from the atmosphere to the deep ocean. Marine particles exist in a continuous spectrum of sizes, but they can be functionally grouped into a small, suspended class (which constitutes most of the total particle mass) and a large, sinking class (which contributes most of the particle flux). These two classes are connected by aggregation and disaggregation processes. The interplay of processes that create, aggregate, and destroy marine particles determines the strength and transfer efficiency of the biological pump. Measurements of radiocarbon, barium, and organic biomarkers on suspended and sinking particles have provided qualitative insights into particle dynamics, and measurements of thorium isotopes have provided quantitative estimates of rates. Here, we review what has been learned so far about particle dynamics in the ocean from chemical measurements on suspended and sinking particles. We then discuss future directions for this approach.

  15. Nuclear thermionic converter. [tungsten-thorium oxide rods

    NASA Technical Reports Server (NTRS)

    Phillips, W. M.; Mondt, J. F. (Inventor)

    1977-01-01

    Efficient nuclear reactor thermionic converter units are described which can be constructed at low cost and assembled in a reactor which requires a minimum of fuel. Each converter unit utilizes an emitter rod with a fluted exterior, several fuel passages located in the bulges that are formed in the rod between the flutes, and a collector receiving passage formed through the center of the rod. An array of rods is closely packed in an interfitting arrangement, with the bulges of the rods received in the recesses formed between the bulges of other rods, thereby closely packing the nuclear fuel. The rods are constructed of a mixture of tungsten and thorium oxide to provide high power output, high efficiency, high strength, and good machinability.

  16. The thoron-tartaric acid systems for the spectrophotometric determination of thorium

    USGS Publications Warehouse

    Grimaldi, F.S.; Fletcher, Mary H.

    1955-01-01

    Thoron is popularly used for the spectrophotometric determination of thorium.  An undesirable feature of its use is the high sensitivity of the reagent toward zirconium. This study describes the use of tartaric acid as a masking reagent for zirconium. Three tartaric acid-thoron systems, developed for the determination of thorium, differ with respect to the concentrations of thoron and tartaric acid. Mesotataric acid, used in one of the systems, is found to be most effective in masking zirconium. The behavior of various rarer elements, usually found associated with thorium ores, is determined in two of the systems, and a dilution method is described for the direct determination of thorium in monazite concentrates.

  17. Recovery of protactinium-231 and thorium-230 from cotter concentrate: pilot plant operatins and process development

    SciTech Connect

    Hertz, M.R.; Figgins, P.E.; Deal, W.R.

    1983-02-10

    The equipment and methods used to recover and purify 339 g of thorium-230 and 890 mg of protactinium-231 from 22 of the 1251 drums of Cotter Concentrate are described. The process developed was (1) dissolution at 100/sup 0/C in concentrated nitric acid and dilution to 2 to 3 molar acid, (2) filtration to remove undissolved solids (mostly silica filter aid), (3) extraction of uranium with di-sec-butyl-phenyl phophonate (DSBPP) in carbon tetrachloride, (4) extraction of both thorium and protactinium with tri-n-octylphosphine oxide (TOPO) in carbon tetrachloride followed by selective stripping of the thorium with dilute of sulfuric acid, (5) thorium purification using oxalic acid, (6) stripping protactinium from the TOPO with oxalic acid, and (7) protactinium purification through a sequence of steps. The development of the separation procedures, the design of the pilot plant, and the operating procedures are described in detail. Analytical procedures are given in an appendix. 8 figures, 4 tables.

  18. The distribution of uranium and thorium in samples taken from different polluted marine environment.

    PubMed

    Akyil, S; Yusof, A M

    2007-06-01

    Concentrations of uranium and thorium in seawater, sediment and some marine species taken from along the coastal areas of Malaysia were determined spectrophotometrically. The uranium and thorium concentrations in seawater were found to vary ranging from 1.80 to 4.1 and 0.14 to 0.88 microg/L, respectively. The concentration of uranium in sediment samples was reported to range from 3.00 to 6.60 microg/g while those of thorium were slightly lower ranging from 0.01 to 0.68 microg/g. The uptake of uranium and thorium in marine species was found to be rather low. Similar variations in total alpha activities in samples were also observed with the total alpha activities relatively lower than the beta activities in most samples.

  19. The role of chemical interactions between thorium, cerium, and lanthanum in lymphocyte toxicity.

    PubMed

    Oliveira, Monica S; Duarte, Isabelle M; Paiva, Amanda V; Yunes, Samira N; Almeida, Carlos E; Mattos, Rita C; Sarcinelli, Paula N

    2014-01-01

    Thorium, cerium, and lanthanum are metals present in several types of minerals, the most common of which is monazite. Cerium and lanthanum are elements in the lanthanides series. Thorium, an actinide metal, is a hazardous element due to its radioactive characteristics. There is a lack of information describing the possible chemical interactions among these elements and the effects they may have on humans. Toxicological analyses were performed using cell viability, cell death, and DNA damage assays. Chemical interactions were evaluated based on the Loewe additivity model. The results indicate that thorium and cerium individually have no toxic effects on lymphocytes. However, thorium associated with lanthanum increases the toxicity of this element, thereby reducing the viability of lymphocytes at low concentrations of metals in the mixture.

  20. Thorium-induced neurobehavioural and neurochemical alterations in Swiss mice.

    PubMed

    Kumar, Amit; Ali, Manjoor; Mishra, Pravin; Pandey, B N; Sharma, Pragya; Mishra, Kaushala Prasad

    2009-04-01

    Thorium ((232)Th), a heavy metal radionuclide that targets the liver and skeleton, has been shown to accumulate in the central nervous system at low levels. The present study was aimed to investigate neurobehavioural and neurochemical changes in mice treated with (232)Th at sub-lethal doses. Swiss albino mice were administered intraperitoneally with thorium nitrate. The chelation-based therapeutic effect of calcium diethylenetriamine pentaacetate (Ca-DTPA) was tested on the (232)Th-treated mice. (232)Th localisation was determined in brain regions by the Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) method. Achetylcholine esterase (AChE) activity in different brain regions was evaluated to assess the cholinergic function of mice CNS. Oxidative damage was evaluated by assessing the activities of antioxidant enzymes (i.e., superoxide dismutase and catalase) and the level of lipid peroxidation. The neurobehavioural alteration in the treated mice was studied by the shuttle box method. (232)Th accumulation found in different brain regions followed the order: Cerebellum (Cbl) > cortex (Ctx) > hippocampus (Hp) > striatum (Str). However, removal of (232)Th by Ca-DTPA was significant from brain regions like Cbl, Ctx and Str but not from Hp. A significant increase in lipid peroxidation and acetylcholine esterase (AChE) activity was observed in the treated mice but activities of superoxide dismutase and catalase was found substantially decreased. (232)Th treatment impaired the learning and memory-based neurobehaviour of the mice. Furthermore, our data suggest that Ca-DTPA injection in (232)Th-treated animals failed to improve the neurobehaviour of the treated mice, perhaps because Ca-DTPA could not decorporate (232)Th or mitigate (232)Th-mediated neurochemical changes effectively from/in hippocampus, a brain region implicated in learning and memory response. Administration of (232)Th in mice caused neurobehavioural alteration and impairment of cholinergic

  1. Thorium-Based Transmuter Fuels for Light Water Reactors

    SciTech Connect

    J. Stephen Herring; P. E. MacDonald; K. Weaver

    2004-04-01

    A light water reactor (LWR) fuel cycle is proposed where the reactor core mainly consists of standard uranium-dioxide (UO2) fuel rods with typical 235U enrichment, along with thoria-urania (ThO2-UO2) or yttria-stablized zirconia fertile-free fuel rods containing the plutonium and minor actinides typical of 30-yr old UO2 fuel in 1/9 to 1/3 of the positions. The goals of this mono-recycling strategy or "twice through fuel cycle" are to transmute the great majority of the long lived actinides in existing LWRs and to discharge a fuel form that is a very robust waste form and whose isotopic content is very proliferation resistant. The incorporation of plutonium into a ThO2 or yttria-stablized zirconia fertile-free matrix results in the consumption of already-separated plutonium without breeding significant additional 239Pu. The minor actinides (i.e., neptunium, americium, curium, berkelium, californium, etc.) are also included in the ThO2 or fertile-free transmuter fuel rods to further reduce the overall long-term radiotoxicity of the fuel cycle. Our analyses have shown that thorium-based or fertile-free fuels can reduce the amount of 239Pu needing further transmutation or going to a repository by ~90%. Also, thorium-based fuels produce a mixture of plutonium isotopes high in 238Pu. Because of the high decay heat and spontaneous neutron generation of 238Pu, this isotope provides intrinsic proliferation resistance.

  2. Thorium-Based Transmuter Fuels for Light Water Reactors

    SciTech Connect

    Herring, J. Stephen; MacDonald, Philip E.; Weaver, Kevan D.

    2004-07-15

    A light water reactor (LWR) fuel cycle is proposed where the reactor core mainly consists of standard uranium-dioxide (UO{sub 2}) fuel rods with typical {sup 235}U enrichment, along with thoria-urania (ThO{sub 2}-UO{sub 2}) or yttria-stablized zirconia fertile-free fuel rods containing the plutonium and minor actinides typical of 30-yr old UO{sub 2} fuel in 1/9 to 1/3 of the positions. The goals of this mono-recycling strategy or 'twice through fuel cycle' are to transmute the great majority of the long lived actinides in existing LWRs and to discharge a fuel form that is a very robust waste form and whose isotopic content is very proliferation resistant. The incorporation of plutonium into a ThO{sub 2} or yttria-stablized zirconia fertile-free matrix results in the consumption of already-separated plutonium without breeding significant additional {sup 239}Pu. The minor actinides (i.e., neptunium, americium, curium, berkelium, californium, etc.) are also included in the ThO{sub 2} or fertile-free transmuter fuel rods to further reduce the overall long-term radiotoxicity of the fuel cycle. Our analyses have shown that thorium-based or fertile-free fuels can reduce the amount of {sup 239}Pu needing further transmutation or going to a repository by {approx}90%. Also, thorium-based fuels produce a mixture of plutonium isotopes high in {sup 238}Pu. Because of the high decay heat and spontaneous neutron generation of {sup 238}Pu, this isotope provides intrinsic proliferation resistance.

  3. The Growth of Monoraphidium sp. and Scenedesmus sp. Cells in the Presence of Thorium

    PubMed Central

    de Queiroz, Juliana Cristina; Ferreira, Ana Cristina de Melo; da Costa, Antonio Carlos Augusto

    2012-01-01

    Toxicity of thorium by Monoraphidium sp. and Scenedesmus sp. was studied. Microalgal cultures were inoculated in ASM-1 medium in presence and absence of thorium. Its effect was monitored by direct counting on Fuchs-Rosenthal chamber and with software. The toxicity of thorium over the species was observed for concentrations over 50.0 mg/L. After 30 days, Monoraphidium cells decreased their concentration from 4.23 × 106 to 4.27 × 105 and 8.57 × 105 cells/mL, in the presence of 50.0 and 100.0 mg/L of thorium, respectively. Scenedesmus sp. cells were more resistant to thorium: for an initial cell concentration of 7.65 × 104 cells/mL it was observed a change to 5.25 × 105 and 5.12 × 105 cells/mL, in the presence of thorium at 50.0 and 100.0 mg/L, respectively. This is an indication that low concentrations of the radionuclide favored the growth, and that Scenedesmus cells are more resistant to thorium than Monoraphidium cells. The software used for comparison with direct count method proved to be useful for the improvement of accuracy of the results obtained, a decrease in the uncertainty and allowed recording of the data. The presence of thorium suggests that low concentrations have a positive effect on the growth, due to the presence of the nitrate, indicating its potential for ecotoxicological studies. PMID:22649297

  4. Uranium and thorium distribution in soils and weathered bedrock in south Texas

    USGS Publications Warehouse

    Dickinson, Kendell A.

    1977-01-01

    The distribution of uranium and thorium in soils and weathered bedrock in areas of calich soil development on various kinds of sedimentary bedrock in south Texas indicates that uranium and thorium are leached from the surface layers and deposited deeper in the soil or weathered bedrock. The data provide field evidence that uranium is mobilized during dry-climate weathering, and suggest that caution be used in the interpretation of airborne, radioactive surveys that measure uranium at the surface.

  5. Correlation, relativistic, and quantum electrodynamics effects on the atomic structure of eka-thorium

    SciTech Connect

    Gaigalas, Gediminas; Gaidamauskas, Erikas; Rudzikas, Zenonas; Magnani, Nicola; Caciuffo, Roberto

    2010-02-15

    Large-scale multiconfiguration Dirac-Fock calculations have been performed for the superheavy element eka-thorium, Z=122. The resulting atomic structure is compared with that obtained by various computational approaches involving different degrees of approximation in order to elucidate the role that correlation, relativistic, Breit, and quantum electrodynamics corrections play in determining the low-energy atomic spectrum. The accuracy of the calculations is assessed by comparing theoretical results obtained for thorium with available experimental data.

  6. Studies on extraction of thorium from nitrate solutions with quaternary ammonium halides.

    PubMed

    El-Yamani, I S; Shabana, E I

    1984-08-01

    Thorium can be quantitatively extracted with 0.1 M Hyamine 1622 in dichloroethane from 0.25M nitric acid/2M sodium nitrate and stripped from the organic phase with 0.1M sulphuric acid. The equilibration takes 20 min. Thorium can thus be separated from a large number of elements which are usually associated with it in monazite and in fission products of nuclear fuel.

  7. Generation of thorium ions by laser ablation and inductively coupled plasma techniques for optical nuclear spectroscopy

    NASA Astrophysics Data System (ADS)

    Troyan, V. I.; Borisyuk, P. V.; Khalitov, R. R.; Krasavin, A. V.; Lebedinskii, Yu Yu; Palchikov, V. G.; Poteshin, S. S.; Sysoev, A. A.; Yakovlev, V. P.

    2013-10-01

    Single- and double-charged 232Th and 229Th ions were produced by laser ablation of solid-state thorium compounds and by inductively coupled plasma techniques with mass-spectrometry analysis from liquid solutions of thorium. The latter method was found to be more applicable for producing ions of radioactive 229Th for laser experiments when searching for the energy value of the isomeric nuclear transition.

  8. Fluorescent BINOL-based sensor for thorium recognition and a density functional theory investigation.

    PubMed

    Wen, Jun; Dong, Liang; Tian, Jie; Jiang, Tao; Yang, Yan-Qiu; Huang, Zeng; Yu, Xiao-Qi; Hu, Chang-Wei; Hu, Sheng; Yang, Tong-Zai; Wang, Xiao-Lin

    2013-12-15

    A novel 1,1'-bi-2-naphthol (BINOL) derivative fluorescence sensor L-1 for the recognition of thorium ion with a fluorescence quench response. This ligand showed high selectivity and sensitivity for thorium ion recognition. Coordination effects were investigated by DFT calculations, and the coordination modes and sites were confirmed. Moreover, the coordination abilities of the L-1 ligand with Th(4+) and UO2(2+) were evaluated.

  9. The growth of Monoraphidium sp. and Scenedesmus sp. cells in the presence of thorium.

    PubMed

    de Queiroz, Juliana Cristina; Ferreira, Ana Cristina de Melo; da Costa, Antonio Carlos Augusto

    2012-01-01

    Toxicity of thorium by Monoraphidium sp. and Scenedesmus sp. was studied. Microalgal cultures were inoculated in ASM-1 medium in presence and absence of thorium. Its effect was monitored by direct counting on Fuchs-Rosenthal chamber and with software. The toxicity of thorium over the species was observed for concentrations over 50.0 mg/L. After 30 days, Monoraphidium cells decreased their concentration from 4.23 × 10(6) to 4.27 × 10(5) and 8.57 × 10(5) cells/mL, in the presence of 50.0 and 100.0 mg/L of thorium, respectively. Scenedesmus sp. cells were more resistant to thorium: for an initial cell concentration of 7.65 × 10(4) cells/mL it was observed a change to 5.25 × 10(5) and 5.12 × 10(5) cells/mL, in the presence of thorium at 50.0 and 100.0 mg/L, respectively. This is an indication that low concentrations of the radionuclide favored the growth, and that Scenedesmus cells are more resistant to thorium than Monoraphidium cells. The software used for comparison with direct count method proved to be useful for the improvement of accuracy of the results obtained, a decrease in the uncertainty and allowed recording of the data. The presence of thorium suggests that low concentrations have a positive effect on the growth, due to the presence of the nitrate, indicating its potential for ecotoxicological studies.

  10. METHOD OF PREPARING URANIUM, THORIUM, OR PLUTONIUM OXIDES IN LIQUID BISMUTH

    DOEpatents

    Davidson, J.K.; Robb, W.L.; Salmon, O.N.

    1960-11-22

    A method is given for forming compositions, as well as the compositions themselves, employing uranium hydride in a liquid bismuth composition to increase the solubility of uranium, plutonium and thorium oxides in the liquid bismuth. The finely divided oxide of uranium, plutonium. or thorium is mixed with the liquid bismuth and uranium hydride, the hydride being present in an amount equal to about 3 at. %, heated to about 5OO deg C, agitated and thereafter cooled and excess resultant hydrogen removed therefrom.

  11. Thorium-based mixed oxide fuel in a pressurized water reactor: A feasibility analysis with MCNP

    NASA Astrophysics Data System (ADS)

    Tucker, Lucas Powelson

    This dissertation investigates techniques for spent fuel monitoring, and assesses the feasibility of using a thorium-based mixed oxide fuel in a conventional pressurized water reactor for plutonium disposition. Both non-paralyzing and paralyzing dead-time calculations were performed for the Portable Spectroscopic Fast Neutron Probe (N-Probe), which can be used for spent fuel interrogation. Also, a Canberra 3He neutron detector's dead-time was estimated using a combination of subcritical assembly measurements and MCNP simulations. Next, a multitude of fission products were identified as candidates for burnup and spent fuel analysis of irradiated mixed oxide fuel. The best isotopes for these applications were identified by investigating half-life, photon energy, fission yield, branching ratios, production modes, thermal neutron absorption cross section and fuel matrix diffusivity. 132I and 97Nb were identified as good candidates for MOX fuel on-line burnup analysis. In the second, and most important, part of this work, the feasibility of utilizing ThMOX fuel in a pressurized water reactor (PWR) was first examined under steady-state, beginning of life conditions. Using a three-dimensional MCNP model of a Westinghouse-type 17x17 PWR, several fuel compositions and configurations of a one-third ThMOX core were compared to a 100% UO2 core. A blanket-type arrangement of 5.5 wt% PuO2 was determined to be the best candidate for further analysis. Next, the safety of the ThMOX configuration was evaluated through three cycles of burnup at several using the following metrics: axial and radial nuclear hot channel factors, moderator and fuel temperature coefficients, delayed neutron fraction, and shutdown margin. Additionally, the performance of the ThMOX configuration was assessed by tracking cycle length, plutonium destroyed, and fission product poison concentration.

  12. Thorium-phosphorus triamidoamine complexes containing Th-P single- and multiple-bond interactions

    NASA Astrophysics Data System (ADS)

    Wildman, Elizabeth P.; Balázs, Gábor; Wooles, Ashley J.; Scheer, Manfred; Liddle, Stephen T.

    2016-09-01

    Despite the burgeoning field of uranium-ligand multiple bonds, analogous complexes involving other actinides remain scarce. For thorium, under ambient conditions only a few multiple bonds to carbon, nitrogen, oxygen, sulfur, selenium and tellurium are reported, and no multiple bonds to phosphorus are known, reflecting a general paucity of synthetic methodologies and also problems associated with stabilising these linkages at the large thorium ion. Here we report structurally authenticated examples of a parent thorium(IV)-phosphanide (Th-PH2), a terminal thorium(IV)-phosphinidene (Th=PH), a parent dithorium(IV)-phosphinidiide (Th-P(H)-Th) and a discrete actinide-phosphido complex under ambient conditions (Th=P=Th). Although thorium is traditionally considered to have dominant 6d-orbital contributions to its bonding, contrasting to majority 5f-orbital character for uranium, computational analyses suggests that the bonding of thorium can be more nuanced, in terms of 5f- versus 6d-orbital composition and also significant involvement of the 7s-orbital and how this affects the balance of 5f- versus 6d-orbital bonding character.

  13. An optical chemical sensor for thorium (IV) determination based on thorin.

    PubMed

    Rastegarzadeh, S; Pourreza, N; Saeedi, I

    2010-01-15

    A selective method for the determination of thorium (IV) using an optical sensor is described. The sensing membrane is prepared by immobilization of thorin-methyltrioctylammonium ion pair on triacetylcellulose polymer. The sensor produced a linear response for thorium (IV) concentration in the range of 6.46 x 10(-6) to 9.91 x 10(-5)mol L(-1) with detection limit of 1.85 x 10(-6)mol L(-1). The regeneration of optode was accomplished completely at a short time (less than 20s) with 0.1 mol L(-1) of oxalate ion solution. The relative standard deviation for ten replicate measurements of 2.15 x 10(-5) and 8.62 x 10(-5)mol L(-1) of thorium was 2.71 and 1.65%, respectively. The optode membrane exhibits good selectivity for thorium (IV) over several other ionic species and are comparable to those obtained in case of spectrophotometric determination of thorium using thorin in solution. A good agreement with the ICP-MS and spiked method was achieved when the proposed optode was applied to the determination of thorium (IV) in dust and water samples.

  14. Observation of changes in urinary excretion of thorium in humans following ingestion of a therapeutic soil.

    PubMed

    Höllriegl, V; Greiter, M; Giussani, A; Gerstmann, U; Michalke, B; Roth, P; Oeh, U

    2007-01-01

    The study investigated the changes in urinary thorium excretion by humans following ingestion of a therapeutic soil, which contains about 10 ppm of thorium. This well-known healing earth in Germany has been considered as an alternative medicine for diarrhoea and gastric hyper-acidity. Six adult volunteers ingested this therapeutic soil in varying quantities for 1-15 days at levels approximating those described in the package insert of the medicine (10-60 g of soil per day). The subjects ingested about 0.1-0.6 mg of thorium daily, which is 100-600 times higher than the normal daily intake of about 1 microg thorium in Germany. All 24-h urine samples collected from the subjects during pre-ingestion, ingestion and post-ingestion periods of the soil were analyzed for (232)Th using inductively coupled plasma mass spectrometry (ICP-MS). The measured excretion values varied in a wide range. Apparently, the high thorium amounts administered did not increase the (232)Th excretion in urine as expected, suggesting that this soil ingestion will not result in a considerably higher and harmful uptake of thorium into the human body.

  15. Determination of thorium and of rare earth elements in cerium earth minerals and ores

    USGS Publications Warehouse

    Carron, M.K.; Skinner, D.L.; Stevens, R.E.

    1955-01-01

    The conventional oxalate method for precipitating thorium and the rare earth elements in acid solution exhibits definite solubilities of these elements. The present work was undertaken to establish conditions overcoming these solubilities and to find optimum conditions for precipitating thorium and the rare earth elements as hydroxides and sebacates. The investigations resulted in a reliable procedure applicable to samples in which the cerium group elements predominate. The oxalate precipitations are made from homogeneous solution at pH 2 by adding a prepared solution of anhydrous oxalic acid in methanol instead of the more expensive crystalline methyl oxalate. Calcium is added as a carrier. Quantitative precipitation of thorium and the rare earth elements is ascertained by further small additions of calcium to the supernatant liquid, until the added calcium precipitates as oxalate within 2 minutes. Calcium is removed by precipitating the hydroxides of thorium and rare earths at room temperature by adding ammonium hydroxide to pH > 10. Thorium is separated as the sebacate at pH 2.5, and the rare earths are precipitated with ammonium sebacate at pH 9. Maximum errors for combined weights of thorium and rare earth oxides on synthetic mixtures are ??0.6 mg. Maximum error for separated thoria is ??0.5 mg.

  16. Thorium Fuel Options for Sustained Transuranic Burning in Pressurized Water Reactors - 12381

    SciTech Connect

    Rahman, Fariz Abdul; Lee, John C.; Franceschini, Fausto; Wenner, Michael

    2012-07-01

    burn TRU in a thermal spectrum, while satisfying top-level operational and safety constraints. Various assembly designs have been proposed to assess the TRU burning potential of Th-based fuel in PWRs. In addition to typical homogeneous loading patterns, heterogeneous configurations exploiting the breeding potential of thorium to enable multiple cycles of TRU irradiation and burning have been devised. The homogeneous assembly design, with all pins featuring TRU in Th, has the benefit of a simple loading pattern and the highest rate of TRU transmutation, but it can be used only for a few cycles due to the rapid rise in the TRU content of the recycled fuel, which challenges reactivity control, safety coefficients and fuel handling. Due to its simple loading pattern, such assembly design can be used as the first step of Th implementation, achieving up to 3 times larger TRU transmutation rate than conventional U-MOX, assuming same fraction of MOX assemblies in the core. As the next step in thorium implementation, heterogeneous assemblies featuring a mixed array of Th-U and Th-U-TRU pins, where the U is in-bred from Th, have been proposed. These designs have the potential to enable burning an external supply of TRU through multiple cycles of irradiation, recovery (via reprocessing) and recycling of the residual actinides at the end of each irradiation cycle. This is achieved thanks to a larger breeding of U from Th in the heterogeneous assemblies, which reduces the TRU supply and thus mitigates the increase in the TRU core inventory for the multi-recycled fuel. While on an individual cycle basis the amount of TRU burned in the heterogeneous assembly is reduced with respect to the homogeneous design, TRU burning rates higher than single-pass U-MOX fuel can still be achieved, with the additional benefits of a multi-cycle transmutation campaign recycling all TRU isotopes. Nitride fuel, due its higher density and U breeding potential, together with its better thermal properties

  17. Radiation Damage Study in Natural Zircon Using Neutrons Irradiation

    SciTech Connect

    Lwin, Maung Tin Moe; Amin, Yusoff Mohd.; Kassim, Hasan Abu; Mohamed, Abdul Aziz; Karim, Julia Abdul

    2011-03-30

    Changes of atomic displacements in crystalline structure of natural zircon (ZrSiO{sub 4}) can be studied by using neutron irradiation on the surface of zircon and compared the data from XRD measurements before and after irradiation. The results of neutron irradiation on natural zircon using Pneumatic Transfer System (PTS) at PUSPATI TRIGA Research Reactor in the Malaysian Nuclear Agency are discussed in this work. The reactor produces maximum thermal power output of 1 MWatt and the neutron flux of up to 1x10{sup 13} ncm{sup -2}s{sup -1}. From serial decay processes of uranium and thorium radionuclides in zircon crystalline structure, the emission of alpha particles can produce damage in terms of atomic displacements in zircon. Hence, zircon has been extensively studied as a possible candidate for immobilization of fission products and actinides.

  18. Summary of the radiological assessment of the fuel cycle for a thorium-uranium carbide-fueled fast breeder reactor

    SciTech Connect

    Tennery, V.J.; Bomar, E.S.; Bond, W.D.; Meyer, H.R.; Morse, L.E.; Till, J.E.; Yalcintas, M.G.

    1980-01-01

    A large fraction of the potential fuel for nuclear power reactors employing fissionable materials exists as ores of thorium. In addition, certain characteristics of a fuel system based on breeding of the fissionable isotope {sup 233}U from thorium offer the possibility of a greater resistance to the diversion of fissionable material for the fabrication of nuclear weapons. This report consolidates into a single source the principal content of two previous reports which assess the radiological environmental impact of mining and milling of thorium ore and of the reprocessing and refabrication of spent FBR thorium-uranium carbide fuel.

  19. Solvent extraction of thorium(IV), uranium(VI), and europium(III) with lipophilic alkyl-substituted pyridinium salts. Final report for subcontract 9-XZ2-1123E-1, June 1, 1992--December 1, 1995

    SciTech Connect

    Ensor, D.D.

    1997-01-01

    In the treatment of high level nuclear wastes, aromatic pyridinium salts which are radiation-resistant are desired for the extraction of actinides and lanthanides. The solvent extraction of Th{sup +4}, UO{sub 2}{sup +2}, and Eu{sup +3} by three aromatic extractants, 3,5-didodecylpyridinium nitrate (35PY), 2,6-didodecylpyridinium nitrate (26PY), and 1-methyl-3,5-didodecyl-pyridinium iodide (1M35PY) has been studied in nitric acid media. The general order of extractability of the three extractants in toluene was 1M35PY>> 26PY > 35PY. The overall extraction efficiency of the metal ions was Th{sup +4} >UO{sub 2}{sup +2} > Eu{sup +3}. The extraction of HNO{sub 3}, which was competitive with the extraction of metal ions, was quantitatively investigated by NaOH titration and UV spectrometry. The loading capacity suggested that the extracted species in the organic phase for thorium was (R{sub 4}N{sup +}){sub 2}Th(NO{sub 3}{sup -}){sub 6}, where R{sub 4}N{sup +} denotes 1M35PY. A comparison of 1M35PY to the well-characterized extractant, Aliquat-336, an aliphatic ammonium salt was made. At the same extractant concentration, 1M35PY extracted thorium more efficiently than Aliquat-336 at high acidity. Thorium could be readily stripped with dilute nitric acid from 1M35PY. After irradiation of 0.1M 1M35PY with {sup 60}Co at 40R/min for 48 hours, no change in the extraction efficiency of thorium was observed.

  20. Automated refueling simulations of a CANDU for the exploitation of thorium fuels

    NASA Astrophysics Data System (ADS)

    Holmes, Bradford

    CANDU nuclear reactors are in a unique circumstance where they are able to utilize and exploit a number of different fuel options to provide power as a utility. Thorium, a fertile isotope found naturally, is one option that should be explored. Thorium is more abundant than uranium, which is the typical fuel in the reactor and the availability of thorium makes nuclear energy desirable to more countries. This document contains the culmination of a project that explores, tests, and analyzes the feasibility of using thorium in a CANDU reactor. The project first develops a set of twodimensional lattice and three dimensional control rod simulations using the DRAGON Version 4 nuclear physics codes. This step is repeated for many concentrations of thorium. The data generated in these steps is then used to determine a functional enrichment of thorium. This is done via a procedural elimination and optimization of certain key parameters including but not limited to average exit burnup and reactivity evolution. For the purposes of this project, an enrichment of 1 % thorium was found viable. Full core calculations were done using the DONJON 4 code. CANFUEL, a program which simulates the refueling operations of a CANDU reactor for this fuel type was developed and ran for a simulation period of one hundred days. The program and the fuel selection met all selected requirements for the entirety of the simulation period. CANFUEL requires optimization for fuel selection before it can be used extensively. The fuel selection was further scrutinized when a reactivity insertion event was simulated. The adjuster rod 11 withdrawal from the core was analyzed and compared to classical CANDU results in order to ensure no significant deviations or unwanted evolutions were encountered. For this case, the simulation results were deemed acceptable with no significant deviations from the classical CANDU case.

  1. The Thorium-Cycle: safe, abundant power for the new millennium

    NASA Astrophysics Data System (ADS)

    Don, May; George, Kim; Peter, Mcintyre; Charles, Meitzler; Robert, Rogers; Akhdior, Sattarov; Mustafa, Yavuz

    2001-10-01

    A design has been developed for using accelerator-driven thorium fission to produce electric power. A thorium-cycle reactor works by electro-breeding. A pattern of thorium fuel rods is supported in a vessel containing molten lead. A beam of high-energy (1 GeV) protons is targeted in the center of the vessel, and produces a copious flux of energetic neutrons by spallation. The neutrons transmute the thorium nuclei two steps up the periodic table to U233, which fissions rapidly to produce thermal energy. The lead serves as the spallation target, the moderator, and the heat exchange medium to transfer heat from the core to steam exchangers above the core. The thorium cycle has several important advantages over current uranium-cycle fission technology: it is intrinsically stable it cannot melt down; it eats its own waste; it cannot produce bomb-grade isotopes; and there are sufficient thorium reserves to supply the entire Earth’s energy economy for the next millennium. The concept of a thorium-cycle power reactor was first proposed by Rubbia in 1995. Key problems in the original concept were the proton injector (15 MW beam power), reliability of accelerator systems, and parasitic absorption of neutrons by fission products during the life of the core. We have addressed all three problems in a design for a flux-coupled stack of isochronous cyclotrons, delivering a pattern of 7 independent beams to the core. An interdisciplinary collaboration is being formed to develop the concept to a serious design.

  2. The extraction of thorium by calix[6]arene columns for urine analysis.

    PubMed

    Mekki, S; Bouvier-Capely, C; Jalouali, R; Rebière, F

    2011-03-01

    Thorium is a natural alpha-emitting element occurring in various ores and has numerous industrial applications. Routine monitoring of potentially exposed workers is generally achieved through radiobioassay (urine and faeces). The procedures currently used for analysing actinides such as thorium in urine require lengthy chemical separation associated with long counting times by alpha-spectrometry due to low activity levels. Thus, their main drawback is that they are time-consuming, which limits the frequency and flexibility of individual monitoring. In this context, this study developed new radiochemical procedures based on the use of tertbutylcalix[6]arenes bearing three carboxylic acid groups or three hydroxamic acid groups. These previous works demonstrated that these macrocyclic molecules immobilised on an inert solid support are excellent extractants for uranium, plutonium and americium. In this study, the authors investigated the thorium extraction by calix[6]arene columns. Experiments were performed on synthetic solutions and on real urine samples. The influence of various parameters, such as the thorium solution pH and the column flow rate on thorium extraction, was studied. The results showed that both calix[6]arenes are efficient to extract thorium. Thorium extraction is quantitative from pH = 2 for synthetic solution and from pH = 3 for real urine samples. This study has demonstrated that the column flow rate is a crucial parameter since its value must not be too high to achieve the steady-state complexation equilibrium. Finally, these results will be compared with those obtained for other actinides (U, Pu and Am) and the conditions of actinides' separation will be discussed.

  3. Accident analysis of heavy water cooled thorium breeder reactor

    SciTech Connect

    Yulianti, Yanti; Su’ud, Zaki; Takaki, Naoyuki

    2015-04-16

    Thorium has lately attracted considerable attention because it is accumulating as a by-product of large scale rare earth mining. The objective of research is to analyze transient behavior of a heavy water cooled thorium breeder that is designed by Tokai University and Tokyo Institute of Technology. That is oxide fueled, PWR type reactor with heavy water as primary coolant. An example of the optimized core has relatively small moderator to fuel volume ratio (MFR) of 0.6 and the characteristics of the core are burn-up of 67 GWd/t, breeding ratio of 1.08, burn-up reactivity loss during cycles of < 0.2% dk/k, and negative coolant reactivity coefficient. One of the nuclear reactor accidents types examined here is Unprotected Transient over Power (UTOP) due to withdrawing of the control rod that result in the positive reactivity insertion so that the reactor power will increase rapidly. Another accident type is Unprotected Loss of Flow (ULOF) that caused by failure of coolant pumps. To analyze the reactor accidents, neutron distribution calculation in the nuclear reactor is the most important factor. The best expression for the neutron distribution is the Boltzmann transport equation. However, solving this equation is very difficult so that the space-time diffusion equation is commonly used. Usually, space-time diffusion equation is solved by employing a point kinetics approach. However, this approach is less accurate for a spatially heterogeneous nuclear reactor and the nuclear reactor with quite large reactivity input. Direct method is therefore used to solve space-time diffusion equation which consider spatial factor in detail during nuclear reactor accident simulation. Set of equations that obtained from full implicit finite-difference method is solved by using iterative methods. The indication of UTOP accident is decreasing macroscopic absorption cross-section that results large external reactivity, and ULOF accident is indicated by decreasing coolant flow. The

  4. Accident analysis of heavy water cooled thorium breeder reactor

    NASA Astrophysics Data System (ADS)

    Yulianti, Yanti; Su'ud, Zaki; Takaki, Naoyuki

    2015-04-01

    Thorium has lately attracted considerable attention because it is accumulating as a by-product of large scale rare earth mining. The objective of research is to analyze transient behavior of a heavy water cooled thorium breeder that is designed by Tokai University and Tokyo Institute of Technology. That is oxide fueled, PWR type reactor with heavy water as primary coolant. An example of the optimized core has relatively small moderator to fuel volume ratio (MFR) of 0.6 and the characteristics of the core are burn-up of 67 GWd/t, breeding ratio of 1.08, burn-up reactivity loss during cycles of < 0.2% dk/k, and negative coolant reactivity coefficient. One of the nuclear reactor accidents types examined here is Unprotected Transient over Power (UTOP) due to withdrawing of the control rod that result in the positive reactivity insertion so that the reactor power will increase rapidly. Another accident type is Unprotected Loss of Flow (ULOF) that caused by failure of coolant pumps. To analyze the reactor accidents, neutron distribution calculation in the nuclear reactor is the most important factor. The best expression for the neutron distribution is the Boltzmann transport equation. However, solving this equation is very difficult so that the space-time diffusion equation is commonly used. Usually, space-time diffusion equation is solved by employing a point kinetics approach. However, this approach is less accurate for a spatially heterogeneous nuclear reactor and the nuclear reactor with quite large reactivity input. Direct method is therefore used to solve space-time diffusion equation which consider spatial factor in detail during nuclear reactor accident simulation. Set of equations that obtained from full implicit finite-difference method is solved by using iterative methods. The indication of UTOP accident is decreasing macroscopic absorption cross-section that results large external reactivity, and ULOF accident is indicated by decreasing coolant flow. The

  5. Tissue irradiator

    DOEpatents

    Hungate, F.P.; Riemath, W.F.; Bunnell, L.R.

    1975-12-16

    A tissue irradiator is provided for the in-vivo irradiation of body tissue. The irradiator comprises a radiation source material contained and completely encapsulated within vitreous carbon. An embodiment for use as an in- vivo blood irradiator comprises a cylindrical body having an axial bore therethrough. A radioisotope is contained within a first portion of vitreous carbon cylindrically surrounding the axial bore, and a containment portion of vitreous carbon surrounds the radioisotope containing portion, the two portions of vitreous carbon being integrally formed as a single unit. Connecting means are provided at each end of the cylindrical body to permit connections to blood- carrying vessels and to provide for passage of blood through the bore. In a preferred embodiment, the radioisotope is thulium-170 which is present in the irradiator in the form of thulium oxide. A method of producing the preferred blood irradiator is also provided, whereby nonradioactive thulium-169 is dispersed within a polyfurfuryl alcohol resin which is carbonized and fired to form the integral vitreous carbon body and the device is activated by neutron bombardment of the thulium-169 to produce the beta-emitting thulium-170.

  6. [Food irradiation].

    PubMed

    Migdał, W

    1995-01-01

    A worldwide standard on food irradiation was adopted in 1983 by Codex Alimentarius Commission of the Joint Food Standard Programme of the Food and Agriculture Organization (FAO) of the United Nations and the World Health Organization (WHO). As a result, 41 countries have approved the use of irradiation for treating one or more food items and the number is increasing. Generally, irradiation is used to: food loses, food spoilage, disinfestation, safety and hygiene. The number of countries which use irradiation for processing food for commercial purposes has been increasing steadily from 19 in 1987 to 33 today. In the frames of the national programme on the application of irradiation for food preservation and hygienization an experimental plant for electron beam processing has been established in Institute of Nuclear Chemistry and Technology. The plant is equipped with a small research accelerator Pilot (19MeV, 1 kW) and an industrial unit Elektronika (10MeV, 10 kW). On the basis of the research there were performed at different scientific institutions in Poland, health authorities have issued permission for irradiation for: spices, garlic, onions, mushrooms, potatoes, dry mushrooms and vegetables.

  7. Effects of solution pH and complexing reagents on uranium and thorium desorption under saturated equilibrium conditions

    SciTech Connect

    Wang, Yug-Yea; Yu, C.

    1992-08-01

    Three contaminated bulk surface soils were used for investigating the effect of solution pH and complexing reagents on uranium and thorium desorption. At a low solution pH, the major chemical species of uranium and thorium, uranyl UO{sub 2}{sup +2}, thorium dihydroxide Th(OH){sub 2}{sup +2}, and thorium hydroxide Th(OH){sup +3}, tend to form complexes with acetates in the solution phase, which increases the fractions of uranium and thorium desorbed into this phase. At a high solution pH, important uranium and thorium species such as uranyl tricarbonate complex UO{sub 2}(CO){sub 3}{sub 3}{sup {minus}4} and thorium tetrahydroxide complex Th(OH){sub 4} tend to resist complexation with acetates. The presence of complexing reagents in solution can release radionuclides such as uranium and/or thorium from the soil to the solution by forming soluble complexes. Sodium bicarbonate (NaHCO{sub 3}) and diethylenetriaminepentaacetic acid (DTPA) are strong complex formers that released 38% to 62% of total uranium activity and 78% to 86% of total thorium activity, respectively, from the soil samples investigated. Solutions of 0.1 molar sodium nitrate (NaNO{sub 3}) and 0.1 molar sodium sulfate (Na{sub 2}SO{sub 4}) were not effective complex formers with uranium and thorium under the experimental conditions. Fractions of uranium and thorium desorbed by 0.15g/200ml humic acid ranged from 4.62% to 6.17% and 1.59% to 7.09%, respectively. This work demonstrates the importance of a knowledge of solution chemistry in investigating the desorption of radionuclides.

  8. Effects of solution pH and complexing reagents on uranium and thorium desorption under saturated equilibrium conditions

    SciTech Connect

    Wang, Yug-Yea; Yu, C.

    1992-01-01

    Three contaminated bulk surface soils were used for investigating the effect of solution pH and complexing reagents on uranium and thorium desorption. At a low solution pH, the major chemical species of uranium and thorium, uranyl UO{sub 2}{sup +2}, thorium dihydroxide Th(OH){sub 2}{sup +2}, and thorium hydroxide Th(OH){sup +3}, tend to form complexes with acetates in the solution phase, which increases the fractions of uranium and thorium desorbed into this phase. At a high solution pH, important uranium and thorium species such as uranyl tricarbonate complex UO{sub 2}(CO){sub 3}{sub 3}{sup {minus}4} and thorium tetrahydroxide complex Th(OH){sub 4} tend to resist complexation with acetates. The presence of complexing reagents in solution can release radionuclides such as uranium and/or thorium from the soil to the solution by forming soluble complexes. Sodium bicarbonate (NaHCO{sub 3}) and diethylenetriaminepentaacetic acid (DTPA) are strong complex formers that released 38% to 62% of total uranium activity and 78% to 86% of total thorium activity, respectively, from the soil samples investigated. Solutions of 0.1 molar sodium nitrate (NaNO{sub 3}) and 0.1 molar sodium sulfate (Na{sub 2}SO{sub 4}) were not effective complex formers with uranium and thorium under the experimental conditions. Fractions of uranium and thorium desorbed by 0.15g/200ml humic acid ranged from 4.62% to 6.17% and 1.59% to 7.09%, respectively. This work demonstrates the importance of a knowledge of solution chemistry in investigating the desorption of radionuclides.

  9. Thorium-mediated ring-opening of tetrahydrofuran and the development of a new thorium starting material: preparation and chemistry of ThI4(DME)2.

    PubMed

    Travia, Nicholas E; Monreal, Marisa J; Scott, Brian L; Kiplinger, Jaqueline L

    2012-12-28

    The thorium(IV) tetraiodide complex ThI(4)(DME)(2) (3) (DME = 1,2-dimethoxyethane) has been prepared in high yield by reacting the corresponding chloride complex ThCl(4)(DME)(2) with an excess of trimethylsilyl iodide (Me(3)SiI) in toluene. This new route avoids the use of thorium metal as a reagent. ThI(4)(DME)(2) (3) exhibits excellent thermal stability compared to ThI(4)(THF)(4) (1), which undergoes rapid ring-opening of THF at ambient temperature to yield the iodobutoxide complex ThI(3)[O(CH(2))(4)I](THF)(3) (2). Subsequent ligand-exchange between 2 and DME affords ThI(3)[O(CH(2))(4)I](DME)(2) (11), which can be converted to 3 with Me(3)SiI. Salt metathesis between 2 and K(L(Me)) (L(Me) = (2,6-(i)Pr(2)C(6)H(3))NC(Me)CHC(Me)N(2,6-(i)Pr(2)C(6)H(3))) cleanly gives (L(Me))ThI(2)[O(CH(2))(4)I](THF) (10), which is a rare example of a thorium β-diketiminate complex. Complexes 2, 10, and 11 represent the first reported examples of THF ring-opening mediated by thorium. The synthetic utility of ThI(4)(DME)(2) (3) is demonstrated by preparation of thorium(IV) alkoxide, amide, and organometallic compounds.

  10. Defect stability in thorium monocarbide: An ab initio study

    NASA Astrophysics Data System (ADS)

    Wang, Chang-Ying; Han, Han; Shao, Kuan; Cheng, Cheng; Huai, Ping

    2015-09-01

    The elastic properties and point defects of thorium monocarbide (ThC) have been studied by means of density functional theory based on the projector-augmented-wave method. The calculated electronic and elastic properties of ThC are in good agreement with experimental data and previous theoretical results. Five types of point defects have been considered in our study, including the vacancy defect, interstitial defect, antisite defect, schottky defect, and composition-conserving defect. Among these defects, the carbon vacancy defect has the lowest formation energy of 0.29 eV. The second most stable defect (0.49 eV) is one of composition-conserving defects in which one carbon is removed to another carbon site forming a C2 dimer. In addition, we also discuss several kinds of carbon interstitial defects, and predict that the carbon trimer configuration may be a transition state for a carbon dimer diffusion in ThC. Project supported by the International S&T Cooperation Program of China (Grant No. 2014DFG60230), the National Natural Science Foundation of China (Grant No. 91326105), the National Basic Research Program of China (Grant No. 2010CB934504), and the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA02040104).

  11. Reconnaissance for uranium and thorium in Alaska, 1954

    USGS Publications Warehouse

    Matzko, John J.; Bates, Robert G.

    1957-01-01

    During 1954 reconnaissance investigations to locate minable deposits of uranium and thorium in Alaska were unsuccessful. Areas examined, from which prospectors had submitted radioactive samples, include Cap Yakataga, Kodiak Island, and Shirley Lake. Unconcentrated gravels from the beach at Cape Yakataga average about 0.001 percent equivalent uranium. Uranothorianite has been identified by X-ray diffraction data and is the principal source of radioactivity in the Cape Yakataga beach sands studied; but the zircon, monazite, and uranothorite are also radioactive. The black, opaque uranothorianite generally occurs as minute euhedral cubs, the majority of which will pass through a 100-mesh screen. The bedrock source of the radioactive samples from Kodiak Island was not found; the maximum radioactivity of samples from the Shirley Lake area was equivalent to about 0.02 percent uranium. Radiometric traverses of the 460-foot level of the Garnet shaft of the Nixon Fork mine in the Nixon Fork mining district indicated a maximum of 0.15 mr/hr. In the Hot Springs district, drill hole concentrates of gravels examined contained a maximum of 0.03 percent equivalent uranium. A radioactivity anomaly noted during the Survey's airborne reconnaissance of portions of the Territory during 1954 is located in the Fairhaven district. A ground check disclosed that the radioactivity was due to accessory minerals in the granitic rock.

  12. Ion Source Development for Ultratrace Detection of Uranium and Thorium

    SciTech Connect

    Liu, Yuan; Batchelder, Jon Charles; Galindo-Uribarri, Alfredo {nmn}; Stracener, Daniel W

    2015-01-01

    A hot-cavity surface ionization source and a hot-cavity laser ion source are evaluated in terms of ionization efficiencies for generating ion beams of U and Th. The work is motivated by the need for more efficient ion sources for detecting ultratrace U and Th impurities in a copper matrix by mass spectrometry techniques such as accelerator mass spectrometry (AMS). The performances of the ion sources are characterized using uranyl nitrate and thorium nitrate sample materials and sample sizes of 20 - 40 g of U or Th. For the surface source, the dominant ion beams observed are UO+ or ThO+ and ionization efficiencies of 2-4% have been obtained with W and Re cavities. Three-step resonant photoionization of U atoms is studied and an ionization efficiency of 8.7% has been obtained with the laser ion source. The positive ion sources promise more than an order of magnitude more efficient than conventional Cs-sputter negative ion sources used for AMS. In addition, the laser ion source is highly selective and effective in suppressing interfering and ions. Work is in progress to improve the efficiencies of both positive ion sources.

  13. Natural thorium isotopes in marine sediment core off Labuan port

    SciTech Connect

    Hafidz, B. Y.; Asnor, A. S.; Terence, R. C.; Mohamed, C. A. R.

    2014-02-12

    Sediment core was collected from Labuan port and analyzed to determine the radioactivity of thorium (Th) isotopes. The objectives of this study are to determine the possible sources of Th isotopes at Labuan port and estimates the sedimentation rate based on {sup 228}Th/{sup 232}Th model. The results suggest the {sup 230}Th and {sup 232}Th might be originated from terrestrial sedimentary rock while {sup 228}Th originated by authigenic origin. High ratio value of {sup 230}Th/{sup 232}Th detected at the top surface sediment indicates the increasing of {sup 230}Th at the recent years which might be contributed from the anthropogenic sources. The sedimentation rate of core sediment from Labuan Port was successfully estimated by using {sup 228}Th/{sup 232}Th model. The result show high sedimentation rate with 4.67 cm/year indicates rapid deposition occurred at this study area due to the high physical activity at the Labuan port. By assume the constant sedimentation rate at this area; we estimated the age of 142 cm core sediment obtained from Labuan port is 32 years started from 1981 to 2012. This chronology will be used in forthcoming research to investigate the historical profile of anthropogenic activities affecting the Labuan port.

  14. Ion source development for ultratrace detection of uranium and thorium

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Batchelder, J. C.; Galindo-Uribarri, A.; Chu, R.; Fan, S.; Romero-Romero, E.; Stracener, D. W.

    2015-10-01

    Efficient ion sources are needed for detecting ultratrace U and Th impurities in a copper matrix by mass spectrometry techniques such as accelerator mass spectrometry (AMS). Two positive ion sources, a hot-cavity surface ionization source and a resonant ionization laser ion source, are evaluated in terms of ionization efficiencies for generating ion beams of U and Th. The performances of the ion sources are characterized using uranyl nitrate and thorium nitrate sample materials with sample sizes between 20 and 40 μg of U or Th. For the surface ion source, the dominant ion beams observed are UO+ or ThO+ and ionization efficiencies of 2-4% have been obtained with W and Re cavities. With the laser ion source, three-step resonant photoionization of U atoms has been studied and only atomic U ions are observed. An ionization efficiency of about 9% has been demonstrated. The performances of both ion sources are expected to be further improved.

  15. Stability of dilute solutions of uranium, lead, and thorium ions

    USGS Publications Warehouse

    Milkey, R.G.

    1954-01-01

    Standard solutions and samples containing a few micrograms of metallic ions per milliliter are frequently used in determination of trace elements. It is important to know whether the concentrations of such solutions remain constant from day to day. The stability of dilute solutions of three metallic ions-uranium, lead, and thorium-has been investigated. Solutions containing concentrations of metallic ions, ranging from 1000 to 0.1 ?? per milliliter, were allowed to stand for approximately 2.5 months, and then the metallic ion content of those solutions that had lost strength was determined. Both adsorption and hydrolysis variously influenced the solute loss, but the minimum pH at which loss of concentration of lead and uranium occurred seemed to coincide with the pH at which the hydrolyzed metal ions began to precipitate. No increase in the stability of the solutions was obtained by substituting polyethylene containers for borosilicate glass. The solutions that lost strength could not be restored promptly to the original concentration by manual means, such as shaking them vigorously for several minutes.

  16. The Liquid Fluoride Thorium Reactor: Energy Cheaper Than Coal

    NASA Astrophysics Data System (ADS)

    Stone, Cavan

    2011-11-01

    This century, we face significant environmental challenges. Our demand for limited natural resources is rapidly increasing and much of humanity is concerned about the consequences. Our unsustainably growing population drives these challenges, and humanely stabilizing it would alleviate these pressures. Demographic data clearly shows that prosperity stabilizes population and it also shows that prosperity critically requires energy. In spite of the pressing and demonstrable nature of these challenges however, politically there is no international consensus on global energy policy. Developing nations simply will not accept a policy that will hamper their economic growth. Yet, we do have a solution to these challenges, an idea conceived and experimentally tested by Alvin Weinberg at Oak Ridge National Laboratory, the Liquid Fluoride Thorium Reactor. Presently, various laboratories and start-up companies, including the Chinese Academy of Sciences have begun efforts to commercialize the technology. By delivering the promise of inexpensive energy it will be in the economic interest of the developing nations to use this carbon-free energy source. By delivering superior performance on longstanding public concerns about nuclear energy, it will be technologically and politically feasible for developing nations to stabilize their population with the bounty of energy cheaper than coal.

  17. Triamidoamine thorium-arsenic complexes with parent arsenide, arsinidiide and arsenido structural motifs

    NASA Astrophysics Data System (ADS)

    Wildman, Elizabeth P.; Balázs, Gábor; Wooles, Ashley J.; Scheer, Manfred; Liddle, Stephen T.

    2017-03-01

    Despite a major expansion of uranium-ligand multiple bond chemistry in recent years, analogous complexes involving other actinides (An) remain scarce. For thorium, under ambient conditions only a few multiple bonds to carbon, nitrogen, phosphorus and chalcogenides are reported, and none to arsenic are known; indeed only two complexes with thorium-arsenic single bonds have been structurally authenticated, reflecting the challenges of stabilizing polar linkages at the large thorium ion. Here, we report thorium parent-arsenide (ThAsH2), -arsinidiides (ThAs(H)K and ThAs(H)Th) and arsenido (ThAsTh) linkages stabilized by a bulky triamidoamine ligand. The ThAs(H)K and ThAsTh linkages exhibit polarized-covalent thorium-arsenic multiple bonding interactions, hitherto restricted to cryogenic matrix isolation experiments, and the AnAs(H)An and AnAsAn linkages reported here have no precedent in f-block chemistry. 7s, 6d and 5f orbital contributions to the Th-As bonds are suggested by quantum chemical calculations, and their compositions unexpectedly appear to be tensioned differently compared to phosphorus congeners.

  18. Spectrophotometric study of the thorium-morin mixed-color system

    USGS Publications Warehouse

    Fletcher, M.H.; Milkey, R.G.

    1956-01-01

    A spectrophotometric study was made of the thoriummorin reaction to evaluate the suitability of morin as a reagent for the determination of trace amounts of thorium. At pH 2, the equilibrium constant for the reaction is 1 ?? 106, and a single complex having a thorium-morin ratio of 1 to 2 is formed. The complex shows maximum absorbance at a wave length of 410 m??, and its absorbance obeys Beer's law. The absorbance readings are highly reproducible, and the sensitivity is relatively high, an absorbance difference of 0.001 being equivalent to 0.007 ?? of ThO2 per sq. cm. The effects of acid, alcohol, and morin concentration, time, temperature, and age of the morin reagent as well as the behavior of morin with zirconium(IV), iron(III), aluminum(III), ytterbium(III), yttrium(III), uranium(VI), praseodymium(III), lead(II), lanthanum(III), and calcium(II) ions are discussed. A method is presented for the determination of thorium in pure solutions. Appropriate separations for the isolation of thorium may extend the usefulness of the method and permit the determination of trace amounts of thorium in complex materials.

  19. Southern complex: geology, geochemistry, mineralogy, and mineral chemistry of selected uranium- and thorium-rich granites

    SciTech Connect

    Hoffman, M.A.

    1987-01-01

    Four major rock groups are defined in the Southern Complex: the Bell Creek Granite (BCG), the Clotted Granitoids (CGR), the Albite Granite (AGR), and the Migmatite Complex. Metatexites of the Migmatite Complex are the oldest rocks and include paleosome of a metasedimentary and metavolcanic protolith represented by Banded Iron Formation, Banded Amphibolite, and Banded Gneisses, and interlayered or crosscutting leucogranites. The CGR span the range from metatexite to diatexite and represent in-situ partial melting of metapelitic layers in the protolith during intrusion of the BCG. The BCG cuts the migmatites, is locally cut by the CGR, and was derived by partial melting of a dominantly metasedimentary protolith at some depth below the presently exposed migmatites during a regional tectonothermal event. The Albite Granite is a 2km diameter, muscovite-fluorite-columbite-bearing intrusive stock that cuts all other major units. The thorium history of the BCG is a function of the history of monazite. The thorium history of the CGR is also dominated by monazite but the thorium content of this unit cannot be entirely accounted for by original restite monazite. The uranium history of the BCG and CGR was dominated by magmatic differentiation and post magmatic, metamorphic and supergene redistributions and is largely independent of the thorium history. The thorium and uranium history of the AGR was dominated by magmatic/deuteric processes unlike the BCG and CGR.

  20. Thorium distribution on the lunar surface observed by Chang'E-2 gamma-ray spectrometer

    NASA Astrophysics Data System (ADS)

    Wang, Xianmin; Zhang, Xubing; Wu, Ke

    2016-07-01

    The thorium distribution on the lunar surface is critical for understanding the lunar evolution. This work reports a global map of the thorium distribution on the lunar surface observed by Chang'E-2 gamma-ray spectrometer (GRS). Our work exhibits an interesting symmetrical structure of thorium distribution along the two sides of the belt of Th hot spots. Some potential positions of KREEP volcanism are suggested, which are the Fra Mauro region, Montes Carpatus, Aristarchus Plateau and the adjacent regions of Copernicus Crater. Based on the lunar map of thorium distribution, we draw some conclusions on two critical links of lunar evolution: (1) the thorium abundance within the lunar crust and mantle, in the last stage of Lunar Magma Ocean (LMO) crystallization, may have a positive correlation with the depth in the crust, reaches a peak when coming through the transitional zone between the crust and mantle, and decreases sharply toward the inside of the mantle; thus, the Th-enhanced materials originated from the lower crust and the layer between the crust and mantle, (2) in PKT, KREEP volcanism might be the primary mechanism of Th-elevated components to the lunar surface, whereas the Imbrium impact acted as a relatively minor role.

  1. Potential of Melastoma malabathricum as bio-accumulator for uranium and thorium from soil

    SciTech Connect

    Saat, Ahmad; Kamsani, Ain Shaqina; Kamri, Wan Nur Aina Nadzira; Talib, Nur Hasyimah Mat; Wood, Ab Khalik; Hamzah, Zaini

    2015-04-29

    Uranium and Thorium are naturally occuring radionuclides. However, due to anthropogenic activities in some locations their concentrations in the soils could be elevated. This study explores the potential of Melastoma malabathricum (locally known as ‘pokok senduduk’) as bio-accumulator of uranium and thorium from soils of three different study areas, namely former tin mining, industrial and residential/commercial areas in Peninsular Malaysia. The study found elevated concentrations of uranium and thorium in former tin mining soils as compared to natural abundance. However in industral and residential/commercial areas the concentrations are within the range of natural abundance. In terms of transfer factor (TF), in ex-mining areas TF > 1 for uranium in the leaf, stem and roots, indicating accumulation of uranium from soil. However for thorium TF < 1, indicating the occurence of transfer from soil to root, stem and leaf, but no accumulation. For other areas only transfer of uranium and thorium were observed. The results indicated the potential of Melastoma malabathricum to be used as bio-accumulatior of uranium, especially in areas of elevated concentration.

  2. Floatation-spectrophotometric Determination of Thorium, Using Complex Formation with Eriochrome Cyanine R

    PubMed Central

    Shiri, Sabah; Delpisheh, Ali; Haeri, Ali; Poornajaf, Abdolhossein; Khezeli, Tahereh; Badkiu, Nadie

    2011-01-01

    A novel and sensitive floatation-spectrophotometric method is presented for determination of trace amounts of thorium in water samples. The method is based on the ion-associated formation between thorium, Eriochrome cyanine R and Brij-35 at pH = 4 media. The complex was floated in the interface of the aqueous phase and n-hexane by vigorous shaking. After removing the aqueous phase the floated particles were dissolved in methanol and the absorbance was measured at 607 nm. The influence of different important parameters such as Eriochrome cyanine R and surfactants concentration, pH, volume of n-hexane, standing time and interfering ions were evaluated. Under optimized conditions the calibration graph was linear in the range of 6–230 ng mL−1 of thorium with a correlation coefficient of 0.9985. The limit of detections (LOD), based on signal to noise ratio (S/N) of 3 was 1.7 ng mL−1. The relative standard deviations for determination of 150 and 30 ng ml−1 of thorium were 3.26 and 4.41%, respectively (n = 10). The method showed a good linearity, recoveries, as well as some advantages such as sensitivity, simplicity, affordability and a high feasibility. The method was successfully applied to determine thorium in different water and urine samples. PMID:21340019

  3. Floatation-spectrophotometric Determination of Thorium, Using Complex Formation with Eriochrome Cyanine R.

    PubMed

    Shiri, Sabah; Delpisheh, Ali; Haeri, Ali; Poornajaf, Abdolhossein; Khezeli, Tahereh; Badkiu, Nadie

    2011-01-23

    A novel and sensitive floatation-spectrophotometric method is presented for determination of trace amounts of thorium in water samples. The method is based on the ion-associated formation between thorium, Eriochrome cyanine R and Brij-35 at pH = 4 media. The complex was floated in the interface of the aqueous phase and n-hexane by vigorous shaking. After removing the aqueous phase the floated particles were dissolved in methanol and the absorbance was measured at 607 nm. The influence of different important parameters such as Eriochrome cyanine R and surfactants concentration, pH, volume of n-hexane, standing time and interfering ions were evaluated. Under optimized conditions the calibration graph was linear in the range of 6-230 ng mL(-1) of thorium with a correlation coefficient of 0.9985. The limit of detections (LOD), based on signal to noise ratio (S/N) of 3 was 1.7 ng mL(-1). The relative standard deviations for determination of 150 and 30 ng ml(-1) of thorium were 3.26 and 4.41%, respectively (n = 10). The method showed a good linearity, recoveries, as well as some advantages such as sensitivity, simplicity, affordability and a high feasibility. The method was successfully applied to determine thorium in different water and urine samples.

  4. Potential of Melastoma malabathricum as bio-accumulator for uranium and thorium from soil

    NASA Astrophysics Data System (ADS)

    Saat, Ahmad; Kamsani, Ain Shaqina; Kamri, Wan Nur Aina Nadzira; Talib, Nur Hasyimah Mat; Wood, Ab Khalik; Hamzah, Zaini

    2015-04-01

    Uranium and Thorium are naturally occuring radionuclides. However, due to anthropogenic activities in some locations their concentrations in the soils could be elevated. This study explores the potential of Melastoma malabathricum (locally known as `pokok senduduk') as bio-accumulator of uranium and thorium from soils of three different study areas, namely former tin mining, industrial and residential/commercial areas in Peninsular Malaysia. The study found elevated concentrations of uranium and thorium in former tin mining soils as compared to natural abundance. However in industral and residential/commercial areas the concentrations are within the range of natural abundance. In terms of transfer factor (TF), in ex-mining areas TF > 1 for uranium in the leaf, stem and roots, indicating accumulation of uranium from soil. However for thorium TF < 1, indicating the occurence of transfer from soil to root, stem and leaf, but no accumulation. For other areas only transfer of uranium and thorium were observed. The results indicated the potential of Melastoma malabathricum to be used as bio-accumulatior of uranium, especially in areas of elevated concentration.

  5. Biomonitoring of environmental pollution by thorium and uranium in selected regions of the Republic of Kazakhstan.

    PubMed

    Zoriy, P; Ostapczuk, P; Dederichs, H; Höbig, J; Lennartz, R; Zoriy, M

    2010-05-01

    Two former uranium mines and a uranium reprocessing factory in the city of Aktau, Kazakhstan, may represent a risk of contaminating the surrounding areas by uranium and its daughter elements. One of the possible fingerprinting tools for studying the environmental contamination is using plant samples, collected in the surroundings of this city in 2007 and 2008. The distribution pattern of environmental pollution by uranium and thorium was evaluated by determining the thorium and uranium concentrations in plant samples (Artemisia austriaca) from the city of Aktau and comparing these results with those obtained for the same species of plants from an unpolluted area (town of Kurchatov). The determination of the uranium and thorium concentrations in different parts of A. austriaca plants collected from the analyzed areas demonstrated that the main contamination of the flora in areas surrounding the city of Aktau was due to dust transported by the wind from the uranium mines. The results obtained demonstrate that all the areas surrounding Aktau have a higher pollution level due to thorium and uranium than the control area (Kurchatov). A few "hot points" with high concentrations of uranium and thorium were found near the uranium reprocessing factory and the uranium mines.

  6. 78 FR 21352 - Update on Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-10

    ... will be provided from the Uranium Enrichment Decontamination and Decommissioning Fund established at... on Reimbursement for Costs of Remedial Action at Active Uranium and Thorium Processing Sites AGENCY... reimbursement for cleanup work performed by licensees at eligible uranium and thorium processing sites in...

  7. Irradiation subassembly

    DOEpatents

    Seim, O.S.; Filewicz, E.C.; Hutter, E.

    1973-10-23

    An irradiation subassembly for use in a nuclear reactor is described which includes a bundle of slender elongated irradiation -capsules or fuel elements enclosed by a coolant tube and having yieldable retaining liner between the irradiation capsules and the coolant tube. For a hexagonal bundle surrounded by a hexagonal tube the yieldable retaining liner may consist either of six segments corresponding to the six sides of the tube or three angular segments each corresponding in two adjacent sides of the tube. The sides of adjacent segments abut and are so cut that metal-tometal contact is retained when the volume enclosed by the retaining liner is varied and Springs are provided for urging the segments toward the center of the tube to hold the capsules in a closely packed configuration. (Official Gazette)

  8. Delineating the major KREEP-bearing terranes on the moon with global measurements of absolute thorium abundances

    SciTech Connect

    Lawrence, D.J.; Feldman, W.C.; Barraclough, B.L.; Elphic, R.C.; Prettyman, T.H.; Binder, A.B.; Maurice, S.; Miller, M.C.

    1999-03-01

    The Lunar Prospector (LP) Gamma-Ray Spectrometer (GRS) has been used to map the global composition of thorium on the lunar surface. Previous LP results of relative thorium abundances demonstrated that thorium is highly concentrated in and around the nearside western maria and less so in the South Pole Aitken (SPA) basin. Using new detector modeling results and a larger data set, the authors present here a global map of absolute thorium abundances on a 2{degree} by 2{degree} equal-area pixel scale. Because thorium is a tracer of KREEP-rich material, these data provide fundamental information regarding the locations and importance of terranes that are rich in KREEP bearing materials.

  9. Development of pyro-processing technology for thorium-fuelled molten salt reactor

    SciTech Connect

    Uhlir, J.; Straka, M.; Szatmary, L.

    2012-07-01

    The Molten Salt Reactor (MSR) is classified as the non-classical nuclear reactor type based on the specific features coming out from the use of liquid fuel circulating in the MSR primary circuit. Other uniqueness of the reactor type is based on the fact that the primary circuit of the reactor is directly connected with the on-line reprocessing technology, necessary for keeping the reactor in operation for a long run. MSR is the only reactor system, which can be effectively operated within the {sup 232}Th- {sup 233}U fuel cycle as thorium breeder with the breeding factor significantly higher than one. The fuel cycle technologies proposed as ford the fresh thorium fuel processing as for the primary circuit fuel reprocessing are pyrochemical and mainly fluoride. Although these pyrochemical processes were never previously fully verified, the present-day development anticipates an assumption for the successful future deployment of the thorium-fuelled MSR technology. (authors)

  10. Conceptual design study of small long-life PWR based on thorium cycle fuel

    SciTech Connect

    Subkhi, M. Nurul; Su'ud, Zaki; Waris, Abdul; Permana, Sidik

    2014-09-30

    A neutronic performance of small long-life Pressurized Water Reactor (PWR) using thorium cycle based fuel has been investigated. Thorium cycle which has higher conversion ratio in thermal region compared to uranium cycle produce some significant of {sup 233}U during burn up time. The cell-burn up calculations were performed by PIJ SRAC code using nuclear data library based on JENDL 3.3, while the multi-energy-group diffusion calculations were optimized in whole core cylindrical two-dimension R-Z geometry by SRAC-CITATION. this study would be introduced thorium nitride fuel system which ZIRLO is the cladding material. The optimization of 350 MWt small long life PWR result small excess reactivity and reduced power peaking during its operation.

  11. Conceptual design study of small long-life PWR based on thorium cycle fuel

    NASA Astrophysics Data System (ADS)

    Subkhi, M. Nurul; Su'ud, Zaki; Waris, Abdul; Permana, Sidik

    2014-09-01

    A neutronic performance of small long-life Pressurized Water Reactor (PWR) using thorium cycle based fuel has been investigated. Thorium cycle which has higer conversion ratio in thermal region compared to uranium cycle produce some significant of 233U during burn up time. The cell-burn up calculations were performed by PIJ SRAC code using nuclear data library based on JENDL 3.3, while the multi-energy-group diffusion calculations were optimized in whole core cylindrical two-dimension R-Z geometry by SRAC-CITATION. this study would be introduced thorium nitride fuel system which ZIRLO is the cladding material. The optimization of 350 MWt small long life PWR result small excess reactivity and reduced power peaking during its operation.

  12. Integral experiments on thorium assemblies with D-T neutron source

    NASA Astrophysics Data System (ADS)

    Liu, Rong; Yang, Yiwei; Feng, Song; Zheng, Lei; Lai, Caifeng; Lu, Xinxin; Wang, Mei; Jiang, Li

    2017-09-01

    To validate nuclear data and code in the neutronics design of a hybrid reactor with thorium, integral experiments in two kinds of benchmark thorium assemblies with a D-T fusion neutron source have been performed. The one kind of 1D assemblies consists of polyethylene and depleted uranium shells. The other kind of 2D assemblies consists of three thorium oxide cylinders. The capture reaction rates, fission reaction rates, and (n, 2n) reaction rates in 232Th in the assemblies are measured by ThO2 foils. The leakage neutron spectra from the ThO2 cylinders are measured by a liquid scintillation detector. The experimental uncertainties in all the results are analyzed. The measured results are compared to the calculated ones with MCNP code and ENDF/B-VII.0 library data.

  13. Study of the behaviour of thorium adsorption on PAN/zeolite composite adsorbent.

    PubMed

    Kaygun, A Kilincarslan; Akyil, S

    2007-08-17

    The adsorption behaviour of thorium from aqueous solutions by a composite adsorbent has been investigated by a batch technique. The thorium adsorption on composite adsorbent was studied as a function of initial concentration, pH, shaking time and temperature. The sorption of thorium at the determined optimum conditions follows Langmuir, Freundlich and D-R type isotherms. Langmuir constants Q=0.04 mmol g(-1) and b=64.94 L mol(-1) and of D-R parameter Xm = 0.04, beta=0.79 and of sorption energy E=0.80 and Freundlich constants 1/n=3.12 and cm = 0.012 mmol g(-1) were evaluated. Thermodynamic parameters such as DeltaH and DeltaS were found to be 37.32 kJ mol(-1) and 206.17 J mol(-1)K(-1), respectively.

  14. Application of hollow cylindrical wheat stem for electromembrane extraction of thorium in water samples

    NASA Astrophysics Data System (ADS)

    Khajeh, Mostafa; Pedersen-Bjergaard, Stig; Barkhordar, Afsaneh; Bohlooli, Mousa

    2015-02-01

    In this study, wheat stem was used for electromembrane extraction (EME) for the first time. The EME technique involved the use of a wheat stem whose channel was filled with 3 M HCl, immersed in 10 mL of an aqueous sample solution. Thorium migrated from aqueous samples, through a thin layer of 1-octanol and 5%v/v Di-(2-ethylhexyl) phosphate (DEHP) immobilized in the pores of a porous stem, and into an acceptor phase solution present inside the lumen of the stem. The pH of donor and acceptor phases, extraction time, voltage, and stirring speed were optimized. At the optimum conditions, an enrichment factor of 50 and a limit of detection of 0.29 ng mL-1 was obtained for thorium. The developed procedure was then applied to the extraction and determination of thorium in water samples and in reference material.

  15. Application of hollow cylindrical wheat stem for electromembrane extraction of thorium in water samples.

    PubMed

    Khajeh, Mostafa; Pedersen-Bjergaard, Stig; Barkhordar, Afsaneh; Bohlooli, Mousa

    2015-02-25

    In this study, wheat stem was used for electromembrane extraction (EME) for the first time. The EME technique involved the use of a wheat stem whose channel was filled with 3 M HCl, immersed in 10 mL of an aqueous sample solution. Thorium migrated from aqueous samples, through a thin layer of 1-octanol and 5%v/v Di-(2-ethylhexyl) phosphate (DEHP) immobilized in the pores of a porous stem, and into an acceptor phase solution present inside the lumen of the stem. The pH of donor and acceptor phases, extraction time, voltage, and stirring speed were optimized. At the optimum conditions, an enrichment factor of 50 and a limit of detection of 0.29 ng mL(-1) was obtained for thorium. The developed procedure was then applied to the extraction and determination of thorium in water samples and in reference material.

  16. New Evidence Suggests Thorium Enrichment in Lunar Mare Basalts of the Western Procellarum Region

    NASA Astrophysics Data System (ADS)

    Jolliff, B. L.; Gillis, J. J.; Lawrence, D. J.; Maurice, S.

    2001-05-01

    Recent orbital remote-sensing missions have provided new compositional information about the global distribution of basalt types on the Moon. Previous work suggested a wide distribution of basalts of intermediate Ti content, which are rare in the lunar sample collections, and the occurrence of other basalts that are compositionally or mineralogically dissimilar to the returned samples and lunar basaltic meteorites. Measurement of thorium concentrations by Lunar Prospector's gamma-ray spectrometer reveal some basalt flows in the Procellarum region to have elevated thorium concentrations relative to most of the sampled basalts. Clementine UVVIS derived FeO estimates suggest that these basalts, with ~20 wt% FeO, do not derive their thorium enrichment from contamination by KREEP-rich Imbrium ejecta, re-excavated from beneath basalts by young craters such as Kepler and Aristarchus. Enrichment in thorium may result from assimilation of crustal rocks prior to eruption or from KREEP enrichment in mantle source regions. Distinguishing between these possibilities is needed to determine whether any cause-effect relationships exist between the enrichment of heat-producing Th, U, and K in the Procellarum KREEP Terrane and features such as the lack of anorthositic crust in the region, relaxation of topography across the Procellarum basin, and extended volcanism that occurred there. To investigate these basalts, we integrate Lunar Prospector gamma-ray data (resampled to 0.5 degree resolution), Clementine spectral reflectance (using modified algorithms to derive FeO and TiO2 concentrations), Lunar Orbiter images, and photogeologic maps. Results to date suggest significant enrichment of thorium in Eratosthenian basalts of Western Procellarum at levels of ~3-5 ppm, similar to concentrations measured in some Apollo 11 high-K basalts from Mare Tranquillitatis and in rare incompatible-element-rich basaltic glasses from Apollo 14 and Apollo 15 samples. It is unclear at present whether

  17. Determination of thorium isotopes in mineral and environmental water and soil samples by alpha-spectrometry and the fate of thorium in water.

    PubMed

    Jia, Guogang; Torri, G; Ocone, R; Di Lullo, A; De Angelis, A; Boschetto, R

    2008-10-01

    A method has been developed for determination of thorium isotopes in water and soil samples by alpha-spectrometry. After fusion with Na(2)CO(3) and Na(2)O(2) at 600 degrees C, soil samples were leached with HNO(3) and HCl. Thorium in water sample or in soil leaching solution was coprecipitated together with iron (III) as hydroxides and/or carbonates at pH 9 with ammonia solution, separated from uranium and other alpha-emitters by a Microthene-TOPO (tri-octyl-phosphine oxide) chromatographic column, electrodeposited on a stainless steel disk, and measured by alpha-spectrometry. The method was checked with two certified reference materials supplied by the IAEA, and reliable results were obtained. The detection limits of the method for water (soil) samples are 0.44 microBq l(-1) (0.070 Bq kg(-1)) for (232)Th, 0.80 microBq l(-1) (0.13 Bq kg(-1)) for (230)Th and 1.0 microBq l(-1) (0.16 Bq kg(-1)) for (228)Th, respectively, if 100 l of water (0.50 g) for each sample are analysed. A variety of water or soil samples were analysed using this procedure and giving average thorium yields of 75.5+/-14.2% for water and 93.4+/-4.5% for soil. The obtained concentrations of thorium isotopes in water samples are in the range of 0.0007-0.0326 mBq l(-1) for (232)Th, thorium isotopes in water was studied. The exposure impact due to intake of thorium in the analysed drinking water was evaluated, showing a negligible amount of dose contribution. The concentrations of (232)Th, (230)Th and (228)Th in the analysed soil samples are in the range of 30.2-48.6, 32.5-60.5 and 31.0-53.0 Bq kg(-1), respectively. The obtained mean ratio is 1.04+/-0.05 for (228)Th/(232)Th and 1.20+/-0.41 for (230)Th/(232)Th.

  18. Updated determination of particulate and dissolved thorium-234

    NASA Astrophysics Data System (ADS)

    Fleer, Alan P.

    The determination of particulate and dissolved 234Th is similar to the procedure of Anderson and Fleer [1982]. Samples are collected using 30 L Niskin bottles with Teflon- or epoxy-coated internal springs. On deck, the sample is pumped with a delrin impeller pump through a 0.45 μm pore size 147-mm diameter Millipore filter and into a pre-rinsed 6 gallon plastic cubitainer held in a plastic milk crate. An in-line plastic water meter records volumes in gallons. The particulate sample filter is folded twice and stored in a polyethylene sample bag. To the ˜20 L filtered sample is added: 30 mL reagent grade 16 N HNO3; 500 mL 230Th tracer of ˜30 dpm mL-l and 5 mL 50 mg mL-l iron carrier previously cleaned by extraction into isopropyl ether from an 8 M HCl solution and back-extracted into 0.1 M HCl. The acidified sample is allowed to equilibrate for from one day to a maximum of several days. The sample is weighed on a Heathkit digital scale and the pH is adjusted to approximately 8 with about 40 mL 10 M NH4OH to precipitate iron hydroxide, which carries the thorium and uranium from the solution. The precipitate is allowed to settle for 12 to 24 hours. The supernate is drawn off, and the precipitate is spun down in a centrifuge tube to about an 8 mL volume. The precipitate is resuspended in distilled water and spun down again, then dissolved in three times its volume with 12 N HCl to make a 9 N HCl solution. A 1.5 cm×12 cm ion exchange column is filled with AG1×8 100-200 mesh resin and conditioned with 9 N HCl. The sample solution is run slowly through.

  19. A method for the rapid radiochemical analysis of uranium and thorium isotopes in impure carbonates.

    PubMed

    Elyahyaoui, A; Zarki, R; Chiadli, A

    2003-01-01

    A simple method combining solvent extraction and electrodeposition procedures is described for the determination of the isotopic composition and content of uranium and thorium in travertine samples. The actinide elements are extracted with diethyl ether from a calcium nitrate solution. The isolation of the elements and the alpha source preparation are performed in two steps after the sample digestion. The acid leaching of samples is performed using both partial and total dissolution methods. High recoveries of both uranium and thorium and good alpha-spectra are obtained with both partial and total dissolution methods. Copyright 2002 Elsevier Science Ltd.

  20. Protactinium-231 and thorium-230 abundances and high scavenging rates in the western arctic ocean

    PubMed

    Edmonds; Moran; Hoff; Smith; Edwards

    1998-04-17

    The Canadian Basin of the Arctic Ocean, largely ice covered and isolated from deep contact with the more dynamic Eurasian Basin by the Lomonosov Ridge, has historically been considered an area of low productivity and particle flux and sluggish circulation. High-sensitivity mass-spectrometric measurements of the naturally occurring radionuclides protactinium-231 and thorium-230 in the deep Canada Basin and on the adjacent shelf indicate high particle fluxes and scavenging rates in this region. The thorium-232 data suggest that offshore advection of particulate material from the shelves contributes to scavenging of reactive materials in areas of permanent ice cover.

  1. Global Uranium And Thorium Resources: Are They Adequate To Satisfy Demand Over The Next Half Century?

    NASA Astrophysics Data System (ADS)

    Lambert, I. B.

    2012-04-01

    This presentation will consider the adequacy of global uranium and thorium resources to meet realistic nuclear power demand scenarios over the next half century. It is presented on behalf of, and based on evaluations by, the Uranium Group - a joint initiative of the OECD Nuclear Energy Agency and the International Atomic Energy Agency, of which the author is a Vice Chair. The Uranium Group produces a biennial report on Uranium Resources, Production and Demand based on information from some 40 countries involved in the nuclear fuel cycle, which also briefly reviews thorium resources. Uranium: In 2008, world production of uranium amounted to almost 44,000 tonnes (tU). This supplied approximately three-quarters of world reactor requirements (approx. 59,000 tU), the remainder being met by previously mined uranium (so-called secondary sources). Information on availability of secondary sources - which include uranium from excess inventories, dismantling nuclear warheads, tails and spent fuel reprocessing - is incomplete, but such sources are expected to decrease in market importance after 2013. In 2008, the total world Reasonably Assured plus Inferred Resources of uranium (recoverable at less than 130/kgU) amounted to 5.4 million tonnes. In addition, it is clear that there are vast amounts of uranium recoverable at higher costs in known deposits, plus many as yet undiscovered deposits. The Uranium Group has concluded that the uranium resource base is more than adequate to meet projected high-case requirements for nuclear power for at least half a century. This conclusion does not assume increasing replacement of uranium by fuels from reprocessing current reactor wastes, or by thorium, nor greater reactor efficiencies, which are likely to ameliorate future uranium demand. However, progressively increasing quantities of uranium will need to be mined, against a backdrop of the relatively small number of producing facilities around the world, geopolitical uncertainties and

  2. Irradiated foods

    MedlinePlus

    ... it reduces the risk for food poisoning . Food irradiation is used in many countries. It was first approved in the U.S. to prevent sprouts on white potatoes, and to control insects on wheat and in certain spices and seasonings.

  3. The U.S.G.S. phosphate-fluoride-iodate method for the determination of very small amounts of thorium in naturally occurring materials

    USGS Publications Warehouse

    Crimaldi, F.S.; Fairchild, J.G.

    1949-01-01

    Detailed procedures are presented for the determination of very small percentages of thorium. The methods are designed to determine 0.001% of thorium oxide as the lower limit and are applicable to nearly all types of rocks. For quantities below a milligram of ThO2, the thorium is determined nephelometrically as the iodate or photemetrically with p-dimethylamineasephenylarsonic acid. For quantities of thorium above one milligram of ThO2, the thorium is determined gravimetrically. A discussion of the important feature of the methods and a summary of the more important experimental work that lead to the adoption of the procedures.

  4. Thorium Energy Resources and its Potential of Georgian Republic, The Caucasus

    NASA Astrophysics Data System (ADS)

    Gogoladze, Salome; Okrostsvaridze, Avtandil

    2017-04-01

    Energy resources, currently consumed by modern civilization, are represented by hydrocarbons - 78-80 %, however these reserves are exhausting. In light of these challenges, search of new energy resources is vital importance problem for the modern civilization. Based on the analysis of existing energy reserves and potential, as the main energy resources for the future of our civilization, the renewable and nuclear energy should be considered. However, thorium has a number of advantages compared to Uranium (Kazimi, 2003; et al.): It is concentrated in the earth crust 4-5 times more than uranium; extraction and enrichment of thorium is much cheaper than uranium's; It is less radioactive; complete destruction of its waste products is possible; thorium yields much more energy than uranium. Because of unique properties and currently existed difficult energetic situation thorium is considered as the main green energy resource in the 3rd millennium of the human civilization (Martin, 2009). Georgia republic, which is situated in the central part of Caucasus, poor of hydrocarbons, but has a thorium resource important potential. In general the Caucasus represents a collisional orogen, that formed along the Eurasian North continental margin and extends over 1200 km from Caspian to Black Sea. Three major units are distinguished in its construction: the Greater and Lesser Caucasian mobile belts and the Transcaucasus microplate. Currently it represents the Tethyan segment connecting the Mediterranean and Iran-Himalayan orogenic belts, between the Gondvana-derived Arabian plate and East European platform. Now in Georgian Republic are marked thorium four ore occurrences (Okrostsvaridze, 2014): 1- in the Sothern slope of the Greater Caucasus, in the quartz -plagioclases veins (Th concentrations vary between 51g/t - 3882 g/t); 2- in the Transcaucasus Dzirula massif hydrothermally altered rocks of the Precambrian quartz-diorite gneisses (Th concentrations vary between 117 g/t -266 g

  5. Is the bipyridyl thorium metallocene a low-valent thorium complex? A combined experimental and computational study

    SciTech Connect

    Ren, Wenshan; Lukens, Wayne W.; Zi, Guofu; Maron, Laurent; Walter, Marc D.

    2012-01-12

    Bipyridyl thorium metallocenes [5-1,2,4-(Me3C)3C5H2]2Th(bipy) (1) and [5-1,3-(Me3C)2C5H3]2Th(bipy) (2) have been investigated by magnetic susceptibility and computational studies. The magnetic susceptibility data reveal that 1 and 2 are not diamagnetic, but they behave as temperature independent paramagnets (TIPs). To rationalize this observation, density functional theory (DFT) and complete active space SCF (CASSCF) calculations have been undertaken, which indicated that Cp2Th(bipy) has indeed a Th(IV)(bipy2-) ground state (f0d0 2, S = 0), but the open-shell singlet (f0d1 1, S = 0) (almost degenerate with its triplet congener) is lying only 9.2 kcal/mol higher in energy. Complexes 1 and 2 react cleanly with Ph2CS to give [ 5-1,2,4-(Me3C)3C5H2]2Th[(bipy)(SCPh2)] (3) and [ 5-1,3-(Me3C)2C5H3]2Th[(bipy)(SCPh2)] (4), respectively, in quantitative conversions. Since no intermediates were observed experimentally, this reaction was also studied computationally. Coordination of Ph2CS to 2 in its S = 0 ground state is not possible, but Ph2CS can coordinate to 2 in its triplet state (S = 1) upon which a single electron transfer (SET) from the (bipy2-) fragment to Ph2CS followed by C-C coupling takes place.

  6. Cri du Chat syndrome

    PubMed Central

    Cerruti Mainardi, Paola

    2006-01-01

    The Cri du Chat syndrome (CdCS) is a genetic disease resulting from a deletion of variable size occurring on the short arm of chromosome 5 (5p-). The incidence ranges from 1:15,000 to 1:50,000 live-born infants. The main clinical features are a high-pitched monochromatic cry, microcephaly, broad nasal bridge, epicanthal folds, micrognathia, abnormal dermatoglyphics, and severe psychomotor and mental retardation. Malformations, although not very frequent, may be present: cardiac, neurological and renal abnormalities, preauricular tags, syndactyly, hypospadias, and cryptorchidism. Molecular cytogenetic analysis has allowed a cytogenetic and phenotypic map of 5p to be defined, even if results from the studies reported up to now are not completely in agreement. Genotype-phenotype correlation studies showed a clinical and cytogenetic variability. The identification of phenotypic subsets associated with a specific size and type of deletion is of diagnostic and prognostic relevance. Specific growth and psychomotor development charts have been established. Two genes, Semaphorin F (SEMAF) and δ-catenin (CTNND2), which have been mapped to the "critical regions", are potentially involved in cerebral development and their deletion may be associated with mental retardation in CdCS patients. Deletion of the telomerase reverse transcriptase (hTERT) gene, localised to 5p15.33, could contribute to the phenotypic changes in CdCS. The critical regions were recently refined by using array comparative genomic hybridisation. The cat-like cry critical region was further narrowed using quantitative polymerase chain reaction (PCR) and three candidate genes were characterised in this region. The diagnosis is based on typical clinical manifestations. Karyotype analysis and, in doubtful cases, FISH analysis will confirm the diagnosis. There is no specific therapy for CdCS but early rehabilitative and educational interventions improve the prognosis and considerable progress has been made in

  7. Cri du Chat syndrome.

    PubMed

    Cerruti Mainardi, Paola

    2006-09-05

    The Cri du Chat syndrome (CdCS) is a genetic disease resulting from a deletion of variable size occurring on the short arm of chromosome 5 (5p-). The incidence ranges from 1:15,000 to 1:50,000 live-born infants. The main clinical features are a high-pitched monochromatic cry, microcephaly, broad nasal bridge, epicanthal folds, micrognathia, abnormal dermatoglyphics, and severe psychomotor and mental retardation. Malformations, although not very frequent, may be present: cardiac, neurological and renal abnormalities, preauricular tags, syndactyly, hypospadias, and cryptorchidism. Molecular cytogenetic analysis has allowed a cytogenetic and phenotypic map of 5p to be defined, even if results from the studies reported up to now are not completely in agreement. Genotype-phenotype correlation studies showed a clinical and cytogenetic variability. The identification of phenotypic subsets associated with a specific size and type of deletion is of diagnostic and prognostic relevance. Specific growth and psychomotor development charts have been established. Two genes, Semaphorin F (SEMAF) and delta-catenin (CTNND2), which have been mapped to the "critical regions", are potentially involved in cerebral development and their deletion may be associated with mental retardation in CdCS patients. Deletion of the telomerase reverse transcriptase (hTERT) gene, localised to 5p15.33, could contribute to the phenotypic changes in CdCS. The critical regions were recently refined by using array comparative genomic hybridisation. The cat-like cry critical region was further narrowed using quantitative polymerase chain reaction (PCR) and three candidate genes were characterised in this region. The diagnosis is based on typical clinical manifestations. Karyotype analysis and, in doubtful cases, FISH analysis will confirm the diagnosis. There is no specific therapy for CdCS but early rehabilitative and educational interventions improve the prognosis and considerable progress has been made

  8. Applications attract DuPont

    SciTech Connect

    Rotman, D.

    1996-08-07

    Scientists at DuPont say they have demonstrated the first chemical processing application for high-temperature superconducting (HTS) magnets. DuPont says the work, which uses a HTS magnet to separate mineral contaminants from kaolin, points to the feasibility of a range of HTS applications in industrial processing, including those involving polymerization. DuPont`s success comes after 10 years of work to commercialize high-temperature superconductors. And while superconductors have lost much of their luster since the late 1980s, the company says it is still bullish on their prospects. {open_quotes}At the moment, there`s no real market for superconductors,{close_quotes} says Alan Lauder, general manager/superconductivity. But, he says, several potentially lucrative applications could be commercialized within the next several years.

  9. L'Aventure du LHC

    SciTech Connect

    2010-06-11

    Cette présentation s’adressera principalement aux personnes qui ont construit le LHC. La construction du LHC fut longue et difficile. De nombreux problèmes sont apparus en cours de route. Tous ont été résolus grâce au dévouement et à l’engagement du personnel et des collaborateurs. Je reviendrai sur les coups durs et les réussites qui ont marqués ces 15 dernières années et je vous montrerai combien cette machine, le fruit de vos efforts, est extraordinaire.

  10. DuPont hikes butanediol

    SciTech Connect

    Morris, G.D.L.

    1997-05-14

    Butanediol (BDO) and its derivatives continue to be strong, a positive sign for the many companies planning expansions. DuPont - one of only two global producers not planning capacity additions - has announced that it will discontinue all off-schedule pricing for BDO and two important derivatives, tetrahydrofuran (THF) and polytetramethylene ether glycol (PTMEG). DuPont`s list prices are $1.00/lb fob for BDO, about $1.40/lb for THF, and $2.00/lb for PTMEG. The price adjustment is effective this month or as contracts allow.

  11. Improvement of the thermal margins in the Swedish Ringhals-3 PWR by introducing new fuel assemblies with thorium

    SciTech Connect

    Lau, C. W.; Demaziere, C.; Nylen, H.; Sandberg, U.

    2012-07-01

    Thorium is a fertile material and most of the past research has focused on breeding thorium to fissile material. In this paper, the focus is on using thorium to improve the thermal margins by homogeneously distributing thorium in the fuel pellets. A proposed uranium-thorium-based fuel assembly is simulated for the Swedish Ringhals-3 PWR core in a realistic demonstration. All the key safety parameters, such as isothermal temperature coefficient of reactivity, Doppler temperature of reactivity, boron worth, shutdown margins and fraction of delayed neutrons are studied in this paper, and are within safety limits for the new core design using the uranium-thorium-based fuel assemblies. The calculations were performed by the two-dimensional transport code CASMO-4E and the two group steady-state three dimensional nodal code SIMULATE-3 from Studsvik Scandpower. The results showed that the uranium-thorium-based fuel assembly improves the thermal margins, both in the pin peak power and the local power (Fq). The improved thermal margins would allow more flexible core designs with less neutron leakage or could be used in power uprates to offer efficient safety margins. (authors)

  12. Smart thorium and uranium determination exploiting renewable solid-phase extraction applied to environmental samples in a wide concentration range.

    PubMed

    Avivar, Jessica; Ferrer, Laura; Casas, Montserrat; Cerdà, Víctor

    2011-07-01

    A smart fully automated system is proposed for determination of thorium and uranium in a wide concentration range, reaching environmental levels. The hyphenation of lab-on-valve (LOV) and multisyringe flow injection analysis (MSFIA), coupled to a long path length liquid waveguide capillary cell, allows the spectrophotometric determination of thorium and uranium in different types of environmental sample matrices achieving high selectivity and sensitivity levels. Online separation and preconcentration of thorium and uranium is carried out by means of Uranium and TEtraValents Actinides resin. The potential of the LOV-MSFIA makes possible the full automation of the system by the in-line regeneration of the column and its combination with a smart methodology is a step forward in automation. After elution, thorium(IV) and uranium(VI) are spectrophotometrically detected after reaction with arsenazo-III. We propose a rapid, inexpensive, and fully automated method to determine thorium(IV) and uranium(VI) in a wide concentration range (0-1,200 and 0-2,000 μg L(-1) Th and U, respectively). Limits of detection reached are 5.9 ηg L(-1) of uranium and 60 ηg L(-1) of thorium. Different water sample matrices (seawater, well water, freshwater, tap water, and mineral water), and a channel sediment reference material which contained thorium and uranium were satisfactorily analyzed with the proposed method.

  13. On the equilibrium isotopic composition of the thorium-uranium-plutonium fuel cycle

    NASA Astrophysics Data System (ADS)

    Marshalkin, V. Ye.; Povyshev, V. M.

    2016-12-01

    The equilibrium isotopic compositions and the times to equilibrium in the process of thorium-uranium-plutonium oxide fuel recycling in VVER-type reactors using heavy water mixed with light water are estimated. It is demonstrated thEhfat such reactors have a capacity to operate with self-reproduction of active isotopes in the equilibrium mode.

  14. 49 CFR 173.426 - Excepted packages for articles containing natural uranium or thorium.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false Excepted packages for articles containing natural....426 Excepted packages for articles containing natural uranium or thorium. A manufactured article in which the sole Class 7 (radioactive) material content is natural uranium, unirradiated depleted uranium...

  15. 49 CFR 173.426 - Excepted packages for articles containing natural uranium or thorium.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Excepted packages for articles containing natural....426 Excepted packages for articles containing natural uranium or thorium. A manufactured article in which the sole Class 7 (radioactive) material content is natural uranium, unirradiated depleted uranium...

  16. Energy dispersive X-Ray fluorescence determination of thorium in phosphoric acid solutions

    NASA Astrophysics Data System (ADS)

    Mirashi, N. N.; Dhara, Sangita; Kumar, S. Sanjay; Chaudhury, Satyajeet; Misra, N. L.; Aggarwal, S. K.

    2010-07-01

    Energy dispersive X-ray fluorescence studies on determination of thorium (in the range of 7 to 137 mg/mL) in phosphoric acid solutions obtained by dissolution of thoria in autoclave were made. Fixed amounts of Y internal standard solutions, after dilution with equal amount of phosphoric acid, were added to the calibration as well as sample solutions. Solution aliquots of approximately 2-5 µL were deposited on thick absorbent sheets to absorb the solutions and the sheets were presented for energy dispersive X-ray fluorescence measurements. A calibration plot was made between intensity ratios (Th Lα/Y Kα) against respective amounts of thorium in the calibration solutions. Thorium amounts in phosphoric acid samples were determined using their energy dispersive X-ray fluorescence spectra and the above calibration plot. The energy dispersive X-ray fluorescence results, thus obtained, were compared with the corresponding gamma ray spectrometry results and were found to be within average deviation of 2.6% from the respective gamma ray spectrometry values. The average precision obtained in energy dispersive X-ray fluorescence determinations was found to be 4% (1 σ). The energy dispersive X-ray fluorescence method has an advantage over gamma ray spectrometry for thorium determination as the amount of sample required and measurement time is far less compared to that required in gamma ray spectrometry.

  17. Comparison of the radiological impacts of thorium and uranium nuclear fuel cycles

    SciTech Connect

    Meyer, H.R.; Witherspoon, J.P.; McBride, J.P.; Frederick, E.J.

    1982-03-01

    This report compares the radiological impacts of a fuel cycle in which only uranium is recycled, as presented in the Final Generic Environmental Statement on the Use of Recycle Plutonium in Mixed Oxide Fuel in Light Water Cooled Reactors (GESMO), with those of the light-water breeder reactor (LWBR) thorium/uranium fuel cycle in the Final Environmental Statement, Light Water Breeder Reactor Program. The significant offsite radiological impacts from routine operation of the fuel cycles result from the mining and milling of thorium and uranium ores, reprocessing spent fuel, and reactor operations. The major difference between the impacts from the two fuel cycles is the larger dose commitments associated with current uranium mining and milling operations as compared to thorium mining and milling. Estimated dose commitments from the reprocessing of either fuel type are small and show only moderate variations for specific doses. No significant differences in environmental radiological impact are anticipated for reactors using either of the fuel cycles. Radiological impacts associated with routine releases from the operation of either the thorium or uranium fuel cycles can be held to acceptably low levels by existing regulations.

  18. Recovery of uranium-233 from a thorium breeding blanket by pyrochemical techniques

    SciTech Connect

    Coops, M.S.; Knighton, J.B.

    1982-12-08

    We have carefully evaluated several processes that might be suitable for uranium recovery from thorium metal, and have chosen two that hold great promise. Both are simple non-aqueous methods that can readily be performed by remote means, and both require only a few simple process steps.

  19. Application of ICP-MS for the assessment of thorium excretion in urine.

    PubMed

    Roth, P; Werner, E; Wendler, I; Schramel, P

    1996-01-01

    A method for rapid and sensitive determination of thorium in urine by inductively coupled plasma mass spectometry (ICP-MS) is described. The method is sufficiently sensitive to detect 1 ng/L 232Th in urine without any sample preparation. The mean urinary 232Th excretion in 23 unexposed subjects was 6.2 +/- 3.3 ng/d.

  20. Accelerator-Driven Thorium-Cycle Fission:. Green Nuclear Power for the New Millennium

    NASA Astrophysics Data System (ADS)

    McIntyre, Peter; Sattarov, Akhdiyor

    2011-03-01

    In thorium-cycle fission, fast neutrons are used to transmute thorium to fissionable 233U and then stimulate fission. In accelerator-driven thorium-cycle fission (ADTC) the fast neutrons are produced by injecting a symmetric pattern of 7 energetic proton beams into a Pb spallation zone in the core. The fast neutrons are adiabatically moderated by the Pb so that they capture efficiently on 232Th, and fission heat is transferred via a convective Pb column above the core. The 7 proton beams are generated by a flux-coupled stack of isochronous cyclotrons. ADTC offers a green solution to the Earth's energy needs: the core operates as a sub-critical pile and cannot melt down; it eats its own long-lived fission products; a GW ADTC core can operate with uniform power density for a 7-year fuel cycle without shuffling fuel pins, and there are sufficient thorium reserves to run man's energy needs for the next 2000 years.

  1. Thorium colloid analysis by single particle inductively coupled plasma-mass spectrometry.

    PubMed

    Degueldre, C; Favarger, P-Y

    2004-04-19

    Thorium colloid analysis in water has been carried out by a single particle mode using inductively coupled plasma mass spectrometry (ICP-MS). The flash of ions due to the ionisation of a thorium colloidal particle in the plasma torch can be detected and measured in a time scan for (232)Th (+ ) or (248)[ThO] (+ ) according to the sensitivity required by the mass spectrometer. The peaks of the recorded intensity of the MS signal can be analysed as a function of the particle size or fraction of the studied element in the colloid phase. The frequency of the flashes is directly proportional to the concentration of particles in the colloidal suspension. After discussing Th colloid detection, on the basis of the intensity of the ion flashes generated in the plasma torch, tests were performed on thorium dioxide colloidal particles. This feasibility study also describes the experimental conditions and the limitation of the plasma design to detect thorium colloids in a single particle analysis mode down to about 10fg.

  2. Hydrothermal descriptive chemistry and single crystal structure determination of cesium and rubidium thorium fluorides.

    PubMed

    Underwood, Christopher C; Mann, Matthew; McMillen, Colin D; Kolis, Joseph W

    2011-11-21

    Two new cesium thorium fluorides and three new rubidium thorium fluorides have been synthesized hydrothermally and structurally characterized. The structures of two polymorphs of CsTh(3)F(13) are described in space group P6/mmm with a = 8.2608(14) and c = 8.6519(17) and space group Pmc2(1) with a = 8.1830(16), b = 7.5780(15), and c = 8.6244(17). The analogous orthorhombic compound RbTh(3)F(13), with a = 8.1805(16), b = 7.4378(15), and c = 8.6594(17) in space group Pmc2(1), is also reported. Two other rubidium thorium fluorides are also described: RbTh(2)F(9) crystallizes in the space group Pnma where a = 8.9101(18), b = 11.829(2), and c = 7.4048(15), and Rb(7)Th(6)F(31) crystallizes in the space group R3 where a = 15.609(2) and c = 10.823(2). Comparison of these materials was made on the basis of their structures and synthesis conditions. The formation of these species in hydrothermal fluids appears to be dependent upon the concentration of the alkali fluoride mineralizer solution and, thus, the ratio of alkali ions to thorium in the system.

  3. Retardation of uranium and thorium by a cementitious backfill developed for radioactive waste disposal.

    PubMed

    Felipe-Sotelo, M; Hinchliff, J; Field, L P; Milodowski, A E; Preedy, O; Read, D

    2017-07-01

    The solubility of uranium and thorium has been measured under the conditions anticipated in a cementitious, geological disposal facility for low and intermediate level radioactive waste. Similar solubilities were obtained for thorium in all media, comprising NaOH, Ca(OH)2 and water equilibrated with a cement designed as repository backfill (NRVB, Nirex Reference Vault Backfill). In contrast, the solubility of U(VI) was one order of magnitude higher in NaOH than in the remaining solutions. The presence of cellulose degradation products (CDP) results in a comparable solubility increase for both elements. Extended X-ray Absorption Fine Structure (EXAFS) data suggest that the solubility-limiting phase for uranium corresponds to a becquerelite-type solid whereas thermodynamic modelling predicts a poorly crystalline, hydrated calcium uranate phase. The solubility-limiting phase for thorium was ThO2 of intermediate crystallinity. No breakthrough of either uranium or thorium was observed in diffusion experiments involving NRVB after three years. Nevertheless, backscattering electron microscopy and microfocus X-ray fluorescence confirmed that uranium had penetrated about 40 μm into the cement, implying active diffusion governed by slow dissolution-precipitation kinetics. Precise identification of the uranium solid proved difficult, displaying characteristics of both calcium uranate and becquerelite. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. On the retention of uranyl and thorium ions from radioactive solution on peat moss.

    PubMed

    Humelnicu, Doina; Bulgariu, Laura; Macoveanu, Matei

    2010-02-15

    The efficiency of the radioactive uranyl and thorium ions on the peat moss from aqueous solutions has been investigated under different experimental conditions. The sorption and desorption of uranyl and thorium ions on three types (unmodified peat moss, peat moss treated with HNO(3) and peat moss treated with NaOH) of peat moss were studied by the static method. Peat moss was selected as it is available in nature, in any amount, as a cheap and accessible sorbent. Study on desorption of such ions led to the conclusion that the most favourable desorptive reagent for the uranyl ions is Na(2)CO(3) 1M while, for the thorium ions is HCl 1M. The results obtained show that the parameters here under investigation exercise a significant effect on the sorption process of the two ions. Also, the investigations performed recommend the peat moss treated with a base as a potential sorbent for the uranyl and thorium ions from a radioactive aqueous solution.

  5. Uranium and thorium sequential separation from norm samples by using a SIA system.

    PubMed

    Mola, M; Nieto, A; Peñalver, A; Borrull, F; Aguilar, C

    2014-01-01

    This study presents a sequential radiochemical separation method for uranium and thorium isotopes using a novel Sequential Injection Analysis (SIA) system with an extraction chromatographic resin (UTEVA). After the separation, uranium and thorium isotopes have been quantified by using alpha-particle spectrometry. The developed method has been tested by analyzing an intercomparison sample (phosphogypsum sample) from International Atomic Energy Agency (IAEA) with better recoveries for uranium and thorium than the obtained by using a classical method (93% for uranium using the new methodology and 82% with the classical method, and in the case of thorium the recoveries were 70% for the semi-automated method and 60% for the classical strategy). Afterwards, the method was successfully applied to different Naturally Occurring Radioactive Material (NORM) samples, in particular sludge samples taken from a drinking water treatment plant (DWTP) and also sediment samples taken from an area of influence of the dicalcium phosphate (DCP) factory located close to the Ebro river reservoir in Flix (Catalonia). The obtained results have also been compared with the obtained by the classical method and from that comparison it has been demonstrated that the presented strategy is a good alternative to existing methods offering some advantages as minimization of sample handling, reduction of solvents volume and also an important reduction of the time per analysis.

  6. Closed fuel cycle with increased fuel burn-up and economy applying of thorium resources

    NASA Astrophysics Data System (ADS)

    Kulikov, G. G.; Apse, V. A.

    2017-01-01

    The possible role of existing thorium reserves in the Russian Federation on engaging thorium in being currently closed (U-Pu)-fuel cycle of nuclear power of the country is considered. The application efficiency of thermonuclear neutron sources with thorium blanket for the economical use of existing thorium reserves is demonstrated. The aim of the work is to find solutions of such major tasks as the reduction of both front-end and back-end of nuclear fuel cycle and an enhancing its protection against the uncontrolled proliferation of fissile materials by means of the smallest changes in the fuel cycle. During implementation of the work we analyzed the results obtained earlier by the authors, brought new information on the number of thorium available in the Russian Federation and made further assessments. On the basis of proposal on the inclusion of hybrid reactors with Th-blanket into the future nuclear power for the production of light uranium fraction 232+233+234U, and 231Pa, we obtained the following results: 1. The fuel cycle will shift from fissile 235U to 233U which is more attractive for thermal power reactors. 2. The light uranium fraction is the most "protected" in the uranium component of fuel and mixed with regenerated uranium will in addition become a low enriched uranium fuel, that will weaken the problem of uncontrolled proliferation of fissile materials. 3. 231Pa doping into the fuel stabilizes its multiplying properties that will allow us to implement long-term fuel residence time and eventually to increase the export potential of all nuclear power technologies. 4. The thorium reserves being near city Krasnoufimsk (Russia) are large enough for operation of large-scale nuclear power of the Russian Federation of 70 GWe capacity during more than a quarter century under assumption that thorium is loaded into blankets of hybrid TNS only. The general conclusion: the inclusion of a small number of hybrid reactors with Th-blanket into the future nuclear

  7. Poumon du puisatier

    PubMed Central

    Elidrissi, Amal Moustarhfir; Zaghba, Nahid; Benjelloun, Hanane; Yassine, Najiba

    2016-01-01

    Le puisatier a pour profession le creusement et l'entretien des puits pour fournir de l'eau. Il est au contact de divers minerais, particulièrement la silice, particule qui présente un risque certain de développement des maladies pulmonaires connues sous le nom de silicose. Le but de notre travail est de préciser le profil épidémiologique, clinique, radiologique et évolutif des patients puisatiers silicotiques. C'est une étude rétrospective concernant 54 cas de puisatiers ayant une silicose, colligés au service des maladies respiratoires du CHU Ibn Rochd de Casablanca, de Mars 1997 à Janvier 2016. Tous les malades étaient des puisatiers, de sexe masculin, avec une moyenne d'âge de 50 ans. Le tabagisme était retrouvé dans 36 cas et un antécédent de tuberculose était noté dans huit cas. La radiographie thoracique retrouvait des grandes opacités dans 39 cas, des petites opacités dans 15 cas, et un épaississement des septats dans 11 cas. Ce tableau de silicose s'était compliqué d'une surinfection bactérienne dans 37% des cas, d' un pneumothorax dans 4% des cas et d'une tuberculose dans 20% des cas. La prise en charge thérapeutique était celle des complications. La déclaration de la maladie professionnelle et de l'indemnisation était faite. L'évolution était bonne dans 12 cas, stationnaire dans 17 cas et mauvaise dans 16 cas. La silicose est une pneumoconiose fréquente chez les puisatiers. Elle retentit sur la fonction respiratoire. Nous soulignons l'association fréquente de tuberculose et nous insistons sur la prévention qui reste le meilleur traitement. PMID:28292119

  8. Mechanisms of magma generation beneath hawaii and mid-ocean ridges: uranium/thorium and samarium/neodymium isotopic evidence.

    PubMed

    Sims, K W; Depaolo, D J; Murrell, M T; Baldridge, W S; Goldstein, S J; Clague, D A

    1995-01-27

    Measurements of uranium/thorium and samarium/neodymium isotopes and concentrations in a suite of Hawaiian basalts show that uranium/thorium fractionation varies systematically with samarium/neodymium fractionation and major-element composition; these correlations can be understood in terms of simple batch melting models with a garnet-bearing peridotite magma source and melt fractions of 0.25 to 6.5 percent. Midocean ridge basalts shows a systematic but much different relation between uranium/thorium fractionation and samarium/neodymium fractionation, which, although broadly consistent with melting of a garnet-bearing peridotite source, requires a more complex melting model.

  9. ORNL experience and perspectives related to processing of thorium and 233U for nuclear fuel

    SciTech Connect

    Croff, Allen G.; Collins, Emory D.; Del Cul, G. D.; Wymer, R. G.; Krichinsky, Alan M.; Spencer, B. B.; Patton, Brad D.

    2016-05-01

    Thorium-based nuclear fuel cycles have received renewed attention in both research and public circles since about the year 2000. Much of the attention has been focused on nuclear fission energy production that utilizes thorium as a fertile element for producing fissionable 233U for recycle in thermal reactors, fast reactors, or externally driven systems. Here, lesser attention has been paid to other fuel cycle operations that are necessary for implementation of a sustainable thorium-based fuel cycle such as reprocessing and fabrication of recycle fuels containing 233U.

  10. ORNL experience and perspectives related to processing of thorium and 233U for nuclear fuel

    SciTech Connect

    Croff, Allen G.; Collins, Emory D.; Del Cul, G. D.; Wymer, R. G.; Krichinsky, Alan M.; Spencer, B. B.; Patton, Brad D.

    2016-05-01

    Thorium-based nuclear fuel cycles have received renewed attention in both research and public circles since about the year 2000. Much of the attention has been focused on nuclear fission energy production that utilizes thorium as a fertile element for producing fissionable 233U for recycle in thermal reactors, fast reactors, or externally driven systems. Here, lesser attention has been paid to other fuel cycle operations that are necessary for implementation of a sustainable thorium-based fuel cycle such as reprocessing and fabrication of recycle fuels containing 233U.

  11. Depletion Analysis of Modular High Temperature Gas-cooled Reactor Loaded with LEU/Thorium Fuel

    SciTech Connect

    Sonat Sen; Gilles Youinou

    2013-02-01

    Thorium based fuel has been considered as an option to uranium-based fuel, based on considerations of resource utilization (Thorium is more widely available when compared to Uranium). The fertile isotope of Thorium (Th-232) can be converted to fissile isotope U-233 by neutron capture during the operation of a suitable nuclear reactor such as High Temperature Gas-cooled Reactor (HTGR). However, the fertile Thorium needs a fissile supporter to start and maintain the conversion process such as U-235 or Pu-239. This report presents the results of a study that analyzed the thorium utilization in a prismatic HTGR, namely Modular High Temperature Gas-Cooled Reactor (MHTGR) that was designed by General Atomics (GA). The collected for the modeling of this design come from Chapter 4 of MHTGR Preliminary Safety Information Document that GA sent to Department of Energy (DOE) on 1995. Both full core and unit cell models were used to perform this analysis using SCALE 6.1 and Serpent 1.1.18. Because of the long mean free paths (and migration lengths) of neutrons in HTRs, using a unit cell to represent a whole core can be non-trivial. The sizes of these cells were set to match the spectral index between unit cell and full core domains. It was found that for the purposes of this study an adjusted unit cell model is adequate. Discharge isotopics and one-group cross-sections were delivered to the transmutation analysis team. This report provides documentation for these calculations

  12. Annular seed-blanket thorium fuel core concepts for heavy water moderated reactors

    SciTech Connect

    Bromley, B.P.; Hyland, B.

    2013-07-01

    New reactor concepts to implement thorium-based fuel cycles have been explored to achieve maximum resource utilization. Pressure tube heavy water reactors (PT-HWR) are highly advantageous for implementing the use of thorium-based fuels because of their high neutron economy and on-line re-fuelling capability. The use of heterogeneous seed-blanket core concepts in a PT-HWR where higher-fissile-content seed fuel bundles are physically separate from lower-fissile-content blanket bundles allows more flexibility and control in fuel management to maximize the fissile utilization and conversion of fertile fuel. The lattice concept chosen is a 35-element bundle made with a homogeneous mixture of reactor grade Pu and Th, and with a central zirconia rod to help reduce coolant void reactivity. Several annular heterogeneous seed-blanket core concepts with plutonium-thorium-based fuels in a 700-MWe-class PT-HWR were analyzed, using a once-through thorium (OTT) cycle. Different combinations of seed and blanket fuel were tested to determine the impact on core-average burnup, fissile utilization, power distributions, and other performance parameters. It was found that the various core concepts can achieve a fissile utilization that is up to 30% higher than is currently achieved in a PT-HWR using conventional natural uranium fuel bundles. Up to 67% of the Pu is consumed; up to 43% of the energy is produced from thorium, and up to 363 kg/year of U-233 is produced. Seed-blanket cores with ∼50% content of low-power blanket bundles may require power de-rating (∼58% to 65%) to avoid exceeding maximum limits for peak channel power, bundle power and linear element ratings. (authors)

  13. Checkerboard seed-blanket thorium fuel core concepts for heavy water moderated reactors

    SciTech Connect

    Bromley, B.P.; Hyland, B.

    2013-07-01

    New reactor concepts to implement thorium-based fuel cycles have been explored to achieve maximum resource utilization. Pressure tube heavy water reactors (PT-HWR) are highly advantageous for implementing the use of thorium-based fuels because of their high neutron economy and on-line re-fuelling capability. The use of heterogeneous seed-blanket core concepts in a PT-HWR where higher-fissile-content seed fuel bundles are physically separate from lower-fissile-content blanket bundles allows more flexibility and control in fuel management to maximize the fissile utilization and conversion of fertile fuel. The lattice concept chosen was a 35-element bundle made with a homogeneous mixture of reactor grade Pu (about 67 wt% fissile) and Th, and with a central zirconia rod to help reduce coolant void reactivity. Several checkerboard heterogeneous seed-blanket core concepts with plutonium-thorium-based fuels in a 700-MWe-class PT-HWR were analyzed, using a once-through thorium (OTT) cycle. Different combinations of seed and blanket fuel were tested to determine the impact on core-average burnup, fissile utilization, power distributions, and other performance parameters. It was found that various checkerboard core concepts can achieve a fissile utilization that is up to 26% higher than that achieved in a PT-HWR using more conventional natural uranium fuel bundles. Up to 60% of the Pu is consumed; up to 43% of the energy is produced from thorium, and up to 303 kg/year of Pa-233/U-233/U-235 are produced. Checkerboard cores with about 50% of low-power blanket bundles may require power de-rating (65% to 74%) to avoid exceeding maximum limits for channel and bundle powers and linear element ratings. (authors)

  14. Thorium isotopes in colloidal fraction of water from San Marcos Dam, Chihuahua, Mexico

    NASA Astrophysics Data System (ADS)

    Cabral-Lares, M.; Melgoza, A.; Montero-Cabrera, M. E.; Renteria-Villalobos, M.

    2013-07-01

    The main interest of this stiidy is to assess the contents and distribution of Th-series isotopes in colloidal fraction of surface water from San Marcos dam, because the suspended particulate matter serves as transport medium for several pollutants. The aim of this work was to assess the distribution of thorium isotopes (232Th and 230Th) contained in suspended matter. Samples were taken from three surface points along the San Marcos dam: water input, midpoint, and near to dam wall. In this last point, a depth sampling was also carried out. Here, three depth points were taken at 0.4, 8 and 15 meters. To evaluate the thorium behavior in surface water, from every water sample the colloidal fraction was separated, between 1 and 0.1 μm. Thorium isotopes concentraron in samples were obtained by alpha spectrometry. Activity concentrations obtained of 232Th and 230Th in surface points ranged from 0.3 to 0.5 Bq ṡ L-1, whereas in depth points ranged from 0.4 to 3.2 Bq ṡ L-1, respectively. The results show that 230Th is in higher concentration than 232Th in colloidal fraction. This can be attributed to a preference of these colloids to adsorb uranium. Thus, the activity ratio 230Th/232Th in colloidal fraction showed values from 2.3 to 10.2. In surface points along the dam, 230Th activity concentration decreases while 232Th concentration remains constant. On the other hand, activity concentrations of both isotopes showed a pointed out enhancement with depth. The results have shown a possible lixiviation of uranium from geological substrate into the surface water and an important fractionation of thorium isotopes, which suggest that thorium is non-homogeneously distributed along San Marcos dam.

  15. Du Pont Information Flow System

    ERIC Educational Resources Information Center

    Hoffman, Warren S.

    1972-01-01

    The Information Flow System is a large-scale information retrieval system developed for processing of Du Pont information files. As currently implemented, the system stores and retrieves information on company technical reports. Extensions of the system for handling chemical structure information and on-line processing are also discussed. (3…

  16. Rupture sous-cutanée du tendon long extenseur du pouce: à propos de 5 cas

    PubMed Central

    Abdelillah, Rachid; Abbassi, Najib; Erraji, Moncef; Abdeljawad, Najib; Yacoubi, Hicham; Daoudi, Abdelkrim

    2014-01-01

    La rupture spontanée du muscle long extenseur du pouce (EPL) du tendon au niveau du poignet est rare et principalement rapportés après fracture du radius distal à tubercule de Lister, dans la synovite, ténosynovite ou la polyarthrite rhumatoïde. Nous rapportons 5 cas de rupture spontanée du tendon long extenseur du pouce, traités par une greffe ou un transfert tendineux. PMID:25317233

  17. Study of a multi-beam accelerator driven thorium reactor

    SciTech Connect

    Ludewig, H.; Aronson, A.

    2011-03-01

    be supplying source neutrons. The proton beam will be assumed to have an energy of 1 GeV, and the target material will be natural lead, which will also be the coolant for the reactor assembly. Three proton beam arrangements will be considered, first a single beam (the traditional arrangement) with an entry at the assembly center, two more options will consist of three and six entry locations. The reactor fuel assembly parameters will be based on those of the S-PRISM fast reactor proposed by GE, and the fuel composition and type will be based on that proposed by Aker Solutions for use in their accelerator driven thorium reactor. The following table summarizes the parameters to be used in this study. The isotopic composition of the fertile material is 100% Th-232, and the plutonium isotopic distribution corresponds to that characteristic of the discharge from a typical LWR, following five years of decay. Thus, the isotopic distribution for the plutonium is; Pu-238 2.5%, Pu-239 53.3%, Pu-240 25.1%, Pu-241 11.8%, and Pu-242 7.3%.

  18. Systematic studies of early actinide complexes: thorium(IV) fluoroketimides.

    PubMed

    Schelter, Eric J; Yang, Ping; Scott, Brian L; Re, Ryan E Da; Jantunen, Kimberly C; Martin, Richard L; Hay, P Jeffrey; Morris, David E; Kiplinger, Jaqueline L

    2007-04-25

    Reaction of (C5Me5)2Th(CH3)2 with 2 equiv of NC-ArF gives the corresponding fluorinated thorium(IV) bis(ketimide) complexes (C5Me5)2Th[-N=C(CH3)(ArF)]2 (where ArF = 3-F-C6H4 (4), 4-F-C6H4 (5), 2-F-C6H4 (6), 3,5-F2-C6H3 (7), 3,4,5-F3-C6H2 (8), 2,6-F2-C6H3 (9), 2,4,6-F3-C6H2 (10), and C6F5 (11)). The complexes have been characterized by a combination of single-crystal X-ray diffraction, cyclic voltammetry and NMR, and UV-visible absorption and low-temperature luminescence spectroscopies. Density functional theory (DFT) and time-dependent DFT (TD-DFT) results are reported for complexes 5, 11, and (C5Me5)2Th[-N=C(Ph)2]2 (1) for comparison with experimental data and to guide in the interpretation of the spectroscopic results. The most significant structural perturbation imparted by the fluorine substitution in these complexes is a rotation of the fluorophenyl group (ArF) out of the plane defined by the N=C(CMe)(Cipso) fragment in complexes 9-11 when the ArF group possesses two ortho fluorine atoms. Excellent agreement is obtained between the optimized ground state DFT calculated structures and crystal structures for 11, which displays the distortion, as well as 5, which does not. In complexes 9-11, the out-of-plane rotation results in large interplanar angles (phi) between the planes formed by ketimide atoms N=C(CMe)(Cipso) and the ketimide aryl groups in the range phi = 49.1-88.8 degrees , while in complexes 5, 7, and 8, phi = 5.7-34.9 degrees . The large distortions in 9-11 are a consequence of an unfavorable steric interaction between one of the two ortho fluorine atoms and the methyl group [-N=C(CH3)] on the ketimide ligand. Excellent agreement is also observed between the experimental electronic spectroscopic data and the TD-DFT predictions that the two lowest lying singlet states are principally of nonbonding nitrogen p orbital to antibonding C=N pi* orbital (pN-->pi*C=N or npi*) character, giving rise to moderately intense transitions in the mid-visible spectral

  19. EPA Method EMSL-33: Isotopic Determination of Plutonium, Uranium, and Thorium in Water, Soil, Air, and Biological Tissue

    EPA Pesticide Factsheets

    SAM lists this method to provide for the analysis of isotopic plutonium, uranium and thorium, together or individually, in drinking water, aqueous/liquid, soil/sediment, surface wipe and/or air filter samples by alpha spectrometry.

  20. Continuous thorium biosorption--dynamic study for critical bed depth determination in a fixed-bed reactor.

    PubMed

    Picardo, Marta Cristina; Ferreira, Ana Cristina de Melo; da Costa, Antonio Carlos Augusto

    2009-01-01

    The objective of the work was to evaluate the biosorption of thorium by the seaweed Sargassum filipendula in a dynamic system. Different bed depths were tested with the purpose of evaluating the critical bed depth for total uptake of the radioactive element. Several bed depths were tested, ranging from 5.0 to 40.0 cm. Bed depths tested presented distinct capacities to accumulate thorium. An increase in biosorption efficiency was observed with an increase in bed depth. The 30.0 cm bed produced an effluent still containing detectable levels of thorium. The critical bed depth suitable for a complete removal of thorium by S.filipendula biomass was equal to 40.0 cm.

  1. Diffusion in thorium carbide: A first-principles study

    NASA Astrophysics Data System (ADS)

    Pérez Daroca, D.; Llois, A. M.; Mosca, H. O.

    2015-12-01

    The prediction of the behavior of Th compounds under irradiation is an important issue for the upcoming Generation-IV nuclear reactors. The study of self-diffusion and hetero-diffusion is a central key to fulfill this goal. As a first approach, we obtained, by means of first-principles methods, migration and activation energies of Th and C atoms self-diffusion and diffusion of He atoms in ThC. We also calculate diffusion coefficients as a function of temperature.

  2. Determination of uranium and thorium in complex samples using chromatographic separation, ICP-MS and spectrophotometric detection.

    PubMed

    Rozmarić, Martina; Ivsić, Astrid Gojmerac; Grahek, Zeljko

    2009-11-15

    The paper describes a research of possible application of UTEVA and TRU resins and anion exchanger AMBERLITE CG-400 in nitrate form for the isolation of uranium and thorium from natural samples. The results of determination of distribution coefficient have shown that uranium and thorium bind on TRU and UTEVA resins from the solutions of nitric and hydrochloric acids, and binding strength increases proportionally to increase the concentration of acids. Uranium and thorium bind rather strongly to TRU resin from the nitric acid in concentration ranging from 0.5 to 5 mol L(-1), while large quantities of other ions present in the sample do not influence on the binding strength. Due to the difference in binding strength in HCl and HNO(3) respectively, uranium and thorium can be easily separated from each other on the columns filled with TRU resin. Furthermore, thorium binds to anion exchanger in nitrate form from alcohol solutions of nitric acid very strongly, while uranium does not, so they can be easily separated. Based on these results, we have created the procedures of preconcentration and separation of uranium and thorium from the soil, drinking water and seawater samples by using TRU and UTEVA resins and strong base anion exchangers in nitrate form. In one of the procedures, uranium and thorium bind directly from the samples of drinking water and seawater on the column filled with TRU resin from 0.5 mol L(-1) HNO(3) in a water sample. After binding, thorium is separated from uranium with 0.5 mol L(-1) HCl, and uranium is eluted with deionised water. By applying the described procedure, it is possible to achieve the concentration factor of over 1000 for the column filled with 1g of resin and splashed with 2L of the sample. Spectrophotometric determination with Arsenazo III, with this concentration factor results in detection limits below 1 microg L(-1) for uranium and thorium. In the second procedure, uranium and thorium are isolated from the soil samples with TRU

  3. Sorption and coprecipitation of trace concentrations of thorium with various minerals under conditions simulating an acid uranium mill effluent environment

    USGS Publications Warehouse

    Landa, Edward R.; Le, Anh H.; Luck, Rudy L.; Yeich, Philip J.

    1995-01-01

    Sorption of thorium by pre-existing crystals of anglesite (PbSO4), apatite (Ca5(PO4)3(HO)), barite (BaSO4), bentonite (Na0.7Al3.3Mg0.7Si8O20(OH)4), celestite (SrSO4), fluorite (CaF2), galena (PbS), gypsum (CaSO4·2H2O), hematite (Fe2O3), jarosite (KFe3(SO4)2(OH)6), kaolinite (Al2O3·2SiO2·2H2O), quartz (SiO2) and sodium feldspar (NaAlSi3O8) was studied under conditions that simulate an acidic uranium mill effluent environment. Up to 100% removal of trace quantitiees of thorim (approx. 1.00 ppm in 0.01 N H2SO4) from solution occurred within 3 h with fluorite and within 48 h in the case of bentonite. Quartz, jarosite, hematite, sodium feldspar, gypsum and galena removed less than 15% of the thorium from solution. In the coprecipitation studies, barite, anglesite, gypsum and celestite were formed in the presence of thorium (approx. 1.00 ppm). Approximately all of the thorium present in solution coprecipitated with barite and celestite; 95% coprecipitated with anglesite and less than 5% with gypsum under similar conditions. When jarosite was precipitated in the presence of thorium, a significant amount of thorium (78%) was incorporated in the precipitate.

  4. Analysis of thorium-salted fuels to improve uranium utilization in the once-through fuel cycle

    SciTech Connect

    Eschbach, E.A.; Merrill, E.T.; Prichard, A.W.

    1981-09-01

    Calculations and analyses indicate that no improvement can be achieved in uranium utilization for the once-through LWR fuel cycle over use of slightly enriched uranium by employing thorium distributed with uranium. The study included thorium additions: (1) slight amounts, (2) larger amounts, in either intimately mixed or in duplex pellets, (3) in spectrally shifted or not spectrally shifted reactors, and (4) in three- or five-year reactivity limited exposures. While thorium-uranium combinations improves the initial conversion ratio, the reactivity lifetime was not extended enough to override the additional uranium required. The effective fission cross-section of the bred /sup 233/U relative to /sup 239/Pu's in typical LWR neutron spectra is not large enough for /sup 233/U to make as great a contribution to end-of-life reactivity as /sup 239/Pu in a slightly enriched uranium fuel element. /sup 233/U's reactivity contribution relative to /sup 239/Pu's is lower in fuel configurations such as slightly enriched uranium LWR fuel loads. On the other hand, /sup 233/U's reactivity contribution appears more positive for reactors that involve lower average concentrations of thermal neutron absorbers. If /sup 238/U-thorium fuels reprocessed, the recovered /sup 233/U would increase uranium utilization, but may not reduce fuel cycle costs. The thorium-salted fuels exhibit substantially flatter reactivity characteristics with exposure time. Spectral shift helped the utilization of uranium and thorium.

  5. L'Aventure du LHC

    ScienceCinema

    None

    2016-07-12

    Cette présentation s’adressera principalement aux personnes qui ont construit le LHC. La construction du LHC fut longue et difficile. De nombreux problèmes sont apparus en cours de route. Tous ont été résolus grâce au dévouement et à l’engagement du personnel et des collaborateurs. Je reviendrai sur les coups durs et les réussites qui ont marqués ces 15 dernières années et je vous montrerai combien cette machine, le fruit de vos efforts, est extraordinaire.

  6. Phytosanitary Irradiation

    PubMed Central

    Hallman, Guy J.; Blackburn, Carl M.

    2016-01-01

    Phytosanitary treatments disinfest traded commodities of potential quarantine pests. Phytosanitary irradiation (PI) treatments use ionizing radiation to accomplish this, and, since their international commercial debut in 2004, the use of this technology has increased by ~10% annually. Generic PI treatments (one dose is used for a group of pests and/or commodities, although not all have been tested for efficacy) are used in virtually all commercial PI treatments, and new generic PI doses are proposed, such as 300 Gy, for all insects except pupae and adult Lepidoptera (moths). Fresh fruits and vegetables tolerate PI better than any other broadly used treatment. Advances that would help facilitate the use of PI include streamlining the approval process, making the technology more accessible to potential users, lowering doses and broadening their coverage, and solving potential issues related to factors that might affect efficacy. PMID:28231103

  7. Uranium and thorium sorption on minerals studied by x-ray absorption spectroscopy

    SciTech Connect

    Hudson, E.A.; Terminello, L.J.; Viani, B.E.

    1995-12-01

    Several actinide-mineral sorption systems were studied by uranium and thorium L{sub 3}-edge x-ray absorption spectroscopy. A series of layer silicate minerals, including micas, were selected for their systematic variations in surface structure, e.g. degree of permanent negative charge on the basal planes. An expansible layer silicate, vermiculite, was treated to provide several different interlayer spacings, allowing variations in the accessibility of interior cation exchange sites. The finely powdered minerals were exposed to aqueous solutions of uranyl chloride or thorium chloride. Analysis of the EXAFS and XANES spectra indicates the influence of the mineral substrate upon the local structure of the bound actinide species. Trends in the data are interpreted based upon the known variations in mineral structure.

  8. Simulation on reactor TRIGA Puspati core kinetics fueled with thorium (Th) based fuel element

    SciTech Connect

    Mohammed, Abdul Aziz Rahman, Shaik Mohmmed Haikhal Abdul; Pauzi, Anas Muhamad Zin, Muhamad Rawi Muhammad; Jamro, Rafhayudi; Idris, Faridah Mohamad

    2016-01-22

    In confronting global energy requirement and the search for better technologies, there is a real case for widening the range of potential variations in the design of nuclear power plants. Smaller and simpler reactors are attractive, provided they can meet safety and security standards and non-proliferation issues. On fuel cycle aspect, thorium fuel cycles produce much less plutonium and other radioactive transuranic elements than uranium fuel cycles. Although not fissile itself, Th-232 will absorb slow neutrons to produce uranium-233 ({sup 233}U), which is fissile. By introducing Thorium, the numbers of highly enriched uranium fuel element can be reduced while maintaining the core neutronic performance. This paper describes the core kinetic of a small research reactor core like TRIGA fueled with a Th filled fuel element matrix using a general purpose Monte Carlo N-Particle (MCNP) code.

  9. Simulation on reactor TRIGA Puspati core kinetics fueled with thorium (Th) based fuel element

    NASA Astrophysics Data System (ADS)

    Mohammed, Abdul Aziz; Pauzi, Anas Muhamad; Rahman, Shaik Mohmmed Haikhal Abdul; Zin, Muhamad Rawi Muhammad; Jamro, Rafhayudi; Idris, Faridah Mohamad

    2016-01-01

    In confronting global energy requirement and the search for better technologies, there is a real case for widening the range of potential variations in the design of nuclear power plants. Smaller and simpler reactors are attractive, provided they can meet safety and security standards and non-proliferation issues. On fuel cycle aspect, thorium fuel cycles produce much less plutonium and other radioactive transuranic elements than uranium fuel cycles. Although not fissile itself, Th-232 will absorb slow neutrons to produce uranium-233 (233U), which is fissile. By introducing Thorium, the numbers of highly enriched uranium fuel element can be reduced while maintaining the core neutronic performance. This paper describes the core kinetic of a small research reactor core like TRIGA fueled with a Th filled fuel element matrix using a general purpose Monte Carlo N-Particle (MCNP) code.

  10. Advantages of liquid fluoride thorium reactor in comparison with light water reactor

    NASA Astrophysics Data System (ADS)

    Bahri, Che Nor Aniza Che Zainul; Majid, Amran Ab.; Al-Areqi, Wadeeah M.

    2015-04-01

    Liquid Fluoride Thorium Reactor (LFTR) is an innovative design for the thermal breeder reactor that has important potential benefits over the traditional reactor design. LFTR is fluoride based liquid fuel, that use the thorium dissolved in salt mixture of lithium fluoride and beryllium fluoride. Therefore, LFTR technology is fundamentally different from the solid fuel technology currently in use. Although the traditional nuclear reactor technology has been proven, it has perceptual problems with safety and nuclear waste products. The aim of this paper is to discuss the potential advantages of LFTR in three aspects such as safety, fuel efficiency and nuclear waste as an alternative energy generator in the future. Comparisons between LFTR and Light Water Reactor (LWR), on general principles of fuel cycle, resource availability, radiotoxicity and nuclear weapon proliferation shall be elaborated.

  11. Study on Equilibrium Characteristics of Thorium-Plutonium-Minor Actinides Mixed Oxides Fuel in PWR

    SciTech Connect

    Waris, A.; Permana, S.; Kurniadi, R.; Su'ud, Z.; Sekimoto, H.

    2010-06-22

    A study on characteristics of thorium-plutonium-minor actinides utilization in the pressurized water reactor (PWR) with the equilibrium burnup model has been conducted. For a comprehensive evaluation, several fuel cycles scenario have been included in the present study with the variation of moderator-to-fuel volume ratio (MFR) of PWR core design. The results obviously exhibit that the neutron spectra grow to be harder with decreasing of the MFR. Moreover, the neutron spectra also turn into harder with the rising number of confined heavy nuclides. The required {sup 233}U concentration for criticality of reactor augments with the increasing of MFR for all heavy nuclides confinement and thorium and uranium confinement in PWR.

  12. Advantages of liquid fluoride thorium reactor in comparison with light water reactor

    SciTech Connect

    Bahri, Che Nor Aniza Che Zainul Majid, Amran Ab.; Al-Areqi, Wadeeah M.

    2015-04-29

    Liquid Fluoride Thorium Reactor (LFTR) is an innovative design for the thermal breeder reactor that has important potential benefits over the traditional reactor design. LFTR is fluoride based liquid fuel, that use the thorium dissolved in salt mixture of lithium fluoride and beryllium fluoride. Therefore, LFTR technology is fundamentally different from the solid fuel technology currently in use. Although the traditional nuclear reactor technology has been proven, it has perceptual problems with safety and nuclear waste products. The aim of this paper is to discuss the potential advantages of LFTR in three aspects such as safety, fuel efficiency and nuclear waste as an alternative energy generator in the future. Comparisons between LFTR and Light Water Reactor (LWR), on general principles of fuel cycle, resource availability, radiotoxicity and nuclear weapon proliferation shall be elaborated.

  13. Optimization of small long-life PWR based on thorium fuel

    NASA Astrophysics Data System (ADS)

    Subkhi, Moh Nurul; Suud, Zaki; Waris, Abdul; Permana, Sidik

    2015-09-01

    A conceptual design of small long-life Pressurized Water Reactor (PWR) using thorium fuel has been investigated in neutronic aspect. The cell-burn up calculations were performed by PIJ SRAC code using nuclear data library based on JENDL 3.2, while the multi-energy-group diffusion calculations were optimized in three-dimension X-Y-Z geometry of core by COREBN. The excess reactivity of thorium nitride with ZIRLO cladding is considered during 5 years of burnup without refueling. Optimization of 350 MWe long life PWR based on 5% 233U & 2.8% 231Pa, 6% 233U & 2.8% 231Pa and 7% 233U & 6% 231Pa give low excess reactivity.

  14. Micro-column solid phase extraction to determine uranium and thorium in environmental samples.

    PubMed

    Tsai, Tsuey-Lin; Lin, Chun-Chih; Chu, Tieh-Chi

    2008-08-01

    Extraction chromatographic separation techniques based on U/TEVA and TEVA resins were utilized to separate uranium and thorium isotopes in complex matrices from environmental samples. This approach has the advantages of ease of quantitative analysis, small sample size, an absence of mixed waste solvents, complete separation of U/Th isotopes, acceptable chemical yields and good energy resolution in the alpha spectrum. The procedure for analyzing alpha-emitting isotopes of uranium and thorium in geothermal water from Peito, Taiwan, is illustrated in detail. It involves sample pre-concentration, filtration and separation by highly selective extraction chromatographic resins, followed by electroplating and alpha-spectroscopy. The analytical results show a chemical recovery exceeding 55% for U and 65% for Th, respectively, under optimized conditions. The efficient and cost-effective use of recyclable columns makes the analytical methods simple, accurate, rapid, reliable and robust.

  15. Dosimetric assessment from 212Pb inhalation at a thorium purification plant.

    PubMed

    Campos, M P; Pecequilo, B R S

    2004-01-01

    At the Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, Brazil, there is a facility (thorium purification plant) where materials with high thorium concentrations are manipulated. In order to estimate afterwards the lung cancer risk for the workers, the thoron daughter (212Pb) levels were assessed and the committed effective and lung committed equivalent doses for workers in place. A total of 28 air filter samples were measured by total alpha counting through the modified Kusnetz method, to determine the 212Pb concentraion. The committed effective dose and lung committed equivalent dose due to 212Pb inhalation were derived from compartmental analysis following the ICRP 66 lung compartmental model, and ICRP 67 lead metabolic model.

  16. Determination of the Galaxy age by the method of uranium-thorium-plutonium isotopic ratios

    NASA Astrophysics Data System (ADS)

    Panov, I. V.; Lutostansky, Yu. S.; Eichler, M.; Thielemann, F.-K.

    2017-07-01

    The dependence of the Galaxy age ( T G), as determined by the method of uranium-thorium isotopic ratios, on the parameters of the nucleosynthesis model is studied within the theory of galactic nucleosynthesis. It is shown that TG depends strongly both on the scenario of the production of nuclei in the r-process and those features of neutron-rich nuclei that are used in the respective analysis and on galactic-nucleosynthesis parameters. The effect of a sudden nucleosynthesis spike before the formation of a solar system on the Galaxy age is evaluated. The region of admissible values of the parameters of galacticnucleosynthesis theory is discussed. The method of uranium-thorium isotopic ratios is supplemented with the 244Pu/238U ratio for yet another cosmochronometer pair, and the Galaxy age is estimated on the basis of the model modified in this way.

  17. Thorium accumulation in the sedimentary environment of the Vigo Ria (NW Iberian Peninsula).

    PubMed

    Marmolejo-Rodríguez, Ana J; Caetano, Miguel; Prego, Ricardo; Vale, Carlos

    2008-10-01

    Thorium levels and their association with Fe, Sc, Ca, and Particulate Organic Carbon (POC) were researched in sediments of the Vigo Ria in order to assess the influence of radioactive gneisses from the neighbouring continental Galiñeiro Complex. Sediment of 50 surface samples and 1 core was analysed by ICP-MS and the results were validated with certificate reference material from marine sediment. It was found that Th accumulates in the middle Ria zone (9-15 mg kg(-1)) as a result of the terrestrial source. The thorium concentration in the Ria (average: 9.4+/-5.1 mg kg(-1)) is not anthropogenically impacted in accordance with its own regional background level (11.4+/-3.5 mg kg(-1)), which is two times higher than the content in earth's crust. Throughout the relationship Th/Fe, Th may be associated with the iron cycle in the Ria, probably through iron oxy-hydroxide scavenging.

  18. Thorium nanochemistry: the solution structure of the Th(IV)-hydroxo pentamer.

    PubMed

    Walther, Clemens; Rothe, Jörg; Schimmelpfennig, Bernd; Fuss, Markus

    2012-08-28

    Tetravalent thorium exhibits a strong tendency towards hydrolysis and subsequent polymerization. Polymeric species play a crucial role in understanding thorium solution chemistry, since their presence causes apparent solubility several orders of magnitude higher than predicted by thermodynamic data bases. Although electrospray mass spectrometry (ESI MS) identifies Th(IV) dimers and pentamers unequivocally as dominant species close to the solubility limit, the molecular structure of Th(5)(OH)(y) polymers was hitherto unknown. In the present study, X-ray absorption fine structure (XAFS) spectroscopy, high energy X-ray scattering (HEXS) measurements, and quantum chemical calculations are combined to solve the pentamer structure. The most favourable structure is represented by two Th(IV) dimers linked by a central Th(IV) cation through hydroxide bridges.

  19. Electrotransport and diffusivity of molybdenum, rhenium, tungsten, and zirconium in beta-thorium

    NASA Technical Reports Server (NTRS)

    Schmidt, F. A.; Beck, M. S.; Rehbein, D. K.; Conzemius, R. J.; Carlson, O. N.

    1984-01-01

    The electric mobilities, diffusivities, and effective valences were determined for molybdenum, rhenium, tungsten, and zirconium in beta-thorium. All four solutes migrated in the same direction as the electron flow. Rhenium and molybdenum were found to be very mobile, with tungsten somewhat slower. Zirconium was found to move at a rate near that of the self-diffusion of beta-thorium, viz., about 10 to the -11th sq m/s at 1500 C. The electromigration velocities showed a similar trend. A comparison was made between experimental data obtained by scanning laser mass spectrometry and theoretical transport equations for two purification experiments. Good agreement was obtained with both the concentration profile predicted by DeGroot and the purification ratio predicted by Verhoeven.

  20. An open-framework thorium sulfate hydrate with 11.5 A voids.

    PubMed

    Wilson, Richard E; Skanthakumar, S; Knope, Karah E; Cahill, Christopher L; Soderholm, L

    2008-10-20

    We report the synthesis of a thorium sulfate hydrate with 11.5 A open channels that propagate through the structure. The compound crystallizes in the tetragonal space group P4(2)/nmc, a = b = 25.890(4) A, c = 9.080(2) A, Z = 8, V = 6086.3(2) A(3). The thermal stability of the compound was investigated using thermogravimetric analysis and high-energy X-ray scattering (HEXS) revealing that the compound begins to undergo decomposition near 200 degrees C with an accompanied loss in crystallinity. The immediate coordination environment about the thorium atoms remains intact through heating to 500 degrees C as demonstrated by HEXS. Further heating reveals the formation of at least two crystalline phases, Th(SO4)2 and ThO2, which ultimately decompose to ThO2.

  1. Uranium- and thorium-doped graphene for efficient oxygen and hydrogen peroxide reduction.

    PubMed

    Sofer, Zdeněk; Jankovský, Ondřej; Šimek, Petr; Klímová, Kateřina; Macková, Anna; Pumera, Martin

    2014-07-22

    Oxygen reduction and hydrogen peroxide reduction are technologically important reactions in the fields of energy generation and sensing. Metal-doped graphenes, where metal serves as the catalytic center and graphene as the high area conductor, have been used as electrocatalysts for such applications. In this paper, we investigated the use of uranium-graphene and thorium-graphene hybrids prepared by a simple and scalable method. The hybrids were synthesized by the thermal exfoliation of either uranium- or thorium-doped graphene oxide in various atmospheres. The synthesized graphene hybrids were characterized by high-resolution XPS, SEM, SEM-EDS, combustible elemental analysis, and Raman spectroscopy. The influence of dopant and exfoliation atmosphere on electrocatalytic activity was determined by electrochemical measurements. Both hybrids exhibited excellent electrocatalytic properties toward oxygen and hydrogen peroxide reduction, suggesting that actinide-based graphene hybrids have enormous potential for use in energy conversion and sensing devices.

  2. Thorium nanochemistry: the solution structure of the Th(IV)-hydroxo pentamer

    SciTech Connect

    Walther, Clemens; Rothe, Jörg; Schimmelpfennig, Bernd; Fuss, Markus

    2012-10-10

    Tetravalent thorium exhibits a strong tendency towards hydrolysis and subsequent polymerization. Polymeric species play a crucial role in understanding thorium solution chemistry, since their presence causes apparent solubility several orders of magnitude higher than predicted by thermodynamic data bases. Although electrospray mass spectrometry (ESI MS) identifies Th(IV) dimers and pentamers unequivocally as dominant species close to the solubility limit, the molecular structure of Th5(OH)y polymers was hitherto unknown. In the present study, X-ray absorption fine structure (XAFS) spectroscopy, high energy X-ray scattering (HEXS) measurements, and quantum chemical calculations are combined to solve the pentamer structure. The most favourable structure is represented by two Th(IV) dimers linked by a central Th(IV) cation through hydroxide bridges.

  3. Thorium-Free Versus Thoriated Plasma Gun Electrodes: Statistical Evaluation of Coating Properties

    NASA Astrophysics Data System (ADS)

    Colmenares-Angulo, Jose; Molz, Ronald; Hawley, David; Seshadri, Ramachandran Chidambaram

    2016-04-01

    Industries throughout the world today have an increased awareness of environmental, health, and safety issues. This, together with recent Nuclear Regulatory Commission changes concerning source material (e.g., thorium) has added complexity in the supply chain of thoriated tungsten commonly used in plasma spray gun spares. In the interest of a safer and more sustainable work environment, Oerlikon Metco has developed thorium-free material solutions proven to have longer service life than conventional thoriated spares. This work reports on the effect, if any, caused by tungsten compositional changes and extended service life in coating properties. Microstructure, coating efficiency parameters, hardness, particle state, in situ coating stress, and ex situ modulus are evaluated over the service life duration of the nozzle, comparing coatings with thoriated and non-thoriated nozzles and electrodes with the same spray parameters.

  4. Electrotransport and diffusivity of molybdenum, rhenium, tungsten, and zirconium in beta-thorium

    NASA Technical Reports Server (NTRS)

    Schmidt, F. A.; Beck, M. S.; Rehbein, D. K.; Conzemius, R. J.; Carlson, O. N.

    1984-01-01

    The electric mobilities, diffusivities, and effective valences were determined for molybdenum, rhenium, tungsten, and zirconium in beta-thorium. All four solutes migrated in the same direction as the electron flow. Rhenium and molybdenum were found to be very mobile, with tungsten somewhat slower. Zirconium was found to move at a rate near that of the self-diffusion of beta-thorium, viz., about 10 to the -11th sq m/s at 1500 C. The electromigration velocities showed a similar trend. A comparison was made between experimental data obtained by scanning laser mass spectrometry and theoretical transport equations for two purification experiments. Good agreement was obtained with both the concentration profile predicted by DeGroot and the purification ratio predicted by Verhoeven.

  5. A comparative study of thorium activity in NORM and high background radiation area.

    PubMed

    Sahoo, S K; Ishikawa, T; Tokonami, S; Sorimachi, A; Kranrod, C; Janik, M; Hosoda, M; Hassan, N M; Chanyotha, S; Parami, V K; Yonehara, H; Ramola, R C

    2010-10-01

    Several industrial processes are known to enrich naturally occurring radioactive materials (NORM). To assess such processes with respect to their radiological relevance, characteristic parameters describing this enrichment will lead to interesting information useful to UNSCEAR. In case of mineral treatment plants, the high temperatures used in smelting and refining processes lead to high concentrations of (238)U and (232)Th. Also due to thermal power combustion, concentration of U and Th in the fly ash increases manifold. NORM samples were collected from a Thailand mineral treatment plant and Philippine coal-fired thermal power plants for investigation. Some studies are initiated from a high background radiation area near Gopalpur of Orissa state in India. These NORM samples were analysed by gamma-ray spectrometry as well as inductively coupled plasma mass spectrometry. The radioactivity in case of Orissa soil samples is found to be mainly contributed from thorium. This study attempts to evaluate levels of thorium activity in NORM samples.

  6. Determination of thorium concentrations and activity ratios in silicate rocks by alpha spectrometry.

    PubMed

    dos Santos, R N; Marques, L S; Nicolai, S H A; Ribeiro, F B

    2004-01-01

    A detailed radiochemical procedure for alpha spectrometry measurements of thorium concentrations and of 230Th/232Th activity ratios in silicates is presented. The Th behaviour, during each step of the chemical process, was investigated by using a 234Th tracer, which is a gamma-ray emitter. The described chemical processing provides relatively high thorium yields, which varied between 56% and 88%, in the analysis of GB-1 (granite) and BB-1 (basalt) Brazilian geological standards. Also, the application of the established radiochemical method allowed a determination of both Th concentrations and activity ratios with high reproducibility, on the order of 2%. The estimation of the concentration result accuracy is also about 2%, which was calculated by using published data obtained from neutron activation analysis as reference values.

  7. Optimization of small long-life PWR based on thorium fuel

    SciTech Connect

    Subkhi, Moh Nurul; Suud, Zaki Waris, Abdul; Permana, Sidik

    2015-09-30

    A conceptual design of small long-life Pressurized Water Reactor (PWR) using thorium fuel has been investigated in neutronic aspect. The cell-burn up calculations were performed by PIJ SRAC code using nuclear data library based on JENDL 3.2, while the multi-energy-group diffusion calculations were optimized in three-dimension X-Y-Z geometry of core by COREBN. The excess reactivity of thorium nitride with ZIRLO cladding is considered during 5 years of burnup without refueling. Optimization of 350 MWe long life PWR based on 5% {sup 233}U & 2.8% {sup 231}Pa, 6% {sup 233}U & 2.8% {sup 231}Pa and 7% {sup 233}U & 6% {sup 231}Pa give low excess reactivity.

  8. Results of a direct search for the thorium-229 nuclear isomeric transition

    NASA Astrophysics Data System (ADS)

    Schneider, Christian; Jeet, Justin; Sullivan, Scott T.; Rellergert, Wade G.; Mirzadeh, Saed; Cassanho, A.; Jenssen, H. P.; Tkalya, Eugene V.; Hudson, Eric R.

    2015-05-01

    The nucleus of thorium-229 has an exceptionally low-energy isomeric transition in the vacuum-ultraviolet spectrum around 7 . 8 +/- 0 . 5 eV. The prospects of a laser-accessible nuclear transition are manifold but require spectroscopically resolving the transition. Our approach is a direct search using thorium-doped crystals as samples and exciting the isomeric state with vacuum-ultraviolet synchrotron radiation. In a recent experiment, we were able to search for the transition at the Advanced Light Source synchrotron, LBNL, between 7 . 3 eV and 8 . 8 eV. We found no evidence for the transition within a lifetime range of 1-2s to 2000-5600s. This result excludes large parts of the theoretically expected region. We conclude reporting on our efforts of a search using laser-generated vacuum-ultraviolet light.

  9. THE ATTRACTIVENESS OF MATERIAS ASSOCIATED WITH THORIUM-BASED NUCLEAR FUEL CYCLES FOR PHWRS

    SciTech Connect

    Prichard, Andrew W.; Niehus, Mark T.; Collins, Brian A.; Bathke, Charles G.; Ebbinghaus, Bartley B.; Hase, Kevin R.; Sleaford, Brad W.; Robel, Martin; Smith, Brian W.

    2011-07-17

    This paper reports the continued evaluation of the attractiveness of materials mixtures containing special nuclear materials (SNM) associated with thorium based nuclear fuel cycles. Specifically, this paper examines a thorium fuel cycle in which a pressurized heavy water reactor (PHWR) is fueled with mixtures of natural uranium/233U/thorium. This paper uses a PHWR fueled with natural uranium as a base fuel cycle, and then compares material attractiveness of fuel cycles that use 233U/thorium salted with natural uranium. The results include the material attractiveness of fuel at beginning of life (BoL), end of life (EoL), and the number of fuel assemblies required to collect a bare critical mass of plutonium or uranium. This study indicates what is required to render the uranium as having low utility for use in nuclear weapons; in addition, this study estimates the increased number of assemblies required to accumulate a bare critical mass of plutonium that has a higher utility for use in nuclear weapons. This approach identifies that some fuel cycles may be easier to implement the International Atomic Energy Agency (IAEA) safeguards approach and have a more effective safeguards by design outcome. For this study, approximately one year of fuel is required to be reprocessed to obtain one bare critical mass of plutonium. Nevertheless, the result of this paper suggests that all spent fuel needs to be rigorously safeguarded and provided with high levels of physical protection. This study was performed at the request of the United States Department of Energy /National Nuclear Security Administration (DOE/NNSA). The methodology and key findings will be presented.

  10. Ground state spontaneous fission half-lives from thorium to fermium

    SciTech Connect

    Holden, N.E.

    1988-01-01

    Measurements of the half-lives for spontaneous fission of the nuclidic ground states of elements from thorium to fermium have been compiled and evaluated. Recommended values are presented. An attempt has been made to distinguish between spontaneous fission and heavy ion emission. Spontaneously fissioning isomers have not been considered here. The difference between even-even nuclides and odd-even, even-odd and odd-odd nuclides are discussed. 3 tabs.

  11. Determination of thorium in seawater by neutron activation analysis and mass spectrometry

    SciTech Connect

    Huh, Chih-An

    1987-01-01

    The recent development of neutron activation analysis and mass spectrometric methods for the determination of /sup 232/Th in seawater has made possible rapid sampling and analysis of this long-lived, non-radiogenic thorium isotope on small-volume samples. The marine geochemical utility of /sup 232/Th, whose concentration in seawater is extremely low, warrants the development of these sensitive techniques. The analytical methods and some results are presented and discussed in this article. 24 refs., 3 figs.

  12. An improved radiochemical separation of uranium and thorium in environmental samples involving peroxide fusion.

    PubMed

    Galindo, C; Mougin, L; Nourreddine, A

    2007-01-01

    A radiochemical procedure for the accurate determination of uranium and thorium using peroxide fusion followed by ion exchange and extraction chromatography is described. The method of extraction of the element from solid samples is the most important factor in the investigation. It is demonstrated, by measuring a number of reference materials, that fusion with Na(2)O(2) ensures a complete destruction of the mineral lattice and greatly improves the determination of the true activity of actinides.

  13. A study of thorium exposure during tungsten inert gas welding in an airline engineering population.

    PubMed

    McElearney, N; Irvine, D

    1993-07-01

    To investigate the theoretic possibility of excessive exposure to thorium during the process of tungsten inert gas (TIG) welding using thoriated rods we carried out a cross-sectional study of TIG welders and an age- and skill-matched group. We measured the radiation doses from inhaled thorium that was retained in the body and investigated whether any differences in health or biologic indices could have been attributable to the welding and tip-grinding process. Sixty-four TIG welders, 11 non-TIG welders, and 61 control subjects from an airline engineering population participated. All of the subjects were interviewed for biographic, occupational history and morbidity details. All of the welders and eight control subjects carried out large-volume urine sampling to recover thorium 232 and thorium 228; this group also had chest radiographs. All of the subjects had a blood sample taken to estimate liver enzymes, and they provided small-volume urine samples for the estimation of retinol-binding protein and beta 2-microglobulin. We found no excess of morbidity among the TIG or non-TIG welding groups, and the levels of retinol-binding protein and beta 2-microglobulin were the same for both groups. There was a higher aspartate aminotransferase level in the control group. The internal radiation doses were estimated at less than an annual level of intake in all cases, and considerably less if the exposure (as was the case) was assumed to be chronic over many years. Some additional precautionary measures are suggested to reduce further any potential hazard from this process.

  14. Stabilization of Th{sup 3+} ions into mixed-valence thorium fluoride

    SciTech Connect

    Dubois, Marc; Dieudonne, Belto; Mesbah, Adel; Bonnet, Pierre; El-Ghozzi, Malika; Renaudin, Guillaume; Avignant, Daniel

    2011-01-15

    The unusual oxidation state +3 of the thorium has been stabilized into a lithium containing non-stoichiometric mixed-valence (III/IV) thorium fluorinated phase with formula Li{sub 2+x}Th{sub 12}F{sub 50} (0thorium fluoride. The electrochemical insertion of Li{sup +} ions into the open channels of the host matrix has been carried out at 60 {sup o}C, using an alkylcarbonate PC-LiClO{sub 4} 1 M electrolyte. The Li{sup +} and Th{sup 3+} contents, both in the starting composition and the Li{sup +} inserted ones, were investigated by high resolution solid state {sup 7}Li NMR and EPR, respectively. -- Graphical abstract: Electrochemical insertion of Li{sup +} ions into mixed-valence III/IV thorium fluoride and EPR spectra for the raw and inserted compounds. Display Omitted

  15. Thorium: Uranium fuel cycle in safe reactors, the time is now

    SciTech Connect

    Gat, Uri

    1995-12-31

    The thorium-uranium fuel cycle has several advantages that make it attractive. Some of these beneficial properties are of particular interest now as they help alleviate current concerns. The Th-U cycle has neutronic advantages when utilized in thermal or epithermal reactors. Some of these reactors enjoy extraordinary safety qualities. The combination of these traits suggest that now is an appropriate time to deploy and begin exploiting the Th-U fuel cycle.

  16. Solid phase extraction and preconcentration of uranium(VI) and thorium(IV) on Duolite XAD761 prior to their inductively coupled plasma mass spectrometric determination.

    PubMed

    Aydin, Funda Armagan; Soylak, Mustafa

    2007-04-15

    A simple and effective method is presented for the separation and preconcentration of thorium(IV) and uranium(VI) by solid phase extraction on Duolite XAD761 adsorption resin. Thorium(IV) and uranium(VI) 9-phenyl-3-fluorone chelates are formed and adsorbed onto the Duolite XAD761. Thorium(IV) and uranium(VI) are quantitatively eluted with 2molL(-1) HCl and determined by inductively coupled plasma-mass spectrometry (ICP-MS). The influences of analytical parameters including pH, amount of reagents, amount of Duolite XAD761 and sample volume, etc. were investigated on the recovery of analyte ions. The interference of a large number of anions and cations has been studied and the optimized conditions developed have been utilized for the trace determination of uranium and thorium. A preconcentration factor of 30 for uranium and thorium was achieved. The relative standard deviation (N=10) was 2.3% for uranium and 4.5% for thorium ions for 10 replicate determinations in the solution containing 0.5mug of uranium and thorium. The three sigma detection limits (N=15) for thorium(IV) and uranium(VI) ions were found to be 4.5 and 6.3ngL(-1), respectively. The developed solid phase extraction method was successively utilized for the determination of traces thorium(IV) and uranium(VI) in environmental samples by ICP-MS.

  17. Further evaluations of the toxicity of irradiated advanced heavy water reactor fuels.

    PubMed

    Edwards, Geoffrey W R; Priest, Nicholas D

    2014-11-01

    The neutron economy and online refueling capability of heavy water moderated reactors enable them to use many different fuel types, such as low enriched uranium, plutonium mixed with uranium, or plutonium and/or U mixed with thorium, in addition to their traditional natural uranium fuel. However, the toxicity and radiological protection methods for fuels other than natural uranium are not well established. A previous paper by the current authors compared the composition and toxicity of irradiated natural uranium to that of three potential advanced heavy water fuels not containing plutonium, and this work uses the same method to compare irradiated natural uranium to three other fuels that do contain plutonium in their initial composition. All three of the new fuels are assumed to incorporate plutonium isotopes characteristic of those that would be recovered from light water reactor fuel via reprocessing. The first fuel investigated is a homogeneous thorium-plutonium fuel designed for a once-through fuel cycle without reprocessing. The second fuel is a heterogeneous thorium-plutonium-U bundle, with graded enrichments of U in different parts of a single fuel assembly. This fuel is assumed to be part of a recycling scenario in which U from previously irradiated fuel is recovered. The third fuel is one in which plutonium and Am are mixed with natural uranium. Each of these fuels, because of the presence of plutonium in the initial composition, is determined to be considerably more radiotoxic than is standard natural uranium. Canadian nuclear safety regulations require that techniques be available for the measurement of 1 mSv of committed effective dose after exposure to irradiated fuel. For natural uranium fuel, the isotope Pu is a significant contributor to the committed effective dose after exposure, and thermal ionization mass spectrometry is sensitive enough that the amount of Pu excreted in urine is sufficient to estimate internal doses, from all isotopes, as low

  18. Triamidoamine thorium-arsenic complexes with parent arsenide, arsinidiide and arsenido structural motifs

    PubMed Central

    Wildman, Elizabeth P.; Balázs, Gábor; Wooles, Ashley J.; Scheer, Manfred; Liddle, Stephen T.

    2017-01-01

    Despite a major expansion of uranium–ligand multiple bond chemistry in recent years, analogous complexes involving other actinides (An) remain scarce. For thorium, under ambient conditions only a few multiple bonds to carbon, nitrogen, phosphorus and chalcogenides are reported, and none to arsenic are known; indeed only two complexes with thorium–arsenic single bonds have been structurally authenticated, reflecting the challenges of stabilizing polar linkages at the large thorium ion. Here, we report thorium parent–arsenide (ThAsH2), –arsinidiides (ThAs(H)K and ThAs(H)Th) and arsenido (ThAsTh) linkages stabilized by a bulky triamidoamine ligand. The ThAs(H)K and ThAsTh linkages exhibit polarized-covalent thorium–arsenic multiple bonding interactions, hitherto restricted to cryogenic matrix isolation experiments, and the AnAs(H)An and AnAsAn linkages reported here have no precedent in f-block chemistry. 7s, 6d and 5f orbital contributions to the Th–As bonds are suggested by quantum chemical calculations, and their compositions unexpectedly appear to be tensioned differently compared to phosphorus congeners. PMID:28276437

  19. Thorium-Fueled Underground Power Plant Based on Molten Salt Technology

    SciTech Connect

    Moir, Ralph W.; Teller, Edward

    2005-09-15

    This paper addresses the problems posed by running out of oil and gas supplies and the environmental problems that are due to greenhouse gases by suggesting the use of the energy available in the resource thorium, which is much more plentiful than the conventional nuclear fuel uranium. We propose the burning of this thorium dissolved as a fluoride in molten salt in the minimum viscosity mixture of LiF and BeF{sub 2} together with a small amount of {sup 235}U or plutonium fluoride to initiate the process to be located at least 10 m underground. The fission products could be stored at the same underground location. With graphite replacement or new cores and with the liquid fuel transferred to the new cores periodically, the power plant could operate for up to 200 yr with no transport of fissile material to the reactor or of wastes from the reactor during this period. Advantages that include utilization of an abundant fuel, inaccessibility of that fuel to terrorists or for diversion to weapons use, together with good economics and safety features such as an underground location will diminish public concerns. We call for the construction of a small prototype thorium-burning reactor.

  20. Separation of thorium (IV) from lanthanide concentrate (LC) and water leach purification (WLP) residue

    SciTech Connect

    AL-Areqi, Wadeeah M.; Majid, Amran Ab.; Sarmani, Sukiman

    2014-09-03

    Thorium (IV) content in industrial residue produced from rare earth elements production industry is one of the challenges to Malaysian environment. Separation of thorium from the lanthanide concentrate (LC) and Water Leach Purification (WLP) residue from rare earth elements production plant is described. Both materials have been tested by sulphuric acid and alkaline digestions. Th concentrations in LC and WLP were determined to be 1289.7 ± 129 and 1952.9±17.6 ppm respectively. The results of separation show that the recovery of Th separation from rare earth in LC after concentrated sulphuric acid dissolution and reduction of acidity to precipitate Th was found 1.76-1.20% whereas Th recovery from WLP was less than 4% after concentrated acids and alkali digestion processes. Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) was used to determine Th concentrations in aqueous phase during separation stages. This study indicated that thorium maybe exists in refractory and insoluble form which is difficult to separate by these processes and stays in WLP residue as naturally occurring radioactive material (NORM)

  1. Performance of the fissionTPC and the Potential to Advance the Thorium Fuel Cycle

    NASA Astrophysics Data System (ADS)

    Towell, Rusty; Niffte Collaboration

    2014-09-01

    The NIFFTE fission Time Projection Chamber (fissionTPC) is a powerful tool that is being developed to take precision measurements of neutron-induced fission cross sections of transuranic elements. During the last run at the Los Alamos Neutron Science Center (LANSCE) the fully instrumented TPC took data for the first time. The exquisite tracking capabilities of this device allow the full reconstruction of charged particles produced by neutron beam induced fissions from a thin central target. The wealth of information gained from this approach will allow cross section systematics to be controlled at the level of 1%. The fissionTPC performance from this run will be shared. These results are critical to the development of advanced uranium-fueled reactors. However, there are clear advantages to developing thorium-fueled reactors including the abundance of thorium verses uranium, minimizing radioactive waste, improved reactor safety, and enhanced proliferation resistance. The potential for using the fissionTPC to measure needed cross sections important to the development of thorium fueled nuclear reactors will also be discussed.

  2. Sustainable Thorium Nuclear Fuel Cycles: A Comparison of Intermediate and Fast Neutron Spectrum Systems

    SciTech Connect

    Brown, Nicholas R.; Powers, Jeffrey J.; Feng, B.; Heidet, F.; Stauff, N.; Zhang, G.; Todosow, Michael; Worrall, Andrew; Gehin, Jess C.; Kim, T. K.; Taiwo, T. A.

    2015-05-21

    This paper presents analyses of possible reactor representations of a nuclear fuel cycle with continuous recycling of thorium and produced uranium (mostly U-233) with thorium-only feed. The analysis was performed in the context of a U.S. Department of Energy effort to develop a compendium of informative nuclear fuel cycle performance data. The objective of this paper is to determine whether intermediate spectrum systems, having a majority of fission events occurring with incident neutron energies between 1 eV and 105 eV, perform as well as fast spectrum systems in this fuel cycle. The intermediate spectrum options analyzed include tight lattice heavy or light water-cooled reactors, continuously refueled molten salt reactors, and a sodium-cooled reactor with hydride fuel. All options were modeled in reactor physics codes to calculate their lattice physics, spectrum characteristics, and fuel compositions over time. Based on these results, detailed metrics were calculated to compare the fuel cycle performance. These metrics include waste management and resource utilization, and are binned to accommodate uncertainties. The performance of the intermediate systems for this selfsustaining thorium fuel cycle was similar to a representative fast spectrum system. However, the number of fission neutrons emitted per neutron absorbed limits performance in intermediate spectrum systems.

  3. Crystalline thorium selenite monohydrate: Synthesis and thermodynamic research of dehydration process

    NASA Astrophysics Data System (ADS)

    Nesterenko, V. P.; Glybin, V. P.

    1999-01-01

    The crystal monohydrate of thorium selenite Th(SeO3)2 H2O was obtained by the Th(IV) precipitation selenious acid from water solution. The yield of the mentioned compound in regard to Th (IV) was up to 100%. The identity of the compound was proved by the methods of X-Ray phase analysis and derivatography. The process of synthesized thorium selenite monohydrate dehydration was studied by the vapour pressure method. The values of enthalpy and entropy of the dehydration process are Δ H {/T /0}=92.9±2.1 kJ.mol-1 and Δ S {/T /0}=187.9±3.8 J.mol-1, respectively. On the basis of the value of dehydration enthalpy and calculated standard enthalpy of anhydrous thorium selenite formation Δ f H 0 (Th(SeO3)2 (cr); 298 K), the value Δ f H 0 (Th(SeO3)2H2O (cr); 298 K) was obtained which was found to be -2082.4±8 kJ.mol-1.

  4. Crystalline thorium selenite monohydrate: Synthesis and thermodynamic research of dehydration process

    NASA Astrophysics Data System (ADS)

    Nesterenko, V. P.; Glybin, V. P.

    1999-01-01

    The crystal monohydrate of thorium selenite Th(SeO3)2 H2O was obtained by the Th(IV) precipitation selenious acid from water solution. The yield of the mentioned compound in regard to Th (IV) was up to 100%. The identity of the compound was proved by the methods of X-Ray phase analysis and derivatography. The process of synthesized thorium selenite monohydrate dehydration was studied by the vapour pressure method. The values of enthalpy and entropy of the dehydration process are ΔH T /0 =92.9±2.1 kJ.mol-1 and ΔS T /0 =187.9±3.8 J.mol-1, respectively. On the basis of the value of dehydration enthalpy and calculated standard enthalpy of anhydrous thorium selenite formation Δ f H 0 (Th(SeO3)2 (cr); 298 K), the value Δ f H 0 (Th(SeO3)2H2O (cr); 298 K) was obtained which was found to be -2082.4±8 kJ.mol-1.

  5. Sustainable Thorium Nuclear Fuel Cycles: A Comparison of Intermediate and Fast Neutron Spectrum Systems

    DOE PAGES

    Brown, Nicholas R.; Powers, Jeffrey J.; Feng, B.; ...

    2015-05-21

    This paper presents analyses of possible reactor representations of a nuclear fuel cycle with continuous recycling of thorium and produced uranium (mostly U-233) with thorium-only feed. The analysis was performed in the context of a U.S. Department of Energy effort to develop a compendium of informative nuclear fuel cycle performance data. The objective of this paper is to determine whether intermediate spectrum systems, having a majority of fission events occurring with incident neutron energies between 1 eV and 105 eV, perform as well as fast spectrum systems in this fuel cycle. The intermediate spectrum options analyzed include tight lattice heavymore » or light water-cooled reactors, continuously refueled molten salt reactors, and a sodium-cooled reactor with hydride fuel. All options were modeled in reactor physics codes to calculate their lattice physics, spectrum characteristics, and fuel compositions over time. Based on these results, detailed metrics were calculated to compare the fuel cycle performance. These metrics include waste management and resource utilization, and are binned to accommodate uncertainties. The performance of the intermediate systems for this selfsustaining thorium fuel cycle was similar to a representative fast spectrum system. However, the number of fission neutrons emitted per neutron absorbed limits performance in intermediate spectrum systems.« less

  6. Substitution reactions of thorium(IV) acetate to synthesize nano-sized carboxylate complexes

    NASA Astrophysics Data System (ADS)

    Baranwal, Balram P.; Fatma, Talat; Varma, Anand; Singh, Alok K.

    2010-04-01

    Some mixed-ligand thorium(IV) complexes with the general formula [Th(OOCCH 3) 4- nL n] (L = anions of myristic, palmitic or stearic acid and n = 1-4) have been synthesized by the stepwise substitution of acetate ions of thorium(IV) acetate with straight chain carboxylic acids in toluene under reflux. The complexes were characterized by elemental analyses, spectral (electronic, infrared, NMR and powder XRD) studies, electrical conductance and magnetic susceptibility measurements. Doubly and triply bridged coordination modes of the ligands were established by their infrared spectra and nano-size of the complexes by powder XRD. Room temperature magnetic susceptibility measurements revealed diamagnetic nature of the complexes. Electronic absorption spectra of the complexes showed π → π*, n → π* and charge transfer transitions. Molar conductance values indicated the complex to be non-electrolytes. These are a new type of mixed-ligand thorium(IV) complexes for which a nano-sized, oxygen bridged polymeric structure has been established on the basis of physico-chemical studies.

  7. Separation of thorium (IV) from lanthanide concentrate (LC) and water leach purification (WLP) residue

    NASA Astrophysics Data System (ADS)

    AL-Areqi, Wadeeah M.; Majid, Amran Ab.; Sarmani, Sukiman

    2014-09-01

    Thorium (IV) content in industrial residue produced from rare earth elements production industry is one of the challenges to Malaysian environment. Separation of thorium from the lanthanide concentrate (LC) and Water Leach Purification (WLP) residue from rare earth elements production plant is described. Both materials have been tested by sulphuric acid and alkaline digestions. Th concentrations in LC and WLP were determined to be 1289.7 ± 129 and 1952.9±17.6 ppm respectively. The results of separation show that the recovery of Th separation from rare earth in LC after concentrated sulphuric acid dissolution and reduction of acidity to precipitate Th was found 1.76-1.20% whereas Th recovery from WLP was less than 4% after concentrated acids and alkali digestion processes. Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) was used to determine Th concentrations in aqueous phase during separation stages. This study indicated that thorium maybe exists in refractory and insoluble form which is difficult to separate by these processes and stays in WLP residue as naturally occurring radioactive material (NORM).

  8. Effect of thorium on the growth and capsule morphology of Bradyrhizobium.

    PubMed

    Santamaría, Mónica; Díaz-Marrero, Ana R; Hernández, Jairo; Gutiérrez-Navarro, Angel M; Corzo, Javier

    2003-10-01

    The thorium effect on Bradyrhizobium growth was assayed in liquid media. Th4+ inhibited the growth of Bradyrhizobium (Chamaecytisus) BGA-1, but this effect decreased in the presence of suspensions of live or dead bacterial cells. Th4+ induced the formation of a gel-like precipitate when added to a dense suspension of B. (Chamaecytisus) BGA-1 cells. Viable Bradyrhizobium cells remained in suspension after precipitate formation. Thorium was recovered in the precipitate, in which polysaccharide, lipopolysaccharide and proteins were also found. After Th4+ addition, the morphology of B. (Chamaecytisus) BGA-1 or Bradyrhizobium japonicum USDA 110 sedimented cells studied by scanning electron microscopy changed from an entangled network of capsulated bacteria to uncapsulated individual cells and an amorphous precipitate. Energy-dispersive X-ray spectroscopy showed that thorium was mainly in the amorphous fraction. Precipitate was also formed between B. (Chamaecytisus) BGA-1 and Al3+, which was also toxic to this bacterium. Precipitate induced by Th4+ or Al3+ was found in all Bradyrhizobium and Sinorhizobium strains tested, but not in Rhizobium, Salmonella typhimurium, Aerobacter aerogenes or Escherichia coli. These results suggest a specific defence mechanism based on metal precipitation by extracellular polymers.

  9. A Tetrapositive Metal Ion in the Gas Phase: Thorium(IV) Coordinated by Neutral Tridentate Ligands

    SciTech Connect

    Gong, Yu; Hu, Han-Shi; Tian, Guoxin; Rao, Linfeng; Li, Jun; Gibson, John K.

    2013-07-01

    ESI of 1:1 mixtures of Th(ClO₄)₄ and ligand TMOGA in acetonitrile resulted in the observation of the TMOGA supported tetracation, Th(L)₃⁴⁺, in the gas phase. Three TMOGA ligands are necessary to stabilize the tetrapositive thorium ion; no Th(L)₂⁴⁺ or Th(L)₄⁴⁺ was observed. Theoretical calculations reveal that the Th(L)₃⁴⁺ complex possesses C₃ symmetry with the thorium center coordinated by nine oxygen atoms from three ligands, which forms a twisted TPP geometry. Actinide compounds with such a geometry feature a nine-coordinate chiral actinide center. The Th-L binding energy and bond orders of Th(L)n⁴⁺ decrease as the coordination number increases, consistent with the trend of concurrently increasing Th-O distances. The Th-O bonding is mainly electrostatic in nature, but the covalent interactions are not negligible. CID of the Th(L)₃⁴⁺ complex mainly resulted in charge reduction to form Th(L)₂(L-86)³⁺oss of neutral TMOGA was not observed. The protic ligand methanol stabilized only tri- and dications of ligated thorium. The intensity of the Th(L)₃⁴⁺ peak was reduced as the percentage of water increased in the Th(ClO₄)₄/TMOGA solution.

  10. Weapons-Grade Plutonium-Thorium PWR Assembly Design and Core Safety Analysis

    SciTech Connect

    Dziadosz, David; Ake, Timothy N.; Saglam, Mehmet; Sapyta, Joe J.

    2004-07-15

    A light water reactor (LWR) fuel assembly design consisting of a blend of weapons-grade plutonium and natural thorium oxides was examined. The design meets current thermal-hydraulic and safety criteria. Such an assembly would have enough reactivity to achieve three cycles of operation. The pin power distribution indicates a fairly level distribution across the assembly, avoiding hot spots near guide tubes, corners, and other sections where excessive power would create significant loss to thermal-hydraulic margins.This work examined a number of physics and core safety analysis parameters that impact the operation and safety of power reactors. Such parameters as moderator coefficients of reactivity, Doppler coefficients, soluble boron worth, control rod worth, prompt neutron lifetime, and delayed-neutron fractions were considered. These in turn were used to examine reactor behavior during a number of operational conditions, transients, and accidents. Such conditions as shutdown from power with one rod stuck out, steam-line break accident, feedwater line break, loss of coolant flow, locked rotor accidents, control rod ejection accidents, and anticipated transients without scram (ATWSs) were examined.The analysis of selected reactor transients demonstrated that it is feasible to license and safely operate a reactor fueled with plutonium-thorium blended fuel. In most cases analyzed, the thorium mixture had less-severe consequences than those for a core comprising low-enriched uranium fuel. In the analyzed cases where the consequences were more severe, they were still within acceptable limits. The ATWS accident condition requires more analysis.

  11. Thorium aspartate tetrahydrate precursor to ThO2: Comparison of hydrothermal and thermal conversions

    NASA Astrophysics Data System (ADS)

    Clavier, N.; Maynadié, J.; Mesbah, A.; Hidalgo, J.; Lauwerier, R.; Nkou Bouala, G. I.; Parrès-Maynadié, S.; Meyer, D.; Dacheux, N.; Podor, R.

    2017-04-01

    The synthesis of original crystalline thorium aspartate tetrahydrate, Th(C4NO4H6)4.4H2O, was performed using two different wet-chemistry routes, involving either L-asparagine or L-aspartic acid as complexing agent. Characterization of this compound through 13C NMR and PXRD led to confirm the terminal coordination mode of the aspartate group and to suggest a potential cubic lattice (Pn-3 space group). Vibrational spectroscopy data were also collected. The conversion of thorium aspartate tetrahydrate into thorium dioxide was further performed through classical high temperature heat treatment or under hydrothermal conditions. On the one hand, thermal treatment provided a pseudomorphic conversion which retained the starting morphology, and favored the increase of the average crystallite size, as well as the complete elimination of the residual carbon content. On the other, hydrothermal conversion could be used to tune the morphology of the final oxide, ThO2.nH2O microspheres being prepared when starting from L-asparagine.

  12. Alkalic rocks and resources of thorium and associated elements in the Powderhorn District, Gunnison County, Colorado

    USGS Publications Warehouse

    Olson, J.C.; Hedlund, D.C.

    1981-01-01

    Alkalic igneous rocks and related concentrations of thorium, niobium, rare-earth elements, titanium, and other elements have long been known in the Powderhorn mining district and have been explored intermittently for several decades. The deposits formed chiefly about 570 m.y. (million years) ago in latest Precambrian or Early Cambrian time. They were emplaced in lower Proterozoic (Proterozoic X) metasedimentary, metavolcanic, and plutonic rocks. The complex of alkalic rocks of Iron Hill occupies 31 km 2 (square kilometers) and is composed of pyroxenite, uncompahgrite, ijolite, nepheline syenite, and carbonatite, in order of generally decreasing age. Fenite occurs in a zone, in places more than 0.6 km (kilometer) wide, around a large part of the margin of the complex and adjacent to alkalic dikes intruding Precambrian host rock. The alkalic rocks have a radioactivity, chiefly due to thorium, greater than that of the surrounding Powderhorn Granite (Proterozoic X) and metamorphic rocks. The pyroxenite, uncompahgrite, ijolite, and nepheline syenite, which form more than 80 percent of the complex, have fairly uniform radioactivity. Radioactivity in the carbonatite stock, carbonatite dikes, and the carbonatite-pyroxenite mixed rock zone, however, generally exceeds that in the other rocks of the complex. The thorium concentrations in the Powderhorn district occur in six types of deposits: thorite veins, a large massive carbonatite body, carbonatite dikes, trachyte dikes, magnetite-ilmeniteperovskite dikes or segregations, and disseminations in small, anomalously radioactive plutons chiefly of granite or quartz syenite that are older than rocks of the alkalic complex. The highest grade thorium concentrations in the district are in veins that commonly occur in steeply dipping, crosscutting shear or breccia zones in the Precambrian rocks. They range in thickness from a centimeter or less to 5 m (meters) and are as much as 1 km long. The thorite veins are composed chiefly of

  13. Uranium, thorium and rare earth elements in macrofungi: what are the genuine concentrations?

    PubMed

    Borovička, Jan; Kubrová, Jaroslava; Rohovec, Jan; Randa, Zdeněk; Dunn, Colin E

    2011-10-01

    Concentrations of uranium, thorium and rare earth elements (REE) in 36 species of ectomycorrhizal (26 samples) and saprobic (25 samples) macrofungi from unpolluted sites with differing bedrock geochemistry were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). Analytical results are supported by use of certified reference materials (BCR-670, BCR-667, NIST-1575a) and the reliability of the determination of uranium was verified by epithermal neutron activation analysis (ENAA). It appears that data recently published on these elements are erroneous, in part because of use of an inappropriate analytical method; and in part because of apparent contamination by soil particles resulting in elevated levels of thorium and REE. Macrofungi from unpolluted areas, in general, did not accumulate high levels of the investigated metals. Concentrations of uranium and thorium were generally below 30 and 125 μg kg(-1) (dry weight), respectively. Concentrations of REE in macrofungi did not exceed 360 μg kg(-1) (dry weight) and their distribution more or less followed the trend observed in post-Archean shales and loess.

  14. Substitution reactions of thorium(IV) acetate to synthesize nano-sized carboxylate complexes.

    PubMed

    Baranwal, Balram P; Fatma, Talat; Varma, Anand; Singh, Alok K

    2010-04-01

    Some mixed-ligand thorium(IV) complexes with the general formula [Th(OOCCH(3))(4-n)L(n)] (L=anions of myristic, palmitic or stearic acid and n=1-4) have been synthesized by the stepwise substitution of acetate ions of thorium(IV) acetate with straight chain carboxylic acids in toluene under reflux. The complexes were characterized by elemental analyses, spectral (electronic, infrared, NMR and powder XRD) studies, electrical conductance and magnetic susceptibility measurements. Doubly and triply bridged coordination modes of the ligands were established by their infrared spectra and nano-size of the complexes by powder XRD. Room temperature magnetic susceptibility measurements revealed diamagnetic nature of the complexes. Electronic absorption spectra of the complexes showed pi-->pi*, n-->pi* and charge transfer transitions. Molar conductance values indicated the complex to be non-electrolytes. These are a new type of mixed-ligand thorium(IV) complexes for which a nano-sized, oxygen bridged polymeric structure has been established on the basis of physico-chemical studies.

  15. COMBINED ANALYSIS OF THORIUM AND FAST NEUTRON DATA AT THE LUNAR SURFACE

    SciTech Connect

    O. GASNAULT; W. FELDMAN; ET AL

    2001-01-01

    The global distribution of the radioactive elements (U, K, Th) at the lunar surface is an important parameter for an understanding of lunar evolution, because they have provided continuous heat over the lifetime of the Moon. Today, only the thorium distribution is available for the whole lunar surface [1]. Another key parameter that characterize the surface of the Moon is the presence of mare basalts. These basalts are concentrated on the nearside and are represented by materials with high-Fe content, sometimes associated with high-Ti. We demonstrated elsewhere that the fast neutron measurement made by Lunar Prospector is representative of the average soil atomic mass [2]. is primarily dominated by Fe and Ti in basaltic terranes, and therefore the map of the fast neutrons provides a good delineation of mare basalts. We focus here on the correlated variations of thorium abundances and fast neutron fluxes averaged over areas of 360 km in diameter, in an attempt to provide a better understanding of the thorium emplacement on the surface of the Moon.

  16. Poisson regression analysis of mortality among male workers at a thorium-processing plant

    SciTech Connect

    Liu, Zhiyuan; Lee, Tze-San; Kotek, T.J.

    1991-12-31

    Analyses of mortality among a cohort of 3119 male workers employed between 1915 and 1973 at a thorium-processing plant were updated to the end of 1982. Of the whole group, 761 men were deceased and 2161 men were still alive, while 197 men were lost to follow-up. A total of 250 deaths was added to the 511 deaths observed in the previous study. The standardized mortality ratio (SMR) for all causes of death was 1.12 with 95% confidence interval (CI) of 1.05-1.21. The SMRs were also significantly increased for all malignant neoplasms (SMR = 1.23, 95% CI = 1.04-1.43) and lung cancer (SMR = 1.36, 95% CI = 1.02-1.78). Poisson regression analysis was employed to evaluate the joint effects of job classification, duration of employment, time since first employment, age and year at first employment on mortality of all malignant neoplasms and lung cancer. A comparison of internal and external analyses with the Poisson regression model was also conducted and showed no obvious difference in fitting the data on lung cancer mortality of the thorium workers. The results of the multivariate analysis showed that there was no significant effect of all the study factors on mortality due to all malignant neoplasms and lung cancer. Therefore, further study is needed for the former thorium workers.

  17. A Review of Thorium Utilization as an option for Advanced Fuel Cycle--Potential Option for Brazil in the Future

    SciTech Connect

    Maiorino, J.R.; Carluccio, T.

    2004-10-03

    Since the beginning of Nuclear Energy Development, Thorium was considered as a potential fuel, mainly due to the potential to produce fissile uranium 233. Several Th/U fuel cycles, using thermal and fast reactors were proposed, such as the Radkwoski once through fuel cycle for PWR and VVER, the thorium fuel cycles for CANDU Reactors, the utilization in Molten Salt Reactors, the utilization of thorium in thermal (AHWR), and fast reactors (FBTR) in India, and more recently in innovative reactors, mainly Accelerator Driven System, in a double strata fuel cycle. All these concepts besides the increase in natural nuclear resources are justified by non proliferation issues (plutonium constrain) and the waste radiological toxicity reduction. The paper intended to summarize these developments, with an emphasis in the Th/U double strata fuel cycle using ADS. Brazil has one of the biggest natural reserves of thorium, estimated in 1.2 millions of tons of ThO{sub 2}, as will be reviewed in this paper, and therefore R&D programs would be of strategically national interest. In fact, in the past there was some projects to utilize Thorium in Reactors, as the ''Instinto/Toruna'' Project, in cooperation with France, to utilize Thorium in Pressurized Heavy Water Reactor, in the mid of sixties to mid of seventies, and the thorium utilization in PWR, in cooperation with German, from 1979-1988. The paper will review these initiatives in Brazil, and will propose to continue in Brazil activities related with Th/U fuel cycle.

  18. Métastases gastro-intestinales du cancer du sein: à propos de 2 cas

    PubMed Central

    Loubna, Mezouar; Mohamed, El Hfid; Tijani, El Harroudi; Fouzia, Ghadouani; Hanane, Haj Kacem; Zouhour, Bourhaleb; Asmae, Ouabdelmoumen

    2013-01-01

    Le cancer du sein est le cancer le plus fréquent chez la femme, notamment au Maroc, avec un taux de mortalité élevé. Les métastases gastro-intestinales d'un carcinome canalaire du sein sont rares. Leur diagnostic est difficile du fait de la nature non spécifique des symptômes. Nous rapportons deux observations originales de métastases gastroduodénales d'un cancer canalaire infiltrant du sein. Les métastases gastro-intestinales du cancer du sein sont très rares; la présence de symptômes gastro-intestinaux chez une malade ayant un antécédent de cancer du sein doit faire suspecter une atteinte métastatique gastro-intestinale. PMID:24198876

  19. Use of Irradiated Foods

    NASA Technical Reports Server (NTRS)

    Brynjolfsson, A.

    1985-01-01

    The safety of irradiated foods is reviewed. Guidelines and regulations for processing irradiated foods are considered. The radiolytic products formed in food when it is irradiated and its wholesomeness is discussed. It is concluded that food irradiation processing is not a panacea for all problems in food processing but when properly used will serve the space station well.

  20. Use of Irradiated Foods

    NASA Technical Reports Server (NTRS)

    Brynjolfsson, A.

    1985-01-01

    The safety of irradiated foods is reviewed. Guidelines and regulations for processing irradiated foods are considered. The radiolytic products formed in food when it is irradiated and its wholesomeness is discussed. It is concluded that food irradiation processing is not a panacea for all problems in food processing but when properly used will serve the space station well.

  1. Detection of irradiated liquor

    NASA Astrophysics Data System (ADS)

    Shengchu, Qi; Jilan, Wu; Rongyao, Yuan

    D-2,3-butanediol is formed by irradiation processes in irradiated liquors. This radiolytic product is not formed in unirradiated liquors and its presence can therefore be used to identify whether a liquor has been irradiated or not. The relation meso/dl≈1 for 2,3-butanediol and the amount present in irradiated liquors may therefore be used as an indication of the dose used in the irradiation.

  2. Thorium-uranium fractionation by garnet - Evidence for a deep source and rapid rise of oceanic basalts

    NASA Technical Reports Server (NTRS)

    Latourrette, T. Z.; Kennedy, A. K.; Wasserburg, G. J.

    1993-01-01

    Mid-ocean ridge basalts (MORBs) and ocean island basalts (OIBs) are derived by partial melting of the upper mantle and are marked by systematic excesses of thorium-230 activity relative to the activity of its parent, uranium-238. Experimental measurements of the distribution of thorium and uranium between the melt and solid residue show that, of the major phases in the upper mantle, only garnet will retain uranium over thorium. This sense of fractionation, which is opposite to that caused by clinopyroxene-melt partitioning, is consistent with the thorium-230 excesses observed in young oceanic basalts. Thus, both MORBs and OIBs must begin partial melting in the garnet stability field or below about 70 kilometers. A calculation shows that the thorium-230-uranium-238 disequilibrium in MORBs can be attributed to dynamic partial melting beginning at 80 kilometers with a melt porosity of 0.2 percent or more. This result requires that melting beneath ridges occurs in a wide region and that the magma rises to the surface at a velocity of at least 0.9 meter per year.

  3. Thorium-uranium fractionation by garnet - Evidence for a deep source and rapid rise of oceanic basalts

    NASA Technical Reports Server (NTRS)

    Latourrette, T. Z.; Kennedy, A. K.; Wasserburg, G. J.

    1993-01-01

    Mid-ocean ridge basalts (MORBs) and ocean island basalts (OIBs) are derived by partial melting of the upper mantle and are marked by systematic excesses of thorium-230 activity relative to the activity of its parent, uranium-238. Experimental measurements of the distribution of thorium and uranium between the melt and solid residue show that, of the major phases in the upper mantle, only garnet will retain uranium over thorium. This sense of fractionation, which is opposite to that caused by clinopyroxene-melt partitioning, is consistent with the thorium-230 excesses observed in young oceanic basalts. Thus, both MORBs and OIBs must begin partial melting in the garnet stability field or below about 70 kilometers. A calculation shows that the thorium-230-uranium-238 disequilibrium in MORBs can be attributed to dynamic partial melting beginning at 80 kilometers with a melt porosity of 0.2 percent or more. This result requires that melting beneath ridges occurs in a wide region and that the magma rises to the surface at a velocity of at least 0.9 meter per year.

  4. 10 CFR 40.28 - General license for custody and long-term care of uranium or thorium byproduct materials disposal...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... in this part for uranium or thorium mill tailings sites closed under title II of the Uranium Mill Tailings Radiation Control Act of 1978, as amended. The licensee will be the Department of Energy, another... this general license is to ensure that uranium and thorium mill tailings disposal sites will be cared...

  5. 10 CFR 40.28 - General license for custody and long-term care of uranium or thorium byproduct materials disposal...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... in this part for uranium or thorium mill tailings sites closed under title II of the Uranium Mill... this general license is to ensure that uranium and thorium mill tailings disposal sites will be cared... may issue a specific license, as specified in the Uranium Mill Tailings Radiation Control Act of...

  6. Formation of solid thorium monoxide at near-ambient conditions as observed by neutron reflectometry and interpreted by screened hybrid functional calculations

    NASA Astrophysics Data System (ADS)

    He, Heming; Majewski, Jaroslaw; Allred, David D.; Wang, Peng; Wen, Xiaodong; Rector, Kirk D.

    2017-04-01

    Oxidation of a ∼1000 Å sputter-deposited thorium thin film at 150 °C in 100 ppm of flowing oxygen in argon produces the long-sought solid form of thorium monoxide. Changes in the scattering length density (SLD) distribution in the film over the 700-min experiment measured by in-situ, dynamic neutron reflectometry (NR) shows the densities, compositions and thickness of the various thorium oxides layers formed. Screened, hybrid density-functional theory calculations of potential thorium oxides aid interpretation, providing atomic-level picture and energetics for understanding oxygen migration. NR provided evidence of the formation of substoichiometric thorium oxide, ThOy (y < 1) at the interface between the unreacted thorium metal and its dioxide overcoat which grows inward, consuming the thorium at a rate of 2.1 Å/min while y increases until reaching 1:1 oxygen-to-thorium. Its presence indicates that kinetically-favored solid-phase ThO can be preferentially generated as a majority phase under the thermodynamically-favored ThO2 top layer at conditions close to ambient.

  7. Émission X(L) du xénon par interaction laser-agrégats

    NASA Astrophysics Data System (ADS)

    Adoui, L.; Gobert, O.; Indelicato, P.; Lamour, E.; Meynadier, P.; Normand, D.; Perdrix, M.; Prigent, C.; Rozet, J.-P.; Vernhet, D.

    2003-06-01

    Nous avons étudié le rayonnement X provenant d'ions fortement multichargés (ge24+) présentant des lacunes en couche L produits lors de l'irradiation d'agrégats de xénon par des impulsions lumineuses issues d'un laser femtoseconde de puissance. Les résultats obtenus lors de la toute dernière campagne d'expériences réalisée auprès du serveur LUCA du SPAM/DRECAM au CEA/Saclay mettent en cause certains travaux antérieurs [4-6]. Des divergences marquées apparaissent tant au niveau de l'interprétation des spectres X que sur la variation du taux d'émission en fonction de l'éclairement et de la longueur d'onde.

  8. Thorium and uranium porphyrins. Synthesis and crystal structure of bis(acetylacetonato)(2,3,7,8,12,13,17,18-octaethylporphyrinato)thorium(IV)

    SciTech Connect

    Dormond, A.; Belkalem, B.; Charpin, P.; Lance, M.; Vigner, D.; Folcher, G.; Guilard, R.

    1986-12-17

    The action of thorium tetrachloride or uranium tetrachloride with porphyrins affords the dichloro complexes (Por)MCl/sub 2/ (M = Th or U). The latter derivatives react with sodium acetylacetonate giving rise to bis(acetylacetonato) complexes (Por)M(acac)/sub 2/. The two series of complexes are characterized on the basis of mass spectral, IR, UV-visible, and NMR data. The crystal structure of the title compound has been determined by X-ray diffraction methods: (OEP)Th(acac)/sub 2/, C/sub 46/H/sub 58/N/sub 4/O/sub 4/Th; M/sub r/ = 963; triclinic, P anti 1; a = 9.493 (7), b = 21.185 (5), c = 24.331 (7) A; ..cap alpha.. = 104.18 (2), ..beta.. = 96.11 (4), ..gamma.. = 92.35 (4)/sup 0/; V = 4705 A/sup 3/; d/sub calcd/ = 1.359 g cm/sup -3/; Z = 4; T = 298 K. A total of 9019 intensities were measured on a CAD 4 Enraf-Nonius diffractometer in the omega-2 theta scan mode with monochromatized Mo K..cap alpha.. radiation (1.5 < theta < 20/sup 0/). The crystal structure was refined to a conventional R(F) = 0.047 for 5323 reflections having sigma (I)/I < 0.33. The thorium atom is octacoordinated by the four porphyrin nitrogen atoms and by the four oxygen atoms of the two acetylacetonato groups. 18 references, 2 figures, 8 tables.

  9. A rare tetranuclear thorium(IV) μ4 -oxo cluster and dinuclear thorium(IV) complex assembled by carbon-oxygen bond activation of 1,2-dimethoxyethane (DME).

    PubMed

    Travia, Nicholas E; Scott, Brian L; Kiplinger, Jaqueline L

    2014-12-15

    The synthesis and X-ray crystal structure of two new multinuclear thorium complexes are reported. The tetranuclear μ4 -oxo cluster complex Th4 (μ4 -O)(μ-Cl)2 I6 [κ(2) (O,O')-μ-O(CH2 )2 OCH3 ]6 and the dinuclear complex Th2 I5 [κ(2) (O,O')-μ-O(CH2 )2 OCH3 ]3 (DME) (DME=dimethoxyethane) are formed by CO bond activation of 1,2-dimethoxyethane (DME) mediated by thorium iodide complexes.

  10. Performance of Thorium-Based Mixed Oxide Fuels for the Consumption of Plutonium in Current and Advanced Reactors

    SciTech Connect

    Weaver, Kevan Dean; Herring, James Stephen

    2003-07-01

    A renewed interest in thorium-based fuels has arisen lately based on the need for proliferation resistance, longer fuel cycles, higher burnup, and improved waste form characteristics. Recent studies have been directed toward homogeneously mixed, heterogeneously mixed, and seed-and-blanket thorium-uranium oxide fuel cycles that rely on "in situ" use of the bred-in 233U. However, due to the higher initial enrichment required to achieve acceptable burnups, these fuels are encountering economic constraints. Thorium can nevertheless play a large role in the nuclear fuel cycle, particularly in the reduction of plutonium inventories. While uranium-based mixed-oxide (MOX) fuel will decrease the amount of plutonium in discharged fuel, the reduction is limited due to the breeding of more plutonium (and higher actinides) from the 238U. Here, we present calculational results and a comparison of the potential burnup of a thorium-based and uranium-based mixed-oxide fuel in a light water reactor. Although the uranium-based fuels outperformed the thorium-based fuels in achievable burnup, a depletion comparison of the initially charged plutonium (both reactor and weapons grade) showed that the thorium-based fuels outperformed the uranium-based fuels by more that a factor of 2, where >70% of the total plutonium in the thorium-based fuel is consumed during the cycle. This is significant considering that the achievable burnups of the thorium-based fuels were 1.4 to 4.6 times less than the uranium-based fuels for similar plutonium enrichments. For equal specific burnups of ~60 MWd/kg (i.e., using variable plutonium weight percentages to give the desired burnup), the thorium-based fuels still outperform the uranium-based fuels by more than a factor of 2, where the total plutonium consumption in a three-batch, 18-month cycle was 60 to 70%. This is fairly significant considering that 10 to 15% (by weight) more plutonium is needed in the thorium-based fuels as compared to the uranium

  11. Use of /sup 238/Th as a label in the study of the distribution of thorium in extraction processes

    SciTech Connect

    Naumov, M.A.; Petrov, A.M.; Ragimov, T.K.; Timoshin, V.I.

    1987-03-01

    A ..gamma..-spectrometric method was developed for monitoring the distribution of thorium in products of extraction technology using /sup 228/Th as the label. Gamma radiation with an energy of 238.6 keV, emitted by /sup 212/Pb, a daughter nuclide of /sup 228/Th, was recorded with a semiconductor ..gamma.. spectrometer. On account of the disruption of the radioactive equilibrium between /sup 228/Th and its daughter nuclides during extraction, they measured the activity of /sup 212/Pb on the second and fourth days after extraction. The method permits a determination of the fraction of thorium in the organic phase of the extraction process from 2 to 50% with a relative error from 30 to 4% at the confidence level P = 0.95. Thorium fractions in the aqueous phase of the extraction process in the range from 50 to 98% were determined with a relative error from 7 to 0.6% at P = 0.95.

  12. Thorium(IV) removal from aqueous medium by citric acid treated mangrove endophytic fungus Fusarium sp. #ZZF51.

    PubMed

    Yang, S K; Tan, N; Yan, X M; Chen, F; Long, W; Lin, Y C

    2013-09-15

    Thorium(IV) biosorption is investigated by citric acid treated mangrove endophytic fungus Fussarium sp. #ZZF51 (CA-ZZF51) from South China Sea. The biosorption process was optimized at pH 4.5, equilibrium time 90 min, initial thorium(IV) concentration 50 mg L(-1) and adsorbent dose 0.6 g L(-1) with 90.87% of removal efficiency and 75.47 mg g(-1) of adsorption capacity, which is obviously greater than that (11.35 mg g(-1)) of the untreated fungus Fussarium sp. #ZZF51 for thorium(IV) biosorption under the condition of optimization. The experimental data are analyzed by using isotherm and kinetic models. Kinetic data follow the pseudo-second-order model and equilibrium data agree very well with the Langmuir model. In addition, FTIR analysis indicates that hydroxyl, amino, and carbonyl groups act as the important roles in the adsorption process.

  13. Approche de prise en charge du trouble du spectre de l’autisme

    PubMed Central

    Lee, Patrick F.; Thomas, Roger E.; Lee, Patricia A.

    2015-01-01

    Résumé Objectif Se pencher sur les critères diagnostiques du trouble du spectre de l’autisme (TSA) comme les définit le Manuel diagnostique et statistique des troubles mentaux, cinquième édition (DSM-V), et concevoir une approche de prise en charge du TSA à l’aide du cadre CanMEDS–Médecine familiale (CanMEDS-MF). Sources d’information Le DSM-V, publié par l’American Psychiatric Association en mai 2013, énonce de nouveaux critères diagnostiques du TSA. Le cadre CanMEDS-MF du Collège des médecins de famille du Canada fournit un plan d’orientation pour la prise en charge complexe du TSA. Nous avons utilisé des données recueillies par le Centers for Disease Control and Prevention afin de déterminer la prévalence du TSA, ainsi que la revue systématique et méta-analyse détaillée effectuée par le National Institute for Health and Care Excellence du R.-U. pour ses lignes directrices sur le TSA dans le but d’évaluer les données probantes issues de plus de 100 interventions. Message principal Selon les données du Centers for Disease Control and Prevention, la prévalence du TSA se chiffrait à 1 sur 88 en 2008 aux États-Unis. La classification du TSA dans la quatrième édition du DSM incluait l’autisme, le syndrome d’Asperger, le trouble envahissant du développement et le trouble désintégratif de l’enfance. La dernière révision du DSM-V réunit tous ces troubles sous la mention TSA, avec différents niveaux de sévérité. La prise en charge du TSA est complexe; elle exige les efforts d’une équipe multidisciplinaire ainsi que des soins continus. Les rôles CanMEDS-MF fournissent un cadre de prise en charge. Conclusion Les médecins de famille sont au cœur de l’équipe de soins multidisciplinaire pour le TSA, et le cadre CanMEDS-MF tient lieu de plan détaillé pour guider la prise en charge d’un enfant atteint de TSA et aider la famille de cet enfant.

  14. PWR core design, neutronics evaluation and fuel cycle analysis for thorium-uranium breeding recycle

    SciTech Connect

    Bi, G.; Liu, C.; Si, S.

    2012-07-01

    This paper was focused on core design, neutronics evaluation and fuel cycle analysis for Thorium-Uranium Breeding Recycle in current PWRs, without any major change to the fuel lattice and the core internals, but substituting the UOX pellet with Thorium-based pellet. The fuel cycle analysis indicates that Thorium-Uranium Breeding Recycle is technically feasible in current PWRs. A 4-loop, 193-assembly PWR core utilizing 17 x 17 fuel assemblies (FAs) was taken as the model core. Two mixed cores were investigated respectively loaded with mixed reactor grade Plutonium-Thorium (PuThOX) FAs and mixed reactor grade {sup 233}U-Thorium (U{sub 3}ThOX) FAs on the basis of reference full Uranium oxide (UOX) equilibrium-cycle core. The UOX/PuThOX mixed core consists of 121 UOX FAs and 72 PuThOX FAs. The reactor grade {sup 233}U extracted from burnt PuThOX fuel was used to fabrication of U{sub 3}ThOX for starting Thorium-. Uranium breeding recycle. In UOX/U{sub 3}ThOX mixed core, the well designed U{sub 3}ThOX FAs with 1.94 w/o fissile uranium (mainly {sup 233}U) were located on the periphery of core as a blanket region. U{sub 3}ThOX FAs remained in-core for 6 cycles with the discharged burnup achieving 28 GWD/tHM. Compared with initially loading, the fissile material inventory in U{sub 3}ThOX fuel has increased by 7% via 1-year cooling after discharge. 157 UOX fuel assemblies were located in the inner of UOX/U{sub 3}ThOX mixed core refueling with 64 FAs at each cycle. The designed UOX/PuThOX and UOX/U{sub 3}ThOX mixed core satisfied related nuclear design criteria. The full core performance analyses have shown that mixed core with PuThOX loading has similar impacts as MOX on several neutronic characteristic parameters, such as reduced differential boron worth, higher critical boron concentration, more negative moderator temperature coefficient, reduced control rod worth, reduced shutdown margin, etc.; while mixed core with U{sub 3}ThOX loading on the periphery of core has no

  15. Thorium and rare earth minerals in the Powderhorn district, Gunnison County, Colorado

    USGS Publications Warehouse

    Olson, Jerry C.; Wallace, Stewart R.

    1954-01-01

    Thorium has been found since 1949 in at least 33 deposits in an area 6 miles wide and 20 miles long in the Powderhorn district, Gunnison County, Colo. The district is composed largely of pre-Jurassic metamorphic and igneous rocks, which are chiefly if not entirely pre-Cambrian in age. The metamorphic and igneous rocks are overlain by sandstone of the Morrison formation of Jurassic age, and by volcanic rocks of the Alboroto group and Hinsdale formation of Miocene and Pliocene (?) age, respectively. The thorium deposits occur in or near alkalic igneous rocks in which such elements as titanium, rare earths, barium, strontium, and niobium occur in greater-than-average amounts. The greatest mass of the alkalic igneous rocks the Iron Hill composite stoc,- occupies an area of 12 square miles in the southeastern part of the district. The age of the thorium deposits, like that of the alkalic igneous rocks, is not known other than pre-Jurassic. The thorium veins and mineralized shear zones range from a few inches to 18 feet in thickness and from a few feet to 3,500 feet in length. The veins are composed of calcite,.dolomite, siderite, ankerite, quartz, barite, pyrite, sphalerite, galena, goethite,. apatite, alkali feldspar, and many other minerals. The thorium occurs at least partly in thorite or hydrothorite. Sparse xenotime has been tentatively identified in one deposit. Several minerals containing rare earths of the cerium group as major constituents are found in carbonate veins near Iron Hill. Bastnaesite has been identified by X-ray methods, and cerite and synchisite are probably present also.The fluorapatite in some veins and in parts of the carbonate rock mass that occupies 2 square miles in the central part of the Iron Hill complex contains rare earths of the cerium group, generally in amounts of a fraction of a percent of the rock. The radioactivity of the deposits appears to be due almost entirely to thorium and its daughter products The ThO2 content of selected

  16. The distribution of uranium and thorium in granitic rocks of the basin and range province, Western United States

    USGS Publications Warehouse

    McNeal, J.M.; Lee, D.E.; Millard, H.T.

    1981-01-01

    Some secondary uranium deposits are thought to have formed from uranium derived by the weathering of silicic igneous rocks such as granites, rhyolites, and tuffs. A regional geochemical survey was made to determine the distribution of uranium and thorium in granitic rocks of the Basin and Range province in order to evaluate the potential for secondary uranium occurrences in the area. The resulting geochemical maps of uranium, thorium, and the Th:U ratio may be useful in locating target areas for uranium exploration. The granites were sampled according to a five-level, nested, analysis-of-variance design, permitting estimates to be made of the variance due to differences between:(1) two-degree cells; (2) one-degree cells; (3) plutons; (4) samples; and (5) analyses. The cells are areas described in units of degrees of latitude and longitude. The results show that individual plutons tend to differ in uranium and thorium concentrations, but that each pluton tends to be relatively homogeneous. Only small amounts of variance occur at the two degree and the between-analyses levels. The three geochemical maps that were prepared are based on one-degree cell means. The reproducibility of the maps is U > Th ??? Th:U. These geochemical maps may be used in three methods of locating target areas for uranium exploration. The first method uses the concept that plutons containing the greatest amounts of uranium may supply the greatest amounts of uranium for the formation of secondary uranium occurrences. The second method is to examine areas with high thorium contents, because thorium and uranium are initially highly correlated but much uranium could be lost by weathering. The third method is to locate areas in which the plutons have particularly high Th:U ratios. Because uranium, but not thorium, is leached by chemical weathering, high Th:U ratios suggest a possible loss of uranium and possibly a greater potential for secondary uranium occurrences to be found in the area. ?? 1981.

  17. Prediction of new high pressure structural sequence in thorium carbide: A first principles study

    SciTech Connect

    Sahoo, B. D. Joshi, K. D.; Gupta, Satish C.

    2015-05-14

    In the present work, we report the detailed electronic band structure calculations on thorium monocarbide. The comparison of enthalpies, derived for various phases using evolutionary structure search method in conjunction with first principles total energy calculations at several hydrostatic compressions, yielded a high pressure structural sequence of NaCl type (B1) → Pnma → Cmcm → CsCl type (B2) at hydrostatic pressures of ∼19 GPa, 36 GPa, and 200 GPa, respectively. However, the two high pressure experimental studies by Gerward et al. [J. Appl. Crystallogr. 19, 308 (1986); J. Less-Common Met. 161, L11 (1990)] one up to 36 GPa and other up to 50 GPa, on substoichiometric thorium carbide samples with carbon deficiency of ∼20%, do not report any structural transition. The discrepancy between theory and experiment could be due to the non-stoichiometry of thorium carbide samples used in the experiment. Further, in order to substantiate the results of our static lattice calculations, we have determined the phonon dispersion relations for these structures from lattice dynamic calculations. The theoretically calculated phonon spectrum reveal that the B1 phase fails dynamically at ∼33.8 GPa whereas the Pnma phase appears as dynamically stable structure around the B1 to Pnma transition pressure. Similarly, the Cmcm structure also displays dynamic stability in the regime of its structural stability. The B2 phase becomes dynamically stable much below the Cmcm to B2 transition pressure. Additionally, we have derived various thermophysical properties such as zero pressure equilibrium volume, bulk modulus, its pressure derivative, Debye temperature, thermal expansion coefficient and Gruneisen parameter at 300 K and compared these with available experimental data. Further, the behavior of zero pressure bulk modulus, heat capacity and Helmholtz free energy has been examined as a function temperature and compared with the experimental data of Danan [J

  18. Uranium-thorium isotope geochemistry of saline ground waters from central Missouri

    SciTech Connect

    Banner, J.L.; Chen, J.H.; Wasserburg, G.J.

    1989-03-01

    The isotopic and elemental distributions of uranium and thorium were examined in a suite of saline ground waters from central Missouri using mass spectrometric techniques. The waters were sampled from natural springs and artesian wells in Mississippian and Ordovician aquifers and have a wide range in salinity (5 to 26 /per thousand/), deltaD (/minus/108 to /minus/45 /per thousand/), and delta/sup 18/O (/minus/14.7 to /minus/6.5 /per thousand/) values. The suite of samples has a large range in /sup 238/U (50 to 200 x 10/sup /minus/12/g/g) and /sup 232/Th (0.3 to 9.1 x 10/sup /minus/12/g/g) concentrations and extremely high /sup 234/U//sup 238/U activity ratios ranging from 2.15 to 16.0. These isotopic compositions represent pronounced uranium-series disequilibrium compared with the value of modern seawater (1.15) or the equilibrium value (1.00). For such /sup 234/U-enriched waters, /sup 234/U//sup 238/U isotope ratios can be determined with a precision of /+-/ 10 /per thousand/ (2sigma) on 10 mL of sample and less than /+-/5 /per thousand/ on 100 mL. In contrast to the large /sup 234/U enrichments, /sup 230/Th//sup 238/U activity ratios in the ground waters are significantly lower than the equilibrium value. The more saline samples have markedly higher /sup 234/U//sup 238/U activity ratios and lower deltaD and delta/sup 18/O values. Unfiltered and filtered (< 0.1 ..mu..m) aliquots of a saline sample have the same isotopic composition and concentration of uranium, indicating uranium essentially occurs entirely as a dissolved species. The filtered/unfiltered concentration ratio for thorium in this sample is 0.29, demonstrating the predominant association of thorium with particulates.

  19. Natural uranium and thorium isotopes in sediment cores off Malaysian ports

    NASA Astrophysics Data System (ADS)

    Yusoff, Abdul Hafidz; Sabuti, Asnor Azrin; Mohamed, Che Abd Rahim

    2015-06-01

    Sediment cores collected from three Malaysian marine ports, namely, Kota Kinabalu, Labuan and Klang were analyzed to determine the radioactivities of 234U, 238U, 230Th, 232Th and total organic carbon (TOC) content. The objectives of this study were to determine the factors that control the activity of uranium isotopes and identify the possible origin of uranium and thorium in these areas. The activities of 234U and 238U show high positive correlation with TOC at the middle of sediment core from Kota Kinabalu port. This result suggests that activity of uranium at Kota Kinabalu port was influenced by organic carbon. The 234U/238U value at the upper layer of Kota Kinabalu port was ≥1.14 while the ratio value at Labuan and Klang port was ≤ 1.14. These results suggest a reduction process occurred at Kota Kinabalu port where mobile U(VI) was converted to immobile U(IV) by organic carbon. Therefore, it can be concluded that the major input of uranium at Kota Kinabalu port is by sorptive uptake of authigenic uranium from the water column whereas the major inputs of uranium to Labuan and Klang port are of detrital origin. The ratio of 230Th/232Th was used to estimate the origin of thorium. Low ratio value (lt; 1.5) at Labuan and Klang ports support the suggestion that thorium from both areas were come from detrital input while the high ratio (> 1.5) of 230Th/232Th at Kota Kinabalu port suggest the anthropogenic input of 230Th to this area. The source of 230Th is probably from phosphate fertilizers used in the oil-palm cultivation in Kota Kinabalu that is adjacent to the Kota Kinabalu port.

  20. Contents of cesium, iodine, strontium, thorium, and uranium in selected human organs of adult asian population.

    PubMed

    Iyengar, G V; Kawamura, H; Dang, H S; Parr, R M; Wang, J W; Cho, S Y; Natera, E S

    2004-08-01

    Contents of cesium, iodine, strontium, thorium, and uranium in some selected human organs were estimated for adult Asian population using data obtained in four Asian countries: China, India, Philippines, and Republic of Korea, as part of a Coordinated Research Program of the International Atomic Energy Agency on "Ingestion and Organ contents of elements of importance in radiation protection." These countries together represent more than 40% of the world population. Highly sensitive analytical techniques were employed to measure cesium in skeletal muscle, iodine in thyroid, strontium in skeleton, thorium and uranium in skeleton, liver, kidneys, and lungs where, in comparison to other organs, these elements are present in higher concentrations. The organ contents for adult Asian population, when compared with the corresponding data proposed for Reference Man by International Commission on Radiological Protection (ICRP), showed about 40 times lower kidneys content and about 10 times lower skeleton content of uranium. The content of thorium in skeleton for Asian population was also half of the ICRP Reference Man value. Interestingly, organ contents for the other elements such as iodine in thyroid, cesium in skeletal muscle, and strontium in skeleton were comparable for Asian and the Caucasian population (represented by ICRP Reference Man). Organ contents for these elements were also calculated by applying the new ICRP models of these elements to their daily intakes. The comparison of the calculated and measured organ contents showed that despite uncertainties in the organ content values arising due to the inter-country variations in daily dietary intakes, the contents were within a factor of two to three. This observation is significant since human data both on organ contents and ingestion were obtained at environmental level of intakes. The study suggests that currently available ICRP models for these elements are quite realistic.

  1. Determination of thorium, uranium and potassium elemental concentrations in surface soils in Cyprus.

    PubMed

    Tzortzis, Michalis; Tsertos, Haralabos

    2004-01-01

    A comprehensive study was conducted to determine thorium, uranium and potassium elemental concentrations in surface soils throughout the accessible area of Cyprus using high-resolution gamma-ray spectrometry. A total of 115 soil samples was collected from all over the bedrock surface of the island based on the different lithological units of the study area. The soil samples were air-dried, sieved through a fine mesh, sealed in 1000-ml plastic Marinelli beakers, and measured in the laboratory in terms of their gamma radioactivity for a counting time of 18 h each. From the measured gamma-ray spectra, elemental concentrations were determined for thorium (range from 2.5 x 10(-3) to 9.8 microg g(-1)), uranium (from 8.1 x 10(-4) to 3.2 microg g(-1)) and potassium (from 1.3 x 10(-4) to 1.9%). The arithmetic mean values (A.M. +/- S.D.) calculated from all samples are: (1.2+/-1.7 microg g(-1)), (0.6+/-0.7) microg g(-1), and (0.4+/-0.3%), for thorium, uranium and potassium, respectively, which are by a factor of three-six lower than the world average values of 7.4 microg g(-1) (Th), 2.8 microg g(-1) (U) and 1.3% (K) derived from all data available worldwide. The best-fitting relation between the concentrations of Th and K versus U and also of K versus Th, is essentially of linear type with a correlation coefficient of 0.93, 0.84 and 0.90, respectively. The Th/U, K/U and K/Th ratios (slopes) extracted are equal to 2.0, 2.8 x 10(3) and 1.4 x 10(3), respectively.

  2. The Aqueous Complexation of Thorium with Citrate under Neutral to Basic Conditions

    SciTech Connect

    Felmy, Andrew R; Cho, Herman M; Dixon, David A; Xia, Yuanxian; Hess, Nancy J; Wang, Zheming

    2006-04-20

    The aqueous complexation of thorium with citrate was investigated under neutral to basic conditions and over a broad range of ionic strengths. The solubility data for ThO2(am) as a function of citrate concentration indicate the presence of stable species with citrate-to-metal ratios of between two to three. The dependence of the ThO2(am) solubilities on hydrogen ion concentration can also be readily explained by the classical assumption of hydrolysis of the central Th(IV) ion to form mixed thorium-hydroxide-citrate complexes. 13C NMR spectra of the species in solution confirm that the citrate-to-metal ratio of the species in solution is between two and three and show that the citrate attaches to the metal in a bidentate fashion through oxygens on the -carboxylate and -alkoxyl groups, rather than through the carboxylate groups. The 13C NMR spectra, as well as a density functional theory (DFT) electronic structure study of the presumptive complexes, suggests that the associated α-hydroxyl proton can be displaced during complex formation. These findings indicate an alternative explanation for the observed changes in solubility as a function of hydrogen ion concentration, the displacement of protons from the citrate alkoxyl groups via metal binding. Removal of protons from the alkoxyl groups or hydrolysis of the central Th(IV) cannot be distinguished by thermodynamic measurements, however the species with the α-hydroxyl proton removed (i.e., ThOH(Cit)25- and Th(Cit)38-) would appear to better represent the microscopic binding. Apparent equilibrium constants for the solution phase reactions of these species and the hydrous thorium oxide have been calculated as a function of ionic strength.

  3. Les plaies du tendon patellaire

    PubMed Central

    Mechchat, Atif; Elidrissi, Mohammed; Mardy, Abdelhak; Elayoubi, Abdelghni; Shimi, Mohammed; Elibrahimi, Abdelhalim; Elmrini, Abdelmajid

    2014-01-01

    Les plaies du tendon patellaire sont peu fréquentes et sont peu rapportés dans la littérature, contrairement aux ruptures sous cutanées. Les sections du tendon patellaire nécessitent une réparation immédiate afin de rétablir l'appareil extenseur et de permettre une récupération fonctionnelle précoce. A travers ce travail rétrospectif sur 13 cas, nous analysons les aspects épidémiologiques, thérapeutiques et pronostiques de ce type de pathologie en comparant différents scores. L’âge moyen est de 25 ans avec une prédominance masculine. Les étiologies sont dominées par les accidents de la voie publique (68%) et les agressions par agent tranchant (26%) et contendant (6 %). Tous nos patients ont bénéficié d'un parage chirurgical avec suture tendineuse direct protégée par un laçage au fils d'aciers en légère flexion. La rééducation est débutée après sédation des phénomènes inflammatoires. Au dernier recul les résultats sont excellents et bon à 92%. Nous n'avons pas noté de différence de force musculaire et d'amplitude articulaire entre le genou sain et le genou lésé. Les lésions ouvertes du tendon patellaire est relativement rare. La prise en charge chirurgicale rapide donne des résultats assez satisfaisants. La réparation est généralement renforcée par un semi-tendineux, synthétique ou métallique en forme de cadre de renfort pour faciliter la réadaptation et réduire le risque de récidive après la fin de l'immobilisation. PMID:25170379

  4. Selective two-step titration of thorium by sulfate displacement of the diethylenetriaminepentaacetic acid complex

    SciTech Connect

    Kiefer, P.

    1980-07-01

    Thorium and other metals are complexed with excess diethylenetriaminepentaacetic acid (DTPA) at pH 1.4, the excess DTPA is titrated with Bi(III) to a xylenol orange end point, sulfate is added to complex Th(IV), and the displaced DTPA again is titrated with Bi(III). Of 61 metal ions and nonmetal anions tested, only Ga(III), Sc(III), tungstate, citrate, oxalate, and thiosulfate interfere seriously. Lesser interferences are In(III), Zr(IV), V(IV), and permanganate. The standard deviation is 2 ..mu..g for 56 to 840 ..mu..g Th.

  5. The effect of yttrium and thorium on the oxidation behavior of Ni-Cr-Al alloys

    NASA Technical Reports Server (NTRS)

    Kumar, A.; Douglass, D. L.; Nasrallah, M.

    1974-01-01

    The investigation reported included a determination of the optimum composition of a Ni-Cr-Al ternary alloy with respect to oxidation resistance and minimum film-spalling tendencies. Yttrium and thorium in small amounts were added to the ternary alloy and an investigation of the oxidation mechanism and the oxide scale adherence was conducted. It was found that the oxidation mechanism of Ni-Cr-Al ternary alloys depends upon the composition of the alloy as well as the time, oxygen pressure, and temperature of oxidation.

  6. Ab initio modeling of point defects, self-diffusion, and incorporation of impurities in thorium

    NASA Astrophysics Data System (ADS)

    Daroca, D. Pérez

    2017-02-01

    Research on Generation-IV nuclear reactors has boosted the investigation of thorium as nuclear fuel. By means of first-principles calculations within the framework of density functional theory, structural properties and phonon dispersion curves of Th are obtained. These results agreed very well with previous ones. The stability and formation energies of vacancies, interstitial and divacancies are studied. It is found that vacancies are the energetically preferred defects. The incorporation energies of He, Xe, and Kr atoms in Th defects are analyzed. Self-diffusion, migration paths and activation energies are also calculated.

  7. Crystal Growth of: Yttrium Phosphate Ce3+:Thorium Dioxide Ce3+:Lanthanum Aluminate.

    DTIC Science & Technology

    1982-10-01

    OF S7ANOARDS1963-A c; CRYSTAL WRONTH Or: gIUm PRSHATI Ce :TUORIUK DIOXIDZ Ce * LANTHANUM ALUMIRATH PHILIPS LABO0MIORXES A Division of North American...PERFORMING ORG. REPORT NUMBER Ce : LANTHANUM ALUMINATE 7. AUTHOR(&) S. CONTRACT OR GRANT NUMOER(a) W. Zwicker E. Abelaf S. Colak T. Kovats N00014-79-C-0180...Thorium Oxide (Ce :ThO )..........................16 3.3 Ce3 : Lanthanum Aluminate (Ce3 :LaA1O 3) ........... ........ 21 4. CRYSTAL EVALUATION

  8. Search for the electric dipole moment of the electron with thorium monoxide

    NASA Astrophysics Data System (ADS)

    Hutzler, Nicholas; Campbell, Wes; Gurevich, Yulia; Hess, Paul; Kirilov, Emil; Parsons, Maxwell; Petrik, Elizabeth; Spaun, Benjamin; Vutha, Amar; Demille, David; Gabrielse, Gerald; Doyle, John

    2010-03-01

    The thorium monoxide molecule (ThO) in its metastable H state is a promising system for measuring or improving the limit on the permanent electric dipole moment of the electron (eEDM). We report on progress towards using ThO to measure the eEDM with a high-flux molecular beam. A cryogenic beam source has been constructed and is undergoing characterization and optimization. We also report on some preliminary realizations of state preparation and detection of laser-induced blue-shifted fluorescence from the EDM-sensitive H state.

  9. The effect of yttrium and thorium on the oxidation behavior of Ni-Cr-Al alloys

    NASA Technical Reports Server (NTRS)

    Kumar, A.; Douglass, D. L.; Nasrallah, M.

    1974-01-01

    The investigation reported included a determination of the optimum composition of a Ni-Cr-Al ternary alloy with respect to oxidation resistance and minimum film-spalling tendencies. Yttrium and thorium in small amounts were added to the ternary alloy and an investigation of the oxidation mechanism and the oxide scale adherence was conducted. It was found that the oxidation mechanism of Ni-Cr-Al ternary alloys depends upon the composition of the alloy as well as the time, oxygen pressure, and temperature of oxidation.

  10. Thorium binding by biochar fibres derived from Luffa Cylindrica after controlled surface oxidation

    NASA Astrophysics Data System (ADS)

    Liatsou, Ioanna; Christodoulou, Eleni; Paschalidis, Ioannis

    2017-04-01

    Controlled surface modification of biochar fibres derived from Luffa Cylindrica sponges has been carried out by nitric acid and the degree of oxidation could be controlled by changing the acid concentration or the reaction time. The extent of surface oxidation has been quantified by acid-base titration and FTIR-spectroscopy. Furthermore, thorium binding has been studied as a function of various parameters and the experimental results show that even under strong acidic conditions the relative sorption is above 70% and the sorption capacity of the biochar fibres for Th(IV) at pH 3 is qmax= 70 gṡkg-1.

  11. Rubidium-strontium, uranium, and thorium-lead dating of lunar material.

    PubMed

    Gopalan, K; Kaushal, S; Lee-Hu, C; Wetherill, G W

    1970-01-30

    Rubidiuom and stronztiulm concentrations and strontium isotopic compositions have been measutred on whole rock samples and density fractions of microgabbro. Density fractionis on two rocks define isochrons of 3400 and 4500 million years with large uincertainties owing to low enrichment of radiogenic strontium. Lead from fine surface material is highly radiogenic. An age of 4750 million years has been calculated from the ratio of (207)Pb/(206)Pb. The concentrations of uiranium, thorium, and lead isotopes are consistent with the evolution of lead in a 4700-million-year-old closed system characterized by the ratios of uranium to lead and of thoriunm to lead in this sutrface material.

  12. Decorporating efficacy of catecholaminocarboxylate chelating agents for thorium-234 and protective effects on associated radiation injury.

    PubMed

    Chen, Hh; Luo, Mc; Sun, Mz; Hu, Yx; Wang, Yh; Jin, My; Cheng, Wy

    2005-04-01

    The aim was to identify the decorporation and anti-oxidation efficacy of prompt and delayed consecutive administration of the catecholicpolyaminopolycarboxylate ligands 9501 and 7601 for radiothorium in vivo. The chelating agents 9501 or 7601 were administered intramuscularly to ICR mice 3 min or 3 days after intraperitoneal injection of 30 MBq kg(-1) (234)Th-citrate for 3 consecutive days. The animals were killed 4 or 5 days after administration of the chelating agents, respectively. The (234)Th radioactivity in the whole-body and its retention in liver and skeleton were determined. Malondialdehyde (MDA) production, as an index of (234)Th-induced lipid peroxidation in bone marrow and liver, was assayed and the number of bone marrow nucleated cells (NBMNC) were counted. The pathological changes of bone marrow and liver tissue were observed. CaNa(3)-diethylenetriaminepentaacetate (DTPA) and vitamin E were used as controls. The competitive ability of 9501 and 7601 to mobilize thorium with bovine serum albumin (BSA) was studied. Their inhibitory effect on superoxide anion radicals was measured by electron spin resonance. When promptly injected, 9501 or 7601 were superior to CaNa(3)-DTPA for reducing (234)Th retention in mouse. Their different bioactivity for decorporation of (234)Th was consistent with their competitive ability to mobilize thorium with BSA. Although the removal effectiveness of 9501 and 7601, given by delayed injection, was lower than that of the prompt administration, they could inhibit (234)Th-induced lipid peroxidation. This caused significant reductions of MDA content in bone marrow and liver and markedly ameliorated histological changes to bone marrow and liver tissue in (234)Th-treated mice. Their protective effects were better than CaNa(3)-DTPA and vitamin E. 9501 and 7601 could directly scavenge O(.-)(2). Their effects as O(.-)(2) scavengers were very significant. The chelating agents 9501 and 7601 are able to remove thorium as effectively as

  13. Calcium thorium phosphate (Whitlockite-type mineral). Synthesis and structure refinement

    SciTech Connect

    Orlova, A. I.; Khainakov, S. A.; Loginova, E. E.; Oleneva, T. A.; Garcia Granda, S.; Kurazhkovskaya, V. S.

    2009-07-15

    The crystal structure of a new calcium thorium phosphate has been refined by the full-profile Rietveld method using X-ray powder diffraction data. The sample has been synthesized by the sol-gel technique. The phosphate has been identified by X-ray powder diffraction and IR spectroscopy. The refined composition is represented by the formula Ca{sub 10.26}Th{sub 0.12}(PO{sub 4}){sub 7}. The CaO{sub n} and PO{sub 4} polyhedra are distorted compared to the corresponding polyhedra in the basic compound {beta}-Ca{sub 3}(PO{sub 4}){sub 2}.

  14. Non-Proliferative, Thorium-Based, Core and Fuel Cycle for Pressurized Water Reactors

    SciTech Connect

    Todosow M.; Todosow M.; Raitses, G. Galperin, A.

    2009-07-12

    Two of the major barriers to the expansion of worldwide adoption of nuclear power are related to proliferation potential of the nuclear fuel cycle and issues associated with the final disposal of spent fuel. The Radkowsky Thorium Fuel (RTF) concept proposed by Professor A. Radkowsky offers a partial solution to these problems. The main idea of the concept is the utilization of the seed-blanket unit (SBU) fuel assembly geometry which is a direct replacement for a 'conventional' assembly in either a Russian pressurized water reactor (VVER-1000) or a Western pressurized water reactor (PWR). The seed-blanket fuel assembly consists of a fissile (U) zone, known as seed, and a fertile (Th) zone known as blanket. The separation of fissile and fertile allows separate fuel management schemes for the thorium part of the fuel (a subcritical 'blanket') and the 'driving' part of the core (a supercritical 'seed'). The design objective for the blanket is an efficient generation and in-situ fissioning of the U233 isotope, while the design objective for the seed is to supply neutrons to the blanket in a most economic way, i.e. with minimal investment of natural uranium. The introduction of thorium as a fertile component in the nuclear fuel cycle significantly reduces the quantity of plutonium production and modifies its isotopic composition, reducing the overall proliferation potential of the fuel cycle. Thorium based spent fuel also contains fewer higher actinides, hence reducing the long-term radioactivity of the spent fuel. The analyses show that the RTF core can satisfy the requirements of fuel cycle length, and the safety margins of conventional pressurized water reactors. The coefficients of reactivity are comparable to currently operating VVER's/PWR's. The major feature of the RTF cycle is related to the total amount of spent fuel discharged for each cycle from the reactor core. The fuel management scheme adopted for RTF core designs allows a significant decrease in the

  15. Search for long-lived isomeric states in neutron-deficient thorium isotopes

    SciTech Connect

    Lachner, J.; Dillmann, I.; Faestermann, T.; Korschinek, G.; Poutivtsev, M.; Rugel, G.

    2008-12-15

    The discovery of naturally occurring long-lived isomeric states (t{sub 1/2}>10{sup 8} yr) in the neutron-deficient isotopes {sup 211,213,217,218}Th[A. Marinov et al., Phys. Rev. C 76, 021303(R) (2007)] was reexamined using accelerator mass spectrometry (AMS). Because AMS does not suffer from molecular isobaric background in the detection system, it is an extremely sensitive technique. Despite our up to two orders of magnitude higher sensitivity we cannot confirm the discoveries of neutron-deficient thorium isotopes and provide upper limits for their abundances.

  16. Analysis of the gamma spectra of the uranium, actinium, and thorium decay series

    SciTech Connect

    Momeni, M.H.

    1981-09-01

    This report describes the identification of radionuclides in the uranium, actinium, and thorium series by analysis of gamma spectra in the energy range of 40 to 1400 keV. Energies and absolute efficiencies for each gamma line were measured by means of a high-resolution germanium detector and compared with those in the literature. A gamma spectroscopy method, which utilizes an on-line computer for deconvolution of spectra, search and identification of each line, and estimation of activity for each radionuclide, was used to analyze soil and uranium tailings, and ore.

  17. Commercial food irradiation

    SciTech Connect

    Black, E.F.; Libby, L.M.

    1983-06-01

    Food irradiation is discussed. Irradiation exposes food to gamma rays from a cobalt-60 or a cesium-137 source, or to high-energy electrons emitted by an electron accelerator. A major advantage is that food can be packaged either before or after treatment. FDA regulations with regard to irradiation are discussed. Comments on an 'Advance Notice' on irradiation, published by the FDA in 1981 are summarized.

  18. Dounreay PFR irradiation history for the joint US/UK actinide sample exposures

    SciTech Connect

    Raman, S.; Murphy, B.D.; Nestor, C.W. Jr.

    1995-07-01

    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.

  19. DU-127090 Solvay/H Lundbeck.

    PubMed

    Wolf, William

    2003-01-01

    DU-127090 is a mixed dopamine antagonist/serotonin agonist in development by Solvay and H Lundbeck as a potential treatment for psychosis and schizophrenia, for which it is in phase II clinical trials. In August 2002, phase II trials were ongoing and Lundbeck expected to commence phase III trials in 2003 and file an NDA after 2004. DU-127090 is also under development for Parkinson's disease, for which it is in phase I clinical trials.

  20. IMPACT OF URANIUM AND THORIUM ON HIGH TIO2 CONCENTRATION NUCLEAR WASTE GLASSES

    SciTech Connect

    Fox, K.; Edwards, T.

    2012-01-11

    This study focused on the potential impacts of the addition of Crystalline Silicotitanate (CST) and Monosodium Titanate (MST) from the Small Column Ion Exchange (SCIX) process on the Defense Waste Processing Facility (DWPF) glass waste form and the applicability of the DWPF process control models. MST from the Salt Waste Processing Facility (SWPF) is also considered in the study. The KT08-series of glasses was designed to evaluate any impacts of the inclusion of uranium and thorium in glasses containing the SCIX components. All but one of the study glasses were found to be amorphous by X-ray diffraction (XRD). One of the slowly cooled glasses contained a small amount of trevorite, which is typically found in DWPF-type glasses and had no practical impact on the durability of the glass. The measured Product Consistency Test (PCT) responses for the study glasses and the viscosities of the glasses were well predicted by the current DWPF models. No unexpected issues were encountered when uranium and thorium were added to the glasses with SCIX components.