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Sample records for 232u tsentrobezhnym metodom

  1. Predicting 232U Content in Uranium

    SciTech Connect

    AJ Peurrung

    1999-01-07

    The minor isotope 232U may ultimately be used for detection or confirmation of uranium in a variety of applications. The primary advantage of 232 U as an indicator of the presence of enriched uranium is the plentiful and penetrating nature of the radiation emitted by its daughter radionuclide 208Tl. A possible drawback to measuring uranium via 232U is the relatively high uncertainty in 232U abundance both within and between material populations. An important step in assessing this problem is to ascertain what determines the 232U concentration within any particular sample of uranium. To this end, we here analyze the production and eventual enrichment of 232 U during fuel-cycle operations. The goal of this analysis is to allow approximate prediction of 232 U quantities, or at least some interpretation of the results of 232U measurements. We have found that 232U is produced via a number of pathways during reactor irradiation of uranium and is subsequently concentrated during the later enrichment of the uranium' s 235U Content. While exact calculations are nearly impossible for both the reactor-production and cascade-enrichment parts of the prediction problem, estimates and physical bounds can be provided as listed below and detailed within the body of the report. Even if precise calculations for the irradiation and enrichment were possible, the ultimate 212U concentration would still depend upon the detailed fuel-cycle history. Assuming that a thennal-diffusion cascade is used to produce highly enriched uranium (HEU), dilution of reactor-processed fuel at the cascade input and the long-term holdup of 232U within the cascade both affect the 232U concentration in the product. Similar issues could be expected to apply for the other isotope-separation technologies that are used in other countries. Results of this analysis are listed below: 0 The 232U concentration depends strongly on the uranium enrichment, with depleted uranium (DU) containing between 1600 and 8000 times

  2. Gamma-spectrometric determination of 232U in uranium-bearing materials

    NASA Astrophysics Data System (ADS)

    Zsigrai, Jozsef; Nguyen, Tam Cong; Berlizov, Andrey

    2015-09-01

    The 232U content of various uranium-bearing items was measured using low-background gamma spectrometry. The method is independent of the measurement geometry, sample form and chemical composition. Since 232U is an artificially produced isotope, it carries information about previous irradiation of the material, which is relevant for nuclear forensics, nuclear safeguards and for nuclear reactor operations. A correlation between the 232U content and 235U enrichment of the investigated samples has been established, which is consistent with theoretical predictions. It is also shown how the correlation of the mass ratio 232U/235U vs. 235U content can be used to distinguish materials contaminated with reprocessed uranium from materials made of reprocessed uranium.

  3. Electric dipole moments in {sup 230,232}U and implications for tetrahedral shapes

    SciTech Connect

    Ntshangase, S. S.; Bark, R. A.; Datta, P.; Lawrie, E. A.; Lawrie, J. J.; Lieder, R. M.; Mullins, S. M.; Aschman, D. G.; Mohammed, H.; Stankiewicz, M. A.; Bvumbi, S.; Masiteng, P. L.; Shirinda, O.; Davidson, P. M.; Nieminen, P.; Wilson, A. N.; Dinoko, T. S.; Sharpey-Shafer, J. F.; Elbasher, M. E. A.; Juhasz, K.

    2010-10-15

    The nuclei {sup 230}U and {sup 232}U were populated in the compound nucleus reactions {sup 232}Th({alpha},6n) and {sup 232}Th({alpha},4n), respectively. Gamma rays from these nuclei were observed in coincidence with a recoil detector. A comprehensive set of in-band E2 transitions were observed in the lowest lying negative-parity band of {sup 232}U while one E2 transition was also observed for {sup 230}U. These allowed B(E1;I{sup -{yields}}I{sup +}-1)/B(E2;I{sup -{yields}}I{sup -}-2) ratios to be extracted and compared with systematics. The values are similar to those of their Th and Ra isotones. The possibility of a tetrahedral shape for the negative-parity U bands appears difficult to reconcile with the measured Q{sub 2} values for the isotone {sup 226}Ra.

  4. Analysis of the clustering in 212Po, 218Rn and 232U

    NASA Astrophysics Data System (ADS)

    Ibrahim, T. T.; Wyngaardt, S. M.; Kimene Kaya, B. D. C.

    2017-10-01

    We studied the ground state band properties of 212Po, 218Rn and 232U using the binary cluster model. The nuclei are treated as a 208Pb-core plus a cluster interacting via a local potential of Saxon-Woods type functional form whose parameters are derived from Michigan-3-Yukawa (M3Y) microscopic potential model. Further correction in the internal structure of the hybrid potential model is attributed to the nucleon distribution in the overlap region of the core-cluster system. Overall our calculated results are found to compare favourably well with available experimental data.

  5. Hyperdeformed sub-barrier fission resonances observed in {sup 232}U

    SciTech Connect

    Csige, L.; Csatlos, M.; Gacsi, Z.; Gulyas, J.; Krasznahorkay, A.; Faestermann, T.; Wirth, H.-F.; Habs, D.; Hertenberger, R.; Lutter, R.; Maier, H. J.; Thirolf, P. G.

    2009-07-15

    The fission probability of {sup 232}U has been measured using the {sup 231}Pa({sup 3}He,df) reaction with an energy resolution of 11 keV in the excitation energy region of E*=4.0-6.4 MeV. A number of sub-barrier fission resonances have been observed for the first time in the excitation energy range below E*=4.8 MeV and interpreted as rotational bands with a rotational parameter characteristic to a hyperdeformed nuclear shape (({Dirac_h}/2{pi}){sup 2}/2{theta}=1.96{+-}0.11 keV). The angular distribution of the associated fission fragments was measured to deduce the K value of the rotational bands. The fission barrier parameters of {sup 232}U have been determined by analyzing the overall features of the fission probability. A deep third minimum with an excitation energy of E{sub III}=3.2(2) MeV and rather low inner barrier height of E{sub A}=4.0(3) MeV could be established.

  6. Spectroscopy of 232U in the (p , t ) reaction: More information on 0+ excitations

    NASA Astrophysics Data System (ADS)

    Levon, A. I.; Alexa, P.; Graw, G.; Hertenberger, R.; Pascu, S.; Thirolf, P. G.; Wirth, H.-F.

    2015-12-01

    The excitation spectra in the deformed nucleus 232U have been studied by means of the (p ,t ) reaction, using the Q3D spectrograph facility at the Munich Tandem accelerator. The angular distributions of tritons were measured for 162 excitations seen in the triton spectra up to 3.25 MeV. 0+ assignments are made for 13 excited states by comparison of experimental angular distributions with the calculated ones using the chuck3 code. Assignments up to spin 6+ are made for other states. Sequences of states are selected which can be treated as rotational bands. Moments of inertia have been derived from these sequences, whose values may be considered as evidence of the two- or one-phonon nature of these 0+ excitations. Experimental data are compared with interacting boson model and quasiparticle-phonon model calculations.

  7. Delayed Fission Gamma-ray Characteristics of Th-232 U-233 U-235 U-238 and Pu-239

    SciTech Connect

    Lane, Taylor; Parma, Edward J.

    2015-08-01

    Delayed fission gamma-rays play an important role in determining the time dependent ioniz- ing dose for experiments in the central irradiation cavity of the Annular Core Research Reactor (ACRR). Delayed gamma-rays are produced from both fission product decay and from acti- vation of materials in the core, such as cladding and support structures. Knowing both the delayed gamma-ray emission rate and the time-dependent gamma-ray energy spectrum is nec- essary in order to properly determine the dose contributions from delayed fission gamma-rays. This information is especially important when attempting to deconvolute the time-dependent neutron, prompt gamma-ray, and delayed gamma-ray contribution to the response of a diamond photo-conducting diode (PCD) or fission chamber in time frames of milliseconds to seconds following a reactor pulse. This work focused on investigating delayed gamma-ray character- istics produced from fission products from thermal, fast, and high energy fission of Th-232, U-233, U-235, U-238, and Pu-239. This work uses a modified version of CINDER2008, a transmutation code developed at Los Alamos National Laboratory, to model time and energy dependent photon characteristics due to fission. This modified code adds the capability to track photon-induced transmutations, photo-fission, and the subsequent radiation caused by fission products due to photo-fission. The data is compared against previous work done with SNL- modified CINDER2008 [ 1 ] and experimental data [ 2 , 3 ] and other published literature, includ- ing ENDF/B-VII.1 [ 4 ]. The ability to produce a high-fidelity (7,428 group) energy-dependent photon fluence at various times post-fission can improve the delayed photon characterization for radiation effects tests at research reactors, as well as other applications.

  8. Basic characterization of 233U: Determination of age and 232U content using sector field ICP-MS, gamma spectrometry and alpha spectrometry

    NASA Astrophysics Data System (ADS)

    Ramebäck, H.; Nygren, U.; Lagerkvist, P.; Verbruggen, A.; Wellum, R.; Skarnemark, G.

    2008-03-01

    The possibility to determine the age, i.e. the time since the last chemical separation, of 233U was studied using two fundamentally different measurement techniques: inductively coupled plasma mass spectrometry (ICP-MS) and gamma spectrometry. Moreover, the isotope ratio 232U/233U was measured using both alpha spectrometry and gamma spectrometry. For the two materials analysed, all measurement results were in agreement, i.e. consistent within the combined uncertainties. One of the materials was also measured using gamma spectrometry under field conditions. This measurement was also in agreement with the other results on this material.

  9. Resonance Region Covariance Analysis Method and New Covariance Data for Th-232, U-233, U-235, U-238, and Pu-239

    SciTech Connect

    Leal, Luiz C; Arbanas, Goran; Derrien, Herve; Wiarda, Dorothea

    2008-01-01

    Resonance-parameter covariance matrix (RPCM) evaluations in the resolved resonance region were done for 232Th, 233U, 235U, 238U, and 239Pu using the computer code SAMMY. The retroactive approach of the code SAMMY was used to generate the RPCMs for 233U, 235U. RPCMs for 232Th, 238U and 239Pu were generated together with the resonance parameter evaluations. The RPCMs were then converted in the ENDF format using the FILE32 representation. Alternatively, for computer storage reasons, the FILE32 was converted in the FILE33 cross section covariance matrix (CSCM). Both representations were processed using the computer code PUFF-IV. This paper describes the procedures used to generate the RPCM with SAMMY.

  10. Isolation and Puification of Uranium Isotopes for Measurement by Mass-Spectrometry (233, 234, 235, 236, 238U) and Alpha Spectrometry (232U)

    SciTech Connect

    Marinelli, R; Hamilton, T; Brown, T; Marchetti, A; Williams, R; Tumey, S

    2006-05-30

    This report describes a standardized methodology used by researchers from the Center for Accelerator Mass Spectrometry (CAMS) (Energy and Environment Directorate) and the Environmental Radiochemistry Group (Chemistry and Materials Science Directorate) at the Lawrence Livermore National Laboratory (LLNL) for the full isotopic analysis of uranium from solution. The methodology has largely been developed for use in characterizing the uranium composition of selected nuclear materials but may also be applicable to environmental studies and assessments of public, military or occupational exposures to uranium using in-vitro bioassay monitoring techniques. Uranium isotope concentrations and isotopic ratios are measured using a combination of Multi Collector Inductively Coupled Plasma Mass Spectrometry (MC ICP-MS), Accelerator Mass Spectrometry (AMS) and Alpha Spectrometry.

  11. Dynamics of a Plasmacytic Reaction when Tetanus Antitoxin is Introduced by Aerosol and Subcutaneously (Dinamika Plazmotsitarnoi Reaktsii pri Vvedenii Stolbnyanogo Anatoksina Aerozolnym i Podkozhnym Metodom)

    DTIC Science & Technology

    typhoid fever antigen. Results are compared with those of the fever antigens alone. Comparisons are made between reactions of local lymph nodes and those remote from the place of antitoxin introduction.

  12. The Potential Role of the Thorium Fuel Cycle in Reducing the Radiotoxicity of Long-Lived Waste - 13477

    SciTech Connect

    Hesketh, Kevin; Thomas, Mike

    2013-07-01

    The thorium (or more accurately the Th-232/U-233) fuel cycle is attracting growing interest world wide and one reason for this is the reduced radiotoxicity of long-lived waste, with the Th- 232/U-233 fuel cycle often being justified partly on the grounds of low radiotoxicity for long cooling times. This paper considers the evolution of heavy metal radiotoxicity in a Molten Salt Fast Reactor (MSFR) operating a closed Th-232/U-233 cycle during different operational phases. The paper shows that even in the MSFR core, the equilibrium radiotoxicity of the thorium fuel cycle is only reached after almost 100 years of operation. MSFR was chosen because it has many theoretical advantages that favour the Th-232/U-233 fuel cycle. Conventional solid fuel systems would be expected to behave similarly, but with even longer timescales and therefore the MSFR cycle can be used to define the limits of what is practically achievable. The results are used to argue the case that a fair approach to justifying the Th-232/U-233 breeder cycle should not quote the long term equilibrium radiotoxicity, but rather the somewhat less favourable radiotoxicity that could be achieved within the operational lifetime of the first generation of Th-232/U-233 breeder reactors. (authors)

  13. Theory of cluster radioactive decay and of cluster formation in nuclei

    NASA Astrophysics Data System (ADS)

    Malik, S. S.; Gupta, Raj K.

    1989-05-01

    A new model is proposed for the mechanism of cluster formation and then penetration of the confining nuclear interaction barrier in radioactive nuclei. The cluster formation is treated as a quantum-mechanical fragmentation process and the WKB penetrability is found analytically. Applications of the model are made to 14C decay of 222-224Ra and 24Ne decay of 232U. The branching ratio for 14C decay of 232U is also calculated and is found to be incredibly small as compared to that for its 24Ne decay.

  14. Problems following hippocampal irradiation in interventional radiologists - doses and potential effects: a Monte Carlo simulation.

    PubMed

    Chumak, V; Morgun, A; Bakhanova, E; Loganovsky, K; Loganovska, T; Marazziti, D

    2015-12-01

    Metoiu doslidzhennia bulo vyvchyty zakonomirnosti formuvannia doz na gipokamp v umovakh roboty likaria inter ventsiynogo kardiologa u rentgen operatsiyniy metodom Monte Karlo, a takozh vstanovyty Ikhniy zv’iazok z efek tyvnoiu dozoiu (shcho vykorystovuiet'sia u radiatsiynomu zakhysti) ta pokazanniamy indyvidual'nykh dozymetriv, shchob otsinyty ymovirnist' dosiagnennia protiagom kar’iery rivnia dozy, pry iakomu mozhut' sposterigatysia taki radiatsiyni efekty, iak kognityvni porushennia ta inshi nervovo psykhichni rozlady.Materialy i metody: modeliuvannia metodom Monte Karlo doz oprominennia gipokampiv likaria za dopomogoiu gibrydnogo voksel'no matematychnogo fantoma dlia typovykh angiografichnykh proektsiy ta energetychnykh spektriv, vlastyvykh dlia protsedur interventsiynoI kardiologiI.Rezul'taty: pokazano, shcho oprominennia golovy ie syl'no neodnoridnym i zalezhyt' vid rentgenografichnoI pro ektsiI: vidminnist' doz oprominennia livogo ta pravogo gipokampa mozhe stanovyty do dvokh z polovynoiu raziv, za pevnykh umov doza u livomu gipokampi mozhe vdvichi perevyshchuvaty efektyvnu dozu, iaku otsiniuvaly za poshyrenym algorytmom podviynoI dozymetriI.Vysnovky: dozy na gipokamp protiagom stazhu profesiynogo oprominennia mozhut' siagaty velychyn, pry iakykh mo zhut' z’iavytysia kognityvni ta emotsiyno povedinkovi porushennia, tomu glyboke vyvchennia efektiv oprominennia mozku pratsivnykiv interventsiynoI radiologiI ie vkray neobkhidnym.

  15. Hybrid fusion-fission reactor with a thorium blanket: Its potential in the fuel cycle of nuclear reactors

    NASA Astrophysics Data System (ADS)

    Shmelev, A. N.; Kulikov, G. G.; Kurnaev, V. A.; Salahutdinov, G. H.; Kulikov, E. G.; Apse, V. A.

    2015-12-01

    Discussions are currently going on as to whether it is suitable to employ thorium in the nuclear fuel cycle. This work demonstrates that the 231Pa-232U-233U-Th composition to be produced in the thorium blanket of a hybrid thermonuclear reactor (HTR) as a fuel for light-water reactors opens up the possibility of achieving high, up to 30% of heavy metals (HM), or even ultrahigh fuel burnup. This is because the above fuel composition is able to stabilize its neutron-multiplying properties in the process of high fuel burnup. In addition, it allows the nuclear fuel cycle (NFC) to be better protected against unauthorized proliferation of fissile materials owing to an unprecedentedly large fraction of 232U (several percent!) in the uranium bred from the Th blanket, which will substantially hamper the use of fissile materials in a closed NFC for purposes other than power production.

  16. Radon Measurements at the Molten Salt Reactor Experiment (MSRE) Facility from August 1997 through April 1998

    SciTech Connect

    Coleman, R.L.

    1999-06-01

    Planned remediation at the Oak Ridge National Laboratory (ORNL) Molten Salt Reactor Experiment (MSRE) facility created the need to measure 220Rn and its progeny in air within work areas. Most of the original 233U fuel material is still present in the process system at the facility and will eventually be removed as decommissioning progresses. A hazard associated with the 233U material is the production of 220Rn from the 232U decay chain. Although 232U is in 233U material at a small mass fraction, it can equate to a significant activity level due to its short half-life. To illustrate the magnitudes of activity expected, consider the fuel material in the MSRE facility, which contains 232U at a mass concentration of 160 ppm. After a period of about 13 years, the 228Th activity would have equilibrated to about 3.5 Ci/kg of uranium. A kilogram of uranium would therefore be expected to produce 220Rn at a rate of 1.3E11 atoms/s, or 4.4E-2 Ci/s.

  17. Preparation of electrodeless discharge lamps for emission studies of uranium isotopes at trace level

    NASA Astrophysics Data System (ADS)

    Bhowmick, G. K.; Verma, R.; Verma, M. K.; Raman, V. A.; Joshi, A. R.; Deo, M. N.; Gantayet, L. M.; Tiwari, A. K.; Ramakumar, K. L.; Kumar, Navin

    2010-12-01

    A simplified method for preparation of electrodeless discharge lamp for uranium isotopes with specific concerns for 232U is described. Micro-gram quantities of solid uranium oxides and aqueous solution of uranium nitrate have been used as a starting material for in situ synthesis of uranium tetraiodide. High temperature iodination reaction is carried out in the presence of inert gas neon. By careful design, the preparation time and surface area of quartz reaction tubes have been reduced considerably. The latter decreases the level of contamination which has a direct bearing on the operational lifetime of the lamps. Incorporation of steps to purify the product from an unwanted material improved the stability of the lamps. The procedure provides a safe and convenient way of handling 232U in particular but can be extended in general to any actinides having radioactivity similar to that of freshly separated 232U. Characteristic emission of uranium isotopes have been recorded by Fourier Transform Spectrometer to show the satisfactory operation of the lamps as well as their usage for studying emission spectra of the specific isotope.

  18. Radioactive dating of the elements

    NASA Technical Reports Server (NTRS)

    Cowan, John J.; Thielemann, Friedrich-Karl; Truran, James W.

    1991-01-01

    The extent to which an accurate determination of the age of the Galaxy, and thus a lower bound on the age of the universe, can be obtained from radioactive dating is discussed. Emphasis is given to the use of the long-lived radioactive nuclei Re-187, Th-232, U-238, and U-235. The nature of the production sites of these and other potential Galactic chronometers is examined along with their production ratios. Age determinations from models of nucleocosmochronology are reviewed and compared with age determination from stellar sources and age constraints form cosmological considerations.

  19. 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)

  20. Evolution of isotopic composition of reprocessed uranium during the multiple recycling in light water reactors with natural uranium feed

    SciTech Connect

    Smirnov, A. Yu. Sulaberidze, G. A.; Alekseev, P. N.; Dudnikov, A. A.; Nevinitsa, V. A. Proselkov, V. N.; Chibinyaev, A. V.

    2012-12-15

    A complex approach based on the consistent modeling of neutron-physics processes and processes of cascade separation of isotopes is applied for analyzing physical problems of the multiple usage of reprocessed uranium in the fuel cycle of light water reactors. A number of scenarios of multiple recycling of reprocessed uranium in light water reactors are considered. In the process, an excess absorption of neutrons by the {sup 236}U isotope is compensated by re-enrichment in the {sup 235}U isotope. Specific consumptions of natural uranium for re-enrichment of the reprocessed uranium depending on the content of the {sup 232}U isotope are obtained.

  1. Potential energy surfaces for cluster emitting nuclei

    SciTech Connect

    Poenaru, Dorin N.; Gherghescu, Radu A.; Greiner, Walter

    2006-01-15

    Potential energy surfaces are calculated by use of the most advanced asymmetric two-center shell model that allows us to obtain shell-and-pairing corrections that are added to the Yukawa-plus-exponential model deformation energy. Shell effects are of crucial importance for the experimental observation of spontaneous disintegration by heavy-ion emission. Results for {sup 222}Ra, {sup 232}U, {sup 236}Pu, and {sup 242}Cm illustrate the main ideas and show for the first time, for a cluster emitter, a potential barrier obtained by use of the macroscopic-microscopic method.

  2. Total and spontaneous fission half-lives of the uranium and plutonium nuclides

    SciTech Connect

    Holden, N.E.

    1984-01-01

    The total half-life and the half-life for spontaneous fission are evaluated for the various long-lived nuclides of interest. Recommended values are presented for /sup 232/U, /sup 233/U, /sup 234/U, /sup 235/U, /sup 236/U, /sup 238/U, /sup 236/Pu, /sup 238/Pu, /sup 239/Pu, /sup 240/Pu, /sup 241/Pu, /sup 242/Pu, and /sup 244/Pu. The uncertainties are provided at the 95% confidence limit for each of the recommended values.

  3. Radioactive dating of the elements

    NASA Technical Reports Server (NTRS)

    Cowan, John J.; Thielemann, Friedrich-Karl; Truran, James W.

    1991-01-01

    The extent to which an accurate determination of the age of the Galaxy, and thus a lower bound on the age of the universe, can be obtained from radioactive dating is discussed. Emphasis is given to the use of the long-lived radioactive nuclei Re-187, Th-232, U-238, and U-235. The nature of the production sites of these and other potential Galactic chronometers is examined along with their production ratios. Age determinations from models of nucleocosmochronology are reviewed and compared with age determination from stellar sources and age constraints form cosmological considerations.

  4. The Th and U abundances in chondritic meteorites

    NASA Technical Reports Server (NTRS)

    Chen, J. H.; Wasserburg, G. J.; Papanastassiou, D. A.

    1993-01-01

    We present new analyses of Th-232/U-238 in CI and CM meteorites. The relative abundance of these nuclides is important in estimates of the age of r-process elements. The cosmochronology based upon the Th-232/U-238 ratio (kappa) depends on the precise determinations of these two different elements in meteorites and on the production ratios. Both parameters are subject to substantial errors. Recent recalculations of this chronology have used selected values from compilations but do not adequately address the errors in terms of a reliable data base. Morgan and Lovering provided extensive neutron activation analyses for ordinary chondrites which yield an average kappa of 3.6 +/- 0.4. Their work on carbonaceous chondrites showed a wide range in kappa from 2 to 6. More recent investigations by isotopic dilution have established the following: (1) highly variable kappa from 2.7 to 11 in Allende Ca-Al-rich inclusions and a value of 3.6 in the Orgueil CI1 chondrite; (2) a range from 2.71 to 6.63 for 7 L-type chondrites and a range from 2.7 to 4.4 for 6 L, H, and LL chondrites. A further investigation of this subject matter is presented.

  5. Expression of Cyclin d1 protein and CCND1 та PNKP genes in peripheral blood mononuclear cells in clean up worker of Chornobyl accident with different state of immune system.

    PubMed

    Bazyka, D A; Kubashko, A V; Ilyenko, I M; Belyaev, O A; Pleskach, O J

    2015-12-01

    Meta. Doslidyty zminy rivniv Cyclin D1+ klityn ta asotsiyovanykh geniv CCND1 ta PNKP u mononuklearakh peryfe rychnoI krovi v uchasnykiv likvidatsiI naslidkiv avariI (ULNA) na ChAES z riznym imunnym statusom v zalezhnosti vid dozy oprominennia.Materialy i metody. Proanalizovano vidnosnyy riven' Cyclin D1+ klityn u mononuklearakh peryferychnoI krovi 39 ULNA na ChAES, cholovikiv, oprominenykh u dozi u diapazoni (0,01–2,00) Gr. Imunologichnyy status obstezhenykh vyz nachavsia za rivnem CD3/19, CD4/8, CD3/HLA DR, SD3/16/56 metodom protochnoI tsytofluorymetriI ta za vmistom Ig klasiv A,M,G metodom imunofermentnogo analizu u krovi. Ekspresiia geniv CCND1 ta PNKP, iaki pov’iazani z Syclin D1, provodylos' za metodom polimeraznoI lantsiugovoI reaktsiI u real'nomu chasi. Porivniannia rezul'tativ zdiysniuva los' iz vidpovidnymy danymy, otrymanymy vid 18 zdorovykh cholovikiv, iaki ne maly kontaktu z ionizuiuchym vyp rominiuvanniam vyshche pryrodn'ogo fonu.Rezul'taty. Pokazano, shcho vidsotok Suclin D1+ klityn zbil'shuiet'sia za normu v osib, oprominenykh u dozi > 0,1 Gr, ta koreliuie z dozoiu oprominennia (rs = 0,417, p = 0,048). Vidkhylennia rivnia Cyclin D1+ klityn za mezhi kontrol'nykh zna chen' pov’iazuiet'sia zi zminamy v klitynniy ta gumoral'niy lankakh imunitetu. Zmenshennia vidsotku Cyclin D1+ klityn za mezhi kontrol'nykh znachen' v ULNA na ChAES iz dozoiu < 0,35 Gr suprovodzhuiet'sia znyzhenniam rivniv CD3+ ta pidvy shchenniam CD3 16+56+ limfotsytiv; u osib, oprominenykh u dozi > 0,35 Gr, zbil'shennia vidsotku Cyclin D1+ klityn asotsiiuiet'sia zi znyzhenniam CD3+ ta tendentsiieiu shchodo znyzhennia CD3+16+56+ limfotsytiv u poiednanni zi zbil'shen niam rivnia IgG. Zbil'shennia rivniv CD4+, CD19+, Ireg. ta IgG suprovodzhuiet'sia poiavoiu koreliatsiynykh zv’iazkiv mizh Cyclin D1+ ta CD3 16+56+ klitynamy (rs = 0,872, p = 0,049), Cyclin D1+ ta CD8+ i IgG (rs = 0,683, p = 0,042; rs = 0,809, p = 0,014), Cyclin D1+ ta CD4+ (rs = 0,602, p = 0,029), Cyclin D1+ ta CD19+ i

  6. Expeditious method to determine uranium in the process control samples of chemical plant separating (233)U from thoria irradiated in power reactors.

    PubMed

    Kedari, C S; Kharwandikar, B K; Banerjee, K

    2016-11-01

    Analysis of U in the samples containing a significant proportion of (232)U and high concentration of Th is of great concern. Transmutation of Th in the nuclear power reactor produces a notable quantity of (232)U (half life 68.9 years) along with fissile isotope (233)U. The decay series of (232)U is initiated with (228)Th (half life 1.9 year) and it is followed by several short lived α emitting progenies, (224)Ra, (220)Rn, (216)Po, (212)Bi and (212)Po. Even at the smallest contamination of (228)Th in the sample, a very high pulse rate of α emission is obtained, which is to be counted for the radiometric determination of [U]. A commercially available anionic type of extractant Alamine®336 is used to obtain the selective extraction of U from other alpha active elements and fission products present in the sample. Experimental conditions of liquid-liquid extraction (LLE) are optimized for obtaining maximum decontamination and recovery of U in the organic phase. The effect of some interfering ionic impurities in the sample on the process of separation is investigated. Depending on the level of the concentration of U in the samples, spectrophotometry or radiometry methods are adopted for its determination after separation by LLE. Under optimized experimental conditions, i.e. 5.5M HCl in the aqueous phase and 0.27M Alamin®336 in the organic phase, the recovery of U is about 100%, the decontamination factor with respect to Th is >2000 and the extraction of fission products like (90)Sr, (144)Ce and (134,137)Cs is negligible. The detection limit for [U] using α radiometry is 10mg/L, even in presence of >100g/L of Th in the sample. Accuracy and precision for the determination of U is also assessed. Reproducibility of results is within 5%. This method shows very good agreement with the results obtained by mass spectrometry.

  7. Radiological Control of Water in Reactor Pond of MR Reactor in NRC 'Kurchatov Institute', During Dismantling Work - 13462

    SciTech Connect

    Stepanov, Alexey; Simirsky, Yury; Semin, Ilya; Volkovich, Anatoly; Ivanov, Oleg

    2013-07-01

    The analysis of the activity and radionuclide composition of water from the MR reactor pond for α,β,γ-ray radionuclides was made. To solve this problem we use a wide range of laboratory equipment: gamma spectrometric complex, beta spectrometric complex, vacuum alpha spectrometer, and spectrometric complex with liquid scintillator. The water from MR reactor pond contains: Cs-137 (2,6*10{sup 2} Bq/g), Co-60(1,8 Bq/g), Sr-90 (1,0*10{sup 2} Bq/g), H-3 (7,0*10{sup 3} Bq/g), and components of nuclear fuel (U-232,U-234,U-235,U-236,U-238). Therefore the cleaning water from radioactivity waste occurs to be quite a complicated radiochemical task. (authors)

  8. Special Analysis for the Disposal of the Idaho National Laboratory Unirradiated Light Water Breeder Reactor Rods and Pellets Waste Stream at the Area 5 Radioactive Waste Management Site, Nevada National Security Site, Nye County, Nevada

    SciTech Connect

    2014-08-31

    The purpose of this special analysis (SA) is to determine if the Idaho National Laboratory (INL) Unirradiated Light Water Breeder Reactor (LWBR) Rods and Pellets waste stream (INEL103597TR2, Revision 2) is suitable for disposal by shallow land burial (SLB) at the Area 5 Radioactive Waste Management Site (RWMS). The INL Unirradiated LWBR Rods and Pellets waste stream consists of 24 containers with unirradiated fabricated rods and pellets composed of uranium oxide (UO2) and thorium oxide (ThO2) fuel in zirconium cladding. The INL Unirradiated LWBR Rods and Pellets waste stream requires an SA because the 229Th, 230Th, 232U, 233U, and 234U activity concentrations exceed the Nevada National Security Site (NNSS) Waste Acceptance Criteria (WAC) Action Levels.

  9. Transient Response of Continuous Elastic Structures.

    DTIC Science & Technology

    1977-02-01

    structural member with linear hysteretic damping governed by the following equation of motion : 2 - Du(x ,t) — ~~ A~ (x)3~u(x~t) — f (x)e~~ t ( lOla ) - i—i...phase. Hence I (u,t) — 3u — i~2u(x , t) (102) which when substituted into Equation ( lOla ) yields Du(x , t) i~2A 1u + A232u — f (x)e~~ t (103) I This... ChicO of Nov.! OpIr.t1000 ‘3 9’ ~o.po.o 2e.rtn. Dept. 0 5 thC 9509’ Co...aodioI 00(1.., Cttd. r t90 Eoplo .ton 9 , . n a r c 3 710 . *4.h in

  10. Annual Report on the Activities and Publications of the DHS-DNDO-NTNFC-Sponsored Post-doctoral Fellow at Los Alamos National Laboratory

    SciTech Connect

    Coleman, Magen E.; Tandon, Lav

    2012-04-24

    This report is a summary update on the projects Magen Coleman is working on as a postdoctoral fellow funded by DHS. These research projects are designed to explore different radioanalytical facets of nuclear forensics, including destructive and non-destructive analysis, chronometry measurements and modeling, spectral analysis, and actinide separations. Method development and instrumental analysis are integral parts of these projects, along with strong radiochemical knowledge. The current projects discussed here include method development for {sup 232}U analysis, the assembly of a gamma mapping system, the testing of neutron bubble detectors for neutron spectrometry, and continued work on the chronometry of plutonium and uranium materials. This report documents the work that has been performed since April 2011.

  11. Determination of alpha-emitting uranium isotopes in soft tissues by solvent extraction and alpha-spectrometry.

    PubMed

    Singh, N P; Wrenn, M E

    1983-04-01

    A radiochemical procedure has been developed for the determination of alpha-emitting isotopes of uranium ((238)U, (235)U and (234)U) in soft tissues. Known amounts of sample are spiked with (232)U internal tracer and wet-ashed. Uranium is co-precipitated with iron hydroxide as carrier, and extracted into 20% trilaurylamine solution in xylene after dissolution of the precipitate in 10M hydrochloric acid. The uranium, after stripping into an aqueous phase, is electro-deposited onto a platinum disc and counted by alpha-spectrometry. The radiochemical recovery ranges from 60 to 85% for bovine liver samples. The average radiochemical recoveries for human tissues vary from 53 to 78%.

  12. Technical Competencies for the Safe Interim Storage and Management of 233U at U.S. Department of Energy Facilities

    SciTech Connect

    Campbell, D.O.; Krichinsky, A.M.; Laughlin, S.S.; Van Essen, D.C.; Yong, L.K.

    1999-02-17

    Uranium-233 (with concomitant {sup 232}U) is a man-made fissile isotope of uranium with unique nuclear characteristics which require high-integrity alpha containment biological shielding, and remote handling. The special handling considerations and the fact that much of the {sup 233}U processing and large-scale handling was performed over a decade ago underscore the importance of identifying the people within the DOE complex who are currently working with or have worked with {sup 233}U. The availability of these key personnel is important in ensuring safe interim storage, management and ultimate disposition of {sup 233}U at DOE facilities. Significant programs are ongoing at several DOE sites with actinides. The properties of these actinide materials require many of the same types of facilities and handling expertise as does {sup 233}U.

  13. Influence of uncertainties of isotopic composition of the reprocessed uranium on effectiveness of its enrichment in gas centrifuge cascades

    NASA Astrophysics Data System (ADS)

    Smirnov, A. Yu; Mustafin, A. R.; Nevinitsa, V. A.; Sulaberidze, G. A.; Dudnikov, A. A.; Gusev, V. E.

    2017-01-01

    The effect of the uncertainties of the isotopic composition of the reprocessed uranium on its enrichment process in gas centrifuge cascades while diluting it by adding low-enriched uranium (LEU) and waste uranium. It is shown that changing the content of 232U and 236U isotopes in the initial reprocessed uranium within 15% (rel.) can significantly change natural uranium consumption and separative work (up to 2-3%). However, even in case of increase of these parameters is possible to find the ratio of diluents, where the cascade with three feed flows (depleted uranium, LEU and reprocessed uranium) will be more effective than ordinary separation cascade with one feed point for producing LEU from natural uranium.

  14. Nuclear Data Sheets for A = 232

    SciTech Connect

    Browne, E.

    2006-10-15

    The evaluator presents in this publication spectroscopic data and level schemes from radioactive decay and nuclear reactions for all nuclei with mass number A = 232. Highlights from this evaluation include the discovery of a new isotope of francium, {sup 232}Fr, and the study of its {beta} {sup -} decay to levels in {sup 232}Ra (2004Pe17,1990Me13). Also, it includes the first observation of spontaneous fission in {sup 232}Th and {sup 232}U, as well as the measurement of their respective partial half-lives of 1.2 (4) x 10{sup 21}y (1995Bo18) and 2.6 (5) x 10{sup 15}y (2000Bo46) for this type of decay.

  15. Updated ENDL99 Cross Sections for U(n.y) and U(n,f)

    SciTech Connect

    Brown, D; Dietrich, F; Hill, T; McNabb, D

    2002-05-07

    In this note, we describe the first of two updates to the uranium isotopes in Livermore's Evaluated Neutron Data Library, ENDL99. Here, we concentrate on improving the (n, f) and (n, {gamma}) evaluations for a limited set of uranium isotopes. The first improvement consisted of creating an evaluation for {sup 232}U using a combination of fission and capture cross sections from the JENDL-3.2 database and the outgoing particle distributions from the exiting ENDL99 {sup 234}U evaluation. The second improvement consisted of updating existing (n, f) and (n, {gamma}) evaluations for uranium isotopes with A=233-238. These improvements are particularly apparent in the neutron resonance region as ENDL99 often contains gross averages over the resonances. We have propagated these updates into various Livermore application libraries.

  16. Hybrid fusion–fission reactor with a thorium blanket: Its potential in the fuel cycle of nuclear reactors

    SciTech Connect

    Shmelev, A. N. Kulikov, G. G. Kurnaev, V. A. Salahutdinov, G. H. Kulikov, E. G. Apse, V. A.

    2015-12-15

    Discussions are currently going on as to whether it is suitable to employ thorium in the nuclear fuel cycle. This work demonstrates that the {sup 231}Pa–{sup 232}U–{sup 233}U–Th composition to be produced in the thorium blanket of a hybrid thermonuclear reactor (HTR) as a fuel for light-water reactors opens up the possibility of achieving high, up to 30% of heavy metals (HM), or even ultrahigh fuel burnup. This is because the above fuel composition is able to stabilize its neutron-multiplying properties in the process of high fuel burnup. In addition, it allows the nuclear fuel cycle (NFC) to be better protected against unauthorized proliferation of fissile materials owing to an unprecedentedly large fraction of {sup 232}U (several percent!) in the uranium bred from the Th blanket, which will substantially hamper the use of fissile materials in a closed NFC for purposes other than power production.

  17. Detection of previous neutron irradiation and reprocessing of uranium materials for nuclear forensic purposes.

    PubMed

    Varga, Zsolt; Surányi, Gergely

    2009-04-01

    The paper describes novel analytical methods developed for the detection of previous neutron irradiation and reprocessing of illicit nuclear materials, which is an important characteristic of nuclear materials of unknown origin in nuclear forensics. Alpha spectrometry and inductively coupled plasma sector-field mass spectrometry (ICP-SFMS) using solution nebulization and direct, quasi-non-destructive laser ablation as sample introduction were applied for the measurement of trace-level (232)U, (236)U and plutonium isotopes deriving from previous neutron irradiation of uranium-containing nuclear materials. The measured radionuclides and isotope ratios give important information on the raw material used for fuel production and enable confirm the supposed provenance of illicit nuclear material.

  18. Analysis of HEU samples from the ULBA Metallurgical Plant

    SciTech Connect

    Gift, E.H.

    1995-05-01

    In early March 1994, eight highly enriched uranium (HEU) samples were collected from materials stored at the Ulba Metallurgical Plant in Oskamen (Ust Kamenogorsk), Kazakhstan. While at the plant site, portions of four samples were dissolved and analyzed by mass spectrograph at the Ulba analytical laboratory by Ulba analysts. Three of these mass spectrograph solutions and the eight HEU samples were subsequently delivered to the Y-12 Plant for complete chemical and isotopic analyses. Chemical forms of the eight samples were uranium metal chips, U0{sub 2} powder, uranium/beryllium oxide powder, and uranium/beryllium alloy rods. All were declared by the Ulba plant to have a uranium assay of {approximately}90 wt % {sup 235}U. The uranium/beryllium powder and alloy samples were also declared to range from about 8 to 28 wt % uranium. The chemical and uranium isotopic analyses done at the Y-12 Plant confirm the Ulba plant declarations. All samples appear to have been enriched using some reprocessed uranium, probably from recovery of uranium from plutonium production reactors. As a result, all samples contain some {sup 236}U and {sup 232}U and have small but measurable quantities of plutonium. This plutonium could be the result of either contamination carried over from the enrichment process or cross-contamination from weapons material. It is not the result of direct reactor exposure. Neither the {sup 232}U nor the plutonium concentrations are sufficiently high to provide a significant industrial health hazard. Both are well within established or proposed acceptance criteria for storage at Y-12. The trace metal analyses showed that, with the exception of beryllium, there are no trace metals in any of these HEU samples that pose a significant health hazard.

  19. The morphological changes of mucous membrane of stomach and duodenum of contractor organization personnel, which works in radiation hazard conditions at the object Shelter of Chornobyl NPP.

    PubMed

    Sushko, V O; Nezgovorova, G A; Degtjarova, L V; Kolosynska, O O; Gromadska, V M

    2015-12-01

    Meta doslidzhennia: vyznachennia morfologichnykh osoblyvostei urazhen' slyzovoi obolonky (SO) shlunka ta dvanadtsiatypaloi kyshky (DPK) u personalu, iakyi pratsiuie v radiatsiino nebezpechnykh umovakh na ob’iekti «Ukryttia» Chornobyl's'koi AES (OU) shliakhom endoskopichnogo monitoryngu iz vziattiam biopsiinogo materialu z gastroduodenal'noi zony na etapakh pervynnogo (vkhidnogo) VkhK ta spetsial'nogo medychnogo kontroliu (SpK).Materialy ta metody: provedeno kompleksne klinichne-endoskopichne ta morfologichnogo doslidzhennia z biopsiieiu SO shlunka ta DPK u 126 robitnykiv OU.Rezul'taty: U personalu pidriadnykh pidpryiemstv OU vstanovleni riznoskerovani patomorfologichni zmin SO pry VkhK ta zbil'shennia chastoty ikh vyiavlennia pry obstezhenni pid chas SpK, shcho zagalom vidpovidaly khronichnomu H.pylori-asotsiiovanogo pangastrytu z porushenniam mikrotsyrkuliatsii i trofiky, dysregeneratsiinymy zminamy epitelial'noi vystilky.Vysnovky: dlia personalu pidriadnykh organizatsii, iakyi pryimaie uchast' v radiatsiino-nebezpechnykh robotakh na OU ie kharakternym naiavnist' khronichnogo H.pylori-asotsiiovanogo pangastrytu z zrostanniam chastoty atrofichnykh zmin SO (nemetaplastychnogo chy metaplastychnogo typu) ta rozvytkom erozyvno-vyrazkovykh urazhen' gastroduodenal'noi zony.V robitnykiv, iaki maly poperednii vplyv ionizuiuchogo oprominennia vstanovleno bil'shu chastotu dysregeneratsiinykh (giperplazii / kyshkovoi metaplazii) zmin epiteliiu, shcho vidpovidno pidvyshchuie ryzyk neoplastychnykh transformatsii.Provedennia EGDFS (za neobkhidnosti z biopsiieiu SO) pry VkhK ta nastupnykh etapakh medychnogo kontroliu u personalu, iakyi vykonuie radiatsiino-nebezpechni roboty na OU ie vysokoinformatyvnym dokazovym i neobkhidnym metodom doslidzhennia dlia vyznachennia formy ta stupeniu patologichnykh zmin verkhnikh viddiliv shlunkovo-kyshkovogo traktu dlia poperedzhennia progresuvannia zakhvoriuvannia ta rozvytku uskladnen', zberezhennia zdorov’ia i pratsezdatnosti robitnykiv.

  20. Technical Review Report for the Justification for 233U Content Envelope Safety Analysis Report for Packaging Model 9975-85, Addendum 2

    SciTech Connect

    West, M

    2008-07-25

    This report documents the review of Addendum 2, Justification for {sup 233}U Content Envelope, Safety Analysis Report for Packaging, prepared by Savannah River Packaging Technology (SRPT) of Savannah River National Laboratory (SRNL),--the Submittal--at the request of the Department of Energy's (DOE) National Nuclear Security Agency's (NNSA) Albuquerque Operations Office, for the shipment of 233U-bearing material from Los Alamos National Laboratory (LANL), in support of the Technical Area 18 (TA-18) Materials Relocation Program. This Addendum supplements the Safety Analysis Report for Packaging (SARP), Revision 0, and Addendum 1 to Revision 0 of the 9975 SARP (called Revision 0 of the 9975 SARP in this Addendum). The {sup 233}U-bearing items are currently stored at TA-18, awaiting shipment in the Model 9975-85 Package as a new Content Envelope, C.9. Following acceptance of this Addendum by the DOE-Headquarters Certifying Official (EM-60), and subsequent revision to the current Certificate of Compliance (CoC), the new contents will be authorized for shipment in the Model 9975-85 Package. The new Content Configuration, C.9, along with the optional Shielded-Pig Convenience Container Configuration, will be incorporated into the next revision of the Model 9975-85 Package SARP. In addition to the {sup 233}U-bearing items stored at TA-18, kilogram quantities of {sup 233}U-bearing materials are stored at Oak Ridge National Laboratory (ORNL). About one quarter of the items is Highly Enriched Uranium (HEU) as U{sub 3}O{sub 8} with {sup 233}U and {sup 232}U. Highly Enriched Uranium implies a {sup 236}U enrichment of >93%. The remaining material located at ORNL is pure {sup 233}U (>90%) with varying amounts of {sup 232}U. The form of the material is U{sub 3}O{sub 8}, UO{sub 3}, UO{sub 2}, and U metal. Additional DOE Sites may also have {sup 233}U-bearing materials for shipment.

  1. Fission-suppressed fusion breeder on the thorium cycle and nonproliferation

    NASA Astrophysics Data System (ADS)

    Moir, R. W.

    2012-06-01

    Fusion reactors could be designed to breed fissile material while suppressing fissioning thereby enhancing safety. The produced fuel could be used to startup and makeup fuel for fission reactors. Each fusion reaction can produce typically 0.6 fissile atoms and release about 1.6 times the 14 MeV neutron's energy in the blanket in the fission-suppressed design. This production rate is 2660 kg/1000 MW of fusion power for a year. The revenues would be doubled from such a plant by selling fuel at a price of 60/g and electricity at 0.05/kWh for Q=Pfusion/Pinput=4. Fusion reactors could be designed to destroy fission wastes by transmutation and fissioning but this is not a natural use of fusion whereas it is a designed use of fission reactors. Fusion could supply makeup fuel to fission reactors that were dedicated to fissioning wastes with some of their neutrons. The design for safety and heat removal and other items is already accomplished with fission reactors. Whereas fusion reactors have geometry that compromises safety with a complex and thin wall separating the fusion zone from the blanket zone where wastes could be destroyed. Nonproliferation can be enhanced by mixing 233U with 238U. Also nonproliferation is enhanced in typical fission-suppressed designs by generating up to 0.05 232U atoms for each 233U atom produced from thorium, about twice the IAEA standards of "reduced protection" or "self protection." With 2.4% 232U, high explosive material is predicted to degrade owing to ionizing radiation after a little over 1/2 year and the heat rate is 77 W just after separation and climbs to over 600 W ten years later. The fissile material can be used to fuel most any fission reactor but is especially appropriate for molten salt reactors (MSR) also called liquid fluoride thorium reactors (LFTR) because of the molten fuel does not need hands on fabrication and handling.

  2. Fission-suppressed fusion breeder on the thorium cycle and nonproliferation

    SciTech Connect

    Moir, R. W.

    2012-06-19

    Fusion reactors could be designed to breed fissile material while suppressing fissioning thereby enhancing safety. The produced fuel could be used to startup and makeup fuel for fission reactors. Each fusion reaction can produce typically 0.6 fissile atoms and release about 1.6 times the 14 MeV neutron's energy in the blanket in the fission-suppressed design. This production rate is 2660 kg/1000 MW of fusion power for a year. The revenues would be doubled from such a plant by selling fuel at a price of 60/g and electricity at $0.05/kWh for Q=P{sub fusion}/P{sub input}=4. Fusion reactors could be designed to destroy fission wastes by transmutation and fissioning but this is not a natural use of fusion whereas it is a designed use of fission reactors. Fusion could supply makeup fuel to fission reactors that were dedicated to fissioning wastes with some of their neutrons. The design for safety and heat removal and other items is already accomplished with fission reactors. Whereas fusion reactors have geometry that compromises safety with a complex and thin wall separating the fusion zone from the blanket zone where wastes could be destroyed. Nonproliferation can be enhanced by mixing {sup 233}U with {sup 238}U. Also nonproliferation is enhanced in typical fission-suppressed designs by generating up to 0.05 {sup 232}U atoms for each {sup 233}U atom produced from thorium, about twice the IAEA standards of 'reduced protection' or 'self protection.' With 2.4%{sup 232}U, high explosive material is predicted to degrade owing to ionizing radiation after a little over 1/2 year and the heat rate is 77 W just after separation and climbs to over 600 W ten years later. The fissile material can be used to fuel most any fission reactor but is especially appropriate for molten salt reactors (MSR) also called liquid fluoride thorium reactors (LFTR) because of the molten fuel does not need hands on fabrication and handling.

  3. Third Minima in Thorium and Uranium Isotopes in a Self-Consistent Theory

    SciTech Connect

    McDonnell, J. D.

    2013-01-01

    Background: Well-developed third minima, corresponding to strongly elongated and reflection-asymmetric shapes associated with dimolecular configurations, have been predicted in some non-self-consistent models to impact fission pathways of thorium and uranium isotopes. These predictions have guided the interpretation of resonances seen experimentally. On the other hand, self-consistent calculations consistently predict very shallow potential-energy surfaces in the third minimum region.

    Purpose: We investigate the interpretation of third-minimum configurations in terms of dimolecular (cluster) states. We study the isentropic potential-energy surfaces of selected even-even thorium and uranium isotopes at several excitation energies. In order to understand the driving effects behind the presence of third minima, we study the interplay between pairing and shell effects.

    Methods: We use the finite-temperature superfluid nuclear density functional theory. We consider two Skyrme energy density functionals: a traditional functional SkM and a recent functional UNEDF1 optimized for fission studies.

    Results: We predict very shallow or no third minima in the potential-energy surfaces of 232Th and 232U. In the lighter Th and U isotopes with N = 136 and 138, the third minima are better developed. We show that the reflection-asymmetric configurations around the third minimum can be associated with dimolecular states involving the spherical doubly magic 132Sn and a lighter deformed Zr or Mo fragment. The potential-energy surfaces for 228,232Th and 232U at several excitation energies are presented. We also study isotopic chains to demonstrate the evolution of the depth of the third minimum with neutron number.

    Conclusions: We show that the neutron shell effect that governs the existence of the dimolecular states around the third minimum is consistent with the spherical-to-deformed shape transition in the Zr andMo isotopes around N = 58.We demonstrate that the depth of

  4. Third minima in thorium and uranium isotopes in a self-consistent theory

    NASA Astrophysics Data System (ADS)

    McDonnell, J. D.; Nazarewicz, W.; Sheikh, J. A.

    2013-05-01

    Background: Well-developed third minima, corresponding to strongly elongated and reflection-asymmetric shapes associated with dimolecular configurations, have been predicted in some non-self-consistent models to impact fission pathways of thorium and uranium isotopes. These predictions have guided the interpretation of resonances seen experimentally. On the other hand, self-consistent calculations consistently predict very shallow potential-energy surfaces in the third minimum region.Purpose: We investigate the interpretation of third-minimum configurations in terms of dimolecular (cluster) states. We study the isentropic potential-energy surfaces of selected even-even thorium and uranium isotopes at several excitation energies. In order to understand the driving effects behind the presence of third minima, we study the interplay between pairing and shell effects.Methods: We use the finite-temperature superfluid nuclear density functional theory. We consider two Skyrme energy density functionals: a traditional functional SkM* and a recent functional UNEDF1 optimized for fission studies.Results: We predict very shallow or no third minima in the potential-energy surfaces of 232Th and 232U. In the lighter Th and U isotopes with N=136 and 138, the third minima are better developed. We show that the reflection-asymmetric configurations around the third minimum can be associated with dimolecular states involving the spherical doubly magic 132Sn and a lighter deformed Zr or Mo fragment. The potential-energy surfaces for 228,232Th and 232U at several excitation energies are presented. We also study isotopic chains to demonstrate the evolution of the depth of the third minimum with neutron number.Conclusions: We show that the neutron shell effect that governs the existence of the dimolecular states around the third minimum is consistent with the spherical-to-deformed shape transition in the Zr and Mo isotopes around N=58. We demonstrate that the depth of the third minimum

  5. Tags to Track Illicit Uranium and Plutonium

    SciTech Connect

    Haire, M. Jonathan; Forsberg, Charles W.

    2007-07-01

    With the expansion of nuclear power, it is essential to avoid nuclear materials from falling into the hands of rogue nations, terrorists, and other opportunists. This paper examines the idea of detection and attribution tags for nuclear materials. For a detection tag, it is proposed to add small amounts [about one part per billion (ppb)] of {sup 232}U to enriched uranium to brighten its radioactive signature. Enriched uranium would then be as detectable as plutonium and thus increase the likelihood of intercepting illicit enriched uranium. The use of rare earth oxide elements is proposed as a new type of 'attribution' tag for uranium and thorium from mills, uranium and plutonium fuels, and other nuclear materials. Rare earth oxides are chosen because they are chemically compatible with the fuel cycle, can survive high-temperature processing operations in fuel fabrication, and can be chosen to have minimal neutronic impact within the nuclear reactor core. The mixture of rare earths and/or rare earth isotopes provides a unique 'bar code' for each tag. If illicit nuclear materials are recovered, the attribution tag can identify the source and lot of nuclear material, and thus help police reduce the possible number of suspects in the diversion of nuclear materials based on who had access. (authors)

  6. 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.

  7. Nuclear forensic analysis of uranium oxide powders interdicted in Victoria, Australia

    DOE PAGES

    Kristo, Michael Joseph; Keegan, Elizabeth; Colella, Michael; ...

    2015-04-13

    Nuclear forensic analysis was conducted on two uranium samples confiscated during a police investigation in Victoria, Australia. The first sample, designated NSR-F-270409-1, was a depleted uranium powder of moderate purity (~1000 μg/g total elemental impurities). The chemical form of the uranium was a compound similar to K2(UO2)3O4·4H2O. While aliquoting NSR-F-270409-1 for analysis, the body and head of a Tineid moth was discovered in the sample. The second sample, designated NSR-F-270409-2, was also a depleted uranium powder. It was of reasonably high purity (~380 μg/g total elemental impurities). The chemical form of the uranium was primarily UO3·2H2O, with minor phases ofmore » U3O8 and UO2. While aliquoting NSR-F-270409-2 for analysis, a metal staple of unknown origin was discovered in the sample. The presence of 236U and 232U in both samples indicates that the uranium feed stocks for these samples experienced a neutron flux at some point in their history. The reactor burn-up calculated from the isotopic composition of the uranium is consistent with that of spent fuel from natural uranium (NU) fueled Pu production. These nuclear forensic conclusions allow us to categorically exclude Australia as the origin of the material and greatly reduce the number of candidate sources.« less

  8. New empirical formula for (γ, n) reaction cross section near GDR peak for elements with Z ⩾ 60.

    NASA Astrophysics Data System (ADS)

    Makwana, Rajnikant; Mukherjee, S.; Wang, Jian-Song; Chen, Zhi-Qiang

    2017-04-01

    A new empirical formula has been developed that describes the (γ, n) nuclear reaction cross sections for isotopes with Z ⩾ 60. The results were supported by calculations using TALYS - 1.6 and EMPIRE - 3.2.2 nuclear modular codes. The energy region for incident photon energy has been selected near the giant dipole resonance (GDR) peak energy. The evaluated empirical data were compared with available data in the experimental data library EXFOR. The data produced using TALYS - 1.6 and EMPIRE - 3.2.2 are in good agreement with experimental data. We have tested and presented the reproducibility of the present new empirical formula. We observe the reproducibility of the new empirical formula near the GDR peak energy is in good agreement with the experimental data and shows a remarkable dependency on key nuclei properties: the neutron, proton and atomic number of the nuclei. The behavior of nuclei near the GDR peak energy and the dependency of the GDR peak on the isotopic nature are predicted. An effort has been made to explain the deformation of the GDR peak in (γ, n) nuclear reaction cross sections for some isotopes, which could not be reproduced with TALYS - 1.6 and EMPIRE - 3.2.2. The evaluated data have been presented for the isotopes 180W, 183W, 202Pb, 203Pb, 204Pb, 205Pb, 231Pa, 232U, 237U and 239Pu, for which there are no previous measurements.

  9. Parametric Studies for 233U Gamma Spectrometry

    SciTech Connect

    Scheffing, C.C.; Krichinsky, A.

    2004-01-01

    Quantification of special nuclear material is a necessary aspect to assuring material accountability and is often accomplished using non-destructive gamma spectrometry. For 233U, gamma rays are affected by matrix and packaging attenuation and by a strong Compton continuum from decay products of 232U (inherently found in 233U) that obscure 233U gamma photopeaks. This project, based on current work at the national repository for separated 233U located at Oak Ridge National Laboratory (ORNL), explores the effects of various parameters on the quantification of 233U– including material form and geometry. Using an attenuation correction methodology for calculating the mass of 233U from NDA analysis, a bias of almost 75% less than the actual 233U mass was identified. The source of the bias needs to be understood at a more fundamental level for further use of this quantification method. Therefore, controlled experiments using well characterized packages of 233U were conducted at the repository and are presented in this paper.

  10. The Fission Programme at the CERN n_TOF Facility

    NASA Astrophysics Data System (ADS)

    Tsinganis, A.; Barbagallo, M.; Berthoumieux, E.; Calviani, M.; Chiaveri, E.; Colonna, N.; Diakaki, M.; Duran, I.; Guerrero, C.; Gunsing, F.; Leal-Cidoncha, E.; Leong, L.-S.; Paradela, C.; Tarrio, D.; Tassan-Got, L.; Vlastou, R.

    Since 2001, the scientific programme of the CERN n_TOF facility has focused mainly on the study of radiative neutron capture reactions, which are of great interest to nuclear astrophysics and on neutron-induced fission reactions, which are of relevance for nuclear technology, as well as essential for the development of theoretical models of fission. In particular, taking advantage of the high instantaneous neutron flux and high energy resolution of the facility, as well as of high-performance detection and acquisition systems, accurate new measurements on several long-lived major and minor actinides, from 232Th to 245Cm, have been performed so far. Data on these isotopes are needed in order to improve the safety and efficiency of conventional reactors, as well as to develop new systems for nuclear energy production and treatment of nuclear waste, such as Generation IV reactors, Accelerator Driven Systems and reactors based on innovative fuel cycles. A review of the most important results on fission cross-sections and fragment properties obtained at n_TOF for a variety of (radioactive) isotopes is presented along with the perspectives arising from the coming on line in the second half of 2014 of a new 19 m flight-path, which will allow n_TOF to expand its measurement capabilities to even more rare or short-lived isotopes, such as 230Th, 232U, 238,240Pu and 244Cm.

  11. Sorption of radioactive contaminants by sediment from the Kara Sea.

    PubMed

    Fuhrmann, M; Zhou, H; Neiheisel, J; Dyer, R

    2001-01-01

    The purpose of this study is to quantify some of the parameters needed to perform near-field modelling of sites in the Kara Sea that were impacted by the disposal of radioactive waste. The parameters of interest are: the distribution coefficients (Kd) for several important radionuclides, the mineralogy of the sediment, and the relationship of Kd to liquid-to-solid ratio. Sediment from the Kara Sea (location: 73 degrees 00'N, 58 degrees 00'E) was sampled from a depth of 287 m on August 23/24, 1992. Analysis of the material included mineralogy, grain size and total organic carbon (TOC). Uptake kinetics were determined for 85Sr, 137Cs, 241Am, 99Tc, 1251, 232U and 210Pb and distribution coefficients (Kd) were determined for these radionuclides using batch type experiments. Sorption isotherms, developed for 137Cs, 85Sr and 99Tc, were linear in each case. Increasing the liquid-to-solid ratio strongly increased uptake of 137Cs and moderately increased uptake of 99Tc. Analysis for anthropogenic radionuclides indicated the presence only of 239/240Pu in the sediment with the highest activity (at the top section of the core) being 0.420 Bq kg(-1). Other anthropogenic radionuclides were below detection limits.

  12. Fission foil measurements of neutron and proton fluences in the A0015 experiment

    NASA Technical Reports Server (NTRS)

    Frank, A. L.; Benton, E. V.; Armstrong, T. W.; Colborn, B. L.

    1995-01-01

    Results are given from sets of fission foil detectors (FFD's) (Ta-181, Bi-209, Th-232, U-238) which were included in the A0015 experiment to measure combined proton/neutron fluences. Use has been made of recent FFD high energy proton calibrations for improved accuracy of response. Comparisons of track density measurements have been made with the predictions of environmental modeling based on simple 1-D (slab) geometry. At 1 g/cm(exp 2) (trailing edge) the calculations were approximately 25 percent lower than measurements; at 13 g/cm(exp 2) (Earthside) calculations were more than a factor of 2 lower. A future 3-D modeling of the experiment is needed for a more meaningful comparison. Approximate mission proton doses and neutron dose equivalents were found. At Earthside (13 g/cm(exp 2) the dose was 171 rad and dose equivalent was 82 rem. At the trailing edge (1 g/cm(exp 2) dose was 315 rad and dose equivalent was 33 rem. The proton doses are less than expected from TLD doses by 16 percent and 37 percent, respectively. These differences can be explained by uncertainties in the proton and neutron spectra and in the method used to separate proton and neutron contributions to the measurements.

  13. Development of Impregnated Agglomerate Pelletization (IAP) process for fabrication of (Th,U)O 2 mixed oxide pellets

    NASA Astrophysics Data System (ADS)

    Khot, P. M.; Nehete, Y. G.; Fulzele, A. K.; Baghra, Chetan; Mishra, A. K.; Afzal, Mohd.; Panakkal, J. P.; Kamath, H. S.

    2012-01-01

    Impregnated Agglomerate Pelletization (IAP) technique has been developed at Advanced Fuel Fabrication Facility (AFFF), BARC, Tarapur, for manufacturing (Th, 233U)O 2 mixed oxide fuel pellets, which are remotely fabricated in hot cell or shielded glove box facilities to reduce man-rem problem associated with 232U daughter radionuclides. This technique is being investigated to fabricate the fuel for Indian Advanced Heavy Water Reactor (AHWR). In the IAP process, ThO 2 is converted to free flowing spheroids by powder extrusion route in an unshielded facility which are then coated with uranyl nitrate solution in a shielded facility. The dried coated agglomerate is finally compacted and then sintered in oxidizing/reducing atmosphere to obtain high density (Th,U)O 2 pellets. In this study, fabrication of (Th,U)O 2 mixed oxide pellets containing 3-5 wt.% UO 2 was carried out by IAP process. The pellets obtained were characterized using optical microscopy, XRD and alpha autoradiography. The results obtained were compared with the results for the pellets fabricated by other routes such as Coated Agglomerate Pelletization (CAP) and Powder Oxide Pelletization (POP) route.

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

    SciTech Connect

    Stoyer, M.A. . Nuclear Science Div. California Univ., Berkeley, CA . Dept. of Chemistry)

    1990-11-15

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

  15. Acute Pancreatitis Complicated with Diabetic Ketoacidosis in a Young Adult without Hypertriglyceridemia: A Case Report.

    PubMed

    Kim, Jung Hyun; Oh, Myung Jin

    2016-11-25

    Systemic complications related to acute pancreatitis include acute respiratory distress syndrome, multiple organ dysfunction syndrome, disseminated intravascular coagulation, hypocalcemia, hyperglycemia, and insulin dependent diabetes or diabetic ketoacidosis. In practice, the development of diabetic ketoacidosis induced by acute pancreatitis is rare and generally associated with hypertriglyceridemia. However, herein we report a case of a 34-year-old female without hypertriglyceridemia, who was diagnosed with acute pancreatitis complicated with diabetic ketoacidosis. The patient was admitted with complaints of febrile sensation, back pain, and abdominal pain around the epigastric area. Levels of serum amylase and lipase were elevated to 663 U/L and 3,232 U/L. Contrast-enhanced abdominal CT showed pancreatic swelling, peri-pancreatic fat infiltration and fluid collection. The patient was initially diagnosed with simple acute pancreatitis. Though the symptoms were rapidly relieved after initiation of treatment, severe hyperglycemia (575 mg/dL), severe metabolic acidosis (pH 6.9), and ketonuria developed at four days after hospitalization. However, serum triglyceride levels remained within the normal range (134 mg/dL). Finally, the patient was diagnosed with acute pancreatitis complicated with diabetic ketoacidosis unrelated to hypertriglyceridemia. She recovered through insulin and fluid therapy, and receives insulin therapy at the outpatient clinic.

  16. Sequential isotopic determination of plutonium, thorium, americium, strontium and uranium in environmental and bioassay samples.

    PubMed

    Wang, Jeng-Jong; Chen, Ing-Jane; Chiu, Jih-Hung

    2004-01-01

    A procedure has been developed to provide sequential analysis of 238Pu, 230Th, 241Am, 238U, and 90Sr in environmental and bioassay samples. Tracers and/or carriers (242Pu, 243Am, 232U, and stable strontium) are added into the sample as chemical yield monitors, and then, plutonium, thorium, strontium, americium, and uranium are sequentially separated and purified by Dowex ion-exchange resin, EiChroM Sr-resin, EiChroM TRU-resin, and Chelate-100 resin, respectively. The radioactivities of 90Sr and the actinides are measured using the liquid scintillation counter and alpha-particle spectrometer, respectively. Acidified water, glass-fiber air filter, soil, synthetic urine and synthetic feces samples of US National Institute of Standard and Technology Radiochemical Intercomparison Program(NRIP) were analyzed to verify this method. All the analytical results of 238Pu, 230Th, 90Sr, 241Am and 238U meet the traceability limit per ANSI N42.22, and when appropriate, evaluation of radiobioassay measurement bias and precision per ANSI N13.30.

  17. Heating and melting of small icy satellites by the decay of Al-26

    NASA Technical Reports Server (NTRS)

    Prialnik, Dina; Bar-Nun, Akiva

    1990-01-01

    The effect of radiogenic heating due to Al-26 on the thermal evolution of small icy satellites is studied. The object is to find the extent of internal melting as a function of the satellite radius and of the initial Al-26 abundance. The implicit assumption, based on observations of young stars, is that planet and satellite accretion occurred on a time scale of about 10 to the 6th yr (comparable with the lifetime of Al-26. The icy satellites are modeled as spheres of initially amorphous ice, with chondritic abundances of K-40, Th-232, U-235, and U-238, corresponding to an ice/dust mass ratio of 1. Evolutionary calculations are carried out, spanning 4.5 x 10 to the 9th yr, for different combinations of the two free parameters. Heat transfer by subsolidus convection is neglected for these small satellites. The main conclusion is that the initial Al-26 abundance capable of melting icy bodies of satellite size to a significant extent is more than 10 times lower than that prevailing in the interstellar medium (or that inferred from the Ca-Al rich inclusions of the Allende meteorite, about 7 x 10 to the -7th by mass).

  18. A method for determining the oxidation state of uranium in natural waters

    NASA Astrophysics Data System (ADS)

    Anderson, Robert F.

    1984-06-01

    Uranium exhibits radically different geochemical properties in its two oxidation states. Hexavalent uranium is quite soluble, especially when complexed by carbonate ions in alkaline solutions. Tetravalent uranium, by contrast, is very insoluble, and it would be expected to be rapidly removed from natural waters either by precipitation of a mineral phase such as UO 2(s) or by adsorption to solid surfaces. It is important to know the oxidation state in which uranium will occur under specified conditions of Eh and pH as this relates both to processes forming economically valuable uranium deposits and to the mobility of uranium released to the environment during various stages of the nuclear fuel cycle. In this work, yield monitors in each oxidation state [ 232U(IV)], 236U(VI)] are added to water samples, and uranium oxidation states are separated by a NdF 3 coprecipitation in which only the U(IV) is carried. The precipitate is removed by filtration. Subsequently, TiCl 3 is added to reduce U(IV) and the NdF 3 coprecipitation is repeated. A similar method is widely used for separating oxidation states of plutonium. Results from a meromictic lake (Fayetteville Green Lake, Syracuse, New York, USA) and from an anoxic marine basin (Cariaco Trench, Venezuela) where total H 2S concentrations in the bottom waters reach 1 mM 1 -1 and 50 μM 1 -1 respectively show that in both cases the dissolved uranium is present in its oxidized form.

  19. Laboratory column experiments for radionuclide adsorption studies of the Culebra dolomite member of the Rustler Formation

    SciTech Connect

    Lucero, D.A.; Heath, C.E.; Brown, G.O.

    1998-04-01

    Radionuclide transport experiments were carried out using intact cores obtained from the Culebra member of the Rustler Formation inside the Waste Isolation Pilot Plant, Air Intake Shaft. Twenty-seven separate tests are reported here and include experiments with {sup 3}H, {sup 22}Na, {sup 241}Am, {sup 239}Np, {sup 228}Th, {sup 232}U and {sup 241}Pu, and two brine types, AIS and ERDA 6. The {sup 3}H was bound as water and provides a measure of advection, dispersion, and water self-diffusion. The other tracers were injected as dissolved ions at concentrations below solubility limits, except for americium. The objective of the intact rock column flow experiments is to demonstrate and quantify transport retardation coefficients, (R) for the actinides Pu, Am, U, Th and Np, in intact core samples of the Culebra Dolomite. The measured R values are used to estimate partition coefficients, (kd) for the solute species. Those kd values may be compared to values obtained from empirical and mechanistic adsorption batch experiments, to provide predictions of actinide retardation in the Culebra. Three parameters that may influence actinide R values were varied in the experiments; core, brine and flow rate. Testing five separate core samples from four different core borings provided an indication of sample variability. While most testing was performed with Culebra brine, limited tests were carried out with a Salado brine to evaluate the effect of intrusion of those lower waters. Varying flow rate provided an indication of rate dependent solute interactions such as sorption kinetics.

  20. Heating and melting of small icy satellites by the decay of Al-26

    NASA Technical Reports Server (NTRS)

    Prialnik, Dina; Bar-Nun, Akiva

    1990-01-01

    The effect of radiogenic heating due to Al-26 on the thermal evolution of small icy satellites is studied. The object is to find the extent of internal melting as a function of the satellite radius and of the initial Al-26 abundance. The implicit assumption, based on observations of young stars, is that planet and satellite accretion occurred on a time scale of about 10 to the 6th yr (comparable with the lifetime of Al-26. The icy satellites are modeled as spheres of initially amorphous ice, with chondritic abundances of K-40, Th-232, U-235, and U-238, corresponding to an ice/dust mass ratio of 1. Evolutionary calculations are carried out, spanning 4.5 x 10 to the 9th yr, for different combinations of the two free parameters. Heat transfer by subsolidus convection is neglected for these small satellites. The main conclusion is that the initial Al-26 abundance capable of melting icy bodies of satellite size to a significant extent is more than 10 times lower than that prevailing in the interstellar medium (or that inferred from the Ca-Al rich inclusions of the Allende meteorite, about 7 x 10 to the -7th by mass).

  1. Heating and melting of small icy satellites by the decay of Al-26

    NASA Astrophysics Data System (ADS)

    Prialnik, Dina; Bar-Nun, Akiva

    1990-05-01

    The effect of radiogenic heating due to Al-26 on the thermal evolution of small icy satellites is studied. The object is to find the extent of internal melting as a function of the satellite radius and of the initial Al-26 abundance. The implicit assumption, based on observations of young stars, is that planet and satellite accretion occurred on a time scale of about 10 to the 6th yr (comparable with the lifetime of Al-26. The icy satellites are modeled as spheres of initially amorphous ice, with chondritic abundances of K-40, Th-232, U-235, and U-238, corresponding to an ice/dust mass ratio of 1. Evolutionary calculations are carried out, spanning 4.5 x 10 to the 9th yr, for different combinations of the two free parameters. Heat transfer by subsolidus convection is neglected for these small satellites. The main conclusion is that the initial Al-26 abundance capable of melting icy bodies of satellite size to a significant extent is more than 10 times lower than that prevailing in the interstellar medium (or that inferred from the Ca-Al rich inclusions of the Allende meteorite, about 7 x 10 to the -7th by mass).

  2. Heating and melting of small icy satellites by the decay of Al-26

    SciTech Connect

    Prialnik, D.; Bar-Nun, A. )

    1990-05-01

    The effect of radiogenic heating due to Al-26 on the thermal evolution of small icy satellites is studied. The object is to find the extent of internal melting as a function of the satellite radius and of the initial Al-26 abundance. The implicit assumption, based on observations of young stars, is that planet and satellite accretion occurred on a time scale of about 10 to the 6th yr (comparable with the lifetime of Al-26). The icy satellites are modeled as spheres of initially amorphous ice, with chondritic abundances of K-40, Th-232, U-235, and U-238, corresponding to an ice/dust mass ratio of 1. Evolutionary calculations are carried out, spanning 4.5 x 10 to the 9th yr, for different combinations of the two free parameters. Heat transfer by subsolidus convection is neglected for these small satellites. The main conclusion is that the initial Al-26 abundance capable of melting icy bodies of satellite size to a significant extent is more than 10 times lower than that prevailing in the interstellar medium (or that inferred from the Ca-Al rich inclusions of the Allende meteorite, about 7 x 10 to the -7th by mass). 34 refs.

  3. Chornobyl and reproductive health of a female rural population (an epidemiological study).

    PubMed

    Kundiev, Y I; Chernyuk, V I; Karakashyan, A N; Martynovskaya, T Y

    2013-01-01

    Cel'. Izuchit' sochetannoe dejstvie radiacionnogo i himicheskogo faktorov na reproduktivnoe zdorov'e sel'skih zhenshhin, prozhivajushhih i rabotajushhih na zagrjaznennyh posle avarii na ChAJeS territorijah. Material i metody. Proveden sociologicheskij opros i ginekologicheskij osmotr 1874 zhenshhin, izucheny 29 520 istorij rodov, 19 502 istorij novorozhdennyh, 1694 istorij boleznej zhenshhin so spontannymi abortami, a takzhe sostojanie menstrual'noj funkcii u 480 devochek-podrostkov, prozhivajushhih na radioaktivno zagrjaznennyh territorijah. Radioaktivnoe zagrjaznenie obsledovannyh territorij, a takzhe summarnuju jeffektivnuju dozu obluchenija ocenivali po rezul'tatam obshhedozimetricheskoj pasportizacii naselennyh punktov Ukrainy. Faktory proizvodstvennoj sredy (shum, mikroklimat, pyl', bakterial'naja obsemenennost' vozduha, tjazhest' i naprjazhennost' truda) izuchali obshheprinjatymi gigienicheskimi metodami i ocenivali po kriterijam „Gigienicheskoj klassifikacii truda…” #4137-86. Ostatochnoe kolichestvo hlororganicheskih pesticidov, ih izomerov i produktov transformacii v biosredah (krov', grudnoe moloko, pupovinnaja krov') opredeljali metodom gazozhidkostnoj hromatografii s detektorom po zahvatu jelektronov na priborah „Kristalljuks 4000” i modeli M-3700. Pri matematicheskoj obrabotke dannyh ispol'zovalis' korreljacionnyj, regressionnyj, diskriminantnyj analizy. Rezul'taty. Dokazano, chto posle avarii na ChAJeS reproduktivnoe zdorov'e sel'skih zhenshhin znachitel'no uhudshilos', naibolee vyrazhennye narushenija nabljudajutsja u molodyh zhenshhin v vozraste do 30 let. Pokazano, chto uhudshenie zdorov'ja javljaetsja rezul'tatom kompleksnogo vozdejstvija faktorov radiacionnoj i neradiacionnoj prirody, harakternyh dlja territorij prozhivanija, professional'noj dejatel'nosti, uslovij byta. V chastnosti, vozdejstvie pesticidov na fone radioaktivnogo zagrjaznenija javljaetsja dopolnitel'nym faktorom riska narushenij reproduktivnogo zdorov'ja zhenshhin. Po

  4. A Gamma Radiolysis Study of UO{sub 2}F{sub 2} 0.4H{sub 2}O Using Spent Nuclear Fuel Elements from the High Flux Isotope Reactor

    SciTech Connect

    Icenhour, A.S.

    2002-01-24

    The development of a standard for the safe, long-term storage of {sup 233}U-containing materials resulted in the identification of several needed experimental studies. These studies were largely related to the potential for the generation of unacceptable pressures or the formation of deleterious products during storage of uranium oxides. The primary concern was that these conditions could occur as a result of the radiolysis of residual impurities--specifically fluorides and water-by the high radiation fields associated with {sup 233}U/{sup 232}U-containing materials. This report documents the results from a gamma radiolysis experiment in which UO{sub 2}F{sub 2} {center_dot} 0.4H{sub 2}O was loaded in helium. This experiment was performed using spent nuclear fuel elements from the High Flux Isotope Reactor as the gamma source and was a follow-on to experiments conducted previously. It was found that upon gamma irradiation, the UO{sub 2}F{sub 2} {center_dot} 0.4H{sub 2}O released 0{sub 2} with an initial G(O{sub 2}) = 0.01 molecule O{sub 2}/100 eV and that some of the uranium was reduced from U(VI) to U(IV). The high total dose achieved in the SNF elements was sufficient to reach a damage limit for the UO{sub 2}F{sub 2} {center_dot} 0.4H{sub 2}O. This damage limit, measured in terms of the amount of the U(IV) produced, was found to be about 9 wt%.

  5. 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.

  6. Analysis on fuel breeding capability of FBR core region based on minor actinide recycling doping

    NASA Astrophysics Data System (ADS)

    Permana, Sidik; Novitrian, Waris, Abdul; Ismail, Suzuki, Mitsutoshi; Saito, Masaki

    2014-09-01

    Nuclear fuel breeding based on the capability of fuel conversion capability can be achieved by convertion rasio of some fertile materials into fissile materials during nuclear reaction processes such as main fissile materials of U-233, U-235, Pu-239 and Pu-241 and for fertile materials of Th-232, U-238, and Pu-240 as well as Pu-238. Minor actinide (MA) loading option which consists of neptunium, americium and curium will gives some additional contribution from converted MA into plutonium such as conversion Np-237 into Pu-238 and it's produced Pu-238 converts to Pu-239 via neutron capture. Increasing composition of Pu-238 can be used to produce fissile material of Pu-239 as additional contribution. Trans-uranium (TRU) fuel (Mixed fuel loading of MOX (U-Pu) and MA composition) and mixed oxide (MOX) fuel compositions are analyzed for comparative analysis in order to show the effect of MA to the plutonium productions in core in term of reactor criticality condition and fuel breeding capability. In the present study, neptunium (Np) nuclide is used as a representative of MAin trans-uranium (TRU) fuel composition as Np-MOX fuel type. It was loaded into the core region gives significant contribution to reduce the excess reactivity in comparing to mixed oxide (MOX) fuel and in the same time it contributes to increase nuclear fuel breeding capability of the reactor. Neptunium fuel loding scheme in FBR core region gives significant production of Pu-238 as fertile material to absorp neutrons for reducing excess reactivity and additional contribution for fuel breeding.

  7. Analysis on fuel breeding capability of FBR core region based on minor actinide recycling doping

    SciTech Connect

    Permana, Sidik; Novitrian,; Waris, Abdul; Ismail; Suzuki, Mitsutoshi; Saito, Masaki

    2014-09-30

    Nuclear fuel breeding based on the capability of fuel conversion capability can be achieved by conversion ratio of some fertile materials into fissile materials during nuclear reaction processes such as main fissile materials of U-233, U-235, Pu-239 and Pu-241 and for fertile materials of Th-232, U-238, and Pu-240 as well as Pu-238. Minor actinide (MA) loading option which consists of neptunium, americium and curium will gives some additional contribution from converted MA into plutonium such as conversion Np-237 into Pu-238 and it's produced Pu-238 converts to Pu-239 via neutron capture. Increasing composition of Pu-238 can be used to produce fissile material of Pu-239 as additional contribution. Trans-uranium (TRU) fuel (Mixed fuel loading of MOX (U-Pu) and MA composition) and mixed oxide (MOX) fuel compositions are analyzed for comparative analysis in order to show the effect of MA to the plutonium productions in core in term of reactor criticality condition and fuel breeding capability. In the present study, neptunium (Np) nuclide is used as a representative of MAin trans-uranium (TRU) fuel composition as Np-MOX fuel type. It was loaded into the core region gives significant contribution to reduce the excess reactivity in comparing to mixed oxide (MOX) fuel and in the same time it contributes to increase nuclear fuel breeding capability of the reactor. Neptunium fuel loading scheme in FBR core region gives significant production of Pu-238 as fertile material to absorp neutrons for reducing excess reactivity and additional contribution for fuel breeding.

  8. The influence of the duration of the expulsive stage of parturition on the occurrence of postpartum oxidative stress in sows with uncomplicated, spontaneous farrowings.

    PubMed

    Szczubiał, Marek; Dąbrowski, Roman; Bochniarz, Mariola; Komar, Marcin

    2013-10-15

    The aim of the study was to determine the influence of the duration of the expulsive stage of parturition on the occurrence of postpartum oxidative stress in sows with uncomplicated, spontaneous farrowings. Twenty-five pregnant gilts were divided into three groups on the basis of duration of the expulsive stage of farrowing: (I) duration of the expulsive stage was below 3 hours; (II) duration of the expulsive stage ranged from 3 to 6 hours; (III) duration of the expulsive stage was longer than 6 hours. Blood samples were collected at 24 to 48 hours before and 24 hours after parturition. As indicators of alterations in the redox state, we quantified the enzymatic activity of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT), as well as the blood levels of glutathione (GSH), thiobarbituric acid reactive substances (TBARS), and sulfhydryl groups (SH groups). In group III, it was found that erythrocyte activity of CAT (63.89 ± 6.70 vs. 53.18 ± 2.32 U/g Hb), as well as plasma GSH concentration (0.088 ± 0.020 vs. 0.045 ± 0.024 mmol/g protein) and SH groups content (5.045 ± 1.256 vs. 3.383 ± 0.430 μmol/g protein) decreased significantly (P < 0.05) at 24 hours after parturition, compared with their values during the last 48 hours before parturition. The concentration of TBARS increased not significantly, although markedly at 24 hours postpartum in group III (0.124 ± 0.014 vs. 0.153 ± 0.031 μmol/g protein). The results indicate that uncomplicated, spontaneous parturition can lead to the occurrence of oxidative stress during the early postparturient period in sows, the intensity of which is related to the duration of the expulsive stage. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Identification of a Novel Di-D-Fructofuranose 1,2’:2,3’ Dianhydride (DFA III) Hydrolysis Enzyme from Arthrobacter aurescens SK8.001

    PubMed Central

    Yu, Shuhuai; Wang, Xiao; Zhang, Tao; Stressler, Timo; Fischer, Lutz; Jiang, Bo; Mu, Wanmeng

    2015-01-01

    Previously, a di-D-fructofuranose 1,2’:2,3’ dianhydride (DFA III)-producing strain, Arthrobacter aurescens SK8.001, was isolated from soil, and the gene cloning and characterization of the DFA III-forming enzyme was studied. In this study, a DFA III hydrolysis enzyme (DFA IIIase)-encoding gene was obtained from the same strain, and the DFA IIIase gene was cloned and expressed in Escherichia coli. The SDS-PAGE and gel filtration results indicated that the purified enzyme was a homotrimer holoenzyme of 145 kDa composed of subunits of 49 kDa. The enzyme displayed the highest catalytic activity for DFA III at pH 5.5 and 55°C, with specific activity of 232 U mg-1. Km and Vmax for DFA III were 30.7 ± 4.3 mM and 1.2 ± 0.1 mM min-1, respectively. Interestingly, DFA III-forming enzymes and DFA IIIases are highly homologous in amino acid sequence. The molecular modeling and docking of DFA IIIase were first studied, using DFA III-forming enzyme from Bacillus sp. snu-7 as a template. It was suggested that A. aurescens DFA IIIase shared a similar three-dimensional structure with the reported DFA III-forming enzyme from Bacillus sp. snu-7. Furthermore, their catalytic sites may occupy the same position on the proteins. Based on molecular docking analysis and site-directed mutagenesis, it was shown that D207 and E218 were two potential critical residues for the catalysis of A. aurescens DFA IIIase. PMID:26555784

  10. Systematic study of probable projectile-target combinations for the synthesis of the superheavy nucleus 302120

    NASA Astrophysics Data System (ADS)

    Santhosh, K. P.; Safoora, V.

    2016-08-01

    Probable projectile-target combinations for the synthesis of the superheavy element 302120 have been studied taking the Coulomb and proximity potential as the interaction barrier. The probabilities of the compound nucleus formation PCN for the projectile-target combinations found in the cold reaction valley of 302120 are estimated. At energies near and above the Coulomb barrier, we have calculated the capture, fusion, and evaporation residue cross sections for the reactions of all probable projectile-target combinations so as to predict the most promising projectile-target combinations for the synthesis of the superheavy element 302120 in heavy-ion fusion reactions. The calculated fusion and evaporation cross sections for the more asymmetric ("hotter") projectile-target combination is found to be higher than the less asymmetric ("colder") combination. It can be seen from the nature of the quasifission barrier height, mass asymmetry, the probability of compound nucleus formation, survival probability, and excitation energy, the systems 44Ar+258No , 46Ar+256No , 48Ca+254Fm , 50Ca+252Fm , 54Ti+248Cf , and 58Cr+244Cm in deep region I of the cold reaction valley and the systems 62Fe+240Pu , 64Fe+238Pu , 68Ni+234U , 70Ni+232U , 72Ni+230U , and 74Zn+228Th in the other cold valleys are identified as the better projectile-target combinations for the synthesis of 302120. Our predictions on the synthesis of 302120 superheavy nuclei using the combinations 54Cr+248Cm , 58Fe+244Pu , 64Ni+238U , and 50Ti+249Cf are compared with available experimental data and other theoretical predictions.

  11. ORNL production of the experimental alpha emitters bismuth-213 and actinium-225 for medical applications

    SciTech Connect

    Webb, O.F.; Krichinsky, A.M.; Yong, L.K.

    1998-09-01

    Due to their short range in tissue (50 to 80 {micro}m), alpha emitters are of considerable interest for certain radioimmunotherapy applications. These applications require the destruction of single cells or small clusters of cells. The radioisotope {sup 213}Bi, which is milked from {sup 225}Ac, is an alpha emitter that is currently being used in phase-1 human leukemia trials at the Memorial Sloan-Kettering Cancer Center. The most readily achievable route for producing {sup 225}Ac generators involves separating ingrown {sup 229}Th daughters from the {sup 233}U parent. Thorium-229 is then used as a parent generator for {sup 225}Ac. Thorium-229 is easier to handle than {sup 233}U, which is fissile and typically contains trace concentrations of {sup 232}U. Uranium-232 has a radioactive daughter, {sup 208}Tl, which emits a high-energy (2.6-MeV) photon when it decays. An alternative method for producing {sup 229}Th is through neutron irradiation of {sup 227}Ra. However, this method is less desirable due to the production of very high levels of {sup 228}Th. Thorium-229 accumulates in stored {sup 233}U oxides by natural decay. The current ORNL process for extracting {sup 229}Th from stored {sup 233}U oxides includes dissolution, strong-acid anion exchange, and calcination of the uranium. This ORNL process has provided high-purity {sup 225}Ac generators to medical researchers. Bismuth-213 has been extracted and used in initial human trials and already has demonstrated a potency and specificity for attacking cancerous cells.

  12. Waste Stream Generated and Waste Disposal Plans for Molten Salt Reactor Experiment at Oak Ridge National Laboratory

    SciTech Connect

    Haghighi, M. H.; Szozda, R. M.; Jugan, M. R.

    2002-02-26

    The Molten Salt Reactor Experiment (MSRE) site is located in Tennessee, on the U.S. Department of Energy (DOE) Oak Ridge Reservation (ORR), south of the Oak Ridge National Laboratory (ORNL) main plant across Haw Ridge in Melton Valley. The MSRE was run by ORNL to demonstrate the desirable features of the molten-salt concept in a practical reactor that could be operated safely and reliably. It introduced the idea of a homogeneous reactor using fuel salt media and graphite moderation for power and breeder reactors. The MSRE reactor and associated components are located in cells beneath the floor in the high-bay area of Building 7503 (Figure 1). The reactor was operated from June 1965 to December 1969. When the reactor was shut down, fuel salt was drained from the reactor circuit to two drain tanks. A ''clean'' salt was then circulated through the reactor as a decontamination measure and drained to a third drain tank. When operations ceased, the fuel and flush salts were allowed t o cool and solidify in the drain tanks. At shutdown, the MSRE facility complex was placed in a surveillance and maintenance program. As a result of the S&M program, it was discovered in 1994 that gaseous uranium (233U/232U) hexafluoride (UF6) had moved throughout the MSRE process systems. The UF6 was generated when radiolysis of the fluorine salts caused the individual constituents to dissociate to their component atoms, including free fluorine.Some of the free fluorine combined with uranium fluorides (UF4) in the salt to form UF6. UF6 is gaseous at slightly above ambient temperatures; thus, periodic heating of the fuel salts (which was intended to remedy the radiolysis problems) and simple diffusion had allowed the UF6 to move out of the salt and into the process systems of MSRE.

  13. Observation of novel radioactive decay by spontaneous emission of complex nuclei

    SciTech Connect

    Barwick, S.W.

    1986-01-01

    Two years of experimental investigation on the subject of spontaneous emission of intermediate-mass fragments is described in this manuscript. A short introduction on this subject and a historical review are presented in chapter 1. In chapter 2, the author describe the experimental methods which led to the observation of /sup 14/C emission in polycarbonate etched-track detectors from the isotopes /sup 222/Ra, /sup 223/Ra, /sup 224/Ra and /sup 226/Ra at the branching ratios with respect to ..cap alpha..-decay of (3.7 +/- 0.6) x 10/sup -10/, (6.1 +/- 1.0) x 10/sup -10/, (4.3 +/- 1.2) x 10/sup -10/ and (2.9 +/- 1.0) x 10/sup -11/ respectively. Branching ratio limits for heavy-ion emission from /sup 221/Fr, /sup 221/Ra and /sup 225/Ac were determined to be at < 5.0 x 10/sup -14/, < 1.2 x 10/sup -13/ and < 4.0 x 10/sup -13/ respectively for the 90% C.L. The emission of /sup 24/Ne from /sup 232/U at a branching ratio of (2.0 +/- 0.5) x 10/sup -12/ has been discovered using polyethylene terephthalate etched-track plastics. A confirmation of /sup 24/Ne and/or /sup 25/Ne emission from /sup 233/U at a branching ratio of (5.3 +/- 2.3) x 10/sup -13/ is also reported. In chapter 3, three models of intermediate-mass decay are discussed-the analytic superasymmetric fission model, the model by Shi and Swiatecki, and a model based on a square-well + Coulomb potential.

  14. Overexpression and characterization of a recombinant l-ribose isomerase from Actinotalea fermentans ATCC 43279.

    PubMed

    Tseng, Wen-Chi; Wu, Tai-Jeng; Chang, Ya-Ju; Cheng, Hung-Wen; Fang, Tsuei-Yun

    2017-10-10

    A putative l-ribose isomerase (EC 5.3.1.B3, l-RI) gene of Actinotalea fermentans ATCC 43279 was chemically synthesized, subcloned into pET-21b vector, and then overexpressed in Escherichia coli. After 0.5mM IPTG induction at 20°C for 20h, the recombinant l-RI was highly expressed with up to 50% of the total proteins. About 70% of the expressed l-RI appeared in the cell-free extract as a soluble form, and a high yield of active l-RI, 23,800U/L or 952U/g of wet cells, was achieved. The purified recombinant l-RI demonstrated its optimal activity at 45°C and pH 8 (in tricine-NaOH buffer). Metal ions are not required for l-RI activity, but Hg(2+) inhibits its activity completely. The enzyme has a half-life of 74min at 50°C and an equilibrium ratio of 30:70 between l-ribulose and l-ribose at 45°C. The Vmax, kcat, KM, and catalytic efficiency (kcat/KM) of the recombinant l-RI against l-ribose are 232U/mg, 6700min(-1), 31.3mM, and 214min(-1)mM(-1), respectively. The high expression yield of the active recombinant A. fermentansl-RI and its highest Vmax, kcat, and catalytic efficiency among the characterized recombinant l-RIs suggest that this recombinant enzyme shows a potential application to produce l-ribose in industry. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Sequential extraction procedure for determination of uranium, thorium, radium, lead and polonium radionuclides by alpha spectrometry in environmental samples

    NASA Astrophysics Data System (ADS)

    Oliveira, J. M.; Carvalho, F. P.

    2006-01-01

    A sequential extraction technique was developed and tested for common naturally-occurring radionuclides. This technique allows the extraction and purification of uranium, thorium, radium, lead, and polonium radionuclides from the same sample. Environmental materials such as water, soil, and biological samples can be analyzed for those radionuclides without matrix interferences in the quality of radioelement purification and in the radiochemical yield. The use of isotopic tracers (232U, 229Th, 224Ra, 209Po, and stable lead carrier) added to the sample in the beginning of the chemical procedure, enables an accurate control of the radiochemical yield for each radioelement. The ion extraction procedure, applied after either complete dissolution of the solid sample with mineral acids or co-precipitation of dissolved radionuclide with MnO2 for aqueous samples, includes the use of commercially available pre-packed columns from Eichrom® and ion exchange columns packed with Bio-Rad resins, in altogether three chromatography columns. All radioactive elements but one are purified and electroplated on stainless steel discs. Polonium is spontaneously plated on a silver disc. The discs are measured using high resolution silicon surface barrier detectors. 210Pb, a beta emitter, can be measured either through the beta emission of 210Bi, or stored for a few months and determined by alpha spectrometry through the in-growth of 210Po. This sequential extraction chromatography technique was tested and validated with the analysis of certified reference materials from the IAEA. Reproducibility was tested through repeated analysis of the same homogeneous material (water sample).

  16. 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.

  17. Development of an Alternative Release Limit for a Former Uranium and Thorium Processing Plant in Cushing Oklahoma

    SciTech Connect

    Thatcher, A.H.

    2007-07-01

    The purpose of this presentation will be to describe how, through dose modeling and analysis, a complex site was able to obtain an Alternative Release Limit (ARL) that adequately protected the environment, met regulatory approval, and saved money in the process. The Kerr-McGee Refinery Site in Cushing, OK supported an experimental facility that processed nuclear fuel materials from 1963 to 1966. Radiological contaminants at the site as a result of operations consist of natural thorium and isotopes of uranium (Th-228, Th-232, U-234, U-235 and U-238). Site contamination existed in both surface and sub-surface soils and within a shallow aquifer. After the soil was remediated to acceptable regulatory limits, however, the potential existed for residual groundwater contamination to result in exposure to individuals following site closure. Traditional exposure pathway analysis for the resident farmer seemed to indicate that this exposure was excessive. A closer look at the exposure pathways present in this rural location showed that groundwater contamination existed in a shallow aquifer insufficient to support significant irrigation activities and was of sufficiently poor water quality that it could not be used for drinking water. Through the determination of aquifer yield pumping tests, agreement from the Oklahoma Department of Environmental Quality, and sensitivity and uncertainty analysis using Monte Carlo techniques, it was shown that the average member of the critical population was adequately protected in the current site configuration without further remediation. This paper describes the analytical methods and models used to apply the general dose limit of 0.25 mSv yr{sup -1} (25 mrem yr{sup -1}) to the particulars of the Cushing Site, and demonstrates how these methods achieved a much higher ARL for total uranium in groundwater that was accepted by the regulators and achieved significant savings for the Licensee. (authors)

  18. Biochemical and nutritional markers and antioxidant activity in metabolic syndrome.

    PubMed

    Bernabé García, Juana; Zafrilla Rentero, Pilar; Mulero Cánovas, Juana; Gómez Jara, Purificación; Leal Hernández, Mariano; Abellán Alemán, José

    2014-01-01

    1) Nutritional assessment of the diet followed by patients with metabolic syndrome, and 2) biochemical analysis of the oxidation-reduction level in patients with metabolic syndrome. A cross-sectional study was conducted in patients with metabolic syndrome in Murcia. Fifty-three patients, 33 with and 20 without (control group) metabolic syndrome, were selected. The intervention consisted of completion of a recall survey and a test to nutritionally assess dietary intake. Anthropometric and laboratory variables, including those related to antioxidant activity, were also tested. Antioxidant activity was within normal limits in both groups (1.7 ± 0.2 mmol/L in the control group and 1.8 ± 0.1 mmol/L in the metabolic syndrome group) (NS). Superoxide dismutase levels were not significantly different between the groups. Mean glutathione reductase levels (U/L) were higher in the control group as compared to patients with metabolic syndrome (P<.05). As regards oxidative stress biomarkers, mean isoprostane levels were higher in the control group (4.9 ± 6.2 ng/mL) than in metabolic syndrome patients (3.5 ± 3.9 ng/mL) (P<.05). Oxidized LDL values tended to be higher in metabolic syndrome patients (96 ± 23.2U/L) as compared to the control group (86.2 ± 17.3 U/L), but differences were not significant. There is a trend to a poorer nutritional and biochemical profile in patients with metabolic syndrome, who also tend to have a greater degree of oxidative stress. Copyright © 2013 SEEN. Published by Elsevier Espana. All rights reserved.

  19. ALARA Controls and the Radiological Lessons Learned During the Uranium Fuel Removal Projects at the Molten Salt Reactor Experiment

    SciTech Connect

    Gilliam, B. J.; Chapman, J. A.; Jugan, M. R.

    2002-02-26

    The removal of uranium-233 (233 U) from the auxiliary charcoal bed (ACB) of the Molten Salt Reactor Experiment (MSRE), performed from January through May 2001, created both unique radiological challenges and widely-applicable lessons learned. In addition to the criticality concerns and alpha contamination, 233U has an associated intense gamma photon from the cocontaminant uranium-232 (232U) decaying to thallium-208 (208Tl). Therefore, rigorous contamination controls and significant shielding were implemented. Extensive, timed mock-up training was also imperative to minimize individual and collective personnel exposures. Back-up shielding and containment techniques (that had been previously developed for defense in depth) were used successfully to control significant, changed conditions. Additional controls were placed on tests and on recovery designs to assure a higher level of safety throughout the removal operations. This paper delineates the manner in which each difficulty was solved, while relating the relevance of the results and the methodology to other projects with high dose-rate, highly-contaminated ionizing radiation hazards. Because of the distinctive features of and current interest in molten salt technology, a brief overview is provided. Also presented is the detailed, practical application of radiological controls integrated into, rather than added after, each evolution of the project--thus demonstrating the broad-based benefits of radiological engineering and ALARA reviews. The resolution of the serious contamination-control problems caused by unexpected uranium hexafluoride (UF6) gaseous diffusion is also explicated. Several tables and figures document the preparations, equipment and operations. A comparison of the pre-job dose calculations for the various functions of the uranium deposit removal (UDR) and the post-job dose-rate data are included in the conclusion.

  20. Study of calculated and measured time dependent delayed neutron yields. [TX, for calculating delayed neutron yields; MATINV, for matrix inversion; in FORTRAN for LSI-II minicomputer

    SciTech Connect

    Waldo, R.W.

    1980-05-01

    Time-dependent delayed neutron emission is of interest in reactor design, reactor dynamics, and nuclear physics studies. The delayed neutrons from neutron-induced fission of /sup 232/U, /sup 237/Np, /sup 238/Pu, /sup 241/Am, /sup 242m/Am, /sup 245/Cm, and /sup 249/Cf were studied for the first time. The delayed neutron emission from /sup 232/Th, /sup 233/U, /sup 235/U, /sup 238/U, /sup 239/Pu, /sup 241/Pu, and /sup 242/Pu were measured as well. The data were used to develop an empirical expression for the total delayed neutron yield. The expression gives accurate results for a large variety of nuclides from /sup 232/Th to /sup 252/Cf. The data measuring the decay of delayed neutrons with time were used to derive another empirical expression predicting the delayed neutron emission with time. It was found that nuclides with similar mass-to-charge ratios have similar decay patterns. Thus the relative decay pattern of one nuclide can be established by any measured nuclide with a similar mass-to-charge ratio. A simple fission product yield model was developed and applied to delayed neutron precursors. It accurately predicts observed yield and decay characteristics. In conclusion, it is possible to not only estimate the total delayed neutron yield for a given nuclide but the time-dependent nature of the delayed neutrons as well. Reactors utilizing recycled fuel or burning actinides are likely to have inventories of fissioning nuclides that have not been studied until now. The delayed neutrons from these nuclides can now be incorporated so that their influence on the stability and control of reactors can be delineated. 8 figures, 39 tables.

  1. Supplemental Report on Nuclear Safeguards Considerations for the Pebble Bed Modular Reactor (PBMR)

    SciTech Connect

    Moses, David Lewis; Ehinger, Michael H

    2010-05-01

    Recent reports by Department of Energy National Laboratories have discussed safeguards considerations for the low enriched uranium (LEU) fueled Pebble Bed Modular Reactor (PBMR) and the need for bulk accountancy of the plutonium in used fuel. These reports fail to account effectively for the degree of plutonium dilution in the graphitized-carbon pebbles that is sufficient to meet the International Atomic Energy Agency's (IAEA's) 'provisional' guidelines for termination of safeguards on 'measured discards.' The thrust of this finding is not to terminate safeguards but to limit the need for specific accountancy of plutonium in stored used fuel. While the residual uranium in the used fuel may not be judged sufficiently diluted to meet the IAEA provisional guidelines for termination of safeguards, the estimated quantities of {sup 232}U and {sup 236}U in the used fuel at the target burn-up of {approx}91 GWD/MT exceed specification limits for reprocessed uranium (ASTM C787) and will require extensive blending with either natural uranium or uranium enrichment tails to dilute the {sup 236}U content to fall within specification thus making the PBMR used fuel less desirable for commercial reprocessing and reuse than that from light water reactors. Also the PBMR specific activity of reprocessed uranium isotopic mixture and its A{sub 2} values for effective dose limit if released in a dispersible form during a transportation accident are more limiting than the equivalent values for light water reactor spent fuel at 55 GWD/MT without accounting for the presence of the principal carry-over fission product ({sup 99}Tc) and any possible plutonium contamination that may be present from attempted covert reprocessing. Thus, the potentially recoverable uranium from PBMR used fuel carries reactivity penalties and radiological penalties likely greater than those for reprocessed uranium from light water reactors. These factors impact the economics of reprocessing, but a more significant

  2. Fe-Mn substance in ocean as reason of regulation radionuclide pollution

    NASA Astrophysics Data System (ADS)

    Asavin, Alex; Martynov, Konstantin; Konstantinova, Lia

    2013-04-01

    Distribution of radionuclide in marine sediments as yet little studied [Choppin & Wong 1998]. The work mainly focused on effects of nuclear test fallout. In the works are examined isotopes of Pu - 238; Th - 232; U -234;238; Pu - 239,240,241; Am - 241; Np - 237; Cm -244 [Holm 1995]. It has been shown that seems to accumulate radionuclides in marine sediments. In particular, the importance attached to carbonate complexes (corals, etc.). But questions about the possibility of re-mobilization of radionuclide, forms their concentration, their participation in global geochemical cycles in the ocean, remain open. We believe a major factor controlling the distribution of heavy metals is the formation of ocean ferromanganese crusts and nodules hydrogenic at the bottom of the ocean and seamounts. It is likely that the process of formation of Fe-manganese hydrogenic can play a major role in the control of radioactive contamination in the oceanic sediment. At least for the U number of works on the subject [Sherman et al. 2008]. The high sensitivity of the Fe-manganese crust is known to the isotopic composition of lead [Loranger & Zayed 1994, Collen et al 2011]. Recent work [Wilkins etal 2006, Renshaw etal 2009] show a large role; Fe (III)-and Mn (IV)-reducing organisms that anaerobic bacteria in oxidation and therefore changes in mobility systems U and Pu. So much interest is data for sorption of radionuclide on hydroxides Fe and Mn. Unfortunately we are not aware of works on the subject. We have therefore taken their own experimental studies on sorption of radionuclide on natural Fe-Mn crusts (sample from Magellan seamount Pacific ocean) [Martynov et al 2012]. The results showed high sorption ability of material crusts for fixation of radionuclides: U-233, Np-237, Pu-238, Am-241. For all radionuclide experiment absorption has been reached already in the first hour it was 96.0% of total substance radionuclide absorbed from the solution, and after the first day it was reached

  3. Interpretation of actinide-distribution data obtained from non-destructive and destructive post-test analyses of an intact-core column of Culebra dolomite.

    PubMed

    Perkins, W G; Lucero, D A

    2001-02-01

    The US Department of Energy (DOE), with technical assistance from Sandia National Laboratories, has successfully received EPA certification and opened the Waste Isolation Pilot Plant (WIPP), a nuclear waste disposal facility located approximately 42 km east of Carlsbad, NM. Performance assessment (PA) analyses indicate that human intrusions by inadvertent, intermittent drilling for resources provide the only credible mechanisms for significant releases of radionuclides from the disposal system. For long-term brine releases, migration pathways through the permeable layers of rock above the Salado formation are important. Major emphasis is placed on the Culebra Member of the Rustler Formation because this is the most transmissive geologic layer overlying the WIPP site. In order to help quantify parameters for the calculated releases, radionuclide transport experiments have been carried out using intact-core columns obtained from the Culebra dolomite member of the Rustler Formation within the WIPP site. This paper deals primarily with results of analyses for 241Pu and 241Am distributions developed during transport experiments in one of these cores. Transport experiments were done using a synthetic brine that simulates Culebra brine at the core recovery location (the WIPP air-intake shaft (AIS)). Hydraulic characteristics (i.e., apparent porosity and apparent dispersion coefficient) for intact-core columns were obtained via experiments using the conservative tracer 22Na. Elution experiments carried out over periods of a few days with tracers 232U and 239Np indicated that these tracers were weakly retarded as indicated by delayed elution of the species. Elution experiments with tracers 241Pu and 241Am were attempted but no elution of either species has been observed to date, including experiments of many months' duration. In order to quantify retardation of the non-eluted species 241Pu and 241Am after a period of brine flow, non-destructive and destructive analyses of

  4. Thorium, uranium and rare earth elements content in lanthanide concentrate (LC) and water leach purification (WLP) residue of Lynas advanced materials plant (LAMP)

    SciTech Connect

    AL-Areqi, Wadeeah M. Majid, Amran Ab. Sarmani, Sukiman

    2014-02-12

    Lynas Advanced Materials Plant (LAMP) has been licensed to produce the rare earths elements since early 2013 in Malaysia. LAMP processes lanthanide concentrate (LC) to extract rare earth elements and subsequently produce large volumes of water leach purification (WLP) residue containing naturally occurring radioactive material (NORM). This residue has been rising up the environmental issue because it was suspected to accumulate thorium with significant activity concentration and has been classified as radioactive residue. The aim of this study is to determine Th-232, U-238 and rare earth elements in lanthanide concentrate (LC) and water leach purification (WLP) residue collected from LAMP and to evaluate the potential radiological impacts of the WLP residue on the environment. Instrumental Neutron Activation Analysis and γ-spectrometry were used for determination of Th, U and rare earth elements concentrations. The results of this study found that the concentration of Th in LC was 1289.7 ± 129 ppm (5274.9 ± 527.6Bq/kg) whereas the Th and U concentrations in WLP were determined to be 1952.9±17.6 ppm (7987.4 ± 71.9 Bq/kg) and 17.2 ± 2.4 ppm respectively. The concentrations of Th and U in LC and WLP samples determined by γ- spectrometry were 1156 ppm (4728 ± 22 Bq/kg) and 18.8 ppm and 1763.2 ppm (7211.4 Bq/kg) and 29.97 ppm respectively. This study showed that thorium concentrations were higher in WLP compare to LC. This study also indicate that WLP residue has high radioactivity of {sup 232}Th compared to Malaysian soil natural background (63 - 110 Bq/kg) and come under preview of Act 304 and regulations. In LC, the Ce and Nd concentrations determined by INAA were 13.2 ± 0.6% and 4.7 ± 0.1% respectively whereas the concentrations of La, Ce, Nd and Sm in WLP were 0.36 ± 0.04%, 1.6%, 0.22% and 0.06% respectively. This result showed that some amount of rare earth had not been extracted and remained in the WLP and may be considered to be reextracted.

  5. Interpretation of actinide-distribution data obtained from non-destructive and destructive post-test analyses of an intact-core column of Culebra dolomite

    NASA Astrophysics Data System (ADS)

    Perkins, W. George; Lucero, Daniel A.

    2001-02-01

    The US Department of Energy (DOE), with technical assistance from Sandia National Laboratories, has successfully received EPA certification and opened the Waste Isolation Pilot Plant (WIPP), a nuclear waste disposal facility located approximately 42 km east of Carlsbad, NM. Performance assessment (PA) analyses indicate that human intrusions by inadvertent, intermittent drilling for resources provide the only credible mechanisms for significant releases of radionuclides from the disposal system. For long-term brine releases, migration pathways through the permeable layers of rock above the Salado formation are important. Major emphasis is placed on the Culebra Member of the Rustler Formation because this is the most transmissive geologic layer overlying the WIPP site. In order to help quantify parameters for the calculated releases, radionuclide transport experiments have been carried out using intact-core columns obtained from the Culebra dolomite member of the Rustler Formation within the WIPP site. This paper deals primarily with results of analyses for 241Pu and 241Am distributions developed during transport experiments in one of these cores. Transport experiments were done using a synthetic brine that simulates Culebra brine at the core recovery location (the WIPP air-intake shaft (AIS)). Hydraulic characteristics (i.e., apparent porosity and apparent dispersion coefficient) for intact-core columns were obtained via experiments using the conservative tracer 22Na. Elution experiments carried out over periods of a few days with tracers 232U and 239Np indicated that these tracers were weakly retarded as indicated by delayed elution of the species. Elution experiments with tracers 241Pu and 241Am were attempted but no elution of either species has been observed to date, including experiments of many months' duration. In order to quantify retardation of the non-eluted species 241Pu and 241Am after a period of brine flow, non-destructive and destructive analyses of

  6. Angular momentum of fission fragments in low energy fission of actinides

    SciTech Connect

    Naik, H.; Dange, S.P.; Singh, R.J.

    2005-01-01

    Independent isomeric yield ratios (IYR) of {sup 128}Sb, {sup 130}Sb, {sup 132}Sb, {sup 131}Te, {sup 133}Te, {sup 132}I, {sup 134}I, {sup 136}I, {sup 135}Xe, and {sup 138}Cs have been determined in fast neutron induced fission of {sup 232}Th, {sup 238}U, {sup 240}Pu, and {sup 244}Cm as well as in thermal neutron induced fission of {sup 232}U and {sup 238}Pu using radiochemical and offline {gamma}-ray spectrometric techniques. From the IYR, fragment angular momenta (J{sub rms}) have been deduced using a spin-dependent statistical model analysis. These data along with the literature data for {sup 230}Th*, {sup 234}U*, {sup 236}U*, {sup 240}Pu*, {sup 242}Pu*, {sup 244}Cm(SF), {sup 246}Cm*, {sup 250}Cf*, and {sup 252}Cf(SF) for fifteen even-Z fissioning systems show the following important features: (i) The J{sub rms} of the odd-Z fission products are higher than those of the even-Z fission products, indicating the odd-even effect. For both the odd-Z and even-Z fission products, the J{sub rms} increase with Z{sub F}{sup 2}/A{sub F}. (ii) The J{sub rms} of fragments with spherical 50-p and 82-n shells are lower compared to those of fragments outside the spherical shell, indicating the effect of shell closure proximity. (iii) The J{sub rms} of the fission products increase with mass number in spite of fluctuations in shell closure proximity and odd-even effects but do not show any correlation with the neutron emission curve. (iv) In all fifteen even-Z fissioning systems from Th to Cf, the yield-weighted J{sub rms} values show an anticorrelation with the elemental yields. (v) The odd-even fluctuation on J{sub rms} does not change drastically from Th to Cf, unlike the proton odd-even effect ({delta}{sub p}) which decreases significantly with the increase of Coulomb parameter (Z{sub F}{sup 2}/A{sub F}{sup 1/3})

  7. Thoron Mitigation System based on charcoal bed for applications in thorium fuel cycle facilities (part 2): Development, characterization, and performance evaluation.

    PubMed

    Sudeep Kumara, K; Sahoo, B K; Gaware, J J; Sapra, B K; Mayya, Y S; Karunakara, N

    2017-06-01

    Exposure due to thoron ((220)Rn) gas and its decay products in a thorium fuel cycle facility handling thorium or (232)U/(233)U mixture compounds is an important issue of radiological concern requiring control and mitigation. Adsorption in a flow-through charcoal bed offers an excellent method of alleviating the release of (220)Rn into occupational and public domain. In this paper, we present the design, development, and characterization of a Thoron Mitigation System (TMS) for industrial application. Systematic experiments were conducted in the TMS for examining the (220)Rn mitigation characteristics with respect to a host of parameters such as flow rate, pressure drop, charcoal grain size, charcoal mass and bed depth, water content, and heat of the carrier gas. An analysis of the experimental data shows that (220)Rn attenuation in a flow through charcoal bed is not exponential with respect to the residence time, L/Ua (L: bed depth; Ua: superficial velocity), but follows a power law behaviour, which can be attributed to the occurrence of large voids due to wall channeling in a flow through bed. The study demonstrates the regeneration of charcoal adsorption capacity degraded due to moisture adsorption, by hot air blowing technique. It is found that the mitigation factor (MF), which is the ratio of the inlet (220)Rn concentration (Cin) to the outlet (220)Rn concentration (Cout), of more than 10(4) for the TMS is easily achievable during continuous operation (>1000 h) at a flow rate of 40 L min(-1) with negligible (<1 cm of water column) pressure drop. The Thoron Mitigation System based on adsorption on charcoal bed offers a compact and effective device to remove (220)Rn from affluent air streams in a space constrained domain. The prototype system has been installed in a thorium fuel cycle facility where it is being evaluated for its long-term performance and overall effectiveness in mitigating (220)Rn levels in the workplace. Copyright © 2017 Elsevier Ltd. All

  8. Thorium, uranium and rare earth elements content in lanthanide concentrate (LC) and water leach purification (WLP) residue of Lynas advanced materials plant (LAMP)

    NASA Astrophysics Data System (ADS)

    AL-Areqi, Wadeeah M.; Majid, Amran Ab.; Sarmani, Sukiman

    2014-02-01

    Lynas Advanced Materials Plant (LAMP) has been licensed to produce the rare earths elements since early 2013 in Malaysia. LAMP processes lanthanide concentrate (LC) to extract rare earth elements and subsequently produce large volumes of water leach purification (WLP) residue containing naturally occurring radioactive material (NORM). This residue has been rising up the environmental issue because it was suspected to accumulate thorium with significant activity concentration and has been classified as radioactive residue. The aim of this study is to determine Th-232, U-238 and rare earth elements in lanthanide concentrate (LC) and water leach purification (WLP) residue collected from LAMP and to evaluate the potential radiological impacts of the WLP residue on the environment. Instrumental Neutron Activation Analysis and γ-spectrometry were used for determination of Th, U and rare earth elements concentrations. The results of this study found that the concentration of Th in LC was 1289.7 ± 129 ppm (5274.9 ± 527.6Bq/kg) whereas the Th and U concentrations in WLP were determined to be 1952.9±17.6 ppm (7987.4 ± 71.9 Bq/kg) and 17.2 ± 2.4 ppm respectively. The concentrations of Th and U in LC and WLP samples determined by γ- spectrometry were 1156 ppm (4728 ± 22 Bq/kg) & 18.8 ppm and 1763.2 ppm (7211.4 Bq/kg) &29.97 ppm respectively. This study showed that thorium concentrations were higher in WLP compare to LC. This study also indicate that WLP residue has high radioactivity of 232Th compared to Malaysian soil natural background (63 - 110 Bq/kg) and come under preview of Act 304 and regulations. In LC, the Ce and Nd concentrations determined by INAA were 13.2 ± 0.6% and 4.7 ± 0.1% respectively whereas the concentrations of La, Ce, Nd and Sm in WLP were 0.36 ± 0.04%, 1.6%, 0.22% and 0.06% respectively. This result showed that some amount of rare earth had not been extracted and remained in the WLP and may be considered to be reextracted.

  9. Top Soils Geochemical and Radioactivity Survey of Naples (Italy) Metropolitan.

    NASA Astrophysics Data System (ADS)

    Somma, R.; De Vivo, B.; Cicchella, D.

    2001-05-01

    The metropolitan area of Naples due to intense human activities is an emblematic area affected by various environmental pollution of soils and waters in addition to hydrogeological volcanic, seismic and bradyseismic hazards. The geology of the area is prevailing represented by volcanics erupted, from the Upper Pleistocene to Recent by Mt. Somma-Vesuvius on the east and the Campi Flegrei fields on the west. The morphology of the metropolitan area of Naples city can be subdivided in flat areas, constituted by reworked pyroclastic terrains, and by hills originated by the overlapping of different welded pyroclastic flows (i.e.: Campanian Ignimbrite and Neapoletan Yellow Tuff) intercalated with pyroclastic deposits of different origins (i.e.: Campi Flegrei, Mt. Somma-Vesuvius, Ischia) and ages. In order to compile a multi-element baseline geochemical and radioactivity mapping of the metropolitan area of the Napoli we have sampled for this study, in situ top soil and imported filling material (mainly soil, volcanic ash, pumice and scoriae). The sampling and radioactivity survey has been carried out on about 200 sampling sites covering an area of about 150 Km2, with a grid of 0.5 x 0.5 km in the urbanised downtown and 1 km x 1 km in the sub urban areas. In each site has been determined a radioactivity by a Scintrex GRS-500 at different emission spectra as total radioactivity (> 0.08 MeV and > 0.40 MeV), 238U (at 1.76 MeV mostly from 214Bi), 232Th (at 2.6 MeV mostly from 208Tl) and 40K (at 1.46 MeV mostly for 40K). The range of values of in situ soils are as follow for the in situ soils (Total radioactivity: 1327- 360 and 114- 47; 238U: 2.6- 1.3; 40K: 8.1- 3.1; 232U: 0.5- 0.1). Analyses of major, metallic elements and pH of each soil sample are in progress, while Pb isotopes compositions, for a selected number of samples, will be determined to discriminate the natural (geogenic) from the anthropogenic components in the soils by versus the anthropogenetic origin. The data

  10. Determination the total neutron yields of several semiconductor compounds using various alpha emitters

    NASA Astrophysics Data System (ADS)

    Abdullah, Ramadhan Hayder; Sabr, Barzan Nehmat

    2016-03-01

    In the present work, the cross-sections of (α,n) reactions available in the literature as a function of α-particle energies for light and medium elements have been rearranged for α-particle energies from near threshold up to 10 MeV in steps of (0.050MeV) using the (Excel and Matlab) computer programs. The obtained data were used to calculate the neutron yields (n/106α) using the quick basic-computer program (Simpson Rules). The stopping powers of alpha particle energies from near threshold to 10 MeV for light and medium elements such as (nat.Be,10B,11B,13C,14N,nat.O,nat.F,nat.Mg,nat.Al,29Si,30Si, nat.P and 46.48Ti) have been calculated using the Zeigler formula. The kinetic energies (Tα) and the branching ratios of each α-emitters such as (211Bi, 210Po, 211Po, 215Po, 217At, 218Rn, 219Rn, 222Rn, 224Ra, 226Ra, 215Th, 228Th, 232U, 234U, 236U, 238U, 238Pu, 239Pu, 241Am, 245Es, 252Fm, 254Fm, 256Fm, 257Fm and 257Md) are taken into consideration to calculate the mean kinetic energy . The polynomial expressions were used to fitting the calculated weighted average of neutron yields (n/106α) for natural light and medium elements such as (Be, B, C, N, O, F, Mg, Al, Si, P and Ti) to determine the adopted neutron yields from the best fitting equation with minimum (CHISQ) at mean kinetic energies of various α-emitters. The total neutron yields (n/s/gx/ppmi) of the mentioned natural light and medium elements have been calculated using the adopted neutron yields (n/106α) from the fitting equations at mean kinetic energies of various α-emitters. The total neutron yields (n/s/gα-emitters/gcompounds) of semiconductor compounds such as (AlN, AlP, BN, BP, SiC, TiO2, BeSiN2, MgCN2, MgSiN2 and MgSiP2) have been calculated by mixing (1gram) of compounds with (1gram) of pure α-emitters using the quick basic computer program. The aim of the present work is to constructed and fabricate the neutron sources theoretically

  11. U(VI) behaviour in hyperalkaline calcite systems

    NASA Astrophysics Data System (ADS)

    Smith, Kurt F.; Bryan, Nicholas D.; Swinburne, Adam N.; Bots, Pieter; Shaw, Samuel; Natrajan, Louise S.; Mosselmans, J. Frederick W.; Livens, Francis R.; Morris, Katherine

    2015-01-01

    The behaviour of U(VI) in hyperalkaline fluid/calcite systems was studied over a range of U(VI) concentrations (5.27 × 10-5 μM to 42.0 μM) and in two high pH systems, young and old synthetic cement leachate in batch sorption experiments. These systems were selected to be representative of young- (pH 13.3) and old-stage (pH 10.5) leachate evolution within a cementitious geological disposal facility. Batch sorption experiments, modelling, extended X-ray absorption fine structure spectroscopy, electron microscopy, small angle X-ray scattering and luminescence spectroscopy were used to define the speciation of U(VI) across the systems of study. At the lowest concentrations (5.27 × 10-5 μM 232U(VI)) significant U removal was observed for both old and young cement leachates, and this was successfully modelled using a first order kinetic adsorption modelling approach. At higher concentrations (>4.20 μM) in the young cement leachate, U(VI) showed no interaction with the calcite surface over an 18 month period. Small angle X-ray scattering techniques indicated that at high U concentrations (42.0 μM) and after 18 months, the U(VI) was present in a colloidal form which had little interaction with the calcite surface and consisted of both primary and aggregated particles with a radius of 7.6 ± 1.1 and 217 ± 24 Å, respectively. In the old cement leachate, luminescence spectroscopy identified two surface binding sites for U(VI) on calcite: in the system with 0.21 μM U(VI), a liebigite-like Ca2UO2(CO3)3 surface complex was identified; at higher U(VI) concentrations (0.42 μM), a second binding site of undetermined coordination was identified. At elevated U(VI) concentrations (>2.10 μM) in old cement leachate, both geochemical data and luminescence spectroscopy suggested that surface mediated precipitation was controlling U(VI) behaviour. A focused ion beam mill was used to create a section across the U(VI) precipitate-calcite interface. Transmission electron

  12. Hybrid Enrichment Assay Methods for a UF6 Cylinder Verification Station: FY10 Progress Report

    SciTech Connect

    Smith, Leon E.; Jordan, David V.; Orton, Christopher R.; Misner, Alex C.; Mace, Emily K.

    2010-08-01

    HPGe verification station at AREVA, and the IAEA’s uncertainty target values for feed, tail and product cylinders. A summary of the major findings from the field measurements and subsequent analysis follows: • Traditional enrichment-meter assay using specially collimated NaI spectrometers and a Square-Wave-Convolute algorithm can achieve uncertainties comparable to HPGe and LaBr for product, natural and depleted cylinders. • Non-traditional signatures measured using NaI spectrometers enable interrogation of the entire cylinder volume and accurate measurement of absolute 235U mass in product, natural and depleted cylinders. • A hybrid enrichment assay method can achieve lower uncertainties than either the traditional or non-traditional methods acting independently because there is a low degree of correlation in the systematic errors of the two individual methods (wall thickness variation and 234U/235U variation, respectively). This work has indicated that the hybrid NDA method has the potential to serve as the foundation for an unattended cylinder verification station. When compared to today’s handheld cylinder-verification approach, such a station would have the following advantages: 1) improved enrichment assay accuracy for product, tail and feed cylinders; 2) full-volume assay of absolute 235U mass; 3) assay of minor isotopes (234U and 232U) important to verification of feedstock origin; single instrumentation design for both Type 30B and Type 48 cylinders; and 4) substantial reduction in the inspector manpower associated with cylinder verification.

  13. OSMOSE experiment representativity studies.

    SciTech Connect

    Aliberti, G.; Klann, R.; Nuclear Engineering Division

    2007-10-10

    The OSMOSE program aims at improving the neutronic predictions of advanced nuclear fuels through measurements in the MINERVE facility at the CEA-Cadarache (France) on samples containing the following separated actinides: Th-232, U-233, U-234, U-235, U-236, U-238, Np-237, Pu-238, Pu-239, Pu-240, Pu-241, Pu-242, Am-241, Am-243, Cm-244 and Cm-245. The goal of the experimental measurements is to produce a database of reactivity-worth measurements in different neutron spectra for the separated heavy nuclides. This database can then be used as a benchmark for integral reactivity-worth measurements to verify and validate reactor analysis codes and integral cross-section values for the isotopes tested. In particular, the OSMOSE experimental program will produce very accurate sample reactivity-worth measurements for a series of actinides in various spectra, from very thermalized to very fast. The objective of the analytical program is to make use of the experimental data to establish deficiencies in the basic nuclear data libraries, identify their origins, and provide guidelines for nuclear data improvements in coordination with international programs. To achieve the proposed goals, seven different neutron spectra can be created in the MINERVE facility: UO2 dissolved in water (representative of over-moderated LWR systems), UO2 matrix in water (representative of LWRs), a mixed oxide fuel matrix, two thermal spectra containing large epithermal components (representative of under-moderated reactors), a moderated fast spectrum (representative of fast reactors which have some slowing down in moderators such as lead-bismuth or sodium), and a very hard spectrum (representative of fast reactors with little moderation from reactor coolant). The different spectra are achieved by changing the experimental lattice within the MINERVE reactor. The experimental lattice is the replaceable central part of MINERVE, which establishes the spectrum at the sample location. This configuration

  14. New Discoveries of Trr and Radiopactive Elements of Phosphogypsum from Romania

    NASA Astrophysics Data System (ADS)

    Maruta Iancu, Aurora; Georgeta Dumitras, Delia; Marincea, Stefan

    2014-05-01

    Phosphogypsum is a technogenic product remaining after the extraction of phosphoric acid from raw phosphate, mainly apatite. Some radioactive elements presented in the phosphate original rock, consisting in apatit, are Ra-226, th-232, U-238, Pb-210, Po-240, K-210, that can be also found in the phosphogypsum. Determination of elements has been carried out on phosphogypsum samples from Turnu Magurele (TR), Valea Calugareasca (VC), Navodari (N) and Bacau (B). The most important minor elements of phosphogypsum are Th and U. The radioactivity of isotopes from Bacau samples of phosphogypsum is: U-238 exceeding (ppm) - 40,50; 31,96; 17,49; 30,00; 31,00 and Th-232 (ppm) - 8,07; 6,07; 6,41; 7,80; 6,41. The radiometric analyzes confirmed that Bacau county phosphogypsum have higher concentrations of U, while the content in Th is lower. The radioactivity of isotopes from samples of Navodari phosphogypsum is U-238 (ppm) - 37,00; 40,97; 10,84; 25,72 and Th-232 (ppm) - 6,82; 7,04; 6,19; 7,55. The radioactivity of isotopes from Turnu Magurele phosphogypsum samples is: U-232 (ppm) - 1,51; 21,92; 28,71; 6,92, 10,79, 11,00, and Th 232 (ppm) - 3,87; 7,29; 10,65; 6,22; 6,77; 5,45. The radiaoactivity of isotopes from Valea Calugareasca samples of phosphogypsum is: U-238 (ppm) - 17,60; 22,35; 17,93; 18,78 and Th-232 (ppm) - 5,98; 7,12; 7,85; 8,07. As in the case of the phosphogypsum analyzed in Bacau, as well as in the zones TM, VC and N, the radiometric analyzes results indicate a high content of U-232 and lower in Th-232. In conclusion, based on the analyzes carried out on samples of phosphogypsum from the four areas, and the higher U and lower Th contents, it follows that we are dealing with phosphogypsum thet results from a sedimentary type rock. Inductively coupled plasma - atomic emission spectrometry (ICP-AES) analyses performed on selected samples of phosphogypsum from the four deposits showed that the contents in the main REE (cerium, erbium, neodymium, thorium, ytterbium) are

  15. 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

    -based fuels to achieve these burnups. Furthermore, thorium-based fuels could also be used as a strategy for reducing the amount of long-lived nuclides (including the minor actinides) and thus the radiotoxicity in spent nuclear fuel. Although the breeding of 233U is a concern, the presence of 232U and its daughter products (namely 208Tl) can aid in making this fuel self-protecting, and/or enough 238U can be added to denature the fissile uranium. From these calculations, it appears that thorium-based fuel for plutonium incineration is superior when compared to uranium-based fuel and should be considered as an alternative to traditional MOX in both current and future/advanced reactor designs.

  16. Nuclear car wash status report, August 2005

    SciTech Connect

    Prussin, S; Slaughter, D; Pruet, J; Descalle, M; Bernstein, A; Hall, J; Accatino, M; Alford, O; Asztalos, S; Church, J; Loshak, A; Madden, N; Manatt, D; Moore, T; Norman, E; Petersen, D

    2005-07-29

    A large majority of US imports arrive at seaports in maritime cargo containers. The number of containers arriving is nearly 10 million per year, each with a cargo of up to 30 tons of various materials. This provides a vulnerable entry point for the importation of a nuclear weapon or its components by a terrorist group. Passive radiation sensors are being deployed at portals to detect radioactive material and portable instruments are carried by port personnel to augment detection. Those instruments can detect the neutrons and g-rays produced by {sup 240}Pu that is normally present in weapons grade plutonium in cases where cargo overburden is not too great. However, {sup 235}U produces almost no neutron output in its normal radioactive decay and its principal {gamma}-radiation is at 186 keV and is readily attenuated by small amounts of wood or packing materials. Impurities such as {sup 232}U, often present in reactor irradiated material at the 100-200 ppt level, can provide a detectable signal through significant cargo overburden but the wide variations among samples of HEU make this an unreliable means of detecting SNM. High quality radiography may be useful in determining that the majority of containers are clearly free of SNM. However, some containers will lead to ambiguous results from radiography and passive radiation sensing. For these reasons active neutron interrogation is proposed as a means to produce fission and thus greatly amplify the radiation output of fissionable material to facilitate its reliable detection even when well shielded by large cargo overburden. Historically, the fission signature utilized as the unique identifying feature of fissionable materials is the detection of delayed neutrons. However, these neutrons have very low yield {approx} 0.017 per fission in {sup 235}U, and their low energy results in very poor penetration of hydrogenous materials such as fuels, water, wood, or agricultural products. That signature alone does not provide

  17. Studies of flerovium and element 115 homologs with macrocyclic extractants

    NASA Astrophysics Data System (ADS)

    Despotopulos, John Dustin

    Study of the chemistry of the heaviest elements, Z ? 104, poses a unique challenge due to their low production cross-sections and short half-lives. Chemistry also must be studied on the one-atom-at-a-time scale, requiring automated, fast, and very efficient chemical schemes. Recent studies of the chemical behavior of copernicium (Cn, element 112) and flerovium (Fl, element 114) together with the discovery of isotopes of these elements with half-lives suitable for chemical studies have spurred a renewed interest in the development of rapid systems designed to study the chemical properties of elements with Z ≥ 114. This dissertation explores both extraction chromatography and solvent extraction as methods for development of a rapid chemical separation scheme for the homologs of flerovium (Pb, Sn, Hg) and element 115 (Bi, Sb), with the goal of developing a chemical scheme that, in the future, can be applied to on-line chemistry of both Fl and element 115. Macrocyclic extractants, specifically crown ethers and their derivatives, were chosen for these studies. Carrier-free radionuclides, used in these studies, of the homologs of Fl and element 115 were obtained by proton activation of high purity metal foils at the Lawrence Livermore National Laboratory (LLNL) Center for Accelerator Mass Spectrometry (CAMS): natIn(p,n)113Sn, natSn(p,n)124Sb, and Au(p,n)197m,gHg. The carrier-free activity was separated from the foils by novel separation schemes based on ion exchange and extraction chromatography techniques. Carrier-free Pb and Bi isotopes were obtained from development of a novel generator based on cation exchange chromatography using the 232U parent to generate 212Pb and 212Bi. Crown ethers show high selectivity for metal ions based on their size compared to the negatively charged cavity of the ether. Extraction by crown ethers occur based on electrostatic ion-dipole interactions between the negatively charged ring atoms (oxygen, sulfur, etc.) and the positively

  18. Special Analysis for the Disposal of the Consolidated Edison Uranium Solidification Project Waste Stream at the Area 5 Radioactive Waste Management Site, Nevada National Security Site, Nye County, Nevada

    SciTech Connect

    NSTec Environmental Management

    2013-01-31

    The purpose of this Special Analysis (SA) is to determine if the Oak Ridge (OR) Consolidated Edison Uranium Solidification Project (CEUSP) uranium-233 (233U) waste stream (DRTK000000050, Revision 0) is acceptable for shallow land burial (SLB) at the Area 5 Radioactive Waste Management Site (RWMS) on the Nevada National Security Site (NNSS). The CEUSP 233U waste stream requires a special analysis because the concentrations of thorium-229 (229Th), 230Th, 232U, 233U, and 234U exceeded their NNSS Waste Acceptance Criteria action levels. The acceptability of the waste stream is evaluated by determining if performance assessment (PA) modeling provides a reasonable expectation that SLB disposal is protective of human health and the environment. The CEUSP 233U waste stream is a long-lived waste with unique radiological hazards. The SA evaluates the long-term acceptability of the CEUSP 233U waste stream for near-surface disposal as a two tier process. The first tier, which is the usual SA process, uses the approved probabilistic PA model to determine if there is a reasonable expectation that disposal of the CEUSP 233U waste stream can meet the performance objectives of U.S. Department of Energy Manual DOE M 435.1-1, “Radioactive Waste Management,” for a period of 1,000 years (y) after closure. The second tier addresses the acceptability of the OR CEUSP 233U waste stream for near-surface disposal by evaluating long-term site stability and security, by performing extended (i.e., 10,000 and 60,000 y) modeling analyses, and by evaluating the effect of containers and the depth of burial on performance. Tier I results indicate that there is a reasonable expectation of compliance with all performance objectives if the OR CEUSP 233U waste stream is disposed in the Area 5 RWMS SLB disposal units. The maximum mean and 95th percentile PA results are all less than the performance objective for 1,000 y. Monte Carlo uncertainty analysis indicates that there is a high likelihood of

  19. Hydrofluoric Acid Corrosion Study of High-Alloy Materials

    SciTech Connect

    Osborne, P.E.

    2002-09-11

    A corrosion study involving high-alloy materials and concentrated hydrofluoric acid (HF) was conducted in support of the Molten Salt Reactor Experiment Conversion Project (CP). The purpose of the test was to obtain a greater understanding of the corrosion rates of materials of construction currently used in the CP vs those of proposed replacement parts. Results of the study will help formulate a change-out schedule for CP parts. The CP will convert slightly less than 40 kg of {sup 233}U from a gas (UF{sub 6}) sorbed on sodium fluoride pellets to a more stable oxide (U{sub 3}O{sub 8}). One by-product of the conversion is the formation of concentrated HF. Six moles of highly corrosive HF are produced for each mole of UF{sub 6} converted. This acid is particularly corrosive to most metals, elastomers, and silica-containing materials. A common impurity found in {sup 233}U is {sup 232}U. This impurity isotope has several daughters that make the handling of the {sup 233}U difficult. Traps of {sup 233}U may have radiation fields of up to 400 R at contact, a situation that makes the process of changing valves or working on the CP more challenging. It is also for this reason that a comprehensive part change-out schedule must be established. Laboratory experiments involving the repeated transfer of HF through 1/2-in. metal tubing and valves have proven difficult due to the corrosivity of the HF upon contact with all wetted parts. Each batch of HF is approximately 1.5 L of 33 wt% HF and is transferred most often as a vapor under vacuum and at temperatures of up to 250 C. Materials used in the HF side of the CP include Hastelloy C-276 and Monel 400 tubing, Haynes 230 and alloy C-276 vessels, and alloy 400 valve bodies with Inconel (alloy 600) bellows. The chemical compositions of the metals discussed in this report are displayed in Table 1. Of particular concern are the almost 30 vendor-supplied UG valves that have the potential for exposure to HF. These valves have been