WorldWideScience

Sample records for basic fission products

  1. Fission Product Library and Resource

    Energy Technology Data Exchange (ETDEWEB)

    Burke, J. T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Padgett, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-09-29

    Fission product yields can be extracted from an irradiated sample by performing gamma ray spectroscopy on the whole sample post irradiation. There are several pitfalls to avoid when trying to determine a specific isotope's fission product yield.

  2. The SPIDER fission fragment spectrometer for fission product yield measurements

    Energy Technology Data Exchange (ETDEWEB)

    Meierbachtol, K.; Tovesson, F. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Shields, D. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Colorado School of Mines, Golden, CO 80401 (United States); Arnold, C. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Blakeley, R. [University of New Mexico, Albuquerque, NM 87131 (United States); Bredeweg, T.; Devlin, M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Hecht, A.A.; Heffern, L.E. [University of New Mexico, Albuquerque, NM 87131 (United States); Jorgenson, J.; Laptev, A. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Mader, D. [University of New Mexico, Albuquerque, NM 87131 (United States); O' Donnell, J.M.; Sierk, A.; White, M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2015-07-11

    The SPectrometer for Ion DEtermination in fission Research (SPIDER) has been developed for measuring mass yield distributions of fission products from spontaneous and neutron-induced fission. The 2E–2v method of measuring the kinetic energy (E) and velocity (v) of both outgoing fission products has been utilized, with the goal of measuring the mass of the fission products with an average resolution of 1 atomic mass unit (amu). The SPIDER instrument, consisting of detector components for time-of-flight, trajectory, and energy measurements, has been assembled and tested using {sup 229}Th and {sup 252}Cf radioactive decay sources. For commissioning, the fully assembled system measured fission products from spontaneous fission of {sup 252}Cf. Individual measurement resolutions were met for time-of-flight (250 ps FWHM), spacial resolution (2 mm FHWM), and energy (92 keV FWHM for 8.376 MeV). Mass yield results measured from {sup 252}Cf spontaneous fission products are reported from an E–v measurement.

  3. Measurement of Fission Product Yields from Fast-Neutron Fission

    Science.gov (United States)

    Arnold, C. W.; Bond, E. M.; Bredeweg, T. A.; Fowler, M. M.; Moody, W. A.; Rusev, G.; Vieira, D. J.; Wilhelmy, J. B.; Becker, J. A.; Henderson, R.; Kenneally, J.; Macri, R.; McNabb, D.; Ryan, C.; Sheets, S.; Stoyer, M. A.; Tonchev, A. P.; Bhatia, C.; Bhike, M.; Fallin, B.; Gooden, M. E.; Howell, C. R.; Kelley, J. H.; Tornow, W.

    2014-09-01

    One of the aims of the Stockpile Stewardship Program is a reduction of the uncertainties on fission data used for analyzing nuclear test data [1,2]. Fission products such as 147Nd are convenient for determining fission yields because of their relatively high yield per fission (about 2%) and long half-life (10.98 days). A scientific program for measuring fission product yields from 235U,238U and 239Pu targets as a function of bombarding neutron energy (0.1 to 15 MeV) is currently underway using monoenergetic neutron beams produced at the 10 MV Tandem Accelerator at TUNL. Dual-fission chambers are used to determine the rate of fission in targets during activation. Activated targets are counted in highly shielded HPGe detectors over a period of several weeks to identify decaying fission products. To date, data have been collected at neutron bombarding energies 4.6, 9.0, 14.5 and 14.8 MeV. Experimental methods and data reduction techniques are discussed, and some preliminary results are presented.

  4. Rapid Separation of Fission Product 141La

    Institute of Scientific and Technical Information of China (English)

    XIA; Wen; YE; Hong-sheng; LIN; Min; CHEN; Ke-sheng; XU; Li-jun; ZHANG; Wei-dong; CHEN; Yi-zhen

    2013-01-01

    141La was separated and purified from fission products in this work for physical measurements aimed at improving the accuracy of its decay parameters.As the impact of 142La and other fission products,cesium(141Cs,142Cs included)was rapid separated from the fission products,141Cs and 142Ba separation was prepared after a cooling time about 25 s when 142Cs decays to daughter 142Ba,141La purification then

  5. Fission-product retention in HTGR fuels

    Energy Technology Data Exchange (ETDEWEB)

    Homan, F.J.; Kania, M.J.; Tiegs, T.N.

    1982-01-01

    Retention data for gaseous and metallic fission products are presented for both Triso-coated and Biso-coated HTGR fuel particles. Performance trends are established that relate fission product retention to operating parameters, such as temperature, burnup, and neutron exposure. It is concluded that Biso-coated particles are not adequately retentive of fission gas or metallic cesium, and Triso-coated particles which retain cesium still lose silver. Design implications related to these performance trends are identified and discussed.

  6. Development of fission Mo-99 production technology

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jin Ho; Choung, W. M.; Lee, K. I. and others

    2000-05-01

    Fission Mo-99 is the only parent nuclide of Tc-99m, an extremely useful tool for mdeical diagnosis, with an estimated usage of greater than 80% of nuclear medicine applicatons. HEU and LEU targets to optimize in HANARO irradiation condition suggested and designed for domestic production of fission Mo-99. The optimum process conditions are established in each unit process to meet quality requirements of fission Mo-99 products, and the results of performance test in combined process show Mo separation and purification yield of the above 97%. The concept of Tc generator production process is established, and the result of performance test show Tc production yield of 98.4% in Tc generator procuction process. The drafts is prepared for cooperation of technical cooperation and business investment with foreign country. Evaluation on economic feasibility is accompanied for fission Mo-99 and Tc-99m generator production.

  7. Actinide and fission product separation and transmutation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1991-07-01

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

  8. Modeling Fission Product Sorption in Graphite Structures

    Energy Technology Data Exchange (ETDEWEB)

    Szlufarska, Izabela [University of Wisconsin, Madison, WI (United States); Morgan, Dane [University of Wisconsin, Madison, WI (United States); Allen, Todd [University of Wisconsin, Madison, WI (United States)

    2013-04-08

    The goal of this project is to determine changes in adsorption and desorption of fission products to/from nuclear-grade graphite in response to a changing chemical environment. First, the project team will employ principle calculations and thermodynamic analysis to predict stability of fission products on graphite in the presence of structural defects commonly observed in very high- temperature reactor (VHTR) graphites. Desorption rates will be determined as a function of partial pressure of oxygen and iodine, relative humidity, and temperature. They will then carry out experimental characterization to determine the statistical distribution of structural features. This structural information will yield distributions of binding sites to be used as an input for a sorption model. Sorption isotherms calculated under this project will contribute to understanding of the physical bases of the source terms that are used in higher-level codes that model fission product transport and retention in graphite. The project will include the following tasks: Perform structural characterization of the VHTR graphite to determine crystallographic phases, defect structures and their distribution, volume fraction of coke, and amount of sp2 versus sp3 bonding. This information will be used as guidance for ab initio modeling and as input for sorptivity models; Perform ab initio calculations of binding energies to determine stability of fission products on the different sorption sites present in nuclear graphite microstructures. The project will use density functional theory (DFT) methods to calculate binding energies in vacuum and in oxidizing environments. The team will also calculate stability of iodine complexes with fission products on graphite sorption sites; Model graphite sorption isotherms to quantify concentration of fission products in graphite. The binding energies will be combined with a Langmuir isotherm statistical model to predict the sorbed concentration of fission

  9. Recovery and use of fission product noble metals

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, G.A.; Rohmann, C.A.; Perrigo, L.D.

    1980-06-01

    Noble metals in fission products are of strategic value. Market prices for noble metals are rising more rapidly than recovery costs. A promising concept has been developed for recovery of noble metals from fission product waste. Although the assessment was made only for the three noble metal fission products (Rh, Pd, Ru), there are other fission products and actinides which have potential value. (DLC)

  10. Fission Product Sorptivity in Graphite

    Energy Technology Data Exchange (ETDEWEB)

    Tompson, Jr., Robert V. [Univ. of Missouri, Columbia, MO (United States); Loyalka, Sudarshan [Univ. of Missouri, Columbia, MO (United States); Ghosh, Tushar [Univ. of Missouri, Columbia, MO (United States); Viswanath, Dabir [Univ. of Missouri, Columbia, MO (United States); Walton, Kyle [Univ. of Missouri, Columbia, MO (United States); Haffner, Robert [Univ. of Missouri, Columbia, MO (United States)

    2015-04-01

    Both adsorption and absorption (sorption) of fission product (FP) gases on/into graphite are issues of interest in very high temperature reactors (VHTRs). In the original proposal, we proposed to use packed beds of graphite particles to measure sorption at a variety of temperatures and to use an electrodynamic balance (EDB) to measure sorption onto single graphite particles (a few μm in diameter) at room temperature. The use of packed beds at elevated temperature is not an issue. However, the TPOC requested revision of this initial proposal to included single particle measurements at elevated temperatures up to 1100 °C. To accommodate the desire of NEUP to extend the single particle EDB measurements to elevated temperatures it was necessary to significantly revise the plan and the budget. These revisions were approved. In the EDB method, we levitate a single graphite particle (the size, surface characteristics, morphology, purity, and composition of the particle can be varied) or agglomerate in the balance and measure the sorption of species by observing the changes in mass. This process involves the use of an electron stepping technique to measure the total charge on a particle which, in conjunction with the measured suspension voltages for the particle, allows for determinations of mass and, hence, of mass changes which then correspond to measurements of sorption. Accommodating elevated temperatures with this type of system required a significant system redesign and required additional time that ultimately was not available. These constraints also meant that the grant had to focus on fewer species as a result. Overall, the extension of the original proposed single particle work to elevated temperatures added greatly to the complexity of the proposed project and added greatly to the time that would eventually be required as well. This means that the bulk of the experimental progress was made using the packed bed sorption systems. Only being able to recruit one

  11. Actinide and fission product separation and transmutation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1993-07-01

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

  12. Fission Product Decay Heat Calculations for Neutron Fission of 232Th

    Science.gov (United States)

    Son, P. N.; Hai, N. X.

    2016-06-01

    Precise information on the decay heat from fission products following times after a fission reaction is necessary for safety designs and operations of nuclear-power reactors, fuel storage, transport flasks, and for spent fuel management and processing. In this study, the timing distributions of fission products' concentrations and their integrated decay heat as function of time following a fast neutron fission reaction of 232Th were exactly calculated by the numerical method with using the DHP code.

  13. Actinide and fission product partitioning and transmutation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-07-01

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

  14. Research on Nuclear Reaction Network Equation for Fission Product Nuclides

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Nuclear Reaction Network Equation calculation system for fission product nuclides was developed. With the system, the number of the fission product nuclides at different time can be calculated in the different neutron field intensity and neutron energy spectra

  15. Development of fission Mo-99 production technology

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jin Ho; Choung, W. M.; Lee, K. I. and others

    2001-05-01

    This R and D project is planed to supply domestic demands of Mo-99 through fission route, and consequently this project will be expected to rise up utilization of HANARO and KAERI's capability for marketing extension into domestic and oversea radiopharmaceutical market. HEU and LEU target types are decided and designed for fission Mo-99 production in domestic. Experimental study of target fabrication technology was performed and developed processing equipments. And conceptual design of target loading/unloading in/from HANARO device are performed. Tracer test of Mo-99 separation and purification process was performed, test results reach to Mo-99 recovery yield above 80% and decontamination factor above 1600. Combined Mo-99 separation and purification process was decided for hot test scheduled from next year, and performance test was performed. Conceptual design for modification of existing hot cell for fission Mo-99 production facility was performed and will be used for detail design. Assumption for the comparison of LEU and HEU target in fission Mo-99 production process were suggested and compared of merits and demerits in view of fabrication technology and economy feasibility.

  16. Decay spectroscopy of exotic fission products

    Science.gov (United States)

    Rykaczewski, Krzysztof

    2014-09-01

    The beta decay studies of exotic fission products have been performed at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory. The scientific program was focused on the beta-strength function measurements and resulting new half-lives and beta-delayed neutron properties. These observables are important for nuclear structure analysis and modeling of the nucleosynthesis within rapid neutron capture process. The highlights include ten new beta half-lives and several Pn branching ratios including an observation of beta-delayed two-neutron emitter 86Ga. In addition, the measurements of the beta-strength within beta-gamma emission window were performed using a Modular Total Absorption Spectrometer for 22 fission products. These MTAS results are also important for the analysis of reactor anti-neutrino anomaly. The beta decay studies of exotic fission products have been performed at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory. The scientific program was focused on the beta-strength function measurements and resulting new half-lives and beta-delayed neutron properties. These observables are important for nuclear structure analysis and modeling of the nucleosynthesis within rapid neutron capture process. The highlights include ten new beta half-lives and several Pn branching ratios including an observation of beta-delayed two-neutron emitter 86Ga. In addition, the measurements of the beta-strength within beta-gamma emission window were performed using a Modular Total Absorption Spectrometer for 22 fission products. These MTAS results are also important for the analysis of reactor anti-neutrino anomaly. Supported by the U.S. DOE Office of Nuclear Physics under Contracts DE-AC05-00R22725 (ORNL), DE-FG02-96ER40983 (UTK).

  17. Actinide and fission product partitioning and transmutation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-07-01

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

  18. SPIDER Progress Towards High Resolution Correlated Fission Product Data

    Science.gov (United States)

    Shields, Dan; Meierbachtol, Krista; Tovesson, Fredrik; Arnold, Charles; Blackeley, Rick; Bredeweg, Todd; Devlin, Matt; Hecht, Adam; Jandel, Marian; Jorgenson, Justin; Nelson, Ron; White, Morgan; Spider Team

    2014-09-01

    The SPIDER detector (SPectrometer for Ion DEtermination in fission Research) is under development with the goal of obtaining high-resolution, high-efficiency, correlated fission product data needed for many applications including the modeling of next generation nuclear reactors, stockpile stewardship, and the fundamental understanding of the fission process. SPIDER simultaneously measures velocity and energy of both fission products to calculate fission product yields (FPYs), neutron multiplicity (ν), and total kinetic energy (TKE). A detailed description of the prototype SPIDER detector components will be presented. Characterization measurements with alpha and spontaneous fission sources will also be discussed. LA-UR-14-24875. The SPIDER detector (SPectrometer for Ion DEtermination in fission Research) is under development with the goal of obtaining high-resolution, high-efficiency, correlated fission product data needed for many applications including the modeling of next generation nuclear reactors, stockpile stewardship, and the fundamental understanding of the fission process. SPIDER simultaneously measures velocity and energy of both fission products to calculate fission product yields (FPYs), neutron multiplicity (ν), and total kinetic energy (TKE). A detailed description of the prototype SPIDER detector components will be presented. Characterization measurements with alpha and spontaneous fission sources will also be discussed. LA-UR-14-24875. This work is in part supported by LANL Laboratory Directed Research and Development Projects 20110037DR and 20120077DR.

  19. Dual-fission chamber and neutron beam characterization for fission product yield measurements using monoenergetic neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Bhatia, C.; Fallin, B. [Department of Physics, Duke University, Durham, NC 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Gooden, M.E., E-mail: megooden@tunl.duke.edu [Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Department of Physics, North Carolina State University, Raleigh, NC 27605 (United States); Howell, C.R. [Department of Physics, Duke University, Durham, NC 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Kelley, J.H. [Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Department of Physics, North Carolina State University, Raleigh, NC 27605 (United States); Tornow, W. [Department of Physics, Duke University, Durham, NC 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Arnold, C.W.; Bond, E.M.; Bredeweg, T.A.; Fowler, M.M.; Moody, W.A.; Rundberg, R.S.; Rusev, G.; Vieira, D.J.; Wilhelmy, J.B. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Becker, J.A.; Macri, R.; Ryan, C.; Sheets, S.A.; Stoyer, M.A. [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); and others

    2014-09-01

    A program has been initiated to measure the energy dependence of selected high-yield fission products used in the analysis of nuclear test data. We present out initial work of neutron activation using a dual-fission chamber with quasi-monoenergetic neutrons and gamma-counting method. Quasi-monoenergetic neutrons of energies from 0.5 to 15 MeV using the TUNL 10 MV FM tandem to provide high-precision and self-consistent measurements of fission product yields (FPY). The final FPY results will be coupled with theoretical analysis to provide a more fundamental understanding of the fission process. To accomplish this goal, we have developed and tested a set of dual-fission ionization chambers to provide an accurate determination of the number of fissions occurring in a thick target located in the middle plane of the chamber assembly. Details of the fission chamber and its performance are presented along with neutron beam production and characterization. Also presented are studies on the background issues associated with room-return and off-energy neutron production. We show that the off-energy neutron contribution can be significant, but correctable, while room-return neutron background levels contribute less than <1% to the fission signal.

  20. Ceramic Hosts for Fission Products Immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Peter C Kong

    2010-07-01

    Natural spinel, perovskite and zirconolite rank among the most leach resistant of mineral forms. They also have a strong affinity for a large number of other elements and including actinides. Specimens of natural perovskite and zirconolite were radioisotope dated and found to have survived at least 2 billion years of natural process while still remain their loading of uranium and thorium . Developers of the Synroc waste form recognized and exploited the capability of these minerals to securely immobilize TRU elements in high-level waste . However, the Synroc process requires a relatively uniform input and hot pressing equipment to produce the waste form. It is desirable to develop alternative approaches to fabricate these durable waste forms to immobilize the radioactive elements. One approach is using a high temperature process to synthesize these mineral host phases to incorporate the fission products in their crystalline structures. These mineral assemblages with immobilized fission products are then isolated in a durable high temperature glass for periods measured on a geologic time scale. This is a long term research concept and will begin with the laboratory synthesis of the pure spinel (MgAl2O4), perovskite (CaTiO3) and zirconolite (CaZrTi2O7) from their constituent oxides. High temperature furnace and/or thermal plasma will be used for the synthesis of these ceramic host phases. Nonradioactive strontium oxide will be doped into these ceramic phases to investigate the development of substitutional phases such as Mg1-xSrxAl2O4, Ca1-xSrxTiO3 and Ca1-xSrxZrTi2O7. X-ray diffraction will be used to establish the crystalline structures of the pure ceramic hosts and the substitution phases. Scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDX) will be performed for product morphology and fission product surrogates distribution in the crystalline hosts. The range of strontium doping is planned to reach the full substitution of the divalent

  1. Basic Physics Data: Measurement of Neutron Multiplicity from Induced Fission

    Energy Technology Data Exchange (ETDEWEB)

    Pozzi, Sara [Univ. of Michigan, Ann Arbor, MI (United States); Haight, Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-05-04

    From October 1 to October 17 a team of researchers from UM visited the LANSCE facility for an experiment during beam-time allotted from October 4 to October 17. A total of 24 detectors were used at LANSCE including liquid organic scintillation detectors (EJ-309), NaI scintillation detectors, and Li-6 enriched glass detectors. It is a double time-offlight (TOF) measurement using spallation neutrons generated by a target bombarded with pulsed high-energy protons. The neutrons travel to an LLNL-manufactured parallel plate avalanche chamber (PPAC) loaded with thin U-235 foils in which fission events are induced. The generated fission neutrons and photons are then detected in a detector array designed and built at UM and shipped to LANSCE. Preparations were made at UM, where setup and proposed detectors were tested. The UM equipment was then shipped to LANSCE for use at the 15L beam of the weapons neutron research (WNR) facility.

  2. Immobilization of fission products in phosphate ceramic waste forms

    Energy Technology Data Exchange (ETDEWEB)

    Singh, D. [Argonne National Lab., IL (United States)

    1996-10-01

    The goal of this project is to develop and demonstrate the feasibility of a novel low-temperature solidification/stabilization (S/S) technology for immobilizing waste streams containing fission products such as cesium, strontium, and technetium in a chemically bonded phosphate ceramic. This technology can immobilize partitioned tank wastes and decontaminate waste streams containing volatile fission products.

  3. Fission Product Neutron Cross Section Library and Its Reliability Assessment

    Institute of Scientific and Technical Information of China (English)

    QIAN; Jing; SUN; Zheng-jun; LIU; Ting-jin; SHU; Neng-chuan

    2013-01-01

    A complete library of neutron cross section data has been developed for fission product nuclides.It contains data for 1 121 fission product nuclides of mass number A from 66 to 172 and atomic numbers Z from 22 to 72,where involves a lot of very short-lived radioactive ones.The data were taken from better

  4. (Fuel, fission product, and graphite technology)

    Energy Technology Data Exchange (ETDEWEB)

    Stansfield, O.M.

    1990-07-25

    Travel to the Forschungszentrum (KFA) -- Juelich described in this report was for the purpose of participating in the annual meeting of subprogram managers for the US/DOE Umbrella Agreement for Fuel, Fission Product, and Graphite Technology. At this meeting the highlights of the cooperative exchange were reviewed for the time period June 1989 through June 1990. The program continues to contribute technology in an effective way for both countries. Revision 15 of the Subprogram Plan will be issued as a result of the meeting. There was interest expressed by KFA management in the level of support received from the NPR program and in potential participation in the COMEDIE loop experiment being conducted at the CEA.

  5. Fission-product SiC reaction in HTGR fuel

    Energy Technology Data Exchange (ETDEWEB)

    Montgomery, F.

    1981-07-13

    The primary barrier to release of fission product from any of the fuel types into the primary circuit of the HTGR are the coatings on the fuel particles. Both pyrolytic carbon and silicon carbide coatings are very effective in retaining fission gases under normal operating conditions. One of the possible performance limitations which has been observed in irradiation tests of TRISO fuel is chemical interaction of the SiC layer with fission products. This reaction reduces the thickness of the SiC layer in TRISO particles and can lead to release of fission products from the particles if the SiC layer is completely penetrated. The experimental section of this report describes the results of work at General Atomic concerning the reaction of fission products with silicon carbide. The discussion section describes data obtained by various laboratories and includes (1) a description of the fission products which have been found to react with SiC; (2) a description of the kinetics of silicon carbide thinning caused by fission product reaction during out-of-pile thermal gradient heating and the application of these kinetics to in-pile irradiation; and (3) a comparison of silicon carbide thinning in LEU and HEU fuels.

  6. Chemical state of fission products in irradiated uranium carbide fuel

    Science.gov (United States)

    Arai, Yasuo; Iwai, Takashi; Ohmichi, Toshihiko

    1987-12-01

    The chemical state of fission products in irradiated uranium carbide fuel has been estimated by equilibrium calculation using the SOLGASMIX-PV program. Solid state fission products are distributed to the fuel matrix, ternary compounds, carbides of fission products and intermetallic compounds among the condensed phases appearing in the irradiated uranium carbide fuel. The chemical forms are influenced by burnup as well as stoichiometry of the fuel. The results of the present study almost agree with the experimental ones reported for burnup simulated carbides.

  7. The Oklo natural reactor: Cumulative fission yields and retentivity of the symmetric mass region fission products

    Science.gov (United States)

    De Laeter, J. R.; Rosman, K. J. R.; Smith, C. L.

    1980-10-01

    Solid source mass spectrometry has been used to determine the relative cumulative fission yields of five elements in three samples of uranium ore from reactor zones in the Oklo mine site. Eighteen fission chains covering the mass range from 105 ≤ A ≤ 130 have been measured for Pd, Ag, Cd, Sn and Te. These measurements have enabled a number of nuclear parameters to be calculated including the relative proportions of 235U, 238U and 239Pu involved in the fission process. The concentration of the five elements in the Oklo samples have also been measured using the stable isotope dilution technique. These values have then been compared to the estimates of the amount of these elements produced by fission under the conditions that are appropriate to the three samples. This procedure enables the retentivity of the elements in the reactor zones to be evaluated. Our work confirms the fact that Pd and Te are retained almost in their entirety in the samples, whereas the other three elements have been partially lost from the reactor site. Almost all the Cd fission products have been lost, and more than 50% of the Ag and Sn fission-produced material has been removed.

  8. B-Plant fission product flowsheets: Part 2

    Energy Technology Data Exchange (ETDEWEB)

    Rey, G.

    1961-09-29

    The technical bases for Phase I of the Fission Product Program have previously been presented for Phase I design. This report represents its sequel for Phase II of the program. Phase I provides the means of segregating, concentrating, and aging crude fission product fractions with market value. Phase II is to provide the means for single-line purification and packaging of megacurie quantities of fission products (principally strontium-90). The technical bases for Phase II project scoping studies are presented herein in the form of process flowsheets and tabulated data. Equipment needs are also described. Conceptual processes and flow diagrams for Phase III are presented for the Waste Management Program and the Fission Product Program.

  9. Thermodynamics of fission products in UO2+-x

    Energy Technology Data Exchange (ETDEWEB)

    Nerikar, Pankaj V [Los Alamos National Laboratory

    2009-01-01

    The stabilities of selected fission products - Xe, Cs, and Sr - are investigated as a function of non-stoichiometry x in UO{sub 2{+-}x}. In particular, density functional theory (OFT) is used to calculate the incorporation and solution energies of these fission products at the anion and cation vacancy sites, at the divacancy, and at the bound Schottky defect. In order to reproduce the correct insulating state of UO{sub 2}, the DFT calculations are performed using spin polarization and with the Hubbard U tenn. In general, higher charge defects are more soluble in the fuel matrix and the solubility of fission products increases as the hyperstoichiometry increases. The solubility of fission product oxides is also explored. CS{sub 2}O is observed as a second stable phase and SrO is found to be soluble in the UO{sub 2} matrix for all stoichiometries. These observations mirror experimentally observed phenomena.

  10. Studies on the Separation of Cesium From Fission Products

    Institute of Scientific and Technical Information of China (English)

    QIANLi-juan; ZHANGSheng-dong; GUOJing-ru; CUIAn-zhi; YANGLei; WUWang-suo

    2003-01-01

    135Cs is a long-life fission product. When measuring its thermal cross section, we must separate radiochemical purity cesium from fission products. Except for decontaminating radio- nuclides, others which can be activated must be avoided to come into solution. So ion exchanger is used. Inorganic ion exchangers have received increased attention because of their high resistance to radiation and their very efficient separation of alkali metal ions.

  11. Conceptual design report of hot cell modification and process for fission Mo-99 production

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jin Ho; Choung, W. M.; Lee, K. I.; Hwang, D. S.; Kim, Y. K.; Park, K. B.; Jung, Y. J.; Kim, D. S.; Park, Y. C

    2001-05-01

    In this conceptual design report, the basic data and design guides for detail design of fission Mo-99 production process and hot cell modification are included.The basic data and design guides for detail design of fission Mo-99 production process contains following contents. -design capacity, the basic process, process flow diagram, process material balance, process data. The basic data and design guides for modification of existing hot cell contains following contents. - plot plan of hot cell facility, the plan for shield reinforcement of hot cell, the plan for management and storage of high level liquid wastes, the plan of ventilation system, the plan for modification of auxiliary facilities. And also, the results of preliminary safety analysis(normal operation and accidents) and criticality analysis are included in this conceptual design report.

  12. Interactions of fission product vapours with aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Benson, C.G.; Newland, M.S. [AEA Technology, Winfrith (United Kingdom)

    1996-12-01

    Reactions between structural and reactor materials aerosols and fission product vapours released during a severe accident in a light water reactor (LWR) will influence the magnitude of the radiological source term ultimately released to the environment. The interaction of cadmium aerosol with iodine vapour at different temperatures has been examined in a programme of experiments designed to characterise the kinetics of the system. Laser induced fluorescence (LIF) is a technique that is particularly amenable to the study of systems involving elemental iodine because of the high intensity of the fluorescence lines. Therefore this technique was used in the experiments to measure the decrease in the concentration of iodine vapour as the reaction with cadmium proceeded. Experiments were conducted over the range of temperatures (20-350{sup o}C), using calibrated iodine vapour and cadmium aerosol generators that gave well-quantified sources. The LIF results provided information on the kinetics of the process, whilst examination of filter samples gave data on the composition and morphology of the aerosol particles that were formed. The results showed that the reaction of cadmium with iodine was relatively fast, giving reaction half-lives of approximately 0.3 s. This suggests that the assumption used by primary circuit codes such as VICTORIA that reaction rates are mass-transfer limited, is justified for the cadmium-iodine reaction. The reaction was first order with respect to both cadmium and iodine, and was assigned as pseudo second order overall. However, there appeared to be a dependence of aerosol surface area on the overall rate constant, making the precise order of the reaction difficult to assign. The relatively high volatility of the cadmium iodide formed in the reaction played an important role in determining the composition of the particles. (author) 23 figs., 7 tabs., 22 refs.

  13. Relative fission product yield determination in the USGS TRIGA Mark I reactor

    Science.gov (United States)

    Koehl, Michael A.

    Fission product yield data sets are one of the most important and fundamental compilations of basic information in the nuclear industry. This data has a wide range of applications which include nuclear fuel burnup and nonproliferation safeguards. Relative fission yields constitute a major fraction of the reported yield data and reduce the number of required absolute measurements. Radiochemical separations of fission products reduce interferences, facilitate the measurement of low level radionuclides, and are instrumental in the analysis of low-yielding symmetrical fission products. It is especially useful in the measurement of the valley nuclides and those on the extreme wings of the mass yield curve, including lanthanides, where absolute yields have high errors. This overall project was conducted in three stages: characterization of the neutron flux in irradiation positions within the U.S. Geological Survey TRIGA Mark I Reactor (GSTR), determining the mass attenuation coefficients of precipitates used in radiochemical separations, and measuring the relative fission products in the GSTR. Using the Westcott convention, the Westcott flux, modified spectral index, neutron temperature, and gold-based cadmium ratios were determined for various sampling positions in the USGS TRIGA Mark I reactor. The differential neutron energy spectrum measurement was obtained using the computer iterative code SAND-II-SNL. The mass attenuation coefficients for molecular precipitates were determined through experiment and compared to results using the EGS5 Monte Carlo computer code. Difficulties associated with sufficient production of fission product isotopes in research reactors limits the ability to complete a direct, experimental assessment of mass attenuation coefficients for these isotopes. Experimental attenuation coefficients of radioisotopes produced through neutron activation agree well with the EGS5 calculated results. This suggests mass attenuation coefficients of molecular

  14. Fission-product releases from a PHWR terminal debris bed

    Energy Technology Data Exchange (ETDEWEB)

    Brown, M.J.; Bailey, D.G., E-mail: morgan.brown@cnl.ca [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada)

    2016-06-15

    During an unmitigated severe accident in a pressurized heavy water reactor (PHWR) with horizontal fuel channels, the core may disassemble and relocate to the bottom of the calandria vessel. The resulting heterogeneous in-vessel terminal debris bed (TDB) would likely be quenched by any remaining moderator, and some of the decay heat would be conducted through the calandria vessel shell to the surrounding reactor vault or shield tank water. As the moderator boiled off, the solid debris bed would transform into a more homogeneous molten corium pool located between top and bottom crusts. Until recently, the severe accident code MAAP-CANDU assumed that unreleased volatile and semi-volatile fission products remained in the TDB until after calandria vessel failure, due to low diffusivity through the top crust and the lack of gases or steam to flush released fission products from the debris. However, national and international experimental results indicate this assumption is unlikely; instead, high- and medium-volatility fission products would be released from a molten debris pool, and their volatility and transport should be taken into account in TDB modelling. The resulting change in the distribution of fission products within the reactor and containment, and the associated decay heat, can have significant effects upon the progression of the accident and fission-product releases to the environment. This article describes a postulated PHWR severe accident progression to generate a TDB and the effects of fission-product releases from the terminal debris, using the simple release model in the MAAP-CANDU severe accident code. It also provides insights from various experimental programs related to fission-product releases from core debris, and their applicability to the MAAP-CANDU TDB model. (author)

  15. Evaluation and compilation of fission product yields 1993

    Energy Technology Data Exchange (ETDEWEB)

    England, T.R.; Rider, B.F.

    1995-12-31

    This document is the latest in a series of compilations of fission yield data. Fission yield measurements reported in the open literature and calculated charge distributions have been used to produce a recommended set of yields for the fission products. The original data with reference sources, and the recommended yields axe presented in tabular form. These include many nuclides which fission by neutrons at several energies. These energies include thermal energies (T), fission spectrum energies (F), 14 meV High Energy (H or HE), and spontaneous fission (S), in six sets of ten each. Set A includes U235T, U235F, U235HE, U238F, U238HE, Pu239T, Pu239F, Pu241T, U233T, Th232F. Set B includes U233F, U233HE, U236F, Pu239H, Pu240F, Pu241F, Pu242F, Th232H, Np237F, Cf252S. Set C includes U234F, U237F, Pu240H, U234HE, U236HE, Pu238F, Am241F, Am243F, Np238F, Cm242F. Set D includes Th227T, Th229T, Pa231F, Am241T, Am241H, Am242MT, Cm245T, Cf249T, Cf251T, Es254T. Set E includes Cf250S, Cm244S, Cm248S, Es253S, Fm254S, Fm255T, Fm256S, Np237H, U232T, U238S. Set F includes Cm243T, Cm246S, Cm243F, Cm244F, Cm246F, Cm248F, Pu242H, Np237T, Pu240T, and Pu242T to complete fission product yield evaluations for 60 fissioning systems in all. This report also serves as the primary documentation for the second evaluation of yields in ENDF/B-VI released in 1993.

  16. Trapping technology for gaseous fission products from voloxidation process

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Jin Myeong; Park, J. J.; Park, G. I.; Jung, I. H.; Lee, H. H.; Kim, G. H.; Yang, M. S

    2005-05-15

    The objective of this report is to review the different technologies for trapping the gaseous wastes containing Cs, Ru, Tc, {sup 14}C, Kr, Xe, I and {sup 3}H from a voloxidation process. Based on literature reviews and KAERI's experimental results on the gaseous fission products trapping, appropriate trapping method for each fission product has been selected considering process reliability, simplicity, decontamination factor, availability, and disposal. Specifically, the most promising trapping method for each fission product has been proposed for the development of the INL off-gas trapping system. A fly ash filter is proposed as a trapping media for a cesium trapping unit. In addition, a calcium filter is proposed as a trapping media for ruthenium, technetium, and {sup 14}C trapping unit. In case of I trapping unit, AgX is proposed. For Kr and Xe, adsorption on solid is proposed. SDBC (Styrene Divinyl Benzene Copolymer) is also proposed as a conversion media to HTO for {sup 3}H. This report will be used as a useful means for analyzing the known trapping technologies and help selecting the appropriate trapping methods for trapping volatile and semi-volatile fission products, long-lived fission products, and major heat sources generated from a voloxidation process. It can also be used to design an off-gas treatment system.

  17. Comparison of Fission Product Yields and Their Impact

    Energy Technology Data Exchange (ETDEWEB)

    S. Harrison

    2006-02-01

    This memorandum describes the Naval Reactors Prime Contractor Team (NRPCT) Space Nuclear Power Program (SNPP) interest in determining the expected fission product yields from a Prometheus-type reactor and assessing the impact of these species on materials found in the fuel element and balance of plant. Theoretical yield calculations using ORIGEN-S and RACER computer models are included in graphical and tabular form in Attachment, with focus on the desired fast neutron spectrum data. The known fission product interaction concerns are the corrosive attack of iron- and nickel-based alloys by volatile fission products, such as cesium, tellurium, and iodine, and the radiological transmutation of krypton-85 in the coolant to rubidium-85, a potentially corrosive agent to the coolant system metal piping.

  18. Development of Calculation Code for Fission Product and Corrosion Product in PWR’s Primary Loop

    Institute of Scientific and Technical Information of China (English)

    XU; Zhi-long; WAN; Hai-xia; SHAO; Jing; WU; Xiao-chun; LI; Long; LIU; Xing-min; KE; Guo-tu

    2015-01-01

    With the basis of study on generation,release and migration of fission product,calculation model for each of the above processes was developed,and calculation method for source term of PWR fission products was established.Study on source term of corrosion product in primary loop was been done.Based on the study of corrosion,

  19. Fission Product Yields from Fission Spectrum n+ 239Pu for ENDF/B-VII.1

    Science.gov (United States)

    Chadwick, M. B.; Kawano, T.; Barr, D. W.; Mac Innes, M. R.; Kahler, A. C.; Graves, T.; Selby, H.; Burns, C. J.; Inkret, W. C.; Keksis, A. L.; Lestone, J. P.; Sierk, A. J.; Talou, P.

    2010-12-01

    We describe a new cumulated fission product yield (FPY) evaluation for fission spectrum neutrons on plutonium that updates the ENDF/B-VI evaluation by England and Rider, for the forthcoming ENDF/B-VII.1 database release. We focus on FPs that are needed for high accuracy burnup assessments; that is, for inferring the number of fissions in a neutron environment. Los Alamos conducted an experiment in the 1970s in the Bigten fast critical assembly to determine fission product yields as part of the Interlaboratory Reaction Rate (ILRR) collaboration, and this has defined the Laboratory's fission standard to this day. Our evaluation includes use of the LANL-ILRR measurements (not previously available to evaluators) as well as other Laboratory FPY measurements published in the literature, especially the high-accuracy mass spectrometry data from Maeck and others. Because the measurement database for some of the FPs is small — especially for 99Mo — we use a meta-analysis that incorporates insights from other accurately-measured benchmark FP data, using R-value ratio measurements. The meta-analysis supports the FP measurements from the LANL-ILRR experiment. Differences between our new evaluations and ENDF/B-VI are small for some FPs (less than 1-2%-relative for 95Zr, 140Ba, 144Ce), but are larger for 99Mo (4%-relative) and 147Nd (5%-relative, at 1.5 MeV) respectively. We present evidence for an incident neutron energy dependence to the 147Nd fission product yield that accounts for observed differences in the FPY at a few-hundred keV average energy in fast reactors versus measurements made at higher average neutron energies in Los Alamos' fast critical assemblies. Accounting for such FPY neutron energy dependencies is important if one wants to reach a goal of determining the number of fissions to accuracies of 1-2%. An evaluation of the energy-dependence of fission product yields is given for all A values based on systematical trends in the measured data, with a focus on

  20. Evaluation of fission product yields from fission spectrum n+239Pu using a meta analysis of benchmark data

    Science.gov (United States)

    Chadwick, Mark B.

    2009-10-01

    Los Alamos conducted a dual fission-chamber experiment in the 1970s in the Bigten critical assembly to determine fission product data in a fast (fission neutron spectrum) environment, and this defined the Laboratory's fission basis today. We describe how the data from this experiment are consistent with other benchmark fission product yield measurements for 95,97Zr, 140Ba, 143,144Ce, 137Cs from the NIST-led ILRR fission chamber experiments, and from Maeck's mass-spectrometry data. We perform a new evaluation of the fission product yields that is planned for ENDF/B-VII.1. Because the measurement database for some of the FPs is small—especially for 147Nd and 99Mo—we use a meta-analysis that incorporates insights from other accurately-measured benchmark FP data. The %-relative changes compared to ENDF/B-VI are small for some FPs (less than 1% for 95Zr, 140Ba, 144Ce), but are larger for 99Mo (3%) and 147Nd (5%). We suggest an incident neutron energy dependence to the 147Nd fission product yield that accounts for observed differences in the FPY at a few-hundred keV average energy in fast reactors versus measurements made at higher average energies.

  1. Yields of fission products from various uranium and thorium targets

    Energy Technology Data Exchange (ETDEWEB)

    Kronenberg, A.; Spejewski, E.H.; Mervin, B.; Jost, C.; Carter, H.K. [Oak Ridge Associated Universities, Oak Ridge, TN 37831 (United States); Stracener, D.W. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Greene, J.P. [Argonne National Laboratory, Argonne, IL 60439 (United States)], E-mail: greene@anl.gov; Nolen, J.A. [Argonne National Laboratory, Argonne, IL 60439 (United States); Talbert, W.L. [TechSource, Inc., Santa Fe, NM 87501 (United States)

    2008-10-15

    Yield measurements from proton-induced fission have been performed on a number of actinide targets, both Th and U, at the on-line test facility at Oak Ridge National Laboratory. The results are discussed with a focus on the production process and physical and chemical properties of the targets.

  2. Yields of Fission Products from Various Uranium and Thorium Targets

    Energy Technology Data Exchange (ETDEWEB)

    Kronenberg, Andreas [Oak Ridge Associated Universities (ORAU); Spejewski, Eugene H. [Oak Ridge Associated Universities (ORAU); Mervin, Brenden T. [Oak Ridge Associated Universities (ORAU); Jost, Cara [Oak Ridge Associated Universities (ORAU); Carter, H Kennon [Oak Ridge Associated Universities (ORAU); Stracener, Daniel W [ORNL; Greene, John P. [Argonne National Laboratory (ANL); Nolen, Jerry A. [Argonne National Laboratory (ANL); Talbert, Willard L. [TechSource, Inc.

    2008-01-01

    Yield measurements from proton-induced fission have been performed on a number of actinide targets, both Th and U, at the on-line test facility at Oak Ridge National Laboratory. The results are discussed with a focus on the production process and physical and chemical properties of the targets.

  3. Yields of fission products from various uranium and thorium targets.

    Energy Technology Data Exchange (ETDEWEB)

    Kronenberg, A.; Spejewski, E. H.; Mervin, B.; Jost, C.; Carter, H. K.; Stracener, D. W.; Greene, J. P.; Nolen, J. A.; Talbert, W. L.; Physics; Oak Ridge Associated Univ.; ORNL; TechSource, Inc.

    2008-10-31

    Yield measurements from proton-induced fission have been performed on a number of actinide targets, both Th and U, at the on-line test facility at Oak Ridge National Laboratory. The results are discussed with a focus on the production process and physical and chemical properties of the targets.

  4. Report on simulation of fission gas and fission product diffusion in UO2

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Anders David [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Perriot, Romain Thibault [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Pastore, Giovanni [Idaho National Lab. (INL), Idaho Falls, ID (United States). Fuel Modeling and Simulation Dept.; Tonks, Michael R. [Idaho National Lab. (INL), Idaho Falls, ID (United States). Fuel Modeling and Simulation Dept.; Cooper, Michael William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Liu, Xiang-Yang [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Goyal, Anuj [Univ. of Florida, Gainesville, FL (United States). Dept. of Materials Science and Engineering; Uberuaga, Blas P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Stanek, Christopher Richard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division

    2016-07-22

    In UO2 nuclear fuel, the retention and release of fission gas atoms such as xenon (Xe) are important for nuclear fuel performance by, for example, reducing the fuel thermal conductivity, causing fuel swelling that leads to mechanical interaction with the clad, increasing the plenum pressure and reducing the fuel–clad gap thermal conductivity. We use multi-­scale simulations to determine fission gas diffusion mechanisms as well as the corresponding rates in UO2 under both intrinsic and irradiation conditions. In addition to Xe and Kr, the fission products Zr, Ru, Ce, Y, La, Sr and Ba have been investigated. Density functional theory (DFT) calculations are used to study formation, binding and migration energies of small clusters of Xe atoms and vacancies. Empirical potential calculations enable us to determine the corresponding entropies and attempt frequencies for migration as well as investigate the properties of large clusters or small fission gas bubbles. A continuum reaction-­diffusion model is developed for Xe and point defects based on the mechanisms and rates obtained from atomistic simulations. Effective fission gas diffusivities are then obtained by solving this set of equations for different chemical and irradiation conditions using the MARMOT phase field code. The predictions are compared to available experimental data. The importance of the large XeU3O cluster (a Xe atom in a uranium + oxygen vacancy trap site with two bound uranium vacancies) is emphasized, which is a consequence of its high mobility and high binding energy. We find that the XeU3O cluster gives Xe diffusion coefficients that are higher for intrinsic conditions than under irradiation over a wide range of temperatures. Under irradiation the fast-­moving XeU3O cluster recombines quickly with irradiation induced interstitial U ions, while this mechanism is less important for intrinsic conditions. The net result is higher

  5. Report on simulation of fission gas and fission product diffusion in UO2

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Anders David [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Perriot, Romain Thibault [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Pastore, Giovanni [Idaho National Lab. (INL), Idaho Falls, ID (United States). Fuel Modeling and Simulation Dept.; Tonks, Michael R. [Idaho National Lab. (INL), Idaho Falls, ID (United States). Fuel Modeling and Simulation Dept.; Cooper, Michael William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Liu, Xiang-Yang [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Goyal, Anuj [Univ. of Florida, Gainesville, FL (United States). Dept. of Materials Science and Engineering; Uberuaga, Blas P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Stanek, Christopher Richard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division

    2016-07-22

    In UO2 nuclear fuel, the retention and release of fission gas atoms such as xenon (Xe) are important for nuclear fuel performance by, for example, reducing the fuel thermal conductivity, causing fuel swelling that leads to mechanical interaction with the clad, increasing the plenum pressure and reducing the fuel–clad gap thermal conductivity. We use multi-­scale simulations to determine fission gas diffusion mechanisms as well as the corresponding rates in UO2 under both intrinsic and irradiation conditions. In addition to Xe and Kr, the fission products Zr, Ru, Ce, Y, La, Sr and Ba have been investigated. Density functional theory (DFT) calculations are used to study formation, binding and migration energies of small clusters of Xe atoms and vacancies. Empirical potential calculations enable us to determine the corresponding entropies and attempt frequencies for migration as well as investigate the properties of large clusters or small fission gas bubbles. A continuum reaction-­diffusion model is developed for Xe and point defects based on the mechanisms and rates obtained from atomistic simulations. Effective fission gas diffusivities are then obtained by solving this set of equations for different chemical and irradiation conditions using the MARMOT phase field code. The predictions are compared to available experimental data. The importance of the large XeU3O cluster (a Xe atom in a uranium + oxygen vacancy trap site with two bound uranium vacancies) is emphasized, which is a consequence of its high mobility and high binding energy. We find that the XeU3O cluster gives Xe diffusion coefficients that are higher for intrinsic conditions than under irradiation over a wide range of temperatures. Under irradiation the fast-­moving XeU3O cluster recombines quickly with irradiation-induced interstitial U ions, while this mechanism is less important for intrinsic conditions. The net result is higher

  6. Fission Product Yield Study of 235U, 238U and 239Pu Using Dual-Fission Ionization Chambers

    Science.gov (United States)

    Bhatia, C.; Fallin, B.; Howell, C.; Tornow, W.; Gooden, M.; Kelley, J.; Arnold, C.; Bond, E.; Bredeweg, T.; Fowler, M.; Moody, W.; Rundberg, R.; Rusev, G.; Vieira, D.; Wilhelmy, J.; Becker, J.; Macri, R.; Ryan, C.; Sheets, S.; Stoyer, M.; Tonchev, A.

    2014-05-01

    To resolve long-standing differences between LANL and LLNL regarding the correct fission basis for analysis of nuclear test data [M.B. Chadwick et al., Nucl. Data Sheets 111, 2891 (2010); H. Selby et al., Nucl. Data Sheets 111, 2891 (2010)], a collaboration between TUNL/LANL/LLNL has been established to perform high-precision measurements of neutron induced fission product yields. The main goal is to make a definitive statement about the energy dependence of the fission yields to an accuracy better than 2-3% between 1 and 15 MeV, where experimental data are very scarce. At TUNL, we have completed the design, fabrication and testing of three dual-fission chambers dedicated to 235U, 238U, and 239Pu. The dual-fission chambers were used to make measurements of the fission product activity relative to the total fission rate, as well as for high-precision absolute fission yield measurements. The activation method was employed, utilizing the mono-energetic neutron beams available at TUNL. Neutrons of 4.6, 9.0, and 14.5 MeV were produced via the 2H(d,n)3He reaction, and for neutrons at 14.8 MeV, the 3H(d,n)4He reaction was used. After activation, the induced γ-ray activity of the fission products was measured for two months using high-resolution HPGe detectors in a low-background environment. Results for the yield of seven fission fragments of 235U, 238U, and 239Pu and a comparison to available data at other energies are reported. For the first time results are available for neutron energies between 2 and 14 MeV.

  7. NEANDC specialists meeting on yields and decay data of fission product nuclides

    Energy Technology Data Exchange (ETDEWEB)

    Chrien, R.E.; Burrows, T.W. (eds.)

    1983-01-01

    Separate abstracts were prepared for the 29 papers presented. Workshop reports on decay heat, fission yields, beta- and gamma-ray spectroscopy, and delayed neutrons are included. An appendix contains a survey of the most recent compilations and evaluations containing fission product yield, fission product decay data, and delayed neutron yield information. (WHK)

  8. Molten salt extraction of transuranic and reactive fission products from used uranium oxide fuel

    Science.gov (United States)

    Herrmann, Steven Douglas

    2014-05-27

    Used uranium oxide fuel is detoxified by extracting transuranic and reactive fission products into molten salt. By contacting declad and crushed used uranium oxide fuel with a molten halide salt containing a minor fraction of the respective uranium trihalide, transuranic and reactive fission products partition from the fuel to the molten salt phase, while uranium oxide and non-reactive, or noble metal, fission products remain in an insoluble solid phase. The salt is then separated from the fuel via draining and distillation. By this method, the bulk of the decay heat, fission poisoning capacity, and radiotoxicity are removed from the used fuel. The remaining radioactivity from the noble metal fission products in the detoxified fuel is primarily limited to soft beta emitters. The extracted transuranic and reactive fission products are amenable to existing technologies for group uranium/transuranic product recovery and fission product immobilization in engineered waste forms.

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

    Science.gov (United States)

    Kaminski, Michael D.; Mertz, Carol J.

    2016-06-07

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

  10. Chemical state of fission products in irradiated UO 2

    Science.gov (United States)

    Imoto, S.

    1986-08-01

    The chemical state of fission products in irradiated UO 2 fuel has been estimated for FBR as well as LWR on the basis of equilibrium calculation with the SOLGASMIX-PV code. The system considered for the calculation is composed of a gas phase, a CaF 2 type oxide phase, three grey phases, a noble metal alloy, a mixed telluride phase and several other phases each consisting of single compound. The distribution of elements into these phases and the amount of chemical species in each phase at different temperatures are obtained as a function of oxygen potential for LWR and FBR. Changes of the chemical potential of the fuel-fission products system during burnup are also evaluated with particular attention to the difference between LWR and FBR. Some informations obtained by the calculation are compared with the results of post irradiation examination of UO 2 fuels.

  11. Measurements of actinide-fission product yields in Caliban and Prospero metallic core reactor fission neutron fields

    Energy Technology Data Exchange (ETDEWEB)

    Casoli, P.; Authier, N. [CEA, Centre de Valduc, 21120 Is-sur-Tille (France); Laurec, J.; Bauge, E.; Granier, T. [CEA, Centre DIF, 91297 Arpajon (France)

    2011-07-01

    In the 1970's and early 1980's, an experimental program was performed on the facilities of the CEA Valduc Research Center to measure several actinide-fission product yields. Experiments were, in particular, completed on the Caliban and Prospero metallic core reactors to study fission-neutron-induced reactions on {sup 233}U, {sup 235}U, and {sup 239}Pu. Thick actinide samples were irradiated and the number of nuclei of each fission product was determined by gamma spectrometry. Fission chambers were irradiated simultaneously to measure the numbers of fissions in thin deposits of the same actinides. The masses of the thick samples and the thin deposits were determined by mass spectrometry and alpha spectrometry. The results of these experiments will be fully presented in this paper for the first time. A description of the Caliban and Prospero reactors, their characteristics and performances, and explanations about the experimental approach will also be given in the article. A recent work has been completed to analyze and reinterpret these measurements and particularly to evaluate the associated uncertainties. In this context, calculations have also been carried out with the Monte Carlo transport code Tripoli-4, using the published benchmarked Caliban description and a three-dimensional model of Prospero, to determine the average neutron energy causing fission. Simulation results will be discussed in this paper. Finally, new fission yield measurements will be proposed on Caliban and Prospero reactors to strengthen the results of the first experiments. (authors)

  12. Uncertainties on decay heat power due to fission product data uncertainties; Incertitudes sur la puissance residuelle dues aux incertitudes sur les donnees de produits de fission

    Energy Technology Data Exchange (ETDEWEB)

    Rebah, J

    1998-08-01

    Following a reactor shutdown, after the fission process has completely faded out, a significant quantity of energy known as 'decay heat' continues to be generated in the core. The knowledge with a good precision of the decay heat released in a fuel after reactor shutdown is necessary for: residual heat removal for normal operation or emergency shutdown condition, the design of cooling systems and spent fuel handling. By the summation calculations method, the decay heat is equal to the sum of the energies released by individual fission products. Under taking into account all nuclides that contribute significantly to the total decay heat, the results from summation method are comparable with the measured ones. Without the complete covariance information of nuclear data, the published uncertainty analyses of fission products decay heat summation calculation give underestimated errors through the variance/covariance analysis in consideration of correlation between the basic nuclear data, we calculate in this work the uncertainties on the decay heat associated with the summation calculations. Contribution to the total error of decay heat comes from uncertainties in three terms: fission yields, half-lives and average beta and gamma decay energy. (author)

  13. RAPID QUANTITATION OF URANIUM FROM MIXED FISSION PRODUCT SAMPLES

    Energy Technology Data Exchange (ETDEWEB)

    Haney, Morgan M.; Seiner, Brienne N.; Finn, Erin C.; Friese, Judah I.

    2016-03-09

    Chemical similarities between U(VI) and Mo(VI) create challenges for separation and quantification of uranium from a mixed fission product sample. The purpose of this work was to demonstrate the feasibility of using Eichrom’s® UTEVA resin in addition to a tellurium spontaneous deposition to improve the quantitation of 235U using gamma spectroscopy. The optimized method demonstrated a consistent chemical yield of 74 ± 3 % for uranium. This procedure was evaluated using 1.41x1012 fissions produced from an irradiated HEU sample. The uranium was isotopically yielded by HPGe, and the minimum detectable activity (MDA) determined from the gamma spectra. The MDA for 235U, 237U, and 238U was reduced by a factor of two. The chemical isolation of uranium was successfully achieved in less than four hours, with a separation factor of 1.41x105 from molybdenum.

  14. Thermoradiation treatment of sewage sludge using reactor waste fission products

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, M. C.; Hagengruber, R. L.; Zuppero, A. C.

    1974-06-01

    The hazards to public health associated with the application of municipal sewage sludge to land usage are reviewed to establish the need for disinfection of sludge prior to its distribution as a fertilizer, especially in the production of food and fodder. The use of ionizing radiation in conjunction with mild heating is shown to be an effective disinfection treatment and an economical one when reactor waste fission products are utilized. A program for researching and experimental demonstration of the process on sludges is also outlined.

  15. Fission Product Separation from Pyrochemical Electrolyte by Cold Finger Melt Crystallization

    Energy Technology Data Exchange (ETDEWEB)

    Versey, Joshua R. [Univ. of Idaho, Moscow, ID (United States)

    2013-08-01

    This work contributes to the development of pyroprocessing technology as an economically viable means of separating used nuclear fuel from fission products and cladding materials. Electrolytic oxide reduction is used as a head-end step before electrorefining to reduce oxide fuel to metallic form. The electrolytic medium used in this technique is molten LiCl-Li2O. Groups I and II fission products, such as cesium (Cs) and strontium (Sr), have been shown to partition from the fuel into the molten LiCl-Li2O. Various approaches of separating these fission products from the salt have been investigated by different research groups. One promising approach is based on a layer crystallization method studied at the Korea Atomic Energy Research Institute (KAERI). Despite successful demonstration of this basic approach, there are questions that remain, especially concerning the development of economical and scalable operating parameters based on a comprehensive understanding of heat and mass transfer. This research explores these parameters through a series of experiments in which LiCl is purified, by concentrating CsCl in a liquid phase as purified LiCl is crystallized and removed via an argon-cooled cold finger.

  16. Fission product plateout/liftoff/washoff test plan. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Acharya, R.; Hanson, D.

    1988-05-01

    A test program is planned in the COMEDIE loop of the Commissariat a l`Energy Atomique (CEA), Grenoble, France, to generate integral test data for the validation of computer codes used to predict fission product transport and core corrosion in the Modular High Temperature Gas-Cooled Reactor (MHTGR). The inpile testing will be performed by the CEA under contract from the US Department of Energy (DOE); the contract will be administered by Oak Ridge National Laboratory (ORNL). The primary purpose of this test plan is to provide an overview of the proposed program in terms of the overall scope and schedule. 8 refs, 3 figs.

  17. Decay characteristics of fission products and summation calculation

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Tadashi [Faculty of Engineering, Musashi Institute of Technology, Tokyo (Japan)

    1999-02-01

    This paper reviews the decay characteristics of fission products on the viewpoint of summation calculation. The fission products (FPs) are accumulated in the operating power reactors. As they are neutron-rich at the time of scission, they undergo successive beta decays toward stable nuclides. To grasp the quantity of an arbitrary nuclide, fission yields, decay constants and blanching ratios of the nuclide in the same decay chain ( a mass chain of the fixed mass is sufficient) must be known. As a neutron capture increases the mass, and release of a delayed neutron decreases the mass, capture cross sections and delayed neutron emitting ratios are also required. If these values of all FP are known, the quantities such as time dependent decay heat and the delayed neutron fraction can be calculated by summation of the contribution of the nuclides. A computer code ORIGEN-2 is a typical example to compute these quantities. The more important than computer code is the data library for summation calculation which includes physical constants such as fission yields, decay constants, blanching ratio, beta and gamma energy emitted at a beta decay, delayed neutron emitting ratios, and neutron capture cross sections for more than 1000 FP nuclides. They are realized in JNDC FP Decay Data Library-Version 2 of Japan, JEF-2 by western European countries, and ENDF/B-VI of USA. The early versions (until early 80's) of these full-scale libraries showed worse agreement with experiment than the old libraries based on approximations and estimates. The application of the gross theory to beta-decay' to short-lived FPs could solve the problem. The above disagreement is explained by having dropped of high excitation levels of short lived daughter nuclides. This is called as Pandemonium Problem. The summation calculation for the gamma ray spectrum succeeded to predict the experimental value by correcting theoretical spectrum. However, there remains still an underestimate for cooling

  18. Airborne measurements of fission product fall-out

    Energy Technology Data Exchange (ETDEWEB)

    Hovgaard, J.; Korsbech, U.

    1992-12-01

    During 1993 the Danish Emergency Management Agency will install an airborne [gamma]-ray detector system for area survey of contamination with radioactive nuclides - primarily fission products that may be released during a heavy accident at a nuclear power plant or from accidents during transport of radioactive material. The equipment is based on 16 liter NaI(TI) crystals and multichannel analysers from Exploranium (Canada). A preliminary investigation of the possibilities for detection of low and high level contamination - and the problems that may be expected during use of the equipment, and during interpretation of the measured data, is described. Several days after reactor shut-down some of the nuclides can be identified directly from the measured spectrum, and contamination levels may be determined within a factor two. After several weeks, most fission products have decayed. Concentrations and exposure rates can be determined with increasing accuracy as time passes. Approximate calibration of the equipment for measurements of surface contamination and natural radioactivity can be performed in the laboratory. Further checks of equipment should include accurate measurements of the spectrum resolution. Detectors should be checked individually, and all together. Further control of dead time and pulse pile-up should be performed. Energy calibration, electronics performance and data equipment should be tested against results from the original calibration. (AB).

  19. Biological removal of cationic fission products from nuclear wastewater.

    Science.gov (United States)

    Ngwenya, N; Chirwa, E M N

    2011-01-01

    Nuclear energy is becoming a preferred energy source amidst rising concerns over the impacts of fossil fuel based energy on global warming and climate change. However, the radioactive waste generated during nuclear power generation contains harmful long-lived fission products such as strontium (Sr). In this study, cationic strontium uptake from solution by microbial cultures obtained from mine wastewater is evaluated. A high strontium removal capacity (q(max)) with maximum loading of 444 mg/g biomass was achieved by a mixed sulphate reducing bacteria (SRB) culture. Sr removal in SRB was facilitated by cell surface based electrostatic interactions with the formation of weak ionic bonds, as 68% of the adsorbed Sr(2+) was easily desorbed from the biomass in an ion exchange reaction with MgCl₂. To a lesser extent, precipitation reactions were also found to account for the removal of Sr from aqueous solution as about 3% of the sorbed Sr was precipitated due to the presence of chemical ligands while the remainder occurred as an immobile fraction. Further analysis of the Sr-loaded SRB biomass by scanning electron microscopy (SEM) coupled to energy dispersive X-ray (EDX) confirmed extracellular Sr(2+) precipitation as a result of chemical interaction. In summary, the obtained results demonstrate the prospects of using biological technologies for the remediation of industrial wastewaters contaminated by fission products.

  20. Immobilization of fission products in phosphate ceramic waste forms

    Energy Technology Data Exchange (ETDEWEB)

    Singh, D.; Wagh, A. [Argonne National Lab., IL (United States)

    1997-10-01

    Chemically bonded phosphate ceramics (CBPCs) have several advantages that make them ideal candidates for containing radioactive and hazardous wastes. In general, phosphates have high solid-solution capacities for incorporating radionuclides, as evidenced by several phosphates (e.g., monazites and apatites) that are natural analogs of radioactive and rare-earth elements. The phosphates have high radiation stability, are refractory, and will not degrade in the presence of internal heating by fission products. Dense and hard CBPCs can be fabricated inexpensively and at low temperature by acid-base reactions between an inorganic oxide/hydroxide powder and either phosphoric acid or an acid-phosphate solution. The resulting phosphates are extremely insoluble in aqueous media and have excellent long-term durability. CBPCs offer the dual stabilization mechanisms of chemical fixation and physical encapsulation, resulting in superior waste forms. The goal of this task is develop and demonstrate the feasibility of CBPCs for S/S of wastes containing fission products. The focus of this work is to develop a low-temperature CBPC immobilization system for eluted {sup 99}Tc wastes from sorption processes.

  1. Analysis of Fission Products on the AGR-1 Capsule Components

    Energy Technology Data Exchange (ETDEWEB)

    Paul A. Demkowicz; Jason M. Harp; Philip L. Winston; Scott A. Ploger

    2013-03-01

    The components of the AGR-1 irradiation capsules were analyzed to determine the retained inventory of fission products in order to determine the extent of in-pile fission product release from the fuel compacts. This includes analysis of (i) the metal capsule components, (ii) the graphite fuel holders, (iii) the graphite spacers, and (iv) the gas exit lines. The fission products most prevalent in the components were Ag-110m, Cs 134, Cs 137, Eu-154, and Sr 90, and the most common location was the metal capsule components and the graphite fuel holders. Gamma scanning of the graphite fuel holders was also performed to determine spatial distribution of Ag-110m and radiocesium. Silver was released from the fuel components in significant fractions. The total Ag-110m inventory found in the capsules ranged from 1.2×10 2 (Capsule 3) to 3.8×10 1 (Capsule 6). Ag-110m was not distributed evenly in the graphite fuel holders, but tended to concentrate at the axial ends of the graphite holders in Capsules 1 and 6 (located at the top and bottom of the test train) and near the axial center in Capsules 2, 3, and 5 (in the center of the test train). The Ag-110m further tended to be concentrated around fuel stacks 1 and 3, the two stacks facing the ATR reactor core and location of higher burnup, neutron fluence, and temperatures compared with Stack 2. Detailed correlation of silver release with fuel type and irradiation temperatures is problematic at the capsule level due to the large range of temperatures experienced by individual fuel compacts in each capsule. A comprehensive Ag 110m mass balance for the capsules was performed using measured inventories of individual compacts and the inventory on the capsule components. For most capsules, the mass balance was within 11% of the predicted inventory. The Ag-110m release from individual compacts often exhibited a very large range within a particular capsule.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-06-01

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

  3. First-principles study of the stability of fission products in uranium monocarbide

    Science.gov (United States)

    Bévillon, Émile; Ducher, Roland; Barrachin, Marc; Dubourg, Roland

    2012-07-01

    The incorporation and stability of fission products in uranium monocarbide are studied by means of Density Functional Theory using the generalized gradient approximation and projector-augmented waves method. The computations are performed considering incorporation sites of UC, such as the U, C and interstitial sites, and Schottky defects. The computed incorporation energies are discussed on the basis of the atomic size of the fission products, their chemical environment and the electronic structure. These energies show that all the studied fission products would preferentially occupy the U site. However, incorporation energies do not provide any further information on the fission product location in the case of unavailability of the sites which is why the concept of solution energies is also used. The solution energies obtained confirm that all the fission products are expected to be more stable on a U site of a single uranium vacancy or within a non-bound Schottky defect in equilibrium conditions.

  4. First-principles study of the stability of fission products in uranium monocarbide

    Energy Technology Data Exchange (ETDEWEB)

    Bevillon, Emile, E-mail: emile.bevillon@yahoo.fr [IRSN, SEMIC, DPAM, LETR, Centre de Cadarache, 13115 Saint Paul Lez Durance (France); Ducher, Roland; Barrachin, Marc; Dubourg, Roland [IRSN, SEMIC, DPAM, LETR, Centre de Cadarache, 13115 Saint Paul Lez Durance (France)

    2012-07-15

    The incorporation and stability of fission products in uranium monocarbide are studied by means of Density Functional Theory using the generalized gradient approximation and projector-augmented waves method. The computations are performed considering incorporation sites of UC, such as the U, C and interstitial sites, and Schottky defects. The computed incorporation energies are discussed on the basis of the atomic size of the fission products, their chemical environment and the electronic structure. These energies show that all the studied fission products would preferentially occupy the U site. However, incorporation energies do not provide any further information on the fission product location in the case of unavailability of the sites which is why the concept of solution energies is also used. The solution energies obtained confirm that all the fission products are expected to be more stable on a U site of a single uranium vacancy or within a non-bound Schottky defect in equilibrium conditions.

  5. Fission product concentration evolution in sodium pool following a fuel subassembly failure in an LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.; Velusamy, K.; Selvaraj, P.; Kasinathan, N.; Chellapandi, P.; Chetal, S.; Bhoje, S. [Indira Gandhi Center for Atomic Research, Kalpakkam (India)

    2003-07-01

    During a fuel element failure in a liquid metal cooled fast breeder reactor, the fission products originating from the failed pins mix into the sodium pool. Delayed Neutron Detectors (DND) are provided in the sodium pool to detect such failures by way of detection of delayed neutrons emitted by the fission products. The transient evolution of fission product concentration is governed by the sodium flow distribution in the pool. Transient hydraulic analysis has been carried out using the CFD code PHOENICS to estimate fission product concentration evolution in hot pool. k- {epsilon} turbulence model and zero laminar diffusivity for the fission product concentration have been considered in the analysis. Times at which the failures of various fuel subassemblies (SA) are detected by the DND are obtained. It has been found that in order to effectively detect the failure of every fuel SA, a minimum of 8 DND in hot pool are essential.

  6. Radioanalytical determination of actinides and fission products in Belarus soils.

    Science.gov (United States)

    Michel, H; Gasparro, J; Barci-Funel, G; Dalmasso, J; Ardisson, G; Sharovarov, G

    1999-04-01

    Alpha emitting actinides such as plutonium, americium or curium were measured by alpha-spectrometry after radiochemical separation. The short range of alpha-particles within matter requires, after a pre-concentration process, a succession of isolation and purification steps based on the valence states modification of the researched elements. For counting, actinides were electrodeposited in view to obtain the mass-less source necessary to avoid self-absorption of the emitted radiations. Activity concentrations of gamma-emitting fission products were calculated after measurement with high purity germanium detectors (HPGe). These different methods were used to analyse soils sampled in the Republic of Belarus, not far from the Chernobyl nuclear plant.

  7. Neutron Cross Section Covariances for Structural Materials and Fission Products

    Science.gov (United States)

    Hoblit, S.; Cho, Y.-S.; Herman, M.; Mattoon, C. M.; Mughabghab, S. F.; Obložinský, P.; Pigni, M. T.; Sonzogni, A. A.

    2011-12-01

    We describe neutron cross section covariances for 78 structural materials and fission products produced for the new US evaluated nuclear reaction library ENDF/B-VII.1. Neutron incident energies cover full range from 10 eV to 20 MeV and covariances are primarily provided for capture, elastic and inelastic scattering as well as (n,2n). The list of materials follows priorities defined by the Advanced Fuel Cycle Initiative, the major application being data adjustment for advanced fast reactor systems. Thus, in addition to 28 structural materials and 49 fission products, the list includes also 23Na which is important fast reactor coolant. Due to extensive amount of materials, we adopted a variety of methodologies depending on the priority of a specific material. In the resolved resonance region we primarily used resonance parameter uncertainties given in Atlas of Neutron Resonances and either applied the kernel approximation to propagate these uncertainties into cross section uncertainties or resorted to simplified estimates based on integral quantities. For several priority materials we adopted MF32 covariances produced by SAMMY at ORNL, modified by us by adding MF33 covariances to account for systematic uncertainties. In the fast neutron region we resorted to three methods. The most sophisticated was EMPIRE-KALMAN method which combines experimental data from EXFOR library with nuclear reaction modeling and least-squares fitting. The two other methods used simplified estimates, either based on the propagation of nuclear reaction model parameter uncertainties or on a dispersion analysis of central cross section values in recent evaluated data files. All covariances were subject to quality assurance procedures adopted recently by CSEWG. In addition, tools were developed to allow inspection of processed covariances and computed integral quantities, and for comparing these values to data from the Atlas and the astrophysics database KADoNiS.

  8. Neutron Cross Section Covariances for Structural Materials and Fission Products

    Energy Technology Data Exchange (ETDEWEB)

    Hoblit, S.; Hoblit,S.; Cho,Y.-S.; Herman,M.; Mattoon,C.M.; Mughabghab,S.F.; Oblozinsky,P.; Pigni,M.T.; Sonzogni,A.A.

    2011-12-01

    We describe neutron cross section covariances for 78 structural materials and fission products produced for the new US evaluated nuclear reaction library ENDF/B-VII.1. Neutron incident energies cover full range from 10{sup -5} eV to 20 MeV and covariances are primarily provided for capture, elastic and inelastic scattering as well as (n,2n). The list of materials follows priorities defined by the Advanced Fuel Cycle Initiative, the major application being data adjustment for advanced fast reactor systems. Thus, in addition to 28 structural materials and 49 fission products, the list includes also {sup 23}Na which is important fast reactor coolant. Due to extensive amount of materials, we adopted a variety of methodologies depending on the priority of a specific material. In the resolved resonance region we primarily used resonance parameter uncertainties given in Atlas of Neutron Resonances and either applied the kernel approximation to propagate these uncertainties into cross section uncertainties or resorted to simplified estimates based on integral quantities. For several priority materials we adopted MF32 covariances produced by SAMMY at ORNL, modified by us by adding MF33 covariances to account for systematic uncertainties. In the fast neutron region we resorted to three methods. The most sophisticated was EMPIRE-KALMAN method which combines experimental data from EXFOR library with nuclear reaction modeling and least-squares fitting. The two other methods used simplified estimates, either based on the propagation of nuclear reaction model parameter uncertainties or on a dispersion analysis of central cross section values in recent evaluated data files. All covariances were subject to quality assurance procedures adopted recently by CSEWG. In addition, tools were developed to allow inspection of processed covariances and computed integral quantities, and for comparing these values to data from the Atlas and the astrophysics database KADoNiS.

  9. Advanced model for the prediction of the neutron-rich fission product yields

    Directory of Open Access Journals (Sweden)

    Rubchenya V. A.

    2013-12-01

    Full Text Available The consistent models for the description of the independent fission product formation cross sections in the spontaneous fission and in the neutron and proton induced fission at the energies up to 100 MeV is developed. This model is a combination of new version of the two-component exciton model and a time-dependent statistical model for fusion-fission process with inclusion of dynamical effects for accurate calculations of nucleon composition and excitation energy of the fissioning nucleus at the scission point. For each member of the compound nucleus ensemble at the scission point, the primary fission fragment characteristics: kinetic and excitation energies and their yields are calculated using the scission-point fission model with inclusion of the nuclear shell and pairing effects, and multimodal approach. The charge distribution of the primary fragment isobaric chains was considered as a result of the frozen quantal fluctuations of the isovector nuclear matter density at the scission point with the finite neck radius. Model parameters were obtained from the comparison of the predicted independent product fission yields with the experimental results and with the neutron-rich fission product data measured with a Penning trap at the Accelerator Laboratory of the University of Jyväskylä (JYFLTRAP.

  10. Determining isotopic distributions of fission products with a penning trap

    Energy Technology Data Exchange (ETDEWEB)

    Penttilae, H.; Karvonen, P.; Eronen, T.; Elomaa, V.V.; Hager, U.; Hakala, J.; Jokinen, A.; Kankainen, A.; Moore, I.D.; Peraejaervi, K.; Rahaman, S.; Rinta-Antila, S.; Saastamoinen, A.; Sonoda, T.; Aeystoe, J. [University of Jyvaeskylae, Department of Physics, Jyvaeskylae (Finland); Rubchenya, V. [University of Jyvaeskylae, Department of Physics, Jyvaeskylae (Finland); V.G. Khlopin Radium Institute, St. Petersburg (Russian Federation)

    2010-04-15

    A novel method to determine independent yields in particle-induced fission employing the ion guide technique and ion counting after a Penning trap has been developed. The method takes advantage of the fact that a Penning trap can be used as a precision mass filter, which allows an unambiguous identification of the fission fragments. The method was tested with 25MeV and 50MeV proton-induced fission of {sup 238}U. The data is internally reproducible with an accuracy of a few per cent. A satisfactory agreement was obtained with older ion guide yield measurements in 25MeV proton-induced fission. The results for Rb and Cs yields in 50MeV proton-induced fission agree with previous measurements performed at an isotope separator equipped with a chemically selective ion source. (orig.)

  11. High-Resolution Correlated Fission Product Measurements of 235U (nth , f) with SPIDER

    Science.gov (United States)

    Shields, Dan; Spider Team

    2015-10-01

    The SPIDER detector (SPectrometer for Ion DEtermination in fission Research) has obtained high-resolution, moderate-efficiency, correlated fission product data needed for many applications including the modeling of next generation nuclear reactors, stockpile stewardship, and the fundamental understanding of the fission process. SPIDER simultaneously measures velocity and energy of both fission products to calculate fission product yields (FPYs), neutron multiplicity (ν), and total kinetic energy (TKE). These data will be some of the first of their kind available to nuclear data evaluations. An overview of the SPIDER detector, analytical method, and preliminary results for 235U (nth , f) will be presented. LA-UR-15-20130 This work benefited from the use of the LANSCE accelerator facility and was performed under the auspices of the US Department of Energy by Los Alamos Security, LLC under Contract DE-AC52-06NA25396.

  12. A proposed standard on medical isotope production in fission reactors

    Energy Technology Data Exchange (ETDEWEB)

    Schenter, R. E. [Smart Bullets Inc., 2521 SW Luradel Street, Portland, OR 97219 (United States); Brown, G. J. [Ozarks Medical Center, Cancer Treatment Center, Shaw Medical Building, 1111 Kentucky Avenue, West Plains, MO 65775 (United States); Holden, C. S. [Thorenco LLC, 369 Pine Street, San Francisco, CA 94104 (United States)

    2006-07-01

    Authors Robert E. Sehenter, Garry Brown and Charles S. Holden argue that a Standard for 'Medical Isotope Production' is needed. Medical isotopes are becoming major components of application for the diagnosis and treatment of all the major diseases including all forms of cancer, heart disease, arthritis, Alzheimer's, among others. Current nuclear data to perform calculations is incomplete, dated or imprecise or otherwise flawed for many isotopes that could have significant applications in medicine. Improved data files will assist computational analyses to design means and methods for improved isotope production techniques in the fission reactor systems. Initial focus of the Standard is expected to be on neutron cross section and branching data for both fast and thermal reactor systems. Evaluated and reviewed tables giving thermal capture cross sections and resonance integrals for the major target and product medical isotopes would be the expected 'first start' for the 'Standard Working Group'. (authors)

  13. Evaluation of Neutron Induced Reactions for 32 Fission Products

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyeong Il

    2007-02-15

    Neutron cross sections for 32 fission products were evaluated in the neutron-incident energy range from 10{sup -5} eV to 20 MeV. The list of fission products consists of the priority materials for several applications, extended to cover complete isotopic chains for three elements. The full list includes 8 individual isotopes, {sup 95}Mo, {sup 101}Ru, {sup 103}Rh, {sup 105}Pd, {sup 109}Ag, {sup 131}Xe, {sup 133}Cs, {sup 141}Pr, and 24 isotopes in complete isotopic chains for Nd (8), Sm (9) and Dy (7). Our evaluation methodology covers both the low energy region and the fast neutron region.In the low energy region, our evaluations are based on the latest data published in the Atlas of Neutron Resonances. This resource was used to infer both the thermal values and the resolved resonance parameters that were validated against the capture resonance integrals. In the unresolved resonance region we performed the additional evaluation by using the averages of the resolved resonances and adjusting them to the experimental data.In the fast neutron region our evaluations are based on the nuclear reaction model code EMPIRE-2.19 validated against the experimental data. EMPIRE is the modular system of codes consisting of many nuclear reaction models, including the spherical and deformed Optical Model, Hauser-Feshbach theory with the width fluctuation correction and complete gamma-ray emission cascade, DWBA, Multi-step Direct and Multi-step Compound models, and several versions of the phenomenological preequilibrium models. The code is equipped with a power full GUI, allowing an easy access to support libraries such as RIPL and CSISRS, the graphical package, as well the utility codes for formatting and checking. In general, in our calculations we used the Reference Input Parameter Library, RIPL, for the initial set model parameters. These parameters were properly adjusted to reproduce the available experimental data taken from the CSISRS library. Our evaluations cover cross

  14. Fabrication of atomized uranium dispersion targets for fission mo production

    Energy Technology Data Exchange (ETDEWEB)

    Sim, Moonsoo; Ryu, Ho Jin; Park, Jong Man; Kim, Chang Kyu; Lee, Jong Hyeon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-10-15

    Among radioisotopes for medical diagnosis, Tc-99m is most widely used. Mo-99 produced from nuclear fission of uranium in research reactors is the key radioisotopes for Tc-99m generators. Generally, major producers of Mo-99 still use targets containing highly enriched uranium (HEU). However, the international non-proliferation policy emphasizes the minimization of the use of HEU in medical radioisotopes production nowadays. Therefore, low enriched uranium (LEU) targets have been developed by casting and crushing of UAl{sub 2} compounds. The UAl{sub 2} particle dispersed target has a lower U-235 density when compared to HEU targets. In order to improve the low production efficiency of LEU targets, target designers try to develop high uranium density targets with LEU. KAERI has proposed that high density uranium alloys, instead of UAl{sub 2}, can be used as dispersing particles in an aluminum matrix. While it is very difficult to fabricate uranium alloys powder by grinding or crushing, spherical powder of uranium alloys can be produced easily by centrifugal atomization. Mini-size targets with 3, 6, and 9 g-U/cc were fabricated in this study to investigate the feasibility of high density targets with atomized uranium particles. The microstructural changes after thermal treatments were observed to analyze the interaction behavior of uranium particles and aluminum matrix.

  15. Radiation Damage and Fission Product Release in Zirconium Nitride

    Energy Technology Data Exchange (ETDEWEB)

    Egeland, Gerald W. [New Mexico Inst. of Mining and Technology, Socorro, NM (United States)

    2005-08-29

    Zirconium nitride is a material of interest to the AFCI program due to some of its particular properties, such as its high melting point, strength and thermal conductivity. It is to be used as an inert matrix or diluent with a nuclear fuel based on transuranics. As such, it must sustain not only high temperatures, but also continuous irradiation from fission and decay products. This study addresses the issues of irradiation damage and fission product retention in zirconium nitride through an assessment of defects that are produced, how they react, and how predictions can be made as to the overall lifespan of the complete nuclear fuel package. Ion irradiation experiments are a standard method for producing radiation damage to a surface for observation. Cryogenic irradiations are performed to produce the maximum accumulation of defects, while elevated temperature irradiations may be used to allow defects to migrate and react to form clusters and loops. Cross-sectional transmission electron microscopy and grazing-incidence x-ray diffractometry were used in evaluating the effects that irradiation has on the crystal structure and microstructure of the material. Other techniques were employed to evaluate physical effects, such as nanoindentation and helium release measurements. Results of the irradiations showed that, at cryogenic temperatures, ZrN withstood over 200 displacements per atom without amorphization. No significant change to the lattice or microstructure was observed. At elevated temperatures, the large amount of damage showed mobility, but did not anneal significantly. Defect clustering was possibly observed, yet the size was too small to evaluate, and bubble formation was not observed. Defects, specifically nitrogen vacancies, affect the mechanical behavior of ZrN dramatically. Current and previous work on dislocations shows a distinct change in slip plane, which is evidence of the bonding characteristics. The stacking-fault energy changes dramatically with

  16. Background and Derivation of ANS-5.4 Standard Fission Product Release Model

    Energy Technology Data Exchange (ETDEWEB)

    Beyer, Carl E.; Turnbull, Andrew J.

    2010-01-29

    This background report describes the technical basis for the newly proposed American Nuclear Society (ANS) 5.4 standard, Methods for Calculating the Fractional Release of Volatile Fission Products from Oxide Fuels. The proposed ANS 5.4 standard provides a methodology for determining the radioactive fission product releases from the fuel for use in assessing radiological consequences of postulated accidents that do not involve abrupt power transients. When coupled with isotopic yields, this method establishes the 'gap activity,' which is the inventory of volatile fission products that are released from the fuel rod if the cladding are breached.

  17. TMI-2 (Three Mile Island) fission product inventory program: FY-85 status report

    Energy Technology Data Exchange (ETDEWEB)

    Langer, S; Croney, S T; Akers, D W; Russell, M L

    1986-11-01

    This report presents the status of the TMI-2 fission product inventory program through May 1985. The fission product inventory program is an assessment of the location of fission products distributed in the plant as a result of the TMI-2 accident. Included in this report are principal results of samples from the reactor building where most of the mobile fission products (i.e., radiocesium and iodine) are expected to be found. The data are now complete enough for most reactor components; therefore, it is possible to direct the balance of the examination and sampling program to areas and components where it is likely to be most productive. Those areas are the reactor core and the reactor building basement, with emphasis on the currently unsampled portions of the core.

  18. Fission products from the damaged Fukushima reactor observed in Hungary.

    Science.gov (United States)

    Bihari, Árpád; Dezső, Zoltán; Bujtás, Tibor; Manga, László; Lencsés, András; Dombóvári, Péter; Csige, István; Ranga, Tibor; Mogyorósi, Magdolna; Veres, Mihály

    2014-01-01

    Fission products, especially (131)I, (134)Cs and (137)Cs, from the damaged Fukushima Dai-ichi nuclear power plant (NPP) were detected in many places worldwide shortly after the accident caused by natural disaster. To observe the spatial and temporal variation of these isotopes in Hungary, aerosol samples were collected at five locations from late March to early May 2011: Institute of Nuclear Research, Hungarian Academy of Sciences (ATOMKI, Debrecen, East Hungary), Paks NPP (Paks, South-Central Hungary) as well as at the vicinity of Aggtelek (Northeast Hungary), Tapolca (West Hungary) and Bátaapáti (Southwest Hungary) settlements. In addition to the aerosol samples, dry/wet fallout samples were collected at ATOMKI, and airborne elemental iodine and organic iodide samples were collected at Paks NPP. The peak in the activity concentration of airborne (131)I was observed around 30 March (1-3 mBq m(-3) both in aerosol samples and gaseous iodine traps) with a slow decline afterwards. Aerosol samples of several hundred cubic metres of air showed (134)Cs and (137)Cs in detectable amounts along with (131)I. The decay-corrected inventory of (131)I fallout at ATOMKI was 2.1±0.1 Bq m(-2) at maximum in the observation period. Dose-rate contribution calculations show that the radiological impact of this event at Hungarian locations was of no considerable concern.

  19. Fission-Product Development Laboratory cell-decommissioning project plan

    Energy Technology Data Exchange (ETDEWEB)

    Myrick, T.E.; Schaich, R.W.; Williams, F.V.

    1983-08-01

    The Fission Product Development Laboratory (FPDL) at Oak Ridge National Laboratory (ORNL) was a full-scale processing facility for separating megacurie quantities of /sup 90/Sr, /sup 137/Cs, and /sup 144/Ce for a variety of source applications, operating at full capacity from 1958 to 1975. Since facility shutdown, the inactive portions of the FPDL have been maintained in a protective storage mode as part of the ORNL Surplus Facilities Management Program (SFMP). Due to the significant radio-nuclide inventory remaining in the facility, the high surveillance and maintenance costs necessary to assure radionuclide containment, and the potential for reuse of the facility by other programs, the decommissioning of the inactive portions of the FPDL has been given a high priority by the SFMP. In response to this program direction, plans are being made for initiation of these activities in late FY 1983. This project plan has been prepared to satisfy the program documentation requirements for SFMP project planning. The plan outlines the scope of the proposed effort, describes the proposed methods of project accomplishment, and provides estimates of the project resource needs and schedule.

  20. Prompt γ-ray production in neutron-induced fission of 239Pu

    Science.gov (United States)

    Ullmann, J. L.; Bond, E. M.; Bredeweg, T. A.; Couture, A.; Haight, R. C.; Jandel, M.; Kawano, T.; Lee, H. Y.; O'Donnell, J. M.; Hayes, A. C.; Stetcu, I.; Taddeucci, T. N.; Talou, P.; Vieira, D. J.; Wilhelmy, J. B.; Becker, J. A.; Chyzh, A.; Gostic, J.; Henderson, R.; Kwan, E.; Wu, C. Y.

    2013-04-01

    Background: The prompt gamma-ray spectrum from fission is important for understanding the physics of nuclear fission, and also in applications involving fission. Relatively few measurements of the prompt gamma spectrum from 239Pu(n,f) have been published.Purpose: This experiment measured the multiplicity, individual gamma energy spectrum, and total gamma energy spectrum of prompt fission gamma rays from 239Pu(n,f) in the neutron energy range from thermal to 30 keV, to test models of fission and to provide information for applications.Method: Gamma rays from neutron-induced fission of 239Pu were measured using the DANCE gamma-ray calorimeter. Fission events were tagged by detecting fission products in a parallel-plate avalanche counter in the center of DANCE. The measurements were corrected for detector response using a geant4 model of DANCE. A detailed analysis for the gamma rays from the 1+ resonance complex at 10.93 eV is presented.Results: A six-parameter analytical parametrization of the fission gamma-ray spectrum was obtained. A Monte Carlo Hauser-Feshbach calculation provided good general agreement with the data, but some differences remain to be resolved.Conclusions: An analytic parametrization can be made of the gamma-ray multiplicity, energy distribution, and total-energy distribution for the prompt gamma rays following neutron-induced fission of 239Pu. This parametrization may be useful for applications. Modern Monte Carlo Hauser-Feshbach calculations can do a good job of calculating the fission gamma-ray emission spectrum, although some details remain to be understood.

  1. HTGR fuels and core development program. Quarterly progress report for the period ending November 30, 1976. [Graphite and fuel irradiations; fission product release

    Energy Technology Data Exchange (ETDEWEB)

    1976-12-27

    The work reported includes studies of reactions between core materials and coolant impurities, basic fission product transport mechanisms, core graphite development and testing, the development and testing of recyclable fuel systems, and physics and fuel management studies. Materials studies include irradiation capsule tests of both fuel and graphite. Experimental procedures and results are discussed and the data are presented in tables, graphs, and photographs.

  2. HTGR Fuels and Core Development Program. Quarterly progress report for the period ending August 31, 1977. [Graphite and fuel irradiation; fission product release

    Energy Technology Data Exchange (ETDEWEB)

    1977-09-01

    The work reported includes studies of reactions between core materials and coolant impurities, basic fission product transport mechanisms, core graphite development and testing, the development and testing of recyclable fuel systems, and physics and fuel management studies. Materials studies include irradiation capsule tests of both fuel and graphite. Experimental procedures and results are discussed and data are presented.

  3. HTGR fuels and core development program. Quarterly progress report for the period ending November 30, 1977. [Graphite and fuel irradiation; fission product release

    Energy Technology Data Exchange (ETDEWEB)

    1977-12-01

    The work reported here includes studies of basic fission product transport mechanisms, core graphite development and testing, and the development and testing of recyclable fuel systems. Materials studied include irradiation capsule tests of both fuel and graphite. Experimental procedures and results are discussed and data are presented.

  4. Investigation of inconsistent ENDF/B-VII.1 independent and cumulative fission product yields with proposed revisions

    Energy Technology Data Exchange (ETDEWEB)

    Pigni, Marco T [ORNL; Francis, Matthew W [ORNL; Gauld, Ian C [ORNL

    2015-01-01

    A recent implementation of ENDF/B-VII. independent fission product yields and nuclear decay data identified inconsistencies in the data caused by the use of updated nuclear scheme in the decay sub-library that is not reflected in legacy fission product yield data. Recent changes in the decay data sub-library, particularly the delayed neutron branching fractions, result in calculated fission product concentrations that are incompatible with the cumulative fission yields in the library, and also with experimental measurements. A comprehensive set of independent fission product yields was generated for thermal and fission spectrum neutron induced fission for 235,238U and 239,241Pu in order to provide a preliminary assessment of the updated fission product yield data consistency. These updated independent fission product yields were utilized in the ORIGEN code to evaluate the calculated fission product inventories with experimentally measured inventories, with particular attention given to the noble gases. An important outcome of this work is the development of fission product yield covariance data necessary for fission product uncertainty quantification. The evaluation methodology combines a sequential Bayesian method to guarantee consistency between independent and cumulative yields along with the physical constraints on the independent yields. This work was motivated to improve the performance of the ENDF/B-VII.1 library in the case of stable and long-lived cumulative yields due to the inconsistency of ENDF/B-VII.1 fission p;roduct yield and decay data sub-libraries. The revised fission product yields and the new covariance data are proposed as a revision to the fission yield data currently in ENDF/B-VII.1.

  5. Fission product inventory calculation by a CASMO/ORIGEN coupling program

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Do Heon; Kim, Jong Kyung [Hanyang University, Seoul (Korea, Republic of); Choi, Hang Bok; Roh, Gyu Hong; Jung, In Ha [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1997-12-31

    A CASMO/ORIGEN coupling utility program was developed to predict the composition of all the fission products in spent PWR fuels. The coupling program reads the CASMO output file, modifies the ORIGEN cross section library and reconstructs the ORIGEN input file at each depletion step. In ORIGEN, the burnup equation is solved for actinides and fission products based on the fission reaction rates and depletion flux of CASMO. A sample calculation has been performed using a 14 x 14 PWR fuel assembly and the results are given in this paper. 3 refs., 1 fig., 1 tab. (Author)

  6. Determination of {sup 140}La fission product interference factor for INAA

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro Jr, Iberê S.; Genezini, Frederico A.; Saiki, Mitiko; Zahn, Guilherme S. [Instituto de Pesquisas Energéticas e Nucleares, IPEN/CNEN-SP, São Paulo - SP (Brazil)

    2014-11-11

    Instrumental Neutron Activation Analysis (INAA) is a technique widely used to determine the concentration of several elements in several kinds of matrices. However if the sample of interest has higher relative uranium concentration the obtained results can be interfered by the uranium fission products. One of these cases that is affected by interference due to U fission is the {sup 140}La, because this radioisotope used in INAA for the determination of concentration the La is also produced by the {sup −}β of {sup 140}Ba, an uranium fission product. The {sup 140}La interference factor was studied in this work and a factor to describe its time dependence was obtained.

  7. The LANL C-NR counting room and fission product yields

    Energy Technology Data Exchange (ETDEWEB)

    Jackman, Kevin Richard [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

    2015-09-21

    This PowerPoint presentation focused on the following areas: LANL C-NR counting room; Fission product yields; Los Alamos Neutron wheel experiments; Recent experiments ad NCERC; and Post-detonation nuclear forensics

  8. Results of fission products β decay properties measurement performed with a total absorption spectrometer

    Directory of Open Access Journals (Sweden)

    Zakari-Issoufou A.-A.

    2014-03-01

    Full Text Available β-decay properties of fission products are very important for applied reactor physics, for instance to estimate the decay heat released immediately after the reactor shutdown and to estimate the ν¯$\\bar \

  9. Fission Product Yields of 233U, 235U, 238U and 239Pu in Fields of Thermal Neutrons, Fission Neutrons and 14.7-MeV Neutrons

    Science.gov (United States)

    Laurec, J.; Adam, A.; de Bruyne, T.; Bauge, E.; Granier, T.; Aupiais, J.; Bersillon, O.; Le Petit, G.; Authier, N.; Casoli, P.

    2010-12-01

    The yields of more than fifteen fission products have been carefully measured using radiochemical techniques, for 235U(n,f), 239Pu(n,f) in a thermal spectrum, for 233U(n,f), 235U(n,f), and 239Pu(n,f) reactions in a fission neutron spectrum, and for 233U(n,f), 235U(n,f), 238U(n,f), and 239Pu(n,f) for 14.7 MeV monoenergetic neutrons. Irradiations were performed at the EL3 reactor, at the Caliban and Prospero critical assemblies, and at the Lancelot electrostatic accelerator in CEA-Valduc. Fissions were counted in thin deposits using fission ionization chambers. The number of fission products of each species were measured by gamma spectrometry of co-located thick deposits.

  10. New Fission-Product Waste Forms: Development and Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Alexandra Navrotsky

    2010-07-30

    Research performed on the program “New Fission Product Waste Forms: Development and Characterization,” in the last three years has fulfilled the objectives of the proposal which were to 1) establish ceramic waste forms for disposing of Cs, Sr and minor actinides, 2) fully characterize the phase relationships, structures and thermodynamic and kinetic stabilities of promising waste forms, 3) establish a sound technical basis for understanding key waste form properties, such as melting temperatures and aqueous durability, based on an in-depth understanding of waste form structures and thermochemistry, and 4) establish synthesis, testing, scaleup and commercialization routes for wasteform implementation through out in-kind collaborations. In addition, since Cs and Sr form new elements by radioactive decay, the behavior and thermodynamics of waste forms containing different proportions of Cs, Sr and their decay products were discovered using non-radioactive analogues. Collaborations among researchers from three institutions, UC Davis, Sandia National Laboratories, and Shott Inc., were formed to perform the primary work on the program. The unique expertise of each of the members in the areas of waste form development, structure/property relationships, hydrothermal and high temperature synthesis, crystal/glass production, and thermochemistry was critical to program success. In addition, collaborations with the Brigham Young Univeristy, Ben Gurion University, and Los Alamos National Laboratory, were established for standard entropies of ceramic waste forms, sol-gel synthesis, and high temperature synthesis. This work has had a significant impact in a number of areas. First, the studies of the thermodynamic stability of the mineral analogues provided an important technical foundation for assessment the viability of multicomponent oxide phases for Cs and Sr removal. Moreover, the thermodynamic data discovered in this program established information on the reaction

  11. Towards a multiscale approach for assessing fission product behaviour in UN

    Energy Technology Data Exchange (ETDEWEB)

    Klipfel, M.; Di Marcello, V.; Schubert, A.; Laar, J. van de; Van Uffelen, P., E-mail: Paul.van-Uffelen@ec.europa.eu

    2013-11-15

    Ab initio modelling of fission products (i.e. Nb, Y, Gd, Nd, Zr, Sm, Eu, Ce, Ba, Mo, Sr, Rh, Pd, and Ru) in uranium nitride is carried out by assessing the incorporation, along with their contributions to local swelling of the fuel matrix. Fission products (FP's) in UN have shown to be preferably accommodated at U vacancies in bound [1 0 0]-Schottky defects, nevertheless, similar incorporation energies were found at a single U vacancy. From the investigated incorporation and migration mechanism, we found that FP's in UN predominately migrate along U–U vacancies, since the incorporation energies for all FP are lowest at single U vacancy or at the U vacancy in a Schottky defect. The energy required to induce a migration of a volatile FP from an N vacancy to U vacancy is about 4–5.5 eV. The local volume changes caused by the fission-product substitution have been assessed by means of DFT and combined with the fission-product concentrations obtained by means of neutron calculations (SCALE) to predict fission product swelling in UN. The linear swelling of nitride fuel resulting from these calculations, and the assumption that fission products do not interact and form secondary phases, leads to a reasonable estimation for the swelling rate as a function of burn-up (or time) when compared with empirical correlations in the open literature.

  12. Temperature dependent fission product removal efficiency due to pool scrubbing

    Energy Technology Data Exchange (ETDEWEB)

    Uchida, Shunsuke, E-mail: suchida@iae.or.jp [Institute of Applied Energy, 1-14-2, Nishi-Shimbashi, Minato-ku, Tokyo 105-0003 (Japan); Itoh, Ayumi; Naitoh, Masanori; Okada, Hidetoshi; Suzuki, Hiroyuki [Institute of Applied Energy, 1-14-2, Nishi-Shimbashi, Minato-ku, Tokyo 105-0003 (Japan); Hanamoto, Yukio [KAKEN, Inc., 1044, Hori-machi, Mito 310-0903 (Japan); Osakabe, Masahiro [Tokyo University of Marine Science & Technology, Koutou-ku, Tokyo 135-8533 (Japan); Fujikawa, Masahiro [Japan Broadcasting Corporation, 2-2-1, Jinnan, Shibuya-ku, Tokyo 150-8001 (Japan)

    2016-03-15

    Highlights: • Pool temperature effects on the FP removal were not clearly concluded in the previous publications. • It was confirmed that the removal efficiency decreased with temperature around the boiling point. • A modified empirical formula for FP removal was proposed as a function of sub-cooling temperature. • DF could be predicted with an accuracy within a factor of 2 with the proposed formula. - Abstract: The wet-well of boiling water reactors plays important roles not only to suppress the pressure in the primary containment vessel due to steam scrubbing effects during severe accidents but also to mitigate release of radioactive fission products (FP), aerosols and particulates, into the environment. The effects of steam scrubbing in the wet-well on FP removal have been well studied and reported by changing major parameters determining the removal efficiencies, e.g., aerosol diameters, submergence (depth of scrubbing nozzles) and steam/non-condensable gas volume fraction. Unfortunately, the effects of pool temperature on the FP removal were not clearly concluded in the previous publications, though it would be easily expected that boiling in the pool resulted in reduced aerosol removal efficiency. In order to determine the temperature effects on FP removal efficiency, amounts of cesium in aerosols released from scrubbing pool were measured by changing pool temperature in mini and medium scale scrubbing experiments, and then, it was confirmed that the removal efficiency clearly decreased with temperature around the boiling point. Then, a modified empirical formula to express the FP removal around the boiling point temperature was proposed as a function of sub-cooling temperature by applying the effective steam volume fraction, which was designated as the volume ratio of condensed steam in the pool versus the sum of input steam and non-condensable gas. By comparing the measured removal efficiency with the calculated, it was validated that the

  13. Photo-fission for the production of radioactive beams ALTO project

    CERN Document Server

    Essabaa, S; Ausset, P; Bajeat, O; Baronick, J P; Clapier, F; Coacolo, J L; Donzaud, C; Ducourtieux, M; Galas, S; Gardes, D; Grialou, D; Hosni, F; Guillemaud-Müller, D; Ibrahim, F; Junquera, T; Lau, C; Le Blanc, F; Lefort, H; Le Scornet, J C; Lesrel, J; Müller, A C; Obert, J; Perru, O; Potier, J C; Proust, J; Pougheon, F; Roussière, B; Rouvière, N; Sauvage, J; Sorlin, O; Tkatchenko, A; Verney, D; Waast, B; Rinolfi, Louis; Rossat, G; Forkel-Wirth, Doris; Müller, A; Bienvenu, G; Bourdon, J C; Garvey, Terence; Jacquemard, B; Omeich, M

    2003-01-01

    In order to probe neutron rich radioactive noble gases produced by photo-fission, a PARRNe-1 experiment (Production d'Atomes Radioactifs Riches en Neutrons) has been carried out at CERN. The incident electron beam of 50 MeV was delivered by the LIL machine: LEP Injector Linac. The experiment allowed us to compare under the same conditions two production methods of radioactive noble gases: fission induced by fast neutrons and photo-fission. The obtained results show that the use of the electrons is a promising mode to get intense neutron rich ion beams. After the success of this photo-fission experiment, a conceptual design for the installation at IPN Orsay of a 50 MeV electron accelerator close to the PARRNe-2 device has been worked out: ALTO Project. This work has started within a collaboration between IPNO, LAL (Laboratoire de l'Accelerateur Lineaire) and CERN groups.

  14. Photo-fission for the production of radioactive beams ALTO project

    Energy Technology Data Exchange (ETDEWEB)

    Essabaa, S. E-mail: essabaa@ipno.in2p3.fr; Arianer, J.; Ausset, P.; Bajeat, O.; Baronick, J.P.; Clapier, F.; Coacolo, L.; Donzaud, C.; Ducourtieux, M.; Gales, S.; Gardes, D.; Grialou, D.; Hosni, F.; Guillemaud-Mueller, D.; Ibrahim, F.; Junquera, T.; Lau, C.; Le Blanc, F.; Lefort, H.; Le Scornet, J.C.; Lesrel, J.; Mueller, A.C.; Obert, J.; Perru, O.; Potier, J.C.; Proust, J.; Pougheon, F.; Roussiere, B.; Rouviere, N.; Sauvage, J.; Sorlin, O.; Tkatchenko, A.; Verney, D.; Waast, B.; Rinolfi, L.; Rossat, G.; Forkel-Wirth, D.; Muller, A.; Bienvenu, G.; Bourdon, J.-C.; Garvey, T.; Jacquemard, B.; Omeich, M

    2003-05-01

    In order to probe neutron rich radioactive noble gases produced by photo-fission, a PARRNe-1 experiment (Production d'Atomes Radioactifs Riches en Neutrons) has been carried out at CERN. The incident electron beam of 50 MeV was delivered by the LIL machine: LEP Injector Linac. The experiment allowed us to compare under the same conditions two production methods of radioactive noble gases: fission induced by fast neutrons and photo-fission. The obtained results show that the use of the electrons is a promising mode to get intense neutron rich ion beams. After the success of this photo-fission experiment, a conceptual design for the installation at IPN Orsay of a 50 MeV electron accelerator close to the PARRNe-2 device has been worked out: ALTO Project. This work has started within a collaboration between IPNO, LAL (Laboratoire de l'Accelerateur Lineaire) and CERN groups.

  15. Curves and tables of neutron cross sections of fission product nuclei in JENDL-3

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawa, Tsuneo [ed.

    1992-06-15

    Neutron cross sections of 172 nuclei in the fission product region stored in JENDL-3 are shown in graphs and tables. The evaluation work of these nuclei was made by the Fission Product Nuclear Data Working Group of the Japanese Nuclear Data Committee, in the neutron energy region from 10{sup {minus}5} eV to 20 MeV. Almost of the cross section data reproduced in graphs in this report. The cross section averaged over 38 energy intervals are listed in a table. Shown in order tables are thermal cross sections, resonance integrals, Maxwellian neutron flux average cross sections, fission spectrum average cross sections, 14-MeV cross sections, one group average cross sections in neutron flux of typical types of fission reactors and average cross sections in the 30-keV Maxwellian spectrum.

  16. Experimental determination of the antineutrino spectrum of the fission products of {sup 238}U

    Energy Technology Data Exchange (ETDEWEB)

    Haag, Nils-Holger

    2013-10-09

    Fission of {sup 238}U contributes about 10 % to the antineutrino emission of a pressurized water reactor. In the present thesis, the beta spectrum of the fission products of {sup 238}U was determined in an experiment at the neutron source FRM II. This beta spectrum was subsequently converted into an antineutrino spectrum. This first measurement of the antineutrino spectrum supports all current and future reactor antineutrino experiments.

  17. Nuclear Power from Fission Reactors. An Introduction.

    Science.gov (United States)

    Department of Energy, Washington, DC. Technical Information Center.

    The purpose of this booklet is to provide a basic understanding of nuclear fission energy and different fission reaction concepts. Topics discussed are: energy use and production, current uses of fuels, oil and gas consumption, alternative energy sources, fossil fuel plants, nuclear plants, boiling water and pressurized water reactors, the light…

  18. Evaluation of fission product worth margins in PWR spent nuclear fuel burnup credit calculations.

    Energy Technology Data Exchange (ETDEWEB)

    Blomquist, R.N.; Finck, P.J.; Jammes, C.; Stenberg, C.G.

    1999-02-17

    Current criticality safety calculations for the transportation of irradiated LWR fuel make the very conservative assumption that the fuel is fresh. This results in a very substantial overprediction of the actual k{sub eff} of the transportation casks; in certain cases, this decreases the amount of spent fuel which can be loaded in a cask, and increases the cost of transporting the spent fuel to the repository. Accounting for the change of reactivity due to fuel depletion is usually referred to as ''burnup credit.'' The US DOE is currently funding a program aimed at establishing an actinide only burnup credit methodology (in this case, the calculated reactivity takes into account the buildup or depletion of a limited number of actinides). This work is undergoing NRC review. While this methodology is being validated on a significant experimental basis, it implicitly relies on additional margins: in particular, the absorption of neutrons by certain actinides and by all fission products is not taken into account. This provides an important additional margin and helps guarantee that the methodology is conservative provided these neglected absorption are known with reasonable accuracy. This report establishes the accuracy of fission product absorption rate calculations: (1) the analysis of European fission product worth experiments demonstrates that fission product cross-sections available in the US provide very good predictions of fission product worth; (2) this is confirmed by a direct comparison of European and US cross section evaluations; (3) accuracy of Spent Nuclear Fuel (SNF) fission product content predictions is established in a recent ORNL report where several SNF isotopic assays are analyzed; and (4) these data are then combined to establish in a conservative manner the fraction of the predicted total fission product absorption which can be guaranteed based on available experimental data.

  19. Fusion-Fission Hybrid for Fissile Fuel Production without Processing

    Energy Technology Data Exchange (ETDEWEB)

    Fratoni, M; Moir, R W; Kramer, K J; Latkowski, J F; Meier, W R; Powers, J J

    2012-01-02

    Two scenarios are typically envisioned for thorium fuel cycles: 'open' cycles based on irradiation of {sup 232}Th and fission of {sup 233}U in situ without reprocessing or 'closed' cycles based on irradiation of {sup 232}Th followed by reprocessing, and recycling of {sup 233}U either in situ or in critical fission reactors. This study evaluates a third option based on the possibility of breeding fissile material in a fusion-fission hybrid reactor and burning the same fuel in a critical reactor without any reprocessing or reconditioning. This fuel cycle requires the hybrid and the critical reactor to use the same fuel form. TRISO particles embedded in carbon pebbles were selected as the preferred form of fuel and an inertial laser fusion system featuring a subcritical blanket was combined with critical pebble bed reactors, either gas-cooled or liquid-salt-cooled. The hybrid reactor was modeled based on the earlier, hybrid version of the LLNL Laser Inertial Fusion Energy (LIFE1) system, whereas the critical reactors were modeled according to the Pebble Bed Modular Reactor (PBMR) and the Pebble Bed Advanced High Temperature Reactor (PB-AHTR) design. An extensive neutronic analysis was carried out for both the hybrid and the fission reactors in order to track the fuel composition at each stage of the fuel cycle and ultimately determine the plant support ratio, which has been defined as the ratio between the thermal power generated in fission reactors and the fusion power required to breed the fissile fuel burnt in these fission reactors. It was found that the maximum attainable plant support ratio for a thorium fuel cycle that employs neither enrichment nor reprocessing is about 2. This requires tuning the neutron energy towards high energy for breeding and towards thermal energy for burning. A high fuel loading in the pebbles allows a faster spectrum in the hybrid blanket; mixing dummy carbon pebbles with fuel pebbles enables a softer spectrum in

  20. Fission products, activity calculation of spent-fuel

    Energy Technology Data Exchange (ETDEWEB)

    Souka, N.; El-Hakiem, M.N.

    1981-01-01

    This work is a scrutiny of the activity of burned up fuel elements of the ET-RR-1. A knowledge of this activity as well as its decay with time is quite helpful in shielding calculations related to construction purposes of hot facilities. The present treatment is based on a knowledge of: fuel composition, percentage burnup, and fission yields of produced isotopes. Cooling periods ranging from 1 hr to 10 years were considered.

  1. Uncertainties in fission-product decay-heat calculations

    Energy Technology Data Exchange (ETDEWEB)

    Oyamatsu, K.; Ohta, H.; Miyazono, T.; Tasaka, K. [Nagoya Univ. (Japan)

    1997-03-01

    The present precision of the aggregate decay heat calculations is studied quantitatively for 50 fissioning systems. In this evaluation, nuclear data and their uncertainty data are taken from ENDF/B-VI nuclear data library and those which are not available in this library are supplemented by a theoretical consideration. An approximate method is proposed to simplify the evaluation of the uncertainties in the aggregate decay heat calculations so that we can point out easily nuclei which cause large uncertainties in the calculated decay heat values. In this paper, we attempt to clarify the justification of the approximation which was not very clear at the early stage of the study. We find that the aggregate decay heat uncertainties for minor actinides such as Am and Cm isotopes are 3-5 times as large as those for {sup 235}U and {sup 239}Pu. The recommended values by Atomic Energy Society of Japan (AESJ) were given for 3 major fissioning systems, {sup 235}U(t), {sup 239}Pu(t) and {sup 238}U(f). The present results are consistent with the AESJ values for these systems although the two evaluations used different nuclear data libraries and approximations. Therefore, the present results can also be considered to supplement the uncertainty values for the remaining 17 fissioning systems in JNDC2, which were not treated in the AESJ evaluation. Furthermore, we attempt to list nuclear data which cause large uncertainties in decay heat calculations for the future revision of decay and yield data libraries. (author)

  2. The Effect of Water Injection on the Fission Product Aerosol Behavior in Fukushima Unit 1

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Il; Ha, Kwang Soon; Kim, Dong Ha; Kim, Tae Woon [KAERI, Daejeon (Korea, Republic of)

    2015-05-15

    The most important factor affects human health is fission product that is released from the plant. Fission products usually released with types of aerosol and vapor. The amount of released aerosols out of the plant is crucial, because it can be breathed by people. In this study, the best estimated scenario of Fukushima unit 1 accident was modeled with MELCOR. The amount of released fission product aerosols was estimated according to the amount of added water into reactor pressure vessel (RPV). The analysis of Fukushima unit 1 accident was conducted in view of fission product aerosol release using MELCOR. First of all, thermodynamic results of the plant were compared to the measured data, and then fission product aerosol (CsOH) behavior was calculated with changing the amount of water injection. Water injection affects the amount of aerosol which released into reactor building, because it decreases the temperature of deposition surface. In this study, only aerosol behavior was considered, further study will be conducted including hygroscopic model.

  3. Comparison of actinides and fission products recycling scheme with the normal plutonium recycling scheme in fast reactors

    Directory of Open Access Journals (Sweden)

    Salahuddin Asif

    2013-01-01

    Full Text Available Multiple recycling of actinides and non-volatile fission products in fast reactors through the dry re-fabrication/reprocessing atomics international reduction oxidation process has been studied as a possible way to reduce the long-term potential hazard of nuclear waste compared to that resulting from reprocessing in a wet PUREX process. Calculations have been made to compare the actinides and fission products recycling scheme with the normal plutonium recycling scheme in a fast reactor. For this purpose, the Karlsruhe version of isotope generation and depletion code, KORIGEN, has been modified accordingly. An entirely novel fission product yields library for fast reactors has been created which has replaced the old KORIGEN fission products library. For the purposes of this study, the standard 26 groups data set, KFKINR, developed at Forschungszentrum Karlsruhe, Germany, has been extended by the addition of the cross-sections of 13 important actinides and 68 most important fission products. It has been confirmed that these 68 fission products constitute about 95% of the total fission products yield and about 99.5% of the total absorption due to fission products in fast reactors. The amount of fissile material required to guarantee the criticality of the reactor during recycling schemes has also been investigated. Cumulative high active waste per ton of initial heavy metal is also calculated. Results show that the recycling of actinides and fission products in fast reactors through the atomics international reduction oxidation process results in a reduction of the potential hazard of radioactive waste.

  4. A theoretical study of volatile fission products release from oxide fuels

    Energy Technology Data Exchange (ETDEWEB)

    Paraschiv, M.C.; Paraschiv, A. [Inst. for Nucl. Res., Pitesti (Romania); Grecu, V.V. [University of Bucharest, Faculty of Physics, P.O. Box MG-11, Bucharest (Romania)

    1999-11-01

    Treating the average volume grains as thermodynamically closed subsystems, a method to evaluate the volatile fission products migration at the grain boundary and their release in the void volume of the fuel elements is proposed. The method considers the phenomena of the intergranular bubble growth and interlinkage, grain growth and grain boundary resolution. Analytical solutions of the diffusion problem associated with the volatile fission products behaviour taking into account their direct yield from fission and from precursors simultaneously with the diffusion and decay, irradiation induced resolution and fuel grain growth, during a time-step varying irradiation history have also been derived. The results are very accurate and point out the strong effect of the boundary condition changes on the volatile fission products behaviour when the simultaneous effects of the intergranular bubble coalescence, the precursors, the irradiation induced resolution and grain growth are considered. Comparative analyses versus other similar models of the diffusion of only stable gas species of fission products are also presented. (orig.)

  5. Theoretical and experimental studies of the neutron rich fission product yields at intermediate energies

    Directory of Open Access Journals (Sweden)

    Äystö J.

    2012-02-01

    Full Text Available A new method to measure the fission product independent yields employing the ion guide technique and a Penning trap as a precision mass filter, which allows an unambiguous identification of the nuclides is presented. The method was used to determine the independent yields in the proton-induced fission of 232Th and 238U at 25 MeV. The data were analyzed with the consistent model for description of the fission product formation cross section at the projectile energies up to 100 MeV. Pre-compound nucleon emission is described with the two-component exciton model using Monte Carlo method. Decay of excited compound nuclei is treated within time-dependent statistical model with inclusion of the nuclear friction effect. The charge distribution of the primary fragment isobaric chain was considered as a result of frozen quantal fluctuations of the isovector nuclear density. The theoretical predictions of the independent fission product cross sections are used for normalization of the measured fission product isotopic distributions.

  6. Immobilization of fission products arising from pyrometallurgical reprocessing in chloride media

    Science.gov (United States)

    Leturcq, G.; Grandjean, A.; Rigaud, D.; Perouty, P.; Charlot, M.

    2005-12-01

    Spent nuclear fuel reprocessing to recover energy-producing elements such as uranium or plutonium can be performed by a pyrochemical process. In such method, the actinides and fission products are extracted by electrodeposition in a molten chloride medium. These processes generate chlorinated alkali salt flows contaminated by fission products, mainly Cs, Ba, Sr and rare earth elements constituting high-level waste. Two possible alternatives are investigated for managing this wasteform; a protocol is described for dechlorinating the fission products to allow vitrification, and mineral phases capable of immobilizing chlorides are listed to allow specification of a dedicated ceramic matrix suitable for containment of these chlorinated waste streams. The results of tests to synthesize chlorosilicate phases are also discussed.

  7. Augmentation of ENDF/B fission product gamma-ray spectra by calculated spectra

    Energy Technology Data Exchange (ETDEWEB)

    Katakura, J. (Japan Atomic Energy Research Inst., Tokai-mura, Naka-gun, Ibaraki-ken (Japan)); England, T.R. (Los Alamos National Lab., NM (United States))

    1991-11-01

    Gamma-ray spectral data of the ENDF/B-V fission product decay data file have been augmented by calculated spectra. The calculations were performed with a model using beta strength functions and cascade gamma-ray transitions. The calculated spectra were applied to individual fission product nuclides. Comparisons with several hundred measured aggregate gamma spectra after fission were performed to confirm the applicability of the calculated spectra. The augmentation was extended to a preliminary ENDF/B-VI file, and to beta spectra. Appendix C provides information on the total decay energies for individual products and some comparisons of measured and aggregate values based on the preliminary ENDF/B-VI files. 15 refs., 411 figs.

  8. Investigation of the diffusion of atomic fission products in UC by density functional calculations

    Energy Technology Data Exchange (ETDEWEB)

    Bévillon, Émile, E-mail: emile.bevillon@yahoo.fr [IRSN, SEMIC, DPAM, LETR, Centre de Cadarache, 13115 Saint Paul Lez Durance (France); Ducher, Roland; Barrachin, Marc; Dubourg, Roland [IRSN, SEMIC, DPAM, LETR, Centre de Cadarache, 13115 Saint Paul Lez Durance (France)

    2013-03-15

    Activation energies of U and C atoms self-diffusion in UC, as well as activation energies of hetero-diffusion of fission products (FPs) are investigated by first-principles calculations. According to a previous study which showed a likely U site occupation was favoured for all the FPs, their diffusion is restricted to the uranium sublattice of UC in the present study. In this framework, long-range displacements are only possible through a concerted mechanism with a surrounding uranium vacancy. Using the apparent formation energies of the uranium vacancy defect calculated in our previous study and the classical approach used in UO{sub 2} by Andersson et al., the activation energies of the main fission products in the various stoichiometric domains have been calculated. The results are compared to those obtained with the five frequency model applied to two representative fission products, Xe and Zr. Interestingly, despite strong differences of formalism, both models provided similar activation energies.

  9. Investigation of the diffusion of atomic fission products in UC by density functional calculations

    Science.gov (United States)

    Bévillon, Émile; Ducher, Roland; Barrachin, Marc; Dubourg, Roland

    2013-03-01

    Activation energies of U and C atoms self-diffusion in UC, as well as activation energies of hetero-diffusion of fission products (FPs) are investigated by first-principles calculations. According to a previous study which showed a likely U site occupation was favoured for all the FPs, their diffusion is restricted to the uranium sublattice of UC in the present study. In this framework, long-range displacements are only possible through a concerted mechanism with a surrounding uranium vacancy. Using the apparent formation energies of the uranium vacancy defect calculated in our previous study and the classical approach used in UO2 by Andersson et al., the activation energies of the main fission products in the various stoichiometric domains have been calculated. The results are compared to those obtained with the five frequency model applied to two representative fission products, Xe and Zr. Interestingly, despite strong differences of formalism, both models provided similar activation energies.

  10. Most probable charge of fission products in proton-induced fission of sup 2 sup 3 sup 8 U and sup 2 sup 3 sup 2 Th

    CERN Document Server

    Kaji, D; Kudo, H; Fujita, M; Shinozuka, T; Fujioka, M

    2002-01-01

    The charge distributions of fission products in proton-induced fission of sup 2 sup 3 sup 8 U and sup 2 sup 3 sup 2 Th were measured in a wide mass range. The most probable charges lay on the proton-rich side in the light fragment region and on the proton-deficient side in the heavy one compared with the unchanged charge distribution hypothesis. This result implies that the charge polarization occurs in the fission process. The charge polarization was examined with respect to the ground-state Q values. The estimations by the Q values fairly well reproduced the experimental most probable charges. These results suggest that the fission path to the most favorable charge division may go through the most energetically favorable path at scission point. (author)

  11. Diffusion of fission products and radiation damage in SiC

    Science.gov (United States)

    Malherbe, Johan B.

    2013-11-01

    A major problem with most of the present nuclear reactors is their safety in terms of the release of radioactivity into the environment during accidents. In some of the future nuclear reactor designs, i.e. Generation IV reactors, the fuel is in the form of coated spherical particles, i.e. TRISO (acronym for triple coated isotropic) particles. The main function of these coating layers is to act as diffusion barriers for radioactive fission products, thereby keeping these fission products within the fuel particles, even under accident conditions. The most important coating layer is composed of polycrystalline 3C-SiC. This paper reviews the diffusion of the important fission products (silver, caesium, iodine and strontium) in SiC. Because radiation damage can induce and enhance diffusion, the paper also briefly reviews damage created by energetic neutrons and ions at elevated temperatures, i.e. the temperatures at which the modern reactors will operate, and the annealing of the damage. The interaction between SiC and some fission products (such as Pd and I) is also briefly discussed. As shown, one of the key advantages of SiC is its radiation hardness at elevated temperatures, i.e. SiC is not amorphized by neutrons or bombardment at substrate temperatures above 350 °C. Based on the diffusion coefficients of the fission products considered, the review shows that at the normal operating temperatures of these new reactors (i.e. less than 950 °C) the SiC coating layer is a good diffusion barrier for these fission products. However, at higher temperatures the design of the coated particles needs to be adapted, possibly by adding a thin layer of ZrC.

  12. HTGR accident initiation and progression analysis status report. Volume V. AIPA fission product source terms

    Energy Technology Data Exchange (ETDEWEB)

    Alberstein, D.; Apperson, C.E. Jr.; Hanson, D.L.; Myers, B.F.; Pfeiffer, W.W.

    1976-02-01

    The primary objective of the Accident Initiation and Progression Analysis (AIPA) Program is to provide guidance for high-temperature gas-cooled reactor (HTGR) safety research and development. Among the parameters considered in estimating the uncertainties in site boundary doses are uncertainties in fission product source terms generated under normal operating conditions, i.e., fuel body inventories, circulating coolant activity, total plateout activity in the primary circuit, and plateout distributions. The volume presented documents the analyses of these source term uncertainties. The results are used for the detailed consequence evaluations, and they provide the basis for evaluation of fission products important for HTGR maintenance and shielding.

  13. Experimental Determination of the Antineutrino Spectrum of the Fission Products of $^{238}$U

    CERN Document Server

    Haag, N; Hofmann, M; Oberauer, L; Potzel, W; Schreckenbach, K; Wagner, F M

    2013-01-01

    An experiment was performed at the scientific neutron source FRM II in Garching to determine the cumulative antineutrino spectrum of the fission products of $^{238}$U. This was achieved by irradiating target foils of natural uranium with a thermal and a fast neutron beam and recording the emitted $\\beta$-spectra with a gamma-suppressing electron-telescope. The obtained $\\beta$-spectrum of the fission products of $^{235}$U was normalized to the data of the magnetic spectrometer BILL of $^{235}$U. This method strongly reduces systematic errors in the $^{238}$U measurement. The $\\beta$-spectrum of $^{238}$U was converted into the corresponding antineutrino spectrum. The final $\\bar\

  14. Study on the Separation of 132Te From Fission Products by Precipitation

    Institute of Scientific and Technical Information of China (English)

    MAOGuo-shu; ZHANGSheng-dong; CUIAn-zhi; GUOJing-ru; YANGLei; DINGYou-qian

    2003-01-01

    In order to measure precisely the decay data of 132I, radiochemical purity 132I is directly or indirectly separated and prepared from fission products of 235U. The source of 132I which is separated directly has some isotope nuclides such as 131I, 133I, 135I etc. that interfere measurement of 132I by HPGe γ detector. The method of 132I separated indirectly has two steps: 1) Its mother nuclide 132Te is separated from fission products; 2) 132I is separated from 132Te. By this method, the interference of other isotope nuclides of 132I is greatly decreased and even eliminated.

  15. Basic analysis of regularized series and products

    CERN Document Server

    Jorgenson, Jay A

    1993-01-01

    Analytic number theory and part of the spectral theory of operators (differential, pseudo-differential, elliptic, etc.) are being merged under amore general analytic theory of regularized products of certain sequences satisfying a few basic axioms. The most basic examples consist of the sequence of natural numbers, the sequence of zeros with positive imaginary part of the Riemann zeta function, and the sequence of eigenvalues, say of a positive Laplacian on a compact or certain cases of non-compact manifolds. The resulting theory is applicable to ergodic theory and dynamical systems; to the zeta and L-functions of number theory or representation theory and modular forms; to Selberg-like zeta functions; andto the theory of regularized determinants familiar in physics and other parts of mathematics. Aside from presenting a systematic account of widely scattered results, the theory also provides new results. One part of the theory deals with complex analytic properties, and another part deals with Fourier analys...

  16. Method of fission product beta spectra measurements for predicting reactor anti-neutrino emission

    Energy Technology Data Exchange (ETDEWEB)

    Asner, D.M.; Burns, K.; Campbell, L.W.; Greenfield, B.; Kos, M.S., E-mail: markskos@gmail.com; Orrell, J.L.; Schram, M.; VanDevender, B.; Wood, L.S.; Wootan, D.W.

    2015-03-11

    The nuclear fission process that occurs in the core of nuclear reactors results in unstable, neutron-rich fission products that subsequently beta decay and emit electron antineutrinos. These reactor neutrinos have served neutrino physics research from the initial discovery of the neutrino to today's precision measurements of neutrino mixing angles. The prediction of the absolute flux and energy spectrum of the emitted reactor neutrinos hinges upon a series of seminal papers based on measurements performed in the 1970s and 1980s. The steadily improving reactor neutrino measurement techniques and recent reconsiderations of the agreement between the predicted and observed reactor neutrino flux motivates revisiting the underlying beta spectra measurements. A method is proposed to use an accelerator proton beam delivered to an engineered target to yield a neutron field tailored to reproduce the neutron energy spectrum present in the core of an operating nuclear reactor. Foils of the primary reactor fissionable isotopes placed in this tailored neutron flux will ultimately emit beta particles from the resultant fission products. Measurement of these beta particles in a time projection chamber with a perpendicular magnetic field provides a distinctive set of systematic considerations for comparison to the original seminal beta spectra measurements. Ancillary measurements such as gamma-ray emission and post-irradiation radiochemical analysis will further constrain the absolute normalization of beta emissions per fission. The requirements for unfolding the beta spectra measured with this method into a predicted reactor neutrino spectrum are explored.

  17. Method of fission product beta spectra measurements for predicting reactor anti-neutrino emission

    Energy Technology Data Exchange (ETDEWEB)

    Asner, David M.; Burns, Kimberly A.; Campbell, Luke W.; Greenfield, Bryce A.; Kos, Marek S.; Orrell, John L.; Schram, Malachi; VanDevender, Brent A.; Wood, Lynn S.; Wootan, David W.

    2015-03-01

    The nuclear fission process that occurs in the core of nuclear reactors results in unstable, neutron-rich fission products that subsequently beta decay and emit electron antineutrinos. These reactor neutrinos have served neutrino physics research from the initial discovery of the neutrino to today's precision measurements of neutrino mixing angles. The prediction of the absolute flux and energy spectrum of the emitted reactor neutrinos hinges upon a series of seminal papers based on measurements performed in the 1970s and 1980s. The steadily improving reactor neutrino measurement techniques and recent reconsiderations of the agreement between the predicted and observed reactor neutrino flux motivates revisiting the underlying beta spectra measurements. A method is proposed to use an accelerator proton beam delivered to an engineered target to yield a neutron field tailored to reproduce the neutron energy spectrum present in the core of an operating nuclear reactor. Foils of the primary reactor fissionable isotopes placed in this tailored neutron flux will ultimately emit beta particles from the resultant fission products. Measurement of these beta particles in a time projection chamber with a perpendicular magnetic field provides a distinctive set of systematic considerations for comparison to the original seminal beta spectra measurements. Ancillary measurements such as gamma-ray emission and post-irradiation radiochemical analysis will further constrain the absolute normalization of beta emissions per fission. The requirements for unfolding the beta spectra measured with this method into a predicted reactor neutrino spectrum are explored.

  18. Fission Product Yields from 232Th, 238U, and 235U Using 14 MeV Neutrons

    Science.gov (United States)

    Pierson, B. D.; Greenwood, L. R.; Flaska, M.; Pozzi, S. A.

    2017-01-01

    Neutron-induced fission yield studies using deuterium-tritium fusion-produced 14 MeV neutrons have not yet directly measured fission yields from fission products with half-lives on the order of seconds (far from the line of nuclear stability). Fundamental data of this nature are important for improving and validating the current models of the nuclear fission process. Cyclic neutron activation analysis (CNAA) was performed on three actinide targets-thorium-oxide, depleted uranium metal, and highly enriched uranium metal-at the University of Michigan's Neutron Science Laboratory (UM-NSL) using a pneumatic system and Thermo-Scientific D711 accelerator-based fusion neutron generator. This was done to measure the fission yields of short-lived fission products and to examine the differences between the delayed fission product signatures of the three actinides. The measured data were compared against previously published results for 89Kr, -90, and -92 and 138Xe, -139, and -140. The average percent deviation of the measured values from the Evaluated Nuclear Data Files VII.1 (ENDF/B-VII.1) for thorium, depleted-uranium, and highly-enriched uranium were -10.2%, 4.5%, and -12.9%, respectively. In addition to the measurements of the six known fission products, 23 new fission yield measurements from 84As to 146La are presented.

  19. Nuclear transmutation strategies for management of long-lived fission products

    Indian Academy of Sciences (India)

    S Kailas; M Hemalatha; A Saxena

    2015-09-01

    Management of long-lived nuclear waste produced in a reactor is essential for long-term sustenance of nuclear energy programme. A number of strategies are being explored for the effective transmutation of long-lived nuclear waste in general, and long-lived fission products (LLFP), in particular. Some of the options available for the transmutation of LLFP are discussed.

  20. Nuclear data project in Korea and resonance parameter evaluation of fission products

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Jonghwa; Oh, Soo-Youl [Korea Atomic Energy Research Institute, Yusong, Taejon (Korea)

    2000-03-01

    Nuclear data activities in the fields of evaluation, processing, measurement, and service in Korea are presented in this paper. As one of the current activities, the neutron resonance parameters for stable or long-lived nineteen fission products have been evaluated and the results are presented here. (author)

  1. Report on the Behavior of Fission Products in the Co-decontamination Process

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Leigh Robert [Idaho National Lab. (INL), Idaho Falls, ID (United States); Riddle, Catherine Lynn [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-30

    This document was prepared to meet FCT level 3 milestone M3FT-15IN0302042, “Generate Zr, Ru, Mo and Tc data for the Co-decontamination Process.” This work was carried out under the auspices of the Lab-Scale Testing of Reference Processes FCT work package. This document reports preliminary work in identifying the behavior of important fission products in a Co-decontamination flowsheet. Current results show that Tc, in the presence of Zr alone, does not behave as the Argonne Model for Universal Solvent Extraction (AMUSE) code would predict. The Tc distribution is reproducibly lower than predicted, with Zr distributions remaining close to the AMUSE code prediction. In addition, it appears there may be an intricate relationship between multiple fission product metals, in different combinations, that will have a direct impact on U, Tc and other important fission products such as Zr, Mo, and Rh. More extensive testing is required to adequately predict flowsheet behavior for these variances within the fission products.

  2. Method of Fission Product Beta Spectra Measurements for Predicting Reactor Anti-neutrino Emission

    CERN Document Server

    Asner, D M; Campbell, L W; Greenfield, B; Kos, M S; Orrell, J L; Schram, M; VanDevender, B; Wood, 1 L S; Wootan, D W

    2014-01-01

    The nuclear fission process that occurs in the core of nuclear reactors results in unstable, neutron rich fission products that subsequently beta decay and emit electron anti-neutrinos. These reactor neutrinos have served neutrino physics research from the initial discovery of the neutrino to current precision measurements of neutrino mixing angles. The prediction of the absolute flux and energy spectrum of the emitted reactor neutrinos hinges upon a series of seminal papers based on measurements performed in the 1970s and 1980s. The steadily improving reactor neutrino measurement techniques and recent re-considerations of the agreement between the predicted and observed reactor neutrino flux motivates revisiting the underlying beta spectra measurements. A method is proposed to use an accelerator proton beam delivered to an engineered target to yield a neutron field tailored to reproduce the neutron energy spectrum present in the core of an operating nuclear reactor. Foils of the primary reactor fissionable i...

  3. Comparison of fission product release predictions using PARFUME with results from the AGR-1 irradiation experiment

    Energy Technology Data Exchange (ETDEWEB)

    Blaise Collin

    2014-09-01

    This report documents comparisons between post-irradiation examination measurements and model predictions of silver (Ag), cesium (Cs), and strontium (Sr) release from selected tristructural isotropic (TRISO) fuel particles and compacts during the first irradiation test of the Advanced Gas Reactor program that occurred from December 2006 to November 2009 in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL). The modeling was performed using the particle fuel model computer code PARFUME (PARticle FUel ModEl) developed at INL. PARFUME is an advanced gas-cooled reactor fuel performance modeling and analysis code (Miller 2009). It has been developed as an integrated mechanistic code that evaluates the thermal, mechanical, and physico-chemical behavior of fuel particles during irradiation to determine the failure probability of a population of fuel particles given the particle-to-particle statistical variations in physical dimensions and material properties that arise from the fuel fabrication process, accounting for all viable mechanisms that can lead to particle failure. The code also determines the diffusion of fission products from the fuel through the particle coating layers, and through the fuel matrix to the coolant boundary. The subsequent release of fission products is calculated at the compact level (release of fission products from the compact) but it can be assessed at the particle level by adjusting the diffusivity in the fuel matrix to very high values. Furthermore, the diffusivity of each layer can be individually set to a high value (typically 10-6 m2/s) to simulate a failed layer with no capability of fission product retention. In this study, the comparison to PIE focused on fission product release and because of the lack of failure in the irradiation, the probability of particle failure was not calculated. During the AGR-1 irradiation campaign, the fuel kernel produced and released fission products, which migrated through the successive

  4. Fission Product Transport and Source Terms in HTRs: Experience from AVR Pebble Bed Reactor

    Directory of Open Access Journals (Sweden)

    Rainer Moormann

    2008-01-01

    Full Text Available Fission products deposited in the coolant circuit outside of the active core play a dominant role in source term estimations for advanced small pebble bed HTRs, particularly in design basis accidents (DBA. The deposited fission products may be released in depressurization accidents because present pebble bed HTR concepts abstain from a gas tight containment. Contamination of the circuit also hinders maintenance work. Experiments, performed from 1972 to 88 on the AVR, an experimental pebble bed HTR, allow for a deeper insight into fission product transport behavior. The activity deposition per coolant pass was lower than expected and was influenced by fission product chemistry and by presence of carbonaceous dust. The latter lead also to inconsistencies between Cs plate out experiments in laboratory and in AVR. The deposition behavior of Ag was in line with present models. Dust as activity carrier is of safety relevance because of its mobility and of its sorption capability for fission products. All metal surfaces in pebble bed reactors were covered by a carbonaceous dust layer. Dust in AVR was produced by abrasion in amounts of about 5 kg/y. Additional dust sources in AVR were ours oil ingress and peeling of fuel element surfaces due to an air ingress. Dust has a size of about 1  m, consists mainly of graphite, is partly remobilized by flow perturbations, and deposits with time constants of 1 to 2 hours. In future reactors, an efficient filtering via a gas tight containment is required because accidents with fast depressurizations induce dust mobilization. Enhanced core temperatures in normal operation as in AVR and broken fuel pebbles have to be considered, as inflammable dust concentrations in the gas phase.

  5. Mechanistic approach for nitride fuel evolution and fission product release under irradiation

    Science.gov (United States)

    Dolgodvorov, A. P.; Ozrin, V. D.

    2017-01-01

    A model for describing uranium-plutonium mixed nitride fuel pellet burning was developed. Except fission products generating, the model includes impurities of oxygen and carbon. Nitrogen behaviour in nitride fuel was analysed and the nitrogen chemical potential in solid solution with uranium-plutonium nitride was constructed. The chemical program module was tested with the help of thermodynamic equilibrium phase distribution calculation. Results were compared with analogous data in literature, quite good agreement was achieved, especially for uranium sesquinitride, metallic species and some oxides. Calculation of a process of nitride fuel burning was also conducted. Used mechanistic approaches for fission product evolution give the opportunity to find fission gas release fractions and also volumes of intergranular secondary phases. Calculations present that the most massive secondary phases are the oxide and metallic phases. Oxide phase contain approximately 1 % wt of substance over all time of burning with slightly increasing of content. Metallic phase has considerable rising of mass and by the last stage of burning it contains about 0.6 % wt of substance. Intermetallic phase has less increasing rate than metallic phase and include from 0.1 to 0.2 % wt over all time of burning. The highest element fractions of released gaseous fission products correspond to caesium and iodide.

  6. Determination of uranium fission product interference factor for molybdenum quantification by instrumental neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro Junior, Ibere S.; Saiki, Mitiko; Genezini, Frederico A.; Zahn, Guilherme S., E-mail: ibere@usp.br, E-mail: mitiko@ipen.br, E-mail: fredzini@ipen.br, E-mail: gzahn@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    Instrumental Neutron Activation Analysis (INAA) is a technique that provides high precision and accuracy results for the concentration determinations of several elements in different kinds of matrices. However, if the sample contains high uranium concentration in their composition, INAA can provide inaccurate results due to uranium fission product interferences. The molybdenum is one of these elements that suffers interference by uranium fission product, because the {sup 99}Mo radioisotope formed by {sup 98}Mo neutron capture, used in INAA, is the same that formed in the uranium fission. This kind of interference can be solved by separation of uranium before irradiation or by determining the uranium interference factor to the radioisotope of interest and applying the correction. The present study aims at the following: (1) determination of the Mo interference factor (F{sub Exp}{sup Mo}) due to the uranium fission product {sup 99}Mo by irradiating standards of Mo and U with known masses of these elements (experimental interference factor); (2) determination of the theoretical F{sub Th}{sup Mo}, in this case it was necessary to determine the epithermal to thermal neutron flux ratio and use the reported nuclear parameters; (3) comparison of the results of the interference factor obtained with values reported in the literature. The interference factor for Mo analysis was obtained in a position 14b shelf 3 of the IEA-R1 nuclear research reactor. (author)

  7. Basic contradiction of the international production cooperation

    Directory of Open Access Journals (Sweden)

    Rinas V. Kashbraziyev

    2015-12-01

    Full Text Available Objective to analyze the contradictions of international industrial cooperation as a driving force for its development. Methods identification and analysis of contradictions in international cooperation were carried out using systematic approach based on general scientific methods of theoretical and empirical research analysis synthesis scientific observation measurement and comparison. On the basis of generalization and analysis of the information contained in the statistical system of the Organization for economic cooperation and development and the global competitiveness reports of the world economic forum the author presents assessment of the level of technological and knowledgeintensity of the economies of certain developed and developing transition countries investment efficiency in science and research their influence on the technological level of production and the degree of technological sovereignty of the mentioned countries. Results the study of the industrialized countriesrsquo experience has shown that the production of hightech products is impossible without integration into a global cooperative network of industrial companies and research institutes. However being included into the global production chains and attracting advanced technologies of production marketing and management the national companies inevitably fall into dependence on foreign import supply. An economic axiom is formulated modern hightech production requires a dramatic expansion of international production cooperation. The main ontological contradiction of international industrial cooperation is revealed characterized by the impact on the improvement of the technological level of production and innovativeness of the national economy on the one hand and simultaneous strengthening of its dependence on foreign partners on the other hand. Scientific novelty on the basis of systematic approach the article reveals contradictions in international cooperation in the

  8. Mass yield distributions of fission products from photo-fission of {sup 238}U induced by 11.5-17.3 MeV bremsstrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Naik, H.; Goswami, A. [Bhabha Atomic Research Centre, Radiochemistry Division, Mumbai (India); Carrel, Frederick; Laine, Frederic; Sari, Adrien [SAPHIR Facility, Gif-sur-Yvette (France); Kim, G.N. [Kyungpook National University, Department of Physics, Daegu (Korea, Republic of); Normand, S. [Laboratory of Sensors and Elctronics Architectures CEA, Gif-sur-Yvette (France)

    2013-07-15

    The yields of various fission products in the 11.5, 13.4, 15.0 and 17.3 MeV bremsstrahlung-induced fission of {sup 238}U have been determined by recoil catcher and an off-line {gamma}-ray spectrometric technique using the electron linac, SAPHIR at CEA, Saclay, France. The mass yield distributions were obtained from the fission product yields using charge-distribution corrections. The peak-to-valley (P/V) ratio, average light mass (left angle A{sub L} right angle) and heavy mass (left angle A{sub H} right angle) and average number of neutrons (left angle v right angle) in the bremsstrahlung-induced fission of {sup 238}U at different excitation energies were obtained from the mass yield data. From the present and literature data in the {sup 238}U ({gamma}, f) and {sup 238}U (n, f) reactions at various energies, the following observations were obtained: i) The mass yield distributions in the {sup 238}U ({gamma}, f) reaction at various energies of the present work are double-humped, similar to those of the {sup 238}U (n, f) reaction of comparable excitation energy. ii) The yields of fission products for A = 133-134, A = 138-140, and A = 143-144 and their complementary products in the {sup 238}U ({gamma}, f) reaction are higher than other fission products due to the nuclear structure effect. iii) The yields of fission products for A = 133-134 and their complementary products are slightly higher in the {sup 238}U ({gamma}, f) than in the {sup 238}U (n, f), whereas for A = 138-140 and 143-144 and their complementary products are comparable. iv) With excitation energy, the increase of yields of symmetric products and the decrease of the peak-to-valley (P/V ratio in the {sup 238}U ({gamma}, f) reaction is similar to the {sup 238}U (n, f) reaction. v) The increase of left angle v right angle with excitation energy is also similar between the {sup 238}U ({gamma}, f) and {sup 238}U (n, f) reactions. However, it is surprising to see that the left angle A{sub L} right angle and

  9. Mass yield distributions of fission products from photo-fission of 238U induced by 11.5-17.3 MeV bremsstrahlung

    Science.gov (United States)

    Naik, H.; Carrel, Frédérick; Kim, G. N.; Laine, Frédéric; Sari, Adrien; Normand, S.; Goswami, A.

    2013-07-01

    The yields of various fission products in the 11.5, 13.4, 15.0 and 17.3 MeV bremsstrahlung-induced fission of 238U have been determined by recoil catcher and an off-line γ-ray spectrometric technique using the electron linac, SAPHIR at CEA, Saclay, France. The mass yield distributions were obtained from the fission product yields using charge-distribution corrections. The peak-to-valley ( P/ V ratio, average light mass () and heavy mass () and average number of neutrons () in the bremsstrahlung-induced fission of 238U at different excitation energies were obtained from the mass yield data. From the present and literature data in the 238U ( γ, f ) and 238U ( n, f ) reactions at various energies, the following observations were obtained: i) The mass yield distributions in the 238U ( γ, f ) reaction at various energies of the present work are double-humped, similar to those of the 238U ( n, f ) reaction of comparable excitation energy. ii) The yields of fission products for A = 133-134, A = 138-140, and A = 143-144 and their complementary products in the 238U ( γ, f) reaction are higher than other fission products due to the nuclear structure effect. iii) The yields of fission products for A = 133-134 and their complementary products are slightly higher in the 238U ( γ, f ) than in the 238U ( n, f ) , whereas for A = 138-140 and 143-144 and their complementary products are comparable. iv) With excitation energy, the increase of yields of symmetric products and the decrease of the peak-to-valley ( P/ V ratio in the 238U ( γ, f) reaction is similar to the 238U ( n, f) reaction. v) The increase of with excitation energy is also similar between the 238U ( γ, f ) and 238U ( n, f) reactions. However, it is surprising to see that the and values with excitation energy behave entirely differently from the 238U ( γ, f ) and 238U ( n, f ) reactions.

  10. Irradiation effects and behaviour of fission products in zirconia and spinel; Effets d'irradiation et comportement des produits de fission dans la zircone et le spinelle

    Energy Technology Data Exchange (ETDEWEB)

    Gentils, A

    2003-10-01

    Crystalline oxides, such as zirconia (ZrO{sub 2}) and spinel (MgAl{sub 2}O{sub 4}), are promising inert matrices for the transmutation of plutonium and minor actinides. This work deals with the study of the physico-chemical properties of these matrices, more specifically their behaviour under irradiation and their capacity to retain fission products. Irradiations at low energy and incorporation of stable analogs of fission products (Cs, I, Xe) into yttria-stabilized zirconia and magnesium-aluminate spinel single crystals were performed by using the ion implanter IRMA (CSNSM-Orsay). Irradiations at high energy were made on several heavy ion accelerators (GANIL-Caen, ISL-Berlin, HIL-Warsaw). The damage induced by irradiation and the release of fission products were monitored by in situ Rutherford Backscattering Spectrometry experiments. Transmission electron microscopy was also used in order to determine the nature of the damage induced by irradiation. The results show that irradiation of ZrO{sub 2} and MgAl{sub 2}O{sub 4} with heavy ions (about hundred keV and about hundred MeV) induces a huge structural damage in crystalline matrices. Total disorder (amorphization) is however never reached in zirconia, contrary to what is observed in the case of spinel. The results also emphasize the essential role played by the concentration of implanted species on their retention capacity. A dramatic release of fission products was observed when the concentration exceeds a threshold of a few atomic percent. Irradiation of implanted samples with medium-energy noble-gas ions leads to an enhancement of the fission product release. The exfoliation of spinel crystals implanted at high concentration of Cs ions is observed after a thermal treatment at high temperature. (author)

  11. Exploratory study of fission product yields of neutron-induced fission of 235U , 238U , and 239Pu at 8.9 MeV

    Science.gov (United States)

    Bhatia, C.; Fallin, B. F.; Gooden, M. E.; Howell, C. R.; Kelley, J. H.; Tornow, W.; Arnold, C. W.; Bond, E.; Bredeweg, T. A.; Fowler, M. M.; Moody, W.; Rundberg, R. S.; Rusev, G. Y.; Vieira, D. J.; Wilhelmy, J. B.; Becker, J. A.; Macri, R.; Ryan, C.; Sheets, S. A.; Stoyer, M. A.; Tonchev, A. P.

    2015-06-01

    Using dual-fission chambers each loaded with a thick (200 -400 -mg /c m2) actinide target of 235 ,238U or 239Pu and two thin (˜10 -100 -μ g /c m2) reference foils of the same actinide, the cumulative yields of fission products ranging from 92Sr to 147Nd have been measured at En= 8.9 MeV . The 2H(d ,n ) 3He reaction provided the quasimonoenergetic neutron beam. The experimental setup and methods used to determine the fission product yield (FPY) are described, and results for typically eight high-yield fission products are presented. Our FPYs for 235U(n ,f ) , 238U(n ,f ) , and 239Pu(n ,f ) at 8.9 MeV are compared with the existing data below 8 MeV from Glendenin et al. [Phys. Rev. C 24, 2600 (1981), 10.1103/PhysRevC.24.2600], Nagy et al. [Phys. Rev. C 17, 163 (1978), 10.1103/PhysRevC.17.163], Gindler et al. [Phys. Rev. C 27, 2058 (1983), 10.1103/PhysRevC.27.2058], and those of Mac Innes et al. [Nucl. Data Sheets 112, 3135 (2011), 10.1016/j.nds.2011.11.009] and Laurec et al. [Nucl. Data Sheets 111, 2965 (2010), 10.1016/j.nds.2010.11.004] at 14.5 and 14.7 MeV, respectively. This comparison indicates a negative slope for the energy dependence of most fission product yields obtained from 235U and 239Pu , whereas for 238U the slope issue remains unsettled.

  12. Development of industrial-scale fission {sup 99}Mo production process using low enriched uranium target

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung Kon; Lee, Jun Sig [Radioisotope Research Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Beyer, Gerd J. [Grunicke Strasse 15, Leipzig (Germany)

    2016-06-15

    Molybdenum-99 ({sup 99}Mo) is the most important isotope because its daughter isotope, technetium-99m ({sup 99}mTc), has been the most widely used medical radioisotope for more than 50 years, accounting for > 80% of total nuclear diagnostics worldwide. In this review, radiochemical routes for the production of {sup 99}Mo, and the aspects for selecting a suitable process strategy are discussed from the historical viewpoint of {sup 99}Mo technology developments. Most of the industrial-scale {sup 99}Mo processes have been based on the fission of {sup 235}U. Recently, important issues have been raised for the conversion of fission {sup 99}Mo targets from highly enriched uranium to low enriched uranium (LEU). The development of new LEU targets with higher density was requested to compensate for the loss of {sup 99}Mo yield, caused by a significant reduction of {sup 235}U enrichment, from the conversion. As the dramatic increment of intermediate level liquid waste is also expected from the conversion, an effective strategy to reduce the waste generation from the fission {sup 99}Mo production is required. The mitigation of radioxenon emission from medical radioisotope production facilities is discussed in relation with the monitoring of nuclear explosions and comprehensive nuclear test ban. Lastly, the {sup 99}Mo production process paired with the Korea Atomic Energy Research Institute's own LEU target is proposed as one of the most suitable processes for the LEU target.

  13. Thermochemical prediction of chemical form distributions of fission products in LWR mixed oxide fuels

    Energy Technology Data Exchange (ETDEWEB)

    Moriyama, Kouki; Furuya, Hirotaka [Kyushu Univ., Fukuoka (Japan). Faculty of Engineering

    1998-06-01

    Radial distribution of chemical forms of fission products (FPs) in LWR mixed oxide (MOX) fuel pins was theoretically predicted by a thermochemical computer code SOLGASMIX-PV. The amounts of fission products generated in the fuel were calculated by ORIGEN-2 code, and the radial distributions of temperature and oxygen potential were calculated by taking the neutron depression and oxygen redistribution in the fuel into account. A fuel pellet was radially divided into 51 sections and chemical forms of FPs were calculated in each section. The effects of linear heat rating (LHR) and average O/U ratio on radial distribution of chemical form were evaluated. It was found that the radial distribution of chemical forms depends strongly on the LHR and the O/M ratio, and is not proportional to that of burnup. (author)

  14. Fission product transport and behavior during two postulated loss of flow transients in the air

    Energy Technology Data Exchange (ETDEWEB)

    Adams, J.P.; Carboneau, M.L.

    1991-01-01

    This document discusses fission product behavior during two postulated loss-of-flow accidents (leading to high- and low-pressure core degradation, respectively) in the Advanced Test Reactor (ATR). These transients are designated ATR Transient LCPI5 (high-pressure) and LPP9 (low-pressure). Normally, transients of this nature would be easily mitigated using existing safety systems and procedures. In these analyses, failure of these safety systems was assumed so that core degradation and fission product release could be analyzed. A probabilistic risk assessment indicated that the probability of occurrence for these two transients is of the order of 10{sup {minus}5 }and 10{sup {minus}7} per reactor year for LCP15 and LPP9, respectively.

  15. Fission product transport and behavior during two postulated loss of flow transients in the air

    Energy Technology Data Exchange (ETDEWEB)

    Adams, J.P.; Carboneau, M.L.

    1991-12-31

    This document discusses fission product behavior during two postulated loss-of-flow accidents (leading to high- and low-pressure core degradation, respectively) in the Advanced Test Reactor (ATR). These transients are designated ATR Transient LCPI5 (high-pressure) and LPP9 (low-pressure). Normally, transients of this nature would be easily mitigated using existing safety systems and procedures. In these analyses, failure of these safety systems was assumed so that core degradation and fission product release could be analyzed. A probabilistic risk assessment indicated that the probability of occurrence for these two transients is of the order of 10{sup {minus}5 }and 10{sup {minus}7} per reactor year for LCP15 and LPP9, respectively.

  16. A model for release of fission products from a breached fuel plate under wet storage

    Energy Technology Data Exchange (ETDEWEB)

    Terremoto, L.A.A.; Seerban, R.S.; Zeituni, C.A.; Silva, J.E.R. da; Silva, A.T. e; Castanheira, M.; Lucki, G.; Damy, M. de A.; Teodoro, C.A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mail: laaterre@ipen.br

    2007-07-01

    MTR fuel elements burned-up inside the core of nuclear research reactors are stored worldwide mainly under the water of storage pools. When cladding breach is present in one or more fuel plates of such elements, radioactive fission products are released into the storage pool water. This work proposes a model to describe the release mechanism considering the diffusion of nuclides of a radioactive fission product either through a postulated small cylindrical breach or directly from a large circular hole in the cladding. In each case, an analytical expression is obtained for the activity released into the water as a function of the total storage time of a breached fuel plate. Regarding sipping tests already performed at the IEA-R1 research reactor on breached MTR fuel elements, the proposed model correlates successfully the specific activity of {sup 137}Cs, measured as a function of time, with the evaluated size of the cladding breach. (author)

  17. Measurement of airborne fission products in Chapel Hill, NC, USA from the Fukushima I reactor accident

    CERN Document Server

    MacMullin, S; Green, M P; Henning, R; Holmes, R; Vorren, K; Wilkerson, J F

    2011-01-01

    We present measurements of airborne fission products in Chapel Hill, NC, USA, from 62 days following the March 11, 2011, accident at the Fukushima I Nuclear Power Plant. Airborne particle samples were collected daily in air filters and radio-assayed with two high-purity germanium (HPGe) detectors. The fission products I-131 and Cs-137 were measured with maximum activities of 4.2 +/- 0.6 mBq/m^2 and 0.42 +/- 0.07 mBq/m^2 respectively. Additional activity from I-131, I-132, Cs-134, Cs-136, Cs-137 and Te-132 were measured in the same air filters using a low-background HPGe detector at the Kimballton Underground Research Facility (KURF).

  18. Enhancement of ASTEC and COCOSYS regarding fission product release during MCCI

    Energy Technology Data Exchange (ETDEWEB)

    Agethen, Kathrin [Bochum Univ. (Germany). Reactor Simulation and Safety Group

    2016-10-15

    The focus in this paper is on the enhancement of the fission product release model during molten core concrete interaction in the severe accident analysis codes ASTEC and COCOSYS. After both codes are harmonised and the model interaction as well as the input parameters are adapted, extended model approaches are implemented. These lead to an improvement of the release rates for selected semi-volatile species validated against the ACE tests under ex-vessel conditions.

  19. Measurement of reaction cross sections of fission products induced by DT neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Nakano, Daisuke; Murata, Isao; Takahashi, Akito [Osaka Univ., Suita (Japan)

    1998-03-01

    With the view of future application of fusion reactor to incineration of fission products, we have measured the {sup 129}I(n,2n){sup 128}I reaction cross section by DT neutrons with the activation method. The measured cross section was compared with the evaluated nuclear data of JENDL-3.2. From the result, it was confirmed that the evaluation overestimated the cross section by about 20-40%. (author)

  20. Separation Sr and Ba From Fission Products Using Sr-spec Resin Column

    Institute of Scientific and Technical Information of China (English)

    WANG; Xiu-feng

    2013-01-01

    Sr and Ba are the IIA group elements,with the same outer electronic structure,and the very similar properties,so separation of the two elements becomes very difficult.The traditional separation method of Sr and Ba in fission products is repeated precipitation of BaCl2·H2O in hydrochloric acid-ether medium.Four times repeated precipitation steps are needed to ensure the decontamination factor of Sr to be better

  1. Energy from nuclear fission an introduction

    CERN Document Server

    De Sanctis, Enzo; Ripani, Marco

    2016-01-01

    This book provides an overview on nuclear physics and energy production from nuclear fission. It serves as a readable and reliable source of information for anyone who wants to have a well-balanced opinion about exploitation of nuclear fission in power plants. The text is divided into two parts; the first covers the basics of nuclear forces and properties of nuclei, nuclear collisions, nuclear stability, radioactivity, and provides a detailed discussion of nuclear fission and relevant topics in its application to energy production. The second part covers the basic technical aspects of nuclear fission reactors, nuclear fuel cycle and resources, safety, safeguards, and radioactive waste management. The book also contains a discussion of the biological effects of nuclear radiation and of radiation protection, and a summary of the ten most relevant nuclear accidents. The book is suitable for undergraduates in physics, nuclear engineering and other science subjects. However, the mathematics is kept at a level that...

  2. FIssion Product Prompt γ-ray spectrometer: Development of an instrumented gas-filled magnetic spectrometer at the ILL

    Science.gov (United States)

    Blanc, A.; Chebboubi, A.; Faust, H.; Jentschel, M.; Kessedjian, G.; Köster, U.; Materna, T.; Panebianco, S.; Sage, C.; Urban, W.

    2013-12-01

    Accurate thermal neutron-induced fission data are important for applications in reactor physics as well as for fundamental nuclear physics. FIPPS is the new FIssion Product Prompt γ-ray Spectrometer being developed at the Institut Laue Langevin for neutron-induced fission studies. FIPPS is based on the combination of a large Germanium detector array surrounding a fission target, a Time-Of-Flight detector and a Gas-Filled Magnet (GFM) to identify mass, nuclear charge and kinetic energy of one of the fission fragments. The GFM will be instrumented with a Time-Projection Chamber (TPC) for individual 3D tracking of the fragments. A conceptual design study of the new spectrometer is presented.

  3. From EXILL (EXogam at the ILL to FIPPS (FIssion Product Prompt γ-ray Spectrometer

    Directory of Open Access Journals (Sweden)

    Blanc A.

    2015-01-01

    Full Text Available Within the EXILL campaign a large and efficient cluster of Ge-detectors was installed around a very well collimated neutron beam. This has allowed to carry out rather complete spectroscopic studies close to the line of stability using the (n,γ reaction. Neutron rich isotopes were produced by neutron induced fission and prompt spectroscopy was carried out. The isotope selection in this setup was based on a partially known level scheme and the use of triple coincidences. The latter is limiting the statistical sensitivity in the case of weak production yields. Based on the experiences of these campaigns we are currently developing a new setup: FIPPS (FIssion Product Prompt Spectroscopy. This setup combines a collimated neutron beam, a highly efficient cluster of Ge detectors, a gas filled magnet and auxiliary detectors. The presence of the gas filled magnet will allow us to identify fission products directly and should give access to a new quality of studies if compared to the EXILL campaign. The EXILL campaign and the FIPPS project are presented.

  4. Linear Free Energy Correlations for Fission Product Release from the Fukushima-Daiichi Nuclear Accident

    Energy Technology Data Exchange (ETDEWEB)

    Abrecht, David G.; Schwantes, Jon M.

    2015-03-03

    This paper extends the preliminary linear free energy correlations for radionuclide release performed by Schwantes, et al., following the Fukushima-Daiichi Nuclear Power Plant accident. Through evaluations of the molar fractionations of radionuclides deposited in the soil relative to modeled radionuclide inventories, we confirm the source of the radionuclides to be from active reactors rather than the spent fuel pool. Linear correlations of the form ln χ = -α (ΔGrxn°(TC))/(RTC)+β were obtained between the deposited concentration and the reduction potential of the fission product oxide species using multiple reduction schemes to calculate ΔG°rxn(TC). These models allowed an estimate of the upper bound for the reactor temperatures of TC between 2130 K and 2220 K, providing insight into the limiting factors to vaporization and release of fission products during the reactor accident. Estimates of the release of medium-lived fission products 90Sr, 121mSn, 147Pm, 144Ce, 152Eu, 154Eu, 155Eu, 151Sm through atmospheric venting and releases during the first month following the accident were performed, and indicate large quantities of 90Sr and radioactive lanthanides were likely to remain in the damaged reactor cores.

  5. Comparison of neutron cross sections for selected fission products and isotopic composition analyses with burnup

    Energy Technology Data Exchange (ETDEWEB)

    Kim, D. H.; Gil, C. S.; Kim, J. D.; Jang, J. H.; Lee, Y. D. [KAERI, Taejon (Korea)

    2003-10-01

    The neutron absorption cross sections for 18 fission products evaluated within the framework of the KAERI-BNL international collaboration have been compared with the ENDF/B-VI release 7. Also, the influence of the new evaluations on isotopic compositions of the fission products as a function of burnup has been analyzed through the OECD/NEA burnup credit criticality benchmarks (Phase 1B) and the LWR/Pu recycling benchmarks. These calculations were performed by WIMSD-5B with the 69 group libraries prepared from three evaluated nuclear data libraries: ENDF/B-VI.7, ENDF/B-VI.8 including new evaluations in resonance region covering thermal region, and ENDF/B-VII expected including those in upper resonance region up to 20 MeV. For Xe-131, the composition calculated with ENDF/B-VI.8 shows maximum difference of 4.78% compared to ENDF/B-VI.7. However, the isotopic compositions of all fission products calculated with ENDF/B-VII shows no differences compared to ENDF/B-VI.7.

  6. Comparisons of Neutron Cross Sections and Isotopic Composition Calculations for Fission-Product Evaluations

    Science.gov (United States)

    Kim, Do Heon; Gil, Choong-Sup; Chang, Jonghwa; Lee, Yong-Deok

    2005-05-01

    The neutron absorption cross sections for 18 fission products evaluated within the framework of the KAERI (Korea Atomic Energy Research Institute)-BNL (Brookhaven National Laboratory) international collaboration have been compared with ENDF/B-VI.7. Also, the influence of the new evaluations on the isotopic composition calculations of the fission products has been estimated through the OECD/NEA burnup credit criticality benchmarks (Phase 1B) and the LWR/Pu recycling benchmarks. These calculations were performed by WIMSD-5B with the 69-group libraries prepared from three evaluated nuclear data libraries: ENDF/B-VI.7, ENDF/B-VI.8 including the new evaluations in the resonance region covering the thermal region, and the expected ENDF/B-VII including those in the upper resonance region up to 20 MeV. For Xe-131, the composition calculated with ENDF/B-VI.8 shows a maximum difference of 5.02% compared to ENDF/B-VI.7. However, the isotopic compositions of all the fission products calculated with the expected ENDF/B-VII show no differences when compared to ENDF/B-VI.7 for the thermal reactor benchmark cases.

  7. Linear free energy correlations for fission product release from the Fukushima-Daiichi nuclear accident.

    Science.gov (United States)

    Abrecht, David G; Schwantes, Jon M

    2015-03-03

    This paper extends the preliminary linear free energy correlations for radionuclide release performed by Schwantes et al., following the Fukushima-Daiichi Nuclear Power Plant accident. Through evaluations of the molar fractionations of radionuclides deposited in the soil relative to modeled radionuclide inventories, we confirm the initial source of the radionuclides to the environment to be from active reactors rather than the spent fuel pool. Linear correlations of the form In χ = −α ((ΔGrxn°(TC))/(RTC)) + β were obtained between the deposited concentrations, and the reduction potentials of the fission product oxide species using multiple reduction schemes to calculate ΔG°rxn (TC). These models allowed an estimate of the upper bound for the reactor temperatures of TC between 2015 and 2060 K, providing insight into the limiting factors to vaporization and release of fission products during the reactor accident. Estimates of the release of medium-lived fission products 90Sr, 121mSn, 147Pm, 144Ce, 152Eu, 154Eu, 155Eu, and 151Sm through atmospheric venting during the first month following the accident were obtained, indicating that large quantities of 90Sr and radioactive lanthanides were likely to remain in the damaged reactor cores.

  8. Insights on fission products behaviour in nuclear severe accident conditions by X-ray absorption spectroscopy

    Science.gov (United States)

    Geiger, E.; Bès, R.; Martin, Ph; Pontillon, Y.; Ducros, G.; Solari, P. L.

    2016-04-01

    Many research programs have been carried out aiming to understand the fission products behaviour during a Nuclear Severe Accident. Most of these programs used highly radioactive irradiated nuclear fuel, which requires complex instrumentation. Moreover, the radioactive character of samples hinders an accurate chemical characterisation. In order to overcome these difficulties, SIMFUEL stand out as an alternative to perform complementary tests. A sample made of UO2 doped with 11 fission products was submitted to an annealing test up to 1973 K in reducing atmosphere. The sample was characterized before and after the annealing test using SEM-EDS and XAS at the MARS beam-line, SOLEIL Synchrotron. It was found that the overall behaviour of several fission products (such as Mo, Ba, Pd and Ru) was similar to that observed experimentally in irradiated fuels and consistent with thermodynamic estimations. The experimental approach presented in this work has allowed obtaining information on chemical phases evolution under nuclear severe accident conditions, that are yet difficult to obtain using irradiated nuclear fuel samples.

  9. Deposition of volatile fission products during commercial high-level waste vitrification

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, M.S.; Carter, J.G.

    1982-09-01

    High-level waste from spent commercial PWR fuel was vitrified during the Nuclear Waste Vitrification Project (NWVP), conducted at Pacific Northwest Laboratory in 1978 and 1979. The solidification equipment employed sintered metal filters and a conventional wet off-gas cleanup system to decontaminate the gases generated during waste processing. This report is a summary of a study completed under contract with U.S. Department of Energy (DOE) to determine the fate of volatile fission products in the filters and off-gas system. The study objectives were to determine (1) the extent of volatile fission product deposition within the sintered metal filters, (2) the distribution of fission products in the off-gas system, and (3) the factors that control the distribution. Such information is needed for the design and operation of future waste immobilization systems. The scope of the study included identification, preparation, and microprobe analyses of suitable filter samples and radiochemical analyses of off-gas system samples. The report describes the methods of sample selection and gathering, the analytical methods and results, and the interpretations of the results. Relationships to vitrification system operations are defined and operating conditions to minimize problems recommended. 37 figures, 14 tables.

  10. Fission Product Transport in TRISO Particle Layers under Operating and Off-Normal Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Van der Ven, Anton [Univ. of Michigan, Ann Arbor, MI (United States); Was, Gary [Univ. of Michigan, Ann Arbor, MI (United States); Wang, Lumin [Univ. of Michigan, Ann Arbor, MI (United States); Taheri, Mitra [Drexel Univ., Philadelphia, PA (United States)

    2014-04-26

    The objective of this project is to determine the diffusivity and chemical behavior of key fission products (ag, Cs, I. Te, Eu and Sr) through SiC and PyC both thermally, under irradiation, and under stress using FP introduction techniques that avoid the pitfalls of past experiments. The experimental approach is to create thin PyC-SiC couples containing the fission product to be studied embedded in the PyC layer. These samples will then be subjected to high temperature exposures in a vacuum and also to irradiation at high temperature, and last, to irradiation under stress at high temperature. The PyC serves as a host layer, providing a means of placing the fission product close to the SiC without damaging the SiC layer by its introduction or losing the FP during heating. Experimental measurements of grain boundary structure and distribution (EBSD, HRTEM, APT) will be used in the modeling effort to determine the qualitative dependence of FP diffusion coefficients on grain boundary orientation, temperature and stress.

  11. Photo-fission Product Yield Measurements at Eγ=13 MeV on 235U, 238U, and 239Pu

    Science.gov (United States)

    Tornow, W.; Bhike, M.; Finch, S. W.; Krishichayan, Fnu; Tonchev, A. P.

    2016-09-01

    We have measured Fission Product Yields (FPYs) in photo-fission of 235U, 238U, and 239Pu at TUNL's High-Intensity Gamma-ray Source (HI γS) using mono-energetic photons of Eγ = 13 MeV. Details of the experimental setup and analysis procedures will be discussed. Yields for approximately 20 fission products were determined. They are compared to neutron-induced FPYs of the same actinides at the equivalent excitation energies of the compound nuclear systems. In the future photo-fission data will be taken at Eγ = 8 . 0 and 10.5 MeV to find out whether photo-fission exhibits the same so far unexplained dependence of certain FPYs on the energy of the incident probe, as recently observed in neutron-induced fission, for example, for the important fission product 147Nd. Work supported by the U. S. Dept. of Energy, under Grant No. DE-FG02-97ER41033, and by the NNSA, Stewardship Science Academic Alliances Program, Grant No. DE-NA0001838 and the Lawrence Livermore, National Security, LLC under Contract No. DE-AC52-07NA27344.

  12. Neutron activation analysis (NAA), radioisotope production via neutron activation (PNA) and fission product gas-jet (GJA)

    Energy Technology Data Exchange (ETDEWEB)

    Gaeggeler, H.W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1996-11-01

    Three different non-diffractive applications of neutrons are outlined, neutron activation analysis, production of radionuclides, mostly for medical applications, and production of short-lived fission nuclides with a so-called gas-jet. It is shown that all three devices may be incorporated into one single insert at SINQ due to their different requests with respect to thermal neutron flux. Some applications of these three facilities are summarized. (author) 3 figs., 1 tab., 8 refs.

  13. Background for Terrestrial Antineutrino Investigations: Radionuclide Distribution, Georeactor Fission Events, and Boundary Conditions on Fission Power Production

    CERN Document Server

    Herndon, J M; Edgerley, Dennis A.

    2005-01-01

    Estimated masses of fissioning and non-fissioning radioactive elements and their respective distributions within the Earth are presented, based upon the fundamental identity of the components of the interior 82% of the Earth, the endo-Earth, with corresponding components of the Abee enstatite chondrite meteorite. Within limits of existing data, the following generalizations concerning the endo-Earth radionuclides can be made: (1) Most of the K-40 may be expected to exist in combination with oxygen in the silicates of the lower mantle, perhaps being confined to the upper region of the lower mantle where it transitions to the upper mantle; (2) Uranium may be expected to exist at the center of the Earth where it may undergo self-sustaining nuclear fission chain reactions, but there is a possibility that some non-fissioning uranium may be found scattered diffusely within the core floaters which are composed of CaS and MgS; and, (3) Thorium may be expected to occur within the core floaters at the core-mantle bound...

  14. Fission product yield distribution in the 12, 14, and 16 MeV bremsstrahlung-induced fission of {sup 232}Th

    Energy Technology Data Exchange (ETDEWEB)

    Naik, H. [Bhabha Atomic Research Centre, Radiochemistry Division, Mumbai (India); Kyungpook National University, Department of Physics and Center for High Energy Physics, Daegu (Korea, Republic of); Kim, G.N.; Kim, K. [Kyungpook National University, Department of Physics and Center for High Energy Physics, Daegu (Korea, Republic of); Schwengner, R.; John, R.; Massarczyk, R.; Junghans, A.; Wagner, A. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Goswami, A. [Bhabha Atomic Research Centre, Radiochemistry Division, Mumbai (India)

    2015-11-15

    The absolute cumulative yields of various fission products in the 12, 14, and 16 MeV bremsstrahlung-induced fission of {sup 232}Th were determined using a recoil catcher and an off-line γ -ray spectrometric technique using the ELBE electron linac of Helmholtz-Zentrum Dresden-Rossendorf in Dresden, Germany. The mass chain yields were obtained from the absolute cumulative yields by correcting the charge distribution. The peak-to-valley ratio, average light mass (left angle A{sub L} right angle) and heavy mass (left angle A{sub H} right angle) values, and average number of neutrons (left angle n right angle {sub exp}) in the bremsstrahlung-induced fission of {sup 232}Th at different excitation energies were obtained from the mass chain yield data. The present study and existing literature data for the {sup 232}Th(γ, f) reaction are compared with similar data for the {sup 238}U(γ, f) reaction at various excitation energies, and surprisingly different behavior was found in the two fissioning systems. (orig.)

  15. Fission-product energy release for times following thermal-neutron fission of /sup 235/U between 2 and 14000 seconds

    Energy Technology Data Exchange (ETDEWEB)

    Dickens, J.K.; Emery, J.F.; Love, T.A.; McConnell, J.W.; Northcutt, K.J.; Peelle, R.W.; Weaver, H.

    1977-10-01

    Fission-product decay energy-releases rates were measured for thermal-neutron fission of /sup 235/U. Samples of mass 1 to 10 ..mu..g were irradiated for 1 to 100 sec by use of the fast pneumatic-tube facility at the Oak Ridge Research Reactor. The resulting beta- and gamma-ray emissions were counted for times-after-fission between 2 and 14,000 seconds. The data were obtained for beta and gamma rays separately as spectral distributions, N(E/sub ..gamma../) vs E/sub ..gamma../ and N(E/sub beta/) vs E/sub ..beta../. For the gamma-ray data the spectra were obtained by using a NaI detector, while for the beta-ray data the spectra were obtained by using an NE-110 detector with an anticoincidence mantle. The raw data were unfolded to provide spectral distributions of modest resolution. These were integrated over E/sub ..gamma../ and E/sub ..beta../ to provide total yield and energy integrals as a function of time after fission. Results are low compared to the present 1973 ANS Decay-heat standard. A complete description of the experimental apparatus and data-reduction techniques is presented. The final integral data are given in tabular and graphical form and are compared with published data. 41 figures, 13 tables.

  16. Experimental investigations relevant for hydrogen and fission product issues raised by the Fukushima accident

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Sanjeev [Becker Technologies GmbH, Eschborn (Germany)

    2015-02-15

    The accident at Japan's Fukushima Daiichi nuclear power plant in March 2011, caused by an earthquake and a subsequent tsunami, resulted in a failure of the power systems that are needed to cool the reactors at the plant. The accident progression in the absence of heat removal systems caused Units 1-3 to undergo fuel melting. Containment pressurization and hydrogen explosions ultimately resulted in the escape of radioactivity from reactor containments into the atmosphere and ocean. Problems in containment venting operation, leakage from primary containment boundary to the reactor building, improper functioning of standby gas treatment system (SGTS), unmitigated hydrogen accumulation in the reactor building were identified as some of the reasons those added-up in the severity of the accident. The Fukushima accident not only initiated worldwide demand for installation of adequate control and mitigation measures to minimize the potential source term to the environment but also advocated assessment of the existing mitigation systems performance behavior under a wide range of postulated accident scenarios. The uncertainty in estimating the released fraction of the radionuclides due to the Fukushima accident also underlined the need for comprehensive understanding of fission product behavior as a function of the thermal hydraulic conditions and the type of gaseous, aqueous, and solid materials available for interaction, e.g., gas components, decontamination paint, aerosols, and water pools. In the light of the Fukushima accident, additional experimental needs identified for hydrogen and fission product issues need to be investigated in an integrated and optimized way. Additionally, as more and more passive safety systems, such as passive autocatalytic recombiners and filtered containment venting systems are being retrofitted in current reactors and also planned for future reactors, identified hydrogen and fission product issues will need to be coupled with the

  17. Disposition of plutonium-239 via production of fission molybdenum-99.

    Science.gov (United States)

    Mushtaq, A

    2011-04-01

    A heritage of physical consequences of the U.S.-Soviet arms race has accumulated, the weapons-grade plutonium (WPu), which will become excess as a result of the dismantlement of the nuclear weapons under the arms reduction agreements. Disposition of Pu has been proposed by mixing WPu with high-level radioactive waste with subsequent vitrification into large, highly radioactive glass logs or fabrication into mixed oxide fuel with subsequent irradiation in existing light water reactors. A potential option may be the production of medical isotope molybdenum-99 by using Pu-239 targets.

  18. Effects of microstructural constraints on the transport of fission products in uranium dioxide at low burnups

    Science.gov (United States)

    Lim, Harn Chyi; Rudman, Karin; Krishnan, Kapil; McDonald, Robert; Dickerson, Patricia; Gong, Bowen; Peralta, Pedro

    2016-08-01

    Diffusion of fission gases in UO2 is studied at low burnups, before bubble growth and coalescence along grain boundaries (GBs) become dominant, using a 3-D finite element model that incorporates actual UO2 microstructures. Grain boundary diffusivities are assigned based on crystallography with lattice and GB diffusion coupled with temperature to account for temperature gradients. Heterogeneity of GB properties and connectivity can induce regions where concentration is locally higher than without GB diffusion. These regions are produced by "bottlenecks" in the GB network because of lack of connectivity among high diffusivity GBs due to crystallographic constraints, and they can lead to localized swelling. Effective diffusivities were calculated assuming a uniform distribution of high diffusivity among GBs. Results indicate an increase over the bulk diffusivity with a clear grain size effect and that connectivity and properties of different GBs become important factors on the variability of fission product concentration at the microscale.

  19. Fundamental Studies of Irradiation-Induced Defect Formation and Fission Product Dynamics in Oxide Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Stubbins, James

    2012-12-19

    The objective of this research program is to address major nuclear fuels performance issues for the design and use of oxide-type fuels in the current and advanced nuclear reactor applications. Fuel performance is a major issue for extending fuel burn-up which has the added advantage of reducing the used fuel waste stream. It will also be a significant issue with respect to developing advanced fuel cycle processes where it may be possible to incorporate minor actinides in various fuel forms so that they can be 'burned' rather than join the used fuel waste stream. The potential to fission or transmute minor actinides and certain long-lived fission product isotopes would transform the high level waste storage strategy by removing the need to consider fuel storage on the millennium time scale.

  20. Measurement of tritium production rate distribution for a fusion-fission hybrid conceptual reactor

    Institute of Scientific and Technical Information of China (English)

    WANG Xin-Hua; GUO Hai-Ping; MOU Yun-Feng; ZHENG Pu; LIU Rong; YANG Xiao-Fei; YANG Jian

    2013-01-01

    A fusion-fission hybrid conceptual reactor is established.It consists of a DT neutron source and a spherical shell of depleted uranium and hydrogen lithium.The tritium production rate (TPR) distribution in the conceptual reactor was measured by DT neutrons using two sets of lithium glass detectors with different thicknesses in the hole in the vertical direction with respect to the D+ beam of the Cockcroft-Walton neutron generator in direct current mode.The measured TPR distribution is compared with the calculated results obtained by the threedimensional Monte Carlo code MCNP5 and the ENDF/B-Ⅵ data file.The discrepancy between the measured and calculated values can be attributed to the neutron data library of the hydrogen lithium lack S(α,β) thermal scattering model,so we show that a special database of low-energy and thermal neutrons should be established in the physics design of fusion-fission hybrid reactors.

  1. Isomer production ratios and the angular momentum distribution of fission fragments

    Science.gov (United States)

    Stetcu, I.; Talou, P.; Kawano, T.; Jandel, M.

    2013-10-01

    Latest generation fission experiments provide an excellent testing ground for theoretical models. In this contribution we compare the measurements for 235U(nth,f), obtained with the Detector for Advanced Neutron Capture Experiments (DANCE) calorimeter at Los Alamos Neutron Science Center (LANSCE), with our full-scale simulation of the primary fragment de-excitation, using the recently developed cgmf code, based on a Monte Carlo implementation of the Hauser-Feshbach theoretical model. We compute the isomer ratios as a function of the initial angular momentum of the fission fragments, for which no direct information exists. Comparison with the available experimental data allows us to determine the initial spin distribution. We also study the dependence of the isomer ratio on the knowledge of the low-lying discrete spectrum input for nuclear fission reactions, finding a high degree of sensitivity. Finally, in the same Hauser-Feshbach approach, we calculate the isomer production ratio for thermal neutron capture on stable isotopes, where the initial conditions (spin, excitation energy, etc.) are well understood. We find that with the current parameters involved in Hauser-Feshbach calculations, we obtain up to a factor of 2 deviation from the measured isomer ratios.

  2. Radioactive Ion Beam Production by Fast-Neutron-Induced Fission in Actinide Targets at EURISOL

    CERN Document Server

    Herrera-Martínez, Adonai

    The European Isotope Separation On-Line Radioactive Ion Beam Facility (EURISOL) is set to be the 'next-generation' European Isotope Separation On-Line (ISOL) Radioactive Ion Beam (RIB) facility. It will extend and amplify current research on nuclear physics, nuclear astrophysics and fundamental interactions beyond the year 2010. In EURISOL, the production of high-intensity RIBs of specific neutron-rich isotopes is obtained by inducing fission in large-mass actinide targets. In our contribution, the use of uranium targets is shown to be advantageous to other materials, such as thorium. Therefore, in order to produce fissions in U-238 and reduce the plutonium inventory, a fast neutron energy spectrum is necessary. The large beam power required to achieve these RIB levels requires the use of a liquid proton-to-neutron converter. This article details the design parameters of the converter, with special attention to the coupled neutronics of the liquid converter and fission target. Calculations performed with the ...

  3. Investigation of the Feasibility of Utilizing Gamma Emission Computed Tomography in Evaluating Fission Product Migration in Irradiated TRISO Fuel Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Jason M. Harp; Paul A. Demkowicz

    2014-10-01

    In the High Temperature Gas-Cooled Reactor (HTGR) the TRISO particle fuel serves as the primary fission product containment. However the large number of TRISO particles present in proposed HTGRs dictates that there will be a small fraction (~10-4 to 10-5) of as manufactured and in-pile particle failures that will lead to some fission product release. The matrix material surrounding the TRISO particles in fuel compacts and the structural graphite holding the TRISO particles in place can also serve as sinks for containing any released fission products. However data on the migration of solid fission products through these materials is lacking. One of the primary goals of the AGR-3/4 experiment is to study fission product migration from failed TRISO particles in prototypic HTGR components such as structural graphite and compact matrix material. In this work, the potential for a Gamma Emission Computed Tomography (GECT) technique to non-destructively examine the fission product distribution in AGR-3/4 components and other irradiation experiments is explored. Specifically, the feasibility of using the Idaho National Laboratory (INL) Hot Fuels Examination Facility (HFEF) Precision Gamma Scanner (PGS) system for this GECT application is considered. To test the feasibility, the response of the PGS system to idealized fission product distributions has been simulated using Monte Carlo radiation transport simulations. Previous work that applied similar techniques during the AGR-1 experiment will also be discussed as well as planned uses for the GECT technique during the post irradiation examination of the AGR-2 experiment. The GECT technique has also been applied to other irradiated nuclear fuel systems that were currently available in the HFEF hot cell including oxide fuel pins, metallic fuel pins, and monolithic plate fuel.

  4. Deposition of fission and activation products after the Fukushima Dai-ichi nuclear power plant accident.

    Science.gov (United States)

    Shozugawa, Katsumi; Nogawa, Norio; Matsuo, Motoyuki

    2012-04-01

    The Great Eastern Japan Earthquake on March 11, 2011, damaged reactor cooling systems at Fukushima Dai-ichi nuclear power plant. The subsequent venting operation and hydrogen explosion resulted in a large radioactive nuclide emission from reactor containers into the environment. Here, we collected environmental samples such as soil, plant species, and water on April 10, 2011, in front of the power plant main gate as well as 35 km away in Iitate village, and observed gamma-rays with a Ge(Li) semiconductor detector. We observed activation products ((239)Np and (59)Fe) and fission products ((131)I, (134)Cs ((133)Cs), (137)Cs, (110m)Ag ((109)Ag), (132)Te, (132)I, (140)Ba, (140)La, (91)Sr, (91)Y, (95)Zr, and (95)Nb). (239)Np is the parent nuclide of (239)Pu; (59)Fe are presumably activation products of (58)Fe obtained by corrosion of cooling pipes. The results show that these activation and fission products, diffused within a month of the accident.

  5. Implementation of a Thermodynamic Solver within a Computer Program for Calculating Fission-Product Release Fractions

    Science.gov (United States)

    Barber, Duncan Henry

    During some postulated accidents at nuclear power stations, fuel cooling may be impaired. In such cases, the fuel heats up and the subsequent increased fission-gas release from the fuel to the gap may result in fuel sheath failure. After fuel sheath failure, the barrier between the coolant and the fuel pellets is lost or impaired, gases and vapours from the fuel-to-sheath gap and other open voids in the fuel pellets can be vented. Gases and steam from the coolant can enter the broken fuel sheath and interact with the fuel pellet surfaces and the fission-product inclusion on the fuel surface (including material at the surface of the fuel matrix). The chemistry of this interaction is an important mechanism to model in order to assess fission-product releases from fuel. Starting in 1995, the computer program SOURCE 2.0 was developed by the Canadian nuclear industry to model fission-product release from fuel during such accidents. SOURCE 2.0 has employed an early thermochemical model of irradiated uranium dioxide fuel developed at the Royal Military College of Canada. To overcome the limitations of computers of that time, the implementation of the RMC model employed lookup tables to pre-calculated equilibrium conditions. In the intervening years, the RMC model has been improved, the power of computers has increased significantly, and thermodynamic subroutine libraries have become available. This thesis is the result of extensive work based on these three factors. A prototype computer program (referred to as SC11) has been developed that uses a thermodynamic subroutine library to calculate thermodynamic equilibria using Gibbs energy minimization. The Gibbs energy minimization requires the system temperature (T) and pressure (P), and the inventory of chemical elements (n) in the system. In order to calculate the inventory of chemical elements in the fuel, the list of nuclides and nuclear isomers modelled in SC11 had to be expanded from the list used by SOURCE 2.0. A

  6. Etude de la production de fragments dans la fission induite par neutrons sur l'uranium 238.

    CERN Document Server

    Casoli, P

    2003-01-01

    Mass and charge distributions of fission fragments from the fission induced on uranium 238 by neutrons from 1 to 150 MeV were studied by experimental data and theoretical calculations. Measurements in prompt gamma and x-ray spectroscopy, completed at the LANSCE laboratory of Los Alamos allowed us to determine the secondary fission fragment production yields. Photovoltaic cells were used as a fission trigger. About one hundred fragments were identified and about thirty excitation functions were extracted. Mass and charge distributions at different incident energies were obtained. The comparison with evaluated data (Wahl systematics) shows that the calculations are consistent with the measurements below 20 MeV but not predictive enough above. A potential energy surface was drawn from microscopic constrained self-consistent HFB calculations. We obtained a fragment mass distribution by solving the dynamic Schrodinger equation on this surface.

  7. Measurement of the isomeric yield ratios of fission products with JYFLTRAP

    CERN Document Server

    Gorelov, D; Hakala, J; Jokinen, A; Kolhinen, V S; Koponen, J; Lantz, M; Matteram, A; Moore, I; Penttilä, H; Pohjalainen, I; Pomp, S; Rakopoulos, V; Reponen, M; Rinta-Antilav, S; Schonnenschein, V; Simutkin, V; Solders, A; Voss, A; Äystö, J

    2014-01-01

    Several isomeric yield ratios of fission products in 25 MeV pr oton-induced fis- sion of 238 U were measured recently at the JYFLTRAP facility. The ion-g uide separator on-line method was utilized to produce radioacti ve ions. The dou- ble Penning-trap mass spectrometer was used to separate iso meric and ground states by their masses. To verify the new experimental techn ique γ -spectro- scopy method was used to obtain the same isomeric ratios.

  8. Gamma emitting fission products in surface sediments of the Ravenglass estuary

    Energy Technology Data Exchange (ETDEWEB)

    Aston, S.R.; Stanners, D.A. (Lancaster Univ. (UK))

    1982-04-01

    The occurrence of some fission products from the Sellafield (formerly Windscale) nuclear fuel reprocessing facility has been determined for surface sediments from forty locations in the Ravenglass estuary, North-West England. The influence of the silt-sized fraction in the sediments on the geographic distribution of /sup 137/Cs is clearly important, and to a lesser extent also influences the distributions of /sup 106/Ru, /sup 134/Cs + /sup 95/Zr/Nb and /sup 144/Ce. The data are compared with recently published results reported by the Ministry of Agriculture, Fisheries and Food for a monitoring site in this estuary.

  9. Study of Rapid Radiochemical Separation of 90Rb from Fission Product

    Institute of Scientific and Technical Information of China (English)

    YUE; Yuan-zhen; MAO; Guo-shu; YANG; Lei; DING; You-qian; MA; Peng

    2015-01-01

    90Rb is a high yield and short-lived fission product,and it is a sensitive monitor at low burnup.The decay data of 90Rb are important,however the uncertainty of the decay data of 90Rb tends to be large,such as the half-life data(58±5)s(with an uncertainty of 3.2%)from ENSDF.In order to get the half-life measured more accurately,a carrier-free 90Rb sample of

  10. Transport of fission products with a helium gas-jet at TRIGA-SPEC

    Energy Technology Data Exchange (ETDEWEB)

    Eibach, M., E-mail: martin.eibach@uni-mainz.d [Institut fuer Kernchemie, Johannes Gutenberg-Universitaet Mainz, Fritz-Strassmann-Weg 2, 55128 Mainz (Germany); Physikalisches Institut, Ruprecht-Karls-Universitaet Heidelberg, Philosophenweg 12, 69120 Heidelberg (Germany); Beyer, T.; Blaum, K. [Physikalisches Institut, Ruprecht-Karls-Universitaet Heidelberg, Philosophenweg 12, 69120 Heidelberg (Germany); Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Block, M. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Planckstrasse 1, 64291 Darmstadt (Germany); Eberhardt, K. [Institut fuer Kernchemie, Johannes Gutenberg-Universitaet Mainz, Fritz-Strassmann-Weg 2, 55128 Mainz (Germany); Herfurth, F. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Planckstrasse 1, 64291 Darmstadt (Germany); Geppert, C. [Institut fuer Kernchemie, Johannes Gutenberg-Universitaet Mainz, Fritz-Strassmann-Weg 2, 55128 Mainz (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Planckstrasse 1, 64291 Darmstadt (Germany); Ketelaer, J. [Institut fuer Physik, Johannes Gutenberg-Universitaet Mainz, Staudinger Weg 7, 55128 Mainz (Germany); Ketter, J. [Physikalisches Institut, Ruprecht-Karls-Universitaet Heidelberg, Philosophenweg 12, 69120 Heidelberg (Germany); Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Kraemer, J.; Krieger, A. [Institut fuer Kernchemie, Johannes Gutenberg-Universitaet Mainz, Fritz-Strassmann-Weg 2, 55128 Mainz (Germany); Knuth, K. [Institut fuer Physik, Johannes Gutenberg-Universitaet Mainz, Staudinger Weg 7, 55128 Mainz (Germany); Nagy, Sz. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Planckstrasse 1, 64291 Darmstadt (Germany)

    2010-02-01

    A helium gas-jet system for the transport of fission products from the research reactor TRIGA Mainz has been developed, characterized and tested within the TRIGA-SPEC experiment. For the first time at TRIGA Mainz carbon aerosol particles have been used for the transport of radionuclides from a target chamber with high efficiency. The radionuclides have been identified by means of gamma-spectroscopy. Transport time, efficiency as well as the absolute number of transported radionuclides for several species have been determined. The design and the characterization of the gas-jet system are described and discussed.

  11. Fission product release phenomena during core melt accidents in metal fueled heavy water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Ellison, P G; Hyder, M L; Monson, P R; Randolph, H W [Westinghouse Savannah River Co., Aiken, SC (USA); Hagrman, D L [EG and G Idaho, Inc., Idaho Falls, ID (USA); McClure, P R; Leonard, M T [Science Applications International Corp., Albuquerque, NM (USA)

    1990-01-01

    The phenomena that determine fission product release rates from a core melting accident in a metal-fueled, heavy water reactor are described in this paper. This information is obtained from the analysis of the current metal fuel experimental data base and from the results of analytical calculations. Experimental programs in place at the Savannah River Site are described that will provide information to resolve uncertainties in the data base. The results of the experiments will be incorporated into new severe accident computer codes recently developed for this reactor design. 47 refs., 4 figs.

  12. Neutron capture cross-section of fission products in the European activation file EAF-3

    Energy Technology Data Exchange (ETDEWEB)

    Kopecky, J.; Delfini, M.G.; Kamp, H.A.J. van der; Gruppelaar, H.; Nierop, D. (Netherlands Energy Research Foundation (ECN), Petten (Netherlands))

    1992-05-01

    This paper contains a description of the work performed to extend and revise the neutron capture data in the European Activation File (EAF-3) with emphasis on nuclides in the fission-product mass range. The starter was the EAF-1 data file from 1989. The present version, EAF/NG-3, contains (n,[gamma]) excitation functions for all nuclides (729 targets) with half-lives exceeding 1/2 day in the mass range from H-1 to Cm-248. The data file is equipped with a preliminary uncertainty file, that will be improved in the near future. (author). 19 refs.; 5 figs.; 3 tabs.

  13. Investigation of Adsorption Behavior of Ba and Other Fission Products on the Sr·spc Chromatographic Column by Static Method

    Institute of Scientific and Technical Information of China (English)

    YANG; Lei; MA; Peng; YANG; Su-liang; LIANG; Xiao-hu

    2012-01-01

    <正>Adsorption behavior of Ba, Cs and some other fission products on the Sr·spc resin has been investigated for the purpose of extracting 141Ba from the fission product. Sr·spc resin with the main functional group of 18-crown-6 ether was purchased from US. Eichrom Company. Tracers of Ba, Cs and some other fission products were acquired from an irradiated U target.

  14. Monte Carlo Models for the Production of beta-delayed Gamma Rays Following Fission of Special Nuclear Materials

    Energy Technology Data Exchange (ETDEWEB)

    Pruet, J; Prussin, S; Descalle, M; Hall, J

    2004-02-03

    A Monte Carlo method for the estimation of {beta}-delayed {gamma}-ray spectra following fission is described that can accommodate an arbitrary time-dependent fission rate and photon collection history. The method invokes direct sampling of the independent fission yield distributions of the fissioning system, the branching ratios for decay of individual fission products and the spectral distributions for photon emission for each decay mode. Though computationally intensive, the method can provide a detailed estimate of the spectrum that would be recorded by an arbitrary spectrometer, and can prove useful in assessing the quality of evaluated data libraries, for identifying gaps in these libraries, etc. The method is illustrated by a first comparison of calculated and experimental spectra from decay of short-lived fission products following the reactions {sup 235}U(n{sub th}, f) and {sup 239}Pu(n{sub th}, f). For general purpose transport calculations, where detailed consideration of the large number of individual {gamma}-ray transitions in a spectrum may be unnecessary, it is shown that an accurate and simple parameterization of a {gamma}-ray source function can be obtained. These parametrizations should provide high-quality average spectral distributions that should prove useful in calculations describing photons escaping from thick attenuating media.

  15. [Medical equipment product lines in basic pharmacies].

    Science.gov (United States)

    Macesková, B; Lipská, J

    2003-07-01

    Medical appliances dispensed in basic type pharmacies for cash or vouchers for medical or orthopedic appliances require expertise of pharmacists and laboratory assistants concerning the assortment, payment, construction of prices, conditions for prescription, ordering, properties, and functions of individual appliances. Using the method of frequency analysis, the analysis of data from five pharmacies within a period of three months (more than 17,000 records) revealed how individual subgroups of medical appliances and their concrete items are represented in both types of dispensation. The method of the semistructured questionnaire (10 respondents) was used to find what problems are encountered in dispensation, and which medical appliances and their subgroups are the sources of the problems. The respondents regard the contemporary level of knowledge concerning medical appliances gained in pregradual studies as insufficient.

  16. Chemical thermodynamics of Cs and Te fission product interactions in irradiated LMFBR mixed-oxide fuel pins

    Science.gov (United States)

    Adamson, M. G.; Aitken, E. A.; Lindemer, T. B.

    1985-02-01

    A combination of fuel chemistry modelling and equilibrium thermodynamic calculations has been used to predict the atom ratios of Cs and Te fission products (Cs:Te) that find their way into the fuel-cladding interface region of irradiated stainless steel-clad mixed-oxide fast breeder reactor fuel pins. It has been concluded that the ratio of condensed, chemically-associated Cs and Te in the interface region,Čs:Te, which in turn determines the Te activity, is controlled by an equilibrium reaction between Cs 2Te and the oxide fuel, and that the value of Čs:Te is, depending on fuel 0:M, either equal to or slightly less than 2:1. Since Cs and Te fission products are both implicated as causative agents in FCCI (fission product-assisted inner surface attack of stainless steel cladding) and in FPLME (fission product-assisted liquid metal embrittlement of AISI-Type 316), the observed out-of-pile Cs:Te thresholds for FCCI (4˜:1) and FPLME (2˜:1) have been rationalized in terms of Cs:Te thermochemistry and phase equilibria. Also described in the paper is an updated chemical evolution model for reactive/volatile fission product behavior in irradiated oxide pins.

  17. Production and study of fission fragments, from Lohengrin to Alto; Production et etude des fragments de fission, de Lohengrin a Alto

    Energy Technology Data Exchange (ETDEWEB)

    Ibrahim, F

    2005-06-15

    The study of nuclei far from stability is constitutive of the history of nuclear physics at its very beginning and has been making considerable great strides since then. The study of these nuclei give the opportunity to reach new information on the nuclear structure and thus to measure the solidity of our knowledge on nuclear matter and its validity when it is pushed to its limits. The reaction selected for the production of exotic nuclei in the framework of the PARRNe program is the fission of uranium 238. The nuclei produced have an intermediate mass and are very rich in neutrons. The technique to recover them in order to accelerate them is the thick target method called also the Isol technique. The installation of the ancient Lep injector at the Tandem line in Orsay (IPN) is expected to increase by a factor 100 the production rate of exotic nuclei in the PARRNe program, it is the Alto project. The work presented here concerns studies carried out at the Lohengrin spectrometer installed at the ILL in Grenoble, and at the Tandem installation in Orsay. This document is divided into 4 parts: 1) in flight techniques at Lohengrin, 2) the Isol technique, 3) magic numbers in the domain N=50, and 4) the Alto project.

  18. Energy from nuclear fission(*

    Directory of Open Access Journals (Sweden)

    Ripani M.

    2015-01-01

    Full Text Available The main features of nuclear fission as physical phenomenon will be revisited, emphasizing its peculiarities with respect to other nuclear reactions. Some basic concepts underlying the operation of nuclear reactors and the main types of reactors will be illustrated, including fast reactors, showing the most important differences among them. The nuclear cycle and radioactive-nuclear-waste production will be also discussed, along with the perspectives offered by next generation nuclear assemblies being proposed. The current situation of nuclear power in the world, its role in reducing carbon emission and the available resources will be briefly illustrated.

  19. Airborne measurements of fission product fall-out. An investigation of possibilities and problems

    Energy Technology Data Exchange (ETDEWEB)

    Hovgaard, J.; Korsbech, U.

    1992-12-01

    During 1993 the Danish Emergency Management Agency will install an airborne {gamma}-ray detector system for area survey of contamination with radioactive nuclides - primarily fission products that may be released during a heavy accident at a nuclear power plant or from accidents during transport of radioactive material. The equipment is based on 16 liter NaI(TI) crystals and multichannel analysers from Exploranium (Canada). A preliminary investigation of the possibilities for detection of low and high level contamination - and the problems that may be expected during use of the equipment, and during interpretation of the measured data, is described. Several days after reactor shut-down some of the nuclides can be identified directly from the measured spectrum, and contamination levels may be determined within a factor two. After several weeks, most fission products have decayed. Concentrations and exposure rates can be determined with increasing accuracy as time passes. Approximate calibration of the equipment for measurements of surface contamination and natural radioactivity can be performed in the laboratory. Further checks of equipment should include accurate measurements of the spectrum resolution. Detectors should be checked individually, and all together. Further control of dead time and pulse pile-up should be performed. Energy calibration, electronics performance and data equipment should be tested against results from the original calibration. (AB).

  20. Distribution of fission products in Peach Bottom HTGR fuel element E11-07

    Energy Technology Data Exchange (ETDEWEB)

    Wichner, R.P.; Dyer, F.F.; Martin, W.J.; Bate, L.C.

    1977-04-01

    This is the second in a projected series of six post-irradiation examinations of Peach Bottom High-Temperature Gas-Cooled Reactor driver fuel elements. Element E11-07, the subject of this report, received an equivalent of 701 full-power days of irradiation prior to scheduled withdrawal. The examination procedures emphasized the determination of fission product distributions in the graphite portions of the fuel element. Continuous axial scans indicated a /sup 137/Cs inventory of 17 Ci in the graphite sleeve and 8.3 Ci in the spine at the time of element withdrawal from the core. In addition, the nuclides /sup 134/Cs, /sup 110m/Ag, /sup 60/Co, and /sup 154/Eu were found in the graphite portions of the fuel element in significant amounts. Radial distributions of these nuclides plus the distribution of the beta emitters /sup 3/H, /sup 14/C, and /sup 90/Sr were obtained at six axial locations, four within the fueled region and one each above and below. The radial dissection was accomplished by use of a manipulator-operated lathe in a hot cell. These profiles reveal an increased degree of penetration of /sup 134/Cs, relative to /sup 137/Cs, evidently due to a longer time spent as xenon precursor. In addition to fission product distribution, the appearance of the element components was recorded photographically, fuel compact and graphite dimensions were recorded at numerous locations, and metallographic examinations of the fuel were performed.

  1. Influence of SiC grain boundary character on fission product transport in irradiated TRISO fuel

    Science.gov (United States)

    Lillo, T. M.; van Rooyen, I. J.

    2016-05-01

    In this study, the fission product precipitates at silicon carbide grain boundaries from an irradiated TRISO particle were identified and correlated with the associated grain boundary characteristics. Precession electron diffraction in the transmission electron microscope provided the crystallographic information needed to identify grain boundary misorientation and boundary type (i.e., low angle, random high angle or coincident site lattice (CSL)-related). The silicon carbide layer was found to be composed mainly of twin boundaries and small fractions of random high angle and low angle grain boundaries. Most fission products were found at random, high-angle grain boundaries, with small fractions at low-angle and CSL-related grain boundaries. Palladium (Pd) was found at all types of grain boundaries while Pd-uranium and Pd-silver precipitates were only associated with CSL-related and random, high-angle grain boundaries. Precipitates containing only Ag were found only at random, high-angle grain boundaries, but not at low angle or CSL-related grain boundaries.

  2. Breast cancer: evidence for a relation to fission products in the diet.

    Science.gov (United States)

    Sternglass, E J; Gould, J M

    1993-01-01

    To establish the possible relation between breast cancer mortality and low doses of radiation due to fission products in the environment, the mortality rates in the nine census regions of the United States for the years 1984-1988 were correlated with the cumulative airborne releases from all the nuclear plants in each region for the period 1970-1987. A high correlation coefficient of 0.91 was obtained for a logarithmic dependence on the total releases, consistent with an indirect action via free-radical oxygen at very low dose rates, in contrast to a direct action on DNA at high dose rates, explaining the wide differences in risk per unit dose obtained in earlier studies. The recent temporal changes of breast cancer rates in the New York metropolitan area including nearby Connecticut, Westchester, and Long Island were examined in relation to the releases from nearby nuclear plants and found to be consistent with a dominant role of short-lived fission products in drinking water and fresh milk. The results support a major role for nuclear plant releases in industrial countries in the recent rises of breast and other forms of cancers not related to smoking, especially among older persons, and strongly support the need to replace nuclear reactors with more benign ways to generate electricity.

  3. Fission Product Monitoring of TRISO Coated Fuel For The Advanced Gas Reactor -1 Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Dawn M. Scates; John (Jack) K Hartwell; John B. Walter

    2008-09-01

    The US Department of Energy has embarked on a series of tests of TRISO-coated particle reactor fuel intended for use in the Very High Temperature Reactor (VHTR) as part of the Advanced Gas Reactor (AGR) program. The AGR-1 TRISO fuel experiment, currently underway, is the first in a series of eight fuel tests planned for irradiation in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The AGR-1 experiment reached a peak compact averaged burn up of 9% FIMA with no known TRISO fuel particle failures in March 2008. The burnup goal for the majority of the fuel compacts is to have a compact averaged burnup greater than 18% FIMA and a minimum compact averaged burnup of 14% FIMA. At the INL the TRISO fuel in the AGR-1 experiment is closely monitored while it is being irradiated in the ATR. The effluent monitoring system used for the AGR-1 fuel is the Fission Product Monitoring System (FPMS). The FPMS is a valuable tool that provides near real-time data indicative of the AGR-1 test fuel performance and incorporates both high-purity germanium (HPGe) gamma-ray spectrometers and sodium iodide [NaI(Tl)] scintillation detector-based gross radiation monitors. To quantify the fuel performance, release-to-birth ratios (R/B’s) of radioactive fission gases are computed. The gamma-ray spectra acquired by the AGR-1 FPMS are analyzed and used to determine the released activities of specific fission gases, while a dedicated detector provides near-real time count rate information. Isotopic build up and depletion calculations provide the associated isotopic birth rates. This paper highlights the features of the FPMS, encompassing the equipment, methods and measures that enable the calculation of the release-to-birth ratios. Some preliminary results from the AGR-1 experiment are also presented.

  4. The Fission-Based  99Mo Production Process ROMOL-99 and Its Application to PINSTECH Islamabad

    Directory of Open Access Journals (Sweden)

    Rudolf Muenze

    2013-01-01

    Full Text Available An innovative process for fission based 99Mo production has been developed under Isotope Technologies Dresden (ITD GmbH (former Hans Wälischmiller GmbH (HWM, Branch Office Dresden, and its functionality has been tested and proved at the Pakistan Institute of Nuclear Science and Technology (PINSTECH, Islamabad. Targets made from uranium aluminum alloy clad with aluminum were irradiated in the core of Pakistan Research Reactor-1 (PARR-1. In the mean time more than 50 batches of fission molybdenum-99 (99Mo have been produced meeting the international purity/pharmacopoeia specifications using this ROMOL-99 process. The process is based on alkaline dissolution of the neutron irradiated targets in presence of NaNO3, chemically extracting the 99Mo from various fission products and purifying the product by column chromatography. This ROMOL-99 process will be described in some detail.

  5. Fission product inventory for CANFLEX-NU and CANFLEX-RU in the limiting channel of CANDU

    Energy Technology Data Exchange (ETDEWEB)

    Park, Joo Hwan; Jung, Jong Yeob

    2007-09-15

    The fission product inventory was evaluated for the 37-element fuel, CANFLEX-NU and CANFLEX-RU fuels which irradiated in the assumed limiting O6{sub m}od channel under a normal operating condition. Generally, the assessment of fission product release is divided into 3 steps which are a calculation of FGR during steady state, a calculation of a prompt release at the time of an accident, and a calculation of delayed release after the accident. Among them the first step was described in this report. The analysis was performed by using the ELESTRES code which is a computer code used in a performance evaluation of the fuel bundle during the normal irradiation. The calculation results of the fission product inventory for the 37-element fuel, CANFLEX-NU and CANFLEX-RU were compared to each other.

  6. Fission Product Release and Survivability of UN-Kernel LWR TRISO Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Besmann, Theodore M [ORNL; Ferber, Mattison K [ORNL; Lin, Hua-Tay [ORNL

    2014-01-01

    A thermomechanical assessment of the LWR application of TRISO fuel with UN kernels was performed. Fission product release under operational and transient temperature conditions was determined by extrapolation from range calculations and limited data from irradiated UN pellets. Both fission recoil and diffusive release were considered and internal particle pressures computed for both 650 and 800 m diameter kernels as a function of buffer layer thickness. These pressures were used in conjunction with a finite element program to compute the radial and tangential stresses generated with a TRISO particle as a function of fluence. Creep and swelling of the inner and outer pyrolytic carbon layers were included in the analyses. A measure of reliability of the TRISO particle was obtained by measuring the probability of survival of the SiC barrier layer and the maximum tensile stress generated in the pyrolytic carbon layers as a function of fluence. These reliability estimates were obtained as functions of the kernel diameter, buffer layer thickness, and pyrolytic carbon layer thickness. The value of the probability of survival at the end of irradiation was inversely proportional to the maximum pressure.

  7. Towards high-precision mass measurements of neutron-rich fission products at TRIGA-SPEC

    Energy Technology Data Exchange (ETDEWEB)

    Nagy, Szilard [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany)

    2010-07-01

    TRIGA-TRAP, the only Penning trap mass spectrometer worldwide at a nuclear research reactor, is installed at TRIGA Mainz as part of the TRIGA-SPEC experiment. The scientific goal is to perform high-precision mass measurements on lanthanoids, actinoids and neutron-rich fission products produced by thermal neutron induced fission of a target inside the reactor. High-precision mass data are scarce in this region of the nuclear chart, and further experimental data are needed for nuclear structure studies of heavy elements, to test the predictive power of nuclear mass models, or as input to nucleosynthesis calculations of the astrophysical r-process. Ions of certain lanthanoids and most actinoids as well as carbon clusters for calibration purposes can be routinely produced by a newly developed non-resonant laser ablation ion source, allowing off-line mass measurements. Besides fundamental research, TRIGA-TRAP serves as a test bench for the development of efficient ion detection techniques, which will enable mass measurements ultimately on a single ion with a half-life of the order of one second. To this end, a unique combination of the commonly used time-of-flight technique and the non-destructive image current detection method is realized in an on-line mass spectrometer. The first mass measurement results are reported.

  8. New antineutrino energy spectra predictions from the summation of beta decay branches of the fission products.

    Science.gov (United States)

    Fallot, M; Cormon, S; Estienne, M; Algora, A; Bui, V M; Cucoanes, A; Elnimr, M; Giot, L; Jordan, D; Martino, J; Onillon, A; Porta, A; Pronost, G; Remoto, A; Taín, J L; Yermia, F; Zakari-Issoufou, A-A

    2012-11-16

    In this Letter, we study the impact of the inclusion of the recently measured beta decay properties of the (102;104;105;106;107)Tc, (105)Mo, and (101)Nb nuclei in an updated calculation of the antineutrino energy spectra of the four fissible isotopes (235,238)U and (239,241)Pu. These actinides are the main contributors to the fission processes in pressurized water reactors. The beta feeding probabilities of the above-mentioned Tc, Mo, and Nb isotopes have been found to play a major role in the γ component of the decay heat of (239)Pu, solving a large part of the γ discrepancy in the 4-3000 s range. They have been measured by using the total absorption technique, insensitive to the pandemonium effect. The calculations are performed by using the information available nowadays in the nuclear databases, summing all the contributions of the beta decay branches of the fission products. Our results provide a new prediction of the antineutrino energy spectra of (235)U, (239,241)Pu, and, in particular, (238)U for which no measurement has been published yet. We conclude that new total absorption technique measurements are mandatory to improve the reliability of the predicted spectra.

  9. New antineutrino energy spectra predictions from the summation of beta decay branches of the fission products

    CERN Document Server

    Fallot, M; Estienne, M; Algora, A; Bui, V M; Cucoanes, A; Elnimr, M; Giot, L; Jordan, D; Martino, J; Onillon, A; Porta, A; Pronost, G; Taín, J L; Yermia, F; Zakari-Issoufou, A -A

    2012-01-01

    In this paper, we study the impact of the inclusion of the recently measured beta decay properties of the $^{102;104;105;106;107}$Tc, $^{105}$Mo, and $^{101}$Nb nuclei in an updated calculation of the antineutrino energy spectra of the four fissible isotopes $^{235, 238}$U, and $^{239,241}$Pu. These actinides are the main contributors to the fission processes in Pressurized Water Reactors. The beta feeding probabilities of the above-mentioned Tc, Mo and Nb isotopes have been found to play a major role in the $\\gamma$ component of the decay heat of $^{239}$Pu, solving a large part of the $\\gamma$ discrepancy in the 4 to 3000\\,s range. They have been measured using the Total Absorption Technique (TAS), avoiding the Pandemonium effect. The calculations are performed using the information available nowadays in the nuclear databases, summing all the contributions of the beta decay branches of the fission products. Our results provide a new prediction of the antineutrino energy spectra of $^{235}$U, $^{239,241}$Pu ...

  10. A Research Program for Fission Product/Dust Transport in HTGR’s

    Energy Technology Data Exchange (ETDEWEB)

    Loyalka, Sudarshan [Univ. of Missouri, Columbia, MO (United States)

    2016-02-01

    High and Very High Temperatures Gas Reactors (HTGRs/VHTRs) have five barriers to fission product (FP) release: the TRISO fuel coating, the fuel elements, the core graphite, the primary coolant system, and the reactor building. This project focused on measurements and computations of FP diffusion in graphite, FP adsorption on graphite and FP interactions with dust particles of arbitrary shape. Diffusion Coefficients of Cs and Iodine in two nuclear graphite were obtained by the release method and use of Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) and Instrumented Neutron Activation Analysis (INAA). A new mathematical model for fission gas release from nuclear fuel was also developed. Several techniques were explored to measure adsorption isotherms, notably a Knudsen Effusion Mass Spectrometer (KEMS) and Instrumented Neutron Activation Analysis (INAA). Some of these measurements are still in progress. The results will be reported in a supplemental report later. Studies of FP interactions with dust and shape factors for both chain-like particles and agglomerates over a wide size range were obtained through solutions of the diffusion and transport equations. The Green's Function Method for diffusion and Monte Carlo technique for transport were used, and it was found that the shape factors are sensitive to the particle arrangements, and that diffusion and transport of FPs can be hindered. Several journal articles relating to the above work have been published, and more are in submission and preparation.

  11. Fission-product yields for thermal-neutron fission of /sup 243/Cm determined from measurements with a high-resolution low-energy germanium gamma-ray detector

    Energy Technology Data Exchange (ETDEWEB)

    Merriman, L.D.

    1984-04-01

    Cumulative fission-product yields have been determined for 13 gamma rays emitted during the decay of 12 fission products created by thermal-neutron fission of /sup 243/Cm. A high-resolution low-energy germanium detector was used to measure the pulse-height spectra of gamma rays emitted from a 77-nanogram sample of /sup 243/Cm after the sample had been irradiated by thermal neutrons. Analysis of the data resulted in the identification and matching of gamma-ray energies and half-lives to individual radioisotopes. From these results, 12 cumulative fission product yields were deduced for radionuclides with half-lives between 4.2 min and 84.2 min. 7 references.

  12. A Study on Fission Product Behavior during a Severe Accident at APR1400 Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Han-Chul [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of); Cho, Song-Won [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    In this study, calculations have been carried out for a SBO sequence similar to the selected scenario, but a faster one with simple assumptions. Instead, a sensitivity study was carried out to take into account the effects of such differences on the fission product behavior. Probabilistic Safety Assessment (PSA) for Shin-Kori 3·4 nuclear power plants, which are APR1400 type reactors, were reviewed. After all, the representing scenarios were determined to be the sequences with station blackout (SBO), interfacing system LOCA (ISLOCA), and steam generator tube rupture (SGTR), which are similar to those of the U.S.NRC's State-of-the-Art Reactor Consequence Analyses (SOARCA) study. Among those sequences, SBO occupies the largest portion of the risk from severe accidents, and was selected to be analyzed at first about the fission product behavior in the containment. It includes events such as failure of the alternative AC power generator following a blackout event, successful operation of turbine-driven auxiliary feed water (AFW) pump, late recovery of offsite power before containment failure, in-vessel injection and successful actuation of cavity flooding system and spray system, and failure of hydrogen mitigation system. We use MELCOR 1.8.6 with the 35- and 2-cell compartment models of the containment. Since MELCOR does not treat organic iodide, we tried to make the results up by MELCOR-RAIM which is the MELCOR code coupled with RAIM, a stand-alone code developed for evaluation of the iodine behavior. In order to investigate the fission product behavior during a severe accident at APR1400, we have selected the representing scenarios with SBO, ISLOCA and SGTR. Among them, a SBO sequence similar to the selected scenario, but a faster one with simple assumptions, was analyzed using MELCOR v1.8.6 with 35-cell models of the containment. For the sensitivity analysis, we use the 2-cell containment model and the codes with the iodine chemistry model such as MELCOR with

  13. Delayed fission

    Energy Technology Data Exchange (ETDEWEB)

    Hatsukawa, Yuichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-07-01

    Delayed fission is a nuclear decay process that couples {beta} decay and fission. In the delayed fission process, a parent nucleus undergoes {beta} decay and thereby populates excited states in the daughter. If these states are of energies comparable to or greater than the fission barrier of the daughter, then fission may compete with other decay modes of the excited states in the daughter. In this paper, mechanism and some experiments of the delayed fission will be discussed. (author)

  14. Laboratory-Scale Bismuth Phosphate Extraction Process Simulation To Track Fate of Fission Products

    Energy Technology Data Exchange (ETDEWEB)

    Serne, R. JEFFREY; Lindberg, Michael J.; Jones, Thomas E.; Schaef, Herbert T.; Krupka, Kenneth M.

    2007-02-28

    Recent field investigation that collected and characterized vadose zone sediments from beneath inactive liquid disposal facilities at the Hanford 200 Areas show lower than expected concentrations of a long-term risk driver, Tc-99. Therefore laboratory studies were performed to re-create one of the three processes that were used to separate the plutonium from spent fuel and that created most of the wastes disposed or currently stored in tanks at Hanford. The laboratory simulations were used to compare with current estimates based mainly on flow sheet estimates and spotty historical data. Three simulations of the bismuth phosphate precipitation process show that less that 1% of the Tc-99, Cs-135/137, Sr-90, I-129 carry down with the Pu product and thus these isotopes should have remained within the metals waste streams that after neutralization were sent to single shell tanks. Conversely, these isotopes should not be expected to be found in the first and subsequent cycle waste streams that went to cribs. Measurable quantities (~20 to 30%) of the lanthanides, yttrium, and trivalent actinides (Am and Cm) do precipitate with the Pu product, which is higher than the 10% estimate made for current inventory projections. Surprisingly, Se (added as selenate form) also shows about 10% association with the Pu/bismuth phosphate solids. We speculate that the incorporation of some Se into the bismuth phosphate precipitate is caused by selenate substitution into crystal lattice sites for the phosphate. The bulk of the U daughter product Th-234 and Np-237 daughter product Pa-233 also associate with the solids. We suspect that the Pa daughter products of U (Pa-234 and Pa-231) would also co-precipitate with the bismuth phosphate induced solids. No more than 1 % of the Sr-90 and Sb-125 should carry down with the Pu product that ultimately was purified. Thus the current scheme used to estimate where fission products end up being disposed overestimates by one order of magnitude the

  15. Cherenkov light detection as a velocity selector for uranium fission products at intermediate energies

    Science.gov (United States)

    Yamaguchi, T.; Enomoto, A.; Kouno, J.; Yamaki, S.; Matsunaga, S.; Suzaki, F.; Suzuki, T.; Abe, Y.; Nagae, D.; Okada, S.; Ozawa, A.; Saito, Y.; Sawahata, K.; Kitagawa, A.; Sato, S.

    2014-12-01

    The in-flight particle separation capability of intermediate-energy radioactive ion (RI) beams produced at a fragment separator can be improved with the Cherenkov light detection technique. The cone angle of Cherenkov light emission varies as a function of beam velocity. This can be exploited as a velocity selector for secondary beams. Using heavy ion beams available at the HIMAC synchrotron facility, the Cherenkov light angular distribution was measured for several thin radiators with high refractive indices (n = 1.9 ~ 2.1). A velocity resolution of ~10-3 was achieved for a 56Fe beam with an energy of 500 MeV/nucleon. Combined with the conventional rigidity selection technique coupled with energy-loss analysis, the present method will enable the efficient selection of an exotic species from huge amounts of various nuclides, such as uranium fission products at the BigRIPS fragment separator located at the RI Beam Factory.

  16. PADLOC: a one-dimensional computer program for calculating coolant and plateout fission product concentrations. [HTGR

    Energy Technology Data Exchange (ETDEWEB)

    Hudritsch, W.W.; Smith, P.D.

    1977-11-01

    The one-dimensional computer program PADLOC is designed to analyze steady-state and time-dependent plateout of fission products in an arbitrary network of pipes. The problem solved is one of mass transport of impurities in a fluid, including the effects of sources in the fluid and in the plateout surfaces, convection along the flow paths, decay, adsorption on surfaces (plateout), and desorption from surfaces. These phenomena are governed by a system of coupled, nonlinear partial differential equations. The solution is achieved by (a) linearizing the equations about an approximate solution, employing a Newton Raphson iteration technique, (b) employing a finite difference solution method with an implicit time integration, and (c) employing a substructuring technique to logically organize the systems of equations for an arbitrary flow network.

  17. Thermodynamics of fission products in dispersion fuel designs - first principles modeling of defect behavior in bulk and at interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiang-yand [Los Alamos National Laboratory; Uberuaga, Blas P [Los Alamos National Laboratory; Nerikar, Pankaj [Los Alamos National Laboratory; Sickafus, Kurt E [Los Alamos National Laboratory; Stanek, Chris R [Los Alamos National Laboratory

    2009-01-01

    Density functional theory (DFT) calculations of fission product (Xe, Sr, and Cs) incorporation and segregation in alkaline earth metal oxides, HfO{sub 2} and UO{sub 2} oxides, and the MgO/(U, Hf, Ce)O{sub 2} interfaces have been carried out. In the case of UO{sub 2}, the calculations were performed using spin polarization and with a Hubbard U term characterizing the on-sit Coulomb repulsion between the localized 5f electrons. The fission product solution energies in bulk UO{sub 2{+-}x} have been calculated as a function of non-stoichiometry x, and were compared to that in MgO. These calculations demonstrate that the fission product incorporation energies in MgO are higher than in HfO{sub 2}. However, this trend is reversed or reduced for alkaline earth oxides with larger cation sizes. The solution energies of fission products in MgO are substantially higher than in UO{sub 2{+-}x}, except for the case of Sr in the hypostoichiometric case. Due to size effects, the thermodynamic driving force of segregation for Xe and Cs from bulk MgO to the MgO/fluorite interface is strong. However, this driving force is relatively weak for Sr.

  18. Preliminary investigations on the use of uranium silicide targets for fission Mo-99 production

    Energy Technology Data Exchange (ETDEWEB)

    Cols, H.; Cristini, P.; Marques, R.

    1997-08-01

    The National Atomic Energy Commission (CNEA) of Argentine Republic owns and operates an installation for production of molybdenum-99 from fission products since 1985, and, since 1991, covers the whole national demand of this nuclide, carrying out a program of weekly productions, achieving an average activity of 13 terabecquerel per week. At present they are finishing an enlargement of the production plant that will allow an increase in the volume of production to about one hundred of terabecquerel. Irradiation targets are uranium/aluminium alloy with 90% enriched uranium with aluminium cladding. In view of international trends held at present for replacing high enrichment uranium (HEU) for enrichment values lower than 20 % (LEU), since 1990 the authors are in contact with the RERTR program, beginning with tests to adapt their separation process to new irradiation target conditions. Uranium silicide (U{sub 3}Si{sub 2}) was chosen as the testing material, because it has an uranium mass per volume unit, so that it allows to reduce enrichment to a value of 20%. CNEA has the technology for manufacturing miniplates of uranium silicide for their purposes. In this way, equivalent amounts of Molybdenum-99 could be obtained with no substantial changes in target parameters and irradiation conditions established for the current process with Al/U alloy. This paper shows results achieved on the use of this new target.

  19. Substrate preference of citrus naringenin rhamnosyltransferases and their application to flavonoid glycoside production in fission yeast.

    Science.gov (United States)

    Ohashi, Takao; Hasegawa, Yuka; Misaki, Ryo; Fujiyama, Kazuhito

    2016-01-01

    Flavonoids, which comprise a large family of secondary plant metabolites, have received increased attention in recent years due to their wide range of features beneficial to human health. One of the most abundant flavonoid skeletons in citrus species is the flavanone naringenin, which is accumulated as glycosides containing terminal rhamnose (Rha) after serial glycosylation steps. The linkage type of Rha residues is a determining factor in the bitterness of the citrus fruit. Such Rha residues are attached by either an α1,2- or an α1,6-rhamnosyltransferase (1,2RhaT or 1,6RhaT). Although the genes encoding these RhaTs from pummelo (Citrus maxima) and orange (Citrus sinensis) have been functionally characterized, the details of the biochemical characterization, including the substrate preference, remain elusive due to the lack of availability of the UDP-Rha required as substrate. In this study, an efficient UDP-Rha in vivo production system using the engineered fission yeast expressing Arabidopsis thaliana rhamnose synthase 2 (AtRHM2) gene was constructed. The in vitro RhaT assay using the constructed UDP-Rha revealed that recombinant RhaT proteins (Cm1,2RhaT; Cs1,6RhaT; or Cm1,6RhaT), which were heterologously produced in fission yeast, catalyzed the rhamnosyl transfer to naringenin-7-O-glucoside as an acceptor. The substrate preference analysis showed that Cm1,2RhaT had glycosyl transfer activity toward UDP-xylose as well as UDP-Rha. On the other hand, Cs1,6RhaT and Cm1,6RhaT showed rhamnosyltransfer activity toward quercetin-3-O-glucoside in addition to naringenin-7-O-glucoside, indicating weak specificity toward acceptor substrates. Finally, naringin and narirutin from naringenin-7-O-glucoside were produced using the engineered fission yeast expressing the AtRHM2 and the Cm1,2RhaT or the Cs1,6RhaT genes as a whole-cell-biocatalyst.

  20. Study of the production of neutron-rich isotope beams issuing from fissions induced by fast neutrons; Etude de la production de faisceaux riches en neutrons par fission induite par neutrons rapides

    Energy Technology Data Exchange (ETDEWEB)

    Lau, Ch

    2000-09-15

    This work is a contribution to the PARRNe project (production of radioactive neutron-rich isotopes). This project is based on the fission fragments coming from the fission of 238-uranium induced by fast neutrons. The fast neutron flux is produced by the collisions of deutons in a converter. Thick targets of uranium carbide and liquid uranium targets have been designed in order to allow a quick release of fission fragments. A device, able to trap on a cryogenic thimble rare gas released by the target, has allowed the production of radioactive nuclei whose half-life is about 1 second. This installation has been settled to different deuton accelerators in the framework of the European collaboration SPIRAL-2. A calibration experiment has proved the feasibility of fixing an ISOL-type isotope separator to a 15 MV tandem accelerator, this installation can provide 500 nA deutons beams whose energy is 26 MeV and be a valuable tool for studying fast-neutron induced fission. Zinc, krypton, rubidium, cadmium, iodine, xenon and cesium beams have been produced in this installation. The most intense beams reach 10000 nuclei by micro-coulomb for 26 MeV deutons. An extra gain of 2 magnitude orders can be obtained by using a more specific ion source and by increasing the thickness of the target. Another extra gain of 2 magnitude orders involves 100 MeV deutons.

  1. Superasymmetric fission at intermediate energy and production of neutron-rich nuclei with A

    NARCIS (Netherlands)

    Huhta, M; Dendooven, P; Honkanen, A; Jokinen, A; Lhersonneau, G; Oinonen, M; Penttila, H; Perajarvi, K; Rubchenya, VA; Aysto, J

    1997-01-01

    The yields of neutron-rich Ni, Cu, Zn, Ga and Ge-isotopes were measured in 25 MeV proton induced fission of U-238 using the ion guide-based isotope separator technique. The results indicate enhancement for superasymmetric mass division at intermediate excitation energy of the fissioning nucleus and

  2. Energy Dependence of Neutron-Induced Fission Product Yields of 235U, 238U and 239Pu Between 0.5 and 14.8 MeV

    Science.gov (United States)

    Gooden, Matthew; Tornow, Werner; Tonchev, Anton; Vieira, Dave; Wilhelmy, Jerry; Arnold, Charles; Fowler, Malcolm; Stoyer, Mark

    2014-09-01

    Under a joint collaboration between TUNL-LANL-LLNL, a set of absolute fission product yield measurements have been performed. The energy dependence of a number of cumulative fission products between 0.5 and 14.8 MeV have been measured using quasi-monoenergetic neutron beams for three actinide targets, 235U, 238U and 239Pu, between 0.5 and 14.8 MeV. The FPYs were measured by a combination of activation utilizing specially designed dual-fission chambers and γ-ray counting. The dual-fission chambers are back-to-back ionization chambers encasing a target with thin deposits of the same target isotope in each chamber. This method allows for the direct measurement of the fission rate in the activation target with no reference to the fission cross-section, reducing uncertainties. γ-ray counting was performed on well-shield HPGe detectors over a period of 2 months per activation to properly identify fission products. Reported are absolute cumulative fission product yields for incident neutron energies of 0.5, 1.37, 2.4, 4.6 and 14.8 MeV.

  3. Neutron-energy-dependent defect production cross sections for fission and fusion applications

    Energy Technology Data Exchange (ETDEWEB)

    Odette, G.R.; Doiron, D.R.

    1976-06-01

    Neutron cross sections for displacements and post-short-term cascade annealing defects are derived from nuclear kinematics calculations of primary atomic recoil energy distributions and the number of secondary defects produced per primary as a function of recoil energy. For the first time, recoil kinematics of charged- and multiple-particle emission reactions are treated rigorously using a compound-nucleus evaporation spectrum nuclear model. Secondary-defect production functions, derived from computer simulation experiments, are taken from the literature. Spectral-averaged defect production cross sections for a fusion reactor first-wall-type environment are on the order of 1.5 to 2.5 times those for a fast fission reactor core-type spectrum. The indicated range of uncertainty is primarily due to secondary-defect production model sensitivity. Nuclear model and data errors are expected to become more significant at high neutron energies, greater than approximately 20 MeV. Fusion reactor environments are found to produce some very energetic recoils and high-energy release events due to charged-particle reactions such as (n,..cap alpha..).

  4. Development of an evaluation method of fission product release fraction from High Temperature Gas-cooled Reactor fuel

    Energy Technology Data Exchange (ETDEWEB)

    Sawa, Kazuhiro; Minato, Kazuo; Fukuda, Kousaku [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1996-11-01

    The High Temperature Gas-cooled Reactor (HTGR) uses coated particles as fuel. Current coated particle is a microsphere of fuel kernel with TRISO coatings. The TRISO coatings consist of a low-density, porous pyrolytic carbon (PyC) buffer layer adjacent to the spherical fuel kernel, followed by an inner isotropic PyC layer, a SiC layer and a final (outer) PyC layer. An evaluation method of fission product release behavior during the normal operation was developed. Key issues of fission gas release model were: (1) fission gas releases from matrix contamination uranium and through-coatings failed particle were separately modeled and (2) burnup and fast neutron irradiation effects were newly considered. For metallic fission product, fractional release of cesium from coated fuel particles was investigated by comparing measured data in an irradiation test which contained three kinds of fuel particles; artificially bored particles simulating through-coatings failed particles, as-manufactured SiC-failed particles and intact particles. Through the comparison of measured and calculated fractional releases, an equivalent diffusion coefficient of SiC layer in the SiC-failed particle was introduced. This report describes the developed model together with validation result of the release model. (author)

  5. Determination of relative krypton fission product yields from 14 MeV neutron induced fission of 238U at the National Ignition Facility

    Science.gov (United States)

    Edwards, E. R.; Cassata, W. S.; Velsko, C. A.; Yeamans, C. B.; Shaughnessy, D. A.

    2016-11-01

    Precisely-known fission yield distributions are needed to determine a fissioning isotope and the incident neutron energy in nuclear security applications. 14 MeV neutrons from DT fusion at the National Ignition Facility induce fission in depleted uranium contained in the target assembly hohlraum. The fission yields of Kr isotopes (85m, 87, 88, and 89) are measured relative to the cumulative yield of 88Kr and compared to previously tabulated values. The results from this experiment and England and Rider are in agreement, except for the 85mKr/88Kr ratio, which may be the result of incorrect nuclear data.

  6. Comparison of fission product release predictions using PARFUME with results from the AGR-1 safety tests

    Energy Technology Data Exchange (ETDEWEB)

    Blaise Collin

    2014-09-01

    Safety tests were conducted on fourteen fuel compacts from AGR-1, the first irradiation experiment of the Advanced Gas Reactor (AGR) Fuel Development and Qualification program, at temperatures ranging from 1600 to 1800°C to determine fission product release at temperatures that bound reactor accident conditions. The PARFUME (PARticle FUel ModEl) code was used to predict the release of fission products silver, cesium, strontium, and krypton from fuel compacts containing tristructural isotropic (TRISO) coated particles during the safety tests, and the predicted values were compared with experimental results. Preliminary comparisons between PARFUME predictions and post-irradiation examination (PIE) results of the safety tests show different trends in the prediction of the fractional release depending on the species, and it leads to different conclusions regarding the diffusivities used in the modeling of fission product transport in TRISO-coated particles: • For silver, the diffusivity in silicon carbide (SiC) might be over-estimated by a factor of at least 102 to 103 at 1600°C and 1700°C, and at least 10 to 102 at 1800°C. The diffusivity of silver in uranium oxy-carbide (UCO) might also be over-estimated, but the available data are insufficient to allow definitive conclusions to be drawn. • For cesium, the diffusivity in UCO might be over-estimated by a factor of at least 102 to 103 at 1600°C, 105 at 1700°C, and 103 at 1800°C. The diffusivity of cesium in SiC might also over-estimated, by a factor of 10 at 1600°C and 103 at 1700°C, based upon the comparisons between calculated and measured release fractions from intact particles. There is no available estimate at 1800°C since all the compacts heated up at 1800°C contain particles with failed SiC layers whose release dominates the release from intact particles. • For strontium, the diffusivity in SiC might be over-estimated by a factor of 10 to 102 at 1600 and 1700°C, and 102 to 103 at 1800°C. These

  7. Nuclear Data Requirements for the Production of Medical Isotopes in Fission Reactors and Particle Accelerators

    CERN Document Server

    Garland, M A; Talbert, R J; Mashnik, S G; Wilson, W B

    1999-01-01

    Through decades of effort in nuclear data development and simulations of reactor neutronics and accelerator transmutation, a collection of reaction data is continuing to evolve with the potential of direct applications to the production of medical isotopes. At Los Alamos the CINDER'90 code and library have been developed for nuclide inventory calculations using neutron-reaction (En < 20 MeV) and/or decay data for 3400 nuclides; coupled with the LAHET Code System (LCS), irradiations in neutron and proton environments below a few GeV are tractable; additional work with the European Activation File, the HMS-ALICE code and the reaction models of MCNPX (CEM95, BERTINI, or ISABEL with or without preequilibrium, evaporation and fission) have been used to produce evaluated reaction data for neutrons and protons to 1.7 GeV. At the Pacific Northwest National Laboratory, efforts have focused on production of medical isotopes and the identification of available neutron reaction data from results of integral measuremen...

  8. Primary system fission product release and transport: A state-of-the-art report to the committee on the safety of nuclear installations

    Energy Technology Data Exchange (ETDEWEB)

    Wright, A.L. [Oak Ridge National Lab., TN (United States)

    1994-06-01

    This report presents a summary of the status of research activities associated with fission product behavior (release and transport) under severe accident conditions within the primary systems of water-moderated and water-cooled nuclear reactors. For each of the areas of fission product release and fission product transport, the report summarizes relevant information on important phenomena, major experiments performed, relevant computer models and codes, comparisons of computer code calculations with experimental results, and general conclusions on the overall state of the art. Finally, the report provides an assessment of the overall importance and knowledge of primary system release and transport phenomena and presents major conclusions on the state of the art.

  9. Determination of Fission Product Yields of 235U, 238U and 239Pu for Neutron Energies from 0.5 to 14.8 MeV

    Science.gov (United States)

    Gooden, Matthew; Arnold, Charles; Becker, John; Bhatia, Chitra; Bhike, Megha; Fowler, Malcolm; Howell, Calvin; Kelley, John; Stoyer, Mark; Tonchev, Anton; Tornow, Werner; Vieira, Dave; Wilhelmy, Jerry

    2014-03-01

    A joint TUNL-LANL-LLNL collaboration has been formed to study the issue of possible energy dependences for certain fission product isotopes. Work has been carried out at the TUNL 10 MV Tandem accelerator which produces nearly mono-energetic neutrons via either 2H(d,n)3He,3H(d,n)4He,or3H(p,n)3He reactions. Three dual fission ionization chambers dedicated to 235U, 238U and 239Pu thick target foils and thin monitor foils respectively, were exposed to the neutron beams. After irradiation, thick target foils were gamma counted over a period of 1-2 months and characteristic gamma rays from fission products were recorded using HPGe detectors at TUNL's low background counting area. Using the dual fission chambers, relative fission product yield were determined at a high precision of 2-3 % as well as absolute fission product yields at a lower precision of 5-6 %. Preliminary results will be presented for a number of fission product isotopes over the incident neutron energy range of 0.5 to 14.8 MeV.

  10. Study on collection efficiency of fission products by spray: Experimental device and modelling

    Energy Technology Data Exchange (ETDEWEB)

    Ducret, D.; Roblot, D.; Vendel, J. [Institut de Protection et de Surete Nucleaire, Gif-Sur-Yvette (France); Billarand, Y. [ECCO Pharmacie et Chimie, Neuilly (France)

    1997-08-01

    Consequences of an hypothetical overheating reactor accident in nuclear power plants can be limited by spraying cold water drops into containment building. The spray reduces the pressure and the temperature levels by condensation of steam and leads to the washout of fission products (aerosols and gaseous iodine). The present study includes a large program devoted to the evaluation of realistic washout rates. An experimental device (named CARAIDAS) was designed and built in order to determine the collection efficiency of aerosols and iodine absorption by drops with representative conditions of post-accident atmosphere. This experimental device is presented in the paper and more particularly: (1) the experimental enclosure in which representative thermodynamic conditions can be achieved, (2) the monosized drops generator, the drops diameter measurement and the drops collector, (3) the cesium iodide aerosols generator and the aerosols measurements. Modelling of steam condensation on drops aerosols collection and iodine absorption are described. First experimental and code results on drops and aerosols behaviour are compared. 8 refs., 18 figs.

  11. Hot beta particles in the lung: Results from dogs exposed to fission product radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, F.F.; Griffith, W.C.; Hobbs, C.H. [and others

    1995-12-01

    The Chernobyl nuclear reactor accident resulted in the release of uranium dioxide fuel and fission product radionuclides into the environment with the fallout of respirable, highly radioactive particles that have been termed {open_quotes}hot beta particles.{close_quotes} There is concern that these hot beta particles (containing an average of 150-20,000 Bq/particle), when inhaled and deposited in the lung, may present an extraordinary hazard for the induction of lung cancer. We reviewed data from a group of studies in dogs exposed to different quantities of beta-emitting radionuclides with varied physical half-lives to determine if those that inhaled hot beta particles were at unusual risk for lung cancer. This analysis indicates that the average dose to the lung is adequate to predict biologic effects of lung cancer for inhaled beta-emitting radionuclides in the range of 5-50 Gy to the lung and with particle activities in the range of 0.10-50 Bq/particle.

  12. Cherenkov light detection as a velocity selector for uranium fission products at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, T., E-mail: yamaguti@phy.saitama-u.ac.jp [Department of Physics, Saitama University, Saitama 338-8570 (Japan); Enomoto, A.; Kouno, J.; Yamaki, S.; Matsunaga, S.; Suzaki, F.; Suzuki, T. [Department of Physics, Saitama University, Saitama 338-8570 (Japan); Abe, Y.; Nagae, D.; Okada, S.; Ozawa, A.; Saito, Y.; Sawahata, K. [Institute of Physics, University of Tsukuba, Ibaraki 305-8571 (Japan); Kitagawa, A.; Sato, S. [National Institute of Radiological Sciences, Chiba 263-8555 (Japan)

    2014-12-01

    The in-flight particle separation capability of intermediate-energy radioactive ion (RI) beams produced at a fragment separator can be improved with the Cherenkov light detection technique. The cone angle of Cherenkov light emission varies as a function of beam velocity. This can be exploited as a velocity selector for secondary beams. Using heavy ion beams available at the HIMAC synchrotron facility, the Cherenkov light angular distribution was measured for several thin radiators with high refractive indices (n=1.9∼2.1). A velocity resolution of ∼10{sup −3} was achieved for a {sup 56}Fe beam with an energy of 500 MeV/nucleon. Combined with the conventional rigidity selection technique coupled with energy-loss analysis, the present method will enable the efficient selection of an exotic species from huge amounts of various nuclides, such as uranium fission products at the BigRIPS fragment separator located at the RI Beam Factory. - Highlights: • The cone angle of Cherenkov light can be used as a velocity selector of RI beams. • Proof-of-principle experiments are made using heavy ions at intermediate energies. • Results demonstrate successful separation of RI beams produced by fragmentation. • A velocity resolution of 10{sup −3} is achieved for thin high refractive radiators.

  13. Investigation on high temperature vapor pressure of UO 2 containing simulated fission-product elements

    Science.gov (United States)

    Yano, T.; Ohtsubo, A.; Ishii, T.

    1984-06-01

    During the hypothetical core disruptive accident (HCDA) of a fast breeder reactor (FBR), the temperature of the fuel would rise above 3000 K. The experimental data concerning the saturated fuel vapor pressure are necessary for the analysis of the HCDA. In this study, the UO 2 containing Cs, Ba, Ag, or Sn was used to simulate the irradiated fuel in the FBR. The saturated vapor pressure of pure UO 2 and UO 2 containing Cs, Ba, Ag, or Sn at 3000 to 5000 K was measured dynamically with a pulse laser and a torsion pendulum. The surface of a specimen on the pendulum was heated to eject vapor by the injection of a giant pulse ruby laser beam. The pressure of the ejected vapor was measured by both the maximum rotation angle of the pendulum and the duration of vapor ejection. The saturated vapor pressure was theoretically calculated by using the ejected vapor pressure. The surface temperature of the specimen was estimated from the irradiated energy density measured with a laser energy meter. The saturated vapor pressure of UO 2 at 3640 to 5880 K measured in this study was near the extrapolated value of Ackermann's low temperature data. The vapor pressure of UO 2 containing Cs, Ba, Ag or Sn was higher than that of UO 2. The saturated vapor pressure of UO 2 and a solid fission products system was calculated by using these experimental data.

  14. Evaporation release behavior of volatile fission products from liquid sodium pool to the inert cover gas

    Energy Technology Data Exchange (ETDEWEB)

    Nakagiri, T.; Miyahara, S. [Oarai Engineering Center, Power Reactor and Nuclear Fuel Development Corp., Oaraimachi, Ibaraki (Japan)

    1996-12-01

    In fuel failure of sodium cooled fast breeder reactors, released volatile fission products (VFPs) such as iodine and cesium from the fuel will be dissolved into the liquid sodium coolant and transferred to the cover vaporization. In the cover gas system of the reactor, natural convection occurs due to temperature differences between the sodium pool and the gas phase. The release rates of VFPs together with sodium vaporization are considered to be controlled by the convection. In this study, three analytical models are developed and examined to calculate the transient release rates using the equilibrium partition coefficients of VFPs. The calculated release rates are compared with experimental results for sodium and sodium iodide. The release rate of sodium is closest to the calculation by the heterogeneous nucleation theory. The release rate of sodium iodide obtained from the experiment is between the release rates calculated by the model based on heat-and-mass transfer analogy and the Hill`s theory. From this study, it is confirmed that the realistic release rate of sodium is able to be calculated by the model based on the heterogeneous nucleation theory. The conservative release rate of sodium iodide is able to be calculated by the model based on the Hill`s theory using the equilibrium partition coefficient of sodium iodide. (author) 7 figs., 1 tab., 3 refs.

  15. Fast-neutron interaction with the fission product {sup 103}Rh

    Energy Technology Data Exchange (ETDEWEB)

    Smith, A.B. [Argonne National Lab., IL (United States)]|[Arizona Univ., Tucson, AZ (United States); Guenther, P.T. [Argonne National Lab., IL (United States)

    1993-09-01

    Neutron total and differential elastic- and inelastic-scattering cross sections of {sup 103}Rh are measured from {approximately} 0.7 to 4.5 MeV (totals) and from {approximately} 1.5 to 10 MeV (scattering) with sufficient detail to define the energy-averaged behavior of the neutron processes. Neutrons corresponding to excitations of groups of levels at 334 {plus_minus} 13, 536 {plus_minus} 10, 648 {plus_minus} 25, 796 {plus_minus} 20, 864 {plus_minus} 22, 1120 {plus_minus} 22, 1279 {plus_minus} 60, 1481 {plus_minus} 27 and 1683 {plus_minus} 39 keV were observed. Additional groups at 1840 {plus_minus} 79 and 1991 {plus_minus} 71 key were tentatively identified. Assuming the target is a collective nucleus reasonably approximated by a simple one-phonon vibrator, spherical-optical, dispersive-optical, and coupled-channels models were developed from the data base with attention to the parameterization of the large inelastic-scattering cross sections. The physical properties of these models are compared with theoretical predictions and the systematics of similar model parameterizations in this mass region. In particular, it is shown that the inelastic-scattering cross section of the {sup 103}Rh fission product is large at the relatively low energies of applied interest.

  16. Separation of the rare-earth fission product poisons from spent nuclear fuel

    Science.gov (United States)

    Christian, Jerry D.; Sterbentz, James W.

    2016-08-30

    A method for the separation of the rare-earth fission product poisons comprising providing a spent nuclear fuel. The spent nuclear fuel comprises UO.sub.2 and rare-earth oxides, preferably Sm, Gd, Nd, Eu oxides, with other elements depending on the fuel composition. Preferably, the provided nuclear fuel is a powder, preferably formed by crushing the nuclear fuel or using one or more oxidation-reduction cycles. A compound comprising Th or Zr, preferably metal, is provided. The provided nuclear fuel is mixed with the Th or Zr, thereby creating a mixture. The mixture is then heated to a temperature sufficient to reduce the UO.sub.2 in the nuclear fuel, preferably to at least to 850.degree. C. for Th and up to 600.degree. C. for Zr. Rare-earth metals are then extracted to form the heated mixture thereby producing a treated nuclear fuel. The treated nuclear fuel comprises the provided nuclear fuel having a significant reduction in rare-earths.

  17. Simulated fission product-SiC interaction in Triso-coated LEU or MEU HTGR fuel particles

    Energy Technology Data Exchange (ETDEWEB)

    Pearson, R.L.; Lindemer, T.B.; Beahm, E.C.

    1980-11-01

    Proliferation issues relating to the use of highly enriched uranium (HEU) have led to an evaluation of the fission product-SiC interaction problems that might arise if low enriched uranium (LEU) or medium enriched uranium (MEU) were used as fissile fuel in HTGR systems. Simulated Triso-coated UO/sub 2/, UC/sub 2/, and UO/sub 2//UC/sub 2/ particles mixed with varying amounts of Mo, Ru, Rh, Pd, Ag, and Cd were prepared. These fission products were chosen because, after full burnup, their concentrations are higher in LEU and MEU fuels than in HEU fuel. After the particles were heat treated in the laboratory, their behavior was examined by use of metallography, scanning electron microscopy, and electron microprobe x-ray analysis.

  18. History and Actual State of Non-HEU Fission-Based Mo-99 Production with Low-Performance Research Reactors

    Directory of Open Access Journals (Sweden)

    S. Dittrich

    2013-01-01

    Full Text Available Fifty years ago, one of the worldwide first industrial production processes to produce fission-Mo-99 for medical use had been started at ZfK Rossendorf (now: HZDR, Germany. On the occasion of this anniversary, it is worth to mention that this original process (called LITEMOL now together with its target concept used at that time can still be applied. LITEMOL can be adapted very easily to various research reactors and applied at each site, which maybe still of interest for very small-scale producers. Besides this original process, two further and actually proven processes are suitable as well and recommended for small-scale LEU fission Mo-99 production also. They are known under the names KSA/KSS COMPACT and ROMOL LITE and will be described below.

  19. Next Generation Nuclear Plant Phenomena Identification and Ranking Tables (PIRTs) Volume 3: Fission-Product Transport and Dose PIRTs

    Energy Technology Data Exchange (ETDEWEB)

    Morris, Robert Noel [ORNL

    2008-03-01

    This Fission Product Transport (FPT) Phenomena Identification and Ranking Technique (PIRT) report briefly reviews the high-temperature gas-cooled reactor (HTGR) FPT mechanisms and then documents the step-by-step PIRT process for FPT. The panel examined three FPT modes of operation: (1) Normal operation which, for the purposes of the FPT PIRT, established the fission product circuit loading and distribution for the accident phase. (2) Anticipated transients which were of less importance to the panel because a break in the pressure circuit boundary is generally necessary for the release of fission products. The transients can change the fission product distribution within the circuit, however, because temperature changes, flow perturbations, and mechanical vibrations or shocks can result in fission product movement. (3) Postulated accidents drew the majority of the panel's time because a breach in the pressure boundary is necessary to release fission products to the confinement. The accidents of interest involved a vessel or pipe break, a safety valve opening with or without sticking, or leak of some kind. Two generic scenarios were selected as postulated accidents: (1) the pressurized loss-of-forced circulation (P-LOFC) accident, and (2) the depressurized loss-of-forced circulation (D-LOFC) accidents. FPT is not an accident driver; it is the result of an accident, and the PIRT was broken down into a two-part task. First, normal operation was seen as the initial starting point for the analysis. Fission products will be released by the fuel and distributed throughout the reactor circuit in some fashion. Second, a primary circuit breach can then lead to their release. It is the magnitude of the release into and out of the confinement that is of interest. Depending on the design of a confinement or containment, the impact of a pressure boundary breach can be minimized if a modest, but not excessively large, fission product attenuation factor can be introduced into

  20. A study on the fission product release behavior during DUPIC pellet fabrication and the characteristics of cesium trapping

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Ho; Shin, Jin Myeong; Park, Geun Il; Nam, Seung Hee; Park, Jang Jin; Lee, Jung Won; Yang, Myung Seung [Korea Atomic Energy Reserach Institute, Daejon (Korea, Republic of)

    2001-11-15

    During the OREOX and sintering process in DUPIC fuel fabrication, fission products would be released from the spent fuel material. Radioactivity measurement using gamma spectrometry technique was performed to identify the radionuclide species released from the spent fuel material at high temperatures up to 1700 deg. C. It was revealed that Cs-137 is the main fission product released from the spent fuel material, and about 99% of Cs-137 is released during sintering process. Therefore, the trapping characteristics of inactive cesium using the fly ash filter in off-gas stream at high temperature was investigated in terms of reaction temperature, carrier gas and gas velocity. The amount of trapped cesium by the fly ash filter was increased with increasing reaction temperature, whereas it was decreased with increasing gas velocity.

  1. ENDF/B-VII.1 Nuclear Data for Science and Technology: Cross Sections, Covariances, Fission Product Yields and Decay Data

    Energy Technology Data Exchange (ETDEWEB)

    G. Palmiotti

    2011-12-01

    The ENDF/B-VII.1 library is our latest recommended evaluated nuclear data file for use in nuclear science and technology applications, and incorporates advances made in the five years since the release of ENDF/B-VII.0. These advances focus on neutron cross sections, covariances, fission product yields and decay data, and represent work by the US Cross Section Evaluation Working Group (CSEWG) in nuclear data evaluation that utilizes developments in nuclear theory, modeling, simulation, and experiment. The principal advances in the new library are: (1) An increase in the breadth of neutron reaction cross section coverage, extending from 393 nuclides to 418 nuclides; (2) Covariance uncertainty data for 185 of the most important nuclides, as documented in companion papers in this edition; (3) R-matrix analyses of neutron reactions on light nuclei, including isotopes of He, Li, and Be; (4) Resonance parameter analyses at lower energies and statistical high energy reactions at higher energies for isotopes of F, Cl, K, Ti, V, Mn, Cr, Ni, Zr and W; (5) Modifications to thermal neutron reactions on fission products (isotopes of Mo, Tc, Rh, Ag, Cs, Nd, Sm, Eu) and neutron absorber materials (Cd, Gd); (6) Improved minor actinide evaluations for isotopes of U, Np, Pu, and Am (we are not making changes to the major actinides 235,238U and 239Pu at this point, except for delayed neutron data, and instead we intend to update them after a further period of research in experiment and theory), and our adoption of JENDL-4.0 evaluations for isotopes of Cm, Bk, Cf, Es, Fm, and some other minor actinides; (7) Fission energy release evaluations; (8) Fission product yield advances for fission-spectrum neutrons and 14 MeV neutrons incident on 239Pu; and (9) A new Decay Data sublibrary. Integral validation testing of the ENDF/B-VII.1 library is provided for a variety of quantities: For nuclear criticality, the VII.1 library maintains the generally-good performance seen for VII.0 for a wide

  2. Transmutation of nuclear waste. Status report RAS programme 1994: Recycling and transmutation of actinides and fission products

    Energy Technology Data Exchange (ETDEWEB)

    Cordfunke, E.H.P.; Gruppelaar, H.; Franken, W.M.P.

    1995-07-01

    This report describes the status and progress of the Dutch RAS programme on `Recycling and Transmutation of Actinides and Fission Products` over the year 1994, which is the first year of the second 4-year programme. This programme is outlined and a short progress report is given over 1994, including a listing of 23 reports and publications over the year 1994. Highlights of 1994 were: The completion of long-lived fission-product transmutation studies, the initiation of small-scale demonstration experiments in the HFR on Tc and I, the issue of reports on the potential of the ALMR (Advanced Liquid Metal Reactor) for transmutation adn the participation and international cooperation on irradiation experiments with actinides in inert matrices. The remaining chapters contain more extended contributions on recent developments and selected topics, under the headings: Benefits and risks of partitioning and transmutation, Perspective of chemical partitioning, Inert matrices, Evolutionary options (MOX), Perspective of heavy water reactors, Perspective of fast burners, Perspective of accelerator-based systems, Thorium cycle, Fission-product transmutation, End scenarios, and Executive summary and recommendations. (orig.).

  3. A generalized method for characterization of 235U and 239Pu content using short-lived fission product gamma spectroscopy

    Science.gov (United States)

    Knowles, Justin; Skutnik, Steven; Glasgow, David; Kapsimalis, Roger

    2016-10-01

    Rapid nondestructive assay methods for trace fissile material analysis are needed in both nuclear forensics and safeguards communities. To address these needs, research at the Oak Ridge National Laboratory High Flux Isotope Reactor Neutron Activation Analysis facility has developed a generalized nondestructive assay method to characterize materials containing fissile isotopes. This method relies on gamma-ray emissions from short-lived fission products and makes use of differences in fission product yields to identify fissile compositions of trace material samples. Although prior work has explored the use of short-lived fission product gamma-ray measurements, the proposed method is the first to provide a complete characterization of isotopic identification, mass ratios, and absolute mass determination. Successful single fissile isotope mass recoveries of less than 6% recovery bias have been conducted on standards of 235U and 239Pu as low as 12 ng in less than 10 minutes. Additionally, mixtures of fissile isotope standards containing 235U and 239Pu have been characterized as low as 198 ng of fissile mass with less than 7% recovery bias. The generalizability of this method is illustrated by evaluating different fissile isotopes, mixtures of fissile isotopes, and two different irradiation positions in the reactor. It is anticipated that this method will be expanded to characterize additional fissile nuclides, utilize various irradiation facilities, and account for increasingly complex sample matrices.

  4. A physical description of fission product behavior fuels for advanced power reactors.

    Energy Technology Data Exchange (ETDEWEB)

    Kaganas, G.; Rest, J.; Nuclear Engineering Division; Florida International Univ.

    2007-10-18

    The Global Nuclear Energy Partnership (GNEP) is considering a list of reactors and nuclear fuels as part of its chartered initiative. Because many of the candidate materials have not been explored experimentally under the conditions of interest, and in order to economize on program costs, analytical support in the form of combined first principle and mechanistic modeling is highly desirable. The present work is a compilation of mechanistic models developed in order to describe the fission product behavior of irradiated nuclear fuel. The mechanistic nature of the model development allows for the possibility of describing a range of nuclear fuels under varying operating conditions. Key sources include the FASTGRASS code with an application to UO{sub 2} power reactor fuel and the Dispersion Analysis Research Tool (DART ) with an application to uranium-silicide and uranium-molybdenum research reactor fuel. Described behavior mechanisms are divided into subdivisions treating fundamental materials processes under normal operation as well as the effect of transient heating conditions on these processes. Model topics discussed include intra- and intergranular gas-atom and bubble diffusion, bubble nucleation and growth, gas-atom re-solution, fuel swelling and ?scion gas release. In addition, the effect of an evolving microstructure on these processes (e.g., irradiation-induced recrystallization) is considered. The uranium-alloy fuel, U-xPu-Zr, is investigated and behavior mechanisms are proposed for swelling in the {alpha}-, intermediate- and {gamma}-uranium zones of this fuel. The work reviews the FASTGRASS kinetic/mechanistic description of volatile ?scion products and, separately, the basis for the DART calculation of bubble behavior in amorphous fuels. Development areas and applications for physical nuclear fuel models are identified.

  5. Fission product release and microstructure changes of irradiated MOX fuel at high temperatures

    Science.gov (United States)

    Colle, J.-Y.; Hiernaut, J.-P.; Wiss, T.; Beneš, O.; Thiele, H.; Papaioannou, D.; Rondinella, V. V.; Sasahara, A.; Sonoda, T.; Konings, R. J. M.

    2013-11-01

    burnups correspond reasonably well with measurement of Walker et al. [11]. All those data are shown Fig. 2.Fragments of 2-8 mg were chosen for the experiments. Since these specimens are small compared to the drilled sample size and were taken randomly, the precise radial position could not be determined, in particular the specimens of sample type, A and B could be from close radial locations.Specimens from each drilled sample type were annealed up to complete vaporisation (˜2600 K) at a speed of about 10 K min-1 in a Knudsen effusion mass spectrometer (KEMS) described previously [13,14]. In addition to helium and to the FGs all the species present in the vapour between 83 and 300 a.m.u. were measured during the heating. Additionally, the 85Kr isotope was analysed in a cold trap by β and γ counting. The long-lived fission gas isotopes correspond to masses 131, 132, 134 and 136 for Xe and 83, 84, 85 and 86 for Kr. The absolute quantities of gas released from specimens of sample types A and B were also determined using the in-house built Q-GAMES (Quantitative gas measurement system), described in detail in [15].For each of the samples, fragments were also annealed and measured in the KEMS up to specific temperatures corresponding to different stages of the FGs or He release. These fragments were subsequently analysed by Scanning Electron Microscopy (SEM, Philips XL40) [16] in order to investigate the relationship between structural changes, burn-up, irradiation temperature and fission products release. SEM observations were also done on the samples before the KEMS experiments and the fracture surface appearance of the samples is shown in Fig. 3, revealing the presence of the high burnup structure (HBS) in the Pu-rich agglomerates.A summary of the 12 samples analysed by KEMS, SEM and Q-GAMES is given in Table 1. At 1300 K no clear change potentially related to gas release appears in the UM and PA. At 1450 K a beginning of grain boundaries opening can be observed as well as

  6. HTR-2014 Paper Comparison of fission product release predictions using PARFUME with results from the AGR-1 irradiation experiment

    Energy Technology Data Exchange (ETDEWEB)

    Blaise Collin

    2001-10-01

    The PARFUME (PARticle FUel ModEl) code was used to predict fission product release from tristructural isotropic (TRISO) coated fuel particles and compacts during the first irradiation experiment (AGR-1) of the Advanced Gas Reactor Fuel Development and Qualification program. The PARFUME model for the AGR-1 experiment used the fuel compact volume average temperature for each of the 620 days of irradiation to calculate the release of fission products silver, cesium, and strontium from a representative particle for a select number of AGR-1 compacts. Post-irradiation examination (PIE) measurements provided data on release of fission products from fuel compacts and fuel particles, and retention of fission products in the compacts outside of the SiC layer. PARFUME-predicted fractional release of these fission products was determined and compared to the PIE measurements. Results show an overall over-prediction of the fractional release of cesium by PARFUME. For particles with failed silicon carbide (SiC) layers, the over-prediction is by a factor of about two, corresponding to an over-estimation of the diffusivity in uranium oxycarbide (UCO) by a factor of about 100. For intact particles, whose release is much lower, the over-prediction is by an average of about an order of magnitude, which could additionally be attributed to an over-estimated diffusivity in SiC by about 30%. The release of strontium from intact particles is also over-estimated by PARFUME, which also points towards an over-estimated diffusivity of strontium in either SiC or UCO, or possibly both. The measured strontium fractional release from intact particles varied considerably from compact to compact, making it difficult to assess the effective over-estimation of the diffusivities. Furthermore, the release of strontium from particles with failed SiC is difficult to observe experimentally due to the release from intact particles, preventing any conclusions to be made on the accuracy or validity of the

  7. Production Cycle for Large Scale Fission Mo-99 Separation by the Processing of Irradiated LEU Uranium Silicide Fuel Element Targets

    Directory of Open Access Journals (Sweden)

    Abdel-Hadi Ali Sameh

    2013-01-01

    Full Text Available Uranium silicide fuels proved over decades their exceptional qualification for the operation of higher flux material testing reactors with LEU elements. The application of such fuels as target materials, particularly for the large scale fission Mo-99 producers, offers an efficient and economical solution for the related facilities. The realization of such aim demands the introduction of a suitable dissolution process for the applied U3Si2 compound. Excellent results are achieved by the oxidizing dissolution of the fuel meat in hydrofluoric acid at room temperature. The resulting solution is directly behind added to an over stoichiometric amount of potassium hydroxide solution. Uranium and the bulk of fission products are precipitated together with the transuranium compounds. The filtrate contains the molybdenum and the soluble fission product species. It is further treated similar to the in-full scale proven process. The generated off gas stream is handled also as experienced before after passing through KOH washing solution. The generated alkaline fluoride containing waste solution is noncorrosive. Nevertheless fluoride can be selectively bonded as in soluble CaF2 by addition of a mixture of solid calcium hydroxide calcium carbonate to the sand cement mixture used for waste solidification. The generated elevated amounts of LEU remnants can be recycled and retargeted. The related technology permits the minimization of the generated fuel waste, saving environment, and improving processing economy.

  8. In-Plant Fission Product Behavior in SGTR Accident with Long-Term SBO

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Woon; Han, Seok Jung; Ahn, Kwang Il [KAERI, Daejeon (Korea, Republic of)

    2015-05-15

    The off-site AC power was recovered in 9 days after the accident in the NPS. Therefore safety injection by fire pump truck with fresh water or seawater is only available in the Fukushima accident. However, safety injection by fire pump truck is not always effective due to the high pressure of RPV inside or leakages of alternative water injection flow paths. In the SBO situations in pressurized water reactor plant (PWR), turbine driven auxiliary feedwater (TD-AFW) pump can inject water to the secondary side of steam generator. However, turbine inlet steam flow control valve cannot work properly when loss of vital DC power occurs. Vital DC power is designed to be maintained during 4 or 8 hours in the SBO conditions. In this paper motor-driven and turbine driven AFW pumps are all assumed to be not working at time 0 sec as a worst case assumption. Iodine pool-scrubbing can occur in the secondary side of the faulted steam generator. However, iodine pool-scrubbing in the secondary side of the faulted steam generator is assumed not to be working, due to the assumption of the loss of DC battery for turbine inlet flow control valve. Iodine pool-scrubbing is one of the long-term research issues in safety assessment of nuclear power plant severe accident. PHEBUS FPT series and THAI experiment projects are typical projects on the resolving source term issues in severe accident of nuclear power plants. However, iodine retention by pool scrubbing is still a debating issue. In such containment bypass sequences, fission products can be released out to environment directly from RCS without retention or deposition in containment structures. SGTR is one of the hazardous accident scenarios in the typical PSA, because SGTR induces a large release amount of source term to environment directly. A key operation strategy was the isolation of the broken reactor coolant system loop from the intact loop. Typical core degradation in SGTR scenarios occurs with multiple failures of the isolation

  9. Fission in a Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Younes, W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-10-26

    A three-year theory project was undertaken to study the fission process in extreme astrophysical environments, such as the crust of neutron stars. In the first part of the project, the effect of electron screening on the fission process was explored using a microscopic approach. For the first time, these calculations were carried out to the breaking point of the nucleus. In the second part of the project, the population of the fissioning nucleus was calculated within the same microscopic framework. These types of calculations are extremely computer-intensive and have seldom been applied to heavy deformed nuclei, such as fissioning actinides. The results, tools and methodologies produced in this work will be of interest to both the basic-science and nuclear-data communities.

  10. ASTEC V2 severe accident integral code: Fission product modelling and validation

    Energy Technology Data Exchange (ETDEWEB)

    Cantrel, L., E-mail: laurent.cantrel@irsn.fr; Cousin, F.; Bosland, L.; Chevalier-Jabet, K.; Marchetto, C.

    2014-06-01

    One main goal of the severe accident integral code ASTEC V2, jointly developed since almost more than 15 years by IRSN and GRS, is to simulate the overall behaviour of fission products (FP) in a damaged nuclear facility. ASTEC applications are source term determinations, level 2 Probabilistic Safety Assessment (PSA2) studies including the determination of uncertainties, accident management studies and physical analyses of FP experiments to improve the understanding of the phenomenology. ASTEC is a modular code and models of a part of the phenomenology are implemented in each module: the release of FPs and structural materials from degraded fuel in the ELSA module; the transport through the reactor coolant system approximated as a sequence of control volumes in the SOPHAEROS module; and the radiochemistry inside the containment nuclear building in the IODE module. Three other modules, CPA, ISODOP and DOSE, allow respectively computing the deposition rate of aerosols inside the containment, the activities of the isotopes as a function of time, and the gaseous dose rate which is needed to model radiochemistry in the gaseous phase. In ELSA, release models are semi-mechanistic and have been validated for a wide range of experimental data, and noticeably for VERCORS experiments. For SOPHAEROS, the models can be divided into two parts: vapour phase phenomena and aerosol phase phenomena. For IODE, iodine and ruthenium chemistry are modelled based on a semi-mechanistic approach, these FPs can form some volatile species and are particularly important in terms of potential radiological consequences. The models in these 3 modules are based on a wide experimental database, resulting for a large part from international programmes, and they are considered at the state of the art of the R and D knowledge. This paper illustrates some FPs modelling capabilities of ASTEC and computed values are compared to some experimental results, which are parts of the validation matrix.

  11. Chemical reactions of fission product deposits and iodine transport in primary circuit conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kalilainen, Jarmo, E-mail: jarmo.kalilainen@vtt.fi [VTT Technical Research Centre of Finland, P.O. Box 1000, BI7, FI02044 VTT Espoo (Finland); Kärkelä, Teemu; Zilliacus, Riitta; Tapper, Unto; Auvinen, Ari [VTT Technical Research Centre of Finland, P.O. Box 1000, BI7, FI02044 VTT Espoo (Finland); Jokiniemi, Jorma [VTT Technical Research Centre of Finland, P.O. Box 1000, BI7, FI02044 VTT Espoo (Finland); University of Eastern Finland, Department of Environmental Science, P.O. Box 1627, FI-70211 Kuopio (Finland)

    2014-02-15

    Highlights: • With CsI precursor, 20% of released iodine was in gaseous form in steam flow at 650 °C. • In similar conditions with Mo, gaseous iodine fraction was increased to 38–79%. • Boron trapped most of the caesium and iodine was almost completely released as gas. - Abstract: The objective of this work was to examine the chemical reactions taking place on primary circuit surfaces and their effect on fission product transport in a severe nuclear reactor accident. Especially transport of gaseous and aerosol phase iodine was studied. Caesium iodide (CsI) was used as precursor material for iodine species. Also, effects of molybdenum and boron on transport of iodine were investigated. The experimental work showed that when CsI alone was used as a precursor, as much as 20% of the released iodine was in gaseous form and the rest as aerosol particles. Aerosol particles were most likely CsI. When the amount of hydrogen in the carrier gas was increased, the fraction of gaseous iodine decreased. When Boron was added to the precursor, a glassy caesium borate surface was formed on the crucible. Boron trapped most of the caesium and also a fraction of iodine, causing almost all released iodine to be in gaseous form. When Mo was introduced in the precursor, most of the iodine was again released in gaseous form. Oxidised Mo reacted with caesium releasing iodine from CsI. The effect of Mo on iodine transport depended much on H{sub 2} concentration and was observed to be substantially greater on stainless steel surface. When stainless steel crucible was used, Mo was found in small amounts from aerosol particles, indicating that it was probably released as caesium molybdate or as molybdenum oxide.

  12. NEUTRON CROSS SECTION EVALUATIONS OF FISSION PRODUCTS BELOW THE FAST ENERGY REGION

    Energy Technology Data Exchange (ETDEWEB)

    OH,S.Y.; CHANG,J.; MUGHABGHAB,S.

    2000-05-11

    Neutron cross section evaluations of the fission-product isotopes, {sup 95}Mo, {sup 99}Tc, {sup 101}Ru, {sup 103}Rh, {sup 105}Pd, {sup 109}Ag, {sup 131}Xe, {sup 133}Cs, {sup 141}Pr, {sup 141}Nd, {sup 147}Sm, {sup 149}Sm, {sup 150}Sm, {sup 151}Sm, {sup 152}Sm, {sup 153}Eu, {sup 155}Gd, and {sup 157}Gd were carried out below the fast neutron energy region within the framework of the BNL-KAERI international collaboration. In the thermal energy region, the energy dependence of the various cross-sections was calculated by applying the multi-level Breit-Wigner formalism. In particular, the strong energy dependence of the coherent scattering lengths of {sup 155}Gd and {sup 157}Gd were determined and were compared with recent calculations of Lynn and Seeger. In the resonance region, the recommended resonance parameters, reported in the BNL compilation, were updated by considering resonance parameter information published in the literature since 1981. The s-wave and, if available, p-wave reduced neutron widths were analyzed in terms of the Porter-Thomas distribution to determine the average level spacings and the neutron strength functions. Average radiative widths were also calculated from measured values of resolved energy resonances. The average resonance parameters determined in this study were compared with those in the BNL and other compilations, as well as the ENDF/B-VI, JEF-2.2, and JENDL-3.2 data libraries. The unresolved capture cross sections of these isotopes, computed with the determined average resonance parameters, were compared with measurements, as well as the ENDF/B-VI evaluations. To achieve agreement with the measurements, in a few cases minor adjustments in the average resonance parameters were made. Because of astrophysical interest, the Maxwellian capture cross sections of these nuclides at a neutron temperature of 30 keV were computed and were compared with other compilations and evaluations.

  13. Parallel computation safety analysis irradiation targets fission product molybdenum in neutronic aspect using the successive over-relaxation algorithm

    Science.gov (United States)

    Susmikanti, Mike; Dewayatna, Winter; Sulistyo, Yos

    2014-09-01

    One of the research activities in support of commercial radioisotope production program is a safety research on target FPM (Fission Product Molybdenum) irradiation. FPM targets form a tube made of stainless steel which contains nuclear-grade high-enrichment uranium. The FPM irradiation tube is intended to obtain fission products. Fission materials such as Mo99 used widely the form of kits in the medical world. The neutronics problem is solved using first-order perturbation theory derived from the diffusion equation for four groups. In contrast, Mo isotopes have longer half-lives, about 3 days (66 hours), so the delivery of radioisotopes to consumer centers and storage is possible though still limited. The production of this isotope potentially gives significant economic value. The criticality and flux in multigroup diffusion model was calculated for various irradiation positions and uranium contents. This model involves complex computation, with large and sparse matrix system. Several parallel algorithms have been developed for the sparse and large matrix solution. In this paper, a successive over-relaxation (SOR) algorithm was implemented for the calculation of reactivity coefficients which can be done in parallel. Previous works performed reactivity calculations serially with Gauss-Seidel iteratives. The parallel method can be used to solve multigroup diffusion equation system and calculate the criticality and reactivity coefficients. In this research a computer code was developed to exploit parallel processing to perform reactivity calculations which were to be used in safety analysis. The parallel processing in the multicore computer system allows the calculation to be performed more quickly. This code was applied for the safety limits calculation of irradiated FPM targets containing highly enriched uranium. The results of calculations neutron show that for uranium contents of 1.7676 g and 6.1866 g (× 106 cm-1) in a tube, their delta reactivities are the still

  14. Neutron capture cross-section of fission products in the European activation file EAF-3. Presented at the NEA Specialists` Meeting on Fission Product Nuclear Data, JAERI, Japan, 25-27 May 1992

    Energy Technology Data Exchange (ETDEWEB)

    Kopecky, J.; Delfini, M.G.; Kamp, H.A.J. van der; Gruppelaar, H.; Nierop, D. [Netherlands Energy Research Foundation (ECN), Petten (Netherlands)

    1992-05-01

    This paper contains a description of the work performed to extend and revise the neutron capture data in the European Activation File (EAF-3) with emphasis on nuclides in the fission-product mass range. The starter was the EAF-1 data file from 1989. The present version, EAF/NG-3, contains (n,{gamma}) excitation functions for all nuclides (729 targets) with half-lives exceeding 1/2 day in the mass range from H-1 to Cm-248. The data file is equipped with a preliminary uncertainty file, that will be improved in the near future. (author). 19 refs.; 5 figs.; 3 tabs.

  15. Development of a fission product transport module predicting the behavior of radiological materials during sever accidents in a nuclear power plant

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Hyung Seok; Rhee, Bo Wook; Kim, Dong Ha [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-09-15

    Korea Atomic Energy Research Institute is developing a fission product transport module for predicting the behavior of radioactive materials in the primary cooling system of a nuclear power plant as a separate module, which will be connected to a severe accident analysis code, Core Meltdown Progression Accident Simulation Software (COMPASS). This fission product transport (COMPASS-FP) module consists of a fission product release model, an aerosol generation model, and an aerosol transport model. In the fission product release model there are three submodels based on empirical correlations, and they are used to simulate the fission product gases release from the reactor core. In the aerosol generation model, the mass conservation law and Raoult's law are applied to the mixture of vapors and droplets of the fission products in a specified control volume to find the generation of the aerosol droplet. In the aerosol transport model, empirical correlations available from the open literature are used to simulate the aerosol removal processes owing to the gravitational settling, inertia impaction, diffusiophoresis, and thermophoresis. The COMPASS-FP module was validated against Aerosol Behavior Code Validation and Evaluation (ABCOVE-5) test performed by Hanford Engineering Development Laboratory for comparing the prediction and test data. The comparison results assuming a non-spherical aerosol shape for the suspended aerosol mass concentration showed a good agreement with an error range of about ±6%. It was found that the COMPASS-FP module produced the reasonable results of the fission product gases release, the aerosol generation, and the gravitational settling in the aerosol removal processes for ABCOVE-5. However, more validation for other aerosol removal models needs to be performed.

  16. Decay Heat Analyses after Thermal-Neutron Fission of {sup 235}U and {sup 239}Pu by SCALE-6.1.3 with Recently Available Fission Product Yield Data

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Do Heon; Gil, Choong-Sup; Lee, Young-Ouk [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    The heat reaches about 1.5% after one hour and falls to 0.4% after a day. After a week it will be about 0.2%. The reactor, however, still requires further cooling for several years to keep the fuel rods safe. In general, the decay heat in the reactors can be calculated using a summation calculation method, which is simply the sum of the activities of the fission products produced during the fission process and after the reactor shutdown weighted by the mean decay energies. Consequently, the method is strongly dependent on the available nuclear structure data. Nowadays, the method has been implemented in various burnup and depletion programs such as ORIGEN and CINDER. In this study, the decay heat measurements after thermal-neutron fission of {sup 235}U and {sup 239}Pu have been evaluated by the ORIGEN-S with the decay data and fission product yield libraries included in the SCALE-6.1.3 software package. The new libraries were applied to the decay heat calculations, and the results were compared with those by the ORIGEN reference calculation. The decay heat measurements for very short cooling times after thermal-neutron fission of {sup 235}U and {sup 239}Pu have been evaluated by the ORIGEN-S summation calculation. The reference calculation results by the latest ORIGEN data libraries of the SCALE-6.1.3 have been validated with the measurements by ORNL and Studsvik. In addition, the generation of the new ORIGEN yield libraries has been completed based on the ENDF/B-VII.1, JEFF-3.1.1, JENDL/FPY-2011, and JENDL-4.0. The new libraries have been successfully applied to the decay heat calculations and comparative analyses have been devoted to verifying the importance of the fission product yield data when estimating the decay heat values for each isotope in a very short time. The decay data library occupies an important position in the ORIGEN summation calculation along with the fission product yield library.

  17. STEM-EDS analysis of fission products in neutron-irradiated TRISO fuel particles from AGR-1 experiment

    Science.gov (United States)

    Leng, B.; van Rooyen, I. J.; Wu, Y. Q.; Szlufarska, I.; Sridharan, K.

    2016-07-01

    Historic and recent post-irradiation-examination from the German AVR and Advanced Gas Reactor Fuel Development and Qualification Project have shown that 110 m Ag is released from intact tristructural isotropic (TRISO) fuel. Although TRISO fuel particle research has been performed over the last few decades, little is known about how metallic fission products are transported through the SiC layer, and it was not until March 2013 that Ag was first identified in the SiC layer of a neutron-irradiated TRISO fuel particle. The existence of Pd- and Ag-rich grain boundary precipitates, triple junction precipitates, and Pd nano-sized intragranular precipitates in neutron-irradiated TRISO particle coatings was investigated using Scanning Transmission Electron Microscopy and Energy Dispersive Spectroscopy analysis to obtain more information on the chemical composition of the fission product precipitates. A U-rich fission product honeycomb shape precipitate network was found near a micron-sized precipitate in a SiC grain about ∼5 μm from the SiC-inner pyrolytic carbon interlayer, indicating a possible intragranular transport path for uranium. A single Ag-Pd nano-sized precipitate was found inside a SiC grain, and this is the first research showing such finding in irradiated SiC. This finding may possibly suggest a possible Pd-assisted intragranular transport mechanism for Ag and may be related to void or dislocation networks inside SiC grains. Preliminary semi-quantitative analysis indicated the micron-sized precipitates to be Pd2Si2U with carbon existing inside these precipitates. However, the results of such analysis for nano-sized precipitates may be influenced by the SiC matrix. The results reported in this paper confirm the co-existence of Cd with Ag in triple points reported previously.

  18. Comparison of predicted and measured fission product behavior in the Fort St. Vrain HTGR during the first three cycles of operation

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, D.L.; Jovanovic, V.; Burnette, R.D.

    1985-10-01

    Fission product release from the reactor core has been predicted by the reference design methods and compared with reactor surveillance measurements and with the results of postirradiation examination (PIE) of spent FSV fuel elements. Overall, the predictive methods have been shown to be conservative: the predicted fission gas release at the end of Cycle 3 is about five times higher than observed. The dominant source of fission gas release is as-manufactured, heavy-metal contamination; in-service failure of the coated fuel particles appears to be negligible which is consistent with the PIE of spent fuel elements removed during the first two refuelings. The predicted releases of fission metals are insignificant compared to the release and subsequent decay of their gaseous precursors which is consistent with plateout probe measurements.

  19. Arrival time and magnitude of airborne fission products from the Fukushima, Japan, reactor incident as measured in Seattle, WA, USA

    CERN Document Server

    Leon, J Diaz; Knecht, A; Miller, M L; Robertson, R G H; Schubert, A G

    2011-01-01

    We report results of air monitoring started due to the recent natural catastrophe on March 11, 2011 in Japan and the severe ensuing damage to the Fukushima nuclear reactor complex. On March 17-18, 2011 we detected the first arrival of the airborne fission products 131-I, 132-I, 132-Te, 134-Cs, and 137-Cs in Seattle, WA, USA, by identifying their characteristic gamma rays using a germanium detector. The highest detected activity to date is <~32 mBq/m^3 of 131-I.

  20. Glass Ceramic Waste Forms for Combined CS+LN+TM Fission Products Waste Streams

    Energy Technology Data Exchange (ETDEWEB)

    Crum, Jarrod V.; Turo, Laura A.; Riley, Brian J.; Tang, Ming; Kossoy, Anna; Sickafus, Kurt E.

    2010-09-23

    In this study, glass ceramics were explored as an alternative waste form for glass, the current baseline, to be used for immobilizing alkaline/alkaline earth + lanthanide (CS+LN) or CS+LN+transition metal (TM) fission-product waste streams generated by a uranium extraction (UREX+) aqueous separations type process. Results from past work on a glass waste form for the combined CS+LN waste streams showed that as waste loading increased, large fractions of crystalline phases precipitated upon slow cooling.[1] The crystalline phases had no noticeable impact on the waste form performance by the 7-day product consistency test (PCT). These results point towards the development of a glass ceramic waste form for treating CS+LN or CS+LN+TM combined waste streams. Three main benefits for exploring glass ceramics are: (1) Glass ceramics offer increased solubility of troublesome components in crystalline phases as compared to glass, leading to increased waste loading; (2) The crystalline network formed in the glass ceramic results in higher heat tolerance than glass; and (3) These glass ceramics are designed to be processed by the same melter technology as the current baseline glass waste form. It will only require adding controlled canister cooling for crystallization into a glass ceramic waste form. Highly annealed waste form (essentially crack free) with up to 50X lower surface area than a typical High-Level Waste (HLW) glass canister. Lower surface area translates directly into increased durability. This was the first full year of exploring glass ceramics for the Option 1 and 2 combined waste stream options. This work has shown that dramatic increases in waste loading are achievable by designing a glass ceramic waste form as an alternative to glass. Table S1 shows the upper limits for heat, waste loading (based on solubility), and the decay time needed before treatment can occur for glass and glass ceramic waste forms. The improvements are significant for both combined waste

  1. Cement As a Waste Form for Nuclear Fission Products: The Case of (90)Sr and Its Daughters.

    Science.gov (United States)

    Dezerald, Lucile; Kohanoff, Jorge J; Correa, Alfredo A; Caro, Alfredo; Pellenq, Roland J-M; Ulm, Franz J; Saúl, Andrés

    2015-11-17

    One of the main challenges faced by the nuclear industry is the long-term confinement of nuclear waste. Because it is inexpensive and easy to manufacture, cement is the material of choice to store large volumes of radioactive materials, in particular the low-level medium-lived fission products. It is therefore of utmost importance to assess the chemical and structural stability of cement containing radioactive species. Here, we use ab initio calculations based on density functional theory (DFT) to study the effects of (90)Sr insertion and decay in C-S-H (calcium-silicate-hydrate) in order to test the ability of cement to trap and hold this radioactive fission product and to investigate the consequences of its β-decay on the cement paste structure. We show that (90)Sr is stable when it substitutes the Ca(2+) ions in C-S-H, and so is its daughter nucleus (90)Y after β-decay. Interestingly, (90)Zr, daughter of (90)Y and final product in the decay sequence, is found to be unstable compared to the bulk phase of the element at zero K but stable when compared to the solvated ion in water. Therefore, cement appears as a suitable waste form for (90)Sr storage.

  2. Comparison of various hours living fission products for absolute power density determination in VVER-1000 mock up in LR-0 reactor.

    Science.gov (United States)

    Košťál, Michal; Švadlenková, Marie; Koleška, Michal; Rypar, Vojtěch; Milčák, Ján

    2015-11-01

    Measuring power level of zero power reactor is a quite difficult task. Due to the absence of measurable cooling media heating, it is necessary to employ a different method. The gamma-ray spectroscopy of fission products induced within reactor operation is one of possible ways of power determination. The method is based on the proportionality between fission product buildup and released power. The (92)Sr fission product was previously preferred as nuclide for LR-0 power determination for short-time irradiation experiments. This work aims to find more appropriate candidates, because the (92)Sr, however suitable, has a short half-life, which limits the maximal measurable amount of fuel pins within a single irradiation batch. The comparison of various isotopes is realized for (92)Sr, (97)Zr, (135)I, (91)Sr, and (88)Kr. The comparison between calculated and experimentally determined (C/E-1 values) net peak areas is assessed for these fission products. Experimental results show that studied fission products, except (88)Kr, are in comparable agreement with (92)Sr results. Since (91)Sr has notably higher half-life than (92)Sr, (91)Sr seems to be more appropriate marker in experiments with a large number of measured fuel pins.

  3. ENDF/B-VII.1 Nuclear Data for Science and Technology: Cross Sections, Covariances, Fission Product Yields and Decay Data

    Science.gov (United States)

    Chadwick, M. B.; Herman, M.; Obložinský, P.; Dunn, M. E.; Danon, Y.; Kahler, A. C.; Smith, D. L.; Pritychenko, B.; Arbanas, G.; Arcilla, R.; Brewer, R.; Brown, D. A.; Capote, R.; Carlson, A. D.; Cho, Y. S.; Derrien, H.; Guber, K.; Hale, G. M.; Hoblit, S.; Holloway, S.; Johnson, T. D.; Kawano, T.; Kiedrowski, B. C.; Kim, H.; Kunieda, S.; Larson, N. M.; Leal, L.; Lestone, J. P.; Little, R. C.; McCutchan, E. A.; MacFarlane, R. E.; MacInnes, M.; Mattoon, C. M.; McKnight, R. D.; Mughabghab, S. F.; Nobre, G. P. A.; Palmiotti, G.; Palumbo, A.; Pigni, M. T.; Pronyaev, V. G.; Sayer, R. O.; Sonzogni, A. A.; Summers, N. C.; Talou, P.; Thompson, I. J.; Trkov, A.; Vogt, R. L.; van der Marck, S. C.; Wallner, A.; White, M. C.; Wiarda, D.; Young, P. G.

    2011-12-01

    The ENDF/B-VII.1 library is our latest recommended evaluated nuclear data file for use in nuclear science and technology applications, and incorporates advances made in the five years since the release of ENDF/B-VII.0. These advances focus on neutron cross sections, covariances, fission product yields and decay data, and represent work by the US Cross Section Evaluation Working Group (CSEWG) in nuclear data evaluation that utilizes developments in nuclear theory, modeling, simulation, and experiment. The principal advances in the new library are: (1) An increase in the breadth of neutron reaction cross section coverage, extending from 393 nuclides to 423 nuclides; (2) Covariance uncertainty data for 190 of the most important nuclides, as documented in companion papers in this edition; (3) R-matrix analyses of neutron reactions on light nuclei, including isotopes of He, Li, and Be; (4) Resonance parameter analyses at lower energies and statistical high energy reactions for isotopes of Cl, K, Ti, V, Mn, Cr, Ni, Zr and W; (5) Modifications to thermal neutron reactions on fission products (isotopes of Mo, Tc, Rh, Ag, Cs, Nd, Sm, Eu) and neutron absorber materials (Cd, Gd); (6) Improved minor actinide evaluations for isotopes of U, Np, Pu, and Am (we are not making changes to the major actinides 235,238U and 239Pu at this point, except for delayed neutron data and covariances, and instead we intend to update them after a further period of research in experiment and theory), and our adoption of JENDL-4.0 evaluations for isotopes of Cm, Bk, Cf, Es, Fm, and some other minor actinides; (7) Fission energy release evaluations; (8) Fission product yield advances for fission-spectrum neutrons and 14 MeV neutrons incident on 239Pu; and (9) A new decay data sublibrary. Integral validation testing of the ENDF/B-VII.1 library is provided for a variety of quantities: For nuclear criticality, the VII.1 library maintains the generally-good performance seen for VII.0 for a wide range

  4. ENDF/B-VII.1 Nuclear Data for Science and Technology: Cross Sections, Covariances, Fission Product Yields and Decay Data

    Energy Technology Data Exchange (ETDEWEB)

    Chadwick, M.B.; Herman, M.; Author(s): Chadwick,M.B.; Herman,M.; Oblozinsky,P.; Dunn,M.E.; Danon,Y.; Kahler,A.C.; Smith,D.L.; Pritychenko,B.; Arbanas,G.; Arcilla,R.; Brewer,R.; Brown,D.A.; Capote,R.; Carlson,A.D.; Cho,Y.S.; Derrien,H.; Guber,K.; Hale,G.M.; Hoblit,S.; Holloway,S.: Johnson,T.D.; Kawano,T.; Kiedrowski,B.C.; Kim,H.; Kunieda,S.; Larson,N.M.; Leal,L.; Lestone,J.P.; Little,R.C.; McCutchan,E.A.; MacFarlane,R.E.; MacInnes,M.; Mattoon,C.M.; McKnight,R.D.; Mughabghab,S.F.; Nobre,G.P.A.; Palmiotti,G.; Palumbo,A.; Pigni,M.T.; Pronyaev,V.G.; Sayer,R.O.; Sonzogni,A.A.; Summers,N.C.; Talou,P.; Thompson,I.J.; Trkov,A.; Vogt,R.L.; van der Marck,S.C.; Wallner,A.; White,M.C.; Wiarda,D.; Young,P.G.

    2011-12-01

    The ENDF/B-VII.1 library is our latest recommended evaluated nuclear data file for use in nuclear science and technology applications, and incorporates advances made in the five years since the release of ENDF/B-VII.0. These advances focus on neutron cross sections, covariances, fission product yields and decay data, and represent work by the US Cross Section Evaluation Working Group (CSEWG) in nuclear data evaluation that utilizes developments in nuclear theory, modeling, simulation, and experiment. The principal advances in the new library are: (1) An increase in the breadth of neutron reaction cross section coverage, extending from 393 nuclides to 423 nuclides; (2) Covariance uncertainty data for 190 of the most important nuclides, as documented in companion papers in this edition; (3) R-matrix analyses of neutron reactions on light nuclei, including isotopes of He, Li, and Be; (4) Resonance parameter analyses at lower energies and statistical high energy reactions for isotopes of Cl, K, Ti, V, Mn, Cr, Ni, Zr and W; (5) Modifications to thermal neutron reactions on fission products (isotopes of Mo, Tc, Rh, Ag, Cs, Nd, Sm, Eu) and neutron absorber materials (Cd, Gd); (6) Improved minor actinide evaluations for isotopes of U, Np, Pu, and Am (we are not making changes to the major actinides {sup 235,238}U and {sup 239}Pu at this point, except for delayed neutron data and covariances, and instead we intend to update them after a further period of research in experiment and theory), and our adoption of JENDL-4.0 evaluations for isotopes of Cm, Bk, Cf, Es, Fm, and some other minor actinides; (7) Fission energy release evaluations; (8) Fission product yield advances for fission-spectrum neutrons and 14 MeV neutrons incident on {sup 239}Pu; and (9) A new decay data sublibrary. Integral validation testing of the ENDF/B-VII.1 library is provided for a variety of quantities: For nuclear criticality, the VII.1 library maintains the generally-good performance seen for VII.0

  5. ENDF/B-VII.1 Nuclear Data for Science and Technology: Cross Sections, Covariances, Fission Product Yields and Decay Data

    Energy Technology Data Exchange (ETDEWEB)

    Chadwick, M. B. [Los Alamos National Laboratory (LANL); Herman, Micheal W [Brookhaven National Laboratory (BNL); Oblozinsky, Pavel [Brookhaven National Laboratory (BNL); Dunn, Michael E [ORNL; Danon, Y. [Rensselaer Polytechnic Institute (RPI); Kahler, A. [Los Alamos National Laboratory (LANL); Smith, Donald L. [Argonne National Laboratory (ANL); Pritychenko, B [Brookhaven National Laboratory (BNL); Arbanas, Goran [ORNL; Arcilla, r [Brookhaven National Laboratory (BNL); Brewer, R [Los Alamos National Laboratory (LANL); Brown, D A [Brookhaven National Laboratory (BNL); Capote, R. [International Atomic Energy Agency (IAEA); Carlson, A. D. [National Institute of Standards and Technology (NIST); Cho, Y S [Korea Atomic Energy Research Institute; Derrien, Herve [ORNL; Guber, Klaus H [ORNL; Hale, G. M. [Los Alamos National Laboratory (LANL); Hoblit, S [Brookhaven National Laboratory (BNL); Holloway, Shannon T. [Los Alamos National Laboratory (LANL); Johnson, T D [Brookhaven National Laboratory (BNL); Kawano, T. [Los Alamos National Laboratory (LANL); Kiedrowski, B C [Los Alamos National Laboratory (LANL); Kim, H [Korea Atomic Energy Research Institute; Kunieda, S [Los Alamos National Laboratory (LANL); Larson, Nancy M [ORNL; Leal, Luiz C [ORNL; Lestone, J P [Los Alamos National Laboratory (LANL); Little, R C [Los Alamos National Laboratory (LANL); Mccutchan, E A [Brookhaven National Laboratory (BNL); Macfarlane, R E [Los Alamos National Laboratory (LANL); MacInnes, M [Los Alamos National Laboratory (LANL); Matton, C M [Lawrence Livermore National Laboratory (LLNL); Mcknight, R D [Argonne National Laboratory (ANL); Mughabghab, S F [Brookhaven National Laboratory (BNL); Nobre, G P [Brookhaven National Laboratory (BNL); Palmiotti, G [Idaho National Laboratory (INL); Palumbo, A [Brookhaven National Laboratory (BNL); Pigni, Marco T [ORNL; Pronyaev, V. G. [Institute of Physics and Power Engineering (IPPE), Obninsk, Russia; Sayer, Royce O [ORNL; Sonzogni, A A [Brookhaven National Laboratory (BNL); Summers, N C [Lawrence Livermore National Laboratory (LLNL); Talou, P [Los Alamos National Laboratory (LANL); Thompson, I J [Lawrence Livermore National Laboratory (LLNL); Trkov, A. [Jozef Stefan Institute, Slovenia; Vogt, R L [Lawrence Livermore National Laboratory (LLNL); Van der Marck, S S [Nucl Res & Consultancy Grp, Petten, Netherlands; Wallner, A [University of Vienna, Austria; White, M C [Los Alamos National Laboratory (LANL); Wiarda, Dorothea [ORNL; Young, P C [Los Alamos National Laboratory (LANL)

    2011-01-01

    The ENDF/B-VII.1 library is our latest recommended evaluated nuclear data file for use in nuclear science and technology applications, and incorporates advances made in the five years since the release of ENDF/B-VII.0. These advances focus on neutron cross sections, covariances, fission product yields and decay data, and represent work by the US Cross Section Evaluation Working Group (CSEWG) in nuclear data evaluation that utilizes developments in nuclear theory, modeling, simulation, and experiment. The principal advances in the new library are: (1) An increase in the breadth of neutron reaction cross section coverage, extending from 393 nuclides to 423 nuclides; (2) Covariance uncertainty data for 190 of the most important nuclides, as documented in companion papers in this edition; (3) R-matrix analyses of neutron reactions on light nuclei, including isotopes of He; Li, and Be; (4) Resonance parameter analyses at lower energies and statistical high energy reactions for isotopes of Cl; K; Ti, V, Mn, Cr, Ni, Zr and W; (5) Modifications to thermal neutron reactions on fission products (isotopes of Mo, Tc, Rh, Ag, Cs, Nd, Sm, Eu) and neutron absorber materials (Cd, Gd); (6) Improved minor actinide evaluations for isotopes of U, Np, Pu, and Am (we are not making changes to the major actinides (235,238)U and (239)Pu at this point, except for delayed neutron data and covariances, and instead we intend to update them after a further period of research in experiment and theory), and our adoption of JENDL-4.0 evaluations for isotopes of Cm, Bk, Cf, Es; Fm; and some other minor actinides; (7) Fission energy release evaluations; (8) Fission product yield advances for fission-spectrum neutrons and 14 MeV neutrons incident on (239)Pu; and (9) A new decay data sublibrary. Integral validation testing of the ENDF/B-VII.1 library is provided for a variety of quantities: For nuclear criticality, the VII.1 library maintains the generally-good performance seen for VII.0 for a wide

  6. Summary Report: Glass-Ceramic Waste Forms for Combined Fission Products

    Energy Technology Data Exchange (ETDEWEB)

    Crum, Jarrod V.; Riley, Brian J.; Turo, Laura A.; Tang, Ming; Kossoy, Anna

    2011-09-23

    Glass-ceramic waste form development began in FY 2010 examining two combined waste stream options: (1) alkaline earth (CS) + lanthanide (Ln), and (2) + transition metal (TM) fission-product waste streams generated by the uranium extraction (UREX+) separations process. Glass-ceramics were successfully developed for both options however; Option 2 was selected over Option 1, at the conclusion of 2010, because Option 2 immobilized all three waste streams with only a minimal decrease in waste loading. During the first year, a series of three glass (Option 2) were fabricated that varied waste loading-WL (42, 45, and 50 mass%) at fixed molar ratios of CaO/MoO{sub 3} and B{sub 2}O{sub 3}/alkali both at 1.75. These glass-ceramics were slow cooled and characterized in terms of phase assemblage and preliminary irradiation stability. This fiscal year, further characterization was performed on the FY 2010 Option 2 glass-ceramics in terms of: static leach testing, phase analysis by transmission electron microscopy (TEM), and irradiation stability (electron and ion). Also, a new series of glass-ceramics were developed for Option 2 that varied the additives: Al{sub 2}O{sub 3} (0-6 mass%), molar ratio of CaO/MoO{sub 3} and B{sub 2}O{sub 3}/alkali (1.75 to 2.25) and waste loading (50, 55, and 60 mass%). Lastly, phase pure powellite and oxyapatite were synthesized for irradiation studies. Results of this fiscal year studies showed compositional flexibility, chemical stability, and radiation stability in the current glass-ceramic system. First, the phase assemblages and microstructure of all of the FY 2010 and 2011 glass-ceramics are very similar once subjected to the slow cool heat treatment. The phases identified in these glass-ceramics were oxyapatite, powellite, cerianite, and ln-borosilicate. This shows that variations in waste loading or additives can be accommodated without drastically changing the phase assemblage of the waste form, thus making the processing and performance

  7. Thermochemical prediction of chemical form distributions of fission products in LWR oxide fuels irradiated to high burnup

    Energy Technology Data Exchange (ETDEWEB)

    Moriyama, Kouki; Furuya, Hirotaka [Kyushu Univ., Fukuoka (Japan). Faculty of Engineering

    1997-09-01

    Based on the result of micro-gamma scanning of a fuel pin irradiated to high burnup in a commercial PWR, the radial distribution of chemical forms of fission products (FPs) in LWR fuel pins was theoretically predicted by a thermochemical computer code SOLGASMIX-PV. The absolute amounts of fission products generated in the fuel was calculated by ORIGEN-2 code, and the radial distributions of temperature and oxygen potential were calculated by taking the neutron depression and oxygen redistribution in the fuel into account. A fuel pellet was radially divided into 51 sections and chemical forms of FPs were calculated in each section. In addition, the effects of linear heat rating (LHR) and average O/U ratio on radial distribution of chemical form were evaluated. It was found that approximately 13 mole% of the total amount of Cs compounds exists as CsI and virtually remaining fraction as Cs{sub 2}MoO{sub 4} under the operation condition of LHR below 400 W/cm. On the other hand, when LHR is beyond 400 W/cm under the transient operation condition, its distribution did not change so much from the one under normal operation condition. (author)

  8. Fission yield measurements at IGISOL

    Directory of Open Access Journals (Sweden)

    Lantz M.

    2016-01-01

    Full Text Available The fission product yields are an important characteristic of the fission process. In fundamental physics, knowledge of the yield distributions is needed to better understand the fission process. For nuclear energy applications good knowledge of neutroninduced fission-product yields is important for the safe and efficient operation of nuclear power plants. With the Ion Guide Isotope Separator On-Line (IGISOL technique, products of nuclear reactions are stopped in a buffer gas and then extracted and separated by mass. Thanks to the high resolving power of the JYFLTRAP Penning trap, at University of Jyväskylä, fission products can be isobarically separated, making it possible to measure relative independent fission yields. In some cases it is even possible to resolve isomeric states from the ground state, permitting measurements of isomeric yield ratios. So far the reactions U(p,f and Th(p,f have been studied using the IGISOL-JYFLTRAP facility. Recently, a neutron converter target has been developed utilizing the Be(p,xn reaction. We here present the IGISOL-technique for fission yield measurements and some of the results from the measurements on proton induced fission. We also present the development of the neutron converter target, the characterization of the neutron field and the first tests with neutron-induced fission.

  9. Exact Solution of Fractional Diffusion Model with Source Term used in Study of Concentration of Fission Product in Uranium Dioxide Particle*

    Institute of Scientific and Technical Information of China (English)

    FANG Chao; CAO Jian-Zhu; SUN Li-Feng

    2011-01-01

    The exact solution of fractional diffusion model with a location-independent source term used in the study of the concentration of fission product in spherical uranium dioxide (U02) particle is built. The adsorption effect of the fission product on the surface of the U02 particle and the delayed decay effect are also considered. The solution is given in terms of Mittag-Leffler function with finite Hankel integral transformation and Laplace transformation. At last, the reduced forms of the solution under some special physical conditions, which is used in nuclear engineering, are obtained and corresponding remarks are given to provide significant exact results to the concentration analysis of nuclear fission products in nuclear reactor.

  10. Measurements of extinct fission products in nuclear bomb debris: Determination of the yield of the Trinity nuclear test 70 y later.

    Science.gov (United States)

    Hanson, Susan K; Pollington, Anthony D; Waidmann, Christopher R; Kinman, William S; Wende, Allison M; Miller, Jeffrey L; Berger, Jennifer A; Oldham, Warren J; Selby, Hugh D

    2016-07-19

    This paper describes an approach to measuring extinct fission products that would allow for the characterization of a nuclear test at any time. The isotopic composition of molybdenum in five samples of glassy debris from the 1945 Trinity nuclear test has been measured. Nonnatural molybdenum isotopic compositions were observed, reflecting an input from the decay of the short-lived fission products (95)Zr and (97)Zr. By measuring both the perturbation of the (95)Mo/(96)Mo and (97)Mo/(96)Mo isotopic ratios and the total amount of molybdenum in the Trinity nuclear debris samples, it is possible to calculate the original concentrations of the (95)Zr and (97)Zr isotopes formed in the nuclear detonation. Together with a determination of the amount of plutonium in the debris, these measurements of extinct fission products allow for new estimates of the efficiency and yield of the historic Trinity test.

  11. Production of Fission Product 99Mo using High-Enriched Uranium Plates in Polish Nuclear Research Reactor MARIA: Technology and Neutronic Analysis

    Directory of Open Access Journals (Sweden)

    Jaroszewicz Janusz

    2014-07-01

    Full Text Available The main objective of 235U irradiation is to obtain the 99mTc isotope, which is widely used in the domain of medical diagnostics. The decisive factor determining its availability, despite its short lifetime, is a reaction of radioactive decay of 99Mo into 99mTc. One of the possible sources of molybdenum can be achieved in course of the 235U fission reaction. The paper presents activities and the calculation results obtained upon the feasibility study on irradiation of 235U targets for production of 99Mo in the MARIA research reactor. Neutronic calculations and analyses were performed to estimate the fission products activity for uranium plates irradiated in the reactor. Results of dummy targets irradiation as well as irradiation uranium plates have been presented. The new technology obtaining 99Mo is based on irradiation of high-enriched uranium plates in standard reactor fuel channel and calculation of the current fission power generation. Measurements of temperatures and the coolant flow in the molybdenum installation carried out in reactor SAREMA system give online information about the current fission power generated in uranium targets. The corrective factors were taken into account as the heat generation from gamma radiation from neighbouring fuel elements as well as heat exchange between channels and the reactor pool. The factors were determined by calibration measurements conducted with aluminium mock-up of uranium plates. Calculations of fuel channel by means of REBUS code with fine mesh structure and libraries calculated by means of WIMS-ANL code were performed.

  12. Assessment of pheromone production and response in fission yeast by a halo test of induced sporulation

    DEFF Research Database (Denmark)

    Egel, R; Willer, M; Kjaerulff, S

    1994-01-01

    We describe a rapid, sensitive and semi-quantitative plate assay for monitoring pheromone activity in the fission yeast Schizosaccharomyces pombe. It is based on the observation that meiosis requires stimulation by pheromone and exploits diploid strains that will only sporulate after addition...... of exogenous pheromone. The tester strains are heterozygous for mating type, are non-switching, and are mutated in one of the early subfunctions (either mat1-Mc or mat1-Pc), so that meiosis is only induced after exposure to exogenous pheromone (M-factor or P-factor, respectively). Pheromone activity...

  13. Observation of new microsecond isomers among fission products of 345 MeV/nucleon 238U

    CERN Document Server

    Kameda, D; Ohnishi, T; Kusaka, K; Yoshida, A; Yoshida, K; Ohtake, M; Fukuda, N; Takeda, H; Tanaka, K; Inabe, N; Yanagisawa, Y; Gono, Y; Watanabe, H; Otsu, H; Baba, H; Ichihara, T; Yamaguchi, Y; Takechi, M; Nishimura, S; Ueno, H; Yoshimi, A; Sakurai, H; Motobayashi, T; Nakao, T; Mizoi, Y; Matsushita, M; Ieki, K; Kobayashi, N; Tanaka, K; Kawada, Y; Tanaka, N; Deguchi, S; Satou, Y; Kondo, Y; Nakamura, T; Yoshinaga, K; Ishii, C; Yoshii, H; Miyashita, Y; Uematsu, N; Shiraki, Y; Sumikama, T; Chiba, J; Ideguchi, E; Saito, A; Yamaguchi, T; Hachiuma, I; Suzuki, T; Moriguchi, T; Ozawa, A; Ohtsubo, T; Famiano, M A; Geissel, H; Nettleton, A S; Tarasov, O B; Bazin, D; Sherrill, B M; Manikonda, S L; Nolen, J A

    2012-01-01

    A search for isomeric gamma-decays among fission fragments from 345 MeV/nucleon 238U has been performed at the RIKEN Nishina Center RI Beam Factory. Fission fragments were selected and identified using the superconducting in-flight separator BigRIPS and were implanted in an aluminum stopper. Delayed gamma-rays were detected using three clover-type high-purity germanium detectors located at the focal plane within a time window of 20 microseconds following the implantation. We identified a total of 54 microsecond isomers with half-lives of ~0.1 - 10 microseconds, including discovery of 18 new isomers in very neutron-rich nuclei: 59Tim, 90Asm, 92Sem, 93Sem, 94Brm, 95Brm, 96Brm, 97Rbm, 108Nbm, 109Mom, 117Rum, 119Rum, 120Rhm, 122Rhm, 121Pdm, 124Pdm, 124Agm and 126Agm, and obtained a wealth of spectroscopic information such as half-lives, gamma-ray energies, gamma-ray relative intensities and gamma-gamma coincidences over a wide range of neutron-rich exotic nuclei. Proposed level schemes are presented for 59Tim, 82...

  14. Standard test method for gamma energy emission from fission products in uranium hexafluoride and uranyl nitrate solution

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This test method covers the measurement of gamma energy emitted from fission products in uranium hexafluoride (UF6) and uranyl nitrate solution. It is intended to provide a method for demonstrating compliance with UF6 specifications C 787 and C 996 and uranyl nitrate specification C 788. 1.2 The lower limit of detection is 5000 MeV Bq/kg (MeV/kg per second) of uranium and is the square root of the sum of the squares of the individual reporting limits of the nuclides to be measured. The limit of detection was determined on a pure, aged natural uranium (ANU) solution. The value is dependent upon detector efficiency and background. 1.3 The nuclides to be measured are106Ru/ 106Rh, 103Ru,137Cs, 144Ce, 144Pr, 141Ce, 95Zr, 95Nb, and 125Sb. Other gamma energy-emitting fission nuclides present in the spectrum at detectable levels should be identified and quantified as required by the data quality objectives. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its us...

  15. Parallel computation safety analysis irradiation targets fission product molybdenum in neutronic aspect using the successive over-relaxation algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Susmikanti, Mike, E-mail: mike@batan.go.id [Center for Development of Nuclear Informatics, National Nuclear Energy Agency, PUSPIPTEK, Tangerang (Indonesia); Dewayatna, Winter, E-mail: winter@batan.go.id [Center for Nuclear Fuel Technology, National Nuclear Energy Agency, PUSPIPTEK, Tangerang (Indonesia); Sulistyo, Yos, E-mail: soj@batan.go.id [Center for Nuclear Equipment and Engineering, National Nuclear Energy Agency, PUSPIPTEK, Tangerang (Indonesia)

    2014-09-30

    One of the research activities in support of commercial radioisotope production program is a safety research on target FPM (Fission Product Molybdenum) irradiation. FPM targets form a tube made of stainless steel which contains nuclear-grade high-enrichment uranium. The FPM irradiation tube is intended to obtain fission products. Fission materials such as Mo{sup 99} used widely the form of kits in the medical world. The neutronics problem is solved using first-order perturbation theory derived from the diffusion equation for four groups. In contrast, Mo isotopes have longer half-lives, about 3 days (66 hours), so the delivery of radioisotopes to consumer centers and storage is possible though still limited. The production of this isotope potentially gives significant economic value. The criticality and flux in multigroup diffusion model was calculated for various irradiation positions and uranium contents. This model involves complex computation, with large and sparse matrix system. Several parallel algorithms have been developed for the sparse and large matrix solution. In this paper, a successive over-relaxation (SOR) algorithm was implemented for the calculation of reactivity coefficients which can be done in parallel. Previous works performed reactivity calculations serially with Gauss-Seidel iteratives. The parallel method can be used to solve multigroup diffusion equation system and calculate the criticality and reactivity coefficients. In this research a computer code was developed to exploit parallel processing to perform reactivity calculations which were to be used in safety analysis. The parallel processing in the multicore computer system allows the calculation to be performed more quickly. This code was applied for the safety limits calculation of irradiated FPM targets containing highly enriched uranium. The results of calculations neutron show that for uranium contents of 1.7676 g and 6.1866 g (× 10{sup 6} cm{sup −1}) in a tube, their delta

  16. Synthesis report on the relevant diffusion coefficients of fission products and helium in spent nuclear fuels; Rapport de synthese sur les coefficients de diffusion des produits de fission et de l'helium dans le combustible irradie

    Energy Technology Data Exchange (ETDEWEB)

    Lovera, P.; Ferry, C.; Poinssot, Ch. [CEA Saclay, Dept. de Physico-Chimie (DPC), 91 - Gif sur Yvette (France); Johnson, L. [Nagra, Baden (Switzerland)

    2003-07-01

    This document corresponds to the deliverable D2 of the Work Package 1 of the 'Spent Fuel Stability under repository conditions' (SFS) European project. It constitutes a synthesis report on relevant diffusion coefficients of fission products and helium in spent nuclear fuels at high and low temperatures. Coefficients corresponding to thermally activated diffusion were reviewed from literature data for O, U (self-diffusion coefficients), fission gases and other fission products. Data showed that thermal diffusion was irrelevant at temperatures expected in repository conditions. The occurrence of diffusion enhanced by alpha self-irradiation was studied through different theoretical approaches. A 'best estimate' value of the alpha self-irradiation diffusion coefficient, D (m{sup 2}.s{sup -1}), is proposed. It is extrapolated from enhanced diffusion under irradiation observed in reactor and would be proportional to the volume alpha activity in the spent nuclear fuel, A{sub v} (Bq.m{sup -3}) as: D/A{sub v} {approx_equal} 2.10{sup -41} (m{sup 5})The migration of stable Pb in Oklo's uraninites was studied in order to validate the proposed diffusion coefficient. The obtained value is one order of magnitude higher than the theoretical proposed value. As for He behaviour in spent nuclear fuel, a few data are today available in open literature. The document will be completed as soon as new experimental results are available. (authors)

  17. Delayed Fission Product Gamma-Ray Transmission Through Low Enriched UO2 Fuel Pin Lattices in Air

    Energy Technology Data Exchange (ETDEWEB)

    Trumbull, TH [Rensselaer Polytechnic Inst., Troy, NY (United States)

    2004-10-18

    The transmission of delayed fission-product gamma rays through various arrangements of low-enriched UO2 fuel pin lattices in an air medium was studied. Experimental measurements, point-kernel and Monte Carlo photon transport calculations were performed to demonstrate the shielding effect of ordered lattices of fuel pins on the resulting gamma-ray dose to a detector outside the lattice. The variation of the gamma-ray dose on the outside of the lattice as a function of radial position, the so-called “channeling” effect, was analyzed. Techniques for performing experimental measurements and data reduction at Rensselaer Polytechnic Institute’s Reactor Critical Facility (RCF) were derived. An experimental apparatus was constructed to hold the arrangements of fuel pins for the measurements. A gamma-ray spectroscopy system consisting of a sodium-iodide scintillation detector was used to collect data. Measurements were made with and without a collimator installed. A point-kernel transport code was developed to map the radial dependence of the gamma-ray flux. Input files for the Monte Carlo code, MCNP, were also developed to accurately model the experimental measurements. The results of the calculations were compared to the experimental measurements. In order to determine the delayed fission-product gamma-ray source for the calculations, a technique was developed using a previously written code, DELBG and the reactor state-point data obtained during the experimental measurements. Calculations were performed demonstrating the effects of material homogenization on the gamma-ray transmission through the fuel pin lattice.Homogeneous and heterogeneous calculations were performed for all RCF fuel pin lattices as well as for a typical commercial pressurized water reactor fuel bundle. The results of the study demonstrated the effectiveness of the experimental measurements to isolate the channeling effect of delayed fission-product gamma-rays through lattices of RCF fuel pins

  18. Fission waves can oscillate

    CERN Document Server

    Osborne, Andrew G

    2016-01-01

    Under the right conditions, self sustaining fission waves can form in fertile nuclear materials. These waves result from the transport and absorption of neutrons and the resulting production of fissile isotopes. When these fission, additional neutrons are produced and the chain reaction propagates until it is poisoned by the buildup of fission products. It is typically assumed that fission waves are soliton-like and self stabilizing. However, we show that in uranium, coupling of the neutron field to the 239U->239Np->239Pu decay chain can lead to a Hopf bifurcation. The fission reaction then ramps up and down, along with the wave velocity. The critical driver for the instability is a delay, caused by the half-life of 239U, between the time evolution of the neutron field and the production of 239Pu. This allows the 239Pu to accumulate and burn out in a self limiting oscillation that is characteristic of a Hopf bifurcation. Time dependent results are obtained using a numerical implementation of a reduced order r...

  19. Measurement of fission products β decay properties using a total absorption spectrometer

    Directory of Open Access Journals (Sweden)

    Zakari-Issoufou A.-A.

    2013-12-01

    Full Text Available In a nuclear reactor, the β decay of fission fragments is at the origin of decay heat and antineutrino flux. These quantities are not well known while they are very important for reactor safety and for our understanding of neutrino physics. One reason for the discrepancies observed in the estimation of the decay heat and antineutrinos flux coming from reactors could be linked with the Pandemonium effect. New measurements have been performed at the JYFL facility of Jyväskylä with a Total Absorption Spectrometer (TAS in order to circumvent this effect. An overview of the TAS technique and first results from the 2009 measurement campaign will be presented.

  20. Delayed neutron spectra and their uncertainties in fission product summation calculations

    Energy Technology Data Exchange (ETDEWEB)

    Miyazono, T.; Sagisaka, M.; Ohta, H.; Oyamatsu, K.; Tamaki, M. [Nagoya Univ. (Japan)

    1997-03-01

    Uncertainties in delayed neutron summation calculations are evaluated with ENDF/B-VI for 50 fissioning systems. As the first step, uncertainty calculations are performed for the aggregate delayed neutron activity with the same approximate method as proposed previously for the decay heat uncertainty analyses. Typical uncertainty values are about 6-14% for {sup 238}U(F) and about 13-23% for {sup 243}Am(F) at cooling times 0.1-100 (s). These values are typically 2-3 times larger than those in decay heat at the same cooling times. For aggregate delayed neutron spectra, the uncertainties would be larger than those for the delayed neutron activity because much more information about the nuclear structure is still necessary. (author)

  1. Molecular Dynamics Simulation of Thermal Transport in UO2 Containing Uranium, Oxygen, and Fission-product Defects

    Science.gov (United States)

    Liu, X.-Y.; Cooper, M. W. D.; McClellan, K. J.; Lashley, J. C.; Byler, D. D.; Bell, B. D. C.; Grimes, R. W.; Stanek, C. R.; Andersson, D. A.

    2016-10-01

    Uranium dioxide (UO2 ) is the most commonly used fuel in light-water nuclear reactors and thermal conductivity controls the removal of heat produced by fission, thereby governing fuel temperature during normal and accident conditions. The use of fuel performance codes by the industry to predict operational behavior is widespread. A primary source of uncertainty in these codes is thermal conductivity, and optimized fuel utilization may be possible if existing empirical models are replaced with models that incorporate explicit thermal-conductivity-degradation mechanisms during fuel burn up. This approach is able to represent the degradation of thermal conductivity due to each individual defect type, rather than the overall burn-up measure typically used, which is not an accurate representation of the chemical or microstructure state of the fuel that actually governs thermal conductivity and other properties. To generate a mechanistic thermal conductivity model, molecular dynamics (MD) simulations of UO2 thermal conductivity including representative uranium and oxygen defects and fission products are carried out. These calculations employ a standard Buckingham-type interatomic potential and a potential that combines the many-body embedded-atom-method potential with Morse-Buckingham pair potentials. Potential parameters for UO2 +x and ZrO2 are developed for the latter potential. Physical insights from the resonant phonon-spin-scattering mechanism due to spins on the magnetic uranium ions are introduced into the treatment of the MD results, with the corresponding relaxation time derived from existing experimental data. High defect scattering is predicted for Xe atoms compared to that of La and Zr ions. Uranium defects reduce the thermal conductivity more than oxygen defects. For each defect and fission product, scattering parameters are derived for application in both a Callaway model and the corresponding high-temperature model typically used in fuel-performance codes

  2. Fission product release assessment for end fitting failure in Candu reactor loaded with CANFLEX-NU fuel bundles

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Dirk Joo; Jeong, Chang Joon; Lee, Kang Moon; Suk, Ho Chun [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1997-12-31

    Fission product release (FPR) assessment for End Fitting Failure (EFF) in CANDU reactor loaded with CANFLEX-natural uranium (NU) fuel bundles has been performed. The predicted results are compared with those for the reactor loaded with standard 37-element bundles. The total channel I-131 release at the end of transient for EFF accident is calculated to be 380.8 TBq and 602.9 TBq for the CANFLEX bundle and standard bundle channel cases, respectively. They are 4.9% and 7.9% of total inventory, respectively. The lower total releases of the CANFLEX bundle O6 channel are attributed to the lower initial fuel temperatures caused by the lower linear element power of the CANFLEX bundle compared with the standard bundle. 4 refs., 1 fig., 4 tabs. (Author)

  3. Determination of critical assembly absolute power using post-irradiation activation measurement of week-lived fission products.

    Science.gov (United States)

    Košťál, Michal; Švadlenková, Marie; Milčák, Ján; Rypar, Vojtěch; Koleška, Michal

    2014-07-01

    The work presents a detailed comparison of calculated and experimentally determined net peak areas of longer-living fission products after 100 h irradiation on a reactor with power of ~630 W and several days cooling. Specifically the nuclides studied are (140)Ba, (103)Ru, (131)I, (141)Ce, (95)Zr. The good agreement between the calculated and measured net peak areas, which is better than in determination using short lived (92)Sr, is reported. The experiment was conducted on the VVER-1000 mock-up installed on the LR-0 reactor. The Monte Carlo approach has been used for calculations. The influence of different data libraries on results of calculation is discussed as well.

  4. Thermal transport in UO2 with defects and fission products by molecular dynamics simulations

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiang-Yang [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Cooper, Michael William Donald [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mcclellan, Kenneth James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lashley, Jason Charles [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Byler, Darrin David [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Stanek, Christopher Richard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Andersson, Anders David Ragnar [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-10-14

    The importance of the thermal transport in nuclear fuel has motivated a wide range of experimental and modelling studies. In this report, the reduction of thermal transport in UO2 due to defects and fission products has been investigated using non-equilibrium MD simulations, with two sets of empirical potentials for studying the degregation of UO2 thermal conductivity including a Buckingham type interatomic potential and a recently developed EAM type interatomic potential. Additional parameters for U5+ and Zr4+ in UO2 have been developed for the EAM potential. The thermal conductivity results from MD simulations are then corrected for the spin-phonon scattering through Callaway model formulations. To validate the modelling results, comparison was made with experimental measurements on single crystal hyper-stoichiometric UO2+x samples.

  5. Nanocrystalline SiC and Ti3SiC2 Alloys for Reactor Materials: Diffusion of Fission Product Surrogates

    Energy Technology Data Exchange (ETDEWEB)

    Henager, Charles H.; Jiang, Weilin

    2014-11-01

    MAX phases, such as titanium silicon carbide (Ti3SiC2), have a unique combination of both metallic and ceramic properties, which make them attractive for potential nuclear applications. Ti3SiC2 has been suggested in the literature as a possible fuel cladding material. Prior to the application, it is necessary to investigate diffusivities of fission products in the ternary compound at elevated temperatures. This study attempts to obtain relevant data and make an initial assessment for Ti3SiC2. Ion implantation was used to introduce fission product surrogates (Ag and Cs) and a noble metal (Au) in Ti3SiC2, SiC, and a dual-phase nanocomposite of Ti3SiC2/SiC synthesized at PNNL. Thermal annealing and in-situ Rutherford backscattering spectrometry (RBS) were employed to study the diffusivity of the various implanted species in the materials. In-situ RBS study of Ti3SiC2 implanted with Au ions at various temperatures was also performed. The experimental results indicate that the implanted Ag in SiC is immobile up to the highest temperature (1273 K) applied in this study; in contrast, significant out-diffusion of both Ag and Au in MAX phase Ti3SiC2 occurs during ion implantation at 873 K. Cs in Ti3SiC2 is found to diffuse during post-irradiation annealing at 973 K, and noticeable Cs release from the sample is observed. This study may suggest caution in using Ti3SiC2 as a fuel cladding material for advanced nuclear reactors operating at very high temperatures. Further studies of the related materials are recommended.

  6. The methodical substantiation of measures to improve the use of basic production assets of the enterprise

    Directory of Open Access Journals (Sweden)

    Korol Svetlana Anatolevna

    2013-07-01

    Full Text Available The method of calculating the performance measures to improve the use of basic production assets of the enterprise: production cost, production volume, number of additional workers, depreciation and amortization.

  7. I-NERI ANNUAL TECHNICAL PROGRESS REPORT: 2006-002-K, Separation of Fission Products from Molten LiCl-KCl Salt Used for Electrorefining of Metal Fuels

    Energy Technology Data Exchange (ETDEWEB)

    S. Frank

    2009-09-01

    An attractive alternative to the once-through disposal of electrorefiner salt is to selectively remove the active fission products from the salt and recycle the salt back to the electrorefiner (ER). This would allow salt reuse for some number of cycles before ultimate disposal of the salt in a ceramic waste form. Reuse of ER salt would, thus, greatly reduce the volume of ceramic waste produced during the pyroprocessing of spent nuclear fuel. This final portion of the joint I-NERI research project is to demonstrate the separation of fission products from molten ER salt by two methods previously selected during phase two (FY-08) of this project. The two methods selected were salt/zeolite contacting and rare-earth fission product precipitation by oxygen bubbling. The ER salt used in these tests came from the Mark-IV electrorefiner used to anodically dissolved driver fuel from the EBR-II reactor on the INL site. The tests were performed using the Hot Fuel Dissolution Apparatus (HFDA) located in the main cell of the Hot Fuels Examination Facility (HFEF) at the Materials and Fuels complex on the INL site. Results from these tests were evaluated during a joint meeting of KAERI and INL investigators to provide recommendations as to the future direction of fission product removal from electrorefiner salt that accumulate during spent fuel treatment. Additionally, work continued on kinetic measurements of surrogate quaternary salt systems to provide fundamental kinetics on the ion exchange system and to expand the equilibrium model system developed during the first two phases of this project. The specific objectives of the FY09 I-NERI research activities at the INL include the following: • Perform demonstration tests of the selected KAERI precipitation and INL salt/zeolite contacting processes for fission product removal using radioactive, fission product loaded ER salt • Continue kinetic studies of the quaternary Cs/Sr-LiCl-KCl system to determine the rate of ion

  8. A MODEL FOR PREDICTING FISSION PRODUCT ACTIVITIES IN REACTOR COOLANT: APPLICATION OF MODEL FOR ESTIMATING I-129 LEVELS IN RADIOACTIVE WASTE

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, B.J.; Husain, A.

    2003-02-27

    A general model was developed to estimate the activities of fission products in reactor coolant and hence to predict a value for the I-129/Cs-137 scaling factor; the latter can be applied along with measured Cs-137 activities to estimate I-129 levels in reactor waste. The model accounts for fission product release from both defective fuel rods and uranium contamination present on in-core reactor surfaces. For simplicity, only the key release mechanisms were modeled. A mass balance, considering the two fuel source terms and a loss term due to coolant cleanup was solved to estimate fission product activity in the primary heat transport system coolant. Steady state assumptions were made to solve for the activity of shortlived fission products. Solutions for long-lived fission products are time-dependent. Data for short-lived radioiodines I-131, I-132, I-133, I-134 and I-135 were analyzed to estimate model parameters for I-129. The estimated parameter values were then used to determine I-1 29 coolant activities. Because of the chemical affinity between iodine and cesium, estimates of Cs-137 coolant concentrations were also based on parameter values similar to those for the radioiodines; this assumption was tested by comparing measured and predicted Cs-137 coolant concentrations. Application of the derived model to Douglas Point and Darlington Nuclear Generating Station plant data yielded estimates for I-129/I-131 and I-129/Cs-137 which are consistent with values reported for pressurized water reactors (PWRs) and boiling water reactors (BWRs). The estimated magnitude for the I-129/Cs-137 ratio was 10-8 - 10-7.

  9. Ternary fission

    Indian Academy of Sciences (India)

    M Balasubramaniam; K R Vijayaraghavan; C Karthikraj

    2015-09-01

    We present the ternary fission of 252Cf and 236U within a three-cluster model as well as in a level density approach. The competition between collinear and equatorial geometry is studied by calculating the ternary fragmentation potential as a function of the angle between the lines joining the stationary middle fragment and the two end fragments. The obtained results for the 16O accompanying ternary fission indicate that collinear configuration is preferred to equatorial configuration. Further, for all the possible third fragments, the potential energy surface (PES) is calculated corresponding to an arrangement in which the heaviest and the lightest fragments are considered at the end in a collinear configuration. The PES reveals several possible ternary modes including true ternary modes where the three fragments are of similar size. The complete mass distributions of Si and Ca which accompanied ternary fission of 236U is studied within a level density picture. The obtained results favour several possible ternary combinations.

  10. Modernizing the Fission Basis

    Science.gov (United States)

    Tonchev, Anton; Henderson, Roger; Schunck, Nicolas; Sroyer, Mark; Vogt, Ramona

    2016-09-01

    In 1939, Niels Bohr and John Wheeler formulated a theory of neutron-induced nuclear fission based on the hypothesis of the compound nucleus. Their theory, the so-called ``Bohr hypothesis,'' is still at the heart of every theoretical fission model today and states that the decay of a compound nucleus for a given excitation energy, spin, and parity is independent of its formation. We propose the first experiment to validate to 1-2% absolute uncertainties the practical consequences of the Bohr hypothesis during induced nuclear fission. We will compare the fission product yields (FPYs) of the same 240Pu compound nucleus produced via two different reactions (i) n+239Pu and (ii) γ+240 Pu. These high-precision FPYs measurements will be extremely beneficial for our fundamental understanding of the nuclear fission process and nuclear reactions from first principles. This work was performed under the auspices of US DOE by LLNL under Contract DE-AC52-07NA27344. Funding was provided via the LDRD-ERD-069 project.

  11. Development of ionization technique for measurement of fast neutron induced fission products yields of {sup 237}Np

    Energy Technology Data Exchange (ETDEWEB)

    Goverdovski, A.A.; Khryachkov, V.A.; Ketlerov, V.V.; Mitrofanov, V.F.; Ostapenko, Yu.B.; Semenova, N.N.; Fomichev, A.N.; Rodina, L.F. [Institute of Physics and Power Engineering, Obninsk (Russian Federation)

    1997-03-01

    Twin gridded ionization chamber and corresponding software was designed for measurements of masses, kinetic energies and nuclear charges of fission fragments from fast neutron induced fission of {sup 237}Np. The ionization detector design, electronics, data acquisition and processing system and the test results are presented in this paper. (J.P.N.)

  12. Radiochemistry and the Study of Fission

    Energy Technology Data Exchange (ETDEWEB)

    Rundberg, Robert S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-11-14

    These are slides from a lecture given at UC Berkeley. Radiochemistry has been used to study fission since it’ discovery. Radiochemical methods are used to determine cumulative mass yields. These measurements have led to the two-mode fission hypothesis to model the neutron energy dependence of fission product yields. Fission product yields can be used for the nuclear forensics of nuclear explosions. The mass yield curve depends on both the fuel and the neutron spectrum of a device. Recent studies have shown that the nuclear structure of the compound nucleus can affect the mass yield distribution. The following topics are covered: In the beginning: the discovery of fission; forensics using fission products: what can be learned from fission products, definitions of R-values and Q-values, fission bases, K-factors and fission chambers, limitations; the neutron energy dependence of the mass yield distribution (the two mode fission hypothesis); the influence of nuclear structure on the mass yield distribution. In summary: Radiochemistry has been used to study fission since it’s discovery. Radiochemical measurement of fission product yields have provided the highest precision data for developing fission models and for nuclear forensics. The two-mode fission hypothesis provides a description of the neutron energy dependence of the mass yield curve. However, data is still rather sparse and more work is needed near second and third chance fission. Radiochemical measurements have provided evidence for the importance of nuclear states in the compound nucleus in predicting the mass yield curve in the resonance region.

  13. Spallation and fission products in the (p+{sup 179}Hf) and (p+{sup nat}Hf) reactions

    Energy Technology Data Exchange (ETDEWEB)

    Karamian, S.A. [Joint Institute for Nuclear Research, Moscow Region, Dubna 141980 (Russian Federation); Ur, C.A. [Horia Hulubei National Institute of Physics and Nuclear Engineering, P.O. Box MG-6, Bucharest 077125 (Romania); Induced Gamma Emission Foundation, P.O. Box 34-81, Bucharest 010044 (Romania)], E-mail: ur@pd.infn.it; Adam, J. [Joint Institute for Nuclear Research, Moscow Region, Dubna 141980 (Russian Federation); Institute of Nuclear Physics, Rez, Prague CZ-25068 (Czech Republic); Kalinnikov, V.G.; Lebedev, N.A.; Vostokin, G.K. [Joint Institute for Nuclear Research, Moscow Region, Dubna 141980 (Russian Federation); Collins, C.B. [Center for Quantum Electronics, University of Texas at Dallas, Richardson, TX 75083 (United States); Popescu, I.I. [Induced Gamma Emission Foundation, P.O. Box 34-81, Bucharest 010044 (Romania)

    2009-03-01

    Production of Hf and Lu high-spin isomers has been experimentally studied in spallation reactions induced by intermediate energy protons. Targets of enriched {sup 179}Hf (91%) and {sup nat}Hf were bombarded with protons of energy in the range from 90 to 650 MeV provided by the internal beam of the Dubna Phasotron synchrocyclotron. The activation yields of the reaction products were measured by using the {gamma}-ray spectroscopy and radiochemistry methods. The production cross-sections obtained for the {sup 179m2}Hf, {sup 178m2}Hf and {sup 177m}Lu isomers are similar to the previously measured values from the spallation of Ta, Re and W targets. Therefore, the reactions involving emission of only a few nucleons, like (p,p'), (p,p'n) and (p,2pn), can transfer high enough angular momentum to the final residual nuclei with reasonable large cross-sections. A significant gain in the isomeric yields was obtained when enriched {sup 179}Hf targets were used. The mass distribution of the residual nuclei was measured over a wide range of masses and the fission-to-spallation ratio could be deduced as a function of the projectile energy. Features of the reaction mechanism are briefly discussed.

  14. Methodology and experimental setup for measuring short-lives fission product yields in actinides induced fission by charged particles; Metodologia e montagem experimental para a medicao de rendimentos de produtos de fissao de meia vida curta na fissao de actinideos por particulas carregadas

    Energy Technology Data Exchange (ETDEWEB)

    Bellido, A.V.

    1995-07-01

    The theoretical principles and the laboratory set-up for the fission products yields measurements are described. The procedures for the experimental determinations are explain in detail. (author). 43 refs., 5 figs.

  15. Ionizing radiation accelerates Drp1-dependent mitochondrial fission, which involves delayed mitochondrial reactive oxygen species production in normal human fibroblast-like cells

    Energy Technology Data Exchange (ETDEWEB)

    Kobashigawa, Shinko, E-mail: kobashin@nagasaki-u.ac.jp [Atomic Bomb Disease Institute, Course of Life Sciences and Radiation Research, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki 852-8523 (Japan); Suzuki, Keiji; Yamashita, Shunichi [Atomic Bomb Disease Institute, Course of Life Sciences and Radiation Research, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki 852-8523 (Japan)

    2011-11-04

    Highlights: Black-Right-Pointing-Pointer We report first time that ionizing radiation induces mitochondrial dynamic changes. Black-Right-Pointing-Pointer Radiation-induced mitochondrial fission was caused by Drp1 localization. Black-Right-Pointing-Pointer We found that radiation causes delayed ROS from mitochondria. Black-Right-Pointing-Pointer Down regulation of Drp1 rescued mitochondrial dysfunction after radiation exposure. -- Abstract: Ionizing radiation is known to increase intracellular level of reactive oxygen species (ROS) through mitochondrial dysfunction. Although it has been as a basis of radiation-induced genetic instability, the mechanism involving mitochondrial dysfunction remains unclear. Here we studied the dynamics of mitochondrial structure in normal human fibroblast like cells exposed to ionizing radiation. Delayed mitochondrial O{sub 2}{sup {center_dot}-} production was peaked 3 days after irradiation, which was coupled with accelerated mitochondrial fission. We found that radiation exposure accumulated dynamin-related protein 1 (Drp1) to mitochondria. Knocking down of Drp1 expression prevented radiation induced acceleration of mitochondrial fission. Furthermore, knockdown of Drp1 significantly suppressed delayed production of mitochondrial O{sub 2}{sup {center_dot}-}. Since the loss of mitochondrial membrane potential, which was induced by radiation was prevented in cells knocking down of Drp1 expression, indicating that the excessive mitochondrial fission was involved in delayed mitochondrial dysfunction after irradiation.

  16. Fission Spectrum

    Science.gov (United States)

    Bloch, F.; Staub, H.

    1943-08-18

    Measurements of the spectrum of the fission neutrons of 25 are described, in which the energy of the neutrons is determined from the ionization produced by individual hydrogen recoils. The slow neutrons producing fission are obtained by slowing down the fast neutrons from the Be-D reaction of the Stanford cyclotron. In order to distinguish between fission neutrons and the remaining fast cyclotron neutrons both the cyclotron current and the pusle amplifier are modulated. A hollow neutron container, in which slow neutrons have a lifetime of about 2 milliseconds, avoids the use of large distances. This method results in much higher intensities than the usual modulation arrangement. The results show a continuous distribution of neutrons with a rather wide maximum at about 0.8 MV falling off to half of its maximum value at 2.0 MV. The total number of netrons is determined by comparison with the number of fission fragments. The result seems to indicate that only about 30% of the neutrons have energies below .8 MV. Various tests are described which were performed in order to rule out modification of the spectrum by inelastic scattering. Decl. May 4, 1951

  17. Temperature dependent fission fragment distribution in the Langevin equation

    Institute of Scientific and Technical Information of China (English)

    WANG Kun; MA Yu-Gang; ZHENG Qing-Shan; CAI Xiang-Zhou; FANG De-Qing; FU Yao; LU Guang-Cheng; TIAN Wen-Dong; WANG Hong-Wei

    2009-01-01

    The temperature dependent width of the fission fragment distributions was simulated in the Langevin equation by taking two-parameter exponential form of the fission fragment mass variance at scission point for each fission event. The result can reproduce experimental data well, and it permits to make reliable estimate for unmeasured product yields near symmetry fission.

  18. Spallation reaction study for fission products in nuclear waste: Cross section measurements for 137Cs and 90Sr on proton and deuteron

    Science.gov (United States)

    Wang, H.; Otsu, H.; Sakurai, H.; Ahn, D. S.; Aikawa, M.; Doornenbal, P.; Fukuda, N.; Isobe, T.; Kawakami, S.; Koyama, S.; Kubo, T.; Kubono, S.; Lorusso, G.; Maeda, Y.; Makinaga, A.; Momiyama, S.; Nakano, K.; Niikura, M.; Shiga, Y.; Söderström, P.-A.; Suzuki, H.; Takeda, H.; Takeuchi, S.; Taniuchi, R.; Watanabe, Ya.; Watanabe, Yu.; Yamasaki, H.; Yoshida, K.

    2016-03-01

    We have studied spallation reactions for the fission products 137Cs and 90Sr for the purpose of nuclear waste transmutation. The spallation cross sections on the proton and deuteron were obtained in inverse kinematics for the first time using secondary beams of 137Cs and 90Sr at 185 MeV/nucleon at the RIKEN Radioactive Isotope Beam Factory. The target dependence has been investigated systematically, and the cross-section differences between the proton and deuteron are found to be larger for lighter spallation products. The experimental data are compared with the PHITS calculation, which includes cascade and evaporation processes. Our results suggest that both proton- and deuteron-induced spallation reactions are promising mechanisms for the transmutation of radioactive fission products.

  19. Spallation reaction study for fission products in nuclear waste: Cross section measurements for 137Cs and 90Sr on proton and deuteron

    Directory of Open Access Journals (Sweden)

    H. Wang

    2016-03-01

    Full Text Available We have studied spallation reactions for the fission products 137Cs and 90Sr for the purpose of nuclear waste transmutation. The spallation cross sections on the proton and deuteron were obtained in inverse kinematics for the first time using secondary beams of 137Cs and 90Sr at 185 MeV/nucleon at the RIKEN Radioactive Isotope Beam Factory. The target dependence has been investigated systematically, and the cross-section differences between the proton and deuteron are found to be larger for lighter spallation products. The experimental data are compared with the PHITS calculation, which includes cascade and evaporation processes. Our results suggest that both proton- and deuteron-induced spallation reactions are promising mechanisms for the transmutation of radioactive fission products.

  20. Spallation reaction study for fission products in nuclear waste: Cross section measurements for {sup 137}Cs and {sup 90}Sr on proton and deuteron

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H., E-mail: wanghe@ribf.riken.jp [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Otsu, H.; Sakurai, H.; Ahn, D.S. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Aikawa, M. [Faculty of Science, Hokkaido University, Sapporo 060-0810 (Japan); Doornenbal, P.; Fukuda, N.; Isobe, T. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Kawakami, S. [Department of Applied Physics, University of Miyazaki, Miyazaki 889-2192 (Japan); Koyama, S. [Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 (Japan); Kubo, T.; Kubono, S.; Lorusso, G. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Maeda, Y. [Department of Applied Physics, University of Miyazaki, Miyazaki 889-2192 (Japan); Makinaga, A. [Graduate School of Medicine, Hokkaido University, North-14, West-5, Kita-ku, Sapporo 060-8648 (Japan); Momiyama, S. [Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 (Japan); Nakano, K. [Department of Advanced Energy Engineering Science, Kyushu University, Kasuga, Fukuoka 816-8580 (Japan); Niikura, M. [Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 (Japan); Shiga, Y. [Department of Physics, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501 (Japan); RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Söderström, P.-A. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); and others

    2016-03-10

    We have studied spallation reactions for the fission products {sup 137}Cs and {sup 90}Sr for the purpose of nuclear waste transmutation. The spallation cross sections on the proton and deuteron were obtained in inverse kinematics for the first time using secondary beams of {sup 137}Cs and {sup 90}Sr at 185 MeV/nucleon at the RIKEN Radioactive Isotope Beam Factory. The target dependence has been investigated systematically, and the cross-section differences between the proton and deuteron are found to be larger for lighter spallation products. The experimental data are compared with the PHITS calculation, which includes cascade and evaporation processes. Our results suggest that both proton- and deuteron-induced spallation reactions are promising mechanisms for the transmutation of radioactive fission products.

  1. Use of electron beams for the production of radioactive nuclei through photo-fission; Utilisation de faisceaux d'electrons pour la production des noyaux radioactifs par photo-fission

    Energy Technology Data Exchange (ETDEWEB)

    M' garrech, Slah

    2004-09-01

    The IPN (institute of nuclear physics) of Orsay decided to build a linear accelerator in order to produce an electron beam of 50 MeV energy and of 10 {mu}A average intensity. It is the ALTO project (Linear Accelerator near the Tandem of Orsay). This project will be dedicated to the production of the radioactive ions using the photo-fission process. The central topic of this thesis is the study of the beam dynamics of the ALTO facility. The first part presents studies concerning the injector. The simulations made with the simulation code PARMELA allowed the optimization of the characteristics of pre-buncher (dephasing HF, accelerating field peak...) to obtain a good bunching factor at the entrance of the buncher and at the entrance of the accelerating section according to the distance separating the two systems. The second part of this thesis is related to measurements of transverse emittance of the beam at the buncher exit. The three gradients method has been selected and the optical system used is a solenoid. The results obtained are in good agreement with former measurements. Finally a calculation of the beam line was carried out to optimize the transport of the beam to the PARRNe target without degrading its characteristics. The calculation codes that have been used are BETA and TRACE-WIN. (author)

  2. Irradiation effects and diffusion of fission products (cesium and iodine) in silicon carbide; Effets d'irradiation et diffusion des produits de fission (cesium et iode) dans le carbure de silicium

    Energy Technology Data Exchange (ETDEWEB)

    Audren, A

    2007-03-15

    Silicon carbide is envisaged as a cladding material for the nuclear fuel in the fourth generation reactors. The aim of this work is to study the capacity to retain fission products and the structure evolution of this material under the combined effects of temperature and irradiation. The low energy ion implantations and the incorporation of stable analogues of fission products (Cs and I) in single crystalline 6H-SiC samples were performed by using the ion implanter or the accelerator of the CSNSM. The high energy heavy ion irradiations were made at GANIL. The evolution of the implanted ion profiles and the crystal structure were studied by RBS and Channeling. Complementary information were obtained by using the UV-visible absorption spectroscopy. The low energy ion implantations at room temperature induce a fast structural damage in the crystal. On the other hand, it is possible to attain a small disorder rate in the crystal during implantation by increasing the implantation temperature (600 C). The high energy heavy ion irradiations do not damage the SiC crystals. On the contrary, they cause an annealing of the disorder created by the low energy implantations. The implanted ions (I) do not diffuse during low or high energy ion irradiations at room temperature and at 600 C. However, a diffusion of Cs ions was observed during a post-implantation annealing at 1300 C. At this temperature, the crystal which had an extended amorphous layer starts to recover a single-crystal structure. (author)

  3. Determination of the fission barrier height in fission of heavy radioactive beams induced by the (d,p)-transfer

    CERN Multimedia

    A theoretical framework is described, allowing to determine the fission barrier height using the observed cross sections of fission induced by the (d,p)-transfer with accuracy, which is not achievable in another type of low-energy fission of neutron-deficient nuclei, the $\\beta$-delayed fission. The primary goal is to directly determine the fission barrier height of proton-rich fissile nuclei, preferably using the radio-active beams of isotopes of odd elements, and thus confirm or exclude the low values of fission barrier heights, typically extracted using statistical calculations in the compound nucleus reactions at higher excitation energies. Calculated fission cross sections in transfer reactions of the radioactive beams show sufficient sensitivity to fission barrier height. In the probable case that fission rates will be high enough, mass asymmetry of fission fragments can be determined. Results will be relevant for nuclear astrophysics and for production of super-heavy nuclei. Transfer induced fission of...

  4. Fission dynamics within time-dependent Hartree-Fock: deformation-induced fission

    CERN Document Server

    Goddard, P M; Rios, A

    2015-01-01

    Background: Nuclear fission is a complex large-amplitude collective decay mode in heavy nuclei. Microscopic density functional studies of fission have previously concentrated on adiabatic approaches based on constrained static calculations ignoring dynamical excitations of the fissioning nucleus, and the daughter products. Purpose: To explore the ability of dynamic mean-field methods to describe fast fission processes beyond the fission barrier, using the nuclide $^{240}$Pu as an example. Methods: Time-dependent Hartree-Fock calculations based on the Skyrme interaction are used to calculate non-adiabatic fission paths, beginning from static constrained Hartree-Fock calculations. The properties of the dynamic states are interpreted in terms of the nature of their collective motion. Fission product properties are compared to data. Results: Parent nuclei constrained to begin dynamic evolution with a deformation less than the fission barrier exhibit giant-resonance-type behaviour. Those beginning just beyond the ...

  5. The maximum entropy production principle: two basic questions.

    Science.gov (United States)

    Martyushev, Leonid M

    2010-05-12

    The overwhelming majority of maximum entropy production applications to ecological and environmental systems are based on thermodynamics and statistical physics. Here, we discuss briefly maximum entropy production principle and raises two questions: (i) can this principle be used as the basis for non-equilibrium thermodynamics and statistical mechanics and (ii) is it possible to 'prove' the principle? We adduce one more proof which is most concise today.

  6. Investigation of the Distribution of Fission Products Silver, Palladium and Cadmium in Neutron Irradiated SIC using a Cs Corrected HRTEM

    Energy Technology Data Exchange (ETDEWEB)

    I. J. van Rooyen; E. Olivier; J. H Neethlin

    2014-10-01

    Electron microscopy examinations of selected coated particles from the first advanced gas reactor experiment (AGR-1) at Idaho National Laboratory (INL) provided important information on fission product distribution and chemical composition. Furthermore, recent research using STEM analysis led to the discovery of Ag at SiC grain boundaries and triple junctions. As these Ag precipitates were nano-sized, high resolution transmission electron microscopy (HRTEM) examination was used to provide more information at the atomic level. This paper describes some of the first HRTEM results obtained by examining a particle from Compact 4-1-1, which was irradiated to an average burnup of 19.26% fissions per initial metal atom (FIMA), a time average, volume-averaged temperature of 1072°C; a time average, peak temperature of 1182°C and an average fast fluence of 4.13 x 1021 n/cm2. Based on gamma analysis, it is estimated that this particle may have released as much as 10% of its available Ag-110m inventory during irradiation. The HRTEM investigation focused on Ag, Pd, Cd and U due to the interest in Ag transport mechanisms and possible correlation with Pd, Ag and U previously found. Additionally, Compact 4-1-1 contains fuel particles fabricated with a different fuel carrier gas composition and lower deposition temperatures for the SiC layer relative to the Baseline fabrication conditions, which are expected to reduce the concentration of SiC defects resulting from uranium dispersion. Pd, Ag, and Cd were found to co-exist in some of the SiC grain boundaries and triple junctions whilst U was found to be present in the micron-sized precipitates as well as separately in selected areas at grain boundaries. This study confirmed the presence of Pd both at inter- and intragranular positions; in the latter case specifically at stacking faults. Small Pd nodules were observed at a distance of about 6.5 micron from the inner PyC/SiC interface.

  7. Current research and development activities on fission products and hydrogen risk after the accident at Fukushima Daiichi nuclear power station

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Takeshi; Hoshi, Harutaka; Hotta, Akitoshi [Regulatory Standard and Research Department, Secretariat of Nuclear Regulation Authority, Tokyo (Japan)

    2015-02-15

    After the Fukushima Daiichi nuclear power plant (NPP) accident, new regulatory requirements were enforced in July 2013 and a backfit was required for all existing nuclear power plants. It is required to take measures to prevent severe accidents and mitigate their radiological consequences. The Regulatory Standard and Research Department, Secretariat of Nuclear Regulation Authority (S/NRA/R) has been conducting numerical studies and experimental studies on relevant severe accident phenomena and countermeasures. This article highlights fission product (FP) release and hydrogen risk as two major areas. Relevant activities in the S/NRA/R are briefly introduced, as follows: 1. For FP release: Identifying the source terms and leak mechanisms is a key issue from the viewpoint of understanding the progression of accident phenomena and planning effective countermeasures that take into account vulnerabilities of containment under severe accident conditions. To resolve these issues, the activities focus on wet well venting, pool scrubbing, iodine chemistry (in-vessel and ex-vessel), containment failure mode, and treatment of radioactive liquid effluent. 2. For hydrogen risk: because of three incidents of hydrogen explosion in reactor buildings, a comprehensive reinforcement of the hydrogen risk management has been a high priority topic. Therefore, the activities in evaluation methods focus on hydrogen generation, hydrogen distribution, and hydrogen combustion.

  8. Designing an upgrade of the Medley setup for light-ion production and fission cross-section measurements

    CERN Document Server

    Jansson, Kaj; Al-Adili, Ali; Hjalmarsson, Anders; Andersson-Sundén, Erik; Prokofiev, Alexander V; Tarrío, Diego; Pomp, Stephan

    2015-01-01

    Measurements of neutron-induced fission cross sections and light-ion production are planned in the energy range 1-40 MeV at the upcoming Neutrons For Science (NFS) facility. In order to prepare our detector setup for the neutron beam with continuous energy spectrum, a simulation software was written using the Geant4 toolkit for both measurement situations. The neutron energy range around 20 MeV is troublesome when it comes to the cross sections used by Geant4 since data-driven cross sections are only available below 20 MeV but not above, where they are based on semi-empirical models. Several customisations were made to the standard classes in Geant4 in order to produce consistent results over the whole simulated energy range. Expected uncertainties are reported for both types of measurements. The simulations have shown that a simultaneous precision measurement of the three standard cross sections H(n,n), $^{235}$U(n,f) and $^{238}$U(n,f) relative to each other is feasible using a triple layered target. As hig...

  9. On the effects of fission product noble metal inclusions on the kinetics of radiation induced dissolution of spent nuclear fuel

    Science.gov (United States)

    Trummer, Martin; Nilsson, Sara; Jonsson, Mats

    2008-08-01

    Radiation induced oxidative dissolution of UO 2 is a key process for the safety assessment of future geological repositories for spent nuclear fuel. This process is expected to govern the rate of radionuclide release to the biosphere. In this work, we have studied the catalytic effects of fission product noble metal inclusions on the kinetics of radiation induced dissolution of spent nuclear fuel. The experimental studies were performed using UO 2 pellets containing 0%, 0.1%, 1% and 3% Pd as a model for spent nuclear fuel. H 2O 2 was used as a model for radiolytical oxidants (previous studies have shown that H 2O 2 is the most important oxidant in such systems). The pellets were immersed in aqueous solution containing H 2O 2 and HCO3- and the consumption of H 2O 2 and the dissolution of uranium were analyzed as a function of H 2 pressure (0-40 bar). The noble metal inclusions were found to catalyze oxidation of UO 2 as well as reduction of surface bound oxidized UO 2 by H 2. In both cases the rate of the process increases with increasing Pd content. The reduction process was found to be close to diffusion controlled. This process can fully account for the inhibiting effect of H 2 observed in several studies on spent nuclear fuel dissolution.

  10. Fission products and structural materials release, transport and containment behaviour in Phebus FPT-0 and FPT-1

    Energy Technology Data Exchange (ETDEWEB)

    Hanniet, N.; Garnier, Y.; Jacquemain, D. [Institut de Protection et de Surete Nucleaire - IPSN, Departement de Recherches en Securite - DRS, CEA Cadarache - F 13108 Saint Paul Lez Durance (France)

    1999-07-01

    The Phebus F.P. program is a wide international effort to investigate, through a series of in-pile integral experiments, LWR severe accident phenomena, in particular bundle degradation and the subsequent release and transport of radioactive materials up to the containment. Two tests simulating a low pressure cold leg break under a steam rich environment have already been successfully performed: FPT-0 in December 1993 with trace irradiated fuel and FPT-1 in July 1996 with re-irradiated BR3 fuel. Both tests have provided experimental data of high interest, particularly in the field of fission products and structural materials release from the fuel bundle, transport in the reactor coolant system (RCS) and behaviour in the containment. The analysis of FPT-1 is currently in progress, nevertheless main observations made for FPT-10 are confirmed by first FPT-1 results, i.e.: - the main mass transport phases through the RCS correspond to bundle degradation events (fuel oxidation, material re-location, pool formation); - significant amount of gaseous iodine are injected in the model containment during bundle oxidation phases; - the aerosols are multi-component with the structural materials dominant in mass; - the retention is low in the RCS pipes but aerosol deposition on containment walls is significant; - the containment sump chemistry is marked by aerosol material dissolution and the resulting iodine trapping by silver. Those results are described in some detail in the following paper. (author)

  11. Fuel and fission product behaviour in early phases of a severe accident. Part I: Experimental results of the PHEBUS FPT2 test

    Energy Technology Data Exchange (ETDEWEB)

    Barrachin, M., E-mail: marc.barrachin@irsn.fr [Institut de Radioprotection et de Sûreté Nucléaire, B.P. 3, 13115 Saint Paul-lez-Durance Cedex (France); Gavillet, D. [Paul Scherrer Institute, Würenlingen and Villigen, CH-5232 Villigen PSI (Switzerland); Dubourg, R. [Institut de Radioprotection et de Sûreté Nucléaire, B.P. 3, 13115 Saint Paul-lez-Durance Cedex (France); De Bremaecker, A. [Institute for Nuclear Materials Sciences, SCK-CEN, Boeretang 200, B-2400 Mol (Belgium)

    2014-10-15

    One objective of the FPT2 test of the PHEBUS FP Program was to study the degradation of an irradiated UO{sub 2} fuel test section and the fission product behaviour under conditions of low steam flow. The results of the post-irradiation examinations (PIE) at the upper levels (823 and 900 mm) of the 1-m long test section are presented in this paper. Material interactions leading to local corium formation were identified: firstly between fuel and Zircaloy-4 cladding, notably at 823 mm, where the cladding melting temperature was reached, and secondly between fuel and stainless steel oxides. Regarding fission products, molybdenum left so-called metallic precipitates mainly composed of ruthenium. Xenon and caesium behave similarly whereas barium and molybdenum often seems to be associated in precipitates.

  12. GGA+U study of uranium mononitride: A comparison of the U-ramping and occupation matrix schemes and incorporation energies of fission products

    Science.gov (United States)

    Claisse, Antoine; Klipfel, Marco; Lindbom, Niclas; Freyss, Michel; Olsson, Pär

    2016-09-01

    Uranium mononitride is studied in the DFT + U framework. Its ground state is investigated and a study of the incorporation of diverse fission products in the crystal is conducted. The U-ramping and occupation matrix control (OMC) schemes are used to eliminate metastable states. Beyond a certain amount of introduced correlation, the OMC scheme starts to find a lower total energy. The OMC scheme is chosen for the second part of this study. Furthermore, the influence of the magnetic ordering is studied using the U-ramping method, showing that antiferromagnetic order is the most stable one when the U parameter is larger than 1.75 eV. The effect on the density of states is investigated and elastic constants are provided for comparison with other methods and experiments. The incorporation energies of fission products in different defect configurations are calculated and these energies are corrected to take into account the limited size of the supercell.

  13. Correlation between Asian Dust and Specific Radioactivities of Fission Products Included in Airborne Samples in Tokushima, Shikoku Island, Japan, Due to the Fukushima Nuclear Accident

    Energy Technology Data Exchange (ETDEWEB)

    Sakama, M., E-mail: minorusakama@tokushima-u.ac.jp [Department of Radiological Science, Division of Biomedical Information Sciences, Institute of Health Biosciences, The University of Tokushima, Tokushima 770-8509 (Japan); Nagano, Y. [Department of Radiological Science, Division of Biomedical Information Sciences, Institute of Health Biosciences, The University of Tokushima, Tokushima 770-8509 (Japan); Kitade, T. [Department of Laboratory, M and S Instruments Inc., Osaka 532-0005 (Japan); Shikino, O. [Department of Inorganic Analysis, PerkinElmer Japan Co. Ltd., Yokohama 240-0005 (Japan); Nakayama, S. [Department of Nuclear Science, Institute of Socio-Arts and Sciences, The University of Tokushima, Tokushima 770-8502 (Japan)

    2014-06-15

    Radioactive fission product {sup 131}I released from the Fukushima Daiichi Nuclear Power Plants (FD-NPP) was first detected on March 23, 2011 in an airborne aerosol sample collected at Tokushima, Shikoku Island, located in western Japan. Two other radioactive fission products, {sup 134}Cs and {sup 137}Cs were also observed in a sample collected from April 2 to 4, 2011. The maximum specific radioactivities observed in this work were about 2.5 to 3.5 mBq×m{sup -3} in a airborne aerosol sample collected on April 6. During the course of the continuous monitoring, we also made our first observation of seasonal Asian Dust and those fission products associated with the FDNPP accident concurrently from May 2 to 5, 2011. We found that the specific radioactivities of {sup 134}Cs and {sup 137}Cs decreased drastically only during the period of Asian Dust. And also, it was found that this trend was very similar to the atmospheric elemental concentration (ng×m{sup -3}) variation of stable cesium ({sup 133}Cs) quantified by elemental analyses using our developed ICP-DRC-MS instrument.

  14. Coexpression of redox partners increases the hydrocortisone (cortisol) production efficiency in CYP11B1 expressing fission yeast Schizosaccharomyces pombe.

    Science.gov (United States)

    Hakki, Tarek; Zearo, Silvia; Drăgan, Călin-Aurel; Bureik, Matthias; Bernhardt, Rita

    2008-02-01

    Cytochromes P450 play a vital role in the steroid biosynthesis pathway of the adrenal gland. An example of an essential P450 cytochrome is the steroid 11beta-hydroxylase CYP11B1, which catalyses the conversion of 11-deoxycorticol to hydrocortisone. However, despite its high biotechnological potential, this enzyme has so far been unsuccessfully employed in present-day biotechnology due to a poor expression yield and inherent protein instability. In this study, CYP11B1 was biotransformed into various strains of the yeast Schizosaccharomyces pombe, all of which also expressed the electron transfer proteins adrenodoxin and/or adrenodoxin reductase - central components of the mitochondrial P450 system - in order to maximise hydrocortisone production efficiency in our proposed model system. Site-directed mutagenesis of CYP11B1 at positions 52 and 78 was performed in order to evaluate the impact of altering the amino acids at these sites. It was found that the presence of an isoleucine at position 78 conferred the highest 11beta-hydroxylation activity of CYP11B1. Coexpression of adrenodoxin and adrenodoxin reductase appeared to further increase the 11beta-hydroxylase activity of the enzyme (3.4 fold). Adrenodoxin mutants which were found to significantly enhance enzyme efficiency in other cytochromes in previous studies were also tested in our system. It was found that, in this case, the wild type adrenodoxin was more efficient. The new fission yeast strain TH75 coexpressing the wild type Adx and AdR displays high hydrocortisone production efficiency at an average of 1mM hydrocortisone over a period of 72h, the highest value published to date for this biotransformation. Finally, our research shows that pTH2 is an ideal plasmid for the coexpression of the mitochondrial electron transfer counterparts, adrenodoxin and adrenodoxin reductase, in Schizosaccharomyces pombe, and so could serve as a convenient tool for future biotechnological applications.

  15. Determination of Fission Products in Irradiated Fuel by X-Ray Fluorescence

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Als-Nielsen, Jens Aage; Andersen, Niels Hessel

    X-ray fluorescence i s a well e s t a b l i s h e d analytical tool for measuring elemental composition of fairly large (~ 5 cm2) "cold" samples. A version of t h i s technique has been developed for a n a l y s i s of radial d i s t r i b u t i o n of f i s s i o n products Xe, Cs and Ba in irra...

  16. Changes in Densities of Basic Constituents during CRMB Production

    Directory of Open Access Journals (Sweden)

    Naeem Aziz Memon

    2016-02-01

    Full Text Available Along with other polymers, Crumb Rubber (CR obtained from scrap tyres has also resulted in enhanced performance of the virgin binder to meet the increased traffic density. However, the nature of reaction between the primary components has been reported to be different compared to the other polymer modification resulting in an heterogeneous blend of primary components. Despite the enhanced physical and performance characteristics of CRMB such as improved rutting and fatigue resistance, the product is still not widely accepted; the reason being inadequate and inconsistent observations from different researchers and agencies around the world. This has also led to a gap, where industry and the research community are still trying to understand and control the reaction mechanism between CR and bitumen to obtain consistent results. To understand the reaction mechanism, a total of 27 CRMB blends with different material combinations were prepared in the laboratory. To examine the changes, samples were collected after different intervals of blending and further subjected to laboratory observations for volumetric changes. The collected samples were then put through the separation processes to recover binder residue and swollen CR for further laboratory analysis. Results demonstrated that the aging of bitumen make it harder due to oxidation. Equally CRMB production also contributes to the hardening of base bitumen due to the diffusion of lighter fractions of bitumen into the CR particles. This resulted in changes in volumetric of the blend, bitumen and CR. The main factors responsible for these changes were; proportion of the primary components, CR size, base bitumen grade and volatilisation during production. As a result, a maximum increase of up to 0.42% and 3.9% was observed in the densities of CRMB and bitumen residue respectively. However, a significant reduction of 19% in the densities of the CR phase was observed.

  17. (d,p)-transfer induced fission of heavy radioactive beams

    CERN Document Server

    Veselsky, Martin

    2012-01-01

    (d,p)-transfer induced fission is proposed as a tool to study low energy fission of exotic heavy nuclei. Primary goal is to directly determine the fission barrier height of proton-rich fissile nuclei, preferably using the radio-active beams of isotopes of odd elements, and thus confirm or exclude the low values of fission barrier heights, typically extracted using statistical calculations in the compound nucleus reactions at higher excitation energies. Calculated fission cross sections in transfer reactions of the radioactive beams show sufficient sensitivity to fission barrier height. In the probable case that fission rates will be high enough, mass asymmetry of fission fragments can be determined. Results will be relevant for nuclear astrophysics and for production of super-heavy nuclei. Transfer induced fission offers a possibility for systematic study the low energy fission of heavy exotic nuclei at the ISOLDE.

  18. Estimation of the radiation strength, dose equivalent and mean gamma-ray energy form p+ sup 2 sup 3 sup 8 U fission products

    CERN Document Server

    Kawakami, H

    2003-01-01

    On 100 isobars from 72 to 171 mass number, the radiation strength, dose equivalent and mean gamma-ray energy from p+ sup 2 sup 3 sup 8 U fission products at Tandem accelerator facility were estimated on the basis of data of proton induced fission mass yield by T. Tsukada. In order to control radiation, the decay curves of radiation of each mass after irradiation were estimated and illustrated. These calculation results showed 1) the peak of p+ sup 2 sup 3 sup 8 U fission products is 101 and 133 mass number. 2) gamma-ray strength of target ion source immediately after irradiation is 3.12x10 sup 1 sup 1 (Radiation/s) when it repeated 4 cycles of UC sub 2 (2.6 g/cm sup 2) target radiated by 30 MeV and 3 mu A proton for 5 days and then cooled for 2 days. It decreased to 3.85x10 sup 1 sup 0 and 6.7x10 sup 9 (Radiation/s) after one day and two weeks cooling, respectively. 3) Total dose equivalent is 3.8x10 sup 4 (mu S/h) at 1 m distance without shield. 4) There are no problems on control the following isobars, beca...

  19. Penning trap mass measurements and laser spectroscopy on neutron-rich fission products extracted from the research reactor TRIGA-Mainz

    Energy Technology Data Exchange (ETDEWEB)

    Eibach, Martin; Ketelaer, Jens; Ketter, Jochen; Knuth, Konstantin [Institut fuer Physik, Universitaet Mainz (Germany); Blaum, Klaus; Nagy, Szilard [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Eberhardt, Klaus; Noertershaeuser, Wilfried [Institut fuer Kernchemie, Universitaet Mainz (Germany); Herfurth, Frank [GSI, Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Smorra, Christian [Physikalisches Institut, Universitaet Heidelberg (Germany); Institut fuer Kernchemie, Universitaet Mainz (Germany)

    2009-07-01

    TRIGA-SPEC is a setup for Penning trap mass spectrometry and collinear laser spectroscopy on short-lived neutron-rich nuclides located at the research reactor TRIGA-Mainz. It is dedicated to the determination of nuclear ground-state properties like masses and charge-radii. The nuclides are produced by neutron-induced fission of an actinide target located in a target chamber near the reactor core. It is required to extract the nuclides fast and with high efficiency from the target chamber in order to make precision experiments on short-living species with half-lives in the order of 1s. To this end, they are flushed out with a helium gas jet containing carbon aerosols and transported through a skimmer region to an ECR ion source. The characterisation of the carbon aerosol generator and the verification of transported fission products are presented.

  20. Ideological Fission

    DEFF Research Database (Denmark)

    Christiansen, Steen Ledet

    ; it is a materialisation of an ideological fission which attempts to excise certain ideological constructions, yet paradoxically casting them in a form that is recognizable and familiar. The monstrous metonomy which is used shows us glimpses of a horrid being, intended to vilify the attack on New York City. However......, it is a being which is reminiscent of earlier monsters - from Godzilla to The Blob. It is evident that the Cloverfield monster is a paradoxical construction which attempts to articulate fear and loathing about terrorism, but ends up trapped in an ideological dead-end maze, unable to do anything other than...

  1. Study of the short-lived fission products. Separation of iodine and xenon fission radionuclides; Estudio de los productos de fision de periodo corto. Separacion de los radionuclidos de fision del yodo y del xenon

    Energy Technology Data Exchange (ETDEWEB)

    Barrachina, M.; Villar, M. A.

    1965-07-01

    The separation by distillation in a sulfuric acid or phosphoric acid-hydrogen peroxide medium of the iodine isotopes (8 day iodine-131, 2,3 hour iodine-132 21 hour iodine-133, 53 minute iodine-134 and 6,7 hour iodine-135) present in a uranium sample after different irradiation and cooling times is here described. It is also reported the use of active charcoal columns for the retention of xenon isotopes (5,27 days xenon-133 and 9,2 hours xenon-135) either released during the dissolution of the uranium irradiated samples or generated along the fission isobaric chains in the solutions of distillated iodine. In both cases the radiochemical purity of the separated products is established by gamma spectrometry. (Author) 15 refs.

  2. Beta decay of the fission product 125Sb and a new complete evaluation of absolute gamma ray transition intensities

    Science.gov (United States)

    Rajput, M. U.; Ali, N.; Hussain, S.; Mujahid, S. A.; MacMahon, D.

    2012-04-01

    The radionuclide 125Sb is a long-lived fission product, which decays to 125Te by negative beta emission with a half-life of 1008 day. The beta decay is followed by the emission of several gamma radiations, ranging from low to medium energy, that can suitably be used for high-resolution detector calibrations, decay heat calculations and in many other applications. In this work, the beta decay of 125Sb has been studied in detail. The complete published experimental data of relative gamma ray intensities in the beta decay of the radionuclide 125Sb has been compiled. The consistency analysis was performed and discrepancies found at several gamma ray energies. Evaluation of the discrepant data was carried out using Normalized Residual and RAJEVAL methods. The decay scheme balance was carried out using beta branching ratios, internal conversion coefficients, populating and depopulating gamma transitions to 125Te levels. The work has resulted in the consistent conversion factor equal to 29.59(13) %, and determined a new evaluated set of the absolute gamma ray emission probabilities. The work has also shown 22.99% of the delayed intensity fraction as outgoing from the 58 d isomeric 144 keV energy level and 77.01% of the prompt intensity fraction reaching to the ground state from the other excited states. The results are discussed and compared with previous evaluations. The present work includes additional experimental data sets which were not included in the previous evaluations. A new set of recommended relative and absolute gamma ray emission probabilities is presented.

  3. Development a recovery method of {sup 13I} from the {sup 23}'5U fission products

    Energy Technology Data Exchange (ETDEWEB)

    Bignardi, Aline M.T.; Osso Junior, Joao Alberto, E-mail: alinebignardi@yahoo.com.br, E-mail: jaosso@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    {sup 13I} is a iodine radioisotope widely used in nuclear medicine that can be used either for diagnostic or for treatment due to its physical decay by β- and its high emission of rays-γ. It is produced at IPEN through the irradiation of TeO{sub 2} targets in the IEA-R1 nuclear reactor. There is also the possibility produced it by the fission of {sup 235}U. The aim of this work is to develop a recovery method of {sup 13I} in the production process of {sup 99}Mo through the route of acid dissolution of {sup 235}U targets, with the quality to be used in Nuclear Medicine. {sup 13I} finds itself in two stages of the process, either in the gaseous produced in the acid dissolution of metallic U targets and the smallest part in solution. In this work was studied the recovery of {sup 131} in these two stages. Several materials were used for the capture and recovery of {sup 13I} at the two phases of the process. Anionic cartridges, Ag cartridges, anion exchange resin, activated charcoal columns and AgI precipitation were tested. Solutions with {sup 13}'1I in 0.1 mol.L{sup -1} NaOH were percolated through the materials and the eluted solutions were analyzed in a dose calibrator. Among all the tests that were executed, at first, the anion exchange resin and AgI precipitation have showed the best retention result (100%). The results of elution have varied according to the material, the activated charcoal presented a elution yield between 70% and 82% At first, it is possible to conclude that anion exchange resin and AgI precipitation show better results for {sup 13I} retention and the column and activated charcoal have a great potential for the elution of {sup 131} in the right chemical state. (author)

  4. Some aspects of fission and quasifission processes

    Indian Academy of Sciences (India)

    B B Back

    2015-08-01

    The discovery of nuclear fission in 1938–1939 had a profound influence on the field of nuclear physics and it brought this branch of physics into the forefront as it was recognized for having the potential for its seminal influence on modern society. Although many of the basic features of actinide fission were described in a ground-breaking paper by Bohr and Wheeler only six months after the discovery, the fission process is very complex and it has been a challenge for both experimentalists and theorists to achieve a complete and satisfactory understanding of this phenomenon. Many aspects of nuclear physics are involved in fission and it continues to be a subject of intense study even three quarters of a century after its discovery. In this talk, I will review an incomplete subset of the major milestones in fission research, and briefly discuss some of the topics that I have been involved in during my career. These include studies of vibrational resonances and fission isomers that are caused by the second minimum in the fission barrier in actinide nuclei, studies of heavy-ion-induced fission in terms of the angular distributions and the mass–angle correlations of fission fragments. Some of these studies provided evidence for the importance of the quasifission process and the attendant suppression of the complete fusion process. Finally, some of the circumstances around the establishment of large-scale nuclear research in India will be discussed.

  5. Measurement of isotopic cross sections of the fission fragments produced in 500 AMeV {sup 208}Pb + p reaction; Etude de la production des fragments de fission issus de la reaction {sup 208}Pb + p a 500 AMeV

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Dominguez, B

    2003-03-01

    The aim of this work is the study of the fission fragments produced in the spallation reaction {sup 208}Pb + p at 500 AMeV. The fission fragments from Z=23 up to Z=59 have been detected and identified by using the inverse kinematics technique with the high-resolution spectrometer FRS. The production cross sections and the recoil velocities of 430 nuclei have been measured. The measured data have been compared with previous data. The isotopic distributions show a high precision. However, the absolute value of the fission cross section is higher than expected. From the experimental data the characteristics of the average fissioning system have been reconstructed (Z{sub fis}, A{sub fis}, E*{sub fis}). In addition, the number of post-fission neutrons emitted from the fission fragments, v{sub post}, has been determined by using a new method. The experimental data have been compared to the two-steps models describing the spallation reaction. The impact of the model parameters on the observables has been analysed and the reasons Leading to the observed differences between the codes are also presented. This analyse shows a good agreement with the INCL4+ABLA code. (author)

  6. Mass Distribution Measurement of 252Cf Spontaneous Fission

    Institute of Scientific and Technical Information of China (English)

    LIU; Shi-long; YANG; Yi; ZHANG; Chun-li; HAN; Hong-yin

    2015-01-01

    The E-v method of measuring the kinetic energy(E)and velocity(v)of outgoing fission products has been utilized,with the goal of measuring the mass resolution better than 1atomic mass units(amu),and could identify every mass for light fission products of unsymmetrical fission.This work measured mass yield distribution

  7. Fission product separations testing

    Energy Technology Data Exchange (ETDEWEB)

    Bostick, D.A.; DePaoli, S.M. [Oak Ridge National Lab., TN (United States)

    1997-10-01

    The initial goal of this task is to adequately understand the treatment needs of the end user in treating contaminated wastewater. These needs are then incorporated into the evaluation of new treatment technologies for wastewater treatment. Pertinent information is than supplied to the end user so that they can select a preferred process to meet their waste treatment needs. New sorbent materials, ion-exchange materials, or other processes of interest to DOE`s Office of Environmental Restoration (EM-40) will be evaluated initially for the removal of {sup 90}Sr and {sup 137}Cs from groundwater and process wastewater. Laboratory studies will strive to obtain a quantitative understanding of the behavior of these new materials and to evaluate their sorption efficiency in reference to a standard benchmark treatment technique. Testing of the new materials will begin by conducting scoping tests where new treatment materials are compared with standard, commercially available materials in batch shaker tests. Experimental data for the most promising sorbents will then be fit to an equilibrium model so that nuclide sorption can be predicted for variable wastewater composition. Additional testing with actual wastewater will be conducted with two or three of the most effective treatment methods. Once batch testing of a treatment method is completed, dynamic column tests will be performed to validate the equilibrium sorption model and to obtain the defining column operating parameters for scaling up the technology.

  8. Radiochemical studies on nuclear fission at Trombay

    Indian Academy of Sciences (India)

    Asok Goswami

    2015-08-01

    Since the discovery of nuclear fission in the year 1939, both physical and radiochemical techniques have been adopted for the study of various aspects of the phenomenon. Due to the ability to separate individual elements from a complex reaction mixture with a high degree of sensitivity and selectivity, a chemist plays a significant role in the measurements of mass, charge, kinetic energy, angular momentum and angular distribution of fission products in various fissioning systems. At Trombay, a small group of radiochemists initiated the work on radiochemical studies of mass distribution in the early sixties. Since then, radiochemical investigations on various fission observables have been carried out at Trombay in , , and heavy-ion-induced fissions. An attempt has been made to highlight the important findings of such studies in this paper, with an emphasis on medium energy and heavy-ion-induced fission.

  9. The production of {sup 238-242}Pu(n,γ){sup 239-243}Pu fissionable fluids in a fusion-fission hybrid reactor

    Energy Technology Data Exchange (ETDEWEB)

    Guenay, Mehtap [Inoenue Univ., Malatya (Turkey). Physics Dept.

    2014-03-15

    In this study, the effect of spent fuel grade plutonium content on {sup 239-243}Pu was investigated in a designed hybrid reactor system. In this system, the fluids were composed of a molten salt, heavy metal mixture with increased mole fractions 99-95 % Li{sub 20}Sn{sub 80}-1-5 % SFG-Pu, 99-95 % Li{sub 20}Sn{sub 80}-1-5 % SFG-PuF{sub 4}, 99-95 % Li{sub 20}Sn{sub 80}-1-5 % SFG-PuO{sub 2}. Beryllium (Be) is a neutron multiplier by (n,2n) reactions. Thence, a Be zone of 3 cm thickness was used in order to contribute to fissile fuel breeding between the liquid first wall and a 9Cr2WVTa ferritic steel blanket which is used as structural material. The production of {sup 238-242}Pu(n,γ){sup 239-243}Pu was calculated in liquid first wall, blanket and shielding zones. Three-dimensional nucleonic calculations were performed by using the most recent version MCNPX-2.7.0 Monte Carlo code and nuclear data library ENDF/B-VII.0. (orig.)

  10. Measurements of yields of fission products in the reaction of {sup 238}U with high-energy p, d and n beams

    Energy Technology Data Exchange (ETDEWEB)

    Nolen, J.A.; Ahmad, I.; Back, B.B. [and others

    1995-08-01

    An experiment was performed at the Michigan State University cyclotron to determine the yields of neutron-rich fission products in the reaction of {sup 238}U with 100-MeV neutrons, 200-MeV deuterons and 200-MeV protons. Several 1-mm-thick {sup 238}U foils were irradiated for 100-second intervals sequentially for each configuration and the ten spectra were added for higher statistics. The three successive spectra, each for a 40 s period, were accumulated for each sample. Ten foils were irradiated. Successive spectra allowed us to determine approximate half-lives of the gamma peaks. Several arrangements, which were similar to the setup we plan to use in our radioactive beam proposal, were used for the production of fission products. For the high-energy neutron irradiation, U foils were placed after a 5-inch-long, 1-inch-diameter Be cylinder which stopped the 200-MeV deuteron beam generating 100-MeV neutrons. Arrangements for deuteron irradiation included direct irradiation of U foils, placing U foils after different lengths of (0.5 inch, 1.0 inch and 1.5 inch) 2-inch diameter U cylinder. Since the deuteron range in uranium is 17 mm, some of the irradiations were due to the secondary neutrons from the deuteron-induced fission of U. Similar arrangements were also used for the 200-MeV proton irradiation of the {sup 238}U foils. In all cases, several neutron-rich fission products were identified and their yields determined. In particular, we were able to observe Sn in all the runs and determine its yield. The data show that with our proposed radioactive device we will be able to produce more than 10{sup 12} {sup 132}Sn atoms per second in the target. Assuming an overall efficiency of 1 %, we will be able to deliver one particle nanoampere of {sup 132}Sn beam at a target location. Detailed analysis of the {gamma}-ray spectra is in progress.

  11. Production of neutron-rich copper isotopes in 30-MeV proton-induced fission of sup 2 sup 3 sup 8 U

    CERN Document Server

    Kruglov, K; Bruyneel, B; Dean, S S; Franchoo, S; Huyse, M; Kudryavtsev, Y; Müller, W F; Prasad, N V S; Raabe, R; Reusen, I; Schmidt, K H; Van De Vel, K; Van Duppen, P; Van Roosbroeck, J; Weissman, L

    2002-01-01

    The neutron-rich isotopes sup 7 sup 0 sup - sup 7 sup 6 Cu have been produced in 30-MeV proton-induced fission of sup 2 sup 3 sup 8 U using the Ion Guide Laser Ion Source (IGLIS) at LISOL. The production rates of the copper isotopes, and of the nickel and cobalt isotopes that were measured earlier, are compared to cross section calculations. Based on these new results an estimate for the cross section of sup 7 sup 8 Ni is given.

  12. Effect of spray system on fission product distribution in containment during a severe accident in a two-loop pressurized water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Dehjourian, Mehdi; Rahgoshay, Mohammad; Jahanfamia, Gholamreza [Dept. of Nuclear Engineering, Science and Research Branch, Islamic Azad University of Tehran, Tehran (Iran, Islamic Republic of); Sayareh, Reza [Faculty of Electrical and Computer Engineering, Kerman Graduate University of Technology, Kerman (Iran, Islamic Republic of); Shirani, Saied [Faculty of Engineering, Shahid Beheshti University, Tehran (Iran, Islamic Republic of)

    2016-08-15

    The containment response during the first 24 hours of a low-pressure severe accident scenario in a nuclear power plant with a two-loop Westinghouse-type pressurized water reactor was simulated with the CONTAIN 2.0 computer code. The accident considered in this study is a large-break loss-of-coolant accident, which is not successfully mitigated by the action of safety systems. The analysis includes pressure and temperature responses, as well as investigation into the influence of spray on the retention of fission products and the prevention of hydrogen combustion in the containment.

  13. Study of the Effect of (U0.8Pu0.2O2 Uranium–Plutonium Mixed Fuel Fission Products on a Living Organism

    Directory of Open Access Journals (Sweden)

    Ayagoz Baimukhanova

    2016-08-01

    Full Text Available The article describes the results of experiments conducted on pigs to determine the effect of plutonium, which is the most radiotoxic and highly active element in the range of mixed fuel (U0.8Pu0.2O2 fission products, on living organisms. The results will allow empirical prediction of the emergency plutonium radiation dose for various organs and tissues of humans in case of an accident in a reactor running on mixed fuel (U0.8Pu0.2O2.

  14. Effect of Spray System on Fission Product Distribution in Containment During a Severe Accident in a Two-Loop Pressurized Water Reactor

    Directory of Open Access Journals (Sweden)

    Mehdi Dehjourian

    2016-08-01

    Full Text Available The containment response during the first 24 hours of a low-pressure severe accident scenario in a nuclear power plant with a two-loop Westinghouse-type pressurized water reactor was simulated with the CONTAIN 2.0 computer code. The accident considered in this study is a large-break loss-of-coolant accident, which is not successfully mitigated by the action of safety systems. The analysis includes pressure and temperature responses, as well as investigation into the influence of spray on the retention of fission products and the prevention of hydrogen combustion in the containment.

  15. Fuel and fission product behaviour in early phases of a severe accident. Part II: Interpretation of the experimental results of the PHEBUS FPT2 test

    Science.gov (United States)

    Dubourg, R.; Barrachin, M.; Ducher, R.; Gavillet, D.; De Bremaecker, A.

    2014-10-01

    One objective of the FPT2 test of the PHEBUS FP Program was to study the degradation of an irradiated UO2 fuel bundle and the fission product behaviour under conditions of low steam flow. The results of the post-irradiation examinations (PIE) at the upper levels (823 mm and 900 mm) of the test section previously reported are interpreted in the present paper. Solid state interactions between fuel and cladding have been compared with the characteristics of interaction identified in the previous separate-effect tests. Corium resulting from the interaction between fuel and cladding was formed. The uranium concentration in the corium is compared to analytical tests and a scenario for the corium formation is proposed. The analysis showed that, despite the rather low fuel burn up, the conditions of temperature and oxygen potential reached during the starvation phase are able to give an early very significant release fraction of caesium. A significant part (but not all) of the molybdenum was segregated at grain boundaries and trapped in metallic inclusions from which they were totally removed in the final part of the experiment. During the steam starvation phase, the conditions of oxygen potential were favourable for the formation of simple Ba and BaO chemical forms but the temperature was too low to provoke their volatility. This is one important difference with out-of-pile experiments such as VERCORS for which only a combination of high temperature and low oxygen potential induced a significant barium release. Finally another significant difference with analytical out-of-pile experiments comes from the formation of foamy zones due to the fission gas presence in FPT2-type experiments which give an additional possibility for the formation of stable fission product compounds.

  16. Fuel and fission product behaviour in early phases of a severe accident. Part II: Interpretation of the experimental results of the PHEBUS FPT2 test

    Energy Technology Data Exchange (ETDEWEB)

    Dubourg, R. [Institut de Radioprotection et de Sûreté Nucléaire, B.P. 3, 13115 Saint Paul-lez-Durance Cedex (France); Barrachin, M., E-mail: marc.barrachin@irsn.fr [Institut de Radioprotection et de Sûreté Nucléaire, B.P. 3, 13115 Saint Paul-lez-Durance Cedex (France); Ducher, R. [Institut de Radioprotection et de Sûreté Nucléaire, B.P. 3, 13115 Saint Paul-lez-Durance Cedex (France); Gavillet, D. [Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland); De Bremaecker, A. [Institute for Nuclear Materials Sciences, SCK-CEN, Boeretang 200, B-2400 Mol (Belgium)

    2014-10-15

    One objective of the FPT2 test of the PHEBUS FP Program was to study the degradation of an irradiated UO{sub 2} fuel bundle and the fission product behaviour under conditions of low steam flow. The results of the post-irradiation examinations (PIE) at the upper levels (823 mm and 900 mm) of the test section previously reported are interpreted in the present paper. Solid state interactions between fuel and cladding have been compared with the characteristics of interaction identified in the previous separate-effect tests. Corium resulting from the interaction between fuel and cladding was formed. The uranium concentration in the corium is compared to analytical tests and a scenario for the corium formation is proposed. The analysis showed that, despite the rather low fuel burn up, the conditions of temperature and oxygen potential reached during the starvation phase are able to give an early very significant release fraction of caesium. A significant part (but not all) of the molybdenum was segregated at grain boundaries and trapped in metallic inclusions from which they were totally removed in the final part of the experiment. During the steam starvation phase, the conditions of oxygen potential were favourable for the formation of simple Ba and BaO chemical forms but the temperature was too low to provoke their volatility. This is one important difference with out-of-pile experiments such as VERCORS for which only a combination of high temperature and low oxygen potential induced a significant barium release. Finally another significant difference with analytical out-of-pile experiments comes from the formation of foamy zones due to the fission gas presence in FPT2-type experiments which give an additional possibility for the formation of stable fission product compounds.

  17. Fission cross section measurements for minor actinides

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-03-01

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

  18. Benz[a]anthracene biotransformation and production of ring fission products by Sphingobium sp. strain KK22.

    Science.gov (United States)

    Kunihiro, Marie; Ozeki, Yasuhiro; Nogi, Yuichi; Hamamura, Natsuko; Kanaly, Robert A

    2013-07-01

    A soil bacterium, designated strain KK22, was isolated from a phenanthrene enrichment culture of a bacterial consortium that grew on diesel fuel, and it was found to biotransform the persistent environmental pollutant and high-molecular-weight polycyclic aromatic hydrocarbon (PAH) benz[a]anthracene. Nearly complete sequencing of the 16S rRNA gene of strain KK22 and phylogenetic analysis revealed that this organism is a new member of the genus Sphingobium. An 8-day time course study that consisted of whole-culture extractions followed by high-performance liquid chromatography (HPLC) analyses with fluorescence detection showed that 80 to 90% biodegradation of 2.5 mg liter(-1) benz[a]anthracene had occurred. Biodegradation assays where benz[a]anthracene was supplied in crystalline form (100 mg liter(-1)) confirmed biodegradation and showed that strain KK22 cells precultured on glucose were equally capable of benz[a]anthracene biotransformation when precultured on glucose plus phenanthrene. Analyses of organic extracts from benz[a]anthracene biodegradation by liquid chromatography negative electrospray ionization tandem mass spectrometry [LC/ESI(-)-MS/MS] revealed 10 products, including two o-hydroxypolyaromatic acids and two hydroxy-naphthoic acids. 1-Hydroxy-2- and 2-hydroxy-3-naphthoic acids were unambiguously identified, and this indicated that oxidation of the benz[a]anthracene molecule occurred via both the linear kata and angular kata ends of the molecule. Other two- and single-aromatic-ring metabolites were also documented, including 3-(2-carboxyvinyl)naphthalene-2-carboxylic acid and salicylic acid, and the proposed pathways for benz[a]anthracene biotransformation by a bacterium were extended.

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

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, C

    1999-09-01

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

  20. Fission-product behaviour in irradiated TRISO-coated particles: Results of the HFR-EU1bis experiment and their interpretation

    Energy Technology Data Exchange (ETDEWEB)

    Barrachin, M., E-mail: marc.barrachin@irsn.fr [Institut de Radioprotection et de Surete Nucleaire (IRSN), BP3, 13115 Saint Paul Lez Durance (France); Dubourg, R. [Institut de Radioprotection et de Surete Nucleaire (IRSN), BP3, 13115 Saint Paul Lez Durance (France); Groot, S. de [Nuclear Research and Consultancy Group (NRG), P.O. Box 25, 1755 ZG Petten (Netherlands); Kissane, M.P. [Institut de Radioprotection et de Surete Nucleaire (IRSN), BP3, 13115 Saint Paul Lez Durance (France); Bakker, K. [Nuclear Research and Consultancy Group (NRG), P.O. Box 25, 1755 ZG Petten (Netherlands)

    2011-08-01

    Highlights: > The microstructure and FPs in UO{sub 2} TRISO particles (10% FIMA, 1573 K) were studied. > Very large porosities (>10 {mu}m) were observed in the high temperature particles. > Significant Xe and Cs releases from the kernel were observed. > Mo and Ru are mainly present in the metallic precipitates in the kernel. - Abstract: It is important to understand fission-product (FP) and kernel micro-structure evolution in TRISO-coated fuel particles. FP behaviour, while central to severe-accident evaluation, impacts: evolution of the kernel oxygen potential governing in turn carbon oxidation (amoeba effect and pressurization); particle pressurization through fission-gas release from the kernel; and coating mechanical resistance via reaction with some FPs (Pd, Cs, Sr). The HFR-Eu1bis experiment irradiated five HTR fuel pebbles containing TRISO-coated UO{sub 2} particles and went beyond current HTR specifications (e.g., central temperature of 1523 K). This study presents ceramographic and EPMA examinations of irradiated urania kernels and coatings. Significant evolutions of the kernel (grain structure, porosity, metallic-inclusion size, intergranular bubbles) as a function of temperature are shown. Results concerning FP migration are presented, e.g., significant xenon, caesium and palladium release from the kernel, molybdenum and ruthenium mainly present in metallic precipitates. The observed FP and micro-structural evolutions are interpreted and explanations proposed. The effect of high flux rate and high temperature on fission-gas behaviour, grain-size evolution and kernel swelling is discussed. Furthermore, Cs, Mo and Zr behaviour is interpreted in connection with oxygen-potential. This paper shows that combining state-of-the-art post-irradiation examination and state-of-the-art modelling fundamentally improves understanding of HTR fuel behaviour.

  1. Los Alamos National Laboratory Fission Basis

    Energy Technology Data Exchange (ETDEWEB)

    Keksis, A.L.; Chadwick, M.B.; Selby, H.D.; Mac Innes, M.R.; Barr, D.W.; Meade, R.A.; Burns, C.J.; Wallstrom, T.C. [Los Alamos National Laboratory, NM 87545 (United States)

    2011-07-01

    This report is an overview of two main publications that provide a comprehensive review of the Los Alamos National Laboratory (LANL) Fission Basis. The first is the experimental paper, {sup F}ission Product Data Measured at Los Alamos for Fission Spectrum and Thermal Neutrons on {sup 239}Pu, {sup 235}U, {sup 238}U, [Selby, H. D., et al., Nucl. Data Sheets, Vol. 111 2010, pp. 2891-2922] and the second is the theoretical paper, Fission Product Yields from Fission Spectrum n+ {sup 239}Pu for ENDF/B-VII.1, [Chadwick, M. B., et al., Nucl. Data Sheets, Vol. 111, 2010, pp. 2923-2964]. One important note is that none of this work would have been possible without the great documentation of the experimental details and results by G.W. Knobeloch, G. Butler, C.I. Browne, B. Erdal, B. Bayhurst, R. Prestwood, V. Armijo, J. Hasty and many others. (authors)

  2. Thorium-uranium fission radiography

    Science.gov (United States)

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

    1976-01-01

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

  3. [Production of data for the pre-natal information system in basic health units].

    Science.gov (United States)

    Lima, Aline Pinto de; Corrêa, Aurea Christina de Paula

    2013-08-01

    The objective of this study was to analyze the process of data production for Information System Prenatal and Birth (SISPRENATAL) in Basic Health Units of Cuiabá, MT, Brazil. This qualitative, exploratory and descriptive study was developed in eight units of Basic Health Coordination, through semi-structured interviews with professionals who worked with SISPRENATAL (nurses, physicians, managers and data entry) and comparative document analysis between system data and the written patient records. Data analysis revealed a lack of definition of the team's participation in the production of data and different modes of completing forms within the system. Professionals' knowledge about many aspects of the formswas divergent, completion of the forms was inadequate, and flaws in the computerized system were identified. Measures such as professional training, the review of the system and its forms are indispensible for the production of reliable information about prenatal care in the municipality.

  4. 48 CFR 252.216-7000 - Economic price adjustment-basic steel, aluminum, brass, bronze, or copper mill products.

    Science.gov (United States)

    2010-10-01

    ...-basic steel, aluminum, brass, bronze, or copper mill products. 252.216-7000 Section 252.216-7000 Federal... adjustment—basic steel, aluminum, brass, bronze, or copper mill products. As prescribed in 216.203-4-70(a... Mill Products (JUL 1997) (a) Definitions. As used in this clause— Established price means a price...

  5. Energy Dependence of Fission Product Yields from 235U, 238U and 239Pu for Incident Neutron Energies Between 0.5 and 14.8 MeV

    Science.gov (United States)

    Gooden, M. E.; Arnold, C. W.; Becker, J. A.; Bhatia, C.; Bhike, M.; Bond, E. M.; Bredeweg, T. A.; Fallin, B.; Fowler, M. M.; Howell, C. R.; Kelley, J. H.; Krishichayan; Macri, R.; Rusev, G.; Ryan, C.; Sheets, S. A.; Stoyer, M. A.; Tonchev, A. P.; Tornow, W.; Vieira, D. J.; Wilhelmy, J. B.

    2016-01-01

    Fission Product Yields (FPY) have historically been one of the most observable features of the fission process. They are known to have strong variations that are dependent on the fissioning species, the excitation energy, and the angular momentum of the compound system. However, consistent and systematic studies of the variation of these FPY with energy have proved challenging. This is caused primarily by the nature of the experiments that have traditionally relied on radiochemical procedures to isolate specific fission products. Although radiochemical procedures exist that can isolate all products, each element presents specific challenges and introduces varying degrees of systematic errors that can make inter-comparison of FPY uncertain. Although of high importance in fields such as nuclear forensics and Stockpile Stewardship, accurate information about the energy dependence of neutron induced FPY are sparse, due primarily to the lack of suitable monoenergetic neutron sources. There is a clear need for improved data, and to address this issue, a collaboration was formed between Los Alamos National Laboratory (LANL), Lawrence Livermore National Laboratory (LLNL) and the Triangle Universities Nuclear Laboratory (TUNL) to measure the energy dependence of FPY for 235U, 238U and 239Pu. The measurements have been performed at TUNL, using a 10 MV Tandem Van de Graaff accelerator to produce monoenergetic neutrons at energies between 0.6 MeV to 14.8 MeV through a variety of reactions. The measurements have utilized a dual-fission chamber, with thin (10-100 μg/cm2) reference foils of similar material to a thick (100-400 mg) activation target held in the center between the chambers. This method allows for the accurate determination of the number of fissions that occurred in the thick target without requiring knowledge of the fission cross section or neutron fluence on target. Following activation, the thick target was removed from the dual-fission chamber and gamma

  6. To fission or not to fission

    CERN Document Server

    Pomorski, Krzysztof; Ivanyuk, Fedir A

    2016-01-01

    The fission-fragments mass-yield of 236U is obtained by an approximate solution of the eigenvalue problem of the collective Hamiltonian that describes the dynamics of the fission process whose degrees of freedom are: the fission (elongation), the neck and the mass-asymmetry mode. The macroscopic-microscopic method is used to evaluate the potential energy surface. The macroscopic energy part is calculated using the liquid drop model and the microscopic corrections are obtained using the Woods-Saxon single-particle levels. The four dimensional modified Cassini ovals shape parametrization is used to describe the shape of the fissioning nucleus. The mass tensor is taken within the cranking-type approximation. The final fragment mass distribution is obtained by weighting the adiabatic density distribution in the collective space with the neck-dependent fission probability. The neck degree of freedom is found to play a significant role in determining that final fragment mass distribution.

  7. Fission products silver, palladium, and cadmium identification in neutron-irradiated SiC TRISO particles using a Cs-Corrected HRTEM

    Science.gov (United States)

    van Rooyen, I. J.; Olivier, E. J.; Neethling, J. H.

    2016-08-01

    Electron microscopy investigations of selected coated particles from the first advanced gas reactor experiment at Idaho National Laboratory provided important information on fission product distribution and chemical composition in the silicon-carbide (SiC) layer. Silver precipitates were nano-sized, and therefore high-resolution transmission electron microscopy (HRTEM) was used to provide more information at the atomic level. Based on gamma-ray analysis, this particle which was irradiated to an average burnup of 19.38% fissions per initial metal atom, may have released as much as 10% of its available Ag-110 m inventory during irradiation. The HRTEM investigation focused on silver, palladium, and cadmium due to interest in silver transport mechanisms and possible correlation with palladium and silver previously found. Palladium, silver, and cadmium were found to co-exist in some of the SiC grain boundaries and triple junctions. This study confirmed palladium both at inter and intragranular sites. Phosphor was identified in SiC grain boundaries and triple points.

  8. Fission dynamics within time-dependent Hartree-Fock: boost-induced fission

    CERN Document Server

    Goddard, P M; Rios, A

    2015-01-01

    Background: Nuclear fission is a complex large-amplitude collective decay mode in heavy nuclei. Microscopic density functional studies of fission have previously concentrated on adiabatic approaches based on constrained static calculations ignoring dynamical excitations of the fissioning nucleus, and the daughter products. Purpose: To explore the ability of dynamic mean-field methods to describe induced fission processes, using quadrupole boosts in the nuclide $^{240}$Pu as an example. Methods: Quadrupole constrained Hartree-Fock calculations are used to create a potential energy surface. An isomeric state and a state beyond the second barrier peak are excited by means of instantaneous as well as temporally extended gauge boosts with quadrupole shapes. The subsequent deexcitation is studied in a time-dependent Hartree-Fock simulation, with emphasis on fissioned final states. The corresponding fission fragment mass numbers are studied. Results: In general, the energy deposited by the quadrupole boost is quickl...

  9. Modeling of fuel performance and fission product release behavior during HTTR normal operation. A comparative study of the FZJ and JAERI modeling approach

    Energy Technology Data Exchange (ETDEWEB)

    Verfondern, Karl [Research Center Juelich (FZJ) (Germany); Sumita, Junya; Ueta, Shohei; Sawa, Kazuhiro [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment

    2001-03-01

    For the prediction of fuel performance and fission product release behavior in the High Temperature Engineering Test Reactor, HTTR of the Japan Atomic Energy Research Institute(JAERI), during its normal operation, calculation tools were applied as have been used at the Research Center Juelich (FZJ) in safety analyses for pebble-bed HTGR designs. Calculations were made assuming the HTTR operation with a nominal operation time of 660 efpd including a 110 efpd period with elevated fuel temperatures. Fuel performance calculations by the PANAMA code with given fuel temperature distribution in the core have shown that the additional failure level of about 5x10{sup -6} is expected which is about twice as much as the as-fabricated through-coatings failure level. Under the extreme safety design conditions, the predicted particle failure fraction in the core increases to about 1x10{sup -3} in maximum. The diffusive release of metallic fission products from the fuel primarily occurs in the core layer with the maximum fuel temperature (layer 3) whereas there is hardly any contribution from layer 1 except for the recoil fraction. Silver most easily escapes the fuel; the predicted release fractions from the fuel compacts are 10% (expected) and 50% (safety design). The figures for strontium (expected: 1.5x10{sup -3}, safety design: 3.1x10{sup -2}) and cesium (5.6x10{sup -4}, 2.9x10{sup -2}) reveal as well a significant fraction to originate already from intact particles. Comparison with the calculation based on JAERI's diffusion model for cesium shows a good agreement for the release behavior from the particles. The differences in the results can be explained mainly by the different diffusion coefficients applied. The release into the coolant can not modelled because of the influence of the gap between compact and graphite sleeve lowering the release by a factor of 3 to 10. For the prediction of performance and fission product release behavior of advanced ZrC TRISO particles

  10. Correlation measurements of fission-fragment properties

    Directory of Open Access Journals (Sweden)

    Oberstedt A.

    2010-10-01

    Full Text Available For the development of future nuclear fission applications and for a responsible handling of nuclear waste the a-priori assessment of the fission-fragments’ heat production and toxicity is a fundamental necessity. The success of an indispensable modelling of the fission process strongly depends on a good understanding of the particular mechanism of scission, the mass fragmentation and partition of excitation energy. Experimental observables are fission-fragment properties like mass- and energy-distributions, and the prompt neutron as well as γ-ray multiplicities and emission spectra. The latter quantities should preferably be known as a function of fragment mass and excitation energy. Those data are highly demanded as published by the OECD-NEA in its high priority data request list. With the construction of the double (v, E spectrometer VERDI we aim at measuring pre- and post-neutron masses directly and simultaneously to avoid prompt neutron corrections. From the simultaneous measurement of pre- and post-neutron fission-fragment data the prompt neutron multiplicity may then be inferred fully correlated with fragment mass yield and total kinetic energy. Using an ultra-fast fission event trigger spectral prompt fission γ-ray measurements may be performed. For that purpose recently developed lanthanum-halide detectors, with excellent timing characteristics, were coupled to the VERDI spectrometer allowing for a very good discrimination of fission γ-rays and prompt neutrons due to their different time-of-flight.

  11. Preliminary treatment of chlorinated streams containing fission products: mechanisms leading to crystalline phases in molten chloride media; Pretraitement pyrochimique de flux charges en produits de fission: mecanismes conduisant a l'obtention de phases cristallines en milieux chlorures fondus

    Energy Technology Data Exchange (ETDEWEB)

    Hudry, D

    2008-10-15

    The world of the nuclear power gets ready for profound modifications so that 'the atom' can aspire in conformance with long-lasting energy: it is what we call the development of generation IV nuclear systems. So, the new pyrochemical separation processes for the spent fuel reprocessing are currently being investigated. Techniques in molten chloride media generate an ultimate flow (with high chlorine content) which cannot be incorporated in conventional glass matrices. This flow is entirely water-soluble and must be conditioned in a chemical form which is compatible with a long-term disposal. This work of thesis consists in studying new ways for the management of the chlorinated streams loaded with fission products (FP). To do it, a strategy of selective FP extraction via the in situ formation of crystalline phases was retained. The possibility of extracting rare earths in the eutectic LiCl-KCl was demonstrated via the development of a new way of synthesis of rare earth phosphates (TRPO{sub 4}). As regards alkaline earths, the conversion of strontium and barium chlorides to the corresponding tungstates or molybdates was studied in different solvents. Mechanisms leading to the crystalline phases in molten chloride media were studied via the coupling of NMR and XRD techniques. First of all, it has been shown that these mechanisms are dependent on the stability of the used precursors. So in the case of the formation of rare earth phosphates the solvent is chemically active. On the other hand, in the case of the formation of alkaline earth tungstates it would seem that the solvent plays the role of structuring agent which can control the ability to react of chlorides. (author)

  12. Fission product removal by containment spray - influence of the distance between the drops on the aerosol collection efficiency; Influence de la densite spatiale des gouttes d'aspersion sur l'efficacite de collecte des produits de fission

    Energy Technology Data Exchange (ETDEWEB)

    Gauchet, N

    2000-07-01

    This work is within the framework of the studies that are conducted at the IPSN concerning the loss of coolant in a nuclear reactor. During this kind of accident, a spray system in the reactor containment induces the scrubbing of fission products in the atmosphere, and allows the decrease of their concentration in the containment. Our objective is to study the influence of the distance between the drops of their aerosol collection efficiency. This is not taken into account in the existing models. We stimulate the various aerosol collection mechanisms with one free falling drop using computational fluid dynamics codes. The mechanisms are: deposition by brownian diffusion, impaction and interception of the particles by the drop, and collection of particles in the presence of steam condensation at the surface of the drop. These phenomena are studied for drops ranging in diameter from 100 to 700 micrometers, falling in a saturated air-steam mixture whose temperature varies between 20 and 140 degrees Celsius, and total pressure varies between 1 and 5 bars. We validate these models with results available in the literature and with experimental results CARAIDAS. Then we apply these models to the case of three aligned drops, which constitutes a case for which the proximity of the drops has a strong influence on the collection of aerosols. While varying the distance between the drop from 5 to 25 drop diameters, we can highlight the modification of the collection efficiency of each mechanism related to the disturbance of the velocity and concentration fields in the vicinity of the drops. We note that the strongest variations of efficiency observed are in the field of impaction, and that the steam condensation at the surface of the drops limits the decrease. (authors)

  13. KUGEL: a thermal, hydraulic, fuel performance, and gaseous fission product release code for pebble bed reactor core analysis

    Energy Technology Data Exchange (ETDEWEB)

    Shamasundar, B.I.; Fehrenbach, M.E.

    1981-05-01

    The KUGEL computer code is designed to perform thermal/hydraulic analysis and coated-fuel particle performance calculations for axisymmetric pebble bed reactor (PBR) cores. This computer code was developed as part of a Department of Energy (DOE)-funded study designed to verify the published core performance data on PBRs. The KUGEL code is designed to interface directly with the 2DB code, a two-dimensional neutron diffusion code, to obtain distributions of thermal power, fission rate, fuel burnup, and fast neutron fluence, which are needed for thermal/hydraulic and fuel performance calculations. The code is variably dimensioned so that problem size can be easily varied. An interpolation routine allows variable mesh size to be used between the 2DB output and the two-dimensional thermal/hydraulic calculations.

  14. Theoretical Description of the Fission Process

    Energy Technology Data Exchange (ETDEWEB)

    Witold Nazarewicz

    2009-10-25

    Advanced theoretical methods and high-performance computers may finally unlock the secrets of nuclear fission, a fundamental nuclear decay that is of great relevance to society. In this work, we studied the phenomenon of spontaneous fission using the symmetry-unrestricted nuclear density functional theory (DFT). Our results show that many observed properties of fissioning nuclei can be explained in terms of pathways in multidimensional collective space corresponding to different geometries of fission products. From the calculated collective potential and collective mass, we estimated spontaneous fission half-lives, and good agreement with experimental data was found. We also predicted a new phenomenon of trimodal spontaneous fission for some transfermium isotopes. Our calculations demonstrate that fission barriers of excited superheavy nuclei vary rapidly with particle number, pointing to the importance of shell effects even at large excitation energies. The results are consistent with recent experiments where superheavy elements were created by bombarding an actinide target with 48-calcium; yet even at high excitation energies, sizable fission barriers remained. Not only does this reveal clues about the conditions for creating new elements, it also provides a wider context for understanding other types of fission. Understanding of the fission process is crucial for many areas of science and technology. Fission governs existence of many transuranium elements, including the predicted long-lived superheavy species. In nuclear astrophysics, fission influences the formation of heavy elements on the final stages of the r-process in a very high neutron density environment. Fission applications are numerous. Improved understanding of the fission process will enable scientists to enhance the safety and reliability of the nation’s nuclear stockpile and nuclear reactors. The deployment of a fleet of safe and efficient advanced reactors, which will also minimize radiotoxic

  15. Chemical states of fission products in irradiated (U 0.3Pu 0.7)C 1+ x fuel at high burn-ups

    Science.gov (United States)

    Agarwal, Renu; Venugopal, V.

    2006-12-01

    The chemical states of fission products have been theoretically determined for the irradiated carbide fuel of Fast Breeder Test Reactor (FBTR) at Kalpakkam, India, at different burn-ups. The SOLGASMIX-PV computer code was used to determine the equilibrium chemical composition of the fuel. The system was assumed to be composed of a gaseous phase at one atmosphere pressure, and various solid phases. The distribution of elements in these phases and their chemical states at different temperatures were calculated as a function of burn-up. The FBTR fuel, (U 0.3Pu 0.7)C 1+ x, was loaded with C/M values in the range, 1.03-1.06. The present calculations indicated that even for the lowest starting C/M of 1.03 in the FBTR fuel, the liquid metal phase of (U, Pu), should not appear at a burn-up as high as 150 GWd/t.

  16. Instant release of fission products in leaching experiments with high burn-up nuclear fuels in the framework of the Euratom project FIRST- Nuclides

    Science.gov (United States)

    Lemmens, K.; González-Robles, E.; Kienzler, B.; Curti, E.; Serrano-Purroy, D.; Sureda, R.; Martínez-Torrents, A.; Roth, O.; Slonszki, E.; Mennecart, T.; Günther-Leopold, I.; Hózer, Z.

    2017-02-01

    The instant release of fission products from high burn-up UO2 fuels and one MOX fuel was investigated by means of leach tests. The samples covered PWR and BWR fuels at average rod burn-up in the range of 45-63 GWd/tHM and included clad fuel segments, fuel segments with opened cladding, fuel fragments and fuel powder. The tests were performed with sodium chloride - bicarbonate solutions under oxidizing conditions and, for one test, in reducing Ar/H2 atmosphere. The iodine and cesium release could be partially explained by the differences in sample preparation, leading to different sizes and properties of the exposed surface areas. Iodine and cesium releases tend to correlate with FGR and linear power rating, but the scatter of the data is significant. Although the gap between the fuel and the cladding was closed in some high burn-up samples, fissures still provide possible preferential transport pathways.

  17. VESPA. Behaviour of long-lived fission and activation products in the nearfield of a nuclear waste repository and the possibilities of their retention

    Energy Technology Data Exchange (ETDEWEB)

    Bischofer, Barbara; Hagemann, Sven [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) gGmbH, Koeln (Germany); Altmaier, Marcus [Karlsruher Institut fuer Technologie (KIT) (Germany); and others

    2016-06-15

    The present document is the final report of the Joint Research Project VESPA (Behaviour of Long-lived Fission and Activation Products in the Near Field of a Nuclear Waste Repository and the Possibilities of Their Retention), started in July 2010 with a duration of four years. The following four institutions were collaborative Partners in VESPA: - Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) gGmbH - Institut fuer Energie- und Klimaforschung, IEK-6: Nukleare Entsorgung und Reaktorsicherheit, Forschungszentrum Juelich (FZJ) - Institut fuer Ressourcenoekologie (IRE), Helmholtz-Zentrum Dresden-Rossendorf (HZDR) - Institut fuer Nukleare Entsorgung (INE), Karlsruher Institut fuer Technologie (KIT) VESPA was funded by the German Federal Ministry of Economics and Energy (BMWi) under the contract numbers 02 E 10770 (GRS), 02 E 10780 (FZJ-IEF-6), 02 E 10790 (HZDR-IRE), 02 E 10800 (KIT-INE).

  18. CHOSEN ASPECTS OF THE PRODUCTION OF THE BASIC MAP USING UAV IMAGERY

    Directory of Open Access Journals (Sweden)

    M. Kedzierski

    2016-06-01

    Full Text Available For several years there has been an increasing interest in the use of unmanned aerial vehicles in acquiring image data from a low altitude. Considering the cost-effectiveness of the flight time of UAVs vs. conventional airplanes, the use of the former is advantageous when generating large scale accurate ortophotos. Through the development of UAV imagery, we can update large-scale basic maps. These maps are cartographic products which are used for registration, economic, and strategic planning. On the basis of these maps other cartographic maps are produced, for example maps used building planning. The article presents an assessesment of the usefulness of orthophotos based on UAV imagery to upgrade the basic map. In the research a compact, non-metric camera, mounted on a fixed wing powered by an electric motor was used. The tested area covered flat, agricultural and woodland terrains. The processing and analysis of orthorectification were carried out with the INPHO UASMaster programme. Due to the effect of UAV instability on low-altitude imagery, the use of non-metric digital cameras and the low-accuracy GPS-INS sensors, the geometry of images is visibly lower were compared to conventional digital aerial photos (large values of phi and kappa angles. Therefore, typically, low-altitude images require large along- and across-track direction overlap – usually above 70 %. As a result of the research orthoimages were obtained with a resolution of 0.06 meters and a horizontal accuracy of 0.10m. Digitized basic maps were used as the reference data. The accuracy of orthoimages vs. basic maps was estimated based on the study and on the available reference sources. As a result, it was found that the geometric accuracy and interpretative advantages of the final orthoimages allow the updating of basic maps. It is estimated that such an update of basic maps based on UAV imagery reduces processing time by approx. 40%.

  19. Chosen Aspects of the Production of the Basic Map Using Uav Imagery

    Science.gov (United States)

    Kedzierski, M.; Fryskowska, A.; Wierzbicki, D.; Nerc, P.

    2016-06-01

    For several years there has been an increasing interest in the use of unmanned aerial vehicles in acquiring image data from a low altitude. Considering the cost-effectiveness of the flight time of UAVs vs. conventional airplanes, the use of the former is advantageous when generating large scale accurate ortophotos. Through the development of UAV imagery, we can update large-scale basic maps. These maps are cartographic products which are used for registration, economic, and strategic planning. On the basis of these maps other cartographic maps are produced, for example maps used building planning. The article presents an assessesment of the usefulness of orthophotos based on UAV imagery to upgrade the basic map. In the research a compact, non-metric camera, mounted on a fixed wing powered by an electric motor was used. The tested area covered flat, agricultural and woodland terrains. The processing and analysis of orthorectification were carried out with the INPHO UASMaster programme. Due to the effect of UAV instability on low-altitude imagery, the use of non-metric digital cameras and the low-accuracy GPS-INS sensors, the geometry of images is visibly lower were compared to conventional digital aerial photos (large values of phi and kappa angles). Therefore, typically, low-altitude images require large along- and across-track direction overlap - usually above 70 %. As a result of the research orthoimages were obtained with a resolution of 0.06 meters and a horizontal accuracy of 0.10m. Digitized basic maps were used as the reference data. The accuracy of orthoimages vs. basic maps was estimated based on the study and on the available reference sources. As a result, it was found that the geometric accuracy and interpretative advantages of the final orthoimages allow the updating of basic maps. It is estimated that such an update of basic maps based on UAV imagery reduces processing time by approx. 40%.

  20. A stability indicating HPLC method for the determination of clobazam and its basic degradation product characterization

    OpenAIRE

    2014-01-01

    Background Clobazam is used for the treatment of different types of seizure and epilepsy. The present research is undertaken to study the systematic forced degradation of clobazam and to identify its main degradation product under basic conditions. Methods The degradation of clobazam was studied under different conditions. Clobazam and its degradation products were separated using a Nova-Pak C18 column and a mixture of KH2PO4 50 mM (pH 8.5) and acetonitrile (50:50, v/v) as the mobile phase wi...

  1. Bias estimates used in lieu of validation of fission products and minor actinides in MCNP Keff calculations for PWR burnup credit casks

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Don [ORNL; Marshall, William BJ J [ORNL; Wagner, John C [ORNL; Bowen, Douglas G [ORNL

    2015-09-01

    The U.S. Nuclear Regulatory Commission (NRC) Division of Spent Fuel Storage and Transportation recently issued Interim Staff Guidance (ISG) 8, Revision 3. This ISG provides guidance for burnup credit (BUC) analyses supporting transport and storage of PWR pressurized water reactor (PWR) fuel in casks. Revision 3 includes guidance for addressing validation of criticality (keff) calculations crediting the presence of a limited set of fission products and minor actinides (FP&MA). Based on previous work documented in NUREG/CR-7109, recommendation 4 of ISG-8, Rev. 3, includes a recommendation to use 1.5 or 3% of the FP&MA worth to conservatively cover the bias due to the specified FP&MAs. This bias is supplementary to the bias and bias uncertainty resulting from validation of keff calculations for the major actinides in SNF and does not address extension to actinides and fission products beyond those identified herein. The work described in this report involves comparison of FP&MA worths calculated using SCALE and MCNP with ENDF/B-V, -VI, and -VII based nuclear data and supports use of the 1.5% FP&MA worth bias when either SCALE or MCNP codes are used for criticality calculations, provided the other conditions of the recommendation 4 are met. The method used in this report may also be applied to demonstrate the applicability of the 1.5% FP&MA worth bias to other codes using ENDF/B V, VI or VII based nuclear data. The method involves use of the applicant s computational method to generate FP&MA worths for a reference SNF cask model using specified spent fuel compositions. The applicant s FP&MA worths are then compared to reference values provided in this report. The applicants FP&MA worths should not exceed the reference results by more than 1.5% of the reference FP&MA worths.

  2. Interconnections of basic science research and product development in medical device design.

    Science.gov (United States)

    Privitera, Mary Beth; Design, M; Johnson, Jeffrey

    2009-01-01

    The relationship between basic science research and product design/development are intertwined. This paper explores the definition of basic science and design as it relates to medical device development. It is intended to serve as a reference for both researchers and device developers to assist in trans-disciplinary collaborative efforts in improving patient care as each are of equal importance. The definition of a medical device is broad and varied. This paper is aimed towards those devices which interact with tissue and are rooted in the tenets of science. Both the scientific method and the design process are compared with similarities and opposites identified. The paper concludes identifying fundamental principles of medical device development and highlights the importance of both entities.

  3. Microscopic dynamical description of proton-induced fission with the Constrained Molecular Dynamics (CoMD) Model

    CERN Document Server

    Vonta, N; Veselsky, M; Bonasera, A

    2015-01-01

    The microscopic description of nuclear fission still remains a topic of intense basic research. Un- derstanding nuclear fission, apart from a theoretical point of view, is of practical importance for energy production and the transmutation of nuclear waste. In nuclear astrophysics, fission sets the upper limit to the nucleosynthesis of heavy elements via the r-process. In this work we initiated a systematic study of intermediate energy proton-induced fission using the Constrained Molecu- lar Dynamics (CoMD) code. The CoMD code implements an effective interaction with a nuclear matter compressibility of K=200 (soft EOS) with several forms of the density dependence of the nucleon-nucleon symmetry potential. Moreover, a constraint is imposed in the phase-space occu- pation for each nucleon restoring the Pauli principle at each time step of the collision. A proper choice of the surface parameter of the effective interaction has been made to describe fission. In this work, we present results of fission calculation...

  4. Management of radioactive waste from {sup 99}Mo production by nuclear fission; Gestao dos rejeitos radioativos gerados na producao do {sup 99}Mo por fissao nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Rego, Maria Eugenia de Melo

    2013-07-01

    Brazil intends to build a facility for the {sup 99}Mo production through {sup 235}U fission, once this radioisotope is largely used in nuclear medicine. This study aimed at estimating the physical, chemical and radiological characteristics of radioactive waste expected to be generated in that facility, and to provide theoretical subsides that can be used on the definition of a proper waste management system. Two production scenarios were established and the radioisotope inventories of the wastes were calculated by Scale®. From the chemical processing of the uranium targets the wastes were characterized on their chemical and radiological features. MicroShield® was used to determine the activity concentrations up to three months of {sup 99}Mo production. In addition, this work presents dose rate calculation for several sizes of shielding and different amount of wastes, collected in a proper package for in-site transportation. Radionuclides responsible for higher doses were identified in order to facilitate choosing the most appropriate method for managing the wastes after their chemical separation and before their storage. These results are part of what is expected on radioactive wastes at a {sup 99}Mo production facility and might help on the development of the waste management planning for that facility. (author)

  5. Absolute fission yields in the fast neutron induced fission of sup 2 sup 3 sup 3 U by track etch combined with gamma-ray spectrometry

    CERN Document Server

    Ramaswami, A; Kalsi, P C; Dange, S P

    2003-01-01

    The absolute fission yields of twenty seven fission products were determined in the fast neutron induced fission of sup 2 '3 sup 3 U, employing track etch in combination with gamma-ray spectrometry. The total number of fissions was measured by registering the fission tracks on a small strip of lexan, a solid state track detector. The fission products were analysed by gamma-ray spectrometry. The measured yield values were compared to the ENDF/B-VI compilation and show a good agreement. (author)

  6. Production Pathways and Separation Procedures for High-Diagnostic-Value Activation Species, Fission Products, and Actinides Required for Preparation of Realistic Synthetic Post-Detonation Nuclear Debris: Status Report and FY16 Project Plan

    Energy Technology Data Exchange (ETDEWEB)

    Faye, S. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Shaughnessy, D. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-08-19

    The objective of this project is to provide a comprehensive study on the production routes and chemical separation requirements for activation products, fission products, and actinides required for the creation of realistic post-detonation surrogate debris. Isotopes that have been prioritized by debris diagnosticians will be examined for their ability to be produced at existing irradiation sources, production rates, and availability of target materials, and chemical separation procedures required to rapidly remove the products from the bulk target matrix for subsequent addition into synthetic debris samples. The characteristics and implications of the irradiation facilities on the isotopes of interest will be addressed in addition to a summary of the isotopes that are already regularly produced. This is a planning document only.

  7. Non destructive localization by gamma tomography of fission products emission in a fuel pencil area after an accidental sequence; Localisation non destructive par tomographie gamma d`emission des produits de fission dans une section de crayon combustible ayant subi une sequence accidentelle

    Energy Technology Data Exchange (ETDEWEB)

    Ducros, G.; Confort, E.; Drevon, P.

    1994-12-31

    The transverse gamma spectrometry of an irradiated fuel pencil, associated to a tomography method of gamma emitters reconstruction in a straight section of the pencil, is a non destructive technique which proves efficient when there are enough projections. For a little irradiated fuel, four to six projections equally distributed on 180 degrees and associated to an activity repartition initial model with symmetry of revolution are generally sufficient. For a very damaged fuel, it is necessary to practice eighteen projections every ten degrees; the initial repartition model is no more a noticeable parameter. Applied to the VERCORS safety programme, it allows to know the fuel behavior in situation of serious accident and the radial migrations of fission products. The localization of gamma emitters fission products brings informations supplementary to others optical techniques (ceramographies), or chemical techniques (micro-probe). Then, by its non destructive aspect, it can be in certain cases, unavoidable in front of usual destructive techniques. (N.C.). 4 refs.

  8. Fifty years of nuclear fission: Nuclear data and measurements series

    Energy Technology Data Exchange (ETDEWEB)

    Lynn, J.E.

    1989-06-01

    This report is the written version of a colloquium first presented at Argonne National Laboratory in January 1989. The paper begins with an historical preamble about the events leading to the discovery of nuclear fission. This leads naturally to an account of early results and understanding of the fission phenomena. Some of the key concepts in the development of fission theory are then discussed. The main theme of this discussion is the topography of the fission barrier, in which the interplay of the liquid-drop model and nucleon shell effects lead to a wide range of fascinating phenomena encompassing metastable isomers, intermediate-structure effects in fission cross-sections, and large changes in fission product properties. It is shown how study of these changing effects and theoretical calculations of the potential energy of the deformed nucleus have led to broad qualitative understanding of the nature of the fission process. 54 refs., 35 figs.

  9. Observation of new neutron-rich micro-second isomers among fission products of ^238U at 345 MeV/u

    Science.gov (United States)

    Kameda, Daisuke; Nakao, Taro; Kubo, Toshiyuki; Ohnishi, Tetsuya; Takeda, Hiroyuki; Fukuda, Naoki; Kusaka, Kensuke; Yoshida, Atsushi; Yoshida, Koichi; Ohtake, Masao; Inabe, Naohito; Yanagisawa, Yoshiyuki; Tanaka, Kanenobu; Gono, Yasuyuki

    2009-10-01

    In the production of the radioactive isotope (RI) beam using projectile fragment separators, γ rays emitted from metastable states, isomers, of the reaction products can be used as a fingerprint of the isotope that is analyzed in the separator. In the operation of the superconducting in-flight RI beam separator BigRIPS [1] at RIKEN RI Beam Factory, the detection of such γ rays plays important roles not only in the identification of the RI beam [2] but also in searching for new isomers, providing valuable spectroscopic information on the isotopes. In the recent new-isotope production experiment with BigRIPS using in-flight fission of 345 MeV/nucleon ^238U at the beam intensity around 0.3 pnA, we have observed a number of short-lived isomeric decays which include unknown decays from more than 10 isotopes, using three clover-type Ge detectors with a beam stopper of aluminum. The primal result of the observations will be reported. [1] T. Kubo: Nucl. Instr. and Meth. B 204 (2003) 97. [2] T. Ohnishi et al.: J. Phys. Soc. Japan, 77 (2008) 083201.

  10. Contribution to the study of the behaviour, in the urban environment, during the runoff of rainwater, of the fission products emitted during a nuclear accident; Contribution a l`etude du devenir, en milieu urbain, pendant le ruissellement des eaux pluviales, des produits de fission emis en cas d`accident nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Pioch, M.

    1993-05-24

    In the context of research into the environmental consequences of a serious accident occurring on a pressurized water reactor, this paper concerns the experimental study of behaviour of five fission products (caesium, strontium, iodine, ruthenium and tellurium) in the urban environment under the action of rainwater. Stable or radioactive multiple-element aerosols were produced. Their physicochemical characteristics and their solubility in rainwater were studied. Caesium and rubidium forms solutions totally and quickly, while strontium is partially soluble (approximately 50 %) and iodine is only slightly soluble. The behaviour of fission products on five urban surfaces was then studied. Batch experiments showed that the retention of dissolved forms of radioelements varied according to the material. The reactions involved are ion exchange reactions. The presence of certain ions in water (in particular NH{sub 4}{sup +}) increase the desorption of radioelements. Using a laboratory rainfall simulator, the re-entrainment of fission products by rainwater was examined. Two modes of deposition and two intensities of rainfall were simulated. The desorption of radioelements is greater after wet deposition and remobilization is reduced by an increase in intensity of rainfall. An addition of NH{sub 4}{sup +} in water is especially effective in the case of wet depositions. Suggestions are made in order to improve experimental protocols and continue the research. (author). 75 refs., 51 figs., 69 tabs., 14 appends.

  11. Application of red mud as a basic catalyst for biodiesel production.

    Science.gov (United States)

    Liu, Qiang; Xin, Ruirui; Li, Chengcheng; Xu, Chunli; Yang, Jun

    2013-04-01

    Red mud was investigated in triglyceride transesterification with a view to determine its viability as a basic catalyst for use in biodiesel synthesis. The effect of calcination temperature on the structure and activity of red mud catalysts was investigated. It was found that highly active catalyst was obtained by simply drying red mud at 200 degrees C. Utilization of red mud as a catalyst for biodiesel production not only provides a cost-effective and environmentally friendly way of recycling this solid red mud waste, significantly reducing its environmental effects, but also reduces the price of biodiesel to make biodiesel competitive with petroleum diesel.

  12. Application of red mud as a basic catalyst for biodiesel production

    Institute of Scientific and Technical Information of China (English)

    Qiang Liu; Ruirui Xin; Chengcheng Li; Chunli Xu; Jun Yang

    2013-01-01

    Red mud was investigated in triglyceride transesterification with a view to determine its viability as a basic catalyst for use in biodiesel synthesis.The effect of calcination temperature on the structure and activity of red mud catalysts was investigated.It was found that highly active catalyst was obtained by simply drying red mud at 200℃.Utilization of red mud as a catalyst for biodiesel production not only provides a cost-effective and environmentally friendly way of recycling this solid red mud waste,significantly reducing its environmental effects,but also reduces the price of biodiesel to make biodiesel competitive with petroleum diesel.

  13. A revised calculational model for fission

    Energy Technology Data Exchange (ETDEWEB)

    Atchison, F.

    1998-09-01

    A semi-empirical parametrization has been developed to calculate the fission contribution to evaporative de-excitation of nuclei with a very wide range of charge, mass and excitation-energy and also the nuclear states of the scission products. The calculational model reproduces measured values (cross-sections, mass distributions, etc.) for a wide range of fissioning systems: Nuclei from Ta to Cf, interactions involving nucleons up to medium energy and light ions. (author)

  14. Effect of basicity on ferromanganese production from beneficiated low-grade manganese ore

    Science.gov (United States)

    Suharno, Bambang; Noegroho, Adi; Ferdian, Deni; Nurjaman, Fajar

    2017-01-01

    Indonesia is known to have a large low-grade manganese ore reserve. Nevertheless, it could not be used optimally in producing ferromanganese due to their low Mn/Fe ratio. In this present study, the beneficiation process had been applied to the low-grade manganese ore. Reduction roasting was conducted to this manganese ore at 700°C for an hour and then continued with low-intensity magnetic separation. This process had improved the Mn/Fe ratio from 1.39 to 6.11. The effect of basicity on ferromanganese production from this beneficiated low-grade manganese ore had been investigated clearly in this experiment by using mini submerged arc furnace (SAF). Several basicities for 0.7 and 1.0, was used and it was controlled by the addition of limestone in this smelting process. From this experiment, the ferromanganese containing 60% Mn was obtained from smelting the beneficiated low-grade manganese ore with the optimum basicity 0.7.

  15. Thermal fission rates with temperature dependent fission barriers

    CERN Document Server

    Zhu, Yi

    2016-01-01

    \\item[Background] The fission processes of thermal excited nuclei are conventionally studied by statistical models which rely on inputs of phenomenological level densities and potential barriers. Therefore the microscopic descriptions of spontaneous fission and induced fission are very desirable for a unified understanding of various fission processes. \\item[Purpose] We propose to study the fission rates, at both low and high temperatures, with microscopically calculated temperature-dependent fission barriers and mass parameters. \\item[Methods] The fission barriers are calculated by the finite-temperature Skyrme-Hartree-Fock+BCS method. The mass parameters are calculated by the temperature-dependent cranking approximation. The thermal fission rates can be obtained by the imaginary free energy approach at all temperatures, in which fission barriers are naturally temperature dependent. The fission at low temperatures can be described mainly as a barrier-tunneling process. While the fission at high temperatures ...

  16. Production of basic chromium sulfate by using recovered chromium from ashes of thermally treated leather.

    Science.gov (United States)

    Dettmer, Aline; Nunes, Keila Guerra Pacheco; Gutterres, Mariliz; Marcílio, Nilson Romeu

    2010-04-15

    Leather wastes tanned with chromium are generated during the production process of leather, hence the wastes from hand crafted goods and footwear industries are a serious environmental problem. The thermal treatment of leather wastes can be one of the treatment options because the wastes are rich in chromium and can be used as a raw material for sodium chromate production and further to obtain several chromium compounds. The objective of this study was to utilize the chromium from leather wastes via basic chromium sulfate production to be subsequently applied in a hide tanning. The obtained results have shown that this is the first successful attempt to achieve desired base properties of the product. The result was achieved when the following conditions were applied: a molar ratio between sodium sulfite and sodium dichromate equal to 6; reaction time equal to 5 min before addition of sulfuric acid; pH of sodium dichromate solution equal to 2. Summarizing, there is an opportunity to utilize the dangerous wastes and reused them in the production scheme by minimizing or annulling the environmental impact and to attend a sustainable process development concept.

  17. Development of a “Fission-proxy” Method for the Measurement of 14-MeV Neutron Fission Yields at CAMS

    Energy Technology Data Exchange (ETDEWEB)

    Gharibyan, Narek [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-10-25

    Relative fission yield measurements were made for 50 fission products from 25.6±0.5 MeV alpha-induced fission of Th-232. Quantitative comparison of these experimentally measured fission yields with the evaluated fission yields from 14-MeV neutron-induced fission of U-235 demonstrates the feasibility of the proposed fission-proxy method. This new technique, based on the Bohr-independence hypothesis, permits the measurement of fission yields from an alternate reaction pathway (Th-232 + 25.6 MeV α → U-236* vs. U-235 + 14-MeV n → U-236*) given that the fission process associated with the same compound nucleus is independent of its formation. Other suitable systems that can potentially be investigated in this manner include (but are not limited to) Pu-239 and U-237.

  18. Production of pre-basic potato seed by polyvinyl chloride PVC: articulate gutters hydroponic system

    Directory of Open Access Journals (Sweden)

    Jonny Everson Scherwinski-Pereira

    2009-10-01

    Full Text Available The development of more efficient and productive systems for pre-basic seed potato production would improve the quality of the propagative material used by the potato growers, directly affecting the crop yields. A two-year experiment was carried out to evaluate the potato pre-basic seed production by two types of hydroponic systems (fibrocement tiles and articulated PVC gutters, two cultivars (`Baronesa` and `Eliza` and two types of propagative material (plants coming from in vitro culture and minitubers. The PVC gutters system was highly efficient. When using minitubers, this system reached multiplication rates up to 74 tubers per plant. Minitubers were more productive than in vitro plants, independent of cultivar and hydroponic system utilized.Um experimento realizado por dois anos consecutivos avaliou a produção de sementes pré-básicas de batata por meio de sistemas de cultivo hidropônico. O trabalho testou a combinação de dois sistemas de cultivo (telha de fibrocimento e calhas de PVC articuladas, duas cultivares (Baronesa e Eliza e dois tipos de material propagativo (plântulas oriundas do cultivo in vitro e minitubérculos. O sistema de calhas de PVC foi altamente eficiente. Quando foi utilizado minitubérculos, este sistema alcançou taxas de multiplicação de até 74 tubérculos por planta. De modo geral, o uso de minitubérculos como material propagativo apresentou os melhores resultados de produtividade quando comparada ao material in vitro, independentemente da cultivar e sistemas hidropônicos utilizados.

  19. Changes of major tea polyphenols and production of four new B-ring fission metabolites of catechins from post-fermented Jing-Wei Fu brick tea.

    Science.gov (United States)

    Zhu, Yun-Fei; Chen, Jing-Jing; Ji, Xiao-Ming; Hu, Xin; Ling, Tie-Jun; Zhang, Zheng-Zhu; Bao, Guan-Hu; Wan, Xiao-Chun

    2015-03-01

    HPLC analysis of samples from four major fermentation procedures of Jing-Wei Fu brick tea showed that the level of major tea catechins epigallocatechin gallate (EGCG) and epicatechin gallate (ECG) dropped increasingly to about 1/3 in the final product. Phytochemical study of the final product led to the discovery of four new B-ring fission metabolites of catechins (BRFCs) Fuzhuanin C-F (1-4) together with three known BRFCs (5-7), six known catechins (8-13), five simple phenols (14-18), seven flavones and flavone glycosides (19-25), two alkaloids (26, 27), three triterpenoids (28-30) and one steroid (31). The structures were elucidated by spectroscopic methods including 1D and 2D NMR, LC-HR-ESI-MS, IR, and CD spectra. Five compounds (16-18, 28, 29) were reported for the first time in tea. Possible pathways for the degradation of major tea catechins and the generation of BRFCs were also provided.

  20. Fission Measurements with Dance

    Science.gov (United States)

    Jandel, M.; Bredeweg, T. A.; Fowler, M. M.; Bond, E. M.; Chadwick, M. B.; Clement, R. R.; Couture, A.; O'Donnell, J. M.; Haight, R. C.; Keksis, A. L.; Reifarth, R.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wilhelmy, J. B.; Wouters, J. M.; Agvaanluvsan, U.; Dashdorj, D.; Macri, R. A.; Parker, W. E.; Wilk, P. A.; Wu, C. Y.; Becker, J. A.; Angell, C. T.; Tonchev, A. P.; Baker, J. D.

    2008-08-01

    Neutron capture cross section measurements on actinides are complicated by the presence of neutron-induced fission. An efficient fission tagging detector used in coincidence with the Detector for Advanced Neutron Capture Experiments (DANCE) provides a powerful tool in undertaking simultaneous measurements of (n,γ) and (n,f) cross sections. Preliminary results on 235U(n,γ) and (n,f) and 242mAm(n,f) cross sections measured with DANCE and a custom fission-tagging parallel plate avalanche counter (PPAC) are presented. Additional measurements of γ-ray cluster multiplicity distributions for neutron-induced fission of 235U and 242mAm and spontaneous fission of 252Cf are shown, as well as γ-ray energy and average γ-ray energy distributions.

  1. Nanocrystalline SiC and Ti3SiC2 Alloys for Reactor Materials: Diffusion of Fission Product Surrogates

    Energy Technology Data Exchange (ETDEWEB)

    Henager, Charles H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jiang, Weilin [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-11-01

    MAX phases, such as titanium silicon carbide (Ti3SiC2), have a unique combination of both metallic and ceramic properties, which make them attractive for potential nuclear applications. Ti3SiC2 has been suggested in the literature as a possible fuel cladding material. Prior to the application, it is necessary to investigate diffusivities of fission products in the ternary compound at elevated temperatures. This study attempts to obtain relevant data and make an initial assessment for Ti3SiC2. Ion implantation was used to introduce fission product surrogates (Ag and Cs) and a noble metal (Au) in Ti3SiC2, SiC, and a dual-phase nanocomposite of Ti3SiC2/SiC synthesized at PNNL. Thermal annealing and in-situ Rutherford backscattering spectrometry (RBS) were employed to study the diffusivity of the various implanted species in the materials. In-situ RBS study of Ti3SiC2 implanted with Au ions at various temperatures was also performed. The experimental results indicate that the implanted Ag in SiC is immobile up to the highest temperature (1273 K) applied in this study; in contrast, significant out-diffusion of both Ag and Au in MAX phase Ti3SiC2 occurs during ion implantation at 873 K. Cs in Ti3SiC2 is found to diffuse during post-irradiation annealing at 973 K, and noticeable Cs release from the sample is observed. This study may suggest caution in using Ti3SiC2 as a fuel cladding material for advanced nuclear reactors operating at very high temperatures. Further studies of the related materials are recommended.

  2. Basic substances under EC 1107/2009 phytochemical regulation: experience with non-biocide and food products as biorationals

    Directory of Open Access Journals (Sweden)

    Marchand Patrice A.

    2016-07-01

    Full Text Available Basic Substances are a newly effective category of Plant Protection Product under EC Regulation No 1107/2009. The first approved application of Equisetum arvense L. opened Part C of Implementing Regulation (EU No 540/2011, which lists the basic substance approved. Although E. arvense was described as a fungicide extract, subsequent applications like chitosan were related to non-biocide molecules. Consequently, plant protection product data were collected from research on alternative or traditional crop protection methods. They are notably issued or derived from foodstuffs (plants, plant by-products, plant derived products, substances and derived substances from animal origin. Applications are currently submitted by our Institute, under evaluation at different stages of the approval process or already approved. Remarkably, this Basic Substance category under pesticide EU Regulation was surprisingly designed for these non-biocidal plant protection products. In fact, components described as the “active substance” of most of the actual applications are food products like sugars and lecithin. Basic Substance applications for these foodstuffs are therefore a straightforward way of easily gaining approval for them. Here we describe the approval context and detail the agricultural uses of theses food products as Biological Control Agents (BCAs or biorationals for crop protection. From all deposited or approved Basic Substance Application (BSA, a proof has been provided that non-biocide and food products via physical barrier or lure effects may be effective plant protection products with an acceptable low profile of concern for public and agricultural safety.

  3. Monte Carlo analysis of the long-lived fission product neutron capture rates at the Transmutation by Adiabatic Resonance Crossing (TARC) experiment

    Energy Technology Data Exchange (ETDEWEB)

    Abanades, A., E-mail: abanades@etsii.upm.es [Grupo de Modelizacion de Sistemas Termoenergeticos, ETSII, Universidad Politecnica de Madrid, c/Ramiro de Maeztu, 7, 28040 Madrid (Spain); Alvarez-Velarde, F.; Gonzalez-Romero, E.M. [Centro de Investigaciones Medioambientales y Tecnologicas (CIEMAT), Avda. Complutense, 40, Ed. 17, 28040 Madrid (Spain); Ismailov, K. [Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8550 (Japan); Lafuente, A. [Grupo de Modelizacion de Sistemas Termoenergeticos, ETSII, Universidad Politecnica de Madrid, c/Ramiro de Maeztu, 7, 28040 Madrid (Spain); Nishihara, K. [Transmutation Section, J-PARC Center, JAEA, Tokai-mura, Ibaraki-ken 319-1195 (Japan); Saito, M. [Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8550 (Japan); Stanculescu, A. [International Atomic Energy Agency (IAEA), Vienna (Austria); Sugawara, T. [Transmutation Section, J-PARC Center, JAEA, Tokai-mura, Ibaraki-ken 319-1195 (Japan)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer TARC experiment benchmark capture rates results. Black-Right-Pointing-Pointer Utilization of updated databases, included ADSLib. Black-Right-Pointing-Pointer Self-shielding effect in reactor design for transmutation. Black-Right-Pointing-Pointer Effect of Lead nuclear data. - Abstract: The design of Accelerator Driven Systems (ADS) requires the development of simulation tools that are able to describe in a realistic way their nuclear performance and transmutation rate capability. In this publication, we present an evaluation of state of the art Monte Carlo design tools to assess their performance concerning transmutation of long-lived fission products. This work, performed under the umbrella of the International Atomic Energy Agency, analyses two important aspects for transmutation systems: moderation on Lead and neutron captures of {sup 99}Tc, {sup 127}I and {sup 129}I. The analysis of the results shows how shielding effects due to the resonances at epithermal energies of these nuclides affects strongly their transmutation rate. The results suggest that some research effort should be undertaken to improve the quality of Iodine nuclear data at epithermal and fast neutron energy to obtain a reliable transmutation estimation.

  4. 裂变产物94Y和95Y半衰期的测定%Half-life determination of fission products 94Y and95Y

    Institute of Scientific and Technical Information of China (English)

    王世联; 白涛; 师全林; 张小林; 凡金龙; 李奇; 刘杰; 卢嘉春; 常永福

    2009-01-01

    用脉冲反应堆热中子辐照浓缩235U溶液靶,经快速放射化学分离纯化出94Y和95Y溶液,稀释并制备放射性浓度依次相差~10倍的3个测量源.将测量源放置在井式HPGe探测器井内,采用质量归一法测得94Y和95Y的半衰期分别为(19.16±0.05)min和(10.36±0.03)min.%Solutions of enriched235U were irradiated in thermal-neutron flux producedby apulsed reactor,and 94Yand 95Y werc separated chemically from the fission products immediately.The purified solution of 94Y and 95Y is diluted aboutten timgs in sequence to three concentration solutions.Three Sources were prepared with the solutions.The sources are measured,from the lower concentration to higher onc,with a well-type HPGe detector to determine the half-life of94Y and95Y.The determined half-life results arg(19.16±0.05)min and(10.35±0.04)min for94Y and 95Y respectively.

  5. SiC layer microstructure in AGR-1 and AGR-2 TRISO fuel particles and the influence of its variation on the effective diffusion of key fission products

    Science.gov (United States)

    Gerczak, Tyler J.; Hunn, John D.; Lowden, Richard A.; Allen, Todd R.

    2016-11-01

    Tristructural isotropic (TRISO) coated particle fuel is a promising fuel form for advanced reactor concepts such as high temperature gas-cooled reactors (HTGR) and is being developed domestically under the US Department of Energy's Nuclear Reactor Technologies Initiative in support of Advanced Reactor Technologies. The fuel development and qualification plan includes a series of fuel irradiations to demonstrate fuel performance from the laboratory to commercial scale. The first irradiation campaign, AGR-1, included four separate TRISO fuel variants composed of multiple, laboratory-scale coater batches. The second irradiation campaign, AGR-2, included TRISO fuel particles fabricated by BWX Technologies with a larger coater representative of an industrial-scale system. The SiC layers of as-fabricated particles from the AGR-1 and AGR-2 irradiation campaigns have been investigated by electron backscatter diffraction (EBSD) to provide key information about the microstructural features relevant to fuel performance. The results of a comprehensive study of multiple particles from all constituent batches are reported. The observations indicate that there were microstructural differences between variants and among constituent batches in a single variant. Insights on the influence of microstructure on the effective diffusivity of key fission products in the SiC layer are also discussed.

  6. Basic Characteristics and Prospects of Production on Hydromeliorated Soils in the Country of Zagreb

    Directory of Open Access Journals (Sweden)

    D. Petošić

    1998-06-01

    Full Text Available The aim of the paper is to point to the current structure and problems of agricultural production on hydroameliorated soils in the County of Zagreb. Based on the recognition of the causes of low economic effects, possibilities and prospects should be pointed out of further production on these areas (soils. The obtained results are mainly based on several year long stationary investigations, primarily of the functionality of the existing drainage systems and the achieved yields of the main agricultural crops. Investigations were carried out on several typical locations in the area of hydroameliorated soils in the County of Zagreb. Hydroameliorated - drained soils make up a considerable part of the total (8.64%, agricultural (15.69% and arable (26.95% land in the County of Zagreb. It should be noted that a large part (3.500 ha or 28% of these land were left uncultivated in 1997. Most of these arable areas (96% are used in agricultural production. Fruit growing accounts for only 3%, and the production of clover-grass mixture for negligible 1% of the overall production on these areas. Agricultural production is based on growing a few basic crops, in which participation of maize and wheat amounts to as much as 80% in some years. The remaining 20% areas are under oil rape, barley and soybean, the proportion of which has shown a sharp decrease in recent years. Results of several years of study point to considerable fluctuation in the yields of the mentioned crops, the average values being below those foreseen for conventional production. Analyses of the basic production indicators allow the conclusion that some financial profit may be realized on hydroameliorated areas (soils in the production of maize, oil rape and wheat. Economic evaluation of investments into drainage of these soils and the realized economic effects of profitable crops, as well as the common credit conditions for such ameliorative practices also indicate that the remaining direct

  7. Radiochemical applications of insoluble sulfate columns. Analytical possibilities in the field of the fission product solutions; Aplicaciones radioquimica de las columnas de precipitados de sulfatos insolubles. Contribucion al estudio de las soluciones envejecidas de productos de fision

    Energy Technology Data Exchange (ETDEWEB)

    Barrachina, M.; Sauvagnac, R.

    1962-07-01

    In this paper we go on with our study of the heterogeneous ion-isotopic exchange in column. At present, we apply it to determine the radiochemical composition of the raw solutions used in the industrial recuperation of the long-lived fission products. The separation of the radioelements contained in these solutions is carried out mainly by making use of small columns, 1-3 cm height, of BaSO{sub 4} or SrSO{sub 4}, under selected experimental conditions. These columns behave like a special type of inorganic exchangers, working by absorption or by ion-isotopic exchange depending on the cases,a nd they provide the means for the selective separation of several important fission products employing very small volumes of fixing and eluting solutions. (Author) 11 refs.

  8. Fission products in National Atmospheric Deposition Program—Wet deposition samples prior to and following the Fukushima Dai-Ichi Nuclear Power Plant incident, March 8?April 5, 2011

    Science.gov (United States)

    Wetherbee, Gregory A.; Debey, Timothy M.; Nilles, Mark A.; Lehmann, Christopher M.B.; Gay, David A.

    2012-01-01

    Radioactive isotopes I-131, Cs-134, or Cs-137, products of uranium fission, were measured at approximately 20 percent of 167 sampled National Atmospheric Deposition Program monitoring sites in North America (primarily in the contiguous United States and Alaska) after the Fukushima Dai-Ichi Nuclear Power Plant incident on March 12, 2011. Samples from the National Atmospheric Deposition Program were analyzed for the period of March 8-April 5, 2011. Calculated 1- or 2-week radionuclide deposition fluxes at 35 sites from Alaska to Vermont ranged from 0.47 to 5,100 Becquerels per square meter during the sampling period of March 15-April 5, 2011. No fission-product isotopes were measured in National Atmospheric Deposition Program samples obtained during March 8-15, 2011, prior to the arrival of contaminated air in North America.

  9. NEW APPROACH TO OIL PALM WOOD UTILIZATION FOR WOODWORKING PRODUCTION Part 1: Basic Properties

    Directory of Open Access Journals (Sweden)

    Jamal Balfas

    2006-03-01

    Full Text Available An explosive development in oil palm plantations in the country has produced a consequence in the generation of  plantation wastes. The  disposal of these wastes  has created  an  enormous environmental problem that some practical solution to their economic utilization has to  be sought.  A series of experiments have been accomplished to observe the possibility of converting the oil palm stem into valuable woodworking products. The  first stage of  this effort was determining basic characteristics of oil palm wood.  Results in general showed that the wood has a great characteristic variation across and along the stem, which may develop problems in its utilization. Characteristics of this wood also vary according to species variety.  Quality degradations of oil palm wood were mostly happened during drying process; hence, modifications to upgrade quality should be undertaken before or within the drying process.

  10. Comparison of (n,2n) and (n,3n) reaction cross sections for fission products in JENDL-3.2 with available experimental and other evaluated cross section data

    Energy Technology Data Exchange (ETDEWEB)

    Manokhin, Vassily N. [Russian Nuclear Data Center, Institute of Physics and Power Engineering (Russian Federation); Odano, Naoteru; Hasegawa, Akira [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-07-01

    In this report, results of comparison of (n,2n) and (n,3n) reaction cross sections for 155 nuclei (Ge-Tb) in JENDL-3.2 with available experimental data, various evaluated data, and those estimated from systematics are summarized to assess validity of cross sections for threshold reactions for fission product nuclei in JENDL-3.2. Plots for comparisons are compiled and issues in cross section data in JENDL-3.2 are also discussed. (author)

  11. Advanced Borobond™ Shields for Nuclear Materials Containment and Borobond™ Immobilization of Volatile Fission Products - Final CRADA Report

    Energy Technology Data Exchange (ETDEWEB)

    Wagh, Arun S. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-05-19

    Borobond is a company-proprietary material developed by the CRADA partner in collaboration with Argonne, and is based on Argonne's Ceramicrete technology. It is being used by DOE for nuclear materials safe storage, and Boron Products, LLC is the manufacturer and supplier of Borobond.

  12. Heterogeneous UO2 fuel irradiated up to a high burn-up: Investigation of the HBS and of fission product releases

    Science.gov (United States)

    Noirot, J.; Lamontagne, J.; Nakae, N.; Kitagawa, T.; Kosaka, Y.; Tverberg, T.

    2013-11-01

    A UO2 fuel with a heterogeneous distribution of 235U was irradiated up to a high burn-up in the Halden Boiling Water Reactor (HBWR). The last 100 days of irradiation were performed with an increased level of linear power. The effect of the heterogeneous fissile isotope distribution on the formation of the HBS was studied free of the possible influence of Pu which exists in heterogeneous MOX fuels. The HBS formed in 235U-rich agglomerates and its main characteristics were very similar to those of the HBS formed in Pu-rich agglomerates of heterogeneous MOX fuels. The maximum local contents of Nd and Xe before HBS formation were studied in this fuel. In addition to a Pu effect that promotes the HBS phenomenon, comparison with previous results for heterogeneous MOX fuels showed that the local fission product concentration was not the only parameter that has to be taken into consideration. It appears that the local actinide depletion by fission and/or the energy locally deposited through electronic interactions in the fission fragment recoils also have an effect on the HBS formation threshold. Moreover, a major release of fission gases from the peripheral 235U-rich agglomerates of HBS bubbles and a Cs radial movement are also evidenced in this heterogeneous UO2. Cs deposits on the peripheral grain boundaries, including the HBS grain boundaries, are considered to reveal the release paths. SUP>235U-rich agglomerates, SUP>235U-poor areas, an intermediate phase with intermediate 235U concentrations. Short fuel rods were fabricated with these pellets. The main characteristics of these fuel rods are shown in Table 1.These rods were irradiated to high burn-ups in the IFA-609/626 of the HBWR and then one was irradiated in the IFA-702 for 100 days. Fig. 2 shows the irradiation history of this fuel. The final average burn-up of the rod was 69 GWd/tU. Due to the flux differences along the rod, however, the average burn-up of the cross section examined was 63 GWd/tU. This fuel

  13. The VERDI fission fragment spectrometer

    Directory of Open Access Journals (Sweden)

    Frégeau M.O.

    2013-12-01

    Full Text Available The VERDI time-of-flight spectrometer is dedicated to measurements of fission product yields and of prompt neutron emission data. Pre-neutron fission-fragment masses will be determined by the double time-of-flight (TOF technique. For this purpose an excellent time resolution is required. The time of flight of the fragments will be measured by electrostatic mirrors located near the target and the time signal coming from silicon detectors located at 50 cm on both sides of the target. This configuration, where the stop detector will provide us simultaneously with the kinetic energy of the fragment and timing information, significantly limits energy straggling in comparison to legacy experimental setup where a thin foil was usually used as a stop detector. In order to improve timing resolution, neutron transmutation doped silicon will be used. The high resistivity homogeneity of this material should significantly improve resolution in comparison to standard silicon detectors. Post-neutron fission fragment masses are obtained form the time-of-flight and the energy signal in the silicon detector. As an intermediary step a diamond detector will also be used as start detector located very close to the target. Previous tests have shown that poly-crystalline chemical vapour deposition (pCVD diamonds provides a coincidence time resolution of 150 ps not allowing complete separation between very low-energy fission fragments, alpha particles and noise. New results from using artificial single-crystal diamonds (sCVD show similar time resolution as from pCVD diamonds but also sufficiently good energy resolution.

  14. Neutron-rich rare isotope production from projectile fission of heavy beams in the energy range of 20 MeV/nucleon

    CERN Document Server

    Vonta, N; Loveland, W D; Kwon, Y K; Tshoo, K; Jeong, S C; Veselsky, M; Bonasera, A; Botvina, A

    2016-01-01

    We investigate the possibilities of producing neutron-rich nuclides in projectile fission of heavy beams in the energy range of 20 MeV/nucleon expected from low-energy facilities. We report our efforts to theoretically describe the reaction mechanism of projectile fission following a multinucleon transfer collision at this energy range. Our calculations are mainly based on a two-step approach: the dynamical stage of the collision is described with either the phenomenological Deep-Inelastic Transfer model (DIT), or with the microscopic Constrained Molecular Dynamics model (CoMD). The deexcitation/fission of the hot heavy projectile fragments is performed with the Statistical Mul- tifragmentation Model (SMM). We compared our model calculations with our previous experimental projectile-fission data of 238U (20 MeV/nucleon)+208Pb and 197Au (20 MeV/nucleon)+197Au and found an overall reasonable agreement. Our study suggests that projectile fission following periph- eral heavy-ion collisions at this energy range of...

  15. Neutron-rich rare-isotope production from projectile fission of heavy nuclei near 20 MeV/nucleon beam energy

    Science.gov (United States)

    Vonta, N.; Souliotis, G. A.; Loveland, W.; Kwon, Y. K.; Tshoo, K.; Jeong, S. C.; Veselsky, M.; Bonasera, A.; Botvina, A.

    2016-12-01

    We investigate the possibilities of producing neutron-rich nuclides in projectile fission of heavy beams in the energy range of 20 MeV/nucleon expected from low-energy facilities. We report our efforts to theoretically describe the reaction mechanism of projectile fission following a multinucleon transfer collision at this energy range. Our calculations are mainly based on a two-step approach: The dynamical stage of the collision is described with either the phenomenological deep-inelastic transfer model (DIT) or with the microscopic constrained molecular dynamics model (CoMD). The de-excitation or fission of the hot heavy projectile fragments is performed with the statistical multifragmentation model (SMM). We compared our model calculations with our previous experimental projectile-fission data of 238U (20 MeV/nucleon) + 208Pb and 197Au (20 MeV/nucleon) + 197Au and found an overall reasonable agreement. Our study suggests that projectile fission following peripheral heavy-ion collisions at this energy range offers an effective route to access very neutron-rich rare isotopes toward and beyond the astrophysical r-process path.

  16. Basic mechanisms of photosynthesis and applications to improved production and conversion of biomass to fuels and chemical products

    Energy Technology Data Exchange (ETDEWEB)

    El-Sayed, M. [Georgia Institute of Tech., Atlanta, GA (United States); Greenbaum, E. [Oak Ridge National Laboratory, TN (United States); Wasielewski, M. [Argonne National Lab., IL (United States)

    1996-09-01

    Natural photosynthesis, the result of 3.5 billion years of evolutionary experimentation, is the best proven, functional solar energy conversion technology. It is responsible for filling the vast majority of humanity`s energy, nutritional, and materials needs. Understanding the basic physical chemical principles underlying photosynthesis as a working model system is vital to further exploitation of this natural technology. These principles can be used to improve or modify natural photosynthesis so that it is more efficient or so that it can produce unusual products such as hydrogen, methane, methanol, ethanol, diesel fuel substitutes, biodegradable materials, or other high value chemical products. Principles garnered from the natural process can also be used to design artificial photosynthetic devices that employ analogs of natural antenna and reaction center function, self-assembly and repair concepts, photoinduced charge transfer processes, photoprotection, and dark reactions that facilitate catalytic action to convert light into, useful chemical or electrical energy. The present broad understanding of many structural and functional aspects of photosynthesis has resulted from rapid recent research progress. X-ray structures of several key photosynthetic reaction centers and antenna systems are available, and the overall principles controlling photoinduced energy and electron transfer are being established.

  17. Study of the fission products fixation in the hydroxyapatite mineral; Estudio de la fijacion de productos de fision en el mineral hidroxiapatita

    Energy Technology Data Exchange (ETDEWEB)

    Soriano R, J. M.

    2011-07-01

    In this research work, sorption properties of hydroxyapatite in aqueous solutions were studied using Na{sup +} and K{sup +} ion behavior. In addition, the fission products {sup 99}Tc and {sup 107}Pd uptake was studied to determine their sorption mechanisms on hydroxyapatite. This research was conducted in two stages. The first stage aimed to identify surface reactive sites of hydroxyapatite surface. This surface study was performed by the radiotracer method using {sup 24}Na and {sup 42}K radionuclides and applying the ion-exchange theory. It provides evidence in terms of the saturation curves of individual behaviour of the Na{sup +} and K{sup +} cations. Hydroxyapatite reactive sites were identified and quantified from the results and application of the ion-exchange model: a mono-functional site of 0.28 mmol g{sup -1} for the sodium hydroxylate form and a dipr otic site with two saturation curves of 0.14 mmol g{sup -1} each, for the sodium phosphate form. In a second stage, the sorption of fission products, Tc and Pd, on hydroxyapatite was studied. This sorption was expressed in terms of distribution coefficients obtained with equivalent radiotracers: {sup 99m}Tc and {sup 109}Pd. Tc presented a low sorption affinity on hydroxyapatite in aqueous medium 0.02 M NaH{sub 2}PO{sub 4} and the results also show that Tc is not sorbed from perchlorate medium (0.01 M Ca(ClO{sub 4}){sub 2}). Sorption behaviour of Pd(II) on hydroxyapatite was studied for different experimental conditions, with parameter such as: ph, aqueous medium (0.01 M NaClO{sub 4}, 0.01 M and 0.025 M Ca(ClO{sub 4}){sub 2}, and 0.02 M NaH{sub 2}PO{sub 4}), the solid solution ratio (10, 4 and 0.020 g/L), and the palladium concentration were studied. Pd sorption was complete at solid-solution ratios 10 and 4 g/L. A strong sorption affinity of hydroxyapatite for palladium was obtained at solid-solution ratio 0.020 g/L. In the interpretation of the results it was considered the aqueous chemistry of palladium

  18. Fission Enhanced diffusion of uranium in zirconia

    CERN Document Server

    Bérerd, N; Moncoffre, N; Sainsot, P; Faust, H; Catalette, H

    2005-01-01

    This paper deals with the comparison between thermal and Fission Enhanced Diffusion (FED) of uranium into zirconia, representative of the inner face of cladding tubes. The experiments under irradiation are performed at the Institut Laue Langevin (ILL) in Grenoble using the Lohengrin spectrometer. A thin $^{235}UO\\_2$ layer in direct contact with an oxidized zirconium foil is irradiated in the ILL high flux reactor. The fission product flux is about 10$^{11}$ ions cm$^{-2}$ s$^{-1}$ and the target temperature is measured by an IR pyrometer. A model is proposed to deduce an apparent uranium diffusion coefficient in zirconia from the energy distribution broadening of two selected fission products. It is found to be equal to 10$^{-15}$ cm$^2$ s$^{-1}$ at 480$\\circ$C and compared to uranium thermal diffusion data in ZrO$\\_2$ in the same pressure and temperature conditions. The FED results are analysed in comparison with literature data.

  19. Evaluation of Nuclear Fission Barrier Parameters for 17 Nuclei

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    As well know that modern nuclear installations and applications have reached a high degree of sophistication. The effective safe and economical design of these technologies require detailed and reliable design calculations. The accuracy of these calculations is largely determined by the accuracy of the basic nuclear and atomic input parameters. In order to meet the needs on high energy fission cross section, fission spectra in waste disposal, transmutation, radioactive beams physics and so on, 17 nuclei fission barrier parameters were collected from the literature based on different experiments and

  20. Mass spectrometry for the determination of fission products 135Cs, 137Cs and 90Sr: A review of methodology and applications

    Science.gov (United States)

    Bu, Wenting; Zheng, Jian; Liu, Xuemei; Long, Kaiming; Hu, Sheng; Uchida, Shigeo

    2016-05-01

    The radioactive fission products 135Cs, 137Cs and 90Sr have been released into the environment by human activities such as nuclear weapon tests, nuclear fuel reprocessing and nuclear power plant accidents. Monitoring of these radionuclides is important for dose assessment. Moreover, the 135Cs/137Cs isotopic ratio can be used as an important long-term fingerprint for radioactive source identification as it varies with weapon, reactor and fuel types. In recent years, mass spectrometry has become a powerful method for the determination of 135Cs, 137Cs and 90Sr in environmental samples. Mass spectrometry is characterized by the high sensitivity and low detection limit and the relatively shorter sample preparation and analysis times compared with radiometric methods. However, the mass spectrometric determination of radiocesium and 90Sr is affected by the peak tailings of the stable nuclides 133Cs and 88Sr, respectively, and the related isobaric and polyatomic interferences. Chemical separation and optimization of the mass spectrometry instrumental setup are strongly needed prior to the mass spectrometry detection. In this paper, we have reviewed the published works about the determination of 135Cs, 137Cs and 90Sr by mass spectrometry. The mass spectrometric techniques we cover are resonance ionization mass spectrometry (RIMS), thermal ionization mass spectrometry (TIMS), accelerator mass spectrometry (AMS) and inductively coupled plasma mass spectrometry (ICP-MS). For each technique, the principles or strategies used for the analysis of these radionuclides are discussed; these included the abundance sensitivity, ways to suppress the interference signals, and the instrumental setup. In particular, the chemical procedures for eliminating the interferences are also summarized. To date, triple quadrupole ICP-MS (ICP-QQQ) showed great ability for the analysis of these radionuclides and the detection limits were as low as 0.01 pg/mL levels. Finally, some investigations on the

  1. Thermal fission rates with temperature dependent fission barriers

    Science.gov (United States)

    Zhu, Yi; Pei, J. C.

    2016-08-01

    Background: The fission processes of thermal excited nuclei are conventionally studied by statistical models which rely on inputs of phenomenological level densities and potential barriers. Therefore the microscopic descriptions of spontaneous fission and induced fission are very desirable for a unified understanding of various fission processes. Purpose: We propose to study the fission rates, at both low and high temperatures, with microscopically calculated temperature-dependent fission barriers and collective mass parameters. Methods: The fission barriers are calculated by the finite-temperature Skyrme-Hartree-Fock+BCS method. The mass parameters are calculated by the temperature-dependent cranking approximation. The thermal fission rates can be obtained by the imaginary free energy approach at all temperatures, in which fission barriers are naturally temperature dependent. The fission at low temperatures can be described mainly as a barrier-tunneling process. While the fission at high temperatures has to incorporate the reflection above barriers. Results: Our results of spontaneous fission rates reasonably agree with other studies and experiments. The temperature dependencies of fission barrier heights and curvatures have been discussed. The temperature dependent behaviors of mass parameters have also been discussed. The thermal fission rates from low to high temperatures with a smooth connection have been given by different approaches. Conclusions: Since the temperature dependencies of fission barrier heights and curvatures, and the mass parameters can vary rapidly for different nuclei, the microscopic descriptions of thermal fission rates are very valuable. Our studies without free parameters provide a consistent picture to study various fissions such as that in fast-neutron reactors, astrophysical environments, and fusion reactions for superheavy nuclei.

  2. Short-Lived Fission Products Yield Measurement for 239pu(nth ,f)%239Pu(nth,f)短寿命裂变产物产额测量

    Institute of Scientific and Technical Information of China (English)

    刘世龙; 杨毅; 冯晶

    2012-01-01

    采用γ能谱相对测量方法,以97Zr为内标参考核素,完成了239Pu( nth,f)短寿命裂变产物88Rb、95Y、101Mo、101Tc、…Csg、142 La等核素的累积产额测量.实验测得88Rb、”Y、101Mo、101Tc、38Csg、142La的累积产额数据分别为(1.32±0.05)%、(4.69±0.22)%、(6.13±0.32)%、(6.10土0.22)%、(6.24±0.24)%、(4.74±o.17)%.对高纯锗探测器中高能端效率刻度、样品封装与辐照、γ谱测量几何条件设计、γ谱测量与数据分析进行了研究.实验测量裂变产物核素分别位于非对称裂变质量分布双驼峰曲线轻峰的左侧、中部和右侧,重峰的中部与右侧.%The cumulative fission yields of short-lived nuclides 88Rb, 95Y, 101Mo, 101Tc, 119 Cs81 and 14!La in thermal neutron induced fission of 230Pu have been determined by gamma-ray spectrometry relative method. "Zr is selected as the reference nuclide. The determined cumulative fission yields are given as following: the Y(88Rb) = (1. 32 + 0. 05) %, Y(95Y) = (4.69 + 0.22)%, Y(101Mo) = (6. 13 + 0. 32 )%, Y(10'Tc)= (6.10 + 0.22)%, Y(I38Cse) = (6. 24 + 0. 24)%, Y(14ELa) = (4. 74 + 0. 17)%. The major work include HPGe detector efficiency calibration, sample sealing and irradiation, gamma-ray measurement and data analysis. The determined nuclides are located in left, middle, right of light group, and in middle, right of heavy group for asymmetric fission model. The accurate yields data supply a gap for domestic nuclear database, and reflect the fission products mass distribution character in thermal neutron induced fission of 239Pu.

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

    Indian Academy of Sciences (India)

    R Tripathi; S Sodaye; K Sudarshan

    2015-08-01

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

  4. Solar Versus Fission Surface Power for Mars

    Science.gov (United States)

    Rucker, Michelle A.; Oleson, Steve; George, Pat; Landis, Geoffrey A.; Fincannon, James; Bogner, Amee; Jones, Robert E.; Turnbull, Elizabeth; McNatt, Jeremiah; Martini, Michael C.; Gyekenyesi, John Z.; Colozza, Anthony J.; Schmitz, Paul C.; Packard, Thomas W.

    2016-01-01

    A multi-discipline team of experts from the National Aeronautics and Space Administration (NASA) developed Mars surface power system point design solutions for two conceptual missions to Mars using In-situ resource utilization (ISRU). The primary goal of this study was to compare the relative merits of solar- versus fission-powered versions of each surface mission. First, the team compared three different solar-power options against a fission power system concept for a sub-scale, uncrewed demonstration mission. This “pathfinder” design utilized a 4.5 meter diameter lander. Its primary mission would be to demonstrate Mars entry, descent, and landing techniques. Once on the Martian surface, the lander’s ISRU payload would demonstrate liquid oxygen propellant production from atmospheric resources. For the purpose of this exercise, location was assumed to be at the Martian equator. The three solar concepts considered included a system that only operated during daylight hours (at roughly half the daily propellant production rate of a round-the-clock fission design), a battery-augmented system that operated through the night (matching the fission concept’s propellant production rate), and a system that operated only during daylight, but at a higher rate (again, matching the fission concept’s propellant production rate). Including 30% mass growth allowance, total payload masses for the three solar concepts ranged from 1,128 to 2,425 kg, versus the 2,751 kg fission power scheme. However, solar power masses increase as landing sites are selected further from the equator, making landing site selection a key driver in the final power system decision. The team also noted that detailed reliability analysis should be performed on daytime-only solar power schemes to assess potential issues with frequent ISRU system on/off cycling.

  5. Intelligent uranium fission converter for neutron production on the periphery of the nuclear reactor core (MARIA reactor in Swierk - Poland)

    Energy Technology Data Exchange (ETDEWEB)

    Gryzinski, M.A.; Wielgosz, M. [National Centre for Nuclear Research, Andrzeja Soltana 7, 05-400 Otwock-Swierk (Poland)

    2015-07-01

    The multipurpose, high flux research reactor MARIA in Otwock - Swierk is an open-pool type, water and beryllium moderated and graphite reflected. There are two not occupied experimental H1 and H2 horizontal channels with complex of empty rooms beside them. Making use of these two channels is not in conflict with other research or commercial employing channels. They can work simultaneously, moreover commercial channels covers the cost of reactor working. Such conditions give beneficial possibility of creating epithermal neutron stand for researches in various field at the horizontal channel H2 of MARIA reactor (co-organization of research at H1 channel is additionally planned). At the front of experimental channels the neutron flux is strongly thermalized - neutrons with energies above 0.625 eV constitute only ∼2% of the total flux. This thermalized neutron flux will be used to achieve high flux of epithermal neutrons at the level of 2x10{sup 9} n cm{sup -2}s{sup -1} by uranium neutron converter (fast neutron production - conversion of reactor core thermal neutrons to fast neutrons - and then filtering, moderating and finally cutting of unwanted gamma radiation). The intelligent converter will be placed in the reactor pool, near the front of the H2 channel. It will replace one graphite block at the periphery of MARIA graphite reflector. The converter will consist of 20 fuel elements - low enriched uranium plates. A fuel plate will be a part which will measure 110 mm wide by 380 mm long and will consist of a thin layer of uranium sealed between two aluminium plates. These plates, once assembled, form the fuel element used in converter. The plates will be positioned vertically. There are several important requirements which should be taken into account at the converter design stage: -maximum efficiency of the converter for neutrons conversion, -cooling of the converter need to be integrated with the cooling circuit of the reactor pool and if needed equipped with

  6. MANTA. An Integral Reactor Physics Experiment to Infer the Neutron Capture Cross Sections of Actinides and Fission Products in Fast and Epithermal Spectra

    Energy Technology Data Exchange (ETDEWEB)

    Youinou, Gilles Jean-Michel [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-10-01

    Neutron cross-sections characterize the way neutrons interact with matter. They are essential to most nuclear engineering projects and, even though theoretical progress has been made as far as the predictability of neutron cross-section models, measurements are still indispensable to meet tight design requirements for reduced uncertainties. Within the field of fission reactor technology, one can identify the following specializations that rely on the availability of accurate neutron cross-sections: (1) fission reactor design, (2) nuclear fuel cycles, (3) nuclear safety, (4) nuclear safeguards, (5) reactor monitoring and neutron fluence determination and (6) waste disposal and transmutation. In particular, the assessment of advanced fuel cycles requires an extensive knowledge of transuranics cross sections. Plutonium isotopes, but also americium, curium and up to californium isotope data are required with a small uncertainty in order to optimize significant features of the fuel cycle that have an impact on feasibility studies (e.g. neutron doses at fuel fabrication, decay heat in a repository, etc.). Different techniques are available to determine neutron cross sections experimentally, with the common denominator that a source of neutrons is necessary. It can either come from an accelerator that produces neutrons as a result of interactions between charged particles and a target, or it can come from a nuclear reactor. When the measurements are performed with an accelerator, they are referred to as differential since the analysis of the data provides the cross-sections for different discrete energies, i.e. σ(Ei), and for the diffusion cross sections for different discrete angles. Another approach is to irradiate a very pure sample in a test reactor such as the Advanced Test Reactor (ATR) at INL and, after a given time, determine the amount of the different transmutation products. The precise characterization of the nuclide densities before and after

  7. Proportioning of {sup 79}Se and {sup 126}Sn long life radionuclides in the fission products solutions coming from spent fuels processing; Dosage des radionucleides a vie longue {sup 79}Se et {sup 126}Sn dans les solutions de produits de fission issues du traitement des combustibles nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Comte, J

    2001-11-01

    The determination of radionuclides present in waste resulting from the nuclear fuel reprocessing is a request from the regulatory authorities to ensure an optimal management of the storage sites. Long-lived radionuclides (T{sub 1/2} > 30 years) are particularly concerned owing to the fact that their impact must be considered for the long term. Safety studies have established a list of long-lived radionuclides (LLRN) whose quantification is essential for the management of the disposal site. Among these, several are pure {beta} emitters, present at low concentration levels in complex matrices. Their determination, by radiochemical method or mass spectrometry, involves selective chemical separations from the others {beta}/{gamma} emitters and from the measurement interfering elements. The work undertaken in this thesis relates to the development of analytical methods for the determination of two long-lived radionuclides: selenium 79 and tin 126, in acid solutions of fission products present in nuclear fuel reprocessing plant. For selenium 79, a {beta} emitter with a half live estimated to be 10{sup 6} years, the bibliography describes different chemical separation methods including precipitation, liquid-liquid extraction and chromatography on ionic resins. After optimisation on a synthetic solution, two of these techniques, precipitation by potassium iodine and separation with ion exchange resins were applied to a genuine solution of fission products at Cogema La Hague. The results showed that only the ion exchange method allows us to obtain a solution sufficiently decontaminated (FD{beta}{gamma} = 250) with a significant selenium recovery yield (85%). This separation allows the measurement of the {sup 79}Se by electrothermal vaporization coupled with inductively coupled plasma mass spectrometry (ETV-ICP/MS), after transfer of the samples to CEA/Cadarache. The concentration of {sup 79}Se measured is 0,42 mg/L in the solution of fission products with an isotopic ratio

  8. The Plinius/Colima CA-U3 test on fission-product aerosol release over a VVER-type corium pool; L'essai Plinius/Colima CA-U3 sur le relachement des aerosols de produits de fission au-dessus d'un bain de corium de type VVER

    Energy Technology Data Exchange (ETDEWEB)

    Journeau, Ch.; Piluso, P.; Correggio, P.; Godin-Jacqmin, L

    2007-07-01

    In a hypothetical case of severe accident in a PWR type VVER-440, a complex corium pool could be formed and fission products could be released. In order to study aerosols release in terms of mechanisms, kinetics, nature or quantity, and to better precise the source term of VVER-440, a series of experiments have been performed in the Colima facility and the test Colima CA-U3 has been successfully performed thanks to technological modifications to melt a prototypical corium at 2760 C degrees. Specific instrumentation has allowed us to follow the evolution of the corium melt and the release, transport and deposition of the fission products. The main conclusions are: -) there is a large release of Cr, Te, Sr, Pr and Rh (>95%w), -) there is a significant release of Fe (50%w), -) there is a small release of Ba, Ce, La, Nb, Nd and Y (<90%w), -) there is a very small release of U in proportion (<5%w) but it is one of the major released species in mass, and -) there is no release of Zr. The Colima experimental results are consistent with previous experiments on irradiated fuels except for Ba, Fe and U releases. (A.C.)

  9. Improved Fission Neutron Data Base for Active Interrogation of Actinides

    Energy Technology Data Exchange (ETDEWEB)

    Pozzi, Sara; Czirr, J. Bart; Haight, Robert; Kovash, Michael; Tsvetkov, Pavel

    2013-11-06

    This project will develop an innovative neutron detection system for active interrogation measurements. Many active interrogation methods to detect fissionable material are based on the detection of neutrons from fission induced by fast neutrons or high-energy gamma rays. The energy spectrum of the fission neutrons provides data to identify the fissionable isotopes and materials such as shielding between the fissionable material and the detector. The proposed path for the project is as follows. First, the team will develop new neutron detection systems and algorithms by Monte Carlo simulations and bench-top experiments. Next, They will characterize and calibrate detection systems both with monoenergetic and white neutron sources. Finally, high-fidelity measurements of neutron emission from fissions induced by fast neutrons will be performed. Several existing fission chambers containing U-235, Pu-239, U-238, or Th-232 will be used to measure the neutron-induced fission neutron emission spectra. The challenge for making confident measurements is the detection of neutrons in the energy ranges of 0.01 – 1 MeV and above 8 MeV, regions where the basic data on the neutron energy spectrum emitted from fission is least well known. In addition, improvements in the specificity of neutron detectors are required throughout the complete energy range: they must be able to clearly distinguish neutrons from other radiations, in particular gamma rays and cosmic rays. The team believes that all of these challenges can be addressed successfully with emerging technologies under development by this collaboration. In particular, the collaboration will address the area of fission neutron emission spectra for isotopes of interest in the advanced fuel cycle initiative (AFCI).

  10. 1.4MeV-5MeV中子诱发238U裂变产额测量%Fission Product Yield Measurement of 238 U Induced by 1.4-5 MeV Neutrons

    Institute of Scientific and Technical Information of China (English)

    李映映; 肖军; 王攀; 李子越; 汪超; 罗小兵

    2016-01-01

    238 U fission yield measurement has a significant meaning in nuclear data measurement .This thesis a-dopts1.4 MeV-5 MeV mono -energetic neutrons generated by 2.5 MeV proton electrostatic accelerator to stimulate 238U fission, and then measures the yield of fission product nuclide 135I、133I、105Ru and 91Sr through measuring fission product radioactivity .Neutron flux during irradiation process is determined by activation meth-od .Subsequently , this thesis analyzes multiple components influencing experiment measurement , including cor-rection on neutron′s multiple scattering and self -shielding effect in target head and sample on the basis of MC-NPX program as well as correction on sample′s self-absorption of γ-ray.Typical deviation of yield data is concluded as 3.5%.Finally, this thesis compares measurement consequences with existing fission yield data .%238 U裂变产额测量工作在核数据测量中有着重要意义,本工作利用2.5MeV质子静电加速器产生的1.4MeV-5MeV单能中子诱发238 U裂变,通过对裂变产物放射性的测量对裂变产物核素135 I、133 I、105 Ru和91 Sr的产额进行了测定。照射过程中中子通量用活化法确定。分析了影响实验测量的多个因素,包括用MCNPX程序对中子在靶头及样品中的多次散射和自屏蔽效应进行了修正,对γ射线在样品中的自吸收进行修正等。得到产额数据典型误差为3.5%,最后把测量结果与已有的裂变产额数据进行比对。

  11. Late Time Emission of Prompt Fission Gamma Rays

    CERN Document Server

    Talou, P; Stetcu, I; Lestone, J P; McKigney, E; Chadwick, M B

    2016-01-01

    The emission of prompt fission $\\gamma$ rays within a few nanoseconds to a few microseconds following the scission point is studied in the Hauser-Feshbach formalism applied to the deexcitation of primary excited fission fragments. Neutron and $\\gamma$-ray evaporations from fully accelerated fission fragments are calculated in competition at each stage of the decay, and the role of isomers in the fission products, before $\\beta$-decay, is analyzed. The time evolution of the average total $\\gamma$-ray energy, average total $\\gamma$-ray multiplicity, and fragment-specific $\\gamma$-ray spectra, is presented in the case of neutron-induced fission reactions of $^{235}$U and $^{239}$Pu, as well as spontaneous fission of $^{252}$Cf. The production of specific isomeric states is calculated and compared to available experimental data. About 7% of all prompt fission $\\gamma$ rays are predicted to be emitted between 10 nsec and 5 $\\mu$sec following fission, in the case of $^{235}$U and $^{239}$Pu $(n_{\\rm th},f)$ reactio...

  12. Fission modelling with FIFRELIN

    Energy Technology Data Exchange (ETDEWEB)

    Litaize, Olivier; Serot, Olivier; Berge, Leonie [CEA, DEN, DER, SPRC, Saint Paul Lez Durance (France)

    2015-12-15

    The nuclear fission process gives rise to the formation of fission fragments and emission of particles (n,γ, e{sup -}). The particle emission from fragments can be prompt and delayed. We present here the methods used in the FIFRELIN code, which simulates the prompt component of the de-excitation process. The methods are based on phenomenological models associated with macroscopic and/or microscopic ingredients. Input data can be provided by experiment as well as by theory. The fission fragment de-excitation can be performed within Weisskopf (uncoupled neutron and gamma emission) or a Hauser-Feshbach (coupled neutron/gamma emission) statistical theory. We usually consider five free parameters that cannot be provided by theory or experiments in order to describe the initial distributions required by the code. In a first step this set of parameters is chosen to reproduce a very limited set of target observables. In a second step we can increase the statistics to predict all other fission observables such as prompt neutron, gamma and conversion electron spectra but also their distributions as a function of any kind of parameters such as, for instance, the neutron, gamma and electron number distributions, the average prompt neutron multiplicity as a function of fission fragment mass, charge or kinetic energy, and so on. Several results related to different fissioning systems are presented in this work. The goal in the next decade will be i) to replace some macroscopic ingredients or phenomenological models by microscopic calculations when available and reliable, ii) to be a support for experimentalists in the design of detection systems or in the prediction of necessary beam time or count rates with associated statistics when measuring fragments and emitted particle in coincidence iii) extend the model to be able to run a calculation when no experimental input data are available, iv) account for multiple chance fission and gamma emission before fission, v) account for

  13. Fission modelling with FIFRELIN

    Science.gov (United States)

    Litaize, Olivier; Serot, Olivier; Berge, Léonie

    2015-12-01

    The nuclear fission process gives rise to the formation of fission fragments and emission of particles (n,γ , e-) . The particle emission from fragments can be prompt and delayed. We present here the methods used in the FIFRELIN code, which simulates the prompt component of the de-excitation process. The methods are based on phenomenological models associated with macroscopic and/or microscopic ingredients. Input data can be provided by experiment as well as by theory. The fission fragment de-excitation can be performed within Weisskopf (uncoupled neutron and gamma emission) or a Hauser-Feshbach (coupled neutron/gamma emission) statistical theory. We usually consider five free parameters that cannot be provided by theory or experiments in order to describe the initial distributions required by the code. In a first step this set of parameters is chosen to reproduce a very limited set of target observables. In a second step we can increase the statistics to predict all other fission observables such as prompt neutron, gamma and conversion electron spectra but also their distributions as a function of any kind of parameters such as, for instance, the neutron, gamma and electron number distributions, the average prompt neutron multiplicity as a function of fission fragment mass, charge or kinetic energy, and so on. Several results related to different fissioning systems are presented in this work. The goal in the next decade will be i) to replace some macroscopic ingredients or phenomenological models by microscopic calculations when available and reliable, ii) to be a support for experimentalists in the design of detection systems or in the prediction of necessary beam time or count rates with associated statistics when measuring fragments and emitted particle in coincidence iii) extend the model to be able to run a calculation when no experimental input data are available, iv) account for multiple chance fission and gamma emission before fission, v) account for the

  14. Solar vs. Fission Surface Power for Mars

    Science.gov (United States)

    Rucker, Michelle A.; Oleson, Steve; George, Pat; Landis, Geoffrey A.; Fincannon, James; Bogner, Amee; Jones, Robert E.; Turnbull, Elizabeth; Martini, Michael C.; Gyekenyesi, John Z.; Colozza, Anthony J.; Schmitz, Paul C.; Packard, Thomas W.

    2016-01-01

    A multi-discipline team of experts from the National Aeronautics and Space Administration (NASA) developed Mars surface power system point design solutions for two conceptual missions. The primary goal of this study was to compare the relative merits of solar- versus fission-powered versions of each surface mission. First, the team compared three different solar power options against a fission power system concept for a sub-scale, uncrewed demonstration mission. The 4.5 meter (m) diameter pathfinder lander's primary mission would be to demonstrate Mars entry, descent, and landing techniques. Once on the Martian surface, the lander's In Situ Resource Utilization (ISRU) payload would demonstrate liquid oxygen propellant production using atmospheric resources. For the purpose of this exercise, location was assumed to be at the Martian equator. The three solar concepts considered included a system that only operated during daylight hours (at roughly half the daily propellant production rate of a round-the-clock fission design), a battery-augmented system that operated through the night (matching the fission concept's propellant production rate), and a system that operated only during daylight, but at a higher rate (again, matching the fission concept's propellant production rate). Including 30% mass growth allowance, total payload masses for the three solar concepts ranged from 1,116 to 2,396 kg, versus the 2,686 kg fission power scheme. However, solar power masses are expected to approach or exceed the fission payload mass at landing sites further from the equator, making landing site selection a key driver in the final power system decision. The team also noted that detailed reliability analysis should be performed on daytime-only solar power schemes to assess potential issues with frequent ISRU system on/off cycling. Next, the team developed a solar-powered point design solution for a conceptual four-crew, 500-day surface mission consisting of up to four landers per

  15. Discoveries of isotopes by fission

    Indian Academy of Sciences (India)

    M Thoennessen

    2015-09-01

    Of the about 3000 isotopes presently known, about 20% have been discovered in fission. The history of fission as it relates to the discovery of isotopes as well as the various reaction mechanisms leading to isotope discoveries involving fission are presented.

  16. Fission dynamics of hot nuclei

    Indian Academy of Sciences (India)

    Santanu Pal; Jhilam Sadhukhan

    2014-04-01

    Experimental evidence accumulated during the last two decades indicates that the fission of excited heavy nuclei involves a dissipative dynamical process. We shall briefly review the relevant dynamical model, namely the Langevin equations for fission. Statistical model predictions using the Kramers’ fission width will also be discussed.

  17. Simple estimate of fission rate during JCO criticality accident

    Energy Technology Data Exchange (ETDEWEB)

    Oyamatsu, Kazuhiro [Faculty of Studies on Contemporary Society, Aichi Shukutoku Univ., Nagakute, Aichi (Japan)

    2000-03-01

    The fission rate during JCO criticality accident is estimated from fission-product (FP) radioactivities in a uranium solution sample taken from the preparation basin 20 days after the accident. The FP radioactivity data are taken from a report by JAERI released in the Accident Investigation Committee. The total fission number is found quite dependent on the FP radioactivities and estimated to be about 4x10{sup 16} per liter, or 2x10{sup 18} per 16 kgU (assuming uranium concentration 278.9 g/liter). On the contrary, the time dependence of the fission rate is rather insensitive to the FP radioactivities. Hence, it is difficult to determine the fission number in the initial burst from the radioactivity data. (author)

  18. Applications of Event-by-Event Fission Modeling with FREYA

    Directory of Open Access Journals (Sweden)

    Vogt R.

    2012-02-01

    Full Text Available The recently developed code FREYA (Fission Reaction Event Yield Algorithm generates large samples of complete fission events, consisting of two receding product nuclei as well as a number of neutrons and photons, all with complete kinematic information. Thus it is possible to calculate arbitrary correlation observables whose behavior may provide unique insight into the fission process. We first discuss the present status of FREYA, which has now been extended to include spontaneous fission. Concentrating on 239Pu(nth,f, 240Pu(sf and 252Cf(sf, we discuss the neutron multiplicity correlations, the dependence of the neutron energy spectrum on the neutron multiplicity, and the relationship between the fragment kinetic energy and the number of neutrons and their energies. We also suggest novel fission observables that could be measured with modern detectors.

  19. Study of the effect of (U{sub 0.8}Pu{sub 0.2})O{sub 2} Uranium-Plutonium mixed fuel fission products on a living organism

    Energy Technology Data Exchange (ETDEWEB)

    Baimukhanova, Ayagoz; Kim, Dmitriy [Dept. of Radiation Protection, Institute of Nuclear Physics of the Ministry of Energy of the Republic of Kazakhstan, Almaty (Kazakhstan); Zhumagulova, Roza; Tazhigulova, Bibnur; Zharaspayeva, Gulzhanar; Azhiyeva, Galiya [Faculty of Engineering Technologies, Infrastructure and Management, International Educational Corporation, Almaty (Kazakhstan)

    2016-08-15

    The article describes the results of experiments conducted on pigs to determine the effect of plutonium, which is the most radiotoxic and highly active element in the range of mixed fuel (U{sub 0.8}Pu{sub 0.2})O{sub 2} fission products, on living organisms. The results will allow empirical prediction of the emergency plutonium radiation dose for various organs and tissues of humans in case of an accident in a reactor running on mixed fuel (U{sub 0.8}Pu{sub 0.2})O{sub 2}.

  20. Caspase cleavage product of BAP31 induces mitochondrial fission through endoplasmic reticulum calcium signals, enhancing cytochrome c release to the cytosol.

    Science.gov (United States)

    Breckenridge, David G; Stojanovic, Marina; Marcellus, Richard C; Shore, Gordon C

    2003-03-31

    Stimulation of cell surface death receptors activates caspase-8, which targets a limited number of substrates including BAP31, an integral membrane protein of the endoplasmic reticulum (ER). Recently, we reported that a caspase-resistant BAP31 mutant inhibited several features of Fas-induced apoptosis, including the release of cytochrome c (cyt.c) from mitochondria (Nguyen, M., D.G. Breckenridge, A. Ducret, and G.C. Shore. 2000. Mol. Cell. Biol. 20:6731-6740), implicating ER-mitochondria crosstalk in this pathway. Here, we report that the p20 caspase cleavage fragment of BAP31 can direct pro-apoptotic signals between the ER and mitochondria. Adenoviral expression of p20 caused an early release of Ca2+ from the ER, concomitant uptake of Ca2+ into mitochondria, and mitochondrial recruitment of Drp1, a dynamin-related protein that mediates scission of the outer mitochondrial membrane, resulting in dramatic fragmentation and fission of the mitochondrial network. Inhibition of Drp1 or ER-mitochondrial Ca2+ signaling prevented p20-induced fission of mitochondria. p20 strongly sensitized mitochondria to caspase-8-induced cyt.c release, whereas prolonged expression of p20 on its own ultimately induced caspase activation and apoptosis through the mitochondrial apoptosome stress pathway. Therefore, caspase-8 cleavage of BAP31 at the ER stimulates Ca2+-dependent mitochondrial fission, enhancing the release of cyt.c in response to this initiator caspase.

  1. Fission modes of mercury isotopes

    CERN Document Server

    Warda, M; Nazarewicz, W

    2012-01-01

    Recent experiments on beta-delayed fission in the mercury-lead region and the discovery of asymmetric fission in $^{180}$Hg [1] have stimulated renewed interest in the mechanism of fission in heavy nuclei. Here we study fission modes and fusion valleys in $^{180}$Hg and $^{198}$Hg using the self-consistent nuclear density functional theory employing Skyrme and Gogny energy density functionals. We show that the observed transition from asymmetric fission in $^{180}$Hg towards more symmetric distribution of fission fragments in $^{198}$Hg can be explained in terms of competing fission modes of different geometries that are governed by shell effects in pre-scission configurations. The density distributions at scission configurations are studied and related to the experimentally observed mass splits.

  2. Dynamical features of nuclear fission

    Indian Academy of Sciences (India)

    Santanu Pal

    2015-08-01

    It is now established that the transition-state theory of nuclear fission due to Bohr and Wheeler underestimates several observables in heavy-ion-induced fusion–fission reactions. Dissipative dynamical models employing either the Langevin equation or equivalently the Fokker–Planck equation have been developed for fission of heavy nuclei at high excitations (T ∼1 MeV or higher). Here, we first present the physical picture underlying the dissipative fission dynamics. We mainly concentrate upon the Kramers’ prescription for including dissipation in fission dynamics. We discuss, in some detail, the results of a statistical model analysis of the pre-scission neutron multiplicity data from the reactions 19F+194,196,198Pt using Kramers’ fission width. We also discuss the multi-dimensional Langevin equation in the context of kinetic energy and mass distribution of the fission fragments.

  3. Weed Control Strategies for Organic Peanut Production and Transition: A Lesson in Basic Agronomy

    Science.gov (United States)

    Weed control in organic peanut production is difficult and costly. The only production inputs that consistently improved weed management in organic peanut production were modified production practices and intense cultivation with a tine weeder. Research trials evaluated row patterns, seeding rates...

  4. Linking the Success of a Basic Skills Program to Workplace Practices and Productivity: An Evaluation.

    Science.gov (United States)

    Lazar, Meryl K.; Bean, Rita M.; Van Horn, Barbara

    1998-01-01

    Describes a workplace literacy project implemented at a hospital with help from a university and a literacy organization. Finds significant changes in all basic skill areas and improvement in job performance, attitude, and self-esteem. Argues that well-designed programs improve employee job performance when program success is closely linked to…

  5. GPM Ground Validation Basic Radar Products and Implications for Observation Strategies

    CERN Document Server

    Yuter, S; Michelle, S D; Hagen, M; Illingworth, A J; Shimizu, S; Wolff, D

    2004-01-01

    Recommendations are made for NASA/JAXA Global Precipitation Measurement (GPM) satellite Ground Validation (GV) program. This report details recommended GV site local radar products based on data from surface-based scanning radars including S-band, C-band, and X-band polarimetric and non-polarimetric radars. Three general categories of products are described: text products summarizing information on the statistical characteristics of the radar data and derived parameters, 2D products providing maps of the horizontal variability of near surface radar observed and derived parameters, and 3D products describing volumetric echo structure. Regional composites could include products based on several of the 2D and 3D single radar products. Several types of time-integrated 2D and 3D products are also recommended. A brief discussion of useful ancillary data from other sources and remaining challenges concludes the report.

  6. Microwave-assisted low temperature synthesis of sodium zirconium phosphate (NZP) and the leachability of some selected fission products incorporated in its structure - A case study of leachability of cesium

    Indian Academy of Sciences (India)

    A H Naik; S B Deb; A B Chalke; M K Saxena; K L Ramakumar; V Venugopal; S R Dharwadkar

    2010-01-01

    Microwave-assisted procedure for low temperature solid state synthesis of sodium zirconium phosphate (NZP), a material with the potential for immobilization and disposal of high level nuclear waste, was developed. Three selected fission products, namely, Cesium, Strontium and Tellurium were introduced (substituted) in the NZP matrix during its synthesis at 450°C. Leaching studies were carried out on the fission product substituted NZP sintered at 1000°C, in pure de-ionized water and 80% saturated brine solution at the ambient temperatures of 30°C and 90°C for four weeks. The major part of leaching in all the cases was observed in the first week. The extent of leaching after four weeks was found not exceeded from 12 to 15% of the elements substituted in NZP, which later became negligibly small. The effect of temperature and the nature of leachant on the leaching rate did not indicate any systematic trend. The EDX analysis of the surfaces of the leached NZP pellets showed that the leaching of the dopants is limited mainly to the surface region of the sintered pellets.

  7. Integrated analysis of remote sensing products from basic geological surveys. [Brazil

    Science.gov (United States)

    Dasilvafagundesfilho, E. (Principal Investigator)

    1984-01-01

    Recent advances in remote sensing led to the development of several techniques to obtain image information. These techniques as effective tools in geological maping are analyzed. A strategy for optimizing the images in basic geological surveying is presented. It embraces as integrated analysis of spatial, spectral, and temporal data through photoptic (color additive viewer) and computer processing at different scales, allowing large areas survey in a fast, precise, and low cost manner.

  8. Microscopic theory of nuclear fission: a review

    Science.gov (United States)

    Schunck, N.; Robledo, L. M.

    2016-11-01

    This article reviews how nuclear fission is described within nuclear density functional theory. A distinction should be made between spontaneous fission, where half-lives are the main observables and quantum tunnelling the essential concept, and induced fission, where the focus is on fragment properties and explicitly time-dependent approaches are often invoked. Overall, the cornerstone of the density functional theory approach to fission is the energy density functional formalism. The basic tenets of this method, including some well-known tools such as the Hartree-Fock-Bogoliubov (HFB) theory, effective two-body nuclear potentials such as the Skyrme and Gogny force, finite-temperature extensions and beyond mean-field corrections, are presented succinctly. The energy density functional approach is often combined with the hypothesis that the time-scale of the large amplitude collective motion driving the system to fission is slow compared to typical time-scales of nucleons inside the nucleus. In practice, this hypothesis of adiabaticity is implemented by introducing (a few) collective variables and mapping out the many-body Schrödinger equation into a collective Schrödinger-like equation for the nuclear wave-packet. The region of the collective space where the system transitions from one nucleus to two (or more) fragments defines what are called the scission configurations. The inertia tensor that enters the kinetic energy term of the collective Schrödinger-like equation is one of the most essential ingredients of the theory, since it includes the response of the system to small changes in the collective variables. For this reason, the two main approximations used to compute this inertia tensor, the adiabatic time-dependent HFB and the generator coordinate method, are presented in detail, both in their general formulation and in their most common approximations. The collective inertia tensor enters also the Wentzel-Kramers-Brillouin (WKB) formula used to extract

  9. Examination of Hybrid Metal Coatings for Mitigation of Fission Product Release and Corrosion Protection of LWR SiC/SiC

    Energy Technology Data Exchange (ETDEWEB)

    Ang, Caen K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Burns, Joseph R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Terrani, Kurt A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Katoh, Yutai [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-01

    There is a need to increase the safety margins of current and future light water reactors (LWRs) due to the unfortunate events at Fukushima Daiichi Nuclear Plant. Safety is crucial to restore public confidence in nuclear energy, acknowledged as an economical, high-­density energy solution to climate change. The development of accident-­tolerant fuel (ATF) concepts is crucial to this endeavor. The objective of ATF is to delay the consequences of accident progression, being inset in high temperature steam and maintaining high thermomechanical strength for radionuclide retention. The use of advanced SiCf-­SiC composite as a substitute for zircaloy-­based cladding is being considered. However, at normal operations, SiC is vulnerable to the reactor coolant and may corrode at an unacceptable rate. As a ceramic-­matrix composite material, it is likely to undergo microcracking operation, which may compromise the ability to contain gaseous fission products. A proposed solution to both issues is the application of mitigation coatings for use in normal operations. At Oak Ridge National Laboratory (ORNL), three coating technologies have been investigated with industry collaborators and vendors. These are electrochemical deposition, cathodic arc physical vapor deposition (PVD hereafter) and vacuum plasma spray (VPS). The objective of this document is to summarize these processing technologies, the resultant as-­processed microstructures and properties of the coatings. In all processes, substrate constraint resulted in substantial tensile stresses within the coating layer. Each technology must mitigate this tensile stress. Electrochemical coatings use chromium as the coolant facing material, and are deposited on a nickel or carbon “bond coat”. This is economical but suffers microcracking in the chromium layer. PVD-­based coatings use chromium and titanium in both metallic form and nitrides, and can be deposited defense-­in-­depth as multilayers. This vapor method

  10. Fission of actinides using a table-top laser

    CERN Document Server

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

    2003-01-01

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

  11. Propagation of a constant velocity fission wave

    Science.gov (United States)

    Deinert, Mark

    2011-10-01

    The ideal nuclear fuel cycle would require no enrichment, minimize the need fresh uranium, and produce few, if any, transuranic elements. Importantly, the latter goal would be met without the reprocessing. For purely physical reasons, no reactor system or fuel cycle can meet all of these objectives. However, a traveling-wave reactor, if feasible, could come remarkably close. The concept is simple: a large cylinder of natural (or depleted) uranium is subjected to a fast neutron source at one end, the neutrons would transmute the uranium downstream and produce plutonium. If the conditions were right, a self-sustaining fission wave would form, producing yet more neutrons which would breed more plutonium and leave behind little more than short-lived fission products. Numerical studies have shown that fission waves of this type are also possible. We have derived an exact solution for the propagation velocity of a fission wave through fertile material. The results show that these waves fall into a class of traveling wave phenomena that have been encountered in other systems. The solution places a strict conditions on the shapes of the flux, diffusive, and reactive profiles that would be required for such a phenomenon to persist. The results are confirmed numerically.

  12. The wastes of nuclear fission; Les dechets de la fission nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Doubre, H. [Paris-11 Univ., Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, IN2P3/CNRS, 91 - Orsay (France)

    2005-07-01

    In this paper the author presents the problems of the radioactive wastes generated by the nuclear fission. The first part devoted to the fission phenomenon explains the incident neutron energy and the target nuclei role. The second part devoted to the nuclear wastes sources presents the production of wastes upstream of the reactors, in the reactors and why these wastes are dangerous. The third part discusses the radioactive wastes management in France (classification, laws). The last part details the associated research programs: the radionuclides separation, the disposal, the underground storage, the transmutation and the thorium cycle. (A.L.B.)

  13. Separation of proton-induced fission isotopes from dominant evaporation residues by adapted target stacking

    NARCIS (Netherlands)

    Beijers, JPM; Duijvestijn, MC; Fraiquin, H; van Klinken, J; Ostendorf, RW

    1999-01-01

    To study low yields of fission products from proton-induced reactions we introduce two activation methods based on target stacking with suppression of otherwise dominating evaporation and spallation products; one method using thin Mylar foils which only transmit the fission products, the other one u

  14. Calculation of 239Pu fission observables in an event-by-event simulation

    Energy Technology Data Exchange (ETDEWEB)

    Vogt, R; Randrup, J; Pruet, J; Younes, W

    2010-03-31

    The increased interest in more exclusive fission observables has demanded more detailed models. We describe a new computational model, FREYA, that aims to meet this need by producing large samples of complete fission events from which any observable of interest can then be extracted consistently, including any interesting correlations. The various model assumptions are described and the potential utility of the model is illustrated. As a concrete example, we use formal statistical methods, experimental data on neutron production in neutron-induced fission of {sup 239}Pu, along with FREYA, to develop quantitative insights into the relation between reaction observables and detailed microscopic aspects of fission. Current measurements of the mean number of prompt neutrons emitted in fission taken together with less accurate current measurements for the prompt post-fission neutron energy spectrum, up to the threshold for multi-chance fission, place remarkably fine constraints on microscopic theories.

  15. Fission approach to cluster radioactivity

    Indian Academy of Sciences (India)

    D N Poenaru; R A Gherghescu

    2015-09-01

    Fission theory is used to explain decay. Also, the analytical superasymmetric fission (ASAF) model is successfully employed to make a systematic search and to predict, with other models, cluster radioactivity. The macroscopic–microscopic method is illustrated for the superheavy nucleus 286Fl. Then a few results of the theoretical approach of decay (ASAF, UNIV and semFIS models), cluster decay (ASAF and UNIV) and spontaneous fission dynamics are described with Werner–Wheeler and cranking inertia. UNIV denotes universal curve and semFIS the fission-based semiempirical formula.

  16. Hidden systematics of fission channels

    Directory of Open Access Journals (Sweden)

    Schmidt Karl-Heinz

    2013-12-01

    Full Text Available It is a common procedure to describe the fission-fragment mass distributions of fissioning systems in the actinide region by a sum of at least 5 Gaussian curves, one for the symmetric component and a few additional ones, together with their complementary parts, for the asymmetric components. These components have been attributed to the influence of fragment shells, e.g. in the statistical scission-point model of Wilkins, Steinberg and Chasman. They have also been associated with valleys in the potential-energy landscape between the outer saddle and the scission configuration in the multi-channel fission model of Brosa. When the relative yields, the widths and the mean mass-asymmetry values of these components are fitted to experimental data, the mass distributions can be very well reproduced. Moreover, these fission channels are characterised by specific values of charge polarisation, total kinetic energy and prompt-neutron yields. The present contribution investigates the systematic variation of the characteristic fission-channel properties as a function of the composition and the excitation energy of the fissioning system. The mean position of the asymmetric fission channels in the heavy fragment is almost constant in atomic number. The deformation of the nascent fragments at scission, which is the main source of excitation energy of the separated fission fragments ending up in prompt-neutron emission, is found to be a unique function of Z for the light and the heavy fragment of the asymmetric fission channels. A variation of the initial excitation energy of the fissioning system above the fission saddle is only seen in the neutron yield of the heavy fragment. The charge polarisation in the two most important asymmetric fission channels is found to be constant and to appreciably exceed the macroscopic value. The variation of the relative yields and of the positions of the fission channels as a function of the composition and excitation energy

  17. Side chain alkylation of toluene with methanol over basic zeolites - novel production route towards styrene?

    NARCIS (Netherlands)

    Rep, Marco

    2002-01-01

    Styrene is an important monomer for the production of different types of (co-) polymers that are used in, e.g., toys, medical devices, food packaging, paper coatings etc. Styrene is produced with several different industrial processes. In 1998, the production of styrene monomer was approximately 21

  18. Fusion-Fission process and gamma spectroscopy of binary products in light heavy ion collisions (40 {<=} A{sub CN} {<=} 60); Processus de fusion-fission et spectroscopie gamma des produits binaires dans les collisions entre ions lourds legers (40 {<=} A{sub NC} {<=} 60)

    Energy Technology Data Exchange (ETDEWEB)

    Nouicer, Rachid [Institut de Recherche Subatomique, CNRS-IN2P3 - Universite Louis Pasteur, 67 - Strasbourg (France)

    1997-11-21

    During the work on which this Thesis is based, the significant role of the Fusion-Fission Asymmetric mechanism in light heavy ion collisions (A{sub NC} {<=} 60) has been emphasized. The Spin Dis-alignment in the oblate-oblate system has supplied evidence for the first time for the Butterfly mode in a resonant-like reaction. These two aspects, one macroscopic and the other more closely related to microscopic effects are certainly different from a conceptual point of view but are quite complementary for a global understanding of dinuclear systems. In the first part, inclusive and exclusive measurements of the {sup 35}Cl + {sup 12}C and {sup 35}Cl + {sup 24}Mg reaction have been performed at 8 MeV/nucleon in the Saclay experiment. These measurements have permitted us to verify the origin of products which have given rise of the asymmetric fusion-fission mechanism and which have demonstrated that the three-body process in this energy range is very weak. In the second part the {sup 28}Si + {sup 28}Si reaction has been performed at the resonance energy E{sub lab}> = 111.6 MeV at Strasbourg with the Eurogam phase II multi-detector array and VIVITRON accelerator. An angular momentum J{sup {pi}} 38{sup +} for inelastic and mutual channels of the {sup 28}Si + {sup 28}Si exit channel has been measured and has supplied evidence for a spin dis-alignment which has been interpreted in the framework of a molecular model by Butterfly motion. The spectroscopic study of {sup 32}S nucleus, has revealed the occurrence of a new {gamma}-ray transition 0{sup +}(8507.8 keV) {yields} 2{sub 1}{sup +}(2230.2 keV). (author) 105 refs., 116 figs., 26 tabs.

  19. Undergraduate Measurements For Fission Reactor Applications

    Science.gov (United States)

    Hicks, S. F.; Kersting, L. J.; Lueck, C. J.; McDonough, P.; Crider, B. P.; McEllistrem, M. T.; Peters, E. E.; Vanhoy, J. R.

    2011-06-01

    Undergraduate students at the University of Dallas (UD) have investigated elastic and inelastic neutron scattering cross sections on structural materials important for criticality considerations in nuclear fission processes. Neutrons scattered off of 23Na and NatFe were detected using neutron time-of-flight techniques at the University of Kentucky Low-Energy Nuclear Accelerator Facility. These measurements are part of an effort to increase the efficiency of power generation from existing fission reactors in the US and in the design of new fission systems. Students have learned the basics of how to operate the Model CN Van de Graaff generator at the laboratory, setup detectors and electronics, use data acquisition systems, and they are currently analyzing the angular dependence of the scattered neutrons for incident neutron energies of 3.57 and 3.80 MeV. Most students participating in the project will use the research experience as the material for their undergraduate research thesis required for all Bachelor of Science students at the University of Dallas. The first student projects on this topic were completed during the summer of 2010; an overview of student participation in this investigation and their preliminary results will be presented.

  20. Technical manual for basic version of the Markov chain nest productivity model (MCnest)

    Science.gov (United States)

    The Markov Chain Nest Productivity Model (or MCnest) integrates existing toxicity information from three standardized avian toxicity tests with information on species life history and the timing of pesticide applications relative to the timing of avian breeding seasons to quantit...

  1. User’s manual for basic version of MCnest Markov chain nest productivity model

    Science.gov (United States)

    The Markov Chain Nest Productivity Model (or MCnest) integrates existing toxicity information from three standardized avian toxicity tests with information on species life history and the timing of pesticide applications relative to the timing of avian breeding seasons to quantit...

  2. Laser Inertial Fusion-based Energy: Neutronic Design Aspects of a Hybrid Fusion-Fission Nuclear Energy System

    OpenAIRE

    Kramer, Kevin James

    2010-01-01

    This study investigates the neutronics design aspects of a hybrid fusion-fission energy system called the Laser Fusion-Fission Hybrid (LFFH). A LFFH combines current Laser Inertial Confinement fusion technology with that of advanced fission reactor technology to produce a system that eliminates many of the negative aspects of pure fusion or pure fission systems. When examining the LFFH energy mission, a significant portion of the United States and world energy production could be supplied by ...

  3. Promotion for underground coal gassification how basic clean technologies for production of energy

    OpenAIRE

    2008-01-01

    Underground Coal Gasification (UCG) is a potential source of future energy production that is currently receiving an increased level of attention within business, academic and policy communities. The principle of UCG is to access coal which either lies too deep underground, or is economically unattractive to exploit for conventional mining methods. Coal gasification converts solid coal into a gas that can be used for power generation, chemical production, as well as the option ...

  4. Production of singlet oxygen by the reaction of non-basic hydrogen peroxide with chlorine gas.

    Science.gov (United States)

    Tian, Wenming; Shi, Wenbo; Yang, Heping; Cui, Rongrong; Deng, Liezheng

    2012-10-14

    Non-basic hydrogen peroxide was found to be very easy to react with Cl(2) to produce singlet oxygen O(2)(a(1)Δ(g)) (i.e. the molecular oxygen in its first electronic excited state) when an H(+) absorbent such as C(5)H(5)N, CH(3)COONH(4), HCOONH(4) or NH(4)F was added into H(2)O(2) aqueous solution, and the long concealed fact that molecular H(2)O(2) can react with Cl(2) to produce O(2)(a(1)Δ(g)) was then uncovered. It is only when an H(+) absorbent has provided a stronger base than H(2)O to absorb the H(+) produced during the reaction that O(2)(a(1)Δ(g)) can be produced.

  5. A basic strategy to manage global health with reference to livestock production in Asia.

    Science.gov (United States)

    Hall, David C; Le, Quynh Ba

    2011-01-01

    Newly emerging infectious diseases (nEIDs) have increased rapidly presenting alarming challenges to global health. We argue that for effective management of global health a basic strategy should include at least three essential tactical forms: actions of a directly focused nature, institutional coordination, and disciplinary integration in approaches to health management. Each level of action is illustrated with examples from the livestock sector in Asia. No clear example of all three tactical forms in place can be found from developing countries where food security is a significant threat although Vietnam is developing a comprehensive strategy. Finally, an ecosystem health approach to global health management is advocated; such an approach moves away from the traditional single disciplinary approach. Stronger guidance is needed to direct ecohealth research and application in the management of global health.

  6. A Basic Strategy to Manage Global Health with Reference to Livestock Production in Asia

    Directory of Open Access Journals (Sweden)

    David C. Hall

    2011-01-01

    Full Text Available Newly emerging infectious diseases (nEIDs have increased rapidly presenting alarming challenges to global health. We argue that for effective management of global health a basic strategy should include at least three essential tactical forms: actions of a directly focused nature, institutional coordination, and disciplinary integration in approaches to health management. Each level of action is illustrated with examples from the livestock sector in Asia. No clear example of all three tactical forms in place can be found from developing countries where food security is a significant threat although Vietnam is developing a comprehensive strategy. Finally, an ecosystem health approach to global health management is advocated; such an approach moves away from the traditional single disciplinary approach. Stronger guidance is needed to direct ecohealth research and application in the management of global health.

  7. NUCLEOTIDE DEGRADATION PRODUCTS, TOTAL VOLATILE BASIC NITROGEN, SENSORY AND MICROBIOLOGICAL QUALITY OF NILE PERCH (LATES NILOTICUS FILLETS UNDER CHILLED STORAGE

    Directory of Open Access Journals (Sweden)

    Andrew Kiri Amegovu

    2012-10-01

    Full Text Available Degradation products of adenosine nucleotide and total volatile basic nitrogen (TVBN concentration provide means of ascertaining freshness of commercial fish products. A complementary sensory analysis has also been adopted by export markets for assessing the quality of fresh fish. Nucleotide breakdown products and TVBN was determined in fresh fillets from beach seined and gill netted Nile perch, a highly commercialized freshwater fish from Lake Victoria (Uganda, under chilled storage. Microbiological and sensory qualities were also evaluated. Total plate and Pseudomonas spp. counts positively correlated with TVBN. Basing on sensory, microbiological and biochemical attributes of the fillets, shelf-life of gill netted Nile perch was lower (13 days than that of the beach seined (17 days. Fillets of beach seined Nile perch have a better keeping quality than that of the gill netted.

  8. Spatially resolved modelling of the fission product behaviour in a HTR-core with spherical or prismatic fuel elements; Raeumlich hoch aufgeloeste Modellierung des Spaltproduktverhaltens in einem HTR-Core mit kugelfoermigen oder prismatischen Brennelementen

    Energy Technology Data Exchange (ETDEWEB)

    Xhonneux, Andre

    2014-07-01

    One of the most important aspects during the licensing procedure of nuclear facilities is the release of radioactive isotopes. The transport from the origin to the environment is called release chain. In the scope of this work, the spatially distributed fission product release from both spherical and prismatic fuel elements, the transport with the coolant as well as the deposition on reactor internals are simulated in detail. The fission product release codes which were developed at Forschungszentrum Juelich are analyzed, shortcomings are identified and resolved. On this basis, a consistent simulation module, named STACY, was developed, which contains all capabilities of the stand-alone codes and at the same time exceeds the methodology towards new aspects. The physics models were extended, for example to take the radial temperature profile within the fuel element and the realistic time-depending nuclide inventory into account. A central part of this work is the automated treatment of the release behavior of a representative number of fuel elements. This allows for a spatially resolved release calculation, where an individual release rate is calculated for each space region. The coupling with the depletion code Topological Nuclide Transmutation (TNT) allows for conducting an individual depletion calculation for each considered fuel element. It is shown, that the released inventory is representative for a certain number of fuel elements. By using this model, the fission product release is being studied for a reference plant (HTR-Modul). Both the releases from the equilibrium core as well as the release during a core heat-up after a fast depressurization accident are being studied. In comparison to former studies, the cumulative release of long-lived nuclides during the core heat-up phase is lower and the release of short-lived nuclides is about two times higher. The release calculation can also be conducted for prismatic fuel elements (e.g. those of the Japanese

  9. Fission and Properties of Neutron-Rich Nuclei - Proceedings of the Second International Conference

    Science.gov (United States)

    Hamilton, J. H.; Phillips, W. R.; Carter, H. K.

    Long Range Alpha Emission Probabilities in the Thermal and Resonance for 239Pu * Spectroscopy of Selected Fission Fragments * Gamma-Ray Spectra of Individual Fission Products * Gamma Spectroscopy of the Transfermium Nucleus Nobelium-254 * Summary of the Yield Values from Fast Fission of 233U Measured of Studsvik * Decay Studies of Neutron-Rich Isotopes Produced in Proton-Induced Fission of Actinides * Understanding of the Fission Process From the Deformation Properties of Fissioning Nuclei * Heavy Clusterization in 252Cf: An Application of the U(3) Selection Rule * Synthesis of Superheavy Elements with Three-Dimensional Fluctuation-Dissipation Dynamical Model * Asymmetric Fission Along Nuclear Lattice Planes * Experimental Study of Correlations Between Fission Neutron Multiplicity, Mass and Kinetic Energy of Fission Fragments From Spontaneous Fission of 252Cf, 244Cm and 248Cm * Super- and Hyper-Deformed Isomeric States and Long-Lived Superheavy Elements * Systematic Investigation of the Neutron Induced Fission Reaction 235, 238U and 237Np below 6 MeV * Studying Iso-chains with RNBs * Cold Fission Studies with Large Detector Arrays * Single-Particle States in Transcurium Nuclei * Shell Effects and Fission of Superheavy Nuclei at Low Excitation Energies * Experiments on the Synthesis of Superheavy Nuclei in 48Ca-Induced Reactions * GSI Experiments on the Synthesis of Superheavy Elements - Results and Plans for the Future * Spectroscopy of Refractory Fission Products at IGISOL * Ternary Fission Induced by Polarized Neutrons * Neutron Decay of Ternary Particles in Spontaneous Fission of 252Cf * New Fission Modes * Alpha Clustering and Ternary Fission * Interplay of Fusion and Fission Dynamics * Applications of the Hartree Bogoliubov Model to Nuclei with Large Isospin Values * Structure of Neutron-Rich Pd Isotopes * Systematic Studies of Fission Saddle-Point Shapes and Their Relation to the Maxima of the Fission-Fragment Mass and Kinetic-Energy Distributions * Limits of

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

    Directory of Open Access Journals (Sweden)

    H. Naik

    2015-08-01

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

  11. Membrane biology: fission behind BARs.

    Science.gov (United States)

    Haucke, Volker

    2012-06-05

    Membrane bending is accomplished in part by amphipathic helix insertion into the bilayer and the assembly of BAR domain scaffolds preparing the membrane for fission. Two recent studies highlight the roles of amphipathic helices and BAR scaffolds in membrane fission and establish the structural basis of membrane bending by the N-BAR protein endophilin.

  12. The organic agricultural waste as a basic source of biohydrogen production

    Science.gov (United States)

    Sriwuryandari, Lies; Priantoro, E. Agung; Sintawardani, Neni; Astuti, J. Tri; Nilawati, Dewi; Putri, A. Mauliva Hada; Mamat, Sentana, Suharwadji; Sembiring, T.

    2016-02-01

    Biohydrogen production research was carried out using raw materials of agricultural organic waste that was obtained from markets around the Bandung city. The organic part, which consisted of agricultural waste material, mainly fruit and vegetable waste, was crushed and milled using blender. The sludge that produced from milling process was then used as a substrate for mixed culture microorganism as a raw material to produce biohydrogen. As much as 1.2 kg.day-1 of sludge (4% of total solid) was fed into bioreactor that had a capacity of 30L. Experiment was done under anaerobic fermentation using bacteria mixture culture that maintained at pH in the range of 5.6-6.5 and temperature of 25-30oC on semi-continuous mode. Parameters of analysis include pH, temperature, total solid (TS), organic total solid (OTS), total gas production, and hydrogen gas production. The results showed that from 4% of substrate resulted 897.86 L of total gas, which contained 660.74 L (73.59%) of hydrogen gas. The rate of hydrogen production in this study was 11,063 mol.L-1.h-1.

  13. Passive immunisation, an old idea revisited: Basic principles and application to modern animal production systems.

    Science.gov (United States)

    Hedegaard, Chris J; Heegaard, Peter M H

    2016-06-01

    Immunisation by administration of antibodies (immunoglobulins) has been known for more than one hundred years as a very efficient means of obtaining immediate, short-lived protection against infection and/or against the disease-causing effects of toxins from microbial pathogens and from other sources. Thus, due to its rapid action, passive immunisation is often used to treat disease caused by infection and/or toxin exposure. However immunoglobulins may also be administered prior to exposure to infection and/or toxin, although they will not provide long-lasting protection as is seen with active immunisation (vaccination) in which an immunological memory is established by controlled exposure of the host to the pathogen in question. With multi-factorial infectious diseases in production animals, especially those that have proven hard to control by vaccination, the potential of passive immunisation remains big. This review highlights a number of examples on the use of passive immunisation for the control of infectious disease in the modern production of a range of animals, including pigs, cattle, sheep, goat, poultry and fish. Special emphasis is given on the enablement of passive immunisation strategies in these production systems through low cost and ease of use as well as on the sources, composition and purity of immunoglobulin preparations used and their benefits as compared to current measures, including vaccination (also comprising maternal vaccination), antibiotics and feed additives such as spray-dried plasma. It is concluded that provided highly efficient, relatively low-price immunoglobulin products are available, passive immunisation has a clear role in the modern animal production sector as a means of controlling infectious diseases, importantly with a very low risk of causing development of bacterial resistance, thus constituting a real and widely applicable alternative to antibiotics.

  14. Determination for β-delayed fission probability of 230Ac

    Institute of Scientific and Technical Information of China (English)

    袁双贵; 杨维凡; 徐岩冰; 肖永厚; 罗亦孝

    2002-01-01

    The 230Ra has been produced via 232Th-2p reaction induced by 60 MeV/u 18O ion irradia-tion of natural thorium. The radium was radiochemically separated from the mixture of thorium andreaction products. Thin Ra sources in which 230Ac was got through 230Ra β- → 230Ac were pre-pared for observing fission fragments from β-delayed fission of 230Ac. The sources were exposedto the mica fission track detectors and measured by the HPGe γ detector. The precursor 230Ac wasidentified by means of observed two fission events as well as γ spectra, and the β-delayed fissionprobability of 230Ac was obtained to be (1.19±0.85) × 10-8.

  15. Passive immunisation, an old idea revisited: Basic principles and application to modern animal production systems

    DEFF Research Database (Denmark)

    Hedegaard, Chris Juul; Heegaard, Peter M. H.

    2016-01-01

    Immunisation by administration of antibodies (immunoglobulins) has been known for more than one hundred years as a very efficient means of obtaining immediate, short-lived protection against infection and/or against the disease-causing effects of toxins from microbial pathogens and from other sou...... development of bacterial resistance, thus constituting a real and widely applicable alternative to antibiotics....... remains big. This review highlights a number of examples on the use of passive immunisation for the control of infectious disease in the modern production of a range of animals, including pigs, cattle, sheep, goat, poultry and fish. Special emphasis is given on the enablement of passive immunisation...... strategies in these production systems through low cost and ease of use as well as on the sources, composition and purity of immunoglobulin preparations used and their benefits as compared to current measures, including vaccination (also comprising maternal vaccination), antibiotics and feed additives...

  16. Axisymmetric Magnetic Mirror Fusion-Fission Hybrid

    Energy Technology Data Exchange (ETDEWEB)

    Moir, R. W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Martovetsky, N. N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Molvik, A. W. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ryutov, D. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Simonen, T. C. [Univ. of California, Berkeley, CA (United States)

    2011-05-13

    The achieved performance of the gas dynamic trap version of magnetic mirrors and today’s technology we believe are sufficient with modest further efforts for a neutron source for material testing (Q=Pfusion/Pinput~0.1). The performance needed for commercial power production requires considerable further advances to achieve the necessary high Q>>10. An early application of the mirror, requiring intermediate performance and intermediate values of Q~1 are the hybrid applications. The Axisymmetric Mirror has a number of attractive features as a driver for a fusion-fission hybrid system: geometrical simplicity, inherently steady-state operation, and the presence of the natural divertors in the form of end tanks. This level of physics performance has the virtue of low risk and only modest R&D needed and its simplicity promises economy advantages. Operation at Q~1 allows for relatively low electron temperatures, in the range of 4 keV, for the DT injection energy ~ 80 keV. A simple mirror with the plasma diameter of 1 m and mirror-to-mirror length of 35 m is discussed. Simple circular superconducting coils are based on today’s technology. The positive ion neutral beams are similar to existing units but designed for steady state. A brief qualitative discussion of three groups of physics issues is presented: axial heat loss, MHD stability in the axisymmetric geometry, microstability of sloshing ions. Burning fission reactor wastes by fissioning actinides (transuranics: Pu, Np, Am, Cm, .. or just minor actinides: Np, Am, Cm, …) in the hybrid will multiply fusion’s energy by a factor of ~10 or more and diminish the Q needed to less than 1 to overcome the cost of recirculating power for good economics. The economic value of destroying actinides by fissioning is rather low based on either the cost of long-term storage or even deep geologic disposal so most of the revenues of hybrids will come from electrical power. Hybrids that obtain revenues from

  17. A natural connection on a basic class of Riemannian product manifolds

    CERN Document Server

    Gribacheva, Dobrinka

    2011-01-01

    A Riemannian manifold M with an integrable almost product structure P is called a Riemannian product manifold. Our investigations are on the manifolds (M; P; g) of the largest class of Riemannian product manifolds, which is closed with respect to the group of conformal transformations of the metric g. This class is an analogue of the class of locally conformal Kahler manifolds in almost Hermitian geometry. In the present paper we study a natural connection D on (M; P; g) (i.e. DP = Dg = 0). We find necessary and suffcient conditions the curvature tensor of D to have properties similar to the Kahler tensor in Hermitian geometry. We pay attention to the case when D has a parallel torsion.We establish that the Weyl tensors for the connection D and the Levi-Civita connection coincide as well as the invariance of the curvature tensor of D with respect to the usual conformal transformation. We consider the case when D is a at connection. We construct an example of the considered manifold by a Lie group where D is a...

  18. Fission product release model for failed plate-type fuel element and storage under water; Modelo para liberacao de produtos de fissao por placa combustivel falhada e armazenada sob agua

    Energy Technology Data Exchange (ETDEWEB)

    Terremoto, L.A.A.; Zeituni, C.A.; Silva, J.E.R. da; Castanheira, M.; Lucki, G.; Silva, A.T. e; Teodoro, C.A.; Damy, M. de A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Centro de Engenharia Nuclear]. E-mail: laaterre@ipen.br

    2005-07-01

    Plate-type fuel elements burned-up inside the core of nuclear research reactors are stored mainly under deionized water of storage pools. When cladding failure occurs in such elements, radioactive fission products are released into the storage pool water. This work proposes a model to describe the release mechanism considering the diffusion through a postulated small cylindrical failure. As a consequence, an analytical expression is obtained for the activity released into the water as a function of the total storage time of a failed fuel plate. The proposed model reproduces the linear increasing of {sup 137}Cs specific activity observed in sipping tests already performed on failed plate-type fuel elements. (author)

  19. Fission modes in charged-particle induced fission

    Energy Technology Data Exchange (ETDEWEB)

    Matthies, A.; Kotte, R.; Seidel, W.; Stary, F.; Wohlfarth, D. (Zentralinstitut fuer Kernforschung, Rossendorf bei Dresden (German Democratic Republic))

    1990-12-01

    The population of the three fission modes predicted by Brosa's multi-channel fission model for the uranium region was studied in different fissioning systems. They were produced bombarding {sup 232}Th and {sup 238}U targets by light charged particles with energies slightly above the Coulomb barrier. Though the maximum excitation energy of the compound nucleus amounted to about 22 MeV, the influences of various spherical and deformed nuclear shells on the mass and total kinetic energy distributions of fission fragments are still pronounced. The larger variances of the total kinetic energy distributions compared to those of thermal neutron induced fission were explained by temperature dependent fluctuations of the amount and velocity of alteration of the scission point elongation of the fissioning system. From the ratio of these variances the portion of the potential energy dissipated among intrinsic degrees of freedom before scission was deduced for the different fission channels. It was found that the excitation remaining after pre-scission neutron emission is mainly transferred into intrinsic heat and less into pre-scission kinetic energy. (orig.).

  20. Transfusion audit of blood products using the World Health Organization Basic Information Sheet in Qazvin, Islamic Republic of Iran.

    Science.gov (United States)

    Sheikholeslami, H; Kani, C; Fallah-Abed, P; Lalooha, F; Mohammadi, N

    2012-12-04

    We assessed the practicality of using the transfusion Basic Information Sheet (BIS) for data collection, to determine the overall adequacy of physician documentation of blood product transfusion, and to make an audit of the appropriateness of blood product transfusion. The transfusion process and clinical indications for transfusions administered to adult hospitalized patients in 3 tertiary care teaching hospitals in Qazvin were prospectively reviewed. Adequate documentation was achieved in 62.6% of all transfusion episodes, range 41%-73%, depending on the medical specialty; 15.7% of red blood cells and whole blood requests, 40.8% of platelet requests and 34.1% of fresh frozen plasma requests were inappropriate. BIS-based information along with data collection can be used to provide feedback regarding the effectiveness of and compliance with local and national transfusion guidelines.

  1. THE CONSUMPTION OF BASIC PRODUCTION MEANS IN POLISH AGRICULTURE IN RESPECT TO SUSTAINABLE DEVELOPMENT OF AGRICULTURE AND RURAL AREAS

    Directory of Open Access Journals (Sweden)

    Wacław Jarecki

    2014-10-01

    The plant protection by pesticides is increasing in Poland and the established trend rate took into account years 2005-2011. In the period 2002-2004 statistics did not present the full range of crop protection measures authorized for sale and consumption. In contrast the consumption of qualified seeds of basic grains and seed potatoes considerably decreased in Polish agriculture. Only for triticale it was noticed that the trend rate of qualified seeds was increasing. So the farmers should be more widely informed about the advantages of the exchange of seed grain for qualified grains. It will facilitate the quicker implementation of variety progress to agricultural production and adverse changes slowdown agricultural production.

  2. Basic investigation into the production of oxygen in a solid electrolyte process

    Science.gov (United States)

    Richter, R.

    1981-01-01

    Mission analyses indicated that by extracting oxygen from the Martian atmosphere, which consists primarily of carbon dioxide, the launch mass of a spacecraft can be reduced by such an amount that samples from the planet can be returned to earth. The solid electrolyte process for producing O2 from CO2 was investigated. A model of the thermodynamic and electrochemical processes in the electrolyte cell was postulated, thereby establishing the parameters influencing the effectiveness and efficiency of an in situ O2 production system. The major operating parameters were investigated over a wide range of temperature and pressure. Operating limits imposed by the solid electrolyte material, 8% yttria stabilized zirconia, were determined as a function of the operating temperature.

  3. Proton-induced fission at 190 MeV of W-nat, Au-197, Pb-nat, Pb-208, and Th-232

    NARCIS (Netherlands)

    Duijvestijn, MC; Koning, AJ; Beijers, JPM; Gastal, M; van Klinken, J; Ostendorf, RW

    1999-01-01

    Proton-induced fission at 190 MeV of W-nat, Au-197, Pb-nat, Pb-208, and Th-232 is studied by means of an innovative method based on activation analysis. The fission-product mass distribution is reconstructed from the fission-product yields, which are obtained from off-line observed gamma-ray spectra

  4. The spectroscopy of fission fragments

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, W.R. [Department of Physics and Astronomy, University of Manchester, Manchester, M13 9PL (United Kingdom); Collaboration: La Direction des Sciences de la Matiere du CEA (FR); Le Fonds National de la Recherche Scientifique de Belgique (BE)

    1998-12-31

    High-resolution measurements on {gamma} rays from fission fragments have provided a rich source of information, unobtainable at the moment in any other way, on the spectroscopy of neutron-rich nuclei. In recent years important data have been obtained on the yrast- and near yrast-structure of neutron-rich fission fragments. We discuss the scope of measurements which can be made on prompt gamma rays from secondary fission fragments, the techniques used in the experiments and some results recently obtained. (author) 24 refs., 8 figs., 1 tab.

  5. Intrinsic energy partition in fission

    Directory of Open Access Journals (Sweden)

    Mirea M.

    2013-03-01

    Full Text Available The intrinsic energy partition between two complementary fission fragments is investigated microscopically. The intrinsic excitation energy of fission fragments is dynamically evaluated in terms of the time-dependent pairing equations. These equations are corroborated with two conditions. One of them fixes the number of particles and the other separates the pairing active spaces associated to the two fragments in the vicinity of the scission configuration. The excitation energy in a wide distribution of fission fragments is calculated for the 234U parent nucleus.

  6. {sup 7}Be radioactive beam production at CIRCE and its utilization in basic and applied physics

    Energy Technology Data Exchange (ETDEWEB)

    Limata, Benedicta Normanna [Sezione di Napoli, INFN, Ed. G, Via Cintia, Napoli 80126 (Italy)], E-mail: limata@na.infn.it; Gialanella, Lucio; Leva, Antonino Di [Sezione di Napoli, INFN, Ed. G, Via Cintia, Napoli 80126 (Italy); Cesare, Nicola De [Sezione di Napoli, INFN, Ed. G, Via Cintia, Napoli 80126 (Italy); Dipartimento di Scienze della Vita, II Universita di Napoli, Via Vivaldi 43, Caserta 81100 (Italy); D' Onofrio, Antonio [Sezione di Napoli, INFN, Ed. G, Via Cintia, Napoli 80126 (Italy); Dipartimento di Scienze Ambientali, II Universita di Napoli, Via Vivaldi 43, Caserta 81100 (Italy); Gyurky, G. [ATOMKI, POB 51, Debrecen H-4001 (Hungary); Rolfs, Claus [Institut fuer Experimentalphysik III, RuhrUniversitaet, Universitatetstrasse 150, Bochum D-44780 (Germany); Romano, Mario [Sezione di Napoli, INFN, Ed. G, Via Cintia, Napoli 80126 (Italy); Dipartimento di Scienze Fisiche, Universita di Napoli Federico II, Ed. G Via Cintia, Napoli 80126 (Italy); Rogalla, Detlef [Institut fuer Experimentalphysik III, RuhrUniversitaet, Universitatetstrasse 150, Bochum D-44780 (Germany); Rossi, Cesare; Russo, Michele [DIME, Universita di Napoli Federico II, Via Claudio, Napoli 80126 (Italy); Somorjai, Endre [ATOMKI, POB 51, Debrecen H-4001 (Hungary); Terrasi, Filippo [Sezione di Napoli, INFN, Ed. G, Via Cintia, Napoli 80126 (Italy); Dipartimento di Scienze Ambientali, II Universita di Napoli, Via Vivaldi 43, Caserta 81100 (Italy)

    2008-05-15

    A pure {sup 7}Be beam with an energy E = 1-8 MeV is available for nuclear and applied physics at the 3 MV Pelletron tandem accelerator CIRCE in Caserta. The beam is produced using an offline technique. Typical analyzed beam intensities are about 2 ppA, using cathodes with an activity of the order of 200 MBq. The {sup 7}Be implantation has been used for both fundamental nuclear physics and applied physics. In particular, different metals have been implanted with {sup 7}Be in order to study the influence of the chemical composition and of the number of quasi-free electrons of the host material on the {sup 7}Be half-life. In the field of applied physics, the {sup 7}Be implantation turns out to be very interesting for wear measurement. In fact, in this case {sup 7}Be is used as a depth-sensitive tracer. The continuous detection of the sample activity during the wear allows a high sensitivity measurement of wearing speed. The {sup 7}Be beam production at CIRCE, the implantation procedure and the results obtained from the {sup 7}Be half-life measurements and the wear characterization of implanted steel samples are described.

  7. Product, not process! Explaining a basic concept in agricultural biotechnologies and food safety.

    Science.gov (United States)

    Tagliabue, Giovanni

    2017-12-01

    Most life scientists have relentlessly recommended any evaluative approach of agri-food products to be based on examination of the phenotype, i.e. the actual characteristics of the food, feed and fiber varieties: the effects of any new cultivar (or micro-organism, animal) on our health are not dependent on the process(es), the techniques used to obtain it.The so-called "genetically modified organisms" ("GMOs"), on the other hand, are commonly framed as a group with special properties - most frequently seen as dubious, or even harmful.Some social scientists still believe that considering the process is a correct background for science-based understanding and regulation. To show that such an approach is utterly wrong, and to invite scientists, teachers and science communicators to explain this mistake to students, policy-makers and the public at large, we imagined a dialogue between a social scientist, who has a positive opinion about a certain weight that a process-based orientation should have in the risk assessment, and a few experts who offer plenty of arguments against that view. The discussion focuses on new food safety.

  8. Nucleon localization and fragment formation in nuclear fission

    Science.gov (United States)

    Zhang, C. L.; Schuetrumpf, B.; Nazarewicz, W.

    2016-12-01

    Background: An electron localization measure was originally introduced to characterize chemical bond structures in molecules. Recently, a nucleon localization based on Hartree-Fock densities has been introduced to investigate α -cluster structures in light nuclei. Compared to the local nucleonic densities, the nucleon localization function has been shown to be an excellent indicator of shell effects and cluster correlations. Purpose: Using the spatial nucleon localization measure, we investigate the emergence of fragments in fissioning heavy nuclei. Methods: To illustrate basic concepts of nucleon localization, we employ the self-consistent energy density functional method with a quantified energy density functional optimized for fission studies. Results: We study the particle densities and spatial nucleon localization distributions along the fission pathways of 264Fm, 232Th, and 240Pu. We demonstrate that the fission fragments are formed fairly early in the evolution, well before scission. We illustrate the usefulness of the localization measure by showing how the hyperdeformed state of 232Th can be understood in terms of a quasimolecular state made of 132Sn and 100Zr fragments. Conclusions: Compared to nucleonic distributions, the nucleon localization function more effectively quantifies nucleonic clustering: its characteristic oscillating pattern, traced back to shell effects, is a clear fingerprint of cluster/fragment configurations. This is of particular interest for studies of fragment formation and fragment identification in fissioning nuclei.

  9. Neutron threshold activation detectors (TAD) for the detection of fissions

    Science.gov (United States)

    Gozani, Tsahi; Stevenson, John; King, Michael J.

    2011-10-01

    , called Threshold Activation Detection (TAD), is to utilize appropriate substances that can be selectively activated by the fission neutrons and not by the source radiation and then measure the radioactively decaying activation products (typically beta and gamma rays) well after the source pulse. The activation material should possess certain properties: a suitable half-life of the order of seconds; an energy threshold below which the numerous source neutrons will not activate it (e.g., 3 MeV); easily detectable activation products (typically >1 MeV beta and gamma rays) and have a usable cross-section for the selected reaction. Ideally the substance would be a part of the scintillator. There are several good material candidates for the TAD, including fluorine, which is a major constituent of available scintillators such as BaF 2, CaF 2 and hydrogen free liquid fluorocarbon. Thus the fluorine activation products, in particular the beta particles, can be measured with a very high efficiency in the detector. The principles, applications and experimental results obtained with the fluorine based TAD are discussed.

  10. [Ways of inserting physicians into the healthcare production process: case of study of basic healthcare units in Belo Horizonte, Brazil].

    Science.gov (United States)

    Gariglio, Maria Terezinha; Radicchi, Antônio Leite Alves

    2008-01-01

    The main purpose of this paper is to describe and analyze the ways of inserting physicians into the health production process. This subject is justified by a belief that that this way of working may be a problem but at the same time may well be the key to implementing healthcare models that are ethically and politically committed to the lives of public health system users. Initially, the problem is presented through the construction of an archetype physician and his historical and social and cultural conditioning factors, taking the work processes of physicians at Basic Healthcare Units in Belo Horizonte as an example that is built up through interviews and participative observations. Some possibilities for intervention are indicated through the introduction of new concepts and technologies that could transform the work of these practitioners in ways that would build up links with more responsibility for the care and lives of users of public healthcare services.

  11. FREYA-a new Monte Carlo code for improved modeling of fission chains

    Energy Technology Data Exchange (ETDEWEB)

    Hagmann, C A; Randrup, J; Vogt, R L

    2012-06-12

    A new simulation capability for modeling of individual fission events and chains and the transport of fission products in materials is presented. FREYA ( Fission Yield Event Yield Algorithm ) is a Monte Carlo code for generating fission events providing correlated kinematic information for prompt neutrons, gammas, and fragments. As a standalone code, FREYA calculates quantities such as multiplicity-energy, angular, and gamma-neutron energy sharing correlations. To study materials with multiplication, shielding effects, and detectors, we have integrated FREYA into the general purpose Monte Carlo code MCNP. This new tool will allow more accurate modeling of detector responses including correlations and the development of SNM detectors with increased sensitivity.

  12. Dependence of Fission-Fragment Properties On Excitation Energy For Neutron-Rich Actinides

    Directory of Open Access Journals (Sweden)

    Ramos D.

    2016-01-01

    Isotopic fission yields of 250Cf, 244Cm, 240Pu, 239Np and 238U are presented in this work. With this information, the average number of neutrons as a function of the atomic number of the fragments is calculated, which reflects the impact of nuclear structure around Z=50, N=80 on the production of fission fragments. The characteristics of the Super Long, Standard I, Standard II, and Standard III fission channels were extracted from fits of the fragment yields for different ranges of excitation energy. The position and contribution of the fission channels as function of excitation energy are presented.

  13. Feed-derived volatile basic nitrogen increases reactive oxygen species production of blood leukocytes in lactating dairy cows.

    Science.gov (United States)

    Tsunoda, Ei; Gross, Josef J; Kawashima, Chiho; Bruckmaier, Rupert M; Kida, Katsuya; Miyamoto, Akio

    2017-01-01

    The present study investigated over 9 months the changes of fermentative quality of total mixed rations (TMR) containing grass silage (GS) as a major component, associated with changes in the volatile basic nitrogen (VBN) levels in an experimental dairy farm. Effects of VBN levels in TMR on metabolic parameters, reactive oxygen species (ROS) production by blood polymorphonuclear leukocytes (PMNs) and conception rates for dairy cows were analyzed. According to VBN levels in TMR during survey periods, three distinct phases were identified; phase A with low VBN; phase B with high VBN; and phase C with mid-VBN. Metabolic parameters in blood were all within normal range. However, during phases B and C, nitrogen metabolic indices such as blood urea nitrogen and milk urea nitrogen showed higher levels compared to those in phase A, and a simultaneous increase in ROS production by blood PMNs and the load on hepatic function in metabolic parameters was observed in the cows with a lower conception rate. This suggests that feeding TMR with elevated VBN levels due to poor fermented GS results in stimulation of ROS production by PMNs by ammonia, and negatively affects metabolism and reproductive performance in lactating dairy cow.

  14. Advanced Space Fission Propulsion Systems

    Science.gov (United States)

    Houts, Michael G.; Borowski, Stanley K.

    2010-01-01

    Fission has been considered for in-space propulsion since the 1940s. Nuclear Thermal Propulsion (NTP) systems underwent extensive development from 1955-1973, completing 20 full power ground tests and achieving specific impulses nearly twice that of the best chemical propulsion systems. Space fission power systems (which may eventually enable Nuclear Electric Propulsion) have been flown in space by both the United States and the Former Soviet Union. Fission is the most developed and understood of the nuclear propulsion options (e.g. fission, fusion, antimatter, etc.), and fission has enjoyed tremendous terrestrial success for nearly 7 decades. Current space nuclear research and technology efforts are focused on devising and developing first generation systems that are safe, reliable and affordable. For propulsion, the focus is on nuclear thermal rockets that build on technologies and systems developed and tested under the Rover/NERVA and related programs from the Apollo era. NTP Affordability is achieved through use of previously developed fuels and materials, modern analytical techniques and test strategies, and development of a small engine for ground and flight technology demonstration. Initial NTP systems will be capable of achieving an Isp of 900 s at a relatively high thrust-to-weight ratio. The development and use of first generation space fission power and propulsion systems will provide new, game changing capabilities for NASA. In addition, development and use of these systems will provide the foundation for developing extremely advanced power and propulsion systems capable of routinely and affordably accessing any point in the solar system. The energy density of fissile fuel (8 x 10(exp 13) Joules/kg) is more than adequate for enabling extensive exploration and utilization of the solar system. For space fission propulsion systems, the key is converting the virtually unlimited energy of fission into thrust at the desired specific impulse and thrust

  15. Fission hindrance and nuclear viscosity

    Indian Academy of Sciences (India)

    Indranil Mazumdar

    2015-08-01

    We discuss the role of nuclear viscosity in hindering the fission of heavy nuclei as observed in the experimental measurements of GDR -ray spectra from the fissioning nuclei. We review a set of experiments carried out and reported by us previously [see Dioszegi et al, Phys. Rev. C 61, 024613 (2000); Shaw et al, Phys. Rev. C 61, 044612 (2000)] and argue that the nuclear viscosity parameter has no apparent dependence on temperature. However, it may depend upon the deformation of the nucleus.

  16. New fission fragment distributions and r-process origin of the rare-earth elements

    CERN Document Server

    Goriely, S; Lemaitre, J -F; Panebianco, S; Dubray, N; Hilaire, S; Bauswein, A; Janka, H -Thomas

    2013-01-01

    Neutron star (NS) merger ejecta offer a viable site for the production of heavy r-process elements with nuclear mass numbers A > 140. The crucial role of fission recycling is responsible for the robustness of this site against many astrophysical uncertainties, but calculations sensitively depend on nuclear physics. In particular the fission fragment yields determine the creation of 110 140.

  17. Energy dependence of 238U fission yields investigated in inverse kinematics

    Directory of Open Access Journals (Sweden)

    Veselsky M.

    2010-03-01

    Full Text Available The production cross sections of neutron-rich fission residues produced in reactions induced by a 238U beam impinging onto Pb and Be targets were investigated at the Fragment Separator (FRS at GSI using the inverse kinematic technique. These data allowed us to discuss the optimum energies in fission for producing the most neutron-rich residues.

  18. Basic Soil Productivity of Spring Maize in Black Soil Under Long-Term Fertilization Based on DSSAT Model

    Institute of Scientific and Technical Information of China (English)

    ZHA Yan; WU Xue-ping; HE Xin-hua; ZHANG Hui-min; GONG Fu-fei; CAI Dian-xiong; ZHU Ping; GAO Hong-jun

    2014-01-01

    Increasing basic farmland soil productivity has signiifcance in reducing fertilizer application and maintaining high yield of crops. In this study, we deifned that the basic soil productivity (BSP) is the production capacity of a farmland soil with its own physical and chemical properties for a speciifc crop season under local environment and ifeld management. Based on 22-yr (1990-2011) long-term experimental data on black soil (Typic hapludoll) in Gongzhuling, Jilin Province, Northeast China, the decision support system for an agro-technology transfer (DSSAT)-CERES-Maize model was applied to simulate the yield by BSP of spring maize (Zea mays L.) to examine the effects of long-term fertilization on changes of BSP and explore the mechanisms of BSP increasing. Five treatments were examined:(1) no-fertilization control (control);(2) chemical nitrogen, phosphorus, and potassium (NPK); (3) NPK plus farmyard manure (NPKM); (4) 1.5 time of NPKM (1.5NPKM) and (5) NPK plus straw (NPKS). Results showed that after 22-yr fertilization, the yield by BSP of spring maize signiifcantly increased 78.0, 101.2, and 69.4% under the NPKM, 1.5NPKM and NPKS, respectively, compared to the initial value (in 1992), but not signiifcant under NPK (26.9%increase) and the control (8.9%decrease). The contribution percentage of BSP showed a signiifcant rising trend (PNPKM>NPK≈NPKS, indicating that organic manure combined with chemical fertilizers (1.5NPKM and NPKM) could more effectively increase BSP compared with the inorganic fertilizer application alone (NPK) in the black soil. This study showed that soil organic matter (SOM) was the key factor among various fertility factors that could affect BSP in the black soil, and total N, total P and/or available P also played important role in BSP increasing. Compared with the chemical fertilization, a balanced chemical plus manure or straw fertilization (NPKM or NPKS) not only increased the concentrations of soil nutrient, but also improved the

  19. Long-term organic and inorganic fertilizations enhanced basic soil productivity in a lfuvo-aquic soil

    Institute of Scientific and Technical Information of China (English)

    ZHA Yan; WU Xue-ping; GONG Fu-fei; XU Ming-gang; ZHANG Hui-min; CHEN Li-ming; HUANG Shao-min; CAI Dian-xiong

    2015-01-01

    The improvement of soil productivity depends on a rational input of water and nutrients, optimal ifeld management, and the increase of basic soil productivity (BSP). In this study, BSP is deifned as the productive capacity of a farmland soil with its own physical and chemical properties for a speciifc crop season under local ifeld management. Based on 19-yr data of the long-term agronomic experiments (1989–2008) on a lfuvo-aquic soil in Zhengzhou, Henan Province, China, the decision support system for agrotechnology transfer (DSSAT ver. 4.0) crop growth model was used to simulate yields by BSP of winter wheat (Triticum aestiviumL.) and summer maize (Zea maysL.) to examine the relationship between BSP and soil organic carbon (SOC) under long-term fertilization. Five treatments were included: (1) no fertilization (control), (2) nitrogen, phosphorus and potassium fertilizers (NPK), (3) NPK plus manure (NPKM), (4) 1.5 times of NPKM (1.5NPKM), and (5) NPK plus straw (NPKS). After 19 yr of treatments, the SOC stock increased 16.7, 44.2, 69.9, and 25.2% under the NPK, NPKM, 1.5NPKM, and NPKS, respectively, compared to the initial value. Among various nutrient factors affecting contribution per-centage of BSP to winter wheat and summer maize, SOC was a major affecting factor for BSP in the lfuvo-aquic soil. There were signiifcant positive correlations between SOC stock and yields by BSP of winter wheat and summer maize (P<0.01), and yields by BSP of winter wheat and summer maize increased 154 and 132 kg ha–1 when SOC stock increased 1 t C ha–1. Thus, increased SOC accumulation is a crucial way for increasing BSP in lfuvo-aquic soil.The manure or straw combined application with chemical fertilizers signiifcantly enhanced BSP compared to the application of chemical fertilizers alone.

  20. Event-by-event study of neutron observables in spontaneous and thermal fission

    Energy Technology Data Exchange (ETDEWEB)

    Vogt, R; Randrup, J

    2011-09-14

    The event-by-event fission model FREYA is extended to spontaneous fission of actinides and a variety of neutron observables are studied for spontaneous fission and fission induced by thermal neutrons with a view towards possible applications for SNM detection. We have shown that event-by-event models of fission, such as FREYA, provide a powerful tool for studying fission neutron correlations. Our results demonstrate that these correlations are significant and exhibit a dependence on the fissioning nucleus. Since our method is phenomenological in nature, good input data are especially important. Some of the measurements employed in FREYA are rather old and statistics limited. It would be useful to repeat some of these studies with modern detector techniques. In addition, most experiments made to date have not made simultaneous measurements of the fission products and the prompt observables, such as neutron and photons. Such data, while obviously more challenging to obtain, would be valuable for achieving a more complete understanding of the fission process.

  1. Beta-delayed fission probabilities of transfermium nuclei, involved in the r-process

    Science.gov (United States)

    Panov, I.; Lutostansky, Yu; Thielemann, F.-K.

    2016-01-01

    For the nucleosynthesis of heavy and superheavy nuclei fission becomes very important when the r-process runs in a very high neutron density environment. In part, fission is responsible for the formation of heavy nuclei due to the inclusion of fission products as new seed nuclei (fission cycling). More than that, beta-delayed fission, along with spontaneous fission, is responsible in the late stages of the r-process for the suppression of superheavy element yields. For beta-delayed fission probability calculations a model description of the beta-strength- functions is required. Extended theoretical predictions for astro-physical applications were provided long ago, and new predictions also for superheavy nuclei with uptodate nuclear input are needed. For the further extension of data to heavier transactinides the models of strength- functions should be modified, taking into account more complicated level schemes. In our present calculations the strength-function model is based on the quasi-particle approximation of Finite Fermi Systems Theory. The probabilities of beta-delayed fission and beta-delayed neutron emission are calculated for some transfermium neutron-rich nuclei, and the influence of beta-delayed fission upon superheavy element formation is discussed.

  2. Recoil-alpha-fission and recoil-alpha-alpha-fission events observed in the reaction Ca-48 + Am-243

    CERN Document Server

    Forsberg, U; Andersson, L -L; Di Nitto, A; Düllmann, Ch E; Gates, J M; Golubev, P; Gregorich, K E; Gross, C J; Herzberg, R -D; Hessberger, F P; Khuyagbaatar, J; Kratz, J V; Rykaczewski, K; Sarmiento, L G; Schädel, M; Yakushev, A; Åberg, S; Ackermann, D; Block, M; Brand, H; Carlsson, B G; Cox, D; Derkx, X; Dobaczewski, J; Eberhardt, K; Even, J; Fahlander, C; Gerl, J; Jäger, E; Kindler, B; Krier, J; Kojouharov, I; Kurz, N; Lommel, B; Mistry, A; Mokry, C; Nazarewicz, W; Nitsche, H; Omtvedt, J P; Papadakis, P; Ragnarsson, I; Runke, J; Schaffner, H; Schausten, B; Shi, Y; Thörle-Pospiech, P; Torres, T; Traut, T; Trautmann, N; Türler, A; Ward, A; Ward, D E; Wiehl, N

    2015-01-01

    Products of the fusion-evaporation reaction Ca-48 + Am-243 were studied with the TASISpec set-up at the gas-filled separator TASCA at the GSI Helmholtzzentrum f\\"ur Schwerionenforschung. Amongst the detected thirty correlated alpha-decay chains associated with the production of element Z=115, two recoil-alpha-fission and five recoil-alpha-alpha-fission events were observed. The latter are similar to four such events reported from experiments performed at the Dubna gas-filled separator. Contrary to their interpretation, we propose an alternative view, namely to assign eight of these eleven decay chains of recoil-alpha(-alpha)-fission type to start from the 3n-evaporation channel 115-288. The other three decay chains remain viable candidates for the 2n-evaporation channel 115-289.

  3. Assessment of fissionable material behaviour in fission chambers

    Energy Technology Data Exchange (ETDEWEB)

    Cabellos, O., E-mail: oscar.cabellos@upm.e [Instituto de Fusion Nuclear, Universidad Politecnica de Madrid, 28006 Madrid (Spain); Department of Nuclear Engineering, Universidad Politecnica de Madrid, 28006 Madrid (Spain); Fernandez, P. [Department of Nuclear Engineering, Universidad Politecnica de Madrid, 28006 Madrid (Spain); Rapisarda, D. [Laboratorio Nacional de Fusion, EURATOM-CIEMAT, 28040 Madrid (Spain); Garcia-Herranz, N. [Instituto de Fusion Nuclear, Universidad Politecnica de Madrid, 28006 Madrid (Spain); Department of Nuclear Engineering, Universidad Politecnica de Madrid, 28006 Madrid (Spain)

    2010-06-21

    A comprehensive study is performed in order to assess the pertinence of fission chambers coated with different fissile materials for high neutron flux detection. Three neutron scenarios are proposed to study the fast component of a high neutron flux: (i) high neutron flux with a significant thermal contribution such as BR2, (ii) DEMO magnetic fusion reactor, and (iii) IFMIF high flux test module. In this study, the inventory code ACAB is used to analyze the following questions: (i) impact of different deposits in fission chambers; (ii) effect of the irradiation time/burn-up on the concentration; (iii) impact of activation cross-section uncertainties on the composition of the deposit for all the range of burn-up/irradiation neutron fluences of interest. The complete set of nuclear data (decay, fission yield, activation cross-sections, and uncertainties) provided in the EAF2007 data library are used for this evaluation.

  4. Fission gas in thoria

    Science.gov (United States)

    Kuganathan, Navaratnarajah; Ghosh, Partha S.; Galvin, Conor O. T.; Arya, Ashok K.; Dutta, Bijon K.; Dey, Gautam K.; Grimes, Robin W.

    2017-03-01

    The fission gases Xe and Kr, formed during normal reactor operation, are known to degrade fuel performance, particularly at high burn-up. Using first-principles density functional theory together with a dispersion correction (DFT + D), in ThO2 we calculate the energetics of neutral and charged point defects, the di-vacancy (DV), different neutral tri-vacancies (NTV), the charged tetravacancy (CTV) defect cluster geometries and their interaction with Xe and Kr. The most favourable incorporation point defect site for Xe or Kr in defective ThO2 is the fully charged thorium vacancy. The lowest energy NTV in larger supercells of ThO2 is NTV3, however, a single Xe atom is most stable when accommodated within a NTV1. The di-vacancy (DV) is a significantly less favoured incorporation site than the NTV1 but the CTV offers about the same incorporation energy. Incorporation of a second gas atom in a NTV is a high energy process and more unfavourable than accommodation within an existing Th vacancy. The bi-NTV (BNTV) cluster geometry studied will accommodate one or two gas atoms with low incorporation energies but the addition of a third gas atom incurs a high energy penalty. The tri-NTV cluster (TNTV) forms a larger space which accommodates three gas atoms but again there is a penalty to accommodate a fourth gas atom. By considering the energy to form the defect sites, solution energies were generated showing that in ThO2-x the most favourable solution equilibrium site is the NTV1 while in ThO2 it is the DV.

  5. Nuclear fission and neutron-induced fission cross-sections

    CERN Document Server

    James, G D; Michaudon, A; Michaudon, A; Cierjacks, S W; Chrien, R E

    2013-01-01

    Nuclear Fission and Neutron-Induced Fission Cross-Sections is the first volume in a series on Neutron Physics and Nuclear Data in Science and Technology. This volume serves the purpose of providing a thorough description of the many facets of neutron physics in different fields of nuclear applications. This book also attempts to bridge the communication gap between experts involved in the experimental and theoretical studies of nuclear properties and those involved in the technological applications of nuclear data. This publication will be invaluable to those interested in studying nuclear fis

  6. Experimental approach to fission process of actinides

    Energy Technology Data Exchange (ETDEWEB)

    Baba, Hiroshi [Osaka Univ., Toyonaka (Japan). Faculty of Science

    1997-07-01

    From experimental views, it seems likely that the mechanism of nuclear fission process remains unsolved even after the Bohr and Weeler`s study in 1939. Especially, it is marked in respect of mass distribution in unsymmetric nuclear fission. The energy dependency of mass distribution can be explained with an assumption of 2-mode nuclear fission. Further, it was demonstrated that the symmetrical fission components and the unsymmetrical ones have different saddle and fission points. Thus, the presence of the 2-mode fission mechanism was confirmed. Here, transition in the nuclear fission mechanism and its cause were investigated here. As the cause of such transition, plausible four causes; a contribution of multiple-chance fission, disappearance of shell effects, beginning of fission following collective excitation due to GDR and nuclear phase transition were examined in the condition of excitation energy of 14.0 MeV. And it was suggested that the transition in the nuclear fission concerned might be related to phase transition. In addition, the mechanism of nuclear fission at a low energy and multi-mode hypothesis were examined by determination of the energy for thermal neutron fission ({sup 233,235}U and {sup 239}Pu) and spontaneous nuclear fission ({sup 252}Cf). (M.N.)

  7. Chemical states of fission products in irradiated (U{sub 0.3}Pu{sub 0.7})C{sub 1+x} fuel at high burn-ups

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, Renu [Fuel Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)]. E-mail: arenu@barc.gov.in; Venugopal, V. [Fuel Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2006-12-01

    The chemical states of fission products have been theoretically determined for the irradiated carbide fuel of Fast Breeder Test Reactor (FBTR) at Kalpakkam, India, at different burn-ups. The SOLGASMIX-PV computer code was used to determine the equilibrium chemical composition of the fuel. The system was assumed to be composed of a gaseous phase at one atmosphere pressure, and various solid phases. The distribution of elements in these phases and their chemical states at different temperatures were calculated as a function of burn-up. The FBTR fuel (U{sub 0.3}Pu{sub 0.7})C{sub 1+x}, was loaded with C/M values in the range, 1.03-1.06. The present calculations indicated that even for the lowest starting C/M of 1.03 in the FBTR fuel, the liquid metal phase of (U, Pu), should not appear at a burn-up as high as 150 GWd/t.

  8. Modelling and simulation the radioactive source-term of fission products in PWR type reactors; Modelagem e simulacao do termo-fonte radioativo de produtos de fissao em reatores nucleares do tipo PWR

    Energy Technology Data Exchange (ETDEWEB)

    Porfirio, Rogilson Nazare da Silva

    1996-07-01

    The source-term was defined with the purpose the quantify all radioactive nuclides released the nuclear reactor in the case of accidents. Nowadays the source-term is limited to the coolant of the primary circuit of reactors and may be measured or modelled with computer coders such as the TFP developed in this work. The calculational process is based on the linear chain techniques used in the CINDER-2 code. The TFP code considers forms of fission products release from the fuel pellet: Recoil, Knockout and Migration. The release from the gap to the coolant fluid is determined from the ratio between activity measured in the coolant and calculated activity in the gap. Considered the operational data of SURRY-1 reactor, the TFP code was run to obtain the source=term of this reactor. From the measured activities it was verified the reliability level of the model and the employed computational logic. The accuracy of the calculated quantities were compared to the measured data was considered satisfactory. (author)

  9. Current research and development activities on fission products and hydrogen risk after the accident at Fukushima Daiichi Nuclear Power Station

    Directory of Open Access Journals (Sweden)

    Takeshi Nishimura

    2015-02-01

    Full Text Available After the Fukushima Daiichi nuclear power plant (NPP accident, new regulatory requirements were enforced in July 2013 and a backfit was required for all existing nuclear power plants. It is required to take measures to prevent severe accidents and mitigate their radiological consequences. The Regulatory Standard and Research Department, Secretariat of Nuclear Regulation Authority (S/NRA/R has been conducting numerical studies and experimental studies on relevant severe accident phenomena and countermeasures. This article highlights fission product (FP release and hydrogen risk as two major areas. Relevant activities in the S/NRA/R are briefly introduced, as follows: 1. For FP release: Identifying the source terms and leak mechanisms is a key issue from the viewpoint of understanding the progression of accident phenomena and planning effective countermeasures that take into account vulnerabilities of containment under severe accident conditions. To resolve these issues, the activities focus on wet well venting, pool scrubbing, iodine chemistry (in-vessel and ex-vessel, containment failure mode, and treatment of radioactive liquid effluent. 2. For hydrogen risk: because of three incidents of hydrogen explosion in reactor buildings, a comprehensive reinforcement of the hydrogen risk management has been a high priority topic. Therefore, the activities in evaluation methods focus on hydrogen generation, hydrogen distribution, and hydrogen combustion.

  10. Search for Singlet Fission Chromophores

    Energy Technology Data Exchange (ETDEWEB)

    Havlas, Z.; Akdag, A.; Smith, M. B.; Dron, P.; Johnson, J. C.; Nozik, A. J.; Michl, J.

    2012-01-01

    Singlet fission, in which a singlet excited chromophore shares its energy with a ground-state neighbor and both end up in their triplet states, is of potential interest for solar cells. Only a handful of compounds, mostly alternant hydrocarbons, are known to perform efficiently. In view of the large number of conditions that a successful candidate for a practical cell has to meet, it appears desirable to extend the present list of high performers to additional classes of compounds. We have (i) identified design rules for new singlet fission chromophores and for their coupling to covalent dimers, (ii) synthesized them, and (iii) evaluated their performance as neat solids or covalent dimers.

  11. Spontaneous fission of superheavy nuclei

    Indian Academy of Sciences (India)

    R A Gherghescu; D N Poenaru

    2015-09-01

    The macroscopic–microscopic method is extended to calculate the deformation energy and penetrability for binary nuclear configurations typical for fission processes. The deformed two-centre shell model is used to obtain single-particle energy levels for the transition region of two partially overlapped daughter and emitted fragment nuclei. The macroscopic part is obtained using the Yukawa-plus-exponential potential. The microscopic shell and pairing corrections are obtained using the Strutinsky and BCS approaches and the cranking formulae yield the inertia tensor. Finally, the WKB method is used to calculate penetrabilities and spontaneous fission half-lives. Calculations are performed for the decay of 282,292120 nuclei.

  12. Systems study of tokamak fusion--fission reactors

    Energy Technology Data Exchange (ETDEWEB)

    Tenney, F.H.; Bathke, C.G.; Price, W.G. Jr.; Bohlke, W.H.; Mills, R.G.; Johnson, E.F.; Todd, A.M.M.; Buchanan, C.H.; Gralnick, S.L.

    1978-11-01

    This publication reports the results of a two to three year effort at a systematic analysis of a wide variety of tokamak-driven fissioning blanket reactors, i.e., fusion--fission hybrids. It addresses the quantitative problems of determining the economically most desirable mix of the two products: electric power and fissionable fuel and shows how the price of electric power can be minimized when subject to a variety of constraints. An attempt has been made to avoid restricting assumptions, and the result is an optimizing algorithm that operates in a six-dimensional parameter space. Comparisons are made on sets of as many as 100,000 distinct machine models, and the principal results of the study have been derived from the examination of several hundred thousand possible reactor configurations.

  13. Target development for the Munich fission fragment accelerator

    CERN Document Server

    Maier, H J; Gross, M L; Grossmann, R; Kester, O; Thirolf, P

    2002-01-01

    The target for the Munich Fission Fragment Accelerator (MAFF) consists of typically 1 g of the fission material sup 2 sup 3 sup 5 U in the form of UC sub 2 , dispersed homogeneously in a cylindrical graphite matrix, which is encapsulated in a protective Re container. This special type of target is currently under development. The problems related to its manufacture are discussed. To enable diffusion and extraction of the fission products, the target has to be maintained at a temperature of up to 2700 K during operation. Extensive tests are required to study the long-term behaviour of the involved materials at these conditions. For this purpose a resistively heated high vacuum furnace has been set up, which allows high-temperature heat treatment of target samples for a period of up to 1000 h.

  14. Development of Fission Chamber Assembly

    Institute of Scientific and Technical Information of China (English)

    YANGJinwei; ZHANGWei; SONGXianying; LIXu

    2003-01-01

    The fission chambers which are gas counters with fissile material inside chamber,provide essential information for plasma opcharacteristics. In conjunction with the neutron flux monitor system these provide time-resolved measurements of the global neutron source strength and fusion power from thermal nuclear fusion reactor as ITER for all plasma conditions for which neutrons are produced.

  15. Asthma Basics

    Science.gov (United States)

    ... Old Feeding Your 1- to 2-Year-Old Asthma Basics KidsHealth > For Parents > Asthma Basics A A ... Asthma Categories en español Asma: aspectos fundamentales About Asthma Asthma is a common lung condition in kids ...

  16. Starch Products. Learning Activity Pack and Instructor's Guide 5.9. Commercial Foods and Culinary Arts Competency-Based Series. Section 5: Basic Food Preparation.

    Science.gov (United States)

    Florida State Univ., Tallahassee. Center for Studies in Vocational Education.

    This document consists of a learning activity packet (LAP) for the student and an instructor's guide for the teacher. The LAP is intended to acquaint occupational home economics students with some basic information about starches and with three starch products found throughout the world: cereals and rice, potatoes, and pasta. Illustrated…

  17. Cumulative fission yields of short-lived isotopes under natural-abundance-boron-carbide-moderated neutron spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Finn, Erin C.; Metz, Lori A.; Greenwood, Lawrence R.; Pierson, Bruce; Wittman, Richard S.; Friese, Judah I.; Kephart, Rosara F.

    2015-04-09

    The availability of gamma spectroscopy data on samples containing mixed fission products at short times after irradiation is limited. Due to this limitation, data interpretation methods for gamma spectra of mixed fission product samples, where the individual fission products have not been chemically isolated from interferences, are not well-developed. The limitation is particularly pronounced for fast pooled neutron spectra because of the lack of available fast reactors in the United States. Samples containing the actinide isotopes 233, 235, 238U, 237Np, and 239Pu individually were subjected to a 2$ pulse in the Washington State University 1 MW TRIGA reactor. To achieve a fission-energy neutron spectrum, the spectrum was tailored using a natural abundance boron carbide capsule to absorb neutrons in the thermal and epithermal region of the spectrum. Our tailored neutron spectrum is unique to the WSU reactor facility, consisting of a soft fission spectrum that contains some measurable flux in the resonance region. This results in a neutron spectrum at greater than 0.1 keV with an average energy of 70 keV, similar to fast reactor spectra and approaching that of 235U fission. Unique fission product gamma spectra were collected from 4 minutes to 1 week after fission using single-crystal high purity germanium detectors. Cumulative fission product yields measured in the current work generally agree with published fast pooled fission product yield values from ENDF/B-VII, though a bias was noted for 239Pu. The present work contributes to the compilation of energy-resolved fission product yield nuclear data for nuclear forensic purposes.

  18. Status update on the NIFFTE high precision fission cross section measurement program

    Energy Technology Data Exchange (ETDEWEB)

    Laptev, Alexander B [Los Alamos National Laboratory; Tovesson, Fredrik [Los Alamos National Laboratory; Burgett, Eric [GEORGIA INSTITUTE OF TECH; Greife, Uwe [COLORADO SCHOOL OF THE MINES; Grimes, Steven [OHIO UNIV; Heffner, Michael D [LLNL; Hertel, Nolan E [GEORGIA INSTITUTE OF TECH; Hill, Tony [IDAHO NATIONAL LABORATORY; Isenhower, Donald [ABILENE CHRISTIN UNIV; Klay, Jennifer L [CALIFORNIA POLYTECHNIC STATE UNIV; Kornilov, Nickolay [OHIO UNIV; Kudo, Ryuho [CALIFORNIA POLYTECHNIC STATE UNIV; Loveland, Walter [OREGON STATE UNIV; Massey, Thomas [OHIO UNIV; Mc Grath, Chris [IDAHO NATIONAL LABORATORY; Pickle, Nathan [ABILENE CHRISTIAN UNIV; Qu, Hai [ABILENE CHRISTIAN UNIV; Sharma, Sarvagya [ABILENE CHRISTIAN UNIV; Snyder, Lucas [COLORADO SCHOOL OF THE MINES; Thornton, Tyler [ABILENE CHRISTIAN UNIV; Towell, Rusty S [ABILENE CHRISTIAN UNIV; Watson, Shon [ABILENE CHRISTIAN UNIV

    2010-01-01

    The Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) program has been underway for nearly two years. The program's mission is to measure fission cross sections of the primary fissionable and fissile materials ({sup 235}U, {sup 239}Pu, {sup 238}U) as well as the minor actinides across energies from approximately 50 keV up to 20 MeV with an absolute uncertainty of less than one percent while investigating energy ranges from below an eV to 600 MeV. This basic nuclear physics data is being reinvestigated to support the next generation power plants and a fast burner reactor program. Uncertainties in the fast, resolved and unresolved resonance regions in plutonium and other transuranics are extremely large, dominating safety margins in the next generation nuclear power plants and power plants of today. This basic nuclear data can be used to support all aspects of the nuciear renaissance. The measurement campaign is utilizing a Time Projection Chamber or TPC as the tool to measure these cross sections to these unprecedented levels. Unlike traditional fission cross section measurements using time-of-flight and a multiple fission foil configurations in which fission cross sections in relation to that of {sup 235}U are performed, the TPC project uses time-of-flight and hydrogen as the benchmark cross section. Using the switch to hydrogen, a simple, smooth cross section that can be used which removes the uncertainties associated with the resolved and unresolved resonances in {sup 235}U.

  19. Phebus PF (fission products): major international research programme in nuclear safety; Phebus PF: programme international majeur de recherche en surete nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-06-01

    The objective consists in reproducing experimentally at small scale the core meltdown in a PWR type reactor, in order to study the mechanisms of core meltdown, as well as the quantity, the nature and the behaviour of radioactive products released in such a situation. The programme Phebus PF aims to improve the knowledge of these phenomena. This knowledge must allow to better appreciate the procedures and means to prevent and limit the consequences of such accidents. (N.C.)

  20. Effects of Fission Yield Data in the Calculation of Antineutrino Spectra for 235U (n ,fission) at Thermal and Fast Neutron Energies

    Science.gov (United States)

    Sonzogni, A. A.; McCutchan, E. A.; Johnson, T. D.; Dimitriou, P.

    2016-04-01

    Fission yields form an integral part of the prediction of antineutrino spectra generated by nuclear reactors, but little attention has been paid to the quality and reliability of the data used in current calculations. Following a critical review of the thermal and fast ENDF/B-VII.1 235U 235 fission yields, deficiencies are identified and improved yields are obtained, based on corrections of erroneous yields, consistency between decay and fission yield data, and updated isomeric ratios. These corrected yields are used to calculate antineutrino spectra using the summation method. An anomalous value for the thermal fission yield of 86Ge generates an excess of antineutrinos at 5-7 MeV, a feature which is no longer present when the corrected yields are used. Thermal spectra calculated with two distinct fission yield libraries (corrected ENDF/B and JEFF) differ by up to 6% in the 0-7 MeV energy window, allowing for a basic estimate of the uncertainty involved in the fission yield component of summation calculations. Finally, the fast neutron antineutrino spectrum is calculated, which at the moment can only be obtained with the summation method and may be relevant for short baseline reactor experiments using highly enriched uranium fuel.

  1. Effects of Fission Yield Data in the Calculation of Antineutrino Spectra for ^{235}U(n,fission) at Thermal and Fast Neutron Energies.

    Science.gov (United States)

    Sonzogni, A A; McCutchan, E A; Johnson, T D; Dimitriou, P

    2016-04-01

    Fission yields form an integral part of the prediction of antineutrino spectra generated by nuclear reactors, but little attention has been paid to the quality and reliability of the data used in current calculations. Following a critical review of the thermal and fast ENDF/B-VII.1 ^{235}U fission yields, deficiencies are identified and improved yields are obtained, based on corrections of erroneous yields, consistency between decay and fission yield data, and updated isomeric ratios. These corrected yields are used to calculate antineutrino spectra using the summation method. An anomalous value for the thermal fission yield of ^{86}Ge generates an excess of antineutrinos at 5-7 MeV, a feature which is no longer present when the corrected yields are used. Thermal spectra calculated with two distinct fission yield libraries (corrected ENDF/B and JEFF) differ by up to 6% in the 0-7 MeV energy window, allowing for a basic estimate of the uncertainty involved in the fission yield component of summation calculations. Finally, the fast neutron antineutrino spectrum is calculated, which at the moment can only be obtained with the summation method and may be relevant for short baseline reactor experiments using highly enriched uranium fuel.

  2. Transfer-induced fission in inverse kinematics: Impact on experimental and evaluated nuclear data bases

    Science.gov (United States)

    Farget, F.; Caamaño, M.; Ramos, D.; Rodrıguez-Tajes, C.; Schmidt, K.-H.; Audouin, L.; Benlliure, J.; Casarejos, E.; Clément, E.; Cortina, D.; Delaune, O.; Derkx, X.; Dijon, A.; Doré, D.; Fernández-Domınguez, B.; Gaudefroy, L.; Golabek, C.; Heinz, A.; Jurado, B.; Lemasson, A.; Paradela, C.; Roger, T.; Salsac, M. D.; Schmitt, C.

    2015-12-01

    Inverse kinematics is a new tool to study nuclear fission. Its main advantage is the possibility to measure with an unmatched resolution the atomic number of fission fragments, leading to new observables in the properties of fission-fragment distributions. In addition to the resolution improvement, the study of fission based on nuclear collisions in inverse kinematics beneficiates from a larger view with respect to the neutron-induced fission, as in a single experiment the number of fissioning systems and the excitation energy range are widden. With the use of spectrometers, mass and kinetic-energy distributions may now be investigated as a function of the proton and neutron number sharing. The production of fissioning nuclei in transfer reactions allows studying the isotopic yields of fission fragments as a function of the excitation energy. The higher excitation energy resulting in the fusion reaction leading to the compound nucleus 250Cf at an excitation energy of 45MeV is also presented. With the use of inverse kinematics, the charge polarisation of fragments at scission is now revealed with high precision, and it is shown that it cannot be neglected, even at higher excitation energies. In addition, the kinematical properties of the fragments inform on the deformation configuration at scission.

  3. Transfer-induced fission in inverse kinematics: Impact on experimental and evaluated nuclear data bases

    Energy Technology Data Exchange (ETDEWEB)

    Farget, F.; Schmidt, K.H.; Clement, E.; Delaune, O.; Derkx, X.; Dijon, A.; Golabek, C.; Lemasson, A.; Roger, T.; Schmitt, C. [CEA/DSM-CNRS/IN2P3, GANIL, Caen (France); Caamano, M.; Ramos, D.; Benlliure, J.; Cortina, D.; Fernandez-Dominguez, B.; Paradela, C. [Universidade de Santiago de Compostela, Santiago de Compostela (Spain); Rodriguez-Tajes, C. [CEA/DSM-CNRS/IN2P3, GANIL, Caen (France); Universidade de Santiago de Compostela, Santiago de Compostela (Spain); Audouin, L. [Universite Paris-Sud 11, CNRS/IN2P3, Institut de Physique Nucleaire, Orsay (France); Casarejos, E. [Universidade de Vigo, Vigo (Spain); Dore, D.; Salsac, M.D. [Centre de Saclay, CEA, Irfu, Gif-sur-Yvette (France); Gaudefroy, L. [CEA DAM Ile-de-France, BP 12, Bruyeres-le-Chatel (France); Heinz, A. [Chalmers Tekniska Hoegskola, Fundamental Fysik, Goeteborg (Sweden); Jurado, B. [Universite Bordeaux, CENBG, UMR 5797 CNRS/IN2P3, Gradignan (France)

    2015-12-15

    Inverse kinematics is a new tool to study nuclear fission. Its main advantage is the possibility to measure with an unmatched resolution the atomic number of fission fragments, leading to new observables in the properties of fission-fragment distributions. In addition to the resolution improvement, the study of fission based on nuclear collisions in inverse kinematics beneficiates from a larger view with respect to the neutron-induced fission, as in a single experiment the number of fissioning systems and the excitation energy range are widden. With the use of spectrometers, mass and kinetic-energy distributions may now be investigated as a function of the proton and neutron number sharing. The production of fissioning nuclei in transfer reactions allows studying the isotopic yields of fission fragments as a function of the excitation energy. The higher excitation energy resulting in the fusion reaction leading to the compound nucleus {sup 250}Cf at an excitation energy of 45MeV is also presented. With the use of inverse kinematics, the charge polarisation of fragments at scission is now revealed with high precision, and it is shown that it cannot be neglected, even at higher excitation energies. In addition, the kinematical properties of the fragments inform on the deformation configuration at scission. (orig.)

  4. Two neutron correlations in photo-fission

    Science.gov (United States)

    Dale, D. S.; Kosinov, O.; Forest, T.; Burggraf, J.; Stave, S.; Warren, G.; Starovoitova, V.

    2016-09-01

    A large body of experimental work has established the strong kinematical correlation between fission fragments and fission neutrons. Here, we report on the progress of investigations of the potential for strong two neutron correlations arising from the nearly back-to-back nature of the two fission fragments that emit these neutrons in the photo-fission process. In initial measurements, a pulsed electron linear accelerator was used to generate bremsstrahlung photons that impinged upon an actinide target, and the energy and opening angle distributions of coincident neutrons were measured using a large acceptance neutron detector array. A planned comprehensive set of measurements of two neutron correlations in the photo-fission of actinides is expected to shed light on several fundamental aspects of the fission process including the multiplicity distributions associated with the light and heavy fission fragments, the nuclear temperatures of the fission fragments, and the mass distribution of the fission fragments as a function of energy released. In addition to these measurements providing important nuclear data, the unique kinematics of fission and the resulting two neutron correlations have the potential to be the basis for a new tool to detect fissionable materials. A key technical challenge of this program arises from the need to perform coincidence measurements with a low duty factor, pulsed electron accelerator. This has motivated the construction of a large acceptance neutron detector array, and the development of data analysis techniques to directly measure uncorrelated two neutron backgrounds.