WorldWideScience

Sample records for advanced fission energy

  1. 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

  2. Energy released in fission

    International Nuclear Information System (INIS)

    The effective energy released in and following the fission of U-235, Pu-239 and Pu-241 by thermal neutrons, and of U-238 by fission spectrum neutrons, is discussed. The recommended values are: U-235 ... 192.9 ± 0.5 MeV/fission; U-238 ... 193.9 ± 0.8 MeV/fission; Pu-239 ... 198.5 ± 0.8 MeV/fission; Pu-241 ... 200.3 ± 0.8 MeV/fission. These values include all contributions except from antineutrinos and very long-lived fission products. The detailed contributions are discussed, and inconsistencies in the experimental data are pointed out. In Appendix A, the contribution to the total useful energy release in a reactor from reactions other than fission are discussed briefly, and in Appendix B there is a discussion of the variations in effective energy from fission with incident neutron energy. (author)

  3. Key nuclear data measurements for advanced fission energy and white neutron source at CSNS

    International Nuclear Information System (INIS)

    The key nuclear data for advanced fission energy are important in designing advanced nuclear reactors and facilities for nuclear-waste transmutation. Because the present nuclear data library is limited by experimental condition and energy range, the precision of some nuclear data is low, even some nuclear data are blank. In this paper, the status of the nuclear data and white neutron sources were presented. The back-streaming neutron beam at China Spallation Neutron Source (CSNS) has very wide energy spectrum (0.01 eV-200 MeV) and excellent time structure. From the simulation results, it's obtained that the uncollimated neutron fluence rate is around 9.3 × 106 cm-2 · s-1 within the given energy range at 80 m away from the target, which accounts for about 53% of the total neutrons. The time resolution of 0.3%-0.9%, which is important for the Time-of-Flight method, can be obtained for both the parasite operation mode with two proton bunches and the dedicated operation mode with a single proton bunch. CSNS white neutron source will be a good facility for nuclear data measurement. (authors)

  4. Intermediate energy nuclear fission

    International Nuclear Information System (INIS)

    Nuclear fission has been investigated with the double-kinetic-energy method using silicon surface barrier detectors. Fragment energy correlation measurements have been made for U, Th and Bi with bremsstrahlung of 600 MeV maximum energy. Distributions of kinetic energy as a function of fragment mass are presented. The results are compared with earlier photofission data and in the case of bismuth, with calculations based on the liquid drop model. The binary fission process in U, Yb, Tb, Ce, La, Sb, Ag and Y induced by 600 MeV protons has been investigated yielding fission cross sections, fragment kinetic energies, angular correlations and mass distributions. Fission-spallation competition calculations are used to deduce values of macroscopic fission barrier heights and nuclear level density parameter values at deformations corresponding to the saddle point shapes. We find macroscopic fission barriers lower than those predicted by macroscopic theories. No indication is found of the Businaro Gallone limit expected to occur somewhere in the mass range A = 100 to A = 140. For Ce and La asymmetric mass distributions similar to those in the actinide region are found. A method is described for the analysis of angular correlations between complementary fission products. The description is mainly concerned with fission induced by medium-energy protons but is applicable also to other projectiles and energies. It is shown that the momentum and excitation energy distributions of cascade residuals leading to fission can be extracted. (Author)

  5. Advanced Fission Reactor Program objectives

    International Nuclear Information System (INIS)

    The objective of an advanced fission reactor program should be to develop an economically attractive, safe, proliferation-resistant fission reactor. To achieve this objective, an aggressive and broad-based research and development program is needed. Preliminary work at Brookhaven National Laboratory shows that a reasonable goal for a research program would be a reactor combining as many as possible of the following features: (1) initial loading of uranium enriched to less than 15% uranium 235, (2) no handling of fuel for the full 30-year nominal core life, (3) inherent safety ensured by core physics, and (4) utilization of natural uranium at least 5 times as efficiently as light water reactors

  6. Low-energy ternary fission

    International Nuclear Information System (INIS)

    With the detector system DIOGENES thermal neutron induced and spontaneous α particle associated fission and spontaneous nuclear tripartition into three fragments of similar masses has been investigated. DIOGENES is a concentric arrangement of toroidal angular position sensitive ionization chambers and proportional counters to measure the kinetic energies and relative angular distributions of the three reaction products of ternary fission. For α-particle accompanied fission some of the many possible α particle fission-fragment parameter correlations will be discussed. For nearly symmetric low-energy nuclear tripartition new upper limits are presented. Former experimental results which pretended evidence for so called true ternary fission could be explained by charged-particle associated fission with a light particle in the mass range of 13 < A < 23

  7. Energy dependence of fission observables

    Science.gov (United States)

    Paşca, Horia

    2016-01-01

    The mass, charge and isotopic distributions of fission fragments are studied within an improved scission-point statistical model in the reaction 235U+n at different energies of the incident neutron. The available experimental data are well reproduced and the energy-dependencies of the observable characteristics of fission are predicted for future experiments. The calculated mass distribution of 238U+n is also compared with experimental data.

  8. 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.

  9. Fusion and fission of atomic clusters: recent advances

    DEFF Research Database (Denmark)

    Obolensky, Oleg I.; Solov'yov, Ilia; Solov'yov, Andrey V.;

    2005-01-01

    We review recent advances made by our group in finding optimized geometries of atomic clusters as well as in description of fission of charged small metal clusters. We base our approach to these problems on analysis of multidimensional potential energy surface. For the fusion process we have...... developed an effective scheme of adding new atoms to stable cluster geometries of larger clusters in an efficient way. We apply this algorithm to finding geometries of metal and noble gas clusters. For the fission process the analysis of the potential energy landscape calculated on the ab initio level...... of theory allowed us to obtain very detailed information on energetics and pathways of the different fission channels for the Na^2+_10 clusters....

  10. Energy partition in low energy fission

    OpenAIRE

    Mirea, M.

    2011-01-01

    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 another separates the pairing active spaces associated to the two fragments in the vicinity of the scission configuration. The fission path is obtained in the frame of the macroscopic-microscopic model. The single particle level schemes are obtained within the two ...

  11. Energy production using fission fragment rockets

    Science.gov (United States)

    Chapline, G.; Matsuda, Y.

    1991-08-01

    Fission fragment rockets are nuclear reactors with a core consisting of thin fibers in a vacuum, and which use magnetic fields to extract the fission fragments from the reactor core. As an alternative to ordinary nuclear reactors, fission fragment rockets would have the following advantages: approximately twice the efficiency if the fission fragment energy can be directly converted into electricity; reduction of the buildup of a fission fragment inventory in the reactor could avoid a Chernobyl type disaster; and collection of the fission fragments outside the reactor could simplify the waste disposal problem.

  12. Energy production using fission fragment rockets

    International Nuclear Information System (INIS)

    Fission fragment rockets are nuclear reactors with a core consisting of thin fibers in a vacuum, and which use magnetic fields to extract the fission fragments from the reactor core. As an alternative to ordinary nuclear reactors, fission fragment rockets would have the following advantages: Approximately twice as efficient if one can directly convert the fission fragment energy into electricity; by reducing the buildup of a fission fragment inventory in the reactor one could avoid a Chernobyl type disaster; and collecting the fission fragments outside the reactor could simplify the waste disposal problem. 6 refs., 4 figs., 2 tabs

  13. Fusion-fission energy systems evaluation

    International Nuclear Information System (INIS)

    This report serves as the basis for comparing the fusion-fission (hybrid) energy system concept with other advanced technology fissile fuel breeding concepts evaluated in the Nonproliferation Alternative Systems Assessment Program (NASAP). As such, much of the information and data provided herein is in a form that meets the NASAP data requirements. Since the hybrid concept has not been studied as extensively as many of the other fission concepts being examined in NASAP, the provided data and information are sparse relative to these more developed concepts. Nevertheless, this report is intended to provide a perspective on hybrids and to summarize the findings of the rather limited analyses made to date on this concept

  14. Fusion-fission energy systems evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Teofilo, V.L.; Aase, D.T.; Bickford, W.E.

    1980-01-01

    This report serves as the basis for comparing the fusion-fission (hybrid) energy system concept with other advanced technology fissile fuel breeding concepts evaluated in the Nonproliferation Alternative Systems Assessment Program (NASAP). As such, much of the information and data provided herein is in a form that meets the NASAP data requirements. Since the hybrid concept has not been studied as extensively as many of the other fission concepts being examined in NASAP, the provided data and information are sparse relative to these more developed concepts. Nevertheless, this report is intended to provide a perspective on hybrids and to summarize the findings of the rather limited analyses made to date on this concept.

  15. Improved Calculation of Thermal Fission Energy

    OpenAIRE

    Ma, X. B.; Zhong, W. L.; Wang, L. Z.; Y. X. Chen; Cao, J

    2012-01-01

    Thermal fission energy is one of the basic parameters needed in the calculation of antineutrino flux for reactor neutrino experiments. It is useful to improve the precision of the thermal fission energy calculation for current and future reactor neutrino experiments, which are aimed at more precise determination of neutrino oscillation parameters. In this article, we give new values for thermal fission energies of some common thermal reactor fuel isotopes, with improvements on three aspects. ...

  16. Fission dynamics at low excitation energy

    CERN Document Server

    Aritomo, Y

    2013-01-01

    The origin of mass asymmetry in the fission of uranium at a low excitation energy is clarified by a trajectory analysis of the Langevin equation. The positions of the peaks in the mass distribution of fission fragments are mainly determined by fission saddle points originating from the shell correction energy. The widths of the peaks, on the other hand, result from a shape fluctuation around the scission point caused by the random force in the Langevin equation. We found that a random vibration in the oblate direction of fissioning fragments is essential for the fission process. According to this picture, fission does not occur with continuous stretching in the prolate direction, similarly to that observed in starch syrup. This is expected to lead to a new viewpoint of fission dynamics and the splitting mechanism.

  17. Fission dynamics at low excitation energy

    OpenAIRE

    Aritomo, Y.; Chiba, S.

    2013-01-01

    The origin of mass asymmetry in the fission of uranium at a low excitation energy is clarified by a trajectory analysis of the Langevin equation. The positions of the peaks in the mass distribution of fission fragments are mainly determined by fission saddle points originating from the shell correction energy. The widths of the peaks, on the other hand, result from a shape fluctuation around the scission point caused by the random force in the Langevin equation. We found that a random vibrati...

  18. Structural materials for fission & fusion energy

    Directory of Open Access Journals (Sweden)

    Steven J. Zinkle

    2009-11-01

    Full Text Available Structural materials represent the key for containment of nuclear fuel and fission products as well as reliable and thermodynamically efficient production of electrical energy from nuclear reactors. Similarly, high-performance structural materials will be critical for the future success of proposed fusion energy reactors, which will subject the structures to unprecedented fluxes of high-energy neutrons along with intense thermomechanical stresses. Advanced materials can enable improved reactor performance via increased safety margins and design flexibility, in particular by providing increased strength, thermal creep resistance and superior corrosion and neutron radiation damage resistance. In many cases, a key strategy for designing high-performance radiation-resistant materials is based on the introduction of a high, uniform density of nanoscale particles that simultaneously provide good high temperature strength and neutron radiation damage resistance.

  19. 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 ...

  20. Calculated medium energy fission cross sections

    International Nuclear Information System (INIS)

    An analysis has been made of medium-energy nucleon induced fission of 238U and 237Np using detailed models of fission, based upon the Bohr-Wheeler formalism. Two principal motivations were associated with these calculations. The first was determination of barrier parameters for proton-rich uranium and neptunium isotopes normally not accessible in lower energy reactions. The second was examination of the consistency between (p,f) experimental data versus new (n,f) data that has recently become available. Additionally, preliminary investigations were also made concerning the effect of fission dynamics on calculated fission cross sections at higher energies where neutron emission times may be significantly less than those associated with fission

  1. Fission dynamics at low excitation energy. 2

    CERN Document Server

    Aritomo, Y; Ivanyuk, F A

    2014-01-01

    The mass asymmetry in the fission of U-236 at low excitation energy is clarified by the analysis of the trajectories obtained by solving the Langevin equations for the shape degrees of freedom. It is demonstrated that the position of the peaks in the mass distribution of fission fragments is determined mainly by the saddle point configuration originating from the shell correction energy. The width of the peaks, on the other hand, results from the shape fluctuations close to the scission point caused by the random force in the Langevin equation. We have found out that the fluctuations between elongated and compact shapes are essential for the fission process. According to our results the fission does not occur with continuous stretching in the prolate direction, similarly to that observed in starch syrup, but is accompanied by the fluctuations between elongated and compact shapes. This picture presents a new viewpoint of fission dynamics and the splitting mechanism.

  2. Advanced Modeling of Prompt Fission Neutrons and Gamma Rays

    Directory of Open Access Journals (Sweden)

    Kawano T.

    2010-03-01

    Full Text Available Prompt fission neutrons and gamma rays are computed using a Monte Carlo treatment of the statistical evaporation of the excited primary fission fragments. The assumption of two fragments in thermal equilibrium at the time of neutron emission is addressed by studying the neutron multiplicity as a function of fragment mass. Results for the neutron-induced fission of 235U are discussed, for incident neutron energies from 0.5 to 5.5 MeV. Recent experimental data on the fission fragment yields as a function of mass and total kinetic energy are used as input data.

  3. Advanced Modeling of Prompt Fission Neutrons and Gamma Rays

    OpenAIRE

    Kawano T; Talou P.

    2010-01-01

    Prompt fission neutrons and gamma rays are computed using a Monte Carlo treatment of the statistical evaporation of the excited primary fission fragments. The assumption of two fragments in thermal equilibrium at the time of neutron emission is addressed by studying the neutron multiplicity as a function of fragment mass. Results for the neutron-induced fission of 235U are discussed, for incident neutron energies from 0.5 to 5.5 MeV. Recent experimental data on the fission fragment yield...

  4. Fission induced by nucleons at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Lo Meo, S., E-mail: sergio.lomeo@enea.it [ENEA, Centro Ricerche Ezio Clementel, 40129 Bologna (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Bologna, 40127 Bologna (Italy); Mancusi, D., E-mail: davide.mancusi@cea.fr [CEA, Centre de Saclay, Irfu/SPhN, F91191 Gif-sur-Yvette Cedex (France); Massimi, C., E-mail: cristian.massimi@bo.infn.it [Dipartimento di Fisica ed Astronomia dell' Università di Bologna (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Bologna, 40127 Bologna (Italy); Vannini, G., E-mail: gianni.vannini@bo.infn.it [Dipartimento di Fisica ed Astronomia dell' Università di Bologna (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Bologna, 40127 Bologna (Italy); Ventura, A., E-mail: alberto.ventura@bo.infn.it [Istituto Nazionale di Fisica Nucleare, Sezione di Bologna, 40127 Bologna (Italy)

    2015-01-15

    Monte Carlo calculations of fission of actinides and pre-actinides induced by protons and neutrons in the energy range from 100 MeV to 1 GeV are carried out by means of a recent version of the Liège Intranuclear Cascade Model, INCL++, coupled with two different evaporation-fission codes, GEMINI++ and ABLA07. In order to reproduce experimental fission cross sections, model parameters are usually adjusted on available (p,f) cross sections and used to predict (n,f) cross sections for the same isotopes.

  5. Fission induced by nucleons at intermediate energies

    CERN Document Server

    Meo, Sergio Lo; Massimi, Cristian; Vannini, Gianni; Ventura, Alberto

    2014-01-01

    Monte Carlo calculations of fission of actinides and pre-actinides induced by protons and neutrons in the energy range from 100 MeV to 1 GeV are carried out by means of a recent version of the Li\\`ege Intranuclear Cascade Model, INCL++, coupled with two different evaporation-fission codes, GEMINI++ and ABLA07. In order to reproduce experimental fission cross sections, model parameters are usually adjusted on available (p,f) cross sections and used to predict (n,f) cross sections for the same isotopes.

  6. Low energy fission: dynamics and scission configurations

    International Nuclear Information System (INIS)

    In the first part of this paper we recall a recent study concerning low energy fission dynamics. Propagation is made by use of the Time Dependent Generator Coordinate Method, where the basis states are taken from self-consistent Hartree-Fock-Bogoliubov calculations with the Gogny force. Theoretical fragment mass distributions are presented and compared with the evaluation made by Wahl. In the second part of this paper, new results concerning scission configurations are shown. Deviations of the fission fragment proton numbers from the Unchanged Charge Distribution prescription and fission fragment deformations are discussed. (authors)

  7. 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...

  8. Nucleon-induced fission at intermediate energies

    International Nuclear Information System (INIS)

    The absence of a satisfactory theoretical description to predict isotope yields as well as the need for experimental fragment mass and charge distributions at intermediate-energies form the motivation of this work. Like the objects under study, the research presented in this thesis consists two main parts. Part 1 concerns an activation experiment that has been performed at the 'Kernfysisch Versneller Instituut' (Nuclear Physics Accelerator Institute) in Groningen, Netherlands, using the AGOR cyclotron. Fission product yields have been measured resulting from 190 MeV proton-induced fission of natW, 197Au, natPb, 208Pb and 232Th. In Chapter 2 the experimental set up is discussed, followed in Chapter 3 by a description of the data analysis. The results on the reconstructed mass yields and the total fission cross sections are presented in Chapter 4. Part 2 is of a theoretical nature. The objective is to compute fission product mass yields from intermediate-energy nucleon-induced reactions. In the approach presented here, two stages can be distinguished. In the first stage the fission cross section is determined for the various fissioning isotopes as a function of their excitation energy in competition with other processes like pre-equilibrium decay and particle evaporation. ALICE-91 is a nuclear reaction code that takes care of this first stage. The second stage consists of constructing the total fission-fragment mass and charge distributions from the different contributions of all the equilibrated fissioning systems. Hence, a model is needed that gives a prediction for the fission-product mass yields in a large range of mass, charge, and excitation energy of the fissioning nucleus. For this purpose, the multi-modal random neck-rupture model by Brosa is extended with temperature-dependent shell and pairing corrections and a temperature-dependent LDM. The combination of ALICE-91 and the modified Brosa approach is used for the analysis of the experiments given in the

  9. Energy Correlation of Prompt Fission Neutrons

    Science.gov (United States)

    Elter, Zs.; Pázsit, I.

    2016-03-01

    In all cases where neutron fluctuations in a branching process (such as in multiplicity measurements) are treated in an energy dependent description, the energy correlations of the branching itself (energy correlations of the fission neutrons) need to be known. To date, these are not known from experiments. Such correlations can be theoretically and numerically derived by modelling the details of the fission process. It was suggested earlier that the fact that the prompt neutrons are emitted from the moving fission targets, will influence their energy and angular distributions in the lab system, which possibly induces correlations. In this paper the influence of the neutron emission process from the moving targets on the energy correlations is investigated analytically and via numerical simulations. It is shown that the correlations are generated by the random energy and direction distributions of the fission fragments. Analytical formulas are derived for the two-point energy distributions, and quantitative results are obtained by Monte-Carlo simulations. The results lend insight into the character of the two-point distributions, and give quantitative estimates of the energy correlations, which are generally small.

  10. Energy Correlation of Prompt Fission Neutrons

    Directory of Open Access Journals (Sweden)

    Elter Zs.

    2016-01-01

    Full Text Available In all cases where neutron fluctuations in a branching process (such as in multiplicity measurements are treated in an energy dependent description, the energy correlations of the branching itself (energy correlations of the fission neutrons need to be known. To date, these are not known from experiments. Such correlations can be theoretically and numerically derived by modelling the details of the fission process. It was suggested earlier that the fact that the prompt neutrons are emitted from the moving fission targets, will influence their energy and angular distributions in the lab system, which possibly induces correlations. In this paper the influence of the neutron emission process from the moving targets on the energy correlations is investigated analytically and via numerical simulations. It is shown that the correlations are generated by the random energy and direction distributions of the fission fragments. Analytical formulas are derived for the two-point energy distributions, and quantitative results are obtained by Monte-Carlo simulations. The results lend insight into the character of the two-point distributions, and give quantitative estimates of the energy correlations, which are generally small.

  11. Fission energy program of the US Department of Energy, FY 1981

    International Nuclear Information System (INIS)

    Information is presented concerning the National Energy Plan and fission energy policy; fission energy program management; converter reactor systems; breeder reactor systems; and special nuclear evaluations and systems

  12. Fission energy program of the US Department of Energy, FY 1981

    Energy Technology Data Exchange (ETDEWEB)

    Ferguson, Robert L.

    1980-03-01

    Information is presented concerning the National Energy Plan and fission energy policy; fission energy program management; converter reactor systems; breeder reactor systems; and special nuclear evaluations and systems.

  13. Derivation of Energy Generated by Nuclear Fission-Fusion Reaction

    OpenAIRE

    Kayano, Hideo; Teshigawara, Makoto; Konashi, Kenji; Yamamoto, Takuya

    1994-01-01

    In the solids which contain fissionable elements and deuterium, it is expected that the energy generated by nuclear fission contributes to the promotion of the D-D nuclear fusion in the solids. When nuclear fission occurs by neutrons in the solid, the fissionable elements divide into two fission product nuclei having the energy of 100MeV, respectively. It is expected that the hige energy fission products promote rapidly nuclear fision reaction by knocking out the D atoms in the solids and by ...

  14. Measurement of fission fragments energy loss

    CERN Document Server

    Benetti, P; Calligarich, E; Cesana, A; Dolfini, R; Ioppolo, T; Raselli, G L; Terrani, M

    2002-01-01

    The mean energy of sup 2 sup 5 sup 2 Cf fission fragments emerging from an absorber and the determination of the capture rate in the absorber itself have been measured using two independent and complementary nuclear techniques. The results can be applied to the measurement of the energy self-absorption in a non-zero thickness source and can be used to validate simulation programs.

  15. Excitation-energy dependence of the nuclear fission characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Baba, H.; Saito, T.; Takahashi, N. [Osaka City Univ. (Japan). Faculty of Science] [and others

    1996-03-01

    It is known that the width parameter of the fragment mass yield distribution follows a beautiful systematics with respect to the excitation energy. According to this systematics, the fission characteristics following the systematics should disappear when the excitation energy Ex goes down to 14 MeV. The present purpose is to elucidate if, where, how and why a transition takes place in the fission characteristics of the asymmetric fission of light actinide elements. Two types of experiments are performed, one is the double-energy measurement of the kinetic energies of complementary fragments in the thermal-neutron fission of {sup 235,233}U and proton-induced fission of {sup 238}U at 13.3- and 15.7-MeV excitations, and the other is the radiochemical study of proton-induced fission and photofission of {sup 238}U at various excitation energies. In conclusion, it has demonstrated that there are two distinctive fission mechanisms in the low-energy fission of light actinide elements and the transition between them takes place around 14-MeV excitation. The characteristics of proton fission and photofission in the energy range lower than the above transition point are the essentially the same as those of thermal-neutron fission and also spontaneous fission. The results of GDR fission indicates the fission in the high-energy side starts from the nuclear collective states, whereas the lower-energy fission is of non-collective nature. It is likely that thermal-neutron fission is rather of the barrier-penetrating type like spontaneous fission than the threshold fission. (S.Y.)

  16. Mass and Charge Distribution in Low-Energy Fission

    International Nuclear Information System (INIS)

    The mass and charge distributions for thermal-neutron fission of U235 are discussed in considerable detail and compared with the corresponding distributions in other low-energy fission processes. Points discussed in connection with the mass distributions for binary fission include the positions of the peaks, valley and fine structure in a mass yield curve with respect to filled nuclear shells and the changes in the positions that occur with changing fissioning nucleus and excitation energy. The mass distribution from ternary fission is discussed also. For both binary and ternary fission comments are made concerning the mass distributions of primary fragments (before neutron evaporation) and of fission products (after neutron evaporation). Charge distribution is discussed in terms of charge dispersion among fission products with the same mass number and the variation with mass number of Zp, the ''most probable charge'' (non-integral) for a given mass number. Although direct information about charge distribution is limited to fission products, estimates are presented of charge distribution for primary fission fragments. Knowledge and estimates of mass and charge distribution for a fission process allow estimation of primary yields of all fission products or fragments. Although many estimated primary yields are quite uncertain mainly because of lack of knowledge of charge distribution, especially for fission products formed in low yield; some estimates of primary yields are presented to illustrate the need for and possible practicality of further experimentation. Fission processes other than thermal-neutron fission of U235 that are discussed include thermal-neutron fission of U233 and Pu239, spontaneous fission of Pu240 and Cf252, 14-MeV neutron fission of U235 and U238, 11-MeV proton fission of Ra226 and 22-MeV deuteron fission of Bi209. (author)

  17. Effects of fissioning nuclei distributions on fragment mass distributions for high energy fission

    Directory of Open Access Journals (Sweden)

    Rossi P C R

    2012-02-01

    Full Text Available We study the effects of fissioning nuclei mass- and energy-distributions on the formation of fragments for fission induced by high energy probes. A Monte Carlo code called CRISP was used for obtaining mass distributions and spectra of the fissioning nuclei for reactions induced by 660 MeV protons on 241Am and on 239Np, by 500 MeV protons on 208Pb, and by Bremsstrahlung photons with end-point energies at 50 MeV and 3500 MeV on 238U. The results show that even at high excitation energies, asymmetric fission may still contribute significantly to the fission cross section of actinide nuclei, while it is the dominante mode in the case of lead. However, more precise data for high energy fission on actinide are necessary in order to allow definite conclusions.

  18. Energy Dependence of Plutonium Fission-Product Yields

    International Nuclear Information System (INIS)

    A method is developed for interpolating between and/or extrapolating from two pre-neutron-emission first-chance mass-asymmetric fission-product yield curves. Measured 240Pu spontaneous fission and thermal-neutron-induced fission of 239Pu fission-product yields (FPY) are extrapolated to give predictions for the energy dependence of the n + 239Pu FPY for incident neutron energies from 0 to 16 MeV. After the inclusion of corrections associated with mass-symmetric fission, prompt-neutron emission, and multi-chance fission, model calculated FPY are compared to data and the ENDF/B-VII.1 evaluation. The ability of the model to reproduce the energy dependence of the ENDF/B-VII.1 evaluation suggests that plutonium fission mass distributions are not locked in near the fission barrier region, but are instead determined by the temperature and nuclear potential-energy surface at larger deformation.

  19. Energy Dependence of Plutonium Fission-Product Yields

    Science.gov (United States)

    Lestone, J. P.

    2011-12-01

    A method is developed for interpolating between and/or extrapolating from two pre-neutron-emission first-chance mass-asymmetric fission-product yield curves. Measured 240Pu spontaneous fission and thermal-neutron-induced fission of 239Pu fission-product yields (FPY) are extrapolated to give predictions for the energy dependence of the n + 239Pu FPY for incident neutron energies from 0 to 16 MeV. After the inclusion of corrections associated with mass-symmetric fission, prompt-neutron emission, and multi-chance fission, model calculated FPY are compared to data and the ENDF/B-VII.1 evaluation. The ability of the model to reproduce the energy dependence of the ENDF/B-VII.1 evaluation suggests that plutonium fission mass distributions are not locked in near the fission barrier region, but are instead determined by the temperature and nuclear potential-energy surface at larger deformation.

  20. Advanced modeling of prompt fission neutrons and gamma rays

    International Nuclear Information System (INIS)

    Prompt fission neutrons and gamma rays are computed using a Monte Carlo treatment of the statistical evaporation of the excited primary fission fragments. The assumption of two fragments in thermal equilibrium at the time of neutron emission is addressed by studying the neutron multiplicity as a function of fragment mass. Results for the neutron-induced fission of 235U are discussed, for incident neutron energies from 0.5 to 5.5 MeV. Recent experimental data on the fission fragment yields as a function of mass and total kinetic energy are used as input data. Monte-Carlo calculations allow the exploration of physical observables beyond average quantities. A new parameter RT has been introduced: RT=Tl/Th where Tl and Th are the temperatures in the light and heavy fragments. The average neutron multiplicity computed as a function of the fragment mass agrees best with the experimental data (with En=5.5 MeV) when RT=1 which can be understood as follows: as the incident neutron energy increases, the role of shell effects diminishes and the ratio of collective energies stored in the light and heavy fragment tends toward 1

  1. The changing face of fission track dating: recent advances

    International Nuclear Information System (INIS)

    Fission Track Dating has undergone something of a renaissance in recent years. What began as a rather unreliable method of geochronology has now become a rigorous and dependable means of measuring not only geological time but also paleotemperatures. Developments such as the zeta calibration technique, rigorous satistical data analysis, investigation of confined track lengths and detailed studies of annealing behaviour have all contributed to advances in the technique

  2. Evolution of isotopic fission-fragment yields with excitation energy

    International Nuclear Information System (INIS)

    Two fission experiments have been performed at GANIL using 238U beams at different energies and light targets. Different fissioning systems were produced with excitation energies from 10 to 230 MeV and their decay by fission was investigated with GANIL spectrometers. Preliminary fission-fragment isotopic distributions have been obtained. The evolution with impinging energy of their properties, the neutron excess and the width of the neutron-number distributions, gives important insights into the dynamics of fusion-fission mechanism. (authors)

  3. Evolution of isotopic fission-fragment yields with excitation energy

    Directory of Open Access Journals (Sweden)

    Bazin D.

    2012-07-01

    Full Text Available Two fission experiments have been performed at GANIL using 238U beams at different energies and light targets. Different fissioning systems were produced with excitation energies from 10 to 230 MeV and their decay by fission was investigated with GANIL spectrometers. Preliminary fission-fragment isotopic distributions have been obtained. The evolution with impinging energy of their properties, the neutron excess and the width of the neutron-number distributions, gives important insights into the dynamics of fusion-fission mechanism.

  4. Fast Neutron Induced Fission neutron Spectra Below the Incident Energy

    Energy Technology Data Exchange (ETDEWEB)

    Woodring, Mitchell L.; Egan, James J.; Kegel, Gunter H.; DeSimone, David J.

    2008-06-15

    Fission neutron spectra from neutron induced fission in 235U and 239Pu for energies below that of the neutron inducing fission have been measured. The spectra were obtained for 1.5 MeV and 2.5 MeV incident neutrons. Previous accelerator-based fission neutron spectra measurements have been seriously complicated by time-correlated gamma rays and scattered neutrons from the fission sample. Three barium fluoride detectors were placed near the sample undergoing induced fission and used to identify fission gamma rays. A coincidence of fission gamma rays was used to gate a liquid scintillator neutron detector to distinguish fission events from other events. The fission neutron spectral shape and average energy measured in this experiment compare well to both previous measurements and prior theory and also suggest a dependence on incident neutron energy and mass of the fissioning nucleus. An overview of the experiment, a discussion of the results, and the importance of this work to homeland security are given.

  5. About total kinetic energy distribution between fragments of binary fission

    International Nuclear Information System (INIS)

    At the investigation of binary fission reactions one of the main characteristic of process is total kinetic energy (TKE) of fission fragments and it distribution between them. From the values of these characteristics it is possible to extract the information about structure of fission fragments in the break up point of initial fissionable nuclear system. In our work TKE dependence from the deformation parameters of shape and density distribution of charge in the fission fragments are investigated. In the end of paper some generalizations of obtaining results are carried out and presented in the form of tables and figures

  6. Simulation of fission products behavior in severe accidents for advanced passive PWR

    International Nuclear Information System (INIS)

    Highlights: • A fission product analysis model based on thermal hydraulic module is developed. • An assessment method for fission product release and transport is constructed. • Fission products behavior during three modes of containment response is investigated. • Source term results for the three modes of containment response are obtained. - Abstract: Fission product behavior for common Pressurized Water Reactor (PWR) has been studied for many years, and some analytical tools have developed. However, studies specifically on the behavior of fission products related to advanced passive PWR is scarce. In the current study, design characteristics of advanced passive PWR influencing fission product behavior are investigated. An integrated fission products analysis model based on a thermal hydraulic module is developed, and the assessment method for fission products release and transport for advanced passive PWR is constructed. Three modes of containment response are simulated, including intact containment, containment bypass and containment overpressure failure. Fission products release from the core and corium, fission products transport and deposition in the Reactor Coolant System (RCS), fission products transport and deposition in the containment considering fission products retention in the in-containment refueling water storage tank (IRWST) and in the secondary side of steam generators (SGs) are simulated. Source term results of intact containment, containment bypass and containment overpressure failure are obtained, which can be utilized to evaluate the radiological consequences

  7. Study on Fission Blanket Fuel Cycling of a Fusion-Fission Hybrid Energy Generation System

    International Nuclear Information System (INIS)

    Full text: Direct application of ITER-scale tokamak as a neutron driver in a subcritical fusion-fission hybrid reactor to generate electric power is of great potential in predictable future. This paper reports a primary study on neutronic and fuel cycle behaviors of a fission blanket for a new type of fusion-driven system (FDS), namely a subcritical fusion-fission hybrid reactor for electric power generation aiming at energy generation fueled with natural or depleted uranium. Using COUPLE2 developed at INET of Tsinghua University by coupling the MCNP code with the ORIGEN code to study the neutronic behavior and the refueling scheme, this paper focuses on refueling scheme of the fissionable fuel while keeping some important parameters such as tritium breeding ratio (TBR) and energy gain. Different fission fuels, coolants and their volumetric ratios arranged in the fission blanket satisfy the requirements for power generation. The results show that soft neutron spectrum with optimized fuel to moderator ratio can yield an energy amplifying factor of M> 20 while maintaining the TBR > 1.1 and the CR > 1 (the conversion ratio of fissile materials) in a reasonably long refueling cycle. Using an in-site fuel recycle plant, it will be an attractive way to realize the goal of burning 238U with such a new type of fusion-fission hybrid reactor system to generate electric power. (author)

  8. Energy dissipation in the cold fission of 252Cf

    International Nuclear Information System (INIS)

    The conversion of energy of collective nuclear motion into internal single particle excitation energy is one of the modes of nuclear energy dissipation. Dissipation and its relation to pair breaking is one of the challenges in nuclear field. A characteristic of low energy fission is odd-even effect. Odd-even staggering in the mass or charge yields and in the total kinetic energies will be of useful to analyze dissipation energy. The odd even effects in the charge distribution of cold fission fragments can be analysed to extract information on the energy dissipation during the passage from the first potential well towards the scission point through the fission barrier. The Q value during a fission process is decomposed into the total kinetic and excitation energies (TKE and TXE)

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

    OpenAIRE

    Rubchenya V.A.; Gorelov D.; Jokinen A.; Penttilä H.; Äystö J.

    2013-01-01

    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 a...

  10. Fission properties of the BCPM energy-density functional

    International Nuclear Information System (INIS)

    Fission dynamics properties of the Barcelona-Catania-Paris-Madrid energy density functional are explored with mean-field techniques. Potential energy surfaces as well as collective inertia relevant in the fission process are computed for several nuclei where experimental data exist. Inner and outer barrier heights as well as fission isomer excitation energies are reproduced quite well in all the cases. The spontaneous fission half-lives tsf are also computed using the standard semiclassical approach and the results are compared with the experimental data. The experimental trend with mass number is reasonably well reproduced over a range of 27 orders of magnitude. However, the theoretical predictions suffer from large uncertainties when the quantities that enter the spontaneous fission half-life formula are varied. Modifications of only a few per cent in the pairing correlation strengths strongly modify the collective inertia with a large impact on the spontaneous fission lifetimes in all the nuclei considered. Encouraged by the quite satisfactory description of the trend of fission properties with mass number, we explore the fission properties of the even-even uranium isotope chain from 226U to 282U. Very large lifetimes are found beyond A = 256 with a peak at neutron number N = 184.

  11. A Review of Previous Research in Direct Energy Conversion Fission Reactors

    International Nuclear Information System (INIS)

    From the earliest days of power reactor development, direct energy conversion was an obvious choice to produce high efficiency electric power generation. Directly capturing the energy of the fission fragments produced during nuclear fission avoids the intermediate conversion to thermal energy and the efficiency limitations of classical thermodynamics. Efficiencies of more than 80% are possible, independent of operational temperature. Direct energy conversion fission reactors would possess a number of unique characteristics that would make them very attractive for commercial power generation. These reactors would be modular in design with integral power conversion and operate at low pressures and temperatures. They would operate at high efficiency and produce power well suited for long distance transmission. They would feature large safety margins and passively safe design. Ideally suited to production by advanced manufacturing techniques, direct energy conversion fission reactors could be produced more economically than conventional reactor designs. The history of direct energy conversion can be considered as dating back to 1913 when Moseleyl demonstrated that charged particle emission could be used to buildup a voltage. Soon after the successful operation of a nuclear reactor, E.P. Wigner suggested the use of fission fragments for direct energy conversion. Over a decade after Wigner's suggestion, the first theoretical treatment of the conversion of fission fragment kinetic energy into electrical potential appeared in the literature. Over the ten years that followed, a number of researchers investigated various aspects of fission fragment direct energy conversion. Experiments were performed that validated the basic physics of the concept, but a variety of technical challenges limited the efficiencies that were achieved. Most research in direct energy conversion ceased in the US by the late 1960s. Sporadic interest in the concept appears in the literature until this

  12. Nuclear fission energy: the international scene and the outlook for Italy

    International Nuclear Information System (INIS)

    Because of concerns about the environment, energy security and energy costs, fission nuclear energy is gaining ground again around the world. In Italy, the research community can help relaunch the national nuclear programmes by providing advanced training, recruiting young engineers and researchers for RD activities, and furthering an immediate cooperation of the Italian system in the principal European and international projects on sustainable nuclear energy

  13. Considerations for a sustainable nuclear fission energy in Europe

    International Nuclear Information System (INIS)

    Presented is the global energy perspectives and and sustainable development fission vision scenario. Described are the innovative concepts with technological breakthroughs concerning the fuel cycle and evolution of the spent fuel radiotoxic contents

  14. A New Method of Prompt Fission Neutron Energy Spectrum Unfolding

    Science.gov (United States)

    Zeynalova, O. V.; Zeynalov, Sh.; Hambsch, F.-J.; Oberstedt, S.

    2010-11-01

    The prompt neutron emission in spontaneous fission of 252Cf has been investigated applying digital signal electronics along with associated digital signal processing algorithms. The goal was to find out the reasons of a long time existing discrepancy between theoretical calculations and the measurements of prompt fission neutron (PFN) emission dependence on the total kinetic energy (TKE) of fission fragments (FF). On the one hand the 252Cf (sf) reaction is one of the main references for nuclear data, on the other hand the understanding of PFN emission mechanism is very important for nuclear fission theory. Using a twin Frisch-grid ionization chamber for fission fragment (FF) detection and a NE213-equivalent neutron detector in total about 107 fission fragment-neutron coincidences have been registered. Fission fragment kinetic energy, mass and angular distribution, neutron time-of-flight and pulse shape have been investigated using a 12 bit waveform digitizer. The signal waveforms have been analyzed using digital signal processing algorithms. For the first time the dependence of the number of emitted neutrons as a function of total kinetic energy (TKE) of the fragments is in very good agreement with theoretical calculations in the range of TKE from 140-220 MeV.

  15. Fission of Oriented Nuclei by Low Energy Neutrons. RCN Report

    International Nuclear Information System (INIS)

    This report describes the study of the angular distribution of α-particles and of fission fragments originating from neutron capture in heavy nuclei, which are aligned at low temperatures by the method of hyperfine interaction. The results of the measurements with the target nucleus 233U with neutrons in the energy range from 0 to 2000 eV can be interpreted with the Bohr-theory of transition states at the deformation barrier for nuclear fission. The relatively invariant behaviour of the anisotropy in the angular distribution of fission fragments as a function of neutron energy indicates that the available fission channels are strongly mixed. For neutron resonances with spin and parity 2+ 2 to 3 channels are open and for 3+ resonances 1 to 2. The group structure in the subthreshold fission cross section of 237Np has been explained by the double-humped deformation barrier proposed by Strutinsky. The implication of this interpretation is that all the resonances in one group have the same spin. The resonances in the first group at 40 eV agree consistently with the fission channel (2+,2). The groups at higher neutron energies up to 2000 eV correspond mainly with the channels (2+,2) and (3+,2). (author)

  16. Measurement of energy dependence of fission fragment angular anisotropy for resonance neutron induced fission of 235U aligned target

    International Nuclear Information System (INIS)

    The results of the experiment on measuring the energy dependence of fission fragment angular anisotropy in resonance neutron induced fission of 235U aligned target in energy region up to 42 eV are presented. The agreement with the data of Pattenden and Postma in resonances is good enough, while the theoretical curve, calculated using the R-matrix multilevel two fission channel approach, does not seem to describe the energy dependence of fission fragment angular anisotropy property. The necessity of taking into account the interference between levels with different spins is discussed. 11 refs., 2 figs

  17. Implementation in the reaction code system EMPIRE-2.19 of an advanced formalism for fission cross-section calculation

    International Nuclear Information System (INIS)

    Full text: The implementation in the reaction code system EMPIRE-2.19 of an advanced formalism for fission cross-section calculation has been completed. The formalism is based on the optical model for fission and can be applied for nuclei exhibiting double- or triple-humped barrier starting from sub-barrier excitation energies. The optical model for fission, initially developed to describe the resonant structure of the fission cross section at sub-barrier excitation energies due to the vibrational states in the second well of a double-humped fission barrier, was extended to light actinides by including the relations for the transmission coefficients through a complex triple-humped fission barrier. The real part of the fission barrier is parameterised as a function of the nucleus deformation by five smoothly joined parabolas. The imaginary potential is introduced only in the deformation range corresponding to the second well because the tertiary well is supposed to be shallow enough to neglect the damping of class III vibrational states. The transition states are assumed to be rotational states built on vibrational or non-collective band-heads. As the excitation energy increases, the shell effect, which causes the splitting of the outer barrier, diminishes and the outer humps lump into a single one. Therefore, in the present formalism, triple-humped barriers are associated only to the discrete transition states; the contribution of continuum to the fission coefficients is calculated considering a double-humped barrier. The parameters of the second single barrier equivalent with the outer humps are being determined from the condition of equal transmission coefficients. The saddle-point transition states in continuum are described by level densities (BCS below the critical energy and a modified version of Fermi Gas above) accounting for collective enhancements specific to the nuclear shape asymmetry at each saddle point . The neutron cross sections of 232Th in the

  18. 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.

  19. Proton-induced fission of heavy nuclei at intermediate energies

    CERN Document Server

    Deppman, A; Guimaraes, V; Karapetyan, G S; Balabekyan, A R; Demekhina, N A

    2013-01-01

    The intermediate energy proton-induced fission of 241Am, 238$U and 237$Np is studied. The inelastic interactions of protons and heavy nuclei are described by a CRISP model, in which the reaction proceeds in two steps. The first one corresponds fast cascade, where a series of individual particle-particle collisions occurs within the nucleus. It leaves a highly excited cascade residual nucleus, assumed to be in thermal equilibrium. Subsequently, in the second step the excited nucleus releases its energy by evaporation of neutrons and light charged particles as well. Both the symmetric and asymmetric fission are regarded, and the fission probabilities are obtained from CRISP code calculations, by means of statistical weighting factors. The fission cross sections, the fissility of the fissioning nuclei, and the number of nucleons lost by the target - before and after fission - are calculated and compared to experiments for 660 MeV protons incident on 241Am, 238$U and 237$Np. Some of the model predictions are in f...

  20. Establishing a Scientific Basis for Optimizing Compositions, Process Paths and Fabrication Methods for Nanostructured Ferritic Alloys for Use in Advanced Fission Energy Systems

    Energy Technology Data Exchange (ETDEWEB)

    Odette, G Robert; Cunningham, Nicholas J., Wu, Yuan; Etienne, Auriane; Stergar, Erich; Yamamoto, Takuya

    2012-02-21

    lowest Y2O3 concentration of 0.2 wt.%. An APT characterization of MA957 joined by friction stir welding (FSW) showed that this solid sate joining procedure had only a modest effect on the NF number density (N) and average diameter () compared to an as extruded sample. FSW appears to rearrange the NFs, which become highly aligned with sub-boundary and dislocation structures to an extent that are not observed in the as extruded case. The aligned NF structures are less apparent, but seem to persist after post weld annealing at 1150ºC for 3 h following which reduces N, consistent with a significant reduction in hardness. Lastly, several NFA materials, including MA957 and various 14YWT alloys, have been included in irradiation experiments performed at the Advanced Test Reactor, the JOYO sodium cooled fast reactor, the High Flux Isotope Reactor, and the SINQ spallation neut

  1. Early results utilizing high-energy fission product gamma rays to detect fissionable material in cargo

    International Nuclear Information System (INIS)

    Full text: A concept for detecting the presence of special nuclear material (235U or 239Pu) concealed in inter modal cargo containers is described. It is based on interrogation with a pulsed beam of 6-8 MeV neutrons and fission events are identified between beam pulses by their β-delayed neutron emission or β -delayed high-energy γ-radiation. The high-energy γ-ray signature is being employed for the first time. Fission product γ-rays above 3 MeV are distinct from natural radioactivity and from nearly all of the induced activity in a normal cargo. High-energy γ-radiation is nearly 10X more abundant than the delayed neutrons and penetrates even thick cargo's readily. The concept employs two large (8x20 ft) arrays of liquid scintillation detectors that have high efficiency for the detection of both delayed neutrons and delayed γ-radiation. Detector backgrounds and potential interferences with the fission signature radiation have been identified and quantified. This information, together with predicted signature strength, has been applied to the estimation of detection probability for the nuclear material and estimation of false alarm rates. This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48

  2. Perspective on the fusion-fission energy concept

    International Nuclear Information System (INIS)

    A concept which has potential for near-term application in the electric power sector of our energy economy is combining fusion and fission technology. The fusion-fission system, called a hybrid, is distinguished from its pure fusion counterpart by incorporation of fertile materials (uranium or thorium) in the blanket region of a fusion machine. The neutrons produced by the fusion process can be used to generate energy through fission events in the blanket or produce fuel for fission reactors through capture events in the fertile material. The performance requirements of the fusion component of hybrids is perceived as being less stringent than those for pure fusion electric power plants. The performance requirements for the fission component of hybrids is perceived as having been demonstrated or could be demonstrated with a modest investment of research and development funds. This paper presents our insights and observations of this concept in the context of why and where it might fit into the picture of meeting our future energy needs. A bibliography of hybrid research is given

  3. Experimental survey of the potential energy surfaces associated with fission

    International Nuclear Information System (INIS)

    Progress in the experimental determination of the properties of the potential energy surface associated with fission is reviewed. The importance of nuclear symmetry effects on the calculation of fission widths is demonstrated. Evidence is presented for the fragmentation of the mass-asymmetric second barrier in the thorium region and the axial asymmetric first barrier in the californium region. Detailed analyses of experimental data suggest the presence of two parallel second barriers; the normal mass-asymmetric, axial-symmetric barrier and a slightly higher mass-symmetric, axial-asymmetric barrier. Experimental barrier parameters are determined systematically and compared with calculations from various theoretical models. Techniques for expanding fission probability measurements to higher energies are discussed. (author)

  4. Excitation energy dependence of fission in the mercury region

    CERN Document Server

    McDonnell, J D; Sheikh, J A; Staszczak, A; Warda, M

    2014-01-01

    Background: Recent experiments on beta-delayed fission reported an asymmetric mass yield in the neutron-deficient nucleus 180Hg. Earlier experiments in the mass region A=190-200 close to the beta-stability line, using the (p,f) and (\\alpha,f) reactions, observed a more symmetric distribution of fission fragments. While the beta-delayed fission of 180Hg can be associated with relatively low excitation energy, this is not the case for light-ion reactions, which result in warm compound nuclei. Purpose: To elucidate the roles of proton and neutron numbers and excitation energy in determining symmetric and asymmetric fission yields, we compute and analyze the isentropic potential energy surfaces of 174,180,198Hg and 196,210Po. Methods: We use the finite-temperature superfluid nuclear density functional theory, for excitation energies up to E*=30MeV and zero angular momentum. For our theoretical framework, we consider the Skyrme energy density functional SkM* and a density-dependent pairing interaction. Results: Fo...

  5. The Advanced Energy Initiative

    Science.gov (United States)

    Milliken, JoAnn; Joseck, Fred; Wang, Michael; Yuzugullu, Elvin

    The President's Advanced Energy Initiative (AEI), launched in 2006, addresses the challenges of energy supply and demand facing our Nation by supporting research and development of advanced technologies for transportation and stationary power generation. The AEI portfolio includes clean coal, nuclear and renewable energy technologies (solar and wind) for stationary power generation and advanced battery technologies, cellulosic ethanol as a fuel and hydrogen fuel cells for transportation. These research and development programs are underpinned by comprehensive life-cycle analysis efforts using models such as Hydrogen Analysis (H2A) and Greenhouse Gases, Regulated Emissions and Energy Use in Transportation (GREET) to enable a better understanding of the characteristics and trade-offs associated with advanced energy options and to help decision makers choose viable pathways for clean, reliable and affordable energy.

  6. Fragment Deexcitation of Fission Induced by High Energy Nucleons

    OpenAIRE

    Yavshits S.; Grudzevich O.

    2010-01-01

    The KRIF library of the neutron-, proton- and gamma-spectra emitted by the nuclei excited up to 500 MeV is presented. The KRIF contains information for about 2000 emitters which are the fragments of the ten targets fission induced by the nucleons with the energies up to 3 GeV.

  7. Fragment Deexcitation of Fission Induced by High Energy Nucleons

    Directory of Open Access Journals (Sweden)

    Yavshits S.

    2010-03-01

    Full Text Available The KRIF library of the neutron-, proton- and gamma-spectra emitted by the nuclei excited up to 500 MeV is presented. The KRIF contains information for about 2000 emitters which are the fragments of the ten targets fission induced by the nucleons with the energies up to 3 GeV.

  8. Systematics of fission cross sections at the intermediate energy region

    Energy Technology Data Exchange (ETDEWEB)

    Fukahori, Tokio; Chiba, Satoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    The systematics was obtained with fitting experimental data for proton induced fission cross sections of Ag, {sup 181}Ta, {sup 197}Au, {sup 206,207,208}Pb, {sup 209}Bi, {sup 232}Th, {sup 233,235,238}U, {sup 237}Np and {sup 239}Pu above 20 MeV. The low energy cross section of actinoid nuclei is omitted from systematics study, since the cross section has a complicated shape and strongly depends on characteristic of nucleus. The fission cross sections calculated by the systematics are in good agreement with experimental data. (author)

  9. Feasibility of Traveling Wave Direct Energy Conversion of Fission Reaction Fragments

    Science.gov (United States)

    Tarditi, A. G.; George, J. A.; Miley, G. H.; Scott, J. H.

    2013-01-01

    Fission fragment direct energy conversion has been considered in the past for the purpose of increasing nuclear power plant efficiency and for advanced space propulsion. Since the fragments carry electric charge (typically in the order of 20 e) and have 100 MeV-range kinetic energy, techniques utilizing very high-voltage DC electrodes have been considered. This study is focused on a different approach: the kinetic energy of the charged fission fragments is converted into alternating current by means of a traveling wave coupling scheme (Traveling Wave Direct Energy Converter, TWDEC), thereby not requiring the utilization of high voltage technology. A preliminary feasibility analysis of the concept is introduced based on a conceptual level study and on a particle simulation model of the beam dynamics.

  10. High-energy fission models validation and comparison with experiments

    International Nuclear Information System (INIS)

    Calculations including the high energy fission models were performed. Comparisons on BNL-Cosmotron arrangements of thermal neutron peak fluxes in the H2O-moderator for lead and depleted uranium targets are given for different proton beam energies (540, 960, 1470 MeV) and two B0-parameters (8 and 14 MeV) of the level density formula. Preliminary results of neutron spectra measurements for thin uranium targets are compared with HETC calculations at 590 MeV incident proton beam energy. The residual mass distributions are determined in thin uranium targets for proton beam energies of 0.3, 1.0, and 2.9 GeV. The calculations are done using the Rutherford and Appleton Laboratory high energy fission model (RAL) and are compared with respective calculations of the ORNL-model by Alsmiller et al

  11. Simultaneous Measurements of Flight Times and Energies of Fission Fragments

    International Nuclear Information System (INIS)

    In a companion paper the results of measuring the prompt neutron emission from individual fission fragments arising in thermal fission are reported. In that experiment a large volume liquid scintillation counter was .used to. record the fission neutrons, and fragment mass was identified by a gold silicon surface barrier counter.- arrangement. An alternative Way of measuring the prompt neutron emission is described here. Fragment time-of- flight apparatus is mounted in an evacuated tube that passes laterally through the thermal column of the 5-MW research reactor HERALD. A centrally positioned thin source produces 3 x 105 fissions s-1. Fragments travel distances of 180 cm and 300 cm respectively to the terminal detectors, and in passing through a VYNS film, positioned 180 cm from the source along the longer flight path, eject electrons that are used to form a reference time-signal. Essentially the times of flight of both fission fragments are measured simultaneously with the kinetic energy of one of the pair. This is achieved by using a surface barrier counter for the 300-cm detector. The difficulty of maintaining good timing and energy resolutions simultaneously is overcome by routing the pulse to the charge sensitive preamplifier through a delay line amplifier from which a fast timing pulse is derived. The collected data enables the fragment mass to be determined both before and after prompt neutrons have been emitted. Hence the experiment provides a means for studying the behaviour of neutron emission from individual fragments. The experimental uncertainties are those associated with the measurement of small differences, and an appraisal is made of the errors and calibrations that enter into the measurements. Of particular importance, the response of the surface barrier counter to fission fragments is obtained directly, from the collected data from events in which the neutron emission is low. These calibrations are used in the measurements of postneutron mass

  12. Proton-induced fission on 241Am, 238U and 237Np at intermediate energies

    OpenAIRE

    Deppman, A.; Andrade-II, E.; Guimaraes, V; Karapetyan, G. S.; Balabekyan, A. R.; Demekhina, N. A.

    2013-01-01

    Intermediate energy data of proton-induced fission on 241Am, 238U and 237Np targets were analysed and investigated using the computational simulation code CRISP. Inelastic interactions of protons on heavy nuclei and both symmetric and asymmetric fission are regarded. The fission probabilities are obtained from the CRISP code calculations by means of the Bohr-Wheeler model. The fission cross sections, the fissility and the number of nucleons evaporated by the nuclei, before and after fission, ...

  13. Fission of Heavy Elements by High-Energy Protons

    International Nuclear Information System (INIS)

    A brief survey is given of the phenomenology of fission-like break-up processes induced in high-Z elements by protons of high energies, with principal emphasis on the GeV region. Charge dispersions are discussed in some detail. New charge dispersion data in various mass regions for products formed in lead and uranium interactions with 2.9 GeV and 28-GeV protons are reviewed. The pronounced differences between the lead and uranium results are discussed. The doublehumped charge dispersion curves observed near A = 130 for uranium ''fission'' products are interpreted in terms of two different mechanisms, characterized by low and high deposition energies. This interpretation is confirmed by recoil experiments, particularly by data on angular distributions and range spectra for neutron - deficient and neutron-excess products of uranium ''fission''. From the charge dispersions, yield-versus-mass curves for the 2.9-GeV and 28-GeV interactions are constructed and these are compared with the yield-versus - mass distributions at lower energies. In the uranium interactions, a single broad maximum, centred at A ≈ 110, is found in the mass distribution, broader at 28 than at 2.9 GeV. With lead as the target, the mass distribution is flat in the region 40 < A <140. Values of fission cross-sections derived from the yield - versus-mass curves are discussed in the light of fission cross-sections obtained by other methods and at other bombarding energies. (author)

  14. Advanced Computational Materials Science: Application to Fusion and Generation IV Fission Reactors (Workshop Report)

    International Nuclear Information System (INIS)

    The ''Workshop on Advanced Computational Materials Science: Application to Fusion and Generation IV Fission Reactors'' was convened to determine the degree to which an increased effort in modeling and simulation could help bridge the gap between the data that is needed to support the implementation of these advanced nuclear technologies and the data that can be obtained in available experimental facilities. The need to develop materials capable of performing in the severe operating environments expected in fusion and fission (Generation IV) reactors represents a significant challenge in materials science. There is a range of potential Gen-IV fission reactor design concepts and each concept has its own unique demands. Improved economic performance is a major goal of the Gen-IV designs. As a result, most designs call for significantly higher operating temperatures than the current generation of LWRs to obtain higher thermal efficiency. In many cases, the desired operating temperatures rule out the use of the structural alloys employed today. The very high operating temperature (up to 1000 C) associated with the NGNP is a prime example of an attractive new system that will require the development of new structural materials. Fusion power plants represent an even greater challenge to structural materials development and application. The operating temperatures, neutron exposure levels and thermo-mechanical stresses are comparable to or greater than those for proposed Gen-IV fission reactors. In addition, the transmutation products created in the structural materials by the high energy neutrons produced in the DT plasma can profoundly influence the microstructural evolution and mechanical behavior of these materials. Although the workshop addressed issues relevant to both Gen-IV and fusion reactor materials, much of the discussion focused on fusion; the same focus is reflected in this report. Most of the physical models and computational methods presented during the

  15. Excitation-energy sorting in superfluid fission dynamics

    Directory of Open Access Journals (Sweden)

    Schmidt K.-H.

    2010-10-01

    Full Text Available It is now well established that at moderate excitation energies the nucleus temperature does not vary with increasing excitation energy. We show that, as a consequence, two nuclei with different temperatures brought into contact show a rather surprising energy-sorting mechanism where the hotter nucleus transfers all its excitation energy to the colder one. The scission configuration of the fission process offers a unique possibility to observe this phenomenon. The energy-sorting mechanism is clearly reflected by the mean number of prompt neutrons as a function of the fragment mass and by the dependence of the local even-odd effect with mass asymmetry.

  16. Excitation-energy sorting in superfluid fission dynamics

    International Nuclear Information System (INIS)

    It is now well established that at moderate excitation energies the nucleus temperature does not vary with increasing excitation energy. We show that, as a consequence, two nuclei with different temperatures brought into contact show a rather surprising energy-sorting mechanism where the hotter nucleus transfers all its excitation energy to the colder one. The scission configuration of the fission process offers a unique possibility to observe this phenomenon. The energy-sorting mechanism is clearly reflected by the mean number of prompt neutrons as a function of the fragment mass and by the dependence of the local even-odd effect with mass asymmetry. (authors)

  17. Precise Nuclear Data Measurements Possible with the NIFFTE fissionTPC for Advanced Reactor Designs

    Science.gov (United States)

    Towell, Rusty; Niffte Collaboration

    2015-10-01

    The Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) Collaboration has applied the proven technology of Time Projection Chambers (TPC) to the task of precisely measuring fission cross sections. With the NIFFTE fission TPC, precise measurements have been made during the last year at the Los Alamos Neutron Science Center from both U-235 and Pu-239 targets. The exquisite tracking capabilities of this device allow the full reconstruction of charged particles produced by neutron beam induced fissions from a thin central target. The wealth of information gained from this approach will allow systematics to be controlled at the level of 1%. The fissionTPC performance will be presented. These results are critical to the development of advanced uranium-fueled reactors. However, there are clear advantages to developing thorium-fueled reactors such as Liquid Fluoride Thorium Reactors over uranium-fueled reactors. These advantages include improved reactor safety, minimizing radioactive waste, improved reactor efficiency, and enhanced proliferation resistance. The potential for using the fissionTPC to measure needed cross sections important to the development of thorium-fueled reactors will also be discussed.

  18. Performance of the fissionTPC and the Potential to Advance the Thorium Fuel Cycle

    Science.gov (United States)

    Towell, Rusty; Niffte Collaboration

    2014-09-01

    The NIFFTE fission Time Projection Chamber (fissionTPC) is a powerful tool that is being developed to take precision measurements of neutron-induced fission cross sections of transuranic elements. During the last run at the Los Alamos Neutron Science Center (LANSCE) the fully instrumented TPC took data for the first time. The exquisite tracking capabilities of this device allow the full reconstruction of charged particles produced by neutron beam induced fissions from a thin central target. The wealth of information gained from this approach will allow cross section systematics to be controlled at the level of 1%. The fissionTPC performance from this run will be shared. These results are critical to the development of advanced uranium-fueled reactors. However, there are clear advantages to developing thorium-fueled reactors including the abundance of thorium verses uranium, minimizing radioactive waste, improved reactor safety, and enhanced proliferation resistance. The potential for using the fissionTPC to measure needed cross sections important to the development of thorium fueled nuclear reactors will also be discussed.

  19. Comparative evaluation of solar, fission, fusion, and fossil energy resources. Part 2: Power from nuclear fission

    Science.gov (United States)

    Clement, J. D.

    1973-01-01

    Different types of nuclear fission reactors and fissionable materials are compared. Special emphasis is placed upon the environmental impact of such reactors. Graphs and charts comparing reactor facilities in the U. S. are presented.

  20. Composite delayed neutron energy spectra of fissionable isotopes

    International Nuclear Information System (INIS)

    Delayed neutron (DN) energy spectra spanning a range of 0.01-4.00 MeV have been measured for 235U, 238U and 239Pu. DN equilibrium spectra were also measured for all three nuclides. A helium jet transfer system was used to transport fission products to a low-background counting area. Beta-neutron correlations were used for background suppression and for energy determination by the neutron time-of-flight method. The 235U and 239Pu spectra show marked similarity, while those from the fast fission of 238U are considerably more energetic. DN six-group spectra for 235U, 238U and 239Pu have been deduced from these measurements using a constrained least-squares iterative method

  1. Advanced energy materials

    CERN Document Server

    Tiwari, Ashutosh

    2014-01-01

    An essential resource for scientists designing new energy materials for the vast landscape of solar energy conversion as well as materials processing and characterization Based on the new and fundamental research on novel energy materials with tailor-made photonic properties, the role of materials engineering has been to provide much needed support in the development of photovoltaic devices. Advanced Energy Materials offers a unique, state-of-the-art look at the new world of novel energy materials science, shedding light on the subject's vast multi-disciplinary approach The book focuses p

  2. Laser Intertial Fusion Energy: Neutronic Design Aspects of a Hybrid Fusion-Fission Nuclear Energy System

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, Kevin James [Univ. of California, Berkeley, CA (United States)

    2010-04-08

    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 LFFH plants. The LFFH engine described utilizes a central fusion chamber surrounded by multiple layers of multiplying and moderating media. These layers, or blankets, include coolant plenums, a beryllium (Be) multiplier layer, a fertile fission blanket and a graphite-pebble reflector. Each layer is separated by perforated oxide dispersion strengthened (ODS) ferritic steel walls. The central fusion chamber is surrounded by an ODS ferritic steel first wall. The first wall is coated with 250-500 μm of tungsten to mitigate x-ray damage. The first wall is cooled by Li17Pb83 eutectic, chosen for its neutron multiplication and good heat transfer properties. The Li17Pb83 flows in a jacket around the first wall to an extraction plenum. The main coolant injection plenum is immediately behind the Li17Pb83, separated from the Li17Pb83 by a solid ODS wall. This main system coolant is the molten salt flibe (2LiF-BeF2), chosen for beneficial neutronics and heat transfer properties. The use of flibe enables both fusion fuel production (tritium) and neutron moderation and multiplication for the fission blanket. A Be pebble (1 cm diameter) multiplier layer surrounds the coolant injection plenum and the coolant flows radially through perforated walls across the bed. Outside the Be layer, a fission fuel layer comprised of depleted uranium contained in Tristructural-isotropic (TRISO) fuel particles

  3. Laser Intertial Fusion Energy: Neutronic Design Aspects of a Hybrid Fusion-Fission Nuclear Energy System

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, K

    2010-04-08

    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 LFFH plants. The LFFH engine described utilizes a central fusion chamber surrounded by multiple layers of multiplying and moderating media. These layers, or blankets, include coolant plenums, a beryllium (Be) multiplier layer, a fertile fission blanket and a graphite-pebble reflector. Each layer is separated by perforated oxide dispersion strengthened (ODS) ferritic steel walls. The central fusion chamber is surrounded by an ODS ferritic steel first wall. The first wall is coated with 250-500 {micro}m of tungsten to mitigate x-ray damage. The first wall is cooled by Li{sub 17}Pb{sub 83} eutectic, chosen for its neutron multiplication and good heat transfer properties. The {sub 17}Pb{sub 83} flows in a jacket around the first wall to an extraction plenum. The main coolant injection plenum is immediately behind the Li{sub 17}Pb{sub 83}, separated from the Li{sub 17}Pb{sub 83} by a solid ODS wall. This main system coolant is the molten salt flibe (2LiF-BeF{sub 2}), chosen for beneficial neutronics and heat transfer properties. The use of flibe enables both fusion fuel production (tritium) and neutron moderation and multiplication for the fission blanket. A Be pebble (1 cm diameter) multiplier layer surrounds the coolant injection plenum and the coolant flows radially through perforated walls across the bed. Outside the Be layer, a fission fuel layer comprised of depleted uranium contained in Tristructural-isotropic (TRISO) fuel particles having a packing fraction of 20% in 2 cm

  4. Determination of nuclear fission number by high-energy delayed γ-rays

    International Nuclear Information System (INIS)

    Fission numbers of 235U samples irradiated in short time were obtained by fission yield method. The total emission rate of high-energy delayed γ-rays above 3 MeV per fission over time was measured by large volume NaI detector, and high-energy delayed γ-rays emission rate of pulse irradiation was gained. Fission numbers of two 235U samples were obtained by applying the emission rate of high-energy delayed γ-rays per fission, and the relative uncertainty is less than 4%. (authors)

  5. The contrasting fission potential-energy structure of actinides and mercury isotopes

    OpenAIRE

    Ichikawa, Takatoshi; Iwamoto, Akira; Möller, Peter; Sierk, Arnold J.

    2012-01-01

    Fission-fragment mass distributions are asymmetric in fission of typical actinide nuclei for nucleon number $A$ in the range $228 \\lnsim A \\lnsim 258$ and proton number $Z$ in the range $90\\lnsim Z \\lnsim 100$. For somewhat lighter systems it has been observed that fission mass distributions are usually symmetric. However, a recent experiment showed that fission of $^{180}$Hg following electron capture on $^{180}$Tl is asymmetric. We calculate potential-energy surfaces for a typical actinide ...

  6. Theoretical model application to the evaluation of fission neutron data up to 20 MeV incidence energy

    International Nuclear Information System (INIS)

    A complex statistical theory of fission neutron emission combined with a phenomenological fission model has been used to calculate fission neutron data for 238U. Obtained neutron multiplicities and energy spectra as well as average fragment energies for incidence energies from threshold to 20 MeV (including multiple-chance fission) are compared with traditional data representations. (author). 19 refs, 6 figs

  7. Measurement and calculation of the 233Pa fission cross-section for advanced fuel cycles

    International Nuclear Information System (INIS)

    The energy dependence of the neutron-induced fission cross-section of 233Pa has been measured directly for the first time from the fission threshold up to 8.5 MeV. This fission cross-section is a key ingredient in feasibility studies on fast reactors and accelerator driven systems based on the Th-U fuel cycle. The results are at strong variance with the existing evaluations. The new experimental data give lower cross-section values and resolve the question about the threshold energy. Additionally a new theoretical calculation of the reaction cross-section has been performed with the statistical model code STATIS, showing a very good agreement with the experimental data. (authors)

  8. Methodology of a study of correlations between neutron multiplicity, mass and kinetic energy of fission fragments

    International Nuclear Information System (INIS)

    The description of an experimental set-up for the study of the excitation energy distribution of fission fragments by means of coincident measurement of fission neutrons is presented. For every fission event the kinetic energy and mass of both fragments are registered simultaneously with the number of prompt neutrons emitted by each of the complementary fission fragments. With this set-up, the fission fragments are detected by a twin ionization chamber and the neutrons - by two large Gd-loaded liquid scintillator tanks. (author)

  9. Ambiguity in choosing potential energy surface in the interpretation of fission of A∼200 at intermediate excitation energy

    International Nuclear Information System (INIS)

    In order to highlight the sensitivity of the fission observables to the potential energy surface, we have carried out statistical model calculations with three different options: a. liquid drop mass (MLD) and liquid drop fission barrier (BLD), b. experimental mass (Mexp = MLD + Δn) along with a damping of the shell correction at the ground state (Δn) with excitation energy and shell corrected fission barrier (BLD-Δn), c. experimental mass and liquid drop fission barrier

  10. Fission Fragment Mass Distributions and Total Kinetic Energy Release of 235-Uranium and 238-Uranium in Neutron-Induced Fission at Intermediate and Fast Neutron Energies

    Energy Technology Data Exchange (ETDEWEB)

    Duke, Dana Lynn [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-12

    This Ph.D. dissertation describes a measurement of the change in mass distributions and average total kinetic energy (TKE) release with increasing incident neutron energy for fission of 235U and 238U. Although fission was discovered over seventy-five years ago, open questions remain about the physics of the fission process. The energy of the incident neutron, En, changes the division of energy release in the resulting fission fragments, however, the details of energy partitioning remain ambiguous because the nucleus is a many-body quantum system. Creating a full theoretical model is difficult and experimental data to validate existing models are lacking. Additional fission measurements will lead to higher-quality models of the fission process, therefore improving applications such as the development of next-generation nuclear reactors and defense. This work also paves the way for precision experiments such as the Time Projection Chamber (TPC) for fission cross section measurements and the Spectrometer for Ion Determination in Fission (SPIDER) for precision mass yields.

  11. The Power Makers' Challenge And the Need for Fission Energy

    CERN Document Server

    Nicholson, Martin

    2012-01-01

    The Power Makers - the producers of our electricity - must meet the demands of their customers while also addressing the threat of climate change. There are widely differing views about solutions to electricity generation in an emission constrained world. Some see the problem as relatively straight forward, requiring deep cuts in emissions now by improving energy efficiency, energy conservation and using only renewable resources. Many electricity industry engineers and scientists see the problem as being much more involved.   The Power Makers ’ Challenge: and the need for Fission Energy looks at why using only conventional renewable energy sources is not quite as simple as it seems. Following a general introduction to electricity and its distribution, the author quantifies the reductions needed in greenhouse gas emissions from the power sector in the face of ever increasing world demands for electricity. It provides some much needed background on the many energy sources available for producing electricity ...

  12. Design related aspects in advanced nuclear fission plants

    International Nuclear Information System (INIS)

    Important issues to be considered for design of future reactors are: extrapolation of stress rupture data, creep-fatigue, negligible creep, damage monitoring. The paper highlights some new developments taking examples from a martensitic steel (mod 9% Cr), oxide dispersion strengthened (ODS) steels and nickel-base superalloys. Traditional approaches to extrapolation of (thermal) stress rupture data like Larson-Miller Parameter or Monkman-Grant rule seem to be valid concepts also for advanced reactors. However, a significant influence of cyclic softening on creep rates and stress rupture data can be expected as shown for grade 91. This is particularly true for creep-fatigue interactions. Based on cyclic stress-strain behaviour it is also possible to get very good life-time predictions under creep-fatigue with a strain range separation (inelastic fatigue and creep ranges) technique which could replace the currently used linear life fraction rule. Results from in-beam irradiation creep reveal no significant influence of dispersoid size. It can be assumed that irradiation creep is a matrix property. Finally it is shown that micro-sample testing of exposed material could be used as an advanced method for damage assessment in future nuclear power plants.

  13. Design related aspects in advanced nuclear fission plants

    International Nuclear Information System (INIS)

    The construction of nuclear power plants needs design codes (e.g. ASME or RCC-MR) to allow save and reliable design and operation. To meet the requirements of advanced future plants either existing codes have to be amended or new codes have to be developed. Future Generation IV plants like the very high temperature reactor (VHTR) or the sodium fast reactor (SFR) are currently in this stage of code development. Some important issues to be considered in this context are: design curves (lower bound scatter bands), creep-fatigue, negligible creep, crack growth (fatigue, creep, fast fracture), damage monitoring. The paper will provide some insight into the materials problems behind design rules. Examples will be taken from a martensitic steel (mod 9% Cr), oxide dispersion strengthened (ODS) steels and nickel-base superalloys. Possibilities for the replacement of the linear life fraction rule with advanced creep-fatigue damage assessments will be discussed. Specific emphasize will be put on the role of cyclic softening. Damage assessment and propagation of cracks from flaws under creep and fatigue will be touched upon. Some results from creep at low temperatures (irradiation creep, negligible creep) will be presented. (author)

  14. Energy spectra of delayed neutrons from separated fission products. IV

    International Nuclear Information System (INIS)

    Energy spectra of delayed neutrons from the mass-separated fission products 8890Br, 138140I, 142(Xe,Cs) and 144Cs have been measured. Average level spacings, neutron envelopes and Psub(n) values were calculated and compared with the experimental data. The neutron envelopes are well reproduced for all precursors except 90Br and 140I. For the latter the neutron window predicted by various mass formulae is too wide and a considerable reduction was found necessary to bring calculated envelopes in agreement with the experimental distributions. (Auth.)

  15. Role of energy cost in the yield of cold ternary fission of 252Cf

    Indian Academy of Sciences (India)

    P V Kunhikrishnan; K P Santhosh

    2013-01-01

    The energy costs in the cold ternary fission of 252Cf for various light charged particle emission are calculated by includingWong's correction for Coulomb potential. Energy cost is found to be higher in cold fission than in normal fission. It is found that energy cost always increases with decrease in experimental yield in all the light charged particle emissions. The higher ground state deformation of the fragments, the odd–even effect and the enhanced yield in the octupole region observed in cold fission are found to be consistent with the concept of energy cost.

  16. Photo-fission of 232Th and 238U at intermediate energies

    OpenAIRE

    Deppman, A.(Universidade de São Paulo (USP), São Paulo, Brazil); Andrade-II, E.; Guimaraes, V.; Demekhina, N. A.; Karapetyan, G. S.

    2013-01-01

    In this work we present an analysis of the yields of fission fragments induced by bremsstrahlung photons with endpoint energies of 50 and 3500 MeV on 232Th and 238U targets using the simulation code CRISP. A multimodal fission option was added to this code and an extension of the calculation to the properties of the fission products is presented. By dividing the fissioning nuclei according to their fissionability, an approach is introduced which accounts for the contribution of symmetric and ...

  17. Recent measurements with the NIFFTE fission TPC and the potential to advance thorium fuelled reactors

    International Nuclear Information System (INIS)

    The NIFFTE Fission Time Projection Chamber (TPC) is a powerful tool that is being developed to take precision measurements of neutron-induced fission cross sections of transuranic elements. These improved data are needed for many applications including the development of future generations of nuclear reactors. During the last run at the Los Alamos Neutron Science Center (LANSCE) the fully instrumented TPC took data with several different targets for the first time. The exquisite tracking capabilities of this device allow the full reconstruction of charged particles produced by neutron beam induced fissions from a thin central target. The wealth of information gained from this approach will allow cross section systematics to be controlled at the level of 1%. Results from this run will be shared. These results are critical to the development of advanced uranium-fuelled reactors. However, there are clear advantages to developing thorium-fuelled reactors including the abundance of thorium verses uranium, minimizing radioactive waste, improved reactor safety, and enhanced proliferation resistance. The potential for using the NIFFTE fission TPC to measure needed cross sections important to the development of thorium fuelled nuclear reactors will also be discussed. (author)

  18. Neutron and fragment yields in proton-induced fission of 238U at intermediate energies

    International Nuclear Information System (INIS)

    The primary fission fragment mass and kinetic energy distributions, and neutron multiplicities as function of fragment mass have been measured in the proton-induced fission of 238U at energies Ep=20, 35, 50 and 60 MeV using time-of-flight technique. Pre-scission and post-scission neutron multiplicities have been extracted from double differential distributions. The fragment mass dependence of the post-scission neutron multiplicities reveals the gross nuclear shell structure effect even at the higher proton energies we measured. The yields of neutron-rich fission products in the fission of 238U by 25 MeV protons were measured using an ion guide-based isotope separator technique. The results indicate enhancement for superasymmetric mass division at intermediate excitation energy of the fissioning nucleus. The experimental results have been analysed in the framework of a time-dependent statistical model with inclusion of nuclear friction effects in the fission process

  19. EU Energy Strategy and The Role of Fission Energy

    International Nuclear Information System (INIS)

    European Council in its conclusions of 8/9 March 2007 endorsed conditionally as EU objective a 30 percent reduction of GHG emission by 2020 compared to 1990 with a firm commitment to achieve at least 20 percent reduction. Further commitments are reduction of energy consumption by 20 percent compared with projections for 2020 and a 20 percent share of renewable energy sources in overall energy consumption in 2020. Assuming that the reduction of energy consumption by 20 percent relative to projections for 2020, is achieved, as well as increase of renewable in total energy consumption from 4.4 percent share in 1990 to 20 percent in 2020, and provided that nuclear contribution is not reduced, then the CO2 emission reduction target of 20 percent by 2020 relative to 1990 could be attained. However, both these commitments on consumption decrease and share of renewable in 2007 EC conclusions are in comparison with the 2006 Green Paper so ambitious that reserve measures should be considered. The 2006 Green Paper projected an increase of a share of renewable in total energy production to 12.2 percent by 2030. According to IEA World Energy Outlook 2004 projections, used in Green Paper, wind power would in 2030 contribute with 11 percent in electricity production, on the level of 480 TWh. This projection would require installed wind power of 170 to 180 GW. With new, considerably higher target for renewable by 2020 and limited scope for hydro and solar power increase, wind power would probably have to be increased by at least 50 percent, to about 250-270 GW, to bring renewable share to the 20 percent in overall energy consumption. At present installed wind power in EC amounts to about 50 GW, so to reach a 20 percent target for renewable by 2020 over 200 GW of new wind power would have to be built in not much more than 10 years, unless some spectacular advance with solar energy. Assuming that mass installations start by 2010 the required annual construction would be about 20 GW

  20. Fragment-mass distributions in fission of heavy nuclei by intermediate and high-energy probes

    Energy Technology Data Exchange (ETDEWEB)

    Deppman, Airton; Andrade-II, E. [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica; Menezes, J.C.M.; Garcia, F. [Universidade Estadual de Santa Cruz (UESC), Ilheus, BA (Brazil); Duarte, S.B.; Tavares, O.A.P. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Rossi, P.C.R. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Full text: Recent experiments have shown that the multimode approach for describing the fission process leads to some compatibility with the observed results. A systematic analysis of the parameters obtained by fitting the fission-fragment mass distribution to the spontaneous and low-energy data has shown that the values for those parameters present a smooth dependence upon the nuclear mass number. In the present work it is shown that the same parameter-values obtained for low- energy fission can be used to describe high-energy fission results of fragment-mass distributions if one takes into account the appropriate distribution of the fissioning system. To calculate the fission-fragment mass distributions, Monte Carlo simulations are used. This simulation considers a two-step reaction mechanism, namely, an intranuclear cascade providing the compound nucleus followed by a mechanism of competition between particle evaporation and fission. The fission-fragment masses are obtained according to the multimode approach following the Statistical Scission Model. Simulations for fission induced by 660 MeV protons on 241Am and 237Np, and for fission of 238U induced by photons from Bremsstrahlung with end-point energies of 50 MeV and 3500 MeV have been performed, and the results have been compared with recent experimental data. (author)

  1. Dynamical effects in fission investigated at high excitation energy

    OpenAIRE

    Benlliure J.

    2016-01-01

    The experimental techniques used for the investigation of nuclear fission have progressed considerably during the last decade. Most of this progress is based on the use of the inverse kinematics technique allowing for the first time the complete isotopic and kinematic characterization of both fission fragments. These measurements make possible to characterize the fissioning system at saddle and at scission, and can be used to benchmark fission model calculations. One of the important ingredie...

  2. Simultaneous Velocity and Energy Measurement of Fission Fragments

    International Nuclear Information System (INIS)

    Semi-conductor detectors have been used in a double-velocity apparatus for a simultaneous measurement of fragment velocities and detector pulse heights. The purposes of this measurement were (1) to obtain the pulse-height-to-energy calibration of these detectors for fission fragments and (2) to evaluate a technique for the simultaneous determination of pre- and post neutron emission parameters of the fission process from a coincident measurement of fragment velocities and energies. Fast and slow output signals were obtained from the detectors for use in the time-of-flight and pulse-height measurements respectively. The recorded data were the flight times of both fragments and the pulse height from one of the detectors for a total of 46 000 Cf252 fission events. Fragment velocities, initial masses and initial energies were obtained in the usual manner from the time-of- flight data. The detector calibration function was determined from the correlation between the recorded pulse heights and the final parameters of the corresponding fragments. The latter values were obtained from the initial mass, initial energy and the published values of v(m, EK) for californium fragments. Finally, the calibration function was corrected for instrumental dispersions and the dependence of the average energy on fragment mass. The post-neutron-emission parameters were obtained from the recorded data and available detector calibration procedures including the one given above. The average number of neutrons emitted as.a function of fragment mass was obtained from the event-by-event differences of the initial and final masses. This result provided a sensitive test of the validity of this proposed technique and the various calibration procedures. Agreement with published data was found for the calibration procedure based on these data and one derived from the response of semi-conductor detectors to accelerated bromine and iodine ions. In each case the root mean square deviation from the

  3. Understanding Low Energy Gamma Emission from Fission and Capture with DANCE

    Science.gov (United States)

    Wilburn, Grey; Couture, Aaron; Mosby, Shea

    2012-10-01

    Los Alamos National Laboratory's Detector for Advanced Neutron Capture Experiments (DANCE) consists of 160 barium fluoride (BaF2) detectors in a 4π array used to study cross-section measurements from neutron capture reactions. Further, recent studies have taken advantage of DANCE to study the gamma emission from fission, which is not well characterized. Neutron capture is studied because of its relevance to nuclear astrophysics (almost all elements heavier than iron are formed via neutron capture) and nuclear energy, where neutron capture is a poison in the reactor. Gamma ray cascades following neutron capture and fission include photons with energies between 100 keV and 10 MeV. DANCE uses a ^6LiH sphere to attenuate scattered neutrons, the primary background in DANCE. Unfortunately, it also attenuates low energy gamma rays. In order to quantify this effect and validate simulations, direct measurements of low energy gammas were made with a high purity germanium (HPGe) crystal. HPGe's allow for high resolution measurements of low energy gamma rays that are not possible using the BaF2 crystals. The results and their agreement with simulations will be discussed.

  4. Fission cross section calculations for 209Bi target nucleus based on fission reaction models in high energy regions

    Directory of Open Access Journals (Sweden)

    Kaplan Abdullah

    2015-01-01

    Full Text Available Implementation of projects of new generation nuclear power plants requires the solving of material science and technological issues in developing of reactor materials. Melts of heavy metals (Pb, Bi and Pb-Bi due to their nuclear and thermophysical properties, are the candidate coolants for fast reactors and accelerator-driven systems (ADS. In this study, α, γ, p, n and 3He induced fission cross section calculations for 209Bi target nucleus at high-energy regions for (α,f, (γ,f, (p,f, (n,f and (3He,f reactions have been investigated using different fission reaction models. Mamdouh Table, Sierk, Rotating Liquid Drop and Fission Path models of theoretical fission barriers of TALYS 1.6 code have been used for the fission cross section calculations. The calculated results have been compared with the experimental data taken from the EXFOR database. TALYS 1.6 Sierk model calculations exhibit generally good agreement with the experimental measurements for all reactions used in this study.

  5. Ternary Fission

    International Nuclear Information System (INIS)

    The fission process in which heavy nuclei fragment into three large charged panicles, in place of the usual two, has been studied in the case of thermal-neutron-induced fission of U235 and the spontaneous fission of Cf252. Solid-state detectors, a fast triple coincidence system and a three-coincident-parameter analyser were used to measure the three fission fragment energies parallel with the detection of each ternary fission event. Experimental evidence is presented supporting the existence of ternary fission by specifically excluding recoil phenomena and accidental events as contributing to the observed three-fold coincidence events. Mass-energy-angular correlations of ternary fission have been determined and are summarized as follows: The total kinetic energy release in ternary fission appears to be slightly higher (by approximately 10 MeV) than that for binary fission. In the case of the spontaneous ternary fission of Cf252, the frequency of occurrence is observed to be greater than 2.2 x 10-6 ternary fission events per binary fission event. Tripartition of Cf252 results preferentially in division into two medium mass particle (one of which has a mass number near 56) and one larger mass. In the case of thermal-neutron-induced fission of U235, the frequency of occurrence is observed to be greater than 1.2 x 10-6 ternary fission events per binary fission event. Ternary fission of U236: results in the formation of one light fragment (near mass 36) and two large fragments or, as in the case of Cf252, two medium fragments and one large one. These results indicate that axially asymmetric distortion modes are possible in the pre-scission configurations of the fissioning nucleus. A description is given of experiments designed to radiochemically detect the light fragment resulting from ternary fission. (author)

  6. Economic implications of fusion-fission energy systems

    International Nuclear Information System (INIS)

    The principal conclusions that can be made based on the estimated costs reported in this paper are twofold. First, hybrid reactors operating symbiotically with conventional fission reactors are a potentially attractive supply alternative. Estimated hybrid energy system costs are slightly greater than estimated costs of the most attractive alternatives. However, given the technological, economic, and institutional uncertainties associated with future energy supply, differences of such magnitude are of little significance. Second, to be economically viable, hybrid reactors must be both fuel producers and electricity producers. A data point representing each hybrid reactor driver-blanket concept is plotted as a function of net electrical production efficiency and annual fuel production. The plots illustrate that the most economically viable reactor concepts are those that produce both fuel and electricity

  7. Dynamical effects and fission in the heavy ion collisions at incident energies near the Fermi energy

    International Nuclear Information System (INIS)

    In this work we have studied the reaction mechanisms implied in the heavy ion collisions at energies near the Fermi level. We have observed the predominance of binary processes (2 principal nuclei in the exit channel) and selected events leading to the fission of one of the two fragmentation products. On the basis of the study of angular distributions of fission fragments and associated light particles, we have determined the angular momentum of the nucleus in the moment of fission and the angular momentum transfer in the interaction. The comparison of experimental values of the angular momentum transferred with the theoretical models enables the characterization of projectile-target interaction. For the different systems studied, the spin of fissioning nucleus ranges between 30 ℎ and 60 ℎ while the transferred angular momentum may reach 90 ℎ. For these studies the determinant parameter is the sequence of emission of light particles and fragments, hence the lifetime associated to each processes. For central collisions we have measured pre-fission lifetimes lower then 10-21 sec. These values are very short in comparison with the statistical fission processes, what prompted to search for off-equilibrium (non-statistical) phenomena in the data. Taking into account the charges of the fission fragments we were able to isolate a dynamical component and a statistical component in the fission process. We have compared these two classes of events and showed that there is a relative excess of energy between the fragments when the origin of scission is dynamical. We hope to derive of this observable the nuclear deformation velocity and constrain the value of the nuclear matter viscosity in comparison with the theoretical models

  8. 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.

  9. The Future of Nuclear Energy: Facts and Fiction Chapter I: Nuclear Fission Energy Today

    OpenAIRE

    Dittmar, Michael

    2009-01-01

    Nuclear fission energy is considered to be somewhere between the holy grail, required to solve all energy worries of the human industrialized civilization, and a fast path directly to hell. Discussions about future energy sources and the possible contribution from nuclear energy are often dominated by variations of fundamentalists and often irrational approaches. As a result, very little is known by the general public and even by decision makers about the contribution of nuclear energy today,...

  10. Dependence of Fission-Fragment Properties On Excitation Energy For Neutron-Rich Actinides

    Science.gov (United States)

    Ramos, D.; Rodríguez-Tajes, C.; Caamaño, M.; Farget, F.; Audouin, L.; Benlliure, J.; Casarejos, E.; Clement, E.; Cortina, D.; Delaune, O.; Derkx, X.; Dijon, A.; Doré, D.; Fernández-Domínguez, B.; de France, G.; Heinz, A.; Jacquot, B.; Navin, A.; Paradela, C.; Rejmund, M.; Roger, T.; Salsac, M. D.; Schmitt, C.

    2016-03-01

    Experimental access to full isotopic fragment distributions is very important to determine the features of the fission process. However, the isotopic identification of fission fragments has been, in the past, partial and scarce. A solution based on the use of inverse kinematics to study transfer-induced fission of exotic actinides was carried out at GANIL, resulting in the first experiment accessing the full identification of a collection of fissioning systems and their corresponding fission fragment distribution. In these experiments, a 238U beam at 6.14 AMeV impinged on a carbon target to produce fissioning systems from U to Am by transfer reactions, and Cf by fusion reactions. 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.

  11. Preliminary calculations of medium-energy fission cross sections and spectra

    International Nuclear Information System (INIS)

    Nucleon-induced fission cross sections determined from a statistical preequilibrium model are used in conjunction with a new scission-point model of fission fragment mass, charge and excitation energy distributions to produce evaporation model calculations of particle and gamma spectra and multiplicities from fission. Comparisons are made to experiment for the 14.5-MeV neutron-induced fission of 238U. In addition, calculated particle and gamma spectra will be compared with the ENDF/B library for 2- and 5-MeV neutron-induced fission of 235U and 238U, respectively. Initial predictions for these same quantities for proton-induced fission reactions at energies up to 100 MeV will be presented and discussed. 6 refs., 3 figs

  12. Benchmarking Nuclear Fission Theory

    OpenAIRE

    G. F. Bertsch(INT, Seattle, USA); Loveland, W.; Nazarewicz, W.; Talou, P.

    2015-01-01

    We suggest a small set of fission observables to be used as test cases for validation of theoretical calculations. The purpose is to provide common data to facilitate the comparison of different fission theories and models. The proposed observables are chosen from fission barriers, spontaneous fission lifetimes, fission yield characteristics, and fission isomer excitation energies.

  13. Neutron energy distributions in the dynamical competition between evaporation and fission

    International Nuclear Information System (INIS)

    So far theoretical investigations on the abnormal emission of light particles in competition with fission have dealt only with the total number of emitted particles. In this study, a first step in calculations of energy spectra is attempted in the framework of transport equation describing the evolution of an excited nucleus toward fission. We stress the role of differential multiplicities as qualified strobes to gain knowledge on the dynamical evolution of the fission process

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

    International Nuclear Information System (INIS)

    Fission-product decay energy-releases rates were measured for thermal-neutron fission of 235U. Samples of mass 1 to 10 μg 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 γ/) vs E/sub γ/ and N(E/sub beta/) vs E/sub β/. 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 γ/ and E/sub β/ 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

  15. The fusion fission and quasi-fission processes in the reaction 48Ca + 208Pb at energies near the Coulomb barrier

    Science.gov (United States)

    Prokhorova, E. V.; Bogachev, A. A.; Itkis, M. G.; Itkis, I. M.; Knyazheva, G. N.; Kondratiev, N. A.; Kozulin, E. M.; Krupa, L.; Oganessian, Yu. Ts.; Pokrovsky, I. V.; Pashkevich, V. V.; Rusanov, A. Ya.

    2008-04-01

    Mass-energy distributions (MEDs) and capture-fission cross sections have been measured in the reaction 48Ca + 208Pb → 256No at the energies E=206-242 MeV using a double-arm time-of-flight spectrometer CORSET. It has been observed that MED of the fragments consists of two parts, namely, the classical fusion-fission process corresponding to the symmetric fission of 256No and quasi-fission "shoulders" corresponding to the light fragment masses ˜60-90 u and complimentary heavy fragment masses. The quasi-fission "shoulders" have a higher total kinetic energy (TKE) as compared with that expected for the classical fission. A mathematical formalism was employed for the MEDs fragment decomposition into fusion-fission and quasi-fission components. In the fusion-fission process a high-energy Super-Short mode has been discovered for the masses M=130-135 u and the TKE of ≈233 MeV.

  16. The fusion-fission and quasi-fission processes in the reaction 48Ca + 208Pb at energies near the Coulomb barrier

    International Nuclear Information System (INIS)

    Mass-energy distributions (MEDs) and capture-fission cross sections have been measured in the reaction 48Ca + 208Pb →256No at the energies Elab=206-242 MeV using a double-arm time-of-flight spectrometer CORSET. It has been observed that MED of the fragments consists of two parts, namely, the classical fusion-fission process corresponding to the symmetric fission of 256No and quasi-fission 'shoulders' corresponding to the light fragment masses ∼60-90 u and complimentary heavy fragment masses. The quasi-fission 'shoulders' have a higher total kinetic energy (TKE) as compared with that expected for the classical fission. A mathematical formalism was employed for the MEDs fragment decomposition into fusion-fission and quasi-fission components. In the fusion-fission process a high-energy Super-Short mode has been discovered for the masses MH=130-135 u and the TKE of ∼233 MeV

  17. Channel Effects in the Kinetic Energy of Fragments of Fission Induced by Low-Energy Resonance Neutrons

    International Nuclear Information System (INIS)

    Recently, Blyumkina et al. have noted tfte existence ot fission channel ettects in the total kinetic energy of fragments of fission induced by s- and p-wave neutrons. Effects of this nature can also be expected in the variation of the fragment kinetic energies from resonance to resonance in low-energy (s-wave) neutron-induced fission. A fission-fragment detector whose efficiency is dependent on the kinetic energy of the fragments was used in the study of the slow-neutron-induced fission of U235. Comparing the counting-rate of this detector with a conventional fission detector, whose efficiency is independent of the fragment kinetic energy, shows that there exists a variation in the kinetic energy of certain fragments with neutron energy in the neutron energy region from 0.025 to 1 eV. In order to determine the response of the kinetic-energy-sensitive detector, it was necessary to measure the rangè-energy relations of fission fragments in various media, including noble gases and metallic foils. It was estimated from these data that the variation in the fragment kinetic energy release is ∼500 keV, for those fission events that give the lightest and most energetic of the heavy fragments. The variation in fragment kinetic energy is strongly asymmetric about the 0.28-eV resonance in U235, and suggests that the fragment kinetic energy sensitively reflects the presence of interference effects among resonances in fission. A multi-level multi-channel analysis of the data has been made, based on the parameters of Vogt and under the assumption that different fission channels lead to different configurations at scission, such that the kinetic energy release is also different. Previously a major objection to multi-level multi-channel analysis in fission has been that the parameters obtained are not unique. However, the possibility of observing partial fission cross-sections (fission occurring by way of one channel only) removes one of the ambiguities inherent in the multi

  18. An investigation of fission models for high-energy radiation transport calculations

    International Nuclear Information System (INIS)

    An investigation of high-energy fission models for use in the HETC code has been made. The validation work has been directed checking the accuracy of the high-energy radiation transport computer code HETC to investigate the appropriate model for routine calculations, particularly for spallation neutron source applications. Model calculations are given in terms of neutron production, fission fragment energy release, and residual nuclei production for high-energy protons incident on thin uranium targets. The effect of the fission models on neutron production from thick uranium targets is also shown. (orig.)

  19. FITPULS: a code for obtaining analytic fits to aggregate fission-product decay-energy spectra

    International Nuclear Information System (INIS)

    The operation and input to the FITPULS code, recently updated to utilize interactive graphics, are described. The code is designed to retrieve data from a library containing aggregate fine-group spectra (150 energy groups) from fission products, collapse the data to few groups (up to 25), and fit the resulting spectra along the cooling time axis with a linear combination of exponential functions. Also given in this report are useful results for aggregate gamma and beta spectra from the decay of fission products released from 235U irradiated with a pulse (10-4 s irradiation time) of thermal neutrons. These fits are given in 22 energy groups that are the first 22 groups of the LASL 25-group decay-energy group structure, and the data are expressed both as MeV per fission second and particles per fission second; these pulse functions are readily folded into finite fission histories. 65 figures, 11 tables

  20. 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.

  1. Description of Induced Nuclear Fission with Skyrme Energy Functionals: I. Static Potential Energy Surfaces and Fission Fragment Properties

    OpenAIRE

    Schunck, N.; Duke, DJ; Carr, H.; Knoll, A

    2013-01-01

    Eighty years after its experimental discovery, a description of induced nuclear fission based solely on the interactions between neutrons and protons and quantum many-body methods still poses formidable challenges. The goal of this paper is to contribute to the development of a predictive microscopic framework for the accurate calculation of static properties of fission fragments for hot fission and thermal or slow neutrons. To this end, we focus on the Pu239(n,f) reaction and employ nuclear ...

  2. Fission energy program of the U. S. Department of Energy

    Energy Technology Data Exchange (ETDEWEB)

    1978-06-01

    The document describes programs managed by the Program Director for Nuclear Energy, Department of Energy, and under the cognizance of the Committee on Science and Technology, United States House of Representatives. The major portion of the document is concerned with civilian nuclear power development, the policy for which has been established by the National Energy Plan of April 1977, but it also includes descriptions of the space applications and naval reactor programs.

  3. Measurement of fission cross-section of actinides at n_TOF for advanced nuclear reactors

    CERN Document Server

    Calviani, Marco; Montagnoli, G; Mastinu, P

    2009-01-01

    The subject of this thesis is the determination of high accuracy neutron-induced fission cross-sections of various isotopes - all of which radioactive - of interest for emerging nuclear technologies. The measurements had been performed at the CERN neutron time-of-flight facility n TOF. In particular, in this work, fission cross-sections on 233U, the main fissile isotope of the Th/U fuel cycle, and on the minor actinides 241Am, 243Am and 245Cm have been analyzed. Data on these isotopes are requested for the feasibility study of innovative nuclear systems (ADS and Generation IV reactors) currently being considered for energy production and radioactive waste transmutation. The measurements have been performed with a high performance Fast Ionization Chamber (FIC), in conjunction with an innovative data acquisition system based on Flash-ADCs. The first step in the analysis has been the reconstruction of the digitized signals, in order to extract the information required for the discrimination between fission fragm...

  4. Nuclear energy and fusion-fission hybrid reactor for pure energy production

    International Nuclear Information System (INIS)

    The next two decades are very critical for nuclear energy development. The commercial fast reactor may be in use around 2035; it is also possible that magnetically confined fusion, laser fusion and z-pinch fusion will be demonstrated at that time. A fusion demonstration reactor can be a pure fusion or a fusion-fission hybrid. The latter can lower the fusion power and mitigate the radiation damage of high energy neutrons to materials. On the other hand, the supply of deuterium and tritium as fuel for fusion can only last a few hundred years. We describe here a hybrid for pure energy use which can make full use of uranium and is proliferation resistant, as no separation of uranium and plutonium is needed in post-processing. The union of fission, fusion, and a pure energy hybrid can contribute to the large scale use of nuclear energy in the near future, and supply mankind for more than a thousand years. (authors)

  5. Fission energy program of the U.S. Department of Energy. FY 1980

    International Nuclear Information System (INIS)

    This document presents the baseline implementation program plan as of January 1979 and is derived from the National Energy Plan and other major policy documents. The document discusses civilian nuclear power development, the policy for which has been established by the National Energy Plan of April 1977 and the National Energy Act of 1978. It derives the fission energy policy and program objectives from the National Energy Plan and Act, describes the overall program strategy, and presents the overall budget. The approach used in managing the program, including the program structure and methods used for program control, is explained. The civilian fission power development implementation programs are described in detail. Other considerations affecting civilian nuclear power development are also discussed

  6. Fission properties of actinide nuclei from proton-induced fission at 26.5 and 62.9 MeV incident proton energies

    OpenAIRE

    Demetriou, P.; Keutgen, Thomas; Prieels, René; El Masri, Youssef

    2010-01-01

    Fission properties of proton-induced fission on Th232, Np237, U238, Pu239, and Am241 targets, measured at the Louvain-la-Neuve cyclotron facility at proton energies of 26.5 and 62.9 MeV, are compared with the predictions of the state-of-the-art nuclear reaction code talys. The code couples the multimodal random neck-rupture model with the pre-equilibrium exciton and statistical models to predict fission fragment mass yields, pre- and post-scission neutron multiplicities, and total fission cro...

  7. Photon and proton induced fission on heavy nuclei at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Andrade-II, E.; Karapetyan, G.S.; Deppman, A.; Guimaraes, V. [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Fisica; Balabekyan, A.R. [Yerevan State University, Alex Manoogian 1, Yerevan (Armenia); Demekhina, N.A. [Yerevan Physics Institute, Alikhanyan Brothers 2, Yerevan (Armenia); Joint Institute for Nuclear Research (JINR), Flerov Laboratory of Nuclear Reactions (LNR), Moscow (Russian Federation)

    2014-07-01

    We present an analysis of fission induced by intermediate energy protons or photons on actinides. The 660 MeV proton induced reactions are on {sup 241}Am, {sup 238}U, and {sup 237}Np targets and the Bremsstrahlung-photons with end-point energies at 50 MeV and 3500 MeV are on {sup 232}Th and {sup 238}U targets. The study was performed by means of the Monte Carlo simulation code CRISP. A multimodal fission extension was added to the code within an approach which accounts for the contribution of symmetric and asymmetric fission. This procedure allowed the investigation of fission cross sections, fissility, number of evaporated nucleons and fission-fragment charge distributions. The comparison with experimental data show a good agreement between calculations and experiments. (author)

  8. Photon and proton induced fission on heavy nuclei at intermediate energies

    Directory of Open Access Journals (Sweden)

    Andrade-II E.

    2014-04-01

    Full Text Available We present an analysis of fission induced by intermediate energy protons or photons on actinides. The 660 MeV proton induced reactions are on 241Am, 238U, and 237Np targets and the Bremmstrahlung-photons with end-point energies at 50 MeV and 3500 MeV are on 232Th and 238U targets. The study was performed by means of the Monte Carlo simulation code CRISP. A multimodal fission extension was added to the code within an approach which accounts for the contribution of symmetric and asymmetric fission. This procedure allowed the investigation of fission cross sections, fissility, number of evaporated nucleons and fission-fragment charge distributions. The comparison with experimental data show a good agreement between calculations and experiments.

  9. Photon and proton induced fission on heavy nuclei at intermediate energies

    International Nuclear Information System (INIS)

    We present an analysis of fission induced by intermediate energy protons or photons on actinides. The 660 MeV proton induced reactions are on 241Am, 238U, and 237Np targets and the Bremsstrahlung-photons with end-point energies at 50 MeV and 3500 MeV are on 232Th and 238U targets. The study was performed by means of the Monte Carlo simulation code CRISP. A multimodal fission extension was added to the code within an approach which accounts for the contribution of symmetric and asymmetric fission. This procedure allowed the investigation of fission cross sections, fissility, number of evaporated nucleons and fission-fragment charge distributions. The comparison with experimental data show a good agreement between calculations and experiments. (author)

  10. Nuclear fission

    International Nuclear Information System (INIS)

    V.M. STRUTINSKY's semi-classical method is the most precise to determine the energy of the different states along the fission way. The double-humped fission barrier explains fission isomerism. V.M. STRUTINSKY's barrier explains the ''intermediate structure'' observed in the cross section under the threshold; it provides also the observed effect of ''vibrational resonances'' with an interpretation. Taking an asymmetry parameter in consideration, a triple-humped fission barrier seems to be essential now for the light actinides. There is still a microscopic fission barrier to be explained

  11. Description of Induced Nuclear Fission with Skyrme Energy Functionals: II. Finite Temperature Effects

    OpenAIRE

    Schunck, N.; Duke, DJ; Carr, H.

    2013-01-01

    Understanding the mechanisms of induced nuclear fission for a broad range of neutron energies could help resolve fundamental science issues, such as the formation of elements in the universe, but could have also a large impact on societal applications in energy production or nuclear waste management. The goal of this paper is to set up the foundations of a microscopic theory to study the static aspects of induced fission as a function of the excitation energy of the incident neutron, from the...

  12. Multi-mode fission mechanisms correlated to deformation of the fragments and transition of the characteristics in relation to excitation energy of the fissioning system

    International Nuclear Information System (INIS)

    Aiming to conduct a measurement under further higher resolution, a TOF measurement of the fission fragment of 235U(nth,f) was conducted by using a thin-film scintillator excellent in time responsibility. By TOF measurement, the fission fragment mass after emitting the prompt neutron and the numbers of the prompt neutron could be obtained. And, double energy measurement at the different incident proton energy was conducted for 238U(p,f) to investigate the to investigate the energy dependency of the nuclear fission. As a result of investigating the nuclear fission mechanism in multi face and due to the obtained data, it was found that degree of deformation of the fission fragment played an important role. However, as data on the prompt neutron numbers was not obtained this time, more detailed investigation could not be conducted. (G.K.)

  13. Multi-mode fission mechanisms correlated to deformation of the fragments and transition of the characteristics in relation to excitation energy of the fissioning system

    Energy Technology Data Exchange (ETDEWEB)

    Takamiya, Koichi; Inoue, Takakazu; Nakanishi, Kiyoshi [Osaka Univ., Toyonaka (Japan). Faculty of Science] [and others

    1997-03-01

    Aiming to conduct a measurement under further higher resolution, a TOF measurement of the fission fragment of {sup 235}U(n{sub th},f) was conducted by using a thin-film scintillator excellent in time responsibility. By TOF measurement, the fission fragment mass after emitting the prompt neutron and the numbers of the prompt neutron could be obtained. And, double energy measurement at the different incident proton energy was conducted for {sup 238}U(p,f) to investigate the to investigate the energy dependency of the nuclear fission. As a result of investigating the nuclear fission mechanism in multi face and due to the obtained data, it was found that degree of deformation of the fission fragment played an important role. However, as data on the prompt neutron numbers was not obtained this time, more detailed investigation could not be conducted. (G.K.)

  14. A comparison of fusion breeder/fission client and fission breeder/fission client systems for electrical energy production

    International Nuclear Information System (INIS)

    A parametric study that evaluated the economic performance of breeder/client systems is described. The linkage of the breeders to the clients was modelled using the stockpile approach to determine the system doubling time. Since the actual capital costs of the breeders are uncertain, a precise prediction of the cost of a breeder was not attempted. Instead, the breakeven capital cost of a breeder relative to the capital cost of a client reactor was established by equating the cost of electricity from the breeder/client system to the cost of a system consisting of clients alone. Specific results are presented for two breeder/client systems. The first consisted of an LMFBR with LWR clients. The second consisted of a DT fusion reactor (with a 238U fission suppressed blanket) with LWR clients. The economics of each system was studied as a function of the cost of fissile fuel from a conventional source. Generally, the LMFBR/LWR system achieved relatively small breakeven capital cost ratios; the maximum ratio computed was 2.2 (achieved at approximately triple current conventional fissile material cost). The DTFR/LWR system attained a maximum breakeven capital cost ratio of 4.5 (achieved at the highest plasma quality (ignited device) and triple conventional fissile cost)

  15. Safety and economical requirements of conceptual fusion power reactors in co-existing advanced fission plants

    International Nuclear Information System (INIS)

    An EPR fission plant is expected to operate from 2010 to 2070. In this time range a new generation of advanced fission reactors and several stages of fusion reactors from ITER to DEMO will emerge. Their viability in the competitive socio-economic environment and also their possible synergy benefits are discussed in this paper. The studied cases involve the Finnish EPR, Generation IV, and the EFDA Power Plant Conceptual Study Models A-D. The main focus is on economic and safety assessments. Some cross-cutting issues of technologies are discussed. Concerning the economic potential of both conceptual fusion power plants and those of Generation IV candidates, we have used the present Finnish EPR as a reference. Comparisons using various pricing methods are made for fusion and Generation IV: mass flow analyses together with engineering, construction and financial margins form one method and another one is based on simple scaling relations between components or structures with common technology level. In all these studies fusion competitiveness has to be improved in terms of plant availability and internal power recirculation. At present the best fission plants have a plant availability close to 95% and an internal power recirculation of the order of 3-4%. The operation and maintenance solutions of Model C and D show the right way for fusion. A remarkable rise of the fuel costs of present LWRs would first make the Generation IV breeder options and thereafter the fusion plants more competitive. The costs of safety related components, such as the containment and the equipment for severe accident mitigation (e.g. the core catcher in a LWR), should be accounted for and the extent to which the inherent fusion safety features could compensate such expenses should be analysed. For an overall assessment of the various nuclear options both internal and external costs are considered. (author)

  16. Dynamical effects in fission investigated at high excitation energy

    Directory of Open Access Journals (Sweden)

    Benlliure J.

    2016-01-01

    Full Text Available The experimental techniques used for the investigation of nuclear fission have progressed considerably during the last decade. Most of this progress is based on the use of the inverse kinematics technique allowing for the first time the complete isotopic and kinematic characterization of both fission fragments. These measurements make possible to characterize the fissioning system at saddle and at scission, and can be used to benchmark fission model calculations. One of the important ingredients in transport models describing the dynamics of the process is the dissipation parameter, governing the coupling between intrinsic and collective degrees of freedom. Recent experiments got access to the magnitude of this parameter and could also investigate its dependence in temperature and deformation.

  17. Dynamical effects in fission investigated at high excitation energy

    Science.gov (United States)

    Benlliure, J.

    2016-05-01

    The experimental techniques used for the investigation of nuclear fission have progressed considerably during the last decade. Most of this progress is based on the use of the inverse kinematics technique allowing for the first time the complete isotopic and kinematic characterization of both fission fragments. These measurements make possible to characterize the fissioning system at saddle and at scission, and can be used to benchmark fission model calculations. One of the important ingredients in transport models describing the dynamics of the process is the dissipation parameter, governing the coupling between intrinsic and collective degrees of freedom. Recent experiments got access to the magnitude of this parameter and could also investigate its dependence in temperature and deformation.

  18. Neutron emission as a function of fragment energy in the spontaneous fission of 260Md

    International Nuclear Information System (INIS)

    The authors have made the first measurement of the number of neutrons emitted in the spontaneous fission of a nuclide in which very high fragment energies dominate the fission process. In bombardments of 254Es, they produced 28-d 260Md, which was neutron-counted in a 1-m-diam spherical tank containing a Gd-doped scintillator solution. The average number of neutrons emitted per fission is only 2.58 ± 0.11, substantially less than for other actinides. A direct correlation of neutron multiplicity with fragment excitation energy is clearly demonstrated

  19. Proceedings of a specialists' meeting on neutron activation cross sections for fission and fusion energy applications

    International Nuclear Information System (INIS)

    These proceedings of a specialists' meeting on neutron activation cross sections for fission and fusion energy applications are divided into 4 sessions bearing on: - data needs: 4 conferences - experimental work: 11 conferences - theoretical work: 4 conferences - evaluation work: 5 conferences

  20. Method for measuring prompt fission neutron energy spectrum by means of threshold activation detectors

    International Nuclear Information System (INIS)

    Prompt fission neutron energy spectrum as a function of energies of neutron inducing fission has been calculated on the basis of the Madland-Nix(MN) model. The resultant spectra have been weighted to excitation functions of 27Al(n,α), 32S(n,p) and 115In(n,n) threshold reactions in order to get the average cross sections and then spectral indices which are defined as the average cross section ratio for two selective threshold reactions among the above three. It is appeared that spectral indices together with the neutron spectra are varying with energies of neutron inducing fission. This may indicate that the prompt fission neutron energy spectrum can be determined by measuring experimentally the spectral index.(Author)

  1. Dependence of Fission-Fragment Total Kinetic-Energy and Mass Distributions on the Excitation Energy and Angular-Momentum Distribution of the Fissioning Nuclide 210Po

    International Nuclear Information System (INIS)

    The fission of 210Po, produced by three different nuclear reactions (209Bi + p, 206Pb + α and 198Pt + 12C), has been studied in detail in order to establish the dependence of various scission-point properties on the excitation energy and angular-momentum distribution of the fissioning nucleus. Excitation energies of 31, 44 and 57 MeV were chosen so as to give reasonable fission cross-sections, while avoiding a large contribution from second chance fission. The experiments were conducted on a beam line of the Harwell Variable Energy Cyclotron. The mean-fragment total-kinetic-energy release was found to be dependent on the 210Po excitation energy and angular-momentum distribution. The variances of the total-kinetic energy and mass distributions were found to be a strongly dependent on excitation energy but not on angular momentum. The experimental results of this work were found to be in good agreement with the theoretical liquid-drop-model calculations of Nix and Swiatecki. (author)

  2. Total kinetic energy distribution of fission fragments in 6,7Li + 238U reactions

    International Nuclear Information System (INIS)

    The shape and width of fission-fragment (FF) mass and kinetic energy distribution provides a lot of information on the fission reaction mechanism and the structure of the compound nucleus (CN), the fragments as well as the interacting nuclei. The shape of the mass distribution of the fission fragments for the actinides induced by the proton or neutron is known to change with the incident energy. At low energies, it shows a double humped distribution which changes slowly to a single humped distribution as energy increases. However, for a reaction involving a weakly bound projectile (i.e., 6Li + 232Th), a sharp change in the shape of the mass distribution with energy was observed. The sharp increase in the peak to valley ratio (P:V) in the fission-fragment mass distribution in 6Li + 232Th reaction by Itkis et al. and in 6,7Li + 238U reactions by Santra et al. was concluded to be due to the reduced energy transfer to the composite system caused by incomplete fusion (ICF) of alpha or deuteron/triton followed by fissions. Total Kinetic Energy (TKE) distribution of fission fragments is another important observable on which the effect of projectile breakup is not explored yet. In this contribution, the study of breakup/transfer effect on average TKE distribution for 6,7Li + 238U reactions is presented

  3. Ionization chamber with fast timing properties and good energy resolution for fission fragment detection

    International Nuclear Information System (INIS)

    A twin ionization chamber for fission fragment detection is described. The chamber allows to extract both, fast timing- and energy proportional signals. A time resolution of 1.62 ns FWHM was obtained between two fission fragments detected in the two halves of the chamber. For 241Am α-particles the chamber gave an energy resolution of 1.3 percent. As counting gas methane NTP was used

  4. Microscopic description of fission in neutron-rich radium isotopes with the Gogny energy density functional

    Science.gov (United States)

    Rodrıguez-Guzmán, R.; Robledo, L. M.

    2016-01-01

    Mean-field calculations, based on the D1S, D1N and D1M parametrizations of the Gogny energy density functional, have been carried out to obtain the potential energy surfaces relevant to fission in several Ra isotopes with the neutron number 144≤ N≤ 176. Inner and outer barrier heights as well as first and second isomer excitation energies are given. The existence of a well-developed third minimum along the fission paths of Ra nuclei is analyzed in terms of the energetics of the "fragments" defining such elongated configuration. The masses and charges of the fission fragments are studied as functions of the neutron number in the parent Ra isotope. The comparison between fission and α -decay half-lives, reveals that the former becomes faster for increasing neutron numbers. Though there exists a strong variance of the results with respect to the parameters used in the computation of the spontaneous fission rate, a change in tendency is observed at N=164 with a steady increase that makes heavier neutron-rich Ra isotopes stable against fission, diminishing the importance of fission recycling in the r-process.

  5. Microscopic description of fission in neutron-rich radium isotopes with the Gogny energy density functional

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Guzman, R. [Kuwait University, Physics Department, Kuwait (Kuwait); Robledo, L.M. [Universidad Autonoma de Madrid, Departamento de Fisica Teorica, Madrid (Spain)

    2016-01-15

    Mean-field calculations, based on the D1S, D1N and D1M parametrizations of the Gogny energy density functional, have been carried out to obtain the potential energy surfaces relevant to fission in several Ra isotopes with the neutron number 144 ≤ N ≤ 176. Inner and outer barrier heights as well as first and second isomer excitation energies are given. The existence of a well-developed third minimum along the fission paths of Ra nuclei is analyzed in terms of the energetics of the ''fragments'' defining such elongated configuration. The masses and charges of the fission fragments are studied as functions of the neutron number in the parent Ra isotope. The comparison between fission and α-decay half-lives, reveals that the former becomes faster for increasing neutron numbers. Though there exists a strong variance of the results with respect to the parameters used in the computation of the spontaneous fission rate, a change in tendency is observed at N = 164 with a steady increase that makes heavier neutron-rich Ra isotopes stable against fission, diminishing the importance of fission recycling in the r-process. (orig.)

  6. Microscopic description of fission in neutron-rich radium isotopes with the Gogny energy density functional

    International Nuclear Information System (INIS)

    Mean-field calculations, based on the D1S, D1N and D1M parametrizations of the Gogny energy density functional, have been carried out to obtain the potential energy surfaces relevant to fission in several Ra isotopes with the neutron number 144 ≤ N ≤ 176. Inner and outer barrier heights as well as first and second isomer excitation energies are given. The existence of a well-developed third minimum along the fission paths of Ra nuclei is analyzed in terms of the energetics of the ''fragments'' defining such elongated configuration. The masses and charges of the fission fragments are studied as functions of the neutron number in the parent Ra isotope. The comparison between fission and α-decay half-lives, reveals that the former becomes faster for increasing neutron numbers. Though there exists a strong variance of the results with respect to the parameters used in the computation of the spontaneous fission rate, a change in tendency is observed at N = 164 with a steady increase that makes heavier neutron-rich Ra isotopes stable against fission, diminishing the importance of fission recycling in the r-process. (orig.)

  7. Optimal deuteron energy for a neutron rich nuclei source based on fission

    International Nuclear Information System (INIS)

    A neutron rich nuclei source can be conceived by using the neutron induced fission process. A high neutron flux can be obtained through the deuteron break-up reaction in the so--called converters. The number of fission events and their isotopic distributions produced in a uranium target depends on the deuteron incident beam energy, characteristics of the converter and geometry of the combination. A theoretical approach is presented in order to optimize the number of fission events in the uranium target as function of the above mentioned parameters. The initial kinetic energy of the deuteron beam, the nature of the converter and its geometry determines the angular and energy distributions of the emerging neutrons. The models used to simulate these distributions are essentially based on the Serber's approximation. The fission is treated in a microscopic-macroscopic approach using the two center shell model. A new concept is used to determine the isotopic distribution of the fission fragments as a function of the neutron energy. A steep dumping of the neutron energy is produced in the compound nucleus which modifies the two humped fission barrier and produces changes of the penetrabilities associated to each binary partition and therefore, in the isotopic distribution. Finally, our results show that a good value of the incident deuteron energy suitable for the production of neutron rich beams is closed to 80 MeV. (authors)

  8. Assessing the role of the (n, γ f) process in the low-energy fission of actinides

    Science.gov (United States)

    Talou, Patrick; Lynn, J. E.; Kawano, T.; Mosby, S.; Couture, A.; Bouland, O.

    2016-06-01

    We review the role of the (n, γ f) process in the low-energy neutron-induced fission reaction of 239Pu. Recent measurements of the average total γ-ray energy released in this reaction were performed with the Detector for Advanced Neutron Capture Experiments (DANCE) at Los Alamos. Significant fluctuations of this quantity in the resonance region below 100 eV can be interpreted by invoking the presence of the indirect (n, γ f) process. Modern calculations of the probability for such an event to occur are presented.

  9. Ohio Advanced Energy Manufacturing Center

    Energy Technology Data Exchange (ETDEWEB)

    Kimberly Gibson; Mark Norfolk

    2012-07-30

    The program goal of the Ohio Advanced Energy Manufacturing Center (OAEMC) is to support advanced energy manufacturing and to create responsive manufacturing clusters that will support the production of advanced energy and energy-efficient products to help ensure the nation's energy and environmental security. This goal cuts across a number of existing industry segments critical to the nation's future. Many of the advanced energy businesses are starting to make the transition from technology development to commercial production. Historically, this transition from laboratory prototypes through initial production for early adopters to full production for mass markets has taken several years. Developing and implementing manufacturing technology to enable production at a price point the market will accept is a key step. Since these start-up operations are configured to advance the technology readiness of the core energy technology, they have neither the expertise nor the resources to address manufacturing readiness issues they encounter as the technology advances toward market entry. Given the economic realities of today's business environment, finding ways to accelerate this transition can make the difference between success and failure for a new product or business. The advanced energy industry touches a wide range of industry segments that are not accustomed to working together in complex supply chains to serve large markets such as automotive and construction. During its first three years, the Center has catalyzed the communication between companies and industry groups that serve the wide range of advanced energy markets. The Center has also found areas of common concern, and worked to help companies address these concerns on a segment or industry basis rather than having each company work to solve common problems individually. EWI worked with three industries through public-private partnerships to sew together disparate segments helping to promote

  10. Fission-Fragment Angular, Energy, and Mass Division Correlations for the U234 (d, Pf) Reaction

    International Nuclear Information System (INIS)

    The fission of the compound nucleus U235 in the neighbourhood of its fission threshold has been studied by means of the U234 (d.pf) reaction. A three-parameter analyser was used to record simultaneously the two fission-fragment kinetic energies and the proton energy for each coincident event. The excitation energy at which fission occurs is defined by the kinetic energy of the stripped.proton. The variation of angular anisotropy with excitation energy shows considerably more structure than that obtained by Lamphere for the same nucleus resulting from fast-neutron bombardment of U234. At least eight fission channels at the saddle point have been observed for the energy region between threshold and 2 MeV above threshold. Nilsson-type calculations of single particle energies for deformed nuclei have been made for the larger deformations more nearly describing the saddle-point configuration. The single particle states identified by Lamphere are consistent with those calculated to be close to the Fermi surface for reasonable saddle-point deformations. The primary motivation for this experiment was to search for a possible correlation between mass asymmetry and angular anisotropy. Mass yields obtained from the correlated fragment energies show no variation of the anisotropy with mass ratio, in contrast with experiments where the excitation energy at which fission is occurring is not fixed and where a dependence of anisotropy on mass ratio has been observed. There is therefore no evidence from anisotropy measurements that the properties of the saddle point influence the final mass division. The average total kinetic energy release in fission varies by less than 0.5% for the different saddle-point channels observed. The variation of total kinetic energy with mass ratio has also been investigated. (author)

  11. Laser inertial fusion-based energy: Neutronic design aspects of a hybrid fusion-fission nuclear energy system

    Science.gov (United States)

    Kramer, Kevin James

    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 LFFH plants. The LFFH engine described utilizes a central fusion chamber surrounded by multiple layers of multiplying and moderating media. These layers, or blankets, include coolant plenums, a beryllium (Be) multiplier layer, a fertile fission blanket and a graphite-pebble reflector. Each layer is separated by perforated oxide dispersion strengthened (ODS) ferritic steel walls. The central fusion chamber is surrounded by an ODS ferritic steel first wall. The first wall is coated with 250-500 mum of tungsten to mitigate x-ray damage. The first wall is cooled by Li17Pb83 eutectic, chosen for its neutron multiplication and good heat transfer properties. The Li17Pb 83 flows in a jacket around the first wall to an extraction plenum. The main coolant injection plenum is immediately behind the Li17Pb83, separated from the Li17Pb83 by a solid ODS wall. This main system coolant is the molten salt flibe (2LiF-BeF2), chosen for beneficial neutronics and heat transfer properties. The use of flibe enables both fusion fuel production (tritium) and neutron moderation and multiplication for the fission blanket. A Be pebble (1 cm diameter) multiplier layer surrounds the coolant injection plenum and the coolant flows radially through perforated walls across the bed. Outside the Be layer, a fission fuel layer comprised of depleted uranium contained in Tristructural-isotropic (TRISO) fuel particles having a packing fraction of 20% in 2 cm diameter fuel pebbles. The fission blanket is cooled by

  12. Signature of fission in 16O + 159Tb system at energy ≅ 5 MeV/nucleon

    International Nuclear Information System (INIS)

    In the present work, with a view to study complete fusion-fission (CFF) and incomplete fusion-fission (ICFF) in HI induced reactions, experiment has been performed for measuring the production cross-sections for several fission products in 16O + 159Tb system at ≅ 87 MeV beam energy

  13. Evaluation of excitation energy and spin in fission fragments using the statistical model, and the FIPPS project

    Directory of Open Access Journals (Sweden)

    Sage C.

    2013-03-01

    Full Text Available We review the statistical model and its application for the process of nuclear fission. The expressions for excitation energy and spin distributions for the individual fission fragments are given. We will finally emphasize the importance of measuring prompt gamma decay to further test the statistical model in nuclear fission with the FIPPS project.

  14. Evaluation of excitation energy and spin in fission fragments using the statistical model, and the FIPPS project

    International Nuclear Information System (INIS)

    We review the statistical model and its application for the process of nuclear fission. The expressions for excitation energy and spin distributions for the individual fission fragments are given. We will finally emphasize the importance of measuring prompt gamma decay to further test the statistical model in nuclear fission with the FIPPS project. (authors)

  15. The dependence of cumulative 238U(n,f) fission yield on incident-neutron energy

    Institute of Scientific and Technical Information of China (English)

    ZHENG Na; ZHONG Chunlai; MA Liyong; CHEN Zhongjing; LI Xiangqing; LIU Tingjin; CHEN Jinxiang; FAN Tieshuan

    2009-01-01

    This work is aim at studying the dependence of fission yields on incident neutron energy,so as to produce evaluated yield sets of the energy dependence.Experimental data at different neutron energies for gas fission products 85m,87,88Kr and 138Xe resulting from the 238U(n,f) reaction are processed using codes AVERAGE for weighed average and ZOTT for simultaneous evaluation.Energy dependence of the cumulative fission product yields on the incident neutron is presented.The evaluated curve of product yield is compared with the results calculated by the TALYS-0.64 code.The present evaluation is consistent with other main libraries in error permission.The fit curve of 87,88Kr can be recommended to predict the unmeasured fission yields.Comparisons of the evaluated energy dependence curves with theoretical calculated results show that the predictions using purely theoretical model for the fission process are not sufficiently accurate and reliable for the calculations of the cumulative fission yields for the 238U(n,f).

  16. Energy dependence of mass, charge, isotopic, and energy distributions in neutron-induced fission of 235U and 239Pu

    Science.gov (United States)

    Pasca, H.; Andreev, A. V.; Adamian, G. G.; Antonenko, N. V.; Kim, Y.

    2016-05-01

    The mass, charge, isotopic, and kinetic-energy distributions of fission fragments are studied within an improved scission-point statistical model in the reactions 235U+n and 239Pu+n at different energies of the incident neutron. The charge and mass distributions of the electromagnetic- and neutron-induced fission of 214,218Ra, 230,232,238U are also shown. The available experimental data are well reproduced and the energy-dependencies of the observable characteristics of fission are predicted for future experiments.

  17. Fission fragment charge and mass distributions in 239Pu(n,f) in the adiabatic nuclear energy density functional theory

    OpenAIRE

    Regnier, D.; Dubray, N.; Schunck, N.; Verriere, M.

    2016-01-01

    Accurate knowledge of fission fragment yields is an essential ingredient of numerous applications ranging from the formation of elements in the r-process to fuel cycle optimization for nuclear energy. The need for a predictive theory applicable where no data is available is an incentive to develop a fully microscopic approach to fission dynamics. In this work, we calculate the pre-neutron emission charge and mass distributions of the fission fragments formed in the neutron-induced fission of ...

  18. Complete and incomplete fusion competition in 11B-induced fission reaction on medium mass targets at intermediate energies

    OpenAIRE

    Demekhina, N. A.; Karapetyan, G. S.; Balabekyan, A. R.

    2014-01-01

    The cross sections for the binary fission of 197Au, 181Ta and 209Bi targets induced by 11B ions were measured at intermediate energies. The fission products cross sections were studied by means of activation analysis in off-line regime observed gamma-ray spectra. The fission cross section is reconstructed on the basis of charge and mass distribution of the fission products.

  19. The optimization of the combination of various reactors and the important role of fusion-fission hybrid reactors in the development of nuclear energy in China

    International Nuclear Information System (INIS)

    For energy demand in the economic development of China in 21 Century, for seeking the strategy to develop nuclear energy in China, according to the nuclear resources in China and the perspective of international nuclear technology development, the optimization of the combination of three kinds of advanced reactors, namely, HTGR, FBR, and fusion-fission hybrid reactors in the development of nuclear energy in China was investgated. Three alternative stra tegies with different priorities were suggested

  20. Spontaneous fission

    International Nuclear Information System (INIS)

    Recent experimental results for spontaneous fission half-lives and fission fragment mass and kinetic-energy distributions and other properties of the fragments are reviewed and compared with recent theoretical models. The experimental data lend support to the existence of the predicted deformed shells near Z = 108 and N = 162. Prospects for extending detailed studies of spontaneous fission properties to elements beyond hahnium (element 105) are considered. (orig.)

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

    OpenAIRE

    Äystö J.; Penttilä H.; Gorelov D.; Rubchenya V.A.

    2012-01-01

    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-compoun...

  2. Advanced energy efficient windows

    DEFF Research Database (Denmark)

    Thomsen, Kirsten Engelund

    2007-01-01

    energy savings. In terms of energy, windows occupy a special position compared with other thermal envelope structures due to their many functions: 1) windows let daylight into the building and provide occupants with visual contact with their surroundings 2) windows protect against the outdoor climate 3......Windows should be paid special attention as they contribute a significant part of the total heat-loss coefficient of the building. Contrary to other parts of the thermal envelope the windows are not only heat loosers, but may gain heat in the day-time. Therefore there are possibilities for large......) windows transmit solar energy that may contribute to a reduction of energy consumption, but which may also lead to unpleasant overheating. In the following paragraphs the current use of windows is reviewed with an emphasis on energy, while special products like solar protection glazing and security...

  3. Advanced Performance Hydraulic Wind Energy

    Science.gov (United States)

    Jones, Jack A.; Bruce, Allan; Lam, Adrienne S.

    2013-01-01

    The Jet Propulsion Laboratory, California Institute of Technology, has developed a novel advanced hydraulic wind energy design, which has up to 23% performance improvement over conventional wind turbine and conventional hydraulic wind energy systems with 5 m/sec winds. It also has significant cost advantages with levelized costs equal to coal (after carbon tax rebate). The design is equally applicable to tidal energy systems and has passed preliminary laboratory proof-of-performance tests, as funded by the Department of Energy.

  4. Advanced energy efficient windows

    OpenAIRE

    Thomsen, Kirsten Engelund

    2007-01-01

    Windows should be paid special attention as they contribute a significant part of the total heat-loss coefficient of the building. Contrary to other parts of the thermal envelope the windows are not only heat loosers, but may gain heat in the day-time. Therefore there are possibilities for large energy savings. In terms of energy, windows occupy a special position compared with other thermal envelope structures due to their many functions: 1) windows let daylight into the building and provide...

  5. Neutrons and Kinetic Energy of Fragments in Fission of Heavy Nuclei

    International Nuclear Information System (INIS)

    The distribution of excitation energy and kinetic energy depending on the mass of the fragment formed in heavy- isotope fission by thermal neutrons is experimentally investigated. The excitation energy is shown to have a low minimum in the region of the double-magic fragment (M ∼132), to increase in the symmetrical fission area and to be at its maximum for fragments complementary to magic. The kinetic energy of the fragments measured for U235 correlates with the excitation energy. The total energy release according to the experimental data is in good agreement with calculations according to Milton's mass tables in every case except that of strongly asymmetric fission. In the measurements conducted, the ratio of the maximum of the fragment yield curve to the minimum (after neutron escape) was 500 : 1. (author)

  6. Fission-Fragment Mass Distribution and Particle Evaporation at low Energies

    OpenAIRE

    Schmitt, Ch.; Bartel, J.; Pomorski, K.; Surowiec, A.

    2002-01-01

    Fusion-fission dynamics is investigated with a special emphasis on fusion reactions at low energy for which shell effects and pairing correlations can play a crucial role leading in particular to multi-modal fission. To follow the dynamical evolution of an excited and rotating nucleus we solve a 2-dimensional Langevin equation taking explicitly light-particle evaporation into account. The confrontation theory-experiment is demonstrated to give interesting information on the model presented, i...

  7. Total fission cross sections in reactions p+181Ta investigated in inverse kinematics at relativistic energies

    International Nuclear Information System (INIS)

    Total fission cross sections of 181Ta ions colliding with hydrogen atoms at 300, 500, 800 and 1000 A MeV have been measured. The combined use of the inverse kinematics technique with an efficient detection set-up made it possible to determine these cross sections with high accuracy ranging between 8% and 17%. The new data put some light in the controversial results obtained so far and contribute to the understanding of the fission process at high excitation energies. (authors)

  8. Advanced materials for energy storage.

    Science.gov (United States)

    Liu, Chang; Li, Feng; Ma, Lai-Peng; Cheng, Hui-Ming

    2010-02-23

    Popularization of portable electronics and electric vehicles worldwide stimulates the development of energy storage devices, such as batteries and supercapacitors, toward higher power density and energy density, which significantly depends upon the advancement of new materials used in these devices. Moreover, energy storage materials play a key role in efficient, clean, and versatile use of energy, and are crucial for the exploitation of renewable energy. Therefore, energy storage materials cover a wide range of materials and have been receiving intensive attention from research and development to industrialization. In this Review, firstly a general introduction is given to several typical energy storage systems, including thermal, mechanical, electromagnetic, hydrogen, and electrochemical energy storage. Then the current status of high-performance hydrogen storage materials for on-board applications and electrochemical energy storage materials for lithium-ion batteries and supercapacitors is introduced in detail. The strategies for developing these advanced energy storage materials, including nanostructuring, nano-/microcombination, hybridization, pore-structure control, configuration design, surface modification, and composition optimization, are discussed. Finally, the future trends and prospects in the development of advanced energy storage materials are highlighted. PMID:20217798

  9. Absolute Energy Calibration of Solid-State Detectors for Fission Fragments and Heavy Ions

    International Nuclear Information System (INIS)

    Detailed measurements of the pulse-height response of silicon solid-state detectors to energetic heavy ions and fission fragments have been made. These studies have now led to a reliable method of absolute energy calibration of solid-state detectors for fission fragments, as well as to a better understanding of the somewhat peculiar response characteristics of the detectors to fission fragments and heavy ions. The use of silicon solid-state detectors in fragment kinetic energy measurements in recent years has been widespread; at the same time, questions have been raised about the detailed interpretation of such measurements because of the increasing evidence for anomalous behaviour in charge production, charge collection and charge multiplication in the case of densely ionizing particles. The present report discusses systematics and possible origins of these effects. Application of the absolute energy calibration method, which takes into account the mass and energy dependence of the response, is based simply on a Cf252 or U235 fragment pulse- height spectrum. Our studies were carried out with mono-energetic Br71, Br81 and I127 ions of energies from 30 to 120 MeV, and with fission fragments from spontaneous fission of Cf252 and neutron-induced fission of U235 and Pu239. It is shown that for a given fragment mass, over a wide energy range, the fragment energy versus pulse-height relationship is of the form E = ax + b, where E is the fragment energy and x is the measured pulse height. A dependence of pulse height on fragment mass has also been established, which leads to an energy versus pulse-height relationship, for the range of fission-fragment masses and energies, of the form E = (a + a'm)x + b + b'M, where M is the fragment mass. The effect of detector window and of detector type, resistivity and electric field have been studied. Guides to the selection of detectors and to their use with fission fragments are given. The effect of the more exact calibration

  10. Nucleon-induced fission cross-sections at transitive energy region 20-200 MeV

    International Nuclear Information System (INIS)

    The new approach to the calculation of nucleon induced fission cross sections at energies 20-200 MeV is presented. The cross sections of multiconfiguration fission is calculated as a sum of fission cross-sections for nuclei formed in process of fast (direct) and precompound stage of fission reaction. The intranuclear cascade model is used for description of direct stage and precompound-statistical model for calculation of fission and de-excitation cross sections. Calculated with new optical model parameters sets fission cross sections are compared with experimental data for neutron-induced fission of 237Np, 239Pu, 235,238U and proton-induced fission of 235,238U. Brief information about new code system is also presented. (author)

  11. Neutron-induced fission: properties of prompt neutron and γ rays as a function of incident energy

    Science.gov (United States)

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

    2016-06-01

    We have applied the Hauser-Feshbach statistical theory, in a Monte-Carlo implementation, to the de-excitation of fission fragments, obtaining a reasonable description of the characteristics of neutrons and gamma rays emitted before beta decays toward stability. Originally implemented for the spontaneous fission of 252Cf and the neutroninduced fission of 235U and 239Pu at thermal neutron energy, in this contribution we discuss the extension of the formalism to incident neutron energies up to 20 MeV. For the emission of pre-fission neutrons, at incident energies beyond second-chance fission, we take into account both the pre-equilibrium and statistical pre-fission components. Phenomenological parameterizations of mass, charge and TKE yields are used to obtain the initial conditions for the fission fragments that subsequently decay via neutron and emissions. We illustrate this approach for 239Pu(n,f).

  12. Description of Induced Nuclear Fission with Skyrme Energy Functionals: II. Finite Temperature Effects

    CERN Document Server

    Schunck, N; Carr, H

    2013-01-01

    Understanding the mechanisms of induced nuclear fission for a broad range of neutron energies could help resolve fundamental science issues, such as the formation of elements in the universe, but could have also a large impact on societal applications in energy production of nuclear waste management. The goal of this paper is to set up the foundations of a microscopic model to study the static aspects of induced fission as a function of the excitation energy of the incident neutron, from thermal to fast neutrons. To account for the high excitation energy of the compound nucleus, we employ a statistical approach based on finite temperature nuclear density functional theory with Skyrme energy densities, which we benchmark on the fission of 239Pu(n,f). We compute the evolution of the least-energy fission pathway across multidimensional potential energy surfaces with up to five collective variables as a function of the nuclear temperature, and predict the evolution of both the inner and outer fission barriers as ...

  13. DIRECT ENERGY CONVERSION (DEC) FISSION REACTORS - A U.S. NERI PROJECT

    Energy Technology Data Exchange (ETDEWEB)

    D. BELLER; G. POLANSKY; ET AL

    2000-11-01

    The direct conversion of the electrical energy of charged fission fragments was examined early in the nuclear reactor era, and the first theoretical treatment appeared in the literature in 1957. Most of the experiments conducted during the next ten years to investigate fission fragment direct energy conversion (DEC) were for understanding the nature and control of the charged particles. These experiments verified fundamental physics and identified a number of specific problem areas, but also demonstrated a number of technical challenges that limited DEC performance. Because DEC was insufficient for practical applications, by the late 1960s most R&D ceased in the US. Sporadic interest in the concept appears in the literature until this day, but there have been no recent programs to develop the technology. This has changed with the Nuclear Energy Research Initiative that was funded by the U.S. Congress in 1999. Most of the previous concepts were based on a fission electric cell known as a triode, where a central cathode is coated with a thin layer of nuclear fuel. A fission fragment that leaves the cathode with high kinetic energy and a large positive charge is decelerated as it approaches the anode by a charge differential of several million volts, it then deposits its charge in the anode after its kinetic energy is exhausted. Large numbers of low energy electrons leave the cathode with each fission fragment; they are suppressed by negatively biased on grid wires or by magnetic fields. Other concepts include magnetic collimators and quasi-direct magnetohydrodynamic generation (steady flow or pulsed). We present the basic principles of DEC fission reactors, review the previous research, discuss problem areas in detail and identify technological developments of the last 30 years relevant to overcoming these obstacles. A prognosis for future development of direct energy conversion fission reactors will be presented.

  14. Study of advanced fission power reactor development for the United States. Volume II

    International Nuclear Information System (INIS)

    This report presents the results of a multi-phase research study which had as its objective the comparative study of various advanced fission reactors and evaluation of alternate strategies for their development in the USA through the year 2020. By direction from NSF, ''advanced'' reactors were defined as those which met the dual requirements of (1) offering a significant improvement in fissile fuel utilization as compared to light-water reactors and (2) currently receiving U.S. Government funding. (A detailed study of the LMFBR was specifically excluded, but cursory baseline data were obtained from ERDA sources.) Included initially were the High-Temperature Gas-Cooled Reactor (HTGR), Gas-Cooled Fast Reactor (GCFR), Molten Salt Reactor (MSR), and Light-Water Breeder Reactor (LWBR). Subsequently, the CANDU Heavy Water Reactor (HWR) was included for comparison due to increased interest in its potential. This volume presents the reasoning process and analytical methods utilized to arrive at the conclusions for the overall study

  15. The contrasting fission potential-energy structure of actinides and mercury isotopes

    CERN Document Server

    Ichikawa, Takatoshi; Möller, Peter; Sierk, Arnold J

    2012-01-01

    Fission-fragment mass distributions are asymmetric in fission of typical actinide nuclei for nucleon number $A$ in the range $228 \\lnsim A \\lnsim 258$ and proton number $Z$ in the range $90\\lnsim Z \\lnsim 100$. For somewhat lighter systems it has been observed that fission mass distributions are usually symmetric. However, a recent experiment showed that fission of $^{180}$Hg following electron capture on $^{180}$Tl is asymmetric. An earlier experiment has shown fission of $^{198}$Hg and nearby nuclei is symmetric, but with hints of asymmetric yield distributions up to about 10 MeV above the saddle-point energy. We calculate potential-energy surfaces for a typical actinide nucleus and for 12 even isotopes in the range $^{178}$Hg--$^{200}$Hg, demonstrating the radical differences between actinide and mercury potential surfaces. We discuss these differences and how the changing potential-energy structure along the mercury isotope chain affects the observed (a)symmetry of the fission fragments. We show that the ...

  16. Advanced energy conversion and application

    International Nuclear Information System (INIS)

    This VDI-report 1029 contains the manuscripts of 45 lectures which have been held on the expert meeting ''Advanced energy conversion and application''. The following 3 main subjects have been dealt with: I electric power stations and heating and power stations, II industrial energy technology, III energy supply of buildings. For each of the 45 manuscripts, a separated assessment with regard to the content has been elaborated. (HW)

  17. Recent Advances in Power Conversion and Heat Rejection Technology for Fission Surface Power

    Science.gov (United States)

    Mason, Lee

    2010-01-01

    Under the Exploration Technology Development Program, the National Aeronautics and Space Administration (NASA) and the Department of Energy (DOE) are jointly developing Fission Surface Power (FSP) technology for possible use in human missions to the Moon and Mars. A preliminary reference concept was generated to guide FSP technology development. The concept consists of a liquid-metal-cooled reactor, Stirling power conversion, and water heat rejection, with Brayton power conversion as a backup option. The FSP project has begun risk reduction activities on some key components with the eventual goal of conducting an end-to-end, non-nuclear, integrated system test. Several power conversion and heat rejection hardware prototypes have been built and tested. These include multi-kilowatt Stirling and Brayton power conversion units, titanium-water heat pipes, and composite radiator panels.

  18. Measurements of prompt neutron multiplicity distributions in correlation with mass-energy distribution of fission fragments in spontaneous fission of 252Cf, 244Cm and 248Cm

    International Nuclear Information System (INIS)

    The number of prompt neutrons emitted in the fission event have been measured separately for each complementary fragment in coincidence with fragment mass and kinetic energies in spontaneous fission of 252Cf, 244Cm and 248Cm. Two high efficient Gd-loaded liquid scintillator tanks were used for the neutron registration. Approximately 3x106 fission events coincident with prompt neutron emission have been accumulated for each isotope. The mean neutron multiplicity, the dispersion and the covariance of the multiplicity distributions have been obtained as a function of fission fragment mass and kinetic energy. The neutron multiplicity data have been corrected for neutron registration efficiency, background and pile-up. Dependencies of the moments of the multiplicity distributions on the fragment mass and total kinetic energy for different mass bins, as well as mass and total kinetic energy distributions of the fission fragments are presented, discussed and compared for the different isotopes investigated. The results showed a different behavior of the moments of the multiplicity distribution depending on the fragment mass asymmetry that reflects changes in the dynamical effects for different fission modes. (author)

  19. AMP-activated protein kinase mediates mitochondrial fission in response to energy stress

    Science.gov (United States)

    Courchet, Julien; Lewis, Tommy L.; Losón, Oliver C.; Hellberg, Kristina; Young, Nathan P.; Chen, Hsiuchen; Polleux, Franck; Chan, David C.; Shaw, Reuben J.

    2016-01-01

    Mitochondria undergo fragmentation in response to electron transport chain (ETC) poisons and mitochondrial DNA–linked disease mutations, yet how these stimuli mechanistically connect to the mitochondrial fission and fusion machinery is poorly understood. We found that the energy-sensing adenosine monophosphate (AMP)–activated protein kinase (AMPK) is genetically required for cells to undergo rapid mitochondrial fragmentation after treatment with ETC inhibitors. Moreover, direct pharmacological activation of AMPK was sufficient to rapidly promote mitochondrial fragmentation even in the absence of mitochondrial stress. A screen for substrates of AMPK identified mitochondrial fission factor (MFF), a mitochondrial outer-membrane receptor for DRP1, the cytoplasmic guanosine triphosphatase that catalyzes mitochondrial fission. Nonphosphorylatable and phosphomimetic alleles of the AMPK sites in MFF revealed that it is a key effector of AMPK-mediated mitochondrial fission. PMID:26816379

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

    International Nuclear Information System (INIS)

    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 243Cm. 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 243Cm 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

  1. Benchmarking a fission-product release computer program containing a Gibbs energy minimizer

    International Nuclear Information System (INIS)

    The computer program SOURCE IST 2.0 contains a 1997 model of fission-product vaporization, developed by B.J. Corse et al. That model was tractable on computers of that day. However, the understanding of fuel thermochemistry has advanced since that time. A new prototype computer program was developed with: a) newer Royal Military College of Canada thermodynamic model of uranium dioxide fuel, b) new model for fission-product vaporization from the fuel surface, c) a user-callable thermodynamics subroutine library, d) an updated nuclear data library, and e) an updated nuclide generation and depletion algorithm. The prototype has been benchmarked against experimental results. (author)

  2. Studies on fission with ALADIN. Precise and simultaneous measurement of fission yields, total kinetic energy and total prompt neutron multiplicity at GSI

    Science.gov (United States)

    Martin, Julie-Fiona; Taieb, Julien; Chatillon, Audrey; Bélier, Gilbert; Boutoux, Guillaume; Ebran, Adeline; Gorbinet, Thomas; Grente, Lucie; Laurent, Benoit; Pellereau, Eric; Alvarez-Pol, Héctor; Audouin, Laurent; Aumann, Thomas; Ayyad, Yassid; Benlliure, Jose; Casarejos, Enrique; Cortina Gil, Dolores; Caamaño, Manuel; Farget, Fanny; Fernández Domínguez, Beatriz; Heinz, Andreas; Jurado, Beatriz; Kelić-Heil, Aleksandra; Kurz, Nikolaus; Nociforo, Chiara; Paradela, Carlos; Pietri, Stéphane; Ramos, Diego; Rodríguez-Sànchez, Jose-Luis; Rodríguez-Tajes, Carme; Rossi, Dominic; Schmidt, Karl-Heinz; Simon, Haik; Tassan-Got, Laurent; Vargas, Jossitt; Voss, Bernd; Weick, Helmut

    2015-12-01

    A novel technique for fission studies, based on the inverse kinematics approach, is presented. Following pioneering work in the nineties, the SOFIA Collaboration has designed and built an experimental set-up dedicated to the simultaneous measurement of isotopic yields, total kinetic energies and total prompt neutron multiplicities, by fully identifying both fission fragments in coincidence, for the very first time. This experiment, performed at GSI, permits to study the fission of a wide variety of fissioning systems, ranging from mercury to neptunium, possibly far from the valley of stability. A first experiment, performed in 2012, has provided a large array of unprecedented data regarding the nuclear fission process. An excerpt of the results is presented. With this solid starter, further improvements of the experimental set-up are considered, which are consistent with the expected developments at the GSI facility, in order to measure more fission observables in coincidence. The completeness reached in the SOFIA data, permits to scrutinize the correlations between the interesting features of fission, offering a very detailed insight in this still unraveled mechanism.

  3. Studies on fission with ALADIN. Precise and simultaneous measurement of fission yields, total kinetic energy and total prompt neutron multiplicity at GSI

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Julie-Fiona; Taieb, Julien; Chatillon, Audrey; Belier, Gilbert; Boutoux, Guillaume; Ebran, Adeline; Gorbinet, Thomas; Grente, Lucie; Laurent, Benoit; Pellereau, Eric [CEA DAM Bruyeres-le-Chatel, Arpajon (France); Alvarez-Pol, Hector; Ayyad, Yassid; Benlliure, Jose; Cortina Gil, Dolores; Caamano, Manuel; Fernandez Dominguez, Beatriz; Paradela, Carlos; Ramos, Diego; Rodriguez-Sanchez, Jose-Luis; Vargas, Jossitt [Universidad de Santiago de Compostela, Santiago de Compostela (Spain); Audouin, Laurent; Tassan-Got, Laurent [CNRS/IN2P3, IPNO, Orsay (France); Aumann, Thomas [Technische Universitaet Darmstadt, Darmstadt (Germany); Casarejos, Enrique [Universidad de Vigo, Vigo (Spain); Farget, Fanny; Rodriguez-Tajes, Carme [CNRS/IN2P3, GANIL, Caen (France); Heinz, Andreas [Chalmers University of Technology, Gothenburg (Sweden); Jurado, Beatriz [CNRS/IN2P3, CENBG, Gradignan (France); Kelic-Heil, Aleksandra; Kurz, Nikolaus; Nociforo, Chiara; Pietri, Stephane; Rossi, Dominic; Schmidt, Karl-Heinz; Simon, Haik; Voss, Bernd; Weick, Helmut [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany)

    2015-12-15

    A novel technique for fission studies, based on the inverse kinematics approach, is presented. Following pioneering work in the nineties, the SOFIA Collaboration has designed and built an experimental set-up dedicated to the simultaneous measurement of isotopic yields, total kinetic energies and total prompt neutron multiplicities, by fully identifying both fission fragments in coincidence, for the very first time. This experiment, performed at GSI, permits to study the fission of a wide variety of fissioning systems, ranging from mercury to neptunium, possibly far from the valley of stability. A first experiment, performed in 2012, has provided a large array of unprecedented data regarding the nuclear fission process. An excerpt of the results is presented. With this solid starter, further improvements of the experimental set-up are considered, which are consistent with the expected developments at the GSI facility, in order to measure more fission observables in coincidence. The completeness reached in the SOFIA data, permits to scrutinize the correlations between the interesting features of fission, offering a very detailed insight in this still unraveled mechanism. (orig.)

  4. Studies on fission with ALADIN. Precise and simultaneous measurement of fission yields, total kinetic energy and total prompt neutron multiplicity at GSI

    International Nuclear Information System (INIS)

    A novel technique for fission studies, based on the inverse kinematics approach, is presented. Following pioneering work in the nineties, the SOFIA Collaboration has designed and built an experimental set-up dedicated to the simultaneous measurement of isotopic yields, total kinetic energies and total prompt neutron multiplicities, by fully identifying both fission fragments in coincidence, for the very first time. This experiment, performed at GSI, permits to study the fission of a wide variety of fissioning systems, ranging from mercury to neptunium, possibly far from the valley of stability. A first experiment, performed in 2012, has provided a large array of unprecedented data regarding the nuclear fission process. An excerpt of the results is presented. With this solid starter, further improvements of the experimental set-up are considered, which are consistent with the expected developments at the GSI facility, in order to measure more fission observables in coincidence. The completeness reached in the SOFIA data, permits to scrutinize the correlations between the interesting features of fission, offering a very detailed insight in this still unraveled mechanism. (orig.)

  5. Partition between the fission fragments of the excitation energy and of the neutron multiplicity at scission in low-energy fission

    Science.gov (United States)

    Carjan, N.; Hambsch, F.-J.; Rizea, M.; Serot, O.

    2012-04-01

    The partition between the light (L) and the heavy (H) fission fragments of the excitation energy available at scission is studied in the framework of the sudden approximation, i.e., under the assumption that the neck rupture and the absorption of the neck pieces by the fragments happen infinitely fast. We are dealing with a sudden transition between two different nuclear configurations (αi→αf) and we only need to know the two sets of neutron eigenstates involved. The accent in the present work is put on the dependence of this share of energy on the mass asymmetry AL/AH of the primary fission fragments during the low-energy fission of 236U. In particular, for every fragment mass A we estimate the scission neutron multiplicity νsc, the average energy cost for their release , the primary fragments' excitation energy Esc*, and the corresponding temperature Tsc. The results are analyzed separately for each value of Ω (the projection of the angular momentum on the symmetry axis). As general trends, a decrease of Esc* (Tsc) and an increase of νsc () with increasing A were observed.

  6. Final report on study of advanced fission power reactor development for the United States. Volume III

    International Nuclear Information System (INIS)

    This three-volume set details a multistage research study on the comparison of various advanced fission reactors and evaluation of alternate strategies for their development in the USA through the year 2020. Volume III presents the basic data and other input information utilized in the process of the study. Detailed reactor and fuel-cycle information is contained on the HTGR, GCFR, MSBR, LWBR, and CANDU-HWR, as obtained by BCL staff from numerous sources. These data have been assembled, critically reviewed, and modified where necessary to assure consistency, both internally for each reactor system, and between reactor types. Similar, comparative information was required for the LWR mass balances, fuel cycle, etc., but this was generally accepted from ERDA sources without the critical evaluation to which the other data were subjected. Other detailed information that relates to the objective of the study, e.g., projections of nuclear power growth and uranium availability, generic safeguards information, description of computerized models, etc., is incorporated for ready reference

  7. Method of measurement of cross sections of heavy nuclei fission induced by intermediate energy protons

    International Nuclear Information System (INIS)

    The purpose of this work is experimental studies of the energy dependence of the fission cross sections of heavy nuclei, natPb, 209Bi, 232Th, 233U, 235U, 238U, 237Np and 239Pu, by protons at the energies from 200 to 1000 MeV. At present experiment the method based on use of the gas parallel plate avalanche counters (PPACs) for registration of complementary fission fragments in coincidence and the telescope of scintillation counters for direct counting of the incident protons on the target has been used. First preliminary results of the energy dependences of proton induced fission cross sections for natPb, 209Bi, 235U and 238U are reported. (author)

  8. Probing energy dissipation, γ-ray and neutron multiplicity in the thermal neutron-induced fission of 239Pu

    Science.gov (United States)

    Pahlavani, M. R.; Mirfathi, S. M.

    2016-04-01

    The incorporation of the four-dimensional Langevin equations led to an integrative description of fission cross-section, fragment mass distribution and the multiplicity and energy distribution of prompt neutrons and γ-rays in the thermal neutron-induced fission of 239Pu. The dynamical approach presented in this paper thoroughly reproduces several experimental observables of the fission process at low excitation energy.

  9. Nucleon-induced fission cross sections of heavy nuclei in the intermediate energy region

    International Nuclear Information System (INIS)

    Fission is the most important nuclear reaction for society at large today due to its use in energy production. However, this has raised the problem of how to treat the long-lived radioactive waste from nuclear reactors. A radical solution would be to change the composition of the waste into stable or short-lived nuclides, which could be done through nuclear transmutation. Such a concept requires accelerator-driven systems to be designed, where those for transmutation are reactor hybrids. This thesis is a contribution to the knowledge base for developing transmutation systems, specifically with respect to the computational modeling of the underlying nuclear reactions, induced by the incident and secondary particles. Intermediate energy fission cross sections are one important type of such data. Moreover, they are essential for understanding the fission process itself and related nuclear interactions. The experimental part of this work was performed at the neutron beam facility of the The Svedberg Laboratory in Uppsala. Fission cross sections of 238U, 209Bi, Pb, 208Pb, 197Au, W, and 181Ta were measured for neutrons in the range En, = 30-160 MeV using thin-film breakdown counters for the fission fragment detection. A model was developed for the determination of the efficiency of such detectors. A compilation of existing data on proton-induced fission cross sections for nuclei from 165Ho to 239Pu was performed. The results, which constitute the main body of information in this field, were added to the worldwide EXFOR database. The dependences of the cross sections on incident energy and target nucleus were studied, which resulted in systematics that make it possible to give estimates for unmeasured nuclides. Nucleon-induced fission cross sections were calculated using an extended version of the cascade exciton model. A comparison with the systematics and the experimental data obtained in the present work revealed significant discrepancies. A modification of the model

  10. Advances in Development of the Fission Product Extraction Process for the Separation of Cesium and Strontium from Spent Nuclear Fuel

    Energy Technology Data Exchange (ETDEWEB)

    JAck D. Law

    2007-09-01

    The Fission Product Extraction (FPEX) Process is being developed as part of the United States Department of Energy Advanced Fuel Cycle Initiative for the simultaneous separation of cesium (Cs) and strontium (Sr) from spent light water reactor (LWR) fuel. Separation of the Cs and Sr will reduce the short-term heat load in a geological repository, and when combined with the separation of americium (Am) and curium (Cm), could increase the capacity of the geological repository by a factor of approximately 100. The FPEX process is based on two highly specific extractants: 4,4',(5')-Di-(t-butyldicyclo-hexano)-18-crown-6 (DtBuCH18C6) and Calix[4]arene-bis-(tert-octylbenzo-crown-6) (BOBCalixC6). The DtBuCH18C6 extractant is selective for strontium and the BOBCalixC6 extractant is selective for cesium. Results of flowsheet testing of the FPEX process with a simulated feed solution in 3.3-cm centrifugal contactors are detailed. Removal efficiencies, distribution coefficient data, coextraction of metals, and process hydrodynamic performance are discussed along with recommendations for future flowsheet testing with actual spent nuclear fuel.

  11. Microscopic description of fission in neutron-rich Radium isotopes with the Gogny energy density functional

    CERN Document Server

    Rodriguez-Guzman, R R

    2015-01-01

    Mean field calculations, based on the D1S, D1N and D1M parametrizations of the Gogny energy density functional, have been carried out to obtain the potential energy surfaces relevant to fission in several Ra isotopes with the neutron number 144 $\\le$ N $\\le$ 176. Inner and outer barrier heights as well as first and second isomer excitation energies are given. The existence of a well developed third minimum along the fission paths of Ra nuclei, is analyzed in terms of the energetics of the "fragments" defining such elongated configuration. The masses and charges of the fission fragments are studied as functions of the neutron number in the parent Ra isotope. The comparison between fission and $\\alpha$-decay half-lives, reveals that the former becomes faster for increasing neutron numbers. Though there exists a strong variance of the results with respect to the parameters used in the computation of the spontaneous fission rate, a change in tendency is observed at N=164 with a steady increase that makes heavier ...

  12. Fission fragment charge and mass distributions in 239Pu(n,f) in the adiabatic nuclear energy density functional theory

    CERN Document Server

    Regnier, D; Schunck, N; Verriere, M

    2016-01-01

    Accurate knowledge of fission fragment yields is an essential ingredient of numerous applications ranging from the formation of elements in the r-process to fuel cycle optimization for nuclear energy. The need for a predictive theory applicable where no data is available is an incentive to develop a fully microscopic approach to fission dynamics. In this work, we calculate the pre-neutron emission charge and mass distributions of the fission fragments formed in the neutron-induced fission of 239Pu using a microscopic method based on nuclear energy density functional (EDF) method, where large amplitude collective motion is treated adiabatically using the time dependent generator coordinate method (TDGCM) under the Gaussian overlap approximation (GOA). Fission fragment distributions are extracted from the flux of the collective wave packet through the scission line. We find that the main characteristics of the fission charge and mass distributions can be well reproduced by existing energy functionals even in tw...

  13. Simulation of neutron rich nuclei production through 239U fission at intermediates energies

    International Nuclear Information System (INIS)

    The theoretical part and some results obtained from a model realised for fission processes in wide range of mass-asymmetries are presented. The fission barriers are computed in a tridimensional configuration space using the Yukawa - plus - exponential macroscopic energies corrected within the Strutinsky procedure. It is assumed that channel probabilities are proportional with Gamow penetrabilities. The model is applied for the disintegration of the 239U in order to determine the relative yields for the production of neutron rich nuclei at diverse intermediate energies. (author)

  14. Decay heat and anti-neutrino energy spectra in fission fragments from total absorption spectroscopy

    Science.gov (United States)

    Rykaczewski, Krzysztof

    2015-10-01

    Decay studies of over forty 238U fission products have been studied using ORNL's Modular Total Absorption Spectrometer. The results are showing increased decay heat values, by 10% to 50%, and the energy spectra of anti-neutrinos shifted towards lower energies. The latter effect is resulting in a reduced number of anti-neutrinos interacting with matter, often by tens of percent per fission product. The results for several studied nuclei will be presented and their impact on decay heat pattern in power reactors and reactor anti-neutrino physics will be discussed.

  15. Fission-fragment kinetic-energy distributions from a two-dimensional Fokker-Planck equation

    International Nuclear Information System (INIS)

    We calculate the fission-fragment kinetic-energy distribution for the compound nucleus 213At by simultaneously taking into account spreading in a stretching degree of freedom and fluctuations in a fission degree of freedom. This is done in terms of an approximate solution of a two-dimensional Fokker-Planck equation obtained by propagating Gaussian bundles in momentum space. When compared as functions of nuclear temperature with experimental data, our calculated mean kinetic energies are in approximate agreement and our calculated variances are slightly too small

  16. Odd–even effect in fragment angular momentum in low-energy fission of actinides

    Indian Academy of Sciences (India)

    B S Tomar; R Tripathi; A Goswami

    2007-01-01

    Quantitative explanation for the odd–even effect on fragment angular momenta in the low-energy fission of actinides have been provided by taking into account the single particle spin of the odd proton at the fragment's scission point deformation in the case of odd- fragments along with the contribution from the population of angular momentum bearing collective vibrations of the fissioning nucleus at scission point. The calculated fragment angular momenta have been found to be in very good agreement with the experimental data for fragments in the mass number region of 130–140. The odd–even effect observed in the fragment angular momenta in the low-energy fission of actinides has been explained quantitatively for the first time.

  17. Implementation of a Gibbs energy minimizer in a fission-product release computer program

    International Nuclear Information System (INIS)

    SOURCE 2.0 is the Canadian computer program for calculating fractional release of fission products from the UO2 fuel matrix. In nuclear accidents, fission-product release from fuel is one of the physical steps required before radiation dose from fission products can affect the public. Fission-product release calculations are a step in the analysis path to calculating dose consequences to the public from postulated nuclear accidents. SOURCE 2.0 contains a 1997 model of fission-product vaporization by B.J. Corse et al. based on lookup tables generated with the FACT computer program. That model was tractable on computers of that day. However, the understanding of fuel thermochemistry has advanced since that time. Additionally, computational resources have significantly improved since the time of the development of the Corse model and now allow incorporation of the more-rigorous thermodynamic treatment. Combining the newer Royal Military College of Canada (RMC) thermodynamic model of irradiated uranium dioxide fuel, a new model for fission-product vaporization from the fuel surface, a commercial user-callable thermodynamics subroutine library (ChemApp), an updated nuclide list, and updated nuclear physics data, a prototype computer program based on SOURCE IST 2.0P11 has been created that performs thermodynamic calculations internally. The resulting prototype code (with updated and revised data) provides estimates of 140La releases that are in better agreement with experiments than the original code version and data. The improvement can be quantified by a reduction in the mean difference between experimental and calculated release fractions from 0.70 to 0.07. 140La is taken to be representative of “low-volatile” fission products. To ensure that the existing acceptable performance for noble gases and volatile fission products is not adversely affected by the changes, comparisons were also made for a representative noble gas, 85Kr, and a representative volatile

  18. 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.

  19. 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. PMID:27081973

  20. XEUS: Exploratory Energy Utilization Systemic s for Fission Fusion Hybrid Application

    International Nuclear Information System (INIS)

    World energy outlook requires environmental friendliness, sustain ability and improved economic feasibility. The Exploratory Energy Utilization Systemic s (XEUS) is being developed at the Seoul National University (SNU) to satisfy these demands. Generation IV (Gen IV) and fusion reactors are considered as candidates for the primary system. Battery Omnibus Reactor Integral System (BORIS) is a liquid-metal cooled fast reactor which is one of the Gen IV concepts. Fusion Engineering Lifetime Integral Explorer (FELIX) is a fusion demonstration reactor for power generation. These two concepts are considered as dominant options for future nuclear energy source from the environmental, commercial and nonproliferation points of view. XEUS may as well be applied to the fusion-fission hybrid system. The system code is being developed to analyze the steady state and transient behavior of the primary system. Compact and high efficiency heat exchangers are designed in the Loop Energy Exchanger Integral System (LEXIS). Modular Optimized Brayton Integral System (MOBIS) incorporates a Brayton cycle with supercritical fluid to achieve high power conversion ratio. The high volumetric energy density of the Brayton cycle enables designers to reduce the size and eventually the cost of the system when compared with that of the Rankine cycle. MOBIS is home to heat exchangers and turbo machineries. The advanced shell-and-tube or printed circuit heat exchanger is considered as heat transfer components to reduce size of the system. The supercritical fluid driven turbines and compressor are designed to achieve higher component efficiency. Thermo hydrodynamic characteristics of each component in MOBIS are demonstrated utilizing computational fluid dynamics software CFXR. Another key contributor to the reduction of capital costs per unit energy has to do with manufacturing and assembly processes that streamline plant construction by minimizing construction work and time. In a three

  1. Energy Storage (II): Developing Advanced Technologies

    Science.gov (United States)

    Robinson, Arthur L

    1974-01-01

    Energy storage, considered by some scientists to be the best technological and economic advancement after advanced nuclear power, still rates only modest funding for research concerning the development of advanced technologies. (PEB)

  2. Theory and applications of the fission matrix method for continuous-energy Monte Carlo

    International Nuclear Information System (INIS)

    Highlights: • The fission matrix method is implemented into the MCNP Monte Carlo code. • Eigenfunctions and eigenvalues of power distributions are shown and studied. • Source convergence acceleration is demonstrated for a fuel storage vault problem. • Forward flux eigenmodes and relative uncertainties are shown for a reactor problem. • Eigenmodes expansions are performed during source convergence for a reactor problem. - Abstract: The fission matrix method can be used to provide estimates of the fundamental mode fission distribution, the dominance ratio, the eigenvalue spectrum, and higher mode forward and adjoint eigenfunctions of the fission distribution. It can also be used to accelerate the convergence of power method iterations and to provide basis functions for higher-order perturbation theory. The higher-mode fission sources can be used to determine higher-mode forward fluxes and tallies, and work is underway to provide higher-mode adjoint-weighted fluxes and tallies. These aspects of the method are here both theoretically justified and demonstrated, and then used to investigate fundamental properties of the transport equation for a continuous-energy physics treatment. Implementation into the MCNP6 Monte Carlo code is also discussed, including a sparse representation of the fission matrix, which permits much larger and more accurate representations. Properties of the calculated eigenvalue spectrum of a 2D PWR problem are discussed: for a fine enough mesh and a sufficient degree of sampling, the spectrum both converges and has a negligible imaginary component. Calculation of the fundamental mode of the fission matrix for a fuel storage vault problem shows how convergence can be accelerated by over a factor of ten given a flat initial distribution. Forward fluxes and the relative uncertainties for a 2D PWR are shown, both of which qualitatively agree with expectation. Lastly, eigenmode expansions are performed during source convergence of the 2D PWR

  3. Brownian shape motion on five-dimensional potential-energy surfaces: Nuclear fission-fragment mass distributions

    OpenAIRE

    Randrup, Jorgen; Moller, Peter

    2011-01-01

    Although nuclear fission can be understood qualitatively as an evolution of the nuclear shape, a quantitative description has proven to be very elusive. In particular, until now, there exists no model with demonstrated predictive power for the fission fragment mass yields. Exploiting the expected strongly damped character of nuclear dynamics, we treat the nuclear shape evolution in analogy with Brownian motion and perform random walks on five-dimensional fission potential-energy surfaces whic...

  4. Further evidence for energy sorting from the even-odd effect in fission-fragment element distributions

    OpenAIRE

    Schmidt, Karl-Heinz; Jurado, Beatriz

    2010-01-01

    The even-odd effect in fission is explained by a model based on statistical mechanics. It reveals that the variation of the even-odd effect with the mass of the fissioning nucleus and the increase towards asymmetric splits is due to the important statistical weight of configurations where the light fission fragment populates the ground state of an even-even nucleus. This implies that entropy drives excitation energy and unpaired nucleons predominantly to the heavy fragment. Therefore, the eve...

  5. Excitation Functions of Fusion and Fission for 32S+170Er at Energies Near and Below Coulomb Barrier

    Institute of Scientific and Technical Information of China (English)

    BAO; Peng-fei; LIN; Cheng-jian; YANG; Feng; JIA; Hui-ming; XU; Xin-xing; YANG; Lei; SUN; Li-jie; MA; Nan-ru; ZHANG; Huan-qiao; LIU; Zu-hua

    2013-01-01

    Excitation functions of fusion evaporation residue(ER)and fission for 32S+170Er system at near barrier energy region were measured,respectively.With the comparison to the calculations of coupledchannels effects,it is accessible to investigate the impacts on the fusion and fission processes of target deformation and the dependence on the entrance-channel.The experiment was performed at Beijing HI-13 Tandem Accelerator.Fission and fusion evaporation

  6. Yield-Energy Evaluation of 85Kr of 239Pu+n Fission

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>The yields of 85Kr, the important production of the 239Pu fission, were re-evaluated over the incident neutron energy 1-15 MeV, based upon all the experimental data. The yields as function of energ

  7. Medium and long-term scenarios for fission nuclear energy and role of innovative concepts

    International Nuclear Information System (INIS)

    The course addresses medium and long-term scenarios for nuclear energy and role of innovative concepts. In particular, presented are several major issues related to plutonium management, transmutation of minor actinides and long-lived fission products, and accelerator driven systems. The paper essentially reproduces transparencies prepared as lecture notes. (author)

  8. Medium and long term scenarios for fission nuclear energy and role of innovative concepts

    International Nuclear Information System (INIS)

    In the assessment of medium and long-term scenarios for fission nuclear energy and the role of innovative concepts, the options for the back-end of the fuel cycle play a central role. Three classical scenarios are analysed corresponding to open cycle, reprocessing for Pu utilisation and some long-lived fission products transmutation. We will first examine the impact of the fuel cycle in terms of waste toxicity. Subsequently, we will quickly remind the issues associated to Pu utilisation. Finally, we will extensively describe the transmutation: physics, applications and scenarios

  9. 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.

  10. Investigating the fission process at high excitation energies through proton induced reactions on 181Ta

    Directory of Open Access Journals (Sweden)

    Paradela C.

    2010-10-01

    Full Text Available In this work we have investigated total fission cross section of 181Ta+1H at FRS (FRagment Separator -GSI at 1, 0.8, 0.5 and 0.3 GeV with an specific setup, providing high accuracy measurements of the cross section values. We compare the results obtained in this experiment, with several calculations performed with the intra-nuclear cascade model (INCL v4.1 coupled to de-excitation code (ABLAv3p, according to two different models describing fission process at high-excitation energies: statistical model of Bohr and Wheeler and the dynamical description of the fission process. The comparison with data of previous experiments is also discussed in order to address the existing discrepancies with this new results.

  11. High energy {gamma} emission in the spontaneous fission of {sup 252}Cf; Emission {gamma} de grande energie dans la fission spontanee de {sup 252}Cf

    Energy Technology Data Exchange (ETDEWEB)

    Badimon, C.; Barreau, G.; Doan, T.P.; Pedemay, G. [Centre d`Etudes Nucleaires, Bordeaux-1 Univ., 33 Gradignan (France); Gautherin, C.; Houry, M.; Korten, W.; Le Coz, Y.; Lucas, R.; Thiesen, Ch. [Dept. d`Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l`Instrumentation Associee, CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France); Belier, G.; Meot, M.V. [CEA Centre d`Etudes de Bruyeres-le-Chatel, 91 (France); Astier, A.; Ducroux, L.; Meyer, M.; Redon, N. [Inst.de Physique Nucleaire, Lyon-1 Univ., 69 - Villeurbanne (France)

    1997-06-01

    The prompt {gamma} emission in the spontaneous fission of {sup 252}Cf is characterized by an energy spectrum which extends up to 20 MeV. It was established that the spectrum presents in the neighbourhood of symmetric fission an intensity bump in the 3-8 MeV {gamma} energy interval. The origin of this phenomenon is still not well understood, so that it was found interesting to carry out new measurements. The spectrum of the {gamma} rays emitted in spontaneous fission of {sup 252}Cf has been measurement in the EUROGAM II multidetector using photovoltaic cells to detect fragments. The aim of the experiment was to investigate the {gamma} yield enhancement which appears for mass fragment ratio near 132/120. This enhancement was found to be composed of two peaks located at 4 MeV and 5.5 MeV respectively. The results obtained confirm the intensity bound in the 3-8 MeV region but this augmentation reaches the maximum when the heavy fragment is near the mass 132. Beyond mass 140 the phenomenon diminish and the {gamma} spectrum regains the behaviour expected for a statistic emission. The additional structure at 5.5 MeV does not vary with excitation energy while the excitation function of the 4 MeV structure is more structured and presents a maximum when the excitation energy is near 8 MeV. It is likely that all or part of this observed phenomenon is due to a particular excitation mode of this isotope associated for instance with a low energy dipole resonance. A theoretical study of this collective effect is under way 3 refs.

  12. Overview of research by the fission group in Trombay

    Indian Academy of Sciences (India)

    R K Chourdhury

    2015-08-01

    Nuclear fission studies in Trombay began nearly six decades ago, with the commissioning of the APSARA research reactor. Early experimental work was based on mass, kinetic energy distributions, neutron and X-ray emission in thermal neutron fission of 235U, which were carried out with indigenously developed detectors and electronics instrumentation. With the commissioning of CIRUS reactor and the availability of higher neutron flux, advanced experiments were carried out on ternary fission, pre-scission neutron emission, fragment charge distributions, quarternary fission, etc. In the late eighties, heavy-ion beams from the pelletron-based medium energy heavy-ion accelerator were available, which provided a rich variety of possibilities in nuclear fission studies. Pioneering work on fragment angular distributions, fission time-scales, transfer-induced fission, -ray multiplicities and mass–energy correlations were carried out, providing important information on the dynamics of the fission process. More recently, work on fission fragment -ray spectroscopy has been initiated, to understand the nuclear structure aspects of the neutron-rich fission fragment nuclei. There have also been parallel efforts to carry out theoretical studies in the areas of shell effects, superheavy nuclei, fusion–fission dynamics, fragment angular distributions, etc. to complement the experimental studies. This paper will provide a glimpse of the work carried out by the fission group at Trombay in the above-mentioned topics.

  13. Fission excitation function for 19F + 194,196,198Pt at near and above barrier energies

    Directory of Open Access Journals (Sweden)

    Singh Varinderjit

    2015-01-01

    Full Text Available Fission excitation functions for 19F + 194,196,198Pt reactions populating 213,215,217Fr compound nuclei are reported. Out of these three compound nuclei, 213Fr is a shell closed (N=126 compound nucleus and the other two are away from the shell closure. From a comparison of the experimental fission cross-sections with the statistical model predictions, it is observed that the fission cross-sections are underestimated by the statistical model predictions using shell corrected finite range rotating liquid drop model (FRLDM fission barriers. Further the FRLDM fission barriers are reduced to fit the fission cross-sections over the entire measured energy range.

  14. Even-odd effects and Coulomb effects on minimal excitation energy of fragments from low energy fission

    CERN Document Server

    Montoya, Modesto

    2014-01-01

    This work is focused on even-odd effects on the minimal total fragment excitation energy in thermal neutron induced fission of 233U and 235U as well as in spontaneous fission of 252Cf. In a scission model, taking into account the fragment deformation properties and Coulomb interaction between fragments, the expression of the difference between Q-values referred to even/even and odd/odd charge splits, respectively, on the corresponding difference between the minimal total fragment excitation energy is studied.

  15. Fission nuclear power prospects and its role in meeting global energy needs

    International Nuclear Information System (INIS)

    Nuclear power currently makes an important contribution to world's energy requirements providing 17% of its electricity. But as global warming becomes of greater concern, many ask whether nuclear power can and should contribute more. The author, who is involved in the nuclear power enterprise for 35 years, tries to answer this question affirmative. He holds the view that: a) nuclear fission power is essential to meeting world's energy needs without unduly impairing the global environment; b) by possessing the required attributes discussed in this paper, nuclear fission power can be made societally acceptable; c) the industrialized world should accelerate LMFR deployment while fostering more convenient energy alternatives for the developing world; and d) the HTGR is unique in its ability to augment non-electricity energy needs and could become the technology choice of developing countries for nuclear electricity production. (author). 5 refs., 5 figs., 4 tabs

  16. Fusion-Fission of $^{16}O+^{197}Au$ at Sub-Barrier Energies

    CERN Document Server

    Back, B B; Janssens, R V F; Henderson, D J; Shumard, B R; Lister, C J; Peterson, D; Rehm, K E; Tanihata, I; Tang, X; Wang, X; Zhu, S

    2006-01-01

    The recent discovery of heavy-ion fusion hindrance at far sub-barrier energies has focused much attention on both experimental and theoretical studies of this phenomenon. Most of the experimental evidence comes from medium-heavy systems such as Ni+Ni to Zr+Zr, for which the compound system decays primarily by charged-particle evaporation. In order to study heavier systems, it is, however, necessary to measure also the fraction of the decay that goes into fission fragments. In the present work we have, therefore, measured the fission cross section of 16O+197Au down to unprecedented far sub-barrier energies using a large position sensitive PPAC placed at backward angles. The preliminary cross sections will be discussed and compared to earlier studies at near-barrier energies. No conclusive evidence for sub-barrier hindrance was found, probably because the measurements were not extended to sufficiently low energies.

  17. Advanced Space Power Systems (ASPS): Advanced Energy Storage Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The development of high specific energy devices will enable NASA’s future robotic and human-exploration missions.  The need for advances in energy...

  18. Influence of complete energy sorting on the characteristics of the odd-even effect in fission-fragment element distributions

    CERN Document Server

    Jurado, Beatriz

    2014-01-01

    The characteristics of the odd-even effect in fission-fragment Z distributions are compared to a model based on statistical mechanics. Special care is taken for using a consistent description for the influence of pairing correlations on the nuclear level density. The variation of the odd-even effect with the mass of the fissioning nucleus and with fission asymmetry is explained by the important statistical weight of configurations where the light nascent fission fragment populates the lowest energy state of an even-even nucleus. This implies that entropy drives excitation energy and unpaired nucleons predominantly to the heavy fragment. Therefore, within our model, the odd-even effect appears as an additional signature of the recently discovered energy-sorting process in nuclear fission.

  19. FITPULS: a code for obtaining analytic fits to aggregate fission-product decay-energy spectra. [In FORTRAN

    Energy Technology Data Exchange (ETDEWEB)

    LaBauve, R.J.; George, D.C.; England, T.R.

    1980-03-01

    The operation and input to the FITPULS code, recently updated to utilize interactive graphics, are described. The code is designed to retrieve data from a library containing aggregate fine-group spectra (150 energy groups) from fission products, collapse the data to few groups (up to 25), and fit the resulting spectra along the cooling time axis with a linear combination of exponential functions. Also given in this report are useful results for aggregate gamma and beta spectra from the decay of fission products released from /sup 235/U irradiated with a pulse (10/sup -4/ s irradiation time) of thermal neutrons. These fits are given in 22 energy groups that are the first 22 groups of the LASL 25-group decay-energy group structure, and the data are expressed both as MeV per fission second and particles per fission second; these pulse functions are readily folded into finite fission histories. 65 figures, 11 tables.

  20. 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.

  1. Fission product retention in the ACACIA (AdvanCed Atomic Cogenerator for Industrial Applications) reactor primary system

    International Nuclear Information System (INIS)

    The transport and deposition of fission products in the ACACIA (AdvanCed Atomic Cogenerator for Industrial Applications) high temperature reactor primary system are investigated. The study focuses on the behaviour calculated with the MELCOR computer code of 4 nuclides: Cs-137, Sr-90, Ag-110m, and I-131. After a ten-year operation period, the total activity of the released nuclides in the primary system is about 58 GBq. The highest activity is produced by Cs-137 (52 GBq), followed by I-131 (4 GBq), and Ag-110m (1.8 GBq). The contribution of Sr-90 is very low (1600 Bq). The highest activity is found in the precooler (56 GBq). The main reason is the condensation of the volatile species CsOH and CsI in this component. Other components with high activities are the recuperator (1.4 GBq) and the compressor (0.007 GBq). These components are contaminated by Ag-110m. The gas ducts in the energy conversion unit are contaminated by Ag-110m (0.043 GBq) and I-131 (0.011 GBq). Contamination as a consequence of a Loss Of Coolant Accident (LOCA) or a Loss of Flow Accident (LOFA) is difficult to estimate, because it depends on a number of phenomena. Under the assumption that 10 fuels elements are damaged, the activity is about 44 GBq. In this accident, Ag-110m produces most of the activity (31 GBq), followed by Cs-137 (12 GBq), and I-131 (1.4 GBq). Although the activity of Sr-90 is high (0.023 GBq), it is negligible compared to the activity of the other nuclides. Obviously, the activity is proportional to the number of damaged fuel elements. The distribution of the nuclides over the components is not considered in view of the large number of uncertainties. 9 refs

  2. Microscopic approach of fission dynamics applied to fragment kinetic energy and mass distributions in 238U

    OpenAIRE

    Goutte, H.; Berger, J.F.; Casoli, P.; Gogny, D.

    2005-01-01

    The collective dynamics of low energy fission in 238U is described within a time-dependent formalism based on the Gaussian Overlap Approximation of the time-dependent Generator Coordinate Method. The intrinsic deformed configurations of the nucleus are determined from the self-consistent Hartree-Fock-Bogoliubov procedure employing the effective force D1S with constraints on the quadrupole and octupole moments. Fragment kinetic energy and mass distributions are calculated and compared with exp...

  3. Unfolding the fission prompt γ-ray energy and multiplicity distribution measured by DANCE

    International Nuclear Information System (INIS)

    The nearly energy independence of the γ-ray efficiency and multiplicity response for the DANCE array, the unusual characteristic elucidated in our early technical report (LLNL-TR-452298), gives one a unique opportunity to derive the true prompt γ-ray energy and multiplicity distribution in fission from the measurement. This unfolding procedure for the experimental data will be described in details and examples will be given to demonstrate the feasibility of reconstruction of the true distribution.

  4. Unfolding the fission prompt gamma-ray energy and multiplicity distribution measured by DANCE

    Energy Technology Data Exchange (ETDEWEB)

    Chyzh, A; Wu, C Y; Bredeweg, T; Couture, A; Jandel, M; Ullmann, J; Laptev, A

    2010-10-16

    The nearly energy independence of the {gamma}-ray efficiency and multiplicity response for the DANCE array, the unusual characteristic elucidated in our early technical report (LLNL-TR-452298), gives one a unique opportunity to derive the true prompt {gamma}-ray energy and multiplicity distribution in fission from the measurement. This unfolding procedure for the experimental data will be described in details and examples will be given to demonstrate the feasibility of reconstruction of the true distribution.

  5. On the role of energy separated in fission process, excitation energy and reaction channels effects in the isomeric ratios of fission product 135Xe in photofission of actinide elements

    Science.gov (United States)

    Thiep, Tran Duc; An, Truong Thi; Cuong, Phan Viet; Vinh, Nguyen The; Mishinski, G. V.; Zhemenik, V. I.

    2016-07-01

    In this work we present the isomeric ratio of fission product 135Xe in the photo-fission of actinide elements 232Th, 233U and 237Np induced by end-point bremsstrahlung energies of 13.5, 23.5 and 25.0 MeV which were determined by the method of inert gaseous flow. The data were analyzed, discussed and compared with the similar data from literature to examine the role of energy separated in fission process, excitation energy and reaction channels effects.

  6. Nanocarbons for advanced energy storage

    CERN Document Server

    Feng, Xinliang

    2015-01-01

    This first volume in the series on nanocarbons for advanced applications presents the latest achievements in the design, synthesis, characterization, and applications of these materials for electrochemical energy storage. The highly renowned series and volume editor, Xinliang Feng, has put together an internationally acclaimed expert team who covers nanocarbons such as carbon nanotubes, fullerenes, graphenes, and porous carbons. The first two parts focus on nanocarbon-based anode and cathode materials for lithium ion batteries, while the third part deals with carbon material-based supercapacit

  7. Advanced materials for clean energy

    CERN Document Server

    Xu (Kyo Jo), Qiang

    2015-01-01

    Arylamine-Based Photosensitizing Metal Complexes for Dye-Sensitized Solar CellsCheuk-Lam Ho and Wai-Yeung Wongp-Type Small Electron-Donating Molecules for Organic Heterojunction Solar CellsZhijun Ning and He TianInorganic Materials for Solar Cell ApplicationsYasutake ToyoshimaDevelopment of Thermoelectric Technology from Materials to GeneratorsRyoji Funahashi, Chunlei Wan, Feng Dang, Hiroaki Anno, Ryosuke O. Suzuki, Takeyuki Fujisaka, and Kunihito KoumotoPiezoelectric Materials for Energy HarvestingDeepam Maurya, Yongke Yan, and Shashank PriyaAdvanced Electrode Materials for Electrochemical Ca

  8. Theoretical Description of the Fission Process

    International Nuclear Information System (INIS)

    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

  9. Theory of neutron emission in fission

    International Nuclear Information System (INIS)

    Following a summary of the observables in neutron emission in fission, a brief history is given of theoretical representations of the prompt fission neutron spectrum N(E) and average prompt neutron multiplicity bar νp. This is followed by descriptions, together with examples, of modern approaches to the calculation of these quantities including recent advancements. Emphasis will be placed upon the predictability and accuracy of the modern approaches. In particular, the dependence of N(E) and bar νp on the fissioning nucleus and its excitation energy will be discussed, as will the effects of and competition between first-, second- and third-chance fission in circumstances of high excitation energy. Finally, properties of neutron-rich (fission-fragment) nuclei are discussed that must be better known to calculate N(E) and bar νp with higher accuracy than is currently possible

  10. The Complete Burning of Weapons Grade Plutonium and Highly Enriched Uranium with (Laser Inertial Fusion-Fission Energy) LIFE Engine

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J C; Diaz de la Rubia, T; Moses, E

    2008-12-23

    The National Ignition Facility (NIF) project, a laser-based Inertial Confinement Fusion (ICF) experiment designed to achieve thermonuclear fusion ignition and burn in the laboratory, is under construction at the Lawrence Livermore National Laboratory (LLNL) and will be completed in April of 2009. Experiments designed to accomplish the NIF's goal will commence in late FY2010 utilizing laser energies of 1 to 1.3 MJ. Fusion yields of the order of 10 to 20 MJ are expected soon thereafter. Laser initiated fusion-fission (LIFE) engines have now been designed to produce nuclear power from natural or depleted uranium without isotopic enrichment, and from spent nuclear fuel from light water reactors without chemical separation into weapons-attractive actinide streams. A point-source of high-energy neutrons produced by laser-generated, thermonuclear fusion within a target is used to achieve ultra-deep burn-up of the fertile or fissile fuel in a sub-critical fission blanket. Fertile fuels including depleted uranium (DU), natural uranium (NatU), spent nuclear fuel (SNF), and thorium (Th) can be used. Fissile fuels such as low-enrichment uranium (LEU), excess weapons plutonium (WG-Pu), and excess highly-enriched uranium (HEU) may be used as well. Based upon preliminary analyses, it is believed that LIFE could help meet worldwide electricity needs in a safe and sustainable manner, while drastically shrinking the nation's and world's stockpile of spent nuclear fuel and excess weapons materials. LIFE takes advantage of the significant advances in laser-based inertial confinement fusion that are taking place at the NIF at LLNL where it is expected that thermonuclear ignition will be achieved in the 2010-2011 timeframe. Starting from as little as 300 to 500 MW of fusion power, a single LIFE engine will be able to generate 2000 to 3000 MWt in steady state for periods of years to decades, depending on the nuclear fuel and engine configuration. Because the fission

  11. The Complete Burning of Weapons Grade Plutonium and Highly Enriched Uranium with (Laser Inertial Fusion-Fission Energy) LIFE Engine

    International Nuclear Information System (INIS)

    The National Ignition Facility (NIF) project, a laser-based Inertial Confinement Fusion (ICF) experiment designed to achieve thermonuclear fusion ignition and burn in the laboratory, is under construction at the Lawrence Livermore National Laboratory (LLNL) and will be completed in April of 2009. Experiments designed to accomplish the NIF's goal will commence in late FY2010 utilizing laser energies of 1 to 1.3 MJ. Fusion yields of the order of 10 to 20 MJ are expected soon thereafter. Laser initiated fusion-fission (LIFE) engines have now been designed to produce nuclear power from natural or depleted uranium without isotopic enrichment, and from spent nuclear fuel from light water reactors without chemical separation into weapons-attractive actinide streams. A point-source of high-energy neutrons produced by laser-generated, thermonuclear fusion within a target is used to achieve ultra-deep burn-up of the fertile or fissile fuel in a sub-critical fission blanket. Fertile fuels including depleted uranium (DU), natural uranium (NatU), spent nuclear fuel (SNF), and thorium (Th) can be used. Fissile fuels such as low-enrichment uranium (LEU), excess weapons plutonium (WG-Pu), and excess highly-enriched uranium (HEU) may be used as well. Based upon preliminary analyses, it is believed that LIFE could help meet worldwide electricity needs in a safe and sustainable manner, while drastically shrinking the nation's and world's stockpile of spent nuclear fuel and excess weapons materials. LIFE takes advantage of the significant advances in laser-based inertial confinement fusion that are taking place at the NIF at LLNL where it is expected that thermonuclear ignition will be achieved in the 2010-2011 timeframe. Starting from as little as 300 to 500 MW of fusion power, a single LIFE engine will be able to generate 2000 to 3000 MWt in steady state for periods of years to decades, depending on the nuclear fuel and engine configuration. Because the fission blanket in a fusion-fission

  12. Parity nonconservation in nuclear fission: does it depend on fragment mass/energy?

    International Nuclear Information System (INIS)

    For fission of 233U induced by polarized cold neutrons the dependence of the PNC asymmetry coefficient αnf(mLF, TKE) on light fragment mass mLF and total kinetic energy TKE was studied. Concurrently the angular distribution predicted for PNC reactions was tested. Altogether more than 2x1010 fission events with high mass/energy resolution have been collected. This corresponds to an increase in the statistics compared to previous experiments (U. Graf, F. Goennenwein, P. Geltenbort, et al., Z. Phys. A 351 (1995) 281 and V.A. Vesna, V.A. Knyaz'kov, E.A. Kolomenskii et al., JETP. Lett. 31 (1980) 663) by a factor of about 20. The preliminary analysis of the PNC asymmetry shows no significant variation of αnf for different fragment masses/energies, whereas the prediction concerning the angular dependence was confirmed with a precision not obtained up to now

  13. Fission rates measured using high-energy gamma-rays from short half-life fission products in fresh and spent nuclear fuel

    International Nuclear Information System (INIS)

    In recent years, higher discharge burn-ups and initial fuel enrichments have led to more and more heterogeneous core configurations in light water reactors (LWRs), especially at the beginning of cycle when fresh fuel assemblies are loaded next to highly burnt ones. As this trend is expected to continue in the future, the Paul Scherrer Institute has, in collaboration with the Swiss Association of Nuclear Utilities, swissnuclear, launched the experimental programme LIFE(at)PROTEUS. The LIFE(at)PROTEUS programme aims to better characterise interfaces between burnt and fresh UO2 fuel assemblies in modern LWRs. Thereby, a novel experimental database is to be made available for enabling the validation of neutronics calculations of strongly heterogeneous LWR core configurations. During the programme, mixed fresh and highly burnt UO2 fuel lattices will be investigated in the zero-power research reactor PROTEUS. One of the main types of investigations will be to irradiate the fuel in PROTEUS and measure the resulting fission rate distributions across the interface between fresh and burnt fuel zones. The measurement of fission rates in burnt fuel re-irradiated in a zero-power reactor requires, however, the development of new experimental techniques which are able to discriminate against the high intrinsic activity of the fuel. The principal goal of the present research work has been to develop such a new measurement technique. The selected approach is based on the detection of high-energy gamma-ray lines above the intrinsic background (i.e. above 2200 keV), which are emitted by short-lived fission products freshly created in the fuel. The fission products 88Kr, 142La, 138Cs, 84Br, 89Rb, 95Y, 90mRb and 90Rb, with half-lives between 2.6 min and 2.8 h, have been identified as potential candidates. During the present research work, the gamma-ray activity of short-lived fission products has, for the first time, been measured and quantitatively evaluated for re-irradiated burnt UO

  14. Even-odd effects and Coulomb effects on minimal excitation energy of fragments from low energy fission

    OpenAIRE

    Montoya, Modesto

    2014-01-01

    This work is focused on even-odd effects on the minimal total fragment excitation energy in thermal neutron induced fission of 233U and 235U as well as in spontaneous fission of 252Cf. In a scission model, taking into account the fragment deformation properties and Coulomb interaction between fragments, the expression of the difference between Q-values referred to even/even and odd/odd charge splits, respectively, on the corresponding difference between the minimal total fragment excitation e...

  15. Total kinetic energy release in the fast neutron-induced fission of $^{235}$U

    CERN Document Server

    Yanez, R; King, J; Barrett, J S; Fotiades, N; Lee, H Y

    2015-01-01

    We have measured the total kinetic energy (TKE) release for the $^{235}$U(n,f) reaction for $E_{n}$=2-100 MeV using the 2E method with an array of Si PIN diode detectors. The neutron energies were determined by time of flight measurements using the white spectrum neutron beam at the LANSCE facility. (To calibrate the apparatus, the TKE release for $^{235}$U(n$_{th}$,f) was also measured using a thermal neutron beam from the OSU TRIGA reactor). The TKE decreases non-linearly from 169.0 MeV to 161.4 MeV for $E_{n}$=2-90 MeV. The standard deviation of the TKE distribution is constant from $E_{n}$=20-90 MeV. Comparison of the data with the multi-modal fission model of Brosa indicates the TKE decrease is a consequence of the growth of symmetric fission and the corresponding decrease of asymmetric fission with increasing neutron energy. The average TKE associated with the Brosa superlong, standard I and standard II modes for a given mass is independent of neutron energy.

  16. Development of technetium alloy waste forms for advanced nuclear energy cycles

    International Nuclear Information System (INIS)

    The Fuel Cycle Technologies (FCT) Program within the Office of Nuclear Energy of the U.S. Department of Energy is charged with developing nuclear fuel cycle options that improve use of actinide resources, responsibly manage wastes, improve and limit proliferation risk. Technetium is a fission product of particular concern for disposal in a repository because of its high fission yield, long half-life, and high solubility and mobility in groundwater as pertechnetate. For example, modeling studies for the former Yucca Mountain repository site indicated that technetium would be an important dose contributor after closure of the repository, in the first 10,000 years. The FCT Program is investigating a range of potential repository environments for ultimate disposal of fission products including technetium from advanced nuclear fuel recycling schemes

  17. Advanced Energy Projects FY 1990 research summaries

    International Nuclear Information System (INIS)

    This report serves as a guide to prepare proposals and provides summaries of the research projects active in FY 1990, sponsored by the Office of Basic Energy Sciences Division of Advanced Energy Projects, Department of Energy. (JF)

  18. Singlet Fission

    Czech Academy of Sciences Publication Activity Database

    Smith, M. B.; Michl, Josef

    2010-01-01

    Roč. 110, č. 11 (2010), s. 6891-6936. ISSN 0009-2665 Grant ostatní: Department of Energy(US) DE-FG36-08GO18017 Institutional research plan: CEZ:AV0Z40550506 Keywords : solar energy conversion * photovoltaics * singlet fission Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 33.033, year: 2010

  19. Systems Modeling For The Laser Fusion-Fission Energy (LIFE) Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Meier, W R; Abbott, R; Beach, R; Blink, J; Caird, J; Erlandson, A; Farmer, J; Halsey, W; Ladran, T; Latkowski, J; MacIntyre, A; Miles, R; Storm, E

    2008-10-02

    A systems model has been developed for the Laser Inertial Fusion-Fission Energy (LIFE) power plant. It combines cost-performance scaling models for the major subsystems of the plant including the laser, inertial fusion target factory, engine (i.e., the chamber including the fission and tritium breeding blankets), energy conversion systems and balance of plant. The LIFE plant model is being used to evaluate design trade-offs and to identify high-leverage R&D. At this point, we are focused more on doing self consistent design trades and optimization as opposed to trying to predict a cost of electricity with a high degree of certainty. Key results show the advantage of large scale (>1000 MWe) plants and the importance of minimizing the cost of diodes and balance of plant cost.

  20. An ionization chamber with Frisch grids for studies of high-energy neutron-induced fission

    Science.gov (United States)

    Tutin, G. A.; Ryzhov, I. V.; Eismont, V. P.; Kireev, A. V.; Condé, H.; Elmgren, K.; Olsson, N.; Renberg, P.-U.

    2001-01-01

    A gridded ionization chamber for fission fragment detection is described. The chamber has been specially designed for use at the quasi-monoenergetic 7Li(p, n) neutron source at the The Svedberg Laboratory, Uppsala, Sweden. The detector permits measurements of fission fragment energy and emission angle for two targets with diameter of up to 10 cm. The time response of the chamber (⩽5 ns FWHM) is adequate to apply time-of-flight discrimination against background events induced by non-peak neutrons. Results of angular anisotropy measurements for the 232Th (n, f) and 238U(n, f) reactions in the 20-160 MeV energy range are given.

  1. Measurement of fragment mass distributions in neutron-induced fission reactions at intermediate energies

    Science.gov (United States)

    Simutkin, V. D.; Ryzhov, I. V.; Tutin, G. A.; Vaishnene, L. A.; Blomgren, J.; Pomp, S.; Österlund, M.; Andersson, P.; Bevilacqua, R.; Meulders, J. P.; Prieels, R.

    2009-10-01

    Fragment mass distributions from neutron-induced fission of 232Th and 238U have been measured at quasi-monoenergetic neutron beam of the Louvain-la-Neuve cyclotron facility CYCLONE. The measurements have been carried out making use of a multi-section Frisch-gridded ionization chamber. The measurement technique as well as the data processing is described. Preliminary data on primary fragment mass yields are given for an incident neutron energy of 32.8 MeV.

  2. Double-energy double-velocity measurement system for fission fragments and its application

    International Nuclear Information System (INIS)

    A new system of double-energy double-velocity (DEDV) measurement for fission fragments has been developed. In this system, the energies of fission fragments are measured by silicon surface barrier detectors (SSB) and the velocities by the time-of-flight (TOF) method utilizing thin film detectors (TFD) as start detectors and SSBs as stop detectors of TOF. Theoretical and experimental studies on TFDs and SSBs have been performed before the construction of the DEDV measurement system. The TFD consists of a thin plastic scintillator film and light guide. The author proposes a new model of the luminescence production in a scintillator film. This model takes into account the thickness of the scintillator film and uses only one parameter. The calculated TFD response to charged particles shows good agreement with other experiments. The dependence of the TFD response to the thickness of the scintillator film has been studied experimentally and analyzed by the luminescence production model. The results of this analysis shows the validity of the luminescence production model. The time resolution of the DEDV measurement system using TFDs and SSBs was 133 ps. As an application of this system, the DEDV measurement for the thermal neutron-induced fission of 233U has been carried out at the super mirror neutron guide tube facility of Kyoto University Reactor (KUR). The energy and velocity of each fission fragment have been stored on magnetic disk event by event in a list mode. The analyzed results of masses, energies and velocities of light and heavy fragments agree well with other authors' works. The value of the total neutron emission number is 2.53 and shows good agreement within experimental error, with the JENDL-2 value, 2.49. The light fragment shows a slightly greater number of neutrons emitted than the other works. This suggests the possibility of larger deformation of light fragments at the scission point. (author)

  3. Measurement of the energy spectra of fission fragments using nuclear track detectors and digital image processing

    International Nuclear Information System (INIS)

    Energy spectra of fission fragments were determined using a Nuclear Track Methodology (NTM) supported by digital image analysis and numerical data processing using a standard personal computer. The analysis of a californium (252Cf) spectrum with this approach shows improvement compared with the values reported previously using the standard procedure, in terms of resolution and accuracy. This new method adds full automation to the technical advantages and cost effectiveness of an NTM.

  4. Study of Relationship Between Neutron Energy and Fission Yields of 95Zr, 140Ba and 147Nd From 235U

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This work measures fission yields of 235U induced by neutrons with energy of thermal, 3.0, 5.0, 5.5, 8.0 and 14.8 MeV. The main purpose is to study the relationship between neutron energy and fission fields of 95Zr,140Ba and 147Nd from 235U by measuring the radioactivity of foil with direct gamma spectrometry. The fission yields induced by fast neutrons are get by fast-thermal-ratio method which based on yields from thermal neutrons, yields by thermal neutron are come from absolute measurement. Since fast-thermal-ratio method eliminates uncertainties of gamma intensity, gamma

  5. Measurements of charge distributions of the fragments in the low energy fission reaction

    International Nuclear Information System (INIS)

    The measurement for charge distributions of fragments in spontaneous fission 252Cf has been performed by using a unique style of detector setup consisting of a typical grid ionization chamber and a ΔΕ−Ε particle telescope, in which a thin grid ionization chamber served as the ΔΕ-section and the E-section was an Au–Si surface barrier detector. The typical physical quantities of fragments, such as mass number and kinetic energies as well as the deposition in the gas ΔΕ detector and E detector were derived from the coincident measurement data. The charge distributions of the light fragments for the fixed mass number A2⁎ and total kinetic energy (TKE) were obtained by the least-squares fits for the response functions of the ΔΕ detector with multi-Gaussian functions representing the different elements. The results of the charge distributions for some typical fragments are shown in this article which indicates that this detection setup has the charge distribution capability of Ζ:ΔΖ>40:1. The experimental method developed in this work for determining the charge distributions of fragments is expected to be employed in the neutron induced fissions of 232Th and 238U or other low energy fission reactions.

  6. Some important aspects of fragment angular momentum in medium energy fission of 238U

    International Nuclear Information System (INIS)

    Independent isomeric yield ratios of 131Te, 133Te and 134I have been determined at five different energies in the range of 25-44 MeV alpha particle induced fission of 238U using radiochemical and gamma spectrometric techniques. From the independent isomeric yield ratios, fragment angular momenta (Jrms) have been deduced using a statistical model analysis. The Jrms were also calculated theoretically based on thermal equilibration of various collective modes after considering the occurrence of multichance fission. These data and the literature data for various fragments in the mass region 126-136 in 238U (α,f), 238U (p,f) and 238U (γ,f) show the following important features: (i) Both the entrance channel excitation energy and input angular momentum affect the fragment angular momentum in the exit channel. (ii) There are two groups of fission products from the point of view of change of fragment angular momentum with increase in excitation energy and input angular momentum. (iii) Fragment angular momentum depends on nuclear structure effect such as shell closure proximity and odd-even effect. (iv) The fragment angular momentum calculated theoretically based on statistical equilibration of various collective modes are in good agreement with the experimental values indicating the validity of such an assumption

  7. Direct energy conversion in fission reactors: A U.S. NERI project

    Energy Technology Data Exchange (ETDEWEB)

    SLUTZ,STEPHEN A.; SEIDEL,DAVID B.; POLANSKY,GARY F.; ROCHAU,GARY E.; LIPINSKI,RONALD J.; BESENBRUCH,G.; BROWN,L.C.; PARISH,T.A.; ANGHAIE,S.; BELLER,D.E.

    2000-05-30

    In principle, the energy released by a fission can be converted directly into electricity by using the charged fission fragments. The first theoretical treatment of direct energy conversion (DEC) appeared in the literature in 1957. Experiments were conducted over the next ten years, which identified a number of problem areas. Research declined by the late 1960's due to technical challenges that limited performance. Under the Nuclear Energy Research Initiative the authors are determining if these technical challenges can be overcome with todays technology. The authors present the basic principles of DEC reactors, review previous research, discuss problem areas in detail, and identify technological developments of the last 30 years that can overcome these obstacles. As an example, the fission electric cell must be insulated to avoid electrons crossing the cell. This insulation could be provided by a magnetic field as attempted in the early experiments. However, from work on magnetically insulated ion diodes they know how to significantly improve the field geometry. Finally, a prognosis for future development of DEC reactors will be presented .

  8. Direct energy conversion in fission reactors: A U.S. NERI project

    International Nuclear Information System (INIS)

    In principle, the energy released by a fission can be converted directly into electricity by using the charged fission fragments. The first theoretical treatment of direct energy conversion (DEC) appeared in the literature in 1957. Experiments were conducted over the next ten years, which identified a number of problem areas. Research declined by the late 1960's due to technical challenges that limited performance. Under the Nuclear Energy Research Initiative the authors are determining if these technical challenges can be overcome with todays technology. The authors present the basic principles of DEC reactors, review previous research, discuss problem areas in detail, and identify technological developments of the last 30 years that can overcome these obstacles. As an example, the fission electric cell must be insulated to avoid electrons crossing the cell. This insulation could be provided by a magnetic field as attempted in the early experiments. However, from work on magnetically insulated ion diodes they know how to significantly improve the field geometry. Finally, a prognosis for future development of DEC reactors will be presented

  9. Total kinetic energy release in the fast neutron-induced fission of $^{235}$U

    CERN Document Server

    Yanez, R; King, J; Barrett, J S; Fotiades, N; Lee, H Y

    2016-01-01

    We have measured the total kinetic energy (TKE) release for the $^{235}$U(n,f) reaction for $E_{n}$=2-100 MeV using the 2E method with an array of Si PIN diode detectors. The neutron energies were determined by time of flight measurements using the white spectrum neutron beam at the LANSCE facility. To benchmark the TKE measurement, the TKE release for $^{235}$U(n$_{th}$,f) was also measured using a thermal neutron beam from the Oregon State University TRIGA reactor, giving pre-neutron emission $E^*_{TKE}=170.7\\pm0.4$ MeV in good agreement with known values. Our measurements are thus absolute measurements. The TKE in $^{235}$U(n,f) decreases non-linearly from 169.0 MeV to 161.4 MeV for $E_{n}$=2-90 MeV. Comparison of the data with the multi-modal fission model of Brosa indicates the TKE decrease is a consequence of the growth of symmetric fission and the corresponding decrease of asymmetric fission with increasing neutron energy. The average TKE associated with the Brosa superlong, standard I and standard II ...

  10. Kinetic energies of cluster fragments in ternary fission of 252 Cf

    Science.gov (United States)

    Vijayaraghavan, K. R.; von Oertzen, W.; Balasubramaniam, M.

    2012-03-01

    The kinetic energy distribution and potential energies of fragments from the collinear cluster tripartition (CCT), the "true" ternary fission of 252Cf, have been calculated. It is assumed that the breakup of the nucleus into three fragments happens sequentially in two steps from a hyper-deformed shape. In the first step a first neck rupture occurs of the parent radioactive nucleus, forming two fragments (one of them is usually 132Sn) and, in the second step, one of the two fragments breaks into two other fragments, resulting finally in three fragments (the experiment is based on a binary coincidence where a missing mass is determined). We show the result for the principal combination of the three spherical fragments (semi-magic isotopes of Sn, Ca, Ni) observed recently experimentally. These isotopes are clusters with high Q -values, which produce the highest yields in the ternary fission bump. It is shown that the kinetic energies of the middle fragments have very low values, making their experimental detection quite difficult. This fact explains why the direct detection of true ternary fission with three fragments heavier than A > 40 has escaped experimental observation.

  11. Statistical and evaporation models for the neutron emission energy spectrum in the center-of-mass system from fission fragments

    International Nuclear Information System (INIS)

    The neutron emission energy spectra in the CMS (center-of-mass) frame from two compound nuclei produced by fission are studied. The neutron spectra calculated with the Hauser–Feshbach statistical model are compared with the evaporation theory, and the definition of the temperature is revisited. Using the Monte Carlo technique we average the CMS neutron spectra from many fission fragments to construct the representative CMS spectrum from both the light and heavy fragments. The CMS spectra for each fission fragment pair are also converted into the laboratory frame to calculate the total prompt fission neutron spectrum that can be observed experimentally. This is compared to measured laboratory data for thermal neutron induced fission on 235U. We show that the Hauser–Feshbach calculation gives a different spectrum shape than the Madland–Nix model calculation

  12. Prompt Fission Gamma-ray Studies at DANCE

    Science.gov (United States)

    Jandel, M.; Rusev, G.; Bond, E. M.; Bredeweg, T. A.; Chadwick, M. B.; Couture, A.; Fowler, M. M.; Haight, R. C.; Kawano, T.; Keksis, A. L.; Mosby, S. M.; O'Donnell, J. M.; Rundberg, R. S.; Stetcu, I.; Talou, P.; Ullmann, J. L.; Vieira, D. J.; Wilhelmy, J. B.; Stoyer, M. A.; Haslett, R. J.; Henderson, R. A.; Becker, J. A.; Wu, C. Y.

    Measurements of correlated data on prompt-fission γ-rays (PFG) have been carried out for various actinide isotopes in recent years using the Detector for Advanced Neutron Capture Experiments (DANCE) at Los Alamos National Laboratory (LANL). We have developed a model that conveniently parametrizes the correlated data of γ-ray multiplicity and energy. New results on two- dimensional prompt-fission γ-ray multiplicity versus energy distributions from spontaneous fission on 252Cf and neutron-induced fission on 242mAm are presented together with previously obtained results on 233,235U and 239Pu. Correlated PFG data from 252Cf are also compared to results of the detailed theoretical model developed at LANL, for different thresholds of PFG energies. Future plans to measure correlated data on fission fragments, prompt fission neutrons and γ-rays at DANCE are presented.

  13. Effect of volume ratio between uranium and water on fusion-fission hybrid for energy production

    International Nuclear Information System (INIS)

    The theoretic model of MCORGS code, which is used in this paper to evaluate the effect of the volume ratio between uranium and water (VR) on a fusion-fission hybrid for energy production, is introduced. It is showed that at natural uranium case, the VR of 2:1 is preferred, since it can reach a comprise between energy multiplication and tritium breeding ratio, and the neutronics performance of the system can maintain more than 100 years. At the case of spent fuel from PWR, there are more room for selection of VR. Both energy multiplication and tritium breeding ratio will improve, however the fissile material breeding capacity will degrade. (authors)

  14. Effect of the fragment excitation energy distribution on the prompt fission neutron spectrum

    International Nuclear Information System (INIS)

    The effects of cascade emission of neutrons from a nucleus and of distribution of the initial excitation energy upon characteristics of the emission spectrum are studied. Calculations of the emission spectrum are made in the Weisskopf form in the constant temperature approximation. It has been elucidated that the cascade character of particle emission is not sufficient for the total spectrum to approach the maxwellian one. A dependence of the distorting function upon energy has been obtained. The calculation spectrum is compared with the experimental and with the Weisskopf spectra. A conclusion is drawn that the temperature dependence upon excitation energy is predominant in formation of a fission neutron spectrum

  15. Total fission cross section of {sup 181}Ta and {sup 208}Pb induced by protons at relativistic energies

    Energy Technology Data Exchange (ETDEWEB)

    Ayyad, Y.; Benlliure, J.; Casarejos, E. [Group GENP, Dpto. Fisica de Particulas, Universidade de Santiago de Compostela, 15782 Santiago de Compostela (Spain); Schmidt, K. H. [GSI, Planckstrasse 1, 64941, Darmstadt (Germany); Jurado, B. [Universite Bordeaux I, CNRS/IN2 P3, CENBG, BP 120, F-33175 Gradignan (France); Kelic-Heil, A. [GSI, Planckstrasse 1, 64941, Darmstadt (Germany); Pol, H. A. [Group GENP, Dpto. Fisica de Particulas, Universidade de Santiago de Compostela, 15782 Santiago de Compostela (Spain); Ricciardi, M. V.; Pleskac, R. [GSI, Planckstrasse 1, 64941, Darmstadt (Germany); Enqvist, T. [CUPP Project, P.O. Box 22, FI-86801, Pyhsalmi (Finland); Rejmund, F. [Grand Accelerateur National D Ions Lourds, BP 55027, F-14076 Caen Cedex 05 (France); Giot, L. [Subatech - Ecole des Mines de Nantes (France); Henzl, V. [Massachusetts Inst. of Technology, 77, Massachusetts Ave, Cambridge, MA 02139 (United States); Lukic, S. [Karlsruhe Inst. of Technology, D-76021 Karlsruhe (Germany); Ngoc, S. N. [Dept. of Nuclear Physics, Inst. of Physics, National Centre for Natural Science and Technology, NgiaDo-TuLiem, Hanoi (Viet Nam); Boudard, A. [DSM/IRFU/CEA, 91191 Gif-sur-Ivette (France); Universite Louis Pasteur, Strasbourg (France); Leray, S. [DSM/IRFU/CEA, 91191 Gif-sur-Ivette (France); Fernandez, M. [Entro de Investigaciones Energticas Medioambientales Y Tecnolgicas, Madrid (Spain); Kurtukian, T. [Universite Bordeaux I, CNRS/IN2 P3, CENBG, BP 120, F-33175 Gradignan (France); Nadtochy, P. [Omsk State Univ., Dept. of Theoretical Physics, RU-644077 Omsk (Russian Federation); Schmitt, C. [Grand Accelerateur National D' Ions Lourds, BP 55027, F-14076 Caen Cedex 05 (France); Henzlova, D. [Los Alamos National Laboratory, Safeguards Science and Technology Group N-1, Los Alamos, NM 87545 (United States); Paradela, C. [Group GENP, Dpto. Fisica de Particulas, Universidade de Santiago de Compostela, 15782 Santiago de Compostela (Spain); Bacquias, A. [DSM/IRFU/CEA, 91191 Gif-sur-Ivette (France); Universite Louis Pasteur, Strasbourg (France); Loureiro, D. P. [Group GENP, Dpto. Fisica de Particulas, Universidade de Santiago de Compostela, 15782 Santiago de Compostela (Spain); Foehr, V. [GSI, Planckstrasse 1, 64941, Darmstadt (Germany); Tarrio, D. [Group GENP, Dpto. Fisica de Particulas, Universidade de Santiago de Compostela, 15782 Santiago de Compostela (Spain); Kezzar, K. [DSM/IRFU/CEA, 91191 Gif-sur-Ivette (France)

    2011-07-01

    Total fission cross section induced by protons in {sup 181}Ta and {sup 208}Pb at energies in the range of 300 to 1000 A MeV have been measured at GSI (Germany) using the inverse kinematics technique. A dedicated setup with high efficiency made it possible to determine these cross sections with high accuracy. The new data seed light in the controversial results obtained so far and contribute to the understanding of the fission process at high excitation energies. (authors)

  16. Fission fragment mass and energy distributions as a function of incident neutron energy measured in a lead slowing-down spectrometer

    Science.gov (United States)

    Romano, C.; Danon, Y.; Block, R.; Thompson, J.; Blain, E.; Bond, E.

    2010-01-01

    A new method of measuring fission fragment mass and energy distributions as a function of incident neutron energy in the range from below 0.1 eV to 1 keV has been developed. The method involves placing a double-sided Frisch-gridded fission chamber in Rensselaer Polytechnic Institute’s lead slowing-down spectrometer (LSDS). The high neutron flux of the LSDS allows for the measurement of the energy-dependent, neutron-induced fission cross sections simultaneously with the mass and kinetic energy of the fission fragments of various small samples. The samples may be isotopes that are not available in large quantities (submicrograms) or with small fission cross sections (microbarns). The fission chamber consists of two anodes shielded by Frisch grids on either side of a single cathode. The sample is located in the center of the cathode and is made by depositing small amounts of actinides on very thin films. The chamber was successfully tested and calibrated using 0.41±0.04 ng of Cf252 and the resulting mass distributions were compared to those of previous work. As a proof of concept, the chamber was placed in the LSDS to measure the neutron-induced fission cross section and fragment mass and energy distributions of 25.3±0.5μg of U235. Changes in the mass distributions as a function of incident neutron energy are evident and are examined using the multimodal fission mode model.

  17. Fission fragment mass and energy distributions as a function of incident neutron energy measured in a lead slowing-down spectrometer

    International Nuclear Information System (INIS)

    A new method of measuring fission fragment mass and energy distributions as a function of incident neutron energy in the range from below 0.1 eV to 1 keV has been developed. The method involves placing a double-sided Frisch-gridded fission chamber in Rensselaer Polytechnic Institute's lead slowing-down spectrometer (LSDS). The high neutron flux of the LSDS allows for the measurement of the energy-dependent, neutron-induced fission cross sections simultaneously with the mass and kinetic energy of the fission fragments of various small samples. The samples may be isotopes that are not available in large quantities (submicrograms) or with small fission cross sections (microbarns). The fission chamber consists of two anodes shielded by Frisch grids on either side of a single cathode. The sample is located in the center of the cathode and is made by depositing small amounts of actinides on very thin films. The chamber was successfully tested and calibrated using 0.41±0.04 ng of 252Cf and the resulting mass distributions were compared to those of previous work. As a proof of concept, the chamber was placed in the LSDS to measure the neutron-induced fission cross section and fragment mass and energy distributions of 25.3±0.5 μg of 235U. Changes in the mass distributions as a function of incident neutron energy are evident and are examined using the multimodal fission mode model.

  18. Fission Mass Yield Studies

    International Nuclear Information System (INIS)

    Mass yields from fission induced by a span of neutron energies up to 18 MeV have been measured for Th232, U235 and U238 target nuclei. Particular attention has been given to the dependence of symmetric fission yields on energy. To study the effect of angular momentum, fission yields from the U236 compound nucleus formed by alpha-particle irradiations of Th232 were also studied over the same span of excitation energies. A standard set of Pd109, Ag111, Pd112 and Ag113 symmetric fission yields was generally measured for all irradiations. In addition, yields of Eu156, Cs136 and 2.3-d Cd115 were measured for some selected combinations of projectile, energy and target nucleus. Assays for Zr97 and sometimes also Ba139 served as fission monitors. Altogether 150 fission yields were measured for these combinations of target nucleus, projectile and incident energy. About one-third of these were checked by replicated irradiations. At highest energies for the U236 compound nucleus the symmetric fission yield from alpha-particle-induced fission is about 13% higher than for neutron-induced fission. Dips in symmetric fission yield were observed at the energy onset of third-chance fission for each target and projectile. Some indication of a small central peak in the mass distribution was observed in the yields from U236 compound nucleus fission, but not from the Th233 compound nucleus fission. Detailed mathematical methods have been developed to separate the effects of fissions preceding and following neutron emission. These methods were used to remove the effects of second- and third-chance fissions from the measured symmetric fission yields. These calculated yields for first-chance fission show no dips with energy. The calculations also show that perhaps half the difference between symmetric yields for alpha- particle-induced fission of Th232 and neutron-induced fission of U235 is attributable to angular momentum effects. Both calculated first-chance yields and measured yields

  19. Energies and Yields of Prompt Gamma Rays from Fragments in Slow-Neutron Induced Fission of 235U

    International Nuclear Information System (INIS)

    Measurements were made on the gamma radiation emitted from fission fragments in slow-neutron induced fission of 235U. The fragments were detected with solid state detectors of the surface barrier type and the gamma radiation with a Nal(Tl) scintillator. Mass selection was used so that the gamma radiation could be measured as a function of fragment mass. Time discrimination between the fission gammas and the prompt neutrons released in the fission process was employed to reduce the background. The gamma radiation emitted during different time intervals after the fission event was studied with the help of a collimator, the position of which was changed along the path of the fission fragments. In this way it was possible to select various collimator settings and let gamma radiation of different half-lives be enhanced. Gamma-ray energy spectra from these time components were then recorded as function of mass. The spectrum shape differed greatly depending on the half-life of the radiation and the fragment from which it was emitted. The results of the present measurements were discussed in the light of existing fission models, and comparisons were made with prompt gamma-ray and neutron data from other fission experiments

  20. Measurement of Fission Cross-Sections for Neutrons of Energies in the Range 40-500 keV

    International Nuclear Information System (INIS)

    Measurements have been made of the fission cross-section of U233, U234 , U236, Np237, Pu239 and Pu241 at several neutron energies between 40 keV and 500 keV. Measurements in this energy range are of importance in reactor calculations especially in fast dilute systems where the neutron flux is high in the 10- 100-keV energy range. Recent measurements at this laboratory of the U235 fission cross-section gave absolute values slightly lower than previous data. The present series of measurements are made relative to the new values of the U235 fission cross-section using back-to-back ionization chambers. The fissile foils were assayed by α-assay, direct weighing and coulometry. Good agreement was obtained between these assays. The fission measurements have an estimated accuracy of between 1 % and.2% and,combined with the, error on the U235 fission cross-section,give a final error of about 3% in the fission cross-sections. The present results together with those of previous measurements are given, and the corrections for fission- fragment absorption, backgrounds and scattering are discussed. (author)

  1. Neutron-fragment and Neutron-neutron Correlations in Low-energy Fission

    Science.gov (United States)

    Lestone, J. P.

    2016-01-01

    A computational method has been developed to simulate neutron emission from thermal-neutron induced fission of 235U and from spontaneous fission of 252Cf. Measured pre-emission mass-yield curves, average total kinetic energies and their variances, both as functions of mass split, are used to obtain a representation of the distribution of fragment velocities. Measured average neutron multiplicities as a function of mass split and their dependence on total kinetic energy are used. Simulations can be made to reproduce measured factorial moments of neutron-multiplicity distributions with only minor empirical adjustments to some experimental inputs. The neutron-emission spectra in the rest-frame of the fragments are highly constrained by ENDF/B-VII.1 prompt-fission neutron-spectra evaluations. The n-f correlation measurements of Vorobyev et al. (2010) are consistent with predictions where all neutrons are assumed to be evaporated isotropically from the rest frame of fully accelerated fragments. Measured n-f and n-n correlations of others are a little weaker than the predictions presented here. These weaker correlations could be used to infer a weak scission-neutron source. However, the effect of neutron scattering on the experimental results must be studied in detail before moving away from a null hypothesis that all neutrons are evaporated from the fragments.

  2. Fission cross-section requirements for the nuclear energy programme. Chapter 3

    International Nuclear Information System (INIS)

    A general discussion is given of the use of neutron reaction data in the nuclear energy programme and of the importance of accurate fission cross-section data. A brief summary of the neutron physics of nuclear reactors is followed by a survey of the types of fuel cycle and the fission cross-sections which are of principal interest. The use of nuclear data in reactor calculations is examined and typical target accuracy requirements for the prediction of reactor properties are summarised. Simple arguments are given to show how the accuracy of prediction of some important reactor properties depends on the accuracy of the nuclear data. The use of integral measurements to supplement energy dependent cross-section data is reviewed and a procedure outlined which has been developed for defining a combined programme of integral data and differential cross-section measurements which could meet the chosen target accuracies for a set of reactor parameters. Finally typical fission cross-section accuracy requirements are presented. (U.K.)

  3. Description of the mass and kinetic-energy distributions of fission fragments using an adiabatic potential

    International Nuclear Information System (INIS)

    The mass distributions of fission fragments from rotating composite nuclear systems with parameters Z2/A > 40 have been calculated in the framework of the diffusion model based on the Fokker-Planck equation for the distribution function of the collective variables. In this formalism the two-body nuclear viscosity coefficient describing the intensity of the dissipative forces is the only free parameter. It has been found that the consideration of the angular momenta of the fissile nuclei leads to a small increase in the calculated widths which slightly improves the agreement with the experimental data. In addition, the fission fragment kinetic-energy distributions have been calculated and compared with the measured ones

  4. Cranking and generator-coordinate method description of the fission dynamics at low energies

    International Nuclear Information System (INIS)

    The main aim of the paper is to make the reader more familiar with the generator-coordinate method (GCM), and compare some results given by the cranking and the GCM and GOA (approximation for the overlap of generating function). Also the features of the particle number and the angular momentum projection and the extension of the mean field deformed hamiltonian by the local approximation of the two-body interaction are discussed. The following conclusions can be drawn from carried out investigations. The GCM estimate of the mass parameters is about 1/3 smaller than the cranking one. The mass parameters obtained for the many-body hamiltonians are close to that calculated for the true hamiltonian. The projection onto particle number and a given angular momentum does not affect collectives inertias in the GCM and GOA approximation. The fission barriers have to be corrected by the zero-point energies for the fission and rotational modes only

  5. A Model for Fragment Mass-Versus-Energy Correlations in Fission

    International Nuclear Information System (INIS)

    A detailed investigation of the two-spheioid model of the scission configuration in fission, including the study of both the classical and quantum-mechanical properties of the system, is given. The most probable total fragment kinetic energy as a function of mass division is calculated from minimization of the total potential energy of the system. The root mean square width of the kinetic energy distribution is calculated from the quantum mechanical properties of the system. The local effective stiffness τ as a function of fragment mass m required for these calculations was obtained solely from correlated fragment kinetic energy measurements for thermal-neutron fission of 239Pu, 241Pu, and 235U, together with the minimum potential energy hypothesis. Strong shell effects in the function τ (m) were found to occur in the region of m ≅ 132, where Z ≅ 50, N ≅ 82; however, no shell effects seem to occur in the region of m es 83, where N ≅ 50. We may interpret this result to indicate that for N ≅ 50 proton-deficient nuclei, the ground-state well in the nuclear potential is relatively shallow, so that when these nuclei occur in fission they occur with distorted shapes outside the ground-state well, where the effective stiffness is reduced. Effective stiffnesses obtained for fragments of mass 82 ≤ m ≲ 112 are within ∼ 20% of the liquid-drop-model value. The stiffness parameters τ (m) are used together with minimization of the potential energy to calculate EK (m), the average total fragment kinetic energy as a function of mass. In all cases examined to date, the calculated and experimental energies agree to within about 3%. The root-mean-square width oEK; (m) of the total kinetic energy distribution as a function of fragment mass is determined from quantum-mechanical properties of the system. Normal modes of the system are derived, and a harmonic approximation to the potential is used. Calculated and measured widths agree within about 20% for a wide range

  6. Fission 2009 4. International Workshop on Nuclear Fission and Fission Product Spectroscopy - Compilation of slides

    International Nuclear Information System (INIS)

    This conference is dedicated to the last achievements in experimental and theoretical aspects of the nuclear fission process. The topics include: mass, charge and energy distribution, dynamical aspect of the fission process, nuclear data evaluation, quasi-fission and fission lifetime in super heavy elements, fission fragment spectroscopy, cross-section and fission barrier, and neutron and gamma emission. This document gathers the program of the conference and the slides of the presentations

  7. A model for fragment mass-versus-energy correlations in fission

    International Nuclear Information System (INIS)

    A detailed investigation of the two-spheroid model of the scission configuration in fission, including the study of both the classical and quantum-mechanical properties of the system, is given. The most probable total fragment kinetic energy as a function of mass division is calculated from minimization of the total potential energy of the system. The root mean square width of the kinetic energy distribution is calculated from the quantum mechanical properties of the system. The local effective stiffness τ as a function of fragment mass m required for these calculations was obtained solely from correlated fragment kinetic energy measurements for thermal-neutron fission of 239Pu, 241Pu, and 235U, together with the minimum potential energy hypothesis. Strong shell effects in the function τ (m) were found to occur in the region of m ≅ 132, where Z ≅ 50, N ≅ 82; however, no shell effects seem to occur in the region of m ≅ 83, where N ≅ 50. We may interpret this result to indicate that for N = 50 proton-deficient nuclei, the ground-state well in the nuclear potential is relatively shallow, so that when these nuclei occur in fission they occur with distorted shapes outside the ground-state well, where the effective stiffness is reduced. Effective stiffnesses obtained for fragments of mass 82 ≤ m K (m), the average total fragment kinetic energy as a function of mass. In all cases examined to date, the calculated and experimental energies agree to within about 3%. The root-mean-square width σEK (m) of the total kinetic energy distribution as a function of fragment mass is determined from quantum-mechanical properties of the system. Normal modes of the system are derived, and a harmonic approximation to the potential is used. Calculated and measured widths agree within about 20% for a wide range of fissioning nuclei. Discussions of the sensitivity of these results to the stiffness parameters, to the nuclear vibrational mass parameter, and to nuclear

  8. Complex fission phenomena

    CERN Document Server

    Poenaru, D N; Greiner, W

    2005-01-01

    Complex fission phenomena can be studied in a unified way. Very general reflection asymmetrical equilibrium (saddle-point) nuclear shapes, may be obtained by solving an integro-differential equation without being necessary to specify a certain parametrization. The mass asymmetry in cold fission phenomena can be explained as the result of adding a phenomenological shell correction to the liquid drop model deformation energy. Applications to binary, ternary, and quaternary fission are outlined. Predictions of two alpha accompanied fission are experimentally confirmed.

  9. Measurements of fission product yield in the neutron-induced fission of 238U with average energies of 9.35 MeV and 12.52 MeV

    International Nuclear Information System (INIS)

    The yields of various fission products in the neutron-induced fission of 238U with the flux-weighted averaged neutron energies of 9.35 MeV and 12.52 MeV were determined by using an off-line gamma ray spectroscopic technique. The neutrons were generated using the 7Li(p, n) reaction at Bhabha Atomic Research Centre-Tata Institute of Fundamental Research Pelletron facility, Mumbai. The gamma- ray activities of the fission products were counted in a highly-shielded HPGe detector over a period of several weeks to identify the decaying fission products. At both the neutron energies, the fission-yield values are reported for twelve fission product. The results obtained from the present work have been compared with the similar data for mono-energetic neutrons of comparable energy from the literature and are found to be in good agreement. The peak-to-valley (P/V) ratios were calculated from the fission-yield data and were found to decreases for neutron energy from 9.35 to 12.52 MeV, which indicates the role of excitation energy. The effect of the nuclear structure on the fission product-yield is discussed.

  10. High energy γ emission in the spontaneous fission of 252Cf

    International Nuclear Information System (INIS)

    The prompt γ emission in the spontaneous fission of 252Cf is characterized by an energy spectrum which extends up to 20 MeV. It was established that the spectrum presents in the neighbourhood of symmetric fission an intensity bump in the 3-8 MeV γ energy interval. The origin of this phenomenon is still not well understood, so that it was found interesting to carry out new measurements. The spectrum of the γ rays emitted in spontaneous fission of 252Cf has been measurement in the EUROGAM II multidetector using photovoltaic cells to detect fragments. The aim of the experiment was to investigate the γ yield enhancement which appears for mass fragment ratio near 132/120. This enhancement was found to be composed of two peaks located at 4 MeV and 5.5 MeV respectively. The results obtained confirm the intensity bound in the 3-8 MeV region but this augmentation reaches the maximum when the heavy fragment is near the mass 132. Beyond mass 140 the phenomenon diminish and the γ spectrum regains the behaviour expected for a statistic emission. The additional structure at 5.5 MeV does not vary with excitation energy while the excitation function of the 4 MeV structure is more structured and presents a maximum when the excitation energy is near 8 MeV. It is likely that all or part of this observed phenomenon is due to a particular excitation mode of this isotope associated for instance with a low energy dipole resonance. A theoretical study of this collective effect is under way

  11. 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.

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

    Science.gov (United States)

    Abrecht, David G; Schwantes, Jon M

    2015-03-01

    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. PMID:25675358

  13. Neutronics analysis of water-cooled energy production blanket for a fusion-fission hybrid reactor

    International Nuclear Information System (INIS)

    Neutronics calculations were performed to analyse the parameters of blanket energy multiplication factor (M) and tritium breeding ratio (TBR) in a fusion-fission hybrid reactor for energy production named FDS (Fusion-Driven hybrid System)-EM (Energy Multiplier) blanket. The most significant and main goal of the FDS-EM blanket is to achieve the energy gain of about 1 GWe with self-sustaining tritium, i.e. the M factor is expected to be ∼90. Four different fission materials were taken into account to evaluate M in subcritical blanket: (i) depleted uranium, (ii) natural uranium, (iii) enriched uranium, and (iv) Nuclear Waste (transuranic from 33 000 MWD/MTU PWR (Pressurized Water Reactor) and depleted uranium) oxide. These calculations and analyses were performed using nuclear data library HENDL (Hybrid Evaluated Nuclear Data Library) and a home-developed code VisualBUS. The results showed that the performance of the blanket loaded with Nuclear Waste was most attractive and it could be promising to effectively obtain tritium self-sufficiency and a high-energy multiplication.

  14. The energy dependence of the average number of prompt neutrons resulting from the neutron fission of U236

    International Nuclear Information System (INIS)

    The paper gives the numerical results of measurements of the average number of prompt neutrons per fission, #betta#-barsub(p), from neutron-induced fission of 236U in the 0.8 - 6.0 MeV range. An analysis of corrections and errors is given and a curve is recommended for #betta#-barsub(p) as a function of neutron energy. The estimated measurement accuracy is approximately 1%. (author)

  15. Dependence of Fission-Fragment Properties On Excitation Energy For Neutron-Rich Actinides

    OpenAIRE

    Ramos D; Rodríguez-Tajes C.; Caamaño M.; Farget F.; Audouin L.; Benlliure J.; Casarejos E.; Clement E.; Cortina D.; Delaune O.; Derkx X.; Dijon A.; Doré D.; Fernández-Domínguez B.; France G. de

    2015-01-01

    Experimental access to full isotopic fragment distributions is very important to determine the features of the fission process. However, the isotopic identification of fission fragments has been, in the past, partial and scarce. A solution based on the use of inverse kinematics to study transfer-induced fission of exotic actinides was carried out at GANIL, resulting in the first experiment accessing the full identification of a collection of fissioning systems and their corresponding fission ...

  16. Yield of Prompt Gamma Radiation in Slow-Neutron Induced Fission of 235U a a Function of the Total Fragment Kinetic Energy

    International Nuclear Information System (INIS)

    Fission gamma radiation yields as functions of the total fragment kinetic energy were obtained for 235U thermal-neutron induced fission. The fragments were detected with silicon surface-barrier detectors and the gamma radiation with a Nal(Tl) scintillator. In some of the measurements mass selection was used so that the gamma radiation could also be measured as a function of fragment mass. Time discrimination between the fission gammas and the prompt neutrons released in the fission process was employed to reduce the background. The gamma radiation emitted during different time intervals after the fission event was studied with the help of a collimator, the position of which was changed along the path of the fission fragments. Fission-neutron and gamma-ray data of previous experiments were used for comparisons of the yields, and estimates were made of the variation of the prompt gamma-ray energy with the total fragment kinetic energy

  17. Fragment excitation, kinetic energy distributions and neutron evaporation in nuclear fission calculated from a random excitation model

    International Nuclear Information System (INIS)

    We present a model which allows for the calculation of fragment excitation energy, fragment kinetic energies and neutron evaporation in nuclear fission. The model is based on the assumption that, at the end of the fission process, fragments are excited to a temperature which is proportional to the reaction Q-value. Starting from this assumption the distribution functions of fragment excitation can be formulated and the distribution functions for the kinetic energies can be derived by a Monte Carlo method. From the distribution functions for the excitation energy neutron evaporation characteristics are calculated. (author)

  18. The most compact scission configuration of fragments from low energy fission of 234U and 236U

    International Nuclear Information System (INIS)

    Using a time of flight technique, the maximal values of the kinetic energy as a function of the primary mass of fragments from low energy fission of 234U and 236U were measured by Signarbieux et al. From calculations of scission configurations, one can conclude that, for those two fissioning systems, the maximal values of the total kinetic energy corresponding to fragmentations (42Mo62, 50Sn80) and (42Mo64, 50Sn80) respectively, are equal to the available energy, and that their scission configurations are composed of a spherical heavy fragment and a prolate light fragment, both in their ground state. (author).

  19. Energy-Dependent Boltzmann Equation with Fission and Slowing-Down Kernels

    International Nuclear Information System (INIS)

    This paper presents a study of the energy-dependent neutron transport equation, using Case's method of singular eigenfunctions and considering a continuous energy variable (rather than a multigroup scheme). Both fission and slowing-down kernels are included in the analysis. Under the assumption of simple cross-sections laws, and plane symmetry, a completeness theorem and the Green's function are found for-the infinite medium, for both isotropic and anisotropic scattering, using rather general assumptions as to the slowing-down kernels (including convolution kernels) and, only in the anisotropic case, the generalized Greuling-Goertzel kernel. The crux of the completeness theorem is the inversion and analysis of the spectral properties of a continuous operator which acts upon the energy variable, and depends parametrically upon a complex variable z (with analyticity in some cut complex plane). For half-space problems, the Wiener-Hopf factorization of such an operator is a remarkably difficult problem. However, it can be performed if, for the slowing-down kernel, the Greuling-Goertzel approximation generalized to all its anisotropic components is used, in which case the Wiener-Hopf factorization gives another convolution operator. In this approximation the Milne problem is solved, and a study is made of the extrapolation length. There is a discussion of the difficulties introduced by fission kernels, with emphasis on the coexistence of space-energy separable modes with slowing-down transient modes. (author)

  20. Fission Systems for Mars Exploration

    Science.gov (United States)

    Houts, Michael G.; Kim, T.; Dorney, D. J.; Swint, Marion Shayne

    2012-01-01

    Fission systems are used extensively on earth, and 34 such systems have flown in space. The energy density of fission is over 10 million times that of chemical reactions, giving fission the potential to eliminate energy density constraints for many space missions. Potential safety and operational concerns with fission systems are well understood, and strategies exist for affordably developing such systems. By enabling a power-rich environment and highly efficient propulsion, fission systems could enable affordable, sustainable exploration of Mars.

  1. Integral range, energy, residual range, and linear energy transfer distributions for Californium fission fragments in microelectronics materials

    International Nuclear Information System (INIS)

    This report discusses the advantages and limitations of using Cf-252 radiation sources for single event testing of microelectronics for space environments. Integral distributions for the range, energy, residual range, and linear energy transfer of Cf-252 fission fragments in absorber and microelectronic materials have been calculated. Techniques are suggested for determining when single event testing using Cf-252 is appropriate; also, techniques are given for estimating the saturation cross section and thresh old linear energy transfer from test data. 10 refs., 25 figs., 2 tabs

  2. 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 ...

  3. Nanoscale Advances in Catalysis and Energy Applications

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yimin; Somorjai, Gabor A.

    2010-05-12

    In this perspective, we present an overview of nanoscience applications in catalysis, energy conversion, and energy conservation technologies. We discuss how novel physical and chemical properties of nanomaterials can be applied and engineered to meet the advanced material requirements in the new generation of chemical and energy conversion devices. We highlight some of the latest advances in these nanotechnologies and provide an outlook at the major challenges for further developments.

  4. Measurements of neutron-induced fission cross sections of Pb and Bi at intermediate energies

    International Nuclear Information System (INIS)

    Neutron-induced fission cross sections of natPb and 209Bi have been measured relative to the 238U(n.f) cross section at energies 96 MeV for lead and 133 MeV for bismuth. The measurements were performed at the quasi-mono-energetic neutron beam facility of The Svedberg Laboratory in Uppsala using Frisch-gridded ionization chamber. The results obtained are compared with other experimental data. The present state of the Bi standard recommended by IAEA is discussed. (author)

  5. Neutronic study of an innovative natural uranium–thorium based fusion–fission hybrid energy system

    International Nuclear Information System (INIS)

    Highlights: • An innovative fusion-fission hybrid reactor blanket design is presented. • The blanket adopts seed–blanket concept to improve overall neutron economy. • The blanket is designed with two types of modules, i.e. uranium and thorium module. • The reactor could reach multi operating system purpose. - Abstract: An innovative design for a water cooled fusion–fission hybrid reactor (FFHR), aiming at efficiently utilizing natural uranium and thorium resources, is presented. The major objective is to study the feasibility of this concept balanced with multi-purposes, including energy gain, tritium breeding and 233U breeding. In order to improve overall neutron economy of the system, the fission blanket is designed with two types of modules, i.e. the natural uranium modules (U-modules) and thorium modules (Th-modules), which are alternately arranged in the toroidal and poloidal directions of the blanket. This innovative design is based on a simple intuition of neutron distribution: with the alternate geometrical arrangement, energy multiplication by uranium fission, tritium breeding and 233U breeding are performed separately in different sub-zones in the blanket. The uranium modules which has excellent neutron economy under the combined neutron spectrum, plays the dominant role in the energy production, neutron multiplication and tritium breeding. Excess neutrons produced by the uranium modules are then used to drive the thorium modules (which have poor neutron economy) to breed 233U fuel. Therefore, it creates a new free dimension to realize the blanket’s balanced design. The COUPLE code developed by INET of Tsinghua University is used to simulate the neutronic behavior in the blanket. The simulated results show that with the volumetric ratio of thorium modules about 0.4, the balanced design for multi purposes is achievable, with energy multiplication M ⩾ 9, tritium breeding ratio TBR ⩾ 1.05, and at the end of the five years refueling cycle

  6. Scale and innovation in the energy sector: a focus on photovoltaics and nuclear fission

    Science.gov (United States)

    Trancik, J. E.

    2006-10-01

    Energy technologies have a tendency to become locked in. Mature technologies are favoured due to their accumulated experience and low costs, preventing the entry of new competitors into the market. Public policies support technological evolution in the energy sector through research, development, demonstration and market transformation initiatives. These programmes can reduce CO2 emissions. Their scope, however, is limited by costs and therefore efficiency is critical. Based on a study of photovoltaics and nuclear fission, I show that the scale of an energy technology influences its responsiveness to policy interventions. Rapid innovation can be more effectively supported with limited funds for small scale technologies than for those restricted to the size of a large power plant. An energy infrastructure consisting of small scale technologies may more readily adapt to strict emissions regulations.

  7. 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

  8. Fission and fragmentation of silver and bromine nuclei by 1-6 GeV energy photons

    International Nuclear Information System (INIS)

    Fission and fragmentation of silver and bromine nuclei induced by bremsstrahlung photons in the maximum energy range of 1-6 GeV are studied. A special technique of nuclear emulsion for the highly ionizing nuclear fragment detection is used in the discrimination between nuclear fission and fragmentation events. Films of Ilford-KO nuclear emulsion (approximatelly 1020 atoms/cm2 of Ag, Br) which had been exposed to bremsstrahlung beams in 'Deutsches Elektronen Synchrotron' (DESY, Hamburg) with total doses of approximatelly 1011 equivalent photons are used. Through a detailed analysis of range, angular and angle between fragment distributions, and empirical relations which permit to estimate nuclear fragment energy, range and velocity, the discrimination between fission and fragmentation events is made. Results related to fragment range distribution, angular distribution, distribution of angle between fragments, distribution of ratio between ranges, velocity distributions, forward/backward ratio, fission and fragmentation cross sections, nuclear fissionability and ternary fission frequency are presented and discussed. The results show that the mean photofragmentation cross section in the internal 1-6 GeV (0,09+-0,02mb) is significant when compared to the photofission (0,29+-0,05mb). It is also shown that the mean photofission cross section between 1 and 6 GeV is great by a factor of approximatelly 10 when compared to the foreseen by the cascade-evaporation nuclear model for monoenergetic photons of 0,6 GeV. (L.C.)

  9. Mass Yields and Average Total Kinetic Energy Release in Fission for 235U, 238U, and 239Pu

    Science.gov (United States)

    Duke, Dana

    2015-10-01

    Mass yield distributions and average total kinetic energy (TKE) in neutron induced fission of 235U, 238U, and 239Pu targets were measured with a gridded ionization chamber. Despite decades of fission research, our understanding of how fragment mass yields and TKE depend on incident neutron energy is limited, especially at higher energies (above 5-10 MeV). Improved accuracy in these quantities is important for nuclear technology as it enhances our simulation capabilities and increases the confidence in diagnostic tools. The data can also guide and validate theoretical fission models where the correlation between the fragment mass and TKE is of particular value for constraining models. The Los Alamos Neutron Science Center - Weapons Neutron Research (LANSCE - WNR) provides a neutron beam with energies from thermal to hundreds of MeV, well-suited for filling in the gaps in existing data and exploring fission behavior in the fast neutron region. The results of the studies on target nuclei 235U, 238U, and 239Pu will be presented with a focus on exploring data trends as a function of neutron energy from thermal through 30 MeV. Results indicate clear evidence of structure due to multi-chance fission in the TKE . LA-UR-15-24761.

  10. $\\gamma$-ray energy spectra and multiplicities from the neutron-induced fission of $^{235}$U using STEFF

    CERN Multimedia

    An experiment is proposed to use the STEFF spectrometer at n_TOF to study fragment $\\gamma$-correlations following the neutron-induced fission of $^{235}$U. The STEFF array of 12 NaI detectors will allow measurements of the single $\\gamma$-energy, the $\\gamma$ multiplicity, and the summed $\\gamma$energy distributions as a function of the mass and charge split, and deduced excitation energy in the fission event. These data will be used to study the origin of fission-fragment angular momenta, examining angular distribution eects as a function of incident neutron energy. The principal application of this work is in meeting the NEA high-priority request for improved $\\gamma$ray data from $^{235}$U(n; F). To improve the detection rate and expand the range of detection angles, STEFF will be modied to include two new ssion-fragment detectors each at 45 to the beam direction.

  11. Utilizing fission technology to enable rapid and affordable access to any point in the solar system

    International Nuclear Information System (INIS)

    Fission technology can enable rapid, affordable access to any point in the solar system. Potential fission-based transportation options include bimodal nuclear thermal rockets, high specific energy propulsion systems, and pulsed fission propulsion systems. In-space propellant re-supply enhances the effective performance of all systems, but requires significant infrastructure development. Safe, timely, affordable utilization of first-generation space fission propulsion systems will enable the development of more advanced systems. First generation space systems will build on over 45 years of US and international space fission system technology development to minimize cost

  12. Comparative evaluation of solar, fission, fusion, and fossil energy resources, part 3

    Science.gov (United States)

    Clement, J. D.; Reupke, W. A.

    1974-01-01

    The role of nuclear fission reactors in becoming an important power source in the world is discussed. The supply of fissile nuclear fuel will be severely depleted by the year 2000. With breeder reactors the world supply of uranium could last thousands of years. However, breeder reactors have problems of a large radioactive inventory and an accident potential which could present an unacceptable hazard. Although breeder reactors afford a possible solution to the energy shortage, their ultimate role will depend on demonstrated safety and acceptable risks and environmental effects. Fusion power would also be a long range, essentially permanent, solution to the world's energy problem. Fusion appears to compare favorably with breeders in safety and environmental effects. Research comparing a controlled fusion reactor with the breeder reactor in solving our long range energy needs is discussed.

  13. Fluctuations in Electronic Energy Affecting Singlet Fission Dynamics and Mixing with Charge-Transfer State: Quantum Dynamics Study.

    Science.gov (United States)

    Fujihashi, Yuta; Ishizaki, Akihito

    2016-02-01

    Singlet fission is a spin-allowed process by which a singlet excited state is converted to two triplet states. To understand mechanisms of the ultrafast fission via a charge transfer (CT) state, one has investigated the dynamics through quantum-dynamical calculations with the uncorrelated fluctuation model; however, the electronic states are expected to experience the same fluctuations induced by the surrounding molecules because the electronic structure of the triplet pair state is similar to that of the singlet state except for the spin configuration. Therefore, the fluctuations in the electronic energies could be correlated, and the 1D reaction coordinate model may adequately describe the fission dynamics. In this work we develop a model for describing the fission dynamics to explain the experimentally observed behaviors. We also explore impacts of fluctuations in the energy of the CT state on the fission dynamics and the mixing with the CT state. The overall behavior of the dynamics is insensitive to values of the reorganization energy associated with the transition from the singlet state to the CT state, although the coherent oscillation is affected by the fluctuations. This result indicates that the mixing with the CT state is rather robust under the fluctuations in the energy of the CT state as well as the high-lying CT state. PMID:26732701

  14. Electrolytic extraction of fission noble metals for waste minimizing in advanced actinide separation system

    International Nuclear Information System (INIS)

    Electrochemistry for recovering fission platinum group elements (Pd. Ru) and Re (simulator of Te) from HNO3 solutions, Electrolytic Extraction (EE) method was applied as a basic technology in the new actinides separation process. The deposition yields of these elements increased by the decrease of the initial HNO3, concentration. Co-existence of Pd2+ ion accelerates the deposition of RuNO3- and ReO4- ions, and especially Ru deposition yield was over 99% when Pd2+ ion was added during the electrolysis in 2.SN HNO3 solution. Addition of reducing reagents (hydrazine nitrate and HAN) increased Pd2+ deposition rate, however, these and the other complexing reagents (e.g., oxalic acid and EDTA) decreased the Ru deposition because of preferential Pd2+ deposition as well as those complexation with RuNO3-, respectively. On the electrolytic extraction from the simulated HLLW, the elements which had nobler standard redox potential (E0) tended to show higher deposition yields; the elements which had E0 over 0.7 V (Ru, Te, Se, Rh, Pd) can be quantitatively recovered by 3 hr. electrolysis without dilution of HLLW. (author)

  15. Additional evidence for fusion-fission in 32S+24Mg reactions: Division of excitation energy and spin in the fission fragments

    International Nuclear Information System (INIS)

    We have measured γ rays in coincidence with 12C fragments from the fission of 56Ni produced with the 32S+24Mg reaction at Elab=140 MeV. These data provide insight into the fission process in this light system by giving information about the energy and spin sharing between the 12C and 44Ti fragments, and the spin alignment of the lighter, 12C fragment. The spin transfer and the nuclear ''temperature'' at scission deduced from this measurement can be related to the compound-nucleus spin and potential energy at scission. The results indicate a statistical decay process consistent with the predictions of the transition-state model employing newer estimates of the spin- and mass-asymmetry-dependent saddle-point energies and corresponding shapes. No evidence is found for the spin alignment of the 12C fragments, contrary to what might be expected for a deep-inelastic scattering origin of the fully energy damped yields

  16. Determination of the Spectral Index in the Fission Spectrum Energy Regime

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Amy Sarah [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-16

    Neutron reaction cross sections play a vital role in tracking the production and destruction of isotopes exposed to neutron fluence. They are central to the process of reconciling the initial and final atom inventories. Measurements of irradiated samples by radiochemical methods in tangent with an algorithm are used to evaluate the fluence a sample is exposed to over the course of the irradiation. This algorithm is the Isotope Production Code (IPC) created and used by the radiochemistry data assessment team at Los Alamos National Laboratory (LANL). An integral result is calculated by varying the total neutron fluence seen by a sample. A sample, irradiated in a critical assembly, will be exposed to a unique neutron flux defined by the neutron source and distance of the sample from the source. Neutron cross sections utilized are a function of the hardness of the neutron spectrum at the location of irradiation. A spectral index is used an indicator of the hardness of the neutron spectrum. Cross sections fit forms applied in IPC are collapsed from a LANL 30-group energy structure. Several decades of research and development have been performed to formalize the current IPC cross section library. Basis of the current fission spectrum neutron reaction cross section library is rooted in critical assembly experiments performed from the 1950’s through the early 1970’s at LANL. The focus of this report is development of the spectral index used an indicator of the hardness of the neutron spectrum in the fission spectrum energy regime.

  17. 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 ...

  18. EPRI Asilomar papers: on the possibility of advanced fuel fusion reactors, fusion-fission hybrid breeders, small fusion power reactors, Asilomar, California, December 15--17, 1976

    International Nuclear Information System (INIS)

    An EPRI Ad Hoc Panel met in Asilomar, California for a three day general discussion of topics of particular interest to utility representatives. The three main topics considered were: (1) the possibility of advanced fuel fusion reactors, (2) fusion-fission hybrid breeders, and (3) small fusion power reactors. The report describes the ideas that evolved on these three topics. An example of a ''neutron less'' fusion reactor using the p-11B fuel cycle is described along with the critical questions that need to be addressed. The importance to the utility industry of using fusion neutrons to breed fission fuel for LWRs is outlined and directions for future EPRI research on fusion-fission systems are recommended. The desirability of small fusion power reactors to enable the early commercialization of fusion and for satisfying users' needs is discussed. Areas for possible EPRI research to help achieve this goal are presented

  19. Measurement of the fission cross-section ratio for 237Np/235U around 14 MeV neutron energies

    International Nuclear Information System (INIS)

    Fission cross-section ratio was determined for 237Np/235U around 14 MeV neutron energies with a back-to-back ionization chamber. Neutrons were produced by a 180 KV accelerator using T(d,n)4He reaction. No significant energy dependence was found in the cross section ratio

  20. Requirements and potential development pathways for fission energy supply infrastructures of the 21st century - a systems viewpoint

    International Nuclear Information System (INIS)

    Using an energy supply systems approach, we envision attributes and characteristic needs of a future global fission-based energy supply infrastructure, enumerate potential pathways for meeting those needs, and identify the underlying enabling science and technology developments for R and D efforts to meet the needs

  1. Reaction 48Ca+208Pb: the capture-fission cross-sections and the mass-energy distributions of fragments above and deep below the Coulomb barrier

    OpenAIRE

    Prokhorova, E. V.; Cherepanov, E. A.; Itkis, M.G.; Kondratiev, N. A.; Kozulin, E. M.; Krupa, L.; Oganessian, Yu.Ts.; Pashkevich, V. V.; Pokrovsky, I. V.; Rusanov, A. Ya.

    2003-01-01

    The capture-fission cross-sections in an energy range of 206-242 MeV of 48Ca-projectiles and mass-energy distributions (MEDs) of reaction products in an energy range of 211-242 MeV have been measured in the 48Ca+208Pb reaction using the double-arm time-of-flight spectrometer CORSET. The MEDs of fragments for heated fission were shown to consist of two components. One component, which is due to classical fusion-fission, is associated with the symmetric fission of the 256No compound nucleus. Th...

  2. Investigation of fission like events at energy ≅ 6 MeV/nucleon

    International Nuclear Information System (INIS)

    With a view to study fission followed by complete fusion and fission followed by incomplete fusion, the production cross-sections of about 40 fission like events (137≥A≥65) in 16O + 169Tm system have been measured

  3. Fission products yield in the neutron-induced fission of 232Th using neutrons source from 7Li( p, n)7Be reaction at incident proton energy of 20 MeV

    International Nuclear Information System (INIS)

    This paper presents the measurement of fission product yields from the neutron induced fission of 232Th. These measurements were carried out using the neutron source from 7Li (p,n) reaction at TIFR-BARC Pelletron facility. The yields were obtained using activation and off-line gamma ray spectroscopic technique. The fission yields values are reported for twelve fission products. Activated targets were counted in highly shielded HPGe detectors over a period of several weeks to identify decaying fission products. The results obtained from the present work were compared with the similar data of mono-energetic neutrons of comparable energy from literature and are found to be in good agreement

  4. Fission fragment charge and mass distributions in 239Pu(n ,f ) in the adiabatic nuclear energy density functional theory

    Science.gov (United States)

    Regnier, D.; Dubray, N.; Schunck, N.; Verrière, M.

    2016-05-01

    Background: Accurate knowledge of fission fragment yields is an essential ingredient of numerous applications ranging from the formation of elements in the r process to fuel cycle optimization for nuclear energy. The need for a predictive theory applicable where no data are available, together with the variety of potential applications, is an incentive to develop a fully microscopic approach to fission dynamics. Purpose: In this work, we calculate the pre-neutron emission charge and mass distributions of the fission fragments formed in the neutron-induced fission of 239Pu using a microscopic method based on nuclear density functional theory (DFT). Methods: Our theoretical framework is the nuclear energy density functional (EDF) method, where large-amplitude collective motion is treated adiabatically by using the time-dependent generator coordinate method (TDGCM) under the Gaussian overlap approximation (GOA). In practice, the TDGCM is implemented in two steps. First, a series of constrained EDF calculations map the configuration and potential-energy landscape of the fissioning system for a small set of collective variables (in this work, the axial quadrupole and octupole moments of the nucleus). Then, nuclear dynamics is modeled by propagating a collective wave packet on the potential-energy surface. Fission fragment distributions are extracted from the flux of the collective wave packet through the scission line. Results: We find that the main characteristics of the fission charge and mass distributions can be well reproduced by existing energy functionals even in two-dimensional collective spaces. Theory and experiment agree typically within two mass units for the position of the asymmetric peak. As expected, calculations are sensitive to the structure of the initial state and the prescription for the collective inertia. We emphasize that results are also sensitive to the continuity of the collective landscape near scission. Conclusions: Our analysis confirms

  5. Facility for determination of total kinetic energy and anti ν of spontaneous fission for short living transfermium isotopes

    International Nuclear Information System (INIS)

    To obtain information on the energy of deformation of fission fragments of tpansfermium isotopes in the correlation with prompt neutrons, a binary ionization chamber for the measurement of emission angle of fission fragments relatively to cathode plane, is developed. A range chamber is placed into the ionization chamber having lavsan windows in the 5 mm cathode plane. Two identical chambers with that parallel electrodes have a common cathode, screen grids in front of anode and signal grids in front of screen grids which serve to determine the emission angle of fission fragments. The cathode-signal (first) grid-screen (second) grid-collecting electrode distances are 32.7 and 10 mm, respectively. The grids are made of nichromium wire 100 μm thick, which is wired with the spacing of 1.5 and 1.0 mm for the first and for the second grid respectively. Chamber characteristics are: angle resolution 3-8 deg, energy resolution 1.5%, mass resolution 2-3 a m.u. Results of model experiments are presented. Spectra f 235U, fission fragments, those of distribution of fission fragments in mass and total kinetic energy are measured

  6. Advanced Energy Retrofit Guide Office Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Guopeng; Liu, Bing; Wang, Weimin; Zhang, Jian; Athalye, Rahul A.; Moser, Dave; Crowe, Eliot; Bengtson, Nick; Effinger, Mark; Webster, Lia; Hatten, Mike

    2011-09-27

    The Advanced Energy Retrofit Guide for Office Buildings is a component of the Department of Energy’s Advanced Energy Retrofit Guides for Existing Buildings series. The aim of the guides is to facilitate a rapid escalation in the number of energy efficiency projects in existing buildings and to enhance the quality and depth of those projects. By presenting general project planning guidance as well as financial payback metrics for the most common energy efficiency measures, these guides provide a practical roadmap to effectively planning and implementing performance improvements for existing buildings.

  7. Advanced Energy Retrofit Guide Retail Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Guopeng; Liu, Bing; Zhang, Jian; Wang, Weimin; Athalye, Rahul A.; Moser, Dave; Crowe, Eliot; Bengtson, Nick; Effinger, Mark; Webster, Lia; Hatten, Mike

    2011-09-19

    The Advanced Energy Retrofit Guide for Retail Buildings is a component of the Department of Energy’s Advanced Energy Retrofit Guides for Existing Buildings series. The aim of the guides is to facilitate a rapid escalation in the number of energy efficiency projects in existing buildings and to enhance the quality and depth of those projects. By presenting general project planning guidance as well as financial payback metrics for the most common energy efficiency measures, these guides provide a practical roadmap to effectively planning and implementing performance improvements for existing buildings.

  8. Fission neutron statistical emission

    International Nuclear Information System (INIS)

    The statistical model approach FINESSE (FIssion NEutronS' Statistical Emission) for the description of fission neutron multiplicities, energy spectra and angular distributions is described. Based on an extended Weisskopf ansatz and on a realistic temperature distribution it provides a fragment mass number dependent description of fission neutron data. Model parameters (optical potential, n/γ competition) were fixed on the basis of the 252Cf(sf) (nuclear data standard). Combined with a phenomenological fission model for predicting relevant fragment data as function of asymmetry. FINESSE can be applied to any fission reaction of actinides in the Th-Cf region without further parameter adjustment. Results are presented for 252Cf(sf) and neutron induced fission of 235U, 239Pu, 232Th. Effects of multiple-chance fission are discussed for 232Th(n,xnf) reacation. (author). 46 refs, 11 figs

  9. Center for Advanced Energy Studies Program Plan

    Energy Technology Data Exchange (ETDEWEB)

    Kevin Kostelnik

    2005-09-01

    The world is facing critical energy-related challenges regarding world and national energy demands, advanced science and energy technology delivery, nuclear engineering educational shortfalls, and adequately trained technical staff. Resolution of these issues is important for the United States to ensure a secure and affordable energy supply, which is essential for maintaining U.S. national security, continued economic prosperity, and future sustainable development. One way that the U.S. Department of Energy (DOE) is addressing these challenges is by tasking the Battelle Energy Alliance, LLC (BEA) with developing the Center for Advanced Energy Studies (CAES) at the Idaho National Laboratory (INL). By 2015, CAES will be a self-sustaining, world-class, academic and research institution where the INL; DOE; Idaho, regional, and other national universities; and the international community will cooperate to conduct critical energy-related research, classroom instruction, technical training, policy conceptualization, public dialogue, and other events.

  10. Density Functional Theory Approach to Nuclear Fission

    CERN Document Server

    Schunck, N

    2012-01-01

    The Skyrme nuclear energy density functional theory (DFT) is used to model neutron-induced fission in actinides. This paper focuses on the numerical implementation of the theory. In particular, it reports recent advances in DFT code development on leadership class computers, and presents a detailed analysis of the numerical accuracy of DFT solvers for near-scission calculations.

  11. Nuclear material interrogation via high-energy β-delayed γ rays from fission

    International Nuclear Information System (INIS)

    An increased urgency has been associated with the development of new and improved means for the non-destructive characterization of nuclear waste (or weapon grade materials) that might be hidden in large cargo containers or storage blocks. Passive detection methods based on measurements of neutrons and/or photons are either inapplicable or impractical in many such cases. Active interrogation with neutrons or high-energy photons in a variety of forms currently depends upon the observation of β-delayed neutrons following induced fission to provide a unique signature for fissile material. However, the shielding provided by a thick hydrogenous cargo (or waste container envelope, typically made of concrete) could be so large that this method will fail or will have a very low detection sensitivity. One of the ways to increase this detection sensitivity would be to detect the relatively high intensity of β-delayed γ rays with energies higher than ∼ 2.5 MeV that are emitted from short lived fission products. These β-delayed γ rays have yields that are nearly an order of magnitude higher than the corresponding β-delayed neutrons. In addition, these high energy gammas are likely to be transmitted through the hydrogenous material at least one order of magnitude better than β-delayed neutrons. As a result, the detection sensitivity of nuclear material could be increased by 2 or 3 orders of magnitude. Large area and low resolution plastic scintillators are potential candidates for such a detection system after the cargo is 'scanned' (irradiated) by neutrons or high energy gammas causing fission reactions. In this paper we provide quantitative estimates on the detection limits of fissile material in the case of typical nuclear waste containers surrounded by massive concrete layers with variable contents of hydrogen. Both delayed neutron and delayed gamma interrogation are examined for direct comparison. We show that β-delayed γ rays can offer an increase in

  12. Fuels for Advanced Nuclear Energy Systems

    International Nuclear Information System (INIS)

    Fuels for advanced nuclear reactors differ greatly from conventional light water reactor fuels and vary widely between the different concepts, due differences in reactor architecture and deployment. Functional requirements of all fuel designs include (1) retention of fission products and fuel nuclides, (2) dimensional stability, and (3) maintaining a coolable geometry. In all cases, the anticipated fuel performance under normal or off-normal conditions is the limiting factor in reactor system design, and cumulative effects of increased exposure to higher burnup degrades fuel performance. In high-temperature (thermal) gas reactor systems, fuel particles of uranium dioxide or uranium oxycarbide particles are coated with layers of carbon and SiC (or ZrC). Such fuels have been used successfully to very high burnup (10-20% of heavy-metal atoms) and can withstand transient temperatures up to 1600 C. Oxide (pellet-type) and metal (pin-type) fuels clad in stainless steel tubes have been successfully used in liquid metal cooled fast reactors, attaining burnup of 20% or more of heavy-metal atoms. Those fuel designs are being adapted for actinide management missions, requiring greater contents of minor actinides (e.g. Am, Np, Cm). The current status of each fuel system is reviewed and technical challenges confronting the implementation of each fuel in the context of the entire advanced reactor fuel cycle (fabrication, reactor performance, recycle) are discussed

  13. 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.

  14. Neutron multiplicity for neutron induced fission of 235U, 238U, and 239Pu as a function of neutron energy

    International Nuclear Information System (INIS)

    Recent development in the theory and practice of neutron correlation (''coincidence'') counting require knowledge of the higher factorial moments of the P/sub ν/ distribution (the probability that (ν) neutrons are emitted in a fission) for the case where the fission is induced by bombarding neutrons of more than thermal energies. In contrast to the situation with spontaneous and thermal neutron induced fission, where with a few exceptions the P/sub ν/ is reasonably well known, in the fast neutron energy region, almost no information is available concerning the multiplicity beyond the average value, [ν], even for the most important nuclides. The reason for this is the difficulty of such experiments, with consequent statistically poor and physically inconsistent results

  15. Microscopic description of fission in neutron-rich plutonium isotopes with the Gogny-D1M energy density functional

    International Nuclear Information System (INIS)

    The most recent parametrization D1M of the Gogny energy density functional is used to describe fission in the isotopes 232-280Pu. We resort to the methodology introduced in our previous studies (Phys. Rev. C 88, 054325 (2013) and Phys. Rev. C 89, 054310 (2014)) to compute the fission paths, collective masses and zero point quantum corrections within the Hartree-Fock-Bogoliubov framework. The systematics of the spontaneous fission half-lives tSF, masses and charges of the fragments in plutonium isotopes is analyzed and compared with available experimental data. We also pay attention to isomeric states, the deformation properties of the fragments as well as to the competition between the spontaneous fission and α-decay modes. The impact of pairing correlations on the predicted tSF values is demonstrated with the help of calculations for 232-280Pu, in which the pairing strengths of the Gogny-D1M energy density functional are modified by 5% and 10%, respectively. We further validate the use of the D1M parametrization through the discussion of the half-lives in 242-262Fm. Our calculations corroborate that, though the uncertainties in the absolute values of physical observables are large, the Gogny-D1M Hartree-Fock-Bogoliubov framework still reproduces the trends with mass and/or neutron numbers and therefore represents a reasonable starting point to describe fission in heavy nuclear systems from a microscopic point of view. (orig.)

  16. Energy dependence of the neutron multiplicity P/sub nu/ in fast neutron induced fission of /sup 235,238/U and 239Pu

    International Nuclear Information System (INIS)

    Certain applications require knowledge of the higher moments of the neutron multiplicity probability. It can be shown that the second factorial moment is proportional to the fission rate in the sample, and that the third factorial moment can be of use in disentangling spontaneous fission from induced fission. Using a source of unpublished work in which neutron multiplicities were derived for the fast neutron induced fission of U-235, U-238, and Pu-239, the multiplicity probability has been calculated as a function of neutron energy for the energy range 0 to 10 MeV

  17. Signatures of special nuclear material: High-energy gamma rays following fission

    International Nuclear Information System (INIS)

    Since September 11, 2001, much effort has been devoted to the development of new and improved means for the detection and prevention of the clandestine transport of special nuclear material (SNM, i.e. 235U or 239Pu) and other materials for producing weapons of mass destruction. In a recent Brief Communication, Borozdin et al. showed that cosmic-ray muons could be used to image dense objects inside containers. Here we describe a method for unequivocally identifying SNM in large seagoing containers. Our method is based on the fact that neutron-induced fission of 235U or 239Pu is followed by β decays of short-lived fission fragments during which large numbers of high-energy γ rays (above 3000 keV) are emitted. These γ rays have energies above those of natural γ background, are emitted with significantly greater intensity per fission than β-delayed neutrons, have much higher probabilities of escaping hydrogenous cargo loadings than neutrons, and their energy spectra and time dependencies provide a unique signature of SNM. To demonstrate the main properties of high-energy delayed γ rays, we produced neutrons by bombarding a 1-inch thick water-cooled Be target with 16-MeV deuterons from Lawrence Berkeley National Laboratory's 88-Inch Cyclotron. Neutrons were moderated using steel and polyethylene. We employed a pneumatic transfer system to shuttle targets from the irradiation location inside the polyethylene moderator to a remote shielded counting station. We irradiated 235U (93% isotopic content), 239Pu (95% isotopic content), wood, polyethylene, aluminum, sandstone, and steel targets for 30 seconds (in a thermal-neutron flux of 1.5 x 106/cm2-sec) and acquired 10 sequential γ-ray spectra, each of 3 sec. duration starting 3 sec. after the end of bombardment. We used an 80% relative efficiency coaxial germanium detector and a 30-cm x 30-cm x 10-cm plastic scintillator to detect γ rays and acquired data using ORTEC PC-based electronics and software. The qualitative

  18. Advanced Energy Efficient Roof System

    Energy Technology Data Exchange (ETDEWEB)

    Jane Davidson

    2008-09-30

    Energy consumption in buildings represents 40 percent of primary U.S. energy consumption, split almost equally between residential (22%) and commercial (18%) buildings.1 Space heating (31%) and cooling (12%) account for approximately 9 quadrillion Btu. Improvements in the building envelope can have a significant impact on reducing energy consumption. Thermal losses (or gains) from the roof make up 14 percent of the building component energy load. Infiltration through the building envelope, including the roof, accounts for an additional 28 percent of the heating loads and 16 percent of the cooling loads. These figures provide a strong incentive to develop and implement more energy efficient roof systems. The roof is perhaps the most challenging component of the building envelope to change for many reasons. The engineered roof truss, which has been around since 1956, is relatively low cost and is the industry standard. The roof has multiple functions. A typical wood frame home lasts a long time. Building codes vary across the country. Customer and trade acceptance of new building products and materials may impede market penetration. The energy savings of a new roof system must be balanced with other requirements such as first and life-cycle costs, durability, appearance, and ease of construction. Conventional residential roof construction utilizes closely spaced roof trusses supporting a layer of sheathing and roofing materials. Gypsum board is typically attached to the lower chord of the trusses forming the finished ceiling for the occupied space. Often in warmer climates, the HVAC system and ducts are placed in the unconditioned and otherwise unusable attic. High temperature differentials and leaky ducts result in thermal losses. Penetrations through the ceilings are notoriously difficult to seal and lead to moisture and air infiltration. These issues all contribute to greater energy use and have led builders to consider construction of a conditioned attic. The

  19. Investigation of the prompt neutron emission mechanism in low energy fission of 235,233U(nth, f) and 252Cf(sf)

    OpenAIRE

    Val’ski G.V.; Gagarski A.M.; Shcherbakov O.A.; Vorobyev A.S.; Petrov G.A.

    2010-01-01

    A series of experiments has been performed to measure prompt neutron angular and energy distributions from thermal neutron-induced fission of 235,233U in correlation with the fission fragments. These distributions have been analyzed with the assumption of neutron isotropic emission from accelerated fission fragments. The performed analysis demonstrates that all obtained results can be described within 5% accuracy using this assumption. This discrepancy is approximately constant and doesn’t de...

  20. 50% Advanced Energy Design Guides: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Bonnema, E.; Leach, M.; Pless, S.; Liu, B.; Wang, W.; Thornton, B.; Williams, J.

    2012-07-01

    This paper presents the process, methodology, and assumptions for the development of the 50% Energy Savings Advanced Energy Design Guides (AEDGs), a design guidance document that provides specific recommendations for achieving 50% energy savings above the requirements of ANSI/ASHRAE/IESNA Standard 90.1-2004 in four building types: (1) Small to medium office buildings, (2) K-12 school buildings, (3) Medium to big box retail buildings, (4) Large hospital buildings.

  1. Reevaluation of decay energies of fission product nuclides in JNDC FP Decay Data File

    International Nuclear Information System (INIS)

    The decay data of all experimentally identified fission product nuclides included in the JNDC FP Decay Data File are reviewed in detail, since the missing of beta-transition to unobserved highly excited states in the daughter nucleus is considered to be probable in some cases even for nuclides with small Qβ. Thus the decay energies of 127 nuclides or metastable states except for 88Rb and 143La revised previously are reevaluated. The results of summation calculations based on the revised JNDC FP Decay Data File modified by the present evaluation are in much better agreement with experimentally measured decay power curves than previous ones. Especially, the discrepancy remained for cooling times from a few hundreds to about 1500 seconds is removed. And the agreement is kept within about 5 % for wide range of cooling times. (author)

  2. Coincident measurements of prompt fission γ rays and fission fragments at DANCE

    Science.gov (United States)

    Walker, C. L.; Baramsai, B.; Jandel, M.; Rusev, G.; Couture, A.; Mosby, S.; Ullmann, J.; Kawano, T.; Stetcu, I.; Talou, P.

    2015-10-01

    Modern statistical approaches to modeling fission involve the calculation of not only average quantities but also fully correlated distributions of all fission products. Applications such as those involving the detection of special nuclear materials also rely on fully correlated data of fission products. Experimental measurements of correlated data are thus critical to the validation of theory and the development of important applications. The goal of this experiment was to measure properties of prompt fission gamma-ray emission as a function of fission fragments' total kinetic energy in the spontaneous fission of 252Cf. The measurement was carried out at the Detector for Advanced Neutron Capture Experiments (DANCE), a 4 π γ-ray calorimeter. A prototype design consisting of two silicon detectors was installed in the center of DANCE, allowing simultaneous measurement of fission fragments and γ rays. Effort has been taken to simulate fragment kinetic energy losses as well as γ-ray attenuation in DANCE using such tools as GEANT4 and SRIM. Theoretical predictions generated by the code CGMF were also incorporated as input for these simulations. Results from the experiment and simulations will be presented, along with plans for future measurements.

  3. Complex fission phenomena

    OpenAIRE

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

    2005-01-01

    Complex fission phenomena are studied in a unified way. Very general reflection asymmetrical equilibrium (saddle point) nuclear shapes are obtained by solving an integro-differential equation without being necessary to specify a certain parametrization. The mass asymmetry in binary cold fission of Th and U isotopes is explained as the result of adding a phenomenological shell correction to the liquid drop model deformation energy. Applications to binary, ternary, and quaternary fission are ou...

  4. Advanced Energy Efficient Roof System

    Energy Technology Data Exchange (ETDEWEB)

    Jane Davidson

    2008-09-30

    Energy consumption in buildings represents 40 percent of primary U.S. energy consumption, split almost equally between residential (22%) and commercial (18%) buildings.1 Space heating (31%) and cooling (12%) account for approximately 9 quadrillion Btu. Improvements in the building envelope can have a significant impact on reducing energy consumption. Thermal losses (or gains) from the roof make up 14 percent of the building component energy load. Infiltration through the building envelope, including the roof, accounts for an additional 28 percent of the heating loads and 16 percent of the cooling loads. These figures provide a strong incentive to develop and implement more energy efficient roof systems. The roof is perhaps the most challenging component of the building envelope to change for many reasons. The engineered roof truss, which has been around since 1956, is relatively low cost and is the industry standard. The roof has multiple functions. A typical wood frame home lasts a long time. Building codes vary across the country. Customer and trade acceptance of new building products and materials may impede market penetration. The energy savings of a new roof system must be balanced with other requirements such as first and life-cycle costs, durability, appearance, and ease of construction. Conventional residential roof construction utilizes closely spaced roof trusses supporting a layer of sheathing and roofing materials. Gypsum board is typically attached to the lower chord of the trusses forming the finished ceiling for the occupied space. Often in warmer climates, the HVAC system and ducts are placed in the unconditioned and otherwise unusable attic. High temperature differentials and leaky ducts result in thermal losses. Penetrations through the ceilings are notoriously difficult to seal and lead to moisture and air infiltration. These issues all contribute to greater energy use and have led builders to consider construction of a conditioned attic. The

  5. Measurement of an upper limit of fission energy release in HOLOG using a germanium gamma ray detector

    Energy Technology Data Exchange (ETDEWEB)

    Wang, T.F.

    1998-01-01

    An upper limit of less than 4 mg TNT equivalent fission energy release from the HOLOG experiment was determined using a germanium {gamma}-ray detector to measure the ratio of selected fission-product and plutonium {gamma} rays. Only three hours of {gamma}-ray data collected immediately after the zero-time were analyzed to calculate the above limit. We found no peaks corresponding to the {sup 97} Zr - {sup 97} Nb fission product pair at the gamma-ray energies of E{sub {gamma}} = 743 keV and E{sub {gamma}} = 658 keV, respectively. No information on the plutonium isotopic ratios is revealed because {gamma}-ray peaks in the energy region below 100 keV are not observed due to the high absorption in the containment barrier. The measurement is relatively easy to perform and is not subject to false-positive results because specific fission product and plutonium {gamma} ray energies need to be detected.

  6. Microscopic Description of Induced Fission

    OpenAIRE

    Schunck, N

    2013-01-01

    Selected aspects of the description of neutron-induced fission in 240Pu in the framework of the nuclear energy density functional theory at finite temperature are presented. In particular, we discuss aspects pertaining to the choice of thermodynamic state variables, the evolution of fission barriers as function of the incident neutron energy, and the temperatures of the fission fragments.

  7. Advanced energy projects FY 1992 research summaries

    International Nuclear Information System (INIS)

    The Division of Advanced Energy Projects (AEP) provides support to explore the feasibility of novel, energy-related concepts that evolve from advances in basic research. These concepts are typically at an early stage of scientific definition and, therefore, are beyond the scope of ongoing applied research or technology development programs. The Division provides a mechanism for converting basic research findings to applications that eventually could impact the Nation's energy economy. Technical topics include physical, chemical, materials, engineering, and biotechnologies. Projects can involve interdisciplinary approaches to solve energy-related problems. Projects are supported for a finite period of time, which is typically three years. Annual funding levels for projects are usually about $300,000 but can vary from approximately $50,000 to $500,000. It is expected that, following AEP support, each concept will be sufficiently developed and promising to attract further funding from other sources in order to realize its full potential. There were 39 research projects in the Division of Advanced Energy Projects during Fiscal Year 1992 (October 1, 1991 -- September 30, 1992). The abstracts of those projects are provided to introduce the overall program in Advanced Energy Projects. Further information on a specific project may be obtained by contacting the principal investigator, who is listed below the project title. Projects completed during FY 1992 are indicated

  8. Brownian shape motion on five-dimensional potential-energy surfaces:nuclear fission-fragment mass distributions.

    Science.gov (United States)

    Randrup, Jørgen; Möller, Peter

    2011-04-01

    Although nuclear fission can be understood qualitatively as an evolution of the nuclear shape, a quantitative description has proven to be very elusive. In particular, until now, there existed no model with demonstrated predictive power for the fission-fragment mass yields. Exploiting the expected strongly damped character of nuclear dynamics, we treat the nuclear shape evolution in analogy with Brownian motion and perform random walks on five-dimensional fission potential-energy surfaces which were calculated previously and are the most comprehensive available. Test applications give good reproduction of highly variable experimental mass yields. This novel general approach requires only a single new global parameter, namely, the critical neck size at which the mass split is frozen in, and the results are remarkably insensitive to its specific value. PMID:21517377

  9. Study of the mass, nuclear charge and kinetic energy distribution of the fission fragments produced in the reaction 237 Np (2n th, f)

    International Nuclear Information System (INIS)

    In this work, we report fission fragment mass, energy and charge distributions measured for the fissioning nucleus: 239 Np 146, This odd Z nucleus is formed after double thermal neutron capture on to the 237 Np 144 target nucleus. These measurements were performed at the I.L.L. recoil mass spectrometer ''Lohengrin'' in Grenoble. The fission fragments were registered by an ionisation chamber placed at the focal plane of the spectrometer. The obtained distributions are compared to the 240 Pu 146 fragment mass, energy and charge distributions. They are discussed within the Wilkins' scission-point model. Cold fission has been studied while selecting fragmentations with final kinetic energies close to the maximum energy released in the reaction. These cold fission events are discussed according to a calculation based on the Wilkins' scission-point model extrapolated to the cold fragmentation case. 51 refs

  10. Effect of the energy spectrum and angular momentum of pre-scission neutrons on the prediction of fission fragment angular anisotropy by the models

    Science.gov (United States)

    Soheyli, Saeed; Khanlari, Marzieh Varasteh

    2016-04-01

    Effects of the various neutron emission energy spectra, as well as the influence of the angular momentum of pre-scission neutrons on theoretical predictions of fission fragment angular anisotropies for several heavy-ion induced fission systems are considered. Although theoretical calculations of angular anisotropy are very sensitive to neutron emission correction, the effects of the different values of kinetic energy of emitted neutrons derived from the various neutron emission energy spectra before reaching to the saddle point on the prediction of fission fragment angular distribution by the model are not significant and can be neglected, since these effects on angular anisotropies of fission fragments for a wide range of fissility parameters and excitation energies of compound nuclei are not more than 10%. Furthermore, the theoretical prediction of fission fragment angular anisotropy is not sensitive to the angular momentum of emitted neutrons.

  11. Multiplicity and energy of neutrons from {sup 233}U(n{sub th},f) fission fragments

    Energy Technology Data Exchange (ETDEWEB)

    Nishio, Katsuhisa; Kimura, Itsuro; Nakagome, Yoshihiro [Kyoto Univ. (Japan)

    1998-03-01

    The correlation between fission fragments and prompt neutrons from the reaction {sup 233}U(n{sub th},f) was measured with improved accuracy. The results determined the neutron multiplicity and emission energy as a function of fragment mass and total kinetic energy. The average energy as a function of fragment mass followed a nearly symmetric distribution centered about the equal mass-split and formed a remarkable contrast with the saw-tooth distribution of the average neutron multiplicity. The neutron multiplicity from the specified fragment decreases linearly with total kinetic energy, and the slope of multiplicity with kinetic energy had the minimum value at about 130 u. The level density parameter versus mass determined from the neutron data showed a saw-tooth structure with the pronounced minimum at about 128 and generally followed the formula by Gilbert and Cameron, suggesting that the neutron emission process was very much affected by the shell-effect of the fission fragment. (author)

  12. Compact fission counter for DANCE

    International Nuclear Information System (INIS)

    The Detector for Advanced Neutron Capture Experiments (DANCE) consists of 160 BF2 crystals with equal solid-angle coverage. DANCE is a 4π γ-ray calorimeter and designed to study the neutron-capture reactions on small quantities of radioactive and rare stable nuclei. These reactions are important for the radiochemistry applications and modeling the element production in stars. The recognition of capture event is made by the summed γ-ray energy which is equivalent of the reaction Q-value and unique for a given capture reaction. For a selective group of actinides, where the neutron-induced fission reaction competes favorably with the neutron capture reaction, additional signature is needed to distinguish between fission and capture γ rays for the DANCE measurement. This can be accomplished by introducing a detector system to tag fission fragments and thus establish a unique signature for the fission event. Once this system is implemented, one has the opportunity to study not only the capture but also fission reactions. A parallel-plate avalanche counter (PPAC) has many advantages for the detection of heavy charged particles such as fission fragments. These include fast timing, resistance to radiation damage, and tolerance of high counting rate. A PPAC also can be tuned to be insensitive to α particles, which is important for experiments with α-emitting actinides. Therefore, a PPAC is an ideal detector for experiments requiring a fast and clean trigger for fission. A PPAC with an ingenious design was fabricated in 2006 by integrating amplifiers into the target assembly. However, this counter was proved to be unsuitable for this application because of issues related to the stability of amplifiers and the ability to separate fission fragments from α's. Therefore, a new design is needed. A LLNL proposal to develop a new PPAC for DANCE was funded by NA22 in FY09. The design goal is to minimize the mass for the proposed counter and still be able to maintain a stable

  13. Compact fission counter for DANCE

    Energy Technology Data Exchange (ETDEWEB)

    Wu, C Y; Chyzh, A; Kwan, E; Henderson, R; Gostic, J; Carter, D; Bredeweg, T; Couture, A; Jandel, M; Ullmann, J

    2010-11-06

    The Detector for Advanced Neutron Capture Experiments (DANCE) consists of 160 BF{sub 2} crystals with equal solid-angle coverage. DANCE is a 4{pi} {gamma}-ray calorimeter and designed to study the neutron-capture reactions on small quantities of radioactive and rare stable nuclei. These reactions are important for the radiochemistry applications and modeling the element production in stars. The recognition of capture event is made by the summed {gamma}-ray energy which is equivalent of the reaction Q-value and unique for a given capture reaction. For a selective group of actinides, where the neutron-induced fission reaction competes favorably with the neutron capture reaction, additional signature is needed to distinguish between fission and capture {gamma} rays for the DANCE measurement. This can be accomplished by introducing a detector system to tag fission fragments and thus establish a unique signature for the fission event. Once this system is implemented, one has the opportunity to study not only the capture but also fission reactions. A parallel-plate avalanche counter (PPAC) has many advantages for the detection of heavy charged particles such as fission fragments. These include fast timing, resistance to radiation damage, and tolerance of high counting rate. A PPAC also can be tuned to be insensitive to {alpha} particles, which is important for experiments with {alpha}-emitting actinides. Therefore, a PPAC is an ideal detector for experiments requiring a fast and clean trigger for fission. A PPAC with an ingenious design was fabricated in 2006 by integrating amplifiers into the target assembly. However, this counter was proved to be unsuitable for this application because of issues related to the stability of amplifiers and the ability to separate fission fragments from {alpha}'s. Therefore, a new design is needed. A LLNL proposal to develop a new PPAC for DANCE was funded by NA22 in FY09. The design goal is to minimize the mass for the proposed

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

    International Nuclear Information System (INIS)

    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. - 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 10−3 is achieved for thin high refractive radiators

  15. Advancement of reprocessing technology. The forefront of the actinides/fission products separation

    International Nuclear Information System (INIS)

    The subject which is important for building the future back end process of nuclear fuel is the better compatibility of the sharp rise of economic efficiency with global environmental conditions, taking up the fuel cycle system for fast reactors as the object. Wet reprocessing PUREX process is excellent in its reliability and safety, but from the viewpoint of economic efficiency and the load on waste disposal, same pointing-out has been done. In high level waste liquid, trace minor actinides and large amount of Na salt are the problems. As the advancement of PUREX process, the research on the reduction of Na waste liquid is reported. As for the recent improvement, emphasis has been placed on the control of the behavior of Np, Tc and Pt family. As the wet type actinide separation process, transuranium extraction (TRUEX) process is the relatively new, powerful solvent extraction process. Its development is described. By using the real waste liquid generated by the PUREX test of the spent fuel from fast reactors, the multi-stage, opposite flow extraction test on bench scale has been carried out at the hot cell of Chemical Processing Facility. The separation of actinides using macrocyclic compounds is reported. (K.I.)

  16. Energy Systems Integration: NREL + Advanced Energy (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2015-02-01

    This fact sheet describes the collaboration between NREL and Advanced Energy Industries at the ESIF to test its advanced photovoltaic inverter technology with the ESIF's power hardware-in-the-loop system and megawatt-scale grid simulators.

  17. Uranium and Plutonium Average Prompt-fission Neutron Energy Spectra (PFNS) from the Analysis of NTS NUEX Data

    Science.gov (United States)

    Lestone, J. P.; Shores, E. F.

    2014-05-01

    In neutron experiments (NUEX) conducted at the Nevada Test Site (NTS) by Los Alamos National Laboratory, the time-of-flight of fission-neutrons emitted from nuclear tests were observed by measuring the current generated by the collection of protons scattered from a thin CH2 foil many meters from the nuclear device into a Faraday cup. The time dependence of the Faraday cup current is a measure of the energy spectrum of the neutrons that leak from the device. With good device models and accurate neutron-transport codes, the leakage spectra can be converted into prompt fast-neutron-induced fission-neutron energy spectra. This has been done for two events containing plutonium, and for an earlier event containing uranium. The prompt-fission neutron spectra have been inferred for 1.5-MeV 239Pu(n,f) and 235U(n,f) reactions for outgoing neutron energies from 1.5 to ∼10.5 MeV, in 1-MeV steps. These spectra are in good agreement with the Los Alamos fission model.

  18. Advanced Energy Projects FY 1996 research summaries

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-09-01

    The mission of the Advanced Energy Projects Division (AEP) is to explore the scientific feasibility of novel energy-related concepts. These concepts are typically at an early stage of scientific development and, therefore, are premature for consideration by applied research or technology development programs. The portfolio of projects is dynamic, but reflects the broad role of the Department in supporting research and development for improving the Nation`s energy posture. Topical areas presently receiving support include: alternative energy sources; innovative concepts for energy conversion and storage; alternate pathways to energy efficiency; exploring uses of new scientific discoveries; biologically-based energy concepts; renewable and biodegradable materials; novel materials for energy technology; and innovative approaches to waste treatment and reduction. Summaries of the 70 projects currently being supported are presented. Appendices contain budget information and investigator and institutional indices.

  19. Neutron-induced fission cross sections of 233U and 243Am in the energy range 0.5 Mev En 20 MeV @ n_TOF

    CERN Document Server

    Belloni, F; Milazzo, P M; Calviani, M; Colonna, N; Mastinu, P; Abbondanno, U; Aerts, G; Álvarez, H; Álvarez-Velarde, F; Andriamonje, S; Andrzejewski, J; Assimakopoulos, P; Audouin, L; Badurek, G; Baumann, P; Becvár, F; Berthoumieux, E; Calviño, F; Cano-Ott, D; Capote, R; Carrapiço, C; Cennini, P; Chepel, V; Chiaveri, E; Cortes, G; Couture, A; Cox, J; Dahlfors, M; David, S; Dillmann, I; Domingo-Pardo, C; Dridi, W; Duran, I; Eleftheriadis, C; Embid-Segura, M; Ferrant, L; Ferrari, A; Ferreira-Marques, R; Fujii, K; Furman, W; Goncalves, I; González-Romero, E; Gramegna, F; Guerrero, C; Gunsing, F; Haas, B; Haight, R; Heil, M; Herrera-Martinez, A; Igashira, M; Jericha, E; Käppeler, F; Kadi, Y; Karadimos, D; Karamanis, D; Kerveno, M; Koehler, P; Kossionides, E; Krticka, M; Lampoudis, C; Leeb, H; Lindote, A; Lopes, I; Lozano, M; Lukic, S; Marganiec, J; Marrone, S; Martínez, T; Massimi, C; Mengoni, A; Moreau, C; Mosconi, M; Neves, F; Oberhummer, H; O'Brien, S; Pancin, J; Papachristodoulou, C; Papadopoulos, C; Paradela, C; Patronis, N; Pavlik, A; Pavlopoulos, P; Perrot, L; Pigni, M T; Plag, R; Plompen, A; Plukis, A; Poch, A; Praena, J; Pretel, C; Quesada, J; Rauscher, T; Reifarth, R; Rubbia, C; Rudolf, G; Rullhusen, P; Salgado, J; Santos, C; Sarchiapone, L; Savvidis, I; Stephan, C; Tagliente, G; Tain, J L; Tassan-Got, L; Tavora, L; Terlizzi, R; Vannini, G; Vazl, P; Ventura, A; Villamarin, D; Vincente, M C; Vlachoudis, V; Vlastou, R; Voss, F; Walter, S; Wiescher, M; Wisshak, K

    2011-01-01

    Neutron-induced fission cross-sections of actinides have been recently measured at the neutron time of flight facility n_TOF at CERN in the frame of a research project involving isotopes relevant for nuclear astrophysics and nuclear technologies. Fission fragments are detected by a gas counter with good discrimination between nuclear fission products and background events. Neutron-induced fission cross-sections of 233U and 243Am were determined relative to 235U. The present paper reports the results obtained at neutron energies between 0.5 and 20 MeV.

  20. Fission of intermediate mass nuclei by photons of stopping radiation in the maximum energy range 0,8 - 1,8 MeV

    International Nuclear Information System (INIS)

    The fission of intermediate mass nuclei in Al - Ta interval, induced by stopping radiation phtons of maximum energies between 0,8 and 1.8 GeV is studied. Nd and Sm thin targets and Al, Ti, Co, Zr, Nb, Ag, In and Ta thick targets were used, considering all peculiarities inherent to absorption of fission fragments in the target. The samples were exposed into the 2.5 GeV Electron Synchrotron in Bonn Univerity. The fission fragment tracks were registered in foil type detectors using mica muscovite for Sm and Nd, CR-39 for Al and Ti and makrofol for Co, Zr; Nb, Ag, In, Nd and Ta. The track length and track depth angle distributions were measured for determining fission efficiencies. The fission cross sections and nuclear fissionable of the studied elements were evaluated. (M.C.K.)

  1. Delayed fission

    International Nuclear Information System (INIS)

    Delayed fission is a nuclear process that couples beta decay and fission. In the delayed fission process, a parent nucleus undergoes beta decay or electron capture and thus populates excited states in the daughter nucleus. This review covers experimental methods for detecting and measuring delayed fission. Experimental results (ECDF activities and beta-DF activities) and theory are presented. The future prospects for study of delayed fission are discussed. 50 refs., 8 figs., 2 tabs

  2. ND:GLASS LASER DESIGN FOR LASER ICF FISSION ENERGY (LIFE)

    Energy Technology Data Exchange (ETDEWEB)

    Caird, J A; Agrawal, V; Bayramian, A; Beach, R; Britten, J; Chen, D; Cross, R; Ebbers, C; Erlandson, A; Feit, M; Freitas, B; Ghosh, C; Haefner, C; Homoelle, D; Ladran, T; Latkowski, J; Molander, W; Murray, J; Rubenchik, S; Schaffers, K; Siders, C W; Stappaerts, E; Sutton, S; Telford, S; Trenholme, J; Barty, C J

    2008-10-28

    We have developed preliminary conceptual laser system designs for the Laser ICF (Inertial Confinement Fusion) Fission Energy (LIFE) application. Our approach leverages experience in high-energy Nd:glass laser technology developed for the National Ignition Facility (NIF), along with high-energy-class diode-pumped solid-state laser (HEC-DPSSL) technology developed for the DOE's High Average Power Laser (HAPL) Program and embodied in LLNL's Mercury laser system. We present laser system designs suitable for both indirect-drive, hot spot ignition and indirect-drive, fast ignition targets. Main amplifiers for both systems use laser-diode-pumped Nd:glass slabs oriented at Brewster's angle, as in NIF, but the slabs are much thinner to allow for cooling by high-velocity helium gas as in the Mercury laser system. We also describe a plan to mass-produce pump-diode lasers to bring diode costs down to the order of $0.01 per Watt of peak output power, as needed to make the LIFE application economically attractive.

  3. Decree of 8 October 1969, Stb. 471, concerning the implementation of Sections 13 and 14 of the Nuclear Energy Act (Fissionable Materials and Ores (Registration))

    International Nuclear Information System (INIS)

    This Decree lays down the system for registration and notification of fissionable materials and ores in accordance with the Nuclear Energy Act. The register must list the quantities of fissionable materials and ores available in the Netherlands and their location. This procedure applies only to materials and ores subject to licensing. (NEA)

  4. Book of abstracts of the joint EC-IAEA topical meeting on development of new structural materials for advanced fission and fusion reactor systems

    International Nuclear Information System (INIS)

    Materials performance and reliability are key issues for the safety and competitiveness of future nuclear installations: Generation IV nuclear systems for increased sustainability, advanced systems for non-electrical uses of nuclear energy, partitioning and transmutation systems, as well as thermo-nuclear fusion systems. These systems will have to feature high thermal efficiency and optimized utilization of fuel combined with minimized nuclear waste. For the sustainability of the nuclear option, there is a renewed interest worldwide in new reactor systems, closed fuel cycle research and technology development, and nuclear process heat applications. This requires the development and qualification of new high temperature structural materials with improved radiation and corrosion resistance. To achieve the challenging materials performance parameters, focused research and targeted testing of new candidate materials are necessary. Recent developments regarding new classes of materials with improved microstructural features, such as fibre-reinforced ceramic composite materials, oxide dispersion strengthened steels or advanced ferritic-martensitic steels are promising since they combine good radiation resistance and corrosion properties with high-temperature strength and toughness. In view of a successful and timely implementation of design parameters, in particular for primary circuits, new structural materials have to be qualified during the next decade. To this end an international R and D effort is being undertaken. Recent progress in materials science, supported by computer modelling and advanced materials characterisation techniques, has the potential to accelerate the process of new structural materials development. The scope of the meeting is information exchange and cross-fertilisation of various disciplines, including an overview of recent status of world-wide R and D activities. A comprehensive review of the designs of fission as well as fusion reactor systems

  5. Microscopic description of fission in neutron-rich plutonium isotopes with the Gogny-D1M energy density functional

    CERN Document Server

    Rodriguez-Guzman, R

    2014-01-01

    The most recent parametrization D1M of the Gogny energy density functional is used to describe fission in the isotopes $^{232-280}$ Pu. We resort to the methodology introduced in our previous studies [Phys. Rev. C \\textbf{88}, 054325 (2013) and Phys. Rev. C \\textbf {89}, 054310 (2014)] to compute the fission paths, collective masses and zero point quantum corrections within the Hartree-Fock-Bogoliubov framework. The systematics of the spontaneous fission half-lives t$_{SF}$, masses and charges of the fragments in Plutonium isotopes is analyzed and compared with available experimental data. We also pay attention to isomeric states, the deformation properties of the fragments as well as to the competition between the spontaneous fission and $\\alpha$-decay modes. The impact of pairing correlations on the predicted t$_{SF}$ values is demonstrated with the help of calculations for $^{232-280}$Pu in which the pairing strengths of the Gogny-D1M energy density functional are modified by 5 $\\%$ and 10 $\\%$, respective...

  6. Mass and nuclear charge yields for sup 237 Np(2n sub th ,f) at different fission fragment kinetic energies

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, G.; Barreau, G.; Sicre, A.; Doan, T.P.; Audouard, P.; Leroux, B. (CEA Centre d' Etudes Nucleaires de Bordeaux-Gradignan, 33 - Gradignan (France)); Arafa, W.; Brissot, R.; Bocquet, J.P. (Grenoble-1 Univ., 38 (France). Inst. des Sciences Nucleaires); Faust, H. (Institut Max von Laue - Paul Langevin, 38 - Grenoble (France)); Koczon, P.; Mutterer, M. (Technische Hochschule Darmstadt (Germany, F.R.). Inst. fuer Kernphysik); Goennenwein, F. (Tuebingen Univ. (Germany, F.R.). Physikalisches Inst.); Asghar, M. (Universite des Sciences et de la Technologie Houari Boumediene, Algiers (Algeria). Inst. de Physique); Quade, U.; Rudolph, K. (Muenchen Univ. (Germany, F.R.)); Engelhardt, D. (Karlsruhe Univ. (T.H.) (Germany, F.R.)); Piasecki, E. (Warsaw Univ. (Poland))

    1990-09-03

    The recoil mass separator LOHENGRIN of the Laue-Langevin Institute Grenoble has been used to measure for the first time, the yields of light fission fragments from the fissioning system: {sub 93}{sup 239}Np; this odd-Z nucleus is formed after double thermal neutron capture in a {sub 93}{sup 237}Np target. The mass distributions were measured for different kinetic energies between 92 and 115.5 MeV, but the nuclear charge distributions were determined only up to 112 MeV. These distributions are compared to the distributions obtained for the even-even system {sub 94}{sup 240}Pu. At high kinetic energy, the mass distribution shows a prominent peak around mass number A{sub L}=106. These cold fragmentations are discussed in terms of a calculation based on a scission point model extrapolated to the cold fission case. As expected for an odd-Z fissioning nucleus, the nuclear charge distributions do not reveal any odd-even effect. The global neutron odd-even effect is found to be (8.1{plus minus}1.5)%. A simple model has been used to show that most of the neutron odd-even effect results from prompt neutron evaporation from the fragments. (orig.).

  7. Measurements of high-energy neutron-induced fission ofnatPb and 209Bi

    Directory of Open Access Journals (Sweden)

    Couture A.

    2010-10-01

    Full Text Available The CERN Neutron Time-Of-Flight (n_TOF facility is well suited to measure low cross sections as those of neutron-induced fission in subactinides. The cross section ratios of natPb and 209Bi relative to 235U and 238U were measured using PPAC detectors and a fragment coincidence method that allows us to identify the fission events. The present experiment provides first results for neutron-induced fission up to 1 GeV. Good agreement is found with previous experimental data below 200 MeV. The comparison with proton-induced fission indicates that the limiting regime where neutron-induced and proton-induced fission reach equal cross sections is close to 1 GeV.

  8. High-energy Neutron-induced Fission Cross Sections of Natural Lead and Bismuth-209

    CERN Document Server

    Tarrio, D; Carrapico, C; Eleftheriadis, C; Leeb, H; Calvino, F; Herrera-Martinez, A; Savvidis, I; Vlachoudis, V; Haas, B; Koehler, P; Vannini, G; Oshima, M; Le Naour, C; Gramegna, F; Wiescher, M; Pigni, M T; Audouin, L; Mengoni, A; Quesada, J; Becvar, F; Plag, R; Cennini, P; Mosconi, M; Rauscher, T; Couture, A; Capote, R; Sarchiapone, L; Vlastou, R; Domingo-Pardo, C; Dillmann, I; Pavlopoulos, P; Karamanis, D; Krticka, M; Jericha, E; Ferrari, A; Martinez, T; Trubert, D; Oberhummer, H; Karadimos, D; Plompen, A; Isaev, S; Terlizzi, R; Cortes, G; Cox, J; Cano-Ott, D; Pretel, C; Colonna, N; Berthoumieux, E; Vaz, P; Heil, M; Lopes, I; Lampoudis, C; Walter, S; Calviani, M; Gonzalez-Romero, E; Embid-Segura, M; Stephan, C; Igashira, M; Papachristodoulou, C; Aerts, G; Tavora, L; Berthier, B; Rudolf, G; Andrzejewski, J; Villamarin, D; Ferreira-Marques, R; Tain, J L; O'Brien, S; Reifarth, R; Kadi, Y; Neves, F; Poch, A; Kerveno, M; Rubbia, C; Lazano, M; Dahlfors, M; Wisshak, K; Salgado, J; Dridi, W; Ventura, A; Andriamonje, S; Assimakopoulos, P; Santos, C; Voss, F; Ferrant, L; Patronis, N; Chiaveri, E; Guerrero, C; Perrot, L; Vicente, M C; Lindote, A; Praena, J; Baumann, P; Kappeler, F; Rullhusen, P; Furman, W; David, S; Marrone, S; Tassan-Got, L; Gunsig, F; Alvarez-Velarde, F; Massimi, C; Mastinu, P; Pancin, J; Papadopoulos, C; Tagliente, G; Haight, R; Chepel, V; Kossionides, E; Badurek, G; Marganiec, J; Lukic, S; Pavlik, A; Goncalves, I; Duran, I; Alvarez, H; Abbondanno, U; Fujii, K; Milazzo, P M; Moreau, C

    2011-01-01

    The CERN Neutron Time-Of-Flight (n\\_TOF) facility is well suited to measure small neutron-induced fission cross sections, as those of subactinides. The cross section ratios of (nat)Pb and (209)Bi relative to (235)U and (238)U were measured using PPAC detectors. The fragment coincidence method allows to unambiguously identify the fission events. The present experiment provides the first results for neutron-induced fission up to 1 GeV for (nat)Pb and (209)Bi. A good agreement with previous experimental data below 200 MeV is shown. The comparison with proton-induced fission indicates that the limiting regime where neutron-induced and proton-induced fission reach equal cross section is close to 1 GeV.

  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. Fission Yields and Other Diagnostics for Nuclear Performance

    International Nuclear Information System (INIS)

    I summarize advances in our understanding of basic nuclear physics cross sections and decay properties that are needed to characterize the magnitude and energy-dependence of a neutron flux, and to determine the amount of fission burnup in plutonium fuel. The number of fissions that have occurred in a neutron environment can be deduced from measurements of the fission products created, providing that the fission product yields are known accurately. I describe how our understanding of plutonium fission product yields has improved in recent years through a meta-analysis of various measured data, and through identification of fission product yield incident-energy dependencies over the 0.2-2 MeV fast energy region. This led to the resolution of a previous discrepancy between the Los Alamos and Lawrence Livermore National Laboratories in their plutonium yield assessments in the fast energy region, although more experimental work is still needed to resolve discrepancies at 14 MeV. Work is also described that has improved our understanding of (n,2n) cross sections that are used as diagnostics of the high-energy neutron spectrum – both on plutonium and americium, and on the radiochemical detectors yttrium, iridium, and thulium. Finally, some observations are made on the importance of continuing to develop our Evaluated Nuclear Data Files (ENDF) database using physics insights from differential cross section and integral laboratory experiments and from nuclear theory advances

  11. 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.

  12. Atomic energy to advance human progress

    International Nuclear Information System (INIS)

    Dr Manmohan Singh, the prime minister of India on the occasion of the inaugural ceremony of international conference on peaceful uses of atomic energy said that the return of India to the international nuclear global main streams is of high significance not only for India but for global energy security as well. It is not beyond the imagination of the human mind to devise solutions and strategies that exploit the vast potential of atomic energy to advance human progress, while assuring global peace and security

  13. Electrospinning for advanced energy and environmental applications

    CERN Document Server

    Cavaliere, Sara

    2015-01-01

    Electrospinning for Advanced Energy and Environmental Applications delivers a state-of-the-art overview of the use of electrospun fibers in energy conversion and storage, as well as in environmental sensing and remediation. Featuring contributions from leading experts in electrospinning and its specific applications, this book: Introduces the electrospinning technique and its origins, outlining achievable one-dimensional (1D) nanoscaled materials and their various applicationsDiscusses the use of electrospun materials in energy devices, including low- and high-temperature fuel cells, hydrogen

  14. Microscopic description of fission in neutron-rich plutonium isotopes with the Gogny-D1M energy density functional

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Guzman, R. [Rice University, Department of Physics and Astronomy, Houston, Texas (United States); Rice University, Department of Chemistry, Houston, Texas (United States); Robledo, L.M. [Universidad Autonoma de Madrid, Departamento de Fisica Teorica, Madrid (Spain)

    2014-09-15

    The most recent parametrization D1M of the Gogny energy density functional is used to describe fission in the isotopes {sup 232-280}Pu. We resort to the methodology introduced in our previous studies (Phys. Rev. C 88, 054325 (2013) and Phys. Rev. C 89, 054310 (2014)) to compute the fission paths, collective masses and zero point quantum corrections within the Hartree-Fock-Bogoliubov framework. The systematics of the spontaneous fission half-lives t{sub SF}, masses and charges of the fragments in plutonium isotopes is analyzed and compared with available experimental data. We also pay attention to isomeric states, the deformation properties of the fragments as well as to the competition between the spontaneous fission and α-decay modes. The impact of pairing correlations on the predicted t{sub SF} values is demonstrated with the help of calculations for {sup 232-280}Pu, in which the pairing strengths of the Gogny-D1M energy density functional are modified by 5% and 10%, respectively. We further validate the use of the D1M parametrization through the discussion of the half-lives in {sup 242-262}Fm. Our calculations corroborate that, though the uncertainties in the absolute values of physical observables are large, the Gogny-D1M Hartree-Fock-Bogoliubov framework still reproduces the trends with mass and/or neutron numbers and therefore represents a reasonable starting point to describe fission in heavy nuclear systems from a microscopic point of view. (orig.)

  15. Mass-energy distribution of fragments in Langevin dynamics of fission induced by heavy ions

    Directory of Open Access Journals (Sweden)

    Vanin D. V.

    2012-12-01

    Full Text Available Four-dimensional Langevin equation was employed to calculate mass-energy distributions of fission fragments of highly excited compound nuclei. The research took into account not only three shape collective coordinates introduced on the basis of {c,h,α}-parametrization but also orientation degree of freedom (K-state— spin about the symmetry axis. Overdamped Langevin equation was used to describe the evolution of the K-state. Friction tensor was calculated using the “wall+window” model of the modified one-body dissipation mechanism with a reduction coeffcient from the “wall” formula ks. The calculations have been performed with ks = 0:25 and ks = 1:0. To learn more about the role of the dissipation effects the calculations have also been done with use of the chaoticity measure of nucleon movements in the nuclear shape configuration as ks parameter. Calculations were performed for the large number of compound nuclei with Z2/A parameter in the range 21 ≤ Z2/A ≤ 44. The goal was to study the mass-energy distributions not only for heavy nuclei but also for light nuclei close to the Businaro-Gallone point. Mass-energy distributions and variances of the mass fragments are well reproduced in the applied calculations for all considered compound nuclei. It was shown that inclusion of the K-state in the dynamical model produces considerable increase of the mass and energy variances. Inclusion of the chaoticity measure to the friction tensor provides a better agreement with the experiment results on mass variances.

  16. Sustainable and safe nuclear fission energy technology and safety of fast and thermal nuclear reactors

    CERN Document Server

    Kessler, Günter

    2012-01-01

    Unlike existing books of nuclear reactor physics, nuclear engineering and nuclear chemical engineering this book covers a complete description and evaluation of nuclear fission power generation. It covers the whole nuclear fuel cycle, from the extraction of natural uranium from ore mines, uranium conversion and enrichment up to the fabrication of fuel elements for the cores of various types of fission reactors. This is followed by the description of the different fuel cycle options and the final storage in nuclear waste repositories. In addition the release of radioactivity under normal and possible accidental conditions is given for all parts of the nuclear fuel cycle and especially for the different fission reactor types.

  17. Detecting special nuclear materials in containers using high-energy gamma rays emitted by fission products

    Science.gov (United States)

    Norman, Eric B.; Prussin, Stanley G.

    2007-10-02

    A method and a system for detecting the presence of special nuclear materials in a container. The system and its method include irradiating the container with an energetic beam, so as to induce a fission in the special nuclear materials, detecting the gamma rays that are emitted from the fission products formed by the fission, to produce a detector signal, comparing the detector signal with a threshold value to form a comparison, and detecting the presence of the special nuclear materials using the comparison.

  18. Advanced Low Energy Adaptive Clustering Hierarchy

    Directory of Open Access Journals (Sweden)

    Ezzati Abdellah,

    2010-10-01

    Full Text Available The use of Wireless Sensor Networks (WSNs is anticipated to bring enormous changes in data gathering, processing and dissemination for different environments and applications. However, a WSN is a power constrained system, since nodes run on limited power batteries which shorten its lifespan. Prolonging the network lifetime depends on efficient management of sensing node energy resource. Hierarchicalrouting protocols are best known in regard to energy efficiency. By using a clustering technique hierarchical routing protocols greatly minimize energy consumed in collecting and disseminating data. Low Energy Adaptive Clustering Hierarchy (LEACH is one of the undamental protocols in this class. In this paper we propose Advanced LEACH (A-LEACH, a heterogeneous-energy protocol to decrease probability of failure nodes and to prolong the time interval before the death of the first node (we refer to as stability period and increasing the lifetime in heterogeneous WSNs, which is crucial for many applications.

  19. Comparative evaluation of solar, fission, fusion, and fossil energy resources. Part 1: Solar energy

    Science.gov (United States)

    Williams, J. R.

    1974-01-01

    The utilization of solar energy to meet the energy needs of the U.S. is discussed. Topics discussed include: availability of solar energy, solar energy collectors, heating for houses and buildings, solar water heater, electric power generation, and ocean thermal power.

  20. Communicating about advanced nuclear energy plants

    International Nuclear Information System (INIS)

    The success of advanced nuclear energy plants, as with any new product, will not depend on design alone. Success will require public support and good communications to achieve that support. In the past, communication weaknesses - including mixed and confusing messages - have sometimes created barriers between the technical community and the public. Several lessons learned from a decade of social science research in the United States of America have implications for communicating effectively about advanced design nuclear energy plants: (1) Most audiences are open-minded and receptive to communications on this topic. They view nuclear energy as a fuel of the future and want to be comfortable about the future. Most people in the USA (82%) expect future nuclear energy plants to be safer, so the improvements being made are simply consistent with public expectations. (2) Few people pay close attention to energy issues. (3) Communications must be simple and free of jargon. Because people do not pay close attention to the issues, their knowledge is limited. Some terms used by the industry to describe advanced design plants are misinterpreted. (4) Good communications focus on consumer wants and values, not industry needs or problems. People care about generational responsibility, planning for the future, environmental protection and security. (5) Benefits and safeguards should be shown instead of risk comparisons. Generic benefits of nuclear energy, such as clean air, are important to consumers. (6) Pictures and hand-on demonstrations help in communicating about nuclear energy plants, because many of the discussion concepts are abstract. (7) Trust is crucial and is established now for tomorrow through word and deed. (author)

  1. Measurements of neutron cross sections for advanced nuclear energy systems at n_TOF (CERN

    Directory of Open Access Journals (Sweden)

    Barbagallo M.

    2014-03-01

    Full Text Available The n_TOF facility operates at CERN with the aim of addressing the request of high accuracy nuclear data for advanced nuclear energy systems as well as for nuclear astrophysics. Thanks to the features of the neutron beam, important results have been obtained on neutron induced fission and capture cross sections of U, Pu and minor actinides. Recently the construction of another beam line has started; the new line will be complementary to the first one, allowing to further extend the experimental program foreseen for next measurement campaigns.

  2. Measurement of Fragment Mass Distributions in Neutron-induced Fission of 238U and 232Th at Intermediate Energies

    International Nuclear Information System (INIS)

    Conceptual analysis of accelerator-driven systems assumes extensive use of nuclear data on neutron-induced reactions at intermediate energies. In particular, information about the fission fragment yields from the 238U(n,f) and 232Th(n,f) reactions is of particular interest at neutron energies from 10 to 200 MeV. However, there is a lack of such data for both 238U and 232Th. Up to now, the intermediate energy measurements have been performed for 238U only, and there are no data for the 232Th(n,f) reaction. The aim of the work is to provide such data. Fission fragment mass distributions for the 232Th(n,f) and 238U(n,f) reactions have been measured for the incident neutron energies 32.8 MeV, 45.3 MeV and 59.9 MeV. The experiments have been performed at the neutron beam facility of the Universite Catholique de Louvain, Belgium. A multi-section Frisch-gridded ionization chamber has been used as a fission fragment detector. The data obtained have been interpreted in terms of the multimodal random neck-rupture model (MMRNRM). (authors)

  3. Advanced energy projects FY 1994 research summaries

    Energy Technology Data Exchange (ETDEWEB)

    1994-09-01

    The Division of Advanced Energy Projects (AEP) provides support to explore the feasibility of novel, energy-related concepts that evolve from advances in basic research. These concepts are typically at an early stage of scientific definition and, therefore, are premature for consideration by applied research or technology development programs. The AEP also supports high-risk, exploratory concepts that do not readily fit into a program area but could have several applications that may span scientific disciplines or technical areas. Projects supported by the Division arise from unsolicited ideas and concepts submitted by researchers. The portfolio of projects is dynamic and reflects the broad role of the Department in supporting research and development for improving the Nation`s energy outlook. FY 1994 projects include the following topical areas: novel materials for energy technology; renewable and biodegradable materials; exploring uses of new scientific discoveries; alternate pathways to energy efficiency; alternative energy sources; and innovative approaches to waste treatment and reduction. Summaries are given for 66 projects.

  4. Advanced energy projects FY 1994 research summaries

    International Nuclear Information System (INIS)

    The Division of Advanced Energy Projects (AEP) provides support to explore the feasibility of novel, energy-related concepts that evolve from advances in basic research. These concepts are typically at an early stage of scientific definition and, therefore, are premature for consideration by applied research or technology development programs. The AEP also supports high-risk, exploratory concepts that do not readily fit into a program area but could have several applications that may span scientific disciplines or technical areas. Projects supported by the Division arise from unsolicited ideas and concepts submitted by researchers. The portfolio of projects is dynamic and reflects the broad role of the Department in supporting research and development for improving the Nation's energy outlook. FY 1994 projects include the following topical areas: novel materials for energy technology; renewable and biodegradable materials; exploring uses of new scientific discoveries; alternate pathways to energy efficiency; alternative energy sources; and innovative approaches to waste treatment and reduction. Summaries are given for 66 projects

  5. Nuclear fission

    International Nuclear Information System (INIS)

    The nuclear fission process is pedagogically reviewed from a macroscopic-microscopic point of view. The Droplet model is considered. The fission dynamics is discussed utilizing path integrals and semiclassical methods. (L.C.)

  6. Measurement of Neutron Induced and Spontaneous Fission in Pu-242 at DANCE

    Science.gov (United States)

    Chyzh, Andrii; Wu, C. Y.; Henderson, R.; Couture, A.; Lee, H. Y.; Ullmann, J.; O'Donnell, J. M.; Jandel, M.; Haight, R. C.; Bredeweg, T. A.; Dance Collaboration

    2013-10-01

    Neutron capture and fission reactions are important in nuclear engineering and physics. DANCE (Detector for Advanced Neutron Capture Measurement, LANL) combined with PPAC (avalanche technique based fission tagging detector, LLNL) were used to study neutron induced and spontaneous fission in 242Pu. 2 measurements were performed in 2013. The first experiment was done without the incident neutron beam with the fission tagging ability to study γ-rays emitted in the spontaneous fission of 242Pu. The second one - with the neutron beam to measure both the neutron capture and fission reactions. This is the first direct measurement of prompt fission γ-rays in 242Pu. The γ-ray multiplicity, γ-ray energy, and total energy of γ-rays per fission in 242Pu will be presented. These distributions of the 242Pu spontaneous fission will be compared to those in the 241Pu neutron induced fission. This work was performed under the auspices of the US Department of Energy by Los Alamos National Laboratory under Contract DE-AC52-06NA25396 and Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  7. Advanced energy projects: FY 1987 research summaries

    International Nuclear Information System (INIS)

    This report contains brief summaries of all projects active in the Division of Advanced Energy Projects during Fiscal Year 1987 (October 1, 1986-September 30, 1987). The intent of this compilation is to provide a convenient means for quickly acquainting an interested reader with the program in Advanced Energy Projects. More detailed information on research activities in a particular project may be obtained by contacting directly the principal investigator. Some projects will have reached the end of their contract periods by the time this book appears, and will, therefore, no longer be active. Those cases in which work was completed in FY '87 are indicated by the footnote: Project completed. The annual funding level of each project is shown

  8. Advances in energy and environment. Vol. 1: Energy

    International Nuclear Information System (INIS)

    The 5th conference of energy and environment was held on 3-6 June 1996 in Cairo. The specialists discussed the effects of advances in energy and environment. The applications of solar energy, heat transfer, thermal application, storage and bio-conversion, fuels, energy and development. Studies were discussed at the meeting and more than 1000 papers were presented. This first volume covers papers presented on the following topics: solar thermal, heat transfer and thermal applications, storage and bio-conversion, refrigeration and iar conditioning, combustion, fuels and engines, energy and development. tabs., figs

  9. Interpretation of the low energy fission process in the framework of dinuclear system conception

    Science.gov (United States)

    Volkov, V. V.; Kalandarov, Sh. A.

    2016-03-01

    The possibility of the interpretation of fission of heavy nuclei as the process of formation, evolution and decay of dinuclear system is discussed. The interpretation is based on the nuclear interaction data obtained in heavy-ion nuclear physics investigations.

  10. Radiolysis in aqueous solution of dinucleoside monophosphates by high-energy electrons and fission neutrons.

    Science.gov (United States)

    Vaishnav, Y N; Swenberg, C E

    1993-01-01

    The radiation chemistry in aqueous solution of the dinucleoside monophosphate d-[CpT] and its sequence isomer d-[TpC] in air or nitrogen was examined using different qualities and quantities of radiations. High-performance liquid chromatography and gas chromatography-mass spectrometry were used to analyze the high-energy electron (13.2 MeV) exposure products or fission-neutron exposure products of d-[CpT] and d-[TpC]. A comparison of product profiles obtained from irradiated d-[CpT] and d-[TpC] suggests that, at relatively low radiation doses (50-250 Gy), products are formed by N-glycosidic or phosphodiester bond-cleavage, while at higher doses (500-1000 Gy) additional products were detected as a consequence of ring-modification mechanisms. The plots of radiation dose-yield and corresponding calculated G values of the released undamaged bases and nucleosides from d-[CpT] and d-[TpC] suggest a base-sequence dependence and a quality- and quantity-dependent response to ionizing radiation. Although the product quantities formed from sequence isomers were slightly different, we found no qualitative differences in the product formed at the lowest doses examined. PMID:8434108

  11. Fission of transactinide elements described in terms of generalized Cassinian ovals: Fragment mass and total kinetic energy distributions

    Science.gov (United States)

    Carjan, N.; Ivanyuk, F. A.; Oganessian, Yu.; Ter-Akopian, G.

    2015-10-01

    The total deformation energy at scission for Z = 100, 102, 104 and 106 isotopes is calculated using the Strutinsky's procedure and nuclear shapes described in terms of Cassinian ovals generalized by the inclusion of three additional shape parameters: α1, α4 and α6. The corresponding fragment-mass distributions are estimated supposing they are due to thermal fluctuations in the mass asymmetry degree of freedom. For these four series of isotopes the experimentally observed transition from asymmetric to symmetric fission, that happens with increasing mass number A, is qualitatively reproduced. In lighter isotopes (e.g. 254Fm and 254Rf) two mass-asymmetric fission modes are predicted to occur with comparable yields: one having relatively compact and the other relatively elongated scission configurations. On the other hand, in heavier isotopes (e.g. 264Fm and 264Rf) the fragment-mass distributions are predicted to be narrow single-peaked around A / 2 corresponding to essentially one mass-symmetric fission mode. The mass distributions are estimated separately for each fission mode, in the case of Fm and Rf isotopes, in order to display their inversion when A increases. Finally the distributions of the total kinetic energy of the fragments are calculated, for the same isotopes, in the point-charge approximation. Non-Gaussian shapes are obtained. With increasing mass number A, a transition from a distribution tailing towards higher energies to a distribution tailing towards lower energies and an increase of the difference in the peak positions of the two modes were observed; again in qualitative agreement with experimental data.

  12. Small Scale Indigenous Molybdenum-99 Production Using LEU Fission at Chilean Nuclear Energy Commission [Country report: Chile

    International Nuclear Information System (INIS)

    This report contains the results of the activities carried out in the Chilean Nuclear Energy Commission (CCHEN) under CRP Nº 13358 “Small Scale Indigenous Molybdenum-99 Production Using LEU Fission” started in October 2005 to November 2011. The object of the project was to develop the basic infrastructure and to establish the conditions to obtain fission molybdenum-99 (99Mo) by neutron irradiation of uranium-235 (235U) targets in RECH-1 reactor located in Santiago, Chile

  13. Sustainable and safe nuclear fission energy. Technology and safety of fast and thermal nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Kessler, Guenter

    2012-07-01

    Written by one of the world-leading specialists in reactor physics and safety Most comprehensive book on nuclear fission technology, new safety concepts and waste disposal Complete description and evaluation of nuclear fission power generation Covers the whole nuclear fuel cycle, from the extraction of natural uranium, uranium conversion and enrichment up to the fabrication of fuel elements Description of the different fuel cycle options Presents viable solutions for safe and long-term storage of nuclear waste Recently developed new safety concepts for fission reactors Unlike existing books of nuclear reactor physics, nuclear engineering and nuclear chemical engineering this book covers a complete description and evaluation of nuclear fission power generation. It covers the whole nuclear fuel cycle, from the extraction of natural uranium from ore mines, uranium conversion and enrichment up to the fabrication of fuel elements for the cores of various types of fission reactors. This is followed by the description of the different fuel cycle options and the final storage in nuclear waste repositories. In addition the release of radioactivity under normal and possible accidental conditions is given for all parts of the nuclear fuel cycle and especially for the different fission reactor types.

  14. Comment on "Fission Mass Widths in $^{19}$F + $^{232}$Th, $^{16}$O + $^{235,238}$ U reactions at near barrier energies

    OpenAIRE

    Ghosh, T.K.; Bhattacharya, P

    2005-01-01

    A critical re-analysis of the experimental data to reject transfer fission component did not change the fragment mass widths and hence the conclusion regarding abrupt rise in mass widths with decreasing energy around Coulomb barrier remains unchanged

  15. Variation of the Binary-to-Ternary Fission Ratio for U235 in the Thermal-Neutron-Energy Region

    International Nuclear Information System (INIS)

    The slow chopper installed at BRI was used to make an accurate determination of the binary-to-ternary fission ratio for U235 in the neutron-energy range from 0.005 eV to 0.2 eV. Large gold-silicon suríace-barrier detectors are used for the consecutive measurement of long-range α-particles (absorber in) and fission fragments (absorber out). The time analysis is done with a 100-channel time-of-flight analyser. A one-metre flight-path and a rotor speed of 50 rev/s is used. The B/T ratio was also measured with a high statistical accuracy (about 1%) in intense beams with well-defined neutron spectra, i.e. a ''cold neutron'' beam, a beam extracted from a thermal column and a beam of 0.3-eV neutrons produced by crystal diffraction. The B/T ratio exhibits a small and smooth variation in the energy range considered. This effect seems to be correlated with measurements of some other fission parameters in the same neutron-energy range. (author)

  16. Monte-Carlo simulation for fragment mass and kinetic energy distributions from neutron induced fission of 235U

    CERN Document Server

    Montoya, M; Rojas, J

    2007-01-01

    The mass and kinetic energy distribution of nuclear fragments from thermal neutron induced fission of 235U have been studied using a Monte-Carlo simulation. Besides reproducing the pronounced broadening on the standard deviation of the final fragment kinetic energy distribution $\\sigma_{e}(m)$ around the mass number m = 109, our simulation also produces a second broadening around m = 125, that is in agreement with the experimental data obtained by Belhafaf et al. These results are consequence of the characteristics of the neutron emission, the variation in the primary fragment mean kinetic energy and the yield as a function of the mass.

  17. Nuclear fission, the energy of the future; La fision nuclear como energia del futuro

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Val, J. M.; Fernandez, J. A.; Leon, P. T.

    2002-07-01

    The design of new-generation nuclear power stations incorporates approaches and control systems which significantly reduce risk and waste generation, while enhancing an installation's performance. This article reviews current programs involving the world's advanced reactors,and other future systems such as rapid reproduction reactors, or those operating in sub-critical conditions as energy amplifier. (Author) 12 refs.

  18. Advanced concepts for waste management and nuclear energy production in the EURATOM fifth framework programme

    International Nuclear Information System (INIS)

    This paper summarises the objectives of the research projects on Partitioning and Transmutation (P and T) of long lived radionuclides in nuclear waste and advanced systems for nuclear energy production in the key action on nuclear fission of the EURATOM Fifth Framework Programme (FP5) (1998-2002). As these FP5 projects cover the main aspects of P and T, they should provide a basis for evaluating the practicability, on an industrial scale, of P and T for reducing the amount of long lived radionuclides to be disposed of. Concerning advanced concepts, a cluster of projects is addressing the key technical issues to be solved before implementing High Temperature Reactors (HTRs) commercially for energy production. Finally, the European Commission(tm)s proposal for a New Framework Programme (2002-2006) is briefly outlined. (author)

  19. Advanced concepts for waste management and nuclear energy production in the EURATOM 5. framework programme

    International Nuclear Information System (INIS)

    This paper summarises the objectives of the research projects on partitioning and transmutation (P and T) of long-lived radionuclides in nuclear waste and advanced systems for nuclear energy production in the key action on nuclear fission of the EURATOM 5. Framework Programme (FP5) (1998-2002). As these FP5 projects cover the main aspects of P and T, they should provide a basis for evaluating the practicability, on an industrial scale, of P and T for reducing the amount of long-lived radionuclides to be disposed of. Concerning advanced concepts, a cluster of projects is addressing the key technical issues to be solved before implementing high-temperature reactors (HTRs) commercially for energy production. Finally, the European Commissions proposal fora New Framework Programme (2002-2006) is briefly outlined. (authors)

  20. Fission energy program of the U.S. Department of Energy

    International Nuclear Information System (INIS)

    The document describes programs managed by the Program Director for Nuclear Energy, Department of Energy, and under the cognizance of the Committee on Science and Technology, United States House of Representatives. The major portion of the document is concerned with civilian nuclear power development, the policy for which has been established by the National Energy Plan of April 1977, but it also includes descriptions of the space applications and naval reactor programs

  1. 1: the atom. 2: radioactivity. 3: man and radiations. 4: the energy. 5: nuclear energy: fusion and fission. 6: the operation of a nuclear reactor. 7: the nuclear fuel cycle

    International Nuclear Information System (INIS)

    This series of 7 digest booklets present the bases of the nuclear physics and of the nuclear energy: 1 - the atom (structure of matter, chemical elements and isotopes, the four fundamental interactions, nuclear physics); 2 - radioactivity (definition, origins of radioelements, applications of radioactivity); 3 - man and radiations (radiations diversity, biological effects, radioprotection, examples of radiation applications); 4 - energy (energy states, different forms of energy, characteristics); 5 - nuclear energy: fusion and fission (nuclear energy release, thermonuclear fusion, nuclear fission and chain reaction); 6 - operation of a nuclear reactor (nuclear fission, reactor components, reactor types); 7 - nuclear fuel cycle (nuclear fuel preparation, fuel consumption, reprocessing, wastes management). (J.S.)

  2. Spectroscopy of heavy fissionable nuclei

    Indian Academy of Sciences (India)

    S K Tandel

    2015-09-01

    Structural studies of heavy nuclei are quite challenging due to increased competition from fission, particularly at high spins. Nuclei in the actinide region exhibit a variety of interesting phenomena. Recent advances in instrumentation and analysis techniques have made feasible sensitive measurements of nuclei populated with quite low cross-sections. These include isomers and rotational band structures in isotopes of Pu ( = 94) to Rf ( = 104), and octupole correlations in the Th ( = 90) region. The obtained experimental data have provided insights on various aspects like moments of inertia and nucleon alignments at high spins, quasiparticle energies and evolution of quadrupole and octupole collectivity, among others. An overview of some of these results is presented.

  3. Advanced Energy Industries, Inc. SEGIS developments.

    Energy Technology Data Exchange (ETDEWEB)

    Scharf, Mesa P. (Advanced Energy Industries, Inc., Bend, OR); Bower, Ward Isaac; Mills-Price, Michael A. (Advanced Energy Industries, Inc., Bend, OR); Sena-Henderson, Lisa; David, Carolyn; Akhil, Abbas Ali; Kuszmaul, Scott S.; Gonzalez, Sigifredo

    2012-03-01

    The Solar Energy Grid Integration Systems (SEGIS) initiative is a three-year, three-stage project that includes conceptual design and market analysis (Stage 1), prototype development/testing (Stage 2), and commercialization (Stage 3). Projects focus on system development of solar technologies, expansion of intelligent renewable energy applications, and connecting large-scale photovoltaic (PV) installations into the electric grid. As documented in this report, Advanced Energy Industries, Inc. (AE), its partners, and Sandia National Laboratories (SNL) successfully collaborated to complete the final stage of the SEGIS initiative, which has guided new technology development and development of methodologies for unification of PV and smart-grid technologies. The combined team met all deliverables throughout the three-year program and commercialized a broad set of the developed technologies.

  4. Excitation energy dependence of fragment-mass distributions from fission of 180,190Hg formed in fusion reactions of 36Ar + 144,154Sm

    Directory of Open Access Journals (Sweden)

    K. Nishio

    2015-09-01

    Full Text Available Mass distributions of fission fragments from the compound nuclei 180Hg and 190Hg formed in fusion reactions 36Ar + 144Sm and 36Ar + 154Sm, respectively, were measured at initial excitation energies of E⁎(Hg180=33–66 MeV and E⁎(Hg190=48–71 MeV. In the fission of 180Hg, the mass spectra were well reproduced by assuming only an asymmetric-mass division, with most probable light and heavy fragment masses A¯L/A¯H=79/101. The mass asymmetry for 180Hg agrees well with that obtained in the low-energy β+/EC-delayed fission of 180Tl, from our earlier ISOLDE(CERN experiment. Fission of 190Hg is found to proceed in a similar way, delivering the mass asymmetry of A¯L/A¯H=83/107, throughout the measured excitation energy range. The persistence as a function of excitation energy of the mass-asymmetric fission for both proton-rich Hg isotopes gives strong evidence for the survival of microscopic effects up to effective excitation energies of compound nuclei as high as 40 MeV. This behavior is different from fission of actinide nuclei and heavier mercury isotope 198Hg.

  5. 1: the atom. 2: radioactivity. 3: man and radiations. 4: the energy. 5: nuclear energy: fusion and fission. 6: the operation of a nuclear reactor. 7: the nuclear fuel cycle; 1: l'atome. 2: la radioactivite. 3: l'homme et les rayonnements. 4: l'energie. 5: l'energie nucleaire: fusion et fission. 6: le fonctionnement d'un reacteur nucleaire. 7: le cycle du combustible nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    This series of 7 digest booklets present the bases of the nuclear physics and of the nuclear energy: 1 - the atom (structure of matter, chemical elements and isotopes, the four fundamental interactions, nuclear physics); 2 - radioactivity (definition, origins of radioelements, applications of radioactivity); 3 - man and radiations (radiations diversity, biological effects, radioprotection, examples of radiation applications); 4 - energy (energy states, different forms of energy, characteristics); 5 - nuclear energy: fusion and fission (nuclear energy release, thermonuclear fusion, nuclear fission and chain reaction); 6 - operation of a nuclear reactor (nuclear fission, reactor components, reactor types); 7 - nuclear fuel cycle (nuclear fuel preparation, fuel consumption, reprocessing, wastes management). (J.S.)

  6. The geo-reactor. A link between nuclear fission and geothermal energy?

    International Nuclear Information System (INIS)

    Recent high-precision isotope analysis data suggests the potential occurrence of a geo-reactor. Specific gas isotopes that could have been generated by binary and ternary fissions were identified in volcano emanations or as soluble/associated species in crystalline rocks and semi-quantitatively evaluated as isotopic ratio or estimated amounts. Presently if it is evident that according to the actinide inventory on the Earth, local potential criticality of the geo-system may have been reached, several questions remain such as why, where and when did a geo-reactor be operational? Even if the hypothesis of a geo-reactor operation in the proto-Earth period should be acceptable, it could be difficult to anticipate that a geo-reactor is still operating today. This could be tested in the future by assessing and reconstructing the system by antineutrino detection and tomography through the Earth. The present paper focuses on the geo-reactor conditions including history, spatial extension and regimes. The discussion based on recent calculations involves investigations on the limits in term of fissile inventory, size and power, based on stratification through the gravitational field and the various features through the inner mantel, the boundary with the core, the external part and the inner-core. the reconstruction allows to formulating that from the history point of view there are possibilities that the geo-reactor reached criticality in a proto-Earth period as a thorium/uranium reactor triggered by an under-layer with heavier actinides. The geo-reactor should be a key component of geothermal energy sources. (author)

  7. Saving Energy Through Advanced Power Strips (Poster)

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, D.

    2013-10-01

    Advanced Power Strips (APS) look just like ordinary power strips, except that they have built-in features that are designed to reduce the amount of energy used by many consumer electronics. There are several different types of APSs on the market, but they all operate on the same basic principle of shutting off the supply power to devices that are not in use. By replacing your standard power strip with an APS, you can signifcantly cut the amount of electricity used by your home office and entertainment center devices, and save money on your electric bill. This illustration summarizes the different options.

  8. Thermal-hydraulics deisgn and analysis of water-cooled energy production blanket for a fusion-fission hybrid reactor

    International Nuclear Information System (INIS)

    A conceptual design of fusion-fission hybrid reactor for energy production, named FDS-EM (Energy Multiplier), was proposed. It was preliminary designed to generate about an electricity power of about 1.0 GW with self-sustaining tritium cycle. This contribution performed the thermal-hydraulics design and analyses for FDS-EM water-cooled blanket. The typical thermal-hydraulics parameters were designed by using mature technologies of PWR, and temperature and stress analyses were carried out, according to typical parameters of the blanket. The results preliminarily demonstrated the engineering feasibility of the design. (authors)

  9. Monte-carlo simulation for fragment mass and kinetic energy distributions from neutron induced fission of 235U

    International Nuclear Information System (INIS)

    Mass and kinetic energy distribution of nuclear fragments after neutron induced fission of 235U have been studied using a Monte-Carlo simulation. Besides that the pronounced peak in the standard deviation of the kinetic energy σE(m) at the mass number around m = 110 was reproduced, a second peak was found at m = 126. These results are in good agreement with experimental data obtained by Belhafaf et. al. We have concluded that the obtained results are consequence of the characteristics of neutron evaporation for the fragments and sharp variation on primary mass yield curve. (authors)

  10. Monte-Carlo simulation for fragment mass and kinetic energy distributions from neutron-induce fission of 235U

    International Nuclear Information System (INIS)

    The mass and kinetic energy distribution of nuclear fragments after neutron-induced fission of 235U have been studied using a Monte-Carlo simulation. Besides reproducing the pronounced peak in the standard deviation of the kinetic energy σE(m) at the fragment mass number around m=109, our simulation also produces a second peak at about m=126. These results are in good agreement with experimental data obtained by Belhafaf et.al. We conclude that the obtained results are consequence of the characteristics of the fragments' neutron evaporation and of the sharp variation on the primary mass yield curve. (orig.)

  11. Measurement of multiplicity and total energy of gamma radiation following the U-235 fission induced by resonance neutrons

    International Nuclear Information System (INIS)

    The spectroscopy of γ-radiation following the fission of U-235 induced by resonance neutrons with energies from 0.7 eV to 36 eV from the IBR-30 pulsed source was studied. The ionization chamber containing 10 g of uranium enriched to 90% with U-235 and the Ge(Li) detector abour 30 cm3 in volume having an energy resolution of 2.8 keV at 1333 keV energy were operating in coincidence. The results were analysed within the multidimensional procedure. After reconstructing the measured spectrum the γ-spectrum in the energy range from 0.1 to 1.6 MeV has been obtained. The following integral characteristics have been calculated: multiplicity, total and average energies. The average energies for the 3- and 4- resonances are reported

  12. Fission Fragments Discriminator

    International Nuclear Information System (INIS)

    Nuclear fission reaction between Uranium-235 nucleus and thermal neutron caused the high energy fission fragments with uncertainly direction. The particle direction discrimination was determined. The 2.5 x 3.0 mm2 polyethylene gratings with 1-6 mm thickness were used. The grating was placed between uranium screen that fabricated from ammonium-diurinate compound and polycarbonate nuclear track film recorder irradiated by neutron from Thai Research Reactor (TRR-1/M1) facility. The nuclear track density was inversely with grating thickness. It's only fission fragments normal to uranium screen pass through film recorder when grating thickness was 4-6 mm

  13. Fusion--fision hybrid breeders: economic and performance issues, role of advanced converters, interdependence between fission and fusion programs

    International Nuclear Information System (INIS)

    This paper considers nuclear breeding systems (i.e., production of fissile fuel from fertile materials). The range of breeding technologies considered is deliberately wide. We include systems which breed by using internal neutron sources--a reactor-breeder, exemplified by the liquid metal fast breeder reactor (LMFBR)--and systems which breed by using external neutron sources--exemplified in this paper primarily by hybrid fusion-fission breeders

  14. Investigation of the prompt neutron emission mechanism in low energy fission of 235,233U(nth, f and 252Cf(sf

    Directory of Open Access Journals (Sweden)

    Val’ski G.V.

    2010-10-01

    Full Text Available A series of experiments has been performed to measure prompt neutron angular and energy distributions from thermal neutron-induced fission of 235,233U in correlation with the fission fragments. These distributions have been analyzed with the assumption of neutron isotropic emission from accelerated fission fragments. The performed analysis demonstrates that all obtained results can be described within 5% accuracy using this assumption. This discrepancy is approximately constant and doesn’t depend on fragment mass and the total kinetic energy (TKE. Some minor peculiarities of angular distribution may be interpreted as a result of anisotropy of the fission neutron angular distribution in the fragment center-of-mass system.

  15. Energy Theft in the Advanced Metering Infrastructure

    Science.gov (United States)

    McLaughlin, Stephen; Podkuiko, Dmitry; McDaniel, Patrick

    Global energy generation and delivery systems are transitioning to a new computerized "smart grid". One of the principle components of the smart grid is an advanced metering infrastructure (AMI). AMI replaces the analog meters with computerized systems that report usage over digital communication interfaces, e.g., phone lines. However, with this infrastructure comes new risk. In this paper, we consider adversary means of defrauding the electrical grid by manipulating AMI systems. We document the methods adversaries will use to attempt to manipulate energy usage data, and validate the viability of these attacks by performing penetration testing on commodity devices. Through these activities, we demonstrate that not only is theft still possible in AMI systems, but that current AMI devices introduce a myriad of new vectors for achieving it.

  16. Nanoporous metals for advanced energy technologies

    CERN Document Server

    Ding, Yi

    2016-01-01

    This book covers the state-of-the-art research in nanoporous metals for potential applications in advanced energy fields, including proton exchange membrane fuel cells, Li batteries (Li ion, Li-S, and Li-O2), and supercapacitors. The related structural design and performance of nanoporous metals as well as possible mechanisms and challenges are fully addressed. The formation mechanisms of nanoporous metals during dealloying, the microstructures of nanoporous metals and characterization methods, as well as miscrostructural regulation of nanoporous metals through alloy design of precursors and surface diffusion control are also covered in detail. This is an ideal book for researchers, engineers, graduate students, and government/industry officers who are in charge of R&D investments and strategy related to energy technologies.

  17. High density electronic excitation effects on microstructural evolution in CeO2 under irradiations with high energy fission products

    International Nuclear Information System (INIS)

    For progressing high burnup extension of LWR fuels, formation and growth mechanism of a crystallographic re-structuring in the periphery region of high burnup fuel pellets, as named 'rim structure', should be clarified. The structure shall be formed by the accumulation and mutual interactions of radiation damages, fission products (FPs) and electronic excitations deposited partially by nuclear fissions. In order to clarify electronic excitation effects on the microstructural evolution in CeO2, 70-210 MeV FP ions (Xe, I, Zr) irradiation examinations on CeO2 have been done at JAERI-Tandem facility. These experiments clarify that 1) the effective area of electronic excitation by high energy fission products might be around 5-7 mmφ, and the square of ion track diameter tends to be proportional to the electronic stopping power (Se), and 2) overlapping of ion tracks, under 210 MeV Xe irradiation to a fluence of 1x1015 ions/cm2, makes the surface to be rough, whose size of the roughness is around 1 μm. (author)

  18. Two parameter studies of TFD response to fission fragments for measurements of fragment mass and energy distributions

    International Nuclear Information System (INIS)

    A new technique involving detection of the pair fragments associated with each fission event by two thin film scintillators is investigated to determine its applicability for the determination of fragment mass and energy distributions. The thin film scintillation detectors (thickness 14 microns) were positioned on opposite sides of a VYNS backed 235U source of thickness 60/cm2 placed in a thermal neutron beam of flux 5 x 107 neutrons/cm2/sec. The coincident pulses from the two detectors were recorded event by event on a multi-parameter data acquisition system. The functional behaviour of the film response to fission fragments of specified E/M and Z was obtained by combining the specific luminescence and specific energy loss data for heavy ions. Using the mass and momentum conservation conditions and an iterative procedure it was possible to analyse the data event by event to obtain the fragment mass and kinetic energies. The mass and energy distributions and mass energy correlations so obtained are in good agreement with the published data based on solid state detector measurements. This technique can therefore be a good substitute for solid state detector based methods especially in those cases where radiation damage on solid state detectors is a serious problem. (author)

  19. Advanced energy projects FY 1997 research summaries

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-09-01

    The mission of the Advanced Energy Projects (AEP) program is to explore the scientific feasibility of novel energy-related concepts that are high risk, in terms of scientific feasibility, yet have a realistic potential for a high technological payoff. The concepts supported by the AEP are typically at an early stage of scientific development. They often arise from advances in basic research and are premature for consideration by applied research or technology development programs. Some are based on discoveries of new scientific phenomena or involve exploratory ideas that span multiple scientific and technical disciplines which do not fit into an existing DOE program area. In all cases, the objective is to support evaluation of the scientific or technical feasibility of the novel concepts involved. Following AEP support, it is expected that each concept will be sufficiently developed to attract further funding from other sources to realize its full potential. Projects that involve evolutionary research or technology development and demonstration are not supported by AEP. Furthermore, research projects more appropriate for another existing DOE research program are not encouraged. There were 65 projects in the AEP research portfolio during Fiscal Year 1997. Eigheen projects were initiated during that fiscal year. This document consists of short summaries of projects active in FY 1997. Further information of a specific project may be obtained by contacting the principal investigator.

  20. Measurement of the 238U to 235U fission cross-section ratio for neutron energies between 0.1 and 25 MeV

    International Nuclear Information System (INIS)

    The 238U to 235U fission cross-section ratio was measured for incident neutrons from 0.1 to 25.0 MeV. A ratio shape measurement was normalized by the threshold cross-section method. A fission cross-section ratio of 0.436 +- 0.004 was found averaged over neutron energies from 2.35 to 2.95 MeV. 8 figures, 12 tables

  1. World Energy Data System (WENDS). Volume XI. Nuclear fission program summaries

    International Nuclear Information System (INIS)

    Brief management and technical summaries of nuclear fission power programs are presented for nineteen countries. The programs include the following: fuel supply, resource recovery, enrichment, fuel fabrication, light water reactors, heavy water reactors, gas cooled reactors, breeder reactors, research and test reactors, spent fuel processing, waste management, and safety and environment

  2. Determination of neutron induced fission cross sections by surrogate reaction methods for nuclear energy applications

    International Nuclear Information System (INIS)

    In this talk, surrogate reaction methods are briefly discussed and presented. Some of the recent results on neutron induced fission cross section measurements carried out and the possibility of extending the measurements for determining (n,γ), (n,2n) and (n,p) reaction cross-sections by surrogate reaction method are also discussed

  3. HYPERFUSE: a hypervelocity inertial confinement system for fusion energy production and fission waste transmutation

    International Nuclear Information System (INIS)

    Parametric system studies of an inertial confinement fusion (ICF) reactor system to transmute fission products from a LWR economy have been carried out. The ICF reactors would produce net power in addition to transmuting fission products. The particular ICF concept examined is an impact fusion approach termed HYPERFUSE, in which hypervelocity pellets, traveling on the order of 100 to 300 km/sec, collide with each other or a target block in a reactor chamber and initiate a thermonuclear reaction. The DT fusion fuel is contained in a shell of the material to be transmuted, e.g., 137Cs, 90Sr, 129I, 99Tc, etc. The 14-MeV fusion neutrons released during the pellet burn cause transmutation reactions (e.g., (n,2n), (n,α), (n,γ), etc.) that convert the long-lived fission products (FP's) either to stable products or to species that decay with a short half-life to a stable product. The transmutation parametric studies conclude that the design of the hypervelocity projectiles should emphasize the achievement of high densities in the transmutation regions (greater than the DT fusion fuel density), as well as the DT ignition and burn criterion (rho R = 1.0 to 3.0) requirements. These studies also indicate that masses on the order of 1.0 g at densities of rho greater than or equal to 500.0 g/cm3 are required for a practical fusion-based fission product transmutation system

  4. Singlet Exciton Fission for Solar Cell Applications: Energy Aspects of Interchromophore Coupling

    Czech Academy of Sciences Publication Activity Database

    Greyson, E. C.; Stepp, Brian R.; Chen, X.; Schwerin, A. F.; Paci, I.; Smith, M. B.; Akdag, A.; Johnson, J. C.; Nozik, A. J.; Michl, Josef; Ratner, M. A.

    2010-01-01

    Roč. 114, č. 45 (2010), s. 14223-14232. ISSN 1520-6106 R&D Projects: GA MŠk ME09114 Institutional research plan: CEZ:AV0Z40550506 Keywords : photophysics * singlet fission * DFT Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.603, year: 2010

  5. World Energy Data System (WENDS). Volume XI. Nuclear fission program summaries

    Energy Technology Data Exchange (ETDEWEB)

    1979-06-01

    Brief management and technical summaries of nuclear fission power programs are presented for nineteen countries. The programs include the following: fuel supply, resource recovery, enrichment, fuel fabrication, light water reactors, heavy water reactors, gas cooled reactors, breeder reactors, research and test reactors, spent fuel processing, waste management, and safety and environment. (JWR)

  6. Interpretation of the low-energy fission process in the framework of dinuclear system conception

    International Nuclear Information System (INIS)

    The possibility of the interpretation of fission of heavy nuclei as the process of formation, evolution, and decay of a dinuclear system is discussed. The interpretation is based on the nuclear interaction data obtained in heavy-ion nuclear physics investigations.

  7. Neutronics design and analysis of water-cooled energy production blanket for a fusion-fission hybrid reactor

    International Nuclear Information System (INIS)

    Neutronics calculations were performed to analysis the parameters of blanket energy multiplication factor (M) and tritium breeding ratio (TBR) in a fusion-fission hybrid reactor for energy production named FDS-EM (Energy Multiplier) blanket. The most significant and main goal of the water-cooled FDS-EM blanket is to achieve the energy gain of about 1 GW with self-sustaining tritium, which can operate for as long as possible without fuel unloading and reloading. The preliminarily designed neutronics parameters for FDS-EM were presented, which show that the blanket loaded with the Nuclear Waste (transuranic from 33 000 MWD/MTU PWR and depleted uranium) for energy multiplication (M≅90) with tritium self-sufficiency can operate for at least 10 years without fuel unloading and reloading. (authors)

  8. 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.

  9. 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.

  10. Advances in High Energy Materials (Review Paper

    Directory of Open Access Journals (Sweden)

    U. R. Nair

    2010-03-01

    Full Text Available Research and development efforts for realizing higher performance levels of high energy materials (HEMs are continued unabated all over the globe. Of late, it is becoming increasingly necessary to ensure that such materials are also eco-friendly. This has provided thrust to research in the area of force multiplying HEMs and compounds free from pollution causing components. Enhancement of the performance necessitates introduction of strained structure or increase in oxygen balance to achieve near stoichiometry. The search for environment friendly molecules is focused on chlorine free propellant compositions and lead free primary explosives. Energetic polymers offer added advantage of partitioning of energy and thus not necessitating the concentration of only solid components (HEMs and metal fuels in the formulations, to achieve higher performance, thereby leading to improvement in energetics without adversely affecting the processability and mechanical properties. During recent times, research in the area of insensitive explosives has received impetus particularly with the signature of STANAG. This paper gives a review of the all-round advances in the areas of HEMs encompassing oxidizers, high-energy dense materials, insensitive high-energy materials, polymers and plasticizers. Selected formulations based on these materials are also included.Defence Science Journal, 2010, 60(2, pp.137-151, DOI:http://dx.doi.org/10.14429/dsj.60.327

  11. Biomass energy conversion: conventional and advanced technologies

    International Nuclear Information System (INIS)

    Increasing interest in biomass energy conversion in recent years has focused attention on enhancing the efficiency of technologies converting biomass fuels into heat and power, their capital and operating costs and their environmental emissions. Conventional combustion systems, such as fixed-bed or grate units and entrainment units, deliver lower efficiencies (<25%) than modem coal-fired combustors (30-35%). The gasification of biomass will improve energy conversion efficiency and yield products useful for heat and power generation and chemical synthesis. Advanced biomass gasification technologies using pressurized fluidized-bed systems, including those incorporating hot-gas clean-up for feeding gas turbines or fuel cells, are being demonstrated. However, many biomass gasification processes are derivatives of coal gasification technologies and do not exploit the unique properties of biomass. This paper examines some existing and upcoming technologies for converting biomass into electric power or heat. Small-scale 1-30 MWe units are emphasized, but brief reference is made to larger and smaller systems, including those that bum coal-biomass mixtures and gasifiers that feed pilot-fuelled diesel engines. Promising advanced systems, such as a biomass integrated gasifier/gas turbine (BIG/GT) with combined-cycle operation and a biomass gasifier coupled to a fuel cell, giving cycle efficiencies approaching 50% are also described. These advanced gasifiers, typically fluid-bed designs, may be pressurized and can use a wide variety of biomass materials to generate electricity, process steam and chemical products such as methanol. Low-cost, disposable catalysts are becoming available for hot-gas clean-up (enhanced gas composition) for turbine and fuel cell systems. The advantages, limitations and relative costs of various biomass gasifier systems are briefly discussed. The paper identifies the best known biomass power projects and includes some information on proposed and

  12. Prompt Neutrons from Fission

    International Nuclear Information System (INIS)

    A survey is given of the present state of knowledge of the spectrum, angular distribution and number of prompt fission neutrons, as functions of incident neutron energy and individual fragment mass, for low-energy fission. The energy spectrum of prompt neutrons has been found to be of the same form (nearly Maxwellian) for many different types of fission. It has been shown that this type of spectrum is to be expected on the basis of evaporation from moving fragments, and theoretical predictions of the spectrum agree very accurately with experimental data. Some data are now available on the variation of the neutron spectrum with fragment mass and angle of emission. Only recently has it become possible to take accurate data on the angular distribution of the neutrons. It appears that the neutrons have the angular distribution to be expected if emitted almost isotropically from the moving fragments, with a possibility that some small fraction are not emitted in this way, but directly from the fissioning nuclide. Much work has been done on the variation of fission neutron number v with incident neutron energy for neutron-induced fission. The neutron number increases roughly linearly with energy, with a slope of about 0.15 n/MeV. There is now evidence that this slope changes somewhat with energy. This change must be associated with other changes in the-fission process. The most interesting recent discovery concerning fission neutrons is the strong dependence of neutron number on individual fragment mass. The data are being rapidly improved by means of the newer techniques of determining fragment mass yields from velocity and pulse-height data, and of determining neutron yields from cumulative mass yields. There is evidence of similar dependence of neutron yield on fragment mass in a number of cases. It has been suggested that this property is directly connected with the deformability of the fragments, and in particular with the near-spherical shapes of magic

  13. Effect of transverse vibrations of fissile nuclei on the angular and spin distributions of low-energy fission fragments

    Science.gov (United States)

    Bunakov, V. E.; Kadmensky, S. G.; Lyubashevsky, D. E.

    2016-05-01

    It is shown that A. Bohr's classic theory of angular distributions of fragments originating from low-energy fission should be supplemented with quantum corrections based on the involvement of a superposition of a very large number of angular momenta L m in the description of the relative motion of fragments flying apart along the straight line coincidentwith the symmetry axis. It is revealed that quantum zero-point wriggling-type vibrations of the fissile system in the vicinity of its scission point are a source of these angular momenta and of high fragment spins observed experimentally.

  14. Advances of energy drivers at Osaka

    International Nuclear Information System (INIS)

    The energy driver development at the Institute of Laser Engineering (ILE), Osaka University, comprises three fields; glass, laser, carbon dioxide laser, and relativistic electron beam. The development of reliable glass lasers has been the main program at ILE. The GEKKO 12 module program was carried out in the fiscal years from 1977 to 1979 in order to develop various laser components and subsystems which are necessary to construct a 20 kJ GEKKO 12 glass laser. The measured gain coefficient of the 200 mm disk amplifier was 0.10/cm corresponding to the αD product of 4.0. The expected peak output power of the system was 2 TW at 0.1 ns and 0.9 kJ at 1 ns. The recent advances in coating techniques will enable to operate this system over 1.3 kJ per beam at 3 ns. Carbon dioxide lasers have been developed as efficient high energy lasers to study the wave length scaling of implosion process. The design and construction of the 10 kJ LEKKO 8 laser system are in progress. Relativistic electron beam machines, being the most cost-effective driver, have been studied to control pulsed power and to investigate electron beam plasma interaction. As the future plans of ILE, the construction of a 100 kJ energy driver from 1958 to 1987 for scientific break-even experiments is considered. (Kato, T.)

  15. Spontaneous Fission

    Science.gov (United States)

    Segre, Emilio

    1950-11-22

    The first attempt to discover spontaneous fission in uranium was made by [Willard] Libby, who, however, failed to detect it on account of the smallness of effect. In 1940, [K. A.] Petrzhak and [G. N.] Flerov, using more sensitive methods, discovered spontaneous fission in uranium and gave some rough estimates of the spontaneous fission decay constant of this substance. Subsequently, extensive experimental work on the subject has been performed by several investigators and will be quoted in the various sections. [N.] Bohr and [A.] Wheeler have given a theory of the effect based on the usual ideas of penetration of potential barriers. On this project spontaneous fission has been studied for the past several years in an effort to obtain a complete picture of the phenomenon. For this purpose the spontaneous fission decay constants {lambda} have been measured for separated isotopes of the heavy elements wherever possible. Moreover, the number {nu} of neutrons emitted per fission has been measured wherever feasible, and other characteristics of the spontaneous fission process have been studied. This report summarizes the spontaneous fission work done at Los Alamos up to January 1, 1945. A chronological record of the work is contained in the Los Alamos monthly reports.

  16. Assessment of fission product yields data needs in nuclear reactor applications

    International Nuclear Information System (INIS)

    Studies on the build-up of fission products in fast reactors have been performed, with particular emphasis on the effects related to the physics of the nuclear fission process. Fission product yields, which are required for burn-up calculations, depend on the proton and neutron number of the target nucleus as well as on the incident neutron energy. Evaluated nuclear data on fission product yields are available for all relevant target nuclides in reactor applications. However, the description of their energy dependence in evaluated data is still rather rudimentary, which is due to the lack of experimental fast fission data and reliable physical models. Additionally, physics studies of evaluated JEFF-3.1.1 fission yields data have shown potential improvements, especially for various fast fission data sets of this evaluation. In recent years, important progress in the understanding of the fission process has been made, and advanced model codes are currently being developed. This paper deals with the semi-empirical approach to the description of the fission process, which is used in the GEF code being developed by K.-H. Schmidt and B. Jurado on behalf of the OECD Nuclear Energy Agency, and with results from the corresponding author's diploma thesis. An extended version of the GEF code, supporting the calculation of spectrum weighted fission product yields, has been developed. It has been applied to the calculation of fission product yields in the fission rate spectra of a MOX fuelled sodium-cooled fast reactor. Important results are compared to JEFF-3.1.1 data and discussed in this paper. (authors)

  17. Variation of Fission-Fragment Kinetic Energy Distribution, Mass Distribution, and Yield of Long-Range Alpha Particles in the Resonance-Neutron-Induced Fission of U235 and Pu239

    International Nuclear Information System (INIS)

    These measurements were undertaken to obtain additional information on the fission process, and to investigate the application of this information to the assignment of J-values to resonance levels, as the usual methods of determining J-values are of limited applicability in the case of fissile isotopes. An earlier study of U235 showed that the fission-fragment kinetic energy and the alpha yield varied significantly from level to level, and fell into two groups suggestive of the two possible J-values. The present paper reports on measurements on Pu239. A study of 19 levels shows 15 levels with high average kinetic energy and 4 levels with low average kinetic energy, the former being assigned J -1 and the latter J = 0 on the basis of the expected ratio of population of the two spin states and also for maximum compatibility with other determinations. Some variation of relative alpha-particle yield was found. It is concluded that (1) there are definite variations of kinetic energy of the fragments from level to level; (2) the variation in the case of U235 is correlated with the relative yield of symmetric fission; (3) there is some indication in the case of Pu239 that the variation of fragment energy is correlated with the J-values; and (4) the relative yield of alpha particles varies in an expected fashion. (author)

  18. Mass yields in the reaction 235U(nsub(th),f) as a function of the kinetic energy and ion charge of the fission products

    International Nuclear Information System (INIS)

    In this paper measurements of mass- and ioncharge distributions of the lower mass 235U(nsub(th),f)-fission products, performed with the 'Lohengrin' recoil spectrometer of the Institut Lane-Langevin at Grenoble, are reported. The uranium targets used led to an energy loss of the fission fragments of only 1 to 2 MeV, so their energy was well defined. The mass abundance have been measured for the following fragment energies: E = 83.6, 88.5, 93.4, 98.3, 103.1, 108.0, 112.0 MeV. The energy integrated mass distributions were compared with recent data collections of fission yields. For nearly all masses the abundancies agree well within the limits of error. So these maesurements can be used as an independent source of data. (orig./RW)

  19. Odd-even proton effect in the distribution of fission products at low and medium energy

    International Nuclear Information System (INIS)

    After description of the empirical representations of the fission products distribution, the influence of the odd-even proton effect, favouring even atomic number fragments is discussed using the experimental evaluation of the parameters: most probable charge width of the charge distribution of the second-order centered moment, mean charge, second-order centered moment. We show that, in the presence of the odd-even effects, the true value of the second-order centered moment can be deduced from the fractional yields for the isotopes of a given element. Then the odd-even effect can be estimated by the analysis of the observed yields. The method is applied to the fission of 232Th and 238U by 14 MeV-neutrons

  20. Distributed sensor coordination for advanced energy systems

    Energy Technology Data Exchange (ETDEWEB)

    Tumer, Kagan [Oregon State Univ., Corvallis, OR (United States). School of Mechanical, Industrial and Manufacturing Engineering

    2015-03-12

    Motivation: The ability to collect key system level information is critical to the safe, efficient and reliable operation of advanced power systems. Recent advances in sensor technology have enabled some level of decision making directly at the sensor level. However, coordinating large numbers of sensors, particularly heterogeneous sensors, to achieve system level objectives such as predicting plant efficiency, reducing downtime or predicting outages requires sophisticated coordination algorithms. Indeed, a critical issue in such systems is how to ensure the interaction of a large number of heterogenous system components do not interfere with one another and lead to undesirable behavior. Objectives and Contributions: The long-term objective of this work is to provide sensor deployment, coordination and networking algorithms for large numbers of sensors to ensure the safe, reliable, and robust operation of advanced energy systems. Our two specific objectives are to: 1. Derive sensor performance metrics for heterogeneous sensor networks. 2. Demonstrate effectiveness, scalability and reconfigurability of heterogeneous sensor network in advanced power systems. The key technical contribution of this work is to push the coordination step to the design of the objective functions of the sensors, allowing networks of heterogeneous sensors to be controlled. By ensuring that the control and coordination is not specific to particular sensor hardware, this approach enables the design and operation of large heterogeneous sensor networks. In addition to the coordination coordination mechanism, this approach allows the system to be reconfigured in response to changing needs (e.g., sudden external events requiring new responses) or changing sensor network characteristics (e.g., sudden changes to plant condition). Impact: The impact of this work extends to a large class of problems relevant to the National Energy Technology Laboratory including sensor placement, heterogeneous sensor

  1. Experimental Neutron-Induced Fission Fragment Mass Yields of 232Th and 238U at Energies from 10 to 33 MeV

    OpenAIRE

    Simutkin, V. D.; Pomp, S.; Blomgren, J.; Österlund, M.; R. Bevilacqua; Ryzhov, I. V.; Tutin, G. A.; Yavshits, S. G.; Vaishnene, L. A.; Onegin, M S; Meulders, J.P.; Prieels, R.

    2013-01-01

    Development of nuclear energy applications requires data for neutron-induced reactions for actinides in a wide neutron energy range. Here we describe measurements of pre-neutron emission fission fragment mass yields of 232Th and 238U at incident neutron energies from 10 to 33 MeV. The measurements were done at the quasi-monoenergetic neutron beam of the Louvain-la-Neuve cyclotron facility CYCLONE; a multi-section twin Frisch-gridded ionization chamber was used to detect fission fragments. For...

  2. HYPERFUSE: a hypervelocity inertial confinement system for fusion energy production and fission waste transmutation

    International Nuclear Information System (INIS)

    Parametric system studies of an inertial confinement fusion (ICF) reactor system to transmute fission products from an LWR economy have been carried out. The ICF reactors would produce net power in addition to transmuting fission products. The particular ICF concept examined is an impact fusion approach termed HYPERFUSE, in which hypervelocity pellets, traveling on the order of 100 to 300 km/sec, collide with each other or a target block in a reactor chamber and initiate a thermonuclear reaction. The DT fusion fuel is contained in a shell of the material to be transmuted, e.g., 137Cs, 90Sr, 129I, 99Tc, etc. The 14-MeV fusion neutrons released during the pellet burn cause transmutation reactions (e.g., (n,2n), (n,α), (n,γ), etc.) that convert the long-lived fission products (FP's) either to stable products or to species that decay with a short half-life to a stable product. The transmutation parametric studies conclude that the design of the hypervelocity projectiles should emphasize the achievement of high densities in the transmutation regions (greater than the DT fusion fuel density), as well as the DT ignition and burn criterion (rho R=1.0 to 3.0) requirements

  3. Advanced Dark Energy Physics Telescope (ADEPT)

    Energy Technology Data Exchange (ETDEWEB)

    Charles L. Bennett

    2009-03-26

    In 2006, we proposed to NASA a detailed concept study of ADEPT (the Advanced Dark Energy Physics Telescope), a potential space mission to reliably measure the time-evolution of dark energy by conducting the largest effective volume survey of the universe ever done. A peer-review panel of scientific, management, and technical experts reported back the highest possible 'excellent' rating for ADEPT. We have since made substantial advances in the scientific and technical maturity of the mission design. With this Department of Energy (DOE) award we were granted supplemental funding to support specific extended research items that were not included in the NASA proposal, many of which were intended to broadly advance future dark energy research, as laid out by the Dark Energy Task Force (DETF). The proposed work had three targets: (1) the adaptation of large-format infrared arrays to a 2 micron cut-off; (2) analytical research to improve the understanding of the dark energy figure-of- merit; and (3) extended studies of baryon acoustic oscillation systematic uncertainties. Since the actual award was only for {approx}10% of the proposed amount item (1) was dropped and item (2) work was severely restricted, consistent with the referee reviews of the proposal, although there was considerable contradictions between reviewer comments and several comments that displayed a lack of familiarity with the research. None the less, item (3) was the focus of the work. To characterize the nature of the dark energy, ADEPT is designed to observe baryon acoustic oscillations (BAO) in a large galaxy redshift survey and to obtain substantial numbers of high-redshift Type Ia supernovae (SNe Ia). The 2003 Wilkinson Microwave Anisotropy Probe (WMAP) made a precise determination of the BAO 'standard ruler' scale, as it was imprinted on the cosmic microwave background (CMB) at z {approx} 1090. The standard ruler was also imprinted on the pattern of galaxies, and was first

  4. Contribution to the study of nuclear fission

    International Nuclear Information System (INIS)

    The author proposes an overview of his research activity during the past fifteen years and more particularly that dealing with nuclear fission. The first part reports works on nucleus physics at the scission via the investigation of ternary fission (experimental procedure, influence of fission modes, influence of resonance spin, influence of excitation energy of the fissioning nucleus, emission probabilities, energy spectra of ternary alphas and tritons, emission mechanism). The second part reports measurements and assessments of neutron-induced fission cross sections. The third part reports the investigation of some properties of fission products (efficiencies, branching ratios of the main delayed neutron precursors)

  5. Consultancy on the potential of fusion/fission sub-critical neutron systems for energy production and transmutation. Working material

    International Nuclear Information System (INIS)

    The Workshop on Sub-critical Neutron Production held at the University of Maryland and the Eisenhower Institute on 11-13 October 2004 brought together members of fusion, fission and accelerator technical communities to discuss issues of spent fuel, nonproliferation, reactor safety and the use of neutrons for sub-critical operation of nuclear reactors. The Workshop strongly recommended that the fusion community work closely with other technical communities to ensure that a wider range of technical solutions is available to solve the spent fuel problem and to utilize the current actinide inventories. Participants of the Workshop recommended that a follow-on Workshop, possibly under the aegis of the IAEA, should be held in the first half of the year 2005. The Consultancy Meeting is the response to this recommendation. The objectives of the Consultancy meeting were to hold discussions on the role of fusion/fission systems in sub-critical operations of nuclear reactors. The participants agreed that development of innovative (fourth generation) fission reactors, advanced fuel cycle options, and disposition of existing spent nuclear fuel inventories in various Member Sates can significantly benefit from including sub-critical systems, which are driven by external neutron sources. Spallation neutrons produced by accelerators have been accepted in the past as the means of driving sub-critical reactors. The accelerator community deserves credit in pioneering this novel approach to reactor design. Progress in the design and operation of fusion devices now offers additional innovative means, broadening the range of sub-critical operations of fission reactors. Participants felt that fusion should participate with accelerators in providing a range of technical options in reactor design. Participants discussed concrete steps to set up a small fusion/fission system to demonstrate actinide burning in the laboratory and what advice should be given to the Agency on its role in

  6. Advanced Energy Efficiency and Distributed Renewables

    Science.gov (United States)

    Lovins, Amory

    2007-04-01

    The US now wrings twice the GDP from each unit of energy that it did in 1975. Reduced energy intensity since then now provides more than twice as much service as burning oil does. Yet still more efficient end-use of energy -- explained more fully in a companion workshop offered at 1245 -- is the largest, fastest, cheapest, most benign, least understood, and least harnessed energy resource available. For example, existing technologies could save half of 2000 US oil and gas and three-fourths of US electricity, at lower cost than producing and delivering that energy from existing facilities. Saving half the oil through efficiency and replacing the other half with saved natural gas and advanced biofuels would cost an average of only 15/barrel and could eliminate US oil use by the 2040s, led by business for profit. Efficiency techniques and ways to combine and apply them continue to improve faster than they're applied, so the ``efficiency resource'' is becoming ever larger and cheaper. As for electricity, ``micropower'' (distributed renewables plus low-carbon cogeneration) is growing so quickly that by 2005 it provided a sixth of the world's electricity and a third of its new electricity, and was adding annually 4x the capacity and 11x the capacity added by nuclear power, which it surpassed in capacity in 2002 and in output in 2006. Together, micropower and ``negawatts'' (saved electricity) now provide upwards half the world's new electrical services, due to their far lower cost and lower financial risk than the central thermal power stations that still dominate policy discussions. For oil and electricity, each of which adds about two-fifths of the world's energy-related carbon dioxide emissions, efficiency plus competitive alternative supplies can stabilize the earth's climate at a profit, as well as solving the oil and (largely) the nuclear proliferation problems. Conversely, costlier and slower options, notably nuclear power, would displace less carbon emission per

  7. Effects of Neutron Emission on Fragment Mass and Kinetic Energy Distribution from Thermal Neutron-Induced Fission of 235U

    International Nuclear Information System (INIS)

    The mass and kinetic energy distribution of nuclear fragments from thermal neutron-induced fission of 235U(nth,f) have been studied using a Monte-Carlo simulation. Besides reproducing the pronounced broadening in the standard deviation of the kinetic energy at the final fragment mass number around m = 109, our simulation also produces a second broadening around m = 125. These results are in good agreement with the experimental data obtained by Belhafaf et al. and other results on yield of mass. We conclude that the obtained results are a consequence of the characteristics of the neutron emission, the sharp variation in the primary fragment kinetic energy and mass yield curves. We show that because neutron emission is hazardous to make any conclusion on primary quantities distribution of fragments from experimental results on final quantities distributions

  8. Analysis of Intermediate-Energy Nucleus-Nucleus Spallation, Fission, and Fragmentation Reactions with the LAQGSM code

    CERN Document Server

    Mashnik, S G; Prael, R E; Sierk, A J

    2003-01-01

    The LAQGSM code has been recently developed at Los Alamos National Laboratory to simulate nuclear reactions for proton radiography applications. We have benchmarked our code against most available measured data both for proton-nucleus and nucleus-nucleus interactions at incident energies from 10 MeV to 800 GeV and have compared our results with predictions of other current models used by the nuclear community. Here, we present a brief description of our code and show illustrative results obtained with LAQGSM for neutron spectra measured recently by Nakamura's groups for reactions induced by light and medium nuclei on targets from C to Pb at several incident energies from 95 to 600 MeV/nucleon and with the recent GSI measurements of spallation, fission, and fragmentation yields from A+p and A+A reactions at incident energies near and below 1 GeV/nucleon. Further necessary work is outlined.

  9. 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...

  10. Dynamics of fission and heavy ion reactions

    International Nuclear Information System (INIS)

    Recent advances in a unified macroscopic-microscopic description of large-amplitude collective nuclear motion such as occurs in fission and heavy ion reactions are discussed. With the goal of finding observable quantities that depend upon the magnitude and mechanism of nuclear dissipation, one-body dissipation and two-body viscosity within the framework of a generalized Fokker-Planck equation for the time dependence of the distribution function in phase space of collective coordinates and momenta are considered. Proceeding in two separate directions, the generalized Hamilton equations of motion for the first moments of the distribution function with a new shape parametrization and other technical innovations are first solved. This yields the mean translational fission-fragment kinetic energy and mass of a third fragment that sometimes forms between the two end fragments, as well as the energy required for fusion in symmetric heavy-ion reactions and the mass transfer and capture cross section in asymmetric heavy-ion reactions. In a second direction, we specialize to an inverted-oscillator fission barrier and use Kramers' stationary solution to calculate the mean time from the saddle point to scission for a heavy-ion-induced fission reaction for which experimental information is becoming available. 25 references

  11. 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

  12. 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...

  13. Fission Fragment Folding Angle Distributions for the Systems 11B+237Np, 12C+236U, and 16O+232Th in the Energy Range 1.1B<2.1

    International Nuclear Information System (INIS)

    Fission fragment folding angle distributions have been measured for the systems 11B+237Np, 12C+236U, and 16O+232Th, populating the same compound nucleus (248Cf) and at similar excitation energies (Ex 45-100 MeV). The full momentum transfer and incomplete momentum transfer fusion-fission components have been separated over the bombarding energy range 1.1c.m/VB 2.1. It is observed that the largest value of the ratio of the transfer fission to the total fission is around 10 to 15% at the highest energy investigated. Over the energy range mentioned above, it is found that the transfer fission corrected fission fragment anisotropies are not significantly different from the values already obtained from the analysis of the total fission data reported earlier and hence the conclusions reached from the inclusive data remain unchanged. The anisotropy data were analyzed for the two cases corresponding to fission events with sizable fission barriers (Bf>T) and with smaller fission barriers (Bf>T). It was interesting to find that the effective moment of inertia (Jeff) values deduced from the latter component were consistent with the values from Sierk prescription used in the former case

  14. Study of heavy ion induced fission fragment angular and mass distribution at near and sub-coulomb barrier energies

    OpenAIRE

    Ghosh, T.K.

    2005-01-01

    The thesis presents investigations on the angular and mass distribution of fission fragments on heavy ion induced fission reactions. The present investigations address current issues in heavy ion induced fission reactions like finding the optimum entrance channel for the synthesis of super heavy elements (SHE). A double arm time of flight spectrometer over long flight path was used to measure the precise masses of complementary fission fragments. Necessary large area position sensitive gas de...

  15. Influence of complete energy sorting on the characteristics of the odd-even effect in fission-fragment element distributions

    OpenAIRE

    Jurado, Beatriz; Schmidt, Karl-Heinz

    2014-01-01

    The characteristics of the odd-even effect in fission-fragment Z distributions are compared to a model based on statistical mechanics. Special care is taken for using a consistent description for the influence of pairing correlations on the nuclear level density. The variation of the odd-even effect with the mass of the fissioning nucleus and with fission asymmetry is explained by the important statistical weight of configurations where the light nascent fission fragment populates the lowest ...

  16. Amount and activity of fission products which will be obtainable in France in the immediate future taking into account the development of atomic energy

    International Nuclear Information System (INIS)

    By using the Wigner and Way formula, the activity of the complex mixture of fission products produced in a pile may be estimated theoretically in advance. This study was carried out on the basis of forecasts, in the case of France for the production of electricity of atomic origin up to the year 1975. The uranium was assumed to be in the pile during periods of three months and six months. It is also possible to find the activity of a particular fission product and to give its decay rate. The element chosen is strontium for a three months' activation period. Each set of curves gives at any moment the total activity accumulated, and the characteristic activity of the fission products corresponding to a given half-life. (author)

  17. Distributed Sensor Coordination for Advanced Energy Systems

    Energy Technology Data Exchange (ETDEWEB)

    Tumer, Kagan

    2013-07-31

    The ability to collect key system level information is critical to the safe, efficient and reli- able operation of advanced energy systems. With recent advances in sensor development, it is now possible to push some level of decision making directly to computationally sophisticated sensors, rather than wait for data to arrive to a massive centralized location before a decision is made. This type of approach relies on networked sensors (called “agents” from here on) to actively collect and process data, and provide key control deci- sions to significantly improve both the quality/relevance of the collected data and the as- sociating decision making. The technological bottlenecks for such sensor networks stem from a lack of mathematics and algorithms to manage the systems, rather than difficulties associated with building and deploying them. Indeed, traditional sensor coordination strategies do not provide adequate solutions for this problem. Passive data collection methods (e.g., large sensor webs) can scale to large systems, but are generally not suited to highly dynamic environments, such as ad- vanced energy systems, where crucial decisions may need to be reached quickly and lo- cally. Approaches based on local decisions on the other hand cannot guarantee that each agent performing its task (maximize an agent objective) will lead to good network wide solution (maximize a network objective) without invoking cumbersome coordination rou- tines. There is currently a lack of algorithms that will enable self-organization and blend the efficiency of local decision making with the system level guarantees of global decision making, particularly when the systems operate in dynamic and stochastic environments. In this work we addressed this critical gap and provided a comprehensive solution to the problem of sensor coordination to ensure the safe, reliable, and robust operation of advanced energy systems. The differentiating aspect of the proposed work is in shift- ing

  18. Nuclear-fission studies with relativistic secondary beams: analysis of fission channels

    OpenAIRE

    Boeckstiegel, C.; Steinhaeuser, S.; Schmidt, K.-H.; Clerc, H. -G.; Grewe, A.; Heinz, A.; de Jong, M; JUNGHANS A. R.; Mueller, J.; Voss, B.

    2007-01-01

    Nuclear fission of several neutron-deficient actinides and pre-actinides from excitation energies around 11 MeV was studied at GSI Darmstadt by use of relativistic secondary beams. The characteristics of multimodal fission of nuclei around 226Th are systematically investigated and interpreted as the superposition of three fission channels. Properties of these fission channels have been determined for 15 systems. A global view on the properties of fission channels including previous results is...

  19. An indirect-drive non-cryogenic double-shell path to 1ω Nd-laser hybrid inertial fusion-fission energy

    International Nuclear Information System (INIS)

    A high-yield, room temperature, double-shell target design using a Nd : glass laser driver at the fundamental frequency 1ω is developed for hybrid inertial fusion-fission energy generation (Moses et al 2009 Fusion Sci. Technol. 56 547). The associated 4-10x fission energy gain relaxes the gain requirements of the fusion driver, enabling the prospect of a volume-ignition target with high thermonuclear burn fraction, simplified (1ω) laser operations from a quasi-impulsive power history, room temperature fielding, minimal shock-timing requirements and reduced risk of plasma-mediated laser backscatter with a vacuum hohlraum.

  20. Use of Microporous Nuclear Fuels as a Means of Utilizing the Kinetic Energy of Fission Products in Chemical Synthesis

    International Nuclear Information System (INIS)

    The paper begins by briefly outlining possible uses of the kinetic energy of fission products in the case of gaseous phase weak G reactions. The problem is mainly one of the amount of energy available; industrial production would require ionizing radiation energies of several tens of megawatts. At the second Geneva Conference (September 1958), some of the present authors proposed, for the first time, the use of microporous nuclear fuels as a solution. A body of supplementary data obtained with these fuels in given; they refer to decomposition of N2O, methane radiolysis, and fixation of nitrogen in the form of oxides. The results of the experiments are described with reference to the following parameters: radiation dose, type of radiation, type and dimensions of the microporous support surface. This work confirms the existence of a phenomenon which we term 'heterogeneous radiocatalysis' and enables its nature to be better defined. The nitrogen fixation reaction carried out with these fuels has some interesting features. In some cases, the rate of formation of the nitrogen oxides varies little for oxygen burn-up rates ranging up to 50%. The apparent G, calculated with reference to the total fission energy dissipated in the ''solid/ reactive gas'' system varies, according to case, from 0.1 to 0.4. The temperature is 80o C and the pressure approximately 25 atmospheres. A thorough study of the microstructure of the solids used has been begun, and the spectrum of the pores has been measured. A rough theoretical sketch of the phenomenon of ''heterogenous radiocatalysis'' is tentatively put forward. The paper ends with a discussion of how such microporous fuels could be used in the building of ''chemonuclear '' reactors. A brief study of some possible solutions shows what difficulties are still to be overcome. (author)

  1. Fast neutron induced fission of Np-237: mass spectra at high kinetic energies

    International Nuclear Information System (INIS)

    The results of measurements of the cold fragmentation mass spectra in neutron induced fission of Np-237 are discussed. The investigation of the cold fragmentation region of neptunium is needed in detail in order to understand the relationship between mass and charge subsystems inside the nucleus during all stage of a descent of the two-center figure from the fission barrier to the scission point. The twin gridded ionization chamber and data acquisition system used for the measurements are described. The fine structure of mass distributions which can be attributed to the role and behaviour of unpairing proton in neptunium is revealed. The conclusion is made that in comparison with any even-even compound system one proton in neptunium is free and can in principle join heavy fragment coming from light fragment. This effect is not specific property of the standard-I mass channel centered around magic fragment with mass m = 134 amu. Practically the same is observed for completely another channel: m = 152. It is very probable that the standard-II channel has the same properties

  2. Fission fragment driven neutron source

    Science.gov (United States)

    Miller, Lowell G.; Young, Robert C.; Brugger, Robert M.

    1976-01-01

    Fissionable uranium formed into a foil is bombarded with thermal neutrons in the presence of deuterium-tritium gas. The resulting fission fragments impart energy to accelerate deuterium and tritium particles which in turn provide approximately 14 MeV neutrons by the reactions t(d,n).sup.4 He and d(t,n).sup.4 He.

  3. Fission Dynamics of Compound Nuclei

    OpenAIRE

    Iwata, Yoritaka; Heinz, Sophia

    2012-01-01

    Collisions between $^{248}$Cm and $^{48}$Ca are systematically investigated by time-dependent density functional calculations with evaporation prescription. Depending on the incident energy and impact parameter, fusion, deep-inelastic and quasi-fission events are expected to appear. In this paper, possible fission dynamics of compound nuclei is presented.

  4. Advanced Materials in Support of EERE Needs to Advance Clean Energy Technologies Program Implementation

    Energy Technology Data Exchange (ETDEWEB)

    Liby, Alan L [ORNL; Rogers, Hiram [ORNL

    2013-10-01

    The goal of this activity was to carry out program implementation and technical projects in support of the ARRA-funded Advanced Materials in Support of EERE Needs to Advance Clean Energy Technologies Program of the DOE Advanced Manufacturing Office (AMO) (formerly the Industrial Technologies Program (ITP)). The work was organized into eight projects in four materials areas: strategic materials, structural materials, energy storage and production materials, and advanced/field/transient processing. Strategic materials included work on titanium, magnesium and carbon fiber. Structural materials included work on alumina forming austentic (AFA) and CF8C-Plus steels. The advanced batteries and production materials projects included work on advanced batteries and photovoltaic devices. Advanced/field/transient processing included work on magnetic field processing. Details of the work in the eight projects are available in the project final reports which have been previously submitted.

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

    International Nuclear Information System (INIS)

    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 229Th and 252Cf radioactive decay sources. For commissioning, the fully assembled system measured fission products from spontaneous fission of 252Cf. 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 252Cf spontaneous fission products are reported from an E–v measurement

  6. 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.

  7. Investigation of the fission fragment properties of the reaction 238U(n,f) at incident neutron energies up to 5.8 MeV

    International Nuclear Information System (INIS)

    The fission fragment properties of the reaction 238U(n,f) have been studied, at different incident neutron energies ranging from En=1.2 to 5.8 MeV. The pre-neutron emission mass, kinetic energy and fission fragment angular distributions have been investigated with a double Frisch-gridded ionization chamber. The influence of the subthreshold vibrational resonances and of the proton pairing effect on the fission fragment properties is clearly visible. The total kinetic energy averaged over all fission fragment masses TKEbar shows an increasing trend up to En=3.5 MeV with a sudden drop at roughly En=3.8 MeV which has been attributed to the onset of pair breaking at the barrier. Above En=3.8 MeV, the TKEbar is again continuously increasing. The changes in the mass yield and TKEbar(A) distributions have been studied as a function of the compound nuclear excitation energy and their contribution to the observed variations in the TKEbar have been determined. The two-dimensional mass-TKE distributions have been described in terms of fission modes and compared with theoretical calculations performed recently in the frame of the multi-modal random neck-rupture model. Although theoretically six asymmetric fission modes are predicted which all surpass individual outer barriers, an interpretation in terms of only two asymmetric modes has physical meaning. This points to an influence of shell structure effects to the observed distributions. In any case, the super-long symmetric mode has to be included, in order to explain the dip in TKEbar(A) distribution close to symmetry

  8. Investigation of the fission fragment properties of the reaction 238U(n,f) at incident neutron energies up to 5.8 MeV

    Science.gov (United States)

    Vivès, F.; Hambsch, F.-J.; Bax, H.; Oberstedt, S.

    2000-01-01

    The fission fragment properties of the reaction 238U(n,f) have been studied, at different incident neutron energies ranging from En=1.2 to 5.8 MeV. The pre-neutron emission mass, kinetic energy and fission fragment angular distributions have been investigated with a double Frisch-gridded ionization chamber. The influence of the subthreshold vibrational resonances and of the proton pairing effect on the fission fragment properties is clearly visible. The total kinetic energy averaged over all fission fragment masses ( overlineTKE) shows an increasing trend up to En=3.5 MeV with a sudden drop at roughly En=3.8 MeV which has been attributed to the onset of pair breaking at the barrier. Above En=3.8 MeV, the overlineTKE is again continuously increasing. The changes in the mass yield and overlineTKE( A) distributions have been studied as a function of the compound nuclear excitation energy and their contribution to the observed variations in the overlineTKE have been determined. The two-dimensional mass-TKE distributions have been described in terms of fission modes and compared with theoretical calculations performed recently in the frame of the multi-modal random neck-rupture model. Although theoretically six asymmetric fission modes are predicted which all surpass individual outer barriers, an interpretation in terms of only two asymmetric modes has physical meaning. This points to an influence of shell structure effects to the observed distributions. In any case, the super-long symmetric mode has to be included, in order to explain the dip in overlineTKE( A) distribution close to symmetry.

  9. Isoscaling of the Fission Fragments with Langevin Equation

    Institute of Scientific and Technical Information of China (English)

    WANG Kun; TIAN Wen-Dong; ZHONG Chen; ZHOU Xing-Fei; MA Yu-Gang; WEI Yi-Bin; CAI Xiang-Zhou; CHEN Jin-Gen; FANG De-Qing; GUO Wei; MA Guo-Liang; SHEN Wen-Qing

    2005-01-01

    @@ The Langevin equation is used to simulate the fission process of 112Sn + 112Sn and 116Sn + 116Sn. The mass distribution of the fission fragments are given by assuming the process of symmetric fission or asymmetric fission with the Gaussian probability sampling. The isoscaling behaviour has been observed from the analysis of fission fragments of both the reactions, and the isoscaling parameter α seems to be sensitive to the width of fission probability and the beam energy.

  10. Isoscaling of the Fission Fragments with Langevin Equation

    OpenAIRE

    Wang, K.; Ma, Y. G.; Wei, Y. B.; Cai, X. Z.; Chen, J. G.; Fang, D Q; Guo, W; Ma, G. L.; Shen, W.Q.(Shanghai Institute of Applied Physics, Shanghai, 201800, China); Tian, W.D.; Zhong, C.; Zhou, X. F.

    2004-01-01

    Langevin equation is used to simulate the fission process of $^{112}$Sn + $^{112}$Sn and $^{116}$Sn + $^{116}$Sn. The mass distribution of the fission fragments are given by assuming the process of symmetric fission or asymmetric fission with the Gaussian probability sampling. Isoscaling behavior has been observed from the analysis of fission fragments of both reactions and the isoscaling parameter $\\alpha$ seems to be sensitive to the width of fission probability and the beam energy.

  11. Experimental Neutron-Induced Fission Fragment Mass Yields of 232Th and 238U at Energies from 10 to 33 MeV

    CERN Document Server

    Simutkin, V D; Blomgren, J; Österlund, M; Bevilacqua, R; Ryzhov, I V; Tutin, G A; Yavshits, S G; Vaishnene, L A; Onegin, M S; Meulders, J P; Prieels, R

    2013-01-01

    Development of nuclear energy applications requires data for neutron-induced reactions for actinides in a wide neutron energy range. Here we describe measurements of pre-neutron emission fission fragment mass yields of 232Th and 238U at incident neutron energies from 10 to 33 MeV. The measurements were done at the quasi-monoenergetic neutron beam of the Louvain-la-Neuve cyclotron facility CYCLONE; a multi-section twin Frisch-gridded ionization chamber was used to detect fission fragments. For the peak neutron energies at 33, 45 and 60 MeV, the details of the data analysis and the experimental results have been published before and in this work we present data analysis in the low-energy tail of the neutron energy spectra. The preliminary measurement results are compared with available experimental data and theoretical predictions.

  12. Fission product and chemical energy releases during core melt events in U-Al research reactors

    International Nuclear Information System (INIS)

    Fission product releases data from heated uranium-aluminum reactor fuels are analyzed. Extensive library of correlations was developed for predicting releases which may vary with time, burnup ambient, fuel-type subject to certain assumptions. Correlations were developed in various forms for U-Al. (dispersed/alloy), U308-Al (dispersed) and dispersed U3Si2-AL, and U3Si-Al Fuels. Overall statistics is quite favorable. Unresolved issues and data needs demand best estimate analyses of reactors using U3Si2-Al fuel. Importance of capturing fragment size distribution was demonstrated. Results agree with Nelson's observations for onset ignition. The need to develop an appropriate fragmentation model was evident

  13. 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.

  14. Fission yield measurements at IGISOL

    Science.gov (United States)

    Lantz, M.; Al-Adili, A.; Gorelov, D.; Jokinen, A.; Kolhinen, V. S.; Mattera, A.; Moore, I.; Penttilä, H.; Pomp, S.; Prokofiev, A. V.; Rakopoulos, V.; Rinta-Antila, S.; Simutkin, V.; Solders, A.

    2016-06-01

    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.

  15. Advancing clean energy technology in Canada

    International Nuclear Information System (INIS)

    This paper discusses the development of clean energy technology in Canada. Energy is a major source of Canadian prosperity. Energy means more to Canada than any other industrialized country. It is the only OECD country with growing oil production. Canada is a stable and secure energy supplier and a major consumer. Promoting clean energy is a priority to make progress in multiple areas.

  16. General view on the progress in nuclear fission : a review

    OpenAIRE

    Schmidt, Karl-Heinz; Jurado, Beatriz

    2016-01-01

    An overview is given on some of the main advances in experimental methods, experimental results and theoretical models and ideas of the last years in the field of nuclear fission. New approaches extended the availability of fissioning systems for experimental studies of nuclear fission considerably and provided a full identification of all fission products in A and Z for the first time. In particular, the transition from symmetric to asymmetric fission around 226 Th and some unexpected struct...

  17. Correlation measurements of fission-fragment properties

    OpenAIRE

    Oberstedt A.; Martinez T.; Kis Z.; Karlsson J.; Hambsch F.-J.; Cano-Ott D.; Göök A.; Borcea R.; Billnert R.; Belgya T.; Oberstedt S.; Szentmiklosi L.; Takác K.

    2010-01-01

    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 energ...

  18. Superfluid fission dynamics with microscopic approaches

    CERN Document Server

    Simenel, C; Lacroix, D; Umar, A S

    2016-01-01

    Recent progresses in the description of the latter stage of nuclear fission are reported. Dynamical effects during the descent of the potential towards scission and in the formation of the fission fragments are studied with the time-dependent Hartree-Fock approach with dynamical pairing correlations at the BCS level. In particular, this approach is used to compute the final kinetic energy of the fission fragments. Comparison with experimental data on the fission of 258Fm are made.

  19. Advancing Opportunities in Renewable Energy Production

    OpenAIRE

    Vokony István; Bonda Balázs; Talamon Attila; Nagy Máté; Holló Gergő

    2015-01-01

    The organization - WEC Hungarian Young Professionals in Energy (HYPE) - in line with WEC’s (World Energy Council) visions aims for the dissemination of the principle of sustainable energy development in Hungary. The HYPE’s goals are to represent the Hungarian energy sector’s viewpoint at national, regional and international events; to introduce and evaluate the key energy issues by preparing studies; and to foster the development of future energy professionals.

  20. Bringing Advanced Computational Techniques to Energy Research

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Julie C

    2012-11-17

    Please find attached our final technical report for the BACTER Institute award. BACTER was created as a graduate and postdoctoral training program for the advancement of computational biology applied to questions of relevance to bioenergy research.

  1. Advanced nanomaterials and their applications in renewable energy

    CERN Document Server

    Liu, Jingbo Louise

    2015-01-01

    Advanced Nanomaterials and Their Applications in Renewable Energy presents timely topics related to nanomaterials' feasible synthesis and characterization, and their application in the energy fields. In addition, the book provides insights and scientific discoveries in toxicity study, with information that is easily understood by a wide audience. Advanced energy materials are important in designing materials that have greater physical, electronic, and optical properties. This book emphasizes the fundamental physics and chemistry underlying the techniques used to develop solar and fuel cell

  2. Advanced energy system with nuclear reactors as an energy source

    International Nuclear Information System (INIS)

    recovery system is also applicable to a fast reactor (FR) with a supercritical CO2 gas turbine that achieves higher cycle efficiency than conventional sodium cooled FRs with steam turbines. The FR will eliminate problems of conventional FRs related to safety, plant maintenance, and construction costs. The FR consumes efficiently trans-uranium elements (TRU) produced in light water reactors as fuel and reduce long-lived radioactive wastes or environmental loads of long term geological disposal. An Advanced Energy System (AES) with nuclear reactors as an energy source has been proposed which supply electricity and heat to cities. The AES has three objectives: 1. Save energy resources and reduce green house gas emissions, attaining total energy utilization efficiency higher than 85% through waste heat recovery and utilization. 2. Foster a recycling society that produces methane and methanol for fuel cells from waste products of cities and farms. 3. Consume TRU produced in LWRs as fuel for FRs, and reduce long-lived radioactive wastes or environmental loads of long term geological disposal. References 1. Y. Kato, T. Nitawaki and K. Fujima, 'Zero Waste Heat Release Nuclear Cogeneration System, 'Proc. 2003 Intl. Congress on Advanced Nuclear Power Plants (ICAPP'03), Cordoba, Spain, May 4-7, 2003, Paper 3313. 2. Y. Kato, T. Nitawaki and Y. Muto, 'Medium Temperature Carbon Dioxide Gas Turbine Reactor, 'Nucl. Eng. Design, 230, pp. 195-207 (2004). 3. H. N. Tran and Y. Kato, 'New 237Np Burning Strategy in a Supercritical CO2 Cooled Fast Reactor Core Attaining Zero Burnup Reactivity Loss,' Proc. American Nuclear Society's Topical Meeting on Reactor Physics (PHYSOR 2006), Vancouver, British Columbia, Canada, September 10-14, 2006

  3. Nuclear structure in cold rearrangement processes in fission and fusion

    International Nuclear Information System (INIS)

    In fission and fusion of heavy nuclei large numbers of nucleons are rearranged at a scale of excitation energy very small compared to the binding energy of the nuclei. The energies involved are less than 40 MeV at nuclear temperatures below 1.5 MeV. The shapes of the configurations in the rearrangement of a binary system into a monosystem in fusion, or vice versa in fission, change their elongations by as much as 8 fm, the radius of the monosystem. The dynamics of the reactions macroscopically described by a potential energy surface, inertia parameters, dissipation, and a collision energy is strongly modified by the nuclear structure of the participating nuclei. Experiments showing nuclear structure effects in fusion and fission of the heaviest nuclei are reviewed. The reaction kinematics and the multitude of isotopes involved are investigated by detector techniques and by recoil spectrometers. The advancement of the latter allows to find very small reaction branches in the range of 10-5 to 10-10. The experiments reveal nuclear structure effects in all stages of the rearrangement processes. These are discussed pointing to analogies in fusion and fission on the microscopic scale, notwithstanding that both processes macroscopically are irreversible. Heavy clusters, as 132Sn, 208Pb, nuclei with closed shell configurations N=82,126, Z=50,82 survive in large parts of the nuclear rearrangement. They determine the asymmetry in the mass distribution of low energy fission, and they allow to synthesise superheavy elements, until now up to element 112. Experiments on the cold rearrangement in fission and fusion are presented. Here, in the range of excitation energies below 12 MeV the phenomena are observed most convincingly. (orig.)

  4. Nuclear structure in cold rearrangement processes in fission and fusion

    Energy Technology Data Exchange (ETDEWEB)

    Armbruster, P.

    1998-11-01

    In fission and fusion of heavy nuclei large numbers of nucleons are rearranged at a scale of excitation energy very small compared to the binding energy of the nuclei. The energies involved are less than 40 MeV at nuclear temperatures below 1.5 MeV. The shapes of the configurations in the rearrangement of a binary system into a monosystem in fusion, or vice versa in fission, change their elongations by as much as 8 fm, the radius of the monosystem. The dynamics of the reactions macroscopically described by a potential energy surface, inertia parameters, dissipation, and a collision energy is strongly modified by the nuclear structure of the participating nuclei. Experiments showing nuclear structure effects in fusion and fission of the heaviest nuclei are reviewed. The reaction kinematics and the multitude of isotopes involved are investigated by detector techniques and by recoil spectrometers. The advancement of the latter allows to find very small reaction branches in the range of 10{sup -5} to 10{sup -10}. The experiments reveal nuclear structure effects in all stages of the rearrangement processes. These are discussed pointing to analogies in fusion and fission on the microscopic scale, notwithstanding that both processes macroscopically are irreversible. Heavy clusters, as 132Sn, 208Pb, nuclei with closed shell configurations N=82,126, Z=50,82 survive in large parts of the nuclear rearrangement. They determine the asymmetry in the mass distribution of low energy fission, and they allow to synthesise superheavy elements, until now up to element 112. Experiments on the cold rearrangement in fission and fusion are presented. Here, in the range of excitation energies below 12 MeV the phenomena are observed most convincingly. (orig.)

  5. Characteristics of Coulomb fission

    OpenAIRE

    Oberacker, Volker; Greiner, Walter; Kruse, Hans; Pinkston, William T.

    2006-01-01

    Within an extended semiquantal theory we perform large-sized coupled-channel calculations involving 260 collective levels for Coulomb fission of 238U. Differential Coulomb fission cross sections are studied as a function of bombarding energy and impact parameter for several projectiles. In the Xe + U case, total cross sections are also given. We find a strong dependence on projectile charge number, PCF(180°)∼(Zp)6 in the region 50≤Zp≤92 for a fixed ratio E/ECoul, which might...

  6. Neutron-induced fission cross-section of 233U in the energy range 0.5n< 20 MeV

    International Nuclear Information System (INIS)

    The neutron-induced fission cross-section of 233U has been measured at the CERN n-TOF facility relative to the standard fission cross-section of 235U between 0.5 and 20MeV. The experiment was performed with a fast ionization chamber for the detection of the fission fragments and to discriminate against α -particles from the natural radioactivity of the samples. The high instantaneous flux and the low background of the n-TOF facility result in data with uncertainties of ∼ 3%, which were found in good agreement with previous experiments. The high quality of the present results allows to improve the evaluation of the 233U (n,f) cross-section and, consequently, the design of energy systems based on the Th/U cycle. (orig.)

  7. Neutron-Induced Fission Cross Sections of Nuclei in the Vicinity of 208Pb at Incident Energies below 60 MeV

    Science.gov (United States)

    Ryzhov, Igor V.; Tutin, Gennady A.; Eismont, Vilen P.; Mitryukhin, Andrey G.; Oplavin, Valery S.; Soloviev, Sergey M.; Meulders, Jean-Pierre; El Masri, Youssef; Keutgen, Thomas; Prieels, René; Nolte, Ralf

    2005-05-01

    Neutron-induced fission cross sections of 205Tl, 204, 206, 207, 208Pb, and 209Bi have been measured at incident energies of 32.8, 45.3, and 59.9 MeV. The measurements were performed at the Louvain-la-Neuve neutron beam facility using the 7Li (p, n) reaction as neutron source. Fission fragments were detected with a multi-section Frisch-gridded ionization chamber (MFGIC). Neutron fluence measurements were based on the 238U(n, f) reaction. The neutron fluence monitoring procedure was asserted by crosscheck measurement, in which the 59.9-MeV neutron beam fluence was simultaneously determined with the MFGIC and with a fission chamber monitor calibrated relative to a proton-recoil telescope.

  8. Neutron-Induced Fission Cross Sections of Nuclei in the Vicinity of 208Pb at Incident Energies below 60 MeV

    International Nuclear Information System (INIS)

    Neutron-induced fission cross sections of 205Tl, 204, 206, 207, 208Pb, and 209Bi have been measured at incident energies of 32.8, 45.3, and 59.9 MeV. The measurements were performed at the Louvain-la-Neuve neutron beam facility using the 7Li (p, n) reaction as neutron source. Fission fragments were detected with a multi-section Frisch-gridded ionization chamber (MFGIC). Neutron fluence measurements were based on the 238U(n, f) reaction. The neutron fluence monitoring procedure was asserted by crosscheck measurement, in which the 59.9-MeV neutron beam fluence was simultaneously determined with the MFGIC and with a fission chamber monitor calibrated relative to a proton-recoil telescope

  9. Neutron-induced fission cross-section of {sup 233}U in the energy range 0.5

    Energy Technology Data Exchange (ETDEWEB)

    Belloni, F.; Milazzo, P.M.; Abbondanno, U.; Fujii, K.; Moreau, C. [Istituto Nazionale di Fisica Nucleare (INFN), Trieste (Italy); Calviani, M. [Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare (INFN), Legnaro (Italy); CERN, Geneva (Switzerland); Colonna, N.; Marrone, S.; Meaze, M.H.; Tagliente, G.; Terlizzi, R. [Istituto Nazionale di Fisica Nucleare (INFN), Bari (Italy); Mastinu, P.; Gramegna, F. [Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare, Legnaro (Italy); Aerts, G.; Andriamonje, S.; Berthoumieux, E.; Dridi, W.; Gunsing, F.; Pancin, J.; Perrot, L.; Plukis, A. [CEA, Irfu, Gif-sur-Yvette (France); Alvarez, H.; Cano-Ott, D.; Duran, I.; Embid-Segura, M.; Gonzalez-Romero, E.; Paradela, C. [Univ. de Santiago de Compostela, Santiago (Spain); Alvarez-Velarde, F.; Guerrero, C.; Martinez, T.; Villamarin, D.; Vincente, M.C. [Centro de Investigaciones Energeticas Medioambientales y Technologicas, Madrid (Spain); Andrzejewski, J.; Marganiec, J. [Univ. of Lodz, Lodz (Poland); Audouin, L.; Dillmann, I.; Heil, M.; Kaeppeler, F.; Mosconi, M.; Plag, R.; Voss, F.; Walter, S.; Wisshak, K. [Inst. fuer Kernphysik, Karlsruhe Inst. of Technology, Campus Nord, Karlsruhe (Germany); Badurek, G.; Jericha, E.; Leeb, H.; Oberhummer, H.; Pigni, M.T. [Technische Univ. Wien, Atominstitut der Oesterreichischen Univ., Wien (Austria); Baumann, P.; David, S.; Kerveno, M.; Lukic, S.; Rudolf, G. [Centre National de la Recherche Scientifique/IN2P3 - IReS, Strasbourg (France); Becvar, F.; Krticka, M. [Charles Univ., Faculty of Mathematics and Physics, Prague (Czech Republic); Calvino, F.; Cortes, G.; Poch, A.; Pretel, C. [Univ. Politecnica de Catalunya, Barcelona (Spain); Capote, R. [NAPC/Nuclear Data Section, International Atomic Energy Agency, Vienna (Austria); Univ. de Sevilla, Sevilla (Spain); Carrapico, C.; Goncalves, I.; Salgado, J.; Santos, C.; Tavora, L.; Vaz, P. [Inst. Tecnologico e Nuclear, Lisbon (Portugal)] [and others

    2011-01-15

    The neutron-induced fission cross-section of {sup 233}U has been measured at the CERN n-TOF facility relative to the standard fission cross-section of {sup 235}U between 0.5 and 20MeV. The experiment was performed with a fast ionization chamber for the detection of the fission fragments and to discriminate against {alpha} -particles from the natural radioactivity of the samples. The high instantaneous flux and the low background of the n-TOF facility result in data with uncertainties of {approx} 3%, which were found in good agreement with previous experiments. The high quality of the present results allows to improve the evaluation of the {sup 233}U (n,f) cross-section and, consequently, the design of energy systems based on the Th/U cycle. (orig.)

  10. Neutron emission effects on fragment mass and kinetic energy distribution from fission of 239Pu induced by thermal neutrons

    International Nuclear Information System (INIS)

    The average of fragment kinetic energy () and the multiplicity of prompt neutrons (ν(bar sign)) as a function of fragment mass (m*), as well as the fragment mass yield (Y (m*)) from thermal neutron induced fission of 239Pu, have been measured by Tsuchiya et al.. In that work the mass and kinetic energy are calculated from the measured kinetic energy of one fragment and the difference of time of flight of the two complementary fragments. However they do not present their results about the standard deviation σE*(m*). In this work we have made a numerical simulation of that experiment, assuming an initial distribution of the primary fragment kinetic energy (E(A)) with a constant value of the standard deviation as function of fragment mass σE(A)). As a result of that simulation we obtain the dependence σE*(m*) which presents an enhancement between m* = 92 and m* 110, and a peak at m* = 121. (orig.)

  11. Neutron emission effects on fragment mass and kinetic energy distribution from fission of 239Pu induced by thermal neutrons

    International Nuclear Information System (INIS)

    The average of fragment kinetic energy (E-bar sign*) and the multiplicity of prompt neutrons (ν(bar sign)) as a function of fragment mass (m*), as well as the fragment mass yield (Y(m*)) from thermal neutron-induced fission of 239Pu have been measured by Tsuchiya et al.. In that work the mass and kinetic energy are calculated from the measured kinetic energy of one fragment and the difference of time of flight of the two complementary fragments. However they do not present their results about the standard deviation σE*(m*). In this work we have made a numerical simulation of that experiment which reproduces its results, assuming an initial distribution of the primary fragment kinetic energy (E(A)) with a constant value of the standard deviation as function of fragment mass (σE(A)). As a result of the simulation we obtain the dependence σE*(m*) which presents an enhancement between m* = 92 and m* = 110, and a peak at m* = 121.

  12. Spontaneous fission. A many-body approach

    Energy Technology Data Exchange (ETDEWEB)

    Iwamoto, Akira; Bonasera, A. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    We propose new model to calculate the fission phenomena in tunnel region. By the Vlasov equation and the imaginary time method, we could calculate actinides nuclear fission. This method makes possible to describe unified the motion of fission inside and outside of potential wall. The potential energy and mass parameters can be calculated by no means of the special model. The freedom of internal motion are calculated automatically both collective and a particle motion. Accordingly, particle released during fission process can be calculated. The kinetic energy of fragment after fission was very agreeable with the calculation results. (S.Y.)

  13. 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

    crewed expedition mission. Unlike the demonstration mission, a lengthy power outage due to the global dust storms that are known to occur on Mars would pose a safety hazard to a crewed mission. A similar fission versus solar power trade study performed by NASA in 2007 concluded that fission power was more reliable-with a much lower mass penalty-than solar power for this application. However, recent advances in solar cell and energy storage technologies and changes in operational assumptions prompted NASA to revisit the analysis. For the purpose of this exercise a particular landing site at Jezero Crater, located at 18o north latitude, was assumed. A fission power system consisting of four each 10 kW Kilopower fission reactors was compared to a distributed network of Orion-derived Ultraflex solar arrays and Lithium ion batteries mounted on every lander. The team found that a solar power system mass of about 9,800 kg would provide the 22 kilowatts (kW) keep-alive power needed to survive a dust storm lasting up to 120-days at average optical depth of 5, and 35 kW peak power for normal operations under clear skies. Although this is less than half the mass estimated during the 2007 work (which assumed latitudes up to 30o) it is still more than the 7,000 kg mass of the fission system which provides full power regardless of dust storm conditions.

  14. Advanced DC/AC inverters applications in renewable energy

    CERN Document Server

    Luo, Fang Lin

    2013-01-01

    DC/AC inversion technology is of vital importance for industrial applications, including electrical vehicles and renewable energy systems, which require a large number of inverters. In recent years, inversion technology has developed rapidly, with new topologies improving the power factor and increasing power efficiency. Proposing many novel approaches, Advanced DC/AC Inverters: Applications in Renewable Energy describes advanced DC/AC inverters that can be used for renewable energy systems. The book introduces more than 100 topologies of advanced inverters originally developed by the authors,

  15. Fission fragment mass, kinetic energy and angular distribution for 235U(n,f) in the neutron energy range from thermal to 6 MeV

    International Nuclear Information System (INIS)

    A double Frisch gridded ionization chamber has been used for the measurements. For both fission fragments the mass, kinetic energy and emission angle is found. Data have been measured at different neutron energies, Esub(n), ranging from thermal to 6.0 MeV in steps of 0.5 MeV. The measured angular anisotropies will be shown. A fit, based on statistical theory, to earlier measurements of negative anisotropies for Esub(n)<=0.2 MeV will be discussed.The measured total kinetic energy averaged over all fragment masses, TKE-bar(Esub(n)), shows a sudden decrease at Esub(n)approx. 4.5 MeV in agreement with earlier measurements. This sudden decrease can not be explained by the measured change in the mass distribution. The present data of TKE-bar(Esub(n)) as function of mass-split reveal that TKE-bar(Esub(n)) decreases with Esub(n) for mass splits around the 104/132 split as predicted by calculations of B.D. Wilkins et al. It is also seen that TKE-bar(Esub(n)) increases with Esub(n) for the symmetric and the extreme asymmetric fissions. The very structured mass distribution from approximately cold fragmentation will be presented. (author)

  16. Interstellar rendezvous missions employing fission propulsion systems

    Science.gov (United States)

    Lenard, Roger X.; Lipinski, Ronald J.

    2000-01-01

    There has been a conventionally held nostrum that fission system specific power and energy content is insufficient to provide the requisite high accelerations and velocities to enable interstellar rendezvous missions within a reasonable fraction of a human lifetime. As a consequence, all forms of alternative mechanisms that are not yet, and may never be technologically feasible, have been proposed, including laser light sails, fusion and antimatter propulsion systems. In previous efforts, [Lenard and Lipinski, 1999] the authors developed an architecture that employs fission power to propel two different concepts: one, an unmanned probe, the other a crewed vehicle to Alpha Centauri within mission times of 47 to 60 years. The first portion of this paper discusses employing a variant of the ``Forward Resupply Runway'' utilizing fission systems to enable both high accelerations and high final velocities necessary for this type of travel. The authors argue that such an architecture, while expensive, is considerably less expensive and technologically risky than other technologically advanced concepts, and, further, provides the ability to explore near-Earth stellar systems out to distances of 8 light years or so. This enables the ability to establish independent human societies which can later expand the domain of human exploration in roughly eight light-year increments even presuming that no further physics or technology breakthroughs or advances occur. In the second portion of the paper, a technology requirement assessment is performed. The authors argue that reasonable to extensive extensions to known technology could enable this revolutionary capability. .

  17. A contribution to the study of mass-kinetic energy-nuclear charges correlations for fission fragments with the 'Cosi Fan Tutte' spectrometer

    International Nuclear Information System (INIS)

    The present work is devoted to the fragments produced in the neutrons induced fission of 235U, performed with the time of flight-energy spectrometer 'Cosi Fan Tutte' recently built at the neutron high flux reactor of the Laue-Langevin Institute at Grenoble. Mass-kinetic energy-nuclear charge correlations were measured for the light fission fragment group. Nuclear charges were identified for the first time on this spectrometer using the range difference of the fission fragments in an axial field ionisation chamber. The present results are in good agreement with the previous one obtained using the spectrometer 'Lohengrin', which proves the validity of the methods which we developed. In addition, we extend the measurements to higher kinetic energies. The structures which appear in the distributions are attributed to spherical and deformed shell effects in the nascent fragments and to even odd effects. The study of thermal neutron induced fission of 229Th, which is scarcely known, has been started. (author)

  18. Measurements of the ratio fo 239Pu and 235U fission cross sections in the 0.024-7.4 MeV neutron energy range

    International Nuclear Information System (INIS)

    Aimed at improving the accuracy of available nuclear data 239Pu-to-235U fission cross section ratios were measured in a broad range of neutron energies. The measurements were taken in electrostatic accelerators with the Li(p,n)-,T(p,n)- and D(d,n) reactions used as neutron sources. The fission fragments were registered by a twin ionization chamber. The measured energy dependence curve of the fission cross section ratios was calibrated by means of an auxiliary technique employing glass detectors. The quantity ratio of the fissioning nuclei in 239Pu- and 235U layers was determined by two independent methods: from the alpha-activity in the layers and by taking measurements in the reactor thermal column. The total errors in the measured results makes up 1.4 to 1.5% for the most portion of the investigated neutron energy range, while rowing up to 1.7 to 2% in the range below 100 keV

  19. Renewable energy systems advanced conversion technologies and applications

    CERN Document Server

    Luo, Fang Lin

    2012-01-01

    Energy conversion techniques are key in power electronics and even more so in renewable energy source systems, which require a large number of converters. Renewable Energy Systems: Advanced Conversion Technologies and Applications describes advanced conversion technologies and provides design examples of converters and inverters for renewable energy systems-including wind turbine and solar panel energy systems. Learn Cutting-Edge Techniques for Converters and Inverters Setting the scene, the book begins with a review of the basics of astronomy and Earth physics. It then systematically introduc

  20. Advanced research in solar-energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Luft, W.

    1983-01-01

    The Solar Energy Storage Program at the Solar Energy Research Institute is reviewed. The program provides research, systems analyses, and economic assessments of thermal and thermochemical energy storage and transport. Current activities include experimental research into very high temperature (above 800/sup 0/C) thermal energy storage and assessment of novel thermochemical energy storage and transport systems. The applications for such high-temperature storage are thermochemical processes, solar thermal-electric power generation, cogeneration of heat and electricity, industrial process heat, and thermally regenerative electrochemical systems. The research results for five high-temperature thermal energy storage technologies and two thermochemical systems are described.

  1. Ideological Fission

    DEFF Research Database (Denmark)

    Christiansen, Steen Ledet

    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...

  2. Comments About the Partition of Excitation Energy Between Complementary Fission Fragments in Connection with 'A Chairman's Note' of T. Ohsawa

    International Nuclear Information System (INIS)

    The very interesting Chairman's Note of Mr. T. Ohsawa regarding the question of excitation energy partition pushed me to write some comments about this theme that maybe can give 'much food for thoughts'. Regarding the energy sorting mechanism proposed by K-H.Schmidt and B.Jurado, affirming that the nascent fragments cannot share the same temperature at scission. P.Talou and co-workers have written: this 'stems from one assumption and one observation: i) it is assumed that the nascent fragments near scission are already in their equilibrated ground- state shape and ii) a formula for the temperature of the fragments is inferred from observed level densities. The assumption of a constant temperature formula is best suited to low excitation energies and is part of the Gilbert-Cameron level density composite representation. However, the distribution of excitation energies in the fission fragments extends to higher energies for which the Fermi-gas formula might be a better representation, as it was considered by a great part of physicists, for instance research groups from Dresda (A.Ruben et al), Los Alamos (P.Talou et al.), CEA-Cadarache (O.Serot and O.Litaize), Bucharest (A.Tudora et al.) and so on. Concerning the energy sorting mechanism, as T.Ohsawa mentioned, K-H Schmidt discussed, on the base of Egidy's formula: T =A-2/3 (17.45-0.515S+0.51S2 that the temperature of heavy fragments (HF) is lower than that of light fragments (LF) unless the shell effect S is large, which can explain the behaviour of experimental ν(A) of Naqvi et al. at 0.8 MeV and 5.5 MeV, the increase in νtot is totally accounted for only by νH.' This experimental fact is 'interpreted by energy sorting in a superfluid system due to temperature difference TL>TH

  3. Competition between fusion-fission and quasifission processes in the 32S+184W reaction

    International Nuclear Information System (INIS)

    The angular distributions of fission fragments for the 32S+184W reaction at center-of-mass energies of 118.8, 123.1, 127.3, 131.5, 135.8, 141.1, and 144.4 MeV are measured. The experimental fission excitation function is obtained. The anisotropy (Aexp) is found by extrapolating each fission fragment angular distribution. The measured fission cross sections of the 32S+182,184W reaction are decomposed into fusion-fission, quasifission, and fast-fission contributions by the dinuclear system model (DNS). The angular momentum distributions of the dinuclear system and compound nucleus calculated by the DNS model are used to reproduce the experimental capture and fusion excitation functions for both reactions and quantities K02, 2>, and Aexp, which characterize angular distributions of the fission products at the considered range of beam energy. The total evaporation residue excitation function for the 32S+184W reaction calculated in the framework of the advanced statistical model is close to the available experimental data only up to about Ec.m.≅160 MeV. The underestimation of the experimental data at high excitation energies Ec.m.>160 MeV is explained by the fact that the statistical model cannot reproduce the cross section of evaporation residues formed by the nonequilibrium mechanism, that is, without formation of the compound nucleus in the statistical equilibrium state.

  4. “Recent Advances in Energy Research”

    OpenAIRE

    Miguel, A.F.; Reis, A. Heitor

    2008-01-01

    The worldwide scarcity of fossil fuels regarding primary energy demand together with growing environmental concerns have raised new challenges to the world economy, and led to changes in the energy paradigm. Industry, services, researchers, and the Academy are challenged to envisage new solutions through setting up new conversion processes, designing new power systems, and investigating and developing new energy sources and vectors.

  5. Advanced Energy Projects: FY 1993, Research summaries

    Energy Technology Data Exchange (ETDEWEB)

    1993-09-01

    AEP has been supporting research on novel materials for energy technology, renewable and biodegradable materials, new uses for scientific discoveries, alternate pathways to energy efficiency, alternative energy sources, innovative approaches to waste treatment and reduction, etc. The summaries are grouped according to projects active in FY 1993, Phase I SBIR projects, and Phase II SBIR projects. Investigator and institutional indexes are included.

  6. Development of High-Temperature Ferritic Alloys and Performance Prediction Methods for Advanced Fission Energy Systems

    Energy Technology Data Exchange (ETDEWEB)

    G. RObert Odette; Takuya Yamamoto

    2009-08-14

    Reports the results of a comprehensive development and analysis of a database on irradiation hardening and embrittlement of tempered martensitic steels (TMS). Alloy specific quantitative semi-empirical models were derived for the dpa dose, irradiation temperature (ti) and test (Tt) temperature of yield stress hardening (or softening) .

  7. General Description of Fission Observables: GEF Model Code

    OpenAIRE

    Schmidt, Karl-Heinz; Jurado, Beatriz; Amouroux, Charlotte; Schmitt, C.

    2015-01-01

    The GEF (" GEneral description of Fission observables ") model code is documented. It describes the observables for spontaneous fission, neutron-induced fission and, more generally, for fission of a compound nucleus from any other entrance channel, with given excitation energy and angular momentum. The GEF model is applicable for a wide range of isotopes from Z = 80 to Z = 112 and beyond, up to excitation energies of about 100 MeV. The results of the GEF model are compared with fission barrie...

  8. Variation of Kinetic Energy of Fragments in Fission of 235U with 0.006 - 20ev Neutrons

    International Nuclear Information System (INIS)

    Utilizing the LNF ONYal neutron spectrometer working in the energy range between 0.006 and 20 eV, the variation in fragments' kinetic energy (EK) was studied, applying the method of relative yields (W) measurements, in the thermal neutron region and at 11 resonances of 235U. It was found that the resonances at 0.29, 2.04, 3.14, 4.84, and 7.09 eV can be sorted in a group of resonances with small values of W and EK . The resonances at 1.14, 3.60, 6.40, 8.78, 12.4, and 19.3 eV form a group with big values of W and EK. Comparison of W with radiochemical data on fragments' yield at thermal and resonance region of 235U showed that EK is larger at more asymmetrical fission. From the values W ( I ) and W(II) for the two groups of resonances, the change in the average kinetic energy of fragments 2ΔEK = 0.74 ± 0. 32 MeV was determined. (author)

  9. Advanced Energy Harvesting Control Schemes for Marine Renewable Energy Devices

    Energy Technology Data Exchange (ETDEWEB)

    McEntee, Jarlath [Ocean Renewable Power Company, Portland, ME (United States); Polagye, Brian [Ocean Renewable Power Company, Portland, ME (United States); Fabien, Brian [Ocean Renewable Power Company, Portland, ME (United States); Thomson, Jim [Ocean Renewable Power Company, Portland, ME (United States); Kilcher, Levi [Ocean Renewable Power Company, Portland, ME (United States); Marnagh, Cian [Ocean Renewable Power Company, Portland, ME (United States); Donegan, James [Ocean Renewable Power Company, Portland, ME (United States)

    2016-03-31

    The Advanced Energy Harvesting Control Schemes for Marine Renewable Energy Devices (Project) investigated, analyzed and modeled advanced turbine control schemes with the objective of increasing the energy harvested by hydrokinetic turbines in turbulent flow. Ocean Renewable Power Company (ORPC) implemented and validated a feedforward controller to increase power capture; and applied and tested the controls on ORPC’s RivGen® Power Systems in Igiugig, Alaska. Assessments of performance improvements were made for the RivGen® in the Igiugig environment and for ORPC’s TidGen® Power System in a reference tidal environment. Annualized Energy Production (AEP) and Levelized Cost of Energy (LCOE) improvements associated with implementation of the recommended control methodology were made for the TidGen® Power System in the DOE reference tidal environment. System Performance Advancement (SPA) goals were selected for the project. SPA targets were to improve Power to Weight Ratio (PWR) and system Availability, with the intention of reducing Levelized Cost of Electricity (LCOE). This project focused primarily reducing in PWR. Reductions in PWR of 25.5% were achieved. Reductions of 20.3% in LCOE were achieved. This project evaluated four types of controllers which were tested in simulation, emulation, a laboratory flume, and the field. The adaptive Kω2 controller performs similarly to the non-adaptive version of the same controller and may be useful in tidal channels where the mean velocity is continually evolving. Trends in simulation were largely verified through experiments, which also provided the opportunity to test assumptions about turbine responsiveness and control resilience to varying scales of turbulence. Laboratory experiments provided an essential stepping stone between simulation and implementation on a field-scale turbine. Experiments also demonstrated that using “energy loss” as a metric to differentiate between well-designed controllers operating at

  10. Mutlifunctional Fibers for Energy Storage in Advanced EVA Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The overall objective of the Phase II effort is to demonstrate prototype multifunctional EVA system power patches that integrate energy storage into advanced space...

  11. Fission product yields from 22 MeV neutron-induced fission of 235U

    International Nuclear Information System (INIS)

    The chain yields of 28 product nuclides were determined for the fission of 235U induced by 22 MeV neutrons for the first time. Absolute fission rate was monitored with a double-fission chamber. Fission product activities were measured by HPGe γ-ray spectrometry. Time of flight technique was used to measure the neutron spectrum in order to estimate fission events induced by break-up neutrons and scattering neutrons. A mass distribution curve was obtained and the dependence of fission yield on neutron energy is discussed

  12. Fission product yields from 19.1 MeV neutron induced fission of 238U

    International Nuclear Information System (INIS)

    36 chain yields were determined for the fission of 238U induced by 19.1 MeV neutrons for the first time. Absolute fission rate was monitored with a double-fission chamber. Fission product activities were measured by HPGe γ-ray spectrometry. Threshold detector method was used to measure the neutron spectrum in order to estimate the fission events induced by break-up neutrons and scattering neutrons. A mass distribution curve was obtained and the dependence of fission yield on neutron energy was discussed

  13. The microscopic theory of fission

    OpenAIRE

    Younes, W.; Gogny, D.

    2009-01-01

    Fission-fragment properties have been calculated for thermal neutron-induced fission on a $^{239}\\textrm{Pu}$ target, using constrained Hartree-Fock-Bogoliubov calculations with a finite-range effective interaction. A quantitative criterion based on the interaction energy between the nascent fragments is introduced to define the scission configurations. The validity of this criterion is benchmarked against experimental measurements of the kinetic energies and of multiplicities of neutrons emi...

  14. Superheavy nuclei and fission barriers

    Science.gov (United States)

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

    In this chapter, we will present relativistic mean field (RMF) description of heavy and superheavy nuclei (SHN). We will discuss the shell structure and magic numbers in the mass region of SHN, binding energies and α decay Q values, shapes of ground states and potential energy surfaces and fission barriers. We particularly focus on the multidimensionally-constrained covariant density functional theories (CDFT) and the applications of CDFT to the study of exotic nuclear shapes and fission barriers.

  15. Systematics study of the ZP model for the 235U + n fission

    International Nuclear Information System (INIS)

    The ZP model was studied to evaluate the independent fission yields for 235U induced by thermal, fission, and about 14 MeV energy neutrons. The parameters of ZP model were deduced based upon measured data, and were used to calculate the yields and their errors. The yields were compared with those from TALYS calculations, ENDF/B7-FPY, JEFF-3.0/FPY and JENDL-3.3/FPY, the result showed that the present yields as well as their errors were improved. Due to the lack of measured data, the results for fission neutrons and 14 MeV energy neutrons have larger uncertainties and discrepancies than those for thermal fission. So more measurements and advanced theories are needed

  16. Systematics study of the Z{sub P} model for the {sup 235}U + n fission

    Energy Technology Data Exchange (ETDEWEB)

    Shu, N.C.; Liu, T.J.; Yua, H.W.; Chen, Y.J. [China Institute of Atomic Energy, Beijing, P.R. (China)

    2008-07-01

    The Z{sub P} model was studied to evaluate the independent fission yields for {sup 235}U induced by thermal, fission, and about 14 MeV energy neutrons. The parameters of Z{sub P} model were deduced based upon measured data, and were used to calculate the yields and their errors. The yields were compared with those from TALYS calculations, ENDF/B7-FPY, JEFF-3.0/FPY and JENDL-3.3/FPY, the result showed that the present yields as well as their errors were improved. Due to the lack of measured data, the results for fission neutrons and 14 MeV energy neutrons have larger uncertainties and discrepancies than those for thermal fission. So more measurements and advanced theories are needed.

  17. Saving Building Energy through Advanced Control Strategies

    Directory of Open Access Journals (Sweden)

    Stephen Treado

    2013-09-01

    Full Text Available This article presents an analysis of the relationship between building energy usage and building control system operation and performance. A method is presented for estimating the energy saving potential of improvements in building and control system operation, including the relative impact of recommssioning and hardware and software upgrades, based on a subjective assessment of the level of energy efficient design and the energy usage of the building relative to similar buildings as indicated by the Energy Utilization Index for the building. The method introduces a Building Design Index and a Building Operating Index to evaluate building energy performance versus similar buildings, and uses these indices to estimate potential savings and effectiveness of control system improvements.

  18. Advanced Waste-To-Energy Cycles

    OpenAIRE

    Branchini, Lisa

    2012-01-01

    The increase in environmental and healthy concerns, combined with the possibility to exploit waste as a valuable energy resource, has led to explore alternative methods for waste final disposal. In this context, the energy conversion of Municipal Solid Waste (MSW) in Waste-To-Energy (WTE) power plant is increasing throughout Europe, both in terms of plants number and capacity, furthered by legislative directives. Due to the heterogeneous nature of waste, some differences with respect to a...

  19. Advanced energy projects; FY 1995 research summaries

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-09-01

    The AEP Division supports projects to explore novel energy-related concepts which are typically at an early stage of scientific development, and high-risk, exploratory concepts. Topical areas presently receiving support are: novel materials for energy technology, renewable and biodegradable materials, exploring uses of new scientific discoveries, alternate pathways to energy efficiency, alternative energy sources, and innovative approaches to waste treatment and reduction. There were 46 research projects during FY 1995; ten were initiated during that fiscal year. The summaries are separated into grant and laboratory programs, and small business innovation research programs.

  20. Chemical Production using Fission Fragments

    International Nuclear Information System (INIS)

    Some reactor design considerations of the use of fission recoil fragment energy for the production of chemicals of industrial importance have been discussed previously in a paper given at the Second United Nations International Conference on the Peaceful Uses of Atomic Energy [A/Conf. 15/P.76]. The present paper summarizes more recent progress made on this topic at AERE, Harwell. The range-energy relationship for fission fragments is discussed in the context of the choice of fuel system for a chemical production reactor, and the experimental observation of a variation of chemical effect along the length of a fission fragment track is described for the irradiation of nitrogen-oxygen mixtures. Recent results are given on the effect of fission fragments on carbon monoxide-hydrogen gas mixtures and on water vapour. No system investigated to date shows any outstanding promise for large-scale chemical production. (author)