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1

Nuclear fission  

Science Journals Connector (OSTI)

The experimental evidence supporting the double-humped character of the fission barrier in actinide nuclei is reviewed and compared to theoretical predictions. The discussion covers the existence and half-life systematics of spontaneously fissioning isomers, shape-isomeric gamma decay, rotational transitions and the moment of inertia of isomers, fragment angular distributions in isomeric fission, intermediate structure in fission cross sections, and finally the systematics of barrier heights as deduced from fission probability measurements. The implications of a possible octupole deformation at the second barrier for fragment mass distributions are also discussed, including the size of the mass asymmetry and recent experiments on the competition between symmetric and asymmetric fission as a function of excitation energy.

Hans J. Specht

1974-10-01T23:59:59.000Z

2

Lesson 5- Fission and Chain Reactions  

Energy.gov (U.S. Department of Energy (DOE))

Lesson Four showed how the nuclei of atoms store energy and how unstable atoms decay and release energy. How do nuclear engineers use this knowledge to help them harness energy to make electricity? The answer lies in being able to start a nuclear chain reaction in fuel inside a nuclear power plant and keep it going. This lesson examines nuclear reactions called fission as well as how uranium is processed from ore to fuel.

3

Nuclear Models and Nuclear Fission  

Science Journals Connector (OSTI)

The hindrance to spontaneous fission by the odd nucleon in the fissioning nucleus may be explained as due to the pairing energy of the odd nucleon at the saddle-point deformation.

Peter Fong

1961-06-01T23:59:59.000Z

4

Density Functional Theory Approach to Nuclear Fission  

E-Print Network (OSTI)

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.

N. Schunck

2013-01-20T23:59:59.000Z

5

NUCLEAR REACTORS.  

E-Print Network (OSTI)

??Nuclear reactors are devices containing fissionable material in sufficient quantity and so arranged as to be capable of maintaining a controlled, self-sustaining NUCLEAR FISSION chain… (more)

Belachew, Dessalegn

2010-01-01T23:59:59.000Z

6

Nuclear Thermal Rockets: The Physics of the Fission Reactor  

E-Print Network (OSTI)

Nuclear Thermal Rockets: The Physics of the Fission Reactor Shane D. Ross Control and Dynamical combustion are those powered by nuclear fission. Comparison of Chemical and Nuclear Rockets. Most existent.g., hydrogen and oxygen). In a nuclear rocket, or more precisely, a nuclear thermal rocket, the propellant

Ross, Shane

7

September 2013 Most Viewed Documents for Fission And Nuclear...  

Office of Scientific and Technical Information (OSTI)

September 2013 Most Viewed Documents for Fission And Nuclear Technologies Science Subject Feed Estimation of gas leak rates through very small orifices and channels. From sealed...

8

January 2013 Most Viewed Documents for Fission And Nuclear Technologie...  

Office of Scientific and Technical Information (OSTI)

January 2013 Most Viewed Documents for Fission And Nuclear Technologies Laboratory studies of shearleach processing of zircaloy clad metallic uranium reactor fuel Swanson, J.L.;...

9

The Future of Energy from Nuclear Fission  

SciTech Connect

Nuclear energy is an important part of our current global energy system, and contributes to supplying the significant demand for electricity for many nations around the world. There are 433 commercial nuclear power reactors operating in 30 countries with an installed capacity of 367 GWe as of October 2011 (IAEA PRIS, 2011). Nuclear electricity generation totaled 2630 TWh in 2010 representing 14% the world’s electricity generation. The top five countries of total installed nuclear capacity are the US, France, Japan, Russia and South Korea at 102, 63, 45, 24, and 21 GWe, respectively (WNA, 2012a). The nuclear capacity of these five countries represents more than half, 68%, of the total global nuclear capacity. The role of nuclear power in the global energy system today has been motivated by several factors including the growing demand for electric power, the regional availability of fossil resources and energy security concerns, and the relative competitiveness of nuclear power as a source of base-load electricity. There is additional motivation for the use of nuclear power because it does not produce greenhouse gas (GHG) emissions or local air pollutants during its operation and contributes to low levels of emissions throughout the lifecycle of the nuclear energy system (Beerten, J. et. al., 2009). Energy from nuclear fission primarily in the form of electric power and potentially as a source of industrial heat could play a greater role for meeting the long-term growing demand for energy worldwide while addressing the concern for climate change from rising GHG emissions. However, the nature of nuclear fission as a tremendously compact and dense form of energy production with associated high concentrations of radioactive materials has particular and unique challenges as well as benefits. These challenges include not only the safety and cost of nuclear reactors, but proliferation concerns, safeguard and storage of nuclear materials associated with nuclear fuel cycles. In March of 2011, an unprecedented earthquake of 9 magnitude and ensuing tsunami off the east coast of Japan caused a severe nuclear accident in Fukushima, Japan (Prime Minister of Japan and His Cabinet, 2011). The severity of the nuclear accident in Japan has brought about a reinvestigation of nuclear energy policy and deployment activities for many nations around the world, most notably in Japan and Germany (BBC, 2011; Reuter, 2011). The response to the accident has been mixed and its full impact may not be realized for many years to come. The nuclear accident in Fukushima, Japan has not directly affected the significant on-going nuclear deployment activities in many countries. China, Russia, India, and South Korea, as well as others, are continuing with their deployment plans. As of October 2011, China had the most reactors under construction at 27, while Russia, India, and South Korea had 11, 6, and 5 reactors under construction, respectively (IAEA PRIS, 2011). Ten other nations have one or two reactors currently under construction. Many more reactors are planned for future deployment in China, Russia, and India, as well as in the US. Based on the World Nuclear Association’s data, the realization of China’s deployment plan implies that China will surpass the US in total nuclear capacity some time in the future.

Kim, Son H.; Taiwo, Temitope

2013-04-13T23:59:59.000Z

10

Nuclear Superfluidity and Statistical Effects in Nuclear Fission  

Science Journals Connector (OSTI)

The Bardeen, Cooper, Schrieffer formalism is applied to a calculation of the mean-square projection K02 of the angular momentum along the symmetry axis of an excited deformed nucleus. The results are compared with empirical values obtained from analysis of recent data on fission-fragment angular distributions. The comparison corroborates qualitatively the validity of this application of the BCS formalism. Quantitative optimization of the fit to experiment yields the result that the energy gap for a nucleus deformed to the fission-barrier shape is about twice as large as the same quantity at the stable shape. Implications of this result for odd-even effects in nuclear fission are discussed.

James J. Griffin

1963-12-01T23:59:59.000Z

11

June 2014 Most Viewed Documents for Fission And Nuclear Technologies...  

Office of Scientific and Technical Information (OSTI)

June 2014 Most Viewed Documents for Fission And Nuclear Technologies Behavior of spent nuclear fuel in water pool storage Johnson, A.B. Jr. (1977) 78 Estimation of gas leak rates...

12

Prompt muon-induced fission: a sensitive probe for nuclear energy dissipation and fission dynamics  

E-Print Network (OSTI)

Following the formation of an excited muonic atom, inner shell transitions may proceed without photon emission by inverse internal conversion, i.e. the muonic excitation energy is transferred to the nucleus. In actinides, the 2p -> 1s and the 3d -> 1s muonic transitions result in excitation of the nuclear giant dipole and giant quadrupole resonances, respectively, which act as doorway states for fission. The nuclear excitation energy is typically 6.5 - 10 MeV. Because the muon lifetime is long compared to the timescale of prompt nuclear fission, the motion of the muon in the Coulomb field of the fissioning nucleus may be utilized to learn about the dynamics of fission.

Volker E. Oberacker; A. Sait Umar; Feodor F. Karpeshin

2004-03-30T23:59:59.000Z

13

July 2013 Most Viewed Documents for Fission And Nuclear Technologies...  

Office of Scientific and Technical Information (OSTI)

July 2013 Most Viewed Documents for Fission And Nuclear Technologies Science Subject Feed Estimation of gas leak rates through very small orifices and channels. From sealed PuO...

14

110101BenefitsNuclearFission.ppt [Read-Only]  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Benefits of Nuclear Fission to Benefits of Nuclear Fission to the Civilian Space Program Gary Langford Fission Project Manager NASA MSFC NERAC Nov. 6, 2001 2 * Outer solar system exploration. * Planetary or lunar surface missions (robotic or human). * High-performance propulsion for human missions. * Advanced applications. Uses of Nuclear Fission in the Civilian Space Program Highly advanced propulsion, extremely high power surface applications. 3 2000 2010 2020 2030 2040 Phase 1 * 10-500 kW NEP * 10-500 kW spacecraft & surface powerplants Phase 3 * 10-1000 MW, 0.1-1 kg/kW NEP * >2000 s Isp gas/plasma-based NTR Phase 2 * 1-100 MW, 1-10 kg/kW NEP * 900-1000 s Isp solid- core NTR * Multi-MW space & surface powerplants Kuiper Belt Exploration Triton Lander Europa Ocean Science Station Pluto Orbiter Large Asteroids Io Volcanic Observer

15

Compilation of fission product yields Vallecitos Nuclear Center  

SciTech Connect

This document is the ninth in a series of compilations of fission yield data made at Vallecitos Nuclear Center in which fission yield measurements reported in the open literature and calculated charge distributions have been utilized to produce a recommended set of yields for the known fission products. The original data with reference sources, as well as the recommended yields are presented in tabular form for the fissionable nuclides U-235, Pu-239, Pu-241, and U-233 at thermal neutron energies; for U-235, U-238, Pu-239, and Th-232 at fission spectrum energies; and U-235 and U-238 at 14 MeV. In addition, U-233, U-236, Pu-240, Pu-241, Pu-242, Np-237 at fission spectrum energies; U-233, Pu-239, Th-232 at 14 MeV and Cf-252 spontaneous fission are similarly treated. For 1979 U234F, U237F, Pu249H, U234He, U236He, Pu238F, Am241F, Am243F, Np238F, and Cm242F yields were evaluated. In 1980, Th227T, Th229T, Pa231F, Am241T, Am241H, Am242Mt, Cm245T, Cf249T, Cf251T, and Es254T are also evaluated.

Rider, B.F.

1980-01-01T23:59:59.000Z

16

Two-billion-year-old nuclear reactors: Nature goes fission  

SciTech Connect

Once it was thought that the isotopic composition of natural uranium was invariant. It was thus surprising in 1972 when French scientists observed small but significant deficiencies of the minor isotope {sup 235}U in uranium ore. Subsequent investigations traced the isotopically anomalous material to the Oklo mine in the African Republic of Gabon. In the mine, cubic-dekametre-sized pods of rock were found to contain extraordinary concentrations of uranium, as much as 65%, with as little as half the normal isotopic abundance of {sup 235}U. In these rocks, neodymium was found to be deficient in the premordial isotope {sup 142}Nd and enriched in the fission-produced isotopes {sup 143-150}Nd. The presence of fission products was unambiguous evidence that the {sup 235}U deficiencies were the result of sustained nuclear fission. Within the heart of the natural reactors, the fission densities were on the order of 10{sup 20} fissions/cm{sup 3}, producing hundreds of megajoules of energy and tens of microwatts of power per gram of rock. Nature had forestalled man`s great discovery of energy production by nuclear fission.

Curtis, D.B. [Los Alamos National Lab., NM (US)

1992-12-31T23:59:59.000Z

17

Planetary and Protostellar Nuclear Fission: Implications for Planetary Change, Stellar Ignition and Dark Matter  

Science Journals Connector (OSTI)

...changes in the geomagnetic field. The concept that thermonuclear fusion reactions in stars are ignited by nuclear fission...protostellar nuclear fission reactors failed to ignite thermonuclear fusion reactions. The Royal Society is collaborating...

1994-01-01T23:59:59.000Z

18

nuclear reactor  

Science Journals Connector (OSTI)

...a complex atomic apparatus used to obtain energy from nuclear fission chain reaction. Used to produce nuclear energy, radioactive isotopes, and artificial elements.... atomic pile ...

2009-01-01T23:59:59.000Z

19

Spontaneous Muon Emission during Fission, a New Nuclear Radioactivity  

E-Print Network (OSTI)

In this paper the essential theoretical predictions for the nuclear muonic radioactivity are presented by using a special fission-like model similar with that used in description of the pionic emission during fission. Hence, a fission-like model for the muonic radioactivity takes into account the essential degree of freedom of the system: muon-fissility, muon-fission barrier height, etc. Using this model it was shown that most of the SHE-nuclei lie in the region where the muonic fissility parameters attain their limiting value X=1. Hence, the SHE-region is characterized by the absence of a classical barrier toward spontaneous muon and pion emissions. Numerical estimations on the yields for the natural muonic radioactivities of the transuranium elements as well numerical values for barrier heights are given only for even-even parent nuclei. Some experimental results from LCP-identification emission spectrum are reviewed. Also, the experimental results obtained by Khryachkov et al, using new spectrometer for investigation of ternary nuclear fission, are presented. The OPERA-experiment proposed to perform search for muonic radioactivity from lead nuclei, in the low background conditions offered by the Gran Sasso underground Laboratory (LNGS), is discussed.

D. B. Ion; M. L. D. Ion; Reveica Ion-Mihai

2011-01-24T23:59:59.000Z

20

VII. Nuclear Chemistry (Chapter 17) A. Modes of radioactive decay, nuclear reactions, fission, fusion  

E-Print Network (OSTI)

40 VII. Nuclear Chemistry (Chapter 17) A. Modes of radioactive decay, nuclear reactions, fission #12;41 These masses are not exactly integer multiples due to nuclear interactions between the protons differences via the famous formula E = mc2 . Nuclear Fusion! For example, if you combine 2 protons and two

Note: This page contains sample records for the topic "nuclear fission chain" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Prescission neutron multiplicity and fission probability from Langevin dynamics of nuclear fission  

E-Print Network (OSTI)

A theoretical model of one-body nuclear friction which was developed earlier, namely the chaos-weighted wall formula, is applied to a dynamical description of compound nuclear decay in the framework of the Langevin equation coupled with statistical evaporation of light particles and photons. We have used both the usual wall formula friction and its chaos-weighted version in the Langevin equation to calculate the fission probability and prescission neutron multiplicity for the compound nuclei $^{178}$W, $^{188}$Pt, $^{200}$Pb, $^{213}$Fr, $^{224}$Th, and $^{251}$Es. We have also obtained the contributions of the presaddle and postsaddle neutrons to the total prescission multiplicity. A detailed analysis of our results leads us to conclude that the chaos-weighted wall formula friction can adequately describe the fission dynamics in the presaddle region. This friction, however, turns out to be too weak to describe the postsaddle dynamics properly. This points to the need for a suitable explanation for the enhanc...

Chaudhuri, G; Chaudhuri, Gargi; Pal, Santanu

2002-01-01T23:59:59.000Z

22

April 2013 Most Viewed Documents for Fission And Nuclear Technologies |  

Office of Scientific and Technical Information (OSTI)

April 2013 Most Viewed Documents for Fission And Nuclear Technologies April 2013 Most Viewed Documents for Fission And Nuclear Technologies Behavior of spent nuclear fuel in water pool storage Johnson, A.B. Jr. (null) 298 Estimation of gas leak rates through very small orifices and channels. [From sealed PuO/sub 2/ containers under accident conditions] Bomelburg, H.J. (null) 292 Graphite design handbook Ho, F.H. (1988) 216 System Definition and Analysis: Power Plant Design and Layout NONE (1996) 123 Flow-induced vibration of circular cylindrical structures Chen, S.S. (1985) 116 Stress analysis and evaluation of a rectangular pressure vessel. [For equipment for sampling Hanford tank radwaste] Rezvani, M.A.; Ziada, H.H. (Westinghouse Hanford Co., Richland, WA (United States)); Shurrab, M.S. (Westinghouse Savannah River Co., Aiken, SC (United

23

Detecting fission from special nuclear material sources  

DOE Patents (OSTI)

A neutron detector system for discriminating fissile material from non-fissile material wherein a digital data acquisition unit collects data at high rate, and in real-time processes large volumes of data directly into information that a first responder can use to discriminate materials. The system comprises counting neutrons from the unknown source and detecting excess grouped neutrons to identify fission in the unknown source. The system includes a graphing component that displays the plot of the neutron distribution from the unknown source over a Poisson distribution and a plot of neutrons due to background or environmental sources. The system further includes a known neutron source placed in proximity to the unknown source to actively interrogate the unknown source in order to accentuate differences in neutron emission from the unknown source from Poisson distributions and/or environmental sources.

Rowland, Mark S. (Alamo, CA); Snyderman, Neal J. (Berkeley, CA)

2012-06-05T23:59:59.000Z

24

Securing the Sustainability of Global Medical Nuclear Supply Chains  

E-Print Network (OSTI)

Securing the Sustainability of Global Medical Nuclear Supply Chains Through Economic Cost Recovery University of Massachusetts Amherst Securing the Sustainability of Medical Nuclear Supply Chains #12 of Massachusetts Amherst Securing the Sustainability of Medical Nuclear Supply Chains #12;This presentation

Nagurney, Anna

25

Low-energy nuclear fission and our understanding of the nucleus  

Science Journals Connector (OSTI)

The interactions between experimental discoveries in low-energy nuclear fission and our theoretical understanding of the ... our current experimental and theoretical understanding of low-energy fission and the pr...

H. L. Hall; D. C. Hoffman

1990-09-01T23:59:59.000Z

26

September 2013 Most Viewed Documents for Fission And Nuclear Technologies |  

Office of Scientific and Technical Information (OSTI)

Fission And Nuclear Technologies Fission And Nuclear Technologies Estimation of gas leak rates through very small orifices and channels. [From sealed PuO/sub 2/ containers under accident conditions] Bomelburg, H.J. (1977) 133 Stress analysis and evaluation of a rectangular pressure vessel. [For equipment for sampling Hanford tank radwaste] Rezvani, M.A.; Ziada, H.H. (Westinghouse Hanford Co., Richland, WA (United States)); Shurrab, M.S. (Westinghouse Savannah River Co., Aiken, SC (United States)) (1992) 78 Graphite design handbook Ho, F.H. (1988) 76 Feed-pump hydraulic performance and design improvement, Phase I: research program design. Final report Brown, W.H.; Gopalakrishnan, S.; Fehlau, R.; Thompson, W.E.; Wilson, D.G. (1982) 69 Flow-induced vibration of circular cylindrical structures Chen, S.S. (1985)

27

Enrico Fermi Achieves First Self Sustain Nuclear Chain Reaction...  

National Nuclear Security Administration (NNSA)

Self Sustain Nuclear Chain Reaction Chicago, IL Metallurgical Laboratory scientists led by Enrico Fermi achieve the first self-sustained nuclear chain reaction in pile...

28

Physics -Particle and Nuclear Physics | Theory of Nuclear Fission Springer is part of Springer Science+Business Media  

E-Print Network (OSTI)

Physics - Particle and Nuclear Physics | Theory of Nuclear Fission © Springer is part of Springer Science+Business Media Theory of Nuclear Fission A Textbook Series: Lecture Notes in Physics, Vol. 838 v arious aspects of the nuclear f ission phenomenon discov ered by Hahn, Strassmann and Meitner

Pomorski, Krzysztof

29

Nuclear Design of the HOMER-15 Mars Surface Fission Reactor  

SciTech Connect

The next generation of robotic missions to Mars will most likely require robust power sources in the range of 3 to 20 kWe. Fission systems are well suited to provide safe, reliable, and economic power within this range. The goal of this study is to design a compact, low-mass fission system that meets Mars surface power requirements, while maintaining a high level of safety and reliability at a relatively low cost. The Heat pipe Power System (HPS) is one possible approach for producing near-term, low-cost, space fission power. The goal of the HPS project is to devise an attractive space fission system that can be developed quickly and affordably. The primary ways of doing this are by using existing technology and by designing the system for inexpensive testing. If the system can be designed to allow highly prototypic testing with electrical heating, then an exhaustive test program can be carried out quickly and inexpensively, and thorough testing of the actual flight unit can be performed - which is a major benefit to reliability. Over the past 4 years, three small HPS proof-of-concept technology demonstrations have been conducted, and each has been highly successful. The Heat pipe-Operated Mars Exploration Reactor (HOMER) is a derivative of the HPS designed especially for producing power on the surface of Mars. The HOMER-15 is a 15-kWt reactor that couples with a 3-kWe Stirling engine power system. The reactor contains stainless-steel (SS)-clad uranium nitride (UN) fuel pins that are structurally and thermally bonded to SS/sodium heat pipes. Fission energy is conducted from the fuel pins to the heat pipes, which then carry the heat to the Stirling engine. This paper describes conceptual design and nuclear performance the HOMER-15 reactor. (author)

Poston, David I. [Nuclear Systems Design Group, Decision Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico, 87545 (United States)

2002-07-01T23:59:59.000Z

30

Nuclear chain reaction: forty years later  

SciTech Connect

The proceedings from a 1982 symposium 40 years after the first controlled nuclear chain reaction took place in Chicago covers four sessions and public discussion. The session covered the history of the chain reaction; peaceful uses in technology, medicine, and biological science; peaceful uses in power generation; and nuclear weapons control. Among the speakers were Eugene Wigner, Glenn Seaborg, Alvin Weinberg, and others who participated in the first chain reaction experiments. The proceedings reflect differences of opinion among the scientists as well as the general public. References, slides, and tables used to illustrate the individual talks are included with the papers.

Sachs, R.G. (ed.)

1984-01-01T23:59:59.000Z

31

Description of induced nuclear fission with Skyrme energy functionals: Static potential energy surfaces and fission fragment properties  

Science Journals Connector (OSTI)

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 density functional theory with Skyrme energy densities. Potential energy surfaces are computed at the Hartree-Fock-Bogoliubov approximation with up to five collective variables. We find that the triaxial degree of freedom plays an important role, both near the fission barrier and at scission. The impact of the parametrization of the Skyrme energy density and the role of pairing correlations on deformation properties from the ground state up to scission are also quantified. We introduce a general template for the quantitative description of fission fragment properties. It is based on the careful analysis of scission configurations, using both advanced topological methods and recently proposed quantum many-body techniques. We conclude that an accurate prediction of fission fragment properties at low incident neutron energies, although technologically demanding, should be within the reach of current nuclear density functional theory.

N. Schunck; D. Duke; H. Carr; A. Knoll

2014-11-06T23:59:59.000Z

32

Measurement/Evaluation Techniques and Nuclear Data Associated with Fission of 239Pu by Fission Spectrum Neutrons  

SciTech Connect

This Panel was chartered to review and assess new evaluations of work on fission product data, as well as the evaluation process used by the two U.S. nuclear weapons physics laboratories. The work focuses on fission product yields resulting from fission spectrum neutrons incident on plutonium, and includes data from measurements that had not been previously published as well as new or revised fission product cumulative yield data, and related quantities such as Q values and R values. This report documents the Panel's assessment of the work presented by Los Alamos National Laboratory (LANL) and Lawrence Livermore National Laboratory (LLNL). Based on the work presented we have seven key observations: (1) Experiments conducted in the 1970s at LANL, some of which were performed in association with a larger, NIST-led, program, have recently been documented. A preliminary assessment of this work, which will be referred to in this document as ILRR-LANL, shows it to be technically sound. (2) LLNL has done a thorough, unbiased review and evaluation of the available literature and is in the process of incorporating the previously unavailable LANL data into its evaluation of key fission product yields. The results of the LLNL effort, which includes a preliminary evaluation of the ILRR-LANL data, have been documented. (3) LANL has also conducted an evaluation of fission product yields for fission spectrum neutrons on plutonium including a meta-analysis of benchmark data as part of a planned upgrade to the ENDF/B compilation. We found that the approach of using meta-analysis provides valuable additional insight for evaluating the sparse data sets involved in this assessment. (4) Both laboratories have provided convincing evidence for energy dependence in the fission product yield of {sup 147}Nd produced from the bombardment of {sup 239}Pu with fission spectrum neutrons over an incident neutron energy range of 0.2 to 1.9 MeV. (5) Consistent, complete, and explicit treatment of both systematic and statistical uncertainties, including correlations, are critical to the assessment of both the experimental measurements (due to variations between experimental techniques, irradiation conditions, calibration procedures, etc.), and the evaluation of those experiments to extract fundamental nuclear data. A clear example of the importance of uncertainty analysis is in the justification for energy-dependent {sup 147}Nd fission product yield, where the magnitude of the effect is comparable to the uncertainties of the individual fission product yield measurements. Both LANL and LLNL are committed to the inclusion of full uncertainty analysis in their evaluations. (6) The Panel reviewed in detail two methods for determining/evaluating fission product yields from which fission assessments can be made: the K factor method and high-resolution gamma spectroscopy (both described more fully in Sections 3 and 4). The panel concluded that fission product yields, and thus fission assessments, derived using either approach are equally valid, provided that the data were obtained from well understood, direct fission measurements and that the key underlying calibrations and/or data are valid for each technique. (7) The Panel found the process of peer review of the two complementary but independent methods to be an extremely useful exercise. Although work is still ongoing and the numbers presented to the Panel may change slightly, both groups are now in much better agreement on not just one, but four key fission product yields. The groups also have a better appreciation of the strengths and weaknesses of each other's methods.

Baisden, P; Bauge, E; Ferguson, J; Gilliam, D; Granier, T; Jeanloz, R; McMillan, C; Robertson, D; Thompson, P; Verdon, C; Wilkerson, C; Young, P

2010-03-16T23:59:59.000Z

33

SNIF: A Futuristic Neutrino Probe for Undeclared Nuclear Fission Reactors  

E-Print Network (OSTI)

Today reactor neutrino experiments are at the cutting edge of fundamental research in particle physics. Understanding the neutrino is far from complete, but thanks to the impressive progress in this field over the last 15 years, a few research groups are seriously considering that neutrinos could be useful for society. The International Atomic Energy Agency (IAEA) works with its Member States to promote safe, secure and peaceful nuclear technologies. In a context of international tension and nuclear renaissance, neutrino detectors could help IAEA to enforce the Treaty on the Non-Proliferation of Nuclear Weapons (NPT). In this article we discuss a futuristic neutrino application to detect and localize an undeclared nuclear reactor from across borders. The SNIF (Secret Neutrino Interactions Finder) concept proposes to use a few hundred thousand tons neutrino detectors to unveil clandestine fission reactors. Beyond previous studies we provide estimates of all known background sources as a function of the detector's longitude, latitude and depth, and we discuss how they impact the detectability.

Thierry Lasserre; Maximilien Fechner; Guillaume Mention; Romain Reboulleau; Michel Cribier; Alain Letourneau; David Lhuillier

2010-11-16T23:59:59.000Z

34

Euratom Programme for Nuclear Research and Training Guide for Applicants: FP7-Fission-2007 GUIDE FOR APPLICANTS  

E-Print Network (OSTI)

Euratom Programme for Nuclear Research and Training Guide for Applicants: FP7-Fission-2007 i GUIDE FOR APPLICANTS Euratom Programme for Nuclear Research and Training Activities Call Identifier: FP7-Fission-2007 Programme for Nuclear Research and Training Guide for Applicants: FP7-Fission-2007 iii Contents TU1UT

De Cindio, Fiorella

35

Securing the Sustainability of Global Medical Nuclear Supply Chains  

E-Print Network (OSTI)

Securing the Sustainability of Global Medical Nuclear Supply Chains Through Economic Cost Recovery-17, 2012 University of Massachusetts Amherst Securing the Sustainability of Medical Nuclear Supply Chains-2013. University of Massachusetts Amherst Securing the Sustainability of Medical Nuclear Supply Chains #12;This

Nagurney, Anna

36

Mo Supply Chain for Nuclear Medicine Ladimer S. Nagurney  

E-Print Network (OSTI)

The 99 Mo Supply Chain for Nuclear Medicine Ladimer S. Nagurney Department of Electrical November 13, 2012 #12;Nuclear Medicine: Meeting Patient Needs with 99 Mo Ladimer S. Nagurney The 99 Mo Supply Chain #12;Background and Motivation Study of Nuclear Medicine Supply Chains is a combination

Nagurney, Anna

37

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

DOE Patents (OSTI)

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.

Norman, Eric B. (Oakland, CA); Prussin, Stanley G. (Kensington, CA)

2007-10-02T23:59:59.000Z

38

Nuclear temperature effects in the scission-point model of nuclear fission  

Science Journals Connector (OSTI)

According to the scission-point model, the probability for a particular fission event can be expressed in terms of the collective potential and the collective kinetic energy at the scission point. Two additional assumptions make the scission-point model an easily calculable model: the assumption of equal collective kinetic energies for constant distances d between the tips of the fragments, and the assumption that one is able to characterize the excitation energy of the fragments with a nuclear temperature T, independent of both the mass ratio and the charge ratio, and of the deformations of the fragments. It is pointed out that the latter assumption violates energy conservation. A modified, recursive procedure is proposed, resulting in an "energy conservation consistent" scission-point method. Mass and charge distributions for the fission of U235 and Cf252 compound systems have been calculated and compared with distributions following the "standard" scission-point method of Wilkins, Steinberg, and Chasman.NUCLEAR REACTIONS Scission-point model. Collective potential and intrinsic excitation energy. Nuclear temperature T. Mass and charge distributions. Fission of U235 and C252.

J. Moreau; K. Heyde; M. Waroquier

1983-10-01T23:59:59.000Z

39

Molten salt considerations for accelerator-driven subcritical fission to close the nuclear fuel cycle  

SciTech Connect

The host salt selection, molecular modeling, physical chemistry, and processing chemistry are presented here for an accelerator-driven subcritical fission in a molten salt core (ADSMS). The core is fueled solely with the transuranics (TRU) and long-lived fission products (LFP) from used nuclear fuel. The neutronics and salt composition are optimized to destroy the transuranics by fission and the long-lived fission products by transmutation. The cores are driven by proton beams from a strong-focusing cyclotron stack. One such ADSMS system can destroy the transuranics in the used nuclear fuel produced by a 1GWe conventional reactor. It uniquely provides a method to close the nuclear fuel cycle for green nuclear energy.

Sooby, Elizabeth; Baty, Austin; Gerity, James; McIntyre, Peter; Melconian, Karie; Pogue, Nathaniel; Sattarov, Akhdiyor [Department of Physics and Astronomy, Texas A and M University, 4242 TAMU, College Station TX 77843 (United States); Adams, Marvin; Tsevkov, Pavel [Nuclear Engineering, Texas A and M University, Spence St., College Station TX 77843 (United States); Phongikaroon, Supathorn [Center for Advanced Energy Studies, University of Idaho, 995 University Blvd, Idaho Falls, ID 83401 (United States); Simpson, Michael; Tripathy, Prabhat [Materials Fuels Complex, Idaho National Laboratory, Idaho Falls, ID 83415 (United States)

2013-04-19T23:59:59.000Z

40

New developments in direct nuclear fission energy conversion devices  

SciTech Connect

Some experimental and theoretical results obtained in the investigations undertaken at the Central Institute of Physics (CIP) in Bucharest-Romania concerning the direct nuclear energy conversion into electrical energy are presented. Open-circuit voltages (U /SUB oc/ ) of tens of kV and short-circuit currents (J /SUB sc/ ) of several ..mu..A were obtained in experiments with vacuum fission-electric cells (FEC) developed in the CIP and irradiated in the VVR-S reactor at a 10/sup 9/ neutrons/cm/sup 2/s thermal neutron flux. A gas filled FEC (GAFFC) has been devised and tested in the reactor at the same neutron flux. With this GAFEC U /SUB oc/ of hundreds of kV, J /SUB sc/ of hundreds of ..mu..A and powers of hundreds of mW have been obtained. Our researches pointed out the essential part played by the electrons in the charge transport dynamics occuring in the FEC and the influence of the secondary emission on the FEC operation.

Ursu, I.; Badescu-Singureann, A.I.; Schachter, L.

1983-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "nuclear fission chain" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Spontaneous Fission Modes and Lifetimes of Superheavy Elements in the Nuclear Density Functional Theory  

SciTech Connect

Background: The reactions with the neutron-rich 48Ca beam and actinide targets resulted in the detection of new superheavy (SH) nuclides with Z=104 118. The unambiguous identification of the new isotopes, however, still poses a problem because their -decay chains terminate by spontaneous fission (SF) before reaching the known region of the nuclear chart. The understanding of the competition between -decay and SF channels in SH nuclei is, therefore, of crucial importance for our ability to map the SH region and to assess its extent.

Purpose: We perform self-consistent calculations of the competing decay modes of even-even SH isotopes with 108 Z 126 and 148 N 188.

Methods: We use the state-of-the-art computational framework based on self-consistent symmetry-unrestricted nuclear density functional theory capable of describing the competition between nuclear attraction and electrostatic repulsion. We apply the SkM* Skyrme energy density functional. The collective mass tensor of the fissioning superfluid nucleus is computed by means of the cranking approximation to the adiabatic time-dependent Hartree-Fock-Bogoliubov (HFB) approach. This paper constitutes a systematic self-consistent study of spontaneous fission in the SH region, carried out at a full HFB level, that simultaneously takes into account both triaxiality and reflection asymmetry.

Results: Breaking axial symmetry and parity turns out to be crucial for a realistic estimate of collective action; it results in lowering SF lifetimes by more than 7 orders of magnitude in some cases. We predict two competing SF modes: reflection symmetric modes and reflection asymmetric modes.

Conclusions: The shortest-lived SH isotopes decay by SF; they are expected to lie in a narrow corridor formed by 280Hs, 284Fl, and 118284Uuo that separates the regions of SH nuclei synthesized in cold-fusion and hot-fusion reactions. The region of long-lived SH nuclei is expected to be centered on 294Ds with a total half-life of 1.5 days. Our survey provides a solid benchmark for the future improvements of self-consistent SF calculations in the region of SH nuclei.

Staszczak, A, [UTK/ORNL/Inst. Physics, Maria Curie-Sklodowska University, Poland; Baran, A. [UTK/ORNL/Inst. Physics, Maria Curie-Sklodowska University, Poland; Nazarewicz, Witold [UTK/ORNL/University of Warsaw

2013-01-01T23:59:59.000Z

42

Discovery of a new mode of nuclear fission  

SciTech Connect

We measured the mass and kinetic-energy partitioning in the spontaneous fission of /sup 258/Fm, /sup 259/Md, /sup 260/Md, /sup 258/No, and /sup 260/(104). Surprisingly, these energy distributions were skewed upward or downward from the peak in each case, except for /sup 260/(104), indicating a composite of two energy distributions. We interpret this as a new mode of fission in which there is mixture of liquid-drop-like and fragment-shell-directed symmetric fission.

Hulet, E.K.; Wild, J.F.; Dougan, R.J.; Lougheed, R.W.; Landrum, J.H.; Dougan, A.D.; Schaedel, M.; Hahn, R.L.; Baisden, P.A.; Henderson, C.M.

1986-01-01T23:59:59.000Z

43

Medical Nuclear Supply Chain Design: A Tractable Network Model and Computational  

E-Print Network (OSTI)

Medical Nuclear Supply Chain Design: A Tractable Network Model and Computational Approach Anna Medical Nuclear Supply Chain Design #12;Outline Background and Motivation Supply Chain Challenges The Medical Nuclear Supply Chain Network Design Model The Computational Approach Summary and Suggestions

Nagurney, Anna

44

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

E-Print Network (OSTI)

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 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 239 Pu(n,f) reaction. 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 a function of the excitation energy of the compound nucleus. We show that the coupling to the continuum induced by the finite temperature is negligible in the range of neutron energies relevant for many applications of neutron-induced fission. We prove that the concept of quantum localization introduced recently can be extended to T > 0, and we apply the method to study the interaction energy and total kinetic energy of fission fragments as a function of the temperature for the most probable fission. While large uncertainties in theoretical modeling remain, we conclude that finite-temperature nuclear density functional may provide a useful framework to obtain accurate predictions of fission fragment properties.

N. Schunck; D. Duke; H. Carr

2015-01-23T23:59:59.000Z

45

Non-equilibrium fission processes in intermediate energy nuclear collisions  

SciTech Connect

We have measured the target fragment yields, angular and energy distributions for the interaction of 12-16 MeV/A/sup 32/S with /sup 165/Ho and /sup 197/Au and for the interaction of 32 and 44 MeV/A /sup 40/Ar with /sup 197/Au. The Au fission fragments associated with the peripheral collision peak in the folding angle distribution originate in a normal, ''slow'' fission process in which statistical equilibrium has been established. At the two lowest projectile energies, the Au fission fragments associated with the central collision peak in the folding angle distribution originate in part from ''fast'' (/tau//approximately//sup /minus/23/s), non-equilibrium processes. Most of the Ho fission fragments originate in non- equilibrium processes. The fast, non-equilibrium process giving rise to these fragments has many of the characteristics of ''fast fission'', but the cross sections associated with these fragments are larger than one would expect from current theories of ''fast fission. '' 14 refs., 8 figs.

Loveland, W.; Casey, C.; Xu, Z.; Seaborg, G.T.; Aleklett, K.; Sihver, L.

1989-04-01T23:59:59.000Z

46

Fusion–fission hybrids for nuclear waste transmutation: A synergistic step between Gen-IV fission and fusion reactors  

Science Journals Connector (OSTI)

Energy demand and GDP per capita are strongly correlated, while public concern over the role of energy in climate change is growing. Nuclear power plants produce 16% of world electricity demands without greenhouse gases. Generation-IV advanced nuclear energy systems are being designed to be safe and economical. Minimizing the handling and storage of nuclear waste is important. NIF and ITER are bringing sustainable fusion energy closer, but a significant gap in fusion technology development remains. Fusion–fission hybrids could be a synergistic step to a pure fusion economy and act as a technology bridge. We discuss how a pulsed power-driven Z-pinch hybrid system producing only 20 MW of fusion yield can drive a sub-critical transuranic blanket that transmutes 1280 kg of actinide wastes per year and produces 3000 MW. These results are applicable to other inertial and magnetic fusion energy systems. A hybrid system could be introduced somewhat sooner because of the modest fusion yield requirements and can provide both a safe alternative to fast reactors for nuclear waste transmutation and a maturation path for fusion technology. The development and demonstration of advanced materials that withstand high-temperature, high-irradiation environments is a fundamental technology issue that is common to both fusion–fission hybrids and Generation-IV reactors.

T.A. Mehlhorn; B.B. Cipiti; C.L. Olson; G.E. Rochau

2008-01-01T23:59:59.000Z

47

Fusion-fission hybrids for nuclear waste transmutation : a synergistic step between Gen-IV fission and fusion reactors.  

SciTech Connect

Energy demand and GDP per capita are strongly correlated, while public concern over the role of energy in climate change is growing. Nuclear power plants produce 16% of world electricity demands without greenhouse gases. Generation-IV advanced nuclear energy systems are being designed to be safe and economical. Minimizing the handling and storage of nuclear waste is important. NIF and ITER are bringing sustainable fusion energy closer, but a significant gap in fusion technology development remains. Fusion-fission hybrids could be a synergistic step to a pure fusion economy and act as a technology bridge. We discuss how a pulsed power-driven Z-pinch hybrid system producing only 20 MW of fusion yield can drive a sub-critical transuranic blanket that transmutes 1280 kg of actinide wastes per year and produces 3000 MW. These results are applicable to other inertial and magnetic fusion energy systems. A hybrid system could be introduced somewhat sooner because of the modest fusion yield requirements and can provide both a safe alternative to fast reactors for nuclear waste transmutation and a maturation path for fusion technology. The development and demonstration of advanced materials that withstand high-temperature, high-irradiation environments is a fundamental technology issue that is common to both fusion-fission hybrids and Generation-IV reactors.

Olson, Craig Lee; Mehlhorn, Thomas Alan; Cipiti, Benjamin B.; Rochau, Gary Eugene

2007-09-01T23:59:59.000Z

48

Prompt muon-induced fission: a probe for nuclear energy dissipation  

E-Print Network (OSTI)

We solve the time-dependent Dirac equation for a muon which is initially bound to a fissioning actinide nucleus. The computations are carried out on a 3-D cartesian lattice utilizing the Basis-Spline collocation method. The muon dynamics is sensitive to the nuclear energy dissipation between the outer fission barrier and the scission point. From a comparison with experimental data we find a dissipated energy of about 10 MeV and a fission time delay due to friction of order $2 \\times 10^{-21}$ s.

Volker E. Oberacker

1999-05-04T23:59:59.000Z

49

Fission fizzles: Estimating the yield of a predetonated nuclear weapon  

Science Journals Connector (OSTI)

An undergraduate-level model is developed for estimating the fraction of the design yield that can be realized if a uranium or a plutonium fission bomb suffers an uncontrolled predetonation due to a spontaneous fission of the fissile material. The model is based on the combination of one published earlier for the predetonation probability and a yield model developed by Mark et al. [“Explosive properties of reactor-grade plutonium ” Sci. Global Secur.17 (2) 170–185 (2009); a reprint of the same paper published in Sci. Global Secur.4 (1) 111–128 (1993)].

B. Cameron Reed

2011-01-01T23:59:59.000Z

50

Enrico Fermi Achieves First Self Sustain Nuclear Chain Reaction | National  

National Nuclear Security Administration (NNSA)

Enrico Fermi Achieves First Self Sustain Nuclear Chain Reaction | National Enrico Fermi Achieves First Self Sustain Nuclear Chain Reaction | National Nuclear Security Administration Our Mission Managing the Stockpile Preventing Proliferation Powering the Nuclear Navy Emergency Response Recapitalizing Our Infrastructure Continuing Management Reform Countering Nuclear Terrorism About Us Our Programs Our History Who We Are Our Leadership Our Locations Budget Our Operations Media Room Congressional Testimony Fact Sheets Newsletters Press Releases Speeches Events Social Media Video Gallery Photo Gallery NNSA Archive Federal Employment Apply for Our Jobs Our Jobs Working at NNSA Blog Home > About Us > Our History > NNSA Timeline > Enrico Fermi Achieves First Self Sustain Nuclear ... Enrico Fermi Achieves First Self Sustain Nuclear Chain Reaction

51

Interplay between compound and fragments aspects of nuclear fission and heavy-ion reaction  

SciTech Connect

The scission point in nuclear fission plays a special role where one-body system changes to two-body system. Inverse of this situation is realized in heavy-ion fusion reaction where two-body system changes to one body system. Among several peculiar phenomena expected to occur during this change, we focus our attention to the behavior of compound and fragments shell effects. Some aspects of the interplay between compound and fragments shell effect are discussed related to the topics of the fission valleys in the potential energy surface of actinide nuclei and the fusion-like trajectory found in the cold fusion reaction leading to superheavy nuclei.

Moller, Peter [Los Alamos National Laboratory; Iwamoto, A [JAPAN; Ichikawa, I [JAPAN

2010-09-10T23:59:59.000Z

52

Most Viewed Documents for Fission and Nuclear Technologies: December...  

Office of Scientific and Technical Information (OSTI)

Nicolas; Pruess, Karsten (2004) 21 Levelized Costs for Nuclear, Gas and Coal for Electricity, under the Mexican Scenario Palacios, J.C.; Alonso, G.; Ramirez, R.; Gomez, A.;...

53

March 2014 Most Viewed Documents for Fission And Nuclear Technologies...  

Office of Scientific and Technical Information (OSTI)

J. (1978) 30 > Reactor safety study. An assessment of accident risks in U. S. commercial nuclear power plants. Executive summary: main report. PWR and BWR Not Available (1975)...

54

Accelerator-driven subcritical fission in molten salt core: Closing the nuclear fuel cycle for green nuclear energy  

SciTech Connect

A technology for accelerator-driven subcritical fission in a molten salt core (ADSMS) is being developed as a basis for the destruction of the transuranics in used nuclear fuel. The molten salt fuel is a eutectic mixture of NaCl and the chlorides of the transuranics and fission products. The core is driven by proton beams from a strong-focusing cyclotron stack. This approach uniquely provides an intrinsically safe means to drive a core fueled only with transuranics, thereby eliminating competing breeding terms.

McIntyre, Peter; Assadi, Saeed; Badgley, Karie; Baker, William; Comeaux, Justin; Gerity, James; Kellams, Joshua; McInturff, Al; Pogue, Nathaniel; Sattarov, Akhdiyor; Sooby, Elizabeth; Tsvetkov, Pavel [Dept. of Physics, Texas A and M University, College Station, TX 77843 and Dept. of Nuclear Engineering, Texas A and M University, College Station, TX 77843 (United States); Phongikaroon, Supathorn; Simpson, Michael [Dept. of Chemical Engineering, University of Idaho, Idaho Falls ID 83402 (United States)

2013-04-19T23:59:59.000Z

55

Nuclear Fission Reactor Safety Research in FP7 and future perspectives  

E-Print Network (OSTI)

The European Union (?U) has defined in the Europe 2020 strategy and 2050 Energy Roadmap its long-term vision for establishing a secure, sustainable and competitive energy system and setting up legally binding targets by 2020 for reducing greenhouse emissions, by increasing energy efficiency and the share of renewable energy sources while including a significant share from nuclear fission. Nuclear energy can enable the further reduction in harmful emissions and can contribute to the EU’s competitive energy system, security of supply and independence from fossil fuels. Nuclear fission is a valuable option for those 14 EU countries that promote its use as part of their national energy mix. The European Group on Ethics in Science and New Technologies (EGE) adopted its Opinion No.27 ‘An ethical framework for assessing research, production and use of energy’ and proposed an integrated ethics approach for the research, production and use of energy in the EU, seeking equilibrium among four criteria – access ...

Garbil, Roger

2014-01-01T23:59:59.000Z

56

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

SciTech Connect

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

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

1999-02-17T23:59:59.000Z

57

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

DOE Patents (OSTI)

A method and a system for detecting the presence of special nuclear materials in a suspect container. The system and its method include irradiating the suspect container with a beam of neutrons, so as to induce a thermal fission in a portion of the special nuclear materials, detecting the gamma rays that are emitted from the fission products formed by the thermal 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.

Norman, Eric B. (Oakland, CA); Prussin, Stanley G. (Kensington, CA)

2009-01-27T23:59:59.000Z

58

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

DOE Patents (OSTI)

A method and a system for detecting the presence of special nuclear materials in a suspect container. The system and its method include irradiating the suspect container with a beam of neutrons, so as to induce a thermal fission in a portion of the special nuclear materials, detecting the gamma rays that are emitted from the fission products formed by the thermal 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.

Norman, Eric B. (Oakland, CA); Prussin, Stanley G. (Kensington, CA)

2009-01-06T23:59:59.000Z

59

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

DOE Patents (OSTI)

A method and a system for detecting the presence of special nuclear materials in a suspect container. The system and its method include irradiating the suspect container with a beam of neutrons, so as to induce a thermal fission in a portion of the special nuclear materials, detecting the gamma rays that are emitted from the fission products formed by the thermal 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.

Norman, Eric B [Oakland, CA; Prussin, Stanley G [Kensington, CA

2009-05-05T23:59:59.000Z

60

Disposition of plutonium from dismantled nuclear weapons: Fission options and comparisons  

SciTech Connect

Over the next decade, the United States expects to recover about 50 Mg of excess weapon plutonium and the Republic of Russia expects to recover a similar amount. Ensuring that these large quantities of high-grade material are not reused in nuclear weapons has drawn considerable attention. In response to this problem, the US Department of Energy (DOE) chartered the Plutonium Disposition Task Force (PDTF), in the summer of 1992, to assess a range of practical means for disposition of excess US plutonium. This report summarizes and compares the Fission Options'' provided to the Fission Working Group Review Committee (the committee) of the PDTF. The review by the committee was based on preliminary information received as of December 4, 1992, and as such the results summarized in this report should also be considered preliminary. The committee concluded that irradiation of excess weapon plutonium in fission reactors in conjunction with the generation of electricity and storing the spent fuel is a fast, cost-effective, and environmentally acceptable method of addressing the safeguards (diversion) issue. When applied appropriately, this method is consistent with current nonproliferation policy. The principal effect of implementing the fission options is at most a moderate addition of plutonium to that existing in commercial spent fuel. The amount of plutonium in commercial spent fuel by the year 2000 is estimated to be 300 Mg. The addition of 50 Mg of excess weapon plutonium, in this context, is not a determining factor, moreover, several of the fission options achieve substantial annihilation of plutonium.

Omberg, R.P. (Westinghouse Hanford Co., Richland, WA (United States)); Walter, C.E. (Lawrence Livermore National Lab., CA (United States))

1993-02-05T23:59:59.000Z

Note: This page contains sample records for the topic "nuclear fission chain" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Disposition of plutonium from dismantled nuclear weapons: Fission options and comparisons  

SciTech Connect

Over the next decade, the United States expects to recover about 50 Mg of excess weapon plutonium and the Republic of Russia expects to recover a similar amount. Ensuring that these large quantities of high-grade material are not reused in nuclear weapons has drawn considerable attention. In response to this problem, the US Department of Energy (DOE) chartered the Plutonium Disposition Task Force (PDTF), in the summer of 1992, to assess a range of practical means for disposition of excess US plutonium. This report summarizes and compares the ``Fission Options`` provided to the Fission Working Group Review Committee (the committee) of the PDTF. The review by the committee was based on preliminary information received as of December 4, 1992, and as such the results summarized in this report should also be considered preliminary. The committee concluded that irradiation of excess weapon plutonium in fission reactors in conjunction with the generation of electricity and storing the spent fuel is a fast, cost-effective, and environmentally acceptable method of addressing the safeguards (diversion) issue. When applied appropriately, this method is consistent with current nonproliferation policy. The principal effect of implementing the fission options is at most a moderate addition of plutonium to that existing in commercial spent fuel. The amount of plutonium in commercial spent fuel by the year 2000 is estimated to be 300 Mg. The addition of 50 Mg of excess weapon plutonium, in this context, is not a determining factor, moreover, several of the fission options achieve substantial annihilation of plutonium.

Omberg, R.P. [Westinghouse Hanford Co., Richland, WA (United States); Walter, C.E. [Lawrence Livermore National Lab., CA (United States)

1993-02-05T23:59:59.000Z

62

Neutronics of accelerator-driven subcritical fission for burning transuranics in used nuclear fuel  

SciTech Connect

We report the development of a conceptual design for accelerator-driven subcritical fission in a molten salt core (ADSMS). ADSMS is capable of destroying all of the transuranics at the same rate and proportion as they are produced in a conventional nuclear power plant. The ADSMS core is fueled solely by transuranics extracted from used nuclear fuel and reduces its radiotoxicity by a factor 10,000. ADSMS offers a way to close the nuclear fuel cycle so that the full energy potential in the fertile fuels uranium and thorium can be recovered.

Sattarov, A.; Assadi, S.; Badgley, K.; Baty, A.; Comeaux, J.; Gerity, J.; Kellams, J.; Mcintyre, P.; Pogue, N.; Sooby, E.; Tsvetkov, P.; Rosaire, G. [Texas A and M University, College Station, TX 77845 (United States); Mann, T. [Argone National Laboratory, Argone, IL (United States)

2013-04-19T23:59:59.000Z

63

Medical Nuclear Supply Chain Design: A Tractable Network Model and Computational  

E-Print Network (OSTI)

Medical Nuclear Supply Chain Design: A Tractable Network Model and Computational Approach Anna Chain Challenges The Medical Nuclear Supply Chain Network Design Model The Computational Approach Medical Nuclear Supply Chain Design #12;This presentation is based on the paper, "Medical Nuclear Supply

Nagurney, Anna

64

Most Viewed Documents - Fission and Nuclear Technologies | OSTI, US Dept of  

Office of Scientific and Technical Information (OSTI)

Most Viewed Documents - Fission and Nuclear Technologies Most Viewed Documents - Fission and Nuclear Technologies Metals design handbook Betts, W.S. (1988) Estimation of gas leak rates through very small orifices and channels. [From sealed PuO/sub 2/ containers under accident conditions] Bomelburg, H.J. () Graphite design handbook Ho, F.H. (1988) Motor-operated valve (MOV) actuator motor and gearbox testing DeWall, K.; Watkins, J.C.; Bramwell, D. [Lockheed Idaho Technologies Co., Idaho Falls, ID (United States)] (1997) Environmental Aspects, Objectives and Targets Identification Process R. Green (2002) Flow-induced vibration of circular cylindrical structures Chen, S.S. (1985) System Definition and Analysis: Power Plant Design and Layout NONE (1996) Materials and design bases issues in ASME Code Case N-47 Huddleston, R.L.; Swindeman, R.W. (Oak Ridge National Lab., TN (United

65

Nuclear fission: the interplay of science and technology  

Science Journals Connector (OSTI)

...the present radioactive waste () came from early weapons...nuclear energy from such waste, and there are schemes...involve a decision between long-term storage (i.e. with access...medium-level and high-level wastes. How a particular radioactive...

2010-01-01T23:59:59.000Z

66

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

E-Print Network (OSTI)

testing of the ENDF/B-VII.1 library is provided for a variety of quantities: For nuclear criticalityENDF/B-VII.1 Nuclear Data for Science and Technology: Cross Sections, Covariances, Fission Product Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia 11 Nuclear Research and Consultancy Group, P

Danon, Yaron

67

Deployment of a three-dimensional array of micro-pocket fission detector triads (MPFD[superscript]3) for real-time, in-core neutron flux measurements in the Kansas State University TRIGA Mark-II Nuclear Reactor.  

E-Print Network (OSTI)

??A Micro-Pocket Fission Detector (MPFD) is a miniaturized type of fission chamber developed for use inside a nuclear reactor. Their unique design allows them to… (more)

Ohmes, Martin Francis

2012-01-01T23:59:59.000Z

68

Low-Energy Fusion-Fission Dynamics of Heavy Nuclear Systems  

SciTech Connect

A new approach is proposed for a unified description of strongly coupled deep-inelastic (DI) scattering, fusion, fission, and quasi-fission (QF) processes of heavy ion collisions. A unified driving-potential and a unified set of dynamic Langevin-type equations of motion are used in this approach. This makes it possible to perform a full (continuous) time analysis of the evolution of heavy nuclear systems, starting from the approaching stage, moving up to the formation of the compound nucleus or emerging into two final fragments. The calculated mass, charge, energy and angular distributions of the reaction products agree well with the corresponding experimental data for heavy and superheavy nuclear systems. Collisions of very heavy nuclei (such as 238U+248Cm) are investigated as an alternative way for production of superheavy elements. Large charge and mass transfer was found in these reactions due to the inverse (anti-symmetrizing) quasi-fission process leading to formation of surviving superheavy long-lived neutron-rich nuclei.

Zagrebaev, Valery [Flerov Laboratory of Nuclear Reaction, JINR, Dubna, 141980, Moscow region (Russian Federation); Greiner, Walter [Frankfurt Institute for Advanced Studies, J.W. Goethe-Universitaet, Frankfurt (Germany)

2006-08-14T23:59:59.000Z

69

Absolute nuclear material assay  

DOE Patents (OSTI)

A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

Prasad, Manoj K. (Pleasanton, CA); Snyderman, Neal J. (Berkeley, CA); Rowland, Mark S. (Alamo, CA)

2012-05-15T23:59:59.000Z

70

NUCLEAR SCIENCE AND ENGINEERING: 124, 482-491 (1996) Fission Cross-Section Measurements of the Odd-Odd  

E-Print Network (OSTI)

NUCLEAR SCIENCE AND ENGINEERING: 124, 482-491 (1996) Fission Cross-Section Measurements of the Odd-Odd Isotopes 232Pa, 238Np, and 236Np Y. Danon* Rensselaer Polytechnic Institute, Department of Nuclear Engineering and Engineering Physics Troy, New York 12180 M. S. Moore, P. E. Koehler,t P. E. Littleton, G. G

Danon, Yaron

71

Spontaneous fission modes and lifetimes of super-heavy elements in the nuclear density functional theory  

E-Print Network (OSTI)

Lifetimes of super-heavy (SH) nuclei are primarily governed by alpha decay and spontaneous fission (SF). Here we study the competing decay modes of even-even SH isotopes with 108 density functional theory framework capable of describing the competition between nuclear attraction and electrostatic repulsion. The collective mass tensor of the fissioning superfluid nucleus is computed by means of the cranking approximation to the adiabatic time-dependent Hartree-Fock-Bogoliubov approach. Along the path to fission, our calculations allow for the simultaneous breaking of axial and space inversion symmetries; this may result in lowering SF lifetimes by more than seven orders of magnitude in some cases. We predict two competing SF modes: reflection-symmetric and reflection-asymmetric.The shortest-lived SH isotopes decay by SF; they are expected to lie in a narrow corridor formed by $^{280}$Hs, $^{284}$Fl, and $^{284}_{118}$Uuo that separates the regions of SH nuclei synthesized in "cold fusion" and "hot fusion" reactions. The region of long-lived SH nuclei is expected to be centered on $^{294}$Ds with a total half-life of ?1.5 days.

A. Staszczak; A. Baran; W. Nazarewicz

2012-08-06T23:59:59.000Z

72

Medical Nuclear Supply Chain Design: A Tractable Network Model and Computational Approach  

E-Print Network (OSTI)

Medical Nuclear Supply Chain Design: A Tractable Network Model and Computational Approach Anna of medical nuclear supply chains. Our focus is on the molybdenum supply chain, which is the most commonly is of special relevance to healthcare given the medical nuclear product's widespread use as well as the aging

Nagurney, Anna

73

India's Nuclear Energy Program : prospects The talk will begin with a brief introduction to nuclear fission  

E-Print Network (OSTI)

India's Nuclear Energy Program : prospects The talk will begin with a brief introduction to nuclear posed by reactors, the accident liability laws and regulatory structure governing nuclear energy, Wednesday, Oct 29th 4:00 PM (Tea/Coffee at Seminar Hall, TCIS Colloquium India's Nuclear Energy Program

Shyamasundar, R.K.

74

Reconversion of nuclear weapons  

E-Print Network (OSTI)

The nuclear predicament or nuclear option. Synopsis of three lectures : 1- The physical basis of nuclear technology. Physics of fission. Chain reaction in reactors and weapons. Fission fragments. Separration of isotopes. Radiochemistry.2- Nuclear reactors with slow and fast neutrons. Power, size, fuel and waste. Plutonium production. Dose rate, shielding and health hazard. The lessons of Chernobyl3- Nuclear weapons. Types, energy, blast and fallout. Fusion and hydrogen bombs. What to do with nuclear weapons when you cannot use them? Testing. Nonmilittary use. Can we get rid of the nuclear weapon? Nuclear proliferation. Is there a nuclear future?

Kapitza, Sergei P

1993-01-01T23:59:59.000Z

75

X-ray imaging, spacecraft nuclear fission and cosmic ray contraband  

NLE Websites -- All DOE Office Websites (Extended Search)

R&D 100 Awards winners R&D 100 Awards winners X-ray imaging, spacecraft nuclear fission and cosmic ray contraband detection score R&D 100 awards R&D Magazine announced the winners and three technologies from Los Alamos National Laboratory and its partners are among the honorees. July 8, 2013 MiniMAX is a battery powered, digital x-ray imaging system that is completely self-contained, lightweight, compact and portable. MiniMAX is a battery powered, digital x-ray imaging system that is completely self-contained, lightweight, compact and portable. Contact Nancy Ambrosiano Communications Office (505) 667-0471 Email "The innovation and creativity shown in this year's awards is truly inspiring. It gives me great confidence in the Laboratory's intellectual vitality and ongoing role in national security science. Congratulations to

76

Detecting a Nuclear Fission Reactor at the Center of the Earth  

E-Print Network (OSTI)

A natural nuclear fission reactor with a power output of 3- 10 terawatt at the center of the earth has been proposed as the energy source of the earth's magnetic field. The proposal can be directly tested by a massive liquid scintillation detector that can detect the signature spectrum of antineutrinos from the geo-reactor as well as the direction of the antineutrino source. Such detectors are now in operation or under construction in Japan/Europe. However, the clarity of both types of measurements may be limited by background from antineutrinos from surface power reactors. Future U. S. detectors, relatively more remote from power reactors, may be more suitable for achieving unambiguous spectral and directional evidence for a 3TW geo-reactor.

R. S. Raghavan

2002-08-23T23:59:59.000Z

77

Fuel Performance Experiments and Modeling: Fission Gas Bubble Nucleation and Growth in Alloy Nuclear Fuels  

SciTech Connect

Advanced fast reactor systems being developed under the DOE's Advanced Fuel Cycle Initiative are designed to destroy TRU isotopes generated in existing and future nuclear energy systems. Over the past 40 years, multiple experiments and demonstrations have been completed using U-Zr, U-Pu-Zr, U-Mo and other metal alloys. As a result, multiple empirical and semi-empirical relationships have been established to develop empirical performance modeling codes. many mechamistic questions about fission as mobility, bubble coalescience, and gas release have been answered through industrial experience, reearch, and empirical understanding. The advent of modern computational materials science, however, opens new doors of development such that physics-based multi-scale models may be developed to enable a new generation of predictive fuel performance codes that are not limited by empiricism.

McDeavitt, Sean; Shao, Lin; Tsvetkov, Pavel; Wirth, Brian; Kennedy, Rory

2014-04-07T23:59:59.000Z

78

3He- and 4He-induced nuclear fission - a test of the transition state method  

E-Print Network (OSTI)

Fission in 3He and 4He induced reactions at excitation energies between the fission barrier and 140 MeV has been investigated. Twentythree fission excitation functions of various compound nuclei in different mass regions are shown to scale exactly according to the transition state prediction once the shell effects are accounted for. New precise measurements of excitation functions in a mass region where shell effects are very strong, allow one to test the predictions with an even higher accuracy. The fact that no deviations from the transition state method have been observed within the experimentally investigated excitation energy regime allows one to assign limits for the fission transient time. The precise measurement of fission excitation functions of neighboring isotopes enables us to experimentally estimate the first chance fission probability. Even if only first chance fission is investigated, no evidence for fission transient times larger than 30 zs can be found.

Th. Rubehn; K. X. Jing; L. G. Moretto; L. Phair; K. Tso; G. J. Wozniak

1997-04-18T23:59:59.000Z

79

Glossary of Nuclear Waste Terms  

NLE Websites -- All DOE Office Websites (Extended Search)

measures 12 feet in diameter by 22 feet long and weighs 200 tons. Chain Reaction A self-sustaining series of nuclear fissions taking place in a reactor core. Neutrons produced in...

80

Enrico Fermi and the First Self-Sustaining Nuclear Chain Reaction  

Office of Scientific and Technical Information (OSTI)

the first self-sustaining chain reaction and thereby initiated the controlled release of nuclear energy." Fermi's momentous accomplishments caused him to be recognized as one of...

Note: This page contains sample records for the topic "nuclear fission chain" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Mass and nuclear charge yields for 237Np(2nth,f) at different fission fragment kinetic energies  

Science Journals Connector (OSTI)

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: 23993Np; this odd-Z nucleus is formed after double thermal neutron capture in a 23993Np 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 24094Pu. At high kinetic energy, the mass distribution shows a prominent peak around mass number AL = 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 ± 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.

G. Martinez; G. Barreau; A. Sicre; T.P. Doan; P. Audouard; B. Leroux; W. Arafa; R. Brissot; J.P. Bocquet; H. Faust; P. Koczon; M. Mutterer; F. Gönnenwein; M. Asghar; U. Quade; K. Rudolph; D. Engelhardt; E. Piasecki

1990-01-01T23:59:59.000Z

82

Absolute nuclear material assay using count distribution (LAMBDA) space  

DOE Patents (OSTI)

A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

Prasad, Manoj K. (Pleasanton, CA); Snyderman, Neal J. (Berkeley, CA); Rowland, Mark S. (Alamo, CA)

2012-06-05T23:59:59.000Z

83

Neutron Transport and Nuclear Burnup Analysis for the Laser Inertial Confinement Fusion-Fission Energy (LIFE) Engine  

SciTech Connect

Lawrence Livermore National Laboratory is currently developing a hybrid fusion-fission nuclear energy system, called LIFE, to generate power and burn nuclear waste. We utilize inertial confinement fusion to drive a subcritical fission blanket surrounding the fusion chamber. It is composed of TRISO-based fuel cooled by the molten salt flibe. Low-yield (37.5 MJ) targets and a repetition rate of 13.3 Hz produce a 500 MW fusion source that is coupled to the subcritical blanket, which provides an additional gain of 4-8, depending on the fuel. In the present work, we describe the neutron transport and nuclear burnup analysis. We utilize standard analysis tools including, the Monte Carlo N-Particle (MCNP) transport code, ORIGEN2 and Monteburns to perform the nuclear design. These analyses focus primarily on a fuel composed of depleted uranium not requiring chemical reprocessing or enrichment. However, other fuels such as weapons grade plutonium and highly-enriched uranium are also under consideration. In addition, we have developed a methodology using {sup 6}Li as a burnable poison to replace the tritium burned in the fusion targets and to maintain constant power over the lifetime of the engine. The results from depleted uranium analyses suggest up to 99% burnup of actinides is attainable while maintaining full power at 2GW for more than five decades.

Kramer, K J; Latkowski, J F; Abbott, R P; Boyd, J K; Powers, J J; Seifried, J E

2008-10-24T23:59:59.000Z

84

Traces of fission products in southeast Spain after the Fukushima nuclear accident  

Science Journals Connector (OSTI)

Traces of 131I, 134Cs and 137Cs were measured after the Fukushima nuclear accident between 23 March and 13 April 2011 in southeast Spain. The movement of the radioactive cloud toward southeast Spain was reconstructed based on the backward and forward trajectory cluster analyses. Polar maritime air masses which had originated over North America transported the radioactive plume toward the southeast Spain. Aerosols, rainwater, vegetables and cheese were analyzed to determine the radioactive risk. The highest concentrations of 131I, 134Cs and 137Cs in air samples were 2.63 ± 0.12 mBq/m3; 0.10 ± 0.03 mBq/m3; 0.09 ± 0.02 mBq/m3, respectively. After precipitation on April 3rd, the maximum concentrations of 131I, 134Cs and 137Cs were detected in rainwater samples, 1.10 ± 0.16 mBq/L; 0.022 ± 0.003 mBq/L; 0.05 ± 0.03 mBq/L, respectively. As a consequence, 131I was transferred to the human food chain, and found in chard and goat cheese, 0.97 ± 0.20 Bq/kg and 0.52 ± 0.08 Bq/kg, respectively. The traces of 131I, 134Cs and 137Cs detected in the different samples were so low, that there is no impact on human health or the environment in Spain after the Fukushima nuclear accident.

F. Piñero García; M.A. Ferro García

2012-01-01T23:59:59.000Z

85

Record of Cycling Operation of the Natural Nuclear Reactor in the Oklo/Okelobondo Area in Gabon  

E-Print Network (OSTI)

of variability of the long-term fundamental physical constants [5,6] to storage of nuclear wastes in geological on how to retain nuclear wastes, including fission Xe and Kr, and prevent uncontrolled runaway chain

86

New Nuclear Reaction  

Science Journals Connector (OSTI)

Thermonuclear-like reaction points to possibilities for better kind of nuclear energy ... FISSION can make a chain reaction take place, as can fusion. ... To these two, scientists at University of California Radiation Laboratory have added a third: a "catalyzed nuclear reaction," a reaction that yields energy and is akin to fusion (thermonuclear) reactions. ...

1957-01-14T23:59:59.000Z

87

Inhibition of splicing and nuclear retention of pre-mRNA by spliceostatin A in fission yeast  

SciTech Connect

Nuclear retention of pre-mRNAs is tightly regulated by several security mechanisms that prevent pre-mRNA export into the cytoplasm. Recently, spliceostatin A, a methylated derivative of a potent antitumor microbial metabolite FR901464, was found to cause pre-mRNA accumulation and translation in mammalian cells. Here we report that spliceostatin A also inhibits splicing and nuclear retention of pre-mRNA in a fission yeast strain that lacks the multidrug resistance protein Pmd1. As observed in mammalian cells, spliceostatin A is bound to components of the SF3b complex in the spliceosome. Furthermore, overexpression of nup211, a homolog of Saccharomyces cerevisiae MLP1, suppresses translation of pre-mRNAs accumulated by spliceostatin A. These results suggest that the SF3b complex has a conserved role in pre-mRNA retention, which is independent of the Mlp1 function.

Lo, Chor-Wai [Chemical Genetics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Department of Biotechnology, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657 (Japan); Kaida, Daisuke; Nishimura, Shinichi; Matsuyama, Akihisa; Yashiroda, Yoko; Taoka, Hiroshi [Chemical Genetics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Ishigami, Ken; Watanabe, Hidenori [Department of Applied Biological Chemistry, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657 (Japan); Nakajima, Hidenori [Drug Discovery Research, Fermentation Research Laboratories, Astellas Pharma Inc., 5-2-3 Tokodai, Tsukuba, Ibaraki 300-2698 (Japan); Tani, Tokio [Department of Biological Sciences, Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Horinouchi, Sueharu [Department of Biotechnology, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657 (Japan); Yoshida, Minoru [Chemical Genetics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Japan Science and Technology Corporation (JST), CREST Research Project, Kawaguchi, Saitama 332-0012 (Japan)], E-mail: yoshidam@riken.jp

2007-12-21T23:59:59.000Z

88

High Temperature Materials for Nuclear Fast Fission and Fusion Reactors and Advanced Fossil Power Plants  

Science Journals Connector (OSTI)

Development of materials plays a crucial role in the economic feasibility of fast nuclear fission and fusion power plant. In order to meet this objective, one of the methods is to extend the fuel burnup and decreasing doubling time. The burnup is largely limited by the void swelling and creep resistances of the fuel cladding and wrapping materials. India's 500 \\{MWe\\} Prototype Fast Breeder Reactor (PFBR) is in advanced stage of construction. The major structural materials chosen for PFBR with MOX fuel are alloy D9 as fuel clad and wrapper material, 316LN austenitic stainless steel for reactor components and piping and modified 9Cr-1Mo steel for steam generator. In order to improve the burnup further, titanium, phosphorous and silicon contents in alloy D9 have been optimized for better swelling and creep resistances to develop modified version of alloy D9 as IFAC-1. Creep resistance of inherently void swelling resistance 9Cr-ferritic steel has been improved with the dispersion of nano-size yttria to develop oxide dispersion strengthened (ODS) steel clad tube with long- term creep strength, similar to D9, for increasing the fuel burnup. Development of modified 9Cr-1Mo steel clad tube and 9Cr-1Mo steel wrapper for future metallic fuel reactors being developed for reducing the doubling time are in progress. Extensive studies on resistance of this new generation core materials to void swelling are also under progress along with material development. Improved versions of 316LN stainless steel with nitrogen content of about 0.14 wt.% having higher creep strength to increase the life of fast reactor and modified 9Cr-1Mo steel with reduced nitrogen content and controlled addition of boron to improve type IV cracking resistance for steam generator are other developments. India's participation in ITER programme necessitates the development of India-specific RAFM steel for Test Blanket Module (TBM). A comprehensive research programme is being carried out to develop India-specific 9Cr-W-Ta RAFM steel with the optimization of tungsten and tantalum contents for better combination of strength and toughness. Based of the extensive mechanical tests including impact, tensile, creep and fatigue on four heats of RAFM steels having tungsten in the range 1 – 2 wt. % and tantalum in the range 0.06 -.014 wt., the RAFM steel having 1.4 wt. % tungsten with 0.06 wt. % tantalum is found to possess better combination of strength and toughness. This steel is considered as India-specific RAFM steel and TBM is being manufactured by this RAFM steel. To limit the emission of green house gases, a research and development programme has been initiated to develop advanced ultra super critical fossil fuel fired thermal power plants working at temperature of around 973 K and pressure of 300 bar. High temperature creep strength super 304H austenitic steel and Inconel 617 superalloy tubes are indigenously developed for this purpose.

T. Jayakumar; M.D. Mathew; K. Laha

2013-01-01T23:59:59.000Z

89

Scaling Laws and Transient Times in 3He Induced Nuclear Fission  

E-Print Network (OSTI)

Fission excitation functions of compound nuclei in a mass region where shell effects are expected to be very strong are shown to scale exactly according to the transition state prediction once these shell effects are accounted for. The fact that no deviations from the transition state method have been observed within the experimentally investigated excitation energy regime allows one to assign an upper limit for the transient time of 10 zs.

Th. Rubehn; K. X. Jing; L. G. Moretto; L. Phair; K. Tso; G. J. Wozniak

1996-07-09T23:59:59.000Z

90

A long term radiological risk model for plutonium-fueled and fission reactor space nuclear system  

SciTech Connect

This report describes the optimization of the RISK III mathematical model, which provides risk assessment for the use of a plutonium-fueled, fission reactor in space systems. The report discusses possible scenarios leading to radiation releases on the ground; distinctions are made for an intact reactor and a dispersed reactor. Also included are projected dose equivalents for various accident situations. 54 refs., 31 figs., 11 tabs. (TEM)

Bartram, B.W.; Dougherty, D.K.

1987-01-01T23:59:59.000Z

91

Geochemistry of organic-rich black shales overlying the natural nuclear fission reactors of Oklo, Republic of Gabon  

SciTech Connect

The organic-rich black shales of the Franceville Series` FB Formation overlying the uranium ores, and natural nuclear fission reactors of Oklo, Gabon, are not notably metalliferous. Chromium, gold, silver, and barium are slightly enriched in average Oklo black shale (AOK) relative to black shale standard SDO-1. Geochemical variations among the black shale samples of the sedimentary sequence include enrichment in potassium, barium, chromium, and silver in the four lowermost samples, the presence of a bleached zone depleted in organic carbon lowermost in the sequence, and elevated rare earth element (REE) content in samples closest to the Oklo reactor zones. Hydrothermal activity has influenced the geochemistry of the black shale but is evidently not linked to reactor-driven processes. Chondrite-normalized REE patterns of Oklo black shale samples show slight enrichment in light REE and slight depletion in heavy REE, especially in the sample closest to the reactor zone. However, comparison of REE content with various petrographic facies in and near the Oklo reactors shows no apparent enrichment in fission product (intermediate) REE. With few exceptions, reactor facies all contain more REE than AOK. The chondrite-normalized REE pattern of AOK resembles that of greywacke-shale turbidites of Archean greenstone belts. The paucity of uranium and manganese in AOK is a curious anomaly in an area of world class uranium and manganese deposits.

Mossman, D.J. [Mount Allison Univ., Sackville, New Brunswick (Canada). Dept. of Physics, Engineering and Geoscience; Gauthier-Lafaye, F. [Centre National de la Recherche Scientifique, Strasbourg (France). Centre de Geochimie de la Surface; Nagy, B.; Rigali, M.J. [Univ. of Arizona, Tucson, AZ (United States)

1998-07-01T23:59:59.000Z

92

Neutrinoless $??$ decay nuclear matrix elements in an isotopic chain  

E-Print Network (OSTI)

We analyze nuclear matrix elements (NME) of neutrinoless double beta decay calculated for the Cadmium isotopes. Energy density functional methods including beyond mean field effects such as symmetry restoration and shape mixing are used. Strong shell effects are found associated to the underlying nuclear structure of the initial and final nuclei. Furthermore, we show that NME for two-neutrino double beta decay evaluated in the closure approximation, $M^{2\

Tomás R. Rodríguez; Gabriel Martínez-Pinedo

2012-10-11T23:59:59.000Z

93

Scaling laws, transient times and shell effects in helium induced nuclear fission  

E-Print Network (OSTI)

Fission excitation functions of He-3 and He-4 induced compound nuclei are shown to scale exactly according to the Bohr-Wheeler transition state prediction once the shell effects are accounted for. The presented method furthermore allows one to model-independently extract values for the shell effects which are in good agreement to those obtained from liquid-drop model calculations. The fact that no deviations from the transition state method have been observed within the experimentally investigated excitation energy regime allows one to assign an upper limit for the transient time of 10 zs.

Th. Rubehn; K. X. Jing; L. G. Moretto; L. Phair; K. Tso; G. J. Wozniak

1996-07-22T23:59:59.000Z

94

Signatures of special nuclear material: High-energy gamma rays followi ng fission  

E-Print Network (OSTI)

of Special Nuclear Material: High-Energy ? Rays Followingmaterials tested showed much longer decay times. These two features – large numbers of high-energy

2003-01-01T23:59:59.000Z

95

Characterization of a Stochastic Procedure for the Generation and Transport of Fission Fragments within Nuclear Fuels  

E-Print Network (OSTI)

With the ever-increasing demands of the nuclear power community to extend fuel cycles and overall core-lifetimes in a safe and economic manner, it is becoming more necessary to extend the working knowledge of nuclear fuel performance. From...

Hackemack, Michael Wayne

2013-04-15T23:59:59.000Z

96

Use of curium spontaneous fission neutrons for safeguardability of remotely-handled nuclear facilities: Fuel fabrication in pyroprocessing  

Science Journals Connector (OSTI)

Abstract Advanced nuclear reactor systems (NESs) will utilize remotely-handled facilities in which batch-type processing will occur in hot cells. There are no current formalized criteria for International Atomic Energy Agency (IAEA) safeguards for these systems. This creates new challenges to develop methodologies for demonstrating the safeguardability of these facilities. A High Reliability Safeguards (HRS) approach therefore has been proposed to enhance intrinsic proliferation resistance by establishing an envelope of adaptable functional components as part of a facility design strategy. Additionally, system assessment can be modeled concurrently with safety and physical security by a risk-informed approach. The HRS approach is currently applied to a commercial pyroprocessing facility as an example system. A scoping study is presented as the first in a series of quantitative modeling efforts to extend the HRS approach. These efforts currently focus on investigating the magnitude of neutron fluxes due to spontaneous fission of curium for commercial batch sizes and held up materials for important processes in the system. Here, the fuel fabrication process is studied. The intent of these initial studies is to learn how the intrinsic properties of materials in the pyroprocessing system will affect facility design and safeguards. The model presented in this paper is intended to be adaptable to more practical and complex scenarios in order to evaluate the safeguardability of remotely-handled nuclear facilities.

R.A. Borrelli

2013-01-01T23:59:59.000Z

97

Nuclear Fission: For Safe, Globally Sustainable, Proliferation-Resistant, and Cost-Effective Energy  

Science Journals Connector (OSTI)

To varying degrees, under varying priorities, and depending strongly on country/region, the advancement of nuclear energy must deal with four cardinal issues: waste, proliferation, cost, and safety. While solutio...

R. A. Krakowski; L. Bennett; E. Bertel

1999-01-01T23:59:59.000Z

98

Role of organic matter in the Proterozoic Oklo natural fission reactors, Gabon, Africa  

SciTech Connect

Of the sixteen known Oklo and the Bangombe natural fission reactors (hydrothermally altered elastic sedimentary rocks that contain abundant uraninite and authigenic clay minerals), reactors 1 to 6 at Oklo contain only traces of organic matter, but the others are rich in organic substances. Reactors 7 to 9 are the subjects of this study. These organic-rich reactors may serve as time-tested analogues for anthropogenic nuclear-waste containment strategies. Organic matter helped to concentrate quantities of uranium sufficient to initiate the nuclear chain reactions. Liquid bitumen was generated from organic matter by hydrothermal reactions during nuclear criticality. The bitumen soon became a solid, consisting of polycyclic aromatic hydrocarbons and an intimate mixture of cryptocrystalline graphite, which enclosed and immobilized uraninite and the fission-generated isotopes entrapped in uraninite. This mechanism prevented major loss of uranium and fission products from the natural nuclear reactors for 1.2 b.y. 24 refs., 4 figs.

Nagy, B.; Rigali, M.J. [Univ. of Arizona, Tucson (United States)] [Univ. of Arizona, Tucson (United States); Gauthier-Lafaye, F. [Centre de Geochemie de la Surface, Strasbourg (France)] [Centre de Geochemie de la Surface, Strasbourg (France); Holliger, P. [Centre d`Etudes Nucleaires de Cadarache (France)] [Centre d`Etudes Nucleaires de Cadarache (France); Mossman, D.J. [Mount Allison Univ., Sackville, New Brunswick (Canada)] [Mount Allison Univ., Sackville, New Brunswick (Canada); Leventhal, J.S. [Geological Survey, Denver, CO (United States)] [Geological Survey, Denver, CO (United States)

1993-07-01T23:59:59.000Z

99

Laser Inertial Fusion-based Energy: Neutronic Design Aspects of a Hybrid Fusion-Fission Nuclear Energy System  

E-Print Network (OSTI)

DT Deuterium-Tritium DU Depleted Uranium FIMA Fission ofengine loaded with depleted uranium. In Proc. PHYSOR 2010,fuel layer comprised of depleted uranium contained in

Kramer, Kevin James

2010-01-01T23:59:59.000Z

100

A comparative analysis of accident risks in fossil, hydro, and nuclear energy chains  

SciTech Connect

This study presents a comparative assessment of severe accident risks in the energy sector, based on the historical experience of fossil (coal, oil, natural gas, and LPG (Liquefied Petroleum Gas)) and hydro chains contained in the comprehensive Energy-related Severe Accident Database (ENSAD), as well as Probabilistic Safety Assessment (PSA) for the nuclear chain. Full energy chains were considered because accidents can take place at every stage of the chain. Comparative analyses for the years 1969-2000 included a total of 1870 severe ({>=} 5 fatalities) accidents, amounting to 81,258 fatalities. Although 79.1% of all accidents and 88.9% of associated fatalities occurred in less developed, non-OECD countries, industrialized OECD countries dominated insured losses (78.0%), reflecting their substantially higher insurance density and stricter safety regulations. Aggregated indicators and frequency-consequence (F-N) curves showed that energy-related accident risks in non-OECD countries are distinctly higher than in OECD countries. Hydropower in non-OECD countries and upstream stages within fossil energy chains are most accident-prone. Expected fatality rates are lowest for Western hydropower and nuclear power plants; however, the maximum credible consequences can be very large. Total economic damages due to severe accidents are substantial, but small when compared with natural disasters. Similarly, external costs associated with severe accidents are generally much smaller than monetized damages caused by air pollution.

Burgherr, P.; Hirschberg, S. [Paul Scherrer Institute, Villigen (Switzerland)

2008-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "nuclear fission chain" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Mass-Yield Distribution of the Fission Products in Fallout from the 14 May 1965 Nuclear Explosion  

Science Journals Connector (OSTI)

...neutron-induced fission of uranium-235, except for the...strontium-90 were markedly depleted and the yields near the...IN FALLOUT PARTICLES, HEALTH PHYSICS 11 : 199 ( 1965...SPONTANEOUS FISSION OF URANIUM-238, JOURNAL OF INORGANIC...strontium-90 were markedly depleted and the yields near the...

M. N. Rao; Kazuko Yoshikawa; D. D. Sabu; R. Clark; P. K. Kuroda

1966-08-05T23:59:59.000Z

102

Monitoring system for a liquid-cooled nuclear fission reactor. [PWR  

DOE Patents (OSTI)

The invention provides improved means for detecting the water levels in various regions of a water-cooled nuclear power reactor, viz., in the downcomer, in the core, in the inlet and outlet plenums, at the head, and elsewhere; and also for detecting the density of the water in these regions. The invention utilizes a plurality of exterior gamma radiation detectors and a collimator technique operable to sense separate regions of the reactor vessel to give respectively, unique signals for these regions, whereby comparative analysis of these signals can be used to advise of the presence and density of cooling water in the vessel.

DeVolpi, A.

1984-07-20T23:59:59.000Z

103

STABILIZING GLASS BONDED WASTE FORMS CONTAINING FISSION PRODUCTS SEPARATED FROM SPENT NUCLEAR FUEL  

SciTech Connect

A model has been developed to represent the stresses developed when a molten, glass-bonded brittle cylinder (used to store nuclear material) is cooled from high temperature to working temperature. Large diameter solid cylinders are formed by heating glass or glass-bonded mixtures (mixed with nuclear waste) to high temperature (915°C). These cylinders must be cooled as the final step in preparing them for storage. Fast cooling time is desirable for production; however, if cooling is too fast, the cylinder can crack into many pieces. To demonstrate the capability of the model, cooling rate cracking data were obtained on small diameter (7.8 cm diameter) glass-only cylinders. The model and experimental data were combined to determine the critical cooling rate which separates the non-cracking stable glass region from the cracked, non-stable glass regime. Although the data have been obtained so far only on small glass-only cylinders, the data and model were used to extrapolate the critical-cooling rates for large diameter ceramic waste form (CWF) cylinders. The extrapolation estimates long term cooling requirements. While a 52-cm diameter cylinder (EBR-II-waste size) can be cooled to 100°C in 70 hours without cracking, a 181.5-cm diameter cylinder (LWR waste size) requires 35 days to cool to 100°C. These cooling times are long enough that verification of these estimates are required so additional experiments are planned on both glass only and CWF material.

Kenneth J. Bateman; Charles W. Solbrig

2008-07-01T23:59:59.000Z

104

Report to the DOE nuclear data committee. [EV RANGE 10-100; CROSS SECTIONS; PHOTONEUTRONS; NEUTRONS; GAMMA RADIATION; COUPLED CHANNEL THEORY; DIFFERENTIAL CROSS SECTIONS; MEV RANGE 01-10; ; CAPTURE; GAMMA SPECTRA; THERMAL NEUTRONS; COMPUTER CALCULATIONS; DECAY; FISSION PRODUCTS; FISSION YIELD; SHELL MODELS; NUCLEAR DATA COLLECTIONS  

SciTech Connect

Topics covered include: studies of (n, charged particle) reactions with 14 to 15 MeV neutrons; photoneutron cross sections for /sup 15/N; neutron radiative capture; Lane-model analysis of (p,p) and (n,n) scattering on the even tin isotopes; neutron scattering cross sections for /sup 181/Ta, /sup 197/Au, /sup 209/Bi, /sup 232/Th, and /sup 238/U inferred from proton scattering and charge exchange cross sections; neutron-induced fission cross sections of /sup 245/Cm and /sup 242/Am; fission neutron multiplicities for /sup 245/Cm and /sup 242/Am; the transport of 14 MeV neutrons through heavy materials 150 < A < 208; /sup 249/Cm energy levels from measurement of thermal neutron capture gamma rays; /sup 231/Th energy levels from neutron capture gamma ray and conversion electron spectroscopy; new measurements of conversion electron binding energies in berkelium and californium; nuclear level densities; relative importance of statistical vs. valence neutron capture in the mass-90 region; determination of properties of short-lived fission products; fission yield of /sup 87/Br and /sup 137/I from 15 nuclei ranging from /sup 232/Th to /sup 249/Cf; evaluation of charged particle data for the ECPL library; evaluation of secondary charged-particle energy and angular distributions for ENDL; and evaluated nuclear structure libraries derived from the table of isotopes. (GHT)

Struble, G.L.; Haight, R.C.

1981-03-01T23:59:59.000Z

105

Laser Inertial Fusion-based Energy: Neutronic Design Aspects of a Hybrid Fusion-Fission Nuclear Energy System  

E-Print Network (OSTI)

and Hydroelectric 1.1.3 Nuclear Energy . . . . . . . . .Gain GNEP Global Nuclear Energy Partnership HEU HighlyIn Progress in Nuclear Energy, 17. Pergamon Press, 1986.

Kramer, Kevin James

2010-01-01T23:59:59.000Z

106

Laser Inertial Fusion-based Energy: Neutronic Design Aspects of a Hybrid Fusion-Fission Nuclear Energy System  

E-Print Network (OSTI)

the HTTR project. Nuclear Engineering and Design, 233:163–measurements. Nuclear Engineering Design, 33(92), [87] L.R.in Engineering - Nuclear Engineering in the Graduate

Kramer, Kevin James

2010-01-01T23:59:59.000Z

107

NUCLEAR SCIENCE AND ENGINEERING: 109, 341-349 (1991) Fission Cross-Section Measurements of 247Cm,  

E-Print Network (OSTI)

sections of the even curium iso- topes 242Cm,244Cm,246Cm,and 248Cmwere measured at Rensselaer Polytechnic-section measurement set for the curium isotopes. Einsteinium-254 has a short half-life of 276 days and therefore has a high alpha-particle activity. The fission cross section of such a heavy odd-odd nucleus is interesting

Danon, Yaron

108

Nuclear reactors and the nuclear fuel cycle  

SciTech Connect

According to the author, the first sustained nuclear fission chain reaction was not at the University of Chicago, but at the Oklo site in the African country of Gabon. Proof of this phenomenon is provided by mass spectrometric and analytical chemical measurements by French scientists. The U.S. experience in developing power-producing reactors and their related fuel and fuel cycles is discussed.

Pearlman, H

1989-11-01T23:59:59.000Z

109

Uraninite: A 2 Ga spent nuclear fuel from the natural fission reactor at Bangombe in Gabon, West Africa  

SciTech Connect

Uraninites from the Bangombe natural fission reactor (RZB) and normal uranium-ore occur as fine veins in the sandstone host-rock as well as altered, broken, and slightly displaced grains in an illitic matrix, and in nodules and veins of solid bitumen. Inclusions of galena, (Y,Gd)-rich phosphates, a Pb-oxide and a Ti-oxide? were observed. Uraninites just below RZB were partially altered to a uranyl-sulfate. Three generations of uraninite were identified based on their PbO-contents of 8--11.06 wt%, 6 wt% (the largest population), and a younger generation with 3 wt%. Diffusional loss of Pb is indicated by the presence of a Pb-oxide at the interface to the uraninites. The behavior of the metallic fission products, incompatible with the uraninite structure, may mimic the behavior of Pb in these uraninites. The averaged impurity-content ranges from 4.29 to 6.89 wt%, and consists mainly of SiO{sub 2}, TiO{sub 2}, ZrO{sub 2}, FeO, CaO, Al{sub 2}O{sub 3} and P{sub 2}O{sub 5}. The averaged content of Y{sub 2}O{sub 3} and the Ln`s is less than 0.78 wt% and there is a scattered positive correlation with P{sub 2}O{sub 5}. The content of Y + Ln`s is generally highest in the uraninites from RZB. Uraninite hydration and the formation of uranopelite/zippeite have caused complete loss of Y and the Ln`s. The analytical results indicate that Y and the Ln`s, which are high yield fission products, may be released from uraninite during alteration in the presence of P.

Jensen, K.A. [Aarhus Univ. (Denmark). Dept. of Earth Sciences; Ewing, R.C. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Earth and Planetary Sciences; Gauthier-Lafaye, F. [Centre National de la Recherche Scientifique, Strasbourg (France). Centre de Geochemie de la Surface

1997-12-31T23:59:59.000Z

110

Global nuclear power supply chains and the rise of China's nuclear industry ; Nuclear power supply chains in China : following established rules or redefining the industry? ; Rise of China's nuclear industry .  

E-Print Network (OSTI)

??China has embarked on a massive expansion of nuclear power that may fundamentally change the global nuclear industry, for better or for worse. Some industry… (more)

Metzler, Florian

2012-01-01T23:59:59.000Z

111

Laser Inertial Fusion-based Energy: Neutronic Design Aspects of a Hybrid Fusion-Fission Nuclear Energy System  

E-Print Network (OSTI)

Example of NIF fusion target hohlraum with multiple beamsimilar to those used on NIF. . . . . Overview of LFFHNES Nuclear Energy System NIF National Ignition Facility ODS

Kramer, Kevin James

2010-01-01T23:59:59.000Z

112

Record of Cycling Operation of the Natural Nuclear Reactor in the Oklo/Okelobondo Area in Gabon  

Science Journals Connector (OSTI)

Using selective laser extraction technique combined with sensitive ion-counting mass spectrometry, we have analyzed the isotopic structure of fission noble gases in U-free La-Ce-Sr-Ca aluminous hydroxy phosphate associated with the 2 billion yr old Oklo natural nuclear reactor. In addition to elevated abundances of fission-produced Zr, Ce, and Sr, we discovered high (up to 0.03??cm3???STP/g) concentrations of fission Xe and Kr, the largest ever observed in any natural material. The specific isotopic structure of xenon in this mineral defines a cycling operation for the reactor with 30-min active pulses separated by 2.5 h dormant periods. Thus, nature not only created conditions for self-sustained nuclear chain reactions, but also provided clues on how to retain nuclear wastes, including fission Xe and Kr, and prevent uncontrolled runaway chain reaction.

A. P. Meshik; C. M. Hohenberg; O. V. Pravdivtseva

2004-10-27T23:59:59.000Z

113

Trace Fission Product Ratios for Nuclear Forensics Attribution of Weapons-Grade Plutonium from Fast Breeder Reactor Blankets  

E-Print Network (OSTI)

A nuclear terrorist attack is one of the most serious threats to the national security of the United States, and in the wake of an attack, attribution of responsibility will be of the utmost importance. Plutonium, a by-product in spent nuclear...

Osborn, Jeremy

2014-08-13T23:59:59.000Z

114

U.S. Department of Energy Office of Nuclear Energy, Science and Technology  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

One the cover: One the cover: Albert Einstein (1879-1955) U.S. Department of Energy Office of Nuclear Energy, Science and Technology Washington, D.C. 20585 The History of Nuclear Energy Table of Contents Preface ................................................................... 1 Introduction .......................................................... 3 The Discovery of Fission ...................................... 4 The First Self-Sustaining Chain Reaction ............ 5 The Development of Nuclear Energy for Peaceful Applications ..................................... 7 Chronology of Nuclear Research and Development, 1942-1994 .................................... 13 Selected References ............................................. 23 Glossary ..............................................................

115

Neutronics for critical fission reactors and subcritical fission in hybrids  

SciTech Connect

The requirements of future innovative nuclear fuel cycles will focus on safety, sustainability and radioactive waste minimization. Critical fast neutron reactors and sub-critical, external source driven systems (accelerator driven and fusion-fission hybrids) have a potential role to meet these requirements in view of their physics characteristics. This paper provides a short introduction to these features.

Salvatores, Massimo [CEA-Cadarache, DEN-Dir, Bat. 101, St-Paul-Lez-Durance 13108 (France)

2012-06-19T23:59:59.000Z

116

Analysis of a Nuclear Accident: Fission and Activation Product Releases from the Fukushima Daiichi Nuclear Facility as Remote Indicators of Source Identification, Extent of Release, and State of Damaged Spent Nuclear Fuel  

SciTech Connect

Measurements of several radionuclides within environmental samples taken from the Fukushima Daiichi nuclear facility and reported on the Tokyo Electric Power Company website following the recent tsunami-initiated catastrophe were evaluated for the purpose of identifying the source term, reconstructing the release mechanisms, and estimating the extent of the release. 136Cs/137Cs and 134Cs/137Cs ratios identified Units 1-3 as the major source of radioactive contamination to the surface soil close to the facility. A trend was observed between the fraction of the total core inventory released for a number of fission product isotopes and their corresponding Gibbs Free Energy of formation for the primary oxide form of the isotope, suggesting that release was dictated primarily by chemical volatility driven by temperature and reduction potential within the primary containment vessels of the vented reactors. The absence of any major fractionation beyond volatilization suggested all coolant had evaporated by the time of venting. High estimates for the fraction of the total inventory released of more volatile species (Te, Cs, I) indicated the damage to fuel bundles was likely extensive, minimizing any potential containment due to physical migration of these species through the fuel matrix and across the cladding wall. 238Pu/239,240Pu ratios close-in and at 30 km from the facility indicated that the damaged reactors were the major contributor of Pu to surface soil at the source but that this contribution likely decreased rapidly with distance from the facility. The fraction of the total Pu inventory released to the environment from venting units 1 and 3 was estimated to be ~0.003% based upon Pu/Cs isotope ratios relative to the within-reactor modeled inventory prior to venting and was consistent with an independent model evaluation that considered chemical volatility based upon measured fission product release trends. Significant volatile radionuclides within the spent fuel at the time of venting but not as yet observed and reported within environmental samples are suggested as potential analytes of concern for future environmental surveys around the site.

Schwantes, Jon M.; Orton, Christopher R.; Clark, Richard A.

2012-09-10T23:59:59.000Z

117

MODELING AND FISSION CROSS SECTIONS FOR AMERICIUM.  

SciTech Connect

This is the final report of the work performed under the LANL contract on the modeling and fission cross section for americium isotopes (May 2004-June 2005). The purpose of the contract was to provide fission cross sections for americium isotopes with the nuclear reaction model code EMPIRE 2.19. The following work was performed: (1) Fission calculations capability suitable for americium was implemented to the EMPIRE-2.19 code. (2) Calculations of neutron-induced fission cross sections for {sup 239}Am to {sup 244g}Am were performed with EMPIRE-2.19 for energies up to 20 MeV. For the neutron-induced reaction of {sup 240}Am, fission cross sections were predicted and uncertainties were assessed. (3) Set of fission barrier heights for each americium isotopes was chosen so that the new calculations fit the experimental data and follow the systematics found in the literature.

ROCHMAN, D.; HERMAN, M.; OBLOZINSKY, P.

2005-05-01T23:59:59.000Z

118

Italian hybrid and fission reactors scenario analysis  

SciTech Connect

Italy is a country where a long tradition of studies both in the fission and fusion field is consolidated; nevertheless a strong public opinion concerned with the destination of the Spent Nuclear Fuel hinders the development of nuclear power. The possibility to a severe reduction of the NSF mass generated from a fleet of nuclear reactors employing an hypothetical fusionfission hybrid reactor has been investigated in the Italian framework. The possibility to produce nuclear fuel for the fission nuclear reactors with the hybrid reactor was analyzed too.

Ciotti, M.; Manzano, J.; Sepielli, M. [ENEA CR Frascati, Via Enrico Fermi, 45, 00044, Frascati, Roma (Italy); ENEA CR casaccia, Via Anguillarese, 301, 00123, Santa Maria di Galeria, Roma (Italy)

2012-06-19T23:59:59.000Z

119

Localization of a myosin heavy chain-like polypeptide to Drosophila nuclear pore complexes  

Science Journals Connector (OSTI)

...that is associated with the nuclear envelope. Further immuno...of an ATPase activity to the nuclear pore complex (1-5) as well...recent evidence dem- onstrating energy requirements for specific nuclear protein import in cell-free...

M Berrios; P A Fisher; E C Matz

1991-01-01T23:59:59.000Z

120

Preliminary research of health and environmental impacts and greenhouse gas emission from coal-fired power and nuclear power chains in China  

Science Journals Connector (OSTI)

The present paper treats health, environmental impacts and greenhouse gas emission resulting from both the coal-fired power chain and nuclear power chain in China. The nuclear power chain resulted in adverse health impacts 3-4 orders of magnitude lower than those from the coal-fired power chain, also radiological emissions were 1-2 orders of magnitude lower. Estimated greenhouse gas emission factors amount to 40 fold. The coal-fired power chain is considered to be one of the major sources of environmental pollution in China and rapid expansion of nuclear power in the country promises to be one of the primary ways of mitigating environmental pollution and reducing greenhouse gas emission. At the same time, of course, it is also necessary to increase the energy conversion efficiency of coal as a fuel and to minimise pollutant discharge.

Pan Ziqiang; Chen Zhuzhou; Zhu Zhiming; Xiu Binglin; Ma Zhonghai; Hao Jianzhong; He Huimin

1999-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "nuclear fission chain" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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121

Superfluid dynamics of 258Fm fission  

E-Print Network (OSTI)

Theoretical description of nuclear fission remains one of the major challenges of quantum many-body dynamics. The slow, mostly adiabatic motion through the fission barrier is followed by a fast, non-adiabatic descent of the potential between the fragments. The latter stage is essentially unexplored. However, it is crucial as it generates most of the excitation energy in the fragments. The superfluid dynamics in the latter stage of fission is obtained with the time-dependent Hartree-Fock theory including BCS dynamical pairing correlations. The fission modes of the 258Fm nucleus are studied. The resulting fission fragment characteristics show a good agreement with experimental data. Quantum shell effects are shown to play a crucial role in the dynamics and formation of the fragments. The importance of quantum fluctuations beyond the independent particle/quasi-particle picture is underlined and qualitatively studied.

Scamps, Guillaume; Lacroix, Denis

2015-01-01T23:59:59.000Z

122

Energy partition in nuclear fission  

Science Journals Connector (OSTI)

A scission point model (two spheroid model TSM) including semi-empirical, temperature-dependent shell correction energies for deformed fragments at scission is presented. It has been used to describe the mass-...

A. Ruben; H. Märten; D. Seeliger

1991-01-01T23:59:59.000Z

123

Electric Power from Nuclear Fission  

Science Journals Connector (OSTI)

...Institute of Technology, Cambridge...Institute of Technology, Cambridge...types under development. Attention...oil, and gas-now known...through a turbine driving an...Reactor development authorities...and the gas-cooled fast-breeder...reactor technology already developed...

Manson Benedict

1971-01-01T23:59:59.000Z

124

Advanced modeling of prompt fission neutrons  

SciTech Connect

Theoretical and numerical studies of prompt fission neutrons are presented. The main results of the Los Alamos model often used in nuclear data evaluation work are reviewed briefly, and a preliminary assessment of uncertainties associated with the evaluated prompt fission neutron spectrum for n (0.5 MeV)+{sup 239}Pu is discussed. Advanced modeling of prompt fission neutrons is done by Monte Carlo simulations of the evaporation process of the excited primary fission fragments. The successive emissions of neutrons are followed in the statistical formalism framework, and detailed information, beyond average quantities, can be inferred. This approach is applied to the following reactions: {sup 252}Cf (sf), n{sub th} + {sup 239}Pu, n (0.5 MeV)+{sup 235}U, and {sup 236}Pu (sf). A discussion on the merits and present limitations of this approach concludes this presentation.

Talou, Patrick [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

125

Modeling Fission Product Sorption in Graphite Structures  

SciTech Connect

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

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

2013-04-08T23:59:59.000Z

126

Electroplating method for producing ultralow-mass fissionable deposits  

DOE Patents (OSTI)

A method for producing ultralow-mass fissionable deposits for nuclear reactor dosimetry is described, including the steps of holding a radioactive parent until the radioactive parent reaches secular equilibrium with a daughter isotope, chemically separating the daughter from the parent, electroplating the daughter on a suitable substrate, and holding the electroplated daughter until the daughter decays to the fissionable deposit.

Ruddy, Francis H. (Monroeville, PA)

1989-01-01T23:59:59.000Z

127

E-Print Network 3.0 - absolute thermal fission Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

- Department of Geology and Geophysics, Yale University; Garver, John I. - Department of Geology, Union College Collection: Geosciences 28 Nuclear fission time measurements as a...

128

Nuclear power plants: structure and function  

SciTech Connect

Topics discussed include: steam electric plants; BWR type reactors; PWR type reactors; thermal efficiency of light water reactors; other types of nuclear power plants; the fission process and nuclear fuel; fission products and reactor afterheat; and reactor safety.

Hendrie, J.M.

1983-01-01T23:59:59.000Z

129

DOE Science Showcase - Fission Theory | OSTI, US Dept of Energy, Office of  

Office of Scientific and Technical Information (OSTI)

Fission Theory Fission Theory A predictive theory of nuclear fission has eluded physicists since 1939. Because understanding the fission process is crucial for many areas of scientific research, including particle systems, the development of carbon-free energy and to national security, much work continues at the Department of Energy (DOE) to understand fission's inherent complexity. Today, scientists are performing new experiments and using both microscopic and macroscopic-microscopic models of fission to help them in this quest. Read more about remarkable advances in the Department's fission theory research In the OSTI Collections: Fission Theory by Dr. William Watson, Physicist, OSTI staff. Image Credit: Los Alamos National Laboratory Additional Links of Interest Office of Nuclear Energy, DOE

130

Fission, Fusion Materials Facility  

NLE Websites -- All DOE Office Websites (Extended Search)

is shown in illustration. Materials are the immediate priority of both the fission and fusion communities. Extending the lifetime of the current fleet of light water reactors...

131

Status of fission yield evaluations  

SciTech Connect

Very few yield compilations are also evaluations, and very few contain an extensive global library of measured data and extensive models for unmeasured data. The earlier U.K. evaluations and US evaluations were comparable up to the retirements of the primary evaluators. Only the effort in the US has been continued and expanded. The previous U.K. evaluations have been published. In this paper we summarize the current status of the US evaluation, philosophy, and various integral yield tests for 34 fissioning nuclides at one or more neutron incident energies and/or for spontaneous fission. Currently there are 50 yield sets and for each we have independent and cumulative yields and uncertainties for approximately 1100 fission products. When finalized, the recommended data will become part of the next version of the US Evaluated Nuclear Data File (ENDF/B-VI). The complete set of data, including the basic input of measured yields, will be issued as a sequel to the General Electric evaluation reports (better known by the authors' names: Rider - or earlier - Meek and Rider). 16 references.

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

1983-01-01T23:59:59.000Z

132

Nuclear Power Technology: A Mandate for Change  

Science Journals Connector (OSTI)

Technical Paper / NSF Workshop on the Research Needs of the Next Generation Nuclear Power Technology / Fission Reactor

Kunmo Chung; George A. Hazelrigg

133

Seaborg Announces Fissionable Neptunium  

Science Journals Connector (OSTI)

Seaborg Announces Fissionable Neptunium ... The discovery of a fissionable isotope of neptunium was announced by Glenn T. Seaborg, professor of chemistry at the University of California, at a meeting of the California Section of the AMERICAN CHEMICAL SOCIETY on October 14. ...

1946-10-25T23:59:59.000Z

134

Fusion-Fission for Superheavy (Z{approx}110-126) and Super-Superheavy (Z{approx}160-180) Nuclear Systems  

SciTech Connect

Low-energy damped collisions of very heavy nuclei (238U+238U, 232Th+250Cf and 238U+248Cm) are investigated within a realistic model based on multi-dimensional Langevin equations. Large charge and mass transfer was found in these reactions due to the inverse (anti-symmetrizing) quasi-fission process leading to formation of survived superheavy long-lived neutron-rich nuclei. In many events the lifetime of the composite system consisting of two touching nuclei (giant quasi-atoms) turns out to be rather long; sufficient for spontaneous positron formation from super-strong electric field, a fundamental QED process.

Greiner, Walter [Frankfurt Institute for Advanced Studies, J.W. Goethe-Universitaet, Frankfurt (Germany); Zagrebaev, Valery [Flerov Laboratory of Nuclear Reaction, JINR, Dubna, 141980, Moscow region (Russian Federation)

2006-08-14T23:59:59.000Z

135

Full-energy-chain greenhouse-gas emissions: a comparison between nuclear power, hydropower, solar power and wind power  

Science Journals Connector (OSTI)

Fair comparison of the climate impacts from different energy sources can be made only by accounting for the emissions of all relevant greenhouse gases (GHGs) from the full energy chain (FENCH) of the energy sources. FENCH-GHG emission factors of most of the non-fossil fuel energies are lower than those of the fossil fuels that are in the range of 500-1200 g CO2/kW h(e). The improvement rates concerning their CO2-to-energy ratios of OECD countries and some developing countries are discussed, showing the low performance of the latter from 1965-1996. Detailed FENCH-GHG systems analyses are given for nuclear power, hydropower, and wind and solar power. The FENCH-GHG emission factor of nuclear power is 8.9 g CO2-equiv./kW h(e) and applies to light-water nuclear power plants. The main contributions are from milling, conversion of lower-grade ore, enrichment, construction and operation of the power plant, and reprocessing (if relevant). For hydropower an emission factor is reported of 16 g CO2-equiv./kW h(e) for the best investigated flat-area cold climate power plants. The main, biogenic, emission source is the water reservoir. The information on high-altitude alpine reservoir-type and run-of- river hydropower generation is limited. These plants could probably have emission factors in the low range of 5-10 g CO2-equiv./kW h(e). The FENCH CO2-equivalent emission factors of wind power systems are in the order of 15 g CO2-equiv./kW h(e). The main source is associated with the materials for the turbine and for its foundation. Solar PV and solar thermal power are in an intermediate range their current values are 100-200 and 50-80g CO2-equiv./kW h(e), respectively. GHG emissions are mainly from silicon, which dominates the PV market.

Joop F. van de Vate

2002-01-01T23:59:59.000Z

136

Nuclear Waste  

Science Journals Connector (OSTI)

Nuclear waste is radioactive material no longer considered valuable...238U, 235U, and 226Ra (where the latter decays to 222Rn gas by emitting an alpha particle) or formed through fission of fissile radioisotopes ...

Rob P. Rechard

2014-01-01T23:59:59.000Z

137

Time dependent particle emission from fission products  

SciTech Connect

Decay heating following nuclear fission is an important factor in the design of nuclear facilities; impacting a variety of aspects ranging from cooling requirements to shielding design. Calculations of decay heat, often assumed to be a simple product of activity and average decay product energy, are complicated by the so called 'pandemonium effect'. Elucidated in the 1970's this complication arises from beta-decays feeding high-energy nuclear levels; redistributing the available energy between betas and gammas. Increased interest in improving the theoretical predictions of decay probabilities has been, in part, motivated by the recent experimental effort utilizing the Total Absorption Gamma-ray Spectrometer (TAGS) to determine individual beta-decay transition probabilities to individual nuclear levels. Accurate predictions of decay heating require a detailed understanding of these transition probabilities, accurate representation of particle decays as well as reliable predictions of temporal inventories from fissioning systems. We will discuss a recent LANL effort to provide a time dependent study of particle emission from fission products through a combination of Quasiparticle Random Phase Approximation (QRPA) predictions of beta-decay probabilities, statistical Hauser-Feshbach techniques to obtain particle and gamma-ray emissions in statistical Hauser-Feshbach and the nuclear inventory code, CINDER.

Holloway, Shannon T [Los Alamos National Laboratory; Kawano, Toshihiko [Los Alamos National Laboratory; Moller, Peter [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

138

Recoil-alpha-fission and recoil-alpha-alpha-fission events observed in the reaction Ca-48 + Am-243  

E-Print Network (OSTI)

Products of the fusion-evaporation reaction Ca-48 + Am-243 were studied with the TASISpec set-up at the gas-filled separator TASCA at the GSI Helmholtzzentrum f\\"ur Schwerionenforschung. Amongst the detected thirty correlated alpha-decay chains associated with the production of element Z=115, two recoil-alpha-fission and five recoil-alpha-alpha-fission events were observed. The latter are similar to four such events reported from experiments performed at the Dubna gas-filled separator. Contrary to their interpretation, we propose an alternative view, namely to assign eight of these eleven decay chains of recoil-alpha(-alpha)-fission type to start from the 3n-evaporation channel 115-288. The other three decay chains remain viable candidates for the 2n-evaporation channel 115-289.

U. Forsberg; D. Rudolph; L. -L. Andersson; A. Di Nitto; Ch. E. Düllmann; J. M. Gates; P. Golubev; K. E. Gregorich; C. J. Gross; R. -D. Herzberg; F. P. Hessberger; J. Khuyagbaatar; J. V. Kratz; K. Rykaczewski; L. G. Sarmiento; M. Schädel; A. Yakushev; S. Åberg; D. Ackermann; M. Block; H. Brand; B. G. Carlsson; D. Cox; X. Derkx; J. Dobaczewski; K. Eberhardt; J. Even; C. Fahlander; J. Gerl; E. Jäger; B. Kindler; J. Krier; I. Kojouharov; N. Kurz; B. Lommel; A. Mistry; C. Mokry; W. Nazarewicz; H. Nitsche; J. P. Omtvedt; P. Papadakis; I. Ragnarsson; J. Runke; H. Schaffner; B. Schausten; Y. Shi; P. Thörle-Pospiech; T. Torres; T. Traut; N. Trautmann; A. Türler; A. Ward; D. E. Ward; N. Wiehl

2015-02-10T23:59:59.000Z

139

Fission of light actinides: Th232(n,f) and Pa231(n,f) reactions  

Science Journals Connector (OSTI)

A model to describe fission on light actinides, which takes into account transmission through a triple-humped fission barrier with absorption, is proposed. The fission probability derived in the WKB approximation within an optical model for fission has been incorporated into the statistical model of nuclear reactions. The complex resonant structure in the first-chance neutron-induced fission cross sections of Th232 and Pa231 nuclei has been reproduced by the proposed model. Consistent sets of parameters describing the triple-humped fission barriers of Th233 and Pa232 have been obtained. The results confirm the attribution of the gross resonant structure in the fission probability of these light actinides to partially damped vibrational states in the second well and undamped vibrational states in the third well of the corresponding fission barriers.

M. Sin; R. Capote; A. Ventura; M. Herman; P. ObložinskÝ

2006-07-27T23:59:59.000Z

140

New fission fragment distributions and r-process origin of the rare-earth elements  

E-Print Network (OSTI)

Neutron star (NS) merger ejecta offer a viable site for the production of heavy r-process elements with nuclear mass numbers A > 140. The crucial role of fission recycling is responsible for the robustness of this site against many astrophysical uncertainties, but calculations sensitively depend on nuclear physics. In particular the fission fragment yields determine the creation of 110 140.

Goriely, S; Lemaitre, J -F; Panebianco, S; Dubray, N; Hilaire, S; Bauswein, A; Janka, H -Thomas

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "nuclear fission chain" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Excitation energy dependence of fission in the mercury region  

E-Print Network (OSTI)

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: For 174,180Hg, we predict fission pathways consistent with asymmetric fission at low excitation energies, with the symmetric fission pathway opening very gradually as excitation energy is increased. For 198Hg and 196Po, we expect the nearly-symmetric fission channel to dominate. 210Po shows a preference for a slightly asymmetric pathway at low energies, and a preference for a symmetric pathway at high energies. Conclusions: Our self-consistent theory suggests that excitation energy weakly affects the fission pattern of the nuclei considered. The transition from the asymmetric fission in the proton-rich nuclei to a more symmetric fission in the heavier isotopes is governed by the shell structure of pre-scission configurations.

J. D. McDonnell; W. Nazarewicz; J. A. Sheikh; A. Staszczak; M. Warda

2014-06-26T23:59:59.000Z

142

Actinide neutron-induced fission cross section measurements at LANSCE  

SciTech Connect

Fission cross sections of a range of actinides have been measured at the Los Alamos Neutron Science Center (LANSCE) in support of nuclear energy applications in a wide energy range from sub-thermal energies up to 200 MeV. A parallel-plate ionization chamber are used to measure fission cross sections ratios relative to the {sup 235}U standard while incident neutron energies are determined using the time-of-flight method. Recent measurements include the {sup 233,238}U, {sup 239-242}Pu and {sup 243}Am neutron-induced fission cross sections. Obtained data are presented in comparison with ex isting evaluations and previous data.

Tovesson, Fredrik K [Los Alamos National Laboratory; Laptev, Alexander B [Los Alamos National Laboratory; Hill, Tony S [INL

2010-01-01T23:59:59.000Z

143

Cross section for the subbarrier fission of {sup 244}Cm  

SciTech Connect

The cross section for {sup 244}Cm fission induced by neutrons of energy in the range between 0.07 eV and 20 keV was measured by using the lead slowing-down spectrometer (LSDS-100) of the Institute for Nuclear Research (Russian Academy of Sciences, Moscow). The parameters of the resonance areas were determined for the lowest eight s-wave neutron resonances, and the respective fission widths were evaluated. Also, the parameters of the intermediate structure in the cross section for the subbarrier fission of {sup 244}Cm nuclei were evaluated. The results were compared with available data and recommendations based on evaluations.

Alekseev, A. A.; Bergman, A. A.; Berlev, A. I.; Koptelov, E. A. [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation); Samylin, B. F.; Svirin, M. I.; Trufanov, A. M.; Fursov, B. I.; Shorin, V. S., E-mail: shorin@ippe.r [Institute of Physics and Power Engineering (Russian Federation)

2010-09-15T23:59:59.000Z

144

Actinide Neutron-Induced Fission Cross Section Measurements At LANSCE  

SciTech Connect

Fission cross sections of a range of actinides have been measured at the Los Alamos Neutron Science Center (LANSCE) in support of nuclear energy applications in a wide energy range from sub thermal energies up to 200 MeV. Parallel-plate ionization chambers are used to measure fission cross sections ratios relative to the {sup 235}U standard while incident neutron energies are determined using the time-of-flight method. Recent measurements include the {sup 233,238}U, {sup 239-242}Pu and {sup 243}Am neutron-induced fission cross sections. Obtained data are presented in comparison with existing evaluations and previous data.

Tovesson, F.; Laptev, A. B. [Los Alamos National Laboratory, Los Alamos NM 87545 (United States); Hill, T. S. [Idaho National Laboratory, Idaho Falls ID 83415 (United States)

2011-06-01T23:59:59.000Z

145

November 9, 2003 21:47 WSPC/Trim Size: 9in x 6in for Proceedings royer-nanuf03 FISSION BARRIERS  

E-Print Network (OSTI)

Institute of Physics and Nuclear Engineering, P.O. Box MG-6, RO-76900, Bucharest, Romania E-mail: rgherg-fission of heavy systems and fragmentation have renewed interest in investigating the fusion-like fission valley

Paris-Sud XI, Université de

146

Features of a subcritical nuclear reactor  

Science Journals Connector (OSTI)

Abstract A subcritical nuclear reactor is a device where the nuclear-fission chain reaction is initiated and maintained using an external neutron source. It is a valuable educational and research tool where in a safe way many reactor parameters can be measured. Here, we have used the six-factor formula to calculate the effective multiplication factor of a subcritical nuclear reactor Nuclear Chicago model 9000. Using the MCNP5 code, a three-dimensional model of the subcritical reactor was developed to estimate the effective multiplication factor, the neutron spectra, and the total and thermal neutron fluences along the radial and axial axis. The MCNP5 results of the effective multiplication factor were compared with those obtained from the six-factor formula. The effective dose and the Ambient dose equivalent, at three sites outside the reactor, were estimated; the Ambient dose equivalent was also measured and compared with the calculated values.

Hector Rene Vega-Carrillo; Isvi Ruben Esparza-Garcia; Alvaro Sanchez

2015-01-01T23:59:59.000Z

147

Fission product studies in the symmetric mass region  

SciTech Connect

Fission yields can be determined by radiochemical or mass spectrometric techniques. Mass spectrometry can provide more accurate data, particularly in the symmetric mass region where the probability of fission is low and uncertainties in isometric ratios occur. Fine structure in the mass distribution can usually only be determined by mass spectrometry. Many of the elements in the valley of symmetry have high ionization potentials and are therefore difficult to measure by solid source mass spectrometry. Analytical techniques have been developed to provide the sensitivity required to measure the small sample sizes available in fission product studies. Cumulative fission yields for ruthenium, palladium, cadmium, tin, and tellurium have been measured by mass spectrometry for the thermal and epicadmium fission of {sup 233}U and for thermal and epicadmium fission of {sup 239}Pu. These fission yields, which span the mass range 101 {le} A {le} 130, can be combined to give a mass yield curve for {sup 235}U in the valley region, which is symmetrical about A = 116.8 and exhibits fine structure in the mass 113 to 114 region. Fine structure in {sup 233}U is also present at mass 111. Mass spectrometric determinations of the fission yields of uranium ore at the Oklo mine site in Gabon enable the nuclear parameters of this natural reactor to be evaluated. This in turn enables the amounts of fission products produced in the reactor zone and the surrounding rocks enables an assessment to be made of the efficiency of this geological repository for containing radioactive waste. The elemental abundances can be determined by isotope dilution mass spectrometry. Unfortunately, the paucity of good fission yield data available for {sup 238}U by fast neutrons is a severe constraint in this evaluation.

De Laeter, J.R.; Rosman, K.J.R.; Loss, R.D. [Curtin Univ. of Technology, Perth (AU)

1993-05-01T23:59:59.000Z

148

Uncertainties analysis of fission fraction for reactor antineutrino experiments using DRAGON  

E-Print Network (OSTI)

Rising interest in nuclear reactors as a source of antineutrinos for experiments motivates validated, fast, and accessible simulation to predict reactor rates. First, DRAGON was developed to calculate the fission rates of the four most important isotopes in fissions,235U,238U,239Pu and141Pu, and it was validated for PWRs using the Takahama benchmark. The fission fraction calculation function was validated through comparing our calculation results with MIT's results. we calculate the fission fraction of the Daya Bay reactor core, and compare its with those calculated by the commercial reactor simulation program SCIENCE, which is used by the Daya Bay nuclear power plant, and the results was consist with each other. The uncertainty of the antineutrino flux by the fission fraction was studied, and the uncertainty of the antineutrino flux by the fission fraction simulation is 0.6% per core for Daya Bay antineutrino experiment.

X. B. Ma; L. Z. Wang; Y. X. Chen; W. L. Zhong; F. P. An

2014-05-27T23:59:59.000Z

149

Realistic fission model and the r-process in neutron star mergers  

SciTech Connect

About half of heavy elements are considered to be produced by the rapid neutron-capture process, r-process. The neutron star merger is one of the viable candidates for the astrophysical site of r-process nucleosynthesis. Nuclear fission reactions play an important role in the r-process of neutron star mergers. However theoretical predictions about fission properties of neutron-rich nuclei have some uncertainties. Especially, their fission fragment distributions are totally unknown and the phenomenologically extrapolated distribution was often applied to nucleosynthesis calculations. In this study, we have carried out r-process nucleosynthesis calculations based upon new theoretical estimates of fission fragment distributions. We discuss the effects on the r-process in neutron star mergers from the nuclear fission of heavy neutron-rich actinide elements. We also discuss how variations in the fission fragment distributions affect the abundance pattern.

Shibagaki, S.; Kajino, T. [Department of Astronomy, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan and National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Chiba, S. [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo, 152-8850 (Japan); Mathews, G. J. [Center for Astrophysics, Department of Physics, University of Notre Dame, IN 46556, U.S.A. and National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

2014-05-09T23:59:59.000Z

150

Fiscal year 1985 Department of Energy authorization (nuclear fission R and D and waste management). Volume IV. Hearings before the Subcommittee on Energy Research and Production of the Committee on Science and Technology, US House of Representatives, Ninety-Eighth Congress, Second Session, February 7, 8, 9, 1984  

SciTech Connect

Volume IV of the DOE authorization hearings covers material relating to research and development on nuclear fission and on waste management during three days of testimony. The 29 witnesses included nuclear scientists in both the private and public sector, as well as specialists in energy policy, electric power, and the nuclear industry. Among the issues covered were the distribution of resources for nuclear research to ensure the development of innovative technology, problems within the nuclear industry, regulatory reform, the progress on spent fuel research and development, and funding for the light water reactor extended burnup program. Chairman Lloyd noted the problems associated with a 50% decline in federal funding during the Reagan administration. An appendix with supplemental questions and answers for the record follows the testimony.

Not Available

1984-01-01T23:59:59.000Z

151

The Road to Controlled Nuclear Fusion  

Science Journals Connector (OSTI)

... is one atom of deuterium for every 7,000 atoms of ordinary hydrogen. Second, nuclear fusion does not generate as much radioactive waste as nuclear fission, so storage-a serious ... plants-does not constitute such a serious problem. By contrast with nuclear fission, however, nuclear fusion reactions cannot be sustained by themselves in matter which is in its normal state. ...

L. ARTSIMOVICH

1972-09-01T23:59:59.000Z

152

Group Constants Generation of the Pseudo Fission Products for Fast Reactor Burnup Calculations  

SciTech Connect

The pseudo fission products for the burnup calculations of the liquid metal fast reactor were generated. The cross-section data and fission product yield data of ENDF/B-VI were used for the pseudo fission product data of U-235, U-238, Pu-239, Pu-240, Pu-241, and Pu-242. The pseudo fission product data can be used with the KAFAX-F22 or -E66, which are the MATXS-format libraries for analyses of the liquid metal fast reactor at KAERI and were distributed through the OECD/NEA. The 80-group MATXS-format libraries of the 172 fission products were generated and the burnup chains for generation of the pseudo fission products were prepared.

Gil, Choong-Sup; Kim, Do Heon; Chang, Jonghwa [Korea Atomic Energy Research Institute, 150 Dukjin-dong, Yusung-gu, Taejon (Korea, Republic of)

2005-05-24T23:59:59.000Z

153

Using Quasi-Monoenergetic Photon Sources To Probe Photo-Fission Resonances  

SciTech Connect

We present preliminary results of photo-fission measurements of uranium isotopes with the quasi-monoenergetic gamma-ray source, HIGS. The measurements were performed to search for photo-fission resonances. We discuss potential applications to use photo-fission resonances to identify special nuclear material in cargo containers. We discuss the importance of quasi-monoenergetic gamma-ray sources for this kind of application.

Johnson, Micah S.; Hall, James M.; McNabb, Dennis P. [Lawrence Livermore National Laboratory, Livermore CA 94550 (United States); Tuffley, Michael J. [San Jose State University, San Jose CA 95192 (United States); Ahmed, Mohammed W.; Stave, Sean; Weller, Henry R. [Duke University, Durham NC 27708 (United States); Karwowski, Hugon; Thompkins, Jeromy [University of North Carolina, Chapel Hill NC 27599 (United States)

2011-06-01T23:59:59.000Z

154

Fission fragment mass distributions in reactions forming the Fr213 compound nucleus  

Science Journals Connector (OSTI)

The fission fragment mass angle correlations and mass ratio distributions have been investigated for the two systems O16+Au197 and Al27+W186, leading to the same compound nucleus Fr213 around the Coulomb barrier energies. Systematic analysis of the variance of the mass distributions as a function of temperature and angular momentum suggests true compound nuclear fission for both the reactions, indicating the absence of nonequilibrium fission processes.

S. Appannababu; S. Mukherjee; B. K. Nayak; R. G. Thomas; P. Sugathan; A. Jhingan; E. Prasad; D. Negi; N. N. Deshmukh; P. K. Rath; N. L. Singh; R. K. Choudhury

2011-03-10T23:59:59.000Z

155

Event-by-Event Simulation of Induced Fission  

SciTech Connect

We are developing a novel code that treats induced fission by statistical (or Monte-Carlo) simulation of individual decay chains. After its initial excitation, the fissionable compound nucleus may either deexcite by evaporation or undergo binary fission into a large number of fission channels each with different energetics involving both energy dissipation and deformed scission prefragments. After separation and Coulomb acceleration, each fission fragment undergoes a succession of individual (neutron) evaporations, leading to two bound but still excited fission products (that may further decay electromagnetically and, ultimately, weakly), as well as typically several neutrons. (The inclusion of other possible ejectiles is planned.) This kind of approach makes it possible to study more detailed observables than could be addressed with previous treatments which have tended to focus on average quantities. In particular, any type of correlation observable can readily be extracted from a generated set of events. With a view towards making the code practically useful in a variety of applications, emphasis is being put on making it numerically efficient so that large event samples can be generated quickly. In its present form, the code can generate one million full events in about 12 seconds on a MacBook laptop computer. The development of this qualitatively new tool is still at an early stage and quantitative reproduction of existing data should not be expected until a number of detailed refinement have been implemented.

Vogt, R; Randrup, J

2007-12-13T23:59:59.000Z

156

Symmetric and asymmetric fission modes in proton-induced fission at 660 MeV of {sup 238}U  

SciTech Connect

Fission product cross sections of intermediate-energy fission of {sup 238}U were used in order to construct the charge and mass yield distributions. Enriched target of {sup 238}U was irradiated by proton beam with energy 660 MeV for several hours at the LNP Phasotron, Joint Institute for Nuclear Research (JINR), Dubna, Russia. The charge distribution of the fission fragments was analyzed for calculation of isobaric cross sections. The mass yield curves were expanded into symmetric and asymmetric components according multimodal fission approach. The fissility values of actinides were calculated at given proton energy. The obtained results have been compared to the same data for targets {sup 237}Np and {sup 241}Am.

Balabekyan, A. R., E-mail: balabekyan@ysu.am; Karapetyan, G. S. [Yerevan State University (Armenia); Demekhina, N. A.; Adam, J. [JINR (Russian Federation); Katovsky, K. [Czech Technical University in Prague, Department of Nuclear Reactors (Czech Republic)

2010-11-15T23:59:59.000Z

157

Science based stockpile stewardship, uncertainty quantification, and fission fragment beams  

SciTech Connect

Stewardship of this nation's nuclear weapons is predicated on developing a fundamental scientific understanding of the physics and chemistry required to describe weapon performance without the need to resort to underground nuclear testing and to predict expected future performance as a result of intended or unintended modifications. In order to construct more reliable models, underground nuclear test data is being reanalyzed in novel ways. The extent to which underground experimental data can be matched with simulations is one measure of the credibility of our capability to predict weapon performance. To improve the interpretation of these experiments with quantified uncertainties, improved nuclear data is required. As an example, the fission yield of a device was often determined by measuring fission products. Conversion of the measured fission products to yield was accomplished through explosion code calculations (models) and a good set of nuclear reaction cross-sections. Because of the unique high-fluence environment of an exploding nuclear weapon, many reactions occurred on radioactive nuclides, for which only theoretically calculated cross-sections are available. Inverse kinematics reactions at CARIBU offer the opportunity to measure cross-sections on unstable neutron-rich fission fragments and thus improve the quality of the nuclear reaction cross-section sets. One of the fission products measured was {sup 95}Zr, the accumulation of all mass 95 fission products of Y, Sr, Rb and Kr (see Fig. 1). Subsequent neutron-induced reactions on these short lived fission products were assumed to cancel out - in other words, the destruction of mass 95 nuclides was more or less equal to the production of mass 95 nuclides. If a {sup 95}Sr was destroyed by an (n,2n) reaction it was also produced by (n,2n) reactions on {sup 96}Sr, for example. However, since these nuclides all have fairly short half-lives (seconds to minutes or even less), no experimental nuclear reaction cross-sections exist, and only theoretically modeled cross-sections are available. Inverse kinematics reactions at CARIBU offer the opportunity, should the beam intensity be sufficient, to measure cross-sections on a few important nuclides in order to benchmark the theoretical calculations and significantly improve the nuclear data. The nuclides in Fig. 1 are prioritized by importance factor and displayed in stoplight colors, green the highest and red the lowest priority.

Stoyer, M A; McNabb, D; Burke, J; Bernstein, L A; Wu, C Y

2009-09-14T23:59:59.000Z

158

Use of Organometallic Polymers for Pre-Heat Shields for Targets in Inertial-Confinement Nuclear Fusion  

Science Journals Connector (OSTI)

Nuclear fusion, the energy process operating in the sun ... radioactive wastes associated with nuclear fission. Harnessing nuclear fusion, however, has proven to be a...

John E. Sheats; Fred Hessel; Louis Tsarouhas…

1985-01-01T23:59:59.000Z

159

Nuclear evaporation process with simultaneous multiparticle emission  

E-Print Network (OSTI)

The nuclear evaporation process is reformulated by taking into account simultaneous multiparticle emission from a hot compound nucleus appearing as an intermediate state in many nuclear reaction mechanisms. The simultaneous emission of many particles is particularly relevant for high excitation energy of the compound nucleus.These channels are effectively open in competition with the single particle emissions and fission in this energy regime. Indeed, the inclusion of these channels along the decay evaporating chain shows that the yield of charged particles and occurrence of fission are affected by these multiparticle emission processes of the compounded nucleus, when compared to the single sequential emission results. The effect also shows a qualitative change in the neutron multiplicity of different heavy compound nucleus considered. This should be an important aspect for the study of spallation reaction in Acceleration Driven System (ADS) reactors. The majority of neutrons generated in these reactions come from the evaporation stage of the reaction, the source of neutron for the system. A Monte Carlo simulation is employed to determine the effect of these channels on the particle yield and fission process. The relevance of the simultaneous particle emission with the increasing of excitation energy of the compound nucleus is explicitly shown.

Leonardo P. G. De Assis; Sergio B. Duarte; Bianca M. Santos

2012-08-07T23:59:59.000Z

160

Absence of entrance channel effects in fission fragment anisotropies of the Fr215 compound nucleus  

Science Journals Connector (OSTI)

Fission fragment angular distributions have been measured for the reactions B11+Pb204 and O18+Au197, both leading to the same compound nucleus Fr215 at near barrier energies. The measured fission fragment anisotropies as a function of Ec.m./VB are found to be consistent with the predictions of the standard saddle point statistical model (SSPM) for both the systems, suggesting the absence of entrance channel effects on fission fragment anisotropies even though the entrance channel mass asymmetries for both these systems fall on either side of the Bussinaro-Gallone critical mass asymmetry. The consistency of the present results with SSPM predictions can be understood within the framework of the pre-equilibrium fission model where fission before K equilibration is severely inhibited by the high values of ratios of fission barrier height to nuclear temperature.

S. Appannababu; S. Mukherjee; N. L. Singh; P. K. Rath; G. Kiran Kumar; R. G. Thomas; S. Santra; B. K. Nayak; A. Saxena; R. K. Choudhury; K. S. Golda; A. Jhingan; R. Kumar; P. Sugathan; Hardev Singh

2009-08-12T23:59:59.000Z

Note: This page contains sample records for the topic "nuclear fission chain" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Stability of 114298 Against Fission  

Science Journals Connector (OSTI)

The formalism of Siemens and Bethe concerning the stability of 114298 gives different conclusions depending on the mass formula used in obtaining the fissionability parameter.

Cheuk-Yin Wong

1967-08-07T23:59:59.000Z

162

Lecture notes for introduction to nuclear engineering 101  

SciTech Connect

The lecture notes for introductory nuclear engineering are provided for Department of Energy personnel that are recent graduates, transfers from non-nuclear industries, and people with minimum engineering training. The material assumes a knowledge of algebra and elementary calculus. These notes support and supplement a three-hour lecture. The reader is led into the subject from the familiar macroscopic world to the microscopic world of atoms and the parts of atoms called elementary particles. Only a passing reference is made to the very extensive world of quarks and tansitory particles to concentrate on those associated with radioactivity and fission. The Einsteinian truth of mass-energy equivalence provides an understanding of the forces binding a nucleus with a resulting mass defect that results in fusion at one end of the mass spectrum and fission at the other. Exercises are provided in calculating the energy released in isotopic transformation, reading and understanding the chart of the nuclides. The periodic table is reviewed to appreciate that the noble elements are produced by quantum mechanical shell closings. Radioactive decay is calculated as well as nuclear penetration and shielding. The geometric attenuation of radiation is studied for personal protection; the use of shielding materials for radiation protection is presented along with the buildup factor that renders the shielding less effective than might be supposed. The process of fission is presented along with the fission products and energies produced by fission. The requirements for producing a sustained chain reactor are discussed. The lecture ends with discussions of how radiation and dose is measured and how dose is converted to measures of the damage of radiation to our bodies.

Fullwood, R.; Cadwell, J.

1992-03-01T23:59:59.000Z

163

PASSAGE OF FISSION PRODUCTS THROUGH THE SKIN OF TUNA  

E-Print Network (OSTI)

which varies in rate depending on a number of factors. The rate of penetration of sodium chloride is low · · 3 Cesium- 137 · · · . 3 Ruthenium - 106 3 Penetration of isotopes into muscle tissue Strontium-89 4 the penetration of radioactive strontium, cesium, and ruthenium common products of nuclear fission, through

164

Browse by Discipline -- E-print Network Subject Pathways: Fission...  

Office of Scientific and Technical Information (OSTI)

Fission and Nuclear Technologies Go to Research Groups Preprints Provided by Individual Scientists: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z Go back to Individual...

165

Some Comments on the Mechanism of Fission  

E-Print Network (OSTI)

MECHANISFI OF FISSION Glenn T. Seaborg July 25, 1951 T h i sITCHANISM OF FISSION Glenn T. Seaborg and ~ e ~ a r t m e nMECHANISM OF FISSION Glenn T. Seaborg Radiation Laboratory

Seaborg, Glenn T.

1951-01-01T23:59:59.000Z

166

Coordinate-Dependent Mass and the Validity of the WKB Approximation in Fission Barrier Penetration Calculations  

Science Journals Connector (OSTI)

......associated with collective nuclear motion may vary substantially...Consequently, the energy denomi- nator appearing...centers of mass of the two nuclear halves, while R3 is...length or half of the nuclear elongation along the fission axis. The potential energy and the mass plotted......

Krishna Kumar

1990-09-01T23:59:59.000Z

167

Nuclear Reactor (atomic reactor)  

Science Journals Connector (OSTI)

A nuclear reactor splits Uranium or Plutonium nuclei, and the...235 is fissionable but more than 99% of the naturally occurring Uranium is U238 that makes enrichment mandatory. In some reactors U238 and Thorium23...

2008-01-01T23:59:59.000Z

168

Precise Barriers and Shell Effects: a New Inroad to Fission Saddle Point Spectroscopy  

E-Print Network (OSTI)

Fission excitation functions have been measured for a chain of neighboring compound nuclei, from 207Po to 212Po. We present a new analysis which provides a determination of the fission barriers and ground state shell effects with nearly spectroscopic accuracy. The improved accuracy achieved in this analysis may lead to a future detailed exploration of the saddle mass surface and its spectroscopy. The sensitivity of the fission probabilities on shell effects extends to excitation energies of 150 MeV and negates recent claims for the disappearance of shell corrections due to collective effects.

L. Phair; L. G. Moretto; K. X. Jing; L. Beaulieu; D. Breus; J. B. Elliott; T. S. Fan; Th. Rubehn; G. J. Wozniak

2003-03-06T23:59:59.000Z

169

Cross section for {sup 246}Cm subbarrier fission  

SciTech Connect

The cross section for {sup 246}Cm fission induced by neutrons of energy in the range 0.1 eV-20 keV was measured by the neutron lead slowing-down spectrometer (LSDS-100) of the Institute for Nuclear Research (INR, Russian Academy of Sciences, Moscow). The parameters of the resonance area and of the fission width were evaluated for several low-lying s-wave neutron resonances. The parameters of the intermediate structure in the cross section for the subbarrier fusion of {sup 246}Cm nuclei were found. The results obtained in this way were compared with available experimental data and with recommended evaluated data.

Alekseev, A. A.; Bergman, A. A.; Berlev, A. I.; Koptelov, E. A. [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation); Samylin, B. F.; Trufanov, A. M.; Fursov, B. I.; Shorin, V. S., E-mail: shorin@ippe.r [Institute for Physics and Power Engineering (Russian Federation)

2010-10-15T23:59:59.000Z

170

Nuclear shell effect and collinear tripartition of nuclei  

E-Print Network (OSTI)

A possibility of formation of the three reaction products having comparable masses at the spontaneous fission of $^{252}$Cf is theoretically explored. This work is aimed to study the mechanism leading to observation of the reaction products with masses $M_1=$136---140 and $M_2=$68---72 in coincidence by the FOBOS group in JINR. The same type of ternary fission decay has been observed in the reaction $^{235}$U(n$_{\\rm th}$,fff). The potential energy surface for the ternary system forming a collinear nuclear chain is calculated for the wide range of mass and charge numbers of constituent nuclei. The results of the PES for the tripartition of $^{252}$Cf(sf,fff) shows, that we have favorable dynamical conditions for the formation of fragments with mass combinations of clusters $^{68-70}$Ni with $^{130-132}$Sn and with missing cluster $^{48-52}$Ca.

Nasirov, A K; Tashkhodjaev, R B

2014-01-01T23:59:59.000Z

171

Physics of nuclear reactor safety  

Science Journals Connector (OSTI)

Provides a concise review of the physical aspects of safety of nuclear fission reactors. It covers the developments of roughly the last decade. The introductory chapter contains an analysis of the changes in safety philosophy that are characteristic of the last decade and that have given rise to an increased importance of physical aspects because of the emphasis on passive or natural safety. The second chapter focuses on the basics of reactor safety, identifying the main risk sources and the main principles for a safe design. The third chapter concerns a systematic treatment of the physical processes that are fundamental for the properties of fission chain reacting processes and the control of those processes. Because of the rather specialized nature of the field of reactor physics, each paragraph contains a very concise description of the theory of the phenomenon under consideration, before presenting a review of the developments. Chapter 4 contains a short review of the thermal aspects of reactor safety, restricted to those aspects that are characteristic of the nuclear reactor field, because thermal hydraulics of fission reactors is not principally different from that of other physical systems. In chapter 5 the consequences of the physics treated in the preceding chapters for the dynamics and safety of actual reactors are reviewed. The systematics of the treatment is mainly based on a division of reactors into three categories according to the type of coolant, which to a large extent determines the safety properties of the reactors. The last chapter contains a physical analysis of the Chernobyl accident that occurred in 1986. The reason for an attempt to give a review of this accident, as complete as possible within the space limits set by the editors, is twofold: the Chernobyl accident is the most severe accident in history and physical properties of the reactor played a decisive role, thereby serving as an illustration of the material of the preceding chapters.

H van Dam

1992-01-01T23:59:59.000Z

172

Fission cross section measurements of actinides at LANSCE  

SciTech Connect

Fission cross sections of a range of actinides have been measured at the Los Alamos Neutron Science Center (LANSCE) in support of nuclear energy applications. By combining measurement at two LANSCE facilities, Lujan Center and the Weapons Neutron Research center (WNR), differential cross sections can be measured from sub-thermal energies up to 200 MeV. Incident neutron energies are determined using the time-of-flight method, and parallel-plate ionization chambers are used to measure fission cross sections relative to the {sup 235}U standard. Recent measurements include the {sup 233,238}U, {sup 239,242}Pu and {sup 243}Am neutron-induced fission cross sections. In this paper preliminary results for cross section data of {sup 243}Am and {sup 233}U will be presented.

Tovesson, Fredrik [Los Alamos National Laboratory; Laptev, Alexander B [Los Alamos National Laboratory; Hill, Tony S [INL

2010-01-01T23:59:59.000Z

173

Comprehensive Nuclear Materials  

SciTech Connect

This book encompasses a rich seam of current information on the vast and multidisciplinary field of nuclear materials employed in fission and prototype fusion systems. Discussion includes both historical and contemporary international research in nuclear materials, from Actinides to Zirconium alloys, from the worlds leading scientists and engineers. Synthesizes pertinent current science to support the selection, assessment, validation and engineering of materials in extreme nuclear environments. The work discusses the major classes of materials suitable for usage in nuclear fission, fusion reactors and high power accelerators, and for diverse functions in fuels, cladding, moderator and control materials, structural, functional, and waste materials.

Konings, Dr. Rudy J. M. [European Commission Joint Research Centre; Allen, Todd R. [University of Wisconsin, Madison; Stoller, Roger E [ORNL; Yamanaka, Prof. Shinsuke [Osaka University

2012-01-01T23:59:59.000Z

174

Nuclear Systems Technology | Nuclear Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Advanced Fuel Cycle Systems Criticality Safety Irradiation Experiment Development and Execution Robotics & Remote Systems Engineering and Applications Thermal & Hydraulic Experiments & Analysis Used Nuclear Fuel Storage, Transportation, and Disposal Reactor Technology Nuclear Science Home | Science & Discovery | Nuclear Science | Research Areas | Nuclear Systems Technology SHARE Nuclear Systems Technology Nuclear Systems Technology Image 2 ORNL has had historic involvement in a broad set of nuclear research areas: irradiated materials and isotopes R&D, fission and fusion reactors development, neutron scattering, fuel enrichment, used fuel recycling and disposal, etc. The skills and knowledge required to succeed in these research areas often cultivated core areas of expertise in which ORNL is

175

SciTech Connect: The Microscopic Theory of Fission  

Office of Scientific and Technical Information (OSTI)

Theory of Fission Fission-fragment properties have been calculated for thermal neutron-induced fission on a sup 239Pu target, using constrained Hartree-Fock-Bogoliubov...

176

Nuclear energy: current situation and prospects to 2020  

Science Journals Connector (OSTI)

...Blundell and Fraser Armstrong Nuclear energy: current situation and prospects...stand to improve the economics of nuclear energy still further. Waste volumes...UK's long-term energy needs. nuclear energy|fission|reactor systems...

2007-01-01T23:59:59.000Z

177

Prompt ?-ray production in neutron-induced fission of 239Pu  

Science Journals Connector (OSTI)

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

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

2013-04-11T23:59:59.000Z

178

Neutron Emission in Fission And Quasi-Fission of Hs  

SciTech Connect

Mass and energy distributions of fission-like fragments obtained in the reactions {sup 26}Mg+{sup 248}Cm, {sup 36}S+{sup 238}U and {sup 58}Fe+{sup 208}Pb leading to the formation of {sup 266,274}Hs are reported. From the analysis of TKE distributions for symmetric fragment it was found that at energies below the Coulomb barrier the bimodal fission of {sup 274}Hs, formed in the reaction {sup 26}Mg+{sup 248}Cm, is observed, while in the reaction {sup 36}S+{sup 238}U at these energies the main part of the symmetric fragments arises from the quasi-fission process. At energies above the Coulomb barrier the fusion-fission is a main process leading to the formation of symmetric fragment for the both reactions. In the case of {sup 58}Fe+{sup 208}Pb reaction the quasi-fission process is the main reaction mechanism at all measured energies. The pre- and post-scission neutron multiplicities as a function of the fragment mass have been obtained for all studied reactions.

Itkis, I. M.; Itkis, M. G.; Knyazheva, G. N.; Kozulin, E. M.; Krupa, L. [Flerov Laboratory of Nuclear Reactions, JINR, Dubna (Russian Federation); Hanappe, F. [Universite Libre de Bruxelles, Belgique (Belgium); Dorvaux, O.; Stuttge, L. [Institut de Recherches Subatomiques, Strasbourg (France)

2010-04-30T23:59:59.000Z

179

Odd-even systematics in neutron fission yields of U233 and U235  

Science Journals Connector (OSTI)

An analysis of the distribution of independent yields in neutron induced fission of U233 and U235 revealed a constant enhancement of products with an even number of protons, relative to those with an odd number. This odd-even effect in the proton pairing, related to calculated "normal" yields of elements in fission, constitutes a sawtooth structure with an amplitude of (22±7)% for both U233 and U235 thermal neutron induced fission. The residual neutron pairing effect evident after the emission of prompt neutrons, while it is insignificant (thermal neutron fission products. Its average magnitude is about (8±5)% relative to the "normal" distribution of isotonic yields. In the fission of U235 with fission spectrum neutrons, the proton pairing effect drops to (8±4)%. The odd-even effect is discussed in view of the various mass splits, the excitation energy and potential energy surfaces in the descent from the saddle to the scission configuration.NUCLEAR REACTIONS, FISSION U235(nth, f), U233(nth, f), and U235(nfast, f). Reevaluation of independent fission yields, deduced odd-even yield systematics.

S. Amiel and H. Feldstein

1975-03-01T23:59:59.000Z

180

Fission Thrust sail as booster for high {\\Delta}v fusion based propulsion  

E-Print Network (OSTI)

The fission thrust sail as booster for nuclear fusion-based rocket propulsion for future starships is studied. Some required aspects of these systems such as neutron moderation and sail regeneration are discussed. First order calculations are used together with Monte Carlo simulations to assess system performance. When the fusion rocket has relatively low efficiency (~30%) in converting fusion fuel to a directed exhaust, adding a fission sail is shown to be beneficial for obtainable delta-v. Also, this type of fission-fusion hybrid interstellar propulsion has the potential to improve acceleration. Other advantages are discussed as well.

Ceyssens, Frederik; Driesen, Maarten

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "nuclear fission chain" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
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We encourage you to perform a real-time search of NLEBeta
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181

Office of Nuclear Energy, Science and Technology Executive Summary  

E-Print Network (OSTI)

Office of Nuclear Energy, Science and Technology Executive Summary Mission As we become more in this new century, the benefits of nuclear fission as a key energy source for both the near- and long method of generating energy from nuclear fission in both the United States and the world. A key mission

182

Nuclear magnetic resonance solution structure of hirudin(1–51) and comparison with corresponding three-dimensional structures determined using the complete 65-residue hirudin polypeptide chain  

Science Journals Connector (OSTI)

The three-dimensional structure of the N-terminal 51-residue domain of recombinant hirudin in aqueous solution was determined by 1H nuclear magnetic resonance (NMR) spectroscopy, and the resulting high-quality solution structure was compared with corresponding structures obtained from studies with the intact, 65-residue polypeptide chain of hirudin. On the basis of 580 distance constraints derived from nuclear Overhauser effects and 109 dihedral angle constraints, a group of 20 conformers representing the solution structure of hirudin(1–51) was computed with the program DIANA and energyminimized with a modified version of the program AMBER. Residues 3 to 30 and 37 to 48 form a well-defined molecular core with two antiparallel ?-sheets composed of residues 14 to 16 and 20 to 22, and 27 to 31 and 36 to 40, and three reverse turns at residues 8 to 11 (type II), 17 to 20 (type II?) and 23 to 26 (type II). The average root-mean-square deviation of the individual NMR conformers relative to their mean co-ordinates is 0.38 Å for the backbone atoms and 0.77 Å for all heavy atoms of these residues. Increased structural disorder was found for the N-terminal dipeptide segment, the loop at residues 31 to 36, and the C-terminal tripeptide segment. The solution structure of hirudin(1–51) has the same molecular architecture as the corresponding polypeptide segment in natural hirudin and recombinant desulfatohirudin. It is also closely similar to the crystal structure of the N-terminal 51-residue segment of hirudin in a hirudin-thrombin complex, with root-mean-square deviations of the crystal structure relative to the mean solution structure of 0.61 Å for the backbone atoms and 0.91 Å for all heavy atoms of residues 3 to 30 and 37 to 48. Further coincidence is found for the loop formed by residues 31 to 36, which shows increased structural disorder in all available solution structures of hirudin, and of which residues 32 to 35 are not observable in the electron density map of the thrombin complex. Significant local structural differences between hirudin(1–51) in solution and hirudin in the crystalline thrombin complex were identified mainly for the N-terminal tripeptide segment and residues 17 to 21. These are further analyzed in an accompanying paper.

T. Szyperski; P. Güntert; S.R. Stone; K. Wüthrich

1992-01-01T23:59:59.000Z

183

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

E-Print Network (OSTI)

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.

Jurado, Beatriz

2014-01-01T23:59:59.000Z

184

Investigations of neutron characteristics for salt blanket models; integral fission cross section measurements of neptunium, plutonium, americium and curium isotopes  

SciTech Connect

Neutron characteristics of salt blanket micromodels containing eutectic mixtures of sodium, zirconium and uranium sulphides were measured on FKBN-2M, BIGR and MAKET installations. The effective fission cross sections of neptunium, plutonium, americium and curium isotopes were measured on the neutron spectra formed by micromodels. KEYWORDS: transmutation, minor actinides, fluoride salts, micromodel, critical assembly, neutron spectrum, multiplication coefficient, fission, effective cross section, nuclear track detector, nuclear data library

Novoselov, G. F.; Gavrilov, V. V.; Kuvshinov, M. (Mikhail); Bogdanov, V. M. (Vladimir Mikha?lovich); Maslov, Georgi? Vladimirovich,; Vyachin, V. (Vladimir); Mashnik, S. G. (Stepan G.); Gorelov, V. I. (Vladimir Ivanovich); Fomushkin, E. F.

2001-01-01T23:59:59.000Z

185

Singlet exciton fission in solution  

E-Print Network (OSTI)

is more pronounced for the excimer than in the crystal, as the crystal geometry (at the origin of Fig. 6b) gives a smaller energetic stabilisation than we observe in solution. Though slip- stacked geometries are implicated in J-type coupling between... fission and fusion in a covalently linked tetracene dimer. Chemical Physics Letters 421, 518–522 (2006). 39. Müller, A. M., Avlasevich, Y. S., Schoeller, W. W., Müllen, K. & Bardeen, C. J. Exciton fission and fusion in bis(tetracene) molecules...

Walker, Brian J.; Musser, Andrew J.; Beljonne, David; Friend, Richard H.

2013-11-17T23:59:59.000Z

186

Multiple-Coincidence Interrogation of Fissionables  

SciTech Connect

The multiple coincidence technique uses 14.1 MeV neutrons to produce (n, multiple-?) coincidences to detect fissile and fissionable materials. Measurements of n-?-? coincidences with targets of depleted uranium (DU), W, and Pb, show that the counting rate for the DU is substantially above that for the non-fissionables. Also, the data involving prompt neutrons and delayed gammas in the DU time spectra provide a signature for fissionables that is distinct from that of non-fissionables.

J.P. Hurley, R.P. Keegan, J.R. Tinsley, R. Trainham

2009-05-01T23:59:59.000Z

187

Nuclear | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Nuclear Nuclear Nuclear Radioisotope Power Systems, a strong partnership between the Energy Department's Office of Nuclear Energy and NASA, has been providing the energy for deep space exploration. Nuclear power is the use of sustained nuclear fission to generate heat and electricity. Nuclear power plants provide about 6 percent of the world's energy and 13-14 percent of the world's electricity. Featured Five Years of Building the Next Generation of Reactors Simulated three-dimensional fission power distribution of a single 17x17 rod PWR fuel assembly. | Photo courtesy of the Consortium for Advanced Simulation of Light Water Reactors (CASL). A two-year update on the Consortium for Advanced Simulation of Light Water Reactors and the progress being made in overcoming barriers to national

188

Uncertainty and sensitivity analysis of fission gas behavior in engineering-scale fuel modeling  

SciTech Connect

The role of uncertainties in fission gas behavior calculations as part of engineering-scale nuclear fuel modeling is investigated using the BISON fuel performance code and a recently implemented physics-based model for the coupled fission gas release and swelling. Through the integration of BISON with the DAKOTA software, a sensitivity analysis of the results to selected model parameters is carried out based on UO2 single-pellet simulations covering different power regimes. The parameters are varied within ranges representative of the relative uncertainties and consistent with the information from the open literature. The study leads to an initial quantitative assessment of the uncertainty in fission gas behavior modeling with the parameter characterization presently available. Also, the relative importance of the single parameters is evaluated. Moreover, a sensitivity analysis is carried out based on simulations of a fuel rod irradiation experiment, pointing out a significant impact of the considered uncertainties on the calculated fission gas release and cladding diametral strain. The results of the study indicate that the commonly accepted deviation between calculated and measured fission gas release by a factor of 2 approximately corresponds to the inherent modeling uncertainty at high fission gas release. Nevertheless, higher deviations may be expected for values around 10% and lower. Implications are discussed in terms of directions of research for the improved modeling of fission gas behavior for engineering purposes.

G. Pastore; L.P. Swiler; J.D. Hales; S.R. Novascone; D.M. Perez; B.W. Spencer; L. Luzzi; P. Van Uffelen; R.L. Williamson

2014-10-01T23:59:59.000Z

189

Analysis of linear energy transfers and quality factors of charged particles produced by spontaneous fission neutrons from 252Cf and 244Pu in the human body  

Science Journals Connector (OSTI)

......determining the energy of charged...emitted from neutron-induced nuclear reactions...of neutron spectra on D T and...spontaneous fission of 252Cf...Watt B. E. Energy spectrum of neutrons from thermal fission of 235U...irradiated by high energy hadrons......

Akira Endo; Tatsuhiko Sato

2013-04-01T23:59:59.000Z

190

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

E-Print Network (OSTI)

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

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

2014-03-01T23:59:59.000Z

191

Fission-barrier parameters of the compound nuclei /sup 245/Cm, /sup 247/Cm, and /sup 249/Cm  

SciTech Connect

The cross section for fission of /sup 248/Cm by neutrons has been measured in the energy interval 0.3< or =E/sub n/< or =5.5 MeV. The measurements were made by the time-of-flight method with use of an underground nuclear explosion as a pulsed neutron source. From the experimental data for the compound nuclei /sup 245/Cm, /sup 247/Cm, and /sup 249/Cm we have evaluated the following characteristics of the fission probability: the inner barrier height E/sup A//sub f/, the curvature parameter h..omega../sub A/ and the ratio of the average neutron and fission widths. Some features of the fission probability curves obtained are discussed, and also the question of the applicability of the systematics for prediction of fission characteristics of heavy nuclei with neutron number N>152.

Fomushkin, E.F.; Novoselov, G.F.; Vinogradov, Y.I.; Gavrilov, V.V.

1982-09-01T23:59:59.000Z

192

Prompt Gamma Emission in Resonance Neutron Induced Fission of 239Pu  

Science Journals Connector (OSTI)

The scientific interest in the resonance neutron induced capture and fission reactions on 239Pu is continuously rising during the last decade. From a practical point of view, this is because more precise data on capture and fission cross sections, fission fragment mass and kinetic energy distributions, variation of prompt fission neutron and gamma yields in the resonance neutron region, are needed for the modelling of new generation nuclear power plants and for nuclear spent fuel and waste transmutation. From a heuristic and fundamental point of view, such a research improves our knowledge and understanding of the fission phenomena itself. To achieve these goals more powerful neutron sources and more precise fission product detectors have to be used. At the Joint Institute for Nuclear Research (JINR) Frank Laboratory of Neutron Physics (FLNP), where already half a century the thermal and resonance neutron induced nuclear reactions are studied, a new electron accelerator driven white spectrum pulsed neutron source IREN has been built and successfully tested. The improved characteristics of this facility, in comparison with those of the former pulse neutron fast reactor IBR-30, will allow measuring some of the neutron-nuclear reaction data with better precision and accuracy. A new experimental setup for detecting gamma rays (and neutrons) has been designed and is under construction. It will consist of 2 rings (arrays) of 12 NaI(Tl) detectors each (or 1 array of 24 detectors) with variable ring diameter and distance between both rings. Such a setup will make possible not only to measure the multiplicity, energy and angular anisotropy of prompt fission gammas, but also to separate the contribution of prompt fission neutrons by their longer time-of-flight from the fissile target to the detectors. The signals from all the 24 detectors will be recorded simultaneously in digitized form and will be stored on the hard disk of the personal computer for further off-line analysis. The measurement of the prompt gamma-ray emission from 239Pu resonance neutron induced fission is one of the most probable candidates for the first experiments to be performed at IREN using the newly designed gamma-ray detector.

I. Ruskov; Yu.N. Kopatch; Ts. Panteleev; V.R. Skoy; V.N. Shvetsov; E. Dermendjiev; N. Janeva; L.B. Pikelner; Yu.V. Grigoriev; Zh.V. Mezentseva; I. Ivanov

2012-01-01T23:59:59.000Z

193

Measuring the /sup 247/Cm fission cross section for neutron in the range 0. 02-3. 0 MeV  

SciTech Connect

The authors measured the energy dependence of the cross section for curium 247 fission caused by neutrons in the energy range 0.02-3.0 MeV using the transit time method and a nuclear explosion as an impulse neutron source. A polycarbonate film was used as a fission fragment detector. Tracks resulting from Curium 247 fission fragments were grouped on the basis of neutron energy into 24 intervals ranging from 0.02 to 3.16 MeV. The tracks of fission fragments from the uranium 235 reference isotope were similarly grouped. Results are graphed and tabulated.

Fomushkin, E.F.; Novoselov, G.F.; Vinogradov, Yu.I.; Gavrilov, V.V.; Zherebtsov, V.A.

1987-10-01T23:59:59.000Z

194

A,B,C`s of nuclear science  

SciTech Connect

This introductory level presentation contains information on nuclear structure, radioactivity, alpha decay, beta decay, gamma decay, half-life, nuclear reactions, fusion, fission, cosmic rays, and radiation protection. Nine experiments with procedures and test questions are included.

Noto, V.A. [Mandeville High School, LA (United States); Norman, E.B.; Chan, Yuen-Dat; Dairiki, J.; Matis, H.S.; McMahan, M.A.; Otto, R. [Lawrence Berkeley Lab., CA (United States)

1995-08-07T23:59:59.000Z

195

Realistic fission models, new beta-decay half-lives and the r-process in neutron star mergers  

SciTech Connect

Almost half of heavy nuclei beyond iron are considered to be produced by rapid neutron capture process (r-process). This process occurs in the neutron-rich environment such as core-collapse supernovae or neutron star mergers, but the main production site is still unknown. In the r-process of neutron star mergers, nuclear fission reactions play an important role. Also beta-decay half-lives of magic nuclei are crucial for the r-process. We have carried out r-process nucleosynthesis calculations based upon new theoretical estimates of fission fragment distributions and new beta-decay half-lives for N=82 nuclei measured at RIBF-RIKEN. We investigate the effect of nuclear fission on abundance patterns in the matter ejected from neutron star mergers with two different fission fragment mass distributions. We also discuss how the new experimental beta-decay half-lives affect the r-process.

Shibagaki, S.; Kajino, T. [Department of Astronomy, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan and National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Chiba, S. [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo, 152-8850 (Japan); Lorusso, G.; Nishimura, S. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Mathews, G. J. [Center for Astrophysics, Department of Physics, University of Notre Dame, IN 46556 (United States)

2014-05-02T23:59:59.000Z

196

Transmutation of radioactive nuclear waste — present status and requirement for the problem-oriented nuclear data base  

Science Journals Connector (OSTI)

Transmutation of long-lived actinides and fission products becomes an important issue of the overall nuclear fuel cycle assessment, both for existing and future reactor systems. Reliable nuclear data are required...

Yu. A. Korovin; V. V. Artisyuk; A. V. Ignatyuk; G. B. Pilnov; A. Yu. Stankovsky…

2007-02-01T23:59:59.000Z

197

Nuclear Science Day live webinar (National Nuclear Science Week) - Argonne  

NLE Websites -- All DOE Office Websites (Extended Search)

Nuclear Science Day live webinar Nuclear Science Day live webinar Search Go Home Postdocs Students Student Outreach Resources for Schools U.S.-based International (English) International (Other) Events IGED 2013 Science Careers in Search of Women Girls, choose a career in Nuclear Science and Technology! Argonne Nuclear Engineers tell why they chose a Nuclear Career Resources Contact Us Recent Events Science Careers in Search of Women, Apr. 18, 2013 Junior Girl Scout Workshop 'Atomic Fission Fun with the American Nuclear Society', Jan. 26, 2013 Getting to know nuclear energy: the past, the present & the future - free public lecture (Nov. 15, 2012, Argonne National Laboratory) On January 26, 2013, Argonne staff members participated in the Junior Girl Scout Workshop 'Atomic Fission Fun with the American Nuclear Society'

198

The History of Nuclear Energy | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

History of Nuclear Energy History of Nuclear Energy The History of Nuclear Energy Although they are tiny, atoms have a large amount of energy holding their nuclei together. Certain isotopes of some elements can be split and will release part of their energy as heat. This splitting is called fission. The heat released in fission can be used to help generate electricity in powerplants. Uranium-235 (U-235) is one of the isotopes that fissions easily. During fission, U-235 atoms absorb loose neutrons. This causes U-235 to become unstable and split into two light atoms called fission products. The combined mass of the fission products is less than that of the original U-235. The reduction occurs because some of the matter changes into energy. The energy is released as heat. Two or three neutrons

199

Proton-induced fission of actinides at energies 26.5 and 62.9 MeV--Theoretical interpretation  

SciTech Connect

Fission properties of proton-induced fission on {sup 232}Th, {sup 237}Np, {sup 238}U, {sup 239}Pu and {sup 241}Am 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 sensitivity of the calculations to the input parameters of the code and possible improvements are discussed.

Demetriou, P. [Institute of Nuclear Physics, NCSR 'Demokritos', 15310 Athens (Greece); Keutgen, Th.; Prieels, R.; El Masri, Y. [FNRS and Institut de Physique Nucleaire, Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium)

2011-10-28T23:59:59.000Z

200

PHYSICAL REVIEW C 87, 014617 (2013) Monte Carlo Hauser-Feshbach predictions of prompt fission rays  

E-Print Network (OSTI)

Nuclear Theory Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA (Received 14 for the evaporation of the excited fission fragments. Remaining free model parameters, such as excitation energy, multiplicity distribution, average multiplicity and energy, and multiplicity distribution, are calculated

Danon, Yaron

Note: This page contains sample records for the topic "nuclear fission chain" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

A dynamical treatment of isobaric widths in fission : An example of frozen quantal fluctuations  

E-Print Network (OSTI)

in the case of low energy nuclear fission since the excitation energies involved at scission are only to heavy ion reactions is discussed. Tome 41 No 3 ler FEVRIER 1980 LE JOURNAL DE PHYSIQUE - LETTRES has been recently underlined in heavy ion reactions [1], [2], [3], [4]. Experimentally it appears [1

Boyer, Edmond

202

Abolishing the taboo: President Eisenhower and the permissible use of nuclear weapons for national security.  

E-Print Network (OSTI)

??As president, Dwight Eisenhower believed that nuclear weapons, both fission and fusion, were permissible and desirable assets to help protect U.S. national security against the… (more)

Jones, Brian Madison

2008-01-01T23:59:59.000Z

203

Delayed neutron measurements of 232Th neutron-induced fission  

Science Journals Connector (OSTI)

Abstract Delayed neutrons (DN) play an important role in nuclear reactor physics. Innovative critical reactor studies bring to light the need of new DN yields data. For the thorium fuel cycle DN data for 232Th is needed. In the literature, significant discrepancies were observed for energies below 4 MeV and data are dispersed around 14 MeV. Therefore DN absolute yields from 232Th fission have been determined at the PTB Ion Accelerator Facility in Braunschweig. A consistent set of data has been measured for incident neutrons with energies of 2, 3, 4, 6, 7, 10 and 16 MeV.

X. Ledoux; D. Doré; M. Mosconi; R. Nolte; S. Roettger; S. Varet

2015-01-01T23:59:59.000Z

204

Highly accurate measurements of the spontaneous fission half-life of 240,242Pu  

Science Journals Connector (OSTI)

Fast spectrum neutron-induced fission cross-section data for transuranic isotopes are of special demand from the nuclear data community. In particular highly accurate data are needed for the new generation IV nuclear applications. The aim is to obtain precise neutron-induced fission cross sections for 240Pu and 242Pu. To do so, accurate data on spontaneous fission half-lives must be available. Also, minimizing uncertainties in the detector efficiency is a key point. We studied both isotopes by means of a twin Frisch-grid ionization chamber with the goal of improving the present data on the neutron-induced fission cross section. For the two plutonium isotopes the high ?-particle decay rates pose a particular problem to experiments due to piling-up events in the counting gas. Argon methane and methane were employed as counting gases, the latter showed considerable improvement in signal generation due to its higher drift velocity. The detection efficiency for both samples was determined, and improved spontaneous fission half-lives were obtained with very low statistical uncertainty (0.13% for 240Pu and 0.04% for 242Pu): for 240Pu, T1/2,SF=1.165×1011 yr (1.1%), and for 242Pu, T1/2,SF=6.74×1010 yr (1.3%). Systematic uncertainties are due to sample mass (0.4% for 240Pu and 0.9% for 242Pu) and efficiency (1%).

P. Salvador-Castiñeira; T. Bry?; R. Eykens; F.-J. Hambsch; A. Moens; S. Oberstedt; G. Sibbens; D. Vanleeuw; M. Vidali; C. Pretel

2013-12-18T23:59:59.000Z

205

NUCLEAR POWER AND RESEARCH REACTORS 1939 1942 1943 1944  

E-Print Network (OSTI)

#12;#12;11 #12;2 NUCLEAR POWER AND RESEARCH REACTORS 1939 1942 1943 1944 Nuclear fission discovered Oak Ridge selected as site for World War II Manhattan Project First sustained and controlled nuclear 430 nuclear power reactors are operating in the world, and 103 nuclear power plants produce 20

Pennycook, Steve

206

AFC-1 Fuel Rodlet Fission Power Deposition Validation in ATR  

SciTech Connect

One of the viable options of long-term geological disposal of the nuclear power reactors generated spent fuel is to extract plutonium, the minor actinides (MA) and potentially long-lived fission products from the spent fuel and transmute them into short-lived or stable radionuclides in an appropriate reactor for the reduction of the radiological toxicity of the nuclear waste stream. An important component of that technology will be a non-fertile / low-fertile actinide transmutation fuel form containing the plutonium, neptunium, americium (and possibly curium) isotopes to be transmuted. Such advanced fuel forms, especially ones enriched in the long-life minor actinide (LLMA) elements (i.e., Np, Am, Cm), have minimal irradiation performance data available from which to establish a transmutation fuel form design. Recognizing these needs, an Advanced Fuel Cycle test series-1 (AFC-1) irradiation test on a variety of candidate fuel forms is now being conducted in Advanced Test Reactor (ATR) at the Idaho National Laboratory (INL). The first advanced fuel experiment (AFC-1) has been finalized and the test assembly analyzed for insertion and irradiation in ATR. The ATR core consists of a serpentine and rotationally symmetric fuel assembly about the z-axis of the core center. The plan view of the ATR core configuration is shown in Fig. 5, in Ref. 1. A cadmium filter with a 0.178 cm (0.045") thickness and 121.5 cm (48") in length, is currently used in the actinide-fuel capsule design for the East Flux Trap (EFT) position in ATR, to depress the linear heat generation rate (LHGR) lower than the project’s 330 W/cm limit for the experimental fuel rodlets. The LHGR is proportional to the fission power deposited in the fuel rodlets from the neutron fissions. The fraction of the fission power generated from the neutron fission reactions deposited in the fuel rodlet is an important parameter for test assembly thermal analysis, which will be validated in this summary.

G. S. Chang; M. A. Lillo; D. J. Utterbeck

2008-11-01T23:59:59.000Z

207

Development of position-sensitive time-of-flight spectrometer for fission fragment research  

E-Print Network (OSTI)

A position-sensitive, high-resolution time-of-flight detector for fission fragments has been developed. The SPectrometer for Ion DEterminiation in fission Research (SPIDER) is a $2E-2v$ spectrometer designed to measure the mass of light fission fragments to a single mass unit. The time pick-off detector pairs to be used in SPIDER have been tested with $\\alpha$-particles from $^{229}$Th and its decay chain and $\\alpha$-particles and spontaneous fission fragments from $^{252}$Cf. Each detector module is comprised of a thin electron conversion foil, electrostatic mirror, microchannel plates, and delay-line anodes. Particle trajectories on the order of 700 mm are determined accurately to within 0.7 mm. Flight times on the order of 70 ns were measured with 200 ps resolution FWHM. Computed particle velocities are accurate to within 0.06 mm/ns corresponding to precision of 0.5%. An ionization chamber capable of 400 keV energy resolution coupled with the velocity measurements described here will pave the way for modestly efficient measurements of light fission fragments with unit mass resolution.

C. W. Arnold; F. Tovesson; K. Meierbachtol; T. Bredeweg; M. Jandel; H. J. Jorgenson; A. Laptev; G. Rusev; D. W. Shields; M. White; R. E. Blakeley; D. M. Mader; A. A. Hecht

2014-03-06T23:59:59.000Z

208

Fission dynamics at low excitation energy  

Science Journals Connector (OSTI)

The mass asymmetry in the fission of U236 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.

Y. Aritomo; S. Chiba; F. Ivanyuk

2014-11-18T23:59:59.000Z

209

Event-by-Event Fission with FREYA  

SciTech Connect

The recently developed code FREYA (Fission Reaction Event Yield Algorithm) generates large samples of complete fission events, consisting of two receding product nuclei as well as a number of neutrons and photons, all with complete kinematic information. Thus it is possible to calculate arbitrary correlation observables whose behavior may provide unique insight into the fission process. The presentation first discusses the present status of FREYA, which has now been extended up to energies where pre-equilibrium emission becomes significant and one or more neutrons may be emitted prior to fission. Concentrating on {sup 239}Pu(n,f), we discuss the neutron multiplicity correlations, the dependence of the neutron energy spectrum on the neutron multiplicity, and the relationship between the fragment kinetic energy and the number of neutrons and their energies. We also briefly suggest novel fission observables that could be measured with modern detectors.

Randrup, J; Vogt, R

2010-11-09T23:59:59.000Z

210

Fission-energy release for 16 fissioning nuclides. Final report  

SciTech Connect

Results are presented of a least-squares evaluation of the components of energy release per fission in /sup 232/Th, /sup 233/U, /sup 235/U, /sup 238/U, /sup 239/Pu, and /sup 241/Pu. For completeness, older (1978) results based on systematics are presented for these and ten other isotopes of interest. There have been recent indications that the delayed energy components may be somewhat higher than those used previously, but the LSQ results do not seem to change significantly when modest (approx. 1 MeV) increases in the total delayed energy are included in the inputs. Additional measurements of most of the energy components are still needed to resolve remaining discrepancies.

Sher, R.

1981-03-01T23:59:59.000Z

211

Advances in Nuclear Engineering  

Science Journals Connector (OSTI)

... door, closed for fifteen years, to scientific and technical information about fission and nuclear reactors. In spite of the 1,000 papers published then, there was an enormous amount ... Engineering and Science Conference held in Philadelphia, March 1957, and comprise 130 papers on reactors, fuel and a few other matters, almost all the papers being of American origin ...

T. E. ALLIBONE

1958-07-26T23:59:59.000Z

212

In the OSTI Collections: Fission Theory | OSTI, US Dept of Energy, Office  

Office of Scientific and Technical Information (OSTI)

Fission Theory Fission Theory How do atoms split Interest in the details Macroscopic-microscopic approaches Microscopic approaches Improved theory and design References Additional References Research Organizations Reports available from OSTI's Information Bridge How do atoms split? The main influences on the splitting of atoms were understood in at least a rough way almost as soon as nuclear fission was discovered in 1938. An atom's nucleus is composed of two kinds of nucleons: protons, which all have equal amounts of positive electric charge and thus repel each other, and neutrons, which have no net electric charge and are thus not affected electrically by the protons or each other. If internal electrostatic forces were the only ones that influenced nucleons' motions, the protons

213

Diffusion of fission products and radiation damage in SiC  

Science Journals Connector (OSTI)

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

Johan B Malherbe

2013-01-01T23:59:59.000Z

214

Nuclear Criticality Safety | More Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Criticality Safety Criticality Safety SHARE Criticality Safety Nuclear Criticality Safety ORNL is the lead national laboratory responsible for supporting the National Nuclear Security Administration (NNSA) in managing the US Nuclear Criticality Safety Program. NCSP is chartered to maintain the technical infrastructure (integral experiments, computational tools, training, data, etc.) needed to support safe, efficient fissionable material operations. ORNL has extensive expertise in the area of nuclear criticality safety (NCS) based upon years of experience in the following areas: Operations Support: providing fissionable material operations support for enrichment, fabrication, production, and research; Critical Experiments: performing experiments at the Y-12 Critical Experiment Facility;

215

Reactor power history from fission product signatures  

E-Print Network (OSTI)

The purpose of this research was to identify fission product signatures that could be used to uniquely identify a specific spent fuel assembly in order to improve international safeguards. This capability would help prevent and deter potential...

Sweeney, David J.

2009-05-15T23:59:59.000Z

216

Swelling-resistant nuclear fuel  

DOE Patents (OSTI)

A nuclear fuel according to one embodiment includes an assembly of nuclear fuel particles; and continuous open channels defined between at least some of the nuclear fuel particles, wherein the channels are characterized as allowing fission gasses produced in an interior of the assembly to escape from the interior of the assembly to an exterior thereof without causing significant swelling of the assembly. Additional embodiments, including methods, are also presented.

Arsenlis, Athanasios (Hayward, CA); Satcher, Jr., Joe (Patterson, CA); Kucheyev, Sergei O. (Oakland, CA)

2011-12-27T23:59:59.000Z

217

Emission of Prompt Neutrons from Fission  

Science Journals Connector (OSTI)

An analysis of the total energies of the fragment pairs from fission is used with the mass equation of fission to estimate the distributions in the excitation energy of the fragments from spontaneous and neutron-induced fission of several nuclides. These excitations are used with simple neutron boil-off considerations to calculate the probabilities of emission of 0, 1, 2, 3... prompt neutrons. The calculated results are in good agreement with recent measurements.The same excitation energy distributions and neutron boil-off considerations are used with an assumption of an isotropic angular relation between the fragments and the emitted neutrons to calculate the energy spectrum of neutrons from thermal and 3-Mev neutron-induced fission of U235. For thermal-neutron fission, the calculated spectrum is in fair agreement with recent measurements. The calculations indicate little change in the spectrum for 3-Mev fission. The average energy of the prompt gamma rays is 3.8 Mev from this analysis.

R. B. Leachman

1956-02-01T23:59:59.000Z

218

Theoretical descriptions of neutron emission in fission  

SciTech Connect

Brief descriptions are given of the observables in neutron emission in fission together with early theoretical representations of two of these observables, namely, the prompt fission neutron spectrum N(E) and the average prompt neutron multiplicity {bar {nu}}{sub p}. This is followed by summaries, together with examples, of modern approaches to the calculation of these two quantities. Here, emphasis is placed upon the predictability and accuracy of the new approaches. In particular, the dependencies of N(E) and {bar {nu}}{sub p} upon the fissioning nucleus and its excitation energy are discussed. Then, recent work in multiple-chance fission and other recent work involving new measurements are presented and discussed. Following this, some properties of fission fragments are mentioned that must be better known and better understood in order to calculate N(E) and {bar {nu}}{sub p} with higher accuracy than is currently possible. In conclusion, some measurements are recommended for the purpose of benchmarking simultaneous calculations of neutron emission and gamma emission in fission. 32 refs., 26 figs.

Madland, D.G.

1990-01-01T23:59:59.000Z

219

Identification of nuclear weapons  

DOE Patents (OSTI)

A method and apparatus for non-invasively indentifying different types of nuclear weapons is disclosed. A neutron generator is placed against the weapon to generate a stream of neutrons causing fissioning within the weapon. A first detects the generation of the neutrons and produces a signal indicative thereof. A second particle detector located on the opposite side of the weapon detects the fission particles and produces signals indicative thereof. The signals are converted into a detected pattern and a computer compares the detected pattern with known patterns of weapons and indicates which known weapon has a substantially similar pattern. Either a time distribution pattern or noise analysis pattern, or both, is used. Gamma-neutron discrimination and a third particle detector for fission particles adjacent the second particle detector are preferably used. The neutrons are generated by either a decay neutron source or a pulled neutron particle accelerator.

Mihalczo, J.T.; King, W.T.

1987-04-10T23:59:59.000Z

220

Increasing the Work-Safety in Nuclear Power Plants through the Use of Preventive Maintenance Policies  

Science Journals Connector (OSTI)

Nuclear power is being used at an increasing rate as a substitute for scarce and expensive classical energy sources. Controlled nuclear fission generates energy but, at the same time, produces radioactive subs...

Dr. U. Pachow; Prof. Dr. H. Gehring; H. J. Rokohl

1982-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "nuclear fission chain" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

E-Print Network 3.0 - asymmetric nucleon-induced fission Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

POLONICA B No 4 BIMODAL FISSION Summary: modes allows to describe observed asymmetric fis- sion of 256 Fm, as well as bimodal fission of 258 Fm... fission, respectively....

222

E-Print Network 3.0 - asymmetrical fission type Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

POLONICA B No 4 BIMODAL FISSION Summary: modes allows to describe observed asymmetric fis- sion of 256 Fm, as well as bimodal fission of 258 Fm... fission, respectively....

223

Development of position-sensitive time-of-flight spectrometer for fission fragment research  

E-Print Network (OSTI)

A position-sensitive, high-resolution time-of-flight detector for fission fragments has been developed. The SPectrometer for Ion DEterminiation in fission Research (SPIDER) is a $2E-2v$ spectrometer designed to measure the mass of light fission fragments to a single mass unit. The time pick-off detector pairs to be used in SPIDER have been tested with $\\alpha$-particles from $^{229}$Th and its decay chain and $\\alpha$-particles and spontaneous fission fragments from $^{252}$Cf. Each detector module is comprised of a thin electron conversion foil, electrostatic mirror, microchannel plates, and delay-line anodes. Particle trajectories on the order of 700 mm are determined accurately to within 0.7 mm. Flight times on the order of 70 ns were measured with 200 ps resolution FWHM. Computed particle velocities are accurate to within 0.06 mm/ns corresponding to precision of 0.5%. An ionization chamber capable of 400 keV energy resolution coupled with the velocity measurements described here will pave the way for mode...

Arnold, C W; Meierbachtol, K; Bredeweg, T; Jandel, M; Jorgenson, H J; Laptev, A; Rusev, G; Shields, D W; White, M; Blakeley, R E; Mader, D M; Hecht, A A

2014-01-01T23:59:59.000Z

224

Fission product retention in newly discovered organic-rich natural fission reactors at Oklo and Bangombe, Gabon  

SciTech Connect

The discovery of naturally occurring fission reactors in the rock strata of the Paleoproterozoic Francevillian Basin in the Republic of Gabon in equatorial West Africa led to several programs to define migration and/or retention of uranium and fissiogenic isotopes from/in the natural reactor zones. Although much understanding has been gained, new insight is needed regarding the chemical and physical parameters that control movement and retention of fission products over almost two billion years from/in the natural reactors. Seventeen known natural fission reactors sustained criticality for 0.1 to 1 million years in hydrothermally altered sedimentary rocks 1968 +/- 50 million years ago. These natural nuclear reactors attained criticality because of high concentrations of uranium in small pockets in uranium ores, the lack of neutron poisons, and because at the time they reached criticality, the abundance of [sup 235]U was five times greater than it is today. Water acted as a moderator, and temperature in the natural reactors was between 160 and 360[degrees]C. Both the uranium-rich pockets and the uranium ore bodies in which these pockets are located were formed when aqueous solutions moving through highly fractured zones in the Francevillian sedimentary rocks met organic-rich sediments. This resulted in the reduction of U(VI) in the dissolved uranyl ions to U(IV), causing the precipitation of pitchblende and uraninite. It has been proposed that between 2.2 and 1.9 billion years ago, the earth's atmosphere experienced a remarkable temporary rise in O[sub 2] content; this event may account for the uranium-bearing, oxidizing aqueous solutions in the Francevillian rocks.

Nagy, B.; Rigali, M.J. (Univ. of Arizona, Tucson (United States))

1993-01-01T23:59:59.000Z

225

The vacuum system for the Munich fission fragment accelerator  

Science Journals Connector (OSTI)

The Munich Accelerator for Fission Fragments (MAFF) is a radioactive ion beam facility which will be installed at the new research reactor FRM-II. This new reactor became critical in Spring 2004. The heart of MAFF, the target-ion source unit will be placed in the through-going beam tube of the FRM-II. This beam tube has been installed, tested and filled with helium in 2001. The cogent authorization procedures and safety levels developed for nuclear power plants are applied for this research reactor also. Therefore, MAFF also has to obey these very strict rules, because the typical 1 g load of 235U in the MAFF source creates a fission product activity of several 1014 Bq after one reactor cycle of 52 days. All vacuum components must withstand a pressure of 6×105 Pa in addition to their UHV acceptability. Even dynamic gaskets must be strictly metallic, because organic compounds would not withstand the radioactive irradiation during the design lifetime of 30 years. Only dry vacuum pumps are suitable: refrigerator cryopumps for the high-vacuum part and five stages of roots pumps for roughing and regeneration.

P. Maier-Komor; T. Faestermann; R. Krücken; F. Nebel; S. Winkler; M. Groß; D. Habs; O. Kester; J. Szerypo; P.G. Thirolf

2006-01-01T23:59:59.000Z

226

Fission Power: An Evolutionary Strategy  

Science Journals Connector (OSTI)

...for Use in Nuclear Energy Systems Studies (Hanford Engineering Develop-ment Laboratory, Hanford, Wash., October 1977). One change that...economy growing through 450 GWe in the year 2000. It includes the 0.34 million tons of by-product...

Harold A. Feiveson; Frank von Hippel; Robert H. Williams

1979-01-26T23:59:59.000Z

227

Manhattan Project: Fission Comes to America, 1939  

Office of Scientific and Technical Information (OSTI)

Excerpt from the comic book "Adventures Inside the Atom." Click on this image or visit the "Library" to view the whole comic book. FISSION COMES TO AMERICA Excerpt from the comic book "Adventures Inside the Atom." Click on this image or visit the "Library" to view the whole comic book. FISSION COMES TO AMERICA (1939) Events > Atomic Discoveries, 1890s-1939 A Miniature Solar System, 1890s-1919 Exploring the Atom, 1919-1932 Atomic Bombardment, 1932-1938 The Discovery of Fission, 1938-1939 Fission Comes to America, 1939 News of the fission experiments of Otto Hahn and Fritz Strassmann, and of the Meitner-Frisch calculations that confirmed them, spread rapidly. Meitner and Frisch communicated their results to Niels Bohr, who was in Copenhagen preparing to depart for the United States via Sweden and England. Bohr confirmed the validity of the findings while sailing to New York City, arriving on January 16, 1939. Ten days later Bohr, accompanied by Enrico Fermi, communicated the latest developments to some European émigré scientists who had preceded him to this country and to members of the American scientific community at the opening session of a conference on theoretical physics in Washington, D.C.

228

Properties of prompt-fission ? rays  

Science Journals Connector (OSTI)

In a Monte Carlo Hauser-Feshbach statistical framework, we describe spectra, average multiplicities, average energy, and multiplicity distributions of the prompt ? rays produced in the thermal neutron-induced fission of U235 and Pu239, and the spontaneous fission of Cf252. Comparisons against recent experimental data show reasonable agreement in all cases investigated, after adjustment of the initial spin distribution in the fission fragments. In particular, when we include in the calculation the Doppler broadening we obtain a qualitatively good description of the measured low-energy spectra, where contributions from collective discrete transitions in specific fragments can be identified. At higher energies, both the calculated neutron and ?-ray spectra are softer than experimental data. The impact of selected model parameters on the prompt neutron and ?-ray spectra is analyzed. Finally, we present the prompt ? spectrum and multiplicity distribution for the neutron-induced fission of U235 for 5.5 MeV neutron incident energy, just below the threshold for second-chance fission.

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

2014-08-26T23:59:59.000Z

229

Large Scale Weather Control Using Nuclear Reactors  

E-Print Network (OSTI)

It is pointed out that controlled release of thermal energy from fission type nuclear reactors can be used to alter weather patterns over significantly large geographical regions. (1) Nuclear heat creates a low pressure region, which can be used to draw moist air from oceans, onto deserts. (2) Creation of low pressure zones over oceans using Nuclear heat can lead to Controlled Cyclone Creation (CCC).(3) Nuclear heat can also be used to melt glaciers and control water flow in rivers.

Moninder Singh Modgil

2002-10-02T23:59:59.000Z

230

Linear chain magnetism  

Science Journals Connector (OSTI)

Linear chain magnetism ... A brief introduction to this concept, which is also called lower dimensional magnetism. ...

Richard L. Carlin

1991-01-01T23:59:59.000Z

231

A proton?driven, intense, subcritical, fission neutron source for radioisotope production  

Science Journals Connector (OSTI)

99mTc the most frequently used radioisotope in nuclear medicine is distributed as 99Mo?99mTc generators. 99 Mo is a fission product of 235U. To replace the aging nuclear reactors used today for this production we propose to use a spallation neutron source with neutron multiplication by fission. A 150 MeV H? cyclotron can produce a 225 kW proton beam with 50% total system energy efficiency. The proton beam would hit a molten lead target surrounded by a water moderator and a graphite reflector producing around 0.96 primary neutron per proton. The primary spallation neutrons moderated would strike secondary targets containing a subcritical amount of 235U. The assembly would show a keff of 0.8 yielding a fivefold neutron multiplication. The thermal neutron flux at the targets location would be 2 1014 n/cm2.s resulting in a fission power of 500 to 750 kW. One such system could supply the world demand in 99 Mo as well as other radioisotopes. Preliminary indications show that the cost would be lower than the cost of a commercial 10 MW isotope production reactor. The cost of operation of disposal of radiowaste and of decommissioning should be significantly lower as well. Finally the non?critical nature of the system would make it more acceptable for the public than a nuclear reactor and should simplify the licensing process.

Yves Jongen

1995-01-01T23:59:59.000Z

232

Magnetic moments of long isotopic chains  

E-Print Network (OSTI)

Dipole magnetic moments of several long isotopic chains are analyzed within the self-consistent Finite Fermi System theory based on the Generalized Energy Density Functional method with exact account for the pairing and quasi-particle continuum. New data for nuclei far from the beta-stability valley are included in the analysis. For a number of semi-magic isotopes of the tin and lead chains a good description of the data is obtained, with accuracy of 0.1 - 0.2 mu_N. A chain of non-magic isotopes of copper is also analyzed in detail. It is found that the systematic analysis of magnetic moments of this long chain yields rich information on the evolution of the nuclear structure of the Cu isotopes. In particular, it may give a signal of deformation for the ground state of some nuclei in the chain.

I. N. Borzov; E. E. Saperstein; S. V. Tolokonnikov; G. Neyens; N. Severijns

2008-04-28T23:59:59.000Z

233

Plasma Mass Filters For Nuclear Waste Reprocessing  

SciTech Connect

Practical disposal of nuclear waste requires high-throughput separation techniques. The most dangerous part of nuclear waste is the fission product, which contains the most active and mobile radioisotopes and produces most of the heat. We suggest that the fission products could be separated as a group from nuclear waste using plasma mass filters. Plasmabased processes are well suited to separating nuclear waste, because mass rather than chemical properties are used for separation. A single plasma stage can replace several stages of chemical separation, producing separate streams of bulk elements, fission products, and actinoids. The plasma mass filters may have lower cost and produce less auxiliary waste than chemical processing plants. Three rotating plasma configurations are considered that act as mass filters: the plasma centrifuge, the Ohkawa filter, and the asymmetric centrifugal trap.

Abraham J. Fetterman and Nathaniel J. Fisch

2011-05-26T23:59:59.000Z

234

Energy partition in low energy fission  

E-Print Network (OSTI)

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 center Woods-Saxon shell model. It is shown that the available intrinsic dissipated energy is not shared proportionally to the masses of the two fission fragments. If the heavy fragment possesses nucleon numbers close to the magic ones, the accumulated intrinsic excitation energy is lower than that of the light fragment.

M. Mirea

2011-02-14T23:59:59.000Z

235

Prompt Fission Neutron Spectrum of Pu241  

Science Journals Connector (OSTI)

The energy distribution of prompt neutrons resulting from the thermal-neutron-induced fission of Pu241 is measured. Fast time-of-flight techniques are employed in the neutron energy range 0.3 to 6.0 Mev. Proton recoils in emulsions are utilized for the measurement of neutron energies from 1.6 to 7.0 Mev. The experimentally determined Pu241 fission neutron spectrum is well represented by the Maxwellian distribution, N(E)?E12e-ET, where E is the neutron energy in Mev, N(E) the number of neutrons per unit energy interval, and T=1.335±0.034 Mev. The measured average Pu241 fission neutron energy is 2.002±0.051 Mev.

A. B. Smith; R. K. Sjoblom; J. H. Roberts

1961-09-15T23:59:59.000Z

236

Spectroscopy of element 115 decay chains  

SciTech Connect

A high-resolution a, X-ray and -ray coincidence spectroscopy experiment was conducted at the GSI Helmholtzzentrum fu r Schwerionenforschung. Thirty correlated a-decay chains were detected following the fusion-evaporation reaction 48Ca + 243Am. The observations are consistent with previous assignments of similar decay chains to originate from element Z = 115. The data includes first candidates of fingerprinting the decay step Mt --> Bh with characteristic X rays. For the first time, precise spectroscopy allows the derivation of excitation schemes of isotopes along the decay chains starting with elements Z > 112. Comprehensive Monte-Carlo simulations accompany the data analysis. Nuclear structure models provide a first level interpretation.

Rudolph, Dirk [Lund University, Sweden; Forsberg, U. [Lund University, Sweden; Golubev, P. [Lund University, Sweden; Sarmiento, L. G. [Lund University, Sweden; Yakushev, A. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Andersson, L.-L. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Di Nitto, A. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Duehllmann, Ch. E. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Gates, J. M. [Lawrence Berkeley National Laboratory (LBNL); Gregorich, K. E. [Lawrence Berkeley National Laboratory (LBNL); Gross, Carl J [ORNL; Hessberger, F. P. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Herzberg, R.-D [University of Liverpool; Khuyagbaatar, J. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Kratz, J. V. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Rykaczewski, Krzysztof Piotr [ORNL; Schaedel, M. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Aberg, S. [Lund University, Sweden; Ackermann, D. [GSI-Hemholtzzentrum fur Schwerionenforschung, Darmstadt, Germany; Block, M. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Brand, H. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Carlsson, B. G. [Lund University, Sweden; Cox, D. [University of Liverpool; Derkx, X. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Eberhardt, K. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Even, J. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Fahlander, C. [Lund University, Sweden; Gerl, J. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Jaeger, E. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Kindler, B. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Krier, J. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Kojouharov, I. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Kurz, N. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Lommel, B. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Mistry, A. [University of Liverpool; Mokry, C. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Nitsche, H. [Lawrence Berkeley National Laboratory (LBNL); Omtvedt, J. P. [Paul Scherrer Institut, Villigen, Switzerland; Papadakis, P. [University of Liverpool; Ragnarsson, I. [Lund University, Sweden; Runke, J. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Schaffner, H. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Schausten, B. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Thoerle-Pospiech, P. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Torres, T. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Traut, T. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Trautmann, N. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Tuerler, A. [Paul Scherrer Institut, Villigen, Switzerland; Ward, A. [University of Liverpool; Ward, D. E. [Lund University, Sweden; Wiehl, N. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany

2013-01-01T23:59:59.000Z

237

Elevated Radioxenon Detected Remotely Following the Fukushima Nuclear Accident  

SciTech Connect

We report on the first measurements of short-lived gaseous fission products detected outside of Japan following the Fukushima nuclear releases, which occurred after a 9.0 magnitude earthquake and tsunami on March 11, 2011.

Bowyer, Ted W.; Biegalski, Steven R.; Cooper, Matthew W.; Eslinger, Paul W.; Haas, Derek A.; Hayes, James C.; Miley, Harry S.; Strom, Daniel J.; Woods, Vincent T.

2011-04-21T23:59:59.000Z

238

Stellarator-Mirror Based Fusion Driven Fission Reactor  

Science Journals Connector (OSTI)

In a sub-critical fast fission reactor the neutron multiplication factor k eff, is less than unity. The coefficient k eff...is the average number of neutrons from a single fission ...

V. E. Moiseenko; K. Noack; O. Ågren

2010-02-01T23:59:59.000Z

239

Uncertainty Quantification on Prompt Fission Neutrons Spectra  

Science Journals Connector (OSTI)

Uncertainties in the evaluated prompt fission neutrons spectra present in ENDF/B-VII.0 are assessed in the framework of the Los Alamos model. The methodology used to quantify the uncertainties on an evaluated spectrum is introduced. We also briefly review the Los Alamos model and single out the parameters that have the largest influence on the calculated results. Using a Kalman filter, experimental data and uncertainties are introduced to constrain model parameters, and construct an evaluated covariance matrix for the prompt neutrons spectrum. Preliminary results are shown in the case of neutron-induced fission of 235U from thermal up to 15 MeV incident energies.

P. Talou; D.G. Madland; T. Kawano

2008-01-01T23:59:59.000Z

240

Fission decay in intermediate heavy ion reactions  

SciTech Connect

Results are presented on cross sections, parallel and perpendicular momentum transfers, charge loss and velocity systematics for fission following reactions of Fe and Nb projectiles at 50--100 MeV/A on targets of Ta, Au, and Th. The results at 100 MeV/A are compared to a detailed multistage deexcitation model. The initial collision is modeled with an intranuclear cascade. The resultant excited target residues then undergo a fast preequilibrium decay stage followed by a statistical decay involving nucleon evaporation and fission. Results from this modeling are in reasonable agreement with experimental data. 14 refs., 11 figs.

Britt, H.C.

1990-10-03T23:59:59.000Z

Note: This page contains sample records for the topic "nuclear fission chain" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Alpha decay from fission isomeric states  

Science Journals Connector (OSTI)

Alpha-decay half-lives from shape isomeric states of some even-even isotopes of U, Pu and Cm nuclei are calculated by using fission theory in the parametrisation of a spheroid intersected with a sphere. The potential barrier was calculated in the framework of the liquid-drop model of Myers and Swiatecki (1967) extended for systems with different charge densities; a phenomenological shell correction was introduced. The WKB computed lifetimes are many orders of magnitude longer than that of the spontaneous fission process, in agreement with experimental results.

D N Poenaru; M Ivascu

1981-01-01T23:59:59.000Z

242

Fission signal detection using helium-4 gas fast neutron scintillation detectors  

SciTech Connect

We demonstrate the unambiguous detection of the fission neutron signal produced in natural uranium during active neutron interrogation using a deuterium-deuterium fusion neutron generator and a high pressure {sup 4}He gas fast neutron scintillation detector. The energy deposition by individual neutrons is quantified, and energy discrimination is used to differentiate the induced fission neutrons from the mono-energetic interrogation neutrons. The detector can discriminate between different incident neutron energies using pulse height discrimination of the slow scintillation component of the elastic scattering interaction between a neutron and the {sup 4}He atom. Energy histograms resulting from this data show the buildup of a detected fission neutron signal at higher energies. The detector is shown here to detect a unique fission neutron signal from a natural uranium sample during active interrogation with a (d, d) neutron generator. This signal path has a direct application to the detection of shielded nuclear material in cargo and air containers. It allows for continuous interrogation and detection while greatly minimizing the potential for false alarms.

Lewis, J. M., E-mail: lewisj@ufl.edu; Kelley, R. P.; Jordan, K. A. [Nuclear Engineering Program, University of Florida, Gainesville, Florida 32611 (United States); Murer, D. [Arktis Radiation Detectors Ltd., 8045 Zurich (Switzerland)

2014-07-07T23:59:59.000Z

243

Half-life for spontaneous fission of /sup 243/Cm  

SciTech Connect

A method is proposed for measuring the half-life for spontaneous fission of curium 243. Isotope separation and purification techniques are described and the isotope ratio of the purified target is given. The efficiency of fission fragment detection for solid state mica detectors was measured with a curium 244 standard. Results for the rate of spontaneous fission are tabulated.

Polynov, V.N.; Druzhinin, A.A.; Korochkin, A.M.; Nikitin, E.A.; Bochkarev, V.A.; Vyachin, V.N.; Lapin, V.G.; Maksimov, M.Yu.

1987-10-01T23:59:59.000Z

244

Study of Neutron-Induced Fission Cross Sections of U, Am, and Cm at n{sub T}OF  

SciTech Connect

Neutron induced fission cross sections of several isotopes have been measured at the CERN n{sub T}OF spallation neutron facility. Between them some measurements involve isotopes ({sup 233}U, {sup 241}Am, {sup 243}Am, {sup 245}Cm) relevant for applications to nuclear technologies. The n{sub T}OF facility delivers neutrons with high instantaneous flux and in a wide energy range, from thermal up to 250 MeV. The experimental apparatus consists of an ionization chamber that discriminates fission fragments and {alpha} particles coming from natural radioactivity of the samples. All the measurements were performed referring to the standard cross section of {sup 235}U.

Milazzo, P. M.; Abbondanno, U.; Belloni, F.; Fujii, K. [INFN, Trieste (Italy); Aerts, G.; Andriamonje, S.; Berthoumieux, E.; Dridi, W.; Ferrant, L.; Gunsing, F.; Pancin, J.; Perrot, L.; Plukis, A.; Stephan, C.; Tassan-Got, L. [CNRS/IN2P3-IPN, Orsay (France); Alvarez, H.; Duran, I.; Paradela, C. [Universidade de Santiago de Compostela (Spain); Alvarez-Velarde, F.; Cano-Ott, D. [CIEMAT, Madrid (Spain)

2010-08-04T23:59:59.000Z

245

Position reconstruction in fission fragment detection using the low pressure MWPC technique for the JLab experiment E02-017  

SciTech Connect

When a lambda hyperon was embedded in a nucleus, it can form a hypernucleus. The lifetime and its mass dependence of stable hypernuclei provide information about the weak decay of lambda hyperon inside nuclear medium. This work will introduce the Jefferson Lab experiment (E02-017) which aims to study the lifetime of the heavy hypernuclei using a specially developed fission fragment detection technique, a multi-wire proportional chamber operated under low gas pressure (LPMWPC). Presented here are the method and performance of the reconstruction of fission position on the target foil, the separation of target materials at different regions and the comparison and verification with the Mote Carlo simulation.

Xi-Yu, Qiu [Lanzhou U.; Tang, Liguang [JLAB; Margaryan, Amur T. [Yerevan; Jin-Zhang, Xu [Lanzhou; Bi-Tao, Hu [Lanzhou; Xi-Meng, Chen [Lanzhou

2014-07-01T23:59:59.000Z

246

Covariances of Prompt Fission Neutron Spectra  

Science Journals Connector (OSTI)

Following the outcomes and the recommendations of the Working Party on Evaluation Cooperation (WPEC) SG-26 the impact of the uncertainties and energy correlations in the prompt neutron fission spectra (PFNS) was studied in several critical benchmarks, both thermal and fast. Two different approaches to calculate the sensitivity of keff with respect to the fission neutron spectra, including the new so-called normalized sensitivity method, were used as a means to check and assure the mathematical correctness of the derived fission spectrum covariance matrices. A new Monte Carlo (MC) method has been proposed and applied to produce the covariance matrices of the PFNS for the neutron induced fission on 235U, 238U and 239Pu nuclei. The MC method was validated by comparison with the matrix derived analytically using the so-called File-30 formalism in ENDF terminology. Several sets of covariance matrices of the PFNS of 235U, 238U and 239Pu nuclei were derived from the uncertainties assigned to the model parameters of the Watt and the recently proposed Kornilov PFNS parameterizations.

I. Kodeli; R. Capote; A. Trkov

2008-01-01T23:59:59.000Z

247

Transfer-induced fission of superheavy nuclei  

SciTech Connect

Possibilities of transfer-induced fission of new isotopes of superheavy nuclei with charge numbers 103-108 are studied for the first time in the reactions {sup 48}Ca+{sup 244,246,248}Cm at energies near the corresponding Coulomb barriers. The predicted cross sections are found to be measurable with the detection of three-body final states.

Adamian, G. G. [Joint Institute for Nuclear Research, RU-141980 Dubna (Russian Federation); Institute of Nuclear Physics, Tashkent, UZ-702132 Uzbekistan (Uzbekistan); Antonenko, N. V.; Zubov, A. S. [Joint Institute for Nuclear Research, RU-141980 Dubna (Russian Federation); Sargsyan, V. V. [Joint Institute for Nuclear Research, RU-141980 Dubna (Russian Federation); Yerevan State University, Yerevan (Armenia); Scheid, W. [Institut fuer Theoretische Physik der Justus-Liebig-Universitaet, D-35392 Giessen (Germany)

2010-07-15T23:59:59.000Z

248

Spontaneous fission properties of Rf104262  

Science Journals Connector (OSTI)

We have measured the mass and kinetic-energy distributions of fragments from the spontaneous fission (SF) of Rf104262. The Rf104262 was produced via the Pu244(22Ne,4n) reaction with a production cross section of ?0.7 nb using 114.4-MeV projectiles. The kinetic energies and times of the coincident fission fragments were measured using our rotating wheel system. From these data the half-life, mass, and kinetic-energy distributions were derived. The total kinetic-energy (TKE) distribution appears to consist of a single component with a most probable pre-neutron-emission TKE of 215±2 MeV. The mass distribution is symmetric with a full width at half maximum of about 22 mass numbers. These results are consistent with trends observed for other trans-berkelium spontaneously fissioning isotopes. We determined the half-life to be 2.1±0.2 s by measuring its spontaneous fission decay. We also attempted to observe the alpha decay of Rf104262 by searching for alpha decay correlated in time with SF from the alpha daughter, 1.2-ms No258. We observed no such decays and have set an upper limit of 0.8% (68% confidence level) on the alpha decay branch of Rf104262. © 1996 The American Physical Society.

M. R. Lane; K. E. Gregorich; D. M. Lee; M. F. Mohar; M. Hsu; C. D. Kacher; B. Kadkhodayan; M. P. Neu; N. J. Stoyer; E. R. Sylwester; J. C. Yang; D. C. Hoffman

1996-06-01T23:59:59.000Z

249

Fission Detection Using the Associated Particle Technique  

SciTech Connect

A beam of tagged 14 MeV neutrons from the deuterium-tritium (DT) reaction is used to induce fission in a target composed of depleted uranium. The generator yield is 107 neutrons/second radiated into a 4? solid angle. Two 4 in.×4 in. NaI detectors are used for gamma-ray detection. The fission process is known to produce multiple gamma-rays and neutrons. Triple coincidences (?-?-?) are measured as a function of neutron flight time up to 90 ns after fission, where the ?-particle arises from the DT reaction. A sudden increase in the triple coincidence rate at the location of the material is used to localize and detect fission in the interrogated target. Comparisons are made with experiment runs where lead, tungsten, and iron were used as target materials. The triple coincidence response profile from depleted uranium is noted to be different to those observed from the other target materials. The response from interrogation targets composed of fissile material is anticipated to be even more unique than that observed from depleted uranium.

R.P. Keegan, J.P. Hurley, J.R. Tinsley, R. Trainham, S.C. Wilde

2008-09-18T23:59:59.000Z

250

Most Viewed Documents for Fission And Nuclear Technologies: September...  

Office of Scientific and Technical Information (OSTI)

PWR and BWR Not Available (1975) 27 Sloshing analysis of viscous liquid storage tanks Uras, R.Z. (1995) 22 Flow-induced vibration of circular cylindrical structures Chen,...

251

April 2013 Most Viewed Documents for Fission And Nuclear Technologies...  

Office of Scientific and Technical Information (OSTI)

W.B.; Allison, G.S. (1979) 89 > Sloshing analysis of viscous liquid storage tanks Uras, R.Z. (1995) 83 > Thermophysical properties of sodium nitrate and sodium...

252

Quasidynamic propagation in diabatic landscapes for low energy nuclear fission  

Science Journals Connector (OSTI)

Successive procedure for evaluating diabatic contributions to the static energy surface is proposed, based on solving collective equation of motion simultaneously with equations for the single-particle occupat...

M. T. Matev; B. Slavov

1991-01-01T23:59:59.000Z

253

Nuclear Fission: Reaction to the Discovery in 1939  

E-Print Network (OSTI)

U-235. As is well known, Glenn Seaborg soon discovered thisinformal and formal. Glenn Seaborg remembered " a seminar in

Hodes, Elizabeth; Tiddens, Adolph; Badash, Lawrence

1985-01-01T23:59:59.000Z

254

Nuclear fission: the interplay of science and technology  

Science Journals Connector (OSTI)

...B. G. 2001 The health hazards of depleted uranium munitions: part 1...B. G. 2002 a The health hazards of depleted uranium munitions: part 2...B. G. 2002 b The health hazards of depleted uranium munitions summary of...

2010-01-01T23:59:59.000Z

255

Most Viewed Documents - Fission and Nuclear Technologies | OSTI...  

Office of Scientific and Technical Information (OSTI)

States) (1997) Environmental Aspects, Objectives and Targets Identification Process R. Green (2002) Flow-induced vibration of circular cylindrical structures Chen, S.S. (1985)...

256

Nuclear reactor fuel structure containing uranium alloy wires embedded in a metallic matrix plate  

SciTech Connect

A nuclear fuel-containing plate structure for a nuclear reactor is described; such structure comprising a pair of malleable metallic non-fissionable matrix plates having confronting surfaces which are pressure bonded together and fully united to form a bonded surface, and elongated malleable wire-like fissionable fuel members separately confined and fully enclosed between the matrix plates along the interface to afford a high fuel density as well as structural integrity and effective retention of fission products. The plates have separate recesses formed in the confronting surfaces for closely receiving the wire-like fissionable fuel members. The wire-like fissionable fuel members are made of a maleable uranium alloy capable of being formed into elongated wire-like members and capable of withstanding pressure bonding. The wire-like fissionable fuel members are completely separated and isolated by fully united portions of the interface.

Travelli, A.

1988-01-19T23:59:59.000Z

257

Neutron induced fission of Pu240,242 from 1 eV to 200 MeV  

Science Journals Connector (OSTI)

The neutron induced fission cross sections of Pu240,242 have been measured as a function of incident neutron energy from 1 eV to 200 MeV. This is part of an effort to reduce experimental uncertainties of nuclear data in support of next generation nuclear reactors and transmutation technology. These two plutonium isotopes are nonfissile, and the available data are limited below reaction threshold. The present data demonstrate the presence of a 2.67 eV resonance in the Pu242 fission cross section, which is missing in the ENDF/B-VII evaluation, and resolve discrepancies in the keV region. The measured cross sections are also compared with statistical model calculations made with the nuclear reaction code GNASH.

F. Tovesson; T. S. Hill; M. Mocko; J. D. Baker; C. A. McGrath

2009-01-29T23:59:59.000Z

258

The ABC's of Nuclear Science  

NLE Websites -- All DOE Office Websites (Extended Search)

Basic Nuclear Science Basic Nuclear Science Cosmic Connection Presentations Experiments Antimatter Make a Nucleus Glossary Safety Credits Praise CPEP Speak With Us Boy Scout Merit Badge Translations Guide to the Nuclear Wall Chart About the Nuclear Wall Chart Privacy and Security Notice Other Interesting Sites Last updated: September 26, 2013 Contact Us The ABC's Of Nuclear Science The ABC's of Nuclear Science is a brief introduction to Nuclear Science. We look at Antimatter, Beta rays, Cosmic connection and much more. Visit here and learn about radioactivity - alpha, beta and gamma decay. Find out the difference between fission and fusion. Learn about the structure of the atomic nucleus. Learn how elements on the earth were produced. Do you know that you are being bombarded constantly by nuclear radiation from the

259

Monte Carlo Modeling of Photon Interrogation Methods for Characterization of Special Nuclear Material  

SciTech Connect

This work illustrates a methodology based on photon interrogation and coincidence counting for determining the characteristics of fissile material. The feasibility of the proposed methods was demonstrated using a Monte Carlo code system to simulate the full statistics of the neutron and photon field generated by the photon interrogation of fissile and non-fissile materials. Time correlation functions between detectors were simulated for photon beam-on and photon beam-off operation. In the latter case, the correlation signal is obtained via delayed neutrons from photofission, which induce further fission chains in the nuclear material. An analysis methodology was demonstrated based on features selected from the simulated correlation functions and on the use of artificial neural networks. We show that the methodology can reliably differentiate between highly enriched uranium and plutonium. Furthermore, the mass of the material can be determined with a relative error of about 12%. Keywords: MCNP, MCNP-PoliMi, Artificial neural network, Correlation measurement, Photofission

Pozzi, Sara A [ORNL; Downar, Thomas J [ORNL; Padovani, Enrico [Nuclear Engineering Department Politecnico di Milano, Milan, Italy; Clarke, Shaun D [ORNL

2006-01-01T23:59:59.000Z

260

Safety and power multiplication aspects of mirror fusion-fission hybrids  

SciTech Connect

Recently, in a research project at Uppsala University a simplified neutronic model for a straight field line mirror hybrid has been devised and its most important operation parameters have been calculated under the constraints of a fission power production of 3 GW and that the effective multiplication factor k{sub eff} does not exceed 0.95. The model can be considered as representative for hybrids driven by other types of mirrors too. In order to reduce the demand on the fusion power of the mirror, a modified option of the hybrid has been considered that generates a reduced fission power of 1.5 GW with an increased maximal value k{sub eff}=0.97. The present paper deals with nuclear safety aspects of this type of hybrids. It presents and discusses calculation results of reactivity effects as well as of driver effects.

Noack, Klaus; Agren, Olov; Kaellne, Jan; Hagnestal, Anders; Moiseenko, Vladimir E. [Uppsala University, Angstroem Laboratory, Division of Electricity, Box 534, SE-751 21 Uppsala (Sweden); Institute of Plasma Physics, National Science Center 'Kharkiv Institute of Physics and Technology', Akademichna St. 1, 61108 Kharkiv (Ukraine)

2012-06-19T23:59:59.000Z

Note: This page contains sample records for the topic "nuclear fission chain" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Delayed-gamma signature calculation for neutron-induced fission and activation using MCNPX, Part I: Theory  

Science Journals Connector (OSTI)

The capability to conduct automated radiation-transport simulations of delayed-gamma emission spectra at discrete (line) energies created by the products of neutron fission and activation has been developed for MCNPX. To do so, the CINDER'90 isotopic transmutation code has been merged into MCNPX to seamlessly supply time-dependent, decay-chain atom densities for 3400 nuclides. A new dataset containing ENDF/B-VI emission-probability line data for 979 nuclides has been created for MCNPX, with the balance of the 3400 nuclides treated using existing 25-group emission spectra. Cumulative distribution sampling functions have been developed to accommodate line and multigroup emission data. Fission-product sampling for fissions induced by sub-20-MeV neutrons uses fission-yield data for thermal (E fission-spectrum (1 eV ? E energy (E ? 14 MeV) neutrons for isotopes of uranium, plutonium, thorium, americium, californium, curium, einsteinium, fermium, and neptunium. For higher-energy neutrons, LAHET, a physics package that is also a part of MCNPX, generates a list of residual nuclides. In Part II, we present simulation results for models based on experiments conducted by Fisher and Engle (1964) and Beddingfield and Cecil (1998) to validate the new capability. As will be seen therein, the MCNPX results are in good agreement with the measured data. Finally, in Part III we augment the Monte Carlo presentation with a transport-theory formulation to provide a succinct encapsulation of the relevant physics. The new MCNPX delayed-gamma development offers a powerful new tool for fission-related signature recognition.

Joe W. Durkee Jr.; Michael R. James; Gregg W. McKinney; Holly R. Trellue; Laurie S. Waters; William B. Wilson

2009-01-01T23:59:59.000Z

262

Safe Chain Saw Operation.  

E-Print Network (OSTI)

Z TA24S.7 8873 NO.1409 B-1409 SAFE CHAIN SAW OPERATION Gary S. Nelson* A chain saw is a portable power cutting machine. Used properly, it will trim or cut down trees, clear land or cut fireplace wood. Improperly used, a chain saw can... ground level , losing balance, shifting chain saw weight while cutting at or above waist level or ex periencing chain saw kickback. Often, loss of balance causes an operator to reach into the running saw blade as he grabs to steady himself. Other...

Nelson, Gary S.

1982-01-01T23:59:59.000Z

263

Bayesian network analysis of nuclear acquisitions  

E-Print Network (OSTI)

(SNM). 5 The definition of SNM currently encompasses plutonium and uranium with the isotopes of uranium-233 (U-233) or uranium-235 (U-235) being enriched to greater than twenty percent. Materials for Nuclear Weapons Uranium is contained in soils... the standpoint of preventing the spread of nuclear weapons, the short list of material usable for this purpose may be confined to those that are used for fission based weapons, uranium and plutonium, which are commonly referred to as Special Nuclear Materials...

Freeman, Corey Ross

2009-05-15T23:59:59.000Z

264

Atom-split it for nuclear energy  

NLE Websites -- All DOE Office Websites (Extended Search)

Atom-split it for nuclear energy Fermi-leader of the team that produced the first self-sustaining controlled nuclear chain reaction; contributed to ending WWII Calutron-invented by...

265

Fission product yields for fast-neutron fission of /sup 243,244,246,248/Cm  

SciTech Connect

Recent measurements of relative yields for /sup 95/Zr, /sup 125/Sb, /sup 137/Cs, /sup 141/Ce, /sup 144/Ce, and /sup 155/Eu for fast-neutron fission of samples enriched in the actinides /sup 243,244,246,248/Cm have been combined with a simple mass-distribution model to predict complete mass distributions for fast-neutron fission of each of these four curium actinides. Complete descriptions of the data analysis and of the model and its application and limitations are given.

Dickens, J.K.

1987-05-01T23:59:59.000Z

266

Ising-Chain Statistics  

Science Journals Connector (OSTI)

The general n-spin correlation function for the Ising chain is calculated exactly. The perpendicular magnetic susceptibility is calculated for arbitrary values of the parallel magnetic field.

James S. Marsh

1966-05-06T23:59:59.000Z

267

SciTech Connect: SPIDER: A Predictive Theory For Fission  

Office of Scientific and Technical Information (OSTI)

Details In-Document Search Title: SPIDER: A Predictive Theory For Fission Authors: White, Morgan C. Los Alamos National Laboratory; Sierk, Arnold John Los Alamos National...

268

Chapter 8 - The history of nuclear energy  

Science Journals Connector (OSTI)

Abstract This chapter reviews the history related to nuclear energy beginning with scientific investigations in the late 1800s that led to the discovery of subatomic particles and both atomic and nuclear structure. Those research efforts spawned the discovery of fission. The Manhattan Project to develop an atomic bomb then accelerated the knowledge base of nuclear phenomena. After World War II, the Atomic Energy Commission was established and later the International Atomic Energy Agency. Research and development efforts led to the deployment of the first nuclear power plants. This chapter ends by addressing the controversies surrounding nuclear energy in the late twentieth century.

Raymond L. Murray; Keith E. Holbert

2015-01-01T23:59:59.000Z

269

The Role of Fission in Neutron Star Mergers and the Position of the Third r-Process Peak  

E-Print Network (OSTI)

The comparison between observational abundance features and those obtained from nucleosynthesis predictions of stellar evolution and/or explosion simulations can scrutinize two aspects: (a) the conditions in the astrophysical production site and (b) the quality of the nuclear physics input utilized. Here we test the abundance features of r-process nucleosynthesis calculations for the dynamical ejecta of neutron star merger simulations based on three different nuclear mass models: The Finite Range Droplet Model (FRDM), the (quenched version of the) Extended Thomas Fermi Model with Strutinsky Integral (ETFSI-Q), and the Hartee-Fock-Bogoliubov (HFB) mass model. We make use of corresponding fission barrier heights and compare the impact of four different fission fragment distribution models on the final r-process abundance distribution. Furthermore, we explore the origin of a shift in the third r-process peak position in comparison with the solar r-process abundances which have been noticed in a number of merger ...

Eichler, Marius; Kelic, Alexandra; Korobkin, Oleg; Langanke, Karlheinz; Martinez-Pinedo, Gabriel; Panov, Igor V; Rauscher, Thomas; Rosswog, Stephan; Winteler, Christian; Zinner, Nikolaj T; Thielemann, Friedrich-Karl

2014-01-01T23:59:59.000Z

270

Nuclear physics information needed for accelerator driven transmutation of nuclear waste  

SciTech Connect

There is renewed interest in using accelerator driven neutron sources to address the problem of high-level long-lived nuclear waste. Several laboratories have developed systems that may have a significant impact on the future use of nuclear power, adding options for dealing with long-lived actinide wastes and fission products, and for power production. This paper describes a new Los Alamos concept using thermal neutrons and examines the nuclear data requirements. 7 refs., 3 figs., 1 tab.

Lisowski, P.W.; Bowman, C.D.; Arthur, E.D.; Young, P.G.

1991-01-01T23:59:59.000Z

271

Selective Trapping of Volatile Fission Products with an Off-Gas Treatment System  

SciTech Connect

A head-end processing step, termed DEOX for its emphasis on decladding via oxidation, is being developed for the treatment of spent oxide fuel by pyroprocessing techniques. The head-end step employs high temperatures to oxidize UO2 to U3O8 resulting in the separation of fuel from cladding and the removal of volatile fission products. Development of the head-end step is being performed in collaboration with the Korean Atomic Energy Research Institute (KAERI) through an International Nuclear Energy Research Initiative. Following the initial experimentation for the removal of volatile fission products, an off-gas treatment system was designed in conjunction with KAERI to collect specific fission gases. The primary volatile species targeted for trapping were iodine, technetium, and cesium. Each species is intended to be collected in distinct zones of the off-gas system and within those zones, on individual filters. Separation of the volatile off-gases is achieved thermally as well as chemically given the composition of the filter media. A description of the filter media and a basis for its selection will be given along with the collection mechanisms and design considerations. In addition, results from testing with the off-gas treatment system will be presented.

B.R. Westphal; J.J. Park; J.M. Shin; G.I. Park; K.J. Bateman; D.L. Wahlquist

2008-07-01T23:59:59.000Z

272

Deep Atomic Binding (DAB) Approach in Interpretation of Fission Products Behavior in Human Body, and Health Consequences  

SciTech Connect

According to models used to predict health effects of fission products enter the human body, a large number of fatalities, malignancies, thyroid cancer, born (genetic) defects,...etc.. But the actual data after Chernobyl and TMI accidents, and nuclear detonations in USA and Marshal Islands, were not consistent with these models. According to DAB, these data could be interpreted, and conflicts between former models predictions and actual field data explained. (author)

Ajlouni, Abdul-Wali M.S. [Ministry of Energy and Mineral Resources, Amman 11814 (Jordan)

2006-07-01T23:59:59.000Z

273

Aqueous Biphasic Systems Based on Salting-Out Polyethylene Glycol or Ionic Solutions: Strategies for Actinide or Fission Product Separations  

SciTech Connect

Aqueous biphasic systems can be formed by salting-out (with kosmotropic, waterstructuring salts) water soluble polymers (e.g., polyethylene glycol) or aqueous solutions of a wide range of hydrophilic ionic liquids based on imidazolium, pyridinium, phosphonium and ammonium cations. The use of these novel liquid/liquid biphases for separation of actinides or other fission products associated with nuclear wastes (e.g., pertechnetate salts) has been demonstrated and will be described in this presentation.

Rogers, Robin D.; Gutowski, Keith E.; Griffin, Scott T.; Holbrey, John D.

2004-03-29T23:59:59.000Z

274

Fission neutron spectra measurements at LANSCE - status and plans  

SciTech Connect

A program to measure fission neutron spectra from neutron-induced fission of actinides is underway at the Los Alamos Neutron Science Center (LANSCE) in a collaboration among the CEA laboratory at Bruyeres-le-Chatel, Lawrence Livermore National Laboratory and Los Alamos National Laboratory. The spallation source of fast neutrons at LANSCE is used to provide incident neutron energies from less than 1 MeV to 100 MeV or higher. The fission events take place in a gas-ionization fission chamber, and the time of flight from the neutron source to that chamber gives the energy of the incident neutron. Outgoing neutrons are detected by an array of organic liquid scintillator neutron detectors, and their energies are deduced from the time of flight from the fission chamber to the neutron detector. Measurements have been made of the fission neutrons from fission of {sup 235}U, {sup 238}U, {sup 237}Np and {sup 239}Pu. The range of outgoing energies measured so far is from 1 MeV to approximately 8 MeV. These partial spectra and average fission neutron energies are compared with evaluated data and with models of fission neutron emission. Results to date will be presented and a discussion of uncertainties will be given in this presentation. Future plans are to make significant improvements in the fission chambers, neutron detectors, signal processing, data acquisition and the experimental environment to provide high fidelity data including mea urements of fission neutrons below 1 MeV and improvements in the data above 8 MeV.

Haight, Robert C [Los Alamos National Laboratory; Noda, Shusaku [Los Alamos National Laboratory; Nelson, Ronald O [Los Alamos National Laboratory; O' Donnell, John M [Los Alamos National Laboratory; Devlin, Matt [Los Alamos National Laboratory; Chatillon, Audrey [CEA-FRANCE; Granier, Thierry [CEA-FRANCE; Taieb, Julien [CEA-FRANCE; Laurent, Benoit [CEA-FRANCE; Belier, Gilbert [CEA-FRANCE; Becker, John A [LLNL; Wu, Ching - Yen [LLNL

2009-01-01T23:59:59.000Z

275

Characterization of nuclear physics targets using Rutherford backscattering and particle induced x-ray emission  

E-Print Network (OSTI)

Rutherford backscattering and particle induced x-ray emission have been utilized to precisely characterize targets used in nuclear fission experiments. The method allows for a fast and non destructive determination of target thickness, homogeneity and element composition.

Th. Rubehn; G. J. Wozniak; L. Phair; L. G. Moretto; Kin M. Yu

1996-09-23T23:59:59.000Z

276

Barloworld Supply Chain Software USA  

E-Print Network (OSTI)

Barloworld Supply Chain Software USA Supply Chain Consultant / Inventory Analyst Position November 2011 #12;Barloworld SCS USA ­ Supply Chain / Inventory Analyst Aug 2011 Page 2 of 4 INTRODUCTION Barloworld Supply Chain Software (SCS) USA would like to invite you to apply for a Supply Chain

Heller, Barbara

277

Research in heavy-ion nuclear physics. Annual progress report, May 1, 1992--April 30, 1993  

SciTech Connect

Attention was focused on the fission process in light nuclear systems. A model calculation based on the transition-state model of nuclear fission was applied to {sup 47}V fission as populated through multiple entrance channels and to fusion-fission cross sections for production of {sup 28}Al through three different entrance channels. Angular distributions are shown for different mass channels of the {sup 29}Si+{sup 27}Al reaction at E{sub lab} = 125 MeV. Pronounced structure is seen in the symmetric and near-symmetric fission channels from the {sup 24}Mg+{sup 24}Mg reaction; cross sections for binary fragment emission are shown for E{sub lab} = 90 MeV. A large Bragg-curve detector was used in this experiment. Ways to optimize detector response were studied; in addition, the Bragg detector was instrumented with an internal position-sensitive multiwire proportional counter.

Sanders, S.J.; Prosser, F.W.

1992-01-01T23:59:59.000Z

278

Chemical factors affecting fission product transport in severe LMFBR accidents  

SciTech Connect

This study was performed as a part of a larger evaluation effort on LMFBR accident, source-term estimation. Purpose was to provide basic chemical information regarding fission product, sodium coolant, and structural material interactions required to perform estimation of fission product transport under LMFBR accident conditions. Emphasis was placed on conditions within the reactor vessel; containment vessel conditions are discussed only briefly.

Wichner, R.P.; Jolley, R.L.; Gat, U.; Rodgers, B.R.

1984-10-01T23:59:59.000Z

279

A Fission-Powered Interstellar Precursor Mission  

SciTech Connect

An 'interstellar precursor mission' lays the groundwork for eventual interstellar exploration by studying the interstellar medium and by stretching technologies that have potential application for eventual interstellar exploration. The numerous scientific goals for such a mission include generating a 3-D stellar map of our galaxy, studying Kuiper-belt and Oort cloud objects, and observing distant objects using the sun's gravitational lens as the primary of an enormous telescope. System equations are developed for a space tug which propels a 2500-kg scientific payload to 550 astronomical units in about 20 years. The tug to transport this payload uses electric propulsion with an Isp of 15,000 seconds and a fission reactor with a closed Brayton cycle to genemte the electricity. The optimal configuration may be to thrust for only about 6 years and then coast for the remaining 14 pars. This spacecraft does not require any physics breakthroughs or major advances in technology. The fission power syslem can be engineered and built by drawing upon known technologies developed for relatgd systems over the past 40 years. The tug system would eventually reach 1000 a.u in 33 years, and would have adequate power to relay large amounts of data throughout its journey.

Lenard, R.X.; Lipinski, R.J.; West, J.L.; Wright, S.A.

1998-10-28T23:59:59.000Z

280

International Nuclear Energy Learning Resources for Home and School (part  

NLE Websites -- All DOE Office Websites (Extended Search)

3 3 Search Go Home Postdocs Students Student Outreach Resources for Schools U.S.-based International (English) International (Other) Events IGED 2013 Science Careers in Search of Women Girls, choose a career in Nuclear Science and Technology! Argonne Nuclear Engineers tell why they chose a Nuclear Career Resources Contact Us Recent Events Science Careers in Search of Women, Apr. 18, 2013 Junior Girl Scout Workshop 'Atomic Fission Fun with the American Nuclear Society', Jan. 26, 2013 Getting to know nuclear energy: the past, the present & the future - free public lecture (Nov. 15, 2012, Argonne National Laboratory) On January 26, 2013, Argonne staff members participated in the Junior Girl Scout Workshop 'Atomic Fission Fun with the American Nuclear Society' organized by the Chicago Section of the American Nuclear Society. Read the

Note: This page contains sample records for the topic "nuclear fission chain" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

International Nuclear Energy Learning Resources for Home and School (part  

NLE Websites -- All DOE Office Websites (Extended Search)

2 2 Search Go Home Postdocs Students Student Outreach Resources for Schools U.S.-based International (English) International (Other) Events IGED 2013 Science Careers in Search of Women Girls, choose a career in Nuclear Science and Technology! Argonne Nuclear Engineers tell why they chose a Nuclear Career Resources Contact Us Recent Events Science Careers in Search of Women, Apr. 18, 2013 Junior Girl Scout Workshop 'Atomic Fission Fun with the American Nuclear Society', Jan. 26, 2013 Getting to know nuclear energy: the past, the present & the future - free public lecture (Nov. 15, 2012, Argonne National Laboratory) On January 26, 2013, Argonne staff members participated in the Junior Girl Scout Workshop 'Atomic Fission Fun with the American Nuclear Society' organized by the Chicago Section of the American Nuclear Society. Read the

282

Research in heavy-ion nuclear physics  

SciTech Connect

This report discusses the following topics: Fusion-fission in light nuclear systems; High-resolution Q-value measurement for the {sup 24}Mg+{sup 24}Mg reaction; Heavy-ion reactions and limits to fusion; and Hybrid MWPC-Bragg curve detector development.

Sanders, S.J.; Prosser, F.W.

1992-01-01T23:59:59.000Z

283

Ceramic Hosts for Fission Products Immobilization  

SciTech Connect

Natural spinel, perovskite and zirconolite rank among the most leach resistant of mineral forms. They also have a strong affinity for a large number of other elements and including actinides. Specimens of natural perovskite and zirconolite were radioisotope dated and found to have survived at least 2 billion years of natural process while still remain their loading of uranium and thorium . Developers of the Synroc waste form recognized and exploited the capability of these minerals to securely immobilize TRU elements in high-level waste . However, the Synroc process requires a relatively uniform input and hot pressing equipment to produce the waste form. It is desirable to develop alternative approaches to fabricate these durable waste forms to immobilize the radioactive elements. One approach is using a high temperature process to synthesize these mineral host phases to incorporate the fission products in their crystalline structures. These mineral assemblages with immobilized fission products are then isolated in a durable high temperature glass for periods measured on a geologic time scale. This is a long term research concept and will begin with the laboratory synthesis of the pure spinel (MgAl2O4), perovskite (CaTiO3) and zirconolite (CaZrTi2O7) from their constituent oxides. High temperature furnace and/or thermal plasma will be used for the synthesis of these ceramic host phases. Nonradioactive strontium oxide will be doped into these ceramic phases to investigate the development of substitutional phases such as Mg1-xSrxAl2O4, Ca1-xSrxTiO3 and Ca1-xSrxZrTi2O7. X-ray diffraction will be used to establish the crystalline structures of the pure ceramic hosts and the substitution phases. Scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDX) will be performed for product morphology and fission product surrogates distribution in the crystalline hosts. The range of strontium doping is planned to reach the full substitution of the divalent metal ions, Mg and Ca, in the ceramic host phases. The immobilization of rear earth (lanthanide series) fission products in these ceramic host phases will also be studied this year. Cerium oxide is chosen to represent the rear earth fission product for substitution studies in spinel, perovskite and zirconolite ceramic hosts. Cerium has +3 and +4 oxidation states and it can replace some of the trivalent or tetravalent host ions to produce the substitution ceramics such as MgAl2-xCexO4, CaTi1-xCexO3, CaZr1-xCexTi2O7 and CaZrTi2-xCexO7. X-ray diffraction analysis will be used to compare the crystalline structures of the pure ceramic hosts and the substitution phases. SEM-EDX analysis will be used to study the Ce distribution in the ceramic host phases. The range of cerium doping is planned to reach the full substitution of the trivalent or tetravalent ions, Al, Ti and Zr, in the ceramic host phases.

Peter C Kong

2010-07-01T23:59:59.000Z

284

Multiple-Coincidence Active Neutron Interrogation of Fissionable Materials  

SciTech Connect

Using a beam of tagged 14.1 MeV neutrons to probe for the presence of fissionable materials, we have measured n-?-? coincidences from depleted uranium (DU). The multiple coincidence rate is substantially above that measured from lead, tungsten, and iron. The presence of coincidences involving delayed gammas in the DU time spectra provides a signature for fissionable materials that is distinct from non-fissionable ones. In addition, the information from the tagged neutron involved in the coincidence gives the position of the fissionable material in all three dimensions. The result is an imaging probe for fissionable materials that is more compact and that produces much less radiation than other solutions.

J.P. Hurley, R.P. Keegan, J.R. Tinsley, R. Trainham, and S.C. Wilde

2008-08-06T23:59:59.000Z

285

Nuclear Energy  

Science Journals Connector (OSTI)

Nuclear Energy ... A brief summary of the history and key concepts of nuclear energy. ... Nuclear / Radiochemistry ...

Charles D. Mickey

1980-01-01T23:59:59.000Z

286

Nuclear batteries  

Science Journals Connector (OSTI)

Nuclear batteries ... Describes the structure, operation, and application of nuclear batteries. ... Nuclear / Radiochemistry ...

Alfred B. Garrett

1956-01-01T23:59:59.000Z

287

Improved Fission Neutron Data Base for Active Interrogation of Actinides  

SciTech Connect

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).

Pozzi, Sara; Czirr, J. Bart; Haight, Robert; Kovash, Michael; Tsvetkov, Pavel

2013-11-06T23:59:59.000Z

288

Nuclear Transport at Low Excitations  

Science Journals Connector (OSTI)

Numerical computations of transport coefficients at low temperatures are presented for shapes typically encountered in nuclear fission. The influence of quantum effects of the nucleonic degrees of freedom is examined, with pair correlations included. Consequences for global collective motion are studied for the case of the decay rate. The range of temperatures is specified above which this motion may be described as a quantal diffusion process.

Helmut Hofmann and Fedor A. Ivanyuk

1999-06-07T23:59:59.000Z

289

Adiabatic description of dissipative processes in heavy-ion reactions and fission. I. Microscopic theory: Statistics of matrix elements  

Science Journals Connector (OSTI)

The statistical properties of matrix elements which couple the collective (or shape) degrees of nuclear motion with the intrinsic degrees of freedom, are evaluated in the adiabatic representation. The results will be used in a future paper for the calculation of transport coefficients which describe the irreversible (dissipative) transfer of energy from the collective degrees of freedom to the intrinsic ones. As input we use a random-matrix model for the residual interaction, and salient properties of single-particle levels in nonspherical potentials.[NUCLEAR REACTIONS Random-matrix model applied to heavy-ion reaction and fission.

M. C. Nemes and Hans. A. Weidenmüller

1981-08-01T23:59:59.000Z

290

Neutron interrogation system using high gamma ray signature to detect contraband special nuclear materials in cargo  

DOE Patents (OSTI)

A system for inspecting cargo for the presence of special nuclear material. The cargo is irradiated with neutrons. The neutrons produce fission products in the special nuclear material which generate gamma rays. The gamma rays are detecting indicating the presence of the special nuclear material.

Slaughter, Dennis R. (Oakland, CA); Pohl, Bertram A. (Berkeley, CA); Dougan, Arden D. (San Ramon, CA); Bernstein, Adam (Palo Alto, CA); Prussin, Stanley G. (Kensington, CA); Norman, Eric B. (Oakland, CA)

2008-04-15T23:59:59.000Z

291

XPS Investigations of Ruthenium Deposited onto Representative Inner Surfaces of Nuclear Reactor Containment Buildings  

E-Print Network (OSTI)

XPS Investigations of Ruthenium Deposited onto Representative Inner Surfaces of Nuclear Reactor in a nuclear power plant, interactions of gaseous RuO4 with reactor containment building surfaces (stainless, during nuclear reactor operation, the fission-product ruthenium will accumulate in the fuel. The quantity

Paris-Sud XI, Université de

292

Nuclear Properties of 93237  

Science Journals Connector (OSTI)

The isotope Np237, produced as the decay product of the previously known 6.8-day U237, has been isolated with carrier material and some of its nuclear properties measured. The U237 was formed by means of the reaction U238(n,2n)U237. Np237 decays with the emission of alphaparticles with a half-life of about 3×106 years. It has been shown that the upper limit for the cross section for the fission of Np237 with slow neutrons is less than 1 percent of that of U235.

Arthur C. Wahl and Glenn T. Seaborg

1948-05-01T23:59:59.000Z

293

Microsoft Word - illinois_reactors_taiwo.doc  

NLE Websites -- All DOE Office Websites (Extended Search)

Fission Process and Control Fission Process and Control In nuclear power reactors, energy is produced by the nuclear fission process in which uranium atoms are split into two major atoms, called fission products, with significant heat generation. A nuclear reactor system is controlled to ensure that the fission process is a sustained nuclear chain reaction (see Fig. 1) that neither declines nor increases with operation time, i.e., it is at

294

European supply chain study  

E-Print Network (OSTI)

Introduction: Supply chain management has been defined as, "..a set of approaches utilized to efficiently integrate suppliers, manufacturers, warehouses and stores, so that merchandise is produced and distributed at the ...

Puri, Mohitkumar

2009-01-01T23:59:59.000Z

295

Nuclear Forensics  

NLE Websites -- All DOE Office Websites (Extended Search)

nuclear forensics Nuclear Forensics AMS is a Powerful Tool for Nuclear Forensics Nuclear forensics, which can be applied to both interdicted materials and debris from a nuclear...

296

A Review of Nuclear Computational Information  

SciTech Connect

The Radiation Safety Information Computational Center (RSICC) and the Organisation for Economic Co-operation and Development (OECD) Nuclear Energy Agency Data Bank (NEADB) work together to acquire sets of computer codes, nuclear data, and integral experiments relevant to shielding and dosimetry applications for fission, fusion, and accelerator applications. To keep up with advances in computing technology, international researchers continue to develop nuclear software. Collection centers like RSICC and NEADB serve the community and play a role in advancing nuclear science and technology research.

Kirk, Bernadette Lugue [ORNL] [ORNL

2010-01-01T23:59:59.000Z

297

Control system for a small fission reactor  

DOE Patents (OSTI)

A system for controlling the reactivity of a small fission reactor includes an elongated, flexible hollow tube in the general form of a helical coiled spring axially positioned around and outside of the reactor vessel in an annular space between the reactor vessel and a surrounding cylindrical-shaped neutron reflector. A neutron absorbing material is provided within the hollow tube with the rate of the reaction controlled by the extension and compression of the hollow tube, e.g., extension of the tube increases reactivity while its compression reduces reactivity, in varying the amount of neutron absorbing material disposed between the reactor vessel and the neutron reflector. Conventional mechanical displacement means may be employed to control the coil density of the hollow tube as desired.

Burelbach, J.P.; Kann, W.J.; Saiveau, J.G.

1985-02-08T23:59:59.000Z

298

(Fuel, fission product, and graphite technology)  

SciTech Connect

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

Stansfield, O.M.

1990-07-25T23:59:59.000Z

299

The Role of Fission in Neutron Star Mergers and the Position of the Third r-Process Peak  

E-Print Network (OSTI)

The comparison between observational abundance features and those obtained from nucleosynthesis predictions of stellar evolution and/or explosion simulations can scrutinize two aspects: (a) the conditions in the astrophysical production site and (b) the quality of the nuclear physics input utilized. Here we test the abundance features of r-process nucleosynthesis calculations for the dynamical ejecta of neutron star merger simulations based on three different nuclear mass models: The Finite Range Droplet Model (FRDM), the (quenched version of the) Extended Thomas Fermi Model with Strutinsky Integral (ETFSI-Q), and the Hartee-Fock-Bogoliubov (HFB) mass model. We make use of corresponding fission barrier heights and compare the impact of four different fission fragment distribution models on the final r-process abundance distribution. Furthermore, we explore the origin of a shift in the third r-process peak position in comparison with the solar r-process abundances which have been noticed in a number of merger nucleosynthesis predictions. We show that this shift occurs during the r-process freeze-out when neutron captures and beta-decays compete and an (n,g)-(g,n) equilibrium is not maintained anymore. During this phase neutrons originate mainly from fission of material above A = 240. We also demonstrate that a faster (and thus earlier) release of these neutrons, e.g., by shorter beta-decay half-lives of nuclei with Z > 80, as suggested by recent theoretical advances, can partially prevent this shift.

Marius Eichler; Almudena Arcones; Alexandra Kelic; Oleg Korobkin; Karlheinz Langanke; Gabriel Martinez-Pinedo; Igor V. Panov; Thomas Rauscher; Stephan Rosswog; Christian Winteler; Nikolaj T. Zinner; Friedrich-Karl Thielemann

2014-11-04T23:59:59.000Z

300

Scission neutron emission and prompt fission neutron spectrum  

E-Print Network (OSTI)

The mass, energy and angular integrated spectra of prompt fission neutrons for sup 2 sup 3 sup 5 U induced fission in the energy range from thermal to 5 MeV were analyzed. It allows assume that about 0.362+-0.025 neutrons per fission are emitted due to another mechanism then neutron emission from excited fragments after full acceleration. The spectrum of scission neutrons consists of two components with average energy 0.98 MeV and 2.74 MeV. The share of scission neutrons and their spectrum shape estimated in this work does not contradict to results of differential experiments analyzed in previous papers.

Kornilov, N V

2001-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "nuclear fission chain" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Methods and apparatuses for the development of microstructured nuclear fuels  

DOE Patents (OSTI)

Microstructured nuclear fuel adapted for nuclear power system use includes fissile material structures of micrometer-scale dimension dispersed in a matrix material. In one method of production, fissile material particles are processed in a chemical vapor deposition (CVD) fluidized-bed reactor including a gas inlet for providing controlled gas flow into a particle coating chamber, a lower bed hot zone region to contain powder, and an upper bed region to enable powder expansion. At least one pneumatic or electric vibrator is operationally coupled to the particle coating chamber for causing vibration of the particle coater to promote uniform powder coating within the particle coater during fuel processing. An exhaust associated with the particle coating chamber and can provide a port for placement and removal of particles and powder. During use of the fuel in a nuclear power reactor, fission products escape from the fissile material structures and come to rest in the matrix material. After a period of use in a nuclear power reactor and subsequent cooling, separation of the fissile material from the matrix containing the embedded fission products will provide an efficient partitioning of the bulk of the fissile material from the fission products. The fissile material can be reused by incorporating it into new microstructured fuel. The fission products and matrix material can be incorporated into a waste form for disposal or processed to separate valuable components from the fission products mixture.

Jarvinen, Gordon D. (Los Alamos, NM); Carroll, David W. (Los Alamos, NM); Devlin, David J. (Santa Fe, NM)

2009-04-21T23:59:59.000Z

302

Other International Nuclear Energy Learning Resources for Home and School -  

NLE Websites -- All DOE Office Websites (Extended Search)

Other International Resources > Part 2 Other International Resources > Part 2 Search Go Home Postdocs Students Student Outreach Resources for Schools U.S.-based International (English) International (Other) Events IGED 2013 Science Careers in Search of Women Girls, choose a career in Nuclear Science and Technology! Argonne Nuclear Engineers tell why they chose a Nuclear Career Resources Contact Us Recent Events Science Careers in Search of Women, Apr. 18, 2013 Junior Girl Scout Workshop 'Atomic Fission Fun with the American Nuclear Society', Jan. 26, 2013 Getting to know nuclear energy: the past, the present & the future - free public lecture (Nov. 15, 2012, Argonne National Laboratory) On January 26, 2013, Argonne staff members participated in the Junior Girl Scout Workshop 'Atomic Fission Fun with the American Nuclear Society'

303

International Nuclear Energy Learning Resources for Home and School -  

NLE Websites -- All DOE Office Websites (Extended Search)

Other International Resources Other International Resources Search Go Home Postdocs Students Student Outreach Resources for Schools U.S.-based International (English) International (Other) Events IGED 2013 Science Careers in Search of Women Girls, choose a career in Nuclear Science and Technology! Argonne Nuclear Engineers tell why they chose a Nuclear Career Resources Contact Us Recent Events Science Careers in Search of Women, Apr. 18, 2013 Junior Girl Scout Workshop 'Atomic Fission Fun with the American Nuclear Society', Jan. 26, 2013 Getting to know nuclear energy: the past, the present & the future - free public lecture (Nov. 15, 2012, Argonne National Laboratory) On January 26, 2013, Argonne staff members participated in the Junior Girl Scout Workshop 'Atomic Fission Fun with the American Nuclear Society'

304

Nuclear Energy Learning Resources for Home and School - Argonne National  

NLE Websites -- All DOE Office Websites (Extended Search)

Schools Schools Search Go Home Postdocs Students Student Outreach Resources for Schools U.S.-based International (English) International (Other) Events IGED 2013 Science Careers in Search of Women Girls, choose a career in Nuclear Science and Technology! Argonne Nuclear Engineers tell why they chose a Nuclear Career Resources Contact Us Recent Events Science Careers in Search of Women, Apr. 18, 2013 Junior Girl Scout Workshop 'Atomic Fission Fun with the American Nuclear Society', Jan. 26, 2013 Getting to know nuclear energy: the past, the present & the future - free public lecture (Nov. 15, 2012, Argonne National Laboratory) On January 26, 2013, Argonne staff members participated in the Junior Girl Scout Workshop 'Atomic Fission Fun with the American Nuclear Society'

305

Destruction of Plutonium and Other Nuclear Waste Materials Using the Accelerator-Driven Transmutation of Waste Concept  

Science Journals Connector (OSTI)

Each large nuclear power plant produces about 300 kilograms of ... about 120 kilograms of long-lived fission product wastes per year, with major constituents in terms ... humans either directly or by clandestine ...

F. Venneri

1997-01-01T23:59:59.000Z

306

Nuclear Fabrication Consortium  

SciTech Connect

This report summarizes the activities undertaken by EWI while under contract from the Department of Energy (DOE) � Office of Nuclear Energy (NE) for the management and operation of the Nuclear Fabrication Consortium (NFC). The NFC was established by EWI to independently develop, evaluate, and deploy fabrication approaches and data that support the re-establishment of the U.S. nuclear industry: ensuring that the supply chain will be competitive on a global stage, enabling more cost-effective and reliable nuclear power in a carbon constrained environment. The NFC provided a forum for member original equipment manufactures (OEM), fabricators, manufacturers, and materials suppliers to effectively engage with each other and rebuild the capacity of this supply chain by : � Identifying and removing impediments to the implementation of new construction and fabrication techniques and approaches for nuclear equipment, including system components and nuclear plants. � Providing and facilitating detailed scientific-based studies on new approaches and technologies that will have positive impacts on the cost of building of nuclear plants. � Analyzing and disseminating information about future nuclear fabrication technologies and how they could impact the North American and the International Nuclear Marketplace. � Facilitating dialog and initiate alignment among fabricators, owners, trade associations, and government agencies. � Supporting industry in helping to create a larger qualified nuclear supplier network. � Acting as an unbiased technology resource to evaluate, develop, and demonstrate new manufacturing technologies. � Creating welder and inspector training programs to help enable the necessary workforce for the upcoming construction work. � Serving as a focal point for technology, policy, and politically interested parties to share ideas and concepts associated with fabrication across the nuclear industry. The report the objectives and summaries of the Nuclear Fabrication Consortium projects. Full technical reports for each of the projects have been submitted as well.

Levesque, Stephen

2013-04-05T23:59:59.000Z

307

IOP PUBLISHING and INTERNATIONAL ATOMIC ENERGY AGENCY NUCLEAR FUSION Nucl. Fusion 50 (2010) 014004 (14pp) doi:10.1088/0029-5515/50/1/014004  

E-Print Network (OSTI)

IOP PUBLISHING and INTERNATIONAL ATOMIC ENERGY AGENCY NUCLEAR FUSION Nucl. Fusion 50 (2010) 014004 of nuclear energy in the form of nuclear fission were established with the nuclear powered submarine Research and Energy®, 48 Oakland Street, Princeton, NJ 08540, USA E-mail: dmeade@pppl.gov Received 6 August

308

nuclear@illinois.edu | 217-333-2295 | npre.illinois.edu 216 Talbot Laboratory, MC 234 | 104 S. Wright Street | Urbana, IL 61801-2935  

E-Print Network (OSTI)

nuclear@illinois.edu | 217-333-2295 | npre.illinois.edu 216 Talbot Laboratory, MC 234 | 104 S: · Production, transport and interactions of radiation with matter · Applications of nuclear processes · Nuclear fission for electric power production nuclear power operations and control · Plasma sciences, applied

Jain, Kanti

309

Determination of fission rate by mean last passage time  

Science Journals Connector (OSTI)

The mean last passage time is introduced instead of the mean first passage time for determining the decay rate of a nucleus after induced fission. The stationary fission rate calculated by the inverse of the mean last passage time at the saddle point is in agreement with the result of Langevin simulations and better than that of the mean first passing time at the scission point. In particular, we take into account the backstreaming effect where test particles pass over the potential barrier multiple times. It is shown that the oscillating time of a hot fissioning system around the saddle point is the longest one in time scales of the fission, thus more neutrons might be emitted during this period.

Jing-Dong Bao and Ying Jia

2004-02-26T23:59:59.000Z

310

Singlet exciton fission : applications to solar energy harvesting  

E-Print Network (OSTI)

Singlet exciton fission transforms a single molecular excited state into two excited states of half the energy. When used in solar cells it can double the photocurrent from high energy photons increasing the maximum ...

Thompson, Nicholas John

2014-01-01T23:59:59.000Z

311

Half life for spontaneous fission of curium-245  

SciTech Connect

A sample of curium-245 of extremely high enrichment was obtained with an electromagnetic separator. The half-life for spontaneous fission was determined by measuring the rate of alpha decay. (AIP)

Druzhinin, A.A.; Polynov, V.N.; Vesnovskii, S.P.; Korochkin, A.M.; Lbov, A.A.; Nikitin, E.A.

1985-02-01T23:59:59.000Z

312

Thermodynamics of fission products in UO2+-x  

SciTech Connect

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

Nerikar, Pankaj V [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

313

Identification of Fissionable Materials Using the Tagged Neutron Technique  

SciTech Connect

This summary describes experiments to detect and identify fissionable materials using the tagged neutron technique. The objective of this work is to enhance homeland security capability to find fissionable material that may be smuggled inside shipping boxes, containers, or vehicles. The technique distinguishes depleted uranium from lead, steel, and tungsten. Future work involves optimizing the technique to increase the count rate by many orders of magnitude and to build in the additional capability to image hidden fissionable materials. The tagged neutron approach is very different to other techniques based on neutron die-away or photo-fission. This work builds on the development of the Associated Particle Imaging (API) technique at the Special Technologies Laboratory (STL) [1]. Similar investigations have been performed by teams at the Oak Ridge National Laboratory (ORNL), the Khlopin Radium Institute in Russia, and by the EURITRACK collaboration in the European Union [2,3,4].

R.P. Keegan, J.P. Hurley, J.R. Tinsley, R. Trainham

2009-06-30T23:59:59.000Z

314

Relationship between Air Concentration of Radioactive Fission Products and Fallout  

Science Journals Connector (OSTI)

... with rain or snow. This seems to be true for recent material from the 'Teapot' tests as well as for old fission products collected between December 1954 and February ...

I. H. BLIFFORD; L. B. LOCKHART; R. A. BAUS

1956-05-26T23:59:59.000Z

315

Spontaneous fission half-lives for ground state nuclides  

SciTech Connect

Measurements of the spontaneous fission half-lives of nuclides of elements Z = 90 to 107 have been compiled and evaluated. Recommended values are presented. 126 refs., 96 tabs.

Holden, N.E. (Brookhaven National Lab., Upton, NY (United States)); Hoffman, D.C. (Lawrence Berkeley Lab., CA (United States))

1991-01-01T23:59:59.000Z

316

Research in heavy-ion nuclear physics. [Dept. of Physics and Astronomy, The Univ. of Kansas, Lawrence, Kansas  

SciTech Connect

Attention was focused on the fission process in light nuclear systems. A model calculation based on the transition-state model of nuclear fission was applied to [sup 47]V fission as populated through multiple entrance channels and to fusion-fission cross sections for production of [sup 28]Al through three different entrance channels. Angular distributions are shown for different mass channels of the [sup 29]Si+[sup 27]Al reaction at E[sub lab] = 125 MeV. Pronounced structure is seen in the symmetric and near-symmetric fission channels from the [sup 24]Mg+[sup 24]Mg reaction; cross sections for binary fragment emission are shown for E[sub lab] = 90 MeV. A large Bragg-curve detector was used in this experiment. Ways to optimize detector response were studied; in addition, the Bragg detector was instrumented with an internal position-sensitive multiwire proportional counter.

Sanders, S.J.; Prosser, F.W.

1992-01-01T23:59:59.000Z

317

Cross section for fast neutron induced /sup 243/Cm fission  

SciTech Connect

The authors discuss a method for measuring the cross section of the fission of curium 243 which either eliminates or corrects for the interference arising from sister isotopes or from the half-life spontaneous fission of this isotope. Soda-lime glass was used as the detector material and uranium 235 as the calibration standard. The irradiation facility is described. Error estimates are given.

Fomushkin, E.F.; Novoselov, G.F.; Vinogradov, Yu.I.; Vyachin, V.N.; Gavrilov, V.V.; Koshelev, A.S.; Polynov, V.N.; Surin, V.M.; Shvetsov, A.M.

1987-10-01T23:59:59.000Z

318

Calculation of Fission Observables Through Event-by-Event Simulation  

SciTech Connect

The increased interest in more exclusive fission observables has demanded more detailed models. We present here a new computational model, FREYA, that aims to met this need by producing large samples of complete fission events from which any observable of interest can then be extracted consistently, including arbitrary correlations. The various model assumptions are described and the potential utility of the model is illustrated by means of several novel correlation observables.

Randrup, J; Vogt, R

2009-06-04T23:59:59.000Z

319

Investigacin Supply chain collaboration  

E-Print Network (OSTI)

. These interactions among firms' decisions ask for alignment and coordination of actions. Therefore, game theory quantities, among others. Nowadays, business decisions are dominated by the globalization of markets, and that the decisions taken by a firm do also affect the performance of the other parties in the supply chain

Boucherie, Richard J.

320

NUFinancials Supply Chain  

E-Print Network (OSTI)

NUFinancials Supply Chain FMS801 & 803 Purchasing Glossary 03/31/2010 © 2010 Northwestern University FMS801 & 803 1 Purchasing Glossary Guide to terms used in iBuyNU and NUFinancials purchasing Term, faculty salary, office supplies. Similar to CUFS Object Code, Revenue Source, and Balance Sheet. Note

Shull, Kenneth R.

Note: This page contains sample records for the topic "nuclear fission chain" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Negotiations Within Supply Chains  

Science Journals Connector (OSTI)

In this paper we consider a negotiation between a supplier and its retailer. Due to the supplier's commitments with other customers the negotiation is about the maximum order quantity the retailer can order at a fixed price. We propose a structuring ... Keywords: capacity, contract, cooperation, negotiations, scenario, supply chain management

Carsten Homburg; Christoph Schneeweiss

2000-05-01T23:59:59.000Z

322

Powering the Nuclear Navy | National Nuclear Security Administration  

NLE Websites -- All DOE Office Websites (Extended Search)

Powering the Nuclear Navy Powering the Nuclear Navy Home > About Us > Our Programs > Powering the Nuclear Navy Powering the Nuclear Navy The Naval Nuclear Propulsion Program provides militarily effective nuclear propulsion plants and ensures their safe, reliable and long-lived operation. This mission requires the combination of fully trained U.S. Navy men and women with ships that excel in endurance, stealth, speed, and independence from supply chains. NNSA's Navy Reactors Program provides the design, development and operational support required to provide militarily effective nuclear propulsion plants and ensure their safe, reliable and long-lived operation. This budget requests more than $1 billion to power a modern nuclear Navy: Continuation of design and development work for the OHIO-class

323

Current projects - Nuclear Data Program, Nuclear Engineering Division  

NLE Websites -- All DOE Office Websites (Extended Search)

Current Projects Current Projects Nuclear Data Program Overview Current Projects & Recent Activities Collaborating Organizations Publications Nuclear Data Measurements (NDM) Reports Experimental Nuclear Data Resources Contact ND Program Related Resources Other Major Programs Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE Division on Flickr Nuclear Data Program Current Projects Bookmark and Share Compilation and evaluation of nuclear structure and decay data for the IAEA coordinated International Nuclear Structure and Decay Data Network. Argonne Nuclear Data Program has the responsibility for evaluations of A=176-179 & 199-209 mass chains. These evaluations are included in the world most completed and comprehensive nuclear structure

324

Nuclear Data Evaluations for Americium Isotopes  

SciTech Connect

Recent upgrades of 241Am, 242mAm, and 240Am nuclear data in the keV - 30-MeV range are described. The new evaluation takes advantage of recent measurements and advances in calculational modeling methods. The model calculations are especially important for the nuclear data of americium isotopes, because few measurements are available. The nuclear-model code GNASH is extensively used for our evaluations. The new evaluations are given for total, fission, capture (n, 2n), and (n, 3n) reaction cross sections, and vp for 241Am and 242mAm. A new evaluation for 240Am is also given by expanding our modeling feasibility.

Kawano, T.; Talou, P.; Chadwick, M.B.; MacFarlane, R.E.; Young, P.G. [T-16 Nuclear Physics, Los Alamos National Laboratory (United States)

2005-05-24T23:59:59.000Z

325

Initiative in Nuclear Theory at the Variable Energy Cyclotron Centre  

E-Print Network (OSTI)

We recall the path breaking contributions of the nuclear theory group of the Variable Energy Cyclotron Centre, Kolkata. From a beginning of just one person in 1970s, the group has steadily developed into a leading group in the country today, with seminal contributions to almost the entire range of nuclear physics, viz., low energy nuclear reactions, nuclear structure, deep inelastic collisions, fission, liquid to gas phase transitions, nuclear matter, equation of state, mass formulae, neutron stars, relativistic heavy ion collisions, medium modification of hadron properties, quark gluon plasma, and cosmology of early universe.

D. K. Srivastava; J. Alam; D. N. Basu; A. K. Chaudhuri; J. N. De; K. Krishan; S. Pal

2005-06-24T23:59:59.000Z

326

Responsible stewardship of nuclear materials  

SciTech Connect

The ability to tap the massive energy potential of nuclear fission was first developed as a weapon to end a terrible world war. Nuclear fission is also a virtually inexhaustible energy resource, and is the only energy supply in certain areas in Russia, Kazakhstan and elsewhere. The potential link between civilian and military applications has been and continues to be a source of concern. With the end of the Cold War, this issue has taken a dramatic turn. The U.S. and Russia have agreed to reduce their nuclear weapons stockpiles by as much as two-thirds. This will make some 100 tonnes of separated plutonium and 500 tonnes of highly enriched uranium available, in a form that is obviously directly usable for weapons. The total world inventory of plutonium is now around 1000 tonnes and is increasing at 60-70 tonnes per year. There is even more highly enriched uranium. Fortunately the correct answer to what to do with excess weapons material is also the most attractive. It should be used and reused as fuel for fast reactors. Material in use (particularly nuclear material) is very easy to monitor and control, and is quite unattractive for diversion. Active management of fissile materials not only makes a major contribution to economic stability and well-being, but also simplifies accountability, inspection and other safeguards processes; provides a revenue stream to pay for the necessary safeguards; and, most importantly, limits the prospective world inventory of plutonium to only that which is used and useful.

Hannum, W.H.

1994-10-01T23:59:59.000Z

327

Investigation of Fission Product Transport into Zeolite-A for Pyroprocessing Waste Minimization  

SciTech Connect

Methods to improve fission product salt sorption into zeolite-A have been investigated in an effort to reduce waste associated with the electrochemical treatment of spent nuclear fuel. It was demonstrated that individual fission product chloride salts were absorbed by zeolite-A in a solid-state process. As a result, recycling of LiCl-KCl appears feasible via adding a zone-freezing technique to the current treatment process. Ternary salt molten-state experiments showed the limiting kinetics of CsCl and SrCl2 sorption into the zeolite. CsCl sorption occurred rapidly relative to SrCl2 with no observed dependence on zeolite particle size, while SrCl2 sorption was highly dependent on particle size. The application of experimental data to a developed reaction-diffusion-based sorption model yielded diffusivities of 8.04 × 10-6 and 4.04 × 10-7 cm2 /s for CsCl and SrCl2, respectively. Additionally, the chemical reaction term in the developed model was found to be insignificant compared to the diffusion term.

James R. Allensworth; Michael F. Simpson; Man-Sung Yim; Supathorn Phongikaroon

2013-02-01T23:59:59.000Z

328

Time features of delayed neutrons and partial emissive-fission cross sections for the neutron-induced fission of {sup 232}Th nuclei in the energy range 3.2-17.9 MeV  

SciTech Connect

The energy dependence of the relative abundances of delayed neutrons and the energy dependence of the half-lives of their precursors in the neutron-induced fission of {sup 232}Th nuclei in the energy range 3.2-17.9 MeV were measured for the first time. A systematics of the time features of delayed neutrons is developed. This systematics makes it possible to estimate the half-life of delayed-neutron precursors as a function of the nucleonic composition of fissile nuclei by using a single parameter set for all nuclides. The energy dependence of the partial cross sections for emissive fission in the reaction {sup 232}Th(n, f) was analyzed on the basis of data obtained for the relative abundances of delayed neutrons and the aforementioned half-lives and on the basis of the created systematics of the time features of delayed neutrons. It was shown experimentally for the first time that the decrease in the cross section after the reaction threshold in the fission of {sup 232}Th nuclei (it has a pronounced first-chance plateau) is not an exclusion among the already studied uranium, plutonium, and curium isotopes and complies with theoretical predictions obtained for the respective nuclei with allowance for shell, superfluid, and collective effects in the nuclear-level density and with allowance for preequilibrium neutron emission

Roshchenko, V. A., E-mail: roshchenko@ippe.ru; Piksaikin, V. M., E-mail: piksa@ippe.ru; Korolev, G. G.; Egorov, A. S., E-mail: egorov@ippe.r [Institute of Physics and Power Engineering (Russian Federation)

2010-06-15T23:59:59.000Z

329

E-Print Network 3.0 - amplitudes spin chains Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

of 12 spins placed in a permanent magnetic field and interact- ing through a weak Ising... nuclear-spin quantum computer in a chain of impurity paramagnetic atoms in a...

330

The Tourism Global Value Chain  

E-Print Network (OSTI)

The Tourism Global Value Chain ECONOMIC UPGRADING AND WORKFORCE DEVELOPMENT Michelle Christian 2011 CENTER on GLOBALIZATION, GOVERNANCE & COMPETITIVENESS #12;The Tourism Global Value Chain: Economic: November 17, 2011 #12;The Tourism Global Value Chain: Economic Upgrading and Workforce Development i Table

Richardson, David

331

Modeling of Fission Gas Release in UO2  

SciTech Connect

A two-stage gas release model was examined to determine if it could provide a physically realistic and accurate model for fission gas release under Prometheus conditions. The single-stage Booth model [1], which is often used to calculate fission gas release, is considered to be oversimplified and not representative of the mechanisms that occur during fission gas release. Two-stage gas release models require saturation at the grain boundaries before gas is release, leading to a time delay in release of gases generated in the fuel. Two versions of a two-stage model developed by Forsberg and Massih [2] were implemented using Mathcad [3]. The original Forsbers and Massih model [2] and a modified version of the Forsberg and Massih model that is used in a commercially available fuel performance code (FRAPCON-3) [4] were examined. After an examination of these models, it is apparent that without further development and validation neither of these models should be used to calculate fission gas release under Prometheus-type conditions. There is too much uncertainty in the input parameters used in the models. In addition. the data used to tune the modified Forsberg and Massih model (FRAPCON-3) was collected under commercial reactor conditions, which will have higher fission rates relative to Prometheus conditions [4].

MH Krohn

2006-01-23T23:59:59.000Z

332

Initial Back-to-Back Fission Chamber Testing in ATRC  

SciTech Connect

Development and testing of in-pile, real-time neutron sensors for use in Materials Test Reactor experiments is an ongoing project at Idaho National Laboratory. The Advanced Test Reactor National Scientific User Facility has sponsored a series of projects to evaluate neutron detector options in the Advanced Test Reactor Critical Facility (ATRC). Special hardware was designed and fabricated to enable testing of the detectors in the ATRC. Initial testing of Self-Powered Neutron Detectors and miniature fission chambers produced promising results. Follow-on testing required more experiment hardware to be developed. The follow-on testing used a Back-to-Back fission chamber with the intent to provide calibration data, and a means of measuring spectral indices. As indicated within this document, this is the first time in decades that BTB fission chambers have been used in INL facilities. Results from these fission chamber measurements provide a baseline reference for future measurements with Back-to-Back fission chambers.

Benjamin Chase; Troy Unruh; Joy Rempe

2014-06-01T23:59:59.000Z

333

Use of Information Theory Concepts for Developing Contaminated Site Detection Method: Case for Fission Product and Actinides Accumulation Modeling  

SciTech Connect

Information theory concepts and their fundamental importance for environmental pollution analysis in light of experience of Chernobyl accident in Belarus are discussed. An information and dynamic models of the radionuclide composition formation in the fuel of the Nuclear Power Plant are developed. With the use of code DECA numerical calculation of actinides (58 isotopes are included) and fission products (650 isotopes are included) activities has been carried out and their dependence with the fuel burn-up of the RBMK-type reactor have been investigated. (authors)

Harbachova, N.V.; Sharavarau, H.A. [Joint Institute of Power and Nuclear Research - 'Sosny' National Academy of Sciences, 99 Academic, A.K. Krasin Str., 220109 Minsk (Belarus)

2006-07-01T23:59:59.000Z

334

MOLYBDENUM IN GLASSES CONTAINING VITRIFIED NUCLEAR R.J. Hand, R.J. Short, S. Morgan, N.C. Hyatt, G. Mbus and W.E. Lee  

E-Print Network (OSTI)

. High level nuclear waste can contain corrosion products, a wide range of fission products, as well) was used (reducing sparge) whereas compressed air (BOC) was used for a neutral atmosphere (air sparge). One

Sheffield, University of

335

Total and spontaneous fission half-lives for americium and curium nuclides  

SciTech Connect

The long-lived nuclides of the americium curium elements are of interest for their use in certain safeguard applications and for nuclear reactor burnup studies in waste management. Recommended values are presented for /sup 241,242m,243/Am, and for /sup 242,243,244,245,246,247,248,250/Cm. These values result from a consistent evaluation of all these half-lives. These preliminary estimates were presented earlier. The uncertainties are provided at the 95% confidence limit for each of the recommended values. It will be noted that many of the recommended errors considerably exceed errors quoted by individual authors in their publication, by up to an order of magnitude, e.g., the total half-life of /sup 242,246,248/Cm and the spontaneous fission half-life of /sup 244/Cm. 65 refs., 18 tabs.

Holden, N.E.

1985-01-01T23:59:59.000Z

336

Modeling of fission product release from HTR (high temperature reactor) fuel for risk analyses  

SciTech Connect

The US and FRG have developed methodologies to determine the performance of and fission product release from TRISO-coated fuel particles under postulated accident conditions. The paper presents a qualitative and quantitative comparison of US and FRG models. The models are those used by General Atomics (GA) and by the German Nuclear Research Center at Juelich (KFA/ISF). A benchmark calculation was performed for fuel temperatures predicted for the US Department of Energy sponsored Modular High Temperature Gas Cooled Reactor (MHTGR). Good agreement in the benchmark calculations supports the on-going efforts to verify and validate the independently developed codes of GA and KFA/ISF. This work was performed under the US/FRG Umbrella Agreement for Cooperation on Gas Cooled Reactor Development. 6 refs., 3 figs., 3 tabs.

Bolin, J.; Verfondern, K.; Dunn, T.; Kania, M.

1989-07-01T23:59:59.000Z

337

An evaluation of thermal modeling techniques utilized for nuclear fuel rods  

E-Print Network (OSTI)

like to thank my graduate advisor, Dr. K. L. Peddicord, for his technical advice and guidance throughout this project and my studies in Nuclear Engineering at Texas AgiM University. Thanks are also extended to Dr. Hassan and Dr. Caton for reviewing.... Burnup Fission Gas Rdease Fuel Tltermal Conductivity Fuel Cracking Fuel Creep Rate Fuel Relocadon Fuel VIrermal Expansion Fuel Rod Tltermal Power Fuel Telltpelanaes Fuel Stress es Fuel Strains Fission Rate Fuel-Cladding Gap Heat...

Simmons, Jeffrey Warren

2012-06-07T23:59:59.000Z

338

Nuclear Engineering and Design 55 (1979) 69-95 North-Holland Publishing Company  

E-Print Network (OSTI)

Nuclear Engineering and Design 55 (1979) 69-95 © North-Holland Publishing Company A DYNAMIC INTRAGRANULAR FISSION GAS BEHAVIOR MODEL J.M. GRIESMEYER, N,M. GHONIEM and D. OKRENT Chemical Nuclear and Thermal Engineering Department, University of California,Los Angeles, Los Angeles, California 90024, USA

Ghoniem, Nasr M.

339

Toward Designed Singlet Fission: Electronic States and Photophysics of  

NLE Websites -- All DOE Office Websites (Extended Search)

Designed Singlet Fission: Electronic States and Photophysics of Designed Singlet Fission: Electronic States and Photophysics of 1,3-Diphenylisobenzofuran Andrew F. Schwerin, Justin C. Johnson, Millicent B. Smith, Paiboon Sreearunothai, Duska Popovic, Jiri Cerny, Zdenek Havlas, Irina Paci, Akin Akdag, Matthew K. MacLeod, Xudong Chen, Donald E. David, Mark A. Ratner, John R. Miller, Arthur J. Nozik and Josef Michl J. Phys. Chem. A 114, 1457-1473 (2010). [Find paper at ACS Publications] Abstract: Single crystal molecular structure and solution photophysical properties are reported for 1,3-diphenylisobenzofuran (1), of interest as a model compound in studies of singlet fission. For the ground state of 1 and of its radical cation (1+*) and anion (1-*), we report the UV-visible absorption spectra, and for neutral 1, also the magnetic

340

Chapter 17 - Nuclear Fusion  

Science Journals Connector (OSTI)

Publisher Summary Nuclear fusion, the joining of light nuclei of hydrogen into heavier nuclei of helium, has potential environmental, safety and proliferation characteristics as an energy source, as well as adequate fuel to power civilization for times long compared to human history. It is, however, more challenging to convert to an energy source than nuclear fission. This chapter introduces the physics, advantages, difficulties, progress, economics and prospects for fusion energy power plants. Nuclear fusion is the process, in which light nuclei can release large amounts of energy if they combine, or fuse, into heavier nuclei. The principal nuclear reactions which have been considered for reactor concepts involve reactions of isotopes of the two lightest elements: hydrogen and helium. The fuel costs for fusion reactors will be negligible in comparison with the value of the electricity produced. It is difficult to precisely assess the cost of fusion-generated electricity until there is experience with an operating power plant, since the cost will be dependent upon the reliability and the frequency and expense of maintenance, both of which are likely to improve with the hindsight of experience. A fusion reactor does not directly emit CO2 or other greenhouse gases, or any combustion products that contribute to acid rain, and the indirect emissions due to factors like fuel gathering and transport, plant construction and maintenance, and activated parts storage would be small. Thus, fusion power would not have appreciable adverse effects upon global warming, atmospheric quality or acidification of the oceans, lakes and streams.

Larry R. Grisham

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "nuclear fission chain" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Contact Us | National Nuclear Security Administration  

National Nuclear Security Administration (NNSA)

The National Nuclear Security Administration The National Nuclear Security Administration Contact Us Home > About Us > Our Programs > Defense Programs > Future Science & Technology Programs > Office of Advanced Simulation and Computing and Institutional R&D Programs > Institutional Research & Development > Contact Us Contact Us Above Image: Fission neutrons can be distinguished from background radiation using a novel variation of a metal-organic framework (MOF) scintillator that was a new class of scintillator previously patented by Sandia: Crystals of a metal organic framework (left) emit light in the blue (middle) when exposed to ionizing radiation. Infiltrating them with an organometallic compound causes the crystals to emit red light as well (right), creating a new way to differentiate fission neutrons from

342

Fusion Hindrance and Quasi-Fission in 48Ca Induced Reactions  

Science Journals Connector (OSTI)

...February 2004 research-article Articles Fusion Hindrance and Quasi-Fission in 48Ca Induced Reactions...INFN-Sezione di Napoli, I-80126, Napoli, Italy. Fusion-fission and fusion-evaporation cross sections have been measured in......

Monica Trotta; A. M. Stefanini; B. R. Behera; L. Corradi; E. Fioretto; A. Gadea; S. Szilner; Y. W. Wu; S. Beghini; G. Montagnoli; F. Scarlassara; A. Yu. Chizhov; I. M. Itkis; G. N. Kniajeva; N. A. Kondratiev; E. M. Kozulin; I. V. Pokrovsky; R. N. Sagaidak; V. M. Voskressensky; F. Haas; N. Rowley

2004-02-01T23:59:59.000Z

343

E-Print Network 3.0 - asymmetric fission barriers Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

POLONICA B No 4 BIMODAL FISSION Summary: modes allows to describe observed asymmetric fis- sion of 256 Fm, as well as bimodal fission of 258 Fm... - particle states for the...

344

E-Print Network 3.0 - actinides fission products Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

fission with a large mass asymmetry within the self-consistent HFB theory. A new fis- sion valley... of this fission mode corresponds to the expected one in cluster...

345

A Model for Water Factor Measurements With Fission-Neutron Logging...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

A Model for Water Factor Measurements With Fission-Neutron Logging Tools (May 1983) A Model for Water Factor Measurements With Fission-Neutron Logging Tools (May 1983) A Model for...

346

U.S. Nuclear Energy Learning Resources for Home and School (part 5) -  

NLE Websites -- All DOE Office Websites (Extended Search)

5) 5) Search Go Home Postdocs Students Student Outreach Resources for Schools U.S.-based International (English) International (Other) Events IGED 2013 Science Careers in Search of Women Girls, choose a career in Nuclear Science and Technology! Argonne Nuclear Engineers tell why they chose a Nuclear Career Resources Contact Us Recent Events Science Careers in Search of Women, Apr. 18, 2013 Junior Girl Scout Workshop 'Atomic Fission Fun with the American Nuclear Society', Jan. 26, 2013 Getting to know nuclear energy: the past, the present & the future - free public lecture (Nov. 15, 2012, Argonne National Laboratory) On January 26, 2013, Argonne staff members participated in the Junior Girl Scout Workshop 'Atomic Fission Fun with the American Nuclear Society' organized by the Chicago Section of the American Nuclear Society. Read the

347

U.S. Nuclear Energy Learning Resources for Home and School (part 2) -  

NLE Websites -- All DOE Office Websites (Extended Search)

2) 2) Search Go Home Postdocs Students Student Outreach Resources for Schools U.S.-based International (English) International (Other) Events IGED 2013 Science Careers in Search of Women Girls, choose a career in Nuclear Science and Technology! Argonne Nuclear Engineers tell why they chose a Nuclear Career Resources Contact Us Recent Events Science Careers in Search of Women, Apr. 18, 2013 Junior Girl Scout Workshop 'Atomic Fission Fun with the American Nuclear Society', Jan. 26, 2013 Getting to know nuclear energy: the past, the present & the future - free public lecture (Nov. 15, 2012, Argonne National Laboratory) On January 26, 2013, Argonne staff members participated in the Junior Girl Scout Workshop 'Atomic Fission Fun with the American Nuclear Society' organized by the Chicago Section of the American Nuclear Society. Read the

348

Generating the Option of a Two-Stage Nuclear Renaissance  

Science Journals Connector (OSTI)

...be refueled while remaining online (LWRs have...distributed fission gas bubbles and oxides, and...long-term storage. Life extension. This...16) (which have remaining design work to be...the fueled-for-life core, that is, a nuclear...island” (the turbine and generator...

Robin W. Grimes; William J. Nuttall

2010-08-13T23:59:59.000Z

349

Uncertainties in the Anti-neutrino Production at Nuclear Reactors  

E-Print Network (OSTI)

Anti-neutrino emission rates from nuclear reactors are determined from thermal power measurements and fission rate calculations. The uncertainties in these quantities for commercial power plants and their impact on the calculated interaction rates in electron anti-neutrino detectors is examined. We discuss reactor-to-reactor correlations between the leading uncertainties and their relevance to reactor anti-neutrino experiments.

Z. Djurcic; J. A. Detwiler; A. Piepke; V. R. Foster Jr.; L. Miller; G. Gratta

2008-08-06T23:59:59.000Z

350

Generating the Option of a Two-Stage Nuclear Renaissance  

Science Journals Connector (OSTI)

...inhomogeneously distributed fission gas bubbles and oxides, and noble metal precipitates...conventional “island” (the turbine and generator). At the end of its...coproduct of nonrenewable natural gas), although various measures such as cooling...International Forum, “A Technology Roadmap for Generation IV Nuclear Energy...

Robin W. Grimes; William J. Nuttall

2010-08-13T23:59:59.000Z

351

Nuclear models relevant to evaluation  

SciTech Connect

The widespread use of nuclear models continues in the creation of data evaluations. The reasons include extension of data evaluations to higher energies, creation of data libraries for isotopic components of natural materials, and production of evaluations for radiative target species. In these cases, experimental data are often sparse or nonexistent. As this trend continues, the nuclear models employed in evaluation work move towards more microscopically-based theoretical methods, prompted in part by the availability of increasingly powerful computational resources. Advances in nuclear models applicable to evaluation will be reviewed. These include advances in optical model theory, microscopic and phenomenological state and level density theory, unified models that consistently describe both equilibrium and nonequilibrium reaction mechanism, and improved methodologies for calculation of prompt radiation from fission. 84 refs., 8 figs.

Arthur, E.D.; Chadwick, M.B.; Hale, G.M.; Young, P.G.

1991-01-01T23:59:59.000Z

352

Singlet fission efficiency in tetracene-based organic solar cells  

SciTech Connect

Singlet exciton fission splits one singlet exciton into two triplet excitons. Using a joint analysis of photocurrent and fluorescence modulation under a magnetic field, we determine that the triplet yield within optimized tetracene organic photovoltaic devices is 153%?±?5% for a tetracene film thickness of 20?nm. The corresponding internal quantum efficiency is 127%?±?18%. These results are used to prove the effectiveness of a simplified triplet yield measurement that relies only on the magnetic field modulation of fluorescence. Despite its relatively slow rate of singlet fission, the measured triplet yields confirm that tetracene is presently the best candidate for use with silicon solar cells.

Wu, Tony C., E-mail: tonyw@mit.edu; Thompson, Nicholas J.; Congreve, Daniel N.; Hontz, Eric; Yost, Shane R.; Van Voorhis, Troy; Baldo, Marc A., E-mail: baldo@mit.edu [Energy Frontier Research Center for Excitonics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2014-05-12T23:59:59.000Z

353

Spontaneous-fission branching in the decay of 104259  

Science Journals Connector (OSTI)

The nuclide 104259 has been produced in the Cf249(C13,3n) reaction. Alpha particle groups of 8.77±0.01 MeV and 8.87±0.01 MeV were attributed to the decay of 104159, and the measured half-life was found to be 3.0±1.3 s. The branching ratio for spontaneous fission decay was determined to be 0.063±0.037.RADIOACTIVITY, FISSION 104259(sf and ?), measured T12, E?, I?, Isf, ? for Cf249(C13,3n) and Cf249(C13,?2n) reactions; deduced sf? for 104259; enriched target.

C. E. Bemis; Jr.; P. F. Dittner; R. L. Ferguson; D. C. Hensley; F. Plasil; F. Pleasonton

1981-01-01T23:59:59.000Z

354

Evidence for Conical Intersection Dynamics Mediating Ultrafast Singlet Exciton Fission  

E-Print Network (OSTI)

and highly efficient. For instance, thin films of pentacene and TIPS-pentacene exhibit triplet formation with a time constant of 80 fs and yields of 200%2,3. Current interest in this phenomenon is driven by its potential to circumvent the Shockley... -Queisser limit for single-junction solar cells. By converting high-energy photons into two low-energy excited states, singlet fission offers a means to overcome thermalisation losses. Devices based on pentacene, a fission sensitiser, have demonstrated external...

Musser, Andrew J.; Liebel, Matz; Schnedermann, Christoph; Wende, Torsten; Kehoe, Tom B.; Rao, Akshay; Kukura, Philipp

2015-01-01T23:59:59.000Z

355

Fission cross section calculations of actinides with EMPIRE code  

SciTech Connect

The cross sections of the neutron induced reactions on {sup 233,234,236}U, {sup 237}Np, {sup 238,242}Pu, {sup 241,243}Am, {sup 242,246}Cm carried out in the energy range 1 keV-20 MeV with EMPIRE code are presented, emphasizing the fission channel. Beside a consistent, accurate set of evaluations, the paper contains arguments supporting the choice of the reaction models and input parameters. A special attention is paid to the fission parameters and their uncertainties.

Sin, M.; Oblozinsky, P.; Herman,M.; Capote,R.

2010-04-30T23:59:59.000Z

356

Recent progress in the study of fission barriers in covariant density functional theory  

E-Print Network (OSTI)

Recent progress in the study of fission barriers of actinides and superheavy nuclei within covariant density functional theory is overviewed.

A. V. Afanasjev; H. Abusara; P. Ring

2012-05-10T23:59:59.000Z

357

Fission fragment angular distributions in the Be9 + Th232 reaction  

Science Journals Connector (OSTI)

Fission fragment angular distributions have been measured for a Be9 + Th232 system at four different beam energies around the Coulomb barrier. The experimental results on fission fragment anisotropies have been compared with predictions of the standard statistical saddle-point model (SSPM) and the preequilibrium fission (PEQ) model including projectile ground-state spin. It is observed that both SSPM and the PEQ model fail to reproduce the experimental results, indicating that projectile breakup may affect the fission fragment anisotropies.

S. Appannababu, R. G. Thomas, L. S. Danu, P. K. Rath, Y. K. Gupta, B. V. John, B. K. Nayak, D. C. Biswas, A. Saxena, S. Mukherjee, and R. K. Choudhury

2011-06-09T23:59:59.000Z

358

E-Print Network 3.0 - advanced fission reactors Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

fission reactors, which release energy by splitting atoms... ) International Thermonuclear Experimental Reactor (ITER), which will be ... Source: Fusiongnition Research...

359

Some Spectroscopic Properties of Fine Structures Observed near the Pa231(n,f) Fission Threshold  

Science Journals Connector (OSTI)

The Pa231 neutron-induced fission cross section from 140 to 400 keV was resolved into finer structures. For some of the fractionated vibrational resonances in this energy region, the assignment of spectroscopic parameters may support evidence for an asymmetrically deformed third minimum in the Pa232 fission barrier. Also, for the first time, narrow fission resonances are observed above 1.3 eV exhibiting an average fission width ??f?ob s=8 ?eV.

S. Plattard; G. F. Auchampaugh; N. W. Hill; G. de Saussure; J. A. Harvey; R. B. Perez

1981-03-09T23:59:59.000Z

360

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

SciTech Connect

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

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

1983-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "nuclear fission chain" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Nuclear Energy  

NLE Websites -- All DOE Office Websites (Extended Search)

Research Programs >> Nuclear Energy Error Error Nuclear Energy Home - RCC cannot be displayed due to a timeout error. We recommend: * Refresh Nuclear Energy Home - RCC * Increasing...

362

Fission Product Ratios as Treaty Monitoring Discriminants  

SciTech Connect

The International Monitoring System (IMS) of the Comprehensive Test Ban Treaty Organization (CTBTO) is currently under construction. The IMS is intended for monitoring of nuclear explosions. The radionuclide branch of the IMS monitors the atmosphere for short-lived radioisotopes indicative of a nuclear weapon test, and includes field collection and measurement stations, as well as laboratories to provide reanalysis of the most important samples and a quality control function. The Pacific Northwest National Laboratory in Richland, Washington hosts the United States IMS laboratory, with the designation “RL16.” Since acute reactor containment failures and chronic reactor leakage may also produce similar isotopes, it is tempting to compute ratios of detected isotopes to determine the relevance of an event to the treaty or agreement in question. In this paper we will note several shortcomings of simple isotopic ratios: (1) fractionation of different chemical species, (2) difficulty in comparing isotopes within a single element, (3) the effect of unknown decay times. While these shortcomings will be shown in the light of an aerosol sample, several of the problems extend to xenon isotopic ratios. The result of the difficulties listed above is that considerable human expertise will be required to convert a simple mathematical ratio into a criterion which will reliably categorize an event as ‘reactor’ or ‘weapon’.

Miley, Harry S.; Bowyer, Ted W.; Greenwood, Lawrence R.; Arthur, Richard J.

2008-05-15T23:59:59.000Z

363

chain 2chain 3 4row of 6 racks and 2 row of 5 racks  

E-Print Network (OSTI)

chain 1 chain 2chain 3 4row of 6 racks and 2 row of 5 racks chain 4 chain 10 6 5 4 3 2 1 chain 5 chain 6 f b fb f b b f f b b f 1 2 3 4 5 6 1 2 3 4 5 1:50 Rack A with 52 HU (2500*900*600) door door HV.0 1840.0 300.0 #12;chain 10 Layout of 2nd floorchain 4 chain 3 chain 2 chain 5 chain 6 chain 101:50 Rack

364

Protein-driven membrane stresses in fusion and fission  

E-Print Network (OSTI)

hypotheses on how specific proteins act in the two types of membrane remodeling. Mechanics of fusionProtein-driven membrane stresses in fusion and fission Michael M. Kozlov1 , Harvey T. McMahon2 undergo continuous remodeling. Ex- ocytosis and endocytosis, mitochondrial fusion and fis- sion, entry

McMahon, Harvey

365

Fission-suppressed hybrid reactor: the fusion breeder  

SciTech Connect

Results of a conceptual design study of a /sup 233/U-producing fusion breeder are presented. The majority of the study was devoted to conceptual design and evaluation of a fission-suppressed blanket and to fuel cycle issues such as fuel reprocessing, fuel handling, and fuel management. Studies in the areas of fusion engineering, reactor safety, and economics were also performed.

Moir, R.W.; Lee, J.D.; Coops, M.S.

1982-12-01T23:59:59.000Z

366

The translational landscape of fission yeast meiosis and sporulation  

E-Print Network (OSTI)

of multiple regulatory layers shapes gene expression in fission yeast. Mol Cell 26, 145-55 (2007). 24. Matia-Gonzalez, A.M., Hasan, A., Moe, G.H., Mata, J. & Rodriguez-Gabriel, M.A. Functional characterization of Upf1 targets in Schizosaccharomyces pombe...

Duncan, Caia D. S.; Mata, Juan

2014-06-15T23:59:59.000Z

367

Spallation-Fission Competition in Heavy-Element Reactions: Th232+He4 and U233+d  

Science Journals Connector (OSTI)

Cross sections and excitation functions have been determined for spallation and fission products from bombardments of Th232 with helium ions (15 to 46 Mev) and U233 with deuterons (9 to 24 Mev). This work extends a series of investigations of charged particle (?, d, and p) induced reactions in heavy elements (Z?88). Radiochemical methods were employed to isolate products corresponding to the following spallation reactions: neutron emission, (?, 4n), (?, 5n), (d, n), (d, 2n), and (d, 3n); emission of one proton and neutrons (?, p), (?, pn), (?, p2n), and (?, p3n); and emission of two protons and neutrons, (?, 2p), (?, 2pn), and (?, ?n), and (d, ?n). In addition, the following fission products were isolated from one or more bombardments: Zn72, Ge77, As77, Br82,83, Rb86, Sr89,91, Y93, Zr95,97, Nb96, Mo99, Ru103,105,106, Pd109,112, Ag111, Cd115,115m,117, I131,133, Cs136, Ba139,140, La140, Ce141,143,144, Nd147, Eu157, and Gd159.The results show that fission is the predominant reaction at all energies for Th232 and to an even greater extent for U233. The data for the surviving spallation products are consistent with several mechanisms of reaction, including compound-nucleus formation and evaporation, direct interactions between nucleons of the incoming helium ion or deuteron and nucleons of the nucleus, and a combination of these types of processes (direct interaction followed by evaporation). In general, the results confirm and extend previously established concepts.The neutron-emission spallation reactions as well as fission are best explained as proceeding through compound-nucleus formation. The shapes and magnitudes of (?, 4n), (d, 2n), and (d, 3n) excitation functions correlate well with a compound-nucleus treatment modified to include fission competition. According to this treatment, ratios of neutron to total-reaction level width, ?n?i?i, are 0.49 for U236-233 [from Th232(?, 4n)], 0.17 for Np235-234 [from U233(d, 2n)], and 0.20 for Np235-233 [from U233(d, 3n)]. In addition the total-reaction excitation functions (consisting mostly of the fission excitation functions) are consistent with theoretical cross sections for compound-nucleus formation calculated with a nuclear radius parameter r0=1.5×10-13A13.The fission mass-yield curves are similar to those found for other heavy target isotopes (for elements from thorium to plutonium). The minimum in the curves in the region of mass 120 tends to disappear as helium-ion or deuteron energy is increased.The (?, pxn), (?, 2pxn), (?, ?n), (d, n), and (d, ?n) products are attributed to direct interactions, with complex particles emitted in preference to a series of protons and neutrons. Thus (?, d), (?, t), and (?, tn) mechanisms would account for most of the (?, pn), (?, p2n), and (?, p3n) products, respectively. In the case of the (?, t) and (?, tn) reactions, analysis of the ratio ?(?, tn)?(?, t) leads one to the conclusion that with 35-Mev helium ions only 9% of outgoing tritons leave the residual nucleus with sufficient energy to evaporate a neutron or undergo fission, and with 44-Mev helium ions only 20% do so. The (d, n) product probably results from the stripping reaction.

Bruce M. Foreman, Jr., Walter M. Gibson, Richard A. Glass, and Glenn T. Seaborg

1959-10-15T23:59:59.000Z

368

Fission cross sections up to 20 MeV/nucleon  

Science Journals Connector (OSTI)

Fission cross sections have been measured for the following reactions: C12(at Eb=95, 122, 186, 245, and 291 MeV) on Yb174, Pt198, and U238; O16 (at Eb=140, 175, 216, 250, and 315 MeV) on Nd142, Er170, Os192, and U238; S32 (at Eb=350, 500, and 700 MeV) on Te126, Nd144, and U238; and Ni58 (at Eb=352 and 875 MeV) on Zr96, Cd116, and U238. We find that use of statistical model calculations with the Bass heavy-ion potential, which fit the data below 10 MeV/nucleon, do not fit fission cross sections at higher energies. Invoking dynamical limitations to fusion such as "extra-push" model calculations improves the fit to most of the data. For C12 and O16 projectiles on lighter targets, the fission cross section at higher energies is significantly below the value obtained from the rotating liquid drop angular momentum limit, indicating that incomplete fusion reactions may be limiting the fusion process. For S and Ni projectiles, the cross section implies the existence of a composite system sustaining angular momenta far above the limit beyond which, on the basis of liquid drop model predictions, compound nuclei are not expected to have a finite fission barrier. The angular distribution of fission fragments in C12 and O16-induced reactions has been measured and compared to calculated values. Discrepancies between the measurements and calculated values infer conditions for the breakdown of the transition state model.

A. Gavron; J. Boissevain; H. C. Britt; K. Eskola; P. Eskola; M. M. Fowler; H. Ohm; J. B. Wilhelmy; T. C. Awes; R. L. Ferguson; F. E. Obenshain; F. Plasil; G. R. Young; S. Wald

1984-11-01T23:59:59.000Z

369

Nuclear Debate  

Science Journals Connector (OSTI)

Nuclear Debate ... This month, the Senate will consider the nominations of two women to serve on the Nuclear Regulatory Commission. ... Svinicki is a nuclear engineer with experience in the Department of Energy’s nuclear energy programs. ...

JEFF JOHNSON

2012-06-11T23:59:59.000Z

370

Fission Product Data Measured at Los Alamos for Fission Spectrum and Thermal Neutrons on {sup 239}Pu, {sup 235}U, {sup 238}U  

SciTech Connect

We describe measurements of fission product data at Los Alamos that are important for determining the number of fissions that have occurred when neutrons are incident on plutonium and uranium isotopes. The fission-spectrum measurements were made using a fission chamber designed by the National Institute for Standards and Technology (NIST) in the BIG TEN critical assembly, as part of the Inter-laboratory Liquid Metal Fast Breeder Reactor (LMFBR) Reaction Rate (ILRR) collaboration. The thermal measurements were made at Los Alamos' Omega West Reactor. A related set of measurements were made of fission-product ratios (so-called R-values) in neutron environments provided by a number of Los Alamos critical assemblies that range from having average energies causing fission of 400-600 keV (BIG TEN and the outer regions of the Flattop-25 assembly) to higher energies (1.4-1.9 MeV) in the Jezebel, and in the central regions of the Flattop-25 and Flattop-Pu, critical assemblies. From these data we determine ratios of fission product yields in different fuel and neutron environments (Q-values) and fission product yields in fission spectrum neutron environments for {sup 99}Mo, {sup 95}Zr, {sup 137}Cs, {sup 140}Ba, {sup 141,143}Ce, and {sup 147}Nd. Modest incident-energy dependence exists for the {sup 147}Nd fission product yield; this is discussed in the context of models for fission that include thermal and dynamical effects. The fission product data agree with measurements by Maeck and other authors using mass-spectrometry methods, and with the ILRR collaboration results that used gamma spectroscopy for quantifying fission products. We note that the measurements also contradict earlier 1950s historical Los Alamos estimates by {approx}5-7%, most likely owing to self-shielding corrections not made in the early thermal measurements. Our experimental results provide a confirmation of the England-Rider ENDF/B-VI evaluated fission-spectrum fission product yields that were carried over to the ENDF/B-VII.0 library, except for {sup 99}Mo where the present results are about 4%-relative higher for neutrons incident on {sup 239}Pu and {sup 235}U. Additionally, our results illustrate the importance of representing the incident energy dependence of fission product yields over the fast neutron energy range for high-accuracy work, for example the {sup 147}Nd from neutron reactions on plutonium. An upgrade to the ENDF library, for ENDF/B-VII.1, based on these and other data, is described in a companion paper to this work.

Selby, H.D., E-mail: hds@lanl.go [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Mac Innes, M.R.; Barr, D.W.; Keksis, A.L.; Meade, R.A.; Burns, C.J.; Chadwick, M.B.; Wallstrom, T.C. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

2010-12-15T23:59:59.000Z

371

Corrosion of Spent Nuclear Fuel: The Long-Term Assessment  

SciTech Connect

Spent nuclear fuel, essentially U{sub 2}, accounts for over 95% of the total radioactivity of all of the radioactive wastes in the United States that require disposal, disposition or remediation. The UO{sub 2} in SNF is not stable under oxiding conditions and may also be altered under reducing conditions. The alteration of SNF results in the formation of new uranium phases that can cause the release or retardation of actinide and fission product radionuclides. Over the long term, and depending on the extent to which the secondary uranium phases incorporate fission products and actinides, these alteration phases become the near-field source term.

Rodney C. Ewing

2004-10-07T23:59:59.000Z

372

Spectral Structure of Electron Antineutrinos from Nuclear Reactors  

E-Print Network (OSTI)

Recent measurements of the positron energy spectrum obtained from inverse beta decay interactions of reactor electron antineutrinos show an excess in the 4 to 6 MeV region relative to current predictions. First-principle calculations of fission and beta decay processes within a typical pressurized water reactor core identify prominent fission daughter isotopes as a possible origin for this excess. These calculations also predict percent-level substructure in the antineutrino spectrum due to Coulomb effects in beta decay. Precise measurement of this substructure can constrain nuclear reactor physics. The substructure can be a systematic uncertainty for measurements utilizing the detailed spectral shape.

D. A. Dwyer; T. J. Langford

2014-07-04T23:59:59.000Z

373

Innovative nuclear thermal propulsion technology evaluation: Results of the NASA/DOE Task Team study  

SciTech Connect

In response to findings from two NASA/DOE nuclear propulsion workshops held in the summer of 1990, six task teams were formed to continue evaluation of various nuclear propulsion concepts. The Task Team on Nuclear Thermal Propulsion (NTP) created the Innovative Concepts Subpanel to evaluate thermal propulsion concepts which did not utilize solid fuel. The Subpanel endeavored to evaluate each of the concepts on a level technological playing field,'' and to identify critical technologies, issues, and early proof-of-concept experiments. The concepts included the liquid core fission, the gas core fission, the fission foil reactors, explosively driven systems, fusion, and antimatter. The results of the studies by the panel will be provided. 13 refs., 6 figs., 2 tabs.

Howe, S. (Los Alamos National Lab., NM (United States)); Borowski, S. (National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center); Motloch, C. (EG and G Idaho, Inc., Idaho Falls, ID (United States)); Helms, I. (Nuclear Utility Services, Damascus, MD (United States)); Diaz, N.; Anghaie, S. (Florida Univ., Gainesville, FL (United States)); Latham, T. (United

1991-01-01T23:59:59.000Z

374

U.S. Nuclear Energy Learning Resources for Home and School - Argonne  

NLE Websites -- All DOE Office Websites (Extended Search)

U.S. Resources (Part 1) U.S. Resources (Part 1) Search Go Home Postdocs Students Student Outreach Resources for Schools U.S.-based International (English) International (Other) Events IGED 2013 Science Careers in Search of Women Girls, choose a career in Nuclear Science and Technology! Argonne Nuclear Engineers tell why they chose a Nuclear Career Resources Contact Us Recent Events Science Careers in Search of Women, Apr. 18, 2013 Junior Girl Scout Workshop 'Atomic Fission Fun with the American Nuclear Society', Jan. 26, 2013 Getting to know nuclear energy: the past, the present & the future - free public lecture (Nov. 15, 2012, Argonne National Laboratory) On January 26, 2013, Argonne staff members participated in the Junior Girl Scout Workshop 'Atomic Fission Fun with the American Nuclear Society'

375

Nuclear Energy Density Optimization: UNEDF2  

E-Print Network (OSTI)

The parameters of the UNEDF2 nuclear energy density functional (EDF) model were obtained in an optimization to experimental data consisting of nuclear binding energies, proton radii, odd-even mass staggering data, fission-isomer excitation energies, and single particle energies. In addition to parameter optimization, sensitivity analysis was done to obtain parameter uncertainties and correlations. The resulting UNEDF2 is an all-around EDF. However, the sensitivity analysis also demonstrated that the limits of current Skyrme-like EDFs have been reached and that novel approaches are called for.

Kortelainen, M; Nazarewicz, W; Olsen, E; Reinhard, P -G; Sarich, J; Schunck, N; Wild, S M; Davesne, D; Erler, J; Pastore, A

2014-01-01T23:59:59.000Z

376

Nuclear Energy Density Optimization: UNEDF2  

E-Print Network (OSTI)

The parameters of the UNEDF2 nuclear energy density functional (EDF) model were obtained in an optimization to experimental data consisting of nuclear binding energies, proton radii, odd-even mass staggering data, fission-isomer excitation energies, and single particle energies. In addition to parameter optimization, sensitivity analysis was done to obtain parameter uncertainties and correlations. The resulting UNEDF2 is an all-around EDF. However, the sensitivity analysis also demonstrated that the limits of current Skyrme-like EDFs have been reached and that novel approaches are called for.

M. Kortelainen; J. McDonnell; W. Nazarewicz; E. Olsen; P. -G. Reinhard; J. Sarich; N. Schunck; S. M. Wild; D. Davesne; J. Erler; A. Pastore

2014-10-30T23:59:59.000Z

377

Calculation of 239Pu fission observables in an event-by-event simulation  

SciTech Connect

The increased interest in more exclusive fission observables has demanded more detailed models. We describe a new computational model, FREYA, that aims to meet this need by producing large samples of complete fission events from which any observable of interest can then be extracted consistently, including any interesting correlations. The various model assumptions are described and the potential utility of the model is illustrated. As a concrete example, we use formal statistical methods, experimental data on neutron production in neutron-induced fission of {sup 239}Pu, along with FREYA, to develop quantitative insights into the relation between reaction observables and detailed microscopic aspects of fission. Current measurements of the mean number of prompt neutrons emitted in fission taken together with less accurate current measurements for the prompt post-fission neutron energy spectrum, up to the threshold for multi-chance fission, place remarkably fine constraints on microscopic theories.

Vogt, R; Randrup, J; Pruet, J; Younes, W

2010-03-31T23:59:59.000Z

378

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

DOE Patents (OSTI)

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

Herrmann, Steven Douglas

2014-05-27T23:59:59.000Z

379

Quantum reservoirs with ion chains  

E-Print Network (OSTI)

Ion chains are promising platforms for studying and simulating quantum reservoirs. One interesting feature is that their vibrational modes can mediate entanglement between two objects which are coupled through the vibrational modes of the chain. In this work we analyse entanglement between the transverse vibrations of two heavy impurity defects embedded in an ion chain, which is generated by the coupling with the chain vibrations. We verify general scaling properties of the defects dynamics and demonstrate that entanglement between the defects can be a stationary feature of these dynamics. We then analyse entanglement in chains composed of tens of ions and propose a measurement scheme which allows one to verify the existence of the predicted entangled state.

B. G. Taketani; T. Fogarty; E. Kajari; Th. Busch; Giovanna Morigi

2014-02-06T23:59:59.000Z

380

The Radiation Safety Information Computational Center (RSICC): A Resource for Nuclear Science Applications  

SciTech Connect

The Radiation Safety Information Computational Center (RSICC) has been in existence since 1963. RSICC collects, organizes, evaluates and disseminates technical information (software and nuclear data) involving the transport of neutral and charged particle radiation, and shielding and protection from the radiation associated with: nuclear weapons and materials, fission and fusion reactors, outer space, accelerators, medical facilities, and nuclear waste management. RSICC serves over 12,000 scientists and engineers from about 100 countries.

Kirk, Bernadette Lugue [ORNL] [ORNL

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "nuclear fission chain" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Deep Atomic Binding (DAB) Hypothesis: A New Approach of Fission Product Chemistry  

SciTech Connect

Former studies assumed that, after fission process occurs, the highly ionized new born atoms (20-22 positive charge), ionize the media in which they pass through before becoming stable atoms in a manner similar to 4-MeV ?-particles. Via ordinary chemical reactions with the surroundings, each stable atom has a probability to form chemical compound. Since there are about 35 different elemental atoms created through fission processes, a large number of chemical species were suggested to be formed. But, these suggested chemical species were not found in the environment after actual releases of FP during accidents like TMI (USA, 1979), and Chernobyl (former USSR, 1986), also the models based on these suggested reactions and species could not interpret the behavior of these actual species. It is assumed here that the ionization states of the new born atoms and the long term high temperature were not dealt with in an appropriate way and they were the reasons of former models failure. Our new approach of Deep Atomic Binding (DAB) based on the following: 1-The new born atoms which are highly ionized, 10-12 electrons associated with each nucleus, having a large probability to create bonds between them to form molecules. These bonds are at the L, or M shells, and we call it DAB. 2-The molecules stay in the reactor at high temperatures for long periods, so they undergo many stages of composition and decomposition to form giant molecules. By applying DAB approach, field data from Chernobyl, TMI and nuclear detonations could be interpreted with a wide coincidence resulted. (author)

Ajlouni, Abdul-Wali M.S. [Ministry of Energy and Mineral Resources (Jordan)

2006-07-01T23:59:59.000Z

382

Florencite-(La) with fissiogenic REEs from a natural fission reactor at Bangombe, Gabon  

SciTech Connect

Florecite-(La) (La/Ce = 1.09) with fissiogenic REEs and florecite-(Ce) (La/Ce = 0.62) have been identified in illite from the clay mantle surrounding a natural, 2 Ga fission reactor at Bangombre and in sandstone beneath the reactor zone, respectively. Florencite-(Ce) is apparently unrelated to nuclear processes and occurs with monazite-(Ce), apatite, TiO{sub 2} (probably anatase), zircon, and illite. Grains of florencite-(Ce) contain inclusions of thorite, chalcopyrite, and galena. Florencite-(La) was found 5 cm from the {open_quotes}core{close_quotes} of the reactor and contains inclusions of galena and U-Ti-bearing phases. Secondary uraninite and coffinite have precipitated on some of the florencite grains. The chemical composition of florencite-(La) as determined by electron microprobe analysis is (La{sub 0.38}Ce{sub 0.35}Nd{sub 0.06}Sm{sub 0.01}-Ca{sub 0.03}Sr{sub 0.17})(Al{sub 2.98}Fe{sub 0.02}{sup 3+})(PO{sub 4})[PO{sub 3.80}(OH){sub 0.20}](OH){sub 6}. Secondary ion mass spectrometry revealed that between 27 and 30% of Nd and 67 and 71% of Sm in florencite-(La) is fissiogenic. The presence of fissiogenic REEs in {open_quotes}florencite{close_quotes} from the reactor zone in Bangombe and their preferential concentration in florencite relative to the bulk sample of clay demonstrate that aluminous phosphates may have played a more significant role in the fixation of fissiogenic REES released from uraninite after the sustained fission reactions than sorption onto clays. 30 refs., 3 figs., 2 tabs.

Janeczek, J. [Univ. of Silesia, Sosnowiec (Poland); Ewing, R.C. [Univ. of New Mexico, Albuquerque, NM (United States)

1996-09-01T23:59:59.000Z

383

Fusion-Fission Hybrid for Fissile Fuel Production without Processing  

SciTech Connect

Two scenarios are typically envisioned for thorium fuel cycles: 'open' cycles based on irradiation of {sup 232}Th and fission of {sup 233}U in situ without reprocessing or 'closed' cycles based on irradiation of {sup 232}Th followed by reprocessing, and recycling of {sup 233}U either in situ or in critical fission reactors. This study evaluates a third option based on the possibility of breeding fissile material in a fusion-fission hybrid reactor and burning the same fuel in a critical reactor without any reprocessing or reconditioning. This fuel cycle requires the hybrid and the critical reactor to use the same fuel form. TRISO particles embedded in carbon pebbles were selected as the preferred form of fuel and an inertial laser fusion system featuring a subcritical blanket was combined with critical pebble bed reactors, either gas-cooled or liquid-salt-cooled. The hybrid reactor was modeled based on the earlier, hybrid version of the LLNL Laser Inertial Fusion Energy (LIFE1) system, whereas the critical reactors were modeled according to the Pebble Bed Modular Reactor (PBMR) and the Pebble Bed Advanced High Temperature Reactor (PB-AHTR) design. An extensive neutronic analysis was carried out for both the hybrid and the fission reactors in order to track the fuel composition at each stage of the fuel cycle and ultimately determine the plant support ratio, which has been defined as the ratio between the thermal power generated in fission reactors and the fusion power required to breed the fissile fuel burnt in these fission reactors. It was found that the maximum attainable plant support ratio for a thorium fuel cycle that employs neither enrichment nor reprocessing is about 2. This requires tuning the neutron energy towards high energy for breeding and towards thermal energy for burning. A high fuel loading in the pebbles allows a faster spectrum in the hybrid blanket; mixing dummy carbon pebbles with fuel pebbles enables a softer spectrum in the critical reactors. This combination consumes about 20% of the thorium initially loaded in the hybrid reactor ({approx}200 GWd/tHM), partially during hybrid operation, but mostly during operation in the critical reactor. The plant support ratio is low compared to the one attainable using continuous fuel chemical reprocessing, which can yield a plant support ratio of about 20, but the resulting fuel cycle offers better proliferation resistance as fissile material is never separated from the other fuel components.

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

2012-01-02T23:59:59.000Z

384

Nuclear Data Sheets for A = 206  

Science Journals Connector (OSTI)

Evaluated nuclear structure and decay data for all nuclei within the A = 206 mass chain are presented. The experimental data are evaluated and recommended best values for level and gamma-ray energies, quantum numbers, lifetimes, gamma-ray intensities and other nuclear properties are presented. Inconsistencies and discrepancies that exist in the literature are noted. This work supersedes the earlier evaluation by E. Browne (1999Br39), published in Nuclear Data Sheets 88, 29 (1999).

F.G. Kondev

2008-01-01T23:59:59.000Z

385

Nuclear Resonance Fluorescence for Nuclear Materials Assay  

E-Print Network (OSTI)

Potential of Nuclear Resonance Fluorescence . . . . . . . .2.9.1 Nuclear ThomsonSections . . . . . . . . . . . . . . . Nuclear Resonance

Quiter, Brian Joseph

2010-01-01T23:59:59.000Z

386

Method of fission heat flux determination from experimental data  

DOE Patents (OSTI)

A method is provided for determining the fission heat flux of a prime specimen inserted into a specimen of a test reactor. A pair of thermocouple test specimens are positioned at the same level in the holder and a determination is made of various experimental data including the temperature of the thermocouple test specimens, the temperature of bulk water channels located in the test holder, the gamma scan count ratios for the thermocouple test specimens and the prime specimen, and the thicknesses of the outer clads, the fuel fillers, and the backclad of the thermocouple test specimen. Using this experimental data, the absolute value of the fission heat flux for the thermocouple test specimens and prime specimen can be calculated.

Paxton, Frank A. (Schenectady, NY)

1999-01-01T23:59:59.000Z

387

Manhattan Project: The Discovery of Fission, 1938-1939  

Office of Scientific and Technical Information (OSTI)

Lise Meitner and Otto Hahn, Kaiser-Wilhelm Institute, Berlin THE DISCOVERY OF FISSION Berlin, Germany (1938-1939) Events > Atomic Discoveries, 1890s-1939 A Miniature Solar System, 1890s-1919 Exploring the Atom, 1919-1932 Atomic Bombardment, 1932-1938 The Discovery of Fission, 1938-1939 Fission Comes to America, 1939 The English word "atom" derives from the Greek word "atomon" ("ατομον"), which means "that which cannot be divided." In 1938, the scientific community proved the Greek philosophers wrong by dividing the atom. Excerpt from the comic book "Adventures Inside the Atom." Click on this image or visit the "Library" to view the whole comic book. Fission, the basis of the atomic bomb, was discovered in Nazi Germany less than a year before the beginning of the Second World War. It was December 1938 when the radiochemists Otto Hahn (above, with Lise Meitner) and Fritz Strassmann, while bombarding elements with neutrons in their Berlin laboratory, made their unexpected discovery. They found that while the nuclei of most elements changed somewhat during neutron bombardment, uranium nuclei changed greatly and broke into two roughly equal pieces. They split and became not the new transuranic elements that some thought Enrico Fermi had discovered but radioactive barium isotopes (barium has the atomic number 56) and other fragments of the uranium itself. The substances Fermi had created in his experiments, that is, did more than resemble lighter elements -- they were lighter elements. The products of the Hahn-Strassmann experiment weighed less than that of the original uranium nucleus, and herein lay the primary significance of their findings. It folIowed from Albert Einstein's E=mc2 equation that the loss of mass resulting from the splitting process must have been converted into energy in the form of kinetic energy that could in turn be converted into heat.

388

Nuclear energy | Princeton Plasma Physics Lab  

NLE Websites -- All DOE Office Websites (Extended Search)

Nuclear energy Nuclear energy Subscribe to RSS - Nuclear energy Energy that originates from the splitting of uranium atoms in a process called fission. This is distinct from a process called fusion where energy is released when atomic nuclei combine or fuse. Two PPPL-led teams win increased supercomputing time to study conditions inside fusion plasmas Researchers led by scientists at the U.S. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL) have won highly competitive allocations of time on two of the world's fastest supercomputers. The increased awards are designed to advance the development of nuclear fusion as a clean and abundant source of energy for generating electricity. Read more about Two PPPL-led teams win increased supercomputing time

389

Argonne explains nuclear recycling in 4 minutes  

SciTech Connect

Currently, when using nuclear energy only about five percent of the uranium used in a fuel rod gets fissioned for energy; after that, the rods are taken out of the reactor and put into permanent storage. There is a way, however, to use almost all of the uranium in a fuel rod. Recycling used nuclear fuel could produce hundreds of years of energy from just the uranium we've already mined, all of it carbon-free. Problems with older technology put a halt to recycling used nuclear fuel in the United States, but new techniques developed by scientists at Argonne National Laboratory address many of those issues. For more information, visit http://www.anl.gov/energy/nuclear-energy.

None

2012-01-01T23:59:59.000Z

390

Chapter 6 - Nuclear-Powered Payload Safety  

Science Journals Connector (OSTI)

Abstract This chapter introduces the concepts of Space Nuclear Power Systems (SNPSs), describes the history and nature of these ingenious energy-generating machines. The basic principles of the Radioisotope Thermoelectric Generator (RTG) and the recently developed Stirling Radioisotope Generator (SRG) are explored and an account of their application in several extra-terrestrial missions is presented. Nuclear fission power as a promising alternative for future outer planet and extra-solar explorations is discussed. The flight safety review and launch approval processes for U.S., as well as the failures and accidents for U.S. and U.S.S.R. (Russian) nuclear powered space missions since 1961 are presented chronologically. A comprehensive probabilistic consequence analysis of all conceivable potential hazards associated with nuclear powered space flights is set out. The chapter concludes with how \\{SNPSs\\} must be designed with the built-in safety features to minimize accidents and to prevent radiation exposure.

Firooz A. Allahdadi; Sayavur I. Bakhtiyarov; Gregory D. Wyss; Gary F. Polansky; Joseph A. Sholtis; Curt D. Botts

2013-01-01T23:59:59.000Z

391

Argonne explains nuclear recycling in 4 minutes  

ScienceCinema (OSTI)

Currently, when using nuclear energy only about five percent of the uranium used in a fuel rod gets fissioned for energy; after that, the rods are taken out of the reactor and put into permanent storage. There is a way, however, to use almost all of the uranium in a fuel rod. Recycling used nuclear fuel could produce hundreds of years of energy from just the uranium we've already mined, all of it carbon-free. Problems with older technology put a halt to recycling used nuclear fuel in the United States, but new techniques developed by scientists at Argonne National Laboratory address many of those issues. For more information, visit http://www.anl.gov/energy/nuclear-energy.

None

2013-04-19T23:59:59.000Z

392

Materials Challenges in Nuclear Energy  

SciTech Connect

Nuclear power currently provides about 13% of the worldwide electrical power, and has emerged as a reliable baseload source of electricity. A number of materials challenges must be successfully resolved for nuclear energy to continue to make further improvements in reliability, safety and economics. The operating environment for materials in current and proposed future nuclear energy systems is summarized, along with a description of materials used for the main operating components. Materials challenges associated with power uprates and extensions of the operating lifetimes of reactors are described. The three major materials challenges for the current and next generation of water-cooled fission reactors are centered on two structural materials aging degradation issues (corrosion and stress corrosion cracking of structural materials and neutron-induced embrittlement of reactor pressure vessels), along with improved fuel system reliability and accident tolerance issues. The major corrosion and stress corrosion cracking degradation mechanisms for light water reactors are reviewed. The materials degradation issues for the Zr alloy clad UO2 fuel system currently utilized in the majority of commercial nuclear power plants is discussed for normal and off-normal operating conditions. Looking to proposed future (Generation IV) fission and fusion energy systems, there are 5 key bulk radiation degradation effects (low temperature radiation hardening and embrittlement, radiation-induced and modified solute segregation and phase stability, irradiation creep, void swelling, and high temperature helium embrittlement) and a multitude of corrosion and stress corrosion cracking effects (including irradiation-assisted phenomena) that can have a major impact on the performance of structural materials.

Zinkle, Steven J [ORNL] [ORNL; Was, Gary [University of Michigan] [University of Michigan

2013-01-01T23:59:59.000Z

393

(Fission product transport experiments (HFR-B1))  

SciTech Connect

Travel to the JRC Petten was for the purpose of discussing the HFR-B1 experiment and post irradiation activities. Technical assessment of the experiment strongly supports the concept of enhanced fission gas release at temperatures above 1100{degree}C, the extensive release of stored fission gas at water vapor levels postulated in accident scenarios, an increase in the steady-state fission gas release under hydrolyzing conditions, and an increase in gas release during thermal cycling. Schedules were established for completion of the work and issuance of reports by September 1990. At the KFA Juelich agreement was reached on the PIE activities for HFR-B1 and a schedule established. The final PIE report is due June 1991. Choices of accident condition tests in the PIE have yet to be made by the US participants. A proposal for the establishment of a new cooperative effort on model and code development was presented at the Institut fuer Nukleare Sicherheitsforschung of KFA. The proposal was considered premature; discussions dealing with general principles, basic aims, and organization were requested; particular concerns about free exchange of information, overlap with the existing safety subprogram, and exclusive cooperation with ORNL were raised. A strong desire for cooperation and the opinion that the raised problems could be resolved were expressed. Technical discussions at the KFA were beneficial.

Myers, B.F.

1989-12-05T23:59:59.000Z

394

Internet-Enabled Supply ChainsInternet-Enabled Supply Chains Quan Z. Sheng, University of Adelaide  

E-Print Network (OSTI)

89 Internet-Enabled Supply ChainsInternet-Enabled Supply Chains Quan Z. Sheng, University of the Internet-enabled Supply Chain 89 Key Supply Chain Processes and the Internet 89 Impacts of Internet-Enabled Supply Chains 92 Enabling Technologies for Internet-Enabled Supply Chain Management 92 Internet-based EDI

Sheng, Michael

395

Nuclear Returns  

Science Journals Connector (OSTI)

Nuclear Returns ... For the first time since 1978, the Nuclear Regulatory Commission has given the green light for a new U.S. nuclear power plant. ... NRC granted a license to Southern Co. to build and operate twin 1,100-MW reactors adjacent to two operating nuclear power plants at its Vogtle nuclear facility, near Waynesboro, Ga. ...

JEFF JOHNSON

2012-02-19T23:59:59.000Z

396

Extracorporeal membrane oxygenation promotes long chain fatty...  

NLE Websites -- All DOE Office Websites (Extended Search)

membrane oxygenation promotes long chain fatty acid oxidation in the immature swine heart in vivo. Extracorporeal membrane oxygenation promotes long chain fatty acid oxidation...

397

Advanced Monte Carlo modeling of prompt fission neutrons for thermal and fast neutron-induced fission reactions on Pu239  

Science Journals Connector (OSTI)

Prompt fission neutrons following the thermal and 0.5 MeV neutron-induced fission reaction of Pu239 are calculated using a Monte Carlo approach to the evaporation of the excited fission fragments. Exclusive data such as the multiplicity distribution P(?), the average multiplicity as a function of fragment mass ??(A), and many others are inferred in addition to the most used average prompt fission neutron spectrum ?(Ein,Eout), as well as average neutron multiplicity ??. Experimental information on these more exclusive data help constrain the Monte Carlo model parameters. The calculated average total neutron multiplicity is ??c=2.871 in very close agreement with the evaluated value ??e=2.8725 present in the ENDF/B-VII.0 library. The neutron multiplicity distribution P(?) is in very good agreement with the evaluation by Holden and Zucker. The calculated average spectrum differs in shape from the ENDF/B-VII.0 spectrum, evaluated with the Madland-Nix model. In particular, we predict more neutrons in the low-energy tail of the spectrum (below about 300 keV) than the Madland-Nix calculations, casting some doubts on how much scission neutrons contribute to the shape of the low-energy tail of the spectrum. The spectrum high-energy tail is very sensitive to the total kinetic energy distribution of the fragments as well as to the total excitation energy sharing at scission. Present experimental uncertainties on measured spectra above 6 MeV are too large to distinguish between various theoretical hypotheses. Finally, comparisons of the Monte Carlo results with experimental data on ??(A) indicate that more neutrons are emitted from the light fragments than the heavy ones, in agreement with previous works.

P. Talou; B. Becker; T. Kawano; M. B. Chadwick; Y. Danon

2011-06-23T23:59:59.000Z

398

Total supply chain cost model  

E-Print Network (OSTI)

Sourcing and outsourcing decisions have taken on increased importance within Teradyne to improve efficiency and competitiveness. This project delivered a conceptual framework and a software tool to analyze supply chain ...

Wu, Claudia

2005-01-01T23:59:59.000Z

399

Microstructural Characterization of Irradiated U-7Mo/Al-5Si Dispersion to High Fission Density  

SciTech Connect

The fuel development program for research and test reactors calls for improved knowledge on the effect of microstructure on fuel performance in reactors. This work summarizes the recent TEM microstructural characterization of an irradiated U-7Mo/Al-5Si dispersion fuel plate (R3R050) irradiated in the Advanced Test Reactor (ATR) at Idaho National Laboratory to 5.2×1021 fissions/cm3. While a large fraction of the fuel grains is decorated with large bubbles, there is no evidence showing interlinking of these large bubbles at the specified fission density. The attachment of solid fission product precipitates to the bubbles is likely the result of fission product diffusion into these bubbles. The process of fission gas bubble superlattice collapse appears through bubble coalescence. The results are compared with the previous TEM work of the dispersion fuels irradiated to lower fission density from the same fuel plate.

J. Gan; B. D. Miller; D. D. Keiser, Jr.; A. B. Robinson; J. W. Madden; P. G. Medvedev; D. M. Wachs

2014-11-01T23:59:59.000Z

400

Experimental Measurements of Short-Lived Fission Products from Uranium, Neptunium, Plutonium and Americium  

SciTech Connect

Fission yields are especially well characterized for long-lived fission products. Modeling techniques incorporate numerous assumptions and can be used to deduce information about the distribution of short-lived fission products. This work is an attempt to gather experimental (model-independent) data on the short-lived fission products. Fissile isotopes of uranium, neptunium, plutonium and americium were irradiated under pulse conditions at the Washington State University 1 MW TRIGA reactor to achieve ~108 fissions. The samples were placed on a HPGe (high purity germanium) detector to begin counting in less than 3 minutes post irradiation. The samples were counted for various time intervals ranging from 5 minutes to 1 hour. The data was then analyzed to determine which radionuclides could be quantified and compared to the published fission yield data.

Metz, Lori A.; Payne, Rosara F.; Friese, Judah I.; Greenwood, Lawrence R.; Kephart, Jeremy D.; Pierson, Bruce D.

2009-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "nuclear fission chain" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Nuclear Fusion  

Science Journals Connector (OSTI)

Although not yet developed at the commercial stage, nuclear fusion technology is still being considered as a ... used in nuclear warfare. Since research in nuclear fusion for the production of energy started abou...

Ricardo Guerrero-Lemus; José Manuel Martínez-Duart

2013-01-01T23:59:59.000Z

402

Nuclear Nonproliferation  

NLE Websites -- All DOE Office Websites (Extended Search)

Nuclear Nonproliferation As more countries embrace nuclear power as a cost-effective and clean alternative to fossil fuels, the need exists to ensure that the nuclear fuel cycle is...

403

Dynamic Systems Analysis Report for Nuclear Fuel Recycle  

SciTech Connect

This report examines the time-dependent dynamics of transitioning from the current United States (U.S.) nuclear fuel cycle where used nuclear fuel is disposed in a repository to a closed fuel cycle where the used fuel is recycled and only fission products and waste are disposed. The report is intended to help inform policy developers, decision makers, and program managers of system-level options and constraints as they guide the formulation and implementation of advanced fuel cycle development and demonstration efforts and move toward deployment of nuclear fuel recycling infrastructure.

Brent Dixon; Sonny Kim; David Shropshire; Steven Piet; Gretchen Matthern; Bill Halsey

2008-12-01T23:59:59.000Z

404

Nuclear Engineering Nuclear Criticality Safety  

E-Print Network (OSTI)

Nuclear Engineering Nuclear Criticality Safety The Nuclear Engineering Division (NE) of Argonne National Laboratory is experienced in performing criticality safety and shielding evaluations for nuclear, and neutron spectra. The NE nuclear criticality safety (NCS) capabilities are based on a staff with decades

Kemner, Ken

405

Antineutrino spectra from 241Pu and 239Pu thermal neutron fission products  

Science Journals Connector (OSTI)

The antineutrino spectrum of fission products from thermal neutron induced fission of 241Pu was derived from a measurement of the correlated beta spectrum. The energy range 1.5 MeV to 9 MeV was covered and a precision of 4% was achieved at 4 MeV. A revised version of the antineutrino spectrum from 239Pu fission is also presented.

A.A. Hahn; K. Schreckenbach; W. Gelletly; F. von Feilitzsch; G. Colvin; B. Krusche

1989-01-01T23:59:59.000Z

406

Nuclear Energy  

NLE Websites -- All DOE Office Websites (Extended Search)

Nuclear Energy Idaho National Laboratory is the Department of Energy's lead nuclear energy research and development facility. Building upon its legacy responsibilities,...

407

Nuclear Hydrogen  

NLE Websites -- All DOE Office Websites (Extended Search)

Error Error Nuclear Hydrogen - RCC cannot be displayed due to a timeout error. We recommend: * Refresh Nuclear Hydrogen - RCC * Increasing your portlet timeout setting. *...

408

Nuclear Physics  

NLE Websites -- All DOE Office Websites (Extended Search)

Underground Research Facility in South Dakota, which will search for neutrinoless double-beta decay. Strong Los Alamos programs in nuclear data and nuclear theory supports...

409

Impact of Fission Products Impurity on the Plutonium Content of Metal- and Oxide- Fuels in Sodium Cooled Fast Reactors  

SciTech Connect

This short report presents the neutronic analysis to evaluate the impact of fission product impurity on the Pu content of Sodium-cooled Fast Reactor (SFR) metal- and oxide- fuel fabrication. The similar work has been previously done for PWR MOX fuel [1]. The analysis will be performed based on the assumption that the separation of the fission products (FP) during the reprocessing of UOX spent nuclear fuel assemblies is not perfect and that, consequently, a certain amount of FP goes into the Pu stream used to fabricate SFR fuels. Only non-gaseous FPs have been considered (see the list of 176 isotopes considered in the calculations in Appendix 1 of Reference 1). Throughout of this report, we define the mixture of Pu and FPs as PuFP. The main objective of this analysis is to quantify the increase of the Pu content of SFR fuels necessary to maintain the same average burnup at discharge independently of the amount of FP in the Pu stream, i.e. independently of the PuFP composition. The FP losses are considered element-independent, i.e., for example, 1% of FP losses mean that 1% of all non-gaseous FP leak into the Pu stream.

Hikaru Hiruta; Gilles Youinou

2013-09-01T23:59:59.000Z

410

E-Print Network 3.0 - alpha -particle fission Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

thermal history Summary: -feldspar ages (214 Ma) from the Jiazishan syenites. A titanite fission-track age of 166 8 Ma (closure... cooling and reheating event is indicated...

411

The Future of University Nuclear Engineering Programs and University  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

The Future of University Nuclear Engineering Programs and The Future of University Nuclear Engineering Programs and University Research and Training Reactors The Future of University Nuclear Engineering Programs and University Research and Training Reactors Nuclear engineering programs and departments with an initial emphasis in fission were formed in the late 1950's and 1960's from interdisciplinary efforts in many of the top research universities, providing the manpower for this technical discipline. In the same time period, for many of these programs, university nuclear reactors were constructed and began their operation, providing some of the facilities needed for research and training of students engaged in this profession. However, over the last decade, the U.S. nuclear science and engineering educational structure has not only stagnated but has reached a state of

412

The Future of University Nuclear Engineering Programs and University  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

The Future of University Nuclear Engineering Programs and The Future of University Nuclear Engineering Programs and University Research and Training Reactors The Future of University Nuclear Engineering Programs and University Research and Training Reactors Nuclear engineering programs and departments with an initial emphasis in fission were formed in the late 1950's and 1960's from interdisciplinary efforts in many of the top research universities, providing the manpower for this technical discipline. In the same time period, for many of these programs, university nuclear reactors were constructed and began their operation, providing some of the facilities needed for research and training of students engaged in this profession. However, over the last decade, the U.S. nuclear science and engineering educational structure has not only stagnated but has reached a state of

413

Nuclear Matter and Nuclear Dynamics  

E-Print Network (OSTI)

Highlights on the recent research activity, carried out by the Italian Community involved in the "Nuclear Matter and Nuclear Dynamics" field, will be presented.

M Colonna

2009-02-26T23:59:59.000Z

414

New calculation for the neutron-induced fission cross section of Pa233 between 1.0 and 3.0MeV  

Science Journals Connector (OSTI)

The Pa233(n,f) cross section, a key ingredient for fast reactors and accelerators driven systems, was measured recently with relatively good accuracy [F. Tovesson et al., Phys. Rev. Lett. 88, 062502 (2002)]. The results are at strong variance with accepted evaluations and an existing indirect experiment. This circumstance led us to perform a quite detailed and complete evaluation of the Pa233(n,f) cross section between 1.0 and 3.0MeV, where use of our newly developed routines for the parametrization of the nuclear surface and the calculation of deformation parameters and level densities (including low-energy discrete levels) were made. The results show good quantitative and excellent qualitative agreement with the experimental direct data obtained by Tovesson et al. [F. Tovesson et al., Phys. Rev. Lett. 88, 062502 (2002)]. Additionally, our methodology opens new possibilities for the analysis of subthreshold fission and above threshold second-chance fission for both Pa233 and its decay product U233, as well as other strategically important fissionable nuclides.

J. Mesa; J. D. T. Arruda-Neto; A. Deppman; V. P. Likhachev; M. V. Manso; C. E. Garcia; O. Rodriguez; F. Guzmán; F. Garcia

2003-11-20T23:59:59.000Z

415

Analysis of Fission Products on the AGR-1 Capsule Components  

SciTech Connect

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

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

2013-03-01T23:59:59.000Z

416

Sustainable Supply Chain | Data.gov  

NLE Websites -- All DOE Office Websites (Extended Search)

Sustainable Supply Chain Sustainable Supply Chain Sustainable Supply Chains Submissions Let's Talk About Sustainable Supply Chain Welcome to the Sustainable Supply Chain Community of Practice Bringing together government, industry, associations, non-profits and academic institutions to achieve more sustainable supply chains. Sustainable Supply Chain - New Updates New Updates View More Be a Champion Be a champion The Sustainable Supply Chain Community of Practice seeks champions from industry, academia and non-profits to lead each of the community market sectors. Do you know or are you a member of a leading edge organization that is implementing sustainable supply chain practices within one of the seven current community market sectors? If yes, nominate the organization as a Champion. Sustainable supply chain practices lead to cost savings,

417

Working Party on International Nuclear Data Evaluation Cooperation (WPEC)  

SciTech Connect

The OECD Nuclear Energy Agency (NEA) is organizing the cooperation between the major nuclear data evaluation projects in the world. The NEA Working Party on International Nuclear Data Evaluation Cooperation (WPEC) was established to promote the exchange of information on nuclear data evaluation, measurement, nuclear model calculation, validation, and related topics, and to provide a framework for cooperative activities between the participating projects. The working party assesses nuclear data improvement needs and addresses these needs by initiating joint activities in the framework of dedicated WPEC subgroups. Studies recently completed comprise a number of works related to nuclear data covariance and associated processing issues, as well as more specific studies related to the resonance parameter representation in the unresolved resonance region, the gamma production from fission-product capture reactions, the U-235 capture cross-section, the EXFOR database, and the improvement of nuclear data for advanced reactor systems. Ongoing activities focus on the evaluation of Pu-239 in the resonance region, scattering angular distribution in the fast energy range, and reporting/usage of experimental data for evaluation in the resolved resonance region. New activities include two new subgroups on improved fission product yield evaluation methodologies and on modern nuclear database structures. Future activities under discussion include a pilot project of a Collaborative International Evaluated Library (CIELO) and methods to provide feedback from nuclear and covariance data adjustment for improvement of nuclear data. In addition to the above mentioned short-term, task-oriented subgroups, the WPEC also hosts a longer-term subgroup charged with reviewing and compiling the most important nuclear data requirements in a high priority request list (HPRL).

Giuseppe Palmiotti

2014-06-01T23:59:59.000Z

418

Working Party on International Nuclear Data Evaluation Cooperation (WPEC)  

Science Journals Connector (OSTI)

Abstract The OECD Nuclear Energy Agency (NEA) organizes cooperation between the major nuclear data evaluation projects in the world. The NEA Working Party on International Nuclear Data Evaluation Cooperation (WPEC) was established to promote the exchange of information on nuclear data evaluation, measurement, nuclear model calculation, validation, and related topics, and to provide a framework for cooperative activities between the participating projects. The working party assesses nuclear data improvement needs and addresses these needs by initiating joint activities in the framework of dedicated WPEC subgroups. Studies recently completed comprise a number of works related to nuclear data covariance and associated processing issues, as well as more specific studies related to the resonance parameter representation in the unresolved resonance region, the gamma production from fission product capture reactions, the 235U capture cross section, the EXFOR database, and the improvement of nuclear data for advanced reactor systems. Ongoing activities focus on the evaluation of 239Pu in the resonance region, scattering angular distribution in the fast energy range, and reporting/usage of experimental data for evaluation in the resolved resonance region. New activities include two subgroups on improved fission product yield evaluation methodologies and on modern nuclear database structures. Future activities under discussion include a pilot project for a Collaborative International Evaluated Library Organization (CIELO) and methods to provide feedback from nuclear and covariance data adjustment for improvement of nuclear data. In addition to the above mentioned short-term task-oriented subgroups, WPEC also hosts a longer-term subgroup charged with reviewing and compiling the most important nuclear data requirements in a high priority request list (HPRL).

E. Dupont; M.B. Chadwick; Y. Danon; C. De Saint Jean; M. Dunn; U. Fischer; R.A. Forrest; T. Fukahori; Z. Ge; H. Harada; M. Herman; M. Igashira; A. Ignatyuk; M. Ishikawa; O. Iwamoto; R. Jacqmin; A.C. Kahler; T. Kawano; A.J. Koning; L. Leal; Y.O. Lee; R. McKnight; D. McNabb; R.W. Mills; G. Palmiotti; A. Plompen; M. Salvatores; P. Schillebeeckx

2014-01-01T23:59:59.000Z

419

Energy Spectrum of Neutrons from Thermal Fission of U235  

Science Journals Connector (OSTI)

A proton recoil counter has been used to determine the neutron spectrum, in the energy range 3.3-17 Mev, of a beam produced by irradiating 95 percent U235 (metal) in the central experimental hole of the Los Alamos Homogeneous Reactor. Most of the fissions were induced by slow neutrons. The data are combined with those obtained by D. Hill and by T. W. Bonner, R. A. Ferrell and M. C. Rinehart; the composite spectrum so obtained extends from 0.075 to 17 Mev. Fits with two general formulas are discussed.

B. E. Watt

1952-09-15T23:59:59.000Z

420

Fission meter and neutron detection using poisson distribution comparison  

DOE Patents (OSTI)

A neutron detector system and method for discriminating fissile material from non-fissile material wherein a digital data acquisition unit collects data at high rate, and in real-time processes large volumes of data directly into information that a first responder can use to discriminate materials. The system comprises counting neutrons from the unknown source and detecting excess grouped neutrons to identify fission in the unknown source. Comparison of the observed neutron count distribution with a Poisson distribution is performed to distinguish fissile material from non-fissile material.

Rowland, Mark S; Snyderman, Neal J

2014-11-18T23:59:59.000Z

Note: This page contains sample records for the topic "nuclear fission chain" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Population of superdeformed bands and competition with fission  

SciTech Connect

Average entry points for superdeformed (SD) and normal states have been measured in {sup 191, 192}Hg and in {sup 152}Dy. Compared with normal states, the superdeformed states have entry spins {approximately} 10 h higher and internal excitation energies (U = E --- E{sub yrast}) at least 2 MeV lower for the Hg cases and about 8 MeV lower for {sup 152}Dy. By comparison with calculated {ell}- distributions of evaporation residues (ER), using CASCADE to compute the fission competition, we find that the initial population of the SD band in {sup 192}Hg originates from the tail of the ER spin distribution. 12 refs., 5 figs.

Moore, E.F.; Janssens, R.V.F.; Khoo, T.L.; Ahmad, I.; Carpenter, M.P.; Chasman, R.R.; Wolfs, F.L.H. (Argonne National Lab., IL (USA)); Beard, K.B; Garg, U.; Ye, D. (Notre Dame Univ., IN (USA)); Benet, Ph.; Daly, P.J.; Grabowski, Z.W. (Purdue Univ., Lafayette, IN (USA)); Drigert, M.W. (Idaho National Engineering Lab., Idaho Falls, ID (USA))

1990-01-01T23:59:59.000Z

422

Prompt {gamma}-ray spectroscopy of isotopically identified fission fragments  

SciTech Connect

Measurements of prompt Doppler-corrected deexcitation {gamma} rays from uniquely identified fragments formed in fusion-fission reactions of the type {sup 12}C({sup 238}U,{sup 134}Xe)Ru are reported. The fragments were identified in both A and Z using the variable-mode, high-acceptance magnetic spectrometer VAMOS. States built on the characteristic neutron configurations forming high-spin isomers (7{sup -} and 10{sup +}) in {sup 134}Xe are presented and compared with the predictions of shell-model calculations using a new effective interaction in the region of Z{>=}50 and N{<=}82.

Shrivastava, A.; Caamano, M.; Rejmund, M.; Navin, A.; Rejmund, F.; Lemasson, A.; Schmitt, C.; Derkx, X.; Fernandez-Dominguez, B.; Golabek, C.; Roger, T. [GANIL, CEA/DSM--CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5 (France); Schmidt, K.-H. [GANIL, CEA/DSM-CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5 (France) and GSI-Helmholtzzentrum fuer Schwerionenforschung mbH, Planckstrasse 1, D-64220 Darmstadt (Germany); Gaudefroy, L.; Taieb, J. [CEA, DAM, DIF, F-91297 Arpajon (France); Sieja, K. [GSI-Helmholtzzentrum fuer Schwerionenforschung mbH, Planckstrasse 1, D-64220 Darmstadt (Germany); Institut fuer Kernphysik, Technische Universitaet Darmstadt, D-64289 Darmstadt (Germany); Audouin, L.; Bacri, C. O. [Institut de Physique Nucleaire, IN2P3-CNRS, Universite Paris Sud, F-91406 Orsay (France); Barreau, G.; Jurado, B. [Centre d'Etudes Nucleaires de Bordeaux Gradignan--UMR 5797, CNRS/IN2P3-Universite Bordeaux 1, F-33175 Gradignan Cedex (France); Benlliure, J. [Universidade de Santiago de Compostela, E-15782 Santiago de Compostela (Spain)] (and others)

2009-11-15T23:59:59.000Z

423

Spontaneous-fission half-lives of deformed superheavy nuclei  

Science Journals Connector (OSTI)

Spontaneous-fission half-lives of the heaviest nuclei are analyzed in a multidimensional deformation space. They are calculated in a dynamical approach, without any adjustable parameters. The potential energy is obtained by the macroscopic-microscopic method and the inertia tensor by the cranking method. The action integral is minimized by a variational procedure. Even-even nuclei with proton number Z=104–114 and neutron number N=142–176 are considered. The results reproduce existing experimental data rather well. Relatively long half-lives are predicted for many unknown nuclei, sufficient to detect them if synthesized in a laboratory.

R. Smola?czuk; J. Skalski; A. Sobiczewski

1995-10-01T23:59:59.000Z

424

Nuclear choices  

SciTech Connect

This book contains part of the series New Liberal Arts, which is intended to make science and technology more accessible to students of the liberal arts. Volume in hand provides a comprehensive, multifaceted examination of nuclear energy, in nontechnical terms. Wolfson explains the basics of nuclear energy and radiation, nuclear power..., and nuclear weapons..., and he invites readers to make their own judgments on controversial nuclear issues. Illustrated with photos and diagrams. Each chapter contains suggestions for additional reading and a glossary. For policy, science, and general collections in all libraries. (ES) Topics contained include Atoms and nuclei. Effects and uses of radiation. Energy and People. Reactor safety. Nuclear strategy. Defense in the nuclear age. Nuclear power, nuclear weapons, and nuclear futures.

Wolfson, R.

1991-01-01T23:59:59.000Z

425

Americium and curium total half-lives and for the spontaneous fission branch  

SciTech Connect

The long-lived nuclides of the americium and curium elements are of interest for their use in certain safeguard applications and for nuclear reactor burnup studies in waste management. Recommended values are presented for /sup 241,242m,243/Am, and for /sup 242,243,244,245,246,247,248,250/Cm. These values result from a consistent evaluation of all these half-lives. These preliminary estimates were presented earlier. The uncertainties are provided at the 95% confidence limit for each of the recommended values. It will be noted that many of the recommended errors considerably exceed errors quoted by individual authors in their publication, by up to an order of magnitude, e.g. the total half-life of /sup 242,246,248/Cm and the spontaneous fission half-life of /sup 244/Cm. These preliminary estimates for the half-lives were given previously. Efforts continue to reevaluate the various experiments to better gauge the systematic errors involved and reassess the total error.

Holden, N.E.

1985-01-01T23:59:59.000Z

426

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

SciTech Connect

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

Henager, Charles H.; Jiang, Weilin

2014-11-01T23:59:59.000Z

427

Differential evolution Markov chain with snooker updater and fewer chains  

SciTech Connect

Differential Evolution Markov Chain (DE-MC) is an adaptive MCMC algorithm, in which multiple chains are run in parallel. Standard DE-MC requires at least N=2d chains to be run in parallel, where d is the dimensionality of the posterior. This paper extends DE-MC with a snooker updater and shows by simulation and real examples that DE-MC can work for d up to 50--100 with fewer parallel chains (e.g. N=3) by exploiting information from their past by generating jumps from differences of pairs of past states. This approach extends the practical applicability of DE-MC and is shown to be about 5--26 times more efficient than the optimal Normal random walk Metropolis sampler for the 97.5% point of a variable from a 25--50 dimensional Student T{sub 3} distribution. In a nonlinear mixed effects model example the approach outperformed a block-updater geared to the specific features of the model.

Vrugt, Jasper A [Los Alamos National Laboratory; Ter Braak, Cajo J F [NON LANL

2008-01-01T23:59:59.000Z

428

A Neural Network Model for the Tomographic Analysis of Irradiated Nuclear Fuel Rods  

SciTech Connect

A tomographic method based on a multilayer feed-forward artificial neural network is proposed for the reconstruction of gamma-radioactive fission product distribution in irradiated nuclear fuel rods. The quality of the method is investigated as compared to a conventional technique on experimental results concerning a Canada deuterium uranium reactor (CANDU)-type fuel rod irradiated in a TRIGA reactor.

Craciunescu, Teddy [National Institute of Nuclear Physics and Engineering (Romania)

2004-04-15T23:59:59.000Z

429

Research in heavy-ion nuclear physics. Annual progress report, May 1, 1991--April 30, 1992  

SciTech Connect

This report discusses the following topics: Fusion-fission in light nuclear systems; High-resolution Q-value measurement for the {sup 24}Mg+{sup 24}Mg reaction; Heavy-ion reactions and limits to fusion; and Hybrid MWPC-Bragg curve detector development.

Sanders, S.J.; Prosser, F.W.

1992-01-01T23:59:59.000Z

430

Effect of Nuclear Data Libraries on Tritium Breeding in a (D–T) Fusion Driven Reactor  

Science Journals Connector (OSTI)

In design a Deuterium–Tritium (D–T) fusion driven hybrid reactor, neutronics and nuclear data libraries have an...2O, LiH, Li2TiO3, Li2ZrO3 and Li4SiO4 in a (D–T) driven fusion–fission (hybrid) reactor is investi...

Adem Ac?r

2008-12-01T23:59:59.000Z

431

Muon Tracking to Detect Special Nuclear Materials  

SciTech Connect

Previous experiments have proven that nuclear assemblies can be imaged and identified inside of shipping containers using vertical trajectory cosmic-ray muons with two-sided imaging. These experiments have further demonstrated that nuclear assemblies can be identified by detecting fission products in coincidence with tracked muons. By developing these technologies, advanced sensors can be designed for a variety of warhead monitoring and detection applications. The focus of this project is to develop tomographic-mode imaging using near-horizontal trajectory muons in conjunction with secondary particle detectors. This will allow imaging in-situ without the need to relocate the objects and will enable differentiation of special nuclear material (SNM) from other high-Z materials.

Schwellenbach, D. [NSTec; Dreesen, W. [NSTec; Green, J. A. [NSTec; Tibbitts, A. [NSTec; Schotik, G. [NSTec; Borozdin, K. [LANL; Bacon, J. [LANL; Midera, H. [LANL; Milner, C. [LANL; Morris, C. [LANL; Perry, J. [LANL; Barrett, S. [UW; Perry, K. [UW; Scott, A. [UW; Wright, C. [UW; Aberle, D. [NSTec

2013-03-18T23:59:59.000Z

432

Shutdown system for a nuclear reactor  

DOE Patents (OSTI)

An ultimate shutdown system is provided for termination of neutronic activity in a nuclear reactor. The shutdown system includes bead chains comprising spherical containers suspended on a flexible cable. The containers are comprised of mating hemispherical shells which provide a ruggedized enclosure for reactor poison material. The bead chains, normally suspended above the reactor core on storage spools, are released for downward travel upon command from an external reactor monitor. The chains are capable of horizontal movement, so as to flow around obstructions in the reactor during their downward motion.

Groh, Edward F. (Naperville, IL); Olson, Arne P. (Western Springs, IL); Wade, David C. (Naperville, IL); Robinson, Bryan W. (Oak Lawn, IL)

1984-01-01T23:59:59.000Z

433

Measurement and Analysis of Fission Rates in a Spherical Mockup of Uranium and Polyethylene  

E-Print Network (OSTI)

Measurements of the reaction rate distribution were carried out using two kinds of Plate Micro Fission Chamber(PMFC). The first is a depleted uranium chamber and the second an enriched uranium chamber. The material in the depleted uranium chamber is strictly the same as the material in the uranium assembly. With the equation solution to conduct the isotope contribution correction, the fission rate of 238U and 235U were obtained from the fission rate of depleted uranium and enriched uranium. And then, the fission count of 238U and 235U in an individual uranium shell was obtained. In this work, MCNP5 and continuous energy cross sections ENDF/BV.0 were used for the analysis of fission rate distribution and fission count. The calculated results were compared with the experimental ones. The calculation of fission rate of DU and EU were found to agree with the measured ones within 10% except at the positions in polyethylene region and the two positions near the outer surface. Beacause the fission chamber was not co...

Tong-Hua, Zhu; Xin-Xin, Lu; Rong, Liu; Zi-Jie, Han; Li, Jiang; Mei, Wang

2013-01-01T23:59:59.000Z

434

Structural basis for recruitment of mitochondrial fission complexes by Fis1  

E-Print Network (OSTI)

Structural basis for recruitment of mitochondrial fission complexes by Fis1 Yan Zhang and David C mitochondrial fission complex, the outer membrane protein Fis1 recruits the dynamin-related GTPase Dnm1 to mitochondria. Fis1 contains a tetratricopeptide repeat (TPR) domain and interacts with Dnm1 via the molecular

Chan, David

435

Dispersion of the Neutron Emission in U{sup 235} Fission  

DOE R&D Accomplishments (OSTI)

Equations are developed which allow the calculation of the average number of neutrons per U{sup235} fission from experimental measurements. Experimental methods are described, the results of which give a value of (7.8 + 0.6){sup ?} neutrons per U{sup 235} thermal fission.

Feynman, R. P.; de Hoffmann, F.; Serber, R.

1955-00-00T23:59:59.000Z

436

The neutronics studies of fusion fission hybrid power reactor  

SciTech Connect

In this paper, a series of neutronics analysis of hybrid power reactor is proposed. The ideas of loading different fuels in a modular-type fission blanket is analyzed, fitting different level of fusion developments, i.e., the current experimental power output, the level can be obtained in the coming future and the high-power fusion reactor like ITER. The energy multiplication of fission blankets and tritium breeding ratio are evaluated as the criterion of design. The analysis is implemented based on the D-type simplified model, aiming to find a feasible 1000MWe hybrid power reactor for 5 years' lifetime. Three patterns are analyzed: 1) for the low fusion power, the reprocessed fuel is chosen. The fuel with high plutonium content is loaded to achieve large energy multiplication. 2) For the middle fusion power, the spent fuel from PWRs can be used to realize about 30 times energy multiplication. 3) For the high fusion power, the natural uranium can be directly used and about 10 times energy multiplication can be achieved.

Zheng Youqi; Wu Hongchun; Zu Tiejun; Yang Chao; Cao Liangzhi [School of Nuclear Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049 (China)

2012-06-19T23:59:59.000Z

437

(COMEDIE program review and fission product transport in MHTGR reactor)  

SciTech Connect

The subcontract between Martin Marietta Energy Systems, Inc., and the CEA provides for the refurbishment of the high pressure COMEDIE test loop in the SILOE reactor and a series of experiments to characterize fission product lift-off from MHTGR heat exchanger surfaces under several depressurization accident scenarios. The data will contribute to the validation of models and codes used to predict fission product transport in the MHTGR. In the meeting at CEA headquarters in Paris the program schedule and preparation for the DCAA and Quality Assurance audits were discussed. Long-range interest in expanded participation in the gas-cooled reactor technology Umbrella Agreement was also expressed by the CEA. At the CENG, in Grenoble, technical details on the loop design, fabrication components, development of test procedures, and preparation for the DOE quality assurance (QA) audit in May were discussed. After significant delays in CY 1989 it appears that good progress is being made in CY 1990 and the first major test will be initiated by December. An extensive list of agreements and commitments was generated to facilitate the coordination and planning of future work. 2 figs., 2 tabs.

Stansfield, O.M.

1990-03-15T23:59:59.000Z

438

Nuclear waste management. Quarterly progress report, October-December 1979  

SciTech Connect

Progress and activities are reported on the following: high-level waste immobilization, alternative waste forms, nuclear waste materials characterization, TRU waste immobilization programs, TRU waste decontamination, krypton solidification, thermal outgassing, iodine-129 fixation, monitoring of unsaturated zone transport, well-logging instrumentation development, mobile organic complexes of fission products, waste management system and safety studies, assessment of effectiveness of geologic isolation systems, waste/rock interactions technology, spent fuel and fuel pool integrity program, and engineered barriers. (DLC)

Platt, A.M.; Powell, J.A. (comps.)

1980-04-01T23:59:59.000Z

439

Nuclear waste management. Quarterly progress report, January-March 1980  

SciTech Connect

Reported are: high-level waste immobilization, alternative waste forms, nuclear waste materials characterization, TRU waste immobilization, TRU waste decontamination, krypton solidification, thermal outgassing, iodine-129 fixation, unsaturated zone transport, well-logging instrumentation development, mobile organic complexes of fission products, waste management system and safety studies, assessment of effectiveness of geologic isolation systems, waste/rock interactions, engineered barriers, criteria for defining waste isolation, and spent fuel and pool component integrity. (DLC)

Platt, A.M.; Powell, J.A. (comps.)

1980-06-01T23:59:59.000Z

440

The case for more nuclear power in Finland  

Science Journals Connector (OSTI)

A robust energy mix is a feasible system which is least sensitive to uncertainties and undesirable developments. Increased energy efficiency and more benign energy forms are obviously elements of a preferable energy mix but they alone cannot constitute a robust energy policy. A wide window is left for nuclear fission to contribute towards meeting the world's energy needs before these benign energy technologies will be in place, whatever they turn out to be.

P. Silvennoinen

1991-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "nuclear fission chain" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Government research and development summaries: Nuclear project briefs. Irregular  

SciTech Connect

Nuclear, Te, Ti Project Briefs describe the status of all R D program submitted to the Power Information Center by the government sponsors in energy conversion from fission, fusion, and radioisotope power sources and other thermal systems that use thermionic systems. These briefs also follow related investigations of plasma dynamics. The document is not to be reproduced, in whole or in part, for dissemination outside your own organization nor may it be reproduced for advertising or sales promotion purposes.

Not Available

1993-01-01T23:59:59.000Z

442

Government research and development summaries: Nuclear project briefs. Irregular  

SciTech Connect

Nuclear, Te, Ti Project Briefs describe the status of all R D program submitted to the Power Information Center by the government sponsors in energy conversion from fission, fusion, and radioisotope power sources and other thermal systems that use thermionic systems. These briefs also follow related investigations of plasma dynamics. The document is not to be reproduced, in whole or in part, for dissemination outside your own organization nor may it be reproduced for advertising or sales promotion purposes.

Not Available

1994-01-01T23:59:59.000Z

443

Process to separate transuranic elements from nuclear waste  

DOE Patents (OSTI)

A process for removing transuranic elements from a waste chloride electrolytic salt containing transuranic elements in addition to rare earth and other fission product elements so the salt waste may be disposed of more easily and the valuable transuranic elements may be recovered for reuse. The salt is contacted with a cadmium-uranium alloy which selectively extracts the transuranic elements from the salt. The waste salt is generated during the reprocessing of nuclear fuel associated with the Integral Fast Reactor (IFR).

Johnson, Terry R. (Wheaton, IL); Ackerman, John P. (Downers Grove, IL); Tomczuk, Zygmunt (Orland Park, IL); Fischer, Donald F. (Glen Ellyn, IL)

1989-01-01T23:59:59.000Z

444

Validation of the neutron and gamma fields in the JSI TRIGA reactor using in-core fission and ionization chambers  

Science Journals Connector (OSTI)

Abstract CEA developed fission chambers and ionization chambers were utilized at the JSI TRIGA reactor to measure neutron and gamma fields. The measured axial fission rate distributions in the reactor core are generally in good agreement with the calculated values using the Monte Carlo model of the reactor thus verifying both the computational model and the fission chambers. In future, multiple absolutely calibrated fission chambers could be used for more accurate online reactor thermal power monitoring.

Gašper Žerovnik; Tanja Kaiba; Vladimir Radulovi?; Anže Jazbec; Sebastjan Rupnik; Loïc Barbot; Damien Fourmentel; Luka Snoj

2015-01-01T23:59:59.000Z

445

defense nuclear security | National Nuclear Security Administration  

National Nuclear Security Administration (NNSA)

nuclear security | National Nuclear Security Administration People Mission Managing the Stockpile Preventing Proliferation Powering the Nuclear Navy Emergency Response...

446

Chernobyl Nuclear Accident | National Nuclear Security Administration  

National Nuclear Security Administration (NNSA)

Chernobyl Nuclear Accident | National Nuclear Security Administration People Mission Managing the Stockpile Preventing Proliferation Powering the Nuclear Navy Emergency Response...

447

Countering Nuclear Terrorism and Trafficking | National Nuclear...  

National Nuclear Security Administration (NNSA)

Countering Nuclear Terrorism and Trafficking | National Nuclear Security Administration People Mission Managing the Stockpile Preventing Proliferation Powering the Nuclear Navy...

448

MANAGING BERYLLIUM IN NUCLEAR FACILITY APPLICATIONS  

SciTech Connect

Beryllium plays important roles in nuclear facilities. Its neutron multiplication capability and low atomic weight make it very useful as a reflector in fission reactors. Its low atomic number and high chemical affinity for oxygen have led to its consideration as a plasma-facing material in fusion reactors. In both applications, the beryllium and the impurities in it become activated by neutrons, transmuting them to radionuclides, some of which are long-lived and difficult to dispose of. Also, gas production, notably helium and tritium, results in swelling, embrittlement, and cracking, which means that the beryllium must be replaced periodically, especially in fission reactors where dimensional tolerances must be maintained. It has long been known that neutron activation of inherent iron and cobalt in the beryllium results in significant {sup 60}Co activity. In 2001, it was discovered that activation of naturally occurring contaminants in the beryllium creates sufficient {sup 14}C and {sup 94}Nb to render the irradiated beryllium 'Greater-Than-Class-C' for disposal in U.S. radioactive waste facilities. It was further found that there was sufficient uranium impurity in beryllium that had been used in fission reactors up to that time that the irradiated beryllium had become transuranic in character, making it even more difficult to dispose of. In this paper we review the extent of the disposal issue, processes that have been investigated or considered for improving the disposability of irradiated beryllium, and approaches for recycling.

R. Rohe; T. N. Tranter

2011-12-01T23:59:59.000Z

449

Chapter 1 - What Is Nuclear Fusion?  

Science Journals Connector (OSTI)

Publisher Summary This chapter reviews the history of nuclear fusion, and states how in the 20th century it became possible to split an atom through nuclear fission, or combine them together using nuclear fusion. Only in the early 20th century was it realized that nuclear fusion is the energy source that runs the universe and that simultaneously it is the mechanism responsible for creating all the different chemical elements in the world. The chapter talks about the Sun's energy, and points out how the work of Albert Einstein, Francis Aston, and Arthur Eddington led to the realization that the energy radiated by the sun and the stars is because of nuclear fusion. However, it was only after quantum mechanics was developed that a complete understanding of nuclear fusion came about. The chapter also discusses how researchers realized that mass can be turned into energy, especially Otto Hahn and Fritz Strassman, who demonstrated that the uranium atom could be split by bombarding uranium with neutrons, giving way to the release of a large amount of energy. Man-made suns are discussed next, reviewing the experiments done on attempts at harnessing fusion energy. Finally, the development of nuclear power plants is briefly discussed in the chapter.

Garry McCracken; Peter Stott

2005-01-01T23:59:59.000Z

450

Spent nuclear fuel reprocessing modeling  

SciTech Connect

The long-term wide development of nuclear power requires new approaches towards the realization of nuclear fuel cycle, namely, closed nuclear fuel cycle (CNFC) with respect to fission materials. Plant nuclear fuel cycle (PNFC), which is in fact the reprocessing of spent nuclear fuel unloaded from the reactor and the production of new nuclear fuel (NF) at the same place together with reactor plant, can be one variant of CNFC. Developing and projecting of PNFC is a complicated high-technology innovative process that requires modern information support. One of the components of this information support is developed by the authors. This component is the programme conducting calculations for various variants of process flow sheets for reprocessing SNF and production of NF. Central in this programme is the blocks library, where the blocks contain mathematical description of separate processes and operations. The calculating programme itself has such a structure that one can configure the complex of blocks and correlations between blocks, appropriate for any given flow sheet. For the ready sequence of operations balance calculations are made of all flows, i.e. expenses, element and substance makeup, heat emission and radiation rate are determined. The programme is open and the block library can be updated. This means that more complicated and detailed models of technological processes will be added to the library basing on the results of testing processes using real equipment, in test operating mode. The development of the model for the realization of technical-economic analysis of various variants of technologic PNFC schemes and the organization of 'operator's advisor' is expected. (authors)

Tretyakova, S.; Shmidt, O.; Podymova, T.; Shadrin, A.; Tkachenko, V. [Bochvar Institute, 5 Rogova str., Moscow 123098 (Russian Federation); Makeyeva, I.; Tkachenko, V.; Verbitskaya, O.; Schultz, O.; Peshkichev, I. [Russian Federal Nuclear Center - VNIITF E.I. Zababakhin, p.o.box 245, Snezhinsk, 456770 (Russian Federation)

2013-07-01T23:59:59.000Z

451

SciTech Connect: Microscopic Theory of Fission  

Office of Scientific and Technical Information (OSTI)

Relation: Conference: Presented at: Compound Nuclear Reactions and Related Topics, Fish Camp, CA, United States, Oct 22 - Oct 26, 2007 Research Org: Lawrence Livermore...

452

Nuclear Science  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Science Science and Engineering Education Sourcebook 2013 American Nuclear Society US Department of Energy Nuclear Science & Engineering Education Sourcebook 2013 North American Edition American Nuclear Society Education, Training, and Workforce Division US Department of Energy Office of Nuclear Energy Editor and Founder John Gilligan Professor of Nuclear Engineering North Carolina State University Version 5.13 Welcome to the 2013 Edition of the Nuclear Science and Engineering Education (NS&EE) Sourcebook. We have evolved and improved! The core mission of the Sourcebook has not changed, however. Our purpose is to facilitate interaction among faculty, students, industry, and government agencies to accomplish nuclear research, teaching and service activities. Since 1986 we have compiled critical information on nuclear

453

Nuclear reactions  

Science Journals Connector (OSTI)

Much reference has been made in the last chapter to nuclear energy levels and their various properties (e.g ... ways of doing this — the use of nuclear reactions, and studies of how excited nuclei...

R. J. Blin-Stoyle FRS

1991-01-01T23:59:59.000Z

454

nuclear security  

National Nuclear Security Administration (NNSA)

3%2A en Shaping the future of nuclear detection http:nnsa.energy.govblogshaping-future-nuclear-detection

455

PHYSICAL REVIEW C VOLUME 46, NUMBER 1 JULY 1992 Nuclear fission with diffusive dynamics  

E-Print Network (OSTI)

is larger than the theoretical in the work of Bush, Bertsch, and Brown by a factor of 5--11. PACS number of giant dipole photons [4]. On the theoretical side, large amplitude shape dynamics is most commonly] is a factor of 5 different from the theoretical prediction, due mostly to the larger number of prescission

Bertsch George F.

456

THE CASE FOR FUSION-FISSION HYBRIDS ENABLING SUSTAINABLE NUCLEAR POWER  

E-Print Network (OSTI)

to produce energy, rather than storing them in geological repositories for hundreds of thousands of years (a uranium energy content recovered in present LWR "once-through" fuel cycles (uranium would be depleted it is the delayed neutron fraction, _. _ is 2-3 times smaller for transuranics (Pu, Am, Np..) than for uranium fuel

457

Climate Change, Nuclear Power and Nuclear Proliferation: Magnitude Matters  

SciTech Connect

Integrated energy, environment and economics modeling suggests that worldwide electrical energy use will increase from 2.4 TWe today to ~12 TWe in 2100. It will be challenging to provide 40% of this electrical power from combustion with carbon sequestration, as it will be challenging to provide 30% from renewable energy sources derived from natural energy flows. Thus nuclear power may be needed to provide ~30%, 3600 GWe, by 2100. Calculations of the associated stocks and flows of uranium, plutonium and minor actinides indicate that the proliferation risks at mid-century, using current light-water reactor technology, are daunting. There are institutional arrangements that may be able to provide an acceptable level of risk mitigation, but they will be difficult to implement. If a transition is begun to fast-spectrum reactors at mid-century, without a dramatic change in the proliferation risks of such systems, at the end of the century global nuclear proliferation risks are much greater, and more resistant to mitigation. Fusion energy, if successfully demonstrated to be economically competitive, would provide a source of nuclear power with much lower proliferation risks than fission.

Robert J. Goldston

2011-04-28T23:59:59.000Z

458

Cationic triple-chain amphiphiles facilitate vesicle fusion compared to double-chain or single-chain analogues  

E-Print Network (OSTI)

-chain analogues. Two types of vesicle fusion experiments were conducted, mixing of oppositely charged vesicles-determining step for certain cell types is endosomal escape, which can occur either by a fusion or disruptionCationic triple-chain amphiphiles facilitate vesicle fusion compared to double-chain or single

Smith, Bradley D.

459

Nuclear Ukraine  

Science Journals Connector (OSTI)

... SIR - Your article (Nature 365, 599; 1993) on the US-Ukraine stalemate over nuclear weapons prompts the following remarks. The United States made a mistake ... nuclear weapons prompts the following remarks. The United States made a mistake in not recognizing Ukraine as a legitimate successor state to the Soviet nuclear arsenal and is still insisting that ...

Arno Arrak

1994-01-13T23:59:59.000Z

460

ENDF/B-VII.0: Next Generation Evaluated Nuclear Data Library for Nuclear Science and Technology  

SciTech Connect

We describe the next generation general purpose Evaluated Nuclear Data File, ENDF/B-VII.0, of recommended nuclear data for advanced nuclear science and technology applications. The library, released by the U.S. Cross Section Evaluation Working Group (CSEWG) in December 2006, contains data primarily for reactions with incident neutrons, protons, and photons on almost 400 isotopes. The new evaluations are based on both experimental data and nuclear reaction theory predictions. The principal advances over the previous ENDF/B-VI library are the following: (1) New cross sections for U, Pu, Th, Np and Am actinide isotopes, with improved performance in integral validation criticality and neutron transmission benchmark tests; (2) More precise standard cross sections for neutron reactions on H, {sup 6}Li, {sup 10}B, Au and for {sup 235,238}U fission, developed by a collaboration with the IAEA and the OECD/NEA Working Party on Evaluation Cooperation (WPEC); (3) Improved thermal neutron scattering; (4) An extensive set of neutron cross sections on fission products developed through a WPEC collaboration; (5) A large suite of photonuclear reactions; (6) Extension of many neutron- and proton-induced reactions up to an energy of 150 MeV; (7) Many new light nucleus neutron and proton reactions; (8) Post-fission beta-delayed photon decay spectra; (9) New radioactive decay data; and (10) New methods developed to provide uncertainties and covariances, together with covariance evaluations for some sample cases. The paper provides an overview of this library, consisting of 14 sublibraries in the same, ENDF-6 format, as the earlier ENDF/B-VI library. We describe each of the 14 sublibraries, focusing on neutron reactions. Extensive validation, using radiation transport codes to simulate measured critical assemblies, show major improvements: (a) The long-standing underprediction of low enriched U thermal assemblies is removed; (b) The {sup 238}U, {sup 208}Pb, and {sup 9}Be reflector biases in fast systems are largely removed; (c) ENDF/B-VI.8 good agreement for simulations of highly enriched uranium assemblies is preserved; (d) The underprediction of fast criticality of {sup 233,235}U and {sup 239}Pu assemblies is removed; and (e) The intermediate spectrum critical assemblies are predicted more accurately. We anticipate that the new library will play an important role in nuclear technology applications, including transport simulations supporting national security, nonproliferation, advanced reactor and fuel cycle concepts, criticality safety, medicine, space applications, nuclear astrophysics, and nuclear physics facility design. The ENDF/B-VII.0 library is archived at the National Nuclear Data Center, BNL. The complete library, or any part of it, may be retrieved from www.nndc.bnl.gov.

Chadwick, M B; Oblozinsky, P; Herman, M; Greene, N M; McKnight, R D; Smith, D L; Young, P G; MacFarlane, R E; Hale, G M; Haight, R C; Frankle, S; Kahler, A C; Kawano, T; Little, R C; Madland, D G; Moller, P; Mosteller, R; Page, P; Talou, P; Trellue, H; White, M; Wilson, W B; Arcilla, R; Dunford, C L; Mughabghab, S F; Pritychenko, B; Rochman, D; Sonzogni, A A; Lubitz, C; Trumbull, T H; Weinman, J; Brown, D; Cullen, D E; Heinrichs, D; McNabb, D; Derrien, H; Dunn, M; Larson, N M; Leal, L C; Carlson, A D; Block, R C; Briggs, B; Cheng, E; Huria, H; Kozier, K; Courcelle, A; Pronyaev, V; der Marck, S

2006-10-02T23:59:59.000Z

Note: This page contains sample records for the topic "nuclear fission chain" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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461

Supply Chain Management Faculty Brian Fugate  

E-Print Network (OSTI)

relationships, strategy and sustainability in the supply chain, and she won the College of Business Excellence involvement in new product development, and sustainability practices in supply chain management. He has

462

An integrative framework for architecting supply chains  

E-Print Network (OSTI)

This thesis explores the limitations of classic models of supply chain management, and proposes a new view based on the concept of value-driven supply chains, and a method of analysis and design based on the concepts of ...

Cela Díaz, Fernando

2006-01-01T23:59:59.000Z

463

Thermal Performance of Deep-Burn Fusion-Fission Hybrid Waste in a Repository  

SciTech Connect

The Laser Inertial Confinement Fusion Fission Energy (LIFE) Engine [1] combines a neutron-rich but energy-poor inertial fusion system with an energy-rich but neutron-poor subcritical fission blanket. Because approximately 80% of the LIFE Engine energy is produced from fission, the requirements for laser efficiency and fusion target performance are relaxed, compared to a pure-fusion system, and hence a LIFE Engine prototype can be based on target performance in the first few years of operation of the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL). Similarly, because of the copious fusion neutrons, the fission blanket can be run in a subcritical, driven, mode, without the need for control rods or other sophisticated reactivity control systems. Further, because the fission blanket is inherently subcritical, fission fuels that can be used in LIFE Engine designs include thorium, depleted uranium, natural uranium, spent light water reactor fuel, highly enriched uranium, and plutonium. Neither enrichment nor reprocessing is required for the LIFE Engine fuel cycle, and burnups to 99% fraction of initial metal atoms (FIMA) being fissioned are envisioned. This paper discusses initial calculations of the thermal behavior of spent LIFE fuel following completion of operation in the LIFE Engine [2]. The three time periods of interest for thermal calculations are during interim storage (probably at the LIFE Engine site), during the preclosure operational period of a geologic repository, and after closure of the repository.

Blink, J A; Chipman, V; Farmer, J; Shaw, H; Zhao, P

2008-11-25T23:59:59.000Z

464

Nuclear energy density optimization: Shell structure  

E-Print Network (OSTI)

Nuclear density functional theory is the only microscopical theory that can be applied throughout the entire nuclear landscape. Its key ingredient is the energy density functional. In this work, we propose a new parameterization UNEDF2 of the Skyrme energy density functional. The functional optimization is carried out using the POUNDerS optimization algorithm within the framework of the Skyrme Hartree-Fock-Bogoliubov theory. Compared to the previous parameterization UNEDF1, restrictions on the tensor term of the energy density have been lifted, yielding a very general form of the energy density functional up to second order in derivatives of the one-body density matrix. In order to impose constraints on all the parameters of the functional, selected data on single-particle splittings in spherical doubly-magic nuclei have been included into the experimental dataset. The agreement with both bulk and spectroscopic nuclear properties achieved by the resulting UNEDF2 parameterization is comparable with UNEDF1. While there is a small improvement on single-particle spectra and binding energies of closed shell nuclei, the reproduction of fission barriers and fission isomer excitation energies has degraded. As compared to previous UNEDF parameterizations, the parameter confidence interval for UNEDF2 is narrower. In particular, our results overlap well with those obtained in previous systematic studies of the spin-orbit and tensor terms. UNEDF2 can be viewed as an all-around Skyrme EDF that performs reasonably well for both global nuclear properties and shell structure. However, after adding new data aiming to better constrain the nuclear functional, its quality has improved only marginally. These results suggest that the standard Skyrme energy density has reached its limits and significant changes to the form of the functional are needed.

M. Kortelainen; J. McDonnell; W. Nazarewicz; E. Olsen; P. -G. Reinhard; J. Sarich; N. Schunck; S. M. Wild; D. Davesne; J. Erler; A. Pastore

2013-12-06T23:59:59.000Z

465

Nuclear Engineer (Nuclear Safety Specialist)  

Energy.gov (U.S. Department of Energy (DOE))

A successful candidate of this position will serve as a Nuclear Engineer (Nuclear Safety Specialist) responsible for day-to-day technical monitoring, and evaluation of aspects of authorization...

466

Proc. 19th Winter Workshop on Nuclear Dynamics (2003) 000000  

E-Print Network (OSTI)

Abstract. I discuss a few of the recent developments in nuclear reactions at very low energies ends of the energy scale for nuclear reactions: (a) the very high and (b) the very low relative. At the other end of the energy scale are the low energy reactions of importance for stellar evolution. A chain

Bertulani, Carlos A. - Department of Physics and Astronomy, Texas A&M University

467

The Offshore Services Global Value Chain  

E-Print Network (OSTI)

The Offshore Services Global Value Chain ECONOMIC UPGRADING AND WORKFORCE DEVELOPMENT Karina & COMPETITIVENESS #12;The Offshore Services Global Value Chain: Economic Upgrading and Workforce Development "Skills & Competitiveness, Duke University Posted: November 17, 2011 #12;The Offshore Services Global Value Chain: Economic

Richardson, David

468

Nuclear Deterrence  

NLE Websites -- All DOE Office Websites (Extended Search)

Nuclear Deterrence Nuclear Deterrence Nuclear Deterrence LANL's mission is to develop and apply science and technology to ensure the safety, security, and effectiveness of the U.S. nuclear deterrent; reduce global threats; and solve other emerging national security and energy challenges. April 12, 2012 A B-2 Spirit bomber refuels from a KC-135 Stratotanker A B-2 Spirit bomber refuels from a KC-135 Stratotanker. Contact Operator Los Alamos National Laboratory (505) 667-5061 Charlie McMillan, Director: "For the last 70 years there has not been a world war, and I have to think that our strong deterrent has something to do with that fact." Mission nuclear weapons Charlie McMillan, Director of Los Alamos National Laboratory 1:06 Director McMillan on nuclear deterrence While the role and prominence of nuclear weapons in U.S. security policy

469

Nuclear Power Technology for the Future  

SciTech Connect

Ensuring sufficient energy for electricity, fresh water and transportation represents a major challenge for this century. Energy demand will increase dramatically as developing countries improve their standards of living. Nuclear power will become an increasingly important source of energy for production of electricity, fresh water and hydrogen as transportation fuel. Hydrocarbon sources of energy are not acceptable in the long term because of global warming and uneven supply. To ensure that nuclear power can meet this challenge, improved technologies are required to address the problems of nuclear waste, management of nuclear materials and safety as many more nuclear plants are built. These technologies are being developed at Argonne National Laboratory as part of the DOE international program of Generation IV reactors. Essential to meeting these challenges is the development of fast-spectrum nuclear reactors for which fuel and fission products are recycled to the reactor to be 'burned'. I will discuss work on fast-spectrum reactor and fuel-cycle design. The technologies discussed will be 'passively safe' reactor design and 'pyroprocessing' for fuel reprocessing.

Sackett, John I. (ANL) [ANL

2003-07-23T23:59:59.000Z

470

Deep Atomic Binding (DAB) Approach in Interpretation of Fission Products Behavior in Terrestrial and Water Ecosystems  

SciTech Connect

A large number of studies and models were established to explain the fission products (FP) behavior within terrestrial and water ecosystems, but a number of behaviors were non understandable, which always attributed to unknown reasons. According to DAB hypothesis, almost all fission products behaviors in terrestrial and water ecosystems could be interpreted in a wide coincidence. The gab between former models predictions, and field behavior of fission products after accidents like Chernobyl have been explained. DAB represents a tool to reduce radio-phobia as well as radiation protection expenses. (author)

Ajlouni, Abdul-Wali M.S. [Ministry of Energy and Mineral Resources, Amman 11814 (Jordan)

2006-07-01T23:59:59.000Z

471

Radiological Aspects of Deep-Burn Fusion-Fission Hybrid Waste in a Repository  

SciTech Connect

The quantity, radioactivity, and isotopic characteristics of the spent fission fuel from a hybrid fusion-fission system capable of extremely high burnups are described. The waste generally has higher activity per unit mass of heavy metal, but much lower activity per unit energy generated. The very long-term radioactivity is dominated by fission products. Simple scaling calculations suggest that the dose from a repository containing such waste would be dominated by {sup 129}I, {sup 135}Cs, and {sup 242}Pu. Use of such a system for generating energy would greatly reduce the need for repository capacity.

Shaw, H F; Blink, J A; Farmer, J C; Karmer, K J; Latkowski, J F; Zhao, P

2008-11-25T23:59:59.000Z

472

Natural fission reactors in the Franceville basin, Gabon: A review of the conditions and results of a {open_quotes}critical event{close_quotes} in a geologic system  

SciTech Connect

Natural nuclear fission reactors are only known in two uranium deposits in the world, the Oklo and Bangombe deposits of the Franceville basin: Gabon. Since 1982, five new reactor zones have been discovered in these deposits and studied since 1989 in a cooperative European program. New geological, mineralogical, and geochemical studies have been carried out in order to understand the behavior of the actinides and fission products which have been stored in a geological environment for more than 2.0 Ga years. The Franceville basin and the uranium deposits remained geologically stable over a long period of time. Therefore, the sites of Oklo and Bangombe are well preserved. For the reactors, two main periods of actinide and radionuclides migration have been observed: during the criticality, under P-T conditions of 300 bars and 400-500{degrees}C, respectively, and during a distention event which affected the Franceville basin 800 to 900 Ma ago and which was responsible for the intrusion of dolerite dikes close to the reactors. New isotopic analyses on uranium dioxides, clays, and phosphates allow us to determine their respective importance for the retention of fission products. The UO{sub 2} matrix appears to be efficient at retaining most actinides and fission products such as REEs, Y, and Zr but not the volatile fission products (Cd, Cs, Xe, and Kr) nor Rb, Sr, and Ba. Some fissiogenic elements such as Mo, Tc, Ru, Rh, Pd, and Te could have formed metallic and oxide inclusion in the UO{sub 2} matrix which are similar to those observed in artificial spent fuel. Clays and phosphate minerals also appear to have played a role in the retention of fissiogenic REEs and also of Pu. 82 refs., 21 figs., 12 tabs.

Gauthier-Lafaye, F. [CNRS, Strasbourg (France)] [CNRS, Strasbourg (France); Holliger, P. [CEA-Cadarache, Saint-Paul-les-Durance (France)] [CEA-Cadarache, Saint-Paul-les-Durance (France); Blanc, P.L. [Institut de Protection et de Surete Nucleaire, Fontenay-aux-Roses (France)] [Institut de Protection et de Sur