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1

Lesson 5- Fission and Chain Reactions  

Broader source: Energy.gov [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.

2

Fission decay in intermediate heavy ion reactions  

SciTech Connect (OSTI)

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

3

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

4

A novel capillary polymerase chain reaction machine  

E-Print Network [OSTI]

I built a novel prototype capillary polymerase chain reaction machine. The purpose was to perform a single reaction as fast as possible with a reaction volume - 100 nl. The PCR mix is in the form of a 1 /1 droplet that ...

Chiou, Jeffrey Tsungshuan

2001-01-01T23:59:59.000Z

5

Nuclear chain reaction: forty years later  

SciTech Connect (OSTI)

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

6

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...

7

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

8

Electrochemical Branched-DNA Assay for Polymerase Chain Reaction...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Branched-DNA Assay for Polymerase Chain Reaction-Free Detection and Quantification of Oncogenes in Messenger RNA Electrochemical Branched-DNA Assay for Polymerase Chain...

9

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

10

Dual phase multiplex polymerase chain reaction  

DOE Patents [OSTI]

Highly specific and sensitive methods were developed for multiplex amplification of nucleic acids on supports such as microarrays. Based on a specific primer design, methods include five types of amplification that proceed in a reaction chamber simultaneously. These relate to four types of multiplex amplification of a target DNA on a solid support, directed by forward and reverse complex primers immobilized to the support and a fifth type--pseudo-monoplex polymerase chain reaction (PCR) of multiple targets in solution, directed by a single pair of unbound universal primers. The addition of the universal primers in the reaction mixture increases the yield over the traditional "bridge" amplification on a solid support by approximately ten times. Methods that provide multitarget amplification and detection of as little as 0.45-4.5.times.10.sup.-12 g (equivalent to 10.sup.2-10.sup.3 genomes) of a bacterial genomic DNA are disclosed.

Pemov, Alexander (Charlottesville, VA); Bavykin, Sergei (Darien, IL)

2008-10-07T23:59:59.000Z

11

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

12

Integrated polymerase chain reaction/electrophoresis instrument  

DOE Patents [OSTI]

A new approach and instrument for field identification of micro-organisms and DNA fragments using a small and disposable device containing integrated polymerase chain reaction (PCR) enzymatic reaction wells, attached capillary electrophoresis (CE) channels, detectors, and read-out all on/in a small hand-held package. The analysis instrument may be made inexpensively, for example, of plastic, and thus is disposable, which minimizes cross contamination and the potential for false positive identification between samples. In addition, it is designed for multiple users with individual applications. The integrated PCR/CE is manufactured by the PCR well and CE channels are "stamped" into plastic depressions where conductive coatings are made in the wells and ends of the CE microchannels to carry voltage and current to heat the PCR reaction mixtures and simultaneously draw DNA bands up the CE channels. Light is transmitted through the instrument at appropriate points and detects PCR bands and identifies DNA fragments by size (retention time) and quantifies each by the amount of light generated as each phototransistor positioned below each CE channel detects a passing band. The instrument is so compact that at least 100 PCR/CE reactions/analyses can be performed easily on one detection device.

Andresen, Brian D. (Livermore, CA)

2000-01-01T23:59:59.000Z

13

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

SciTech Connect (OSTI)

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

14

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

15

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

16

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

17

The Polymerase Chain Reaction and Branching Processes Fengzhu Sun  

E-Print Network [OSTI]

The Polymerase Chain Reaction and Branching Processes Fengzhu Sun Department of Mathematics, DRB is studied. We also study the distribution of the Hamming distance between two randomly chosen sequences long. The double-stranded DNA molecules are heated to near boiling temperature so that the double

Sun, Fengzhu - Sun, Fengzhu

18

Polymerase chain reaction: detection of varicella-zoster virus.  

Science Journals Connector (OSTI)

...detection of varicella-zoster virus. T Fenner A Kropec J Hubner Polymerase chain reaction...viral diagnostic tool. REFERENCES 1. Fenner, T., J. Garweg, F. Hufert, M...Clin. Microbiol. 29:76-79. Thomas Fenner Andrea Kropec Johannes Hubner Department...

T Fenner; A Kropec; J Hübner

1993-02-01T23:59:59.000Z

19

Prompt fission neutron multiplicity and spectrum calculations for thermal and fast neutron induced reactions on 233,231Pa nuclei  

Science Journals Connector (OSTI)

The prompt fission neutron multiplicity and spectra of 233Pa(n, f) and 231Pa(n, f) were calculated for incident neutron energies up to 50 MeV and 30 MeV, respectively using refined neutron evaporation models. Those models have been already successfully applied to calculate the prompt neutron multiplicities and spectra for many actinides. The unique experimental data concerning the fission fragment mass distribution and total kinetic energy for the 234,233,232Pa fissioning nuclei were exploited in the frame of the Point-by-Point treatment. The total average prompt neutron multiplicity, the fission fragment pair multiplicity and the multiplicity dependence on fragment mass (sawtooth) for the reactions 233,232,231Pa(nth, f) and the average values of the model parameters for 234-232Pa fissioning nuclei were calculated. For the other Pa fissioning nuclei involved in the studied reactions relevant parameters were established following systematic trends. Due to a total lack of experimental prompt fission neutron multiplicity and spectrum data for Pa isotopes, the present results were compared with systematic trends following from neighboring actinides. The calculated prompt fission neutron multiplicity as well as the prompt ?-ray energy of the 233,231Pa(n, f) reactions are obtained in very good agreement with all systematic trends.

Anabella Tudora; G. Vladuca; F.-J. Hambsch; D. Filipescu; S. Oberstedt

2008-01-01T23:59:59.000Z

20

Polymerase chain reaction system using magnetic beads for analyzing a sample that includes nucleic acid  

DOE Patents [OSTI]

A polymerase chain reaction system for analyzing a sample containing nucleic acid includes providing magnetic beads; providing a flow channel having a polymerase chain reaction chamber, a pre polymerase chain reaction magnet position adjacent the polymerase chain reaction chamber, and a post pre polymerase magnet position adjacent the polymerase chain reaction chamber. The nucleic acid is bound to the magnetic beads. The magnetic beads with the nucleic acid flow to the pre polymerase chain reaction magnet position in the flow channel. The magnetic beads and the nucleic acid are washed with ethanol. The nucleic acid in the polymerase chain reaction chamber is amplified. The magnetic beads and the nucleic acid are separated into a waste stream containing the magnetic beads and a post polymerase chain reaction mix containing the nucleic acid. The reaction mix containing the nucleic acid flows to an analysis unit in the channel for analysis.

Nasarabadi, Shanavaz (Livermore, CA)

2011-01-11T23:59:59.000Z

Note: This page contains sample records for the topic "fission chain reaction" 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

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

22

Fusion-fission and quasifission in the reactions with heavy ions leading to the formation of Hs  

SciTech Connect (OSTI)

Mass and energy distributions of binary reaction products obtained in the reactions {sup 22}Ne+{sup 249}Cf,{sup 26}Mg+{sup 248}Cm,{sup 36}S+{sup 238}U and {sup 58}Fe+{sup 208}Pb leading to Hs isotopes have been measured. At energies below the Coulomb barrier the bimodal fission of Hs*, formed in the reaction {sup 26}Mg+{sup 248}Cm, is observed. In the reaction {sup 36}S+{sup 238}U the considerable part of the symmetric fragments arises from the quasifission process. At energies above the Coulomb barrier the symmetric fragments originate mainly from fusion-fission process for both reactions with Mg and S ions. In the case of the {sup 58}Fe+{sup 208}Pb reaction the quasifission process dominates at all measured energies. The pre- and post-scission neutron multiplicities as a function of the fragment mass have been obtained for the reactions studied.

Itkis, I. M.; Itkis, M. G.; Knyazheva, G. N.; Kozulin, E. M. [Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation)

2012-10-20T23:59:59.000Z

23

Fission and quasifission modes in heavy-ion-induced reactions leading to the formation of Hs{sup *}  

SciTech Connect (OSTI)

Mass and energy distributions of binary reaction products obtained in the reactions {sup 22}Ne+{sup 249}Cf,{sup 26}Mg+{sup 248}Cm, {sup 36}S+{sup 238}U, and {sup 58}Fe+{sup 208}Pb have been measured. All reactions lead to Hs isotopes. At energies below the Coulomb barrier the bimodal fission of Hs{sup *}, formed in the reaction {sup 26}Mg+{sup 248}Cm, is observed. In the reaction {sup 36}S+{sup 238}U, leading to the formation of a similar compound nucleus, the main part of the symmetric fragments arises from the quasifission process. At energies above the Coulomb barrier fusion-fission is the main process leading to the formation of symmetric fragments for both reactions with Mg and S ions. In the case of the {sup 58}Fe+{sup 208}Pb reaction the quasifission process dominates at all measured energies.

Itkis, I. M.; Kozulin, E. M.; Itkis, M. G.; Knyazheva, G. N.; Bogachev, A. A.; Chernysheva, E. V.; Krupa, L.; Oganessian, Yu. Ts.; Zagrebaev, V. I.; Rusanov, A. Ya.; Goennenwein, F.; Dorvaux, O.; Stuttge, L.; Hanappe, F.; Vardaci, E.; Goes Brennand, E. de [Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Institute of Nuclear Physics of the National Nuclear Center of Kazakhstan, 050032 Almaty (Kazakhstan); Physikalisches Institut, Universitaet Tuebingen, D-72076 Tuebingen (Germany); Institut Pluridisciplinaire Hubert Curien and Universite de Strasbourg, F-67037 Strasbourg (France); Universite Libre de Bruxelles, CP229, B-1050 Bruxelles, Belgique (Belgium); Istituto Nazionale di Fisica Nucleare and Dipartimento di Scienze Fisiche dell'Universita di Napoli, Napoli (Italy); Departamento de Fisica, Universidade Estadual da Paraiba, 58109-753 Campina Grande (Brazil)

2011-06-15T23:59:59.000Z

24

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

25

Nested methylation-specific polymerase chain reaction cancer detection method  

DOE Patents [OSTI]

A molecular marker-based method for monitoring and detecting cancer in humans. Aberrant methylation of gene promoters is a marker for cancer risk in humans. A two-stage, or "nested" polymerase chain reaction method is disclosed for detecting methylated DNA sequences at sufficiently high levels of sensitivity to permit cancer screening in biological fluid samples, such as sputum, obtained non-invasively. The method is for detecting the aberrant methylation of the p16 gene, O 6-methylguanine-DNA methyltransferase gene, Death-associated protein kinase gene, RAS-associated family 1 gene, or other gene promoters. The method offers a potentially powerful approach to population-based screening for the detection of lung and other cancers.

Belinsky, Steven A. (Albuquerque, NM); Palmisano, William A. (Edgewood, NM)

2007-05-08T23:59:59.000Z

26

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...

27

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

28

Identifying of meat species using polymerase chain reaction (PCR)  

SciTech Connect (OSTI)

Meat has been widely consumed as an important protein source in daily life of human. Furthermore, with busy and intense urban lifestyle, processed food is now one of the main protein sources of one’s diet. Consumers rely on the food labeling to decide if the meat product purchased is safe and reliable. Therefore, it is important to ensure the food labeling is done in a correct manner to avoid consumer fraud. More consumers are now concern about the food quality and safety as compared to before. This study described the meat species identification and detection method using Polymerase Chain Reaction (PCR) in 8 types of meats (cattle, buffalo, goat, sheep, chicken, duck, pork and horse). The objective of this study is to decide on the specificity of oligonucleotide sequences obtained from previous study. There were 5 proposed oligonucleotide primer in this study. The main important finding in this work is the specificity of oligonucleotide primers to raw meats. It if found that the oligonucleotide primers proposed were not specific to the local raw meat species. Therefore, further study is needed to obtain a species-specific oligonucletide primers for PCR, in order to be applied in food product testing.

Foong, Chow Ming; Sani, Norrakiah Abdullah [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor (Malaysia)

2013-11-27T23:59:59.000Z

29

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

30

Precise ruthenium fission product isotopic analysis using dynamic reaction cell inductively coupled plasma mass spectrometry (DRC-ICP-MS)  

SciTech Connect (OSTI)

99Tc is a subsurface contaminant of interest at numerous federal, industrial, and international facilities. However, as a mono-isotopic fission product, 99Tc lacks the ability to be used as a signature to differentiate between the different waste disposal pathways that could have contributed to subsurface contamination at these facilities. Ruthenium fission-product isotopes are attractive analogues for the characterization of 99Tc sources because of their direct similarity to technetium with regard to subsurface mobility, and their large fission yields and low natural background concentrations. We developed an inductively coupled plasma mass spectrometry (ICP-MS) method capable of measuring ruthenium isotopes in groundwater samples and extracts of vadose zone sediments. Samples were analyzed directly on a Perkin Elmer ELAN DRC II ICP-MS after a single pass through a 1-ml bed volume of Dowex AG 50W-X8 100-200 mesh cation exchange resin. Precise ruthenium isotopic ratio measurements were achieved using a low-flow Meinhard-type nebulizer and long sample acquisition times (150,000 ms). Relative standard deviations of triplicate replicates were maintained at less than 0.5% when the total ruthenium solution concentration was 0.1 ng/ml or higher. Further work was performed to minimize the impact caused by mass interferences using the dynamic reaction cell (DRC) with O2 as the reaction gas. The aqueous concentrations of 96Mo and 96Zr were reduced by more than 99.7% in the reaction cell prior to injection of the sample into the mass analyzer quadrupole. The DRC was used in combination with stable-mass correction to quantitatively analyze samples containing up to 2-orders of magnitude more zirconium and molybdenum than ruthenium. The analytical approach documented herein provides an efficient and cost-effective way to precisely measure ruthenium isotopes and quantitate total ruthenium (natural vs. fission-product) in aqueous matrixes.

Brown, Christopher F.; Dresel, P. Evan; Geiszler, Keith N.; Farmer, Orville T.

2006-05-09T23:59:59.000Z

31

The parallel reaction monitoring method contributes to a highly sensitive polyubiquitin chain quantification  

SciTech Connect (OSTI)

Highlights: •The parallel reaction monitoring method was applied to ubiquitin quantification. •The ubiquitin PRM method is highly sensitive even in biological samples. •Using the method, we revealed that Ufd4 assembles the K29-linked ubiquitin chain. -- Abstract: Ubiquitylation is an essential posttranslational protein modification that is implicated in a diverse array of cellular functions. Although cells contain eight structurally distinct types of polyubiquitin chains, detailed function of several chain types including K29-linked chains has remained largely unclear. Current mass spectrometry (MS)-based quantification methods are highly inefficient for low abundant atypical chains, such as K29- and M1-linked chains, in complex mixtures that typically contain highly abundant proteins. In this study, we applied parallel reaction monitoring (PRM), a quantitative, high-resolution MS method, to quantify ubiquitin chains. The ubiquitin PRM method allows us to quantify 100 attomole amounts of all possible ubiquitin chains in cell extracts. Furthermore, we quantified ubiquitylation levels of ubiquitin-proline-?-galactosidase (Ub-P-?gal), a historically known model substrate of the ubiquitin fusion degradation (UFD) pathway. In wild-type cells, Ub-P-?gal is modified with ubiquitin chains consisting of 21% K29- and 78% K48-linked chains. In contrast, K29-linked chains are not detected in UFD4 knockout cells, suggesting that Ufd4 assembles the K29-linked ubiquitin chain(s) on Ub-P-?gal in vivo. Thus, the ubiquitin PRM is a novel, useful, quantitative method for analyzing the highly complicated ubiquitin system.

Tsuchiya, Hikaru; Tanaka, Keiji, E-mail: tanaka-kj@igakuken.or.jp; Saeki, Yasushi, E-mail: saeki-ys@igakuken.or.jp

2013-06-28T23:59:59.000Z

32

Polymerase chain reaction and synthetic DNA probes: a means of distinguishing the causative agents of syphilis and yaws?  

Science Journals Connector (OSTI)

...Polymerase chain reaction and synthetic DNA probes: a means of distinguishing...Bilthoven, The Netherlands. Synthetic DNA probes specific for either the...Polymerase chain reaction and synthetic DNA probes: a means of distinguishing...

G T Noordhoek; B Wieles; J J van der Sluis; J D van Embden

1990-06-01T23:59:59.000Z

33

Improved polymerase chain reaction (PCR) detection ofGaeumannomyces graminis including a safeguard against false negatives  

Science Journals Connector (OSTI)

A previously reported method for polymerase chain reaction (PCR) detection ofGaeumannomyces graminis was modified to simplify it, improve its specificity and decrease the possibility of contamination of the assay...

Elaine Ward

1995-09-01T23:59:59.000Z

34

Gas-phase combustion processes in light of the theory of non-isothermal chain reactions  

Science Journals Connector (OSTI)

The presented experimental and theoretical results demonstrate, in contrast to the concept commonly accepted until recently, the key role of the branching-chain reaction mechanism in gas-phase combustion processes

V. V. Azatyan

2014-02-01T23:59:59.000Z

35

Microscopic theory of protein folding rates. II. Local reaction coordinates and chain dynamics  

E-Print Network [OSTI]

Microscopic theory of protein folding rates. II. Local reaction coordinates and chain dynamics John involved in barrier crossing for protein folding are investigated in terms of the chain dynamics of the polymer backbone, completing the microscopic description of protein folding presented in the preceding

Takada, Shoji

36

First-Hand Recollections of the First Self-Sustaining Chain Reaction |  

Broader source: Energy.gov (indexed) [DOE]

First-Hand Recollections of the First Self-Sustaining Chain First-Hand Recollections of the First Self-Sustaining Chain Reaction First-Hand Recollections of the First Self-Sustaining Chain Reaction August 3, 2012 - 4:53pm Addthis On December 2, 1942, 49 scientists, led by Enrico Fermi, made history when Chicago Pile 1 (CP-1) went critical and produced the world's first self-sustaining, controlled nuclear chain reaction. Seventy years later, two of the last surviving CP-1 pioneers, Harold Agnew and Warren Nyer, recall that historic day. Michael Hess Michael Hess Former Digital Communications Specialist, Office of Public Affairs How were the natives? A small graphite block from the pile is on display at the Museum of Science and Industry in Chicago; another can be seen at the Bradbury Science Museum in Los Alamos, NM.

37

Determination of70Ge(n,p)70Ga and74Ge(n,p)74Ga reaction cross sections for a fission neutron spectrum  

Science Journals Connector (OSTI)

The fission neutron spectrum averaged cross-sections for the reactions70Ge(n,p)70Ga and74Ge(n,p)74Ga have been determined. The averages of four determinations are, respectively, (3.10±0.30) mb and (0.00938±0.0005...

I. M. Cohen; A. J. Kestelman; J. C. Furnari…

1996-03-14T23:59:59.000Z

38

Time scale of the fission process in the reaction 50A MeV 20Ne + 165Ho  

E-Print Network [OSTI]

system of mass 178 amu and excitation energy of 580 MeV that the fission time is [ ] 1 x 10-20 s regardless of the asymmetry....

Mdeiwayeh, Nader

2012-06-07T23:59:59.000Z

39

A string reaction coordinate for the folding of a polymer chain  

E-Print Network [OSTI]

We investigate the crystallization mechanism of a single, flexible homopolymer chain with short range attractions. For a sufficiently narrow attractive well, the system undergoes a first-order like freezing transition from an expanded disordered coil to a compact crystalline state. Based on a maximum likelihood analysis of committor values computed for configurations obtained by Wang-Landau sampling, we construct a non-linear string reaction coordinate for the coil-to-crystal transition. In contrast to a linear reaction coordinate, the string reaction coordinate captures the effect of different degrees of freedom controlling different stages of the transition. Our analysis indicates that a combination of the energy and the global crystallinity parameter Q6 provide the most accurate measure for the progress of the transition. While the crystallinity parameter Q6 is most relevant in the initial stages of the crystallization, the later stages are dominated by a decrease in the potential energy.

Leitold, Christian; Dellago, Christoph

2015-01-01T23:59:59.000Z

40

Measurement of Gastrin and Transforming Growth Factor ? Messenger RNA Levels in Colonic Carcinoma Cell Lines by Quantitative Polymerase Chain Reaction  

Science Journals Connector (OSTI)

...reprints should be addressed. A synthetic DNA template has been constructed...polymerase chain reaction. | A synthetic DNA template has been constructed...3050, Australia ABSTRACT A synthetic DNA template has been constructed...

Graham S. Baldwin and Qun-Xing Zhang

1992-04-15T23:59:59.000Z

Note: This page contains sample records for the topic "fission chain reaction" 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

Microscopic Theory of Protein Folding Rates.II: Local Reaction Coordinates and Chain Dynamics  

E-Print Network [OSTI]

The motion involved in barrier crossing for protein folding are investigated in terms of the chain dynamics of the polymer backbone, completing the microscopic description of protein folding presented in the previous paper. Local reaction coordinates are identified as collective growth modes of the unstable fluctuations about the saddle-points in the free energy surface. The description of the chain dynamics incorporates internal friction (independent of the solvent viscosity) arising from the elementary isomerizations of the backbone dihedral angles. We find that the folding rate depends linearly on the solvent friction for high viscosity, but saturates at low viscosity because of internal friction. For $\\lambda$-repressor, the calculated folding rate prefactor, along with the free energy barrier from the variational theory, gives a folding rate that agrees well with the experimentally determined rate under highly stabilizing conditions, but the theory predicts too large a folding rate at the transition midpoint. This discrepancy obtained using a fairly complete quantitative theory inspires a new set of questions about chain dynamics, specifically detailed motions in individual contact formation.

John J. Portman; Shoji Takada; Peter G. Wolynes

2000-08-30T23:59:59.000Z

42

Diagnosis of human cytomegalovirus-induced retinitis in human immunodeficiency virus type 1-infected subjects by using the polymerase chain reaction.  

Science Journals Connector (OSTI)

...using the polymerase chain reaction. T E Fenner J Garweg F T Hufert M Boehnke H Schmitz...the Polymerase Chain Reaction THOMAS E. FENNER,l JUSTUS GARWEG,2 FRANK T. HUFERT...Clin. N. Am. 2:495-509. 4. Fenner, T., C. Lunkenheimer, F. Hufert...

T E Fenner; J Garweg; F T Hufert; M Boehnke; H Schmitz

1991-11-01T23:59:59.000Z

43

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

44

Low Energy Fission of {sup 256}No, {sup 270}Sg, {sup 271}Hs and {sup 286}112 Nuclei Formed in Reactions with {sup 22}Ne and {sup 48}Ca Ions  

SciTech Connect (OSTI)

The fusion-fission reactions {sup 22}Ne + {sup 248}Cm and {sup 22}Ne + {sup 249}Cf were investigated at projectile energies equal to 102 and 127 MeV. Mass-energy distributions and yields are shown. Two-dimensional plots of TKE vs fragment mass are also shown for {sup 48}Ca reactions at 230 MeV with {sup 208}Pb and {sup 238}U, leading to {sup 256}No and {sup 286}112.

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

1999-12-31T23:59:59.000Z

45

Neutron Emission in Fission And Quasi-Fission of Hs  

SciTech Connect (OSTI)

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

46

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

SciTech Connect (OSTI)

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

47

Measurement of prompt neutron spectra from the 239Pu(n,f) fission reaction for incident neutron energies from 1 to 200 MeV  

Science Journals Connector (OSTI)

Prompt fission neutron spectra in the neutron-induced fission of 239Pu have been measured for incident neutron energies from 1 to 200 MeV at the Los Alamos Neutron Science Center. Mean energies deduced from the prompt fission neutron spectra (PFNS) lead to the observation of the opening of the second chance fission at 7 MeV and to indications for the openings of fission channels of third and fourth chances. Moreover, the general trend of the measured PFNS is well reproduced by the different models. The comparison between data and models presents, however, two discrepancies. First, the prompt neutron mean energy seems constant for neutron energy, at least up to 7 MeV, whereas in the theoretical calculations it is continuously increasing. Second, data disagree with models on the shape of the high energy part of the PFNS, where our data suggest a softer spectrum than the predictions.

A. Chatillon; G. Bélier; T. Granier; B. Laurent; B. Morillon; J. Taieb; R. C. Haight; M. Devlin; R. O. Nelson; S. Noda; J. M. O'Donnell

2014-01-15T23:59:59.000Z

48

Break-up of the Larsen B Ice Shelf Triggered by Chain-Reaction Drainage of Supraglacial Lakes  

E-Print Network [OSTI]

ice-shelf thinning) would continue to reduce the critical lake 200 depth necessary to produce ring-type fractures. In addition, increased basal melting leads 201 to substantial cooling of the ice shelf interior [Sergienko et al., 2013], making... Break-up of the Larsen B Ice Shelf Triggered by Chain-Reaction 1 Drainage of Supraglacial Lakes 2 Alison F. Banwell1,2, Douglas R. MacAyeal1 and Olga V. Sergienko3 3 1The Department of Geophysical Sciences, The University of Chicago, Chicago, IL...

Banwell, Alison F.; MacAyeal, Douglas R.; Sergienko, Olga V.

2014-12-12T23:59:59.000Z

49

MODELING AND FISSION CROSS SECTIONS FOR AMERICIUM.  

SciTech Connect (OSTI)

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

50

Sensitive Detection of Rare Circulating Neuroblastoma Cells by the Reverse Transcriptase-Polymerase Chain Reaction  

Science Journals Connector (OSTI)

...total volume of 50 n\\. One hundred units MMV reverse transcriptase (BRL) were added, and the reaction was allowed to pro ceed at 41 Cfor 1 h. The PCR mixture consisted of 5 n\\ 10 x Taq RT buffer (400 mm KC1, 0.1% gelatin), 5 n\\ 1 HIMdeoxynucleotide...

Leonard A. Mattano, Jr.; Thomas J. Moss; Stephen G. Emerson

1992-09-01T23:59:59.000Z

51

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

52

Event-by-Event Fission with FREYA  

SciTech Connect (OSTI)

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

53

Advanced modeling of prompt fission neutrons  

SciTech Connect (OSTI)

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

54

Coulomb effects in isobaric cold fission from reactions 233U(nth,f), 235U(nth,f), 239Pu(nth,f) and 252Cf(sf)  

E-Print Network [OSTI]

The Coulomb effect hypothesis, formerly used to interpret fluctuations in the curve of maximal total kinetic energy as a function of light fragment mass in reactions 233U(nth,f), 235U(nth,f) and 239Pu(nth,f), is confirmed in high kinetic energy as well as in low excitation energy windows, respectively. Data from reactions 233U(nth,f), 235U(nth,f), 239Pu(nth,f) and 252Cf(sf) show that, between two isobaric fragmentations with similar Q-values, the more asymmetric charge split reaches the higher value of total kinetic energy. Moreover, in isobaric charge splits with different Q-values, similar preference for asymmetrical fragmentations is observed in low excitation energy windows.

Modesto Montoya

2014-03-15T23:59:59.000Z

55

Computerized Pathway Elucidation for Hydroxyl Radical-Induced Chain Reaction Mechanisms in Aqueous Phase Advanced Oxidation Processes  

Science Journals Connector (OSTI)

The reaction network generator consists of three interrelated modules: the reaction pathway generation module, the rate constant estimation module, and the module that generates and solves the ordinary differential equations (ODEs). ... notation system is described for information processing. ... These products are explained by three primary processes (formation of CH3O• + •CH3; CH3OCH2• + •H; and CH2O + CH4), the rearrangement process (CH3O•?•CH2OH) known to be undergone by alkoxyl radicals in aq. ...

Ke Li; John Crittenden

2009-03-10T23:59:59.000Z

56

Fission, Fusion Materials Facility  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

57

Transfer-induced fission of superheavy nuclei  

SciTech Connect (OSTI)

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

58

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

59

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

60

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

Note: This page contains sample records for the topic "fission chain reaction" 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

An analysis of tritium and fissile fuel exchange in fusion-fission systems  

E-Print Network [OSTI]

production reactors, respectively. R denotes the reaction rate, which is the fusion rate for the hybrid fusion reactor and the fissile consumption rate for both types of fission reactors. C expresses the number of atoms produced per reaction and "a... production reactors, respectively. R denotes the reaction rate, which is the fusion rate for the hybrid fusion reactor and the fissile consumption rate for both types of fission reactors. C expresses the number of atoms produced per reaction and "a...

Rice, Brent Lee

2012-06-07T23:59:59.000Z

62

Fission Detection Using the Associated Particle Technique  

SciTech Connect (OSTI)

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

63

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

64

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

SciTech Connect (OSTI)

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

65

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

66

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

SciTech Connect (OSTI)

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

67

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

68

Fission cross section calculations of actinides with EMPIRE code  

SciTech Connect (OSTI)

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

69

The role of chemical reactions in the Chernobyl accident  

SciTech Connect (OSTI)

It is shown that chemical reactions played an essential role in the Chernobyl accident at all of its stages. It is important that the reactor before the explosion was at maximal xenon poisoning, and its reactivity, apparently, was not destroyed by the explosion. The reactivity release due to decay of Xe-235 on the second day after the explosion led to a reactor power of 80-110 MW. Owing to this power, the chemical reactions of reduction of uranium, plutonium, and other metals at a temperature of about 2000 Degree-Sign C occurred in the core. The yield of fission products thus sharply increased. Uranium and other metals flew down in the bottom water communications and rooms. After reduction of the uranium and its separation from the graphite, the chain reaction stopped, the temperature of the core decreased, and the activity yield stopped.

Grishanin, E. I., E-mail: egrishanin@orexovo.net [Russian Research Center Kurchatov Institute (Russian Federation)

2010-12-15T23:59:59.000Z

70

Heavy Element Synthesis Reactions W. Loveland Oregon State University  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

heavy element synthesis reactions and heavy element properties * Hot (E*35-60 MeV) and Cold (E*15 MeV) fusion reactions * Multi-nucleon transfer reactions * Fission * Atomic...

71

Event-by-Event Simulation of Induced Fission  

SciTech Connect (OSTI)

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

72

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

SciTech Connect (OSTI)

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

73

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 (OSTI)

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

74

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

SciTech Connect (OSTI)

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

75

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

76

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

77

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

78

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

79

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

80

Decay Properties of {sup 266}Bh and {sup 262}Db Produced in the {sup 248}Cm+{sup 23}Na Reaction - Further Confirmation of the {sup 278}113 Decay Chain  

SciTech Connect (OSTI)

Decay properties of an isotope {sup 266}Bh and its daughter nucleus {sup 262}Db produced by the {sup 248}Cm({sup 23}Na,5n) reaction were studied by using a gas-filled recoil separator coupled with a position-sensitive semiconductor detector. {sup 266}Bh was clearly identified from the correlation of the known nuclide, {sup 262}Db. The obtained decay properties of {sup 266}Bh and {sup 262}Db are consistent with those observed in the {sup 278}113 chain by RIKEN collaboration, which provided further confirmation of the discovery of {sup 278}113.

Morita, K.; Morimoto, K.; Kaji, D.; Haba, H.; Ozeki, K.; Kudou, Y.; Yoneda, A.; Ichikawa, T.; Katori, K.; Yoshida, A. [RIKEN Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan); Sato, N. [RIKEN Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan); Department of Physics, Tohoku University, Aoba-ku, Sendai 980-8578 (Japan); Sumita, T. [RIKEN Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan); Faculty of Science and Technology, Tokyo University of Science, Noda, Chiba 278-8510 (Japan); Fujimori, Y.; Tokanai, F. [Department of Physics, Yamagata University, Yamagata 990-8560 (Japan); Goto, S. [Center for Instrumental Analysis, Niigata University, Ikarashi, Nishi-ku, Niigata 950-2181 (Japan); Ideguchi, E. [Center for Nuclear Study, University of Tokyo, Wako, Saitama 351-0198 (Japan); Kasamatsu, Y.; Koura, H.; Tsukada, K. [Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Komori, Y. [Department of Chemistry, Osaka University, Toyonaka, Osaka 560-0043 (Japan)

2010-06-01T23:59:59.000Z

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81

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

82

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

SciTech Connect (OSTI)

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

83

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...

84

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

85

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

86

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

87

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

88

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

89

Neutronics for critical fission reactors and subcritical fission in hybrids  

SciTech Connect (OSTI)

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

90

Multiple-Coincidence Interrogation of Fissionables  

SciTech Connect (OSTI)

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

91

He-jet system to study short-lived fission-product nuclei at LAMPF  

SciTech Connect (OSTI)

Experiments have been performed at LAMPF which demonstrate the feasibility of utilizing a He-jet system to transport fission products to an on-line mass separator from a target chamber mounted in the 800-MeV, >600..mu..A main proton beam. Activities of essentially all elements produced are transported with about 60% absolute efficiency, both for fission reactions and spallation reactions. Transport times are short enough to allow study of activities with half-lives as short as 300 ms. Technical features and scientific possibilities of the system are presented.

Talbert, W.L. Jr.; Bunker, M.E.; Starner, J.W.

1983-01-01T23:59:59.000Z

92

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

93

Status of fission yield evaluations  

SciTech Connect (OSTI)

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

94

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

SciTech Connect (OSTI)

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

95

Prompt {gamma}-ray spectroscopy of isotopically identified fission fragments  

SciTech Connect (OSTI)

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

96

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

97

Triggered amplification by hybridization chain reaction  

E-Print Network [OSTI]

­23) driven by the free energy of base pair formation. Synthetic DNA machines can be powered by strand

Pierce, Niles A.

98

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

99

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

100

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

Note: This page contains sample records for the topic "fission chain reaction" 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.
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101

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

102

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

103

Sleeve reaction chamber system  

DOE Patents [OSTI]

A chemical reaction chamber system that combines devices such as doped polysilicon for heating, bulk silicon for convective cooling, and thermoelectric (TE) coolers to augment the heating and cooling rates of the reaction chamber or chambers. In addition the system includes non-silicon-based reaction chambers such as any high thermal conductivity material used in combination with a thermoelectric cooling mechanism (i.e., Peltier device). The heat contained in the thermally conductive part of the system can be used/reused to heat the device, thereby conserving energy and expediting the heating/cooling rates. The system combines a micromachined silicon reaction chamber, for example, with an additional module/device for augmented heating/cooling using the Peltier effect. This additional module is particularly useful in extreme environments (very hot or extremely cold) where augmented heating/cooling would be useful to speed up the thermal cycling rates. The chemical reaction chamber system has various applications for synthesis or processing of organic, inorganic, or biochemical reactions, including the polymerase chain reaction (PCR) and/or other DNA reactions, such as the ligase chain reaction.

Northrup, M. Allen (Berkeley, CA); Beeman, Barton V. (San Mateo, CA); Benett, William J. (Livermore, CA); Hadley, Dean R. (Manteca, CA); Landre, Phoebe (Livermore, CA); Lehew, Stacy L. (Livermore, CA); Krulevitch, Peter A. (Pleasanton, CA)

2009-08-25T23:59:59.000Z

104

Ph.D. Theses 1. M. Dasgupta Study of cross section and average angular momenta in fusion reactions of 28  

E-Print Network [OSTI]

-fission reactions (BARC, 1994) 7. S. Chattopadhyay Investigation of nuclear structure at high spins in mass-80) 12. A.K. Pandey Studies on the fission properties of low Z elements by solid state nuclear track in 32 to 55 MeV excitation energy region on 28 Si (BARC, 1995) 14. B.J. Roy Reaction Mechanism in heavy

Shyamasundar, R.K.

105

Fission-energy release for 16 fissioning nuclides. Final report  

SciTech Connect (OSTI)

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

106

AFC-1 Fuel Rodlet Fission Power Deposition Validation in ATR  

SciTech Connect (OSTI)

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

107

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

SciTech Connect (OSTI)

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

108

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

109

Modeling Fission Product Sorption in Graphite Structures  

SciTech Connect (OSTI)

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

110

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

111

Theoretical descriptions of neutron emission in fission  

SciTech Connect (OSTI)

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

112

Synthesis of the isotopes of elements 118 and 116 in the 249Cf and 245Cm+48Ca fusion reactions  

SciTech Connect (OSTI)

The decay properties of {sup 290}116 and {sup 291}116, and the dependence of their production cross sections on the excitation energies of the compound nucleus, {sup 293}116, have been measured in the {sup 245}Cm({sup 48}Ca,xn){sup 293-x}116 reaction. These isotopes of element 116 are the decay daughters of element 118 isotopes, which are produced via the {sup 249}Cf+{sup 48}Ca reaction. They performed the element 118 experiment at two projectile energies, corresponding to {sup 297}118 compound nucleus excitation energies of E* = 29.2 {+-} 2.5 and 34.4 {+-} 2.3 MeV. During an irradiation with a total beam dose of 4.1 x 10{sup 19} {sup 48}Ca projectiles, three similar decay chains consisting of two or three consecutive {alpha} decays and terminated by a spontaneous fission (SF) with high total kinetic energy of about 230 MeV were observed. The three decay chains originated from the even-even isotope {sup 294}118 (E{sub {alpha}} = 11.65 {+-} 0.06 MeV, T{sub {alpha}} = 0.89{sub -0.31}{sup +1.07} ms) produced in the 3n-evaporation channel of the {sup 249}Cf+{sup 48}Ca reaction with a maximum cross section of 0.5{sub -0.3}{sup +1.6} pb.

Oganessian, Y T; Utyonkov, V K; Lobanov, Y V; Abdullin, F S; Polyakov, A N; Sagaidak, R N; Shirokovsky, I V; Tsyganov, Y S; Voinov, A A; Gulbekian, G G; Bogomolov, S L; Gikal, B N; Mezentsev, A N; Iliev, S; Subbotin, V G; Sukhov, A M; Subotic, K; Zagrebaev, V I; Vostokin, G K; Itkis, M G; Moody, K J; . Patin, J B; Shaughnessy, D A; Stoyer, M A; Stoyer, N J; Wilk, P A; Kenneally, J M; Landrum, J H; Wild, J F; Lougheed, R W

2006-01-31T23:59:59.000Z

113

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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....

114

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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....

115

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

116

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.

117

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

118

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

119

Spectroscopy of element 115 decay chains  

SciTech Connect (OSTI)

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

120

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

Note: This page contains sample records for the topic "fission chain reaction" 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.


121

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

122

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

123

Italian hybrid and fission reactors scenario analysis  

SciTech Connect (OSTI)

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

124

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

125

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

126

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

SciTech Connect (OSTI)

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

127

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

128

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

129

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

130

Synthesis of the isotopes of elements 118 and 116 in the {sup 249}Cf and {sup 245}Cm+{sup 48}Ca fusion reactions  

SciTech Connect (OSTI)

The decay properties of {sup 290}116 and {sup 291}116, and the dependence of their production cross sections on the excitation energies of the compound nucleus, {sup 293}116, have been measured in the {sup 245}Cm ({sup 48}Ca, xn){sup 293-x}116 reaction. These isotopes of element 116 are the decay daughters of element 118 isotopes, which are produced via the {sup 249}Cf+{sup 48}Ca reaction. We performed the element 118 experiment at two projectile energies, corresponding to {sup 297}118 compound nucleus excitation energies of E*=29.2{+-}2.5 and 34.4{+-}2.3 MeV. During an irradiation with a total beam dose of 4.1x10{sup 19} {sup 48}Ca projectiles, three similar decay chains consisting of two or three consecutive {alpha} decays and terminated by a spontaneous fission (SF) with high total kinetic energy of about 230 MeV were observed. The three decay chains originated from the even-even isotope {sup 294}118 (E{sub {alpha}}=11.65{+-}0.06 MeV, T{sub {alpha}}=0.89{sub -0.31}{sup +1.07} ms) produced in the 3n-evaporation channel of the {sup 249}Cf+{sup 48}Ca reaction with a maximum cross section of 0.5{sub -0.3}{sup +1.6} pb.

Oganessian, Yu. Ts.; Utyonkov, V. K.; Lobanov, Yu. V.; Abdullin, F. Sh.; Polyakov, A. N.; Sagaidak, R. N.; Shirokovsky, I. V.; Tsyganov, Yu. S.; Voinov, A. A.; Gulbekian, G. G.; Bogomolov, S. L.; Gikal, B. N.; Mezentsev, A. N.; Iliev, S.; Subbotin, V. G.; Sukhov, A. M.; Subotic, K.; Zagrebaev, V. I.; Vostokin, G. K.; Itkis, M. G. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); University of California, Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)] (and others)

2006-10-15T23:59:59.000Z

131

Silicon-based sleeve devices for chemical reactions  

DOE Patents [OSTI]

A silicon-based sleeve type chemical reaction chamber that combines heaters, such as doped polysilicon for heating, and bulk silicon for convection cooling. The reaction chamber combines a critical ratio of silicon and silicon nitride to the volume of material to be heated (e.g., a liquid) in order to provide uniform heating, yet low power requirements. The reaction chamber will also allow the introduction of a secondary tube (e.g., plastic) into the reaction sleeve that contains the reaction mixture thereby alleviating any potential materials incompatibility issues. The reaction chamber may be utilized in any chemical reaction system for synthesis or processing of organic, inorganic, or biochemical reactions, such as the polymerase chain reaction (PCR) and/or other DNA reactions, such as the ligase chain reaction, which are examples of a synthetic, thermal-cycling-based reaction. The reaction chamber may also be used in synthesis instruments, particularly those for DNA amplification and synthesis.

Northrup, M. Allen (Berkeley, CA); Mariella, Jr., Raymond P. (Danville, CA); Carrano, Anthony V. (Livermore, CA); Balch, Joseph W. (Livermore, CA)

1996-01-01T23:59:59.000Z

132

Low-Energy Fusion-Fission Dynamics of Heavy Nuclear Systems  

SciTech Connect (OSTI)

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

133

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

134

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

135

Time dependent particle emission from fission products  

SciTech Connect (OSTI)

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

136

Reaction kinetics in living systems  

Science Journals Connector (OSTI)

...l/vi) behaves like a resistance in an electric circuit, and vi itself acts...velocity and the velocity for each elementary step in a chain of reactions...where R is the specific resistance, c is the capacity, 4 g9n...

H Eyring; S M Ma; I Ueda

1981-01-01T23:59:59.000Z

137

A fission-fusion hybrid reactor in steady-state L-mode tokamak configuration with natural uranium  

SciTech Connect (OSTI)

This work develops a conceptual design for a fusion-fission hybrid reactor operating in steady-state L-mode tokamak configuration with a subcritical natural or depleted uranium pebble bed blanket. A liquid lithium-lead alloy breeds enough tritium to replenish that consumed by the D-T fusion reaction. The fission blanket augments the fusion power such that the fusion core itself need not have a high power gain, thus allowing for fully non-inductive (steady-state) low confinement mode (L-mode) operation at relatively small physical dimensions. A neutron transport Monte Carlo code models the natural uranium fission blanket. Maximizing the fission power gain while breeding sufficient tritium allows for the selection of an optimal set of blanket parameters, which yields a maximum prudent fission power gain of approximately 7. A 0-D tokamak model suffices to analyze approximate tokamak operating conditions. This fission blanket would allow the fusion component of a hybrid reactor with the same dimensions as ITER to operate in steady-state L-mode very comfortably with a fusion power gain of 6.7 and a thermal fusion power of 2.1 GW. Taking this further can determine the approximate minimum scale for a steady-state L-mode tokamak hybrid reactor, which is a major radius of 5.2 m and an aspect ratio of 2.8. This minimum scale device operates barely within the steady-state L-mode realm with a thermal fusion power of 1.7 GW. Basic thermal hydraulic analysis demonstrates that pressurized helium could cool the pebble bed fission blanket with a flow rate below 10 m/s. The Brayton cycle thermal efficiency is 41%. This reactor, dubbed the Steady-state L-mode non-Enriched Uranium Tokamak Hybrid (SLEUTH), with its very fast neutron spectrum, could be superior to pure fission reactors in terms of breeding fissile fuel and transmuting deleterious fission products. It would likely function best as a prolific plutonium breeder, and the plutonium it produces could actually be more proliferation-resistant than that bred by conventional fast reactors. Furthermore, it can maintain constant total hybrid power output as burnup proceeds by varying the neutron source strength.

Reed, Mark; Parker, Ronald R.; Forget, Benoit [Department of Nuclear Science and Engineering, Massachusetts Institute of Technology 77 Massachusetts Avenue, Cambridge, MA 02139 (United States)

2012-06-19T23:59:59.000Z

138

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

SciTech Connect (OSTI)

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

139

Polypeptide chain collapse and protein folding Jayant B. Udgaonkar  

E-Print Network [OSTI]

Review Polypeptide chain collapse and protein folding Jayant B. Udgaonkar National Centre is an integral component of a protein folding reaction. In this review, exper- imental characterization solvent [2]. A distinctive physical feature of any protein folding reaction is the greater than 3-fold

140

Microfabricated sleeve devices for chemical reactions  

DOE Patents [OSTI]

A silicon-based sleeve type chemical reaction chamber that combines heaters, such as doped polysilicon for heating, and bulk silicon for convection cooling. The reaction chamber combines a critical ratio of silicon and non-silicon based materials to provide the thermal properties desired. For example, the chamber may combine a critical ratio of silicon and silicon nitride to the volume of material to be heated (e.g., a liquid) in order to provide uniform heating, yet low power requirements. The reaction chamber will also allow the introduction of a secondary tube (e.g., plastic) into the reaction sleeve that contains the reaction mixture thereby alleviating any potential materials incompatibility issues. The reaction chamber may be utilized in any chemical reaction system for synthesis or processing of organic, inorganic, or biochemical reactions, such as the polymerase chain reaction (PCR) and/or other DNA reactions, such as the ligase chain reaction, which are examples of a synthetic, thermal-cycling-based reaction. The reaction chamber may also be used in synthesis instruments, particularly those for DNA amplification and synthesis.

Northrup, M. Allen (Berkeley, CA)

2003-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "fission chain reaction" 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

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

142

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

143

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...

144

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...

145

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.;...

146

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

147

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

148

Direct reactions for nuclear structure and nuclear astrophysics  

SciTech Connect (OSTI)

Direct reactions are powerful probes for studying the atomic nucleus. Modern direct reaction studies are illuminating both the fundamental nature of the nucleus and its role in nucleosynthetic processes occurring in the cosmos. This report covers experiments using knockout reactions on neutron-deficient fragmentation beams, transfer reactions on fission fragment beams, and theoretical sensitivity studies relating to the astrophysical r-process. Results from experiments on 108,106Sn at the NSCL, and on 131Sn at HRIBF are presented as well as the results from the nucleosynthesis study.

Jones, Katherine Louise [University of Tennessee] (ORCID:0000000173351379)

2014-12-18T23:59:59.000Z

149

Predicting the production of neutron rich heavy nuclei in multi-nucleon transfer reactions using GRAZING-F  

E-Print Network [OSTI]

Background: Multi-nucleon transfer reactions have recently attracted attention as a possible path to the synthesis of new neutron-rich heavy nuclei. Purpose: We study transfer reactions involving massive nuclei with the intention of understanding if the semi-classical model GRAZING coupled to an evaporation and fission competition model can satisfactory reproduce experimental data on transfer reactions in which fission plays a role. Methods: We have taken the computer code GRAZING and have added fission competition to it (GRAZING-F) using our current understanding of $\\Gamma_n/\\Gamma_f$, fission barriers and level densities. Results: The code GRAZING-F seems to satisfactory reproduce experimental data for $+1p$, $+2p$ and $+3p$ transfers, but has limitations in reproducing measurements of larger above-target and below-target transfers. Nonetheless, we use GRAZING-F to estimate production rates of neutron-rich $N=126$ nuclei, actinides and transactinides. Conclusions: The GRAZING code, with appropriate modific...

Yanez, R

2015-01-01T23:59:59.000Z

150

Fission neutron spectra measurements at LANSCE - status and plans  

SciTech Connect (OSTI)

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

151

Feasibility study of a fission-suppressed tokamak fusion breeder  

SciTech Connect (OSTI)

The preliminary conceptual design of a tokamak fissile fuel producer is described. The blanket technology is based on the fission suppressed breeding concept where neutron multiplication occurs in a bed of 2 cm diameter beryllium pebbles which are cooled by helium at 50 atmospheres pressure. Uranium-233 is bred in thorium metal fuel elements which are in the form of snap rings attached to each beryllium pebble. Tritium is bred in lithium bearing material contained in tubes immersed in the pebble bed and is recovered by a purge flow of helium. The neutron wall load is 3 MW/m/sup 2/ and the blanket material is ferritic steel. The net fissile breeding ratio is 0.54 +- 30% per fusion reaction. This results in the production of 4900 kg of /sup 233/U per year from 3000 MW of fusion power. This quantity of fuel will provide makeup fuel for about 12 LWRs of equal thermal power or about 18 1 GW/sub e/ LWRs. The calculated cost of the produced uranium-233 is between $23/g and $53/g or equivalent to $10/kg to $90/kg of U/sub 3/O/sub 8/ depending on government financing or utility financing assumptions. Additional topics discussed in the report include the tokamak operating mode (both steady state and long pulse considered), the design and breeding implications of using a poloidal divertor for impurity control, reactor safety, the choice of a tritium breeder, and fuel management.

Moir, R.W.; Lee, J.D.; Neef, W.S.; Berwald, D.H.; Garner, J.K.; Whitley, R.H.; Ghoniem, N.; Wong, C.P.C.; Maya, I.; Schultz, K.R.

1984-12-01T23:59:59.000Z

152

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

153

Chemical factors affecting fission product transport in severe LMFBR accidents  

SciTech Connect (OSTI)

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

154

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

155

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

156

A Fission-Powered Interstellar Precursor Mission  

SciTech Connect (OSTI)

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

157

Ceramic Hosts for Fission Products Immobilization  

SciTech Connect (OSTI)

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

158

Multiple-Coincidence Active Neutron Interrogation of Fissionable Materials  

SciTech Connect (OSTI)

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

159

Improved Fission Neutron Data Base for Active Interrogation of Actinides  

SciTech Connect (OSTI)

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

160

Fission product studies in the symmetric mass region  

SciTech Connect (OSTI)

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

Note: This page contains sample records for the topic "fission chain reaction" 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
to obtain the most current and comprehensive results.


161

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

162

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

163

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

SciTech Connect (OSTI)

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

164

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 (OSTI)

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

165

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

166

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

167

(Fuel, fission product, and graphite technology)  

SciTech Connect (OSTI)

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

168

Compilation of fission product yields Vallecitos Nuclear Center  

SciTech Connect (OSTI)

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

169

Discovery of a new mode of nuclear fission  

SciTech Connect (OSTI)

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

170

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

171

Actinide neutron-induced fission cross section measurements at LANSCE  

SciTech Connect (OSTI)

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

172

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

SciTech Connect (OSTI)

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

173

Actinide Neutron-Induced Fission Cross Section Measurements At LANSCE  

SciTech Connect (OSTI)

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

174

Partition of actinides and fission products between metal and molten salt phases: Theory, measurement, and application to IFR pyroprocess development  

SciTech Connect (OSTI)

The chemical basis of Integral Fast Reactor fuel reprocessing (pyroprocessing) is partition of fuel, cladding, and fission product elements between molten LiCl-KCl and either a solid metal phase or a liquid cadmium phase. The partition reactions are described herein, and the thermodynamic basis for predicting distributions of actinides and fission products in the pyroprocess is discussed. The critical role of metal-phase activity coefficients, especially those of rare earth and the transuranic elements, is described. Measured separation factors, which are analogous to equilibrium constants but which involve concentrations rather than activities, are presented. The uses of thermodynamic calculations in process development are described, as are computer codes developed for calculating material flows and phase compositions in pyroprocessing.

Ackerman, J.P.; Johnson, T.R.

1993-10-01T23:59:59.000Z

175

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

SciTech Connect (OSTI)

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

176

110101BenefitsNuclearFission.ppt [Read-Only]  

Broader source: Energy.gov (indexed) [DOE]

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

177

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

178

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

179

Half life for spontaneous fission of curium-245  

SciTech Connect (OSTI)

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

180

Thermodynamics of fission products in UO2+-x  

SciTech Connect (OSTI)

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

Note: This page contains sample records for the topic "fission chain reaction" 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.


181

Identification of Fissionable Materials Using the Tagged Neutron Technique  

SciTech Connect (OSTI)

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

182

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...

183

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...

184

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

185

Spontaneous fission half-lives for ground state nuclides  

SciTech Connect (OSTI)

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

186

In-cell reaction rate distributions and cell-average reaction rates in fast critical assemblies  

SciTech Connect (OSTI)

Measurements are described for determining average values of fission rates in /sup 235/U, /sup 238/U and /sup 239/Pu and capture rates in /sup 238/U for heterogeneous cells used to construct fast critical assemblies. The measurements are based on irradiations of foils of /sup 238/U, /sup 235/U and /sup 239/Pu with counting of fission and capture products using gamma-ray spectroscopy. Both plate and pin cells are considered. Procedures are described for inferring cell-average reaction rate values from a single foil location based on a cell using a quantity called a cell factor. Cell factors are determined from special measurements in which several foils are irradiated within a cell. Comparisons are presented between cell factors determined by measurements and by Monte Carlo calculations which lend credibility to the measurement procedures.

Brumbach, S.B.; Gasidlo, J.M.

1985-08-01T23:59:59.000Z

187

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

SciTech Connect (OSTI)

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

188

Calculation of Fission Observables Through Event-by-Event Simulation  

SciTech Connect (OSTI)

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

189

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

SciTech Connect (OSTI)

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

190

Non-equilibrium fission processes in intermediate energy nuclear collisions  

SciTech Connect (OSTI)

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

191

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

SciTech Connect (OSTI)

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

192

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.

193

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.

194

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

195

PoS(NIC-IX)040 Direct reactions in/for astrophysics  

E-Print Network [OSTI]

on the opposite ends of the energy scale of nuclear reactions: (a) the very high and (b) the very low relative scale are the low energy reactions of importance for stellar evolution. Chains of nuclear reactions lead reactions methods have been developed and applied to extract low-energy astrophysical S

Bertulani, Carlos A. - Department of Physics and Astronomy, Texas A&M University

196

Mechanisms of lead release from uraninite in the natural fission reactors in Gabon  

SciTech Connect (OSTI)

Twenty-four samples of uranium ore from the natural fission reactors in Gabon were studied by detailed electron microprobe analysis and backscattered electron imaging in order to determine the behavior of radiogenic Pb and fissiongenic nuclides. Lead content in uraninite varies from 19 wt% PbO in relicts of pristine uraninite, which were found only in reactor zone 10, to less than 5 wt% in altered uraninites. Different mechanisms of Pb loss from uraninite prevailed in different reactor zones and included leaching, grain boundary diffusion, exsolution via continuous precipitation, and volume diffusion. As a result of these processes, Pb content in uraninites from all the reactor zones, except for reactor zone 10, are similar and vary around a mean value of 5.2 wt% PbO. All of these processes were thermally activated and episodic. The predominance of any single mechanism in a particular reactor zone was controlled by the accessibility of solutions to the uranium ore. The thermal event which caused Pb mobilization in the deposits resulted from regional igneous activity in the Franceville Basin more than 1100 Ma after the reactors sustained spontaneous fission reactions. Reducing conditions prevented the long distance migration of Pb, as well as of fissiongenic Mo and Ru.

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

1995-05-01T23:59:59.000Z

197

Synthesis of Main-Chain Polyoxometalate-Containing Hybrid Polymers and Their Applications in Photovoltaic Cells  

Science Journals Connector (OSTI)

Hexamolybdate clusters have been embedded through covalent bonds into the main chain of poly(phenylene acetylene)s. These hybrid polymers were synthesized by palladium-catalyzed coupling reactions of a diiodo functionalized cluster with a diethynylbenzene ...

Meng Lu; Baohan Xie; Jeonghee Kang; Fang-Chung Chen; Yang Yang; Zhonghua Peng

2004-12-29T23:59:59.000Z

198

The Future of Energy from Nuclear Fission  

SciTech Connect (OSTI)

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

199

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

200

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

Note: This page contains sample records for the topic "fission chain reaction" 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

Modeling of Fission Gas Release in UO2  

SciTech Connect (OSTI)

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

202

Initial Back-to-Back Fission Chamber Testing in ATRC  

SciTech Connect (OSTI)

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

203

Dynamical simulation of energy dissipation in asymmetric heavy-ion induced fission of Pb200, Fr213, and Es251  

Science Journals Connector (OSTI)

The dynamical model based on the asymmetric mass division has been applied to calculate pre-scission neutron multiplicity from heavy-ion induced fusion-fission reactions. Links between the pre-scission neutron multiplicity, excitation energy, and asymmetric mass distribution are clarified based on the Monte Carlo simulation and Langevin dynamics. The pre-scission neutron multiplicity is calculated and compared with the respective experimental data over a wide range of excitation energy and nonconstant viscosity. The analysis indicates a different effect for the application of asymmetric mass division in different energy regions of such processes.

S. M. Mirfathi and M. R. Pahlavani

2008-12-29T23:59:59.000Z

204

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

SciTech Connect (OSTI)

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

205

Toward Designed Singlet Fission: Electronic States and Photophysics of  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

206

Fission cross section measurements of actinides at LANSCE  

SciTech Connect (OSTI)

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

207

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

208

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

209

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

210

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

211

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

212

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

213

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

Broader source: Energy.gov (indexed) [DOE]

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...

214

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

215

Singlet fission efficiency in tetracene-based organic solar cells  

SciTech Connect (OSTI)

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

216

Cross section for {sup 246}Cm subbarrier fission  

SciTech Connect (OSTI)

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

217

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

218

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

219

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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

220

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

Note: This page contains sample records for the topic "fission chain reaction" 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

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

SciTech Connect (OSTI)

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

222

Spallation-Fission Competition in Heaviest Elements; Helium Ion Induced Reactions in Plutonium Isotopes  

E-Print Network [OSTI]

James W. Cobble, and Glenn T. Seaborg Radiation LaboratoryJames W. Cobble, and Glenn T. Seaborg Radiation Laboratory

Glass, Richard A.; Carr, Robert J.; Cobble, James W.; Seaborg, Glenn T.

1956-01-01T23:59:59.000Z

223

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

224

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

225

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

226

Fission-suppressed hybrid reactor: the fusion breeder  

SciTech Connect (OSTI)

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

227

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

228

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...

229

Wittig Reaction 33 Reaction: Synthesis of Alkenes  

E-Print Network [OSTI]

" an "ylide" Cl R3 R R3 OR2 Ph3P R1 H R2 R1 R Br R1 H R PPh3 SN2 Phosphonium Salt Aldehyde or Ketone AlkeneWittig Reaction 33 The Wittig Reaction: Synthesis of Alkenes Intro The "Wittig Reaction" is one elimination reactions (E1 or E2 reactions from alcohols or alkyl halides, for example), in elimination

Jasperse, Craig P.

230

Nuclear Design of the HOMER-15 Mars Surface Fission Reactor  

SciTech Connect (OSTI)

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

231

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

232

Theoretical Studies on the CH3CO + Cl Reaction: Hydrogen Abstraction versus CO Displacement  

E-Print Network [OSTI]

potential energy surface reveals this reaction to be a capture-limited association-elimination reaction the efficiency of a chain reaction. Recently Maricq et al.1 reported the real-time kinetic mea- surements for one earlier potential energy surface,3 is also consistent with an addition-elimination mechanism since

Nguyen, Minh Tho

233

arXiv:nucl-th/0607015v213Jul2006 Direct reactions in/for astrophysics  

E-Print Network [OSTI]

. In recent years direct reactions methods have been developed and applied to extract low-energy astrophysical are focused on the opposite ends of the energy scale of nuclear reactions: (a) the very high and (b) the very end of the energy scale are the low energy reactions of importance for stellar evolution. Chains

Bertulani, Carlos A. - Department of Physics and Astronomy, Texas A&M University

234

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

235

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

SciTech Connect (OSTI)

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

236

Tetramethyl-1-silacycloprop-2-ene: its characterization and reactions  

SciTech Connect (OSTI)

The object of this research is to fully characterize and study some of the reactions of tetramethyl-1-silacycloprop-2-ene. The final characterization of this compound was accomplished by obtaining both Si29 and 13C nuclear magnetic resonance spectra. The reactions studied included those with fluorenone, acetone, styrene, phenylacetylene, acetonitrile, t-butylcyanide, methyl isocyanate, phenyl azide, and azobenzene. Product analyses suggest that aside from addition reactions tetramethylsilacyclopropene can react either via a radical chain polymerization or an anionic chain polymerization mechanism with the latter being the more prevalent. Other reactions studied included the photolysis of tetramethylsilacyclopropene and its reactions in the presence of Pd(PPh/sub 3/)/sub 2/Cl/sub 2/. An appendix includes a study of trimethylsilyl radical disproportionation in the liquid phase to a sila olefin. Trimethylsilyl radicals in solution undergo disproportionation as well as recombination in a 1:5 ratio. The sila olefin formed by disproportionation was trapped by alcohols.

Cornett, B.J.

1980-05-01T23:59:59.000Z

237

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 (OSTI)

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

238

Fusion-Fission Hybrid for Fissile Fuel Production without Processing  

SciTech Connect (OSTI)

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

239

High-precision prompt-?-ray spectral data from the reaction Pu241(nth, f)  

Science Journals Connector (OSTI)

In this paper we present results from the first high-precision prompt-?-ray spectral measurements from the reaction Pu241(nth, f). Apart from one recent experiment, no data are reported in the literature for this fissioning system, which motivated a new dedicated experiment. We have measured prompt-fission ? rays with three cerium-doped LaBr3 (two 5.08cm×5.08 cm and one 7.62cm×7.62 cm) and one CeBr3 (5.08cm×5.08 cm) scintillation detectors, which all exhibit excellent timing and good energy resolution. The average ?-ray multiplicity was determined to be ?¯?=(8.21±0.09) per fission, the average energy to be ??=(0.78±0.01) MeV, and the total energy to be E?,tot=(6.41±0.06) MeV as the weighted average from all detectors. Since the results from all detectors are in excellent agreement, and the total released ? energy is modestly higher than the one in the present evaluated nuclear data files, we suspect that the underestimation of the prompt-? heating in nuclear reactors is due to fast-neutron-induced fission on U238 or rather from fission induced by ? rays from neutron capture in the construction material.

S. Oberstedt; R. Billnert; T. Belgya; T. Bry?; W. Geerts; C. Guerrero; F.-J. Hambsch; Z. Kis; A. Moens; A. Oberstedt; G. Sibbens; L. Szentmiklosi; D. Vanleeuw; M. Vidali

2014-08-26T23:59:59.000Z

240

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)

Note: This page contains sample records for the topic "fission chain reaction" 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

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

242

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

243

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.

244

On Thermonuclear Reaction Rates  

E-Print Network [OSTI]

Nuclear reactions govern major aspects of the chemical evolution od galaxies and stars. Analytic study of the reaction rates and reaction probability integrals is attempted here. Exact expressions for the reaction rates and reaction probability integrals for nuclear reactions in the case of nonresonant, modified nonresonant, screened nonresonant and resonant cases are given. These are expressed in terms of H-functions, G-functions and in computable series forms. Computational aspects are also discussed.

H. J. Haubold; A. M. Mathai

1996-12-02T23:59:59.000Z

245

(Fission product transport experiments (HFR-B1))  

SciTech Connect (OSTI)

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

246

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

247

Behavior of the Cross Sections for Polonium Production in Nuclear Reactions of Ar40 with Dy104  

Science Journals Connector (OSTI)

Excitation functions are reported for the reactions of Dy164 with Ar40 to produce Po200 and Po199. The cross sections are much smaller than the calculated values and it is concluded that this is due to an angular momentum cutoff and to a large fission width. The reaction threshold at a laboratory energy of 4.2 MeV per nucleon indicates a low Coulomb barrier (r0=1.45 fm).

Y. Le Beyec; M. Lefort; A. Vigny

1971-03-01T23:59:59.000Z

248

Extracorporeal membrane oxygenation promotes long chain fatty...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

249

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

250

Microstructural Characterization of Irradiated U-7Mo/Al-5Si Dispersion to High Fission Density  

SciTech Connect (OSTI)

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

251

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

252

Experimental Measurements of Short-Lived Fission Products from Uranium, Neptunium, Plutonium and Americium  

SciTech Connect (OSTI)

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

253

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

254

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

SciTech Connect (OSTI)

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

255

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

256

E-Print Network 3.0 - alpha -particle fission Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

257

Microsoft Word - illinois_reactors_taiwo.doc  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

258

Theory of nuclear reactions  

SciTech Connect (OSTI)

The book presents a theory of nuclear reaction. An account is given of the nonrelativistic nuclear reaction theory. The R - matrix description of nuclear reactions is considered and the dispersion method is formulated. Mechanisms of nuclear reactions and their relationship are studied in detail. Attention is paid to nuclear reactions involving the compound nuclear formation and to direct nuclear processes. The optical model the diffraction approach and high - energy diffraction nuclear processes involving composite particles are discussed.

Sitenko, A.G.

1990-01-01T23:59:59.000Z

259

Measurements of cross sections and decay properties of the isotopes of elements 112, 114, and 116 produced in the fusion reactions {sup 233,238}U, {sup 242}Pu, and {sup 248}Cm+{sup 48}Ca  

SciTech Connect (OSTI)

We have studied the dependence of the production cross sections of the isotopes {sup 282,283}112 and {sup 286,287}114 on the excitation energy of the compound nuclei {sup 286}112 and {sup 290}114. The maximum cross section values of the xn-evaporation channels for the reaction {sup 238}U({sup 48}Ca,xn){sup 286-x}112 were measured to be {sigma}{sub 3n}=2.5{sub -1.1}{sup +1.8} pb and {sigma}{sub 4n}=0.6{sub -0.5}{sup +1.6} pb; for the reaction {sup 242}Pu({sup 48}Ca,xn){sup 290-x}114: {sigma}{sub 2n}{approx}0.5 pb, {sigma}{sub 3n}=3.6{sub -1.7}{sup +3.4} pb, and {sigma}{sub 4n}=4.5{sub -1.9}{sup +3.6} pb. In the reaction {sup 233}U({sup 48}Ca,2-4n){sup 277-279}112 at E*=34.9=2.2 MeV we measured an upper cross section limit of {sigma}{sub xn}{<=}0.6 pb. The observed shift of the excitation energy associated with the maximum sum evaporation residue cross section {sigma}{sub ER}(E*) to values significantly higher than that associated with the calculated Coulomb barrier can be caused by the orientation of the deformed target nucleus in the entrance channel of the reaction. An increase of {sigma}{sub ER} in the reactions of actinide targets with {sup 48}Ca is consistent with the expected increase of the survivability of the excited compound nucleus upon closer approach to the closed neutron shell N=184. In the present work we detected 33 decay chains arising in the decay of the known nuclei {sup 282}112, {sup 283}112, {sup 286}114, {sup 287}114, and {sup 288}114. In the decay of {sup 287}114({alpha}){yields}{sup 283}112({alpha}){yields}{sup 279}110(SF), in two cases out of 22, we observed decay chains of four and five sequential {alpha} transitions that end in spontaneous fission of {sup 271}Sg (T{sub {alpha}}{sub /SF}=2.4{sub -1.0}{sup +4.3} min) and {sup 267}Rf (T{sub SF}{approx}2.3 h), longer decay chains than reported previously. We observed the new nuclide {sup 292}116 (T{sub {alpha}}=18{sub -6}{sup +16} ms,E{sub {alpha}}=10.66{+-}0.07 MeV) in the irradiation of the {sup 248}Cm target at a higher energy than in previous experiments. The observed nuclear decay properties of the nuclides with Z=104-118 are compared with theoretical nuclear mass calculations and the systematic trends of spontaneous fission properties. As a whole, they give a consistent pattern of decay of the 18 even-Z neutron-rich nuclides with Z=104-118 and N=163-177. The experiments were performed with the heavy-ion beam delivered by the U400 cyclotron of the FLNR (JINR, Dubna) employing the Dubna gas-filled recoil separator.

Oganessian, Yu.Ts.; Utyonkov, V.K.; Lobanov, Yu.V.; Abdullin, F.Sh.; Polyakov, A.N.; Shirokovsky, I.V.; Tsyganov, Yu.S.; Gulbekian, G.G.; Bogomolov, S.L.; Gikal, B.N.; Mezentsev, A.N.; Iliev, S.; Subbotin, V.G.; Sukhov, A.M.; Voinov, A.A.; Buklanov, G.V.; Subotic, K.; Zagrebaev, V.I.; Itkis, M.G.; Patin, J.B. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Lawrence Livermore National Laboratory, University of California, Livermore, California 94551 (United States); Russian Federal Nuclear Center, All-Russian Research Institute of Experimental Physics, 607190 Sarov (Russian Federation)] [and others

2004-12-01T23:59:59.000Z

260

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

SciTech Connect (OSTI)

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

Note: This page contains sample records for the topic "fission chain reaction" 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

Analysis of Fission Products on the AGR-1 Capsule Components  

SciTech Connect (OSTI)

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

262

Sustainable Supply Chain | Data.gov  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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,

263

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

264

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

265

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

266

Population of superdeformed bands and competition with fission  

SciTech Connect (OSTI)

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

267

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

268

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

269

Linear Momentum and Angular-Momentum Transfer in the Reactions of O-16 with Sm-154  

E-Print Network [OSTI]

between projectile-like fragments or heavy residues and their as- sociated y rays, the angular momentum transfers for a variety of incomplete fusion reactions of 180 and 310 MeV ' 0 with ' Sm have been derived. At the higher energy, the correlation... techniques may be utilized. For example, the measurements of fission cross sections in concert with momentum transfer is one method which provides some information on the partial waves involved in incomplete fusion. Such an approach has been fol- lowed...

Namboodiri, M. N.; Choudhury, R. K.; Alder, L.; Bronson, J. D.; Fabris, D.; Garg, U.; Gonthier, P. L.; Hagel, K.; Haenni, DR; Lui, YW; Majka, Z.; Mouchaty, G.; Murakami, T.; Natowitz, J. B.; Nebbia, G.; Schmitt, R. P.; Simon, S.; Sullivan, J. P.; Youngblood, David H.

1987-01-01T23:59:59.000Z

270

Differential evolution Markov chain with snooker updater and fewer chains  

SciTech Connect (OSTI)

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

271

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

SciTech Connect (OSTI)

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

272

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

273

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

274

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

275

Penetration Factor for Nuclear Fusion Reaction in Nonthermal Astrophysical Plasmas  

Science Journals Connector (OSTI)

......enhances the fusion penetration factor. In addition...nonthermal effect on the penetration factor is found to be...the fusion reaction rates of the - chain and the...effect on the fusion penetration factor decreases with...the energy generation rate (Choudhuri 2010) by......

Dai-Han Ki; Young-Dae Jung

2011-02-25T23:59:59.000Z

276

The neutronics studies of fusion fission hybrid power reactor  

SciTech Connect (OSTI)

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

277

(COMEDIE program review and fission product transport in MHTGR reactor)  

SciTech Connect (OSTI)

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

278

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

279

Nuclear Reactions in Stars  

Science Journals Connector (OSTI)

21 February 1961 research-article Nuclear Reactions in Stars T. G. Cowling Thermonuclear reactions important for the generation of stellar energy during different phases of stellar evolution are discussed. The Royal...

1961-01-01T23:59:59.000Z

280

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

Note: This page contains sample records for the topic "fission chain reaction" 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

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

282

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

283

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

SciTech Connect (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.

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

2007-09-01T23:59:59.000Z

284

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...

285

Site selectivity in the reaction of Si(111)-(7 times 7) with Si sub 2 H sub 6  

SciTech Connect (OSTI)

We find that the reaction of disilane with the Si(111)-(7{times}7) surface shows strong site selectivity. The reaction involves the fission of the Si-Si bond of Si{sub 2}H{sub 6} even at low temperatures and occurs preferentially at rest-atom sites of the 7{times}7 surface. The reaction of the products of the thermal dissociation of the surface-bound SiH{sub x} groups with surface dangling-bond sites is also site selective. We propose mechanisms to explain the above observations.

Avouris, Ph.; Bozso, F. (T. J. Watson Research Center, Yorktown Heights, NY (USA))

1990-03-22T23:59:59.000Z

286

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.

287

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

288

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

289

Source properties of intermediate-mass fragments emitted in the reaction 14N+232Th at E/A=35 MeV  

Science Journals Connector (OSTI)

Triple coincidences between intermediate-mass fragments and angle-correlated binary fission events were measured in the at E/A=35 MeV. It was found that fragments emitted at backward angles appear to be associated with reactions in which nearly all ofthe projectile momentum is carried away by the heavy reaction residue and the intermediate-mass fragment. In contrast, fragments emitted at forward angles are accompanied by 20%–30% missing momentum.

M. Fatyga; K. Kwiatkowski; V. E. Viola; W. G. Wilson; M. B. Tsang; J. Pochodzalla; W. G. Lynch; C. K. Gelbke; D. J. Fields; C. B. Chitwood; Z. Chen; T. Nayak

1987-06-15T23:59:59.000Z

290

Physical Mechanism of Nuclear Reactions at Low Energies  

E-Print Network [OSTI]

The physical mechanism of nuclear reactions at low energies caused by spatial extension of electron is considered. Nuclear reactions of this type represent intra-electronic processes, more precisely, the processes occurring inside the area of basic localization of electron. Distinctive characteristics of these processes are defined by interaction of the own field produced by electrically charged matter of electron with free nuclei. Heavy nucleus, appearing inside the area of basic localization of electron, is inevitably deformed because of interaction of protons with the adjoining layers of electronic cloud, which may cause nuclear fission. If there occur "inside" electron two or greater number of light nuclei, an attractive force appears between the nuclei which may result in the fusion of nuclei. The intra-electronic mechanism of nuclear reactions is of a universal character. For its realization it is necessary to have merely a sufficiently intensive stream of free electrons, i.e. heavy electric current, and as long as sufficiently great number of free nuclei. This mechanism may operate only at small energies of translational motion of the centers of mass of nuclei and electron. Because of the existence of simple mechanism of nuclear reactions at low energies, nuclear reactor turns out to be an atomic delayed-action bomb which may blow up by virtue of casual reasons, as it has taken place, apparently, in Chernobyl. The use of cold nuclear reactions for production of energy will provide mankind with cheap, practically inexhaustible, and non-polluting energy sources.

V. P. Oleinik; Yu. D Arepjev

2003-06-09T23:59:59.000Z

291

Thermal Performance of Deep-Burn Fusion-Fission Hybrid Waste in a Repository  

SciTech Connect (OSTI)

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

292

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

SciTech Connect (OSTI)

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

293

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

294

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

295

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

296

Deep Atomic Binding (DAB) Approach in Interpretation of Fission Products Behavior in Terrestrial and Water Ecosystems  

SciTech Connect (OSTI)

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

297

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

298

Radiological Aspects of Deep-Burn Fusion-Fission Hybrid Waste in a Repository  

SciTech Connect (OSTI)

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

299

Method for polymer synthesis in a reaction well  

DOE Patents [OSTI]

A method of synthesis is described for building a polymer chain, oligonucleotides in particular, by sequentially adding monomer units to at least one solid support for growing and immobilizing a polymer chain thereon in a liquid reagent solution. The method includes the step of: (A) depositing a liquid reagent in a reaction well in contact with at least one solid support and at least one monomer unit of the polymer chain affixed to the solid support. The well includes at least one orifice extending into the well, and is of a size and dimension to form a capillary liquid seal to retain the reagent solution in the well to enable polymer chain growth on the solid support. The method further includes the step of (B) expelling the reagent solution from the well, while retaining the polymer chain therein. This is accomplished by applying a first gas pressure to the reaction well such that a pressure differential between the first gas pressure and a second gas pressure exerted on an exit of the orifice exceeds a predetermined amount sufficient to overcome the capillary liquid seal and expel the reagent solution from the well through the orifice exit. 9 figs.

Brennan, T.M.

1998-09-29T23:59:59.000Z

300

Controlled Nuclear Fusion Reactions  

Science Journals Connector (OSTI)

... THE presentation of full and authoritative accounts of research on controlled nuclear fusion reactions was a major feature of the second Geneva Conference on the Peaceful Uses of ...

R. S. PEASE

1958-10-18T23:59:59.000Z

Note: This page contains sample records for the topic "fission chain reaction" 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

Single chain elasticity and thermoelasticity of polyethylene  

E-Print Network [OSTI]

Single-chain elasticity of polyethylene at $\\theta$ point up to 90% of stretching with respect to its contour length is computed by Monte-Carlo simulation of an atomistic model in continuous space. The elasticity law together with the free-energy and the internal energy variations with stretching are found to be very well represented by the wormlike chain model up to 65% of the chain elongation, provided the persistence length is treated as a temperature dependent parameter. Beyond this value of elongation simple ideal chain models are not able to describe the Monte Carlo data in a thermodynamic consistent way. This study reinforces the use of the wormlike chain model to interpret experimental data on the elasticity of synthetic polymers in the finite extensibility regime, provided the chain is not yet in its fully stretched regime. Specific solvent effects on the elasticity law and the partition between energetic and entropic contributions to single chain elasticity are investigated.

John T. Titantah; Carlo Pierleoni; Jean-Paul Ryckaert

2002-09-05T23:59:59.000Z

302

Robertsonian fusion and centric fission in karyotype evolution of higher plants  

Science Journals Connector (OSTI)

Robertsonian fusion and centric fission are uniquely detectable in ... karyotype patterns. They are the most important types of karyotype change in animals but seem ... flow. The number of reported cases of fusion

Keith Jones

303

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

SciTech Connect (OSTI)

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

304

Dosimetry of fission neutrons in a 1-W reactor, UTR-Kinki  

Science Journals Connector (OSTI)

......2, the neutron energy spectrum calculated by MCNP4B...technique and the thermal neutron fluence rates from...determining the energy spectrum of the reactor's fission neutrons. It also...value, the activity induced in the In foils......

Satoru Endo; Eiji Yoshida; Yusuke Yoshitake; Tetsuo Horiguchi; Wenyi Zhang; Kazuo Fujikawa; Masaharu Hoshi; Tetsuo Itoh; Masayori Ishikawa; Kiyoshi Shizuma

2002-12-01T23:59:59.000Z

305

Ternary particles with extreme N/Z ratios from neutron-induced fission  

SciTech Connect (OSTI)

The existing ternary fission models can well reproduce the yields of the most abundant light charged particles. However, these models tend to significantly overestimate the yields of ternary particles with an extreme N/Z ratio: {sup 3}He, {sup 11}Li, {sup 14}Be, etc. The experimental yields of these isotopes were investigated with the recoil separator LOHENGRIN down to a level of 10{sup {minus}10} per fission. Results from the fissioning systems {sup 233}U (n{sub th}, f), {sup 235}U(n{sub th},f), {sup 239}Pu(n{sub th},f) {sup 241}Pu(n{sub th},f) and {sup 245}Cm(n{sub th},f) are presented and the implications for the ternary fission models are discussed.

Koster, U.; Faust, H.; Friedrichs, T.; Oberstedt, S.; Fioni, G.; Grob, M.; Ahmad, I. J.; Devlin, M.; Heinz, A.; Kondev, F. G.; Lauritsen, T.; Sarantites, D. G.; Siem, S.; Sobotka, L. G.; Sonzogni, A.

2000-05-16T23:59:59.000Z

306

Born-Oppenheimer expansion: From muon distribution to dissipation in fission  

Science Journals Connector (OSTI)

It is shown that a consistent treatment of momentum translation by a muon in the problem of the distribution of muons among prompt-fission fragments modifies the nonadiabatic transition operator in the Born-Oppenheimer

F. F. Karpeshin

2000-05-01T23:59:59.000Z

307

Interaction of noble-metal fission products with pyrolytic silicon carbide  

SciTech Connect (OSTI)

Fuel particles for the High-Temperature Gas-Cooled Reactor (HTGR) contain layers of pyrolytic carbon and silicon carbide, which act as a miniature pressure vessel and form the primary fission product barrier. Of the many fission products formed during irradiation, the noble metals are of particular interest because they interact significantly with the SiC layer and their concentrations are somewhat higher in the low-enriched uranium fuels currently under consideration. To study fission product-SiC interactions, particles of UO/sub 2/ or UC/sub 2/ are doped with fission product elements before coating and are then held in a thermal gradient up to several thousand hours. Examination of the SiC coatings by TEM-AEM after annealing shows that silver behaves differently from the palladium group.

Lauf, R.J.; Braski, D.N.

1982-01-01T23:59:59.000Z

308

Slow light enhanced singlet exciton fission solar cells with a 126% yield of electrons per photon  

E-Print Network [OSTI]

Singlet exciton fission generates two triplet excitons per absorbed photon. It promises to increase the power extracted from sunlight without increasing the number of photovoltaic junctions in a solar cell. We demonstrate ...

Thompson, Nicholas J.

309

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

Science Journals Connector (OSTI)

The energy costs in the cold ternary fission of 252Cf for various light charged particle emission are calculated by including Wong’s correction for Coulomb potential. Energy cost is found to be higher in cold ......

P V KUNHIKRISHNAN; K P SANTHOSH

2013-01-01T23:59:59.000Z

310

E-Print Network 3.0 - aromatic side chain Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

1. Interactions between oppositely charged amino acid side- chains in the interaction interface... chain- main chain, main chain- sidechain and sidechain-side- chain. Only...

311

A comparison of radioactive waste from first generation fusion reactors and fast fission reactors with actinide recycling  

SciTech Connect (OSTI)

Limitations of the fission fuel resources will presumably mandate the replacement of thermal fission reactors by fast fission reactors that operate on a self-sufficient closed fuel cycle. This replacement might take place within the next one hundred years, so the direct competitors of fusion reactors will be fission reactors of the latter rather than the former type. Also, fast fission reactors, in contrast to thermal fission reactors, have the potential for transmuting long-lived actinides into short-lived fission products. The associated reduction of the long-term activation of radioactive waste due to actinides makes the comparison of radioactive waste from fast fission reactors to that from fusion reactors more rewarding than the comparison of radioactive waste from thermal fission reactors to that from fusion reactors. Radioactive waste from an experimental and a commercial fast fission reactor and an experimental and a commercial fusion reactor has been characterized. The fast fission reactors chosen for this study were the Experimental Breeder Reactor 2 and the Integral Fast Reactor. The fusion reactors chosen for this study were the International Thermonuclear Experimental Reactor and a Reduced Activation Ferrite Helium Tokamak. The comparison of radioactive waste parameters shows that radioactive waste from the experimental fast fission reactor may be less hazardous than that from the experimental fusion reactor. Inclusion of the actinides would reverse this conclusion only in the long-term. Radioactive waste from the commercial fusion reactor may always be less hazardous than that from the commercial fast fission reactor, irrespective of the inclusion or exclusion of the actinides. The fusion waste would even be far less hazardous, if advanced structural materials, like silicon carbide or vanadium alloy, were employed.

Koch, M.; Kazimi, M.S.

1991-04-01T23:59:59.000Z

312

Microscopic description of fission in Uranium isotopes with the Gogny energy density functional  

E-Print Network [OSTI]

The most recent parametrizations D1S, D1N and D1M of the Gogny energy density functional are used to describe fission in the isotopes $^{232-280}$ U. Fission paths, collective masses and zero point quantum corrections, obtained within the constrained Hartree-Fock-Bogoliubov approximation, are used to compute the systematics of the spontaneous fission half-lives $t_\\mathrm{SF}$, the masses and charges of the fission fragments as well as their intrinsic shapes. The Gogny-D1M parametrization has been benchmarked against available experimental data on inner and second barrier heights, excitation energies of the fission isomers and half-lives in a selected set of Pu, Cm, Cf, Fm, No, Rf, Sg, Hs and Fl nuclei. It is concluded that D1M represents a reasonable starting point to describe fission in heavy and superheavy nuclei. Special attention is also paid to understand the uncertainties in the predicted $t_\\mathrm{SF}$ values arising from the different building blocks entering the standard semi-classical Wentzel-Kramers-Brillouin formula. Although the uncertainties are large, the trend with mass or neutron numbers are well reproduced and therefore the theory still has predictive power. In this respect, it is also shown that modifications of a few per cent in the pairing strength can have a significant impact on the collective masses leading to uncertainties in the $t_\\mathrm{SF}$ values of several orders of magnitude.

R. Rodriguez-Guzman; L. M. Robledo

2014-05-25T23:59:59.000Z

313

Detailed Chemical Kinetic Reaction Mechanism for Biodiesel Components Methyl Stearate and Methyl Oleate  

SciTech Connect (OSTI)

New chemical kinetic reaction mechanisms are developed for two of the five major components of biodiesel fuel, methyl stearate and methyl oleate. The mechanisms are produced using existing reaction classes and rules for reaction rates, with additional reaction classes to describe other reactions unique to methyl ester species. Mechanism capabilities were examined by computing fuel/air autoignition delay times and comparing the results with more conventional hydrocarbon fuels for which experimental results are available. Additional comparisons were carried out with measured results taken from jet-stirred reactor experiments for rapeseed methyl ester fuels. In both sets of computational tests, methyl oleate was found to be slightly less reactive than methyl stearate, and an explanation of this observation is made showing that the double bond in methyl oleate inhibits certain low temperature chain branching reaction pathways important in methyl stearate. The resulting detailed chemical kinetic reaction mechanism includes more approximately 3500 chemical species and more than 17,000 chemical reactions.

Naik, C; Westbrook, C K; Herbinet, O; Pitz, W J; Mehl, M

2010-01-22T23:59:59.000Z

314

New developments in direct nuclear fission energy conversion devices  

SciTech Connect (OSTI)

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

315

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

316

Fusion materials irradiations at MaRIE's fission fusion facility  

SciTech Connect (OSTI)

Los Alamos National Laboratory's proposed signature facility, MaRIE, will provide scientists and engineers with new capabilities for modeling, synthesizing, examining, and testing materials of the future that will enhance the USA's energy security and national security. In the area of fusion power, the development of new structural alloys with better tolerance to the harsh radiation environments expected in fusion reactors will lead to improved safety and lower operating costs. The Fission and Fusion Materials Facility (F{sup 3}), one of three pillars of the proposed MaRIE facility, will offer researchers unprecedented access to a neutron radiation environment so that the effects of radiation damage on materials can be measured in-situ, during irradiation. The calculated radiation damage conditions within the F{sup 3} match, in many respects, that of a fusion reactor first wall, making it well suited for testing fusion materials. Here we report in particular on two important characteristics of the radiation environment with relevancy to radiation damage: the primary knock-on atom spectrum and the impact of the pulse structure of the proton beam on temporal characteristics of the atomic displacement rate. With respect to both of these, analyses show the F{sup 3} has conditions that are consistent with those of a steady-state fusion reactor first wall.

Pitcher, Eric J [Los Alamos National Laboratory

2010-10-06T23:59:59.000Z

317

Spontaneous symmetry breaking and the chain criterion  

Science Journals Connector (OSTI)

For the first time I have rigorously proved the equivalence between the necessary symmetry condition of the original Landau theory of second-order phase transitions, the chain criterion, and some recent propositions. I have introduced the new chain criterion which contains a powerful corollary. I have also established the validity of the chain criterion beyond the Landau theory, emphasizing its use as an algorithm for calculation of little groups.

Marko V. Jari?

1981-04-01T23:59:59.000Z

318

Reactor for exothermic reactions  

DOE Patents [OSTI]

A liquid phase process is described for oligomerization of C[sub 4] and C[sub 5] isoolefins or the etherification thereof with C[sub 1] to C[sub 6] alcohols wherein the reactants are contacted in a reactor with a fixed bed acid cation exchange resin catalyst at an LHSV of 5 to 20, pressure of 0 to 400 psig and temperature of 120 to 300 F. Wherein the improvement is the operation of the reactor at a pressure to maintain the reaction mixture at its boiling point whereby at least a portion but less than all of the reaction mixture is vaporized. By operating at the boiling point and allowing a portion of the reaction mixture to vaporize, the exothermic heat of reaction is dissipated by the formation of more boil up and the temperature in the reactor is controlled.

Smith, L.A. Jr.; Hearn, D.; Jones, E.M. Jr.

1993-03-02T23:59:59.000Z

319

Aqueous Phase Reactions  

Science Journals Connector (OSTI)

The use of water as a solvent for carrying out organic reactions was nonexistent till about the middle of the 20th century. In view of the environmental concerns caused by pollution of organic solvents, chemis...

V. K. Ahluwalia; M. Kidwai

2004-01-01T23:59:59.000Z

320

Photosynthesis: First reactions  

Science Journals Connector (OSTI)

Photosynthesis: First reactions ... Studies of photosynthesis using isotopic tracers have revealed the first steps of carbohydrate synthesis, from which are derived the multitude of compounds needed by the plant. ... Photosynthesis ...

Andrew A. Benson

1954-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "fission chain reaction" 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

Linear chain tensioning of moored production vessels  

SciTech Connect (OSTI)

Part 1 of this two-part series discussed the worldwide floating production vessel (FPV) market and evolution of the linear puller concept. The three principal types of chain jack systems - hollow ram, single and twin cylinders - were introduced. And advantages of this relatively new form of passive mooring were outlined. This concluding article covers applications of linear chain pullers on various vessels, including use on an example 35,000-t North Sea semi-submersible. Chain wear and how linear pullers avoid wear associated with windlass-type systems are discussed, along with the optimization possible through use of a swiveling chain fair-lead latch (SCFL).

Peters, B. (Bardex Corp., London (United Kingdom))

1993-06-01T23:59:59.000Z

322

Better Plants Supply Chain Pilot Overview  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

be helping their suppliers achieve energy and cost savings, while simultaneously reducing carbon emissions. This can lead to stronger, more competitive supply chains and help...

323

Optimizing a Retailer's Containerized Import Supply Chain  

E-Print Network [OSTI]

M.G. , 2005. Distribution network design: New problems andapproach for distribution chain design in agile virtualinto a strategic distribution network design model with

Davidson, Evan Taitz

2012-01-01T23:59:59.000Z

324

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

SciTech Connect (OSTI)

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

325

Supply Chain The effective supply chain has become a new organizational and operational  

E-Print Network [OSTI]

MBA in Supply Chain Management #12;The effective supply chain has become a new organizational a virtual integration of business partners to achieve new levels of efficiency and productivity, as well

Lin, Xiaodong

326

Singlet-Fission Sensitizers for Ultra-High Efficiency Excitonic Solar Cells: 15 August 2005 - 14 October 2008  

SciTech Connect (OSTI)

We have considered the potential benefits offered by using singlet fission sensitizers in photovoltaic cells and identified two key issues involved in the search for such sensitizers.

Michl, J.

2008-12-01T23:59:59.000Z

327

Fission product transport and behavior during two postulated loss-of-flow transients in the Advanced Test Reactor  

SciTech Connect (OSTI)

The fission product behavior during two postulated loss-of-flow accidents (leading to high- and low-pressure core degradations) in the Advanced Test Reactor (ATR) has been analyzed. These transients are designated ATR transients LCP 15 (high pressure) and LPP9 (low pressure). Normally, transients of this nature would be easily mitigated using existing safety systems and procedures. In these analyses, failure of these safety systems was assumed so that core degradation and fission product release could be studied. A probabilistic risk analysis was performed that indicated that the probability of occurrence for these two transients is on the order of 10[sup [minus]5] and 10[sup [minus]7] per reactor year for LCP15 and LPP9, respectively. The fission product behavior analysis included calculations of the gaseous and highly volatile fission product (xenon, krypton, cesium, iodine, and tellurium) inventories in the fuel before accident initiation, release of the fission products from the fuel into the reactor vessel during core melt, the probable chemical forms, and transport of the fission products from the core through the reactor vessel and existing piping to the confinement. In addition to a base-case analysis of fission product behavior, a series of analyses was performed to determine the sensitivity of fission product release to several parameters including steam flow rate, (structural) aluminum oxidation, and initial aerosol size. The base-case analyses indicate that the volatile fission products (excluding the noble gases) will be transported as condensed species on zinc aerosols.

Adams, J.P.; Carboneau, M.L.; Hagrman, D.L. (Idaho National Engineering Lab. EG and G Idaho, Idaho Falls, ID (United States))

1993-07-01T23:59:59.000Z

328

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

329

Introduction The Sustainable Supply Chain Taxes Permits Integration Future Research Sustainable Supply Chains  

E-Print Network [OSTI]

Introduction The Sustainable Supply Chain Taxes Permits Integration Future Research Sustainable;Introduction The Sustainable Supply Chain Taxes Permits Integration Future Research 1 Introduction 2 The Sustainable Supply Chain 3 Taxes 4 Permits 5 Integration 6 Future Research Dissertation Defense by Trisha D

Nagurney, Anna

330

Fashion Supply Chain Network Competition Ecolabelling  

E-Print Network [OSTI]

, energy, as well as chemicals. For example, it is estimated that cotton uses only 3% of the worldFashion Supply Chain Network Competition with Ecolabelling Anna Nagurney1,2 , Min Yu3 , and Jonas April 2014; revised June 2014 To appear in Sustainable Fashion Supply Chain Management: From Sourcing

Nagurney, Anna

331

Supply Chain Networks: Challenges and Opportunities  

E-Print Network [OSTI]

School of Management University of Massachusetts Amherst, Massachusetts 01003 Department of Management, and consumers at the demand markets. Today, supply chains may span thousands of miles across the globe, involve as the stability and resiliency of supply chains, as well as their adaptability and responsiveness to events

Nagurney, Anna

332

Supply Chain Networks: Challenges and Opportunities  

E-Print Network [OSTI]

School of Management University of Massachusetts Amherst, Massachusetts 01003 Boston INFORMS Chapter and suppliers, distributors, retailers, and consumers at the demand markets. Today, supply chains may span chains, as well as their adaptability and responsiveness to events in a global environment of increasing

Nagurney, Anna

333

Supply Chain Networks: Challenges and Opportunities  

E-Print Network [OSTI]

School of Management University of Massachusetts Amherst, Massachusetts 01003 International Conference of manufacturers and suppliers, distributors, retailers, and consumers at the demand markets. Today, supply chains chains, as well as their adaptability and responsiveness to events in a global environment of increasing

Nagurney, Anna

334

Supply Chains and Transportation Networks Anna Nagurney  

E-Print Network [OSTI]

Management Isenberg School of Management University of Massachusetts Amherst, Massachusetts 01003 December, and consumers at the demand markets. Supply chains are the backbones of our globalized Network Economy of cooperation. For example, in a vertically integrated supply chain the same firm may be responsible

Nagurney, Anna

335

Free Energy of the Antiferromagnetic Linear Chain  

Science Journals Connector (OSTI)

Rigorous upper and lower bounds for the free energy of the antiferromagnetic Heisenberg linear chain are obtained from general convexity properties of the free energy. The lower bound is here derived; the upper bound has been obtained previously by Bulaevskii. Both are compared with the calculations of Bonner and Fisher for finite chains.

Robert B. Griffiths

1964-11-02T23:59:59.000Z

336

Internal Markets for Supply Chain Capacity Allocation  

E-Print Network [OSTI]

Internal Markets for Supply Chain Capacity Allocation David McAdams and Thomas W. Malone Sloan David McAdams & Thomas Malone #12;Internal Markets for Supply Chain Capacity Allocation David Mc ("internal markets") to help allocate manufacturing capacity and determine the prices, delivery dates

337

Double Counting in Supply Chain Carbon Footprinting  

Science Journals Connector (OSTI)

Carbon footprinting is a tool for firms to determine the total greenhouse gas GHG emissions associated with their supply chain or with a unit of final product or service. Carbon footprinting typically aims to identify where best to invest in emission ... Keywords: carbon footprint, emissions allocation, supply chain, sustainable operations

Felipe Caro; Charles J. Corbett; Tarkan Tan; Rob Zuidwijk

2013-10-01T23:59:59.000Z

338

Right-left asymmetry of radiation from fission induced by polarised neutrons  

E-Print Network [OSTI]

The effect of the right-left asymmetry is considered in the angular distribution of gamma quanta from fission of U-235 by polarised thermal neutrons, which depends on the polarisation of the neutrons with respect to the gamma-fission plane. Electric dipole radiation from fission fragments arising due to the Strutinsky-Denisov induced polarisation mechanism may give rise to such an effect. Earlier, this mechanism was shown to fit the non-statistical part observed in the gamma spectrum from spontaneous fission of Cf-252. The calculated value of the magnitude of the asymmetry parameter is on the level of 10$^{-4}$. That is in agreement with the current experimental data. A crucial experiment to give a more definite picture of the concrete mechanism would be determination of the energy of the quanta responsible for the asymmetry. Detection of the quanta with the energy of ~5 MeV approaching the giant dipole resonance is needed in order to identify prompt gamma rays emitted at the stage of fissioning.

F. F. Karpeshin

2009-02-09T23:59:59.000Z

339

Right-left asymmetry of radiation from fission induced by polarised neutrons  

E-Print Network [OSTI]

The effect of the right-left asymmetry is considered in the angular distribution of gamma quanta from fission of U-235 by polarised thermal neutrons, which depends on the polarisation of the neutrons with respect to the gamma-fission plane. Electric dipole radiation from fission fragments arising due to the Strutinsky-Denisov induced polarisation mechanism may give rise to such an effect. Earlier, this mechanism was shown to fit the non-statistical part observed in the gamma spectrum from spontaneous fission of Cf-252. The calculated value of the magnitude of the asymmetry parameter is on the level of 10$^{-4}$. That is in agreement with the current experimental data. A crucial experiment to give a more definite picture of the concrete mechanism would be determination of the energy of the quanta responsible for the asymmetry. Detection of the quanta with the energy of ~5 MeV approaching the giant dipole resonance is needed in order to identify prompt gamma rays emitted at the stage of fissioning.

Karpeshin, F F

2009-01-01T23:59:59.000Z

340

Ternary Fission of {sup 249}Cf(n,f) and {sup 250}Cf(SF)  

SciTech Connect (OSTI)

During the last years, several Cm and Cf isotopes have been studied by our research group in the frame of a systematic investigation of gas emission characteristics in ternary fission. Here we report on new results on the energy distribution and the emission probability of {sup 3}H, {sup 4}He and {sup 6}He particles emitted in the spontaneous ternary fission of {sup 250}Cf (E{sub exc} = 0 MeV) and in the neutron induced ternary fission of {sup 249}Cf (E{sub exc} = 6.625 MeV). Both measurements were performed using suited and well-calibrated ΔE-E telescope detectors, at the IRMM (Geel, Belgium) for the spontaneous fission and at the very intense neutron beam PF1b at the Institute Laue-Langevin (Grenoble, France) for the neutron induced fission measurement. In this way, the existing database can be enlarged with new results for Z=98 isotopes, which is important for the systematic investigation. Moreover, the investigation of the 'isotope couple' {sup 249}Cf(n,f) - {sup 250}Cf(SF), together with corresponding data for other isotopes, will yield valuable information on the influence of the excitation energy on the particle emission probabilities.

University of Gent, B-9000 Gent, Belgium; CEA Cadarache, F-13108 Saint-Paul-lez-Durance, France; Institute Laue-Langevin, F-38042 Grenoble, France; EC-JRC Institute for Reference Materials and Measurements, B-2440 Geel, Belgium; Wadsworth Center, New York State Department of Health, Albany NY 12201, USA; Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Vermote, S.; Wagemans, C.; Serot, O.; Soldner, T.; Geltenbort, P.; Gils, J. Van; Almahamid, I.; Tian, G.; Rao, L.

2011-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "fission chain reaction" 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

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

342

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

SciTech Connect (OSTI)

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

343

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

SciTech Connect (OSTI)

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

344

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

345

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

346

Quasifission and difference in formation of evaporation residues in the $^{16}$O+$^{184}$W and $^{19}$F+$^{181}$Ta reactions  

E-Print Network [OSTI]

The excitation functions of capture, complete fusion, and evaporation residue formation in the $^{16}$O+$^{184}$W and $^{19}$F+$^{181}$Ta reactions leading to the same $^{200}$Pb compound nucleus has been studied theoretically to explain the experimental data showing more intense yield of evaporation residue in the former reaction in comparison with that in the latter reaction. The observed difference is explained by large capture cross section in the former and by increase of the quasifission contribution to the yield of fission-like fragments in the $^{19}$F+$^{181}$Ta reaction at large excitation energies. The probability of compound nucleus formation in the $^{16}$O+$^{184}$W reaction is larger but compound nuclei formed in both reactions have similar angular momentum ranges at the same excitation energy. The observed decrease of evaporation residue cross section normalized to the fusion cross section in the $^{19}$F+$^{181}$Ta reaction in comparison with the one in the $^{16}$O+$^{184}$W reaction at high excitation energies is explained by the increase of hindrance in the formation of compound nucleus connected with more quick increase of the quasifission contribution in the $^{19}$F induced reaction. The spin distributions of the evaporation residue cross sections for the two reactions are also presented.

A. K. Nasirov; G. Mandaglio; M. Manganaro; A. I. Muminov; G. Fazio; G. Giardina

2009-08-13T23:59:59.000Z

347

Measurement of Fission Neutron Spectrum and Multiplicity using a Gamma Tag Double Time-of-flight Setup  

Science Journals Connector (OSTI)

Abstract Recent efforts have been made to improve the prompt fission neutron spectrum and nu-bar measurements for Uranium and Plutonium isotopes particularly in the keV region. A system has been designed at Rensselaer Polytechnic Institute (RPI) utilizing an array of EJ-301 liquid scintillators as well as lithium glass and plastic scintillators to experimentally determine these values. An array of BaF 2 detectors was recently obtained from Oak Ridge National Laboratory to be used in conjunction with the neutron detectors. The system uses a novel gamma tagging method for fission which can offer an improvement over conventional fission chambers due to increased sample mass. A coincidence requirement on the gamma detectors from prompt fission gammas is used as the fission tag for the system as opposed to fission fragments in a conventional fission chamber. The system utilizes pulse digitization using Acqiris 8 bit digitizer boards which allow for gamma/neutron pulse height discrimination on the liquid scintillators during post processing. Additionally, a 252Cf fission chamber was designed and constructed at RPI which allowed for optimization and testing of the system without the need for an external neutron source. The characteristics of the gamma tagging method such as false detection rate and detection efficiency were determined using this fission chamber and verified using MCNP Polimi modeling. Prompt fission neutron spectrum data has been taken using the fission chamber focusing on the minimum detectable neutron energy for each of the various detectors. Plastic scintillators were found to offer a significant improvement over traditional liquid scintillators allowing energy measurements down to 50 keV. Background was also characterized for all detectors and will be discussed.

E. Blain; A. Daskalakis; Y. Danon

2014-01-01T23:59:59.000Z

348

Single-Chain Antibody Library  

DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

Researchers at Pacific Northwest National Laboratory (PNNL) have constructed a nonimmune library consisting of 109 human antibody scFv fragments, which have been cloned and expressed on the surface of yeast. Nanomolar-affinity scFvs are routinely obtained by magnetic bead screening and flow cytometric sorting. The yeast library can be amplified 1010 fold without measurable loss of clonal diversity. This allows for indefinite expansion of the library. All scFv clones can be assessed directly on the yeast cell surface by immunofluorescent labeling and flow cytometry, obviating separate subcloning, expression, and purification steps. The ability to use multiplex library screening demonstrates the utility of this approach for high-throughput antibody isolation for proteomic applications. The yeast library may be used for research projects or teaching performed for U.S. Government purposes only. If you would like to request an aliquot of the single-chain antibody library for your research, please print and fill out the Materials Transfer Agreement (MTA) [PDF, 20K]. The website provides the contact information for mailing the MTA. [copied from http://www.sysbio.org/dataresources/singlechain.stm

Baird, Cheryl

349

Thermodynamics of multiferroic spin chains  

Science Journals Connector (OSTI)

The minimal model to describe many spin-chain materials with ferroelectric properties is the Heisenberg model with ferromagnetic nearest-neighbor coupling J1 and antiferromagnetic next-nearest-neighbor coupling J2. Here we study the thermodynamics of this model using a density-matrix algorithm applied to transfer matrices. We find that the incommensurate spin-spin correlations—crucial for the ferroelectric properties and the analog of the classical spiral pitch angle—depend not only on the ratio J2/|J1| but also strongly on temperature. We study small easy-plane anisotropies which can stabilize a vector chiral order as well as the finite-temperature signatures of multipolar phases, stable at finite magnetic field. Furthermore, we fit the susceptibilities of LiCuVO4, LiCu2O2, and Li2ZrCuO4. Contrary to the literature, we find that for LiCuVO4 the best fit is obtained with J2?90?K and J2/|J1|?0.5 and show that these values are consistent with the observed spin incommensurability. Finally, we discuss our findings concerning the incommensurate spin-spin correlations and multipolar orders in relation to future experiments on these compounds.

J. Sirker

2010-01-26T23:59:59.000Z

350

Velocity pump reaction turbine  

DOE Patents [OSTI]

An expanding hydraulic/two-phase velocity pump reaction turbine including a dual concentric rotor configuration with an inter-rotor annular flow channel in which the inner rotor is mechanically driven by the outer rotor. In another embodiment, the inner rotor is immobilized and provided with gas recovery ports on its outer surface by means of which gas in solution may be recovered. This velocity pump reaction turbine configuration is capable of potential energy conversion efficiencies of up to 70%, and is particularly suited for geothermal applications.

House, Palmer A. (Walnut Creek, CA)

1982-01-01T23:59:59.000Z

351

Velocity pump reaction turbine  

DOE Patents [OSTI]

An expanding hydraulic/two-phase velocity pump reaction turbine including a dual concentric rotor configuration with an inter-rotor annular flow channel in which the inner rotor is mechanically driven by the outer rotor. In another embodiment, the inner rotor is immobilized and provided with gas recovery ports on its outer surface by means of which gas in solution may be recovered. This velocity pump reaction turbine configuration is capable of potential energy conversion efficiencies of up to 70%, and is particularly suited for geothermal applications.

House, Palmer A. (Walnut Creek, CA)

1984-01-01T23:59:59.000Z

352

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

353

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

354

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

355

Structure of Human Ferritin L Chain  

SciTech Connect (OSTI)

Ferritin is the major iron-storage protein present in all cells. It generally contains 24 subunits, with different ratios of heavy chain (H) to light chain (L), in the shape of a hollow sphere hosting up to 4500 ferric Fe atoms inside. H-rich ferritins catalyze the oxidation of iron(II), while L-rich ferritins promote the nucleation and storage of iron(III). Several X-ray structures have been determined, including those of L-chain ferritins from horse spleen (HoSF), recombinant L-chain ferritins from horse (HoLF), mouse (MoLF) and bullfrog (BfLF) as well as recombinant human H-chain ferritin (HuHF). Here, structures have been determined of two crystal forms of recombinant human L-chain ferritin (HuLF) obtained from native and perdeuterated proteins. The structures show a cluster of acidic residues at the ferrihydrite nucleation site and at the iron channel along the threefold axis. An ordered Cd{sup 2+} structure is observed within the iron channel, offering further insight into the route and mechanism of iron transport into the capsid. The loop between helices D and E, which is disordered in many other L-chain structures, is clearly visible in these two structures. The crystals generated from perdeuterated HuLF will be used for neutron diffraction studies.

Wang,Z.; Li, C.; Ellenburg, M.; Soistman, E.; Ruble, J.; Wright, B.; Ho, J.; Carter, D.

2006-01-01T23:59:59.000Z

356

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

357

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

358

PHYSICAL REVIEW C 81, 014607 (2010) Fission fragment mass and energy distributions as a function of incident neutron energy measured  

E-Print Network [OSTI]

of incident neutron energy measured in a lead slowing-down spectrometer C. Romano,1 Y. Danon,1,* R. Block,1 J; published 19 January 2010) A new method of measuring fission fragment mass and energy distributions to measure the neutron-induced fission cross section and fragment mass and energy distributions of 25.3 ± 0

Danon, Yaron

359

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

360

The Fission Yeast Copper-sensing Transcription Factor Cuf1 Regulates the Copper Transporter Gene Expression through an  

E-Print Network [OSTI]

The Fission Yeast Copper-sensing Transcription Factor Cuf1 Regulates the Copper Transporter Gene of copper transport is essential for copper homeostasis and growth in yeast. Analysis of regulatory regions in the promoter of the ctr4 copper transporter gene in fission yeast Schizosaccharomyces pombe re- veals

Labbé, Simon

Note: This page contains sample records for the topic "fission chain reaction" 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

Reaction product imaging  

SciTech Connect (OSTI)

Over the past few years the author has investigated the photochemistry of small molecules using the photofragment imaging technique. Bond energies, spectroscopy of radicals, dissociation dynamics and branching ratios are examples of information obtained by this technique. Along with extending the technique to the study of bimolecular reactions, efforts to make the technique as quantitative as possible have been the focus of the research effort. To this end, the author has measured the bond energy of the C-H bond in acetylene, branching ratios in the dissociation of HI, the energetics of CH{sub 3}Br, CD{sub 3}Br, C{sub 2}H{sub 5}Br and C{sub 2}H{sub 5}OBr dissociation, and the alignment of the CD{sub 3} fragment from CD{sub 3}I photolysis. In an effort to extend the technique to bimolecular reactions the author has studied the reaction of H with HI and the isotopic exchange reaction between H and D{sub 2}.

Chandler, D.W. [Sandia National Laboratories, Livermore, CA (United States)

1993-12-01T23:59:59.000Z

362

Ion-Molecule Reactions  

Science Journals Connector (OSTI)

...de-gree of agreement between theory and experiment is achieved from...criticisms, how-ever, the theory of the orbiting complex appears...rigorous description of the basic physics of the reaction com-plex. Most criticisms of the theory should more properly be addressed...

J. H. Futrell; T. O. Tiernan

1968-10-25T23:59:59.000Z

363

Gaseous fission product management for molten salt reactors and vented fuel systems  

SciTech Connect (OSTI)

Fission gas disposal is one of the unresolved difficulties for Molten Salt Reactors (MSRs) and advanced reactors with vented fuel systems. As these systems operate, they produce many radioactive isotopes of xenon and krypton (e.g. {sup 135}Xe t{sub 1/2} = 9.14 hours and {sup 85}Kr t{sub 1/2}= 10.73 years). Removing these gases proves vital to the success of such reactor designs for two reasons. First, the gases act as large neutron sinks which decrease reactivity and must be counterbalanced by increasing fuel loading. Second, for MSRs, inert fission product gases naturally separate quickly from high temperature salts, thus creating high vapor pressure which poses safety concerns. For advanced reactors with solid vented fuel, the gases are allowed to escape into an off-gas system and thus must be managed. Because of time delays in transport of fission product gases in vented fuel systems, some of the shorter-lived radionuclides will decay away thereby reducing the fission gas source term relative to an MSR. To calculate the fission gas source term of a typical molten salt reactor, we modeled a 1000 MWe graphite moderated thorium MSR similar to that detailed in Mathieu et al. [1]. The fuel salt used in these calculations was LiF (78 mole percent) - (HN)F 4 (22 mole percent) with a heavy nuclide composition of 3.86% {sup 233}U and 96.14% {sup 232}Th by mass. Before we can remove the fission product gases produced by this reactor configuration, we must first develop an appropriate storage mechanism. The gases could be stored in pressurized containers but then one must be concerned about bottle failure. Methods to trap noble gases in matrices are expensive and complex. Alternatively, there are direct storage/disposal options: direct injection into the Earth or injecting a grout-based product into the Earth. Advances in drilling technologies, hydro fracture technologies, and methods for the sequestration of carbon dioxide from fossil fuel plants are creating new options for disposal of fission gas wastes. In each option, lithostatic pressure, a kilometer or more underground, eliminates the pressure driving force for noble gas release and dissolves any untrapped gas in deep groundwater or into incorporated solid waste forms. The options, challenges, and potential for these methods to dispose of gaseous fission products are described. With this research, we hope to help both MSRs and other advanced reactors come one step closer to commercialization. (authors)

Messenger, S. J. [Massachusetts Inst. of Technology, 77 Massachusetts Ave., 54-1717, Cambridge, MA 02139 (United States); Forsberg, C. [Massachusetts Inst. of Technology, 77 Massachusetts Ave., 24-207, Cambridge, MA 02139 (United States); Massie, M. [Massachusetts Inst. of Technology, 77 Massachusetts Ave., NW12-230, Cambridge, MA 02139 (United States)

2012-07-01T23:59:59.000Z

364

Slow light enhanced singlet exciton fission solar cells with a 126% yield of electrons per photon  

SciTech Connect (OSTI)

Singlet exciton fission generates two triplet excitons per absorbed photon. It promises to increase the power extracted from sunlight without increasing the number of photovoltaic junctions in a solar cell. We demonstrate solar cells with an external quantum efficiency of 126% by enhancing absorption in thin films of the singlet exciton fission material pentacene. The device structure exploits the long photon dwell time at the band edge of a distributed Bragg reflector to achieve enhancement over a broad range of angles. Measuring the reflected light from the solar cell establishes a lower bound of 137% for the internal quantum efficiency.

Thompson, Nicholas J.; Congreve, Daniel N.; Baldo, Marc A., E-mail: vmenon@qc.cuny.edu, E-mail: baldo@mit.edu [Energy Frontier Research Center for Excitonics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Goldberg, David; Menon, Vinod M., E-mail: vmenon@qc.cuny.edu, E-mail: baldo@mit.edu [Department of Physics, Queens College and Graduate Center, The City University of New York, Flushing, New York 11367 (United States)

2013-12-23T23:59:59.000Z

365

Geminate and non-geminate recombination of triplet excitons formed by singlet fission  

E-Print Network [OSTI]

yields of triplet pairs. These pairs are initially entangled due to formation from a spinless singlet exciton, and serve as a unique signa- ture of the fission process [11, 12]. To minimize energy losses in this carrier multiplication process, a singlet... triplet excitons to be 60 neV. PACS numbers: 88.40.jr,71.35-y,76.70.Hb Singlet exciton fission [1, 2] is a promising route to en- hance both organic and inorganic solar cells [3#21;5], giving the potential to achieve power-conversion efficiencies well...

Bayliss, Sam L.; Chepelianskii, Alexei D.; Sepe, Alessandro; Walker, Brian J.; Ehrler, Bruno; Bruzek, Matthew J.; Anthony, John E.; Greenham, Neil C.

2014-07-04T23:59:59.000Z

366

An engineering approach to improving hospital supply chains  

E-Print Network [OSTI]

This thesis explores supply chain management practices that have been implemented, and have improved supply chains in industries outside of healthcare. The presented supply chain practices have been selected because they ...

Cheng, Scott Hsiang-Jen

2008-01-01T23:59:59.000Z

367

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

368

Criticality without Frustration for Quantum Spin-1 Chains  

E-Print Network [OSTI]

Frustration-free (FF) spin chains have a property that their ground state minimizes all individual terms in the chain Hamiltonian. We ask how entangled the ground state of a FF quantum spin-s chain with nearest-neighbor ...

Movassagh, Ramis

369

Impact of demographics on supply chain risk management practices  

E-Print Network [OSTI]

Do demographic factors play a role in the choice of supply chain risk management practices by supply chain professionals? Are there stronger relationships between certain demographic factors and supply chain risk management ...

Kanyagui, Kenneth (Kenneth K.)

2010-01-01T23:59:59.000Z

370

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

Science Journals Connector (OSTI)

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

T. Kawano; P. Talou; I. Stetcu; M.B. Chadwick

2013-01-01T23:59:59.000Z

371

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

SciTech Connect (OSTI)

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

372

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

373

Multiperiod Competitive Supply Chain Networks with Inventorying and A Transportation Network Equilibrium Reformulation Multiperiod Competitive Supply Chain Networks  

E-Print Network [OSTI]

Multiperiod Competitive Supply Chain Networks with Inventorying and A Transportation Network Equilibrium Reformulation Multiperiod Competitive Supply Chain Networks with Inventorying and A Transportation Competitive Supply Chain Networks with Inventorying and A Transportation Network Equilibrium Reformulation

Nagurney, Anna

374

U.S. Offshore Wind Manufacturing and Supply Chain Development...  

Office of Environmental Management (EM)

U.S. Offshore Wind Manufacturing and Supply Chain Development U.S. Offshore Wind Manufacturing and Supply Chain Development This report seeks to provide an organized, analytical...

375

Segmentation strategies for managing retail supply chains  

E-Print Network [OSTI]

High-technology manufacturing companies often face rapid price decline and capacity constraints. Especially in the retail side of the business where the supply chain is much longer and revenue is sometimes not recognized ...

Liang, Catherine G. (Catherine Gloria)

2011-01-01T23:59:59.000Z

376

Supply chain and the executive agenda  

E-Print Network [OSTI]

In recent years, supply chain pundits and consultants emphasized the importance of strategies such as just-in-time, lean manufacturing, off- shoring or frequent deliveries to retail outlets. However, with significant ...

Peruvankal, James Paul

2011-01-01T23:59:59.000Z

377

Economic analysis of the meat supply chain  

E-Print Network [OSTI]

and overseas animal disease outbreaks on the Korean meat supply chain. Market impacts are investigated using both forecasts and historical decomposition of price innovations based on an error correction model (ECM) of the Korean meat sector. Results indicate...

Park, Moon-Soo

2009-05-15T23:59:59.000Z

378

The supply chain response to environmental pressures  

E-Print Network [OSTI]

Understanding and shaping the relationship between supply chain management and the natural environment is critical not only to human health and the environment, but to the future success of business. While the cumulative ...

Paquette, Julie Rebecca

2006-01-01T23:59:59.000Z

379

Free Energy of Multiple Overlapping Chains  

Science Journals Connector (OSTI)

How accurate is pair additivity in describing interactions between soft polymer-based nanoparticles? Using numerical simulations we compute the free energy cost required to overlap multiple chains in the same region of space, and provide a quantitative measure of the effectiveness of pair additivity as a function of chain number and length. Our data suggest that pair additivity can indeed become quite inadequate as the chain density in the overlapping region increases. We also show that even a scaling theory based on polymer confinement can only partially account for the complexity of the problem. In fact, we unveil and characterize an isotropic to star-polymer crossover taking place for large number of chains, and propose a revised scaling theory that better captures the physics of the problem.

Katherine Klymko and Angelo Cacciuto

2011-12-27T23:59:59.000Z

380

Internal Markets for Supply Chain Capacity Allocation  

E-Print Network [OSTI]

This paper explores the possibility of solving supply chain capacity allocation problems using internal markets among employees of the same company. Unlike earlier forms of transfer pricing, IT now makes it easier for such ...

McAdams, David

2005-07-08T23:59:59.000Z

Note: This page contains sample records for the topic "fission chain reaction" 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

Ethylene detection in fruit supply chains  

Science Journals Connector (OSTI)

...Steffen Janssen and Walter Lang Ethylene detection in fruit supply chains S...and advanced warehouse management . Ethylene is a gaseous ripening phytohormone of fruits and plants. Presently, ethylene is primarily measured with stationary...

2014-01-01T23:59:59.000Z

382

Polynomial policies in supply chain networks  

E-Print Network [OSTI]

This thesis aims to solve the periodic-reviewed inventory control problem in supply chain networks with uncertain demand so as to minimize the overall cost of the system over a fixed planning time horizon. In such problems, ...

He, Liwei

2010-01-01T23:59:59.000Z

383

Better Plants Supply Chain Pilot – Overview  

Broader source: Energy.gov [DOE]

The Department of Energy (DOE) is working with Better Plants Partners to improve energy efficiency throughout their supply chains. Around 40 to 60 percent of a manufacturing company’s energy and carbon footprint can reside upstream in its supply chain—from raw materials, transport, and packaging to the energy consumed in manufacturing processes—but this number can be as high as 80 percent. Coordinating energy management practices between companies and their supply chains has the potential to significantly improve industrial energy productivity and reduce the amount of energy embedded in manufactured products. Through this Supply Chain Pilot, DOE will work with a select group of Better Plants Partners to extend the benefits of energy efficiency to their suppliers. Partners will leverage existing Better Plants Program resources and encourage suppliers to collectively set, track, and meet energy savings goals.

384

Using Simulation to Investigate Supply Chain Disruptions  

Science Journals Connector (OSTI)

Managers and researchers are coming to realize that Supply Chain Disruptions (SCDs) constitute a real and significant threat – a threat that has to be better understood. However, the challenge facing many rese...

Steven A. Melnyk; Alexander Rodrigues; Gary L. Ragatz

2009-01-01T23:59:59.000Z

385

Glossary of Nuclear Waste Terms  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

386

Reaction chemistry of cerium  

SciTech Connect (OSTI)

It is truly ironic that a synthetic organic chemist likely has far greater knowledge of the reaction chemistry of cerium(IV) than an inorganic colleague. Cerium(IV) reagents have long since been employed as oxidants in effecting a wide variety of organic transformations. Conversely, prior to the late 1980s, the number of well characterized cerium(IV) complexes did not extend past a handful of known species. Though in many other areas, interest in the molecular chemistry of the 4f-elements has undergone an explosive growth over the last twenty years, the chemistry of cerium(IV) has for the most part been overlooked. This report describes reactions of cerium complexes and structure.

NONE

1997-01-01T23:59:59.000Z

387

Photochemical reaction dynamics  

SciTech Connect (OSTI)

The purpose of the program is to develop a fundamental understanding of unimolecular and bimolecular reaction dynamics with application in combustion and energy systems. The energy dependence in ketene isomerization, ketene dissociation dynamics, and carbonyl substitution on organometallic rhodium complexes in liquid xenon have been studied. Future studies concerning unimolecular processes in ketene as well as energy transfer and kinetic studies of methylene radicals are discussed.

Moore, B.C. [Lawrence Berkeley Laboratory, Livermore, CA (United States)

1993-12-01T23:59:59.000Z

388

p¯p??¯? Reaction  

Science Journals Connector (OSTI)

The O(3,1) symmetry model is used to evaluate the differential cross section and spin correlations for the reaction p¯p??¯? at various energies. We find fairly satisfactory agreement for the differential cross section except perhaps for the 7-GeV/c data. The spin correlations for 2.19 GeV/c are found to be qualitatively consistent with experiment.

N. KWAK and M. L. NICHOLAS

1969-11-25T23:59:59.000Z

389

Release and transport of fission product cesium in the TMI-2 accident  

SciTech Connect (OSTI)

Approximately 50% of the fission product cesium was released from the overheated UO/sub 2/ fuel in the TMI-2 accident. Steam that boiled away from a water pool in the bottom of the reactor vessel transported the released fission products throughout the reactor coolant system (RCS). Some fission products passed directly through a leaking valve with steam and water into the containment structure, but most deposited on dry surfaces inside of the RCS before being dissolved or resuspended when the RCS was refilled with water. A cesium transport model was developed that extended measured cesium in the RCS back to the first day of the accident. The model revealed that approx.62% of the released /sup 137/Cs deposited on dry surfaces inside of the RCS before being slowly leached and transported out of the RCS in leaked or letdown water. The leach rates from the model agreed reasonably well with those measured in the laboratory. The chemical behavior of cesium in the TMI-2 accident agreed with that observed in fission product release tests at Oak Ridge National Laboratory (ORNL).

Lorenz, R.A.; Collins, J.L.

1986-01-01T23:59:59.000Z

390

Multiple-humped fission and fusion barriers of the heaviest elements and ellipsoidal deformations  

E-Print Network [OSTI]

leading possibly to superheavy elements, double-humped potential barriers appear for cold fusionMultiple-humped fission and fusion barriers of the heaviest elements and ellipsoidal deformations G barriers and the predicted half-lives of actinides follow the experimental results. In the fusion path

Boyer, Edmond

391

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

392

Comparison of neutron diffusion and Monte Carlo simulations of a fission wave  

E-Print Network [OSTI]

common con- figuration a fertile material, such as depleted uranium, is subjected to a fast neutron flux). The fresh fuel zone consisted of depleted uranium groups have shown that fission waves could form in uranium and potentially be used as the basis

Deinert, Mark

393

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

SciTech Connect (OSTI)

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

394

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

395

Determination of Airborne Fission Product Radioactivity using Gamma-Ray Spectrometry  

Science Journals Connector (OSTI)

... portion thereof by means of an end-window Geiger-Miiller counter or other suitable detector. Radon and thoron along with their radioactive daughter products are universally present in surface air in ... determine airborne fission product radioactivity it is necessary to differentiate it from that arising from radon and thoron daughters. The concentration of ...

P. F. GUSTAFSON; S. S. BRAR; U. C. MISHRA

1962-08-11T23:59:59.000Z

396

Fission-track analysis of detrital zircon and J. I. Garver2  

E-Print Network [OSTI]

Geology Department Olin Building, Union College Schenectady, NY, 12308-3107, USA email: garverj with various isotopic methods having reasonable high concentrations of uranium and thorium (Fig. 1). Techniques depends on individual uranium content and cooling history of a zircon grain. Fission tracks in zircon have

Paris-Sud XI, Université de

397

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

SciTech Connect (OSTI)

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

Blaise Collin

2014-09-01T23:59:59.000Z

398

Reactions of Polycarbonate with Cyclohexene Oxide and Phosphites: A Density Functional Study  

E-Print Network [OSTI]

bisphenol A polycarbonate (BPA-PC). We describe density functional (DF) calculations of the reactions of cyclohexene oxide (CHO, cyclohexane epoxide) and phosphites with chain segments of BPA- PC, with the aim to organic molecules and polymers, focusing on bisphenol A polycarbonate (BPA-PC). BPA-PC is an important

399

High-temperature reactor fuel fission product release and distribution at 1600 to 1800 degrees C  

SciTech Connect (OSTI)

The essential feature of small, modular high-temperature reactors (HTRs) is the inherent limitation in maximum accident temperature to below 1600{degrees} C combined with the ability of coated particle fuel to retain all safety-relevant fission products under these conditions. To demonstrate this ability, spherical fuel elements with modern TRISO particles are irradiated and subjected to heating tests. Even after extended heating times at 1600{degrees} C, fission product release does not exceed the already low values projected for normal operating conditions. In this paper details of fission product distribution within spherical fuel elements heated at constant temperatures of 1600, 1700, and 1800{degrees} C are presented. The measurements confirm the silicon carbide (SiC) coating layer as the most important fission product barrier up to 1800{degrees} C. If the SiC fails (or is defective), the following transport properties at 1600 to 1800{degrees} C can be observed; cesium shows the fastest release from the UO{sub 2} kernel but is highly sorbed in the buffer layer of the particle and in the matrix graphite of the sphere; strontium is retained strongly both in the UO{sub 2} kernels and in matrix graphite, but can penetrate SiC in some cases where cesium is still completely retained; only if all coating layers are breached can iodine and noble gases be released. For the first 100 h at 1600{degrees} C (enveloping all possible accident scenarios of small HTRs), these fission products are almost completely retained in the coated particles.

Schenk, W.; Nabielek, H. (Forschungszentrum Juelich, Postfach 1913, W-5170 Juelich (DE))

1991-12-01T23:59:59.000Z

400

Improving and Observing Lithiation Reactions  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

to observe these reactions in real-time as these reactions proceed. Enabling Silicon Carbide to Host Lithium In one set of measurements, they have discovered that the lithiation...

Note: This page contains sample records for the topic "fission chain reaction" 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

Kinetic Parameters Estimation in the Polymerase Chain Reaction Process Using the Genetic Algorithm  

Science Journals Connector (OSTI)

The population is generated randomly and covers the entire range of possible solutions. ... steps were applied to predict the catalyst surface coverage and the bulk concn. ... RESULTS: Using the Genetic Algorithm to find the sub-optimal solution to the optimization problem, we have estimated a set of unknown parameters describing a kinetic model of a signaling pathway in the neuronal cell. ...

Lanting Li; Chao Wang; Bo Song; Lijuan Mi; Jun Hu

2012-09-13T23:59:59.000Z

402

Theoretical and simulation tools for electron transfer and chain reactions in single walled carbon nanotubes  

E-Print Network [OSTI]

Single walled carbon nanotubes (SWNT) are cylindrical sheets of graphene whose electronic structures and diameters are determined by their chiralities. Current synthetic methods produce batches of nanotubes containing a ...

Nair, Nitish

2009-01-01T23:59:59.000Z

403

Journal of Theoretical Biology 224 (2003) 127137 Microsatellite mutations during the polymerase chain reaction  

E-Print Network [OSTI]

bands are often observed after PCR amplification. These are usually referred as stutter patterns (Perlin et al., 1994) or stutter profiles. The ARTICLE IN PRESS *Corresponding author. Tel.: +1 Elsevier Ltd. All rights reserved. doi:10.1016/S0022-5193(03)00155-3 #12;presence of stutter patterns

Sun, Fengzhu - Sun, Fengzhu

404

Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Analysis of Large Polymerases Chain Reaction Products  

SciTech Connect (OSTI)

We have attempted to expand the size range of PCR products that can be analyzed by electroscopy ionization (ESI) Fourier transformion cyclotron resonance (FTICR) mass spectrometry. The mass measurement accuracy obtained illustrates that a signel base substitution could be identified at the size of PCR product with a 7 tesla ESI-FTICR

Wunschel, David S.(BATTELLE (PACIFIC NW LAB)) [BATTELLE (PACIFIC NW LAB); Pasa Tolic, Ljiljana (BATTELLE (PACIFIC NW LAB)) [BATTELLE (PACIFIC NW LAB); Feng, Bingbing (ASSOC WESTERN UNIVERSITY) [ASSOC WESTERN UNIVERSITY; Smith, Richard D.(BATTELLE (PACIFIC NW LAB)) [BATTELLE (PACIFIC NW LAB)

2000-04-01T23:59:59.000Z

405

Three Dimensional Simulation of Rayleigh-Bénard Convection for Rapid Microscale Polymerase Chain Reaction  

E-Print Network [OSTI]

Rayleigh-Bénard convection has been extensively studied in literature owing to its ubiquitous nature. However, most of the studies have been confined to geometries where the aspect ratio of the cylinder was less than 1. Here we study the motion...

Muddu, Radha Malini Gowri

2012-02-14T23:59:59.000Z

406

DSS-mediated Inhibition of Quantitative Real-time Polymerase Chain Reaction  

E-Print Network [OSTI]

........................................................................................................3 2 Real-Time PCR Graph ...........................................................................................4 3 Fecal Sample Collection Timeline .........................................................................6 4 Purification... 280 ratio between 1.8-1.9 indicates highly purified DNA; whereas, a ratio less than 1.8 indicates protein contamination (2). Unfortunately, co-purification of acidified polysaccharides, such as DSS cannot be detected using a spectrophotometrically...

Kaur, Jaspreet

2011-08-04T23:59:59.000Z

407

Reactions of Ar40 with Dy160, Dy164, and Yb174  

Science Journals Connector (OSTI)

Excitation functions for nuclear reactions induced by Ar40 ions were measured for the reactions Dy164(Ar40,xn)Po204-x, Dy160(Ar40,xn)Po200-x, Yb174(Ar40,xn)Ra214-x, and Yb174(Ar40,pxn)Fr213-x. For all of the systems studied, the (Ar,xn) reactions only make up a small part of the total reaction cross section of ?2 b; the largest cross sections encountered in each system were (at the peaks of the respective excitation functions) 30 mb for Dy164(Ar,5n), 10 mb for Dy160(Ar,4n), and 5 mb for Yb174(Ar,4n-5n). The probabilities Pxn of neutron emission in the compound systems Po204 and Po200 were found to be very different, with respective maximum probabilities for the emission of four, five, and six neutrons of 0.064, 0.035, and 0.016 for Po204, and 0.010, 0.0025, and 0.0003 for Po200. Calculations performed with a statistical-model code, which includes angular-momentum effects and fission competition, are able to reproduce the shapes and magnitudes of the experimental excitation functions, although there is a systematic energy difference, ?10 MeV, between theory and the data. These model-dependent analyses describe in detail how the particle evaporation and fission deexcitation modes vary with angular momentum and excitation energy. The observed large differences in Pxn values for Po204 and Po200 are seen to arise from the small difference, ?1.2 MeV, between the values of Sn-Bf, the difference of neutron-separation and fission-barrier energies, in each compound system.NUCLEAR REACTIONS Dy160(Ar40,xn)Po200-x, Dy164(Ar40,xn)Po204-x, Yb174(Ar40,xn)Ra214-x, and Yb174(Ar40,pxn)Fr213-x. E=160-270 MeV; measured ?(E) for product nuclei that are ?-particle radioactive; compared with statistical-model calculations.

Y. LeBeyec; R. L. Hahn; K. S. Toth; R. Eppley

1976-09-01T23:59:59.000Z

408

Recent developments of the cascade-exciton model of nuclear reactions  

SciTech Connect (OSTI)

Recent developments of the Cascade-Exciton Model (CEM) of nuclear reactions are described. The improved cascade-exciton model as implemented in the code CEM97 differs from the CEM95 version by incorporating new approximations for the elementary cross sections used in the cascade, using more precise values for nuclear masses and pairing energies, using corrected systematics for the level-density parameters, and several other refinements. We have improved algorithms used in many subroutines, decreasing the computing time by up to a factor of 6 for heavy targets. We describe a number of further improvements and changes to CEM97, motivated by new data on isotope production measured at GSI. This leads us to CEM2k, a new version of the CEM code. CEM2k has a longer cascade stage, less preequilibrium emission, and evaporation from more highly excited compound nuclei compared to earlier versions. CEM2k also has other improvements and allows us to better model neutron, radionuclide, and gas production in ATW spallation targets. The increased accuracy and predictive power of the code CEM2k are shown by several examples. Further necessary work is outlined. KEYWORDS: Intranuclear cascade, preequilibrium, evaporation, and fission reactions, Monte Carlo simulations, cascade-exciton model, particle spectra, spallation and fission cross sections, GSI data

Mashnik, S. G. (Stepan G.); Sierk, A. J. (Arnold J.)

2001-01-01T23:59:59.000Z

409

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

410

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

411

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

412

Chain elongation with reactor microbiomes: upgrading dilute ethanol to medium-chain carboxylates  

E-Print Network [OSTI]

through a reversed b-oxidation pathway.6­8 This bacterium uses ethanol as a source of carbon, energy for elongation by C. kluyveri, one molecule of ethanol is oxidized to acetic acid for metabolic energy.6 OpenChain elongation with reactor microbiomes: upgrading dilute ethanol to medium-chain carboxylates

Angenent, Lars T.

413

Molecular dynamics simulation of chains mobility in polyethylene crystal  

E-Print Network [OSTI]

The mobility of polymer chains in perfect polyethylene (PE) crystal was calculated as a function of temperature and chain length through Molecular dynamics (MD) in united atom approximation. The results demonstrate that the chain mobility drastically increases in the vicinity of the phase transition from the orthorhombic to quasi-hexagonal phase. In the quasi-hexagonal phase, the chain mobility is almost independent on temperature and inversely proportional to the chain length.

V. I. Sultanov; V. V. Atrazhev; D. V. Dmitriev; S. F. Burlatsky

2014-01-17T23:59:59.000Z

414

Free-radical reactions in glow and explosion of carbon monoxide-oxygen mixtures  

SciTech Connect (OSTI)

Examination of published compilations of rate coefficients of free-radical reactions yields reactions that are associated with chain branching in mixtures of CO and O/sub 2/ and small quantities of hydrogen or water vapor. The complete mechanism included diffusion of HO/sub 2/ radicals to the vessel wall and their adsorption and reaction at the surface. This mechanism is applied to the data of E.J. Buckler and R.G.W. Norrish on the branched-chain explosion of CO-O/sub 2/ mixtures containing H/sub 2/ in the order of 1 mm Hg. Substantial agreement is found between theory and experiment. Further, the mechanism is applied to experiments of Bond, Gray, and Griffiths with an H/sub 2/ content of 0.01-0.05 mm Hg. By specifying details of the adsorption and surface reaction of HO/sub 2/ on the basis of Langmuir's adsorption the phenomenon of flow is explained and the regions of slow reaction, glow, and explosion are described in accord with the experimental data. It is confirmed that the reaction between CO and O/sub 2/ requires the presence of a hydrogenous compound such as H/sub 2/, H/sub 2/O, CH/sub 4/, etc., and that ''dry'' homogenous reaction is not possible except at very high temperatures.

Von Elbe, G.; Lewis, B.

1986-02-01T23:59:59.000Z

415

Nucleus-nucleus cold fusion reactions analyzed with the l-dependent 'fusion by diffusion' model  

SciTech Connect (OSTI)

We present a modified version of the Fusion by Diffusion (FBD) model aimed at describing the synthesis of superheavy nuclei in cold fusion reactions, in which a low excited compound nucleus emits only one neutron. The modified FBD model accounts for the angular momentum dependence of three basic factors determining the evaporation residue cross section: the capture cross section {sigma}{sub cap}(l), the fusion probability P{sub fus}(l), and the survival probability P{sub surv}(l). The fusion hindrance factor, the inverse of P{sub fus}(l), is treated in terms of thermal fluctuations in the shape degrees of freedom and is expressed as a solution of the Smoluchowski diffusion equation. The l dependence of P{sub fus}(l) results from the l-dependent potential energy surface of the colliding system. A new parametrization of the distance of starting point of the diffusion process is introduced. An analysis of a complete set of 27 excitation functions for production of superheavy nuclei in cold fusion reactions, studied in experiments at GSI Darmstadt, RIKEN Tokyo, and LBNL Berkeley, is presented. The FBD model satisfactorily reproduces shapes and absolute cross sections of all the cold fusion excitation functions. It is shown that the peak position of the excitation function for a given 1n reaction is determined by the Q value of the reaction and the height of the fission barrier of the final nucleus. This fact could possibly be used in future experiments (with well-defined beam energy) for experimental determination of the fission barrier heights.

Cap, T.; Siwek-Wilczynska, K.; Wilczynski, J. [Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Hoza 69, PL-00-681 Warsaw (Poland); Andrzej Soltan Institute for Nuclear Studies, PL-05-400 Otwock-Swierk (Poland)

2011-05-15T23:59:59.000Z

416

Critical dynamics of nonperiodic Ising chains  

Science Journals Connector (OSTI)

The critical dynamics of the nonperiodic ferromagnetic Ising chains with two different coupling constants (J1>J2>0) arranged in nonperiodic sequences are studied by trace map method. For Glauber dynamics, it is found that the dynamical critical exponent z=1+J1/J2 for the Fibonacci, general Fibonacci (e.g., silver-mean, copper-mean), and period-doubling ferromagnetic Ising chains. The applicability of the trace map method and the origin of the nonuniversality are briefly discussed.

Peiqing Tong

1997-08-01T23:59:59.000Z

417

Peppytides: Interactive Models of Polypeptide Chains  

ScienceCinema (OSTI)

Peppytides are scaled, 3D-printed models of polypeptide chains that can be folded into accurate protein structures. Designed and created by Berkeley Lab Researcher, Promita Chakraborty, and Berkeley Lab Senior Scientist, Dr. Ron Zuckermann, Peppytides are accurate physical models of polypeptide chains that anyone can interact with and fold intro various protein structures - proving to be a great educational tool, resulting in a deeper understanding of these fascinating structures and how they function. Build your own Peppytide model and learn about how nature's machines fold into their intricate architectures!

Zuckermann, Ron; Chakraborty, Promita; Derisi, Joe

2014-10-28T23:59:59.000Z

418

Peppytides: Interactive Models of Polypeptide Chains  

SciTech Connect (OSTI)

Peppytides are scaled, 3D-printed models of polypeptide chains that can be folded into accurate protein structures. Designed and created by Berkeley Lab Researcher, Promita Chakraborty, and Berkeley Lab Senior Scientist, Dr. Ron Zuckermann, Peppytides are accurate physical models of polypeptide chains that anyone can interact with and fold intro various protein structures - proving to be a great educational tool, resulting in a deeper understanding of these fascinating structures and how they function. Build your own Peppytide model and learn about how nature's machines fold into their intricate architectures!

Zuckermann, Ron; Chakraborty, Promita; Derisi, Joe

2014-01-21T23:59:59.000Z

419

Coadsorption as a probe of mechanism: cyclic sulfides and straight chain thiols on Mo(110)  

SciTech Connect (OSTI)

The authors reported that tetrahydrothiophene and trimethylene sulfide undergo desulfurization on Mo(110) to form gaseous alkanes and alkenes in a temperature-programmed reaction experiment. In both cases, straight chain alkane evolution preceded alkene evolution. They proposed that the intermediate leading to straight chain alkanes and alkenes from these two cyclic sulfides is a surface thiolate. The thiolate undergoes competitive C/sub 1/-hydrogenation to alkane and C/sub 2/-dehydrogenation to alkene, depending on the surface hydrogenation concentration. They report here that coadsorbed cyclic sulfides C/sub n/H/sub 2n/S (n = 3, 4) and linear thiols C/sub m/H/sub 2m+1/SH(m = 2, 3, 4) react during a temperature-programmed reaction experiment to form alkanes C/sub n/H/sub 2n+2/ and C/sub m/H/sub 2m+2/ at exactly the same temperature. These experiments lend powerful support to their proposal that cyclic sulfides and straight chain thiols react on Mo(110) by way of a thiolate intermediate.

Roberts, J.T.; Friend, C.M.

1987-07-08T23:59:59.000Z

420

Kinetic and mechanistic studies of free-radical reactions in combustion  

SciTech Connect (OSTI)

Combustion is driven by energy-releasing chemical reactions. Free radicals that participate in chain reactions carry the combustion process from reactants to products. Research in chemical kinetics enables us to understand the microscopic mechanisms involved in individual chemical reactions as well as to determine the rates at which they proceed. Both types of information are required for an understanding of how flames burn, why engines knock, how to minimize the production of pollutants, and many other important questions in combustion. In this program the authors emphasize accurate measurements over wide temperature ranges of the rates at which ubiquitous free radicals react with stable molecules. The authors investigate a variety of OH, CN, and CH + stable molecule reactions important to fuel conversion, emphasizing application of the extraordinarily precise technique of laser photolysis/continuous-wave laser-induced fluorescence (LP/cwLIF). This precision enables kinetic measurements to serve as mechanistic probes. Since considerable effort is required to study each individual reaction, prudent selection is critical. Two factors encourage selection of a specific reaction: (1) the rates and mechanisms of the subject reaction are required input to a combustion model; and (2) the reaction is a chemical prototype which, upon characterization, will provide fundamental insight into chemical reactivity, facilitate estimation of kinetic parameters for similar reactions, and constrain and test the computational limits of reaction-rate theory. Most studies performed in this project satisfy both conditions.

Tully, F.P. [Sandia National Laboratories, Livermore, CA (United States)

1993-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "fission chain reaction" 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

Fission-fusion sociality in dusky dolphins (Lagenorhynchus obscurus), with comparisons to other dolphins and great apes  

E-Print Network [OSTI]

I examined fission-fusion sociality in dusky dolphins (Lagenorhynchus obscurus), and investigated aspects of social convergence between dolphins and great apes. I used boat-based group focal follows and photo-identification to collect data...

Pearson, Heidi Christine

2008-10-10T23:59:59.000Z

422

Concentrations of Naturally Occuring Radionuclides and Fission Products in Brick Samples Fabricated and Used in and Around Greater Dhaka City  

Science Journals Connector (OSTI)

...Radiation Protection Dosimetry Article Concentrations of Naturally Occuring Radionuclides and Fission Products in Brick Samples...measures to minimise the harmful effects of ionising radiation. The radium equivalent activity concentrations......

S. Roy; M.S. Alam; F.K. Miah; B. Alam

2000-04-01T23:59:59.000Z

423

Some Reactions of Formamidines  

E-Print Network [OSTI]

Hs i HHCeH*0CHaCeH5 I COOCaHs COOCaHs * IfHaCeHo-OCHaCeHs •23- Analysis: Hitrogen determination "by Kjeldahl method. II 12.5047 12.3667 .1380 30.52 29.84 .68 47.92 Co. 46.00 49.24 .04 2.84 45.96 46.40 normality of acid .1105 Ratio... colored substance. M.P. 95° - 96° C. Reaction: CHa CO CHa CO I' >. 2fCeH*0CHaCeHs ' CHa * HC - C s CHMC6H*0CHaCeHs l v HHCeH*0CHaCeH5 » + EEaCeH*OCHaCdHs COOCaHs COOCaHs This product may be called p-benzyl-oxy-anilidomethyleneaceto- aoetic ethyl...

Malleis, Otto Oscar

1913-05-15T23:59:59.000Z

424

Laser induced nuclear reactions  

SciTech Connect (OSTI)

Dramatic improvements in laser technology since 1984 have revolutionised high power laser technology. Application of chirped-pulse amplification techniques has resulted in laser intensities in excess of 10{sup 19} W/cm{sup 2}. In the mid to late eighties, C. K. Rhodes and K. Boyer discussed the possibility of shining laser light of this intensity onto solid surfaces and to cause nuclear transitions. In particular, irradiation of a uranium target could induce electro- and photofission in the focal region of the laser. In this paper it is shown that {mu}Ci of {sup 62}Cu can be generated via the ({gamma},n) reaction by a laser with an intensity of about 10{sup 19} Wcm{sup -2}.

Ledingham, Ken; McCanny, Tom; Graham, Paul; Fang Xiao; Singhal, Ravi; Magill, Joe; Creswell, Alan; Sanderson, David; Allott, Ric; Neely, David; Norreys, Peter; Santala, Marko; Zepf, Matthew; Watts, Ian; Clark, Eugene; Krushelnick, Karl; Tatarakis, Michael; Dangor, Bucker; Machecek, Antonin; Wark, Justin [Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, Scotland (United Kingdom); European Commission, Institute for Transuranic Elements, Karlsruhe, Postfach 2340, D-76125 (Germany); Scottish Universities Research and Reactor Centre, East Kilbride, Glasgow G75 0QU (United Kingdom); Rutherford Appleton Laboratory, Chilton, Didcot (United Kingdom); Blackett Laboratory, Imperial College, London SW7 2BZ (United Kingdom); Clarendon Laboratory, Department of Physics, University of Oxford, OX1 3PU (United Kingdom)

1998-12-16T23:59:59.000Z

425

Reactions of Methylene Hydrogen  

E-Print Network [OSTI]

. 132 Claisen. 17. reaching with either one or two moles of the ester. The reaction may he considered to go on as follows: COOCeHs COOCeHs r • / 1 CHeCHfO + He| 0 - CHsCH = C \\ I COOCaHs COOCeHs aoetal malonic ester. Then a seoond molectte...COH : CHXCOOCBHB CHaCOH : CXCOOC«Hs + Ua * CHeC : CZCOOCaHs I Ola CHaC : CXCOOCeHa + YI m CHa C • CXYCOOCaHa I I I Ola Ola - CHsCOCXYCOOCeHs The sodium salt exists in the enol form. The alkyl iodide adds direotly at the double bond and then splitts off a...

Griffin, E. L.

1912-05-15T23:59:59.000Z

426

Structure of the second RRM domain of Nrd1, a fission yeast MAPK target RNA binding protein, and implication for its RNA recognition and regulation  

SciTech Connect (OSTI)

Highlights: •Solution structure of the second RRM of Nrd1 was determined. •RNA binding site of the second RRM was estimated. •Regulatory mechanism of RNA binding by phosphorylation is discussed. -- Abstract: Negative regulator of differentiation 1 (Nrd1) is known as a negative regulator of sexual differentiation in fission yeast. Recently, it has been revealed that Nrd1 also regulates cytokinesis, in which physical separation of the cell is achieved by a contractile ring comprising many proteins including actin and myosin. Cdc4, a myosin II light chain, is known to be required for cytokinesis. Nrd1 binds and stabilizes Cdc4 mRNA, and thereby suppressing the cytokinesis defects of the cdc4 mutants. Interestingly, Pmk1 MAPK phosphorylates Nrd1, resulting in markedly reduced RNA binding activity. Furthermore, Nrd1 localizes to stress granules in response to various stresses, and Pmk1 phosphorylation enhances the localization. Nrd1 consists of four RRM domains, although the mechanism by which Pmk1 regulates the RNA binding activity of Nrd1 is unknown. In an effort to delineate the relationship between Nrd1 structure and function, we prepared each RNA binding domain of Nrd1 and examined RNA binding to chemically synthesized oligo RNA using NMR. The structure of the second RRM domain of Nrd1 was determined and the RNA binding site on the second RRM domain was mapped by NMR. A plausible mechanism pertaining to the regulation of RNA binding activity by phosphorylation is also discussed.

Kobayashi, Ayaho; Kanaba, Teppei [Graduate School of Science and Engineering, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji 192-0397 (Japan)] [Graduate School of Science and Engineering, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji 192-0397 (Japan); Satoh, Ryosuke [Institute of Microbial Chemistry, 3-14-23 Kamiosaki, Shinagawa-ku 141-0021, Tokyo (Japan)] [Institute of Microbial Chemistry, 3-14-23 Kamiosaki, Shinagawa-ku 141-0021, Tokyo (Japan); Fujiwara, Toshinobu [Institute of Microbial Chemistry, 3-14-23 Kamiosaki, Shinagawa-ku 141-0021, Tokyo (Japan) [Institute of Microbial Chemistry, 3-14-23 Kamiosaki, Shinagawa-ku 141-0021, Tokyo (Japan); Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku,Nagoya 467-8603 (Japan); Ito, Yutaka [Graduate School of Science and Engineering, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji 192-0397 (Japan)] [Graduate School of Science and Engineering, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji 192-0397 (Japan); Sugiura, Reiko [Laboratory of Molecular Pharmacogenomics, School of Pharmaceutical Sciences, Kinki University, 3-4-1 Kowakae, Higashi-Osaka 577-8502 (Japan)] [Laboratory of Molecular Pharmacogenomics, School of Pharmaceutical Sciences, Kinki University, 3-4-1 Kowakae, Higashi-Osaka 577-8502 (Japan); Mishima, Masaki, E-mail: mishima-masaki@tmu.ac.jp [Graduate School of Science and Engineering, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji 192-0397 (Japan)] [Graduate School of Science and Engineering, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji 192-0397 (Japan)

2013-07-19T23:59:59.000Z

427

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

SciTech Connect (OSTI)

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

428

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

SciTech Connect (OSTI)

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

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

2011-07-01T23:59:59.000Z

429

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

430

Safety and power multiplication aspects of mirror fusion-fission hybrids  

SciTech Connect (OSTI)

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

431

Fusion-Fission Research Facility (FFRF) as a Practical Step Toward Hybrids  

SciTech Connect (OSTI)

The project of ASIPP (with PPPL participation), called FFRF, (R/a=4/1 m/m, Ipl=5 MA, Btor=4-6 T, PDT=50-100 MW, Pfission=80-4000 MW, 1 m thick blanket) is outlined. FFRF stands for the Fusion-Fission Research Facility with a unique fusion mission and a pioneering mission of merging fusion and fission for accumulation of design, experimental, and operational data for future hybrid applications. The design of FFRF will use as much as possible the EAST and ITER design experience. On the other hand, FFRF strongly relies on new, Lithium Wall Fusion plasma regimes, the development of which has already started in the US and China.

L. Zakharov, J. Li and Y. Wu

2010-11-18T23:59:59.000Z

432

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

SciTech Connect (OSTI)

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

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

1991-01-01T23:59:59.000Z

433

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

SciTech Connect (OSTI)

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

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

1991-12-31T23:59:59.000Z

434

A novel series of vectors for chromosomal integration in fission yeast  

SciTech Connect (OSTI)

A series of fission yeast targeting vectors that can be used for wild-type strains having no selectable markers have been designed. The functions of one of three marker genes, lys1{sup +}, arg1{sup +}, and his3{sup +}, involved in amino acid synthesis, are impaired by integration of the fragments generated by restriction enzyme digestion of the plasmids. Successful integration of the fragments into the targeted loci can be readily verified by their requirement for amino acids, or by the PCR diagnostic analysis. Since these selection markers are not used commonly in fission yeast, these plasmids are likely to facilitate studies that require the co-expression of genes such as co-localization and co-immunoprecipitation experiments, by employing them in combination with most of the previously reported markers.

Matsuyama, Akihisa [Chemical Genetics Laboratory, RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198, CREST, JST, Saitama 332-0012 (Japan)], E-mail: akihisa@riken.jp; Shirai, Atsuko; Yoshida, Minoru [Chemical Genetics Laboratory, RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198, CREST, JST, Saitama 332-0012 (Japan)

2008-09-19T23:59:59.000Z

435

Effects of simulated fission products on the mechnical properties of zircaloy-2  

SciTech Connect (OSTI)

Room temperature tensile tests were carried out on Zircaloy-2 specimens exposed to the simulated fission products tellurium, selenium, bromine, iodine, cadmium, indium, antimony, and molybdenum up to 3.6 Ms (1000 h) in the temperature range from 623 to 973 K. Exposure at 623 or 773 K did not significantly affect either strength or elongation values of Zircaloy-2, irrespective of the chemical environment. All specimens showed high reduction of area and ductile fracture morphology. Exposure to these elements at 973 K, on the other hand, results in a general reduction of the tensile properties at room temperature; in fact, iodine, bromine, and molybdenum cause nonductile fracture with little or no reduction of area. These results are significant, since molybdenum is an abundant fission product.

Kohli, R.; Holub, F.

1980-04-01T23:59:59.000Z

436

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

437

Critical dynamics of the open Ising chain  

Science Journals Connector (OSTI)

The one-dimensional ferromagnetic Ising model with open boundary conditions within the Glauber dynamics is studied. From the behavior of the order parameter, the explicit scaling form of the relaxation time is obtained. For finite systems, the dynamical critical exponent is z=1, in contrast to the value of the infinite open chain (z=2).

J. Kamphorst Leal da Silva; Adriana G. Moreira; M. Silvério Soares; F. C. Sá Barreto

1995-10-01T23:59:59.000Z

438

The Value Chain of Colorado Agriculture  

E-Print Network [OSTI]

The Value Chain of Colorado Agriculture Gregory Graff, Ryan Mortenson, Rebecca Goldbach, Dawn of Agricultural and Resource Economics, College of Agricultural Sciences, and the Office of Engagement Colorado by support from the Colorado Department of Agriculture and the Colorado State University Office of Engagement

439

The Value Chain of Colorado Agriculture  

E-Print Network [OSTI]

The Value Chain of Colorado Agriculture Gregory Graff, Ryan Mortenson, Rebecca Goldbach, Dawn of Agricultural and Resource Economics, College of Agricultural Sciences, and the Office of Engagement Colorado the Colorado Department of Agriculture and the Colorado State University Office of Engagement. The authors

Stephens, Graeme L.

440

Engaging Supply Chains in Climate Change  

Science Journals Connector (OSTI)

Suppliers are increasingly being asked to share information about their vulnerability to climate change and their strategies to reduce greenhouse gas emissions. Their responses vary widely. We theorize and empirically identify several factors associated ... Keywords: econometric analysis, empirical research, environmental operations, quality management, risk management, supply chain management, sustainable operations

Chonnikarn Fern Jira; Michael W. Toffel

2013-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "fission chain reaction" 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

Remote quality monitoring in the banana chain  

Science Journals Connector (OSTI)

...bypassed the warehouse handling and directly transported...chain for bananas as applied in our field tests...prioritized for port handling. Palletloads which...development and monitoring technologies have to go hand...analyser; Control in applied Physiology (CP...i) Experimental procedure for banana storage...

2014-01-01T23:59:59.000Z

442

Supply Chain Risk Management (SCRM) Awareness Toolkit  

Broader source: Energy.gov [DOE]

DOE-developed toolkit contains SCRM awareness material that informs the general DOE user of basic SCRM terms and concepts. Supply chain is how organizations, people, technology, activities, information and resources are involved in developing, producing, or delivering a product or service.

443

The glass pipeline: increasing supply chain  

Science Journals Connector (OSTI)

Based upon a year-long project carried out at a UK luxury carmaker, this paper argues for a supply chain where upstream synchronisation is improved by the use of primary demand to calculate second and third-tier component requirements. The paper formulates a case for further developments to the established automotive ''sequenced'' supply model, where synchronised and lean first tiers are frequently supplied by lower tiers that carry higher stock levels, and whose production patterns bear little relationship to primary demand. The proposed development aims to enhance synchronisation of the lower portion of the chain that is outside the reach of full ''sequenced'' supply, but, within the time horizon of the vehicle manufacturers firm build schedule. This ''synchronised'' portion of the chain is achieved through increased information transparency, and hence the term ''glass pipeline'' has been used as a label for the proposed model. A case study illustration of the concept is presented, and a prototype is tested with a series of trials across a four-tier supply chain. A method for measuring synchronisation is developed, and associated business benefits are calculated in order to evaluate the model.

Julian Coleman; Andrew Lyons; Dennis Kehoe

2004-01-01T23:59:59.000Z

444

Modeling requirements for full-scope reactor simulators of fission-product transport during severe accidents  

SciTech Connect (OSTI)

This paper describes in the needs and requirements to properly and efficiently model fission product transport on full scope reactor simulators. Current LWR simulators can be easily adapted to model severe accident phenomena and the transport of radionuclides. Once adapted these simulators can be used as a training tool during operator training exercises for training on severe accident guidelines, for training on containment venting procedures, or as training tool during site wide emergency training exercises.

Ellison, P.G.; Monson, P.R. (Westinghouse Savannah River Co., Aiken, SC (United States)); Mitchell, H.A. (Concord Associates, Inc., Knoxville, TN (United States))

1990-01-01T23:59:59.000Z

445

Modeling requirements for full-scope reactor simulators of fission-product transport during severe accidents  

SciTech Connect (OSTI)

This paper describes in the needs and requirements to properly and efficiently model fission product transport on full scope reactor simulators. Current LWR simulators can be easily adapted to model severe accident phenomena and the transport of radionuclides. Once adapted these simulators can be used as a training tool during operator training exercises for training on severe accident guidelines, for training on containment venting procedures, or as training tool during site wide emergency training exercises.

Ellison, P.G.; Monson, P.R. [Westinghouse Savannah River Co., Aiken, SC (United States); Mitchell, H.A. [Concord Associates, Inc., Knoxville, TN (United States)

1990-12-31T23:59:59.000Z

446

Total and spontaneous fission half-lives of the americium and curium nuclides  

SciTech Connect (OSTI)

The total half-life and the half-life for spontaneous fission are evaluated for the various long-lived nuclides of interest. Recommended values are presented for /sup 241/Am, /sup 242m/Am, /sup 243/Am, /sup 242/Cm, /sup 243/Cm, /sup 244/Cm, /sup 245/Cm, /sup 246/Cm, /sup 247/Cm, /sup 248/Cm, and /sup 250/Cm. The uncertainties are provided at the 95% confidence limit for each of the recommended values.

Holden, N.E.

1984-01-01T23:59:59.000Z

447

Population of superdeformed bands, the competition with fission, and the barrier between normal and superdeformed states  

SciTech Connect (OSTI)

In this paper we report on the entry points leading to superdeformed (SD) as well as normal bands. We find that, compared to normal bands, the entry spins for the SD bands are about 9 {h bar} higher, and the entry excitation energy 1--3 MeV colder. We also conclude that population of the SD bands represents successful competition against fission. SD bands in both the Dy and Hg regions are considered.

Khoo, T.L.; Janssens, R.V.F.; Moore, E.F.; 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, P.; 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

448

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

449

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

SciTech Connect (OSTI)

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

450

Fusion by diffusion. II. Synthesis of transfermium elements in cold fusion reactions  

Science Journals Connector (OSTI)

We describe a method of estimating cross sections for the synthesis of very heavy nuclei by the fusion of two lighter ones. The cross section is considered to be the product of three factors: the cross section for the projectile to overcome the Coulomb barrier, the probability that the resulting composite nucleus reaches the compound nucleus configuration by a shape fluctuation treated as a diffusion of probability in one dimension, and the probability that the excited compound nucleus survives fission. Semi-empirical formulas for the mean Coulomb barrier height and its distribution around the mean are constructed. After overcoming the Coulomb barrier the system is assumed to be injected into an “asymmetric fission valley” by a rapid growth of the neck between the target and projectile at approximately frozen asymmetry and elongation. Diffusion in the elongation coordinate in this valley can occasionally bring the system over the saddle separating the injection point from the compound nucleus configuration. This is the stage that accounts for the hindrance to fusion observed for very heavy reacting systems. The competition between deexcitation of the compound nucleus by neutron emission and fission is treated by standard methods, but an interesting insight allows one to predict in an elementary way the location of the maximum in the resulting excitation function. Adjusting one parameter in the theory causes the calculated peak cross sections to agree within about a factor of 2 or so with 12 measured or estimated values for “cold” one-neutron-out reactions where targets of Pb208 and Bi209 are bombarded with projectiles ranging from Ca48 to Zn70. The centroids of the excitation functions agree with theory to within 1 or 2 MeV for the six cases where they have been determined, and their widths are reproduced. “Hot” fusion reactions, where several neutrons are emitted, are not treated, except that a comparison is made between the hindrance factors in cold and hot reactions to make elements with atomic numbers 112 to 118. The calculated diffusive hindrances in the hot reactions are less unfavorable by 4 to 5 orders of magnitude.

W. J. ?wi?tecki; K. Siwek-Wilczy?ska; J. Wilczy?ski

2005-01-07T23:59:59.000Z

451

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

452

Critical insight into the influence of the potential energy surface on fission dynamics  

SciTech Connect (OSTI)

The present work is dedicated to a careful investigation of the influence of the potential energy surface on the fission process. The time evolution of nuclei at high excitation energy and angular momentum is studied by means of three-dimensional Langevin calculations performed for two different parametrizations of the macroscopic potential: the Finite Range Liquid Drop Model (FRLDM) and the Lublin-Strasbourg Drop (LSD) prescription. Depending on the mass of the system, the topology of the potential throughout the deformation space of interest in fission is observed to noticeably differ within these two approaches, due to the treatment of curvature effects. When utilized in the dynamical calculation as the driving potential, the FRLDM and LSD models yield similar results in the heavy-mass region, whereas the predictions can be strongly dependent on the Potential Energy Surface (PES) for medium-mass nuclei. In particular, the mass, charge, and total kinetic energy distributions of the fission fragments are found to be narrower with the LSD prescription. The influence of critical model parameters on our findings is carefully investigated. The present study sheds light on the experimental conditions and signatures well suited for constraining the parametrization of the macroscopic potential. Its implication regarding the interpretation of available experimental data is briefly discussed.

Mazurek, K. [Niewodniczanski Institute of Nuclear Physics, PAN, 31-342 Krakow (Poland); Grand Accelerateur National d'Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, F-14076 Caen (France); Schmitt, C.; Wieleczko, J. P.; Ademard, G. [Grand Accelerateur National d'Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, F-14076 Caen (France); Nadtochy, P. N. [Omsk State University, Department of Theoretical Physics, 644077 Omsk (Russian Federation)

2011-07-15T23:59:59.000Z

453

Neutron capture and neutron-induced fission experiments on americium isotopes with DANCE  

SciTech Connect (OSTI)

Neutron capture cross section data on Am isotopes were measured using the Detector for Advanced Neutron Capture Experiments (DANCE) at Los Alamos National Laboratory. The neutron capture cross section was determined for {sup 241}Am for neutron energies between thermal and 320 keV. Preliminary results were also obtained for {sup 243}Am for neutron energies between 35 eV and 200 keV. The results on concurrent neutron-induced fission and neutron-capture measurements on {sup 242m}Am will be presented, where the fission events were actively triggered during the experiments. In these experiments, the Parallel-Plate Avalanche Counter (PPAC) detector that surrounds the target located in the center of the DANCE array was used as a fission-tagging detector to separate (n,{gamma}) from (n,f) events. The first evidence of neutron capture on {sup 242m}Am in the resonance region in between 2 and 9 eV of the neutron energy was obtained.

Jandel, Marian [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

454

Neutron capture and neutron-induced fission experiments on americium isotopes with DANCE  

SciTech Connect (OSTI)

Neutron capture cross section data on Am isotopes were measured using the Detector for Advanced Neutron Capture Experiments (DANCE) at Los Alamos National Laboratory. The neutron capture cross section was determined for {sup 241}Am for neutron energies between thermal and 320 keV. Preliminary results were also obtained for {sup 243}Am for neutron energies between 10 eV and 250 keV. The results on concurrent neutron-induced fission and neutron-capture measurements on {sup 242m}Am will be presented where the fission events were actively triggered during the experiments. In these experiments, a Parallel-Plate Avalanche Counter (PPAC) detector that surrounds the target located in the center of the DANCE array was used as a fission-tagging detector to separate (n,{gamma}) events from (n,f) events. The first direct observation of neutron capture on {sup 242m}Am in the resonance region in between 2 and 9 eV of the neutron energy was obtained.

Jandel, M.; Bredeweg, T. A.; Fowler, M. M.; Bond, E. M.; Couture, A.; Haight, R. C.; Keksis, A. L.; O'Donnell, J. M.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wilhelmy, J. B.; Wouters, J. M. [Los Alamos National Laboratory, Los Alamos, NM, 87545 (United States); Stoyer, M. A.; Wu, C. Y.; Becker, J. A.; Haslett, R. J.; Henderson, R. A. [Lawrence Livermore National Laboratory, Livermore, CA, 94550 (United States)

2009-01-28T23:59:59.000Z

455

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

SciTech Connect (OSTI)

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

Van der Ven, Anton; Was, Gary; Wang, Lumin; Taheri, Mitra

2014-07-07T23:59:59.000Z

456

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

SciTech Connect (OSTI)

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

457

Nuclear Reactions & Scaling Arguments 11 October 2011  

E-Print Network [OSTI]

Nuclear Reactions & Scaling Arguments 11 October 2011 Goals · Review nuclear reaction rates · Practice using scaling arguments Nuclear Reactions 1. Consider the simple reaction A k1 ---- B k2 ---- C = 3. #12;nuclear reactions & scaling arguments 2 3. Frequently, we approximate nuclear reaction rates

Militzer, Burkhard

458

Theory of Polymer Chains in Poor Solvent: Single-Chain Structure, Solution Thermodynamics and Theta Point  

E-Print Network [OSTI]

Using the language of the Flory chi parameter, we develop a theory that unifies the treatment of the single-chain structure and the solution thermodynamics of polymers in poor solvents. The structure of a globule and its melting thermodynamics is examined using the self-consistent filed theory. Our results show that the chain conformation involves three states prior to the globule-to-coil transition: the fully-collapsed globule, the swollen globule and the molten globule, which are distinguished by the core density and the interfacial thickness. By examining the chain-length dependence of the melting of the swollen globule, we find universal scaling behavior in the chain properties near the Theta point. The information of density profile and free energy of the globule is used in the dilute solution thermodynamics to study the phase equilibrium of polymer solution. Our results show different scaling behavior of the solubility of polymers in the dilute solution compared to the F-H theory, both in the chi dependence and the chain-length dependence. From the perspectives of single chain structure and solution thermodynamics, our results verifies the consistency of the Theta point defined by different criteria in the limit of infinite chain length: the disappearance of the second viral coefficient, the abrupt change in chain size and the critical point in the phase diagram of the polymer solution. Our results show the value of chi at the Theta point is 0.5 (for the case of equal monomer and solvent volume), which coincides with the value predicted from the F-H theory.

Rui Wang; Zhen-Gang Wang

2014-06-05T23:59:59.000Z

459

Magnetic mirror fusion-fission early history and applicability to other systems  

SciTech Connect (OSTI)

In the mid 1970s to mid 1980s the mirror program was stuck with a concept, the Standard Mirror that was Q {approx} 1 where Q=P{sub fusion}/P{sub injection}. Heroic efforts were put into hybridizing thinking added energy and fuel sales would make a commercial product. At the same time the tokamak was thought to allow ignition and ultrahigh Q values of 20 or even higher. There was an effort to use neutral beams to drive the tokamak just like the mirror machines were driven in which case the Q value plunged to a few, however this was thought to be achievable decades earlier than the high Q versions. Meanwhile current drive and other features of the tokamak have seen the projected Q values come down to the range of 10. Meanwhile the mirror program got Q enhancement into high gear and various tandem mirrors projected Q values up towards 10 and with advanced features over 10 with axi-symmetric magnets (See R. F. Post papers), however the experimental program is all but non-existent. Meanwhile, the gas dynamic trap mirror system which is present day state-of-the-art can with low risk produce Q of {approx}0.1 useful for a low risk, low cost neutron source for materials development useful for the development of materials for all fusion concepts (see Simonen white paper: 'A Physics-Based Strategy to Develop a Mirror Fusion-Fission Hybrid' and D.D. Ryutov, 'Axisymmetric MHD-stable mirror as a neutron source and a driver for a fusion-fission hybrid'). Many early hybrid designs with multi-disciplinary teams were carried out in great detail for the mirror system with its axi-symmetric blanket modules. It is recognized that most of these designs are adaptable to tokamak or inertial fusion geometry. When Q is low (1 to 2) economics gives a large economic penalty for high recirculating power. These early studies covered the three design types: Power production, fuel production and waste burning. All three had their place but power production fell away because every study showed fusion machines that were extensively studied by multidisciplinary teams came up with power costs much higher than for existing fission plants except in very large sizes (3 GWe). There was lots of work on waste burning - Ted Parrish - comes to mind. However, fuel production along with power production became nearly everyone's goals. First, fast-fission blankets were favored but later to enhance safety, fission-suppressed blankets came into vogue. Both fuel producing and waste burning hybrid studies were terminated with the advent of accidents, high interest rates, rising 'green like' movement and cheap natural gas for power production. For waste burning and fast-fission fuel producing designs, the blanket energy multiplication was about 10 and economics was OK relative to recirculating power for Q over 2. For fission-suppressed fuel producers, where the blanket multiplication is under 2, the Q needed was over 5. In the mirror program we came at this problem by trying to find a product for mirror fusion technology. We hoped we had a product and studied and promoted it. There was no market pull and when the mirror program collapsed in the US, so did both hybrid programs for mirrors and tokamaks and IFE by the mid 1980s. Today, the problem of what to do with wastes that were supposed to be accepted by the government appears to be a high value market pull. It remains to be shown if fusion neutrons can be generated at low enough cost so that economics will not be a showstopper. For burning only the minor actinides, the economics will be the most favorable. Burning the Pu as well will lower the number of fission reactors supported by each burner fusion machine and hurt economics of the system. The fuel-producing role of fusion to fuel fission reactors remains an important possible use of fusion especially in the early stages of fusion development. It is not clear that burning fission wastes in a fusion machine is more appropriate than burning these wastes in specially designed fission machines. Fusion can produce U-233 along with over 2.4%U-232 making the material large

Moir, R

2009-08-24T23:59:59.000Z

460

Antibody heterogeneity and serological reactions.  

Science Journals Connector (OSTI)

...According to the experience of most investi- gators, the first antibody to be detected in...reactions observed by numerous other investi- gators, and noted that such reactions could...globulins (35), although several investi- gators had reported antibody activity in serum...

R M Pike

1967-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "fission chain reaction" from the National Library of EnergyBeta (NLEBeta).
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461

A toolbox for simulation-based optimization of supply chains  

Science Journals Connector (OSTI)

In this paper we present a general framework for simulating and optimizing the operational decisions in a supply chain network. We developed a supply chain network library for the simulation software AnyLogic (© XJ Technologies) and a linearized ...

Christian Almeder; Margaretha Preusser

2007-12-01T23:59:59.000Z

462

Distributed simulation for interoperability testing along the supply chain  

Science Journals Connector (OSTI)

The need for interoperability of information systems among supply chain partners has been recognized. A number of standards have been or are being developed to ensure interoperability of applications used along the supply chain. An associated need for ...

Sanjay Jain; Frank Riddick; Andreas Craens; Deogratias Kibira

2007-12-01T23:59:59.000Z

463

SC COLLABORATOR: A SERVICE ORIENTED FRAMEWORK FOR CONSTRUCTION SUPPLY CHAIN  

E-Print Network [OSTI]

, service oriented architecture (SOA) with open source technologies is a desirable computing modelSC COLLABORATOR: A SERVICE ORIENTED FRAMEWORK FOR CONSTRUCTION SUPPLY CHAIN COLLABORATION for construction supply chain collaboration and management, through a prototype service oriented system framework

Stanford University

464

Sustainable Supply Chain Network Design: A Multicriteria Perspective Anna Nagurney  

E-Print Network [OSTI]

Sustainable Supply Chain Network Design: A Multicriteria Perspective Anna Nagurney Department West Hartford, Connecticut 06117 August 2009; revised April 2010 International Journal of Sustainable framework for the design of sustainable supply chain networks. We consider a firm that is engaged

Nagurney, Anna

465

Optimum Algorithms for a Model of Direct Chaining  

E-Print Network [OSTI]

Direct chaining is a popular and efficient class of hashing algorithms. In this paper we study optimum algorithms among direct chaining methods, under the restrictions that the records in the hash table are not moved after ...

Vitter, Jeffrey Scott; Chen, Wen-Chin

1985-05-01T23:59:59.000Z

466

Global Supply Chain Analysis of U.S. Lamb Promotion  

E-Print Network [OSTI]

.................................................................................... 18 Australia Lamb Supply Chain .................................................................................. 19 New Zealand Lamb Supply Chain ........................................................................... 23 The U.S. Sheep... The Australian Wool Industry .................................................................................. 42 The New Zealand Wool Industry ............................................................................. 44 Raw Wool Trade Between Oceania...

Ghosh, Somali

2014-04-13T23:59:59.000Z

467

SKU segmentation strategy for a global retail supply chain  

E-Print Network [OSTI]

The concept of using different supply chain strategies for different products or product families is a fairly simple component of supply chain management. This practice, known as SKU segmentation, is widely used by many ...

Jin, Huiping, M. Eng. Massachusetts Institute of Technology

2014-01-01T23:59:59.000Z

468

Metal-Ion-Mediated Reactions  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Metal-Ion-Mediated Reactions Metal-Ion-Mediated Reactions Metal-Ion-Mediated Reactions Print Monday, 19 December 2011 18:29 While mononuclear, polynuclear, and polymeric metal complexes are most often synthesized by the reaction of a metal precursor and a presynthesized organic ligand, it is also possible to generate the ligand in situ from an easily available organic compound. This approach allows the reactivity of the metal ion to activate a proligand, transforming it through an in situ reaction, sometimes providing coordination compounds with ligands not accessible by conventional organic synthesis. The intense interest in the reactivity of coordinated ligands is mainly due to the necessity of interpreting the mechanisms of homogeneous metal-catalyzed processes, in which a substrate is activated upon its coordination to one or more metal sites. A coordinated oxime group contains three active sites (C, N, O) for reactivity.

469

The development of an assay procedure for long-chain acyl-CoA synthetase  

E-Print Network [OSTI]

~ 8 Assay procedure Other Methods 8 13 RESULTS 14 Use of Labeled CoA for Assaying Long-Chain Acyl-CoA Synthetase 14 Kinetics of Fatty Acid Activation Using CoA and ECoA as Variable Substrate 15 Separation of Acyl-ECoA from ECoA 19 Thin Layer... as micromoles of acyl-CoA formed per hour per mg of protein; S is in units of micro- molar. Reaction conditions are' described in the text 5. Percentage [ C)acyl-ECoA precipitated as a 14 function of the acyl-CoA concentration 18 22 INTRODUCTION Long...

Jones, Harvey Duane

1975-01-01T23:59:59.000Z

470

Ising Chain with a Spin Impurity  

Science Journals Connector (OSTI)

Consider a closed, linear chain of N localized spins (each s=12) with nearest-neighbor Ising interaction. Such a chain, exposed to a uniform external magnetic field, will be called the pure host. Replace a single spin in the pure host by an impurity spin which is also subjected to nearest-neighbor Ising interaction and to the external field. The magnitude of the impurity spin, the magnitude of its magnetic moment, and the magnitude and sign of its interaction with the host are allowed to differ from the corresponding values characterizing the host. For the bulk system (N??, for constant linear density of spins), the thermodynamic properties, such as the impurity magnetization, the (position-dependent) magnetization of the impurity-host system and the impurity-host spin correlation functions, are obtained exactly in terms of conventional, tabulated functions. Numerical results are presented for impurity spins of magnitude S=32,52.

H. Falk

1966-11-04T23:59:59.000Z

471

Method for preparation of single chain antibodies  

DOE Patents [OSTI]

This invention provides a method for identifying cells expressing a target single chain antibody (scFv) directed against a target antigen from a collection of cells that includes cells that do not express the target scFv, comprising the step of combining the collection of cells with an anti-idiotype directed to an antibody specific for the target antigen and detecting interaction, if any, of the anti-idiotype with the cells, wherein the occurrence of an interaction identifies the cell as one which expresses the target scFv. This invention also provides a method for making a single chain antibody (scFv) directed against an antigen, wherein the selection of clones is made based upon interaction of those clones with an appropriate anti-idiotype, and heretofore inaccessible scFv so made. This invention provides the above methods or any combination thereof. Finally, this invention provides various uses of these methods.

Cheung, Nai-Kong V. (New York, NY); Guo, Hong-fen (New York, NY)

2012-04-03T23:59:59.000Z

472

Intelligent supply chain by using prognostic logistics  

Science Journals Connector (OSTI)

The use of technological tools in logistics is intended to increase visibility, capacity and control in the supply chain. Decrease of uncertainties due to asymmetric data has been the constant challenge of management. Misdiagnosis of situations and equipment, inaccurate production planning, shrinkage and counterfeiting are some of the consequences of erroneous information. The idea of prognostic logistics is to use real time information and an intelligent system to diagnose and predict early failures and hazardous situations. The automatic capture of information in prognostic logistics has the intent to reduce human errors. Automatic identification technologies enable the creation of a prognostic logistic network where real time information is used to make accurate forecasting, pushing a proactive supply chain instead of a reactive one.

Adriana M. Lopez De La Cruz; Hans P.M. Veeke; Gabriel Lodewijks

2007-01-01T23:59:59.000Z

473