Download or read book Evaluating the 239Pu Prompt Fission Neutron Spectrum Induced by Thermal to 30 MeV Neutrons written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a new evaluation of the 239Pu prompt fission neutron spectrum (PFNS) induced by thermal to 30 MeV neutrons. Compared to the ENDF/B-VII. 1 evaluation, this one includes recently published experimental data as well as an improved and extended model description to predict PFNS. For instance, the pre-equilibrium neutron emission component to the PFNS is considered and the incident energy dependence of model parameters is parametrized more realistically. Experimental and model parameter uncertainties and covariances are estimated in detail. Also, evaluated covariances are provided between all PFNS at different incident neutron energies. In conclusion, selected evaluation results and first benchmark calculations using this evaluation are briefly discussed.
Download or read book Evaluation of the 239Pu Prompt Fission Neutron Spectrum Induced by Neutrons of 500 KeV and Associated Covariances written by and published by . This book was released on 2015 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present evaluations of the prompt fission neutron spectrum (PFNS) of 239Pu induced by 500 keV neutrons, and associated covariances. In a previous evaluation by Talou et al. 2010, surprisingly low evaluated uncertainties were obtained, partly due to simplifying assumptions in the quantification of uncertainties from experiment and model. Therefore, special emphasis is placed here on a thorough uncertainty quantification of experimental data and of the Los Alamos model predicted values entering the evaluation. In addition, the Los Alamos model was extended and an evaluation technique was employed that takes into account the qualitative differences between normalized model predicted values and experimental shape data. These improvements lead to changes in the evaluated PFNS and overall larger evaluated uncertainties than in the previous work. However, these evaluated uncertainties are still smaller than those obtained in a statistical analysis using experimental information only, due to strong model correlations. Hence, suggestions to estimate model defect uncertainties are presented, which lead to more reasonable evaluated uncertainties. The calculated keff of selected criticality benchmarks obtained with these new evaluations agree with each other within their uncertainties despite the different approaches to estimate model defect uncertainties. The keff one standard deviations overlap with some of those obtained using ENDF/B-VII. 1, albeit their mean values are further away from unity. Spectral indexes for the Jezebel critical assembly calculated with the newly evaluated PFNS agree with the experimental data for selected (n, [gamma]) and (n, f) reactions, and show improvements for high-energy threshold (n,2n) reactions compared to ENDF/B-VII. 1.
Download or read book Prompt fission neutron Spectra of 233U 235U 239Pu and 24 Pu Relative to that of 252Cf 550 and 850 KeV written by and published by . This book was released on 1979 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The prompt-neutron-induced-fission spectra of 233U, 235U, 239Pu, and 24°Pu are measured relative to the prompt-spontaneous-fission-neutron spectrum of 252Cf. The fission of 233U, 235U, and 239Pu is induced by approx. = 550-keV neutrons, and that of 24°Pu, by approx. = 850-keV neutrons. The emitted fission neutrons are observed over the energy range less than or equal to 0.5 to 10.0 MeV by use of time-of-flight techniques. Analysis of the measured values indicates that the average-fission-neutron energies are -123 +- 30 (233U), -157 +- 24 (235U), -76 +- 29 (239Pu), and -46 +- 29 (24°Pu) keV relative to the energy for 252Cf. The experimental results are compared with those of ENDF/B-V, and a simple behavior of average-prompt-fission-neutron energies is suggested.
Download or read book Introducing Nuclear Data Evaluations of Prompt Fission Neutron Spectra written by and published by . This book was released on 2015 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nuclear data evaluations provide recommended data sets for nuclear data applications such as reactor physics, stockpile stewardship or nuclear medicine. The evaluated data are often based on information from multiple experimental data sets and nuclear theory using statistical methods. Therefore, they are collaborative efforts of evaluators, theoreticians, experimentalists, benchmark experts, statisticians and application area scientists. In this talk, an introductions is given to the field of nuclear data evaluation at the specific example of a recent evaluation of the outgoing neutron energy spectrum emitted promptly after fission from 239Pu and induced by neutrons from thermal to 30 MeV.
Download or read book Nuclear Data and Measurements Series written by and published by . This book was released on 1986 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The prompt-fission-neutron spectrum resulting from 239Pu fission induced by 0.55 MeV incident neutrons is measured from 1.0 to 10.0 MeV relative to that of 235U fission induced by the same incident-energy neutrons. The measurements employ the time-of-flight technique. Energy-dependent ratios of the two spectra are deduced from the measured values over the energy range 1.0 to 10.0 MeV. The experimentally-derived ratio results are compared with those calculated from ENDF/B-V, revision-2, and with results of recent microscopic measurements. Using the ENDF/B-V 235U Watt parameters for the 235U spectrum, the experimental measurements imply a ratio of average fission-spectrum energies of 239Pu/235U = 1.045 +- 0.003, compared to the value 1.046 calculated from ENDF/B-V, revision 2. 12 refs., 2 figs., 2 tabs.
Download or read book Evaluation and Uncertainty Quantification of the Prompt Fission Neutron Spectrum of 239Pu written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Event by event Evaluation of the Prompt Fission Neutron Spectrum from 239Pu n F written by and published by . This book was released on 2011 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1976 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ERDA Energy Research Abstracts written by and published by . This book was released on 1985 with total page 676 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Research Abstracts written by and published by . This book was released on 1986 with total page 876 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Catalog of National Bureau of Standards Publications 1966 1976 written by United States. National Bureau of Standards. Technical Information and Publications Division and published by . This book was released on 1978 with total page 854 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Catalog of National Bureau of Standards Publications 1966 1976 pt 1 2 Key word index written by United States. National Bureau of Standards and published by . This book was released on 1978 with total page 844 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Catalog of National Bureau of Standards Publications 1966 1976 written by United States. National Bureau of Standards and published by . This book was released on 1978 with total page 844 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Research Abstracts written by and published by . This book was released on 1983 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Publications written by United States. National Bureau of Standards and published by . This book was released on 1976 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Catalog of National Bureau of Standards Publications 1966 1976 pt 1 Citations and abstracts v 2 pt 1 Key word index A through L v 2 pt 2 Key word index M through Z written by United States. National Bureau of Standards. Technical Information and Publications Division and published by . This book was released on 1978 with total page 804 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Publications of the National Bureau of Standards Catalog written by United States. National Bureau of Standards and published by . This book was released on 1978 with total page 804 pages. Available in PDF, EPUB and Kindle. Book excerpt:
