Prompt-fission Neutron Spectra of 233U, 235U, 239Pu and 240Pu Relative to that of 252Cf

Prompt-fission Neutron Spectra of 233U, 235U, 239Pu and 240Pu Relative to that of 252Cf PDF Author: A. Smith
Publisher:
ISBN:
Category : Californium
Languages : en
Pages : 17

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Prompt-fission Neutron Spectra of 233U, 235U, 239Pu and 240Pu Relative to that of 252Cf

Prompt-fission Neutron Spectra of 233U, 235U, 239Pu and 240Pu Relative to that of 252Cf PDF Author: A. Smith
Publisher:
ISBN:
Category : Californium
Languages : en
Pages : 17

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Book Description


Prompt-fission-neutron Spectra of 233U, 235U, 239Pu and 24°Pu Relative to that of 252Cf. [550 and 850 KeV].

Prompt-fission-neutron Spectra of 233U, 235U, 239Pu and 24°Pu Relative to that of 252Cf. [550 and 850 KeV]. PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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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.

Prompt Neutron Fission Spectrum Mean Energies for the Fissile Nuclides and 252Cf

Prompt Neutron Fission Spectrum Mean Energies for the Fissile Nuclides and 252Cf PDF Author:
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ISBN:
Category :
Languages : en
Pages :

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Book Description
The international standard for a neutron spectrum is that produced from the spontaneous fission of 252Cf, while the thermal neutron induced fission neutron spectra for the four fissile nuclides, 233U, 235U, 239Pu, and 241Pu are of interest from the standpoint of nuclear reactors. The average neutron energies of these spectra are tabulated. The individual measurements are recorded with the neutron energy range measured, the method of detection as well as the average neutron energy for each author. Also tabulated are the measurements of the ratio of mean energies for pairs of fission neutron spectra. 75 refs., 9 tabs. (LEW).

Nuclear Data and Measurements Series

Nuclear Data and Measurements Series PDF Author:
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ISBN:
Category :
Languages : en
Pages :

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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.

Mean Fission Neutron Spectrum Energies for 252Cf and Fissile Nuclides, 233U, 235U, 239Pu and 241Pu

Mean Fission Neutron Spectrum Energies for 252Cf and Fissile Nuclides, 233U, 235U, 239Pu and 241Pu PDF Author:
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ISBN:
Category :
Languages : en
Pages :

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Book Description
The international standard for a neutron spectrum is that produced from the spontaneous fission of 252Cf, while the thermal neutron induced fission neutron spectra for the four fissile nuclides, 233U, 235U, 239Pu and 241Pu, are of interest from the standpoint of nuclear reactors. There have been many data sets produced in recent years which deal with the shape of these spectra, particularly at both the low energy and the high energy portions of the curve. However, our interest here is in the average neutron energies of these spectra. We have tabulated all measurements for the five nuclides of interest. The individual measurements are recorded with the neutron energy range measured, the method of detection as well as the average neutron energy for each author. Fortunately, the measurements have been performed with a number of techniques, which allows one to estimate the systematic error from the spread in the results for the different techniques. An attempt has been made to renormalize results when the neutron spectrum used for normalization purposes has been given. In addition to the tables of mean energy measurements, we have also tabulated the measurements of the ratio of mean energies for pairs of fission neutron spectra. The following items were considered, where possible, in the analysis of the mean energies of the neutron spectra: the energy scale of the measurement, the determination of the detector efficiency, the sample size and the sample thickness and the scattering corrections made. The recommended mean energies for the spectra considered are shown. The uncertainty listed attempts to estimate the systematic error as well as merely the precision in each of the experiments. The recommended values for /sup 233,235/U, /sup 239,241/Pu, and 252Cf are 2.02 +- 0.03 MeV, 1.98 +- 0.03 MeV, 2.06 +- 0.04 MeV, 2.05 +- 0.05 MeV, and 2.14 +- 0.03 MeV, respectively. 73 refs.

Mean Fission Neutron Spectrum Energies for 252Cf and Fissile Nuclides 233U, 235U, 239Pu and 241Pu

Mean Fission Neutron Spectrum Energies for 252Cf and Fissile Nuclides 233U, 235U, 239Pu and 241Pu PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 7

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Nuclear Fission

Nuclear Fission PDF Author: Patrick Talou
Publisher: Springer Nature
ISBN: 3031145453
Category : Science
Languages : en
Pages : 487

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Book Description
This book provides advanced students and postdocs, as well as current practitioners of any field of nuclear physics involving fission an understanding of the nuclear fission process. Key topics covered are: fission cross sections, fission fragment yields, neutron and gamma emission from fission and key nuclear technologies and applications where fission plays an important role. It addresses both fundamental aspects of the fission process and fission-based technologies including combining quantitative and microscopic modeling.

The Need for Precise and Well-documented Experimental Data on Prompt Fission Neutron Spectra from Neutron-induced Fission of 239Pu

The Need for Precise and Well-documented Experimental Data on Prompt Fission Neutron Spectra from Neutron-induced Fission of 239Pu PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 30

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Book Description
The spectrum of neutrons emitted promptly after 239Pu(n, f)--a so-called prompt fission neutron spectrum (PFNS)--is a quantity of high interest, for instance, for reactor physics and global security. However, there are only few experimental data sets available that are suitable for evaluations. In addition, some of those data sets differ by more than their 1-[sigma] uncertainty boundaries. We present the results of MCNP studies indicating that these differences are partly caused by underestimated multiple scattering contributions, over-corrected background, and inconsistent deconvolution methods. A detailed uncertainty quantification for suitable experimental data was undertaken including these effects, and test-evaluations were performed with the improved uncertainty information. The test-evaluations illustrate that the inadequately estimated effects and detailed uncertainty quantification have an impact on the evaluated PFNS and associated uncertainties as well as the neutron multiplicity of selected critical assemblies. A summary of data and documentation needs to improve the quality of the experimental database is provided based on the results of simulations and test-evaluations. Furthermore, given the possibly substantial distortion of the PFNS by multiple scattering and background effects, special care should be taken to reduce these effects in future measurements, e.g., by measuring the 239Pu PFNS as a ratio to either the 235U or 252Cf PFNS.

Evaluation of the Thermal Constants of 233U, 235U, 239Pu and 241Pu, and the Fission Neutron Yield of 252Cf

Evaluation of the Thermal Constants of 233U, 235U, 239Pu and 241Pu, and the Fission Neutron Yield of 252Cf PDF Author: E. J. Axton
Publisher:
ISBN:
Category : Californium
Languages : en
Pages : 38

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Recent Improvements in the Calculation of Prompt Fission Neutron Spectra

Recent Improvements in the Calculation of Prompt Fission Neutron Spectra PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
Three tropics have been considered in the refinement and improvement of our original calculations of prompt fission neutron spectra. These are an improved calculation of the prompt fission neutron spectrum N(E) from the spontaneous fission of 252Cf, a complete calculation of the prompt fission neutron spectrum matrix N(E, E/sub n/) from the neutron-induced fission of 235U, at incident neutron energies ranging from 0 to 15 MeV, and an assessment of the scission neutron component of the prompt fission neutron spectrum. Preliminary results will be presented and compared with experimental measurements and an evaluation. A suggestion has been made for new integral cross-section measurements.