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Title: Evaluation and application of delayed-neutron precursor data

Abstract

Up to 1300 nuclides are yielded in fission. Of these, 271 have been identified as precursors for delayed neutron emission. An extensive reference library of delayed neutron data has been complied which contains fission yields and branchings, delayed neutron emission probabilities and spectra for each of these 271 precursor nuclides. The data complied in the precursor library have been used to calculate the aggregate behavior of delayed neutrons for the 43 fissioning system having evaluated fission yields. Delayed neutron activities predicted using the explicit precursor data have also been approximated by three, six, nine, and twelve time-groups using least squares techniques. The fitted six group data, being the more conventional representation, were also used to predict a consistent set of six-group spectra. Comparisons with the University of Lowell's recently published measurements of {sup 235}U delay interval spectra were also made. Beta-effective calculations for a simple Godiva system were performed and were compared to the experimental value. The point reactor kinetics equations were modified to accommodate the data in the precursor library. Both the explicit data and the group data were used to calculate the kinetic response of a reactor to step changes in reactivity. The precursor data and the six-groupmore » data are intended for inclusion in the next version of the Evaluated Nuclear Data Files, ENDF/B-VI.« less

Authors:
Publication Date:
Research Org.:
Texas A and M Univ., College Station, TX (USA)
OSTI Identifier:
6547508
Resource Type:
Miscellaneous
Resource Relation:
Other Information: Thesis (Ph. D.)
Country of Publication:
United States
Language:
English
Subject:
22 GENERAL STUDIES OF NUCLEAR REACTORS; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; NUCLEAR DATA COLLECTIONS; REACTOR KINETICS; COMPARATIVE EVALUATIONS; COMPILED DATA; DELAYED NEUTRONS; EVALUATION; FISSION YIELD; MODIFICATIONS; REACTIVITY; REACTOR KINETICS EQUATIONS; USES; BARYONS; DATA; ELEMENTARY PARTICLES; EQUATIONS; FERMIONS; FISSION NEUTRONS; HADRONS; INFORMATION; KINETICS; NEUTRONS; NUCLEAR REACTION YIELD; NUCLEONS; NUMERICAL DATA; YIELDS; 220100* - Nuclear Reactor Technology- Theory & Calculation; 990300 - Information Handling

Citation Formats

Brady, M C. Evaluation and application of delayed-neutron precursor data. United States: N. p., 1988. Web.
Brady, M C. Evaluation and application of delayed-neutron precursor data. United States.
Brady, M C. 1988. "Evaluation and application of delayed-neutron precursor data". United States.
@article{osti_6547508,
title = {Evaluation and application of delayed-neutron precursor data},
author = {Brady, M C},
abstractNote = {Up to 1300 nuclides are yielded in fission. Of these, 271 have been identified as precursors for delayed neutron emission. An extensive reference library of delayed neutron data has been complied which contains fission yields and branchings, delayed neutron emission probabilities and spectra for each of these 271 precursor nuclides. The data complied in the precursor library have been used to calculate the aggregate behavior of delayed neutrons for the 43 fissioning system having evaluated fission yields. Delayed neutron activities predicted using the explicit precursor data have also been approximated by three, six, nine, and twelve time-groups using least squares techniques. The fitted six group data, being the more conventional representation, were also used to predict a consistent set of six-group spectra. Comparisons with the University of Lowell's recently published measurements of {sup 235}U delay interval spectra were also made. Beta-effective calculations for a simple Godiva system were performed and were compared to the experimental value. The point reactor kinetics equations were modified to accommodate the data in the precursor library. Both the explicit data and the group data were used to calculate the kinetic response of a reactor to step changes in reactivity. The precursor data and the six-group data are intended for inclusion in the next version of the Evaluated Nuclear Data Files, ENDF/B-VI.},
doi = {},
url = {https://www.osti.gov/biblio/6547508}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1988},
month = {1}
}

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