Evaluation and application of delayed neutron precursor data /
| Main Author: | |
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1988.
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| Subjects: | |
| Online Access: | ProQuest, Abstract Link to OAKTrust copy |
| 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 compiled which contains fission yields and branchings, delayed neutron emission probabilities and spectra for each of these 271 precursor nuclides. The emphasis of the present work has been in improving the spectral data. Experimental spectra from laboratories in the United States, Germany, and Sweden have been incorporated in this evaluation. The experimental spectra have been augmented with model calculations such that the spectra included in the final library extend over the full theoretical energy range for delayed neutron emission. Models were also used to predict spectra for nuclides with no measured data. The data compiled in the precursor library have been used to calculate the aggregate behavior of delayed neutrons for the 43 fissioning systems 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 235U 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 m 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. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Nuclear Engineering." |
| Physical Description: | xii, 282 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |