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Title: Improved Cumulative Fission Yield Measurements with Fission Spectrum Neutrons on 235U

Abstract

Two well-characterized targets of high-purity (99.84+/-0.03\%) 235U-oxide and a neutron dosimetry package were exposed to a pulsed neutron irradiation using the Godiva critical assembly at the National Criticality Experiments Research Center. Following irradiation, the fissioned targets were counted with a broad-energy germanium detector. Estimates of the total fissions for each target were made using measurements of well known fission products. The total fission values were then used to measure the fission yields of 21 fission products. Mean values of seventeen of the measured fission products fell within the 95\% confidence level of the Evaluated Nuclear Data Files VII.1/b (ENDF/B-VII.1) using the larger of the two uncertainties: 84gBr, 89Rb, 91Sr, 93Y, 97Zr, 101Mo, 105Ru, 128Sn, 129Sb, 130gSb, 131Sb, 131mTe, 133I, 135I, 141Ba, 142Ba, and 142La. Seven isotopes were measured to better precision than is listed in the ENDF/B-VII.1 database: 89Rb, 93Y, 128Sn, 129Sb, 130gSb, 131mTe, and 133I. Four of the measured isotopes were found to be statistically different from the ENDF/B-VII.1 database: 94Y, 134Te, 134I, and 138Xe. Two of the isotopic analyses conducted in this paper fit the parent and daughter data simultaneously. The parent-daughter pairs measured in this way were the 134Te/I and 142Ba/La pairs. The fission yield results obtainedmore » in this way are unique, especially for 134I, because the parent and daughter half-lives are so close. Given the limited number of direct measurements of the 134Te/I pair from fast neutron induced fission and the seemingly high estimate for 134Te from previous work, it is possible that the current published value is more accurate; however, additional measurements of this pair are needed to validate this assertion.« less

Authors:
; ; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1501612
Report Number(s):
PNNL-SA-132098
Journal ID: ISSN 0090-3752
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Nuclear Data Sheets
Additional Journal Information:
Journal Volume: 155; Journal Issue: C; Journal ID: ISSN 0090-3752
Publisher:
Elsevier
Country of Publication:
United States
Language:
English

Citation Formats

Pierson, B. D., Prinke, A. M., Greenwood, L. R., Stave, S. C., Wittman, R. S., Burch, J. G., Burke, J. T., Padgett, S. W., Ressler, J. J., Slavik, G., Tamashiro, A., Tonchev, A., and Younes, W. Improved Cumulative Fission Yield Measurements with Fission Spectrum Neutrons on 235U. United States: N. p., 2019. Web. doi:10.1016/j.nds.2019.01.005.
Pierson, B. D., Prinke, A. M., Greenwood, L. R., Stave, S. C., Wittman, R. S., Burch, J. G., Burke, J. T., Padgett, S. W., Ressler, J. J., Slavik, G., Tamashiro, A., Tonchev, A., & Younes, W. Improved Cumulative Fission Yield Measurements with Fission Spectrum Neutrons on 235U. United States. doi:10.1016/j.nds.2019.01.005.
Pierson, B. D., Prinke, A. M., Greenwood, L. R., Stave, S. C., Wittman, R. S., Burch, J. G., Burke, J. T., Padgett, S. W., Ressler, J. J., Slavik, G., Tamashiro, A., Tonchev, A., and Younes, W. Tue . "Improved Cumulative Fission Yield Measurements with Fission Spectrum Neutrons on 235U". United States. doi:10.1016/j.nds.2019.01.005.
@article{osti_1501612,
title = {Improved Cumulative Fission Yield Measurements with Fission Spectrum Neutrons on 235U},
author = {Pierson, B. D. and Prinke, A. M. and Greenwood, L. R. and Stave, S. C. and Wittman, R. S. and Burch, J. G. and Burke, J. T. and Padgett, S. W. and Ressler, J. J. and Slavik, G. and Tamashiro, A. and Tonchev, A. and Younes, W.},
abstractNote = {Two well-characterized targets of high-purity (99.84+/-0.03\%) 235U-oxide and a neutron dosimetry package were exposed to a pulsed neutron irradiation using the Godiva critical assembly at the National Criticality Experiments Research Center. Following irradiation, the fissioned targets were counted with a broad-energy germanium detector. Estimates of the total fissions for each target were made using measurements of well known fission products. The total fission values were then used to measure the fission yields of 21 fission products. Mean values of seventeen of the measured fission products fell within the 95\% confidence level of the Evaluated Nuclear Data Files VII.1/b (ENDF/B-VII.1) using the larger of the two uncertainties: 84gBr, 89Rb, 91Sr, 93Y, 97Zr, 101Mo, 105Ru, 128Sn, 129Sb, 130gSb, 131Sb, 131mTe, 133I, 135I, 141Ba, 142Ba, and 142La. Seven isotopes were measured to better precision than is listed in the ENDF/B-VII.1 database: 89Rb, 93Y, 128Sn, 129Sb, 130gSb, 131mTe, and 133I. Four of the measured isotopes were found to be statistically different from the ENDF/B-VII.1 database: 94Y, 134Te, 134I, and 138Xe. Two of the isotopic analyses conducted in this paper fit the parent and daughter data simultaneously. The parent-daughter pairs measured in this way were the 134Te/I and 142Ba/La pairs. The fission yield results obtained in this way are unique, especially for 134I, because the parent and daughter half-lives are so close. Given the limited number of direct measurements of the 134Te/I pair from fast neutron induced fission and the seemingly high estimate for 134Te from previous work, it is possible that the current published value is more accurate; however, additional measurements of this pair are needed to validate this assertion.},
doi = {10.1016/j.nds.2019.01.005},
journal = {Nuclear Data Sheets},
issn = {0090-3752},
number = C,
volume = 155,
place = {United States},
year = {2019},
month = {1}
}