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Title: Improved Cumulative Fission Yield Measurements with Fission Spectrum Neutrons on 238U

Abstract

Two isotopically-characterized targets of high-purity (99.961±0.002%) 238U metal and a neutron dosimetry package were exposed to a pulsed neutron irradiation using the Godiva IV critical assembly at the National Criticality Experiments Research Center to measure the integral fission product yields produced in a Watt fission neutron-energy spectrum. Following irradiation, the fissioned targets were counted with two broad energy germanium detectors. Estimates of the total fissions for each target were made using measurements of well-known fission products. The total number of fissions in each target were then used to measure the fission yields of 33 fission products, 18 of which are published as new measurements. Twelve of the 18 isotopes were in agreement with ENDF/B- VIII.0 using the zeta test and treating ENDF/B-VIII.0 as the true mean: 84mBr, 93Y, 94Y, 104Tc, 134I, 135I, 138Xe, 141Ba, 142Ba, 142La, 146Ce, and 149Nd. The ENDF/B-VIII.0 fission yield for 139Ba was only slightly outside of 1-s relative to the uncertainty measured in this work. Uncertainties for 5 fission product yields were markedly improved over those reported in ENDF/B-VIII.0: 128Sn, 129Sb, 130gSb, 131mTe, and 133I. The fission yields measured for 128Sn, 131mTe, and 133I were in good agreement with the ENDF/B-VIII.0 predicted fission yields. However, fissionmore » yields measurements of the isotopes 129Sb, and 130gSb deviated from the ENDF/B-VIII.0 value. Both of these isotopes reside near the doubly magic nuclear shell closures of 50 protons and 82 neutrons. These fission yields may be suppressed because of the odd-odd nuclear structure of 130gSb and the odd-even structure of 129Sb and isomer splitting. Comparisons to other recent work and a brief review with citations are included to support this conclusion.« less

Authors:
 [1]; ORCiD logo [1]; ORCiD logo [1];  [2];  [2];  [1];  [3];  [3];  [3];  [4];  [1];  [2]; ORCiD logo [1];  [2];  [5]
  1. BATTELLE (PACIFIC NW LAB)
  2. Lawrence Livermore National Laboratory
  3. Los Alamos National Laboratory
  4. Lawrence Livermore National Lab
  5. Oregon State University
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1599171
Report Number(s):
PNNL-SA-148863
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Nuclear Data Sheets
Additional Journal Information:
Journal Volume: 163
Country of Publication:
United States
Language:
English
Subject:
Fission Yields

Citation Formats

Pierson, Bruce D., Greenwood, Lawrence R., Stave, Sean C., Burke, J T., Padgett, Stephen W., Prinke, Amanda M., Goda, Joetta A., Bounds, John A., Hayes, David K., Tamashiro, Aaron, Wittman, Richard S., Slavik, Gary W., Dion, Michael P., Burch, Jennifer G., and Palmer, Todd. Improved Cumulative Fission Yield Measurements with Fission Spectrum Neutrons on 238U. United States: N. p., 2020. Web. doi:10.1016/j.nds.2019.12.006.
Pierson, Bruce D., Greenwood, Lawrence R., Stave, Sean C., Burke, J T., Padgett, Stephen W., Prinke, Amanda M., Goda, Joetta A., Bounds, John A., Hayes, David K., Tamashiro, Aaron, Wittman, Richard S., Slavik, Gary W., Dion, Michael P., Burch, Jennifer G., & Palmer, Todd. Improved Cumulative Fission Yield Measurements with Fission Spectrum Neutrons on 238U. United States. doi:10.1016/j.nds.2019.12.006.
Pierson, Bruce D., Greenwood, Lawrence R., Stave, Sean C., Burke, J T., Padgett, Stephen W., Prinke, Amanda M., Goda, Joetta A., Bounds, John A., Hayes, David K., Tamashiro, Aaron, Wittman, Richard S., Slavik, Gary W., Dion, Michael P., Burch, Jennifer G., and Palmer, Todd. Thu . "Improved Cumulative Fission Yield Measurements with Fission Spectrum Neutrons on 238U". United States. doi:10.1016/j.nds.2019.12.006.
@article{osti_1599171,
title = {Improved Cumulative Fission Yield Measurements with Fission Spectrum Neutrons on 238U},
author = {Pierson, Bruce D. and Greenwood, Lawrence R. and Stave, Sean C. and Burke, J T. and Padgett, Stephen W. and Prinke, Amanda M. and Goda, Joetta A. and Bounds, John A. and Hayes, David K. and Tamashiro, Aaron and Wittman, Richard S. and Slavik, Gary W. and Dion, Michael P. and Burch, Jennifer G. and Palmer, Todd},
abstractNote = {Two isotopically-characterized targets of high-purity (99.961±0.002%) 238U metal and a neutron dosimetry package were exposed to a pulsed neutron irradiation using the Godiva IV critical assembly at the National Criticality Experiments Research Center to measure the integral fission product yields produced in a Watt fission neutron-energy spectrum. Following irradiation, the fissioned targets were counted with two broad energy germanium detectors. Estimates of the total fissions for each target were made using measurements of well-known fission products. The total number of fissions in each target were then used to measure the fission yields of 33 fission products, 18 of which are published as new measurements. Twelve of the 18 isotopes were in agreement with ENDF/B- VIII.0 using the zeta test and treating ENDF/B-VIII.0 as the true mean: 84mBr, 93Y, 94Y, 104Tc, 134I, 135I, 138Xe, 141Ba, 142Ba, 142La, 146Ce, and 149Nd. The ENDF/B-VIII.0 fission yield for 139Ba was only slightly outside of 1-s relative to the uncertainty measured in this work. Uncertainties for 5 fission product yields were markedly improved over those reported in ENDF/B-VIII.0: 128Sn, 129Sb, 130gSb, 131mTe, and 133I. The fission yields measured for 128Sn, 131mTe, and 133I were in good agreement with the ENDF/B-VIII.0 predicted fission yields. However, fission yields measurements of the isotopes 129Sb, and 130gSb deviated from the ENDF/B-VIII.0 value. Both of these isotopes reside near the doubly magic nuclear shell closures of 50 protons and 82 neutrons. These fission yields may be suppressed because of the odd-odd nuclear structure of 130gSb and the odd-even structure of 129Sb and isomer splitting. Comparisons to other recent work and a brief review with citations are included to support this conclusion.},
doi = {10.1016/j.nds.2019.12.006},
journal = {Nuclear Data Sheets},
number = ,
volume = 163,
place = {United States},
year = {2020},
month = {1}
}