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Title: Thermal scattering law of C 2 H 4 n : Integrating experimental data with DFT calculations

Abstract

Improvements in determination of the thermal scattering law of moderator materials (measuring, calculating and validating) are important for accurate prediction of neutron thermalization in nuclear systems. In this paper a methodology for producing thermal scattering libraries from the experimental data for polyethylene C 2 H 4 n is discussed. Double differential scattering cross section (DDSCS) experiments were performed at the Spallation Neutron Source of Oak Ridge National Laboratory (SNS ORNL). New scattering kernel evaluations, based on phonon spectrum for C 2 H 4 n , are created using the NJOY2016 code. Two different methods were used: direct and indirect geometry neutron scattering at ARCS and SEQUOIA, and VISION instruments, respectively, where the phonon spectrum was derived from the dynamical structure factor S(Q, ω ) obtained from the measured DDSCS. In order to compare and validate the newly created library, the experimental setup was simulated using MCNP6.1. Compared with the current ENDF/B-VII.1, the resulting RPI C 2 H 4 n libraries improved both double differential scattering and total scattering cross sections. A set of criticality benchmarks containing C 2 H 4 n from HEU-MET-THERM resulted in an overall improved calculation of K eff , although the libraries should be tested against benchmarks more sensitive to C 2 H 4 n . The DFT + oClimax method is used and is shown to be most comprehensive method for analysis of moderator materials. Finally, the importance of DFT + oClimax method lies in the fact that it can be validated against all data measured at VISION, ARCS and SEQUOIA, and experimental total scattering cross section measurements.

Authors:
 [1];  [1];  [2];  [2];  [2];  [2];  [2];  [3];  [1];  [1]
  1. Rensselaer Polytechnic Inst., Troy, NY (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Neutron Scattering Division
  3. Radioprotection and Nuclear Safety Inst. (IRSN), Paris (France)
Publication Date:
Research Org.:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
OSTI Identifier:
1460187
Alternate Identifier(s):
OSTI ID: 1543158
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Accepted Manuscript
Journal Name:
Annals of Nuclear Energy (Oxford)
Additional Journal Information:
Journal Name: Annals of Nuclear Energy (Oxford); Journal Volume: 120; Journal ID: ISSN 0306-4549
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; phonon spectrum; ENDF; neutron scattering; double differential scattering cross section; GDOS; polyethylene; criticality safety; density function theory

Citation Formats

Ramic, Kemal, Wendorff, Carl, Cheng, Yongqiang, Kolesnikov, Alexander I., Abernathy, Doug L., Daemen, Luke, Arbanas, Goran, Leal, Luiz, Danon, Yaron, and Liu, Li Emily. Thermal scattering law of C2H4n : Integrating experimental data with DFT calculations. United States: N. p., 2018. Web. doi:10.1016/j.anucene.2018.06.029.
Ramic, Kemal, Wendorff, Carl, Cheng, Yongqiang, Kolesnikov, Alexander I., Abernathy, Doug L., Daemen, Luke, Arbanas, Goran, Leal, Luiz, Danon, Yaron, & Liu, Li Emily. Thermal scattering law of C2H4n : Integrating experimental data with DFT calculations. United States. https://doi.org/10.1016/j.anucene.2018.06.029
Ramic, Kemal, Wendorff, Carl, Cheng, Yongqiang, Kolesnikov, Alexander I., Abernathy, Doug L., Daemen, Luke, Arbanas, Goran, Leal, Luiz, Danon, Yaron, and Liu, Li Emily. Sat . "Thermal scattering law of C2H4n : Integrating experimental data with DFT calculations". United States. https://doi.org/10.1016/j.anucene.2018.06.029. https://www.osti.gov/servlets/purl/1460187.
@article{osti_1460187,
title = {Thermal scattering law of C2H4n : Integrating experimental data with DFT calculations},
author = {Ramic, Kemal and Wendorff, Carl and Cheng, Yongqiang and Kolesnikov, Alexander I. and Abernathy, Doug L. and Daemen, Luke and Arbanas, Goran and Leal, Luiz and Danon, Yaron and Liu, Li Emily},
abstractNote = {Improvements in determination of the thermal scattering law of moderator materials (measuring, calculating and validating) are important for accurate prediction of neutron thermalization in nuclear systems. In this paper a methodology for producing thermal scattering libraries from the experimental data for polyethylene C2H4n is discussed. Double differential scattering cross section (DDSCS) experiments were performed at the Spallation Neutron Source of Oak Ridge National Laboratory (SNS ORNL). New scattering kernel evaluations, based on phonon spectrum for C2H4n, are created using the NJOY2016 code. Two different methods were used: direct and indirect geometry neutron scattering at ARCS and SEQUOIA, and VISION instruments, respectively, where the phonon spectrum was derived from the dynamical structure factor S(Q,ω) obtained from the measured DDSCS. In order to compare and validate the newly created library, the experimental setup was simulated using MCNP6.1. Compared with the current ENDF/B-VII.1, the resulting RPI C2H4n libraries improved both double differential scattering and total scattering cross sections. A set of criticality benchmarks containing C2H4n from HEU-MET-THERM resulted in an overall improved calculation of Keff, although the libraries should be tested against benchmarks more sensitive to C2H4n. The DFT + oClimax method is used and is shown to be most comprehensive method for analysis of moderator materials. Finally, the importance of DFT + oClimax method lies in the fact that it can be validated against all data measured at VISION, ARCS and SEQUOIA, and experimental total scattering cross section measurements.},
doi = {10.1016/j.anucene.2018.06.029},
journal = {Annals of Nuclear Energy (Oxford)},
number = ,
volume = 120,
place = {United States},
year = {Sat Jun 30 00:00:00 EDT 2018},
month = {Sat Jun 30 00:00:00 EDT 2018}
}

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Cited by: 9 works
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