Abstract
With the advancements in technology (both experimental and computational) the determination of the“true” experimental phonon spectrum became more accessible. In this work a methodology for producing thermal scattering libraries from the experimental data (namely the DFT + oClimax method) for lucite (C5O2H8)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 the phonon spectrum for (C5O2H8)n,were created using oClimax and NJOY2016 codes. In order to compare and asses the performance of the newly created library, the experimental setup was simulated using MCNP6.1. Compared to the current ENDF/B-VIII.0, the resulting RPI (C5O2H8)n library improved the calculation of both double differential scattering and total scattering cross sections. A set of criticality benchmarks containing (C5O2H8)n from HEU-MET-THERM resulted in an overall improved calculation of Keff. The DFT + oClimax method is shown to be the most comprehensive method for analysis of moderator materials, due to the fact that it can be verified against all data measured at VISION, ARCS and SEQUOIA neutron spectrometers at SNS ORNL, and experimental total scattering cross section measurements. This method also provides a new technique for calculating any phonon spectrum-related quantities such as scattering law kernel, specific heat capacity, thermal conductivity, etc. for any solid state material.
Original language | English |
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Pages (from-to) | 425-430 |
Number of pages | 6 |
Journal | Annals of Nuclear Energy |
Volume | 133 |
DOIs | |
State | Published - Nov 2019 |
Funding
This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy. The research at Oak Ridge National Laboratory’s Spallation Neutron Source was sponsored by the U.S. Department of Energy and by the Scientific User Facilities Division, Office of Basic Energy Sciences, the U.S. Department of Energy. This research was supported by the Nuclear Criticality Safety Program in the U.S. Department of Energy
Keywords
- ARCS spectrometer
- Criticality safety
- Density function theory
- Double differential scattering cross section
- ENDF
- GDOS
- Lucite
- Neutron scattering
- Phonon spectrum
- Polyethylene
- Specific heat capacity
- Thermal conductivity
- VISION spectrometer
- oClimax