Abstract
In the conventional method to generate thermal scattering cross section of moderator materials, only one of the coherent elastic scattering and incoherent elastic scattering is considered in neutronics calculations. For the inelastic scattering, fixed incident energy grid is used in the nuclear data processing codes. The multipoint linearization method is used to refine the incident energy grid for inelastic scattering. We select ZrHx (zirconium hydride) as an example to analyze the effects of the above described treatments on the reactivity of several critical benchmarks. The numerical results show that the incident energy grid has an obvious effect on the effective multiplication factor (keff) of the analyzed reactors; simultaneously considering the coherent and incoherent elastic scattering also affects keff by tens of pcm.
Highlights
In the neutronics analysis of nuclear reactors, accurate prediction of the thermal neutron distribution has an important effect on behaviors of the reactors
Because the thermal scattering law (TSL) data for coherent elastic scattering are not provided for ZrHx in the Evaluated Nuclear Data Files (ENDF), in this work, we calculated these data for ZrHx by the sab_calc module, which is developed based on the phonon expansion method (Squires, 2012; Wormald and Hawari, 2017)
It was shown that the TSL data given in ENDF/B-VIII.0 and JEFF-3.3 could introduce larger errors into the reactivity of the TRIGA reactors, because the TSL is not obtained from a realistic crystal structure of ZrHx
Summary
In the neutronics analysis of nuclear reactors, accurate prediction of the thermal neutron distribution has an important effect on behaviors of the reactors. In the work by Hartling et al (2018), it was found that in NJOY the inelastic scattering cross section is calculated on a fixed incident energy grid, and it has obvious effect on the Monte Carlo simulations. To solve this problem, an adaptive incident energy grid was implemented in the nuclear processing code NDEX (Wormald et al, 2020). The double-differential cross section can be calculated using the TSL data provided by ENDF as follows: σb 4πkBT. The midpoint is added to the final incident energy grid, and the interval-halving technique (Cacuci, 2010) is used to
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
