Thermal neutron scattering measurements and modeling of yttrium-hydrides for high temperature moderator applications. (July 2021)

• Record Type: Journal Article
• Authors: Chapman, Chris W.; Ramić, Kemal; Hu, Xunxiang; Brown, Jesse M.; Arbanas, Goran; Kolesnikov, Alexander I.; Abernathy, Douglas L.; Daemen, Luke; Ramirez-Cuesta, Anibal (Timmy) J.; Cheng, Yongqiang; Stone, Matthew B.; Liu, Li (Emily); Danon, Yaron
• Is Part Of: Annals of nuclear energy. Volume 157(2021)
• Publication Date: 2021-07
• Subjects: Thermal neutron scattering -- Yttrium hydride -- Temperature dependent effective potential; Nuclear energy -- Periodicals; Nuclear engineering -- Periodicals; 621.4805
• DOI: 10.1016/j.anucene.2021.108224
• Languages: English
• ISSNs: 0306-4549

Abstract

Abstract: Thermal neutron scattering measurements of yttrium hydride from 5 to 1, 200 K were conducted to determine the change in inelastic scattering as a function of temperature and to probe for anharmonic effects. Additionally, measurements on samples of YH x from x = 1.62 to 1.90 were done to determine the effects of varying hydrogen concentration on the inelastic spectra. Changes in temperature affected the inelastic spectra in unanticipated ways, indicating that there are anharmonic effects, whereas hydrogen concentration did not significantly affect the inelastic spectra. These measurements were compared against the ENDF/B-VIII.0 thermal scattering files of YH2, as well as new thermal scattering files created by using the stochastic temperature-dependent effective potential (s-TDEP). Both libraries were found to be in good agreement with the experimental data at lower temperatures. At higher temperatures, the s-TDEP method is better at predicting the experimentally observed softening of phonon modes in acoustic and optical regions.