Validation of ENDF/B-VIII thermal neutron scattering data of heavy water by differential cross section measurements at various temperatures

Abstract

Temperature-dependent thermal neutron differential scattering cross sections for heavy water (D2O) were measured using a triple-axis spectrometer at the National Research Universal reactor located in Chalk River, Canada. The measurements were performed at temperatures from 22 to 85 °C and at atmospheric pressure, with incident neutron energies from 16 to 44 meV and scattering angles from 10 to 110°. The temperature range in the measurements covered the common D2O moderator conditions (65–70 °C and 1 atm pressure) in pressurized heavy-water reactors. The measured results were compared with the D2O data libraries from the ENDF/B-VII.1 evaluation and the recently released ENDF/B-VIII.0 evaluation. The experimental results indicate significant improvements in the new release compared to the previous ENDF/B-VII.1 release.