Evaluations and calculations of neutron reactions on 238U up to 20 MeV

Abstract

In order to improve the quality of neutron data for U in CENDL, considering the impact of new measurements, a brand-new evaluation of the complete set of neutron induced U reaction data up to 20 MeV has been performed. Important reactions, such as (n,tot), (n,γ), (n,f), (n,2n) and (n,3n) reaction cross sections and average number of fission neutrons have been evaluated based on experimental data analysis. Also, using existing optical model potential parameters, new theoretical calculations based on Hauser-Feshbach and pre-equilibrium model have been carried out. Resonance parameters and prompt fission neutron spectrum from ENDF/B-VIII.0 have been adopted. Guided by integral benchmark, (n,inl), (n,γ) and (n,f) reaction cross sections have undergone multiple adjustments, leading to a noticeable improvement in data quality, as indicated by final benchmark results.