New Evaluation and Validation Towards Neutron Reaction Data on Chromium Isotopes at Incident Energies Below 200 MeV

Abstract Chromium (Cr) serves as an indispensable structural material in accelerator - driven systems (ADS) and Generation IV reactors, where the precision of its neutron reaction data is important for ensuring reactor safety and operational reliability. However, significant discrepancies persist in both experimental data and evaluations for key reaction channels, such as (n, p) and (n, 2n), across the chromium isotopes 50,52,53,54Cr. This study presents a novel evaluation and validation of neutron reaction data for these isotopes at incident energies below 200 MeV, incorporating 571 experimental datasets from EXFOR covering cross sections, angular distributions, energy spectra, and double - differential cross sections. The newly evaluated data provide more reliable key cross sections: the 52Cr(n,2n) cross section resolves discrepancies and supports H. Liskien et al.'s data; the 52Cr(n, p) cross section aligns well with natural chromium data across all energies, and is validated by competition analysis. The results accurately replicate double differential cross sections and energy spectra, with neutron emission spectra matching experimental peaks and charged - particle spectra agreeing with measurements for 50,52Cr. Moreover, the abundance - weighted sum of (n, p) and (n, 2n) cross sections for chromium isotopes agrees well with natural chromium data, confirming systematic consistency. All evaluations are validated using 62 ICSBEP 2014 benchmark facilities with keff sensitivity to chromium neutron data >1%. For the PMI002_01 experiment, calculated keff decreased by approximately 1000 pcm relative to CENDL - 3.2, improving agreement with the benchmark; in the OKTAVIAN shielding benchmark, the neutron leakage spectrum also produces experiments well.