Primary knock on atom spectra, gas production and displacement cross section for tungsten and chromium irradiated with neutrons at energies up to 14.1 MeV

Highlights: • Excitation function of (n,el), (n,2n), (n,p) & (n,α) reaction channels on ¹⁸⁴W have been predicted to select the appropriate nuclear models. • Recoil spectra or PKA of all the possible reaction channels have been predicted. • Gas production cross-section has been predicted for natural tungsten and chromium. • Displacement cross-section with the NRT approach has been predicted using PKA data. • Discrepancies between the calculated data and displacement cross-section from ENDF VIII, JEFF-3.3 and TENDL-2017 data have been discussed. - Abstract: In the ITER and other proposed fusion reactors, chromium and tungsten are proposed as first wall materials. Fusion of DT plasma will produce neutrons of 14.1 MeV energy. Nuclear reactions of fusion reactor material with such high energy neutrons lead to the displacement cascades and gas production in the reactor materials. All probable reaction channels such as (n,n'), (n,2n), (n,p), (n,α) and (n,d) are open for the interactions of these neutrons with tungsten and chromium. In the present study, energy spectra of recoils or PKA, gas production and displacement cross section for tungsten and chromium at neutrons of up to 14.1 MeV energy have been predicted using the appropriate nuclear models in the TALYS-1.8 code. In the cross section and PKA calculations, the contributions from possible reaction mechanisms such as direct, pre-equilibrium, and compound nuclear mechanisms have been considered. Calculated energy spectra of protons, alpha particles, and outgoing neutrons have been compared with recent ENDF-VIII, JEFF-3.3 and TENDL-2017 data libraries and discrepancies among them have been discussed. PKA data from each reaction channels have been calculated. PKA data have been used to predict the displacement cross-section with the Norgett, Robinson, and Torrens (NRT) approach. Calculated displacement cross section data of chromium and tungsten have been compared with existing data.