Benchmark test of activation cross-sections for Cr and Ni using the quasi-monoenergetic neutrons below 35 MeV

摘要

Continuing the experimental tests of neutron activation cross-section data the activation of Chromium and Nickel was investigated using fast quasi-monoenergetic neutrons from the NPI cyclotron-based neutron source. These nuclides present an important component of the MoNiCr-alloy (the variant of Hasteloy steel for Fluoride-Molten-Salt-Reactor systems); Cr stems also the constituent of a low-activation Eurofer-97 steel (fusion technology). Sample foils (Cr-Ni alloy) were irradiated by neutrons with spectrum peaked at 19.0, 24.3, 26.6 and 35.6 MeV. They were generated in the source reaction p-~(7)Li by protons at energies of 22.0 27.2, 29.5 and 37.5 MeV, respectively. After irradiation of samples, the induced gamma activities were measured at various cooling times employing the gamma spectrometry method based on the HPGe detector technique. The analysis of resulting specific activities was carried out in terms of C/E ratio (E - measured reaction rate, C - the predicted value calculated for the neutron spectrum and the corresponding cross section from EAF-2007 library). The neutron flux and spectra at sample positions were calculated using double-differential cross-section data of the source reaction ~(7)Li(p,xn) measured by other authors. Resulting C/E data of observed isotopes are compared with results of integral benchmark experiment carried out at similar energy range using white-spectrum neutrons from the NPI p-D_(2)O neutron source.