Calculation of displacement, gas, and transmutation production in stainless steel irradiated with spallation neutrons

Abstract

Calculations using the high-energy transport code LAHET have been made for the production of displacements, helium gas, and transmuted atoms for stainless steel (Fe-18 wt% Cr-10 wt% Ni) irradiated with spallation neutrons at energies of 100 to 1600 MeV. The damage energy cross section increased from about 250 to 350 b keV for increasing neutron energies from 100 to 1600 MeV with a spallation spectrum average of 281 b keV. For a displacement threshold energy of 33 eV, the corresponding spectrum-average displacement cross section is 3400 b. The PKA spectrum was found to be fairly independent of the incident neutron energy, with an average damage energy of 0.25–0.30 MeV. The helium production cross section increased monotonically with increasing neutron energy with a spectrum average of 0.32 b. The maximum transmutation yield was observed near manganese ( Z = 25), corresponding to a production cross section of about 0.2 b. Relevance to fusion materials is discussed.