Micromechanical modeling of neutron irradiation induced changes in yield stress and electrical conductivity of zircaloy

A micromechanical model of the changes in electrical conductivity of zircaloy induced by neutron irradiation is developed. The approach is illustrated on example of High Flux Isotope Reactor (HFIR). First, HFIR reactor core has been simulated by MCNPX v2.4 code and neutron flux-energy spectrum has been extracted. The spectrum is used as the main input in SPECTER code to calculate the displacement per atom (dpa), primary knock out atoms (pka) distribution, spectral averaged kerma (MACKLIB), etc. in dependence on radiation time. These results are used to estimate variation of the yield stress of zirconium as function of radiation time applying experimental dependence of the yield stress on dpa (available in literature). Finally, the cross-property connection between yield stress and electrical conductivity is applied to estimate the latter as a function of the irradiation time.