Modeling the microstructural evolution in bcc-Fe during irradiation using kinetic Monte Carlo computer simulation

Abstract

Kinetic Monte Carlo (KMC) simulations of defect accumulation in neutron-irradiated bcc-Fe are presented. Comparisons of the KMC simulations with the recent experimentals are made to discuss the validity of the proposed KMC model. Then, the effect of environmental variables such as irradiation temperature, dose rate, and neutron spectrum is studied using the technique. The magnitude of dose rate effect is irradiation-temperature dependent, and it is found that a threshold dose rate, below which defect accumulation is not affected by the difference of dose rate, exists when irradiated at 600 K. An evaluation of the number of vacancy jumps of both irradiation-induced vacancies as well as thermal vacancies is done to study a possible effect of dose rate on a solute diffusion in bcc-Fe. The results show that the total number of vacancy jumps is dose rate dependent at very low and high dose rates while there is a dose rate independent region in between.