UC Berkeley

The objective of the reported study is to develop the much-needed computational bridge for connecting the accelerated irradiation tests to the expected material performance in the future fission/fusion reactors. This new computational model serves as an alternative to traditional mean-field ODE-based reaction rate theory (RT) models which come with intrinsic disadvantages that cause simulations of complex microstructure evolution under multi-ion irradiation conditions to become prohibitively expensive to handle. Our stochastic cluster dynamics (SCD) model enables efficient simulation of complex damage accumulation in materials irradiated to practical damage doses with reasonable computing time and resources. SCD obviates the need to solve the exceedingly large sets of ODEs and relies instead on the sparse stochastic sampling from the underlying kinetic Master Equation (ME). We then apply the SCD model to simulate multi-ion irradiation experiments of Fe3+, He+ and H+ on bcc-Fe and provide explanation to the synergistic effects observed in the triple-beam experiments carried out at the Japanese Takasaki Ion Accelerator for Advanced Radiation Application (TIARA) facility. We also propose the employment of pulsed single/dual-beam irradiations as possible alternatives to the steady triple-beam irradiation for investigation of materials used for nuclear applications.