Abstract
Neutron irradiation can severely impact the mechanical behavior of nuclear structural materials. Irradiation introduces a high density of nanometric defects that block dislocation motion and result in hardening and a loss of ductility often associated with the onset of localized plastic flow in a highly heterogeneous manner. In our hierarchy of numerical methods used to understand and quantify mechanical property degradation under irradiation, discrete dislocation dynamics (DD) provides a window into the time and length scales where critical interactions between dislocations and defects occur. In the present chapter, we discuss the current state of the art of DD simulations applied to irradiation scenarios, introducing the theoretical models devised to deal with dislocation-defect interactions, crystal structure particularities, and the most salient aspects of several highlighted applications. We also discuss current limitations and what new understanding has been gained vis-a-vis serviceable nuclear materials using these techniques.