Solute diffusion in alloys is mostly mediated by defect-driven mechanisms. In irradiated materials, the considerably large point-defect population may enhance or even induce solute diffusion. In particular, in case of a binding solute-defect interaction, kinetic correlation effects may arise and lead to the formation of nanoscopic solute-defect complexes. The latter may be detrimental for the alloy structural integrity. In this talk we present a novel method for predicting the arising of solute-defect flux coupling in most types of alloys. The model combines first-principles calculations with an analytical mean field model and allows for the computation of solute transport and diffusion coefficients at low temperatures, which are usually inaccessible by means of experiments. The results for model dilute alloys will be presented, and implications on the structural integrity of nuclear reactor pressure vessel steels will be discussed.