A model for predicting the annealing response of A553-B weld materials has been developed. This model assumes that the irradiation-induced shifts in the nil ductility transition temperature (ΔNDTT) and Charpy upper shelf energy (ΔUSE) are a result of the introduction of three types of defects into the alloy. The recovery of ΔNDTT and ΔUSE depends on the concentration of each defect remaining after the annealing treatment. The three defect types, including their diffusion constants, are assumed to be the same for all A533-B welds. However, the contribution of each defect type to ΔNDTT and ΔUSE depends on the chemical composition of the material and possibly the neutron fluence. Copper, nickel, manganese, and chromium were found to correlate with ΔNDTT, while sulfur and phosphorus appeared to correlate with ΔUSE. Once the relative contribution of each defect type is known, the recovery of ΔNDTT and ΔUSE is predicted based on diffusion calculations. Both the annealing temperature and time are accounted for in the calculations. The final model was compared with experimental data on three materials tested by Westinghouse Electric Corporation and two materials tested by the Naval Research Laboratory. The model accurately predicted the recovery of ΔNDTT for all five materials annealed at 343°C (650°F) to 454°C (850°F) for 24 to 336 h. The predicted recovery of ΔUSE was not as accurate as that of ΔNDTT.