The economics of enriched-uranium production in USAEC facilities have been analyzed and the equations of an optimizing economic model of the enriched-uranium industry developed. The objective junction that is minimized by the model is the present value of the combined controllable costs of the USAEC and of the users of enriched uranium. The economic system considered is thus unusually comprehensive and the optimization problem correspondingly complex. A basic consideration in developing the optimum operating strategy is that the existing AEC investment in diffusion plant and feed stockpiles may be used to preproduce economically some of the future requirements for enriched uranium. The model has been used extensively in USAEC enriched-uranium production planning.