Joint economic and physical constraints on nuclear power: how much uranium would be needed to decarbonize electricity supply?

Abstract

A new uranium supply and usage analysis takes into account growth in physical demand for electricity, both before and after decarbonization. It also models the economic willingness of investors to build the required reactors as a profit-maximizing decision. The analysis computes the optimum path of investment and disinvestment in one or more uranium-based fuel cycles as dynamic profit maximization under physical constraints, and the resulting economic decisions are compared with physical decarbonization goals. Investor decisions prove to be insensitive to the electricity price (and hence to higher carbon tax) above a low threshold. Above that price threshold, their decisions on reactor investment are dominated by the total supply of uranium and the speed at which reactors can be built. In order to pay for the very large generating capacity needed, profit-maximizing investors seem to need of the order of 36 M tons of uranium reserves to use (some seven times the world's presently identified reserves). Even given this supply, they will limit their maximum investment in capacity if the build rate of reactors is too slow. If the world does choose to decarbonize, it will be necessary to manage uranium prospecting, and reactor building, purchase and operation as an interdependent system, and there will be a steep task of uranium exploration over the next decade or two.