There are ~65 Trillion tons of uranium in Earth's crust. This dissolves into sea water to maintain an equilibrium concentration. It takes 18.6 tons of natural

There are ~65 Trillion tons of uranium in Earth's crust. This dissolves into sea water to maintain an equilibrium concentration. It takes 18.6 tons of natural uranium to produce 1 TWh of electricity with light water reactors. The world consumes ~30,000 TWh each year. 65 Trillion / (18.6 * 30,000) = 1x10^8 years worth of uranium with present day technology, no elves required.