Vast amounts Nuclear fuel cycle ore are mined to produce usable stocks of uranium due to the low concentration of uranium in the ores. The worldwide distribution of uranium ore is discussed. Next, the steps in preparing this material for processing in enrichment plants are described. Enrichment technologies, including gaseous diffusion, centrifuges, electromagnetic separation, and laser isotope separation, are described. The concept of the Separative Work Unit, or SWU, is introduced, and the mass balance calculations for an enrichment cascade are given. The proliferation potential for each of these schemes is described. Reactors are used to make plutonium, and the features making reactor types attractive or unattractive for weapon-grade plutonium production are described. Conversion of military material to civilian use is discussed, and proliferation risks in the waste stream are assessed.