The nuclear fuel cycle uses uranium in different chemical and physical forms. As illustrated below, this cycle typically includes the following stages:

Uranium recovery to extract (or mine) uranium ore, and concentrate (or mill) the ore to produce "yellowcake"
Conversion of yellowcake into uranium hexafluoride (UF₆)
Enrichment to increase the concentration of uranium-235 (U²³⁵) in UF₆
Fuel fabrication to convert enriched UF₆ into fuel for nuclear reactors
Use of the fuel in reactors (nuclear power, research, or naval propulsion)
Interim storage of spent nuclear fuel
Reprocessing of high-level waste (currently not done in the U.S.)^[1]
Final disposition (disposal) of high-level waste

^[1] Neither a reprocessing facility nor a Federal waste repository is currently approved (licensed) in the United States, and spent fuel is in interim storage. See High-Level Waste Disposal.