U.S. production of uranium concentrate fell 13% to 2.9 million pounds in 2016, compared to 2015, and was the lowest level since 2005, according to U.S. Energy Information Administration. Last year, production was less than 7% of the peak production level of 43.7 million pounds in 1980.
Most of the uranium used in U.S. nuclear power reactors is imported. In 2015, owners and operators of U.S. nuclear plants purchased 57 million pounds of uranium. Almost half of this uranium was purchased from Canada and Kazakhstan, providing 17 million pounds and 11 million pounds, respectively.
In the United States, uranium concentrate was produced at seven facilities in three states. “Five facilities in Wyoming and one in Nebraska produced uranium concentrate at in-situ (or in place) leach plants. These plants extract uranium oxide from underground source rock using an acidic water-based solution pumped into the source rock through injection wells. The solution is then extracted and uranium chemically separated out,” according to the EIA. In Utah, the White Mesa Mill produces uranium by crushing and grinding uranium ore into a powder. The uranium is separated from other minerals using chemicals.
“The concentrated uranium product is typically a bright yellow or orange powder called yellowcake,” according to the EIA. “Yellowcake is later converted into uranium hexafluoride (UF6) gas at a converter facility and then enriched to produce certain isotopes of uranium.” Uranium-238 is the most common isotope, accounting for more than 99% of natural uranium. Uranium-235 and uranium-234 are less common naturally occurring isotopes.
“To produce enriched uranium, different isotopes are separated at enrichment facilities either by centrifugal process or by gaseous diffusion,” the EIA shows. “The enriched UF6 is then converted into uranium dioxide powder, formed into fuel pellets and loaded into the fuel assemblies used to fuel nuclear power plants.”