How to enrich uranium into fuel

Updated 1351 GMT (2151 HKT) November 24, 2013
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Iran and the P5+1, the five permanent members of the U.N. Security Council plus Germany, reached a deal on Sunday, November 24, to dial back Iran's ability to work toward a nuclear weapon. Click through for an overview of how enriched uranium is made. BEHROUZ MEHRI/AFP/Gett/FILE
Uranium, a partially radioactive metal found throughout the Earth's crust, is excavated from underground or open-cast mines. DAVID BOILY/AFP/Getty/FILE
The uranium is then extracted from the mined ore using a leaching agent at a chemical plant. FABIO MOTTA/AFP/Getty/FILE
Once extracted, the solid uranium oxide concentrate -- known as yellowcake -- needs to be converted to a toxic gas, known as Uranium Hexafluoride (UF6), before the next stage in the fuel-making process. BEHROUZ MEHRI/AFP/Getty/FILE
The concentration of the fissionable isotope in uranium, U-235, has to be increased to 3.5 percent for it to be useable in a nuclear reactor. Enrichment occurs when the UF6 gas is fed into centrifuges and spun at high speeds until the required level of U-235 is achieved. A nuclear bomb requires 90 percent enriched uranium. Office of the Presidency of the Islamic Republic of Iran/FILE
The enriched UF6 gas is transported to a fuel fabrication plant where it is converted to uranium dioxide (UO2) powder and pressed into small "pellets." These pellets are inserted into thin tubes to form fuel rods, which are sealed and assembled in clusters to form fuel assemblies for use in the core of a nuclear reactor. BEHROUZ MEHRI/AFP/Getty/FILE
Once inside a reactor the nuclei of uranium-235 atoms split and release energy. This energy is used to heat water and turn it into steam, which is used to drive turbines to generate electricity. IIPA via Getty/FILE