U.S interest in enriching uranium, to increase the concentration of the fissile U-235 isotope, began prior to the Manhattan Project and continued in through World War II as a means of deploying nuclear weapons. Uranium enrichment is now used for peaceful purposes to supply fuel to nuclear power reactors. From the 1940’s to today, Oak Ridge has been a national center for uranium enrichment technology development and deployment. The development history in Oak Ridge has including gaseous diffusion, electromagnetic, thermal diffusion, laser, and centrifuge based technologies. ORNL has continued this legacy in development and analysis of new techniques, including a new Electromagnetic Isotope Separation system and U.S. based centrifuge designs.