Gas centrifuges are now the method of choice for enriching uranium. These spinning cylinders are used to increase the concentration of U-235, the fissionable isotope of uranium, to make it usable as fuel in nuclear reactors or as warheads in nuclear weapons. This section describes how gas centrifuges work, discusses the theoretical principles of isotope separation and considers the engineering challenges in constructing and optimizing the machines. Furthermore, this section looks at what is needed to operate an entire enrichment plant (how centrifuges operate in cascades), and how the possibility of dual use of enrichment technology creates opportunities for nuclear weapons proliferation.
Gas centrifuges enrich uranium for commercial nuclear reactors. The same machines can enrich uranium up to the higher levels needed for nuclear weapons. The global proliferation of nuclear fuel enrichment capability raises serious risks of increased nuclear weapons proliferation.
In a single step, no centrifuge can enrich enough material to the degree required for nuclear reactor fuel. Therefore, centrifuges are connected into cascades. The difference between reactor fuel and nuclear weapon cascades is how the individual centrifuges are interconnected.