
Diagram of a gas centrifuge.
The 'gas centrifuge' is a hyper-
centrifuge used to separate gases. Its most common use is to produce
enriched uranium. For uranium enrichment it requires far less
energy to achieve the same separation than the older
gaseous diffusion process that it has mostly replaced.
Uranium Enrichment
Enrichment process
The gas centrifuge uranium enrichment process uses a large number of rotating cylinders in series and parallel formations. Centrifuges are interconnected to form trains and
cascades. In this process,
uranium hexafluoride (UF
6) gas is placed in a cylinder and rotated at a high speed. This rotation creates a strong centrifugal force so that the heavier gas molecules, containing
uranium-238 (U-238), move toward the outside of the cylinder and the lighter gas molecules, containing
uranium-235 (U-235), collect closer to the center. The stream that is slightly enriched in U-235 is withdrawn and fed into the next higher stage, while the slightly depleted stream is recycled back into the next lower stage. Significantly more U-235 enrichment can be obtained from a single unit gas centrifuge than from a single unit gaseous diffusion stage.
Countries operating large cascades

A cascade of gas centrifuges at a United States enrichment plant.
Large cascades of gas centrifuges are operated by
France,
Germany, the
United Kingdom,
Netherlands, and
China to produce enriched uranium both for domestic use and for export, and by
Japan for domestic use. A demonstration gas centrifuge plant is being built at
Piketon, Ohio in the
United States by
USEC Inc. for operation in 2007, and a full-size plant is planned for operation in 2012.
Pakistan's nuclear program developed the P1 and P2 centrifuges -- the first two centrifuges that Pakistan deployed in large numbers. The P1 centrifuge uses an
aluminium rotor, and the P2 centrifuge uses a
maraging steel rotor, which is stronger, spins faster, and therefore enriches more uranium per machine than the P1 centrifuge's aluminium rotor.
Recently the
President of Pakistan allegedly revealed an account of how the country's top nuclear scientist,
A.Q. Khan, had stolen diagrams of centrifuges while working at
URENCO in
Netherlands.
Iran has constructed a gas centrifuge uranium enrichment plant near
Natanz, which is to be used for
Iran's nuclear program.
[1] In April 2007, President
Mahmoud Ahmadinejad announced that the plant had started enrichment operations.
See also
★
Isotope separation
★
Zippe-type centrifuge
External links
★
Annotated bibliography on the gas centrifuge from the Alsos Digital Library
★
History of the Centrifuge
★
What is a Gas Centrifuge?