Gas centrifuge process

The UFg is then isotopicaHy enriched by gaseous diffusion or gas centrifuge processes for nuclear appHcations. 

It should be noted that the separation factor for the centrifuge process is a function of the difference in the mol wts of the components being separated rather than, as is the case in gaseous diffusion, a function of their ratio. The gas centrifuge process would therefore be expected to be relatively more suitable for the separation of heavy molecules. As an example of the equiUbrium separation factor of a gas centrifuge, consider the Zippe centrifuge, operating at 60°C with a peripheral velocity of 350 m/s. From equation 68, OC is calculated to be 1.0686 for uranium isotopes in the form of UF. ... 

The current gas centrifuge process goes back to a study by Gemot Zippe (Ref 5). According to theory, the maximum separative work which a gas centrifuge can produce per unit time is ... 

The gas centrifuge process uses long multipy overcritically rotating cylinders, in which the heavy uranium isotope is enriched at the cylinder wall and the lighter isotope is enriched at the center of the centrifuge. Enrichment to 3 to 5% is achieved in less than ten stages connected in series. The energy consumption is ca. 50 kWh/kg SWU (SWU = separation work units). 

There are three procedures that are used for the enrichment of U (Choppin and Rydberg 1980 Pickert and Zech 1981) (1) gas diffusion process, (2) gas centrifugation process, and (3) nozzle process. All three processes use the fact that UFg with the isotope U is lighter by three mass units than the compound with U. 

There also have been gaseous diffusion plants built in other coimtries, some still in operation, but the gaseous diffusion process is gradually being replaced by the gas centrifuge process. Another method of enrichment, laser isotopic separation, has generated interest in recent years. 

In June 2010, the Stuxnet computer worm was discovered by a Belarus-based antivirus software vendor called Virus BlokAda. The Stuxnet worm had been used to attack the Natanz, Iran, uranium enrichment plant - a gas centrifuge process - since 2008. It caused disruption and delays to Iranian enriched uranium production, by introducing malware into Siemens S7 controllers used in the Centrifuge Drive System. 

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