Gas centrifuge enrichment

Fishman, A. M. A. I. Chem. E. Symposium Series No. 169, 73 (1977). Developments in Uranium enrichment, 43. The centar gas centrifuge enrichment project Economics and engineering considerations. 

Table 12.5 shows expected isotopic uranium contents which might be expected as product from cascade type (gaseous diffusion or gas centrifuge) enrichment facilities. While the highly enriched U is actually the target of these efforts one should also be able to verify the production of low enriched uranium. Columns 5 and 6 of Table 12.5 show the isotopic enrichments which would result from a 1000-1 mixture of namral U and low or high enriched U. Table 12.6 shows the ratios of the isotopes U and U relative to the in each mixture. The 0.6% isotopic shift in the ratio in the case of LEU-MIX should be detectable by today s technology. The 0.13% in ratio... 

The UgOg is put through a chemical conversion process to produce UFg (uranium hexafluoride) gas, which sublimates from a solid to a gas at 53°C (127°F) at one atmospheric pressure. The hexafluoride forms the feed for both the gaseous diffusion and the gas centrifuge enrichment processes. Cost of the conversion process is in the range of 10/kg of uranium product. 

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

I. D. Heriot, Cranium Enrichment by Gas Centrifuge, EUR 11486EN, for the Commission of the European Communities, Urenco Ltd., Luxembourg, Belgium, 1988. 

D. G. Avery and E. Davies, Uranium Enrichment by Gas Centrifuge Mills Boon Ltd., London, 1973. 

Uranium carbonates, 25 430-432 Uranium chlorides, 25 438-439 Uranium compounds, 25 421-434 handling, 17 529 Uranium dioxide, 25 422-423 Uranium-enrichment process gas centrifuge, 25 413-415 Uranium exploration, 25 398 URanium Extraction (UREX) process, 25 420... 

Whitley, S. A Summary of the Development of the Gas Centrifuge British Nuclear Fuels pic, Enrichment Division, Capenhurst, (June 1988). 

Avery, D. G., Davies, E., 1973 Uranium Enrichment by Gas Centrifuge (London, Mills Boon, Ltd.)... 

Fuel. The nuclear fuel cycle starts with mining of the uranium ore, chemical leaching to extract the uranium, and solvent extraction with tributyl phosphate to produce eventually pure uranium oxide. If enriched uranium is required, the uranium is converted to the gaseous uranitim hexafluoride for enrichment by gaseous diffusion or gas centrifuge techniques, after which it is reconverted to uranium oxide. Since the CANDU system uses natural uranium, I will say no more about uranium enrichment although, as I m sure you appreciate, it is a major chemical industry in its own right. 

UF4,is combined with fluorine gas to yield uranium hexafluoride, UF6 UF4(s) + F2fe) —> UF6(g). Uranium hexafluoride is a white crystalline solid at standard temperature and pressure, but it sublimes to a gas at 57°C. The U-235 in uranium hexafluoride can be enriched by several methods based on the difference in masses of the uranium isotopes. Two common methods are gaseous diffusion and gas centrifuge. 

Fluorine compounds from fluorite (fluorspar, CaF2) are used in water treatment (to suppress dental caries) and to make fluoropolymers (such as Teflon), lubricants, and refrigerants. Molten cryolite (Na3AlF6) is essential as a solvent for Al203 in the electrolytic production of aluminum metal, while the isotopic enrichment of uranium for nuclear power reactors is usually achieved by diffusion or gas centrifugation of volatile UF6. 

Jet nozzle enrichment Calutron Gas centrifuge Reprocessing solvent process... 

Enrichment of the Sy-isotope from the 0.711% in natural uranium to ca. 4% can proceed by gas diffusion, with a gas centrifuge and with separation nozzles. The separation nozzle process is no longer important. Pure uranium(VI) fluoride is utilized. 

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). 

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