Onsager's analysis of the hydrodynamics of fluid circulation in the boundary layer on the rotor wall of a gas centrifuge is reviewed. The description of the flow in the boundary layers on the top and bottom end caps due to Carrier and Maslen is summarized. The method developed by Wood and Morton of coupling the flow models in the rotor wall and end cap boundary layers to complete the hydrodynamic analysis of the centrifuge is presented. Mechanical and thermal methods of driving the internal gas circulation are described. The isotope enrichment which results from the superposition of the elementary separation effect due to the centrifugal field in the gas and its internal circulation is analyzed by the Onsager- This manuscript was printed from originals provided by the author.
A. INTRODUCTIONUranium enrichment is an essential component of nuclear fuel cycles based upon light water reactors.For more than thirty years, the uranium enrichment industry has been based solely on gaseous diffusion technology.Because of the substantial electrical power requirements of this process, the gas centrifuge method, which requires only about 5% of the power for comparable enrichment, has been selected for most additional capacity.The early theoretical work on the gas centrifuge is presented in the book by Cohen(l). The recent books by Avery and Davies( 2 ), Villani (J) and Benedict and a1( 4 ) provide more up-to-date discussions, and Soubbaramayer(S) has summarized the current status of non-U.S. theoretical work. Summaries of early hydrodynamic analyses and separation theory are presented in ref.( 6 ) and a semi-technical description of the device is given in ref. (7).There are many reasons for engaging in theoretical analysis of a gas centrifuge. First, such calculations can be used to guide experiments, which for a fully-instrumented test machine, are quite costly. Second, they provide an understanding of ho\v the flow affects isotope separation and may suggest means of altering the flow profiles to improve performance. Third, they permit an assessment of off-optimum performance of the centrifuge. Finally, they can be used in engineering cost optimization studies, the object of which is to design a machine and operate it so that the cost per unit of separative power is a minimum. This last feature of the theory is especially important, because the large number of parameters controlling the internal flow (and hence the separation) makes experimental optimization expensive and tedious. Because of the large scale of the uranium enrichment industry, even a few percent improvement in a separative power of a device (at no expense) means yearly saving of many millions of dollars in the cost of electricity generated by light water reactors. Figure 1 shows an early gas centrifuge. The current models are of the same general type but are larger and are capable of much higher speeds.-1-Machines with diameters as large as 24 inches have been tested. Figure 2 is a schematic of the centrifuge. An electric motor resting on the bo...