Gaseous-diffusion plants

ACS Symposium Series American Chemical Society Washington, DC, 1975. 

Almost 60,000 moles of natural abundance uranium flow through the cascade, at the feed stage for each mole of 90% 235u withdrawn. 

9 Is of major Importance for estimating the size and cost of an Isotope separation plant. It Indicates that the total flow Is a product of two factors the first of these, proportional to l/(a-l) Is a function only of the elementary separation factor which Is determined by the separation process used. The second factor [In square brackets], which Is usually called the separative duty or separative work units (S.W.U.) Is a function only of quantities and concentrations of feed, product, emd waste. It has the same dimensions as those used for the quantities of material, and Its value Is Independent of the process used to accomplish the separation task. The significance of the magnitude of the elementary factor Is Immediately apparent a two-fold reduction In (a-1) requires an Increase In the total flow by a factor of 4. Since for a gaseous diffusion process, the total flow rate Is closely related to the total area of porous barriers, the total pumping capacity and the total power consumption required, all the associated costs vary proportionately. 

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R. L. Earrar, Jr., and E. J. Barber, Some Considerations in the Handling of Fluorine and the Chlorine Fluorides, report K/ET-252, Oak Ridge Gaseous Diffusion Plant, Oak Ridge, Term., 1979. 

Data on New Gaseous Diffusion Plants, U.S. DOE Oak Ridge Operations Office, ORO-685,1972. 

The need for a large number of stages and for the special equipment makes gaseous diffusion an expensive process. The three United States gaseous diffusion plants represent a capital expenditure of close to 2.5 x 10 dollars (17). However, the gaseous diffusion process is one of the more economical processes yet devised for the separation of uranium isotopes on a large scale. 

The optimum pressure level for gaseous diffusion operation is also determined by comparison at some pressure level the decrease ia equipment size and volume to be expected from increasing the pressure and density is outweighed by the losses that occur ia the barrier efficiency. Nevertheless, because it is weU known that the cost of power constitutes a large part of the total cost of operation of gaseous diffusion plants, it can perhaps be assumed that a practical value of r does not differ gready from the above optimum. Inclusion of this value ia the preceding equations yields... 

Plant Operation and Costs. The operation and economics of the three United States gaseous diffusion plants miming ia 1972 is discussed ia References 29 and 30. These plants were operated as a single gaseous diffusion complex such that iaterplant shipments occurred so as to optimize the overall system. Independent operation of the plants would have resulted ia about a 1% loss ia separative work. 

In 1985, owiag to the declining demand by the nuclear power industry for enriched uranium, the Oak Ridge gaseous diffusion plant was taken out of operation and, subsequently, was shut down. The U.S. gaseous diffusion plants at Portsmouth, Ohio and Paducah, Kentucky remain ia operation and have a separative capacity of 19.6 million SWU (separative work unit) per year which as of this writing is not fully utilized. 

From equation 60 one can obtain a theoretical power requirement of about 900 kWh/SWU for uranium isotope separation assuming a reasonable operating temperature. A comparison of this number with the specific power requirements of the United States (2433 kWh/SWU) or Eurodif plants (2538 kWh/SWU) indicates that real gaseous diffusion plants have an efficiency of about 37%. This represents not only the barrier efficiency, the value of which has not been reported, but also electrical distribution losses, motor and compressor efficiencies, and frictional losses in the process gas flow. 

The cost of enriched material from a gaseous diffusion plant depends both on the cost of separative work and of feed material. It can be seen from equation 15 that if the optimum tails concentration from a gaseous diffusion plant is 0.25%, the ratio of the cost of a kg of normal uranium to the cost of a kg of separative work equal to 0.80 is impfled. Because the cost of separative work in new gaseous diffusion plants is expected to be about 100/SWU, equation 16 gives the cost per kg of uranium containing 4% as about 1,240. 

AEC Gaseous Diffusion Plant Operations, USAEC Report No. ORO-684, U.S. Atomic Energy Commission, Washington, D.C., Jan. 1972. 

Taylor, F.G., S.R. Hanna, and P.D. Parr. 1979. Coohng tower drift studies at the Paducah, Kentucky gaseous diffusion plant. U.S. Dep. Ener. Corf. 790109-1, Oak Ridge National Lab. 31 pp. 

Fig. 8.5 The K-25 Gaseous Diffusion Plant at Oak Ridge, TN is no longer operational. This photograph conveys some sense of the extremely large scale of this operation (Photo credit. US Department of Energy and Knoxville News Sentinel, Oct. 17, 2004)...

In the USSR also, inorganic membranes were developed and gaseous diffusion plants were constructed to meet the needs for enriched uranium. For understandable reasons, very little is known of these developments. 

Cragle DL, Hollis DR, Newport TH, et al. 1984. A retrospective cohort study among workers occupationally exposed to metallic nickel powder at the Oak Ridge Gaseous Diffusion Plant. In Sunderman FW Jr, Aitio A, Berlin A, eds. Nickel in the human environment. lARC scientific publication no. 53. Lyon, France International Agency for Research on Cancer 57-64. 

Goldbold JH, Tompkins EA. 1979. A long-term mortality study of workers occupationally exposed to metallic nickel at the Oak Ridge Gaseous Diffusion Plant. J Occup Med 21 799-806. 

Researchers used the 1998 demonstration of the DeHg process on wastes from the DOE s Portsmouth Gaseous Diffusion Plant to estimate the unit costs associated with the treatment... 

TABLE 1 Total Costs for the ISCOR Demonstration at the U.S. DOE Portsmouth Gaseous Diffusion Plant in Piketown, Ohio... 

In 1993, Geo-Con, Inc., first used the shallow soil mixing/thermaUy enhanced vapor extraction (SSM/TEVE) technology at the Portsmouth Gaseous Diffusion Plant. It has since been used at several other sites to accelerate contaminant volatilization (D14483M, p. 2). 

At the U.S. Department of Energy s (DOE s) Portsmouth Gaseous Diffusion Plant in Ohio, treatment of 20,000 yd of soil cost approximately 3.5 million (D10096Z, p. 10). 

In 1996, a field demonstration of horizontal recirculation wells was conducted at the X-701B site of the Portsmouth Gaseous Diffusion Plant in Piketon, Ohio. Using directional drilling methods, two horizontal wells 234 ft long were installed to a depth of 32 ft. Design and construction costs were estimated to be 1.43 million (D188709, p. 16). 

Portsmouth Gaseous Diffusion Plant, Piketon, OH, wastewater (P) TCE 1996 4,000,000 for installation... 

Geiger (C and M) Oil Superfund Site, Charleston, South Carolina British Petroleum, Pumpherston Station, Scotland Wisconsin Fuel and Light, Manitowoc, Wisconsin Portsmouth Gaseous Diffusion Plant, Piketon, Ohio Masselink Electroplating, Grand Rapids, Michigan 70/yd 83/yd 135/yd 8000 daily rate to conduct test 87/yd ... 

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