Process
In the vortex separation process a mixture of uranium hexafluoride gas and hydrogen is injected tangentially into a tube at one end through nozzles or holes, at velocities close to the speed of sound. The tube tapers to a small exit aperture at one or both ends. This tangential injection of gas results in a spiral or vortex motion within the tube, and two gas streams are withdrawn at opposite ends of the vortex tube; centrifugal force providing the isotopic separation. The spiral swirling flow decays downstream of the feed inlet due to friction at the tube wall. Consequently, the inside diameter of the tube is typically tapered to reduce decay in the swirling flow velocity. This process is characterized by a separating element with a very small stage cut (the ratio of product flow to feed flow) of about 1/20, and high process-operating pressures.
Due to the extremely difficult plumbing required to link stages together, the design was developed into a cascade design technique (dubbed Helikon), in which 20 separation stages are combined into one module, and all 20 stages share a common pair of axial-flow compressors. A basic requirement for the success of this method is that the axial-flow compressors successfully transmit parallel streams of different isotopic compositions without significant mixing. A typical Helikon module consists of a large cylindrical steel vessel housing the 20 separator assemblies, along with two compressors (one mounted on each end), and two water-cooled heat exchangers.
Advantages of this process are a lack of criticality concerns due to the highly diluted feedstock and suitability for batch processing. This means Helikon-type plants can be relatively small, making the technology a nuclear proliferation concern.
Read more about this topic: Helikon Vortex Separation Process
Famous quotes containing the word process:
“Consumer wants can have bizarre, frivolous, or even immoral origins, and an admirable case can still be made for a society that seeks to satisfy them. But the case cannot stand if it is the process of satisfying wants that creates the wants.”
—John Kenneth Galbraith (b. 1908)
“Rules and particular inferences alike are justified by being brought into agreement with each other. A rule is amended if it yields an inference we are unwilling to accept; an inference is rejected if it violates a rule we are unwilling to amend. The process of justification is the delicate one of making mutual adjustments between rules and accepted inferences; and in the agreement achieved lies the only justification needed for either.”
—Nelson Goodman (b. 1906)
“I believe that history might be, and ought to be, taught in a new fashion so as to make the meaning of it as a process of evolution intelligible to the young.”
—Thomas Henry Huxley (1825–95)