Isotope separation centrifuge based

A second type of apparatus based on the pressure diffusion effect is the separation nozzle. Pressure gradients in a curved expanding jet produce an isotopic separation similar to that in a centrifuge. The separation effect obtained with a single jet is relatively small, and separation nozzle stages, similar to gaseous diffusion stages, must be used in a cascade to realize most of the desired separations. 

Since the different isotopes of an element all have the same chemical properties, they can be quite difficult to separate. The separation techniques used to separate different isotopes are thus based on their differences in mass, rather than on differences in chemical properties. Some of the methods used include separation by diffusion in the gas or liquid phases, centrifugation, ionization and mass spectrometry, or chemical methods based on differences in reaction rates due to different atomic masses. 

The classical methods of isotope separation on a large, technical scale, such as thermal diffusion, or gas centrifuge techniques are expensive because they demand costly equipment or consume much energy [14.11], New techniques based on a combination of laser spectroscopy with photochemistry may considerably reduce the costs. Up to now several methods have been proposed and some of them already proved their feasibility in laboratory experiments. The extension to an industrial scale, however, demands still more efforts and many improvements. ... 

The separation of chemical isotopes is based on small differences in their physical and chemical properties. For the lower-mass isotopes, chemical exchange, distillation, and electrolysis have been used. For the higher-mass isotopes, techniques based on mass have been used, including gaseous diffusion, centrifugation, thermal diffusion, and ion activation.29,30 A newer method uses lasers that produce coherent light tuned to the specific wavelength of a vibration bond related to the desired isotope in an atom or molecule. This technique is still under development but... 

An important example of pressure diffusion (1) is the current worldwide competition to perfect a low-cost gas centrifuge capable of industrial-scale separation of the and U, gaseous hexafluoride isotopes. To date, atomic bomb and atomic power self-sufficiency has been limited to major powers since the underdeveloped countries have neither the money nor an industrial base to build the huge multi-billion dollar gaseous diffusion (2) plants currently required for uranium enrichment. In these plants, typified by the U.S. Oak Ridge Operation, and Up6 are separated by forcing a gaseous mixture of the... 

---