These ultra-centifuges spin at 1000-1500 revolutions per second and can easily break when not carefully controlled. The Zippe-type centrifuges (http://en.wikip

These ultra-centifuges spin at 1000-1500 revolutions per second and can easily break when not carefully controlled. The Zippe-type centrifuges (http://en.wikipedia.org/wiki/Zippe-type_centrifuge http://en.wikipedia.org/wiki/Zippe-type_centrifuge) are probably used in Natanz for enrichment. During the spinning, a temperature gradient of 300C is applied to the cylinder which induces a convection inside (filled with uranium-fluoride gas). The lighter fraction collects at the top and is captured. These centrifuges operate in a vacuum, and can turn frictionless due to magnetic bearing.