Uranium is utilized as a source of fuel in nuclear power plants as well as nuclear weapons. Despite the fact that the chemical properties of two isotopes are almost exactly the same as one another, the difference in the total number of neutrons present in the nucleus of an isotope can have a significant impact on its nuclear properties. This is the case with uranium, which is composed of two isotopes: uranium-238 (also written as U-238), which accounts for the majority of the element, and uranium-235, which accounts for only 0.7% of natural uranium. Uranium-238 accounts for the majority of the element.(As a direct consequence of this property, materials like uranium-235 and plutonium are referred to as fissionable.)The U-238 does not possess the capability to directly fission.In order to enrich uranium in the 235 isotope, physical methods are required. These methods must take advantage of the extremely minute difference in weight. Throughout the course of history, a variety of methods have been utilized; however, the approach that is by a significant margin the most common option today is the utilization of a gas centrifuge.Surprisingly for such a heavy metal, uranium is capable of forming a compound that, when heated to normal conditions, behaves like a gas. This property is known as the gaseous phase transition. When UF6 is heated to temperatures higher than 133 degrees Fahrenheit or 56 degrees Celsius, it changes into a vapor or a gas rather than remaining a white solid at normal atmospheric pressure and temperatures. However, UF6 remains a white solid at normal atmospheric pressures. Because fluorine atoms are identical to one another, any variation in mass that can be observed must be attributable to the distinct isotopes of uranium.A tube that rotates at a high speed around the device's longitudinal axis constitutes a gas centrifuge's rotor. This tube is located in the center of the device. When it comes to figuring out how well a centrifuge does its job, the speed of the rotor is an extremely important factor to consider. In today's world, rotors are capable of spinning at speeds of over 60,000 revolutions per minute, and the surface of the rotor can travel at speeds that are significantly faster than the speed of sound.The spinning rotor produces powerful centrifugal forces that are analogous to a miniature gravitational field, with the obvious distinction that "up" refers to the direction toward the axis of the rotor and "down" refers to the direction toward the outer rim of the rotor. When something is placed in a centrifuge, a similar effect occurs; however, because the forces generated by the fast spinning of the high speed centrifuge are potentially one million times stronger than gravity, everything takes place on a much smaller scale. This is due to the fact that the high speed refrigerated centrifuge is spinning at a very high speed. Because of the centrifugal forces, there is not a great deal of space left over for separating the two isotopes from one another. If one end of the centrifuge is heated, warmer gas will rise at that end and flow toward the opposite end along the axis, while cooler gas will flow in along the wall to replace it. This will cause the centrifuge to operate more efficiently. This occurs due to the fact that when the gas is warmer, it moves at a faster rate. At this juncture, the gas is flowing along the wall towards one end of the centrifuge and along the center towards the other end of the apparatus.When we say that the concentration of U-238 is higher along the wall and the concentration of U-235 is higher along the center, what we mean is that, statistically speaking, each molecule containing 238 will spend more time on average along the wall than a molecule containing U-235, which will, statistically speaking, spend a relatively longer time near the center of the structure. This is why the concentration of U-238 is higher along the wall and the concentration of U-235 is higher along the center. A greater proportion of the U-235's time will be spent, on average, being propelled along with the flow along the center, and it will concentrate at the other end. The separation of uranium 235 and uranium 238 does not take place relative to the wall or the center of the centrifuge; rather, it takes place along the length of the device.