Process of Uranium Ore in Australia
Process of Uranium Ore in Australia
currently American nuclear power plants store the spent fuel in spent fuel pools without reprocessing. Why? Mainly because reprocessing is more expensive than making new fuel from uranium ore.
.Mining. The first step in the nuclear fuel cycle is mining the uranium ore. Workers mine uranium ore much as coal miners mine coal-in deep underground mines or in open-pit surface mines. A ton of uranium ore in the United States typically contains three to four pounds of uranium.
Milling. After it has been mined uranium ore is crushed. The crushed ore is usually poured into an acid, which dissolves the uranium, but not the rest of the crushed rock. The acid solution is drained off and dried, leaving a yellow powder called “yellowcake,” consisting mostly of uranium. This process of removing uranium from the ore is called uranium milling.
Conversion. The next step in the cycle is the conversion of the yellowcake into a gas called uranium hexafluoride, or UF6. The uranium hexafluoride is then shipped to a gaseous diffusion plant for enrichment.
Enrichment. Because less than one percent of uranium ore contains uranium-235, the form used for energy production, uranium must be treated to increase the concentration of uranium-235. This treatment process–called uranium enrichment–increases the percentage of uranium-235 from one to three percent. It typically takes place at a gaseous diffusion plant where the uranium hexafluoride is pumped through filters that contain extremely tiny holes. Because uranium-235 has three fewer neutrons and is one percent lighter than uranium-238, it moves through the holes more easily than uranium-238. This method increases the percentage of uranium-235 as the gas passes through thousands of filters.
Fuel Fabrication. The enriched uranium is then taken to a fuel fabrication plant where it is prepared for the nuclear reactor. Here, the uranium is made into a solid ceramic material and formed into small barrel-shaped pellets. These ceramic fuel pellets can withstand very high temperatures, just like the ceramic tiles on the space shuttle. Fuel pellets are about the size of your fingertip, yet each one can produce as much energy as 120 gallons of oil. The pellets are then stacked and sealed in 12-foot metal tubes called fuel rods. Finally, the fuel rods are bundled into groups called fuel assemblies.
Nuclear Reactor. The uranium fuel is now ready for use in a nuclear reactor. Fissioning takes place in the reactor core. Surrounding the core of the reactor is a shell called the reactor pressure vessel. To prevent heat or radiation leaks, the reactor core and the vessel are housed in an air-tight containment building made of steel and concrete several feet thick.
The reactor core houses approximately 200 fuel assemblies. Spaced between the fuel assemblies are movable control rods. Control rods absorb neutrons and slow down the nuclear chain reaction. They are called control rods because they help control the fissioning process. Water also flows up through