Uranium Mining and Fuel Conversion

 

Uranium Extraction Process

Uranium, in contrast to gold and other rare minerals, is relatively common and can be found in varying quantities in rocks at and beneath the earth's surface, as well as in seawater. However, it is known to exist in deposits of sufficient concentrations to be economically extracted only in limited locations where the geologic setting provides the required hosting conditions. Where these deposits of uranium exist, it is generally extracted by one of three methods:

- Open-cut (or open-pit), in which surface overburden is removed to allow access to high concentration uranium ore. The ore is then sent to a mill, where it is crushed and ground and the uranium particles are separated;

- Underground, where shafts and tunnels are dug into the earth to reach the uranium ore-body. As with open-cut, the ore is then sent to a mill for crushing, grinding and separation; and

- In-situ recovery (ISR), a process whereby uranium-containing fluid is extracted from underground aquifers through injector and extractor wells between the surface and the uranium ore body. A uranium-enriched liquid is then sent to a processing plant to separate the uranium, before being dried and packaged. In each of these extraction methods, the mills (or processing plants, in the case of ISR mines) generally produce a fine powder (also called yellowcake) in the form of uranium oxide (U3O8). Nuclear Fuel Conversion Process After being converted into yellowcake, uranium is generally packaged into steel drums and shipped overseas where it is converted from uranium oxide into fuel for electricity-generating nuclear power plants. The steps in this process are:

- Conversion and enrichment - converting yellowcake into uranium hexafluoride and then creating a product enriched in uranium-235 through gaseous diffusion or a centrifuge,

- Fuel fabrication - creating fuel pellets from enriched uranium, and

- Power generation - creating a fission reaction within a nuclear reactor from the uranium fuel pellets to create electricity.