About uranium
Uranium is the main element used in nuclear reactors. Find out about the environmental requirements we impose on our suppliers, the mining process and the properties of uranium.
What is uranium?
Uranium is a metallic element that is slightly radioactive - about the same level as one of our most common rocks, granite. Uranium is the most abundant radioactive element in the Earth's crust. There are three isotopes of natural uranium, all with half-lives of millions of years. Of the three isotopes, uranium-235 has the special property that when it is split, by free neutrons, large amounts of energy are released. This is the process used to produce energy in a nuclear power plant.
How is uranium mined?
There are three main methods used in uranium mining. The most common is mining, followed by open-pit mining and underground leaching. A small amount of uranium is obtained as a by-product of the production of other minerals, mainly from mines.
The largest producers of uranium in the world today are Canada and Australia.
The fuel chain
Natural uranium is too low in the fissile isotope uranium-235 to be used directly as fuel in a nuclear reactor. Therefore, the minable uranium ore must be processed in a number of steps.
- The ore is crushed and treated with dilute sulphuric acid to dissolve the uranium from the ore. The uranium is then precipitated from the acid solution in the form of uranium oxide (chemically known as U3O8). In this form, the uranium is sold from the mine.
- In the next step, the uranium oxide is converted into uranium hexafluoride, UF6, in which the natural uranium is enriched to increase the uranium-235 content from 0.71% to between three and five percent.
- Finally, the gas is converted into uranium dioxide, UO2, which can be pressed and sintered into a ceramic material. In a fuel fabrication plant, the uranium dioxide is pressed into finger-thick cuttings with a density of about 10 g/cm³. The cuttings are inserted into cladding tubes, usually consisting of an alloy that is 90% zirconium.
Where does OKG's uranium come from?
URENCO is the supplier of OKG’s annual requirement for enriched uranium.
OKG’s contract with URENCO includes a list of countries from which OKG accepts uranium deliveries, such as the United States, Australia, Canada, Kazakhstan, and Uzbekistan.
How does OKG control its fuel chain?
The environmental requirements that OKG imposes on uranium suppliers are extensive. We systematically monitor suppliers with regard to climate and environmental impact through regular reviews. These reviews assess, among other things, how suppliers work with environmental management, emissions, resource use, and regulatory compliance.