anrikningsanläggningar

Anrikningsanläggningar, or enrichment plants, are industrial facilities where the concentration of a specific fissile isotope, typically uranium-235, is increased within a uranium sample. Natural uranium contains only about 0.7% of the fissile U-235 isotope, while the majority is U-238, which is not readily fissile. For use in most nuclear reactors and for nuclear weapons, a higher concentration of U-235 is required.

The process of enrichment involves separating the isotopes of uranium based on their slight mass difference. Several technologies exist for this purpose, with gaseous diffusion and gas centrifugation being the most common. In gaseous diffusion, uranium hexafluoride gas is passed through a series of porous membranes. The lighter U-235 molecules diffuse slightly faster than the heavier U-238 molecules, leading to a gradual increase in U-235 concentration over many stages. Gas centrifugation utilizes high-speed centrifuges to spin the uranium hexafluoride gas. The heavier U-238 isotopes are forced towards the outer walls of the centrifuge, while the lighter U-235 isotopes concentrate closer to the center, allowing for separation.

The level of enrichment determines the end-use of the uranium. Low-enriched uranium (LEU), typically with a U-235 concentration of 3-5%, is used as fuel for most nuclear power reactors. Highly enriched uranium (HEU), with U-235 concentrations above 20% and often much higher, is used in some research reactors and in nuclear weapons. The operation of anrikningsanläggningar is subject to strict international regulations and safeguards due to the proliferation risks associated with enrichment technology.