Uranium enrichment is a critical process that increases the concentration of the fissionable isotope uranium-235 in natural uranium. Natural uranium consists of about 99.3% uranium-238 and 0.7% uranium-235. For use in nuclear reactors or weapons, the proportion of uranium-235 must be raised to between 3% and 5% for reactor fuel, or over 90% for weapons-grade material.
The most common enrichment method is gas centrifugation. Uranium is first converted into uranium hexafluoride gas, which is then spun at high speeds in centrifuges. The heavier uranium-238 isotopes are forced outward, while the lighter uranium-235 isotopes collect near the center. This process is repeated in cascades of thousands of centrifuges to gradually increase the enrichment level.
Another technique is laser enrichment, which uses tuned lasers to selectively ionize uranium-235 atoms, allowing them to be separated magnetically. This method is more energy-efficient but technically challenging.
Enrichment facilities are tightly regulated by international bodies like the International Atomic Energy Agency (IAEA) to prevent proliferation. The process remains a cornerstone of nuclear energy and non-proliferation efforts worldwide.