Jul 17, 2022
A cascade of gas centrifuges at a U.S. enrichment plant in Piketon, Ohio, in 1984. Iran is using similar technology to enrich uranium. U.S. Department of Energy.Iran’s nuclear program was a major topic in President Joe Biden’s July 13-16, 2022, trip to the Middle East. The most challenging part of producing nuclear weapons is making the material that fuels them, and Iran is known to have produced uranium that is near-weapons grade.
Enrichment is the process of separating out and increasing the concentration of U-235 to higher levels above natural uranium. Generally speaking, lower levels of enriched uranium, such as uranium with 5% U-235, are commonly used for nuclear reactor fuel. Higher levels of enrichment, such as 90% U-235, are most desirable for nuclear weapons.
A gas centrifuge separates uranium-235 atoms, which can sustain a nuclear chain reaction, from much more abundant atoms of uranium-238, which cannot. As the centrifuge rotates at high speed, uranium hexafluoride gas is pumped into it. The heavier U-238 molecules move toward the outer edge, and the lighter U-235 molecules move toward the center. The ‘product stream’ of gas enriched in U-235 is pumped through many more centrifuges, increasing the concentration of U-235 at each stage.
The higher the level of enrichment, the smaller the amount of nuclear material necessary to produce a nuclear weapon.identifies 25 kilograms of 90% enriched uranium as a “significant quantity” necessary for a simple nuclear weapon. But larger amounts of lower-enriched uranium can also work.