IRAN’S NUKESWhy the U.S. Bombed a Bunch of Metal Tubes − a Nuclear Engineer Explains the Importance of Centrifuges to Iranian Efforts to Build Nuclear Weapons
It’s not clear what the U.S. attack has accomplished, but destroying the facilities targeted in the attack and hindering Iran’s ability to continue enriching uranium might be a way to slow Iran’s move toward producing nuclear weapons. But history shows that a more reliable means of preventing Iran from achieving its nuclear aims would be for diplomacy and cooperation to prevail.
When U.S. forces attacked Iran’s nuclear facilities on June 21, 2025, the main target was metal tubes in laboratories deep underground. The tubes are centrifuges that produce highly enriched uranium needed to build nuclear weapons.
Inside of a centrifuge, a rotor spins in the range of 50,000 to 100,000 revolutions per minute, 10 times faster than a Corvette engine’s crankshaft. High speeds are needed to separate lighter uranium-235 from heavier uranium-238 for further collection and processing. Producing this level of force means the rotor itself must be well balanced and strong and rely on high-speed magnetic bearings to reduce friction.
Over the years, Iran has produced thousands of centrifuges. They work together to enrich uranium to dangerous levels – close to weapons-grade uranium. Most of them are deployed in three enrichment sites: Natanz, the country’s main enrichment facility, Fordow and Isfahan. Inside of these facilities, the centrifuges are arranged into cascades – series of machines connected to each other. This way, each machine yields slightly more enriched uranium, feeding the gas produced into its neighbor to maximize production efficiency.
As a nuclear engineer who works on nuclear nonproliferation, I track centrifuge technology, including the Iranian enrichment facilities targeted by the U.S. and Israel. A typical cascade deployed in Iran is composed of 164 centrifuges, working in series to produce enriched uranium. The Natanz facility was designed to hold over 50,000 centrifuges.
Iran’s early intentions to field centrifuges on a very large scale were clear. At the peak of the program in the early 2010s it deployed over 19,000 units. Iran later scaled down the number of its centrifuges in part due to international agreements such as the since scrapped Joint Comprehensive Plan of Action signed in 2015.
Legacy of Enrichment
Iran has a long history of enriching uranium.
In the late 1990s, it acquired a Pakistani centrifuge design known as P-1. The blueprints and some components were supplied via the A.Q. Khan black market network – the mastermind of the Pakistani program and a serious source of nuclear proliferation globally. Today, the P-1 design is known as IR-1. IR-1 centrifuges use aluminum and a high-strength alloy, known as maraging steel.
