Northeast of the Shiite holy city of Qom lies Iran's Fordow facility – the Islamic Republic's second uranium enrichment site and its most heavily fortified. Unlike the larger and better-known Natanz plant, Fordow is a smaller facility but is buried deep within a mountain, 80 to 90 meters underground, making it virtually impervious to conventional airstrikes.
Why Fordow matters – and how it differs from Natanz
To grasp Fordow's critical importance, it helps to compare it with Natanz. The latter is a sprawling complex housing over 19,000 centrifuges, and according to the Institute for Science and International Security (ISIS), could potentially accommodate up to 50,000. However, Natanz has a key vulnerability – it is buried just eight meters below ground. According to the International Atomic Energy Agency, its surface buildings were completely destroyed in a previous attack. While the underground halls remained intact, the damage to its electrical systems suggests possible harm to the centrifuges.
Fordow, however, is a different story. With about 3,000 centrifuges spread across two halls, it is much smaller – but it is buried 80 to 90 meters underground, inside solid rock. While Natanz enriches uranium to low levels (3–5%), Fordow is Iran's main site for higher-level enrichment – up to 60%, and traces of uranium enriched to 83.7% were recently detected there, dangerously close to the 90% level required for nuclear weapons. In essence, Fordow serves as Iran's "insurance policy" for its nuclear program, a secure site where the regime could rapidly move to weapons-grade enrichment if it decides to pursue a bomb.
Enrichment is the process of increasing the concentration of fissile material – a specific isotope of uranium found only in small quantities in mined ore. High-speed centrifuges separate heavier particles from lighter ones, and the resulting gas is then converted back into metal. For weapons production, the fissile material is shaped into a sphere and combined with a triggering mechanism to form a nuclear bomb.
Satellite imagery underscores why Fordow poses such a major challenge to Israel and others concerned with Iran's nuclear ambitions. Winding roads lead directly into tunnels dug into the mountain, giving access to the underground centrifuge halls. Most of the facility – including thousands of centrifuges enriching uranium to near-weapons grade – is hidden deep within rock, shielded in a way that makes it virtually invulnerable to standard aerial assaults.
A secret revealed
Originally a missile base run by the Islamic Revolutionary Guard Corps, Fordow's conversion into a nuclear enrichment site began around 2006–2007, according to Western intelligence. For years, its existence was kept secret until the US, UK, and France exposed it in September 2009 after it was detected by intelligence services. Iran was forced to acknowledge the site to the International Atomic Energy Agency, claiming it was for civilian purposes.
But nuclear archive documents seized by Israel in 2018 told a different story: Fordow – referred to as "Project Al-Ghadir" – was planned as part of the "Amad Project," Iran's covert nuclear weapons development program.
