Fordo refers to the Fordow Fuel Enrichment Plant (FFEP), a heavily fortified underground uranium enrichment facility in Iran, making it a critical international institution in the context of nuclear non-proliferation. Construction of the facility began around 2006 or 2007 on a former military base of the Islamic Revolutionary Guard Corps (IRGC) near the city of Qom. Its existence was kept secret until it was revealed by the leaders of the United States, the United Kingdom, and France in September 2009, after which Iran disclosed it to the International Atomic Energy Agency (IAEA).
The facility was built deep under a mountain, designed to be resistant to aerial attacks, and was intended to house approximately 3,000 centrifuges in two enrichment halls. Uranium enrichment operations began in December 2011, initially producing uranium enriched to 20% purity. Fordo is intrinsically connected to the Joint Comprehensive Plan of Action (JCPOA), the 2015 Iran nuclear deal, which required the facility to cease all uranium enrichment for 15 years and be converted into a research center for stable isotope production.
Following the US withdrawal from the JCPOA in 2018, Iran resumed enrichment activities at Fordo in November 2019, violating the agreement. This marked a significant change, as Iran has since escalated its activities, beginning production of uranium enriched to 60% purity at Fordo in November 2022. Furthermore, the IAEA reported finding uranium enriched to 83.7% purity at the facility in March 2023, a level close to weapons-grade. Due to its hardened structure, Fordo remains a key point of geopolitical tension, with its potential destruction requiring powerful munitions like the US GBU-57 "bunker buster" bombs.