Uranium Enrichment

Fordow Fuel Enrichment Plant (FFEP)

Iran began constructing the Fordow uranium enrichment facility in secret as early as 2006.  It was publicly revealed by U.S. President Barack Obama, French President Nicolas Sarkozy, and British Prime Minister Gordon Brown in September 2009, shortly after these nations presented evidence of the facility to the International Atomic Energy Agency (IAEA).  The facility appears to be a repurposed tunnel complex, with the main enrichment halls buried within a mountain in order to harden the facility against a potential military strike.  Satellite imagery dates the construction of the facility to a period between June 2006 and July 2007, while Iran has told the IAEA that it began to build the facility during the second half of 2007.  After the disclosure of the plant’s existence, Iran downplayed its role in its nuclear program, moving slowly to install the planned number of centrifuges at the site.  In mid-2011, it announced it would install advanced centrifuges at the FFEP rather than IR-1 centrifuges. The facility is designed to hold approximately 3,000 centrifuges. It never installed advanced centrifuges in the facility, but instead deployed the IR-1 model.

The Fordow site has two enrichment halls, Units 1 and 2, each designed to hold 8 cascades of 174 centrifuges per cascade. Iran fully outfitted the facility in late 2012 – early 2013.

On June 8, 2011, Iran announced that it planned to move its production of 19.75% enriched uranium from the Natanz Pilot Fuel Enrichment Plant (PFEP) to the FFEP, and that it would enrich 3.5% low-enriched uranium produced at the Fuel Enrichment Plant at Natanz. Since February 2013, Iran has produced 19.75 percent enriched uranium at the FFEP using sets of tandem cascades to enrich uranium to 19.75 percent and strip the tails to natural uranium (0.711 percent). Iran claims that the 19.75 percent enriched uranium produced in this facility will be used to produce medical isotopes in the Tehran Research Reactor.

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The Natanz Fuel Enrichment complex is the primary site of Iran’s gas centrifuge program. It contains two primary facilities:  the Pilot Fuel Enrichment Plant (PFEP) and the Fuel Enrichment Plant (FEP).  It also houses a centrifuge assembly area.  The two primary facilities, as well as other buildings at the Natanz site, can be seen in satellite imagery below.

On March 30, 2005, then President Mohammad Khatami toured the Natanz site accompanied by the media.  This tour produced the first publicly available ground images of Natanz.  A subsequent visit by President Mahmoud Ahmadinejad in 2008 led to many images of the complex and centrifuges in the pilot plant. 

The Natanz facility was first publicly identified by the National Council for Resistance of Iran (NCRI) in August 2002.  At that time, NCRI identified the facility as a nuclear fuel fabrication plant.  In December 2002, ISIS released satellite photos of the facility for the first time and correctly identified the site as a gas centrifuge enrichment facility.

Natanz Fuel Enrichment Plant

The Natanz Fuel Enrichment Plant (FEP) is Iran’s largest gas centrifuge uranium enrichment facility. It consists of three large underground buildings, two of which are designed to be cascade halls to hold 50,000 centrifuges.  The buildings started as 70 foot deep holes, and satellite imagery showed the construction of thick concrete walls. The FEP began operating in February 2007, and construction on centrifuge cascades is ongoing. The FEP ostensibly exists to produce enriched uranium for light water reactors in Iran, including the Bushehr facility and others that Iran has not yet built.

Iran uses the FEP to produce 3.5 percent low-enriched uranium (LEU) for its nuclear program. Until early 2013, it installed only IR-1 centrifuges in single 174- and 164- machine cascades. Iran announced to the IAEA on January 23, 2013 that it intended to install IR-2m advanced centrifuges at the FEP.

Natanz Pilot Fuel Enrichment Plant

The Pilot Fuel Enrichment Plant (PFEP) is Iran’s centrifuge research and development facility which uses uranium hexafluoride.  Iran has other facilities, mostly unknown publicly, which conduct important tests of centrifuges without introducing uranium hexafluoride.  More is known about the PFEP than other centrifuge manufacturing facilities because its use of uranium hexafluoride requires inspections by the IAEA, which then reports publicly on activities there.

In 2002, Iran moved gas centrifuge research, development, and assembly operations to this facility from Kalaye Electric, its then secret site near Tehran. The PFEP is an above-ground building at the Natanz Fuel Enrichment complex. 

Iran tests centrifuges of various models, including its deployed IR-1 and IR-2m, but also more advanced designs, in single machine, small cascades, and production-scale cascades at the PFEP. Typically, in the test cascades, Iran recombines the product and tails from these cascades, so no enriched uranium is produced.

Since February 2010, Iran has produced 19.75 percent enriched uranium in a set of two, 164-machine IR-1 cascades oriented in tandem, ostensibly for the Tehran Research Reactor (TRR).  One of these cascades enriches from 3.5 percent LEU to almost 20 percent low enriched uranium (LEU), while the second one takes the tails from the first and outputs roughly 10 percent LEU and a tails of natural uranium.  The ten percent material is fed into the first cascade in addition to 3.5 percent LEU.  This process allows Iran to more efficiently use its 3.5 percent LEU stock.

For more information check: Related Reports