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.
Source » isisnucleariran