The following is a rundown of Iran’s key nuclear sites. Each was a subject at diplomatic talks between the Islamic Republic and the world's six major powers.
Bushehr Nuclear Facility
The Bushehr facility contains Iran’s first nuclear power plant. Its light-water reactor was loaded with nuclear fuel in August 2010. It has an operating capacity of 1,000 megawatts. Bushehr was originally launched in 1976 under contract with a German company, but after the 1979 revolution, Washington opposed it on the grounds that weapons grade plutonium could be extracted from the reactor’s waste, allowing Iran to construct nuclear weapons. Iran says the plant is for power-generation purposes only and will be subject to International Atomic Energy Agency (IAEA) safeguards.

Natanz Fuel Enrichment Facility
This fuel enrichment facility is at the heart of Iran’s dispute with the United Nations. The National Council of Resistance of Iran, an exiled opposition group, revealed the existence of the facility in 2002. It is located just outside the city of Natanz, approximately 130 miles south of Tehran.
The site consists of two facilities:
- An above-ground pilot fuel enrichment plant (PFEP)
- A larger, underground fuel enrichment plant with the capacity to hold up to 50,000 centrifuges (FEP).

Iran has not installed new centrifuges at either of the Natanz sites since the implementation of the November 2013 Joint Plan of Action. And enrichment of uranium above five percent is no longer taking place at Natanz, according to a February 2014 U.N. report. About 160 kg of uranium enriched to 20 percent still remains at the site but some of the stockpile is being downblended or converted to uranium oxide, which could not easily be used to fuel a nuclear weapon.
Iran and the world’s six major powers reached a final nuclear deal on July 14, 2015, which stipulated that Natanz will be Iran's only enrichment facility for 15 years. During that time, enrichment will be capped at 3.67 percent, and Iran’s uranium stockpile will be limited to 300kg. The deal also limited the number of centrifuges at Natanz to 6,100 (with 5,060 operational) for 10 years.
Isfahan Uranium Conversion Facility
The historic city of Isfahan is home to several nuclear-related sites, but the most significant facility is the Isfahan Uranium Conversion Plant. Isfahan also has a fuel fabrication laboratory, a uranium chemistry laboratory and a zirconium production plant. The conversion plant has been operational since 2006, and converts uranium yellowcake into uranium hexafluoride (UF6) for Iran's enrichment facilities. The facility can also produce uranium metal and oxides for fuel and other purposes.
Tehran Nuclear Research Center

Arak Heavy Water Plant and Reactor
The Arak nuclear facility includes a heavy water production plant, which has been operational since 2006, and a 40-megawatt heavy water reactor still under construction. The National Council of Resistance of Iran, an exiled opposition group, also revealed the existence of this facility in 2002.

In December 2013, Iran provided the IAEA with information and access to the plant. Approximately 100 tons of reactor-grade heavy water have been produced at Arak since 2006.
The final nuclear deal requires Iran to redesign the Arak reactor so it will not produce weapons-grade plutonium. Iran also agreed to refrain from building any new heavy water reactors for 15 years.
Qom Uranium Enrichment Facility (Fordo)

The facility’s revelation prompted concern that Iran intended to construct a potential breakout facility where it could make weapon-grade uranium for a nuclear bomb. Iran told the IAEA that the plant was intended to enrich uranium only to 5 percent, which is not enough for a nuclear weapon. The plant is believed to have room for 3,000 centrifuges for uranium enrichment.
The final nuclear deal prohibits Iran from conducting enrichment or research and development at Fordo for 15 years.
Parchin
Parchin is a military complex about 19 miles southeast of Tehran. The IAEA suspects Iran may have conducted experiments related to nuclear weapons production. U.N. inspectors visited the site twice in 2005 but did not find anything suspicious. But the IAEA later received additional evidence about alleged experiments. “We didn’t have enough information [back then],” IAEA chief Yukiya Amano said in 2012. “Extensive activities have taken place” at Parchin that have “seriously undermined” the IAEA’s ability to investigate possible military dimensions of Iran’s program, according to a February 2014 report.
Iran apparently undertook cleanup activities, according to satellite imagery analyzed by the Institute for Science and International Security. The IAEA noted that satellite imagery revealed “possible building material and debris” at Parchin in 2014.
On July 14, 2015, International Atomic Energy Agency (IAEA) chief Yukiya Amano and Head of the Atomic Energy Organization of Iran Ali Akbar Salehi agreed on a roadmap to resolve outstanding issues, including the possible military dimensions of Iran’s nuclear program. The roadmap includes a “separate arrangement regarding the issue of Parchin.” The IAEA plans to complete a report by December 2015, which will precede the sanctions relief specified in the final nuclear deal.
Gchine Mine and Mill
The Gchine mine is located in southern Iran in Bandar Abbas. The associated mill is located at the same site. According to the IAEA, it began production in 2004 and has an estimated production capacity of 21 tons of uranium per year. The IAEA has questioned the mine’s ownership and relationship to Iran’s military. In January 2014, Iran provided the IAEA with managed access to the mine.
July 14 Update: Iran released the most detailed report to date explaining its practical needs for its nuclear program. It was posted on the quasi-official website NuclearEnergy.ir.
Photo credits: NuclearEnergy.ir, Natanz via Iranian President's Office and The New York Times