Iran nuclear program: 5 key sites

Iran’s nuclear program is the subject of constant scrutiny by the international community, particularly the United States and Israel. Here are five of Iran’s most important nuclear sites.

1.Bushehr nuclear power plant

This file photo made Friday, Aug. 20, 2010, shows the Bushehr nuclear power plant, outside the southern city of Bushehr, Iran. (Vahid Salemi/AP/File)

The Bushehr nuclear power plant, perhaps the most well-known nuclear site in Iran, made headlines in 2010 as a suspected target of the computer virus Stuxnet. Iranian nuclear officials denied that any damage was done by a cyberattack, but soon after they announced delays in the reactor’s launch.

Bushehr is central to Iran's nuclear power program and, in September 2011, became the country's first nuclear reactor to come online. Germany originally began work on a reactor at Bushehr in 1975, but abandoned it after the 1979 Islamic Revolution. In the 1990s, Iran's nuclear partnership with Russia revived the Bushehr project, but its completion was plagued by delays, financial troubles, and pressure from the West.

The plant, located in southwestern Iran on the Persian Gulf, once elicited widespread concern, especially in the US and Israel. As a light-water nuclear reactor that uses low-enriched uranium to produce electricity, its spent fuel includes plutonium that could be reprocessed to produce nuclear weapons. However, with Russia supplying the nuclear fuel and reprocessing spent fuel in Russia, most experts no longer consider Bushehr a proliferation risk.

Arak heavy water reactor

According to the Institute for Science and International Security (ISIS), Iran began work on the Arak heavy-water reactor, located in central Iran, in the 1990s. It was not acknowledged by Iran, however, until its existence was revealed in 2002 by the Iranian opposition group Mojahedin-e Khalq (MEK, a.k.a. MKO), based on data widely believed to have been supplied by Israel.

The disclosure – along with the that of an unknown underground centrifuge facility at Natanz – spurred speculation that Iran's nuclear program was not purely for civilian purposes, as Tehran claims. Following the disclosure, the US accused Iran of pursuing nuclear weapons in 2004.

The United Nations ordered Iran to halt work on heavy-water projects, including the construction of the reactor, citing Iran’s “lack of cooperation” with IAEA. The latest IAEA report states that the Arak reactor is scheduled to begin operation at the end of 2013.

Iran has not given IAEA inspectors access to the Arak reactor, despite requests, nor access to water from the reactor in order to take samples. Inspectors have instead had to rely on less effective satellite imagery.

Natanz uranium fuel enrichment plant

In this Tuesday, April 8, 2008, photo released by the Iranian President's Office, Iranian President Mahmoud Ahmadinejad, center, visits the Natanz Uranium Enrichment Facility some 200 miles south of Tehran, Iran. (Iranian President's Office/AP/File)

The existence of the Natanz plant, Iran’s key uranium enrichment site, was also disclosed in 2002 by the MEK. Located in central Iran, it is a key uranium enrichment site and is now the primary site for Iran’s centrifuge program. It holds about 8,000 centrifuges for making nuclear fuel in its underground facility, although a 2011 IAEA report states that about 1,000 centrifuges were damaged by the Stuxnet computer virus. Later reports indicated that those centrifuges were quickly replaced.

The Natanz site is one of the most controversial sites in the country. Iran claims it aims only to produce nuclear power peacefully, and the low-enriched uranium refined to 3.5 percent purity at Natanz is meant to fuel nuclear reactors. But when enriched to far higher levels, such as 90 percent, the material can be used to make a nuclear weapon. So far, Iran has shown it can enrich to almost 20 percent and says it is stopping there.

The UN ordered a halt to uranium enrichment activities at Natanz at the same time it ordered a halt on Arak’s operations, but Iran has not complied.

Fordow fuel enrichment plant

The existence of the Fordow plant beneath a mountain near the holy city of Qom was only revealed in September 2009, prompted by its imminent disclosure by Western countries. Iran had already been conducting years of work on the facility, slated to hold roughly 3,000 centrifuges, and at the time it was in an “advanced state of construction,” according to the IAEA, which was first allowed inside the facility in October 2009.

Iran said it built the Fordow plant in response to threats against its facilities in Natanz. The belated disclosure about Fordow's existence severely damaged Iran's credibility with the IAEA.

In 2011, Iran told the IAEA that it will use Fordow to continue to enrich uranium to 20 percent, a process which the UN told Tehran to halt. Centrifuge installation there has begun, as has the transfer of low-enriched uranium for further refining. In August 2012, the IAEA reported that the number of centrifuges at Fordow had more than doubled to 2,140, up from 1,064 in May. But the IAEA said the additional centrifuges were not yet operational.

Tehran Research Reactor

The Tehran Research Reactor is a light-water nuclear reactor given to Iran by the US in 1967, along with weapon-grade uranium fuel, when Iran was ruled by the pro-West Shah. After the Islamic Revolution in 1979, with Iran no longer able to procure the necessary grade fuel from either the US or Europe, the reactor was modified to use fuel of just below 20 percent enriched uranium.

Iran ran out of fuel shortly in 2011. When it made a request to acquire more, the IAEA crafted a fuel-swap deal in October 2009, in which Iran would hand over the bulk of its homemade low-enriched uranium to be converted by Russia and France into the 20 percent fuel needed. Iran initially agreed, then rejected the deal, prompting several other plans to date that have all failed.

Iran has since stated it would make the fuel itself, despite technical hurdles that prevent all but a few countries in the world today from manufacturing such fuel. Iran nevertheless began enriching uranium to 19.75 percent for the fuel – taking one big step closer, technically, to bomb-grade levels.

In Feb. 2012, Iran announced that for the first time it was loading domestically made nuclear fuel rods into the Tehran Research Reactor.