Key sites of Iran's nuclear program:
— BUSHEHR: Iran's first energy-producing nuclear reactor, which began receiving nuclear fuel on Saturday. The Russian-built facility is expected to begin producing power in two months.
Washington for years pushed Russia to stop its help on the Bushehr plant, fearing that spent fuel from the reactor could be used to develop a weapon. But American opposition eased when Iran agreed in 2005 to return all nuclear material to Russia to ensure it can't be reprocessed.
Bushehr operations are not mentioned in U.N. or other sanctions.
— PLANNED: Iran says it has drawn up plans for one energy-producing reactor — smaller than Bushehr — in Darkhovin in the southwestern Khuzestan province. There is no clear timetable for the proposed Iranian-built plant. Officials say others could be built in the coming decades.
— RESEARCH: Two small reactors mainly involved in agricultural studies; a larger research reactor is under construction in Arak in western Iran.
— NATANZ: Iran's main uranium enrichment facility and the centerpiece of the nuclear dispute with the West. Iran says it only seeks to produce lower-enriched fuel for research and power reactors, but the United States and others worry Iran could eventually push toward weapons-grade material.
The facility, about 160 miles (260 kilometers) southeast of Tehran, is largely built underground and is surrounded by anti-aircraft batteries. Uranium enrichment began in 2006.
— FORDO: Another uranium enrichment facility identified by Western intelligence agencies in September 2009. The labs, near the holy city of Qom south of Tehran, are still under construction inside former ammunition depots carved into a mountainside. The area is heavily protected by the Revolutionary Guard.
U.N. nuclear inspectors toured the previously secret site in October 2009.
— ISFAHAN: Iran's Uranium Conversion Facility, which reprocesses uranium concentrate known as yellowcake into a gas that is fed into centrifuges for enrichment at Natanz.
— SAGHAND: Iran's main uranium mine in the central province of Yazd. It is the country's main source of uranium ore.