1957: Iran and the United States sign a civil nuclear cooperation agreement that provides for technical assistance and the lease of several kilograms of enriched uranium. It also calls for both countries to cooperate in research on the peaceful uses of nuclear energy.
1967: Startup of the U.S.-supplied thermal research reactor at the Tehran Nuclear Research Center.
1968: Iran signs the Nuclear Non-Proliferation Treaty (NPT). The treaty is ratified by Iran in 1970.
1974: The shah establishes the Atomic Energy Agency of Iran and announces that Iran will produce 23,000 megawatts of nuclear power by the end of the century. Iran contracts with a German company to build a power reactor at Bushehr.
1975: Iran and the United States sign a trade agreement, which calls for the purchase of eight reactors.
1976: Iran purchases stakes in Eurodif 's Tricastin uranium enrichment plant in France and the RTZ uranium mine in Rossing, Namibia. South Africa agrees to sell Iran $700 million of yellowcake. In return, Iran agrees to finance an enrichment plant in South Africa.
1977: Iran contracts with a French company to build two reactors at Darkhovin. Following the Islamic revolution, Iran cancels the contract in 1979.
1979: Following the takeover of its embassy in Tehran, the United States cuts off all nuclear agreements with Iran.
1984: Iran opens a nuclear research center at Isfahan.
1985: Iran begins its gas centrifuge program during the war with Iraq, in which both use chemical weapons against each other. Iran claims the only purpose of its centrifuge program is to make fuel for the German-supplied power reactor under construction at Bushehr. The claim is dubious; by 1985, Germany had suspended all work at the reactor, which was heavily damaged during the war, and did not resume construction at war's end. The decision is widely perceived as being part of an effort to make highly enriched uranium for nuclear weapons.
1987: Iran announces plans to set up a yellowcake plant in Yazd province and signs a nuclear cooperation agreement with Pakistan.
1990: Iran signs nuclear cooperation agreements with China and the Soviet Union.
1992: International Atomic Energy Agency (IAEA) inspections in Iran find no evidence of illegal nuclear activity. A followup visit 1 year later also detects no evidence.
1994: Iran and China announce an agreement to build a 300-megawatt reactor near Tehran.
1995: Russia signs a contract to finish the Bushehr reactor, and Iran accelerates its gas centrifuge program. While no one has produced compelling evidence that Iran has a nuclear weapons program, the timing, scope, and long secrecy of the program lead many nations to conclude that Iran either had or has a nuclear weapons program.
1997: China agrees to halt nuclear assistance to Iran.
2002: The National Council of Resistance in Iran, an Iraq-based opposition group, reveals the existence of the previously unknown uranium--enrichment facility at Natanz and a heavy--water production plant at Arak.
2003: International focus shifts to Iran's secret nuclear programs and its violations of its IAEA safeguards agreement and the NPT. In October, the foreign ministers of the United Kingdom, France, and Germany (known as the European Union [EU]-3) and Hassan Rohani, secretary of the powerful Supreme National Security Council, reach agreement requiring Iran to cooperate fully with the IAEA to resolve outstanding issues, voluntarily suspend its activities related to uranium enrichment and reprocessing, and sign and start the ratification process of the IAEA advanced safeguards protocol. (1) In return, the EU-3 foreign ministers promise that their governments will recognize Iran's right to the peaceful uses of nuclear energy in accordance with the NPT, and express their willingness to help resolve the situation with the IAEA board of governors and promote regional security and stability. …