1957 – The United States signs a civil nuclear cooperation agreement with Iran.
1958 – Iran joins the IAEA.
1967 – The Tehran Nuclear Research Center, which includes a small reactor supplied by the United States, opens.
1968 – Iran signs the Nuclear Non-Proliferation Treaty.
Mid-1970s – With US backing, Iran begins developing a nuclear power program.
1979 – Iran’s Islamic revolution ends Western involvement in the country’s nuclear program.
December 1984 – With the aid of China, Iran opens a nuclear research center in Isfahan.
February 23, 1998 – The United States announces concerns that Iran’s nuclear energy program could lead to the development of nuclear weapons.
June 19, 2003 – The IAEA issues a report saying that Iran appeared to be in compliance with the Non-Proliferation Treaty, but that it needed to be more open about its activities.
August 2003 – The IAEA announces that its inspectors in Iran have found traces of highly enriched uranium at the Natanz uranium enrichment plant. Iran claims the amounts are contamination from equipment bought from other countries. Iran agrees to sign a protocol of the Nuclear Non-Proliferation treaty that allows for unannounced visits to their nuclear facilities and signs it on December 18, 2003.
October 2003 – The Foreign Ministers of Britain, France and Germany visit Tehran, and all parties agree upon measures Iran will take to settle all outstanding issues with the IAEA. Under obligation to the IAEA, Iran releases a dossier on its nuclear activities. However, the report does not contain information on where Iran acquired components for centrifuges used to enrich uranium, a fact the IAEA considers important in determining whether the uranium is to be enriched for weapons.
February 2004 – A.Q. Khan, “father” of Pakistan’s nuclear weapons program, admits to having provided Iran and other countries with uranium-enrichment equipment.
June 1, 2004 – The IAEA states they have found traces of uranium that exceed the amount used for general energy production. Iran admits that it is importing parts for advanced centrifuges that can be used to enrich uranium, but is using the parts to generate electricity.
July 31, 2004 – Iran states that it has resumed production on centrifuge parts used for enriching uranium, but not enrichment activities.
August 8, 2005 – Iran restarts uranium conversion, a step on the way to enrichment, at a nuclear facility, saying it is for peaceful purposes only, and flatly rejects a European offer aimed at ensuring the nation does not seek nuclear weapons.
August 9, 2005 – Iran removes the IAEA seals from its Isfahan nuclear processing facility, opening the uranium conversion plant for full operation. IAEA spokesman Mark Gwozdecky states that the plant “is fully monitored by the IAEA” and “is not a uranium enrichment plant.”
September 11, 2005 – Iran’s new foreign minister, Manouchehr Mottaki, says the country won’t suspend activities at its Isfahan uranium conversion facility and it plans to seek bids for the construction of two more nuclear plants.
January 10, 2006 – Iran resumes research at its Natanz uranium enrichment plant, arguing that doing so is within the terms of an agreement with the IAEA.
January 13, 2006 – Mottaki states that if Iran is referred, its government under law will be forced to stop some of its cooperation with the IAEA, including random inspections.
April 11, 2006 – Hashemi Rafsanjani, Iran’s former president, states that Iran has increased the number of functioning centrifuges in its nuclear facilities in Natanz and has produced enriched uranium from them.
August 31, 2006 – The IAEA issues a report on Iran saying the Islamic republic “has not suspended its enrichment activities” despite this day’s deadline to do so. Iran can possibly face economic sanctions.
December 23, 2006 – The UN Security Council votes unanimously to impose sanctions against Iran for failing to suspend its nuclear program.
February 22, 2007 – The IAEA issues a statement saying that Iran has not complied with the UN Security Council’s call for a freeze of all nuclear activity. Instead, Iran has expanded its uranium enrichment program.
May 23, 2007 – The IAEA delivers its report to the United Nations on Iran’s nuclear activities. The report states that not only has Iran failed to end its uranium enrichment program but has in fact expanded its activity.
June 21, 2007 – Iran’s Interior Minister Mostapha PourMohamedi claims, “Now we have 3,000 centrifuges and have in our warehouses 100 kilograms of enriched uranium.” …”We also have more than 150 tons of raw materials for producing uranium gas.”
February 20, 2009 – The Institute for Science and International Security reports that Iranian scientists have reached “nuclear weapons breakout capability.” The report concludes Iran does not yet have a nuclear weapon but does have enough low-enriched uranium for a single nuclear weapon. An official at the IAEA cautions about drawing such conclusions. The IAEA says Iran’s stock of low-enriched uranium would have to be turned into highly enriched uranium to become weapons-grade material.
February 25, 2009 – Iran runs tests at its Bushehr nuclear power plant using “dummy” fuel rods loaded with lead in place of enriched uranium to simulate nuclear fuel. A news release distributed to reporters at the scene states the test measured the “pressure, temperature and flow rate” of the facility to make sure they were at appropriate levels. Officials say the next test will use enriched uranium, but it’s not clear when the test will be held or when the facility will be fully operational.
September 21, 2009 – In a letter to the IAEA, Iran reveals the existence of a second nuclear facility. It is located underground at a military base, near the city of Qom.
October 25, 2009 – IAEA inspectors make their first visit to Iran’s newly disclosed nuclear facility near Qom.
February 18, 2010 – In a statement, the IAEA reports that it believes Iran may be working in secret to develop a nuclear warhead for a missile.
August 21, 2010 – Iran begins fueling its first nuclear energy plant, in the city of Bushehr.
December 5, 2010 – Ali Akbar Salehi, Iran’s atomic chief and acting foreign minister, announces that Iran’s nuclear program is self-sufficient and that Iran has begun producing yellowcake, an intermediate stage in processing uranium.
January 8, 2011 – Salehi reports that Iran can now create its own nuclear fuel plates and rods.
September 4, 2011 – Iran announces that its Bushehr nuclear power plant joined the electric grid September 3, making it the first Middle Eastern country to produce commercial electricity from atomic reactors.
November 8, 2011 – The IAEA releases a report saying that it has “serious concerns” and “credible” information that Iran may be developing nuclear weapons.
January 9, 2012 – The IAEA confirms that uranium enrichment has begun at the Fordo nuclear facility in the Qom province in northern Iran.
January 23, 2012 – The European Union announces it will ban the import of Iranian crude oil and petroleum products.
January 29, 2012 – A six-member delegation from the IAEA arrives in Tehran for a three-day visit, shortly after the EU imposes new sanctions aimed at cutting off funding to the nuclear program.
February 15, 2012 – Iran loads the first domestically produced nuclear fuel rods into the Tehran research reactor.
February 21, 2012 – After two days of talks in Iran about the country’s nuclear program, the IAEA expresses disappointment that no progress was made and that their request to visit the Parchin military base was denied.
March 28, 2012 – Discussions regarding Iran’s nuclear future stall.
April 14, 2012 – Talks resume between Iran and six world powers over Iranian nuclear ambitions in Istanbul, Turkey.
May 25, 2012 – An IAEA report finds that environmental samples taken at the Fordo fuel enrichment plant near the city of Qom have enrichment levels of up to 27%, higher than the previous level of 20%.
June 18-19, 2012 – A meeting is held between Iran and the P5+1 (United States, France, Russia, China, Great Britain and Germany) in Moscow. No agreement is reached.
June 28, 2012 – Iranian negotiator, Saeed Jalili writes to European Union foreign policy chief Catherine Ashton warning world powers to avoid “unconstructive measures” such as the oil embargo that’s about to go into effect and that was agreed upon by the EU in January.
July 1, 2012 – A full embargo of Iranian oil from the EU takes effect.
August 30, 2012 – A UN report finds that Iran has stepped up its production of high-grade enriched uranium and has re-landscaped Parchin, one of its military bases, in an apparent effort to hamper a UN inquiry into the country’s nuclear program.
January 12, 2014 – It is announced that Iran will begin eliminating some of its uranium stockpile on January 20.
January 20, 2014 – The European Union announces that it has suspended certain sanctions against Iran for six months.
February 20, 2014 – Following talks in Vienna, EU foreign policy chief Catherine Ashton and Iranian Foreign Minister Mohammad Javad Zarif announce that a deal on the framework for comprehensive negotiations over Tehran’s nuclear program has been reached.
November 24, 2014 – The deadline for a final nuclear agreement between Iran and the UN Security Council’s P5+1 countries has been set for July 1, 2015.
July 20, 2015 – The UN Security Council endorses the nuclear deal.
September 20, 2017 – Rouhani says, “It will be a great pity if this agreement were destroyed by rogue newcomers to the world of politics,” in a clear reference to Trump’s address to the UN General Assembly on September 19th, where he offered scathing criticism of both Iran and the 2015 international agreement.