Iran Nuclear Milestones: 1967-2013

June 1, 2013

Publication Type: 

  • Weapon Program Background Report

Weapon Program: 

  • Nuclear

Mentioned Suspect Entities & Suppliers: 

1967: Start-up of the U.S.-supplied 5-megawatt Tehran Research Reactor (TRR).

1970: Iran signs the Nuclear Nonproliferation Treaty (NPT).

1974: Atomic Energy Organization of Iran (AEOI) is established.

1979: German construction of the Bushehr nuclear power reactors, begun in the mid-1970s, is suspended.

Mid-1980s: Iran conducts laboratory scale experiments to produce heavy water at the Esfahan Nuclear Technology Center (ENTC).

1981-93: Iran carries out bench scale preparation of UO2 (uranium dioxide) at ENTC, and bench scale preparation of several uranium compounds, including UF6 (uranium hexafluoride), at the Tehran Nuclear Research Centre (TNRC).

1985: Iran launches a centrifuge enrichment program by searching available technical literature.

1987: Iran receives an offer from a foreign intermediary that includes a disassembled P-1 centrifuge, drawings and specifications for centrifuge production and for a "complete plant," and materials for 2,000 centrifuge machines; Iran claims to have received only drawings and some centrifuge components from the intermediary.

1987-88: Bushehr reactors are heavily damaged by Iraqi bombing raids.

1988: Iran approves a project for the production of polonium-210 in the Tehran Research Reactor; in conjunction with beryllium, polonium-210 can be used as a neutron initiator in some nuclear weapon designs.

1988: Iran signs an agreement with Argentina for the provision of fuel elements for the Tehran Research Reactor, containing 115.8 kg of uranium enriched to up to 20% U-235.

1988-93: Iran irradiates 7 kg of UO2 targets at the Tehran Research Reactor and extracts small quantities of plutonium from some of the targets.

1988-95: Iran conducts centrifuge research and development at TNRC.

1990: Iran signs a ten-year nuclear cooperation agreement with China.

1991: Iran illicitly imports 1,800 kg of uranium in the form of UF4 (uranium tetrafluoride), UF6, and UO2.

1991-2000: Iran's secret laser enrichment program consumes 30 kg of undeclared uranium metal. Iran claims to have achieved an average enrichment level of 8-9% U-235, with some samples approaching 15% U-235.

1992: After a week-long inspection in Iran, an International Atomic Energy Agency (IAEA) team finds no evidence that Iran has a nuclear weapon program.

1993: The Central Intelligence Agency (CIA) says Iran is 8-10 years away from acquiring nuclear weapons and says foreign assistance will be critical to the effort.

1994: Iran signs a contract with China's National Nuclear Corporation for the supply of two 300-megawatt power reactors and continues to shop for a heavy water research reactor.

1994-96: Iran receives drawings for the P-1 centrifuge, components for 500 P-1 machines, and drawings for the more advanced P-2 centrifuge.

1995: Iran signs a contract with Russia to complete one of the Bushehr reactors.

July 1995: Iran purifies some of the plutonium extracted between 1988 and 1993 at TNRC and prepares a disc from the solution.

Mid-1990s: Iran decides to construct a heavy water reactor.

October 1997: The U.S. reveals that, in "written, confidential communications" to U.S. officials, China has pledged that it will not engage in new nuclear cooperation with Iran. The pledge exempts two existing Chinese projects in Iran: a "Zero Power Reactor" and a "Zirconium Tube Factory."

February 1998: American pressure forces Turboatom, a Ukrainian manufacturer of steam turbines, to abandon its $45 million deal to supply turbines to Bushehr.

March 1998: The CIA reports that Iran is "attempting to acquire fissile material and technology for weapons development" under the guise of establishing a nuclear fuel cycle for its civilian energy program.

April 1998: Russia proposes to build a research reactor in Iran fueled by 20% enriched uranium.

August 1998: Iran purifies additional plutonium extracted between 1988 and 1993 at TNRC and prepares a second disc from the solution.

1999-2002: Iran conducts a series of undeclared centrifuge tests at the Kalaye Electric Company. Using imported UF6, Iran achieves an enrichment level of 1.2% U-235.

April 1999: The Izhorskiye Zavod machine-building company of St. Petersburg begins production of equipment for the primary circuit at Bushehr, including the reactor vessel, steam generator casing, and internals.

2000: Construction begins on a uranium ore concentration plant at Gchine, known as "Project 5/15."

March 2000: The Iran Nonproliferation Act is signed into law, authorizing the President to sanction foreign persons for proliferation-related transfers to Iran since January 1, 1999.

April 2000: The Czech government, under pressure from the United States, bans companies from supplying parts to Bushehr. The ZVVZ Milevsko company had planned to provide air conditioning equipment.

June 2000: Russia's deputy minister for atomic energy says the Bushehr plant will be completed in 2002. Russia is expected to earn $1 billion from the project.

July 2000: Iran provides the IAEA with preliminary design information on the Uranium Conversion Facility (UCF) under construction at ENTC.

October 2000: The Director of the CIA's Nonproliferation Center testifies before Congress that Iran is attempting to develop the capability to produce both plutonium and highly enriched uranium (HEU).

March 2001: After pressure from the United States, Russia reportedly cancels plans to sell Iran laser equipment that could be used to support uranium enrichment.

Early 2002: The AEOI contracts with a private company to develop the P-2 centrifuge. The company develops carbon composite rotors for the centrifuge and conducts some mechanical tests without nuclear material.

Early 2002: Iran's Ministry of Defense allegedly begins a warhead development program that involves the design of a re-entry vehicle for the Shahab-3 missile; this re-entry vehicle is assessed by the IAEA as "quite likely" able to accommodate a nuclear warhead.

August 2002: The National Council of Resistance of Iran (NCRI), an Iranian opposition group, reveals the existence of a secret nuclear facility at Natanz and a heavy water facility at Arak. According to the NCRI, the two sites are operated under the cover of front companies, Kala-Electric and the Mesbah Energy Company.

September 2002: Iran announces at the IAEA General Conference that it has an "ambitious" plan to construct, within the next 20 years, nuclear power plants with a total capacity of 6,000 MW.

December 2002: The existence of nuclear facilities at Arak (heavy water production plant) and Natanz (fuel enrichment complex) is revealed by commercial satellite photographs.

February 2003: During discussions held with the IAEA, Iranian authorities acknowledge that a workshop at Kalaye had been used to produce centrifuge components, but claim that it had not enriched any uranium.

9 February 2003: Iranian President Mohammad Khatami announces that Iran is preparing to exploit uranium deposits discovered near Yazd, is building a yellowcake production plant nearby, is building an enrichment plant near Kashan, has completed a uranium oxide plant in Isfahan, and plans to build a fuel production facility.

21-22 February 2003: IAEA Director General Mohamed ElBaradei visits two new uranium enrichment facilities under construction at Natanz: a pilot fuel enrichment plant (PFEP) intended to hold 1,000 centrifuges, and a large commercial-scale fuel enrichment plant (FEP), intended to hold more than 50,000 centrifuges. Iran also confirms the construction of a heavy water production plant at Arak.

5 May 2003: Iran informs the IAEA of its intention to construct a heavy water research reactor, the 40 MW(th) Iran nuclear research reactor (IR-40), at Arak. Iran also declares its intention to begin construction of a fuel manufacturing plant at Esfahan.

27 May 2003: The NCRI claims that Iran is operating two nuclear enrichment sub-stations for its main site at Natanz. According to the NCRI, the two sites are located in the Hashtgerd region, at Ramandeh, and at Lashkar Abad.

25 June 2003: Iran introduces UF6 into the first centrifuge at Natanz.

9-12 August 2003: The IAEA informs Iran that sampling results from the pilot plant at Natanz reveal particles of two types of HEU, indicating the possible presence of undeclared nuclear material. Iran claims that the contamination came from imported centrifuge components.

19 August 2003: Iran begins testing a small ten-machine centrifuge cascade at Natanz with UF6. The IAEA reports that the centrifuges at Natanz have been recognized as "an early European design;" they are referred to in subsequent IAEA reports as P-1 or IR-1 centrifuges.

October 2003: The IAEA reports that Iran is finalizing the installation of a 164 machine cascade at the Natanz pilot plant.

21 October 2003: Foreign Ministers from Britain, France and Germany meet with Iranian officials and release a joint statement in which Iran agrees to adhere to the Additional Protocol and agrees voluntarily to suspend all uranium enrichment and reprocessing activities.

10 November 2003: Iran informs the IAEA that it will allow enhanced inspections under the Additional Protocol pending its entry into force, and that it will suspend all enrichment-related and reprocessing activities as of November 10.

18 December 2003: Iran signs the Additional Protocol.

1 February 2004: A senior Pakistani official tells journalists that A.Q. Khan has signed a detailed confession admitting that between 1989 and 1991 he provided Iran with designs, drawings and components for the production of fuel for nuclear weapons.

24 February 2004: Iran informs the IAEA that it will stop manufacturing, testing and assembling centrifuges as of March. However, Iran says that some centrifuge manufacturing will continue under existing contracts.

24 February 2004: The IAEA reports that Iran failed to declare its work on the more advanced P-2 centrifuge, and on efforts to produce polonium-210, which can be used as a neutron initiator in some nuclear weapons, and which took place between 1989 and 1993. In addition, environmental samples taken from Kalaye show greater than trace quantities of uranium enriched to 36% U-235.

29 March 2004: The head of the AEOI announces the suspension of centrifuge construction.

21 May 2004: Iran submits its initial declaration to the IAEA in compliance with the Additional Protocol. In the declaration, Iran provides information on the Gchine mine and mill, the Saghand mine, and the Ardakan Yellowcake Production Plant.

1 June 2004: In a report, the IAEA confirms Iran's suspension of enrichment and reprocessing activities, and concludes that Iran produced milligram quantities of plutonium, rather than the 200 micrograms estimated by Iran.

28 June 2004: The IAEA takes environmental samples at the Lavisan-Shian site in Tehran, which has been linked to alleged undeclared nuclear activities. According to Iran, the site was razed by the Municipality of Tehran during a two to three month period beginning in December 2003.

July 2004: Iran removes seals from equipment and centrifuge components located at Natanz, Pars Trash, and Farayand Technique and returns the seals to the IAEA.

August 2004: Iran begins processing about 37 tons of yellowcake at the UCF.

1 September 2004: The IAEA reports that it found particles of 54% U-235, with U-236 contamination, in samples taken from the surfaces of imported centrifuge components, which supports Iran's claim that the HEU contamination found at Kalaye and Natanz came from imported components. However, information from the country that provided the components indicates that not all Iranian HEU contamination may have originated in that country.

15 November 2004: The governments of France, Germany, and Britain, with the support of the European Union (E3/EU), reach an agreement with Iran in which Iran again agrees to suspend "all enrichment related and reprocessing activities" in return for the promise of nuclear, technological and economic cooperation.

15 November 2004: The IAEA releases a report listing more than a dozen failures by Iran to meet its Safeguards obligations. The report reveals that uranium enriched to about 70% U-235 has been found in samples taken from Kalaye and on imported components stored at Natanz and Pars Trash.

17 November 2004: The NCRI accuses Iran of relocating nuclear activities from the Lavisan-Shian site to the Modern Defensive Readiness and Technology Center, both controlled by the Ministry of Defense.

18 November 2004: U.S. Secretary of State Colin Powell tells the media that the U.S. government has information suggesting that Iran is working on designs for mating a nuclear warhead to a missile.

22 November 2004: The IAEA installs seals and other tamper-indicating devices at the UCF to verify that no additional yellowcake is introduced into the uranium conversion process and that there is no further production of UF6.

18 February 2005: At the UCF, Iran completes conversion of 37 tons of yellowcake into ammonium uranyl carbonate (AUC), UF4 and UF6. The IAEA seals the UF4 and UF6 produced during this process and installs and seals cameras at UF6 withdrawal stations to ensure that there is no undeclared withdrawal of the UF6 remaining in the plant's process lines.

27 February 2005: Tehran and Moscow reportedly sign an agreement in which Russia would supply fuel for the Bushehr reactor, and Iran would return all spent fuel to Russia.

March 2005: The IAEA confirms that construction on the heavy water reactor building at Arak has started.

11 March 2005: The United States decides to stop blocking Iran's application to join the World Trade Organization and to consider on a case-by-case basis its attempts to buy spare parts for civilian aircraft, in support of European diplomacy with Iran.

May 2005: A U.S. National Intelligence Estimate on Iran assesses with "high confidence" that Iran is determined to develop nuclear weapons and that Iran could produce enough fissile material for a weapon by the end of the decade, if Iran progressed more rapidly than it has to date.

25 May 2005: Centrifuge components and uranium samples from Pakistan are reportedly received by the IAEA's main laboratory, where they will be compared with traces of enriched uranium found in Iran.

13 June 2005: The IAEA reveals that Iran conducted plutonium separation experiments as recently as 1998, five years beyond the date previously cited by Iran.

28 July 2005: The NCRI alleges that Iran is using front companies to purchase maraging steel, which can be used to make solid rocket motor cases, propellant tanks, missile interstages, and centrifuge rotors.

5 August 2005: E3/EU offer Iran assured access to light-water reactor fuel, confirm support for Iranian accession to the WTO, and support the sale of civilian aircraft parts to Iran. In exchange, Iran must abandon its heavy water reactor at Arak and end fuel cycle activities other than the construction and operation of light water power and research stations, subject to future review.

8 August 2005: Iran rejects the European proposal, citing a disregard for Iran's right to access nuclear fuel production and uranium enrichment. On the same day, Iran begins feeding yellowcake into the first part of the process line at the UCF.

2 September 2005: The IAEA reports that samples taken from centrifuge components received from a Member State support Iran's claims about the foreign origin of most HEU contamination, but that it is not yet possible "to establish a definitive conclusion with respect to all of the contamination, particularly the LEU contamination."

24 September 2005: The IAEA Board of Governors finds Iran in "non compliance" with its NPT Safeguards Agreement and refers Iran to the U.N. Security Council.

16 November 2005: Iran begins a new conversion campaign at the UCF using 150 drums of yellowcake.

18 November 2005: The IAEA reveals that Iran possesses a document with instructions on how to reduce UF6 to metal and how to cast and machine enriched, natural and depleted uranium metal into hemispheres, a form used in nuclear weapon components.

January 2006: Iran removes IAEA seals at Natanz, Farayand Technique, and Pars Trash and begins "substantial renovation" of the gas handling system at the Natanz pilot plant and quality control of centrifuge components and some rotor testing at Farayand Technique and Natanz.

31 January 2006: The IAEA reveals Iran's alleged "Green Salt Project," which involves work on the conversion of U02 into UF4 ("green salt"), tests related to high explosives, and designs for a missile re-entry vehicle, all of which appear to have administrative interconnections.

6 February 2006: Iran informs the IAEA that it will suspend implementation of the Additional Protocol.

11 February 2006: At the Natanz pilot plant, Iran begins feeding UF6 gas into a single P-1 machine, and four days later into a 10-machine cascade.

March 2006: Iran completes and begins testing the 164-machine cascade at Natanz using UF6.

29 March 2006: The U.N. Security Council issues a presidential statement calling on Iran to suspend all enrichment and reprocessing activities.

13 April 2006: Iran reports that it has enriched uranium to 3.6%, a level which IAEA sampling tends to confirm.

31 May 2006: U.S. Secretary of State Condoleezza Rice announces that the United States is willing to conduct direct talks with Iran "as soon as Iran fully and verifiably suspends its enrichment and reprocessing activities."

June 2006: Iran again feeds UF6 into the first 164-centrifuge cascade at its Natanz pilot plant, claiming to achieve an enrichment level of 5% U-235.

31 July 2006: The U.N. Security Council adopts resolution 1696, which "demands … that Iran suspend all enrichment-related and reprocessing activities" by August 31, or face possible sanctions.

26 August 2006: Iranian President Mahmoud Ahmadinejad inaugurates the heavy water facility at Arak. The AEOI reportedly claims that the facility is capable of producing heavy water with 99.8% purity.

13 October 2006: Iran begins injecting UF6 gas into the second 164-centrifuge cascade at its Natanz pilot plant.

23 December 2006: The U.N. Security Council adopts resolution 1737, imposing sanctions to prevent the transfer to Iran of materials, as well as technical or financial assistance, which might contribute to Iranian nuclear and ballistic missile development. The resolution also designates Iranian persons and entities for which financial resources are to be frozen.

31 January 2007: Iran transfers some 8.7 tons of UF6 to its commercial-scale Fuel Enrichment Plant (FEP) at Natanz.

9 February 2007: The IAEA decides to end or limit four of fifteen national technical cooperation projects in Iran, and eighteen of forty regional or interregional projects involving Iran, in accordance with U.N. Security Council resolution 1737.

17 February 2007: IAEA inspectors are informed that Iran has installed and is operating under vacuum two 164-centrifuge cascades at its FEP, and that two additional such cascades are under construction.

24 March 2007: The U.N. Security Council adopts resolution 1747, imposing further sanctions to prevent the transfer of arms and financial assistance to Iran, and designating additional Iranian persons and entities for which financial resources are to be frozen.

29 March 2007: Iran reverts to an arrangement under which design information on the construction of new nuclear facilities is provided to the IAEA "normally not later than 180 days" before the introduction of nuclear material; the IAEA contests the decision.

23 April 2007: The European Union adopts an arms embargo against Iran and freezes the assets of 23 Iranian entities linked to nuclear or missile proliferation.

13 May 2007: Iran is operating eight 164-centrifuge cascades at its FEP, with two additional cascades being vacuum tested and three more under construction. An enrichment level of 4.8% U-235 has been achieved at the plant, according to Iran.

21 August 2007: The IAEA and Iran agree to a "work plan" for the resolution of outstanding issues, which include: experiments involving plutonium and polonium-210; the acquisition of P-1 and P-2 centrifuge technology; the origin of uranium contamination; Iran's possession of a document describing how to produce enriched uranium metal hemispheres; activities at the Gchine mine; and alleged studies involving uranium conversion, high explosive testing and the design of a missile re-entry vehicle.

30 August 2007: The IAEA reports that questions regarding Iran's past plutonium experiments have been resolved.

November 2007: In a U.S. National Intelligence Estimate, the intelligence community judges "with high confidence" that Iran halted its nuclear weapon program in fall 2003, but assesses "with moderate-to-high confidence" that Iran "at a minimum is keeping open the option to develop nuclear weapons." The intelligence community further judges with "moderate confidence" that Iran would be capable of producing enough HEU for one nuclear weapon between 2010 and 2015.

3 November 2007: Iran is operating eighteen 164-centrifuge cascades with UF6 at the FEP; IAEA measurements indicate a maximum enrichment level of 4% U-235.

8 November 2007: Iran informs the IAEA that it is conducting mechanical tests on a "new generation of centrifuge design."

15 November 2007: The IAEA concludes that Iran's statements regarding the past acquisition of P-1 and P-2 centrifuge technology are largely "consistent" with Agency findings.

12 December 2007: The IAEA verifies the inventory of uranium processed at the FEP: 1,670 kg of UF6 have been processed, yielding about 75 kg of low-enriched UF6.

January 2008: Iran installs a new subcritical centrifuge (IR-2) at the Natanz pilot plant, including a single machine and a 10-machine cascade; the single machine is tested with UF6.

February 2008: Iran receives fresh fuel assemblies (reportedly 82 tons) for its Bushehr reactor from Russia.

22 February 2008: The IAEA reports that questions regarding Iran's polonium-210 experiments and the Gchine uranium mine and mill are "no longer outstanding at this stage;" the IAEA also reports that Iran's explanations regarding the source of uranium contamination found on equipment at a technical university and the nuclear procurement activities of a former head of the Physics Research Center (PHRC) are "not inconsistent" with the Agency's current knowledge.

25 February 2008: IAEA Deputy Director General Olli Heinonen briefs member states, including Iran, on allegations of Iranian nuclear weapon development, including interconnected projects, overseen by Iran's Ministry of Defense Armed Forces and Logistics (MODAFL), for converting UO2 to UF4 (Green Salt Project), for testing high power explosives, and for designing a missile re-entry vehicle.

3 March 2008: The U.N. Security Council adopts resolution 1803, extending travel restrictions and asset freezes - and in some cases instituting a travel ban - to additional Iranian entities, and barring Iran from buying almost all nuclear and missile-related technology; the resolution also requests countries to inspect suspect cargoes to and from Iran, and to "exercise vigilance" over public financial support for business with Iran and transactions involving Iranian banks, particularly Bank Saderat and Bank Melli.

April 2008: Iran processes UF6 in a new sub-critical centrifuge (IR-3) installed at the Natanz pilot plant.

7 May 2008: At the FEP, Iran is operating 3,280 IR-1 centrifuges with UF6; 2,624 additional such machines are being installed.

June 2008: Iran receives a nuclear incentives proposal on behalf of Britain, China, France, Germany, Russia, and the United States (the P5+1). The proposal promises assistance with light-water reactors, guaranteed nuclear fuel supply, and, in the future, support for nuclear research and development.

23 June 2008: The European Union imposes financial sanctions on 26 Iranian entities linked to nuclear and missile work, including Bank Melli, its branches and subsidiaries.

July 2008: A meeting between Iran and P5+1 countries ends in deadlock when Iran fails to respond to the "freeze for freeze" offer, under which no additional U.N. sanctions would be voted if Iran refrained from increasing its uranium enrichment capacity.

September 2008: The U.N. Security Council adopts resolution 1835, which calls on Iran to comply with previous Security Council resolutions by freezing uranium enrichment but does not impose additional sanctions.

October 2008: Intelligence reports allege that Iran has tested ways of recovering highly enriched uranium from fuel used in the Tehran research reactor and converting the material into metal.

November 2008: Iran is reportedly using exclusively domestically mined, milled and converted uranium as the feedstock for its enrichment program, after overcoming difficulties at its Uranium Conversion Facility.

1 February 2009: An IAEA inventory at FEP reveals that Iran processed 9,956 kg of UF6 between February 2007 and November 2008, yielding 839 kg of low-enriched UF6.

9 February 2009: The process line for the production of heavy water reactor fuel is complete and fuel rods are being produced at the Fuel Manufacturing Plant.

25 February 2009: A pre-commissioning ceremony is held at the Bushehr nuclear power plant; test run of the plant marks the end of the construction phase.

March 2009: Iran allegedly receives over 100 Swiss-origin pressure transducers, with nuclear applications, via Chinese and Taiwanese companies.

March-May 2009: Iran begins testing several new centrifuges at the Natanz pilot plant, including a modified version of the IR-2 (the IR-2m) and the IR-4.

9 April 2009: Iranian President Mahmoud Ahmadinejad inaugurates the Fuel Manufacturing Plant, which Iran claims is able to produce, annually, 10 tons of natural uranium fuel for the 40 megawatt Arak heavy water reactor and 30 tons of low-enriched uranium fuel for use in light-water reactors.

June 2009: At the FEP, Iran is enriching uranium in 4,920 IR-1 centrifuges; 2,132 additional centrifuges are installed and under vacuum, and 169 centrifuges are installed.

10 August 2009: Iran estimates that it has produced about 366 tons of uranium in the form of UF6 at the UCF since March 2004; an IAEA inventory at the plant largely confirms this estimate.

September 2009: The United States concludes that Iran "is now either very near or in possession already of sufficient low-enriched uranium to produce one nuclear weapon, if the decision were made to further enrich it to weapons-grade."

25 September 2009: The United States, France and Britain reveal that Iran has been building a secret uranium enrichment plant near Qum whose size and configuration is "inconsistent" with a peaceful nuclear program.

1 October 2009: During nuclear talks with the P5+1, Iran agrees to allow the IAEA to inspect the Qum enrichment plant and agrees "in principle" to export its stockpiled low-enriched uranium so that the material can be processed into fuel for the Tehran Research Reactor.

2 October 2009: Leaked excerpts of a draft IAEA report, "Possible Military Dimensions of Iran's Nuclear Program," reveal that Iran may have a program to develop a nuclear payload for delivery on its Shahab-3 missile and that Iran may have developed a high explosive implosion system that could be used in a nuclear weapon. The IAEA assesses that Iran should be able to design and produce a workable implosion device fueled with highly enriched uranium.

19-21 October 2009: A draft technical agreement is concluded between Iran and France, Russia and the United States, under which Iran's low-enriched uranium would be converted into fuel for the Tehran research reactor.

25-28 October 2009: IAEA inspectors visit the recently disclosed Fordow (Fordo) uranium enrichment plant, located 20 km north of Qum, and verify that it is designed to house about 3,000 centrifuges and that it is "at an advanced stage of construction." Iran claims that construction began in 2007 and that the plant will be operational in 2011; the Agency has evidence that construction began earlier.

2 November 2009: At the FEP, Iran is enriching uranium in 3,936 IR-1 centrifuges; 4,756 additional such centrifuges are installed.

4 November 2009: Satellite photographs reportedly suggest that Iran has increased the production rate at its Gchine uranium mine, near the city of Bandar Abbas.

15 November 2009: Iran completes clean out at UCF; 371 tons of UF6 have been produced at the plant between March 2004 and August 2009.

22 November 2009: Results of an IAEA inventory at the FEP reveal that Iran processed 21,140 kg of UF6 between February 2007 and November 2009, yielding a total of 1,808 kg of low enriched UF6.

27 November 2009: The IAEA Board of Governors adopts a resolution urging Iran immediately to suspend construction on the enrichment plant at Qom (the Fordow plant) and to comply with Security Council resolutions.

9 January 2010: The IAEA learns that Iran is conducting research and development work on the electrochemical production of uranium metal at the Jabr Ibn Hayan Multipurpose Research Laboratory (JHL) in Tehran.

9 February 2010: Iran begins the production of uranium enriched up to 20% U-235 in a single cascade of 164 IR-1 centrifuges at the Natanz pilot plant.

9 April 2010: Iran claims to have produced and tested a third generation centrifuge, which AEOI chief Ali Akbar Salehi says is six times more efficient than previous models.

May 2010: In a joint declaration with Brazil and Turkey, Iran agrees to send 1,200 kilograms of low-enriched uranium to Turkey in exchange for the provision of 120 kg of fuel for the Tehran Research Reactor.

9 June 2010: The U.N. Security Council adopts resolution 1929, imposing a fourth round of sanctions on Iran. This adds to previous sanctions by extending an asset freeze and travel ban to additional Iranian entities, including some within the Islamic Revolutionary Guard Corps and the Islamic Republic of Iran Shipping Lines, and by barring Iran from acquiring any interest in commercial nuclear activities abroad, and from importing most conventional arms.

23 June 2010: Iran has 17 kg of 20% enriched uranium and can produce up to five kg each month, according to AEOI chief Ali Akbar Salehi.

1 July 2010: U.S. President Barack Obama signs into law the Comprehensive Iran Sanctions, Accountability, and Divestment Act of 2010 (H.R. 2194).  It targets firms that support Iran's energy sector, do business with Iranian entities on the U.S. government blacklist, and sell telecommunication and other sensitive technology to Iran. The law also authorizes state and local governments to divest from firms involved in Iran's energy sector.

13 July 2010: Iran begins enriching uranium to 20% U-235 in a second cascade of 164 IR-1 centrifuges at the Natanz pilot plant, interconnecting it with the first cascade.

July 2010: The European Union, Canada, and Australia adopt new autonomous sanctions against Iran, specifically targeting Iran's energy, banking and shipping sectors.

August 2010: Iran begins transferring fresh fuel to the Bushehr Nuclear Power Plant.

3 September 2010: Japan adopts new sanctions against Iran, specifically targeting Iran's energy, shipping and banking sectors; the assets of 15 Iranian banks are frozen.

8 September 2010: South Korea adopts new financial sanctions against 126 Iranian entities, including the Seoul branch of Bank Mellat, and announces a ban on investment in Iran's energy sector.

18 September 2010: Iran has processed 352 kg of low-enriched UF6 at the Natanz pilot plant since February 2010, yielding 25.1 kg of UF6 enriched to 20% U-235.

17 October 2010: Results of an IAEA inventory at the FEP reveal that Iran processed 34,737 kg of natural UF6 between February 2007 and October 2010, yielding a total of 3,135 kg of low-enriched UF6.

5 November 2010: Of 54 cascades (8,426 IR-1 centrifuges) installed at the FEP, about 29 (4,816 centrifuges) are being fed with UF6. Each installed cascade originally comprised 164 centrifuges; Iran modified six cascades to contain 174 centrifuges.

Mid-November 2010: Iran briefly suspends all uranium enrichment at the FEP and then resumes enrichment in 28 centrifuge cascades on November 22.

29 November 2010: Iranian President Mahmoud Ahmadinejad says that "a cyberbug" may have created "problems for a limited number of our centrifuges." According to security researchers, the Stuxnet worm targets frequency converter drives, which control high-speed motors such as those used to spin centrifuges.

December 2010: Iran ships a consignment of domestically produced "yellowcake" from the Gachin (Gchine) mine to UCF; AEOI chief Ali Akbar Salehi claims that Iran is no longer reliant on imported yellowcake.

January 2011: Norway and Switzerland impose more stringent sanctions on Iran, including restrictions on cooperation in the oil and gas sectors; the new measures bring both countries in line with E.U. legislation.

7 April 2011: The NCRI, an Iranian opposition group, says it has identified a secret industrial site in Tehran’s western suburbs used for manufacturing centrifuge parts. The “Iranian Cutting Tools Factory,” or TABA, produces casings, magnets, molecular pumps, composite tubes, bellows, and centrifuge bases, according to the NCRI.

12 April 2011: Iran confirms it is producing centrifuge components at TABA, but says the site is outside the IAEA’s jurisdiction.

24 May 2011: The European Union implements sanctions against 77 persons or entities associated with Iran’s nuclear or ballistic missile programs, in addition to dozens of front companies operated by the Islamic Republic of Iran Shipping Lines (IRISL), Iran's national shipping company.

24 May 2011: Referring to possible military dimensions to Iran’s nuclear program, the IAEA expresses concern over “experiments involving the explosive compression of uranium deuteride to produce a short burst of neutrons.”

27 August 2011: Iran’s Aerospace Industries Organization (AIO) inaugurates the country’s first carbon fiber production line. Carbon fiber composites can be used to make centrifuge rotors.

September 2011: The Bushehr nuclear power plant joins the national power grid.

September 2011: Iran has processed 720.8 kg of low-enriched UF6 at the PFEP since February 2010, yielding 73.7 kg of UF6 enriched to 20% U-235, according to an IAEA inventory.

October 2011: Results of an annual IAEA inventory at the FEP confirm that Iran has processed 55,683 kg of natural UF6 between February 2007 and October 2011, yielding a total of 4,871 kg of low-enriched UF6.

2 November 2011: Of 54 cascades (approximately 8,000 centrifuges) installed at the FEP, 37 cascades (6,208 centrifuges) are being fed with UF6.

8 November 2011: The IAEA expresses “serious concerns regarding possible military dimensions to Iran’s nuclear programme”  and details what it calls “credible” information about weaponization-related activities.

21 November 2011: Canada prohibits the export of additional items that could be used in Iran's nuclear program and designates additional entities of proliferation concern.

9 December 2011: Expressing “deep and increasing concerns” about Iran’s nuclear program, Japan freezes the assets of 106 entities, three banks, and one individual.

14 December 2011:  Iran begins enriching uranium at the underground Fordow Fuel Enrichment Plant (FFEP) near Qum, feeding low-enriched UF6 into 348 IR-1 centrifuges and producing 20% enriched uranium.

January 2012: Iran increases the number of centrifuges devoted to the production of 20% enriched uranium at the Fordow enrichment plant by 348.  A total of 696 IR-1 centrifuges are operating at the plant.

23 January 2012: The European Union announces new sanctions targeting sources of finance for Iran's nuclear program, including a ban on imports of Iranian crude oil and petroleum and petrochemical products, an asset freeze on Iran's Central Bank, and a prohibition on trade in gold, precious metals, and diamonds with Iranian public bodies.

February 2012: Iran irradiates domestically produced fuel assemblies at the Tehran Research Reactor, including fuel plates and fuel rods containing natural and enriched UO2 and 20% enriched uranium.

April 2012: Iran and the members of the P5+1 meet in Turkey to discuss Iran's nuclear program, the first such meeting in some 15 months.

May 2012: Iran and members of the P5+1 meet in Baghdad to continue discussion about Iran's nuclear program.  E.U. foreign policy chief Catherine Ashton says that the two sides found "some common ground," but that "significant differences remain."  P5+1 proposals focus on winning a suspension of enrichment to 20% and the export of Iran's current stock of this material, in exchange for spare parts for Iran's civilian aircraft and nuclear safety assistance.

June 2012:  Nuclear talks in Moscow between the P5+1 and Iran end without a breakthrough.

1 July 2012: European Union sanctions targeting sources of finance for Iran's nuclear program take effect, including a ban on imports of Iranian crude oil and a prohibition on providing insurance for the transport of Iranian oil.

30 August 2012: The IAEA reports that satellite imagery shows demolition of buildings at the Parchin military site and “significant ground scraping.” This site has been linked to nuclear weapon development.

1 September 2012: Iran and North Korea sign a science and technology cooperation agreement. Supreme Leader Khameini declares that the two countries have “common enemies.”

15 September 2012: Iran has produced 129.1 kg of UF6 enriched to 20% U-235 at the PFEP, according to an IAEA inventory.

October 2012: The European Union expands export restrictions on Iran to include graphite, metals, and software for industrial processes, and adopts additional restrictive measures on Iran's transport, financial, and energy sectors.

October 2012: Results of an annual IAEA inventory at the FEP confirm that Iran has processed 85,644 kg of natural UF6 between February 2007 and October 2012, yielding a total of 7,451 kg of low-enriched UF6.

10 November 2012: Of 61 fully installed cascades at the Natanz FEP (10,414 centrifuges), 54 are being fed with UF6. Preparatory installation work is completed for 28 other centrifuge cascades, and is ongoing in relation to 54 others. All the centrifuges are IR-1s.

November 2012:  The IAEA reports that Iran has completed centrifuge installation at the Fordow plant, which now holds 2,784 IR-1machines, of which 696 are enriching uranium. The plant has produced an estimated 95.5 kg of UF6 enriched to 20% U-235 since the beginning of operations in December 2011.

11 December 2012: Canada expands sanctions against Iran, targeting 98 individuals and entities in oil and gas, mining, metals and shipping.

21 December 2012: The European Union sanctions 18 entities and one individual because of their involvement in nuclear activities or their support for the Iranian government.

January 2013: The Bushehr reactor comes back online after a two month shutdown, during which the reactor's fuel was removed from the core.

6 February 2013: Iran begins installing IR-2m centrifuges at the Natanz FEP. The IAEA notes this is “the first time that centrifuges more advanced than the IR-1 have been installed in FEP.”

10 February 2013: At the Fordow site, Iran estimates it has now produced 129.9 kg of UF6 enriched to 20% U-235.

23 February 2013: Iran announces the discovery of new uranium deposits and selects 16 sites for the construction of nuclear power plants.

27 February 2013: The P5+1 negotiating partners meet with Iran in Almaty, Kazakhstan and propose that Iran keep enough 20% enriched uranium to fuel a research reactor and that Iran suspend enrichment work at the Fordow plant rather than close the plant. No deal is reached.

2 April 2013: In an interview with the Associated Press, IAEA Director General Yukiya Amano says that the Agency has "information indicating that Iran was engaged in activities relevant to the development of nuclear explosive devices in the past and now.

6 April 2013: Negotiations in Almaty, Kazakhstan between Iran and the P5+1 over Iran’s nuclear program end in failure.

9 April 2013: Iran starts production at two uranium mines – Saghand 1 and 2 – and at the Shahid Rezaeinejad yellowcake plant at Ardakan.

6 May 2013: The IAEA confirms that the reactor vessel has arrived at the Arak heavy water reactor site and that “major components” have been installed at the reactor.

22 May 2013: The IAEA reports that a "significant proportion" of the disputed Parchin military site has been covered with asphalt.

15 May 2013: Of 79 IR-1 cascades (13,555 centrifuges) at the FEP, 53 cascades are being fed with UF6.  Preparatory installation work has been completed for 46 other cascades, and is ongoing for one other.  Four IR-2m cascades (689 centrifuges) are also installed at the FEP, though none are being fed with UF6.

29 May 2013: Canada adopts a total ban on imports from and exports to Iran and adds 30 individuals and 82 entities to its blacklist because of their involvement in proliferation activities.  This list contains a total of 508 entities and 78 individuals.