Iran's nuclear program began during the 1950s. Construction of a U.S.-supplied research reactor, called the Tehran Research Reactor (TRR), located in Tehran began in 1960; the reactor went critical in 1967. During the 1970s, Tehran pursued an ambitious nuclear power program. According to contemporaneous U.S. documents, Iran wanted to construct 10-20 nuclear power reactors and produce more than 20,000 megawatts of nuclear power by 1994. Iran also began constructing a light-water nuclear power reactor near the city of Bushehr, and it considered obtaining uranium enrichment and reprocessing technology. Iran took steps to demonstrate that it was not pursuing nuclear weapons. For example, Tehran signed the nuclear Nonproliferation Treaty (NPT) in 1968 and ratified it in 1970. Iran also submitted a draft resolution to the U.N. General Assembly in 1974 that called for establishing a nuclear-weapons-free zone in the Middle East. Nevertheless, mid-1970s U.S. intelligence reports expressed concern that Iran might pursue a nuclear weapons program. Although Iran cancelled its nuclear program after its 1979 revolution, a 1981 Department of State draft paper argued that Iran might develop a nuclear weapons program in response to a then-suspected Iraqi nuclear weapons program, although Iran was not one of several countries of "near to medium term proliferation concern" cited in the paper. Tehran "reinstituted" its nuclear program in 1982. According to International Atomic Energy Agency (IAEA) reports, Iran conducted experiments during the 1980s and early 1990s related to uranium conversion, heavy-water production, and nuclear reactor fuel fabrication. A 1985 National Intelligence Council report, which cited Iran as a potential "proliferation threat," stated that Tehran was "interested in developing facilities that ... could eventually produce fissile material that could be used in a [nuclear] weapon." The report, however, added that it "would take at least a decade" for Iran to do so. A 1986 CIA report went further, citing "the advantage of long-range missiles to deliver warheads quickly, virtually without warning, and-unlike aircraft-without facing any defense" as a "factor" that would incentivize Iranian development of nuclear weapons "in the late 1990s." A 1995 U.S. intelligence report stated that Iran was "aggressively pursuing a nuclear weapons capability and, if significant foreign assistance were provided, could produce a weapon by the end of the decade." Somewhat less urgently, an Arms Control and Disarmament Agency report covering 1995 observed that "Iran's rudimentary program has apparently met with limited success so far, [but] we believe Iran has not abandoned its efforts to expand its nuclear capabilities with a view to supporting nuclear weapons development." In 1996 congressional testimony, then-Director of Central Intelligence John Deutch described Iranian efforts to acquire from the former Soviet Union fissile material for a nuclear weapon: In an attempt to shorten the timeline to a weapon, Iran has launched a parallel effort to purchase fissile material, mainly from sources in the former Soviet Union. Iranian agents have contacted officials at nuclear facilities in Kazakhstan on several occasions, attempting to acquire nuclear-related materials. For example, in 1992, Iran unsuccessfully approached the Ulba Metallurgical Plant to obtain enriched uranium. In 1993, three Iranians believed to have had connections to Iran's intelligence service were arrested in Turkey while seeking to acquire nuclear material from smugglers from the former Soviet Union. More recently, the Iranian government has said that it plans to expand its reliance on nuclear power to generate electricity. This program will, Tehran says, reduce Iran's oil and gas consumption and allow the country to export additional fossil fuels; the previous Iranian regime also made this argument. Iran has begun to operate the Bushehr reactor, and Tehran says it intends to build additional reactors to generate 20,000 megawatts of power within the next 20 years. The 2015 Joint Comprehensive Plan of Action (JCPOA) requires Iran to refrain from building heavy-water-moderated reactors for 15 years. Pursuant to the agreement, Iran has pledged to refrain from constructing any such reactors indefinitely. Iranian officials say that Tehran has begun design work on its first indigenously produced light-water reactor, to be constructed at Darkhovin. According to official U.S. and Iranian sources, France agreed to construct the reactor during the 1970s but ended the project after the 1979 revolution in Iran. Atomic Energy Organization of Iran (AEOI) President Ali Akbar Salehi stated in September 2016 that "we are almost about to sign a contract for designing" the reactor, "but it will take a rather long time." Iranian officials have repeatedly asserted that the country's nuclear program is exclusively for peaceful purposes (see Appendix A ). Nevertheless, prior to the JCPOA, the United States and other governments argued that Iran may be pursuing, at a minimum, the capability to produce nuclear weapons. Discerning a peaceful nuclear program from a nuclear weapons program can be difficult because much nuclear technology is dual-use. In addition, military nuclear programs may coexist with civilian programs, even without an explicit governmental decision to produce nuclear weapons. Jose Goldemberg, Brazil's former secretary of state for science and technology, observed that a country developing the capability to produce nuclear fuel does not have to make an explicit early [political] decision to acquire nuclear weapons. In some countries, such a path is supported equally by those who genuinely want to explore an energy alternative and by government officials who either want nuclear weapons or just want to keep the option open. Some analysts argue that several past nuclear programs, such as those of France, Sweden, and Switzerland, illustrate this approach. A Swedish official involved in that country's nuclear weapons program "argued that the main aim should be the generation of nuclear energy, with plutonium production, which would make possible the manufacture of nuclear weapons as a side-effect." Moreover, a 1975 U.S. intelligence assessment argued that countries might develop an "unweaponized" nuclear explosive device "to further their political, and even military, objectives." The main source of proliferation concern generated by Iran's nuclear program has been Tehran's construction of gas centrifuge uranium-enrichment facilities. Gas centrifuges enrich uranium by spinning uranium hexafluoride gas at high speeds to increase the concentration of the uranium-235 isotope. Such centrifuges can produce both low-enriched uranium (LEU), which can be used in nuclear power reactors, and highly enriched uranium (HEU), which is one of the two types of fissile material used in nuclear weapons. HEU can also be used as fuel in certain types of nuclear reactors. Iran also has a uranium-conversion facility, which converts uranium ore concentrate into several compounds, including uranium hexafluoride. This program is currently constrained by the JCPOA. German Minister of State Niels Annen argued in a February 19, 2019, speech that the JCPOA "effectively prevents Iran from acquiring a nuclear weapon for as long as the agreement stands." However, following the May 8, 2018, U.S. announcement that the United States would no longer participate in the JCPOA and would reimpose sanctions that had been suspended pursuant to the agreement, Iranian President Hassan Rouhani ordered the AEOI to "go ahead with adequate preparations to resume enrichment at the industrial level without any limit." A year later, Rouhani announced additional Iranian responses. (see Appendix C , "Multilateral Diplomacy Concerning Iran's Nuclear Program"). Iranian officials have asserted that the country can rapidly reconstitute its fissile material production capability, although Tehran has adhered to the JCPOA-specified limits. Iran claims that it wants to produce LEU fuel for its planned light-water nuclear power reactors, as well as the Tehran Research Reactor (TRR) and other planned future research reactors. The latter reactors will be used to produce isotopes for medical purposes, according to Tehran. Although Iran has expressed interest in purchasing nuclear fuel from other countries, the government asserts that the country should have an indigenous enrichment capability as a hedge against possible fuel supply disruptions. President Rouhani ordered AEOI President Salehi on December 13, 2016, to provide a plan "for designing and manufacturing nuclear-propulsion system to be used in maritime transportation," as well as producing fuel for such a system. However, Iranian officials have indicated that Tehran would not produce enriched uranium exceeding JCPOA-established enrichment limits. In a January 2018 letter, Iran informed the IAEA of the government's "decision … to construct naval nuclear propulsion in future." Tehran explained in an April 2018 letter to the agency that "[f]or the first five years, no [nuclear] facility will be involved" and the "[n]uclear fuelled engines/reactors will be used for civilian purpose." Salehi stated in early February 2019 that at the project will take "at least 15 years" to complete. A reactor moderated by heavy water, which Iran was constructing at Arak, has also been a source of concern. Although Tehran says that the reactor is intended for the production of radioisotopes for medical purposes, the reactor previously under construction was a proliferation concern because its spent fuel would have contained plutonium well-suited for use in nuclear weapons. Spent nuclear fuel from nuclear reactors contains plutonium, the other type of fissile material used in nuclear weapons. In order to be used in nuclear weapons, however, plutonium must be separated from the spent fuel—a procedure called "reprocessing." Iran has said that it will not engage in reprocessing. This reactor is designed to use natural uranium fuel, which does not require enrichment. Iran has rendered the Arak reactor's original core inoperable pursuant to the JCPOA, which also commits Tehran to redesign and rebuild the reactor based on a design agreed to by the P5+1. In addition to the dual-use nature of the nuclear programs described above, Iran's inconsistent cooperation with the IAEA contributed to suspicions that Tehran had a nuclear weapons program. In the past, Iran has taken actions that interfered with the agency's investigation of its nuclear program, including concealing nuclear activities and providing misleading statements. Then-IAEA Director-General Mohamed ElBaradei explained in a 2008 interview that Iran's cooperation lagged behind IAEA demands: [T]hey [the Iranians] have concealed things from us in the past, but that doesn't prove that they are building a bomb today. They continue to insist that they are interested solely in using nuclear power for civilian purposes. We have yet to find a smoking gun that would prove them wrong. But there are suspicious circumstances and unsettling questions. The Iranians' willingness to cooperate leaves a lot to be desired. Iran must do more to provide us with access to certain individuals and documents. It must make a stronger contribution to clarifying the last unanswered set of questions—those relating to a possible military dimension of the Iranian nuclear program. Consistent with ElBaradei's statement, IAEA Director-General Yukiya Amano explained in a 2012 interview that the IAEA did not claim that "Iran [has] made a decision to obtain nuclear weapons." Notably, Tehran has implemented various restrictions on, and provided the IAEA with additional information about, its uranium enrichment program and heavy-water reactor program pursuant to the JCPOA. Iran and the IAEA agreed in August 2007 on a work plan to clarify the outstanding questions regarding Tehran's nuclear program, most of which concerned possible Iranian procurement activities and research directly applicable to nuclear weapons development. A December 2015 report to the IAEA Board of Governors from agency Director-General Amano contains the IAEA's "final assessment on the resolution" of these outstanding issues. Iran also has extensive programs to develop ballistic missiles and cruise missiles. (For more details on Iran's ballistic missile program, see CRS Report R42849, Iran's Ballistic Missile and Space Launch Programs , by Steven A. Hildreth.) The public controversy over Iran's nuclear program began in August 2002, when the National Council of Resistance on Iran (NCRI), an Iranian exile group, revealed information during a press conference (some of which later proved to be accurate) that Iran had built nuclear-related facilities at Natanz and Arak that it had not revealed to the IAEA. The United States had been aware of at least some of these activities, according to knowledgeable former officials. During the mid-1990s, Israel's intelligence services detected Iranian "efforts to develop a military nuclear industry," according to a 2004 Israeli Knesset committee report. Iran ratified the nuclear Nonproliferation Treaty (NPT) in 1970. States-parties to the treaty are obligated to conclude a comprehensive safeguards agreement with the IAEA; Tehran concluded such an agreement in 1974. In the case of nonnuclear-weapon states-parties to the treaty (of which Iran is one), such agreements are designed to enable the IAEA to detect the diversion of nuclear material from peaceful purposes to nuclear weapons uses, as well as to detect undeclared nuclear activities and material. As a practical matter, however, the IAEA's ability to inspect and monitor nuclear facilities, as well as obtain relevant information, pursuant to a comprehensive safeguards agreements is limited to facilities that have been declared by the government. Additional Protocols (see text box below) to IAEA safeguards agreements increase the agency's authority to inspect certain facilities and demand additional information from states-parties, thereby augmenting the agency's ability to investigate clandestine nuclear facilities and activities . The IAEA's statute requires the agency's Board of Governors to refer cases of noncompliance with safeguards agreements to the U.N. Security Council. Prior to the NCRI's revelations, the IAEA had expressed concerns that Iran had not been providing the agency with all relevant information about its nuclear programs, but the IAEA had never found Iran in violation of its safeguards agreement. In fall 2002, the IAEA began to investigate Iran's nuclear activities at Natanz and Arak; inspectors visited the sites the following February. During a June 2003 meeting, the IAEA board first expressed "concern" about Iran's past undeclared nuclear activities and urged Tehran to cooperate with the agency's investigation. The IAEA board's first resolution, which was adopted during a September 2003 meeting, called on Tehran to increase its cooperation with the agency's investigation and to suspend its uranium enrichment activities. (For more detail about Iran's nuclear organization, see Appendix B ). President Rouhani identified the Atomic Energy Organization of Iran (AEOI) as "the authority that was," prior to the June 2003 IAEA board meeting, "basically handling all political and technical issues concerning" the agency's investigation of Iran's nuclear program. Following that meeting, Iran's Supreme National Security Council created the Supreme Nuclear Committee, which was composed of officials from various agencies, including the AEOI and the ministries of defense, foreign affairs, and intelligence. After the IAEA board adopted its September 2003 resolution, the government placed Rouhani, who was the head of the Supreme National Security Council at the time, in charge of the negotiations concerning Iran's nuclear program. Rouhani explained the resulting nuclear decisionmaking process in 2011: Even though some people thought the nuclear team was operating with complete prerogatives, the facts were otherwise. The work procedure for every issue was that we first had to discuss the matter in the Supreme Nuclear Committee, then we took that result to the Meeting of Leaders, and finally we acted in accordance with the decision of the leaders. In October 2003, Iran concluded an agreement with France, Germany, and the United Kingdom, collectively known as the "E3," to suspend its enrichment activities, sign and implement an Additional Protocol to its IAEA safeguards agreement, and comply fully with the IAEA's investigation. As a result, the IAEA board decided to refrain from referring the matter to the U.N. Security Council, despite U.S. advocacy for such a referral. Statements from current and former Iranian officials indicate that, during fall 2003, Tehran feared that the United States might use Security Council referral as a means to undertake military action or other coercive measures against Iran. Rouhani argued in February 2005 that the United States would not take such action as long as Iran was cooperating with the IAEA and negotiating with the E3. After October 2003, Iran continued some of its enrichment-related activities, but Tehran and the E3 agreed in November 2004 to a more detailed suspension agreement. During negotiations between fall 2003 and summer 2005, both Iran and the E3 offered a number of proposals, although the two sides never reached agreement. The IAEA's investigation, as well as information Tehran provided after the October 2003 agreement, ultimately revealed that Iran had engaged in a variety of clandestine nuclear-related activities, some of which violated Iran's safeguards agreement. These activities included plutonium separation experiments, uranium enrichment and conversion experiments, and importing various uranium compounds. Current and former Iranian officials have depicted a government deeply divided during this time over diplomatic approaches regarding its nuclear program. For example, Seyed Hossein Mousavian, who was Iran's spokesperson during the government's 2003-2005 negotiations with France, Germany, and the United Kingdom (collectively known as the "E3"), explained that in 2003 "there were two schools of thought in Iran. One group advocated engagement with the West, while others were proponents of resistance." President Rouhani, who headed the 2003-2005 negotiations, explained during a July 2005 interview that certain parts of the Iranian government opposed the diplomatic track, adding that "[t]he problems included both disharmony and sabotage." Indeed, Rouhani later argued that Iran's Supreme National Security Council took charge of the diplomacy concerning the nuclear program because the Foreign Ministry was not able to be responsible for this task in a good way because some organizations did not pay sufficient attention to this ministry's decisions, especially since there had been disagreements for months between the Foreign Ministry and the Atomic Energy Organization. In a 2005 article, an Iranian Foreign Ministry official explained that the decision to delegate responsibility for the nuclear issue to the Supreme National Security Council was aimed at creating domestic consensus and preventing any possible discrepancies in the decision making process and its implementation at the national level. It was demonstrated in practice that this decision was crucial in preventing the friction between the government, parliament and all other relevant agencies. Iran resumed uranium conversion in August 2005 under the leadership of then-President Ahmadinejad, who had been elected two months earlier. On September 24, 2005, the IAEA Board of Governors adopted a resolution that, for the first time, found Iran to be in noncompliance with its IAEA safeguards agreement. The board, however, did not refer Iran to the Security Council, choosing instead to give Tehran additional time to comply with the board's demands. Iran announced in January 2006 that it would resume research and development on its centrifuges at Natanz. In response, the IAEA board adopted a resolution on February 4, 2006, that referred Iran's case to the Security Council. Two days later, Tehran announced that it would stop implementing its Additional Protocol. In March 2006, the U.N. Security Council President issued a statement, which was not legally binding, that called on Iran to "take the steps required" by the February IAEA board resolution. The council subsequently adopted six resolutions concerning Iran's nuclear program: 1696 (July 2006), 1737 (December 2006), 1747 (March 2007), 1803 (March 2008), 1835 (September 2008), and 1929 (June 2010). The second, third, fourth, and sixth resolutions imposed a variety of restrictions on Iran. In addition, these resolutions required Iran to cooperate fully with an ongoing IAEA investigation of its nuclear activities, suspend its uranium enrichment program, suspend its construction of a heavy-water reactor and related projects, and ratify the Additional Protocol to Iran's IAEA safeguards agreement. Resolution 1929 also required Tehran to refrain from "any activity related to ballistic missiles capable of delivering nuclear weapons" and to comply with a modified provision (called code 3.1) of Iran's subsidiary arrangement to its IAEA safeguards agreement. Beginning in June 2006, Iran later held multiple rounds of talks with China, France, Germany, Russia, the United Kingdom, and the United States, collectively known as the "P5+1," concerning various proposals for resolving the nuclear dispute. Saeed Jalili, then-head of Iran's Supreme National Security Council, conducted Iran's nuclear negotiations. Following his June 2013 election, Iranian President Rouhani delegated the "nuclear negotiations portfolio" to the Foreign Ministry, he explained in a September 2013 interview. The AEOI continued to be responsible for Tehran's negotiations with the IAEA. Supreme Leader Ayatollah Ali Khamene'i was the ultimate decisionmaker regarding Iran's diplomacy concerning the Joint Comprehensive Plan of Action. Then-Under Secretary of State for Political Affairs Wendy Sherman explained during a December 2013 hearing that Khamene'i "is the only one who really holds the nuclear file—makes the final decisions about whether Iran will reach a comprehensive agreement to forego much of what it has created in return for the economic relief it seeks." The Supreme Leader remained in charge of decisions regarding the nuclear program following Rouhani's 2013 election. Deputy Foreign Minister Seyed Abbas Araqchi explained in July 2016 that the nuclear issue was "under the senior management" of Khamene'i, adding that With regards the major foreign policy issues the more the decision making progresses and enters important levels the higher the level of engagement; it moves up from the ministry to the administration level and from the administration to the level of Supreme National Security Council and at the end to the supreme leader. Iran and the P5+1 met three times before concluding the Joint Plan of Action (JPA) on November 24, 2013. This agreement placed certain limitations on Iran's nuclear program and established an approach toward reaching a long-term comprehensive solution to international concerns regarding Iran's nuclear program. The two sides began implementing the JPA on January 20, 2014. The P5+1 and Iran reached a framework of a Joint Comprehensive Plan of Action (JCPOA) on April 2, 2015, and finalized the JCPOA on July 14, 2015. The parties began implementing the JCPOA on January 16, 2016. On that day, all of the previous Security Council resolutions' requirements were terminated. The NPT and U.N. Security Council Resolution 2231 compose the current legal framework governing Iran's nuclear program. On May 8, 2018, President Donald Trump announced that the United States would no longer participate in the JCPOA. The United States subsequently reimposed sanctions that had been suspended pursuant to the agreement. Other P5+1 countries immediately reiterated their support for the JCPOA and announced that they intend to fulfill their JCPOA commitments and protect their companies from the effects of any U.S.-imposed sanctions. President Rouhani has pledged to continue implementing the accord, provided Iran continues to receive the economic benefits of the agreement. (For more information about multilateral diplomacy concerning Iran's nuclear program, including the JCPOA's status, see Appendix C . For more information about the Trump administration's JCPOA policy, see Appendix D .) As noted, the IAEA investigation of Iran's nuclear program began in 2002. Iran and the IAEA agreed in August 2007 on a work plan to clarify the outstanding questions regarding Tehran's nuclear program. Most of these issues, which had contributed to suspicions that Iran had been pursuing a nuclear weapons program, were essentially resolved by June 2008.However, then-IAEA Director-General ElBaradei told the IAEA Board of Governors on June 2, 2008, that there is "one remaining major [unresolved] issue," which concerns questions regarding "possible military dimensions to Iran's nuclear programme." Iran and the IAEA subsequently held a series of discussions regarding these issues. The agency provided Iran with documents or, in some cases, descriptions of documents, which had been provided to the IAEA by several governments. The documents indicated that Iranian entities may have conducted studies related to nuclear weapons development. The subjects of these studies included uranium conversion, missile reentry vehicles for delivering nuclear warheads, and conventional explosives used in nuclear weapons. Iranian officials have claimed that the documents are not authentic, but ElBaradei told the IAEA board on June 17, 2009, that there was "enough in these alleged studies to create concern in the minds of our professional inspectors." Iranian officials acknowledged that some of the information in the documents is accurate, but they argued that the activities described were exclusively for nonnuclear purposes. Tehran has provided some relevant information about these matters to the IAEA, but ElBaradei reported in August 2009 that the government should "provide more substantive responses" to the IAEA, as well as "the opportunity to have detailed discussions with a view to moving forward on these issues, including granting the agency access to persons, information and locations identified in the documents." IAEA Director-General Amano issued a report to the IAEA board in November 2011 stating that Iran had not "engaged with the agency in any substantive way" on the alleged studies since August 2008. According to this report, which provided the most detailed account to date of the IAEA's evidence regarding Iran's suspected nuclear weapons-related activities, the agency has "credible" information that Iran has carried out activities "relevant to the development of a nuclear explosive device," including acquisition of "nuclear weapons development information and documentation," work to develop "an indigenous design of a nuclear weapon including the testing of components," efforts "to procure nuclear related and dual use equipment and materials by military related individuals and entities," and work to "develop undeclared pathways for the production of nuclear material." Although some of these activities have civilian applications, "others are specific to nuclear weapons," the report notes. Most of these activities were conducted before the end of 2003, though some may have continued. (See Appendix E and " Nuclear Weapon Development Capabilities " for more details.) The IAEA Board of Governors adopted a resolution on November 18, 2011, stating that "it is essential" for Iran and the IAEA "to intensify their dialogue aiming at the urgent resolution of all outstanding substantive issues." IAEA and Iranian officials met 10 times between January 2012 and May 2013 to discuss what the agency termed a "structured approach to the clarification of all outstanding issues related to Iran's nuclear programme." However, during an October 2013 meeting, IAEA officials and their Iranian counterparts decided to adopt a "new approach" to resolving these issues. Iran signed a joint statement with the IAEA on November 11, 2013, describing a "Framework for Cooperation." According to the statement, Iran and the IAEA agreed to "strengthen their cooperation and dialogue aimed at ensuring the exclusively peaceful nature of Iran's nuclear programme through the resolution of all outstanding issues that have not already been resolved by the IAEA." Tehran subsequently provided the IAEA with information about several of the outstanding issues and later agreed in May 2014 to provide information to the agency by August 25, 2014, about five additional issues, including alleged Iranian research on high explosives and "studies made and/or papers published in Iran in relation to neutron transport and associated modelling and calculations and their alleged application to compressed materials." Iran subsequently provided information about four of these issues. The July 2015 JCPOA states that Tehran was to "complete" a series of steps set out in an Iran-IAEA "Roadmap for Clarification of Past and Present Outstanding Issues." According to IAEA Director-General Amano, this road map, which the two sides concluded in July 2015, set out "a process" under the November 2013 JPA "to enable the Agency, with the cooperation of Iran, to make an assessment of issues relating to possible military dimensions to Iran's nuclear programme." According to a December 2, 2015, report to the IAEA Board of Governors from Amano, "[a]ll the activities contained in the road-map were implemented in accordance with the agreed schedule." The road map required Amano to present this report, which contains the agency's "final assessment on the resolution" of the aforementioned outstanding issues. In response, the board adopted a resolution on December 15, 2015, that notes Iran's cooperation with the road map and "further notes that this closes the Board's consideration" of the "outstanding issues regarding Iran's nuclear programme." Because the IAEA has verified that Iran has taken the steps required for Implementation Day to take effect, the board is no longer focused on either Iran's compliance with past Security Council resolutions or past issues concerning Iran's safeguards agreement. Instead, the board is focused on monitoring and verifying Iran's JCPOA implementation "in light of" United Nations Security Council Resolution 2231, which the council adopted on July 20, 2015. The December 2015 IAEA resolution requests the Director General to issue quarterly reports to the board regarding Iran's "implementation of its relevant commitments under the JCPOA for the full duration of those commitments." The Director General is also to report to the IAEA Board of Governors and the Security Council "at any time if the Director General has reasonable grounds to believe there is an issue of concern" regarding Tehran's compliance with its JCPOA or safeguards obligations. Parchin is an Iranian military site. As part of its investigation into "possible military dimensions" of Iran's nuclear program, the IAEA requested that Tehran respond to information which the agency obtained from unnamed governments regarding activity at the military site. Information provided to IAEA indicated that in 2000 "Iran constructed a large explosives containment vessel" at Parchin to conduct experiments related to the development of nuclear weapons, according to Amano's November 2011 report. The report did not say whether Iran actually built the vessel or conducted these experiments. IAEA inspectors visited the site twice in 2005, but they did not visit the location "believed to contain the building which houses the explosives chamber." The agency requested access to this latter building in February 2012, but Iran did not provide such access until September 2015 as part of the road map described above. At that time, IAEA officials conducted and supervised verification activities, including "visual observation and environmental sampling," but they "did not observe a chamber or any associated equipment inside the building." Iranian officials told their IAEA counterparts in October 2015 that the building in question "had always been used for the storage of chemical material for the production of explosives," but the "information available" to the IAEA, "does not support Iran's statements on the purpose of the building." Beginning in February 2012, Iran apparently undertook efforts to remove evidence of past nuclear-related activities at the site. These efforts, which included landscaping, refurbishing buildings, demolishing buildings, and removing and replacing external wall structures, "seriously undermined the Agency's ability to conduct effective verification," according to Amano's December 2, 2015, report. Iranian officials have implied that the government's refusal to allow IAEA post-2005 access to Parchin was due to Defense Ministry resistance. Fereydoun Abbasi-Davani, then-AEOI President, indicated in 2012 that allowing inspectors to the site was the Iranian military's decision. Rouhani in 2011 described a contentious internal debate regarding access to Parchin: In the area of Agency inspections and especially the inspections of military centers such as Parchin, this was debated for months inside the country and this issue was therefore raised in various meetings over the circumstances in which these inspections would take place. There was serious opposition to the Agency's request to inspect Parchin; the nation's domestic political climate was vigorously opposed to inspectors inspecting Parchin and military centers in general. For more information about the Parchin site, see Appendix E . Iran cooperated with the IAEA in other respects, albeit with varying consistency. The IAEA was (and still is) able to verify that Iran's declared nuclear facilities and materials have not been diverted for military purposes. Moreover, Tehran provided the agency with "information similar to that which Iran had previously provided pursuant to the Additional Protocol," ElBaradei reported to the IAEA board in February 2008, adding that this information clarified the agency's "knowledge about Iran's current declared nuclear programme." Iran, however, provided this information "on an ad hoc basis and not in a consistent and complete manner," the report said. Indeed, the IAEA requested in April 2008 that Iran provide "as a transparency measure, access to additional locations related ... to the manufacturing of centrifuges, research and development (R&D) on uranium enrichment, and uranium mining." Tehran provided such access pursuant to the 2013 JPA. ElBaradei's February 2008 report underscored the importance of full Iranian cooperation with the IAEA investigation, as well as Tehran's implementation of its Additional Protocol: Confidence in the exclusively peaceful nature of Iran's nuclear programme requires that the Agency be able to provide assurances not only regarding declared nuclear material, but, equally importantly, regarding the absence of undeclared nuclear material and activities in Iran.... Although Iran has provided some additional detailed information about its current activities on an ad hoc basis, the Agency will not be in a position to make progress towards providing credible assurances about the absence of undeclared nuclear material and activities in Iran before reaching some clarity about the nature of the alleged studies, and without implementation of the Additional Protocol. The IAEA also asked Iran to "reconsider" its March 2007 decision to stop complying with a portion of the subsidiary arrangements for its IAEA safeguards agreement. That provision (called code 3.1), to which Iran agreed in February 2003, requires Tehran to provide design information for new nuclear facilities "as soon as the decision to construct, or to authorize construction, of such a facility has been taken, whichever is earlier." Previously, Iran was required to provide design information for a new facility 180 days before introducing nuclear material into it. Iran invoked the March 2007 decision when it withheld from the IAEA until September 2009 "preliminary design information" for the planned Darkhovin reactor; the agency first requested the information in December 2007. Although Iran provided the agency with preliminary design information about the Darkhovin reactor in a September 22, 2009, letter, the IAEA requested Tehran to "provide additional clarifications" of the information. Amano reported in September 2010 that Iran had "provided only limited design information with respect to" the reactor. Tehran also refused to provide updated design information for the Arak reactor—a decision which, according to a May 2013 report from Amano, had "an adverse impact on the Agency's ability to effectively verify the design of the facility." As part of the JPA, Iran submitted this information to the IAEA on February 12, 2014. Pursuant to the JCPOA, Iran has committed to redesign and rebuild the Arak reactor based on a design agreed to by the P5+1 so that it will not produce weapons-grade plutonium. Iran has rendered the reactor's original core inoperable. Iran had also refused to allow IAEA officials to conduct an inspection of the Arak reactor in order to verify Iranian-provided design information. ElBaradei argued in a June 2009 report to the IAEA board that this continued refusal "could adversely impact the Agency's ability to carry out effective safeguards at that facility," adding that satellite imagery was insufficient because Iran has completed the "containment structure over the reactor building, and the roofing for the other buildings on the site." However, IAEA inspectors visited the reactor facility in August 2009 to verify design information, according to ElBaradei's report issued the same month. IAEA inspectors had last visited the reactor in August 2008. Inspectors have visited the facility several more times, according to reports from Amano. In addition, Iran failed to notify the IAEA until September 2009 that it was constructing a uranium enrichment facility, called the Fordow Fuel Enrichment Plant, near the city of Qom. Iran revealed in September 2009 that it had been constructing the facility and provided some details about it to the IAEA in a September 21, 2009, letter. Four days after the IAEA received the letter, British, French, and U.S. officials revealed that they had previously developed intelligence on the facility. The three governments provided a detailed intelligence briefing to the IAEA after the agency received Iran's letter. U.S. officials have said that, despite its letter to the agency, Iran intended for the facility to be kept secret. Tehran placed the facility under IAEA safeguards after its September 2009 letter. (For more details, see the " Fordow Enrichment Facility " section below.) Pursuant to the JCPOA, Iran has begun to convert its Fordow enrichment facility into "a nuclear, physics, and technology centre" in which no nuclear material will be present. In a letter published on October 1, 2009, the IAEA asked Iran to provide additional information about the facility, including "further information with respect to the name and location of the pilot enrichment facility, the current status of its construction and plans for the introduction of nuclear material into the facility." The letter also requested that Tehran provide IAEA inspectors with access to the facility "as soon as possible." IAEA officials inspected the facility and met with Iranian officials in late October 2009. According to a November 2009 report from ElBaradei to the IAEA board, Tehran "provided access to all areas of the facility," which "corresponded with the design information provided by Iran" a week before the visit. IAEA officials have since conducted regular inspections of the facility. Although Iran provided additional design information about the facility to the IAEA, the agency still had questions about the facility's "purpose and chronology" and wished to interview other Iranian officials and review additional documentation, according to ElBaradei's report. Amano reported in May 2012 that Iran had provided the IAEA with some requested information regarding the Fordow construction decision, but the agency still wanted more information from Tehran. Tehran, according to Amano's November 2015 report, has not yet provided all of this information. Subsequent reports from Amano have not addressed the issue. The IAEA has also requested additional information about Iran's production of heavy water. As noted, Iran is constructing a heavy-water nuclear reactor. ElBaradei's November 2009 report states that, during an inspection of Iran's uranium conversion facility the previous month, IAEA inspectors "observed 600 50-litre drums said by Iran to contain heavy water." The inspectors visited the facility to verify updated design information submitted by Iran in August 2009. The inspectors observed the drums after gaining access to an area of the facility that agency inspectors had not previously visited. Tehran told the IAEA that the water originated in Iran and permitted agency inspectors to count the number of drums and weigh a "small number of randomly selected drums." For a time, Tehran did not permit the agency to take samples of the heavy water, but the government did allow such access in February 2014. Similarly, Iran for some time did not grant repeated IAEA requests for "further access" to the country's heavy-water production plant since agency inspectors visited the facility in August 2011. However, Iran granted such access in December 2013. The IAEA apparently resolved a discrepancy discovered during an August 2011 inspection of an Iranian research laboratory that had been used to conduct uranium conversion experiments. IAEA measurements revealed that Iran had overstated the amount of material in the facility, described in Amano's November 2011 report as "natural uranium metal and process waste," by almost 20 kilograms. Iran and the IAEA appear to have resolved the issue in 2013. Some nongovernmental experts and former U.S. officials have argued that, rather than producing fissile material for nuclear weapons indigenously, Iran could obtain such material from foreign sources. A November 2007 National Intelligence Estimate (NIE) states that the intelligence community "cannot rule out that Iran has acquired from abroad—or will acquire in the future—a nuclear weapon or enough fissile material for a weapon." A senior intelligence official characterized such acquisition as "an inherent option" for Iran. However, Tehran's potential ability to produce its own fissile material is a greater cause of concern; the official explained that "getting bits and pieces of fissile material from overseas is not going to be sufficient" to produce a nuclear arsenal. As noted, uranium enrichment facilities can produce highly enriched uranium (HEU), which is one of the two types of fissile material used in nuclear weapons. The other type is plutonium, which is separated from spent nuclear reactor fuel. According to a November 14, 2013, IAEA report, Iran had generally stopped expanding its enrichment and heavy-water reactor programs during the negotiations leading up to the JPA, which the parties finalized later that month. That agreement essentially froze most aspects of Iran's nuclear program to allow time to negotiate the July 2015 JCPOA. When the JPA went into effect in January 2014, Iran had enough uranium hexafluoride containing up to 5% uranium-235 to yield—if further enriched—weapons-grade HEU for as many as eight nuclear weapons. If it had been further enriched, the total amount of Iranian uranium hexafluoride containing 20% uranium-235 would have been sufficient for a nuclear weapon. Pursuant to the JCPOA, Iran has restricted and/or dismantled various portions of its nuclear program. Iran currently lacks enough low-enriched uranium hexafluoride to produce a nuclear weapon. Since the JCPOA's Implementation Day, Iran has imported items for its nuclear program via a JCPOA-established "procurement channel," which, according to the agreement, is to last for a duration of 10 years. A Procurement Working Group, which is part of the JCPOA-established Joint Commission, reviews proposals for nuclear-related transfers to Iran. The working group provides its recommendations to the UN Security Council, which approves any exports. The JCPOA requires Iran to provide the IAEA with "access to the locations of intended use of all items, materials, equipment, goods and technology" listed in the NSG's "Guidelines for Nuclear Transfers." Tehran is also to permit exporting governments to "verify the end-use of all items, materials, equipment, goods and technology" listed in the NSG's "Guidelines for Transfers of Nuclear-Related Dual-Use Equipment, Materials, Software, and Related Technology." According to a December 6, 2018, report by U.N. Secretary-General António Guterres, the Security Council had received 42 nuclear-related export proposals since Implementation Day; the council approved 28 of those proposals and disapproved four. Nine proposals were withdrawn by the submitting states and one was under review. Iran has used three centrifuge facilities to enrich uranium: a pilot centrifuge facility and a larger commercial facility, both located at Natanz, and the Fordow centrifuge facility located near the city of Qom. Iran also has a variety of facilities and workshops involved in the production of centrifuges and related components. (See Appendix F and CRS Report R42443, Israel: Possible Military Strike Against Iran's Nuclear Facilities , coordinated by Jim Zanotti.) During a July 31 , 2015, press briefing about possible Iranian undeclared nuclear facilities, U.S. Secretary of Energy Ernest Moniz stated that "we feel pretty confident that we know their current configuration." This facility was to have held approximately 50,000 centrifuges. Former Vice President Gholamreza Aghazadeh, who also headed the AEOI until July 2009, explained in February 2009 that Iran intended to install all of the centrifuges by 2015. Iran began enriching uranium in the facility after mid-April 2007; as of November 5, 2013, the facility had produced 10,357 kilograms of low-enriched uranium hexafluoride containing up to 5% uranium-235. This quantity of LEU, if it had been further enriched, would have yielded enough weapons-grade HEU for as many as eight nuclear weapons. As of October 31, 2015, the facility had produced 15,525 kilograms of uranium hexafluoride containing up to 5% uranium-235. However, Iran had only approximately 8,305 kilograms of this material because the rest had been converted into various other chemical forms. Individual centrifuges are linked together in cascades; each cascade in the commercial facility contained either 164 or 174 centrifuges. As of May 17, 2015, Tehran had installed about 15,400 first generation (IR-1) centrifuges, approximately 9,150 of which were enriching uranium. Iran had also installed about 1,000 centrifuges of greater efficiency, called IR-2m centrifuges, in the facility. The IR-2m centrifuges were not enriching uranium. Amano reported in February 2017 that, pursuant to its JCPOA commitments, Iran had 5,060 IR-1 centrifuges installed in the facility and had removed all other centrifuges. Iran had been producing enriched uranium hexafluoride continuing no more than 3.67% uranium-235 but also shipped out most of its LEU to Russia on December 28, 2015, to reduce its stockpile to the required levels. Iran's total stockpile of this material has not exceeded 300 kilograms since Tehran began implementing its JCPOA commitments. Iran began enriching uranium up to 20% uranium-235 in the Natanz pilot facility in February 2010. Iranian officials stated that this enriched uranium was to serve as fuel in Iran's Tehran Research Reactor (TRR), as well as future such research reactors. Construction of the U.S.-supplied TRR began in 1960, and it went critical in 1967. Initially fueled by U.S.-supplied HEU, the reactor was converted to use LEU fuel in 1994 after Argentina agreed to supply the reactor with such fuel in 1987. Fereydun Abbasi-Davani, then-President of the Atomic Energy Organization of Iran, stated in a 2012 interview that once Iran had "enough" uranium enriched to this level, the country would use its enrichment facilities to produce enriched uranium containing 3.5% uranium-235. Iran has tested several types of more-advanced centrifuges in the pilot facility; these centrifuges could increase the other enrichment facilities' capacity. Tehran has altered this facility to comply with the JCPOA's limits on Iranian centrifuge research and development. Iran's development of new centrifuges has apparently been less successful than development of the IR-1 centrifuge; past estimates from Iranian officials regarding the deployment of more-advanced centrifuges have been excessively optimistic. According to a 2012 report from a U.N. panel of experts, the advanced centrifuge program's lack of success may have been "the result of sanctions limiting" Tehran's "ability to procure items necessary for its centrifuge programme," as well as "[o]ther variables, including design and manufacturing limitations, or a shortage of other necessary materials." The JCPOA contains a detailed description of centrifuge research and development (R&D) that Iran is permitted to conduct under the agreement. Iran is to conduct centrifuge R&D with uranium only at the Natanz pilot facility and will conduct mechanical testing of centrifuges only at the pilot facility and the Tehran Research Centre. Iran submitted an "enrichment R&D plan" to the IAEA in January 2016 as part of Tehran's initial declaration for its Additional Protocol. Iranian adherence to that plan is a JCPOA requirement. In December 2011, Iran began enriching uranium up to 20% uranium-235 in the Fordow Fuel Enrichment Plant, according to IAEA reports. As of November 1, 2013, Iran was feeding uranium hexafluoride into four cascades (696 centrifuges) of IR-1 centrifuges and had installed a total of 2,710 IR-1 centrifuges in the facility. Tehran had planned to install a total of 16 cascades containing approximately 3,000 centrifuges. Tehran told the IAEA that the facility would be configured to produce both uranium enriched to 5% uranium-235 and 20% uranium-235. Iran also told the IAEA that "the facility could be reconfigured to contain centrifuges of more advanced types should Iran take a decision to use such centrifuges in the future." Iran agreed under the JCPOA to convert the facility into "a nuclear, physics, and technology centre." The facility will not contain any nuclear material. Pursuant to this commitment, Iran has decreased the number of IR-1 centrifuges to 1,044, and it has removed all nuclear material from the facility. In addition, Iran has modified two cascades "for the production of stable isotopes" for medical and industrial uses. As noted, Iran revealed in September 2009 that it had been constructing the facility. That same month, Tehran provided some details about the facility to the IAEA. The United States had been "observing and analyzing the facility for several years," according to September 25, 2009, Obama Administration talking points, which added that "there was an accumulation of evidence" earlier in 2009 that the facility was intended for enriching uranium. Some of this evidence apparently indicated that "Iran was installing the infrastructure required for centrifuges earlier" in 2009. U.S. officials have not said exactly when Iran began work on the facility, which is "located in an underground tunnel complex on the grounds of an Islamic Revolutionary Guard Corps" base near the Iranian city of Qom. Nevertheless, the Atomic Energy Organization of Iran (AEOI), rather than the Iranian military, is responsible for the development and management of the facility, according to the September 2009 U.S. talking points described above. According to a November 2009 report from then-IAEA Director-General ElBaradei, Iran informed the IAEA that construction on the site began in the second half of 2007. However, citing information in its possession that appears to contradict Tehran's claim, the IAEA asked Iran to provide more information about the facility's chronology. U.S. officials suggested that the facility may have been part of a nuclear weapons program. President Obama stated on September 25, 2009, that "the size and configuration of this facility is inconsistent with a peaceful program." But the Administration's talking points were somewhat more vague, stating that the facility "is too small to be viable for production of fuel for a nuclear power reactor," although it "could be used" for centrifuge research and development or "configured to produce weapons-grade uranium." The facility "would be capable of producing approximately one weapon's worth" of HEU per year, according to the talking points. Iran's failure to inform the IAEA of the Fordow plant's existence until well after Tehran had begun constructing it raised concerns that the country may have had other covert nuclear facilities. A November 2009 IAEA Board of Governors resolution stated that Iran's declaration of the Fordow facility "reduces the level of confidence in the absence of other nuclear facilities and gives rise to questions about whether there are any other [undeclared] nuclear facilities under construction in Iran." Furthermore, then-UK Foreign Office Minister Alistair Burt told Parliament in February 2012 that the Fordow facility "which Iran initially kept secret from the IAEA, also raises our concerns that there may also be other, undeclared sites in Iran that could be engaged in work" related to nuclear weapons. Tehran's shifting explanations regarding the facility's purpose also raised concerns that Iran would, in the future, use the facility to produce fissile material for nuclear weapons. Iran's 2009 letter to the IAEA described the Fordow facility as a "new pilot fuel enrichment plant" that would produce uranium enriched to no higher than 5% uranium-235. Tehran subsequently changed the plant's stated purpose several times. For example, Tehran, as noted, later told the IAEA that the facility would be configured to produce both uranium enriched to 5% uranium-235 and 20% uranium-235. Apparently suggesting that Iran might later produce uranium containing higher levels of uranium-235, a U.S. official told the IAEA Board of Governors on March 8, 2012, that "[w]e cannot help but wonder ... whether Iran has finally informed us of the ultimate purpose of this facility." For its part, Iran has asserted that the facility is for peaceful purposes and that the government has acted in accordance with its international obligations. As noted, Tehran argued that it was producing enriched uranium containing up to 20% uranium-235 for use as fuel in research reactors, to be used to produce isotopes for medical purposes. Regarding the facility's secret nature, Iranian officials argued that Tehran was not previously obligated to disclose it to the IAEA and stated on several occasions that the facility was concealed to protect it from military attacks. Iran told the IAEA in 2009 that the Fordow facility was to serve as a "contingency enrichment plant, so that the enrichment activities shall not be suspended in the case of any military attack." The Natanz commercial facility "was among the targets threatened with military attacks," Iran explained. Iranian officials stated during a June 2012 meeting with the P5+1 that the Fordow facility is "not a military base" and is "not located on a military base." As noted, Iran argued that it was producing LEU containing nearly 20% uranium-235 for use in research reactors; as of January 20, 2014, when the JPA went into effect, Tehran had used the Natanz pilot facility and the Fordow facility to produce a total of 447.8 kilograms of uranium hexafluoride containing up to 20% uranium-235. Iran's production of uranium enriched to this level has caused concern because such production requires approximately 90% of the effort necessary to produce weapons-grade HEU, which contains about 90% uranium-235. If further enriched, this amount of material would have been sufficient for a nuclear weapon. Iran would need approximately 215 kilograms of uranium hexafluoride containing 20% uranium-235 to produce approximately 27.8 kilograms of uranium containing 90% uranium-235—a sufficient amount of weapons-grade HEU for a nuclear weapon. This is a conservative estimate; the specific characteristics of Iran's enrichment facilities may necessitate using more than 215 kilograms of such material. Then-Director of National Intelligence James Clapper suggested during a February 16, 2012, Senate Armed Services Committee hearing that "a number of factors" could impede Tehran's ability to produce weapons-grade HEU from uranium enriched to 20% uranium-235. As of January 20, 2014, approximately 160 kilograms of the LEU described above was in the form of uranium hexafluoride and, therefore, available to be further enriched in the near term. Since that date, Iran has either converted much of that material for use as fuel in the Tehran Research Reactor or prepared it for that purpose. Iran diluted the rest of that stockpile so that it contained no more than 5% uranium-235. AEOI spokesperson Behrouz Kamalvandi said in February 2014 that Iran had "the necessary reservoirs of fuel for 5 years for the Tehran research reactor." Iranian officials indicated in the past that Tehran intended to construct 10 additional centrifuge plants—a goal that many analysts argued was virtually unachievable. Then- Atomic Energy Organization President Ali Akbar Salehi stated in 2009 that Iran is investigating locations for the sites. (Salehi was president of the organization from 2009 to 2010; he became president again in August 2013.) In 2012, then-Atomic Energy Organization President Abbasi argued that "mastering" centrifuge enrichment technology would enable Iran to "develop [centrifuge] sites in various locations to avoid any threat by foreign enemies." According to the JCPOA, Iran is to enrich uranium only at the Natanz commercial facility for 15 years. Expiration of the JCPOA enrichment restrictions will be "followed by gradual evolution, at a reasonable pace" of Iran's enrichment program. According to the JCPOA, Iran's centrifuge-testing program may proceed under strict limits, which will begin to ease approximately eight years after the beginning of the agreement's implementation. An AEOI spokesperson stated in January 2016 that Iran's nuclear program "will begin to accelerate from the 13 th or 14 th year onwards," adding that Tehran plans to increase its enrichment capacity by approximately "20-fold" by the end of the 15 th year. Iran plans to produce enough enriched uranium to fuel five or six nuclear reactors, Deputy Foreign Minister Araqchi stated in August 2015. AEOI spokesperson Kamalvandi explained in June 2018 that Iran would begin the process of "manufacturing and assembly of centrifuge rotors," which are critical components of such machines. Iran "will begin building a centrifuge rotor plant," he noted. In addition, Salehi announced in June that Iran has completed building a centrifuge assembly center in the Natanz facility; Tehran had not previously disclosed this facility publicly. The facility's completion "does not mean that we are going to produce these centrifuges now," Salehi said in September 2018, adding that the facility provides Iran with the capability to mass-produce such centrifuges, should the government decide to do so. A senior U.S. intelligence official said in 2007 that a country needs to be able to "operate large numbers of centrifuges for long periods of time with very small failure rates" in order to be able to "make industrial quantities of enriched uranium." Iran's record indicates that the country has not always met this standard. The 2007 National Intelligence Estimate stated that Iran still faced "significant technical problems operating" its centrifuges. Although a 2008 report to Congress submitted by the Deputy Director for National Intelligence described the amount of LEU that Iran produced in 2008 as a "significant improvement" over the amount it had produced during the previous year, data from an August 2015 Institute for Science and International Security report indicate that the average per-centrifuge performance at that facility peaked in 2010 and subsequently fluctuated. The extent to which Iran's progress is sustainable is open to question. Former Pakistani nuclear official Abdul Qadeer Khan described Pakistan's first-generation centrifuges as "unsuccessful" in a 1998 interview. Furthermore, Mark Fitzpatrick of the International Institute for Strategic Studies observed that "[i]t can be years before it is clear whether an enrichment programme is working well," observing that centrifuges at a Japanese enrichment facility "started to crash seven years after installation." And, as noted, Iran has struggled to develop and deploy more-advanced centrifuges. Nevertheless, historical experience indicates that sustained operation of gas centrifuges appears to be a manageable task for governments with even modest technical capabilities. According to a U.S. Nuclear Regulatory Commission document, some centrifuges of simple design "have operated 30 years with a failure rate of less than one percent." (See also " Effects of Sanctions and Sabotage on Iran's Enrichment Program .") As noted, uranium conversion is a process whereby uranium ore concentrate is converted into several compounds, including uranium hexafluoride—the feedstock for Iran's centrifuges. Iran produced approximately 541 metric tons of uranium hexafluoride between March 2004 and August 10, 2009, using both imported uranium ore concentrate and domestically produced uranium ore concentrate. Iran has not produced any uranium hexafluoride since August 2009, according to IAEA reports, although Tehran has transferred domestically produced uranium ore concentrate to the uranium conversion facility. The 2012 U.N. Panel of Experts report concluded that, based on data from Amano's February 2012 report, Iran had "an ample supply of uranium hexafluoride to maintain current levels of enrichment for the foreseeable future." On June 27, 2018, Iran's official news agency announced that Iran has resumed operations at the conversion facility. According to a report from the Director of National Intelligence to Congress covering 2011, Iran had "almost exhausted" its supply of imported uranium ore concentrate. Tehran apparently did not import any more such material prior to December 2015. According to the 2012 U.N. Panel of Experts report, "a number" of governments believed that Tehran was "seeking new sources of uranium ore to supply its enrichment efforts"; the report added that "the Panel is not aware of any confirmed cases of actual transfers." British Foreign and Commonwealth Office official Tobias Ellwood informed Parliament in June 2015 that the British government was "not aware of" any recent reports that Iran had attempted to purchase foreign uranium. Former State Department official Richard Nephew wrote in September 2015 that there had "not been any verified transfer of uranium to Iran aside from fuel for the Bushehr power reactor." In late December 2015, Iran imported between 200 and 220 metric tons of uranium ore concentrate in exchange for LEU that Iran shipped to Russia in order to reduce its stockpile to JCPOA-required levels. The IAEA verified Iran's receipt in February 2017 of approximately 125 metric tons of uranium ore concentrate. During March 2017, Iranian officials stated that the country had imported between 382 and 384 metric tons of this material since concluding the JCPOA. The imported uranium ore concentrate is to serve as fuel for the Bushehr reactors, according to Iranian officials. Prior to 2009, Tehran apparently improved its ability to produce centrifuge feedstock of sufficient purity for light-water reactor fuel; information in a 2010 IAEA report indicated that Iran was purifying its centrifuge feedstock. Whether Iran is currently able to produce feedstock pure enough for weapons-grade HEU is unclear, however. Iran acknowledged to the IAEA in 2003 that it had conducted plutonium-separation experiments—an admission that contributed to suspicions that Iran could have a program to produce plutonium for nuclear weapons. The IAEA, however, continued to investigate the matter; then-IAEA Director-General ElBaradei reported in August 2007 that the agency had resolved its questions about Iran's plutonium activities. As noted above, Iran has said that it does not plan to engage in reprocessing, and IAEA Director-General Amano's November 2011 report described an "absence of any indicators that Iran is currently considering reprocessing irradiated nuclear fuel to extract plutonium." Amano's November 2015 report states that the agency could "confirm that there are no ongoing reprocessing related activities" at the Iranian facilities to which the agency has access. The JCPOA prohibits Iran from reprocessing spent reactor fuel, except to produce "radio-isotopes for medical and peaceful industrial purposes." The JCPOA text states that Iran "does not intend" to engage in reprocessing after the 15-year period expires and specifies Iran's intention to "ship out all spent fuel for all future and present nuclear power and research reactors, for further treatment or disposition as provided for in relevant contracts to be concluded consistent with national laws with the recipient party." According to the IAEA, Iran has adhered to this requirement. Iran says that its reactor under construction at Arak is intended for the production of medical isotopes and various other purposes. According to a 2008 presentation by Ambassador Soltanieh, the reactor, which was originally designed to be moderated by heavy water, is to substitute for the "outdated" Tehran Research Reactor (TRR), which has been in operation since 1967. As noted, Iran subsequently decided to refuel the TRR. According to a 2012 AEOI report, the reactor has several objectives: a suitable replacement for the aging Tehran Research Reactor using local engineers and scientist [sic] with the least dependency to foreign countries; medical, industrial and research radioisotope production of [sic] the country; performing research in the fields of neutron physics, reactor chemistry, thermal-hydraulics, and health physics; obtaining technological and scientific experience in design and construction of nuclear reactors using local experts within the country; training of specialists in the nuclear field; and enhancing the technological levels of the local industries in design and manufacturing of various components such as reactor vessels, heat exchangers, pumps, etc. using nuclear standards. Iran told the IAEA in 2012 that the reactor was scheduled to begin operating during the second half of 2013. The project was about 75% complete as of July 2011. Iran suspended several aspects of the reactor's construction pursuant to the 2013 Joint Plan of Action. The originally designed Arak reactor was a proliferation concern because its spent fuel would have contained plutonium better suited for nuclear weapons than the plutonium produced by light-water moderated reactors, such as the TRR and Bushehr reactor. The original Arak reactor, if it had been completed, could have produced enough plutonium for between one and two nuclear weapons per year. In addition, Iran would have been able to operate the reactor with natural uranium and, therefore, would not have been dependent on supplies of enriched uranium. The JCPOA requires Tehran to render the Arak reactor's original core inoperable. Iran has met this requirement. The agreement also commits Tehran to redesign and rebuild the Arak reactor based on a design agreed to by the P5+1 so that the reactor will not produce weapons-grade plutonium. Tehran is "trying to complete the project in five years," an AEOI spokesperson said in January 2016. AEOI President Salehi stated in September 2016 that China will supply the reactor's first fuel load "in the next five-year time." Iran will subsequently produce the reactor fuel, he said. Iran is to export the spent fuel from this reactor and all other nuclear reactors. In addition, the JCPOA requires Iran to refrain from building heavy-water-moderated reactors for 15 years, and Tehran has pledged to refrain from constructing any such reactors indefinitely. According to IAEA reports and Iranian officials, Iran began to operate its heavy-water production plant located near Arak in August 2006. Reports from Amano since the start of JCPOA implementation indicate that the plant, which is to produce heavy water for the reactor and deuterated solvents, is operating. Pursuant to the JCPOA, Tehran has committed to refrain from accumulating heavy water "beyond Iran's needs." Iran is to "sell any remaining heavy water on the international market for 15 years." According to the agreement, these "needs" are 130 metric tons of "nuclear grade heavy water or its equivalent in different enrichments" prior to commissioning the redesigned Arak reactor and 90 metric tons after the reactor is commissioned. Iran's stock of heavy water has exceeded 130 metric tons on two occasions since the JCPOA began implementation. On February 17, 2016, the IAEA verified that Tehran's heavy-water stock had exceeded 130 metric tons; on November 8, 2016, the IAEA verified that Iran's stock of heavy water had again exceeded the JCPOA limit. Iran resolved the issue on both occasions by exporting the excess heavy water. Tehran sent this material to Russia and the United States, shipping at least some of it via Oman. Iran told the IAEA on June 18, 2017, that it had transferred 19.1 metric tons of heavy water to a destination outside the country. According to an April 2018 State Department report covering 2017, "[m]ost Iranian excess heavy water has been sold and delivered to international buyers; the remainder is awaiting sale and is stored in a location outside Iran, under IAEA seal, though it remains Iranian property." Tehran has continued to ship heavy water outside Iran, according to the three most recent IAEA reports. the IAEA reported in August and November 2018. The IAEA verified on February 16, 2019, that Iran had 122.8 metric tons of heavy water. Iran is also operating a 1,000-megawatt nuclear power reactor, moderated by light water, near the city of Bushehr. The original German contractor, which began constructing the reactor in 1975, abandoned the project following Iran's 1979 revolution. Russia agreed in 1995 to complete the reactor, but the project subsequently encountered repeated delays; both Russian and Iranian officials attributed those delays to technical issues. In February 2005, Moscow and Tehran concluded an agreement stating that Russia would supply fuel for the reactor for 10 years. Atomstroyexport, a subsidiary of Rosatom, the Russian company, sent the first shipment of LEU fuel to Iran on December 16, 2007, and the reactor received the last shipment near the end of January 2008. The fuel, which is under IAEA seal, will contain no more than 3.62% uranium-235, according to an Atomstroyexport spokesperson. An August 2014 IAEA inspection revealed that the reactor "was operating at 100% of its nominal power." Before 2002, the United States had previously urged Moscow to end the project, citing concerns that it could aid an Iranian nuclear weapons program by providing the country with access to nuclear technology and expertise. However, U.S. officials said in 2002 that Washington would drop these public objections if Russia took steps to mitigate the project's proliferation risks. The 2005 deal requires Iran to return the spent nuclear fuel to Russia. This measure is designed to ensure that Tehran will not separate plutonium from the spent fuel. Moscow argues that the reactor will not pose a proliferation risk because it will operate under IAEA safeguards. It is worth noting that light-water reactors are generally regarded as more proliferation-resistant than other types of reactors. Although the U.N. Security Council resolutions restricted the supply of nuclear-related goods to Iran, they did permit the export of nuclear equipment and fuel related to light-water reactors. Experts have expressed strong doubts regarding Iran's ability to produce fuel for the reactor. According to a July 2014 Iranian government report, Russia and Iran may renew the fuel supply agreement, but they are also "engaged in negotiations ... to engage in cooperative arrangements for the domestic manufacturing of fuel for the facility after the expiration of the current contract." According to an interview published in April 2017, AEOI Deputy Director Pezhman Rahimian stated that the two governments had almost completed a "road map" for such manufacturing. AEOI President Salehi expressed "hope" in September 2018 that a second power reactor at the Bushehr plant "will become operational in the next six years." A Rosatom official told the IAEA General Conference in September 2018 that "[p]ractical work to build the second and third" Bushehr power plant units "has begun." Salehi told the same conference that "the first concrete pouring" for the second Bushehr reactor "has been planned for the third quarter of 2019." Iran and Russia signed a contract in November 2014 for the construction of two additional light-water nuclear power reactors in Bushehr, according to Rosatom, the Russian company. The project's construction began in September 2016 and is expected to take 10 years to complete. Iran was "negotiating with China for building two 100 megawatt power plants," Salehi stated in a July 2015 speech. Iran informed the IAEA in an October 2017 letter that Tehran had decided to "design and construct a critical facility (Light Water Critical Reactor) … for research purposes in near future." Iran "provided preliminary design information for the facility," which indicates that the reactor fuel is to contain "up to 3.67%" uranium-235. Iran intended its fuel manufacturing plant to produce fuel for the Arak and Darkhovin reactors. The plant started the process of producing fuel for the pre-JCPOA Arak reactor. Iran's Fuel Plate Fabrication Plant has produced fuel for the Tehran Research Reactor. Iran has a uranium mill and a uranium mine located at a site called Bandar Abbas, which is sometimes referred to as Gchine. Iran also has a uranium mine at a site called Saghand and an associated uranium mill called the Ardakan Yellowcake Production Plant. Salehi stated in a January 30, 2019, interview that Tehran plans to construct several more such mills. Iranian officials acknowledge that the country's uranium deposits are insufficient for its planned nuclear power program. These reserves are sufficient, however, to produce 250-300 nuclear weapons, according to a past U.S. estimate. Salehi indicated in February 2019 that Iran continues to explore for uranium. A number of governments employed sanctions and, apparently, sabotage to impede Iran's nuclear program. Iran has tried to improve its capabilities to produce materials and components for its centrifuge program, according to former IAEA Deputy Director General Olli Heinonen. Some Iranian officials have claimed that the country can manufacture centrifuges on its own. For example, then-Iranian Ambassador to the IAEA Ali Asghar Soltanieh said in 2012 that Iran "has 'fully mastered' the nuclear energy technology and can produce all the 90 pieces of a centrifuge machine on its own and without foreign assistance." However, a 2014 U.N. Panel of Experts report observed that the "quality of such [Iranian-produced] equipment is not known." Furthermore, other Iranian officials have suggested that Tehran is not yet able to produce all of the necessary centrifuge components. Then-President of Iran's Atomic Energy Organization Abbasi stated during a 2012 television broadcast that "Iran could not claim that it did not need other countries" for its enrichment program, adding that "domestic production of all items was not economically viable." AEOI Director Salehi stated in 2014 that Iran was purchasing some items for its nuclear program "from some developing and growing Eastern countries." Moreover, then-Principal Deputy Assistant Secretary of State for International Security and Nonproliferation Vann Van Diepen said that Iran in 2014 was still attempting to "procure items" for the nuclear program. Nevertheless, according to the 2014 Panel of Experts report, several governments told the panel that, since mid-2013, there had been a "been a decrease in the number of detected [Iranian] attempts ... to procure items for prohibited programmes, and related seizures." A 2015 Panel of Experts report states that the panel had not "identified cases of procurement for activities prohibited" by Security Council resolutions in force at the time. No governments reported any such cases, the report adds. According to various sources, international sanctions made it difficult for Iran to obtain components and materials for its centrifuge program. For example, the U.N. Panel of Experts 2011 report stated that "sanctions are constraining Iran's procurement of items related to prohibited nuclear and ballistic missile activity and thus slowing development of these programmes." Similarly, the 2012 U.N. Panel of Experts report observed that "[s]anctions are slowing the procurement by the Islamic Republic of Iran of some critical items required for its prohibited nuclear programme." A June 2013 report suggested that this condition still existed, arguing that "Iran's reliance on procurement abroad continues to provide the international community with opportunities to limit Iran's ability to maintain and expand certain activities." Then-UK Foreign Secretary William Hague wrote in 2013 that "[w]e judge that sanctions have been effective in slowing the nuclear programme to some degree." U.S. officials have argued that the sanctions have impeded Iran's ability to acquire technology for its nuclear programs. Then-State Department Special Advisor for Nonproliferation and Arms Control Robert Einhorn told a Washington audience in 2011 that "[w]e believe Iran has had difficulty in acquiring some key technologies and we judge this has had an effect of slowing some of its programs." Similarly, then-National Security Adviser Tom Donilon argued in 2011 that "[s]anctions and export control efforts have made it more difficult and costly for Iran to acquire key materials and equipment for its enrichment program, including items that Iran can't produce itself." However, the extent to which sanctions slowed Tehran's program is unclear. Donilon also cited "mistakes and difficulties in Iran" as obstacles to the program's progress. Former IAEA Deputy Director General Heinonen stated that "[w]e do not know" whether Iran's delays in deploying advanced centrifuges are attributable to "lack of raw materials or design problems," according to a 2012 press report. Furthermore, reports from the Office of the Director of National Intelligence covering 2009-2011 stated that "some obstacles slowed" the progress of Iran's nuclear program during those years, but the report did not name those obstacles. The extent to which alleged efforts by the United States and other governments, including Israel's, to sabotage Iran's centrifuge program have affected Tehran's nuclear program is unclear. The New York Times reported in 2009 that such efforts have included "undermin[ing] electrical systems, computer systems and other networks on which Iran relies," according to unnamed senior U.S. and foreign government officials. One effort involved foreign intelligence services sabotaging "individual power units that Iran bought in Turkey" for Tehran's centrifuge program. "A number of centrifuges blew up," according to the Times . Western governments have reportedly made other efforts to sabotage centrifuge components destined for Iran, according to some nongovernmental experts. Iranian officials have asserted that Western countries have tampered with components in transit to Iran's enrichment facilities, directly sabotaged those facilities, and conducted espionage in the country. In addition, New York Times reporter James Risen wrote in 2006 that, according to unnamed U.S. officials, the United States engaged in a covert operation to provide Iran with flawed blueprints for a device designed to trigger a nuclear explosion. The United States and Israel have also reportedly executed cyberattacks on Iran's nuclear facilities. Perhaps the best known of these used the Stuxnet computer worm, which was discovered in 2010 and probably developed by a government to attack Iran's enrichment facilities. Some governments have reportedly assassinated Iranians associated with Iran's nuclear program. The United States also may have obtained information from Iranian officials who defected as part of a CIA program to induce them to do so. Statements from the U.S. intelligence community indicate that Iran has the technical capability to produce nuclear weapons. For example, the 2007 National Intelligence Estimate (NIE) assessed that "Iran has the scientific, technical and industrial capacity eventually to produce nuclear weapons if it decides to do so." More recently, then-Director of National Intelligence Clapper stated during a February 2016 Senate Armed Services Committee hearing that Iran "does not face any insurmountable technical barriers to producing a nuclear weapon." Obtaining fissile material is widely regarded as the most difficult task in building nuclear weapons. As noted, Iran is enriching uranium, but whether and to what extent Tehran has taken the other steps necessary for producing a nuclear weapon is unclear. A 2008 report from former IAEA Director-General ElBaradei points out that the IAEA, with the exception of a document related to uranium metal, has "no information ... on the actual design or manufacture by Iran" of components, nuclear or otherwise, for nuclear weapons. However, according to IAEA Director-General Amano's November 2011 report, the IAEA has "credible" information that Iran has carried out activities "relevant to the development of a nuclear explosive device." These include acquisition of "nuclear weapons development information and documentation" and work to develop "an indigenous design of a nuclear weapon including the testing of components." Although some of these activities have civilian applications, "others are specific to nuclear weapons," the report notes. Most of the report provides additional details about Iranian activities applicable to nuclear weapons development that were described in previous IAEA reports, although it does contain some previously unreported material. The program's purpose was "to develop a nuclear warhead for the Shahab-3 missile," a senior Administration official stated during a November 8, 2011, briefing about Amano's November 2011 report. A 2012 Department of Defense report described Amano's report as containing "extensive evidence of past and possibly ongoing Iranian nuclear weapons-related research and development work." (See Appendix E for more details about the IAEA's information regarding suspected military aspects of Iran's nuclear program.) Amano's November 2011 report states that, according to information available to the IAEA, Iranian activities related to building a nuclear explosive device "took place under a structured programme" prior to the end of 2003. That program, however, "was stopped rather abruptly pursuant to a 'halt order' instruction issued in late 2003 by senior Iranian officials," the report says. The weapons-related activities were consolidated under the "AMAD Plan" and "appear to have been conducted during 2002 and 2003." Nevertheless, "[t]here are also indications that some activities relevant to the development of a nuclear explosive device continued after 2003, and that some may still be ongoing," according to the report. According to an August 2014 State Department announcement, Iran established the Organization of Defensive Innovation and Research (SPND), which "is primarily responsible for research in the field of nuclear weapons development," in 2011. The SPND "took over some of the activities related to Iran's undeclared nuclear program," the announcement said. According to a 2012 Israeli intelligence report, the SPND was established for the purposes of preserving the technological ability and the joint organizational framework of Iranian scientists in the area of R&D of nuclear weapons, and for the purposes of retaining the skills of the scientists. This is [to] allow renewal of the activity necessary to produce weapon immediately when the Iranian leadership decides to do so. This report also indicates that Iran had not restarted the nuclear weapons program. During an March 2019 press briefing, a senior U.S. official described the SPND as an organization, chunks of which seem to have been created precisely in order to employ people on dual-use things that could easily be repurposed into the very kind of work that was being done before on the weapons program and…in a sense, to keep their skills sharp and available to the Iranian clerical regime. Amano's December 2, 2015, report assesses that Iran conducted "a range of activities relevant to the development of a nuclear explosive device ... prior to the end of 2003 as a coordinated effort," adding that "some [nuclear weapons-related] activities took place after 2003," but "were not part of a coordinated effort." The report concludes that "these activities did not advance beyond feasibility and scientific studies, and the acquisition of certain relevant technical competencies and capabilities." The IAEA "has no credible indications of activities in Iran relevant to the development of a nuclear explosive device after 2009," the report explains. Iran presented a written assessment of Amano's report on January 7, 2016. The document apparently acknowledges Iranian "scientific studies of dual-use technologies" for "peaceful civilian or conventional military uses," but also reiterated previous Iranian claims that the country has done no work on nuclear weapons and that some of the evidence underlying the agency's concerns is inauthentic. A May 1, 2018, IAEA statement reiterated the December 2015 report's conclusions following Israeli Prime Minister Benjamin Netanyahu's disclosure of documents concerning Iran's past nuclear weapons program, though the agency did not comment on the documents specifically. Similarly, Nicole Shampaine, the Chargé d'Affaires at the U.S. Mission to International Organizations in Vienna UNVIE, stated on June 5, 2018, that the Israeli disclosure "further reaffirms" the IAEA's December 2015 conclusion that Iran had conducted such research in the past. U.S. Ambassador Jackie Wolcott discussed the Israeli-disclosed documents in a March 2019 statement: The troubling question remains of why Iran sought to preserve this information and expertise. Iran's retention of the archive not only underscores the key weakness of the temporary restrictions in the JCPOA, but strikes at the heart of longstanding concerns that Iran continues to keep its nuclear options open. As we move forward, Iran must end its longstanding efforts to deny and conceal the reality of past nuclear weapons work. Our interest in resolving these issues is not to score political points, but to address critical verification issues with direct relevance to how we move forward. The facts of Iran's past nuclear weapons activities continue to have bearing on current questions about the possibility of undeclared nuclear material and activities in Iran. These issues must be addressed in a clear and straightforward manner, without further delay. The United States supports the IAEA's "continued, careful assessment of the nuclear archive materials," Wolcott added. According to some nongovernmental organization reports, the IAEA has assessed that Iran "has sufficient information to be able to design and produce a workable implosion nuclear device based upon HEU as the fission fuel." However, these reports cite information from an internal 2009 IAEA document that ElBaradei has described as a rolling text complied by the Agency's Department of Safeguards that included all the various pieces of information that had come in from different intelligence organizations, most of which IAEA inspectors had been unable to verify or authenticate ... by definition, it was a series of best guesses. The IAEA Deputy Director General for Safeguards at the time had neither "assessed" nor "signed off on" the document, ElBaradei added. For its part, the U.S. government has assessed that Iran has not mastered "all the necessary technologies" for building a nuclear weapon, a senior Administration official stated in November 2011. During the same briefing, a senior Administration official explained that "the fact that some activities have apparently continued after the full-scale program was shut down in 2003 suggests that there's been some advancement" in Iran's ability to develop nuclear weapons, but "since it appears to be relatively uncoordinated and sporadic activity ... the advancement probably hasn't been that dramatic." Perhaps reinforcing this point, Director Clapper stated during the February 2012 Senate Armed Services Committee hearing that "there are certain things" that Iran has not yet done to develop a nuclear weapon, but he did not elaborate. Ambassador Stephen D. Mull, then-Coordinator for Implementation of the JCPOA, told a Washington audience on January 21, 2016, that "there was a portion of the Iranian Government working in a very organized, systematic way to develop the capability to build a nuclear weapon. We don't know to the extent to which that knowledge has been tested or even survived." Amano's November 2011 report states that, according to a member of a "clandestine nuclear supply network" run by former Pakistani official Abdul Qadeer Khan, Iran "had been provided with nuclear explosive design information." However, this information may not be sufficient to produce a nuclear weapon. Although Khan's network supplied Libya with "documents related to the design and fabrication of a nuclear explosive device," according to the IAEA, these documents lacked "important parts" for making a nuclear weapon, according to ElBaradei. In addition to the documents supplied to Tripoli, members of the Khan network had computer files containing "drawings for the components of two smaller, more advanced nuclear weapons." However, according to former IAEA Deputy Director-General Olli Heinonen, these "detailed designs" were not "complete sets" of weapons design information. Other members of the network could have possessed more complete nuclear weapons designs, he said. The JCPOA indefinitely prohibits specific activities "which could contribute to the design and development of a nuclear explosive device." Neither Iran's comprehensive safeguards agreement nor its additional protocol explicitly prohibit these activities. As noted, the U.S. government assesses that Tehran has not mastered all of the necessary technologies for building a nuclear weapon. In addition, for 15 years Iran is to refrain from "producing or acquiring plutonium or uranium metals or their alloys" and "conducting R&D on plutonium or uranium (or their alloys) metallurgy, or casting, forming, or machining plutonium or uranium metal." Producing uranium or plutonium metals is a key step in producing nuclear weapons. A senior intelligence official explained during a December 2007 press briefing that the "acquisition of fissile material ... remains the governing element in any timelines" regarding Iran's production of a "nuclear device." The 2007 NIE argued that "centrifuge enrichment is how Iran probably could first produce enough fissile material for a weapon" and added that "the earliest possible date Iran would be technically capable of producing enough HEU for a weapon is late 2009." However, it was "very unlikely" that Iran would attain such a capability by that date, the estimate says, adding that "Iran probably would be technically capable of producing enough HEU for a weapon sometime during the 2010-2015 time frame." But the State Department Bureau for Intelligence and Research, the estimate says, judged that Tehran "is unlikely to achieve this capability before 2013" and all intelligence agencies recognized "the possibility that this capability may not be attained until after 2015." The frequently-cited benchmark for determining the minimum sufficient amount of weapons-grade HEU for a nuclear weapon is 27.8 kilograms of uranium containing 90% uranium-235, but the amount assumed by U.S. government estimates is unclear. To produce its first nuclear weapon, Tehran would likely need to produce more uranium-235. According to a 2011 International Institute for Strategic Studies report, "the fabrication of an initial bomb would involve an amount of unavoidable wastage." Then-Deputy Assistant Secretary of Defense Colin Kahl explained during a November 15, 2011, hearing that "the time to actually complete a testable [Iranian nuclear] device could shrink over time." Then-Secretary of Defense Leon Panetta told 60 Minutes in 2012 that, if Iran were to decide to build a nuclear weapon, "it would probably take them about a year to be able to produce a bomb and then possibly another one to two years in order to put it on a deliverable vehicle of some sort in order to deliver that weapon." Although, as noted, the United States estimated that Iran's Fordow enrichment facility "would be capable of producing approximately one weapon's worth" of HEU per year, whether and how that assessment factored into the U.S. timelines for Iranian nuclear weapons development is unclear. Then-Under Secretary of State for Political Affairs Wendy Sherman explained during an October 3, 2013, Senate Foreign Relations Committee hearing that Iran would need as much as one year to produce a nuclear weapon if the government made the decision to do so. At the time, Tehran would have needed two to three months to produce enough weapons-grade HEU for a nuclear weapon. Iran's December 28, 2015, JCPOA-mandated shipment of LEU to Russia lengthened this time to one year, according to February 9, 2016, congressional testimony from then-Director of National Intelligence Clapper. Current Director of National Intelligence Daniel Coats reiterated this assessment in several congressional hearings. A senior U.S. official followed suit in a March 2019 press briefing. The U.S. estimates described above apparently assume that Iran would use its declared nuclear facilities to produce fissile material for a weapon. However, the 2007 NIE states that Iran "probably would use covert facilities—rather than its declared nuclear sites—for the production of highly enriched uranium for a weapon." Similarly, a CIA report covering 2004 concluded that "inspections and safeguards will most likely prevent Tehran from using facilities declared to the IAEA directly for its weapons program as long as Iran remains a party to the NPT." Director Clapper echoed this assessment in a March 2015 interview. Iran would probably prefer to avoid using its safeguarded facilities, partly because the IAEA would likely detect an Iranian attempt to use them for producing weapons-grade HEU. According to former Deputy Assistant Secretary Kahl, Tehran "is unlikely to dash for a bomb in the near future because IAEA inspectors would probably detect Iranian efforts to divert low-enriched uranium and enrich it to weapons-grade level at declared facilities." Similarly, then-Deputy Assistant Secretary of Defense for Media Operations John Kirby told reporters on December 21, 2011, that were Iran to begin producing a nuclear weapon, IAEA inspectors would likely give sufficient warning for the United States to take action. Former IAEA Deputy Director-General Heinonen observed in 2010 that Iran would probably be caught if it attempted to divert more than "small quantities" of nuclear material from its safeguarded nuclear facilities. It would be extremely difficult to reconfigure the cascades in the Natanz facility without detection and, in any case, IAEA inspectors measure the isotopic content of enriched uranium and would thereby detect Iranian production of weapons-grade HEU. More recently, Clapper testified that the JCPOA has also enhanced the transparency of Iran's nuclear activities ... [a]s a result, the international community is well postured to quickly detect changes to Iran's declared nuclear facilities designed to shorten the time Iran would need to produce fissile material. Although Iran could eject IAEA inspectors and/or withdraw from the NPT, such a move would be "an incredibly provocative action and very risky for Iran to undertake," then-Department of State Special Advisor Einhorn argued in 2011, adding that Iran was unlikely to take such a risk because its operating first-generation centrifuges are inefficient. It is worth noting that such an action would be virtually unprecedented. A senior intelligence official explained in December 2007 that Iran could use knowledge gained from its Natanz facilities at covert enrichment facilities. According to the NIE, a "growing amount of intelligence indicates Iran was engaged in covert uranium conversion and uranium enrichment activity," but Tehran probably stopped those efforts in 2003. U.S. officials have argued that Iran currently does not appear to have any nuclear facilities unknown to the United States. Then- CIA Director John Brennan stated during a March 2015 interview that the United States has "a good understanding of what the Iranian nuclear program entails." During a July 31 , 2015, press briefing about possible Iranian undeclared nuclear facilities, U.S. Secretary of Energy Ernest Moniz stated that "we feel pretty confident that we know their current configuration." U.S. officials have express ed confidence in the ability of U.S. intelligence to detect Iranian covert nuclear facilities . In addition to the possible nuclear weapons-related activities discussed above, Iran has continued to develop ballistic missiles, which could potentially be used to deliver nuclear weapons. It is worth noting, however, that then-Director of National Intelligence Dennis Blair indicated during a 2009 Senate Armed Services Committee hearing that Iran's missile developments do not necessarily indicate that the government is also pursuing nuclear weapons, explaining that "I don't think those missile developments ... prejudice the nuclear weapons decision one way or another. I believe those are separate decisions." Iran is developing missiles and space launch vehicles "for multiple purposes," he added. Similarly, in a June 2015 statement to Parliament, British Foreign and Commonwealth Office official Tobias Ellwood stated that "we are not aware of any current links between Iran's ballistic missile programme and nuclear programme." In any case, Tehran's nuclear program raised concerns for various other reasons. First, Iran was secretive about the program. For example, Tehran hindered the IAEA investigation by failing to disclose numerous nuclear activities, destroying evidence, and making false statements to the agency. Moreover, although Iran's cooperation with the agency improved, the IAEA still repeatedly criticized Tehran for failing to cooperate fully with the agency's investigation of certain issues concerning Iran's nuclear program. Second, many observers have questioned Iran's need for nuclear power, given the country's extensive oil and gas reserves. The fact that Tehran resumed its nuclear program during its 1980-1988 war with Iraq has also cast doubt on the energy rationale. Furthermore, many countries with nuclear power reactors purchase nuclear fuel from foreign suppliers—indeed, Russia has provided fuel for the Bushehr reactor—a fact that calls into question Iran's need for an indigenous enrichment capability. Moreover, Iranian officials acknowledge that Iran lacks sufficient uranium deposits for its planned nuclear power program. Some government officials have expressed skepticism regarding Iran's stated rationale for its Arak reactor. Tehran says that the reactor is necessary to produce medical isotopes and to replace the Tehran Research Reactor (TRR). However, the TRR is capable of producing such isotopes and has unused capacity. Furthermore, as noted, Iran expressed the desire to obtain more fuel for the TRR. In addition, nonproliferation experts have argued that a new heavy-water reactor would be unnecessary for producing such isotopes. As noted, Iran has rendered the Arak reactor's original core inoperable pursuant to the JCPOA, which also commits Tehran to redesign and rebuild the reactor based on a design agreed to by the P5+1. Iran has maintained that its nuclear program has always been exclusively for peaceful purposes. As noted, the Iranian government says that it plans to expand its reliance on nuclear power in order to generate electricity. Indeed, some experts have documented Tehran's projected difficulty in exporting oil and natural gas without additional foreign investment in its energy infrastructure. Iran has argued that its covert nuclear procurement efforts were necessary to counter Western efforts to deny it nuclear technology—a claim that appears to be supported by a 1997 CIA report. Tehran argues that it cannot depend on foreign suppliers for such fuel because such suppliers have been unreliable in the past. At least one expert has described Iran's inability to obtain nuclear fuel from an international enrichment consortium called Eurodif. During the 1970s, Iran had reached an agreement with Eurodif that entitled Iran to enriched uranium from the consortium in exchange for a loan. Former AEOI President Aghazadeh also argued that although Iran does not need to produce fuel for the Bushehr reactor, the government needed to complete the Natanz facility to provide fuel for the planned Darkhovin reactor. Other factors also suggest that Iran may not have had an active nuclear weapons program after 2003. First, as noted, the IAEA has resolved the outstanding issues described in the August 2007 Iran-IAEA work plan, and the agency has not discovered significant undeclared Iranian nuclear activities for a number of years. Second, Tehran, beginning in 2003, has been willing to disclose previously undeclared nuclear activities to the IAEA. Third, Iran made important changes to the administration of its nuclear program in the second half of 2003—changes that produced greater openness with the IAEA and may have indicated a decision to stop a nuclear weapons program. Fourth, as noted above, Iranian officials have stated numerous times that Tehran is not seeking nuclear weapons, partly for religious reasons—indeed, Khamene'i has issued a fatwa declaring that "the production, stockpiling, and use of nuclear weapons are forbidden under Islam," according to Iranian officials. A change in this stance could damage Iranian religious leaders' credibility. In 2013, an Iranian Foreign Ministry spokesperson described the fatwa as the "operational instruction" for Iran's government. A senior Iranian official stated in February 2019 that "according to the fatwa (religious verdict) of Ayatollah Khamenei, which is based on the hadith of the Prophet, Iran has no intention to make an atomic bomb." Mark Fitzpatrick of the International Institute for Strategic Studies has argued that "given the pervasive religiosity of the regime, it is unlikely that Iran's supreme leader would be secretly endorsing military activity in explicit contradiction of his own religious edict." Fifth, Iranian officials argued that nuclear weapons would not improve the country's security, arguing that Iran would not be able to compete with the nuclear arsenals of larger countries, such as the United States. Moreover, the Iranian government has asserted that "Iran today is the strongest country in its immediate neighborhood. It does not need nuclear weapons to protect its regional interests." The U.S.-led spring 2003 invasion of Iraq, which overthrew Iraqi leader Saddam Hussein and thereby eliminated a key rival of Iran, may also have induced Tehran to decide that it did not need nuclear weapons. The government has also argued that a nuclear weapons program "would be prohibitively expensive, draining the limited economic resources of the country." In any case, since Iran has implemented its JCPOA commitments, which, as noted, include significant limits on Iran's nuclear program and transparency requirements with respect to that program, U.S. officials have argued that the Iranian nuclear program poses a less severe proliferation threat. For example, then-Secretary of Defense Ashton Carter testified in March 2016 that the agreement "places significant limitations on Iran that will effectively cut off its pathways to the fissile material for a nuclear bomb." Since at least 2007, the U.S. intelligence community has issued unclassified assessments that Iran has not decided whether to develop nuclear weapons. According to the 2007 NIE, "Iranian military entities were working under government direction to develop nuclear weapons" until fall 2003, after which Iran halted its nuclear weapons program "primarily in response to international pressure." The NIE defines "nuclear weapons program" as "Iran's nuclear weapon design and weaponization work and covert uranium conversion-related and uranium enrichment-related work." The NIE adds that the intelligence community also assessed "with moderate-to-high confidence that Tehran at a minimum is keeping open the option to develop nuclear weapons." The NIE also states that, because of "intelligence gaps," the Department of Energy and the National Intelligence Council assessed "with only moderate confidence that the halt to those activities represents a halt to Iran's entire nuclear weapons program." The NIE added that "[s]ince fall 2003, Iran has been conducting research and development projects with commercial and conventional military applications—some of which would also be of limited use for nuclear weapons." The NIE also states that "Tehran's decision to halt its nuclear weapons program suggests it is less determined to develop nuclear weapons than we have been judging since 2005." The change in assessments, a senior intelligence official said in December 2007, was the result of "new information which caused us to challenge our assessments in their own right, and illuminated previous information for us to be able to see it perhaps differently than we saw before, or to make sense of other data points that didn't seem to self-connect previously." According to press accounts, this information included various written and oral communications among Iranian officials indicating that the program had been halted. As noted, the United States may also have obtained information from Iranian officials who defected as part of a CIA program to induce them to do so, as well as from penetration of Iran's computer networks. In addition, the NIE incorporated open-source information, such as photographs of the Natanz facility that became available after members of the press toured the facility. According to the 2007 NIE, the intelligence community assessed "with moderate-to-high confidence that Iran [did] not have a nuclear weapon." The community assessed "with low confidence that Iran probably [had] imported at least some weapons-usable fissile material," but still judged "with moderate-to-high confidence" that Tehran still lacked sufficient fissile material for a nuclear weapon. On several occasions, the U.S. intelligence community has reaffirmed the 2007 NIE's assessment that Iran halted its nuclear weapons program but is keeping its options open. The late-September 2009 revelation of the Fordow facility increased suspicions that Iran may have restarted its nuclear weapons program. As noted, some U.S. officials indicated that the facility was likely intended for a nuclear weapons program. Nevertheless, Administration talking points made public on September 25, 2009, stated that the intelligence community still assessed that "Iran halted its nuclear weapons program in 2003." More recently, then-Director of National Intelligence Clapper testified in February 2016 that [w]e continue to assess that Iran's overarching strategic goals of enhancing its security, prestige, and regional influence have led it to pursue capabilities to meet its nuclear energy and technology goals and give it the ability to build missile-deliverable nuclear weapons, if it chooses to do so. Its pursuit of these goals will dictate its level of adherence to the JCPOA over time. We do not know whether Iran will eventually decide to build nuclear weapons." Director of National Intelligence Coats reiterated the last sentence in May 2017 testimony. He testified in January 2019 that the U.S. intelligence community "continue[s] to assess that Iran is not currently undertaking the key nuclear weapons-development activities we judge necessary to produce a nuclear device." Additional recent statements from U.S. officials indicate that Iran has not resumed its nuclear weapons program. Any decision to produce nuclear weapons "will be made by the Supreme Leader," Clapper stated in April 2013. The November 2011 report from IAEA Director-General Amano appears to support the U.S. assessment. As noted, the report states that Iranian activities related to building a nuclear explosive device "took place under a structured programme," but senior Iranian officials ordered a halt to the program in late 2003. Echoing the judgment of the 2007 NIE, Amano's report mentions "indications that some activities relevant to the development of a nuclear explosive device continued after 2003," adding that some such activities "may still be ongoing." Most of the activities listed in the report occurred before the end of 2003. During a briefing about Amano's report, a senior Administration official described Iran's post-2003 weapons-related work as "a much less coordinated ... more sporadic set of research activities," some of which "are sort of related to nuclear weapons development." As noted, an April 2012 Department of Defense report described Amano's report as containing "extensive evidence of past and possibly ongoing Iranian nuclear weapons-related research and development work." Amano's December 2, 2015, report assesses that "before the end of 2003, an organizational structure was in place in Iran suitable for the coordination of a range of activities relevant to the development of a nuclear explosive device." S ome Iranian nuclear weapons-related activities " took place after 2003," the report adds, noting that these activities "were n ot part of a coordinated effort. " The IAEA "has no credible indications of activities in Iran relevant to the development of a nuclear explosive device after 2009," the report explains. (See also " Nuclear Weapon Development Capabilities .") Some foreign intelligence agencies have apparently concurred with the U.S. assessment that Iran has not yet decided to build nuclear weapons. Director of the French General Directorate of External Security Erard Corbin de Mangoux stated in an interview published in 2010 that "[w]e do not yet know whether Tehran's objective is to enable itself to acquire such a capability (so-called 'threshold status') or actually to possess it." In 2012, Israeli Foreign Minister Avigdor Lieberman appeared to confirm reports that Israeli intelligence shares this U.S. assessment. Moreover, according to a 2012 Israeli intelligence report, "until 2003," Iran had a "set nuclear program ... for R&D of nuclear weapons." However, the report indicates that Iran had not restarted the nuclear weapons program. German intelligence assessments have also reportedly concurred with this assessment. It is worth noting that the February 2018 Nuclear Posture Review asserts that "Iran's development of increasingly long-range ballistic missile capabilities, and its aggressive strategy and activities to destabilize neighboring governments, raises questions about its long-term commitment to foregoing nuclear weapons capability." National Security Adviser John Bolton stated during a January 6, 2019, press conference that "we have little doubt that Iran's leadership is still strategically committed to achieving deliverable nuclear weapons." Other findings of the NIE indicate that the international community may, for the foreseeable future, have to accept some risk that Iran will develop nuclear weapons. According to the 2007 NIE, "only an Iranian political decision to abandon a nuclear weapons objective would plausibly keep Iran from eventually producing nuclear weapons—and such a decision is inherently reversible." As noted, the U.S. intelligence community assesses that Iran has the capacity to produce nuclear weapons at some point. This is not to say that an Iranian nuclear weapons capability is inevitable. As noted above, Iran does not yet have such a capability. But Tehran adherence to the JCPOA is probably necessary to provide the international community with confidence that it is not pursuing a nuclear weapon. The production of fissile material is widely considered the most difficult step in nuclear weapons development. However, even if it had the ability to produce weapons-grade HEU, Iran would still face challenges in producing nuclear weapons, such as developing a workable physics package and effective delivery vehicles. A 1978 CIA report points out that there is a great difference between the development and testing of a simple nuclear device and the development of a nuclear weapons system, which would include both relatively sophisticated nuclear designs and an appropriate delivery system. Moreover, Iran would face significant challenges if it were to attempt to develop and produce HEU-based nuclear weapons covertly; although, as noted, covert production would probably be Tehran's preferred option. Covert centrifuge facilities are notoriously difficult for intelligence agencies to detect, but Iran may not be able to complete a covert centrifuge facility without detection. A 2005 International Institute for Strategic Studies report concluded that "an Iranian planner would have little basis for confidence that significant nuclear facilities could be kept hidden." Tehran would need to hide a number of activities, including uranium conversion, the movement of uranium from mines, and the movement of centrifuge feedstock. Alternatively, Iran could import uranium ore or centrifuge feedstock, but the government would also need to do so covertly. Tehran's implementation of the JCOA has further decreased the probability that the government could successfully conceal a nuclear weapons program. The difficulty of the above task becomes clearer when one considers that foreign intelligence agencies apparently possess a significant amount of information about the Iran's enrichment program. First, both the Natanz and Fordow facilities were discovered by foreign governments before they became operational. Second, the development of the Stuxnet computer worm, discussed above, indicates that at least one foreign government possesses a large amount of information about Iran's centrifuge program, which could not have been obtained via IAEA reporting, according to some experts. As noted, U.S. officials have express ed confidence in the ability of U.S. intelligence to detect Iranian covert nuclear facilities . It is worth noting that, without conducting explosive nuclear tests, Iran could produce only fairly simple nuclear weapons, which are not deliverable by longer-range missiles. Such tests, many analysts argue, would likely be detected. Francois Geleznikoff, director of military applications at Le Commissariat à L'Energie Atomique et aux Énergies Alternative in France, described during a 2018 National Assembly hearing his directorate's monitoring of Iran's and North Korea's nuclear programs: This monitoring depends primarily on the detection of any nuclear tests that they may carry out. Thanks to the international detection system established by the Comprehensive Nuclear Test Ban Treaty, in which France participates actively, and thanks to our own analysis, we are able to alert the French authorities within 30 minutes of a North Korean test, and the same would apply in the event of an Iranian test, for instance. Moreover, moving from the production of a simple nuclear weapon to more sophisticated nuclear weapons could take several additional years. Appendix A. Iranian Statements on Nuclear Weapons Iranian officials have repeatedly asserted that the country's nuclear program is exclusively for peaceful purposes. For example, Supreme Leader Ayatollah Ali Khamene'i declared during a June 3, 2008, speech that Iran is opposed to nuclear weapons "based on religious and Islamic beliefs as well as based on logic and wisdom." He added, "Nuclear weapons have no benefit but high costs to manufacture and keep them. Nuclear weapons do not bring power to a nation because they are not applicable. Nuclear weapons cannot be used." Similarly, then-Iranian Foreign Ministry spokesperson Hassan Qashqai stated on November 10, 2008, that "pursuance of nuclear weapons has no place in the country's defense doctrine." Khamene'i stated in 2012 that Ideologically and religiously speaking, we believe that it is not right [to have nuclear weapons]. We believe that this move [making nuclear weapons] and the use of such weapons are a great sin. We also believe that stockpiling such weapons is futile, expensive and harmful; and we would never seek this. Asked in 2012 if Iran is trying to develop the capability to produce a nuclear weapon, Ambassador Mohammad Chasee, Iran's Permanent Representative to the United Nations, stated that "[w]e are not going to develop the capacity to be able to make any weapon of mass destruction." Iranian Foreign Minister Javad Zarif argued in 2014 that Khamene'i "has explicitly declared his opposition with regard to the manufacture, stockpile and use of nuclear weapons," and observed that "nuclear weapons have no place in Iran's defense doctrine." More recently, President Hassan Rouhani stated in 2018 that "we are not thinking about developing nuclear weapons, nor will we think about it. The Supreme Leader [Ali Khamenei] has banned it and said that it is not appropriate." Appendix B. Organization of Iran's Nuclear Program The Atomic Energy Organization of Iran (AEOI), which the government established in 1974, operates Iran's declared nuclear program and has a variety of peaceful programs in areas such as agriculture, medicine, and basic nuclear research and development. According to the U.S. Department of the Treasury, the AEOI "has operational and regulatory control over Iran's nuclear program," "reports directly to the Iranian President," and is the "main Iranian organization responsible for research and development activities in the field of nuclear technology." Iran's Minister of Science, Research and Technology stated in January 2019 that "the AEOI acts upon decisions made by the country's Supreme National Security Council." The AEOI has been Tehran's main interlocutor with the IAEA. According to an August 2008 Institute for Science and International Security (ISIS) report, the AEOI controls the country's centrifuge program, but that program is operated by an AEOI entity called the Kalaye Electric Company. AEOI officials have told the IAEA that Iran decided to begin its centrifuge enrichment program in 1985. The program consisted of three phases: activities during the first phase, from 1985 until 1997, had been located mainly at the AEOI premises in Tehran; during the second phase, between 1997 and 2002, the activities had been concentrated at the Kalaye Electric Company in Tehran; during the third phase, 2002 to the present, the R&D and assembly activities were moved to Natanz. Gholamreza Aghazadeh's term as AEOI president, which began in 1997, marked an acceleration of Iran's enrichment program. According to President Hassan Rouhani, who headed the 2003-2005 negotiations concerning the nuclear program, the government in 1998 formed the Supreme Council for New Technologies, chaired by then-President Mohammad Khatami, which focused on the nuclear program. Beginning around 1999, Iran's central government gave the AEOI "authorities that it did not have before," Rouhani stated in a 2004 speech, explaining that we gave the agency a freer hand with new credits and a more liberal spending procedure, new facilities, and special regulations. This allowed them to become more active, without being forced to go through bureaucratic and regulatory labyrinths. Nuclear Weapons Program Beginning in the late 1980s, Iran's nuclear weapons program was coordinated by entities connected with Iran's Ministry of Defense Armed Forces Logistics (MODAFL). The AMAD Plan took over these activities several years later; the projects were "allegedly managed through the 'Orchid Office.'" After Iran ended the nuclear weapons program in 2003, "staff remained in place to record and document the achievements of their respective projects," according to information provided to the IAEA by unnamed governments. Later, "equipment and work places were either cleaned or disposed of so that there would be little to identify the sensitive nature of the work which had been undertaken." Tehran established an organization called the Organization of Defensive Innovation and Research (SPND) in 2011 by an individual who had "managed activities useful in the development of a nuclear explosive device" as part of the Amad Plan and associated entities. The SPND "is completely separate from Iran's civil nuclear program," a senior U.S. official explained during a March 2019 press briefing. According to a 2012 Israeli intelligence document, Iran established the SPND "for the purposes of preserving the technological ability and the joint organizational framework of Iranian scientists in the area of R&D in nuclear weapons, and for the purposes of retaining the skills of the scientists." These activities were to "allow renewal of the activity necessary to produce weapons immediately when the Iranian leadership decides to do so." During an March 2019 press briefing, a senior U.S. official described the SPND as an organization, chunks of which seem to have been created precisely in order to employ people on dual-use things that could easily be repurposed into the very kind of work that was being done before on the weapons program and … in a sense, to keep their skills sharp and available to the Iranian clerical regime. Nevertheless, the IAEA reported in December 2015 that, despite the SPND's establishment in 2011, the post-2003 activities "were not part of a coordinated effort" and the agency "has no credible indications of activities in Iran relevant to the development of a nuclear explosive device after 2009." (For more details, see Appendix E .) The AEOI had links with some entities that were apparently connected to the Amad Plan. For example, a company called Kimia Maadan "was a cover company for chemical engineering operations under the AMAD Plan while also being used to help with procurement for the [AEOI]." The organization contracted with the same company to design and build the Gchine mill. Furthermore, Tehran's AEOI-run centrifuge program had connections to entities controlled by Iran's MODAFL, which controlled the Amad Plan. For example, Iran fabricated some components for its second-generation centrifuge in a workshop located on a site belonging to Iran's Defence Industries Organization, which was part of MODAFL. Nevertheless, several factors indicate that the AEOI's illicit nuclear activities were not necessarily part of the nuclear weapons program. First, the NIE appeared to exclude the AEOI-run enrichment program. Explaining that the U.S. intelligence community defined the weapons activities as "nuclear weapon design and weaponization work and covert uranium conversion-related and uranium enrichment-related work," the estimate added that "Iran's declared civil work related to uranium conversion and enrichment" was not part of the weapons program. Moreover, a November 2011 IAEA description of the suspected past nuclear weapons program's management structure omits the AEOI. Lastly, September 2009 U.S. intelligence community talking points regarding the September 2009 joint British, French, and U.S. revelation of Iran's Fordow centrifuge facility state that the plant's existence did "not contradict" the 2007 NIE's conclusions regarding Iran's nuclear weapons program. One reason for this assessment, the talking points suggest, was that the Fordow facility was developed by the AEOI. U.S. and British officials have stated that Iranian missile development is not currently linked to the nuclear program. Iran's MODAFL oversees Iran's ballistic missile program. The Aerospace Industries Organization, a MODAFL subsidiary, oversees the country's missile production. Although some Islamic Revolutionary Guard Corps (IRGC) entities are associated with MODAFL and the IRGC Air Force operates Iran's ballistic missiles, these entities do not appear to be associated with the AEOI. A State Department official explained in October 2016 that the IRGC "was not responsible for" activities related to the possible military dimensions of Iran's nuclear program. Appendix C. Multilateral Diplomacy Concerning Iran's Nuclear Program In fall 2002, the IAEA began to investigate Iran's nuclear activities at Natanz and Arak. Inspectors visited the sites the following February. The IAEA board adopted its first resolution, which called on Tehran to increase its cooperation with the agency's investigation and to suspend its uranium enrichment activities, in September 2003. The next month, Iran concluded an agreement with France, Germany, and the United Kingdom, collectively known as the "E3," to suspend its enrichment activities, sign and implement an Additional Protocol to its IAEA safeguards agreement, and comply fully with the IAEA's investigation. As a result, the IAEA board decided to refrain from referring the matter to the U.N. Security Council, despite U.S. advocacy for such a referral. Statements from current and former Iranian officials indicate that during fall 2003, Tehran feared that the United States might use Security Council referral as a means to undertake military action or other coercive measures against Iran. The IAEA's investigation, as well as information Tehran provided after the October 2003 agreement, ultimately revealed that Iran had engaged in a variety of clandestine nuclear-related activities, some of which violated Iran's safeguards agreement. These included plutonium separation experiments, uranium enrichment and conversion experiments, and importing various uranium compounds. After October 2003, Iran continued some of its enrichment-related activities, but Tehran and the E3 agreed in November 2004 to a more detailed suspension agreement. During negotiations between fall 2003 and summer 2005, both Iran and the E3 offered a number of proposals, although the two sides never reached agreement. According to one former British official involved in the negotiations, a chief obstacle was E3 opposition to a 2005 Iranian proposal that would have included a limited Iranian enrichment program. A former Iranian official argued that the perceived lack of success of Iranian officials who had participated in negotiations with the E3 discredited those officials in the eyes of other Iranian officials. The United States influenced several aspects of the E3 negotiations during this time. For example, the George W. Bush Administration opposed an E3 request to ease sanctions on certain U.S. goods. The United States also persuaded the E3 to refrain from agreeing to any arrangement with Iran that included even a limited Iranian enrichment program, according to accounts from E3 officials directly involved in the diplomacy. Former President George W. Bush has written that the United States' "ultimate goal" was "stopping Iranian enrichment." Iran resumed uranium conversion in August 2005 under the leadership of President Mahmoud Ahmadinejad, who had been elected two months earlier. On September 24, 2005, the IAEA Board of Governors adopted a resolution that, for the first time, found Iran to be in noncompliance with its IAEA safeguards agreement. The board, however, did not refer Iran to the Security Council, choosing instead to give Tehran additional time to comply with the board's demands. Iran announced in January 2006 that it would resume research and development on its centrifuges at Natanz. In response, the IAEA board adopted a resolution on February 4, 2006, that referred the matter to the Security Council. Two days later, Tehran announced that it would stop implementing its Additional Protocol. In June 2006, China, France, Germany, Russia, the United Kingdom, and the United States, collectively known as the "P5+1," presented a proposal to Iran that offered a variety of incentives in return for Tehran taking several steps to assuage international concerns about its enrichment and heavy-water programs. The proposal called on the government to address the IAEA's "outstanding concerns ... through full cooperation" with the agency's ongoing investigation of Tehran's nuclear programs, to "suspend all enrichment-related and reprocessing activities," and to resume implementing its Additional Protocol. Then-European Union High Representative for Common Foreign and Security Policy Javier Solana presented a revised version of the 2006 offer to Iran in June 2008. P5+1 representatives discussed the new proposal with Iranian officials the next month. Iran provided a follow-up response in August 2008, but the six countries deemed it unsatisfactory. Tehran told the IAEA that it would implement its Additional Protocol "if the nuclear file" were "returned from the Security Council" to the agency. It is not clear that the council could have met this condition. The 2006 offer's requirements were also included in several U.N. Security Council resolutions, including Resolution 1929, which was adopted on June 9, 2010. Iran issued another proposal in early September 2009, which described a number of economic and security issues as potential topics for discussion but only obliquely mentioned nuclear issues and did not explicitly mention Iran's nuclear program. Tehran Research Reactor Discussions After an October 1, 2009, meeting in Geneva with the P5+1 and High Representative Solana, Iranian officials repeatedly stated that Tehran wanted future discussions about its September 2009 proposal. Nevertheless, during that meeting, Iranian officials agreed in principle to a proposal that would provide LEU fuel containing about 20% uranium-235 for Iran's U.S.-supplied Tehran Research Reactor (TRR), which produces medical isotopes and operates under IAEA safeguards. Iran asked the IAEA in a June 2, 2009, letter to provide fresh fuel for its U.S-supplied TRR. Initially fueled by U.S.-supplied HEU, the reactor was converted to use LEU fuel in 1994 after Argentina in 1987 agreed to supply the reactor with such fuel, which contained about 20% uranium-235. Subsequent to Iran's June 2009 request, the United States and Russia presented a proposal to the IAEA (which the agency conveyed to Iran) for providing fuel for the reactor. According to the proposal, Iran would have transferred approximately 1,200 kilograms of its low-enriched uranium hexafluoride to Russia, which would have either enriched the uranium to about 20% uranium-235 or produced such LEU from Russian-origin uranium. Moscow would then have transferred the low-enriched uranium hexafluoride to France for fabrication into fuel assemblies. Finally, Paris would have transferred the assemblies to Russia for shipment to Iran. France would have delivered the fuel within about one year. As of October 30, 2009, Iran had produced 1,763 kilograms of low-enriched uranium hexafluoride containing less than 5% uranium-235. Beginning on October 19, 2009, Iranian officials met with officials from the IAEA, France, Russia, and the United States to discuss details of implementing the proposal, such as the fuel price, contract elements, and a timetable for shipping the fuel. Two days later, then-IAEA Director-General Mohamed ElBaradei announced the conclusion of a "draft agreement," which was drafted by the IAEA. Iran, France, Russia, and the United States held further discussions regarding the proposal's implementation, but they did not reach agreement with Tehran. Iran resisted transferring all 1,200 kilograms of low-enriched uranium hexafluoride out of the country before receiving the reactor fuel, arguing that the proposal needed more credible assurances that the fuel would actually be delivered. During the last few months of 2009, Iranian officials suggested different compromises, such as shipping its low-enriched uranium hexafluoride out of the country in phases or simultaneously exchanging that material for the TRR fuel on an Iranian island or in a third country, but these proposals were not accepted by the United States, France, and Russia. Further details about the French, Russian, and U.S. proposals later became public. For example, the IAEA had agreed to take formal custody of any Iranian low-enriched uranium hexafluoride transferred pursuant to a TRR agreement. In addition, France, Russia, and the United States had agreed to a "legally binding Project and Supply Agreement"; agreed to "support technical assistance through the IAEA to ensure" that the TRR would operate safely; and expressed support for allowing Iran to transfer its low-enriched uranium hexafluoride to a third country, which would hold that material in escrow until the TRR fuel was fabricated. The United States also offered "substantial political assurances that the agreement would be fulfilled." An April 20, 2010, letter from then-President Obama to then-President Brazilian President Luis Inácio Lula da Silva stated that the United States had expressed its willingness to "potentially even play a more direct role in the fuel production process," but did not elaborate. The October 2009 IAEA draft did not include an explicit prohibition on Iranian production of uranium enriched to about 20% uranium-235. Instead, the agreement's proponents argued that the supply of fuel for the TRR would obviate the need for Tehran to produce the fuel on its own. The escrow proposal described in the previous paragraph was not contained in the October 2009 IAEA draft. Whether the other provisions described above were explicitly contained in that draft is unclear because no public official copy of it exists. Following a November 20, 2009, meeting, the P5+1 issued a joint statement expressing disappointment with Tehran's failure to respond positively to the TRR proposal. "We have agreed to remain in contact and expect a further meeting soon to complete our assessment of the situation and to decide on our next steps," the statement said. Although some subsequent Iranian statements suggested that Iran was still open to some version of the IAEA proposal, Tehran never officially accepted it. Following a May 17, 2010, meeting of Iranian President Ahmadinejad, Turkish Prime Minister Recep Tayyip Erdogan, and Brazilian President Lula, Iran accepted a proposal, known as the Tehran Declaration, for supplying the TRR with fuel. Iran conveyed its acceptance of the declaration in a May 24, 2010, letter to the IAEA. The Tehran Declaration contained some of the same elements as the October 2009 IAEA draft proposal and other elements described in a February 12, 2010, letter to the IAEA. For example, the declaration stated that Iran would be willing to "deposit" 1,200 kilograms of LEU in Turkey. Iran would deposit the fuel, which would be subject to IAEA monitoring in Turkey, "not later than one month" after reaching an agreement regarding the details of the exchange with France, Russia, the United States, and the IAEA. However, unlike the IAEA draft proposal, the declaration did not mention an ultimate destination for the LEU to be deposited in Turkey. As noted, Tehran had resisted transferring all 1,200 kilograms of LEU out of the country before receiving fuel for the TRR. IAEA Director-General Amano told the agency's Board of Governors on June 7, 2010, that he had "immediately conveyed Iran's letter" to France, Russia, and the United States "and asked for their views." Those three governments responded to the IAEA two days later with letters and a joint paper titled "Concerns about the Joint Declaration Conveyed by Iran to the IAEA." The paper conveyed several reservations about the Tehran Declaration, but did not reject it outright. One reason for the U.S. refusal to accept the proposal was fear that the proposal would disrupt efforts to persuade the Security Council to adopt a resolution imposing additional sanctions on Iran (the council adopted Resolution 1929 in June 2010). Further Talks Iran and the P5+1 met in December 2010 and January 2011, but the two meetings, held in Geneva and Istanbul, respectively, produced no results. In April 2012, the two sides resumed talks in Istanbul. Iran and the P5+1 subsequently held two rounds of talks—a May meeting in Baghdad and a June meeting in Moscow. In addition, the two sides held expert-level discussions in Istanbul in July 2012. Former U.S. officials involved in the JCPOA negotiations have stated that the U.S. decision, articulated to Iran during 2013, to drop its previous insistence that Iran end its enrichment program was decisive for reaching a final agreement. Iranian and Russian officials have made similar claims. Following the April 2012 talks, the P5+1 stated that the process of inducing Iranian compliance with "all its international obligations" would be "guided by the principle of the step-by-step approach and reciprocity." The P5+1 presented their proposal the next month during the Baghdad meeting. The six governments demanded that Tehran end its production of enriched uranium containing approximately 20% uranium-235; ship to a third country Iran's stockpile of uranium enriched to this level (this uranium would be under IAEA monitoring); halt enriching uranium, as well as installing centrifuges and centrifuge components, at the Fordow facility; and cooperate fully with the IAEA's investigation. Then-European Union High Representative Catherine Ashton for Common Foreign and Security Policy stated on May 24, 2012, that the P5+1 "put ideas on the table on reciprocal steps we would be prepared to take." These included refraining from imposing new sanctions on Iran; facilitating Iranian access to spare aircraft parts, as well as safety and repair inspections; providing fuel for the TRR; supporting IAEA technical cooperation regarding the TRR's safety; providing medical isotopes to Tehran; potentially reviewing suspended IAEA technical cooperation projects with Iran; and cooperating on Tehran's acquisition of a light-water reactor for producing radioisotopes. The two sides again held talks in February 2013. Technical experts from the P5+1 and Iran met the next month, and another round of talks at the political director level took place in April 2013. Following the June 2013 election of Iranian President Hassan Rouhani, many observers expressed optimism that these negotiations would produce an agreement. After Rouhani took office in August 2013, Iran and the P5+1 met twice later that year (once in October and once in November). The two sides met again on November 20, 2013, and agreed to an accord called the Joint Plan of Action (JPA) on November 24. This agreement set out an approach toward reaching a long-term comprehensive solution to international concerns regarding Iran's nuclear program. The two sides began implementing the JPA on January 20, 2014. The P5+1 and Iran agreed on a framework for a Joint Comprehensive Plan of Action (JCPOA) on April 2, 2015, and finalized the JCPOA on July 14, 2015. JCPOA Status On May 8, 2018, President Donald Trump announced that the United States would no longer participate in the JCPOA. The United States subsequently reimposed sanctions that had been suspended pursuant to the agreement. (For more information about the Trump Administration's JCPOA policy, see Appendix D .) The U.S. withdrawal attracted broad criticism among the other parties to the JCPOA, which states that the P5+1 and Iran "commit to implement" the agreement "in good faith and in a constructive atmosphere, based on mutual respect, and to refrain from any action inconsistent with the letter, spirit and intent of this JCPOA that would undermine its successful implementation." Whether the U.S. withdrawal violates UN Security Council Resolution 2231 is unclear; U.S. officials have argued that the JCPOA is not legally binding, but a European Union official told CRS in a November 30, 2016, email that "the commitments under the JCPOA have been given legally binding effect through UNSC Resolution 2231 (2015)." Following the initial reactions to the U.S. exit from the accord, Iran and the other parties began negotiations on concrete steps that would continue to provide Iran with the economic benefits of the JCPOA. On May 16, 2018, in an apparent effort to meet Iran's demands for remaining in the agreement, the EU announced "practical measures" for continued implementation of the JCPOA, including the following: maintaining and deepening economic relations with Iran; the continued sale of Iran's oil and gas condensate petroleum products and petrochemicals and related transfers; effective banking transactions with Iran; continued sea, land, air, and rail transportation relations with Iran; provision of export credit and special provisions in financial banking to facilitate economic and financial cooperation and trade and investment; further memoranda of understanding and contracts between European companies and Iranian counterparts; further investments in Iran; the protection of European Union economic operators and ensuring legal certainty; and further development of a transparent, rules-based business environment in Iran. Several E3 officials asserted in a November 2, 2018, statement with EU High Representative for Foreign Affairs and Security Policy Federica Mogherini that [i]t is our aim to protect European economic operators engaged in legitimate business with Iran…. As parties to the JCPoA, we have committed to work on, inter alia, the preservation and maintenance of effective financial channels with Iran, and the continuation of Iran's export of oil and gas. On January 31, 2019, France, Germany, and the United Kingdom, announced the creation of "a Special Purpose Vehicle aimed at facilitating legitimate trade between European economic operators and Iran." Called the Instrument for Supporting Trade Exchanges (INSTEX SAS), the vehicle "will support legitimate European trade with Iran, focusing initially on the sectors most essential to the Iranian population—such as pharmaceutical, medical devices and agri-food goods," according to the January 31 announcement. It added that the E3 should reaffirm that its "efforts to preserve the economic provisions of the JCPOA are conditioned upon Iran's full implementation of its nuclear-related commitments, including full and timely cooperation with the IAEA." In a May 9 statement with Mogherini, the E3 Foreign Ministers responded to an Iranian announcement the previous day that Tehran would stop performing some of its JCPOA commitments. "We remain fully committed to the preservation and full implementation of the JCPOA," the statement explained, adding that the participants "strongly urge Iran to continue to implement its [JCPOA] commitments … and to refrain from any escalatory steps." The statement also reiterated the participants' determination "to continue pursuing efforts to enable the continuation of legitimate trade with Iran." Iranian Reaction Iranian officials have repeatedly stated that Tehran would fulfill its JCPOA commitments as long as the United States did, and they repeatedly have rejected renegotiating the JCPOA or negotiating a new agreement, such as the sort described by U.S. officials. Amano told the IAEA Board of Governors on March 4, 2019, that "Iran is implementing its nuclear-related [JCPOA] commitments." Iran "is fully prepared to return to the pre-JCPOA situation or even [to conditions] more robust than that if the US reneges on its promises to the extent that the JCPOA's continuation harms our national interests," Iranian Foreign Minister Javad Zarif asserted the previous month. Deputy Foreign Minister Seyed Abbas Araqchi claimed that Iran "will be able to reach the industrial enrichment phase in less than two years"; other Iranian officials have asserted that the country can rapidly reconstitute its fissile material production capability. "Iran will remain committed to the nuclear deal if the remaining signatories to the JCPOA abide by their commitments," Araqchi stated in late January 2019. Atomic Energy Organization of Iran (AEOI) spokesperson Behrouz Kamalvandi stated about two weeks later that, should the remaining JCPOA parties fail to fulfill their JCPOA obligations, the AEOI will accelerate the nuclear program with "dazzling speed." Iranian officials have described a number of possible responses to a U.S. decision to reimpose U.S. sanctions, including resuming uranium enrichment, referring the matter to the Joint Commission, decreasing cooperation with the IAEA, and withdrawing from the NPT. These responses do not include the possible Iranian development of nuclear weapons, Iranian officials have said. Asked on April 21, 2018, if Iran will continue to meet its JCPOA obligations if all P5+1 parties except for the United States continue to uphold their obligations, Zarif replied, "I believe that's highly unlikely." He added that it is important for Iran receive the benefits of the agreement. And there is no way that Iran would do a one-sided implementation of the agreement. And it would require a major effort because right now, with the United States ostensibly in the agreement, a lot has been lacking in terms of Iran benefiting from the deal. Following Trump's May 2018 announcement, Iranian officials rejected negotiating any new agreements. In a May 10, 2018, letter to U.N. Secretary General António Guterres, Foreign Minister Zarif wrote that "[i]f JCPOA is to survive, the remaining JCPOA Participants and the international community need to fully ensure that Iran is compensated unconditionally through appropriate national, regional and global measures." He added that Iran has decided to resort to the JCPOA mechanism in good faith to find solutions in order to rectify the United States' multiple cases of significant non-performance and its unlawful withdrawal, and to determine whether and how the remaining JCPOA Participants and other economic partners can ensure the full benefits that the Iranian people are entitled to derive from this global diplomatic achievement. Supreme Leader Ayatollah Ali Khamene'i stated on May 23 that Iran will continue to participate in the JCPOA only if Europe provides "concrete guarantees" that it maintains Iran's existing revenue stream from oil sales to the EU countries. He also demanded that Europe not raise the issues of Iran's missiles programs or regional influence, adding that "Iran has the right to resume its nuclear activities." President Rouhani expressed a similar view in a July 4 speech. According to Iranian officials, Tehran has begun preparations for expanding its uranium enrichment program, albeit within the parameters of the JCPOA for the time being. AEOI spokesperson Kamalvandi stated on June 5, 2018, that the organization "will start the process of boosting the capacity of the country's uranium enrichment," by increasing Iran's capacity to produce uranium hexafluoride. On June 27, Iran's official news agency announced that Iran has resumed operations at its uranium conversion facility, which Iran has used to produce this material. Kamalvandi explained that Iran would begin the process of "manufacturing and assembly of centrifuge rotors," which are critical components of such machines. Iran "will begin building a centrifuge rotor plant," he noted. In addition, AEOI head Ali Akbar Salehi stated that Tehran will begin using an "advanced centrifuge assembly centre in the Natanz nuclear facility," which Iran had not disclosed publicly. Kamalvandi noted that Iran would continue to operate within the constraints of its JCPOA commitments, but added that, should the JCPOA collapse, Iran would produce centrifuges beyond those constraints. As noted, Iran remains subject to its obligations pursuant to the JCPOA and Resolution 2231 and could be subject to the reimposition of multilateral sanctions if Tehran violates these obligations. Several multilateral meetings since the U.S. withdrawal have not produced a firm Iranian commitment to the JCPOA. At Iran's request, the Joint Commission held meetings, attended by all of the JCPOA parties except for the United States, on May 25 and July 6. At the conclusion of the July 6 meeting, the Joint Commission participants reaffirmed their commitment to the EU "practical measures" enumerated above. However, President Rouhani reacted to the pledges by saying that "[u]nfortunately, the EU's package of proposals lacked an operational solution and a specific method for cooperation." Reacting to the January 2019 E3 announcement of the Special Purpose Vehicle, Foreign Minister Zarif warned on February 17, 2019, that "INSTEX falls short of the commitments by the E3 to 'save' the JCPOA," adding that "Europe needs to be willing to get wet if it wants to swim against the dangerous tide of U.S. unilateralism." In May 8 letters to the other JCPOA participant governments, Iran announced that, as of that day, Tehran had stopped "some of its measures under the JCPOA," though the government emphasized that it was not withdrawing from the agreement. Specifically, Iran will not transfer LEU or heavy water out of the country in order to maintain those stockpiles below the JCPOA-mandated limits described above. The Iranian government has stated that it will resume full compliance with the JCPOA if the remaining JCPOA participants agree during a 60-day period following the May 8 announcement to meet Tehran's "main demands, specifically in the banking and oil sectors." Absent such an agreement, Iran will cease to accept any constraints on the amount of uranium-235 contained in any Iranian-produced enriched uranium. Iran may then also resume work on the Arak reactor according to the JCPOA-mandated design. Iran will "take other steps," should Tehran fail to reach an agreement with the remaining JCPOA participants during a 60-day period to begin after Iran takes this second set of steps. Iran has also announced that Tehran "will show a strong and immediate response" if the remaining JCPOA participants respond to the May 8 action by referring Iran's case to the Security Council or imposing additional sanctions on Iran. Appendix D. Trump Administration Joint Cooperative Plan of Action Policy On May 8, 2018, President Donald Trump announced that the United States would no longer participate in the Joint Cooperative Plan of Action (JCPOA) and would reimpose U.S. sanctions that had been suspended pursuant to the agreement. President Trump ordered Secretary of State Michael Pompeo to "take all appropriate steps to cease the participation of the United States in the JCPOA," and, along with Secretary of the Treasury Steven Mnuchin, to immediately "begin taking steps to reimpose all United States sanctions lifted or waived in connection" with the agreement. The United States has notified the other P5+1 states that it will no longer attend meetings of the Joint Commission, the working group concerning the Arak reactor, or the procurement working group, all of which were established pursuant to the JCPOA. Secretary Pompeo detailed a new U.S. approach with respect to Iran during a May 21, 2018, speech as applying "unprecedented financial pressure on the Iranian regime," working "with the Department of Defense and our regional allies to deter Iranian aggression," and advocating "tirelessly for the Iranian people." He asserted that, in exchange for "major changes" in Iran's behavior, the United States is "prepared to end the principal components of every one of our sanctions against the regime …, re-establish full diplomatic and commercial relationships with Iran ..., [a]nd support the modernization and reintegration of the Iranian economy into the international economic system." Pompeo listed a number of essential elements for any new agreement: First, Iran must declare to the IAEA a full account of the prior military dimensions of its nuclear program, and permanently and verifiably abandon such work in perpetuity. Second, Iran must stop enrichment and never pursue plutonium reprocessing. This includes closing its heavy-water reactor. Third, Iran must also provide the IAEA with unqualified access to all sites throughout the entire country. Iran must end its proliferation of ballistic missiles and halt further launching or development of nuclear-capable missile systems. Iran must release all U.S. citizens, as well as citizens of our partners and allies, each of them detained on spurious charges. Iran must end support to Middle East terrorist groups, including Lebanese Hizballah, Hamas, and the Palestinian Islamic Jihad. Iran must respect the sovereignty of the Iraqi Government and permit the disarming, demobilization, and reintegration of Shia militias. Iran must also end its military support for the Houthi militia and work toward a peaceful political settlement in Yemen. Iran must withdraw all forces under Iranian command throughout the entirety of Syria. Iran, too, must end support for the Taliban and other terrorists in Afghanistan and the region, and cease harboring senior al-Qaida leaders. Iran, too, must end the IRGC [Islamic Revolutionary Guard Corps] Qods Force's support for terrorists and militant partners around the world. And too, Iran must end its threatening behavior against its neighbors—many of whom are U.S. allies. This certainly includes its threats to destroy Israel, and its firing of missiles into Saudi Arabia and the United Arab Emirates. It also includes threats to international shipping and destructive ... cyberattacks. On May 21, 2018, State Department Director for Policy Planning Hook stated that "the plan is to continue working with our allies, as we have been over the last few months, to create a new security architecture." During a July 2, 2018, press briefing, Hook explained that following Trump's May 8, 2018, announcement, Secretaries Pompeo and Mnuchin "decided to create joint teams of senior officials to visit every region of the world. These teams were launched on June 4." The United States has reimposed sanctions on Iran in two tranches: the first in May 2018 and the second in November 2018. The Administration waived sanctions in November 2018 for non-U.S. persons participating in a number of Iranian nuclear activities: the JCPOA-mandated projects at Arak, Bushehr, and Fordow; transfers from Iran of enriched uranium for the purpose of preventing Iran's low-enriched uranium (LEU) stockpile from exceeding 300 kilograms and exports of natural uranium to Iran in exchange for such transfers; authorized transfers to Iran of LEU fuel for the Tehran Research Reactor; transfers from Iran of "nuclear fuel scrap," which "cannot be fabricated into fuel plates" for the reactor; transfers from Iran of spent nuclear reactor fuel; and storage of Iranian heavy water exported before November 5, 2018. In May 2019, the United States renewed waivers for these activities except for the transfers of LEU out of Iran, the "storage for Iran of heavy water" that Tehran has "produced in excess of current limits," and "assistance to expand" the Bushehr plant "beyond the existing reactor unit." On February 14, 2019, Vice President Michael Pence called on the E3 "to withdraw from the Iran nuclear deal." Trump Administration officials continue to insist that the current U.S. policy is not "regime change" in Tehran. Instead, they describe a policy that threatens the Iranian government with the prospect of sanctions-induced political unrest and economic collapse, should Tehran refuse to make certain concessions. State Department Director for Policy Planning Brian Hook explained in a November 2, 2018, press briefing that the reimposition of sanctions is "designed to do two things: deny the regime the revenue it needs to fund violent wars abroad, and also to change the cost-benefit analysis in our favor so that Iran decides to come back to the negotiating table." Hook told National Public Radio on November 9, 2018 that [w]e're not talking about regime change. The future of this regime is up to the Iranian people. What we have been looking for is a change in their behavior, and we are very hopeful that our campaign of maximum economic pressure on this regime is going to help accelerate the path to reform that not only we want but the Iranian people want. Assistant Secretary of State Christopher Ford explained in a December 18, 2018, speech that the U.S. reimposition of sanctions is "setting the stage for a diplomatic process that can resolve the crisis created by Iran's extraordinary range of malign acts in the Middle East and beyond." Trump Administration officials have threatened Iran with possible military action, should Tehran violate its JCOPA nuclear commitments. Pompeo himself stated, during a June 22 television interview, that if Iran were to "ramp up" work on its nuclear program, "the wrath of the entire world will fall upon" the government, explaining that "wrath" referred to "moral opprobrium and economic power," rather than military action. Several months later, Pompeo wrote that [e]conomic pressure is one part of the U.S. campaign. Deterrence is another. President Trump believes in clear measures to discourage Iran from restarting its nuclear program or continuing its other malign activities. With Iran and other countries, he has made it clear that he will not tolerate attempts to bully the United States; he will punch back hard if U.S. security is threatened. Chairman Kim has felt this pressure, and he would never have come to the table in Singapore without it. The president's own public communications themselves function as a deterrence mechanism. The all-caps tweet he directed at Iranian President Hassan Rouhani in July, in which he instructed Iran to stop threatening the United States, was informed by a strategic calculation: the Iranian regime understands and fears the United States' military might. In September, militias in Iraq launched life-threatening rocket attacks against the U.S. embassy compound in Baghdad and the U.S. consulate in Basra. Iran did not stop these attacks, which were carried out by proxies it has supported with funding, training, and weapons. The United States will hold the regime in Tehran accountable for any attack that results in injury to our personnel or damage to our facilities. America will respond swiftly and decisively in defense of American lives. Appendix E. Possible Military Dimensions of Iran's Nuclear Program Then-International Atomic Energy Agency (IAEA) Director-General Mohamed ElBaradei told the agency's Board of Governors on June 2, 2008, that questions regarding "possible military dimensions" to Iran's nuclear program constituted the "one remaining major issue" concerning the IAEA's investigation of the program. A November 2011 report by current IAEA Director-General Yukiya Amano to the IAEA board contains the most detailed account to date of the IAEA's evidence regarding Iran's suspected nuclear weapons-related activities. Unless otherwise noted, this appendix is based on Amano's November 2011 report. The IAEA has "credible" information that Iran has carried out activities "relevant to the development of a nuclear explosive device." Although some of these activities have civilian applications, "others are specific to nuclear weapons," the report notes. Most of these activities were conducted before the end of 2003, though some may have continued. The Iranian government managed these activities via a program structure that included "senior Iranian figures." Amano's report contains a detailed description of the program's structure, which was established in the late 1980s. The program's activities were managed by an institution called the Physics Research Center and were overseen by an Iranian Ministry of Defense entity. About a decade later, the center's activities were consolidated under a new entity called the AMAD Plan. After the Iranian regime halted the AMAD Plan's work in 2003, "staff remained in place to record and document the achievements of their respective projects," according to information provided to the IAEA by unnamed governments. Later, "equipment and work places were either cleaned or disposed of so that there would be little to identify the sensitive nature of the work which had been undertaken." The IAEA has "other information" from governments that "indicates that some activities previously carried out under the AMAD Plan were resumed later." Some of these activities "would be highly relevant to a nuclear weapon programme." A December 2015 report from Amano assesses that although s ome Iranian nuclear weapons-related activities " took place after 2003," these activities "were n ot part of a coordinated effort. " The IAEA "has no credible indications of activities in Iran relevant to the development of a nuclear explosive device after 2009," the report explains. The IAEA has information that the AMAD Plan either obtained or attempted to obtain dual-use "equipment, materials and services which ... would be useful in the development of a nuclear explosive device." In addition, the program may have conducted studies on uranium conversion, missile reentry vehicles for delivering nuclear warheads, and conventional explosives used in nuclear weapons. Nuclear Explosive Device Components The IAEA has information indicating that Iran may have conducted work on components for nuclear weapons. Iran possesses a document "describing the procedures" for reducing uranium hexafluoride to uranium metal, as well as "machining ... enriched uranium metal into hemispheres," which are "components of nuclear weapons." Tehran has previously told the IAEA that it was offered equipment for casting uranium but never actually received it. Moreover, a member of a clandestine nuclear supply network run by former Pakistani official Abdul Qadeer Khan told the IAEA that Iran "had been provided with nuclear explosive design information." However, this information may not be sufficient to produce a nuclear weapon. (See " Nuclear Weapon Development Capabilities .") The IAEA has received information from an unnamed government that Iran carried out "preparatory work, not involving nuclear material, for the fabrication of natural and high enriched uranium metal components for a nuclear explosive device." As noted, the AMAD Plan may have conducted studies on conventional explosives used in nuclear weapons. Implosion-type nuclear explosive devices use conventional explosives to compress a core of highly enriched uranium or plutonium to start a nuclear chain reaction. Specifically, Iran developed detonators that have limited nonnuclear applications but also could be used in a nuclear explosive device. In addition, Tehran may have experimented with a multipoint initiation system, which could be used in conjunction with the detonators. Furthermore, Iran may have conducted high explosive testing, possibly in association with nuclear materials, at the Parchin military site (see below). Lastly, Iran may have worked on neutron initiators, which are used in implosion-type nuclear weapons. Reentry Vehicle As noted, the IAEA has assessed that the AMAD Plan may have conducted studies on missile reentry vehicles for delivering nuclear warheads. These efforts possibly included "engineering studies to examine" integrating a payload into the reentry vehicle of Iran's Shahab-3 ballistic missile. Although these activities "may be relevant to the development of a non-nuclear payload, they are highly relevant to a nuclear weapon programme." Tehran also may have conducted work on a "prototype firing system" that would enable a missile's nuclear payload "to explode both in the air above a target, or upon impact of the re-entry vehicle with the ground." Parchin Parchin is an Iranian military site. The Institute for Science and International Security described the complex in a 2004 report as "a huge site dedicated to the research, development, and production of ammunition, rockets, and high explosives," adding that the site "is owned by Iran's military industry and has hundreds of buildings and test sites." IAEA inspectors investigated the Parchin site in 2005 after receiving "information ... from a Member State in the early 2000s alleging that Iran was conducting high explosive testing, possibly in association with nuclear materials." Such testing could contribute to the development of implosion-type nuclear explosive devices. IAEA inspectors visited the site twice in 2005, but they "did not uncover anything of relevance." Parchin was not under IAEA safeguards. However, the IAEA requested that Tehran respond to information obtained from unnamed governments indicating that "Iran constructed a large explosives containment vessel" in 2000 at Parchin "in which to conduct hydrodynamic experiments." Such experiments are conducted to validate the design of an implosion-type nuclear weapon and are "strong indicators of possible weapon development." The IAEA has not publicly reported whether Iran actually conducted these experiments. The inspectors in 2005 did not visit the building that the IAEA identified as housing the containment vessel. The agency requested access to this building in February 2012, but Iran did not provide such access until September 2015. At that time, IAEA officials "did not observe a chamber or any associated equipment inside the building." Iranian officials told their IAEA counterparts in October 2015 that the building in question "had always been used for the storage of chemical material for the production of explosives," but the "information available" to the IAEA, "does not support Iran's statements on the purpose of the building." Other Issues The IAEA asked Tehran about other indications, some of which do not appear in Amano's November 2011 report, suggesting that the country may have pursued nuclear weapons. These include "information about a high level meeting in 1984 on reviving Iran's pre-revolution nuclear programme"; "the scope of a visit by officials" associated with Iran's Atomic Energy Organization "to a nuclear installation in Pakistan in 1987"; information on meetings in 1993 between Iranian officials and members of a clandestine procurement network run by former Pakistani official Khan; information about work done in 2000 that apparently related to reprocessing; Iranian scientists' mathematical research with nuclear weapons applications; and information indicating that Iran "may have planned and undertaken preparatory experimentation which would be useful were Iran to carry out a test of a nuclear explosive device." Appendix F. Iranian Centrifuge Workshops and Related Entities This appendix lists Iranian entities that appear to have manufactured centrifuges or related components, as well as those that appear to have conducted work closely related to these activities. The appendix excludes entities that have been identified as solely involved in procuring materials or components for Iran's centrifuge program. This list is not exhaustive, and some of the publicly available information about Iran's centrifuge workshops may be outdated. International Atomic Energy Agency (IAEA) inspectors had access to Iranian centrifuge workshops until early 2006, in order to verify the October 2003 agreement under which Iran suspended its enrichment program. However, the agency's knowledge of Iran's workshops deteriorated after Tehran ended this access in early 2006. Iran may have subsequently moved centrifuge-related work to other locations and likely built more such workshops. Tehran has provided the IAEA with access to some centrifuge workshops pursuant to the Joint Plan of Action and the Joint Comprehensive Plan of Action. The latter agreement requires Iran to declare specific types of equipment for producing certain centrifuge components, as well as the locations where such production takes place. Kalaye Electric U.N. Security Council Resolution 1737 describes Kalaye Electric, which is located in Tehran, as a "provider" to Iran's pilot centrifuge facility located at Natanz. According to an August 2008 Institute for Science and International Security (ISIS) report, Kalaye Electric, an Atomic Energy Organization of Iran (AEOI) entity, operates the country's centrifuge program, but the AEOI controls the program. A December 2011 European Union Council regulation describes several entities as current suppliers to Kalaye Electric, suggesting that the company was still involved in Iran's centrifuge program at that time. 7 th of Tir Resolution 1737 describes 7 th of Tir, located in Esfahan, as "directly involved" in Iran's nuclear program. This facility was involved in manufacturing centrifuge components, according to the ISIS report, which added that Iran moved "the key centrifuge manufacturing equipment and components to Natanz and other AEOI sites" when the IAEA began monitoring the 2003 suspension agreement. Whether and to what extent the facility is still involved in manufacturing centrifuge components is unknown, the report says. Farayand Technique Resolution 1737 describes this entity, which is located in Esfahan, as "involved in" Iran's centrifuge program. The facility was involved in "making and assembling" centrifuge components, according to the 2008 ISIS report. According to a 2010 European Council regulation, another entity, called the Iran Centrifuge Technology Company, "has taken over the activities of Farayand Technique," which include "manufactur[ing] uranium enrichment centrifuge parts." Iran Centrifuge Technology Company As noted, this entity, which is apparently located in Esfahan, took over "the activities of Farayand Technique," which have included "manufactur[ing] uranium enrichment centrifuge parts," according to the 2010 European Council regulation. Pars Trash Resolution 1737 describes this Tehran-based entity as "involved in" Iran's centrifuge program. According to the ISIS report, the company manufactured centrifuge components. The report does not say whether Pars Trash is still involved in Iran's centrifuge program. Kaveh Cutting Tools Company This entity, according to the 2008 ISIS report, manufactured centrifuge components. The company is "part of" Khorasan Metallurgy Industries, the ISIS report says. Both of these entities are located in Mashad. Khorasan Metallurgy Industries is "involved in the production of centrifuge components," according to the 2010 European Council regulation. Khorasan Metallurgy Industries This entity, which is located in Mashad, has been "involved in the production of centrifuge components," according to the 2010 European Council regulation. Sanam Electronic Industry Group Located in Tehran, this entity was, according to ISIS, "involved in making centrifuge components." Abzar Boresh Kaveh Company U.N. Security Council Resolution 1803 describes this company as "[i]nvolved in the production of centrifuge components." Parto Sanat Company The 2010 European Council regulation describes this company, located in Tehran, as a "[m]anufacturer of frequency changers ... capable of developing/modifying imported foreign frequency changers in a way that makes them usable in gas centrifuge enrichment." Eyvaz Technic The 2011 European Council regulation states that, as recently as 2011, this Tehran-based company supplied Iran's Natanz and Fordow centrifuge facilities with equipment relevant to centrifuge operations. Ghani Sazi Uranium Company According to the 2011 European Council regulation, this company, which is located in Tehran, had "production contracts" with Kalaye Electric and Iran Centrifuge Technology Company. Iran Pooya The 2011 European Council regulation describes this Tehran-based entity as "a major manufacturer of aluminium cylinders for centrifuges whose customers" included the AEOI and Iran Centrifuge Technology Company. Mohandesi Toseh Sokht Atomi Company The 2011 European Council regulation describes this company, located in Tehran, as "contracted to" Kalaye Electric "to provide design and engineering services across the nuclear fuel cycle." Saman Nasb Zayendeh Rood The 2011 European Council regulation describes this company, located in Esfahan, as a "[c]onstruction contractor that has installed piping and associated support equipment at the uranium enrichment site at Natanz." The company "has dealt specifically with centrifuge piping," according to the regulation. Jelvesazan Company This company, located in Esfahan, was a possible supplier of vacuum pumps to the Iran Centrifuge Technology Company, according to a December 2012 European Council regulation. Iran Aluminium Company According to the December 2012 European Council regulation, this company, located in Arak, was a supplier to the Iran Centrifuge Technology Company as of mid-2012. Simatec Development Company The December 2012 European Council regulation identified this company, apparently located in Tehran, as a supplier of inverters for centrifuges to the Kalaye Electric Company. Sharif University of Technology This university, located in Tehran, has provided laboratories for use by the entity Kalaye Electric Company and the Iran Centrifuge Technology Company, according to the December 2012 European Council regulation. Zirconium Production Plant A 2012 report from the AEOI identified this plant, located in Esfahan, as a "provider of pipes and aluminum sheets used in different parts of centrifuge machines." Aluminat This Tehran-based company had a contract in 2012 to supply aluminum to the Iran Centrifuge Technology Company, according to the December 2012 European Council regulation. Pishro Systems Research Company This company, according to a 2013 State Department announcement, was "responsible for research and development efforts across the breadth of Iran's nuclear program," including Iran's enrichment program. The company "likely has or will have a facility" in Tehran, the State Department said. Fulmen Group This company "was involved in procuring goods" and installing "electrical equipment" for Iran's Fordow enrichment facility prior to 2009, according to the State Department and the European Union. The company also worked with Kalaye Electric "on the construction of elements of the Natanz Uranium Enrichment Plant." Appendix G. Post-2003 Suppliers to Iran's Uranium Enrichment Program Iran has obtained components, expertise, and material for its nuclear program from a variety of foreign sources. Tehran sought assistance for the program from the Russian and Chinese governments, but it also obtained relevant components, expertise, and material via deceptive procurement techniques. Perhaps Iran's best-known source was a clandestine procurement network run by former Pakistani official Abdul Qadeer Khan. This network began supplying Iran's centrifuge program in 1987, but U.S. and Pakistani officials have characterized the network as defunct since Pakistan publicly revealed the network in early 2004. It is worth noting that, according to former Deputy Director General of the International Atomic Energy Agency (IAEA) Olli Heinonen, the IAEA has not determined the source of material that Iran obtained for its advanced centrifuges. (CRS has not found additional information on this subject.) Methodology Because the original Khan network appears to be defunct, this appendix focuses on post-2003 suppliers to Iran's enrichment program. To obtain the information for this appendix, CRS reviewed official U.S. government reports, as well as lists of entities sanctioned by the United States and the European Union since early 2004. CRS also reviewed public information from the Department of Justice, reports from a U.N. Panel of Experts, and selected nongovernmental reports. To identify suppliers germane to this appendix, CRS excluded Iranian entities or nationals, Iranian ships under foreign flags, and entities associated with the Khan network. This methodology has limitations. Official reports generally do not provide enough information to identify specific suppliers to Iran's enrichment program and Federal Register announcements of the imposition of sanctions generally do not explain the specific transactions that warranted the sanctions. Even if official reports do identify suppliers to Iran's nuclear program, they often do not say whether those entities were supplying Iran's enrichment program. For example, an October 2008 Justice Department fact sheet stated that the sales director of a California-based corporation attempted to illegally export to Iran "machinery and software to measure the tensile strength of steel," explaining that these items "can make a contribution to nuclear activities of concern." The fact sheet, however, did not provide additional information, and neither 2007 testimony from a Department of Commerce official nor a 2008 Commerce Department announcement explained whether the exports were intended for Iran's enrichment program. Similarly, a 2008 report from the Czech Republic's Security Information Service stated that an Iranian company "subject to sanctions because of its involvement in the Iranian nuclear program" attempted to acquire "specific machinery" from a Czech supplier, but the report did not specify further. Suppliers to Iran's Enrichment Program The information reviewed for this appendix indicates that Iranian-owned entities were using deceptive means in attempts to acquire enrichment technology from foreign entities. However, the sources described above contain no evidence that foreign governments are currently supplying Iran's enrichment program. According to a 2009 State Department report, "all major suppliers, apart from Russia which is providing assistance to Iran's Bushehr Nuclear Power Plant, have agreed not to provide nuclear technology to Iran." In addition, State Department reports covering countries' compliance with international nonproliferation agreements between 2004 and 2010 indicate that the Chinese government is not involved in supplying Iran's suspected nuclear weapons program. Chinese Entities Robert J. Einhorn, then-State Department Special Advisor for Nonproliferation and Arms Control, stated in March 2011 that the United States continued "to have concerns about the transfer of proliferation-sensitive equipment and materials to Iran by Chinese companies." Similarly, the State Department compliance reports mentioned above indicate that unspecified non-Chinese entities have attempted to acquire "nuclear-related" materials and equipment from Chinese entities. Furthermore, a CIA report covering 2007 stated that "private Chinese businesses continue to sell materials, manufacturing equipment, and components suitable for use in ballistic missile, chemical weapon and nuclear weapon programs to North Korea, Iran and Pakistan." The report did not specify further. It is worth noting that Chinese entities may have supplied Iran with enrichment-related equipment obtained from Western suppliers. According to court documents made public in July 2012, an Iranian national attempted to obtain U.S.-origin components for Iran's enrichment program using entities in China and the Philippines. More recently, a Chinese citizen pleaded guilty in December 2015 to exporting U.S.-origin components used for uranium enrichment to Iranian entities via China. Other Suppliers Iran has reportedly established front companies in Turkey in order to obtain nuclear-related items. Notably, Turkish entities were involved with the Khan network. Iranian entities have also attempted to obtain nuclear-related items from companies in the Czech Republic, according to reports from that government's Security Information Service. Iran has also attempted to obtain enrichment-related equipment from U.S. suppliers. For example, according to a January 2012 Justice Department fact sheet, a man was sentenced in 2010 for attempting in March 2009 to export pressure transducers, which he had purchased in the United States, to Iran via Canada and the United Arab Emirates. "Pressure transducers have applications in the production of enriched uranium," according to the fact sheet. Also, the Justice Department announced in January 2016 that a Chinese citizen was sentenced in the United States for exporting U.S.-origin pressure transducers to Iran from 2009 to 2012.  In addition, a California-based firm exported "vacuum pumps and pump-related equipment to Iran through a free trade zone located in the United Arab Emirates [UAE]" between December 2007 and November 2008. This equipment has "a number of applications, including in the enrichment of uranium," according to the Justice Department fact sheet. In July 2013, an Iranian national pleaded guilty to arranging the illegal export of carbon fiber in 2008 to an Iranian entity. The individuals obtained the material from a U.S. supplier and shipped it to Iran via Europe and the UAE. Carbon fiber "has nuclear applications in uranium enrichment as well applications in missiles," according to an October 2014 Justice Department fact sheet. Declassified documents from the Canada Services Border Agency state that Iranian entities were also attempting to acquire items from Canada for Iran's nuclear program, though the documents do not specifically mention Tehran's enrichment program. The documents also state that "Iranian procurement agents have ... been able to export items [from Canada]," international sanctions notwithstanding. The documents, however, do not specify whether exported items were destined for Iran's nuclear program. Moreover, as noted, court documents made public in July 2012 state that an Iranian national attempted to obtain U.S.-origin components via Canada for Iran's enrichment program. Entities in the UAE were part of the Khan network and have been cited as shippers for enrichment-related technology to Iran. Einhorn described the UAE in March 2011 as a "trans-shipment hub for Iran," but added that the UAE "has also taken strong steps in recent months to curtail illicit Iranian activities." A 2011 European Council regulation identified two UAE entities, Modern Technologies FZC and Qualitest FZE, as "[i]nvolved in procurement of components for [the] Iranian nuclear programme," although the regulation did not specify whether the components were for uranium enrichment.

Summary: Iran's nuclear program began during the 1950s. The United States has expressed concern since the mid-1970s that Tehran might develop nuclear weapons. Iran's construction of gas centrifuge uranium enrichment facilities is currently the main source of proliferation concern. Gas centrifuges can produce both low-enriched uranium (LEU), which can be used in nuclear power reactors, and weapons-grade highly enriched uranium (HEU), which is one of the two types of fissile material used in nuclear weapons. Is Iran Capable of Building Nuclear Weapons? The United States has assessed that Tehran possesses the technological and industrial capacity to produce nuclear weapons. But Iran has not yet mastered all of the necessary technologies for building such weapons. Whether Iran has a viable design for a nuclear weapon is unclear. A National Intelligence Estimate made public in 2007 assessed that Tehran "halted its nuclear weapons program" in 2003. The estimate, however, also assessed that Tehran is "keeping open the option to develop nuclear weapons" and that any decision to end a nuclear weapons program is "inherently reversible." U.S. intelligence officials have reaffirmed this judgment on several occasions. Obtaining fissile material is widely regarded as the most difficult task in building nuclear weapons. As of January 2014, Iran had produced an amount of LEU containing up to 5% uranium-235, which, if further enriched, could theoretically have produced enough HEU for as many as eight nuclear weapons. Iran had also produced LEU containing nearly 20% uranium-235; the total amount of this LEU, if it had been in the form of uranium hexafluoride and further enriched, would have been sufficient for a nuclear weapon.. After the Joint Plan of Action, which Tehran concluded with China, France, Germany, Russia, the United Kingdom, and the United States (collectively known as the "P5+1"), went into effect in January 2014, Iran either converted much of its LEU containing nearly 20% uranium-235 for use as fuel in a research reactor located in Tehran, or prepared it for that purpose. Iran has diluted the rest of that stockpile so that it contained no more than 5% uranium-235. In addition, Tehran has implemented various restrictions on, and provided the IAEA with additional information about, its nuclear program pursuant to the July 2015 Joint Comprehensive Plan of Action (JCPOA), which Tehran concluded with the P5+1. Although Iran claims that its nuclear program is exclusively for peaceful purposes, the program has generated considerable concern that Tehran is pursuing a nuclear weapons program. The U.N. Security Council responded to Iran's refusal to suspend work on its uranium enrichment program by adopting several resolutions that imposed sanctions on Tehran. Despite evidence that sanctions and other forms of pressure have slowed the program, Iran continued to enrich uranium, install additional centrifuges, and conduct research on new types of centrifuges. Tehran has also worked on a heavy-water reactor, which was a proliferation concern because its spent fuel would have contained plutonium—the other type of fissile material used in nuclear weapons. However, plutonium must be separated from spent fuel—a procedure called "reprocessing." Iran has said that it will not engage in reprocessing. Who Is Monitoring Iran's Nuclear Program? The International Atomic Energy Agency (IAEA) monitors Iran's nuclear facilities and has verified that Tehran's declared nuclear facilities and materials have not been diverted for military purposes. The agency has also verified that Iran's compliance with the JCPOA. On the JCPOA's Implementation Day, which took place on January 16, 2016, all of the previous Security Council resolutions' requirements were terminated. The nuclear Nonproliferation Treaty (NPT) and U.N. Security Council Resolution 2231, which the council adopted on July 20, 2015, compose the current legal framework governing Iran's nuclear program. Iran has continued to comply with the JCPOA and Resolution 2231. Iran and the IAEA agreed in 2007 on a work plan to clarify outstanding questions regarding Tehran's nuclear program, most of which concerned possible Iranian procurement activities and research directly applicable to nuclear weapons development. A December 2015 report to the IAEA Board of Governors from agency Director-General Yukiya Amano contains the IAEA's "final assessment on the resolution" of these outstanding issues. How Soon Could Iran Produce a Nuclear Weapon? Then-Under Secretary of State for Political Affairs Wendy Sherman explained during an October 2013 hearing of the Senate Committee on Foreign Relations that Iran would need as much as one year to produce a nuclear weapon if the government decided to do so. At the time, Tehran would have needed two to three months to produce enough weapons-grade HEU for a nuclear weapon. Iran's compliance with the JCPOA has increased that time frame to one year, according to U.S. officials. These estimates apparently assume that Iran would use its declared nuclear facilities to produce fissile material for a weapon. However, Tehran would probably use covert facilities for this purpose; Iranian efforts to produce fissile material for nuclear weapons by using its known nuclear facilities would almost certainly be detected by the IAEA.