The nuclear program of Iran consists of an extensive infrastructure of research sites, uranium mines, research reactors, uranium processing facilities, enrichment sites, the Bushehr Nuclear Power Plant (the country’s sole operational power reactor, currently expanding with two additional units), and the developing Darkhovin Nuclear Power Plant in Khuzestan. The program’s research capabilities are anchored by several facilities, most notably the Tehran Research Reactor and the heavy water reactor at Khondab. Iran's uranium processing infrastructure is centered in Isfahan, which serves as a hub for conversion and fuel fabrication, while primary enrichment activities are conducted at Natanz, Fordow, and within the Isfahan complex.
Iran’s stated objective is a self-sufficient nuclear energy cycle to diversify its power grid and produce medical radioisotopes, citing a legal right to peaceful technology under the Non-Proliferation Treaty (NPT). While viewed as a cornerstone of Iranian technological nationalism, the program has been the subject of a decades-long diplomatic and military standoff, particularly with the United States and Israel, culminating in large-scale conflicts in 2025 and 2026.
The program began in 1957 as part of the US-led Atoms for Peace initiative and expanded significantly during the 1970s under the Pahlavi era, which saw the start of the Bushehr project with Western assistance. Following the 1979 Iranian Revolution, the program was initially deprioritized but was revived in the late 1980s.
During the 1990s and early 2000s, Iran developed several undeclared sites, which were identified by international observers in 2002 and 2009. Following the collapse of negotiations with the EU-3 in 2005, the International Atomic Energy Agency (IAEA) Board of Governors found Iran in non-compliance with its NPT safeguards agreement,Resolution 1696 (2006) leading the United Nations Security Council (UNSC) to pass a series of resolutions between 2006 and 2010 demanding a suspension of Iran's enrichment-related activities and targeting Iran’s banking, trade, and energy sectors. While Western intelligence agencies assessed that a dedicated weaponization project, the AMAD Project, was discontinued in 2003, Iran's ongoing enrichment activities led to a decades-long cycle of international sanctions and a sustained campaign of covert sabotage, including the 2009 Stuxnet cyberattack, multiple assassinations of Iranian nuclear scientists, and strikes on facilities in 2020 and 2021, which Iran characterized as "nuclear terrorism."
In 2015, the Joint Comprehensive Plan of Action (JCPOA) was signed by Iran, China, France, Russia, the United Kingdom, the US, and Germany, under which Iran agreed to strict enrichment limits and extensive international monitoring at its nuclear facilities in exchange for sanctions relief. Although the JCPOA briefly stabilized the situation, this period of oversight ended in 2018 following the unilateral withdrawal of the United States and the subsequent "Maximum Pressure" campaign. In response to the US withdrawal, and citing ongoing acts of US and Israeli sabotage, Iran incrementally reduced its compliance and raised enrichment levels to 60%, a move the Iranian government characterized as diplomatic leverage to secure the removal of reinstated sanctions. In August 2025, France, Germany, and the UK triggered the snapback mechanism, reinstating UN sanctions; that October, Iran, Russia, and China declared they viewed JCPOA terminated and the UN sanctions legally void.
The standoff escalated into direct military conflict with the Twelve-Day War in June 2025 and a larger joint U.S.-Israeli campaign in February 2026 targeting nuclear and ballistic missile infrastructure. These strikes, which included the assassination of high-ranking Iranian officials, were justified by the U.S. and Israel as preemptive measures to prevent a nuclear breakout. Following a Pakistan-mediated ceasefire in April 2026, the parties entered high-level negotiations in Islamabad. However, a lasting settlement remains elusive; while the U.S. has demanded a permanent end to all uranium enrichment, Iran maintains its legal right to a civilian program. Analysts remain divided on the long-term impact of the conflict, debating whether the physical damage has permanently delayed the program or instead incentivized a transition from nuclear latency to the pursuit of a completed deterrent.
History
Origins under the Shah (1950s–1970s)
Iran's nuclear program began under the rule of Shah Mohammad Reza Pahlavi, with support from the United States and Western Europe. In 1957, Iran and the US signed a civil nuclear cooperation agreement as part of President Dwight Eisenhower's Atoms for Peace program, leading to the construction of Iran's first nuclear research facility Tehran. In November 1967, the Tehran Research Reactor (TRR)—a 5 megawatt thermal light-water reactor—went critical, initially fueled with 93% highly enriched uranium (HEU) provided by the US. Iran became one of the original signatories of the NPT when it entered into force in March 1970, committing as a non-nuclear-weapon state not to pursue nuclear arms.
By the mid-1970s, the Shah expanded the program, citing the need for "alternative sources of fuel for the day when the oil reserves would be depleted." In 1974 he established the Atomic Energy Organization of Iran (AEOI) and announced plans to produce 23,000 megawatts of electricity from a network of nuclear power plants over 20 years. Contracts were signed with Western firms: Iran paid over $1 billion for a 10% stake in the French Eurodif consortium's uranium enrichment plant, and West Germany's Kraftwerk Union agreed to build two 1,200 MWe pressurized water reactors at Bushehr. Construction of the Bushehr Nuclear Power Plant began in 1975, and Iran also negotiated with France's Framatome to supply additional reactors. Plans were made for a full domestic nuclear fuel cycle, including uranium mining and fuel fabrication, with a new Nuclear Technology Center established at Isfahan.
Post-revolution revival and war impact (1979–1980s) This ambitious program slowed dramatically after the 1979 Islamic Revolution. The Shah was deposed and Iran's new leaders under Ayatollah Ruhollah Khomeini were initially hostile to nuclear technology, seeing it as a symbol of Western influence. Many ongoing nuclear projects were shelved or canceled. The Iran–Iraq War (1980–1988) derailed the nuclear program: resources were diverted to the war effort, and Iraq targeted Iran's nuclear infrastructure. The partially built Bushehr reactor site was bombed multiple times by Iraqi warplanes, and Siemens withdrew from the project, leaving the reactor shells heavily damaged. By the late 1980s, Iran's nuclear program had effectively been put on hold.
Secret expansion and weaponization efforts (1990s–2002) By the early 1990s, Iran's nuclear program accelerated on two parallel tracks: one overtly civilian and one covert. Openly, Iran continued working with Russia and China to build peaceful nuclear infrastructure. Bushehr's reactor project moved forward under Russian engineers (though plagued by delays until it finally came online in 2011), and China helped Iran with nuclear research and uranium mining expertise. Less transparently, Iran was building a secret enrichment capability and exploring technologies relevant to nuclear weapons, away from the eyes of inspectors.
Iran's covert procurement of enrichment technology bore fruit in the 1990s. Thousands of centrifuge components, tools, and technical drawings obtained from A.Q. Khan and the proliferation network were used to set up secret pilot enrichment workshops. Experiments with uranium hexafluoride gas were conducted in undeclared facilities in Tehran (such as the Kalaye Electric Company) in the late 1990s. In 2000, Iran completed a uranium conversion plant at Isfahan, based on a Chinese design, to produce uranium hexafluoride feedstock for enrichment. It also developed domestic sources of uranium: the Saghand mine in Yazd province (with Chinese assistance) and the Gchine mine and mill near the Gulf coast. The Gchine uranium mine became operational in 2004 and is now believed to have originally been part of a military-run nuclear effort, kept hidden from the IAEA until revealed in 2003. These steps gave Iran independent access to the raw materials and precursor processes for a weapons-capable nuclear fuel cycle.
In the late 1990s Iran launched a nuclear weapons research program, codenamed the AMAD Project, under the aegis of the Iranian Ministry of Defense. According to later IAEA findings, the AMAD Project (led by Mohsen Fakhrizadeh, a top nuclear scientist) aimed to design and build an arsenal of five nuclear warheads by the mid-2000s. Between 1999 and 2003, this secret program managed to illegally acquire warhead design (reportedly and possibly including an engineered Pakistan design from KRL– although Pakistan disputed this claim), conducting high-explosive tests and detonator development for an implosion-type bomb, manufacturing some nuclear weapon components with surrogate materials, and integrating a warhead design into Iran's Shahab-3 ballistic missile system. The main thing Amad lacked was fissile material, since Iran had not yet produced weapons-grade uranium or plutonium for a bomb core. Still, the scope of Amad demonstrated that Iran was exploring the bomb option in violation of its NPT obligations.
Throughout the 1990s, Iranian entities also received steady assistance from foreign sources. Some Russian and Chinese companies provided Iran with expertise and equipment for its nuclear program. For example, Chinese technicians conducted uranium exploration in Iran and allegedly supplied blueprints that aided Iran's construction of the Isfahan conversion facility. Iranians also gained know-how through Pakistan's academic exhanges (later becoming a loggerhead issue between Pakistan and the United States), and from academic exchanges abroad. That enabled Iran to secretly establish the critical facilities that could produce weapons-usable material: large uranium enrichment plants and a heavy-water reactor project.
By the early 2000s, two key clandestine facilities were nearing completion: a uranium enrichment center at Natanz (in central Iran), built to house thousands of centrifuges, and a heavy water production plant alongside a 40 MW heavy-water reactor (IR-40) near Arak. These facilities, which had been kept secret from the IAEA, were intended for ostensibly civilian purposes but had clear weapons potential. Enrichment at Natanz could yield high-enriched uranium for bombs, while the Arak reactor (once operational) could produce plutonium in its spent fuel, and the heavy water plant would supply the reactor's coolant. In August 2002, an exiled Iranian opposition group, the National Council of Resistance of Iran (NCRI), exposed the existence of Natanz and Arak. Satellite imagery soon confirmed construction at these sites. The revelation that Iran had built major nuclear facilities in secret, without required disclosure to the IAEA, ignited an international crisis and raised questions about the program's true aim.
Exposure and International Confrontation (2002–2013)
In late 2003, Iran was facing the prospect of censure and agreed to a degree of cooperation. In October 2003, Iran and the foreign ministers of Britain, France, and Germany (the "EU-3") struck the Tehran Agreement: Iran pledged to temporarily suspend all uranium enrichment and reprocessing activities, allow more intrusive inspections by signing the Additional Protocol, and clarify past nuclear work. This deal, reached just ahead of an IAEA Board of Governors deadline, was intended to build confidence while a longer-term solution was negotiated. However, Iran's cooperation was halting and incomplete.