Nuclear program of Iran
Iran's nuclear program, one of the most scrutinized in the world, has sparked intense international concern. While Iran asserts that its nuclear ambitions are purely for civilian purposes, including energy production, the country historically pursued the secretive AMAD nuclear weapons project. This has raised fears that Iran is moving closer to developing nuclear weapons, a prospect that has led to rising tensions, particularly with Israel, the United States, and European nations. The issue remains a critical flashpoint in the Middle East, with ongoing military and diplomatic confrontations. According to The New York Times in 2025, "If Iran is truly pursuing a nuclear weapon—which it officially denies—it is taking more time than any nuclear-armed nation in history."
Iran's nuclear program began in the 1950s under the Pahlavi dynasty with United States support. It expanded in the 1970s with plans for power reactors, paused after the 1979 Iranian Revolution, and resumed secretly during the 1980s Iran–Iraq War. Undeclared enrichment sites at Natanz and Arak were exposed in 2002, and Fordow, an underground fuel enrichment site, was revealed in 2009.
Iran's nuclear program has been a focal point of international scrutiny for decades. In 2003, Iran suspended its formal nuclear weapons program, and claims its program is for peaceful purposes only, yet analysts and the IAEA have refuted such claims. Iran was producing enriched uranium at 60% purity, and was accelerating its nuclear advancements by installing more advanced centrifuges. Analysts warn that these activities far exceed any plausible civilian purpose. Estimates suggest that Iran could produce enough weapons-grade uranium for one nuclear bomb within a week and accumulate enough for seven within a month, raising fears that its breakout time has shortened drastically. The destruction of Israel is frequently cited as one of several strategic objectives behind Iran's nuclear ambitions. Concerns include nuclear proliferation, nuclear terrorism, and increased support for terrorism and insurgency.
In response to Iran's nuclear program, the international community imposed sanctions that severely impacted its economy, restricting its oil exports and limiting access to global financial systems. Covert operations such as the Stuxnet cyberattack in 2010 sought to disrupt the program. In 2015, the Joint Comprehensive Plan of Action was signed, imposing strict limitations on Iran's nuclear program in exchange for sanctions relief. In 2018, the United States withdrew from the agreement, leading to re-imposed sanctions. Since then, Iran's nuclear program has expanded dramatically, with enriched uranium stockpiles exceeding JCPOA limits by tens of times, some nearing weapons-grade purity. In October 2023, an IAEA report estimated Iran had increased its uranium stockpile 22 times over the 2015 agreed JCPOA limit. According to the IAEA, Iran is "the only non-nuclear-weapon state to produce such material". In the last months of the Biden administration, new intelligence persuaded US officials that Iran was exploring a gun-type fission weapon, a cruder design that could enable Iran to manufacture a nuclear weapon, undeliverable by missile, in a matter of months. The US and Iran have engaged in bilateral negotiations since April 2025, aiming to curb Iran's program for sanctions relief, though Iran's leaders have refused to stop enriching uranium.
On 12 June 2025, the IAEA found Iran non-compliant with its nuclear obligations for the first time in 20 years. Iran retaliated by launching a new enrichment site and installing advanced centrifuges. One day later, Israel, which is not a party to the Non-Proliferation Treaty and is widely believed to possess nuclear weapons, launched the Iran–Israel war and coordinated strikes across Iran, targeting nuclear facilities and damaging Natanz and other sites. Eight days later, the United States bombed three Iranian nuclear sites.
On August 28, 2025, E3 members, France, Germany, and the United Kingdom, initiated the process of the snapback mechanism, stating that despite upholding their own commitments, since 2019 Iran had "increasingly and deliberately ceased performing its JCPOA commitments", including "the accumulation of a highly enriched uranium stockpile which lacks any credible civilian justification and is unprecedented for a state without a nuclear weapons program". On 28 September 2025, UN sanctions were officially reimposed on Iran.
On 24 December 2025, it was reported that in October 2025 Supreme Leader Ali Khamenei had authorised the development of miniaturised nuclear warheads for ballistic missiles.
Motivations
Iran's nuclear program is commonly viewed as serving several purposes, according to widely cited analyses. The program is seen as a means to destroy Israel or threaten its existence. The United States has maintained that a nuclear-capable Iran would likely use its capabilities to attempt the annihilation of Israel. It has also been argued that a nuclear-armed Iran would likely intensify its efforts to destroy Israel under the protection of a nuclear deterrent, resulting in catastrophic consequences.Iran's nuclear program is also believed to function as a tool to protect the Iranian regime and nation from foreign aggression and external dominance. It may also serve as an instrument of Iranian aggression and hegemony, projecting power in the region. Scholars argue that a nuclear-armed Iran could feel emboldened to increase its support for terrorism and insurgency, core elements of its strategy, while deterring retaliation through its newfound nuclear leverage. The potential transfer of nuclear technology or weapons to radical states and terrorist organizations heightens fears of nuclear terrorism.
The program has also been closely tied to Iranian techno-nationalist pride, symbolizing scientific progress and national independence.
History
Origins under the Shah (1950s–1970s)
Iran's nuclear ambitions 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. This led to the construction of Iran's first nuclear research facility at Tehran. In November 1967, the Tehran Research Reactor went critical – a 5 megawatt light-water reactor, which initially ran on highly enriched uranium fuel at 93% U-235, provided by the US, and was later converted in 1993 to use 20% enriched uranium with Argentine. 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 Iran's nuclear energy ambitions. In 1974 he established the Atomic Energy Organization of Iran 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 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, 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 Abdul Qadeer Khan's network were used to set up secret pilot enrichment workshops. Experiments with uranium hexafluoride gas were conducted in undeclared facilities in Tehran 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 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 aimed to design and build an arsenal of five nuclear warheads by the mid-2000s. Between 1999 and 2003, this secret program managed to acquire and improve warhead designs, 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 projects. For example, Chinese technicians conducted uranium exploration in Iran and allegedly supplied blueprints that aided Iran's construction of the Isfahan conversion facility. Iran's scientists also gained know-how from Pakistan's secret network 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, built to house thousands of centrifuges, and a heavy water production plant alongside a 40 MW heavy-water reactor 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 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, 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.