Nuclear program of Iran

The nuclear program of Iran is one of the most scrutinized nuclear programs in the world. The military capabilities of the program are possible through its mass enrichment activities in facilities such as Natanz and Arak. In June 2025, the International Atomic Energy Agency (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.

Iran's nuclear program began in the 1950s under the Pahlavi dynasty with US 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. In the 1990s, Iran pursued a full nuclear fuel cycle and acquired centrifuge technology through illicit networks, including ties with Pakistan and North Korea. 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 is currently enriching uranium to 60% purity (close to weapons-grade), and has been 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 (JCPOA) 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. According to the IAEA, Iran is "the only non-nuclear-weapon state to produce such material". 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. In October 2023, an IAEA report estimated Iran had increased its uranium stockpile 22 times over the 2015 agreed JCPOA limit. In the last months of the Biden administration, new intelligence persuaded US officials that Iran was exploring a cruder design that could enable Iran to manufacture a nuclear weapon, undeliverable by missile, in a matter of months. On 13 June 2025, Israel launched coordinated strikes across Iran, targeting nuclear facilities and damaging Natanz and other sites.

The cost of Iran's nuclear program stands on an estimate of $2-3 trillion.

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 (TRR) went critical – a 5 megawatt (thermal) light-water reactor, which initially ran on highly enriched uranium (HEU) 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 (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 (Siemens) 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 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 (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 acquire and improve warhead designs (reportedly including a re-engineered Pakistani design), 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 pledge.

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 (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.

In 2004 and 2005, the IAEA uncovered inconsistencies and omissions in Iran's disclosures, such as experiments with plutonium separation and advanced P-2 centrifuge designs that Iran had failed to report. Iran's suspension of enrichment proved short-lived as soon it resumed certain nuclear activities. In June 2004, the IAEA's Board rebuked Iran for not fully cooperating. By September 2005, the Board found Iran in non-compliance with its safeguards (a formal trigger for UN Security Council involvement). Iran reacted by ceasing voluntary implementation of the Additional Protocol and restarting enrichment work. In April 2006, President Mahmoud Ahmadinejad announced that Iran had enriched uranium to 3.5% U-235, low enriched uranium suitable for nuclear fuel, using a cascade of 164 centrifuges at Natanz. This marked Iran’s first public entry into the nuclear fuel-cycle capability club.

The international community responded firmly. In July 2006, the UN Security Council passed Resolution 1696 under Chapter VII, demanding Iran suspend all enrichment-related activities or face sanctions. When Iran defied this demand, the Security Council proceeded to adopt a series of escalating sanctions between 2006 and 2010. The first, Resolution 1737 in December 2006, imposed sanctions targeting sensitive nuclear and missile programs and banned nuclear-related trade with Iran. Further resolutions (1747 in 2007, 1803 in 2008, and 1929 in June 2010) broadened the sanctions to include arms embargos, asset freezes on key individuals and entities, and restrictions on financial dealings. These measures, backed by the U.S., Russia, China, and the EU alike, aimed to pressure Iran to halt enrichment. In parallel, the U.S. and EU introduced their own tough sanctions, including U.S. laws penalizing Iran's oil and gas investment (e.g. the Iran Sanctions Act of 1996) and European moves to restrict trade and eventually embargo Iranian oil by 2012.

Diplomatic efforts during 2005–2006 tried to resolve the standoff. The newly formed P5+1 group (China, Russia, France, the UK, the US, plus Germany) offered Iran a package of incentives in mid-2006 to halt enrichment – including nuclear fuel guarantees and economic benefits. Iran, under the hardline Ahmadinejad administration, rejected the offer, insisting on its "right" to enrich under the NPT. As talks faltered, Iran steadily expanded its enrichment work. By 2007, Iran had installed roughly 3,000 IR-1 centrifuges at Natanz and was enriching larger quantities of uranium. In 2007, a U.S. National Intelligence Estimate (NIE) assessed with high confidence that while Iran had halted its structured nuclear weapons program in 2003, it was continuing to develop technical capabilities applicable to nuclear weapons. This finding somewhat tempered the urgency of the crisis, but concerns remained over Iran's growing stockpile of enriched uranium and its long-term intentions.

A significant development came in September 2009, when Western leaders exposed yet another secret Iranian facility. U.S. President Barack Obama, joined by France's Nicolas Sarkozy and Britain's Gordon Brown, revealed intelligence on the Fordow Fuel Enrichment Plant, an underground enrichment site being built deep inside a mountain near Qom. Iran had not declared Fordow to the IAEA, violating its safeguards duty to report new facilities at the planning stage. Fordow's secret construction (begun in 2006) and fortified location heightened fears that Iran sought a secret bomb program resilient to military attack. Iran defended Fordow as a backup enrichment plant and belatedly declared it to the IAEA, but confidence in Iran's transparency was further eroded. The Fordow revelation galvanized international unity for tougher sanctions, manifested in Resolution 1929 (June 2010), which severely tightened economic restrictions on Iran.

Meanwhile, covert operations also targeted the program. The Stuxnet cyberattack, a sophisticated computer worm widely attributed to the US and Israel, was discovered in 2010 after it disrupted the control systems at Natanz, crippling a large number of Iran's spinning centrifuges. Between 2010 and 2012, four Iranian nuclear scientists were assassinated in Tehran, killings Iran blamed on Israeli and Western agents. By mid-2013, Tehran had installed over 18,000 centrifuges (mostly IR-1 models) at Natanz and Fordow, including some 1,000+ more advanced IR-2m machine. Its stockpile had grown to nearly 10,000 kg of 3.5% low-enriched uranium and about 370 kg of 20% medium-enriched uranium – the latter quantity almost enough, if further enriched to weapons-grade, for one nuclear bomb. The world's concern was that Iran's "breakout" time, i.e. the time to produce bomb-grade uranium for a weapon, had shrunk to a matter of a few months.

Diplomatic efforts and the JCPOA (2013–2018)

In 2013, Iran's newly elected president, Hassan Rouhani, a centrist cleric and former nuclear negotiator, campaigned on ending sanctions through diplomacy. He had cautious backing from Supreme Leader Ali Khamenei. Meanwhile, US President Barack Obama, having already authorized secret backchannel talks with Iranian officials in Oman in 2012, was open to a diplomatic solution. Formal multilateral negotiations resumed in October 2013 between Iran and the P5+1. By November 24, they reached the Joint Plan of Action (JPOA), an interim agreement that froze key elements of Iran's nuclear program in exchange for limited sanctions relief. Iran halted enrichment above 5% U-235, neutralized its 20% stockpile through dilution or conversion, suspended centrifuge installation, and agreed not to fuel or operate the Arak heavy-water reactor. In return, it received access to about $4.2 billion in frozen assets and limited relief on petrochemical and precious metals trade. The JPOA, which began in January 2014, was extended several times while talks continued toward a final accord.

After 20 months, the parties reached the Joint Comprehensive Plan of Action (JCPOA) on July 14, 2015. Under this framework Iran agreed tentatively to accept restrictions on its nuclear program, all of which would last for at least a decade and some longer, and to submit to an increased intensity of international inspections. The Joint Comprehensive Plan of Action (JCPOA), was finally reached on 14 July 2015. The final agreement is based upon "the rules-based nonproliferation regime created by the Nuclear Non-Proliferation Treaty (NPT) and including especially the IAEA safeguards system".

Enrichment was capped at 3.67% for 15 years, and the enriched uranium stockpile limited to 300 kg. Only 5,060 first-generation IR-1 centrifuges could operate at Natanz, and Fordow was repurposed for non-enrichment research. The Arak IR-40 reactor was to be redesigned and rebuilt, with its original core removed and filled with concrete to eliminate plutonium production capability. Iran agreed to provisionally implement the IAEA Additional Protocol, and accepted enhanced verification, including continuous surveillance of enrichment and conversion facilities, monitoring of uranium mines and mills, and oversight of centrifuge manufacturing. Iran's excess enriched uranium, including the bulk of its 20% material, was to be shipped abroad or down-blended. Over 13,000 centrifuges were dismantled. Limited R&D on advanced centrifuges was allowed under controlled conditions without accumulating enriched uranium.

In exchange, the UN, US, and EU committed to stepwise sanctions relief: UN Security Council Resolution 2231 endorsed the JCPOA. It retained a conventional arms embargo for five years and ballistic missile restrictions for eight, and introduced a "snapback" mechanism allowing reimposition of sanctions in case of noncompliance. US and EU sanctions targeting Iran’s energy, finance, shipping, and trade sectors were suspended. On "Implementation Day" (January 16, 2016), the IAEA verified Iranian compliance, leading to the unfreezing of billions in Iranian assets and restoration of access to international banking (e.g., SWIFT). Some US sanctions tied to terrorism and human rights remained in force.

US Withdrawal and Iranian violations (2018–2025)

In 2018, the Mossad reportedly stole nuclear secrets (a cache of documents from Iran's weaponization program) from a secure warehouse in the Turquzabad district of Tehran. According to reports, the agents came in a truck semitrailer at midnight, cut into dozens of safes with "high intensity torches", and carted out "50,000 pages and 163 compact discs of memos, videos and plans" before leaving in time to make their escape when the guards came for the morning shift at 7 am. According to a US intelligence official, an "enormous" Iranian "dragnet operation" was unsuccessful in recovering the documents, which escaped through Azerbaijan. According to the Israelis, the documents and files, which it shared with European countries and the United States, demonstrated that the AMAD Project aimed to develop nuclear weapons, that Iran had a nuclear program when it claimed to have "largely suspended it", and that there were two nuclear sites in Iran that had been hidden from inspectors. Iran claims "the whole thing was a hoax". This influenced Trump's decision to withdraw the United States from the JCPOA and reimpose sanctions on Iran.

In 2018, the United States withdrew from JCPOA, with President Donald Trump stating that "the heart of the Iran deal was a giant fiction: that a murderous regime desired only a peaceful nuclear energy program". The US also contended that the agreement was inadequate because it did not impose limitations on Iran's ballistic missile program, and failed to curb its backing of proxy groups.

In February 2019, the IAEA certified that Iran was still abiding by the international Joint Comprehensive Plan of Action (JCPOA) of 2015. However, on 8 May 2019, Iran announced it would suspend implementation of some parts of the JCPOA, threatening further action in 60 days unless it received protection from US sanctions. In July 2019, the IAEA confirmed that Iran has breached both the 300 kg enriched uranium stockpile limit and the 3.67% refinement limit. On 5 November 2019, Iranian nuclear chief Ali Akbar Salehi announced that Iran will enrich uranium to 5% at the Fordow Fuel Enrichment Plant, adding the country had the capability to enrich uranium to 20% if needed. Also in November, Behrouz Kamalvandi, spokesman for the Atomic Energy Organization of Iran, stated that Iran can enrich up to 60% if needed. President Hassan Rouhani declared that Iran's nuclear program would be "limitless" while the country launches the third phase of quitting from the 2015 nuclear deal.

On January 3, 2020, the U.S. assassinated Iranian Quds Force commander Qasem Soleimani, and Iran responded with missile strikes on US. bases. Two days later, Iran's government declared it would no longer observe any JCPOA limits on uranium enrichment capacity, levels, or stockpile size. In March 2020, the IAEA said that Iran had nearly tripled its stockpile of enriched uranium since early November 2019. In late June and early July 2020, there were several explosions in Iran, including one that damaged the Natanz enrichment plant (see 2020 Iran explosions). In September 2020, the IAEA reported that Iran had accumulated ten times as much enriched uranium as permitted by the JCPOA. On 27 November 2020, Iran's top nuclear scientist, Mohsen Fakhrizadeh, was assassinated in Tehran. Fakhrizadeh was believed to be the primary force behind Iran's covert nuclear program for many decades. The New York Times reported that Israel's Mossad was behind the attack and that Mick Mulroy, the former Deputy Defense Secretary for the Middle East said the death of Fakhirizadeh was "a setback to Iran’s nuclear program and he was also a senior officer in the Islamic Revolutionary Guard Corps, and that "will magnify Iran’s desire to respond by force."

Throughout 2021 and 2022, Iran installed cascades of advanced centrifuges (IR-2m, IR-4, IR-6) at Natanz and Fordow, significantly increasing its enrichment output. In February 2021, the IAEA reported that Iran stopped allowing access to data from nuclear sites, as well as plans for future sites. In April 2021, a sabotage attack struck the Natanz enrichment plant, causing an electrical blackout and damaging centrifuges. Iran responded by further upping enrichment: days later, it began producing 60% enriched uranium, an unprecedented level for Iran, just short of weapons-grade (90% and above). This 60% enrichment took place at Natanz, and later at Fordow as well, yielding a stockpile that as of early 2023 exceeded ~70 kg of 60% uranium. If Iran chose to enrich this material to 90%, it would be sufficient for several nuclear warheads. The UK, France, and Germany said that Iran has "no credible civilian use for uranium metal" and called the news "deeply concerning" because of its "potentially grave military implications" (as the use of metallic enriched uranium is for bombs). On 25 June 2022, in a meeting with the senior diplomat of the EU, Ali Shamkhani, Iran's top security officer, declared that Iran would continue to advance its nuclear program until the West modifies its "illegal behavior."

In July 2022, according to an IAEA report seen by Reuters, Iran had increased its uranium enrichment through the use of sophisticated equipment at its underground Fordow plant in a configuration that can more quickly vary between enrichment levels. In September 2022, Germany, United Kingdom and France expressed doubts over Iran's sincerity in returning to the JCPOA after Tehran insisted that the IAEA close its probes into uranium traces at three undeclared Iranian sites. The IAEA said it could not guarantee the peaceful nature of Iran's nuclear program, stating there had been "no progress in resolving questions about the past presence of nuclear material at undeclared sites." United Nations Secretary-General António Guterres urged Iran to hold "serious dialogue" about nuclear inspections and said IAEA's independence is "essential" in response to Iranian demands to end probes. In February 2023, the IAEA reported having found uranium in Iran enriched to 84%. The Iranian government has claimed that this is an "unintended fluctuation" in the enrichment levels, though the Iranians have been openly enriching uranium to 60% purity, a breach of the 2015 nuclear deal. In 2024, Iranian President Masoud Pezeshkian expressed interest in reopening discussions with the United States on the nuclear deal.

In late October 2024, during a series of Israeli airstrikes in Iran carried out in response to a ballistic missile attack earlier that month, Israel reportedly destroyed a top-secret nuclear weapons research facility known as the Taleghan 2 building, located within the Parchin military complex. In November 2024, Iran announced that it would make new advanced centrifuges after IAEA condemned Iranians' non-compliance and secrecy.

Current status and recent escalations (2025–)

In January 2025, it was reported that Iran is developing long-range missile technology under the Islamic Revolutionary Guard Corps (IRGC), with some designs based on North Korean models. According to the National Council of Resistance of Iran (NCRI), these missiles, such as the Ghaem-100 and Simorgh, could carry nuclear warheads and reach targets as far as 3,000 km away, including parts of Europe.  

In March 2025, U.S. President Donald Trump sent a letter to Iran seeking to reopen negotiations. Ayatollah Ali Khamenei later said, "Some bullying governments insist on negotiations not to resolve issues but to impose their own expectations," which was seen as in response to the letter.

In April 2025, Trump revealed that Iran had decided to undertake talks with the United States for an agreement over its nuclear program. On 12 April, both countries held their first high-level meeting in Oman, followed by a second meeting on 19 April in Italy. On May 16, Trump sent Iran an offer and said they have to move quickly or else bad things would happen. On May 17, Khamenei condemned Trump, saying that he lied about wanting peace and that he was not worth responding to, calling the US demands "outrageous nonsense." Khamenei also reiterated that Israel is "cancerous tumour" that must be uprooted.

On May 31, 2025, IAEA reported that Iran had sharply increased its stockpile of uranium enriched to 60% purity, just below weapons-grade, reaching over 408 kilograms, a nearly 50% rise since February. The agency warned that this amount is enough for multiple nuclear weapons if further enriched. It also noted that Iran remains the only non-nuclear-weapon state to produce such material, calling the situation a "serious concern." In June 2025, the NCRI said Iran is pursuing nuclear weapons through a new program called the "Kavir Plan". According to the NCRI, the new project involves six sites in Semnan province working on warheads and related technology, succeeding the previous AMAD Project.

On June 10, Trump stated in that Iran was becoming "much more aggressive" in the negotiations. On 11 June, the Iranian regime threatened US bases in the Middle East, with Defense Minister Aziz Nasirzadeh stating, "If a conflict is imposed on us... all US bases are within our reach, and we will boldly target them in host countries." The U.S. embassy in Iraq evacuated all personnel. The Iran-backed Yemen-based Houthi movement threatened to attack the United States if a strike on Iran were to occur. CENTCOM presented a wide range of military options for an attack on Iran. UK issued threat advisory for ships on Arabian Gulf. U.S. Secretary of Defense Pete Hegseth told Congress that Iran was attempting a nuclear breakout.

On 12 June 2025, IAEA found Iran non-compliant with its nuclear obligations for the first time in 20 years. Iran retaliated by announcing it would launch a new enrichment site and install advanced centrifuges. On the night of June 13, Israel has initiated Operation Rising Lion, a large‑scale aerial assault targeting Iranian nuclear facilities, missile factories, military sites, and commanders across cities including Tehran and Natanz.

Main facilities

Natanz

Natanz, located about 220 km southeast of Tehran, is Iran's main uranium enrichment site. The facility includes an underground Fuel Enrichment Plant (FEP) housing large cascades of gas centrifuges, as well as a smaller Pilot Fuel Enrichment Plant (PFEP) above the ground. Iran has installed thousands of first-generation ''IR-1'' centrifuges and more advanced models (''IR-2m, IR-4, IR-6'') here. As of 2025, Natanz is enriching uranium up to 60% U-235, a level approaching weapons-grade. Iran has also begun excavating a new enrichment hall deep under the adjacent ''Kūh-e Kolang Gaz Lā'' (“Pickaxe Mountain”) to harden the site against airstrikes.

In the past, the site saw multiple sabotage attacks (such as the Stuxnet cyberattack and unexplained explosions). On 13 June 2025, the site was struck by Israeli airstrikes during Operation Rising Lion.

Fordow

Fordow (near the city of Qom, approximately 100 km southwest of Tehran) is an underground enrichment site built inside a mountain. Originally designed to host about 3,000 centrifuges, Fordow was revealed in 2009 and appears engineered to withstand airstrikes. It was re-purposed under the 2015 nuclear deal as a research facility with no enrichment, but Iran resumed enrichment at Fordow after 2019. By 2025, Iran is using Fordow to enrich uranium up to 60% U-235 as well, deploying advanced IR-6 centrifuges. Fordow's smaller size and heavy fortification make it a particular proliferation concern. The IAEA still inspects Fordow, but Iran's suspension of the Additional Protocol means inspectors no longer have daily access. In June 2025, Iran revealed plans to install advanced centrifuges at the facility.

Bushehr

Bushehr is Iran's only commercial nuclear power station, situated on the Persian Gulf coast in southern Iran. The site's first unit, a 1000 MWe pressurized water reactor (VVER-1000) built with Russian assistance, began operation in 2011–2013. Russia supplies the enriched fuel for Bushehr-1 and removes the spent fuel, an arrangement that minimizes proliferation risk. Iran is constructing two additional VVER-1000 reactors at Bushehr with Russian collaboration, slated to come online in the late 2020s. Bushehr is under full IAEA safeguards. Its operation is closely monitored by the Agency, and Iran, like any NPT party, must report and permit inspection of the reactor and its fuel.

Arak

Arak, about 250 km southwest of Tehran, is the site of Iran's IR-40 heavy water reactor and associated heavy water production plant. The 40 MW (thermal) reactor, still under construction, is designed to use natural uranium fuel and heavy water moderation, which would produce plutonium as a byproduct in the spent fuel. In its original configuration, the Arak reactor could have yielded enough plutonium for roughly 1–2 nuclear weapons per year if Iran built a reprocessing facility (which it does not have). Under the JCPOA, Iran agreed to halt work on Arak and redesign the reactor to a smaller, proliferation-resistant version. In January 2016, Iran removed and filled Arak’s original reactor core with concrete, disabling it. As of mid-2025, Iran, with international input, has been modifying the reactor design to limit its plutonium output, and the reactor has not yet become operational. A heavy water production plant at the Arak site continues to operate (25 tons/year capacity), supplying heavy water for the reactor and medical research; Iran's heavy water stockpile is under IAEA monitoring per its safeguards commitments.

Isfahan Nuclear Technology Center

Isfahan, located ~350 km south of Tehran, is another major hub of Iran's nuclear fuel cycle and research activities. The site hosts the Uranium Conversion Facility (UCF) where yellowcake (uranium ore concentrate) is converted into uranium hexafluoride (UF₆) gas – the feedstock for enrichment. The UCF at Isfahan has produced hundreds of tons of UF₆ for Natanz and Fordow. Isfahan also houses a Fuel Fabrication Plant for producing nuclear fuel (e.g. fuel plates for the Tehran Research Reactor and prototype fuel for Arak). In addition, the Isfahan Nuclear Technology Center includes laboratories and several small research reactors, supplied by China, used for research and isotope production.

Tehran Research Reactor (TRR)

Located in Tehran at the headquarters of the Atomic Energy Organization of Iran, the Tehran Research Reactor is a 5 MW pool-type research reactor. It was provided by the United States in 1967 as part of the "Atoms for Peace" program. Originally fueled with highly enriched uranium (HEU), the TRR was converted in 1987 to use 19.75% enriched uranium (LEU). The TRR is used to produce medical isotopes (such as molybdenum-99) and for scientific research. Its need for 20% LEU fuel became a point of contention when Iran's external fuel supply ran low in 2009, prompting the decision to enrich uranium to 20%.

Other sites

According to a May 2025 report by IAEA, several undeclared locations in Iran remain at the center of its investigation into Iran's past nuclear activities. These include Turquzabad, first identified publicly in 2018 when Israeli Prime Minister Benjamin Netanyahu claimed it was a secret nuclear warehouse. Inspectors later detected man-made uranium particles there in 2019. Two other sites, Varamin and Marivan, also yielded traces of undeclared nuclear material when IAEA inspectors were granted access in 2020. A fourth site, Lavisan-Shian, has been under scrutiny as well, though inspectors were never able to visit it because it was demolished after 2003. IAEA concluded that these locations, and possibly others too, were part of an undeclared nuclear program conducted by Iran up until the early 2000s.

On 12 June 2025, Iran announced the activation of a third uranium enrichment site following the IAEA's first formal censure of Iran in two decades. While the location has not been disclosed, Iranian officials described it as "secure and invulnerable."

Views on Iran's nuclear power program

Analysts and researchers say that a nuclear-armed Iran poses significant global security risks and undermines the stability of the Middle East. International Atomic Energy Agency (IAEA) chief Rafael Grossi warns that an Iranian nuclear weapon could trigger broad nuclear proliferation, as other countries, particularly in the Middle East, may seek similar capabilities in response. Concerns also exist that Iran's nuclear assets could fall into the hands of extremist factions due to internal instability or regime change. Additionally, the prospect of Iran acquiring nuclear weapons has raised concerns about a regional arms race, with countries such as Saudi Arabia and Turkey indicating they might pursue nuclear capabilities if Iran were to develop them. The potential transfer of nuclear technology or weapons to radical states and terrorist organizations heightens fears of nuclear terrorism.

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 cost of Iran's nuclear program

Direct financial expenditures

Estimating the direct costs of Iran's nuclear program is complicated by secrecy, but available assessments suggest significant expenditures.

The Bushehr plant alone has generated only $5 billion worth of electricity over ten years, a net loss compared to its construction cost. The enrichment program also underperforms globally, producing what Urenco accomplishments in five hours.

Indirect economic burdens and opportunity costs

sanctions and lost economic opportunities far outweigh direct spending:

Despite vast reserves of natural gas and abundant solar potential, Iran continues to invest in high-cost nuclear projects. Former Foreign Minister Zarif admitted that nuclear expenditures could have upgraded the entire energy sector over 20 times.

See also

* Iran and state-sponsored terrorism
* Iran and weapons of mass destruction
* Iran's ballistic missiles program
* Timeline of the nuclear program of Iran
* June 2025 Israeli strikes on Iran

Malware:
* Duqu
* Flame (malware)
* Stuxnet

People
* Akbar Etemad, the "father of Iran's nuclear program"
* Mehdi Sarram, nuclear scientist
* List of Iranian nuclear negotiators

References

External links

The first-ever English-language website about Iran's nuclear energy program

Iran's Atomic Energy Organization

In Focus: IAEA and Iran
IAEA

Iran's Nuclear Program
collected news and commentary at ''The New York Times''

Iran Nuclear Resources
parstimes.com

Annotated bibliography for the Iranian nuclear weapons program from the Alsos Digital Library for Nuclear Issues

{{Iran–Israel proxy conflict
Nuclear program of Iran
Iran–European Union relations
Iran–Israel proxy conflict
Iran–United States relations
Nuclear energy in Iran
Politics of Iran
Underground construction