Iran’s nuclear program is in the news again as direct negotiations began in Oman between the US and Iran. Israel has for long been concerned about Iran’ s nuclear program and constantly argues Tehran is mere months away from a final deliverable nuclear device. Whilst the US has always imposed a redline to any nuclear weapons in the Middle East the US has been hot and cold to Iran’s nuclear program. The current negotiations take place with the US-Israel alliance reconfiguring the security architecture in the Middle East and Iran’s position is central to this.
Once the darling of the west and an important Cold war ally against Communism, Iran’s nuclear ambitions were begun under the auspices of the US’s Atoms for Peace initiative. The US provided Iran with a five-megawatt research reactor at Tehran University which was somewhat ironically fuelled by weapons grade uranium.[1] The Shah of Iran envisaged an ambitions nuclear program with up to 20 reactors, despite being a signatory to the nuclear non-proliferation treaty in 1970, which subjected its nuclear activities to International Atomic Energy Agency (IAEA) inspections. But Iran was not averse to developing nuclear weapons, which was seen even by the US as key to limit Soviet expansionism into the Arabian Gulf.[2]
…Iran was not averse to developing nuclear weapons, which was seen even by the US as key to limit Soviet expansionism into the Arabian Gulf
The 1979 the Iranian revolution halted these plans, for theological and technical reasons, Ayatollah Khomeini and his immediate successor Ali Khamenei both issued Fatwa prohibiting weapons of mass destruction including chemical, biological and nuclear weapons.[3] The fatawa specifically forbade the uses and development of these weapons and was given credibility by Iran’s actions during the long Iran–Iraq war in which the Iraqi side used chemical weapons against Iran causing over 20,000 fatalities and 100,000 wounded.[4] Iran did not reciprocate despite possessing the means to do so. The fatwa contained a provision which allowed the development and use of weapons of mass destruction in circumstances where the survival of the regime necessitates their use. After the 1979 revolution most of the international nuclear cooperation with Iran was also cut off.
Diversification
The Iranian nuclear program lay dormant from the 1980’s whilst focus was shifted to more immediate concerns during the Iran-Iraq conflict. When the Iran-Iraq war ended in 1988 the priority for Iran shifted to economic development with a burgeoning population and dwindling gas and oil supplies, nuclear power was seen as a long-term solution to electricity shortages and a diversification away from fossil fuels. The Bushehr nuclear plant was seen as key to these developments and priority was given to it completion.[5]
In parallel to its overt and public nuclear activities, Iran established a clandestine nuclear program aimed at establishing its uranium enrichment capabilities. The existence of enrichment facilities in Natanz and Arak were revealed by the National Council of Resistance of Iran (NCRI), a secular resistance network in 2002, leading to heightened suspicion that Iran was developing nuclear weapons. In 2003, after the Iranian government formally acknowledged the facilities, the Atomic Energy Agency inspected them, finding that they had a more advanced nuclear program than had previously been anticipated by US intelligence.
Establishing A Nuclear Programme
Although nuclear reactors are often considered essential to a nuclear weapons program, they are actually of secondary importance. Natural uranium is composed primarily of two isotopes: uranium-238 (U-238), which makes up about 99.3%, and a much smaller portion, uranium-235 (U-235), which accounts for roughly 0.7%. At the core of any nuclear weapons program is the separation of these two isotopes—specifically, isolating the lighter, radioactive U-235 from the heavier, non-radioactive U-238. The differences in masses between these two isotopes is at an atomic level.
This separation is achieved using a cascade of high-speed centrifuges, which exploit the slight difference in mass between the isotopes. Because U-235 and U-238 are chemically identical, traditional chemical methods cannot separate them. Instead, uranium is converted into a gas, uranium hexafluoride (UF₆), and spun at extremely high speeds in centrifuges. The lighter U-235 molecules concentrate slightly toward the center, while the heavier U-238 molecules move outward. The partially enriched product from one set of centrifuges is then fed into the next stage in the cascade, gradually increasing the concentration of U-235 through multiple stages.]
As uranium enrichment progresses, the concentration of uranium-235 (U-235) increases while that of uranium-238 (U-238) decreases. For use in nuclear weapons, uranium must be enriched to weapons-grade levels—above 90% U-235. At this level, the material can sustain a chin chain reaction, leading to a nuclear detonation. The efficiency of the enrichment process is measured in Separative Work Units (SWU) per year, which represents the effort required to separate U-235 from U-238. A higher SWU capacity enables faster enrichment of larger uranium quantities to higher purity levels.
Iran’s centrifuge program has seen significant technological advancement since its inception. Initially based on designs reportedly acquired from the A.Q. Khan proliferation network in Pakistan. Iran’s early IR-1 centrifuges had a modest SWU capacity of around 0.8. Over time, Iran has developed increasingly sophisticated centrifuge models, with the IR-9 reaching up to 50 SWU. This represents a more than 60-fold increase in efficiency, substantially enhancing Iran’s ability to enrich uranium at a faster rate and to higher levels.
Iran’s centrifuge program has seen significant technological advancement since its inception. Initially based on designs reportedly acquired from the A.Q. Khan proliferation network in Pakistan.
Unlike other processes the enrichment of Uranium becomes progressively easier, it’s exponentially easier to increase enrichment from 60% to 90% than from 0.8 % to 20%. Hence the potential for rapid break out increases with high-efficiency centrifuges and higher concentrations of Uranium 235.
As of February 2025, Iran’s enriched uranium stockpile has reached approximately 8,294 kilograms, encompassing various enrichment levels and chemical forms. Iran currently possesses:
- 60% enriched Uranium: Approximately 274.8 kg in uranium mass, equating to about 406.5 kg in uranium hexafluoride (UF₆) form.
- 20% Enriched Uranium: Approximately 606.8 kg
- Up to 5% Enriched Uranium: Approximately 3,655.4 kg.
In its current state Iran can be considered a breakout state where the potential to manufacture a nuclear weapon can be measured in days and weeks rather than months and years.
Delivery System
Iran has an advanced missile programme, which has become the mainstay of nations military capabilities. As Uranium is the heaviest naturally occurring element, this would need to be miniaturised and integrated as a warhead that can be delivered with a reliable delivery system. Such integration is an immensely costly and complex process. A nuclear bomb would be useless if it could not be practically and reliably delivered with a high probability of success. For a nuclear bomb to be deployed as a ballistic missile warhead or as a cruise missile warhead a series of very significant technical hurdles must be overcome, these include nuclear physics, materials science, rocketry, missile guidance and the like.
Even if Iran achieves this, it will need to ensure it can reach supercritical mass – the amount of material needed to start a nuclear chain reaction. This is achieved by shooting one piece of sub-critical material into another or by compressing a sub-critical sphere of material using chemical explosives. This requires a nuclear test and would be the biggest giveaway Iran has mastered the process of carrying out a nuclear explosion. Whilst there are likely technical reasons Iran has not reached this stage, politics is really at the heart of this nuclear reality.
The clerical regime much like the Shah before them see Iran as a regional hegemon who has a right to its own empire. When the clerics came to power in 1979, Ayatollah Khomeini didn’t trust the armed forces, who he saw as loyal to the Shah. He established the Islamic Revolutionary Guard Corps (IRGC) who then established militia groups across the region and beyond. These unconventional forces are what allowed Iran to project power across the Middle East and South Asia. Iran’s conventional capabilities are subordinate to these unconventional forces.
Playing Atomic Roulette
When Iran’s secret sites for nuclear research and production were exposed in 2002, Iran agreed to formal talks and ever since has agreed to inspections to limit enrichment to around 30% of uranium which is well below what’s needed for nuclear weapons. In return Iran wanted sanctions removed and recognition of its regional position and being a regional power. The US throughout the 2000s agreed on some occasions on other occasions it dragged its feet and let the European powers negotiate with Iran. In 2015, the Joint Comprehensive Plan of Action (JCPOA) was agreed between the US and number of other powers with Iran. Iran gave major concessions by agreeing to the cessation of Uranium enrichment. The reduction of the 20% enriched uranium to less than 5% stock. Iran committed to not continue its activities in the reactor that produces heavy water and agreed to not produce plutonium. Iran agreed to not install new centrifuges and even agreed to unannounced inspections of its nuclear facilities.
Iran didn’t just agree to freeze its nuclear program it agreed to reverse and shrink it. Iran received sanctions relief on its oil exports, banking and financial transactions, shipping and insurance as well as access to international markets. Iran’s foreign assets were unfrozen, giving it access to $100 billion. With sanctions lifted, Iran was able to re-enter the global economy, engage in international trade and attract foreign investment. With diplomatic normalisation it opened the door for Iran to partake in regional and global issues.
Iran in 2015 agreed to abandon key parts of its nuclear program as it was getting what it desired, including the recognition it’s a regional player
Iran in 2015 agreed to abandon key parts of its nuclear program as it was getting what it desired, including the recognition it’s a regional player. When President Trump ripped up this deal in 2018, under pressure from Israel, Iran resorted back to increasing uranium enrichment and this is always a major concern for Israel, who sees Iran as an extensional threat in the region.
As Iran and the US sat down in Oman and in Rome to come to a new nuclear deal, it has once again, only been Israel that wants a regional war and strikes on Iran’s nuclear sites. After all the bellicose language from the US, there were direct negotiations between Iran and the US. A US official confirmed President Trump is prepared to make compromises to get a deal.[6]
For the moment Israel has failed to win the US to its point of view of striking Iran’s nuclear sites. With Iran on the retreat and its proxy groups decimated, Iran in reality poses little threat to Israel or to any other nation in the region. Whilst Iran recognises the regional developments are against it, it will likely bide its time for the moment. Iran’s size and influence in the region means it will always be a regional player that other nations will need to always consider and something the US has long recognised. In this context Iran’s nuclear program is a tool to keep Iran relevant and forces nations to engage her as its decades old nuclear program, despite never being tested, keeps the world powers worried about Iran, which is exactly what Iran’s aim is, with its nuclear program.
[1] U.S. Department of State, “Atoms for Peace Program,” Office of the Historian.
[2] International Atomic Energy Agency (IAEA), NPT Signatories and Treaty Text
[3] https://web.archive.org/web/20150708040618/http://farsi.khamenei.ir/treatise-content?id=228#2790
[4] https://en.wikipedia.org/wiki/Iraqi_chemical_attacks_against_Iran
[5] https://en.wikipedia.org/wiki/Bushehr_Nuclear_Power_Plant
[6] https://www.axios.com/2025/04/12/us-iran-begin-nucearl-talks-begin-oman
