United States President Donald Trump has claimed {that a} new nuclear deal being negotiated with Iran will probably be “much better” than the 2015 Joint Complete Plan of Motion (JCPOA), which the US withdrew from in 2018 throughout his first time period.
On Tuesday, Trump prolonged the two-week ceasefire with Iran a day earlier than it was set to run out, with hopes for a second spherical of talks in Islamabad, Pakistan.
Key among the many US calls for is that Iran cease all enrichment of uranium.
Iran has at all times insisted its nuclear programme is for civilian use solely, equivalent to for energy technology, which requires uranium enrichment of between 3 p.c and 5 p.c. To construct nuclear weapons, uranium must be enriched to 90 p.c.
On this explainer, we visualise what uranium is, how it’s enriched and the way lengthy it might take Iran to make a nuclear weapon.
What’s uranium, and which nations have it?
Uranium is a dense metallic used as a gas in nuclear reactors and weapons. It’s naturally radioactive and often present in low concentrations in rocks, soil and even seawater. About 90 p.c of the world’s uranium is produced in simply 5 nations: Kazakhstan, Canada, Namibia, Australia and Uzbekistan. Reserves of uranium have additionally been present in different nations.
Uranium is extracted both by digging it out of the bottom or, extra generally, via a chemical course of that dissolves uranium from inside the rock.
Earlier than it may be used as nuclear gas, uranium is processed via a number of completely different types, together with:
- Yellowcake: Mined ore is crushed and handled with chemical substances to kind a rough powder often known as yellowcake, which, no matter its title, is often darkish inexperienced or charcoal in color, relying on how scorching it has been handled.
- Uranium tetrafluoride: Yellowcake is then handled with hydrogen fluoride gasoline, which turns it into emerald-green crystals often known as uranium tetrafluoride or inexperienced salt.
- Uranium hexafluoride: Inexperienced salt is additional fluorinated to create a stable white crystal often known as uranium hexafluoride. When heated barely, this crystal turns right into a gasoline, making it prepared for enrichment.
- Uranium dioxide: The gasoline is spun in a centrifuge machine, which chemically converts it right into a high quality, black powder.
- Gas pellets: The black powder is pressed to kind black ceramic pellets, which might then be utilized in a nuclear reactor.
How is uranium enriched?
Pure uranium exists in three types, referred to as isotopes. They’re the identical component, with the identical variety of protons however completely different numbers of neutrons.
Most naturally occurring uranium (99.3 p.c) is U-238 – the heaviest and least radioactive – whereas about 0.7 p.c is U-235 and hint quantities (0.005 p.c) are U-234.
To generate power, scientists separate the lighter, extra radioactive U-235 from the marginally heavier U-238 in a course of referred to as uranium enrichment. U-235 can maintain a nuclear chain response whereas U-238 can not.
To complement uranium, it should first be transformed right into a gasoline, often known as uranium hexafluoride (UF₆). This gasoline is fed right into a sequence of fast-spinning cylinders referred to as centrifuges. These cylinders spin at extraordinarily excessive speeds (typically greater than 1,000 revolutions per second). The spinning power pushes the heavier U-238 to the outer partitions, whereas the lighter U-235 stays within the centre and is collected.
A single centrifuge gives solely a tiny quantity of separation. To achieve larger concentrations – or “enrichment” – the method is repeated via a sequence of centrifuges, referred to as a cascade, till the specified focus of U-235 is achieved.
What are the completely different ranges of uranium enrichment?
The upper the U‑235 proportion, the extra extremely enriched the uranium is.
Small quantities (3-5 p.c) are sufficient to gas nuclear energy reactors, whereas weapons require a lot larger enrichment ranges (about 90 p.c).
The Worldwide Atomic Vitality Company (IAEA) considers something under 20 p.c to be low-enriched uranium (LEU), whereas something above 20 p.c is taken into account highly-enriched uranium (HEU).
Low enriched – lower than 20 p.c
- Industrial grade – 3-5 p.c: That is the usual gas for the overwhelming majority of the world’s nuclear energy vegetation
- Small modular reactors – 5-19.9 p.c: Utilized in extra fashionable reactors and superior analysis reactors
Extremely enriched – Greater than 20 p.c
- Analysis grade – 20-85 p.c: Utilized in specialised analysis reactors to provide medical isotopes or to check supplies
- Weapons grade – above 90 p.c: That is the extent required for many nuclear weapons
- Naval grade – 93-97 p.c: Used within the nuclear reactors that energy submarines and plane carriers
Depleted uranium, which incorporates lower than 0.3 p.c U‑235, is the leftover product after enrichment. It may be used for radiation shielding or as projectiles in armour‑piercing weapons.
How lengthy does it take to complement uranium?
The hassle it takes to complement uranium is just not linear, which means it’s rather more troublesome to go from 0.7 p.c pure uranium to twenty p.c LEU than it’s to go from 20 p.c to 90 p.c HEU. As soon as uranium reaches 60 p.c enrichment, it turns into a lot faster to succeed in 90 p.c weapons grade.
The hassle it takes to complement uranium is measured in separative work items (SWU).
Based on the IAEA, Iran is believed to have about 440kg (970lbs) of uranium enriched to 60 p.c – sufficient to theoretically construct 10 or 11 low-technology atomic bombs if refined to 90 p.c.
The then-President Mahmoud Ahmadinejad inspecting the Natanz nuclear plant in central Iran, March 2007 [Handout/Iran President’s Office via EPA]
Ted Postol, professor emeritus of science, know-how and worldwide safety on the Massachusetts Institute of Know-how (MIT), instructed Al Jazeera that earlier than the US assault on Iran’s nuclear facility at Fordow, the nation had no less than 10 cascades of 174 IR-6 centrifuges in operation – which means 1,740 IR-6 centrifuges.
The IR-6 is one among Iran’s most superior centrifuge fashions. The nation additionally has tens of hundreds of older centrifuges.
Little is understood concerning the circumstances of those centrifuges or the shares of uranium hexafluoride, that are nonetheless believed to be buried underground.
Postol has calculated that Iran’s cascade of centrifuges might produce 900 to 1,000 SWUs yearly.
“Getting from pure uranium to 60 p.c enrichment, which Iran has already achieved, takes roughly 5 years, and about 5,000 SWUs utilizing Iran’s cascades.”
“If I wish to go from 60 to 90 p.c, I solely want 500 SWUs. So, as a substitute of 5 years, [by] beginning with the 60 p.c right here, this would possibly take me 4 or 5 weeks. As a result of I’m already very enriched,” Postol stated.
Utilizing an analogy of a clock, Postol defined: “Let’s say it takes seven minutes to get 33 p.c enrichment, after which eight minutes to get to 50 p.c enrichment. It solely takes me one minute to get to whole [90 percent] enrichment.”
How simple wouldn’t it be for Iran to construct a nuclear weapon?
Postol stated Iran’s stockpile is held underground, which means a navy strike wouldn’t essentially remove the nuclear risk.
A single centrifuge cascade able to enriching weapons-grade uranium might take up “no extra ground house than a studio condominium, making it simply hidden in a small laboratory”, he stated, estimating the realm at 60sq metres (600sq ft).
“A single Prius Compact Hybrid automobile can produce sufficient electrical energy to run 4 or extra of those cascades at a time,” Postol added, which means “Iran can covertly convert its 60 p.c uranium into weapons-grade uranium metallic”.
“What they’ve achieved is put themselves ready the place anyone who thinks about attacking them with nuclear weapons has to know that they could possibly be sitting in these tunnels after such an assault, refining [and] enriching the ultimate step they should construct atomic weapons and changing it to metallic, and constructing a nuclear weapon, and that they’ve the means to ship it,” Postol stated.
“They’d have the entire technical tools they should construct the atomic weapons. They usually have the missiles, that are additionally within the tunnels and could be manufactured along with what they have already got. And the atomic weapon wouldn’t should be examined, as a result of uranium weapons don’t should be examined earlier than they’re used.”
What does the NPT say about enrichment?
The Treaty on the Non-Proliferation of Nuclear Weapons (NPT), established in 1968, is a landmark worldwide settlement aimed toward stopping the unfold of nuclear weapons and selling peaceable makes use of of nuclear power. Iran is a signatory to this pact.
The treaty helps the correct of all signatories to entry nuclear know-how and enrich uranium for peaceable functions, together with power, medical or industrial functions, with exact safeguards to make sure it’s not diverted to make weapons.
Below the NPT, nuclear-weapon states agree to not switch nuclear weapons or help non-nuclear-weapon states in growing them. Non-nuclear-weapon states additionally agree to not search or purchase nuclear weapons.
Regardless of this, most nuclear powers are at the moment modernising their arsenals fairly than dismantling them.
Many of the nations are signatories, besides 5: India, Pakistan, Israel, South Sudan and North Korea.
What agreements has Iran made about its nuclear programme up to now?
In 2015, underneath the Obama administration, Iran struck a cope with six world powers — China, France, Germany, Russia, the UK and the US — plus the European Union, often known as the JCPOA.
Below the pact, Tehran agreed to scale down its nuclear programme, capping enrichment to three.67 p.c, in alternate for aid from sanctions.
“The Iranians agreed to it, they usually have been following the treaty. There was no drawback with the treaty in any respect, completely no drawback,” Postol stated.
“They have been allowed to have 6,000 centrifuges, which, if they’d pure uranium, they might in all probability construct a bomb inside a yr in the event that they have been secretly utilizing these centrifuges, however that was all underneath inspection. They have been simply merely going to complement to three.67 p.c, which is for an influence reactor. They’re allowed to do this by the Non-Proliferation Treaty.”
However in 2018, Trump pulled out of the deal, calling it “one-sided” and reimposing sanctions on Iran. Iran responded by ultimately resuming enrichment at Fordow.
After the US killed Iran’s Common Qassem Soleimani in January 2020, Tehran said it will now not observe the set uranium enrichment limits.
Former President Joe Biden made makes an attempt to revive the deal, but it surely by no means got here to fruition attributable to disagreements over whether or not sanctions ought to be lifted first or Iran ought to rejoin the JCPOA first.
Trump has repeatedly stated Iran mustn’t have the flexibility to provide nuclear weapons. It has been one among Washington’s pink traces throughout talks with Iranian officers over the previous yr, and was additionally the central justification that Washington used when it bombed Iranian nuclear amenities through the 12-day US-Israel struggle on Iran final yr.
Within the present negotiations, Iran has stated it’s keen to “downblend” its 60 p.c enriched uranium to about 20 p.c – the edge for low-enriched uranium. The method of downblending entails mixing shares with depleted uranium to attain a decrease proportion of enriched U-235 general.
“From the perspective of exhibiting goodwill, I believe it’s good, it exhibits that the Iranians are pondering of the way to handle what the People declare are their considerations,” Postol stated.
Which nations have nuclear weapons?
9 nations possessed roughly 12,187 nuclear warheads as of early 2026, based on the Federation of American Scientists. Roughly two-thirds are owned by two nations – Russia (4,400) and the US (3,700), excluding their retired nuclear arsenals.
Some 9,745 of the full current nuclear weapons are navy stockpiles for missiles, submarines and plane. The remainder have been retired. Of the navy stockpile, 3,912 are at the moment deployed on missiles or at bomber bases, based on the Federation of American Scientists. Of those, some 2,100 are on US, Russian, British and French warheads, prepared to be used at quick discover.
Whereas Russia and the US have dismantled hundreds of warheads, a number of nations are regarded as rising their stockpiles, notably China.
The one nation to have voluntarily relinquished nuclear weapons is South Africa. In 1989, the federal government halted its nuclear weapons programme and commenced dismantling its six nuclear weapons the next yr.
Israel is believed to own nuclear weapons, with a stockpile of no less than 90. It has persistently neither confirmed nor denied this, and regardless of quite a few treaties, it faces little worldwide stress for transparency.
