Three of Iran’s key nuclear enrichment facilities – Fordow, Natanz and Isfahan – were targeted in US airstrikes on 22 June.
The prime target of the attacks was Iran’s most advanced facility at Fordow, suspected of being used to enrich uranium close to what’s needed for a nuclear bomb.
Satellite images from the aftermath of the US strikes suggest at least six bombs were dropped there.
The secure nuclear facility, home to Iran’s main enrichment site, is buried deep under a mountain.
So exactly how much damage was done is unknown, perhaps even to Iran, which appears to have evacuated the site. The specific location of the strikes and the bombs used gives us an indication.
America used the 30,000-lb Massive Ordnance Penetrator bomb, or a GBU-57 – commonly known as a “bunker buster”.
The bunker buster is the only missile that had a chance of destroying the Fordow facility, and American planes were needed for them to be used.
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Blueprints from Iran’s Nuclear Archive, which date from before 2004 and were seized by Israeli spies in 2018, suggest the bombs targeted the tunnels under the Fordow site.
The access tunnels overground lead to a 250 metre long hall which is thought to contain the uranium enrichment centrifuges, and well as the location of what is thought to be ventilation shafts.
Iran is thought to have likely moved any enriched uranium from the facility before the strikes occurred. But if the ventilation shafts were hit, that would allow the bombs to penetrate as far as possible and hit the centrifuge hall itself.
Science and technology editor
The loss of industrial-scale centrifuge “cascades” used to enrich uranium will certainly derail any imminent deadlines in weaponisation the Islamic Republic may have set itself – more on that below.
But it has already amassed a sizeable stockpile of highly enriched uranium and may even have already enriched some of it to the 90% or so needed to make fissile material necessary for a bomb.
And despite strikes on industrial scale facilities that have taken decades to generate that stockpile, the material itself weighs less than half a tonne.
Moving it, splitting it up, concealing it, is not beyond the wit of a nation that expected these assaults may be coming.
Iran’s nuclear programme is also more than its large-scale facilities. Iran has been developing nuclear expertise and industrial processes for decades. It would take more than a concerted bombing campaign to wipe that out.
The final steps to “weaponise” highly enriched uranium are technically challenging, but Iran was known to be working on them more than 20 years ago.
Iran also does not require industrial-scale facilities like those needed to enrich uranium, meaning they could be more easily concealed in a network of smaller, discrete lab-sized buildings.
But what’s far from clear is whether Iran had actually taken steps towards weaponisation in recent years.
Recent US intelligence assessments indicated that it hadn’t. Iran’s leaders knew that very significant moves towards making a bomb would be seen as a major escalation by its neighbours and the international community.
For a long time, a key deterrent to Iran developing a nuclear weapon has been an internal political one.
It’s possible of course that position may have been shifting and these latest strikes were designed to disarm a rapidly weaponising Iran.
But it’s also possible the attacks on its nuclear programme may be forcing a previously tentative government to push harder towards making a nuclear bomb.
Fordow is only one of three nuclear facilities targeted in America’s strike, however, and one of seven that have been targeted since the conflict began.
Natanz’s uranium enrichment facility, about 140 km south of Fordow, had been subject to multiple Israeli strikes before America’s advance.
Israeli raids targeted surface buildings, including stores of enriched uranium. However, post-strike radiation monitoring suggested there was little, if any, nuclear material there.
At the weekend, Americans dropped bunker-buster bombs there too, targeting thousands of enrichment centrifuges operating in bunkers below.
Then there is the Isfahan complex. Again, Israeli missiles destroyed a number of buildings there last week. And at the weekend, US cruise missiles targeted others, including the uranium conversion plant.
At the weekend, Americans also dropped bunker-buster bombs there, targeting thousands of enrichment centrifuges operating in bunkers below.
Speaking from the White House after the attacks, Donald Trump said facilities had been “completely and totally obliterated”. But experts suggest it could take more to destroy it entirely.
“This is a very well-developed, long-standing programme with a lot of latent expertise in the country,” said Darya Dolzikova, a proliferation and nuclear security expert at RUSI, a UK defence and security thinktank
“I don’t think we’re talking about a full elimination at this point, certainly not by military means.”
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