Even after US strikes, Iran may still have the ability to make a nuclear bomb
US strikes could have halted Iran's ability to enrich the uranium needed to make a viable nuclear weapon. But that's not the same as preventing its ability to make a nuclear bomb.
Sunday 22 June 2025 15:08, UK
It would be sensible to wait until the dust has settled before judging whether the US strikes on Iran were, in Donald Trump's, words, "a spectacular military success".
And when dropping bombs that weigh more than 13 tonnes each, there's going to be a lot of dust.
The Pentagon says the operation against Iran's three largest nuclear facilities involved 125 military aircraft, warships and submarines, including the largest operational strike by B2 bombers in history.
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The B-2s dropped 14 of America's most powerful GBU-57 "bunker buster" bombs on the Natanz uranium enrichment plant and Iran's most sophisticated nuclear facility at Fordow.
The first time, according to the Pentagon, the weapons have been used in a military operation.
The Fordow complex, buried deep in a mountain, was the only site not previously damaged by Israeli strikes over the last few days.
The use of multiple GBU-57 bombs at Fordow is telling.
Despite their size, it was known that one of them would be insufficient to penetrate 80+ metres of solid rock believed to shelter Iran's most sophisticated uranium enrichment technology deep within Fordow.
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Satellite images reveal three visible holes at two different strike points on the mountainside above the complex.
The sites appear to be close to what may have been ventilation shafts - possibly chosen to maximise damage below and render the facility useless.
Using several of the bombs in the same location is likely designed to allow each to penetrate further than the first before detonating.
If nuclear facilities at Isfahan, Natanz and Fordow were destroyed - as the US claims - or even crippled, it would certainly halt Iran's ability to enrich the Uranium needed to make a viable nuclear weapon.
But that's not the same as preventing Iran's ability to make a nuclear bomb. To do that, they need "weapons-grade" uranium; the necessary metal-shaping, explosives and timing technology needed to trigger nuclear fission in the bomb; and a mechanism for delivering it.
The facilities targeted in the US raid are dedicated to achieving the first objective. Taking naturally occurring uranium ore, which contains around 0.7% uranium 235 - the isotope needed for nuclear fission - and concentrating it.
The centrifuges you hear about are the tools needed to enrich U-235 to the 90% purity needed for a compact "implosion"-type warhead that can be delivered by a missile.
And the reality is Iran's centrifuges have been spinning for a long time.
United Nations nuclear inspectors warned in May that Iran had at least 408kg of uranium "enriched" to 60%.
Getting to that level represents 90% of the time and effort to get to 90% U-235. And those 400kg would yield enough of that weapons-grade uranium to make nine nuclear weapons, the inspectors concluded.
The second element is something Iran has also been working on for two decades.
Precisely shaping uranium metal and making shaped explosive charges to crush it in the right way to achieve "criticality", the spark for the sub-atomic chain reaction that releases the terrifying energy in a nuclear explosion.
In its recent bombing campaign, Israel is thought to have targeted facilities where Iranian nuclear scientists were doing some of that work.
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But unlike the industrial processes needed to enrich uranium, these later steps can be carried out in laboratory-sized facilities. Easier to pack up and move, and easier to hide from prying eyes.
Given that it's understood Iran already moved enriched uranium out of Fordow ahead of the US strike, it's far from certain that Iran has, in fact, lost its ability to make a bomb.
And while the strikes may have delayed the logistics, it's possible they've emboldened a threatened Iran to intensify its warhead-making capability if it does still have one.
Making a more compact implosion-based warhead is not easy. There is debate among experts about how advanced Iran is along that road.
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But if it felt sufficiently motivated, it does have other, less sophisticated nuclear options.
Even 60% enriched uranium, of which - remember - it has a lot, can be coaxed to criticality in a much larger, cruder nuclear device.
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This wouldn't pose as much threat to its enemies, as it would be too heavy to fit on even the best of Iran's long-range missiles.
But it would, nonetheless, elevate Iran to the status of a nuclear power.