US Israel Iran conflict: What is Fordow, the underground nuclear site that only a US bomb can destroy

US Israel Iran conflict: As the conflict between Iran and Israel enters its eighth day, all eyes are on the Islamic Republic’s underground uranium enrichment site in Fordow — which houses its most advanced centrifuges — and on whether the United States will intervene directly to destroy it.With about 2,000 operational centrifuges, the enrichment facility produces uranium enriched to 60 per cent — a step away from weapons-grade 90 per cent enrichment.
What sets this site apart–located roughly 95 km southwest of the capital, Tehran–from the other facilities damaged in Israel’s barrage on June 13 is its depth: built into the side of a mountain and buried approximately 260 to 300 feet underground, it is effectively impervious to air strikes. Several sites sustained major damage in the Israeli barrage on June 12 and the following days; however, Fordow remains intact.
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Experts suggest that while conventional air strikes can damage the surface of the facility, rendering it temporarily inoperable, destroying the cascades of centrifuges and the uranium stockpile housed within would require the direct involvement of the US, which possesses the warhead to destroy it – the GBU-57 A/B Massive Ordnance Penetrator, a 30,000-pound ‘bunker buster’ designed to penetrate up to 200 feet of earth or reinforced concrete before detonation.
The GBU-57 A/B Massive Ordnance Penetrator is a “bunker buster” weighing 30,000 pounds that is capable of penetrating 200 feet of earth or concrete before detonating. (AP Photo)
Moreover, the US possesses the delivery platform capable of deploying the round – the B-2 Spirit stealth bomber.
What is Fordow
Construction at the Fordow Fuel Enrichment Plant began in the second half of 2007, according to Tehran, and it became operational in 2009 — the same year Western intelligence disclosed the site’s presence to the International Atomic Energy Agency (IAEA), leading Iran to publicly acknowledge it.
In 2009, intelligence agencies revealed that Iran was trying to install 3,000 centrifuges at the facility, according to media reports.Story continues below this ad
Two years later, then-IAEA Director General Yukiya Amano reported that Iran had “installed centrifuges in Fordow with the stated objective” of producing uranium enriched up to 20 per cent. The next year, the nuclear watchdog reported that Iran had tripled the monthly production of 20 per cent-enriched uranium in Fordow.
UN inspections in 2012 revealed the presence of tunnels with thick walls and blast-proof doors, with some bunkers protected 300 feet of rock, according to a Washington Post report.
Iran agreed to suspend enrichment at Fordow and repurpose the site into a research facility once the Joint Comprehensive Plan of Action (JCPOA) was signed in 2015 during the Obama adminration.

However, following the fallout between Tehran and Washington in 2018, owing to the Trump adminration withdrawing the US from the agreement and slapping sanctions on Tehran over its ballic missile programme, uranium enrichment activities resumed at the site. Tehran has maintained that the programme is intended for peaceful purposes.Story continues below this ad
During an unannounced IAEA survey in 2023, inspectors found particles of uranium purified to 83.7 per cent, making it near weapons-grade. The nuclear watchdog also said that Iran had connected two sets of centrifuges that allowed it to purify uranium to 60 per cent.
A Reuters report said that 166.6 kg of uranium enriched to up to 60 per cent was produced in the most recent quarter, which, if enriched further, could be used to produce about four nuclear weapons, according to an IAEA yardstick. However, the UN nuclear watchdog’s Director General, Rafael Grossi, told Sky News on Thursday that they could not affirm that Iran is building a nuclear weapon. On the same day, Israel hit the Khondab Heavy Water Research Reactor, which was under construction.

After the IAEA Board of Governors declared that Iran breached the provisions of its nuclear safeguards agreement in a vote, Tehran said that it will pursue its programme and build another facility with more advanced centrifuges. The IAEA also published a report stating that Iran conducted “secret nuclear activities” at three locations – in direct contravention of the provisions of the JCPOA, which could invite sanctions from European stakeholders of the agreement.

Hours after the IAEA’s announcement, Israel, which has been sceptical of Tehran’s nuclear ambitions, launched “pre-emptive” strikes against its nuclear and military infrastructure last week under the umbrella of Operation Rising Lion, targeting facilities and killing key figures of its military and nuclear programme.Story continues below this ad
Natanz, the regime’s main enrichment site with over 13,500 operational centrifuges, was also hit, Reuters reported. The facility’s Pilot Fuel Enrichment Plant (PFEP) houses 164 advanced centrifuges that can enrich uranium to up to 60 per cent.
Since then, the two countries have traded missiles and drones. Israel has struck key nuclear facilities in Natanz, Isfahan, Arak and Tehran; Iranian oil and gas facilities, including those in the capital, Tehran, and South Pars. It has also dealt damage to the Islamic regime’s surface-to-surface launchers and airports. Iran, on the other hand, hit the Soroka hospital complex in southern Israel and the Weizmann Institute of Science.
The death toll in Iran has crossed 220, according to a report the BBC, while 24 have been killed in Israel.
Will US join Israel’s war
As of Friday (June 20), the Fordow nuclear facility stands unscathed, becoming the sole determinant of US involvement. According to an Al Jazeera report, the site is protected Iranian and Russian surface-to-air missile systems, though some of those defences may have been hit in recent Israeli strikes, clearing the way for the B-2. If the US abstains from attacking, Israeli ground forces may get involved, protracting the conflict.Story continues below this ad
According to an ABC News report, the B-2 bomber fleet is stationed at Whiteman Air Force Base in Missouri and would need about 15 hours to reach Iran if deployed.
Last year, Israel killed Hassan Nasrallah, the chief of the Iranian proxy Hezbollah, in an air strike using the BLU-109 bunker-buster bomb. However, the warhead can only penetrate up to 2.4 metres (almost 8 feet), according to a report The Guardian. Israel also owns the GBU-28 — the variant which was used to punch through Iraqi bunkers in Operation Desert Storm in 1991 — but it can penetrate up to a depth of 20 feet.
The Wall Street Journal reported that the US has approved plans to attack Iran but withheld the final order to see if Tehran would abandon its nuclear programme. This mirrors the public stand of the US adminration, with US President Donald Trump saying he will decide within two weeks whether to authorise a direct US military strike on Iran.
On the other hand, news agency Reuters quoted a senior Iranian official saying that zero enrichment will be rejected, especially after Israeli strikes. He added that the role of European powers is now more prominent, as Tehran is unwilling to engage with Washington amid Israel’s campaign.Story continues below this ad
Earlier, Trump, who has been vocal about his support for Israel’s campaign against Tehran’s nuclear programme, said: “Iran cannot have a nuclear weapon. It’s very simple — you don’t have to go too deep into it. They just can’t have a nuclear weapon.”
He demanded Iran’s unconditional surrender, drawing a sharp response from the Islamic Republic’s Supreme Leader Ayatollah Ali Khamenei, who said that “any US strike will have serious, irreparable consequences” and that Iran “will not surrender.”