Iran Increased Stockpile of Near Weapons-Grade Uranium, UN Watchdog Reports

3 September, 2025

The International Atomic Energy Agency (IAEA) reported that Iran increased its stockpile of uranium enriched to 60% purity—a short technical step from weapons-grade—just before an Israeli military attack in June. According to a confidential report, Iran's stockpile of this highly enriched uranium grew by over 32 kg to 440.9 kg. The UN nuclear watchdog also expressed "serious concern" that its inspectors have been unable to verify Iran's stockpile for over two and a half months following the conflict.

Unpacked:

What is the significance of uranium being enriched to 60% purity?

Uranium enriched to 60% purity is considered highly enriched and is close to weapons-grade (about 90% purity). This makes it technically easier for Iran to rapidly produce material suitable for a nuclear weapon, should it choose to do so. Typically, civilian nuclear reactors use uranium enriched to only about 3-5%.

Why has the IAEA been unable to verify Iran's uranium stockpile recently?

The IAEA has been unable to verify Iran’s stockpile because Iran has restricted inspector access following recent regional conflict and the attack in June. Political tensions and security concerns have repeatedly led Iran to limit or deny the UN watchdog’s monitoring activities in the past.

How close is Iran to having enough material for a nuclear weapon?

Experts estimate that if Iran enriched its entire stockpile to weapons-grade (about 90%), it could produce enough material for at least two nuclear bombs. The 'breakout time'—the time needed to produce enough weapons-grade uranium for one bomb—has been reduced to roughly three months due to the size and enrichment level of Iran's current stockpile.

What recent events led to increased tensions around Iran's nuclear program?

Tensions rose after Iran's uranium enrichment increased and following an Israeli military attack in June. The attack, along with Iran’s decision to limit IAEA inspections, has fueled international concerns about Iran’s intentions and the potential for nuclear proliferation in the region.