Much of Iran's Near-Bomb-Grade Uranium Likely to Be in Isfahan, IAEA's Grossi Says

Why It Matters

Retaining significant highly enriched uranium keeps Iran’s nuclear breakout potential alive, heightening regional security concerns and complicating diplomatic efforts.

Key Takeaways

• IAEA estimates >200 kg 60% uranium at Isfahan
• June strikes left tunnel complex largely intact
• Iran hasn't reported HEU status post‑attacks
• 440.9 kg could yield ten nuclear weapons if fully enriched
• IAEA finds no credible evidence of coordinated weapons program

Pulse Analysis

The June 2024 airstrikes on Iran’s nuclear infrastructure marked a rare direct confrontation over proliferation risks. While the Natanz and Fordow enrichment plants suffered extensive damage, the underground tunnel complex at Isfahan emerged relatively unscathed, preserving a critical storage hub for near‑weapons‑grade uranium. This asymmetry underscores the strategic calculus of the attackers, who aimed to cripple enrichment capacity without destroying the material that could be rapidly repurposed.

According to IAEA chief Rafael Grossi, more than 200 kg of 60 % enriched uranium remains in Isfahan, a figure that represents a substantial portion of the 440.9 kg stockpile assessed before the strikes. At that enrichment level, the material sits just one step away from weapons‑grade, meaning a modest additional enrichment effort could yield enough fissile material for roughly ten nuclear warheads. Iran’s refusal to provide updated accounting or allow inspectors back into the site fuels uncertainty, leaving the international community to rely on satellite imagery and indirect intelligence to gauge any movement of the material.

The persistence of this HEU stockpile has far‑reaching implications for non‑proliferation diplomacy. It reinforces the urgency for renewed negotiations, tighter sanctions, and robust verification mechanisms to prevent a potential breakout. Moreover, the IAEA’s statement that there is no credible evidence of a coordinated weapons program does not diminish the risk posed by the existing material. Policymakers must balance deterrence with engagement, ensuring that any future diplomatic overtures address the verification gaps that currently allow Iran to retain a latent nuclear capability.