Iran admits having enough enriched uranium for 11 bombs

The current whereabouts of this stockpile remain uncertain amid ongoing U.S.-Israeli strikes starting February 28, 2026, targeting nuclear infrastructure.

By Hezy Laing

During recent nuclear talks with the U.S., Iranian negotiators reportedly boasted of possessing enough enriched uranium for making 11 nuclear bombs.

U.S. Special Envoy Steve Witkoff, shared in interviews on March 3, 2026, that the Iranians acknowledged having a stockpile of approximately 460 kilograms of uranium, enriched to 60% purity.

This claim aligns closely with prior assessments from the International Atomic Energy Agency (IAEA), which in a confidential report dated February 27, 2026, estimated Iran’s pre-strike inventory at around 440.9 kilograms of uranium enriched up to 60%.

Uranium enrichment measures the concentration of the fissile isotope uranium-235 (U-235).

Natural uranium contains about 0.7% U-235, while low-enriched uranium for civilian reactors typically reaches 3-5%.

Higher levels include 20% for research reactors and medical isotopes.

Weapons-grade uranium requires about 90% U-235 purity.

Iran’s 60% enriched material sits just short of this threshold, representing a significant technical step forward—experts note that enriching from 60% to 90% is far quicker and requires fewer centrifuge stages than earlier steps from natural to 60%.

The IAEA’s yardstick suggests roughly 42-50 kilograms of 60% enriched uranium (in uranium mass) could suffice for one bomb’s worth of weapons-grade material after further enrichment, depending on design efficiency.

Thus, 440-460 kilograms could theoretically support 9-11 devices if Iran pursued weaponization, though no evidence shows active weapon assembly.

The current whereabouts of this stockpile remain uncertain amid ongoing U.S.-Israeli strikes starting February 28, 2026, targeting nuclear infrastructure.

The IAEA report highlighted that much of the highly enriched uranium was stored in underground tunnel complexes at the Esfahan (Isfahan) Nuclear Technology Center, which appear to have survived earlier June 2025 attacks.

Satellite imagery and IAEA observations indicate regular activity at entrances to these protected sites, suggesting possible efforts to safeguard or relocate material.

Other potential locations include remnants around Natanz and Fordow, though access has been denied since mid-2025, leaving the IAEA unable to verify the stockpile’s exact size, composition, or precise location today.

This development has intensified concerns in the context of collapsed negotiations and the active conflict, with U.S. officials emphasizing Iran’s refusal to export or fully dismantle its capabilities.

Iran claims its nuclear program is “peaceful”, but the near-weapons-grade stockpile underscores the narrowed “breakout” timeline to potential bomb-grade material.