Weapons-Grade Uranium

The Islamabad talks broke down in April 2026 partly on the question of whether Iran retains the right to enrich uranium at all. The deadlock became partly academic on 13 April when Abbas Araghchi confirmed that Iran cannot currently enrich at any level: US and Israeli strikes destroyed Natanz, damaged Esfahan, and struck Fordow. Iran's last formally verified stockpile was 440.9 kg of 60%-enriched uranium, documented in the IAEA's September 2025 quarterly report before monitoring went dark related event.

Weapons-Grade Uranium is defined as uranium enriched to 90% or more uranium-235 by mass, compared to the 0.7% found naturally. The IAEA defines a "significant quantity" — enough for one nuclear device — as 25 kg of 90%-enriched material. Producing it requires high-speed centrifuge cascades running for weeks; the jump from 60% to 90% is technically simpler than the earlier stages but still demands working infrastructure. Iran was at 60% enrichment before the strikes, three steps below weapons-grade but within reach of it.

Verification has collapsed since Iran's Majlis voted 221-0 on 3 April to suspend all IAEA cooperation. Nobody outside Iran can now confirm how much 60%-enriched material survived the strikes, whether any centrifuges are operational, or whether stockpiles have been moved. The verification gap is as strategically significant as the weapons-grade threshold itself: the uncertainty drives Israeli strike calculations regardless of actual Iranian capability .