The US-Iran memorandum commits Iran to "destroy the enriched stockpile", down-blended on site under International Atomic Energy Agency (IAEA) supervision, by a mechanism "to be mutually agreed" with no inspector-return date set1. The IAEA is the United Nations nuclear watchdog whose seals are the only independent check on what Iran holds. In the same 18 June message endorsing the deal, Mojtaba Khamenei branded full IAEA access and any transfer of the stockpile "excessive demands"2.
The inspectors had been locked out for 97 days, so the agency could not confirm the seals it left behind in February were even intact. The 440.9 kg of 60 per cent enriched uranium sat unverified, "likely still at Isfahan" on satellite imagery alone, by Director General Rafael Grossi's own account3. Sixty per cent enrichment is a short technical step from the 90 per cent used in a weapon, which is why the stockpile, not the centrifuges, is the object everyone is counting.
Vice President JD Vance had promised the agency's return under the MOU but named no date and could not locate the material; Grossi had warned that any movement of it must be formally declared. The deal defers the nuclear question by 60 days into a phase whose red lines are already drawn against it. If full access is the US minimum for the next round, Khamenei has pre-classified that minimum as unacceptable before the talks resume.
