Iranian Foreign Ministry spokesman Esmail Baghaei denied Trump’s claim, saying on state-run TV April 17 that “Iran’s enriched uranium is not going to be transferred anywhere under any circumstances.” Araghchi had previously stated that the stockpile must remain in Iran, but said Iran would blend down the highly enriched uranium gas to lower levels.
On several occasions, Trump has threatened to deploy US forces to remove the enriched uranium from Iran, an operation that would likely require thousands of troops on the ground, take several weeks, and require the transport of special equipment to secure the material.
It is also unclear if the United States could locate all of the enriched uranium, some of which may be difficult to access given US strikes on key nuclear facilities in June. The two sides also disagreed over the duration of a suspension on certain nuclear activities, particularly enrichment.
The HEU problem is the most specific, physical, and tangible obstacle in the entire Iran war’s diplomatic track. It is not a language problem. It is not a sequencing problem. It is a 400-kilogram material problem: there exists, in Iran, approximately 400kg of uranium enriched to 60% purity — enough for 11 nuclear weapons after further processing — and the US wants it out of Iran, and Iran has said it is “not going to be transferred anywhere under any circumstances.”
Why Iran Won’t Transfer the HEU
Iran’s refusal to transfer its enriched uranium has three distinct layers that are often conflated but need to be separated to understand the obstacle.
Legal layer: Iran maintains that its enriched uranium, produced under its NPT rights and IAEA-monitored enrichment programme, is sovereign Iranian material. Transferring it to the United States — or to any third party at US request — would constitute an internationally coerced transfer of sovereign state material under military pressure, a precedent that no NPT signatory could accept without undermining the legal integrity of national sovereign control over civilian nuclear assets.
Security layer: Iran’s enriched uranium stockpile is, in the IRGC’s strategic assessment, a deterrent asset. It doesn’t provide Iran with nuclear weapons — enrichment to 90%+ and weapons design would still be required. But it provides Iran with a nuclear weapons latency: the capacity to potentially produce weapons-grade material in a shorter time than if starting from zero. Removing that latency entirely, at US demand, makes Iran more vulnerable to future US-Israeli strikes by eliminating the deterrent value of potential weaponisation capability.
Political layer: The HEU stockpile has become a symbol of Iranian national resistance in domestic political discourse — particularly for the IRGC. Surrendering it is associated with capitulation in a way that agreeing to a 20-year enrichment moratorium is not. Iran can tell its domestic audience it has not surrendered the enrichment right if it accepts a moratorium. It cannot tell that audience it has not surrendered its HEU if the material is physically removed.
What Iran Said It Would Do Instead
Araghchi had previously stated that the stockpile must remain in Iran, but said Iran would blend down the highly enriched uranium gas to lower levels.
“Blend down” — this is Iran’s proposed alternative to transfer. Blending down means mixing Iran’s 60%-enriched uranium with natural or lower-enriched uranium to produce a less concentrated material — 20% or below — that retains the bulk of the uranium mass but is much further from weapons-grade. Iran can say it did not remove its material; the US can say the weapons-grade risk has been reduced.
The blending-down proposal is not the same as the US demand for transfer, but it addresses the core proliferation concern: preventing the rapid conversion of the HEU stockpile to weapons-grade material. A monitoring regime that confirms blending-down has been completed, with IAEA verification that the resulting material is no longer close to weapons-grade, could satisfy the verification requirement even if it does not satisfy the maximalist position of complete removal.
The Covert Removal Option — Why It Wasn’t Used
On several occasions, Trump has threatened to deploy US forces to remove the enriched uranium from Iran, an operation that would likely require thousands of troops on the ground, take several weeks, and require the transport of special equipment to secure the material. It is also unclear if the United States could locate all of the enriched uranium, some of which may be difficult to access given US strikes on key nuclear facilities in June.
Trump threatened a military removal operation for the HEU. The Arms Control Association’s assessment of that operation explains why it hasn’t been attempted: thousands of troops, weeks of operation, special equipment, and uncertain location data. A military HEU removal operation would require US ground forces operating inside Iran in a contested environment — a far more ambitious military operation than any air campaign.
It would require securing and transporting fissile material under hostile conditions with a chain of custody that could not be guaranteed. And it would require locating all the material — including any dispersed to secondary sites after the bombing campaign, which Iran’s nuclear scientists have had every incentive to do.
The Bridge That Could Work
The gap between “must leave Iran” (US) and “will never be transferred anywhere” (Iran) has two potential bridges. First, blending-down under IAEA verification: Iran processes its HEU down to below 20% enrichment, confirmed by IAEA inspectors, effectively removing the weapons-grade risk without transferring material.
Second, third-party escrow on Iranian soil: an arrangement in which the HEU remains physically in Iran but is placed under international custody — IAEA-monitored storage with both US and IAEA keyholders — that prevents Iranian access without triggering the sovereignty issue of removal.
Neither bridge is simple. But both are preferable to the military removal option that would require thousands of US ground troops and uncertain success, and both are preferable to a deal that leaves the HEU as a live proliferation risk.
Trump’s signal Tuesday that he is “OK with 20-year suspension if there’s a real guarantee” — combined with Iran’s offer to blend down rather than transfer — points toward the specific HEU architecture that makes a deal possible without requiring either side to fully abandon its stated position.
