Skip to content
Briefings are running a touch slower this week while we rebuild the foundations.See roadmap
Iran Conflict 2026
25MAY

IAEA: 441kg enriched uranium untracked

2 min read
13:55UTC

The UN nuclear watchdog disclosed that 440 kg of weapons-grade-threshold uranium has been unverified for eight months, with movement detected near stockpile sites.

← Back to Two markets, two prices on one Iran dealJump to analysis ↓
ConflictDeveloping
Key takeaway

The enriched uranium is unaccounted for; the "degraded programme" narrative is incomplete.

IAEA Director General Rafael Grossi told CBS Face the Nation on 22 March that Iran possessed 440.9 kg of uranium enriched to 60% U-235 according to pre-strike inspection records. At 60% enrichment, that is enough fissile material for approximately seven nuclear weapons if further enriched to weapons-grade 90%. 1

Inspectors have had no access to previously declared inventories for more than eight months. Iran suspended cooperation with the IAEA and restricted inspectors from bombed sites. The agency detected "movement near stockpile sites" but cannot verify what has moved or where. Most of the stockpile is believed buried in tunnels at Isfahan.

Grossi put it plainly: "You cannot unlearn what you've learned." Iran retains the scientific and industrial base to rebuild. Netanyahu had claimed Iran can no longer enrich uranium , but the IAEA disclosed that same week that Iran has a new underground enrichment facility at Isfahan, its fourth, with inspectors denied access. The centrifuge infrastructure may be degraded. The enriched material itself is a separate question, and it remains unanswered.

Deep Analysis

In plain English

Before the war began, UN weapons inspectors had confirmed Iran held 440 kilograms of uranium enriched to 60% purity. To make a nuclear weapon you need uranium enriched to about 90%. At 60%, Iran's stockpile is not yet weapons-ready, but it is close: further enrichment would take weeks on available centrifuges. The problem is that inspectors have not been allowed to verify where this stockpile is for over eight months. The bombs and airstrikes have been aimed at enrichment machines and production facilities. The actual uranium material is something different. The IAEA, the UN body that tracks this, detected movement near storage sites but cannot say what moved or where it went. The public narrative is that US and Israeli strikes have set back Iran's nuclear programme. That may be true for the factories and machines. The 440 kilograms of already-processed uranium is a separate, unanswered question.

Deep Analysis
Root Causes

Iran's exclusion of IAEA inspectors began before the war, under the Joint Comprehensive Plan of Action breakdown from 2019 onward. By the time strikes began in February 2026, inspection access was already limited to declared sites. The war provided cover for restricting it further, but the verification gap predates the conflict.

The physical concealment is a separate driver. Iran's deep-tunnelling programme at Isfahan, Fordow, and Natanz was explicitly designed to move enriched material beyond the reach of bunker-busting munitions. The fourth underground facility disclosed by the IAEA in March 2026 suggests the dispersal architecture was built years in advance of the conflict.

What could happen next?
  • Risk

    If the 440 kg stockpile has been dispersed to undeclared sites, no future ceasefire agreement can verifiably denuclearise Iran without renewed IAEA access that Iran's five conditions make unlikely.

  • Consequence

    The 'degraded programme' narrative underpins domestic US public support for the war; the stockpile uncertainty undermines the achievement claim.

Sources:IAEA / CBS News·IAEA / CBS News
Mentions:Israel →Iran →Rafael Grossi →Isfahan →
First Reported In

Update #50 · Houthis join; Iran holds two chokepoints

IAEA / CBS News· 28 Mar 2026
Read original →
Causes and effects
This Event
IAEA: 441kg enriched uranium untracked
The dominant narrative that strikes have "set back" Iran's nuclear programme ignores that the existing enriched stockpile, enough for seven weapons, is unaccounted for.
Led to
Iran tables bill to leave NPT
Iran's 440 kg of 60%-enriched uranium unverified for eight months (ID:1659) was explicitly cited in parliamentary debate as proof the NPT provides no protection and no incentive to remain.
Occurred 28 Mar 2026
Read story →
Trump declares war won, orders pullout
IAEA's confirmed 440 kg unverified uranium (ID:1659) directly contradicts Trump's nuclear goal attained declaration.
Occurred 1 Apr 2026
Read story →
IAEA rejects Trump's war victory claim
IAEA's confirmed 440 kg unverified uranium (ID:1659) is the nuclear context for the IAEA disclaimer at the briefing's close.
Occurred 1 Apr 2026
Read story →
Grossi: 200 kg sealed in Isfahan
Grossi's 29 April tunnel assessment gives a specific underground location for the 440.9 kg stockpile he reported to CBS on 22 March (ID:1659) before the strikes; the tunnel concealment predates both that report and Israel's opening strikes.
Occurred 29 Apr 2026
Read story →
Different Perspectives
Lloyd's of London
Lloyd's of London
The Joint War Committee left Hormuz war-risk premiums at $10-14 million per voyage on 25 May, declining to move on Brent's 5% fall. The JWC's protocol requires a UN Security Council resolution or bilateral government certification letter before de-listing, and neither has arrived: a verbal understanding does not satisfy the formal condition the reinsurance market's treaty terms require.
Gulf Arab producers
Gulf Arab producers
Saudi Arabia and UAE depend on Hormuz for their own crude exports; Aramco CEO Nasser has warned no oil market recovery arrives until 2027 if the blockade continues past mid-June. Monday's $98.96 Brent settlement shortens nothing for Gulf producers without a signed instrument and a Pentagon mine-clearance timeline that runs up to six months post-ceasefire.
Qatar
Qatar
Qatar holds $12bn of frozen Iranian assets at the centre of the sequencing dispute but cannot release them without explicit US Treasury authorisation, given the original freeze was a US instrument. As the asset-holding state, Qatar's leverage is real but passive: it is the escrow holder, not the decision-maker, and any resolution requires US Treasury sign-off that Trump has withheld.
Pakistan
Pakistan
With both Prime Minister Sharif and army chief Munir simultaneously in Beijing on 25 May, Pakistan has for the first time consolidated its civilian and military mediation tracks under China's roof. Munir's direct Tehran-to-Beijing flight signals that the security and financial threads of the sequencing problem are now being worked in parallel rather than sequentially.
China
China
Beijing hosted Pakistan's principal mediators and Iran's China envoy Ghalibaf simultaneously on 25 May while its banking regulator capped new state-bank lending to five sanctioned refiners. China is simultaneously the most credible third-party underwriter of the $12bn sequencing and the state whose institutions face live OFAC secondary-sanctions exposure if the deadlock persists through GL V's expiry.
United States
United States
Trump posted on 24 May that the blockade holds until a deal is certified and signed, ruling out the informal MOU structure both sides had been building. The 'certified, and signed' condition is the first operational bar Trump has attached in 87 days, but it arrived without an executive instrument, maintaining the gap between posted ultimatum and signed US policy.