Skip to content
Iran Conflict 2026
20APR

Fordow inoperable since June 2025 bunker-busters

4 min read
10:10UTC

The IAEA's April monitoring update, relayed by the American Nuclear Society, finds Fordow has not been reactivated since twelve GBU-57 bunker-busters disabled it in June 2025; the February 2026 strikes did not retarget the mountain site.

← Back to Two unsigned rulebooks collide at HormuzJump to analysis ↓
ConflictDeveloping
Key takeaway

Fordow has produced no enriched uranium since June 2025; the 2026 negotiating positions are priced against destroyed infrastructure.

The American Nuclear Society's 6 April 2026 relay of the IAEA Director-General's monitoring report confirms Fordow has not been reactivated since Operation Midnight Hammer on 22 June 2025 4. Twelve GBU-57 Massive Ordnance Penetrators, six per ventilation shaft across two shafts, were delivered by seven B-2 stealth bombers; Gen. Caine, Chairman of the Joint Chiefs, stated at the time that "all six weapons at each vent went exactly where they were intended to go." Satellite imagery shows tunnel portals remain backfilled, no heavy machinery has entered for reconstruction since late July 2025, and ventilation infrastructure is destroyed. Enrichment at Fordow is physically impossible while the shafts remain sealed.

Whether the MOP warheads actually penetrated the centrifuge cascade hall itself is contested. David Albright at the Institute for Science and International Security (ISIS) assesses the weapons "likely entered directly into the buried enrichment hall" based on satellite crater analysis; the IAEA, using "expected" rather than "confirmed" in its September 2025 monitoring report, declines to match that claim because no inspector has physically accessed Fordow since June 2025. The Arms Control Association notes the strategic effect, an inoperable facility, is not disputed by any credible source; the physical question is.

Natanz and Esfahan were destroyed in the same Twelve-Day War: Israel's Operation Rising Lion on 13 June 2025 struck Natanz's surface Pilot Fuel Enrichment Plant and cratered the underground cascade halls, while Esfahan's uranium metal conversion plant was destroyed in waves across 14 and 20-21 June. Midnight Hammer added two GBU-57s at Natanz (ISIS: "likely destroyed and knocked out of operation") and collapsed all four Esfahan tunnel entrances with Tomahawks. Esfahan's deeply buried storage, holding roughly 200 kg of 60%-enriched uranium, survived because even the MOP could not reach it; US strategy was access-denial, not destruction of the material itself .

Operation Roaring Lion / Epic Fury, the February 2026 campaign, did not retarget Fordow. Natanz took access-denial strikes on already-ruined entrances on 2-3 March and again on 21 March; the IAEA reported "no additional impact detected at FEP itself" because the underground halls had been out of service since June 2025. Iran's own foreign minister Abbas Araghchi conceded the point on 13 April, telling CBS that Iran cannot currently enrich uranium at any facility . The Majlis 221-0 suspension of IAEA cooperation on 11 April locks inspectors out of the residual questions (centrifuge hall breach, surface rebuild intent), but the first-order question, whether Fordow produces enriched uranium, was answered in June 2025.

Deep Analysis

In plain English

Iran has three main uranium enrichment sites: Natanz, Esfahan and Fordow. Natanz and Esfahan were destroyed in June 2025 by a combined Israeli and American air campaign known as the Twelve-Day War. Fordow, a plant dug about 80 metres inside a mountain near Qom specifically to survive air attack, was disabled in the same campaign when US B-2 bombers dropped twelve of the largest conventional bunker-busters in service down its two ventilation shafts. The April 2026 IAEA update, relayed by the American Nuclear Society, confirms Fordow has not been repaired or restarted since then. No centrifuges have spun, no uranium has been enriched. A separate February 2026 campaign struck access points at Natanz but did not attack Fordow, because Fordow was already out of action. This matters for the talks: both sides are negotiating over whether Iran should pause enrichment for 20 years or 3 to 5, but the physical capability to enrich is already broken.

Deep Analysis
Root Causes

Iran chose in 2007-2009 to build Fordow inside a mountain specifically because it anticipated exactly the kind of air campaign that arrived in June 2025. The mountain bought time against conventional munitions; it did not buy immunity against the GBU-57, the single weapon in the US inventory designed for this target. When **Midnight Hammer** delivered twelve MOPs to two ventilation shafts, the survivability doctrine that had protected Fordow through the Natanz (Stuxnet, 2010) and earlier sabotage waves reached its physical limit.

The April 2026 inspection lockout is a separate compounding cause. The **Majlis** 221-0 vote on 11 April removed the IAEA from Iran's territory just as the diplomatic track shifted to written positions. Without on-site access, the questions that separate "inoperable" from "destroyed", whether centrifuge halls were breached, whether surface supply chains can be repaired, whether enriched uranium remains recoverable, cannot be answered. The talks therefore negotiate on a capability assessment frozen at the last pre-lockout satellite pass.

What could happen next?
  • Consequence

    Washington's 20-year enrichment-pause demand now negotiates against an unverifiable baseline; any agreement struck before inspectors return to Fordow is structurally unverifiable.

  • Risk

    If the Munir mediation shuttle (ID:2498) produces a ceasefire extension without an inspection clause, Fordow's status becomes permanently unverifiable under the ceasefire architecture.

Sources:American Nuclear Society (relay of IAEA Director General report)
Mentions:IAEA →Fordow →Natanz Fuel Enrichment Plant →Isfahan →Majlis →Northwood →Arsenio Dominguez →GBU-57 Massive Ordnance Penetrator →Persian Gulf →Prima →North Korea →Libya →Iran →Arms Control Association →Saudi Arabia →UN Convention on the Law of the Sea →Oman →United States →Traffic Separation Scheme (TSS) →Gulf Cooperation Council (GCC) →Qom →American Nuclear Society →Operation Roaring Lion / Epic Fury →Twelve-Day War →Operation Midnight Hammer →Operation Rising Lion →Institute for Science and International Security →Gulf War →Al-Kibar →Defense Intelligence Agency →
First Reported In

Update #74 · Two unsigned rulebooks collide at Hormuz

American Nuclear Society (relay of IAEA Director General report)· 20 Apr 2026
Read original →
Different Perspectives
Global South governments (Indonesia, Brazil, South Africa)
Global South governments (Indonesia, Brazil, South Africa)
Neutrality was possible when the targets were military. 148 dead schoolgirls made it impossible — no government can explain that away to its own citizens.
Trump administration
Trump administration
Oscillating between claiming diplomatic progress and threatening escalation, while deploying additional ground forces to the Gulf.
Israeli security establishment
Israeli security establishment
Fears a rapid, vague US-Iran agreement that freezes military operations before the IDF achieves what it considers full strategic objectives. A senior military official assessed the campaign is 'halfway there' and needs several more weeks.
Iraqi government
Iraqi government
Iraq's force majeure is the position of a non-belligerent whose entire petroleum economy has been paralysed by a war between others — storage full, exports blocked, production being cut with no timeline for resumption.
Russia — Ambassador Vassily Nebenzia
Russia — Ambassador Vassily Nebenzia
Moscow calibrated its position between Gulf states and Iran: abstaining on Resolution 2817 rather than vetoing it, signalling it would not block protection for Gulf states, while refusing to endorse a text that ignores the US-Israeli campaign it regards as the conflict's proximate cause. Russia proposed its own ceasefire text — which failed 4-2-9 — allowing Moscow to claim the peacemaker role while providing Iran with satellite targeting intelligence, a duality consistent with its approach in Syria.
France — President Macron
France — President Macron
France absorbed its first combat death in a conflict it has publicly declined to join. The killing of Chief Warrant Officer Frion in Erbil forces Macron to choose between escalating involvement and accepting casualties from the margins.