Nuclear Enrichment Programme
Iran's uranium enrichment capability; 440 kg stockpile survived 2026 strikes, breakout timeline now weeks.
Last refreshed: 31 March 2026
If bombs cannot eliminate the stockpile, what does "preventing Iranian nuclear weapons" actually mean?
Latest on nuclear enrichment programme
- How much enriched uranium does Iran have?
- Iran held 440.9 kg of uranium enriched to 60% U-235 per pre-strike IAEA records. Enriched to 90%, that is enough for approximately seven nuclear devices.Source: IAEA / Rafael Grossi (CBS, 22 March 2026)
- Did the 2026 strikes destroy Iran's nuclear programme?
- IAEA Director General Grossi stated military action cannot eliminate the programme. Iran still holds its enriched uranium stockpile; inspectors have no current access to verify centrifuge status.Source: IAEA
- How close is Iran to building a nuclear weapon?
- Western intelligence estimates Iran's breakout timeline at weeks rather than months, given its 440.9 kg of 60%-enriched uranium. An NPT withdrawal bill in Parliament would remove remaining treaty constraints.Source: US intelligence / IAEA
- What is Iran's nuclear enrichment programme?
- Iran's enrichment programme produces uranium at various grades using centrifuge cascades at facilities including Natanz, Fordow, and Isfahan. Enrichment to 60% U-235 is far above civilian reactor requirements and close to weapons-grade 90%.
- Did Iran withdraw from the NPT in 2026?
- A bill to withdraw Iran from the Non-Proliferation Treaty was uploaded to Parliament as priority legislation in late March 2026. It had not yet passed as of that date.Source: Islamic Consultative Assembly portal
- How many nuclear facilities does Iran have?
- As of March 2026, Iran has four known enrichment facilities: Natanz, Fordow, and two at Isfahan (one newly disclosed). Inspectors have been denied access to all.Source: IAEA
- What enrichment level does Iran use for weapons?
- Weapons-grade uranium requires 90% enrichment. Iran has been enriching to 60%, which can be further enriched to weapons-grade in a relatively short additional step.Source: IAEA
Background
Iran's nuclear enrichment programme survived the 2025-26 US-Israeli air campaign in its most consequential dimension: the fissile stockpile. The IAEA confirmed Iran held 440.9 kg of uranium enriched to 60% U-235 in pre-strike inspection records. That stockpile, if further enriched to weapons-grade 90%, is sufficient for approximately seven nuclear devices. Inspectors have detected movement near stockpile sites but have had no access to enriched uranium inventories for over eight months. IAEA Director General Grossi concluded that military action cannot eliminate the programme: "the material will still be there and the enrichment capacities will be there."
Iran operates four known enrichment facilities: Natanz, Fordow, Isfahan (newly disclosed March 2026), and a fourth whose status is unverified. US and Israeli strikes hit Natanz twice, Fordow, and Isfahan using GBU-72 Advanced 5K Penetrators. Netanyahu claimed Iran "no longer has the capacity to enrich uranium" but provided no supporting evidence; the IAEA did not corroborate the claim.
A bill to withdraw Iran from the Non-Proliferation Treaty was filed in Parliament as priority legislation in late March 2026. If passed, all remaining JCPOA restrictions would lapse. Iran's breakout timeline to a first device, absent further strikes, is estimated by Western intelligence at weeks rather than months.
