Iran’s nuclear program is the issue at the heart of the U.S.–Iran war — and the main reason a deal to reopen the Strait of Hormuz remains out of reach. After Israeli and U.S. strikes in June 2025 and a new war in 2026, much of Iran’s known enrichment infrastructure has been destroyed or badly damaged. But key questions remain unanswered: how much enriched uranium survived, where it is, and whether Iran could rebuild. Here is what is known.
Key takeaways
- Before June 2025, the IAEA estimated Iran had 440.9 kg of uranium enriched up to 60% — enough for about 10 weapons if enriched further.
- IAEA chief Rafael Grossi said in March 2026 that “a bit more than 200 kg” remains, mostly in tunnels at Isfahan, with some at Natanz.
- Natanz and Fordow are widely believed to be out of action; a tunnel site at Isfahan appears largely intact.
- IAEA inspectors have not been allowed back into the bombed sites.
A quick history
Iran says its nuclear program is for peaceful energy and medical purposes. Western governments have long suspected it was building the capability to make a bomb. The 2015 nuclear deal (the JCPOA) capped enrichment at 3.67% and gave the International Atomic Energy Agency (IAEA) extra inspection powers. After the U.S. withdrew in 2018, Iran expanded enrichment, eventually reaching 60% — a short technical step from the roughly 90% considered weapons-grade.
The June 2025 strikes
On June 13, 2025, Israel launched strikes on Iran, and the United States joined. During the 12-day campaign, the three enrichment facilities known to be operating were destroyed or badly damaged, according to Reuters reporting. The U.S. used heavy bunker-busting bombs against Fordow, a plant built deep inside a mountain near Qom. (Our video explainer looks at how analysts map bunkers under 80 meters of rock.)
The status of each site
- Natanz: The above-ground enrichment plant was destroyed; the underground plant was badly damaged and is widely thought to be out of action.
- Fordow: Badly damaged and widely thought to be out of action.
- Isfahan: Iran told the IAEA, the day before Israel’s June 2025 attack, that it was opening a new enrichment plant here. Diplomats say the tunnel complex appears largely unscathed, but the IAEA does not know the plant’s status.
Where is the enriched uranium?
This is the biggest unknown. Iran has not told the IAEA how much of its 60% stockpile survived or where it is. Grossi’s March 2026 estimate of a little more than 200 kg — mostly in Isfahan’s tunnels — suggests a significant amount could still exist. Since the JCPOA collapsed, the IAEA has also lost track of how many centrifuges Iran has and where they are. Reuters reported that Israel does not allege Iran is currently enriching uranium.
Why the nuclear issue blocks a deal
Iran wants the U.S. naval blockade, sanctions and regional hostilities resolved before any nuclear talks. Washington insists the nuclear program be part of a comprehensive settlement. President Trump has repeatedly said Iran will never be allowed to have a nuclear weapon, and Vice President JD Vance told Reuters this month that Iran must make a “meaningful” reduction in its enrichment capacity. Read more: Will the U.S. strike Iran after the midterms?
Could Iran build a bomb?
Experts generally point to three ingredients: enough highly enriched uranium, working centrifuges to raise it to weapons-grade, and the know-how to build and deliver a weapon. Strikes have damaged the second, but a surviving stockpile and hidden facilities could shorten any future timeline. Without inspectors, outside governments must rely on intelligence — which is why IAEA access is one of the most important issues in any negotiation.
Frequently asked questions
Does Iran have a nuclear weapon?
There is no public evidence that Iran has built a nuclear weapon. It has enriched uranium to 60%, close to weapons-grade.
How much enriched uranium does Iran have?
Before the June 2025 strikes, about 440.9 kg at up to 60%. The IAEA estimated in March 2026 that a little more than 200 kg remains.
Was Fordow destroyed?
Fordow was badly damaged in the June 2025 strikes and is widely thought to be out of action, but inspectors have not been able to verify its condition.
Information current as of late October 2026.
