• Uranium enrichment means increasing the proportion of uranium-235 in uranium.
• Low enrichment is generally used for civilian nuclear fuel.
• Very high enrichment takes the material closer to weapons usability.
• This is why Iran’s enrichment programme is the most sensitive part of its nuclear programme.
Main facilities
• Natanz is one of Iran’s principal enrichment centres.
• Fordow is another major enrichment facility and is heavily protected underground.
• Isfahan is important in the wider nuclear fuel cycle, especially uranium conversion and related fuel-processing infrastructure.
• In June 2025, the IAEA said Fordow was Iran’s main site for enrichment up to 60%.
Why the programme became controversial
• Iran says its nuclear programme is for peaceful purposes.
• The problem is that enrichment technology is dual-use.
• The same enrichment process used for reactor fuel can also be pushed further toward weapons-grade material.
• So the international concern is not just whether Iran enriches uranium, but how much, where, and to what level.
JCPOA and later expansion
• The 2015 JCPOA tried to place limits on Iran’s enrichment levels, stockpiles, and centrifuge activity.
• It was endorsed through UNSC Resolution 2231.
• After the deal weakened, Iran gradually moved beyond those limits.
• It increased enrichment levels and expanded advanced centrifuge use.
• This made the enrichment issue central again in global diplomacy.
Latest known position before monitoring broke down
• As of 17 May 2025, the IAEA estimated Iran’s total enriched uranium stockpile at 9,247.6 kg.
• Reuters reported in April 2026, citing the IAEA, that before the June 2025 attacks Iran had 440.9 kg of uranium enriched up to 60%.
June 2025 attacks and their impact
• In June 2025, major military attacks hit Iranian nuclear sites.
• The IAEA said the above-ground part of Natanz’s Pilot Fuel Enrichment Plant was destroyed.
• Buildings at Isfahan were also damaged, including the uranium conversion plant.
• By February 2026, the IAEA reported that verification activities had stopped after the attacks and inspectors had been withdrawn for safety reasons.
Why this matters now
• The biggest issue now is not only Iran’s enrichment capability.
• It is also the loss of reliable international monitoring after June 2025.
• That has increased uncertainty about the exact condition of facilities and the location of enriched stockpiles.
• So the programme has become both a technical nuclear issue and a verification crisis.
