VIENNA – Iran has continued to escalate its nuclear enrichment levels and restrict international oversight, following a period of increased military tension and the collapse of previous diplomatic agreements.
The program has remained a central point of contention in diplomatic negotiations and the catalyst for international sanctions. In February, the United States and Israel launched joint strikes against the country, an action Donald Trump attributed to the nature of the nuclear program.
While Tehran maintains that its nuclear activities are exclusively peaceful, the US and Israel have consistently rejected these claims, asserting that the program is a cover for the development of nuclear weapons.
Enrichment Thresholds and Weapons-Grade Uranium
The current state of the program marks a significant departure from the limits established under the 2015 nuclear deal, formally known as the Joint Comprehensive Plan of Action (JCPOA), which was endorsed by the UN Security Council through Resolution 2231. Under that agreement, enrichment was capped at a level suitable for commercial power generation and subject to extensive international verification.
The technical gap between commercial fuel and military capability is defined by the percentage of uranium-235 enrichment, a key metric for policymakers and inspectors assessing how quickly a state could move toward a nuclear weapon if it chose to do so:
- Commercial Nuclear Power: 3.67% enrichment (the 2015 limit)
- Current Iranian Levels: 60% enrichment (reported as of June)
- Weapons-Grade Uranium: 90% enrichment or higher
Following the US withdrawal from the 2015 agreement in 2018, Iran began increasing its enrichment levels in a series of declared steps, each framed by Tehran as a response to sanctions and non-compliance by other parties. By June, the International Atomic Energy Agency (IAEA) reported that Iran had amassed a stockpile of 400kg of uranium enriched to 60% – material that non-proliferation experts say significantly shortens the so‑called “breakout time,” or the period needed to produce enough weapons-grade material for a single warhead.
International Monitoring and Facility Access
The IAEA, the United Nations’ nuclear watchdog, is responsible for verifying that nuclear materials are not diverted to weapons programs under Iran’s safeguards agreement and the transparency measures previously applied under the JCPOA. However, the agency’s ability to monitor Iranian sites has become severely limited as Iran has curtailed access and disabled or removed some monitoring equipment.
Last week, the IAEA confirmed it had conducted a “routine inspection” at the Bushehr Nuclear Power Plant, the country’s primary commercial nuclear facility and the only plant currently producing electricity for the national grid. The inspection, carried out under longstanding safeguards obligations, allowed inspectors to verify declared fuel and operations but did not address the wider questions around Iran’s expanding enrichment work at other sites.
Despite this single access point, the agency reported that inspectors have been unable to access other nuclear facilities for nearly a year, including key enrichment plants where advanced centrifuges are installed. Diplomats say the erosion of on-the-ground visibility has left governments increasingly dependent on satellite imagery and intermittent IAEA reports, complicating efforts to calibrate sanctions, deterrence, and any potential return to negotiations.
With Tehran and Western capitals still publicly committed to diplomacy but far apart on sequencing sanctions relief and nuclear steps, the combination of higher enrichment levels and restricted monitoring is hardening positions on all sides and narrowing the space for a revised agreement to restore the limits once imposed by the JCPOA framework.
