IAEA Director-General Rafael Grossi on Monday told the IAEA Board of Governors that Israel had failed to destroy Iran's uranium-enriching centrifuge fleet at an underground facility at Natanz.

He acknowledged that the IDF had succeeded in destroying the above-ground Natanz nuclear sites, damaging the electrical grid that runs the underground centrifuges, and causing contamination of the underground facility.

Responding, IDF sources said that they believe Grossi is wrong.

Previously, the IDF had said that it had succeeded in striking and destroying both the above-ground and underground Natanz nuclear sites, including the crucial centrifuge fleet.

Grossi: No additional damage at Natanz since Friday attack

Grossi told the Board, "There has been no additional damage at the Natanz Fuel Enrichment Plant site since the Friday attack, which destroyed the above-ground part of the Pilot Fuel Enrichment Plant, one of the plants at which Iran was producing uranium enriched up to 60% U-235."

Next, he stated, "Electricity infrastructure at the facility, which included an electrical sub-station, a main electric power supply building, and emergency power supply and back-up generators, was also destroyed."

IAEA board and chief Rafael Grossi hold exceptional meeting about Israel's strikes on Iran, June 16, 2025 (credit: REUTERS/ELISABETH MANDL)
IAEA board and chief Rafael Grossi hold exceptional meeting about Israel's strikes on Iran, June 16, 2025 (credit: REUTERS/ELISABETH MANDL)
"There has been no indication of a physical attack on the underground cascade hall containing part of the Pilot Fuel Enrichment Plant and the main Fuel Enrichment Plant. However, the loss of power to the cascade hall may have damaged the centrifuges there," he reported.

Moreover, he said, "The level of radioactivity outside the Natanz site has remained unchanged and at normal levels, indicating no external radiological impact to the population or the environment from this event."

In addition, Grossi said, "Within the Natanz facility, there is both radiological and chemical contamination. Considering the type of nuclear material at this facility, it is possible that Uranium isotopes contained in Uranium Hexafluoride, Uranyl Fluoride, and Hydrogen Fluoride are dispersed inside the facility."

Also, the IAEA chief explained that, "The radiation, primarily consisting of alpha particles, poses a significant danger if Uranium is inhaled or ingested. However, this risk can be effectively managed with appropriate protective measures, such as using respiratory protection devices while inside the affected facilities. The main concern inside the facility is the chemical toxicity of the Uranium Hexafluoride and the fluoride compounds generated at the contact with water."

Busher, Tehran nuclear reactors not targeted 

Moving on from Natanz, Grossi stated that, "No damage has been seen at the site of the Fordow Fuel Enrichment Plant or at the Khondab heavy water reactor, which is under construction. Bushehr nuclear power plant has not been targeted nor affected by the recent attacks, and neither has the Tehran Research Reactor."

Next, he noted, "At the Esfahan nuclear site, four buildings were damaged in Friday’s attack: the central chemical laboratory, a uranium conversion plant, the Tehran reactor fuel manufacturing plant, and the UF4 to EU metal processing facility, which was under construction. As in Natanz, off-site radiation levels remain unchanged."