On June 24, 2025, Bloomberg reported that the U.S. military deliberately avoided hitting buildings believed to house nuclear research reactors when it struck the Iranian nuclear center in Isfahan on June 22 as part of Operation Midnight Hammer. Citing satellite images and four senior sources in Vienna, the agency said the three reactors at the Isfahan Nuclear Technology Center, including a 1991 Chinese-made miniature neutron reactor fueled by 900 grams of weapons-grade uranium, were undamaged. The reactor vessels, which are under the supervision of the International Atomic Energy Agency (IAEA), were intact, while most of the large industrial buildings around them, including uranium conversion facilities, were destroyed.

The US attack, which The New York Times reported involved seven B-2 Spirit bombers dropping 14 GBU-57 bunker buster bombs and submarines firing more than 30 Tomahawk cruise missiles, hit three key Iranian nuclear sites: Fordow, Natanz and Isfahan. In Isfahan, CNN reported, satellite imagery from Maxar Technologies showed 18 destroyed or partially damaged structures, as well as significant debris and ash at the complex. IAEA Director General Rafael Grossi confirmed that buildings associated with uranium processing were damaged in Isfahan, but noted that there was no radioactive contamination, which is consistent with Iranian statements.

Iran says key enriched uranium stockpiles were evacuated from Isfahan, Natanz and Fordow before the strikes. Atomic Energy Organization of Iran (AEOI) spokesman Hassan Abedini said “enriched materials have been moved to a safe location,” minimizing the risk of radiation damage. However, satellite images released by the Institute for Science and International Security show the collapsed entrances to tunnels in Isfahan that were likely used to store uranium enriched to 20% and 60%.

The avoidance of hitting the reactors, according to experts cited by Bloomberg, is linked to the US desire to prevent a radiation catastrophe. Richard Wakeford, a professor at the University of Manchester, noted that an attack on an operating reactor like those in Isfahan could release radioactive material into the atmosphere or sea, creating an “absolute radiation catastrophe.” This is in line with the cautious approach Israel previously took, avoiding striking the Bushehr reactor in 1981 before it was loaded with fuel.

The U.S. attack prompted a response from Iran: On June 23, Tehran launched 14 missiles at the Al Udeid air base in Qatar and one at a base in Iraq as part of Operation Basharat al-Fatah. President Trump, commenting on the attack, thanked Iran for its “warning” that prevented casualties and called the response “weak,” calling for peace. Qatar said 13 of the missiles were intercepted and one was not a threat. The Wall Street Journal noted that Iran continues to move missile launchers in preparation for more strikes.