Bloomberg: US strikes spare key Iranian nuclear reactors at Isfahan

Despite a wave of American airstrikes targeting Iran’s nuclear program, US military planners deliberately avoided hitting operational reactors at the Isfahan Nuclear Technology and Research Center, according to satellite images and international nuclear inspectors.

Three research reactors at the site — including a miniature neutron source reactor fueled with bomb-grade uranium — remain intact, the International Atomic Energy Agency (IAEA) confirmed in its latest damage report, Caliber.Az reports.

The restraint appears to have been intentional. Four senior officials in Vienna told Bloomberg that Isfahan’s reactors were left untouched to avoid setting a dangerous precedent of striking live nuclear facilities. The officials, who asked not to be named due to the sensitivity of the information, said images show the reactors unharmed, even as surrounding buildings suffered significant damage.

Earlier on June 23, the IAEA Board of Governors convened an emergency session in Vienna to discuss the escalating situation. Hitting an operational nuclear reactor, even if low powered like the ones at Isfahan, could set a grave precedent, the officials said.

Iran responded to the US strikes by launching missiles at an American air base in Qatar. According to Qatari officials, the missiles were intercepted with no reported casualties.

Meanwhile, American officials said the full assessment of the damage from President Donald Trump’s decision to join Israel in attacking Iranian nuclear targets will take time, but preliminary analysis suggests a clear intent to avoid radioactive fallout at Isfahan.

In addition to the strikes on Isfahan, US B-2 stealth bombers dropped Massive Ordnance Penetrators (GBU-57) on Iran’s underground enrichment facilities in Natanz and Fordow. Satellite images from June 22, released by Maxar Technologies, show craters, collapsed tunnel entrances, and holes on a mountain ridge above the Fordow complex.

“The three sites targeted by the United States — also including Isfahan and Natanz — contained nuclear material in the form of uranium enriched to different levels, which may cause radioactive and chemical contamination within the facilities that were hit,” IAEA Director General Rafael Mariano Grossi said on June 22.

So far, the environmental impact of the strikes remains localised, the IAEA reported. A direct hit on Iran’s sole operating power reactor at Bushehr, officials warned, would have posed “the most serious” risk due to the potential for widespread radioactive release.

“While striking Isfahan’s operating units wouldn’t result in the same level of catastrophe, it would mark another significant escalation in the conflict,” the IAEA said.

In the aftermath of the strikes, renewed concerns surfaced over the fate of Iran’s highly enriched uranium stockpile.

“US attacks have delivered a fundamental and irreparable blow to the international non-proliferation regime conclusively demonstrating that the existing Non-Proliferation Treaty framework has been rendered ineffective,” Iran’s IAEA envoy Reza Najafi told reporters.

The Non-Proliferation Treaty (NPT), established over 50 years ago, allows signatories like Iran access to civilian nuclear technologies on the condition they do not pursue nuclear weapons. The IAEA has now demanded that Tehran disclose the current location of its enriched uranium stocks — a demand that Iranian officials have yet to fully address.

Iranian engineers have used the Isfahan reactors for neutron activation analysis — a method with both military and civilian applications. While once used in the early stages of the US nuclear weapons program, today it also supports medical and industrial research.

One of the reactors is located near a recently damaged building surrounded by trees, where analysts believe senior scientists gathered after conducting experiments.

By Sabina Mammadli