The International Atomic Energy Agency (IAEA) last reported on June 13 that 409 kg of enriched uranium was present at the Isfahan nuclear site. Some of this stock has been enriched to 60%, well above the civilian threshold (2-3%), but still below the 90% needed to produce a nuclear weapon.

Tehran claims to have taken "special measures" to protect this stockpile, which can be easily moved within the dozen or so sites that make up its nuclear complex. But since a series of strikes carried out by the United States, the mystery remains: the enriched uranium is still nowhere to be found.

Limited or total success?

Following the underground bombing of Iranian infrastructure, Donald Trump assured that "the Iranian nuclear threat has been neutralized." However, the stockpile does not appear to have been affected, leading some experts to believe that the bombing of the Iranian military complex is not over.

For those who have grown up, grown old, or both, with the nuclear threat as a backdrop, the very idea of bombing real atomic sites is deeply disturbing. It is therefore essential to assess the risks.

The risk of a radiological disaster

An attack on an operating civilian reactor would be a major disaster. All experts agree that the consequences would be comparable to those of Chernobyl. But to this must be added the geopolitical consequences.

According to Alexei Likhachev, head of the Russian atomic energy agency Rosatom, reactors are being operated at the Bushehr site with Russian assistance, and new ones are being built.

The danger does not stop at Iran's borders. The neighboring Persian Gulf could see its waters contaminated. Several countries in the region, led by Qatar and Bahrain, depend on desalination for 100% of their fresh water supply. Saudi Arabia, Oman, and the United Arab Emirates are also highly dependent, although they have access to other maritime sources.

It is precisely to avoid such a scenario that Israel and the United States have so far spared the civilian site at Bushehr.

Priority targets: enrichment sites

The US military has struck sites in Fordo, Natanz, and Isfahan. Donald Trump claims that Iran's main enrichment facilities have been "completely and utterly destroyed." These attacks follow recent Israeli strikes on Natanz, Isfahan, Arak, and even Tehran.

The target is the heart of Iran's nuclear program. Infrastructure, scientists, conversion centers—everything is being targeted to hinder the enrichment process.

What is the immediate danger?

Low-enriched uranium is not very radioactive. The main risk comes from uranium hexafluoride (UF6), a highly toxic and corrosive gas used in enrichment. If leaked, it can react with moisture in the air, creating dangerous chemical compounds that are potentially lethal if inhaled.

However, the underground structure of the facilities limits dispersion. UF6 does not travel far, and the sites are often protected by massive layers of concrete, rock, and earth.

According to Simon Bennett, a specialist at the University of Leicester, the environmental risks remain "minimal" in the event of underground strikes. James Acton, of the Carnegie Endowment for International Peace, considers it "unlikely" that such attacks would have significant effects outside the targeted sites.

An increasingly blurred red line

Israel and the US insist that they want to avoid a radioactive disaster. However, tensions are rising. In mid-June, an alert issued by Israel about a strike on the civilian site in Bushehr, which ultimately proved unfounded, caused a stir. The red line seems to be getting closer every day.

The conflict seems far from over, even though Iran has been weakened. Its uranium stockpile remains untraceable. And the goal of destroying its nuclear capabilities has not yet been achieved.