What happens when a nuclear site is hit?

per second A month after the US-Iran war, the conflict in the Gulf continues to escalate, as air strikes expand, oil markets react, and pressures mount around the Strait of Hormuz. But beyond the immediate security and economic concerns, another question is quietly taking shape: What actually happens if a nuclear site is bombed?

In most cases, even if a nuclear facility is struck, a large-scale radiation disaster is unlikely. Modern sites are designed with multiple safety systems that can shut down the reactors and contain the damage.

Risk is not determined by the strike itself, but by the damage the strike causes within the facility. However, the risk becomes much greater if these systems fail, or if an operating nuclear power plant is directly affected.

Where the danger begins

On February 28, when the United States and Israel launched a coordinated military campaign against Iranian leadership and military infrastructure, Iranian nuclear sites and ballistic missile sites were identified as potential targets. As the conflict deepened, Iranian officials reported strikes on the Natanz nuclear facility, a major uranium enrichment complex, located about 140 miles from Tehran.

This was followed by strikes on the Ardakan facility as well as the Khondab heavy water reactor, which was left inoperable after the attack. Earlier this week, additional heavy bunker-busting bombs were launched in Isfahan, close to the Isfahan Nuclear Technology Center.

So far, international monitoring bodies have reported no radiation leaks from the targeted facilities. The International Atomic Energy Agency said there was no indication of off-site contamination, even after reports of strikes on sites such as Natanz and near Isfahan.

But concern is not limited to the site of impact.

Throughout the Gulf, risks are shaped by geography and infrastructure. Much of the region relies on desalinated seawater, systems drawn directly from the sea. If radioactive materials enter marine environments, they will spread not only through ecosystems but through the infrastructure that provides drinking water to millions.

The Bushehr nuclear power plant, located along the Iranian Gulf coast, is located in close proximity to neighboring countries. Although not directly affected, experts have repeatedly warned that any escalation involving coastal nuclear infrastructure could have transnational consequences.

What happens next

Not every strike on a nuclear site results in a dramatic mushroom cloud explosion or immediate radiation release. What matters is where the site was hit and how much its safety systems were damaged.

Within minutes of impact, the reactor is designed to shut down automatically. This stops the nuclear reaction and acts as the first line of defense. But lockdown does not remove the risk.

The reactor core continues to generate heat through radioactive decay, and that heat must be controlled. The extent of the damage – whether to buildings, control systems or backup infrastructure – determines the effectiveness of these safety mechanisms in continuing to operate.

In past incidents, including the Fukushima Daiichi nuclear disaster in Japan, the shutdown process has been implemented as intended. The crisis did not begin until the tsunami disrupted vital systems in the hours that followed.

An Iranian woman walks near the view of the Tehran Research Reactor in Tehran.

Photo: Mortada Nikobazl/Getty Images