It’s a theoretical worst-case scenario, but one that feels uncomfortably close to becoming reality.
In the course of their ongoing war, Russian or Ukrainian forces strike a nuclear power plant. The reactor vessel at that facility is hit, either accidentally or intentionally, sparking a catastrophe that analysts warn could be “worse than Chernobyl,” the infamous 1986 disaster that led to thousands of deaths, scores more long-term illnesses, and caused such off-the-charts radioactive contamination that portions of northern Ukraine are still cordoned off to the public nearly 40 years later.
The Russia-Ukraine conflict, in many ways, has brought the planet closer to another near-apocalyptic nuclear incident than any other clash in recent history.
On Aug. 24, Russia said that a Ukrainian drone attack sparked a fire at a nuclear power plant in Russia’s western Kursk region, though Ukrainian officials did not publicly take responsibility for the assault.
Soon afterwards, the International Atomic Energy Agency confirmed in social media posts that a transformer at the site had caught fire “due to military activity.” It said that radiation levels in the area were at normal levels.
Because that apparent attack hit the plant’s transformer, analysts say, the danger of a major nuclear incident was low. But had the assault struck the plant’s reactor vessel — the cylinder that houses the nuclear fuel powering the reactor core — the results could have been far different.
Specialists also say that generally speaking, attacks on nuclear power plants like the one in Kursk are far more dangerous than, for example, military strikes on enrichment facilities, such as the Iranian sites bombed by American warplanes in June.
“That poses a lot less of a radiological risk, some chemical risk, isolated to humans around those facilities. But attacks against power plants are fundamentally different,” said Joseph Rodgers, deputy director of the Project on Nuclear Issues at the Center for Strategic and International Studies.
“Nuclear power plants contain very high levels of radiation when they’re operating,” he said. “The attack we saw by, probably, Ukrainian forces against the Kursk plant, it seems that the drone struck a power transformer, which is important, but it’s not the same as an attack on a reactor vessel. The power transformer basically takes the power that the nuclear reactor is creating and pushes it over long distances so it can get to people’s houses.”
“If there’s a massive attack against the reactor vessel or multiple reactors, especially at Kursk, where there’s two at any given time that are operational … You could have an instance worse than Chernobyl,” Mr. Rodgers said.
The Kursk plant cut its power output in half following the incident.
The facility has long been on the radar of the world’s top nuclear safety officials. In August 2024, as Ukrainian forces launched an offensive in Russia’s Kursk region, International Atomic Energy Agency director-general Rafael Grossi led a delegation of inspectors to the facility and said he was taking “very seriously” the risk of a major nuclear incident.
Kursk isn’t the only site of potential disaster. Just this week, the IAEA said it received new details about a dam constructed at the Zaporizhzhya Nuclear Power Plant in Ukraine to secure cooling water supplies there.
The facility, the largest nuclear power plant in Europe, has been in a cold shutdown since the spring of 2024 amid clashes in the area.
There have been multiple strikes around the plant, including some that damaged the facility’s power lines.
Russian forces took control of the Zaporizhzhya plant in the early days of the war. The IAEA, which has safety teams stationed at nuclear power plants across the war zone, is also on the ground at Zaporizhzhya but said it has been denied access to the new dam. IAEA officials are doing other work at the site, such as maintenance on safety systems and the site’s electrical systems and equipment, including the backup power transformers.
“Our access to this dam is essential to assess the cooling water situation which is crucial given the fragile nuclear safety situation at” Zaporizhzhya, Mr. Grossi said in an Aug. 28 statement.
The IAEA has had a permanent presence at all Ukrainian power plants since January 2023, including at Chernobyl. In February, a drone struck the roof of Chernobyl’s New Safe Confinement, built to contain the radioactive remains of one of the facility’s reactors, according to information compiled by the World Nuclear Association. Officials said that while the structure suffered some damage, radiation levels in the area remained stable.
Technically speaking, attacks on civilian nuclear power plants are banned under international law. In a detailed 2022 blog post explaining the legalities around such attacks, the International Committee of the Red Cross said that the Geneva Convention prohibits those kinds of military operations.
“Nuclear power plants are civilian objects, and as such are protected against direct attack and reprisals.
In case of doubt whether a nuclear power plant is being used to make an effective contribution to military action, it must be presumed to be civilian, even in contact areas,” the organization said.
Still, it’s clear that nuclear power plants are still being caught in the crossfire. One of the lasting effects of the Russia–Ukraine war could be a reimagining of safety protocols and protection measures at such facilities.
Mr. Rodgers, the CSIS analyst, said the IAEA under Mr. Grossi’s leadership is already reassessing how to protect nuclear power plants in war zones and is considering whether new safety standards need to be implemented to limit fallout even if they’re struck.
“It’s something we really haven’t had to think about in the absence of a major great power war,” Mr. Rodgers said. “We haven’t really thought very directly about the ways nuclear power plants could be targeted. So, this is a very timely issue.”
