Inside the Urgent Race to Secure Ukraine’s Nuclear Plants

Rafael Mariano Grossi was awakened in the predawn hours Friday with an urgent crisis. A massive blaze was engulfing a building at the site of Europe’s largest nuclear power plant as Russian and Ukrainian forces fought nearby. Word had already spread around the globe, fueling fears that the reactor on the site might be damaged and spew radiation across Eastern Europe. It fell to Grossi, as head of the International Atomic Energy Agency (IAEA) to find out what was happening.

Grossi was patched through to the IAEA’s 24-hour Center for Incidents and Emergencies for the latest. The agency, which reports to the United Nations, was in-touch with workers at the Zaporizhzhya Nuclear Power Plant in southeastern Ukraine. Radiation levels were normal. Grossi relayed the information to Ukrainian and Russian politicians, whom he called soon after, urging them to halt the hostilities.

But in those conversations, he discovered that what was happening at Zaporizhzhya was no accident. A Russian government official told Grossi that the military was seizing the power plant to “prevent acts of sabotage” or terrorism. Ukraine, for its part, fears that the attack is an opening salvo in Russia’s goal to control their power grid. The Zaporizhzhya plant can generate enough energy to illuminate 4 million homes and accounts for one-fifth of the average annual electricity production in Ukraine.

When the clash ended and the fire was extinguished, the Russian military emerged in control. The facility had been damaged by a “projectile,” Grossi said, but the plant’s critical equipment remained intact. There was no radioactive leak, nor a risk for meltdown. Yet the situation was anything but reassuring. “This is unprecedented,” Grossi tells TIME. “We’ve never had armed conflict, in this way, with boots on the ground in a country with this configuration of nuclear infrastructure.”

With four plants that contain 15 reactors, Ukraine relies heavily on nuclear power for its electricity. To minimize the risk of a nuclear catastrophe amid the continuing fighting, Grossi is pressing the Ukrainian and Russian governments to begin diplomatic talks in Ukraine to make sure the battle for Zaporizhzhya is not repeated elsewhere around the country. “I hope and pray that these negotiations are successful,” he said. “We need to ensure the physical integrity of all the facilities in the country.”

Nuclear power plants, self-evidently, are not designed to be in active war zones. A misplaced artillery shell or free-falling bomb at any of these facilities holds the potential to create a humanitarian disaster that could spread well beyond Ukraine’s borders. In addition to power plants, there are three smaller research reactors and waste storage facilities spread throughout Ukraine, including in the besieged capital of Kyiv.

On Sunday, Russian missiles hit one of those disposal facilities in Kyiv. The day before, an electrical transformer was damaged at another disposal facility near Ukraine’s second largest city, Kharkiv. Fortunately, there hasn’t been any radioactive release, Grossi said, but all these incidents highlight the risk for human health and the environment. “What we saw last night is something that could occur again,” he said.

When Russian President Vladimir Putin announced the Feb. 24 offensive into Ukraine, one of his stated goals was to overthrow the government in Kyiv. U.S. intelligence hasn’t drawn firm conclusions as to why Russia is moving on these power facilities, but they believe it serves Russia’s overarching strategy in Ukraine. “If your goal is to control Ukraine, one can surmise that you would want to control the infrastructure and to make sure that you can meter it to your needs,” said a senior U.S. defense official who was not authorized to speak publicly about the matter. “So a nuclear power plant would certainly be on that list.”

Days before the Russian attack, Ukrainian civilians in the city of Enerhodar blocked a road to prevent Russian troops from reaching the nuclear power plant. As crowds of citizens gathered, Russian forces were later seen opening fire.

The battle for Zaporizhzhya was observed in real-time. Tens of thousands of people watched in horror as the facility’s security cameras streamed footage of the gunfight live on YouTube. Video showed clouds of black smoke rising and flames licking outside the building. Soldiers were seen exchanging fire, while others were seen being carted away injured or possibly dead. For those not watching, Ukraine’s foreign minister Dmytro Kuleba took to Twitter, invoking the 1986 nuclear disaster that took place in the north of the country, and warning of the current danger: “If it blows up, it will be 10 times larger than Chernobyl! Russians must IMMEDIATELY cease the fire, allow firefighters, establish a security zone!”

While the plant was burning, U.S. President Joe Biden and British Prime Minister Boris Johnson spoke with Ukrainian President Volodymyr Zelensky about the safety of the facility. The Russian military incursion drew worldwide condemnation. “We survived a night that could have stopped the story, the history of Ukraine, the history of Europe,” Zelensky said. “Russian tank commanders knew what they were firing at… The terrorist state now resorted to nuclear terror.”

In a nuclear reactor, fuel rods are inserted close enough together to start a process called nuclear fission, which generates tremendous amounts of heat. It is cooled by pushing water past the nuclear core and carrying the heat somewhere else. If the fuel overheats, it could release radioactive contamination into the environment.

Zaporizhzhya utilizes a pressurized water reactor known as a VVER model, which is designed to withstand damage, including natural disasters. An attack could cause damage to critical cooling pumps, pipes and other systems but the reactor is encased in reinforced concrete. In February, the chief executive of Energoatom, the company that operates Ukraine’s nuclear power plants, said the power units could even withstand an aircraft crash, according to a World Nuclear Association report.

Grossi said the safety systems of the plant’s six reactors had not been affected. The “projectile,” likely an artillery shell, hit a training building near one of the plant’s reactor units, sparking the fire that was later extinguished. “The worst case scenario will of course, be an accident… that would break the containment, the control and the cooling systems,” he said.

Indeed. When the nuclear reactor at the Chernobyl nuclear plant exploded near the Ukrainian city of Pripyat in April 1986, the fire burned for 10 days. Radioactivity was detected in Europe as far as Ireland and Greece. A 20-mile exclusion zone has remained in-place even as Russia sent in columns of military forces and equipment to take over the decommissioned power plant in the opening days of the invasion last week.

Grossi, 61, said he told Russian and Ukrainian officials that he was willing to immediately travel to Chernobyl to secure a commitment to measures guaranteeing the safety of nuclear sites. If such a meeting were to take place, Grossi said, he would not touch on the political aspects of the war, rather he sees the need to limit the clear nuclear dangers.

Grossi, a former Argentine diplomat, said he feels it is necessary to be in the country in-person. He also wants to ensure the plant’s highly trained staff is getting rest and not operating the facility under the barrel of a gun. “As IAEA Director General, I could not send my people in harm’s way without going myself first,” he said.

“It is high time to stop an armed conflict from putting nuclear facilities at severe risk, potentially endangering the safety of people and the environment in Ukraine and beyond,” Grossi said. “Words must mean something—it is time for action.”