PRIPYAT, Ukraine — A Russian drone attack on Chernobyl’s protective structure has revived fears among workers who have spent years trying to keep the site stable despite war, they said. The strike on Feb. 14, 2025, hit the outer layer of the New Safe Confinement, an archlike cover built to surround the damaged Reactor No. 4 and limit the spread of radiation. While Ukrainian officials and plant monitors reported no injuries and said radiation levels outside the arch did not rise, workers described the incident as a reminder that the conflict has upended long-standing nuclear-safety assumptions.
The Chernobyl site’s history stretches back to the night of April 26, 1986, when explosions at Reactor No. 4 spread a cloud of deadly radiation and triggered fears across Europe. The Feb. 14, 2025, attack came decades later and, according to Ukrainian officials, involved a Russian drone with an explosive warhead. “What once seemed unthinkable — strikes on nuclear facilities and other hazardous sites — has now become reality,” said Oleh Solonenko, head of a radiation safety shift at Chernobyl, which Ukrainians transliterate as Chornobyl.
Solonenko said the drone struck the NSC but did not fully penetrate it. He said the damage occurred in an area with low contamination, monitors detected no rise in radiation levels outside the arch, and no one was injured. Russia denied targeting the plant and alleged that Kyiv staged the attack. Despite those findings, Solonenko and others said the event showed how the war has disrupted the ability to plan and maintain nuclear safety over the long term.
The protective NSC was completed in 2019 as a $2.1 billion project designed to enclose the original concrete “sarcophagus” and prevent the damaged reactor’s deadly debris from leaking radiation. The International Atomic Energy Agency warned that the drone-caused damage could significantly shorten the arch’s 100-year lifespan and affect the structure’s core safety function. Plant officials said the incident left the arch unable to fully perform those functions, including containing radioactive material and enabling the safe dismantling of the reactor remains.
For Klavdiia Omelchenko, who has worked with more than 2,200 engineers, scientists and others at the defunct plant, the drone strike brought back memories of 1986. She was a 19-year-old textile factory worker in Pripyat, where many Chernobyl employees lived, and she said she did not hear the Reactor No. 4 explosion during a routine test. She recalled that authorities initially did not reveal the full scope of what became known as the world’s worst nuclear disaster, and that she later understood the scale after being evacuated with a bag holding her documents and cosmetics. Omelchenko said she later returned to work in the plant’s cafeteria and that her current fear centers on the war and what it means for the site’s safety rather than on contamination risks.
Other workers described how the war has already complicated everyday operations at the NSC. Liudmyla Kozak, an engineer who has worked at Chernobyl for more than two decades, said she was on duty when Russian troops seized the plant in February 2022. She said the staff kept operations running under armed guard for nearly three weeks, exposing personnel to radiation doses beyond normal rotation limits. Kozak said Russian troops damaged and stole equipment and stirred up radioactive dust by driving heavy vehicles through contaminated areas and digging trenches.
Serhii Bokov, who oversees operations for the NSC, said he was on duty early on Feb. 14, 2025, when the drone attack’s blast rippled through the structure. He said he and colleagues ran outside, smelling smoke, but initially saw nothing; a nearby military checkpoint confirmed a strike, and firefighters arrived about 40 minutes later. Bokov said crews climbed into the NSC and found a fire smoldering through the outer membrane, with hoses stretched across the arch as flames repeatedly resurfaced. He said the fire took more than two weeks to extinguish fully.
Bokov said the damage was patched and hidden on the inside while a sealed breach remained visible on the outside. Each night, he said he walks more than a kilometer through the NSC via what workers call the “golden corridor,” a passageway lined with yellow panels that shield them from radiation. When the NSC was completed in 2019, Bokov said he was proud of being part of a project that stabilized the site and enabled dismantling plans, but he said the structure is no longer fully sealed and dismantling work is on hold, setting back the process by at least a decade, in his view.
The plant’s radiation-safety officials said the drone strike damaged the NSC’s outer layer but did not fully penetrate it, with no detected rise in radiation levels beyond the arch. Greenpeace Ukraine, in a report by engineer Eric Schmieman who spent years at Chernobyl and helped design the NSC, warned that without urgent repairs the risk of the sarcophagus collapsing significantly increases. Schmieman said it is difficult to comprehend the scale of the deadly, hazardous conditions inside the sarcophagus and that it is critical to restore the NSC’s key functions.
AP reporters Vasilisa Stepanenko and Volodymyr Yurchuk in Kyiv contributed. The Associated Press receives support for nuclear security coverage from the Outrider Foundation. The AP is solely responsible for all content.