PRIPYAT, UKRAINE — An explosion at 1:59 a.m. on Feb. 14, 2025, damaged the outer layer of the New Safe Confinement structure at the Chernobyl nuclear power plant, Ukrainian officials said. Ukrainian officials blamed a Russian drone carrying an explosive warhead for the strike. The drone started a fire but did not penetrate the structure, damaging an area with low contamination, and radiation monitors detected no increase in radiation levels outside the confinement.

A military checkpoint near Chernobyl confirmed the strike. Firefighters arrived about 40 minutes later, and the fire took more than two weeks to extinguish fully. No one was injured.

The New Safe Confinement, completed in 2019 at a cost of $2.1 billion, was built through global efforts to enclose the original sarcophagus covering Reactor No. 4 and to enable its eventual dismantling. The first explosion at the plant occurred at 1:23 a.m. on April 26, 1986, spreading a radiation cloud across Europe. The plant has not produced electricity since 2000, when its last reactor was shut down, and the surrounding exclusion zone covers 2,600 square kilometers and remains uninhabited.

The International Atomic Energy Agency found that the damage left the structure unable to fully perform its core functions of containing radioactive material and enabling safe dismantling, and warned that the damage could shorten the structure's 100-year lifespan. Left unrepaired, the confinement would gradually weaken, increasing radiation exposure risks to Ukraine and other countries, the agency said. Work on dismantling the sarcophagus is on hold and set back by at least a decade.

"There was no feeling of fear, none at all. It was just a fire — something we practice in drills — only this time it was real. I didn't think, honestly, that we could lose the entire arch." said Serhii Bokov, who oversees operations for the New Safe Confinement.

Oleh Solonenko, head of a radiation safety shift at Chernobyl, said: "What once seemed unthinkable — strikes on nuclear facilities and other hazardous sites — has now become reality."

Russian troops seized the Chernobyl plant in February 2022, and plant staff kept operations running under armed guard for nearly three weeks. Personnel were exposed to radiation doses beyond normal rotation limits during the occupation, with soldiers occupying key areas, causing staff to sleep on floors and desks. Russian troops also drove heavy vehicles through contaminated areas and dug trenches, stirring up radioactive dust. Russia's invasion has put the New Safe Confinement project on hold.

Eric Schmieman, an engineer, described the conditions the structure was designed to contain. "It is difficult to comprehend the scale of the deadly, hazardous conditions inside the sarcophagus. There are tons of highly radioactive nuclear fuel, dust and debris," he said.