Ukraine's Zaporizhzhya Nuclear Power Plant (ZNPP) lost all off-site power yesterday, marking the tenth time the plant has faced a complete loss of off-site power since the start of the conflict in February 2022. The incident once again underlines the extremely fragile nuclear safety and security situation at the plant, IAEA Director General Grossi said yesterday. 

The IAEA team based at the ZNPP reported that the ZNPP confirmed the disconnection from its last remaining 750kV external main power line at 16:56 local time yesterday. This was confirmed separately by the Ukrainian regulatory body. Following this power loss, the team observed that emergency diesel generators (EDGs) started operating to supply the plant with power – the ZNPP later confirmed that all available EDGs had started. 

The ZNPP has been reliant on one single off-site power line to power the pumps used to  cool its six reactors and their spent fuel, almost five months after it lost the connection to its last 330 kV back-up power line. The ZNPP last faced a complete loss of off-site power on 4 July 2025 when the plant relied on diesel generators for almost four hours.

“It is deeply concerning that the Zaporizhzhya Nuclear Power Plant, Europe’s largest nuclear power plant, has once again been cut off from all external power. The site, which is located on the front line, continues to be endangered. Each loss of power poses a real risk to nuclear safety and increases the likelihood of a nuclear accident,” added Director General Grossi. 

Following the loss of power on 4 July 2025, the IAEA team based at the ZNPP site was informed that the EDG fuel tanks were replenished with enough fuel to enable operation of emergency diesel generators for approximately 20 days, in case of a loss of another off-site power event. The team is investigating the cause of yesterday’s loss of power.