Recent military activity around the Zaporizhia NPP (ZNPP) has underscored the continuing serious risks to nuclear safety and security at the site, with a deadly drone explosion affecting plant personnel this week and the plant today losing all external power, International Atomic Energy Agency (IAEA) Director General Rafael Mariano Grossi said.
In recent days, the IAEA team at the ZNPP have continued to hear military activity, including explosions and drone activity, several times a day often at distances that appeared to be close to the site.
The 330 kV Ferosplavnaya-1 power line – the plant’s only remaining off-site power line – was disconnected and the location of the damage to the line was preliminarily assessed to be on the northern bank of the Dnipro River. An attempt to reconnect the line manually was unsuccessful, and, due to ongoing military activity, technicians were unable to determine the cause of the outage. The ZNPP confirmed that all available emergency diesel generators automatically started up to power the plant’s vital safety systems. After startup, some generators were returned to standby mode in line with operational requirements, leaving seven emergency diesel generators in operation.
“Each loss of off-site power underscores the extremely fragile nuclear safety and security situation at the ZNPP,” Director General Grossi said, repeating his call for maximum military restraint and for the protection of the plant’s external power supply.
The IAEA team has also continued to follow developments related to the site’s used fuel pools and diesel fuel supplies. With the 750 kV Dneprovskaya line unavailable for an extended period and military activity in the area continuing to hamper efforts to replenish the site’s diesel fuel stores, the ZNPP decided to increase the water levels in the spent fuel pools of all six reactor units.
The IAEA team observed work under way at all six units to implement this measure, including monitoring for possible leaks from the increased water levels. Increasing the water in the used fuel pools gives the site more time before boiling could occur, thereby strengthening safety margins in the event of an extended loss of off-site power during which diesel fuel supplies became exhausted and cooling could not be maintained.
The ZNPP also informed the IAEA team this week that its most recent delivery of diesel fuel to the site’s fuel farm took place in March 2026. A further delivery, planned for May, remains delayed due to frequent military activity in the area. The plant continues to report that it has more than ten days of diesel fuel available on site to operate its emergency diesel generators if needed.
ZNPP said on its Telegram channel that, after the loss of external power supply, the power units were automatically switched to power from backup diesel generators. “The equipment worked normally, and there were no violations in the operation of the security systems. The station staff controls the operating parameters of the equipment. All necessary measures to maintain the safe condition of the power units are being taken in full. The radiation background at the ZNPP site and in the observation area is within the natural values and does not exceed the established standards. The situation is under constant monitoring by the station’s specialists.”
Plant Director Yuri Chernichuk, in an interview with the IS Vesti said that this was the 26th such incident since the start of the conflict. He added that the situation is difficult due to the prolonged hostilities against the station itself and the satellite city of Energodar. He noted that it is too early to call it an emergency situation, but it is already critical. He emphasised that a crisis could occur at any time, even if there was fuel available. The situation is now further aggravated because logistics have been difficult for about three months: the roads to Energodar and the NPP are under constant fire, and diesel fuel reserves are gradually dwindling.
