The Zaporizhzhya nuclear power station in Ukraine has been without offsite power for more than a week and is relying on emergency diesel generators (EDGs) as it faces a possible blackout in 10 days, International Atomic Energy Agency (IAEA) director-general Rafael Grossi said at the weekend.
The EDGs are providing the electricity needed for essential nuclear safety and security functions, but concerns are growing about whether the site has sufficient diesel fuel available.
The plant, near the frontline of fighting in southeast Ukraine, lost connection to its only remaining offsite power line, the 330 kilovolt (kV) Ferosplavna-1 line, on 20 August following military activity on the northern side of the Dnipro River.
Since then, it has been operating several EDGs to supply the power required for its own needs, most importantly for pumps that cool all six reactors and their spent fuel pools.
In view of the extended loss of external electricity, the IAEA team at Zaporizhzhya has been closely monitoring the diesel fuel situation. On 24 August, the team visited most of the site’s 20 EDGs to check fuel levels in their tanks and to assess how long the available reserves could support the plant if offsite power is not restored.
On 28 August, Zaporizhzhya reported that it now has approximately 10 days of diesel fuel available on site for EDG operation, which is the minimum regulatory requirement.
The IAEA team was also informed that the most recent delivery of fuel to the plant’s offsite fuel farm took place almost half a year ago, in March. A further delivery, planned for May, has reportedly been delayed because of frequent military activity in the area.
The IAEA has not been able to visit this fuel storage since March 2025, with Zaporizhzhya citing security reasons.
However, on Thursday and Friday, the team observed the transfer of several dozens of tonnes of diesel fuel from two different offsite locations to the plant.
Availability Of Diesel Fuel ‘Of Paramount Importance’
Expressing concern about the diesel fuel situation, Grossi said the agency is closely monitoring the site’s ability to continue relying on EDGs for an extended period.
“The availability of diesel fuel is of paramount importance whenever a nuclear power plant loses offsite power, as is the ability to maintain uninterrupted logistical supply chains to and from the site,” Grossi said.
“The current situation once again shows why reliable external power and secure supply routes are indispensable for nuclear safety and security.
“Without the restoration of offsite power or additional diesel fuel deliveries in the near future, the plant could face a station blackout within approximately 10 days,” Grossi said.
All six units at Zaporizhzhya are shut down, but power is still needed to power essential safety systems, circulate water and continuously cool the radioactive fuel in the reactor cores and spent fuel pools to prevent a potentially catastrophic meltdown.
The Zaporizhzhya nuclear station fell under Russian military occupation in March 2022, days after the start of Russia’s invasion of Ukraine on 24 February 2022.
Both sides have blamed each other for military activity around Zaporizhzhya.
