The final pair of working reactors at the Zaporizhzhia nuclear plant were briefly cut off from Ukraine's power grid on Thursday, Kyiv officials say.
This satellite image courtesy shows the Zaporizhzhia nuclear power plant, situated in the Russian-controlled area of Enerhodar, eastern Ukraine. Photo: AFP PHOTO / Satellite image ©2022 Maxar Technologies
Ukraine's nuclear agency said the problem was caused by nearby fires that damaged overhead electricity lines.
It comes amid claims from Kyiv that Russia is trying to divert power from the occupied plant to its own grid.
There is also growing concern over fighting near the complex, which is the largest nuclear plant in Europe.
The fires, at a nearby coal power plant, interfered with the power lines, temporarily cutting Zaporizhzhia off from the national grid for the first time in its history, Ukraine's state nuclear agency said on Thursday.
"As a result, the station's two working power units were disconnected from the network," it said.
The International Atomic Energy Agency (IAEA) warned that having "a secure off-site power supply from the grid is essential for ensuring nuclear safety".
It coincided with media reports of power outages across neighbouring Russian-occupied towns and villages, amid accusations from Ukraine that Russia could be intentionally trying to disconnect the Zaporizhzhia plant from the Ukrainian grid in order to reconnect it to the Russian one instead.
Washington officials condemned any bid by Moscow to redirect the power generated by the Zaporizhzhia plant away from Kyiv's national grid.
"The electricity that it produces rightly belongs to Ukraine," US State Department spokesperson Vedant Patel said on Thursday evening, adding that "no country should turn a nuclear power plant into an active war zone."
Satellite images taken on Wednesday showed an extensive fire burning in the immediate vicinity of the nuclear complex.
Ukraine's President Volodymyr Zelensky blamed the damage on Russian shelling, and in his nightly address accused Moscow of putting Ukraine and Europe "one step away" from disaster.
But local Russian-appointed governor Yevgeny Balitsky blamed the Ukrainian military for the strikes, accusing them of causing power outages to the region as a result.
The BBC was not able to independently verify who was responsible.
Radiation levels nearby remained normal despite the Zaporizhzhia nuclear complex losing its main power supply on Thursday, local officials reported.
The plant "remained connected to a 330kV line from the nearby thermal power facility that can provide back-up electricity if needed," the IAEA said in a statement, citing Ukraine's state nuclear agency.
It added that all six nuclear reactor units remained disconnected from the power grid despite the line having been restored later on Thursday.
Normally the nuclear plant supplies one-fifth of Ukraine's total electricity - so its continued disconnection from the national grid would pose serious challenges for Ukraine.
The nuclear site has been occupied by Russian military forces since early March but continues to be operated by Ukrainian nuclear technicians.
The Kremlin has signalled it will allow international inspectors to visit the complex - but until that happens it is difficult to verify what is happening on the ground.
"Almost every day there is a new incident at or near the Zaporizhzhia nuclear power plant. We can't afford to lose any more time," IAEA director general Rafael Grossi said in a statement, repeating his call to lead an international mission to the plant in the next few days.
"If the diesel generators hadn't turned on, if the automation and our staff of the plant had not reacted after the blackout, then we would already be forced to overcome the consequences of the radiation accident," President Zelensky warned on Thursday night.
Local media is reporting that nearby towns lost electricity supplies after Russian officials switched off power to many parts of the occupied Zaporizhzhia region.
The mayor of Enerhodar, which is located next to the nuclear plant, claimed on Thursday that the city had no power or water at all.
There were also reports of power cuts in the Russian-occupied cities of Melitopol and Kherson.
- BBC