Recent Russian strikes have forced four out of nine of Ukraine’s functioning nuclear reactors to reduce output, according to the International Atomic Energy Agency (IAEA) on Thursday.
Moscow’s renewed strikes on Ukraine’s energy grid in recent months have forced rolling blackouts across the country, with electricity available for 12 hours or less per day for most users.
IAEA said in its Thursday briefing that the strikes have targeted energy facilities supporting the plants’ operations.
The strikes affected all three of Ukraine’s operational nuclear power plants (NPPs), according to the IAEA.
The briefing said the Khmelnytskyi and Rivne NPPs “had already lowered production of electricity as a result of military activities earlier this month,” with another recent strike further decreasing their output on Thursday after “they each lost the connection to one of their high-voltage power lines.”
IAEA representatives stationed at the plants also had to seek shelter during Thursday’s air raid, it added.
Another plant, the South Ukraine NPP, also lost connection to a high-voltage power line, with IAEA reporting “11 drones overnight one kilometer (0.6 miles) from the site.”
The IAEA did not specify the precise output from the reactors following the strikes.
The IAEA added that the connection to the Zaporizhzhia NPP, which remains under Russian occupation, was severed last Friday, but repair work has restored the link as of Thursday morning.
Ukraine’s precarious energy supply
Prior to Russia’s 2022 full-scale invasion, Ukraine had 56 gigawatt (GW) of installed capacity – sometimes called nameplate capacity – and 36 GW of actual capacity.
For context, a single GW is enough to power approximately 750,000 homes simultaneously in the US.
Before the attacks, nuclear power made up around a quarter of Ukraine’s nameplate capacity, while half of the total capacity came from thermal power plants – most of which had been battered by Russian strikes between 2024 and 2025, with the Russian campaign to hit thermal plants hitting its peak in the summer of 2024.
Russia has avoided direct strikes on nuclear power plants, likely out of fear of triggering a nuclear disaster and the ensuing international backlash. As a result, nuclear generation has remained the backbone of Ukraine’s shrinking power supply.
But recent attacks suggest Russia has begun targeting surrounding infrastructure to force reactors to reduce output.
Russia occupied the Zaporizhzhia NPP – the largest in Ukraine capable of generating close to 6 GW – at the onset of the 2022 invasion.
The remaining NPPs in Ukraine have a total capacity of 7.835 GW, according to another IAEA report – 2,835 GW from Rivne, 2 GW from Khmelnytskyi, and 3 GW from the South Ukraine NPP.