Heat and drought are curbing nuclear output along the Danube.
Why it matters: Cooling-water limits are hitting power plants as Europe heats up, reducing output when demand can stay high. That can affect electricity prices, grid stability and energy security across the region.
- Romania's Cernavoda plant shut one reactor after record-low Danube levels tied to extreme heat and low rainfall.
- AP said Romania sank four rock-laden barges in the Danube to help redirect water toward Cernavoda.
- Hungary's Paks plant was at risk of a full shutdown within 72 hours because of persistently low Danube levels.
- EDF said Blayais and Chooz in France could reduce reactor output because of high temperatures and thermal-discharge limits.
Europe's late-summer heat and drought are forcing nuclear operators to adjust output as rivers run low and water temperatures rise.
In Romania, one of the two reactors at the Cernavoda nuclear plant was shut down after record-low Danube levels linked to extreme heat and low rainfall, according to AP. Romania also sank four rock-laden barges into the river to help redirect water toward the plant. The IAEA's Romania profile says Cernavoda has two units and that nuclear power supplied roughly one-fifth of Romania's electricity at the end of 2024.
Hungary has faced the same pressure on the Danube. AP reported that the Paks plant was at risk of a full shutdown within 72 hours because of persistently low river levels, while World Nuclear News said the river's record lows had already pushed both Paks and Cernavoda toward operational changes.
France's EDF has also flagged heat-related constraints. On July 7, EDF said the Blayais plant could adapt reactor output because elevated Gironde temperatures had to remain within thermal-discharge limits. On June 26, EDF said output at Chooz could be reduced because of high temperatures. Those notices show that the river-heat constraint is not limited to the Danube, even if the immediate pressure is clearest in Romania and Hungary. EDF on Blayais and EDF on Chooz.
By the numbers
- 2 - Reactor units at Romania's Cernavoda plant, according to the IAEA.
- 1/5 - Roughly the share of Romania's electricity supplied by nuclear power at the end of 2024, according to the IAEA.
- 72 hours - The window AP said Hungary's Paks plant faced before a possible full shutdown.
Yes, but: EDF's generation outlook is a medium-term estimate, so it should not be read as a direct read-through to the current heatwave.