Drought Shuts Down Romania's Nuclear Power Plant — and Europe's River-Cooled Reactors Are at Risk

On 13 August 2026, Romania's state-owned nuclear operator Nuclearelectrica began shutting down the last working reactor at its Cernavoda nuclear power plant. The cause was not a mechanical failure or a safety lapse but something more elemental: drought had pushed Danube river water levels to record lows, cutting off the cooling supply the reactor needs to operate. The shutdown takes the plant's sole remaining unit offline, following the closure of its first reactor in late July for the same reason. Nuclearelectrica said it did not expect a restart within the next ten days The Guardian.

The two 706-megawatt reactors at Cernavoda — known as CANDU pressurized heavy water reactors, a Canadian design that uses heavy water (water with a heavier hydrogen isotope) to slow neutrons and transfer heat — together supplied about 20% of Romania's electricity. With both now offline, the country has turned to a 330-megawatt lignite (a low-grade coal) plant and increased wind and hydro generation to fill the gap. The government declared a state of energy emergency for the month of August and asked businesses and households to reduce consumption during peak hours. As a last resort, large industrial users face evening restrictions. In early August, the government went further, ordering carmakers Dacia and Ford to halt production in Romania until 19 August.

Romania had tried interim measures before resorting to a full shutdown. In early August, authorities blasted a rock outcrop to redirect Danube water toward the plant's cooling intake — a stopgap that Nuclearelectrica said could keep the remaining reactor running for nine days Reuters. That window has now closed.

The effects reach beyond Romania. Moldova, a smaller neighboring country, relies on Romanian power imports to cover up to 60% of its electricity shortfall. With those imports cut off, Moldova must either buy more expensive power from Ukraine or western European suppliers, or impose rolling blackouts — planned, temporary power cuts that rotate through neighborhoods. Moldovan energy expert Sergiu Tofilat told Radio Chisinau that the country should brace for a worsening situation, including outages.

The crisis extends along the Danube itself. Nearly two-thirds of Europe's second-longest river — roughly 2,850 kilometers from western Germany to the Black Sea — has seen flow rates drop to the lowest July levels on record in 34 years, according to the Copernicus European climate change observatory. The Danube serves as a cooling source for multiple nuclear facilities along its course.

Hungary came close to a full shutdown at its only nuclear plant, Paks, whose four Danube-cooled reactors typically supply about a third of the country's electricity. Paks has been partially shut down since late July. On 12 August, Prime Minister Péter Magyar ordered the construction of a submerged weir (a low dam built underwater to control river flow) near the plant. Two 80-meter barges are being positioned at Paks and could be deliberately sunk to raise the water level if conditions worsen.

France faces a parallel crisis. More than 20% of EDF's total nuclear production capacity was offline in the week of 14 August, a figure AFP calculated from EDF data and attributed to outages linked to drought, extreme heat, and even a jellyfish invasion that clogged cooling-water intakes. Thirteen of the 57 reactors in France's fleet were affected.

The World Weather Attribution group of scientists has linked the European drought to human-induced climate change.

The broader context here is that the simultaneous loss of nuclear capacity across Danube-dependent and heat-affected facilities exposes a structural weakness in Europe's power system. River-cooled reactors were designed and sited based on historical river-flow data that no longer reflects reality. For Moldova, the immediate stakes are sharpened by its heavy dependence on a single supplier now unable to export. For Romania, the production halts at Dacia and Ford — both major employers — carry economic costs that will grow the longer both reactors stay offline. And for European energy planners, the convergence of low river flows, extreme heat, and biological interference at cooling intakes across France and the Danube basin raises hard questions about how resilient nuclear generation can be in a warming climate.