Why a Drying River Forced Romania to Turn Off Its Nuclear Power

On 13 August 2026, Romania started shutting down the last working reactor at its only nuclear power plant. The reason was surprisingly simple: the river that cools the reactor was running out of water. A severe drought had pushed the Danube river to record-low levels, leaving the plant without enough water to safely operate. The plant's first reactor had already shut down in late July for the same reason. The company that runs the plant, Nuclearelectrica, said it did not expect to restart either reactor within the next ten days The Guardian.

Nuclear power plants work a lot like a pot of boiling water on a stove. The reactor generates intense heat, and water is used to carry that heat away and keep everything from overheating. Without enough cool water flowing through, the plant cannot safely run. Romania's Cernavoda plant sits on the Danube, and both of its reactors — which together supplied about 20% of the country's electricity — now need that river water and cannot get it.

To make up for the lost power, Romania turned on a 330-megawatt coal plant and increased its use of wind and hydro power. The government declared an energy emergency for August and asked businesses and households to cut back on electricity use during the busiest hours. Large factories may face restrictions in the evenings. In early August, the government ordered two major car manufacturers, Dacia and Ford, to pause their production in Romania until 19 August.

Romania had tried to buy time before shutting down completely. Earlier in August, authorities blasted a rock formation to redirect Danube water toward the plant's cooling system. That fix was expected to keep the last reactor running for about nine days Reuters. That time has now run out.

The problem reaches beyond Romania. Moldova, a neighboring country, depends on Romanian electricity imports to cover up to 60% of its power shortages. With those imports cut off, Moldova must either buy more expensive electricity from Ukraine or western Europe, or impose rolling blackouts — planned power cuts that rotate through different areas. Moldovan energy expert Sergiu Tofilat told Radio Chisinau that the country should prepare for things to get worse, including power outages.

The Danube is Europe's second-longest river, stretching about 2,850 kilometers from western Germany to the Black Sea. According to the Copernicus European climate change observatory, nearly two-thirds of the river has seen water levels drop to their lowest point for July in 34 years. The Danube cools several nuclear plants along its path, not just Romania's.

Hungary came close to shutting down its only nuclear plant, called Paks, which also uses Danube water for cooling. Paks normally supplies about a third of Hungary's electricity and has been partially shut down since late July. On 12 August, Prime Minister Péter Magyar ordered the construction of an underwater barrier to help control water flow near the plant. Two large barges, each 80 meters long, are being positioned at Paks and could be deliberately sunk to raise the water level if conditions get worse.

France is dealing with a similar crisis. More than 20% of the country's nuclear power capacity was offline during the week of 14 August, according to calculations by the AFP news agency using data from EDF, France's main nuclear operator. The outages were linked to drought, extreme heat, and even a swarm of jellyfish that blocked cooling-water intakes. Thirteen of France's 57 nuclear reactors were affected.

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

The broader picture here is that Europe's nuclear plants were built decades ago, when rivers like the Danube had more reliable water flows. Those assumptions no longer hold. For Moldova, the danger is acute because it relies heavily on a single power supplier that can no longer export. For Romania, shutting down production at Dacia and Ford — both major employers — will bring mounting economic costs the longer the reactors stay offline. And for energy planners across Europe, the combination of drying rivers, extreme heat, and even jellyfish blocking pipes raises serious questions about whether nuclear power can remain reliable as the climate warms.