Romania shuts down sole nuclear plant as record-low Danube cuts cooling water

Cernavoda goes dark

Romania's state-owned nuclear producer Nuclearelectrica began the process of disconnecting Unit 2 at its Cernavoda plant on 13 August, as Danube river levels fell to a record low. The plant's two 706-megawatt reactors, which normally supply about a fifth of Romania's electricity, had already lost Unit 1 in late July when drought first curtailed the cooling water supply. The shutdown of Unit 2 marks the first complete halt at Cernavoda since the 2003 drought, when only one reactor was operating and the plant stopped for several weeks. According to local media cited by AGI, the full shutdown of the reactor was expected between 11:00 and noon local time on 13 August. The energy ministry said in a statement that Unit 2 would be shut down in a controlled manner given the current hydrological conditions. Authorities have not indicated a date for resuming operations.

Emergency measures

Romania declared a state of energy emergency throughout August and asked companies and households to voluntarily reduce consumption during peak evening hours. The energy ministry activated a 330-megawatt lignite-fired power plant and is relying on increased wind generation and hydropower from available reservoir water to offset the shortfall. The ministry stated that the national grid has cross-border capacity of roughly 4,000 megawatts for electricity imports, and that European operators are coordinating to ensure supply safety across grids affected by weather conditions. The government has prepared a system of staged, pre-notified power cuts for industrial consumers if needed. Slightly cooler temperatures were expected to lower peak evening demand.

Efforts to buy time

Before resorting to the shutdown, Romania had taken a series of physical interventions to keep the reactor running. Engineers dredged the riverbed, detonated a rock obstruction, and sank four rock-filled barges in the Danube to redirect water flows toward the plant, according to Il Fatto Quotidiano. These efforts, with estimated costs exceeding 2 million euros, succeeded only in delaying the shutdown. Unit 1 had already been stopped in late July; the dredging and barge operations allowed Unit 2 to continue operating briefly longer before river flows dropped further. The Danube, Europe's second-longest river after the Volga and the longest navigable river in the EU, has seen its flow fall to a record minimum amid repeated heatwaves and a lack of rainfall across the continent.

Regional spread

The Danube drought is affecting nuclear plants across Europe. In Hungary, the Paks plant, whose four reactors normally cover about a third of the country's electricity needs, has been partially stopped since late July. Prime Minister Peter Magyar announced on 13 August that the government has ordered construction of a submerged dam near Paks, with two 80-metre barges positioned at the site that could be sunk to raise water levels. Hungary has so far avoided a full shutdown at Paks.

In Switzerland, operator Axpo shut down the Beznau nuclear plant on 26 June to prevent the Aar river, used for cooling, from overheating. Environmental regulations set temperature limits on cooling water discharges to protect aquatic ecosystems; when upstream water temperatures rise too high, operators must reduce output or halt reactors. In France, the Nuclear Safety Authority (ASNR) granted a temporary waiver adjusting discharge limits for the Rhône, and the country shut down 8 of its 57 nuclear reactors, according to AGI.