Romania's Cernavodă nuclear plant prepares to shut down last reactor as Danube hits record low

Cernavodă Unit 2 faces controlled shutdown

Romania's nuclear power plant at Cernavodă is preparing to shut down its second and last operating reactor as the Danube falls to its lowest recorded levels. Nuclearelectrica announced on August 11 that Unit 2 could be taken offline on the morning of August 13, depending on river level forecasts from INHGA. Unit 1 was already shut down in a controlled procedure beginning July 27, after the Danube's flow dropped below levels needed to supply cooling water safely.

Sorin Rîndașu, deputy general director of Apele Române, told Digi24 that the river reached minus 230 centimetres at Cernavodă, a threshold triggering shutdown procedures. Levels fell approximately six centimetres in the hours before his statement, with the Danube's flow at Porțile de Fier II measured at about 1,375 cubic metres per second.

It is inevitable, according to all the data we have.

Rîndașu confirmed the readings represent an all-time low, stating he had never encountered such values or such low flows. He estimated Unit 2 could remain stopped for at least two weeks.

Flow projections and force majeure

The flow reaching the plant area is projected to worsen. The Bala branch measured 300 to 305 cubic metres per second on Monday, but could drop toward 280 cubic metres per second. Only part of that flow reaches the plant; if the value falls below 45 cubic metres per second, the plant cannot operate. Ana-Maria Agiu, spokesperson for Apele Române, said dredging work is expected to reach the Izvoarele area on August 16 or 17, which would cause a further drop of nearly 10 centimetres at Cernavodă, from minus 229 to approximately minus 336 centimetres.

Nuclearelectrica informed the Bucharest Stock Exchange on August 11 that the Constanța Chamber of Commerce issued force majeure opinions on August 10, applicable to electricity delivery contracts. The company stated the severe hydrological drought has made it impossible to fully meet contractual obligations from its own production since July 27.

Compensation measures

The Energy Ministry and the National Energy Dispatcher prepared a plan to cover the lost capacity. Measures include electricity imports from regional and European systems, reactivation of the Rovinari 4 coal unit at Complexul Energetic Oltenia from reserve, and increased production by Hidroelectrica within available water resource limits. The ministry appealed to households, public institutions, and businesses for responsible consumption, especially between 19:00 and 23:00. As a last resort, consumption could be limited for large industrial consumers in that window, though household consumers are not targeted.

Bulgarian Kozlodui plant at risk

The low Danube also threatens Bulgaria's Kozlodui nuclear plant, which relies on the river for cooling. Nuclear energy expert Georgi Kaschiev, former chairman of the Kozlodui board, warned that a further drop of 20 centimetres would force the plant's suspension. The river at the plant's pumping station stood at approximately 20.62 metres above sea level. Kaschiev said forecasts indicate a slight further decline, but the first minimum operating limit should not be reached in the next two to three weeks.

Navigation on the Bulgarian section remains restricted, with channel depths as low as 1.5 metres in critical areas including Belene Island, Svishtov, and Somovit. One ship remained stuck near Lom in the 24 hours before reporting, though authorities said it did not block traffic. Danube water temperatures at five main hydrometeorological stations ranged between 26.4 and 27.3 degrees Celsius.