Prolonged drought and unusually low levels of the Danube have led to severe pressure on nuclear energy in Central and Southeastern Europe. In Romania and Hungary, nuclear power plants that use the river for cooling have limited or ceased production to comply with safety requirements.
"Paks" NPP was shut down for the first time in 44 years
The Hungarian "Paks" NPP – the only nuclear power plant in the country – was completely shut down on Sunday for the first time in its 44-year history. The reason is the drop of the Danube to record-low levels, which hindered the supply of sufficient water to the cooling systems.
Before the full shutdown, the plant's production had shrunk to just 240 megawatts, down from a normal capacity of around 2000 megawatts. One of the units had been taken out of operation earlier, and the rest were gradually shut down as the river level approached the critical threshold.
"Paks" NPP has four reactor units and, during normal operation, provides approximately one-third of Hungary's electricity. Data on the plant's share vary according to seasonal consumption and the load of other production capacities.
Hungarian authorities have taken emergency engineering measures to preserve the water inflow to the pumping systems. These include the construction of an underwater barrier near the plant and the management of sluices along the river. Later, rainfall in the Austrian part of the catchment area led to a gradual rise in the level, which allowed one turbine to be restarted.
Prime Minister Péter Magyar announced that the Danube level had risen by nine centimeters above the lowest point recorded on Sunday. He warned that returning already shut-down units to operation takes time, even when the water risk begins to recede.
Both units of "Cernavodă" are shut down
Romania also suspended the operation of its only nuclear power plant, "Cernavodă". The first of the two reactors with a capacity of 706 megawatts each was shut down at the end of July, and on August 13, the operator Nuclearelectrica began a controlled shutdown of the second unit as well.
The plant, located on the Danube, usually provides about one-fifth of Romania's electricity. According to the operator, the safe shutdown and maintenance of both units in that state do not affect nuclear safety parameters, nor do they create a risk for staff, the population, or the environment.
The plant director, Romeo Urjan, stated that he does not expect operations to resume "in the next 10 days". This is the first time since 2003 that drought has forced "Cernavodă" to completely cease production.
Before the final shutdown, the Romanian military carried out blasting operations on rock formations in one of the Danube's branches to assist the water inflow to the plant. The measure failed to prevent the shutdown of the second reactor.
Heatwaves burden European energy sector
The cases in Hungary and Romania demonstrate the vulnerability of energy infrastructure to a combination of hot weather, drought, and low river levels. Such conditions simultaneously increase the demand for electricity for cooling and limit production from plants that rely on water for cooling or from hydroelectric capacities.
On July 12, 2026, up to 29 gigawatts of French nuclear capacity, or 43% of the country's total nuclear capacity, were unavailable. The Ember analysis clarifies that at least 11 gigawatts of this capacity were reported as forced outages or restricted for environmental reasons, while 18 gigawatts were cited as planned maintenance and other factors.
This means that the effect of the heatwave on the French nuclear system cannot be completely separated from planned interruptions. Nevertheless, the data show how sensitive the power system remains to extreme weather conditions.
The Danube passes through or forms the borders of 10 countries. Record-low waters are already hindering shipping, tourism, and industrial activities along the entire length of the river, with the consequences of the drought extending far beyond the energy sector.