Two 80-meter barges deliberately sunk in the Danube to keep a nuclear power plant running. On Saturday, August 15, Hungary launched a controlled submersion operation near Paks, the country’s only nuclear facility, aimed at raising the river’s water level and ensuring a sufficient flow for reactor cooling. The first sign is encouraging: water levels at the plant’s pumping station have already risen by one centimeter.
The backdrop is a historic drought. The Paks plant is currently operating at just 25% of its 2,000-megawatt capacity, due to record-low water levels in the Danube, from which the facility draws its cooling water. Prime Minister Péter Magyar had warned that, without intervention, levels would drop to a critical threshold by Monday morning — at which point one of the last two operational turbogenerators would have had to be shut down. When the operation was launched, the Danube was reading -122 centimeters below the standard hydrometric reference level. The barges, positioned between Paks and Dunaszentbenedek, are being flooded through eight pumps in a gradual, reversible submersion procedure.
The sunken vessels act as a kind of low-head weir: they slow the current and raise the water surface around the plant’s cooling pumps. The expected effect is a local river level increase of up to 20 centimeters. This is a temporary measure, designed to buy time while a permanent structure is built on the riverbed. The government has begun placing 145,000 cubic meters of rock to create a “sill” — a submerged threshold running across the river’s main channel — which, according to official estimates, could raise the Danube by up to one meter near the plant. The HUN-REN energy research center has confirmed the technical feasibility of the project, while stressing that nuclear safety must remain the top priority and that the structure must account for river navigation, flood protection, and environmental impact.
The situation at Paks is not unique. Romania has already shut down its last active reactor — last Thursday, for the very same reason: Danube water levels too low for adequate cooling. Bucharest had attempted a similar move weeks earlier, sinking four rock-laden barges near the Cernavodă plant to redirect water toward its intake pumps. The intervention worked temporarily, but was not enough to withstand the prolonged heatwave. In Hungary, the stakes are higher given that Paks historically supplies around 40% of the country’s electricity — meaning any reduction in output has immediate consequences for households and industry alike.
Magyar described the current situation as something that “can no longer be considered an exceptional, isolated extreme event.” The summer of 2026 has made it clear that European nuclear plants built along major rivers must contend with an increasingly unpredictable water regime. Hungary’s response — sinking barges, building riverbed sills, mobilizing engineers and geologists within days — demonstrates strong political will to keep nuclear power online. The challenge now is to turn emergency fixes into lasting structural adaptations capable of safeguarding output through future summers as well.
