Hungary’s 2,000 MW Paks nuclear power plant could be forced to stop electricity generation after record-low levels on the Danube threatened the operation of its cooling-water intake system. The plant normally supplies about half of Hungary’s electricity and is described as the core of the country’s baseload generation. A complete shutdown would create an immediate need for higher imports and thermal replacement during a period of elevated summer demand.
Cooling intake access under approaching Danube low-water levels
Operators say the Danube still contains sufficient water for cooling, but the river is nearing a level at which intake pumps may no longer be able to draw water into the plant. In response, operators have started lowering the intake structures to maintain access.
Reported water levels are 28 centimetres below the previous record low measured in 2018. They are also more than one metre below the minimum level used when the plant was designed more than four decades ago. The scale of the deviation is described as indicating an operating risk rather than a typical seasonal fluctuation.
Causes cited for declining river conditions
The plant attributes the decline to long-term riverbed erosion, upstream sediment retention, and historical dredging. It also points to increasingly frequent climate extremes. The absence of significant spring flooding in 2026 left the river unusually low before the summer demand period began.
Paks uses four alert levels for low-water conditions. It is currently operating under Level 3, while Level 4 requires all reactors to shut down. Management indicated that Level 4 could be reached within 24 to 72 hours, depending on river conditions.
Cooling-water demand shift and safety operations during shutdown
If reactors shut down, cooling-water demand would fall sharply. Normal generation requires approximately 100 cubic metres per second, while maintaining safe cooling after shutdown needs around 5 cubic metres per minute. The operator has stressed that reactor safety can be maintained for an extended period even if low-water conditions persist.
Regional power flows and forward price impacts
Market effects would begin immediately if output declines. Reduced Paks generation has already pushed Hungary toward heavier imports from Austria, Slovakia and Romania. A full shutdown would tighten supply in Romania, Bulgaria, Slovenia, Croatia and Serbia as cross-border capacity is redirected toward Hungary’s deficit.
The risk has also affected forward pricing. Hungarian week-ahead power has developed an exceptional premium over Germany and Italy, reflecting the possibility that the nuclear constraint could persist into early August.
The physical problem may ease within days if river levels recover, allowing reactors to return to service. The underlying issue remains that an asset supplying roughly half of Hungary’s electricity is operating with a cooling-water system designed for Danube conditions that no longer provide a reliable lower boundary.
