Electricity output from Slovenia’s Krško Nuclear Power Plant (NEK) has slightly declined in recent weeks due to environmental and operational constraints linked to low water levels in the Sava River.
Under normal operating conditions, the plant delivers more than 700 MW of electricity to the transmission network. However, data from Slovenian transmission system operator ELES shows that recent output at the grid connection point has decreased to around 690 MW.
According to the plant operator, the reactor itself continues to operate at full 100% capacity, and the reduction in exported electricity is not related to any nuclear or mechanical fault. Instead, the lower output is primarily driven by increased internal electricity consumption and reduced efficiency in the secondary cooling system.
The situation is closely connected to reduced water flow in the Sava River, which has been affected by limited rainfall. The plant uses river water in its tertiary cooling circuit to dissipate excess heat generated during electricity production. Water is pumped through the condenser system, absorbs heat from steam, and is then returned to the river.
Environmental regulations require strict thermal limits. The average daily temperature of the Sava at a designated monitoring point downstream from the Brežice hydropower plant must not exceed 28°C, while the temperature increase caused by the plant must remain below an average of 3°C.
When river conditions approach these limits, the plant progressively activates cooling towers to reduce thermal discharge into the river. If those measures are not sufficient, the facility must also reduce the amount of electricity delivered to the grid.
Plant officials emphasized that the current reduction in output is therefore the result of environmental compliance and cooling system adjustments, rather than any technical issues with the reactor itself.
