Krško Nuclear Plant May Reduce Output as Sava River Temperatures Rise

A prolonged heat wave has raised the temperature of the Sava River, lowering water flow and challenging the cooling system of Slovenia's Krško Nuclear Power Plant. The plant, which supplies about 15% of Croatia's electricity, operates under strict ecological limits: the average daily river temperature must stay below 28 °C and the rise may not exceed three degrees. Current measurements show the Sava at 24.6 °C with a 2.6 °C increase.

NEK, the plant operator, warned that if river conditions worsen it may have to cut reactor power or, in the worst case, shut down the facility within a week. Plant director Gorazd Pfajfer said the plant remains stable but acknowledged that higher water temperatures reduce efficiency and could force a partial power reduction. The plant uses cooling towers to supplement river water, but their operation increases electricity consumption and lowers overall output.

Experts offered mixed views. Tonči Tadić of the Ruđer Bošković Institute argued Krško is better positioned than other regional reactors because of its cooling‑tower system, while others highlighted the broader risk of heat‑related constraints on nuclear generation across the region.