Elevated air and water temperatures and reduced river discharge rates across Europe have constrained cooling capacity at several nuclear facilities, forcing power curtailments and operational halts.
In France, rising river temperatures led EDF to shut down or reduce output at multiple reactors (including units at Chooz, Cattenom, Golfech, Bugey, Saint-Alban and Tricastin) this early August to comply with statutory thermal discharge limits, pushing fleet unavailability close to 20%. Additionally, biological clogging of seawater intake structures by jellyfish blooms temporarily disrupted operations at the Gravelines facility.
In Southeast Europe, Slovenia’s Krško plant lowered reactor output to 80% to adhere to environmental compliance parameters limiting the Sava River mixing temperature to 28°C and capping daily thermal delta increases at 3°C. Decreased flow rates along the Danube similarly required operational cutbacks at Cernavodă in Romania, Paks in Hungary, and Kozloduy in Bulgaria.