Bulgaria’s Kozloduy nuclear power plant is reducing generation at both operating units as low Danube water levels widen a constraint that had previously affected only unit 5. The plant said the change extends the output curtailment to unit 6.
From October 8, generation at units 5 and 6 was being reduced by about 90 MW each, cutting combined output by approximately 180 MW. The reductions are precautionary operating measures intended to maintain safe and reliable reactor performance during prolonged low river flows.
Timeline of unit 5 curtailments
Unit 5 first cut production by around 120 MW on August 21. Output began recovering at the end of August, but deteriorating conditions prompted another reduction of about 60 MW on September 14.
During those earlier episodes, unit 6 continued operating normally while unit 5 was subject to the reductions. The later extension brings both units under the same operating constraint.
Coordination with authorities and grid operator
The extension to both units increases the potential impact on Bulgaria’s power balance. Kozloduy is coordinating its response with the Energy Ministry and transmission operator ESO, while forecasts of further river-level declines could require additional measures.
Energy Minister Iva Petrova said the plant prepared four technical options to reduce exposure to extreme low-water conditions. These include measures to support river levels near the site and greater use of alternative reservoirs.
Most of the options require medium-term implementation, leaving current production dependent on river conditions and operating limits.
