Koeberg Nuclear Power Station in the Western Cape. Eskom says Unit 1 was safely taken offline after a turbine trip, with nuclear safety unaffected and the grid remaining stable
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Power utility Eskom has taken Koeberg Nuclear Power Station’s Unit 1 offline after a turbine trip in the early hours of Thursday.
The utility said that the unit was safely taken offline shortly before 1am and that operating conditions remained stable throughout the incident.
Eskom said nuclear safety was not compromised and there was no risk to employees, the public or the environment.
The utility added that Koeberg’s protection and monitoring systems functioned as designed, ensuring the unit remained safe during the incident.
"The removal of Unit 1’s capacity from the grid poses no risk to the national electricity supply. Eskom has sufficient generation capacity available, and the grid remains stable and secure," Eskom said.
"Koeberg’s Unit 1 was last taken offline for major maintenance, completed in October 2025. Since then, the unit has operated reliably, with generation temporarily reduced in August 2026 as a precautionary measure due to seawater intake challenges linked to a sardine influx near the station’s cooling water system."
Earlier this week, Eskom reduced Unit 1’s generation to 50% after a cooling pump automatically switched off following a buildup of marine material in the seawater intake area.
The utility later increased generation to 70% after the marine material was cleared and the cooling system was restored.
"Eskom has safely increased generation at Koeberg Unit 1 to 70%, after previously reducing output to 50% as a routine safety precaution. This controlled adjustment followed the automatic shutdown of a cooling pump due to a buildup of marine material in the seawater intake area," Eskom said on Thursday.
The earlier disruption came as large numbers of sardines were reported along parts of the Western and Southwestern Cape coast, with increased sardine mortality remaining under inter-agency investigation.
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