Eskom has confirmed that Koeberg Unit 1 will return to service by the end of August – later than the previously projected July timeline. The delay follows the identification and repair of defective tubes during steam generator inspections.
Unit 1 has been offline since December 10, 2023 for long-term operation (LTO) maintenance. During scheduled eddy current testing of the steam generators, four defective tubes were found across two of the recently installed units. Eskom said the repairs were completed using automated processes involving international and local teams.
Structural integrity tests, including the 10-year integrated leak rate test (ILRT), were completed during the outage. The ILRT involved pressurising the reactor building for 72 hours to assess containment leak rates. Eskom said the results met international nuclear safety requirements.
“All inspections and repairs contribute to the long-term reliability of Koeberg and support the future operation of the plant,” said Bheki Nxumalo, Eskom’s Group Executive for Generation.
Unit 1 will be refuelled, tested and synchronised to the grid once all maintenance work is finalised. Koeberg’s LTO schedule ensures only one unit is offline at a time. Unit 2 remains in operation with an energy availability factor of 99,38% as of the end of June 2025.
Eskom said the revised return-to-service date for Unit 1 does not affect the 2025 Winter Outlook, which is in effect until August 31. The outlook assumes that Koeberg Unit 1 remains offline and forecasts no load shedding if unplanned outages remain below 13 000 MW.
