Eskom has announced a revised return date for Koeberg Unit 1, pushing its re-entry into the grid to the end of August 2025. This delay follows an extended maintenance outage that began earlier in the year as part of the unit’s long-term operation programme a key condition of its 20-year life extension granted by the National Nuclear Regulator (NNR) in 2023.
The outage was originally planned to last 150 days, with the unit scheduled to return by July. However, inspections using eddy current testing a non-destructive method for detecting flaws in steam generator tubes revealed defects in four tubes across two newly installed steam generators.
Repairs Completed with International Support
Eskom responded swiftly to the discovery, implementing an advanced automated process to repair the affected tubes. The repairs were carried out with the help of international experts working alongside local teams. The utility confirmed that these repairs were now complete and met the highest safety and quality benchmarks.
In addition to the tube repairs, Eskom successfully concluded the Integrated Leak Rate Test a legally mandated procedure conducted every ten years. The test involved pressurizing the reactor building over a 72-hour period to monitor for leaks and structural integrity. According to Eskom, the results confirmed that Unit 1’s containment structure remains robust and leak-tight, aligning with international safety standards.
Unit 2 Stable as Winter Outlook Holds
Despite the delay, Eskom insists the risk of loadshedding this winter remains unchanged. The utility emphasized that Koeberg Unit 2 continues to operate reliably, delivering up to 946 MW with an energy availability factor of 99.38% as of June 2025.
Other Units Boost Supply but Diesel Use Increases
Eskom has also highlighted progress elsewhere. Kusile Unit 6 was synchronized to the grid in March, adding 800 MW. Medupi Unit 4 returned on July 6 after being offline in 2021.To compensate for gaps, however, Eskom has significantly increased its use of diesel-powered open cycle gas turbines and Still remains confident that “The national power system is stable,” it stated.
