Eskom today announced a revised timeline for the planned maintenance of Unit 1 at the Koeberg Nuclear Power Station, with its return to service now anticipated by the end of August 2025. The unit, currently offline for the second phase of its long-term operation maintenance programme, was originally scheduled to be back online by July 2025. This adjustment, Eskom stated, underscores its commitment to comprehensive inspections and upholding the highest quality standards.
The delay stems from critical findings during scheduled detailed eddy current inspections. This specific non-destructive testing (NDT) method, designed for detecting cracks, corrosion, or wear in metal tubes, identified defects on four tubes across two of the newly installed generators.
"Eskom immediately carried out an advanced automated process to address the four tube defects, supported by specialised international teams working alongside local experts," the power utility clarified. "These critical repairs have now been successfully completed to uphold the highest safety and quality standards."
Crucially, major maintenance activities, including the legally mandated 10-year Integrated Leak Rate Test (ILRT), have already been concluded. The ILRT, which involved pressurizing the reactor building over 72 hours to monitor its leak rate and structural integrity, confirmed the robustness and leak-tightness of Unit 1’s containment structure, further reinforcing its safety in line with international standards.
"Our top priority is always the safety of our employees, the public and the environment," affirmed Bheki Nxumalo, Eskom Group Executive for Generation. "Carrying out these additional inspections and repairs to world-class standards, we are investing in the long-term reliability of Koeberg and South Africa’s energy future." Nxumalo added that the ongoing maintenance on Unit 1 is set to deliver decades of affordable, low-carbon baseload power, demonstrating how nuclear energy supports both economic growth and environmental sustainability. "Through our commitment to high-quality maintenance and the expertise of the Koeberg team demonstrating exceptional skills, we are ensuring nuclear power remains a vital part of the country’s energy mix."
Eskom has assured the public that the revised return date for Koeberg Unit 1 will not escalate the risk of load-shedding. The Winter Outlook, released on May 5, 2025, which covers the period until August 31, 2025, remains valid. The planned return of 2,500MW this winter does not rely on Unit 1's immediate availability. Eskom's outlook indicates that load-shedding will not be required if unplanned outages remain below 13,000MW. Even if outages reach 15,000MW, load-shedding would be limited to a maximum of 21 days over the 153-day winter period, capped at Stage 2. No load-shedding has been implemented since May 15, 2025, with only 26 hours recorded for the financial year-to-date since April 1.
Once all maintenance work is complete, Unit 1’s reactor core will be refuelled, tested, and synchronized to the national grid. Eskom highlighted its strategic approach of staggering planned outages at Koeberg every 16 to 18 months, ensuring both units are never offline simultaneously. Together, Koeberg Units 1 and 2 contribute approximately 1,860MW, accounting for about 5% of the country’s electricity needs. Unit 2 continues to operate at full capacity, generating up to 946MW, with a year-to-date Energy Availability Factor (EAF) of 99.38% as of the end of June 2025, contributing to a stable national power system with a month-to-date EAF of 62%.
Reference: https://mybroadband.co.za/news/energy/602604-bad-news-about-koeberg-nuclear-power-station.html
