Power Grid

The planned return of Koeberg Nuclear Power Station’s Unit 1 has been delayed by one month, shifting its expected restart from July to the end of August 2025. This delay follows routine safety checks that uncovered defects in four metal tubes within the plant’s newly installed steam generators.

The discovery was made during eddy current testing, a standard inspection technique used to identify weaknesses in critical components. Eskom responded swiftly by deploying both local and international experts to carry out automated repairs on the faulty tubes, ensuring that all components meet required structural and safety standards.

Despite this setback, Eskom has assured the public that the delay will not affect the national electricity supply. According to the utility’s winter outlook released in May 2025, loadshedding would only be triggered if unplanned outages exceeded 13,000 megawatts. So far, outages remain well below that threshold.

Only 26 hours of loadshedding have occurred since the start of the financial year. Additionally, Koeberg’s Unit 2 continues to operate at full capacity, contributing approximately 946 MW with an energy availability factor nearing 100%, helping to maintain the stability of the national grid.

This delay forms part of Koeberg's larger Long-Term Operation (LTO) programme, which is aimed at extending the life of the plant and improving its long-term reliability. The extensive work on Unit 1 includes refuelling, steam generator replacement, and a series of compliance tests with grid requirements.

Notably, the unit successfully completed a full-load rejection test in December 2023. Unit 1 had already experienced a lengthy outage from December 2022 to November 2023, and the current extension reflects Eskom’s commitment to thorough inspection and high safety standards.

Eskom has reiterated that safety remains its highest priority throughout the refurbishment process. By choosing to delay the unit’s return, the utility is ensuring that all systems are fully verified and operating according to international nuclear safety protocols. Though the delay is unfortunate, the repairs and inspections are essential for guaranteeing the plant’s safe operation for years to come.

With Unit 2 running steadily and Unit 1 expected back online by the end of August, Eskom remains confident in its ability to meet electricity demand without compromising safety.