Eskom has announced that Koeberg Unit 1 will return to service a month later than planned, now expected by the end of August.

The power utility has, however stressed that this does not increase the risk of loadshedding.

The delay in the return to service of Unit 1 is due to extra maintenance on its steam generators. Repairs were made after minor defects were found in four tubes, with international experts brought in.

Unit 2 remains fully operational, and Eskom says the winter electricity outlook remains unchanged.

Eskom says this revised timeline “underscores Eskom’s commitment to conducting thorough inspections and maintaining the highest quality standards to ensure the ongoing safe and reliable performance of South Africa’s only nuclear power station.”

In a statement, Eskom explains that the defects in the metal tubes were detected during a scheduled eddy current inspection — a non-destructive testing method used to detect
cracks, corrosion, or wear in the metal tubes of steam generators.

“Eskom immediately carried out an advanced automated process to address the four tube defects, supported by specialised international teams working alongside local experts. These critical repairs have now been completed to uphold the highest safety and quality standards.”

Importantly, the major maintenance activities, which included the legally required 10-year Integrated Leak Rate Test (ILRT), where the reactor building was pressurised over 72 hours and its leak rate and structural integrity were monitored, were completed.

Bheki Nxumalo, Eskom’s Group Executive, says the ILRT 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. 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 has emphasised that the revised return date for Koeberg Unit 1 will not increase the risk of loadshedding.

“The Winter Outlook released on 5 May 2025, which covers the period until 31 August 2025, remains valid. Importantly, the planned return of 2 500MW this winter does not rely on Unit 1.”

The outlook still shows that loadshedding will not be required if unplanned outages remain below 13,000MW. Even if outages rise to 15,000MW, loadshedding would be limited to a maximum of 21 days over the 153-day winter period, capped at Stage 2.