Eskom says that the main mechanical work on replacing the steam generators at Koeberg's Unit 1 has been completed and it will return to service on 3 November. 

Koeberg's Unit 2 will be taken offline on 7 November, slightly later than anticipated two weeks ago, avoiding the problem that both units would be offline simultaneously.

In a statement on Thursday, Eskom said: 

Unit 1 of the Koeberg Nuclear Power Station reached a significant milestone on Friday, 28 July 2023, when the mechanical work of the replacement of the steam generators was completed. This is the most significant part of the scope which involved complex activities and it means that Eskom is now proceeding with the outage activities that could not be performed in parallel with the replacement of the steam generators. Immediately after the completion of the outage activities, the reactor will be reloaded with fuel, enabling the return to service of the Unit.

The new steam generators will first be tested and synchronised to the grid. 

Each unit of Koeberg generates 900MW when the plant is operating optimally, equal to two load-shedding stages. There have been numerous delays to the project to replace the steam generators on Unit 1, fuelling concerns that both units would be offline simultaneously. Eskom says it has now mitigated that risk. 

Eskom hopes that replacing the steam generators will result in a 20-year extension of Koeberg's operating licence. The new steam generators are also more efficient than the old ones and will produce an additional 27MW.

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The replacement of the steam generators was first proposed in 2014. It has been held up by litigation and other issues.

Last year, an attempt to start the project in January had to be aborted after French contractors Framatome arrived to find that Eskom had not completed the containment building to store the radio-active old steam generators after removal. 

After the project restarted in January 2023, the timeline for the return of Unit 1 has shifted several times. 

Framatome has lodged hundreds of claims against Eskom for delays, while Eskom has issued counterclaims. As these will take a long time to resolve, Eskom does not have an accurate picture of the final costs of the projects. The lion's share of the contract was paid upfront to Framatome long before it actually commenced.  

While the risk of both units being offline simultaneously looks less likely to materialise now, Eskom announced recently that after the return of Unit 2 to generation, it will need to take Unit 1 out again for a 200-day outage. This is to test and repair, if necessary, the containment buildings of the reactor, following exposure to weather and seawater. The same is likely to be required for Unit 2. 

This means SA will continue to operate with only one unit at a time, well into 2025.