Nuclear power problems in South Africa

Electricity and Energy Minister Kgosientsho Ramokgopa has raised concerns over “shortcomings” in extending Koeberg Unit 2’s life and Eskom’s repairs at Medupi Power, potentially putting nearly 2,000MW of generating capacity at risk.

According to energy expert Chris Yelland, Eskom has delayed the return of Koeberg unit 2 from June 2024 to December 2024, while Medupi’s unit 4 generator repairs will now only be completed in March 2025.

“Until the above are successfully completed, Eskom is reluctant to say that load-shedding is finally over in SA,” said Yelland.

During a briefing updating the media on the Energy Action Plan’s implementation, Ramokgopa said the state-owned power utility has faced delays in returning Koeberg’s Unit 2 generator to service.

It contributes roughly 940MW to the national power grid.

The unit is currently undergoing critical maintenance, which the National Nuclear Regulator (NNR) requires to extend its operating licence.

“At Koeberg, we have not been able to meet our own targets. I’m talking about that target of the return of unit 2,” said Ramokgopa.

The primary component of Koeberg Unit 2’s maintenance is replacing its steam generators. In July 2024, Eskom noted that it would soon return to service. However, Ramokgopa says the power utility’s target has slipped.

“We said it will come on this date and it has not come on that date. So, that’s something we are attending to,” the minister said.

Unit 2 is undergoing maintenance similar to that conducted on Koeberg Unit 1 between 10 December 2022 and November 2023. The first unit experienced significant delays, with Eskom missing the initial deadline of July 2023.

Ramokgopa previously said Eskom would use what it learnt from its mistakes during the work on the first unit to ensure a speedier turnaround for unit 2.

The NNR granted Koeberg’s Unit 1 generator a 20-year life extension in July 2024. It is valid until 21 July 2044.

“Koeberg has identified and implemented safety improvements through both French and US nuclear experiences, which have reduced the risk to levels that would normally only be achieved by new, modern nuclear power plants,” said Eskom chief nuclear officer Keith Featherstone.

Due to the extension, Eskom will continue to run Koeberg Unit 1 until January 2025, when it is scheduled for refuelling and further maintenance.

Ramokgopa also described Medupi Power Station’s performance as highly concerning.

“Medupi is a big concern. A number of units had gone out and the like. It’s a concern because it’s one of our newest. It’s a concern because we have invested a lot of money,” he said.

“It’s a concern because we’re pricing that money in the tariff, and then it’s not performing.”

He added that the issues at Medupi are something that Eskom’s teams are focusing on.

The coal-fired Medupi plant is one of South Africa’s newest power stations, but it has been fraught with problems since construction began.

According to former president Thabo Mbeki, Eskom failed to complete the necessary geotechnical work before commencing construction at the site. As a result, Medupi started sinking into the soil when construction began.

Mbeki alleged that the company contracted to prepare the site failed to conduct the tests, significantly increasing costs and resulting in significant delays.

This failure led to significant foundation design changes, delaying the project by 12 to 18 months.

Construction on Medupi commenced in 2007 and was initially set for completion in 2014. However, numerous delays followed, bringing the anticipated completion into 2023.

However, Medupi’s unit 4 generator suffered an explosion shortly after reaching commercial operation in August 2021.

An investigation into the cause of the explosion showed that workers had failed to purge the generator of hydrogen before it mixed it with oxygen, resulting in a large blast.

At the time, Eskom said it anticipated returning the 800MW unit to service by August 2024. Former Eskom CEO André de Ruyter said the repair work would cost approximately R2.5 billion.