After almost a year offline, Unit 1 at Koeberg power station has been successfully synchronised to the grid, Eskom announced on Saturday, 18 November. 

The outage at Unit 1 began on 10 December 2022 for the maintenance, refuelling and the replacement of three steam generators. Its return to service has been affected by delays. Most recently, in August, Daily Maverick reported that Eskom’s chief nuclear officer at Koeberg nuclear power plant, Keith Featherstone, said the unit was meant to return to service by 3 November. 

Read more in Daily Maverick: Koeberg power station’s Unit 1 set to be finally back online by November — Eskom

In Saturday’s media release, Eskom said the synchronisation came “after almost a year and the longest outage in the history of the station, during which the original three steam generators were successfully replaced by three new steam generators”. 

It was “a huge milestone in the generation operational recovery plan and Eskom’s strategic objectives”, the utility said. 

Eskom group executive for generation, Bheki Nxumalo, said: “This milestone is a result of the hard work and determination of the Eskom employees, suppliers and contractors who have had to endure a long and challenging outage in the Koeberg power station’s history.” 

Koeberg – situated in the Western Cape – is the country’s only nuclear power station, with a total generation capacity of 1,860MW, about 5 % of Eskom’s total generation capacity. 

Read more in Daily Maverick: Further delay in life extension of Koeberg nuclear reactor worsens power outlook

Unit 2 outage

Eskom said for the duration of the outage at Unit, Unit 2 had been safely generating electricity into the grid. It will continue to do so until the start of its next outage, which will include the replacement of its three original steam generators. Unit 2 will be shut down for refuelling, maintenance and replacement, similar to the outage at Unit 1. 

“Although Unit 2 outage will be similar in terms of the scope, the lessons learnt from Unit 1 outage will enable the duration to be reduced; however, as was the case during the Unit 1 outage, nuclear safety will not be compromised,” Eskom said. 

According to Eskom, the replacement of the steam generators is a huge milestone in the life of Koeberg, as it was identified by Eskom as a “prerequisite”for the extension of the operating licence for Koeberg. 

It is part of the process to extend Koeberg’s original design life of 40 years. Eskom says the National Nuclear Regulator is already evaluating a licence application from Koeberg to extend its operating life by 20 years.

According to energy expert Chris Yelland, if an application for Unit 2’s extended expiry date is not granted, then it is possible that both units may have to shut down on 21 July 2024.

‘Significant failure’

Meanwhile, in his weekly briefing on Sunday morning, Minister in the Presidency responsible for Electricity, Kgosientsho Ramokgopa, said unplanned grid losses in the past two weeks were a “major disappointment”. In the weeks before, there had been no scheduled power cuts. 

Ramokgopa said there was a “significant failure of a cluster of units” at Eskom, including at Medupi, Camden, Duvha, Lethabo, Kriel and Hendriena. The unit offline at Medupi was “a really big unit”, he said. 

Ramokgopa said the failure caused a loss of 2,000MW, which was “just shy of three stages” of scheduled power cuts. 

He said five units should come back online by midnight and the others should come back tomorrow. DM