The National Nuclear Regulator (NNR) has asked Eskom to undertake additional engineering studies on the Koeberg power station before it can deliberate on its application to extend the long-term operation licence for another 20 years. 

Speaking at a briefing to editors in Johannesburg on Thursday, Eskom's senior manager in its outage centre, Thabiso Moirapula, said that Eskom did not know yet if the licence for the 40-year old plant will be extended before it runs out in July 2024.

The utility has also asked the NNR to split the licence into two and extend it for Unit 2, enabling Eskom to run it for a while longer, and allowing for more flexibility in the refurbishment process.

"There is ongoing engagement with NNR. The safety case was presented by Koeberg, and the NNR has asked for additional engineering studies to be completed. We think our application has a prospect of success, although the NNR is not saying when it will decide," he said.

The NNR cancelled a scheduled press briefing on the licence two weeks ago until further notice without explanation. 

Koeberg plays an important role in the power system, with its two units delivering 900MW, the equivalent of two loadshedding stages.

Eskom is engaged in a major operation to extend the plant's life through the replacement of the steam generators, of which there are three in each unit. 

Moirapula did not elaborate on the concerns of the NNR. Anti-nuclear activists have repeatedly raised fears over the weathering and erosion of the containment buildings that house the reactors. When the steam generator project is completed, Eskom intends to conduct pressure tests on the buildings, requiring another 200-day outage for each unit.

The replacement of the steam generators has been on the cards since 2010 but has been delayed numerous times. The project, which finally began in January with Unit 1, has hit numerous obstacles, with the return date now scheduled for November, four months later than planned.

'We all understand the consequences'

Minister of Electricity Kgosientsho Ramokgopa asked the Eskom board to provide a report on the status of the steam generator project after he said a briefing from Koeberg executives left him "in the dark" about the delays. 

During the project, Eskom and French nuclear contractor Framatome have clashed repeatedly with Framatome having lodged around 200 claims for delays, running into billions. The disputes, which will likely only be resolved in arbitration hearings in Paris, have raised the issue of the cost of the steam generator replacement. 

When Eskom first mooted the project, the projected cost was R20-billion. While the claims from Framatome could raise the cost of the project, a very large portion of the R20-billion contract value was paid upfront several years ago. This means Framatome needs more to gain financially from the contract, giving rise to speculation on the motivation behind the barrage of claims.

"A very small portion of the contract value remains to be paid. It is fair to assume this is why we face so many claims. We are addressing this," Cassim said.

Due to Koeberg's importance in the system, Eskom hopes to avoid taking two Koeberg units off simultaneously. 

"It is a key part of our long-term strategy that we do the steam generator life extension. We all understand the consequences if we get to 24 July and the life extension has not been done," said Cassim. 

As things stand now, Unit 1 is scheduled to return in November. Unit 2 will then be taken off for the steam generator replacement and returned by July 2024. Unit 1 will then be taken off again in July 2024 for the 200-day pressure test.

In a statement last week, Eskom said that the main engineering work on replacing the steam generators in Unit 1 had been completed. 

SA will therefore be without one unit of Koeberg for an extended period. Any delays to the programme will result in both units being down at the same time.