Eskom’s Koeberg nuclear reactor going critical

Eskom’s Koeberg refurbishment has overcome a significant hurdle, with the National Nuclear Regulator (NNR) giving it the green light to take the reactor critical after all required tests have been completed on the revamped Unit 1. 

This was revealed in a social media post from energy analyst Chris Yelland. 

Koeberg has two generating units capable of producing 920 MW each, roughly equivalent to one stage of load-shedding per generating unit.

The nuclear power plant is being refurbished to extend its operating life, with the steam generators in both units set to be replaced. 

The steam generator replacement on Unit 1 was initially supposed to occur between February and June 2021, while the replacement on Unit 2 was set to occur between January and May 2022. However, both projects were delayed to 2023.

The refurbishment was set to begin in January 2022, but numerous delays meant it only started in mid-December 2022. 

Eskom has previously extended the expected date for the return to service of Unit 1 several times from the initial indicated completion date of mid-June 2023. 

Unit 1 was expected to be synchronised to the grid by 30 October 2023 and to return to commercial operation at full output by 13 November 2023.

Yesterday, Yelland revealed that Eskom’s chief nuclear officer, Keith Featherstone, told him that all the required tests had been completed on the reactor of Unit 1. 

Furthermore, the utility received the green light from the NNR to take the reactor critical and begin to generate electricity again. 

However, Unit 1 has still not been synchronised to the grid after an eleven-month outage due to some emergent issues on the turbine side of the plant.

Featherstone told Yelland that Eskom is attending to the problems on the turbine side of the nuclear plant but did not give any indication as to when Unit 1 would be re-synchronised to the grid or deliver full power. 

Energy analyst Chris Yelland

Potential Koeberg shutdown

Yelland has said previously that the numerous delays to the Koeberg project will increase the risk of its operating licence, which expires on 21 July 2024, not being renewed by the NNR. 

Eskom has indicated that even after the 9-month outage of Unit 1 in 2023, it still needs to conduct a series of overpressure tests on the concrete containment building. 

The containment building is an essential safety structure intended to contain nuclear radiation in the event of an accident or melt-down of the nuclear reactor.

It has previously been reported that in the past 40 years of operation, significant cracks have appeared in the concrete of the containment buildings at Koeberg.

The buildings now need to be properly overpressure tested to ensure that radiation cannot leak out in the event of an accident.

Eskom has applied to the NNR for separate expiry dates for Unit 1 and Unit 2 based on the rationale that Unit 2 was commissioned about 18 months after Unit 1. Eskom is still awaiting a decision from the NNR in this regard.

If the NNR decision in respect of a separate extended expiry date is not granted, then it is possible that both Unit 1 and Unit 2 may have to shut down on 21 July 2024.

The NNR announced on Wednesday that it will hold a new round of public hearings on the renewal of Koeberg’s operating licence in February.


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