- South Africa’s National Nuclear Regulator (NNR) has granted Eskom a licence to continue operating Koeberg Nuclear Power Station Unit 1, that provides 930MW to the grid, for another 20 years until 21 July 2044.
- The plant has been undergoing a life extension programme amidst much controversy, a lack of information and massive cost over-runs. Read more
- Eskom performed a full load rejection test on Unit 1 successfully in January this year after the steam generators were replaced. Read more
- The NNR has not issued a statement or press release on their decision to grant Eskom a licence to continue operating Koeberg Nuclear Power Station Unit 1 at the time of publishing this article.
Eskom affirms that they have operated the Koeberg Nuclear Power Station safely for 40 years and has invested in safety improvements and extensive maintenance to ensure that it continues to operate safely into the future.
“Together with our business partners, we are proud of the achievement that ensures that Africa’s first and only nuclear power plant can now continue to operate safely into the future,” said Bheki Nxumalo, Eskom Group Executive for Generation.
“The granting of the licence is a testament to the hard work and continued commitment of our teams to nuclear safety and Eskom’s generation recovery plan,” said Keith Featherstone, Eskom Chief Nuclear Officer.
“Over the years, 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,” concluded Featherstone.
Next steps
As the Koeberg licence will be changed to reflect an end date of 21 July 2044 for Unit 1, Eskom will continue to operate the unit until January 2025, when the unit will be shut down for its next scheduled refuelling and maintenance outage.
The current licence for Koeberg Unit 2 only expires on 9 November 2025, and the Koeberg Power Station is implementing some of the pre-requisites for Long Term Operation in the current outage. Once the current outage is complete, Unit 2 will be returned to service, and the NNR has stated that the decision regarding the Long Term Operation for Unit 2 will only be made at a later date, but prior to 9 November 2025.
The real gnarly radioactive waste is in the spent fuel pool located underneath the Koeberg Power Station. Image credit: NNR
Issue of concrete corrosion in containment buildings
The NNR has not issued a statement or press release on their decision to grant Eskom a licence to continue operating Koeberg Nuclear Power Station Unit 1. Eskom documents revealed that 40 years of exposure to sea air at Koeberg Nuclear Power Station has damaged the concrete of the containment buildings. At one stage the concrete containment dome was found to have cracked around the entire 110 meter circumference. Read more
The containment buildings are the outer shells of the reactor buildings, built as pressure vessels to withstand the pressure if the reactors inside them ever malfunction and therefore prevent harmful radiation being leaked into the environment.
Eskom has previously responded to the concerns regarding the structural health of the containment buildings. They say that they are fully cognisant of the risk of corrosion of civil structures at the Koeberg Power Station, which is a result of the station being located in a corrosive environment. “Ongoing testing on the Koeberg containment buildings, which house the reactor and associated nuclear components, have proven the structures to be capable of withstanding the most severe accident,” the utility said in the statement.
Eskom conducts tests comprising of quarterly and annual measurements to identify any abnormal movement (such as expansions, settling, etc.), visual inspections to identify physical degradation (such as cracks, spalling, efflorescence) and by performing the Integrated Leak Rate Tests (ILRT) on a 10-yearly basis.
The results of the ILRTs have shown conclusively that the design functions of the containment buildings are met. The test results of the ILRT were also compared with international plants of similar design and it was found to be in-line with industry norms. The ILRT represents the worst case accident scenario and proves the containment buildings to be capable of withstanding the most severe accident.
The main concern to the long term system health of the Containment buildings is the deterioration of the externally exposed concrete surfaces due to chloride ingress that causes reinforcement corrosion and the potential effect on the pre-stressing tendons. Concrete repairs have been implemented to reinstate areas of the external façades where spalling and delamination occurred due to reinforcement corrosion.
A long term solution to prevent rebar and tendon corrosion due to chloride ingress is the implementation of an induced cathodic protection system. This is being implemented as previously recommended by a team of international civil engineering experts.
The information from the ongoing testing, inspections and maintenance is included in the assessments being implemented as part of the work required for Koeberg’s life extension and Eskom remains confident that the issue is fully under control.
Author: Bryan Groenendaal
