The installation of six new steam generators at Eskom’s Koeberg nuclear power plant, which was due to start on January 5, 2022, appears to be behind schedule before it has even started.
The Koeberg Power Plant, located on the west coast of South Africa about 35 km north of Cape Town, is nearing the end of its 40-year lifespan and operating license.
However, in 2022 and early 2023, the nuclear power plant is expected to undergo a number of upgrades in order to extend its lifespan by 20 years.
This includes the replacement of three steam generators on each of Koeberg’s two 920 MW nuclear reactors, as well as the replacement of the reactor head, control rod drive mechanism and instrumentation cables in the core of the reactor. reactor on one of the nuclear reactors.
Other work for the extension of the service life involves:
- Replacement and expansion of PTR storage tanks used to store borated water for the reactor cavity and spent fuel cooling system.
- Repairs, modifications and monitoring of the reactor containment building to include cathodic protection to prevent corrosion of steel reinforcement (rebar) in concrete.
- Replacement of heating resistors on pressurizers.
Other factory modifications and upgrades for reliability and durability, such as transformer replacements, digital system upgrades, safety system upgrades, cooling water systems, piping and heat exchangers.
The project to replace the six steam generators has been underway for several years.
However, Eskom’s nuclear director, Riedewaan Bakardien, says the Omicron variant and the impact of the coronavirus pandemic, which has led to travel restrictions and the implementation of additional protocols, “has proved a challenge to secure some of the required international resources locally. on time”.
In the meantime, Eskom says it is busy finalizing the installations to support the project team during the life extension work. This includes the installation and load testing of large cranes which are critical to project lifting operations.
Another stumbling block is that the safety case for the Eskom facility has not yet been approved by the National Nuclear Regulator (NNR), and the NNR ‘green light’ to start work has not yet been approved. still not been received.
The NNR normally gives its final approval once it has completed the detailed reviews of all major work that would be performed during a shutdown to ensure that nothing is missing in terms of cross-sectional impacts.
“This final approval for factory changes is usually issued a month before the start of a failure,” Eskom explains.
The reactor shutdowns at Koeberg for life extension come at a time of severe power supply constraints in South Africa. In 2021, these constraints resulted in a record number of 1,136 hours of load shedding, with the associated loss of some 1,773 gigawatt hours (GWh) of electricity to the productive economy.
Extending the life of the Koeberg nuclear power plant will reduce the available generation capacity in South Africa by approximately 900 MW, with the two nuclear reactors being shut down in turn, each for periods of approximately five months.
Extending the lifespan therefore increases the likelihood and risk of load shedding in 2022 and the first quarter of 2023, and any overrun in the planned shutdown periods of either reactor will extend the risk. and the consequences of load shedding.
In the unlikely event of extended time overruns resulting from serious unforeseen circumstances, the worst-case scenario would be that the life extension project is not completed by the time the current operating license expires in 2024.
In this situation, the NNR may require the shutdown of the entire plant (1840 MW) until the reactors can safely restart, after all work has been completed and a new operating license granted.
Eskom tries to stress that while the “green light” has not yet been received from the NNR to proceed, this is not of concern. Eskom says it is committed to ensuring all NNR requirements are met, even if more work is needed in the final days of preparation.
Eskom’s safety case for the Steam Generator Life Extension and Replacement project is currently under review by the NNR, and according to Riedewaan Lakardien, there have been no new developments arising from the review. official of the NNR.
“The NNR provided Eskom with a positive opinion of the safety case as the review progressed, but final approval is only granted when the NNR is 100% satisfied and all issues raised have been resolved, ”he adds.
The utility says it hopes final NNR approvals will be received within the next two weeks and work to replace the steam generator will begin in early February 2022.