Koeberg life extension project is behind schedule before it even begins

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 megawatt (MW) nuclear reactors, as well as the replacement of the reactor head, control rod drive mechanism and instrumentation cables in the reactor core on one of the reactors.

Life extension work also involves:

  • Replacement and expansion of the PTR (reactor test pool) storage tanks used to store borated water for the reactor cavity and the spent fuel cooling circuit;
  • 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 elements on pressurizers; and
  • 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.

Delays

However, Eskom’s nuclear director Riedewaan Bakardien said the Omicron variant and the impact of the coronavirus pandemic, which has led to travel restrictions and the implementation of additional protocols, “s’ has proven to be a challenge to secure some of the required international resources on site in 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.

Read: Eskom’s investment in R3bn Ankerlig power plant to support Koeberg

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 has been left out in terms of cross-cutting impacts.

“This final approval for plant modifications is usually issued one month before the onset of an outage,” Eskom explains.

Load shedding impact

The shutdowns of the Koeberg reactor for extended life come at a time of severe constraints on South Africa’s electricity supply.

In 2021, these constraints resulted in a record 1,136 hours of load shedding, with the associated loss of some 1,773 gigawatt hours (GWh) of electricity for the productive economy.

Work to extend the life of the Koeberg power plant will reduce the available generation capacity in South Africa by approximately 900 MW, with the two nuclear reactors being shut down in succession, each for periods of approximately five months.

The project therefore increases the probability and risk of load shedding during 2022 and the first quarter of 2023, and any exceeding of the planned shutdown periods of either reactor will prolong the risk and consequences of load shedding.

Read: Why nuclear should be part of our just energy transition

Worst case scenario

In the unlikely event of extended time overruns resulting from serious unforeseen circumstances, the worst-case scenario would be if 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 (1,840 MW) until the reactors can safely restart, once all work has been completed and a new operating license has been granted. .

Eskom makes an effort to stress that while the “green light” has not yet been received from the NNR to proceed, this is not a cause for 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.

Read: SA’s nuclear power housekeeping costs – who will foot the bill?

Eskom’s safety case for the steam generator life extension and replacement project is currently under review by the NNR and, according to Bakardien, no new developments have occurred as a result of the formal review. 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 expects final NNR approvals to be received within the next two weeks and that work on replacing the steam generator will begin in early February.

Chris Yelland is Managing Director of EE Business Intelligence.

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