Name of the Project
Koeberg nuclear power plant steam-generator replacement (SGR) project.

Location
Western Cape, South Africa.

Project Owner/s
Eskom.

Project Description
The current steam generators in Unit 1 and Unit 2 at the Koeberg nuclear power station have been in operation since 1984 and 1985 respectively. The aim of the project is to extend the design life of the nuclear power station by 20 years to 2045.

The project involves the replacement of all six steam generators for units 1 and 2.

The SGR project involves the design, manufacture and installation of three steam generators in each of the Koeberg power plant's two operating units, as well as safety analyses and studies to comprehensively demonstrate the plant's design integrity, with no adverse impact on public and worker safety and health or the environment, including the enhancement of nuclear safety.

The new generators will incorporate modern design features for easy maintenance and inspections and improve heat-transfer efficiency, leading to an overall efficiency improvement of Koeberg.

The installation of the generators will be conducted during the scheduled refuelling, inspections and maintenance outages of the two units at Koeberg power station. Eskom is on track and progressing according to plan for installation during the next unit 1 and 2 outages.

The other major components of the life-extension plan include:

• a refuelling water storage tank replacement project, completed in 2019.
• the Unit 2 reactor pressure vessel head replacement, with the installation thereof scheduled for 2022.
• the replacement of feed-train components on the conventional power plant, which is conducted during maintenance outages.
• the ongoing Koeberg safety aspects of long-term operation assessment. The assessment is designed to provide the equipment-ageing management confirmation to enable the Koeberg plant to operate beyond its original life span of 40 years to at least 60 years.

Capital Expenditure
Not stated.

Planned Start/End Date
Not stated.

Latest Developments
The return of Unit 1 to commercial service had been delayed by a further ten days, as some critical tests were still to be completed before the reactor is started, Engineering News reported on October 20.

The most recent date that Eskom provided for the return of Unit 1 was November 3. It is now expected to be returned to service on about November 13.

Unit 2 will then be taken offline to replace its steam generators.

The entire project is massively behind the original schedule, which was planned for 2022. The project was initially expected to take 12 months.

In a detailed reply to questions, Eskom head of nuclear Keith Featherstone said the steam generator replacement was complete, but some tests remained before the turbine could be set spinning to prepare for synchronisation to the gird. The unit would be commercially available once all tests were completed.

“During the startup, as all the activities are in series and a precursor to the next activity, any emerging defect becomes a delay to the plan, as it has to be fixed before the plan can continue,” Featherstone noted.

"Achieving each of the milestones involves the completion of many tests to verify all the safety systems are operating correctly. Up until now, the delays have centred around the review of the stroke times of values measured during the performance of the tests, as we have to assess deviations from previous values and ensure they are adjusted properly."

The primary circuit is in "hot shutdown condition" – during which it operates at 155 bar and close to 300 °C, but the reactor has not yet been started.

The schedule to complete the refurbishment on both units before the licence expires is under pressure. While Eskom expects that replacing the steam generators in Unit 2 will be quicker, it has taken ten months to complete Unit 1. 

In a further complication, Unit 1 must be taken offline again in July 2024 for 200 days to conduct the remaining pressure tests on the container building. There is, therefore, a risk that the two units will be offline simultaneously.

To avoid this, Eskom has applied to the National Nuclear Regulator (NNR) to revise the licence with two stop dates, one for each unit, as Unit 2 came into commercial operation more than a year after Unit 1. If granted this permission, Eskom can complete the pressure tests on Unit 1 before Unit 2 is taken offline. 

"We are still awaiting a decision from the NNR as to whether they will include separate dates for Unit 1 and Unit 2 . . . The planned 200-day shutdown of Unit 1 will change only once we have clarity on the long-term operating licence from the NNR, as we do not know if they will impose any requirement," Featherstone explained.

Key Contracts, Suppliers, and Consultants
Framatome (main SGR contractor); General Electric (modifications to the balance of plant or secondary turbine system); and Jacobs Engineering (balance of plant hardware changes).

Contact Details for Project Information
Eskom media desk, email mediadesk@eskom.co.za.