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
Eskom generation head Bheki Nxumalo has indicated that an extended outage at Koeberg Unit 2, which started on December 11, is expected to continue until September 2024, increasing the prospect of both Koeberg units being out of service simultaneously from late July 2024.

In an update on the outage schedule during a briefing on the implementation of the Energy Action Plan on December 10, Nxumalo confirmed that Unit 1 had been ramped up to 924 MW.

This followed the unit’s much-delayed outage during which its three steam generators were replaced. Unit 2’s steam generators will be replaced during the December 2023 outage.

The replacement forms a key part of Eskom’s application to the National Nuclear Regulator (NNR) for authorisation to operate Koeberg’s two pressurised water reactors for a further 20 years, after their 40-year licence expires.

The licences for both units will expire on July 21, 2024; the same date on which Eskom currently intends removing Unit 1 for another 200-day-plus outage to conduct compulsory works in line with a ten-year maintenance cycle, including crucial containment building leak tests.

However, Eskom has indicated to Engineering News that, for operational reasons, it would “definitely like to shift the start of the next outage on Unit 1”.

Such a move would depend, however, on a “positive Long-Term Operation (LTO) decision by the NNR”.

The NNR is conducting a public participation process on the LTO Safety Case, which was submitted by Eskom in June 2022, and will host three sets of public hearings in February ahead of a final decision in July.

Eskom has also applied to the NNR to have the unit 1 and 2 licences separated to reflect that Unit 2 entered into commercial operation on November 9, 1985; more than a year after Unit 1, on July 21, 1984.

The NNR has completed a review of the decoupling, including an assessment of some components shared by both units such as the seismic bearings and cables. The NNR board will make a decision before the end of January 2024.

Should the decoupling approval be followed by an LTO approval, Eskom might be able to shift the 200-day-plus maintenance out, presumably until after Unit 2 resumes production with its three new steam generators.

Should the decoupling and LTO be refused, both units will be out of service from July 21.

Nxumalo has expressed confidence in the case Eskom has proposed for the separation of the licences and has indicated that a positive decision could provide it with some operational flexibility, should the LTO also be approved.

By July 21, 2024, Unit 1 would have been in operation for just over seven months; there would, therefore, be scope for it to continue operating, should an NNR LTO authorisation be in hand.

“But we don't want to preempt issues at this stage. The first thing that we must work on is to get that approval for the life-extension of Koeberg,” Nxumalo has said.

Eskom told Engineering News separately that, based on the reviews performed and international experience, it “remains optimistic that the NNR will issue the licence for LTO”.

As long as this is received before the date specified in the current licence, then it is unlikely that both units will be out of service simultaneously.

Nevertheless, both units will still have to undergo the mandatory ten-year maintenance tests in the coming two years, with the tests on Unit 1 having been previously been conducted in 2015 and on Unit 2 in 2016.

Therefore, even if Eskom can avoid having both units out simultaneously from July 21, 2024, there will still be long periods, from now until 2026, when only one unit will be producing at any time.

The absence of a single Koeberg unit typically adds a full stage to the intensity of loadshedding.

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.