Koeberg 2 steam generator replacement postponed

The 930 MWe (net) pressurised water reactor was taken offline on 18 January for a regular refuelling and maintenance outage, the scope of which included the replacement of the steam generators and reactor pressure vessel head. The work is part of plans to extend the unit's operation for 20 years, and scheduled to take five months.

However, Eskom has now announced that it carried out a final review, together with Framatome, the main contractor, of the steam generator replacement (SGR) project "prior to the start of any irreversible work". That review concluded there was a high likelihood of the unit being returned to the grid later than currently planned.

"Due to the potential severe impact of returning this unit later than June 2022 as initially planned, the decision has been made to defer the SGR to the next outage on this unit, planned for August 2023," Eskom said. "This is to avoid the risk of impacting electricity supply during the high demand winter period as the earlier return of Koeberg unit 2 to service will assist in mitigating the risk of loadshedding."

It said the deferral will not impact the safe operation of the unit as the original steam generators undergo a full series of routine inspections and tests to ensure that their integrity is maintained for the next operating cycle. Eskom added that it also does not impact its life extension plan for the Koeberg plant, which requires the replacement of the steam generators on both units.

Since Koeberg 2 was taken offline, the fuel has been successfully unloaded and the majority of work planned in the early part of the outage has progressed as planned, Eskom said. The unit is expected to return to service during June.

The SGR project at Koeberg 1 will proceed as planned, starting in September 2022, the company added. The reactor pressure vessel head of unit 1 has previously been replaced.

The twin reactors at Koeberg were built by Framatome, with unit 1 beginning commercial operation in 1984 and unit 2 the following year. They generate about 5% of the country’s electricity.

In 2014, Eskom signed a ZAR4.4 billion (USD286 million) contract with Areva - now Orano - to design, manufacture and install the replacement steam generators, which each weigh about 380 tonnes and are 20 metres long. They have been made in China under subcontract by Shanghai Electric Power Equipment Company.