State-owned power producer Eskom has shut down unit one of its Koeberg nuclear power station in the Western Cape, for its scheduled refueling, maintenance and upgrading.

The shut down started on Monday January 26, and the refueling was expected to be completed by May.

“This major outage focuses on maintenance and upgrading activities that will take place at the same time as the refuelling of the reactor.

“This outage has been planned for, and the duration factored into the overall generating maintenance plans for all of Eskom’s power stations,” the utility said in a statement.

During this period when Koeberg unit 1 was not generating electricity, the Cape region would be supplied from Koeberg Unit 2, and the transmission transfers from power stations in the north of the country. 
Unit 2 of Koeberg was shut in November, owing to a to a technical fault. Repairs to the 900-MW unit ensured it was up and running again by December. Unit 1 of Koeberg was also shut down for a week in August 2008 for unplanned maintenance.

The current scheduled maintenance would likely be carefully watched, after previous maintenance and refueling activities in November 2005 led to a bolt being left in the stator after maintenance. More than half of the stator bars (electrical wiring inside the stator) were damaged, as well as the cooling systems of the generator (both the stator and the rotor). This affected the supply of electricity in the Cape, causing rolling blackouts in the region.

Eskom stated that in order to meet the morning and evening peak requirements, additional power plants in the Cape would be used. 

These included the hydro and pumped-storage units and the two new open-cycle gas turbines, namely the Gourikwa and Ankerlig power stations. 

Two more units have recently been commissioned at the Gourikwa power station, bringing to five the number of units operational at Gourikwa.

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