Johannesburg - Unit one of the Koeberg nuclear power station would be shut down on Monday for a scheduled maintenance programme, Eskom announced on Sunday.
It said in a statement: "The shutdown... is not expected to result in a shortage of supply to the Western Cape or the rest of the country.
"Koeberg unit one is expected to return to service after its refuelling, inspection and maintenance outage in the fourth week of December 2013."
Eskom said the system would be "tight" for two weeks until two coal-fired generators returned to service from maintenance.
Unit two at Koeberg would remain fully operational.