French company Alstom has signed a R1.6-billion contract with Eskom to retrofit the low-pressure turbines of the two 970 MWe units at Koeberg Nuclear Power Station.

"The retrofit will increase the station's power output by over 65 MW, improve availability and reliability, as well as extend the lifetime of the plant," Alstom said in a statement on Friday.

"The retrofits will be carried out during planned refuelling outages, thus reducing the chance of interruption to generation from the station." Alstom said.

Eskom and Alstom have worked together on previous projects such as the retrofitting of the Arnot power plant, an integrated retrofit project providing a capacity increase to that station of more than 300 MW.

Eskom recently placed orders for new equipment contracts with Alstom for the Medupi and Kusile coal-fired power plants producing 4800 MW each, the statement said.

Alstom has installed more than 180 new turbine islands and retrofitted 220 rotors on nuclear plants worldwide.