Durban – Eskom says its decision to delay work at the Koeberg Nuclear Power Station came after “a careful assessment”.
In a statement on Thursday, Eskom said delaying the start of the outage of Unit 1 of the Koeberg Nuclear Power Station is to allow time to stabilise the system and the recovery of some generation capacity.
Eskom said Koeberg Unit 1 had been online for 407 days since the last outage.
“The Koeberg Unit 1 refuelling and maintenance outage is therefore planned to now commence on Saturday, December 10, should the grid conditions have recovered to ensure stability of the system,” the utility said.
According to acting chief nuclear officer, Sadika Touffie, while Eskom was ready to commence with the outage, with the contractors and all the requisite resources on standby, grid stability was an important consideration prior to shutting down the Unit 1 reactor to commence the maintenance and refuelling outage.
“This is going to be a long but necessary outage – the first of its kind for Koeberg. Eskom has taken care to ensure no undue delays are experienced once the project gets under way,” Touffie added.
Eskom said the outage will be for approximately six months.
“The extended unavailability of the unit means the electricity supply system may be under additional strain during the outage,” the utility said.
This will be the 26th refuelling outage on Unit 1 since commissioning and will also see the replacement of the unit’s three steam generators as part of the long-term operation at the power station. The reactor pressure vessel head on this unit was replaced several years ago.
Touffie said Koeberg was an important part of the Eskom generating fleet due to its reliable operation, low primary energy costs, its strategic location in the Western Cape to stabilise the national electricity grid and was a clean source of energy.
“Unlike other types of power stations, where fuel can be added to continue generating power, the fuel at a nuclear power station is sealed inside a reactor vessel, which is opened for refuelling every 15 to 18 months.
“This is also a time when the station will perform certain required inspections on equipment and perform more intrusive maintenance that cannot be performed when the unit is online,” Touffie said.
The rigorous maintenance, inspection and testing programmes are some of the critical activities that ensures that the plant remains safe and able to deliver this reliable level of performance.
Eskom said the Koeberg units, at 920MW each, are the largest generating units on the African continent.
Touffie said the safe and reliable operation was a significant contributor to meeting the country’s electricity demand. The Koeberg outages are planned at times of the year when the impact on the overall electricity supply is minimised as far as possible.