Power utility Eskom has advised that Unit 2 of the Koeberg nuclear power station was taken offline on January 17 for refuelling and a five-month maintenance outage, which may strain overall electricity supply in the country.

The exercise will see the unit’s three steam generators replaced. The reactor pressure vessel head will also be replaced, with Eskom reporting that this will be a first for the plant.

Prior to the maintenance outage, Unit 2 had been operating uninterruptedly for 452 days since its last refuelling outage in October 2020.

A similar maintenance outage is scheduled for Koeberg Unit 1 later in the year, during which its steam generators will also be replaced. 

The two Koeberg units, at 920 MW each, are the largest nuclear power generating units in Africa.

Eskom says that, although the maintenance outages are planned at times of the year when the impact on the overall electricity supply is minimised as much as possible, the extended unavailability of the units may place additional strain on the grid.

Eskom chief nuclear officer Riedewaan Bakardien says this will be a long but necessary outage.

“Nuclear safety is the paramount factor. We will progress the outage work diligently, making sure nuclear safety and safety of plant, personnel and public is top of mind.”

The equipment replacement is a precautionary safety measure and key to extending the life of the plant.

The successful replacement of the steam generators and reactor pressure vessel head is an important element of the safety submission being prepared for submission to the National Nuclear Regulator in mid-2022, in support of extending Koeberg’s operations for 20 more years.