Koeberg offline for replacement of steam generators

Plant owner and operator Eskom said that it followed 450 days of uninterrupted operation. The refuelling is the 25th since the 920 MWe unit was commissioned.

Unit 1 is scheduled to be taken offline later in the year, with its three steam generators also being replaced, but not its reactor pressure vessel head, which was replaced several years ago.

"This is going to be a long, but needed, outage - the first of its kind for Koeberg. Our staff are prepared and committed to make history by ensuring the success of this project," said Riedewaan Bakardien, Eskom’s Chief Nuclear Officer.

"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 company described the replacement of the steam generators as a "precautionary safety measure".

Eskom added that the replacement work was an important element of the safety submission being prepared for South Africa’s National Nuclear Regulator (NNR) in support of its application to extend operations by 20 years, beyond 2024.

The twin pressurised water reactors (PWR) at Koeberg were built by Framatome, with unit 1 beginning commercial operation in 1984 and unit 2 the following year. They generate about 5% of the country’s electricity.

The current unit 2 steam generators have been in use since it began operations in 1985. On removal they will be stored on site, packaged and dismantled for final disposal at the national nuclear waste repository.

_{The first replacement steam generators arrived at the site in 2020 (Image: Eskom)}

In 2014, Eskom signed a ZAR4.4 billion (USD285 million) contract with Areva - now Orano - to design, manufacture and install the replacement steam generators, which each weigh about 380 tonnes and are 20 metres long. They have been made in China under subcontract by Shanghai Electric Power Equipment Company.

Eskom said the outages at the Koeberg plant, which is near Cape Town, were planned to take place at times of the year which minimise the impact on overall electricity supply, but said the length of the outages meant "the electricity supply system may be under additional strain during the coming year".