Eskom quashes Koeberg contamination reports — The Koeberg nuclear power station north of Cape Town. Image: Eskom

Eskom has denied that workers at the Koeberg nuclear power station suffered radioactive contamination requiring iodine treatment. This is after weekend media reports alleged that about 150 employees and contractors were exposed in incidents at the plant this month.

News24 reported on Sunday that around 150 Eskom employees and contractors are believed to have suffered internal radioactive contamination in three separate maintenance-related incidents at the plant, about 40km north of Cape Town, with some workers reportedly requiring iodine treatment.

In a statement on Sunday, Eskom confirmed that “highly sensitive radiation monitoring equipment detected two brief and localised airborne radioactivity events” inside the containment building of Koeberg unit 2 – on 2 and 7 July – during inspections of the unit’s steam generators. But it said no radiation leak occurred, that there was “no impact on employees, the public or the environment”, and that “no iodine tablets needed to be administered to employees”.

The events have been classified as “level 0” – “no safety significance” – on the International Nuclear and Radiological Event Scale, the lowest possible rating, Eskom said, and the National Nuclear Regulator was informed in line with regulatory requirements.

The detections occurred during eddy current testing – a robotic inspection technique used to check steam generator tubes for wall thinning. Eskom said microscopic oxide particles, known in the industry as “crud”, became airborne in the enclosed work area as inspection probes moved through the tubes, describing this as “a well-understood and documented phenomenon” at pressurised water reactors worldwide. Monitoring equipment triggered an automatic alarm, work was stopped, the area secured and filtration systems cleared the air before inspections resumed, it said.

Outage

Notably, the tubes under inspection belong to Koeberg unit 2’s new steam generators, installed during the multibillion-rand replacement programme that underpinned the plant’s 20-year life extension. Unit 2 has been on a scheduled outage since April – its first major inspection cycle since returning to service with the new generators in December 2024 – and Eskom said the outage remains on track for completion in November. Unit 1 is operating normally.

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The disclosure timeline is likely to draw scrutiny: the detections occurred on 2 and 7 July, but Eskom made no public statement until Sunday, 12 days after the second event and only once media reports had surfaced. The regulator was informed, but residents near the plant first learnt of the events from a denial.