Eskom said all protocol was observed when the unit was shut down. (David Harrison/M&G)
Last week’s sudden and surprising tremors may have caught Capetonians off guard. However, anti-nuclear campaigners have for years requested access to a study conducted in 2017 by the National Nuclear Regulator (NNR) explicitly looking at the seismic risk posed to the Koeberg nuclear power station, which lies 30km north of Cape Town.
According to the Koeberg Alert Alliance, the organisation has sent the regulator numerous Promotion of Access to Information applications, to no avail. Neither this report nor any other reports focused on the effects of seismic activity on Koeberg have been released to the public.
Meanwhile, Eskom’s chief nuclear officer at Koeberg, Riedewaan Bakardien, said although there is an appreciation of the potential risk, calculations indicate that such risk is minuscule. He added that the plant had been designed to withstand much stronger earthquakes.
Construction on the Koeberg facility began in 1976, with the plant commissioned in 1984. Bakardien said Koeberg was built on what can be likened to “shock absorbers”, which can withstand horizontal and vertical movements up to the equivalent of a magnitude-seven quake on the Richter scale.
“The plant is built on what is called a seismic raft. We also know that a seven-magnitude quake is well above what we have seen in the immediate area and the country. The plant was specifically designed to cater for its location in the Western Cape at the Koeberg site. The design features are quite robust,” he said.
But that hasn’t stopped anti-nuclear campaigners from raising the red flag about what it calls “secretive” safety information.
The spokesperson at the Koeberg Alert Alliance, Peter Becker, said it was an “unscientific statement” to say that there is no risk to Koeberg.
“The question is how do we quantify that risk and then do some balance between the risks and the benefit. There’s a worrying atmosphere of secrecy at Koeberg, Eskom and the National Nuclear Regulator. Our request for the report, which was refused, is puzzling because if there’s nothing to hide then shouldn’t that scientific study be made public?” Becker said.
“If you take the Fukushima disaster and you ask that plant operator the day before that disaster whether their plant is safe, what do you think they would say? Of course, everyone thinks it’s safe until the unexpected happens. We didn’t expect a global pandemic, we don’t expect a massive earthquake in Cape Town and we don’t expect a nuclear disaster. But that doesn’t mean it could never happen.”
On Saturday last week, two quakes, hours apart, struck in or near South Africa. The first, a 6.2 magnitude earthquake hit 1 900km southeast of Cape Town. The seismic activity occurred at the active divergent plate boundary separating the African and Antarctic tectonic plates. In a separate tremor, the South African Council for Geoscience said it registered a 2.5 magnitude earthquake at Malmesbury.
The subsequent rumble and vibrations were felt by many Cape Town residents on Saturday night, with aftershocks on Sunday. The Koeberg nuclear plant is about 50km away from Malmesbury and is built close to the Milnerton fault line.
Responding to last weekend’s events, the NNR said it would conduct independent inspections to assess whether the tremor had any effect on the Koeberg infrastructure.
“We are maintaining ongoing communications with the Koeberg nuclear power station and will continue to monitor Koeberg’s response to the situation closely,” said NNR chief executive Bismark Tyobeka.
Earlier this year, the Koeberg Alert Alliance raised concerns about the planned extension of the Koeberg lifespan after the department of minerals and energy agreed that a public-participation process may have to be held again, because it fell within the coronavirus lockdown period.
The power plant, which was originally scheduled to be decommissioned in 2024, is now expected to operate for another 20 years, until 2044.
Despite this, Koeberg’s Bakardien said he encourages communities to make requests for safety information, which will be made possible if available.
“If there’s anything needed from Koeberg, we respond to those requests. We are dealing with a few requests of that nature at the moment, and we’ll share that information when we have it,” he said.