Thyspunt seismic study needed

Analysis still not redone five years after Eskom assessor’s admission

A recent earth tremor in the Southern Cape has thrown up questions around the seismic stability assessment of Thyspunt, where Eskom wants to build a nuclear reactor. The October 18 tremor was relatively slight on the Richter scale.

But its proximity to Thyspunt near Oyster Bay, memories of Japan’s Fukushima disaster where a deadly tsunami was sparked by an earthquake, and research showing how climate change could increase the number and severity of seismic events worldwide, prompted The Herald to dig deeper.

With Eskom and the Department of Energy pressing to launch the nuclear procurement process, one of the startling points to emerge was that the utility’s own assessor recognises the need for a comprehensive new seismic study.

And five years after this admission, it appears this study has not been done.

In a March 20 2011 letter to the Koeberg Action Alliance (Kaa) in response to the nuclear watchdog’s comments on the assessment process, Arcus Gibb wrote that “it is acknowledged that the PSHA [probabilistic seismic hazard analysis] needs to be redone using a different methodology . . . ”

He said further, “a new two- to three year PSHA will be undertaken . . . by a multidisciplinary, multinational team of scientists and reviewed by a panel of . . . internationally recognised specialists”.

“There is need for additional work before the green light can be given for the development of a nuclear power station at any of these sites.

“But unfortunately such a PSHA had to be postponed due to financial constraints,” Gibb wrote.

Kaa spokesman Peter Becker said yesterday this assessment had apparently still not begun.

“The original seismic study was dated October 2009, and has not been updated since, apart from having the date at the top changed to March 2011.”

Gibb’s final impact report on the nuclear project was now being considered by Environment Minister Edna Molewa, Becker noted.

“It is a poor report for many reasons including the seismic component and we are hoping she will rule that the project cannot go ahead.”

No comment had been received from Eskom by the time of going to print.

Meanwhile, research led by Professor Bill McGuire of University College in London shows that climate change is adding another dangerous factor.

McGuire warns melting ice sheets and glaciers, snow caps and tundra are swelling our seas and changing the pressures on Earth’s sensitive outer “rind”.

This is causing it to “bounce and bend”, and triggering an increase in the number and severity of volcano eruptions and quakes.

McGuire first published his work in 2012 but was most recently quoted last month in The Insurance Journal, where he was asked to name the greatest geological threat from climate change.

“It might well be the onset of seismic activity in areas that have so far not experienced it in modern times,” he said.

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