Cape Town - Koeberg nuclear power station is sitting alongside a geological fault which gave rise to an earthquake in 1809 that was the same magnitude as last month’s earthquake in Christchurch, New Zealand.
The Milnerton fault lies about 8km offshore of Koeberg.
New Zealand’s earthquake, which killed 145 people, measured 6.3 on the Richter scale. Cape Town’s earthquake 200 years ago, which had its epicentre in present-day Milnerton, is estimated to have measured between 6.3 and 6.5.
Several earthquakes in Cape Town have been recorded from this fault, including a small one in May 2009.
Seismic experts have rated the earthquake risk as “rare, but a very real threat for Cape Town”.
The government intends doubling South Africa’s nuclear power capacity and, in spite of the earthquake risk, Koeberg has been selected as one of the sites for more nuclear stations.
Eskom says it is aware of the fault line, but has built Koeberg to withstand an earthquake of 7.
According to a paper published by the Council for Geoscience in Pretoria, the Milnerton fault has given rise to several earthquakes, the first of which occurred “very close to Cape Town” in 1620. There was another in 1811, but the strongest was on December 4, 1809. The epicentre was at a place called Jan Biesjes Kraal, the site of today’s Royal Ascot housing estate in Milnerton.
A visiting naturalist, Wilhelm von Buchenroder, recorded the events five days after the earthquake. He wrote: “Near the Kraal I found rents and fissures in the ground, one of which I followed for about the extent of a mile. In some places they were more than an inch wide.”
Liquidification of sediments occurred in Milnerton as it did in Christchurch.
Chris Hartnady, an international expert on geotectonics and technical director of the Umvoto science consultancy in Muizenberg, wrote on the company’s website that he estimated the size of the 1809 quake to be 6.5.
The website states: “Earthquakes are a rare but a very real threat for Cape Town... increased public awareness of this hazard is needed.”
John Rogers of UCT’s geology department said the sediments surrounding Koeberg were the same as those at Christchurch. When shaken, sand grains in both sediments moved, releasing water from between them, which rose to the surface, as seen at Christchurch. This liquidification was seen at Blouberg in 1809, Rogers said.
He said because of the Milnerton fault Eskom dug out these sediments to get to hard bedrock before building Koeberg. They had then laid a 6m foundation of cement, placed pillars on this with neoprone rubbers on top to absorb vertical movement. Above that they put a metal plate designed to allow sideways movement. Koeberg was built on top.
Eskom spokesman on nuclear matters, Tony Stott, said the design would mean Koeberg could withstand an earthquake of 7. “It is designed as if the epicentre of the earthquake were right under Koeberg, although the Milnerton fault line is 8 to 9km away,” Stott said.
But geologist Nik Wullschleger believes Eskom should not be taking this risk. “(Japan) shows in the final event anything can happen, despite risk assessments.” - Cape Times
Nuclear power may be safe most of the time, but when things go wrong it tends to be catastrophic. Nuclear 'safety' is also often fudged and lied about. For an interesting read from the Independent UK -http:www.independent.co.uknewsworldasiaa-cloud-of-nuclear-mistrust-spreads-around-the-world-2242988.html Nuclear can never be described as a good option.
For those of you talking about Chernobyl, please educate yourself on what happened there. The Russians took short cuts on safety measures which is what led to the disaster. Nuclear stations like the ones at Fukushima (Boiling Water Reactor) have multiple safety features that do not even require any intervention. A full blown LEAKAGE of deadly radiation would require an act of God bigger than the tsunami. The radiation that has leaked so far is from the venting of steam to relieve pressure and contains very little radiation (as much as a CT scan). The actual core with the deadly radiation is behind 3 'containment' areas: the first contains the fuel, the second is a pressure vessel type containment and The entire “hardware” of the nuclear reactor – the pressure vessel and all pipes, pumps, coolant (water) reserves, are then encased in the third containment. The third containment is a hermetically (air tight) sealed, very thick bubble of the strongest steel. The third containment is designed, built and tested for one single purpose: To contain, indefinitely, a complete core meltdown. So, in laymans terms: even under a full meltdown, no deadly radiation will be released. The Japanese could step away from the plant RIGHT NOW and no one will die. The current efforts are aimed at making the clean-up easier.
PH1 :- Youare greatly mistaken, the fault was aknowleged to exisit in the desin of the KOEBERG plant. The Nuclear systems are on a concrete slab that floats on specially manufactured bearings. In the event of an earth quake up Richter scale 7.5 the nuclear conponents will merely vibrate alittle. As to the evacuation plans get a life you imbecile, of course they have evacuation plans they and emergency services in Cape Town practice them every year.
there are conservative plates and constructive plates not destructive plates. They are nothing to worry about. I have never heard of any sort of natural disater in south africa since I was born. Why? The answer is simple. We are aroud the atlantic ocean and the indian ocean. The pacific ocean is the dangerous ocean with the so called ring of fire
Seen it all, wrote
The major problem is that the Japanese emergency generators for the pumps got flooded because they were right next to the power station. Duh... When Katrina struck, the emergency pumps got flooded and stopped because they were below sea level. Duh... Now hopefully Koebergs emergency pumps are on a hill far away or atop 30m concrete towers. Who knows. The issue is to try and cover all your bases. Contingency planning is not the probability of it happening, but how to handle it if does happen. Having sensible mechanisms in place. All these nuclear power stations are right next to the sea. Big waves are a real probability at the shore. The control room should be elevated.. etc.
Far from being sensationalist it is important to talk of potential dangers so close to home. The public has a right to know! 1) To my knowledge, the exact location of the Milnerton fault around the Koeberg nuclear power plant is uncertain. The 1:250,000 geological map of the Cape Town area does not in fact show the fault. Urban legend has it that at the time Koeberg was planned, the fault was "erased" from the map. True or not, who knows? 2) The International Atomic Agency now suggest there be no fault capable of movement within a 8km radius of the proposed nuclear site. Whether Koeberg is 8 or 9km away is in my opinion disingenious. And are we really in a position to judge whether the Eskom spokesperson is correct to say that Koeberg was built to withstand earthquakes up to Richter scale 7, particularly if knowledge of the fault was seemingly so scant at that time? Talk is easy. 3) Nuclear power remains potentially dangerous. Questions should therefore be asked of Eskom and the authorities what the plans are to protect people in the greater Cape Town area in the event of a catastrophic accident. What are the evacuation plans, if any?
@Annoyed Physicist: One does not have to be a scientist or physicist. All one has to do is look at history. Look at what happened at Chernobyl! Look at the deformed children born to women exposed to radiation while pregnant. Look at the large area impacted (even as far as the UK). Look at the duration of the impact (up to hundreds of years). On a side note (since you were referring to coal): I would love to hear your explanation regarding global warming and global cooling in context of the history of our planet. My point being that it is a natural phenomenon, not man-made! Global warming is just another money-making excuse, just like organic food is on a much smaller scale (and as a physicist I am sure you are aware of the outcome of the scientific studies on organic food).
We should all be a bit worried... As it is Cape Town only has 3 roads in and out of town: N1, N2 and the one past Koeberg. If something should ever go wrong for whatever reason...... we in Cape Town will all be sitting ducks. And that, is a very unhealthy situation. These plants should be built very far from any major cities. It only makes sense.
These guys should be more worried about Acid Mine Drainage in Johannesburg, as opposed to an "eminent" nuclear disaster in Cape Town...talking about getting your priorities upside down
Of every comment I've read, I just love the "moon and stars provide light at night". That is a very helpful comment. Thank you your useful insight, Anonymous contestant it has been invaluable. Oddly though; and this is just a guess; I'd wager that you are partial to electricity... I mean; and I'm just guessing here: You heard about recent catastrophe's via some or other technical innovation (TVinternetsatellite)? And... you probably did use a computer and monitor to upload your brilliant insight to this forum - you didn't just beam it over with a moonbeam? So I'm thinking that you're really just bored, confused, andor talking through your blowhole
damn you Royal Ascot - and here i thought it was always me rocking my girlfriends world... apparently not so.
@Anon - 11:15 You are right. The comment also assumes that alternative and renewable energy structures would have been built 'on the beach' within reach of tsunamis, whereas the opposite is true.
Point is that Koeberg is now essentially in a residential suburb - and CT is expanding. When it is time, decommision it and build new ones far up the west coats away from cities.
It's good to see there are so many rational people to quell blind uninformed panic. I do have a question, though... how come the horoscopes, John Edwards, etc. didn't offer a specific warning. Odd that. Probably last Fiday's Tokyo Morning Herald horoscopes promised all manner of good fortune for its 12 subdivisions of humanity that morning. Not one would have suggested that swimming lessons or considering a nuclear bunker would be a good idea. Sigh... My point is - let's stick with science and rational thought.
What Michael said. and "worry more about the competence of humans running the plant than improbabilities of tectonics.
@ Hilton ... you right, they wouldnt be reporting on Koeberg and verifying its safety if it werent for Japan. but dont be ignorant. thats exactly when things often get investigated and reported in parallel. let me give you an example. after 911, airports around the world got more media coverage and things were investigated there and everywhere. and rightly so.
First comment: "Japan would be in pitch black darkness right now had there be no nuclear plants" Yes, except for when the sun shines and the moon and stars provide light at night.. which is how it was always supposed to be.
Earth quakes and tsunamis are not the issue. The issue is that with nuclear power plants, the consequences of an accident are horrendous and catastrophic. I think it's fair to say that the utilities involved in accidents the world over were all built by some very smart people, and it is foolish to think that those who built Koeberg were smarter. And then there are the operators....
So worst case scenario, Koeberg pops. First to go is Atlantis...that solves our oversupply problem.
what Hilton said.