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Pebbles packed with punch
Forward-thinking technology being hailed as a possible solution for Eskom's power woes.
The company remains bound by constrictions, which are preventing it from building its first demonstration model reactor, as it continues to await the approval of an environmental impact assessment and nuclear licence, a process which was started in 2000. CEO, Jaco Kriek, and Tom Ferreira, corporate communication manager for PBMR, tells Laura Cornish about SA's leading position in fourth generation nuclear reactors - a technology for which the world is still waiting.
The first high temperature commercial demonstration pebble reactor is due to commence with construction in 2010, should the environmental assessment and nuclear licence be awarded prior to this.
It will be built at the Koeberg nuclear power station site near Cape Town, and will contribute 165MW of additional electricity. Koeberg consists of two conventional nuclear reactors, each generating 930MW of energy, meaning it will require six pebble bed reactors to generate approximately the same capacity as one Koeberg reactor.
The PBMR pebbles (fuel sources) will be manufactured at Pelindaba, where fuel for Koeberg used to be manufactured until the late nineties.
Although the pebble bed nuclear concept was first started in Germany in the 1960s, South Africa will be the first country in the world to construct and run a commercial pebble bed modular reactor. "The world is looking at PBMR with great interest," Ferreira emphasises.
Ferreira predicts that the first reactor will be running by 2014, later than initially anticipated, but, contrary to assumptions, it will be competitively priced to run, construct, and maintain.
Ferreira believes that - per megawatt installed - the cost of the PBMR commercial reactors will be competitive with conventional nuclear energy, which could cost up to R120m (the PBMR demonstration reactor project costs will be in the order of R16bn).
The construction phase of the project is subject to approval from the Department of Minerals and Energy (DME) and the Department of Environmental Affairs and Tourism (Deat).
Eskom has however already signed a letter of intent with PBMR to build between 24 and 30 reactors between 2016 and 2024, should the first demonstration model at Koeberg be successful.
"Although this clean energy source will be used for many applications, half of our initial portfolio will be electricity generation," says Kriek.
Ferreira explains that one pebble, slightly smaller in size than a tennis ball, can supply electricity to a household of four for about one year. There will be 450 000 pebbles in an entire pebble bed plant.
"The benefits of the new generation technology are abundant," Ferreira continues. Conventional nuclear plants are required to be shut down every 18 months for six weeks for re-fuelling, whereas PBMRs will only require one shut-down every six years for maintenance purposes.
Fourth generation nuclear technology also has inherently safe features, automatically shutting down if the temperature becomes too hot. For this reason, no engineered safety systems are required. Core melt, or Chernobyl-type accidents, are impossible, Ferreira explains.
A pebble bed plant will also be able to ramp up its capacity during peak hours, and ramp down during off-peak.
Because of its inherent safe characteristics and the fact that single reactors are relatively small in size, residential areas can be positioned as close as 400m from such a reactor.
Next to its ability to contribute towards increasing electricity demands, the pebble bed reactor also has little adverse impact on the environment, releasing no carbon dioxide into the atmosphere.
And although anti-nuclear activists continue to claim that pebble bed reactors are health hazards, numerous specialised studies showed that nuclear plants have an insignificant impact on people's health.
One pebble will contain 9g of enriched uranium, which PBMR will import from Russia. The government is, however, looking at re-starting a uranium enrichment programme.
Pebble bed reactors can also be used for desalination, and have the ability to generate hydrogen, which experts have identified as tomorrow's fuel. In Sasol's drive to reduce its own carbon footprint, the company is looking at substituting its boilers with pebble beds.
"Little old South Africa is kicking our butt with its development of the PBMR. This should be a wake-up call for the US," says Syd Ball, senior researcher for America's Oak Ridge National Laboratory. PBMR has a workforce of 700 in this country - with the largest nuclear design team in the world, as well as 1000 people at universities, private companies and research institutes in SA and abroad who are involved with the project.
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