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How the truth begins to emerge – here we get on the record info on how the “safe” PBMR generates significantly more waste than conventional reactors + how difficult the graphite problem is to deal with DESPITE all the hogwash put out in EIAs the public were expected to plough through!!!! This same university also back-tracked some years ago after being called in to monitor excessive radioactivity on the Crocodile River (next to Pelindaba) after thousands of birds and fish deaths were recorded by a Fauna and Flora official. The university later said it had “over-estimated” the issue, despite readings being higher than recordable on it’s Geiger counter! >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Microscopic power of Nuclear Waste 28 September 2007, Financial Mail |
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The creation of quantities of long-lived radioactive waste is the most formidable problem facing the nuclear power industry today.
Now a team at the University of Pretoria (UP) is working on a solution that harnesses Mother Nature herself to minimise radioactive waste created in the pebble bed nuclear reactor system. Rather than using existing physical-chemical processes to break down the waste – which can generate more waste – professor of chemical engineering at UP, Evans Chirwa, is working on a solution that relies on natural processes using bacteria or other microbial processes to break down the radionuclides. “Micro-organisms have evolved mechanisms for survival in hostile environments over billions of years,” says Chirwa. “They can withstand 5 000 times more radiation than humans.” These tiny organisms are already being used to reduce toxic metals in the environment. For instance, they have been used to detoxify chromium, uranium and mercury. Scientists have also recently identified micro-organisms capable of using ionising radiation as an energy source. Chirwa’s team is specifically focused on SA’s pebble bed modular reactor because though the system design is believed to be inherently safe, its design produces considerably more waste than conventional reactors. Central to the design (and the safety) are the “pebbles” – the graphite-encased uranium particles that drive the reaction. Though the graphite prevents the release of any of the fission products generated during operation, the graphite matrix becomes contaminated in the process. “Some of the carbon changes to a radioactive form of carbon, known as carbon 14,” says Chirwa. The problem is that graphite is not that easy to treat - uranium and other metals are easier. But Chirwa believes they have a possible solution. They plan to use living cells to separate carbon 14 from carbon 12 and 13. (C12 is the most abundant of the three isotopes that make up carbon, accounting for 98% of it.) “Separation of carbon 14 is a new proposal. If we can remove the C14, then we can process it and use it for medical purposes as a radionuclide.” The remaining graphite would be reconstituted back into pebbles. ???? But the answers won’t be available soon. “We have had some results but they need to be verified scientifically.” The initial proof of concept will take a year, after which the team will develop the full experiment. “It may be a slow process,” says Chirwa, “but it is important – the waste issue is retarding the development of the reactor.” |
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