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The salt mine at Gorleben, |
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Salt domes are often seen as safe locations for the permanent storage of nuclear waste. However, recent research at Groningen University in the Netherlands has pointed out that radiation may have a catastrophic effect on the stability of these domes.
For a start, the rock salt is likely to degrade. Worse could happen at a later stage, with possible explosions and probable leakage of radiation into the environment.
Russian-born researcher Anton Victorovitz Sugonyaku is the author of the thesis about salt dome radiation hazards. He questions the feasibility of the entire concept of storing radioactive waste in these underground mountains of rock salt.
Dr Sugonyaku explains that they were formed eons ago and have never changed since. This apparent immunity to change has made them a prime candidate in the search for a safe nuclear waste storage location.
The idea is to drill a hole deep into the salt dome - we're talking hundreds of metres - and then lower containers with radioactive waste into the hole. Once enough containers have been stacked on top of each other, the hole will be filled with concrete, thus ensuring that no radiation ever escapes.
Not such a good idea after all
Until recently, this seemed to be an excellent idea. The waste would just sit deep underground forever, slowly burning off all radiation until it posed no threat anymore. The chance that future generations would accidentally stumble upon the containers were minute; they're just too deep down.
Furthermore, as salt domes were seen as among the most stable of geological formations, it seemed the perfect solution. Dr Sugonyaku's research has changed this perception.
In layman's terms, the rock salt's crystal structure loses its integrity. Then, the story gets worse:
The experiments
Conducting experiments which are supposed to mimic the exposure of rock salt to millennia of radiation will never be completely realistic. Dr Sugonyaku tried to get as close as possible, radiating salt crystals in his laboratory for several months. The radiation levels could be controlled, as well as the speed of the radiation and the temperature of the crystals.
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The Borssele nuclear power plant in the Netherlands |
All this makes the resulting data scientifically valid; the predictions stand. It leaves us with the question of whether salt domes are definitely not an option anymore when it comes to storing nuclear waste. Surprisingly, for Dr Sugonyaku, the answer is not an unequivocal 'No'.
"I think we should dig deeper, scientifically, we should search for materials that can be put in between the canisters and the natural rock salts. Natural rock salt is very sensitive to radiation, we know that, we have seen that, but we have found some materials , also sodium chloride materials, which are much less sensitive. For instance, sodium chloride doped with bromine or iodide could serve as a protective layer..."Conclusion
If salt domes are to be used as storage locations for nuclear waste, monitoring will be key. Rock salts may still be a viable option, but the original idea of just putting the waste deep into the ground and then basically forgetting about it is definitely out.
Tags: atomic, borssele, energy, gorleben, groningen, netherlands, nuclear, salt domes, sugonyaku