Sweden claims nuclear waste storage safe
As Sweden debates where to store spent fuel from its nuclear reactors, scientific evidence has emerged to suggest that even if the three protective barriers that surround it are breached, there will be no radioactive contamination of groundwater.Sweden plans to protect its nuclear waste with a shell of copper reinforced with iron encased in clay and buried in surrounded by 500m of granite bedrock.
Chemical reactions that take place this deep within the earth means that, should all three barriers be breached, the interaction between the iron and groundwater would create large amounts of hydrogen which, under the naturally high pressures 500m below the surface, would prevent the uranium from dissolving.
Researcher Patrik Fors has been conducting long-term experiments on behalf of SKB, the Swedish Nuclear Fuel and Waste Management Company, and claims that these show there is no risk of contamination for tens of thousands of years, when the levels of radiation are so low they will pose no environmental threat.
"The hydrogen effect was discovered in 2000," he said.
"It's a powerful effect that was not factored in when plans for permanent storage began to be forged, and now I have shown that it's even more powerful than was previously thought."
He has carried out laboratory trials on three types of spent fuel and with all three hydrogen was shown to protect the fuel from being dissolved in the water, even though the highly radioactive fuels create a corrosive environment in the water as a result of their radiation.
The reason for the protective effect is that the hydrogen prevents the uranium from oxidizing and converting to liquid form.
The hydrogen makes the oxidized uranium that already exists as a liquid in the water shift to a solid state.
The outcome was that the amount of uranium found dissolved in the water, after experiments lasting several years, had lower than the naturally occuring levels in Swedish groundwater.
"The hydrogen effect will prevent the dissolution of nuclear fuel until the fuel's radioactivity is so low that it need no longer be considered a hazard," said Fors.