Bury nuclear waste down a very deep hole, say UK scientists
Deep borehole disposal of high level nuclear waste
Scientists at the University of Sheffield calculate that all of the UK's high level nuclear waste from spent fuel reprocessing could be disposed of in just six boreholes 5km deep, fitting within a site no larger than a football pitch.
The concept - called deep borehole disposal - has been developed primarily in the UK but is likely to see its first field trials in the USA next year. If the trials are successful, the USA hopes to dispose of its 'hottest' and most radioactive waste - left over from plutonium production and currently stored at Hanford in Washington State - in a deep borehole.
Professor Fergus Gibb, of the University of Sheffield's Faculty of Engineering, explains: "Deep borehole disposal is particularly suitable for high level nuclear waste, such as spent fuel, where high levels of radioactivity and heat make other alternatives very difficult. Much of the drilling expertise and equipment to create the boreholes already exists in the oil and gas and geothermal industries. A demonstration borehole - such as is planned in the US - is what is now needed to move this technology forward."
Fundamental to the success of deep borehole disposal is the ability to seal the hole completely to prevent radionuclides getting back up to the surface. Professor Gibb has designed a method to do this: to melt a layer of granite over the waste, which will re-solidify to have the same properties as natural rock.
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