Is nuclear waste safer buried deeper underground?

At the moment, the UK plans to dispose of spent nuclear fuel and other forms of high-level waste (HLW) in relatively shallow repositories just 300 to 800 metres underground. But Professor Fergus Gibb of the Department of Engineering Materials at the University of Sheffield isn't convinced this is safe enough and is currently looking into alternative methods of disposal for these kinds of materials.

The debate on the problem of nuclear waste disposal is ongoing. The method adopted by most countries having to deal with high-level radioactive waste is geological disposal in mined and engineered repositories from 300 metres to 800 metres underground.

The problem with this method is that the material is being placed in the zone where groundwater circulates. If anything leaked out into the groundwater from the repository it could be disastrous.

"As a geologist, I'm not totally convinced that this is the best option, so my research is to find an alternative method of geological disposal which would be safer and more secure," said Professor Gibb.

Clearly, solving the problem of HLW disposal is crucial to the future of nuclear power. Professor Gibb first began work in this area in 1993 and has received funding from British Nuclear Fuels Ltd., the Engineering and Physical Sciences Research Council, Nexia Solutions and the Nuclear Decommissioning Authority.

His research has produced a number innovative concepts for both low- and high-temperature, very deep disposal of spent nuclear fuel and other forms of HLW. His work investigates the underpinning science and develops the technology for the disposal of high-level radioactive waste in very deep boreholes from three to six kilometres underground.

At these depths, there is relatively little groundwater and what there is has usually been static for millions of years, doesn't move far and won't leach out the waste material. Even if an accident took place, there would be no potentially disastrous consequences for anyone above ground.

To investigate the feasibility of very deep borehole disposal, Professor Gibb's research group is carrying out mathematical modelling of the physical environments in and around both low and high-temperature deep boreholes.

These would be for the disposal of various forms of nuclear waste, including spent fuel, reprocessing wastes and fissile materials like plutonium. The team is also looking into a range of possible materials and designs for the containers of these wastes.

"We are hoping to embark on large-scale testing of deep borehole disposal concepts," said Professor Fergus Gibb adding, "a solution for nuclear waste is not only an academic issue it is also a political issue, but technically we are optimistic."



For further information, please contact Professor Fergus Gibb at:

tel: 0114 222 3630

email : f.gibb@sheffield.ac.uk