|
17 September 2007
Sheffield scientist to reveal plutonium disposal method
A scientist from the University of Sheffield will announce today (Monday 17 September) a pioneering method of disposing safely of plutonium, the highly-dangerous, radioactive waste element used in most modern nuclear weapons.
Professor Fergus Gibb, from the University’s Department of Engineering Materials, will discuss his findings at the Materials Research Society Symposium on the Scientific Basis for Nuclear Waste Management. The event, which is being held between Sunday 16 and Friday 21 September 2007 at Sheffield City Hall, is widely regarded as the most important annual international conference on radioactive waste.
There is currently no method for the safe disposal of unwanted plutonium that is generated during the production of nuclear energy. Until now, the world’s 1800 tonnes of unwanted plutonium, which exists largely in the form of spent fuel, has been kept in interim storage, with no way of disposing of it completely. This has caused a long-term waste management problem, as well as creating a potential security threat. Only a few kilograms of plutonium are needed to make a nuclear bomb.
Professor Gibb will announce that he and a team of researchers from the University have successfully demonstrated that plutonium can be incorporated in a stable waste form and mixed with crushed granite, which is then partially melted and completely recrystallised under slow cooling conditions. This recrystallised rock can then be safely disposed of.
It had been widely believed that such recrystallisation could only be achieved through extremely slow natural cooling over hundreds, if not many thousands, of years. However, Professor Gibb will confirm that his tests have successfully melted and completely recrystallised the granite within a few months.
The method uses deep borehole technology to dispose of the plutonium-bearing granite. In conventional systems for nuclear waste disposal, the waste is buried in tunnels between 300 and 800 metres below the surface. In deep borehole technology, one of Professor Gibb’s major research topics, the granite containing the waste is deposited into vertical shafts three to five kilometres down, deep into the Earth’s crust where it is in equilibrium with the enclosing rock, thus rendering it safe to bury forever.
Professor Gibb said: “Our method of plutonium disposal is surprisingly simple. Recent advancements in drilling technology have meant that we can now go much deeper into the Earth’s crust to dispose of nuclear waste. Using these deep boreholes we at the University have created a method of safely encapsulating plutonium before burying it and disposing of it completely.”
The symposium, which has been organised by the University’s Department of Engineering Materials, gathers together experts from all over the world to discuss new methods of dealing with the growing nuclear waste problem. In a major coup for the University, it is the first time that the conference will be held in the UK and will gather together over 120 professionals to discuss various aspects of nuclear waste management.
|
