Glass: Using ancient technology to solve modern challenges
Glass is one of the oldest man-made materials - it can remain stable for thousands of years and has the ability to incorporate radioactive elements within its structure. Research at Sheffield looks to understand how these properties can be used to safely immobilise waste from nuclear power plants.
Glass offers some key advantages for immobilising nuclear waste. The flexible structure of glass allows it to chemically incorporate a wide range of elements, including many of the radioactive isotopes found in nuclear waste. Glass, especially borosilicate glass, is very durable and resistant to corrosion; it can withstand exposure to water and even other chemicals with little risk of the radioactive materials leaching out. Compared to some other materials used for nuclear waste immobilisation, glass is cost-effective and relatively easy to process, as it can be melted and poured into containers for storage and disposal.
Research at Sheffield
Dr. Clare Thorpe's overarching research aim is to understand the behaviour of materials, and particularly glasses, in complex natural environments. Understanding material-solution interactions in these systems requires an interdisciplinary approach involving aqueous geochemistry, solid state chemistry, metal redox cycling, geomicrobiology, mineralogy, and glass chemistry. To achieve this Dr. Thorpe combines laboratory experiments with the study of glasses that have been altered in natural environments where their burial time and conditions are known, these include glasses from shipwrecks, the foundations of buildings and purposely designed field experiments.
Researchers and students in the group are studying the corrosion of nuclear glass generated by the Manhattan Project (USA), the UK's fleet of civil nuclear power stations and even possible future vitrified wastes yet to be produced. Projects investigate the effect of deep saline groundwaters, the corroding steel canister and even microorganisms on the rate of radionuclide release from the glass matrix.
Glass has been manufactured for thousands of years but we still don’t have a reliable way to predict its long term behaviour, there are just so many variables.”
Dr Clare Thorpe
Lecturer in Radioactive Materials, School of Chemical, Materials and Biological Engineering
The Ballidon experiment was established by Sheffield based glass scientists and archaeologists in 1970. Its purpose was to compare the corrosion of modern and ancient glasses and it was intended to run for over 500 years. The experiment has since been expanded to study glasses of a type used, in the UK and other countries, to immobilise radioactive wastes.
In this short film, Archaeology and Materials Science and Engineering researchers unearth the latest set of glass samples from the Ballidon burial mound. These samples will be studied to see what their alteration can tell us about the long term durability of glasses designed to keep radioactive elements locked away for tens of thousands of years.
