Nuclear energy currently provides 20% of the UKs energy and this is expected to increase as further significant funding has been earmarked to develop new nuclear power facilities. A key challenge faced by the nuclear industry is how to condition and dispose of radioactive waste safely and securely. Legacy, current, and planned UK nuclear facilities will generate 450,000 m3 of radioactive waste by the end of the century - enough to fill Wembley Stadium. At present most radioactive waste is encapsulated in cement. A new research partnership between the University of Sheffield, Sellafield Ltd., the Nuclear Decommissioning Authority (NDA), and the UK National Nuclear Laboratory, is seeking to address some of the challenges of nuclear waste encapsulation by looking at new cement technologies to provide safe and reliable disposal solutions.
The cement industry is currently investigating blended Portland cements incorporating calcined clays - specifically limestone calcined clay cement (LC3) - as it strives to reach ‘Net Zero’. LC3 is a promising new type of cement which offers a more environmentally friendly alternative to traditional Portland cement. This is because there is reduced CO2 emissions during production, and LC3 is produced using naturally abundant limestone and clay materials, and so is capable of meeting the immense scale of demand for cement and concrete.
The advantages of LC3 extend beyond the environmental benefits with potential applications in nuclear waste encapsulation. The University of Sheffield, and Sellafield Ltd. along with NDA and the UK National Nuclear Laboratory, have partnered on a new £1M project that will explore how different characteristics and amounts of calcined clays can be used to produce the best performing cements for encapsulating nuclear waste. This research forms groundwork for using this new material for encapsulating and safely storing and disposing of nuclear waste, and will help us understand how it behaves. It will support future development and implementation at Sellafield Ltd., thus ensuring safe and reliable conditioning and disposal of UK nuclear waste.
Dr Brant Walkley, Senior Lecturer and Head of the Sustainable Materials at Sheffield research team, said: “The researchers at Sheffield are experts in cement chemistry and engineering as relevant to the nuclear sector, while the Centre of Expertise for Cement and Process, led by Dr Stephen Farris at Sellafield Ltd., are experts in industrially-focused research, development, and implementation of cement encapsulants to condition complex waste streams.
This partnership will enhance our overall programme of work focused on development of new cement technologies for the nuclear sector, and will enable our cross-sector team based at both the University of Sheffield and Sellafield Ltd. to further strengthen its position as a global leader in cement science and engineering.”