Materials scientists and engineers from six UK universities are joining forces to forecast the life expectancy of nuclear power reactors.
Researchers from the University of Leeds have teamed up with colleagues from the Universities of Manchester, Nottingham, Salford, Sussex and Huddersfield to examine how daily radiation exposure gradually damages the graphite blocks that sustain nuclear chain reactions.
Their findings should allow the nuclear utility companies that run the UK's existing fleet of nuclear reactors to plan for the future. The work should also show whether the next generation of very high temperature reactors, which are expected to become an important source of clean hydrogen-based power, will last as long as expected.
Graphite is a key component of most working nuclear reactors in the UK and for the most exciting designs of new high temperature reactors. The graphite blocks act as a brake for high-speed neutrons, slowing them down to speeds that are most effective for nuclear fission.
Not surprisingly, the daily neutron bombardment takes its toll on these graphite 'moderators'. The clusters of linked carbon atoms - or crystallites – that make up the graphite change their shape and the blocks become more porous. Knowing exactly how the material changes and over what timescale will help engineers predict how long the moderators can do their job properly, how manufacturing processes could be improved and how some of the damage to the graphite blocks might be reversed.
"We know so much more now about the layered structure of graphite than we did in the 1960s and 1970s when researchers started to study its material properties. Radiation damage may cause these hexagonal carbon nets to buckle or fold and this is something that we will have to take into account," said materials scientist Dr Aidan Westwood who, together with Dr Andrew Scott, is leading the work at the University of Leeds.
Researchers at each of the partner universities will be using a variety of experimental and simulation techniques to study irradiated graphite at a number of different length scales. These will include transmission electron microscopy, Raman and electron spectroscopy and X-ray tomography. The results will be pooled and used to develop computer models that can predict the behaviour of entire components under likely operating conditions.
"A multiscale approach is essential," said Dr Andrew Scott. "The distance between two carbon atoms in a graphite layer is about one seventh of a nanometer, whereas the length of a typical graphite block is one metre. We need to build up a complete picture, starting from what the neutrons do to individual atoms, to the layers of linked atoms, to the crystallites of interlocked layers, and finally to the component as a whole."
"The equipment we now have at our disposal is far more powerful than the microscopes that researchers have previously used to study these materials," said Professor Rik Brydson, a co-investigator on the project. "We will be using state-of-the-art techniques to image the layers of graphite in atomic detail."
The project, which will run for three years, is being funded by a £1.3 million grant from the Engineering and Physical Sciences Research Council (EPSRC). It will involve around 25 academics, postdoctoral researchers and postgraduate students across the six universities and key industrial partners from the nuclear industry.
"There has been very little focus on this type of nuclear research in the UK for 40 to 50 years," Dr Scott commented. "It is vital that we start training-up a new generation of nuclear engineers. This project will go some way towards doing that."
For further information: Paula Gould, University of Leeds press office: Tel +44 113 343 8059, email p.a.gould@leeds.ac.uk
Notes for Editors
1. The 2008 Research Assessment Exercise showed the University of Leeds to be the UK's eighth biggest research powerhouse. The University is one of the largest higher education institutions in the UK and a member of the Russell Group of research-intensive universities. The University's vision is to secure a place among the world's top 50 by 2015. www.leeds.ac.uk
2. The Engineering and Physical Sciences Research Council (EPSRC) is the UK's main agency for funding research in engineering and the physical sciences. The EPSRC invests around £850 million a year in research and postgraduate training, to help the nation handle the next generation of technological change. The areas covered range from information technology to structural engineering, and mathematics to materials science.
3. The University of Manchester, a member of the Russell Group, is the largest single-site university in the UK. It has 22 academic schools and hundreds of specialist research groups undertaking pioneering multi-disciplinary teaching and research of worldwide significance. According to the results of the 2008 Research Assessment Exercise, The University of Manchester is now one of the country's major research universities, rated third in the UK in terms of 'research power'. The University has an annual income of £788 million and attracted £253 million in external research funding in 2007/08.
4. The University of Nottingham, described by The Sunday Times University Guide 2011 as 'the embodiment of the modern international university', has award-winning campuses in the United Kingdom, China and Malaysia. It is ranked in the UK's Top 10 and the World's Top 75 universities by the Shanghai Jiao Tong (SJTU) and the QS World University Rankings. It was named 'Europe's greenest university' in the UI GreenMetric World University Ranking, a league table of the world's most environmentally-friendly higher education institutions, which ranked Nottingham second in the world overall. The University is committed to providing a truly international education for its 40,000 students, producing world-leading research and benefiting the communities around its campuses in the UK and Asia.
More than 90 per cent of research at The University of Nottingham is of international quality, according to the most recent Research Assessment Exercise, with almost 60 per cent of all research defined as 'world-leading' or 'internationally excellent'. Research Fortnight analysis of RAE 2008 ranked the University 7th in the UK by research power. The University's vision is to be recognised around the world for its signature contributions, especially in global food security, energy & sustainability, and health.
5. The University of Salford is home to almost 20,000 students and over 2,500 employees on a green campus only a mile and a half from Manchester city centre. It offers an exceptional learning environment for students, with strong opportunities in research and enterprise and plays a key role in connecting with, and regenerating local communities. From 2011 the University will have a presence at the MediaCityUK development at Salford Quays. Staff and students from all areas of the University will make use of this cutting-edge facility, located at the heart of six major BBC departments. *One of the project partners at the University of Salford has since moved to the University of Huddersfield.
6. The University of Sussex was the first of the new wave of universities, receiving its Royal Charter in August 1961. In the 2010 Times Higher Education World University Rankings, Sussex is ranked 8th in the UK, 16th in Europe and 79th in the world, setting it alongside some of the world's most prestigious institutions. Sussex is a leading research university, as reflected in the 2008 Research Assessment Exercise. Over 90 per cent of Sussex research activity was rated as world leading, internationally excellent or internationally recognized.