Q&A – Andrew Sherry

Materials World magazine
3 Oct 2015

Rhiannon Garth Jones talks to Professor Andrew Sherry, Chief Science and Technology Officer at the UK National Nuclear Laboratory, about current nuclear challenges in the UK.

How did you get into the industry? 

I read Metallurgy at the University of Manchester and went on to do a PhD on the fracture mechanisms in single crystal turbine blade materials with Rolls-Royce. I joined the United Kingdom Atomic Energy Authority in 1987 for two reasons. Firstly, the job I was offered built on my PhD studies but took me into a new area – understanding irradiation effects on the fracture properties of ferritic pressure vessel steels. Secondly, it was the first job I was offered! 

What has been your most exciting experience working within the nuclear industry? 

I would have to give two answers. Firstly, when leading the Dalton Nuclear Institute at the University of Manchester, I was able to work with colleagues to design and build a new research centre focused on understanding radiation effects on materials and chemistry. The Dalton Cumbrian Facility opened in 2011 and is now a thriving base for the UK research community. This is part of the UK building the research infrastructure it needs to enable the nuclear community to engage in leading edge research with international colleagues.

Secondly, following the Fukushima nuclear accident, I was involved alongside a number of other nuclear academics in speaking with the media – answering questions regarding what was happening during the incident and its likely impact. I spent 2-3 weeks answering ‘yes’ every time I was offered the opportunity to speak to the media. This showed me the importance of the relationship between the scientific community and the media, and the value the independent nuclear sector has in helping to engage the public on nuclear matters. 

What is it that you’re working on now?

I have three main roles. Firstly, as Chief Scientist for the National Nuclear Laboratory (NNL) I am leading the growth of nuclear R&D within NNL, including links with our customer base, as well as delivering innovation in nuclear programmes, including decommissioning, and fostering connections with our academic colleagues to bring new skills and new knowledge into the sector. 

Secondly, I am involved in a number of Government committees, including the Nuclear Industry Council, where I lead the work stream on public engagement in nuclear energy. 

Thirdly, I remain a professor at Manchester, where I continue to lead research into materials fracture and structural integrity.

What do you think are the main materials challenges in the nuclear sector currently? 

Materials are fundamental to all engineering sectors, and the nuclear sector is no different. The materials challenges associated with the UK operation of advanced of advanced gas-cooled reactors (AGRs) relate to the influence of the operating environment on the integrity of the graphite core and the non stress-relieved stainless steel welds within the boilers. These same materials challenges are also relevant to advanced Generation IV reactors, which are not yet built, such as the sodium-cooled fast reactor and the high temperature gas-cooled reactor. The UK can therefore bring its expertise and experience to make a real contribution to these international research projects. 

For the next generation of reactors, some other materials challenges relate to improved manufacturing technologies including the hot isostatic pressing (HIP) of large scale components, and the development of improved welding technologies, such as laser and electron-beam welding of stainless steel and ferritic components. The Nuclear Advanced Manufacturing Research Centre at the University of Sheffield is pioneering the development of these techniques.

For fuels, the drive is to create ‘accident-tolerant fuels’ through the development of new fuel materials and advanced cladding or coating materials able to withstand the high core temperatures during an accident – such as happened in Fukushima – to reduce the possibility of core melt. The new Nuclear Fuels Centre of Excellence, jointly hosted by NNL and the University of Manchester, is leading research in these areas.

People are starting to look now at whether advanced 3D printing technology could be used to make components – and maybe even fuel – to the very tight specifications and tolerances needed for nuclear reactor use.

What is needed to address these challenges?  

Essentially, three things are required for the UK to be recognised as a ‘top table’ nuclear nation. Firstly, the UK needs programmes to address materials issues. The Research Councils have developed a strong materials programme within their nuclear portfolio at low technology readiness levels (TRLs), but this funding does not extend to the development and prototyping of new materials technology at higher TRLs. The Nuclear Innovation Research Advisory Board is making recommendations to Government for R&D programmes at higher TRLs that will enable the UK to grow its contribution to its own domestic nuclear programmes and to increase its international engagement.

Secondly, the UK requires the experimental and computational facilities needed to undertake the research. The new National Nuclear Users Facility is creating a suite of open access research facilities that will enable the UK research community to use state-of-the-art facilities to deliver these nuclear programmes. The UK also has previously established large-scale nuclear R&D facilities including internationally leading facilities to handle highly radioactive materials. These facilities must be fully commissioned to provide the capacity to undertake the R&D required.

Finally, the UK needs the people to lead the R&D programmes into the future. The existing nuclear community is ageing, and subject matter experts are retiring. It is now critically important to use R&D programmes to transfer the knowledge from the senior experts to the next generation, so that the UK’s leading knowledge of materials in nuclear environments is not lost. R&D programmes are perhaps the most effective way to do this.

Do the flaws in the reactor pressure vessel of EDF’s first EPR, in France, and the recent defects found in two Belgian nuclear reactors have any implications for the UK’s Hinkley Point C and current nuclear fleet? 

The ‘flaws’ identified in the reactor pressure vessel head were not flaws at all. Rather, some regions within the forging contained a slightly higher carbon content than the specification allows – 0.3% carbon, with a 0.22% maximum allowable. The significance of this is that a high carbon content can reduce the fracture resistance of the steel, and since the RPV is an ‘incredibility of failure’ component (a failure probability of 10-7 per reactor year must be demonstrated), such an impact on fracture properties could be significant. The EPR build that is planned at Hinkley Point C, however, will apply the lessons from the experience in France and Belgium, and have a considerable programme of materials testing and examination that the UK nuclear safety regulators will review.

What do you think is the future of nuclear in the UK? 

The combined challenge of reducing UK carbon emissions while maintaining a secure supply of affordable energy has led many to view nuclear as a key component of the UK energy mix, alongside renewables and future carbon capture and storage. The current estimates of future nuclear generating capacity needs in the UK range from simply replacing the existing 12GWe to putting the UK on a par with the current French generating capacity of more than 60GWe. There is an opportunity to develop nuclear technologies that enable the intermittent renewable technologies to integrate effectively alongside each other. This may mean the need for some nuclear power stations to load-follow in the future, rather than to all operate in a static baseload capacity.

What is your biggest concern about the current nuclear industry? 

The nuclear workforce is ageing. Studies by Cogent, the sector skills council, show that within a decade more than 50% of the existing nuclear workforce will retire, including most of the subject matter experts who have built up decades of experience in the sector and are internationally renowned. The Nuclear Industry Council has highlighted such high level nuclear skills as one of its major priorities and has recently published a new strategy to regenerate this expertise, but this will take time and commitment on behalf of the sector.

The nuclear sector represents a major growth opportunity for the UK at a time when low carbon, secure and affordable energy is fundamentally important both nationally and internationally. The UK has decades of experience across the full nuclear lifecycle including design, manufacture, construction, operation, decommissioning and waste management to make a major contribution to nuclear programmes both at home and overseas. It is vital that we continue to grow the programmes, the facilities and the skills for this sector to thrive in the 21st Century