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Senior Fellows


Martin Metcalfe has more than 40 years’ experience working in research and development (R&D) within the nuclear industry for CEGB, Nuclear Electric, Magnox Electric, BNFL, Nexia Solutions and NNL. He has worked in the fields of reactor coolant chemistry, graphite technology, graphite core structural integrity assessment and graphite waste management. This has included active involvement in R&D, strategic development and management of R&D programmes, consultancy, expert review, and line management activities. He is internationally recognised as an expert in graphite technology, being a founder member of the International Nuclear Graphite Specialist Meetings. Martin is also an Honorary Visitor at the Materials Performance Centre, University of Manchester.

Key Areas of Expertise

Throughout his career Martin has developed considerable experience of gas-cooled reactor operation and graphite moderator behaviour, specialising in the development of graphite core safety case methodologies, graphite core monitoring and surveillance, graphite material properties and characterisation of waste graphite to support decommissioning and disposal. 

Martin has been a regular contributor to the International Nuclear Graphite Specialist Meetings, the biennial UK nuclear graphite meetings promoted by the UK nuclear regulator and is a member of the EPSRC Peer Review College. While the majority of his work is too sensitive for external publication, he has co-authored a number of external publications and presented invited papers in his specialised field.

More recently he has been involved in initiatives to sustain and develop technical expertise within NNL through the Laboratory Council and the Technical Excellence Development Programme.

A key element of Martin’s Senior Fellow role is to build on NNL's international reputation for characterisation of nuclear graphite and for understanding of graphite behaviour in nuclear plant, maintaining a high quality team of graphite specialists based primarily in the Central Laboratory and Windscale. This includes developing a strategy for graphite within NNL that aligns with the organisation's objective of maintaining key nuclear capabilities for the UK. This is being achieved through collaboration with UK universities, developing and encouraging a new generation of scientists. He is also working with other international facilities with interests in graphite, to maximise the scope and quality of the work.

Key Achievements

Martin has been involved in a number of customer-funded projects aimed at extending operating reactor lifetimes, providing insight into material ageing processes and developing options for graphite waste management. The following gives examples of the scope of the work.

  • Originator of the structural integrity assessment methodology adopted for the Magnox reactor graphite cores and principal compiler of core structural integrity assessments for most of the Magnox reactors
  • Responsible for directing the R&D programmes in support of the safety cases for the Magnox graphite cores, covering measurement technique development, component testing, component modelling, whole core modelling, oxidation modelling, thermal oxidation methods and validation of assessment methods and data
  • Devised and managed an accelerated graphite irradiation programme at the Advanced Test Reactor, Idaho National Laboratory, USA in support of Magnox reactor core lifetime extension
  • Participation in the NNL team for CARBOWASTE (irradiated graphite waste management) under the Seventh Framework Programme for Euroatom
  • Participant and contributor to IAEA Coordinated Research Programme “Treatment of Irradiated Graphite to meet Acceptance Criteria for Waste Disposal”
  • External Peer Reviewer to the US Next Generation Nuclear Plant graphite-related research programmes
  • NNL Impact Award winner for most promising new innovation (2013) for the development of a polycrystalline graphite model
  • Development of new ASTM standards for graphite specifically to address the unique requirements of the nuclear industry


Key Positions

Manager of research programmes for Magnox cores under the Industry Management Committee, chairing technical exchange meetings with the UK nuclear regulator (1995-2000).

Headed the graphite area under the Magnox Operational Support Programme and took the lead for British Nuclear Group on Magnox issues at the Graphite Technical Advisory Committee set up by the UK nuclear regulator (2000-2006).

Member of Graphite Core Committee (and predecessor committees), the peer review body for the UK gas-cooled reactor fleet (1991 to present).

NNL Senior Fellow for Graphite (2007 to present).

Chairman of ASTM Subcommittee D02F, Manufactured Carbon and Graphite Products (2014 to present).

Key Publications

The Effects of Thermal Annealing on the Mechanical Properties of PGA Graphite, M P Metcalfe and J F B Payne, “Management of Ageing Processes in Graphite Reactor Cores”, RSC Publishing 2007.

The Applicability of the Equivalent Temperature Concept for the Correlation of Graphite Dimensional Change Behaviour in Magnox Reactor Cores, M P Metcalfe and J F B Payne, “Securing the Safe Performance of Graphite Reactor Cores”, RSC Publishing 2010.

Break-up Testing of Waste-form Materials, M P Metcalfe, W Koch and G Turner, Mineralogical Magazine, December 2012, Vol. 76(8), pp. 2975–2983.

EU Carbowaste project:  Development of a toolbox for graphite waste management, M P Metcalfe, A W Banford , H Eccles  and S Norris, Journal of Nuclear Materials, Vol. 436, Issues 1–3, May 2013, pp. 158–166.

Evaluation of Instantaneous Coefficient of Thermal Expansion of PGA Graphite, M P Metcalfe and J F B Payne, “Modelling and Measuring Reactor Core Graphite Properties and Performance”, RSC Publishing 2013.

The Effect of Test Specimen Size on Graphite Strength, M P Metcalfe, N Tzelepi and D Wilde, ASTM Selected Technical Publications, STP-2013-01223.

Radiocarbon Mass Balance for a Magnox Nuclear Power Station, M P Metcalfe and R W Mills, Annals of Nuclear Energy 75 (2015) 665–671.