One of the main objectives of EFDA during FP7 is to further develop and maintain a focused R&D programme in Europe, aiming at the realization of fusion power. The emphasis is on the preparation for the operation and exploitation of ITER and on the establishment of a physics base for DEMO. To this end EFDA will coordinate a range of activities to be carried out by the Associations both in physics and technology. The implementation of these activities will benefit from existing and new structures, such as the Task Forces and Topical Groups.

Topical Groups and Task Forces

The European Task Forces on Plasma Wall Interaction (PWI) and on Integrated Tokamak Modelling (ITM) set up respectively in 2002 and 2003 will continue their activities under the new EFDA, addressing key research areas.

To strengthen the co-ordination in other key areas five Topical Groups have been recently set up: on Fusion Materials Development, Diagnostics, Heating and Current Drive, Transport and MHD.

The role of these newly formed Topical Groups is to develop well-informed and synthetic scientific views on their subject. The Topical Groups will assist the EFDA Leader in the elaboration of the EFDA work programme, providing focus on subjects of particular importance, identifying specific issues and high priority research objectives which need to be addressed and proposing ways to address these issues. The Topical Groups will naturally serve as forums to compare the results obtained in various conditions, assess the relative merits of different approaches and promote new developments.

The Fusion Materials Development Topical Group is presented here. The other Topical Groups will be presented in the next issues of Fusion News.

Fusion Materials Development Topical Group

An ambitious programme on materials is one of the main keys to the successful development of fusion. Indeed one of the attractive features of fusion stems from the fact that no radioactive products result from the reaction itself: the fusion of deuterium and tritium produces helium and neutrons. However, these neutrons are very energetic: their 14 MeV energy is typically one order of magnitude higher than that of neutrons produced in fission reactors. This results in the production of a significant amount of helium in the bulk of the materials which can result in swelling and alteration of the mechanical properties.

Prof. Sergei Dudarev is working at UKAEA Culham Laboratory as a Senior Principal Scientific Officer and the Leader of Materials Modelling Group at the Theory and Modelling Department, and he is also a Visiting Professor at the Department of Physics, Imperial College London and a Senior Research Fellow of Linacre College, Oxford.

He graduated from Moscow Institute of Engineering Physics with a degree in Theoretical Nuclear Physics in 1983, and subsequently gained PhD and DSc degrees at that institute.

Prof. Dudarev’s career progressed at Oxford from 1992 to 1999. He joined the UKAEA Association in the same year and has been working there since then. Prior to his appointment to the co-chairmanship of the Fusion Materials Topical Group, Prof. Dudarev had been the Scientific Coordinator of the EFDA Fusion Materials Modelling Programme, acting in this capacity since 2006. He is the author of more than 120 papers published in refereed journals, and a book on High-Energy Electron Diffraction and Microscopy published by the Oxford University Press in 2004.

The question of materials is therefore both an opportunity and a challenge for fusion. The fact that there is freedom to chose and optimise the materials surrounding the plasma in order to minimise activation (and thereby avoid creating long live radioactive waste) constitutes indeed an opportunity. However, the specificity of the reactions produced by the 14 MeV neutrons together with the operating conditions required for the materials (large power fluxes and operating temperatures in the range 400 to 600 Celsius) constitute a challenge which fusion materials R&D has to take up.

The Fusion Materials activity under EDFA will concentrate on long term developments in connection with DEMO design studies (DEMO is the future fusion demonstration reactor foreseen after ITER): e.g. new materials, research areas with high risk, physical understanding to master the evolution of materials properties during operation. These activities will complement the project-oriented developments of Fusion for Energy (see other articles in this issue) and will therefore be prepared and executed in close cooperation with F4E. Whenever developments within EFDA will have reached an appropriate stage of maturity, an assessment will be made in view of a possible transfer to F4E.

The R&D activities address 3 main research objectives:

1. Materials development closely linked with DEMO design

EFDA activities here will focus on materials for DEMO applications. In particular the area of structural materials, functional materials, and advanced joining technology will be addressed.

2. Modelling of radiation effects and experimental validation

A reliable prediction of radiation effects necessitates a good understanding and modelling of the physical mechanisms. This requires the use and development of modelling tools and their experimental validation at the relevant scale. Some of the modelling tools need intensive computation capability and are considered in the definition of future fusion computing centres presently under discussion.

The quality of understanding and the reliability of the predictive capability based on computational material science strongly depends on experimental validation. This requires using well defined materials and irradiation conditions and conducting physical, chemical and mechanical characterisation at the relevant scale. Fission neutron and spallation-neutron mixed spectrum irradiations will be used for exploring the evolution of mechanical properties and microstructures

3. Irradiations

Irradiation campaigns are also required to constitute an engineering database of materials in real operational conditions. The irradiations will be carried out on fission reactors, spallation sources, multiple beam irradiation facilities and on the future International Fusion Materials Irradiation Facility (IFMIF) projected in the mid-term. Postirradiation examination will include the measurement of physical and mechanical properties, the characterisation of microstructure, He & H retention measurements.

Dr. Michael Rieth has been a Senior Scientist at the Institute of Materials Research I (IMF I) in Forschungszentrum Karlsruhe (FZK) since 2002. He gives also lectures in materials science at the University of Karlsruhe and at the University of Cooperative Education, Karlsruhe. Dr. Rieth is a Workpackage Leader within the European Project GETMAT dealing with metallurgical and mechanical behaviors. His main scientific interests are in materials development for advanced fusion reactor applications as well as in atomistic modelling of metallic materials and nanosystems.

He received his Master of Science degree in electrical engineering from the University of Karlsruhe in 1991 and his doctoral degree in physics from the University of Patras in 2001. He worked as a researcher at the Institute of Materials Research II, FZK, from 1995 to 1999 and at the Engineering Science Department of the University of Patras, Greece, from 1999 to 2000.

Dr. Rieth was the e d i t o r- i n – chief of the Journal of Computational and Theoretical Nanoscience from 2004 to 2005. He is the author of Nano-Engineering in Science and Technology (World Scientific, Singapore, 2003) and he is editor of the Handbook of Theoretical and Computational Nanotechnology (American Scientific Publishers, Stevenson Ranch, 2006). He has further published patents, book chapters, and numerous research articles in refereed journals.


To achieve these objectives three Research Projects and one Research Area have been set up (the Research Projects have well defined objectives, deliverables and milestones, while the Research Area presently requires only looser coordination) :

The Research Projects are as follows :

• Tungsten and tungsten-alloy development for plasma facing components, structural application, heat sink and armour materials

• Nano-structured oxide dispersion strengthened (ODS) ferritic steel (where oxide clusters have dimensions in the nanometer range) development

• Radiation effects modelling and experimental validation

The Research Area will deal with the development of SiCfSiC (silicon carbide composite made of SiC fibres embedded in SiC matrix) and associated joinings & coatings for fusion reactors.

The co-chairs of the Fusion Materials Development Topical Group are Prof. Sergei Dudarev and Dr. Michael Rieth.