New research consortium: Testing materials for fusion power plants

Inside a fusion reactor, materials are simultaneously exposed to extreme temperatures, mechanical stress, and intense particle radiation. This alters the crystal lattice, creates defects and pores, and can cause material failure. Affected materials include ferritic steels such as EUROFER97, tungsten and tungsten alloys for the reactor inner wall, as well as copper alloys for cooling components. Under neutron bombardment, rhenium also forms in tungsten -- a change that affects the material properties.

This is where FUMA comes in, the “Competence Center for the Optimization of Fusion Materials.” It brings together one positron research group and three neutron research groups from FRM II, as well as two IPP groups whose methods complement one another. One group is investigating additively manufactured components and welded joints, while another is analyzing pores and internal stresses under industry-relevant conditions. “With our positron spectroscopy at FRM II, we want to understand material damage at the atomic level,” explains project coordinator Prof. Christoph Hugenschmidt of TUM. “Using the antiparticles of electrons, we can trace how the smallest defects develop into larger structures that ultimately determine the service life of a material.” Prof. Christian Pfleiderer, Scientific Director at FRM II, adds: “The neutron methods used at FRM II provide unique insights into the structure of fusion materials, from the atomic scale to the millimeter scale.”

Hugenschmidt explains why Garching offers ideal conditions for the project: “Here on site, IPP contributes outstanding expertise on materials and components for a future fusion reactor.” In addition, the site offers unique experimental capabilities: heat loads of up to 20 megawatts per square meter, as well as targeted material damage caused by neutron irradiation, can be studied under realistic conditions.

The long-term goal is to be able to reliably predict the service life of materials in a fusion reactor. The groups are jointly developing a measurement program: IPP defines the research priorities for materials-related questions and prepares samples, while the analysis groups at FRM II continue to improve their neutron- and positron-based instruments and investigate the damage mechanisms.

Further information:

• As part of its High-Tech Agenda Germany, BMFTR is funding the three-year “FUMA” project with around 3.6 million euros.
• On the Technical University of Munich (TUM) side, the project involves Prof. Christoph Hugenschmidt (Physics with Positrons, NEPOMUC), Dr. habil. Ralph Gilles (Advanced Materials), Dr. Michael Hofmann (Residual Stresses, Textures, Phase Transitions), and Dr. Tobias Neuwirth (Neutron Radiography and Tomography).
• From the Max Planck Institute for Plasma Physics (IPP), the participating researchers are Prof. Rudolf Neu and Prof. Jeong-Ha You (both Plasma Edge and Wall -- Plasma Component Interaction), as well as Dr. Thomas Schwarz-Selinger (Plasma Edge and Wall -- Ion Beam Analysis and Modification).

Scientific contacts:

Prof. Dr. Christoph Hugenschmidt 
Technical University of Munich
Heinz Maier-Leibnitz Research Neutron Source (FRM II) 
+49 89 289 14609 
christoph.hugenschmidt@frm2.tum.de

Prof. Dr. Rudolf Neu 
Max Planck Institute for Plasma Physics
+49 89 3299 1899 
rudolf.neu@ipp.mpg.de

Media contact:

Andrea Voit
Kommunikationsmanagerin
Technical University of Munich
Heinz Maier-Leibnitz Research Neutron Source (FRM II) 
+49 89 289-12141
andrea.voit@frm2.tum.de