The Nuclear Fusion Programme bundles the activities of the Forschungszentrum Karlsruhe which are related to the development of technologies for a fusion reactor. These activities under the contract of Association between EURATOM and Forschungszentrum Karlsruhe are carried out within the framework of the European Fusion Development Agreement. Fusion energy is associated with the wish to supply a safe and environmentally compatible source of energy that decisively contributes to the supply of mankind's electricity consumption for the next centuries.

The Institute for Materials Research (www.fzk.de/imf) is involved in the development and qualification of materials as well for highly loaded plasma-facing components of the DEMO plant and for the supporting structure of the components. The development aims at high-performance materials that allow for high operational temperatures and coolant pressures under the impact of high-energy neutrons. In addition, the materials should be low activating under neutrons in order to maintain the environmental attractiveness of fusion plants.

Structural materials such as EUROFER 97, for commercial fusion reactors with expected plant lifetimes of about 30 full power years, must allow for higher operational temperatures and coolant pressures and should also withstand high neutron fluences that cause material damage such as hardening, embrittlement, dimensional instability etc.

In addition to standard tests the Forschungszentrum Karlsruhe is investigating the concept of characterisation of irradiated material by instrumented indentation. For this reason they purchased a ZHU0.2/Z2.5 modular testing system from the Zwick Roell Group (www.zwick.com) to assist them in their quest to investigate the material's mechanical properties after irradiation and to understand the irradiation damage mechanisms. Zwick was the only manufacturer who could provide a solution for this unique application.

The ZHU0.2/Z2.5 has a load range of 2 - 200N, and a displacement measuring resolution of 0.02m. The system is equipped with a fully automated X/Y table and Rockwell and Vickers indenters. The indentation can be viewed through a microscope fitted with a CCD camera.

The Zwick ZHU0.2/Z2.5 is installed in a gas tight hot cell with 200 mm lead / 500 mm lead glass shielding. It carries out multistage indentation tests (load/unload) with different holding times. Neural networks then evaluate the correlation between these test data and the parameters of a viscoplastic material model, normally acquired from tensile tests.

The unique operation of the indentation tester allows it to carry out precision loading cycles up to various forces and displacements with predetermined holding times during each cycle. testXpert® , Zwick's software platform for materials testing, is used to control the machine and obtain the synchronised force and indentation data. This data is then stored in a special format and transmitted to the neural network system to determine the material properties such as Young's Modulus, Yield and ultimate tensile strength as well as hardening coefficients.

For more information contact Zwick at info(at)zwickroell.eu

About the Zwick Roell Group
The Zwick Roell Group is a global leader in automated materials and component testing systems. With 150 years of testing experience and operating worldwide, it has manufacturing facilities in Germany and distribution and customer support headquarters in Atlanta, Georgia, USA, and Singapore. As of 2006 the group has 900 employees and sells to 20 different industry sectors through a network of sales and service offices in 56 countries. For more information see www.zwick.com