Speaker
Jochen Linke
(Forschungszentrum Jülich GmbH)
Description
To qualify new plasma facing materials (PFM) and to evaluate the high heat flux performance under ITER or DEMO relevant loading conditions, extensive High Heat Flux (HHF) testing is indispensable. This includes performance tests under cyclic stationary thermal loads and screening of different material candidates under relevant transients such as Edge Localized Modes (ELMs) with high pulse numbers. In addition, these thermal load tests have to be performed under conditions which also account for damaging influences such as the degradation due to plasma exposure by hydrogen and helium ions and the impact of energetic neutrons. Quasi-stationary and transient events performed under these harsh conditions have strong impact on the lifetime of the wall armour and – in the worst case – can result in a catastrophic failure of the PFCs.
Therefore, performance tests on specific PFCs in future fusion devices are not limited to thermal fatigue or thermal shock induced experiments under mitigated ELMs, but must also include neutron irradiation induced material degradation and the impact of hydrogen and helium induced effects (such as embrittlement, blistering and fuzz formation) to allow reliable predictions on the lifetime of PFCs. Due to the lack of a powerful 14 MeV neutron source, irradiation experiments with ITER relevant neutron doses are performed in fission type material test reactors. Plasma facing materials and components have been and are being irradiated up to ITER-relevant fluences of approx. 1 dpa at temperatures ranging from 200 to 700°C. Post irradiation examinations (PIE) include a detailed analysis of the heat flux performance under the above mentioned loading scenarios as well as the neutron induced degradation of thermal and mechanical properties. A new test facility at Forschungszentrum Jülich will also allow to study synergistic effects (combined thermal loads, plasma exposure and neutron irradiation effects).
Co-authors
Bernhard Unterberg
(Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung, 52425 Juelich, Germany)
Gerald Pintsuk
(Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung, 52425 Juelich, Germany)
Jochen Linke
(Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung, 52425 Juelich, Germany)
