Material testing facilities and programs for plasma-facing component testing

Abstract

Component development for operation in a large-scale fusion device requires thorough testing and qualification for the intended operational conditions. In particular environments are necessary which are comparable to the real operation conditions, allowing at the same time for in situ/in vacuo diagnostics and flexible operation, even beyond design limits during the testing. Various electron and neutral particle devices provide the capabilities for high heat load tests, suited for material samples and components from lab-scale dimensions up to full-size parts, containing toxic materials like beryllium, and being activated by neutron irradiation. To simulate the conditions specific to a fusion plasma both at the first wall and in the divertor of fusion devices, linear plasma devices allow for a test of erosion and hydrogen isotope recycling behavior under well-defined and controlled conditions. Finally, the complex conditions in a fusion device (including the effects caused by magnetic fields) are exploited for component and material tests by exposing test mock-ups or material samples to a fusion plasma by manipulator systems. They allow for easy exchange of test pieces in a tokamak or stellarator device, without opening the vessel. Such a chain of test devices and qualification procedures is required for the development of plasma-facing components which then can be successfully operated in future fusion power devices. The various available as well as newly planned devices and test stands, together with their specific capabilities, are presented in this manuscript. Results from experimental programs on test facilities illustrate their significance for the qualification of plasma-facing materials and components. An extended set of references provides access to the current status of material and component testing capabilities in the international fusion programs.

High-fluence and high-flux performance characteristics of the superconducting Magnum-PSI linear plasma facility

“…Transient plasma loading can also be compared to laser loading using a high-power welding laser (LASAG FLS 352-302) to generate 0.1-3 ms heating pulses on the target. As such, Magnum-PSI, together with other linear plasma generators and laboratory heat facilities [3] are deemed essential to predict plasma facing component (PFC) performance at high particle fluence (> 10 27 D + m -2 ) and high number of thermal cycles (>10 6 ELM-like events) within the EUROfusion consortium [4].…”

Self-organization of helium precipitates into elongated channels within metal nanolayers

“…All of these processing methods result in multiphase metal nanocomposites that provide the conditions needed for the formation of He channels, that is, nanoscale confinement of He precipitates between interfaces with location-dependent energies. Each of them requires extensive additional testing to determine their overall performance under plasma exposure ( 49 ).…”

Recent studies of tungsten-based plasma-facing materials in the linear plasma device STEP

“…Moreover, transient events such as edge-localized modes (ELMs) could be well simulated by a pulsed plasma in Magnum-PSI using a capacitor bank, meaning not only the plasma irradiation effect but also the heat load effect could be studied simultaneously [17]. Further information about LPD devices could be found in the reported reviews [18][19][20].…”