JULE-PSI project in Forschungszentrum Jülich for plasma-material interaction studies in nuclear environment
The JULE-PSI project at Forschungszentrum Jülich foresees a linear plasma device installed inside a hot cell. It will be capable of using materials activated by the neutron irradiation. The compatibility with toxic materials will allow for the tests of all ITER relevant wall materials including beryllium.
The PSI-2 linear plasma device serves as the pilot experiment to test the technological solutions for JULE-PSI. In parallel, a comprehensive PMI research programme focused on the performance of the metallic materials under the intense plasma irradiation has been started. PSI-2 incorporates a steady-state arc plasma source with a heated LaB6 cathode of cylindrical shape and a plasma chamber with a solenoidal magnetic field of ~0.1 T. Material samples are exposed to a plasma column of »6 cm in diameter with an electron density of up to ~1019 m-3, an electron temperature of 1-20 eV and an ion flux of up to ~1023 m-2s-1. ITER relevant ion fluences of ~1027 m-2 can be achieved within a single multi-hour sample exposure.
In addition to the routinely used side-fed linear sample manipulator, a new target station for the sample manipulation has recently been installed in PSI-2. It allows a rapid target exchange without breaking the vacuum in the plasma vessel, in-vacuo surface analysis outside the running plasma, variation and control of parameters at the target such as surface temperature, biasing voltage, target inclination angle and gas injection. The in-vacuo analysis methods currently under development will include laser-based techniques such as desorption and breakdown spectroscopy as well as the glow discharge optical emission spectroscopy.
In this work Dr Kreter will present results investigating the influence of the incident ion flux on the D retention and surface morphology of tungsten in PSI-2 and Magnum-PSI/Pilot-PSI in pure D plasmas. The occurrence of blistering is correlated with the amount of retention. In addition the influence of helium and argon on the deuterium retention in tungsten was investigated in PSI-2.