Investigation of the retention mechanisms of hydrogen in beryllium tungsten compounds

In the experimental fusion reactors JET and, in the future, ITER, the first wall in the main room will consist of beryllium (Be). Tungsten (W) is also used in areas with the highest thermal loads (divertor). The hydrogen isotopes deuterium (D) and tritium (T) are used as fuel. Due to the contact of the reactor wall with the D- and T-ions, the surface material is among other things eroded and deposited at other locations. This produces Be-W compounds. Since the radioactive T is stored in the wall during reactor operation, the investigation of the hydrogen inventory, in particular the retention mechanisms in Be-W alloys, is of particular interest. The Ultra High Vacuum Experiment called ARTOSS will be presented, which combines all relevant surface analyses and thus enables the in situ preparation and analysis of corresponding materials under well-defined conditions. The ion bombardment in the reactor is simulated with an ion source. With voltages up to 20 kV D- and hydrogen ions are implanted in Be-W compounds. In addition first investigations by X-ray photoelectron spectroscopy (XPS), thermal desorption spectroscopy (TDS) and nuclear resonance analysis (NRA) are shown.