Hannover 2010 – scientific programme

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P: Fachverband Plasmaphysik

P 15: Invited Talks Mayer, Liang, Wolfrum, Schulz-von der Gathen

P 15.1: Invited Talk

Thursday, March 11, 2010, 11:00–11:30, B 305

Hydrogen retention in tungsten - from laboratory experiments to ITER — •Matej Mayer, Olga Ogorodnikova, Volker Rohde, Joachim Roth, pwi team, and asdex upgrade team — Max-Planck-Institut für Plasmaphysik, EURATOM Association, Garching, Germany

ITER will use deuterium and tritium as fusion fuels. Both hydrogen isotopes can be retained in plasma-facing materials by implantation, diffusion, and co-deposition with eroded material. The accumulation of tritium is an important safety concern for ITER due to its radioactivity, and the maximum amount of tritium in the vessel is restricted.

A decrease of the retained hydrogen inventory by about one order of magnitude could be demonstrated at ASDEX Upgrade by replacing all plasma-facing components made from carbon by tungsten. Laboratory experiments on hydrogen retention in and permeation through tungsten allow a detailed understanding of the physics of hydrogen behavior in tungsten. Implanted hydrogen atoms can diffuse and are trapped in natural and ion induced defects. Plastic deformations of the tungsten material due to hydrogen accumulation are observed at high fluences.

The combination of laboratory and tokamak data allows a reliable extrapolation to hydrogen retention in ITER, which can be significantly reduced by replacing carbon by tungsten.