Tritium absorption/desorption in ITER-like tungsten particles

• An original technique was used for tritium charging of tungsten particles and massive samples.
• When compared to massive samples, very large tritium amounts are incorporated in W particles.
• Surface effects are predominant on tritium absorption/retention in W particles.
• Tritium absorption and trapping depend on oxide films on W particles and on defects in massive samples.
• Absorption/retention of 3H in W may affect 3H management and radiotoxicity of ITER-like W particles.

Tritium retention in plasma facing materials such as tungsten is a major concern for future fusion reactors. During ITER operating mode, the reactor could generate tritiated tungsten dust-like particles which need to be characterized in terms of amount of trapped tritium, tritium source and radiotoxicity. This study is focused on the preparation and characterization of tungsten particles and on a comparative analysis of tritium absorption/desorption kinetics in these particles and in massive samples. An original gas phase thermal charging procedure was used successfully for tritium incorporation in tungsten powders and massive samples. Much larger tritium amounts are incorporated in W particles than in massive samples indicating important surface effects on tritium absorption, desorption and trapping in W. Tritium desorption from particles occurred at different temperatures related with different interactions on the particles surface and in the bulk; the tritium behavior in massive samples was also shown to depend on the metal microstructure. According to these experimental results tritium absorption/desorption in W particles may have important implications on tritium management in ITER reactor.