Presentation Tritium retention characteristics in dust particles in JET with ITER-like wall

Otsuka, Teppei  ,  Masuzaki, Suguru  ,  Ashikawa, Naoko  ,  Hatano, Yuji  ,  Asakura, Nobuyuki  ,  Suzuki, Tatsuya  ,  Suzuki, Takumi  ,  Isobe, Kanetsugu  ,  Hayashi, Takumi  ,  Tokitani, Masayuki  ,  Oya, Yasuhisa  ,  Hamaguchi, Dai  ,  Kurotaki, Hironori  ,  Sakamoto, Ryuichi  ,  Tanigawa, Hiroyasu  ,  Nakamichi, Masaru  ,  Widdowson, Anna  ,  Rubel, Marek  ,  JET Contributors

We have applied a tritium imaging plate technique (TIPT) in combination with an electron-probe microscopic analysis (EPMA) to examine a tritium (T) retention characteristic in individual dust particle collected in the Joint European Torus with the ITER-like Wall (JET-ILW) after the first campaign in 2011-2012.Dust particles were collected from the inner divertor region in JET-ILW. A tiny amount of dust was taken from that sample and placed on the surface of a disk made of indium (In). The content of T retained at a surface of and/or in the dust particles was evaluated by TIPT: emission of beta-rays from T to the imaging plate (IP) was measured over a whole surface of the indium disk. Afterwards, EPMA was conducted to determine morphology (composition and structure) of the dust particles in the same surface area where the IP measurement was conducted. The obtained maps (images) of the T distribution and elemental compositions were super-imposed to reveal characteristic features of T retention in the individual dust particle.The results suggest that most of T was retained at the surface of and/or in carbon (C)-dominated dust particles. The characteristics of T retention in C-dominated dust particles are scattered. The retention in tungsten, beryllium and other metal-dominated dust particles is relatively small: smaller by a factor of 10 ~ 100 in comparison with that in the C-dominated particles.
The 23rd International Conference on Plasma Surface Interactions in Controlled Fusion Devices (PSI-23)

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