Author/Authors :
Oya، نويسنده , , Y. and Tanabe، نويسنده , , T. and Oyaidzu، نويسنده , , M. and Shibahara، نويسنده , , T. and Sugiyama، نويسنده , , K. and Yoshikawa، نويسنده , , A. and Onishi، نويسنده , , Y. and Hirohata، نويسنده , , Y. and Ishimoto، نويسنده , , Y. and Yagyu، نويسنده , , J. and Arai، نويسنده , , T. and Masaki، نويسنده , , K. and Okuno، نويسنده , , K. and Miya، نويسنده , , N. and Tanaka، نويسنده , , S.، نويسنده ,
Abstract :
Retention of hydrogen isotopes in the carbon (isotropic graphite) first wall tiles of JT-60U was studied by secondary ion mass spectrometry and thermal desorption spectroscopy. The surface morphology and erosion/deposition profiles of the tiles were characterized using scanning electron microscope and X-ray photoelectron spectroscopy. The upper area is mainly eroded, while the bottom area of the inboard wall is dominated by deposition. In contrast to the divertor area, hydrogen isotope retention in the eroded wall area was generally larger than that in the deposition dominated area. Measured near surface concentrations of hydrogen isotopes in the wall tiles, as well as the D/H ratios, were a little higher than those in the divertor area. This indicates direct implantation of high-energy D from NBI into the first wall. The lower temperature of the first wall relative to the divertor tiles would reduce desorption and/or replacement of implanted D by subsequent D or H impingement.
