Correlation between hydrogen isotope profiles and surface structure of divertor tiles in JT-60U

Hydrogen isotope distributions and retentions in the inner divertor tile of JT-60U

“…In this work, we have focused on the inner divertor target tile named 5DV1bq, on which divertor-strike-points hit in most of discharges, and made detailed analysis. The history of the tile was described in our previous paper [6,7]. In most of DD discharges, the divertor-strike-points were situated on this tile and, for HH discharges, in particular, they were at 150-200 mm in the poloidal position of the tile.…”

“…The depth profiles of hydrogen and deuterium in the samples were analyzed by secondary ion mass spectroscopy (SIMS) with using 5 keV of cesium ion (Cs + ) as a primary ion [5][6][7]. Signal intensities of H − and D − ions were normalized by that of 12 C − .…”

“…According to recent retention studies of hydrogen isotopes (hydrogen, deuterium and tritium) in plasma facing graphite 0920-3796/$ -see front matter © 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.fusengdes.2005.06.074 tiles used in JT-60U, most of tritium was implanted into plasma facing graphite tiles in the depth of micrometer range but not co-deposited with carbon, while hydrogen and deuterium were retained in very near surface [3][4][5][6][7]. In addition, hydrogen and deuterium distributions were quite different with each other showing much shallower depth profile for hydrogen.…”

“…In the previous papers [6,7], we have investigated retention behaviour of hydrogen isotopes of the outer divertor tiles and the dome top unit in JT-60U. Although erosion was dominated on the outer divertor tile, small amount of re-deposition layer existed near the pumping slot.…”

Retention and depth profile of hydrogen isotopes in gaps of the first wall in JT-60U

“…For this reason, it is important to investigate retention behavior of hydrogen isotopes in present tokomaks for prediction of tritium retention in ITER. In tokamaks, hydrogen (H) and deuterium (D) retention and carbon erosion/ deposition in the divertor area has been intensively investigated so far [2][3][4][5][6][7][8][9][10][11][12]. In JT-60U, it was found that the H + D retention in the plasma facing surface and the side surface of the graphite tile in the divertor area is of the order of about 10 22 -10 23 atoms/m 2 .…”