Depth profile and retention of hydrogen isotopes in graphite tiles used in the W-shaped divertor of JT-60U

On the possibility of ITER starting with full carbon

“…Recent studies in JT-60U and JET indicate that carbon erosion and tritium retention in ITER could be smaller than the present estimation [12][13][14][15][16][17]. The purpose of this paper is not to deny the utilization of metallic materials as PFM but to suggest starting ITER with full carbon PFM.…”

“…In JT-60U, which is operated at 570 K with inertially cooled divertor structure, H/C in the deposited carbon on the outer divertor area was below 0.04 as seen in Table 1 [14]. The deposited carbon was not amorphous like but rather well graphitized and not easy to remove [31].…”

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

“…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.…”

Overview of research and development activities on fusion nuclear technologies in Japan

“…T retention profile in the divertor area was completely separated from H and D profiles because most of T produced by DD reaction was implanted directly into the plasma facing surface without fully loosing its initial energy [28,29]. On the other hand, H and D retention profiles in the divertor region well correlated with the carbon deposition profiles [30]. The retained amount in the deposited layers, however, was very small (below 0.03 in (H + D)/C).…”