Hydrogen isotope retention of JT-60U W-shaped divertor tiles exposed to DD discharges

Tritium removal by isotopic exchange

“…Histories of plasma operation and of plasma exposure of analyzed tiles are summarized in Fig. 2 [7,12,13]. In the divertor area, the inner divertor and the dome tiles were deposited, while the outer divertor tiles were mostly eroded.…”

“…In our recent work on hydrogen isotopes retention in plasma facing tiles of JT-60U, we have found that distribution of hydrogen isotopes is quite non-uniform in depth, poloidal and toroidal positions, and eroded and deposited areas. In addition discharge history and tile temperatures significantly modify the depth distribution [3][4][5][6][7][8][9][10].…”

“…Taking profiles of re-deposition/erosion, heat load to the tiles and hence changes of surface temperatures during plasma discharges into account, the mechanism of incorporation of H and D in eroded and re-deposited carbon tiles in the W-shaped divertor region [7,8] and main chambers [9,11] is discussed. Based on these results, we suggest how isotopic exchange during plasma operation is effective to remove tritium retained in the plasma facing surface in a DT reactor.…”

Deuterium depth profiling in JT-60U tiles using the D(3He,p)4He resonant nuclear reaction

“…Recently, detailed analyses of deuterium and hydrogen in plasma-facing graphite tiles of JT-60U have been performed using secondary ion mass spectroscopy (SIMS), thermal desorption spectroscopy (TDS), a nuclear reaction analysis (NRA) and a scanning electron microscope (SEM) [5][6][7][8].…”

Neutron elastic recoil detection for hydrogen isotope analysis in fusion materials

“…The study of the behavior is important for the design of the fuel recycling, plasma control, safe management of tritium inventory, etc. If carbon-based materials as PFC, co-deposited layers of carbon compounds are formed with the thickness of several tens of micrometers on PFC surfaces due to plasma-wall interactions [1][2][3][4]. Therefore, it is necessary to measure hydrogen isotope depth profiles in these layers.…”