A Study on Deuterium Retention Behavior of Plasma-Facing Materials for EAST

To investigate the deuterium (D) retention behavior of plasma-facing materials (PFMs) in the Experimental Advanced Superconducting Tokamak (EAST), SiC-coated graphite, bulk W, and W coating were exposed to D plasmas employing the material and plasma evaluation system in EAST. A comparative study was performed in an electron cyclotron resonance (ECR) linear plasma facility as well. For the EAST experiments, the local electron temperature and density were
$T_{e}\approx$
10–15 eV and
$n_{e}\approx$
(1–3)
$\times$
10
¹⁸
m
⁻³
, respectively. In the ECR facility, the plasma parameters were measured to be
$T_{e} \approx 2.4$
eV and
$n_{e} \approx 1.5 \times 10^{17}$
m
⁻³
. The surface morphology was examined by scanning electron microscopy, and D retention properties of various PFMs were examined by thermal desorption spectroscopy. No significant modification of the surface morphology was observed after tokamak exposure experiments. Bulk W and W coating exhibit similar D retention behavior, while D inventory in SiC-coated graphite has been found to be much larger than that in W materials.