Study of the Surface Morphology and Deuterium Desorption in KSTAR-like Graphite Irradiated with Low-Energy Deuterium Plasmas

The first wall of the Korea Superconducting Tokamak Advanced Research (KSTAR) is covered with graphite tiles. KSTAR-like graphite was fabricated as samples with a dimension of 10 × 10 × 1 mm3, and the samples were irradiated with 100-eV deuterium plasmas by using an electron cyclotron resonance system. Irradiations were performed for 30 min and 120 min under a 2.77 × 1021 m−2s −1 particle flux; irradiations for 30 min and 120 min had equivalent fluences of 4.99 × 1024 m−2 and 1.99 × 1025 m−2, respectively. Changes in the surface morphology due to the irradiation were examined with field-emission scanning electron microscopy. In addition, deuterium gas desorbed from the samples was investigated by using a thermal desorption spectroscopy system, where the samples were linearly heated from 550 K to 1100 K at a constant ramp rate of 0.1 K/s or 0.3 K/s.