29th Symposium on Fusion Technology (SOFT 2016)

P3.172 Displacement damage effect on the thermal stability of deuterium in SiC

7 Sep 2016, 11:00

1h 20m

Foyer 2A (2nd floor), 3A (3rd floor) (Prague Congress Centre)

Board: 172

Poster I. Materials Technology P3 Poster session

Speaker

Fernando Sanchez (National Fusion Laboratory (LNF))

Description

SiC is a primary candidate for flow channel inserts in blankets due to their excellent thermo-mechanical properties. During reactor operation SiC will be exposed to tritium in a hostile radiation environment. Absorption, diffusion, and desorption will occur, and are expected to depend on the neutron and ionizing radiation conditions. We present work to assess the effect of displacement damage on the thermal stability of deuterium in reaction bonded (RB) SiC in the temperature range 400 to 1000 C. The aim is to study the thermal stability of deuterium as a function of displacement damage induced with 50 keV Ne⁺+, either before or after deuterium implantation. Three experiments were carried out: first 10 keV D₂⁺+ ion implantation at 450 C in SiC samples for reference; second, pre-damage of SiC samples with 50 keV Ne⁺+, followed by deuterium implantation; and third in the reverse order for further SiC samples (deuterium implantation, followed by damage with Ne⁺+). After these treatments a sample of each method was examined using SIMS. A further three samples were heated up to 1000 C at a rate of 0.16 C/s, in order to obtain the deuterium thermally stimulated desorption (TSD) spectra. Following TSD measurements, these samples were examined using SIMS. TSD and SIMS analysis of reference samples show the deuterium retention in SiC is higher for the RB SiC pre-damaged with Ne⁺+ and also that the thermal stability of the deuterium is enhanced by traps induced by the Ne⁺+ damage. In contrast for the post-damaged samples, no difference was found compared with reference samples. This work shows that the displacement damage produced into SiC generates thermally stable traps for hydrogen isotopes. Following the initial trapping process, additional damage does not play an important role on the overall retention.