SiC as a core-edge integrated wall solution in DIII-D

Abstract

Silicon carbide (SiC) is a promising material for use in a fusion reactor due to its low hydrogenic diffusivity, high temperature strength and resilience under neutron irradiation [1,2]. To assess SiC as a main wall material in DIII-D, simulations with TRIM.SP and DIVIMP are performed on a well-diagnosed L-mode discharge. The effective charge, Zeff, across the separatrix is used as a figure of merit in comparing SiC to the current graphite walls. It is found that SiC is expected to reduce Zeff, potentially by as much as ∼50 %. It is discussed how SiC may be expected to “self-condition” and create wall conditions similar to siliconization, further lowering Zeff due to efficient oxygen gettering. The potential benefits are reviewed and a path towards SiC walls in DIII-D is presented.

Keywords

• nuclear fusion
• DIII-D
• impurity transport
• silicon carbide
• wall conditioning
• DIVIMP