Thermal shock fracture of graphite armor plate under the heat load of plasma disruption

• Published in: Fusion engineering and design 1989, Vol.9, p.181-186
• Main Authors: Horie, Tomoyoshi, Seki, Masahiro, Yamazaki, Seiichiro, Mohri, Kensuke, Ohmori, Junji
• Format: Article
• Language: English
• ISSN: 0920-3796; 1873-7196
• DOI: 10.1016/S0920-3796(89)80031-6

Experiments on the thermal shock brittle fracture of graphite plates were performed. Thermal loading which simulated a plasma disruption was produced by an electron beam facility. Pre-cracks produced on the surface propagated to the inside of the specimen even if the thermal stress on the surface was compressive. Two mechanisms are possible to produce tensile stress around the crack tip under thermal shock conditions. Temperature, thermal stress, and the stress intensity factor for the specimen were analyzed based on the finite element method for various heating conditions. The trend of experimental results under the asymmetric heating agrees qualitatively with the analytical results. This phenomenon is important for the design of plasma facing components made of graphite. Establishment of a lifetime prediction procedure including fatigue, fatigue crack growth, and brittle fracture is needed for graphite armors.