Thermal shock behaviour of H and H/He-exposed tungsten at high temperature

• Published in: Physica scripta Vol. T167; no. 1; pp. 14008 - 14012
• Main Authors: Lemahieu, N, Greuner, H, Linke, J, Maier, H, Pintsuk, G, Wirtz, M, Oost, G Van, Noterdaeme, J-M
• Format: Journal Article
• Language: English
• Published: IOP Publishing 20.02.2016
• Subjects: Crack initiation; Damage; divertor; ELMs; Exposure; Fracture mechanics; H beams; I beams; plasma wall interaction; Thermal shock; thermal shock resistance; Tungsten
• ISSN: 0031-8949; 1402-4896
• DOI: 10.1088/0031-8949/T167/1/014008

Polycrystalline tungsten samples were characterized and exposed to a pure H beam or mixed H/He beam containing 6% He in GLADIS at a surface temperature of 600 °C, 1000 °C, or 1500 °C. After 5400 s of exposure time with a heat flux of 10.5 MW m−2, the total accumulated fluence of 2 × 1025 m−2 was reached. Thereafter, edge localized mode (ELM)-like thermal shocks with a duration of 1 ms and an absorbed power density of 190 MW m−2 and 380 MW m−2 were applied on the samples in JUDITH 1. During the thermal shocks, the base temperature was kept at 1000 °C. The ELM-experiments with the lowest transient power density did not result in any detected damage. The other tests showed the beginning of crack formation for every sample, except the sample pre-exposed with the pure H-beam at 1500 °C in GLADIS. This sample was roughened, but did not show any crack initiation. With exception to the roughened sample, the category of ELM-induced damage for the pre-exposed samples is identical to the reference tests without pre-exposure to a particle flux.