Material damage in graphite by run-away electrons
Graphite limiters in the KFA tokamak TEXTOR have been hit by run-away electrons, which "burned" craters into the material surface. The craters have been formed by material erosion and/or sublimation and by chipping off thin laminates from the surface and additionally by redeposition of graphitic material. Moreover, thin metallic layers have been detected which may have been redeposited independently from the run-away electron event, and which could be found also outside the run-away electron crater. The redeposited carbon showed primarily two types of structure, namely orientated pyrocarbon and carbon-black-like material. The crater has been investigated by metallography, optical microscopy, secondary electron microscopy combined with energy-dispersive X-ray analysis, and automatic quantitative image analysis. The examined parameters are crater geometry, cracking behaviour and type and structure of redeposited material.
Bibliographic Reference: Article: Journal of Nuclear Materials, Vol. 162-164 (1989), pp. 970-975
Record Number: 199010364 / Last updated on: 1994-12-01
Original language: en
Available languages: en