QUALITY EVALUATION OF GRAPHITES AND CARBON CARBON COMPOSITES DURING PRODUCTION OF JT-60U PLASMA FACING MATERIALS

The variations of physical and mechanical properties have been investigated for three grades of isotropic graphites and four grades of carbon/carbon (C/C) composites on the basis of the sample inspection data which have been obtained during production of the first wall and divertor plate materials for JAERI Tokamak-60 Upgrade (JT-60U). The evaluated properties are density, electrical resistivity, coefficient of thermal expansion (CTE), thermal conductivity, bending, tensile and compressive strengths. It is found that the maximum standard deviations normalized by the mean values are 22.7% for the C/C composites and 9.2% for the isotropic graphites. This scatter of the material quality should be considered in the design of the isotropic graphite and C/C composite armor tiles. Correlations between these properties are also observed for several materials.