Studies on the core-support carbon material for VHTR, (5)

Carbon material is one of the candidate materials for use as core-support and thermal barrier in the experimental VHTR. Stabilities of dimension and thermal conductivity at high temperature are important properties which should be intensively studied from the viewpoint of the design of the reactor core. Dimension, thermal conductivity, bulk density, and electrical resistivity were measured at room temperature after heat treatments at 1000 - 12000C for the maximum 6350 h for the carbon material baked at 11000C. It was clarified in the present experiment that dimension shrinked, thermal conductivity and bulk density decreased with heat treatment time after heat treatment even at 10000C which is below the baking temperature. The experimental results are presented and discussed, and the relation between thermal conductivity and crystallite parameter was discussed as well. (author)