Studies on the core-support carbon material for VHTR, (1)

To obtain information of core-support carbon material for VHTR, thermal conductivity and electrical resistivity of three domestic carbon blocks were measured. Results indicated the need for development of carbon material with lower thermal conductivity for VHTR. These two were also measured of the samples heat-treated between 10000C and 30400C for one hour. Thermal conductivity increased with heat-treatment above 12000C and resistivity stayed constant between 15000C and 20000C. The results should be useful in choosing the final heat-treatment temperature in carbon material production. The changes of Lorentz number with heat treatment were classified into three heat-treatment temperature regions of below 15000C, 15000C - 25000C, and above 25000C; the results are interpreted with a graphitization model. (author)