SORPTION BEHAVIOR OF TRITIUM TO ISOTROPIC GRAPHITE

Sorption behavior of tritium to isotropic graphite is discussed includ ing solubility, diffusivity in the bulk of isotropic graphite and sorp tion capacity of hydrogen isotopes on the surface of isotropic graphit e. The solubility and the diffusion coefficient of hydrogen isotopes i n the graphite are obtained using the breakthrough method in the tempe rature range of 673 similar to 1273K and the activation energy of diff usivity is about 100kJ/mol.The sorption capacity of tritium on the gra phite surface is also obtained by the breakthrough method using tritia ted water in nitrogen gas flow. Tritium is captured on the graphite su rface by isotope exchange reaction between tritium in gas flow and hyd rogen in hydroxyl group on the graphite surface. These hydrogen atoms in hydroxyl group can easily exchange with other hydrogen isotopes in gas flow though they cannot be easily released from the graphite by dr ying or evacuating.