NEUTRON-IRRADIATION EFFECTS ON THE PROPERTIES OF CARBON MATERIALS

Carbon-based materials are being widely used in present tokamaks, because of their favourable properties, especially with respect to their thermal shock resistance. However, the significant effects resulting from neutron irradiation on the thermal-physical, mechanical properties and on the tritium trapping capacity could preclude the utilization of carbon as a plasma facing material in forthcoming devices. Therefore, the effects of neutron irradiation are of primary concern in the use of carbon materials in the next step devices. This paper presents the latest results of experimental investigations on the effects of neutron irradiation on the thermal-physical, mechanical properties and tritium retention behaviour of various graphites and carbon/carbon fiber composites for the doses of 10(-3)-30 dpa and irradiation temperatures of 200-1500 degrees C. The state of experimental investigation of the behaviour of plasma hydrogen isotopes in carbon materials is given. In particular, the issue of neutron-induced changes in tritium behaviour is critically analysed.