Neutron irradiation effects on the thermal conductivity and dimensional stability of carbon fiber composites at divertor conditions

In continuation of our study on neutron induced property changes of carbon fiber composites at low irradiation temperatures and low neutron doses, an experimental study on the changes of dimensional stability and thermal conductivity has been performed. The irradiation temperatures are between 385 and 420 C, and the neutron damage is between 0.41 and 0.83 dpa (graphite). The investigated materials include: A 05 (2D felt-type CFC), CX 2002U (2D felt-type CFC), DMS 678 (2D woven CFC), N 112 (3D CFC), N11 (3D CFC), FMI A27-130 (3D CFC) and MKC (1D CFC). The results show that dimensional changes in both parallel and perpendicular directions are negligibly small, whilst the ratios of the irradiated thermal conductivity (Ki) to that of unirradiated (K0) are between 0.28 to 0.38 under those irradiation conditions. The results are critically analysed and discussed. (orig.)