Characterization of 2D-C/C composite for application to in-core structure of Very High Temperature Reactor (VHTR)

Shibata, Taiju; Sumita, Junya; Kunimoto, Eiji; Sawa, Kazuhiro

Proceedings of 2008 International Conference on Carbon (Carbon 2008) (CD-ROM), 5 Pages, 2008/07

Very High Temperature Reactor (VHTR) is an advanced high temperature gas-cooled nuclear reactor to provide high temperature helium gas about 950 C to the reactor outlet. To enhance its performance, it is important to develop heat-resistant ceramics composite material in the core so as to increase the operating temperature. For the application of the 2D-C/C composite (CX-270G), neutron irradiation effects on the dimension and thermal conductivity were studied. Neutron irradiation test was carried out by JMTR at 600 C to the fluence of 8.210 n/m (E1.0MeV) corresponding to 1.2 dpa. It was shown that the irradiation-induced shrinkage of plain-woven CX-270G expressed the same trend of 2D- random fiber composite. The neutron irradiation decreased thermal conductivity of CX-270G and it seemed to be recovered to some extent above 1200 C. It is thought that the annealing effect on irradiation-induced defects in fiber direction affects the recovery.