Characterization of Pore Structure of Nuclear Grade Graphite Using Image Analysis Technique and Mercury Porosimetry

In a very high temperature reactor, graphite core components are stressed due to dimensional change and irradiation creep so that the integrity of the graphite component must be accessed by evaluating the cracking and failure of graphite. Normally polycrystalline graphite fails through a crack initiation induced by stress/inherent flaw, sub-critical crack growth from pore to pore and final propagation of a critical defect. Consequently, the information on the pore structure is inevitably necessary to understand and model the fracture behavior of nuclear graphite. In this study, the pore structures of commercially available nuclear graphites were investigated using an optical image analysis method and mercury porosimetry