Structural and mechanical properties of different types of graphite used in nuclear applications

Abstract Graphite is known as a material with excellent thermo-mechanical, structural and neutron moderation properties. It is currently used as a core structural component for High Temperature Gas Cooled Reactor (HTGR). It is due to the fact that graphite has been extensively tested and proved to satisfy most of HTGR operating requirements. However, one question still remain unclear. Graphite, depending from the manufacture method, type and purity shows different mechanical and structural properties. In addition to that, literature data is poor in comparative studies of current and used in the past materials. For this reason, series of tests involving Scanning Electron Microscopy, Raman Spectroscopy, X-ray diffraction and nanoindentation have been performed on the virgin samples of two types of nuclear graphite’s: IG-110 and nuclear graphite used in decommissioned EWA reactor. Obtained results clearly shows differences in microstructural and mechanical properties of both types of graphite’s. Reported changes have been discusses and attributed to the density of the material and its origin.