Effect of Heat Treatment on Property of Phenol Resin Carbon of Pebble Fuel Element for HTGR

In order to study the effects of heat treatments such as the carbonization and high temperature purification (HTP) on the properties of phenol resin (PR) carbon of pebble fuel elements for HTGR, the micro-structure and physical properties of PR carbon after carbonization and further HTP were comparatively analyzed. The results indicate that comparing with the PR carbon obtained by carbonization, the PR carbon treated with further HTP exhibits higher degree of graphitization and larger average pore size, and has specific surface area of less than 50%. In the dry air atmosphere, the PR carbon treated with further HTP possesses lower oxidation rate and higher oxidation resistance property. The improvement of graphitization degree of PR carbon with further heat treatment of HTP is beneficial to upgrade the integrated properties of pebble fuel elements.