Swelling of nuclear graphite and high quality carbon fiber composite under very high irradiation temperature

The purpose of this experiment was to evaluate the dimensional change of newly proposed nuclear graphite material following high-temperature irradiation, and to compare the measured swelling with the historic nuclear graphite, H-451. Over the irradiation temperature range studied (∼850–1475 °C) and neutron dose range (2–10 × 1025 n/m2 (E > 0.1 MeV)) the Graftech PCEA and SGL NBG-10 candidate nuclear graphite had similar densification to that of Great Lakes Carbon nuclear graphite H-451. In this temperature and dose range all materials remained in the densification stage. Additionally, the effect of high-temperature irradiation on the dimensional stability of high-quality carbon fiber composites was investigated. A high thermal conductivity three-dimensional carbon fiber composite, FMI-222, and a very high thermal conductivity one-dimensional carbon fiber composite MKC-1PH, were studied. Results indicate that a greater than anticipated dimensional change occurred for these composites. Moreover, the dimensional stability of the 3D composite appears to be a strong function of the sample size chosen, thus raising the question of the appropriate size sample to use to determine irradiation-induced dimensional change for these materials.