Irradiation Characteristics of Non-Impregnated Micropore Graphite for Use in Molten Salt Nuclear Reactors

Non-impregnated small-pore graphite (NSPG), which has a compact microstructure and is used in molten salt reactors (MSRs), was prepared by a novel process. The pore diameter of NSPG was reduced to ~800 nm. The irradiation evaluation of NSPG was carried out by 7 MeV Xe26+ ion irradiation. The microstructural changes of NSPG were investigated with IG-110 as a comparison. The graphitization degree of NSPG was higher than that of IG-110, though it was not subjected to an impregnation process. Under low-dose ion irradiation (<2.5 dpa), the microscopic morphology of the NSPG changes in a small magnitude, and the lamellar structure of graphite remains within the scale of more than a dozen nanometers, which exhibits a better resistance to irradiation. With the increase in irradiation dose, the accumulation of defects leads the graphite toward amorphization, which shows consistency with IG-110. This study provides an efficient and low-cost method for the preparation of graphite for MSR, and investigates the damage behavior of graphite, which is of great significance in accumulating data for the development of MSR nuclear graphite and the optimal design of graphite materials.