Identification and location of 14C-bearing species in thermally treated neutron irradiated graphites NBG-18 and NBG-25: Pre- and post-thermal treatment

Recent studies have been performed to determine the effectiveness of thermal treatment as a method for removing 14C contamination from irradiated graphite surfaces. Samples of two grades of irradiated nuclear graphite (NBG-18 and NBG-25) were thermally treated to determine the amount of 14C contamination on irradiated graphite surfaces. The results of these analyses indicate that specific chemical forms of 14C (namely, 14CO and 14CO2) may be selectively removed based on the temperature used during thermal treatment. Characterization studies utilizing various surface analysis techniques (XPS, SIMS, SEM/EDS) were employed to investigate the chemical speciation, bond structure, and morphology of the surfaces of pre- and post-thermally treated irradiated graphite.