Modelling Carbon for Industry: Radiolytic Oxidation

An ab initio density functional technique (AIMPRO) has been employed to investigate the structure, vibrational properties, and dissociation mechanisms of CO30, the important radical anion CO3- and the interaction of this species with the graphite basal plane. The results are discussed in the context of the radiolytic oxidation of graphite: a process of relevance to the British nuclear industry, which relies for the most part on graphite-cored, CO2-cooled reactors. The radiation field splits coolant molecules and produces, amongst other things, a very reactive radical anion CO3-, which has been suggested as the main agent for the accelerated oxidation of graphite. This paper shows that CO3- binds strongly to graphite after combining with an electronic hole and forming a long and strong ionic bond. It still remains mobile on the basal plane and can diffuse to a graphite edge and oxidize it.