DEPOSITION OF PYROLYTIC CARBON IN PORES OF GRAPHITE BODIES .I. INTRODUCTION TO AND RESULTS OF DEPOSITION EXPERIMENTS USING METHANE

Graphite in nuclear reactors is oxidized very slowly and selectively by the coolant leading to a progressive loss in strength of the graphite bodies. It is well known that the application of a pyrolytic carbon layer permits protection of the graphite against such oxidative attack. An outer surface coating alone, however, has the disadvantage that in case of even very small damages to the coating, the oxidizing gas can enter the pore system and gradually deteriorate the basic graphite. For an efficient protection it is therefore necessary to deposit the pyrolytic carbon layer within the pore system. Experiments using methane have been performed to study such deposition in the pore system. The influence of various parameters (temperature, pressure, gas velocity) has been studied. © 1968.