EQUIPMENT VARIABLES AND DEPOSITION CONDITIONS AFFECTING THE PLASMA OXIDATION OF PYROCARBON COATINGS ON HTGR FUEL PARTICLES

摘要

Selective etching with an oxygen plasma is a promising technique for revealing the structure of the high-density pyrocarbon (PyC) coatings used on HTGR nuclear fuel particles and can be used to predict the fast-neutron damage resistance of the PyC. Several factors that affect either the etching rate or the etch structure were examined in this investigation.nParticles with PyC coatings deposited from hydrocarbon MAPP gas (C3H4 isomers) under a variety of conditions were polished to the midplane and systematically plasma oxidized to determine the effect of the coating parameters on the observed etch structure. Identical coatings were then oxidized by use of different plasma parameters to determine the relation of the observed etch pattern to these parameters.