Detection of Defective SiC Layers in Coated Nuclear Fuel Particles

A technique has been developed for detecting defective SiC layers in silicon carbide-pyrolytic carbon coated fuel particles. The outer coating of carbon is burned off at 800°C, and the particles are pressurized at 1000 lb /in.² in a mercury porosimeter. Mercury is forced through any defects in the SiC layer and into the porous carbon. The particles are examined by a low-voltage microradiographic technique. Defective particles were detected in some batches of coated fuel particles.