Novel Pyrolytic Boron Nitride Coating to Reduce Graphite Interactions in Molten Fluoride Salt

Abstract

Future salt reactors like the Fluoride-salt-cooled-High Temperature Reactor require varying material flavors. Graphite is required for neutron moderation and potential fuel forms, while structural metals are required for containment. Studies show graphite/metal interactions exist when both materials share a salt medium. These interactions may accelerate the corrosion of the metal and change the surface of graphite materials. A novel pyrolytic boron nitride coating on graphite is investigated for reducing graphite/metal interactions. This is the first known application of such a coating, and salt exposure tests reveal the pyrolytic boron nitride coating reduces the interactions between stainless steel and uncoated graphite.

Keywords: molten salt, corrosion, graphite, stainless steel, mass transport