Vapor deposited silicon carbide has a very low tritium diffusivity and
solubility. When these characteristics are combined with its very goo
d thermal properties, silicon carbide appears to be an excellent triti
um permeation barrier for use in fusion reactors and other application
s. Calculations were performed to compare the tritium retention in bar
e graphite and graphite coated with a thin layer of silicon carbide. T
he coated graphite retained several orders of magnitude less tritium t
han the bare material. Similar calculations showed a beryllium/copper
duplex structure coated with silicon carbide to anew several orders of
magnitude less tritium permeation than an uncoated structure.