O2 erosion of graphite tile substrates

The removal of codeposited tritiated carbon films from the next generation of fusion reactors may rely on the use of baking in an O2 environment to remove the films. In the present study, we have investigated the effect of baking in O2 on graphite tile substrate materials. After baking five types of graphite in 2.1 kPa O2 for 100 h at 623 K, no change in mass was observed. An upper limit on the erosion rate was calculated to be ∼4×10−10 C/O2, whereas the codeposited films obtained from tokamaks have erosion rates as high as 10−5 C/O2.