Thermo-Oxidation Experiments in the \hbox{DIII-D} Tokamak

To evaluate the effectiveness of removing carbon co-deposits and trapped deuterium from tokamak surfaces by thermo-oxidation and to demonstrate the recovery of high performance plasmas, two independent thermo-oxidations of the \hbox{DIII-D} tokamak were performed. Graphite tiles containing $^{13}$C rich co-deposits and various witness samples were installed on passively heated, flange-mounted platforms for the first exposure. Plasma operations were recovered and followed by a series of $^{13}$C-seeded plasma shots. A second thermo-oxidation was performed, followed by a removal of select wall and divertor tiles. Results show a decrease in co-deposited $^{13}$C and D content on precharacterized tiles, and a temperature dependent uptake of D on stainless steel witness samples. Preliminary results, as well as operational and experimental details of the thermo-oxidation exposures are presented.