A tritium inventory management scheme for BPX

Operation of the Burning Plasma Experiment (BPX) with a deuterium-tritium plasma and graphite divertor plates will result in significant retention of tritium in layers of eroded and subsequently redeposited carbon. This trapped tritium is at risk of release during a vacuum accident. An administrative limit of 2 g of releasable tritium has been established for assessment of the environmental impact of such an event. Analysis of the erosion and redeposition process indicates that the 2-g limit will be reached in about 200 full-parameter discharges. Helium-oxygen glow discharge cleaning will be used to remove the redeposited carbon and the trapped tritium. It is calculated that about 90 h of cleaning are required to remove the trapped tritium from 200 plasmas. The cleaning will be done during scheduled maintenance periods every third week. Studies indicate that the tritium inventory can be effectively managed with helium-oxygen glow discharge cleaning