Deuterium retention in Tore Supra long discharges

Tritium retention is a crucial point to investigate for next step machines using carbon plasma facing components. In order to address this issue, particle balance has been performed on Tore Supra long discharges, allowing to estimate the wall deuterium inventory. In these conditions, large dynamic deuterium retention rates have been observed (up to 50% of the injected fuel). This paper presents a summary of the experimental results in terms of wall retention during the shot and particle recovery after the shot, as well as after glow discharges and disruptions. Particle balance integrated over a campaign is also estimated and compared with the D inventory deduced from sample analysis. Different mechanisms are then reviewed in order to explain this particle balance, from D particle implantation to carbon porosity filling and codeposition. Rough estimates of each process contribution to the retention rates are given and compared with the experimental observations. (author)