In-situ tokamak laser applications for detritiation and co-deposited layers studies

摘要

Treatment of plasma facing components (PFCs) is a major issue for ITER operations and may be applied for different reasons. As a most important application, there is the control of tritium inventory to fulfil the safety requirements. In the following, a solution based on laser techniques is presented. Due to its flexibility, its capability to reach difficult access structures as voids or castellation and the possibility to be installed on remotely controlled devices, laser offers one of the most suitable solution for detritiation of the PFCs via ablation process. In the following, the high ablation efficiency as well as the capability to detritiate co-deposited carbon layer without any interaction with bulk material will be discussed. Then laser induced breakdown spectroscopy (LIBS) will be described with a new diagnostic based on the study of the surface temperature response after a heating laser pulse. It will be shown that used together, the two techniques allow the determination both the concentration of tritium in co-deposited layer as well as the total quantity of carbon co-deposited on top of bulk material. These two bits of information are essential to determine when the detritiation process must take place and how long it should last. Finally, the still open issues will be presented that need to be developed in order to apply this global laser system in tokamaks. (c) 2007 Elsevier B.V. All rights reserved.