Long discharge particle balance and fuel retention in Tore Supra.
In the new CIEL configuration of Tore Supra, all the plasma-facing components are actively cooled. The surface of the wall covered with carbon is about 15 square metres (2 to 4 square metres of which in close interaction with the plasma). This configuration allowed researchers to maintain steady-state plasma conditions for up to 4min 25s. In these experiments, the required gas injection for maintaining the prescribed density remains constant during the whole discharge. The exhausted flux is also constant and equal to 40-50% of the injected flux. Therefore, 50-60% of the injected particles remain trapped in the vessel, the total retention being proportional to the plasma duration. Since the gas recovered between shots or by conditioning techniques is far from equilibrating the injected gas, huge quantities of deuterium remain indefinitely trapped in the wall, which appears as an infinite reservoir. This reservoir is believed to be dominated by co-deposited layers, as observed in several places of the vessel. The thickest deposits (up to 800jlm) are observed on the leading edge of the neutralizers of the exhaust system. They display a column-like shape (typical growth rate approximately 20nm/s) and have a graphite-like structure. Their deuterium content is modest. Conversely, when coming from regions protected from the direct plasma flux, the deposits show a smoother shape and their deuterium content is typically an order of magnitude larger.
Bibliographic Reference: An oral paper given at: 10th International Workshop on Carbon Materials for Fusion Application Organised by: Forschungszentrum Jülich Held at: Jülich, Germany, September 17-19, 2003 Papers are available online at: http://www.fz-juelich.d
Availability: Available from Association EURATOM-CEA, Département de Recherches sur la Fusion Contrôlée, CEA Cadarache, F-13108 St Paul-Lez-Durance, France Tel:+33-4-42257001; Fax:+33-4-42256421 E-mail: email@example.com
Record Number: 200317073 / Last updated on: 2003-10-27
Original language: en
Available languages: en