A REVISED ITER EC SYSTEM BASELINE DESIGN PROPOSAL

Mark A. Henderson, Stefano Alberti, Rene Chavan, Damien Fasel, Timothy P. Goodman,

Ioannis Gr. Pagonakis, Olivier Sauter, Ugo Siravo, Victor S. Udintsev, Costanza Zucca

CRPP - EPFL, Station 13, CH-1015 Lausanne

Gabriella Saibene, Ferran Albajar, Tullio Bonicelli

EFDA-CSU, Boltzmannstrasse 2, Garching, Germany 85748

Sante Cirant, Daniela Farina, Gabriella Ramponi

ENEA- CNR, Milano, Italy

Roland Heidinger, Bernard Piosczyk, Manfred Thumm

FZK, Karlsruhe, Germany 76021

The ITER EC system was designed on technologies established prior to the onset of multi-megawatt EC systems that are in use on many fusion devices around the world today. This implies that the design is somewhat outdated. To remedy this situation the ITER Organization (IO) requested the European Fusion Development Agreement (EFDA) to propose a revised EC system design and an updated Detailed Design Documentation (DDD). EFDA initiated this task early in 2006, but it was eventually put aside due to the more urgent ITER design review (DR) that took place during 2006 and 2007. The combination of these two activities has identified several shortcomings of the various EC subsystems and led to several proposals for improving the EC systems performance while reducing the overall cost and increasing reliability. These proposed revisions have now been assembled together into a coherent system design and offers an alternative baseline design of the EC system.

For example the use of pulse step modulated power supplies is recommended offering a more flexible control of the gyrotron output power and capable of adapting to the four different gyrotron types to be delivered to ITER. An alternative gyrotron layout is developed maximizing the maintenance access to each gyrotron, while ‘hiding’ the HE₁₁ waveguide, cooling lines and cable trays under a raised floor. The composition and configuration of the transmission line components is modified to reduce the total length and number of mitre bends, and thus losses and costs, while maintaining functionality. Changes to the transmission line connection to the gyrotron as well as the launchers are proposed that simplify the interface and increase maintenance access, reduces cost and is better adapted to the ITER EC procurement plan. Modifications of both launcher optical designs are proposed that reduce the complexity and costs, while offering a greater access and flexibility to the EC deposition range and physics capabilities.

The aim of this paper is to review the proposed alternative EC system design highlighting the potential savings or improvements over the present baseline design. Note that this work has been performed with informal collaboration with the EC systems experts in Japan and the US as well as formal collaboration with ITER.

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This work, supported by the Swiss National Science Foundation and the European Communities, was carried out within the framework of the European Fusion Development Agreement. The views and opinions expressed herein do not necessarily reflect those of the European Commission.