Please cite this article in press as: P. Santos Silva, et al., Thermal analyses of the mm-waveguide cooling concepts for the ITER electron cyclotron upper launcher first confinement system, Fusion Eng. Des. (2017), http://dx.doi.org/10.1016/j.fusengdes.2017.03.081 ARTICLE IN PRESS G Model FUSION-9261; No. of Pages 6 Fusion Engineering and Design xxx (2017) xxx–xxx Contents lists available at ScienceDirect Fusion Engineering and Design journal homepage: www.elsevier.com/locate/fusengdes Thermal analyses of the mm-waveguide cooling concepts for the ITER electron cyclotron upper launcher first confinement system Phillip Santos Silva a,∗ , Robert Bertizzolo a , René Chavan a , Mario Gagliardi b , Timothy Goodman a , Jean-Daniel Landis a , Avelino Mas Sánchez a , Gabriella Saibene b a Ecole Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland b Fusion for Energy, Josep Pla 2, Torres Diagonal Litoral B3, Barcelona 08019, Spain h i g h l i g h t s • Presentation of two variants of a novel high-power waveguide cooling design. • Fluid dynamic simulation at nominal ECH power transmission. • Transient analysis of a typical ITER thermal cycle. • Manufacturing and assembly concept for the waveguide cooling channels. a r t i c l e i n f o Article history: Received 28 September 2016 Received in revised form 12 January 2017 Accepted 15 March 2017 Available online xxx Keywords: ITER Upper launcher Waveguide Cooling Coupling Thermal analysis First confinement system a b s t r a c t The ITER Electron Cyclotron Heating Upper Launcher (ECHUL) will be used to drive current locally inside magnetic islands located at the q = 2 (or smaller) rational surfaces in order to stabilize neoclassical tearing modes (NTMs). Each antenna consists of eight beam lines that are designed for the transmission of up to 1.5 MW of mm- wave power at 170 GHz, with at least 90% of the power in the main HE11 mode. Mm-wave power is assumed to be converted into heat by ohmic dissipation in the waveguide, with intensity peaks reaching up to 9000 W/m 2 , consequently to enable continuous working operation at nominal transmitted power, temperature control of the waveguide is required via an active cooling system. Available commercial solutions for the cooled waveguide are incompatible with the FCS, which will be subject to higher heat fluxes and shall comply with ITER SIC-1 requirements. Therefore a dedicated cooling system must be designed. This study presents the results of the thermal mechanical analyses of two different cooling concepts, and concludes the most suitable concept for the final Upper Launcher FCS system design. © 2017 Elsevier B.V. All rights reserved. 1. Introduction Each of the fours antennas consists of eight beam lines that are designed for the transmission of up to 1.5 MW of mm-wave power at 170 GHz (30.000 thermal cycles with pulse durations from 400 to 3600 s [1]), estimated losses are considered additive and mm-wave power is assumed to be converted into heat by ohmic dissipation in the waveguide, with intensity peaks reaching up to 9000 W/m 2 (Fig. 1). The UHV transmission lines in the FCS (First confinement sys- tem), for which SIC-1 classification requirements apply, consists of ∗ Corresponding author. E-mail address: phillip.santossilva@epfl.ch (P. Santos Silva). a Z shaped set of straight corrugated aluminum alloy (EN AW-6061) waveguides (WG), totaling 12.8 m, connected by miter bends with a nominal inner diameter of 50 mm (Fig. 1). For continuous working operation at nominal transmitted power, temperature control of the waveguide is required via an active water cooling system. Available commercial solutions for the waveguide are incompatible with the FCS, which will be subject to higher heat fluxes and must comply with ITER SIC-1 [2] require- ments. SIC-1, is the highest safety importance class, which consists of all components that are necessary maintain ITER in a safe state. Therefore a dedicated cooling system must be designed. Following the design and analysis evolution of several cooling concepts, this study presents the results for the cooling system deemed most suitable for the final FCS system design. http://dx.doi.org/10.1016/j.fusengdes.2017.03.081 0920-3796/© 2017 Elsevier B.V. All rights reserved.