Search

The European DEMO (EU-DEMO) reactor studies within EUROfusion aim to develop a fusion power plant concept. The large tokamak device needs an auxiliary heating power which, at the present stage, is provided by the Electron Cyclotron (EC) heating system with up to 130 MW foreseen to reach different regions of plasma for heating, suppression of instabilities and the possibility to support ramp-up and ramp-down phases. The present conceptual design of the system is based on 2 MW coaxial-cavity gyrotron sources, a transmission line (TL) using both circular corrugated waveguides and quasi-optical evacuated multi-beam TLs, and mirror antennas located in the Equatorial Port. In order to create a modular system, the sources are grouped in 'clusters', whose powers are combined in the quasi-optical TL, up to the tokamak building, where they are split and routed as single waveguides. In the launcher, they are combined together again on the launching mirrors, to save space for the apertures in the Breeding Blanket. The present EC heating system has a certain flexibility to adapt to changing design guidelines. The development status of the system is presented. [ABSTRACT FROM AUTHOR]

The Divertor Tokamak Test (DTT) facility has been proposed in the European roadmap to study solutions to mitigate the issue of power exhaust in conditions relevant for DEMO. The Italian DTT tokamak [1] is being designed to reproduce the optimal divertor magnetic configuration and test a prototype under reactor relevant power flow in the scrape off layer (P SEP /R>15 MW/m). A mix of three heating systems will equip the machine to reach the target value of 45 MW delivered at plasma: Electron Cyclotron Heating (ECH), Ion Cyclotron Heating (ICH) and Negative Neutron Beam Injector (NNBI). The present reference design considers a capability of 20–30 MW of ECH power at plasma to support and assist different tasks. The gyrotron sources (1 MW/170 GHz/100 s) will be based on the depressed collector technology with >40% efficiency and will exploit the experience gained from the solutions developed for ITER. A Transmission Line (TL) with 90% efficiency and >1 MW/beam power handling is being considered, using Quasi-Optical (QO) multi-beam mirrors. The conceptual design of equatorial and upper launchers based on the front steering concept is being developed to reach the required deposition locations for the given application. The EC wave absorption efficiency has been investigated and is presented here with dedicated beam tracing calculations using the GRAY code [ 2 ]. [ABSTRACT FROM AUTHOR]

• The preliminary conceptual design for the EC system of the future EU DEMOnstration fusion power plant is ongoing in the EUROfusion Consortium. • Different options for the antenna, RSA, OEWG and MSA are investigated, analyzing their performance for several injection angles and launch points. • Beam tracing calculations have been performed on different scenarios, providing information on plasma accessibility and deposited power. • The microwave design and initial ideas about the ex-vessel EC transmission lines routing is approached. The preliminary conceptual design for the Electron Cyclotron (EC) system of the future European DEMOnstration fusion power plant is ongoing in the EUROfusion Consortium. This represents one of the key aspects in order to assess the performances and the integration capabilities of such a system in EU DEMO as well as in the alternative reactor configuration Flexi-DEMO. Different options for the antenna, namely remote steering antenna (RSA), open ended waveguides (OEWG) and the front steering antenna (FSA) later on renamed in mid steering antenna (MSA) to notify that the MSA is protected behind the breeding blanket (BB) in DEMO, are investigated, analyzing their performance for several injection angles and launch points. This activity considers the constraints given by physics and engineering requirements, as for example the maximum power per port and the necessary local current drive to stabilize neo-classical tearing modes (NTMs) with a proper deposition width. The beam tracing calculations have been performed on different scenarios, providing information on plasma accessibility and deposited power. The microwave design and initial ideas about the ex-vessel EC transmission lines routing will be shown. [ABSTRACT FROM AUTHOR]