EU DEMO EC equatorial launcher pre-conceptual performance studies

Abstract

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.

Drift kinetic effects and local current drive induced modification of magnetic shear on sawtooth activity in EU DEMO

“…The total driven current slightly varies between 450 kA (at s 1 = 1.5) and 420 kA (at s 1 = 3.5). This current level is well within the limit for the electron cyclotron system designed for EU DEMO, which envisages 64 gyrotrons with total power of about 130 MA [37]. The peak current drive capacity is about 60 kA/launcher according to Ref.…”

“…Note that the Gaussian perturbed current produced by electron cyclotron current drive for EU DEMO has been shown in the ref. [36]. With the perturbed current, new equilibria are self-consistently computed using the fixed boundary equilibrium solver CHEASE [37], with slight change to the total plasma current while at fixed toroidal magnetic field.…”

Structural pre-conceptual design studies for an EU DEMO equatorial EC port plug and its port integration

“…Beside the engineering baseline model 2017, the EC launcher design is made according to the physics baseline model 2018 and the latest optical system design, provided by the Italian Institute for Plasma Science and Technology (ISTP) [2], (cf. figure 2).…”

“…figure 3), where flat mirrors reflect the beams from the side where the waveguides are located towards the other side, where focusing mirrors inject then the beams through openings in the breeding blanket into the plasma. All relevant parameters of the optical system can be found in [2]. Figure 4 gives an overview on the integration of the EC launcher into the engineering baseline model.…”

“…Based on the 2017 engineering baseline, the 2018 physics baseline, and the port plugs being radially recessed to the level of the Vacuum Vessel (VV) inner shell and hence not blocking the vertical extraction of the outboard BB segments [1], a pre-conceptual design study of an EU DEMO equatorial EC launcher has been made. For optimum performance [2], the design study features a hybrid concept with MSA and also OEWG antennas. The MSA is considered for plasma stabilization and has a (partially) quasi-optical beam layout with steerable mirrors at a recessed position behind the radial extension of the breeding blankets [3].…”