Initial port integration concept for EC and NB systems in EU DEMO tokamak

Abstract The integration of the heating and current drive (HCD) systems in the EU DEMO tokamak must address a number of issues, namely space constraints in the tokamak building, remote handling requirements, breeding blanket penetration, neutron and photon radiation shielding, compliance of penetrations of the primary vacuum with safety and vacuum criteria, and a large number of loading conditions, in particular heat, electromagnetic (EM), and pressure loads in normal and off-normal conditions. A number of pre-conceptual design options for the vacuum vessel (VV) port and the port-plug are under assessment and need to be verified against all requirements and related criteria. The identification of the functional (or physics) requirements of the HCD systems remains an on-going process during the pre-conceptual design phase, hence some initial assumptions had to be made as a basis for development of the design of the VV ports and the HCD port plugs. The paper will provide an overview of present margins in the functional/physics requirements and the rationale behind the assumptions made in order to facilitate development of the pre-conceptual design options. Furthermore it will introduce the initial design concepts of the electron cyclotron (EC) Launchers and the neutral beam (NB) injectors integrated in equatorial ports. The NB duct design in DEMO and related issues such as transmission and re-ionization losses will be also addressed.

[1]  J. Morris,et al.  Overview over DEMO design integration challenges and their impact on component design concepts , 2018, Fusion Engineering and Design.

[2]  Thomas Franke,et al.  Systems engineering perspective to the integration of the heating and current drive system in the EU DEMO: Analysis of requirements and functions , 2017, Fusion Engineering and Design.

[3]  O. Sauter,et al.  Sawtooth pacing by real-time auxiliary power control in a tokamak plasma. , 2011, Physical review letters.

[4]  G. Granucci,et al.  EU DEMO transient phases: Main constraints and heating mix studies for ramp-up and ramp-down , 2017 .

[5]  T. Franke,et al.  Equatorial electron cyclotron port plug neutronic analyses for the EU DEMO , 2019, Fusion Engineering and Design.

[6]  Angel Ibarra,et al.  DEMO design activity in Europe: Progress and updates , 2018, Fusion Engineering and Design.

[7]  C. Giroud,et al.  Description of complex viewing geometries of fusion tomography diagnostics by ray-tracing. , 2018, The Review of scientific instruments.

[8]  G. Saibene,et al.  The effect of density fluctuations on electron cyclotron beam broadening and implications for ITER , 2017 .

[9]  Daniela Farina,et al.  A Quasi-Optical Beam-Tracing Code for Electron Cyclotron Absorption and Current Drive: GRAY , 2007 .

[10]  David Ward,et al.  “PROCESS”: A systems code for fusion power plants—Part 1: Physics , 2014 .

[12]  Ronald Wenninger,et al.  A stepladder approach to a tokamak fusion power plant , 2017 .

[13]  Rosaria Villari,et al.  Neutronics requirements for a DEMO fusion power plant , 2015 .

[14]  P. Vincenzi,et al.  Conceptual design of the DEMO neutral beam injectors: main developments and R&D achievements , 2017 .

[15]  John Jelonnek,et al.  EU DEMO EC system preliminary conceptual design , 2018, Fusion Engineering and Design.

[16]  X. Litaudon,et al.  Scientific and technical challenges on the road towards fusion electricity , 2017 .

[17]  Tomonori Takizuka,et al.  Power requirement for accessing the H-mode in ITER , 2008 .

[18]  John Jelonnek,et al.  Conceptual design of the EU DEMO EC-system: main developments and R&D achievements , 2017 .

[19]  Ivo Furno,et al.  Conceptual design of the beam source for the DEMO Neutral Beam Injectors , 2016 .

[20]  G. Granucci,et al.  DEMO port plug design and integration studies , 2017 .

[21]  John Jelonnek,et al.  Progress in conceptual design of EU DEMO EC system , 2017 .