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Garching bei München, Germany

Franke T.,EUROfusion Consortium | Franke T.,Max Planck Institute for Plasma Physics (Garching) | Avramidis K.,Karlsruhe Institute of Technology | Jelonnek J.,Karlsruhe Institute of Technology | And 7 more authors.
Proceedings - Symposium on Fusion Engineering | Year: 2016

Under the umbrella of the EUROfusion Consortium and within the Power Plant Physics and Technology (PPPT) Conceptual Design Activities, the project Heating and Current Drive (H&CD) conducts a number of design activities and developments for a next generation clean and environmental friendly, long pulsed (∼2 hours) Demonstration fusion power plant (DEMO). This paper covers the results of the most important state-of-The-Art and cutting edge technologies for the H&CD systems, as defined in the European Fusion Roadmap and in more detail specified in the Annual Work Plans (AWPs) in the Work-Package H&CD (WPHCD): (i) Gyrotron developments up to 240 GHz with multi-stage-depressed collector (MSDC) energy recovery for the Electron Cyclotron (EC) system; (ii) Neutral beam (NB) injector investigations with gas or alternatively photo-neutralization in the range of 25-35 MW as a modular 1 MeV injector type with reduced Cs consumption sources or alternatively volume-production based non-Cs sources; (iii) Ion Cyclotron (IC) antenna conceptual design for a distributed antenna, representing a new type of design and a transition from the commonly used port plugged antennas. © 2015 IEEE. Source

Wesche R.,Ecole Polytechnique Federale de Lausanne | Sedlak K.,Ecole Polytechnique Federale de Lausanne | Bykovsky N.,Ecole Polytechnique Federale de Lausanne | Bruzzone P.,Ecole Polytechnique Federale de Lausanne | And 2 more authors.
IEEE Transactions on Applied Superconductivity | Year: 2016

The design of the European DEMO, i.e., the future fusion tokamak planned after ITER, is being developed under the coordination of the EUROfusion Consortium. This paper reports the design optimization of the toroidal field (TF) winding pack and its corresponding react-and-wind conductor, and a new design study of the central solenoid (CS). The optimization of the TF coil is driven by the results of the mechanical analysis that revealed an unacceptable stress accumulation in some locations of the previous proposal of the TF winding pack. The design study of the CS coil is done with the aim of minimizing the outer radius, while maintaining the magnetic flux defined in the PROCESS system code. The results of the design study, namely the optimized CS coil radius, current density, hoop stress, and the field map, define the initial information that will be needed in future for designing the DEMO CS winding pack and conductor. Contrary to the former similar studies, no upper limit is set for the peak field of the CS, implicitly allowing the use of high-temperature superconductors wherever the current density of Nb3Sn at the operating field is too low. © 2002-2011 IEEE. Source

Bruzzone P.,Ecole Polytechnique Federale de Lausanne | Sedlak K.,Ecole Polytechnique Federale de Lausanne | Stepanov B.,Ecole Polytechnique Federale de Lausanne | Wesche R.,Ecole Polytechnique Federale de Lausanne | And 4 more authors.
IEEE Transactions on Applied Superconductivity | Year: 2016

The Toroidal field coils (TFC) of the EUROFusion DEMO reactor call for Nb3Sn conductor with high field and high current. Another major requirement is cost-effectiveness, to keep the ratio of investment to electric power in the same range of the competing energy sources (fission, hydro, coal, gas, etc.). The TFC proposed by the Swiss Plasma Center (SPC) is based on a double-layer Nb3Sn/NbTi winding. A react-and-wind flat cable is the core of the Nb3Sn conductor, with six grades to minimize the cost and maintain a roughly constant temperature margin of 1.5 K over the winding cross section. A short length section of the high grade Nb3Sn conductor has been manufactured using relevant industrial cabling equipment. One hundred kilograms of 1.5-mm Nb3Sn strand has been procured at WST with average Jc up to 15% higher than specified (Jc≥ 1000A/mm2 at 12 T/4.2 K). A dedicated cabling line has been set up at TRATOS cavi (Italy), producing over 350 m of dummy cable and about 13 m of superconducting cable. The assembly of the cable into a conduit by longitudinal laser welding of two steel profiles is demonstrated, including the QA procedures. A test sample has been prepared at SPC by heat treating straight sections of the cable and encasing it into a steel jacket after the heat treatment to minimize the thermal strain. The test was carried out in three test campaigns at the EDIPO facility at SPC. The test program includes Dc performance at the relevant operating conditions. An assessment of the conductor test results in terms of strand performance suggests that the applicable thermal strain is less than -0.33%. The performance is stable upon load cycles. © 2002-2011 IEEE. Source

Crofts O.,Babcock Power | Loving A.,Babcock Power | Iglesias D.,Babcock Power | Coleman M.,EUROfusion Consortium | And 5 more authors.
Fusion Engineering and Design | Year: 2015

The EU-DEMO remote maintenance strategy must be relevant for a range of in-vessel component design options. The remote maintenance project must provide an understanding of the limits of the strategy and technologies so as to inform the developing plant design of the maintenance constraints. A comprehensive set of maintenance requirements has been produced, in conjunction with the plant designers, against which design options can be assessed.The proposed maintenance solutions are based around a strategy that deploys casks above each of the vertical ports to exchange the blanket segments and at each of the divertor ports to exchange the divertor cassettes. The casks deploy remote handling equipment to open and close the vacuum vessel, remove and re-install pipework, and replace the in-vessel components.A technical design risk assessment has shown that the largest risks are common to all of the proposed solutions and that they are associated with two key issues, first; the ability to handle the large blanket and divertor components to the required positional accuracy with limited viewing and position feedback, and second; to perform rapid and reliable pipe connections, close to the blankets, with demonstrated quality that meets the safety requirements. © 2015. Source

Flammini D.,ENEA | Villari R.,ENEA | Moro F.,ENEA | Pizzuto A.,ENEA | Bachmann C.,EUROfusion Consortium
Fusion Engineering and Design | Year: 2016

The DEMO vacuum vessel, a massive water cooled double-walled steel vessel, is located behind breeding blankets and manifolds and it will be subjected to an intense neutron and photon irradiation. Therefore, a proper evaluation of the vessel nuclear heat loads is required to assure adequate cooling and, given the significant lifetime neutron fluence of DEMO, the radiation damage limit of the vessel needs to be carefully controlled. In the present work nuclear heating, radiation damage (DPA), helium production, neutron and photon fluxes have been calculated on the vacuum vessel at the inboard by means of MCNP5 using a 3D Helium Cooled Lithium Lead (HCLL) DEMO model with 1572MW of fusion power. In particular, the effect of the poloidal gap between the breeding-blanket segments on vacuum vessel nuclear loads has been estimated varying the gap width from 0 to 5cm. High values of the nuclear heating (≈1W/cm3), which might cause intense thermal stresses, were obtained in inboard equatorial zone. The effect of the poloidal gap on the nuclear heating resulted to be moderate (within 30%). The radiation damage limit of 2.75DPA on the vessel is almost met with 1cm of poloidal gap over DEMO lifetime. A comparison with Helium Cooled Pebble Bed blanket is also provided. © 2016 Davide Flammini. Source

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