Garching bei München, Germany
Garching bei München, Germany

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You J.H.,Max Planck Institute for Plasma Physics (Garching) | Mazzone G.,ENEA | Bachmann C.,EUROfusion | Coccorese D.,University of Naples Federico II | And 14 more authors.
Fusion Engineering and Design | Year: 2017

Since 2014 preconceptual design activities for European DEMO divertor have been conducted as an integrated, interdisciplinary R&D effort in the framework of EUROfusion Consortium. Consisting of two subproject areas, 'Cassette' and 'Target', this divertor project has the objective to deliver a holistic preconceptual design concept together with the key technological solutions to materialize the design. In this paper, a brief overview on the recent results from the subproject 'Cassette' is presented. In this subproject, the overall cassette system is engineered based on the load analysis and specification. The preliminary studies covered multi-physical analyses of neutronic, thermal, hydraulic, electromagnetic and structural loads. In this paper, focus is put on the neutronics, thermohydraulics and electromagnetic analysis. © 2017 The Authors.

Frosi P.,ENEA | Bachmann C.,EUROfusion | Di Gironimo G.,University of Naples Federico II | Mazzone G.,ENEA | And 2 more authors.
Fusion Engineering and Design | Year: 2017

This paper refers to the activity of structural design of DEMO Divertor in the framework of the EUROfusion Consortium. The structural analysis and its preparatory assessments were carried on since a year and the first results were published in a previous paper. The Cassette Body has been examined considering the most conservatives loads (e.g. coolant pressure, volumetric nuclear heating and electro-magnetic loads) according to their latest estimates. This work is based on the design-by-analysis approach adopted in the conceptual design phase of the DEMO Divertor. This design activity has been focused on some key parameters e.g. loads, main geometric dimensions, positions of the Cassette attachments on the vacuum vessel, way of loads application to characterize the structural behavior of the Divertor Cassette. In addition to the existing 3D solid element model, a shell element model has also been developed: with this new model a parametric analysis can be done for a fast optimization. The structural assessment was done according to the Design and Construction Rules for Mechanical Components of Nuclear Installation (RCC-MRx). © 2017 Elsevier B.V.

News Article | May 4, 2017

Nuclear fusion has long held out the promise of clean, safe energy but dealing with the extremely high temperatures generated in the reactors is no easy task. Now the UK’s nuclear fusion experiment MAST Upgrade, at Culham in Oxfordshire, is to receive £21m to investigate new technology to cool the extremely hot plasma exhaust produced by the reaction. Inside a fusion reactor, light atomic nuclei are fused together to form larger ones, releasing a huge amount of energy in the process. This is achieved by confining the gas within a magnetic field and then heating it to temperatures of around 150 million Celsius, according to Dr James Harrison, Tokamak science programme delivery manager at Culham Centre for Fusion Energy. The hot fusion plasma exhaust is then passed through an area of the reactor known as a “divertor” to allow it to dissipate some of this excess heat. However, the extremely high temperatures involved mean the exhaust particles would damage the surfaces of a conventional divertor, meaning components would require regular replacement, which adds to the cost of the electricity produced. “As the super-heated gas is gradually transported away from the hot fusion producing part of the machine into the area where it is exhausted, it comes into contact with solid surfaces of either tungsten or carbon, which are typically much closer to room temperature,” said Harrison. “The super-heated plasma can heat the surfaces, leading to gradual melting or erosion of the material over time.” So the fusion researchers are investigating the use of a new “Super X” divertor, which is designed to cool particles down by sending them on a longer exhaust path out of the plasma. “The Super X divertor aims to take the exhaust plasma, which has a very high density, and expand that into a much larger volume,” said Harrison. This allows heat to be radiated away before it reaches solid material surfaces, he said. The funding, from the European fusion research consortium EUROfusion and the EPSRC, will allow the researchers to improve their understanding of plasma exhaust physics, and to carry out better predictive modelling for the proposed prototype commercial fusion power plant, known as DEMO.

Zani L.,French Atomic Energy Commission | Bayer C.M.,Karlsruhe Institute of Technology | Biancolini M.E.,University of Rome Tor Vergata | Bonifetto R.,Polytechnic University of Turin | And 41 more authors.
IEEE Transactions on Applied Superconductivity | Year: 2016

The DEMO reactor is expected to be the first application of fusion for electricity generation in the near future. To this aim, conceptual design activities are progressing in Europe (EU) under the lead of the EUROfusion Consortium in order to drive on the development of the major tokamak systems. In 2014, the activities carried out by the magnet system project team were focused on the toroidal field (TF) magnet system design and demonstrated major achievements in terms of concept proposals and of consolidated evaluations against design criteria. Several magnet system RD activities were conducted in parallel, together with broad investigations on high temperature superconductor (HTS) technologies. In this paper, we present the outcomes of the work conducted in two areas in the 2014 magnet work program: 1) the EU inductive reactor (called DEMO1) 2014 configuration (power plant operating under inductive regime) was the basis of conceptual design activities, including further optimizations; and 2) the HTS RD activities building upon the consolidated knowledge acquired over the past years. © 2016 IEEE.

Muraoka K.,Plazwire Co. | Wagner F.,Max Planck Institute for Plasma Physics (Greifswald) | Yamagata Y.,Kyushu University | Donne A.J.H.,EUROfusion
Journal of Instrumentation | Year: 2016

The accident at the Fukushima Dai-ichi nuclear power station in 2011 has caused profound effects on energy policies in Japan and worldwide. This is particularly because it occurred at the time of the growing awareness of global warming forcing measures towards decarbonised energy production, namely the use of fossil fuels has to be drastically reduced from the present level of more than 80% by 2050. A dilemma has now emerged because nuclear power, a CO2-free technology with proven large-scale energy production capability, lost confidence in many societies, especially in Japan and Germany. As a consequence, there is a world-wide effort now to expand renewable energies (REs), specifically photo-voltaic (PV) and wind power. However, the authors conjecture that PV and wind power can provide only up to a 40% share of the electricity production as long as sufficient storage is not available. Beyond this level, the technological (high grid power) and economic problems (large surplus production) grow. This is the result of the analysis of the growing use of REs in the electricity systems for Germany and Japan. The key element to overcome this situation is to develop suitable energy storage technologies. This is particularly necessary when electricity will become the main energy source because also transportation, process heat and heating, will be supplied by it. Facing the difficulty in replacing all fossil fuels in all countries with different technology standards, a rapid development of carbon capture and storage (CCS) might also be necessary. Therefore, for the short-range strategy up to 2050, all meaningful options have to be developed. For the long-range strategy beyond 2050, new energy sources (such as thermonuclear fusion, solar fuels and nuclear power - if inherently safe concepts will gain credibility of societies again), and large-scale energy storage systems based on novel concepts (such as large-capacity batteries and hydrogen) is required. It is acknowledged that the prediction of the future is difficult; therefore, the only insurance in this situation is by intensified research into all viable options. © 2016 IOP Publishing Ltd and Sissa Medialab srl.

Boccaccini L.V.,Karlsruhe Institute of Technology | Aiello G.,CEA Saclay Nuclear Research Center | Aubert J.,CEA Saclay Nuclear Research Center | Bachmann C.,EUROfusion | And 11 more authors.
Fusion Engineering and Design | Year: 2016

The design of a DEMO reactor requires the design of a blanket system suitable of reliable T production and heat extraction for electricity production. In the frame of the EUROfusion Consortium activities, the Breeding Blanket Project has been constituted in 2014 with the goal to develop concepts of Breeding Blankets for the EU PPPT DEMO; this includes an integrated design and R&D programme with the goal to select after 2020 concepts on fusion plants for the engineering phase. The design activities are presently focalized around a pool of solid and liquid breeder blanket with helium, water and PbLi cooling. Development of tritium extraction and control technology, as well manufacturing and development of solid and PbLi breeders are part of the programme. © 2016.

Vallcorba R.,CEA Saclay Nuclear Research Center | Lacroix B.,French Atomic Energy Commission | Ciazynski D.,French Atomic Energy Commission | Torre A.,French Atomic Energy Commission | And 5 more authors.
Cryogenics | Year: 2016

The future DEMO Toroidal Field (TF) magnets are likely to feature cable-in-conduit conductors (CICC) cooled by forced flow of supercritical helium. Design activities were carried out at CEA to provide a winding pack compatible with DEMO plant requirements. The CEA proposal comprises, for each of the 16 D-shaped windings, 10 double-pancakes (2×392m long) wound in 10 turns. The conductor is a square-shaped Nb3Sn double channel conductor with a central spiral, carrying a nominal current of 95.5kA. We present a thermo-hydraulic analyses focused on the central, most critical pancake, where the maximum field is reached, aiming at evaluating the integrity of the proposed conductor design. Both normal and off-normal simulations were performed using detailed electromagnetic and neutron heating load maps as input, and evaluating operational quantities such as the temperature margin in burn conditions, and the hot spot temperature in quench conditions. We assessed the sensitivity of these quantities to some driving parameters, notably mass flow rate and the choice of friction factor correlation for the temperature margin, and quench initiation features for the hot spot temperature. Furthermore, the influence of the casing cooling on the temperature margin is analyzed. The study is carried out using two thermohydraulic models. © 2016 Elsevier Ltd.

Barrett T.R.,Culham Center for Fusion Energy | Ellwood G.,Culham Center for Fusion Energy | Perez G.,Culham Center for Fusion Energy | Kovari M.,Culham Center for Fusion Energy | And 15 more authors.
Fusion Engineering and Design | Year: 2016

The European DEMO power reactor is currently under conceptual design within the EUROfusion Consortium. One of the most critical activities is the engineering of the plasma-facing components (PFCs) covering the plasma chamber wall, which must operate reliably in an extreme environment of neutron irradiation and surface heat and particle flux, while also allowing sufficient neutron transmission to the tritium breeding blankets. A systems approach using advanced numerical analysis is vital to realising viable solutions for these first wall and divertor PFCs. Here, we present the system requirements and describe bespoke thermo-mechanical and thermo-hydraulic assessment procedures which have been used as tools for design. The current first wall and divertor designs are overviewed along with supporting analyses. The PFC solutions employed will necessarily vary around the wall, depending on local conditions, and must be designed in an integrated manner by analysis and physical testing. © 2016 Thomas R. Barrett.

You J.H.,Max Planck Institute for Plasma Physics (Garching) | Visca E.,ENEA | Bachmann C.,EUROfusion | Barrett T.,Culham Center for Fusion Energy | And 11 more authors.
Nuclear Materials and Energy | Year: 2016

Recently, an integrated program of conceptual design activities for the European DEMO reactor was launched in the framework of the EUROfusion Consortium, where reliable power handling capability was identified as one of the most critical scientific as well as technological challenges for a DEMO reactor. The divertor is the key in-vessel plasma-facing component being in charge of power exhaust and removal of impurity particles. The DEMO divertor target will have to withstand extreme thermal loads where the local peak heat flux is expected to reach up to 20 MW/m2 during slow transient events in DEMO. To assure sufficient heat removal capability of the divertor target against normal and transient operational scenarios under expected cumulative neutron dose of up to 13 dpa is one of the fundamental engineering challenges imposed on target design. To develop the design of the DEMO divertor and related technologies, an R&D work package 'Divertor' has been set up in this consortium. The subproject 'Target Development' is devoted to the development of the conceptual design and the core technologies of the plasma-facing target. Devising and implementing novel structural heat sink materials (e.g. W/Cu composites) to advanced target design concepts is one of the major objectives of this subproject. In this paper, the underlying design requirements imposed by the envisaged power exhaust goal and the prominent material-design interface issues are discussed. In addition, the candidate design concepts being currently considered are presented together with the related material issues. Finally, the first results achieved so far are presented. © 2016 The Authors.

Eurofusion | Date: 2010-09-21

Drinking water.

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