Search results for "PLASMA"
showing 10 items of 4043 documents
Divertor of the European DEMO: Engineering and technologies for power exhaust
2022
International audience; In a power plant scale fusion reactor, a huge amount of thermal power produced by the fusion reaction and external heating must be exhausted through the narrow area of the divertor targets. The targets must withstand the intense bombardment of the diverted particles where high heat fluxes are generated and erosion takes place on the surface. A considerable amount of volumetric nuclear heating power must also be exhausted. To cope with such an unprecedented power exhaust challenge, a highly efficient cooling capacity is required. Furthermore, the divertor must fulfill other critical functions such as nuclear shielding and channeling (and compression) of exhaust gas fo…
Overview of first Wendelstein 7-X high-performance operation
2019
Abstract The optimized superconducting stellarator device Wendelstein 7-X (with major radius , minor radius , and plasma volume) restarted operation after the assembly of a graphite heat shield and 10 inertially cooled island divertor modules. This paper reports on the results from the first high-performance plasma operation. Glow discharge conditioning and ECRH conditioning discharges in helium turned out to be important for density and edge radiation control. Plasma densities of with central electron temperatures were routinely achieved with hydrogen gas fueling, frequently terminated by a radiative collapse. In a first stage, plasma densities up to were reached with hydrogen pellet injec…
Preliminary thermal-hydraulic analysis of the EU-DEMO Helium-Cooled Pebble Bed fusion reactor by using the RELAP5-3D system code
2021
Abstract In the frame of the activities promoted and encouraged by the EUROfusion Consortium aimed at developing the EU-DEMO fusion reactor, great emphasis has been placed at a very early stage of the design to incorporate the provisions needed to improve the overall plant safety and reliability performances as well as to analyse possible mitigation actions. In this framework, the research activity has been focused on the representative and safety relevant cooling loop of the Helium Cooled Pebble Bed (HCPB) Breeding Blanket (BB) Primary Heat Transfer System (PHTS), purposely selected by the safety team, in order to assess its thermal-hydraulic behaviour during normal operational conditions …
Hydraulic Characterization of the Full Scale Mock-Up of the DEMO Divertor Outer Vertical Target
2021
In the frame of the pre-conceptual design activities of the DEMO work package DIV-1 “Divertor Cassette Design and Integration” of the EUROfusion program, a mock-up of the divertor outer vertical target (OVT) was built, mainly in order to: (i) demonstrate the technical feasibility of manufacturing procedures; (ii) verify the hydraulic design and its capability to ensure a uniform and proper cooling for the plasma facing units (PFUs) with an acceptable pressure drop; and (iii) experimentally validate the computational fluid-dynamic (CFD) model developed by the University of Palermo. In this context, a research campaign was jointly carried out by the University of Palermo and ENEA to experimen…
Systems Engineering approach in support to the breeding blanket design
2019
Abstract Nowadays the Systems Engineering (SE) methodology is applied in several fields of engineering and it represents a powerful interdisciplinary means to enable the realisation of complex systems taking into account the customer and Stakeholder´s needs. Also in the fusion community, this theme is becoming increasingly pressing and the implementation of the SE approach, from the early stage of design, is now a must. Indeed, within the framework of EUROfusion activities, SE method has been selected for capturing the system and interface requirements and for their management and verification with particular focus to the Breeding Blanket (BB) System of the European Demonstration Fusion Pow…
Studies on Flat Sandwich-type Self-Powered Detectors for Flux Measurements in ITER Test Blanket Modules
2018
Neutron and gamma flux measurements in designated positions in the test blanket modules (TBM) of ITER will be important tasks during ITER’s campaigns. As part of the ongoing task on development of nuclear instrumentation for application in European ITER TBMs, experimental investigations on self-powered detectors (SPD) are undertaken. This paper reports the findings of neutron and photon irradiation tests performed with a test SPD in flat sandwich-like geometry. Whereas both neutrons and gammas can be detected with appropriate optimization of geometries, materials and sizes of the components, the present sandwich-like design is more sensitive to gammas than 14 MeV neutrons. Range of SPD curr…
Identification of blanket design points using an integrated multi-physics approach
2017
Abstract The breeding blanket (BB) is one of the key components for a fusion reactor. It is expected to sustain and remove considerable heat loads due to the heat flux coming from the plasma and the nuclear power deposited by the fusion neutrons. In the design of the BB, the engineering requirements of nuclear, material and safety kind are involved. In the European DEMO project, several efforts are dedicated to the development of an integrated simulation-design tool able to perform a multi-physics analysis, allowing the characterisation of BB design points which are consistent from the neutronic, thermal-hydraulic and thermo-mechanical point of view. Furthermore, at Karlsruhe Institute of T…
Integrated design of breeding blanket and ancillary systems related to the use of helium or water as a coolant and impact on the overall plant design
2021
Currently, for the EU DEMO, two Breeding Blankets (BBs) have been selected as potential candidates for the integration in the reactor. They are the Water Cooled Lithium Lead and the Helium Cooled Pebble Bed BB concepts. The two BB variants together with the associated ancillary systems drive the design of the overall plant. Therefore, a holistic investigation of integration issues derived by the BB and the installation of its ancillary systems has been performed. The issues related to the water activation due to the 16N and 17N isotopes and the impact on the primary heat transfer systems have been investigated providing guidelines and dedicated solution for the integration of safety devices…
The DEMO water-cooled lead–lithium breeding blanket: design status at the end of the pre-conceptual design phase
2021
The Water-Cooled Lead–Lithium Breeding Blanket (WCLL BB) is one of the two blanket concept candidates to become the driver blanket of the EU-DEMO reactor. The design was enacted with a holistic approach. The influence that neutronics, thermal-hydraulics (TH), thermo-mechanics (TM) and magneto-hydro-dynamics (MHD) may have on the design were considered at the same time. This new approach allowed for the design team to create a WCLL BB layout that is able to comply with different foreseen requirements in terms of integration, tritium self-sufficiency, and TH and TM needs. In this paper, the rationale behind the design choices and the main characteristics of the WCLL BB needed for the EU-DEMO …
Structural assessment of a whole toroidal sector of the HELIAS 5-B breeding blanket
2021
Abstract The European roadmap for the realization of fusion energy considers the stellarator line as a possible long-term alternative to a tokamak DEMO. In this context, from the plasma physics standpoint, the most promising option is a five-field period power plant called HELIcal-axis Advanced Stellarator (HELIAS) 5-B. In order to allow the electricity production, the HELIAS 5-B reactor must be endowed with a breeding blanket (BB). Hence, in this paper, the advancements in the HELIAS 5-B BB design are reported. In particular, the structural assessment of a whole BB period, extending along toroidal direction for 72 °, is depicted. A geometric configuration encompassing dummy BB segments has…