structural assessment of tf superconducting magnet of the dtt device

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Development of a Thermal-Hydraulic Model for the European DEMO TF Coil

In the framework of the "roadmap to fusion electricity by 2050", the design of the European DEMO machine strongly relies on available technologies. The superconducting Toroidal Field (TF) magnets will be built using available Low Temperature Superconducting (LTS) strands; the ENEA Winding Pack (WP) proposal will exploit graded layer-wound rectangular conductors, whose design is ongoing. The WP will be encapsulated in a stainless steel casing, whose cooling has not been designed yet. In this paper, we present the thermal-hydraulic (TH) model of an entire TF coil for the European demonstration power plant DEMO. Two cooling options are proposed and investigated for the casing, while for the WP the ENEA design, with multiple low impedance hydraulic channels, is considered. The thermal coupling between WP and casing is parametrically included in the model. The TH behavior of a TF coil (WP + casing) during a plasma burn is presented and discussed, comparing the two cooling options of the casing

Structural assessment of TF superconducting magnet of the DTT device

The paper presents the multi-physics study of the Toroidal Field (TF) coils of the DTT device, as defined according to the design of the “Divertor Tokamak Test facility Interim Design Report” also known as the “green book”. TF coils winding packs are constituted by 5 Double-Pancakes (DP), enclosed into a SS316LN casing for structural reinforcement. The conductor design is based on a 0.82 mm Nb3Sn strand similar to what already produced for the ITER TF coils. The structural assessment has been performed for the Single Null (SN) reference scenario, adopting Ansys® Workbench™ as numerical tool. Electromagnetic load has been evaluated by calculating with the TOSCA® code the magnetic field components on a cloud of points within the TF winding pack. The pointwise information on Lorentz density of forces has been then transferred onto the FEA mesh using the software embedded interpolation tool. The 3D FEM analysis of the TF coil has been accomplished considering the Winding Pack (WP) as a homogeneous body. The steel casing was the object of the stress assessment, evaluated along a path through the most critical location on the equatorial cross section

Structural Assessment of the DTT Poloidal Field Coil System

In the context of the European fusion roadmap, the divertor tokamak test (DTT) experimental reactor is intended to investigate alternative divertor configurations in view of the EU-DEMO power exhaust handling necessities. The six poloidal field coils of this tokamak are responsible for the plasma shape and equilibrium, and numerous steps were taken to obtain a design that is magnetically consistent with plasma requirements and structurally compliant with the chosen failure criterion. This work presents the structural assessment that has been performed on the poloidal coil system, taking into account the cooldown process, the energisation to operating conditions and fatigue. Finite Element Analysis has been employed as the principal means of investigation

Test Results of Three Poloidal Field Superconducting Samples in SULTAN

Superconductors for the ITER Poloidal Field Coils are large cable-in-conduit conductors (CICC) made of NbTi strands encased in a round-in-square stainless steel jacket. Three prototype conductor sections for poloidal field coils PF1/6, PF2/3/4 and PF5 have been fabricated in collaboration of the domestic RF, CN and EU agencies and tested in SULTAN Test Facility at the nominal operating conditions. The test aimed to characterize the DC and AC behavior of the conductors. The DC test was focused on the current sharing temperature (T-cs) at the nominal operating current and nominal operating background field. The take-off electric field at the nominal Helium mass flow rate was investigated versus the cable current density over a broad range of field and temperature. The AC loss measurement was performed before any electromagnetic loading and after a number of load cycles in order to define the impact of cyclic loads on the coupling currents constant of the cable. From the test results in SULTAN test facility, the margins in normal operation and the limits of the operation range of the ITER PF conductors are assessed

Performance analysis of a graded winding pack design for the EU DEMO TF coil in normal and off-normal conditions

The superconducting magnet system plays an important role in the framework of the design of the EU DEMO tokamak. In recent years, ENEA developed a prototype of cable-in-conduit conductor (CICC) with two low-impedance central channels to be used in the DEMO Toroidal Field (TF) coils with a graded winding pack (WP). In this paper, a model of a TF coil based on the thermal-hydraulic code 4C has been developed, including the WP, the steel casing with dedicated cooling channels (CCCs) and the two independent cryogenic circuits cooling the WP and the casing, respectively. The first part of the work analyzes the performance of the WP during a series of standard plasma pulses in normal operating conditions. In the second part different off-normal operating conditions during the plasma pulses are studied, namely the collapse of one or both central channel(s) in the most critical CICCs and the plugging of some CCCs at the most critical locations in the magnet

Conceptual Design Report - A 250 GHz Radio Frequency CARM Source for Plasma Fusion

The book presents the conceptual design for a Cyclotron Auto Resonance Maser source, operating at 250 GHz and conceived for Plasma Fusion research activities. The study is aimed at planning the construction of such a device at the ENEA Frascati Center, within the framework of the researches pertaining to the nuclear fusion. This foreseen activity gathers together different skills traditionally present in ENEA and including nuclear fusion, accelerator technology, beam handling and transport, superconductivity. The report covers the different details of the project and is divided in two parts. The first contains a general description of the entire system, furthermore it describes the motivations underlying the choice of the device, the relevant theoretical foundations, the reasons for the choice of the operating parameters and the expected performances of the source. In the second part the project details are reported and each constituting item is properly described in the technical annexes: the cathode design and the electron beam shaping and transport; the power supply and electrical pulse forming line; the Superconducting magnet and CARM cavity characteristics; the code development effort for the analysis of the radiation output performances