Performance assessment and optimization of the ITER toroidal field coil joints

Rolando, G.; Foussat, A.; Knaster, J.; Ilin, Y.; Nijhuis, A.

doi:10.1088/0953-2048/26/8/085004

Cited by 12 publications

(5 citation statements)

References 20 publications

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“…The CFETR TF coils provide a magnetic field around the torus to confine the plasma particles [9,20]. These coils consist of 16 TF Princeton-D coils with a plasma major radius of 5.7 m. Each TF Princeton-D coil is made of 7 double-pancake units embedded in a radial plate.…”

Section: Cfetr Coils Magnet Systemmentioning

confidence: 99%

Electromagnetic, mechanical and thermal performance analysis of the CFETR magnet system

et al. 2015

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The Chinese Fusion Engineering Test Reactor (CFETR) superconducting magnet system was designed by the National Integration Design Group for Magnetic Confinement Fusion Reactor. The CFETR magnet system consists mainly of a central solenoid (CS) coil with six modules, 16 toroidal field (TF) coils, 8 poloidal field (PF) coils, and a set of correction coils (CC). The electromagnetic stresses and stored magnetic energy are huge on the CFETR magnets since they experience both large current densities and high magnetic field. The electromagnetic, structural and thermal performance needs to be evaluated to ensure that the magnetic field, stress, and hot spot temperature of the magnet system are within the allowed criteria.The evaluation of the electromagnetic performance of the CFETR superconducting magnet system under normal operation and fault conditions was performed. The two-dimensional finite element method was adopted to analyse the stress/strain behaviour of the CFETR CS coils. In addition, the thermal-hydraulic behaviour on quench propagation performance of the CFETR CS and TF coils was analysed to evaluate the hot spot temperature of the cable and the helium pressure inside a jacket during a quench.

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Section: Cfetr Coils Magnet Systemmentioning

confidence: 99%

Electromagnetic, mechanical and thermal performance analysis of the CFETR magnet system

et al. 2015

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“…The ITER TF systems consist of 18 TF coils, each of which comprise of seven double pancakes sub-coils connected by six praying-hands joints and two shaking hands joints connected to the feeder bus bars. These joints carry 68 kA and have resistances of ∼1 nΩ to ensure the static heat dissipation is within the 5 W design limits [17,18], but use a wind and react type process so are permanent [19,20]. Techniques for making permanent joints with LTS are well established [21] and include socalled persistent joints with extremely low joint resistance (10 −13 Ω) for MRI applications [22].…”

Section: Introductionmentioning

confidence: 99%

Soldered joints—an essential component of demountable high temperature superconducting fusion magnets

Tsui

Surrey

Hampshire

2016

Supercond. Sci. Technol.

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Demountable superconducting magnet coils would offer significant benefits to commercial nuclear fusion power plants. Whether large pressed joints or large soldered joints provide the solution for demountable fusion magnets, a critical component or building block for both will be the many, smaller-scale joints that enable the supercurrent to leave the superconducting layer, cross the superconducting tape and pass into the solder that lies between the tape and the conductor that eventually provides one of the demountable surfaces. This paper considers the electrical and thermal properties of this essential component part of demountable high temperature superconducting (HTS) joints by considering the fabrication and properties of jointed HTSs consisting of a thin layer of solder (In52Sn48 or Pb38Sn62) sandwiched between two rare-earth-Ba2Cu3O7 (REBCO) second generation HTS coated conductors (CCs). The HTS joints are analysed using numerical modelling, critical current and resistivity measurements on the joints from 300 to 4.2 K in applied magnetic fields up to 12 T, as well as scanning electron microscopy studies. Our results show that the copper/silver layers significantly reduce the heating in the joints to less than a few hundred mK. When the REBCO alone is superconducting, the joint resistivity (RJ) predominantly has two sources, the solder layer and an interfacial resistivity at the REBCO/silver interface (∼25 nΩ cm2) in the as-supplied CCs which together have a very weak magnetoresistance in fields up to 12 T. We achieved excellent reproducibility in the RJ of the In52Sn48 soldered joints of better than 10% at temperatures below Tc of the REBCO layer which can be compared to variations of more than two orders of magnitude in the literature. We also show that demountable joints in fusion energy magnets are viable and need only add a few percent to the total cryogenic cost for a fusion tokamak.

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“…The DC properties including the assessment of the joint resistance are simulated with the numerical model JackPot-ACDC, at the University of Twente. The JackPot code has the ability for quantitative analysis of CICCs at a strand level precision in both stationary and transient regimes [5][6][7][8][9][10]. A twin-box joint is built in the model as an object with three subobjects consisting of two cables and a copper sole.…”

Section: Introductionmentioning

confidence: 99%

Modeling and validation of nonlinear voltage-current characteristics of ITER PF joint sample tested in the SULTAN facility

Huang

Bagni

Ilyin

et al. 2022

Supercond. Sci. Technol.

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The ITER Poloidal Field (PF) coils are wound into double pancakes with NbTi cable-in-conduit conductors, which are connected by joints in shaking hands lap-type configuration. The coils are operating in pulsed mode with a maximum operating current of 55 kA and peak magnetic field of 6.4 T, utilizing electromagnetic load on the conductors and joints. A series of PF qualification joint samples modified in praying hands configuration is measured in the SULTAN facility. For some samples, a nonlinear voltage-current (VI) characteristic is observed during the assessment of joint resistance. The growth of joint resistance versus the B×I product is larger than what is expected from the magneto-resistant copper contribution. Two non-homogeneous contact resistance models are developed and combined to quantitatively evaluate the reason for the nonlinear VI behavior in combination with the relevant power dissipation and current redistribution in the joint. The simulations reveal that, for the particular pre-qualification PFJEU2 sample with resistance variation up to 3.5 nΩ, the most probable reason for the nonlinear VI characteristic is a widely spread defective connection between copper sole and shim. The electromagnetic force involves a separation effect on the mechanically and electrically weakly connected parts, resulting into a varying resistance depending on transport current and background field. The hypothesis and models are validated by an experiment on a similar sample PFJEU3 and a post-mortem examination of the PFJEU2 sample.

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Performance assessment and optimization of the ITER toroidal field coil joints

Cited by 12 publications

References 20 publications

Electromagnetic, mechanical and thermal performance analysis of the CFETR magnet system

Electromagnetic, mechanical and thermal performance analysis of the CFETR magnet system

Soldered joints—an essential component of demountable high temperature superconducting fusion magnets

Modeling and validation of nonlinear voltage-current characteristics of ITER PF joint sample tested in the SULTAN facility

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