Scaling law for the strain dependence of the critical current in an advanced ITER Nb<sub>3</sub>Sn strand

Ilyin, Y.; Nijhuis, A.; Krooshoop, Erik

doi:10.1088/0953-2048/20/3/013

Cited by 41 publications

(23 citation statements)

References 11 publications

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“…For this purpose the critical current density behaviour of the respective superconducting material may be employed as a natural constraint. Treating the coil winding packs as single current carrying conductors, the Nb 3 Sn ITER scaling [15] -assuming constant operation temperature -can be simplified to…”

Section: Modular Coilsmentioning

confidence: 99%

HELIAS module development for systems codes

Warmer

Beidler

Dinklage

et al. 2015

Fusion Engineering and Design

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a b s t r a c tIn order to study and design next-step fusion devices such as DEMO, comprehensive systems codes are commonly employed. In this work HELIAS-specific models are proposed which are designed to be compatible with systems codes. The subsequently developed models include: a geometry model based on Fourier coefficients which can represent the complex 3-D plasma shape, a basic island divertor model which assumes diffusive cross-field transport and high radiation at the X-point, and a coil model which combines scaling aspects based on the HELIAS 5-B reactor design in combination with analytic inductance and field calculations. In addition, stellarator-specific plasma transport is discussed. A strategy is proposed which employs a predictive confinement time scaling derived from 1-D neoclassical and 3-D turbulence simulations.This paper reports on the progress of the development of the stellarator-specific models while an implementation and verification study within an existing systems code will be presented in a separate work.This approach is investigated to ultimately allow one to conduct stellarator system studies, develop design points of HELIAS burning plasma devices, and to facilitate a direct comparison between tokamak and stellarator DEMO and power plant designs.

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Section: Modular Coilsmentioning

confidence: 99%

HELIAS module development for systems codes

Warmer

Beidler

Dinklage

et al. 2015

Fusion Engineering and Design

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“…Many facilities already offer precise and thorough measurement of performances versus axial strain (helical spring [1], pacman spring [2]), bending strain (tarsis probe [3]) or contact stresses (tarsis contact stresses [4]). Our idea was to develop a setup able to test a strand in bending conditions in the limited space required for a VAMAS sampleholder.…”

Section: A General Conceptmentioning

confidence: 99%

A New Experimental Setup to Measure Critical Current in Superconducting Strands Under Periodic Bending

Torre

Ciazynski

Gros

et al. 2015

IEEE Trans. Appl. Supercond.

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Cable-in-conduit conductors made of Nb 3 Sn strands, as envisaged in high-field magnets for fusion applications (e.g., the International Thermonuclear Experimental Reactor (ITER) project), have been shown to be prone to degradation of their current transport capability when subject to high electromagnetic forces (coming from the combination of a high current and a high magnetic field), particularly under cyclic loading. Although some optimization of the cable layout can be envisaged to mitigate this effect, the knowledge of the electrical properties of Nb 3 Sn strands under periodic bending (simulating in-cable operating conditions) is generally considered a needed characteristic for magnet designers and users. The French Alternative Energies and Alternative Energies and Atomic Energy Commission (CEA)/Institute for Magnetic Fusion Research (IRFM) has developed a new Versailles Project on Advanced Materials and Standards (VAMAS)-like mandrel in order to test under relevant field and temperature conditions high-field superconducting strands subject to periodic bending provided by the strand deformation under its ownLorentz force. The advantage of this setup is its similarity with the setup used in critical current measurements on a VAMAS mandrel, which makes its implementation in existing facilities quite easy and rather cheap, as well as possible direct comparisons with unbent samples on a classical VAMAS mandrel. This paper presents the design layouts and carefully depicts the assembly of the different tested samples. The first test results obtained on Nb 3 Sn strands are given and discussed.Index Terms-Mechanical properties, Nb3Sn strands, strain dependence, test facility. 1051-8223

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“…In addition, selection of the negative c factors in the Durham scaling law may cause bad behavior for higher than ∼1.5% compressive strains. For example, the Ic versus strain sensitivity curve from the Twente measurements of the OST strands [30] is not well defined at compressive strains higher than 1.2%. As FEMCAM predicts total strains as high as 1.6%, the Summers scaling law is simpler to use.…”

Section: Transverse Lorentz Force: Bendingmentioning

confidence: 99%

Florida electro-mechanical cable model of Nb₃Sn CICCs for high-field magnet design

Zhai

Bird

2008

Supercond. Sci. Technol.

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Performance degradation of Nb 3 Sn cable-in-conduit-conductors (CICCs) is a critical issue in large-scale magnet design such as in the International Thermonuclear Experimental Reactor (ITER) and the series-connected hybrid (SCH) magnets currently under development at the National High Magnetic Field Laboratory (NHMFL). The critical current Ic of Nb 3 Sn conductors is strongly affected by thermal pre-strain in strand filaments in a CICC from differential thermal contraction between strands and conduit during cooling down after heat treatment. Mitchell and Nijhuis recently introduced strand bending under locally accumulated Lorentz force for the interpretation of observed transverse load degradation, defined as the Ic reduction due to strand bending and contact stress at strand crossing with respect to the expected Ic from strand data at the thermal compressive strain. In this paper, a new numerical model of CICC performance has been developed based upon earlier work by Mitchell and Nijhuis. The new model, called the Florida electro-mechanical cable model (FEMCAM), combines the thermal bending effects during cooling down and the electromagnetic bending effects during magnet operation, as well as effects due to strand filament fracture. We present the FEMCAM formulation and benchmark the results against about 40 conductor tests of first-cycle performance and 20 tests that include cyclic loading. We also consider the effects of different jacketing materials on CICC performance. We conclude that FEMCAM can be a helpful tool for the design of Nb 3 Sn-based CICCs and that both thermal bending and transverse bending play important roles in the performance of Nb 3 Sn CICCs.

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Scaling law for the strain dependence of the critical current in an advanced ITER Nb₃Sn strand

Cited by 41 publications

References 11 publications

HELIAS module development for systems codes

HELIAS module development for systems codes

A New Experimental Setup to Measure Critical Current in Superconducting Strands Under Periodic Bending

Florida electro-mechanical cable model of Nb₃Sn CICCs for high-field magnet design

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Scaling law for the strain dependence of the critical current in an advanced ITER Nb3Sn strand

Cited by 41 publications

References 11 publications

HELIAS module development for systems codes

HELIAS module development for systems codes

A New Experimental Setup to Measure Critical Current in Superconducting Strands Under Periodic Bending

Florida electro-mechanical cable model of Nb3Sn CICCs for high-field magnet design

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Product

Resources

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Scaling law for the strain dependence of the critical current in an advanced ITER Nb₃Sn strand

Florida electro-mechanical cable model of Nb₃Sn CICCs for high-field magnet design