Test of ITER conductors in SULTAN: An update

Bruzzone, Pierluigi; Stepanov, B.; Wesche, R.; Herzog, Robert; Calzolaio, Ciro; Vögel, Martin

doi:10.1016/j.fusengdes.2011.02.061

Cited by 16 publications

(6 citation statements)

References 10 publications

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“…Going from quasistatic mechanical stresses to operation, cyclic loading must be considered. As it hap pened for the Nb 3 Sn CICC of ITER [91], the performance degradation upon cyclic loading of large size conductors based on brittle components is an issue of paramount impor tance [92]. Delamination of the superconductor layer from the substrate is in most cases the cause of the eventual failure of REBCO tapes under load [31].…”

Section: Mechanical Stability and Fatigue Loadmentioning

confidence: 99%

High temperature superconductors for fusion magnets

Fietz²,

et al. 2018

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The commercially available high temperature superconductors (HTS) tapes and wires (BSSCO and REBCO) are introduced and the past and present projects to build fusion devices using HTS based magnets are reviewed. The main design options for high current, high field conductors are presented with the related R&D and the open issues. Depending on the material, the cable layout and the application specific needs, the challenges for HTS magnet technology are different, ranging from the anisotropic properties of the REBCO tapes, to the large volume heat treatment under high pressure for Bi-2212, to the ability to withstand the large transverse loads, to the optimization of the electrical connections for segmented coil assembly, to the ambitious target of fully demountable TF coils for tokamaks. For the generation of magnetic fields larger than 18–20 T, the HTS represents the enabling technology. The use of the expensive HTS can be better justified for applications, which are out of range for conventional, low temperature superconductors (LTS). Eventually, a roadmap for future R&D is sketched focusing on medium term technology milestones, e.g. addressing the issue of quench protection in HTS large magnets, the industrial manufacture of robust high current HTS cables and the engineering design/demonstration of demountable winding packs.

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Section: Mechanical Stability and Fatigue Loadmentioning

confidence: 99%

High temperature superconductors for fusion magnets

Fietz²,

et al. 2018

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“…From the TF samples we can see clearly that the bronze route strands BR5A/B are resistant to degradation. Figure 4 does not show the degree of stabilization of the samples after 1000 cycles but those showing stabilization include IN1C and IN2 [11,14]. BR2C and BR1C/D are among those that do not stabilize.…”

Section: Introductionmentioning

confidence: 96%

“…A further sequence of SULTAN results is also available from bronze route and internal tin ITER TF conductors [14]. The ITER TF samples are less demanding in terms of current cycles (1000) and the required minimum T cs is 5.7 K. Figure 4 summarizes the results.…”

Section: Introductionmentioning

confidence: 97%

Reversible and irreversible mechanical effects in real cable-in-conduit conductors

Mitchell

Devred

Larbalestier

et al. 2013

Supercond. Sci. Technol.

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The strong strain sensitivity of the critical properties of Nb 3 Sn is well established. However, the roles played by both the reversible strain sensitivity and the susceptibility to brittle fracture of Nb 3 Sn filaments is still leading to unexpected results and resulting design modifications of conductors. Practical conductors require acceptance of less than perfect superconducting behaviour because such conductors actually operate continuously in a slightly resistive mode. Performance testing of the ITER conductors has provided a unique database of both strand and corresponding conductor performance. The test database includes strand characterization under uniaxial and bending strain, superconducting measurements on full-size conductor samples and microscopic investigations into filament fracture. A simple mechanical and electrical model of the strands and a multistage cable (capable of operation at 12 T and 45 kA) that focuses on predicting the imperfect superconducting behaviour is used to provide insight into the processes governing the observed conductor behaviour.The conclusions show that a short twist pitch at the first cabling stage provides the best operating conditions for the strands, and further that some strand mechanical properties, essentially a high stiffness to bending and a low stiffness to pinching, increase the ability of the strands to tolerate less well optimized cables.

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“…Taking into account that the specification allows 4 nOhm DC resistance, even with the provision that the joint operate in 3.5 T peak field instead of the 1-1.5 T peak field we have in JTA, it looks as if we have a significant margin of resistance and can afford Cr on t he strands. We plan to test one more sample with the sintered joint and Cr not removed in the SULTAN facility [5] to confirm this result. If confirmed, the Cr removal operation may be omitted in sintered joint preparation.…”

Section: Hb Htmentioning

confidence: 86%

“…This method, which was based on a well-accepted practice in industry and in the applied superconductivity community, is described in the code [4]. In mid-2011, however, it was prohibited by the ITER International Organization when a s tress-accelerated corrosion in the JK2LB jacket was observed on several samples [5]. The accelerated corrosion was attributed to a miniscule presence of T halogens on the surface of the steel left from Cr stripping by acid.…”

Section: Introductionmentioning

confidence: 99%

Effect of Chrome Coating on Resistance of Sintered Joint for ITER Central Solenoid

Martovetsky

Irick

2014

IEEE Trans. Appl. Supercond.

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Abstract-The ITER Central Solenoid has 36 interpancake joints. The joints are required to have resistance below 4 nOhm at 45 kA at 4.5 K. The US ITER Project Office developed and qualified a sintered joint for the interpancake joints that consistently showed exceptionally low DC resistance of 0.13 nOhm at up to 80 kA in the self-field of about 1.5 T. To provide a good current distribution in the joint, we removed chrome plating from the strands in this area.We built and tested four samples of the sintered joints before 2012. Such a low resistance prompted an investigation of the possibility of leaving the chromium on the strands during the joint preparation and still staying well below allowable resistance. Although removal of the chrome plating is not a very labor-intensive or time-consuming operation, it requires handling of harmful fumes and produces a solution containing hexavalent Cr, which is a hazardous substance. Elimination of the Cr removal step is a simplification of the fabrication process and therefore is a desirable act. We built two identical racetrack samples of the sintered joint and tested them in our joint test apparatus. One sample had Cr removed from the strands, the other had Cr intact.This paper provides a description of the test samples, fabrication steps, and results of the DC resistance measurements. 

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Test of ITER conductors in SULTAN: An update

Cited by 16 publications

References 10 publications

High temperature superconductors for fusion magnets

High temperature superconductors for fusion magnets

Reversible and irreversible mechanical effects in real cable-in-conduit conductors

Effect of Chrome Coating on Resistance of Sintered Joint for ITER Central Solenoid

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