Worldwide Benchmarking of ITER Internal Tin ${\rm Nb}_{3}{\rm Sn}$ and NbTi Strands Test Facilities

We have investigated the applied magnetic field, temperature, and self-field dependence of the critical current density of a Nb-Ti strand produced for ITER poloidal field conductor. Measurements were made on a standard ITER barrel in magnetic fields from 4.0 to 8.0 T and temperatures from 3.5 to 6.0 K. We investigated the effect of self-field by changing the direction of the transport current, resulting in an inward or outward Lorentz force acting on the strand. At 4.2 K and 5 T, the difference in the measured JC between the two Lorentz force polarities was about 1%. From this low value, we conclude that self-field effects in the Nb-Ti strand are about 40% of those expected using standard self-field calculations for fully transposed multifilamentary strands, consistent with theoretical considerations for annular filament transposition.Index Terms-Critical current, Finite element methods, Nb-Ti.

Section: Measurement Proceduresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Self-Field Effects on JC(B,T) Measurements of Nb–Ti Strands in High Magnetic Fields

Ridgeon

Raine

Lakrimi

et al. 2018

“…The sample holder with clamping contacts, which allows performing measurements of eight samples at the same time, was used. This measuring system and the measuring method successfully passed the benchmarking organized by the IO ITER [5]. Test facility details were described in our previous work [1].…”

Section: Test Facility To Measure Rrrmentioning

confidence: 99%

Residual Resistances Ratio in NbTi Strands Extracted From the ITER PF1/6 Conductor Sample After SULTAN Tests

Fetisov

Polyakova

Kaverin

et al. 2015

The residual resistance ratio (RRR) is an important parameter affecting the stability of superconductors and the quench protection properties of magnets. During the manufacture and testing of cable-in-conduit-conductors, RRR may change noticeably. Recently the RRR changes of Nb 3 Sn strands for conductors of the ITER toroidal coils have been studied during the manufacturing process, heat treatment and SULTAN testing. Here we present the similar study of RRR of Nb-Ti strands used for conductors of the ITER poloidal coils. RRRs of the strands were measured in as-received condition and at different stages of the PF conductor manufacturing. RRR of strands extracted from ITER PF conductor sample after electromagnetic and thermal cycling in the SULTAN test facility was also measured. For this purpose the strand samples were extracted from different locations in the cross-section of the PF conductor and from different positions along the axis after testing in the SULTAN. The results about the RRR change during the manufacturing process and after the SULTAN tests and also the details of experiments are presented and discussed.

“…30 m of un-reacted strand was shipped to ASIPP for the benchmarking. 1 km NbTi strand of the PF strand type S1 with 0.73 mm diameter, produced in Russia, was donated by Chepetsky Mechanical Plant for the benchmarking [4]. A micrograph of the transverse cross-section of the strand is shown in Fig.…”

Section: Samples and Sample Preparationmentioning

confidence: 99%

ITER <formula formulatype="inline"><tex Notation="TeX">$\hbox{Nb}_{3}\hbox{Sn}$</tex></formula> and NbTi Strands Benchmarking at ASIPP

Liu

et al. 2014

Self Cite

To ensure accurate and consistent measurement of the physical and superconducting properties of the Nb 3 Sn and NbTi composite strand, a strand test facility benchmarking effort for the International Thermonuclear Experimental Reactor (ITER) was initiated in August 2008. Three rounds of benchmarking have been finished. The first round was referred to as the bronze-route Nb 3 Sn strand, while the second and third benchmarking were referred to as Internal Tin Nb 3 Sn and NbTi strand, respectively. As the referenced lab of the Chinese Domestic Agency, the superconducting strand test lab from the Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP) participated in all the three rounds of benchmarking. The benchmarking includes tests for critical current (I C ), n-index, hysteresis loss, Residual Resistivity Ratio (RRR), strand diameter, Cu fraction, twist pitch (T P ), twist direction, and metal plating thickness. The results from ASIPP were acceptable except for the RRR measurements on Nb 3 Sn strands for the first and second benchmarking. Improvements have been made mainly for RRR and T P measurements, and the test reports for the third benchmarking were approved by the ITER organization. The test facility and test results were presented in this paper.