Test Results of the ITER PF Insert Conductor Short Sample in SULTAN

Bruzzone, Pierluigi; Bagnasco, M.; Bessette, D.; Ciazynski, D.; Formisano, A.; Gislon, P.; Hurd, F.; Ilyin, Y.; Martone, R.; Martovetsky, N.; Muzzi, L.; Nijhuis, A.; Rajainmäki, H.; Sborchia, C.; Stepanov, B.; Verdini, L.; Wesche, R.; Zani, L.; Zanino, Roberto; Zapretilina, E.

doi:10.1109/tasc.2005.849084

Cited by 52 publications

(68 citation statements)

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“…Further details on the coil design [6], strand and cable manufacturing [7]- [11], coil manufacturing [12], short sample test results [5], [13], and supporting analyses to the insert test [14]- [17] can be found in the extensive list of references quoted. [19], [20], with the necessary adaptations to the different operating conditions and PF conductor characteristics [15].…”

Section: The Pf Conductor Insertmentioning

confidence: 99%

“…Short sample tests in SULTAN [5] had shown that above a current threshold ranging from 38 to 45 kA, the quench current of the PFI CICC was much below the expected strand critical current. This was attributed to the combination of the magnetic and electric field gradient in the large cross section of the cable, uneven current distribution in the short sample, impressed by the joint [21], and poor current redistribution.…”

Section: The Pf Conductor Insertmentioning

confidence: 99%

“…A relatively high resistance (10 ) was observed during the test of the prototype joint in the short sample described above. This was attributed to the materials selected (CuCrZr sleeve) and joint assembly procedure (strand coating removal and soldering) in the preparation of the sample [5], [22]. Improvements in the base material conductance (by overaging at 550 the sleeves) and joint technique were expected to reduce the resistance to an acceptable value for operation, around 5 .…”

Section: The Pf Conductor Insertmentioning

confidence: 99%

“…This was attributed to the materials selected (CuCrZr sleeve) and joint assembly procedure (strand coating removal and soldering) in the preparation of the sample [5], [22]. Improvements in the base material conductance (by overaging at 550 the sleeves) and joint technique were expected to reduce the resistance to an acceptable value for operation, around 5 . The AC loss in the joint was not measured previously, nor its stability in pulsed field conditions, both factors of relevance for operation;…”

Section: The Pf Conductor Insertmentioning

confidence: 99%

“…Firstly, the cable performance must be close to the sum of the projected performance of the individual strands, without the occurrence of the premature quenches often seen in large size Nb-Ti conductors and attributed to current non-uniformity [4], [5] (see also later discussion). In practice, we quantify this first condition using the temperature margin above the operating temperature.…”

mentioning

confidence: 99%

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Test Results From the PF Conductor Insert Coil and Implications for the ITER PF System

Bessette

Bottura

Devred

et al. 2009

IEEE Trans. Appl. Supercond.

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Abstract-In this paper we report the main test results obtained on the Poloidal Field Conductor Insert coil (PFI) for the International Thermonuclear Experimental Reactor (ITER), built jointly by the EU and RF ITER parties, recently installed and tested in the CS Model Coil facility, at JAEA-Naka. During the test we (a) verified the DC and AC operating margin of the NbTi Cable-in-Conduit Conductor in conditions representative of the operation of the ITER PF coils, (b) measured the intermediate conductor joint resistance, margin and loss, and (c) measured the AC loss of the conductor and its changes once subjected to a significant number of Lorentz force cycles. We compare the results obtained to expectations from strand and cable characterization, which were studied extensively earlier. We finally discuss the implications for the ITER PF system. Index Terms-Cable-in-conduit conductors, fusion reactors, Nb-Ti superconducting material, superconducting magnets. I. BACKGROUND ON ITER PF CONDUCTORST HE ITER Poloidal Field (PF) conductors have undergone a significant evolution in the past years. In the original ITER design (2001) the Cable-in-Conduit Conductors (CICCs) were optimized to match the current/field levels in each of the six PF coils [1]. Following recent design reviews, a number of modifications have been introduced [2], leading to the conductor designs detailed in Table I, for the envelope of operating conditions in the PF Coils reported in Table II. The main change with respect to the original design is a reduction in the Cu:nonCu ratio of the low field conductors (PF2 to PF5), implying that the Stekly condition of cryogenic stability [3] is no longer respected. Experiments on subsize conductors [4] have suggested that in the planned regime of operation, and for the expected perturbation spectrum, full cryostability (i.e. a copper fraction corresponding to the Stekly limit) is excessive. In fact, for the conditions considered, it is more convenient to design the conductor for larger temperature margin, increasing the fraction of Nb-Ti, while maintaining the copper fraction to the strict minimum demanded for protection. To achieve the operating requirements of Table II, two main conditions must be met. Firstly, the cable performance must be close to the sum of the projected performance of the individual strands, without the occurrence of the premature quenches often seen in large size Nb-Ti conductors and attributed to current non-uniformity [4], [5] (see also later discussion). In practice, we quantify this first condition using the temperature margin above the operating temperature. The design value of the temperature margin is 1.5 K, with a maximum uncertainty of 0.5 K, which results in a minimum acceptable margin of 1 K.Secondly, all AC loss sources in the cable must be controlled, so to limit the temperature increase due to the heating due to the pulsed operation. In particular, the product of the cable demagnetization factor and coupling time constant, , proportional to coupling loss, must be smalle...

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