Qualification tests and facilities for ITER TF Superconductors (original) (raw)

Manufacturing of the ITER TF Full Size Prototype Conductor

IEEE Transactions on Applied Superconductivity, 2000

The experience gained in the past for the ITER Toroidal Field Model Coil conductor and the results obtained so far have led to the definition of an upgraded full size prototype conductor, based on advanced Nb 3 Sn strand, and entirely manufactured in the European Union (EU). Samples for the characterisation in the Sultan facility have been prepared by Luvata (Italy) following the conductor layout defined by ITER. ENEA was responsible for conductor fabrication. Since the conductor layout was new, a full size copper dummy conductor has been preventively produced for the setting of the cabling and jacketing tools. Then, a total of four full size superconducting cables have been prepared by using Nb 3 Sn advanced strands produced by Oxford Instruments (OST) and European Advanced Superconductors (EAS), by internal tin and bronze technology, respectively. The details of manufacturing procedures will be described in this paper.

Fabrication of the First US ITER TF Conductor Sample for Qualification in SULTAN Facility

IEEE Transactions on Applied Superconductivity, 2009

A pair of 3.5 m long ITER TF size straight conductors has been fabricated into a conductor short sample and submitted to the SULTAN facility at CRPP for cold test. The sample used a triplet-based cabling pattern in one leg and a septuplet-based in the other. The legs had different cabling pattern and strand diameters, but the same void fraction. To assure the accuracy in measurement of the conductor current sharing temperature, it is important to have uniform current distribution in the cable, which requires uniformly low interstrand resistivity in the joint. In the present sample, the cable/subcable wraps and the chrome plating on all strands were removed from the cable in the termination, followed by compacting and heat treating the termination in a Glidcop sleeve. To improve current transfer, the sintered termination was further filled with soft solder before it was soldered to the copper profile. To clarify the effectiveness of short sample instrumentation, the sample was equipped with enhanced number of sensors and with sensor mounts penetrating the conductor jacket for the thermometers and voltage taps positioned in the high field zone. This paper presents the experiences in sample fabrication and instrumentation, and outlines the parameters used in the key processes.

Results of the TF conductor performance qualification samples for the ITER project

Superconductor Science and Technology, 2012

The performance of the toroidal field (TF) magnet conductors for the ITER machine are qualified by a short full-size sample (4 m) current sharing temperature (T cs ) test in the SULTAN facility at CRPP in Villigen, Switzerland, using the operating current of 68 kA and the design peak field of 11.8 T. Several samples, including at least one from each of the six ITER Domestic Agencies participating in TF conductor fabrication (China, European Union, Japan, Russia, South Korea and the United States), have been qualified by the ITER Organization after achieving T cs values of 6.0-6.9 K, after 700-1000 electromagnetic cycles. These T cs values exceed the ITER specification and enabled the industrial production of these long-lead items for the ITER tokamak to begin in each Domestic Agency. Some of these samples did not pass the qualification test. In this paper, we summarize the performance of the qualified samples, analyze the effect of strand performance on conductor performance, and discuss the details of the test results.

Methods, Accuracy and Reliability of ITER Conductor Tests in SULTAN

IEEE Transactions on Applied Superconductivity, 2000

In the last decade, a large number of high current, force flow superconductors have been tested as short length samples in the SULTAN facility. The object of the test ranged over transient stability, thermal-hydraulic behaviour, AC losses, joint resistance and proof-of-principle for innovative conductor design. Recently, with the ITER cable-in-conduit conductors (CICC), the basic DC transport properties have been the focus of the SULTAN test. The critical steps of the sample assembly and instrumentation are described, with emphasis on the application of the temperature sensors, verification of the signal treatment chain and calibration. The post-processing and the data reduction are focused on the assessment of the current sharing temperature, T cs : the conventional method of electrical field threshold detection by voltage taps is compared with the current sharing power detection by steady state gas-flow calorimetry. The longitudinal strain state of the conductors is discussed through the results of strain gauges applied on the jacket. Eventually, the value of a certified conductor test is highlighted in the frame of the quality control for the ITER magnets.

Test of ITER conductors in SULTAN: An update

Fusion Engineering and Design, 2011

The ITER Toroidal Field (TF) conductor qualification phase has been carried out by testing short sample prototype conductors in the SULTAN test facility. This phase, started in 2007, has been substantially completed after minor adjustment of the conductor specification and test procedures. All the parties involved in the TF conductor procurement passed the qualification phase. Starting 2010, the samples for TF process qualification phase are tested in SULTAN. A summary of the results for all the ITER Qualification samples and an updated statistics are presented for the V-I and V-T characteristics of the cable-inconduit conductors (CICC), including Nb 3 Sn and NbTi samples assembled with either a "bottom joint" or a "U-bend".

ITER and JT-60SA Conductor Production at ICAS

IEEE Transactions on Applied Superconductivity, 2000

The European and the Korean contributions to the ITER Project in terms of Cable-In-Conduit (CIC) conductors have been assigned to ICAS, the Italian Consortium for Applied Superconductivity. ICAS' charter members are: ENEA, with the role of general supervision and monitoring, CRIOTEC Impianti S.r.l., in charge of jacketing activities, and TRATOS Cavi S.p.A., with the duty of cable manufacturing. The ITER production consists of about 40 km of Nb 3 Sn Toroidal Field (TF) conductor and 22 km of NbTi Poloidal Field (PF) conductor, for coils 1 and 6. As part of the EU contribution to the construction of the JT-60SA Japanese Tokamak Reactor, ICAS is also in charge to produce about 28 km of NbTi TF conductor, required for the whole TF magnet system. Thanks to the high level and unique expertise available in ICAS, the consortium has been also assigned to manufacture the ITER Central Solenoid conductor samples to be tested in SULTAN for the final, positive, assessment of the updated design. In the present paper, the steps leading to the successful qualification of the main production processes will be described. What's more, the manufacturing of the first conductor unit lengths of the "production phase", i.e. the ones which will be wound to operate in the actual ITER TF and JT-60SA TF superconducting magnets, will be reported. The fabrication of the ITER CS conductor samples will be illustrated as well.

Test Results of the First US ITER TF Conductor in SULTAN

IEEE Transactions on Applied Superconductivity, 2000

The US Domestic Agency is one of six parties supplying TF cable-in-conduit conductors (CICCs) for ITER. Previous tests have shown that measured performance of the TF CICCs can be much lower than expected from the strand properties at the projected uniaxial strain and that the cabling pattern may also be an important factor. Worst of all, voltage signals well below the expected critical surface could not be reliably interpreted or canceled, making test results very suspect. The TFUS1 sample was prepared to achieve multiple goals: 1) to ensure uniform current distribution and to eliminate parasitic voltage signals by improving joints, 2) to explore the potential benefits of a different cabling pattern for better support of strain-sensitive strands, and 3) to explore the source of voltage development in the cable through the use of innovative penetrating diagnostics. Test results of the first US-made samples are presented and discussed.

Numerical Analysis of the ITER TF Conductor Samples in SULTAN With the THELMA Code

IEEE Transactions on Applied Superconductivity, 2000

The paper presents the results of a numerical analysis campaign which studies the steady-state behavior and the typical tests (current-sharing temperature and critical current measurements) foreseen for the SULTAN samples of the ITER TF reference conductor, with special emphasis to the current and electric field distribution among and along the sub-cables. In this analysis, the sample geometrical parameters (twist pitch, joint/termination length) and some electrical parameters (joint, termination and inter-bundle resistance) are supposed to range in their design or their measured boundaries, in order to understand their individual effect on the conductor performances and the test conditions.