JT-60SA is a fusion experiment, which is jointly constructed by Japan and Europe and which shall contribute to the early realization of fusion energy, by providing support to the operation of ITER and by addressing key physics issues for ITER and DEMO. The 18 superconducting toroidal field (TF) coils of the JT-60SA device will be provided by the European laboratories ENEA and CEA and tested in a cold test facility (CTF) at CEA Saclay. The coils will be cooled with supercritical helium and tested at the nominal current of 25.7 kA, at temperatures between 5 and 7.5 K, to check the temperature margin against a quench. The main objective of these tests is to validate the TF coil performance and hence mitigate fabrication risks. During the CTF commissioning phase, the cooling down and warming up capacities have been checked, the main thermal and hydraulic performances of the cryogenic loop have been measured, and the electrical circuit including the magnet safety system has been tested in quench conditions. This paper will give an overview of the main results from the commissioning tests of the CTF.

JT-60SA is a fusion experiment which is jointly constructed by Japan and Europe and which shall contribute to the early realization of fusion energy, by providing support to the operation of ITER, and by addressing key physics issues for ITER and DEMO. In order to achieve these goals, the existing JT-60U experiment will be upgraded to JT-60SA by using superconducting coils. The 18 TF coils of the JT-60SA device will be provided by European industry and tested in a Cold Test Facility (CTF) at CEA Saclay. The coils will be tested at the nominal current of 25.7 kA and will be cooled with supercritical helium between 5 K and 7.5 K to check the temperature margin against a quench. The main objective of these tests is to check the TF coils performance and hence mitigate the fabrication risks. The most important components of the facility are: a 11.5 m x 6.5 m large cryostat in which the TF coils will be thermally insulated by vacuum; a 500 W helium refrigerator and a valve box to cool the coils down to 5 K and circulate 24 g/s of supercritical helium through the winding pack and through the casing; a power supply and HTS current leads to energize the coil; the control and instrumentation equipment (sensors, PLC's, supervision system, fast data acquisition system, etc.) and the Magnet Safety System (MSS) that protects the coils in case of quench. The paper will give an overview of the design of this large facility and the status of its realization. (C) 2015 Elsevier B.V. All rights reserved.

An ATLAS Barrel Toroid conductor was tested in the Saclay High Current Test Facility. The conductor is a Nb-Ti Rutherford cable imbedded in a high purity aluminum stabilizer. The conductor's width was reduced from 57 mm to 30 mm in order to be able to use an existing sample holder. We tried to measure the critical current in background fields of up to 3 T. The field was produced by a 0.8 m long superconducting dipole magnet. The test station was equipped with a superconducting transformer transferring maximum primary and secondary currents of respectively 174 A and 80 kA. The secondary current was measured with flux coils and with a superconducting Direct Control Current Transducer (DCCT), a modified version of the "Macc+" 600 A commercial DCCT from Hitec, which was operated at currents of up to 57 kA. This paper reports on the performance of the test station, on the results of the quench current measurements performed on the stabilized ATLAS conductor and on the difficulties to measure the critical current of an aluminum stabilizer conductor.

In the framework of the Iseult/Inumac project, the development of a 500 MHz whole body MRI magnet has been launched in 2006. This magnet has outstanding specifications compared to standard MRI systems in that the central field is 11.7 T with a warm bore of 900 mm. This magnet will operate in driven mode, i.e. the magnet is permanently connected to a power supply. As the field stability needed for MRI imaging requires a field drift of less than 0.05 ppm/h, it is hardly feasible to directly transpose this requirements in the power supply specification. As a first step, existing solutions for other applications have been found in literature. Two of them have been selected as potentially applicable to our project: one using a semi-persistent mode, and the other one using a short-circuited superconducting coil in the inner bore. For each solution, an experimental assessment has been done on a very small 7 T magnet. The objectives of these tests are to get some experimental inputs for the achievable stability in order to design and to build reduced scale prototype of components required to apply these stabilization methods on the full scale magnet. We will present the results of the two stabilization methods and their extrapolations.