Addressing Critical Properties of Nb3Sn New Strands for ITER in Subsize Stainless Steel Jacketed Samples
The tests of the ITER model coils, which have been successfully completed in 2002, demonstrated the feasibility of the ITER coil system. They provided also the information that the Nb(3)Sn conductors were more sensitive than expected to strain, which resulted in a slightly decreased temperature margin in the project. This initiated in Europe an advanced strand procurement and qualification task to take advantage of the progresses in Nb3Sn during these last ten years. In the framework of an European task, CEA has to explore the sensitivity of these new high performance Nb3Sn strands with regard to stainless steel jacketing on subsize samples, as concern their critical properties. The scientific program and the samples associated with this task will be described in details. Using the same strand, the conductor performances will be characterized while varying cabling parameters on a set of 24 samples. These samples by the cabling, the void fraction and the stainless steel jacket thickness are representative of ITER conductors on a smaller scale. In a second step the particular sensitivity of strands coming from different suppliers will be explored. In the FBI test facility of the Forschungszentrum Karlsruhe, the critical current of these samples will be measured. The samples are about 1.2 meter long and they will be tested under field up to 14 T and at a current up to 10 kA in liquid helium at 4.2 K. They will be mechanically stretched step by step, which will release the compressive strain of the Nb3Sn induced during heat treatment. The measurement at each step of the critical current up to a maximum will unveil the initial compressive strain of the Nb3Sn and how it affects the critical properties of the conductor. The technical details of the different parts of the samples and their role in the test will be described. The fabrication in the industry has been launched and the test results of 3 prototypes will be presented.
Bibliographic Reference: An oral paper given at: 7th European Conference on Applied Superconductivity Organised by: Vienna University of Technology, Vienna (AT) Held at: Vienna University of Technology, Vienna (AT)
Availability: Available from Association EURATOM-CEA, Département de Recherches sur la Fusion Contrôlée, CEA Cadarache, F-13108 St Paul-Lez-Durance, France Tel: (+33) 4 42 25 70 01; Fax: (+33) 4 42 25 64 21 E-mail: email@example.com
Record Number: 200518354 / Last updated on: 2005-10-04
Original language: en
Available languages: en