Characterization of Strands Subjected to an Axial-Strain for a Fusion DEMO Reactor

• Published in: IEEE transactions on applied superconductivity 2009-06, Vol.19 (3), p.1540-1543
• Main Authors: Hemmi, T., Koizumi, N., Nunoya, Y., Okui, Y., Matsui, K., Nabara, Y., Isono, T., Takahashi, Y., Okuno, K., Banno, N., Kikuchi, A., Iijima, Y., Takeuchi, T.
• Format: Article
• Language: English
• Subjects: Annealing; Capacitive sensors; Collaboration; Conductors; Critical current; Critical current density; Current density; Fusion DEMO reactor; Inductors; Niobium; strain; superconductor; Tin; {\rm Nb}_{3}{\rm Al}
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2009.2018237

A Nb 3 Al strand, produced by the ldquorapid-heating, quenching and transformation annealing (RHQT)rdquo process, has been developed in collaboration between JAEA and NIMS aiming at application to the conductor in a fusion DEMO reactor. A detailed description of critical current characteristics of the Nb 3 Al RHQT strand may assist in predicting accurate conductor performance. Calculations of the critical current density are adjusted to 5 scaling laws. Advantages of the newly developed strand compared to the Nb 3 Sn ITER strand and the Nb 3 Al Insert strand include improved strain tolerance and a higher current density at around 16 T. Performance parameters of the Nb 3 Al RHQT strand include 450 A/mm 2 at 15.9 T, 5.7 K and -0.4%. These performance parameters fulfill the requirements of the TF conductor of the fusion DEMO reactor. Therefore, the Nb 3 Al RHQT strand represents an improved performance with prospective application in the fusion DEMO reactor. In addition, the Nb 3 Al RHQT strand has the potential to enhance further the critical current density.