Characterization of ${\rm Nb}_{3}{\rm Al}$ Strands Subjected to an Axial-Strain for a Fusion DEMO Reactor

Abstract

A Nb3Al 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 Nb3Al 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 Nb3Sn ITER strand and the Nb3Al Insert strand include improved strain tolerance and a higher current density at around 16 T. Performance parameters of the Nb3Al RHQT strand include 450 A/mm2 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 Nb3Al RHQT strand represents an improved performance with prospective application in the fusion DEMO reactor. In addition, the Nb3Al RHQT strand has the potential to enhance further the critical current density.