Numerical simulation of critical characteristics in NbSn strand subjected to bending strain

Murakami, Haruyuki*; Ueda, Hiroshi*; Agatsuma, Ko*; Ishiyama, Atsushi*; Koizumi, Norikiyo; Okuno, Kiyoshi

In the ITER EDA, four NbSn model coils were developed and tested. In these tests, it is revealed the critical current of the conductor degrades. One of the explanations of this phenomenon is the periodic strand bending caused by enormous electromagnetic forces. We developed a simulation code to investigate dependency of the critical characteristics on bending strain. The results of the numerical simulations were in good agreement with the experiments. The general dependence of the critical current on periodic transverse load, temperature, pitch of periodic load, Ta barrier thickness, twist pitch and RRR of the bornze matrix is investigated using this simulation code.