Fabrication of MgB 2 superconducting wires as low activation superconducting materials for an advanced fusion reactor application

Abstract

Magnesium diboride (MgB 2) superconducting wires are interesting as alternative conductor of Nb-based superconducting wire applying for the advanced nuclear fusion reactor from viewpoint of decay time of induced radioactivity. However, J c property of MgB 2 wire is insufficient for alternative material of Nb-based superconductor, and it is necessary to improve further J c property. In order to improve J c property, we tried to fabricate the several trace amounts of Cu addition MgB 2/Fe-sheathed wires through PIT process using Mg 2Cu as Cu addition source. T c values of Cu addition samples were higher than those of non-Cu addition samples and they were improved with increasing amount of Cu addition. On the other hand, core J c value were decreased with increasing amount of Cu addition and the maximum core J c values were estimated to be over 100 A/mm 2 at 4.2 K under 8 T for 1 and 3 at% Cu addition sample.