Present status of the high mechanical strengthened Nb3Sn superconducting wires for fusion applications

•Current status of the high mechanical strength commercial bronze processed Nb3Sn wire using several reinforcing materials was reviewed.•We have proposed the “Internal Matrix Reinforcement” as the newly high mechanical strength method without the reinforcing material for Nb3Sn wires.•The indium (In) element become the more effective solute element of Cu-Sn based ternary alloy matrix in the internal matrix reinforcement for Nb3Sn wire.