The vacuum induction brazing system has been developed for brazing of instrumentation feedthrough installed at high pressure and temperature boundary [I]. The instrumentation feedthrough is located in the upper part of test rig containing the coolant of pressurized water reactor operating conditions. The in-pile instruments such as thermocouples, SPND (Self Powered Neutron Detector), and LVDT (Linear Variable Differential Transformer) are installed within the test rig to monitor the coolant temperatures, the neutron fluxes, and the fuel rod pressures respectively. BNi-2 paste is used as the filler metal. The melting point and evaporation point of the BNi-2 are 970�1,040°C, and 1,100°C respectively. The sealing plug, which is the brazing target is cylindrical type with diameter 28mm and weight I18g. Figure 1 shows the vacuum induction brazing system developed in this study. It consists of a vacuum chamber including