Induction Heating Numerical Study for Brazing Upper Plug Passages of an Instrumented Alfred Fuel Element Irradiation Device

This paper presents the numerical study of the induction heating process at high temperatures in vacuum of the metal parts assembly from upper plug instrumented passes area of an irradiation experimental device of instrumented ALFRED nuclear fuel element. This irradiation device is proposed for irradiation tests in the INR TRIGA-SSR reactor. The metallic materials considered for the parts of interest such as the thermocouple sheath and upper plug for which the inductive heating will be simulated are Inconel 600 austenitic stainless steel and BNi-9 for the brazing filler alloy. The simulation results will be useful for the physical brazing process based on the induction heating technique of the instrumented passes of the ALFRED fuel element experimental irradiation device. The goal of the process will be to obtain sealed brazed passes between the thermocouple sheath and the inner cylindrical wall of the passes hole through the upper plug, using BNi-9 alloy. The numerical model of the inductive device contains a tubular quartz glass vacuum chamber, which comprises the parts assembly for induction heating and the inductor coil outside the vacuum enclosure. The numerical analysis of the induction heating process have been performed using FLUX2D® software package based on the finite element method. The numerical simulations allowed us to determine the maps with the time evolution of the magnetic flux density and current density, as well as the temperature in the heated parts assembly.