Inductive Brazing of Instrumented Passages of the Irradiation Device for a Nuclear Fuel Element

The paper presents a 2D finite element analysis of the inductive heating process in vacuum of the metal parts assembly located in the instrumented passage zone of the irradiation device of the B29 nuclear fuel element. The numerical computations were carried out using the professional FLUX® software which an efficient tool for solving electromagnetic and thermal field problems. The paper objective is to obtain useful information for the physical brazing process of the mentioned instrumented passages zones. The parts to be inductively heated are made of 321 stainless steel (the lower piece and the two half-ring pieces), and Inconel 600 (the W-Re thermocouple sheath). A nickel-based alloy, code BNi-9, is used as filler material in the brazing process. The metallic parts assembly of the passage area of the irradiation device for the instrumented B29 nuclear fuel element, which needs to be heated, is located inside a vacuum chamber. The induction coil is also placed within the brazing chamber. The main results obtained by numerical simulations of inductive heating process were the time evolutions of temperature map, magnetic field lines and current density map in the assembly of the workpieces. The supply frequency of the inductor coil is 8 kHz. The simulation results were used as input data for the brazing practical experiment.