Simulation and experimental studies of induction heating during the partial upset-extrusion of a nuclear main pipe

As a large, abnormal pipe with branches, the main pipe of an AP1000 nuclear power plant is quite difficult to process integrally. To this end, researchers at Tsinghua University have proposed an integral processing method called partial upset-extrusion, which relies on high-quality online local heating. Induction heating is ideal for this purpose; however, it cannot be directly applied in the partial upset-extruding process without a thorough understanding of the heating pattern of a pipe of the desired type with a prefabricated hole. In this study, the induction heating of such a scaled abnormal pipe during the partial upset-extruding process was investigated numerically and experimentally. A coupled thermal–electromagnetic simulation was performed using the finite element method. It was shown that the prefabricated hole led to local overheating, and that this problem could be solved by placing a lid over the hole. These findings were experimentally verified using thermocouples to acquire the temperature...