Optimization of the size and shape of the set-in nozzle for a PWR reactor pressure vessel

•The size and shape of the set-in nozzle of the RPV have been optimized.•The optimized nozzle ensure the reduction of the mass around 198 kg per nozzle.•The mass of the RPV should be minimized for better fracture toughness.

The objective of this research work is to optimize the size and shape of the set-in nozzle for a typical reactor pressure vessel (RPV) of a 300 MW pressurized water reactor. The analysis was performed by optimizing the four design variables which control the size and shape of the nozzle. These variables are inner radius of the nozzle, thickness of the nozzle, taper angle at the nozzle-cylinder intersection, and the point where taper of the nozzle starts from. It is concluded that the optimum design of the nozzle is the one that minimizes the two conflicting state variables, i.e., the stress intensity (Tresca yield criterion) and the mass of the RPV.