Simulation Design of a Phased Array Ultrasonic Probe for Retaining Ring Inspection in Nuclear Turbine Generators

Retaining rings in turbine generators are critical components of the rotor, bearing the highest stress loads. Failure of these rings can lead to severe operational consequences. This paper presents a simulation- based design of a phased array ultrasonic probe specifically for inspecting the retaining rings of a pressurized water reactor (PWR) turbine generator rotor. Initially, stress simulation analysis was performed to identify stress concentration areas in the retaining ring under cold state conditions, considering the interference fit. Subsequently, CIVA software was utilized to calculate the acoustic field distribution in these critical regions, which informed the design of a phased array ultrasonic inspection probe. Finally, acoustic simulation was employed to validate the probe design. The simulation results demonstrate that the designed probe effectively covers the inspection area and provides adequate defect response at various axial and circumferential positions. This indicates the probe’s capability for effective defect detection with good resolution.