As the power industry continues to change to meet new demand cycles, the daily operational profile of the steam turbine is leading to new system safety and reliability challenges. One of the most highly stressed components in the steam turbine unit is the rotor. During operation, the stress on the rotor is significant beneath the first stage turbine wheel of the high pressure and intermediate pressure steam turbine rotors. Additionally, the last stage of a low -pressure steam turbine experiences very high levels of stress. Many steam turbine rotors manufactured over 20 ears ago contain a bore machined at the centerline from which nondestructive examinations are performed. New generations of steam turbines rarely contain a machined bore. These new generation rotors still experience significant stress under the wheels and require periodic ultrasonic inspection to determine the condition of the rotor in the highest stressed regions. This paper is an introduction to a new patented inspection offering by the General Electric Company which will provide inspection coverage in the highest stressed areas of steam turbine rotors. The GE technique is a new and unique use of phased array ultrasound to provide complete volumetric inspection in the highest stressed, and often the most difficult to inspect, volume of material. The result of using the GE Un-bored Rotor Ultrasonic System (URIS™) is a composite view of the rotor volume inspection results and an inspection report highlighting potential areas of concern.

DOI: https://doi.org/10.32548.RS.2018.002

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