Automated Steam Turbine Straddle Root Disc Head Inspection

Abstract

The non-destructive condition assessment of power generation steam turbines is key to ensure the power plants availability. As fossil and nuclear power plants come of age, the inspection intervals get shorter yet the inspections have to be performed with ever increasing speed and accuracy. The power industry’s answer to that challenge is the automation of these non-destructive tests using inspection robots. This paper presents a versatile inspection system that is designed to assess the condition of steam turbine blade roots, an area that is under particularly high mechanical load due to the high centrifugal forces under operating conditions. Using advanced ultrasonic sensors the system performs autonomously the whole inspection, transmitting the sensor data to a human expert who has to decide if the turbine is still fit for purpose. Reported are the inspection delivery concepts and also the basics of its ultrasonic sensors are introduced. The operational industrial robot, its limits and performances are discussed presented and discussed.