2nd International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurized Components, New Orleans May 2000.

TABLE OF CONTENTS

Benefits of Ultrasonic Phased Arrays Beam Angle Control Focal Distance Control Echo Signal Processing Dynamic Depth Focusing (DDF) Conventional Focusing vs. Dynamic Depth Focusing High-Speed Weld Inspection Weld Inspection Weld Inspection - Seeing Is Believing Weld Inspection Seam-Welded High Energy Piping Complex Shape Inspection Turbine Dove Tail Inspection Turbine Blade Root Inspection Complex Shapes Inspection Tube Inspection High-Speed Corrosion Mapping of HX Tubes Phased Array Transmitter/Receiver Side-by-Side L Wave (TRL) Probes Conclusion References

Benefits of Ultrasonic Phased Arrays

• Phased arrays allow real-time control of three important ultrasonic probe parameters
  • Focal distance: continuously and dynamically adjustable
  • Beam angle: continuously and dynamically adjustable
  • Focal spot size: dynamically adjustable
• Extra benefit
  • Multiplexing allows fast displacement of ultrasonic beam within probe
• Main benefits of ultrasonic phased arrays
  • High-speed inspection using single-axis scans instead of conventional raster scan
  • Near-optimal focal length and focal spot for various areas of complex parts or thick components
  • Small, simple probe assembly with multiple beams from a single probe
  • Easy-to-install, low-cost, one-axis scanning systems
  • Better detection in austenitic materials and dissimilar metal (DM) welds
  • Reduced time exposure to radiations

Beam Angle Control

• Pulsing multiple elements in parallel is the same as firing a single, large element
• Adding suitable delays is the same as increasing travel path or using a wedge; thus affecting the beam angle
• Multiple beam angles can be sequentially generated from a single probe, providing exceptional flexibility

Focal Distance Control

• Phased arrays use delays on received waveforms before summing, so that contributions from a selected area add up
• Signals from other areas do not add up to a larger signal

Echo Signal Processing

• Phased arrays use delays on received waveforms before summing, so that contributions from a selected area add up
• Signals from other areas do not add up to a larger signal

Dynamic Depth Focusing (DDF)

• Single probe with DDF replaces multiple probes with different focal lengths; less probes means simplified probe pan assembly
• Single pulse provides inspection of the total depth with near-optimal focus
• DDF speeds up overall inspection

Conventional Focusing vs. Dynamic Depth Focusing

High-Speed Weld Inspection

• Pipe welds
• Pressure vessel welds
• High energy piping

Weld Inspection

• High-speed, single-axis scans with motorized or manual scanners
• Multiple angles may be generated by the same probe
• Multiplexing allows a single-axis scan, which is faster than a typical raster scan
• Optimal focusing throughout the complete thickness
• Can be used for inspection of pipe and pressure vessel welds

Weld Inspection - Seeing Is Believing

• Pipeline weld inspection (two probes only)
  1. Installation
  2. Scan (100 mm/s)
  3. Scanner removal
  4. Move to next weld
Total time: 1:07 min.
Including installation and removal!
How long would it take with the raster scan technique?

Typical results from PipeWIZARD PA

Weld Inspection

• Automatic configuration using pre-defined weld profiles
• Easily adapted to different weld profiles, part thickness, and code requirements
• Simplified, dedicated user interface
• Automatic calibration
• Multichannel, real-time display
• Color-coded, on-line data validation
• Light, single-axis scanner
• Reduced manpower
• Increased speed Inspection of 10-m diameter PV in 30 minutes How long would it take with the raster scan technique?

  Pulse Echo 3D Imaging

• PV weld, 2-inch wall (50 mm), 10 to 35 inches in diameter (3 to 10 m)
• Pulse echo (0, 45, 60 degrees) and TOFD
• Real-time imaging (A-, B-, C-scan, and TOFD)
• Inspection speed of 20 mm/s
Inspection of 10-m diameter PV in 30 minutes
How long would it take with the raster scan technique?

Seam-Welded High Energy Piping

• Goal
  • Detect, size, and characterize creep damage
• Conventional techniques
  • Screening scan using TOFD followed by slow, high-resolution raster scan with focalized beam
  • Considerably time-consuming
  • Data difficult to interpret
• Phased array benefits
  • Complete weld coverage with multiple beam angles, in a single pass
  • Much faster
  • Simpler, more consistent and effective analysis
  • Accurate flaw sizing without collecting additional data Weld Base Material Creep Cracking Near Side OD Near Side ID Far Side OD Far Side ID Phased Array Search Unit Weld

Complex Shape Inspection

• Turbine Dove Tail
• Turbine Blade Root
• Turbine Disk

Turbine Dove Tail Inspection

• Computer-controlled beam angle and focal distance
• Single scan to inspect all three hooks
• Successfully used at Duane Arnold and Palo Verde power plants for inspection of GE-type dovetails

Turbine Blade Root Inspection

• Goal
  • Ultrasonic inspection of ABB-type turbine blade root area
• Phased array benefits
  • Blade remains installed on disk during inspection
  • No need to remove, reinstall, or balance
  • Very fast: 4 blades inspected at a time Technique #2 - from top Technique #3 : from the wing Technique # 1: From side

Complex Shapes Inspection

• Multiple beam angles from single probe
• Optimal focus
• Simplified probe pan assembly, where one probe is used instead of many
• Fast, single-pass inspection of complex geometries
• Typical applications:
  • Turbine disks
  • Blade roots and attachments
  • RPV penetrations
  • RPV nozzle welds
Sectorial scan Ultrasonic beams

Tube Inspection

High-Speed Corrosion Mapping of HX Tubes

• Circular phased array probe with 80 elements
• 160 pulses per turn (2.25-degree resolution)
• Multiplexing allows ultrasonic beam rotation at up to 19,000 r/min
• High-speed, high-resolution inspection without mechanical rotation!

• 3 flat-bottom holes
  • 5 mm in diameter, 0.5 mm deep, 1 and 2 mm spacing
  • 3 mm in diameter, 0.25 mm deep, 1 and 2 mm spacing
  • 1.5 mm in diameter, 0.25 mm deep, 1 and 2 mm spacing
  • 320 mm/s with 1 mm pitch or 50 mm/s with 0.3 mm pitch

Phased Array Transmitter/Receiver Side-by-Side L Wave (TRL) Probes

• Phased array extends the working range of TRL technique: multiple angles and focal distances using only one probe pair
  • Under cladding crack detection in dissimilar metal (DM) welds
    • Phased array allows inspection with range of angle ensuring optimal reflection
  • Austenitic welds and cast stainless steel
    • Phased array enhances flaw detection in cast stainless steel through optimal angle and focus setting
    • Phased array with dynamic depth focusing produce optimal focuses throughout a wide depth range

Conclusion

• Main benefits of phased arrays
  • High-speed inspection using single-axis scans instead of conventional raster scan
  • Near-optimal focal length and focal spot for various areas of complex parts or thick components
  • Small, simple probe assembly with multiple beams from a single probe
  • Easy-to-install, low-cost, one-axis scanning systems
  • Better detection in austenitic materials and dissimilar metal (DM) welds
  • Reduced time exposure to radiations

References

1. Phased Array Ultrasonic Examination of BWR Core Shroud; J. Hayden, P. Johnson, (GE); G. Selby, S. Romano (EPRI); EPRI Phased Array Inspection Seminar, 98/09, Portland, Maine
2. Steam Turbide Blade Attachment Inspection using Linear Phased Array Ultrasonic Technology; P. Sabourin, G. Selby (EPRI); D. Lessard (GE); EPRI Phased Array Inspection Seminar, 98/09, Portland, Maine
3. Dynamic Focusing of Phased Array for Nondestructive testing : Characterization and Application; A. Lamarre, F. Mainguy (R/D Tech); EPRI Phased Array Inspection Seminar, 98/09, Portland, Maine
4. Feasibility and Benefits of Phased-Array Technology for RPV Clad-to-Base Metal Examinations from the outside Surface.; L. Becker, T. Kimball, M. Dennis (EPRI); EPRI Phased Array Inspection Seminar, 98/09, Portland, Maine
5. Feasibility Study of Ultrasonic Inspection using Phased-Array of Turbine Blade Root , Rotor Steeple Grooves and Rotor Steeple; P. Ciorau, D. MCGuillivray (Ontario Hydro); A. Lamarre, F. Jacques (R/D Tech); EPRI Phased Array Inspection Seminar, 98/09, Portland, Maine
6. Evaluation of Phased Array Ultrasonic Probe for Tube Inspection ; M. Key (Framatome Technologies); J. Quinn (Westinghouse Electric); EPRI Phased Array Inspection Seminar, 98/09, Portland, Maine
7. Circular Phased Arrays for the Inspection of Superphoenix Steam Generator tubes; G. Fleury, J. Poguet (Imasonic SA); O. Burat, G. Morea (Framatome); EPRI Phased Array Inspection Seminar, 98/09, Portland, Maine
8. Examination of Seam-Welded High Energy Piping using linear Phased array techniques; Jeff Landrum, EPRI; EPRI 5th Piping & Bolting Inspection Conference; June 23-25, 1999; San Antonio, TX
9. Design and Application of Low-Frequency Twin Side-by-Side Phased Array Transducers for Improved UT Capability on Cast Stainless Steel Components; M. Dalaide, G. Maes, et. al.; 2nd Int'l Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurized Components
10. Phased Array Examination of Seam-Welded High Energy Piping; J. Landrum; 2nd Int'l Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurized Components

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