Adapting Eddy Current Array Technology for NDT Inspections
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Agenda
• Eddy Current Array Technology
• Why Eddy Current Arrays?
• HX Solution – CXB
• Surface Solution – Surface Array Flex Probe
• Encircling Solution - RCCA
• Eddy Current Engineered to Order (ETO)
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Eddy Current Array Technology
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• Instrument improvements enable use of ECAs
• Large number of small coils
• High sensitivity and wide coverage
• Probe shapes conform to complex surfaces
• Enable inspection in tight access areas
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Eddy Current Arrays (ECA)
Individual coils
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ECA System Components
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MIZ®-200 InstrumentSurface Array Flex Probe
Velocity® Software
Why Eddy Current Arrays?
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• Augment or replace PT and MT– Reduced inspection time - data acquisition is fast and easy
– Does not require surface preparation
– Does not create a dirty environment that needs cleaning
– Enables flaw sizing
– Inspections are digitally recorded for archiving and historical comparison
– Improved flaw detection and sizing with C-scan imaging
• Complement UT– Sensitive to surface flaws which are in the ultrasonic “dead zone”
• Couple with an auto-analysis system
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Why Eddy Current Technology?
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Why Eddy Current Arrays?• Fast inspection
• Improved probability of detection
• Accurate defect positioning using encoded data
• Reliable results from better stability during the inspection
• C-scan imaging for quick and easy data analysis
• Coil configurations for various applications
Single coil: slow n coils: n times faster
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HX Solution - CXB
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• Circumferential cracking
• Cracking in the expansion areas
• Close proximity pitting
• Stress corrosion cracking
• Bobbin signals require further characterization
• Mixed-mode signals and complex defects
Inspection Challenges in HX Tubing
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• Array and bobbin coils in one probe
• Leverages proprietary X-Probe™ technology developed for highest reliability steam generator inspections
• Bobbin coils provide general detection
• Array coils provide axial and circumferential flaw detection and characterization
• Titanium body for long probe life
CXB Tubing Array Probe
Array coils
Bobbin coils
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• Bobbin inspection speeds
• Single pass inspection
• Array probe resolution
• Complementary inspection methods
• Reduce false positives
Why CXB?
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• Application– Turbine Generator Condenser Inspection
• Challenge– Multiple tube leaks were causing condensers to be taken off line
– Dual tube sheet structures with multiple expansions
– Tube leaks not detected with bobbin probes
• Solution– CXB4 probe identified numerous defect morphologies
– Detected inlet end erosion, circumferential and axial cracking
CXB4 In Use
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Easy to Analyze
Axial Flaw
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Easy to Analyze
Circumferential Flaw
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Easy to Analyze
Volumetric Flaw
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Pitting
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Pitting Detection
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Two Pits in Close Proximity
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Pitting Detection
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Row of Pits
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Stress Corrosion Cracking
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Stress Corrosion Cracking Detection
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Circumferential Crack at an Expansion
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Pitting and Stress Corrosion Cracking
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Pitting and Stress Corrosion Cracking Detection
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Array Confirmation
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Array Call/Bobbin Miss
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Surface Solution – Surface Array Flex Probe
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• Use surface array probes to
– Augment or replace PT and MT
– Replace single coil ECT
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Surface Inspections
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Surface Array Flex Probe• Applications
– Surface and non-ferromagnetic sub-surface inspections
– Smooth weld inspection including crown, toe, and HAZ
– Successfully used in low pressure turbine rotor weld inspection
• Quick and Accurate– Inspection coverage up to 2 inches in a single pass
– Longitudinal, transverse, and oblique cracks as small as 0.020 in.
• Conforms to Various Surface Applications– Flexible pad wraps around weld beads up to 0.197 inches tall
– Detects corrosion under paint without stripping and repainting
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• An encoder can be attached to an ECA probe to enhance the quality of the inspection
– Provide distance measurements for signals of interest
– Control the sampling rate of the MIZ-200• Sample rate automatically adjusts based on encoder speed
• Consistent data density regardless of speed
– High encoding resolution aids flaw sizing
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Encoded Inspections
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Encircling Solution – RCCA
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• Designed for Taiwan Power (ISI solution)– Examine 24 rodlet clusters in 2 passes
– Encircling array probe to identify and characterize flaws
– RevospECT to provide fast and consistent results
• Processing power to perform auto-analysis
• Automatically analyzes the data quickly and accurately
• Consistent results using validated analysis techniques
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RCCA Inspection
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RCCA Inspection
MIZ-200 #1
MIZ-200 #2
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Eddy Current Engineered to Order (ETO)
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Eddy Current Engineered to Order (ETO)• Leverage Zetec patented array technology experience
• Solutions for a variety of inspection applications– Rod Cluster Control Assembly
– Fuel Rods
– Turbine Blades, Rotors, Blade Slots
– Carbon Steel Welds
– Complex Welds
– Tank Bottom Integrity
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Eddy Current Array Technology Provides
Fast, one-pass inspections Helps achieve outage excellence
Recordable replacement to PT and MT Helps achieve outage excellence
Complementary inspections to PAUT Helps achieve outage excellence
Enhanced defect detection and characterization Supports operational excellence
Leveraged technology for custom applications Enhances your cost management
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Thank You!
Learn more at: www.zetec.com/eddy-current-surface-array-solution/