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Advanced Visual Testing TechnologiesAdvanced Visual Testing Technologies for In-Vessel Inspection
Y hi i S t h1) J S ki2) T O t b 2)Yoshinori Satoh1), Jun Suzuki2), Toru Ootsubo2)
1) Power and Industrial systems R&D Center,2) Isogo Nuclear Engineering Center,g g g ,
Power Systems Company, Toshiba Corporation
July 26, 2009
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BackgroundBackground
In-Vessel Visual Inspection (IVVI) as ISI based on the JSME S NA1–2004 :The following reactor internals is inspected b VT 3 for the standard inspectioninspected by VT-3 for the standard inspection;
Core Shroud;Jet pump;Shroud support;Top guide, Core plate and so on.
Individual Inspection for reactor internal is also needed;Individual Inspection for reactor internal is also needed;Inspection for stress corrosion cracking;Long interval compared to standard inspection (ex: 10years, 25years)EVT 1 should be used for the individual inspection;EVT-1 should be used for the individual inspection;
Enhancement of NDE technique is required;Advanced VT technique to achieve high accuracy; ECT or Laser-UT as alternative inspection for visual;High accuracy Ultrasonic testing (PA UT technique); and,Delivery and positioning technique.
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H4 Inside X-ShapeH7b Y-Shape
y p g q
Overview of TOSHIBA IVI TechnologiesOverview of TOSHIBA IVI TechnologiesIVI: In Vessel Inspection
Scan Device Inspection Technique
Phased Array UTISI Devices Equipment & Probe Family
B-Scan Image by 2D PAUT
3D Image by 3D PAUT
IVI: In-Vessel Inspection
In-vessel tools
High accuracy flaw depth sizing on weld surface by immersion
Probe Family
SCC
by 2D PAUT
SDH’s
by 3D PAUT
SCC
immersion technique.
Laser UT & ECT PT PT
Laser UT ECT
High resolved flaw detection and length & depth i i i th
ROV
SCC Specimen(1) SCC Specimen(2)
Advanced VTCrack
sizing in the reactor water.
Shroud
Super Resolution VT system3D VT system
SCC Specimen(3)
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Super Resolution Processing
Original
Phased Array UT
Ultrasonic beam is steered and f d b h t ll d
Beam Focusing Beam steering
ExcitingPulses
Elements
Beam Focusing Beam steering
ExcitingPulses
Elements
Beam Focusing Beam steering
ExcitingPulses
Elements
Principle
focused by phase controlled excitation of multiple array elements
FocalPoint
BeamDirection
WaveFront
FocalPoint
BeamDirection
WaveFront
FocalPoint
BeamDirection
WaveFront
Feature● Real time B-scan image carried out
FrontFrontFront
+ 45° 0°- 45°Water gap
Normal beam Angle beamExample of
array probes
gfor objective region
● Inspection condition can be changed according to defects and
+ 45 045
SC
C depth
(10mm
) + 4
5
Tip echo
changed according to defects and objective components
● Focused longitudinal wave is
-4
5°
0°
5°
SCCeffective for inspection of welds
● Immersion technique is notaffected to the surface condition
256chArray probe
Specimen(t=40mm)
SurfaceBackSurface
SCC
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affected to the surface condition p o eExample of B-scan image
Laser UT – PWR BMI
Work platforms
Optical fiber
Laser
Interferometer
Pulse
Laser
Principle
Cable tray
Insert tube(scanning
Transmission(Sizing)
SAW
CrackReflection(Detection)
Detection Laserm
(scanning mechanisms)
Optical fiber
R H E
18
Generation Laserand Laser Peening
R. H. E
Optical head
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and Laser Peening
Remotely Operated Vehicle (ROV) - Lineup
Shroud
Jet Pump
Shroud ROV
Shroud SupportShroud Support
ROV
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Shroud Support Small VehicleROV
ROV - FeaturesA li bl t i l i ti d l i ll- Applicable to in-vessel inspection and pool inner wall
inspection with highly accurate positioning capability.
Shroud ROV・ Accessible to 55 mm and more;
Small Vehicle・Approximately Dia. 140mm(Main body);
Shroud Support ROV・Drive below baffle plate・Demonstrated to EPRI;
・Demonstrated to EPRI;・Multi purpose use attaching various head (e g UT and B shing)
・Accessible to entire surface to be inspected;・Demonstrated to EPRI;
・Multi purpose use attaching various head (e.g. UT and Brushing).
(e.g. UT and Brushing). ・Manual operation; ・Stable by touching wheels on target.
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Operating Experience
Shroud VT 3 EVT 1 & UT Core Spray Piping / Sparger
・ VT-3, EVT-1 & UT(Phased array)
Core Spray Piping / Sparger・ EVT-1・ VT-3
J tJet pump・ VT-3, EVT-1Beam inspection: EVT-1, UTSet screw tack welds: EVT-1・ Set screw gap: VT-3・ Wedge & Rod wear: VT-3
Shroud support・VT-3
H7 H10: EVT 1 & UT
CRD housing & Stub tube・ VT 3 ・EVT 1
g・ H7, H10: EVT-1 & UT(Phased array)
・ H8, H9: EVT-1・ VT-3 ・EVT-1・ UT (Phased array)
BMI Nozzle (PWR)
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BWR Internals ・ UT (Laser UT)
Ad d VT T h l iAd d VT T h l iAdvanced VT TechnologiesAdvanced VT Technologies
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Requirement for VT technologies◆ Visual Testing (VT) for IVI
Detecting
In Vessel
gCracks
Inspector
Indirect visual Inspection
Adjusting camera manually while monitoring
・ VT is usually performed as “indirect” visual inspection using remote
cameras because target objects are under water and in high radiation area.
I t d t t k f f i t l t t th it
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・ Inspectors detect cracks on surface of internal structures on the monitor.
Requirement for VT technologies◆ Visual Testing (VT) for IVI
Detecting
In Vessel
gCracks
Inspector
Indirect visual Inspection
◆ Motivations
・Simplifying adjustment worksImageImage
Software
・Simplifying adjustment works
・Enhancing visibility on the monitor
・Providing intuitive visual interfaceOpticalOpticalDesignDesign
processingprocessing ・・SR VTSR VT・・3D VT3D VT
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Providing intuitive visual interface DesignDesignHardware
Super Resolution Technique
Raw data SR Image
◆ Example result of Super Resolution processing
SR processing
Spatial ResolutionSpatial Resolution
Super Resolution(SR)
Low Resolution (LR)
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(SR)(LR)
Overview of Super Resolution Technique◆ Principle of SR◆ Principle of SR
frame 1
Measuring relative position between frames in sub-pixel frame 2 paccuracy.
By superimposing the frames in sub pixel accuracy finer
Sub-pixel shift
in sub-pixel accuracy, finer grid (pixel) is composed.
Multiple frames(Temporal information)
Higher spatial resolution(Spatial information)
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(Temporal information) (Spatial information)
Overview of Super Resolution Technique
◆ Effects by applying Super Resolution (SR)
SR k hi h l ti i f l l ti id Thi• SR can make higher resolution images from a low resolution video. This behavior is equal to making camera close to objects.
→ SR can reduce difficult camera adjustment works jsuch as making cameras close to objects in narrow space. In other words, SR can reduce VT time.
• SR can be performed without expensive hardware but with software.
→ It can prevent from increasing in cost. It can prevent from increasing in cost.
• SR can enhance the resolution of VT video ONLY from frames in the id ith t dditi l i f tivideo without additional information.
→ SR has applicability to visual inspection activities.
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Overview of Super Resolution Technique◆ Algorithm construction for Super Resolution Imaging System◆ Algorithm construction for Super Resolution Imaging System
Raw video
①Measurement of relativeInterest FrameFrame 0
①Measurement of relative location in sub-pixel accuracy and evaluating i il it t i t t f
Frame 1similarity to interest frame.
②The intensity of HR image i ti t d f ti lA few
・
Frame 2is estimated from optimal frames statistically.
A few seconds
・・
Higher resolutionstill image
Frame Nstill image
N optimal frames One still image
①’ Optimal frames are
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frames One still imageregistered automatically.
Experimental Results◆ Experimental Configuration◆ Experimental Configuration
①Raw videoNTSC
Indirect
・CCD: 38Mpixel・Focus: f=25mm
Camerad ect
monitoring
Test PieceSR processingWD
Scan
X-Y stage②SR Image
SR: Super Resolution
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SR: Super ResolutionWD: Working Distance
Experimental Results◆ Case 1
SCC Test Piece Condition
◆ Case 1
Working Distance: 195mmField of View: 50mm×38mm
Condition
Field of View: 50mm×38mm
Resolution: 70μm/pixel
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SCC: Stress Corrosion Cracking
Experimental ResultsSR image
(Part of Test Piece)Raw Video
(Part of Test Piece)
Crack
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SR processing can enhance the crack in higher resolution
Experimental Results◆ Case 2
Cylindrical Test Piece Condition
◆ Case 2
Working Distance: 293mmField of View: 100mm×75mm
Resolution: 156μm/pixel
14mm
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Experimental ResultsRaw Video
(Part of Test Piece)SR image
(Part of Test Piece)
1 mil wire(0 0254mm)(0.0254mm)
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SR processing can enhance thin wire in higher resolution.
Experimental Results◆ Case 3
Cylindrical Test Piece Condition
◆ Case 3
Working Distance: 586 mmField of View: 150mm×113mm
Resolution: 234μm/pixel
14mm
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Experimental ResultsRaw Video
(Part of test piece)SR image
(Part of test piece)
1 mil wire(0.0254mm)( )
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SR processing can enhance thin wire in higher resolution.
Applicability Evaluation◆ Q antitati e E al ation of S per Resol tion (SR)◆ Quantitative Evaluation of Super Resolution (SR)
In order to evaluate applicability of SR “quantitatively”, we conducted visibility evaluation based on VT 1 grade of ASMEconducted visibility evaluation based on VT-1 grade of ASME.※ VT-1 must be demonstrated capable of resolving characters whose height is 1.1mm.
Raw frame SR image
Characters are unreadable because of low resolution
Characters become readable by use of SR
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Applicability Evaluation◆ Definition of Q antitati e Visibilit
For the evaluation, we compare the visibility of the characters S R l ti (SR) i t th t id
◆ Definition of Quantitative Visibility
on Super Resolution (SR) images to that on raw videos.
VisibilityVisibility
Readability: Ratio of the number of VT-1 characters which 3 yexaminers could read to the number of all test characters.
Readability (%) = (Number of characters which examiners could read)
/(N b f ll t t h t )×100(%)/(Number of all test characters)×100(%)
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Applicability Evaluation◆ Experimental Configuration◆ Experimental Configuration
①Raw video・CCD: 38Mpixel
NTSC
CameraIndirect
monitoring
p・Focus: f=8mm
SR processing(a) WD
(b) Scan
VT-1 charactersp g(a) WD
X-Y stage ②SR ImageSR: Super ResolutionWD: Working Distance X Y stage ②SR Image
(a) Comparing readabilities while changing working distance(b) Comparing readabilities while changing scanning speed
WD: Working Distance
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(b) Comparing readabilities while changing scanning speed
Applicability Evaluation◆ Comparison result while changing WD when scanning speed is 10mm/sec
100
◆ Comparison result while changing WD when scanning speed is 10mm/sec
75
%)
Visibility is enhanced
50
abili
ty (
%
2 R Vid (X1)
Rea
da
25 Raw Video (X1)One Frame (X1)SR Image (X3)
0
50 100 150 200SR S R l ti
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Working Distance (mm)SR: Super ResolutionWD: Working Distance
Applicability Evaluation◆ Comparison result while changing scanning speed when WD=200mm
100
Raw Video (X1)( )
◆ Comparison result while changing scanning speed when WD=200mm
75
One Frame (X1)SR Image (X3)
50bilit
y (%
)
25
Rea
dab
Vi ibilit i25 Visibility is enhanced
0
0 5 10 15 20 25S i S d ( / )SR S R l ti
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Scanning Speed (mm/sec)SR: Super ResolutionWD: Working Distance
Applicability Evaluation◆ Summary of evaluations
We can confirm that the use of the Super Resolution
It will be able to become easier and more flexibly to set
We can confirm that the use of the Super Resolution (SR) brings the following effects.
• It will be able to become easier and more flexibly to set the working distance of cameras in VT because SR can give nearer images with software.give nearer images with software.
• SR will be able to prevent camera motions from reducing visibility on monitor.g y
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3DVT Technique• 3-dimensional VT (3DVT) technique is based on Stereo
vision.
◆ Some information can be provided …(1) C k l th d t 3D th(1) Crack length and etc. on 3D path(2) 3D shapes (wire-frame, surface and texture model)(3) Cross-section view on reconstructed object surface(3) Cross-section view on reconstructed object surface
◆ Main Processes are◆ Main Processes are …(1) camera calibration (relative camera position and angle)angle)(2) image matching of 2 images from each camera(3) 3D-coordinates calculation using image pixel and
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camera parameters
Overview of 3DVT Technique• Configuration of this system with 3D camera head,
control device and processing device:
Power
Control Device
Power supply
Processing Device(PC)
3D Camera • 3D Camera head is consist of 2 camera and rotating table.
• Control Device is for signal communication and operation.
• Processing Device perform image processing calibration and
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Processing Device perform image processing, calibration and 3D-measurement process.
3D Camera for Flat Target3D Camera
Head3D Monitor Liq. Crystal
Glasses
EyesRight Side Image
Left Side Image
Eyes
Synchronous Signal Stereoscopic Effect
Left Side Image
Right Side Image
Effect
CCD
Prism
Liq. Crystal Shutter
Liq. Crystal Glasses
Mirror
Target
3D Camera Head
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3D Camera for Flat Target
◆ Configuration of 3D Camera Head
◆ Surface Shape Measurement Result
T t M i
■Field of View18mm x 14mm
Texture Mapping (Part of test piece)
■Depth-Resolution100μm
Right Side View Left Side View
Left Side Image(Part of test piece)
Right Side Image(Part of test piece) Wire Frame
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( p ) ( p ) Wire Frame(Part of test piece)
3D Camera for Pipe Target◆ M t t t◆ Measurement target(1) Welding part of CRD Housing and CRD stub tube (J-weld)(2) Welding part of CRD stub tube and RPV (3D-weld)( ) g p ( )
• In order to measure welding part of CRD stub tube …
◆ Restricted conditions
Vertical Scanning Part
(1) To mount on access device for being possible to scan and measure(2) To able to access and measure in a narrow space(3) To fix working distance (250mm in air)
CRD Housing
J elding part
Turn Scanning Part(Access Device)
Vertical Scanning Part(Access Device)
Turning and Scanning
(3) To fix working distance (250mm in air)
J welding part
CRD stub tube
3D welding part
Cramp Part for fixing device(Access Device)
M t H dJ welding part
Nuclear Reactor Pressure Vessel (RPV)
Measurement Headg
3D welding part
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(RPV)
3D Camera for Pipe Target◆ C fi ti f t t t h d
Camera: 640x480pixels, 1/4 inch (6.4mm) CCDHead Si e 50mm(L) 70mm(W) 30mm(D)
◆ Configuration of prototype measurement head
Head Size: 50mm(L)x70mm(W)x30mm(D)Measurement accuracy (depth): 0.5mm
Camera 1 Camera 2
Access Device
Light
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g
3D Camera for Pipe Target◆ Results of Mockup Experiment
Both welding parts (J-weld and 3D-weld) of the Mock-up were able to be measured surface shape of welding part.p g pWe can confirmed that our 3DVT technique and prototype measurement head were effective.
R d 3D h f R d 3D h f
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Reconstructed 3D shape of Mock-up J-weld
Reconstructed 3D shape of Mockup 3D-weld
Flexible 3D Camera System◆ Main functions◆ Main functions
Covering from micro measurement (crack length) to macro measurement (position, distance, level of internal structure) for Jet-p mppump
◆ Specifications(1) Measurement accuracy (depth): ( ) y ( p )
0.5mm (WD= 100mm), 5.0mm (WD = 600mm); (2) Field of view: 100x75mm or more
WD: Working Distance
Work positionFOV
Working distance
Cross point
θ
Work position
Camera 1
θ’
Stereo di it Camera 2
Optical axis
Rotating
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disparity Camera 2axisg
table
Prototype Head
Flexible 3D Camera System◆ R k bl i t◆ Remarkable points
(1) Working distance is variable change as rotating camera(2) Cross point of optical axis is adjusted most suitable angle automatically(3) Size measurement covering from tiny crack to large structure(4) Measuring distance on 3D path and direct distance between 2 ( ) g ppoints
Camera 1Camera 2
Rotate direction
Optical axisθ
Work position (short)
Working distance
θ
Work position (long)
Stereo disparity
Work position (short)
Field of view
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Cross point of optical axisWork position (long)
Flexible 3D Camera System◆ Example of 3D measurement (Main GUI)
Raw Image (Part of test piece)Raw Image (Part of test piece)
Setting 2 points (user action)
Reconstructed 3D shape(Part of test piece)
Path along surfaceCross-section
Linear path between 2 pointsDistance (linear)
( f )Distance (along surface)
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Flexible 3D Camera System◆ E l f 3D t i
A measurement result of a test piece which has welding part
(Working Distance: 350mm)
◆ Example of 3D measurement using zoom
(Working Distance: 350mm) Raw Image (Part of test piece)
Reconstructed 3D shape(Part of test piece)
Distance (linear)Distance (linear)
Distance (along surface)
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Flexible 3D Camera System◆ E l f 3D t i
A measurement result of a test piece which has welding part
(Working Distance: 350mm)
◆ Example of 3D measurement using zoom
(Working Distance: 350mm)
Raw Image (Part of test piece)
Reconstructed 3D shape(Part of test piece)
Distance (linear)Distance (linear)
Distance (along surface)
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Flexible 3D Camera System◆ A li bilit E l ti f Fl ibl 3D C
In order to verify applicability of this 3D VT system, we performed 3D measurement for the surface of Jet pump mock-up in full scale tank.
◆ Applicability Evaluation of Flexible 3D Camera
p p p
20m (Underwater)20m (Underwater)
Head Example image of the surface f J t k
Camera 1
Camera 2 J t P M k
25m (Underwater)
of Jet pump mock-up
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Camera 2 Jet Pump Mock-up
Flexible 3D Camera System◆ M t R lt f J t P M k
We can confirm that the profile (cross-section) data on the Jet Pump surface was obtained along cylindrical surface
◆ Measurement Result of Jet Pump Mock-up
surface was obtained along cylindrical surface. Camera 1
(Part of JP Mock-up)Camera 2
(Part of JP Mock-up) Profile on 3D surface(Part of JP Mock-up)
Distance (along surface)
Reconstructed 3D shape(Part of JP Mock-up)
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( )
Flexible 3D Camera System
Downsizing of proto-type 3D Camera head for narrow space
Camera 2 Rotating Table
Camera 1
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Flexible 3D Camera System• Developed the prototype measurement system by the
3DVT technique for shape reconstruction and crack length measurementlength measurement.
• Result of std. is less than 0.5mm (measurement resolution in design)resolution in design).Confirm to able to measure difference in level of 0.5mm.
• Conducted mock-up experiment for demonstrating the• Conducted mock-up experiment for demonstrating the effectiveness of 3DVT technique and the applicability of prototype measurement head of this system using p yp y gsimulated test piece of actual equipment shape.
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ConclusionConclusion
• Toshiba has various advanced NDE technologies, such as phased array UT and Laser-UT, and widely y yapplies these technologies to actual in-vessel inspections for nuclear power plants.
• In particular, distinctive VT technologies have been developed;
- Super resolution (SR) VT enables to produce a still i h i 3 ti b tt l ti f i i limage having 3 times better resolution from original low-resolution video data.
3 di i l (3D) VT bl t tit ti l- 3-dimensional (3D) VT enables to quantitatively reconstruct object shapes with an accuracy of 0.5mm.
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