Validation of simulation software for NDE applications in utility industry

Off-axis Detectionaxis of ultrasonic beam skewing performed using transverse waves at 45° steel via a plexiglass wedge GE SE1057... Experimental Procedure• Calibration for wedge delay, e

Validation of simulation software for NDE applications in utility industry

Thiago Seuaciuc-Osorio, George Connolly, Feng Yu and Mark Dennis

Electric Power Research Institute

The 5th International CANDU In-Service Inspection Workshop

in conjunction with the NDT in Canada 2014 Conference

June 16-18, 2014 Eaton Chelsea Hotel Toronto, ON (Canada)

• Background

• NDE Simulation Software: CIVA

• Validation of CIVA Simulation Results

• Summary

Our History…

• Founded by and for the electricity

i d t i 1973

• Independent, nonprofit center for

public interest energy and

public interest energy and

Charlotte and Lenox MA Chauncey StarrEPRI Founder

Charlotte and Lenox, MA EPRI Founder

Our Members…

• 450+ participants in more than 40

t i countries

• EPRI members generate more than 90% of the electricity in the

than 90% of the electricity in the United States

• International funding of more than International funding of more than 15% of EPRI’s research,

development and demonstrations

• Programs funded by more than 1,000 energy organizations

Challenges & Opportunities Associated with

NDE Modeling &Simulation

• Increasing scope of NDE

– Long Term Operation/License renewal

– Buried piping; Concrete, etc.

• Theoretical justification through modeling is considered

as a possible acceptable way of meeting the regulatory

requirements.

NDE simulation codes must be validated against experimental data to determine their suitability for

industrial application!

CIVA: Software Dedicated to NDE Simulation

– Developed by Commissariat à l’Energie Atomique (CEA), France

– Multiple techniques and modules

• UT : Ultrasound

• RT : X Rays

• ET : Eddy Currents

• Analysis tool (signal processing data reconstruction ) Analysis tool (signal processing, data reconstruction…)

– Generic Simulation Procedure of ET

Off-axis Detection

axis of ultrasonic beam (skewing)

performed using transverse waves at 45° (steel) via a plexiglass wedge

GE SE1057

Experimental Procedure

• Calibration for wedge delay, exit point from

wedge front and shear wave velocity

• Raster scanning is performed in 1mm steps g p p

in both scan (x) and index (y) directions

– Five different skew angles are used,

varying from 135° to 195°

– two cases are shown here: 150° and

index scan

– two cases are shown here: 150 and

195°

195° negative skew 150° positive skew

Comparison at 150° Positive Skew

• CIVA simulations are run in “Direct” mode; no reflections nor mode conversions are

4 5 6

4 5 6 7

EXP

CUMULATED SIDE VIEW

7

7 8

• Comparison is favorable; third through seventh SDHs detected experimentally

• Differences

– first two SDHs are not detected experimentally but are strongly present in the simulation CIVA predicting response along the length of the hole (was also the problem at the

– CIVA predicting response along the length of the hole (was also the problem at the

negative skew) instead of only at the corner

Comparison at 195° Negative Skew

• Cumulated side views:

195°

195°

4 5

3 2 1

5

6 7 8

• No SDH is detected experimentally; though there are blurred indications for upper SDHs

CUMULATED SIDE VIEW CUMULATED SIDE VIEW

• Simulated data show strong detection of every SDH

• Simulated results need further investigation to determine the reason for

these signals

Notched Block

TWT/TWE) in height from back surface

10 9 8 7 6SHALLOW NOTCHES

5 4 3 2 1

DEEP NOTCHES

Experimental and Simulated Results

• (top) cumulated VC top view, filtered

by time to remove backwall reflections

and (bottom) cumulated VC side view

• CIVA simulations performed using single contact element at 1.5 MHz

and (bottom) cumulated VC side view

• Responses from notches 1, 9 and 10

not discernible due to interference

– Simulated scan performed in 8 rows (15

mm apart); in each row, 456 data are collected (0.5 mm apart)

5 6

5 4 3

6 7 8

CUMULATED TOP VIEW

CUMULATED TOP VIEW

5 4 3 2 1

5 4 3 2 7

6

EXP

CUMULATED SIDE VIEW SIMCUMULATED SIDE VIEW

7 8

8

Comparison Summary

by (left) amplitude of response from second notch and (right)

amplitude of response from sixth notch

notches

6

2 3 4

5

SHALLOW NOTCHES DEEP NOTCHES

7

8

Comparison Summary

• Comparison of measured and actual depths of notches

– Both simulation and experiment tend to overestimate notch Both simulation and experiment tend to overestimate notch depth i.e., the notch TWT/TWE is slightly underestimated

– Error slightly worsens for shallowest notches

6

7

5

2 3 4 5 6

2 3

4

6 7

2

Austenitic Stainless Steel Piping Sample

• Piping sample from 10.0” NPS pipe

– contains two circumferential flaws contains two circumferential flaws

whose CL are at θ=30.0° and θ=78.1°

Experimental Procedure

• A circular 0.25” 3.5MHz conventional probe is used; scanning performed using transverse waves at 45° (steel) via a plexiglass wedge

– coupling between probe and wedge achieved by mineral oil p g p g y

– coupling between wedge and part achieved by running water

• Data collected by Zetec Omniscan MX 16-128

– controlling software: Zetec Ultravision 1.2R7

• ATCO LPS-1000 encoder used for motion control along two axes

Experimental and Simulated Results

filtered by time to remove

• CIVA simulations performed using single contact element at 3.5 MHz

– Simulated scan performed in 89 rows (0 8°

backwall reflections and (bottom)

cumulated VC end view

– Simulated scan performed in 89 rows (0.8 apart); in each row, 35 data are collected (1.0 mm apart)

CUMULATED TOP VIEW

UT Simulation Summary

cut into steel block

circumferential flaws in austenitic stainless steel piping sample

experiment given the main limitations:

no noise present in CIVA simulations

controlling number of modes and reflections

options are available to account for structural noise and other

simulation phenomena but computation time is greatly increased

experimental measurements for notched block and austenitic

experimental measurements for notched block and austenitic

stainless steel piping sample

Eddy Current Inspection of Steam Generator Tube w/ Holes

CIVA ET simulation

400 kHz bobbin coil, differential mode, ASME standard, IN 600, OD: 0.875” , WT: 0.05”

CIVA ET simulation vs experimental Results

400 kHz bobbin coil, differential mode, ASME standard, IN 600, OD: 0.875” , WT: 0.05”

Simulation results

Experimental results

CIVA ET Simulation vs Experimental Results

400 kHz bobbin coil, absolute mode, ASME standard, IN 600, OD: 0.875” , WT: 0.05”

Red: 100% thru; Black: 69%; Blue: 19%

CIVA RT Screen Dump

Tube Voltage: 220 kV; Tube Current 2 mA; focus-to-film distance : 25”: Exposure Time: 30 s

CIVA RT Simulation vs Experimental Results

Analytical, optical density (0-4) Analytical+ Monte-Carlo, optical density (0-4)

Bimetallic Welds Specimen

CIVA RT Simulation vs Experimental Results: Bimetallic Welds

Simulated Experimental

• General good qualitative agreement was achieved between experimental and CIVA results for the simulations performed in this study.

useful to interpret the underlying physics and signal observed in NDE

– useful to interpret the underlying physics and signal observed in NDE

measurements;

– provide a useful tool when training inspectors;

determine the influential parameters thru parametric studies

– determine the influential parameters thru parametric studies.

• Like any simulation tools for engineering applications, CIVA represents simplified and idealized NDE inspections

– critical to obtain the accurate information of the input parameters needed in CIVA simulation;

– Critical to validate CIVA models against experimental data for generic

inspection or on a case-by-case basis for complex inspections with respect to technique justification and demonstration for plant operation.

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