ULTRASONIC INSPECTION of DISSIMILAR WELDS Standard PWR Steam - - PowerPoint PPT Presentation

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ultrasonic inspection of dissimilar welds
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ULTRASONIC INSPECTION of DISSIMILAR WELDS Standard PWR Steam - - PowerPoint PPT Presentation

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ULTRASONIC LECTURES CONSULTING Michael Krning ULTRASONIC INSPECTION of DISSIMILAR WELDS Standard PWR Steam Generator Nozzle DMW Configuration (1) May 28 th , 2012 CITEC Su Zhou CONSULTING State-of-the-Art Ultrasonic Material Inspection

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SLIDE 1

CONSULTING

CITEC Su Zhou May 28th, 2012

ULTRASONIC LECTURES Michael Kröning

ULTRASONIC INSPECTION

  • f

DISSIMILAR WELDS

Standard PWR Steam Generator Nozzle DMW Configuration (1)

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SLIDE 2

CONSULTING

CITEC Su Zhou May 28th, 2012 Austenitic Weld Dissimilar Weld

State-of-the-Art Ultrasonic Material Inspection

Limitations

  • Anisotropic Material
  • Coarse Grain Material
  • Dispersive Material
  • Evaluation of Flaws
  • Scanning Surface

A Scan

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SLIDE 3

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION BY CAUSE Primary Water Stress Corrosion Cracking - PWSCC

Fracture Surface of Alloy 182 Weld Metal with Irregular Crack Front (2)

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SLIDE 4

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION BY CAUSE Primary Water Stress Corrosion Cracking - PWSCC

Cracking Susceptibility of various Alloys (3)

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SLIDE 5

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION BY CAUSE Primary Water Stress Corrosion Cracking - PWSCC

Component Item Date PWSCC Initially Observed Service Lifea (Calendar Years) Steam Generator Hot Leg Tubes and Plugs ~1973 ~2 Pressurizer Instrument Nozzles 1986 2 Steam Generator Cold Leg Tubes 1986 18 Pressurizer Heaters and Sleeves 1987 5 Steam Generator Channel Head Drain Pipes 1988 1 Control Rod Drive Mechanism Nozzles 1991 12 Hot Leg Instrument Nozzles 1991 5 Power Operated Relief Valve Safe End 1993 22 Pressurizer Nozzle Welds 1994 1 Cold Leg Piping Instrument Nozzles 1997 13 Reactor Vessel Hot Leg Nozzle Buttering/Piping Welds 2000 17 Control Rod Drive Mechanism Nozzle/RV Head Welds 2000 27 Surge Line Nozzle Welds 2002 21 Reactor Vessel Lower Head In-Core Instrumentation Nozzles/Welds 2003 14

Alloy 600 PWSCC Experience in Commercial PWRs Crack Initiation Times

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SLIDE 6

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION BY CAUSE Primary Water Stress Corrosion Cracking - PWSCC

PWSCC

WATER CHEMISTRY STRESS STATE MATERIAL STATE

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SLIDE 7

CONSULTING

CITEC Su Zhou May 28th, 2012

The generic IGSCC of the nickel-based Alloy 600 … in PWR has been studied extensively. Despite considerable experimental efforts, no consensus exists as to the nature of the cracking mechanism, and life modeling and remedial measures have had to rely on empirical, phenomenological correlations. By contrast, its counterpart in BWR, in terms of extent and cost of remedial measures, of IGSCC of sensitized, austenitic materials, benefits from a solid basis of fundamental understanding of the cracking mechanism for life modeling and repair remedies.

INSPECTION BY CAUSE Primary Water Stress Corrosion Cracking - PWSCC

2000 F.N. Speller Award Lecture by P.M. Scott, Framatome.

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SLIDE 8

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION BY CAUSE Primary Water Stress Corrosion Cracking - PWSCC

WATER CHEMISTRY

Main Parameters

  • hydrogen partial pressure

(or corrosion potential)

  • temperature

Mitigation Potential

  • zinc additions to

the reactor coolant system (Reduction of general corrosion)

  • temperature reduction

(thermally-activated mechanism )

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SLIDE 9

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION BY CAUSE Primary Water Stress Corrosion Cracking - PWSCC

Effect of zinc on corrosion rates of various alloys in laboratory tests (after Esposito et al.)

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SLIDE 10

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION BY CAUSE Primary Water Stress Corrosion Cracking - PWSCC

Example for the effect of zinc on time to initiate PWSCC in laboratory tests (after Esposito et al. 1991)

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SLIDE 11

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION BY CAUSE Primary Water Stress Corrosion Cracking - PWSCC

Degradation Factor as a Function of Temperature (ref. (David R. Forsyth, 2005))

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SLIDE 12

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION BY CAUSE Primary Water Stress Corrosion Cracking - PWSCC

STRESS STATE

Main Parameters

  • welding procedure
  • heat treatment

Mitigation Potential

  • Mechanical Surface

Enhancement (MSE)

  • stress relief heat treatment
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SLIDE 13

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION BY CAUSE Primary Water Stress Corrosion Cracking - PWSCC

Effects of heat treatment on SCC susceptibility

  • f Alloy 182

stress relief annealing

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SLIDE 14

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION BY CAUSE Primary Water Stress Corrosion Cracking - PWSCC

Mechanical Surface Enhancement (MSE):

shot peening flapper wheel grinding electrical-discharge machining electro-polishing abrasive water jet conditioning mechanical stress improvement process

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SLIDE 15

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION BY CAUSE Primary Water Stress Corrosion Cracking - PWSCC

MATERIAL STATE

Mitigation Potential

  • metals with 30% chromium

(threshold for PWSCC resistance: between 22 and 30% chromium)

  • quality assessment

(no repair, weld bead size, heat treatment, weld design)

Main Parameters

  • material and

weld microstructure

  • weld defects

(relatively large and sharp defects,

lack of fusion areas, promote PWSCC by acting as stress concentrators )

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SLIDE 16

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION BY CAUSE Primary Water Stress Corrosion Cracking - PWSCC

Assessment of Dissimilar Welds: “Risk for PWSCC”

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SLIDE 17

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION BY CAUSE Primary Water Stress Corrosion Cracking - PWSCC

The risk for PWSCC in alloy 600 components and its weld metal alloy 128/28 is low when best craftsmanship,

  • ptimized design, manufacturing and

fabrication can be certified by

  • documentation. Under these conditions,

both the stress resp. strain state and the material’s microstructure state of the critical component area are on a level to ascertain a low susceptibility to PWSCC.

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SLIDE 18

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION BY CAUSE Primary Water Stress Corrosion Cracking - PWSCC QUALITY ASSESSMENT FLAW DETECTION CRACK GROWTH RATES

NDT SUPPORTED MITIGATION CONCEPT

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SLIDE 19

CONSULTING

CITEC Su Zhou May 28th, 2012

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SLIDE 20

CONSULTING

CITEC Su Zhou May 28th, 2012

a b c

a - standard pipe to pipe weld b - narrow gap weld c - dissimilar weld

INSPECTION PROBLEM Acoustic Anisotropy

PHOTOMICROGRAPHS

  • f

WELD SECTIONS

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SLIDE 21

CONSULTING

CITEC Su Zhou May 28th, 2012

A-Scan Image

Impulse – Echo Technique

SIMULATION

akustisch isotrop

45° Shear Wave Transducer

INSPECTION PROBLEM Acoustic Anisotropy

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SLIDE 22

CONSULTING

CITEC Su Zhou May 28th, 2012

A-Scan Image

Impulse – Echo Technique

SIMULATION

transversal isotrop

45° Shear Wave Transducer

INSPECTION PROBLEM Acoustic Anisotropy

A-Scan Image

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SLIDE 23

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION PROBLEM Acoustic Anisotropy

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SLIDE 24

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION PROBLEM Acoustic Anisotropy

30 60 90 120 150 180 210 240 270 300 330 6000 4000 2000

Q

  • --- pressure wave
  • --- vertical shear wave
  • --- horizontal shear wave
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SLIDE 25

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION PROBLEM Acoustic Anisotropy

Model of the transverse isotropic structure of stainless steel weld joints Vph = Phase Velocity; Cij = Elastic Constant; ρ - Density, Φ – Fiber Orientation

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SLIDE 26

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION PROBLEM Acoustic Anisotropy

Rules for Practitioners SCATTERING:

  • LONGITUDINAL MODE

~ 8 times less than shear mode

  • FOCUSSING (T/R Transducers)

limits the contribution of scattering

  • FILTERING and BEAM FORMING

reduction of scattering contribution (TOPIC of R&D)

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SLIDE 27

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION PROBLEM Acoustic Anisotropy

False Call by Interface Reflection

  • S. PUDOVIKOV, A. BULAVINOV, R. PINCHUK, R. SRIDARAN VENKAT

Quantitative Ultraschallprüfungen an anisotropen Materialien mittels Sampling Phased Array Technik,

DGZfP-Jahrestagung 2010

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SLIDE 28

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION PROBLEM Acoustic Anisotropy

Rules for Practitioners BENDING:

  • LONGITUDINAL & SHEAR MODE
  • pposite behavior
  • FOCUSSING of LONG. MODE

at intersecting angles of 0° and 90°

  • DEFOCUSSING of LONG. MODE

at intersecting angles of +/- 45° TENDENCY of BENDING into the columnar grain orientation

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SLIDE 29

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION PROBLEM Acoustic Anisotropy

CARBON FIBER MODEL COMPOSITE

SOUND FIELD BENDING

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CONSULTING

CITEC Su Zhou May 28th, 2012

*Simulation by:

  • Dr. Schubert, Dr. Spies,

Fraunhofer IZFP

Modeling of sound propagation in transverse isotropic media*

0 dB

  • 24 dB

25 25

BENDING INTO THE FIBER/GRAIN ORIENTATION

INSPECTION PROBLEM Acoustic Anisotropy

CARBON FIBER MODEL COMPOSITE Φ = -45°

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SLIDE 31

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION PROBLEM Acoustic Anisotropy

FOKUSSING & DEFOKUSSING OF SOUND FIELDS IN TRANSVERSE ISOTRPIC MATERIALS

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SLIDE 32

CONSULTING

CITEC Su Zhou May 28th, 2012

R&D Reverse Phase Matching

Inspection of carbon-fiber structures

Angle beam (12°) insonification

  • f side drilled hole ∅ 3 mm

Sampling Phased array Conventional phased array

INSPECTION PROBLEM Acoustic Anisotropy

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SLIDE 33

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION PROBLEM Acoustic Anisotropy

Transverse and Longitudinal Sections with Homogeneous Anisotropic Structure

Structure of columnar grains

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SLIDE 34

CONSULTING

CITEC Su Zhou May 28th, 2012

Vertical weld, pipe horizontal Horizontal weld pipe vertical

Structure of columnar grains INSPECTION PROBLEM Acoustic Anisotropy

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SLIDE 35

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION PROBLEM Acoustic Anisotropy

TRANSVERSAL ISOTROPIC DOMAINS TID

DEFINITION: ACOUSTIC TRANSVERSAL ISOTROPIC DOMAINS TID SECTIONS WITH HOMOGENEOUS ACOUSTIC PROPERTIES

STRIP MODEL PIXEL/VOXEL MODEL

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SLIDE 36

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION PROBLEM Acoustic Anisotropy

a Test Specimen b Phased Array c Sampling Phased Array d Sampling Phased Array Phases Matched REFLECTOR POSITIONING BY MODEL SUPPORTED PHASE MATCHING

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SLIDE 37

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION PROBLEM Acoustic Anisotropy

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SLIDE 38

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION PROBLEM Geometry

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SLIDE 39

CONSULTING

CITEC Su Zhou May 28th, 2012

Case Studies: Surfaces

Simulation by Dr. Schubert

Fraunhofer IZFP-D

Transducer: normal probe f = 4 MHz Aperture: A = 10 mm Surface: flat

Snap Shot maximum intensity

INSPECTION PROBLEM Geometry

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SLIDE 40

CONSULTING

CITEC Su Zhou May 28th, 2012

Water gap depth (lense shaped): 0.74 mm (/2 in steel, 2 in water)

INSPECTION PROBLEM Geometry

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SLIDE 41

CONSULTING

CITEC Su Zhou May 28th, 2012

Water gap depth (lense shaped):

0.18 mm (/8 in steel, /2 in water)

INSPECTION PROBLEM Geometry

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SLIDE 42

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION PROBLEM Geometry

CONTOUR ANALYSIS

Surface Contour of Pipe to Elbow Weld

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SLIDE 43

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION PROBLEM Geometry

LOCALIZATION OF REFLECTOR INDICATIONS

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SLIDE 44

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION PROBLEM Geometry CONCLUSIONS Coupling; Bending; Attenuation; Shaped Inspection Geometry Affect with Systematic Errors:

REGISTRATION: AMPLITUDE CRITERIA IN REFERENCE TO CALIBRATION REFLECTORS EVALUATION: LOCALIZATION, CONTRAST & RESOLUTION SENSITIVITY

IMAGING OF SYSTEMATIC INDICATIONS

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SLIDE 45

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION PROBLEM Acoustic Anisotropy

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SLIDE 46

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION PROBLEM OPTIMIZATION SELECTION OF TRANSDUCERS

INSPECTION BY CAUSE DEFECT MODELING MICROSTRUCTURE SCATTERING REDUCTION ASSESSMENT OF TI DOMAINS SOUND PROPAGATION

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SLIDE 47

CONSULTING

CITEC Su Zhou May 28th, 2012

»Inspection by Highly Qualified Scientists«

= 45°

L Tv

= 60°

GW SN

Example of inspection planning

(1) Simulation of US wave propagation

List of Possible Transducers

  • 45°, 60°, 70° Shear Wave
  • 45°, 60°, 70° Longitudinal Wave
  • Double Element Transducers ADEPT
  • LLT Transducers
  • Mode Conversion Transducers
  • ‘Creeping wave’ Transducers

(3) Qualification of inspection technique & testing personnel

(2) Choice of appropriate transducers

INSPECTION PROBLEM OPTIMIZATION

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SLIDE 48

CONSULTING

CITEC Su Zhou May 28th, 2012

Most suitable

 = 45°

L Tv

 = 60°

75° L 60° L 45° T

Phased Array

45- 80° L 35- 80° T

REPLACEMENT OF TRANSDUCERS

INSPECTION PROBLEM OPTIMIZATION

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SLIDE 49

CONSULTING

CITEC Su Zhou May 28th, 2012

The ZETEC Advanced Phased Array Calculator is Useful for Generating Focal Laws (left) and Simulating the Sound Field for the Focal Law (right) to Determine Beam Characteristics

INSPECTION PROBLEM OPTIMIZATION

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SLIDE 50

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION PROBLEM RESEARCH & DEVELOPMENT

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SLIDE 51

CONSULTING

CITEC Su Zhou May 28th, 2012

The Principle of Inverse Phase Matching Calculation of time of flight in consideration of acoustic anisotropy Phase corrected summation

 

ij ij t

A   

RESEARCH & DEVELOPMENT REVERSE PHASE MATCHING

INSPECTION PROBLEM RESEARCH & DEVELOPMENT

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SLIDE 52

CONSULTING

CITEC Su Zhou May 28th, 2012

Phased array transducer and test specimen Conventional Phased Array

Backwall

Sampling Array with Reverse Phase Matching

Backwall Notch tip

Ultrasonics

C

INSPECTION PROBLEM RESEARCH & DEVELOPMENT

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CONSULTING

CITEC Su Zhou May 28th, 2012

B- Scan D- Scan C- Scan

8 mm 42 mm

US- Probe:

  • 16 Element SPA
  • Frequency 2 MHz

Technique:

  • 3D Sampling Phased Array

with SAFT Reconstruction

Inspection of austenitic narrow gap weld with root crack

INSPECTION PROBLEM RESEARCH & DEVELOPMENT

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SLIDE 54

CONSULTING

CITEC Su Zhou May 28th, 2012 8 mm 42 mm

Inspection of austenitic narrow gap weld with root crack 3D VISUALIZATION

INSPECTION PROBLEM RESEARCH & DEVELOPMENT

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SLIDE 55

CONSULTING

CITEC Su Zhou May 28th, 2012

INSPECTION PROBLEM RESEARCH & DEVELOPMENT

LET’S GO FOR INSPECTION