ML071350646
| ML071350646 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 05/08/2007 |
| From: | Broussard J, Collin J, White G Dominion Engineering |
| To: | Office of Nuclear Reactor Regulation |
| Mensah T | |
| References | |
| Download: ML071350646 (132) | |
Text
11730 Plaza America Dr. #310 Reston, VA 20190 703.437.1155 www.domeng.com Advanced FEA Crack Growth Calculations for Evaluation of PWR Pressurizer Nozzle Dissimilar Metal Weld Circumferential PWSCC Sponsored by: EPRI Materials Reliability Program Presented To:
Expert Review Panel for Advanced FEA Crack Growth Calculations Presented By:
Glenn White John Broussard Jean Collin Dominion Engineering, Inc.
Tuesday, May 8, 2007 Status Meeting on Implications of Wolf Creek Dissimilar Metal Weld Inspections Bethesda North Marriott Hotel and Conference Center North Bethesda, Maryland
Project Review Meeting: Advanced FEA Crack Growth Evaluations 2
May 8, 2007, North Bethesda, Maryland Topics
Introductions - Industry and NRC
Status of Industry work, including response to April 4, 2007 NRC letter - Industry
Status of NRC Confirmatory Research - NRC
Presentation & Discussion of Proposed Matrix - Industry
Additional topics - Industry and NRC Critical Crack Size Calculations (if not covered in bullet 2) - Industry Validation studies and WRS mockups - Industry Benchmarking NRC/Industry K Solutions for the Advanced FEA Calculations -
Industry and NRC Leak-rate Calculations - Industry
Plans for next meeting(s) - Industry and NRC
Meeting Summary and Conclusions - Industry and NRC
Project Review Meeting: Advanced FEA Crack Growth Evaluations 3
May 8, 2007, North Bethesda, Maryland Principal Meeting Participants EPRI Project Management / Support
- Craig Harrington, EPRI
- Tim Gilman, Structural Integrity Associates Project Team
- Glenn White, DEI
- John Broussard, DEI
- Jean Collin, DEI
- Greg Thorwald, Quest Reliability, LLC Expert Review Panel
- Ted Anderson, Quest Reliability, LLC
- Warren Bamford, Westinghouse
- Doug Killian, AREVA
- Pete Riccardella, Structural Integrity Associates
- Ken Yoon, AREVA NRC Participants
- Al Csontos, NRC Research
- Bob Hardies, NRC Research
- Dave Rudland, EMC2
- Simon Sheng, NRC NRR
- Ted Sullivan, NRC NRR
Project Review Meeting: Advanced FEA Crack Growth Evaluations 4
May 8, 2007, North Bethesda, Maryland Project Plan Phase II Calculations Perform detailed sensitivity studies, benchmarking, and validation work specific to the pressurizer nozzle DM welds in the 9 spring 2008 plants to evaluate the viability of leak before break for these welds
- Collection of geometry, loading, and weld repair data for 9 spring 2008 plants
- Background on fracture mechanics basis for stress intensity factor calculation
- Further software verification activities
- Treatment of welding residual stress
- Critical crack size calculation basis
- Setting and evaluation of matrix of sensitivity cases using cylindrical shell geometry
- Evaluation of effect of multiple flaws
- Model validation efforts
- Participation of industry and NRC experts to build consensus
- Probabilistic calculation to investigate likelihood that the Wolf Creek indications were really growing as rapidly as assumed in the White Paper and NRC calculations
- Final report with methodology, results, and validation in EPRI format
Project Review Meeting: Advanced FEA Crack Growth Evaluations 5
May 8, 2007, North Bethesda, Maryland Project Plan Additional Calculations with Crack Inserted into WRS Model Perform selected sensitivity cases with crack mesh inserted directly into three-dimensional welding residual stress FEA model:
- More precise calculation of stresses for nozzle-to-safe-end geometry
- Direct input of welding residual stresses from welding residual stress FEA model, rather than user selection of welding residual stress cases
- Consideration of secondary effects such as local thermal stresses due to difference in coefficient of thermal expansion for each material
- Because this modeling is more labor-and CPU-intensive compared to modeling using cylindrical shell geometry and residual stresses simulated via temperature field input, this model will be used to evaluate a subset of the full matrix of cases
- The cylindrical shell model also has the advantage of allowing direct comparison with published stress intensity factor solutions, including those considering the standard ASME welding residual stress assumptions
Project Review Meeting: Advanced FEA Crack Growth Evaluations 6
May 8, 2007, North Bethesda, Maryland Work Status Summary Assessment of plant-specific inputs for 51 welds in 9 spring 2008 plants
- Dimensions
- Piping loads
- Available weld repair information Critical crack size calculations
- Limit load calculations for through-wall flaws in 51 welds
- Limit load calculations for part-depth flaws in 51 welds
- Limit load calculations for custom crack profile (part-depth and through-wall)
- Assessment of EPFM failure mode Crack growth calculations for custom crack shape
- FEACrack software extensions
- Modeling refinements
- Effect of moment magnitude and initial crack assumption
- Stability of calculated crack progression
- Element and time step size refinement studies
- Use of WRC Bulletin 471 axisymmetric solution as scoping tool
Project Review Meeting: Advanced FEA Crack Growth Evaluations 7
May 8, 2007, North Bethesda, Maryland Work Status Summary (contd)
Leak rate calculations
- PICEP and SQUIRT models
- Calculation of COD and leak rate using PICEP as scoping tool
- Calculation of leak rate with COD from complex crack growth FEA calculations Development of matrix of WRS profiles
- Axisymmetric (self balance at every circumferential position)
- Non-axisymmetric (self balance over entire cross section)
Development of analysis case matrix Software verification and benchmarking Validation planning
Project Review Meeting: Advanced FEA Crack Growth Evaluations 8
May 8, 2007, North Bethesda, Maryland Work Status Software Development The status of the new FEACrack software modules by Quest Reliability, LLC is as follows:
- Growth of surface crack with custom profile (including with nodal repositioning routine): Issued
- Apply user-defined temperature distribution for the cylinder model with a text box "macro" input: Issued
- Implement rigid surface contact for crack face closure in the quarter symmetric cylinder: Issued
- Add custom 360° surface circ crack to mesh generator with custom crack growth in the fatigue growth module: Issued
- Implement fatigue crack growth for custom crack front profile for through-wall crack
(<360° on ID & 360° on ID): In progress
- New nozzle-to-safe-end geometry to facilitate placing crack into FEA WRS model:
May timeframe See presentation by Greg Thorwald of Quest Reliability, LLC for discussion of FEACrack software extensions
New and Future Features in FEACrack Greg Thorwald, Ph.D.
303-415-1475
Outline - FEACrack Features Recently Developed
Custom surface crack
Ansys macro text, input temperature gradient
Custom 360o crack
Node redistribution, fatigue analysis Future Development
Complex custom crack
Update custom through-wall crack
Nozzle to safe end geometry
Custom Surface Crack
Enter all crack front node coordinates
Any number of nodes, arbitrary spacing
All nodes updated during fatigue analysis
Custom 360o Crack
Enter all crack front node coordinates
- Any number of nodes, arbitrary spacing
- All nodes updated during fatigue analysis
Node Redistribution
An option for fatigue analysis
- helps avoid numerical problems at the crack tip
Nodes shift downward along the crack front
Relocate nodes on updated crack front to preserve the relative node spacing
Complex Custom Crack
Through-wall crack shape at the OD crack tip
Crack front curves to a part-depth crack along pipe ID
Use custom crack coordinates for all crack front nodes
Quarter symmetric model
Custom Through-Wall Crack Thumbnail Profile Slanted Profile
Custom through-wall crack is available
Test and update for custom crack fatigue analysis
- Update all crack front nodes during fatigue
- Slanted profile to continue fatigue analysis from surface crack results
New Nozzle Geometry Source: MRP 2007-003 Attachment 1 (White Paper).
Nozzle-to-safe-end geometry
Add to FEACrack geometry library
Automatically create the crack mesh in the nozzle geometry
Allow automated parametric analysis
Project Review Meeting: Advanced FEA Crack Growth Evaluations 9
May 8, 2007, North Bethesda, Maryland April 4, 2007, NRC Letter Comments on Crack Growth Calculation Comment #1. The industry incremented the crack growth in the analyses based on constant increment of crack growth in the length direction for the majority of the analyses.
This constraint caused the times for the crack extension at the surface and depth to be different. Even though these differences are small, over the entire time period the sum of the differences could be substantial. This difference could bring into question the validity of the crack shape at leakage. Growing the crack along the crack front by a constant time increment seems more logical and more representative of the crack growth physical characteristics. We suggest further investigation into the crack increment calculation is warranted.
Response. As discussed with the NRC on the April 9 conference call, this comment represents a misunderstanding of the crack increment calculation method. A standard fully explicit time stepping procedure is applied. In order to investigate the adequacy of the time step size in the Phase I calculation, an improved estimate of the elapsed time was calculated based on the crack growth rates from the stress intensity factor at the beginning and at the end of each time step. In the most recent industry work, we are explicitly decreasing the time step size to confirm time and crack profile convergence.
Project Review Meeting: Advanced FEA Crack Growth Evaluations 10 May 8, 2007, North Bethesda, Maryland April 4, 2007, NRC Letter Comments on Crack Growth Calculation Comment #2. In Figure 11 of industrys Phase I calculations on the evolution of the stress intensity factors, a discontinuity occurred after the second increment of crack growth, and appears to occur at the same stress intensity for each of the remaining steps. Industrys response to a question on this observation during the March 20, 2007, teleconference was unclear, but industry indicated they believed the response was real. We suggest further investigation into the mesh density or the crack increment calculation is warranted. It is recognized that this effect is probably secondary in nature.
Response. The observed behavior is a real effect in terms of the stress intensity factor being locally high where the crack front profile is not smooth. In recent work, DEI has concluded that this behavior observed in the draft Phase I calculation was an artifact of the crack growth increment size. Reducing the crack increment along the ID circumference results in a fully behaved stress intensity factor profile. The new results for the Phase I calculation inputs confirm that this issue in fact had a small effect on the crack profile at the point of through-wall penetration.
Project Review Meeting: Advanced FEA Crack Growth Evaluations 11 May 8, 2007, North Bethesda, Maryland Refined Phase I Calc Results Figure 1: FEA FM Model Using FEACrack / ANSYS 1.0" 8.0" Symmetry Boundary Conditions Pressure Applied to Crack Face Axial Force and Effective Total Moment Temperature profile applied to red region to produce WRS profile
Project Review Meeting: Advanced FEA Crack Growth Evaluations 12 May 8, 2007, North Bethesda, Maryland Refined Phase I Calc Results Methodology Adjustments Mesh refinement changes to shift additional nodes at surface region of crack front Temperature loading adjustments and mesh refinement changes to improve through-wall stress distribution Crack shape study to develop more natural crack shape for initial size parameters Reduced crack growth / time increment
- 3X previous number of steps
- Maintains flaw shape stability during automatic crack growth
- Use new arbitrary depth ID circ flaw capability when flaw reaches 360°
- Ligament between crack ends conservatively eliminated instantaneously as partial-arc crack approaches 360°
Project Review Meeting: Advanced FEA Crack Growth Evaluations 13 May 8, 2007, North Bethesda, Maryland Refined Phase I Calc Results Figure 2: WRS Distribution Assumption Based on ASME Data
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10 20 30 40 50 60 70 0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Normalized Distance from ID Surface, (r-ri)/t Axial Welding Residual Stress (ksi)
Desired Crack Depth 180 Side Temperature profile improved to match desired curve PRELIMINARY
Project Review Meeting: Advanced FEA Crack Growth Evaluations 14 May 8, 2007, North Bethesda, Maryland Refined Phase I Calc Results Figure 3: Assumed Axial Stress Loading for Crack Growth Identical load case assumed as previous
- Endcap pressure load
- Dead weight force and moment
- Pipe thermal expansion force and moment
- Assumed WRS distribution Crack face pressure also applied
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-10 0
10 20 30 40 50 60 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 Normalized Distance from ID Surface, (r-ri)/t Axial Stress with Residual Stress (ksi) 0° 22.5° 45° 67.5° 90° 112.5° 135° 157.5° 180°
= 0° to 180°
= 0° is circumferential position of maximum bending axial stress;
= 90° is bending neutral axis
Project Review Meeting: Advanced FEA Crack Growth Evaluations 15 May 8, 2007, North Bethesda, Maryland Refined Phase I Calc Results Figure 4: Axial Extent of Imposed Thermal Stress Simulating WRS
-10,000 0
10,000 20,000 30,000 40,000 50,000 60,000 70,000 0.00 0.50 1.00 1.50 2.00 2.50 3.00 Axial Distance (in)
Axial Stress (psi)
Original Model Crack Side Stress Distribution Opposite Crack Side Stress Distribution PRELIMINARY
Project Review Meeting: Advanced FEA Crack Growth Evaluations 16 May 8, 2007, North Bethesda, Maryland 0
0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0
0.5 1
1.5 2
2.5 3
3.5 4
Circumferential Distance Along ID (in)
Crack Depth (in)
Initial Flaw for "Grown" Case "Grown" Flaw Shape Pure Semi-Ellipse Flaw Shape Refined Phase I Calc Results Methodology Adjustments Natural shape developed by growing semi-ellipse shape out to desired depth and length PRELIMINARY
Project Review Meeting: Advanced FEA Crack Growth Evaluations 17 May 8, 2007, North Bethesda, Maryland 0
5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Relative Distance Along Crack Front from Deepest Point to Surface Point (--)
FEA Stress Intensity Factor, K (psi-in0.5)
Initial Flaw for "Grown" Case "Grown" Flaw Shape Pure Semi-Ellipse Flaw Shape Refined Phase I Calc Results Methodology Adjustments (contd)
Additional refinement and natural shape yield smoother crack tip SIF profile PRELIMINARY
Project Review Meeting: Advanced FEA Crack Growth Evaluations 18 May 8, 2007, North Bethesda, Maryland Refined Phase I Calc Results Figure 7: Growth Progression in Flat Plane 0.00 0.20 0.40 0.60 0.80 1.00 1.20 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 Circumferential Distance Along ID (in)
Crack Depth (in) 2c/a=20.9, a/t=0.260 2c/a=18.9, a/t=0.310 2c/a=18.4, a/t=0.342 2c/a=18.5, a/t=0.375 2c/a=19.0, a/t=0.395 2c/a=19.5, a/t=0.413 2c/a=20.0, a/t=0.428 2c/a=20.5, a/t=0.439 2c/a=21.3, a/t=0.454 2c/a=21.9, a/t=0.466 2c/a=22.6, a/t=0.481 2c/a=23.1, a/t=0.493 2c/a=ID circ, a/t=0.493 2c/a=ID circ, a/t=0.548 2c/a=ID circ, a/t=0.626 2c/a=ID circ, a/t=0.703 2c/a=ID circ, a/t=0.781 2c/a=ID circ, a/t=0.858 2c/a=ID circ, a/t=0.936 2c/a=ID circ, a/t=1.000 Selected growth steps shown PRELIMINARY
Project Review Meeting: Advanced FEA Crack Growth Evaluations 19 May 8, 2007, North Bethesda, Maryland Refined Phase I Calc Results Profile Comparison vs. Draft Phase 1 Result PRELIMINARY 0.00 0.20 0.40 0.60 0.80 1.00 1.20 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 Circumferential Distance Along ID (in)
Crack Depth (in)
Original Model Final Shape Current Model Final Shape
Project Review Meeting: Advanced FEA Crack Growth Evaluations 20 May 8, 2007, North Bethesda, Maryland 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0
1 2
3 4
5 6
7 8
time (yr) a/t - Full Moment a/t - Half Moment Fraction Cracked - Full Moment Refined Phase I Calc Results Figure 9: Crack Depth and Area Development PRELIMINARY
Project Review Meeting: Advanced FEA Crack Growth Evaluations 21 May 8, 2007, North Bethesda, Maryland 0
5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Relative Distance Along Crack Front from Deepest Point to Surface Point (--)
FEA Stress Intensity Factor, K (psi-in0.5) 2c/a=20.9, a/t=0.260 2c/a=18.9, a/t=0.310 2c/a=18.4, a/t=0.342 2c/a=18.5, a/t=0.375 2c/a=19.0, a/t=0.395 2c/a=19.5, a/t=0.413 2c/a=20.0, a/t=0.428 2c/a=20.5, a/t=0.439 2c/a=21.3, a/t=0.454 2c/a=21.9, a/t=0.466 2c/a=22.6, a/t=0.481 2c/a=23.1, a/t=0.493 2c/a=ID circ, a/t=0.493 2c/a=ID circ, a/t=0.548 2c/a=ID circ, a/t=0.626 2c/a=ID circ, a/t=0.703 2c/a=ID circ, a/t=0.781 2c/a=ID circ, a/t=0.858 2c/a=ID circ, a/t=0.936 Refined Phase I Calc Results Figure 11: SIF Along Crack Front PRELIMINARY Selected growth steps shown
Project Review Meeting: Advanced FEA Crack Growth Evaluations 22 May 8, 2007, North Bethesda, Maryland Refined Phase I Calc Results Figure 12: SIF at Deepest and Surface Points vs. Depth 0
5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Maximum Crack Depth, a/t Crack-Tip Stress Intensity Factor, K (psi-in0.5)
K at Deepest Point K at Surface Point K at Joined Edge PRELIMINARY
Project Review Meeting: Advanced FEA Crack Growth Evaluations 23 May 8, 2007, North Bethesda, Maryland Refined Phase I Calc Results Figure 14: Crack Stability - Supportable Moment 0
500 1,000 1,500 2,000 2,500 3,000 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 a/t Max Supportable Moment (in-kips)
Entire Crack in Tension Crack Takes Compression Crack Does Not Take Compression Applied Moment PRELIMINARY Supportable moment based on standard thin-wall NSC model for arbitrary circumferential crack profile (Rahman and Wilkowski, 1998)
Project Review Meeting: Advanced FEA Crack Growth Evaluations 24 May 8, 2007, North Bethesda, Maryland Refined Phase I Calc Results Summary Through-wall flaw reached after approximately 7.5 years
- Increase in growth time due to refined time step and other refinements Net section collapse moment for final flaw shape is 1300 in-kips vs. 275 in-kips load (4.7x greater)
- Based on conservative case in which crack face does not take compression
Project Review Meeting: Advanced FEA Crack Growth Evaluations 25 May 8, 2007, North Bethesda, Maryland April 4, 2007, NRC Letter Comments on Crack Growth Calculation Comment #3. A significant result from these analyses was that the surface crack grew to 360 degrees before becoming through-wall. This effect was driven by the higher residual stresses at the inside diameter (ID) surface. In addition, the shape of the final defect at the location of maximum stress was highly driven by the magnitude of the bending stress relative to the ID welding residual stress. For similar residual stresses with lower bending moments, a critical 360-degree surface crack is likely to occur. Industry needs to address this issue in the analysis matrix for Phase II.
Response. As discussed in the draft Phase I calculation note, the growth to a 360° degree surface flaw results from the somewhat higher stress intensity factors along the surface associated with the crack shape in the ID surface neighborhood, compared to the results for a semi-elliptical flaw shape assumption. As has been discussed since the beginning of the project, the magnitude of the bending stress is expected to be a critical modeling parameter. Phase II was planned to include investigation of the effect of bending moment load based on the full range of piping moment loads collected for the group of 51 subject welds. Contrary to the statement regarding the likelihood of critical 360° surface cracks, recent work indicates that the surface crack is likely to arrest or greatly slow in growth without reaching critical crack size given lower bending moments and similar residual stresses (see following slides).
Project Review Meeting: Advanced FEA Crack Growth Evaluations 26 May 8, 2007, North Bethesda, Maryland Crack Growth with Zero Moment Axisymmetric Results for WC Relief Nozzle with 360° Flaw Assumed axisymmetric stress profile at right Endcap pressure based on ID at DM weld Dead weight axial force included Normal thermal axial force included WRS profile of Phase 1 calculation also assumed
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10 20 30 40 50 60 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 Normalized Distance from ID Surface, x/t Axial Stress with Residual Stress (ksi)
EndCap Press + DW + T + WRS PRELIMINARY
Project Review Meeting: Advanced FEA Crack Growth Evaluations 27 May 8, 2007, North Bethesda, Maryland Crack Growth with Zero Moment Axisymmetric Results for WC Relief Nozzle with 360° Flaw SIF per WRC Bulletin solution for fully axisymmetric stress field (cubic dependence on radial coordinate) and 360° uniform depth circumferential surface crack WRC Bulletin includes influence coefficients for case of Ri/t = 2, so no extrapolation needed Crack face pressure applied via superposition
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10 20 30 40 50 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 Normalized Crack Depth, a/t Stress Intensity Factor with Residual Stress (ksi-in0.5)
EndCap Press + CrackFaceP + DW + T + WRS PRELIMINARY
Project Review Meeting: Advanced FEA Crack Growth Evaluations 28 May 8, 2007, North Bethesda, Maryland Crack Growth with Zero Moment Axisymmetric Results for WC Relief Nozzle with 360° Flaw Crack depth vs. time based on integration of MRP-115 CGR equation at 650°F Crack arrest predicted at depth of about a/t = 0.35 Conclusion is that without piping moment load, assumed WRS profile results in arrested (and stable) part-depth crack for the relief nozzle case investigated, regardless of initial crack aspect ratio 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0
2 4
6 8
10 12 14 16 18 20 Time (years)
Normalized Crack Depth from ID Surface, a/t EndCap Press + CrackFaceP + DW + T + WRS PRELIMINARY
Project Review Meeting: Advanced FEA Crack Growth Evaluations 29 May 8, 2007, North Bethesda, Maryland Crack Growth with Axisymmetric Moment Axisymmetric Results for WC Relief Nozzle with 360° Flaw Assumed axisymmetric stress profile at right Axisymmetric linear stress profile Mr/I added to previous zero moment case M taken as half base case moment of 275 in-kips This hypothetical axisymmetric case bounds capability of moment to drive crack through-wall for assumed WRS profile
-30
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10 20 30 40 50 60 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 Normalized Distance from ID Surface, x/t Axial Stress with Residual Stress (ksi)
EndCap Press + DW + T + WRS PRELIMINARY
Project Review Meeting: Advanced FEA Crack Growth Evaluations 30 May 8, 2007, North Bethesda, Maryland Crack Growth with Axisymmetric Moment Axisymmetric Results for WC Relief Nozzle with 360° Flaw Same SIF solution procedure as before using WRC Bulletin Crack face pressure applied via superposition
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10 20 30 40 50 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 Normalized Crack Depth, a/t Stress Intensity Factor with Residual Stress (ksi-in0.5)
EndCap Press + CrackFaceP + DW + T + WRS PRELIMINARY
Project Review Meeting: Advanced FEA Crack Growth Evaluations 31 May 8, 2007, North Bethesda, Maryland Crack Growth with Axisymmetric Moment Axisymmetric Results for WC Relief Nozzle with 360° Flaw Crack depth vs. time based on integration of MRP-115 CGR equation at 650°F Crack arrest predicted at depth of about a/t = 0.45 Conclusion is that even with half base case moment of 275 in-kips, assumed WRS profile results in arrested (and stable) part-depth crack for the relief nozzle case investigated, regardless of initial crack aspect ratio 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0
10 20 30 40 50 60 Time (years)
Normalized Crack Depth from ID Surface, a/t EndCap Press + CrackFaceP + DW + T + WRS PRELIMINARY
Project Review Meeting: Advanced FEA Crack Growth Evaluations 32 May 8, 2007, North Bethesda, Maryland 0.00 0.20 0.40 0.60 0.80 1.00 1.20 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 Circumferential Distance Along ID (in)
Crack Depth (in) 2c/a=20.9, a/t=0.260 2c/a=19.8, a/t=0.303 2c/a=20.0, a/t=0.326 2c/a=20.7, a/t=0.342 2c/a=21.5, a/t=0.354 2c/a=22.5, a/t=0.363 2c/a=23.5, a/t=0.370 2c/a=24.6, a/t=0.376 2c/a=25.7, a/t=0.381 2c/a=26.8, a/t=0.385 2c/a=27.9, a/t=0.389 2c/a=29.1, a/t=0.392 2c/a=ID circ, a/t=0.392 2c/a=ID circ, a/t=0.399 2c/a=ID circ, a/t=0.426 Crack Growth with Reduced Moment FEA Results for WC Relief Nozzle with 21:1 Flaw Growth progression in flat plane for case of half previously assumed piping moment PRELIMINARY Selected growth steps shown
Project Review Meeting: Advanced FEA Crack Growth Evaluations 33 May 8, 2007, North Bethesda, Maryland Crack Growth with Reduced Moment FEA Results for WC Relief Nozzle with 21:1 Flaw 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0
1 2
3 4
5 6
7 8
time (yr) a/t Full Moment Half Moment PRELIMINARY Crack depth development for case of half previously assumed piping moment
Project Review Meeting: Advanced FEA Crack Growth Evaluations 34 May 8, 2007, North Bethesda, Maryland Crack Growth with Reduced Moment FEA Results for WC Relief Nozzle with 21:1 Flaw SIF along crack front for case of half previously assumed piping moment 0
5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Relative Distance Along Crack Front from Surface Point to Deepest Point (--)
FEA Stress Intensity Factor, K (psi-in0.5) 2c/a=20.9, a/t=0.260 2c/a=19.8, a/t=0.303 2c/a=20.0, a/t=0.326 2c/a=20.7, a/t=0.342 2c/a=21.5, a/t=0.354 2c/a=22.5, a/t=0.363 2c/a=23.5, a/t=0.370 2c/a=24.6, a/t=0.376 2c/a=25.7, a/t=0.381 2c/a=26.8, a/t=0.385 2c/a=27.9, a/t=0.389 2c/a=29.1, a/t=0.392 2c/a=ID circ, a/t=0.392 2c/a=ID circ, a/t=0.399 2c/a=ID circ, a/t=0.426 PRELIMINARY Selected growth steps shown
Project Review Meeting: Advanced FEA Crack Growth Evaluations 35 May 8, 2007, North Bethesda, Maryland 0
5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Maximum Crack Depth, a/t Crack-Tip Stress Intensity Factor, K (psi-in0.5)
K at Deepest Point K at Surface Point K at Joined Edge Crack Growth with Reduced Moment FEA Results for WC Relief Nozzle with 21:1 Flaw SIF at deepest and surface points vs. depth for case of half previously assumed piping moment PRELIMINARY
Project Review Meeting: Advanced FEA Crack Growth Evaluations 36 May 8, 2007, North Bethesda, Maryland Crack Growth with Full Moment FEA Results for WC Relief Nozzle with 360° Flaw Initial and final flaw shape comparison for partial-arc initial flaw vs. 360° initial flaw 0.00 0.20 0.40 0.60 0.80 1.00 1.20 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 Circumferential Distance Along ID (in)
Crack Depth (in)
Start w/ PD 26% deep @ 21:1 Start w/ ID 360 @ 10% deep PD Initial Flaw Shape ID Circ Initial Flaw Shape PRELIMINARY
Project Review Meeting: Advanced FEA Crack Growth Evaluations 37 May 8, 2007, North Bethesda, Maryland New FEA Crack Growth Cases Conclusions Smooth crack-tip SIF profiles result from greater mesh refinement at surface and smaller time step increment
- Starting from natural flaw shape does not improve SIF profiles Greater time step refinement (with other minor changes) yields time to through-wall of about 7.5 years Reduced moment leads to flaw arrest for assumed through-wall stress distribution High inside surface stresses lead to no significant difference in crack profile at through-wall penetration for partial-arc and 360° circumferential starting flaws
- 360° initial flaw @ 10% depth takes 8.4 years to reach same final flaw shape
Project Review Meeting: Advanced FEA Crack Growth Evaluations 38 May 8, 2007, North Bethesda, Maryland April 4, 2007, NRC Letter Comments on Critical Crack Size Calculation
Comment #4. The last comment relates to the calculation of critical crack sizes which affect the calculation for the time to rupture. In the Phase I results, industry used a limit-load analysis with the weld metal flow stress to estimate the critical through-wall crack size; then industry used that cross-sectional cracked area to draw conclusions about the stability of the leaking surface crack.
In addition, industry did not evaluate the displacement-controlled stresses in this stability calculation, arguing that these stresses would be relieved by the plasticity and change in compliance due to the large crack. From reviewing past full-scale pipe testing results, it is the NRC staffs view that in conducting critical crack size analyses, industry must address the following concerns.
- Comment #4a. The location of the crack in a dissimilar weld can change the fracture response. If the crack is close to the safe-end then the lower strength of the stainless steel safe-end should be used. If the crack is in the center of the weld or closer to the ferritic nozzle side, the effective flow stress would be slightly higher than using the safe-end strength but much lower than using the weld metal strength properties. Hence, if the location of the crack in the weld is not known, then the conservative assumption is to use the lower safe-end strength properties. This fact is supported by both analyses and experiments.
Project Review Meeting: Advanced FEA Crack Growth Evaluations 39 May 8, 2007, North Bethesda, Maryland April 4, 2007, NRC Letter Comments on Critical Crack Size Calculation (contd)
- Comment #4b. Elastic-plastic fracture mechanics should be considered since in the NRC analyses, this condition controlled for some crack geometries. For an idealized circumferential through-wall crack as used in industrys failure analysis, the NRC staffs detailed finite element elastic-plastic analyses and pipe tests showed that failure stress would be below that predicted by limit-load analyses even when using the stainless-steel base-metal strength properties in the limit load analysis. For a circumferential surface flaw, the experiments and analyses suggest that limit-load using the lower strength properties would be appropriate. Finally, for a complex or compound crack, i.e., a long surface crack that penetrates the wall thickness for a short length, full-scale pipe tests have shown that the failure stress would be significantly below limit load. This crack shape is similar to the flaw found in the Duane Arnold safe end. The results also indicate that secondary stresses can lead to rapid severance of pipes containing complex cracks. Consequently, there can be significant non-conservatism in the industrys fracture analysis.
Project Review Meeting: Advanced FEA Crack Growth Evaluations 40 May 8, 2007, North Bethesda, Maryland April 4, 2007, NRC Letter Comments on Critical Crack Size Calculation (contd)
- Comment #4c. For large cracks, especially surface and complex cracks, the plasticity is localized to the area surrounding the crack, and therefore the secondary loads will not be relieved by a change in compliance. If the crack is large enough so that the rest of the pipe system remains elastic, then these secondary stresses will act as a primary stress. If the failure stresses are above yield of the uncracked pipe, there will be a gradual reduction of the importance of secondary stresses, but this is material and pipe-system geometry dependant.
This condition may begin to relieve some of these loads, but total relief will not occur until there is large scale plasticity in the uncracked pipe loop. This secondary stress effect on fracture response is consistent with the ASME Section III design rules that offer a warning about Local Overstrain due to a weakened pipe cross section. There are full-scale pipe system tests with different amounts of thermal expansion stress that illustrate this fracture behavior in NUREG reports and technical papers.
Project Review Meeting: Advanced FEA Crack Growth Evaluations 41 May 8, 2007, North Bethesda, Maryland April 4, 2007, NRC Letter Industry Response to Comment #4 Pete Riccardella of SI to present main response to Comment #4 Additional response material on next two slides
- Ductile tearing of thin surface ligaments
- Nominal stress in adjacent piping
Project Review Meeting: Advanced FEA Crack Growth Evaluations 42 May 8, 2007, North Bethesda, Maryland April 4, 2007, NRC Letter Ductile Tearing of Thin Surface Ligaments Section 2.2.1 and Figure 4 of the draft EMC2 technical basis document for critical crack size recommend that a factor be applied for deep surface cracks There is an important distinction between a leakage failure (rupture of local ligament between crack tip and OD) and a break failure. All surface cracks will be predicted to have a leakage "failure" as they approach 100% through-wall according to the correction factor approach in Figure 4 of the EMC2 document.
If the through-wall crack created is stable, then in fact leakage and not a LOCA will result. We must check for thin surface ligaments at the ends of the through-wall section of the final complex crack.
A second order question is whether any surface ligament tearing during the previous crack growth changes the crack growth pattern significantly versus growth by SCC only. Under the conditions that could produce local ligament ductile tearing, the predicted SCC growth rate will be high, effectively simulating the effect of the surface ligament tearing.
R. Kurihara, S. Ueda, and D. Sturm, Estimation of the Ductile Unstable Fracture of Pipe with a Circumferential Surface Crack Subjected to Bending, Nuclear Engineering and Design, Vol. 106, pp. 265-273, 1988.
Project Review Meeting: Advanced FEA Crack Growth Evaluations 43 May 8, 2007, North Bethesda, Maryland April 4, 2007, NRC Letter Nominal Stress in Adjacent Piping This plots shows nominal stress in the attached piping assuming the same pressure, axial force, and effective moment Meff as reported for the nozzles The stress is shown relative to the Code yield strength based on preliminary piping material assumptions These results show yield level stresses in some safety/relief and spray nozzle cases all surge nozzle cases The results may be relevant regarding the role of secondary stress in the crack stability calculations 0.0 0.5 1.0 1.5 2.0 2.5 01 A - Re (7.75x5.17) 02 A - SA (7.75x5.17) 03 A - SB (7.75x5.17) 04 A - SC (7.75x5.17) 05 E - Re (7.75x5.17) 06 E - SA (7.75x5.17) 07 E - SB (7.75x5.17) 08 E - SC (7.75x5.17) 09 H - Re (7.75x5.17) 10 H - SA (7.75x5.17) 11 H - SB (7.75x5.17) 12 H - SC (7.75x5.17)
WC1 J - Re (7.75x5.17)
WC1a J - Re/Sa (7.75x5.17)
WC2 J - SA (7.75x5.17)
WC3 J - SB (7.75x5.17)
WC4 J - SC (7.75x5.17) 13 F - Re (8x5.19) 14 F - SA (8x5.19) 15 F - SB (8x5.19) 16 F - SC (8x5.19) 17 B - Re (7.75x5.62) 18 B - SA (7.75x5.62) 19 B - SB (7.75x5.62) 20 B - SC (7.75x5.62) 21 G - Re (7.75x5.62) 22 G - SA (7.75x5.62) 23 G - SB (7.75x5.62) 24 G - SC (7.75x5.62) 25 C - Re (7.75x5.62) 26 C - SA (7.75x5.62) 27 C - SB (7.75x5.62) 28 C - SC (7.75x5.62) 29 D - Re (8x4.937) 30 D - SA (8x4.937) 31 D - SB (8x4.937) 32 D - SC (8x4.937) 33 I - Re (8x4.937) 34 I - SA (8x4.937) 35 I - SB (8x4.937) 36 A - Sp (5.81x4.01) 37 E - Sp (5.81x4.01)
WC5 J - Sp (5.81x4.01) 38 B - Sp (5.81x4.25) 39 G - Sp (5.81x4.25) 40 C - Sp (5.81x4.25) 41 F - Sp (8x5.695) 42 D - Sp (5.188x3.062) 43 I - Sp (5.188x3.25) 44 A - Su (15x11.844) 45 E - Su (15x11.844) 46 H - Su (15x11.844)
WC6 J - Su (15x11.844) 47 B - Su (15x11.844) 48 G - Su (15x11.844) 49 C - Su (15x11.875) 50 D - Su (13.063x10.125) 51 I - Su (13.063x10.125)
(Pm +Pb )/y 0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0.00 0.75 1.50 2.25 3.00 3.75 4.50 5.25 6.00 6.75 7.50 8.25 9.00 9.75 10.50 11.25 12.00 12.75 13.50 14.25 15.00 15.75 16.50 17.25 18.00 18.75 19.50 20.25 21.00 21.75 22.50 23.25 24.00 24.75 25.50 26.25 27.00 27.75 28.50 29.25 30.00 30.75 31.50 32.25 33.00 33.75 34.50 35.25 36.00 36.75 37.50 38.25 39.00 39.75 40.50 41.25 42.00 42.75 43.50 44.25 45.00 45.75 46.50 47.25 48.00 48.75 49.50 50.25 51.00 51.75 52.50 53.25 54.00 54.75 55.50 56.25 57.00 57.75 58.50 59.25 60.00 P+DW+T P+DW+T+Tstrat Notes
- 1. Pm = PDo/4t + Faxial/Ametal where Faxial = DW+T or DW+T+Tstrat axial force and Ametal = (Do 2 - Di 2)/4
- 2. Pb = MeffDo/2I where I = (Ro 4 - Ri 4)/4
- 3. y = 18.5 ksi for S&R and spray piping based on Code min YS for A376 TP316 at 650°F
- 4. y = 18.0 ksi for surge line piping based on Code min YS for A376 TP304 at 650°F
Project Review Meeting: Advanced FEA Crack Growth Evaluations 44 May 8, 2007, North Bethesda, Maryland Status of NRC Confirmatory Research
To be presented by NRC
Project Review Meeting: Advanced FEA Crack Growth Evaluations 45 May 8, 2007, North Bethesda, Maryland Proposed Case Matrix Items
Item 1. Plant Specific Geometries
Item 2. Plant Specific Loads
Item 3. Proposed Weld Residual Stresses Cracks growing in an axisymmetric WRS field Cracks growing in an axisymmetric + repair WRS field
Item 4. Crack Growth Rate Equation
Item 5. Multiple Crack Growth Calculations
Other Items Initial flaw geometry Redistribution of load given high WRS at ID surface Crack inserted directly into the 3-dimensional DEI WRS FEA model
Project Review Meeting: Advanced FEA Crack Growth Evaluations 46 May 8, 2007, North Bethesda, Maryland Nozzle Geometry for Subject Plants Summary There are a total of 51 pressurizer DM welds of concern in the group of nine plants:
- 35 safety and relief (S&R) nozzles (1 plant has only three S&R nozzles)
- 8 surge nozzles (+1 already overlayed)
- 8 spray nozzles (+1 examined by PDI process in 2005)
Using design drawings, basic weld dimensions have been tabulated for the 51 subject welds:
- Weld thickness For welds with taper from LAS nozzle to safe end, thickness is based on average of design diameters at toe on nozzle and at toe on safe end Liner or sleeve thickness not included in weld thickness for cases in which liner or sleeve is in direct contact with DM weld
- Radius to thickness ratio (Ri/t) based on design inside diameter at weld and weld thickness per previous bullet
- Approximate weld separation axial distance between root of DM weld and root of SS weld to piping
Project Review Meeting: Advanced FEA Crack Growth Evaluations 47 May 8, 2007, North Bethesda, Maryland Nozzle Geometry for Subject Plants Geometry Cases A review of design drawings for the nine plants indicates the following nozzle geometry cases:
- S&R nozzles Types 1a and 1b: W design without liner, connected to 6 pipe Types 2a and 2b: W design with liner directly covering DM weld, connected to 6 pipe Type 3: CE design (no liner), connected to 6 pipe
- Spray nozzles Type 4: W design with liner (does not extend to most of DM weld), connected to 4 pipe Type 5: W design with liner directly covering DM weld, connected to 4 pipe Type 6: W design without liner, connected to 6 pipe Type 7: CE design (no liner, sleeve not extending to DM weld), connected to 4 pipe
- Surge nozzles Type 8: W design (sleeve directly covers fill-in weld under nozzle-to-safe-end weld),
connected to 14 pipe Type 9: CE design (sleeve not extending to DM weld), connected to 12 pipe
Project Review Meeting: Advanced FEA Crack Growth Evaluations 48 May 8, 2007, North Bethesda, Maryland Nozzle Geometry and Repair History PRELIMINARY Summary Table Design #
Piping NPS Liner?
DM Weld t (in.)
(in.)
Butter Weld Repairs ID Weld Repairs OD Weld Repairs Design #
Piping NPS Liner?
DM Weld t (in.)
(in.)
Butter Weld Repairs ID Weld Repairs OD Weld Repairs Plant A 1a 6"
N 1.29 2.0 2.2 NR NR NR 1a 6"
N 1.29 2.0 2.2 NR NR R4 Plant E 1a 6"
N 1.29 2.0 2.2 NR NR R
1a 6"
N 1.29 2.0 2.2 NR NR NR Plant H 1a 6"
N 1.29 2.0 2.2 NR NR NR 1a 6"
N 1.29 2.0 2.2 NR R
R Plant B 2a 6"
Y 1.07 2.6 2.6 NR NR R1 2a 6"
Y 1.07 2.6 2.6 NR NR NR Plant G 2a 6"
Y 1.07 2.6 2.6 NR NR NR 2a 6"
Y 1.07 2.6 2.6 NR NR NR Plant C 2b 6"
Y 1.07 2.6 2.3 NR NR NR 2b 6"
Y 1.07 2.6 2.3 Plant F 1b 6"
N 1.41 1.8 3.3 NR NR NR 1b 6"
N 1.41 1.8 3.3 Plant D 3
6" N
1.41 1.8 6.8 NR NR NR 3
6" N
1.41 1.8 6.8 R
NR NR Plant I 3
6" N
1.41 1.8 6.8 N/A N/A N/A 3
6" N
1.41 1.8 6.8 N/A N/A N/A Plant J 1a 6"
N 1.29 2.0 2.2 Rx5 R1 R1 1a 6"
N 1.29 2.0 2.2 R
R2 NR Notes:
- 1. For Designs #2a, #2b, and #5, liner directly covers DM weld.
- 2. For Design #4, liner does not extend to most of DM weld.
- 6. NR = No weld repairs reported
- 7. Rn = Repairs reported (n indicates number of defect or repaired areas if reported; "x" indicates repeat weld repair operations)
- 8. N/A = Results for fabrication records review not available
- 9. Weld repair entries for Plants C and F are preliminary.
- 10. All pressurizer nozzle DM welds in Plant H are reported to be Alloy 82, not Alloy 82/182.
Safety A Plant Code Relief R
R
Project Review Meeting: Advanced FEA Crack Growth Evaluations 49 May 8, 2007, North Bethesda, Maryland Nozzle Geometry and Repair History PRELIMINARY Summary Table (contd)
Design #
Piping NPS Liner?
DM Weld t (in.)
(in.)
Butter Weld Repairs ID Weld Repairs OD Weld Repairs Design #
Piping NPS Liner?
DM Weld t (in.)
(in.)
Butter Weld Repairs ID Weld Repairs OD Weld Repairs Plant A 1a 6"
N 1.29 2.0 2.2 NR R1 NR 1a 6"
N 1.29 2.0 2.2 NR NR NR Plant E 1a 6"
N 1.29 2.0 2.2 NR NR NR 1a 6"
N 1.29 2.0 2.2 NR R
NR Plant H 1a 6"
N 1.29 2.0 2.2 NR NR NR 1a 6"
N 1.29 2.0 2.2 NR NR NR Plant B 2a 6"
Y 1.07 2.6 2.6 NR NR NR 2a 6"
Y 1.07 2.6 2.6 NR NR NR Plant G 2a 6"
Y 1.07 2.6 2.6 NR NR NR 2a 6"
Y 1.07 2.6 2.6 NR NR NR Plant C 2b 6"
Y 1.07 2.6 2.3 2b 6"
Y 1.07 2.6 2.3 Plant F 1b 6"
N 1.41 1.8 3.3 NR NR NR 1b 6"
N 1.41 1.8 3.3 NR NR NR Plant D 3
6" N
1.41 1.8 6.8 NR NR NR 3
6" N
1.41 1.8 6.8 NR NR NR Plant I 3
6" N
1.41 1.8 6.8 N/A N/A N/A Plant J 1a 6"
N 1.29 2.0 2.2 NR R6x2 NR 1a 6"
N 1.29 2.0 2.2 NR NR NR Notes:
- 1. For Designs #2a, #2b, and #5, liner directly covers DM weld.
- 2. For Design #4, liner does not extend to most of DM weld.
- 6. NR = No weld repairs reported
- 7. Rn = Repairs reported (n indicates number of defect or repaired areas if reported; "x" indicates repeat weld repair operations)
- 8. N/A = Results for fabrication records review not available
- 9. Weld repair entries for Plants C and F are preliminary.
- 10. All pressurizer nozzle DM welds in Plant H are reported to be Alloy 82, not Alloy 82/182.
Plant Code Safety B Safety C No Safety C R
R
Project Review Meeting: Advanced FEA Crack Growth Evaluations 50 May 8, 2007, North Bethesda, Maryland Nozzle Geometry and Repair History PRELIMINARY Summary Table (contd)
Design #
Piping NPS Liner?
DM Weld t (in.)
(in.)
Butter Weld Repairs ID Weld Repairs OD Weld Repairs Design #
Piping NPS Liner?
DM Weld t (in.)
(in.)
Butter Weld Repairs ID Weld Repairs OD Weld Repairs Plant A 4
4" Y
0.90 2.2
~2.3 NR NR NR 8
14" N
1.58 3.8 3.4 NR R5 R3 Plant E 4
4" Y
0.90 2.2
~2.3 R
NR R
8 14" N
1.58 3.8 3.4 NR R3 NR Plant H 8
14" N
1.58 3.8 3.4 NR NR NR Plant B 5
4" Y
0.78 2.7 2.2 NR NR NR 8
14" N
1.58 3.8 3.4 R1 R1x2 R2 Plant G 5
4" Y
0.78 2.7 2.2 NR NR NR 8
14" N
1.58 3.8 3.4 NR NR NR Plant C 5
4" Y
0.78 2.7
~2.2 8
14" N
1.56 3.8 3.5 NR NR NR Plant F 6
6" N
1.15 2.5 3.6 NR NR NR Plant D 7
4" N
1.06 1.4 3.3 NR NR NR 9
12" N
1.47 3.4 3.0 NR NR NR Plant I 7
4" N
1.06 1.4 3.3 N/A N/A N/A 9
12" N
1.47 3.4 3.0 N/A N/A N/A Plant J 4
4" Y
0.90 2.2
~2.3 R
NR NR 8
14" N
1.58 3.8 3.4 R2 R1 NR Notes:
- 1. For Designs #2a, #2b, and #5, liner directly covers DM weld.
- 2. For Design #4, liner does not extend to most of DM weld.
- 6. NR = No weld repairs reported
- 7. Rn = Repairs reported (n indicates number of defect or repaired areas if reported; "x" indicates repeat weld repair operations)
- 8. N/A = Results for fabrication records review not available
- 9. Weld repair entries for Plants C and F are preliminary.
- 10. All pressurizer nozzle DM welds in Plant H are reported to be Alloy 82, not Alloy 82/182.
Plant Code Spray (all have thermal sleeve)
Surge (all have thermal sleeve)
Already PDI examined Already structural overlayed R
Project Review Meeting: Advanced FEA Crack Growth Evaluations 51 May 8, 2007, North Bethesda, Maryland Nozzle Geometry for Subject Plants Basic Weld Dimensions 0
2 4
6 8
10 12 14 01 A - Re (7.75x5.17) 02 A - SA (7.75x5.17) 03 A - SB (7.75x5.17) 04 A - SC (7.75x5.17) 05 E - Re (7.75x5.17) 06 E - SA (7.75x5.17) 07 E - SB (7.75x5.17) 08 E - SC (7.75x5.17) 09 H - Re (7.75x5.17) 10 H - SA (7.75x5.17) 11 H - SB (7.75x5.17) 12 H - SC (7.75x5.17)
WC1 J - Re (7.75x5.17)
WC1a J - Re/Sa (7.75x5.17)
WC2 J - SA (7.75x5.17)
WC3 J - SB (7.75x5.17)
WC4 J - SC (7.75x5.17) 13 F - Re (8x5.19) 14 F - SA (8x5.19) 15 F - SB (8x5.19) 16 F - SC (8x5.19) 17 B - Re (7.75x5.62) 18 B - SA (7.75x5.62) 19 B - SB (7.75x5.62) 20 B - SC (7.75x5.62) 21 G - Re (7.75x5.62) 22 G - SA (7.75x5.62) 23 G - SB (7.75x5.62) 24 G - SC (7.75x5.62) 25 C - Re (7.75x5.62) 26 C - SA (7.75x5.62) 27 C - SB (7.75x5.62) 28 C - SC (7.75x5.62) 29 D - Re (8x5.19) 30 D - SA (8x5.19) 31 D - SB (8x5.19) 32 D - SC (8x5.19) 33 I - Re (8x5.188) 34 I - SA (8x5.188) 35 I - SB (8x5.188) 36 A - Sp (5.81x4.01) 37 E - Sp (5.81x4.01)
WC5 J - Sp (5.81x4.01) 38 B - Sp (5.81x4.25) 39 G - Sp (5.81x4.25) 40 C - Sp (5.81x4.25) 41 F - Sp (8x5.695) 42 D - Sp (5.188x3.062) 43 I - Sp (5.188x3.25) 44 A - Su (15x11.844) 45 E - Su (15x11.844) 46 H - Su (15x11.844)
WC6 J - Su (15x11.844) 47 B - Su (15x11.844) 48 G - Su (15x11.844) 49 C - Su (15x11.875) 50 D - Su (13.063x10.125) 51 I - Su (13.063x10.125) 0 50 100 150 200 250 300 350 400 0.00 0.75 1.50 2.25 3.00 3.75 4.50 5.25 6.00 6.75 7.50 8.25 9.00 9.75 10.50 11.25 12.00 12.75 13.50 14.25 15.00 15.75 16.50 17.25 18.00 18.75 19.50 20.25 21.00 21.75 22.50 23.25 24.00 24.75 25.50 26.25 27.00 27.75 28.50 29.25 30.00 30.75 31.50 32.25 33.00 33.75 34.50 35.25 36.00 36.75 37.50 38.25 39.00 39.75 40.50 41.25 42.00 42.75 43.50 44.25 45.00 45.75 46.50 47.25 48.00 48.75 49.50 50.25 51.00 51.75 52.50 53.25 54.00 54.75 55.50 56.25 57.00 57.75 58.50 59.25 60.00 ID (in)
OD (in) t (in)
ID/t
Project Review Meeting: Advanced FEA Crack Growth Evaluations 52 May 8, 2007, North Bethesda, Maryland Nozzle Geometry for Subject Plants As-Built Dimensional Information Available as-built dimensions are being collected for the subject welds This information is being used to investigate as-built versus design dimensions:
- DM weld OD (average between toe on nozzle and toe on safe end)
- DM weld thickness
- Separation distance between DM and SS welds Sensitivity cases for the crack growth and crack stability calculations are planned to check sensitivity to as-built dimensions
Project Review Meeting: Advanced FEA Crack Growth Evaluations 53 May 8, 2007, North Bethesda, Maryland As-Built Dimensional Information Review of Plant H As-Built Dimensions Following as-built dimensions are preliminary Safety/Relief
- LAS nozzle end thickness of 1.16 - 1.37 vs. design of 1.42 (including cladding)
- Butter thickness of 0.80 vs. design of 0.81 Spray
- LAS nozzle end thickness of 0.87 - 0.92 vs. design of 1.00 (including liner) and 0.88 (without liner)
- Safe end OD at DM weld of ~5.65 vs. design of 5.62 Surge
- LAS nozzle end thickness of 1.40 - 1.60 vs. design of 1.51 (including cladding)
- Butter thickness of 0.30 vs. design of 0.81 In general, as-built thickness of butter buildup on LAS nozzle end can vary significantly
Project Review Meeting: Advanced FEA Crack Growth Evaluations 54 May 8, 2007, North Bethesda, Maryland As-Built Dimensional Information Review of Plant C As-Built Dimensions Following as-built dimensions are preliminary
- There is uncertainty in the weld separation figures because only axial length of various materials on OD is provided Relief
- Separation distance of ~2.18 vs. design of 2.32
- DM weld circumference of 24.5 vs. design of 24.3 (based on average OD of 7.75)
- DM weld thickness of 1.14 vs. design of 1.07 (without liner)
Safety A
- Separation distance of ~2.2 vs. design of 2.32 Safety B
- Separation distance of ~1.85 vs. design of 2.32
- DM weld thickness of 1.08 vs. design of 1.07 (without liner)
Safety C
- Separation distance of ~2.3 vs. design of 2.32
- DM weld thickness of 1.14 vs. design of 1.07 (without liner)
Project Review Meeting: Advanced FEA Crack Growth Evaluations 55 May 8, 2007, North Bethesda, Maryland As-Built Dimensional Information Review of Plant C As-Built Dimensions (contd)
Spray
- Separation distance of ~3.25 vs. design of 2.2 Surge
- Separation distance of ~3.73 vs. design of 3.46
- Average DM weld thickness of 1.501 vs. design of 1.563
- DM weld circumference of 46.875 vs. design of 47.12 (based on OD of 15.00)
Project Review Meeting: Advanced FEA Crack Growth Evaluations 56 May 8, 2007, North Bethesda, Maryland Plant-Specific Piping Loads Approach Design pipe loads have now been collected for each of the 51 subject welds Differences in pipe axial force and moment loads have multiple effects on the relative crack growth rate in the radial and circumferential directions, as well as an effect on critical crack size Therefore, cover full range of piping loads for 51 subject welds:
- All plants 2235 psig pressure
- Range of axial membrane stress loading, Pm
- Range of bending stress loading, Pb
- Range of ratio of bending to total stress loading, Pb/(Pm+Pb)
- Crack growth loads include dead weight and normal thermal pipe expansion loads (and normal thermal stratification loads in case of surge nozzles)
- Length of thermal strain applied to simulate WRS will be varied
Project Review Meeting: Advanced FEA Crack Growth Evaluations 57 May 8, 2007, North Bethesda, Maryland Plant-Specific Piping Loads Nominal Axial Piping Loads (Not Including Endcap Pressure Load) 0 10 20 30 40 01 A - Re (7.75x5.17) 02 A - SA (7.75x5.17) 03 A - SB (7.75x5.17) 04 A - SC (7.75x5.17) 05 E - Re (7.75x5.17) 06 E - SA (7.75x5.17) 07 E - SB (7.75x5.17) 08 E - SC (7.75x5.17) 09 H - Re (7.75x5.17) 10 H - SA (7.75x5.17) 11 H - SB (7.75x5.17) 12 H - SC (7.75x5.17)
WC1 J - Re (7.75x5.17)
WC1a J - Re/Sa (7.75x5.17)
WC2 J - SA (7.75x5.17)
WC3 J - SB (7.75x5.17)
WC4 J - SC (7.75x5.17) 13 F - Re (8x5.19) 14 F - SA (8x5.19) 15 F - SB (8x5.19) 16 F - SC (8x5.19) 17 B - Re (7.75x5.62) 18 B - SA (7.75x5.62) 19 B - SB (7.75x5.62) 20 B - SC (7.75x5.62) 21 G - Re (7.75x5.62) 22 G - SA (7.75x5.62) 23 G - SB (7.75x5.62) 24 G - SC (7.75x5.62) 25 C - Re (7.75x5.62) 26 C - SA (7.75x5.62) 27 C - SB (7.75x5.62) 28 C - SC (7.75x5.62) 29 D - Re (8x5.19) 30 D - SA (8x5.19) 31 D - SB (8x5.19) 32 D - SC (8x5.19) 33 I - Re (8x5.188) 34 I - SA (8x5.188) 35 I - SB (8x5.188) 36 A - Sp (5.81x4.01) 37 E - Sp (5.81x4.01)
WC5 J - Sp (5.81x4.01) 38 B - Sp (5.81x4.25) 39 G - Sp (5.81x4.25) 40 C - Sp (5.81x4.25) 41 F - Sp (8x5.695) 42 D - Sp (5.188x3.062) 43 I - Sp (5.188x3.25) 44 A - Su (15x11.844) 45 E - Su (15x11.844) 46 H - Su (15x11.844)
WC6 J - Su (15x11.844) 47 B - Su (15x11.844) 48 G - Su (15x11.844) 49 C - Su (15x11.875) 50 D - Su (13.063x10.125) 51 I - Su (13.063x10.125)
Faxial (kips) 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0.00 0.75 1.50 2.25 3.00 3.75 4.50 5.25 6.00 6.75 7.50 8.25 9.00 9.75 10.50 11.25 12.00 12.75 13.50 14.25 15.00 15.75 16.50 17.25 18.00 18.75 19.50 20.25 21.00 21.75 22.50 23.25 24.00 24.75 25.50 26.25 27.00 27.75 28.50 29.25 30.00 30.75 31.50 32.25 33.00 33.75 34.50 35.25 36.00 36.75 37.50 38.25 39.00 39.75 40.50 41.25 42.00 42.75 43.50 44.25 45.00 45.75 46.50 47.25 48.00 48.75 49.50 50.25 51.00 51.75 52.50 53.25 54.00 54.75 55.50 56.25 57.00 57.75 58.50 59.25 60.00 DW DW+SSE DW+T DW+T+SSE DW+T+Strat DW+T+Strat+SSE
Project Review Meeting: Advanced FEA Crack Growth Evaluations 58 May 8, 2007, North Bethesda, Maryland Plant-Specific Piping Loads Nominal Effective Bending Moment Load (Full Scale) 0 1000 2000 3000 4000 5000 6000 01 A - Re (7.75x5.17) 02 A - SA (7.75x5.17) 03 A - SB (7.75x5.17) 04 A - SC (7.75x5.17) 05 E - Re (7.75x5.17) 06 E - SA (7.75x5.17) 07 E - SB (7.75x5.17) 08 E - SC (7.75x5.17) 09 H - Re (7.75x5.17) 10 H - SA (7.75x5.17) 11 H - SB (7.75x5.17) 12 H - SC (7.75x5.17)
WC1 J - Re (7.75x5.17)
WC1a J - Re/Sa (7.75x5.17)
WC2 J - SA (7.75x5.17)
WC3 J - SB (7.75x5.17)
WC4 J - SC (7.75x5.17) 13 F - Re (8x5.19) 14 F - SA (8x5.19) 15 F - SB (8x5.19) 16 F - SC (8x5.19) 17 B - Re (7.75x5.62) 18 B - SA (7.75x5.62) 19 B - SB (7.75x5.62) 20 B - SC (7.75x5.62) 21 G - Re (7.75x5.62) 22 G - SA (7.75x5.62) 23 G - SB (7.75x5.62) 24 G - SC (7.75x5.62) 25 C - Re (7.75x5.62) 26 C - SA (7.75x5.62) 27 C - SB (7.75x5.62) 28 C - SC (7.75x5.62) 29 D - Re (8x5.19) 30 D - SA (8x5.19) 31 D - SB (8x5.19) 32 D - SC (8x5.19) 33 I - Re (8x5.188) 34 I - SA (8x5.188) 35 I - SB (8x5.188) 36 A - Sp (5.81x4.01) 37 E - Sp (5.81x4.01)
WC5 J - Sp (5.81x4.01) 38 B - Sp (5.81x4.25) 39 G - Sp (5.81x4.25) 40 C - Sp (5.81x4.25) 41 F - Sp (8x5.695) 42 D - Sp (5.188x3.062) 43 I - Sp (5.188x3.25) 44 A - Su (15x11.844) 45 E - Su (15x11.844) 46 H - Su (15x11.844)
WC6 J - Su (15x11.844) 47 B - Su (15x11.844) 48 G - Su (15x11.844) 49 C - Su (15x11.875) 50 D - Su (13.063x10.125) 51 I - Su (13.063x10.125)
Meff (in-kips) 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0.00 0.75 1.50 2.25 3.00 3.75 4.50 5.25 6.00 6.75 7.50 8.25 9.00 9.75 10.50 11.25 12.00 12.75 13.50 14.25 15.00 15.75 16.50 17.25 18.00 18.75 19.50 20.25 21.00 21.75 22.50 23.25 24.00 24.75 25.50 26.25 27.00 27.75 28.50 29.25 30.00 30.75 31.50 32.25 33.00 33.75 34.50 35.25 36.00 36.75 37.50 38.25 39.00 39.75 40.50 41.25 42.00 42.75 43.50 44.25 45.00 45.75 46.50 47.25 48.00 48.75 49.50 50.25 51.00 51.75 52.50 53.25 54.00 54.75 55.50 56.25 57.00 57.75 58.50 59.25 60.00 P+DW P+DW+SSE P+DW+T P+DW+T+SSE P+DW+T+Strat P+DW+T+Strat+SSE
Project Review Meeting: Advanced FEA Crack Growth Evaluations 59 May 8, 2007, North Bethesda, Maryland Plant-Specific Piping Loads Nominal Effective Bending Moment Load (Partial Scale) 0 100 200 300 400 500 600 700 800 01 A - Re (7.75x5.17) 02 A - SA (7.75x5.17) 03 A - SB (7.75x5.17) 04 A - SC (7.75x5.17) 05 E - Re (7.75x5.17) 06 E - SA (7.75x5.17) 07 E - SB (7.75x5.17) 08 E - SC (7.75x5.17) 09 H - Re (7.75x5.17) 10 H - SA (7.75x5.17) 11 H - SB (7.75x5.17) 12 H - SC (7.75x5.17)
WC1 J - Re (7.75x5.17)
WC1a J - Re/Sa (7.75x5.17)
WC2 J - SA (7.75x5.17)
WC3 J - SB (7.75x5.17)
WC4 J - SC (7.75x5.17) 13 F - Re (8x5.19) 14 F - SA (8x5.19) 15 F - SB (8x5.19) 16 F - SC (8x5.19) 17 B - Re (7.75x5.62) 18 B - SA (7.75x5.62) 19 B - SB (7.75x5.62) 20 B - SC (7.75x5.62) 21 G - Re (7.75x5.62) 22 G - SA (7.75x5.62) 23 G - SB (7.75x5.62) 24 G - SC (7.75x5.62) 25 C - Re (7.75x5.62) 26 C - SA (7.75x5.62) 27 C - SB (7.75x5.62) 28 C - SC (7.75x5.62) 29 D - Re (8x5.19) 30 D - SA (8x5.19) 31 D - SB (8x5.19) 32 D - SC (8x5.19) 33 I - Re (8x5.188) 34 I - SA (8x5.188) 35 I - SB (8x5.188) 36 A - Sp (5.81x4.01) 37 E - Sp (5.81x4.01)
WC5 J - Sp (5.81x4.01) 38 B - Sp (5.81x4.25) 39 G - Sp (5.81x4.25) 40 C - Sp (5.81x4.25) 41 F - Sp (8x5.695) 42 D - Sp (5.188x3.062) 43 I - Sp (5.188x3.25) 44 A - Su (15x11.844) 45 E - Su (15x11.844) 46 H - Su (15x11.844)
WC6 J - Su (15x11.844) 47 B - Su (15x11.844) 48 G - Su (15x11.844) 49 C - Su (15x11.875) 50 D - Su (13.063x10.125) 51 I - Su (13.063x10.125)
Meff (in-kips) 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0.00 0.75 1.50 2.25 3.00 3.75 4.50 5.25 6.00 6.75 7.50 8.25 9.00 9.75 10.50 11.25 12.00 12.75 13.50 14.25 15.00 15.75 16.50 17.25 18.00 18.75 19.50 20.25 21.00 21.75 22.50 23.25 24.00 24.75 25.50 26.25 27.00 27.75 28.50 29.25 30.00 30.75 31.50 32.25 33.00 33.75 34.50 35.25 36.00 36.75 37.50 38.25 39.00 39.75 40.50 41.25 42.00 42.75 43.50 44.25 45.00 45.75 46.50 47.25 48.00 48.75 49.50 50.25 51.00 51.75 52.50 53.25 54.00 54.75 55.50 56.25 57.00 57.75 58.50 59.25 60.00 P+DW P+DW+SSE P+DW+T P+DW+T+SSE P+DW+T+Strat P+DW+T+Strat+SSE
Project Review Meeting: Advanced FEA Crack Growth Evaluations 60 May 8, 2007, North Bethesda, Maryland Plant-Specific Piping Loads ASME Code Nominal Stress Loading for Pressure and Dead Weight Loading 0
4 8
12 16 01 A - Re (7.75x5.17) 02 A - SA (7.75x5.17) 03 A - SB (7.75x5.17) 04 A - SC (7.75x5.17) 05 E - Re (7.75x5.17) 06 E - SA (7.75x5.17) 07 E - SB (7.75x5.17) 08 E - SC (7.75x5.17) 09 H - Re (7.75x5.17) 10 H - SA (7.75x5.17) 11 H - SB (7.75x5.17) 12 H - SC (7.75x5.17)
WC1 J - Re (7.75x5.17)
WC1a J - Re/Sa (7.75x5.17)
WC2 J - SA (7.75x5.17)
WC3 J - SB (7.75x5.17)
WC4 J - SC (7.75x5.17) 13 F - Re (8x5.19) 14 F - SA (8x5.19) 15 F - SB (8x5.19) 16 F - SC (8x5.19) 17 B - Re (7.75x5.62) 18 B - SA (7.75x5.62) 19 B - SB (7.75x5.62) 20 B - SC (7.75x5.62) 21 G - Re (7.75x5.62) 22 G - SA (7.75x5.62) 23 G - SB (7.75x5.62) 24 G - SC (7.75x5.62) 25 C - Re (7.75x5.62) 26 C - SA (7.75x5.62) 27 C - SB (7.75x5.62) 28 C - SC (7.75x5.62) 29 D - Re (8x5.19) 30 D - SA (8x5.19) 31 D - SB (8x5.19) 32 D - SC (8x5.19) 33 I - Re (8x5.188) 34 I - SA (8x5.188) 35 I - SB (8x5.188) 36 A - Sp (5.81x4.01) 37 E - Sp (5.81x4.01)
WC5 J - Sp (5.81x4.01) 38 B - Sp (5.81x4.25) 39 G - Sp (5.81x4.25) 40 C - Sp (5.81x4.25) 41 F - Sp (8x5.695) 42 D - Sp (5.188x3.062) 43 I - Sp (5.188x3.25) 44 A - Su (15x11.844) 45 E - Su (15x11.844) 46 H - Su (15x11.844)
WC6 J - Su (15x11.844) 47 B - Su (15x11.844) 48 G - Su (15x11.844) 49 C - Su (15x11.875) 50 D - Su (13.063x10.125) 51 I - Su (13.063x10.125)
Pm, Pb, Pm +Pb Stress Loading (ksi) 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0.00 0.75 1.50 2.25 3.00 3.75 4.50 5.25 6.00 6.75 7.50 8.25 9.00 9.75 10.50 11.25 12.00 12.75 13.50 14.25 15.00 15.75 16.50 17.25 18.00 18.75 19.50 20.25 21.00 21.75 22.50 23.25 24.00 24.75 25.50 26.25 27.00 27.75 28.50 29.25 30.00 30.75 31.50 32.25 33.00 33.75 34.50 35.25 36.00 36.75 37.50 38.25 39.00 39.75 40.50 41.25 42.00 42.75 43.50 44.25 45.00 45.75 46.50 47.25 48.00 48.75 49.50 50.25 51.00 51.75 52.50 53.25 54.00 54.75 55.50 56.25 57.00 57.75 58.50 59.25 60.00 Pm Pm with SSE Pb Pb with SSE Pm+Pb Pm+Pb with SSE
Project Review Meeting: Advanced FEA Crack Growth Evaluations 61 May 8, 2007, North Bethesda, Maryland Plant-Specific Piping Loads ASME Code Nominal Stress Loading for Pressure, Dead Weight, and Normal Thermal Loading 0
5 10 15 20 01 A - Re (7.75x5.17) 02 A - SA (7.75x5.17) 03 A - SB (7.75x5.17) 04 A - SC (7.75x5.17) 05 E - Re (7.75x5.17) 06 E - SA (7.75x5.17) 07 E - SB (7.75x5.17) 08 E - SC (7.75x5.17) 09 H - Re (7.75x5.17) 10 H - SA (7.75x5.17) 11 H - SB (7.75x5.17) 12 H - SC (7.75x5.17)
WC1 J - Re (7.75x5.17)
WC1a J - Re/Sa (7.75x5.17)
WC2 J - SA (7.75x5.17)
WC3 J - SB (7.75x5.17)
WC4 J - SC (7.75x5.17) 13 F - Re (8x5.19) 14 F - SA (8x5.19) 15 F - SB (8x5.19) 16 F - SC (8x5.19) 17 B - Re (7.75x5.62) 18 B - SA (7.75x5.62) 19 B - SB (7.75x5.62) 20 B - SC (7.75x5.62) 21 G - Re (7.75x5.62) 22 G - SA (7.75x5.62) 23 G - SB (7.75x5.62) 24 G - SC (7.75x5.62) 25 C - Re (7.75x5.62) 26 C - SA (7.75x5.62) 27 C - SB (7.75x5.62) 28 C - SC (7.75x5.62) 29 D - Re (8x5.19) 30 D - SA (8x5.19) 31 D - SB (8x5.19) 32 D - SC (8x5.19) 33 I - Re (8x5.188) 34 I - SA (8x5.188) 35 I - SB (8x5.188) 36 A - Sp (5.81x4.01) 37 E - Sp (5.81x4.01)
WC5 J - Sp (5.81x4.01) 38 B - Sp (5.81x4.25) 39 G - Sp (5.81x4.25) 40 C - Sp (5.81x4.25) 41 F - Sp (8x5.695) 42 D - Sp (5.188x3.062) 43 I - Sp (5.188x3.25) 44 A - Su (15x11.844) 45 E - Su (15x11.844) 46 H - Su (15x11.844)
WC6 J - Su (15x11.844) 47 B - Su (15x11.844) 48 G - Su (15x11.844) 49 C - Su (15x11.875) 50 D - Su (13.063x10.125) 51 I - Su (13.063x10.125)
Pm, Pb, Pm +Pb Stress Loading (ksi) 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0.00 0.75 1.50 2.25 3.00 3.75 4.50 5.25 6.00 6.75 7.50 8.25 9.00 9.75 10.50 11.25 12.00 12.75 13.50 14.25 15.00 15.75 16.50 17.25 18.00 18.75 19.50 20.25 21.00 21.75 22.50 23.25 24.00 24.75 25.50 26.25 27.00 27.75 28.50 29.25 30.00 30.75 31.50 32.25 33.00 33.75 34.50 35.25 36.00 36.75 37.50 38.25 39.00 39.75 40.50 41.25 42.00 42.75 43.50 44.25 45.00 45.75 46.50 47.25 48.00 48.75 49.50 50.25 51.00 51.75 52.50 53.25 54.00 54.75 55.50 56.25 57.00 57.75 58.50 59.25 60.00 Pm Pm with SSE Pb Pb with SSE Pm+Pb Pm+Pb with SSE
Project Review Meeting: Advanced FEA Crack Growth Evaluations 62 May 8, 2007, North Bethesda, Maryland Plant-Specific Piping Loads ASME Nominal Stress Loading for Pressure, Dead Weight, Normal Thermal, and Normal Thermal Stratification Loading 0
5 10 15 20 25 30 35 40 01 A - Re (7.75x5.17) 02 A - SA (7.75x5.17) 03 A - SB (7.75x5.17) 04 A - SC (7.75x5.17) 05 E - Re (7.75x5.17) 06 E - SA (7.75x5.17) 07 E - SB (7.75x5.17) 08 E - SC (7.75x5.17) 09 H - Re (7.75x5.17) 10 H - SA (7.75x5.17) 11 H - SB (7.75x5.17) 12 H - SC (7.75x5.17)
WC1 J - Re (7.75x5.17)
WC1a J - Re/Sa (7.75x5.17)
WC2 J - SA (7.75x5.17)
WC3 J - SB (7.75x5.17)
WC4 J - SC (7.75x5.17) 13 F - Re (8x5.19) 14 F - SA (8x5.19) 15 F - SB (8x5.19) 16 F - SC (8x5.19) 17 B - Re (7.75x5.62) 18 B - SA (7.75x5.62) 19 B - SB (7.75x5.62) 20 B - SC (7.75x5.62) 21 G - Re (7.75x5.62) 22 G - SA (7.75x5.62) 23 G - SB (7.75x5.62) 24 G - SC (7.75x5.62) 25 C - Re (7.75x5.62) 26 C - SA (7.75x5.62) 27 C - SB (7.75x5.62) 28 C - SC (7.75x5.62) 29 D - Re (8x5.19) 30 D - SA (8x5.19) 31 D - SB (8x5.19) 32 D - SC (8x5.19) 33 I - Re (8x5.188) 34 I - SA (8x5.188) 35 I - SB (8x5.188) 36 A - Sp (5.81x4.01) 37 E - Sp (5.81x4.01)
WC5 J - Sp (5.81x4.01) 38 B - Sp (5.81x4.25) 39 G - Sp (5.81x4.25) 40 C - Sp (5.81x4.25) 41 F - Sp (8x5.695) 42 D - Sp (5.188x3.062) 43 I - Sp (5.188x3.25) 44 A - Su (15x11.844) 45 E - Su (15x11.844) 46 H - Su (15x11.844)
WC6 J - Su (15x11.844) 47 B - Su (15x11.844) 48 G - Su (15x11.844) 49 C - Su (15x11.875) 50 D - Su (13.063x10.125) 51 I - Su (13.063x10.125)
Pm, Pb, Pm +Pb Stress Loading (ksi) 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0.00 0.75 1.50 2.25 3.00 3.75 4.50 5.25 6.00 6.75 7.50 8.25 9.00 9.75 10.50 11.25 12.00 12.75 13.50 14.25 15.00 15.75 16.50 17.25 18.00 18.75 19.50 20.25 21.00 21.75 22.50 23.25 24.00 24.75 25.50 26.25 27.00 27.75 28.50 29.25 30.00 30.75 31.50 32.25 33.00 33.75 34.50 35.25 36.00 36.75 37.50 38.25 39.00 39.75 40.50 41.25 42.00 42.75 43.50 44.25 45.00 45.75 46.50 47.25 48.00 48.75 49.50 50.25 51.00 51.75 52.50 53.25 54.00 54.75 55.50 56.25 57.00 57.75 58.50 59.25 60.00 Pm Pm with SSE Pb Pb with SSE Pm+Pb Pm+Pb with SSE
Project Review Meeting: Advanced FEA Crack Growth Evaluations 63 May 8, 2007, North Bethesda, Maryland Plant-Specific Piping Loads Treatment of Loads in Crack Growth Modeling Each category of loading be treated as follows in the crack growth calculation:
- Deadweight: Axial force and bending moment applied to end of model
- Internal pressure: End cap axial force based on ID at weld, plus full crack face pressure applied directly to crack face for surface and through-wall cracks
- Normal pipe thermal expansion: Axial force and bending moment applied to end of model (no credit taken for relaxation of load with crack opening)
- Normal thermal stratification pipe bending moment (surge nozzle only): Added to normal thermal loads
- Thermal stratification pipe bending moment for plant transients (surge nozzle only): Not relevant for crack growth
- Welding residual stress: Multiple cases assumed as described separately below
- Local thermal stress due to differential thermal expansion (Q-stress): Considered as a sensitivity case in cracked WRS model
- Seismic loads: Not relevant for crack growth
Project Review Meeting: Advanced FEA Crack Growth Evaluations 64 May 8, 2007, North Bethesda, Maryland Plant-Specific Piping Loads Treatment of Loads in Crack Growth Modeling (contd)
For global moment loads, the following equation (NUREG/CR-6299) is being used to calculate an effective global bending moment:
The equation considers the effect of the applied torsion on the Von Mises effective stress This is a simplification as torsion would act as a Mode II and/or III loading on the crack 2
2 2
3 2
eff y
z M
M M
T
=
+
+
Project Review Meeting: Advanced FEA Crack Growth Evaluations 65 May 8, 2007, North Bethesda, Maryland Proposed Case Matrix Welding Residual Stress Summary of May 1 Meeting Fabrication Steps affecting WRS
- Last Pass Fill-In Weld (Surge)
- Fillet Welds (Safety/Relief)
- Buildup on Safe End ID Repairs
- Deep ID Repairs
- ID Repairs on Spray Nozzle?
Project Review Meeting: Advanced FEA Crack Growth Evaluations 66 May 8, 2007, North Bethesda, Maryland Welding Residual Stress Agenda of May 1 Meeting at DEI Offices Nozzle and weld geometry cases for subject welds Collected weld repair information for subject welds Application of WRS FEA models
- Previous FEA results by DEI (MRP-106)
- FEA work by Battelle and EMC2 (presentation by Dave Rudland, EMC2)
- Discussion of approach to new FEA for selected subject weld cases WRS data for piping butt welds in open literature Candidate WRS profiles
- Axisymmetric profiles
- Non-axisymmetric profiles Validation of WRS inputs Meeting wrap-up
Project Review Meeting: Advanced FEA Crack Growth Evaluations 67 May 8, 2007, North Bethesda, Maryland Proposed Case Matrix Tentative New FEA WRS Cases Planned at May 1 Meeting Effect of SS weld on stress in DM weld
- One axisymmetric case to be selected based on design and available as-built weld separation data
- Influence is expected to depend on x/t and Ri/t, where x is the weld separation distance Surge nozzle cases
- No repairs with fill-in weld
- 0.5 deep ID repair followed by fill-in weld
- CE nozzle case with no fill-in weld Spray nozzle cases
- Consider deferring until Plant C and F weld repair records are searched Safety/relief nozzle cases
- Model effect of 1/8 weld buildup on safe end ID (geometry based on WC)
- No repairs with liner fillet weld
- 3/4 deep ID repair followed by liner fillet weld Consider modeling short, deep repairs using 3D model
Project Review Meeting: Advanced FEA Crack Growth Evaluations 68 May 8, 2007, North Bethesda, Maryland Development of WRS Cases Approach Because of the uncertainty in the true residual stress field in each of the 51 subject welds, a matrix of sensitivity cases will be considered covering a wide range of WRS patterns Range of welding residual stress profiles
- Axisymmetric (self balance at every circumferential position)
- Non-axisymmetric (self balance over entire cross section)
- Weld fabrication and repair data compiled as input to selection of WRS profiles for analysis As previously planned, the following sources will be applied to develop the WRS cases considered:
- Weld fabrication and repair data from construction for the 51 subject welds
- Previous WRS calculations by DEI and others for PWR piping butt welds
- Limited number of DEI WRS FEA model runs for the specific geometry of some of the 51 subject welds considering the weld fabrication information
- WRS data in the open literature FEA simulations Stress measurements on mockups and removed components
Project Review Meeting: Advanced FEA Crack Growth Evaluations 69 May 8, 2007, North Bethesda, Maryland Development of WRS Cases Approach (contd)
Patterns of WRS variability will be considered in both the radial and circumferential directions For the cylindrical shell SIF model, the WRS will be simulated using an applied thermal input pattern, which may vary in the radial and circumferential directions
- Simulation of WRS using thermal strains is a standard technique
- The axial extent of the applied temperature load will be conservatively chosen based on the design length of the DM weld
- This length will be varied in sensitivity cases to check for the effect of residual stress relaxation For selected sensitivity cases of the optional SIF modeling, the 3-dimensional WRS field from the DEI intact WRS FEA model will be directly input to the cracked SIF model
Project Review Meeting: Advanced FEA Crack Growth Evaluations 70 May 8, 2007, North Bethesda, Maryland Welding Residual Stress Inputs Weld Fabrication and Repair Data Compiled for Wolf Creek Available data on initial weld fabrication and repair has also been compiled for the subject welds
- See next two slides Source: MRP 2007-003 Attachment 1 (White Paper).
Project Review Meeting: Advanced FEA Crack Growth Evaluations 71 May 8, 2007, North Bethesda, Maryland Nozzle Geometry and Repair History PRELIMINARY Weld Repair Summary Table Table Line Plant Code Nozzle Type Nozzle Count Design Buttering or Weld Length (in.)
Depth (in.)
Length (in.)
Depth (in.)
Length (in.)
Depth (in.)
Length (in.)
Depth (in.)
Length (in.)
Depth (in.)
Length (in.)
Depth (in.)
1 A
Safety A 1
N/A
~1/2 N/A
~1/2 N/A
~1/2 N/A
~1/2 2
A Safety B 2
1a weld ID N/A N/A 1
1/2 5/8 3
E Relief 3
N/A N/A N/A 4
E Safety C 4
1a weld ID<22%
N/A N
N/A N/A N/A 5
ID 82 Y
N/A N/A N/A 6
OD 82 Y
N/A N/A N/A 7
F Safety A 6
1b NR NR NR NR NR NR NR 8
B Relief 7
0.5 0.375 9
C Safety A 8
2b NR NR NR NR NR NR NR 10 C
Safety B 9
2b NR NR NR NR NR NR NR 11 C
Safety C 10 2b NR NR NR NR NR NR NR 12 D
Safety A 11 3
butter N/A N/A Y
N/A N/A N/A 13 butter ID 82 Y
N/A N/A
N/A N/A N/A 15 C
Spray 13 5
NR NR NR NR NR NR NR 16 ID N/A N/A 5
1.5 5/16 3.75 0.5 2
3/16 2.5 5/16 2
5/16 17 OD N/A N/A 3
2.5 0.5 2
0.5 1
3/16 18 E
Surge 15 8
weld ID<10%
82 N
3 N/A N/A N/A N/A N/A N/A 19 butter N/A 82 Y
1 N/A N/A 20 OD 182 N/A 2
1.75 0.875 1.5 1
21 ID 182 N/A 1
1.0 0.625 22 ID 182 N/A 1
4 0.75 Notes:
- 1. For Designs #2a, #2b, and #5, liner directly covers DM weld.
- 2. For Design #4, liner does not extend to most of DM weld.
- 5. NR = Information not yet reported (or may not be available)
- 6. N/A = Information not available
- 7. Weld repair entries for Plants C and F are preliminary.
PWHT after Repair?
Alloy 82 or 182
- Defect or Repair Areas Defect/Repair Area #6 Defect/Repair Area #4 Defect/Repair Area #5 Defect/Repair Area #1 Defect/Repair Area #2 Defect/Repair Area #3 Safety A H
1a weld 5
E Spray 4
A Surge 8
12 weld weld B
Surge 8
14 16 ID/OD
(%
circ.)
Project Review Meeting: Advanced FEA Crack Growth Evaluations 72 May 8, 2007, North Bethesda, Maryland Nozzle Geometry and Repair History PRELIMINARY Weld Repair Summary Table (contd)
Table Line Plant Code Nozzle Type Nozzle Count Design Buttering or Weld Length (in.)
Depth (in.)
Length (in.)
Depth (in.)
Length (in.)
Depth (in.)
Length (in.)
Depth (in.)
Length (in.)
Depth (in.)
Length (in.)
Depth (in.)
WC1 N/A 82/182 Y
N/A N/A N/A WC2 ID+OD 82 Y
2 1/2 7/16ID 1
7/16OD WC3 OD 182 Y
1 1
3/4 WC4 ID 82 Y
3 3/4 3/4 2-1/4 3/4 1/2 3/4 WC5 OD 182 Y
3 1
3/4 2-1/4 3/4 1/2 3/4 WC6 OD 82 N/A 1
1-1/4 1/2 WC7 ID 82 N/A 1
1/2 1/2 WC8 butter N/A 182 Y
N/A N/A 1/8 WC9 weld ID 82 N/A 2
1-1/4 11/32 7/8 11/32 WC10 82 N/A 6
2-1/2 3/4 1
1/2 1-1/2 1/2 1
1/2 2-1/2 3/4 2-1/2 3/4 WC11 82 N/A 6
1-1/2 1/2 1-1/4 1
3/4 7/8 1-1/2 3/8 1
1-1/16 1/2 1/2 WC12 J
Spray WC4 4
butter lip/bondline 82 Y
N/A N/A N/A WC13 butter OD 182 Y
2 7/8 9/16 1-1/8 1
WC14 weld ID 82 Y
1 1
7/16 Notes:
- 1. For Designs #2a, #2b, and #5, liner directly covers DM weld.
- 2. For Design #4, liner does not extend to most of DM weld.
- 5. NR = Information not yet reported (or may not be available)
- 6. N/A = Information not available
- 7. Weld repair entries for Plants C and F are preliminary.
PWHT after Repair?
Alloy 82 or 182
- Defect or Repair Areas Defect/Repair Area #6 Defect/Repair Area #4 Defect/Repair Area #5 Defect/Repair Area #1 Defect/Repair Area #2 Defect/Repair Area #3 weld J
Relief 1a WC1 1a J
Surge 8
WC2 WC5 ID/OD
(%
circ.)
J Safety B WC3 1a weld ID butter J
Safety A
Project Review Meeting: Advanced FEA Crack Growth Evaluations 73 May 8, 2007, North Bethesda, Maryland Welding Residual Stress Conclusions of Previous DEI Work for EPRI (MRP-106, etc.)
Welding residual stresses are high and a significant contributor to butt weld PWSCC The generic welding residual stress model is conservative for the as-designed case without repairs Weld repairs from the ID surface (360° or partial-arc) significantly increase ID surface stresses
- Generic welding residual stress model does not bound FEA results for cases involving repairs from the ID surface Deep partial-arc weld repairs from the OD surface have high restraint and may produce similar through-wall stress distributions as for cases of ID repairs depending on depth of repair
- Generic welding residual stress model does not bound FEA results for some cases involving partial-arc repairs from the OD surface High stresses for cases involving partial-arc repairs are limited to the repaired area
- Expected to produce cracks limited to the repaired area, not 360°
Project Review Meeting: Advanced FEA Crack Growth Evaluations 74 May 8, 2007, North Bethesda, Maryland Piping Butt Weld WRS - Literature Review Preliminary Conclusions Piping Butt Welds Without Repairs:
- Stress measurements show that welding start/stops can produce variations in axial and hoop stress on the order of or greater than the material yield strength over circumferential arc lengths of 15° to 20° Piping Butt Welds With Repairs:
- Weld repairs generally increase the magnitude of maximum tensile axial residual stress
- Location of maximum axial tensile stresses can be in the repair zone or possibly opposite the repair zone depending on the location of the repair relative to the original weld start/stop location
- Weld cap removal provides little benefit in reducing welding residual stresses, particularly on the weld ID
- Short, deep repairs generally result in greater increases in axial tensile residual stresses
Project Review Meeting: Advanced FEA Crack Growth Evaluations 75 May 8, 2007, North Bethesda, Maryland Validation of WRS Inputs Approach A two-step process to model validation is envisioned:
- Validation of residual stress assumptions based on available stress measurements, model predictions, and the general WRS literature
- Validation of the overall crack growth model based on available destructive examinations results for weld metal applications and other information Various sources of WRS information will be sorted and organized to support range of WRS cases considered in the calculations:
- Mockup stress measurements
- Stress measurements on removed plant components
- Various FEA models including DEI, SI, EMC2, etc.
- General WRS literature
- International round robin, if needed details can be made available
Project Review Meeting: Advanced FEA Crack Growth Evaluations 76 May 8, 2007, North Bethesda, Maryland Validation of WRS Inputs Approach (contd)
In past comparisons, the results of the DEI WRS model have shown reasonable agreement versus measured WRS:
- Measured CRDM nozzle mockup stress
- Measured BWR shroud support weld stress
- Measured CRDM nozzle ovality
Project Review Meeting: Advanced FEA Crack Growth Evaluations 77 May 8, 2007, North Bethesda, Maryland Proposed Case Matrix Crack Growth Rate Equation Sensitivity cases will examine the effect of main uncertainties in the MRP-115 CGR equation:
- Uncertainty in the SIF power-law exponent (nominal 1.6)
- Uncertainty in power-law constant (only time scaling factor that would affect time between leakage and rupture but not whether leakage prior to rupture)
The following factors are not expected to be explicitly evaluated using the FEACrack software
- Lower CGR for Alloy 82 root passes versus Alloy 182 passes (factor of 2.6)
- Lower CGR for growth perpendicular to dendrite solidification direction (factor of 2.0)
No credit being taken for a SIF threshold
Project Review Meeting: Advanced FEA Crack Growth Evaluations 78 May 8, 2007, North Bethesda, Maryland MRP-115 Crack Growth Rate Equation Screened MRP Lab CGR Database for Alloys 82/182/132 Average CGR data for Alloys 182/132 after screening (43 points)
Average CGR data for Alloy 82 after screening (34 points) 1.E-12 1.E-11 1.E-10 1.E-09 1.E-08 0
10 20 30 40 50 60 70 80 Stress Intensity Factor, K (MPam)
Crack Growth Rate, da /dt (m/s) 1mm/yr MRP-55 Curve for Alloy 600 MRP-21 Curve for Alloy 182 All CGRs are adjusted to account for percentage engagement across the crack front but not alloy type or crack orientation 1.E-12 1.E-11 1.E-10 1.E-09 1.E-08 0
10 20 30 40 50 60 70 80 Stress Intensity Factor, K (MPam)
Crack Growth Rate, da /dt (m/s) 1mm/yr MRP-55 Curve for Alloy 600 MRP-21 Curve for Alloy 182 All CGRs are adjusted to account for percentage engagement across the crack front but not alloy type or crack orientation
Project Review Meeting: Advanced FEA Crack Growth Evaluations 79 May 8, 2007, North Bethesda, Maryland MRP-115 Crack Growth Rate Equation Distribution of Screened Data by Weld Factor 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0.1 1.
10.
Weld Factor, f weld Cumulative Distribution F 9 182 Welds 8 82 Welds 2 132 Welds Log-Normal Fit Weld factors for 19 welds of Alloy 82/182/132 material with fit log-normal distribution (most likely estimator), K th = 0, and best fit 25th Percentile 75th Percentile Median The Alloy 82 data have been normalized (increased) by applying a factor of 2.61:
1/f alloy = 2.61 The variability in weld factor from the statistical evaluations of laboratory CGR data in MRP-115 will be used to investigate the effect of uncertainty in the power-law constant
Project Review Meeting: Advanced FEA Crack Growth Evaluations 80 May 8, 2007, North Bethesda, Maryland MRP-115 Crack Growth Rate Equation Recommended Disposition Curves (325°C) 1.E-12 1.E-11 1.E-10 1.E-09 1.E-08 0
10 20 30 40 50 60 70 80 Stress Intensity Factor, K (MPam)
Crack Growth Rate, da /dt (m/s)
The reference temperature for the MRP curves is 325°C (617°F); the recommended thermal activation energy for temperature adjustment is 130 kJ/mole (31.0 kcal/mole),
the same value recommended in MRP-55 for base metal.
1 mm/yr MRP-115 Curve for Alloy 182/132 CGR = 1.5x10-12K 1.6 MRP-115 Curve for Alloy 82 CGR = (1.5x10-12/2.6)K 1.6 For crack propagation that is clearly perpendicular to the dendrite solidification direction, a factor of 2.0 lowering the CGR may be applied to the curves for Alloy 182 (or 132) and Alloy 82.
MRP-55 Curve for Alloy 600 Base Metal Laboratory testing indicates that the CGR for Alloy 82 is on average 2.6 times lower than that for Alloy 182/132, so the MRP-115 curve for Alloy 82 is 2.6 times lower than the curve for Alloy 182/132.
Project Review Meeting: Advanced FEA Crack Growth Evaluations 81 May 8, 2007, North Bethesda, Maryland Proposed Case Matrix Effect of Multiple Cracks As demonstrated by practical experience such as apparently for the Wolf Creek pressurizer surge nozzle, there is the possibility of multiple growing flaws connected to the weld ID Sensitivity cases will investigate the effect of multiple crack initiation Several potential approaches are being considered:
- Enveloping of multiple initial flaws with one modeled flaw
- Modeling of a part-depth 360° flaw with a variable depth around the circumference
- Static FEA SIF modeling of two separated flaws to investigate influence of each flaw on the other as a function of their separation on the weld ID See Quest Reliability, LLC slides on this topic
Crack Interaction Greg Thorwald, Ph.D.
303-415-1475
Coplanar Cracks Fig 2.57 Two Coplanar cracks, interaction magnifies KI at nearest crack tips
Crack Tip Interaction Fig. 2.58 Interaction of two identical coplanar through-wall cracks in an infinite plate; KI magnified at crack tip B
Parallel Cracks Fig. 2.59 Parallel cracks; shielding causes decrease in KI
Parallel Crack Shielding Fig. 2.60 Interaction between two identical parallel through-wall cracks in an infinite plate; crack tip shielding decreases KI compared to a single crack
Crack Interaction Models
Use a single crack and a symmetry plane near the crack tip to get K interaction
Include multiple cracks in a model
User-defined geometry method from FEACrack
- Same or different crack shapes
- Adjust distance between crack fronts
Project Review Meeting: Advanced FEA Crack Growth Evaluations 82 May 8, 2007, North Bethesda, Maryland Proposed Case Matrix Other Items: Initial Flaw Geometry Sensitivity cases will investigate the effect of initial flaw geometry
- Initial depth
- Initial aspect ratio (2c/a) or 360° uniform depth surface flaw
- Initial shape factor (e.g., low shape factor to semi-ellipse to close to uniform depth)
Cases for WC relief nozzle dimensions indicate that crack profile upon through-wall penetration (or upon crack arrest) is insensitive to initial flaw geometry
Project Review Meeting: Advanced FEA Crack Growth Evaluations 83 May 8, 2007, North Bethesda, Maryland Proposed Case Matrix Other Items: Effect of Elastic-Plastic Redistribution of Load Cases to investigate effect of elastic-plastic redistribution of load given high WRS at ID surface
- The applied WRS profile may be modified to investigate this effect as implied in the following figure:
-30
-20
-10 0
10 20 30 40 50 60 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 Normalized Distance from ID Surface, (r-ri)/t Axial Stress with Residual Stress (ksi) 0° 22.5° 45° 67.5° 90° 112.5° 135° 157.5° 180°
= 0° to 180°
= 0° is circumferential position of maximum bending axial stress;
= 90° is bending neutral axis Plot for WC relief nozzle showing axial stress profile at various positions around circumference (dead weight, thermal pipe load, end cap pressure, and assumed WRS) example of possible stress profile based on modified WRS
Project Review Meeting: Advanced FEA Crack Growth Evaluations 84 May 8, 2007, North Bethesda, Maryland Proposed Case Matrix Other Items: Crack Inserted into WRS FEA Model It is planned for selected sensitivity cases, a crack will be inserted directly into the 3-dimensional DEI WRS FEA model
- Considers detailed geometry effects
- Considers detailed predicted WRS field, including modeling of weld repairs
- Considers local thermal stress due to differential thermal expansion (Q-stress)
Project Review Meeting: Advanced FEA Crack Growth Evaluations 85 May 8, 2007, North Bethesda, Maryland Proposed Case Matrix Other Items: Crack Inserted into WRS FEA Model This type of approach was applied in a preliminary fashion by DEI in 2005 for a reactor pressure vessel outlet nozzle The FEACrack enhancement for this work will reduce the effort required to insert the crack mesh into the full welding residual stress model 1
RPV Outlet Nozzle 90 Degree ID R - Operating Conditions 1
RV Outlet Nozzle ID90 Repair - 20% TW Crack, 6:1 Aspect Ratio Intact Axial Operating Stresses Axial Stress Redistribution with Circ Crack
Project Review Meeting: Advanced FEA Crack Growth Evaluations 86 May 8, 2007, North Bethesda, Maryland Additional Topics - Industry and NRC Critical Crack Size Calculations
- Industry Validation studies and WRS mockups
- Industry Benchmarking NRC/Industry K Solutions for the Advanced FEA Calculations
- Industry
- NRC Leak-rate Calculations
- Industry
Project Review Meeting: Advanced FEA Crack Growth Evaluations 87 May 8, 2007, North Bethesda, Maryland Calculating Critical Crack Size Approach Scoping calculations have been completed examining the dependence of critical crack size for idealized surface and through-wall crack geometries for the dimensions and load parameters for the group of 51 subject welds
- Effect of load types included
- Effect of assumed flow strength
- Effect of thin-wall vs. thick-wall equations
- Effect of surface vs. through-wall crack geometry
- Effect of inclusion of Z-factor The flow strength in the net section collapse calculations will be based on the safe end material, given the potential for the crack to be located close to the safe end Crack stability for each calculated crack growth progression (surface crack and through-wall) is being checked using a spreadsheet implementation of the NSC solution published by Rahman and Wilkowski for an arbitrary crack profile, assuming thin-wall equilibrium
Project Review Meeting: Advanced FEA Crack Growth Evaluations 88 May 8, 2007, North Bethesda, Maryland Calculating Critical Crack Size Approach (contd)
The Arbitrary Net Section Collapse (ANSC) software by Structural Integrity Associates is also being applied:
- To verify the spreadsheet implementation of Rahman and Wilkowski (exact agreement has been obtained)
- To investigate cases in which the moment direction is not assumed to be lined up with the symmetry (i.e., center) point on the crack Consider secondary stresses as appropriate
- See separate presentation by Pete Riccardella of SI Apply Z-factor to reduce supportable moment to consider effect of EPFM failure mechanism for small calculated values of the nondimensional plastic zone parameter
- See separate presentation by Pete Riccardella of SI As described above, the crack growth progression is also checked for the potential effect of local ligament collapse
- For complex crack profile at point leakage becomes detectable
- For complete growth progression to examine potential effect on the progression
Project Review Meeting: Advanced FEA Crack Growth Evaluations 89 May 8, 2007, North Bethesda, Maryland Calculating Critical Crack Size Defining Pipe Loads for Critical Crack Size Each category of loading is being treated as follows in the critical crack size calculation that defines the growth end point:
- Deadweight: Same as for growth
- Internal pressure: Same as for growth
- Normal pipe thermal expansion: Treatment of secondary stresses discussed in presentation slides by Pete Riccardella of SI
- Normal thermal stratification pipe bending moment (surge nozzle only): Treatment of secondary stresses discussed in presentation slides by Pete Riccardella of SI
- Thermal stratification pipe bending moment for plant transients (surge nozzle only):
Treatment of secondary stresses discussed in presentation slides by Pete Riccardella of SI
- Welding residual stress: Not included in limit load or EPFM mechanisms
- Local thermal stress due to differential thermal expansion (Q-stress): Not included as this is a local secondary stress component
- Seismic loads: SSE load considered for faulted cases
Project Review Meeting: Advanced FEA Crack Growth Evaluations 90 May 8, 2007, North Bethesda, Maryland Calculating Critical Crack Size Force and Moment Equilibrium for Arbitrary Crack Rahman and Wilkowski have published the thin-wall solution for axial force and applied moment equilibrium given a circumferential flaw with arbitrary depth profile DEI has implemented this solution in spreadsheet form The solution is being applied to crack profiles calculated by the FEACrack software Case 1: Entire crack in tension Case 2a: Part of crack in compression zone with crack taking compression Case 2b: Part of crack in compression zone with crack not taking compression Arbitrary Net Section Collapse (ANSC) software by Structural Integrity Associates used to validate spreadsheet calculation ANSC also allows arbitrary moment direction, unlike Rahman and Wilkowski S. Rahman and G. Wilkowski, Net-Section-Collapse Analysis of Circumferentially Cracked CylindersPart I: Arbitrary-Shaped Cracks and Generalized Equations, Engineering Fracture Mechanics, Vol. 61, pp. 191-211, 1998.
Project Review Meeting: Advanced FEA Crack Growth Evaluations 91 May 8, 2007, North Bethesda, Maryland Calculating Critical Crack Size Safe End Flow Strength Because any hypothetical SCC could be located close to the safe end material, the safe end flow strength will be applied in the limit load crack stability calculations Design drawings and CMTR information for 9 subject plants indicate that the stainless steel safe ends are fabricated from the following materials:
- SA182 Grade F316L in most cases
- SA182 Grade F316 in the other cases The following two slides show application of CMTR data to determine likely range of flow strength at temperature for the subject safe ends
- Flow strength taken as average of yield and ultimate strength
- Assumed temperature dependence between room temperature and 650°F based on Code temperature dependences for these materials: S650°F = CMTRx(Code650°F/CodeRT)
The results of this investigation support the use of the 45.6 ksi flow strength value assumed in the NRC calculations for the WC safe end
Project Review Meeting: Advanced FEA Crack Growth Evaluations 92 May 8, 2007, North Bethesda, Maryland Calculating Critical Crack Size CMTR Strength Values for Safe Ends 0
10 20 30 40 50 60 70 80 01 A - Re (7.75x5.17) 02 A - SA (7.75x5.17) 03 A - SB (7.75x5.17) 04 A - SC (7.75x5.17) 05 E - Re (7.75x5.17) 06 E - SA (7.75x5.17) 07 E - SB (7.75x5.17) 08 E - SC (7.75x5.17) 09 H - Re (7.75x5.17) 10 H - SA (7.75x5.17) 11 H - SB (7.75x5.17) 12 H - SC (7.75x5.17)
WC1 J - Re (7.75x5.17) 14 F - SA (8x5.19) 15 F - SB (8x5.19) 16 F - SC (8x5.19) 17 B - Re (7.75x5.62) 18 B - SA (7.75x5.62) 19 B - SB (7.75x5.62) 20 B - SC (7.75x5.62) 21 G - Re (7.75x5.62) 22 G - SA (7.75x5.62) 23 G - SB (7.75x5.62) 24 G - SC (7.75x5.62) 25 C - Re (7.75x5.62) 26 C - SA (7.75x5.62) 27 C - SB (7.75x5.62) 28 C - SC (7.75x5.62) 29 D - Re (8x4.937) 30 D - SA (8x4.937) 31 D - SB (8x4.937) 32 D - SC (8x4.937) 33 I - Re (8x4.937) 34 I - SA (8x4.937) 35 I - SB (8x4.937) 36 A - Sp (5.81x4.01) 37 E - Sp (5.81x4.01)
WC5 J - Sp (5.81x4.01) 39 G - Sp (5.81x4.25) 40 C - Sp (5.81x4.25) 41 F - Sp (8x5.695) 42 D - Sp (5.188x3.062) 43 I - Sp (5.188x3.25) 44 A - Su (15x11.844) 45 E - Su (15x11.844) 46 H - Su (15x11.844)
WC6 J - Su (15x11.844) 48 G - Su (15x11.844) 49 C - Su (15x11.875) 50 D - Su (13.063x10.125) 51 I - Su (13.063x10.125)
CMTR Safe End Strength Values (ksi) 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0.00 0.50 1.00 1.50 2.00 2.50 3.00 4.75 5.25 5.75 6.25 6.75 7.25 7.75 8.25 8.75 9.25 9.75 10.25 11.00 11.50 12.00 12.50 13.00 13.75 14.25 14.75 15.25 15.75 16.25 16.75 17.25 17.75 18.25 18.75 19.25 19.75 20.25 20.75 21.25 21.75 22.25 22.75 23.25 23.75 24.25 24.75 25.25 25.75 26.25 26.75 27.25 27.75 28.25 28.75 29.25 29.75 30.25 30.75 31.25 31.75 32.25 32.75 33.25 33.75 34.25 34.75 35.25 35.75 36.25 36.75 37.25 37.75 38.25 38.75 39.25 39.75 40.25 40.75 41.25 41.75 42.25 42.75 43.25 43.75 44.25 44.75 45.25 45.75 46.25 46.75 47.25 47.75 48.25 48.75 49.25 49.75 50.25 50.75 51.25 51.75 52.25 52.75 53.25 53.75 54.25 54.75 55.25 55.75 56.25 56.75 57.25 57.75 58.25 58.75 59.25 59.75 CMTR UTS CMTR FS CMTR YS Flow strength (FS) taken as average of YS and UTS listed in safe end CMTR.
Project Review Meeting: Advanced FEA Crack Growth Evaluations 93 May 8, 2007, North Bethesda, Maryland Calculating Critical Crack Size Estimated Safe End Flow Strength at 650°F 0
10 20 30 40 50 60 70 80 01 A - Re (7.75x5.17) 02 A - SA (7.75x5.17) 03 A - SB (7.75x5.17) 04 A - SC (7.75x5.17) 05 E - Re (7.75x5.17) 06 E - SA (7.75x5.17) 07 E - SB (7.75x5.17) 08 E - SC (7.75x5.17) 09 H - Re (7.75x5.17) 10 H - SA (7.75x5.17) 11 H - SB (7.75x5.17) 12 H - SC (7.75x5.17)
WC1 J - Re (7.75x5.17) 14 F - SA (8x5.19) 15 F - SB (8x5.19) 16 F - SC (8x5.19) 17 B - Re (7.75x5.62) 18 B - SA (7.75x5.62) 19 B - SB (7.75x5.62) 20 B - SC (7.75x5.62) 21 G - Re (7.75x5.62) 22 G - SA (7.75x5.62) 23 G - SB (7.75x5.62) 24 G - SC (7.75x5.62) 25 C - Re (7.75x5.62) 26 C - SA (7.75x5.62) 27 C - SB (7.75x5.62) 28 C - SC (7.75x5.62) 29 D - Re (8x4.937) 30 D - SA (8x4.937) 31 D - SB (8x4.937) 32 D - SC (8x4.937) 33 I - Re (8x4.937) 34 I - SA (8x4.937) 35 I - SB (8x4.937) 36 A - Sp (5.81x4.01) 37 E - Sp (5.81x4.01)
WC5 J - Sp (5.81x4.01) 39 G - Sp (5.81x4.25) 40 C - Sp (5.81x4.25) 41 F - Sp (8x5.695) 42 D - Sp (5.188x3.062) 43 I - Sp (5.188x3.25) 44 A - Su (15x11.844) 45 E - Su (15x11.844) 46 H - Su (15x11.844)
WC6 J - Su (15x11.844) 48 G - Su (15x11.844) 49 C - Su (15x11.875) 50 D - Su (13.063x10.125) 51 I - Su (13.063x10.125)
Safe End Strength Values (ksi) at 650°F Based on CMTR Data 0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0.00 0.75 1.50 2.25 3.00 5.00 5.75 6.50 7.25 8.00 8.75 9.50 10.25 11.25 12.00 12.75 13.75 14.50 15.25 16.00 16.75 17.50 18.25 19.00 19.75 20.50 21.25 22.00 22.75 23.50 24.25 25.00 25.75 26.50 27.25 28.00 28.75 29.50 30.25 31.00 31.75 32.50 33.25 34.00 34.75 35.50 36.25 37.00 37.75 38.50 39.25 40.00 40.75 41.50 42.25 43.00 43.75 44.50 45.25 46.00 46.75 47.50 48.25 49.00 49.75 50.50 51.25 52.00 52.75 53.50 54.25 55.00 55.75 56.50 57.25 58.00 58.75 59.50 CMTR UTS CMTR FS CMTR YS Flow strength (FS) taken as average of YS and UTS adjusted from CMTR values using ASME Code temperature dependence for YS and UTS for SA182 Grade F316L or Grade F316, as appropriate.
Project Review Meeting: Advanced FEA Crack Growth Evaluations 94 May 8, 2007, North Bethesda, Maryland Work Status Validation Planning Validation planning is in progress, including consideration of application of the following:
- MRP-107 laboratory study for Alloy 182 pressure capsules
- Duane Arnold circumferential crack
- Ringhals 3 reactor vessel outlet nozzle axial flaws left in service
- Tsuruga 2 pressurizer safety and relief nozzle axial through-wall flaw associated with OD weld repairs
- VC Summer reactor vessel outlet nozzle leaking flaw, primarily in axial direction For other PWR experience with possible PWSCC in Alloy 82/182 piping butt welds, destructive examinations have not been performed
Project Review Meeting: Advanced FEA Crack Growth Evaluations 95 May 8, 2007, North Bethesda, Maryland Validation Planning MRP-107 Lab Study of PWSCC in Alloy 182 The report summary for MRP-107 (EPRI 1009399, 2004) includes the following:
- Abstract: Detailed examinations of Alloy 182 capsule samples containing PWSCC established the relationship between crack initiation sites and the microstructure of the weld metal. These examinations also identified microstructural features that facilitate or arrest PWSCC propagation. Crack initiation only occurred at high angle, high energy, dendrite packet grain boundaries, and growth apparently arrested at low energy boundaries due to low angular misorientation or coincidence of lattice sites. The work also revealed important findings with regard to crack geometries, in particular what aspect ratios may develop during PWSCC of nickel-base (Ni-base) weld metals.
- The cracks exhibited an unusual aspect ratio in that they never showed a large lateral surface extent, even when they extended through the wall thickness. This is a very different feature compared to PWSCC in Ni-base alloys such as Alloy 600. The aspect ratio is thought to relate to indications of crack arrest observed at low energy grain boundaries in Alloy 182.
Project Review Meeting: Advanced FEA Crack Growth Evaluations 96 May 8, 2007, North Bethesda, Maryland Validation Planning Duane Arnold Circumferential Crack The Duane Arnold crack is being considered as a potential comparison case
From MRP-113: Crack initiation and growth were attributed to the presence of a fully circumferential crevice that led to development of an acidic environment because of the oxygen in the normal BWR water chemistry, combined with high residual and applied stresses as a result of the geometry and nearby welds. The water chemistry conditions that contributed to cracking at Duane Arnold do not exist for the case of Alloy 82/182 butt welds in PWR plants.
Project Review Meeting: Advanced FEA Crack Growth Evaluations 97 May 8, 2007, North Bethesda, Maryland Validation Planning BWR Piping Experience with Circ Cracks (MRP-113)
Arc Length and Depth for Circumferential Cracks in BWR Plants (Some Points Represent Multiple Cracks) 20%
40%
60%
80%
100%
120%
0 30 60 90 120 150 180 210 240 270 300 330 360 Crack Length (deg)
Crack Depth (% Thru Wall) 14 in. Nozzles 12 in. Nozzles 10 in. Nozzles Duane Arnold Circ Flaw
Project Review Meeting: Advanced FEA Crack Growth Evaluations 98 May 8, 2007, North Bethesda, Maryland Validation Planning Ringhals 3 Reactor Vessel Outlet Nozzle Alloy 82/182 Weld 1.E-12 1.E-11 1.E-10 1.E-09 1.E-08 0
10 20 30 40 50 60 70 80 Stress Intensity Factor, K (MPam)
Crack Growth Rate, da /dt (m/s)
MRP-115 Curve for Alloy 182/132 MRP-115 Curve for Alloy 82 MRP-55 Curve for Alloy 600 Ringhals 3 / Crack 1 / Depth Increase from 2000 to 2001 Ringhals 3 / Crack 2 / Depth Increase from 2000 to 2001 1 mm/yr MRP-115 Curve for Alloy 182/132 CGR = 1.5x10-12K 1.6 MRP-115 Curve for Alloy 82 CGR = (1.5x10-12/2.6)K 1.6 All curves adjusted to 325°C using an activation energy of 130 kJ/mole (31.0 kcal/mole)
The points for the Ringhals 3 hot leg safe end weld cracks are based on the depth measurements made in 2000 and 2001 and the stress intensity factors calculated by Ringhals (points shown at average of initial and final K corresponding to best estimate initial and final depths). The Ringhals data were adjusted from the operating temperature of 319°C (606°F) to the reference temperature of 325°C (617°F) using the activation energy of 130 kJ/mole (31.0 kcal/mole).
Project Review Meeting: Advanced FEA Crack Growth Evaluations 99 May 8, 2007, North Bethesda, Maryland WRS Mockups EPRI/SI Preemptive Weld Overlay (PWOL) Mockup EPRI and Structural Integrity Associates (SI) have recently completed a project that included fabrication of a mockup of a general vessel nozzle configuration
- Attached to 10NPS pipe The next 10 slides include the surface stress measurements made on the PWOL mockup before the weld overlay was applied This information may be useful as part of the validation studies
Project Review Meeting: Advanced FEA Crack Growth Evaluations 100 May 8, 2007, North Bethesda, Maryland WRS Mockups EPRI/SI Preemptive Weld Overlay (PWOL) Mockup Drawing
Project Review Meeting: Advanced FEA Crack Growth Evaluations 101 May 8, 2007, North Bethesda, Maryland EPRI/SI PWOL Mockup Finite Element Model
Project Review Meeting: Advanced FEA Crack Growth Evaluations 102 May 8, 2007, North Bethesda, Maryland EPRI/SI PWOL Mockup Analysis Results Axial Residual Stresses Pre-PWOL Post-PWOL
Project Review Meeting: Advanced FEA Crack Growth Evaluations 103 May 8, 2007, North Bethesda, Maryland EPRI/SI PWOL Mockup Analysis Results Hoop Residual Stresses Pre-PWOL Post-PWOL
Project Review Meeting: Advanced FEA Crack Growth Evaluations 104 May 8, 2007, North Bethesda, Maryland EPRI/SI PWOL Mockup Residual Stress Measurements 3.820 6.320 6.820 ID Weld Repair SS CS 6.320 2.5 5.9 5.5 5.1
@ 45 and 135-dgrees 2.9 Surface measurements on ID and OD prior to Overlay Weld OD @ weld centerline, center of butter, and one additional location.4-in. from weld butter.
Project Review Meeting: Advanced FEA Crack Growth Evaluations 105 May 8, 2007, North Bethesda, Maryland EPRI/SI PWOL Mockup ID with 90° Weld Repair & XRD Measurement Locations 0° 45° 90° 135° ID Weld Repair
Project Review Meeting: Advanced FEA Crack Growth Evaluations 106 May 8, 2007, North Bethesda, Maryland EPRI/SI PWOL Mockup Axial Residual Stress Results: Pre-Overlay 0° 45° 90° 135° ID Weld Repair ID Surface Axial Stress Pre-Overlay Analysis vs. Measurements
-100
-80
-60
-40
-20 0
20 40 60 80 100 0
0.5 1
1.5 2
Dist. from DMW Centerline (in)
(towards nozzle)
Stresses (ksi)
Analysis XRD 45 XRD 0 XRD 90 A-182 Thru-wall Butter Region on ID SS Clad on ID A-182 Clad on ID
Project Review Meeting: Advanced FEA Crack Growth Evaluations 107 May 8, 2007, North Bethesda, Maryland EPRI/SI PWOL Mockup Axial Residual Stress Results: Post-Overlay 0° 45° 90° 135° ID Weld Repair ID Surface Axial Stress Post-Overlay Analysis vs. Measurements
-100
-80
-60
-40
-20 0
20 40 60 80 100 0
0.5 1
1.5 2
Dist. from DMW Centerline (in)
(towards nozzle)
Stresses (ksi)
Analysis XRD 45 XRD 135 Hole Drill A-182 Thru-wall Butter Region on ID SS Clad on ID A-182 Clad on ID
Project Review Meeting: Advanced FEA Crack Growth Evaluations 108 May 8, 2007, North Bethesda, Maryland EPRI/SI PWOL Mockup Hoop Residual Stress Results: Pre-Overlay 0° 45° 90° 135° ID Weld Repair ID Surface Hoop Stress Pre-Overlay Analysis vs. Measurements
-100
-80
-60
-40
-20 0
20 40 60 80 100 0
0.5 1
1.5 2
Dist. from DMW Centerline (in)
(towards nozzle)
Stresses (ksi)
Analysis XRD 45 XED 0 XRD 90 A-182 Thru-wall Butter Region on ID SS Clad on ID A-182 Clad on ID
Project Review Meeting: Advanced FEA Crack Growth Evaluations 109 May 8, 2007, North Bethesda, Maryland EPRI/SI PWOL Mockup Hoop Residual Stress Results: Post-Overlay 0° 45° 90° 135° ID Weld Repair ID Surface Hoop Stress Post-Overlay Analysis vs. Measurements
-100
-80
-60
-40
-20 0
20 40 60 80 100 0
0.5 1
1.5 2
Dist. from DMW Centerline (in)
(towards nozzle)
Stresses (ksi)
Analysis XRD 45 XRD 135 Hole Drill A-182 Thru-wall Butter Region on ID SS Clad on ID A-182 Clad on ID
Project Review Meeting: Advanced FEA Crack Growth Evaluations 110 May 8, 2007, North Bethesda, Maryland Benchmarking/Verification of SIF Calculation Approach Benchmarking and verification tasks are in progress to verify that the FEACrack/ANSYS software including new modules is producing mathematically correct answers Surface and through-wall crack test cases are being compared against published solutions
- Newman-Raju published solutions
- EPRI Ductile Fracture Handbook (Zahoor) solutions
- WRC Bulletin 471 (Anderson, et al.)
partial-arc semi-elliptical flaws uniform-depth axisymmetric flaw and loading
- Anderson solution for through-wall cracks in cylinders
- Cases performed by NRC contractor (EMC2) for selected custom crack profiles
- Other published solutions as available DEI is also performing general commercial software dedication of the FEACrack software per EPRI guidance
Project Review Meeting: Advanced FEA Crack Growth Evaluations 111 May 8, 2007, North Bethesda, Maryland Benchmarking/Verification of SIF Calculation Past Example 1: TW Circ Flaw in Cylinder Axially loaded through-wall flaw circumferential in cylinder SIF for model compared with EPRI Ductile Fracture Handbook results
- R/t = 10, max arc = 180° Results agree within 10%
Crack Face Crack Front Key Hole Symmetry Boundary Condition Crack Face Symmetry Boundary Conditions 26.5 ksiin 24.0 ksiin 180° 13.6 ksiin 12.7 ksiin 130° 7.1 ksiin 6.6 ksiin 80° 2.9 ksiin 2.9 ksiin 30° K Calculated per FEA Model Test Case KI Calculated Using Zahoor1 Crack Length 26.5 ksiin 24.0 ksiin 180° 13.6 ksiin 12.7 ksiin 130° 7.1 ksiin 6.6 ksiin 80° 2.9 ksiin 2.9 ksiin 30° K Calculated per FEA Model Test Case KI Calculated Using Zahoor1 Crack Length
Project Review Meeting: Advanced FEA Crack Growth Evaluations 112 May 8, 2007, North Bethesda, Maryland Benchmarking/Verification of SIF Calculation Past Example 2: Angled Crack in a Plate Model test performed to examine J-integral results with combined crack opening modes (I and II)
- Flaw 45° from horizontal Model dimensions selected such that KI = KII = 6.3 ksiin Combined J-integral = 2.62 in-lbs/in2 FEA results for average J-integral on crack front = 2.66 in-lbs/in2
Project Review Meeting: Advanced FEA Crack Growth Evaluations 113 May 8, 2007, North Bethesda, Maryland Benchmarking/Verification of SIF Calculation Past Example 3: Corner Crack on Plate Face Applied crack face pressure of 50 ksi Rooke and Cartwright peak SIF = 72.2 ksiin FEA results = 69.6 ksiin
Project Review Meeting: Advanced FEA Crack Growth Evaluations 114 May 8, 2007, North Bethesda, Maryland Benchmarking/Verification of SIF Calculation Verification and Validation Cases in Draft Phase I Calc Table 1. Inside Diameter Scaled up to Ri/t = 3 for Direct Comparison to Anderson Correlation Based on NRC Assumed WRS Distribution (with Scaled up Loading Resulting in Comparable Axial Stress Distribution)
No.
crack Ri/t a/t 2c/a 2 (deg)
Ksurf Kdeep Ksurf Kdeep Ksurf Kdeep V1 semi-elliptical 3
0.2 16 61.1 19.8 19.5 28.7 21.1 8.9 1.6 V2 semi-elliptical 3
0.4 16 122.2 24.0 6.7 31.9 9.0 7.8 2.3 V3 semi-elliptical 3
0.6 16 183.3 25.5 10.3 30.8 12.5 5.4 2.1 V4 semi-elliptical 3
0.8 16 244.5 25.0 29.6 27.9 29.9 2.9 0.3 Anderson (ksi-in0.5)
DEI FEA (ksi-in0.5)
Deviation Table 2. Inside Diameter Scaled up to Ri/t = 3 for Direct Comparison to Anderson Correlation Based on Actual FEA WRS Distribution Attained (with Scaled up Loading Resulting in Comparable Axial Stress Distribution)
No.
crack Ri/t a/t 2c/a 2 (deg)
Ksurf Kdeep Ksurf Kdeep Ksurf Kdeep V1 semi-elliptical 3
0.2 16 61.1 18.6 18.9 28.7 21.1 10.1 2.2 V2 semi-elliptical 3
0.4 16 122.2 22.6 6.9 31.9 9.0 9.3 2.1 V3 semi-elliptical 3
0.6 16 183.3 23.8 9.5 30.8 12.5 7.0 3.0 V4 semi-elliptical 3
0.8 16 244.5 23.3 26.5 27.9 29.9 4.6 3.4 DEI FEA (ksi-in0.5)
Deviation Anderson (ksi-in0.5)
Table 3. Selected FEA Cases for Case of No WRS Loading for Comparison to Anderson Correlation Extrapolated Down to Ri/t = 2.004 No.
crack Ri/t a/t 2c/a 2 (deg)
Ksurf Kdeep Ksurf Kdeep Ksurf Kdeep 3
semi-elliptical 2.004 0.1 15 42.9 2.6 6.2 2.9 6.4 0.4 0.2 15 semi-elliptical 2.004 0.3 5
42.9 7.2 9.9 7.8 10.1 0.6 0.2 18 semi-elliptical 2.004 0.3 21 180.1 2.4 12.2 2.3 12.1
-0.1
-0.1 20 semi-elliptical 2.004 0.3 30 257.3 1.5 13.0 0.6 12.2
-0.9
-0.8 DEI FEA (ksi-in0.5)
Deviation Anderson (ksi-in0.5)
Project Review Meeting: Advanced FEA Crack Growth Evaluations 115 May 8, 2007, North Bethesda, Maryland Leak Rate Calculations Approach PICEP and SQUIRT software models are being applied using crack morphology parameters appropriate to intergranular nature of PWSCC
- Wilkowski presentation at 2003 NRC Conference on Alloy 600 PWSCC in Gaithersburg, Maryland As a scoping tool, PICEP is being applied to calculate COD and leak rate as a function of assumed piping load
- See example on next slide For each FEA crack growth progression case, the leak rate as a function of time will be calculated on the basis of the COD directly from the through-wall portion of the complex crack FEA model
- The COD dependence through the wall thickness in the through-wall crack region will be examined to determine the controlling COD parameters
Project Review Meeting: Advanced FEA Crack Growth Evaluations 116 May 8, 2007, North Bethesda, Maryland 0.001 0.010 0.100 1.000 10.000 100.000 0
20 40 60 80 100 120 140 160 180 200 Total Crack Arc Length (deg)
Leak Rate (gpm at 70°F)
Full Moment (275 in-kips)
Half Moment Quarter Moment Zero Moment Leak Rate Calculations Example Scoping Results for WC Relief Nozzle DM Weld PRELIMINARY
Project Review Meeting: Advanced FEA Crack Growth Evaluations 117 May 8, 2007, North Bethesda, Maryland Plans for Next Meeting(s)
Previously tentatively scheduled meetings:
- May 29 telecon: Telcon on Phase II progress
- June 19 meeting: Present Phase II results
Project Review Meeting: Advanced FEA Crack Growth Evaluations 118 May 8, 2007, North Bethesda, Maryland Meeting Summary and Conclusions Industry NRC