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. #310Reston, VA 20190703.437.1155 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 Advanc ed 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 Ho tel and Conference Center North Bethesda, Maryland Project Review Meeting:Advanced FEA Crack Growth Evaluations 2May 8, 2007, North Bethesda, Maryland TopicsIntroductions -Industry and NRCStatus of Industry work, including response to April 4, 2007 NRC letter -IndustryStatus of NRC Confirmatory Research -NRCPresentation & Discussion of Proposed Matrix -IndustryAdditional 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 -IndustryPlans for next meeting(s) -Industry and NRCMeeting Summary and Conclusions -Industry and NRC Project Review Meeting:Advanced FEA Crack Growth Evaluations 3May 8, 2007, North Bethesda, Maryland Principal Meeting ParticipantsEPRI Project Management / Support
-Craig Harrington, EPRI
-Tim Gilman, Structural Integrity AssociatesProject Team
-Glenn White, DEI
-John Broussard, DEI
-Jean Collin, DEI
-Greg Thorwald, Quest Reliability, LLCExpert Review Panel
-Ted Anderson, Quest Reliability, LLC
-Warren Bamford, Westinghouse
-Doug Killian, AREVA
-Pete Riccardella, Structural Integrity Associates
-Ken Yoon, AREVANRC 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 4May 8, 2007, North Bethesda, Maryland Project Plan Phase II CalculationsPerform detailed sensitivity studies, benchmarking, and validation work specific to the pressurizer nozzle DM welds in the 9 spring 2008plants to evaluate the viability of leak before break for these welds
-Collection of geometry, loading, and we ld 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 sensitiv ity 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 likeli hood that the Wolf Creek indications were really growing as rapidly as assumed in the White Paper and NRC calculations
-Final report with methodology, resu lts, and validation in EPRI format Project Review Meeting:Advanced FEA Crack Growth Evaluations 5May 8, 2007, North Bethesda, Maryland Project Plan Additional Calculations with Crack Inserted into WRS ModelPerform 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 simulatedvia 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 so lutions, including those considering the standard ASME welding residual stress assumptions Project Review Meeting:Advanced FEA Crack Growth Evaluations 6May 8, 2007, North Bethesda, Maryland Work Status SummaryAssessment of plant-specific input s for 51 welds in 9 spring 2008 plants
-Dimensions
-Piping loads
-Available weld repair informationCritical 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 cr ack profile (part-depth and through-wall)
-Assessment of EPFM failure modeCrack 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 axisymme tric solution as scoping tool Project Review Meeting:Advanced FEA Crack Growth Evaluations 7May 8, 2007, North Bethesda, Maryland Work Status Summary (cont'd)Leak rate calculations
-PICEP and SQUIRT models
-Calculation of COD and leak ra te using PICEP as scoping tool
-Calculation of leak rate with COD from complex crack growth FEA calculationsDevelopment of matrix of WRS profiles
-Axisymmetric (self balance at every circumferential position)
-Non-axisymmetric (self balance over entire cross section)Development of analysis case matrixSoftware verification and benchmarkingValidation planning Project Review Meeting:Advanced FEA Crack Growth Evaluations 8May 8, 2007, North Bethesda, Maryland Work Status Software DevelopmentThe status of the new FEACrack software modules by Quest Reliability, LLC is as follows:
-Growth of surface crack with custom pr ofile (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 grow th for custom crack front profile for through-wall crack (<360°on ID & 360°on ID):
In progress
-New nozzle-to-safe-end geometry to facilita te placing crack into FEA WRS model:
May timeframeSee 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 DevelopedCustom surface crackAnsys macro text, input temperature gradientCustom 360 o crackNode redistribution, fatigue analysis Future DevelopmentComplex custom crackUpdate custom through-wall crackNozzle to safe end geometry Custom Surface CrackEnter all crack front node coordinatesAny number of nodes, arbitrary spacingAll nodes updated during fatigue analysis Custom 360 o CrackEnter all crack front node coordinates*Any number of nodes, arbitrary spacing*All nodes updated during fatigue analysis Node RedistributionAn option for fatigue analysis*helps avoid numerical problems at the crack tipNodes shift downward along the crack frontRelocate nodes on updated crack front to preserve the relative node spacing Complex Custom CrackThrough-wall crack shape at the OD crack tipCrack front curves to a part-depth crack along pipe IDUse custom crack coordinates for all crack front nodesQuarter symmetric model Custom Through-Wall Crack Thumbnail Profile Slanted ProfileCustom through-wall crack is availableTest 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 Attachme nt 1 (White Paper).
Nozzle-to-safe-end geometryAdd to FEACrack geometry libraryAutomatically create the crack mesh in the nozzle geometryAllow automated parametric analysis Project Review Meeting:Advanced FEA Crack Growth Evaluations 9May 8, 2007, North Bethesda, Maryland April 4, 2007, NRC Letter Comments on Crack Growth CalculationComment #1.The industry incremented the crack growth in the analyses basedon constant increment of crack growth in the leng th direction for the majority of the analyses.
This constraint caused the times for the cra ck extension at the surface and depth to be different. Even though these differences are smal l, 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 th e crack along the crack front by a constant time increment seems more logical and more representative of thecrack growth physical characteristics. We suggest further investigat ion into the crack increment calculation is warranted.Response.As discussed with the NRC on the April 9 conference call, thiscomment represents a misunderstanding of the crack increment calculationmethod. A standard fully explicit time stepping procedure is app lied. In order to investigate the adequacy of the time step size in the Ph ase I calculation, an improved estimate of the elapsed time was calculated based on the crack growth rate s 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 10May 8, 2007, North Bethesda, Maryland April 4, 2007, NRC Letter Comments on Crack Growth CalculationComment #2.
In Figure 11 of industry's Phase I calcul ations on the evolution of the stress intensity factors, a discontinuity occurred af ter the second increment of crack growth, and appears to occur at the same st ress intensity for each of the remaining steps. Industry's response to a question on this observati on during the March 20, 2007, teleconference was unclear, but industry indicated they be lieved the response was real. We suggest further investigation into the mesh densit y 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. Reduc ing the crack increment along the ID circumference results in a fully behaved stress intensity factorprofile. The new results for the Phase I calculation inputs confirm that this issue in fa ct had a small effect on the crack profile at the point of through-wall penetration.
Project Review Meeting:Advanced FEA Crack Growth Evaluations 11May 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 A pplied 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 12May 8, 2007, North Bethesda, Maryland Refined Phase I Calc Results Methodology AdjustmentsMesh refinement changes to shift additional nodes at surface region of crack frontTemperature loading adjustments and mesh refinement changes to improve through-wall stress distributionCrack shape study to develop more "natural"crack shape for initial size parametersReduced 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 conservative ly eliminated instantaneously as partial-arc crack approaches 360° Project Review Meeting:Advanced FEA Crack Growth Evaluations 13May 8, 2007, North Bethesda, Maryland Refined Phase I Calc Results Figure 2: WRS Distribution Assumption Based on ASME Data-30-20
-10 0 10 20 30 40 50 60 7000.10.20.30.40.50.60.70.80.91Normalized Distance from ID Surface, (r-ri)/tAxial Welding Residual Stress (ksi)DesiredCrack Depth180 SideTemperature profile improved to match desired curve PRELIMINARY Project Review Meeting:Advanced FEA Crack Growth Evaluations 14May 8, 2007, North Bethesda, Maryland Refined Phase I Calc Results Figure 3: Assumed Axial Stress Loading for Crack GrowthIdentical load case assumed as previous
-Endcap pressure load
-Dead weight force and moment
-Pipe thermal expansion force
and moment
-Assumed WRS distributionCrack face pressure also applied-30-20
-10 0 10 20 30 40 50 600.000.100.200.300.400.500.600.700.800.901.00Normalized Distance from ID Surface, (r-ri)/tAxial 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 15May 8, 2007, North Bethesda, Maryland Refined Phase I Calc Results Figure 4: Axial Extent of Impos ed Thermal Stress Simulating WRS-10,000 010,00020,00030,00040,00050,00060,00070,0000.000.501.001.502.002.503.00Axial Distance (in)Axial Stress (psi)Original ModelCrack Side Stress DistributionOpposite Crack Side Stress Distribution PRELIMINARY Project Review Meeting:Advanced FEA Crack Growth Evaluations 16May 8, 2007, North Bethesda, Maryland 00.050.10.150.20.250.30.350.400.511.522.533.54Circumferential Distance Along ID (in)Crack Depth (in)Initial Flaw for "Grown" Case"Grown" Flaw ShapePure 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 17May 8, 2007, North Bethesda, Maryland 05,00010,00015,00020,00025,000 30,00035,00040,0000.00.10.20.30.40.50.60.70.80.91.0Relative 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 ShapePure Semi-Ellipse Flaw Shape Refined Phase I Calc Results Methodology Adjustments (cont'd)Additional refinement and "natural"shape yield smoother crack tip SIF profile PRELIMINARY Project Review Meeting:Advanced FEA Crack Growth Evaluations 18May 8, 2007, North Bethesda, Maryland Refined Phase I Calc Results Figure 7: Growth Progression in Flat Plane 0.000.20 0.400.600.801.00 1.200.01.02.03.04.05.06.07.08.0Circumferential Distance Along ID (in)Crack Depth (in)2c/a=20.9, a/t=0.2602c/a=18.9, a/t=0.3102c/a=18.4, a/t=0.3422c/a=18.5, a/t=0.3752c/a=19.0, a/t=0.3952c/a=19.5, a/t=0.4132c/a=20.0, a/t=0.4282c/a=20.5, a/t=0.4392c/a=21.3, a/t=0.4542c/a=21.9, a/t=0.4662c/a=22.6, a/t=0.4812c/a=23.1, a/t=0.4932c/a=ID circ, a/t=0.4932c/a=ID circ, a/t=0.5482c/a=ID circ, a/t=0.6262c/a=ID circ, a/t=0.7032c/a=ID circ, a/t=0.7812c/a=ID circ, a/t=0.8582c/a=ID circ, a/t=0.9362c/a=ID circ, a/t=1.000Selected growth steps shown PRELIMINARY Project Review Meeting:Advanced FEA Crack Growth Evaluations 19May 8, 2007, North Bethesda, Maryland Refined Phase I Calc Results Profile Comparison vs. Draft Phase 1 Result PRELIMINARY0.000.200.400.600.801.001.200.01.02.03.04.05.06.07.08.0Circumferential Distance Along ID (in)Crack Depth (in)Original Model Final ShapeCurrent Model Final Shape Project Review Meeting:Advanced FEA Crack Growth Evaluations 20May 8, 2007, North Bethesda, Maryland0.00.10.20.30.40.50.60.70.80.91.0012345678time (yr)a/t - Full Momenta/t - Half MomentFraction Cracked - Full Moment Refined Phase I Calc Results Figure 9: Crack Depth and Area Development PRELIMINARY Project Review Meeting:Advanced FEA Crack Growth Evaluations 21May 8, 2007, North Bethesda, Maryland 05,00010,00015,00020,00025,00030,00035,00040,000 0.0 0.1 0.20.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0Relative Distance Along Crack Front from Deepest Point to Surface Point (--)FEA Stress Intensity Factor, K (psi-in0.5)2c/a=20.9, a/t=0.2602c/a=18.9, a/t=0.3102c/a=18.4, a/t=0.3422c/a=18.5, a/t=0.3752c/a=19.0, a/t=0.3952c/a=19.5, a/t=0.4132c/a=20.0, a/t=0.4282c/a=20.5, a/t=0.4392c/a=21.3, a/t=0.4542c/a=21.9, a/t=0.4662c/a=22.6, a/t=0.4812c/a=23.1, a/t=0.4932c/a=ID circ, a/t=0.4932c/a=ID circ, a/t=0.5482c/a=ID circ, a/t=0.6262c/a=ID circ, a/t=0.7032c/a=ID circ, a/t=0.7812c/a=ID circ, a/t=0.8582c/a=ID circ, a/t=0.936 Refined Phase I Calc Results Figure 11: SIF Along Crack Front PRELIMINARYSelected growth steps shown Project Review Meeting:Advanced FEA Crack Growth Evaluations 22May 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 40,0000.00.10.20.30.40.50.60.70.80.91.0Maximum Crack Depth, a/tCrack-Tip Stress Intensity Factor, K (psi-in 0.5)K at Deepest PointK at Surface PointK at Joined Edge PRELIMINARY Project Review Meeting:Advanced FEA Crack Growth Evaluations 23May 8, 2007, North Bethesda, Maryland Refined Phase I Calc ResultsFigure 14: Crack Stability -Supportable Moment 0 500 1,000 1,500 2,000 2,500 3,0000.00.10.20.30.40.50.60.70.80.91.0a/tMax Supportable Moment (in-kips)Entire Crack in TensionCrack Takes CompressionCrack Does Not Take CompressionApplied Moment PRELIMINARYSupportable 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 24May 8, 2007, North Bethesda, Maryland Refined Phase I Calc Results SummaryThrough-wall flaw reached after approximately 7.5 years
-Increase in growth time due to refi ned time step and other refinementsNet section collapse moment for final flaw shape is 1300 in-kips vs. 275 in-kips load (4.7 greater)-Based on conservative case in which crack face does not take compression Project Review Meeting:Advanced FEA Crack Growth Evaluations 25May 8, 2007, North Bethesda, Maryland April 4, 2007, NRC Letter Comments on Crack Growth CalculationComment #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 dr iven 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 cr ack 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 ca lculation 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 isexpected 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 t he statement regarding the likelihood of critical 360°surface cracks, recent work indicates that the surface crack islikely to arrest or greatly slow in growth without reaching cr itical crack size given lower bending moments and similar residual stresses (see following slides).
Project Review Meeting:Advanced FEA Crack Growth Evaluations 26May 8, 2007, North Bethesda, Maryland Crack Growth with Zero MomentAxisymmetric Results for WC Relief Nozzle with 360°FlawAssumed axisymmetric stress profile at rightEndcap pressure based on ID at DM weldDead weight axial force includedNormal thermal axial force includedWRS profile of Phase 1 calculation also assumed-30-20
-10 0 10 20 30 40 50 600.000.100.200.300.400.500.600.700.800.901.00Normalized Distance from ID Surface, x/tAxial Stress with Residual Stress (ksi)EndCap Press + DW + T + WRSPRELIMINARY Project Review Meeting:Advanced FEA Crack Growth Evaluations 27May 8, 2007, North Bethesda, Maryland Crack Growth with Zero MomentAxisymmetric Results for WC Relief Nozzle with 360°FlawSIF per WRC Bulletin solution for fully axisymmetric stress field (cubic dependence on
radial coordinate) and 360°uniform depth circumferential surface
crackWRC Bulletin includes influence coefficients for
case of R i/t= 2, so no extrapolation neededCrack face pressure applied via superposition-30-20-10 0 10 20 30 40 500.000.100.200.300.400.500.600.700.800.901.00Normalized Crack Depth, a/tStress Intensity Factor with Residual Stress (ksi-in0.5)EndCap Press + CrackFaceP + DW + T + WRSPRELIMINARY Project Review Meeting:Advanced FEA Crack Growth Evaluations 28May 8, 2007, North Bethesda, Maryland Crack Growth with Zero MomentAxisymmetric Results for WC Relief Nozzle with 360°FlawCrack depth vs. time based on integration of MRP-115 CGR equation at 650°FCrack arrest predicted at depth of about a/t= 0.35Conclusion 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 ratio0.00.10.20.30.40.5 0.60.70.80.91.002468101214161820Time (years)Normalized Crack Depth from ID Surface, a/tEndCap Press + CrackFaceP + DW + T + WRSPRELIMINARY Project Review Meeting:Advanced FEA Crack Growth Evaluations 29May 8, 2007, North Bethesda, MarylandCrack Growth with "Axisymmetric"MomentAxisymmetric Results for WC Relief Nozzle with 360°FlawAssumed axisymmetric stress profile at rightAxisymmetric linear stress profile Mr/I added to previous zero moment caseM taken as half base case moment of 275 in-kipsThis hypothetical axisymmetric case bounds
capability of moment to drive crack through-wall for assumed WRS profile-30-20
-10 0 10 20 30 40 50 600.000.100.200.300.400.500.600.700.800.901.00Normalized Distance from ID Surface, x/tAxial Stress with Residual Stress (ksi)EndCap Press + DW + T + WRSPRELIMINARY Project Review Meeting:Advanced FEA Crack Growth Evaluations 30May 8, 2007, North Bethesda, MarylandCrack Growth with "Axisymmetric"MomentAxisymmetric Results for WC Relief Nozzle with 360°FlawSame SIF solution procedure as before using WRC BulletinCrack face pressure applied via superposition-30-20-10 0 10 20 30 40 500.000.100.200.300.400.500.600.700.800.901.00Normalized Crack Depth, a/tStress Intensity Factor with Residual Stress (ksi-in0.5)EndCap Press + CrackFaceP + DW + T + WRSPRELIMINARY Project Review Meeting:Advanced FEA Crack Growth Evaluations 31May 8, 2007, North Bethesda, MarylandCrack Growth with "Axisymmetric"MomentAxisymmetric Results for WC Relief Nozzle with 360°FlawCrack depth vs. time based on integration of MRP-115 CGR equation at 650°FCrack arrest predicted at depth of about a/t= 0.45Conclusion 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 ratio0.00.10.20.30.40.5 0.60.70.80.91.00102030405060Time (years)Normalized Crack Depth from ID Surface, a/tEndCap Press + CrackFaceP + DW + T + WRSPRELIMINARY Project Review Meeting:Advanced FEA Crack Growth Evaluations 32May 8, 2007, North Bethesda, Maryland0.000.200.400.600.801.001.200.01.02.03.04.05.06.07.08.0Circumferential Distance Along ID (in)Crack Depth (in)2c/a=20.9, a/t=0.2602c/a=19.8, a/t=0.3032c/a=20.0, a/t=0.3262c/a=20.7, a/t=0.3422c/a=21.5, a/t=0.3542c/a=22.5, a/t=0.3632c/a=23.5, a/t=0.3702c/a=24.6, a/t=0.3762c/a=25.7, a/t=0.3812c/a=26.8, a/t=0.3852c/a=27.9, a/t=0.3892c/a=29.1, a/t=0.3922c/a=ID circ, a/t=0.3922c/a=ID circ, a/t=0.3992c/a=ID circ, a/t=0.426 Crack Growth with Reduced Moment FEA Results for WC Relief Nozzle with 21:1 FlawGrowth progression in flat plane for case of half previously assumed piping moment PRELIMINARYSelected growth steps shown Project Review Meeting:Advanced FEA Crack Growth Evaluations 33May 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 1.0012345678time (yr)a/tFull MomentHalf Moment PRELIMINARYCrack depth development for case of ha lf previously assumed piping moment Project Review Meeting:Advanced FEA Crack Growth Evaluations 34May 8, 2007, North Bethesda, Maryland Crack Growth with Reduced Moment FEA Results for WC Relief Nozzle with 21:1 FlawSIF along crack front for case of half previously assumed pipingmoment 05,00010,00015,00020,000 25,00030,00035,000 40,000 0.00.10.2 0.30.4 0.5 0.60.7 0.8 0.91.0Relative Distance Along Crack Front from Surface Point to Deepest Point (--)FEA Stress Intensity Factor, K (psi-in0.5)2c/a=20.9, a/t=0.2602c/a=19.8, a/t=0.3032c/a=20.0, a/t=0.3262c/a=20.7, a/t=0.3422c/a=21.5, a/t=0.3542c/a=22.5, a/t=0.3632c/a=23.5, a/t=0.3702c/a=24.6, a/t=0.3762c/a=25.7, a/t=0.3812c/a=26.8, a/t=0.3852c/a=27.9, a/t=0.3892c/a=29.1, a/t=0.3922c/a=ID circ, a/t=0.3922c/a=ID circ, a/t=0.3992c/a=ID circ, a/t=0.426 PRELIMINARYSelected growth steps shown Project Review Meeting:Advanced FEA Crack Growth Evaluations 35May 8, 2007, North Bethesda, Maryland 0 5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,0000.00.10.20.30.40.50.60.70.80.91.0Maximum Crack Depth, a/tCrack-Tip Stress Intensity Factor, K (psi-in0.5)K at Deepest PointK at Surface PointK at Joined Edge Crack Growth with Reduced Moment FEA Results for WC Relief Nozzle with 21:1 FlawSIF at deepest and surface points vs. depth for case of half previously assumed piping moment PRELIMINARY Project Review Meeting:Advanced FEA Crack Growth Evaluations 36May 8, 2007, North Bethesda, Maryland Crack Growth with Full MomentFEA Results for WC Relief Nozzle with 360°FlawInitial and final flaw shape comparison for partial-arc initial flaw vs. 360°initial flaw0.000.20 0.400.600.801.001.200.01.02.03.04.05.06.07.08.0Circumferential Distance Along ID (in)Crack Depth (in)Start w/ PD 26% deep @ 21:1Start w/ ID 360 @ 10% deepPD Initial Flaw ShapeID Circ Initial Flaw Shape PRELIMINARY Project Review Meeting:Advanced FEA Crack Growth Evaluations 37May 8, 2007, North Bethesda, Maryland New FEA Crack Growth Cases ConclusionsSmooth 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 profilesGreater time step refinement (with other minor changes) yields time to through-wall of about 7.5 yearsReduced moment leads to flaw arrest for assumed through-wall stress distributionHigh 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 y ears to reach same final flaw shape Project Review Meeting:Advanced FEA Crack Growth Evaluations 38May 8, 2007, North Bethesda, Maryland April 4, 2007, NRC Letter Comments on Critical Crack Size CalculationComment #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 di splacement-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 staff's view that in conduc ting critical crack size analyses, industrymust address the following concerns.-Comment #4a.The location of the crack in a dissi milar 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 s lightly 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 assumptionis to use the lower safe-end strength properties. This fact is su pported by both analyses and experiments.
Project Review Meeting:Advanced FEA Crack Growth Evaluations 39May 8, 2007, North Bethesda, Maryland April 4, 2007, NRC Letter Comments on Critical Crack Size Calculation (cont'd)
-Comment #4b.
Elastic-plastic fracture mechanics should be considered since in the NRC analyses, this condition controlled for so me crack geometries. For an idealized circumferential through-wall crack as used in industry's failure analysis, the NRC staff's detailed finite element elastic-plastic analyses an d pipe tests showed that failure stress would be below that predicted by li mit-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 lo ad. This crack shape is similar to the flaw found in the Duane Arnold safe end. The resu lts also indicate that secondary stresses can lead to rapid severance of pipes containing complex cracks. Consequently, there can be significant non-conservatism in the industry's fracture analysis.
Project Review Meeting:Advanced FEA Crack Growth Evaluations 40May 8, 2007, North Bethesda, Maryland April 4, 2007, NRC Letter Comments on Critical Crack Size Calculation (cont'd)
-Comment #4c.
For large cracks, especially surface an d complex cracks, the plasticity is localized to the area surroundi ng the crack, and therefore th e 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 th ese secondary stresses will act as a primary stress. If the failure stresses are above yield of the uncracke d 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 t hese 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 designrules 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 ex pansion stress that illustrate this fracture behavior in NUREG reports and technical papers.
Project Review Meeting:Advanced FEA Crack Growth Evaluations 41May 8, 2007, North Bethesda, Maryland April 4, 2007, NRC Letter Industry Response to Comment #4Pete Riccardella of SI to present main response to Comment #4Additional 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 42May 8, 2007, North Bethesda, Maryland April 4, 2007, NRC Letter Ductile Tearing of Thin Surface LigamentsSection 2.2.1 and Figure 4 of the draft EM C2 technical basis document for critical crack size recommend that a factor be applied for deep surface cracksThere 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 liga ments 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 th e 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 43May 8, 2007, North Bethesda, Maryland April 4, 2007, NRC Letter Nominal Stress in Adjacent PipingThis plots shows nominal stress in the attached piping assuming
the same pressure, axial force, and effective moment Meff as reported for the nozzlesThe stress is shown relative to the Code yield strength based
on preliminary piping material
assumptionsThese results show yield level stresses in
-some safety/relief and spray nozzle cases
-all surge nozzle casesThe results may be relevant regarding the role of secondary
stress in the crack stability
calculations0.00.51.01.52.02.501 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)(P m+P b)/ y 00.1 0.20.30.4 0.5 0.6 0.70.80.9 10.00 0.75 1.502.2 53.00 3.75 4.50 5.2 56.0 06.757.50 8.259.0 09.7 5 1 0.50 1 1.25 1 2.00 12.7 513.5014.25 1 5.00 1 5.7 516.5 017.2 518.00 1 8.75 19.5 020.2 521.0 0 2 1.75 2 2.50 23.2 5 24.0 024.75 2 5.50 2 6.2 5 2 7.0 027.7 528.50 2 9.25 3 0.00 30.7 531.5 0 3 2.25 3 3.00 3 3.7534.5 035.25 3 6.00 3 6.75 37.5 038.2 5 3 9.00 3 9.75 4 0.50 41.2 542.00 4 2.75 4 3.50 4 4.2 545.0 045.7546.50 4 7.25 48.0 048.7 549.5 0 5 0.25 5 1.00 51.7 552.5053.25 5 4.00 5 4.7 555.5 056.2 557.00 5 7.75 58.5 0 59.2 560.0 0P+DW+TP+DW+T+TstratNotes1. P m = PD o/4t + Faxial/Ametalwhere Faxial = DW+T or DW+T+Tstrat axial forceand Ametal = (D o 2 - D i 2)/42. P b = Meff D o/2Iwhere I = (R o 4 - R i 4)/43. y = 18.5 ksi for S&R and spray piping based on Code min YS for A376 TP316 at 650°F4. 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 44May 8, 2007, North Bethesda, Maryland Status of NRC Confirmatory ResearchTo be presented by NRC Project Review Meeting:Advanced FEA Crack Growth Evaluations 45May 8, 2007, North Bethesda, Maryland Proposed Case Matrix ItemsItem 1.Plant Specific GeometriesItem 2.Plant Specific LoadsItem 3.Proposed Weld Residual Stresses
-Cracks growing in an axisymmetric WRS field
-Cracks growing in an axisymmetric + repair WRS fieldItem 4.Crack Growth Rate EquationItem 5. Multiple Crack Growth CalculationsOther Items
-Initial flaw geometry
-Redistribution of load given high WRS at ID surface
-Crack inserted directly into th e 3-dimensional DEI WRS FEA model Project Review Meeting:Advanced FEA Crack Growth Evaluations 46May 8, 2007, North Bethesda, Maryland Nozzle Geometry for Subject Plants SummaryThere 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 sa fe 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 (R i/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 47May 8, 2007, North Bethesda, Maryland Nozzle Geometry for Subject Plants Geometry CasesA 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 ext end 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 exte nding to DM weld), connected to 12 pipe Project Review Meeting:Advanced FEA Crack Growth Evaluations 48May 8, 2007, North Bethesda, Maryland Nozzle Geometry and Repair History PRELIMINARY Summary TableDesign #Piping NPSLiner?DM Weld t (in.)DM Weld R i/tWeld Sep. (in.)Butter WeldRepairsID Weld RepairsOD Weld RepairsDesign #Piping NPSLiner?DM Weld t (in.)DM Weld R i/tWeld Sep. (in.)Butter WeldRepairsID Weld RepairsOD Weld RepairsPlant A1a6"N1.292.02.2NRNRNR1a6"N1.292.02.2NRNRR4Plant E1a6"N1.292.02.2NRNRR1a6"N1.292.02.2NRNRNRPlant H1a6"N1.292.02.2NRNRNR1a6"N1.292.02.2NRRRPlant B2a6"Y1.072.62.6NRNRR12a6"Y1.072.62.6NRNRNRPlant G2a6"Y1.072.62.6NRNRNR2a6"Y1.072.62.6NRNRNRPlant C2b6"Y1.072.62.3NRNRNR2b6"Y1.072.62.3Plant F1b6"N1.411.83.3NRNRNR1b6"N1.411.83.3Plant D36"N1.411.86.8NRNRNR36"N1.411.86.8RNRNRPlant I36"N1.411.86.8N/AN/AN/A36"N1.411.86.8N/AN/AN/APlant J1a6"N1.292.02.2Rx5R1R11a6"N1.292.02.2RR2NRNotes: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.
- 3. For Designs #4, #5, and #6, sleeve covers but does not contact DM weld.4. For Design #8, sleeve directly covers DM weld.5. For Designs #7 and #9, sleeve does not extend to 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 available9. 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 APlantCodeRelief R R Project Review Meeting:Advanced FEA Crack Growth Evaluations 49May 8, 2007, North Bethesda, Maryland Nozzle Geometry and Repair History PRELIMINARY Summary Table (cont'd)Design #Piping NPS Liner?DM Weld t (in.)DM Weld R i/tWeld Sep. (in.)Butter WeldRepairsID Weld RepairsOD Weld RepairsDesign #Piping NPSLiner?DM Weld t (in.)DM Weld R i/tWeld Sep. (in.)Butter WeldRepairsID Weld RepairsOD Weld RepairsPlant A1a6"N1.292.02.2NRR1NR1a6"N1.292.02.2NRNRNRPlant E1a6"N1.292.02.2NRNRNR1a6"N1.292.02.2NRRNRPlant H1a6"N1.292.02.2NRNRNR1a6"N1.292.02.2NRNRNRPlant B2a6"Y1.072.62.6NRNRNR2a6"Y1.072.62.6NRNRNRPlant G2a6"Y1.072.62.6NRNRNR2a6"Y1.072.62.6NRNRNRPlant C2b6"Y1.072.62.32b6"Y1.072.62.3Plant F1b6"N1.411.83.3NRNRNR1b6"N1.411.83.3NRNRNRPlant D36"N1.411.86.8NRNRNR36"N1.411.86.8NRNRNRPlant I36"N1.411.86.8N/AN/AN/APlant J1a6"N1.292.02.2NRR6x2NR1a6"N1.292.02.2NRNRNRNotes: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.3. For Designs #4, #5, and #6, sleeve covers but does not contact DM weld.
- 6. NR = No weld repairs reported7. 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.PlantCodeSafety BSafety CNo Safety C RR Project Review Meeting:Advanced FEA Crack Growth Evaluations 50May 8, 2007, North Bethesda, Maryland Nozzle Geometry and Repair History PRELIMINARY Summary Table (cont'd)Design #Piping NPS Liner?DM Weld t (in.)DM Weld R i/tWeld Sep. (in.)Butter WeldRepairsID Weld RepairsOD Weld RepairsDesign #Piping NPSLiner?DM Weld t (in.)DM Weld R i/tWeld Sep. (in.)Butter WeldRepairsID Weld RepairsOD Weld RepairsPlant A44"Y0.902.2~2.3NRNRNR814"N1.583.83.4NRR5R3Plant E44"Y0.902.2~2.3RNRR814"N1.583.83.4NRR3NRPlant H814"N1.583.83.4NRNRNRPlant B54"Y0.782.72.2NRNRNR814"N1.583.83.4R1R1x2R2Plant G54"Y0.782.72.2NRNRNR814"N1.583.83.4NRNRNRPlant C54"Y0.782.7~2.2814"N1.563.83.5NRNRNRPlant F66"N1.152.53.6NRNRNRPlant D74"N1.061.43.3NRNRNR912"N1.473.43.0NRNRNRPlant I74"N1.061.43.3N/AN/AN/A912"N1.473.43.0N/AN/AN/APlant J44"Y0.902.2~2.3RNRNR814"N1.583.83.4R2R1NRNotes: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.3. For Designs #4, #5, and #6, sleeve covers but does not contact DM weld.
- 6. NR = No weld repairs reported7. 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.PlantCodeSpray (all have thermal sleeve)Surge (all have thermal sleeve)Already PDI examinedAlready structural overlayed R
Project Review Meeting:Advanced FEA Crack Growth Evaluations 51May 8, 2007, North Bethesda, Maryland Nozzle Geometry for Subject Plants Basic Weld Dimensions 0 2 4 6 8 10 12 1401 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 4000.000.751.502.25 3.0 03.754.505.256.00 6.7 57.508.259.009.7510.5011.25 12.0012.75 1 3.50 14.2515.0 0 15.7516.5 0 1 7.2518.0018.7 519.5020.2521.0021.75 22.5023.25 2 4.00 24.7525.5 0 26.2527.0 0 2 7.7528.5029.2 530.0030.7531.5 032.2533.0 033.7534.50 35.2536.00 36.7537.50 3 8.25 39.0039.7 5 4 0.5041.2542.0 042.7543.5 044.2545.00 45.7546.50 4 7.2548.00 4 8.75 49.5050.2 5 5 1.0051.7552.5 053.2554.0 054.7555.50 56.2557.00 5 7.7558.50 5 9.25 60.00ID (in)OD (in)t (in)ID/t Project Review Meeting:Advanced FEA Crack Growth Evaluations 52May 8, 2007, North Bethesda, Maryland Nozzle Geometry for Subject Plants As-Built Dimensional InformationAvailable as-built dimensions are being collected for the subject weldsThis 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 weldsSensitivity 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 53May 8, 2007, North Bethesda, Maryland As-Built Dimensional Information Review of Plant H As-Built DimensionsFollowing as-built dimensions are preliminarySafety/Relief
-LAS nozzle end thickness of 1.16-1.37vs. design of 1.42 (including cladding)
-Butter thickness of 0.80vs. design of 0.81Spray-LAS nozzle end thickness of 0.87-0.92vs. design of 1.00 (including liner) and 0.88 (without liner)
-Safe end OD at DM weld of ~5.65vs. design of 5.62Surge-LAS nozzle end thickness of 1.40-1.60vs. design of 1.51 (including cladding)
-Butter thickness of 0.30vs. design of 0.81In general, as-built thickness of butter buildup on LAS nozzle end can vary significantly Project Review Meeting:Advanced FEA Crack Growth Evaluations 54May 8, 2007, North Bethesda, Maryland As-Built Dimensional Information Review of Plant C As-Built DimensionsFollowing as-built dimensions are preliminary
-There is uncertainty in the weld separation figures because onlyaxial length of various materials on OD is providedRelief-Separation distance of ~2.18 vs. design of 2.32-DM weld circumference of 24.5vs. 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 ~2.2vs. design of 2.32Safety 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 ~2.3vs. 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 55May 8, 2007, North Bethesda, Maryland As-Built Dimensional Information Review of Plant C As-Built Dimensions (cont'd)Spray-Separation distance of ~3.25 vs. design of 2.2Surge-Separation distance of ~3.73 vs. design of 3.46-Average DM weld thickness of 1.501vs. 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 56May 8, 2007, North Bethesda, Maryland Plant-Specific Piping Loads ApproachDesign pipe loads have now been collected for each of the 51 subject weldsDifferences 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 sizeTherefore, cover full range of piping loads for 51 subject welds:
-All plants 2235 psig pressure
-Range of axial membrane stress loading, P m-Range of bending stress loading, P b-Range of ratio of bending to total stress loading, P b/(P m+P b)-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 57May 8, 2007, North Bethesda, Maryland Plant-Specific Piping Loads Nominal Axial Piping Loads (Not Including Endcap Pressure Load) 0 10 20 30 4001 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)00.10.20.30.40.50.60.70.80.9 1 0.0 00.751.502.253.003.754.505.256.006.757.508.259.00 9.7 5 10.50 1 1.25 12.00 1 2.75 13.5014.2515.0015.7516.5017.2518.0 018.7519.5 020.25 2 1.00 21.75 2 2.50 23.25 2 4.0024.75 25.5026.2527.0027.7528.5029.2530.0030.7 531.5 0 3 2.2533.0 0 3 3.75 34.50 3 5.2536.00 36.7537.50 38.2539.0039.7540.5041.2542.0042.7 5 4 3.5044.2 5 4 5.0045.7 5 4 6.5047.25 48.0048.75 49.5050.25 51.0051.7552.5053.2554.0 054.7555.5 0 5 6.2557.0 0 5 7.75 5 8.50 59.2560.00 DWDW+SSEDW+TDW+T+SSEDW+T+StratDW+T+Strat+SSE Project Review Meeting:Advanced FEA Crack Growth Evaluations 58May 8, 2007, North Bethesda, Maryland Plant-Specific Piping Loads Nominal Effective Bending Moment Load (Full Scale) 01000 2000 300040005000 600001 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) 00.10.20.30.40.50.60.70.80.9 10.00 0.7 51.502.253.003.754.505.256.00 6.7 57.508.259.009.75 10.50 1 1.2512.0 012.7513.5014.25 15.00 1 5.7516.5 017.2518.0018.75 19.50 2 0.2521.0 021.7522.50 23.25 2 4.0024.7 525.5 026.2527.00 27.75 2 8.5029.2 5 3 0.00 3 0.7531.5 032.2533.00 33.75 3 4.5035.2 536.0036.7537.50 38.25 3 9.0039.7 540.5041.2542.00 42.75 4 3.5044.2 545.0045.75 46.50 47.25 4 8.0048.7 549.5050.25 51.00 5 1.7552.5 053.2 554.0054.75 55.5056.25 57.00 5 7.75 5 8.5059.2 560.00P+DWP+DW+SSEP+DW+TP+DW+T+SSEP+DW+T+StratP+DW+T+Strat+SSE Project Review Meeting:Advanced FEA Crack Growth Evaluations 59May 8, 2007, North Bethesda, Maryland Plant-Specific Piping Loads Nominal Effective Bending Moment Load (Partial Scale) 0 100 200 300 400 500 600 700 80001 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) 00.10.20.30.40.50.60.70.80.9 10.00 0.7 51.502.253.003.754.505.256.006.757.508.25 9.0 09.75 1 0.5011.2 512.0012.7 513.5014.2515.0015.7516.50 17.25 1 8.00 18.75 19.50 2 0.2521.0 0 2 1.7522.5 023.2524.0024.7525.5026.25 27.0027.75 28.50 2 9.2530.00 30.75 3 1.5032.2 5 3 3.0033.7 534.5035.2536.0036.7537.50 38.2539.00 39.75 4 0.5041.2 5 42.00 4 2.7543.5 044.2545.0 045.7546.5047.2548.0048.75 49.50 5 0.25 51.00 5 1.7552.5 053.2 5 5 4.0054.7 555.5056.2557.0057.7558.50 59.2560.00P+DWP+DW+SSEP+DW+TP+DW+T+SSEP+DW+T+StratP+DW+T+Strat+SSE Project Review Meeting:Advanced FEA Crack Growth Evaluations 60May 8, 2007, North Bethesda, Maryland Plant-Specific Piping Loads ASME Code Nominal Stress Loading for Pressure and Dead Weight Loading 0 4 8 12 1601 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)
P m , P b , P m+P b Stress Loading (ksi) 00.10.20.30.40.50.60.70.80.9 10.00 0.751.502.2 5 3.003.7 5 4.5 0 5.256.0 0 6.7 5 7.50 8.2 5 9.00 9.75 1 0.50 1 1.2 5 1 2.0 012.75 1 3.5 0 1 4.2515.0 015.7 516.5017.2 5 1 8.0 018.7 5 1 9.5 0 2 0.2 5 2 1.0 0 2 1.7 5 2 2.5 0 2 3.2 5 2 4.0 0 2 4.7 5 2 5.50 2 6.2 5 2 7.0027.7528.5 029.2530.0 0 3 0.7 531.5 0 3 2.2 5 3 3.0 0 3 3.7 5 3 4.5 0 3 5.2 5 3 6.0 0 3 6.7 5 3 7.5 0 3 8.2539.00 3 9.7 540.5041.2 5 4 2.0042.7 543.5 044.2545.0 0 4 5.7 5 4 6.5 0 4 7.2 5 4 8.0 0 4 8.7 5 4 9.5 0 5 0.2 5 5 1.0 051.75 5 2.5 0 5 3.2554.0 0 5 4.7555.5056.2 5 5 7.0 057.7 5 5 8.5 0 5 9.2 560.0 0 PmPm with SSE PbPb with SSEPm+PbPm+Pb with SSE Project Review Meeting:Advanced FEA Crack Growth Evaluations 61May 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 2001 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)
P m , P b , P m+P b Stress Loading (ksi) 00.10.20.30.40.50.60.70.80.9 10.00 0.751.502.2 5 3.003.7 5 4.5 0 5.256.0 0 6.7 5 7.50 8.2 5 9.00 9.75 1 0.50 1 1.2 5 1 2.0 012.75 1 3.5 0 1 4.2515.0 015.7 516.5017.2 5 1 8.0 018.7 5 1 9.5 0 2 0.2 5 2 1.0 0 2 1.7 5 2 2.5 0 2 3.2 5 2 4.0 0 2 4.7 5 2 5.50 2 6.2 5 2 7.0027.7528.5 029.2530.0 0 3 0.7 531.5 0 3 2.2 5 3 3.0 0 3 3.7 5 3 4.5 0 3 5.2 5 3 6.0 0 3 6.7 5 3 7.5 0 3 8.2539.00 3 9.7 540.5041.2 5 4 2.0042.7 543.5 044.2545.0 0 4 5.7 5 4 6.5 0 4 7.2 5 4 8.0 0 4 8.7 5 4 9.5 0 5 0.2 5 5 1.0 051.75 5 2.5 0 5 3.2554.0 0 5 4.7555.5056.2 5 5 7.0 057.7 5 5 8.5 0 5 9.2 560.0 0 PmPm with SSE PbPb with SSEPm+PbPm+Pb with SSE Project Review Meeting:Advanced FEA Crack Growth Evaluations 62May 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 4001 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)
P m , P b , P m+P b Stress Loading (ksi) 00.1 0.20.30.4 0.5 0.6 0.70.80.9 10.000.751.502.253.003.754.505.256.006.757.508.259.009.7510.5 011.2512.0012.7 513.5014.2515.0015.7 516.5017.25 18.0018.7519.5020.2521.0 021.7522.50 23.2524.0024.7525.5026.2 527.0027.75 28.5029.2530.0030.7531.5032.2533.00 33.7534.5035.25 36.0036.7537.5038.25 39.0039.7540.50 41.2542.0042.7543.50 44.2545.0045.75 46.50 4 7.2548.0048.75 49.5050.2551.00 51.75 5 2.5053.2554.00 54.7555.5056.25 57.00 5 7.7558.5059.25 60.00 PmPm with SSE PbPb with SSEPm+PbPm+Pb with SSE Project Review Meeting:Advanced FEA Crack Growth Evaluations 63May 8, 2007, North Bethesda, Maryland Plant-Specific Piping Loads Treatment of Loads in Crack Growth ModelingEach category of loading be treated as follows in the crack growth calculation:
-Deadweight: Axial force and bendin g 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 fo r 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 mo ment (surge nozzle only): Added to normal thermal loads
-Thermal stratification pipe bending moment fo r plant transients (surge nozzle only): Not relevant for crack growth
-Welding residual stress: Multiple case s assumed as described separately below
-Local thermal stress due to differential ther mal 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 64May 8, 2007, North Bethesda, Maryland Plant-Specific Piping Loads Treatment of Loads in Crack Growth Modeling (cont'd)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 stressThis is a simplification as torsion would act as a Mode II and/or III loading on the crack 2 22 3 2effyz MMMT Project Review Meeting:Advanced FEA Crack Growth Evaluations 65May 8, 2007, North Bethesda, Maryland Proposed Case Matrix Welding Residual StressSummary of May 1 MeetingFabrication Steps affecting WRS
-Last Pass Fill-In Weld (Surge)
-Fillet Welds (Safety/Relief)
-Buildup on Safe End IDRepairs-Deep ID Repairs
-ID Repairs on Spray Nozzle?
Project Review Meeting:Advanced FEA Crack Growth Evaluations 66May 8, 2007, North Bethesda, Maryland Welding Residual Stress Agenda of May 1 Meeting at DEI OfficesNozzle and weld geometry cases for subject weldsCollected weld repair information for subject weldsApplication 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 fo r selected subject weld casesWRS data for piping butt welds in open literatureCandidate WRS profiles
-Axisymmetric profiles
-Non-axisymmetric profilesValidation of WRS inputsMeeting wrap-up Project Review Meeting:Advanced FEA Crack Growth Evaluations 67May 8, 2007, North Bethesda, Maryland Proposed Case Matrix Tentative New FEA WRS Cases Planned at May 1 MeetingEffect of SS weld on stress in DM weld
-One axisymmetric case to be selected ba sed on design and available as-built weld separation data
-Influence is expected to depend on x/t and R i/t , where x is the weld separation distanceSurge 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 weldSpray nozzle cases
-Consider deferring until Plant C an d F weld repair records are searchedSafety/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 68May 8, 2007, North Bethesda, Maryland Development of WRS Cases ApproachBecause of the uncertainty in the true re sidual stress field in each of the 51 subject welds, a matrix of sensit ivity cases will be considered covering a wide range of WRS patternsRange 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 i nput to selection of WR S profiles for analysisAs previously planned, the follow ing 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 fo r 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 mo ckups and removed components Project Review Meeting:Advanced FEA Crack Growth Evaluations 69May 8, 2007, North Bethesda, Maryland Development of WRS Cases Approach (cont'd)Patterns of WRS variability will be considered in both the radial and circumferential directionsFor the cylindrical shell SIF model, the WRS will be simulated using an applied thermal input pattern, whic h 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 theeffect of residual stress relaxationFor selected sensitivity cases of the optional SIF modeling, the3-dimensional WRS field from the DE I intact WRS FEA model will be directly input to the cracked SIF model Project Review Meeting:Advanced FEA Crack Growth Evaluations 70May 8, 2007, North Bethesda, Maryland Welding Residual Stress Inputs Weld Fabrication and Repair Data Compiled for Wolf CreekAvailable 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 71May 8, 2007, North Bethesda, Maryland Nozzle Geometry and Repair History PRELIMINARY Weld Repair Summary TableTableLinePlantCodeNozzleTypeNozzleCountDesign#Butteringor WeldLength(in.)Depth(in.)Length(in.)Depth(in.)Length(in.)Depth(in.)Length(in.)Depth(in.)Length(in.)Depth(in.)Length(in.)Depth(in.)1ASafety A11aweldODN/AN/A4N/A~1/2N/A~1/2N/A~1/2N/A~1/22ASafety B21aweldIDN/AN/A11/25/83ERelief31aweldODN/ANN/AN/AN/A 4ESafety C41aweldID<22%N/ANN/AN/AN/A5ID82YN/AN/AN/A6OD82YN/AN/AN/A7FSafety A61bNRNRNRNRNRNRNR8BRelief72aweldOD182N/A10.50.375 9CSafety A82bNRNRNRNRNRNRNR10CSafety B92bNRNRNRNRNRNRNR11CSafety C102bNRNRNRNRNRNRNR12DSafety A113butterN/AN/AYN/AN/AN/A13butterID82YN/AN/A~0.314weldODN/ANN/AN/AN/A15CSpray135NRNRNRNRNRNRNR 16IDN/AN/A51.55/163.750.523/162.55/1625/1617ODN/AN/A32.50.520.513/1618ESurge158weldID<10%82N3N/AN/AN/AN/AN/AN/A19butterN/A82Y1N/AN/A20OD182N/A21.750.8751.51 21ID182N/A11.00.62522ID182N/A140.75Notes: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.
- 3. For Designs #4, #5, and #6, sleeve covers but does not contact DM weld.4. For Design #8, sleeve directly covers DM weld.5. NR = Information not yet reported (or may not be available)6. N/A = Information not available7. Weld repair entries for Plants C and F are preliminary.PWHTafterRepair?Alloy82 or182# Defect orRepairAreasDefect/RepairArea #6Defect/RepairArea #4Defect/RepairArea #5Defect/RepairArea #1Defect/RepairArea #2Defect/RepairArea #3Safety AH1aweld 5ESpray4ASurge8 12weldweldBSurge8 14 16ID/OD (%circ.)
Project Review Meeting:Advanced FEA Crack Growth Evaluations 72May 8, 2007, North Bethesda, Maryland Nozzle Geometry and Repair History PRELIMINARY Weld Repair Summary Table (cont'd)TableLinePlantCodeNozzleTypeNozzleCountDesign#Butteringor WeldLength(in.)Depth(in.)Length(in.)Depth(in.)Length(in.)Depth(in.)Length(in.)Depth(in.)Length(in.)Depth(in.)Length(in.)Depth(in.)WC1N/A82/182YN/AN/AN/AWC2ID+OD82Y21/27/16ID 17/16ODWC3OD182Y113/4 WC4ID82Y33/43/42-1/43/41/23/4WC5OD182Y313/42-1/43/41/23/4WC6OD82N/A11-1/41/2WC7ID82N/A11/21/2WC8butterN/A182YN/AN/A1/8WC9weldID82N/A21-1/411/327/811/32WC1082N/A62-1/23/411/21-1/21/211/22-1/23/42-1/23/4WC1182N/A61-1/21/21-1/413/47/81-1/23/811-1/161/21/2 WC12JSprayWC44butterlip/bondline82YN/AN/AN/AWC13butterOD182Y27/89/161-1/81WC14weldID82Y117/16Notes: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.3. For Designs #4, #5, and #6, sleeve covers but does not contact DM weld.4. For Design #8, sleeve directly covers DM weld.5. NR = Information not yet reported (or may not be available)
- 6. N/A = Information not available7. Weld repair entries for Plants C and F are preliminary.PWHTafterRepair?Alloy82 or182# Defect orRepairAreasDefect/RepairArea #6Defect/RepairArea #4Defect/RepairArea #5Defect/RepairArea #1Defect/RepairArea #2Defect/RepairArea #3weldJRelief1aWC1 1aJSurge8WC2WC5ID/OD (%circ.)JSafety BWC31aweldIDbutterJSafety A Project Review Meeting:Advanced FEA Crack Growth Evaluations 73May 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 contributorto butt weld PWSCC The generic welding residual stress model is conservative for the as-designed case without repairsWeld repairs from the ID surface (360°or partial-arc) significantly increase ID surface stresses
-Generic welding residual stress model does not bound FEA resultsfor cases involving repairs from the ID surfaceDeep partial-arc weld repairs from the OD surf ace have high restraint and may produce similar through-wall stress dist ributions as for cases of ID repairs depending on depth of repair
-Generic welding residual stress model does not bound FEA resultsfor some cases involving partial-arc repairs from the OD surfaceHigh stresses for cases involving partial-ar c repairs are limited to the repaired area
-Expected to produce cracks limite d to the repaired area, not 360° Project Review Meeting:Advanced FEA Crack Growth Evaluations 74May 8, 2007, North Bethesda, MarylandPiping Butt Weld WRS -Literature Review Preliminary ConclusionsPiping Butt Welds Without Repairs:
-Stress measurements show that welding star t/stops can produce variations in axial and hoop stress on the order of or greater t han 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 tensileaxial residual stress-Location of maximum axial tensile stresse s can be in the repair zone or possibly opposite the repair zone depending on the location of the repairrelative 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 gr eater increases in axial tensile residual stresses Project Review Meeting:Advanced FEA Crack Growth Evaluations 75May 8, 2007, North Bethesda, Maryland Validation of WRS Inputs ApproachA 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 meta l applications and other informationVarious 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 76May 8, 2007, North Bethesda, Maryland Validation of WRS Inputs Approach (cont'd)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 77May 8, 2007, North Bethesda, Maryland Proposed Case Matrix Crack Growth Rate EquationSensitivity 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 ti me 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 ve rsus Alloy 182 passes (factor of 2.6)
-Lower CGR for growth perpendicular to dendrit e solidification direction (factor of 2.0)No credit being taken for a SIF threshold Project Review Meeting:Advanced FEA Crack Growth Evaluations 78May 8, 2007, North Bethesda, Maryland MRP-115 Crack Growth Rate Equation Screened MRP Lab CGR Database for Alloys 82/182/132Average CGR data for Alloys 182/132 after screening (43 points)Average CGR data for Alloy 82 after screening (34 points)1.E-121.E-111.E-101.E-091.E-080102030405060708 0Stress Intensity Factor, K (MPam)Crack Growth Rate, da/dt (m/s)1mm/yrMRP-55 Curvefor Alloy 600MRP-21 Curvefor Alloy 182All CGRs are adjusted to account for percentage engagement across the crack front but not alloy type or crack orientation1.E-121.E-111.E-101.E-09 1.E-080102030405060708 0Stress Intensity Factor, K (MPam)Crack Growth Rate, da/dt (m/s)1mm/yrMRP-55 Curvefor Alloy 600MRP-21 Curve for Alloy 182All 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 79May 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 1.00.11.10.Weld Factor, fweldCumulative Distribution F9 182 Welds8 82 Welds2 132 WeldsLog-Normal FitWeld factors for 19 welds of Alloy 82/182/132material with fit log-normal distribution(most likely estimator), K th = 0, and best fit 25th Percentile75th PercentileMedianThe Alloy 82 data have been normalized (increased) by applying a factor of 2.61:
1/falloy = 2.61 The variability in "weld factor"from the statis tical evaluations of laboratory CGR data in MRP-115 will be used to investigate the effect of uncertainty in thepower-law constant Project Review Meeting:Advanced FEA Crack Growth Evaluations 80May 8, 2007, North Bethesda, Maryland MRP-115 Crack Growth Rate Equation Recommended Disposition Curves (325°C)1.E-121.E-111.E-101.E-09 1.E-0801020304050607080Stress 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/yrMRP-115 Curve for Alloy 182/132CGR = 1.5x10-12 K1.6MRP-115 Curve for Alloy 82CGR = (1.5x10-12/2.6)K1.6For 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 MetalLaboratory 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 81May 8, 2007, North Bethesda, Maryland Proposed Case Matrix Effect of Multiple CracksAs 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 IDSensitivity cases will investigate the effect of multiple crack initiationSeveral potential approaches are being considered:
-Enveloping of multiple initia l 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 fl aws to investigate influence of each flaw on the other as a function of th eir separation on the weld IDSee 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 K I at nearest crack tips Crack Tip Interaction Fig. 2.58 Interaction of two identical coplanar through-wall cracks in an infinite plate; K I magnified at crack tip B Parallel Cracks Fig. 2.59 Parallel cracks; shielding causes decrease in K I
Parallel Crack Shielding Fig. 2.60 Interaction between two identical parallel through-wall cracks in an infinite plate; crack tip shielding
decreases K I compared to a single crack Crack Interaction ModelsUse a single crack and a symmetry plane near the crack tip to get K interactionInclude multiple cracks in a modelUser-defined geometry method from FEACrack*Same or different crack shapes*Adjust distance between crack fronts Project Review Meeting:Advanced FEA Crack Growth Evaluations 82May 8, 2007, North Bethesda, Maryland Proposed Case Matrix Other Items: Initial Flaw GeometrySensitivity 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 83May 8, 2007, North Bethesda, Maryland Proposed Case Matrix Other Items: Effect of Elastic-Plastic Redistribution of LoadCases to investigate effect of elastic-plastic redistribution of load given high WRS at ID surface
-The applied WRS profile may be modified to in vestigate this effect as implied in the following figure: 20
-10 0 10 20 30 40 50 600.000.100.200.300.400.500.600.700.800.901.00Normalized Distance from ID Surface, (r-ri)/tAxial 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 84May 8, 2007, North Bethesda, Maryland Proposed Case Matrix Other Items: Crack Inserted into WRS FEA ModelIt 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 85May 8, 2007, North Bethesda, Maryland Proposed Case Matrix Other Items: Crack Inserted into WRS FEA ModelThis type of approach was applied in a preliminary fashion by DEI in 2005 for a reactor pressure vessel outlet nozzleThe FEACrack enhancement for this wo rk will reduce the effort required to insert the crack mesh into t he 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 RatioIntact Axial Operating StressesAxial Stress Redistribution with Circ Crack Project Review Meeting:Advanced FEA Crack Growth Evaluations 86May 8, 2007, North Bethesda, MarylandAdditional Topics -Industry and NRCCritical Crack Size Calculations
-IndustryValidation studies and WRS mockups
-IndustryBenchmarking NRC/Industry K Solutions for the Advanced FEA Calculations
-Industry-NRCLeak-rate Calculations
-Industry Project Review Meeting:Advanced FEA Crack Growth Evaluations 87May 8, 2007, North Bethesda, Maryland Calculating Critical Crack Size ApproachScoping 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 forthe 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-factorThe flow strength in the net secti on collapse calculations will be based on the safe end material, given the potential for the crack to be located
close to the safe endCrack stability for each calculated crack growth progression (surface crack and through-wall) is bei ng checked using a spreadsheet implementation of the NSC solution published by Rahman and Wilkowski for an arbitrary crack prof ile, assuming thin-wall equilibrium Project Review Meeting:Advanced FEA Crack Growth Evaluations 88May 8, 2007, North Bethesda, Maryland Calculating Critical Crack Size Approach (cont'd)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 dire ction is not assumed to be lined up with the symmetry (i.e., center) point on the crackConsider secondary stresses as appropriate
-See separate presentation by Pete Riccardella of SIApply 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 SIAs described above, the crack growth progression is also checkedfor the potential effect of local ligament collapse
-For complex crack profile at point leakage becomes detectable
-For complete growth progression to exam ine potential effect on the progression Project Review Meeting:Advanced FEA Crack Growth Evaluations 89May 8, 2007, North Bethesda, Maryland Calculating Critical Crack Size Defining Pipe Loads for Critical Crack SizeEach 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: Treatm ent 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 presentat ion slides by Pete Riccardella of SI
-Thermal stratification pipe bending moment for plant transients (surge nozzle only): Treatment of secondary stresses discussed in presentation slidesby 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 90May 8, 2007, North Bethesda, Maryland Calculating Critical Crack Size Force and Moment Equilibrium for Arbitrary CrackRahman and Wilkowski have published the thin-wall solution for axial force and applied moment equilibrium given a circumferential flaw with arbitrary depth profileDEI has implemented this solution in spreadsheet formThe 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 compressionArbitrary Net Section Collapse (ANSC)
software by Structural Integrity Associates
used to validate spreadsheet calculation
-ANSC also allows arbitrar y moment direction, unlike Rahman and WilkowskiS. Rahman and G. Wilkowski, "Net-Section-Collapse Analysis of Circumferentially Cracked Cylinders-Part I: Arbitrar y-Shaped Cracks and Generalized Equations,"Engineering Fracture Mechanics, Vol. 61, pp. 191-211, 1998.
Project Review Meeting:Advanced FEA Crack Growth Evaluations 91May 8, 2007, North Bethesda, Maryland Calculating Critical Crack Size Safe End Flow StrengthBecause any hypothetical SCC could be located close to the safe end material, the safe end flow strengt h will be applied in the limit load crack stability calculationsDesign 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 casesThe following two slides show application of CMTR data to determine
likely range of flow strength at temp erature for the subject safe ends
-Flow strength taken as average of yield and ultimate strength
-Assumed temperature dependenc e between room temperat ure and 650°F based on Code temperature dependences for these materials: S 650°F= CMTR (Code 650°F/Code RT)The results of this investigation s upport the use of the 45.6 ksi flow strength value assumed in the NRC ca lculations for the WC safe end Project Review Meeting:Advanced FEA Crack Growth Evaluations 92May 8, 2007, North Bethesda, Maryland Calculating Critical Crack Size CMTR Strength Values for Safe Ends 0 10 20 30 40 50 60 70 8001 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) 00.1 0.20.30.4 0.5 0.60.70.80.9 10.000.50 1.001.502.00 2.503.004.755.255.756.256.757.25 7.758.258.75 9.259.7510.2511.0011.5012.0012.5013.00 13.7514.2514.7515.2515.75 16.2516.7517.25 17.7518.2518.75 19.2519.7520.2520.7521.25 21.7522.2522.75 23.2523.7524.25 24.7525.2525.7526.2526.75 27.2527.7528.25 28.7529.2529.7530.2530.75 31.2531.7532.25 32.7533.2533.75 34.2534.7535.2535.7536.25 36.7537.2537.75 38.2538.7539.2539.7540.25 40.7541.2541.75 42.2542.7543.25 43.7544.2544.7545.2545.75 46.2546.7547.25 47.7548.2548.7549.2549.75 50.2550.7551.2551.7552.2552.75 53.2553.7554.2554.7555.25 55.7556.2556.7557.2557.7558.25 58.7559.2559.75CMTR UTSCMTR FSCMTR YSFlow strength (FS) taken as average of YS and UTS listed in safe end CMTR.
Project Review Meeting:Advanced FEA Crack Growth Evaluations 93May 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 8001 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 00.10.20.30.40.5 0.60.70.80.9 10.0 00.7 51.5 02.2 53.0 05.0 05.7 56.5 07.2 5 8.0 08.7 59.5 010.25 1 1.25 1 2.0012.7513.75 1 4.50 1 5.2516.0016.75 1 7.50 1 8.2519.0019.7 5 2 0.50 2 1.2522.0022.7 523.5 0 2 4.2525.0 025.7 526.50 2 7.2528.0 028.7 529.5030.2531.0 031.7 532.5033.2534.0034.7 535.5036.2537.00 37.7538.5039.2540.00 40.75 4 1.5042.2543.00 4 3.75 4 4.5045.2546.00 4 6.75 4 7.5048.2549.0 0 4 9.75 5 0.5051.2552.0 052.7 5 5 3.5054.2555.0 055.7 5 5 6.5057.2 558.0 058.7 559.50CMTR UTSCMTR FSCMTR YSFlow 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 94May 8, 2007, North Bethesda, Maryland Work Status Validation PlanningValidation 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 directionFor 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 95May 8, 2007, North Bethesda, Maryland Validation Planning MRP-107 Lab Study of PWSCC in Alloy 182The report summary for MRP-107 (EPRI 1009399, 2004) includes the following:
-"Abstract: Detailed examinations of Al loy 182 capsule samples containing PWSCC established the relationship between crack in itiation sites and the microstructure of the weld metal. These examinations also identified microstructural features that facilitate or arrest PWSCC propagation. Cr ack 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 fi ndings 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 ra tio in that they never showed a large lateral surface extent, even when they extended through the wallthickness. 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 arrestobserved at low energy grain boundaries in Alloy 182."
Project Review Meeting:Advanced FEA Crack Growth Evaluations 96May 8, 2007, North Bethesda, Maryland Validation Planning Duane Arnold Circumferential CrackThe Duane Arnold crack is being considered as a potential comparison caseFrom MRP-113:Crack initiation and growth were attributedto the presence of a fully circumferential crevice that led to development of an acidic environment because of the oxygenin the normal BWR water chemistry, combined with highresidual and applied stresses as a result of the geometry andnearby welds. The water chemistr y conditions th at contributedto cracking at Duane Arnold do not exist for the case of Alloy82/182 butt welds in PWR plants.
Project Review Meeting:Advanced FEA Crack Growth Evaluations 97May 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%0306090120150180210240270300330360Crack Length (deg)Crack Depth (% Thru Wall)14 in. Nozzles12 in. Nozzles10 in. Nozzles Duane Arnold Circ Flaw Project Review Meeting:Advanced FEA Crack Growth Evaluations 98May 8, 2007, North Bethesda, Maryland Validation Planning Ringhals 3 Reactor Vessel Outlet Nozzle Alloy 82/182 Weld1.E-121.E-111.E-10 1.E-09 1.E-0801020304050607080Stress Intensity Factor, K (MPam)Crack Growth Rate, da/dt (m/s)MRP-115 Curve for Alloy 182/132MRP-115 Curve for Alloy 82MRP-55 Curve for Alloy 600Ringhals 3 / Crack 1 / DepthIncrease from 2000 to 2001Ringhals 3 / Crack 2 / DepthIncrease from 2000 to 20011 mm/yrMRP-115 Curve for Alloy 182/132CGR = 1.5x10-12 K1.6MRP-115 Curve for Alloy 82CGR = (1.5x10-12/2.6)K1.6All curves adjusted to 325°Cusing 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 99May 8, 2007, North Bethesda, Maryland WRS Mockups EPRI/SI Preemptive Weld Overlay (PWOL) MockupEPRI and Structural Integrity Associates (SI) have recently completed a project that included fabrication of a mockup of a general vessel nozzle configuration
-Attached to 10 NPS pipeThe next 10 slides include the surface stress measurements made on the PWOL mockup before the weld overlay was appliedThis information may be useful as part of the validation studies Project Review Meeting:Advanced FEA Crack Growth Evaluations 100May 8, 2007, North Bethesda, Maryland WRS Mockups EPRI/SI Preemptive Weld Overlay (PWOL) Mockup Drawing Project Review Meeting:Advanced FEA Crack Growth Evaluations 101May 8, 2007, North Bethesda, Maryland EPRI/SI PWOL Mockup Finite Element Model Project Review Meeting:Advanced FEA Crack Growth Evaluations 102May 8, 2007, North Bethesda, Maryland EPRI/SI PWOL Mockup Analysis Results Axial Residual StressesPre-PWOLPost-PWOL Project Review Meeting:Advanced FEA Crack Growth Evaluations 103May 8, 2007, North Bethesda, Maryland EPRI/SI PWOL Mockup Analysis Results Hoop Residual StressesPre-PWOLPost-PWOL Project Review Meeting:Advanced FEA Crack Growth Evaluations 104May 8, 2007, North Bethesda, Maryland EPRI/SI PWOL Mockup Residual Stress Measurements 3.8206.3206.820ID Weld Repair SS CS6.3202.5 5.9 5.55.1@ 45 and 135-dgrees2.9Surface measurements on ID and OD prior to Overlay WeldOD @ weld centerline, center of butter, and one additional location .4-in. from weld butter.
Project Review Meeting:Advanced FEA Crack Growth Evaluations 105May 8, 2007, North Bethesda, Maryland EPRI/SI PWOL MockupID with 90°Weld Repair & XRD Measurement Locations 0°45°90°135°ID Weld Repair Project Review Meeting:Advanced FEA Crack Growth Evaluations 106May 8, 2007, North Bethesda, Maryland EPRI/SI PWOL Mockup Axial Residual Stress Results: Pre-Overlay 0°45°90°135°ID Weld RepairID Surface Axial StressPre-Overlay Analysis vs. Measurements-100-80-60-40
-20 0 20 40 60 80 10000.511.52Dist. from DMW Centerline (in)(towards nozzle)Stresses (ksi) AnalysisXRD 45XRD 0XRD 90 A-182 Thru-wall Butter Region on IDSS Clad on ID A-182 Clad on ID Project Review Meeting:Advanced FEA Crack Growth Evaluations 107May 8, 2007, North Bethesda, Maryland EPRI/SI PWOL Mockup Axial Residual Stress Results: Post-Overlay 0°45°90°135°ID Weld RepairID Surface Axial StressPost-Overlay Analysis vs. Measurements-100-80-60-40-20 0 20 40 60 80 10000.511.52Dist. from DMW Centerline (in)(towards nozzle)Stresses (ksi) AnalysisXRD 45XRD 135Hole Drill A-182 Thru-wall Butter Region on IDSS Clad on ID A-182 Clad on ID Project Review Meeting:Advanced FEA Crack Growth Evaluations 108May 8, 2007, North Bethesda, Maryland EPRI/SI PWOL Mockup Hoop Residual Stress Results: Pre-Overlay 0°45°90°135°ID Weld RepairID Surface Hoop StressPre-Overlay Analysis vs. Measurements-100-80-60
-40
-20 0 20 40 60 8010000.511.52Dist. from DMW Centerline (in)(towards nozzle)Stresses (ksi) Analysis XRD 45XED 0 XRD 90 A-182 Thru-wall Butter Region on IDSS Clad on ID A-182 Clad on ID Project Review Meeting:Advanced FEA Crack Growth Evaluations 109May 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 StressPost-Overlay Analysis vs. Measurements-100-80-60-40-20 0 20 40 60 8010000.511.52Dist. from DMW Centerline (in)(towards nozzle)Stresses (ksi) AnalysisXRD 45XRD 135Hole Drill A-182 Thru-wall Butter Region on IDSS Clad on ID A-182 Clad on ID Project Review Meeting:Advanced FEA Crack Growth Evaluations 110May 8, 2007, North Bethesda, Maryland Benchmarking/Verification of SIF Calculation ApproachBenchmarking and verification tasks are in progress to verify that the FEACrack/ANSYS software including new modules is producing mathematically correct answersSurface 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 availableDEI is also performing general commercial software dedication ofthe FEACrack software per EPRI guidance Project Review Meeting:Advanced FEA Crack Growth Evaluations 111May 8, 2007, North Bethesda, Maryland Benchmarking/Verification of SIF Calculation Past Example 1: TW Circ Flaw in CylinderAxially loaded through-wall flaw circumferential in cylinderSIF for model compared with EPRI Ductile Fracture
Handbook results
-R/t = 10, max arc = 180°Results agree within 10%Crack FaceCrack Front Key HoleSymmetry BoundaryConditionCrack FaceSymmetry Boundary Conditions 26.5 ksiin24.0 ksiin 180 13.6 ksiin12.7 ksiin 1307.1 ksiin 6.6 ksiin 802.9 ksiin 2.9 ksiin 30 KCalculated perFEA Model Test Case K ICalculated UsingZahoor 1Crack Length 26.5 ksiin24.0 ksiin 180 13.6 ksiin12.7 ksiin 1307.1 ksiin 6.6 ksiin 802.9 ksiin 2.9 ksiin 30 KCalculated perFEA Model Test Case K ICalculated UsingZahoor 1Crack Length Project Review Meeting:Advanced FEA Crack Growth Evaluations 112May 8, 2007, North Bethesda, Maryland Benchmarking/Verification of SIF Calculation Past Example 2: Angled Crack in a PlateModel test performed to examine J-integral results with combined crack opening
modes (I and II)
-Flaw 45°from horizontalModel dimensions selected such that K I= K II= 6.3 ksiinCombined J-integral = 2.62 in-lbs/in 2FEA results for average J-integral on crack front = 2.66
in-lbs/in 2 Project Review Meeting:Advanced FEA Crack Growth Evaluations 113May 8, 2007, North Bethesda, Maryland Benchmarking/Verification of SIF Calculation Past Example 3: Corner Crack on Plate FaceApplied crack face pressure of 50 ksiRooke and Cartwright peak SIF = 72.2 ksiinFEA results = 69.6 ksiin Project Review Meeting:Advanced FEA Crack Growth Evaluations 114May 8, 2007, North Bethesda, Maryland Benchmarking/Verification of SIF Calculation Verification and Validation Cases in Draft Phase I CalcTable 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.crackRi/ta/t2c/a 2(deg)Ksur fKdeepKsurfKdeepKsurfKdeepV1semi-elliptical30.21661.119.819.528.721.18.91.6V2semi-elliptical30.416122.224.06.731.99.07.82.3 V3semi-elliptical30.616183.325.510.330.812.55.42.1 V4semi-elliptical30.816244.525.029.627.929.92.90.3Anderson (ksi-in0.5)DEI FEA (ksi-in0.5)DeviationTable 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.crackRi/ta/t2c/a 2(deg)Ksur fKdeepKsurfKdeepKsurfKdeepV1semi-elliptical30.21661.118.618.928.721.110.12.2V2semi-elliptical30.416122.222.66.931.99.09.32.1 V3semi-elliptical30.616183.323.89.530.812.57.03.0 V4semi-elliptical30.816244.523.326.527.929.94.63.4DEI FEA (ksi-in0.5)DeviationAnderson (ksi-in0.5)Table 3. Selected FEA Cases for Case of No WR S Loading for Comparison to Anderson Correlation Extrapolated Down to Ri/t = 2.004No.crackRi/ta/t2c/a 2 (deg)KsurfKdeepKsurfKdeepKsurfKdeep3semi-elliptical2.0040.11542.92.66.22.96.40.40.215semi-elliptical2.0040.3542.97.29.97.810.10.60.218semi-elliptical2.0040.321180.12.412.22.312.1-0.1-0.1 20semi-elliptical2.0040.330257.31.513.00.612.2-0.9-0.8DEI FEA (ksi-in0.5)Deviation Anderson (ksi-in0.5)
Project Review Meeting:Advanced FEA Crack Growth Evaluations 115May 8, 2007, North Bethesda, Maryland Leak Rate Calculations ApproachPICEP 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 PWSCCin Gaithersburg, MarylandAs a scoping tool, PICEP is being applied to calculate COD and leak rate as a function of assumed piping load
-See example on next slideFor 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 determ ine the controlling COD parameters Project Review Meeting:Advanced FEA Crack Growth Evaluations 116May 8, 2007, North Bethesda, Maryland0.0010.010 0.1001.00010.000100.000020406080100120140160180200Total Crack Arc Length (deg)Leak Rate (gpm at 70°F)Full Moment (275 in-kips)Half MomentQuarter MomentZero Moment Leak Rate Calculations Example Scoping Results for WC Relief Nozzle DM Weld PRELIMINARY Project Review Meeting:Advanced FEA Crack Growth Evaluations 117May 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 118May 8, 2007, North Bethesda, Maryland Meeting Summary and ConclusionsIndustryNRC