ML14149A402

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Calculation 32-9219662-000, Weld Residual Stress Analysis for PVNGS3 Rv Bmi Nozzle Repair, (Non-Proprietary), Attachment 3
ML14149A402
Person / Time
Site: Palo Verde Arizona Public Service icon.png
Issue date: 04/18/2014
From: Riordan T
AREVA
To:
Office of Nuclear Reactor Regulation
Shared Package
ML14149A349 List:
References
102-06879-JJC-JHK-DCE 32-9219662-000
Download: ML14149A402 (42)
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Enclosure Relief Request 52 Proposed Alternative in Accordance with 10 CFR 50.55a(a)(3)(i)

ATTACHMENT 3 Weld Residual Stress Analysis for PVNGS Unit 3 RV BMI Nozzle Repair

0402-01-FOl (Rev. 018, 01/30/2014)

A CALCULATION

SUMMARY

SHEET (CSS)

AREVA Document No. 32 - 9219662 - 000 Safety Related: ZYes 0 No Title Weld Residual Stress Analysis for PVNGS3 RV BMI Nozzle Repair (Non-Proprietary)

PURPOSE AND

SUMMARY

OF RESULTS:

AREVA Inc. proprietary information in the document is indicated by pairs of braces "[H".

PURPOSE:

Visual inspection of the reactor vessel Bottom Mounted Instrument (BMI) nozzles at Palo Verde Nuclear Generation Station, Unit 3 (PVNGS3), in October of 2013 revealed the presence of boric acid crystals on the outside of the lower head at BMI nozzle #3. Boric acid deposits at the gap between the nozzle and head indicate leakage of primary water through cracks in the J-Groove weld and the nozzle wall. AREVA performed a half nozzle repair of nozzle #3 that maintained the full incore instrumentation functionality of the nozzle. This repair, described in References [1] and [2], moves the primary pressure boundary nozzle weld from the inside of the vessel to a weld pad on the outside surface.

The purpose of this report is to document the weld residual stress (WRS) finite element analysis of the as-left J-Groove weld for use in subsequent fracture mechanics analysis.

SUMMARY

OF RESULTS:

A VVRS analysis of the as-left J-Groove weld on reactor vessel BMI nozzle #3 at Palo Verde Unit 3 has been performed. Appendix B and Appendix C provide stress results for use in downstream fracture mechanics analyses.

This is the Non-Proprietary version of 32-9215089-001.

The following table summarizes the total pages contained in this document.

I Section Main Bod I Appendix A I Appendix B I Appendix C T otlZZ 1 raes Z- 1 0 10 1 IZ I -F THE DOCUMENT CONTAINS ASSUMPTIONS THAT SHALL BE THE FOLLOWING COMPUTER CODES HAVE BEEN USED IN THIS DOCUMENT: VERIFIED PRIOR TO USE CODE/VERSION/REV CODENERSION/REV E]Yes ANSYS 14.5.7 / Windows 7 MNo Enclosure Attachment 3 Page 1 of 41

A 0402-01-FOI (Rev. 018, 01/30/2014)

ARE VA Document No. 32-9219662-000 Weld Residual Stress Analysis for PVNGS3 RV BMI Nozzle Repair (Non-Proprietary)

Review Method: rL Design Review (Detailed Check)

E Alternate Calculation Signature-Block P/RPA Name and Title and Pages/Sections (printed or typed) Signature LPILR Date Prepared/ReviewedlApproved Torm Riordan P All Engineer III9( /Vr 1ý ~ ISAf'2-Oij Silvester Noronha R All Principal Engineer Tim Wiger A All Engineering -  :/

Manager J Note: P/R/A designates Preparer (P), Reviewer (R), Approver (A);

LP/LR designates Lead Preparer (LP), Lead Reviewer (LR)

Project Manager Approval of Customer References (N/A if not applicable)

Name Title (printed or typed) (printed or typed) Signature Date Maya Chandrashekhar Project Manager Mentoring Information (not required per 0402-01)

Name Title Mentor to:

(prInted or typed) (printed or typed) (P/R) Signature Date N/A Enclosure Attachment 3 Page 2

A 0402-01-FOl (Rev. 018, 01/30/2014)

AREVA Document No. 32-9219662-000 Weld Residual Stress Analysis for PVNGS3 RV BMI Nozzle Repair (Non-Proprietary)

Record of Revision Revision PageslSectionslPa rag raphs No. Changed Brief Description IChange Authorization 000 All Oiia ees Enclosure Attachment 3 Page 3

A AREVA Document No. 32-9219662-000 Weld Residual Stress Analysis for PVNGS3 RV BMI Nozzle Repair (Non-Proprietary)

Table of Contents Page SIGNATURE BLOCK ................................................................................................................................ 2 RECORD OF REVISION .......................................................................................................................... 3 LIST OF TABLES ..................................................................................................................................... 5 LIST OF FIGURES ................................................................................................................................... 6 1.0 PURPOSE ..................................................................................................................................... 7 2.0 ANALYTICAL METHODOLOGY ............................................................................................... 7 3.0 ASSUM PTIONS ............................................................................................................................ 8 3.1 Unverified Assumptions .......................................................................................................... 8 3.2 Justified Assumptions ....................................................................................................................... 8 3.3 Modeling Simplifications .......................................................................................................... 8 4.0 DESIGN INPUTS .......................................................................................................................... 9 4 .1 G e om etry .......................................................................................................................................... 9 4 .2 Ma te ria ls ......................................................................................................................................... 10 4.3 Welding Parameters ....................................................................................................................... 12 4.4 Finite Element Model ...................................................................................................................... 13 4.5 Boundary Conditions ...................................................................................................................... 16 4.5.1 Thermal Boundary Conditions .................................................................................... 16 4.5.2 Structural Boundary Conditions ......... ;....................................................................... 16 5.0 COM PUTER USAGE .................................................................................................................. 18 5.1 Software .......................................................................................................................... 18 5 .2 C om p ute r F ile s ............................................................................................................................... 18 6.0 CALCULATIONS AND RESULTS ........................................................................................... 20

7.0 REFERENCES

............................................................................................................................ 23 APPENDIX A : VERIFICATION OF ANSYS COMPUTER CODE ............................................................... A-1 APPENDIX B: WRS RESULTS FOR AS-LEFT J-GROOVE WELD ANALYSIS ......................................... B-1 APPENDIX C: WRS RESULTS FOR NOZZLE FLAW EVALUATION ........................................................ C-1 Enclosure Attachment 3 Page 4

A AR EVA Document No. 32-9219662-000 Weld Residual Stress Analysis for PVNGS3 RV BMI Nozzle Repair (Non-Proprietary)

List of Tables Page Table 4-1: Key Dimensions .............................................................................................................. 9 Table 4-2: Component Materials ........................................................................................................ 10 Table 4-3: Room Temperature Thermal and Mechanical Properties ................................................ 10 Table 4-4: Welding Parameters ........................................................................................................ 12 Table 5-1: C om puter Files ..................................................................................................................... 18 Table C-1: Linearized Hoop Stress Results for WRS at Cold Shutdown ............................................. C-3 Table C-2: Linearized Hoop Stress Results for WRS plus Operating Condition .................................. C-5 Table C-3: Linearized Axial Stress Results for WRS at Cold Shutdown .............................................. C-7 Table C-4: Linearized Axial Stress Results for WRS plus Operating Condition .................................. C-9 Enclosure Attachment 3 Page 5

A AREVA Document No. 32-9219662-000 Weld Residual Stress Analysis for PVNGS3 RV BMI Nozzle Repair (Non-Proprietary)

List of Figures Page Figure 4-1: Room Temperature True Stress-True Plastic Strain Curves ......................................... 11 Figure 4-2: WRS Finite Element Model Isometric View ..................................................................... 13 Figure 4-3: Weld Region Mesh ........................................................................................................ . . 14 Figure 4-4: Butter Pass Sequence ................................................................................................... 14 Figure 4-5: J-Groove Weld Pass Sequence ..................................................................................... 15 Figure 4-6: Hypothetical Repair Weld Pass Sequence ..................................................................... 15 Figure 4-7: Elements to be Removed for Boat Sample Removal and Nozzle Severing Marked ..... 17 Figure 4-8: Boat Sample Removal and Nozzle Severing ................................................................... 17 Figure 6-1: Residual Hoop Stress (psi) at Cold Shutdown ................................................................ 21 Figure 6-2: Residual Axial Stress (psi) at Cold Shutdown ................................................................ 22 Figure B-1: Hoop Stresses Excluding Nozzle (psi) .............................................................................. B-2 Figure B-2: N ozzle H oop Stresses (psi) ............................................................................................... B -3 Figure C-1: Paths for Stress Results .............................................................................................. C-1 Figure C-2: Linearized Hoop Stress Results for WRS at Cold Shutdown ....................................... C-4 Figure C-3: Linearized Hoop Stress Results for WRS plus Operating Condition ................................ C-6 Figure C-4: Linearized Axial Stress Results for WRS at Cold Shutdown ............................................ C-8 Figure C-5: Linearized Axial Stress Results for WRS plus Operating Condition ............................ C.-10 Figure C-6: Residual Hoop Stress (psi) for WRS plus Operating Condition .................................. C-i 1 Figure C-7: Residual Axial Stress (psi) for WRS plus Operating Condition .................................. C-12 Enclosure Attachment 3 Page 6

A AR EVA Document No. 32-9219662-000 Weld Residual. Stress Analysis for PVNGS3 RV BMI Nozzle Repair (Non-Proprietary) 1.0 PURPOSE Visual inspection of the reactor vessel Bottom Mounted Instrument (BMI) nozzles at Palo Verde Nuclear Generation Station, Unit 3 (PVNGS3), in October of 2013 revealed the presence of boric acid crystals on the outside of the lower head at BMI nozzle #3. Boric acid deposits at the gap between the nozzle and head indicate leakage of primary water through cracks in the J-Groove weld and the nozzle wall. AREVA performed a half nozzle repair of nozzle #3 that maintained the full incore instrumentation functionality of the nozzle. This repair, described in References [1] and [2], moves the primary pressure boundary nozzle weld from the inside of the vessel to a weld pad on the outside surface. AREVA Document 51-9220420 (latest revision) provides a road map of the AREVA analyses for the Palo Verde BMI Nozzle.

The purpose of this report is to document the weld residual stress (WRS) finite element analysis of the as-left J-Groove weld for use in subsequent fracture mechanics analysis.

2.0 ANALYTICAL METHODOLOGY The WRS finite element analysis is carried out utilizing the methodology developed in Reference [3]. The methodology developed in Reference [3] has been successfully benchmarked to mock-up samples and industry round-robin tests in papers such as References [4] and [5], which gives a high level of confidence in its predictive capabilities. In addition, the methodology is consistent with the general recommendations of industry WRS modeling guidance documents such as MRP-317 (Reference [6]).

The fabrication history of BMI nozzle #3 is simulated by the three-dimensional finite element model using the following sequential steps:

1. Multi-pass welding of the Alloy 182 J-Groove buttering. A total of five analytical weld beads are utilized for the buttering weld.
2. Post-weld heat treatment (PWHT) of the buttered low alloy steel head. Note that the stainless steel cladding has already been added to the inner surface of the head as stress free material.
3. Multi-pass J-Groove welding of the original Alloy 600 nozzle to the buttered low alloy steel head. A total of 15 analytical weld beads are used for the J-Groove weld.
4. Hypothetical weld repair by removal of a portion of the J-Groove weld and re-welding this area. A total 10 analytical weld beads covering half the circumference were removed and re-welded for the J-Groove weld repair.
5. Hydrostatic pressure testing performed in the shop and field.
6. Three cycles of operating conditions at steady state pressure and temperature. These multiple static load steps are meant to capture any "shakedown" of residual stress with operation.
7. Removal of the boat sample and severing the existing nozzle at the appropriate elevation.

The general purpose finite element code ANSYS is used to perform the WRS finite element analysis. The finite element analysis is based on a 3-dimensional model. The basic steps comprising the multi-pass welding simulation of the buttering, and J-Groove weld are as follows:

Enclosure Attachment 3 0O~yd7t

A AR EVA Document No. 32-9219662-000 Weld Residual Stress Analysis for PVNGS3 RV BMI Nozzle Repair (Non-Proprietary)

Static load steps are applied to simulate hydrostatic testing and operation after the simulation of the J-Groove welding. Additional static load steps are used to simulate the boat sample removal and severing of the existing nozzle at an appropriate elevation.

3.0 ASSUMPTIONS 3.1 Unverified Assumptions No unverified assumptions are used in this calculation.

3.2 Justified Assumptions The following justified assumptions are used in this calculation:

1. Cladding is added to the Reactor Vessel Bottom Head (RVBH) as stress free material. This is a reasonable assumption since the RVBH along with the cladding receives post-weld heat treatment.
2. The recently performed half-nozzle repair weld at the OD surface (Reference [2]) is not modeled; since this area is remote from the as-left J-Groove weld the impact on the stresses in the as-left J-Groove weld will be negligible. Additionally, it is expected that the residual stresses from the repair pad welding would be tensile in the deposited repair weld pad balanced by compressive stresses in the RVBH; thus the simplification is conservative for the as-left weld since no credit would be taken for any compressive stress induced by the repair.

3.3 Modeling Simplifications The following modeling simplifications are used in this calculation:

1. A half model is considered due to the symmetry of the components.
2. The boat sample geometry (Reference [7]) is approximated, as described in the following sentences. The boat sample removal is simulated by selecting and "killing" a set of elements, which results in a "jagged" boundary. This approach is taken in order to maintain a high quality hexahedral mesh for the rest of the simulation. This approach is reasonable since the impact of the resultantrgeometry on stresses will be local to the elements near this "jagged" boundary and overall equilibrium is maintained in the finite element solution. Additionally, the boat sample is considered to be centered on the symmetry plane on the uphill side in order to maintain a symmetric model.

Enclosure Attachment 3 Page 8

A AREVA Document No. 32-9219662-000 Weld Residual Stress Analysis for PVNGS3 RV BMI Nozzle Repair (Non-Proprietary)

3. There is no contribution to the WRS field predicted in this document due to any interaction with the surrounding penetrations. This is a reasonable assumption since the surrounding penetrations are spaced far enough away from the modeled BMI nozzle penetration to preclude interaction of the residual stress fields.
4. Simulation of PWHT does not include creep. This is a conservative simplification since creep would reduce the residual stress in the RVBH and butter.
5. The weld bead sequence follows the recommendation of Reference [8] to the extent practical, however, the analytical weld beads typically lump together several actual weld beads, which is an acceptable practice in numerical welding simulations. The welding simulation performed here uses five analytical weld beads for the buttering weld passes, 15 analytical weld beads for the J-Groove weld passes, and 10 analytical weld beads covering half the circumference for the J-Groove weld repair passes. The analytical weld beads and pass sequence are shown in Figure 4-4, Figure 4-5, and Figure 4-6.

4.0 DESIGN INPUTS 4.1 Geometry Details of the geometry are provided in References [9], [10], [11], and [12]. Key dimensions are listed in Table 4-1.

Table 4-1: Key Dimensions Description Value Reference/Comments RVBH Inside Radius [ ] Reference [9]

RVBH Thickness [ ] Reference [9]

Cladding Thickness [ ] Reference [9]

Nozzle OD [ J Reference [10]

Nozzle ID [ ] Reference [10]

Height of J-Groove plus Fillet [ Reference [11]

Butter Thickness j [ Reference [12]

Enclosure Attachment 3 Page 9

A AREVA Document No. 32-9219662-000 Weld Residual Stress Analysis for PVNGS3 RV BMI Nozzle Repair (Non-Proprietary) 4.2 Materials The materials of each component are listed in Table 4-2.

Table 4-2: Component Materials Component Material ReferencelComments RVBH SA-533 Grade B Class 1 Reference [1]

BMI Nozzle SB-166 Alloy 600 Reference [1]

Cladding Austenitic Stainless Steel (304) Reference [1], 18-24Cr, 8-12Ni per Reference [ 18], Section 4.7.4 Buttering Alloy 182 (ENiCrFe-3) Reference [1]

J-Groove Weld Alloy 82 (ERNiCr-3) Reference [1]

The analysis in this calculation uses physical properties (thermal conductivity, specific heat, density, mean coefficient of thermal expansion, elastic modulus, and Poisson's ratio) from Reference [ 13]. Properties for SA-533, Grade B, Class I are not directly available in Reference [13]; properties from SA-508 are utilized since they were found to be similar for both low alloy steels based on review of original construction code (Reference [ 14]),

which provides the same specified minimum yield and tensile strengths for both materials as well as the same thermal and mechanical properties. All physical and mechanical properties except Poisson's ratio are temperature dependent; these properties are defined in ANSYS input file "thermomech.inp". The room temperature thermal and mechanical properties used in the analysis are provided in Table 4-3.

Table 4-3: Room Temperature Thermal and Mechanical Properties SA-533 Alloy 600 Alloy 82/182 304 Stainless Density (Ibm/in 3) [ ] [ ] [ ] [ ]

Thermal Conductivity (BTU/s-in-°F) [ ] C ] [ ] C ]

Specific Heat (BTU/Ibm-°F) [ ] [ ] C ] [ ]

Elastic Modulus (psi) [ ] [ I C ] C ]

Poisson's Ratio (-) [ I [ I C 1 C I Mean CTE (/OF) [ I [ I [ I C I The temperature dependent stress-strain curves for each material are also from Reference [13]. Stress-strain curves for the SA-533 and the Alloy 600 have been modified slightly based on the CMTRs (References [ 15] and

[16]) for these materials using the following procedure:

1. Calculate the ratios of room temperature yield and ultimate strength from the CMTRs to the room temperature values from the WRS materials database (Reference [13]). Note that the values from the WRS database are first converted to engineering stress to be consistent with the CMTR data.
2. Multiply the WRS database yield and ultimate stress values at each temperature by these ratios. For points between yield and ultimate a ratio is determined by linear interpolation between the yield ratio and ultimate ratio based on strain.
3. For the SA-533 material the ratio of yield stress was higher than the ratio of ultimate stress. At high temperatures where the stress-strain curves are nearly perfectly plastic steps I and 2 can result in yield Enclosure Attachment 3 Page 10

A AREVA Document No. 32-9219662-000 Weld Residual Stress Analysis for PVNGS3 RV BMI Nozzle Repair (Non-Proprietary) stresses higher than ultimate; in these cases all values higher than the calculated ultimate stress were set equal to the calculated ultimate stress.

The above procedure results in the WRS simulation using room temperature stress strain curves for the Alloy 600 and SA-533 that have yield and ultimate strengths approximately equal to those from the CMTRs. This increased the SA-533 stress-strain curves [ I over the WRS database values (Reference [13]) and decreased the Alloy 600 stress-strain curves I ] from the WRS database values (Reference

[13]). The resulting temperature dependent true stress-strain curves are defined utilizing the multi-linear kinematic hardening model in ANSYS input file "kinhprops-CMTR.inp". The room temperature true stress-true plastic strain curves utilized are shown in Figure 4-1.

Figure 4-1: Room Temperature True Stress-True Plastic Strain Curves Enclosure Attachment 3 Page 11

A AREVA Document No. 32-9219662-000 Weld Residual Stress Analysis for PVNGS3 RV BMI Nozzle Repair (Non-Proprietary) 4.3 Welding Parameters The welding process parameter assumptions provided in Reference [8] are utilized to establish the welding heat generation in the finite element model of the butter, J-Groove weld, and the hypothetical J-Groove weld repair.

The parameters utilized are provided in Table 4-4. The analytical weld bead sequences are shown in Figure 4-4, Figure 4-5, and Figure 4-6. Based on the information provided in Reference [8], the hypothetical J-Groove weld repair shown in Figure 4-6 is postulated to cover one half of the circumference and replaces 10 of the original 15 analytical weld beads.

Table 4-4: Welding Parameters Parameter Value Units Reference/Comments Butter Layer/s Current Amps Reference [8], average of two layers Voltage [Volts Reference [8], average of two layers Travel Speed ] in/m Reference [8], average of two layers Arc Efficiency [- Reference [3]

Maximum Interpass Temperature 7 Reference [3]

J-Groove Layers 1-3" Current [ ] Amps Reference [8]

Voltage [ ] Volts Reference [8]

Travel Speed [ ] in/min Reference [8]

Arc Efficiency [ ] - Reference [3]

Maximum Interpass Temperature ] 0' F Reference [3]

J-Groove Balance of Layers and HypotheticalJ-GrooveRepair**

Current [ ] Amps Reference [8]

Voltage [ ] Volts Reference [8]

Travel Speed [ ] in/min Reference [8]

Arc Efficiency I -- Reference [3]

Maximum Interpass Temperature [ I F Reference [31

  • Used for analytical J-Groove weld beads 1-3.
    • Used for all other analytical J-Groove weld beads and the hypothetical J-Groove repair weld.

Enclosure Attachment 3 Page 12

A AREVA Document No. 32-9219662-000 Weld Residual Stress Analysis for PVNGS3 RV BMI Nozzle Repair (Non-Proprietary) 4.4 Finite Element Model The finite element model utilized is a three-dimensional half symmetry model. The mesh consists of 8-node brick elements which are ANSYS element type SOLID70 for thermal analyses and SOLID185 for stress analyses.

CONTA174 and TARGE170 elements are used to simulate contact between the nozzle and the RVBH. Weld metal deposition and material removal are simulated using the ANSYS elements "birth and death" feature. The finite element model is documented in the ANSYS input file "BMINozzle 3.inp".

The finite element mesh is shown in Figure 4-2 and Figure 4-3. The weld passes utilized for the butter, J-Groove weld, and J-Groove weld repair are based on the recommendations in Reference [8]; the pass sequences are depicted in Figure 4-4, Figure 4-5, and Figure 4-6.

Figure 4-2: WRS Finite Element Model Isometric View Enclosure Attachment 3 Page 13

A AREVA Document No. 32-9219662-000 Weld Residual Stress Analysis for PVNGS3 RV BMI Nozzle Repair (Non-Proprietary)

Figure 4-3: Weld Region Mesh Figure 4-4: Butter Pass Sequence Enclosure Attachment 3 Page 14

A AREVA Document No. 32-9219662-000 Weld Residual Stress Analysis for PVNGS3 RV BMI Nozzle Repair (Non-Proprietary)

Figure 4-5: J-Groove Weld Pass Sequence Figure 4-6: Hypothetical Repair Weld Pass Sequence Enclosure Attachment 3 Page 15

A ARE VA Document No. 32-9219662--000 Weld Residual Stress Analysis for PVNGS3 RV BMI Nozzle Repair (Non-Proprietary) 4.5 Boundary Conditions 4.5.1 Thermal Boundary Conditions The thermal model is loaded by volumetric heat generation in the elements of the weld pass being deposited. An adiabatic boundary condition is applied to the model symmetry plane and the RVBH cutting planes. Heat loss from the inner and outer surfaces is simulated using a heat transfer coefficient of [ I per the Reference [3] WRS procedure to model natural convection to air. Radiation boundary conditions are not considered since radiation losses from the molten weld pool are included in the weld efficiency.

The thermal simulations for the buttering, J-Groove weld, and the J-Groove weld repair are performed by the input files "ThermalButter.inp", "ThermalJGW.inp", and "ThermalJGWRepair.inp", respectively.

4.5.2 Structural Boundary Conditions The structural simulations consist of buttering, PWHT, J-Groove weld passes, J-Groove weld repair, hydrostatic test, operating cycles and boat sample removal. In all cases, rigid body motion is eliminated by restraining displacements normal to the symmetry plane and RVBH cutting planes.

For the weld pass simulations, temperature histories from the thermal analyses are used as thermal loads in the structural analysis. A traction free boundary condition (i.e., no applied forces) is maintained on all external surfaces of the model. Weld pass simulations for the buttering, J-Groove weld, and the J-Groove weld repair are performed by the input files "StressButter.inp", "StressJGW.inp", and "Stress JGWRepair.inp", respectively.

PWHT of the RVBH, clad and butter is simulated by applying a uniform temperature of [ ], which is the PWHT temperature for the RVBH material per Reference [ 17]. A traction free'boundary condition is maintained on all external surfaces of the model. The PWHT analysis is performed by the input file "Stress_PWHT.inp".

Following the completion of the weld pass simulations, two hydrostatic test cycles apply a pressure of [

I on the wetted surfaces and a uniform temperature of [ ] (Reference [18], page 11). Subsequently, three cycles of normal operating conditions are simulated using the normal operating pressure of [

on the wetted surfaces and a uniform temperature equal to the inlet water temperature of

[ (Reference [18], page 10). The condition with a temperature of [ ] with a pressure of

] is subsequently referred to as "operating" or "operating condition" in this calculation. The hydrostatic test and operating cycles are simulated using the input file "StressHydroOpCond.inp".

The boat sample removal and nozzle severing are simulated by "killing" the relevant elements and solving with no loads applied at a temperature of [ ]. The condition with a temperature of [ ] with no loads applied is subsequently referred to as "cold shutdown" in this calculation. Simulation of the boat sample removal and nozzle severing is performed by the input file "StressBoat.inp". Elements "killed" to simulate the boat sample and cutting of the nozzle are indicated in Figure 4-7 and shown as removed in Figure 4-8.

Enclosure Attachment 3 Page 16

A AREVA Document No. 32-9219662-000 Weld Residual Stress Analysis for PVNGS3 RV BMI Nozzle Repair (Non-Proprietary)

Figure 4-7: Elements to be Removed for Boat Sample Removal and Nozzle Severing Marked Figure 4-8: Boat Sample Removal and Nozzle Severing Enclosure Attachment 3 Page 17

A AREVA Document No. 32-9219662-000 Weld Residual Stress Analysis for PVNGS3 RV BMI Nozzle Repair (Non-Proprietary) 5.0 COMPUTER USAGE 5.1 Software ANSYS Version 14.5.7 (Reference [ 191) was used in this analysis. All modeling and analyses were performed on the following computer:

  • DELL Precision M6600, Intel(R) Core(TM) i7-2640M CPU @ 2.80GHz, 8GB of RAM
  • Operating System: Windows 7, Service Pack 1, 64 Bit

" Name of person running tests: Tom Riordan

  • Date of Tests: January 14, 2014 The test problems vm32mod2d, v32mod3d, vm38mod2d, and vm38mod3d were executed with acceptable results.

See Appendix A for details of the test cases.

5.2 Computer Files The ANSYS input and output files are listed in Table 5-1. Files are store in ColdStor at the following path:

\cold\General-Access\32\32-9000000\32-9215089-000\official Table 5-1: Computer Files Size (Bytes) Date Time File Name

./AppC:

1413 Jan 17 2014 13:03:38 StressOp.inp 10252 Jan 17 2014 14:03:33 StressOp.out 1779 Jan 21 2014 11:40:21 WRSOP mb sum.dat 1779 Mar 11 2014 6:47:01 WRSOP mb sumax.dat 87023 Jan 21 2014 11:40:21 WRS OP paths.dat 87023 Mar 11 2014 6:47:01 WRS OP pathsax.dat 1779 Jan 21 2014 11:40:39 WRS mb sum.dat 1779 Mar 11 2014 6:47:21 WRS mb sumax.dat 87023 Jan 21 2014 11:40:39 WRS-paths.dat 87023 Mar 11 2014 6:47:21 WRSpaths ax.dat 1959 Jan 21 2014 9:54:47 linearize.mac 1965 Mar 11 2014 6:41:59 linearizeax.mac 261 Jan 21 2014 9:23:08 Ioc_data.inp 3476 Jan 21 2014 11:35:16 path_results_WRS.inp 35695 Jan 21 2014 11:40:39 path_resultsWRS.out 3462 Jan 21 2014 11:26:52 path_resultsWRSOP.inp 35762 Jan 21 2014 11:40:21 pat h_resultsWRS_OP.out 3479 Mar 11 2014 6:46:28 path_results_WRSOPax.inp 35823 Mar 11 2014 6:47:02 path_resultsWRSOP ax.out 3490 Mar 1 2014 6:46:31 path_resultsWRS-ax.inp 35781 Mar 11 2014 6:47:21 path_resultsWRSax.out Enclosure Attachment 3 Page 18

A AREVA Document No. 32-9219662-000 Weld Residual Stress Analysis for PVNGS3 RV BMI Nozzle Repair (Non-Proprietary)

Size (Bytes) Date Time File Name

./Materials:

4859 Jan 10 2014 13:55:15 kinhprops-CMTR.inp 4494 Dec 10 2013 9:58:46 kinh_props.inp 26432 Dec 03 2013 14:32:01 thermomech.inp

./Model:

11647432 Jan 03 2014 11:27:31 BMINozzle_3.inp

./Post:

534467 Jan 20 2014 8:08:55 WRS.sav 2061 Jan 15 2014 14:30:00 extractnodalstress.inp 18148 Jan 20 2014 8:08:55 extractnodalstress.out

./Stress:

2188 Nov 19 2013 10:46:09 AnnealMaterial3D.mac 855 Jan 17 2014 12:03:41 StressBoat.inp 9548 Jan 17 2014 13:12:17 StressBoat.out 4683 Jan 10 2014 17:54:28 StressButter.inp 24564 Jan 11 2014 0:12:24 StressButter.out 2268 Jan 03 2014 13:00:42 StressHydroOpCond.inp 11477 Jan 12 2014 18:23:02 StressHydroOpCond.out 2955 Jan 03 2014 12:24:48 StressJGW.inp 20473 Jan 11 2014 22:30:43 StressJGW.out 2718 Jan 03 2014 12:28:26 StressJGW_Repair.inp 20178 Jan 12 2014 17:42:06 StressJGW_Repair.out 899 Dec 02 2013 9:16:26 StressPWHT.inp 9474 Jan 11 2014 0:20:30 StressPWHT.out

./Thermal:

576 Feb 16 2012 13:35:22 GetEstTime3.mac 493 Feb 16 2012 13:35:22 GetDeltaTControls.mac 998 Feb 16 2012 13:34:59 SummarizeWeldBeadTemp.mac 598 Feb 17 2012 17:03:34 TempCheckCooldown.mac 659 Feb 17 2012 16:55:29 TempCheckHeatup.mac 9901 Dec 16 2013 8:10:07 Thermal_Butter.inp 133351 Jan 08 2014 18:07:55 ThermalButter.out 9745 Dec 16 2013 8:12:28 Thermal_JGW.inp 23277 Jan 08 2014 20:09:03 ThermalJGW.out 8957 Dec 16 2013 8:11:27 ThermalJGWRepair.inp 22302 Jan 08 2014 22:29:02 ThermalJGWRepair.out Enclosure Attachment 3 Page 19

A AREVA Document No. 32-9219662-000 Weld Residual Stress Analysis for PVNGS3 RV BMI Nozzle Repair (Non-Proprietary)

Size (Bytes) Date Time File Name

./Verification:

3551 Jan 05 2009 9:09:26 vm32mod2D.inp 55666 Jan 14 2014 10:53:11 vm32mod2D.out 624 Jan 14 2014 10:53:11 vm32mod2D.vrt 4940 Jan 06 2009 12:15:42 vm32mod3D.inp 111280 Jan 14 2014 10:53:14 vm32mod3D.out 624 Jan 14 2014 10:53:14 vm32mod3D.vrt 2458 Jan 07 2009 10:28:06 vm38mod2D.inp 14361 Jan 14 2014 10:53:17 vm38mod2D.out 650 Jan 14 2014 10:53:17 vm38mod2D.vrt 3112 Jan 07 2009 10:35:54 vm38mod3D.inp 16834 Jan 14 2014 10:53:20 vm38mod3D.out 650 Jan 14 2014 10:53:19 vm38mod3D.vrt 6.0 CALCULATIONS AND RESULTS After completion of the J-Groove welding simulation, two hydrostatic test cycles, three normal operating cycles and the removal of the boat sample are simulated. The residual hoop stresses at cold shutdown are shown in Figure 6-1. The residual axial stresses are shown in Figure 6-2.

The subsequent fracture mechanics analysis will utilize explicit crack finite element models for calculation of stress intensity factors for postulated flaws in the J-Groove weld and butter. To facilitate this analysis, nodal hoop stresses on the symmetry plane are extracted and provided in Appendix B.

Appendix C provides results of the case with operating temperature and pressure applied after the removal of the boat sample; stress results on path lines in the nozzle are provided for evaluation of flaws in the nozzle.

Enclosure Attachment 3 Page 20

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Figure 6-1: Residual Hoop Stress (psi) at Cold Shutdown Enclosure Attachment 3 Page 21

A AREVA Document No. 32-9219662-000 Weld Residual Stress Analysis for PVNGS3 RV BMI Nozzle Repair (Non-Proprietary)

Figure 6-2: Residual Axial Stress (psi) at Cold Shutdown Enclosure Attachment 3 Page 22

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7.0 REFERENCES

References identified with an (*)are maintained within Palo Verde Nuclear Generating Station Records System and are not retrievable from AREVA Records Management. These are acceptable references per AREVA Administrative Procedure 0402-01, Attachment 8. See page 2 for Project Manager Approval of customer references.

1. AREVA Document 08-9212780-001, "Palo Verde Unit 3 Reactor Vessel Bottom Mounted Instrument Nozzle Modification".
2. AREVA Document 02-9212754E-001, "Palo Verde Unit 3 Bottom Mounted Instrument Nozzle Repair (Penetration 3)".
3. AREVA Document 32-2500013-001, "Technical Basis for Numerical Simulation of Welding Residual Stresses".
4. D.E. Killian, "Design of a Weld Overlay for a Large Bore Pipe Nozzle to Optimize Residual Stress",

PVP2010-26100, Proceedings of the ASME 2010 Pressure Vessels & Piping Division Conference, July 18-22, Bellevue, Washington, USA.

5. D.E. Killian, "Validation of Welding Residual Stress Model Using Results from a Pressurizer Surge Nozzle Mockup", PVP2011-57767, Proceedings of the ASME 2011 Pressure Vessels & Piping Division Conference, July 17-21, Baltimore, Maryland, USA.
6. "Materials Reliability Program: Welding Residual Stress Dissimilar Metal Butt-Weld Finite Element Modeling Handbook (MRP-317)". EPRI, Palo Alto, CA: 2011. 1022862.
7. *PVNGS Document NOO1-0301-00633, Revision 0, "Boat Sample Extraction General Layout Drawing".
8. AREVA Document 51-9213228-001, "Palo Verde Unit 3 - Partial Penetration J-Groove Welding Heat Input Assumptions for Bottom Mounted Instrumentation Nozzle to Head Welding".
9. *PVNGS Document NOO1-0301-00054, Revision 2, "General Arrangement Arizona Public Service III 182.25 ID Reactor Vessel"
10. *PVNGS Document NOO1-0603-00208, Revision 3, "Bottom Head Instrument Tubes".
11. *PVNGS Document N001-0301-00527, Revision 0, "Lower Vessel Final Assembly - Arizona Public Service III, 182.25 ID PWR".
12. *PVNGS Document NOO1-0301-00530, Revision 0, "Bottom Head Penetrations - Arizona Public Service III, 182.25 ID PWR".
13. AREVA Document 32-2500012-002, "Materials Database for Weld Residual Stress Finite Element Analyses".
14. ASME Boiler and Pressure Vessel Code,Section III, "Nuclear Power Plant Components", Division 1, 1971 Edition including Addenda through Winter 1973.
15. *Palo Verde Unit 3 Bottom Head CMTR.
16. *Palo Verde Unit 3 Alloy 600 Bottom Mounted Nozzle CMTR.
17. *PVNGS Document CVER-13-281, "Transmittal of Palo Verde Unit 3 Bottom Head Postweld Heat Treatment (PWIHT) and Materials", October 28, 2013.
18. *PVNGS Document NOO1-0301-00006, Revision 6, "General Specification for Reactor Vessel Assembly".
19. ANSYS Finite Element Computer Code, Version 14.5, ANSYS Inc., Canonsburg, PA.

Enclosure Attachment 3 Page 23

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APPENDIX A: VERIFICATION OF ANSYS COMPUTER CODE Four verification problems were selected to test key features of the ANSYS finite element computer program (Reference [ 19]) used in the current numerical welding simulations, the development of thermal stress in a cylinder and the elastic-plastic response of a cylinder under pressure loading.

All test cases executed properly, as demonstrated on the following pages.

Enclosure Attachment 3 Page A-1

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Verification Problem VM32MOD Thermal Stresses in a Long Cylinder Two-Dimensional Analysis File: vm32mod2d.vrt

VM32MOD2D RESULTS COMPARISON----------------

I TARGET I ANSYS I RATIO PLANE55 THERMAL ANALYSIS:

T (C) X=.1875 in -1.00000 -1.00000 1.000 T (C) X=.2788 in -0.67037 -0.67039 1.000 T (C) X=0.625 in 0.00000 0.00000 0.000 PLANE182 STATIC ANALYSIS:

A_STS psi X=.187 420.42 429.99 1.023 T STS psi X=.187 420.42 429.61 1.022 A_STS psi X=.625 -194.58 -205.15 1.054 T_STS psi X=.625 -194.58 -205.08 1.054 Three-Dimensional Analysis File: vm32mod3d.vrt

- VM32MOD3D RESULTS COMPARISON I TARGET I ANSYS I RATIO SOLID70 THERMAL ANALYSIS:

T (C) X=.1875 in -1.00000 -1.00000 1.000 T (C) X=.2788 in -0.67037 -0.67039 1.000 T (C) X=0.625 in 0.00000 0.00000 0.000 SOLID185 STATIC ANALYSIS:

A_STS psi X=.187 420.42 429.67 1.022 T_STS psi X=.187 420.42 430.04 1.023 A STS psi X=.625 -194.58 -205.11 1.054 T STS psi X=.625 -194.58 -205.17 1.054 Enclosure Attachment 3 Page A-2

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Verification Problem VM38MOD Plastic Loading of a Thick-Walled Cylinder Two-Dimensional Analysis File: vm38mod2d.vrt

-------- VM38MOD2D RESULTS COMPARISON-----------------

I TARGET I ANSYS I RATIO PLANE182 FULLY ELASTIC ANALYSIS (psi):

SIGR LEFT END -9984. -10103. 1.012 SIGT LEFT END 18645. 18763. 1.006 SIGR RIGHT END -468. -481. 1.028 SIGT RIGHT END 9128. 9141. 1.001 PLANE182 FULLY PLASTIC ANALYSIS (psi):

SIGEFF LEFT END 30000. 30000. 1.000 SIGEFF RIGHT END 30000. 30000. 1.000 Pult 24011. 23350. 0.972 Three-Dimensional Analysis File: vm38mod3d.vrt

VM38MOD3D RESULTS COMPARISON-----------------

I TARGET I ANSYS I RATIO SOLID185 FULLY ELASTIC ANALYSIS (psi):

SIGR LEFT END -9984. -10066. 1.008 SIGT LEFT END 18645. 18776. 1.007 SIGR RIGHT END -468. -475. 1.014 SIGT RIGHT END 9128. 9128. 1.000 SOLID185 FULLY PLASTIC ANALYSIS (psi):

SIGEFF LEFT END 30000. 30000. 1.000 SIGEFF RIGHT END 30000. 30000. 1.000 Pult 24011. 23360. 0.973 Enclosure Attachment 3 Page A-3

A AR EVA Document No. 32-9219662-000 Weld Residual Stress Analysis for PVNGS3 RV BMI Nozzle Repair (Non-Proprietary)

APPENDIX B: WRS RESULTS FOR AS-LEFT J-GROOVE WELD ANALYSIS This appendix provides the weld residual stress results to be used for evaluation of postulated flaws in the J-Groove weld, butter, head. Node locations on the symmetry plane and the corresponding hoop stresses are extracted and saved in the file "WRS.sav" (see Table 5-1) as ANSYS array parameters. The stresses extracted are from the final step of the WRS simulation, i.e., boat sample removed at cold shutdown. [

]; this ensures that stresses can be mapped to and from the correct body (nozzle or RVBH) in areas where the gap between the two is small. The extraction of the nodal stresses is performed by the file "extractnodal_stress.inp".

ANSYS arrays containing the extracted data are:

10c_noz = Nozzle node locations (1027x3) sznoz = Nozzle hoop stresses (1027x1) loc = Node locations excluding nozzle (1439x3) sz = Hoop stresses excluding nozzle (1439xl)

Plots of the extracted hoop stress data are shown in Figure B-1 and Figure B-2.

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Figure B-I: Hoop Stresses Excluding Nozzle (psi)

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Figure B-2: Nozzle Hoop Stresses (psi)

Enclosure Attachment 3 Page B-3

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APPENDIX C: WRS RESULTS FOR NOZZLE FLAW EVALUATION The purpose of this appendix is to provide WRS results for evaluation of flaws in the existing (remnant) nozzle.

Since the remnant nozzle material is Alloy 600 this appendix runs an additional load step in which operating pressure and temperature are applied to the model following removal of the boat sample and the bottom portion of the nozzle; this provides a WRS plus operating stress state for PWSCC flaw growth evaluations. This step is performed by the ANSYS input file "StressOp.inp". Contour plots showing the WRS plus operating hoop and axial stress results are shown in Figure C-6 and Figure C-7, respectively.

Stress results will be provided for WRS only at cold shutdown (generated by input files: "pathresults_WRS.inp" and "pathresults_WRSax.inp") as well as the WRS plus operating conditions case (generated by input files:

"path resultsWRSOP.inp" and "path results_WRS OP ax.inp").[

1=

Figure C-1: Paths for Stress Results Enclosure Attachment 3 Page C-1

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Hoop stress results along the path lines are provided in the files below (see also Table 5-1):

"WRS_paths.dat" = Path hoop stress results for WRS at cold shutdown.

"WRSOP-paths.dat" = Path hoop stress results for WRS plus Operating Condition.

"WRS mb sum.dat" Path hoop membrane and membrane plus bending results for WRS at cold shutdown.

"WRSOP mb sum.dat" Path hoop membrane and membrane plus bending results for WRS plus Operating Condition.

"WRS_pathsax.dat" = Path axial stress results for WRS at cold shutdown.

"WRSOP-pathsax.dat" = Path axial stress results for WRS plus Operating Condition.

"WRS mb sum ax.dat" Path axial membrane and membrane plus bending results for WRS at cold shutdown.

"WRSOP mb sum ax.dat" Path axial membrane and membrane plus bending results for WRS plus Operating Condition.

Detailed results of hoop stress vs path location are provided in the "*_paths.dat" and "*_paths ax.dat" files for each path. [

The "* mb sum.dat" and "* mb sumax.dat" files contain membrane and membrane plus bending hoop stress results which are calculated by the ANSYS macro file "linearize.mac" and "linearize ax.mac". The membrane stress is calculated using numerical integration as follows:

1 i=n-i 1 t/2 M-* = ydx = -- 2 t J-t/2 Xn-X 1 i=1 where t is the wall thickness, x is the path coordinate, a is the stress (hoop or axial), n is the number of points on the path, and Ax is the distance between adjacent points on the path. The bending component of stress is calculated similarly using 6 t/2 ax-xd 6 2i t-ri+U+tlXi + Xi+1 Xl +Xn) Ax 6r = -t/2 6xn

- 2 2 where xC is the path coordinate of the wall midpoint.

The membrane and membrane plus bending hoop stress results for WRS at cold shutdown (from "WRS mb sum.dat") and for WRS plus operating condition (from "WRS OP mb sum.dat") are provided in Table C-I and Table C-2, respectively. The hoop stresses are plotted in Figure C-2 and Figure C-3. The membrane and membrane plus bending axial stress results for WRS at cold shutdown (from "WRS mb sumax.dat") and for WRS plus operating condition (from "WRS OP mb sumac.dat") are provided in Table C-3 and, Table C-4 respectively. The axial stresses are plotted in Figure C-4 and Figure C-5. Note that cold shutdown and operating condition are as defined in Section 4.5.2. In all cases, the membrane plus bending stress on the OD is membrane stress minus the reported bending stress, and the membrane plus bending on the ID is membrane stress plus the reported bending stress. In all plots the location of path P 12 is set to elevation zero and the locations of path P1 and P23 are indicated on each plot. As shown in the tables and plots hoop stresses are dominant.

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Table C-1: Linearized Hoop Stress Results for WRS at Cold Shutdown Enclosure Attachment 3 Page C-3

A AREVA Document No. 32-9219662-000 Weld Residual Stress Analysis for PVNGS3 RV BMI Nozzle Repair (Non-Proprietary)

Figure C-2: Linearized Hoop Stress Results for WRS at Cold Shutdown Enclosure Attachment 3 Page C-4

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Table C-2: Linearized Hoop Stress Results for WRS plus Operating Condition Enclosure Attachment 3 Page C-5

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Figure C-3: Linearized Hoop Stress Results for WRS plus Operating Condition Enclosure Attachment 3 Page C-6

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Table C-3: Linearized Axial Stress Results for WRS at Cold Shutdown Enclosure Attachment 3 Page C-7

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Figure C-4: Linearized Axial Stress Results for WRS at Cold Shutdown Enclosure Attachment 3 Page C-8

A AREVA Document No. 32-9219662-000 Weld Residual Stress Analysis for PVNGS3 RV BMI Nozzle Repair (Non-Proprietary)

Table C-4: Linearized Axial Stress Results for WRS plus Operating Condition Enclosure Attachment 3 Page C-9

A AREVA Document No. 32-9219662-000 Weld Residual Stress Analysis for PVNGS3 RV BMI Nozzle Repair (Non-Proprietary)

Figure C-5: Linearized Axial Stress Results for WRS plus Operating Condition Page 0-10 Enclosure Attachment 3 Enclosure Attachment 3 Page C -10

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Figure C-6: Residual Hoop Stress (psi) for WRS plus Operating Condition Enclosure Attachment 3 Page C-11

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Figure C-7: Residual Axial Stress (psi) for WRS plus Operating Condition Enclosure Attachment 3 Page C-12

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