ML100250132

0800368.404, Revision 1, Leak-Before-Break Evaluation of Reactor Coolant Pump Suction and Discharge Nozzle Weld Overlays for Davis-Besse Nuclear Power Station, Enclosure B

ML100250132
Person / Time
Site:	Davis Besse
Issue date:	01/11/2010
From:	Miessi G, Qian H Structural Integrity Associates
To:	FirstEnergy Nuclear Operating Co, Office of Nuclear Reactor Regulation
References
FENOC PO 55108613, L-10-027, TAC ME2310, WSI PO 49151 0800368.404, Rev 1
Download: ML100250132 (107)

Text

Enclosure B L-10-027 Structural Integrity Associates, Inc. Report Number 0800368.404, Revision 1, January 11, 2010 [NONPROPRIETARY]

(87 pages follow)

Report No. 0800368.404 Revision: 1 Project No. 0800368 January 11, 2010

[ Q F-- Non-Q Leak-Before-Break Evaluation I of Reactor Coolant Pump Suction and Discharge Nozzle Weld Overlays for Davis-Besse Nuclear Power Station Preparedfor.

FirstEnergy Nuclear Operating Company FENOC PO 55108613 WSI PO 49151 Preparedby.

Structural Integrity Associates, Inc.

San Jose, California Preparedby: Date: 01/11/10 HG'Q 1Mies Preparedby: Date: 01/11/10

' G. A. Mies'si Reviewed by: Date: 01/11/10 A. F.Deardof Approved by: Date: 01/11/10 V StructuralIntegrity Associates, Inc.

REVISION CONTROL SHEET Document Number: 0800368.404

Title:

Leak-Before-Break Evaluation of Reactor Coolant Pump Suction and Discharge Nozzle Weld Overlays for Davis-Besse Nuclear Power Station Client: FirstEnergy Nuclear Operating Company SI Project Number: 0800368 Z Q E] Non-Q Section Pages Revision Date Comments All All 0 07/20/2009 Initial Issue 3,4,6 and Various as 1 1/11/2010 Revised to address NRC RAI comments.

App. B marked in right hand margin of pages U Structural Integrity Associates, Inc.

Table of Contents Section Page 1.0 INTR OD U C TIO N .......................................................................................................... 1-1 2.0

SUMMARY

OF EXISTING LBB EVALUATION .................................................... 2-1 3.0 QUALIFICATION OF WELD OVERLAID PIPING FOR LBB ............................. 3-1 3.1 Thickness Considerations ............................................................................................ 3-1 3.2 Mitigation of PW SCC Crack Initiation ........................................................................ 3-3 3.3 Crack Growth Considerations ...................................................................................... 3-6 3.4 Inspection Considerations ............................................................................................ 3-8 4.0 LBB EVALUATION DESIGN INPUTS ..................................................................... 4-1 4.1 G eom etry ...................................................................................................................... 4-1 4.2 Loads ............................................................................................................................ 4-2 4.3 Material Properties ....................................................................................................... 4-3 4.3.1 Ramberg OsgoodParametersBased on ASMI1E Code Minimum Values ................. 4-3 4.3.2 J-T Curvefor FerriticMaterialsfrom B& W Report ............................................... 4-3 4.3.3 CASS MaterialProperties........................................................................................ 4-4 5.0 CRITICAL FLAW SIZE EVALUATION .................................................................. 5-1 5.1 M ethodology ................................................................................................................ 5-1 5.2 Z-Factor ........................................................................................................................ 5-1 5.3 Critical Flaw Size ......................................................................................................... 5-3 5.4 Critical Flaw Size Comparison to O riginal Evaluation ............................................... 5-3 6.0 LEAKA G E EV A LUA TION ......................................................................................... 6-1 6.1 M ethodology ................................................................................................................ 6-1 6.2 Leakage Evaluation ...................................................................................................... 6-1 6.3 Results .......................................................................................................................... 6-3 6.4 Leakage Comparison to Original Evaluation ............................................................... 6-3 7.0 C O N CLU SIO N S ............................................................................................................ 7-1 8.0 REFEREN CES ............................................................................................................... 8-1 APPENDIX A CRITICAL FLAW SIZE EVALUATION METHODOLOGY ............. A-1 A .1 IN TROD U C TION ......................................................................................................... A -2 A .2 TEC HN ICA L APPR O A CH ......................................................................................... A -2 A.2.1 Net Section Collapse Model for Cracked Pipe with Weld Overlays ............................ A-2 A .2.2 M ethodology ................................................................................................................. A-3 A .3 RE FEREN CES .............................................................................................................. A -6 Report No. 0800368.404 iii f StructuralIntegrityAssociates, Inc.

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APPENDIX B LEAKAGE EVALUATION METHODOLOGY ................................... B-1 B.1 LBB METHODOLOGY .............................................................................................. B-2 B.2 MORPHOLOGY EFFECTS ON LEAKAGE EVALUATION ................................ B-2 B.3 EFFECT OF CRACK FACE PRESSURE ON LEAKAGE ...................................... B-6 B.3.1 Method for Evaluation U sing PICEP ........................................................................... B-7 B.4 REFEREN CES ............................................................................................................... B-8 APPENDIX C DETERMINATION OF RAMBERG-OSGOOD PARAMETERS ..... C-1 C.1 INTRODUCTION ......................................................................................................... C-2 C.2 M ETH ODOLO GY ....................................................................................................... C-2 C.3 ADJUSTMENT METHODOLOGY ........................................................................... C-3 C.3 R EFEREN CES .............................................................................................................. C-4 Report No. 0800368.404 iv k StructuralIntegrityAssociates, Inc.

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List of Tables Table Page T able 3-1: C rack G rowth R esults ............................................................................................. 3-12 T able 4 -1. G eom etry ................................................................................................................... 4 -6 Table 4-2. Loads at W eld Locations ........................................................................................... 4-6 Table 4-3. ASME Code Strength for Nozzle/Piping at Normal O perating Temperature (556°F) .......................................................................................... 4-7 Table 4-4. Ramberg-O sgood Param eters .................................................................................... 4-7 Table 4-5. Selected J-T Points for Ferritic Base Metal from B&W LBB Evaluation ................ 4-8 Table 4-6. Lower Bound Fracture Toughness of Pump Casings Considering Thermal E mbrittlem ent ...................................................................................................................... 4 -9 Table 4-7. Lower Bound J-T Curve Based on Davis-Besse Pump Materials ........................... 4-10 Table 5-1. Z-factors for Base Metals and Welds at DMW Location .......................................... 5-5 Table 5-2. Critical Flaw Size R esults ......................................................................................... 5-5 Table 6-1: ASME Code Minimum Ramberg-Osgood Parameters ............................................. 6-6 Table 6-2: Leakage Flaw Size for 10 gpm Leak Rate ................................................................ 6-6 Table 6-3: Leak Rate for Leakage Flaw Size Equal to Half Critical Flaw Size ......................... 6-7 Table 6-4: Margin on Flaw Size in Welds and Base Materials .................................................. 6-8 Table 6-5: Leakage Flaw Size Comparison for 10 gpm Leak Rate of the Original B&W Leakage Analysis with The Current Analytical Approach Using PICEP ................. 6-8 Report No. 0800368.404 v StructuralIntegrity Associates, Inc.

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List of Figures Figue Page Figure 3-1. RCP Intlet/Suction Nozzle Model Components .................................................... 3-13 Figure 3-2. RCP Outlet/Discharge Nozzle Model Components ............................................... 3-14 Figure 3-3. RCP Inlet Nozzle ID Surface Axial Residual Stress .............................................. 3-15 Figure 3-4. RCP Inlet Nozzle ID Surface Hoop Residual Stress .............................................. 3-16 Figure 3-5. RCP Inlet Nozzle Post Weld Overlay Axial Stress at 556'F and 2255 psig ......... 3-17 Figure 3-6. RCP Inlet Nozzle Post Weld Overlay Hoop Stress at 556°F and 2255 psig ......... 3-18 Figure 3-7. RCP Outlet Nozzle ID Surface Axial Residual Stress ........................................... 3-19 Figure 3-8. RCP Outlet Nozzle ID Surface Hoop Residual Stress ........................................... 3-20 Figure 3-9. RCP Outlet Nozzle Post Weld Overlay Axial Stress at 5"56°F and 2255 psig ....... 3-21 Figure 3-10. RCP Outlet Nozzle Post Weld Overlay Hoop Stress at 556TF and 2255 psig ..... 3-22 Figure 3-11. RCP Inlet Nozzle K-vs-Flaw Depth at Normal Steady State O perating C onditions ......................................................................................................... 3-23 Figure 3-12. RCP Outlet Nozzle K-vs-Flaw Depth at Normal Steady State O perating C onditions ......................................................................................................... 3-24 Figure 3-13. Preservice and Inservice Inspection Requirements for FSWOLs ........................ 3-25 Figure 4-1. Schematic Diagrams of RCP Nozzle Weld Overlay Design ................................. 4-11 Figure 4-2. J-T Curve for Ferritic Base Metal from B&W LBB Evaluation ............................ 4-11 Figure 4-3. Stress Strain Curves for All RCP CASS Heats ...................................................... 4-12 Figure 4-4. J-T Curve Determ ination ........................................................................................ 4-12 Figure A-1. Schematics of a Circumferentially Cracked Section with Weld Overlay .............. A-7 Report No. 0800368.404 vi j StructuralIntegrityAssociates, Inc.

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List of Abbreviations ANSYS finite element software package for structural analysis ASME Section XI American Society of Mechanical Engineers Boiler and Pressure Vessel Code,Section XI.

B&W Babcock & Wilcox BWR boiling water reactor DBE Design Basis Earthquake DMW Dissimilar Metal Weld EPFM Elastic-Plastic Fracture Mechanics GDC-4 General Design Criteria 4 E modulus of elasticity ft foot 0

F Degrees Fahrenheit gpm gallons per minute GTAW Gas Tungsten Arc Welding ID Inside Diameter IWB One of the subsections of the ASME Code,Section XI J J-integral for fracture toughness Jlc/Klc Fracture Toughness ratio JR J-Integral resistance curves for stable crack growth J-T J-tearing analysis Kips 1,000 pounds ksi 1,000 pounds per square inch MRP Material Reliability Program NUREG U. S. Nuclear Regulatory Commission Regulation NRC/CR Nuclear Regulatory Commission Contractor Report PDI Performance Demonstration Initiative PICEP Pipe Crack Evaluation Program developed by EPRI for measuring leakage psi pounds per square inch psia psi plus atmospheric pressure (absolute pressure)

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PWOL pre-emptive weld overlay RCP Reactor Coolant Pump RCS Reactor Coolant System SQUIRT NRC sponsored evaluation program for measuring leakage SRP 3.6.3 U.S. Nuclear Regulatory Commission (NRC) Standard Review Plan 3.6.3, Revision 1, March 2007 SE safe end SSE Safe Shutdown Earthquake Z-Factor term to describe lower toughness materials used in net-section collapse methodology 10CFR50.55a Title 10, Code of Federal Regulations, Part 50.55a Report No. 0800368.404 viii Revision: 1 V Structural Integrity Associates, Inc.

1.0 INTRODUCTION

A Leak-Before-Break (LBB) evaluation for the main reactor coolant system (RCS) piping for the B&W owners group (B&WOG) plants is documented in Reference 1. A bounding evaluation was provided that included the 28-inch nominal ID reactor coolant pump (RCP) suction and discharge nozzles. The LBB evaluation was performed prior to the NRC issuance of SRP 3.6.3 [2a]. At the time of that evaluation, it was not recognized that the Alloy 82/182 welds connecting the cast stainless steel suction nozzle to the carbon steel elbow and, the discharge nozzle stainless steel safe end to the carbon steel elbow were susceptible to primary water stress corrosion cracking (PWSCC).

One of the limitations imposed by the NRC in SRP 3.6.3 and NUREG-1061, Vol.3 [3] is that locations on piping systems that are susceptible to corrosion mechanisms such as PWSCC do not qualify for application of LBB. In a more recent revision of SRP 3.6.3 [2b], it is stated that non-conforming piping that has been treated by two mitigation methods may qualify for LBB if the piping contains no flaws larger than those permitted by ASME Section XT without repair.

FirstEnergy Nuclear Operating Company (FENOC) is planning on implementing weld overlay repairs on the Alloy 82/182 RCP suction and discharge dissimilar metal welds at Davis-Besse to mitigate PWSCC at these welds. Both full structural and optimized weld overlays are being considered for the discharge nozzle, whereas only the full structural weld overlay option is being considered for the suction nozzle. The application of the overlay with Alloy 52M weld metal provides a PWSCC resistant barrier and also results in substantially reduced stresses on the inner portion of the configuration thereby providing further protection against PWSCC initiation.

Thus, the application of the weld overlay provides two mitigation methods in addition to providing a smooth surface that can enhance future non-destructive examination (NDE).

The application of the weld overlay changes the geometric configuration of the component and as such, the existing LBB evaluation is being updated to reflect the new configuration. The objective of this report is to summarize evaluations of the LBB aspects of installing a weld overlay at the RCS suction and discharge nozzles at Davis-Besse and to show that LBB margins Report No. 0800368.404 1-1

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are still maintained. The overall approach adopted in this report to show that the weld overlay locations on the RCS suction/discharge nozzles at Davis-Besse meet the requirements stipulated in SRP 3.6.3 and NUREG-1061, Vol. 3 is as follows:

• Review the methodology and margins in the existing LBB submittal (Section 2.0)

• Address the effectiveness of PWSCC mitigation by application of the weld overlay and demonstrate that the post weld overlay crack growth (both PWSCC and fatigue) is very minimal for balance of plant life. Also the post weld overlay inspections that will be performed to maintain the integrity of the repair will be addressed (Section 3.0).

• Determine critical through-wall flaw sizes with the application of the weld overlay at the dissimilar metal welds (Section 4.0).

• Determine leakage through half the critical flaw sizes and show that the leakage is greater than the detectable leakage (lgpm) with a factor of 10. The PWSCC morphology for the existing nickel alloy welds will be considered in the determination of the leakage (Section 5.0).

• Provide conclusions of the evaluations (Section 6.0) and references used in the report (Section 7.0).

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2.0

SUMMARY

OF EXISTING LBB EVALUATION The application of LBB evaluation as a method for meeting the requirements of GDC 4 was reviewed by the NRC staff who, in a letter dated February 18, 1986, concluded that an acceptable technical basis had been provided to eliminate, as a design basis, the dynamic effects of large ruptures in the main loop piping of those B&W Owners Group listed facilities which included the Davis-Besse Nuclear Power Station Unit 1 [4]. The GDC-4 criteria were modified in April, 1986 and October, 1987 which removed the need for an exemption. Davis-Besse implemented LBB in 1990, by letter to the NRC dated November 6, 1990 (Serial Number 1849)

[5].

At the time of approval, it was not recognized that the RCP dissimilar welds were susceptible to PWSCC. Requirements in NUREG/CR1061, Vol. 3 [3], required that the use of LBB in areas where susceptible material is present would require mitigating measures and NRC review/

approval. SRP 3.6.3, Rev. 1 states that piping systems that are susceptible to active stress corrosion cracking mechanisms may qualify for application of LBB evaluation if treated with two mitigation methods and the piping contains no flaws larger than those permitted by ASME Section XI without repair.

The original Babcock and Wilcox Owners Group (BWOG) LBB evaluation [1] was performed generically for all of the B&W-designed plants. It considered bounding material properties and loads for the main RCS piping for all B&W-designed plants. The 28-inch nominal ID cold leg, representative of the reactor coolant pump inlet and outlet piping, was determined to be the critical piping section for the RCS piping in the original LBB evaluation. The LBB evaluation for 28" straight pipe and elbow of Davis-Besse from the B&W report [1] is summarized in the following paragraphs.

The leakage evaluation was conducted for 2150 psi (assumed to be 2150 psia) and 600'F [1, Pages 3-9 and 4-1 ] with two sets of conditions for the 28-inch piping:

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• For the 28-inch straight pipe (SA-106 Grade C, with yield strength of 29,600 psi, E =

26,500 ksi, unclad ID 28.5 inches and thickness of 2.375 inches [1, Table 3-6], three loading cases were evaluated [1, Table 4-1]:

Moment = 560 ft-kips 10 gpm Flaw Length = 9.2 inches Moment = 1095 ft-kips 10 gpm Flaw Length = 7.9 inches Moment = 1246 ft-kips 10 gpm Flaw Length = 7.7 inches For the 28-inch elbow (SA-516 Grade 70, with yield strength of 28,100 psi, E = 26,500 ksi, unclad ID 28.5 inches and thickness of 3.125 inches [1, Table 3-6], three load cases were evaluated [1, Table 4-1]:

Moment = 871 ft-kips 10 gpm Flaw Length = 9.6 inches Moment = 1246 ft-kips 10 gpm Flaw Length = 9.0 inches Moment = 1278 ft-kips 10 gpm Flaw Length = 9.Oinches The critical flaw size evaluation was conducted using elastic plastic fracture mechanics (EPFM -

EPRI/GE methods) for calculating the J-integral for moment loading [1, Section 4.5.3] using only an equivalent moment. The loads and base flaw sizes for the fracture mechanics analysis are as follows for the 28-inch pipe [1, Table 4-6]:

Flaw Size, Flaw Angle, Axial Force *

(excluding Moment, ft-kips in. degrees pressure), kips 28" ID Pipe 9.2 17.2 250.3 3098.0 28" ID Elbow 9.0 16.5 539.3 2822.8

• Internal pressure was included in the analysis separately.

J-T analysis was conducted to determine the margin on flaw size and reported [1, Table 4-10].

The 2 critical flaw size of the 28" straight pipe is:

o a = 10.18 inches, based on base metal properties o a = 18.54 inches, based on weld metal properties Report No. 0800368.404 2-2  : StructuralIntegrity Associates, Inc.

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Based on these results, it was concluded that the margin on 10 for leakage and the margin on flaw size of 2 was met, such that all B&W-designed plants qualified for LBB. No evaluations were included based on the specific loading conditions for Davis-Besse.

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3.0 QUALIFICATION OF WELD OVERLAID PIPING FOR LBB The technical basis for weld overlays is presented in MRP-169 [6]. The purpose of the MRP-169 report is to define methodology and criteria for the use of pre-emptive weld overlays (PWOLs) as a mitigation measure for PWSCC in PWR primary coolant pipe and nozzle welds. MRP-169 documents these criteria, and presents examples of their application. Key elements of MRP-169 are discussed in the following sections.

3.1 Thickness Considerations In the application of a weld overlay in a plant, the weld overlay thickness may vary significantly.

In addition to allowable tolerances, the overlay may be full structural (taking credit for none of the underlying base material) resulting in a relatively thick overlay or it may be optimized (taking credit for a portion of the underlying base material). For the evaluation presented for Davis-Besse Unit 1, both full structural and optimized weld overlays are being considered for the discharge nozzle, whereas only the full structural weld overlay option is being considered for the suction nozzle. A range of thickness is considered between the minimum required for structural purposes to the maximum allowed as governed by inspection requirements. The range is considered to show that the weld overlay thickness does not significantly change the conclusions related to LBB.

The fundamental assumption of structural weld overlay sizing is that a crack is present in the original pipe or nozzle weld, which must be evaluated in accordance with ASME Section XI flaw evaluation rules [7, 8]. These rules establish an end-of-evaluation-period allowable flaw size based on the maximum size flaw that can be sustained in the component without violating original design margins (typically ASME Section III for primary system components).

A full structural weld overlay (FSWOL) is designed under the assumption that the base material is completely cracked. In the case of low applied loads at the overlay location, the ASME Section XI flaw depth limit of 75% of the wall thickness controls the weld overlay thickness (equivalent to one-third of the base metal thickness). In the case of higher applied loads, additional thickness Report No. 0800368.404 3-1 StructuralIntegrity Associates, Inc.

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may be required. Based on inspection requirements and the actual field application, the actual thickness may be somewhat greater.

Weld overlay sizing requirements are further defined in Code Cases N-504-3 and N-740-2 [9, 10]

for FSWOLs. These overlays may be used for any application in which cracking has been detected in a weld consisting of a combination of a nozzle, pipe or safe-end. ASME Code Section XI allowable flaw size criteria (IWB-3640 and Appendix C) are used for sizing the weld overlay, based on the assumption that a circumferential crack is present completely through-wall and 3600 around the circumference of the original base material.

An "optimized" structural weld overlay is an acceptable alternative to full structural overlays when there are no flaws present in the weld or any observed flaws are limited in size. For an optimized weld overlay (OWOL), the design basis flaw assumption is still 360' around the weld, but with a depth equal to 75% of the original pipe wall.

The OWOL flaw size assumption is a reasonable and conservative design basis for preemptive weld overlays, since:

1 - The pipe will have been inspected immediately prior to the overlay application, using an inspection technique qualified in accordance with ASME Section XI, Appendix VIII [8]

and found to exhibit no evidence of cracking greater than 50% of the wall thickness in the original weld.

2 - Post-overlay ultrasonic examinations (and future inservice inspections) will be required to verify the integrity of the applied weld overlay, and the examination volume for these inspections is increased to include the weld overlay plus the outer 50% of the original pipe wall (see Section 3.4 - Inspectability Considerations).

If a flaw (embedded or inside-surface-connected) is identified during an inspection it would be characterized per ASME IWA-3300 and evaluated per the acceptance standards of ASME IWB-3500.

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The following considerations will be applied to determine if an optimized weld overlay may be applied or if a full structural weld overlay must be utilized:

• Axial or circumferential flaws located entirely within the inner 50 percent of the original dissimilar metal weld wall thickness may be repaired with an OWOL.

• Axial flaws that do not extend into the outer 25 percent will be evaluated for repair with an OWOL.

• Axial flaws that extend into the outer 25 percent of the original dissimilar metal weld wall thickness must be repaired with an FSWOL.

• Circumferential flaws that extend into the outer 50 percent of the original dissimilar metal wall thickness must be repaired with an FSWOL.

Since the design basis flaw depth assumption for OWOL sizing that is 75% of the original wall thickness, the assumed flaw already meets the general ASME Code Section XI 75% criterion without an overlay. Thus, the resulting OWOL thickness will not be controlled by this somewhat arbitrary limit, but will instead be based on the actual internal pressure and pipe loads at the location of the DMW being overlaid and the ASME Code Section XI allowable flaw size criteria (IWB-3640 and Appendix C).

3.2 Mitigation of PWSCC Crack Initiation The application of a weld overlay produces considerable compressive stresses in the material beneath the weld overlay due to the shrinkage of the weld overlay material during its installation.

A key aspect of the weld overlay design process is to demonstrate that favorable residual stress reversal occurs such that PWSCC initiation and growth is mitigated. Extensive analytical and experimental work was performed on weld-overlaid BWR pipe-to-pipe welds of various pipe sizes to demonstrate that favorable residual stresses result for full-structural weld overlays [11, 12]. A recent PWOL test program [6] also demonstrated that measured residual stresses in a typical PWR mid-sized DMW weld overlay were highly favorable when applied to a weld with a severe inside surface repair.

For application of weld overlays in PWR plants, a joint specific, overlay specific weld residual stress analysis is required for each unique PWOL configuration in which there is a significant Report No. 0800368.404 3-3 Structural Integrity Associates, Inc.

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geometry, material, or welding process difference from a previously analyzed overlay (beyond standard drawing/fabrication tolerances). These must be performed with analysis methods and tools that are appropriate for this type of analysis, including transient thermal analysis capability, non-linear elastic-plastic modeling capability, and temperature dependent material properties.

Several such tools exist and have been demonstrated to produce residual stress results that are in agreement with (or conservatively bound) experimental measurements. The residual stress analysis considers actual welding parameters to be used in applying the weld overlay, including bead sequence, welding direction, heat input, thermal boundary conditions (wet or dry) and inter-pass temperature limits.

The initial residual stress condition of the DMW joint has a significant bearing on its susceptibility to PWSCC, especially as influenced by in-process repairs performed during plant construction. In fact, in essentially all cases in which PWSCC has been discovered in PWR butt welds, evidence of significant in-process repairs during construction has been found. Thus, to adequately demonstrate the favorable residual stress effects of a weld overlay, one must start with a highly unfavorable, pre-overlay residual stress condition such as that which would result from an ID surface weld repair during construction. If the nozzle-specific weld overlay design is shown to produce favorable residual stresses in this severe case, one can be assured that it will effectively mitigate against future PWSCC in the DMW.

Acceptable residual stresses for purposes of satisfying this requirement are those which, after application of the weld overlay, are substantially reduced on the inner portion of the weld, over the entire length of PWSCC susceptible material on the inside surface, at operating temperature, but prior to applying operating pressure and loads. After application of operating pressure and loads, the resulting stresses must be compressive or small enough to ensure a low probability of initiating new PWSCC cracks and to limit the potential of significant crack propagation in the weld..

The above combination of residual stress and crack growth criteria, in conjunction with required post-overlay inspections, provides protection against initiating new PWSCC cracks after application of the weld overlay and/or propagation of pre-existing cracks that would violate the overlay design basis.

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Specific analyses were performed for the RCP cold leg inlet and outlet nozzle dissimilar metal welds (DMW) at Davis-Besse Unit 1 to determine the residual stress distribution after the application of the weld overlays (OWOL and FSWOL). For each of the configurations, the analysis included simulation of a weld repair from the inner diameter surface (ID) for a postulated flaw within the original nozzle-to-safe end DMW. The ID weld repair was simulated to provide an unfavorable stress condition (prior to applying the weld overlay) due to the original fabrication of this weld. The as-analyzed weld overlay repair corresponds to the minimum OWOL and FSWOL design dimensions and thus is considered to be conservative with respect to prediction of minimum compressive stresses in the underlying base material. The minimum OWOL design dimensions were used for the residual stress analyses shown in Figure 3 through Figure 3-10. Typically, the weld overlay will be slightly longer and thicker upon installation, providing more compression under the overlay. The analyses were performed using finite element models developed using the ANSYS software package [13]. Figures 3-1 and 3-2 depict the components included in the finite element models of the suction and discharge nozzle assemblies, respectively. The analytical process closely simulated the history of operation of this weld, as follows:

• Simulation of ID weld repair

• Ambient conditions

• Application of weld overlay

" Normal operating conditions The results of the finite element analyses are summarized in Figures 3-3 to 3-6 for the RCP inlet nozzle that uses minimum OWOL design dimensions. Figures 3-3 and 3-4 show the inside axial and hoop surface stresses through the various phases of the simulation of the weld overlay on the inlet nozzle. It can be seen that after the ID weld repair, very high tensile stresses are generated at the inside surface of the DMW. After application of the weld overlay followed by normal operating conditions, the residual stresses are reduced. Figures 3-5 and 3-6 show the through thickness stress distributions after application of the weld overlay followed by normal operating conditions in both the axial and hoop directions. It can be seen that compressive stresses exist through a significant portion of the thickness, demonstrating the effectiveness of the weld overlay Report No. 0800368.404 3-5 j StructuralIntegrity Associates, Inc.

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to significantly reduce the tensile stresses or convert them to compressive stresses and thereby, mitigating PWSCC.

Similarly, the results of the finite element analyses are summarized in Figures 3-7 to 3-10 for the RCP outlet nozzle that uses minimum OWOL design dimensions. Figures 3-7 and 3-8 show the inside axial and hoop surface stresses through the various phases of the simulation. It can be seen that after the ID weld repair, the inside surface of the DMW is very tensile in the hoop direction but less tensile in the axial direction. After application of the weld overlay followed by normal operating conditions, the inside surface residual stresses have decreased to almost zero in the axial direction and nearly all compressive in the hoop directions. Figures 3-9 and 3-10 show the through thickness stress distributions after application of the weld overlay followed by normal operating conditions in both the axial and hoop direction. It can be seen that the compressive stresses penetrate through a significant portion of the thickness, demonstrating the effectiveness of the weld overlay to significantly reduce the tensile stresses or convert them to compressive stresses and, thereby mitigating PWSCC.

3.3 Crack Growth Considerations There are two issues that must be addressed relative to crack growth of a DMW location with a weld overlay applied. As part of the design process, evaluations are performed to assure that potential cracking in the Alloy 82/182 material is not significant from the standpoint of both fatigue and PWSCC crack growth mechanisms. In this evaluation, plant design transients are utilized, assuming that the defined number of cycles for 40 years, multiplied by a factor of 1.5 to conservatively define cycles for 60 years of operation, is uniformly distributed over the remaining plant operating life to create a history of plant cycles versus time for the fatigue crack growth analysis.

The prevention of PWSCC growth is achieved by the relatively favorable compressive state of stress discussed previously. Fatigue crack growth is mitigated by consideration of the cyclic loadings on the overlaid location with consideration of the beneficial compressive state of stress, since low mean stresses retard crack growth.

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Specific fatigue crack growth (FCG) and PWSCC crack growth were performed for the Davis-Besse Unit 1 Alloy 82/182 RCP nozzles DMW welds. Representative fracture mechanics models were used to determine stress intensity factors (K). The stress intensity factors for each type of load are computed as a function of postulated crack depth in the DMW and superimposed for the various operating states. All relevant stresses that contribute to fatigue crack growth were considered in the analysis. These stresses result from primary loads such as internal pressure and external piping loads, and secondary loads such as thermal gradient stresses (due to thermal transient events), and weld residual stresses. The through-wall stresses from these loads are extracted and curve fitted to a third order polynomial. FCG (or combined FCG and PWSCC growth, if PWSCC is active) is computed using linear elastic fracture mechanics (LEFM) techniques. PWSCC growth is determined by computing the stress intensity factor versus flaw depth curve (K-vs-a) at steady state normal operating conditions.

Per NUREG/CR-6721 [14] and NUREG/CR-6907 [15], the crack growth law for Alloy 600 weld metals (Alloy 82/Alloy 182) with a multiplier to account for crack growth in a pressurized water reactor (PWR) environment is used in the evaluation. For the minimum thickness FSWOL design, the time it takes for an initial flaw of 75% of the original base metal thickness to reach 100% of the original base metal is reported.

For PWSCC evaluation for Alloy 82/182, the correlation provided in MRP-1 15 [16] was used.

The resulting through-wall K distributions at normal operating conditions for the DMW with the minimum FSWOL are shown in Figure 3-11 for the RCP inlet nozzle. The bounding K distributions for both a postulated axial flaw and a postulated circumferential flaw are presented in Figure 3-11. It can be seen that for the case of the axial flaw, the K decreases to nearly zero at about 70% of the wall thickness and still relatively small at 75% of the wall thickness. For the case of a postulated circumferential flaw, the K is positive throughout the wall thickness, decreasing to about29 ksiqin at 75% of the original wall thickness.

Report No. 0800368.404 3-7 Structural Integrity Associates, Inc.

Revision: 1

For the RCP outlet nozzle, the resulting through-wall K distributions at normal operating conditions for the DMW with the minimum OWOL are shown in Figure 3-12. The K distributions for both a postulated axial flaw and a postulated circumferential flaw are shown. It can be seen that for the case of the axial flaw, the K is negative from about 30% up to approximately 90% of the wall thickness indicating no PWSCC after the overlay application.

For the case of a postulated circumferential flaw the K is positive but mostly below 25 ksi4in beyond 50% of the wall thickness.

The bounding fatigue crack growth results for the RCP inlet and outlet nozzles are shown in Table 3-1. For the FSWOL design on the DMW of the RCP inlet nozzle, it would take greater than 16 years for an initial circumferential flaw of 75% of the original base metal thickness at the analyzed section to reach 100% of the original base metal thickness. The equivalent time for an axial flaw is 14 years. At the DMW of the RCP outlet nozzle, it would take greater than 30 years for an initial axial flaw of 75% of the original base metal thickness at the analyzed section to reach 100% of the original base metal thickness for both the OWOL and FSWOL designs. The equivalent time for the circumferential flaw is 12 years and 26 years for the OWOL and FSWOL designs, respectively.

Since the weld must be inspected every 10 years, this provides adequate margin to assure that a crack will not grow beyond 100% of the original base metal thickness between inspections.

3.4 Inspection Considerations Details of the specific inspection requirements for implementation of the weld overlay repairs at Davis-Besse Unit 1 are provided in FENOC's Relief Request [ 17]. This section provides a general overview of these requirements.

Examination requirements for weld overlays involve two aspects. One is the type of examination and the other is the required interval. The requirements for the type of examinations for weld overlays are defined in ASME Code Case N-504-3 and N-740-2 [9, 10]. They are summarized in Figure 3-8.

These requirements are consistent with current PDI techniques [18] and were originally developed for weld overlay repairs of IGSCC in BWR stainless steel welds, where the initiating flaws are Report No.1 0800368.404 3-8 Structural Integrity Associates, Inc.

Revision:

fully characterized with respect to length and depth. Since the full structural weld overlay design for these repairs assumes that the original flaw is through the original pipe wall, evaluation of the outer 25% of the original pipe wall along with the weld overlay is considered conservative for pre-service and subsequent inservice examinations, in that it provides some advance warning if the flaw were to unexpectedly propagate. For optimized overlays, where the weld overlay design assumes the existence of a flaw 75% through the original wall thickness, it is desired to provide a similar "advance warning" examination volume for the unlikely event that a flaw would initiate and begin propagating after application of the PWOL. For this design assumption, the examination coverage for weld overlay preservice inspections and subsequent inservice inspections is increased to include the thickness of the weld overlay plus the outer 50% of the original pipe wall thickness. This will provide additional margin to account for the uncertainty regarding the pre-weld overlay status of the original weld and is well within current ultrasonic examination capabilities.

Weld overlays examinations must conform to the rules in the ASME Code,Section XI for welds in piping that require the procedures, equipment, and personnel to be qualified by a performance demonstration in accordance with Appendix VIII, as amended in 10CFR50.55a [19]. Currently, the utilities use the PDI qualification process [18] to satisfy these requirements. Procedures, equipment, and personnel used for examination of preemptive weld overlays shall be qualified in accordance with these rules [8, 9, 10].

The inspection interval and sample size for IGSCC mitigating weld overlays in BWVR weldments are defined in NUREG-0313 [20]. NUREG-0313 defines examination requirements in terms of the category of IGSCC susceptible weldment. The categories of weldments are based on 1) the IGSCC resistance of the materials in the original weldment, 2) whether or not stress improvement (or overlay) has been performed on the original weldment, 3) whether or not a post stress improvement UT examination has been performed, 4) the existence (or not) of cracking in the original weldment, and 5) the likelihood of undetected cracking in the original weldment prior to the application of the overlay. The categories range from A through G, with the higher letter categories requiring augmented inspection intervals and/or sample size. Category A is the lowest Report No. 0800368.404 3-9 V StructuralIntegrity Associates, Inc.

Revision: 1

category, consisting of piping that has been replaced (or originally fabricated) with IGSCC resistant material.

Recently issued MRP Primary System Piping Butt Welds Inspection and Evaluation Guidelines (MRP-139) [21] utilize a similar classification scheme. Specifically, in accordance with MRP-139, PWSCC susceptible weldments with no known cracks (based on examination) that have been reinforced by a full structural weld overlay made of PWSCC resistant material are designated Category B. PWSCC susceptible weldments that contain known cracks that have been repaired by a full structural weld overlay are designated Category F.

For PWOL applications, the absence of cracking in the original weldment, the structural reinforcement and resistant material supplied by the overlay, the residual stress improvement provided by the PWOL, and the requirement to do a PDI qualified examination immediately following application of the PWOL are deemed to be consistent with a low letter ranking (Category B) for either full structural or optimized structural overlays. Therefore the following requirements for subsequent inservice inspections shall be satisfied:

1. For PWSCC susceptible weldments for which an inservice inspection is performed in accordance with ASME Code,Section XI, Appendix VIII, Supplement 10 [8] immediately prior to application of the PWOL, and such inservice inspection demonstrates the weld to be absent of any flaws or crack-like indications, future ISI of the welds shall be performed in accordance with current ASME Section XI Code requirements. This requirement is consistent with MRP-139 Category B, except that it is independent of whether the PWOL is a full structural or optimized structural overlay.

2. For PWSCC susceptible weldments for which an inservice inspection in accordance with ASME Code,Section XI, Appendix VIII, Supplement 10 [8] is not performed immediately prior to application of the PWOL, or in which flaws or crack-like indications are detected, the weldment must be assumed to be cracked. FirstEnergy has committed in RR-A-32 and RR-A-33 that for pre-existing flaws, an in-service examination volume shall be ultrasonically examined once during the first or second refueling outage following the Report No. 0800368.404 3-10 StructuralIntegrityAssociates, Inc.

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application of the overlay. For OWOL, examination volumes that show no indication of crack growth or new cracking shall be placed into a population to be examined once in a ten-year inspection interval. Whereas, for FSWOL, examination volumes that show no indication of crack growth or new cracking shall be placed into a population of full structural weld overlays to be examined on a sample basis. Twenty-five (25) percent of this population shall be added to the ISI Program in accordance with ASME Section XI, IWB-2412(b). If no new indications are seen or if no growth of existing indications is observed in the examination volume, the inspection interval shall revert to the existing ASME Code program. (Note: the assumption is that weld overlay repairs applied to this category will be full structural, not optimized structural.)

Details of the inspections that will be performed as part of the weld overlay implementation at Davis-Besse Unit 1 are provided in FENOC's Relief Request [ 17] and are consistent with those described above.

Report No. 0800368.404 3-11 C StructuralIntegrity Associates, Inc.

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Table 3-1: Crack Growth Results Time to Reach 75% or 100% of Original Base Metal Thickness (1,4)

Flaw (1) Inlet Nozzle Outlet nozzle FSWOL OWOL FSWOL 3

>30 years(3) >30 years( )

Axial >14 years (3)

Circumferential > 16 years(3 ) 12 years(2) 26 years(3)

Notes:

(1) The initial flaw is postulated to grow to 75% of the original wall thickness for the OWOL and 100% of the original wall thickness for the FSWOL.

(2) Initial flaw depth = 50% of original base metal thickness at the DMW section analyzed = 1.45".

(3) Initial flaw depth = 75% of original base metal thickness at the DMW sections analyzed

= 2.325" and 2.175" for the RCP inlet and outlet nozzles, respectively.

(4) Results are conservatively based on air backed WOL application.

Report No. 0800368.404 3-12 StructuralIntegrity Associates, Inc.

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Weld overlay-,,

ELEMENTS MAT NUM Elbow Cladding DM Weld Butter Dissimilar Metal Weld Piping Elbow Inlet Nozzle Forging RCP Inlet Nozzle (Minixm Overlay Dimensions)

Figure 3-1. RCP Inlet/Suction Nozzle Model Components Report No. 0800368.404 3-13 Revision: 1 V Structural Integrity Associates, Inc.

Dissimilar Metal Weld ANr, Stainless Steel Butt Weld

\ Weld overlay DM Weld Butter Figure 3-2. RCP Outlet/Discharge Nozzle Model Components Report No. 0800368.404 3-14 C Structural IntegrityAssociates, Inc.

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ID Surface Axial Residual Stress s Post ID weld repair 70':F i Post weld overlay 70'F -E Post weld overlay 556TF/2255 psig 120 100 80

. 60

'40 20 0

-4 -3 -2 -1 0 1 2 3 5 6

-20

-40 Distance from ID Weld Repair Centerline (in)

Note: Results obtained using minimum OWOL design dimensions.

Figure 3-3. RCP Inlet Nozzle ID Surface Axial Residual Stress Report No. 0800368.404 3-15 Revision: 1 C StructuralIntegrity Associates, Inc.

ID Surface Hoop Residual Stress sPost ID weld repair 70'T' Post weld overlay 70':*-F - Post weld overlay 556:'F/2255 psig 120 100 80 60 40 20 0

-20 -5:~:~

-40 Distance from ID Weld Repair Centerline (in)

Note: Results obtained using minimum OWOL design dimensions.

Figure 3-4. RCP Inlet Nozzle ID Surface Hoop Residual Stress Report No. 0800368.404 3-16 Revision: 1 V StructuralIntegrity Associates, Inc.

1 NODAL SOLUTION STEP=7030 SUB =2 TIME=758 SY (AVG)

TOP RSYS=0 DMX =.148419 SMN =-53503 SMX =95720

-53503 -20342 12818 45979 79139

-36923 -3762 29399 62559 95720 Notes: (a) The units of the color bar across the bottom of the figure are psi.

(b) Results obtained using minimum OWOL design dimensions.

Figure 3-5. RCP Inlet Nozzle Post Weld Overlay Axial Stress at 556°F and 2255 psig Report No. 0800368.404 3-17 V Structural Integrity Associates, Inc.

Revision: I

NODAL SOLUTION STEP=7030 SUB =2 TIME=758 SZ (AVG)

TOP RSYS=O DMX =.148419 SMN =-42551 SMX =109392

-42551 -8786 24979 58744 92509

-25669 8096 41861 75627 109392 Notes: (a) The units of the color bar across the bottom of the figure are psi.

(b) Results obtained using minimum OWOL design dimensions.

Figure 3-6. RCP Inlet Nozzle Post Weld Overlay Hoop Stress at 5561F and 2255 psig Report No. 0800368.404 3-18 StructuralIntegrity Associates, Inc.

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ID Surface Axial Residual Stress

• Post IDweld repair 70'-'F *Post weld overlay 70"'F

-- Post weld overl ay 556':*F/2255 psi g 100 80 60 PO 40

20 V,)

0

=,20- -4 -3 -2 -1 0 1 2 3 1

-40

-60 DMW

-80 Distance from ID Weld Repair Centerline (in)

Note: Results obtained using minimum OWOL design dimensions.

Figure 3-7. RCP Outlet Nozzle ID Surface Axial Residual Stress Report No. 0800368.404 3-19 V StructuralIntegrity Associates, Inc.

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ID Surface Hoop Residual Stress

--- Post ID weld repair 70'F - Post weld overlay 70'F

-- Post weld overlay 556:'F12255 psig 140 120 100 80

-.60

'P40 P20

(.*o

• 2o

-40

-60

-80

-100 Distance from ID Weld Repair Centerline (in)

Note: Results obtained using minimum OWOL design dimensions. I Figure 3-8. RCP Outlet Nozzle ID Surface Hoop Residual Stress Report No. 0800368.404 3-20 S

StructuralIntegrity Associates, Inc.

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1 NODAL SOLUTION STEP=2538 SUB =2 TIME=962 SY (AVG)

RSYS=0 DMX =.276481 SMN =-56238 SMX =120657

-56238 -16928 22382 61692 101002

-36583 2727 42037 81347 120657 Residual stress analysis Notes: (a) The units of the color bar across the bottom of the figure are psi.

(b) Results obtained using minimum OWOL design dimensions.

Figure 3-9. RCP Outlet Nozzle Post Weld Overlay Axial Stress at 5561F and 2255 psig Report No. 0800368.404 3-21 C StructuralIntegrity Associates, Inc.

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I NODAL SOLUTION STEP=2538 SUB =2 TIME=962 SZ (AVG)

RSYS=0 DMX =.276481 SMN =-48607 SMX =143601

-48607 5894 36819 79532 122245

-27251 15462 58175 100888 143601 Residual stress analysis Notes: (a) The units of the color bar across the bottom of the figure are psi.

(b) Results obtained using minimum OWOL design dimensions.

Figure 3-10. RCP Outlet Nozzle Post Weld Overlay Hoop Stress at 5561F and 2255 psig Report No. 0800368.404 3-22 V StructuralIntegrityAssociates, Inc.

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Axial Flaw 100 U')

80 60 0

U-40 co) 2 I (D

0 0 0.5 1 1.5 2 12,5 3 3,5

-20 Flaw Depth, Inches Circumferential Flaw 70 60 50 0

40 CU 30 U- 20 10 0

0.5 1 1.5 2.5 3 315

-10

-20

-30 --

Flaw Depth, Inches Figure 3-11. RCP Inlet Nozzle K-vs-Flaw Depth at Normal Steady State Operating Conditions Repo rt No. 0800368.404 3-23 W tq~~

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Axial Flaw 50 0

Q 2 3 4 (0

Z C -50 100 Flaw Depth, Circumferential Flaw 01 C>

0~

(VO 40 1-*

LO (V r- MV 0 '1 2 3 4 Flaw Depth, Inches Figure 3-12. RCP Outlet Nozzle K-vs-Flaw Depth at Normal Steady State Operating Conditions Report No. 0800368.404 3-24 V Structural IntegrityAssociates, Inc.

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Preservice and Inservice Examination Volume A-B-C-D Surface: Liquid penetrant examination of overlay material surface.

Volumetric: Overlay directly over original PWSCC susceptible weldment (including nozzle, buttering, DMW and PWSCC susceptible safe-end if present) plus 1/2 inch to either side, to a depth of the outer 25% (FSWOL) or 50% (OWOL) of underlying material (A-B-C-D).

Figure 3-13. Preservice and Inservice Inspection Requirements for FSWOLs Report No. 0800368.404 Revision: 1 3-25 C StructuralIntegrityAssociates, Inc.

4.0 LBB EVALUATION DESIGN INPUTS 4.1 Geometry The weld overlay repair is applied on the dissimilar material weld (DMW) on the suction and discharge nozzles of the RCS only. The material properties and geometry dimensions around the DMW region have been changed while the rest of the RCS piping is not affected. The original LBB evaluation [1] remains valid for the unaffected regions of the reactor coolant piping system.

Hence, only the region related to the DMW with weld overlay repairs need the LBB evaluation presented herein.

Figure 4-1 shows schematic diagrams of the 28" I.D. Outlet/Discharge and Inlet/Suction RCP nozzle weld overlay designs. Since the thicknesses of the DMW and weld overlay are not uniform, LBB evaluation is performed on both sides of the DM weld as well as the base materials adjacent to them which are being considered as possible locations of a through-wall crack. Thus, the following crack paths will be assumed at four locations for each nozzle as illustrated in Figure 4-1:

Path 1. nozzle or safe end Path 2. weld at nozzle or safe end Path 3. weld at elbow Path 4. elbow Since both FSWOL and OWOL are designed for the weld for the two nozzles, the critical flaw size for both of these two designs will be determined. For each design, minimum required and maximum allowable weld overlay thicknesses will be evaluated. Hence, for each location, four different cases will be analyzed. The geometry data for each analysis case is listed in Table 4-1.

Report No. 0800368.404 4-1 Structural Integrity Associates, Inc.

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4.2 Loads The loads utilized in the critical flaw and leakage evaluation are taken from the engineering information record for the RCP suction and discharge nozzles U]. The loads for the suction nozzle are taken at , corresponding to the Alloy 82/182 nozzle-to-piping elbow welds on the two distinct pumps on each loop. For the discharge nozzle, are located at the pump discharge weld between the RCP nozzle and the safe-end, not the Alloy 82/182 weld between the safe-end and the piping elbow. In addition, the loads are in a global coordinate system that is not coincident with the nozzle axial direction [1]. Hence, the bending moments at the DM weld of the discharge nozzle are adjusted to account for the safe end which is 15.875 inches long. In addition, to determine the loads in a coordinate system that is normal and outward from the discharge nozzle, the forces and moments at the nodes are transformed based on the angle relative to the positive global coordinate .

Per the guidance from SRP 3.6.3, the loads to be applied at the LBB locations for leakage evaluations are based on the algebraic sum of the normal operating forces and moments (Dead Weight + Thermal loads), while the loads for critical flaw size evaluations use the sum of absolute values of the normal operation loads and SSE loads. Table 4-2 shows the loads for the for the weld locations. It can be noticed that the loads on both RCP pumps are very similar.

Hence, the loads on Pump 1A1 are used to perform the LBB evaluation as the resulting critical flaw sizes and leak rates are not expected to be significantly affected by the small differences in the loads.

Consistent with the net-section collapse models described in SRP 3.6.3 and in Section XI, Appendix C of the ASME code, crack face pressure is not considered. Also, it should be noted here that the dead weight of the WOL as well as the axial shrinkage due to the application of the WOL are not considered as the effect of these are negligible compared to the existing loads.

Also, the weld residual stresses calculated in Section 3 are not considered as applicable loads since these stresses are localized in nature and are self relieving in the cracked condition assumed for critical flaw and leakage evaluation. This is justified since all welds have residual Report No. 0800368.404 4-2 T StructuralIntegrity Associates, Inc.

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stresses due to weld shrinkage and these are not considered in performing LBB evaluations and they are not considered in SRP 3.6.3.

4.3 Material Properties The materials properties were taken from the ASME Code [23] at the operating temperature of 556'F and shown in Table 4-3.

4.3.1 Ramberg Osgood ParametersBased on ASME Code Minimum Values The Ramberg-Osgood (R-O) relationship is used in elastic-plastic fracture mechanics analysis and in the leakage analysis to describe the stress-strain curve. Appendix C describes the R-O stress strain representation and describes how it may be determined using ASME Code minimum properties. The parameters a and n are determined using the methodology from Reference 24 as described in Appendix C. The Ramberg-Osgood parameters are presented in Table 4-4 for all the materials under consideration.

4.3.2 J-T Curvefor FerriticMaterialsfrom B& WReport Using the JR equations from the B&W LBB evaluation [1], a J-T curve for ferritic material for elbows of both of the suction and discharge nozzles was constructed and used in an EPFM evaluation of the ferritic material for a Z-factor calculation. Using plots of J versus Aa, the tearing modulus T was calculated as T = (E/Sflow2) dJ/da In this evaluation, the values of modulus of elasticity (E) and flow stress (Stlow) as determined from the B&W report [1] were used for calculating the tearing modulus. Since the original B&W report did not extrapolate the curve as allowed by the procedure in NUREG-1061 Volume 3 [3] and SRP 3.6.3 [2], the J was limited to the maximum valid point as in the B&W evaluation.

The resulting curve is shown in Figure 4-2 and selected data points are presented in Table 4-5.

Report No. 0800368.404 4-3 ;2* StructuralIntegrity Associates, Inc.

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In Section 5, elastic-plastic fracture mechanics will be used to verify if Z-factors based on ASME Code Section XI Appendix C could be conservatively used for both the CASS and the ferritic material, Evaluations will be conducted for each material separately in flaw stability calculations using the developed J-T curves.

Since the Alloy 52M would be applied using GTAW process, no J-T analysis needs to be calculated. For the Alloy 82/182 material, alternate sources of information will be used for determination of Z-factors. Using this approach, the J-T curves were not specifically required for determination of critical flaw size.

4.3.3 CASS MaterialProperties The base material for the RCP nozzle is cast austenitic stainless steel (CASS). In a previous Code Case N-481 evaluation for the Davis-Besse reactor coolant pumps [25], actual material properties were used to develop lower bound J-R curves and Jlc/Klc for the pump CASS material heats with consideration of thermal embrittlement. The lower bound saturated fracture toughness of the worst Davis-Besse pump casing considering thermal embrittlement was used.

Table 4-6 shows the toom temperature mechanical properties, compositional information, and various calculated parameters of the CASS. For this evaluation, the important properties are the mechanical properties and the J-R curve that was determined for each of the various CASS heats used in the pump construction. The actual pump mechanical properties shown in Table 4-6 were evaluated to determine R-O parameters for performing fracture mechanics and leakage analysis.

Since the properties were at room temperature, they were adjusted to 5560 by using the ratio between ASME room temperature properties and those at 5560. Using the ASME Code value for modulus of elasticity and the measured elongation, stress strain curves were constructed as shown in Figure 4-3. The minimum curve may be represented by:

- E = 25,520 ksi

-Sy =20.57 ksi

- St = 68.4 ksi

- Sflow = 44.485 ksi

- 0 = Sy/E in/in Report No. 0800368.404 4-4 StructuralIntegrity Associates, Inc.

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a = 2.481 n = 3.313 Evaluations of the J-R curves (J = CAan) as defined in Table 4-5 for all 8 material heats was also undertaken. Based on plots from NUREG/CR-4513 [26], it was assumed that the J-R curves would be valid to 0.4 inches (- 10 mm). This is less than the values used in the B&W report [1],

so is conservative relative to that evaluation. Then, using plots of J versus Aa, the Tearing Modulus T was calculated as T = (E/Sflow2 ) dJ/da In this evaluation, the temperature adjusted average of the yield and ultimate tensile strength was used as the flow stress (Sflow) and the Code modulus of elasticity (E) was used. The lower bound J-T curve was based on the PlAl hub location. This J-T curve was extrapolated per the procedure in NUREG-1061 Volume 3 [3, Page A20] and SRP 3.6.3, to a value not exceeding twice the J at 0.4 inches as shown in the curve. The J-T curve, shown in Figure 4-4, is based on E = 25,520 ksi and Sflow = 44.485 ksi, consistent with the lower bound stress strain curve derived above, not the specific flow stress for the P1A- hub material. The lower bound J-T values are listed in Table 4-7.

Report No. 0800368.404 4-5 > StructuralIntegrity Associates, Inc.

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Table 4-1. Geometry Table 4-2. Loads at Weld Locations Notes: (a) Normal = Deadweight (DW) + Thermal (THM).

(b) Dead weight and axial shrinkage of WOL and the weld residual stresses are not considered.

(c) Consistent with the net-section collapse models described in SRP 3.6.3 and in Section XI, Appendix C of the ASME code, crack face pressure is not considered.

Report No. 0800368.404 4-6 & StructuralIntegrity Associates, Inc.

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Table 4-3. ASME Code Strength for Nozzle/Piping at Normal Operating Temperature (556°F)

Modulus ASME Code,Section II, Part D Material Sy (ksi) S, (ksi) t7now(ksi) (1) of Component/Material Elasticity Designation Desigation(ksi)

RCP Nozzle RCPGrade Cast Stainless Steel 19.28 67.20 43.24 25,520 A-3 51, Grade CF8M DM Weld Alloy 600 SB-166 (N06600) 30.08 80.00 55.04 28,832 (82/182)

Overlay Alloy 690 SB 166 (N06690) 27.69 80.46 54.08 28,188 (Alloy 52M) Bar/Rod RCP A36 Safe-End Type-316 Stainless Steel 19.38 71.8 45.59 25,520 A-376, Type 316 RCP Piping Carbon Steel 29.94 70.0 49.97 26,964 A-516, Grade 70 Note: (1) Flow stress is average of yield and ultimate tensile strengths for LBB evaluation.

Table 4-4. Ramberg-Osgood Parameters ASME Code,Section II, Ramberg Ramberg Osgood Component/Material Part D Material Osgood Designation Parameter a Exponent n RCP RCP Nozzle 1,zrae Cast Stainless Steel 2.647 3.221 A-351, Grade CF8M DM Weld Alloy 600 SB-166 (N06600) 1.917 3.923 (82/182)

Overlay Alloy 690 SB 166 (N06690) 2.036 3.661 (Alloy 52M) Bar/Rod RCP RCP Safe-End Type-316 Stainless Steel 2.633 3.095 A-376, Type 316 RCP Piping Carbon Steel 1.801 4.379 A-516, Grade 70 Stainless Steel Type Same as RCP Same as RCP Stainless Steel Weld30Nozeozl 308 Nozzle Nozzle Note: All parameters based on the Code minimum yield strength and yield strain (Sy/E).

Report No. 0800368.404 4-7 1 StructuralIntegrity Associates, Inc.

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Table 4-5. Selected J-T Points for Ferritic Base Metal from B&W LBB Evaluation J, in-T lb/in2 0.00 4280.0 38.20 4280.0 38.24 4211.7 38.28 3993.4 38.31 3837.4 38.37 3618.6 38.49 3305.4 38.67 3022.4 38.97 2737.7 39.59 2417.8 40.96 2090.4 42.65 1886.4 45.99 1670.6 50.25 1514.5 58.19 1339.3 69.34 1185.1 90.55 993.2 116.59 827.2 163.22 605.0 Note: T based on E = 26,500 ksi and Sflow = 60 ksi.

Report No. 0800368.404 4-8 V StructuralIntegrity Associates, Inc.

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Table 4-6. Lower Bound Fracture Toughness of Pump Casings Considering Thermal Embrittlement PIA1 PIA2 PIBI P1B2 S/N: 701-N-0240 S/N: 701-N-0242 S/N: 701-N-0243 S/N: 701-N-0241 Hub Scroll Hub Scroll Hub Scroll Hub Scroll S/N: 6795 S/N: 6778 S/N: 6777 S/N: 6774 S/N: 6775 S/N: 6794 S/N: 6793 S/N: 6774 Ht#: 6573 Ht#: 6536 Ht#: 6527 Ht#: 6513 Ht#: 6518 Ht#: 6555 Ht#: 6554 Ht#: 6513

+------------------------+ + 4 + 4 Mechanical Properties Yield Strength (psi) 33000 34500 37000 36000 32000 36000 33500 33750 Ultimate Tensile Str. (psi) 72500 76500 73750 71250 71500 75000 71250 75250 Elongation (%) 51 49.5 59 46 55 48.5 50 60 Chemical Properties Cr 18.6 18.5 18.8 18.8 18.6 18.6 18.3 18.6 Si 0.87 0.93 0.81 0.78 0.72 0.88 0.74 0.74 Mo 2.15 2.16 2.18 2.14 2.19 2.18 2.1 2.15 Ni 9.3 9.4 9.4 9.5 9.6 9.5 9.1 9.42 C 0.06 0.06 0.04 0.02 0.03 0.04 0.05 0.04 Mn 0.98 1.04 0.92 0.8 0.98 1.03 0.98 0.98 N (*assumed) 0.044 0.057 0.04* 0.047 0.047 0.05 0.052 0.051 Creq 16.6 16.6 16.8 16.8 16.6 16.7 16.2 16.6 Nieq 14.4 14.8 14.0 13.7 14.1 14.3 14.2 14.2 Ferrite (6c) 10.6 8.8 14.1 15.5 12.4 11.6 10.3 11.5 20.4 18.9 19.6 14.8 15.5 18.2 17.0 17.3 CVsat (J/cm2) [Polynomial] 127.7 122.5 140.5 174.1 187.2 144.7 188.8 171.7 Cvsat (J/cm 2) [D] 104.0 119.2 112.4 180.7 166.9 127.6 143.2 139.3 MinimumCvsat (J/cm 2 ) 104.0 119.2 112.4 174.1 166.9 127.6 143.2 139.3 C (J-R Curve Constant) 5739.2 6135.7 5961.9 7386.1 7234.9 6342.3 6712.5 6621.9 N (J-R Curve Exponent) 0.345 0.348 0.347 0.358 0.357 0.350 0.353 0.352 J1, (in-lb/in2) 1429.2 1532.3 1486.9 1867.7 1826.3 1586.6 1684.9 1660.7 Ki, (ksi-in*) 200.1 207.2 204.1 228.8 226.2 210.9 217.3 215.7 Report No. 0800368.404 4-9 V StructuralIntegrity Associates, Inc.

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Table 4-7. Lower Bound J-T Curve Based on Davis-Besse Pump Materials J, in-T lb/in2 0.00 6393.866 46.54 48.13 4110.33 49.86 4034.37 53.86 3873.72 58.78 3699.31 65.03 3507.71 73.28 3293.87 84.82 3049.81 102.41 2761.65 133.60 2401.14 210.65 1890.44 634.58 1084.97 Note: Extrapolation between two asterisked values.

Report No. 0800368.404 4-10 V StructuralIntegrity Associates, Inc.

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(a) Suction Nuzzle 1 2 3 4 (b) Discharge Nozzle Figure 4-1. Schematic Diagrams of RCP Nozzle Weld Overlay Design 4500 4000 3500 c.4 3000 2 2500 - -- Equation

.S 2000 Select Points 1500 1000 500 0

0 50 100 150 200 T

Figure 4-2. J-T Curve for Ferritic Base Metal from B&W LBB Evaluation Report No. 0800368.404 4-11 V StructuralIntegrity Associates, Inc.

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80 _____~ Hu 70 ___PIAl Scroll 6 o0 --- P1A2Hub 5 o0 __] P1A2 Scroll U, 4 0 .. . PB1A Hub 30 ___PiBi Scroll 2 o0 -- P1B2 Hub 10 ..-.....

---

... - P1B2 P Scroll 0

S-a-- Lower Bound 0 0.05 0.1 0.15 Strain, in/in Figure 4-3. Stress Strain Curves for All RCP CASS Heats 7000 6000 6-PlAl Hub

-PlAl Scroll 5000 P1A2 Hub 4000

.0 -40P1A2Scroll

-- P1B1 Hub

.E3000 3-B1B1 Scroll P1B2 Hub 2000

-P1 B2 Scroll 1000 1000 Lower Extrap 0

0 100 200 300 400 T

Figure 4-4. J-T Curve Determination Report No. 0800368.404 4-12 V StructuralIntegrity Associates, Inc.

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5.0 CRITICAL FLAW SIZE EVALUATION 5.1 Methodology The LBB evaluation is performed for the RCP suction and discharge nozzles dissimilar metal welds (DMW). The limit load methodology described in Appendix A will be used to determine the critical flaw size. This is consistent with the approach provided in SRP 3.6.3 for limit load evaluation except that it considers the combination of geometry and material properties for a section with two different materials. For consideration of crack locations with low toughness material, Z-factors are used, consistent with the methods currently implemented in ASME Section XI for evaluation of austenitic weldments and, ferritic piping and associated weldments.

5.2 Z-Factor The net section collapse methodology described in Appendix A requires the application of Z-factors which account for the low toughness of the materials under consideration.

The DM weld material between the nozzle/safe end and the elbow is Alloy 600 (82/182). It is conservatively assumed that this weld was fabricated by flux welding with either submerged arc welding (SAW) or shielded metal arc welding (SMAW) and as such a Z factor has to be considered. The determination of the Z factor for the Alloy 82/182 flux weldment is provided in Reference 27. The Z-factor so determined is 1.21 for the 34-inch OD piping at the RCP suction and discharge nozzles. This Z-factor was used for the evaluation of the DM welds for the overlaid condition.

The Z-factors for ferritic/carbon steel base metals and associated weld metals as well as for austenitic weld materials fabricated using shielded metal arc (SMAW) or submerged arc (SAW) welding are calculated conservatively from the ASME Code,Section XI, Appendix C [8]. For conservatism, the Z-factor for the SAW is applied for the cast austenitic stainless steel. The use of these Z-factors is also confirmed by performing an EPFM analysis for the Davis-Besse pipe material.

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The weld overlay is identified as a GTAW weld, thus for the Alloy 52M overlay, the Z-factor is 1.0 per ASME Code,Section XI, Appendix C [8].

Since actual material properties are available, additional analyses were performed to determine Z-factors for the carbon steel elbow and RCP nozzle CASS material. The lower bound J-T curves of the ferritic base metal and CASS material provided in the Section 4 are used for the analyses. The geometry and loading conditions for 28" (nominal ID) straight pipe, which is made of the ferritic material, are provided in Reference 1 as follows:

Di = 28.5 in (Table 3-6 of Ref. 1)

Thickness = 2.375 in (Table 3-6 of Ref. 1)

Meq = 50264 in-kips (Table 4.8 of Ref. 1)

E = 26500 ksi (Table 3-6 of Ref. 1)

Gy = 39 ksi (Section 4.4.2 of Ref. 1)

Gult = 81 ksi (Section 4.4.2 of Ref. 1)

Gflow = 60 ksi (Section 4.4.2 of Ref. 1) a = 1.48 (Section 4.4.2 of Ref. 1) n = 5.05 (Section 4.4.2 of Ref. 1) acrit = 10.18 in (Section 2.0 above) where, Meq = equivalent moment which combines the applied force (including end cap pressure) and moment a, n = Ramberg-Osgood parameter For the CASS material, the geometry for Path 1 of the suction nozzle from Table 4-1 and a moment only loading equal to Meq are used in the analysis to confirm the Z-factor.

Limit load calculations and tearing instability analyses are performed using pc-CRACK [28] to determine the critical flaw lengths. The Z-factors are then determined as the ratio of the limit load and EPFM results. The Z-factor for the carbon steel material of the RCP piping is calculated to be 1.7 (=39.1/22.8) and for the CASS material 1.7 (=43.4/25.2). Comparing to the Report No. 0800368.404 5-2 StructuralIntegrity Associates, Inc.

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Z-factors obtained from using the ASME Code which listed in Table 5-1, the Z-factor for the carbon steel is less when the actual material properties are used whereas the Z-factor for the CASS material is consistent between the two methods. The larger Z-factor for the carbon steel material from the ASME Code will be conservatively used in the critical flaw evaluation.

Table 5-1 summarizes the Z-factors for the all the materials of the RCP suction and discharge nozzle components considered in the DM weld overlay LBB evaluations.

5.3 Critical Flaw Size Critical flaw sizes were determined using the methodology of Appendix A assuming the crack length was the same for the weld overlay and the underlying base material, consistent with the assumption of a constant length through-wall crack in SRP 3.6.3 [2]. For each of the RCP suction and discharge nozzles, the critical flaw sizes are calculated for the optimized (OWOL) and full structural (FSWOL) designs. Table 5-2 shows the resulting critical crack lengths. It can be seen that, in comparison to the original LBB evaluation, the critical flaw sizes at the carbon steel path are at least twice as large, showing the beneficial effect of the application of the weld overlay in terms of critical flaw size.

5.4 Critical Flaw Size Comparison to Original Evaluation A case was also run to check the compatibility of the methodology in this evaluation with respect to the original LBB report [1]. The test case uses the geometry, material properties, and loads in the original critical flaw size evaluation. Below, are the parameters of the 28 inches (nominal ID) straight pipe used for the test case:

" Pipe ID = 28.5 in (Table 3-6 of Ref. 1)

• Pipe thickness = 2.375 in (Table 3-6 of Ref. 1)

• Pipe base metal flow stress = 60 ksi (Section 4.4.2 of Ref. 1)

• Pipe base metal yield stress = 39 ksi (Section 4.4.2 of Ref. 1)

• Monient loadings = 50264 in-kips (Table 4-8 of Ref. 1)

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The operating temperature and pressure used for the original leakage calculations were 550'F (Section 4.4.1 of Ref. 1). The equivalent moment combines the applied force (including 2.25 ksi end cap pressure, Table 4-11 of Ref. 1) and bending moment.

In the original critical flaw size evaluation, the critical flaw length 28" (nominal ID) straight pipe using elastic plastic fracture mechanics (EPFM) is 20.2 inches [1]. In this calculation, using limit load analysis with the Z-factor of 1.83 for the carbon steel material, the critical flaw size is 19.70 inches. This shows that the methodology employed in this evaluation produces results comparable but conservative relative to that presented in the original LBB report.

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Table 5-1. Z-factors for Base Metals and Welds at DMW Location Nozzle (Cast Safe End Nozzle-SE Elbow (Carbon Z-factor Stainless Steel) (Stainless Steel) Weld (DMW) Steel)

Suction Nozzle 1.70 (1) N/A 1.21 1.82 (1)

Discharge Nozzle N/A 1.0 1.21 1.83 (1)

Note: (1) Z-factors of 1.7 were computed for the cast stainless steel and carbon steel materials based on limit load and J-T analyses.

Table 5-2. Critical Flaw Size Results Suction Nozzle, in Discharge Nozzle, in Crack FSWOL Design FSWOL Design OWOL Design Location Min. WOL Max. WOL Min. WOL Max. WOI Min. WOL Max. WOL Thickness Thickness Thickness Thickness Thickness Thickness Path 1 49.79 51.31 48.29 50.24 46.51 48.96 Path 2 56.78 57.89 48.34 50.24 46.61 48.99 Path 3 54.74 55.90 50.73 53.09 49.12 52.02 Path 4 48.33 49.88 41.85 45.21 39.47 43.70 Report No. 0800368.404 5-5 Revision: 1 V StructuralIntegrityAssociates, Inc.

6.0 LEAKAGE EVALUATION 6.1 Methodology The leakage for 1/2 critical flaw sizes was evaluated using the PICEP [29] computer program.

Since PICEP will only evaluate a single material, equivalent material properties are derived to use with PICEP. The total weld overlay thickness is used in the model for purpose of computing the leak rate, along with a methodology to evaluate crack morphology as described in Appendix B.

6.2 Leakage Evaluation The following summarizes the assumptions for the PICEP model:

1. A minimum design thickness and a maximum thickness overlay are evaluated for the FSWOL as well as OWOL, respectively. These two thicknesses for each design are considered to be sufficient to demonstrate the effect of LBB for other intermediate thicknesses.

2. The strength of the overlay material is taken to be equivalent to that of similar Alloy 690 base material, where Code properties are available.

3. The leakage analysis is based on normal operation conditions (556°F and 2150 psia), consistent with the conditions used for critical flaw sizing.

4. PICEP options are use as follows:

a. The option for combining axial forces and moments is used.

b. A plastic zone correction is included. This is consistent with fracture mechanics principles for ductile materials.

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c. The crack is assumed to be elliptical in shape with the inlet area equal to the exit area.

d. Crack roughness is taken as 0.000 197 inches for fatigue cracking [30] in materials other than the ALLOY 82/182 weld. There are no turning losses assumed for fatigue cracking. This is consistent with the roughness used in the B&W evaluation [1, Page 3-9].

e. A sharp-edged entrance loss factor of 0.61 is used (PICEP default).

f. The default friction factor equations of PICEP are utilized.

5. For the weld with Alloy 82/182 material, the adverse effects of PWSCC crack morphology are considered for the affected material as described in Appendix B; for other materials, the crack morphology for fatigue cracking is used. This is consistent with the approach used in the original LBB evaluation and is consistent with the factors of two on crack size and ten on leakage specified in SRP 3.6.3.

6. The adverse effects of PWSCC crack morphology will be considered for the weld with Alloy 600 (82/182) (SCC susceptible material). The assumed PWSCC crack morphology is taken from Reference 31 for a crack parallel to the long direction of the dendritic grains.

7. For leakage determination, the individual values of the normal operating loads (i.e., deadweight, thermal expansion, and pressure) are algebraically combined and applied to determine the leakage flaw size.

8. The loads and material properties are as described in Section 4.

9. For evaluation of PWSCC morphology, the flow loss coefficient K9 0 is taken as 1.0 for a turn as discussed in Appendix B.

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10. To determine properties for the leakage evaluations with PICEP, composite material properties were determined based on the relative thicknesses of the base material and the weld overlay. For example, the following equation shows the yield stress.

x (tbao x Se + tWo x S YW)

(tbase + tWOL )

This approach applies to modulus of elasticity, yield strength, and Ramberg/Osgood parameters. The Ramberg-Osgood parameters (a and n) listed in Tables 6-1 were determined using the methodology from Reference 24 as described in Appendix C.

6.3 Results Leakage flaw sizes were calculated based on a combination of PWSCC and fatigue crack morphologies for the Alloy 82/182 DM welds. For the non-susceptible metals, only the fatigue crack morphology was used. The leakage flaw sizes, which result in 10 gpm leakage for each of the postulated flaw paths, are calculated and shown in Tables 6-2 for the RCP suction and discharge nozzles for the optimized (OWOL) and full structural (FSWOL) designs. In addition, the leak rate through the calculated half critical flaw sizes are also determined and presented in Table 6-3. In all cases, the leakage is significantly above the 10 gpm limit that was the acceptance criteria of the original LBB analysis.

Comparing the critical flaw sizes in Table 5-2 and leakage flaw sizes in Table 6-2, the flaw size margin between the critical flaw sizes and leakage flaw sizes for each postulated crack path in the DM weld and adjacent base material are listed in Table 6-4. The minimum calculated flaw size margin is 2.80 which is larger than the required margin of 2 on critical flaw size.

6.4 Leakage Comparison to Original Evaluation -

To show consistency of the leakage results with the previous B&W evaluation [1], several cases were run with the original, un-overlaid pipe employing the present methodology. Below are the parameters used for the evaluation:

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A. 28 inches (nominal ID) Straight Pipe (Tables 3-1 and 3-6 of Reference 1)

• PipelD = 28.5 in

" Pipe thickness - 2.375 in

• Moment Loadings = 6720, 13140, 14952 in-kips

• Yield Stress = 29600 psi

• Young's Modulus = 26500000 psi B. 28 inches (nominal ID) Elbow Pipe (Tables 3-1 and 3-6 of Reference 1)

• Pipe ID = 28.5 in

• Pipe thickness = 3.125 in

• Moment Loadings = 14952, 10452, 15336 in-kips

• Yield Stress 28100 psi

" Young's Modulus = 26500000 psi The operating temperature and pressure used for the original leakage calculations were 600'F and 2150 psi (assumed to be 2150 psia), respectively. No force loading is used in the original leakage calculation. A flaw surface roughness of 0.000197 inches is used, consistent with the original evaluation. In the original report, no Ramberg-Osgood parameters are provided.

Therefore, it was conservatively assumed that the plastic crack opening is negligible, which is ensured in the PICEP input file by using a = 0.001 and n = 1. Also, the following parameters are not provided in the original LBB report, and therefore, the PICEP defaults are assumed:

" Crack area at exit/Crack area at inlet (PICEP default = 1.0)

" Number of IGSCC 90 degree turns (PICEP default = 0)

" Number of IGSCC 45 degree turns (PICEP default = 0)

" Entrance Loss Coefficient Cd (PICEP default = 0.61)

" Friction factor (PICEP default = 0)

The results of the evaluation are presented in Table 6-5 which shows a comparison between the B&W report and the present evaluation of the leakage flaw sizes for a 10 gpm leak rate. It can be seen that the results are comparable, showing a maximum difference of 15%. The leakage crack sizes using PICEP are consistently slightly smaller (slightly more leakage for a given crack size) than the original LBB evaluation. The discrepancy in the results may be due to the material Report No. 0800368.404 6-4 ___ Structural IntegrityAssociates, Inc.

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(Ramberg-Osgood) parameters used and the leakage calculation algorithm in the original LBB report [1]. These results show that the current methodology using PICEP for the leakage evaluations in pipes with weld overlay is comparable to the original LBB evaluation methodology described in the B&W report [1]. Tables 6-2 and 6-3 are produced employing the current methodology using PICEP whereas, Table 6-5 compares the leakage flaw sizes for 10 gpm leak rate reported in the B&W report with the leakage flaw sizes for 10 gpm leak rates calculated using PICEP for the same input loadings.

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Table 6-1: ASME Code Minimum Ramberg-Osgood Parameters ASME Code,Section II, Ramberg Ramberg Component/Material Part D Material Osgood Osgood Designation Parameter, a Exponent, n RCP Nozzle A-351, Grade CF8M 1 Cast Stainless Steel 2.481 3.313 DM Weld Alloy 600 SB-166 (N06600) 1.917 3.923 (82/182)

Overlay Alloy 690 SB 166 (N06690) 2.036 3.661 (Alloy 52M) Bar/Rod RCP A36 Safe-End Type-316 Stainless Steel 2.633 3.095 A-376, Type 316 RCP Piping Carbon Steel 1.801 4.379 A-516, Grade 70 1 4.1 Note 1: CASS properties as calculated based on material properties in Reference 25.

Table 6-2: Leakage Flaw Size for 10 gpm Leak Rate Suction Nozzle, in Discharge Nozzle, in Crack FSWOL Design FSWOL Design OWOL Design Location Mi. Max. WOL Min. WOL Max. WO_ Min. WOL Max. WOL WOL Ti e Thickness Thickness Thickness Thickness Thickness Thickness Path 1 Nozzle/SE at 10.82 11.19 8.91 9.48 8.40 9.10 Weld Path 2 Weld/Nozzle 19.56 19.96 16.87 17.45 16.35 17.06 Side Path 3 Weld Elbow 18.37 18.77 18.03 18.78 17.53 18.43 Side Path 4 Elbow at 11.27 11.61 10.54 11.17 10.14 10.88 Weld Report No. 0800368.404 6-6 Revision: 1 C StructuralIntegrity Associates, Inc.

Table 6-3: Leak Rate for Leakage Flaw Size Equal to Half Critical Flaw Size Suction Nozzle, gpm Discharge Nozzle, gpm Crack FSWOL Design FSWOL Design OWOL Design Location Min. WOL Max. WOL Min. WOL Max. WOL Min. WOL Max. WOL Thickness Thickness Thickness Thickness Thickness Thickness Path 1 Nozzle/SE a 152.21 153.61 245.59 236.86 253.59 242.71 Weld Path 2 Weld/Nozzi 34.52 34.62 30.96 31.61 30.24 31.22 Side Path 3 Weld Elbow 37.32 37.34 29.55 30.25 28.98 29.99 Side Path 4 Elbow at 114.05 117.51 82.53 91.20 75.78 87.44 Weld Report No. 0800368.404 6-7 V StructuralIntegrity Associates, Inc.

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Table 6-4: Margin on Flaw Size in Welds and Base Materials Suction Nozzle, in Discharge Nozzle, in Crack FSWOL Design FSWOL Design OWOL Design Location Min. WOL Max. WOL Min. WOL Max. WO_ Min. WOL Max. WOL Thickness Thickness Thickness Thickness Thickness Thickness Path 1 Nozzle/SE a Weld 4.60 4.59 5.42 5.30 5.54 5.38 Path 2 Weld/Nozzi Side 2.90 2.90 2.87 2.88 2.85 2.87 Path 3 Weld Elbo Side 2.98 2.98 2.81 2.82 2.80 2.82 Path 4 Elbow at Weld 4.29 4.30 3.97 4.05 3.89 4.02 Table 6-5: Leakage Flaw Size Comparison for 10 gpm Leak Rate of the Original B&W Leakage Analysis with The Current Analytical Approach Using PICEP Leakage Flaw size for 28 inches (nominal ID) Leakage Flaw size for 28 inches (nominal ID)

Straight Pipe, in Piping Elbow, in Moment Moment Flaw-B&W Current Flaw-Size Loading, in- Loadig n-SizeB&W Current Evaluation Evaluation Ratio (1) ding, in- Evaluation Evaluation kips kips Ratio (1) 6720 9.2 8.09 0.88 14952 9.0 8.14 0.90 13140 7.9 6.82 0.86 10452 9.6 9.04 0.94 14952 7.7 6.55 0.85 15336 9.0 8.08 0.90 Note: (1) Current Evaluation/B&W Evaluation.

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7.0 CONCLUSION

S The effect of applying weld overlay repairs on the DM welds of the RCP suction and discharge nozzles at Davis-Besse Unit 1 has been evaluated. It has been shown that the application of the weld overlay results in residual stresses that are either significantly reduced or compressive at the inside surface and compressive in the inner portion of the dissimilar metal weld. These stresses will mitigate the effects of PWSCC in the Alloy 82/182 dissimilar metal weld. Furthermore, the use of highly resistant Alloy 52M weld metal, combined with improved inspection capability, will provide additional assurance that through-wall cracks cannot occur at the DM weld locations. Crack growth evaluations performed as part of the evaluation indicated that combined PWSCC and fatigue crack growth for axial and circumferential postulated flaws is within acceptable limits for a 10-year inspection interval.

This evaluation has been conducted using LBB assumptions similar to that used in the original B&W evaluation, modified slightly to account for the addition of the weld overlays. The evaluation has demonstrated that with the application of the weld overlay, the LBB margins required in SRP 3.6.3 and NUREG-1061, Vol. 3 are maintained. In fact, the margin on flaw size at the 28" pipe/elbow DM welds and adjacent base materials at Davis-Besse Unit 1 is increased as compared to that accepted by the Nuclear Regulatory Commission in the original LBB submittal, from 2.2 to at least 2.80. The effect of the application of the weld overlay is to increase the critical flaw size, resulting in additional margin between the critical flaw size and the leakage flaw size, even though leakage tends to be reduced due to the longer flow path and considerations of crack morphology for the Alloy 82/182 weld location.

A range of weld overlay thicknesses was also evaluated, showing that the actual thickness attained during overlay application does not change the LBB behavior significantly.

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8.0 REFERENCES

1. Report BAW-1847, "The B&W Owners Group Leak-Before-Break Evaluation of Margins Against Full Break for the RCS Primary Piping of the B&W-Designed NSS," Rev. 1.

2. a. NUREG-0800, "U.S. Nuclear Regulatory Commission Standard Review Plan, Office of Nuclear Reactor Regulation, Section 3.6.3, Leak-Before-Break Evaluation Procedure," March 1987.

b. NUREG-0800, "U.S. Nuclear Regulatory Commission Standard Review Plan, Office of Nuclear Reactor Regulation, Section 3.6.3, Leak-Before-Break Evaluation Procedure," Revision 1, March 2007.

3. NUREG-1061, Volume 3, "Report of the U.S. Nuclear Regulatory Commission Piping Review Committee," prepared by the Piping Review Committee, NRC, April 1985.

4. NRC Letter To Toledo Edison,

Subject:

Safety Evaluation of B&W Owners Group Reports Dealing with Elimination of Postulated Pipe Breaks in PWR Primary Main Loops, Davis-Besse Nuclear Station, Unit 1, Docket Number 50-346, Dated February 18, 1986.

5. Centerior Energy letter to NRC,

Subject:

Comparison of Davis-Besse Reactor Coolant System Leak Detection Systems to Regulatory Guide 1.45. Docket Number 50-346, License Number NPF-3, Serial Number: 1849, November 6, 1990.

6. Materials Reliability Program: Technical Basis for Preemptive Weld Overlays for Alloy 82/182 Butt Welds in PWRs (MRP-169), Rev. 1, EPRI, Palo Alto, CA: 2008. 1016602.

7. ASME Section XI Task Group for Piping Flaw Evaluation, ASME Code, "Evaluation of Flaws in Austenitic Steel Piping," Journal of Pressure Vessel Technology, Vol. 108, August 1986, pp.

352-366.

8. ASME Boiler and Pressure Vessel Code,Section XI, 2001 Edition with 2003 Addenda.

9. ASME Code Case N-504-3, "Alternative Rules for Repair of Classes 1, 2, and 3 Austenitic Stainless Steel Piping,"Section XI, Division 1.

10. ASME Code Case N-740-2, "Dissimilar Metal Weld Overlay for Repair or Mitigation of Class 1, 2, and 3 Items,Section XI, Division 1.

11. EPRI NP-7103-D, "Justification for Extended Weld Overlay Design Life," Topical Report, January 1991.

12. EPRI NP-5881-LD, "Assessment of Remedies for Degraded Piping," June 1988.

13. ANSYS/Mechanical, Revision 8.1 (w/Service Pack 1), ANSYS Inc., June 2004.

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14. NUREG/CR-6721, "Effects of Alloy Chemistry, Cold Work, and Water Chemistry on Corrosion Fatigue and Stress Corrosion Cracking of Nickel Alloys and Welds, "U.S. Nuclear Regulatory Commission (Argonne National Laboratory), April 2001.

15. NUREG/CR-6907, "Crack Growth Rates of Nickel Alloy Welds in a PWR Environment," U.S.

Nuclear Regulatory Commission (Argonne National Laboratory), May 2006.

16. Materials Reliability Program: Crack Growth Rates for Evaluating Primary Water Stress Corrosion Cracking (PWSCC) of Alloy 82, 182, and 132 Welds (MRP- 115), EPRI, Palo Alto, CA: 2004. 1006696.

17. FENOC Relief Requests RR-A32 and RR-A32, transmitted via FENOC Letter L-09-020, dated January 30, 2009.

18. Performance Demonstration Initiative (PDI) Program Description, Rev. 2, Oct. 1, 2000.

19. U.S. Nuclear Regulatory Commission, 10CFR50.55a.

20. NUREG-0313, "Technical Report on Material Selection and Processing Guidelines for BWR Coolant Pressure Boundary Piping," Revision 2, January 1988.

21. Materials Reliability Program: Primary Systems Piping Butt Weld Inspection and Evaluation Guidelines (MRP-139), EPRI, Palo Alto, CA: 2005. 1010087.

23. ASME Boiler and Pressure Vessel Code,Section II, MaterialProperties,2001 Edition with Addenda through 2003.

24. Cofie, N.G., Miessi, G.A., and

Deardorff,

A.F., "Stress-Strain Parameters in Elastic-Plastic Fracture Mechanics," Transactions of the 1 0 th International Conference on Structural Mechanics in Reactor Technology, Volume L - Inelastic Behavior of Metals and Constitutive Laws of Materials, August 14-18, 1989, Anaheim, Ca, USA, pp 91-96.

25. SI Report SIR-99-040, "ASME Code Case N-481 Evaluation of Davis-Besse Reactor Coolant Pumps," Rev. 1, September 27, 2000.

26. NUREG/CR-4513, "Estimation of Fracture Toughness of Cast Stainless Steels During Thermal Aging in LWR Systems," Rev. 1, U.S. Nuclear Regulatory Commission, August 1994.

27. Wilkowski, G, et.al., "Determination of the Elastic-Plastic Fracture Mechanics Z-factor for alloy 82/182 Weld Metal Flaws for Use in the ASME Section XI Appendix C Flaw Evaluation Procedures," Proceedings of ASME-PVP 2007.

28. pc-CRACK TM for Windows, Structural Integrity Associates, Version 3.1-98348, 1998.

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29. D. M. Norris and B. Chexal, "PICEP: Pipe Crack Evaluation Program (Revision 1)," EPRI NP-3596-SR, Revision 1, December 1987.

30. D. Abdollahian and B. Chexal, "Calculation of Leak Rates Through Cracks in Pipes and Tubes,"

EPRI NP-3395, Electric Power Research Institute, Palo Alto, CA, December 1983.

31. Wilkowski, G., Wolterman, R., and Rudland, D., "Impact of PWSCC and Current Leak Detection on Leak-Before-Break Acceptance," Proceedings of ASME Pressure Vessels and Piping Division Conference, Denver, CO, July 17 to July 21, 2005.

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APPENDIX A CRITICAL FLAW SIZE EVALUATION METHODOLOGY Report No. 0800368.404 A-1 StructuralIntegrityAssociates, Inc.

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A.1 INTRODUCTION Appendix C of Section XI of the ASME Code [A-I] has a method for evaluating flawed piping using net section collapse limit load methods. The methodology is based on a single material thin cylinder and can be used to determine the critical through-wall flaw size for an overlaid pipe. A modified approach is developed herein based on similar limit load methods, but has some additional considerations:

A.2 TECHNICAL APPROACH A.2.1 Net Section Collapse Model for Cracked Pipe with Weld Overlays Standard Review Plan (SRP) 3.6.3 [A-1] provides methods for determining critical flaw size using net section collapse model. The original methodology, as described in Reference 1, is based on a single material cylinder. In the present case, the original weld is repaired by applying a weld overlay using a different material compared to the original weld material. Hence, a revised methodology is needed to consider both the materials such that the intent of SRP 3.6.3 can be met.

Deardorff,

A, et al. proposed a method [A-2] to determine the critical through-wall flaw size for circumferential cracked pipe with weld overlays. It is based on net section collapse solution, but has some additional considerations due to the weld overlay:

• The effects of two materials are considered. The limit load tensile force and bending moment can be evaluated for the circumferential cracked pipe with weld overlays.

• The analytical model allows for the arbitrary definition of the circumferential through-wall crack length for the weld overlay, while both circumferential crack length and depth (in the radial direction from the inside wall) for the base material.

• The evaluation method allows for a reduction in the fracture toughness to be considered. The Z-factor for the reduced toughness material (e.g. thermal aged material) can be applied to the specific material.

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• Optionally, the effect of internal pressure on the crack surface of both base material and weld overlay can be evaluated.

A.2.2 Methodology Figure A-1 shows a sketch of the cross section of a cracked pipe with weld overlay. The notations in the figure are defined as follows:

a = half through-wall (TW) crack angle in weld overlay P3 = half TW crack angle in original pipe (can be different than a) y = neutral axis angle ra = mean radius of weld overlay rb = mean radius of the uncracked material of the original pipe r, = mean radius of the original pipe rd= mean radius of the'cracked material of the original pipe ri = inside radius of original pipe ta = thickness of weld overlay tb = thickness of the uncracked material the original pipe t, = thickness of original pipe td = thickness of the cracked material of the original pipe (t, - tb)

The axial force equilibrium of can be expressed as:

R= -rAdO- - AdO+ - BdO- fCdO where, R = half of the axial load (including axial force introduced by internal pressure)

A =cfrat, B =jb rbtb Report No. 0800368.404 A-3 StructuralIntegrity Associates, Inc-Revision: 1

C = ort, af, = flow stress of weld overlay aj = flow stress of original pipe Therefore, the neutral angle y is given by:

(A +B); - aA --/B -R 2A+B+C Employing moment equilibrium, the plastic collapse moment can be expressed as:

M, f A' cos OdO - fA'(- cos O)dO + yr B'cos OdO - C'(- cos O)dO where, Mb = half of the plastic collapse bending moment A' =Ara,= zora2 ta 2

B' =Brb=ojqbrb tb C' =Crc=U tc 2rc The remote bending stress in the uncracked pipe, based on shell theory is:

b, rMt (2)

As defined in ASME Code (Ref. [3]), the failure bending stress is defined as P1b = SF(P,, + Pb) -P- for high toughness material P1b = Z(SF)(Pm + Pb + P, / SF) - for low toughness material Report No. 0800368.404 A-4 V StructuralIntegrityAssociates, Inc.

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where, Pe = primary membrane stress Pb = primary bending stress Pe = thermal expansion bending stress SF = safety factor Z = Z-factor for correcting for low toughness material In the weld overlay process, the overlay material is usually Alloy 690 (52M) deposited using GTAW.

Hence, Z-factor is only needed to apply on the base material. Equation 5 of Reference 2 describes how the plastic collapse bending stress may be conducted for a two layer configuration as follows:

PPb =(1 -M*)[SF(Pm + Pb) - P + M* [Z(SF)(Pm + Ph + P, / SF) - P (3) where, M* = ratio of tension region material axial load due to underlying material by total axial load for tensile material Note that in the above expression, M* is determined based on the axial load ratio, not the moment ratio as in Reference 2. Experience show that use of the moment ratio could result in unrealistic M* values that are greater than 1.0 or less than zero due to the fact that the moment contribution due to material below the neutral axis can be negative.

With this approach, if it is assumed that the entire underlying material is cracked above the neutral axis, then AJ4 = 0 and the equation collapses back to the form for high toughness material. If there is no overlay material, then M* = 1.0, and the equation becomes that for a low-toughness material where the complete effect of the thermal expansion moment must be included in the evaluation.

Substituting the neutral axis angle in Equation (1) into Equation (2), Equation (2) and Equation (3) can be solved and the critical circumferential flaw length for fixed crack depth in the base material can be obtained.

Report No. 0800368.404 A-5 StructuralIntegrity Associates, Inc.

Revision: 1

A.3 REFERENCES A-1. U.S. Nuclear Regulatory Commission, Standard Review Plan 3.6.3, "Leak-before-Break Evaluation Procedures," Revision 1, March, 2007.

A-2.

Deardorff,

A. F., Cofie, N. G., Dijamco D. G. and Chintapalli A., "Net Section Plastic Collapse Analysis of Two-Layered Materials and Application to Weld Overlay Design,"

PVP2006-ICPVT 11-93454, ASME PVP Conference 2006.

A-3. ASME Boiler and Pressure Vessel Code,Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components (various Editions and Addenda).

Report No. 0800368.404 A-6 StructuralIntegrityAssociates, Inc.

Revision: 1

Original Pipe/Weld Original Pipe/Weld Overlay (Uncracked)

(Under Compression) aTension 4-Co t

Neutral Axis Gflow-OWL (Yflow-Base G*flow-Base <

(3flowOWL <- Compression Figure A-1. Schematics of a Circumferentially Cracked Section with Weld Overlay Report No. 08003 68.404 A-7 A StructuralIntegrity Associates, Inc.

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APPENDIX B LEAKAGE EVALUATION METHODOLOGY Report No. 0800368.404 B-1 V StructuralIntegrityAssociates, Inc.

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B.1 LBB METHODOLOGY Leak-before-break evaluations require that leakage be calculated for the loads in piping systems expected during normal operation. This typically includes the loads due to pressure in the piping and due to moments and axial forces resulting from dead weight and thermal expansion of the piping system.

In the original LBB evaluations for most plants, the leakage was calculated based on fatigue crack morphology, where the crack surface was expected to be quite smooth. Based on the occurrence of PWSCC in PWR piping systems, the potential existence of PWSCC cracking must be considered where the cracking could occur in susceptible materials. This is considered in the cases where a non-susceptible weld overlay is installed on a susceptible Alloy 82/180 weldment.

B.2 MORPHOLOGY EFFECTS ON LEAKAGE EVALUATION Battelle Columbus and Engineering Mechanics Corporation of Columbus (EMC 2) have conducted research to assess the technology used in determining leakage through cracked piping with SCC morphology [B-1, B-2, B-3]. It has been determined that the crack morphology, characterized by the local roughness, number of flow path turns, and total leakage path length,-is significantly different between fatigue cracking and SCC. For fatigue cracks, the flow path is relatively smooth and straight, whereas for SCC, the flow path is relatively rough and consists of many turns. A procedure has been proposed in NUREG/CR-6300 [B-2] that defines the surface roughness, effective flow path length and number of flow path turns as a function of the ratio of the crack opening displacement (COD, 6) to the global roughness ([tG) of the flow path. For very tight cracks, there is a relatively longer flow path with many local turns, but the local roughness is relatively lower. For cracks with a much larger opening, the roughness is better represented by the global roughness but the number of turns and effective flow path length decrease. Although Report No. 0800368.404 B-2 StructuralIntegrity Associates, Inc.

Revision: 1

not confirmed by testing or detailed fluid mechanics analysis, this model is a reasonable representation of the morphology effects due to SCC on leakage flow.

For defining the crack morphology, the model proposed by Battelle is considered that take into account both global roughness ýtG and the local roughness VIL as illustrated in Figure B-2 [B- I].

These are then combined with 6, the COD, by the following set of equations to develop an effective roughness pt.

AL, 0.0 -. - < 0].1 1

AG A A~IG-AL t5 -0.1 0.1!;i 51 AG, - > 10 (B-1)

A similar set of equations were developed to determine the effective number of turns (NT), with the assumption that the number of turns decreases to about 0. 1 of the local number of turns, (NL) when the crack opening displacement is equal to 10 times or more the global roughness.

htL 0.0 :5 <0.1 TzG 0 > 10

/.G (B-2)

Similarly, the total flow path length is increased due to the crack being skewed relative to the pipe wall and due to the turns within the material, as shown in Figures B-I and B-2. Then, the ratio between the total flow path length La and the pipe wall thickness t is determined by:

Report No. 0800368.404 B-3 Structural IntegrityAssociates, Inc.

Revision: 1

Ko÷L, 0.0 - < 0.1 AG

.KL- KG.,AK<

K_,L-K9 5 -0.1 , 0.1 g 10 t 9.9 G K0 , > 10 (B-3)

The EPRI-developed computer program PICEP [B-4] is not configured to directly include the methods for computing morphology using the interpolation method proposed in NUREG/CR-6300. To determine the effects of crack morphology on leakage flaw sizes, additional calculations can be conducted using PICEP with input revised to simulate SCC morphology.

It is further observed that the method used in PICEP for addressing the effects of number of turns is not consistent with the approach used in the NRC-sponsored SQUIRT computer program developed by Battelle for computation of leakage through pipes and tubes [B-5]. In PICEP, the number of turns has been determined (by performing a number of different analyses) to be simulated by adding an equivalent L/D=26 for 45-degree turns and L/D=50 for 90-degree turns.

These equivalent additional lengths are appropriate for use.determination of pressure drop through typical piping components. However, when the roughness (F) is increased to be large comparable to the hydraulic diameter (DH), the effect of the number of turns is further amplified since it is multiplied by an increased friction factor (f). In SQUIRT, a more fundamental approach is used for the number of turns in that it is recommended that a turn be equivalent to the loss of one velocity head, without the additional multiplying factor of increased roughness.

To determine input to PICEP to simulate a crack with both fatigue and PWSCC morphology in the same crack, an equivalent number of turns and equivalent roughness are determined. The method is based on the fact that the flow resistance along a flow path is made up of the friction resistance and the discontinuity (e.g., turns) resistance. The pressure differential is determined by multiplying the sum of the friction (fL/D) and discontinuity (K) loss factors by the velocity pressure in the flow path.

Report No. 0800368.404 B-4 StructuralIntegrityAssociates, Inc.

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In PICEP the turns and friction resistance are lumped together.

Loss Factor = f (t/Dh + 50N 90) for 90 degree turns

- f (t/Dh + 26N 45) for 45 degree turns where f = friction factor

-. (2 log(DH/2 &)+ 1.74)-2 [B-4]

= roughness (defined as ýt by Battelle) t = pipe wall thickness N 90,N45 = number of 90-degree or 45-degree turns in leak path Dh = hydraulic diameter = 4 A/Wp A = flow path cross-section area Wp = wetted perimeter of flow path cross-section area.

(Dh = 7/2 COD for an elliptical crack where COD is the center point crack opening displacement)

For flow through a complex crack consisting of a cracked weld followed by a cracked overlay, there will similarly be losses due to friction and turns. To simulate this in PICEP, an equivalent friction factor must be determined that will yield the same friction as for the complex crack case.

feq(t/Dh) = X fi (Lai/Dh) where fi = friction factor for the revised roughness for each crack face Lai = revised flow path length for each crack face For input to PICEP, the equation above for the friction factor can be used to solve for an equivalent roughness that will produce the correct loss factor.

The equivalent number of turns can be similarly determined.

f (50N 90) = N'i Lai K90 Report No. 0800368.404 B-5

• StructuralIntegrity Associates, Inc.

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where N', = number of 90-degree turns per unit flow path length for each crack face K9 0 = loss coefficient (number of velocity heads) for each 90-degree turn Thus, the number of turns to be used in a PICEP analysis can be determined by:

NpICEP-90 = 0.02 ( N'i Lai K 90 ) /feq where N' = number of 90' turns per inch predicted for a specific crack morphology L = total flow path length = t x KG+iL (from EQ. B-3)

Similarly, the number of 45-degree turns to input in a PICEP run can be determined as:

NpICEP-45 = NpICEP-90 x 50/26 B.3 EFFECT OF CRACK FACE PRESSURE ON LEAKAGE In PICEP, the crack opening area is based on elastic plastic fracture mechanics methods [B-4, page 2-4]. These solutions consider the crack opening from remotely applied loads either due to tension or bending. A method is provided in PICEP so that combined tension and bending can be addressed. The solutions used do not consider the crack opening due to pressure applied on the crack face. The pressure results in both an applied tensile load (FcFp) and an applied moment (MCFP) as described previously. (For input to PICEP, the load equations previously defined must be doubled since the equations were only for one-half pipe sections.)

For PICEP, these loads can be applied as an additional loading added to the remote applied loads that are currently defined as input. With this approach, each PICEP run is only for a specific crack size since the input loading is specific for each crack length. For simplicity, in this evaluation it will be assumed that the crack size in the base metal and in the overlay both have the same crack half angle.

Report No. 0800368.404 B-6 Structural Integrity Associates, Inc.

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1B.3.1 Method for Evaluation Using PICEP

1. A baseline PICEP case is run using the default values for roughness (e.g., 0.000197 inches for fatigue cracks) [B-6] and no turns to simulate fatigue cracking. This run will produce up to twenty leakage calculations for increasing crack size, and report the corresponding COD for each case without the effect of the crack face pressure loads. (This run reads information from a special text input file that was created for a previous PICEP pre-process called RUNPICEP, which was created to ease the creation of input to PICEP - as opposed to the "card" style of input currently required.)

2. A second series of runs is made, one for each of the up to twenty leakage cases above.

For this second set of cases, the axial load and moment loading input is revised to reflect the effects of crack-face pressure. This produces modified crack opening displacement as a function of crack size and actually outputs the leakage flow rate for the original crack parameters for the increased crack opening.

3. For each of the leakage calculations above, the modified parameters to reflect combined fatigue/SCC morphology are calculated, since the modified morphology parameters (number of turns, deviation from straightness and roughness) are functions of COD. The roughness and number of equivalent 45-degree or 90-degree turns to use in PICEP can be calculated using the equations above. Since PICEP accepts only an integer number of turns, the number of 45-degree turns or 90-degree turns that most nearly simulates the total fluid resistance is used. A series of PICEP runs are then made with the revised morphology parameters, with each run being conducted for only the single crack length.

The results for all crack sizes are reported in a single output file.

4. The crack size for any specific leak rate can be determined by interpolation from the modified computer output.

Report No. 0800368.404 B-7 Structural IntegrityAssociates, Inc.

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B.4 REFERENCES B-1. "Probabilistic Pipe Fracture Evaluations for Leak-Rate Detection Applications,"

NUREG/CR-6004, U.S. Nuclear Regulation Commission, April 1995.

B-2. NUREG/CR-6300, "Refinement and Evaluation of Crack-Opening Analyses for Short Circumferential Through-Wall Cracks in Pipes," U.S. Nuclear Regulation Commission, April 1995 B-3. D. Ruland, R. Wolterman, G. Wilkowski, R. Tregoning, "Impact of PWSCC and Current Leak Detection on Leak-Before-Break," Proceedings of Conference on Vessel Head Penetration, Inspection, Cracking, and Repairs, Sponsored by USNRC, Marriot Washingtonian Center, Gaithersburg, MD, September 29 to October 2, 2003.

B-4. D. M. Norris and B. Chexal, "PICEP: Pipe Crack Evaluation Program (Revision 1)," EPRI NP-3596-SR, Revision 1, December 1987.

B-5. SQUIRT (Seepage Quantification of Upsets In Reactor Tubes) User's Manual, Windows Version 1.1, March 24, 2003, Battelle, Columbus, OH.

B-6. D. Abdollahian and B. Chexal, "Calculation of Leak Rates Through Cracks in Pipes and Tubes," EPRI NP-3395, Electric Power Research Institute, Palo Alto, CA, December 1983.

Report No. 0800368.404 B-8 Structural Integrity Associates, Inc.

Revision: 1

KG-Lt T Small COD Figure B-i. Flow Path Deviation As Affected by Roughness and Crack Opening Displacement ILG Large COD AAA~

Small COD Figure B-2. Roughness Depiction for Small and Large Crack Opening Displacements Report No. 0800368.404 B-9 V StructuralIntegrityAssociates, Inc.

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APPENDIX C DETERMINATION OF RAMBERG-OSGOOD PARAMETERS Report No. 0800368.404 C-1 V StructuralIntegrityAssociates, Inc.

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C.1 INTRODUCTION The Ramberg-Osgood (R-O) stress-strain parameters (ox and n) are required for elastic-plastic fracture mechanics analysis involving critical flaw size and leakage determination. These parameters may be a function of temperature. This appendix provides the methodology for determining the R-O parameters from basic mechanical properties determined from the ASME Code. It also includes a method of making adjustment to the R-O parameters at a different temperature when the R-O parameters at another temperature are known.

C.2 METHODOLOGY The Ramberg-Osgood model is in the form:

-- +a (C-i)

Where a and E are the true stress and true strain, co and 6o are the reference stress and reference strain (in general yield stress and yield strain) and a. and n are the Ramberg-Osgood (R-O) parameters.

When the stress-strain curve at the temperature of interest is available, the R-O parameters can be obtained by curve fitting over the strain range of interest. In the absence of the stress-strain curve of the material, a methodology for determining the R-O parameters based on ASME Code-specified mechanical properties has been provided in Ref. C-1. The suggested method is described by the following equations:

0.002 (C-2) ey Report No. 0800368.404 C-2 StructuralIntegrity Associates, Inc.

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n Fi fn(1 + ey)

[,I.e--i ey))

Sy +e)1

-S(1 S=(l~ey) (C-3) iF S,,(1 +e,)

LS, (1+ ey)j where Su and Sy represent ultimate stress and yield stress respectively. They can be obtained from the ASME Code[C-2] for a wide range of temperatures. The yield strain (ey) is determined as:

S ey =sEy (C-4) where E (modulus of elasticity) can also be obtained from the ASME Code. The ultimate strain (e,) is not specified at all temperatures in the ASME Code, hence the room temperature minimum elongation value specified in the ASME Code,Section II [C-2] is assumed for all temperatures. The methodology in any case is not sensitive to the choice of e, [C-i] when determining a and n by using equation (C-2) and (C-3).

C.3 ADJUSTMENT METHODOLOGY As can be seen from Equations C-2 and C-3, a is a function of e, and n is a function of a, eu, ey, S, and Sy, and these properties are a function of temperature. Therefore, an adjustment scheme can be used to adjust the R-O properties known at one temperature based on the specified minimum material properties from the ASME Code. This methodology is used to adjust the R-O properties of thermally aged cast austenitic stainless steel, where the properties at 554°F are obtained from Reference C-3, to the higher Davis-Besse operating temperature of 618'F.

Equation(C - 2) 554 F,Codemin .property (C-5)

Equation(C- 2) 618' F,Codemin.property Report No. 0800368.404 C-3 V Structural IntegrityAssociates, Inc.

Revision: 1

3

) 5541F,Codemin.property (Equation(C (n)6I8oF =(n)se,554oF Equation(C- 3) 618* F,Codemin.property (C-6)

Hence,-Equation (C-2), (C-3), (C-4), (C-5) and (C-6) can be used to obtain R-O parameters at 618'F from the given values at 554°F that were determined to be a = 1.57 and n = 7.37 [C-3].

C.3 REFERENCES C-1 Cofie, N.G., Miessi, G.A., and

Deardorff,

A.F., "Stress-Strain Parameters in Elastic-Plastic Fracture Mechanics," Transactions of the 10th International Conference on Structural Mechanics in Reactor Technology, Volume L - Inelastic Behavior of Metals and Constitutive Laws of Materials, August 14-18, 1989, Anaheim, Ca, USA, pp 91-96.

C-2 ASME Boiler and Pressure Vessel Code, Sections II 2001 Edition with 2003 Addenda.

C-3 NUREG/CR-6142, "Characterization of Thermally Aged Cast Stainless Steels,"

February 1994.

Report No. 0800368.404 C-4 C StructuralIntegrity Associates, Inc.

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Enclosure C L-10-027 Evaluation of Overlay Coverage Approaching 700 Square Inches Based on EPRI 36-inch Diameter Optimized Weld Overlay Mockup; October, 2009 (12 pages follow)

Evaluation of Overlay Coverage Approaching 700 Square Inches Based on EPRI 36-inch Diameter Optimized Weld Overlay Mockup Peter C. Riccardella Structural Integrity Associates October, 2009 1.0 Introduction EPRI (MRP/WRTC) has produced a series of NDE mockups containing flaws that span the exam volume requirement for optimized weld overlays (OWOLs). One of these mockups, a 36" nominal diameter simulated nozzle-to-pipe weld, was also instrumented to determine shrinkage effeats due to the overlay welding process and to confirm the residual stress benefits of the OWOL. The area coverage on the carbon steel side of the overlay approached 700 square inches. The mockup was produced using weld processes typical of reactor coolant loop nozzle fabrication practices. NDE targets were installed, and an inside surface-weld repair during construction was simulated. A weld overlay was applied to the mockup, with dimensions that approximate those of an optimized weld overlay (OWOL) for this size pipe.

Shrinkage measurements were performed for the OWOL using the standard field approach of installing punch marks at four azimuthal locations on either side of the overlay location and accurately measuring the axial length between the punchmarks before and after weld overlay application.

Strain gauge measurements of inside surface residual stresses were also performed using the incremental hole-drilling approach. The residual stress measurements were performed before and after the overlay was applied to the .mockup to determine the benefits of the OWOL. A second form of residual stress measurement, X-ray diffraction (XRD) was also performed for a limited number of confirmatory measurements, after '

application of the OWOL.

This paper presents a description of the mockup and summarizes the shrinkage and residual stress measurements performed-on it.

2.0 -Description .ofMockup The overall layout and dimensions of the mockup are illustrated in Figures 2-1 and 2-2.

The mockup consisted of a cast stainless steel pipe segment, welded to a 450 clad carbon steel elbow, via an Alloy 82/182 DMW. The two pipe segments had 37.4 inch outside diameters, with a 3.37 inch wall thickness. After completing the dissimilar metal butt weld (DMW), a 300 partial arc, inside surface, repair was performed, to a depth of 0.65 inches, to simulate construction repairs that were not uncommon in this vintage of nuclear plants (Figure 2-2). Finally the inside surface counterbore was filled in with Alloy-182 weld metal, as indicated in Figure 2-2. "

A weld overlay was applied to the mockup, with dimensions that approximate those of an optimized weld overlay (OWOL) for this size pipe, although no actual OWOL sizing calculations were performed. The dimensibns of the overlay are indicated in Figure 2-2.

In-process photographs of the weld overlay application are shown in Figure 2-3.

Materials for the various components in the mockup are listed in Table 2-1.

Table Error! No text of specified style in document.-1 EPRI 36". OWOL Mockup Materials.

C6,opo nen. laterial.

.Elbow Carbon Steel (SA-106 Grade B)

Pipe Type 304 Stainless Steel Cladding Type 316L Stainless Steel Butt Weld Alloy 82/1-82 ID Weld Repair Alloy 82/182 Buffer Layer Type 309L WOL Alloy. 52M Of interest in this paper is the coverage area of weld overlay over the carbon steel side of the weld. Utilizing the dimensions in Figures 2-1 and 2-2, this area can be computed as follows:

CS Area Overlaid = 7D(L1 + L2 -L3) where:

L1 6.128" (Length of WOL on CS side of DMW, Fig.- 2-2)

L2 =0.7" (Additional length due to 45° taper, Fig. 2-2)

L3 = 0.532" + 3.37 Tan (100) (OD length ofDMW + butter, Fig. 2-1)

D 37.4" (OD of Pipe).'

The resulting Carbon Steel coverage area is -670 sq. in.

W'ELD PREPAFV 4:1 Figure Error! No text of specified style in document.-I Overall Dimensions of EPRI 36" Diameter OWOL Mockup (Pipe & Elbow OD = 37.4 in.)

Figure Error! No text of specified style in document.-2 Details of ID Repair and Weld Overlay in EPRI 36" Diameter OWOL Mockup

Figure Error! No text of specified style in document.-3 Photographs of EPRI 36" Diameter OWOL Mockup during Weld Overlay Application

3.0 ...Shrinkage Measurements Weld overlay shrinkage measurements were taken on the optimized weld overlay mockup. The shrinkage measurements taken on this mockup are summarized in Table 3-

1. Average shrinkage and rotation are also reported.

Table 3 Axial Shrinkage Measurements on EPRI 36" Diameter Overlay Mockup Axial Shrinkage (in.)

Location from Top Dead 8th Layer Center (Degrees) _

45 -0.014 135 . 0.036

-225 -0.065 315  : 0.053 Ave Shrinkage 0.0025 Computed Rotation . 0.162' The table reports shrinkage measured between punchmarks on either side of the overlay.

at four azimuthal locations around the circumference. Computed averages and rotations are. also reported, in which rotation was computed as the average difference in positive versus negative shrinkage measurements, divided by the pipe diameter and converted to degrees.

The average shrinkage and rotation at the cross section, are negligible for a pipe of this size, and would not produce significant stresses or displacements in a typical PWR large diameter pipe system.

4.0 Residual Stress Measurements and Analyses Residual stresses were also measured on the mockup, pre- and post-weld overlay.

Measurements were made via strain gage hole drilling techniques after completing the.

butt weld, the partial arc ID repair and the counterbore fill-in processes. Axial and hoop stress measurements were taken on the inside surface of the mockup at five axial locations (A through E in Figure 4-1) at several azimuthal locations around the circumference (also illustrated in Figure 4-1). Locations C, D and E are in the PWSCC susceptible material region directly under the DMW, and the 1.800 a7zimuthal location corresponds to the center of the partial arc ID repair. X-ray diffraction (XRD) measurements were also taken at select ID surface locations (post-overlay in the hoop direction only) to provide some confirmation of the strain gage results..

The resulting residual stress measurements are tabulated in Tables 4-1 and 4-2 and are illustrated graphically in Figures 4-2 and 4-3. It is seen from these results that the

OWOL performed quite effectively at reducing the ID surface residual stresses in the PWSCC susceptible material locations (B, C, and D). Axialresidual stresses were reduced from an. average of 74.1 .ksi (pre-overlay) to -0.3 ksi (post overlay) in the regions outside of the ID repair zone (i.e. all azimuths except 180'), and from an average of 94.7 ksi (pre-overlay) to 10.7 ksi (post-overlay) inside the ID repair zone (i.e. at the 1800 azimuth): Hoop residual stresses, were reduced from an average of 64.4 ksi (pre-overlay) to -12.4 ksi (post-overlay) outside of the ID repair zone, and from an average of 88 ksi (pre-overlay) to 22 ksi (post-overlay) inside theID repair zone.. The OWOL thus achieved approximately 70 ksi of stress improvement at all locations. The XRD measurements were in reasonably agreementwith the straingage data, within typical experimental error bands, for these types of measurements..

It is noteworthy that, although the absolute residual stress results did not fully satisfy MRP-169 residual stress criteria (less than 10 ksi tensile on the ID surface), the starting residual stresses were very severe compared to typical field overlay applications, because of the combined effects of the partial arc ID surface repair followed by the counterbore fill-in step, which constituted effectively a second, 360' repair. The mockup also did not simulate a stainless steel pipe to safe-end weld, which exists in many -field applications, and which is known to have a favorable effect on pre-overlay residual stresses. 70 ksi

' residual stress improvement is more than adequate for most, if not all, field OWOL applications.

.Finally, it is noteworthy in the context of this paper that, based on analyses, increasing the coverage area of weld overlays is expected to improve, not degrade, their residual stress performance.

Table 4 Strain Gage Residual Stress Measurements on EPRI 36" Diameter OWOL Mockup (Stresses in ksi)

Case Location 30 900 150' i80' 2100 2700. 330° Axial; Pre- A 20 31 28. *, 32 25 27 OWOL. B 68 77 81 110 80 76 59 C .73 70 75 90

• 72 64 69 D 61 .77 67 84 79 102 83 E 34 46 52 ,, 39 -14 40 Axial; Post- A 0 .3 2 4 6 1 OWOL . B -5. -3 . 7 <12 12 -1 -3 C -4 -7 6 11: 4 0 -5 D -9 6 '9 5 -2 -6 E 2 3 5 9 5 3 Hoop; Pre- A 24 33 42 .30 33 37 OWOL B 62 59 70 :82 67 50 51 C 71 66 83 92', 75 87 :60 D 70 68 79 90 47 31 64 E 39 40 55 . 44 -11 .47 Hoop; Post- ..A -9 -7 15 -6 -1 -4 OWOL B -18 -12 -3 25" -15 , -13 _-17 C -32 -1.9 -2 221 -12 -15 -21 D-3, -16 8...19. -18 -6 -9.

E 10-4 Az-2. is a-5 20 0 1 Note: 1800 Azimuth is at center of ID repair location Table 4 X-ray Diffraction Residual Stress Measurements on EPRI 36" Diameter OWOL Mockup (Stresses in ksi)

Note: 1800 Azimuth is at center 'ofID repair location-

A-C 6.0 inches CAST OVERLAY DESIGN B-C 0.67 inches D-C 0.67 inches 6.0 inches A COD E 900 15500 300 1800

)3300 306 partial arc ID repair centered at 1800,;

Entire counterbore then 2700 filled in 3600 Figure 4-1 Residual Stress Measurement Locations

1 120 . .

• Measured Pre-WOL 30.

ia Measured Pre-WOL 90' 100___ ___ _ _

E]Measured Pre-WOL.I50' 80 '-' Pre-OWOL '

A Measured Pre-WOL 180' Measure. "

• Measured Pre-WOL 210' 60-Z A Measured Pre-WOL 270' A Measured Pre-WOL 330°

'a ~40___ ___

0 Measured Post-WOL 30*

a))

0 Measured Post-WOL 90' 10 U Measured Post-WOL 150' 0 Post o.i-WOL P o A Measured Pbst-WOL 180° 0 Measured Post-WOL 210'

-20 ___ ~ +

0 Measured Post-WOL 270° A Measured Post-WOL 330'

-~ ~ ___ - ___ ___

.-6 -5 -4 -3 -2 -1 0 1 2 3 -4 5 6 Axial Distance Along IDSurface (in)

Figure 4-2

,EPRI 36" Mockup Axial Residual Stress Measurements

120

• Measured Pre-WOL 30

',Measured Pre-WOL 90" 10Measured Pre-WOL 150'

• A Measured Pre-WOL 180*

Pre-OWOL Measured Pre-W OL210 ° 80

, Measured Pre-WOL 2703 60 A Measured Pre-WOL 330' 0U*Measured Measure.d Post WOL 30o Post-WOL 90' w -

• 0_ _ Measured Post-WOL 150*

aX A Measured Post-WOL 180O C. 0 Measured Post-WOL 21o0 20 Post-OWO L *OMeasuredPost-WOL 270' A Measured Post-WOL 3310

... __ _ _ X XRD Post-WOL 10 0

X XRD Pust-WOL 60'

-XRD Pust WOL 125*

-.20 XXRD Post-WOL 18o*

+ XRD Post-WOL 235"

-40 -XRD Post-WOL 280°

-6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 Axial Distance Along ID Surface (in)

Figure 4-3 EPRI 36" Mockup Hoop Residual Stress Measurements

5.0 Conclusions An optimized weld overlay mockup with carbon steel coverage area approaching 700

• squareinches (-670 sq. in) has been performed as part of the EPRI(MRP/WRTC) program to produce samples for the NDE qualification' program. In addition to its use for NDE purposes, this mockup was also instrumented to measure axial shrinkage and.

residual stress effects of the weld overlay. The mockup showed that a weld overlay with this amount of carbon steel coverage experienced negligible shrinkage effects, and that the overlay performed quite effectively in terms of reducing very high inside surface pre-overlay residual stresses in the mockup (average residual stress benefit on the Order of 70 ksi). It is also noted that increasing the size of this overlay, and thus the amount of carbon steel coverage, would be expected based on analysis to improve the residual stress performance.

Enclosure D L-1 0-027 Affidavits Structural Integrity Associates, ,Inc. and AREVA NP, Inc.

(5 pages follow)

StructuralIntegrity Associates, Inc.

5215 Hellyer Ave.

Suite 210 San Jose, CA 95138-1025 Phone: 408-978-8200-Fax' . 408-978-8964 www.structintcom.

January 12, 2010 AFFIDAVIT I, Marcos Legaspi Herrera, state as follows:

(1) I amna Vice President of Structural Integrity Associates, Inc. (SI) and have been delegated the function of reviewing the information described in paragraph (2) which is sought to be withheld, and have been authorized to apply for its withholding.

(2) The information sought to be withheld is contained in SI Report 0800368.404, Rev. 1, "Leak-Before-Break Evaluation of Reactor Coolant Pump Suction and Discharge Nozzle Weld Overlays for Davis-Besse Nuclear Power Station." This Report is to be treated as SI proprietary information, because it contains significant information that is deemed proprietary and confidential to AREVA N7P. AREVA NP design input information was provided to SI in strictest confidence so hat we could generate the aforementioned Report on behalf of SI's client, FirstEnergy Nuclear Operating Company (FENOC).

Paragraph 3 of this Affidavit provides the basis for the proprietary determination.

(3) SI is making this application for withholding of proprietary information on the basis that such information was provided to SI under the protection of a Proprietary/Confidentiality and Nondisclosure Agreement between SI and AREVA NP. In a separate Affidavit requesting withholding of such proprietary information prepared by AREVA NP, AREVA NP relies upon the exemption of disclosure set forth in NRC Regulation 10 CFR 2.390(a)(4) pertaining to "trade secrets and commercial or financial information obtained from a person and privileged or confidential" (Exemption 4). As delineated in AREVA NP' s Affidavit, the. material for which exemption from disclosure is herein sought is' considered proprietary for the following reasons (taken directly from Items. 6(b) and 6(c) of AREVA NP's Affidavit):.

a) Use of the information by a competitor would permit the competitor to significantly reduce its expenditures, in time or resources, to design, produce, or market a similar product or service; and

SI Affidavit for Report 0800368.404, Rev. 1 January 12, 2010, Page 2 of 2 b) The information includes test data or analytical techniques concerning a process, methodology, or component, the application of which results in a competitive advantage for AREVA NP.

Public disclosure of the information sought to be withheld is likely to cause substantial harm to AREVA NP with which SI has established a Proprietary/Confidentiality and Nondisclosure Agreement.

I declare under penalty of perjury that the above information and request-are true, correct, and complete to the best of my knowledge, information, and belief.

Executed at San Jose, California on this 12th day of January, 2010.

" >6.K" -)A 15 Mgcos Legaspi Herrera,, P.E.

Vice President Nuclear Plant Services State of California Subscribed and sworn to (or affirmed) before me County ofS CL {§- onthis IJ- day of -' caUt ,20/0 Date Montf, Year by

-UNamb of Signer proved to me on the basis of satisfactory evidence to be the person who appeared before me (.)

(and

1. 1866327T 1 C.METZGER Commission Notary Public - California z (2) ---

z Santa Clara County z Name of Signer P mmExpires Se A7o2e proved to me on the basis of satisfactory evidence to be the person who appeared before me.)

Signature Place Notary Seal and/or Stamp Above O StructuralIntegrity Associates, Inc.

AFFIDAVIT COMMONWEALTH OF VIRGINIA )

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CITY OF LYNCHBURG )

1. My name is Gayle F. Elliott. I am Manager, Product Licensing, for AREVA NP Inc. and as such I am authorized to execute this Affidavit.

2. inam familiar with the criteria applied by AREVA NP to determine whether certain AREVA NP information is proprietary. I am familiar with the policies established by' AREVA NP to ensure the proper application of these criteria.

3. I am familiar with the AREVA NP information contained in Structural Integrity Associates, Inc. Report No. 0800368.404, Revision 1, entitled "Leak-Before-Break Evaluation of Reactor Coolant Pump Suction and Discharge Nozzle Weld Overlays for Davis-Besse Nuclear Power Station," dated January 2010 and referred to herein as "Document." Information contained in this Document has been classified by AREVA NP as proprietary in accordance with the policies established by AREVA NP for the control and protection of proprietary and confidential information.

4. This Document contains information of a proprietary and confidential nature and is of the type customarily held in confidence by AREVA NP and not made available to the public. Based on my experience, I am aware that other companies regard information of the kind contained in this Document as proprietary and confidential.

'5. This Document has been made available to the U.S. Nuclear Regulatory Commission in confidence with the request that the information contained in this Document be withheld from public disclosure. The request for withholding of proprietary information is made in

accordance with 10 CFR 2.390. The information for which withholding from disclosure is.

requested qualifies under 10 CFR 2.390(a)(4) "Trade secrets and commercial or financial information."

6. 'The following criteria are customarily applied by AREVA NP to determine whether information should be classified as proprietary:

(a) The information reveals details of AREVA NP's research and development plans and programs or their results.

(b) Use of the information by a competitor would permit the competitor to significantly reduce its expenditures, in time or resources, to design, -produce, or market a similar product or service.

(c) The information includes test data or analytical techniques concerning a process, methodology, or component, the application of which results in a competitive, advantage for AREVA NP.

(d) The information reveals certain distinguishing aspects of a process, methodology, or component, the exclusive use of which provides a competitive advantage for AREVA NP in product optimization or marketability.

(e) The information is vital to a competitive advantage held by AREVA NP, would be helpful to. competitors to AREVA NP, and would likely cause substantial harm to the competitive position of AREVA NP.

The information in the Document is considered proprietary for the reasons set forth in paragraphs 6(b) and 6(c) above.

7. In accordance with AREVA NP's .policies governing the protection and control of information, proprietary information contained in this Document have been made available, on a limited basis, .to others outside AREVA NP only as required and under suitable agreement providing for nondisclosure and limited use of the information.

8. AREVA NP policy requires that proprietary information be kept in a secured file or area and distributed on a need-to-know basis.

9. "The foregoing statements are true and correct to the best of my knowledge, information, and belief.

SUBSCRIBED before me this ,94 day of*//

• 2010.

Sherry L. McFaden NOTARY PUBLIC, COMMONWEALTH OF VIRGINIA MY COMMISSION EXPIRES: 10/31/10 Reg. #7079129 SHEIRV L.MCPADEN CmNwoltar of VIrgni Nom onwatary Pub f gln 7079129 C wmminlon I ! pifes Oct 31.20