ML20149K671

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PWROG-19047-NP, Revision 0, North Anna, Units 1 and 2, Reactor Vessels Low Upper-Shelf Fracture Toughness Equivalent Margin Analysis
ML20149K671
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Site: North Anna, PROJ0694, 99902037  Dominion icon.png
Issue date: 05/31/2020
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OG-20-167, PA-MSC-1481, Rev 3 PWROG-19047-NP, Rev 0
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Westinghouse Proprietary Class 2 PWROG-19047-NP Revision 0 WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY North Anna Units 1 and 2 Reactor Vessels Low Upper-Shelf Fracture Toughness Equivalent Margin Analysis Materials Committee PA- MSC-1481, R3 May 2020

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY PWROG-19047-NP Revision 0 North Anna Units 1 and 2 Reactor Vessels Low Upper-Shelf Fracture Toughness Equivalent Margin Analysis PA- MSC-1481, R3 Gordon Z. Hall

  • Structural Design and Analysis May 2020 Reviewer: Jay D. White*

Structural Design and Analysis Reviewer: Ashok D. Nana Framatome, Component Analysis and Fracture Mechanics Approved: Stephen P. Rigby*, Manager Structural Design and Analysis Approved: Jim Molkenthin*, Program Director PWR Owners Group PMO This document may contain technical data subject to the export control laws of the United States. In the event that this document does contain such information, the Recipients acceptance of this document constitutes agreement that this information in document form (or any other medium), including any attachments and exhibits hereto, shall not be exported, released or disclosed to foreign persons whether in the United States or abroad by recipient except in compliance with all U.S. export control regulations. Recipient shall include this notice with any reproduced or excerpted portion of this document or any document derived from, based on, incorporating, using or relying on the information contained in this document.

This document contains information that is the property of Westinghouse Electric Company LLC and its affiliates (Westinghouse) or Framatome Inc. and its affiliates (Framatome). This document is to be considered proprietary to Westinghouse and Framatome and may not be reproduced or copied in whole or in part without the express, written consent of Westinghouse and Framatome. This document shall not be furnished to others without the express written consent of Westinghouse and Framatome and is not to be used in any way which is or may be detrimental to Westinghouse or Framatome. This document and any copies that may have been made must be returned to Westinghouse or Framatome upon request.

  • Electronically approved records are authenticated in the electronic document management system.

Westinghouse Electric Company LLC 1000 Westinghouse Drive Cranberry Township, PA 16066, USA

© 2020 Westinghouse Electric Company LLC All Rights Reserved Framatome Inc.

3315 Old Forest Road Lynchburg, VA 24501 PWROG-19047-NP_Revision_0.docx-052620

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY iii ACKNOWLEDGEMENTS This topical report was developed and funded by the PWR Owners Group under the leadership of the participating utility representatives of the Materials Committee. The author would like to thank the following people and/or organizations for their valuable contributions to this report:

Mark Rinckel, Framatome Martin Kolar, Framatome Chuck Tomes, Dominion PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY iv LEGAL NOTICE This report was prepared as an account of work performed by Westinghouse Electric Company LLC and Framatome Inc. Neither Westinghouse Electric Company LLC nor Framatome Inc. nor its affiliates, nor any person acting on its behalf:

Makes any warranty or representation, express or implied including the warranties of fitness for a particular purpose or merchantability, with respect to the accuracy, completeness, or usefulness of the information contained in this report, or that the use of any information, apparatus, method, or process disclosed in this report may not infringe privately owned rights; or Assumes any liabilities with respect to the use of, or for damages resulting from the use of, any information, apparatus, method, or process disclosed in this report.

COPYRIGHT NOTICE This report has been prepared by Westinghouse Electric Company LLC and bears a Westinghouse Electric Company copyright notice. Information in this report is the property of and contains copyright material owned by Westinghouse Electric Company LLC and /or its subcontractors and suppliers. It is transmitted to you in confidence and trust, and you agree to treat this document and the material contained therein in strict accordance with the terms and conditions of the agreement under which it was provided to you.

This report has been reviewed by Framatome Inc. and bears a Framatome Inc. copyright notice.

Information in this report is the property of and contains copyright material owned by Framatome Inc. and /or its subcontractors and suppliers. It is transmitted to you in confidence and trust, and you agree to treat this document and the material contained therein in strict accordance with the terms and conditions of the agreement under which it was provided to you.

As a participating member of this task, you are permitted to make the number of copies of the information contained in this report that are necessary for your internal use in connection with your implementation of the report results for your plant(s) in your normal conduct of business.

Should implementation of this report involve a third party, you are permitted to make the number of copies of the information contained in this report that are necessary for the third partys use in supporting your implementation at your plant(s) in your normal conduct of business if you have received the prior, written consent of Westinghouse Electric Company LLC to transmit this information to a third party or parties. All copies made by you must include the copyright notice in all instances and the proprietary notice if the original was identified as proprietary.

PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY v DISTRIBUTION NOTICE This report was prepared for the PWR Owners Group. This Distribution Notice is intended to establish guidance for access to this information. This report (including proprietary and non-proprietary versions) is not to be provided to any individual or organization outside of the PWR Owners Group program participants without prior written approval of the PWR Owners Group Program Management Office. However, prior written approval is not required for program participants to provide copies of Class 3 Non-Proprietary reports to third parties that are supporting implementation at their plant, and for submittals to the NRC.

PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY vi PWR Owners Group United States Member Participation* for PA- MSC-1481, R3 Participant Utility Member Plant Site(s) Yes No Ameren Missouri Callaway (W) X American Electric Power D.C. Cook 1 & 2 (W) X Arizona Public Service Palo Verde Unit 1, 2, & 3 (CE) X Millstone 2 (CE) X Millstone 3 (W) X Dominion Energy North Anna 1 & 2 (W) X Surry 1 & 2 (W) X V.C. Summer (W) X Catawba 1 & 2 (W) X Duke Energy Carolinas McGuire 1 & 2 (W) X Oconee 1, 2, & 3 (B&W) X Robinson 2 (W) X Duke Energy Progress Shearon Harris (W) X Entergy Palisades Palisades (CE) X Entergy Nuclear Northeast Indian Point 2 & 3 (W) X Arkansas 1 (B&W) X Entergy Operations South Arkansas 2 (CE) X Waterford 3 (CE) X Braidwood 1 & 2 (W) X Byron 1 & 2 (W) X Exelon Generation Co. LLC Calvert Cliffs 1 & 2 (CE) X Ginna (W) X Beaver Valley 1 & 2 (W) X FirstEnergy Nuclear Operating Co.

Davis-Besse (B&W) X St. Lucie 1 & 2 (CE) X Turkey Point 3 & 4 (W) X Florida Power & Light \ NextEra Seabrook (W) X Pt. Beach 1 & 2 (W) X Luminant Power Comanche Peak 1 & 2 (W) X PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY vii PWR Owners Group United States Member Participation* for PA- MSC-1481, R3 Participant Utility Member Plant Site(s) Yes No Pacific Gas & Electric Diablo Canyon 1 & 2 (W) X PSEG - Nuclear Salem 1 & 2 (W) X So. Texas Project Nuclear Operating Co. South Texas Project 1 & 2 (W) X Farley 1 & 2 (W) X Southern Nuclear Operating Co.

Vogtle 1 & 2 (W) X Sequoyah 1 & 2 (W) X Tennessee Valley Authority Watts Bar 1 & 2 (W) X Wolf Creek Nuclear Operating Co. Wolf Creek (W) X Xcel Energy Prairie Island 1 & 2 (W) X

  • Project participants as of the date the final deliverable was completed. On occasion, additional members will join a project. Please contact the PWR Owners Group Program Management Office to verify participation before sending this document to participants not listed above.

PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY viii PWR Owners Group International Member Participation* for PA- MSC-1481, R3 Participant Utility Member Plant Site(s) Yes No Asco 1 & 2 (W) X Asociación Nuclear Ascó-Vandells Vandellos 2 (W) X Centrales Nucleares Almaraz-Trillo Almaraz 1 & 2 (W) X EDF Energy Sizewell B (W) X Doel 1, 2 & 4 (W) X Electrabel Tihange 1 & 3 (W) X Electricite de France 58 Units X Elektriciteits Produktiemaatschappij Zuid- Borssele 1 (Siemens) X Nederland Eletronuclear-Eletrobras Angra 1 (W) X Emirates Nuclear Energy Corporation Barakah 1 & 2 X Hokkaido Tomari 1, 2 & 3 (MHI) X Japan Atomic Power Company Tsuruga 2 (MHI) X Mihama 3 (W) X Kansai Electric Co., LTD Ohi 1, 2, 3 & 4 (W & MHI) X Takahama 1, 2, 3 & 4 (W & MHI) X Kori 1, 2, 3 & 4 (W) X Hanbit 1 & 2 (W) X Korea Hydro & Nuclear Power Corp.

Hanbit 3, 4, 5 & 6 (CE) X Hanul 3, 4 , 5 & 6 (CE) X Genkai 2, 3 & 4 (MHI) X Kyushu Sendai 1 & 2 (MHI) X Nuklearna Electrarna KRSKO Krsko (W) X Ringhals AB Ringhals 2, 3 & 4 (W) X Shikoku Ikata 2 & 3 (MHI) X Taiwan Power Co. Maanshan 1 & 2 (W) X

  • Project participants as of the date the final deliverable was completed. On occasion, additional members will join a project. Please contact the PWR Owners Group Program Management Office to verify participation before sending this document to participants not listed above.

PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY ix TABLE OF CONTENTS 1 INTRODUCTION ............................................................................................................ 1-1

2 REGULATORY REQUIREMENTS ................................................................................. 2-1

2.1 REGULATORY REQUIREMENTS ..................................................................... 2-1

2.2 COMPLIANCE WITH 10 CFR 50 APPENDIX G AND ACCEPTANCE CRITERIA ........................................................................................................... 2-2

2.2.1 Acceptance Criteria ............................................................................. 2-2

3 EQUIVALENT MARGINS ANALYSIS INPUTS ............................................................... 3-1

3.1 FINITE ELEMENT STRESS ANALYSIS ............................................................. 3-1

3.2 J-INTEGRAL RESISTANCE MODELS ............................................................... 3-4

4 FRACTURE MECHANICS ANALYSIS ........................................................................... 4-1

4.1 METHODOLOGY DISCUSSION ........................................................................ 4-1

4.1.1 Nozzle-to-Shell Welds and Upper Shell Forging, KI Using A-3200

[8] ......................................................................................................... 4-1

4.1.2 Nozzle Corner KI Closed Form Solution per [11] ................................. 4-3

4.1.3 Calculation of Japplied for Small-Scale Yielding ...................................... 4-4

4.1.4 Postulated Flaw ................................................................................... 4-4

4.1.5 Weld Residual Stress .......................................................................... 4-4

4.1.6 Stress Due to Mechanical Loads ......................................................... 4-5

4.1.7 Temperature Range for Upper Shelf Fracture Toughness Evaluations .......................................................................................... 4-5

4.2 APPLIED J-INTEGRAL RESULTS AND COMPARISON WITH J-R CURVES ALLOWABLES .................................................................................... 4-6

4.2.1 Nozzle-to-Shell Welds Level A/B ......................................................... 4-6

4.2.2 Nozzle-to-Shell Welds Level D ............................................................ 4-8

4.2.3 Upper Shell Forging Level A/B........................................................... 4-15

4.2.4 Upper Shell Forging Level D.............................................................. 4-17

4.2.5 Nozzle Forging Level A/B .................................................................. 4-20

4.2.6 Nozzle Forging Level D ..................................................................... 4-24

5 CONCLUSIONS ............................................................................................................. 5-1

6 REFERENCES ............................................................................................................... 6-1

PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY x LIST OF TABLES Table 3-1: Base Metal Material Properties (SA-508 Class 2) ..................................................... 3-3

Table 3-2: Cladding Material Properties (Type 304 Stainless Steel) .......................................... 3-3

Table 3-3: J-R Calculation Input Parameters for Nozzle Welds ................................................. 3-4

Table 3-4: Model 6B J-R curve for Nozzle-to Shell Welds at 552°F for Levels A/B................... 3-4

Table 3-5: Parameters for RPV Base Metals, Jd Model [3, Table 11] ......................................... 3-6

Table 3-6: RV Inlet and Outlet Nozzle Forgings J-R Curves ..................................................... 3-6

Table 3-7: RV Intermediate Shell Forgings J-R Curves ............................................................ 3-7

Table 4-1: Inlet and Outlet Nozzle Welds Levels A/B, Circumferential Flaw, Japplied ................... 4-6

Table 4-2: Inlet and Outlet Nozzle Welds Level D, Circumferential Flaw, Limiting Japplied........... 4-9

Table 4-3: B&WOG Model 6-B Mean J-R Curve with a = 0.1 inch ........................................ 4-10

Table 4-4: KIc2/E Curve ............................................................................................................ 4-10

Table 4-5: K-5300 Tensile Instability Check for RV Nozzle-to-Shell Weld ................................ 4-15

Table 4-6: Upper Shell Forging Level A/B, Circumferential Flaw, Limiting Japplied ..................... 4-15

Table 4-7: Upper Shell Forging Level D, Limiting Japplied .......................................................... 4-18

Table 4-8: K-5300 Tensile Instability Check for RV Upper Shell .............................................. 4-19

Table 4-9: Nozzle Corner Level A/B, Limiting Japplied ................................................................ 4-20

Table 4-10: Nozzle Corner Level D, Limiting Japplied ................................................................. 4-25

Table 4-11: K-5300 Tensile Instability Check for RV Nozzle Corner ........................................ 4-29

PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY xi LIST OF FIGURES Figure 3-1: North Anna Units 1 and 2 Reactor Vessel Generic Configuration ........................... 3-1

Figure 3-2: Overview of FEM ..................................................................................................... 3-2

Figure 4-1: KI Solution for Quarter Circular Crack in Quarter Space [11, page 5]...................... 4-3

Figure 4-2: Inlet Nozzle Weld, Circumferential Flaw, Levels A/B Japplied vs. J-R, SF=1.25 ......... 4-7

Figure 4-3: Outlet Nozzle Weld, Circumferential Flaw, Levels A/B Japplied vs. J-R, SF=1.25 ...... 4-8

Figure 4-4: Inlet Nozzle-to-Shell Weld, J-integral vs. Temperature .......................................... 4-11

Figure 4-5: Inlet Nozzle-to-Shell Weld, J-integral vs. Flaw Extension...................................... 4-12

Figure 4-6: Outlet Nozzle-to-Shell Weld, J-integral vs. Temperature ....................................... 4-13

Figure 4-7: Outlet Nozzle-to-Shell Weld, J-integral vs. Flaw Extension ................................... 4-14

Figure 4-8: RV Upper Shell, Circumferential Flaw, Level A/B Japplied vs. J-R, SF=1.25 ............ 4-16

Figure 4-9: RV Upper Shell, Axial Flaw, Level A/B Japplied vs. J-R, SF=1.25 ............................. 4-17

Figure 4-10: RV Upper Shell, Circumferential Flaw, Level D Japplied vs. J-R ............................. 4-18

Figure 4-11: RV Upper Shell, Axial Flaw, Level D Japplied vs. J-R .............................................. 4-19

Figure 4-12: Inlet Nozzle Corner, Circumferential Flaw, Level A/B Japplied vs. J-R, SF=1.25 .... 4-21

Figure 4-13: Outlet Nozzle Corner, Circumferential Flaw, Level A/B Japplied vs. J-R, SF=1.25 . 4-22

Figure 4-14: Inlet Nozzle Corner, Axial Flaw, Level A/B Japplied vs. J-R, SF=1.25 ..................... 4-23

Figure 4-15: Outlet Nozzle Corner, Axial Flaw, Level A/B Japplied vs. J-R, SF=1.25 .................. 4-24

Figure 4-16: Inlet Nozzle Corner, Circumferential Flaw, Level D Japplied vs. J-R, SF=1.0 ......... 4-26

Figure 4-17: Outlet Nozzle Corner, Circumferential Flaw, Level D Japplied vs. J-R, SF=1.0 ...... 4-27

Figure 4-18: Inlet Nozzle Corner, Axial Flaw, Level D Japplied vs. J-R, SF=1.0 .......................... 4-28

Figure 4-19: Outlet Nozzle Corner, Axial Flaw, Level D Japplied vs. J-R, SF=1.0 ....................... 4-29

PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 1-1 1 INTRODUCTION The purpose of this topical report is to document the equivalent margins analysis (EMA) for the North Anna Units 1 and 2 reactor vessel (RV) inlet and outlet nozzle Rotterdam welds, nozzle forgings and nozzle belt forgings (a.k.a., upper shell forgings). These locations were chosen for their upper-shelf energy (USE) potentially falling below the 50 ft-lb limit at 80-years (72 EFPY) for subsequent license renewal (SLR). Materials with end-of-license-extension (EOLE) USE below the 50 ft-lb limit are required to be evaluated per paragraph IV.A.1.a of 10 CFR 50, Appendix G, for equivalent margins of safety specified in ASME Code Section XI, Appendix K [8].

The North Anna Units 1 and 2 reactor vessels are Westinghouse-designed vessels whose subject nozzle welds were fabricated by the Rotterdam Shipyards. There are only two locations with projected SLR USE at or below the required 50 ft-lbs:

x North Anna Unit 1, Inlet Nozzle Forging 11, Heat #990268-21 x North Anna Unit 2, Intermediate Shell Forging 04, Heat #990496 / 292424 The EMA for the nozzle and upper shell forgings utilizes the multivariable model for RV base metal reported in NUREG/CR-5729. Although the Rotterdam nozzle-to-shell welds are projected to have USE greater than 50 ft-lbs, they are evaluated proactively in this EMA for asset management consideration. The EMA for the Rotterdam welds utilizes the B&WOG J-integral resistance (J-R) Model 6B reported in BAW-2192, Revision 0, Supplement 1P-A, Rev. 0, Appendix A [1]. The justification for using the B&WOG Model 6B for the North Anna Rotterdam welds is addressed in BAW-2192, Supplement 2P, Revision 0 [2].

This low upper-shelf toughness EMA is based on the projected RV neutron fluence at 80 years of operation for SLR at the RV inlet and outlet nozzle regions, which are projected to exceed 1.0 E+17 n/cm2, E > 1.0 MeV, and are qualified as extended beltline materials. The general configuration of the North Anna Units 1 and 2 RVs, and the locations evaluated in this EMA are shown in Figure 3-1. There are no longitudinal welds on the North Anna Units 1 and 2 RVs.

PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 2-1 2 REGULATORY REQUIREMENTS 2.1 REGULATORY REQUIREMENTS In accordance with 10 CFR 50, Appendix G, IV.A.1, [4] Reactor Vessel Upper Shelf Energy Requirements are as follows.

(a) Reactor Vessel beltline materials must have Charpy upper-shelf energy in the transverse direction for base material and along the weld for weld material according to the ASME Code, of no less than 75 ft-lb (102 J) initially and must maintain Charpy upper-shelf energy throughout the life of the vessel of no less than 50 ft-lb (68 J), unless it is demonstrated in a manner approved by the Director, Office of Nuclear Reactor Regulation or Director, that lower values of Charpy upper-shelf energy will provide margins of safety against fracture equivalent to those required by Appendix G of Section XI of the ASME Code. This analysis must use the latest edition and addenda of the ASME Code incorporated by reference into 10 CFR 50.55a (b)(2) at the time the analysis is submitted.

(b) Additional evidence of the fracture toughness of the beltline materials after exposure to neutron irradiation may be obtained from results of supplemental fracture toughness tests for use in the analysis specified in section IV.A.1.a.

(c) The analysis for satisfying the requirements of section IV.A.1 of this appendix must be submitted, as specified in § 50.4, for review and approval on an individual case basis at least three years prior to the date when the predicted Charpy upper-shelf energy will no longer satisfy the requirements of section IV.A.1 of this appendix, or on a schedule approved by the Director, Office of Nuclear Reactor Regulation.

When the RVs within the scope of this topical report were fabricated, the Charpy V-notch testing of the RV welds was in accordance with the original construction code, which did not require Charpy V-notch tests on the upper shelf. The original construction code for the RV shell and nozzles for both units is ASME Section III, 1968 Edition through the Winter 1968 Addenda, as discussed in the North Anna Units 1 and 2 Updated Final Safety Analysis Report (UFSAR) [5, Table 5.2-3].

In accordance with NRC Regulatory Guide 1.161 [6], the NRC has determined that the analytical methods described in ASME Section XI, Appendix K, provide acceptable guidance for evaluating reactor pressure vessels when the Charpy USE falls below the 50 ft-lb limit of Appendix G of 10 CFR Part 50. However, the staff noted that Appendix K does not provide information on the selection of transients and provides very little detail on the selection of material properties.

Consistent with BAW-2192, Revision 0, Supplement 1P-A, Revision 0 [1], the cooldown transient for North Anna Units 1 and 2 with a constant pressure of 2750 psia assumed throughout the transient bounds all Levels A/B conditions. This is consistent with and based on the ASME Section XI, Appendix K 100°F/hour cooldown rate guidance coincident with the use of a high pressure value. The Level C/D transient selection is based on the guidance in Regulatory Guide PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 2-2 1.161 Section 4.0 [6]. There are no applicable emergency (Level C) transients in the RV design specifications. The Level D transient is the steam line break (SLB). Additional transient discussions are contained in Section 4.1. Physical properties for the forging and weld materials are from construction ASME Code [7]. The J-Resistance (J-R) models are discussed in detail in Section 3.2.

2.2 COMPLIANCE WITH 10 CFR 50 APPENDIX G AND ACCEPTANCE CRITERIA The analyses reported herein are performed in accordance with the 2013 Edition of Section XI of the ASME Code, Appendix K [8]. The edition of ASME Section XI discussed in 10 CFR 50.55a is the 2013 Edition. The material properties used in this analysis are based on the original RV construction code, ASME Boiler and Pressure Vessel Code,Section III, 1968 Edition, with Addenda up to and including the Winter of 1968 [7].

2.2.1 Acceptance Criteria ASME Section XI [8], Appendix K provides the acceptance criteria for the Level A, B, C and D conditions. These criteria summarized in the following subsections are consistent with Regulatory Guide 1.161.

2.2.1.1 K-2200 Levels A and B Service Loadings (a) Postulated axial and circumferential flaws are interior semi-elliptical surface flaws with a depth of 1/4 of the wall thickness and a length to depth (l/a) aspect ratio of 6.

(1) Japplied with a SF of 1.15 for pressure and a SF of 1.0 for thermal (cooldown) shall be less than the J-integral of the material (J-R curve) at a ductile flaw extension of 0.1 inch.

(2) Japplied with a SF of 1.25 for pressure and a SF of 1.0 for thermal (cooldown) shall be ductile and stable.

(b) The J-R curve shall be a conservative representation for the vessel material under evaluation.

The flaw stability criteria is per K-3400: at J

  • JR. This is further explained in K-4310.

The J-R curve shall be plotted on the crack driving force diagram and shall intersect the horizontal axis at the initial flaw depth, a0. Flaw stability at a given applied load is verified when the slope of the Japplied curve is less than the slope of the J-R curve at the point on the J-R curve where the two curves intersect.

PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 2-3 2.2.1.2 K-2300 and K-2400, Levels C and D Service Loadings Per K-2400, the Level D postulated flaws shall be the same as those specified for Level C in K-2300.

(a) Postulated axial and circumferential flaws are interior semi-elliptical surface flaws with depths up to 1/10 of the wall thickness of the base metal plus cladding, with total depth not exceeding 1 inch. For cases where 1/10 wall thickness plus cladding exceeded 1 inch, 1 inch is used for the postulated flaws for Level D. The length to depth (l/a) aspect ratio is 6.

(1) Japplied with a SF of 1.0 for thermal and pressure shall be less than the J-R curve at a ductile flaw extension of 0.1 inch.

(2) Japplied with a SF of 1.0 for thermal and pressure shall be ductile and stable.

(b) The J-R curve shall be a conservative representation for the vessel material under evaluation.

(c) The total flaw depth after stable flaw extension shall be less than or equal to 75% of the vessel wall thickness, and the remaining ligament shall not be subject to tensile instability.

The flaw stability criteria is detailed in K-5300.

(a) Stability is verified per K-3400: at J

  • JR.

(b) For Level D Service Loadings, demonstrate that total flaw depth after stable flaw extension is less than or equal to 75% of the vessel wall thickness, and the remaining ligament is not subjected to tensile instability. The internal pressure shall be less than the instability pressure (PI), calculated by the equations below:

/

(1) For axial flaw, 1.07

/

(2) For circumferential flaw, 1.07 PI is limited to 1.07 PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 2-4 where, o = Flow stress, average of yield strength and ultimate tensile strength A = An area parameter = t (l + t)

Ac = Area of the flaw = al / 4 Ri = Inner radius of the vessel Rm = Mean radius of the vessel t = Wall thickness of the vessel a = Flaw Depth l = Flaw length PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 3-1 3 EQUIVALENT MARGINS ANALYSIS INPUTS 3.1 FINITE ELEMENT STRESS ANALYSIS The general procedures for J-integral calculation are described in Appendix K of [8]. As discussed in Section 2.1, the cooldown transient was analyzed to bound Levels A/B. The Level D transient is SLB. Figure 3-1 is a sketch illustrating the North Anna RV upper shell, intermediate shell, inlet and outlet nozzles, and nozzle to shell welds. The finite element model (FEM) is illustrated in Figure 3-2. Geometry and dimensions are taken from design drawings. The applied loadings consist of pressure, thermal and attached piping and support reactions at RV nozzles.

Table 3-1 lists the material properties of SA-508 Class 2 used for the RV shell and nozzle forging base metal. The nozzle-to-shell weld mechanical properties were assumed to be identical to the forging material for the purpose of stress analysis. Table 3-2 lists the material properties for Type 304 stainless steel were used for the cladding.

Figure 3-1: North Anna Units 1 and 2 Reactor Vessel Generic Configuration PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 3-2 Figure 3-2: Overview of FEM PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 3-3 Table 3-1: Base Metal Material Properties (SA-508 Class 2)

Thermal Thermal Heat Capacity, Temp E Temp Conductivity, K Density, Expansion, Diffusivity, Cp

[°F] [x106 psi] [°F] -6 [BTU/(hrft°F)] 2 [lbm/in3]

[x10 in/(in°F)] [ft /hr] [BTU/(lbm°F)]

70 27.9 70 6.07 31.50 0.5692 0.1144 0.28 200 27.7 100 6.13 31.00 0.5509 0.1163 0.28 300 27.4 150 6.25 30.50 0.5421 0.1163 0.28 400 27.0 200 6.38 30.00 0.5246 0.1182 0.28 500 26.4 250 6.49 29.50 0.5075 0.1201 0.28 600 25.7 300 6.60 29.10 0.4928 0.1220 0.28 700 24.8 350 6.71 28.60 0.4770 0.1239 0.28 400 6.82 28.10 0.4616 0.1258 0.28 450 6.92 27.60 0.4467 0.1277 0.28 500 7.02 27.20 0.4338 0.1296 0.28 550 7.12 26.70 0.4198 0.1315 0.28 600 7.23 26.20 0.4061 0.1333 0.28 650 7.33 25.80 0.3915 0.1362 0.28 700 7.41 25.30 0.3763 0.1390 0.28 Table 3-2: Cladding Material Properties (Type 304 Stainless Steel)

Thermal Thermal Heat Capacity, Temp E Temp Conductivity, K Density, Expansion, Diffusivity, Cp

[°F] [x106 psi] [°F] -6 [BTU/(hrft°F)] 2 [lbm/in3]

[x10 in/(in°F)] [ft /hr] [BTU/(lbm°F)]

70 27.4 70 9.11 8.35 0.1498 0.1112 0.29 200 27.1 100 9.16 8.40 0.1495 0.1121 0.29 300 26.8 150 9.25 8.67 0.1525 0.1135 0.29 400 26.4 200 9.34 8.90 0.1548 0.1147 0.29 500 26.0 250 9.41 9.12 0.1568 0.1160 0.29 600 25.4 300 9.47 9.35 0.1589 0.1174 0.29 700 24.9 350 9.53 9.56 0.1601 0.1192 0.29 400 9.59 9.80 0.1630 0.1200 0.29 450 9.65 10.00 0.1639 0.1218 0.29 500 9.70 10.23 0.1659 0.1231 0.29 550 9.76 10.45 0.1684 0.1238 0.29 600 9.82 10.70 0.1707 0.1251 0.29 650 9.87 10.90 0.1721 0.1264 0.29 700 9.93 11.10 0.1736 0.1276 0.29 PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 3-4 3.2 J-INTEGRAL RESISTANCE MODELS North Anna Units 1 and 2 RV are Westinghouse-design vessels whose subject nozzle-to-shell welds were fabricated by Rotterdam Shipyards. The nozzle weld EMA utilizes the B&WOG J-R model 6B reported in BAW-2192, Revision 0, Supplement 1P-A, Revision 0, Appendix A [1]. The justification for the use of Model 6B for North Anna the nozzle-to-shell welds is provided in BAW-2192, Supplement 2P, Revision 0 [2]. For conservatism, the maximum cold leg temperature is utilized. Similarly, the maximum reported copper content and the fluence value at the nozzle-to-shell weld is utilized as summarized in Table 3-3 below. Table 3-4 lists the J-R curve for the nozzle-to-shell welds provided by Framatome.

Table 3-3: J-R Calculation Input Parameters for Nozzle Welds f

Parameter Value Units Comment Cu 0.35 Wt % Maximum for nozzle-to-shell welds Tcold 552 °F Maximum cold leg temperature Clad/Base Metal Fluence, I 1.0 X1018 n/cm2 Maximum for nozzle-to-shell welds Table 3-4: Model 6B J-R curve for Nozzle-to Shell Welds at 552°F for Levels A/B Flaw Extension J-R Lower f a (in.) Bound (lbf/in) 0.005 197 0.010 284 0.020 387 0.040 503 0.050 543 0.075 617 0.100 670 0.125 713 0.150 747 0.175 777 0.200 802 0.250 845 0.300 880 0.350 909 0.400 935 0.450 957 0.500 977 0.550 995 PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 3-5 The J-R curves for the RV nozzle and shell forgings were developed in accordance with NUREG/CR-5729 [3], Table 11, Charpy model without fluence. This Charpy model is the same model described in Section 3.3 of Regulatory Guide 1.161 [6]. The test specimens net-section thickness, Bn of 1.0 inches is used per Section 3 of [6]. The Charpy model is applicable to North Anna nozzle and shell forgings because they are bounded by the range of explanatory variables (fluence, copper content, etc.) used to develop the J-R model. The calculated J-R curve data for the nozzle and shell forging is listed in Table 3-6 and Table 3-7.

The basic form JR is expressed in [3 and 6] as:

JR = (MF)C1(a)C2exp[C3(a)C4] Equation 1

where, MF = margin factors, = 0.749 for Levels A, B and C; MF = 1.0 for Level D a = flaw extension, inches For the Charpy model, C1 is defined in [3, Eq. 10] as:

lnC1 = a1 + a2lnCVN + a3T + a4lnBn Equation 2

where, a1 through a5 are defined in [3, Table 11], and shown in Table 3-5.

CVN = Charpy V-notch Impact Energy, ft-lbs. The 80-year projected USE value is used.

T = temperature, °F Bn = test specimen net thickness, inches. Bn = 1.0 inch is used per Section 3 of [6].

C2 and C3 are defined in [3, Eq. 7 and 8] as:

C2 = d1 + d2lnC1 + d3lnBn Equation 3 C3 = d4 + d5lnC1 + d6lnBn Equation 4

where, d1 through d6 are defined in [3, Table 11], and shown in Table 3-5.

C4 is defined in [3, Table 11], and shown in Table 3-5.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 3-6 Table 3-5: Parameters for RPV Base Metals, Jd Model [3, Table 11]

Parameter Variable Charpy Model a1 (constant) -2.44 a2 ln CVN 1.13 lnC1 a3 T -0.00277 a4 lnBn 0.0801 a5 t d1 (constant) 0.077 C2 d2 lnC1 0.116 d3 lnBn -0.0412 d4 (constant) -0.0812 C3 d5 lnC1 -0.0092 d6 lnBn -0.0295 C4 C4 (exponent) -0.409 Table 3-6: RV Inlet and Outlet Nozzle Forgings J-R Curves a, c, e Flaw Jd for Level A, B, C, MF = 0.749 Jd for Level D, MF = 1 Extension [kip/in] [kip/in]

a [in.] 200°F 300°F 400°F 500°F 600°F 200°F 300°F 400°F 500°F 600°F 0 0 0 0 0 0 0 0 0 0 0 0.001 0.119 0.117 0.116 0.115 0.113 0.159 0.157 0.155 0.153 0.151 0.01 0.54 0.483 0.431 0.386 0.345 0.721 0.644 0.576 0.515 0.46 0.025 0.814 0.703 0.607 0.524 0.452 1.087 0.939 0.81 0.7 0.604 0.05 1.066 0.898 0.756 0.636 0.536 1.424 1.199 1.009 0.85 0.715 0.075 1.233 1.023 0.849 0.705 0.585 1.646 1.366 1.134 0.941 0.781 0.1 1.361 1.118 0.919 0.755 0.62 1.817 1.493 1.226 1.008 0.828 0.2 1.703 1.366 1.096 0.879 0.705 2.273 1.824 1.463 1.174 0.942 0.3 1.928 1.525 1.207 0.955 0.756 2.574 2.036 1.611 1.275 1.009 0.4 2.1 1.645 1.289 1.01 0.792 2.803 2.197 1.721 1.349 1.057 0.5 2.24 1.742 1.355 1.054 0.82 2.991 2.326 1.809 1.407 1.095 0.6 2.361 1.825 1.411 1.09 0.843 3.152 2.436 1.883 1.456 1.125 0.7 2.466 1.897 1.459 1.122 0.863 3.293 2.532 1.947 1.498 1.152 0.8 2.56 1.96 1.501 1.149 0.88 3.418 2.617 2.004 1.534 1.175 0.9 2.646 2.018 1.539 1.174 0.895 3.533 2.694 2.055 1.567 1.195 1 2.724 2.07 1.573 1.196 0.909 3.637 2.764 2.101 1.597 1.213 Note: NUREG/CR-5729 Charpy Model was used.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 3-7 Table 3-7: RV Intermediate Shell Forgings J-R Curves Flaw Jd for Level A, B, C, MF = 0.749 Jd for Level D, MF = 1 a, c, e Extension [kip/in] [kip/in]

a [in.] 200°F 300°F 400°F 500°F 600°F 200°F 300°F 400°F 500°F 600°F 0 0 0 0 0 0 0 0 0 0 0 0.001 0.119 0.117 0.116 0.115 0.113 0.159 0.157 0.155 0.153 0.151 0.01 0.536 0.479 0.428 0.383 0.342 0.716 0.64 0.572 0.511 0.457 0.025 0.807 0.697 0.602 0.519 0.448 1.078 0.93 0.803 0.694 0.599 0.05 1.055 0.889 0.748 0.63 0.53 1.409 1.186 0.999 0.841 0.708 0.075 1.219 1.012 0.84 0.697 0.579 1.628 1.351 1.121 0.931 0.772 0.1 1.345 1.105 0.908 0.746 0.613 1.795 1.475 1.212 0.996 0.818 0.2 1.68 1.348 1.081 0.868 0.696 2.243 1.8 1.444 1.158 0.929 0.3 1.901 1.504 1.19 0.942 0.745 2.538 2.008 1.589 1.257 0.995 0.4 2.069 1.621 1.271 0.996 0.78 2.763 2.165 1.696 1.329 1.042 0.5 2.207 1.717 1.335 1.038 0.808 2.947 2.292 1.782 1.386 1.078 0.6 2.325 1.797 1.389 1.074 0.83 3.104 2.399 1.855 1.434 1.108 0.7 2.428 1.867 1.436 1.104 0.849 3.241 2.493 1.917 1.474 1.134 0.8 2.52 1.929 1.477 1.131 0.866 3.364 2.576 1.972 1.51 1.156 0.9 2.603 1.986 1.514 1.155 0.881 3.476 2.651 2.022 1.542 1.176 1 2.68 2.037 1.548 1.176 0.894 3.578 2.719 2.067 1.571 1.194 Note:

NUREG/CR-5729 Charpy Model was used. The limiting location for the upper shell is near the intermediate shell.

Since the J-R curves for the intermediate shell are more limiting than the upper shell, they are used in the EMA for the upper shell. Additionally, since the upper shell forging stresses were taken from the upper shell to intermediate shell transition, the stress concentration effect was captured, therefore, the upper shell Japplied results are also applicable to the intermediate shell.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-1 4 FRACTURE MECHANICS ANALYSIS The EMA methodology that was used for the North Anna Units 1 and 2 RV locations with projected USE below 50 ft-lbs is consistent with previously NRC approved methodologies for WCAP-13587, Rev. 1, BAW-2178 and BAW-2192. The respective NRC Safety Evaluation Reports are in [12 and 13]. The EMA methodology is discussed further in Section 4.1. Although the Rotterdam nozzle-to-shell welds are projected to have a USE greater than 50 ft-lbs, they are evaluated in this EMA proactively for asset management consideration.

4.1 METHODOLOGY DISCUSSION The Japplied are to be calculated per ASME Section XI, Appendix K [8], which is consistent with BAW-2192, Revision 0, Supplement 1P-A [1]. The maximum Japplied values at the critical time points for service Levels A/B and Levels C/D, along with plots of Japplied vs. flaw depth, will be compared with the J-R curves for the EMA. The Levels A/B service loadings required by ASME Section XI, Appendix K, are an accumulation pressure (internal pressure load) and a cooldown rate (thermal load). For Level A/B, K-1300 and K-4000 of [8] conservatively defined the accumulation pressure as 1.1 times the design pressure, which is a constant pressure of 2750 psia applied throughout the 100°F/hr cooldown transient.

The actual design thermal transients are used for finite element analysis (FEA) stress and input for the K and J calculations, instead of the generic design pressure and cooling rate in Appendix K [8]. As discussed in Section 2.1 of this topical report, the plant cooldown transient is used to bound all Level A/B conditions. This is also consistent with the Appendix K guidance of 100°F/hour cooldown rate. Based on the design specification, there is no Level C transient for North Anna Units 1 and 2, and only the SLB transient is specified for Level D conditions. The Level D thermal and pressure transients are defined in the design specification. Instead of lumping Levels C and D together as traditional EMA would do, this topical report will refer to it as Level D instead of Level C/D for clarity because there is no Level C conditions.

Appendix K of [8] provides various postulated flaw depths, locations, and orientations, as well as the Japplied and stability criteria. Per K-2000 of [8], the postulated flaws shall be oriented along the major axis of the weld of concern. Therefore, only circumferential flaws are applicable to the inlet and outlet nozzle welds. Both axial and circumferential flaws will be postulated for the nozzle and upper shell forgings.

4.1.1 Nozzle-to-Shell Welds and Upper Shell Forging, KI Using A-3200 [8]

For an axial or circumferential flaw of depth a, the SIF due to radial thermal gradients can be calculated per K-4210(c) of [8]. However, since the thermal stresses are based on FEA, the procedure in ASME Section XI, Appendix A [8] is used to calculate the SIFs. This method accurately captures the stress states of the actual geometry. The stress profile representation prescribed in A-3200 of [8] is for a location over the flaw depth (x/a) for which the Ai coefficients need to be recalculated for every flaw depth analyzed. The term x is defined as the distance PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-2 through the wall measured from the flawed surface. In order to simplify the calculation, the analysis herein uses through-wall stress profiles (x/t) in a similar fashion. The procedure in A-3320 of [8] is modified for the use of through-wall stress representation. This x/t approach is consistent with the methods prescribed in publications such as API-579 [10] and the 2015 Edition of ASME Section XI, A-3212 and A-3411(c). Note that the 2015 Edition of ASME Section XI, Appendix A specifies that Gi coefficient tables are applicable for both the x/a and x/t method.

The closed-form solution in K-4210 of [8] for KIp is generic for cylinder geometry, which is appropriate for the RV. However, preliminary results had determined it to be conservative for the nozzle weld locations. Therefore, the method described in A-3200 of [8], including crack face pressure, with an actual FEA pressure stress profile will be used for the SIF calculations.

The through-wall stress profile is represented as follows by a cubic polynomial:



1 4.593 1

6 Where:

a = flaw depth, [in]

t = wall thickness, [in]

l = flaw length, [in]

Ai = coefficients from the cubic polynomial stress profile, i= 0, 1, 2, 3 Ap = 0 for thermal KIt; Ap = internal vessel pressure for pressure KIp y = material yield strength, ASME temperature-dependent value is used, [ksi]

Gi = free surface correction factors from Table A-3320-1 of [8] for point 1, the deepest point PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-3 qy = plastic zone correction factor The plastic zone correction factor, qy, in this application is set to zero because K-4210 of [8] uses the effective flaw depth, ae, which includes ductile flaw extension and a plastic zone correction.

4.1.2 Nozzle Corner KI Closed Form Solution per [11]

The nozzle corner is the bounding location for the nozzle forging. The nozzle corner flaws are considered using the quarter circular crack in a quarter space crack geometry shown in Figure 4-1 for which solutions are available in [11]. Crack tip KI values are computed using:

2 4 0.723 0.551 0.462 0.408 2 3 Where:

= the stress perpendicular to the plane of the crack, and A0, A1, A2, and A3 are the polynomial coefficients for the stress profile x = the distance from the inner surface where the crack initiates a = crack depth Figure 4-1: KI Solution for Quarter Circular Crack in Quarter Space [11, page 5]

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-4 4.1.3 Calculation of Japplied for Small-Scale Yielding The calculation of Japplied due to applied loads accounts for a materials elastic-plastic behavior.

When elastic fracture mechanics with small-scale yielding applies, Japplied may be calculated using crack tip SIF formulae with a plastic zone correction.

The effective flaw depth for small-scale yielding, ae, shall be calculated per K-4210 of [8]:

, [in]

Where, KIp and KIt are SIF due to pressure and thermal stresses, respectively.

Both axial and circumferential KIp and KIt are calculated the same way as KIp and KIt as discussed in Section 4.1.1, except that the flaw depth, a, is substituted with the effective flaw depth, ae. Then, the Japplied for small-scale yielding is calculated using the following formula:

1000 , [in-lb/in2]

Where:

E = E/(1-Q)2 ,[ksi]

E = Youngs modulus, [ksi]

Q = Poissons ratio = 0.3 4.1.4 Postulated Flaw The procedures for the Japplied calculation for Levels C/D described in K-5000 of [8] are the same as those for Levels A/B described in K-4000, except that the effect of cladding/base metal differential thermal expansion needs to be considered for Levels C/D per K-5210(a) of [8]. Therefore, stress data from the finite element model (FEM) with cladding is included for the Levels C/D evaluation.

Additional details of the postulated flaw requirements per K-2200, K-2300 and K-2400 are summarized in Section 2.2.1.

4.1.5 Weld Residual Stress The weld residual stress (WRS) is to be included for Level D to be consistent with the EMA performed in BAW-2192NP, Supplement 1 [13]. The normalized WRS profile is from [9, Section 4.1.3.4, Figure 30]. The WRS was directly added to the nozzle to shell weld FEA thermal stresses for the calculation of KIt.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-5 4.1.6 Stress Due to Mechanical Loads There are a total of four cases of mechanical piping and support load combinations: two cases for Levels A/B and two for Level D. Since the SF is only applicable to pressure, the mechanical stress is directly added to the FEA thermal stress. The maximum through-thickness mechanical stress of the design conditions is added to the corresponding thermal stresses. All KI and Japplied are calculated for all transient time points. The limiting Jappiled at the 0.1 inch flaw extension is reported.

4.1.7 Temperature Range for Upper Shelf Fracture Toughness Evaluations Upper-shelf fracture toughness is determined through use of Charpy V-notch impact energy versus temperature plots by noting the temperature above which the Charpy energy remains on a plateau, maintaining a relatively high constant energy level. Similarly, fracture toughness can be addressed in three different regions on the temperature scale, i.e., a lower-shelf toughness region, a transition region, and an upper-shelf toughness region. Fracture toughness of reactor vessel steel and associated weld metals are conservatively predicted by the ASME initiation toughness curve, KIc, in the lower shelf and transition regions. In the upper shelf region, for the Linde 80 and similar welds (i.e., Rotterdam welds), the upper shelf toughness curve, KJc, is derived from the upper-shelf J-integral resistance model described in Section 3.2. The upper-shelf toughness then becomes a function of fluence, copper content, temperature, and fracture specimen size. When upper-shelf toughness is plotted versus temperature, a plateau-like curve develops that decreases slightly with increasing temperature. Since the present analysis addresses the low upper-shelf fracture toughness issue, only the upper-shelf temperature range, which begins at the intersection of KIc and the upper-shelf toughness curves, is considered.

Transition region toughness is obtained from the ASME Section XI [8] equation for crack initiation, Section A-4200, KIc = 33.2 + 20.734exp[0.02(T-RTNDT)]

Using an RTNDT value of 208.3°F (page 5 of [5]) for a flaw depth of 1/10 the wall thickness where:

KIc = transition region toughness, ksi¥in T = crack tip temperature, °F Stress intensity factors (SIF) are converted to J-integrals by the plane strain relationship,

,where KJc is upper shelf region toughness, in ksi*¥inch, and J0.1 is the J integral resistance at a = 0.1 inch.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-6 4.2 APPLIED J-INTEGRAL RESULTS AND COMPARISON WITH J-R CURVES ALLOWABLES As discussed in Section 2.1, the cooldown transient is evaluated for Levels A/B. FEA through-wall stress profiles were fitted to 3rd order polynomials, and A-3200 of [8] was used for the calculation of KIt and KIp instead of the generic closed-form solution in Appendix K of [8]. As discussed in the methodology Section 4.1, this is more accurate and is an NRC approved method.

Unit pressure (1 ksi) FEA stress profiles were scaled to pressure transients and KIp was then calculated in the same manner as KIt using the 3rd order polynomial method. The crack face pressure was applied as discussed in Section 4.1.1. As discussed in Section 4.1.1, the double counting of the plastic zone correction was removed by setting the qy term in A-3200 of [8] to zero.

The plastic correction was accounted for in the ae term per K-4210 of [8].

4.2.1 Nozzle-to-Shell Welds Level A/B The Japplied values for a 0.1 inch flaw extension with pressure SF = 1.15 and SF =1.25 for Levels A/B are contained in Table 4-1. The Japplied at 0.1-inch flaw extensions (J1) for both inlet and outlet nozzle welds are below the J-R J0.1 = [670 lbf/in at 552°F]f, per Table 3-6. Therefore, the acceptance criteria in ASME Section XI, K-2200 (a)(1) [8] is satisfied. As shown in Figure 4-2 and Figure 4-3, the slope of Japplied is less than the J-R curve at the intersection of both curves (i.e.,

Japplied = J-R). Therefore, the stability acceptance criteria in ASME Section XI, K-2200 (a)(2) [8] is satisfied.

Table 4-1: Inlet and Outlet Nozzle Welds Levels A/B, Circumferential Flaw, Japplied a, c, e, f Inlet Nozzle Weld, at 357°F Outlet Nozzle Weld, at 357°F Flaw Depth Flaw Depth Japplied Flaw Depth Japplied Description (inch) (lbf/in) (inch) (lbf/in) 1/4 T, SF = 1.25 2.471 254.4 2.483 258.2 1/4 T + 0.1 , SF = 1.25 2.571 260.6 2.583 263.9 1/4 T + 0.2 , SF = 1.25 2.671 266.7 2.683 269.6 1/4 T + 0.3 , SF = 1.25 2.771 272.8 2.783 275.3 1/4 T + 0.4 , SF = 1.25 2.871 278.9 2.883 280.9 1/4 T + 0.5 , SF = 1.25 2.971 284.9 2.983 286.6 1/4T + 0.1", SF = 1.15 J1 = 239.8 J1 = 235.0 J0.1 = 670 J0.1 = 670 J-R at 0.1 flaw extension at 552°F at 552°F PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-7 a, c, e, f Figure 4-2: Inlet Nozzle Weld, Circumferential Flaw, Levels A/B Japplied vs. J-R, SF=1.25 PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-8 a, c, e, f Figure 4-3: Outlet Nozzle Weld, Circumferential Flaw, Levels A/B Japplied vs. J-R, SF=1.25 4.2.2 Nozzle-to-Shell Welds Level D As discussed in Section 2.1, there is no applicable Level C transient. The Level D transient is the SLB. Per [2], the B&WOG model 6-B J-R mean curve is used for Level D loading as a best estimate representation of the toughness for the North Anna Unit 1 and 2 Rotterdam welds. The mean J-R curve values for the Rotterdam welds are listed in Table 4-3. Values of KIc and KIc2/E as a function of temperature are contained in Table 4-4. Temperature at which the mean J-R curve intersects KIc2/E is [310°F]f, establishing the start of the upper shelf temperature range.

Figure 4-4 to Figure 4-7 combine the SLB transient Japplied, J-R and KIc2/E curves as follows:

1. The B&WOG Model 6-B mean J-R curve is used.
2. Figure 4-4 and Figure 4-6 present Japplied curves due to the Level D SLB transient, the mean J-R curve and KIc2/E curves as a function of crack tip temperature. The Japplied curve is truncated at temperature point of [310°F]f (limiting or lowest temperature for upper shelf toughness. Figure 4-4 illustrates the inlet nozzle location case. Figure 4-6 illustrates the outlet nozzle location case. All points of the transient remain below the mean J-R curve.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-9

3. Figure 4-5 and Figure 4-7 show the Japplied and the mean J-R curve [(calculated for 310°F and a constant fluence of 1E18 n/cm2)]f as a function of crack extension. Figure 4-5 presents the inlet nozzle Japplied at temperature of the crack tip temperature of [275°F]a, c, e.

Figure 4-7 shows the outlet nozzle Japplied at the crack tip temperature of [291°F]a, c, e.

These temperatures are conservative since Japplied is lower at the lowest upper shelf temperature. The slope of the Japplied is less than the slope of the mean J-R curve at the point of intersection, which demonstrates that the flaw is stable as required by ASME Section XI, Appendix K, K-3400.

The Japplied values at a 0.1 inch flaw extension with SF = 1 for Level D are contained in Table 4-2. Since the 1/10 of the wall thickness plus cladding exceeded 1 inch for all evaluated locations, the postulated flaw depth is 1 inch. As shown in Table 4-2, all applied J1 for the nozzle-to-shell welds are below the J0.1 of [1,223 lb/in at 310°F]f. The acceptance criteria in ASME Section XI, K-2400 (a) [8] is satisfied.

Table 4-2: Inlet and Outlet Nozzle Welds Level D, Circumferential Flaw, Limiting Japplied a, c, e, f Inlet Nozzle Weld, at 275°F Outlet Nozzle Weld, at 291°F Flaw Depth Flaw Depth Japplied Flaw Depth Japplied Description (inch) (lbf/in) (inch) (lbf/in) 1/10 T 1.0 677.4 1.0 984.5 1/10 T + 0.1 1.1 713.2 1.1 1,004.0 1/10 T + 0.2 1.2 745.8 1.2 1,018.5 1/10 T + 0.3 1.3 775.6 1.3 1,029.0 1/10 T + 0.4 1.4 802.8 1.4 1,036.1 1/10 T + 0.5 1.5 827.7 1.5 1,040.5 1/10 T + 0.1", SF = 1.0 J1 = 713.2 J1 = 1,004.0 J-R at 0.1 flaw extension, J0.1 = 1,223 J0.1 = 1,223 interpolated at 310°F per Table 4-3 PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-10 Table 4-3: B&WOG Model 6-B Mean J-R Curve with a = 0.1 inch f

Fluence = 1.0 x1018 n/cm2 (no attenuation) a = 0.1 inch Cu = 0.35 wt%

BN = 0.8 inch T (°F) lnC1 C1 C2 C3 Mean J0.1 (lb/in) 200 1.30 3.67 0.14 -0.38 1,367 250 1.27 3.56 0.12 -0.41 1,299 300 1.24 3.46 0.10 -0.45 1,235 350 1.21 3.35 0.09 -0.49 1,174 400 1.18 3.25 0.07 -0.52 1,116 450 1.15 3.16 0.05 -0.56 1,061 500 1.12 3.06 0.03 -0.59 1,008 550 1.09 2.97 0.01 -0.63 958 600 1.06 2.88 -0.01 -0.67 911 Table 4-4: KIc2/E Curve a, c, e, f T (°F) T-RTNDT (°F) KIc(ksi¥in) E (ksi) KIc2/E (lb/in) 200 -8 51 30,440 85 220 12 59 30,374 116 240 32 72 30,308 172 260 52 92 30,242 277 280 72 120 30,176 479 300 92 163 30,110 882 320 112 227 30,022 1,713 340 132 322 29,934 3,464 360 152 464 29,846 7,215 PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-11 a, c, e, f UpperShelfTemperatureRange

Figure 4-4: Inlet Nozzle-to-Shell Weld, J-integral vs. Temperature PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-12 1800 a, c, e, f 1600 1400 1200 1000 J(lb/in) 800 600 400 JRMean 200 SLB 0

0 0.1 0.2 0.3 0.4 0.5 a(in)

Figure 4-5: Inlet Nozzle-to-Shell Weld, J-integral vs. Flaw Extension PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-13 a, c, e, f UpperShelfTemperatureRange

Figure 4-6: Outlet Nozzle-to-Shell Weld, J-integral vs. Temperature PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-14 1800 a, c, e, f 1600 1400 1200 1000 J(lb/in) 800 600 400 JRMean 200 SLB 0

0 0.1 0.2 0.3 0.4 0.5 a(in)

Figure 4-7: Outlet Nozzle-to-Shell Weld, J-integral vs. Flaw Extension Additionally, as discussed in Section (a), K-5300(b) also requires that the remaining ligament is not subject to tensile instability. Table 4-5 contains the necessary inputs and a sample calculation for tensile instability pressure using a flaw depth a=1.181 inch. Additionally, a range of flaw depths from 0.098 to 1.968 inches were calculated to be in excess of 10 ksi, which is significantly greater than the 2.5 ksi pressure expected during a SLB transient.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-15 Table 4-5: K-5300 Tensile Instability Check for RV Nozzle-to-Shell Weld 0 = y (ksi, at 300°F) 45.25 a, c, e, f Ri (in) 77.91 Rm (in) 82.83 t (in, nozzle belt wall thickness per) 9.84 l (in, aspect ratio of 6:1) 6a = 7.085 a (in) 1.181 A (in )

2 166.540 Ac (in )2 6.570 PI (ksi) 12.359 4.2.3 Upper Shell Forging Level A/B The Japplied values for a 0.1 inch flaw extension with pressure SF = 1.15 and SF =1.25 for Level A/B are contained in Table 4-6. The J-R J0.1 values from Table 3-7 are interpolated to the respective actual crack tip temperatures of [350°F and 460°F]a, c, e in Table 4-6 to instead of using a conservative J0.1 from a higher temperature. Both the circumferential and axial flaw applied J1 are below the J0.1 at their respective temperatures. Therefore, the acceptance criteria in ASME Section XI, K-2200 (a)(1) [8] is satisfied. As shown in Figure 4-8 and Figure 4-9, the slope of Japplied is less than the J-R curve at the intersection of both curves (i.e., Japplied = J-R). Therefore, the stability acceptance criteria in ASME Section XI, K-2200 (a)(2) [8] is satisfied. Since the upper shell forging FEA stresses were taken from the thicker upper shell to the thinner intermediate shell region, it captured the stress concentration effect, therefore, the upper shell forging results are also applicable to the intermediate shell forgings.

Table 4-6: Upper Shell Forging Level A/B, Circumferential Flaw, Limiting Japplied Circumferential Flaw Axial Flaw a, c, e at 350°F at 460°F Flaw Flaw Depth Flaw Depth Japplied Depth Japplied Description (inch) (lbf/in) (inch) (lbf/in) 1/4 T, SF = 1.25 1.938 295.7 1.938 691.7 1/4 T + 0.1 , SF = 1.25 2.038 307.9 2.038 731.5 1/4 T + 0.2 , SF = 1.25 2.138 320.3 2.138 772.3 1/4 T + 0.3 , SF = 1.25 2.238 332.9 2.238 814.3 1/4 T + 0.4 , SF = 1.25 2.338 345.7 2.338 857.5 1/4 T + 0.5 , SF = 1.25 2.438 358.8 2.438 901.8 1/4T + 0.1", SF = 1.15 J1 = 271.3 J1 = 615.6 J0.1 = 1007 J0.1 = 811 Interpolated J-R at 0.1 flaw extension at 350°F at 460°F PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-16 a, c, e Figure 4-8: RV Upper Shell, Circumferential Flaw, Level A/B Japplied vs. J-R, SF=1.25 PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-17 a, c, e Figure 4-9: RV Upper Shell, Axial Flaw, Level A/B Japplied vs. J-R, SF=1.25 4.2.4 Upper Shell Forging Level D The upper shell forging Japplied values for a 0.1 inch flaw extension with SF = 1 Level D are contained in Table 4-7. The J-R J0.1 at 600°F from Table 3-7 are used for conservatism. Both the circumferential and axial flaw applied J1 are below the J0.1. Therefore, the acceptance criteria in ASME Section XI, K-2400 (a) [8] is satisfied. As shown in Figure 4-10 and Figure 4-11, the slope of Japplied is less than the J-R curve at the intersection of both curves (i.e., Japplied = J-R). Therefore, the stability acceptance criteria in ASME Section XI, K-3400 [8] is satisfied. As shown in Table 4-8, the Level D, SLB transient internal pressure of 2.5 ksi is significantly less than the tensile instability pressures calculated per K-5300; therefore, the remaining ligament is not subjected to tensile instability. Since the upper shell forging FEA stresses were taken from the thicker upper shell to the thinner intermediate shell region, it captured the stress concentration effect, therefore, the upper shell forging results are also applicable to the intermediate shell forgings.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-18 Table 4-7: Upper Shell Forging Level D, Limiting Japplied Circumferential Flaw Axial Flaw a, c, e at 345°F at 345°F Flaw Depth Flaw Depth Japplied Flaw Depth Japplied Description (inch) (lbf/in) (inch) (lbf/in) 1/10 T 0.934 606.1 0.934 629.2 1/10 T + 0.1 1.034 630.8 1.034 662.6 1/10 T + 0.2 1.134 652.4 1.134 693.1 1/10 T + 0.3 1.234 671.3 1.234 721.2 1/10 T + 0.4 1.334 688.0 1.334 747.2 1/10 T + 0.5 1.434 702.7 1.434 771.4 1/10 T + 0.1", SF = 1.0 J1 = 630.8 J1 = 662.6 J0.1 = 818 J0.1 = 818 J-R at 0.1 flaw extension at 600°F at 600°F a, c, e Figure 4-10: RV Upper Shell, Circumferential Flaw, Level D Japplied vs. J-R PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-19 a, c, e Figure 4-11: RV Upper Shell, Axial Flaw, Level D Japplied vs. J-R Table 4-8: K-5300 Tensile Instability Check for RV Upper Shell a, c, e Circumferential Flaw Axial Flaw 0 (ksi, at 600°F) 61.05 61.05 Ri (in) 78.66 78.66 Rm (in) 82.5 N/A t (in, FEA cutline length) 7.909 7.909 l (in) 6a, for l:a = 6 a = 1/10 t + 0.1 (in) 1.034 1.034 A (in )2 111.62 111.62 Ac (in )2 5.04 5.04 PI (ksi) 6.57 6.24 PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-20 4.2.5 Nozzle Forging Level A/B The nozzle corner is the limiting location for the nozzle forging due to the wall thickness and the stress concentration effect. The Japplied values for a 0.1 inch flaw extension with pressure SF =

1.15 and SF =1.25 for Level A/B are contained in Table 4-9. All the applied J1 values are less than the respective J0.1 from Table 3-6. Therefore, the acceptance criteria in ASME Section XI, K-2200 (a)(1) [8] is satisfied. As shown in Figure 4-12 to Figure 4-15, the slope of Japplied is less than the J-R curve at the intersection of both curves (i.e., Japplied = J-R). Therefore, the stability acceptance criteria in ASME Section XI, K-2200 (a)(2) [8] is satisfied.

Table 4-9: Nozzle Corner Level A/B, Limiting Japplied Circumferential Flaw Axial Flaw a, c, e Inlet Nozzle Outlet Nozzle Inlet Nozzle Outlet Nozzle Corner at 355°F Corner at 547°F Corner at 340°F Corner at 354°F Flaw Flaw Flaw Flaw Flaw Depth Depth Japplied Depth Japplied Depth Japplied Depth Japplied Description (inch) (lbf/in) (inch) (lbf/in) (inch) (lbf/in) (inch) (lbf/in) 1/4 T, SF = 1.25 2.56 4.63 3.73 3.61 2.50 106.86 4.04 776.16 1/4 T + 0.1 , SF = 1.25 2.66 4.71 3.83 3.65 2.60 109.83 4.14 788.84 1/4 T + 0.2 , SF = 1.25 2.76 4.77 3.93 3.68 2.70 112.74 4.24 801.28 1/4 T + 0.3 , SF = 1.25 2.86 4.84 4.03 3.71 2.80 115.59 4.34 813.48 1/4 T + 0.4 , SF = 1.25 2.96 4.91 4.13 3.73 2.90 118.38 4.44 825.44 1/4 T + 0.5 , SF = 1.25 3.06 4.98 4.23 3.76 3.00 121.11 4.54 837.16 1/4T + 0.1", SF = 1.15 J1 = 5.1 J1 = 3.0 J1 = 99.8 J1 = 677.0 J0.1 = J0.1 =

J-R at 0.1 flaw extension, J0.1 = 919 J0.1 = 919 620 620 per Table 3-6 at 400°F at 400°F at 600°F at 600°F PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-21 a, c, e Figure 4-12: Inlet Nozzle Corner, Circumferential Flaw, Level A/B Japplied vs. J-R, SF=1.25 PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-22 a, c, e Figure 4-13: Outlet Nozzle Corner, Circumferential Flaw, Level A/B Japplied vs. J-R, SF=1.25 PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-23 a, c, e Figure 4-14: Inlet Nozzle Corner, Axial Flaw, Level A/B Japplied vs. J-R, SF=1.25 PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-24 a, c, e Figure 4-15: Outlet Nozzle Corner, Axial Flaw, Level A/B Japplied vs. J-R, SF=1.25 4.2.6 Nozzle Forging Level D The Japplied values for a 0.1 inch flaw extension for Level D are contained in Table 4-10. All the applied J1 for the nozzle forgings are less than the J0.1 of [828 lbf/in at 600°F]a, c, e from Table 3-6.

Therefore, the acceptance criteria in ASME Section XI, K-2400 (a) [8] is satisfied. As shown in Figure 4-16 to Figure 4-19, the slope of Japplied is less than the J-R curve at the intersection of both curves (i.e., Japplied = J-R). Therefore, the stability acceptance criteria in ASME Section XI, K-3400

[8] is satisfied. As shown in Table 4-11, the Level D internal pressure of 2.5 ksi is significantly less than the tensile instability pressures calculated per K-5300, therefore, the remaining ligament is not subjected to tensile instability.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-25 Table 4-10: Nozzle Corner Level D, Limiting Japplied a, c, e Circumferential Flaw Axial Flaw Inlet Nozzle Outlet Nozzle Inlet Nozzle Outlet Nozzle Corner at 373°F Corner at 547°F Corner at 346°F Corner at 329°F Flaw Flaw Flaw Flaw Flaw Depth Depth Japplied Depth Japplied Depth Japplied Depth Japplied Description (inch) (lbf/in) (inch) (lbf/in) (inch) (lbf/in) (inch) (lbf/in) 1 1.0 124.1 1.0 12.84 1.0 274.5 1.0 329.7 1 + 0.1 1.1 129.2 1.1 13.39 1.1 289.1 1.1 355.7 1 + 0.2 1.2 133.5 1.2 13.84 1.2 302.0 1.2 380.6 1 + 0.3 1.3 137.0 1.3 14.21 1.3 313.5 1.3 404.5 1 + 0.4 1.4 139.8 1.4 14.49 1.4 323.6 1.4 427.3 1 + 0.5 1.5 141.9 1.5 14.69 1.5 332.4 1.5 449.1 1/10 T + 0.1", SF = 1.0 J1 = 129.2 J1 = 13.39 J1 = 289.1 J1 = 355.7 J-R at 0.1 flaw extension, J0.1 = 828 J0.1 = 828 J0.1 = 828 J0.1 = 828 per Table 3-6 at 600°F at 600°F at 600°F at 600°F PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-26 a, c, e Figure 4-16: Inlet Nozzle Corner, Circumferential Flaw, Level D Japplied vs. J-R, SF=1.0 PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-27 a, c, e Figure 4-17: Outlet Nozzle Corner, Circumferential Flaw, Level D Japplied vs. J-R, SF=1.0 PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-28 a, c, e Figure 4-18: Inlet Nozzle Corner, Axial Flaw, Level D Japplied vs. J-R, SF=1.0 PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 4-29 a, c, e Figure 4-19: Outlet Nozzle Corner, Axial Flaw, Level D Japplied vs. J-R, SF=1.0 Table 4-11: K-5300 Tensile Instability Check for RV Nozzle Corner Circumferential Flaw Axial Flaw a, c, e Inlet Nozzle Outlet Nozzle Inlet Nozzle Outlet Nozzle 0 (ksi, at 600°F) 61.05 61.05 61.05 61.05 Ri (in) 77.91 77.91 77.91 77.91 Rm (in) 82.83 82.83 N/A N/A t (in, FEA cutline length) 10.403 16.347 10.173 16.347 l (in) circular crack l = a = 1.1 a = 1/10 t + 0.1 (in) 1.1 1.1 1.1 1.1 A (in )2 119.67 285.21 114.68 285.21 Ac (in2) 0.95 0.95 0.95 0.95 PI (ksi) 8.72 13.71 8.45 13.65 PWROG-19047-NP May 2020 Revision 0

WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 5-1 5 CONCLUSIONS The North Anna Units 1 and 2 RV nozzle-to-shell welds, nozzle forgings and upper shell forgings were evaluated for equivalent margins of safety per ASME Code Section XI [8]. The flaw extension and stability criteria of ASME Section XI, Appendix K are satisfied.

Levels A/B For all evaluated locations, the Japplied at 0.1-inch flaw extension with a structural factor (SF) of 1.15 for pressure and SF of 1.0 for thermal are less than the J-material at the 0.1-inch flaw extension. Therefore, the acceptance criteria in ASME Section XI, K-2200 (a)(1) [8] is satisfied.

The slope of Japplied (SF=1.25) is less than the J-material (J-R curve) at the intersection of both curves (i.e., Japplied = J-R). Therefore, the stability acceptance criteria in ASME Section XI, K-2200 (a)(2) [8] is satisfied.

Level D For all evaluated locations, the Japplied at 0.1-inch flaw extension with a SF of 1.0 are less than the J-R at the 0.1-inch flaw extension. Therefore, the acceptance criteria in ASME Section XI, K-2400 (a) [8] is satisfied. The slope of Japplied is less than the J-R curve at the intersection of both curves (i.e., Japplied = J-R). Therefore, the stability acceptance criteria in ASME Section XI, K-3400 [8] is satisfied. All flaws evaluated for Level D assumed 1/10 of the wall thickness (including cladding and limited to 1 inch) plus a 0.1 inch flaw extension. The results demonstrate that flaw growth is stable at less than 75% of the wall thickness since the applied J-integral intersects the mean J-integral resistant curve at a small fraction of the thickness. This satisfies the 75% of wall thickness requirement per K-2400 (c). Additionally, the maximum Level D internal pressure is less than the tensile instability pressures calculated per K-5300 (b) for all evaluated locations and flaws.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 6-1 6 REFERENCES

1. BAW-2192, Revision 0, Supplement 1P-A, Revision 0, Low Upper-Shelf Toughness Fracture Mechanics Analysis of Reactor Vessels of B&W Owners Reactor Vessel Working Group for Levels A & B Service Loads, December, 2018.
2. BAW-2192, Revision 0, Supplement 2P, Revision 0, Low Upper-Shelf Toughness Fracture Mechanics Analysis of Reactor Vessels of B&W Owners Reactor Vessel Working Group for Levels A & B Service Loads.
3. NUREG/CR-5729, Multivariable Modeling of Pressure Vessel and Piping J-R Data, May 1991.
4. Code of Federal Regulations, 10 CFR Part 50, Appendix G, Fracture Toughness Requirements, U.S. Nuclear Regulatory Commission, Washington D.C., Federal Register, Volume 77, No. 14, January 23, 2012.
5. North Anna Power Station Updated Final Safety Analysis Report, Revision 55.
6. Regulatory Guide 1.161, Evaluation of Reactor Pressure Vessels with Charpy Upper-Shelf Energy Less than 50 ft-lb, U.S. Nuclear Regulatory Commission, June 1995.
7. ASME Boiler and Pressure Vessel Code,Section III, 1968 Edition, with Addenda up to and including Winter 1968.
8. ASME Boiler and Pressure Vessel Code,Section XI, 2013 Edition.
9. Fracture Analysis of Vessels - Oak Ridge FAVOR, v05.1, Computer Code: Theory and Implementation of Algorithms, Methods, and Correlations, ORNL/NRC/LTR-05/18 (ADAMS Accession Number ML063350323).
10. API 579-1/ASME FFS-1, Fitness-For-Service, Annex C, Compendium of Stress Intensity Factor Solutions, June, 2016.
11. S. A. Delvin and P. C. Riccardella, Fracture Mechanics Analysis of JAERI Model Pressure Vessel Test, ASME Paper No. 78-PVP-91, Proceedings of the 1978 ASME Pressure Vessels and Piping Conference, June 25-30, 1978, Montreal, Quebec, Canada.
12. NRC SE Report, Safety Assessment of Report WCAP-13587, Revision 1, Reactor Vessel Upper Shelf Energy Bounding Evaluation For Westinghouse Pressurized Water Reactors, September 1993, April 21, 1994.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 FRAMATOME INC. NON-PROPRIETARY 6-2

13. NRC SE Report, Final Safety Evaluations for BAW-2192, Supplement 1NP, Revision, Low Upper-Shelf Toughness Fracture Mechanics Analysis of Reactor Vessels of B&W Owners Reactor Vessel Working Group for Level A&B Service Loads and BAW-2178, Supplement 1NP, Revision 0, Low Upper-Shelf Toughness Fracture Mechanics Analysis of Reactor Vessels of B&W Owners Reactor Vessel Working Group for Level C&D Service Loads, ML19106A196, April 29, 2019.

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