ML18170A114

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PWROG-17033-NP, Revision 1, Update for Subsequent License Renewal: WCAP-13045, Compliance to ASME Code Case N-481 of the Primary Loop Pump Casings of Westinghouse Type Nuclear Steam Supply Systems.
ML18170A114
Person / Time
Site: 99902037
Issue date: 06/14/2018
From: Loy G
PWR Owners Group, Westinghouse
To:
Office of Nuclear Reactor Regulation
References
OG-18-142, PA-MSC-1498, Rev. 0, WCAP-13045 PWROG-17033-NP, Rev. 1
Download: ML18170A114 (24)
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PRESSURIZ D WATER REACTOR OWNERS GROUP PWROG-17033-NP Revision 1 WESTINGHOUSE NON-PROPRIETARY CLASS 3 Update for Subsequent License Renewal: WCAP-13045, "Compliance to ASME Code Case N-481 of the Primary Loop Pump Casings of Westinghouse Type Nuclear Steam Supply Systems" Materials Committee PA-MSC-1498, Revision 0 June 2018 @Westinghouse WESTINGHOUSE NON-PROPRIETARY CLASS 3 PWROG-17033-NP Revision 1 Update for Subsequent License Renewal: WCAP-13045, "Compliance to ASME Code Case N-481 of the Primary Loop Pump Casings of Westinghouse Type Nuclear Steam Supply Systems" PA-MSC-1498, Revision 0 June 2018 Authors: Geoffrey Loy* Structural Design and Analysis Ill Reviewer: Anees Udyawar

  • Structural Design and Analysis Ill Approved:

Lynn Patterson*, Manager Structural Design and Analysis 111 James Molkenthin*, Program Director PWR Owners Group PMO *Electron i cally approved records are authenticated in the electronic document management system. Westinghouse Electric Company LLC 1000 Westinghouse Drive Cranberry Township , PA 16066 , USA © 2018 Westinghouse Electric Company LLC All Rights Reserved * * * * * * * * * * * * * * * * * * * * * * * * * : 1 * * * * * * * * * * * * * * * *

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  • WESTINGHOUSE NON-PROPRIETARY CLASS 3 iii ACKNOWLEDGEMENTS This report was developed and funded by the PWR Owners Group under the leadership of the participating utility representatives of the Materials Committee . PWROG-17033-NP June 2018 Revision 1 WESTINGHOUSE NON-PROPRIETARY CLASS 3 iv LEGAL NOTICE This report was prepared as an account of work performed by Westinghouse Electric Company LLC. Neither Westinghouse Electric Company LLC, nor any person acting on its behalf: 1. 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 2. 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 affiliates, subcontractors and/or 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. Any unauthorized use of this document is prohibited.

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 party's 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.

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-17033-NP June 2018 Revision 1 * * * * * * * * * * * * * * * ** * * * * * * * * * * * * * * * * * * * * * * * * * * *

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  • WESTINGHOUSE NON-PROPRIETARY CLASS 3 v PWR Owners Group United States Member Participation*

for PA-MSC-1498, Revision O [4] 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 Units 1 , 2 , & 3 (CE) X Millstone 2 (CE) X Dominion Connecticut Millstone 3 (W) X North Anna 1 & 2 (W) X Dominion VA Surry 1 & 2 (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 TMI 1 (B&W) X Calvert Cliffs 1 & 2 (CE) X Ginna (W) X Beaver Valley 1 & 2 (W) X FirstEnergy Nuclear Operating Co. X Davis-Besse (B&W) St. Lucie 1 & 2 (CE) X Turkey Point 3 & 4 (W) X Florida Power & Light\ NextEra X Seabrook (W) Pt. Beach 1 & 2 (W) X Luminant Power Comanche Peak 1 & 2 (W) X PWROG-17033-NP June 2018 Revision 1 WESTINGHOUSE NON-PROPRIETARY CLASS 3 PWR Owners Group United States Member Participation*

for PA-MSC-1498, Revision O [4] Participant Utility Member Plant Site(s) Yes No Omaha Public Power District Fort Calhoun (CE) X Pacific Gas & Electric Diablo Canyon 1 & 2 (W) X PSEG -Nuclear Salem 1 & 2 (W) X South Carolina Electric & Gas V.C. Summer (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. vi PWROG-17033-N P June 2018 Revision 1 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *I * * * * * *

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  • WESTINGHOUSE NON-PROPRIETARY CLASS 3 PWR Owners Group International Member Participation*

for PA-MSC-1498, Revision 0 Participant Utility Member Plant Site(s) Yes Asco 1 & 2 (W) Asociaci6n Nuclear Asc6-Vandell6s Vandellos 2 (W) AxpoAG Beznau 1 & 2 (W) Centrales Nucleares Almaraz-Trillo Almaraz 1 & 2 (W) EDF Energy Sizewell B (W) Doel 1 , 2 & 4 (W) Electrabel Tihange 1 & 3 (W) Electricite de France 58 Units Elektriciteits Produktiemaatschappij Zu i d-Borssele 1 (Siemens)

Nederland Eletronuclear -Eletrobras Angra 1 (W) Emirates Nuclear Energy Corporation Barakah 1 & 2 Eskom Koeberg 1 & 2 (W) Hokkaido Tomari 1, 2 & 3 (MHI) Japan Atomic Power Company Tsuruga 2 (MHI) Mihama 3 (W) Kansai Electric Co., LTD Ohi 1 , 2, 3 & 4 (W & MHI) Takahama 1, 2 , 3 & 4 (W & MHI) Kori 1, 2, 3 & 4 (W) Hanbit 1 & 2 (W) Korea Hydro & Nuclear Power Corp. Hanbit 3 , 4, 5 & 6 (CE) Hanul 3 , 4 , 5 & 6 (CE) Genkai 2 , 3 & 4 (MHI) Kyushu Sendai 1 & 2 (MHI) Nuklearna Electrarna KRSKO Krsko (W) Ringhals AB Ringhals 2 , 3 & 4 (W) Shikoku lkata 1, 2 & 3 (MHI) Taiwan Power Co. Maanshan 1 & 2 (W)

  • 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 . No X X X X X X X X X X X X X X X X X X X X X X X X X X X vii PWROG-17033-NP June 2018 Revision 1 WESTINGHOUSE NON-PROPRIETARY CLASS 3 viii TABLE OF CONTENTS 1 PURPOSE ...........................................

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1-1 2 BACKGROUND

............................................................................................................. 2-1 2.1 OPERATING EXPERIENCE AND APPLICATION OF LATEST FRACTURE TOUGHNESS DATABASE ..............................................

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2-2 3 STABILITY ANALYSIS AND FRACTURE TOUGHNESS

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3-1 3.1 FRACTURE TOUGHNESS DETERMINED IN WCAP-13045

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3-1 3.2 FRACTURE TOUGHNESS BASED ON NUREG/CR-4513, REVISION 2 ......... 3-3 4 FATIGUE CRACK GROWTH ANALYSIS ....................................................................... 4-1 5 CONCLUSIONS

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................... 5-1 6 REFERENCES

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................................................ 6-1 APPENDIX A : ASME CODE SECTION XI CODE CASE N-481 .....................................

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  • WESTINGHOUSE NON-PROPRIETARY CLASS 3 1-1 1 PURPOSE The purpose of this Topical Report (TR) is to extend the fracture mechanics integrity evaluation in WCAP-13045

[1], "Compliance to ASME Code Case N-481 of the Primary Loop Pump Casings of Westinghouse Type Nuclear Steam Supply Systems ," through Subsequent License Renewal (SLR), 80 years of operation. In the past , plants have used the generic fracture mechanics evaluation performed in WCAP-13045 to comply with the requirements of ASME Code Case N-481 for plant-specific license renewal applications to extend plant operations to 60 years. In this TR , the fracture mechanics evaluation provides the justification for performing visual inspections , in lieu of volumetric inspections , for reactor coolant pump (RCP) casings as incorporated in the ASME Code Section XI , and extend the applicability of WCAP-13045 to 80 years of operation for all plants with Westinghouse pump casings . ASME Section XI Table IWB-2500-1 , Examination Categories

[2) required performing periodic volumetric inspections of the welds of the primary loop pump casings in nuclear power plants. Since these inspections result in radiation exposure to the personnel performing the inspections and require sign i ficant resources to perform the inspections , the ASME Code Committee approved Code Case N-481 [3) in March 1990 (see Appendix A of this report) that allows an alternative to the volumetric inspection requirement.

The NRC endorsed Code Case N-481 in Regulatory Guide 1.147 , "lnservice Inspection Code Case Acceptability ASME Code Section XI Division 1 ," in April 1992 . Westinghouse design primary loop pump casings are heavy-wall cast stainless steel. A volumetric i nspection of the full thickness of the welds using the ultrasonic test method from the outside diameter surface is impractical due to the severe attenuation associated with the large grain structures. A volumetric inspection of the full thickness of the welds would require unconventional approaches (inside diameter and outside diameter ultrasonic testing or radiographic testing) that require access to the internal side of the pump casing . ASME Code Case N-481 [3) allowed replacing the volumetric examination of primary loop pump casings with a fracture mechanics-based integrity evaluation supplemented by specific visual inspections. WCAP-13045

[1) contains the integrity evaluation that was performed to demonstrate compliance with ASME Code Case N-481 for 40 years of operation . Since WCAP-13045

[1) was issued in September 1991 , the ASME Code tables have been updated over time to be consistent with the guidance in Code Case N-481 to require visual inspections of the primary loop pump casings. In March 2004, Code Case N-481 was annulled by ASME , and the information in Code Case N-481 was implemented into the 2008 Addenda of ASME Code Section XI. Note that the ASME Section XI 2000 Addenda replaced the pump casing weld B-L-1 volumetric examinations with visual examinations , while the ASME Section XI 2008 Addenda eliminated the pump casing weld (B-L-1) examinations completely. The only required examination is a visual examination of the pump casing (B-L-2) when the pump is disassembled for ma i ntenance or repair . The technical basis for WCAP-13045 was based on experience with evaluations performed for an assumed 40 year life. Due to the SLR program to extend an operating license to 80 years , PWROG-17033-N P June 2018 Revision 1 WESTINGHOUSE NON-PROPRIETARY CLASS 3 1-2 the integrity evaluations in WCAP-13045 were reviewed and confirmed to be app l icable fo r 80 years of service. The fracture mechanics integrity evaluat i on in this report , as well as the requirements in Code Case N-481 (now incorporated into the ASME Code Section XI) were reviewed to confirm that the visual inspections for pump casings continue to remain valid for an 80 year life. WCAP-13045

[1] contains the fracture mechanics based integrity evaluation for cast austenitic stainless steel pump casings as required by Code Case N-481 [3]. The evaluations contained in WCAP-13045 are applicable to Westinghouse design RCPs. There are eight different models of pumps: Models 63 , 70 , 93 , 93A , 93A-1 , 930 , 1 OOA , and 1000. Models 63 , 70 , 93 and 930 , which have a tangent outlet nozzle. Models 93A and 93A-1 have outlet nozzles that are rad i ally orientated.

Models 1 OOA and 1000 are similar to the general design of the Model 93 , except for a radially oriented outlet nozzle that is consistent with the Model 93A. Models 93 , 93A and 93A-1 are the most commonly used RCPs in Westinghouse Nuclea r Steam Supply System (NSSS) plants. WCAP-13045 contains a model that is representative of each of the outlet nozzle configurations that was used for a 30 finite element s t ress analysis and fracture evaluation (the inlet n o zzles are reasonably axisymmetric with the pump casing proper). The representat i ve models chosen were the Model 93A (radial outlet nozz l e) and Model 93 (tangent i al outlet nozzle). The material of the pump casings is fabricated from SA-351 CF8 , except for the pumps of three plants which were fabricated from SA-351 CF8M. The SA-351 CF8 and CF8M are known to be susceptible to thermal aging. WCAP-13045 addressed thermal aging of the cast austenitic stainless steel pump casings (CF8 and CF8M) by using end of life (40 years) fracture toughness values for all Westinghouse design pump casings. The fracture toughness criteria were established using the lowest toughness for each pump component.

This report justifies the continued use of the end of life frac t ure toughness values determined in WCAP-13045 for 80 years of service. The fracture toughness is used in WCAP-13045 as part of the elastic plastic f~acture mechanics (EPFM) analysis based on the J-integral approach; therefore , it is necessary to confirm the fracture toughness values for an 80 year evaluation , and demonstrate that the EPFM ana l ysis continues to remain valid for 80 years. The J-integral evaluation also used bound i ng loads that covered a wide range of pump casing nozzle loads from the various different plants. Th i s report only confirms the toughness properties for 80 years , and not the applied loads , since the applied load i ngs in the J-integral analysis cons i dered in WCAP-13045 will not be i mpacted by li cense extension to 80 years of operation because they are not time dependent.

Note that the f r acture toughness properties based on the CF8M (high molybdenum content) material is more susceptible (limiting) to thermal aging than the CF8 material.

Therefore , the CF8M material is used in the fracture mechanics evaluation in this TR; and the conclusions for the CF8M fracture toughness determined in this report also apply to the CF8 mater i a l. Fatigue crack growth evaluations were also determined in WCAP-13045 for the high stress outlet nozzle crotch regions. Various crack sizes were considered in the evaluat i ons , and based on the evaluations , it was demonstrated that the fatigue crack growth was small. The PWROG-17033

-NP J un e 2018 Re vi s i on 1 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

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  • WESTINGHOUSE NON-PROPRIETARY CLASS 3 1-3 discussion in this report also justifies that the fatigue crack growth evaluations contained in WCAP-13045 are still applicable for the 80 year design life . The following two items were reviewed to confirm the applicability of WCAP-13045

[1] for 80 years of service: 1. Confirm that the fracture toughness (J 1 c -J at crack initiation and Jma x -J at maximum crack extension) used in WCAP-13045

[1] and the associated tearing modulus (T ma t) for the stability analysis are applicable for 80 years of service. The postulated 1/4T flaw size used in the stability analysis is compared to the final flaw size due to fatigue crack growth . 2. Confirm that the generic fatigue crack growth (FCG) analysis performed in WCAP-13045 is applicable for 80 years of service , specifically

the stresses , stress intensity factor (SIF) equations, transient definitions and cycles , and the FCG rate . The stability calculations in WCAP-13045 were reviewed based on the applicability of the fracture toughness for SLR in Section 3 of this report. The fatigue crack growth analysis in WCAP-13045 was reviewed based on for FCG rates , stresses, and transient definitions and cycles in Section 4. The final conclusions of this report are provided in Section 5 , with all cited references provided in Section 6 . Appendix A of this report also provides the ASME Code Section XI Code Case N-481 , for reference , which was approved and published in March 1990 , and later annulled in March 2004 , as the requirements of the code case were incorporated in the 2000 Addenda and 2008 Addenda of the ASME Code Section XI IWB-2500 . This document contains Westinghouse Electric Company LLC proprietary information and data which has been identified by brackets. Coding (a , c , e) associated with the brackets sets forth the basis on which the information is considered proprietary. These code letters are listed with their meanings in BMS-LGL-84

[12] . PWROG-17033

-NP June 2018 Revision 1 WESTINGHOUSE NON-PROPRIETARY CLASS 3 2-1 2 BACKGROUND Plants have used the generic fracture mechanics evaluation performed in WCAP-13045 to comply with the requirements of ASME Code Case N-481 for the license renewal applications to extend plant operations to 60 years. Before Code Case N-481 was annulled and the requirements of the Code Case were incorporated into ASME Code Section XI, utilities were furthermore required to perform a plant-specific evaluation using the generic fracture mechanics analysis in WCAP-13045 to demonstrate compliance with N-481. Following the incorporat i on of Code Case N-481 into Section XI, no further fracture mechanics evaluations have been performed as plants were not required to perform volumetric or routine in t ernal visual examinations of RCP casing welds , and the only ASME Code Section XI inspection requirement is to perform external surface examinations of the pump casing welds and visual examinat i ons of the internal surfaces of the pump casing welds when the RCP is disassembled for other reasons (e.g. maintenance or refurbishments). The thermal aging and fatigue crack growth methodology in WCAP-13045 was reviewed and is provided in this TR to demonstrate that the time-limiting aging analysis aspects of WCAP-13045 continue to remain bounding and acceptable for 80 years of plant life. The NRC has approved several plant license renewal applications for 60 years of operation that utilized the generic fracture mechanics analyses and conclusions in WCAP-13045 as discussed below: 1. The NRC Safety Evaluation Report (Section 4.4.4) for Salem Units 1 and 2 [13] discusses the use of the generic fracture mechanics analysis in WCAP-13045 to meet the requirements of ASME Code Case N-481 for a 60 year license renewal. The NRC staff concluded that the generic analysis in WCAP-13045 is applicable to the Salem design of the RCP casings. The generic analysis, WCAP-13045 , bounds the specific analysis , WCAP-16957-P

[17], as approved by the staff in the SER [1 3]. The analysis was shown to remain valid for extended operation. 2. In the 60 year license renewal NRC Safety Evaluation Report for D.C. Cook Units 1 and 2, NUREG-1831 , Section 4.7.2 [14], the NRC staff discusses the use of WCAP-13045 to satisfy the requirements of ASME Code Case N-481 based on a plant-specific analysis, WCAP-13128

[18]. In Section 4.7.2.4 of [14], the NRC concludes that the time-l i mited aging analysis (TLAA) regarding ASME Code Case N-481 that was provided i s acceptable.

3. The 60 year license renewal Safety Evaluation Report (Section 4.3.2.10) for Diablo Canyon Units 1 and 2 [15] discusses that WCAP-13045 was used to demonstrate compliance with Code Case N-481 based on a plant-specific evaluation , WCAP-13895

[19]. In Section 4.3.2.10.4 of [15], the NRC concludes that it was shown that the aging of the RCP pump casings will be adequately managed for extended operation. 4. Based on the Sequoyah 60 license renewal Safety Evaluation Report [16], the NRC concluded that the plant 's LRA did not need to include a TLAA related to Code Case N-481 because the licensing basis is per the ASME Code Section XI Edition, which no longer relies on N-481 for ISi (in-service inspection interval) requirements. Thus , i t was PWROG-17033-NP J u ne 2018 Rev i sion 1 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * **

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  • WESTINGHOUSE NON-PROPRIETARY CLASS 3 2-2 not necessary to perform any TLAA analysis for RCP pump casings and N-481 , as it does not meet Criterion 4 or 6 in 10 CFR 54.3(a) . In summary , WCAP-13045 has been reviewed by NRC to support 60 year license renewal applications for several plants that used Code Case N-481 as a basis for their ISi examination programs. This report reviews the TLAA aspects of WCAP-13045 to demonstrate its continued applicability for 80 years of plant operation . 2.1 OPERATING EXPERIENCE AND APPLICATION OF LATEST FRACTURE TOUGHNESS DATABASE The Westinghouse RCP casings have an operating history that demonstrates the inherent flaw tolerance and structural stability of the pump casings. No detectable service-induced flaws nor discernable degradation of the cast austenitic stainless steel (CASS) pump casings and welds in the Westinghouse pump operating history have been identified . The fracture mechanics evaluation contained in this TR (later discussed in Section 3) considers the latest fracture toughness correlations that have been developed for the CASS pump casings. The end of life fracture toughness properties for the pump casing materials are determined based on NUREG/CR-4513, Revision 2, "Estimation of Fracture Toughness of Cast Stainless Steels during Thermal Aging in LWR systems ," by Omesh Chopra, published in May 2016 [11] . Revision 2 of NUREG/CR-4513 provides a large database for CASS material and thermal aging, and builds on the work performed in 1994 for Revision 1 of NUREG/CR-4513.

In 1994, the Argonne National Laboratory (ANL) completed an extensive research program to evaluate the extent of thermal aging of cast stainless steel materials

[11]. The ANL research program measured mechanical properties of cast stainless steel materials after they had been heated in controlled ovens for long periods of time. ANL compiled a database , both from data within ANL and from international sources, of approximately 85 compositions of cast stainless steel exposed to a temperature range of 290-400°C (550-750°F) for up to 58 , 000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> (6.5 years) . In 2015 , the work done by ANL was augmented , and the fracture toughness database for CASS materials was aged to 100 , 000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> at 290-350°C (554-633°F). The methodology for estimating fracture properties has been extended to cover CASS materials with a ferrite content of up to 40%. From this database in NUREG/CR-4513, Revision 2 , ANL developed lower bound correlations for estimating the extent of thermal aging of cast stainless steel [11]. ANL developed the fracture toughness estimation procedures by correlating data in the database conservatively. After developing the correlations , ANL validated the estimation procedures by comparing the estimated fracture toughness with the measured value for several cast stainless steel plant components that were removed from service. The procedure developed by ANL in [11] was used for the end of life fracture toughness values contained in this TR. The ANL research program was sponsored and the procedure was accepted by the NRC . PWROG-17033-NP June 2018 Revision 1 WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-1 3 STABILITY ANALYSIS AND FRACTURE TOUGHNESS 3.1 FRACTURE TOUGHNESS DETERMINED IN WCAP-13045 The fracture mechanics integrity evaluation is based on the Elastic Plastic Fracture Mechanics (EPFM) methodology as discussed in Sections 10 and 11 of WCAP-13045

[1]. T he EPFM is determined for a postulated 1 /4T (1 /4 thickness) flaw size with a six-to-one (6: 1) aspect ratio. This particular flaw size is consistent with the guidelines of Code Case N-481 Part (d)(5). The location of the postulated 1/4T flaws are either at highest stressed region, regions of significant stress concentrations , or locations in welds not affected by discontinuities such as nozzles. Additional discussion on flaw postulation is contained in Section 9 of WCAP-13045. The criterion for establishing stability is based on the fracture toughness of the pump casings, as well as the tearing modulus, T, as discussed in Section 10.4 of WCAP-13045 and shown below: A crack is stable if either 1) Japplied < J1c or if 2) Japplied > J1c then T applied < T material and Japplied :5 Jma x imum The applied toughness (Japplied or Japp) and applied tearing modulus (Tapplied or Tapp) are calculated with the EPRI handbook methodology

[1 O], based on various combinations of loading parameters and material properties for the various pump designs as discussed in WCAP-13045.

The Japp and Tapp are not impacted by a design life to 80 years as they are not time dependent; however, the fracture toughness material parameters such as the crack initiation toughness (J1c), which is based on a J-integral resistance curve , the maximum fracture toughness (Jmax i mum or Jmax), and the tearing modulus (T mater i al or T mat) need be reviewed to confirm that these parameters are not impacted by 80 years of operation.

The end of service (40 years) fracture toughness (J1c , T mat, and Jmax) of the pump casings are calculated in Section 5 of WCAP-13045

[1]. The lower bound toughness criteria selected from among all the pump casing (and welds) and models (Models 63, 70 , 93, 93A , 93A-1, 930 , 100A, and 1000) are given in Table 5-1 of WCAP-13045. The minimum fracture toughness values based on the most limiting SA-351 CF8M component from Table 5-1 of WCAP-13045 which were considered in this TR are shown in Table 1 below. The fracture toughness properties for CF8M in WCAP-13045 bound the CF8 material , because the thermal aging is more limiting for the CF8M material than the CF8 material.

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  • WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-2 Table 1: End-of-Service Fracture Toughness from WCAP-13045 (Table 5-1) [1] Material J 1 c (in-lb/in 2) T mat (dimensionless)

Jma x (in-lb/in 2) Model 93 SA-351 CF8M [ t , c , e [ rc , e [ rc , e C hemistry: [ rc , e Note: The values J, c, T mat, and Jma x shown for the CF8M material above are the same values in Table 5-1 and on page A-30 of WCAP-13045 . The fracture toughness data in Table 1 (from Table 5-1 of WCAP-13045) is based on the chemistry data from Appendix A (page A-30) of WCAP-13045. Based on the chemistry of the limiting heat of cast austenitic stainless steel (i.e., Silicon (Si), Chromium (Cr), Molybdenum (Mo), Nickel (Ni), Carbon (C), Manganese (Mn), and Nitrogen (N) in percent weight , and percent delta ferrite), the fracture toughness is calculated in accordance with WCAP-10931

[5], Slama [6], and WCAP-10456

[7] . Based on the results in Slama [6] and WCAP-10456

[7], the minimum (saturated) fracture toughness properties were obtained after [ rc , e Therefore , the fracture toughness properties shown in Table 1 (per Table 5-1 of WCAP-13045) are at the full-aged saturated condition material values, and are therefore applicable to 80 years of service life, because the resulting minimum (saturated) properties are reached by [ r c, e Therefore , the EPFM stability analysis and conclusions in WCAP-13045

[1], based on the saturated fracture toughness values in Table 1 , are applicable for 80 years of operation . The minimum fracture toughness values based on Table 5-1 of WCAP-13045 (as shown in Table 1) were compared with the latest fracture toughness correlations for thermal aging of cast austenitic stainless steel CF8M material per NUREG/CR-4513 , Revision 2 [11]; see Section 3.2 below. This comparison confirms that the fracture toughness values in WCAP-13045

[1] are bounding and applicable to the 80 year design life . P WROG-17033-NP June 2018 Revision 1 WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-3 3.2 FRACTURE TOUGHNESS BASED ON NUREG/CR-4513, REVISION 2 In this section of the TR , a calculation is performed to determine the J 1 c , T mat and Jma x values based on latest industry guidelines and fracture toughness correlations for thermal aging of cast austenitic stainless steel from NUREG/CR-4513 Revision 2 [11] for the most limiting CF8M pump casing material , us i ng the limiting heat specific chemistry values provided in Table 1 (originally from WCAP-13045). The fracture toughness values calculated in accordance with NUREG/CR-4513 will be compared to the values determined in Table 1 , from WCAP-13045. This comparison of fracture toughness values will demonstrate if the toughness properties from WCAP-13045 remain bounding and acceptable for 80 years. Note that the impact of thermal aging on the CF8 fracture toughness properties is less t han that for the CF8M material; therefore the evaluation herein only considered the CF8M material because it bounds the fracture toughness values for the CF8 material.

The following equations are contained in NUREG/CR-4513, Revision 2 [11] and are applicable to the CF8M material.

The calculated fracture toughness values based on [11] are shown in Table 2. Creq = Cr+ 1.21 (Mo) + 0.48(Si) -4.99 = (Chromium equivalent)

Ni e q = (Ni) + 0.11 (Mn) -0.0086(Mn)2

+ 18.4(N) + 24.S(C) + 2. 77 = (Nickel equivalent)

Oc =100.3(Creq / Nieq )2-170.72(Cr e q / Nieq )+74.22 = (Fer r ite Content) The elements are in percent weight and Oc is ferrite in percent volume. The saturation room temperature (RT) impact energies for the cast stainless steel materials are determined from the chemical composition. For CF8M steel with < 10% Ni, the saturation value of RT impact energy Cvsat (J/cm 2) is the lower value determined from: log10CVsat

= 0.27 + 2.81 exp (-0.022$) where the material parameter

$ is expressed as: $ = o c (Ni + Si + Mn)2(C + 0.4N)/5.0 and using: log 10 CVsat = 7.28 -0.011 Oc -0.185Cr -0.369Mo -0.451 S-0.007Ni -4.71 (C + 0.4N) For CF8M steel with 10% Ni, the saturation value of R T impact energy Cvsat (J/cm 2) is the lower value determined from: log10CVsat

= 0.84 + 2.54 exp (-0.047$) where the material parameter

$ is expressed as: $ = oc (Ni + Si + Mn)2(C + 0.4N)/5.0 and using: log 10 Cvsa t = 7.28-0.011 oc-0.185Cr-0.369Mo -0.451S i -0.007Ni-4.71(C + 0.4N) PWROG-17033-NP June 2018 Revision 1 * * * * * * * * * * * * * * * * * * * *1 * * *1 * * * * * * *I * * * * * * * * * * * * *

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  • WESTINGHOUSE NON-PROPRIETARY CLASS 3 The saturation J-R curve at RT , for static-cast CF8M steel is given by: Jd = 1.44 (CV sa t) 1 35 (~at for CV sat < 35 J/cm 2 Jd = 16 (CVsa1)0 6 7 (~at for CV sat 35 J/cm 2 n = 0.20 + 0.08 109 1 0 (CVsat) where J d is the "deformation J " in kJ/m 2 and ~a is the crack extension i n mm . 3-4 The saturation J-R curve at 290-320°C (554-608°F), for static-cast CF8M steel is given by: Jd = 5.5 (Cvsai>° 98 (~at for CV s a t < 46 J/cm 2 Jd = 49 (CVsa1)°-41 (~at for CV s a t 46 J/cm 2 n = 0.19 + 0.07 10910 (CV s at) where Jd is the "deformation J " in kJ/m 2 and ~a is the crack extension in mm . r c , e The tearing modulus , T material is calculated by T = dJ/da
  • El a/, where dJ/da is the slope of the J-R curve , Eis elastic modulus , and a t is the flow strength (average of the yield strength and ultimate strength). Applying the NUREG/CR-4513 , Revision 2 [11] correlations , the fracture toughness properties are given in Table 2 . NUREG/CR-4513, Revision 2 discusses that the fracture toughness correlations used for the full aged condition are applicable to plants that have been operating for greater than or equal to 15 Effective Full Power Years (EFPY) for the CF8M material.

The Westinghouse NSSS plants have been operating for greater than 15 EFPY; therefore , the use of the fracture toughness correlations discussed above is applicable to the fully aged or saturated conditions . Therefore , the fracture toughness values based on the original methodology in WCAP-13045 are limiting (see Table 1) as compared to the fracture toughness values based on NUREG/CR-4513 (see Table 2). By calculating the latest industry correlation for the fracture toughness values for aged cast austenitic stainless steel from NUREG/CR-4513 , it can be concluded that the aged toughness values in Table 1 (from Table 5-1 of WCAP-13045) are bounding and limiting for 80 years of operation . PWROG-17033-NP June 2018 Revision 1 WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-5 Table 2: NUREG/CR-4513

[11] Fully-Aged (Saturated)

Fracture Toughness Material J1 c (in-lb/in 2) T ma t (dimensionless)

Jm ax (in-lb/in 2) Model 93 SA-351 CF8M [ t , c , e [ r c , e [ rc , e Chemistr:y (from Table 1 ): [ r c , e ASME Code properties are used for E (modulus of elast i c i ty) = 25.6 x 10 6 ps i and Y i eld Strength = 19 , 350 psi. Ult i mate strength=

67 , 000 psi per Table 6-3 of WCAP-13045 , which is a close approximation to t he ASME Code values. The values are for the cold leg temperature , approximately 550°F. PWROG-17033

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  • WESTINGHOUSE NON-PROPRIETARY CLASS 3 4-1 4 FATIGUE CRACK GROWTH ANALYSIS Two fatigue crack growth analyses were originally performed in Section 12 of WCAP-13045

[1], one for a postulated crack in the highest stressed outlet nozzle knuckle in a Model 93A pump casing and the other in the highest stressed outlet nozzle knuckle in a Model 93 pump casing . The FCG analysis for the Model 93A pump was perfo r med prior to the publication of the stainless steel FCG rate in the ASME Code Section XI; therefore , the FCG rate in [Equation

1) from [9] was initially considered in WCAP-13045. However , the FCG analysis for a Model 93A RCP was calculated based on [Equation 2], which was an updated version of [Equation 1] for stainless steel in a water env i ronment. [Equation
1) in WCAP-13045 was provided for informat i on purposes and is as follows: :~ = 5.4 x 10-1 2 (Keff)4.4 8 (inches/cycle)

Keff = K m ax C 1-R)0*5 Kma x and Kmin i s in units of ks i v'rn [Equation 1] The FCG rate used for the Model 93 postulated flaw in [1] was based on Figure C-3210-1 of Article C-3000 of Section XI of the ASME Code (1989 Edition) and is shown i n Equation 2 below: :~ = C F S E (LlK)3*30 (inches/cycle)

[Equation

2) Where: C = 2.42 x 10-2 0 , F = 1 for temperatures below 800°F , S = the R ratio correction (see the definition of 'S ' in Equation 3 below), R = the ratio of the minimum stress intensity factor (SIF) to the maximum SIF , LlK = the range of stress intensity factors (psi ../i n), and E = 2 based on stainless steel in water [8] . The current NRC approved 2013 Edition of the ASME Code Section XI Appendix C fatigue crack growth for stainless steel is shown below. A factor of 2 is applied to the da/dN rate to account for the environmental effects of a postulated flaw in water as d i scussed in [8]: :~ = 2*C 0 S (~K 1)3*3 (inches/cycle) where C 0 = 10" [-10.009 + 8.12x10-4 T-1.13x10-6 T 2 + 1.02x10-9 T 3) T = Temperature

(°F) = 550°F (see Table 11-1 and Table 11-6 of [1]) [Equation

3) S = 1.0 for R :s; 0, S = 1 + 1.8R when O < R < 0.79 , and S = -43.35 + 57.97R when 0.79 < R < 1 ~K 1 is in units of ksi ../i n , R = Km i n/K m a x There are no significant differences between the current stainless steel FCG rate in water , [Equation
3) and the FCG rate used in WCAP-13045 [1], and [Equation
2) for the Model 93 PWROG-17033-NP June 2018 Revision 1 WESTINGHOUSE NON-PROPRIETARY CLASS 3 4-2 postulated flaws. The difference between the current stainless steel FCG rate in water [Equation
3) and the FCG rate considered in WCAP-13045 , [Equation 1] for the Model 93A postulated flaw is also insignificant.

Therefore, the existing FCG rates in Section 12 of WCAP-13045 are acceptable based on current industry standards for fatigue crack growth for stainless steel material in a water environment.

Other inputs required for an FCG analysis are the stress intensity factors , stresses , transient cycles and transient definitions. The stress intensity factor (SIF) correlations used for the FCG analysis in WCAP-13045 are consistent with the current correlations provided in 2013 Edition of ASME Code Section XI Appendix A. The transient stresses used in the FCG analysis are generic and encompass the various pump models. These stresses are not impacted for 80 years of operation , as plant operations for this extended period will not vary greatly from current operations. The number of predicted cycles for 80 years of service for each applicable transient is assumed to be bounded by the number of transient cycles considered in the 40 year life of the plant and shown in Table 12-2 of WCAP-13045.

However, to ensure conservatism in the results presented in this TR, the FCG cycles for 40 years were doubled for 80 years to account for any large differences in the transient cycles. It was concluded that the final flaw size would still be less than the stability flaw size for this region as discussed below. The calculated FCG for four flaw sizes in the outlet nozzle knuckle region of a Model 93A pump casing is given in Table 12-1 of WCAP-13045. The calculated FCG for three flaw sizes in the outlet nozzle knuckle region of a Model 93 pump casing is given in Table 12-3 of WCAP-13045. One of the flaw size cases for FCG was for an initial flaw depth of 0.3 "; this particular flaw depth was the maximum acceptable flaw size in the Acceptance Standards in Table IWB-3518-2 (for pressure retaining welds in pump casings) up to the 2007 Edition of the ASME Code Section XI. The flaw depth of 0.3 " is also the maximum acceptable flaw size in the Acceptance Standards Table IWB-3519.2-2 (for pump casings) in later editions of the ASME Code Section XI. Therefore , the flaw depth of 0.3 " was an important flaw size case to consider in WCAP-13045 for the flaw tolerance evaluation , and any actual as-found flaws larger than this depth would need to be evaluated based on fracture mechanics. The other FCG postulated flaw size cases considered in WCAP-13045 were provided as sensitivity studies to demonstrate that the flaws do not grow significantly over time. Based on the fatigue crack growth analyses in Tables 12-1 and 12-3 of WCAP-13045 , the flaw depth of 0.3 " grows to a maximum value of [ rc , e over 40 years of service. All other inputs for the FCG analysis (stress intensity factors , stress , transient cycles and transient definitions) are bounded by , or are similar to , the inputs of WCAP-13045, then the fatigue crack growths for 80 years are similar to or less than the crack growth in Table 12-1 and Table 12-3 of WCAP-13045 for 40 years. Additionally, if the number of transient cycles for 40 years are doubled for 80 years to account for any large differences in the transient cycles , then the final flaw size would continue to be less than the minimum stability flaw size of 1/4T flaw depth ([ J8'c , e in Table 11-6 of WCAP-13045), which is associated with the location of the highest stressed region. Therefore, the FCG analysis provided in Section 12 of WCAP-13045 remains valid for 80 years of operation. PWROG-17033-NP June 2018 Revision 1 * * * * * * * * * * * * * * * * * * * .I * * * * * * * * * * * * * * * * * * * * * * *

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  • I. ,. I. _I WESTINGHOUSE NON-PROPRIETARY CLASS 3 5-1 5 CONCLUSIONS The objective of this report is to review the RCP casing fracture mechanics integrity evaluations and the fatigue crack growth analysis contained in WCAP-13045 (1], and to confirm that they remain valid for 80 years of service . Section 3.1 discussed the most limiting pump casing CF8M fracture toughness and the tearing modulus used in the WCAP-13045 J-integral stab i lity evaluations (EPFM). The WCAP-13045 fracture toughness determinations are applicable to 80 years of service because the fracture toughness parameters are at full-aged saturated conditions , therefore , any additional aging past 40 years does not have an impact on the fracture toughness parameters.

Section 3.2 compared the minimum fracture toughness in WCAP-13045 with the latest industry toughness correlations in NUREG/CR-4513 , Revision 2 (11]. Based on the conclusions in Section 3.2 , it is demonstrated that the fracture toughness values in WCAP-13045 are less than (more conservative and limiting) than the fracture toughness values in NUREG/CR-4513. Therefore , as compared with the current industry standards , the fracture toughness values in WCAP-13045 are limiting and applicable to 80 years of operation. Thus , the EPFM analysis for the pump casings contained in WCAP-13045 is valid for 80 years because the minimum fracture toughness used in the stability analysis is applicable to 80 years of service life . A qualitative evaluation for the fatigue crack growth evaluation was performed in Section 4 of this report for the pump casings. It was determined that the current FCG rate for stainless steel in a water environment based on the 2013 Edition of the ASME Code Section XI , when compared to the rates used in WCAP-13045 , are comparable and there will be an insignificant impact on the crack growth analysis. Furthermore , the stresses used in the FCG analysis are generic and envelop the various pump designs. Additionally , these stresses do not change for 80 years of operation , as they are not time dependent.

The stress intensity factors used in the FCG analysis are consistent with the current industry standards for similar FCG evaluations. The transient definitions in the FCG analysis are also not expected to change over the design life, and the cycles used in the WCAP-13045 are assumed to bound the predicted 80 year transient cycles. Finally , there is sufficient margin between the final crack growth and the flaw size used for stability; therefore , even if the 40 year transient cycles are doubled for 80 years of operation , the final flaw size after FCG will be less than the stability flaw size , 1/4T flaw depth , for the stability analysis in WCAP-13045 . In conclusion , the fracture mechanics integrity evaluation in WCAP-13045 (1] for pump casings is applicable to 80 years of design life. The fracture mechanics evaluation for SLR in this TR justifies continuing to perform visual inspections , in lieu of volumetric inspections , for pump casings as incorporated in ASME Code Section XI. PWROG-17033-NP June 2018 Revision 1 WESTINGHOUSE NON-PROPRIETARY CLASS 3 6-1 6 REFERENCES

1) Westinghouse Document , WCAP-13045 , "Compliance to ASME Code Case N-48 1 of the Primary Loop Pump Casings of Westinghouse Type Nuclea r Steam Supply System , " September 1991. 2) ASME Boiler and Pressure Vessel Code,Section XI , "Rules for lnservice I nspect i on of Nuclear Power Plant Components." 3) Code Case N-481 , "Alternative Examination Requirements for Cas t Austenitic Pump Casings ,"Section XI , Division 1 , Approval Date: March 5 , 1990. 4) PWROG Project Author i zation , PA-MSC-1498 , Revision 0 , "Update for Subsequent License Renewal: WCAP-13045 , 'Compliance to ASME Code Case N-481 of the Primary Loop Pump Casings of Westinghouse Type Nuclear Steam Supply Systems '." 5) Westinghouse Document , WCAP-10931 , Revision 1 , "Toughness Criteria for Thermally Aged Cast Stainless Steel ," July 1986. 6) Slama, G., Petrequin, P., Masson , S. H. and Mager , T. R., "Effect of Aging on Mechanical Properties of Austenitic Stainless Steel Casting Welds ," presented at SMIRT 7 Post Conference Seminar 6 -Assuring Structural Integrity of Steel Reactor Pressure Boundary Components , August 29/30 , 1983 , Monterey , CA 7) Westinghouse Document , WCAP-10456, "The Effects of Thermal Aging on Structural Integrity of Cast Stainless Steel P i ping for Westinghouse Nuclear Steam Supply Systems ," November 1983. 8) "Evaluation of Flaws i n Austenitic Steel Piping ," Trans. ASME , Journal of Pressure Vessel Technology , Vol. 108 , pp. 352-366 , 1986. 9) Bamford , W. H., "Fat i gue Crack Growth of Stainless Steel Piping in a Pressurized Water Reactor Environment

," Trans ASME , Journal of Pressure Vessel Technology , Feb r uary 1979. 10) Kumar , V., German , M. D. and Shih , C. P., "An Engineering Approach for Elast i c-Plastic Fracture Analysis ," EPRI Report NP-1931 , Project 1237-1 , Electr i c Power Research Institute , July 1981. 11) 0. K. Chopra , "Estimation of Fracture Toughness of Cast Stainless Steels Du r ing Thermal Aging in LWR Systems , " NUREG/CR-4513 , Revision 2 , U.S. Nuclear Regulatory Commission , Washington , D.C., May 2016. 12) BMS-LGL-84 , Revision 0.00 , "Protection of Proprietary Information Regarding Submittals to the USNRC including Safety Analysis Reports for Commercial Nuclear Power Plants ," Effective Date: April 15 , 2017. 13) U.S. Nuclear Regulatory Comm i ssion , "Safety Evaluation Report Related t o the License Renewal of Salem Nuclear Generating Station ," Docket Numbers 50-272 and 50-311 , March 2011. (NRC ADAMS Accession No. ML 110900295)

14) U.S. Nuclear Regulatory Commission , NUREG-1831 , "Safety Evaluation Report Related to the License Renewal of the Donald C. Cook Nuclear Plant , Units 1 and 2 ," Docket Nos. 50-315 and 50-316 , July 2005. (NRC ADAMS Accession No. ML052230442)

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  • I. 'e * * ,. 1* WESTINGHOUSE NON-PROPRIETARY CLASS 3 6-2 15) U.S Nuclear Regulatory Commission , "Safety Evaluation Report Related to the License Renewal of Diablo Canyon Nuclear Power Plant , Units 1 and 2 ," Docket Nos. 50-275 and 50-323 , June 2011. (NRC ADAMS Accession No. ML 11153A 103) 16) U.S. Nuclear Regulatory Commission , NUREG-2181 , "Safety Evaluation Report Related to the License Renewal of Sequoyah Nuclear Plant , Units 1 and 2 ," Docket Nos. 50-327 and 50-328 , July 2015. (NRC ADAMS Accession No. ML 15187A206)
17) Westinghouse Document , WCAP-16957-P , "A Demonstration of Applicability of ASME Code Case N-481 to the Primary Loop Pump Casing of Salem Generat i ng Station Units 1 and 2 for the License Renewal Program ," March 2009 . 18) Westinghouse Document , WCAP-13128 , "A Demonstration of Compliance of the Primary Loop Pump Casings of the D. C. Cook Units 1 and 2 to ASME Code Case N-481 ," March 1992 . 19) Westinghouse Document , WCAP-13895 , "A Demonstration of Applicability of ASME Code Case N-481 to the Primary Loop Pump Casings of the Diablo Canyon Nuclear Power Plants Units 1 and 2 ," October 1993 . PWROG-17033-N P June 2018 Revision 1 WESTINGHOUSE NON-PROPRIETARY CLASS 3 A-1 APPENDIX A : ASME CODE SECTION XI CODE CASE N-481 a , c , e PWROG-17033-NP June 2018 Revision 1 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
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