ML13259A120

Oconee Nuclear Station, Units 1, 2 & 3 - Response to Request for Additional Information (RAI) Regarding License Amendment Request to Update Pressure-Temperature Limit Curves License Amendment Request (LAR) No. 2012-10, Supplement 1

ML13259A120
Person / Time
Site:	Oconee
Issue date:	09/10/2013
From:	Batson S L Duke Energy Carolinas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
LAR-12-10, Supplement 1
Download: ML13259A120 (37)

Text

DUKE Enclosure 2 to this letter contains proprietary information.

Vce PrasinEnIENEDRGY Withhold From Public Disclosure Under 10 CFR 2.390.Upon removal of Enclosure 2 this letter is uncontrolled.

Oconee Nuclear StationDuke EnergyON01VP 1 7800 Rochester HwySeneca, SC 29672o: 864.873.3274 f 864.873.4208 Scott.Batson@duke-energy.com 10 CFR 50.90September 10, 2013ATTN: Document Control DeskU. S. Nuclear Regulatory Commission 11555 Rockville PikeRockville, MD 20852-2746

Subject:

Duke Energy Carolinas, LLCOconee Nuclear Station (ONS), Units 1, 2, and 3Docket Numbers 50-269, 50-270, and 50-287Renewed Operating License Numbers DPR-38, DPR-47, and DPR-55Response to Request for Additional Information (RAI) regarding LicenseAmendment Request to Update Pressure-Temperature Limit CurvesLicense Amendment Request (LAR) No. 2012-10, Supplement 1On February 22, 2013, Duke Energy Carolinas, LLC (Duke Energy) submitted a LicenseAmendment Request (LAR) requesting the Nuclear Regulatory Commission (NRC) approve newpressure-temperature (P-T) limit curves applicable to 54 effective full power years (EFPY) toreplace the 33 EFPY P-T limit curves in Technical Specification (TS) 3.4.3 and approvechanges to the operational requirements for unit heatup and cooldown in TS Tables 3.4.3-1 and3.4.3-2.

By letter dated June 21, 2013, NRC requested Duke Energy to provide additional information associated with the LAR. By electronic mail dated August 16, 2013, the NRCgranted an extension to the due date for this response to September 10, 2013, to allow DukeEnergy time to investigate an AREVA NP, Inc. (AREVA) notification made on August 16, 2013,associated with a potential deficiency in the current 33 EFPY and proposed 54 EFPY P-T limitcurves for ONS Unit 3.By letter dated August 16, 2013, AREVA notified Duke Energy that AREVA is evaluating issuesunder its Corrective Action Program (CAP) that indicate that the current P-T curves for ONSUnit 3 may be deficient.

This deficiency was discovered during AREVA's preparation ofresponses to NRC RAIs on the proposed 54 EFPY P-T curves. During preparation of the RAIresponses, AREVA reviewed the basis for the generic values to assess their applicability to theextended beltline reactor pressure vessel (RPV) components.

As a result of this review,AREVA determined that existing generic values for initial reference temperature for nil-ductility transition (RTNDT) and copper content, while compliant with existing NRC guidance andregulations, may not have been appropriate.

AREVA identified more limiting adjustedreference temperature (ART) input values using material data believed to be more appropriate for the ONS Unit 3 Lower Nozzle Belt (LNB) forging than the generic material data historically www.duke-energy.com Enclosure 2 to this letter contains proprietary information.

Withhold From Public Disclosure Under 10 CFR 2.390.Nuclear Regulatory Commission Upon removal of Enclosure 2 this letter is uncontrolled.

September 10, 2013Page 2applied.

Use of the more limiting ART data impacts the ONS Unit 3 P-T curves, specifically Figure 3.4.3-7 and Figure 3.4.3-8 in the ONS Technical Specifications.

As a near term conservative

measure, AREVA recommended limiting heat-up and cool-down P-T curves by using the most limiting composite curve established by the Surge Line LimitCurve and the current ONS Unit 3 Low Temperature Overpressure Protection (LTOP) limit toensure safe operation.

This issue was entered into the Duke Energy CAP and appropriate conservative measures have been implemented until longer term corrective actions can becompleted.

AREVA subsequently confirmed that this deficiency does not impact the RAI responses for the54 EFPY P-T LAR since the RAIs are directed toward extended beltline materials.

AREVA'sassessment of extended beltline materials is not impacted by this issue. However, the ONSUnit 3 P-T Curves (33 EFPY and 54 EFPY) need to be revised.

The 33 EFPY P-T curves wererevised on August 23, 2013. AREVA is currently revising the 54 EFPY P-T curves. The use ofthe new 33 EFPY P-T curves is being controlled administratively until such time that the54 EFPY P-T curves are approved and implemented at ONS. Duke Energy will submit arevision to the 54 EFPY P-T Curve LAR, which includes revised P-T curves for ONS Unit 3, byOctober 31, 2013.Enclosures 1 and 2, which are non proprietary and proprietary respectively, provide therequested information.

Enclosure 2 contains information that has been classified as proprietary by AREVA. The affidavit in Enclosure 3 sets forth AREVA basis on which the proprietary information may be withheld from public disclosure by the NRC pursuant to 10 CFR 2.390. Alist of Regulatory Commitments is provided in Enclosure 4.If there are any additional questions, please contact Boyd Shingleton, ONS Regulatory Affairs,at (864) 873-4716.

I declare under penalty of perjury that the foregoing is true and correct.

Executed onSeptember 10, 2013.Sincerely, Scott L. BatsonVice President Oconee Nuclear Station Enclosure 2 to this letter contains proprietary information.

Withhold From Public Disclosure Under 10 CFR 2.390.Nuclear Regulatory Commission Upon removal of Enclosure 2 this letter is uncontrolled.

September 10, 2013Page 4bcc w/

Enclosures:

D. E. WhitakerJ. M. ShupingS. N. Severance L. S. NicholsT. L. Patterson E. L. AndersonM. E. BaileyR. D. Hart -CNSJ, N. Robertson

-MNSD. B. Alexander-NRI&IAD. R. Westcott

-CR3L. J. Grzeck -BNPD. H. Corlett -HNPW.R. Hightower-RNPRegulatory Affairs Manager -ONSNSRB, EC05NELL, ECO50File -T.S. WorkingONS Document Management Enclosure 2 to this letter contains proprietary information.

Withhold From Public Disclosure Under 10 CFR 2.390.Nuclear Regulatory Commission Upon removal of Enclosure 2 this letter is uncontrolled.

September 10, 2013Page 3cc w/

Enclosures:

Mr. Victor McCree, Regional Administrator U. S. Nuclear Regulatory Commission

-Region IIMarquis One Tower245 Peachtree Center Ave., NE, Suite 1200Atlanta, GA 30303-1257 Mr. Richard Guzman, Senior Project Manager(by electronic mail only)Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission 11555 Rockville PikeMail Stop O-8G9ARockville, MD 20852Mr. Eddy CroweSenior Resident Inspector Oconee Nuclear SiteMs. Susan E. Jenkins, ManagerRadioactive

& Infectious Waste Management Division of Waste Management South Carolina Department of Health and Environmental Control2600 Bull St.Columbia, SC 29201 License Amendment Request No. 2012-10, Supplement 1September 10, 2013ENCLOSURE INON PROPRIETARY VERSIONDuke Energy Response toNRC Request for Additional Information (RAI)

Controlled Doc.umnent AAREVAResponse to NRC Request for Additional Information Regarding License Amendment Request to Update Pressure-Temperature Limit Curves for Oconee Units 1, 2, and 3ANP-3127Q1NP Revision 1August 2013AREVA NP Inc.(c) 2013 AREVA NP Inc.

C.,ontr.lled DocumentCopyright

© 2013AREVA NP Inc.All Rights Reserved ot b 'zed Docunnent AREVA NP Inc. ANP-3127Q1NP Revision 1Response to NRC Request for Additional Information Regarding License Amendment Reouest to Update Pressure-Temoerature Limit Curves for Oconee Units 1. 2. and 3 Page iNature of ChangesSection(s) orRevision Page(s)0 All1 Page v2.1.1 & 2.1.2.12.1.2.1.4 2.2.2Description and Justification Initial IssueAdded RCPB and SER to Nomenclature Minor editorial changesRemoved last sentence of first paragraph Classified the maximum 12.0 inch thickness of the nozzle beltforging as non-proprietary data Controlled DocumentAREVA NP Inc. ANP-3127Q1NP Revision 1Response to NRC Request for Additional Information Regarding License Amendment Reguest to Update Pressure-Temperature Limit Curves for Oconee Units 1. 2. and 3 Pace iiContentsLa.eLIST OF TABLES.............................................................................

IVLIS T O F F IG U R E S ..................................................................................................

..IVN O M E N C LA T U R E ...................................................................................................

..VA B S T R A C T ....................................................................................................................

V I

1.0 INTRODUCTION

AND SUMMARY ...................................................................

1-12.0 REQUESTS FOR ADDITIONAL INFORMATION (RAIS) ANDR E S P O N S E S ....................................................................................................

2 -12 .1 R A I-1 .......................................................................................................

2 -12.1.1 S tate m ent of R A I-1 .......................................................................

2-12.1.2 R esponse to R A I-1 .......................................................................

2-22.1.2.1 General Response to RAI-1 ............................................

2-22.1.2.1.1 Response to Item 1 of RAI-1 ........................

2-32.1.2.1.2 Response to Item 2 of RAI-1 ........................

2-42.1.2.1.3 Response to First Bullet of RAI-1 .................

2-42.1.2.1.4 Response to Second Bullet of RAI-1 ............

2-72.1.2.1.5 Response to Third Bullet of RAI-1 ................

2-82.1.2.2 C onclusion for RA I-1 ......................................................

2-82 .2 R A I-2 .......................................................................................................

2 -92.2 .1 S tatem ent of R A I-2 .......................................................................

2-92.2.2 R esponse to R A I-2 .......................................................................

2-92 .3 R A I-3 .....................................................................................................

2 -1 3 Controlled DocumentAREVA NP Inc. ANP-3127Q1NP Revision 1Response to NRC Request for Additional Information Regarding License Amendment Reauest to Update Pressure-Temperature Limit Curves for Oconee Units 1. 2. and 3 Paae iii2.3.1 Statem ent of RAI-3 .....................................................................

2-132.3.2 Response to RAI-3 .....................................................................

2-132 .4 R A I-4 .....................................................................................................

2 -142.4.1 Statem ent of RAI-4 .....................................................................

2-142.4.2 Response to RAI-4 .....................................................................

2-142 .5 R A I-5 .....................................................................................................

2 -1 42.5.1 Statement of RAI-5 .....................................................................

2-142.5.2 Response to RAI-5 .....................................................................

2-152 .6 R A I-6 .....................................................................................................

2 -1 62.6.1 Statem ent of RAI-6 .....................................................................

2-162.6.2 Response to RAI-6 .....................................................................

2-162 .7 R A I-7 .....................................................................................................

2 -1 72.7.1 Statem ent of RAI-7 .....................................................................

2-172.7.2 Response to RAI-7 .....................................................................

2-172.8 RAI-8 ...........................................

2-172.8.1 Statem ent of RAI-8 .....................................................................

2-172.8.2 Response to RAI-8 .....................................................................

2-1

83.0 REFERENCES

..................................................................................................

3-1 Controlled DocumentAREVA NP Inc. ANP-3127Q1NP Revision 1Response to NRC Request for Additional Information Regarding License Amendment Reauest to Uodate Pressure-Temperature Limit Curves for Oconee Units 1. 2. and 3 Paae ivList of TablesTable 2.8.2-1 Data Points for Figure 2.8.2-1 .............................................................

2-21Table 2.8.2-2 Data Points for Figure 2.8.2-2 .............................................................

2-22List of FiguresFigure 2.1.2-1 Composite Heatup P-T Curve for Oconee Unit 1 (Adjusted Figure 7-1 ofA N P -3 12 7 ) ..............................................................................................

2 -5Figure 2.1.2-2 Composite Cooldown P-T Curve for Oconee Unit I (from Figure 7-2 ofA N P -3 1 2 7 ) ..............................................................................................

2 -6Figure 2.2.2-1 RPV Configuration for Oconee Unit 1 ................................................

2-11Figure 2.2.2-2 RPV Configuration for Oconee Units 2 and 3 .....................................

2-12Figure 2.5.2-1 Location Adjusted Closure Head P-T Limits .......................................

2-15Figure 2.8.2-1 Corrected P-T Curve for Oconee Unit 1 Ramped Normal Heatup withR C P S tart at 100°F ...............................................................................

2-19Figure 2.8.2-2 Corrected P-T Curve for Oconee Unit 1 Ramped Normal Cooldown withD H R a t 19 0 °F .......................................................................................

2 -2 0 Controlled DocumentAREVA NP Inc. ANP-3127Q1NP Revision 1Response to NRC Request for Additional Information Regarding License Amendment Reauest to Update Pressure-Temperature Limit Curves for Oconee Units 1. 2. and 3 Paae vNomenclature AcronymARTASMEB&WEFPYLSTNRCONS (-1, -2,-3)PWRRAIRCPBRVRTNDTSERTLAADefinition Adjusted Reference Temperature American Society of Mechanical Engineers Babcock & WilcoxEffective Full Power YearsLowest Service Temperature United States Nuclear Regulatory Commission Oconee Nuclear Station (Unit 1, Unit 2, Unit 3)Pressurized Water ReactorRequest for Additional Information Reactor Coolant Pressure BoundaryReactor VesselReference Temperature for Nil-Ductility Transition Safety Evaluation ReportTime-Limited Aging Analysis Control ed DocumentAREVA NP Inc. ANP-3127Q1NP Revision 1Response to NRC Request for Additional Information Regarding License Amendment Reauest to Uodate Pressure-Temperature Limit Curves for Oconee Units 1. 2. and 3 Paae viABSTRACTAREVA Document ANP-3127, Revision 1, "Oconee Nuclear Station Units 1,2 & 3Pressure-Temperature Limits at 54 EFPY," was prepared by AREVA for Duke Energyand subsequently submitted to the Nuclear Regulatory Commission (NRC) by DukeEnergy. The NRC has issued the first set of Requests for Additional Information (RAls)on this submittal, and this report provides the answers for generic RAI 1 andapplication-specific RAIs 2 through 8.

Controlled DocumentAREVA NP Inc. ANP-3127Q1NP Revision IResponse to NRC Request for Additional Information Regarding License Amendment Reauest to Update Pressure-Temperature Limit Curves for Oconee Units 1. 2. and 3 Paae 1-

11.0 INTRODUCTION

AND SUMMARYAREVA Document ANP-3127, Revision 11, "Oconee Nuclear Station Units 1, 2 & 3Pressure-Temperature Limits at 54 EFPY," was prepared by AREVA for Duke Energy2and subsequently submitted to the NRC by Duke Energy .The NRC has issued thefirst set of Requests for Additional Information (RAIs)3 on this submittal, and this reportprovides the answers to those RAls.

Controlled DocumentAREVA NP Inc. ANP-3127Q1NP Revision 1Response to NRC Request for Additional Information Regarding License Amendment Request to Update Pressure-Temperature Limit Curves for Oconee Units 1. 2. and 3 Paae 2-12.0 REQUESTS FOR ADDITIONAL INFORMATION (RAIs) AND RESPONSES The NRC RAls are reproduced from Reference 3 in Sections 2.1.1 through 2.8.1. TheAREVA/Duke Energy responses are in Sections 2.1.2 through 2.8.2.2.1 RAI-12.1.1 Statement of RAI-1Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Appendix G, Paragraph IV.A states that, "The pressure-retaining components of the reactor coolant pressureboundary

[RCPB] that are made of ferritic materials must meet the requirements of theAmerican Society of Mechanical Engineers Boiler and Pressure Vessel Code [ASMECode, Section III], supplemented by the additional requirements set forth ... [inparagraph IV.A.2, "Pressure-Temperature (P-T) Limits and Minimum Temperature Requirements"]."

Therefore, 10 CFR Part 50, Appendix G requires that P-T limits bedeveloped for the ferritic materials in the reactor vessel (RV) beltline (neutron fluence *1 x 1017 n/cm2, E > 1 MeV), as well as ferritic materials not in the RV beltline (neutronfluence < 1 x 1017 n/cm2, E > 1 MeV). Further, 10 CFR Part 50, Appendix G requiresthat all RCPB components must meet the American Society of Mechanical Engineers Code (ASME Code),Section III requirements.

The relevant ASME Code, Section IIIrequirement that will affect the P-T limits is the lowest service temperature requirement for all reactor coolant pressure boundary RCPB) components specified in Section III,N1B-2332(b).

The P-T limit calculations for ferritic RCPB components that are not RV beltline shellmaterials may define P-T curves that are more limiting than those calculated for the RVbeltline shell materials due to the following factors:1. RV nozzles, penetrations, and other discontinuities have complex geometries that may exhibit significantly higher stresses than those for the RV beltline shellregion. These higher stresses can potentially result in more restrictive P-T limits,even if the reference temperature (RTNDT) for these components is not as high asthat of RV beltline shell materials that have simpler geometries.

Controlled DocumentAREVA NP Inc. ANP-3127Q1NP Revision 1Response to NRC Request for Additional Information Regarding License Amendment Reauest to Uodate Pressure-Temoerature Limit Curves for Oconee Units 1. 2. and 3 Paae 2-22. Ferritic RCPB components that are not part of the RV may have initial RTNDTvalues, which may define a more restrictive lowest operating temperature in theP-T limits than those for the RV beltline shell materials.

Consequently, please describe how the current P-T limit curves at 54 effective fullpower years (EFPY) for the Oconee units and the methodology used to develop thesecurves considered all RV materials (beltline and non-beltline) and the lowest servicetemperature of all ferritic RCPB materials, consistent with the requirements of 10 CFRPart 50, Appendix G in the proposed update. Your description shall include thefollowing:

" Using a proposed composite heatup curve and a proposed cooldown curve asexamples, point out the segments that were limited by closure head, outernozzle, and beltline.

" Confirm availability of material data (initial RTNDT and copper and nickelcontents) for all non-beltline materials for all three unit RPVs and demonstrate that none of them will become limiting under the 54 EFPY fluence.* Confirm that the lowest service temperatures (LSTs) for all Ferritic RCPBcomponents that are not part of the RV have been established for all threeOconee units, and the lowest temperature of 60 *F in the proposed P-T limits arehigher than these LSTs.2.1.2 Response to RAI-12.1.2.1 General Response to RAI-1The 54 EFPY P-T limits for Oconee Units 1, 2, and 3 were developed using themethods described in Topical Report BAW-1 0046A, Revision

24. The P-T limit curveswere developed in accordance with the requirements of 10 CFR 50, Appendix G ,utilizing the analytical methods of Topical Report BAW-10046A Revision 2, and ASME6Code Section X1, Appendix G

Controlled DocumentAREVA NP Inc. ANP-3127Q1NP Revision 1Response to NRC Request for Additional Information Regarding License Amendment Reauest to Update Pressure-Temperature Limit Curves for Oconee Units 1. 2. and 3 Paae 2-3For Babcock & Wilcox nuclear steam supply systems, Topical Report BAW-10046A, Revision 24 describes methods for compliance with the requirements of 10 CFR 50Appendix G, "Fracture Toughness Requirements".

The safety evaluation report (SER)for this report, BAW-10046A, Revision 24 states "BAW 10046, Rev. 2 describes acceptable methods for the development of allowable pressure-temperature limits fornormal operation and for test conditions to assure the prevention of non-ductile fracture.

It may be referenced in future applications..."

The methodology used for B&W plants includes all the ferritic components in theReactor Coolant System. Acceptable methods for the determination of P-T limits for theclosure head, the reactor vessel outlet nozzle, and beltline region are documented.

Asstated in BAW-10046A, Revision 2, "These three regions are the only ones that, atdifferent stages of the vessel's design life, regulate the pressure-temperature limitations of the RC system for normal operation and inservice pressure tests." The P-T limitsdetermined for these components are determined and the resulting composite limitingcurve is then determined utilizing the standard B&W methodology.

Per BAW-10046, Revision 2, "The components for which the lowest service temperature must be definedinclude the RC loop piping and the control rod drive mechanism (the CRDM is anappurtenance to the reactor vessel).

The lowest service temperature of thesecomponents is [ O 0F (based on RTNDT + 100°F) for the piping and [ O 0F forthe CRDM."BAW-1 0046A, Revision 2 addresses all ferritic components of the beltline and non-beltline regions of the RCPB. The NRC has reviewed the methods in this TopicalReport and approved this report by issuance of SER dated April 30, 1986.2.1.2.1.1 Response to Item I of RAI-1One item that was not considered in BAW-1 0046A, Revision 2 was embrittlement fromirradiation damage in the ferritic components adjacent to the components that havebeen traditionally considered as part of the RV beltline.

As plants operate into theperiod of extended operation, these components adjacent to the RV beltline can Controlled DocumentAREVA NP Inc. ANP-3127Q1NP Revision 1Response to NRC Request for Additional Information Regarding License Amendment Reauest to Update Pressure-Temperature Limit Curves for Oconee Units 1. 2. and 3 Page 2-4potentially accumulate fluence to an extent that was not previously considered.

Ofthese components, the RV nozzles may eventually require some further evaluation.

ForOconee Units 1, 2, and 3 at 54 EFPY, the fluence at the lower nozzle belt forging tooutlet nozzle forging weld is less than 1 x 1017 n/cm2 (E>1.0 MeV). Therefore, at 54EFPY the attenuated fluence at the nozzle corner is even lower than this value. Sinceper NUREG-1801, Revision 27, a time-limited aging analysis (TLAA) for neutronirradiation embrittlement is required for materials with a neutron fluence greater than 1 x1017 n/cm2 (E>1.0 MeV), embrittlement in this region does not need to be considered forthe period of extended operation.

Therefore, the original basis document, BAW-10046A, Revision 2 remains applicable for deriving P-T limits for the Oconee Unit 1, 2,and 3 nozzle regions at 54 EFPY.2.1.2.1.2 Response to Item 2 of RAI-1The methodology used to develop Oconee Units 1, 2, and 3 P-T limits at 54 EFPY usedmethodology that considered ferritic materials outside the reactor vessel (RV) beltlineregion having complex geometries that may exhibit higher stresses than those of the RVbeltline shell regions.

Components such as the RV outlet nozzles, the RV closure head,and the reactor coolant piping have reference temperatures (RTNDT'S) that are not ashigh as those for the RV beltline shell materials which have simpler geometries.

Thesenon-beltline components have been evaluated based on lowest service temperatures, as discussed in the response to the third bullet of RAI-1.2.1.2.1.3 Response to First Bullet of RAI-1The Oconee pressure-temperature limits were explicitly developed for the principal segments of the reactor vessel that are known to control reactor coolant systempressure:

the reactor vessel closure head flange, the reactor vessel inlet, outlet, andcore flood nozzles, the nozzle belt (or upper shell) region, the beltline region near thereactor core, the circumferential welds joining the lower and intermediate shell coarses,and the axial seam welds in Unit 1. The governing P-T curve is the collection ofcontrolling pressures considering all segments of the vessel. For the most part, data Controlled DocumentAREVA NP Inc. ANP-3127Q1NP Revision 1Response to NRC Request for Additional Information Regarding License Amendment Reauest to Update Pressure-Temperature Limit Curves for Oconee Units 1. 2. and 3 Paae 2-5from the beltline region is the controlling segment due to the high adjusted reference temperatures of the beltline axial welds, as shown in the heatup and cooldown curvesprovided below for Oconee Unit 1. Only the portion of the heat up curve ranging from[ J to [ ] OF is governed by the closure head flange region (as illustrated inFigure 2.1.2-1),

while the entire cooldown curve of Figure 2.1.2-2 is controlled by thebeltline axial welds. It is noted that the heatup curve between [ I and [ ]OF is forced to be horizontal (flat) to avoid a negative slope when the reactor coolantpump starts at 170 OF.Figure 2.1.2-1 Composite Heatup P-T Curve for Oconee Unit I (Adjusted Figure 7-I of ANP-3127)

Controlled DocumentAREVA NP Inc.Response to NRC Request for Additional Information Regarding License Amendment Reauest to UJndlat PreAsura-Temnehture Limit Curves for Oconee Units 1. 2. and 3ANP-3127Q1NP Revision 1Paae 2-6240012DILV)200016001200800Normal CooldownTemp. Press. -Composite CD Curve(0F) (psig)251 2231246 2221231 1779211 1363191 1083190 1053186 1029181 981171 837166 824161 765155 710146 636135 611110 531105 527100 51370 51365 51260 506I -4000-i 1050100 1SO 200 250300Indicated RCS Inlet Temperature, OFFigure 2.1.2-2 Composite Cooldown P-T Curve for Oconee Unit I (from Figure 7-2of ANP-3127)

Controlled DocumentAREVA NP Inc. ANP-312701 NPRevision 1Response to NRC Request for Additional Information Regarding License Amendment Reauest to Uodate Pressure-Temperature Limit Curves for Oconee Units 1. 2. and 3 Paae 2-72.1.2.1.4 Response to Second Bullet of RAI-1The material data (initial RTNDT and copper and nickel contents) have been obtained forall three Oconee RPV non-beltline materials in the form of the original material CMTRs.Because of the vintage of the CMTRs, they contain limited material data, i.e., only nickelcontents are reported.

Due to the unavailability of measured initial RTNDT values andcopper contents for the Oconee RPV non-beltline materials, the use of generic meanvalues for these specific material properties could be applied.Based on the projected fluence for the Oconee RPV non-beltline materials, components located above the lower nozzle belt forging to upper shell course circumferential weld(not including the lower nozzle belt forging) are projected to receive fluences less than1017 n/cm2 (E > 1 MeV), i.e., these components are predicted to have fluences less than5.2x1 016 n/cm2 (E > 1 MeV). These components are currently below the threshold requiring a TLAA for neutron irradiation embrittlement, 1.0 x 1017 n/cm2, as documented in NUREG-1 801, Revision

2. Therefore for these components, the reference temperatures used as inputs to the development of the P-T curves for the Oconee unitsfollowed the methodology of BAW-10046A, Revision 2.As for the RPV components in the lower portion of the vessel, the predicted 54 EPPYfluences at the lower shell forging to Dutchman forging welds are greater than 1017n/cm2 (E > 1 MeV) for all three Oconee RPVs. Therefore, adjusted reference temperature values for the lower head components (transition ring forging, lower head,and their associated welds) were calculated in accordance with Regulatory Guide 1.99,Revision 28 using the lower shell forging to Dutchman forging weld fluences.

Themaximum adjusted reference temperature is conservatively calculated to be 115 OF(RPV lower head). Based on the predicted 54 EFPY adjusted reference temperatures, the P-T limits for portions of the vessel below the beltline region remain bounded by theclosure head flange region of the vessel.

Controlled DocumentAREVA NP Inc. ANP-3127Q1NP Revision 1Response to NRC Request for Additional Information Regarding License Amendmentto Update Pressure-Temperature Limit Curves for Oconee Units 1. 2. and 3 Paae 2-82.1.2.1.5 Response to Third Bullet of RAI-1Per Article NB-3211, Sub-article (d)(2) of ASME Code Section III9, the lowest servicetemperature (LST) is the minimum fluid temperature retained by the component whenever pressure within the component exceeds 20% of the pre-operational systemhydrostatic test pressure (location corrected values of 553 psig for Oconee 1 and 557psig for Oconee 2 and 3). The ferritic RCPB components that are not part of the reactorvessels at Oconee Units 1, 2, and 3 are the carbon steel reactor coolant piping(minimum LST = [ ] OF) and the martensitic high-alloy chromium Type 403modified steel motor tube (minimum LST = [ ] OF) of the CRDM as reported inBAW-10046, Revision

2. The P-T limits in Figure 2.1.2-1 for Oconee Unit 1 require thatthe reactor coolant temperature reach a temperature of 130 OF before the systempressure can exceed [ ] psig. Although

[ ] OF is less than an RTNDT-based lowest service temperature of [ ] °F for the reactor coolant piping, it has beendemonstrated by Appendix G analysis, as permitted by the alternate provision of ArticleNB-3211 in Sub-article (d)(1), that the allowable pressure in the reactor coolant piping ismuch higher than that of the closure head flange for the entire heatup transient.

Figures7-4 and 7-7 of ANP-3127, Revision 1 show that the system pressure at reactor coolanttemperatures up to [ ] OF is less than the location corrected 20% preservice hydrostatic test pressure of [ ] psig for Oconee Units 2 and 3.2.1.2.2 Conclusion for RAI-1The 54 EFPY P-T limits for Oconee Units 1, 2, and 3 are consistent with therequirements of 10 CFR 50, Appendix G.

Controlled DocumentAREVA NP Inc. ANP-3127Q1NP Revision 1Response to NRC Request for Additional Information Regarding License Amendment Reauest to Uodate Pressure-Temperature Limit Curves for Oconee Units 1. 2. and 3 Paae 2-92.2 RAI-22.2.1 Statement of RAI-2The fluence values at the one-quarter thickness (1/4T) and 3/4T of the RV in Table 3-1of ANP-3127, Revision 1 (the ANP, Enclosure 2 of the February 22, 2013, submittal) appear to be not based on the same RV thickness for the same unit. Please confirmthat you used Equation (3) in Regulatory Guide (RG) 1.99, Revision 2, "Radiation Embrittlement of Reactor Vessel Materials,"

to calculate the fluence at 1/4T and 3/4T ofthe RV. Please also provide the values that you used for "x" in Equation (3) in the ARTcalculations at 1/4T and 3/4T for the limiting materials shown in Table 3-1 and the RVradius that you used in the P-T limit calculations.

Provide the same information forUnits 2 and 3.2.2.2 Response to RAI-2The neutron fluence values at the Y4T and %T vessel wall locations were calculated inaccordance with Equation 3 of Regulatory Guide 1.99, Revision

28. For Oconee Units1, 2 and 3 a minimum wall thickness of 8.44 inches was used for the reactor vesselbeltline regions with a minimum cladding thickness of [ ] inches. The lowernozzle belt forgings vary in thickness from a minimum thickness of 8.44 inches to 12.0inches with a minimum cladding thickness of [ ] inches. These wallthicknesses are depicted in Figure 2.2.2-1 and Figure 2.2.2-2.

Based on the increase inthickness of the lower nozzle belt forgings, the depth into the wall measured from theinner (wetted)

surface, "x", was calculated for the two (2) thicknesses:

8.44 inch Wall Thickness "x" @ %T = [8.44*0.25]

+ [ ] in."x" @ %T = [8.44*0.75]

+ [] in.

Controlled DocumentAREVA NP Inc.ANP-3127Q1NP Revision 1Response to NRC Request for Additional Information Regarding License Amendment Reauest to Update Pressure-Temperature Limit Curves for Oconee Units 1. 2. and 3 Paae 2-1012.0 inch Wall Thickness "x" @ %T = [12.0*0.25]

+ ["x" @ 3/4T = [12.0*0.75]

+ [1 in.1 in.The %T and %T fluence values for the Oconee Units 1, 2 and 3 reactor vessel materials are calculated using these vessel wall depths and the neutron fluence at the innerwetted surface of the vessel; these values are those listed in Tables 3-1, Table 3-2 andTable 3-3 of ANP-3127, Revision 1.The reactor vessel beltline inner radius used in the P-T limit calculations, 85-% inches,is based on the vessel shell inner diameter equal to 171 inches. The nozzle belt innerradius used in the P-T limit calculations is [ ] inches.

Controlled DocumentAREVA NP Inc.Response to NRC Request for Additional Information Regarding License Amendment Reouest to Undate Pressure-Temoerature Limit Curves for Oconee Units 1. 2. and 3ANP-3127Q1NP Revision 1Pnae 2-11Page 2-11Start of 12 in. thickness 8.44 in. thickness

,Outlet Nozzle ForgingWeldLower Nozzle Belt ForgingFigure 2.2.2-1 RPV Configuration for Oconee Unit 1 Controlled DocumentAREVA NP Inc.Response to NRC Request for Additional Information Regarding License Amendment Reauest to Update Pressure-Temoerature Limit Curves for Oconee Units 1. 2. and 3ANP-3127Q1NP Revision 1P~na 2)-12Pqnp 2-12Start of 12 in- thickness 8.44 in. thickness

--Upper Nozzle Belt Forging-Outlet Nozzle ForgingWeld-Lower Nozzle Belt ForgingUpper Shell ForgingLower Shell ForgingLower HeadFigure 2.2.2-2 RPV Configuration for Oconee Units 2 and 3 C~ofltro~ild DocumentAREVA NP Inc. ANP-312701 NPRevision 1Response to NRC Request for Additional Information Regarding License Amendment Reauest to Uodate Pressure-Temoerature Limit Curves for Oconee Units 1. 2. and 3 Page 2-132.3 RAI-32.3.1 Statement of RAI-3Table 3-2 of the ANP indicated that the copper value of the lower nozzle belt to theupper shell circumferential weld of Heat 406L44 for Unit 2 is 0.27% and for the sametype of weld of Heat 821T44 for Unit 3 is 0.24%, both are 0.01% lower than thecorresponding values in the approved license renewal application.

Since theaccumulative effect of several small changes over the years can be significant, pleaseprovide justification for the revision.

2.3.2 Response to RAI-3The copper values for the approved license renewal application were based on best-estimate data available at the time the application was being prepared.

These datawere based on extensive chemical analyses performed on available as deposited weldmetals fabricated with copper-plated filler wires and Linde 80 flux for use in reactorvessel embrittlement assessments.

The sources for these weld metals includedweldments in the form of nozzle belt forging dropouts, reactor vessel beltline regioncutouts, surveillance program test blocks and test specimens, weld qualifications, andre-analysis of original weld qualification chemistry samples.

On May 19-21, 1997 theNRC performed an inspection (Inspection Report No.: 99901300/97-01, dated January28, 1998) at AREVA NP (formally Framatome Technologies, Inc.) to review recordspertaining to the chemical composition of automatic submerged-arc welds in reactorvessels fabricated by Babcock & Wilcox (B&W). During the review process, theinspection identified additional data relevant to the determination of the best-estimate copper and nickel chemical contents for the high-copper Linde 80 weld metals.Based on the additional data identified in the NRC inspection, the best-estimate copperand nickel chemical contents for the high-copper Linde 80 weld metals were updated.The updated best-estimate chemical compositions for the high-copper Linde 80 weldmetals were determined by first establishing a mean value applicable for each particular material source (i.e., nozzle belt dropout, reactor vessel beltline region cutout, Controlled DocumentAREVA NP Inc. ANP-3127Q1NP Revision 1Response to NRC Request for Additional Information Regarding License Amendment Reauest to Uodate Pressure-Temperature Limit Curves for Oconee Units 1. 2. and 3 Paae 2-14surveillance block/specimen, weld qualification, and weld qualification retest).

Thesematerial source means were then used to calculate the mean values for the weld wireheat (e.g., mean-of-the-means).

The updated values based on the above chemical composition re-assessments wereused in the adjusted reference temperature evaluations for the weld metals located inthe Oconee Unit 1, 2 and 3 reactor vessels as reported in Table 3-1, Table 3-2, andTable 3-3 of ANP-3127, Revision 1.2.4 RAI-42.4.1 Statement of RAI-4Section 4.2 of the ANP states that, "A % tNs (tN,- the thickness at the nozzle belt) deepcorner flaw is postulated on the inside surface of the reactor vessel inlet and outletnozzles and core flood nozzle corner."

This suggests that your nozzle methodology ismore complete than that of BAW-1 0046, Revision 2, which performed analysis on outletnozzles only, based on the belief that the outlet nozzle is the most limiting nozzle.Please confirm that actual calculations have been performed on inlet, outlet, and coreflood nozzles to determine the most limiting P-T limits for nozzles in this licenseamendment request (LAR).2.4.2 Response to RAI-4Although not required by BAW-1 0046, allowable pressures were calculated for the inlet,outlet, and core flood nozzles to ensure that the most limiting location was addressed inthe non-beltline region of the vessel.2.5 RAI-52.5.1 Statement of RAI-5Section 4.4 of the ANP states, "The Pressure-Temperature limits derived for the reactorvessel head-to-flange conservatively bounds the minimum required temperature requirements as given in Table 1 of the Appendix G to 10 CFR Part 50." Please use afigure from Figure 7-1 to Figure 7-9 to support and explain this statement.

Controlied DocumentAREVA NP Inc. ANP-3127Q1NP Revision IResponse to NRC Request for Additional Information Regarding License Amendment Reauest to Update Pressure-Temoerature Limit Curves for Oconee Units 1. 2. and 3 Paae 2-152.5.2 Response to RAI-5P-T limits have been derived for the closure flange region of the Oconee reactor vesselhead using stresses for the controlling transient condition (heatup stresses for a flaw onthe outside surface in the crotch region of the vessel head) and the Kic measure offracture toughness.

Based on Oconee specific

analysis, the reactor coolanttemperature must be at least 130 OF for pressures above 20% of the pre-service systemhydrostatic test pressure, which conservatively satisfies the requirement of Item 2.b inTable 1 of Appendix G to 10 CFR Part 50 that the temperature must be at least 120 OFabove the reference temperature of the closure head flange material, which is 0 OF forall three Oconee units. The pressure corrected (location adjusted to the pressuresensor) closure head limits are plotted in Figure 2.5.2-1 along with the requiredtemperature for pressures above 20% of the preservice hydrostatic test pressure.

Figure 2.5.2-1 Location Adjusted Closure Head P-T Limits Controlled DocumentAREVA NP Inc. ANP-3127Q1NP Revision 1Response to NRC Request for Additional Information Regarding License Amendment Reauest to Update Pressure-Temperature Limit Curves for Oconee Units 1. 2. and 3 Paae 2-162.6 RAI-62.6.1 Statement of RAI-6Section 4.6 of the ANP indicated that both ramped and stepped transient definitions aremodeled for normal operation heatup and cooldown.

Please confirm whether thethermal stresses are based on (1) the stepped transient, which is likely to be limiting, or(2) the stepped and the ramped transients depending on time. If Case (2) applies,please provide a discussion of why the stepped transient may not be limiting.

2.6.2 Response to RAI-6Allowable pressures are determined for ramped transients at selected time increments during the transients, considering both the transient response at a selected time pointas well as the steady state response to account for the possibility that the operator canhold a heatup or cooldown event at any point during the transient.

Since it is notexpected that the operator can follow a stepped transient nor can a step change intemperature actually be imposed on the reactor coolant, stepped transients are treatedas a series of hold points, such that the allowable pressures for a stepped transient arecalculated at the end of the step or hold period. Allowable pressures for the steppedtransients, the ramped transients, and the steady state responses are compared andlimiting values are selected to develop the P-T curves. In general, ramped transients control during heatup since the metal temperature at the flaw tip rises slower than itdoes for stepped transients.

During cooldown, steady state conditions control at highertemperatures since steady state conditions are enforced by setting the flaw tiptemperature equal to the fluid temperature at each time point in the transient, whichresults in a zero thermal stress intensity factor (Kit = 0) while lowering the fracturetoughness compared to the transient solution for either ramped or stepped transients.

At lower temperatures, the transient through-wall temperature gradients are more fullydeveloped and the allowable pressure is controlled by the thermal stress intensity factor. Under transient conditions, the ramped transient tends to produce slightly lowerallowable pressures than the stepped transient as the cooldown rate decreases duringthe later stages of the cooldown transient.

Controlled DocumentAREVA NP Inc. ANP-3127Q1NP Revision 1Response to NRC Request for Additional Information Regarding License Amendment Reauest to Uodate Pressure-Temperature Limit Curves for Oconee Units 1. 2. and 3 Paae 2-172.7 RAI-72.7.1 Statement of RAI-7Section 6 of the ANP discussed pressure corrections with the AP listed in Table 6-1.Please confirm whether this AP should be added to or subtracted from the calculated pressure values based on the ASME Code, Section X1, Appendix G methodology.

Likewise, how do you adjust the calculated 1/4T metal temperature to the "indicated reactor coolant system (RCS) inlet temperature?"

2.7.2 Response to RAI-7a) Based on the relative pressure heads between the pressure tap locations and thevessel locations where allowable pressures are calculated, the pressurecorrections listed in Section 6 are subtracted from the calculated allowable pressures to obtain the location adjusted P-T limits.b) Allowable pressures are calculated as a function of the reactor coolant systemfluid temperature (indicated RCS inlet temperature) based on the fracturetoughness corresponding to the metal temperature at the 1/4T flaw depth. Thetransient thermal solution provides the necessary correlation between the fluidtemperature and the 1/4T metal temperature.

2.8 RAI-82.8.1 Statement of RAI-8Figures 7-1 and 7-2 of the ANP illustrate the P-T limits for heatup and cooldown, alongwith pressure temperature pairs of typical points along the P-T limit curves (on the leftside of Figures 7-1 and 7-2). To assist the NRC staff verify the proposed heatup andcooldown curves, please use these pressure temperature pairs as examples andprovide the corresponding thermal stress intensity factors (Kits).

Controlled DocumentAREVA NP Inc. ANP-3127Q1NP Revision 1Response to NRC Request for Additional Information Regarding License Amendment Reauest to Uodate Pressure-Temperature Limit Curves for Oconee Units 1. 2. and 3 Paae 2-182.8.2 Response to RAI-8The Oconee-1 P-T limits for heatup and cooldown provided in Figures 7-1 and 7-2,respectively, of ANP-3127, Revision 1, are the controlling values considering flaworientation (axial or circumferential),

location (beltline, nozzle, or closure head flange),transient type (stepped or ramped),

and initiation temperatures for pump starts/stops and decay heat removal.

Pressure-temperature curves are also typically "smoothed" toeliminate anomalies such as non-monotonically increasing pressures with temperature.

Values of Kit are presented by focusing on the normal heatup results for the rampedtransient with reactor coolant pump start at [ ] OF and normal cooldown results forthe ramped transient with decay heat removal initiation at O J 0F. These twotransients provide most of the data points in Figures 7-1 and 7-2. Figure 2.8.2-1 andFigure 2.8.2-2 below show the "raw" pressure-temperature curves for these twocomponent transients (with pressure corrections for transducer location but withoutsmoothing of discontinuities),

along with the associated Kit thermal stress intensity factors.

The figures also indicate which regions of the curves are controlled by transient or steady state conditions at the 1/4t (1/4t thickness from the inside surface) or 3/4t (1/4tthickness from the outside surface) flaw depths. It is noted that steady state results areobtained by setting Kit equal to zero. Furthermore, Kit is conservatively set equal to zeroat any point during a transient where the thermal stress intensity factor is calculated tobe a negative value. Digital data is also provided in Table 2.8.2-1 and Table 2.8.2-2below.

(Clontrolled DocumentAREVA NP Inc.Response to NRC Request for Additional Information Regarding License Amendment to lind~tA.

PrA I imit for (Thonee Units 1.2_ And 3ANP-3127Q1NP Revision 1pane 2-19Reg"p-rd M Unriate Presqjr-TernneratHre Limit Curves r Oconee Units 1 2 and 3 Pane 2-1 AFigure 2.8.2-1 Corrected P-T Curve for Oconee Unit I Ramped Normal Heatupwith RCP Start at 100°F Controlled DocumentAREVA NP Inc.Response to NRC Request for Additional Information Regarding License Amendment Reauest to Undetp Pressure-Temnerature Limit Curves for Oconee Units 1. 2. and 3ANP-3127Q1NP Revision 1Paae 2-20Figure 2.8.2-2 Corrected P-T Curve for Oconee Unit I Ramped Normal Cooldownwith DHR at 190OF Controlled DocumentAREVA NP Inc.Response to NRC Request for Additional Information Regarding License Amendment Renuast to Undate Pressure-Temnerature Limit Curves for Oconee Units 1 2 and 3ANP-3127Q1NP Revision 1Paae 2-21Table 2.8.2-1 Data Points for Figure 2.8.2-1

'Ccn'trol!ed Do~cumen tAREVA NP Inc,Response to NRC Request for Additional Information Regarding License Amendment Reauest to Undate Pressure-Temoerature Limit Curves for Oconee Units 1. 2 and 3ANP-3127Q1NP Revision 1Paae 2-22Table 2.8.2-2 Data Points for Figure 2.8.2-2 Controlled DocumentAREVA NP Inc. ANP-3127Q1 NPRevision 1Response to NRC Request for Additional Information Regarding License Amendment Reauest to Uodate Pressure-Temperature Limit Curves for Oconee Units 1. 2. and 3 Paae 3-

13.0 REFERENCES

1 ANP-3127, Revision 1, (AREVA Document ID 77-3127-001),

"Oconee NuclearStation Units 1, 2 & 3 Pressure-Temperature Limits at 54 EFPY," January, 20132 Letter, Duke Energy Carolinas, LLC, "Oconee Nuclear Station (ONS), Units 1, 2,and 3, Docket Numbers 50-269, 50-270, and 50-287, License Amendment Request to Update Pressure-Temperature Limit Curves, License Amendment Request (LAR) No. 2012-10,"

NRC ADAMS Accession Number ML13058A059, February 22, 20133 Letter, John P. Boska (NRC) to Mr. Scott Batson (Duke Energy Carolinas),

"Oconee Nuclear Station, Units 1, 2, and 3, Request for Additional Information Regarding Amendment Application Related to Reactor Coolant System Pressureand Temperature Limit Curves (TAC Nos. MF0763, MF0764, and MF0765),"

NRC ADAMS Accession Number ML13165A147, June 21, 20134 AREVA NP Document BAW-10046A, Rev. 2, "Methods of Compliance withFracture Toughness and Operational Requirements of 10CFR50, Appendix G,"June 19865 Code of Federal Regulations, Title 10, Part 50 -Domestic Licensing ofProduction and Utilization Facilities, Appendix G -Fracture Toughness Requirements, Federal Register Vol. 60, No. 243, January 31, 20086 American Society of Mechanical Engineers (ASME) Boiler and Pressure VesselCode, Section Xl, "Rules for Inservice Inspection of Nuclear Power PlantComponents,"

Appendix G, "Fracture Toughness Criteria for Protection AgainstFailure,"

1998 Edition with Addenda through 20007 NUREG-1 801, Revision 2, "Generic Aging Lessons Learned (GALL) Report,"U.S. Nuclear Regulatory Commission, December 20108 U.S. Nuclear Regulatory Commission, Regulatory Guide 1.99, Revision 2,"Radiation Embrittlement of Reactor Vessel Materials,"

May 19889 American Society of Mechanical Engineers (ASME) Boiler and Pressure VesselCode,Section III, "Rules for Construction of Nuclear Facility Components,"

Division 1, Subsection NB, "Class 1 Components,"

1998 Edition with Addendathrough 2000