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{{#Wiki_filter:JLMlA~r" Attachment 2 contains proprietary informationand should be withheld from public disclosure inNuclear Operating Company accordance with 10 CFR 2.390South Tuas Pro/ect Electric Generatin$ Station P.O Bao 289 Wadsworth Texas 77483April 24, 2015NOC-AE-1500325010 CFR 50.55a10 CFR 2.390File No.: D43.01U. S. Nuclear Regulatory CommissionAttention: Document Control DeskWashington, DC 20555-0001South Texas Project Unit 1Docket No. STN 50-498Request for Relief from Code Case N-770-1, Subsection 2400 and Table 1 InspectionFrequency of Reactor Vessel Cold Leg Nozzle to Safe-end Welds with Flaw Analysis(Relief Request RR-ENG-3-17)In accordance with the provisions of 10 CFR 50.55a(a)(3)(ii), STP Nuclear Operating Company(STPNOC) requests relief for South Texas Project (STP) Unit 1 for performing the reactorvessel Cold Leg nozzle to safe-end weld inspections, covered by ASME Code Case N-770-1, bythe currently scheduled outage 1 RE19 (Fall 2015, Unit 1). This relief request proposesextending the inspection period by one operating cycle and performing the Code Case N-770-1inspections in conjunction with the implementation of an approved stress improvement processto mitigate primary water stress corrosion cracking (PWSCC) in the Hot and Cold Leg nozzle tosafe-end welds. The purpose of this relief request is to extend the Code Case N-770-1inspection period by one refueling cycle, approximately 18 months, until Refueling Outage1 RE20 scheduled for Spring 2017.10CFR50.55a(g)(6)(ii)(F)(1), effective July 21, 2011, requires that the STP Inservice Inspection(ISI) program implement ASME Code Case N-770-1, related to examination requirements forClass 1 piping and nozzle dissimilar-metal butt welds. STPNOC has determined thatcompliance with these Code inspection requirements would result in unnecessary hardshipwithout a compensating increase in the level of quality and safety.By performing the Cold Leg weld inspections in conjunction with an approved stressimprovement process during Refueling Outage 1 RE20, STPNOC would reduce unnecessaryradiation exposure to personnel and the need to perform a critical lift of the core barrel.STPNOC requests NRC review and approval of this relief request by September 1, 2015 tosupport the use of the proposed inspection date extension when authorized, as required by 10CFR 50.55a(a)(3).STI: 34114282 NOC-AE-15003250Page 2 of 3This letter contains two attachments. Attachment 1 is non-proprietary; and Attachment 2 is theproprietary version of Attachment 1 and contains proprietary material that should be withheldfrom public disclosure as documented by the affidavits in Enclosure 2.There are no commitments in this letter.If there are any questions, please contact Rafael Gonzales at 361-972-4779, or me at 361-972-7030.Michael BergManager Design EngineeringTesting and Programsrjg
{{#Wiki_filter:JLMlA~r" Attachment 2 contains proprietary information and should be withheld from public disclosure inNuclear Operating Company accordance with 10 CFR 2.390South Tuas Pro/ect Electric Generatin$
Station P.O Bao 289 Wadsworth Texas 77483April 24, 2015NOC-AE-15003250 10 CFR 50.55a10 CFR 2.390File No.: D43.01U. S. Nuclear Regulatory Commission Attention:
Document Control DeskWashington, DC 20555-0001 South Texas Project Unit 1Docket No. STN 50-498Request for Relief from Code Case N-770-1, Subsection 2400 and Table 1 Inspection Frequency of Reactor Vessel Cold Leg Nozzle to Safe-end Welds with Flaw Analysis(Relief Request RR-ENG-3-17)
In accordance with the provisions of 10 CFR 50.55a(a)(3)(ii),
STP Nuclear Operating Company(STPNOC) requests relief for South Texas Project (STP) Unit 1 for performing the reactorvessel Cold Leg nozzle to safe-end weld inspections, covered by ASME Code Case N-770-1, bythe currently scheduled outage 1 RE19 (Fall 2015, Unit 1). This relief request proposesextending the inspection period by one operating cycle and performing the Code Case N-770-1inspections in conjunction with the implementation of an approved stress improvement processto mitigate primary water stress corrosion cracking (PWSCC) in the Hot and Cold Leg nozzle tosafe-end welds. The purpose of this relief request is to extend the Code Case N-770-1inspection period by one refueling cycle, approximately 18 months, until Refueling Outage1 RE20 scheduled for Spring 2017.10CFR50.55a(g)(6)(ii)(F)(1),
effective July 21, 2011, requires that the STP Inservice Inspection (ISI) program implement ASME Code Case N-770-1, related to examination requirements forClass 1 piping and nozzle dissimilar-metal butt welds. STPNOC has determined thatcompliance with these Code inspection requirements would result in unnecessary hardshipwithout a compensating increase in the level of quality and safety.By performing the Cold Leg weld inspections in conjunction with an approved stressimprovement process during Refueling Outage 1 RE20, STPNOC would reduce unnecessary radiation exposure to personnel and the need to perform a critical lift of the core barrel.STPNOC requests NRC review and approval of this relief request by September 1, 2015 tosupport the use of the proposed inspection date extension when authorized, as required by 10CFR 50.55a(a)(3).
STI: 34114282 NOC-AE-15003250 Page 2 of 3This letter contains two attachments.
Attachment 1 is non-proprietary; and Attachment 2 is theproprietary version of Attachment 1 and contains proprietary material that should be withheldfrom public disclosure as documented by the affidavits in Enclosure 2.There are no commitments in this letter.If there are any questions, please contact Rafael Gonzales at 361-972-4779, or me at 361-972-7030.Michael BergManager Design Engineering Testing and Programsrjg


==Enclosures:==
==Enclosures:==
: 1. SOUTH TEXAS PROJECT UNIT 1, Request for Relief from Code Case N-770-1,Subsection 2400 and Table 1 Inspection Frequency of Reactor Vessel Cold Leg Nozzleto Safe-end Welds with Flaw Analysis (Relief Request RR-ENG-3-17)2. Application for Withholding Proprietary Information From Public DisclosureAttachments:1. LTR-PAFM-1 5-27-NP, Technical Justification to Support Extended VolumetricExamination Interval for South Texas Unit 1 Reactor Vessel Inlet Nozzle to Safe EndDissimilar Metal Welds, April 2015 (Non-Proprietary).2. LTR-PAFM-15-27-P, Technical Justification to Support Extended VolumetricExamination Interval for South Texas Unit I Reactor Vessel Inlet Nozzle to Safe EndDissimilar Metal Welds, April 2015 (Proprietary).
: 1. SOUTH TEXAS PROJECT UNIT 1, Request for Relief from Code Case N-770-1,Subsection 2400 and Table 1 Inspection Frequency of Reactor Vessel Cold Leg Nozzleto Safe-end Welds with Flaw Analysis (Relief Request RR-ENG-3-17)
NOC-AE-15003250Page 3 of 3cc:(paper copy)(electronic copy)Regional Administrator, Region IVU.S. Nuclear Regulatory Commission1600 East Lamar BoulevardArlington, TX 76011-4511Lisa M. RegnerSenior Project ManagerU.S. Nuclear Regulatory CommissionOne White Flint North (08H04)11555 Rockville PikeRockville, MD 20852NRC Resident InspectorU. S, Nuclear Regulatory CommissionP. 0. Box 289, Mail Code: MN1 16Wadsworth, TX 77483Morgan, Lewis & Bockius LLPSteve Frantz, EsquireU.S. Nuclear Regulatory CommissionLisa M. RegnerNRG South Texas LPJohn RaganChris O'HaraJim von SuskilCPS EnergyKevin PolioCris EugsterL. D. BlaylockCrain Caton & James, P.C.Peter NemethCity of AustinCheryl MeleJohn WesterTexas Dept. of State Health ServicesRichard A. RatliffRobert Free NOC-AE-15003250Enclosure 1SOUTH TEXAS PROJECT UNIT 1, Request for Relief from Code Case N-770-1, Subsection 2400and Table 1 Inspection Frequency of Reactor Vessel Cold Leg Nozzle to Safe-end Welds with FlawAnalysis (Relief Request RR-ENG-3-17) NOC-AE-15003250Page 1 of 7SOUTH TEXAS PROJECT UNIT 1Request for Relief from Code Case N-770-1, Subsection 2400 and Table 1 Inspection Frequency ofReactor Vessel Cold Leg Nozzle to Safe-end Welds with Flaw Analysis(Relief Request RR-ENG-3-17)A. ASME Corn ponent(s) AffectedThe affected components are STP Unit 1 reactor vessel Cold Leg nozzle to safe-end welds(Table 1), which are Alloy 600 welds subject to Code Case N-770-1 (Reference 1).Table 1 -STP Unit 1reactor vessel Cold Lea nozzle to safe-end weldsUNIT 1CATEGORY ITEMNO STP COMP ID COMPDESCSUMMARYNON-770-1 B 101350 RPV1-N2ASE SAFE END TORPV LOOP AINLET NOZZLEN-770-1 B 101485 RPV1-N2BSE SAFE END TORPV LOOP BINLET NOZZLEN-770-1 B 101635 RPV1-N2CSE SAFE END TORPV LOOP CINLET NOZZLEN-770-1 B 101775 RPV1-N2DSE SAFE END TORPV LOOP DINLET NOZZLEB. Applicable ASME Code Edition and AddendaASME Section Xl 2004 Edition (Reference 2)Code Case N-770-1 as referenced in 10CFR50.55a(g)(6)(ii)(F)(1).C. Applicable ASME Code RequirementTable 1 of Code Case N-770-1 requires volumetric examination of essentially 100% of InspectionItem B pressure retaining welds once every second inspection period, not to exceed 7 years.This is the third In-service Inspection (ISI)interval beginning September 25, 2010 throughSeptember 24, 2020.D. Reason for Relief from Code RequirementsSTPNOC is requesting a relief to extend the Cold Leg weld inspections one cycle(approximately 18 months) to Spring 2017 during Refueling Outage 1 RE20. During1 RE20, STPNOC will be performing mitigation of primary water stress corrosion cracking(PWSCC) in the Cold Leg nozzle to safe-end welds using a stress improvement processwhich requires the performance of a critical core barrel lift. If relief is granted for the ColdLeg weld inspection extension, STP can perform the inspections and the mitigation ofPWSCC during the same evolution, reducing the risk for performing two separate criticallifts and adhering to best "As Low As Reasonably Achievable" (ALARA) practices. NOC-AE-15003250Page 2 of 7E. Proposed Alternative and Basis for Use:10CFR50.55a(a)(3) states in part:Any proposed alternatives must be submitted and authorized prior to implementation. The applicantor licensee shall demonstrate that:(i) the proposed alternatives would provide an acceptable level of quality and safety, or(ii) compliance with the specified requirements of this section would result in hardship or unusualdifficulty without a compensating increase in the level of quality and safety.STPNOC believes that the proposed alternative inspection schedule presented in this requestprovides an acceptable level of quality and safety. STPNOC proposes a one-time extension toCode Case N-770-1, Table 1, Inspection Item B, volumetric examinations from a period not toexceed 7 years to a one time period not to exceed 8 years for STP Unit 1.During the Unit 1 Spring 2017 refueling outage, STPNOC will perform the mitigation of PWSCC onthe reactor vessel inlet and outlet nozzle to safe end Alloy 82/182 dissimilar metal (DM) welds.STPNOC plans to use a non-welded stress improvement method (meeting the performance criteriaof Code Case N-770-1 Appendix 1) as the mitigation process to minimize the potential of PWSCC bypermanently eliminating the tensile stress through approximately 50% of the inner DM weld wallthickness.Examination of Code Case N-770-1 Item B (Cold Leg) welds are performed from the InsideDiameter (ID) in Unit 1 due to limited access from the outside surface of the pipe. The inspection ofItem B (Cold Leg) welds from the ID requires removal of the reactor vessel core barrel.Removing the reactor vessel lower internals assembly (core barrel) is considered to be a critical liftdue to the weight of the component, the tight clearances involved, and the radiation emitted by theassembly. For these reasons, only personnel directly involved with the movement of the internalsare typically allowed in containment during the evolution. Remote cameras are utilized to allow mostpersonnel involved with the lift to be outside of the refueling cavity area to minimize personnelradiation exposure. The lower internals lifts are performed solely by viewing cameras. If the needarises the Polar Crane operator is instructed to sit on the floor of the cab or behind shielding and notto raise his head above the cab area of the crane to maintain his radiation dose as low asreasonably achievable (ALARA). NOC-AE-15003250Page 3 of 7For STP, removing the core barrel requires that it be raised above the refueling cavity water levelduring transfer from the reactor vessel to the storage stand location. The radiation exposure levelsfor this activity can be high and necessitate evacuation of personnel from containment andinstallation of shielding for the polar crane operator(s). In addition, the dose rates in the area wouldincrease due to the presence of the reactor vessel in the temporary storage location. Aligning the N-770-1 inspection with the non-welded stress improvement method activity would reduceunnecessary radiation exposure to personnel. Eliminating the need to remove the core barrel andlower internals during 1 RE19 could save approximately 610.5 mrem of dose.The total dose attributed to removal of the core barrel and lower internals was estimated based ondata from 2RE 14, the most recent outage when the core barrel was removed. The total dose for theactual work activities to remove and install the reactor core barrel and lower internals during 2RE14was 123 mrem. The core barrel was transferred to the Lower Internal Storage Area (LISA) where itwas stored underwater for 13 days. The dose rates in the vicinity of the LISA with the core barrelpresent were compared to the dose rates without the core barrel present, and the approximateincrease in dose rates in the general area walkway was 1.3 mrem per hour. Dose rates weremeasured on the South end of the 68' elevation of the Reactor Containment Building (RCB), whichis a general area walkway and a common travel path for workers inside containment. During the 13days that the core barrel was stored in the LISA, workers could have received additional dose ofapproximately 487.5 mrem1 (see assumptions below). Therefore, the total dose associated withmoving and storing the core barrel and lower internals is 610.5 mrem.Assumptions1. The total time the core barrel remained in the LISA, and thus, caused increase dose rates inthe general area walkway was 13 days.2. The total RWP-hours during those 13 days was approximately 37,500 hours.3. The total number of hours that workers may have spent in the vicinity of the 68' with higherdose rates is approximately 1% of the total RWP-hours = 375 hours.4. The average increase in dose rates in the general area walkway was 1.3 mrem/hour.Calculation: 375 hours x 1.3 = 487.5 mremOperating experience on Primary Water Stress Corrosion Cracking (PWSCC) of Alloy 82/182 weldsshows that weld repairs performed during original plant construction are a significant contributor inthe initiation and propagation of cracking. A review of the construction records and a weld repairsearch performed for the STP Unit 1 Reactor Vessel nozzle Alloy 82/182 welds did not identify anyweld repairs performed on these welds during original plant construction. NOC-AE-15003250Page 4 of 7During the Fall 2009 Unit 1 refueling outage, a volumetric examination was performed to thespecifications of ASME Xl Appendix VIII along with a supplemental eddy current test. In April 2014,ultrasonic (volumetric) and eddy current (surface) exams were performed on the STP Unit 1 Hot Legwelds and no indications were identified. In fall 2015, ultrasonic (volumetric) and eddy current(surface) exams are scheduled to be performed on the STP Unit 1Cold Leg welds to meet therequirement of N-770-1. The absence of any indications in the Hot Leg welds in 2014 providesadded assurance that the one time extension of the inspection of the Cold Leg welds byapproximately 18 months provides an acceptable level of quality and safety.STP will perform non-welded stress improvement method on the reactor vessel inlet and outletnozzle to safe end welds during the 1RE20 refueling outage scheduled for spring 2017. Thisproposed approach reduces radiological exposure and personnel safety hazards associated withcritical lifting of the reactor vessel lower internals assembly (core barrel). Therefore, deferral of theCold Leg Nozzle inspections for STP Unit 1 refueling outage would eliminate the increased radiationexposure associated with the removal of the core barrel.Technical BasisElectric Power Research Institute (EPRI) Technical Report for Materials Reliability Program: PWRReactor Coolant System Cold-Loop Dissimilar Metal Butt Weld Reexamination Interval Extension,MRP-349 (Reference 3) provides the basis for extension of the current volumetric inspection intervalfor the Reactor Pressure Vessel (RPV) Cold Leg DM welds from every second inspection period or 7years, as currently required by Code Case N-770-1, to 8 years in the current inspection interval. Insummary, the basis for one time extension of Code Case N-770-1, Table 1, Inspection Item B,volumetric examinations is: (1) there has been no service experience with cracking found in RPVCold Leg DM welds, (2) crack growth rates in RPV Cold Leg DM welds are small, and (3) likelihoodof cracking or through wall leaks is very small in RPV Cold Leg DM welds. This technical basisdemonstrates that the re-examination interval can be extended to 8 years while maintaining anacceptable level of quality and safety.In addition, a site specific flaw tolerance analysis has been performed to determine the largest initialaxial and circumferential flaws that could be left behind in service and remain acceptable betweenthe planned examinations (Reference 4). This maximum allowable flaw size could then becompared to any flaw size detected during inlet nozzle DM weld examinations. The attachment(Attachment 1 Non-proprietary and Attachment 2 Proprietary) to this enclosure contains the flawtolerance analysis in Reference 4.Service ExperienceThe STP Unit 1 Cold Leg welds were last examined in Fall 2009 using remote mechanizedexaminations from the ID. The examinations were performed in accordance with Appendix VIII usingperformance demonstrated methods where 100% of the flaws in the test specimens were detected.In addition, an eddy current examination was performed on the inside (or wetted) surface to inspectfor surface connected flaws. No recordable indications were identified during the 2009examinations. Additionally, all volumetric examinations of the STP Unit 1 Cold Leg welds prior to2009 did not identify any indications requiring resolution. The technique used in site specific examsincluded 100% coverage for axial and circumferential flaws. In these exams, data is obtained usingencoded techniques allowing the data to be reviewed by multiple qualified examiners. Site specificmock-ups were not used because of the flat, uniform surface associated with performance of theseexaminations from the ID. These techniques provide strong assurance that flaws will be detected NOC-AE-15003250Page 5 of 7during inspections. Each STP Unit 1 Cold Leg is exposed to approximately 5630F (Cold LegTemperature) during normal plant operation.Crack Growth Rates (Flaw Tolerance)All of the flaw tolerance analyses performed to date have shown that the critical crack sizes in large-diameter butt welds operating at Cold Leg temperatures are very large. Assuming that a flaw isinitiated, the time required for the flaw to grow to through-wall is in excess of 20 years in most casesanalyzed. The time to grow from a through-wall leak to a crack equal to the critical crack size can bein excess of 40 years.More recent analyses have been performed for the RPV nozzles using through-wall residual stressdistributions that were developed based on the most recent guidance (Reference 3). These analyseshave shown that the flaw tolerance of these locations is high and postulated circumferential flaws willnot reach the maximum ASME allowable depth in less than 10 years. Crack growth analysis isgiven for limiting plants part-circumferential through-wall flaws in Table 5-2 of MRP-349.Probability of Crackinq or Through Wall LeaksAnalyses have been performed to calculate the probability of failure for Alloy 82/182 welds usingboth probabilistic fracture mechanics and statistical methods. Both approaches have shown that thelikelihood of cracking or through-wall leaks in large-diameter Cold Led welds is very small.Furthermore, sensitivity studies performed using probabilistic fracture mechanics have shown thateven for the more limiting high temperature locations, more frequent inspections than required bySection Xl, such as that in MRP-139 (Reference 5) or Code Case N-770-1, have only a small benefitin terms of risk.Though past service experience may not be an absolute indicator of the likelihood of future cracking,the experience provides an indication of the relative likelihood of cracking in Cold Leg temperaturelocations versus Hot Leg temperature locations. While there is a significant amount of PWSCCservice experience in Hot Leg locations, the number of indications in large-bore butt welds is stillsmall relative to the number of potential locations. Also, all indications have been detected beforethey were a safety concern. Therefore, if Hot Leg PWSCC is a leading indicator for Cold LegPWSCC and the higher frequency of inspections will be maintained for the Hot Leg locations, it isreasonable to conclude that a moderately less rigorous inspection schedule would be capable ofdetecting any Cold Leg indications before they became large enough to be a significant concern. NOC-AE-15003250Page 6 of 7Table 2 below provides a summary of the latest Nozzle to Safe-End Welds inspection for STP Unit 1(1 RE18) and evaluation of the recorded indications. This information confirms that satisfactoryexaminations have been performed on the STP Unit 1 Dissimilar Metal Welds.Table 2: Information Pertaining to Class 1 Piping and Nozzle Dissimilar-Metal Butt WeldsInspection -STP Unit 1Inspection During the most recent inservice inspection, all Code Case N-770-1Methodology: Inspection Item A-2 (Hot Leg) welds, were governed by the ASME SectionXl, 2004 Edition, with no Addenda, Code Case N-770-1 as incorporated byreference 10CFR50.55a.Number of past Cold Leg examinations were performed with 10-Year inservice inspectionsinspections: 1RE08 (1999) and 1RE15 (2009).Number of There were no recordable indications identified during the most recentindications found: inservice inspection.Proposed The third inservice inspection is currently scheduled to be performed ininspection 2015 and 2020. Pending approval of this relief request, the Unit 1 inspectionschedule for would be (Baseline Examination after Mitigation) 2017 and 2027.balanceof plant life:F. Duration of Prooosed AlternativeThis request is applicable to STPNOC's ISI program for the third interval for STP Unit 1 and is not toexceed 18 months to Spring 2017 for Refueling Outage 1 RE20. NOC-AE-15003250Page 7 of 7G. References1. Code Case N-770-1, Alternative Examination Requirements and Acceptance Standards forClass 1 PWR Piping and Vessel Nozzle Butt Welds Fabricated with UNS N06082 or UNSW86182 Weld Filler Material With or Without Application of listed Mitigation Activities SectionXI, Division 1.2. ASME Boiler and Pressure Vessel Code, Section XI, 2004 Edition No Addenda, AmericanSociety of Mechanical Engineers, New York.3. EPRI, Materials Reliability Program: PWR Reactor Coolant System Cold-Loop DissimilarMetal Butt Weld Reexamination Interval Extension (MRP-349), August 2012, (1025852).4. Technical Justification to Support Extended Volumetric Examination Interval for South TexasUnit 1 Reactor Vessel Inlet Nozzle to Safe End Dissimilar Metal Welds, LTR-PAFM-15-27-P,Westinghouse, April 2015.5. Material Reliability Program: Primary System Piping Butt Weld Inspection and EvaluationGuideline (MRP-139, Revision 1), December 2008, (1015009).H. PrecedentsRelief from this examination requirement to apply the proposed alternative at the South TexasProject was previously approved by the NRC for the following (with ADAMS Accession No.references):(1) Indian Point Nuclear Generating Unit No. 2 -Request for Relief Request No. IP2-lSI-RR-14,Code Case N-770-1, Reactor Coolant System Cold Leg Nozzle Weld Inspection FrequencyExtention (TAC No. ME6801), dated February 2, 2012 (ML120260090).(2) Arkansas Nuclear One, Unit No. 1 -Request for Alternative ANO1-ISI-023 to ASME CodeCase N-770-1 Volumetric Examination Frequency Requirements for the Fourth 10-YearInservice Inspection Interval (TAC No. MF3176), dated October 29, 2014 (ML14282A479).(3) Joseph M. Farley Nuclear Plant, Units 1 and 2 -Request for Alternative FNP-ISI-13Regarding Deferral of Inservice Inspection of Reactor Pressure Vessel Cold Leg NozzleDissimilar Metal Welds (TAC Nos. ME9739 and ME 9740), dated August 8, 2013(ML13212A176).Attachments(1) LTR-PAFM-15-27-NP, Technical Justification to Support Extended Volumetric ExaminationInterval for South Texas Unit 1 Reactor Vessel Inlet Nozzle to Safe End Dissimilar MetalWelds, April 2015 (Non-Proprietary).(2) LTR-PAFM-15-27-P, Technical Justification to Support Extended Volumetric ExaminationInterval for South Texas Unit 1 Reactor Vessel Inlet Nozzle to Safe End Dissimilar MetalWelds, April 2015 (Proprietary). NOC-AE-15003250Enclosure 2Application for Withholding Proprietary Information From Public Disclosure Westinghouse Electric CompanyW estinghouse Engineering, Equipment and Major Projects1000 Wesninghouse Drive, Building 3Cranberry Township, Pennsylvania 16066USAU.S. Nuclear Regulatory Commission Direct tel: (412) 374-4643Document Control Desk Direct fax: (724) 940-856011555 Rockville Pike e-mail: greshaja@westinghouse.comRockville, MD 20852 Proj letter: ST-WN-NOC-15-14CAW-15-4167April 22, 2015APPLICATION FOR WITHHOLDING PROPRIETARYINFORMATION FROM PUBLIC DISCLOSURE
: 2. Application for Withholding Proprietary Information From Public Disclosure Attachments:
: 1. LTR-PAFM-1 5-27-NP, Technical Justification to Support Extended Volumetric Examination Interval for South Texas Unit 1 Reactor Vessel Inlet Nozzle to Safe EndDissimilar Metal Welds, April 2015 (Non-Proprietary).
: 2. LTR-PAFM-15-27-P, Technical Justification to Support Extended Volumetric Examination Interval for South Texas Unit I Reactor Vessel Inlet Nozzle to Safe EndDissimilar Metal Welds, April 2015 (Proprietary).
NOC-AE-15003250 Page 3 of 3cc:(paper copy)(electronic copy)Regional Administrator, Region IVU.S. Nuclear Regulatory Commission 1600 East Lamar Boulevard Arlington, TX 76011-4511 Lisa M. RegnerSenior Project ManagerU.S. Nuclear Regulatory Commission One White Flint North (08H04)11555 Rockville PikeRockville, MD 20852NRC Resident Inspector U. S, Nuclear Regulatory Commission P. 0. Box 289, Mail Code: MN1 16Wadsworth, TX 77483Morgan, Lewis & Bockius LLPSteve Frantz, EsquireU.S. Nuclear Regulatory Commission Lisa M. RegnerNRG South Texas LPJohn RaganChris O'HaraJim von SuskilCPS EnergyKevin PolioCris EugsterL. D. BlaylockCrain Caton & James, P.C.Peter NemethCity of AustinCheryl MeleJohn WesterTexas Dept. of State Health ServicesRichard A. RatliffRobert Free Enclosure 1NOC-AE-15003250 Enclosure 1SOUTH TEXAS PROJECT UNIT 1, Request for Relief from Code Case N-770-1, Subsection 2400and Table 1 Inspection Frequency of Reactor Vessel Cold Leg Nozzle to Safe-end Welds with FlawAnalysis (Relief Request RR-ENG-3-17)
Enclosure 1NOC-AE-15003250 Page 1 of 7SOUTH TEXAS PROJECT UNIT 1Request for Relief from Code Case N-770-1, Subsection 2400 and Table 1 Inspection Frequency ofReactor Vessel Cold Leg Nozzle to Safe-end Welds with Flaw Analysis(Relief Request RR-ENG-3-17)
A. ASME Corn ponent(s)
AffectedThe affected components are STP Unit 1 reactor vessel Cold Leg nozzle to safe-end welds(Table 1), which are Alloy 600 welds subject to Code Case N-770-1 (Reference 1).Table 1 -STP Unit 1reactor vessel Cold Lea nozzle to safe-end weldsUNIT 1CATEGORY ITEMNO STP COMP ID COMPDESCSUMMARYNO N-770-1 B 101350 RPV1-N2ASE SAFE END TORPV LOOP AINLET NOZZLEN-770-1 B 101485 RPV1-N2BSE SAFE END TORPV LOOP BINLET NOZZLEN-770-1 B 101635 RPV1-N2CSE SAFE END TORPV LOOP CINLET NOZZLEN-770-1 B 101775 RPV1-N2DSE SAFE END TORPV LOOP DINLET NOZZLEB. Applicable ASME Code Edition and AddendaASME Section Xl 2004 Edition (Reference 2)Code Case N-770-1 as referenced in 10CFR50.55a(g)(6)(ii)(F)(1).
C. Applicable ASME Code Requirement Table 1 of Code Case N-770-1 requires volumetric examination of essentially 100% of Inspection Item B pressure retaining welds once every second inspection period, not to exceed 7 years.This is the third In-service Inspection (ISI)interval beginning September 25, 2010 throughSeptember 24, 2020.D. Reason for Relief from Code Requirements STPNOC is requesting a relief to extend the Cold Leg weld inspections one cycle(approximately 18 months) to Spring 2017 during Refueling Outage 1 RE20. During1 RE20, STPNOC will be performing mitigation of primary water stress corrosion cracking(PWSCC) in the Cold Leg nozzle to safe-end welds using a stress improvement processwhich requires the performance of a critical core barrel lift. If relief is granted for the ColdLeg weld inspection extension, STP can perform the inspections and the mitigation ofPWSCC during the same evolution, reducing the risk for performing two separate criticallifts and adhering to best "As Low As Reasonably Achievable" (ALARA) practices.
Enclosure 1NOC-AE-15003250 Page 2 of 7E. Proposed Alternative and Basis for Use:10CFR50.55a(a)(3) states in part:Any proposed alternatives must be submitted and authorized prior to implementation.
The applicant or licensee shall demonstrate that:(i) the proposed alternatives would provide an acceptable level of quality and safety, or(ii) compliance with the specified requirements of this section would result in hardship or unusualdifficulty without a compensating increase in the level of quality and safety.STPNOC believes that the proposed alternative inspection schedule presented in this requestprovides an acceptable level of quality and safety. STPNOC proposes a one-time extension toCode Case N-770-1, Table 1, Inspection Item B, volumetric examinations from a period not toexceed 7 years to a one time period not to exceed 8 years for STP Unit 1.During the Unit 1 Spring 2017 refueling outage, STPNOC will perform the mitigation of PWSCC onthe reactor vessel inlet and outlet nozzle to safe end Alloy 82/182 dissimilar metal (DM) welds.STPNOC plans to use a non-welded stress improvement method (meeting the performance criteriaof Code Case N-770-1 Appendix  
: 1) as the mitigation process to minimize the potential of PWSCC bypermanently eliminating the tensile stress through approximately 50% of the inner DM weld wallthickness.
Examination of Code Case N-770-1 Item B (Cold Leg) welds are performed from the InsideDiameter (ID) in Unit 1 due to limited access from the outside surface of the pipe. The inspection ofItem B (Cold Leg) welds from the ID requires removal of the reactor vessel core barrel.Removing the reactor vessel lower internals assembly (core barrel) is considered to be a critical liftdue to the weight of the component, the tight clearances  
: involved, and the radiation emitted by theassembly.
For these reasons, only personnel directly involved with the movement of the internals are typically allowed in containment during the evolution.
Remote cameras are utilized to allow mostpersonnel involved with the lift to be outside of the refueling cavity area to minimize personnel radiation exposure.
The lower internals lifts are performed solely by viewing cameras.
If the needarises the Polar Crane operator is instructed to sit on the floor of the cab or behind shielding and notto raise his head above the cab area of the crane to maintain his radiation dose as low asreasonably achievable (ALARA).
Enclosure 1NOC-AE-15003250 Page 3 of 7For STP, removing the core barrel requires that it be raised above the refueling cavity water levelduring transfer from the reactor vessel to the storage stand location.
The radiation exposure levelsfor this activity can be high and necessitate evacuation of personnel from containment andinstallation of shielding for the polar crane operator(s).
In addition, the dose rates in the area wouldincrease due to the presence of the reactor vessel in the temporary storage location.
Aligning the N-770-1 inspection with the non-welded stress improvement method activity would reduceunnecessary radiation exposure to personnel.
Eliminating the need to remove the core barrel andlower internals during 1 RE19 could save approximately 610.5 mrem of dose.The total dose attributed to removal of the core barrel and lower internals was estimated based ondata from 2RE 14, the most recent outage when the core barrel was removed.
The total dose for theactual work activities to remove and install the reactor core barrel and lower internals during 2RE14was 123 mrem. The core barrel was transferred to the Lower Internal Storage Area (LISA) where itwas stored underwater for 13 days. The dose rates in the vicinity of the LISA with the core barrelpresent were compared to the dose rates without the core barrel present, and the approximate increase in dose rates in the general area walkway was 1.3 mrem per hour. Dose rates weremeasured on the South end of the 68' elevation of the Reactor Containment Building (RCB), whichis a general area walkway and a common travel path for workers inside containment.
During the 13days that the core barrel was stored in the LISA, workers could have received additional dose ofapproximately 487.5 mrem1 (see assumptions below). Therefore, the total dose associated withmoving and storing the core barrel and lower internals is 610.5 mrem.Assumptions
: 1. The total time the core barrel remained in the LISA, and thus, caused increase dose rates inthe general area walkway was 13 days.2. The total RWP-hours during those 13 days was approximately 37,500 hours.3. The total number of hours that workers may have spent in the vicinity of the 68' with higherdose rates is approximately 1% of the total RWP-hours  
= 375 hours.4. The average increase in dose rates in the general area walkway was 1.3 mrem/hour.
Calculation:
375 hours x 1.3 = 487.5 mremOperating experience on Primary Water Stress Corrosion Cracking (PWSCC) of Alloy 82/182 weldsshows that weld repairs performed during original plant construction are a significant contributor inthe initiation and propagation of cracking.
A review of the construction records and a weld repairsearch performed for the STP Unit 1 Reactor Vessel nozzle Alloy 82/182 welds did not identify anyweld repairs performed on these welds during original plant construction.
Enclosure 1NOC-AE-15003250 Page 4 of 7During the Fall 2009 Unit 1 refueling outage, a volumetric examination was performed to thespecifications of ASME Xl Appendix VIII along with a supplemental eddy current test. In April 2014,ultrasonic (volumetric) and eddy current (surface) exams were performed on the STP Unit 1 Hot Legwelds and no indications were identified.
In fall 2015, ultrasonic (volumetric) and eddy current(surface) exams are scheduled to be performed on the STP Unit 1Cold Leg welds to meet therequirement of N-770-1.
The absence of any indications in the Hot Leg welds in 2014 providesadded assurance that the one time extension of the inspection of the Cold Leg welds byapproximately 18 months provides an acceptable level of quality and safety.STP will perform non-welded stress improvement method on the reactor vessel inlet and outletnozzle to safe end welds during the 1RE20 refueling outage scheduled for spring 2017. Thisproposed approach reduces radiological exposure and personnel safety hazards associated withcritical lifting of the reactor vessel lower internals assembly (core barrel).
Therefore, deferral of theCold Leg Nozzle inspections for STP Unit 1 refueling outage would eliminate the increased radiation exposure associated with the removal of the core barrel.Technical BasisElectric Power Research Institute (EPRI) Technical Report for Materials Reliability Program:
PWRReactor Coolant System Cold-Loop Dissimilar Metal Butt Weld Reexamination Interval Extension, MRP-349 (Reference  
: 3) provides the basis for extension of the current volumetric inspection intervalfor the Reactor Pressure Vessel (RPV) Cold Leg DM welds from every second inspection period or 7years, as currently required by Code Case N-770-1, to 8 years in the current inspection interval.
Insummary, the basis for one time extension of Code Case N-770-1, Table 1, Inspection Item B,volumetric examinations is: (1) there has been no service experience with cracking found in RPVCold Leg DM welds, (2) crack growth rates in RPV Cold Leg DM welds are small, and (3) likelihood of cracking or through wall leaks is very small in RPV Cold Leg DM welds. This technical basisdemonstrates that the re-examination interval can be extended to 8 years while maintaining anacceptable level of quality and safety.In addition, a site specific flaw tolerance analysis has been performed to determine the largest initialaxial and circumferential flaws that could be left behind in service and remain acceptable betweenthe planned examinations (Reference 4). This maximum allowable flaw size could then becompared to any flaw size detected during inlet nozzle DM weld examinations.
The attachment (Attachment 1 Non-proprietary and Attachment 2 Proprietary) to this enclosure contains the flawtolerance analysis in Reference 4.Service Experience The STP Unit 1 Cold Leg welds were last examined in Fall 2009 using remote mechanized examinations from the ID. The examinations were performed in accordance with Appendix VIII usingperformance demonstrated methods where 100% of the flaws in the test specimens were detected.
In addition, an eddy current examination was performed on the inside (or wetted) surface to inspectfor surface connected flaws. No recordable indications were identified during the 2009examinations.
Additionally, all volumetric examinations of the STP Unit 1 Cold Leg welds prior to2009 did not identify any indications requiring resolution.
The technique used in site specific examsincluded 100% coverage for axial and circumferential flaws. In these exams, data is obtained usingencoded techniques allowing the data to be reviewed by multiple qualified examiners.
Site specificmock-ups were not used because of the flat, uniform surface associated with performance of theseexaminations from the ID. These techniques provide strong assurance that flaws will be detected Enclosure 1NOC-AE-15003250 Page 5 of 7during inspections.
Each STP Unit 1 Cold Leg is exposed to approximately 5630F (Cold LegTemperature) during normal plant operation.
Crack Growth Rates (Flaw Tolerance)
All of the flaw tolerance analyses performed to date have shown that the critical crack sizes in large-diameter butt welds operating at Cold Leg temperatures are very large. Assuming that a flaw isinitiated, the time required for the flaw to grow to through-wall is in excess of 20 years in most casesanalyzed.
The time to grow from a through-wall leak to a crack equal to the critical crack size can bein excess of 40 years.More recent analyses have been performed for the RPV nozzles using through-wall residual stressdistributions that were developed based on the most recent guidance (Reference 3). These analyseshave shown that the flaw tolerance of these locations is high and postulated circumferential flaws willnot reach the maximum ASME allowable depth in less than 10 years. Crack growth analysis isgiven for limiting plants part-circumferential through-wall flaws in Table 5-2 of MRP-349.Probability of Crackinq or Through Wall LeaksAnalyses have been performed to calculate the probability of failure for Alloy 82/182 welds usingboth probabilistic fracture mechanics and statistical methods.
Both approaches have shown that thelikelihood of cracking or through-wall leaks in large-diameter Cold Led welds is very small.Furthermore, sensitivity studies performed using probabilistic fracture mechanics have shown thateven for the more limiting high temperature locations, more frequent inspections than required bySection Xl, such as that in MRP-139 (Reference  
: 5) or Code Case N-770-1, have only a small benefitin terms of risk.Though past service experience may not be an absolute indicator of the likelihood of future cracking, the experience provides an indication of the relative likelihood of cracking in Cold Leg temperature locations versus Hot Leg temperature locations.
While there is a significant amount of PWSCCservice experience in Hot Leg locations, the number of indications in large-bore butt welds is stillsmall relative to the number of potential locations.
Also, all indications have been detected beforethey were a safety concern.
Therefore, if Hot Leg PWSCC is a leading indicator for Cold LegPWSCC and the higher frequency of inspections will be maintained for the Hot Leg locations, it isreasonable to conclude that a moderately less rigorous inspection schedule would be capable ofdetecting any Cold Leg indications before they became large enough to be a significant concern.
Enclosure 1NOC-AE-15003250 Page 6 of 7Table 2 below provides a summary of the latest Nozzle to Safe-End Welds inspection for STP Unit 1(1 RE18) and evaluation of the recorded indications.
This information confirms that satisfactory examinations have been performed on the STP Unit 1 Dissimilar Metal Welds.Table 2: Information Pertaining to Class 1 Piping and Nozzle Dissimilar-Metal Butt WeldsInspection  
-STP Unit 1Inspection During the most recent inservice inspection, all Code Case N-770-1Methodology:
Inspection Item A-2 (Hot Leg) welds, were governed by the ASME SectionXl, 2004 Edition, with no Addenda, Code Case N-770-1 as incorporated byreference 10CFR50.55a.
Number of past Cold Leg examinations were performed with 10-Year inservice inspections inspections:
1RE08 (1999) and 1RE15 (2009).Number of There were no recordable indications identified during the most recentindications found: inservice inspection.
Proposed The third inservice inspection is currently scheduled to be performed ininspection 2015 and 2020. Pending approval of this relief request, the Unit 1 inspection schedule for would be (Baseline Examination after Mitigation) 2017 and 2027.balanceof plant life:F. Duration of Prooosed Alternative This request is applicable to STPNOC's ISI program for the third interval for STP Unit 1 and is not toexceed 18 months to Spring 2017 for Refueling Outage 1 RE20.
Enclosure 1NOC-AE-15003250 Page 7 of 7G. References
: 1. Code Case N-770-1, Alternative Examination Requirements and Acceptance Standards forClass 1 PWR Piping and Vessel Nozzle Butt Welds Fabricated with UNS N06082 or UNSW86182 Weld Filler Material With or Without Application of listed Mitigation Activities SectionXI, Division 1.2. ASME Boiler and Pressure Vessel Code, Section XI, 2004 Edition No Addenda, AmericanSociety of Mechanical Engineers, New York.3. EPRI, Materials Reliability Program:
PWR Reactor Coolant System Cold-Loop Dissimilar Metal Butt Weld Reexamination Interval Extension (MRP-349),
August 2012, (1025852).
: 4. Technical Justification to Support Extended Volumetric Examination Interval for South TexasUnit 1 Reactor Vessel Inlet Nozzle to Safe End Dissimilar Metal Welds, LTR-PAFM-15-27-P, Westinghouse, April 2015.5. Material Reliability Program:
Primary System Piping Butt Weld Inspection and Evaluation Guideline (MRP-139, Revision 1), December 2008, (1015009).
H. Precedents Relief from this examination requirement to apply the proposed alternative at the South TexasProject was previously approved by the NRC for the following (with ADAMS Accession No.references):
(1) Indian Point Nuclear Generating Unit No. 2 -Request for Relief Request No. IP2-lSI-RR-14, Code Case N-770-1, Reactor Coolant System Cold Leg Nozzle Weld Inspection Frequency Extention (TAC No. ME6801),
dated February 2, 2012 (ML120260090).
(2) Arkansas Nuclear One, Unit No. 1 -Request for Alternative ANO1-ISI-023 to ASME CodeCase N-770-1 Volumetric Examination Frequency Requirements for the Fourth 10-YearInservice Inspection Interval (TAC No. MF3176),
dated October 29, 2014 (ML14282A479).
(3) Joseph M. Farley Nuclear Plant, Units 1 and 2 -Request for Alternative FNP-ISI-13 Regarding Deferral of Inservice Inspection of Reactor Pressure Vessel Cold Leg NozzleDissimilar Metal Welds (TAC Nos. ME9739 and ME 9740), dated August 8, 2013(ML13212A176).
Attachments (1) LTR-PAFM-15-27-NP, Technical Justification to Support Extended Volumetric Examination Interval for South Texas Unit 1 Reactor Vessel Inlet Nozzle to Safe End Dissimilar MetalWelds, April 2015 (Non-Proprietary).
(2) LTR-PAFM-15-27-P, Technical Justification to Support Extended Volumetric Examination Interval for South Texas Unit 1 Reactor Vessel Inlet Nozzle to Safe End Dissimilar MetalWelds, April 2015 (Proprietary).
Enclosure 2NOC-AE-15003250 Enclosure 2Application for Withholding Proprietary Information From Public Disclosure Westinghouse Electric CompanyW estinghouse Engineering, Equipment and Major Projects1000 Wesninghouse Drive, Building 3Cranberry  
: Township, Pennsylvania 16066USAU.S. Nuclear Regulatory Commission Direct tel: (412) 374-4643Document Control Desk Direct fax: (724) 940-856011555 Rockville Pike e-mail: greshaja@westinghouse.com Rockville, MD 20852 Proj letter: ST-WN-NOC-15-14 CAW-15-4167 April 22, 2015APPLICATION FOR WITHHOLDING PROPRIETARY INFORMATION FROM PUBLIC DISCLOSURE


==Subject:==
==Subject:==
LTR-PAFM-15-27-P, "rechnical Justification to Support Extended Volumetric ExaminationInterval for South Texas Unit 1 Reactor Vessel Inlet Nozzle to Safe End Dissimilar MetalWelds." (Proprietary)The proprietary information for which withholding is being requested in the above-referenced report isfurther identified in Affidavit CAW-15-4167 signed by the owner of the proprietary information,Westinghouse Electric Company LLC. The Affidavit, which accompanies this letter, sets forth the basison which the information may be withheld from public disclosure by the Commission and addresses withspecificity the considerations listed in paragraph (b)(4) of 10 CFR Section 2.390 of the Commission'sregulations.Accordingly, this letter authorizes the utilization of the accompanying Affidavit by STP NuclearOperating CompanyCorrespondence with respect to the proprietary aspects of the Application for Withholding or theWestinghouse Affidavit should reference CAW-15-4167, and should be addressed to James A. Gresham,Manager, Regulatory Compliance, Westinghouse Electric Company, 1000 Westinghouse Drive,Building 3 Suite 310, Cranberry Township, Pennsylvania 16066.Very truly yours,J James A. Gresham, ManagerRegulatory Compliance CAW-15-4167April 22, 2015AFFIDAVITCOMMONWEALTH OF PENNSYLVANIA:ssCOUNTY OF BUTLER:I, James A. Gresham, am authorized to execute this Affidavit on behalf of Westinghouse ElectricCompany LLC (Westinghouse), and that the averments of fact set forth in this Affidavit are true andcorrect to the best of my knowledge, information, and belief.trames A. Gresham, ManagerRegulatory Compliance 2CAW-15-4167(1) 1 am Manager, Regulatory Compliance, Westinghouse Electric Company LLC (Westinghouse),and as such, I have been specifically delegated the function of reviewing the proprietaryinformation sought to be withheld from public disclosure in connection with nuclear power plantlicensing and rule making proceedings, and am authorized to apply for its withholding on behalfof Westinghouse.(2) I am making this Affidavit in conformance with the provisions of 10 CFR Section 2.390 of theCommission's regulations and in conjunction with the Westinghouse Application for WithholdingProprietary Information from Public Disclosure accompanying this Affidavit.(3) I have personal knowledge of the criteria and procedures utilized by Westinghouse in designatinginformation as a trade secret, privileged or as confidential commercial or financial information.(4) Pursuant to the provisions of paragraph (b)(4) of Section 2.390 of the Commission's regulations,the following is furnished for consideration by the Commission in determining whether theinformation sought to be withheld from public disclosure should be withheld.(i) The information sought to be withheld from public disclosure is owned and has been heldin confidence by Westinghouse.(ii) The information is of a type customarily held in confidence by Westinghouse and notcustomarily disclosed to the public. Westinghouse has a rational basis for determiningthe types of information customarily held in confidence by it and, in that connection,utilizes a system to determine when and whether to hold certain types of information inconfidence. The application of that system and the substance of that system constituteWestinghouse policy and provide the rational basis required.Under that system, information is held in confidence if it falls in one or more of severaltypes, the release of which might result in the loss of an existing or potential competitiveadvantage, as follows:(a) The information reveals the distinguishing aspects of a process (or component,structure, tool, method, etc.) where prevention of its use by any ofWestinghouse's competitors without license from Westinghouse constitutes acompetitive economic advantage over other companies.
 
3CAW-15-4167(b) It consists of supporting data, including test data, relative to a process (orcomponent, structure, tool, method, etc.), the application of which data secures acompetitive economic advantage, e.g., by optimization or improvedmarketability.(c) Its use by a competitor would reduce his expenditure of resources or improve hiscompetitive position in the design, manufacture, shipment, installation, assuranceof quality, or licensing a similar product.(d) It reveals cost or price information, production capacities, budget levels, orcommercial strategies of Westinghouse, its customers or suppliers.(e) It reveals aspects of past, present, or future Westinghouse or customer fundeddevelopment plans and programs of potential commercial value to Westinghouse.(f) It contains patentable ideas, for which patent protection may be desirable.(iii) There are sound policy reasons behind the Westinghouse system which include thefollowing:(a) The use of such information by Westinghouse gives Westinghouse a competitiveadvantage over its competitors. It is, therefore, withheld from disclosure toprotect the Westinghouse competitive position.(b) It is information that is marketable in many ways. The extent to which suchinformation is available to competitors diminishes the Westinghouse ability tosell products and services involving the use of the information.(c) Use by our competitor would put Westinghouse at a competitive disadvantage byreducing his expenditure of resources at our expense.(d) Each component of proprietary information pertinent to a particular competitiveadvantage is potentially as valuable as the total competitive advantage. Ifcompetitors acquire components of proprietary information, any one component 4CAW-15-4167may be the key to the entire puzzle, thereby depriving Westinghouse of acompetitive advantage.(e) Unrestricted disclosure would jeopardize the position of prominence ofWestinghouse in the world market, and thereby give a market advantage to thecompetition of those countries.(f) The Westinghouse capacity to invest corporate assets in research anddevelopment depends upon the success in obtaining and maintaining acompetitive advantage.(iv) The information is being transmitted to the Commission in confidence and, under theprovisions of 10 CFR Section 2.390, it is to be received in confidence by theCommission.(v) The information sought to be protected is not available in public sources or availableinformation has not been previously employed in the same original manner or method tothe best of our knowledge and belief.(vi) The proprietary information sought to be withheld in this submittal is that which isappropriately marked in LTR-PAFM-15-27-P, "Technical Justification to SupportExtended Volumetric Examination Interval for South Texas Unit 1 Reactor Vessel InletNozzle to Safe End Dissimilar Metal Welds" (Proprietary), for submittal to theCommission, being transmitted by STP Nuclear Operating Company letter andApplication for Withholding Proprietary Information from Public Disclosure, to theDocument Control Desk. The proprietary information as submitted by Westinghouse isthat associated with technical justification to support extended volumetric examinationinterval for south Texas Unit 1 reactor vessel inlet nozzle to safe end dissimilar metalwelds, and may be used only for that purpose.(a) This information is part of that which will enable Westinghouse to:(i) Provide technical justification to support extended volumetricexamination interval for South Texas Unit 1 reactor vessel inlet nozzle tosafe end dissimilar metal welds.
LTR-PAFM-15-27-P, "rechnical Justification to Support Extended Volumetric Examination Interval for South Texas Unit 1 Reactor Vessel Inlet Nozzle to Safe End Dissimilar MetalWelds." (Proprietary)
5CAW-15-4167(b) Further this information has substantial commercial value as follows:(i) Westinghouse plans to sell the use of similar information to its customersfor the purpose of providing technical justification to support extendedvolumetric examination interval for reactor vessel nozzle to safe enddissimilar metal welds.(ii) Westinghouse can sell support and defense of industry guidelines andacceptance criteria for plant-specific applications.(iii) The information requested to be withheld reveals the distinguishingaspects of a methodology which was developed by Westinghouse.Public disclosure of this proprietary information is likely to cause substantial harm to thecompetitive position of Westinghouse because it would enhance the ability ofcompetitors to provide similar technical evaluation justifications and licensing defenseservices for commercial power reactors without commensurate expenses. Also, publicdisclosure of the information would enable o'thers to use the information to meet NRCrequirements for licensing documentation without purchasing the right to use theinformation.The development of the technology described in part by the information is the result ofapplying the results of many years of experience in an intensive Westinghouse effort andthe expenditure of a considerable sum of money.In order for competitors of Westinghouse to duplicate this information, similar technicalprograms would have to be performed and a significant manpower effort, having therequisite talent and experience, would have to be expended.Further the deponent sayeth not.
The proprietary information for which withholding is being requested in the above-referenced report isfurther identified in Affidavit CAW-15-4167 signed by the owner of the proprietary information, Westinghouse Electric Company LLC. The Affidavit, which accompanies this letter, sets forth the basison which the information may be withheld from public disclosure by the Commission and addresses withspecificity the considerations listed in paragraph (b)(4) of 10 CFR Section 2.390 of the Commission's regulations.
PROPRIETARY INFORMATION NOTICETransmitted herewith are proprietary and non-proprietary versions of documents furnished to the NRC inassociated with technical justification to support extended volumetric examination interval for southTexas Unit 1 reactor vessel inlet nozzle to safe end dissimilar metal welds, and may be used only for thatpurpose.In order to conform to the requirements of 10 CFR 2.390 of the Commission's regulations concerning theprotection of proprietary information so submitted to the NRC, the information which is proprietary in theproprietary versions is contained within brackets, and where the proprietary information has been deletedin the non-proprietary versions, only the brackets remain (the information that was contained within thebrackets in the proprietary versions having been deleted). The justification for claiming the informationso designated as proprietary is indicated in both versions by means of lower case letters (a) through (f)located as a superscript immediately following the brackets enclosing each item of information beingidentified as proprietary or in the margin opposite such information. These lower case letters refer to thetypes of information Westinghouse customarily holds in confidence identified in Sections (4)(ii)(a)through (4)(ii)(f) of the Affidavit accompanying this transmittal pursuant to 10 CFR 2.390(b)(1).COPYRIGHT NOTICEThe reports transmitted herewith each bear a Westinghouse copyright notice. The NRC is permitted tomake the number of copies of the information contained in these reports which are necessary for itsinternal use in connection with generic and plant-specific reviews and approvals as well as the issuance,denial, amendment, transfer, renewal, modification, suspension, revocation, or violation of a license,permit, order, or regulation subject to the requirements of 10 CFR 2.390 regarding restrictions on publicdisclosure to the extent such information has been identified as proprietary by Westinghouse, copyrightprotection notwithstanding. With respect to the non-proprietary versions of these reports, the NRC ispermitted to make the number of copies beyond those necessary for its internal use which are necessary inorder to have one copy available for public viewing in the appropriate docket files in the public documentroom in Washington, DC and in local public document rooms as may be required by NRC regulations ifthe number of copies submitted is insufficient for this purpose. Copies made by the NRC must includethe copyright notice in all instances and the proprietary notice if the original was identified as proprietary.}}
Accordingly, this letter authorizes the utilization of the accompanying Affidavit by STP NuclearOperating CompanyCorrespondence with respect to the proprietary aspects of the Application for Withholding or theWestinghouse Affidavit should reference CAW-15-4167, and should be addressed to James A. Gresham,Manager, Regulatory Compliance, Westinghouse Electric  
: Company, 1000 Westinghouse Drive,Building 3 Suite 310, Cranberry  
: Township, Pennsylvania 16066.Very truly yours,J James A. Gresham, ManagerRegulatory Compliance CAW-15-4167 April 22, 2015AFFIDAVIT COMMONWEALTH OF PENNSYLVANIA:
ssCOUNTY OF BUTLER:I, James A. Gresham, am authorized to execute this Affidavit on behalf of Westinghouse ElectricCompany LLC (Westinghouse),
and that the averments of fact set forth in this Affidavit are true andcorrect to the best of my knowledge, information, and belief.trames A. Gresham, ManagerRegulatory Compliance 2CAW-15-4167 (1) 1 am Manager, Regulatory Compliance, Westinghouse Electric Company LLC (Westinghouse),
and as such, I have been specifically delegated the function of reviewing the proprietary information sought to be withheld from public disclosure in connection with nuclear power plantlicensing and rule making proceedings, and am authorized to apply for its withholding on behalfof Westinghouse.
(2) I am making this Affidavit in conformance with the provisions of 10 CFR Section 2.390 of theCommission's regulations and in conjunction with the Westinghouse Application for Withholding Proprietary Information from Public Disclosure accompanying this Affidavit.
(3) I have personal knowledge of the criteria and procedures utilized by Westinghouse in designating information as a trade secret, privileged or as confidential commercial or financial information.
(4) Pursuant to the provisions of paragraph (b)(4) of Section 2.390 of the Commission's regulations, the following is furnished for consideration by the Commission in determining whether theinformation sought to be withheld from public disclosure should be withheld.
(i) The information sought to be withheld from public disclosure is owned and has been heldin confidence by Westinghouse.
(ii) The information is of a type customarily held in confidence by Westinghouse and notcustomarily disclosed to the public. Westinghouse has a rational basis for determining the types of information customarily held in confidence by it and, in that connection, utilizes a system to determine when and whether to hold certain types of information inconfidence.
The application of that system and the substance of that system constitute Westinghouse policy and provide the rational basis required.
Under that system, information is held in confidence if it falls in one or more of severaltypes, the release of which might result in the loss of an existing or potential competitive advantage, as follows:(a) The information reveals the distinguishing aspects of a process (or component, structure, tool, method, etc.) where prevention of its use by any ofWestinghouse's competitors without license from Westinghouse constitutes acompetitive economic advantage over other companies.
3CAW-15-4167 (b) It consists of supporting data, including test data, relative to a process (orcomponent, structure, tool, method, etc.), the application of which data secures acompetitive economic advantage, e.g., by optimization or improvedmarketability.
(c) Its use by a competitor would reduce his expenditure of resources or improve hiscompetitive position in the design, manufacture,  
: shipment, installation, assurance of quality, or licensing a similar product.(d) It reveals cost or price information, production capacities, budget levels, orcommercial strategies of Westinghouse, its customers or suppliers.
(e) It reveals aspects of past, present, or future Westinghouse or customer fundeddevelopment plans and programs of potential commercial value to Westinghouse.
(f) It contains patentable ideas, for which patent protection may be desirable.
(iii) There are sound policy reasons behind the Westinghouse system which include thefollowing:
(a) The use of such information by Westinghouse gives Westinghouse a competitive advantage over its competitors.
It is, therefore, withheld from disclosure toprotect the Westinghouse competitive position.
(b) It is information that is marketable in many ways. The extent to which suchinformation is available to competitors diminishes the Westinghouse ability tosell products and services involving the use of the information.
(c) Use by our competitor would put Westinghouse at a competitive disadvantage byreducing his expenditure of resources at our expense.(d) Each component of proprietary information pertinent to a particular competitive advantage is potentially as valuable as the total competitive advantage.
Ifcompetitors acquire components of proprietary information, any one component 4CAW-15-4167 may be the key to the entire puzzle, thereby depriving Westinghouse of acompetitive advantage.
(e) Unrestricted disclosure would jeopardize the position of prominence ofWestinghouse in the world market, and thereby give a market advantage to thecompetition of those countries.
(f) The Westinghouse capacity to invest corporate assets in research anddevelopment depends upon the success in obtaining and maintaining acompetitive advantage.
(iv) The information is being transmitted to the Commission in confidence and, under theprovisions of 10 CFR Section 2.390, it is to be received in confidence by theCommission.
(v) The information sought to be protected is not available in public sources or available information has not been previously employed in the same original manner or method tothe best of our knowledge and belief.(vi) The proprietary information sought to be withheld in this submittal is that which isappropriately marked in LTR-PAFM-15-27-P, "Technical Justification to SupportExtended Volumetric Examination Interval for South Texas Unit 1 Reactor Vessel InletNozzle to Safe End Dissimilar Metal Welds" (Proprietary),
for submittal to theCommission, being transmitted by STP Nuclear Operating Company letter andApplication for Withholding Proprietary Information from Public Disclosure, to theDocument Control Desk. The proprietary information as submitted by Westinghouse isthat associated with technical justification to support extended volumetric examination interval for south Texas Unit 1 reactor vessel inlet nozzle to safe end dissimilar metalwelds, and may be used only for that purpose.(a) This information is part of that which will enable Westinghouse to:(i) Provide technical justification to support extended volumetric examination interval for South Texas Unit 1 reactor vessel inlet nozzle tosafe end dissimilar metal welds.
5CAW-15-4167 (b) Further this information has substantial commercial value as follows:(i) Westinghouse plans to sell the use of similar information to its customers for the purpose of providing technical justification to support extendedvolumetric examination interval for reactor vessel nozzle to safe enddissimilar metal welds.(ii) Westinghouse can sell support and defense of industry guidelines andacceptance criteria for plant-specific applications.
(iii) The information requested to be withheld reveals the distinguishing aspects of a methodology which was developed by Westinghouse.
Public disclosure of this proprietary information is likely to cause substantial harm to thecompetitive position of Westinghouse because it would enhance the ability ofcompetitors to provide similar technical evaluation justifications and licensing defenseservices for commercial power reactors without commensurate expenses.
Also, publicdisclosure of the information would enable o'thers to use the information to meet NRCrequirements for licensing documentation without purchasing the right to use theinformation.
The development of the technology described in part by the information is the result ofapplying the results of many years of experience in an intensive Westinghouse effort andthe expenditure of a considerable sum of money.In order for competitors of Westinghouse to duplicate this information, similar technical programs would have to be performed and a significant manpower effort, having therequisite talent and experience, would have to be expended.
Further the deponent sayeth not.
PROPRIETARY INFORMATION NOTICETransmitted herewith are proprietary and non-proprietary versions of documents furnished to the NRC inassociated with technical justification to support extended volumetric examination interval for southTexas Unit 1 reactor vessel inlet nozzle to safe end dissimilar metal welds, and may be used only for thatpurpose.In order to conform to the requirements of 10 CFR 2.390 of the Commission's regulations concerning theprotection of proprietary information so submitted to the NRC, the information which is proprietary in theproprietary versions is contained within brackets, and where the proprietary information has been deletedin the non-proprietary  
: versions, only the brackets remain (the information that was contained within thebrackets in the proprietary versions having been deleted).
The justification for claiming the information so designated as proprietary is indicated in both versions by means of lower case letters (a) through (f)located as a superscript immediately following the brackets enclosing each item of information beingidentified as proprietary or in the margin opposite such information.
These lower case letters refer to thetypes of information Westinghouse customarily holds in confidence identified in Sections (4)(ii)(a) through (4)(ii)(f) of the Affidavit accompanying this transmittal pursuant to 10 CFR 2.390(b)(1).
COPYRIGHT NOTICEThe reports transmitted herewith each bear a Westinghouse copyright notice. The NRC is permitted tomake the number of copies of the information contained in these reports which are necessary for itsinternal use in connection with generic and plant-specific reviews and approvals as well as the issuance, denial, amendment,  
: transfer, renewal, modification, suspension, revocation, or violation of a license,permit, order, or regulation subject to the requirements of 10 CFR 2.390 regarding restrictions on publicdisclosure to the extent such information has been identified as proprietary by Westinghouse, copyright protection notwithstanding.
With respect to the non-proprietary versions of these reports, the NRC ispermitted to make the number of copies beyond those necessary for its internal use which are necessary inorder to have one copy available for public viewing in the appropriate docket files in the public documentroom in Washington, DC and in local public document rooms as may be required by NRC regulations ifthe number of copies submitted is insufficient for this purpose.
Copies made by the NRC must includethe copyright notice in all instances and the proprietary notice if the original was identified as proprietary.}}

Revision as of 00:18, 1 July 2018

South Texas Project, Unit 1 - Request for Relief from Code Case N-770-1, Subsection 2400 and Table 1 Inspection Frequency of Reactor Vessel Cold Leg Nozzle to Safe-End Welds with Flaw Analysis (Relief Request RR-ENG-3-17)
ML15133A130
Person / Time
Site: South Texas STP Nuclear Operating Company icon.png
Issue date: 04/24/2015
From: Berg M
South Texas
To:
Document Control Desk, Office of Nuclear Reactor Regulation
Shared Package
ML15133A119 List:
References
CAW-15-4167, NOC-AE-15003250, RR-ENG-3-17, STI: 34114282 ML15133A119
Download: ML15133A130 (19)


Text

JLMlA~r" Attachment 2 contains proprietary information and should be withheld from public disclosure inNuclear Operating Company accordance with 10 CFR 2.390South Tuas Pro/ect Electric Generatin$

Station P.O Bao 289 Wadsworth Texas 77483April 24, 2015NOC-AE-15003250 10 CFR 50.55a10 CFR 2.390File No.: D43.01U. S. Nuclear Regulatory Commission Attention:

Document Control DeskWashington, DC 20555-0001 South Texas Project Unit 1Docket No. STN 50-498Request for Relief from Code Case N-770-1, Subsection 2400 and Table 1 Inspection Frequency of Reactor Vessel Cold Leg Nozzle to Safe-end Welds with Flaw Analysis(Relief Request RR-ENG-3-17)

In accordance with the provisions of 10 CFR 50.55a(a)(3)(ii),

STP Nuclear Operating Company(STPNOC) requests relief for South Texas Project (STP) Unit 1 for performing the reactorvessel Cold Leg nozzle to safe-end weld inspections, covered by ASME Code Case N-770-1, bythe currently scheduled outage 1 RE19 (Fall 2015, Unit 1). This relief request proposesextending the inspection period by one operating cycle and performing the Code Case N-770-1inspections in conjunction with the implementation of an approved stress improvement processto mitigate primary water stress corrosion cracking (PWSCC) in the Hot and Cold Leg nozzle tosafe-end welds. The purpose of this relief request is to extend the Code Case N-770-1inspection period by one refueling cycle, approximately 18 months, until Refueling Outage1 RE20 scheduled for Spring 2017.10CFR50.55a(g)(6)(ii)(F)(1),

effective July 21, 2011, requires that the STP Inservice Inspection (ISI) program implement ASME Code Case N-770-1, related to examination requirements forClass 1 piping and nozzle dissimilar-metal butt welds. STPNOC has determined thatcompliance with these Code inspection requirements would result in unnecessary hardshipwithout a compensating increase in the level of quality and safety.By performing the Cold Leg weld inspections in conjunction with an approved stressimprovement process during Refueling Outage 1 RE20, STPNOC would reduce unnecessary radiation exposure to personnel and the need to perform a critical lift of the core barrel.STPNOC requests NRC review and approval of this relief request by September 1, 2015 tosupport the use of the proposed inspection date extension when authorized, as required by 10CFR 50.55a(a)(3).

STI: 34114282 NOC-AE-15003250 Page 2 of 3This letter contains two attachments.

Attachment 1 is non-proprietary; and Attachment 2 is theproprietary version of Attachment 1 and contains proprietary material that should be withheldfrom public disclosure as documented by the affidavits in Enclosure 2.There are no commitments in this letter.If there are any questions, please contact Rafael Gonzales at 361-972-4779, or me at 361-972-7030.Michael BergManager Design Engineering Testing and Programsrjg

Enclosures:

1. SOUTH TEXAS PROJECT UNIT 1, Request for Relief from Code Case N-770-1,Subsection 2400 and Table 1 Inspection Frequency of Reactor Vessel Cold Leg Nozzleto Safe-end Welds with Flaw Analysis (Relief Request RR-ENG-3-17)
2. Application for Withholding Proprietary Information From Public Disclosure Attachments:
1. LTR-PAFM-1 5-27-NP, Technical Justification to Support Extended Volumetric Examination Interval for South Texas Unit 1 Reactor Vessel Inlet Nozzle to Safe EndDissimilar Metal Welds, April 2015 (Non-Proprietary).
2. LTR-PAFM-15-27-P, Technical Justification to Support Extended Volumetric Examination Interval for South Texas Unit I Reactor Vessel Inlet Nozzle to Safe EndDissimilar Metal Welds, April 2015 (Proprietary).

NOC-AE-15003250 Page 3 of 3cc:(paper copy)(electronic copy)Regional Administrator, Region IVU.S. Nuclear Regulatory Commission 1600 East Lamar Boulevard Arlington, TX 76011-4511 Lisa M. RegnerSenior Project ManagerU.S. Nuclear Regulatory Commission One White Flint North (08H04)11555 Rockville PikeRockville, MD 20852NRC Resident Inspector U. S, Nuclear Regulatory Commission P. 0. Box 289, Mail Code: MN1 16Wadsworth, TX 77483Morgan, Lewis & Bockius LLPSteve Frantz, EsquireU.S. Nuclear Regulatory Commission Lisa M. RegnerNRG South Texas LPJohn RaganChris O'HaraJim von SuskilCPS EnergyKevin PolioCris EugsterL. D. BlaylockCrain Caton & James, P.C.Peter NemethCity of AustinCheryl MeleJohn WesterTexas Dept. of State Health ServicesRichard A. RatliffRobert Free Enclosure 1NOC-AE-15003250 Enclosure 1SOUTH TEXAS PROJECT UNIT 1, Request for Relief from Code Case N-770-1, Subsection 2400and Table 1 Inspection Frequency of Reactor Vessel Cold Leg Nozzle to Safe-end Welds with FlawAnalysis (Relief Request RR-ENG-3-17)

Enclosure 1NOC-AE-15003250 Page 1 of 7SOUTH TEXAS PROJECT UNIT 1Request for Relief from Code Case N-770-1, Subsection 2400 and Table 1 Inspection Frequency ofReactor Vessel Cold Leg Nozzle to Safe-end Welds with Flaw Analysis(Relief Request RR-ENG-3-17)

A. ASME Corn ponent(s)

AffectedThe affected components are STP Unit 1 reactor vessel Cold Leg nozzle to safe-end welds(Table 1), which are Alloy 600 welds subject to Code Case N-770-1 (Reference 1).Table 1 -STP Unit 1reactor vessel Cold Lea nozzle to safe-end weldsUNIT 1CATEGORY ITEMNO STP COMP ID COMPDESCSUMMARYNO N-770-1 B 101350 RPV1-N2ASE SAFE END TORPV LOOP AINLET NOZZLEN-770-1 B 101485 RPV1-N2BSE SAFE END TORPV LOOP BINLET NOZZLEN-770-1 B 101635 RPV1-N2CSE SAFE END TORPV LOOP CINLET NOZZLEN-770-1 B 101775 RPV1-N2DSE SAFE END TORPV LOOP DINLET NOZZLEB. Applicable ASME Code Edition and AddendaASME Section Xl 2004 Edition (Reference 2)Code Case N-770-1 as referenced in 10CFR50.55a(g)(6)(ii)(F)(1).

C. Applicable ASME Code Requirement Table 1 of Code Case N-770-1 requires volumetric examination of essentially 100% of Inspection Item B pressure retaining welds once every second inspection period, not to exceed 7 years.This is the third In-service Inspection (ISI)interval beginning September 25, 2010 throughSeptember 24, 2020.D. Reason for Relief from Code Requirements STPNOC is requesting a relief to extend the Cold Leg weld inspections one cycle(approximately 18 months) to Spring 2017 during Refueling Outage 1 RE20. During1 RE20, STPNOC will be performing mitigation of primary water stress corrosion cracking(PWSCC) in the Cold Leg nozzle to safe-end welds using a stress improvement processwhich requires the performance of a critical core barrel lift. If relief is granted for the ColdLeg weld inspection extension, STP can perform the inspections and the mitigation ofPWSCC during the same evolution, reducing the risk for performing two separate criticallifts and adhering to best "As Low As Reasonably Achievable" (ALARA) practices.

Enclosure 1NOC-AE-15003250 Page 2 of 7E. Proposed Alternative and Basis for Use:10CFR50.55a(a)(3) states in part:Any proposed alternatives must be submitted and authorized prior to implementation.

The applicant or licensee shall demonstrate that:(i) the proposed alternatives would provide an acceptable level of quality and safety, or(ii) compliance with the specified requirements of this section would result in hardship or unusualdifficulty without a compensating increase in the level of quality and safety.STPNOC believes that the proposed alternative inspection schedule presented in this requestprovides an acceptable level of quality and safety. STPNOC proposes a one-time extension toCode Case N-770-1, Table 1, Inspection Item B, volumetric examinations from a period not toexceed 7 years to a one time period not to exceed 8 years for STP Unit 1.During the Unit 1 Spring 2017 refueling outage, STPNOC will perform the mitigation of PWSCC onthe reactor vessel inlet and outlet nozzle to safe end Alloy 82/182 dissimilar metal (DM) welds.STPNOC plans to use a non-welded stress improvement method (meeting the performance criteriaof Code Case N-770-1 Appendix

1) as the mitigation process to minimize the potential of PWSCC bypermanently eliminating the tensile stress through approximately 50% of the inner DM weld wallthickness.

Examination of Code Case N-770-1 Item B (Cold Leg) welds are performed from the InsideDiameter (ID) in Unit 1 due to limited access from the outside surface of the pipe. The inspection ofItem B (Cold Leg) welds from the ID requires removal of the reactor vessel core barrel.Removing the reactor vessel lower internals assembly (core barrel) is considered to be a critical liftdue to the weight of the component, the tight clearances

involved, and the radiation emitted by theassembly.

For these reasons, only personnel directly involved with the movement of the internals are typically allowed in containment during the evolution.

Remote cameras are utilized to allow mostpersonnel involved with the lift to be outside of the refueling cavity area to minimize personnel radiation exposure.

The lower internals lifts are performed solely by viewing cameras.

If the needarises the Polar Crane operator is instructed to sit on the floor of the cab or behind shielding and notto raise his head above the cab area of the crane to maintain his radiation dose as low asreasonably achievable (ALARA).

Enclosure 1NOC-AE-15003250 Page 3 of 7For STP, removing the core barrel requires that it be raised above the refueling cavity water levelduring transfer from the reactor vessel to the storage stand location.

The radiation exposure levelsfor this activity can be high and necessitate evacuation of personnel from containment andinstallation of shielding for the polar crane operator(s).

In addition, the dose rates in the area wouldincrease due to the presence of the reactor vessel in the temporary storage location.

Aligning the N-770-1 inspection with the non-welded stress improvement method activity would reduceunnecessary radiation exposure to personnel.

Eliminating the need to remove the core barrel andlower internals during 1 RE19 could save approximately 610.5 mrem of dose.The total dose attributed to removal of the core barrel and lower internals was estimated based ondata from 2RE 14, the most recent outage when the core barrel was removed.

The total dose for theactual work activities to remove and install the reactor core barrel and lower internals during 2RE14was 123 mrem. The core barrel was transferred to the Lower Internal Storage Area (LISA) where itwas stored underwater for 13 days. The dose rates in the vicinity of the LISA with the core barrelpresent were compared to the dose rates without the core barrel present, and the approximate increase in dose rates in the general area walkway was 1.3 mrem per hour. Dose rates weremeasured on the South end of the 68' elevation of the Reactor Containment Building (RCB), whichis a general area walkway and a common travel path for workers inside containment.

During the 13days that the core barrel was stored in the LISA, workers could have received additional dose ofapproximately 487.5 mrem1 (see assumptions below). Therefore, the total dose associated withmoving and storing the core barrel and lower internals is 610.5 mrem.Assumptions

1. The total time the core barrel remained in the LISA, and thus, caused increase dose rates inthe general area walkway was 13 days.2. The total RWP-hours during those 13 days was approximately 37,500 hours0.00579 days <br />0.139 hours <br />8.267196e-4 weeks <br />1.9025e-4 months <br />.3. The total number of hours that workers may have spent in the vicinity of the 68' with higherdose rates is approximately 1% of the total RWP-hours

= 375 hours0.00434 days <br />0.104 hours <br />6.200397e-4 weeks <br />1.426875e-4 months <br />.4. The average increase in dose rates in the general area walkway was 1.3 mrem/hour.

Calculation:

375 hours0.00434 days <br />0.104 hours <br />6.200397e-4 weeks <br />1.426875e-4 months <br /> x 1.3 = 487.5 mremOperating experience on Primary Water Stress Corrosion Cracking (PWSCC) of Alloy 82/182 weldsshows that weld repairs performed during original plant construction are a significant contributor inthe initiation and propagation of cracking.

A review of the construction records and a weld repairsearch performed for the STP Unit 1 Reactor Vessel nozzle Alloy 82/182 welds did not identify anyweld repairs performed on these welds during original plant construction.

Enclosure 1NOC-AE-15003250 Page 4 of 7During the Fall 2009 Unit 1 refueling outage, a volumetric examination was performed to thespecifications of ASME Xl Appendix VIII along with a supplemental eddy current test. In April 2014,ultrasonic (volumetric) and eddy current (surface) exams were performed on the STP Unit 1 Hot Legwelds and no indications were identified.

In fall 2015, ultrasonic (volumetric) and eddy current(surface) exams are scheduled to be performed on the STP Unit 1Cold Leg welds to meet therequirement of N-770-1.

The absence of any indications in the Hot Leg welds in 2014 providesadded assurance that the one time extension of the inspection of the Cold Leg welds byapproximately 18 months provides an acceptable level of quality and safety.STP will perform non-welded stress improvement method on the reactor vessel inlet and outletnozzle to safe end welds during the 1RE20 refueling outage scheduled for spring 2017. Thisproposed approach reduces radiological exposure and personnel safety hazards associated withcritical lifting of the reactor vessel lower internals assembly (core barrel).

Therefore, deferral of theCold Leg Nozzle inspections for STP Unit 1 refueling outage would eliminate the increased radiation exposure associated with the removal of the core barrel.Technical BasisElectric Power Research Institute (EPRI) Technical Report for Materials Reliability Program:

PWRReactor Coolant System Cold-Loop Dissimilar Metal Butt Weld Reexamination Interval Extension, MRP-349 (Reference

3) provides the basis for extension of the current volumetric inspection intervalfor the Reactor Pressure Vessel (RPV) Cold Leg DM welds from every second inspection period or 7years, as currently required by Code Case N-770-1, to 8 years in the current inspection interval.

Insummary, the basis for one time extension of Code Case N-770-1, Table 1, Inspection Item B,volumetric examinations is: (1) there has been no service experience with cracking found in RPVCold Leg DM welds, (2) crack growth rates in RPV Cold Leg DM welds are small, and (3) likelihood of cracking or through wall leaks is very small in RPV Cold Leg DM welds. This technical basisdemonstrates that the re-examination interval can be extended to 8 years while maintaining anacceptable level of quality and safety.In addition, a site specific flaw tolerance analysis has been performed to determine the largest initialaxial and circumferential flaws that could be left behind in service and remain acceptable betweenthe planned examinations (Reference 4). This maximum allowable flaw size could then becompared to any flaw size detected during inlet nozzle DM weld examinations.

The attachment (Attachment 1 Non-proprietary and Attachment 2 Proprietary) to this enclosure contains the flawtolerance analysis in Reference 4.Service Experience The STP Unit 1 Cold Leg welds were last examined in Fall 2009 using remote mechanized examinations from the ID. The examinations were performed in accordance with Appendix VIII usingperformance demonstrated methods where 100% of the flaws in the test specimens were detected.

In addition, an eddy current examination was performed on the inside (or wetted) surface to inspectfor surface connected flaws. No recordable indications were identified during the 2009examinations.

Additionally, all volumetric examinations of the STP Unit 1 Cold Leg welds prior to2009 did not identify any indications requiring resolution.

The technique used in site specific examsincluded 100% coverage for axial and circumferential flaws. In these exams, data is obtained usingencoded techniques allowing the data to be reviewed by multiple qualified examiners.

Site specificmock-ups were not used because of the flat, uniform surface associated with performance of theseexaminations from the ID. These techniques provide strong assurance that flaws will be detected Enclosure 1NOC-AE-15003250 Page 5 of 7during inspections.

Each STP Unit 1 Cold Leg is exposed to approximately 5630F (Cold LegTemperature) during normal plant operation.

Crack Growth Rates (Flaw Tolerance)

All of the flaw tolerance analyses performed to date have shown that the critical crack sizes in large-diameter butt welds operating at Cold Leg temperatures are very large. Assuming that a flaw isinitiated, the time required for the flaw to grow to through-wall is in excess of 20 years in most casesanalyzed.

The time to grow from a through-wall leak to a crack equal to the critical crack size can bein excess of 40 years.More recent analyses have been performed for the RPV nozzles using through-wall residual stressdistributions that were developed based on the most recent guidance (Reference 3). These analyseshave shown that the flaw tolerance of these locations is high and postulated circumferential flaws willnot reach the maximum ASME allowable depth in less than 10 years. Crack growth analysis isgiven for limiting plants part-circumferential through-wall flaws in Table 5-2 of MRP-349.Probability of Crackinq or Through Wall LeaksAnalyses have been performed to calculate the probability of failure for Alloy 82/182 welds usingboth probabilistic fracture mechanics and statistical methods.

Both approaches have shown that thelikelihood of cracking or through-wall leaks in large-diameter Cold Led welds is very small.Furthermore, sensitivity studies performed using probabilistic fracture mechanics have shown thateven for the more limiting high temperature locations, more frequent inspections than required bySection Xl, such as that in MRP-139 (Reference

5) or Code Case N-770-1, have only a small benefitin terms of risk.Though past service experience may not be an absolute indicator of the likelihood of future cracking, the experience provides an indication of the relative likelihood of cracking in Cold Leg temperature locations versus Hot Leg temperature locations.

While there is a significant amount of PWSCCservice experience in Hot Leg locations, the number of indications in large-bore butt welds is stillsmall relative to the number of potential locations.

Also, all indications have been detected beforethey were a safety concern.

Therefore, if Hot Leg PWSCC is a leading indicator for Cold LegPWSCC and the higher frequency of inspections will be maintained for the Hot Leg locations, it isreasonable to conclude that a moderately less rigorous inspection schedule would be capable ofdetecting any Cold Leg indications before they became large enough to be a significant concern.

Enclosure 1NOC-AE-15003250 Page 6 of 7Table 2 below provides a summary of the latest Nozzle to Safe-End Welds inspection for STP Unit 1(1 RE18) and evaluation of the recorded indications.

This information confirms that satisfactory examinations have been performed on the STP Unit 1 Dissimilar Metal Welds.Table 2: Information Pertaining to Class 1 Piping and Nozzle Dissimilar-Metal Butt WeldsInspection

-STP Unit 1Inspection During the most recent inservice inspection, all Code Case N-770-1Methodology:

Inspection Item A-2 (Hot Leg) welds, were governed by the ASME SectionXl, 2004 Edition, with no Addenda, Code Case N-770-1 as incorporated byreference 10CFR50.55a.

Number of past Cold Leg examinations were performed with 10-Year inservice inspections inspections:

1RE08 (1999) and 1RE15 (2009).Number of There were no recordable indications identified during the most recentindications found: inservice inspection.

Proposed The third inservice inspection is currently scheduled to be performed ininspection 2015 and 2020. Pending approval of this relief request, the Unit 1 inspection schedule for would be (Baseline Examination after Mitigation) 2017 and 2027.balanceof plant life:F. Duration of Prooosed Alternative This request is applicable to STPNOC's ISI program for the third interval for STP Unit 1 and is not toexceed 18 months to Spring 2017 for Refueling Outage 1 RE20.

Enclosure 1NOC-AE-15003250 Page 7 of 7G. References

1. Code Case N-770-1, Alternative Examination Requirements and Acceptance Standards forClass 1 PWR Piping and Vessel Nozzle Butt Welds Fabricated with UNS N06082 or UNSW86182 Weld Filler Material With or Without Application of listed Mitigation Activities SectionXI, Division 1.2. ASME Boiler and Pressure Vessel Code,Section XI, 2004 Edition No Addenda, AmericanSociety of Mechanical Engineers, New York.3. EPRI, Materials Reliability Program:

PWR Reactor Coolant System Cold-Loop Dissimilar Metal Butt Weld Reexamination Interval Extension (MRP-349),

August 2012, (1025852).

4. Technical Justification to Support Extended Volumetric Examination Interval for South TexasUnit 1 Reactor Vessel Inlet Nozzle to Safe End Dissimilar Metal Welds, LTR-PAFM-15-27-P, Westinghouse, April 2015.5. Material Reliability Program:

Primary System Piping Butt Weld Inspection and Evaluation Guideline (MRP-139, Revision 1), December 2008, (1015009).

H. Precedents Relief from this examination requirement to apply the proposed alternative at the South TexasProject was previously approved by the NRC for the following (with ADAMS Accession No.references):

(1) Indian Point Nuclear Generating Unit No. 2 -Request for Relief Request No. IP2-lSI-RR-14, Code Case N-770-1, Reactor Coolant System Cold Leg Nozzle Weld Inspection Frequency Extention (TAC No. ME6801),

dated February 2, 2012 (ML120260090).

(2) Arkansas Nuclear One, Unit No. 1 -Request for Alternative ANO1-ISI-023 to ASME CodeCase N-770-1 Volumetric Examination Frequency Requirements for the Fourth 10-YearInservice Inspection Interval (TAC No. MF3176),

dated October 29, 2014 (ML14282A479).

(3) Joseph M. Farley Nuclear Plant, Units 1 and 2 -Request for Alternative FNP-ISI-13 Regarding Deferral of Inservice Inspection of Reactor Pressure Vessel Cold Leg NozzleDissimilar Metal Welds (TAC Nos. ME9739 and ME 9740), dated August 8, 2013(ML13212A176).

Attachments (1) LTR-PAFM-15-27-NP, Technical Justification to Support Extended Volumetric Examination Interval for South Texas Unit 1 Reactor Vessel Inlet Nozzle to Safe End Dissimilar MetalWelds, April 2015 (Non-Proprietary).

(2) LTR-PAFM-15-27-P, Technical Justification to Support Extended Volumetric Examination Interval for South Texas Unit 1 Reactor Vessel Inlet Nozzle to Safe End Dissimilar MetalWelds, April 2015 (Proprietary).

Enclosure 2NOC-AE-15003250 Enclosure 2Application for Withholding Proprietary Information From Public Disclosure Westinghouse Electric CompanyW estinghouse Engineering, Equipment and Major Projects1000 Wesninghouse Drive, Building 3Cranberry

Township, Pennsylvania 16066USAU.S. Nuclear Regulatory Commission Direct tel: (412) 374-4643Document Control Desk Direct fax: (724) 940-856011555 Rockville Pike e-mail: greshaja@westinghouse.com Rockville, MD 20852 Proj letter: ST-WN-NOC-15-14 CAW-15-4167 April 22, 2015APPLICATION FOR WITHHOLDING PROPRIETARY INFORMATION FROM PUBLIC DISCLOSURE

Subject:

LTR-PAFM-15-27-P, "rechnical Justification to Support Extended Volumetric Examination Interval for South Texas Unit 1 Reactor Vessel Inlet Nozzle to Safe End Dissimilar MetalWelds." (Proprietary)

The proprietary information for which withholding is being requested in the above-referenced report isfurther identified in Affidavit CAW-15-4167 signed by the owner of the proprietary information, Westinghouse Electric Company LLC. The Affidavit, which accompanies this letter, sets forth the basison which the information may be withheld from public disclosure by the Commission and addresses withspecificity the considerations listed in paragraph (b)(4) of 10 CFR Section 2.390 of the Commission's regulations.

Accordingly, this letter authorizes the utilization of the accompanying Affidavit by STP NuclearOperating CompanyCorrespondence with respect to the proprietary aspects of the Application for Withholding or theWestinghouse Affidavit should reference CAW-15-4167, and should be addressed to James A. Gresham,Manager, Regulatory Compliance, Westinghouse Electric

Company, 1000 Westinghouse Drive,Building 3 Suite 310, Cranberry
Township, Pennsylvania 16066.Very truly yours,J James A. Gresham, ManagerRegulatory Compliance CAW-15-4167 April 22, 2015AFFIDAVIT COMMONWEALTH OF PENNSYLVANIA:

ssCOUNTY OF BUTLER:I, James A. Gresham, am authorized to execute this Affidavit on behalf of Westinghouse ElectricCompany LLC (Westinghouse),

and that the averments of fact set forth in this Affidavit are true andcorrect to the best of my knowledge, information, and belief.trames A. Gresham, ManagerRegulatory Compliance 2CAW-15-4167 (1) 1 am Manager, Regulatory Compliance, Westinghouse Electric Company LLC (Westinghouse),

and as such, I have been specifically delegated the function of reviewing the proprietary information sought to be withheld from public disclosure in connection with nuclear power plantlicensing and rule making proceedings, and am authorized to apply for its withholding on behalfof Westinghouse.

(2) I am making this Affidavit in conformance with the provisions of 10 CFR Section 2.390 of theCommission's regulations and in conjunction with the Westinghouse Application for Withholding Proprietary Information from Public Disclosure accompanying this Affidavit.

(3) I have personal knowledge of the criteria and procedures utilized by Westinghouse in designating information as a trade secret, privileged or as confidential commercial or financial information.

(4) Pursuant to the provisions of paragraph (b)(4) of Section 2.390 of the Commission's regulations, the following is furnished for consideration by the Commission in determining whether theinformation sought to be withheld from public disclosure should be withheld.

(i) The information sought to be withheld from public disclosure is owned and has been heldin confidence by Westinghouse.

(ii) The information is of a type customarily held in confidence by Westinghouse and notcustomarily disclosed to the public. Westinghouse has a rational basis for determining the types of information customarily held in confidence by it and, in that connection, utilizes a system to determine when and whether to hold certain types of information inconfidence.

The application of that system and the substance of that system constitute Westinghouse policy and provide the rational basis required.

Under that system, information is held in confidence if it falls in one or more of severaltypes, the release of which might result in the loss of an existing or potential competitive advantage, as follows:(a) The information reveals the distinguishing aspects of a process (or component, structure, tool, method, etc.) where prevention of its use by any ofWestinghouse's competitors without license from Westinghouse constitutes acompetitive economic advantage over other companies.

3CAW-15-4167 (b) It consists of supporting data, including test data, relative to a process (orcomponent, structure, tool, method, etc.), the application of which data secures acompetitive economic advantage, e.g., by optimization or improvedmarketability.

(c) Its use by a competitor would reduce his expenditure of resources or improve hiscompetitive position in the design, manufacture,

shipment, installation, assurance of quality, or licensing a similar product.(d) It reveals cost or price information, production capacities, budget levels, orcommercial strategies of Westinghouse, its customers or suppliers.

(e) It reveals aspects of past, present, or future Westinghouse or customer fundeddevelopment plans and programs of potential commercial value to Westinghouse.

(f) It contains patentable ideas, for which patent protection may be desirable.

(iii) There are sound policy reasons behind the Westinghouse system which include thefollowing:

(a) The use of such information by Westinghouse gives Westinghouse a competitive advantage over its competitors.

It is, therefore, withheld from disclosure toprotect the Westinghouse competitive position.

(b) It is information that is marketable in many ways. The extent to which suchinformation is available to competitors diminishes the Westinghouse ability tosell products and services involving the use of the information.

(c) Use by our competitor would put Westinghouse at a competitive disadvantage byreducing his expenditure of resources at our expense.(d) Each component of proprietary information pertinent to a particular competitive advantage is potentially as valuable as the total competitive advantage.

Ifcompetitors acquire components of proprietary information, any one component 4CAW-15-4167 may be the key to the entire puzzle, thereby depriving Westinghouse of acompetitive advantage.

(e) Unrestricted disclosure would jeopardize the position of prominence ofWestinghouse in the world market, and thereby give a market advantage to thecompetition of those countries.

(f) The Westinghouse capacity to invest corporate assets in research anddevelopment depends upon the success in obtaining and maintaining acompetitive advantage.

(iv) The information is being transmitted to the Commission in confidence and, under theprovisions of 10 CFR Section 2.390, it is to be received in confidence by theCommission.

(v) The information sought to be protected is not available in public sources or available information has not been previously employed in the same original manner or method tothe best of our knowledge and belief.(vi) The proprietary information sought to be withheld in this submittal is that which isappropriately marked in LTR-PAFM-15-27-P, "Technical Justification to SupportExtended Volumetric Examination Interval for South Texas Unit 1 Reactor Vessel InletNozzle to Safe End Dissimilar Metal Welds" (Proprietary),

for submittal to theCommission, being transmitted by STP Nuclear Operating Company letter andApplication for Withholding Proprietary Information from Public Disclosure, to theDocument Control Desk. The proprietary information as submitted by Westinghouse isthat associated with technical justification to support extended volumetric examination interval for south Texas Unit 1 reactor vessel inlet nozzle to safe end dissimilar metalwelds, and may be used only for that purpose.(a) This information is part of that which will enable Westinghouse to:(i) Provide technical justification to support extended volumetric examination interval for South Texas Unit 1 reactor vessel inlet nozzle tosafe end dissimilar metal welds.

5CAW-15-4167 (b) Further this information has substantial commercial value as follows:(i) Westinghouse plans to sell the use of similar information to its customers for the purpose of providing technical justification to support extendedvolumetric examination interval for reactor vessel nozzle to safe enddissimilar metal welds.(ii) Westinghouse can sell support and defense of industry guidelines andacceptance criteria for plant-specific applications.

(iii) The information requested to be withheld reveals the distinguishing aspects of a methodology which was developed by Westinghouse.

Public disclosure of this proprietary information is likely to cause substantial harm to thecompetitive position of Westinghouse because it would enhance the ability ofcompetitors to provide similar technical evaluation justifications and licensing defenseservices for commercial power reactors without commensurate expenses.

Also, publicdisclosure of the information would enable o'thers to use the information to meet NRCrequirements for licensing documentation without purchasing the right to use theinformation.

The development of the technology described in part by the information is the result ofapplying the results of many years of experience in an intensive Westinghouse effort andthe expenditure of a considerable sum of money.In order for competitors of Westinghouse to duplicate this information, similar technical programs would have to be performed and a significant manpower effort, having therequisite talent and experience, would have to be expended.

Further the deponent sayeth not.

PROPRIETARY INFORMATION NOTICETransmitted herewith are proprietary and non-proprietary versions of documents furnished to the NRC inassociated with technical justification to support extended volumetric examination interval for southTexas Unit 1 reactor vessel inlet nozzle to safe end dissimilar metal welds, and may be used only for thatpurpose.In order to conform to the requirements of 10 CFR 2.390 of the Commission's regulations concerning theprotection of proprietary information so submitted to the NRC, the information which is proprietary in theproprietary versions is contained within brackets, and where the proprietary information has been deletedin the non-proprietary

versions, only the brackets remain (the information that was contained within thebrackets in the proprietary versions having been deleted).

The justification for claiming the information so designated as proprietary is indicated in both versions by means of lower case letters (a) through (f)located as a superscript immediately following the brackets enclosing each item of information beingidentified as proprietary or in the margin opposite such information.

These lower case letters refer to thetypes of information Westinghouse customarily holds in confidence identified in Sections (4)(ii)(a) through (4)(ii)(f) of the Affidavit accompanying this transmittal pursuant to 10 CFR 2.390(b)(1).

COPYRIGHT NOTICEThe reports transmitted herewith each bear a Westinghouse copyright notice. The NRC is permitted tomake the number of copies of the information contained in these reports which are necessary for itsinternal use in connection with generic and plant-specific reviews and approvals as well as the issuance, denial, amendment,

transfer, renewal, modification, suspension, revocation, or violation of a license,permit, order, or regulation subject to the requirements of 10 CFR 2.390 regarding restrictions on publicdisclosure to the extent such information has been identified as proprietary by Westinghouse, copyright protection notwithstanding.

With respect to the non-proprietary versions of these reports, the NRC ispermitted to make the number of copies beyond those necessary for its internal use which are necessary inorder to have one copy available for public viewing in the appropriate docket files in the public documentroom in Washington, DC and in local public document rooms as may be required by NRC regulations ifthe number of copies submitted is insufficient for this purpose.

Copies made by the NRC must includethe copyright notice in all instances and the proprietary notice if the original was identified as proprietary.