ML13151A030

Response to Request for Additional Information on License Renewal Pressurizer Surge Line Welds Inspection Program

ML13151A030
Person / Time
Site:	Turkey Point
Issue date:	05/20/2013
From:	Kiley M Florida Power & Light Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-2013-176
Download: ML13151A030 (16)

Text

0 May 20, 2013 FPL. L-2013-176 U.S. Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555-0001 Re: Turkey Point Units 3 and 4 Docket No. 50-250 and 50-251 License Renewal Pressurizer Surge Line Welds Inspection Program Response to Request for Additional Information

References:

1) FPL letter L-2012-214 to the USNRC, dated May 16, 2012, License Renewal Commitment Submittal of Pressurizer Surge Line Welds Inspection Program (ML12152A156)

2) NRC Letter, from Tracy J. Orf (NRC) to Mr. Mano Nazar (FPL), "Turkey Point Units 3 and 4 -Request for Additional Information Regarding License Renewal Commitment, Submittal of Pressurizer Surge Line Welds Inspection Program (TAC NOS. ME8717 and ME8718), dated December 13, 2012.3) FPL letter L-2012-444 to the USNRC, dated December 19, 2012, License Renewal Pressurizer Surge Line Welds Inspection Program Response to Request for Additional Information (ML 12361 A260)4) NRC Letter, from Farideh E. Saba (NRC) to Mr. Mano Nazar (FPL), "Turkey Point Units 3 and 4 -Request for Additional Information Regarding Request for NRC Review and Approval of the Pressurizer Surge Line Welds Inspection Program (TAC NOS. ME8717 and ME8718), dated May 6, 2013.On May 16, 2012 Florida Power and Light Company (FPL) submitted letter L-2012-214, (Reference 1), requesting review and approval of the inspection program for managing the effects of environmentally assisted fatigue of the Turkey Point Units 3 and 4 pressurizer surge line welds. By letter dated December 13, 2012, NRC provided FPL with a request for additional information (RAI) (Reference 2). On December 19, 2012 FPL submitted letter L-2012-444, with FPL's response to NRC's RAIs (Reference 3).Enclosure 2, Attachment 1 contained the updated inspection program for NRC review and approval.

Enclosure 2, Attachment 2 provided the technical basis for the inspection program (unchanged from previous submittal in Reference 1). A summary description of the Turkey Point Units 3 and 4, Surge Line Weld Inspection Program to be included in the Updated Final Safety Analysis Report (UFSAR) was also provided in Enclosure 2, Attachment 3.Additionally, FPL clarified errata corrections in letter L-2013-134, dated April 8, 2013.Florida Power & Light Company 9760 S.W. 344th Street Homestead, FL 33035 A )-7 L-2013-176 Page 2 By letter dated May 6, 2013, NRC issued a request for additional information (Reference

4) regarding the submittal in FPL letter L-2012-444, dated December 19, 2012.FPL's response to NRC's RAI dated May 6, 2013, is provided in the attached Enclosure 1. Based on FPL's RAI response, the revised aging management program is provided herein in Enclosure 2, Attachment

1. The technical analysis of the postulated flaw tolerance evaluation for the Pressurizer Surge Line Welds Inspection Program was last provided in L-2012-444, Enclosure 2, Attachment

2. This analysis remains unchanged.

The revised summary description of the Turkey Point Units 3 and 4, Surge Line Weld Inspection Program to be included in the Updated Final Safety Analysis Report (UFSAR)is provided herein in Enclosure 2, Attachment 2.Should there be any questions, please contact Mr. Robert J. Tomonto, Licensing Manager at 305 246-7327.Very truly yours, Michael Kiley Vice President Turkey Point Nuclear Plant Attachments Enclosure cc: Regional Administrator, USNRC Region II USNRC Senior Resident Inspector

-Turkey Point Plant FPL Letter L-2013-176 ENCLOSURE 1 Florida Power and Light Turkey Point Nuclear Plant Units 3 and 4 Responses to the NRC Request for Additional Information L-2013-176, Enclosure 1 NRC Questions and FPL Responses RAI Request In its letter dated December 19, 2012, the licensee stated that all of the welds within the scope of the program will be examined in accordance with the American Society of Mechanical Engineers Boiler and Pressure Vessel Code,Section XI, "Rules for Inservice Inspection of Nuclear Power Plant Components," (Section XI) Subsection IWB, for Class 1 welds. The licensee also stated that the examinations will be "surface/volumetric." The updated program description (provided in Attachment 1 of Enclosure 2 to licensee's December 19, 2012, letter) and the proposed updated final safety analysis report (UFSAR)summary description (provided in Attachment 3 of Enclosure 2 to the licensee's December 19, 2012, letter) also indicate that the examinations will be "surface/volumetric." To complete its review of the proposed inspection program, the NRC staff requests that for each weld within the scope of the program, the licensee specify whether the examinations will be surface, volumetric, or both. Based on the response, also provide the NRC the revised program description and the proposed UFSAR summary description as necessary.

Response The type of examinations proposed to be performed for all Turkey Point Units 3 and 4 Pressurizer Surge Line Weld within the scope of the aging management inspection program is both surface and volumetric.

The Aging Management Inspection Program for the aforementioned welds has been revised to clarify the type of examinations proposed.

The Revised program is provided in the attached Enclosure 2, Attachment

1. The response to this RAI does not change the technical analysis of the postulated flaw tolerance evaluation for the Pressurizer Surge Line Welds Inspection Program. This analysis, which was last provided to NRC in L-2012-444, Enclosure 2, Attachment 2, remains unchanged.

The proposed UFSAR summary description has been revised to include the clarification on the type of examinations proposed and it is provided herein in Enclosure 2, Attachment

2.

FPL Letter L-2013-176 ENCLOSURE 2 ATTACHMENT 1 Revised Florida Power and Light Turkey Point Nuclear Plant Units 3 and 4 Description of the Proposed Aging Management Program For Pressurizer Surge Line Welds Inspection Program L-2013-176, Enclosure 2, Attachment 1 Page 1 of 7 1. Background Florida Power & Light Company has a license renewal commitment for Turkey Point Units 3 and 4, to address the effects of environmentally assisted fatigue for the pressurizer surge line welds during the period of extended operation using one or more of the following approaches:

1. Further refinement of the fatigue analysis to lower the cumulative usage factor (CUF) to below 1.0, or 2. Repair of the affected locations, or 3. Replacement of the affected locations, or 4. Management of the effects of fatigue by an inspection program that has been reviewed and approved by the NRC.At Turkey Point Units 3 and 4, there are twelve pressurizer surge line weld locations subject to the effects of environmentally assisted fatigue (i.e., five welds in Unit 3, and seven welds in Unit 4). The critical weld locations of concern are the pressurizer surge nozzle-to-safe-end weld and the hot leg surge nozzle-to-pipe weld, where the calculated CUF was determined to exceed the ASME Code allowable usage factor of 1.0, when environmentally assisted fatigue (EAF) is considered during the period of extended operation.

By letter L-2001-075, dated April 19, 2001, (Reference 1), FPL committed to provide the NRC with inspection program details prior to entering the period of extended operation, should FPL selected option 4 (i.e., inspection) to manage environmentally assisted fatigue during the period of extended operation.

FPL has selected to age manage the effects of the environmentally assisted fatigue on the pressurizer surge line welds by an inspection program and flaw tolerance evaluation.

Accordingly, Sections 2, 3 and 4 of this attachment provide the description of the proposed Aging Management Program for the Turkey Point Units 3 and 4 Pressurizer Surge Line Welds Inspection Program, the Aging Management Program Attributes, and the Implementation of the Inspection Program, respectively, for NRC Staff review and approval.2. Description of the Proposed Aging Management Program for Turkey Point Units 3 and 4 Pressurizer Surge Line Welds Inspection Program The proposed Aging Management Program (AMP) for fatigue assessment is based on the approach documented in the ASME Boiler and Pressure Vessel Code, Section XI- Rules for Inservice Inspection of Nuclear Power Plant Components, Non-Mandatory Appendix L Operating Plant Fatigue Assessment.

A flaw tolerance evaluation was performed specifically for Turkey Point Units 3 and 4 in order to assess the operability of the surge line by using ASME Section XI Appendix L methodology and to determine the successive inspection schedule for the surge line welds with a postulated surface flaw. Two bounding weld locations were evaluated in detail. The two bounding weld locations of concern are the pressurizer surge nozzle-to-safe-end weld and the hot leg surge nozzle-to-pipe weld. Based on a comparison of geometry, material properties L-2013-176, Enclosure 2, Attachment I Page 2 of 7 and applicable loads, the results of the detailed evaluation of the two bounding locations are also applicable to all other in-between pipe weld locations on the surge line. The results of the crack growth for the pressurizer surge nozzle welds and hot leg surge nozzle welds are presented in Tables I and 2, respectively.

The technical analysis of the postulated flaw tolerance evaluation is provided in L-2012-444, Enclosure 2, Attachment 2.Table 1 Pressurizer Surge Nozzle Crack Growth Results Final Final Allowable Successive Max. Flaw Length(3)

Allowable Flaw Flaw Operating Inspection Flaw Type (1)(2) Flaw Depth Depth Length(2)

Period Schedule (5)l/rD (Deg.) (in.) a/t (in.) (in.) (in.) (months) (years)Circumferential 0.1 36 3.91 0.75 0.96 0.650 3.900 > 564(4) 10 Axial NA NA 2.96 0.70 0.90 0.492 2.952 324(4T 10 Table 2 Hot Leg Surge Nozzle Crack Growth Results Final Final Allowable Successive Max. Flaw Length 3) Allowable Flaw Flaw Operating Inspection Flaw Type ()(2) Flaw Depth Depth ength (2) Period Schedule (5)//YrD (Deg.) (in.) a/t (in.) (in.) (in.) (months) (years)Circumferential 0.1 36 3.37 0.42 0.422 0.386 2.316 > 720 10 Axial NA NA 1.94 0.75 0.76 0.323 1.938 624(4) 10 Notes for Tables 1 and 2: 1. The postulated initial flaw depth is 20% of the weld thickness (i.e., 0.201 inches) and the initial flaw length is 6 times its depth (i.e., 1.206 inches) per Appendix L guidelines.

2. A constant aspect ratio (a/l) of 1/6 is used in the crack growth analysis.3. Flaw length based on Inner Diameter (ID)4. Maximum flaw length is reached before the allowable flaw depth.5. Per Appendix L, if allowable operating period is equal or greater than 10 years, the successive inspection schedule shall be equal to the examination interval listed in the Turkey Point ASME Section XI schedule of Inservice Inspection (ISI) program of the component.

L-2013-176, Enclosure 2, Attachment I Page 3 of 7 Per the guidelines of Appendix L, Table L-3420-1, for the allowable operating periods listed in Tables 1 and 2, the successive inspection schedule for pressurizer surge line welds is determined to be ten years for either an axial or a circumferential postulated flaw. This inspection interval will be used for all pressurizer surge line welds as noted in Table 3.3. Aging Management Program Attributes The key attributes of the Turkey Point Units 3 and 4 Pressurizer Surge Line Weld Inspection Program that are used to describe the aging management program, are discussed below: 1. Scope of the Program All pressurizer surge line welds listed in Table 3 will be examined in accordance with ASME Section XI, IWB for Class 1 welds. The aging effect managed with these inspections is cracking due to environmentally assisted fatigue. In each 10-year ISI interval during the period of extended operation, all surge line welds in scope will be inspected in accordance with the Turkey Point ISI Program under Augmented and Other Programs.Based on postulated flaw tolerance analysis, and per the guidelines of ASME Code,Section XI, Appendix L, Table L-3420-1, the successive inspection schedule is determined to be ten years. This inspection interval will be used for all surge line piping welds in scope. Examination results are evaluated by qualified individuals in accordance with ASME Section XI acceptance criteria.

Components with indications that do not exceed the acceptance criteria are considered acceptable for continued service.2. Preventive Actions There are no specific preventive actions under this program to prevent the effects of aging.3. Parameter(s)

Monitored or Inspected A surface and volumetric inservice examination will be performed on all surge line welds as indicated in Table 3, "Turkey Point Units 3 and 4 Pressurizer Surge Line Welds Subject to Environmental Assisted Fatigue Inspection Program." 4. Detection of Aging Effects The degradation of surge line welds is determined by a surface and volumetric examination in accordance with the requirements of Turkey Point ISI Programs.

The frequency and scope of examination are sufficient to ensure that the aging effects are detected before the integrity of the surge line welds would be compromised.

5. Monitoring and Trending The frequency and scope of the examinations are sufficient to ensure that the environmentally assisted fatigue aging effect is detected before the intended function of these welds would be compromised.

Examinations will be performed in accordance with L-2013-176, Enclosure 2, Attachment I Page 4 of 7 the inspection intervals based on the results of the postulated flaw evaluation performed in accordance to the ASME Code Section XI, Appendix L methodology.

If flaws are identified in the pressurizer surge line welds, they will be evaluated by engineering to assess the effect of environmentally assisted fatigue (EAF), and to determine its impact on the EAF analysis (provided in L-2012-444, Enclosure 2, Attachment 2).Records of the examination procedures, results of activities, examination datasheets, and corrective actions taken or recommended will be maintained in accordance with the requirements of Turkey Point Units 3 and 4 ISI Program for ASME Section XI requirements.

6. Acceptance Criteria Acceptance standards for the inservice inspections are identified in Subsection IWB for Class 1 components.

Table IWB-2500-1 identifies references to acceptance standards listed in IWB-3500.

Relevant indications found in the surge line welds that are revealed by the inservice inspections, may require additional evaluation per the requirements of ASME Section XI, Appendix L.Indications that exceed the acceptance criteria are documented and evaluated in accordance with the Turkey Point Corrective Action Program. Operability of the surge line welds will require an IWB-3600 evaluation for acceptance based on engineering evaluation, repair, replacement or analytical evaluation.

Repairs or replacements will be performed in accordance with ASME Section XI, Subsection IWA-4000 and IWA-6000, as described by administrative procedure O-ADM-532, ASME Section XI Repair/Replacement Program.7. Corrective Actions Action Requests (ARs) are generated in accordance with the Turkey Point Corrective Action Program for any relevant indications of degradation.

Items with examination results that do not meet the acceptance criteria are subject to acceptance by evaluation and/or acceptance by repair or replacement in accordance with Subsection IWB-3600.8. Confirmation Process When degradation is identified in the pressurizer surge line welds, an engineering evaluation is performed to determine if the weld is acceptable for continued service or if repair or replacement is required.

The engineering evaluation includes probable cause, the extent of degradation, the nature and frequency of additional examinations, and, whether repair or replacement is required.Repair and/or replacement are performed in accordance with the requirements of ASME Section XI, Subsections IWA-4000 and IWA- 6000, and as implemented by the Turkey Point Units 3 and 4 ISI Program and by the associated administrative procedure 0-ADM-532, ASME Section XI Repair/Replacement Program.

L-2013-176, Enclosure 2, Attachment 1 Page 5 of 7 9. Administrative Controls Turkey Point IST Program will document the EAF inspection requirements for the Turkey Point Units 3 and 4 pressurizer surge line welds under the ISI Program section for Augmented and Other Inspection Programs.

In addition, a summary description of this aging management program will be included in the Updated Safety Analysis Report as a new Aging Management Program.10. Operating Experience A sample of the surge line welds have been examined surface and/or ultrasonically during the first three inservice inspection intervals in accordance with the requirements of the ASME Section XI, Subsection IWB. All surge line welds were volumetrically inspected during the fourth ISI interval and prior to entering period of extended operation.

To date, no reportable indications have been found in the subject pressurizer surge line welds. The programmatic operating experience (OE) activities described in relevant station procedures ensure the adequate evaluation of operating experience on an ongoing basis to address age-related degradation and aging management for the Turkey Point Units 3 and 4 Pressurizer Surge Line Weld Inspection Program.The proposed aging management program to examine all pressurizer surge line welds listed in Table 3, every 10 years (every ISI interval), provide reasonable assurance that potential environmental effects of fatigue will be managed such that all the pressurizer surge line welds within the scope of license renewal will continue to perform their intended functions for the extended period of operation.

Corrective actions, confirmation process and administrative controls for license renewal are in accordance with the site controlled quality assurance program pursuant to 10 CFR Part 50, Appendix B, and it covers all SSCs subject to an aging management review.4. Implementation of Pressurizer Surge Line Welds Inspection Program Upon approval of the proposed inspection program for the pressurizer surge line welds, related aging management program documents and the associated Updated Final Safety Analysis Report (UFSAR) sections will be updated accordingly.

5. References

1. Florida Power and Light letter to the NRC, L-2001-075, Response to Request for Additional Information for the Review of the Turkey Point Units 3 and 4 License Renewal Application, dated April 19, 2001.2. Structural Integrity Associates Engineering Report No. 1100756.401, Rev. 1, "Flaw Tolerance Evaluation of Turkey Point Surge Line Welds Using ASME Code Section XI, Appendix L" dated May 2012.3. FPL letter L-2012-214 to the USNRC, dated May 16, 2012, License Renewal Commitment Submittal of Pressurizer Surge Line Welds Inspection Program L-2013-176, Enclosure 2, Attachment 1 Page 6 of 7 4. Florida Power and Light letter to the NRC, L-2012- 444, dated December 19, 2012, License Renewal Pressurizer Surge Line Welds Inspection Program Response to Request for Additional Information.

5. Florida Power and Light letter to the NRC, L-2013-176, dated May 20, 2013, License Renewal Pressurizer Surge Line Welds Inspection Program Response to Request for Additional Information.

L-2013-176, Enclosure 2, Attachment 1 Page 7 of 7 TABLE 3 Turkey Point Units 3 and 4 Pressurizer Surge Line Welds Subject to Environmental Assisted Fatigue Inspection Program Last Allowable Operating Proposed Unit Weld Number Examination Period per ASME Performed and Appendix L Analysis AMP Inspections Results (See Note !) Type & Frequency I 12"-RC-130 1-1 2004 Greater than 10 Yrs Surface and Volumetric RCS Hot Leg Nozzle Satisfactory Once in 10-Year 2 12"-RC-1301-5 2012 Greater than 10 Yrs Surface and Volumetric Unit 3 Surge Pipe to pipe weld Satisfactory Once in 10-Year 3 12"-RC-1301-8 2006 Greater than 10 Yrs Surface and Volumetric Pipe to reducer at Pressurizer Satisfactory Once in 10-Year 4 14"-RC-1301-8A 2006 Greater than 10 Yrs Surface and Volumetric Reducer to safe end at pressurizer Satisfactory Once in 10-Year Surge Nozzle 5 14"- RC- 1301-9 2010 Greater than 10 Yrs Surface and Volumetric Safe End to Nozzle Satisfactory Once in 10-Year 12"-RC-1401-1 2008 Greater than 10 Yrs Surface and Volumetric At RCS Hot Leg Nozzle to pipe Satisfactory Once in 10-Year 2 12"-RC-1401-2 2008 Greater than 10 Yrs Surface and Volumetric Surge Pipe to pipe weld Satisfactory Once in 10-Year 3 Unit 4 12"-RC-1401-4 2008 Greater than 10 Yrs Surface and Volumetric Surge Pipe to pipe weld Satisfactory Once in 10 Year 4 12"-RC-1401-7 2006 Greater than 10 Yrs Surface and Volumetric Surge Pipe to pipe weld Satisfactory Once in 10-Year 5 12"-RC-1401-8 2006 Greater than 10 Yrs Surface and Volumetric Pipe to nozzle at Pressurizer Satisfactory Once in 10-Year 6 14"-RC-1401-8A 2006 Greater than 10 Yrs Surface and Volumetric Reducer to safe end at Pressurizer Satisfactory Once in 10-Year Surge Nozzle 7 14"- RC-1401-9 2009 Greater than 10 Yrs Surface and Volumetric Safe End to Nozzle Satisfactory Once in 10-Year Note 1: The inspection frequency as determined by ASME Code Section XI, Appendix L analysis is more than 10 years.In accordance to the requirements of Appendix L Table L-3420-1, the surge line welds will be examined once per 10 years, at the frequency of the Turkey Point ISI program FPL Letter L-2013-176 ENCLOSURE 2 ATTACHMENT 2 Florida Power and Light Turkey Point Nuclear Plant Units 3 and 4 Proposed UFSAR Update Proposed UFSAR update to chapter 16.1 on the Aging Management Program (AMP) for PZR Surge Line welds The Turkey Point approach to address reactor water environmental effects accomplishes two objectives.

First, the TLAA on fatigue design has been resolved by confirming that the original transient design limits remain valid for the 60-year operating period. confirmation by fatigue monitoring will ensure these transient design limits are not exceeded.

second, reactor water environmental effects on fatigue life are examined using the most recent data from laboratory simulation of the reactor coolant environment.

As a part of the industry effort to address environmental effects for operating nuclear power plants during the current 40-year licensing term, Idaho National Engineering Laboratories (INEL)evaluated, in NUREG/CR-6260, "Application of NUREG/CR-5999 Interim Fatigue Curves to Selected Nuclear Power Plant Components," March 1995, fatigue-sensitive component locations at plants designed by all four u. S. Nuclear Steam Supply System (NSSS) vendors. The pressurized water reactor (PWR)calculations, especially the early-vintage Westinghouse PWR calculations, are directly relevant to Turkey Point. The description of the "Older vintage Westinghouse Plant" evaluated in NUREG/CR-6260 matches Turkey Point with respect to design code. In addition, the transient cycles considered in the evaluation match or bound Turkey Point design.NUREG/CR-6260 calculated fatigue usage factors for critical fatigue-sensitive component locations for the early-vintage Westinghouse plant utilizing the interim fatigue curves provided in NUREG/CR-5999, "Interim Fatigue Design Curves for Carbon, Low-Alloy, and Austenitic Stainless Steels in LWR Environments," August 1993. The results of NUREG/CR-6260 analyses were then utilized to scale up the Turkey Point plant-specific usage factors for the same locations to account for environmental effects. Generic industry studies performed by EPRI and NEI were also considered in this aspect of the evaluation, as well as environmental data that have been collected and published subsequent to the generic industry studies.For the pressurizer surge line, FPL has previously inspected all surge line welds on both units during the fourth in-service inspection interval, and prior to entering the extended period of operation.

The results of these inspections were utilized to assess fatigue of the surge lines. In addition to these inspections, environmentally assisted fatigue of the surge lines welds is addressed using the following approach: Florida Power & Light elected to manage the effects of environmentally assisted fatigue of the pressurizer surge line welds by an aging management inspection program approved by the NRC.The aging management of the surge line will be accomplished by a combination of flaw tolerance analysis and in-service inspection.

The aging effect managed with these inspections is cracking due to environmentally assisted fatigue. The technical justification and inspection frequency are supported by the flaw tolerance analysis based on the methodology noted in ASME Section XI, Non-mandatory Appendix L, "Operating Plant Fatigue Assessment".

Based on postulated flaw tolerance analysis, and per the guidelines of ASME Code,Section XI, Appendix L, Table L-3420-1, the successive inspection schedule is determined to be ten years.All pressurizer surge line welds listed in scope of the aging management program will be examined in accordance with ASME Section XI, IWB for Class 1 welds. Inservice examinations for the surge line welds will be both surface and volumetric examinations.

In each 10-year ISI interval during the period of extended operation, all surge line welds will be inspected in accordance with the Turkey Point ISI Program under Augmented and other Programs.corrective actions, confirmation process and administrative controls related to license renewal are in accordance with the site controlled quality assurance program pursuant to 10 CFR Part 50, Appendix B, and covers all SSCs subject to an aging management review.