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MONTHYEARML0334201782003-12-0303 December 2003 Third Ten-Year Inservice Inspection (ISI) Interval Relief Request, ISI-3-8 Request to Use Alternative to ASME Code Rules for the Embedded Flaw Repair Process Project stage: Request ML0412604592004-05-0505 May 2004 SONGS, Units 2 & 3, Inservice Inspection Program Relief Request ISI-38, Embedded Flaw Repair Process Project stage: Other 2003-12-03
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Category:Inservice/Preservice Inspection and Test Report
MONTHYEARML13102A2972013-04-10010 April 2013 Special Report: Inspection of Steam Generator Tubes, Cycle 17 ML11139A2732011-05-17017 May 2011 Owner'S Report of Inservice Inspection, Form NIS-1 ML1107604852011-03-16016 March 2011 Third Ten-Year Inservice Interval Relief Request ISI-3-31, Flaw Evaluation of High-Energy Schedule 10s Emergency Core Cooling System Piping ML1019300792010-07-0808 July 2010 Submittal of Inservice Inspection Summary and Owner'S of Repair/Replacement Activities ML0935702702009-12-18018 December 2009 Response to Request for Additional Information Regarding Third Ten-Year Inservice Inspection (Isl) Interval Relief Request ISI-3-30, Inspection of Reactor Vessel Head In-Core Instrument Nozzles ML0908904022009-03-17017 March 2009 Owner'S Report of Inservice Inspection, Form NIS-1, for Period December 13, 2006 Through December 18, 2008 ML0905705542009-02-17017 February 2009 Day Post Refueling Outage Reactor Pressure Vessel Head Inspection Report ML0904200642009-01-28028 January 2009 Ultrasonic Test Results Related to Inservice Inspection (ISI) Interval Relief Request ISI-3-27 for the Use of Structural Weld Overlay and Associated Alternative Repair Techniques ML0826104582008-09-24024 September 2008 Upcoming Steam Generator Tube Inservice Inspection ML0824700242008-08-29029 August 2008 Correction to Third Ten-Year Inservice Inspection (ISI) Interval Requests ISI-3-27 and ISI-3-28, Use of Structural Weld Overlay and Associated Alternative Repair Techniques ML0817800982008-06-19019 June 2008 Transmittal of Special Report: Inspection of Steam Generator Tubes, Cycle 15 ML0810906302008-04-18018 April 2008 Owner'S Report of Lnservice Inspection, Form NIS-1 ML0721500462007-08-0101 August 2007 Third Ten-Year Inservice Inspection (ISI) Interval Request ISI-3-28 48-Hour Hold Period ML0707207342007-03-0909 March 2007 Owner'S Report of Inservice Inspection, Form NIS-1 San Onofre Nuclear Generating Station, Unit 3 ML0705704332007-02-21021 February 2007 Third Ten-Year Inservice Inspection (ISI) Interval Relief Request ISI-3-27 Use of Structural Weld Overlay and Associated Alternative Repair Techniques ML0632800242006-11-20020 November 2006 Additional Information Supporting Third Ten-Year Inservice Inspection (ISI) Interval Relief Request ISI-3-21 Request for Alternative to ASME Code Rules for the Embedded Flaw Repair Process for Control.. ML0632800232006-11-20020 November 2006 Additional Information Supporting the Third Ten-Year Inservice Inspection (ISI) Interval Relief Request ISI-3-24 for the Use of Structural Weld Overlay and Associated Alternative Repair Techniques ML0629802032006-10-23023 October 2006 Additional Information Supporting the Third Ten-Year Inservice Inspection Interval Relief Request ISI-3-24 and ISI-3-25 for the Use of Structural Weld Overlay and Associated Alternative Repair Techniques ML0627602332006-09-29029 September 2006 Additional Information Supporting Third Ten-Year Inservice Inspection (ISI) Interval Relief Requests ISI-3-24 and ISI-3-25 for the Use of Structural Weld Overlay and Associated Alternative Repair Techniques ML0620702622006-07-21021 July 2006 Owner'S Report of Inservice Inspection, Form NIS-1 ML0605504232006-02-22022 February 2006 Uni 2, Third Ten-Year Inservice Inspection (ISI) Interval Relief Request ISI-3-18 Use of Structural Weld Overlay and Associated Alternative Repair Techniques, ML0536200212005-12-23023 December 2005 Third Ten-Year Inservice Inspection Interval Relief Requests ISI-3-16, and ISI-3-17 to Support Pressurizer Lower Level Instrument Nozzle Repairs, San Onofre, Units 2 and 3 ML0508804232005-03-23023 March 2005 Owner'S Report of Inservice Inspection, Form NIS-1 San Onofre Nuclear Generating Station, Unit 3 ML0503301292005-01-28028 January 2005 Inservice Inspection Relief Request ISI-3-14 Request Use of Subsequent ASME Code Edition and Addenda for Pressure Testing of Welded Repair/Replacements in Third Inspection Interval ML0502100512005-01-14014 January 2005 Third Ten-Year Inservice Inspection (ISI) Interval Relief Request ISI-3-10, Revision 1 ML0430202682004-10-26026 October 2004 Third Ten-Year Inservice Inspection (ISI) Interval Relief Request ISI-3-13 Request to Use Alternative to ASME Code Rules for the Embedded Flaw Repair Process for Reactor Vessel Head Penetration 56 ML0430202752004-10-25025 October 2004 Special Report: Inservice Inspection of Steam Generator Tubes, Cycle 13 ML0427102772004-09-23023 September 2004 Report of Inservice Inspection of Steam Generator Tubes, Cycle 13 Additional Information ML0426403392004-09-15015 September 2004 Revision to the Duration of Relief Request ISI-3-7 Third 10-Year Inspection Interval ML0426102142004-09-15015 September 2004 Additional Information Supporting Third Ten-Year Inservice Inspection (ISI) Interval Relief Request ISI-3-1 Request to Use Risk-Informed Inservice Inspection (Ri ISI) ML0424504672004-08-26026 August 2004 Third Ten-Year Inservice Inspection (ISI) Interval Relief Request ISI-3-10 Revision 1, Regarding American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code Case N-638 Similar. ML0418903022004-07-0101 July 2004 Owner'S Report of Inservice Inspection, Form NIS-1 ML0412805032004-05-0303 May 2004 ASME Code Update for the Third Ten-Year Interval, Inservice Testing Program ML0411203482004-04-16016 April 2004 Second Ten-Year Inservice Inspection (ISI) Interval Relief Request RR-B-2-08 Regarding American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code Inspection Requirements ML0334201782003-12-0303 December 2003 Third Ten-Year Inservice Inspection (ISI) Interval Relief Request, ISI-3-8 Request to Use Alternative to ASME Code Rules for the Embedded Flaw Repair Process ML0318303272003-06-27027 June 2003 Report of Inservice Inspection of Steam Generator Tubes, Cycle 12 Additional Information ML0317502542003-06-18018 June 2003 ASME Code Update for Third Ten-Year Interval, Inservice Testing Program ML0312901052003-05-0505 May 2003 Owner'S Report of Inservice Inspection, Form NIS-1 for San Onofre, Unit 3 ML0230500202002-10-29029 October 2002 Second Ten-Year Interval Inservice Inspection Program Reactor Pressure Vessel Examination Relief Request B-2-05 San Onofre Nuclear Generating Station Unit 3 ML0227001372002-09-23023 September 2002 Second Interval, Third Period Refueling Outage-12, Inservice Inspection Summary Report ML0207002842002-02-26026 February 2002 Part 6 of 6, San Onofre Nuclear Generating Station, Units 2 & 3, Owner'S Report of Inservice Inspection, Form NIS-1, 10 Attachment-2 ML0207002692002-02-26026 February 2002 Part 5 of 6, San Onofre Nuclear Generating Station, Units 2 & 3, Owner'S Report of Inservice Inspection, Form NIS-1 ML0206706952002-02-26026 February 2002 Part 4 of 6, San Onofre Nuclear Generating Station, Units 2 & 3, Owner'S Report of Inservice Inspection, Form NIS-1 ML0206706742002-02-26026 February 2002 Part 2 of 6, San Onofre Nuclear Generating Station, Units 2 & 3, Owner'S Report of Inservice Inspection, from NIS-1, 10 Attachment-2 ML0206706642002-02-26026 February 2002 Part 2 of 6, San Onofre Nuclear Generating Station, Units 2 & 3, Owner'S Report of Inservice Inspection, from NIS-1, 10 Attachment-2 ML0206706442002-02-26026 February 2002 Part 1 of 6, San Onofre Nuclear Generating Station, Units 2 & 3, Owner'S Report of Inservice Inspection, Form NIS-1 2013-04-10
[Table view] Category:Letter
MONTHYEARIR 05000361/20240042024-08-0909 August 2024 NRC Inspection Report 05000361/2024004 and 05000362/2024004 ML24191A2472024-07-0202 July 2024 (Songs), Units 1, 2, and 3, and the Independent Spent Fuel Storage Installation - Revision to the ISFSI-Only Emergency Plan and Associated Changes to Emergency Plan Implementing Procedures ML24151A6482024-06-0303 June 2024 Changes in Reactor Decommissioning Branch Project Management Assignments for Some Decommissioning Facilities ML24141A0802024-05-15015 May 2024 (Songs), Units 1, 2 and 3 and Independent Spent Fuel Storage Installation - 2023 Annual Radiological Environmental Operating Report IR 05000361/20240022024-04-0101 April 2024 – NRC Inspection Report 050-00361/2024-002 and 050-00362/2024-002 ML24094A0642024-03-27027 March 2024 Independent Spent Fuel Storage Installation, Decommissioning Funding Status Report 2023 ML24065A0152024-02-28028 February 2024 Generation Station Units 1, 2 and 3, Annual Radioactive Effluent Release Report for Independent Spent Fuel Storage Installation 2023 ML24044A0812024-02-14014 February 2024 LTR-24-0008: NRC Response to Paul Blanch Email Safety of Spent Nuclear Fuel at SONGS ISFSI IR 05000361/20240012024-02-13013 February 2024 NRC Inspection Report 050-00361/2024-001 and 050-00362/2024-001 (1) ML24037A0542024-01-30030 January 2024 (Songs), Units 2 and 3, Submittal of Annual Corporate Financial Reports ML24022A1492024-01-17017 January 2024 Independent Spent Fuel Storage Installation, Revision 4 to the Physical Security Plan IR 05000361/20230062023-11-29029 November 2023 NRC Inspection Report 05000361/2023-006 and 05000362/2023-006 ML23333A0682023-11-22022 November 2023 (SONGS) Units 1, 2, 3 and Independent Spent Fuel Storage Installation - Notification of Change in Nuclear Officer IR 05000361/20230052023-10-11011 October 2023 NRC Inspection Report 05000361/2023005 and 05000362/2023005 ML23276A5942023-09-28028 September 2023 and Independent Spent Fuel Storage Installation - Supplement to Decommissioning Funding Status Reports ML23268A0922023-09-20020 September 2023 Generation Station, Units 1, 2 and 3, and the Independent Spent Fuel Storage Facility (ISFSI) - Re-Registration of Dry Fuel Storage Casks for Amended Certificate of Compliance No. 1040 IR 05000361/20230012023-09-13013 September 2023 NRC Inspection Report 05000361 2023-001 and 05000362 2023-004 ML23240A5372023-08-18018 August 2023 Confirmatory Survey Activities Summary and Results for the Unit 2 and 3 Intake Structures at the San Onofre Nuclear Generating Station San Clemente CA ML23129A1802023-06-14014 June 2023 Cover Letter to State of CA on Draft EA Regarding San Onofre ISFSI Updated DFPs IR 05000361/20230032023-05-31031 May 2023 NRC Inspection Report 05000361/2023003 and 05000362/2023003 IR 05000361/20230022023-05-23023 May 2023 NRC Inspection Report 05000361/2023-002 and 05000362/2023-002 ML23137A1032023-05-11011 May 2023 (Songs), Units 1, 2 and 3, and Independent Spent Fuel Storage Installation - 2022 Annual Radiological Environmental Operating Report ML23123A0932023-04-28028 April 2023 (Songs), Units 1, 2 and 3, Submittal of Annual Radioactive Effluent Release Report - 2022 ML23230A0882023-04-10010 April 2023 Independent Spent Fuel Storage Installation - Decommissioning Quality Assurance Plan ML23094A1332023-03-29029 March 2023 Nuclear Property Insurance ML23094A1272023-03-29029 March 2023 Independent Spent Fuel Storage Installation - 10 CFR 50.82(a)(8)(v and VII) and 10 CFR 72.30(c) Decommissioning Funding Status Report 2021 ML23062A1172023-02-28028 February 2023 Generation Station Units 1, 2 and 3, Annual Radioactive Effluent Release Report for Independent Spent Fuel Storage Installation - 2022 ML22361A1022023-02-24024 February 2023 Reactor Decommissioning Branch Project Management Changes for Some Decommissioning Facilities and Establishment of Backup Project Manager for All Decommissioning Facilities ML23059A2812023-02-22022 February 2023 (Songs), Units 1, 2 and 3, 2022 Annual Turtle Incidental Take Report ML23046A3792023-02-22022 February 2023 NRC Inspection Report 050-00361/2023-001 and 050-00362/2023-001 ML23045A2022023-02-0909 February 2023 Submittal of Annual Corporate Financial Reports for San Onofre Nuclear Generating Station (SONGS) Units 2 and 3 for Fy Ending June 30, 2022 ML22287A1352023-01-0505 January 2023 Issuance of Exemption from Title 10 of the Code of Federal Regulations Part 72.106(B), Independent Spent Fuel Storage Installation Controlled Area Boundary (L-2021-LLE-0056) ML22348A0622023-01-0404 January 2023 NRC to SCE, Transmittal of the National Marine Fisheries Service'S December 12, 2022, Letter of Concurrence for Decommissioning of San Onofre Nuclear Generating Statiion, Units 2 and 3 IR 05000206/20220062022-12-15015 December 2022 NRC Inspection Report 05000206/2022006, 05000361/2022-006, and 05000362/2022-006 ML22347A2122022-12-12012 December 2022 NMFS to NRC, Endangered Species Act Section 7(a)(2) Concurrence Letter for Decommissioning of the San Onofre Nuclear Generating Station ML22340A6652022-12-0505 December 2022 Letter from John Fassell, Chief; Re., State of California Department of Public Health Review and Comments on SONGS Draft Environmental Assessment ML22333A8192022-11-21021 November 2022 Submittal of San Onofre Nuclear Generating Station, Units 2 and 3, Defueled Safety Analysis Report, Revised November 2022 IR 05000361/20220052022-11-17017 November 2022 NRC Inspection Report 05000361/2022-005 and 05000362/2022-005 ML22301A1462022-10-20020 October 2022 Report of Violations of the National Pollutant Discharge Elimination System Permit San Onofre Nuclear Generating Station (Songs), Units 2 and 3 ML22277A0162022-09-29029 September 2022 Independent Spent Fuel Storage Installation Response to Request for Additional Information Regarding Request for Exemption from 10 CFR 72.106(b) IR 05000361/20220042022-09-26026 September 2022 NRC Inspection Report 05000361/2022-004 and 05000362/2022-004 ML22238A0552022-08-29029 August 2022 U.S. Nuclear Regulatory Commission'S Analysis of Southern California Edison'S Decommissioning Funding Status Report for San Onofre Nuclear Generating Station, Units 1, 2, and 3 ML22234A1602022-07-31031 July 2022 Final Report Per 10 CFR Part 21, Degraded Snubber SF1154 Hydraulic Fluid Batch No. 18CLVS431 ML22207B8612022-07-26026 July 2022 NRC (Public) Inspection Report 05000361/2022003; 05000362/2022003 IR 05000361/20220032022-07-26026 July 2022 NRC Inspection Report (Public) 05000361-2022003 and 05000362-2022003 (002) IR 05000361/20220022022-05-12012 May 2022 NRC Inspection Report 05000361/2022-002 and 05000362/2022-002 ML22136A0842022-05-12012 May 2022 Independent Spent Fuel Storage Installation, 2021 Annual Radiological Environmental Operating Report ML22122A0402022-04-28028 April 2022 (Songs), Units 1, 2 and 3 - Annual Radioactive Effluent Release Report - 2021 ML22105A5662022-04-0505 April 2022 20053 Letter - OI Closure to Licensee - Wrongdoing Signed ML22081A1692022-03-31031 March 2022 SONGS Application Acceptance Proposed Exemption from Title 10 of the CFR, Part 72.106(b), ISFSI Controlled Boundary 2024-08-09
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SOUTHERN CALIFORNIA A. Edward Scherer EDISON Manager of Nuclear Regulatory Affairs An EDISON INTERNATIONAL9 Company December 3, 2003 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001
Subject:
Docket Nos.60-361 and 50-362 Third Ten-Year Inservice Inspection (IS1) Interval Relief Request ISI-3-8 Request to Use Alternative To ASME Code Rules For The Embedded Flaw Repair Process San Onofre Nuclear Generating Station Units 2 and 3
Dear Sir or Madam,
This letter submits the Southern California Edison(SCE) Company's Relief Request ISI-3-8 to allow the use of the embedded flaw repair process as an alternative to the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code.
SCE will be performing inspections as required by the February 11, 2003, NRC Order EA-03-009, issuance of Order Establishing Interim Inspection Requirements for Reactor Pressure Vessel Head at Pressurized Water Reactors." SCE intends to use the embedded flaw repair process in the event repairs are required in the reactor pressure vessel head penetrations and/or the attachment welds.
Therefore, SCE requests NRC approval of Relief Request ISI-3-8 prior to February 9, 2004, when the next Unit 2 refueling outage is scheduled to begin.
Should you have any questions, please contact Mr. Jack Rainsberry, Manager, Plant Licensing at (949) 368-7420.
Sincerely, Enclosure cc: B. S. Mallett, Regional Administrator, NRC Region IV B. M. Pham, NRC Project Manager, San Onofre Units 2, and 3 C. C. Osterholtz, NRC Senior Resident Inspector, San Onofre Units 2 & 3 P.O. Box 128 San Clemente, CA 92674-0128 At 949-368-7501 Fax 949-368-7575
ENCLOSURE Relief Request ISI-3-8 Request To Use Alternative To ASME Code Rules For The Embedded Flaw Repair Process
10 CFR 50.55a Request for Relief ISI-3-8 Proposed Altemative In Accordance with 10 CFR 50.55a(a)(3)(1)
Alternative Provides Acceptable Level of Quality and Safety
1.0 ASME Code Components Affected
The reactor pressure vessel head (RPVH), which includes control element drive mechanism (CEDM) penetrations, 91 each, In-Core Instrumentation (ICI) penetrations, 10 each, and one head vent penetration on each reactor pressure vessel head, is an American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Section liI, Class 1 component.
2.0 Aplicable Code Edition and Addenda Reactor Vessel Construction Code, ASME Section 1II, 1971 Edition, through the Summer 1971 Addenda Code of Record for Current (Third) Ten-Year Inservice Inspection (ISI)
Interval, ASME Section Xi, 1995 Edition, through the 1996 Addenda 3.0 Aplicable Code Reauirements ASME XI, IWA-4410(a) states the repair/replacement activities, such as metal removal and welding, shall be performed in accordance with the Owner's Requirements and the original Construction Code of the component or system. The applicable Construction Code is ASME IlIl, 1971 Edition, through the Summer 1971 Addenda.
BASE METAL DEFECT REPAIRS ASME IlIl, NB-4131 states that defects in base metals, such as the RPVH penetration tubes, may be eliminated or repaired by welding, provided the defects are removed, repaired and examined in accordance with the requirements of NB-2500.
ASME IlIl, NB-2538 addresses elimination of base material surface defects and specifies defects are to be removed by grinding or machining. Defect removal must be verified by a magnetic particle or liquid penetrant examination using acceptance criteria of NB-2545 or NB-2546. If the removal process reduces the section thickness below the NB-3000 design thickness, then repair welding per NB-2539 is to be performed.
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10 CFR 50.55a Request for Relief ISI-3-8 3.0 Applicable Code Requirements (continued)
ASME III, NB-2539.1 addresses removal of defects and requires defects be removed or reduced to an acceptable size by suitable mechanical or thermal methods.
ASME ll, NB-2539.4 provides the rules for examination of the base material repair welds and specifies they shall be examined by the magnetic particle or liquid penetrant methods with acceptance criteria per NB-2545 and NB-2546. Additionally, if the depth of the repair cavity exceeds the lesser of 3/8" or 10% of the section thickness, the repair weld shall be examined by the radiographic method using the acceptance criteria of NB-5320.
WELD METAL DEFECT REPAIRS ASMEIll, NB-4451 states defects in weld metal shall be eliminated and, when necessary, repaired per NB-4452 and NB-4453.
ASME Ill, NB-4452 addresses elimination of weld metal surface defects and specifies defects are to be removed by grinding or machining. Defect removal must be verified by a magnetic particle or liquid penetrant examination using acceptance criteria of NB-5340 or NB-5350. If the removal process reduces the section thickness below the NB-3000 design thickness, then repair welding per NB-4453 is to be performed.
ASME ll, NB-4453.1 addresses removal of defects in welds and requires the defect removal be verified with magnetic particle or liquid penetrant examinations using acceptance criteria of NB-5340 or NB-5350, or in the case of partial penetration welds where the entire thickness of the weld is removed, and only a visual examination is required.
REQUESTED RELIEF Relief is requested from the requirements of ASME Xl, IWA-441 O(a), to perform repairs on the RPVH penetrations per the rules of Construction Code.
Relief is requested from the requirements in ASME ll, NB-4131, NB-2538 and NB-2539.1 to eliminate base material defects prior to repair welding.
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10 CFR 50.55a Request for Relief ISI-3-8 3.0 Applicable Code Requirements (continued)
REQUESTED RELIEF Relief is requested to use substitute examination methods in lieu of those specified in NB-2539.4 for the following cases:
- In the case of embedded flaw welds on the ID surface of the penetration tubes, eddy current and ultrasonic examinations will be performed on the overlay repair welds which are surface and volumetric examinations but are different methods than specified in NB-2539.4.
- Inthe case of embedded flaw welds on the OD surface of the penetration tubes, surface examinations using the liquid penetrant method will be performed on the overlay repair weld surface.
Additionally, ultrasonic examinations of the repair weld volume will be performed from the ID surface opposite the overlay repair weld.
The ultrasonic method is a different volumetric examination method than is specified in NB-2539.4.
Relief is requested from the requirements in ASME IlIl, NB-4451, NB-4452 and NB4453.1 to eliminate weld metal defects prior to repair welding.
4.0 Reason for the Reauest Southern California Edison (SCE) Company will be performing RPVH inspections during refueling outages to meet the requirements of the February 11, 2003, NRC Order EA-03-009 (Reference 1). SCE is anticipating the potential need to use the embedded flaw repair process if flaws are identified during these inspections. The proposed embedded flaw process as described in the May 16, 2003 letter from Westinghouse to the NRC (Reference 2), NRC Safety Evaluation Report which approved the Westinghouse embedded flaw process (Reference 3), and the October 1, 2003, letter from Westinghouse to the NRC (Reference 4) provides an acceptable alternative to repair reactor vessel head penetrations (RVHP).
5.0 Proposed Alternative and Basis for Use PROPOSED ALTERNATIVE Design, implementation of repairs, and inspections will be consistent with the information contained in References 2, 3, and 4.
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10 CFR 50.55a Request for Relief ISI-3-8 5.0 Proposed Alternative and Basis for Use (continued)
PROPOSED ALTERNATIVE (continued)
- The embedded flaw repair overlay welds on the penetration J-groove welds will consist of a minimum of 3 deposited layers.
- The embedded flaw repair overlay welds on the inside diameter (ID) and the outside diameter (OD) of the penetration tube material will consist of a minimum of 2 deposited layers of weld, consistent with Reference 4, to minimize welding induced residual stresses and material distortion. In the case of repairs on the ID surface, the 2 layer approach results in a reduced inlay excavation depth.
BASIS FOR USE In the NRC Safety Evaluation Report (SER) (Reference 3) the NRC staff concluded that, subject to the conditions of the SER, the embedded flaw process proposed provides an acceptable level of quality and safety. It also concluded that the SER and technical report may be referenced by licensees.
In both cases of the ID and the OD overlay repair welds, the proposed substitute examination methods have been previously demonstrated to be adequate for flaw detection and sizing as shown in Reference 4.
The embedded flaw repair process is considered a permanent repair that will last through the useful life of the RPVH. As long as a primary water stress corrosion cracking (PWSCC) flaw remains isolated from the primary water environment the only known mechanism for any further potential propagation is fatigue. The calculated fatigue usage in this region is very low, because the reactor vessel head region is isolated from the transients that affect the hot leg or cold leg piping.
The thickness of the weld used to embed the flaw has been set to provide a permanent embedment of the flaw. The embedded flaw process imparts less residual stresses than weld repair following the complete removal of the flaw.
Since Alloy 52 (690) weldment is considered highly resistant to PWSCC, a new PWSCC crack should not initiate and grow through the Alloy 52 overlay to reconnect the primary water environment with the embedded flaw. The resistance of the alloy 690 material has been demonstrated by laboratory testing, and in approximately 10 years of operational service in steam generator tubes, where no PWSCC has been found.
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10 CFR 50.55a Request for Relief ISI-3-8 5.0 Proposed Alternative and Basis for Use (continued)
BASIS FOR USE (continued)
Therefore, the embedded flaw repair process is considered to be an alternative to Code requirements that provides an acceptable level of quality and safety, as required by 10 CFR 50.55a(a)(3)(i).
6.0 Duration of Proposed Alternative Relief is requested for the third in-service inspection interval at SONGS Units 2 and 3, which is scheduled to end on August 17, 2013.
7.0 Precedents Letter from Stephen Dembeck (NRC) to G.R. Overbeck (APS) dated, September 25, 2003;
Subject:
Palo Verde Nuclear Generating Station, Units 1, 2, and 3, - Relief Request NOS. 20 and 21 Re: Alternatives to Inservice Inspection Program Flaw Repair Requirements (TAC NOS.
MB4498, MB4499, MB500, MB4645, MB4646, and MB4647)"
Letter From Richard J. Laufer (NRC) to L.W. Pearce (FENOC) dated May 14, 2003;
Subject:
"Beaver Valley Power Station, Units 1 and 2 -
Evaluation of Inservice Inspection (ISI) Relief Request BV3-RV-04 (TAC Nos. MB8172 and MB8173)"
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10 CFR 50.55a Request for Relief ISI-3-8 8.0 References
- 1. U. S. Nuclear Regulatory Commission (NRC) Order EA-03-009, "Issuance of Order Establishing Interim Inspection Requirements for Reactor Pressure Vessel Heads at Pressurized Water Reactors,"
dated February 11, 2003
- 2. Letter from H. A. Sepp (Westinghouse) to the Document Control Desk (NRC) dated May 16, 2003;
Subject:
Request for Review and Approval Westinghouse Topical Report WCAP 15987-P,"Technical Basis for the Embedded Flaw Process for Repair of Reactor Vessel Head Penetrations" (Proprietary) and WCAP-15987-NP (Non-proprietary)
- 3. Letter from H. N. Berkow, (NRC) to H.A. Sepp, (Westinghouse) dated July 3, 2003;
Subject:
Acceptance for Referencing - Topical Report WCAP 15987-P, Revision 2, Technical Basis of the Embedded Flaw Process for Repair of Reactor Vessel Head Penetrations, (TAC No.
MB8997)"
- 4. Letter LTR-NRC-03-61 from J. S. Galembush (Westinghouse) to Terrence Chan (NRC) and Bryan Benney (NRC) dated October 1, 2003;
Subject:
Inspection of Embedded Flaw Repair of a J-groove Weld" 6of6