ML12199A233
| ML12199A233 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 07/19/2012 |
| From: | Nancy Salgado Plant Licensing Branch II |
| To: | Ajluni M Southern Nuclear Operating Co |
| References | |
| TAC ME8315, TAC ME8316, VEGP-ISI-ALT-07 | |
| Download: ML12199A233 (11) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 July 19, 2012 Mr. Mark J. Ajluni Manager, Nuclear Licensing Southern Nuclear Operating Company, Inc.
40 Inverness Center Parkway Post Office Box 1295, Bin -038 Birmingham, AL 35201-1295 SUB..IECT:
VOGTLE ELECTRIC GENERATING PLANT, UNITS 1 AND 2 - SAFETY EVALUATION OF RELIEF REQUESTVEGP-ISI-ALT-07, VERSION 1, FOR THE THIRD 10-YEAR INSERVICE INSPECTION INTERVAL, ALTERNATIVE REQUIREMENTS FOR EXAMINATION OF CONTROL ROD DRIVE MECHANISM PENETRATION NOZZLES (TAC NOS. ME8315AND ME8316)
Dear Mr. Ajluni:
By letter to the U.S. Nuclear Regulatory Commission (NRC), dated March 23, 2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12086A106), as supplemented by letter dated June 13, 2012 (ADAMS Accession No.ML12166A232), Southern Nuclear Operating Company, Inc. (SNC, the licensee) submitted relief request (RR) VEGP-ISI-AL T -07 from certain requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code) at the Vogtle Electric Generating Plant, Units 1 and 2 (Vogtle). Specifically, in accordance with Title 10 of the Code of Federal Regulations (10 CFR), Section 50.55a(a)(3)(ii), the licensee proposed an alternative for the examination of control rod drive mechanism penetration nozzles welded to the reactor pressure vessel upper head for Vogtle.
Based on the review of the information the licensee provided, the NRC staff determines that the proposed alternative provides reasonable assurance of structural integrity of the subject components and that complying with the requirement would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety. Accordingly, the NRC staff concludes that SNC has adequately addressed all of the regulatory requirements set forth in 10 CFR 50.55a(a)(3)(ii).
Therefore, the NRC staff authorizes the use of the proposed alternative in VEGP-ISI-AL T-07, Version 1.0 to define an alternate examination zone below the J-groove weld at Vogtle for the remainder of the third 10-Year Inservice Inspection interval.
All other requirements in ASME Code,Section XI, and 10 CFR 50.55a for which relief was not specifically requested and approved in this RR remain applicable, including third-party review by the Authorized Nuclear Inservice Inspector.
M. Ajluni
- 2 If you have any questions regarding this alternative inspection authorization, please contact Patrick Boyle, Project Manager for Vogtle at 301-415-3936.
Sincerely, 4"~~ -cV~
Nancy Sal§ado, Chief Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-424 and 50-425
Enclosure:
Safety Evaluation cc w/encl: Distribution via Listserv
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO INSERVICE INSPECTION ALTERNATIVE VEGP-ISI-AL T-07, VERSION 1.0 FOR EXAMINATION OF CONTROL ROD DRIVE MECHANISM PENETRATION NOZZLES SOUTHERN NUCLEAR OPERATING COMPANY, INC.
VOGTLE ELECTRIC GENERATING PLANT, UNITS 1 AND 2 DOCKET NOS. 50-424 AND 50-425
1.0 INTRODUCTION
By letter dated March 23, 2012, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12086A106) with supplement dated June 13, 2012 (ADAMS Accession No.ML12166A232) Southern Nuclear Operating Company (SNC, the licensee) requested authorization for an alternative to the inspection requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI, Code Case N-729-1 (N-729-1) "Alternative Examination Requirements for PWR [Pressurized Water Reactor] Reactor Vessel Upper Heads with Nozzles Having Pressure-Retaining Partial-Penetration WeldsSection XI, Division 1" as conditioned in Title 10 of Code of Federal Regulations (10 CFR), Section 50.55a(g)(6)(ii)(D) for the Vogtle Electric Generating Plant (Vogtle), Units 1 and 2.
Specifically, pursuant to 10 CFR 50.55a(a)(3)(ii), SNC requested to use the proposed alternative for the examination of control rod drive mechanism (CRDM) penetration nozzles welded to the reactor pressure vessel (RPV) upper head on the basis that complying with the specified requirement would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.
2.0 REGULATORY EVALUATION
Pursuant to 10 CFR 50.55a(a)(3)(ii), SNC proposed to use Inservice Inspection (lSI) Interval Alternative, VEGP-ISI-ALT-07, Version 1.0, to the requirements of N-729-1 as conditioned in 10 CFR 50.55a(g)(6)(ii)(D) which requires augmented lSI of RPV head penetration nozzles of PWRs in accordance with N-729-1 subject to the conditions specified in paragraphs (2) through (6) of 10 CFR 50.55a(g)(6)(ii)(D).
Section 50.55a(a)(3) of Title 10, states, in part, that alternatives to the requirements of 10 CFR 50.55a(g) may be used when authorized by the U.S. Nuclear Regulatory Commission (NRC) if the licensee demonstrates: (i) the proposed alternatives would provide an acceptable level of quality and safety, or (ii) compliance with the specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.
-2
3.0 TECHNICAL EVALUATION
3.1 ASME CODE COMPONENT(S) AFFECTED Code Class: 1 Item Number: B4.20
==
Description:==
UNS N06600 Nozzles and UNS N06082 or UNS W86182 partial penetration welds in reactor vessel head By letter dated June 13, 2012, SNC specified the following nozzles that require relieffrom the required examination coverage in N-729-1.
Incidence Angle s 30 degrees Required Coverage a = 1.5 inches Incidence Angle> 30 degrees Required Coverage a = 1.0 inches Vogtle Unit 1 2,5,9,14,15,18,19, and 21 63,64,65,66,67,68,69,72,73,74, 77, and 78 Vogtle Unit 2 None 75 and 77 3.2 APPLICABLE CODE EDITION AND ADDENDA The current Code of Record for Vogtle's, third 10-Year lSI interval is the ASME Section XI Code, 2001 Edition through the 2003 Addenda, as augmented by N-729-1, as amended and noticed in the Federal Register (73 FR 52730, September 10, 2008 and 76 FR 36232, June 21, 2011).
3.3 APPLICABLE CODE REQUIREMENT 10 CFR 50.55a(g)(6)(ii)(D)(1) requires that examinations of the reactor vessel head be performed in accordance with N-729-1 subject to the conditions specified in paragraphs 10 CFR 50.55a(g)(6)(ii){D)(2) through (6).
Paragraph 2500 of N-729-1 states, in part:.....If obstructions or limitations prevent examination of the volume or surface required by Fig. 2 for one or more nozzles, the analysis procedure of Appendix I shall be used to demonstrate the adequacy of the examination volume or surface for each such nozzle. If Appendix I is used, the evaluation shall be submitted to the regulatory authority having jurisdiction at the plant site..."
10 CFR 50.55a(g)(6)(ii)(D)(6) states that Appendix I of N-729-1 shall not be implemented without prior NRC approval.
Figure 2 in the N-729-1, as referenced by paragraph 2500, requires that the volumetric or surface examination coverage distance below the toe of the J-groove weld (dimension "a") be 1.5 inches for incidence angle, E, less than or equal to 30 degrees; 1 inch for incidence angle, E, greater than 30 degrees; or to the end of the tube, whichever is less. These coverage requirements are applicable to Vogtle, reactor vessel head penetrations.
- 3 3.4 REASON FOR REQUEST SNC stated that due to the physical configuration and limitations of the examination equipment associated with certain reactor head penetration nozzles, the full examination volume required by Table 1 of N-729-1 cannot be achieved for Item No. 84.20. The bottom end of both units reactor vessel head CRDM penetrations are externally (Le., outside diameter, or OD) threaded, internally (Le., inside diameter, or ID) tapered, and have an ultrasonic testing corner shadow zone produced by the thread relief. The shadow zone precludes ultrasonic or eddy current data acquisition in the lower nozzle area. For several of the penetrations, this geometric limitation reduces the lower coverage inspection distance from the bottom of the J-groove weld fillet to the top of the thread relief to a value less than the required coverage dimension "a" shown in Figure 2 of N-729-1.
As required by the NRC Order EA-03-009, SNC obtained examination coverage data on all 78 CRDM penetrations in each of the reactor vessel heads at Vogtle as shown in Tables 1 and 2 of the RR. SNC used this information to support its previous NRC Order Relaxation Requests regarding examination coverage below the J-groove weld. The NRC approved the Relaxation Requests of Order EA-03-009 on August 30,2006 (ADAMS Accession No. ML062360585).
However, the issuance of 10 CFR 50.55a(g)(6)(ii)(D) on September 10, 2008, requires implementation of N-729-1 with NRC conditions by December 31,2008. Once a licensee implemented the provisions of 10 CFR 50.55a(g)(6)(ii)(D), the Order and all previously approved relaxations were no longer applicable. In addition, 10 CFR 50.55a(g)(6)(ii)(D) was modified in the Final Rule issued on June 21, 2011.
The distance from the top of the thread relief to the bottom of the fillet of the J-groove weld, identified as "a" in Figure 2 of N-729-1, varies based on location of the penetration in the reactor vessel head. This distance is generally longer for penetrations at inboard locations and becomes progressively shorter for penetrations located farther away from the center of the reactor vessel head.
The design configurations at the bottom of the VEGP penetration nozzles included threaded sections, chamfered regions, and regions having a radius. The dimensional configuration at some nozzles is such that the inspectable distance from the lowest point at the toe of the J-groove weld to the bottom of the scanned region is less than the 1-inch lower boundary which does not satisfy the required coverage per N-729-1.
Tables 1 and 2 of the RR identified and highlighted penetrations with coverage lower than (Le.,
not satisfying) the requirements of N-729-1. SNC documented the results of these examinations in reports to the NRC after the Unit 1 outage in Fall 2006 (ADAMS Accession No. ML063600040) and the Unit 2 outage in Spring 2007 (ADAMS Accession No. ML071730265).
Using the Reinspection Year (RIY) equation in N-729-1, Paragraph 2410 (b), and a head temperature of 5600 F, the VEGP Unit 1 and Unit 2 time period for achieving 2.25 RIY is greater than every fourth refueling outage, and less than every fifth refueling outage. The examination frequency for VEGP Units 1 and 2 is therefore, every fourth refueling outage.
- 4 3.5 PROPOSED ALTERNATIVE AND BASIS FOR USE As an alternative to the volumetric and surface examination coverage requirements shown as dimension "a" in Figure 2 of N-729-1, SNC proposes the use of attainable ultrasonic examination distances shown in Tables 1 and 2 of the RR for those head penetrations listed in the above table in this safety evaluation. The anticipated examination coverage for the other head penetrations is expected to be met or exceeded dimension "a" in Figure 2 of N-729-1. In addition, SNC will examine the wetted surfaces on the vent line and vent line J-groove weld using the eddy current method as was done in the previous examinations performed under the NRC Order.
Appendix I of N-729-1 provides the analysis procedure for the evaluation of an alternative examination area or volume to that specified in Figure 2 of the Code Case if impediments prevent the examination of the complete zone. Section 1-1000 of N-729-1 requires that for alternative examination zones that could not achieve the N-729-1 examination zone below the J-groove weld, the analyses shall be performed using at least the stress analysis method (Section 1-2000) or the deterministic fraction mechanics analysis method (Section 1-3000) to demonstrate that the applicable criteria are satisfied.
3.5.1 Stress Analysis Section 1-2000 of N-729-1 requires that plant-specific analysis demonstrate that the hoop and axial stresses remain below 20 ksi (tensile) over the entire region outside the alternative examination zone but within the examination zone as defined in Figure 2 of N-729-1. SNC performed stress analyses in accordance with N-729-1 Section 1-2000 as documented in Westinghouse Report WCAP-16493-P, Revision 0, "Structural Integrity Evaluation of Reactor Vessel Upper Head Penetrations to Support Continued Operation: Vogtle Units 1 and 2," dated November 2005. By letter dated June 2, 2006 (ADAMS Accession No. ML061580121) SNC submitted WCAP-16493 to the NRC to support the examinations under the NRC Order.
Westinghouse performed for five different CRDM geometries, including the outermost row at odegrees angular position from the reactor vessel centerline, rows at 26.2 degrees, 44.3 degrees, 45.4 degrees and 48.7 degrees. Westinghouse calculated the distance below the J-groove weld that needs to be examined based on the point at which the CRDM penetration hoop stress distribution for the operating stress levels is less than 20 ksi tension. Westinghouse reviewed the WCAP recently and concluded that it is still applicable for the subject RR.
The hoop stress distribution plots, as shown in Figures 1 through 4 of the RR, indicated that the minimum achievable inspection coverage below the bottom of the J-groove weld ensures the stresses remain below 20 ksi (tensile) over the entire region outside the alternative examination zone but within the examination zone defined in Figure 2 as required by 1-2000 of N-729-1.
3.5.2 Deterministic Fracture Mechanics Analysis SNC used the hoop stress distributions to prepare the crack growth predictions to demonstrate that obtaining the examination coverage below the J-groove weld is sufficient to allow for a minimum of six effective full power years (EFPY) or four 18-month cycles between examinations. The crack growth predictions were based on a fracture mechanics analysis in accordance with N-729-1 Section 1-3200, Method 1. The fracture mechanics analysis resulted
- S in flaw tolerance charts which demonstrate that a potential axial crack in the unexamined zone will not grow to the toe of the J-groove weld prior to the required examination specified in Table 1 of N-729-1.
SNC stated that examination of portions of the nozzle significantly below the J-groove weld is not pertinent to the phenomena of concern, which include leakage through the J-groove weld and circumferential cracking in the nozzle above the J-groove weld. In each case, the proposed examination coverage is adequate to allow both Vogtle units to continue to operate prior to the hypothetical flaws reaching the J-groove weld. In accordance with 10 CFR SO.SSa(g)(6)(ii)(D) reqUirements, the next required examination would be completed prior to potential flaw propagation into the J-groove welds.
3.S.3 Surface Examination 10 CFR SO.SSa(g)(6)(ii)(D)(3) states in part that "if a surface examination is being substituted for a volumetric examination on a portion of a penetration nozzle that is below the toe of the J-groove weld, the sl.lrface examination shall be of the inside and outside wetted surface of the penetration nozzle not examined volumetrically."
SNC explained that to reduce personnel radiation exposure, the nozzles are typically inspected using remotely operated volumetric examination equipment. SNC further explained that although dye penetrant testing of threaded surfaces is possible, it is not practical. The threaded outside diameter (OD) makes a dye penetrant examination on the lower section of the penetration impractical because of excessive bleed-out from the threads. Eddy current examination would similarly not be effective due to the threaded configuration. In addition, radiation levels under the reactor vessel head have historically been observed in the range of 1 REM/hour to S REM/hour, contingent upon the Vogtle unit involved for the general area. If examinations were required to be performed, this would result in a condition contrary to the principle of ALARA (As Low As Reasonably Achievable). Therefore, SNC is not proposing surface examination alternative for those CRDM nozzles having only limited examination coverage below the J-groove weld.
3.6 DURATION OF PROPOSED ALTERNATIVE The duration of the proposed alternative is for the remainder of the third 10-Year lSI interval at Vogtle. These examinations are scheduled to be performed on Vogtle Unit 1 and Unit 2 during the Fall 2012 and Spring 2013 refueling outages, respectively, and every fourth refueling outage thereafter. The third 10-Yearinterval end date is May 30,2017.
3.7 NRC STAFF'S EVALUATION The NRC staffs review of the subject request was based on 10 CFR SO.SSa(a)(3)(ii) which allows alternatives to be used in lieu of requirements of 10 CFR SO.SSa if compliance with the specified requirements of 10 CFR SO.SSa would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.
-6 3.7.1 Alternative Examination Coverage Tables 1 and 2 of the RR provide the previous inspection coverage length obtained for CRDM nozzle penetrations in units 1 and 2, respectively. The NRC staff asked SNC to clarify the inspection lengths presented in Tables 1 and 2, including any measurement uncertainties and the specific nozzles covered under the RR.
By letter dated June 13, 2012, SNC responded that the limitations observed for the Unit-1 volumetric examinations are based on the additional chamfered/threaded regions. Figures RAI
- 1-1a and -1b in the June 13,2012, submittal portray the Unit-1 CRDM penetrations. The configuration on Unit-2 does not have the same limitation (except for nozzles 74 through 78).
SNC stated that the ultrasonic (UT) length measurement is performed in increments of 0.04 inches. The lengths referenced in Tables 1 and 2 of the RR do not address measurement uncertainty. SNC proposed that all nozzles within 0.04-inches of the N-729-1 required coverage length be included in the RR. Therefore, in addition to the thirteen CRDM penetrations presently shown in Table 3 of the RR, eight Unit 1 and one Unit 2 CRDM penetrations are being added to the list of nozzles that are covered under the RR.
Section 5.2 of the RR states that the flaw tolerance charts in Figures 5 through 8 demonstrates that a postulated through-wall flaw at the bottom edge of the proposed alternative examination zone will not grow to the toe of the J-groove weld.
By letter dated June 13, 2012, SNC responded that (a) Table RAI # 5-1 shows the alternative examination zone of the twenty-two Vogtle CRDM penetration nozzles included in the subject RR. The two sections of the table show the initial thirteen nozzles and the nine additional nozzles. The alternative examination zone extends from the toe of the weld down the nozzle for the dimension identified in Table RAI # 5-1, as noted in the column listing "a". This is the "a" dimension below the weld shown in Figures RAI # 1-1 a and RAI # 1-2 added to address RAI question # 1. (b) The as-built dimensions of the J-groove weld for the CRDM head penetrations where full examination coverage is not possible are shown in Table RAI # 5-1.
These tables include the L3 (elevation of the downhill weld toe) and L4 (the top or root of the downhill weld) as-built dimensions. The as-designed dimensions of the J-groove welds are shown in Table RAI # 5-2.
The staff finds that the additional nine nozzles added to the list of nozzles covered by the RR are acceptable because this will ensure in the future that the inspection length of these nine additional nozzles are acceptable by satisfying the requirements in the alternative.
3.7.2 Hardship The specific regulatory requirements for which relief is requested are defined in 10 CFR 50.55a(g)(6)(ii)(D)(3), which states, in part, that "...[i]nstead of the specified 'examination method' requirements for volumetric and surface examinations in Note 6 of Table 1 of N-729-1, the licensee shall perform volumetric and/or surface examination of essentially 100 percent of the required volume or equivalent surfaces of the nozzle tube, as identified by Figure 2 of N-729-1.."
SNC has provided evidence that a physical and radiological hardship would be incurred in order to be within compliance with the specified requirements. The NRC staff finds that a physical
- 7 hardship exists due to the inability of ultrasonic or eddy current inspection to effectively scan the bottom end of each CROM penetration as each nozzle is threaded on the outside diameter (00) and internally tapered. While dye penetrant inspection would be a possible option, the inspection would require manual application in a high radiation area. Therefore, the NRC staff finds that the radiological dose required to perform the additional surface examination would be a significant radiological hardship for the limited additional inspection coverage.
The NRC staff compared the regulatory requirements to the proposed alternative to ensure that, given this hardship, compliance with the regulations did not provide a compensating increase in the level of quality and safety. The NRC staff reviewed SNC's basis for the proposed alternative through a review of SNC's stress and fracture mechanics analysis.
3.7.3 Analyses SNC requested to use Mandatory Appendix I of N-729-1 in accordance with 10 CFR 50.55a(g)(6)(ii)(0)(6). Appendix I provides the analysis procedure for evaluation of an alternative examination area or volume if impediments prevent examination of the complete zone. SNC has performed, as required by Section 1-1000, a stress analysis for the subject penetrations and a deterministic fracture mechanics analysis to demonstrate that a potential axial crack in the unexamined zone will not grow to the toe of the J-groove weld prior to the examination frequency calculated in accordance with N-729-1.
In Section 5.1 of the RR, SNC stated that it recently reviewed WCAP16493-P and confirmed the report's continued applicability. By letter dated June 13, 2012, SNC stated that based on a review of the deterministic fracture mechanics analysis documented in WCAP-16493-P, the evaluation procedure used in generating the crack growth results shown in Figures 6-12 through 6-16 ofWCAP-16493-P is consistent with those discussed in Mandatory Appendix I paragraph 1-3200 of N-729-1. Therefore, the crack growth results in Figures 6-12 through 6-16 in WCAP 16493P are conservative.
SNC explained that since the future inspection interval is every four refueling outages or approximately six calendar years, Figures 6-12 through 6-16 in WCAP-16493-P remain applicable to use for seeking relaxation from the N-729-1 inspection coverage requirements below the J-groove weld. SNC proposed the alternative inspection coverage below the lowest point of the J-groove welds previously in letter dated May 18, 2006, titled "Vogtle Electric Generating Plant, Request for Relaxation of the First Revised Order (EA-03-009) Establishing Interim Inspection Requirements for Reactor Pressure Vessel Heads at Pressurized Water Reactors," (ADAMS Accession No. ML061390036). The NRC approved the alterative inspection coverage in a letter dated August 30, 2006 (ADAMS Accession No. ML062360585).
The NRC staff asked SNC to discuss whether the flaw evaluation in WCAP-16493-P, Revision ois based on the as-designed or as-built J-groove weld dimensions. By letter dated June 13, 2012, SNC stated that the flaw evaluation performed in WCAP-16493-P was based on the as designed J-groove weld dimensions. Westinghouse has performed a separate stress analysis using arbitrarily larger weld heights for the peripheral nozzles (48.7 -degree downhill side angle, 1.46-inch design dimension). The analysis cases included 1.46-inches, 2.35-inches, and 2.97 inches to determine their stress profiles. The 20 ksi criterion is reached in a shorter distance for the larger length welds; therefore, the 1.46-inch design value bounds the as-built dimensions of the CROM nozzles for the current analysis. The NRC staff notes that the issue
- 8 of as-designed vs. as-built length applies only to the stress analysis and not to the fracture mechanics analysis as the fracture mechanics analysis is based on actual measurements (i.e.,
as-built dimensions) of the inspectable length below the as-built weld toe obtained in previous inspections. The NRC staff finds that although WCAP-16493-P did not use the as-built J-groove weld dimensions, the stress analysis did use a dimension to bound the stress profiles of the as-built weld dimensions. Therefore, the stress profiles of the nozzle penetrations are acceptable.
The NRC staffs review of the stress analysis was based on the degradation phenomenon of concern being primary water stress corrosion cracking (PWSCC). PWSCC typically initiates in the areas of the high tensile stress in susceptible materials, such as alloy 600 materials, and propagates in response to time, adverse environment and stress intensity. Vogtle has a cold temperature head, which has slower PWSCC crack growth rates. In addition, based on SNC's stress analysis, SNC demonstrated that the areas of missed inspection coverage are less than 20 ksi which minimizes the initiation and propagation of PWSCC.
SNC's fracture mechanics analysis showed that a postulated through-wall axial flaw located at the bottom edge of the uninspected region of the nozzle would not grow to the toe of the J-groove weld, in this case the edge of the reactor coolant system pressure boundary, in less than every fourth refueling out~ge. The NRC staff finds the inspection area for each penetration nozzle to be adequate, because in all instances the time required for the postulated crack to grow the necessary distance to reach the toe of the J groove weld exceeds the time interval between inspections. Based on the information submitted, the NRC staff finds that the proposed inspection coverage and frequency provide reasonable assurance of structural integrity of each nozzle for which relief has been requested.
4.0 CONCLUSION
As set forth above, the NRC staff determines that the proposed alternative provides reasonable assurance of structural integrity of the subject components and that complying with the requirement would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety. Accordingly, the NRC staff concludes that SNC has adequately addressed all of the regulatory requirements set forth in 10 CFR SO.SSa(a)(3)(ii). Therefore, the NRC staff authorizes the use of the proposed alternative in VE-GP-ISI-ALT-07, Version 1.0 to define an alternate examination zone below the J-groove weld at Vogtle for the remainder of the third 10-year lSI interval.
All other requirements in ASME Code,Section XI, and 10 CFR SO.SSa for which relief was not specifically requested and approved in this RR remain applicable, including third-party review by the Authorized Nuclear Inservice Inspector.
Principal Contributor: John Tsao NRR/DE/EPNB Date of issuance: July 19, 2012
M. Ajluni
-2 If you have any questions regarding this alternative inspection authorization, please contact Patrick Boyle, Project Manager for Vogtle at 301-415-3936.
Sincerely, IRA!
Nancy Salgado, Chief Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-424 and 50-425
Enclosure:
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