ML11164A133

Safety Evaluation of Relief Requests ISI-RR-02 Through ISI-RR-11, for the Fourth 10-Year Inservice Inspection Interval

ML11164A133
Person / Time
Site:	Hatch
Issue date:	07/15/2011
From:	Kulesa G Plant Licensing Branch II
To:	Ajluni M Southern Nuclear Operating Co
Boyle P, NRR/DORL/LPL2-1, 415-3936
References
TAC ME4218, TAC ME4219
Download: ML11164A133 (31)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 July 15, 2011 Mr. M. J. Ajluni Nuclear Licensing Director Southern Nuclear Operating Company, Inc.

40 Inverness Center Parkway Post Office Box 129S, Bin - 038 Birmingham, AL 3S201-129S

SUBJECT:

EDWIN I. HATCH NUCLEAR PLANT,UNIT NOS. 1 AND 2, TWO SEPARATE SAFETY EVALUATIONS FOR RELIEF REQUESTS (RR) INSERVICE INSPECTION (ISI)-RR-02 THROUGH ISI-RR-11, FOR THE FOURTH 10-YEAR INSERVICE INSPECTION (lSI) INTERVAL (TAC NOS. ME4218 AND ME4219)

Dear Mr. Ajluni:

By letter to the U.S. Nuclear Regulatory Commission (NRC), dated July 8,2010 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML 101890S72), as supplemented by letters dated November 23, 2010 (ADAMS Accession No. ML103280372), and March 22, 2011 (ADAMS Accession No. ML110820261), Southern Nuclear Operating Company, Inc. (the licensee), submitted Relief Request (RR) ISI-RR-02 (Edwin I. Hatch Nuclear Plant, Unit 1 (HNP-1>>, ISI-RR-03 (HNP-1 and Edwin I. Hatch Nuclear Plant, Unit 2 (HNP-2>>,

ISI-RR-04 (HNP-2), ISI-RR-OS (HNP-2), ISI-RR-06 (HNP-2), ISI-RR-07 (HNP-1), ISI-RR-08 (HNP-2), ISI-RR-09 (HNP-2), ISI-RR-10 (HNP-2), and ISI-RR-11 (HNP-1 and HNP-2) from certain requirements of the American Society of Mechanical Engineers, Boiler and Pressure Vessel Code (ASME Code), under the provisions of Title 10 of the Code of Federal Regulations (10 CFR), Part SO, paragraph SO.SSa(g)(S)(iv). Subsequently by letter dated April 27, 2011 (ADAMS Accession No. ML111170439), relief request RR-ISI-04 (HNP-2) was withdrawn.

Based on the review of the information the licensee provided, the NRC staff concludes that the specified requirements are impractical and would create a burden on the licensee without a compensating increase in the level of quality and safety. Therefore, the licensee's requested reliefs are authorized in accordance with 1 0 CFR 10 SO.SSa(g)(6)(i). Granting of reliefs pursuant to 10 CFR SO.SSa(g)(6)(i) is authorized by law and will not endanger life or property or the common defense and security, and is otherwise in the public interest giving due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility.

All other ASME Code,Section XI, requirements, for which relief was not specifically requested and authorized herein by the NRC staff, remain applicable, including third-party review by the Authorized Nuclear Inservice Inspector.

M. Ajluni

- 2 The NRC Safety Evaluations are enclosed. If you have any questions concerning this matter, please contact Patrick Boyle at (301) 415-3936.

Sincerely, Ii;

-:44711t)/L:e:;.-J oRa1<'~~sa, thief Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-321 and 50-366

Enclosures:

1. Safety Evaluation One

2. Safety Evaluation Two cc w/encls: Distribution via Listserv

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION ONE BY THE OFFICE OF NUCLEAR REACTOR REGULATION FOURTH 10-YEAR INSERVICE INSPECTION INTERVAL RELIEF REQUESTS ISI-RR-03, ISI-RR-04, ISI-RR-05, ISI-RR-08, ISI-RR-09, ISI-RR-10, AND ISI-RR-11 SOUTHERN NUCLEAR OPERATING COMPANY, INC.

EDWIN I. HATCH NUCLEAR PLANT, UNIT NOS. 1 AND 2 DOCKET NOS. 50-321 AND 50-366

1.0 INTRODUCTION

By letter dated July 8,2010, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML101890572), Southern Nuclear Operating Company, Inc. (SNC, the licensee), requested relief from the requirements of the American Society of Mechanical Engineers, Boiler and Pressure Vessel Code (ASME Code) for its Fourth 10-Year Interval Inservice Inspection (lSI) Program. Specifically, the licensee proposed lSI Program Relief Requests (RR) ISI-RR-03, ISI-RR-04, ISI-RR-05, ISI-RR-08, ISI-RR-09, ISI-RR-10, and ISI-RR 11 for Edwin I. Hatch Nuclear Plant, Unit Nos. 1 and 2 (HNP-1 and HNP-2). Additionally, in response to Nuclear Regulatory Commission (NRC) requests for additional information (RAI),

the licensee submitted further information in letters dated November 23,2010, (ADAMS Accession No. ML1032803720), and March 22, 2011 (ADAMS Accession No. ML110820261 ).

SNC withdrew ISI-RR-04 in its letter of April 27. 2011 (ADAMS Accession No. ML111170439).

2.0 REGULATORY REQUIREMENTS lSI of the ASME Code Class 1, 2, and 3 components is to be performed in accordance with Section XI of the ASME Code, and applicable addenda, as required by Title 10 of the Code of Federal Regulations (10 CFR), Part 50, paragraph 50.55a(g), except where specific relief has been granted by the Commission pursuant to 10 CFR 50.55a(g)(6)(i). In addition, 10 CFR 50.55a(a)(3) states that alternatives to the requirements of paragraph (g) may be used, when authorized by the NRC, if the licensee demonstrates that (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.

Pursuant to 10 CFR 50.55a(g)(4), ASME Code Class 1,2, and 3 components (including supports) shall meet the requirements, except the design and access provisions and the preservice examination requirements, set forth in the ASME Code,Section XI, to the extent practical within the limitations of design, geometry, and materials of construction of the

- 2 components. The regulations require that inservice examination of components and system pressure tests conducted during the first 10-year interval and subsequent intervals comply with the requirements in the latest edition and addenda of Section XI of the ASME Code, which was incorporated by reference in 10 CFR 50.55a(b) twelve months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein. The ASME Code of record for HNP 1 and 2 is the 2001 Edition through the 2003 Addenda of Section XI of the ASME Code. In addition, as required by 10 CFR 50.55a, the ASME Code,Section XI, 2001 Edition was used for Appendix VIII, Performance Demonstration for Ultrasonic Examination Systems. The proposed relief is sought for the fourth 10-year lSI interval which began on January 1, 2006 and ends on December 31,2015.

3.0 EVALUATION The information provided by the licensee in support of the request for relief from ASME Code requirements has been evaluated and the bases for disposition are documented below. For clarity, the licensee's request has been evaluated in several parts according to ASME Code,Section XI, Examination Category.

3.1 Relief Request ISI-RR-03, ASME Code,Section XI, Examination Category 8-J, Item 89.11, Pressure Retaining Welds in Stainless Steel Piping NPS [Nominal Pipe Size] 4 or Larger Circumferential Welds (HNP-1 and HNP-2)

ASME Code Requirement ASME Code,Section XI, Table IW8-2500-1, Examination Category 8-J, Item 89.11 requires that essentially 100 percent ofthe weld length be examined by the volumetric and surface methods.

ASME Code Case N-460, as an alternative approved for use by the NRC in RG 1.147, Revision 16 (ADAMS Accession No. ML101800536) states that a reduction in examination coverage due to part geometry or interference for the ASME Code Class 1 and 2 weld is acceptable provided that the reduction is less than 10 percent, i.e., greater than 90-percent examination coverage is obtained.

ASME Code Case N-663, as an alternative for use by NRC RG 1.147, Revision 16, states that in lieu of the surface examination requirements for the piping welds of Examination Category 8-F (NPS4 and larger), 8-J (NPS 4 and larger), C-F-1, and C-F-2, surface examinations may be limited to areas identified by the Owner as susceptible to outside surface attack.

licensee's ASME Code Relief Request In accordance with 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the ASME Code-required 100-percent volumetric examination for the following Class 1 piping welds:

-3 Table 3.1.1 - ASME Code,Section XI, Examination Category B-J

• Item Weld Number System Description Coverage 89.11 1G31-'1 RWCUM-6-D-20 Reactor Water Cleanup System 316NG Elbow to Valve 50 percent 89.11 2831-1 RCM-28AD-3 Reactor Circulation System Valve to 316NG Elbow 50 percent I 89.11 2E11-1 RHRM-24A-13 Residual Heat Removal System 316NG Elbow to 316NG Tee 85.6 percent Licensee's 8asis for Relief Request (as stated)

The examination limitations for the above welds are due to the design of components (e.g., valves and tees) which restricts the access for the ultrasonic examinations shown in [Table 3.1.1 above]. With one exception, the examinations are a one-side examination and it would be impractical to increase the coverage.

Compliance [with the ASME Code requirements] would require the replacement of the valves and tees with new components fabricated with a special design to allow examination.

Per the NRC staff position located in Generic Letter 88-01, these welds are considered resistant to Intergranular Stress Corrosion Cracking (lGSCC) and are defined as Category A. Each weld was stress improved using the induction heating stress improvement (IHSI) or Mechanical Stress Improvement Process (MSIP) and are all protected by effective hydrogen water chemistry except for 2E11-1 RHRM-24A-13, which is not considered to be protected due to stagnant conditions. The ultrasonic examination performed from at least one side of the weld in conjunction with the resistant materials, the stress improvement, and the hydrogen protection provides reasonable assurance that unacceptable flaws have not developed in the subject weld or that they will be detected and repaired prior to the return of service. Therefore, based on the UT [ultrasonic]

examination of the subject areas to the maximum extent practical, there is reasonable assurance of the structural integrity and safety of the welds because the information and data obtained from the volume examined provided sufficient information to judge the overall integrity of the welds.

Furthermore, a VT-2 visual examination on the subject welds are [sic] [is]

performed each refueling outage as part of the leakage test. During operation, leakage can be determined by the leakage detection system (LDS) located in the Drywell. The LDS is described in HNP-1 FSAR [Final Safety Analysis Report]

Section 4.10 and HNP-2 FSAR Section 4.10. 8ased on the above information, relief should be granted per 10 CFR 50.55a(g)(6)(i).

Licensee's Proposed Alternative Examination None. The licensee did not propose any alternatives to the ASME Code requirements.

However, the licensee examined the subject welds to the extent practical.

-4 Staff's Evaluation The ASME Code requires essentially 100-percent volumetric and surface examination for selected Examination Category 8-J pressure retaining welds in piping. However, complete volumetric examinations are restricted by several factors including valve and tee configurations. These conditions preclude the licensee from obtaining full volumetric examinations of these welds. Gaining access for examination would require the replacement of the valves and tees with new components fabricated with a special design to allow examination. Imposition of this requirement would create a burden on the licensee; therefore, the ASME Code-required-100 percent volumetric examinations are considered impractical.

As shown on the sketches and technical descriptions included in the licensee's submittals, examinations of the subject welds have been performed to the extent practical with the licensee obtaining volumetric coverage ranging from SO to 8S.6 percent (see Table 3.1.1 above). Scan limitations in the axial and circumferential directions were caused by the surface angles on the various components. No indications were identified as a result of the Code-required examinations.

For weld 1G31-1 RWCUM-6-0-20, the licensee stated that coverage was limited to a one-sided examination due to the proximity of the valve taper to the weld.

Circumferential flaw coverage was obtained using 4S-degree and 70-degree shear waves. Axial flaw coverage using 4S-degree shear waves was limited to the elbow side.

Pursuant to the requirements of 10 CFR SO.SSa(b)(2)(xv)(A)(2) coverage is SO percent.

This weld was stress-improved during the 1993 outage using the MSIP process.

For weld 2831-1 RCM-28AO-3, the licensee stated that coverage was limited to a one-sided examination due to the proximity of the valve taper to the weld.

Circumferential flaw coverage was obtained using 4S-degree and 60-degree shear waves and 60-degree refracted longitudinal waves. Axial flaw coverage with 4S-degree shear waves was limited to the elbow side. Pursuant to the requirements of 10 CFR SO.SSa(b)(2)(xv)(A)(2) coverage is SO percent. This weld was stress-improved during the 1984 outage IJsing the IHSI process.

Lastly, for weld 2E11-1 RHRM-24A-13, the licensee stated that coverage was limited due to the tee configuration. One hundred percent coverage was obtained for axial flaws on both sides of the weld. On the elbow side, 1 OO-percent coverage for circumferential flaws was obtained. Coverage on the tee side for circumferential flaws was limited to S7 percent. Circumferential flaw coverage was obtained using 4S-degree and 60-degree refracted longitudinal waves. Axial coverage was obtained with 4S-degree shear waves.

As shown in table 3.1.1, the total Code-required coverage for this weld was 8S.6 percent. This weld was stress-improved during the 1984 outage using the IHSI process.

The licensee noted in their response to the NRC's RAI that Code Case N-663 was applicable to the components of this request as no areas in Examination Category 8-J were identified as susceptible to outside surface attack using the provisions described in Code Case N-663. Therefore, no surface examinations were performed on these components.

- S-The licensee has shown that it is impractical to meet the ASME Code-required volumetric examination coverage for the subject piping welds due to the geometry configuration of the welds. Considering the volumetric coverage obtained, it is reasonable to conclude that if significant service-induced degradation had occurred in the subject welds, evidence of it would have been detected. Furthermore, the staff determined that the examinations performed to the extent practical on the subject welds, along with consideration of the resistant materials, the stress improvement performed using either MSIP or IHSI and the application of hydrogen water chemistry (except for weld 2E 11-1 RHRM-24A-13), provide reasonable assurance of structural integrity of the subject welds. Additionally, the subject welds undergo a VT-2 visual examination each refueling outage as part of the leakage test, and during operation, leakage can be determined by the leakage detection system located in the Drywell. These measures provide additional assurance that the structural integrity of the subject welds continues to be maintained.

3.2 Relief Request ISI-RR-04, ASME Code,Section XI, Examination Category 8-J, Item 89.11, Dissimilar Metal Pressure Retaining Welds In Piping NPS 4 or Larger Circumferential Welds (HNP-2)

ASME Code Requirement ASME Code,Section XI, Table IW8-2S00-1, Examination Category 8-J, Item 89.11 requires that essentially 100 percent of the weld length be examined by the volumetric and surface methods. Note: This weld is a Category 8-J dissimilar metal weld that was examined pursuant to Supplement 10 of Appendix VIII.

ASME Code Case N-460, as an alternative approved for use by the NRC in RG 1.147, Revision 16 states that a reduction in examination coverage due to part geometry or interference for the ASME Code Class 1 and 2 weld is acceptable provided that the reduction is less than 10 percent, i.e., greater than 90-percent examination coverage is obtained.

ASME Code Case N-663, as an alternative for use by the NRC RG 1.147, Revision 16, states that in lieu of the surface examination requirements for the piping welds of Examination Category 8-F (NPS4 and larger), 8-J (NPS 4 and larger), C-F-1, and C-F-2, surface examinations may be limited to areas identified by the Owner as susceptible to outside surface attack.

Licensee's ASME Code Relief Request In accordance with 10 CFR SO.SSa(g)(S)(iii), the licensee requested relief from the ASME Code-required 1 OO-percent volumetric examination for the Weld 2821-'1 FW 12M-B, which is a Class 1 piping weld, Category 8-J, Item 89.11, Dissimilar Metal Weld in the Feed Water System. This weld connects a carbon steel pipe to an Inconel extension piece using Inconel weld material.

- 6 Licensee's Basis for Relief Request (as stated)

... This Inconel [182] weld joins a carbon steel pipe to an Inconel [600 safe end]

extension piece. On the Inconel side of the weld, there is a weld overlay which extends to the edge of the weld. On the carbon steel side, there is a severe taper.

This weld had mechanical stress improvement process (MSIP) performed on it in 1994 which mitigated the potential for stress corrosion cracking (SCC). With the SCC mitigation and the high level of coverage for circumferential flaws (with at least one beam angle), there is reasonable assurance that unacceptable flaws have not developed in the subject weld or that they will be detected and repaired prior to the return of service. Therefore, based on the UT examination of the subject area to the maximum extent practical, there is reasonable assurance of the structural integrity and safety of the weld because the information and data obtained from the volume examined provided sufficient information to judge the overall integrity of the weld.

Furthermore, a VT-2 visual examination on the subject weld is performed each refueling outage as part of the leakage test. During operation leakage can be determined by the leakage detection system (LDS) located in the Drywell. The LDS is described in HNP-2 FSAR Section 4.10. Therefore, relief should be granted per 10 CFRSO.SSa(g)(6)(i).

Licensee's Proposed Alternative Examination None. The licensee did not propose any alternatives to the ASME Code requirements.

However, the licensee examined the subject welds to the extent practical.

Staff's Evaluation The ASME Code requires essentially 1 ~O-percent volumetric and surface examination for selected Examination Category B-J pressure retaining welds in piping. However, complete volumetric examination of this weld is restricted by the component configuration of a weld overlay extending to the edge of the weld on one side and a severe taper on the other side of the weld. These conditions preclude the licensee from obtaining a full volumetric examination of this weld. The licensee stated that an automated phased array system was used to maximize the examination coverage; however composite Code coverage of the weld was only 30 percent.

Obtaining more coverage would require the replacement of the feedwater nozzle safe-end and associated thermal sleeve to eliminate the overlay obstruction or alternately the overlay would need to be extended over Weld 2B21-1 FW-12AA-8. No indications were identified as a result of the Code-required examinations.

As shown on the sketches and technical descriptions included in the licensee's submittals, examinations of the subject weld have been performed to the extent practical with the licensee obtaining volumetric coverage of 30 percent. The licensee stated that circumferential flaw (transverse) exams were performed by utilizing beam angles of 3~-degree, 4S-degree, 60-degree, and 70-degree refracted longitudinal waves and by utilizing a 4S-degree shear wave for the carbon steel base material. These exams could only be performed from the upstream

- 7 side of the weld due to the weld overlay obstruction; in addition, this exam was limited due to the taper. The examination procedure required that when examining from only one side of the weld, that two beam angles were required to pass through the volume for calculating ASME Code credit. Only about 30 percent of the volume was covered by two beam angles and therefore received ASME Code credit. However, eighty-seven percent of the ASME Code required examination volume (lower 1/3rd of the volume) was examined for circumferential flaws with a minimum of one angle.

The licensee further stated that the axial flaw (parallel) examinations were performed utilizing 25-degree, 35-degree,45-degree, and 55-degree refracted longitudinal waves and by utilizing 35-degree, 45-degree, and 55-degree shear waves. These exams could only be performed from the upstream side of the weld due to the weld overlay obstruction. Only about 30 percent of the volume was covered due to the geometry.

The licensee noted in their response to the NRC's RAI that ASME Code Case N-663 was applicable to the component of this request as no areas in Examination Category 8 J were identified as susceptible to outside surface attack using the provisions described in ASME Code Case N-663. Therefore, no surface examination was performed on this weld.

The licensee has shown that it is impractical to meet the ASME Code-required volumetric examination coverage for the subject piping weld due to the configuration on either side of the weld. On the carbon steel side of the weld, the impracticality results from a severe taper. On the Inconel side of the weld, the impracticality results from the licensee's application of a weld overlay which extends to the edge of the weld. The NRC staff acknowledges that (1) the weld overlay was applied prior to the 10 CFR 50.55a mandated implementation of Appendix VIII, (2) the subject weld has been mitigated by the mechanical stress improvement process, (3) this weld undergoes a VT-2 visual examination each refueling outage as part of the leakage test, and (4) during operation, leakage can be determined by the leakage detection system located in the Drywell.

However, the significant lack of creditable coverage for the ASME Code-required Appendix VIII examinations as a result the overlay concerns the staff. As such, in their Request for Additional Information (RAI), the staff asked the licensee to discuss what plans are in place to increase the creditable coverage of this weld. In the licensee's RAI response, dated March 22, 2011, the licensee stated that "due to the significant lack of coverage for Appendix VIII examinations, this weld is scheduled to receive an overlay prior to the end of the 4th Inservice Inspection Interval which ends on December 31, 2015."

In light of their plan to overlay this weld before the end of the current (4th) lSI Interval, the licensee withdrew Relief Request ISI-RR-04 in their letter dated April 27, 2011. No further staff review is required at this time.

- 8 3.3 Relief Request ISI-RR-05, ASME Code,Section XI, Examination Category C-F-2, Item C5.51, Circumferential Pressure Retaining Welds in Carbon or Low Alloy Steel Piping (HNP-2)

ASME Code Requirement ASME Code,Section XI, Table IWC-2S00-1, Examination Category C-F-2, Item CS.S1 requires that 100 percent of each weld requiring examination receive a surface and volumetric exam.

ASME Code Case N-460, as an alternative approved for use by the NRC in RG 1.147, Revision 16 states that a reduction in examination coverage due to part geometry or interference for the ASME Code Class 1 and 2 weld is acceptable provided that the reduction is less than 10 percent, Le., greater than gO-percent examination coverage is obtained.

ASME Code Case N-663, as an alternative for use by the NRC RG 1.147, Revision 16, states that in lieu of the surface examination requirements for the piping welds of Examination Category B-F (NPS4 and larger), B-J (NPS 4 and larger), C-F-1, and C-F-2, surface examinations may be limited to areas identified by the Owner as susceptible to outside surface attack.

Licensee's ASME Code Relief Request In accordance with 10 CFR SO.SSa(g)(S)(iii), the licensee requested relieffrom the ASME Code-required 100-percent volumetric examination for the Weld 2E41-2HPCI-16 TS-18 Elbow to Tee Weld, which is a Class 2, Category C-F-2, Item CS.S1, Circumferential Pressure Retaining Weld in Carbon or Low Alloy Steel Piping in the High Pressure Coolant Injection System.

Licensee's Basis for Relief Request (as stated)

A volumetric examination was performed on the weld for eighty percent coverage. In addition, VT-2 visual examinations associated with the Class 2 leakage test are performed each inspection period for the weld, 2E41-2HPCI-16-TS-18. Therefore.

based on the UT examination along with the VT-2 examination of the subject area to the maximum extent practical, there is reasonable assurance of the structural integrity and safety of the weld because the information and data obtained from the volume examined provided sufficient information to judge the overall integrity of the weld.

Licensee's Proposed Alternative Examination None. The licensee did not propose any alternatives to the ASME Code requirements.

However, the licensee examined the subject welds to the extent practical.

- 9 Staff's Evaluation The ASME Code requires essentially 1 DO-percent volumetric and surface examination for selected Examination Category C-F-2 pressure retaining welds in piping. However, complete volumetric examination of this weld is restricted to a single side exam from the elbow side due to a machined taper on the tee. As shown on the sketches and technical descriptions included in the licensee's submittal, examinations of the subject weld have been performed to the extent practical with the licensee obtaining volumetric coverage of 80 percent. Obtaining more coverage would require the re-design of the tee to allow access from the tee side or for the weld crown to be leveled. Imposition of this requirement would create a burden on the licensee; therefore, the ASME Code-required 1~O-percent volumetric examinations are considered impractical.

Scans for circumferential flaws were performed using 45-degree and 70-degree shear waves from the elbow side. Scans for axial flaws were not required for this carbon steel weld as footnote 7 for Examination Category C-F-2 only requires volumetric examination in the axial direction when longitudinal welds intersect the circumferential weld. In their RAI, the staff asked the licensee to confirm that no longitudinal weld intersects this circumferential weld and how this was determined. The licensee stated that, though seamless piping was used, the ultrasonic procedure implemented, which was based on PDI-UT-1, includes clockwise and counter-clockwise scans to detect axially oriented flaw indications. As such, axial flaw coverage was obtained using 45-degree shear wave search units. No indications were identified as a result of the Code-required examinations.

The licensee noted in their response to the NRC's RAI that Code Case N-663 was applicable to the component of this request, and using the provisions described in Code Case N-663, no areas in Examination Category C-F-2 were identified as susceptible to outside surface attack. Therefore, no surface examination was performed on this weld.

The licensee has shown that it is impractical to meet the ASME Code-required volumetric examination coverage for the subject piping weld due to the tee configuration of the component. Considering the coverage obtained, it is reasonable to conclude that if Significant service-induced degradation had occurred in the subject weld, evidence of it would have been detected. Furthermore, the staff determined that the examinations performed to the extent practical on the subject weld provide reasonable assurance of structural integrity of the subject weld.

3.4 Relief Request ISI-RR-08, ASME Code,Section XI. Examination Category 8-J, Item 89.11! Dissimilar Metal Pressure Retaining Welds Piping NPS 4 or Larger Circumferential Welds (HNP-2)

ASME Code Requirement ASME Code,Section XI, Table IW8-2500-1, Examination Category 8-J, Item 89.11 requires that essentially 100 percent of the weld length be examined by the volumetric and surface methods.

-10 ASME Code Case N-460, as an alternative approved for use by the NRC in RG 1.147, Revision 16 states that a reduction in examination coverage due to part geometry or interference for the ASME Code Class 1 and 2 weld is acceptable provided that the reduction is less than 10 percent, i.e., greater than 90-percent examination coverage is obtained.

ASME Code Case N-663, as an alternative for use by the NRC RG 1.147, Revision 16, states that in lieu of the surface examination requirements for the piping welds of Examination Category 8-F (NPS4 and larger), 8-J (NPS 4 and larger), C-F-1, and C-F-2, surface examinations may be limited to areas identified by the Owner as susceptible to outside surface attack.

Licensee's ASME Code Relief Request In accordance with 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the ASME Code-required 100-percent volumetric examination for the Weld 2E11-1 RHRM 20RS-3, which is a Class 1 piping weld, Category 8-J, Item 89.11, Dissimilar Metal Weld in the Residual Heat Removal System. This is a stainless steel elbow to carbon steel pipe weld.

Licensee's 8asis for Relief Request (as stated)

Although the ultrasonic examination was limited for axially-oriented flaws the circumferential flaw coverage of the weld joint was scanned from both sides with both the 45° RL transducer and the 60° RL transducer for 100% coverage. This coverage provides assurance that unacceptable flaws have not developed in the subject weld or that they will be detected and repaired prior to the return of service. Therefore, based on the UT examination of the subject area to the maximum extent practical, there is reasonable assurance of the structural integrity and safety of the weld because the information and data obtained from the volume examined provided sufficient information to judge the overall integrity of the weld.

Furthermore, a VT-2 visual examination on the subject welds is performed each refueling outage as part of the leakage test. During operation leakage can be determined by the leakage detection system (LDS) located in the Drywell. The LDS is described in HNP-2 FSAR Section 4.10. Based on the above information, relief should be granted per 10CFR50.55a(g)(6)(i).

Licensee's Proposed Alternative Examination None. The licensee did not propose any alternatives to the ASME Code requirements.

However, the licensee examined the subject welds to the extent practical.

Staffs Evaluation The ASME Code requires essentially 100- percent volumetric and surface examinations for selected Examination Category 8-J pressure retaining welds in piping. However, complete volumetric examination of this weld is limited due to a taper created by the

- 11 difference in the outside diameter of the elbow versus the outside diameter of the pipe.

This configuration precludes the licensee from obtaining a full volumetric examination of this weld. Obtaining more coverage would require the replacement of the elbows with new components fabricated with a special design to allow inspection. Imposition of this requirement would create a burden on the licensee; therefore, the ASME Code-required 1 DO-percent volumetric examinations are considered impractical. No indications were identified as a result of the ASME Code-required examinations.

As shown on the sketches and technical descriptions included in the licensee's submittals, examinations of the subject weld have been performed to the extent practical with the licensee obtaining aggregate volumetric coverage of 87 percent. The licensee stated that circumferentially oriented flaw coverage was obtained from both the upstream and downstream sides of the weld by utilizing beam angles of 45-degree and 60-degree refracted longitudinal waves with 1 DO-percent code coverage. The base material was examined by utilizing 45-degree shear waves with 1 DO-percent coverage.

For axially oriented flaw coverage, the examinations were performed utilizing 45-degree refracted longitudinal waves from both the downstream and upstream side of the weld with 61-percent Code coverage.

The licensee noted in their response to the NRC's RAI that ASME Code Case N-663 was applicable to the component of this request as no areas in Examination Category 8-J were identified as susceptible to outside surface attack using the provisions described in ASME Code Case N-663. Therefore, no surface examination was performed on this weld.

The licensee has shown that it is impractical to meet the ASME Code-required volumetric examination coverage for the subject piping weld due to the taper created by the difference in the outside diameter of the elbow versus the outside diameter of the pipe. Considering the coverage obtained, it is reasonable to conclude that if significant service-induced degradation had occurred in the subject weld, evidence of it would have been detected. Furthermore, the staff determined that the examinations performed to the extent practical on the subject weld provide reasonable assurance of structural integrity of the subject weld. Additionally, the subject welds undergo a VT-2 visual examination each refueling outage as part of the leakage test, and during operation, leakage can be determined by the leakage detection system located in the Drywell.

These measures provide additional assurance that the structural integrity of the subject welds continues to be maintained.

3.5 Relief Request ISI-RR-09, ASME Code,Section XI. Examination Category 8-J, Item 89.11, Pressure Retaining Welds in Piping NPS 4 or Larger Circumferential Welds HNP-2 ASME Code Requirement ASME Code,Section XI, Table IW8-2500-1, Examination Category 8-J, Item 89.11 requires that essentially 100 percent of the weld length be examined by the volumetric and surface methods.

- 12 ASME Code Case N-460, as an alternative approved for use by the NRC in RG 1.147, Revision 16 states that a reduction in examination coverage due to part geometry or interference for the ASME Code Class 1 and 2 weld is acceptable provided that the reduction is less than 10 percent, i.e., greater than 90-percent examination coverage is obtained.

ASME Code Case N-663, as an alternative for use by the NRC RG 1.147, Revision 16, states that in lieu of the surface examination requirements for the piping welds of Examination Category B-F (NPS4 and larger), B-J (NPS 4 and larger), C-F-1, and C-F-2, surface examinations may be limited to areas identified by the Owner as susceptible to outside surface attack.

Licensee's ASME Code Relief Request In accordance with 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the ASME Code-required 1 OO-percent volumetric examination for the Weld 2B21-1 FW 12BC-12, which is a Class 1 piping weld, Category B-J, Item B9.11, Pressure Retaining Weld in Piping NPS 4 or Larger Circumferential Weld. This is an Inconel weld joining an Inconel safe end to Inconel safe end extension.

Licensee's Basis for Relief Request (as stated)

Although the ultrasonic examination was limited for axially-oriented flaws, the circumferential flaw coverage of the weld joint was scanned from both sides for 100%

coverage. This 86.5% composite coverage along with 100% circumferential flaw coverage provides reasonable assurance that unacceptable flaws have not developed in the subject weld or that they will be detected and repaired prior to the return of service. Therefore, based on the UT examination of the subject area to the maximum extent practical, there is reasonable assurance of the structural integrity and safety of the weld because the information and data obtained from the volume examined provided sufficient information to judge the overall integrity of the weld.

Furthermore, a VT-2 visual examination on the subject welds is performed each refueling outage as part of the leakage test. During operation leakage can be determined by the leakage detection system (LOS) located in the Drywell. The LOS is described in HNP-2 FSAR Section 4.10. Based on the above information, relief should be granted per 10CFR50.55a(g)(6)(i).

Licensee's Proposed Alternative Examination None. The licensee did not propose any alternatives to the ASME Code requirements.

However, the licensee examined the subject welds to the extent practical.

Staff's Evaluation The ASME Code requires essentially 100-percent volumetric and surface examination for selected Examination Category B-J pressure retaining welds in piping. However, complete volumetric examination of this weld is limited due to a taper on the downstream piping. This configuration precludes the licensee from obtaining a full volumetric

- 13 examination of this weld. Obtaining more coverage would require the replacement of the tapered piping with new piping fabricated with a special design to allow inspection.

Imposition of this requirement would create a burden on the licensee; therefore, the ASME Code-required 1 OO-percent volumetric examinations are considered impractical.

No indications were identified as a result of the ASME Code-required examinations.

As shown on the sketches and technical descriptions included in the licensee's submittals, examinations of the subject weld have been performed to the extent practical with the licensee obtaining aggregate volumetric coverage of 86.5 percent. The licensee stated that circumferentially oriented flaw coverage was obtained from both the upstream and downstream sides of the weld by utilizing beam angles of 30-degree, 45-degree, 60-degree and 70-degree refracted longitudinal waves along with 45-degree shear waves for 100-percent code coverage. For axially oriented flaw coverage, the examinations were performed utilizing 25-degree, 35-degree, 45-degree and 55-degree refracted longitudinal waves and 35-degree, 45-degree, and 55-degree shear waves.

Downstream axially oriented flaw examinations were limited due to the safe end configuration; the Code coverage for axial flaws was 73 percent.

The licensee noted in their response to the NRC's RAI that ASME Code Case N-663 was applicable to the component of this request as no areas in Examination Category 8-J were identified as susceptible to outside surface attack using the provisions described in ASME Code Case N-663. Therefore, no surface examination was performed on this weld.

The licensee has shown that it is impractical to meet the ASME Code-required volumetric examination coverage for the subject piping weld due to the taper on the downstream piping. Considering the coverage obtained, and considering the licensee's performance of ultrasonic techniques employed to maximize this coverage, it is reasonable to conclude that if significant service-induced degradation had occurred in the subject weld, evidence of it would have been detected. Furthermore, the staff determined that the examinations performed to the extent practical on the subject weld provide reasonable assurance of structural integrity of the subject weld. Additionally, the subject welds undergo a VT-2 visual examination each refueling outage as part of the leakage test, and during operation, leakage can be determined by the leakage detection system located in the Drywell. These measures provide additional assurance that the structural integrity of the subject welds continues to be maintained.

3.6 Relief Request ISI-RR-10. ASME Code,Section XI, Examination Category 8-F. Item 85.10. Pressure Retaining Dissimilar Metal Welds in Vessel Nozzle-to-Safe End Welds NPS 4 or Larger (HNP-2)

ASME Code Requirement ASME Code,Section XI, Table IW8-2500-1, Examination Category 8-F, Item 85.10 requires that essentially 100 percent of the weld length be examined by the volumetric and surface methods.

ASME Code Case N-460, as an alternative approved for use by the NRC in RG 1.147, Revision 16 states that a reduction in examination coverage due to part geometry or

- 14 interference for the ASME Code Class 1 and 2 weld is acceptable provided that the reduction is less than 10 percent, i.e., greater than gO-percent examination coverage is obtained.

ASME Code Case N-663, as an alternative for use by the NRC in RG 1.147, Revision 16, states that in lieu of the surface examination requirements for the piping welds of Examination Category B-F (NPS4 and larger), B-J (NPS 4 and larger), C-F-1, and C-F-2, surface examinations may be limited to areas identified by the Owner as susceptible to outside surface attack.

Licensee's ASME Code Relief Request In accordance with 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the ASME Code-required 100-percent volumetric examination for Weld 2E21-1CS-10A-21 and Weld 2E21-1 CS-1 OB-20, which are Class 1 piping welds, Category B-F, Item B5.1 0, Pressure Retaining Dissimilar Metal Welds in the Core Spray System. These dissimilar metal welds join low alloy steel safe ends to Inconel buttered nozzles.

Licensee's Basis for Relief Request (as stated)

Although the ultrasonic examination was limited for axially-oriented flaws, the circumferential flaw coverage of the weld joint was scanned from both sides for 100%

coverage. This provides reasonable assurance that unacceptable flaws have not developed in the subject weld or that they will be detected and repaired prior to the return of service. Therefore, based on the UT examination of the subject areas to the maximum extent practical, there is reasonable assurance of the structural integrity and safety of the welds because the information and data obtained from the volume examined provided sufficient information to judge the overall integrity of the welds.

Furthermore, a VT-2 visual examination on the subject welds is performed each refueling outage as part of the leakage test. During operation leakage can be determined by the leakage detection system (LOS) located in the Drywell. The LOS is described in HNP-2 FSAR Section 4.10. Based on the above information, relief should be granted per 10CFR50.55a(g)(6)(i).

Licensee's Proposed Alternative Examination None. The licensee did not propose any alternatives to the ASME Code requirements.

However, the licensee examined the subject welds to the extent practical.

Staff's Evaluation The ASME Code requires essentially 1 OO-percent volumetric and surface examination for selected Examination Category B-F pressure retaining dissimilar metal welds.

However, complete volumetric examination of this weld is limited due to weld shrinkage at the weld toe. This configuration precludes the licensee from obtaining a full volumetric examination of this weld. Obtaining more coverage would require the weld to receive an overlay, or to be replaced or have additional material added to the weld shrinkage at the weld toe. Imposition of this requirement would create a burden on the

-15 licensee; therefore, the ASME Code-required 100-percent volumetric examinations are considered impractical.

As shown on the sketches and technical descriptions included in the licensee's submittals, examinations of the subject weld have been performed to the extent practical with the licensee obtaining aggregate volumetric coverage of 86.5 percent. The licensee stated that circumferentially oriented flaw coverage was obtained from both the upstream and downstream sides of the weld by utilizing beam angles of 30-degree, 45-degree, 60-degree and 70-degree refracted longitudinal waves along with 45-degree shear waves for 100-percent code coverage. For axially oriented flaw coverage, the examinations were performed utilizing 25-degree, 35-degree, 45-degree and 55-degree refracted longitudinal waves and 35-degree, 45-degree, and 55-degree shear waves.

Downstream axially oriented flaw examinations were limited due to the safe end configuration; the ASME Code coverage for axial flaws was 73 percent.

By letter dated November 23, 2010, the licensee stated that two subsurface, circumferentially oriented, planar flaws were detected in Weld 2E21-1CS-10A-21. The flaws were acceptable in accordance with ASME Code Table IWB-3514-2. Additionally, one subsurface, circumferentially oriented, planar flaw was detected in weld 2E21-1 CS 10B-20. The flaw was acceptable in accordance with ASME Code Table IWB-3514-2.

By letter dated February 23, 2011, the staff asked the licensee to clarify how they determined that these circumferentially oriented flaws were subsurface. By letter dated March 22, 2011, the licensee explained that prior to the examination of these welds, the weld crowns were removed and the only examination interference was from shrinkage at the downstream toe of the welds. The licensee's review of the data sheets indicated that there was no interference during the examination of the welds for circumferentially oriented flaws. The licensee further explained that the automated phased array display clearly showed that no flaws were closer than %" to the inside surface. Therefore, the licensee determined that the circumferentially oriented indications were determined to be subsurface.

The licensee noted in their response to the NRC's RAJ that ASME Code Case N-663 was applicable to the component of this request as no areas in Examination Category B-J were identified as susceptible to outside surface attack using the provisions described in ASME Code Case N-663. Therefore, no surface examination was performed on this weld.

The licensee has shown that it is impractical to meet the ASME Code-required volumetric examination coverage for the subject piping weld due to the weld shrinkage at the weld toe. Based on the volumetric coverage obtained for the subject welds, and considering the licensee's performance of ultrasonic techniques employed to maximize this coverage, it is reasonable to conclude that if significant service-induced degradation had occurred, evidence of it would have been detected by the examinations that were performed. Furthermore, the staff determined that the examinations performed provide reasonable assurance of structural integrity of the subject welds. Additionally, the subject welds undergo a VT-2 visual examination each refueling outage as part of the leakage test, and during operation, leakage can be determined by the leakage detection system located in the Drywell. These measures provide additional assurance that the structural integrity of the subject welds continues to be maintained.

- 16 3.7 Relief Reguest ISI-RR-11, ASME Code,Section XI, Examination Category 8-J, Item 89.11, Pressure Retaining Welds in Piping NPS 4 or Larger Circumferential Welds (HNP-1 and HNP-2)

ASME Code Reguirement ASME Code,Section XI, Table IW8-2500-1, Examination Category 8-J, Item 89.11 requires that essentially 100 percent of the weld length be examined by the volumetric and surface methods.

ASME Code Case N-460, as an alternative approved for use by the NRC in RG 1.147, Revision 16 states that a reduction in examination coverage due to part geometry or interference for the ASME Code Class 1 and 2 weld is acceptable provided that the reduction is less than 10 percent, i.e., greater than 90-percent examination coverage is obtained.

ASME Code Case N-663, as an alternative for use by the NRC RG 1.147, Revision 16, states that in lieu of the surface examination requirements for the piping welds of Examination Category 8-F (NPS4 and larger), 8-J (NPS 4 and larger), C-F-1, and C-F-2, surface examinations may be limited to areas identified by the Owner as susceptible to outside surface attack.

Licensee's ASME Code Relief Reguest In accordance with 10 CFR 50.55a{g){5)(iii), the licensee requested relief from the ASME Code-required 100-percent volumetric examination the following Class 1 piping welds:

Table 3.7.1 -ASME Code,Section XI, Examination Category B-J Item Weld Number System Description Coverage 89.11 1831-1 RC-128R-A-1 Reactor Reci rculation System 304 Pipe to 304 Sweepolet 50 percent 89.11 2G31-1 RWCUM-6-D-15 Reactor Water Cleanup System 316NG Pipe to Penetration 50 percent 89.11 12G31-1RWCUM-6-D-16 Reactor Water Cleanup System 316NG Pipe to Valve 50 percent 89.11 2G31-1 RWCUM-6-D-17 Reactor Water Valve to Cleanup System tion 50 percent Licensee's 8asis for Relief Request (as stated)

Per the NRC staff position located in Generic Letter 88-01 these welds are considered susceptible to Intergranular Stress Corrosion Cracking (IGSCC), but the IGCSS was mitigated by stress improvement after more than two cycles of operation. These welds are defined as Category C. Each weld was stress improved using the induction heating stress improvement (lHSI) and are all protected by effective hydrogen water chemistry. The ultrasonic examination

- 17 performed from at least one side of the weld in conjunction with the stress improvement and the hydrogen protections should provide reasonable assurance that unacceptable flaws have not developed in the subject weld or that they will be detected and repaired prior to the return of service. Therefore, based on the UT examination of the subject areas to the maximum extent practical, there is reasonable assurance of the structural integrity and safety of the welds because the information and data obtained from the volume examined provided sufficient information to judge the overall integrity of the welds.

Furthermore, a VT-2 visual examination on the subject welds [is] performed each refueling outage as part of the leakage test. During operation leakage can be determined by the leakage detection system (LDS) located in the Drywell. The LDS is described in HNP-1 FSAR Section 4.10 and HNP-2 FSAR Section 4.10.

Based on the above information, relief should be granted per 10CFR50.55a(g)(6)(i).

Licensee's Proposed Alternative Examination None. The licensee did not propose any alternatives to the ASME Code requirements.

However, the licensee examined the subject welds to the extent practical.

Staff's Evaluation The ASME Code requires essentially 100-percent volumetric and surface examination for selected Examination Category B-J pressure retaining welds in piping. However, complete volumetric examination of this weld is limited due to the design of the components which restricts access for the ultrasonic examinations. The configurations preclude the licensee from obtaining a full volumetric examination of the welds shown above in Table 3.7.1. Obtaining more coverage would require the replacement of the existing valves, and tees with new components fabricated with a special design to allow examination. Imposition of this requirement would create a burden on the licensee; therefore, the ASME Code-required 100-percent volumetric examinations are considered impractical. No indications were identified as a result of the Code-required examinations.

As shown on the sketches and technical descriptions included in the licensee's submittals, examinations of the subject weld have been performed to the extent practical with the licensee obtaining aggregate volumetric coverage of 50 percent for each weld.

For Weld 1 B31-1 RC-12BR-A-1, coverage was limited to a one-sided examination due to the proximity of the sweepolet taper to the weld. Axial flaw coverage with 45-degree shear waves was limited to the pipe side. Circumferential flaw coverage was obtained using 45-degree and 60-degree shear waves and 60-degree refracted longitudinal waves. Using a single V-path, the 60-degree search units interrogated the pipe side of the examination volume, the weld root area, and a small portion of the examination volume on the sweepolet side. Pursuant to the requirements of 10 CFR 50.55a(b)(2)(xv)(A)(2) full-coverage credit from a single side cannot be claimed until a successful single-sided Appendix VIII demonstration is performed. Therefore, even

- 18 though more than SO percent of the volume was examined, ASME Code coverage is given as SO percent. This weld was stress-improved in 1985 using the IHSI process.

For Weld 2G31-1RWCUM-6-D-1S, coverage was limited to a one-sided examination due to the proximity of the penetration taper to the weld. Axial flaw coverage with 4S-degree shear waves was limited to the pipe side. Skewing of the transducer was used to increase the coverage for the axial flaw coverage; however, the additional volume gained by skewing was not credited as it is difficult to quantify. Circumferential flaw coverage was obtained using 4S-degree and 70-degree shear waves. Though additional coverage of the examination volume on the tapered side of the weld was obtained from the pipe side of the weld, this is considered a "best effort" unqualified examination technique. Pursuant to the requirements of 10 CFR SO.SSa(b)(2)(xv)(A)(2) full-coverage credit from a single side cannot be claimed until a successful single-sided Appendix VIII demonstration is performed. Therefore, even though more than SO percent of the volume was examined, ASME Code coverage is given as SO percent. This weld was stress-improved during the 1984 outage using the IHSI process.

For Weld 2G31-1RWCUM-6-D-16, coverage was limited to a one-sided examination due to the proximity of the valve taper to the weld. Additionally, the valve is a cast material, and currently, no qualified Appendix VIII supplement is available for cast material. Axial flaw coverage with 4S-degree shear waves was limited to the pipe side. Skewing of the transducer was used to increase the coverage for the axial flaw coverage; however, the additional volume gained by skewing was not credited as it is difficult to quantify.

Circumferential flaw coverage was obtained by the use of 4S-degree and 70-degree shear waves. Though additional coverage of the examination volume on the tapered side of the weld was obtained from the pipe side of the weld, this is considered a "best effort" unqualified examination technique. Pursuant to the requirements of 10 CFR SO.SSa(b)(2)(xv)(A)(2) full-coverage credit from a single side cannot be claimed until a successful single-sided Appendix VIII demonstration is performed. Therefore, even though more than SO percent of the volume was examined, Code coverage is given as SO percent. This weld was stress-improved during the 1984 outage using the IHSI process.

For Weld 2G31-1RWCUM-6-D-17, Coverage was limited to a one-sided examination due to the proximity of the valve taper to the weld. Axial flaw coverage with 4S-degree shear waves was limited to the penetration side. Circumferential flaw coverage was obtained by the use of 4S-degree and 70-degree shear waves. Though additional coverage of the examination volume on the tapered side of the weld was obtained from the penetration side of the weld, this is considered a "best effort" unqualified examination technique. Pursuant to the requirements of 10 CFR SO.SSa(b)(2)(xv)(A)(2) fUll-coverage credit from a single side cannot be claimed until a successful single-sided Appendix VIII demonstration is performed. Therefore, even though more than SO percent of the volume was examined, Code coverage is given as SO percent. This weld was stress improved during the 1984 outage using the IHSI process.

The licensee noted in their response to the NRC's RAI that ASME Code Case N-663 was applicable to the component of this request as no areas in Examination Category 8-J were identified as susceptible to outside surface attack using the provisions

- 19 described in ASME Code Case N-663. Therefore, no surface examination was performed on this weld.

The licensee has shown that it is impractical to meet the ASME Code-required volumetric examination coverage for the subject piping weld due to the design of the components which restricts access for the ultrasonic examinations. Considering the coverage obtained, and considering the licensee's performance of ultrasonic techniques employed to maximize this coverage, it is reasonable to conclude that if significant service-induced degradation had occurred in the subject weld, evidence of it would have been detected. Furthermore, the staff determined that the examinations performed to the extent practical on the subject weld provide reasonable assurance of structural integrity of the subject weld. Additionally, the subject welds undergo a VT-2 visual examination each refueling outage as part of the leakage test, and during operation, leakage can be determined by the leakage detection system (LOS) located in the Orywell. These measures provide additional assurance that the structural integrity of the subject welds continues to be maintained.

4.0 CONCLUSION

S The staff has reviewed the licensee's submittal and concludes that ASME Code examination coverage requirements are impractical for the subject welds listed in Relief Requests ISI-RR-07 for Unit 1, ISI-RR-05, -06, -08, -09, and -10 for Unit 2 and ISI-RR-03 and -11 for both Units 1 and 2. Furthermore, imposition of these ASME Code requirements would create a burden on the licensee. The staff further determined that based on the volumetric coverage obtained on the subject welds, it is reasonable to conclude that if significant service-induced degradation had occurred, evidence of it would have been detected by the examinations that were performed. Furthermore, the staff concluded that examinations performed to the extent practical provide reasonable assurance of structural integrity of the subject welds.

Accordingly, the NRC staff concludes that the licensee has adequately addressed all of the regulatory requirements set forth in 10 CFR 50.55a(g)(6)(i), and is in compliance with the Code of Federal Regulations' requirements for the granting of relief. Therefore, the NRC staff grants relief for the subject examinations of the components contained in Relief Requests ISI-RR-07 for Unit 1, ISI-RR-05, -06, -08, -09, and -10 for Unit 2 and ISI-RR-03 and -11 for both Units 1 and 2.

The staff has further determined that granting Relief Request ISI-RR-03, ISI-RR-05, ISI-RR-08, ISI-RR-09, ISI-RR-10, and ISI-RR-11 pursuant to 10 CFR 50.55a(g)(6)(i) is authorized by law and will not endanger life or property, or the common defense and security, and is otherwise in the public interest giving due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility.

Additionally, the staff reviewed the licensee's submittal for the subject weld listed in Relief Request ISI-RR-04 for Unit 2. However, as stated in their letter dated March 22, 2011, the licensee plans to overlay this weld before the end of the current (fourth) lSI Interval. As such, by letter dated April 27, 2011, the licensee withdrew Relief Request ISI-RR-04 for HNP-2.

- 20 All other ASME Code,Section XI requirements for which relief was not specifically requested and approved in the subject relief requests remain applicable, including third-party review by the Authorized Nuclear Inservice Inspector.

Principle Contributor: Carol Nove Date: July 15, 2011

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION TWO BY THE OFFICE OF NUCLEAR REACTOR REGULATION FOURTH 10-YEAR INSERVICE INSPECTION INTERVAL RELIEF REQUESTS ISI-RR-02, ISI-RR-06 AND ISI-RR-07 SOUTHERN NUCLEAR OPERATING COMPANY, INC.

EDWIN I. HATCH NUCLEAR PLANT, UNIT NOS. 1 AND 2 DOCKET NOS. SO-321 AND SO-366

1.0 INTRODUCTION

By letter dated July 8, 2010 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML 101890S72), Southern Nuclear Operating Company, Inc.

(the licensee), requested relief from the requirements of the American Society of Mechanical Engineering, Boiler and Pressure Vessel Code (ASME Code), for its Fourth 10-Year Interval Inservice Inspection (lSI) Program. Specifically, the licensee proposed lSI Program Relief Requests (RR) ISI-RR-02 and ISI-RR-07 for Edwin I. Hatch Nuclear Plant, Unit No.1 (HNP-1) to reduce the inspection requirements for reactor pressure vessel (RPV) shell-to-flange weld and welded attachments for piping, and ISI-RR-06 would reduce the inspection requirements for the pressure retaining welds in pump casings for Edwin I. Hatch Nuclear Plant, Unit No. 1 (HNP-2). Additionally, in response to the Nuclear Regulatory Commission (NRC) staff's request for Additional information (RAI), the licensee submitted further information in a letter dated November 23,2010 (ADAMS Accession No. ML103280372).

2.0 REGULATORY EVALUATION

lSI of the ASME Code Class 1, 2, and 3 components is performed in accordance with Section XI of the ASME Code and applicable addenda as a way to detect degradation to ensure that the structural integrity of these components will be maintained. This is required by 10 CFR SO.SSa{g), except where specific relief has been granted by the Commission pursuant to 10 CFR SO.SSa{g){6){i). Paragraph SO.SSa{a){3) states that alternatives to the requirements of paragraph (g) may be used, when authorized by the NRC, if: (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.

For the RPV shell-to-flange weld (ASME Code,Section XI, Category B-A, Item Number B1.30),

welded attachments for piping (Category B-K, Item Number B1 0.20), and the pressure retaining welds in pump casings (Category C-G, Item Number C6.1 0), ASME Code,Section XI requires

- 2 100-percent inspection during each 10-year lSI interval. For the last two types of weld where ASME Code Case N-460, "Alternative Examination Coverage for Class 1 and Class 2 Welds,"

apply, examination coverage of 90 percent is permitted if full coverage cannot be obtained due to part geometry or interference.

Applications similar to Relief Requests ISI-RR-02 for the RPV shell-to-flange weld and ISI-RR-07 for the welded attachments for piping have been approved for the third lSI interval for HNP-1 in 2007.

3.0 TECHNICAL EVALUATION

3.1 Relief Request ISI-RR-02 (HNP-1) 3.1.1 Licensee's Evaluation Component(s) for Which an Alternative is Requested (As Stated)

[ASME Code,Section XI, Table IWB-2500-1,] Category B-A, Item Number B1.30

[RPV] shell-to-flange weld.

'I B11/C Low Alloy Steel - Inspected 02/25/2006.

The [UT] examinations could only be performed from the shell side of the weld because of the weld and nozzle taper as shown in Figures 1 [1] and 2[2]. [UT]

examinations from tapered surfaces have not been qualified by the Performance Demonstration Initiative (POI).

ASME Code Requirement for Which an Alternative is Requested (As Stated)

Examination Category B-A, Table IWB-2500-1 of the 2001 Edition with 2003 addenda of the ASME [Code, Section XI] requires a volumetric examination be performed on this weld. The examination volume is shown in ASME [Code,] Section XI Figure IWB-2500-4 and includes essentially 100 percent of the weld length. The examinations were performed from the outside of the [RPV] using manual examination procedures, personnel, and equipment qualified in accordance with

[ASME Code,Section XI,] Appendix VIII, Supplements 4 and 6, as amended by the conditions set forth in 10 CFR 50.55a. The use of Appendix VIII was allowed by alternative ISI-AL T-01, which was approved by NRC safety evaluation [(SE)] dated January 3, 2006.

Licensee's Proposed Alternative Examination (As Stated)

The composite UT [ultrasonic testing] examination coverage was calculated as 68.7 percent by examination personnel. Limitations and coverage for specific types of examinations is discussed below.

-3 Circumferential Flaws Examinations from the shell side scanning for circumferential flaws, using the 60° Refracted Longitudinal (RL), (designated as 60° T on Figure 1 [1]) had a composite coverage of 79.4 percent.... The composite coverage scanning for circumferential flaws with the thermocouple restrictions was calculated as 77.4 percent.

Axial Flaws Examinations from the shell side scanning for axial flaws, using the 60° [RL],

(designated as 60° P on Figure 2[21) had a composite coverage of about 50.4 percent.... The composite coverage scanning for axial flaws (including the thermocouple restrictions) was calculated as 49 percent.

Licensee's Bases for Alternative To appreciably increase the examination volume coverage of Weld C-1 would require a redesign of the RPV flange, which would be an undue burden. Therefore, it is concluded that meeting the ASME Code requirement is impractical.

A significant volume of the weld was examined and no unacceptable indications were found. Coverage for circumferential flaws originating at the inside surface or middle of the examination volume was in excess of 90 percent. Additionally, the

[RV] vertical welds and the [RPV accessible] bottom head welds were examined using [ASME Code,Section XI,] Appendix VIII techniques without any unacceptable indications; therefore, it is unlikely that any pattern of degradation exists in the [RV]

that has gone undetected.... Therefore, based on the UT examination of the subject area to the maximum extent practical, there is reasonable assurance of the structural integrity of the weld because the information and data obtained from the volume examined provided sufficient information to judge the overall integrity of the weld.....

Period of application The proposed alternative is applicable for the 4th [lSI] Interval, extending from January 1, 2006 through December 31, 2015.

3.1.2 Staff's Evaluation The ASME Code requires 1 OO-percent volumetric examination each inspection interval of the RPV shell-to-flange weld classified under ASME Code,Section XI, Table IWB-2500-1, Examination Category B-A, Item B1.30. As discussed in the licensee's descriptions, the examinations of the subject weld were limited by the configuration of the RPV shell-to-f1ange Cl This refers to Figure 1 in Enclosure 1 regarding ISI-RR-02 from the licensee's July 8, 2010, submittal.

Figure 1 is not included in this SE.

[£] This refers to Figure 2 in Enclosure 1 regarding ISI-RR-02 from the licensee's July 8, 2010, submittal.

Figure 2 is not included in this SE.

-4 weld. For the licensee to achieve 1 OO-percent volumetric coverage, the RPV flange would have to be redesigned and modified. This would place a burden on the licensee, and, therefore, the ASME Code-required 1 OO-percent volumetric examinations are considered impractical.

The licensee was able to examine approximately 68.7 percent of the required examination volume for both axial and circumferential flaws. Examinations were performed from the shell side of the weld. For circumferential flaws, the composite coverage is 77.4 percent. Since the RPV shell-to-flange weld is circumferential, if a flaw existed, it was more likely to be a circumferential flaw. This postulation is consistent with Appendix G, "Fracture Toughness Criteria for Protection against Failure," of the ASME Code,Section XI, where only a circumferential flaw is postulated for the RPV beltline circumferential weld. Hence, the most meaningful coverage, i.e., the lSI information most important to structural integrity, that was achieved by the licensee for this application is 77.4 percent. Further, the examinations performed by the licensee did not detect any unacceptable indications, and there has not been any industry history of failures for the RPV shell-to-flange weld.

Therefore, the staff determined that the proposed inspection still provides reasonable assurance of structural integrity of the RPV shell-to-flange weld because there are no plant-specific and industry history of RPV shell-to-flange weld failures; there is reasonable assurance that evidence of service-induced degradation, if existed, would have been detected by the examinations that were performed; and VT-2 visual examinations are performed each refueling outage to detect leakage.

3.2 Relief Request ISI-RR-06 (HNP-2) 3.2.1 Licensee's Evaluation Component(s) for Which an Alternative is Requested (As Stated)

[ASME Code,Section XI, Table IWC-2500-1, Examination] Category C-G, Item C6.10, Pressure Retaining Welds in Pump Casings:

2E11-2RHR-PMI-A - Residual Heat Removal (RHR) Pump A Inlet Nozzle - Carbon Steel - Inspected 02/28/2009.

2E21-2CS-PMI-A - Core Spray (CS) Circumferential Pump A Inlet Nozzle Weld Carbon Steel - Inspected 02/28/2009.

ASME Code Requirement for Which an Alternative is Requested (As Stated)

[ASME Code,] Section XI, Table IWC-2500-1, Examination Category C-G, Item C6.10 requires that 100 percent welds in all components in each piping run examined under Examination Category C-F receive a surface examination. In case of multiple pumps of similar design, size, function, and service in a system, required weld examinations may be limited to all the welds in one pump in the same group or distributed among any of the pumps of the same group.

ASME Code Case N-460, as an alternative for use by the NRC RG 1.147, Revision 15, ["Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1,"]

- 5 states that a reduction in examination coverage due to part geometry or interference for the ASME Class 1 or 2 weld is acceptable provided that the reduction is less that

[sic] [than] 10 percent, i.e., greater than 90 percent examination coverage is obtained.

Licensee's Proposed Alternative Examination (As Stated)

Coverage was limited for the surface examinations due to the proximity of concrete walls to the welds (Figure 1[3]), 2E11-2RHR-PMI-A and 2E21-2CS-PMI-A. Surface examination coverage was calculated to be 60 percent for 2E11-2RHR-PMI-A and 54 percent for 2E21-2CS-PMI-A. Supplemental visual coverage was performed on each weld to achieve coverage of greater than 90 percent.

Licensee's Bases for Alternative (As Stated)

Coverage was limited for the surface examinations due to the proximity of concrete walls to the welds (Figure 1[3]), 2E11-2RHR-PMI-A and 2E21-2CS-PMI-A....

Increasing the surface examination coverage would require a redesign of the pumps and room to allow for additional space around the weld.

Supplemental visual coverage was performed to increase the amount of coverage to greater than 90 percent. Furthermore, SNC will ensure there is no leakage coming from the area of the subject nozzle during the Leakage TesUHydrostatic Test which is performed each period.... Therefore, based on the surface examination along with the VT-2 examination of the subject areas to the maximum extent practical, there is reasonable assurance of the structural integrity and safety of the welds because the information and data obtained from the area examined provided sufficient information to judge the overall integrity of the welds....

Period of application (As Stated)

The proposed alternative is applicable for the 4th [lSI] Interval, extending from January 1, 2006 through December 31, 2015.

3.2.2 Staff's Evaluation The ASME Code requires 1 OO-percent surface examination each inspection interval of the pressure retaining welds in pump casings classified under ASME Code,Section XI, Table IWC-2500-1, Examination Category C-G, Item C6.1 O. As discussed in the licensee's descriptions the examinations, of the subject weld, were limited by the adjacent concrete walls.

However, since the relief request states that this is the first relief request for these welds, the staff issued RAI-1, asking how the ASME Code-required coverage was achieved in previous examinations. The licensee replied in its November 23, 2010, response to the staff's RAI that the third interval coverage of 91 percent for RHR pump A and core spray pump A was over

[3] This refers to Figure 1 in Enclosure 5 regarding ISI-RR-06 from the licensee's July 8, 2010, submittal.

Figure 1 is not included in this SE.

-6 estimated and it has been documented in the plant's corrective action program. The second interval coverage for RHR pump A for which a relief request was granted in 1998 was, however, 61 percent, and no relevant indications were recorded from both examinations. Considering that similar techniques were used and similar restrictions existed for all past examinations, the staff determined that the current coverage of 61 percent, which is consistent with the coverage reported for the second interval, is likely to be correct. Further, imposing the requirement would be impractical to the licensee because increasing the surface examination coverage would require a redesign of the pumps and room to allow for additional space around the weld.

The November 23,2010, response to RAI-2 provided additional information regarding the supplemental visual coverage to complement the surface examination. This information revealed that direct VT-1 examinations were performed in accordance with the ASME Code,Section XI requirements of IWA-2210, "Visual Examinations," using Level II personnel to supplement the limited magnetic particle examinations. Response to RAI-3 confirmed that industry operational experience, including SNC's fleet, showed no degradation in similar pressure retaining welds in pump casings. Hence, the staff determined that the proposed inspection still provides reasonable assurance of structural integrity of the subject pressure retaining welds in pump casings because no relevant indications were detected during past plant-specific and industry examinations; there is reasonable assurance that unacceptable flaws, if existed, would have been detected by the examinations that were performed; supplemental VT-1 examinations were performed to increase the amount of coverage to more than 90 percent, and VT-2 examinations were performed each period to detect leakage.

3.3 Relief Request ISI-RR-07 (HNP-1) 3.3.1 Licensee's Evaluation Component(s) for Which an Alternative is Requested (As Stated)

[ASME Code,Section XI, Table IWB-2500-1, Examination] Category B-K, Item B10.20, Welded Attachments for Piping.

1E41-1HPCI-10-D-7HL-8-1 and 2 - Carbon Steel-Inspected 02/28/2008.

ASME Code Requirement for Which an Alternative is Requested (As Stated)

[ASME Code,] Section XI, Table IW8-2500-1, Examination Category 8-K, Item 810.20 requires that essentially 100 percent of the length of the attachment weld on each attachment subject to examination be examined using the surface method.

ASME Code Case N-460, as an alternative for use by the NRC RG 1.147, Revision 15, states that a reduction in examination coverage due to part geometry or interference for the ASME Class 1 or 2 weld is acceptable provided that the reduction is less that 10 percent, i.e., greater than 90-percent examination coverage is obtained.

Licensee's Proposed Alternative Examination (As Stated)

... [Due to inaccessibility, three] sides of each lug were examined for a total of 54 percent coverage.....

- 7 Licensee's Bases for Alternative (As Stated)

The configuration consists of two lugs welded to the pressure retaining boundary with insufficient distance between them to perform a complete examination (Figure 1[41)....

Compliance would require replacement of the existing lugs with new lugs fabricated with a special design to allow examination.

The surface examination performed on three sides of each lug should provide assurance that unallowable flaws have not developed in the subject weld or that they will be detected and repaired prior to the return of service. Therefore, based on the surface examination of the subject areas to the maximum extent practical, there is reasonable assurance of the structural integrity and safety of the welds because the information and data obtained from the surface examined provided sufficient information to judge the overall integrity of the welds.

Furthermore, a VT-2 visual examination on the subject weld is performed each refueling outage as part of the leakage test. During operation, leakage can be determined by the leakage detection system (LOS) located in the Drywell. The LOS is described in [Hatch, Unit 1 Final Safety Analysis Report,] Section 4.10.

Period of application (As Stated)

The proposed alternative is applicable for the 4th [lSI] Interval, extending from January 1, 2006 through December 31, 2015.

3.3.2 Staff's Evaluation The ASME Code requires 100-percent surface examination each inspection interval of the welded attachments for piping classified under ASME Code,Section XI, Table IWB-2500-1, Examination Category B-K, Item B10.20. As discussed in the licensee's descriptions, insufficient distance between the two subject welds caused the examination coverage of these welds to be 54 percent. For the licensee to achieve 1 OO-percent coverage of the welded attachments would require replacement of the existing lugs with new lugs fabricated with a special design to allow examination. This would place a burden on the licensee, and, therefore, the ASME Code-required 1 OO-percent surface examinations are considered impractical.

The licensee was able to examine approximately 54 percent of the required examination area.

Further, the licensee's response to RAI-4 confirmed that past examinations performed by the licensee did not detect any unacceptable indications, and there has not been any industry history of failures for piping welded attachments..

Therefore, the staff determined that the proposed inspection still provides reasonable assurance of structural integrity of the subject welded attachments for piping because no relevant

~] This refers to Figure 1 in Enclosure 6 regarding ISI-RR-07 from the licensee's July 8, 2010, submittal.

Figure 1 is not included in this SE.

- 8 indications were detected during past plant-specific and industry examinations; there is reasonable assurance that unacceptable flaws, if existed, would have been detected by the examinations that were performed; and VT-2 examinations were performed each period to detect leakage.

4.0 CONCLUSION

Based on the review of the information in Enclosures 1, 5, and 6 of the submittal, including the burden caused by compliance, the examination coverage, the past plant-specific and industry examination results, and supplemental information provided by the VT-1 and VT-2 examinations, the staff finds that the ASME Code examination coverage requirements for ISI RR-02, ISI-RR-06, and ISI-RR-07 are impractical and that the licensee's proposed inspections provide reasonable assurance of structural integrity of the subject welds. Therefore, Relief Requests ISI-RR-02 and ISI-RR-07 for Unit 1 and ISI-RR-06 for Unit 2 are granted pursuant to 10 CFR 50.55a(g)(6)(i) for the fourth 1 O-year lSI interval. Granting of relief pursuant to 10 CFR 50.55a(g)(6)(i) is based on the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted incompliance with the Commission's regulations, and (3) the relief request approval will not be inimical to the common defense and security or to the health and safety of the public.

All other ASME Code,Section XI requirements for which relief was not specifically requested and approved in the subject requests for relief remain applicable, including third-party review by the Authorized Nuclear Inservice Inspector.

Principle Contributor: Simon Sheng Date: July 15, 2011

M. Ajluni

- 2 The NRC Safety Evaluations are enclosed. If you have any questions concerning this matter, please contact Patrick Boyle at (301) 415-3936.

Sincerely, IRA! by RMartin Acting for Gloria Kulesa, Chief Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-321 and 50-366

Enclosures:

1. Safety Evaluation One

2. Safety Evaluation Two cc w/encls: Distribution via Listserv DISTRIBUTION:

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