ML16343A943

Brunswick Steam Electric Plant, Units 1 and 2 - Relief from the Requirements of the ASME Code Section Xi Inservice Inspection Requirements (Relief Request ISL-06) (CAC Nos. MF7494 and MF7495)

ML16343A943
Person / Time
Site:	Brunswick
Issue date:	02/27/2017
From:	Beasley B G Plant Licensing Branch II
To:	Gideon W R Duke Energy Progress
Hon A L, NRR/DORL/LPL2-2, 415-8480
References
CAC MF7494, CAC MF7495
Download: ML16343A943 (8)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 Mr. William R. Gideon Site Vice President Brunswick Steam Electric Plant 8470 River Rd. (M/C BNP001) Southport, NC 28461 February 27, 2017

SUBJECT:

BRUNSWICK STEAM ELECTRIC PLANT, UNITS 1 AND 2 -RELIEF FROM THE REQUIREMENTS OF THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS BOILER AND PRESSURE VESSEL CODE, SECTION XI INSERVICE INSPECTION REQUIREMENTS (RELIEF REQUEST ISl-06) (CAC NOS. MF7494 AND MF7495)

Dear Mr. Gideon:

By letter dated March 10, 2016 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML 16084A161), as supplemented by letter dated January 19, 2017 (ADAMS Accession No. ML 17019A242), Duke Energy Progress, LLC (the licensee) (formerly Duke Energy Progress, Inc.), requested U.S. Nuclear Regulatory Commission (NRC) approval of Relief Request (RR) ISl-06 for the fourth 10-year interval inservice inspection (ISi) program at Brunswick Steam Electric Plant (BSEP), Units 1 and 2. The licensee's RR ISl-06 addresses the examination coverage for certain pressure retaining welds in the peripheral control rod drive housings of the reactor pressure vessel, as required by the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (ASME Code). Specifically, pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(g)(5)(iii), the licensee requested relief and to use an alternative to the requirements of the ASME Code,Section XI for ISi items, on the basis that compliance with the ASME Code requirement is impractical due to plant design. The NRC staff has reviewed the subject request and concludes, as set forth in the enclosed safety evaluation, that the licensee has adequately addressed all of the regulatory requirements set forth in 1 O CFR 50.55a(g)(6)(i).

Accordingly, the NRC staff has determined that granting relief 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.

Therefore, the NRC grants relief for the subject examinations of the components contained in RR ISl-06 for BSEP Units 1 and 2 during the fourth 10-year ISi interval.

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 lnservice Inspector.

A. Pope If you have any questions, please contact the Project Manager, Andrew Hon at 301-415-8480 or via e-mail at Andrew.Hon@nrc.gov.

Docket Nos. 50-325 and 50-324

Enclosure:

Safety Evaluation cc w/encl: Distribution via Listserv Sincerely, Benjamin G. Beasley, Chief Plant Licensing Branch 11-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation W. Gideon

SUBJECT:

BRUNSWICK STEAM ELECTRIC PLANT, UNITS 1 AND 2 -RELIEF FROM THE REQUIREMENTS OF THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS BOILER AND PRESSURE VESSEL CODE, SECTION XI INSERVICE INSPECTION REQUIREMENTS (RELIEF REQUEST ISL-06) (CAC NOS. MF7494 AND MF7495) DATED FEBRUARY 27, 2017 DISTRIBUTION:

PUBLIC LPL2-2 R/F RidsACRS_MailCTR Resource RidsNrrDorlLpl2-2 Resource RidsNrrEpnb Resource RidsNrrLABClayton Resource RidsNrrPMBrunswick Resource RidsRgn2MailCenter Resource RKalikian, NRR JBowen, EDO Rll ADAMS A ccess1on N ML 16343A943 o.: OFFICE NRR/DORL/LPL2-2/PM NRR/DORL/LPL2-2/LA NRR/DE/EPNB/BC NAME AH on BClayton (PBlechman for) DAiiey* DATE 02/13/17 02/03/17 02/24/17 OFFICIAL RECORD COPY *b ., 1yema1 NRR/DORL/LPL2-2/BC BBeasley 02/27/16 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELIEF REQUEST NO ISl-06 REGARDING FOURTH 10-YEAR INSERVICE INSPECTION INTERVAL DUKE ENERGY PROGRESS.

LLC BRUNSWICK STEAM ELECTRIC PLANT. UNITS 1 AND 2 DOCKET NO. 50-325 AND 50-324

1.0 INTRODUCTION

By letter dated March 10, 2016 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML 16084A161), as supplemented by letter dated January 19, 2017 (ADAMS Accession No. ML 17019A242), Duke Energy Progress, LLC (formerly Duke Energy Progress, Inc. (Duke Energy, the licensee) requested U.S. Nuclear Regulatory Commission (NRC) approval of Relief Request (RR) ISl-06 for the fourth 10-year interval inservice inspection (ISi) program at the Brunswick Steam Electric Plant (BSEP), Units 1 and 2. The licensee's RR ISl-06 addresses the examination coverage for certain pressure retaining welds in the peripheral control rod drive (CRD) housings of the reactor pressure vessel, as required by the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (ASME Code). Specifically, pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(g)(5)(iii), "ISi program update: Notification of impractical ISi Code requirements," the licensee requested relief and to use an alternative to the requirements of the ASME Code,Section XI for ISi items, on the basis that compliance with the ASME Code requirement is impractical due to plant design.

2.0 REGULATORY EVALUATION

Pursuant to 10 CFR 50.55a(g), "lnservice inspection requirements,

ISi of the ASME Code, Class 1, 2, and 3, components is to be performed in accordance with the latest edition and addenda of Section XI of the ASME Code, except where specific relief has been granted by the Commission pursuant to 10 CFR 50.55a(g)(6)(i), "Impractical ISi requirements:

Granting of relief." Additionally, pursuant to 10 CFR 50.55a(g)(4), "lnservice inspection standards requirements for operating plants,

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, "Rules for lnservice Inspection of Nuclear Power Plant Components,

to the extent practical within the limitations of design, geometry, and materials of construction of the components.

The regulations require that inservice examination of components and system pressure tests Enclosure 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 incorporated by reference in 10 CFR 50.55a(a)(1

)(ii), 12 months prior to the start of the 120-month interval, subject to the conditions listed in 1 O CFR 50.55a(b). Section 50.55a(g)(5)(iii) of 10 CFR states, in part that, If the licensee has determined that conformance with a Code requirement is impractical for its facility the licensee must notify the NRC and submit, as specified in § 50.4, information to support the determinations.

Determinations of impracticality in accordance with this section must be based on the demonstrated limitations experienced when attempting to comply with the Code requirements during the inservice inspection interval for which the request is being submitted.

Requests for relief made in accordance with this section must be submitted

... no later than 12 months after ... the initial or subsequent 120-month inspection interval for which relief is sought. The fourth 10-year ISi interval for BSEP Units 1 and 2 began on May 11, 2008, and is scheduled to end on May 10, 2018. Section 50.55a(g)(6)(i) of 10 CFR states, The Commission will evaluate determinations under paragraph (g)(5) of this section that code requirements are impractical.

The Commission may grant such relief and may impose such alternative requirements as it determines are authorized by law, and will not endanger life or property or the common defense and security, and are 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.

Pursuant to 10 CFR 50.55a(g)(5)(iii), Duke Energy has requested approval to continue use of an alternative to the requirements of 10 CFR 50.55a, "Codes and standards," during the fourth 10-year ISi interval for BSEP Units 1 and 2, on the basis that compliance with the ASME Code requirements is impractical due to plant design. Based on the above, and subject to the following technical evaluation, the NRC staff finds that there is a regulatory basis for the licensee to request, and the NRC to authorize, the proposed alternative.

3.0 TECHNICAL

EVALUATION OF RELIEF REQUEST ISl-06 3.1 Applicable ASME Code Requirements The ASME Code of record for BSEP Units 1 and 2 during the fourth 10-year ISi interval is the 2001 edition through 2003 addenda of the ASME Code,Section XI. The fourth 10-year ISi interval began on May 11, 2008, and is scheduled to end on May 10, 2018. The examination requirements for the pressure retaining welds in CRD housings are delineated in ASME Code, Subarticle IWB-2500, "Examination and Pressure Test Requirements," Table IWB-2500-1, "Examination Category 8-0, Pressure Retaining Welds in Control Rods Housings," Item 814.10, "Welds in CRD Housing." ASME Code, Figure IWB-2500-18, further defines the required volumetric or surface examination requirements of the peripheral CRD housing welds. Specifically, ASME Code requires essentially 100 percent volumetric or surface examination of 10 percent of the peripheral CRD housing welds. 3.2 Impracticality of Compliance The license stated that there are 36 CRD housings on the periphery, and each housing has an upper and lower weld (i.e., total of 72 welds). The licensee also stated that examination of 10 percent of these welds would require that the welds of four housings (i.e., 8 welds) be examined.

The licensee further stated that the as-installed configuration of the 36 peripheral CRD housings renders the performance of these examinations impractical.

Specifically, limited accessibility for the 36 peripheral CRD housing-to-flange welds is due to the close proximity of adjacent CRD housing flanges, neutron monitoring instrumentation and associated cabling, and horizontal beams, support bars and grids. Access to both the upper and lower welds from below is limited by a series of CRD housing support bars, grid plates, and grid clamps. Piping systems and associated components for BSEP, Units 1 and 2 were designed and fabricated before the examination requirements of ASME Code,Section XI were formalized and published.

Duke Energy stated that since the plant was not specifically designed to meet the requirements of the ASME Code,Section XI, literal compliance is not feasible or practical within the limits of the design of BSEP Units 1 and 2. The licensee provided photographs in Attachment 3 of the request to show that during the fourth 10-year ISi interval that ASME Code required examinations of the lower CRD housing tube-to-flange welds are impractical.

3.3 Licensee's

Proposed Alternative In accordance with 1 O CFR 50.55a(g)(5)(iii}, the licensee requested relief for the referenced components below, on the basis that the required examination coverage of "essentially 100 percent" is impractical due to physical obstructions and severely limited access in the work area. The licensee stated that during the third 10-year ISi interval, it performed qualified surface examinations, which achieved 100 percent coverage with satisfactory results (i.e., no unacceptable flaws, and no evidence of degradation mechanisms) on eight upper CRD housing tube-to-tube welds. Duke Energy stated that as an alternative it proposes to perform surface examinations on four additional upper CRD housing tube-to-tube welds, in lieu of the four lower housing tube-to-flange welds. The licensee further stated that this would provide the same total number of CRD housing welds (i.e., 8 welds) for examination.

The tables below provided the selected CRD housing locations for each of the BSEP units, along with the anticipated percent coverage for each location.

BSEP Unit 1 Original Sample Additional Sample 1C11-CRD06-11-SW2 100% Coverage 1C11-CRD38-4 7-SW2 100% Coverage 1C11-CRD06-15-SW2 100% Coverage 1C11-CRD42-47-SW2 100% Coverage 1C11-CRD 10-07 -SW2 100% Coverage 1C11-CRD46-39-SW2 100% Coverage 1C11-CRD14-07-SW2 100% Coverage 1C11-CRD46-43-SW2 100% Coveraoe BSEP Unit 2 Orioinal Sample Additional Sample 2C12-CRD38-47-SW2 100% Coverage 2C12-CRD06-11-SW2 100% Coverage 2C12-CRD42-47-SW2 100% Coverage 2C 12-CRD06-15-SW2 100% Coveraoe 2C12-CRD46-39-SW2 100% Coverage 2C12-CRD10-07-SW2 100% Coverage 2C12-CRD46-43-SW2 100% Coverage 2C12-CRD14-07-SW2 100% Coverage The licensee stated that examining the four additional upper CRD housing welds in lieu of the lower CRD housing welds, will provide reasonable assurance of the integrity of the CRD housing welds. The licensee further stated that as ASME Code, Class 1 components, visual (VT-2) examinations are also performed on these components during system pressure tests for each refueling outage, under Table IWB-2500-1, Examination Category B-0. The licensee stated that these examinations were most recently completed in 2014 and 2015 for BSEP Units 1 and 2 respectively, with no evidence of leakage identified in the welds for these components.

Subsequent to the licensee's submission, it was noted that during its previous submission for a similar relief request, dated May 8, 2009 (ADAMS Accession No. ML091340100), the licensee used slightly different weld identification numbers for the same BSEP Unit 2 CRD housing welds. By letter dated January 19, 2017, the licensee stated that BSEP Unit 2 CRD housing weld numbers used in its current request, are from controlled plant drawings for the CRD welds. The licensee also stated that for the prior relief request (dated May 8, 2009), it used the CRD housing weld numbers from a plant database used to track ISi activities.

The licensee further stated that the two identification systems differ only with the "system designator

portion, that is, 2C12-CRD14-07-SW2 was previously incorrectly identified as 2C11-CRD10-07-SW2, for BSEP Unit 2. The licensee stated that the discrepancy for the BSEP Unit 2 weld identification numbers has been entered into the Corrective Action Program, and the weld designation numbers in its current submittal are correct. 3.4 NRC Staff Evaluation The ASME Code requires 100 percent volumetric or surface examination of 1 O percent of the peripheral CRD housing welds. The licensee has elected to perform surface examinations on the selected CRD housing welds. However, due to physical obstructions for the lower CRD housing tube-to-flange weld, the required inspection coverage could not be obtained.

The licensee had requested a similar relief request by letter dated May 8, 2009, due to physical obstructions imposed by design. Specifically, the licensee had stated that the location of vessel appurtenances, which include insulation support rings, structural and component supports, adjacent CRD housing flanges, and neutron monitoring instrumentation and associated cabling, limits the available access for the lower flange welds. The NRC approved the licensee's relief request by letter dated April 7, 201 O (ADAMS Accession No. ML 100491269).

The design of the BSEP Units 1 and 2 has not changed. Additionally.

the licensee has verified, during this interval, that it is impractical to perform the ASME Code required surface or volumetric examinations of the lower CRD housing tube-to-flange welds for the peripheral CRD housings.

The NRC staff finds that the licensee's proposal to examine four additional CRD housing tube-to-to tube welds meets the intent of the ASME Code, as far as the total number of CRD housing welds being examined.

Although the ASME Code-required coverage could not be obtained, the techniques employed provided full examination coverage for the upper welds, Based on the aggregate coverage obtained for the subject welds, the extent of the examinations, and considering the licensee's performance of essentially 100 percent examination coverage of welds with similar material, environment and expected degradation, it is reasonable to conclude that if significant service-induced degradation is present in the lower tube-to-flange welds, some evidence of degradation would have been detected in the upper welds. The NRC staff noted, that the upper flange welds would be expected to have somewhat higher operating temperatures as well as stresses, which would make them more susceptible to various degradation mechanisms.

Furthermore, the VT-2 examinations performed on these components during system pressure tests for each refueling outage, provide additional assurance that if significant service-induced degradation occurs, it will be detected during an outage. Therefore, the NRC staff has determined that granting relief 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.

The NRC staff has reviewed the licensee's submittal and concludes that ASME Code examination coverage requirements are impractical for the lower CRD housing-to-flange welds. The NRC staff also concludes that examinations performed on additional upper CRD housing tube-to-tube welds provide reasonable assurance of structural integrity of the subject welds since both the upper and lower CRD housing welds are subject to similar degradation mechanisms and conditions.

The NRC staff also determined that based on the VT-2 examinations performed during each outage, it is reasonable to conclude that if significant service-induced degradation had occurred, evidence of it would have been detected by these examinations.

4.0 CONCLUSION

As set forth above, the NRC staff determines that the licensee has adequately addressed all of the regulatory requirements set forth in 1 O CFR 50.55a(g)(6)(i).

Accordingly, the NRC staff has determined that granting relief 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.

Therefore, the NRC grants relief for the subject examinations of the components contained in RR ISl-06 for BSEP Units 1 and 2 during the fourth 10-year ISi interval.

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

Principal Contributor:

Roger Kalikian Date: February 27, 2017