ML20217E684

Safety Evaluation Accepting Code Case N-547, Alternative Exam Requirements for Pressure Retaining Bolting of CRD Housings

ML20217E684
Person / Time
Site:	Brunswick
Issue date:	04/23/1998
From:	NRC (Affiliation Not Assigned)
To:
Shared Package
ML20217E620	List: ML20217E615 ML20217E684
References
NUDOCS 9804270377
Download: ML20217E684 (5)

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SAFETY EVALUATION BY THE OFFICE OF NUCI FAR REACTOR REGULATIOR SECOND 10-YEAR INTERVAL INSERVICE INSPECTION PROGRAM PLAN REQUEST AR USE OF CODE CASE N-547 AS AN ALTERNATIVE BRUNSWICK STEAM ELFCTRIC PLANT UNIT NOS.1 AND 2 CAROLINA POWER & LIGHT COMPANY DOCKET NOS: 50-325 AND 50-324

1.0 INTRODUCTION

The Technical Specifications (TS) for Brunswick Steam Electric Plant, Units 1 and 2 state that the inservice inspection of the American Society of Mechanical Engineers (ASME) Code (Code)

Class 1,2, and 3 components shall be performed in accordance with Section XI of the ASME Boiler and Pressure Vessel (B&PV) Code and applicable addenda as required by 10 CFR 50.55a(g), except where specific written relief has been granted by the Commission pursuant to 10 CFR 50.55a(6)(g)(i).10 CFR 50.55a(a)(3) states that attematives to the requirements of paragraph (g) may be used, when authorized by the NRC, if (i) the proposed altematives would provide an acceptable level of quality and safety, or (ii) compliance with the specified requirements would result in hardship or unusual difficulty withou; 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 pre-service examination requirements, set forth in the ASME Code,Section XI, " Rules for Inservice inspection of Nuclear Power Plant Components," to the extent practical within the limitations of design, geometry, and materials of ccnstruction of the components. The regulations require i 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 incorporated by reference in 10 CFR 50.55e(b) 12 months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein. The applicable edition of Section XI of the ASME Code for the Brunswick Steam Electric Plant, Units 1 and 2 second 10-year inservice inspection (ISI) interval is the 1980 Edition through Winter 1981 Addenda.

Pursuant to 10 CFR 50.55a(g)(5), if the licensee determines that conformance with an examination requirement of Section XI of the ASME Code is not practical fos its facility, information shall be submitted to the Commission in support of that determination and a request made for relief from the ASME Code requirement. After evaluatio1 of the determination, 9804270377 980423 Enclosure PDR ADOCK 05000324 P PDR

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l pursuant to 10 CFR 50.55a(g)(6)(i), the Commission may grant relief and may impose alternative requirements that are determined to be authorized by law, will not endanger life, property, or the common defense and security, and are otherwise in the public interest, giving I due consideration to the burden upon the licensee that could result if the requirements were l imposed.

l By letter dated November 3,1997, Carolina Power and Light company (licensee) submitted an alternative to use Code Case N-547 "Altemative Examination Requirements for Pressure Retaining Bolting of Control Rod Drive (CRD) Housings,Section XI, Division 1, approval date l

August 24,1995,"in lieu of the ASME,Section XI Code requirements for Brunswick Steam Electric Plant, Units 1 and 2.

i 2.0 EVALUATION The staff, with technical assistance from its contractor, the Idaho National Engineering and Environmental Laboratory (INEEL), has evaluated the information provided by the licensee in support of its second 10-year interval inservice inspection (ISI) program plan attemative to use Code Case N-547 in lieu of the Code requirements for Brunswick Steam Electric Plant, Units 1 l and 2. Based on the results of the review, the staff adopts the contractor's conclusions and l recommendations presented in the attached Technical Letter Report.

The Code requires a VT-1 visual examination of CRD bolting, studs, and nuts when the CRD housing is disassembled. The licensee has proposed an alternative in lieu of the Code  !

requirement to use Code Case N-547. Code Case N-547 eliminates the VT-1 visual examination of CRD bolting. In addition, the licensee stated that "When control rod drive bolting is reused, it will perform a visual (VT-1) examination of the control rod drive botting prior to reinstallation. Othenuise, use the alternative contained in American Society of Mechanical l EngineersSection XI Code Case N-547, provided that control rod drive bolting is replaced with j new bolting."

The staff determined that Code Case N-547, as supplemented by the VT-1 examination identified above, is acceptable in that the proposed attemative provides assurance of component integrity. Therefore, the licensee's proposal to implement Code Case N 547 is authorized for CRD bolting that is replaced with new bolting that has received a quality receipt inspection and when bolting is reused, the licensee has proposed as part of its attemative to perform a VT-1 visur e.xamination of the bolting prior to reinstallation.

3.0 CONCLUSION

The staff concludes the licensee's proposed attemative, which includes use of Code Case N-547, is authorized pursuant to 10 CFR 50.55a(a)(3)(i) for CRD bolting that is replaced with new botting that has received a quality receipt inspection, and when botting is reused, the licensee performs a VT-1 visual examination of the botting prior to reinstallation. This attemative provides an acceptable level of quality and safety. The licensee's proposed attemative to use Code Case N-547, as supplemented, is authorized for the current interval or until such time as the Code Case is published in a future revision of Regulatory Guide 1.147. From that time, if the licensee continues to implement Code Case N-547, the licensee is to follow all provisions in the Code Case with limitations issued in Regulatory Guide 1.147, if any.

Principal Contributor. T. McLellan, ECGB Date:

TECHNICAL LETTER REPORT I ON SECOND 10-YEAR INTERVAL INSERVICE INSPECTION PROPOSED ALTERNATlVE CAROLifjA POWER & LIGHT COMPANY ,

l BRUNSWICK STEAM ELECTRIC PLANT. UNITS 1 AND 2 DOCKET NUMBERT 50-325. 50-324

1. INTRODUCTION By letter dated November 3,1997, the licensee, Carolina Power & Light Company (CP&L), submitted a proposed alternative to the requirements of the ASME Code,Section XI, for the Brunswick Steam Electric Plant (BSEP), Units 1 and 2. This proposed attemative is for the second 10-year inservice inspection (ISI) interval. The Idaho National Engineering and Environmental Laboratory (INEEL) staff's evaluation of the proposed attemative is in the following section.

2. EVALUATION The information provided by CP& L in support of the proposed attemative to the Code requirements has been evaluated and the basis for disposition is documented below.

The Code of record for the BSEP, Units 1 and 2, second 10-year ISI interval, which ends May 10,1998, is the 1980 Edition through Winter 1981 Addenda of Section XI of the ASME Boiler and Pressure Vessel Code.

Reauest For Authorization to Use ASME Section XI Code Case N-547 Code Reauirement: Section XI, Table IWB-2500, Examination Category B-G-2, item B7.80, requires a visual (VT-1) examination of the surfaces of the bolts, studs, and nuts of control rod drive (CRD) housings when the CRD is disassembled.

Licensee's Prooosed Alternative (as stated):

'In accordance with 10 CFR 50.55(a)(3)(i), CP&L requests approval for the BSEP, Unit Nos.1 and 2, to use the attemative examination requirement in ASME Section XI Code Case N 547, Attemative Requirement for Pressure Retaining Botting of CRD (CRD)

Housings. When CRD bolting is reused, CP&L will perform a VT-1 examination of the  !

CRD bolting prior to reinstallation. Otherwise, CP&L will use the alternative contained in ASME Section XI Code N-547, provided that the CRD brCing is replaced with new bolting. CP&L proposes to use the attemative provisions of ASME Section XI Code Case N-547 for the remainder of the second 10-year inservice inspection interval, or until such time as ASME Section XI Code Case N-547 is incorporved into Regulatory Guide 1.147,

" Inservice inspection Code Case Acceptability ASME Section XI Division 1."

Attachment

Licensee's Basis for the Proposed Altemative (as stated):

"The ASME has recognized, based on industry experience, that it is no longer necessary to perform VT-1 examinations at the CRD housings. Only innocuous indications of CRD housing bolted connections have been identified at boiling water reactor plants and none of these indications has caused a failure of the bolted connection. ASME Section XI Code Case N-547 was approved by the ASME Code committee on August 24,1995, but has not yet been incorporated into Regulatory Guide 1.147. The applicability index l

included in Supplement 6 to the 1995 Edition of the ASME Code,Section XI states that Code Case N-547 is applicable to versions of Section XI from the 1080 Edition, with the Winter 1981 Addenda, up to and including the 1995 Edition.

"The primary purpose of inservice examinations is to verify that service-related degradation of components has not occurred. A second reason for inservice examinations is to verify the quality of components prior to reinstallation."

"When control rod drive bolting is being replaced with new bolting, quality inspections, performed during receipt of new botting, provide an acceptable verification of the bolting quality, in the case of botting being reused, it is important that the condition of these bolts, studs, and nuts be verified prior to re-installation. Therefore, when control rod drive bolting is reused, CP&L will perform VT-1 examination of the control rod drive bolting prior to reinstallation. Otherwise, CP&L will use the attemative contained in ASME Section XI Code Case N-547, provided that control rod drive bolting is replaced with new bolting."

"This request to use ASME Section XI Code Case N-547 is similar to a request made for the Millstone Nuclear Power Station, Unit No.1. The Millstone request was approved by an NRC Safety Evaluation dated December 7,1995."

Evaluation: The Code requires a VT-1 visual examination of CRD bolting, studs, and nuts when the CRD housing is disassembled. The licensee has requested relief from this Code requirement and proposed an attemative to the Code requirement that includes the use of Code Case N-G47. Code Case N-547 eliminates the VT-1 visual examination of CRD bolting. The INEEL staff believes that Code Case N-547 is acceptable if the licensee replaces the botting with new material, and commits to performing a VT-1 visual inspection on any botting to be re-used. Maintenance activities such as disassembly and reassembly of components often require the removal of botting. Mishandling of the bolting can result in galling of threads, bending and other damage that may reduce the reliability of the bolting. The INEEL staff believes that when CRD bolting is replaced with used bolting, a VT-1 visual examination should be performed to verify that the condition of the CRD botting is acceptable. However, when the CRD bolting is being replaced with new bolting, the staff believes that a quality receipt inspection will provido an acceptable verification of the bolting integrity. The licensee has committed that "When control rod drive bolting is reused, perform visual (VT-1) examination of the control rod drive botting prior to reinstallation. Otherwise, use the attemative contained in American Society of '

Mechanical EngineersSection XI Code Case N-547, provided that control rod drive bolting is replaced with new bolting."

The INEr . staff recommends that the licensee's proposal to implement Code Case N-547 be authorized for CRD bolting that is replaced with new botting that has received a quality receipt inspection. When botting is reused, the licensee has committed to perform a VT-1 visual examination of the botting prior to reinstallation. Satisfying this condition will provide an acceptable level of quality and safety.

4. CONCLUSION Tha INEEL staff has reviewed the licensee's proposed attemative, which includes use of Code Case N-547. In accordance with 10 CFR 50.55a(a)(3)(i), the INEEL staff recommends that the licensee's proposal to implement Code Case N-547 be authorized for CRD bolting that is replaced with new bolting that has received a quality receipt inspection. When bolting is reused, the licensee has committed to perform a VT-1 visual examination of the botting prior to reinstallation. With the conditions noted, the licensee's alternative will provide an acceptable level of quality and safety. Therefore, use of Code Case N-547 should be authorized for the present interval or until such time as the Code Case is published in a future revision of Regulatory Guide 1.147. From that time, if the licensee continues to implement this Code Case, the licensee is to follow all provisions in the Code Case with limitations issued in Regulatory Guide 1.147, if any.

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