ML20133G156
| ML20133G156 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 01/10/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20133G150 | List: |
| References | |
| NUDOCS 9701150189 | |
| Download: ML20133G156 (8) | |
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UNITED STATES p
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NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20666 4 001 o
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ENCLOSURE 1 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION OF THE SECOND 10-YEAR INTERVAL INSERVICE INSPECTION PROGRAM PLAN RE0 VESTS FOR RELIEF NOS. NnE-27. NDE-28. AND NDE-29 f.Q3 VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION. UNIT 1 DOCKET NUMBER:
50-338
1.0 INTRODUCTION
The Technical Specifications for North Anna Power Station, Unit I state that the inservice inspection of the American Society of Mechanical Engineers (ASME) Code Class 1, 2, and 3 components shall be performed in accordance with Section XI of the ASME Boiler and Pressure Vessel Code and applicable Addenda i
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(g)(6)(i).
10 CFR 50.55a(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 raquirements would result in hardship or unusual difficulties 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, " Rules for Inservice 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 conducted during the first ten-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(b) twelve 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 North Anna Power Station, Unit I second 10-year inservice inspection (ISI) interval is the 1983 Edition through Summer 1983 Addenda.
The components (including supports) may meet the requirements set forth in subsequent editions and addenda of the ASME Code incorporated by reference in 10 CFR 50.55a(b) subject to the limitations and modifications listed therein and subject to Commission approval.
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 for 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.
9701150189 970110 PDR ADOCK 05000339 G
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2 After evaluation of tt3 determination, pursuant to 10 CFR 50.55a(g)(6)(1), 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 due consideration to the burden upon the licensee that could result if the requirements were imposed.
In a letter dated June 13, 1996, Virginia Electric and Power Company submitted to the NRC its Second Ten-Year Interval Inservice Inspection Program Plan Requests for Relief Nos. NDE-27, NDE-28, and NDE-29 for the North Anna Power Station, Unit 1.
2.0 EVALUATION AND CONCLUSIONS The staff, with technical assistance from its contractor, the Idaho National Engineering Laboratory (INEL), has evaluated the information provided by the licensee in support of its second ten-year interval inservice inspection program plan Requests for Relief Nos. NDE-27, NDE-28, and NDE-29 for the North Anna Power Station, Unit 1.
Based on the information submitted, the staff adopts the contractor's conclusions and recommendations presented in the Technical Letter Report..
The staff has reviewed the licensee's Relief Requests Nos. NDE-27, NDE-28, and NDE-29, and concludes that examinations to the extent required by the Code are impractical and that the licensee's proposed alternatives to Code requirements will provide reasonable assurance of structural integrity. The granting of this relief is authorized by law and will not endanger life o' 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.
Therefore, relief is granted pursuant to 10 CFR 50.55a(g)(6)(i) for Requests for Relief Nos. NDE-27, NDE-28, and NDE-29 as requested.
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s ENCLOSURE 2 TECHNICAL LETTER REPORT ON THE SECOND 10-YEAR INSERVICE INSPECTION INTERVAL REQUESTS FOR RELIEF E9E i
VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION. UNIT 1 DOCKET NUMBEP:
50-338 l
4 l.0 INTRODUCTION By letter dated June 13, 1996, the licensee, Virginia Electric and Power Company (VEPCO), submitted Requests for Relief NDE-27, NDE-28, and NDE-29 for Nortih Anna Power Station, Unit 1.
The Idaho National Engineering Laboratory (INEL) staff has evaluated these requests in the followingsectfon.
2.0 EVALUATION The Code of record for the North Anna Power Station, Unit 1, second 10-year inservice inspection interval, which is scheduled to end in December 1998, is the 1983 Edition through Summer 1983 Addenda of the l
American Society of Mechanical Engineers Boiler and Pressure Vessel Code,Section XI. The information provided by the licensee in support of the requests for relief from Code requirements has been evaluated and the bases for disposition are documented below.
A.
Reauest for Relief NDE-27. Examination Cateaory B-J. Item B9.31. Branch Connection Walds in Pioina NPS 4 and Greater Code Reauirement: Table IWB-2500-1, Examination Category B-J, Item B9.31 requires 100% surface and volumetric examination of branch connection welds as defined by Figures IWB-2500-9, -10, and -11, as applicable.
Licensee's Code Relief Reauest: The licensee requested relief from performing the Code-required volumetric examination of the following branch connection welds.
l 2
Weld Number Line Number Cumulative % Coverage SW-32 6"-RC-21-1502-Q1 34 SW-41 12"-RC-24-1502-Q1 35 SW-43 6"-RC-20-1502-Q1 33 Licensee's Basis for Reauestino Relief (as stated):
4 "The components listed above have been examined to the extent practical as required by the Code.
The Code required volumetric examination coverage was reduced due to nozzle configuration, weld joint geometry, and material type from which the components are constructed. The scope of volumetric examination coverage completed for the above listed welds is listed in Table NDE-27-1. The required surface examinations had no experienced.' Figure NDE-27-1 is provided detailing the limitations limitations.
Alternative components could not be substituted for the examination due to the mandatory selection requirements of the Code."
Licensee's Proposed Alternative Examination (as stated):
"It is proposed that the examinations already completed at the reduced coverage be counted as meeting the Code requirements."
Evaluation: The Code requires that the subject branch connection welds receive 100% volumetric and surface examinations. The INEL staff has reviewed the information and figures provioed by the licensee that describe the limitations and depict the nozzle / weld joint configurations. Because of the joint configurations and the limited sound path associated with austenitic steel castings, the Code-required volumetric examination is impractical. To obtain complete volumetric coverage, design modifications would be required, causing a significant burden on the licensee.
The licensee proposes to perform the volumetric examinations to the extent practical, resulting in tumulative volumetric examination coverage between 33% and 35% for the subject welds. All three welds received 100% surface examinatans. Based on the examination coverage obtained, in conjunction with the 100% surface examination, and on other
'N t included in this report.
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3 examinations of similar components, it can be concluded that a pattern of degradation, if present, would have been detected. As a result, reasonable assurance of structural integrity has been provided.
Therefore, it is recommended that relief be granted, pursuant to 10 CFR 50.55a(g)(6)(1).
B.
Reauest for Relief NDE-28. Examination Cateaory B-J. Item B9.11. Class 1 Circumferential Pioina Welds >4 NPS Code Reauirement:
Section XI, Table IWB-2500-1, Examination Category B-J, Item B9.ll, requires volumetric and surface examinations.of Class 1 circumferential piping welds as defined by Figure IWB-2500-8.
Licensee's Code-Relief Reauest: The licensee requested relief from performing the Code-required volumetric examination of the following welds.
Weld Number Line Number Cumulative % Coverage 32 31"-RC-8-1502-Q1 75 J
l 41 27 1/2"-RC-9-1502-Q1 49 Licensee's Basis for Reauestina Relief (as stated):
"The components listed above have been examined to the extent practical as required by the Code.
The Code required volumetric examination coverage was reduced due to weld joint geometry, and the material type l
from which the components are constructed. The scope of volumetric examination coverage completed for the above listed welds is listed in d
i Table NDE-28-1. The required surface examinations had no limitations, experienced.j8-1andNDE-28-2areprovideddetailingthelimitations Figures NDE-i Alternative components could not be substituted for j
examination due to the mandatory selection requirements of the Code."
i 4
i 2Not included in this report.
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1 3
4 licensee's Proposed Alternative Examination (as stated):
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i "It is proposed that the examinations already completed at the reduced coverage be counted as meeting the Code requirements."
Evaluation: The Code requires that the subject piping welds receive l
100% volumetric and surface examinations. The INEL staff has reviewed the information and figures provided by the licensee that describe the limitations and depict the weld joint configurations.
Because of the
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joint configurations and the limited sound path associated with austenitic steel castings, the Code-required volumetric examination is impractical. To obtain complete volumetric coverage, design modifications would be required, causing a sig-ricant burden on the licensee.
The licensee proposes to perform the volumetric examination to the extent practical, resulting in cumulative volumetric examination coverages of 75% and 49%, respectively, for the subject welds.
Both welds received 100% surface examination coverage. Based on the examination coverage obtained, in conjuncti0n with the 100% surface examination, and on other examinations of similar components, it can be concluded that a pattern of degradation, if present, would have been detected. As a result, reasonable assurance of structural integrity has been provided. Therefore, it is recommended that relief be granted, pursuant to 10 CFR 50.55a(g)(6)(i).
C.
Reauest for Relief NDE-29. Exanination Cateaory B-J. Item 89,21. Class 1 Circumferential Pioe Welds <4 NPS Code Reauirement:
Section XI, Table IWB-2500-1, Examination Category B-J, Item B9.21, requires 100% surface examination of Class I circumferential pipe welds less than 4" nominal pipe size (NPS) as defined by Figure IWB-2500-8.
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Licensee's Code Relief Reauest: The licensee requested relief from performing the Code-required surface examination of Weld SW-32, Line i
2"-RC-220-1502-Ql.
Licensee's Basis for Reauestina Relief (as stated):
"The component listed above has been examined to the extent practical as required by the Code Case.
The Code required surface examination coverage was reduced due to the interference with a steel beam above the weld. This interference limited the examination of the weld to 61/2" of the total 8", 81.25%.3 Figure NDE-29-1 is provided detailing the limitations experienced.
Alternative components could not be substituted for examination due to the mandatory selection requirements
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of the Inservice Inspection Program for Class 1 piping welds which requires all welds adjacent to integral attachments to be examined."
Licensee's Proposed Alternative Examination (as stated):
i "It is proposed that the examinations already completed at the reduced coverage be counted as meeting the Code requirements."
Evaluation: The Code requires that the subject weld receive a 100%
surface examination. The figure provided by the licensee depicts the interference caused by a structural steel beam adjacent to the weld.
Consequently, the surface examination is impractical to perform to the extent required by the Code. To obtain complete surface coverage, design modifications would be required, causing a significant burden on the licensee.
The licensee proposes to perform the surface examination to the extent practical, resulting in examination coverage of 81% for the subject weld. Based on the examination coverage obtained, it can be concluded that a pattern of surface degradation, if present, would have been detected. As a result, reasonable assurance of structural integrity has been provided. Therefore, it is recommended that relief be granted pursuant to 10 CFR 50.55a(g)(6)(i).
3Not included in this report.
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3.0 CONCLUSION
i The INEL staff has evaluated the licensee's submittal.
For Requests for Relief NDE-27, NDE-28, and NDE-29, the staff concludes that examinations to the extent required by the Code are impractical and that the licensee's proposed alternatives to Code requirements will provide reasonable assurance of structural integrity. Therefore, it is recommended that relief be granted pursuant to 10 CFR 50.55a(g)(6)(i).