ML18153B133
| ML18153B133 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 11/01/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML18153B132 | List: |
| References | |
| NUDOCS 9411070367 | |
| Download: ML18153B133 (9) | |
Text
e ENCLOSURE 1 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION OF THE SECOND TEN-YEAR INTERVAL INSERVICE INSPECTION REQUESTS FOR RELIEF
1.0 INTRODUCTION
FOR VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION, UNIT 1 DOCKET NUMBER: 50-280 The Technical Specifications for Surry Power Station, Unit 1, state that the inservice inspection and testing 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 as required by 10 CFR 50.SSa(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 requirements 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 XJ, "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 coriducted during the first ten-year interval and sObsequent 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.SSa(b) on the date twelve months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein. The 1980 Edition, through the Winter 1980 Addenda, of Section XI is the applicable edition of the ASME Code for the Surry Power Station, Unit 1 second 10-year'inservice inspection (ISI)
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e Interval. The components (including supports) may meet the requirements set forth in subsequent editions and addenda of the ASME Code incorporated by reference in lo 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 pr act i cal for its facility, information sha 11 be submitted to the Commission in support of that determination and a request made for relief from the ASME Code requirement.
After evaluation of the determination, 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 due consideration to the burden upon the licensee that could result if the requirements were imposed.
In a letter dated April 29, 1994, the licensee, Virginia Electric and Power Company (VEPCo), requested relief from the requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Code,Section XI.
In response to a conference call with the staff on July 12, 1994, VEPCo provided additional information on RR-020 in a letter dated July 25, 1994.
2.0 EVALUATION AND CONCLUSIONS The staff, with technical assistance from the Idaho National Engineering Laboratory (INEL), has evaluated the information provided by the licensee in support of its Request for Relief No. RR-020.
Based on the information submitted, the staff adopts the contractor's conclusions and recommendations presented in the attached Technical Evaluation Letter Report.
Request for Relief RR-020 covered four welds: 1-12 and 1-29 (Class 1) and 2-09 and 2-02 (Class 2).
Due to various geometrical obstructions or interferences, the licensee could not obtain "essentially 100%" volumetric examination on these welds.
Due to the extent of the examinations completed, however, reasonable assurance of continued integrity of the welds is provided.
Request for Relief RR-020 is granted pursuant to 10 CFR 50.55a{g){6)(i) as the Code 2
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requirements are impractical to comply with given due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility.
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TECHNICAL EVALUATION LETTER REPORT ON THE SECOND TEN-YEAR INTERVAL INSERVICE INSPECTION REQUEST FOR RELIEF RR-020
1.0 INTRODUCTION
FOR VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION, UNIT 1 DOCKET NUMBER:
50-280 ENCLOSURE 2 The licensee, Virginia Electric and Power Company, submitted Relief Request RR-020 for the second IO-year inservice inspection (ISi} interval at Surry Power Station, Unit 1, in a letter dated April 29, 1994.
The Surry Unit I second IO-year ISi.interval ended in October 1993.
Relief Request RR-020 concerns partial volumetric examinations of several Class I and 2 welds.
The Idaho National Engineering Laboratory has evaluated the subject request for relief in the following section.
- 2. 0 EVALUATION The Code of record for the second IO-year interval at Surry Unit I is the 1980 Edition, through the Winter 1980 Addenda, of ASME Section XI.
The information provided by the licensee in support of Relief Request RR-020 has been evaluated and the basis for disposition is documented below.
A.
Request for Relief No. RR-020:
(Part I) Table IWB-2500-1, Examination Category B-J, Items B9.ll and B9.12; and Code Case N-460, Class I Piping Welds Code Requirement:
Examination Category B-J, Items B9.ll and 89.12 require that "essentially 100%" of the volume of selected welds be examined.
ASME Code Case N-460 further clarifies the intent of the Code by stating that examination volumes of greater than 90% meet the essentially 100% requirement.
Licensee's Code Relief Request: The-licensee requested relief from the Code requirement for essentially 100% volumetric examinations of primary system piping Welds 1~12 and 1-19.
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Licensee's Basis for Requesting Relief (as stated):
I Comeonent Identification I
ASME Weld System Line/Mark No.
Drawing No.
Class No.
1 1-12 RC 27"-RC-6-2501R 11448-WMKS-OlOlAZ-1 1
1-19 RC 31"-RC-8-2501R 11448-WMKS-0102AZ-1 "The components listed above have been examined to the extent practicable as required by the Code.
Due to interferences of other components or weld joint geometry the reduction in coverage for the listed components was greater than 10%.
Tables SR-020-1, 2, and 31 are provided detailing the limitations experienced. Amplifying sketches or drawings are also provided2
- Alternative components could not be substituted for examination due to the mandatory selection requirements of the Code, or because the examination coverage attained was representative of what could be expected for that type configuration."
Licensee's Proposed Alternative (as stated):
"It is proposed that the examinations already completed at the reduced coverage be counted as meeting the Code requirements."
Evaluation: Virginia Electric and Power Company provided additional information in a letter dated Jul~ 25, 1994.
The letter references Westinghouse Report 11778, Demonstration of Flaw Detection and Characterization Capability for Ultrasonic Examination of Main Coolant Loop Welds, March 1988.
Weld number 1-12 is a cold leg pipe-to-reactor coolant pump (RCP) weld.
Due to geometry and the cast metallurgical structure of the RCP nozzle, UT examination is extremely limited when performed from the nozzle side of the weld.
It would be impractical for the licensee to redesign and replace the RCP nozzle.
The licensee has qualified a dual element 45° longitudinal technique for examining this weld, as recommended in the report.
In addition, a 45° extended shear wave technique, performed from the pipe side of the weld only, was used to supplement the examination.
2 These tables have not been included in this evaluation.
Sketches and/or drawings are not included in this evaluation.
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Weld 1-19 is a longitudinal fabrication seam weld on a primary system elbow.
The Code requires examination of at least one pipe diameter, but not more than twelve inches, of the subject longitudinal weld.
The licensee has provided information that indicates the presence of an ASME Code Section III fabrication tag located over a portion of Weld 1-19.
The 1-inch wide by 4-inch long fabrication tag limits UT examination of the weld.
However, the licensee has completed a large percentage of the required exami~ation (greater than 84% on each scan), which provides reasonable assurance of the continued integrity of Weld 1-19.
While the examination coverage was less than that required by the Code, it appears to be adequ~te to detect service-induced flaws that would typically originate from the inner surface heat-affected zone (HAZ) of the welds.
Therefore, the examinations provided reasonable assurance of the continued integrity of Welds 1-12 and 1-19.
For these reasons, it is recommended that, pursuant to 10 CFR 50.55a(g)(6)(i), relief be granted for these welds.
B.
Request for Relief No. RR-020:
(Part II) Table IWC-2500-1, Examination Category C-A, Item Cl.30; and Code Case N-460, Steam Generator Tubesheet-to-Shell Weld Code Requirement:
Examination Category C-A, Item Cl.30 requires that "essentially 10b%" of the volume of selected shell welds be examined.
ASME Code Case N-460 further clarifies the intent of the Code by stating that examination volumes of greater than 90% meet the essentially 100%
- requirement.
Licensee's Code Relief Request:
The licensee requested relief from the Code requirement for essentially 100% volumetric examination of steam generator secondary tubesheet-to-shell welds.
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Licensee's Basis for Requesting Relief (as stated):
Comoonent Identification ASME Weld System Line/Mark No.
Drawing No.
Class No.
2 2-02 RC 1-RC-E-lA 11448-WMKS-RC-E-lA.1 RC 1-RC-E-18 11448-WMKS-RC-E-18.l RC 1-RC-E-lC 11448-WMKS-RC-E-lC.1 "The components listed above have been examined to the extent practicable as required by the Code.
Due to interferences of other components or weld joint geometry the reduction in coverage for the listed components was greater than 10%.
Tables SR-020-1, 2, and 33 are provided detailing the limitations experienced. Amplifying sketches or drawings are also provided4
- Alternative components could not be substituted for examination due to the mandatory selection requirements of the Code, or because the examination coverage attained was representative of what could be expected for that type configuration."
Licensee's Proposed Alternative (as stated):
"It is proposed that the examinations already completed at the reduced coverage be counted as meeting the Code requirements."
Evaluation:
Weld 2-02 is a steam generator secondary-side tubesheet-to-shell weld.
Interferences from handholes, nozzles, and welded lugs in the vessel shell reduce the ultrasonic accessibility of the weld.
The licensee would be required to remove these obstructions, i.e., re-design and replace the steam generators, to complete the Code-required volumetric coverage.
These measures are considered to be impractical.
Furthermore, the licensee has completed a large percentage of the required examination volume (greater than 84.5% on each scan),
which provides reasonable as$urance of the continued integrity of the weld.
It is therefore recommended that, pursuant to 10 CFR 50.55a(g)(6)(i), relief be granted for Weld 2-02.
3 4
These tables have not been included in this evaluation.
Sketches and/or drawings are not included in this evaluation.
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C.
Request for Relief No. RR-020:
{Part III) Table IWC-2500-1. Examination Category C-B. Item C2.21; and Code Case N-460, Steam Generator Nozzle-to-Shell Weld Code Requirement:
Examination Category C-8, Item C2.21 requires that "essentially 100%" of the volume of selected welds be examined.
ASME Code Case N-460 further clarifies the intent of the Code by stating that examination volumes of greater than 90% meet the essentially 100%
requirement.
Licensee's Code Relief Request:
The licensee requested relief from the Code requirement for essentially 100% volumetric examination of a steam generator secondary nozzle-to-shell weld.
Licensee's Basis for Requesting Relief (as stated):
I Comeonent Identification I
ASME Weld System Line/Mark No.
Drawing No.
Class*
No.
2 2-09 RC 1-RC-E-IA 11448-WMKS-RC-E-IA.2 "The components listed above have been examined to the extent practicable as required by the Code.
Due to interferences of other components or weld joint geometry the reduction in coverage for the listed components was greater than 10%.
Tables SR-020-1, 2, and 35 are provided detailing the limitations experienced. Amplifying sketches or drawings are also provided6
- Alternative components could not be substituted for examination due to the mandatory selection requirements of the Code, or because the examination coverage attained was representative of what could be expected for that type configuration."
Licensee's Proposed Alternative (as stated):
"It is proposed that the examinations already completed at the reduced coverage be counted as meeting the Code requirements."
Evaluation:
Weld 2-09 is a steam generator secondary-side nozzle-to-shell weld.
An insulated support band is located on the vessel side of this weld, limiting access for ultrasonic scanning.
The geometry 5
6 These tables have not been included in this evaluation.
Sketches and/or drawings are not included in this evaluation.
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e of the nozzle, with non-parallel inside and outside surfaces, also limits scans from the nozzle side of the weld.
The licensee would be required to remove the steam generator support band, or re-design and replace the nozzle, to increase the extent of coverage.
For these reasons, the Code-required examination coverage is considered to be impractical for Weld 2-09.
The licensee has examined a large percentage of the required volume (greater than 83% on each scan), which provides reasonable assurance of the continued integrity of this weld.
It is recommended that, pursuant to 10 CFR 50.55a(g}(6}(i}, relief be granted for Weld 2-09.
3.0 CONCLUSION
The licensee submitted Request for Relief SR-020 concerning volumetric examination coverage(s} of several ASME Code Class 1 and 2 welds.
Based on the geometric weld configurations and interferences with other components it has been determined that it is impractical for the licensee to complete the full 100% examinations.
The completed volumetric percentages provide reasonable assurance of the continued integrity of the welds.
Therefore, in accordance with 10 CFR 50.55a(g)(6)(i}, it is recommended that the licensee's request be granted.
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