ML093561419
| ML093561419 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 01/07/2010 |
| From: | Boyce T Plant Licensing Branch II |
| To: | Burton C Carolina Power & Light Co |
| Vaaler, Marlayna, NRR/DORL 415-1998 | |
| References | |
| TAC ME0609, TAC ME0610, TAC ME0611, TAC ME0612, TAC ME0613, TAC ME0614, TAC ME0615 | |
| Download: ML093561419 (18) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 January 7, 2010 Chris L. Burton, Vice President Shearon Harris Nuclear Power Plant Carolina Power & Light Company Post Office Box 165, Mail Zone 1 New Hill, North Carolina 27562-0165
SUBJECT:
SHEARON HARRIS NUCLEAR POWER PLANT, UNIT 1 - REQUESTS FOR RELIEF 2R1-019, 2R1-020, 2R1-021, 2R1-022, 2R2-009, 2R2-010, AND 2R2-011 FOR THE SECOND 10-YEAR INTERVAL INSERVICE INSPECTION PROGRAM PLAN (TAC NOS. ME0609, ME0610, ME0611, ME0612, ME0613, ME0614, AND ME0615)
Dear Mr. Burton:
By letter dated February 5, 2009, as supplemented by "HNP-09-095, Response to Request for Additional Information Regarding Relief Requests 2R1-018, 2R1-019, 2R1-020, [[SSC" contains a listed "[" character as part of the property label and has therefore been classified as invalid., 2R1-022, 2R2-009, 2R2-010, & 2R2-011 for the Second 10-Year Inservice Inspection Program|letter dated September 24, 2009]], Carolina Power & Light Company (the licensee), now doing business as Progress Energy Carolinas, Inc., submitted Relief Requests (RRs) 2R1-019, 2R1-020, 2R1-021, 2R1-022, 2R2-009, 2R2-010, and 2R2-011 for the second 1O-year inservice inspection (lSI) interval at the Shearon Harris Nuclear Power Plant, Unit 1 (HNP), which was in effect from February 2, 1998, through and including May 1, 2008.
Specifically, the licensee requested relief in accordance with Title 10 of the Code of Federal Regulations (10 CFR), Section 50.55a(g)(5)(iii) from applicable requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI, "Rules for Inservice Inspection of Nuclear Power Plant Components," related to inspection of welds with limited coverage in ASME Code examination Categories B-A, B-A, B-D, B-B, C-A, C-B, and C-A, respectively.
Based on the information provided in RRs 2R1-019, 2R1-020, 2R1-021, 2R1-022, 2R2-009, 2R2-010, and 2R2-011, the Nuclear Regulatory Commission (NRC) staff concluded that it is impractical for the licensee to comply with the applicable ASME Code requirements, and that imposing these requirements would be a burden on the licensee. The NRC staff also finds that the licensee's proposed alternatives continue to provide reasonable assurance of structural integrity and are, therefore, acceptable.
Therefore, pursuant to 10 CFR 50.55a(g)(6)(i), the NRC staff grants the lSI program alternatives proposed in RRs 2R1-019, 2R1-020, 2R1-021, 2R1-022, 2R2-009, 2R2-010, and 2R2-011 for the second 10-year lSI interval at HNP, on the basis that they 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.
C.Burton
- 2 The NRC staff's safety evaluation is enclosed. If you have any questions regarding this matter, please contact Marlayna Vaaler at (301) 415-3178.
Sincerely, Thomas H. Boyce, Plant Licensing Bra h 11-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-400
Enclosure:
Safety Evaluation cc w/enclosure: Distribution via ListServ
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELIEF REQUESTS 2R1-019, 2R1-020, 2R1-021, 2R1-022, 2R2-009, 2R2-010, AND 2R2-011 ON FINAL DOCUMENTATION FOR THE SECOND 10-YEAR INSERVICE INSPECTION PROGRAM FOR LIMITED COVERAGE OF WELDS IN EXAMINATION CATEGORIES B-A, B-A. B-D, B-B, C-A, C-B, AND C-A, RESPECTIVELY SHEARON HARRIS NUCLEAR POWER PLANT, UNIT 1 CAROLINA POWER & LIGHT COMPANY DOCKET NO. 50-400
1.0 INTRODUCTION
By letter dated February 5, 2009 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML090540055), as supplemented by "HNP-09-095, Response to Request for Additional Information Regarding Relief Requests 2R1-018, 2R1-019, 2R1-020, [[SSC" contains a listed "[" character as part of the property label and has therefore been classified as invalid., 2R1-022, 2R2-009, 2R2-010, & 2R2-011 for the Second 10-Year Inservice Inspection Program|letter dated September 24, 2009]] (ADAMS Accession No. ML092740063), Carolina Power & Light Company (the licensee), now doing business as Progress Energy Carolinas, Inc., submitted Relief Requests (RRs) 2R1-019, 2R1-020, 2R1-021, 2R1-022, 2R2-009, 2R2-010, and 2R2-011 for the Shearon Harris Nuclear Power Plant, Unit 1 (HNP). The proposed RRs are for the second 1O-year inservice inspection (lSI) interval, in which the licensee adopted the 1989 Edition of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI, No Addenda, as the Code of Record. The second 1O-year lSI interval at HNP was in effect from February 2, 1998, through and including May 1, 2008.
The proposed RRs request relief in accordance with Title 10 of the Code of Regulations, (10 CFR) 50.55a(g)(5)(iii) from applicable requirements of the ASME Code,Section XI, "Rules for Inservice Inspection of Nuclear Power Plant Components," related to inspection of welds with limited coverage in ASME Code examination Categories B-A, B-A, B-D, B-B, C-A, C-B, and C-A, respectively. The ASME Code requires that 100 percent of the examination volumes or surface areas described in ASME Code.Section XI, Tables IWB-2500 and IWC-2500, be inspected during each interval. The licensee stated that inspections of 100 percent of the ASME Code-required volumes or surface areas are impractical to obtain at HNP.
The regulation in 10 CFR 50.55a(g)(5)(iii) states that when licensees determine that conformance with ASME Code requirements is impractical at their facility, they shall submit information to support this determination. The U.S. Nuclear Regulatory Commission (NRC) will evaluate such requests based on impracticality, and may impose alternatives, giving due consideration to public safety and the burden imposed on the licensee.
Enclosure
- 2 2.0 REGULATORY REQUIREMENTS Inservice inspection of 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 10 CFR 50.55a(g), except where specific relief has been granted by the NRC pursuant to 10 CFR 50.55a(g)(6)(i). The regulations in 10 CFR 50.55a(a)(3) state 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 components. The regulations require that inservice examination of components and system pressure tests conducted during the first 10-year lSI 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 into 10 CFR 50.55a(b), 12 months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein. The ASME Code of Record for the HNP second 10-year lSI interval, which ended on May 1, 2008, is the 1989 Edition of Section XI of the ASME Boiler and Pressure Vessel Code, with No Addenda.
The information provided by the licensee in support of the requests for relief from the ASME Code requirements listed above has been evaluated by the NRC staff. The bases for disposition and continued compliance with the regulatory requirements are documented below on an RR-specific basis, and Attachment 1 to this SE lists each RR and the status of approval.
3.0 TECHNICAL EVALUATION
3.1 Request for Relief 2R1-019. ASME Code.Section XI. Examination Category B-A. Items B1.11 and B1.21. Pressure Retaining Welds in Reactor Vessel, Circumferential Shell and Head Welds ASME Code Requirement ASME Code,Section XI, Examination Category B-A, Items B1.11 and B1.21, require essentially 100 percent volumetric examination, as defined by ASME Code,Section XI, Figures IWB-2500-1 and IWB-2500-3, of the length of reactor pressure vessel (RPV) circumferential shell and head welds. "Essentially 100 percent," as clarified by ASME Code Case N-460, "Alternative Examination Coverage for Class 1 and Class 2 Welds,"
is greater than 90 percent coverage of the examination volume, or surface area, as applicable. ASME Code Case N-460 has been approved for use by the NRC in Regulatory Guide 1.147, Revision 15 (RG 1.147, Revision 15), "lnservice Inspection Code Case Acceptability ASME,Section XI, Division 1."
- 3 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 of ASME Code Class 1 RPV Circumferential Shell Weld STHW-RV-04 and Circumferential Head Weld CHW-RV-17.
Licensee's Basis for Relief Req uest (as stated)
The limitations for RPV Lower Shell to Lower Head Circumferential Weld STHW-RV-04 are the four core support lugs integrally attached to the reactor vessel. The type of change needed to gain additional access would be the removal of core support lugs, which is not a possibility.
The limitations for RPV Lower Head Circumferential Weld CHW-RV-17 are the peripherally located Bottom Mounted Instrumentation (BMI) tubes integrally attached to the reactor vessel. The type of change needed to gain additional access would be the relocation of the BMI tubes, which is not possible.
Licensee's Proposed Alternative Examination The licensee did not propose an alternative examination; however, it did perform the ASME Code-required examinations to the extent practical.
Staff Evaluation The ASME Code requires essentially 100 percent volumetric examination of pressure retaining welds in the RPV. However, the design configuration of the RPV lower shell-to-Iower head circumferential weld and lower head circumferential weld limit complete examinations due to adjacent components such as instrument nozzles and support lugs. In order to effectively increase the examination coverage area, the RPV and adjacent components would require extensive design modifications or replacement.
This would place a burden on the licensee; thus, examining essentially 100 percent of the ASME Code-required volumes is considered impractical.
As shown in the sketches and technical descriptions included in the licensee's submittals, examinations of RPV Lower Shell-to-Lower Head Circumferential Weld STHW-RV-04 and RPV Lower Head Circumferential Weld CHW-RV-17 have been performed to the extent practical, with the licensee obtaining coverage of approximately 83.9 percent and 81.77 percent of the ASME Code-required inspection volumes, respectively.
Weld STHW-RV-04 was restricted by four core support lugs located at 0, 90, 180, and 270 degrees on the inside of the RPV. Weld CHW-RV-17 could only be scanned from a limited number of areas due to peripherally located 8MI tubes that are integrally attached to the RPV. All of the examinations were conducted with equipment, procedures, and personnel that were qualified by performance demonstration in
accordance with the ASME Code,Section XI, Appendix VIII. There were two indications detected and evaluated as being acceptable per ASME Code Section IW8-3510.
The licensee has shown that it is impractical to meet the ASME Code-required 100 percent volumetric examination coverage for the subject welds due to the proximity of integral RPV components. However, based on the volumetric coverage obtained, 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 to the extent practical provide reasonable assurance of the structural integrity of the subject welds.
3.2 Request for Relief 2R1-020, ASME Code,Section XI, Examination Category 8-A, Items 81.30 and 81.40, Pressure Retaining Welds in Reactor Vessel, Shell-to-Flange and Head-to-Flange Welds ASME Code Requirement ASME Code,Section XI, Examination Category 8-A, Item 81.30 requires essentially 100 percent volumetric examination, as defined by ASME Code,Section XI, Figure IW8-2500-4, of the length of RPV shell-to-flange welds. In addition, Item 81.40 requires essentially 100-percent volumetric and surface examination, as defined by ASME Code,Section XI, Figure IW8-2500-5, of the length of RPV head-to-flange welds. "Essentially 100 percent," as clarified by ASME Code Case N-460, is greater than 90 percent coverage of the examination volume, or surface area, as applicable. ASME Code Case N-460 has been approved for use by the NRC in RG 1.147, Revision 15.
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 of ASME Code Class 1 RPV Shell-to-Flange Weld FTSW-RV-01, and Head-to-Flange Weld FTHW-RV-18.
Licensee's Basis for Relief Request (as stated)
The limitation that reduces the amount of ultrasonic (UT) examination coverage for RPV Flange-to-Upper Shell Weld, FTSW-RV-01 is the vessel configuration at the flange. Attempting to perform supplemental examinations from the outside surface would require extensive surface preparation and result in unwarranted dose without an increase in the level of reliability, quality or safety.
The limitations for the RPV Flange-to-Head Weld, FTHW-RV-18 are due to the configuration of the flange directly adjacent to the weld and the vessel head lifting lugs. To gain additional coverage, the RPV would require design modifications which are not possible.
- 5 Licensee's Proposed Alternative Examination The licensee did not propose an alternative examination; however, it did perform the ASME Code-required examinations to the extent practical.
Staff Evaluation The ASME Code requires essentially 100 percent volumetric examination of pressure retaining welds in the RPV. However, the geometric configurations of the RPV shell-to-flange and flange-to-head welds, in addition to the location of the vessel head lifting lugs, limit the available coverage of the ASME Code inspection volume. In order to effectively increase the examination coverage area, the RPV flanges and vessel lifting lug components would require extensive design modifications or replacement. This would place a burden on the licensee; thus, examining essentially 100 percent of the ASME Code-required volumes is considered impractical.
As shown in the sketches and technical descriptions included in the licensee's submittals, examinations of RPV Flange-to-Upper Shell Weld FTSW-RV-01 and Flange-to-Head Weld FTSW-RV-18 have been performed to the extent practical, with the licensee obtaining coverage of 87.5 percent and 71.7 percent of the ASME Code-required inspection volumes, respectively.
For Weld FTHW-RV-01, the curvature of the flange restricts coverage of the ASME Code required volume. The FTHW-RV-01 UT examinations were conducted using 45-degree single and dual element longitudinal wave and 45-degree shear wave inspections, with equipment, procedures and personnel that were qualified by performance demonstration in accordance with the ASME Code,Section XI, Appendix VIII. Only one indication was detected; the indication was evaluated to be allowable per ASME Code Section IWB-3510.
Ultrasonic scanning on Flange-to-Head Weld FTSW-RV-18 was restricted by the RPV head lifting lugs located on the outside of the vessel and the design configuration of the weld, which allows access from the head side only. The UT examinations included O-degree longitudinal, and 45 and 60-degree shear wave inspections that encompassed most of the weld and base materials. No recordable indications were observed on this weld. In addition, the licensee completed an ASME Code-required magnetic particle surface examination for the RPV flange-to-head weld with no indications being detected.
The licensee has shown that it is impractical to meet the ASME Code-required 100 percent volumetric examination coverage for the subject welds due to their geometrical design and proximity of adjacent components. However, based on the volumetric coverage obtained, along with the full ASME Code-required surface examination completed on the flange-to-head weld, 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 to the extent practical provide reasonable assurance of the structural integrity of the subject welds.
- 6 3.3 Request for Relief 2R1-021. ASME Code.Section XI, Examination Category 8-0. Item 83.110. Full Penetration Welded Nozzles in Vessels ASME Code Requirement ASME Code,Section XI, Examination Category 8-0, Item 83.110 requires 100 percent vOlumetric examination, as defined by the ASME Code,Section XI, Figure IW8-2500-7 (a) through (d), as applicable, of full penetration ASME Code Class 1 nozzle-to-vessel welds on the pressurizer. ASME Code Case N-460, as an alternative approved for use by the NRC in RG 1.147, Revision 15, states that a reduction in examination coverage area due to component geometry or interference for any 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).
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 volumetric examinations for the ASME Code Class 1 pressurizer (PZR) nozzle-to-vessel welds listed in Table 3.4.1 below.
83.110 NTHW-08 Pressurizer Surge Nozzle-to-Head 66.00/0 83.110 NTHW-09 Pressurizer Spray Nozzle-to-Head 67.14%
83.110 NTHW-10 Pressurizer Safety Nozzle-to-Head 67.14%
83.110 NTHW-11 Pressurizer Safety Nozzle-to-Head 67.14%,
83.110 NTHW-12 Pressurizer Safety Nozzle-to-Head 67.14%
83.110 NTHW-13 Pressurizer Relief Nozzle-to-Head 67.14%
Licensee's 8asis for Relief Request (as stated)
The PZR nozzle-to-vessel welds require volumetric, examination from two sides of the weld to achieve 100 percent completion, but due to nozzle configurations of these components, UT examinations are limited to scanning primarily from the head side of the nozzle welds. The head-side examination of the surge nozzle is additionally limited due to permanent heater obstructions.
Licensee's Proposed Alternative Examination The licensee did not propose an alternative examination; however, it did perform the ASME Code-required examinations to the extent practical.
- 7 Staff Evaluation The ASME Code requires 100 percent volumetric examination of ASME Code Class 1 PZR nozzle-to-vessel welds. In addition, the ASME Code requires that the volumetric examination be conducted from both sides of these pressure retaining welds. However, the design configurations of the subject nozzle-to-vessel welds limit access for UT scanning, primarily to the head side of the welds. In order to effectively increase the examination coverage area, the nozzle-to-head welds would require extensive design modifications or replacement. This would place a burden on the licensee; thus, 100 percent ASME Code-required volumetric examinations are considered impractical.
As shown in the sketches and technical descriptions included in the licensee's submittals, examinations of the subject nozzle-to-vessel welds have been completed to the extent practical, with the licensee obtaining aggregate volumetric coverage ranging from approximately 66 to 67 percent of the ASME Code-required volumes (see Table 3.4.1 above).
The PZR nozzle-to-vessel welds in Table 3.4.1 are constructed of carbon steel material, with stainless steel inside diameter (ID) cladding. The welds on the subject nozzles extend the full thickness of tl1e PZR upper and/or lower head. These nozzles are of the "set-in" design, which essentially makes the welds concentric rings aligned parallel with the nozzle axes in the through-wall direction of the PZR head. This design geometry limits ASME Code-required UT angle beam examinations such that they must be performed primarily from the head side of the welds. Similarly, the PZR surge nozzle examination is also limited due to the close proximity of heater penetrations.
The UT examinations on the carbon steel PZR nozzle welds included O-degree longitudinal as well as 45 and 60-degree shear wave inspections from the head side.
The examination volume included the weld and base materials near the inside surface of the weld joint, which are typically the highest regions of stress, and where one would expect degradation sources to be manifested should they occur. All of the examinations were conducted with equipment, procedures, and personnel that were qualified by performance demonstration in accordance with the ASME Code,Section XI, Appendix VIII. No indications were recorded during these examinations.
Although the ultrasonic scans were primarily limited to the head side only, recent studies have found that inspections conducted through carbon steel are equally effective whether the ultrasonic waves have only to propagate through the base metal, or have to also propagate through the carbon steel weldment1. Therefore, it is expected that the ultrasonic techniques employed by the licensee would detect structurally significant flaws that might occur on either side of the subject welds due to the fine-grained carbon steel microstructures present.
The licensee has shown that it is impractical to meet the ASME Code-required 100 percent volumetric examination coverage for the subject nozzle-to-vessel welds due P. G. Heasler, and S. R. Doctor, 1996. Piping Inspection Round Robin, NUREG/CR-5068, PNNL-10475, U. S. Nuclear Regulatory Commission, Washington. DC.
- 8 to the nozzle designs and component obstructions. However, based on the vOlumetric 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, evidence of it would have been detected by the examinations that were performed. Furthermore, the staff determined that the examinations performed to the extent practical provide reasonable assurance of the structural integrity of the subject welds.
3.4 Request for Relief 2R1-022 ASME Code.Section XI. Examination Category 8-8. Item 82.40. Pressure Retaining Welds in Vessels Other than Reactor Vessels ASME Code Requirement ASME Code,Section XI, Examination Category 8-8, Item 82.40 requires essentially 100 percent volumetric examination, as defined by ASME Code,Section XI, Figure IW8-2500-6, of the length of ASME Code Class 1 Steam Generator (SG) primary side tubesheet-to-head welds. "Essentially 100 percent," as clarified by ASME Code Case N-460, is greater than 90 percent coverage of the examination volume, or surface area, as applicable. ASME Code Case N-460 has been approved for use by the NRC in RG 1.147, Revision 15.
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 of ASME Code Class 1 SG Primary Side Tubesheet-to-Head Weld II-SG-001 SGA-TSTHW-06-1.
Licensee's 8asis for Relief Request (as stated)
The limitation that reduces the amount of UT examination coverage for Tubesheet-to-Head Weld II-SG-001 SGA-TSTHW-06-1 is the vessel configuration at the flange and the four pedestal generator supports.
Attempting to perform supplemental examinations from the inside surface would result in unwarranted dose without an increase in the level of reliability, quality or safety.
To allow for complete examination coverage in accordance with the specified ASME Code requirements, steam generator modification or the replacement of components would be needed.
Licensee's Proposed Alternative Examination The licensee did not propose an alternative examination; however, it did perform the ASME Code-required examinations to the extent practical.
Staff Evaluation The ASME Code requires essentially 100 percent volumetric examination of the accessible length of SG primary side tubesheet-to-head weld. However, complete
- 9 examination of the SG primary side tubesheet-to-head weld is restricted by the interference of four lower lateral support pads. In order to gain greater access for inspection, and thereby increase the examination coverage area, the SG would require extensive design modifications. This would place a burden on the licensee; thus, examining essentially 100 percent of the ASME Code-required volume is considered impractical.
As shown in the sketches and technical descriptions included in the licensee's submittals, examinations of SG Primary Side Tubesheet-to-Head Weld II-SG-001 SGA-TSTHW-06-1 have been performed to the extent practical, with the licensee obtaining volumetric coverages of approximately 74.20 percent of the base metal and 70.11 percent of the weld material.
The four lower lateral support pads directly inhibit 100 inches (combined) of the 428-inch SG tubesheet-to-head weld length, which only leaves 328 inches available to be scanned. The UT examinations on the carbon steel SG weld included O-degree longitudinal as well as 45 and 60-degree shear wave inspections that encompassed most of the weld and base materials. All of the examinations were conducted with equipment, procedures, and personnel that were qualified by performance demonstration in accordance with the ASME Code,Section XI, Appendix VIII.
No unacceptable indications were recorded.
The licensee has shown that it is impractical to meet the ASME Code-required 100 percent volumetric examination coverage for the subject weld due to the design and proximity of other components. However, based on the volumetric coverage obtained, 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 to the extent practical provide reasonable assurance of the structural integrity of the subject weld.
3.5 Request for Relief 2R2-009. ASME Code,Section XI. Examination Category C-A. Item C1.10, Pressure Retaining Welds in Pressure Vessels ASME Code Requirement ASME Code,Section XI, Examination Category C-A, Item C1.1 0 requires essentially 100 percent volumetric examination, as defined by ASME Code,Section XI, Figure IWC-2500-1, of the length of selected ASME Code Class 2 pressure vessel circumferential shell welds. "Essentially 100 percent," as clarified by ASME Code Case N-460, is greater than 90 percent coverage of the examination volume, or surface area, as applicable. ASME Code Case N-460 has been approved for use by the NRC in RG 1.147, Revision 15.
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 of ASME Code Class 2
- 10 Residual Heat Removal (RHR) Heat Exchanger Circumferential Shell Weld II-RHR-01 RHRA-CSW-02.
Licensee's Basis for Relief Request (as stated)
Circumferential shell welds require volumetric examination from two sides of the weld in order to be 100 percent complete, but due to the restricted access caused by the flange-to-shell configuration and the flange bolting interference, UT examinations are limited. To meet these ASME Code requirements, heat exchanger modifications or the replacement of components would be needed.
Licensee's Proposed Alternative Examination The licensee performed a limited ASME Code-required UT examination of RHR Heat Exchanger Circumferential Shell Weld II-RHR-01 RHRA-CSW-02. A lO-degree %-Vee shear wave ultrasonic examination was also performed to supplement the ASME Code-required volumetric examination, although this examination is not included in the percent coverage calculations. Additionally, while not required by the ASME Code, a liquid penetrant (PT) surface examination was also performed.
Staff Evaluation The ASME Code requires essentially 100 percent volumetric examination of selected ASME Code Class 2 vessel circumferential shell welds. However, for RHR Heat Exchanger Circumferential Shell Weld II-RHR-01 RHRA-CSW-02, complete examinations are limited to one side of the weld due to the tapered scanning surface of the flange and flange bolting interference. In order to effectively increase the examination coverage area for this weld, the RHR heat exchanger would require extensive design modifications. This would place a burden on the licensee; thus, 100 percent ASME Code-required volumetric examinations are considered impractical.
As shown in the sketches and technical descriptions included in the licensee's submittals, examination of the RHR Heat Exchanger Circumferential Shell-to-Flange Weld II-RHR-01 RHRA-CSW-02 has been performed to the extent practical, with the licensee obtaining coverage of approximately 66.5 percent of the ASME Code-required inspection volume.
The RHR heat exchanger is fabricated from stainless steel. The licensee examined the subject weld from the shell side of the weld using a 45-degree ultrasonic shear wave inspection in order to achieve both circumferential and axial coverage along the weld length in areas not limited by the flange angle. To supplement the ASME Code-required volumetric examination, the licensee applied a lO-degree shear wave UT examination and a PT surface examination, although these supplemental examinations are not factored into the calculated volumetric coverage percentage of 66.5 percent. All of the examinations were conducted with equipment, procedures, and personnel that were qualified by performance demonstration in accordance with the ASME Code,Section XI, Appendix VIII. No recordable flaw indications were observed during these examinations.
- 11 The licensee has shown that it is impractical to meet the ASME Code-required 100 percent volumetric examination coverage for the subject weld due to the flange taper design and flange bolting obstructions. However, based on the volumetric coverage obtained with the examination techniques applied, and considering the augmented liquid penetrant examination, 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 to the extent practical provide reasonable assurance of the structural integrity of the subject weld.
3.6 Request for Relief 2R2-010, ASME Code,Section XI, Examination Category C-B, Item C2.21, Pressure Retaining Nozzle Welds in Vessels ASME Code Requirement ASME Code,Section XI, Examination Category C-B, Item C2.21 requires 100-percent surface and volumetric examination, as defined by ASME Code,Section XI, Figure IWC 2500-4 (a) or (b), as applicable, for ASME Code Class 2 nozzle-to-head welds. ASME Code Case N-460, as an alternative approved for use by the NRC in RG 1.147, Revision 15, states that a reduction in examination coverage area due to component geometry or interference for any 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).
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 of Boron Injection Tank (BIT)
Nozzle-to-Head Welds II-BIT-01 NTHW-03 and II-BIT-01 NTHW-04.
Licensee's Basis for Relief Request (as stated)
Per the applicable section of the ASME Code, nozzle-to-head welds require volumetric UT examination from two sides of the weld for 100 percent completion. However, due to the nozzle configurations of these components, UT examinations are limited to scanning primarily on the head side of the nozzle welds. To meet the ASME Code requirements, vessel modifications or the replacement of components would be needed.
Licensee's Proposed Alternative Examination The licensee did not propose an alternative examination; however, it did perform the ASME Code-required examinations to the extent practical.
Staff Evaluation The ASME Code requires 100 percent surface and volumetric examination of ASME Code Class 2 nozzle-to-head welds. However, for BIT Nozzle-to-Head
- 12 Welds 11-8IT-01 NTHW-03 and 11-8IT-01 NTHW-04, complete volumetric examinations are restricted by the nozzle configuration. In order to effectively increase the examination coverage area, the nozzle and/or vessel would require extensive design modifications or replacement. This would place a burden on the licensee; thus, 100 percent ASME Code-required volumetric examinations are considered impractical.
As shown in the sketches and technical descriptions included in the licensee's submittals, examinations of 81T Nozzle-to-Head Welds 11-8IT-01 NTHW-03 and 11-8IT-01 NTHW-04 have been performed to the extent practical, with the licensee obtaining coverage of approximately 77.14 percent of the ASME Code-required inspection volumes on these austenitic stainless steel welds.
UT examinations included a O-degree longitudinal as well as 45 and 50-degree shear wave inspections, oriented both parallel and perpendicular to the weld, as performed from the head side. These nozzles are of the "set-in" design, which essentially makes the welds concentric rings aligned parallel with the nozzle axes in the through-wall direction of the RPV shell. This design geometry limits ASME Code-required UT angle beam examinations such that they must be performed only from the shell side of the welds. All of the examinations were conducted with equipment, procedures, and personnel that were qualified by performance demonstration in accordance with the ASME Code,Section XI, Appendix VIII. No recordable indications were observed during these examinations. In addition, the licensee completed 100 percent of the ASME Code-required surface examination for the 81T nozzle-to-head welds with no recordable indications being detected.
The licensee has shown that it is impractical to meet the ASME Code-required 100 percent volumetric examination coverage for the subject welds due to the nozzle configuration. However, based on the volumetric coverage obtained, and the full surface examination coverage, it is reasonable to conclude that if significant service-induced degradation had occurred, evidence of it would be have been detected by the examinations that were performed. Furthermore, the staff determined that the examinations performed to the extent practical provide reasonable assurance of structural integrity of the subject welds.
3.7 Request for Relief 2R2-011, ASME Code,Section XI. Examination Category C-C, Item C3.30, Integral Attachments for Vessels, Piping. Pumps, and Valves ASME Code Requirement ASME Code,Section XI, Examination Category C-C, Item C3.30, requires 100-percent surface examination, as defined by ASME Code,Section XI, Figure IWC-2500-5, of integrally welded attachments to ASME Code Class 2 pumps. ASME Code Case N-460, as an alternative approved for use by the NRC in RG 1.147, Revision 15, states that a reduction in examination coverage area due to component geometry or interference for any 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).
- 13 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 surface examination of the charging safety injection pump integrally welded supports listed in Table 3.7.1 below.
C3.30 C3.30 C3.30 C3.30 II-CSIP-1 CSIP-A-WA1 II-CSIP-1 CSIP-A-WA2 II-CSIP-1 CSIP-A-WA3 II-CSIP-1 CSIP-A-WA4 Pump Support Feet Pump Support Feet Pump Support Feet Pump Support Feet 80.0%
75.0%
Licensee's Basis for Relief Request (as stated)
The Charging Safety Injection Pump integral welded attachments require 100 percent surface examination of the required areas of each welded attachment. However, due to the restricted access caused by the configuration of the components, structural support steel limits access to one side of the welded attachment. Therefore, 100 percent surface examinations are limited without implementing design modifications.
Licensee's Proposed Alternative Examination:
The licensee did not propose an alternative examination; however, it did perform the ASME Code-required examinations to the extent practical.
Staff Evaluation The ASME Code requires 100 percent surface examination of ASME Code Class 2 integral pump attachment welds. However, the design configurations of the subject integral pump attachment welds limit surface examinations due to partial inaccessibility caused by their design and proximity to structural steel. In order to effectively increase the examination coverage area, the integral attachment welds would require extensive redesign or modification. This would place a burden on the licensee; thus, 100 percent ASME Code-required surface examinations are considered impractical.
As shown in the sketches and technical descriptions included in the licensee's submittals, PT examinations of the subject integral attachment welds have been performed to the extent practical, with the licensee obtaining surface examination coverage ranging from approximately 75 to 82 percent of the ASME Code-requirement (see Table 3.7.1 above).
- 14 Interference for the surface examinations was caused by adjacent structural steel supports on the subject welds. In addition, on Weld II-CSIP-A-WA1 and Weld II.;CSIP-1 CSIP-A-WA4, further limitations were caused by the pump flange mating surface. All of the examinations were conducted with equipment, procedures, and personnel that were qualified by performance demonstration in accordance with the ASME Code,Section XI, Appendix VIII. No reportable indications were detected during these surface examinations.
The licensee has shown that it is impractical to meet the ASME Code-required 100 percent surface examination coverage for the subject welds due to the proximity of adjacent structural steel supports. However, based on the surface coverage obtained, it is reasonable to conclude that if significant service-induced degradation had occurred, evidence of it would be have been detected by the examinations that were performed.
Furthermore, the staff determined that the examinations performed to the extent practical provide reasonable assurance of the structural integrity of the subject welds.
4.0 CONCLUSION
S The staff has reviewed the licensee's submittals and concludes that ASME Code examination coverage requirements are impractical for the subject welds listed in RRs 2R1-019, 2R1-020, 2R1-021, 2R1-022, 2R2-009, 2R2-010, and 2R2-011. Furthermore, imposition of these ASME Code requirements would create a burden on the licensee. The staff further determined that based on the volumetric and surface coverage, if applicable, obtained during inspection of 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. In addition, the staff concluded that the examinations, as performed to the extent practical, provide reasonable assurance of the 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 will remain in compliance with the requirements of 10 CFR 50.55a subsequent to the granting of this relief. Therefore, the NRC staff grants relief for the subject examinations of the components contained in RRs 2R1-019, 2R1-020, 2R1-021, 2R1-022, 2R2-009, 2R2-010, and 2R2-011 for the second 10-year lSI interval at the Shearon Harris Nudear Plant, Unit 1.
The staff has further determined that granting RRs 2R1-019, 2R1-020, 2R1-021, 2R1-022, 2R2-009, 2R2-010, and 2R2-011 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 given 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 approved in the subject requests for relief remain applicable, including third-party review by the Authorized Nuclear Inservice Inspector.
Principal Contributor: T. McLellan, NRC Date: Ja.nua.ry 7, 2010
TABLE 1
SUMMARY
OF RELIEF REQUESTS SHEARON HARRIS NUCLEAR POWER PLANT, UNIT 1 Second 10-Year lSI Interval Relief Request Number TLR RR Sec.
System or Component Exam.
Category Item No.
Volume or Area to be Examined Required Method Licensee Proposed Alternative Relief Request Disposition 2R1-019 3.1 Pressure Retaining Welds in Reactor Vessel 8-A 81.11 81.21 100% of Class 1 RPV circumferential shell and head welds Volumetric Use volumetric coverage obtained Granted 10 CFR 50.55a(g)(6)(i) 2R1-020 3.2 Pressure Retaining Welds in Reactor Vessel 8-A 81.30 81.40 100% of Class 1 RPV flange to shell and flange to head welds VOlumetric and Surface Use volumetric coverage obtained Granted 10 CFR 50.55a(g)(6)(i) 2R1-022 3.3 Class 1 Pressure Retaining Welds in Steam Generator 8-8 82.40 100% of Class 1 SG tubesheet-to-head weld Volumetric Use volumetric coverage obtained Granted 10 CFR 50.55a(g)(6)(i) 2R1-021 3.4 Full Penetration Welded Nozzles in Pressurizer B-D B3.110 100% of Class 1 PZR nozzle to vessel welds Volumetric Use volumetric coverage obtained Granted 10 CFR 50.55a(g)(6)(i) 2R2-009 3.5 Class 2 Pressure Retaining Shell Welds in Vessels C-A C1.10 100% of Class 2 circumferential shell welds in residual heat removal heat exchanger Volumetric Use volumetric coverage obtained plus additional volumetric and surface examinations Granted 10 CFR 50.55a(g)(6)(i) 2R2-010 3.6 Pressure Retaining Nozzle Welds in Vessels C-B C2.21 100% of Class 2 boron injection tank nozzle to vessel welds Volumetric and Surface Use volumetric coverage obtained Granted 10 CFR 50.55a(g)(6)(i) 2R2-011 3.7 Integral Attachments for Vessels, Piping, and Pumps C-C C3.30 100% of Class 2 welded pump supports on charging safety injection pump Surface Use surface coverage obtained Granted 10 CFR
- 50. 55a(g)(6)(i)
C. Burton
- 2 The NRC staff's safety evaluation is enclosed. If you have any questions regarding this matter, please contact Marlayna Vaaler at (301) 415-3178.
Sincerely, IRA!
Thomas H. Boyce, Chief Plant Licensing Branch 11-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-400
Enclosure:
Safety Evaluation cc w/enclosure: Distribution via ListServ DISTRIBUTION:
PUBLIC RidsNrrPMShearonHarris RidsNrrDciCvib LPL2-2 R/F RidsNrrLACSola RidsRgn2MailCenter RidsNrrDorlLpl2-2 RidsOgcRp RidsAcrsAcnw_MailCTR TMclellan, NRR ADAMS Accession Number: ML093561419 NRR-028 OFFICE LPL2-2/PM LPL2-2/LA CVIB/BC LPL2-2/BC NAME MVaaler CSoia MMitchell*
TBoyce DATE 12/18/09 12/30/09 12/3/2009 1/7/2010
- by memo OFFICIAL RECORD COpy