ML082540887
| ML082540887 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 09/19/2008 |
| From: | Boyce T Plant Licensing Branch II |
| To: | Waldrep B Carolina Power & Light Co |
| Saba F, NRR/DORL/LPL2-2, 301-415-1447 | |
| References | |
| TAC MD8116, TAC MD8117 | |
| Download: ML082540887 (16) | |
Text
September 19, 2008 Mr. Benjamin Waldrep, Vice President Brunswick Steam Electric Plant Carolina Power & Light Company Post Office Box 10429 Southport, North Carolina 28461
SUBJECT:
BRUNSWICK STEAM ELECTRIC PLANT, UNITS 1 AND 2 - SAFETY EVALUATION OF RELIEF REQUEST ISI-03 FOR SNUBBER VISUAL EXAMINATION AND FUNCTIONAL TESTING RELATED TO THE FOURTH 10-YEAR INTERVAL INSERVICE INSPECTION PROGRAM FOR BRUNSWICK STEAM ELECTRIC PLANT, UNITS 1 AND 2 (TAC NOS. MD8116 AND MD8117)
Dear Mr. Waldrep:
By letter dated February 6, 2008, Carolina Power & Light Company (the licensee) submitted Relief Request (RR) ISI-03 for the fourth 10-year inservice inspection (ISI) and testing program for snubbers at Brunswick Steam Electric Plant (BSEP), Units 1 and 2. In response to the Nuclear Regulatory Commission (NRC) staffs request for additional information, the licensee submitted its response in letters dated June 26 and August 29, 2008. The fourth 10-year ISI interval began on May 11, 2008 and is scheduled to be completed by May 10, 2018.
The NRC staff has evaluated the submitted RR ISI-03 and concludes that the proposed alternative to use Technical Requirement Manual Section 3.21 for snubber visual inspection and functional testing provides an acceptable level of quality and safety. Therefore, pursuant to Title 10 of the Code of Federal Regulations, Section 50.55a(a)(3)(i), the NRC authorizes the proposed alternative for the fourth 10-year ISI interval for BSEP, Units 1 and 2.
The bases for the NRC staffs conclusion are contained in the enclosed Safety Evaluation. If you have any questions regarding this issue, please contact Farideh Saba at (301) 415-1447 or farideh.saba@nrc.gov.
Sincerely,
/RA/
Thomas H. Boyce, Chief Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-325 and 50-324
Enclosure:
Safety Evaluation cc w/encl: See next page
September 19, 2008 Mr. Benjamin Waldrep, Vice President Brunswick Steam Electric Plant Carolina Power & Light Company Post Office Box 10429 Southport, North Carolina 28461
SUBJECT:
BRUNSWICK STEAM ELECTRIC PLANT, UNITS 1 AND 2 - SAFETY EVALUATION OF RELIEF REQUEST ISI-03 FOR SNUBBER VISUAL EXAMINATION AND FUNCTIONAL TESTING RELATED TO THE FOURTH 10-YEAR INTERVAL INSERVICE INSPECTION PROGRAM FOR BRUNSWICK STEAM ELECTRIC PLANT, UNITS 1 AND 2 (TAC NOS. MD8116 AND MD8117)
Dear Mr. Waldrep:
By letter dated February 6, 2008, Carolina Power & Light Company (the licensee) submitted Relief Request (RR) ISI-03 for the fourth 10-year inservice inspection (ISI) and testing program for snubbers at Brunswick Steam Electric Plant (BSEP), Units 1 and 2. In response to the Nuclear Regulatory Commission (NRC) staffs request for additional information, the licensee submitted its response in letters dated June 26 and August 29, 2008. The fourth 10-year ISI interval began on May 11, 2008 and is scheduled to be completed by May 10, 2018.
The NRC staff has evaluated the submitted RR ISI-03 and concludes that the proposed alternative to use Technical Requirement Manual Section 3.21 for snubber visual inspection and functional testing provides an acceptable level of quality and safety. Therefore, pursuant to Title 10 of the Code of Federal Regulations, Section 50.55a(a)(3)(i), the NRC authorizes the proposed alternative for the fourth 10-year ISI interval for BSEP, Units 1 and 2.
The bases for the NRC staffs conclusion are contained in the enclosed Safety Evaluation. If you have any questions regarding this issue, please contact Farideh Saba at (301) 415-1447 or farideh.saba@nrc.gov.
Sincerely,
/RA/
Thomas H. Boyce, Chief Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-325 and 50-324
Enclosure:
Safety Evaluation cc w/encl: See next page Distribution:
PUBLIC LPL2-2 R/F RidsNrrDorlLpl2-2 RidsNrrPMFSaba RidsOgcRp RidsNrrLACSola (Hard Copy)
RidsAcrsAcnwMailCenter RidsRgn2MailCenter RidsNrrDorlDpr GBedi RidsNrrDciCptb ADAMS ACCESSION NO.: ML082540887
- By memorandum NRR-106 OFFICE LPL2-2/PM LPL2-2/LA CPTB/BC*
OGC LPL2-2/BC NAME FSaba CSola JMcHale RHolmes TBoyce DATE 9/15/08 9/15/08 09/08/08 9/19/08 9/19/08 OFFICIAL RECORD COPY
Carolina Power & Light Company Brunswick Steam Electric Plant Units 1 and 2 cc:
David T. Conley Associate General Counsel II -
Legal Department Progress Energy Service Company, LLC Post Office Box 1551 Raleigh, North Carolina 27602-1551 Mr. William M. Sue, Chairperson Brunswick County Board of Commissioners Post Office Box 249 Bolivia, North Carolina 28422 Resident Inspector U. S. Nuclear Regulatory Commission 8470 River Road Southport, North Carolina 28461 Mr. John H. ONeill, Jr.
Pillsbury Winthrop Shaw Pittman, LLP 2300 N Street NW.
Washington, DC 20037-1128 Ms. Beverly Hall, Section Chief Division of Radiation Protection N.C. Department of Environment and Natural Resources 3825 Barrett Dr.
Raleigh, North Carolina 27609-7721 Mr. Edward L. Wills, Jr.
Plant General Manager Brunswick Steam Electric Plant Carolina Power & Light Company Post Office Box 10429 Southport, North Carolina 28461-0429 Public Service Commission State of South Carolina Post Office Drawer 11649 Columbia, South Carolina 29211 Ms. Margaret A. Force Assistant Attorney General State of North Carolina Post Office Box 629 Raleigh, North Carolina 27602 Mr. Robert P. Gruber Executive Director Public Staff - NCUC 4326 Mail Service Center Raleigh, North Carolina 27699-4326 Director, Site Operations Brunswick Steam Electric Plant Carolina Power & Light Company Post Office Box 10429 Southport, North Carolina 28461-0429 Sandra Spencer, Mayor City of Southport 201 East Moore Street Southport, North Carolina 28461 Mr. Warren Lee Emergency Management Director New Hanover County Department of Emergency Management Post Office Box 1525 Wilmington, North Carolina 28402-1525 Mr. J. Paul Fulford Manager, Performance Evaluation and Regulatory Affairs PEB5 Carolina Power & Light Company Post Office Box 1551 Raleigh, North Carolina 27602-1551 Robert J. Duncan II Vice President, Nuclear Operations Progress Energy Post Office Box 1551 Raleigh, North Carolina 27602-1551 Brian C. McCabe Manager, Nuclear Regulatory Affairs Progress Energy Post Office Box 1551 Raleigh, North Carolina 27602-1551
Enclosure SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION FOURTH 10-YEAR INTERVAL INSERVICE EXAMINATION PROGRAM FOR SNUBBERS RELIEF REQUEST ISI-03 BRUNSWICK STEAM ELECTRIC PLANT, UNITS 1 AND 2 DOCKET NUMBERS 50-325 AND 50-324
1.0 INTRODUCTION
By letter dated February 6, 2008, Carolina Power & Light Company (the licensee) submitted Relief Request (RR) ISI-03 for the fourth 10-year inservice inspection (ISI) and testing program for snubbers at Brunswick Steam Electric Plant (BSEP), Units 1 and 2. In response to the Nuclear Regulatory Commission (NRC) staffs request for additional information (RAI), the licensee submitted its response in letters dated June 26 and August 29, 2008. The licensee requested relief from certain ISI and examination requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (ASME Code)Section XI, 2001 Edition through 2003 Addenda, Article IWF-5000.
Article IWF-5000 references ASME/American Nuclear Standards Institute (ANSI) Code for Operation and Maintenance of Nuclear Power Plants (OM), Part 4 (OM-4), 1987 Edition with OMa-1988 Addenda. The licensee proposed to perform the snubber surveillance activities using BSEP, Units 1 and 2, Technical Requirement Manual (TRM), Section 3.21, Snubbers. This relief request is for the fourth 10-year ISI and testing program for snubbers at BSEP, Units 1 and 2. The fourth 10-year ISI interval began on May 11, 2008 and is scheduled to be completed by May 10, 2018.
2.0 REGULATORY EVALUATION
The ISI of ASME Code Class 1, 2, and 3 components shall be performed in accordance with Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, of the ASME Code and applicable addenda as required by Title 10 of the Code of Federal Regulations (10 CFR) Section 50.55a(g), except where specific written relief has been granted by the Nuclear Regulatory Commission (NRC or the Commission), pursuant to 10 CFR 50.55a(g)(6)(i).
Section 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 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 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), 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 BSEP Units 1 and 2 fourth 10-year ISI interval is the 2001 Edition up to and including the 2003 Addenda.
3.0 TECHNICAL EVALUATION
3.1 Relief Request ISI-03 3.1.1 Components for Which Relief is Requested All BSEP, Units 1 and 2 safety-related ASME Code Class 1, 2 and 3 snubbers.
3.1.2 Code Requirements The ASME Code,Section XI, paragraph IWF-1220, Snubber Inspection Requirements, requires that the ISI requirements for snubbers be in accordance with the requirements of Article IWF-5000.
Paragraphs IWF-5200(a) and IWF-5300(a) require that snubber preservice and inservice examinations be performed in accordance with OM-4, using the VT-3 visual examination method described in paragraph IWA-2213.
Paragraphs IWF-5200(b) and IWF-5300(b) require that snubber preservice and inservice tests be performed in accordance with OM-4.
Paragraphs IWF-5200(c) and IWF-5300(c) require that integral and nonintegral attachments for snubbers, including lugs, bolting, pins, and clamps, be examined in accordance with the requirements of Subsection IWF.
3.1.3 Licensee=s Proposed Alternative The licensee proposes to use BSEP, Units 1 and 2, TRM Section 3.21, Snubbers, to perform visual examinations and functional testing of ASME Code Class 1, 2 and 3 snubbers in lieu of meeting ASME Code,Section XI requirements.
3.1.4 Licensee=s Basis for Requesting Relief BSEP, Units 1 and 2, TRM Section 3.21, Snubbers contains specifically developed and approved visual inspection and functional testing requirements for the snubbers at BSEP.
Generic Letter (GL) 90-09, Alternative Requirements for Snubber Visual Inspection Intervals and Corrective Actions, dated December 11, 1990, was issued to reduce the burden placed on utilities by the previous visual examination schedule requirements. The BSEP, Units 1 and 2, TRMs have incorporated these recommendations.
The overlap of the visual examination program required by the ASME Code,Section XI and the existing TRM snubber program for ISI classified snubbers presents an unnecessary redundancy without a compensating increase in the level of quality and safety. For this reason, this request is to continue using the alternative requirements outlined in the TRM snubber program.
The BSEP TRM snubber program, Section 3.21, provides a comprehensive program for visual examination and functional testing requirements of safety related and non-safety related snubbers. This program was implemented during the previous inspection interval and has been demonstrated to provide an acceptable level of quality and safety.
In addition, the TRM snubber program provides for a level of quality and safety equal to or greater than that of the requirements specified in Article IWF-5000 (i.e., OM-4). For example, OM-4 provides for failure mode grouping of snubbers which fail visual examination, meaning only those snubbers identified as being in that group would require shortened inspection intervals. Under the TRM snubber program, all snubbers in the population would be placed in a shortened inspection interval. As such, the TRM snubber program is more conservative in corrective action than the OM-4 requirements.
The functional test plan required by OM-4 also includes failure mode groups. The use of failure mode grouping is required even for a single failure, and in some cases allows for the failed snubber to be reclassified as acceptable with no further testing. This test plan is not conservative for the large snubber population which exists at BSEP (i.e., approximately 500 snubbers per unit) when compared to the TRM snubber program. The TRM snubber program requires supplemental testing for all failures until the desired confidence level is assured, with no allowances to reclassify failed snubbers.
Based on the above, the licensee has concluded that an equivalent level of quality and safety can be achieved by the continued implementation of the TRM snubber program. This time-proven program for conducting examinations and tests will continue to provide confidence in snubber operability while preventing plant personnel from receiving excessive radiation exposure. For these reasons, authorization is requested to continue using the alternative requirements outlined in the TRM snubber program.
3.1.5 NRC Staff Evaluation of Relief Request ISI-03 The licensee requested relief from the requirements of the ASME Code,Section XI, paragraphs IWF-5200(a) and (b), and IWF-5300(a) and (b). The licensee proposed that the inservice visual examinations and functional testing of ASME Code, Class 1, 2 and 3 snubbers be performed in accordance with the requirements of the BSEP, Units 1 and 2, TRM Section 3.21, Snubbers, in lieu of meeting the requirements in the ASME Code,Section XI, paragraphs IWF-5200(a) and (b), and IWF-5300(a) and (b).
The applicable edition of Section XI of the ASME Code for the BSEP, Units 1 and 2 fourth 10-year ISI interval is the 2001 Edition through 2003 Addenda. The ASME Code,Section XI, paragraphs IWF-5200(a), and (b), and IWF-5300(a), and (b) reference OM-4, 1987 Edition with OMa-1988 Addenda.
ASME Code,Section XI, paragraphs IWF-5200(a) and IWF-5300(a) require that snubber preservice and inservice examinations be performed in accordance with OM-4, using the VT-3 visual examination method described in paragraph IWA-2213. Paragraphs IWF-5200(b) and IWF-5300(b) require that snubber preservice and inservice tests be performed in accordance with OM-4.
Paragraphs IWF-5200(c) and IWF-5300(c) require that integral and non-integral attachments for snubbers, including lugs, bolting, pins, and clamps, be examined in accordance with Subsection IWF. In a response to an RAI, the licensee states that the non-destructive examination procedures are written to meet the requirements of the ASME Section XI, IWF-5000. Snubbers are visually inspected in accordance with plant procedure NDEP-0613, VT-3 Visual Examination of Nuclear Power Plant Components. Appendix III of NDEP-0613, paragraph 3.8.11, describes the examination boundary for snubber inspections, which includes integral and non-integral attachments for snubbers, including lugs, bolting, pins, and clamps.
The licensee states that the repair and replacement requirements of paragraph IWF-5400 are met with the use of plant procedure 0ENP-16.15, Administrative Procedure for Component Support and Snubber Program.
ASME Section XI, Table IWA-1600-1 states that OM-4 shall be of Edition 1987 with OMa-1988 Addenda. OM-4 specifies the requirements for visual examination (paragraph 2.3) and functional testing (paragraph 3.2). The licensee proposes to use BSEP TRM Section 3.21 for inservice visual examination and functional testing of all safety-related snubbers. A visual inspection is the observation of the condition of installed snubbers to identify those that are damaged, degraded, or inoperable as caused by physical means, leakage, corrosion, or environmental exposure. To verify that a snubber can operate within specific performance limits, the licensee performs functional testing that typically involves removing the snubber and testing it on a specially designed stand or bench. The performance of visual examinations is a separate process that complements the functional testing program and provides additional confidence in snubber operability.
BSEP, Units 1 and 2 TRM Section 3.21 incorporates GL 90-09, AAlternative Requirements for Snubber Visual Inspection Intervals and Corrective Actions.@ GL 90-09 acknowledges that the visual inspection schedule (as contained in OM-4) is excessively restrictive and that licensees with large snubber populations have spent a significant amount of resources and have subjected plant personnel to unnecessary radiological exposure to comply with the visual examination requirements. GL 90-09 states that its alternative schedule for visual inspection provides the same confidence level as that provided by OM-4.
TRM Section 3.21 defines inservice examination requirements: (1) visual examination; (2) visual examination interval frequency; (3) method of visual examination; (4) subsequent examination intervals; and (5) inservice examination failure evaluation. Inservice operability testing requirements are also defined: (1) inservice operability or functional test; (2) initial snubber sample size; (3) additional sampling; (4) failure evaluation; (5) test failure mode groups; and (6) corrective actions for the 10 percent sample, 37 sample, and 55 sample plans that are similar to those provided by OM-4. OM-4 requirements and TRM Section 3.21 criteria are compared and summarized in the following table and followed by a detailed review:
Criteria ASME/ANSI OM Part 4 -1987 through OMa-1988 Addenda Brunswick Steam Electric Plant, Units 1 and 2, TRM Section 3.21 Inservice Examination
- 1.
Visual Examination Paragraph 2.3.1.1, Visual Examination, states that snubber visual examinations shall identify impaired functional ability due to physical damage, leakage, corrosion, or degradation.
TRM 3.21, Test Requirements (TR) 3.21.2, requires that visual inspections shall verify that (1) the snubber has no indications of damage or impaired operability; (2) attachments to the foundations or supporting structure are functional; and (3) fasteners for the snubber attachment to the component and to the snubber anchorage are functional.
- 2.
Visual Examination Interval Frequency Paragraph 2.3.2.2 provides visual examination interval frequency.
TRM Table 3.21-1 provides snubber visual inspection interval frequency. These visual inspection interval frequency requirements are similar to those contained in NRC GL 90-09.
- 3.
Method of Visual Examination IWF-5200(a) and IWF-5300(a) require use of the VT-3 visual examination method described in IWA-2213.
The licensee states that snubber preservice and inservice visual examinations are performed in accordance with the plant procedure NDEP-0613. The NDEP-0613, VT-3 Visual Examination of Nuclear Power Plant Components, includes all of the requirements of IWA-2213 for both preservice and inservice examination.
- 4.
Subsequent Examination Intervals Paragraph 2.3.2 provides guidance for inservice examination intervals based on the number of unacceptable snubbers discovered.
TRM Table 3.21-1 provides a snubber visual inspection interval based on the number of unacceptable snubbers discovered. These requirements are similar to those contained in NRC GL 90-09.
- 5.
Inservice Examination Failure Evaluation Paragraph 2.3.4 states that snubbers not meeting examination and acceptance criteria shall be evaluated to determine the cause of unacceptability.
TRM Table 3.21-1, Note (g), states that snubbers which appear inoperable as a result of visual inspections shall be classified as unacceptable and may be reclassified acceptable for the purpose of establishing the next visual inspection interval, provided Criteria ASME/ANSI OM Part 4 -1987 through OMa-1988 Addenda Brunswick Steam Electric Plant, Units 1 and 2, TRM Section 3.21 that : (1) the cause of the rejection is clearly established and remedied for that particular snubber and for other generically susceptible snubbers, and (2) the affected snubber is functionally tested in the as-found condition and determined operable per the acceptance criteria of TR 3.21.3.c.
Inservice Operability Test
- 1.
Inservice Operability Test Requirements Paragraph 3.2.1.1, Operability Test, states that snubber operational readiness tests shall verify activation, release rate, and breakaway force or drag force by either an in-place or bench test.
TR 3.21.3.c, states that the snubber functional test is to verify (1) activation (restraining action) achieved within specified range in both tension and compression; (2) snubber bleed rate, or release rate where required, is present in both tension and compression, within the specified range; (3) where required, the force required to initiate or maintain motion is within the specified range in both directions of travel; and (4) for snubbers specifically required not to displace under continuous load, the ability to withstand load without displacement. The licensee states that generally snubbers shall be functionally tested either in-place or in a bench test.
- 2.
Snubber Sample size Paragraph 3.2.3 states that each defined test plan group shall use either a 10 percent sampling plan; a 37 testing sample plan; or a 55 testing sample plan during each refueling outage.
TR 3.21.3.a, states that snubber shall be functionally tested using the following sample plans: (1) at least 10 percent of the total of each type of snubber; or (2) a representative sample of each type snubber using TRM Figure 3.21-1 (37 snubbers testing sample plan);
or (3) a representative sample of 55 snubbers of each type. The licensee=s 10 percent testing sample, 37 testing sample, and 55 testing sample plans meet the requirements as specified in OM-4.
Criteria ASME/ANSI OM Part 4 -1987 through OMa-1988 Addenda Brunswick Steam Electric Plant, Units 1 and 2, TRM Section 3.21
- 3.
Additional Sampling (a) 10 Percent Testing Sample Plan:
Paragraph 3.2.3.1(b) states that for any snubber(s) determined to be unacceptable as a result of testing, an additional sample of at least one-half the size of the initial sample lot shall be tested.
(b) 37 or 55 Testing Sample Plans:
Paragraph 3.2.3.2(b) states that for any snubber(s) determined to be unacceptable as a result of testing, an additional random sample of at least one-half the size of the initial sample lot shall be tested until the total number tested is equal to the initial sample size multiplied by the factor (1+C/2), where C is total number of snubbers found to be unacceptable. If the 37 plan is selected, initial and any additional testing shall be in accordance with Figure 1 of the OM-4.
(a) 10 Percent Testing Sample Plan:
TR 3.21.3.a(1), requires that for each snubber of that type that does not meet the functional test acceptance criteria of TR 3.21.3.c, an additional 10 percent of that type of snubber shall be tested.
(b) 37 Testing Sample Plan:
The licensee states that TR 3.21.3.a(2) requirements are the same as of the OM-4 Code.
(c) 55 Testing Sample Plan:
The licensee states that TR 3.21.3.a(3) requirements are the same as of the OM-4 Code.
(Detailed evaluation is provided later in Item 3, Additional Sampling)
- 4.
Inservice Operability Failure Evaluation Paragraph 3.2.4.1 states that snubbers not meeting the operability testing acceptance criteria in paragraph 3.2.1 shall be evaluated to determine the cause of the failure.
TR 3.21.3.b, states that an engineering evaluation shall be made of each failure to meet the functional test acceptance criteria to determine the cause of the failure. The results of this evaluation shall be used, if applicable, in selecting snubbers to be tested in an effort to determine the operability of other snubbers, irrespective of type, which may be subject to the same failure mode.
- 5.
Test Failure Mode Groups Paragraph 3.2.4.2 states that unacceptable snubber(s) shall be categorized into failure mode group(s). A test failure mode group(s) shall include all unacceptable snubbers that have The licensee states that the failure mode grouping is a method to determine the extent of condition of failure, and the population or grouping for sample expansion.
Failure mode grouping is not Criteria ASME/ANSI OM Part 4 -1987 through OMa-1988 Addenda Brunswick Steam Electric Plant, Units 1 and 2, TRM Section 3.21 a given failure mode, and all other snubbers subject to the same failure mode.
incorporated into the TRM; however, plant procedures do address determining the extent of condition and determining failure grouping for sample expansion.
(Detailed evaluation is provided later in Item 5, Test Failure Mode Groups)
- 6.
Corrective Actions for 10 Percent Testing Sample Plan or 37 Testing Sample Plan or 55 Testing Plan Paragraphs 3.2.5.1 and 3.2.5.2 states that unacceptable snubbers shall be repaired, modified, or replaced.
The licensee states that all the snubbers that are considered unsatisfactory for functional testing shall be repaired or replaced, as required in plant procedure 0ENP-16.15. The replacement snubbers and repaired snubbers (where the repair may have affected the functional test result) shall be functionally tested prior to installation.
Inservice Examination Requirements (1)
Visual Examination TRM TR 3.21.2, requires that visual inspections shall verify that (1) the snubber has no indications of damage or impaired operability; (2) attachments to the foundations or supporting structure are functional; and (3) fasteners for the snubber attachment to the component and to the snubber anchorage are functional. The visual examination per TR 3.21.2.c verifies visible indication of damage or impaired operability of snubbers as well as its attachments and anchorages. OM-4, paragraph 2.3.1.1, requires snubber visual examinations to identify impaired functional ability due to physical damage, leakage, corrosion, or degradation. TRM 3.21 snubber visual examination requirements are considered to be equivalent to snubber visual examination requirements of OM-4 paragraphs 2.3.1.1. Therefore, this alternative provides an acceptable level of quality and safety.
(2)
Visual Examination Interval Frequency TRM Table 3.21-1 provides snubber visual inspection interval frequency requirements which are different than the OM-4 visual inspection interval requirements. Table 3.21-1 incorporates the visual inspection interval frequency as specified in GL 90-09, AAlternative Requirements for Snubber Visual Inspection Intervals and Corrective Actions.@ GL 90-09 acknowledges that the visual inspection interval frequency (as contained in OM-4) is excessively restrictive and that licensees with large snubber populations have spent a significant amount of resources and have subjected plant personnel to unnecessary radiological exposure to comply with the visual examination requirements. GL 90-09 states that its alternative schedule (interval frequency) for visual inspection provides the same confidence level as that provided by OM-4. Therefore, this alternative provides an acceptable level of quality and safety.
(3)
Method of Visual Examination IWF-5200(a) and IWF-5300(a) require that preservice and inservice examination be performed in accordance with OM-4, using the VT-3 visual examination method described in IWA-2213.
IWA-2213 states that VT-3 examinations are conducted to determine the general mechanical and structural condition of components and their supports by verifying parameters such as clearance, settings, and physical displacements; and to detect discontinuities and imperfections, such as loss of integrity at bolts and welded connections, loose or missing parts, debris, corrosion, wear, or erosion. VT-3 includes examinations for conditions that could affect operability or functional adequacy of snubbers and constant load and spring type supports.
TRM TR 3.21.2, requires that visual inspections shall verify that (a) the snubber has no visible indications of damage or impaired operability; (b) attachments to the foundation or supporting structure are secure; and (c) fasteners for the attachment of the snubber to the component and to the snubber anchorage are secure.
The licensee states that plant procedure 0ENP-16.15, Administrative Procedure for Components Support and Snubber Program, describes the requirements for visual inspection of snubbers. The plant procedure paragraph 5.1.3 details the requirements for visual inspection, and states that Components supports are visually examined in accordance with the requirements of ASME Section XI VT-3 method. The examinations are performed in accordance with the procedure NDEP-0613. NDEP-0613, VT-3 Visual Examination of Nuclear Power Plant Components, includes all of the requirements of IWA-2213 for both preservice and inservice examination.
The intent and scope of Brunswick TRM visual examination requirements are equivalent to the OM-4 VT-3 examination requirements. Therefore, the NRC staff finds the licensees method of snubber visual inspection provides an acceptable level of quality and safety and is acceptable.
(4)
Subsequent Examination Intervals TRM Table 3.21-1 establishes subsequent snubber visual inspection intervals based on the number of unacceptable snubbers discovered, in lieu of OM-4 paragraph 2.3.2 requirements.
These requirements are equivalent to the guidance provided in GL 90-09, which has been approved for use by the NRC. Therefore, the NRC staff finds that the subsequent examination intervals contained in TRM Table 3.21-1 provide an acceptable level of quality and safety and is acceptable.
(5)
Inservice Examination Failure Evaluation OM-4, paragraph 2.3.4.1 requires that snubbers not meeting examination criteria be evaluated to determine the cause of unacceptability. Paragraph 2.3.4.2 states that snubbers found unacceptable may be tested in accordance with the requirements of paragraph 3.2. TRM Table 3.21-1, Note (g), states that snubbers which appear inoperable as a result of visual inspections shall be classified as unacceptable and may be reclassified acceptable for the purpose of establishing the next visual inspection interval, provided that : (1) the cause of the rejection is clearly established and remedied for that particular snubber and for other generically susceptible snubbers, and (2) the affected snubber is functionally tested in the as-found condition and determined operable per the acceptance criteria of TR 3.21.3.c.
The licensee program is considered to be equivalent to the requirements of OM-4. Therefore, the NRC staff finds that the TRM=s inservice examination failure evaluation requirements provide an acceptable level of quality and safety.
Inservice Operability Testing Requirements (1)
Inservice Operability Test The licensee states that generally snubbers shall be functionally tested either in-place or in a bench test. TR 3.21.3.c states that the snubber functional test is to verify (1) activation (restraining action) achieved within specified range in both tension and compression; (2) snubber bleed rate, or release rate where required, is present in both tension and compression, within the specified range; (3) where required, the force required to initiate or maintain motion is within the specified range in both directions of travel; and (4) for snubbers specifically required not to displace under continuous load, the ability to withstand load without displacement. OM-4, paragraph 3.2.1.1, Operability Test, states that snubber operational readiness tests verify activation, release rate, and breakaway force or drag force by either an in-place or bench test. The staff finds that the TRM requirements are considered to be equivalent to the snubber operability test requirements of OM-4 paragraph 3.2.1. Therefore, the TRM functional test requirements provide an acceptable level of quality and safety.
(2)
Snubber Sample Size TR 3.21.3.a, states that snubber shall be functionally tested of a representative sample of each type (snubbers of the same design and manufacturer, irrespective of capacity) of snubber using the following sample plans: (1) at least 10 percent of the total population of a snubber type; or (2) a representative sample of each type snubber shall be tested in accordance with TRM Figure 3.21-1 (equivalent to 37 snubbers testing sample plan); or (3) a representative sample of 55 snubbers of each type. The licensees 10 percent testing sample, 37 testing sample, and 55 testing sample plans are similar to the sample plans requirements as specified in OM-4. As a result, the numbers of snubbers tested during outages are considered to be equivalent to the OM-4 requirements. Therefore, the TRM requirements for snubber sample size provide an acceptable level of quality and safety.
(3)
Additional Sampling (a)
For 10 Percent Testing Sample Plan TRM TR 3.21.3.a(1) requires that for each snubber of the type that does not meet the functional test acceptance criteria of TR 3.21.3.c, an additional 10 percent of that type of snubber shall be tested. OM-4, paragraph 3.2.3.1(b), requires that an additional sample size must be at least one-half the size of the initial sample size of the Adefined test plan group@ of snubbers. That is, for a 10 percent sample program, an additional 5 percent of the same type of snubber in the overall population would need to be tested. Therefore, TR 3.21.3.a requirements for additional sampling of 10 percent (instead of 5 percent as required by the OM-4) when using the 10 percent testing sample plan are considered acceptable.
(b)
For 37 testing sample plan OM-4, paragraph 3.2.3.2(b) states that for any snubber(s) determined to be unacceptable as a result of testing, an additional random sample of at least one-half the size of initial sample lot shall be tested until the total number tested (N) is equal to the initial sample size multiplied by the factor 1+ C/2, where C is total number of snubbers found to be unacceptable. The testing of additional samples is also required for snubbers determined to be unacceptable in any additional test. For the 37 sample plan, initial and any additional testing shall be in accordance with Figure C1 of the Appendix C of OM-4. The 37 sample plan, has an accept and a reject line (Figure C1). The accept line is governed by, an equation, N = 37(1 + C/2), and the reject line is governed by N = 37(-1 + C/2). Points are plotted only at the end of a lots testing. If the point plotted ever falls above the reject line, all snubbers of that group must be tested. The acceptance and rejection criteria of the TRM TR 3.21.3.a(2) and Figure 3.21-1, Snubber Functional Test Sample Plan 2 are same as of Figure C1 of the Appendix C of the OM-4.
Therefore, TRM requirements for additional sampling when using the 37 testing sample plan are considered acceptable.
(c)
For 55 testing sample plan OM-4, paragraph 3.2.3.2(b) states that for any snubber(s) determined to be unacceptable as a result of testing, an additional random sample of at least one-half the size of the initial sample lot shall be tested until the total number tested (N) is equal to the initial sample size multiplied by the factor 1+ C/2, where C is total number of snubbers found to be unacceptable. The testing of additional samples is also required for snubbers determined to be unacceptable in any additional test. The 55 sample plan only has an accept line, which is governed by an equation, N = 55(1 + C/2). Results for each snubber in the lot shall be plotted as soon as it is tested. If the point plotted falls on or below the accept line, testing of that group may be discontinued. If the point falls above the accept line, all snubbers of that group must be tested. The 55 testing sample plan criteria of the TRM TR 3.21.3.a(3) are similar to the requirements of the OM-4.
Therefore, TS SR requirements for additional sampling when using the 55 testing sample plan are considered acceptable.
(4)
Inservice Operability Failure evaluation OM-4 paragraph 3.2.4.1 requires that snubbers not meeting the operability testing acceptance criteria in paragraph 3.2.1 shall be evaluated to determine the cause of the failure. The cause of failure evaluation requires a review of information related to other unacceptable snubbers and a determination of whether other snubbers of similar design would require further examination.
TR 3.21.3.b, states that an engineering evaluation shall be made of each failure to meet the functional test acceptance criteria to determine the cause of the failure. The results of this evaluation shall be used, if applicable, in selecting snubbers to be tested in an effort to determine the operability of other snubbers, irrespective of type, which may be subject to the same failure mode. Therefore, the NRC staff finds that the TRM requirements related to inservice operability failure evaluation are considered to be equivalent to the OM-4 requirements.
(5)
Test Failure Mode Groups OM-4 paragraph 3.2.4.2 requires that unacceptable snubber(s) be categorized into failure mode group(s). A test failure mode group shall include all unacceptable snubbers that have a given failure mode, and all other snubbers subject to the same failure mode. The licensee states that the failure mode grouping is a method to determine the extent of condition of failure, and the population or grouping for sample expansion. Failure mode grouping in not incorporated into the TRM; however, plant procedures do address determining the extent of condition and determining failure grouping for sample expansion. The occurrence of unacceptable snubbers is documented by the Action Request in the Corrective Action Program. The licensee further states that its plant procedure 0ENP-16.15, Administrative Procedure for Component Support and Snubber Program, addresses the evaluation and the cause of failure for snubbers which do not meet acceptance criteria. Paragraph 5.2.3.3 of this procedure states:
Snubbers which fail the functional test acceptance criteria, shall be repaired or replaced. In addition, an Action Request shall be initiated for each failure which will drive an evaluation to determine the cause of failure and corrective actions to be taken. The result of this evaluation shall be used, if applicable, in the selection of additional snubbers to be tested that may subject to the same type of failure. The selection of additional snubbers for testing, which are subject to the same type of failure, fulfills the requirements for unacceptable snubbers to be categorized into test failure mode groups.
The BSEP TRM does not specifically address Failure Mode Groups. However, the plant procedure 0ENP-16.15 accomplishes the same intent as Failure Mode Grouping. Therefore, the TRM requirements with implementing procedures are considered to be equivalent to the OM-4 requirements, and are acceptable.
(6)
Inservice Operability Testing Corrective Actions for 10 percent sample or 37 sample plan or 55 sample plan OM-4, paragraphs 3.2.5.1 and 3.2.5.2 require that unacceptable snubbers be adjusted, repaired, modified, or replaced. The licensee states that all the snubbers that are considered unsatisfactory for functional testing shall be repaired or replaced, as required in plant procedure 0ENP-16.15. All repaired or replaced snubbers are visually inspected, once installed, prior to return to service. The replacement snubbers and repaired snubbers (where the repair may have affected the functional test result) shall be functionally tested prior to installation. Therefore, the NRC staff finds that the TRM requirements, with implementing procedure corrective actions associated with unacceptable snubbers at BSEP, are considered to be equivalent to the OM-4 requirements.
Based on the above discussions, the staff finds that snubber inservice visual examinations and functional testing, conducted in accordance with TRM 3.21, provide reasonable assurance of snubber operability and provide a level of quality and safety equivalent to that of the ASME Code,Section XI, Subarticles IWF-5200(a) and (b), and IWF-5300(a) and (b). Therefore, the staff finds the licensees proposed alternative provides an acceptable level of quality and safety with respect to snubber inservice visual inspection and functional testing.
4.0 CONCLUSION
Based on the information provided, the staff concludes that the proposed alternative to use TRM 3.21 for snubbers inservice visual inspection and functional testing activities provides an acceptable level of quality and safety. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), the licensee=s proposed alternative is authorized for the BSEP Units 1 and 2 fourth 10-year ISI and testing interval.
5.0 REFERENCES
t
- 1. U.S. Code of Federal Regulations, Domestic Licensing of Production and Utilization Facilities, Part 50, Chapter I, Title 10, AEnergy,@ Section 50.55a, Codes and standards.
- 2. Generic Letter (GL) 90-09, AAlternative Requirements for Snubber Visual Inspection Intervals and Corrective Actions,@ dated December 11, 1990.
- 3. American Society of Mechanical Engineers, Boiler and Pressure Vessel Code,Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components.
- 4. American Society of Mechanical Engineers, Operation and Maintenance Code, Inservice Testing of Nuclear Power Plant Components.
- 5. Technical Requirement Manuals, Brunswick Steam Electric Plant, Units 1 and 2.
- 6. Letter, Progress Energy Carolinas, Inc., to NRC, Brunswick Steam Electric Plant, Units 1 and 2, Docket No. 50-325 and 50-324/License Nos. DPR-71 and DPR-62, Relief Requests Associated with the Fourth 10-Year Inservice Inspection (ISI) Interval dated February 6, 2008.
- 7. Letter, Progress Energy Carolinas, Inc., to NRC, Brunswick Steam Electric Plant, Units 1 and 2, Docket No. 50-325 and 50-324/License Nos. DPR-71 and DPR-62, Response to Request for additional Information Regarding Relief Request ISI-03 for the Fourth 10 Year Inservice Inspection (ISI) Interval dated June 26, 2008 (TAC Nos. MD8116 and MD8117).
- 8. Letter, Progress Energy Carolinas, Inc., to NRC, Brunswick Steam Electric Plant, Units 1 and 2, Docket No. 50-325 and 50-324/License Nos. DPR-71 and DPR-62, Response to Request for additional Information Regarding Relief Request ISI-03 for the Fourth 10 Year Inservice Inspection (ISI) Interval dated August 29, 2008 (TAC Nos. MD8116 and MD8117).
Principal Contributors: Gurjendra Bedi Date: September 19, 2008