ML072820108

Request for Relief for Snubber Visual Examination and Functional Testing Related to the Third 10-year Interval Inservice Inspection Program

ML072820108
Person / Time
Site:	Catawba
Issue date:	10/31/2007
From:	Marinos E NRC/NRR/ADRO/DORL/LPLII-1
To:	Morris J Duke Power Co
Stang J, NRR/DORL 415-1345
References
TAC MD4657
Download: ML072820108 (16)

Text

October 31, 2007 Mr. J. R. Morris Site Vice President Catawba Nuclear Station Duke Power Company LLC 4800 Concord Road York, SC 29745

SUBJECT:

CATAWBA NUCLEAR STATION, UNIT 2, RELIEF 07-CN-003 FOR SNUBBER VISUAL EXAMINATION AND FUNCTIONAL TESTING RELATED TO THE THIRD 10-YEAR INTERVAL INSERVICE INSPECTION AND INSERVICE TESTING PROGRAMS (TAC NO. MD4657)

Dear Mr. Morris:

By letter dated February 26, 2007, Duke Power Company LLC (the licensee), submitted Relief Request No. 07BCN-003, for its third 10-year interval inservice inspection (ISI) and inservice testing (IST) programs for snubbers at Catawba Nuclear Station, Unit 2 (Catawba Unit 2). The third 10-year ISI period started October 15, 2005, and will end October 15, 2015. The licensee proposed alternatives to the American Society of Mechanical Engineers (ASME), Boiler and Pressure Vessel Code (Code), 1998 edition through the 2000 addenda, for the inspection and testing of snubbers.

The enclosed Safety Evaluation contains the Nuclear Regulatory Commission (NRC) staff's evaluation and conclusions. Based on the information provided in the relief request, the NRC staff has concluded that the licensee=s proposed alternative provides an acceptable level of quality and safety. Therefore, pursuant to Title 10 of the Code of Federal Regulations (10 CFR),

Part 50, Section 50.55a(a)(3)(i), the NRC staff authorizes the proposed alternative for the third 10-year ISI and IST interval for Catawba Unit 2.

Sincerely,

/RA/

Evangelos C. Marinos, Chief Plant Licensing Branch II-1 Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-414

Enclosure:

Safety Evaluation cc w/encl: See next page

October 31, 2007 Mr. J. R. Morris Site Vice President Catawba Nuclear Station Duke Power Company LLC 4800 Concord Road York, SC 29745

SUBJECT:

CATAWBA NUCLEAR STATION, UNIT 2, RELIEF 07-CN-003 FOR SNUBBER VISUAL EXAMINATION AND FUNCTIONAL TESTING RELATED TO THE THIRD 10-YEAR INTERVAL INSERVICE INSPECTION AND INSERVICE TESTING PROGRAMS (TAC NO. MD4657)

Dear Mr. Morris:

By letter dated February 26, 2007, Duke Power Company LLC (the licensee), submitted Relief Request No. 07BCN-003, for its third 10-year interval inservice inspection (ISI) and inservice testing (IST) programs for snubbers at Catawba Nuclear Station, Unit 2 (Catawba Unit 2). The third 10-year ISI period started October 15, 2005, and will end October 15, 2015. The licensee proposed alternatives to the American Society of Mechanical Engineers (ASME), Boiler and Pressure Vessel Code (Code), 1998 edition through the 2000 addenda, for the inspection and testing of snubbers.

The enclosed Safety Evaluation contains the Nuclear Regulatory Commission (NRC) staff's evaluation and conclusions. Based on the information provided in the relief request, the NRC staff has concluded that the licensee=s proposed alternative provides an acceptable level of quality and safety. Therefore, pursuant to Title 10 of the Code of Federal Regulations (10 CFR),

Part 50, Section 50.55a(a)(3)(i), the NRC staff authorizes the proposed alternative for the third 10-year ISI and IST interval for Catawba Unit 2.

Sincerely,

/RA/

Evangelos C. Marinos, Chief Plant Licensing Branch II-1 Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-414

Enclosure:

Safety Evaluation cc w/encl: See next page DISTRIBUTION:

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ADAMS Accession No: ML072820108 *SE input dated NRR-028 OFFICE LPL2-1/PM LPL2-1/LA NRR/CPTB/BC OGC NLO LPL2-1/BC NAME JStang MO=Brien JMcHale* MBaty EMarinos DATE 10/22/07 10/ 22/07 05/24/2007 10/23/07 10/31/07 OFFICIAL AGENCY RECORD

Catawba Nuclear Station, Units 1 & 2 Page 1 of 2 cc:

Site Vice President Assistant Director Catawba Nulcear Station Division of Waste Management Duke Power Company, LLC Bureau of Land and Waste Management 4800 Concord Road Dept. of Health and Environmental Control York, SC 29745 2600 Bull Street Columbia, South Carolina 29201-1708 Associate General Counsel and Managing Attorney Manager Duke Energy Carolinas, LLC Nuclear Regulatory Issues 526 South Church Street - EC07H and Industry Affairs Charlotte, North Carolina 28202 Duke Energy Corporation 526 South Church Street Regulatory Compliance Mail Stop EC05P Duke Energy Corporation Charlotte, North Carolina 28202 4800 Concord Road York, South Carolina 29745 Saluda River Electric P.O. Box 929 North Carolina Municipal Power Laurens, South Carolina 29360 Agency Number 1 1427 Meadowwood Boulevard Vice President P.O. Box 29513 Customer Relations and Sales Raleigh, North Carolina 27626 Westinghouse Electric Company 6000 Fairview Road County Manager of York County 12th Floor York County Courthouse Charlotte, North Carolina 28210 York, South Carolina 29745 Owners Group (NCEMC)

Piedmont Municipal Power Agency Duke Energy Corporation 121 Village Drive 4800 Concord Road Greer, South Carolina 29651 York, South Carolina 29745 Assistant Attorney General Senior Counsel North Carolina Department of Justice Duke Energy Carolinas, LLC P.O. Box 629 526 South Church Street - EC07H Raleigh, North Carolina 27602 Charlotte, NC 28202 NCEM REP Program Manager Division of Radiation Protection 4713 Mail Service Center NC Dept. of Environment, Health, Raleigh, North Carolina 27699-4713 and Natural Resources 3825 Barrett Drive North Carolina Electric Membership Corp. Raleigh, North Carolina 27609-7721 P.O. Box 27306 Raleigh, North Carolina 27611 Group Vice President, Nuclear Generation and Chief Nuclear Officer Senior Resident Inspector P.O. Box 1006-EC07H U.S. Nuclear Regulatory Commission Charlotte, NC 28201-1006 4830 Concord Road York, South Carolina 29745

Catawba Nuclear Station, Units 1 & 2 Page 2 of 2 cc:

Division of Radiation Protection NC Dept. of Environment, Health, and Natural Resources 3825 Barrett Drive Raleigh, North Carolina 27609-7721 Group Vice President, Nuclear Generation and Chief Nuclear Officer P.O. Box 1006-EC07H Charlotte, NC 28201-1006

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REQUEST FOR RELIEF NO. 07-CN-003 CATAWBA NUCLEAR STATION, UNIT 2 DUKE POWER COMPANY LLC DOCKET NO. 50-414

1.0 INTRODUCTION

By letter dated February 26, 2007, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML070650417) Duke Power Company LLC (the licensee), submitted Relief Request 07-CN-003 for its third 10-year interval inservice inspection (ISI) and inservice testing (IST) programs for snubbers at Catawba Nuclear Station, Unit 2 (Catawba Unit 2). The licensee requested relief from certain ISI and examination requirements of the American Society of Mechanical Engineers, Boiler and Pressure Vessel Code (ASME Code),Section XI, 1998 edition through 2000 addenda, Article IWF-5000. IWF-5000 references ASME/ANSI (American National Standards Institute) OM, Part 4 (OM-4), 1987 edition with OMa-1988 addenda. The licensee proposed to perform the above snubber surveillance activities using the Updated Final Safety Analysis Report (UFSAR), Chapter 16, Selected Licensee Commitment (SLC) 16.9-13, ASnubbers.@ This relief request is for the third 10-year ISI and IST programs for Catawba Unit 2.

2.0 REGULATORY EVALUATION

The ISI and IST of ASME Code Class 1, 2, and 3 components shall be performed in accordance with Section XI, ARules 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), Part 50, Section 50.55a(g), except where specific written relief has been granted by the Commission, pursuant to 10 CFR 50.55a(f)(6)(i) IST and 10 CFR 50.55a(g)(6)(i) ISI. Section 50.55a(a)(3) states that alternatives to the requirements of the 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 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), twelve months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein. The applicable edition of Section XI of

the ASME Code for the Catawba Unit 2 third 10-year ISI interval is the 1998 edition up to and including the 2000 addenda.

3.0 TECHNICAL EVALUATION

3.1 Relief Request 07-CN-003 3.1.1 Component for Which Relief is Requested All Catawba Unit 2 safety-related ASME Code Class 1, 2 and 3 snubbers.

3.1.2 Code Requirements The ASME Code,Section XI, Article IWF-5000, provides inservice inspection requirements for snubbers.

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 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 Catawba Unit 2 SLC 16.9-13, ASnubbers,@ 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 ASME Section XI, 1998 edition through 2000 addenda, IWF-5300(a) and (b) specifies that snubber inservice examinations and tests be performed in accordance with the OM-4.

IWF-5300(c) requires examinations of integral and non-integral attachments to snubbers, including lugs, bolting, pins, and clamps.

Snubber examinations and tests are currently performed under the UFSAR, Chapter 16, Selected Licensee Commitment (SLC) 16.9-13, ASnubbers.@ The licensee indicated that the proposed inspection program as defined by this SLC provides for an acceptable level of quality and safety equal to or greater than that of the proposed OM-4.

The SLC lists visual examination requirements for snubbers that are compatible with ASME Section XI VT-3 requirements. The SLC also incorporates the reduced visual examination frequency table as provided in NRC Generic Letter (GL) 90-09. SLC use results in a significant reduction in unnecessary radiological exposure to plant personnel, a savings in company

resources, and compliance with visual examination requirements while maintaining the same confidence level in snubber operability as that provided by following the ASME Section XI requirements.

Failure Mode Grouping 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 SLC program all snubbers in the population would be placed in a shortened inspection interval. On this basis the existing 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. The SLC program at Catawba requires supplemental testing for all failures until the desired confidence level is assured, with no allowance to reclassify failed snubbers.

Visual Examinations IWF-5000 requires that examinations be performed using the VT-3 visual examination method described in IWA-2213. IWA-2213 reads as follows:

AVT-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 bolted or 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 supports.@

The Catawba SLC states that:

AVisual inspections shall verify that: (1) the snubber has no visible indications of damage or impaired operability, (2) attachments to the foundation or supporting structure are functional, and (3) fasteners for the attachment of the snubber to the component and to the snubber anchorage are functional.@

Catawba Procedure MP/0/A/7650/085, AVisual Inspection of Snubbers,@ is used to implement the SLC inspections and includes requirements that the following items be checked: loose or missing locking devices, missing spacers, paint or corrosion issues, connecting devices, visible damage, welds, loose jam nuts on extensions, leakage, orientation, fluid level.

The SLC makes no distinction between integral and non-integral attachments. All are included in the examination to verify overall structural integrity. The request is not intended to exclude attachments from examination requirements, but only to use the SLC as the governing document for all examinations. With the SLC and Code requirements being comparable, it is preferable to utilize the SLC in order to maintain consistent programmatic and procedural control between Unit 1 and Unit 2.

3.1.5 Nuclear Regulatory Commission (NRC) Staff's Evaluation of Relief Request 07-CN-003 The licensee requested relief from the requirements of ASME Code,Section XI, paragraphs IWF-5300(a), (b), and (c). 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 Catawba Unit 1 SLC 16.9-13 in lieu of meeting the requirements in ASME Code,Section XI, paragraphs IWF-5300(a), (b) and (c).

ASME Code,Section XI, paragraph IWF-5300(a) requires that inservice visual inspections be performed in accordance with ASME/ANSI OM-4, using the VT-3 visual examination method described in paragraph IWA-2213.

Paragraph, IWF-5300(b) requires that inservice tests be performed in accordance with ASME/ANSI OM-4.

Paragraph, IWF-5300(c) requires that integral and non-integral attachments for snubbers, including lugs, bolting, pins, and clamps, be examined in accordance with Subsection IWF.

ASME Code,Section XI, Table IWA-1600-1 states that ASME/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 the SLC 16.9-13 and its bases for inservice visual examination and functional testing of all safety-related snubbers including lugs, bolting, pins, and clamps. 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.

SLC 16.9-13 incorporates Generic Letter (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.

The licensee states that the SLC makes no distinction between integral and non-integral attachments. All are included in the examination to verify overall structural integrity. The request is not intended to exclude attachments from examination requirements, but only to use the SLC as the governing document for all examinations.

The licensee is not requesting relief from Subarticle IWF-5200, APreservice Examination and Tests,@ or IWF-5400, ARepair/Replacement Activities,@ of Article IWF-5000, and will continue to use appropriate station procedures and processes to meet these Code requirements.

Catawba Unit 2 SLC 16.9-13 defines inservice examination requirements, method of examination, subsequent examination intervals, failure evaluation, inservice operability test

requirements, initial snubber sample size, additional sampling, failure evaluation, test failure mode groups, and corrective actions for the 10% sample and 37 sample plans that are similar to those provided by OM-4. OM-4 requirements and SLC 16.9-13 criteria are compared and summarized in the following table:

Criteria ASME/ANSI OM-4 -1987 through Catawba Unit 2 OMa-1988 addenda SLC 16.9-13 Requirements Inservice Examination

1. Visual Paragraph 2.3.1.1, Visual SLC 16.9-13, requires that visual Examination Examination, states that snubber inspections shall verify that (1) the visual examinations shall identify snubber has no visible indications impaired functional ability due to of damage or impaired operability; physical damage, leakage, (2) attachments to the foundation corrosion, or degradation. or supporting structure are functional; and (3) Fasteners for the attachment of the snubber to the component and to the snubber anchorage are functional.

2. Visual Paragraph 2.3.2.2 provides Table 16.9-13-1 provides snubber Examination examination interval frequency. visual inspection interval frequency.

Interval Frequency

3. Method of IWF-5300(a) requires use of the The licensee states that Procedure Visual VT-3 visual examination method MP/0/A/7650/085, AVisual Examination described in IWA-2213. Inspection of Snubbers,@ is used to implement the SLC inspection requirements. The SLC visual inspection requirements are comparable with ASME Code,Section XI, VT-3 requirements.

4. Subsequent Paragraph 2.3.2 provides Table 16.9-13-1 provides a Examination guidance for inservice snubber visual inspection interval Intervals examination intervals based on based on the number of the number of unacceptable unacceptable snubbers snubbers discovered. discovered. These requirements are similar to NRC GL 90-09.

5. Inservice Paragraph 2.3.4.1 states that SLC 16.9-13, states that snubbers Examination snubbers not meeting which appear inoperable as a Failure examination and acceptance result of visual inspections shall be Evaluation criteria shall be evaluated to classified as unacceptable and determine the cause of may be reclassified acceptable for unacceptability. the purpose of establishing the

Criteria ASME/ANSI OM-4 -1987 through Catawba Unit 2 OMa-1988 addenda SLC 16.9-13 Requirements next visual inspection interval, provided that (i) the cause of the rejection is clearly established and remedied for that particular snubber and for other snubbers irrespective of type that may be generically susceptible, and (ii) the affected snubber is functionally tested in the as-found condition and determined operable per acceptance criteria of the SLC.

Inservice Operability Test

1. Inservice Paragraph 3.2.1.1, Operability SLC 16.9-13, states that snubbers Operability Test, states that snubber shall be functionally tested either Test operational readiness tests shall in-place or in a bench test.

Requirements verify activation, release rate, and Functional test acceptance criteria breakaway force or drag force by requires a functional test to verify either an in-place or bench test. activation in tension and compression, force required to initiate or maintain motion within the specified range in both directions of travel for mechanical snubbers, and snubber bleed or release rate where required.

2. Snubber Paragraph 3.2.3 states that each SLC 16.9-13, functional testing Sample size defined test plan group shall use specifies sample testing plans.

either a 10% sampling plan; a A37 The licensee states that Catawba testing sample plan;@ or a A55 utilizes four groupings for snubbers testing sample plan@ during each testing. Separate 10% sample refueling outage. plans for (1) small bore Lisega hydraulic snubbers; (2)

Anchor/Darling mechanical snubbers, and (3) large bore steam generator snubbers, and a 37 sample plan for PSA mechanical snubbers. The 10% testing sample and 37 testing sample plans are similar to the plans as specified in the OM-4.

3. Additional (a) 10% Testing Sample Plan: (a) 10% Testing Sample Plan:

Sampling Paragraph 3.2.3.1(b) states that SLC 16.9-13, Bases under for any snubber(s) determined to functional testing requires an

Criteria ASME/ANSI OM-4 -1987 through Catawba Unit 2 OMa-1988 addenda SLC 16.9-13 Requirements be unacceptable as a result of additional 10% of all snubbers shall testing, an additional sample of at be tested until no more failures are least one-half the size of the initial found or until all snubbers have sample lot shall be tested. been functionally tested.

(b) 37 Testing Sample Plan: (b) 37 Testing Sample Plan:

Paragraph 3.2.3.2(b) states that The licensee states that SLC for any snubber(s) determined to 16.9-13 requirements are same as be unacceptable as a result of of the OM-4 Code. (Detailed testing, an additional random evaluation is provided above, in sample of at least one-half the Item 3 Additional Sampling) size of the initial sample lot shall be tested.

4. Inservice Paragraph 3.2.4.1 states that SLC 16.9-13, Bases under Operability snubbers not meeting the AFunctional Test Failure Analysis,@

Failure operability testing acceptance states that an engineering Evaluation criteria in paragraph 3.2.1 shall be evaluation shall be made of each evaluated to determine the cause failure to meet the functional test of the failure. acceptance criteria to determine the cause of the failure. If any snubber selected for functional testing either fails to lock up or fails to move, i.e., frozen in place, the cause of failure will be evaluated. If the failure is caused by the manufacturer or design deficiency, all snubbers of the same type subject to the same defect shall be functionally tested.

5. Test Failure Paragraph 3.2.4.2 states that SLC 16.9-13, Bases under Mode Groups unacceptable snubber(s) shall be AFunctional Test Failure Analysis,@

categorized into failure mode states that all snubbers that fail to group(s). A test failure mode meet the functional criteria must be group(s) shall include all evaluated to determine the cause, unacceptable snubbers that have and potential for applicability of the a given failure mode, and all other failure mode to other snubbers.

snubbers subject to the same Further the licensee states that all failure mode. snubbers susceptible to the same failure conditions would be identified and evaluated, or replaced without categorizing a mode group(s).

6. Corrective Paragraphs 3.2.5.1 and 3.2.5.2 SLC 16.9-13 states that snubbers Actions for state that unacceptable snubbers which fail the visual inspection or 10% Testing shall be repaired, modified, or the functional test acceptance

Criteria ASME/ANSI OM-4 -1987 through Catawba Unit 2 OMa-1988 addenda SLC 16.9-13 Requirements Sample Plan replaced. criteria shall be repaired or or replaced. Replacement snubbers 37 Testing which have repairs which might Sample Plan affect functional test results shall be tested to meet the functional test criteria before installation. The licensee states that the SLC makes no allowance for isolated failures.

The unacceptable snubbers would be repaired or replaced.

3.1.5.1 Inservice Examination Requirements (1) Visual Examination SLC 16.9-13, requires that visual inspections shall verify that (1) the snubber has no visible indications of damage or impaired operability, (2) attachments to the foundation or supporting structure are functional, and (3) fasteners for the attachment of the snubber to the component and to the snubber anchorage are functional. The visual examination per SLC 16.9-13 verifies visible indication of damage or impaired operability of snubbers as well as its attachments and supports. OM-4, paragraph 2.3.1.1, requires snubber visual examinations to identify impaired functional ability due to physical damage, leakage, corrosion, or degradation. Therefore, SLC 16.9-13 snubber visual examination requirements are considered to be equivalent to snubber visual examination requirements of OM-4 paragraph 2.3.1.1.

(2) Visual Examination Interval Frequency SLC Table 16.9-13-1 provides snubber visual inspection interval frequency requirements which are different than the OM-4 visual inspection interval requirements. Table 16.9-13-1 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-5300(a) requires that inservice examination be performed in accordance with ASME/ANSI 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.

The Catawba Units 1 and 2 SLC states that: AVisual inspections shall verify that (1) the snubber has no visible indications of damage or impaired operability, (2) attachments to the foundation or supporting structure are functional, and (3) fasteners for the attachment of the snubber to the component and to the snubber anchorage are functional.@

The licensee states that ACatawba Procedure MP/0/A/7650/085, 'Visual Inspection of Snubbers,'

is used to implement the SLC inspections and includes requirements that the following items be checked: loose or missing locking devices, missing spacers, paint or corrosion issues, connecting devices, visible damage, welds, loose jam nuts on extensions, leakage, orientation, fluid level.@

The licensee makes the argument that the intent and scope of IWA-2213 and SLC are essentially equals, although the Code wording is more detailed than the SLC in listing specific items to be included. However, these items are intuitive to meeting the SLC requirements and are more specifically addressed in the implementing procedure, which closely parallels the Code list. SLC examinations are performed using task qualified personnel who are specifically trained for the SLC examinations and who are familiar with snubber and component support operation and maintenance. Also the SLC makes no distinction between integral and non-integral attachments. All are included in the examination to verify overall structural integrity.

Therefore, the intent and scope of OM-4, VT-3 examination requirements are equivalent to the licensees SLC visual inspection requirements. Therefore, the NRC staff finds the licensee=s method of snubber visual inspection provides an acceptable level of quality and safety and is acceptable.

(4) Subsequent Examination Intervals SLC Table 16.9-13-1 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 SLC Table 16.9-13-1 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. SLC 16.9-13, 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 (i) the cause of the rejection is clearly established and remedied for that particular snubber and for other snubbers irrespective of type that may be generically susceptible, and (ii) the affected snubber is functionally tested in the

as-found condition and determined operable per acceptance criteria of the SLC. The licensee's program is considered to be equivalent to the requirements of OM-4. Therefore, the NRC staff finds that the SLC=s inservice examination failure evaluation requirements provide an acceptable level of quality and safety.

3.1.5.2 Inservice Operability Testing (1) Inservice Operability Test Requirements SLC 16.9-13, states that snubbers shall be functionally tested either in-place or in a bench test.

SLC functional test acceptance criteria requires a functional test to verify (i) activation in tension and compression, (2) snubber bleed or release rate where required for mechanical snubbers, (3) the force required to initiate or maintain motion is within the specified range in both direction of travel, and (4) 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 SLC requirements are considered to be equivalent to the snubber operability test requirements of OM-4 paragraph 3.2.1. Therefore, the SLC functional test requirements provide an acceptable level of quality and safety.

(2) Snubber Sample Size SLC 16.9-13, Functional testing states that at least 10% of all snubbers shall be functionally tested either in-place or in a bench test. These tests are normally performed during refueling outages. OM-4, Section 3.2.3 requires either a 10% testing sampling plan, a A37 testing sample plan,@ or a A55 testing sample plan.@ The licensee states that they are using four groupings for snubbers testing. Separate 10% sample plans are used for small bore Lisega hydraulic snubbers, Anchor/Darling mechanical snubbers, and large bore SG snubbers, and a 37 sample plan is used for Pacific Scientific America (PSA) mechanical snubbers. The 10 percent testing sample and 37 testing sample plans are similar to the plans as specified in the OM-4. As a result, the number of snubbers tested during outages are considered to be equivalent to the OM-4 requirements. Therefore, the SLC requirements of snubber sample size provide an acceptable level of quality and safety.

(3) Additional Sampling (a) For 10% snubbers sample plan SLC 16.9-13 states that for each snubber of a type that does not meet the functional test acceptance criteria, an additional 10% of all snubbers shall be functionally tested until no more failures are found or until all snubbers have been functionally 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% sample program, an additional 5% of the same type of snubber in the overall population would need to be tested.

Therefore, SLC 16.9-13 requirements for additional sampling for a 10% sample plan are considered to be acceptable.

(b) For 37 snubbers 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 the total number of snubbers found to be unacceptable. For a 37 sample plan, this is represented as equation N = 37(1 + C/2) in Appendix C of the OM-4 Code.

The SLC requirement is the same as it requires a representative random sample of each test group to satisfy the equation C = 0.055N - 2.007, where N = the number tested, and C = the number of unacceptable snubbers. For the initial sample (C =0), this equation gives N = 36.5 snubbers, rounding up to 37. Likewise, for each failure the additional snubbers test required will round up to 18, which matches the number required in the ASME Code equation. Therefore, SLC 16.9-13 requirements for additional sampling for the 37 sample plan are considered to be acceptable.

(4) Inservice Operability Failure Evaluation OM-4 paragraph 3.2.4.1 requires that snubbers not meeting operability testing acceptance criteria in paragraph 3.2.1 are to be evaluated to determine the cause of the failure. The cause of failure evaluation requires a review of the information related to other unacceptable snubbers and a determination whether other snubbers of similar design would require further examination.

SLC 16.9-13, under AFunctional Test Failure Analysis,@ 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. If any snubber selected for functional testing either fails to lock up or fails to move, i.e., frozen in place, the cause of failure will be evaluated. If the failure is caused by the manufacturer or design deficiency, all snubbers of the same type subject to the same defect shall be functionally tested. Therefore, the NRC staff finds that the SLC 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. SLC 16.9-13, under AFunctional Test Failure Analysis,@ states that all snubbers that fail to meet the functional criteria must be evaluated to determine the cause, and the potential for applicability of the failure mode to other snubbers. The licensee further states that all snubbers susceptible to the same failure conditions would be identified and evaluated, or replaced without categorizing a mode group(s).

Therefore, the SLC requirements are considered to be equivalent to the OM-4 requirements, and are acceptable.

(6) Inservice Operability Testing Corrective Actions for 10% Sample or 37 Sample Plan OM-4, paragraphs 3.2.5.1 and 3.2.5.2 require that unacceptable snubbers be adjusted, repaired, modified, or replaced. SLC 16.9-13 states that snubbers which fail the visual inspection or the functional test acceptance criteria shall be repaired or replaced. Replacement snubbers which have repairs which might affect functional test results shall be tested to meet the functional test criteria before installation. The licensee states that the SLC makes no allowance for isolated failures. The unacceptable snubbers would be repaired or replaced. Therefore, the NRC staff

finds that the SLC corrective actions associated with unacceptable snubbers at Catawba Unit 2 are considered to be equivalent to the OM-4 requirements.

Based on the above discussions, the NRC staff finds that snubber inservice visual examinations and functional testing, conducted in accordance with SLC 16.9-13, provide reasonable assurance of snubber operability and provide a level of quality and safety equivalent to that of ASME Code,Section XI, Subarticles IWF-5300(a), (b) and (c). Therefore, the NRC staff finds the licensee=s proposed alternative provides an acceptable level of quality and safety with respect to snubber inservice visual inspection and functional testing. It should be noted that in authorizing Relief Request 07-CN-003, SLC 16.9-13 becomes a regulatory requirement that may be used in lieu of ASME Code,Section XI requirements for performing inservice inspection and testing of snubbers. Changes to these requirements must be reviewed and approved by the NRC staff for authorization pursuant to 10 CFR 50.55a(a)(3) or as an exemption pursuant to 10 CFR 50.12.

4.0 CONCLUSION

Based on the information provided, the NRC staff concludes that the proposed alternative to use SLC 16.9.13 for snubber 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 Catawba Unit 2 third 10-year ISI and IST intervals.

All other requirements of ASME Code,Section XI which have not been specifically requested remain applicable, including third-party review by the Authorized Nuclear Inservice Inspector.

Principal Contributor: G. Bedi, NRR Date: October 31, 2007