ML062230421

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

ML062230421
Person / Time
Site:	Catawba
Issue date:	09/07/2006
From:	Marinos E NRC/NRR/ADRO/DORL/LPLII-1
To:	Jamil D Duke Power Co
Stang J, NRR/DORL, 415-1345
References
05-CN-002, TAC MC6942, TAC MD2811
Download: ML062230421 (17)

Text

September 7, 2006 Mr. Dhiaa Jamil Vice President Catawba Nuclear Station Duke Power Company LLC 4800 Concord Road York, SC 29745

SUBJECT:

CATAWBA NUCLEAR STATION, UNIT 1, REQUEST FOR RELIEF FOR SNUBBER VISUAL EXAMINATION AND FUNCTIONAL TESTING RELATED TO THE THIRD 10-YEAR INTERVAL INSERVICE INSPECTION PROGRAM (TAC NOS. MC6942 AND MD2811)

Dear Mr. Jamil:

By letter dated April 29, 2005, as supplemented by letter dated May 22, 2006, Duke Power Company LLC (the licensee), submitted Relief Request No. 05-CN-002, for its third 10-year interval inservice inspection (ISI) and inservice testing (IST) programs for snubbers at Catawba Nuclear Station, Unit 1 (Catawba Unit 1). The third 10-year ISI period started June 30, 2005, and will end June 30, 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 licensees 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 1.

Sincerely,

/RA/

Evangelos C. Marinos, Chief Plant Licensing Branch II-1 Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-413

Enclosure:

Safety Evaluation cc w/encl: See next page

Mr. Dhiaa Jamil September 7, 2006 Vice President Catawba Nuclear Station Duke Power Company LLC 4800 Concord Road York, SC 29745

SUBJECT:

CATAWBA NUCLEAR STATION, UNIT 1, REQUEST FOR RELIEF FOR SNUBBER VISUAL EXAMINATION AND FUNCTIONAL TESTING RELATED TO THE THIRD 10-YEAR INTERVAL INSERVICE INSPECTION PROGRAM (TAC NOS. MC6942 AND MD2811)

Dear Mr. Jamil:

By letter dated April 29, 2005, as supplemented by letter dated May 22, 2006, Duke Power Company LLC (the licensee), submitted Relief Request No. 05-CN-002, for its third 10-year interval inservice inspection (ISI) and inservice testing (IST) programs for snubbers at Catawba Nuclear Station, Unit 1 (Catawba Unit 1). The third 10-year ISI period started June 30, 2005, and will end June 30, 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 licensees 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 1.

Sincerely,

/RA/

Evangelos C. Marinos, Chief Plant Licensing Branch II-1 Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-413

Enclosure:

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

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S Lee, EDO RGN II TLiu, NRR ADAMS Accession No: ML062230421 *SE input dated NRR-028 OFFICE LPL2-1/PM LPL2-1/LA NRR/CPTB/ABC OGC LPL2-1/BC NAME JStang MOBrien TLiu* DRoth (nlo) EMarinos DATE 08/21/06 08/30/06 07/28/06 09/07/06 09/07/06 OFFICIAL AGENCY RECORD

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

Mr. Randy Hart, Manager North Carolina Electric Membership Corp.

Regulatory Compliance P.O. Box 27306 Duke Energy Corporation Raleigh, North Carolina 27611 4800 Concord Road York, South Carolina 29745 Senior Resident Inspector U.S. Nuclear Regulatory Commission Ms. Lisa F. Vaughn 4830 Concord Road Duke Energy Corporation York, South Carolina 29745 526 South Church Street P. O. Box 1006 Mr. Henry Porter, Assistant Director Mail Code = EC07H Division of Waste Management Charlotte, North Carolina 28201-1006 Bureau of Land and Waste Management Dept. of Health and Environmental Control North Carolina Municipal Power 2600 Bull Street Agency Number 1 Columbia, South Carolina 29201-1708 1427 Meadowwood Boulevard P.O. Box 29513 Mr. R.L. Gill, Jr., Manager Raleigh, North Carolina 27626 Nuclear Regulatory Issues and Industry Affairs County Manager of York County Duke Energy Corporation York County Courthouse 526 South Church Street York, South Carolina 29745 Mail Stop EC05P Charlotte, North Carolina 28202 Piedmont Municipal Power Agency 121 Village Drive Saluda River Electric Greer, South Carolina 29651 P.O. Box 929 Laurens, South Carolina 29360 Ms. Karen E. Long Assistant Attorney General Mr. Peter R. Harden, IV, Vice President North Carolina Department of Justice Customer Relations and Sales P.O. Box 629 Westinghouse Electric Company Raleigh, North Carolina 27602 6000 Fairview Road 12th Floor NCEM REP Program Manager Charlotte, North Carolina 28210 4713 Mail Service Center Raleigh, North Carolina 27699-4713 Mr. T. Richard Puryear Owners Group (NCEMC)

Duke Energy Corporation 4800 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 Mr. Henry Barron 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. 05-CN-002 CATAWBA NUCLEAR STATION, UNIT 1 DUKE POWER COMPANY LLC DOCKET NO. 50-413

1.0 INTRODUCTION

By letter dated April 29, 2005, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML051300359) Duke Power Company LLC (the licensee), submitted Relief Request 05-CN-002 for its third 10-year interval inservice inspection (ISI) and inservice testing (IST) programs for snubbers at Catawba Nuclear Station, Unit 1 (Catawba Unit 1). In response to the Nuclear Regulatory Commission (NRC) staffs request for additional information (RAI), the licensee submitted a letter dated May 22, 2006, (ADAMS Accession No. ML061520445).

The licensee requested relief from certain inservice inspection 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. 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, Snubbers. This relief request is for the third 10-year ISI and IST programs for Catawba Unit 1.

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, 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), 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 1 third 10-year ISI interval is the 1998 edition up to and including the 2000 addenda.

3.0 TECHNICAL EVALUATION

3.1 Relief Request 05-CN-002 3.1.1 Licensee Relief Request The licensee requested relief from the ASME Code,Section XI, Article IWF-5000, Subarticle IWF-5300(a), (b), and (c) requirements. ASME Section XI, IWF-5300(a) requires that snubber visual examinations be performed in accordance with OM-4, using the VT-3 visual examination method described in IWA-2213. ASME Section XI, IWF-5300(b) requires that snubber inservice tests be performed in accordance with OM-4. ASME Section XI, 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. Relief was requested for all Catawba Unit 1 safety-related ASME Section XI Code Class 1, 2, and 3 snubbers.

3.1.2 Licensees 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, Snubbers. 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 uses 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:

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 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:

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.

Catawba 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 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.

3.1.3 Licensees Proposed Alternative Inservice examination and testing of snubbers will be performed in accordance with SLC 16.9.13 in lieu of IWF-5300(a), (b), and (c).

3.1.4 NRC Staff's Evaluation of Relief Request 05-CN-002 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 Section XI, paragraph IWF-5300(a) requires that inservice visual inspections be performed in accordance with ASME/ANSI OM, Part 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, Part 4, 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, Part 4 (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, Alternative 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. GL90-09 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.

In a response to the NRC staffs RAI, the licensee states in its letter dated May 22, 2006, that Catawba Unit 1 is not requesting relief from Subarticle IWF-5200, Preservice Examination and Tests or IWF-5400, Repair/Replacement Activities of the Article IWF-5000, and will continue to use appropriate station procedures and processes to meet these Code requirements.

Catawba 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 Part 4 -1987 Catawba, Unit 1, through OMa-1988 addenda SLC 16.9-13 Requirements Inservice Examination

1. Visual Paragraph 2.3.1.1, Visual SLC 16.9-13, Bases requires that Examination Examination, states that snubber visual inspections shall verify that visual examinations shall identify (1) the snubber has no visible impaired functional ability due to indications of damage or impaired physical damage, leakage, operability; (2) attachments to the corrosion, or degradation. 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.

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

Frequency requirements.

3. Method of IWF-5300(a) requires use of the Catawba states that Catawba Visual VT-3 visual examination method Procedure MP/0/A/7650/085, Examination described in IWA-2213. Visual Inspection of Snubbers, is used to implement the SLC inspection 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.

Criteria ASME/ANSI OM Part 4 -1987 Catawba, Unit 1, through OMa-1988 addenda SLC 16.9-13 Requirements

5. Inservice Paragraph 2.3.4.1 states that SLC 16.9-13, Bases, states that Examination snubbers not meeting snubbers which appear inoperable Failure examination and acceptance as a result of visual inspections Evaluation criteria shall be evaluated to shall be classified as unacceptable determine the cause of and may be reclassified acceptable unacceptability. Paragraph for the purpose of establishing the 2.3.4.2 states that snubbers found next visual inspection interval, unacceptable, may be tested in provided that (I) the cause of the accordance with the requirements rejection is clearly established and of paragraph 3.2 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, Bases states that Operability Test, states that snubber snubbers shall be functionally Test operational readiness tests shall tested either in-place or in a bench Requirements verify activation, release rate, and test. Functional test acceptance breakaway force or drag force by criteria requires a functional test to either an in-place or bench test. verify 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.

Criteria ASME/ANSI OM Part 4 -1987 Catawba, Unit 1, through OMa-1988 addenda SLC 16.9-13 Requirements

2. Snubber Paragraph 3.2.3 states that each SLC 16.9-13, Bases, Functional Sample size defined test plan group shall use Testing specifies sample testing either a 10% sampling plan; a 37 plans. In a response to RAI, the testing sample plan; or a 55 licensee states that Catawba testing sample plan during each utilizes four groupings for snubbers refueling outage. testing. Separate 10% sample 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 be unacceptable as a result of additional 10% of all snubbers testing, an additional sample of at shall be tested until no more least one-half the size of the initial failures are found or until all sample lot shall be tested. snubbers have been functionally (b) 37 Testing Sample Plan: tested.

Paragraph 3.2.3.2(b) states that (b) 37 Testing Sample Plan:

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

Criteria ASME/ANSI OM Part 4 -1987 Catawba, Unit 1, through OMa-1988 addenda SLC 16.9-13 Requirements

4. Inservice Paragraph 3.2.4.1 states that SLC 16.9-13, Bases under Operability snubbers not meeting the Functional 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 Functional 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 states that unacceptable which fail the visual inspection or 10% Testing snubbers shall be repaired, the functional test acceptance Sample Plan modified, or 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. In a response to RAI, the licensee states that the SLC makes no allowance for isolated failures. The unacceptable snubbers would be repaired or replaced.

3.1.4.1 Inservice Examination Requirements (1) Visual Examination SLC 16.9-13, Bases 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 paragraphs 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 Generic Letter (GL) 90-09, Alternative 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, Part 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.

Catawba SLC states 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 licensee states that Catawba 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 Catawba SLC Visual inspection 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 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 SLCs inservice examination failure evaluation requirements provide an acceptable level of quality and safety.

4.1.4.2 Inservice Operability Testing (1) Inservice Operability Test Requirements SLC 16.9-13, Bases, 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 (1) 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, Bases, 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 37 testing sample plan, or a 55 testing sample plan. In a response to an RAI, the licensee states that currently Catawba is using four grouping for snubbers testing. Separate 10%

sample plans are used for small bore Lisega hydraulic snubbers, Anchor/Darling mechanical snubbers, and large bore steam generator snubbers, and a 37 sample plan is used for PSA mechanical snubbers. The 10% 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 defined 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 an 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 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 to review the information related to other unacceptable snubbers and determine whether other snubbers of similar design would require further examination.

SLC 16.9-13, Bases under Functional 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, Bases under Functional Test Failure Analysis states that all snubbers that fail to meet the functional criteria must be evaluated to determine the cause, and potential for applicability of the failure mode to other snubbers. Further the licensee states that all snubbers susceptible to the same failure conditions would be identified and evaluated, or replaced with out 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. In a response to RAI, 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 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, provides reasonable assurance of snubber operability and provides 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 licensees 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 05-CN-002, 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 licensees proposed alternative is authorized for the Catawba Unit 1 third 10-year ISI and IST intervals.

Principal Contributor: G. Bedi, NRR Date: September 7, 2006