ML073110002

Safety Evaluation of Relief Request No. SNBR-1 the Second 10-Year Inservice Inspection and Examination Program for Snubbers

ML073110002
Person / Time
Site:	Watts Bar
Issue date:	11/20/2007
From:	Boyce T NRC/NRR/ADRO/DORL/LPLII-2
To:	Campbell W Tennessee Valley Authority
Moroney B, NRR/DORL, 415-3974
References
TAC MD4450
Download: ML073110002 (24)

Text

November 20, 2007 Mr. William R. Campbell, Jr.

Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801

SUBJECT:

WATTS BAR NUCLEAR PLANT, UNIT 1 - SAFETY EVALUATION OF RELIEF REQUEST SNBR-1 FOR THE SECOND 10-YEAR INSERVICE INSPECTION AND EXAMINATION PROGRAM FOR SNUBBERS (TAC NO. MD4450)

Dear Mr. Campbell:

By letter dated February 7, 2007, supplemented by letter dated May 9, 2007, Tennessee Valley Authority (the licensee) submitted Relief Request SNBR-1 for Watts Bar Nuclear Plant (WBN),

Unit 1. Pursuant to Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Section 50.55a(a)(3)(i), Relief Request SNBR-1 requested relief from certain American Society of Mechanical Engineers Code requirements pertaining to the examination and testing requirements for snubbers during the second 10-year inservice inspection (ISI) interval at WBN, Unit 1.

The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the licensees request and concludes that the proposed alternative provides an acceptable level of quality and safety.

Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), relief is granted for the second 10-year ISI interval at WBN, Unit 1, which began on May 27, 2007 and ends on May 26, 2017.

Further details on the bases for the NRC staffs conclusions are contained in the enclosed safety evaluation. If you have any questions regarding this issue, please feel free to contact the WBN, Unit 1 Project Manager, Brendan Moroney, at (301) 415-3974.

Sincerely,

/RA/

Thomas H. Boyce, Chief Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-390

Enclosure:

Safety Evaluation cc w/enclosures: See next page

ML073110002 NRR-028 OFFICE LPL2-2/PM LPL2-2/PM LPL2-2/LA CPTB/BC OGC LPL2-2/BC NAME JBowen BMoroney RSola JMcHale BMizuno TBoyce DATE 11 / 15

/07 11 / 14 /07 11 / 14 /07 11 / 15 /07 11/ 20/07 11 / 20 /07

William R. Campbell, Jr.

Tennessee Valley Authority WATTS BAR NUCLEAR PLANT cc:

Mr. Gordon P. Arent New Generation Licensing Manager Tennessee Valley Authority 5A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Ashok S. Bhatnagar Senior Vice President Nuclear Generation Development and Construction Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. James R. Douet Vice President Nuclear Support Tennessee Valley Authority 3R Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. H. Rick Rogers Vice President Nuclear Engineering & Technical Services Tennessee Valley Authority 3R Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Michael D. Skaggs, Site Vice President Watts Bar Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Spring City, TN 37381 General Counsel Tennessee Valley Authority 6A West Tower 400 West Summit Hill Drive Knoxville, TN 37902 Mr. John C. Fornicola, Manager Nuclear Assurance Tennessee Valley Authority 3R Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Larry E. Nicholson, General Manager Performance Improvement Tennessee Valley Authority 4X Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801 Ms. Beth A. Wetzel, Manager Corporate Nuclear Licensing and Industry Affairs Tennessee Valley Authority 4X Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801 Mr. Masoud Bajestani, Vice President Watts Bar Unit 2 Watts Bar Nuclear Plant Tennessee Valley Authority P.O. Box 2000, EQB 1B Spring City, TN 37381 Mr. Michael K. Brandon, Manager Licensing and Industry Affairs Watts Bar Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Spring City, TN 37381 Mr. Michael J. Lorek, Plant Manager Watts Bar Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Spring City, TN 37381 Senior Resident Inspector Watts Bar Nuclear Plant U.S. Nuclear Regulatory Commission 1260 Nuclear Plant Road Spring City, TN 37381 County Executive 375 Church Street Suite 215 Dayton, TN 37321 County Mayor P. O. Box 156 Decatur, TN 37322 Mr. Lawrence E. Nanney, Director Division of Radiological Health Dept. of Environment & Conservation Third Floor, L and C Annex 401 Church Street Nashville, TN 37243-1532

Enclosure SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SECOND 10-YEAR INTERVAL INSERVICE EXAMINATION PROGRAM FOR SNUBBERS RELIEF REQUEST SNBR-1 TENNESSEE VALLEY AUTHORITY WATTS BAR NUCLEAR PLANT, UNIT 1 DOCKET NO. 50-390

1.0 INTRODUCTION

By letter dated February 7, 2007, Tennessee Valley Authority, the licensee, submitted Relief Request SNBR-1 for the second 10-year interval inservice inspection (ISI) and testing program for snubbers (pin to pin inclusive) at Watts Bar Nuclear Plant (WBN), Unit 1. In response to the staffs request for additional information (RAIs), the licensee submitted its response in a letter dated May 9, 2007. 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, 2001 Edition through 2003 Addenda, Article IWF-5000. 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 WBN, Unit 1 second 10-year ISI interval started on May 27, 2007 and is scheduled to be completed by May 26, 2017.

2.0 REGULATORY REQUIREMENTS 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 WBN, Unit 1 second 10-year ISI interval is the 2001 Edition through 2003 Addenda.

The NRCs findings with respect to granting or denying the ISI program relief request are given below:

3.0 TECHNICAL EVALUATION

3.1 Relief Request SNBR-1 3.1.1 Component for Which Relief is Requested All WBN, Unit 1 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.

ASME Code,Section XI, IWA-4530(b) requires preservice inspection and testing to be performed in accordance with IWF-5200 following repair/replacement of a snubber.

ASME Code,Section XI, 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.

ASME Code,Section XI, 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.

ASME Code,Section XI, IWF-5400, references IWF-5200 for snubber examination and test requirements following repair/replacement activities.

ASME Code,Section XI, IWA-6210(c), requires the preparation of preservice and inservice inspection summary reports for Class 1 and 2 snubbers.

ASME Code,Section XI, IWA-6230, requires the preparation of an inservice inspection summary report after each refueling outage.

ASME Code,Section XI, IWA-6240, requires the submittal of summary reports (snubbers) to the regulatory authority.

ASME Code,Section XI, IWA-2110, requires Authorized Nuclear Inservice Inspector (ANII) involvement for snubber examination and testing.

3.1.3 Licensees Proposed Alternative The licensee proposes to use WBN, Unit 1 Technical Requirements Manual (TRM) TR 3.7.3, 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 Licensees Basis for Requesting Relief (as stated)

WBN, Unit 1 is required to update to the 2001 Edition through 2003 Addenda of ASME Code,Section XI for WBNs second ten-year ISI inspection interval. ASME Code,Section XI Class 1, 2 and 3 snubbers are examined and tested in accordance with WBN TRM TR 3.7.3 which was prepared in accordance with the guidance given by NRC in Generic Letter (GL) 90-09. The scope for snubbers examined and tested in accordance with TR 3.7.3 is not limited by line size or other applicable code exemptions and includes a numerically greater population of snubbers than the Section XI program. Examination and testing of the snubbers in accordance with both ASME Code,Section XI and the plant TRM would result in a duplication of effort utilizing different standards and require the preparation of a separate program and associated procedures. This would result in additional cost and unnecessary radiological exposure. In addition, the personnel performing snubber visual examinations would also be required to be certified in accordance with the American Society of Nondestructive Testing (ASNT) SNT-TC-1A, Personnel Qualification and Certification in Nondestructive Testing, and ASME/ASNT-CP-189, which is an additional certification as compared to the task training qualification required to perform the TRM required examinations and testing of snubbers. The existing TRM program for examination and testing of snubbers was promulgated and accepted by NRC.

The implementation of OM-1987, Part 4, with OMa-1988 Addenda would require WBN to initiate a snubber examination and testing program which would increase the manpower and potentially the radiation exposure to implement, when compared to the existing TRM mandated snubber program, without a compensating increase in the level of quality and safety.

The WBN TRM, TR 3.7.3, requirements will be utilized for the examination and testing of snubbers for preservice, inservice, and repair/replacement activities. The procedures utilized for these examinations are: 1-TRI-0-5, Snubber Visual Inspection; 1-TRI-0-7, Snubber Functional Testing (Mechanical Snubbers); and 1-TRI-0-8, Snubber Functional Testing (Paul Monroe Snubbers). The snubber visual examinations include the pin-to-pin area inclusive of applicable snubbers.

Testing of repaired and replaced snubbers will be performed in accordance with TR 3.7.3, Note 2.

A comprehensive list of snubbers is maintained in Technical Instruction TI-203, Snubber Program. Other related procedures include: Maintenance Instruction (MI)-0.044, Removal and Reinstallation of Mechanical Snubbers, and MI-0.05 Fluid Sampling and Maintenance for Paul Monroe Snubbers.

Snubber examination and testing data will be maintained in accordance with the requirements of TR 3.7.3, procedure SPP-3.1, Corrective Action Program, and implementing procedures 1-TRI-0-5, 1-TRI-0-7, and 1-TRI-0-8.

The areas inclusive of the pins back to building structure and to the component/piping being supported will remain in the ASME Code,Section XI examination boundary and IWF-5200(c) and IWF-5300(c) will be met through ASME Code,Section XI preservice examination and/or scheduled inservice examinations, as applicable, for the second interval.

Subarticle IWF-5400 provides the requirements for repair and replacement of snubbers to be in accordance with OM-4. Specifically, OM-4, Sections 1.5.6, Snubber Maintenance or Repair, and 1.5.7, Snubber Modification and Replacement, require repaired and replaced snubbers to meet the visual examination requirements of paragraph 2.3.1.2 and the operability test requirements of paragraph 3.2.11. Section 1.5.6 also requires an evaluation of the maintenance or repair activity and Section 1.5.7 requires a suitability evaluation on the replacement/modified snubber. TR 3.7.3 (Note 2) requires replacement snubbers and snubbers which have repairs which might affect the functional test results to be tested to meet the functional test criteria prior to installation.

Procedure 1-TRI-0-5 provides visual examination criteria for installation of a snubber after repair or replacement. The ASME Code,Section XI repair/replacement program at WBN documents the suitability of repairs/replacements per IWA-4160.

ASME Code,Section XI VT-3 certification required by personnel performing snubber visual examinations is an additional certification as compared with the TRM program training qualifications. Personnel performing the TRM required visual examinations are process qualified to perform the examinations and testing required by the TRM and implemented by the referenced procedures. This training currently includes a visual test associated with face mask fit and specific training on the acceptance criteria associated with procedure 1-TRI-0-5. Additional visual acuity verification for personnel performing snubber visual examinations will include visual acuity requirements that meet ASME Code,Section XI. The training and documentation of personnel to the visual acceptance criteria, specified in the TRM implementing procedures, provides an acceptable level of quality and safety.

Because relief is sought from the ASME Code,Section XI snubber examination and test requirements, there will be no ASME Code,Section XI snubber examination and test activities to require ANII involvement. The WBN TRM snubber program does not require the use of an ANII for examination and test requirements. The ANII will not be involved in the TRM required visual examination or testing activities performed in lieu of the ASME Code requirements. A snubber program manager provides oversight of the TRM snubber program implementation for both visual examination and functional testing. This oversight includes both review and evaluation of visual examination and functional testing data to ensure TRM requirements are met. The snubber program manager provides an acceptable level of quality and safety without ANII involvement in those activities. ANII involvement in other repair and replacement snubber activities, as required by IWA-2110(g) and (h) and implemented by the WBN ASME Code,Section XI Repair and Replacement Program will be maintained.

Subarticle IWA-6230 and OM-4, Sections 2.3 and 3.3 provide requirements for ASME Code,Section XI inservice examination and test documentation for snubbers and a summary report of examinations and testing. Under the alternate requirements for snubbers, there will be no ASME Code,Section XI inservice examination and testing to document in a summary report. TR 3.7.3 is implemented by implementing procedures/instructions 1-TRI-0-5, 1-TRI-0-7, and 1-TRI-0-8.

These instructions, written and approved in accordance with the TVA Nuclear Quality Assurance (QA) Program, include data sheets for documenting the visual examination and functional test data and results, and provide for documentation of nonconforming results and evaluation of those results. The completed data sheets are QA records and are controlled and maintained in accordance with the WBN QA records program. These records are available onsite for review and inspection. The QA records documenting snubber visual examinations and functional tests provide an acceptable level of quality and safety when compared to the requirements of ASME Code,Section XI and OM-4.

Based on the justification provided, the WBN method of examination and testing of snubbers, in accordance with TR 3.7.3 will provide an acceptable level of quality and safety.

3.1.5 NRC Staff Evaluation of Relief Request SNBR-1 The licensee requested authorization of an alternative to 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 visual examinations and functional testing of ASME Code Class 1, 2 and 3 snubbers be performed in accordance with the requirements of WBN TRM TR 3.7.3 and its procedures 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 licensee states that areas outside the snubber pins back to the building structure and to the component/piping being supported will remain in the ASME Code,Section XI examination boundary.

The applicable edition of Section XI of the ASME Code for the WBN second 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) references 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 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, shall be examined in accordance with the requirements of Subsection IWF. The licensee states that the areas inclusive of the pins back to building structure and to the component/piping being supported will remain in the ASME Code,Section XI examination boundary and IWF-5200(c) and IWF-5300(c) will be met through ASME Code,Section XI preservice examination and/or scheduled inservice examinations, as applicable, for the second interval.

OM-4 specifies the requirements for visual examination (paragraph 2.3), and functional testing (paragraph 3.2) of snubbers. The licensee proposes to use WBN TRM TR 3.7.3 surveillance requirements for visual inspection 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.

WBN TRM TR 3.7.3 incorporates 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. 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 to implement the requirements of TRM TR 3.7.3, WBN is using following implementing procedures:

1-TRI-0-5, Snubber Visual Inspection (Hydraulic and Mechanical) 1-TRI-0-7, Snubber Functional Testing (Mechanical Snubbers) 1-TRI-0-8, Snubber Functional Testing (Paul Monroe Snubbers)

Quality Assurance (QA) examination records are maintained in accordance with these implementing procedures.

TRM TR 3.7.3 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 and 37 sample plans that are similar to those provided by OM-4.

OM-4 requirements and TRM TR 3.7.3 criteria are compared and summarized in the following table and followed by a detailed review:

Criteria ASME/ANSI OM Part 4 -1987 including 1988 Addenda WBN TRM TR 3.7.3 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 Technical Surveillance Requirements (TSR) 3.7.3.1 requires visually inspection of each snubber in accordance with the acceptance criteria in TRM Table 3.7.3-1. Table 3.7.3-1 requires that visual inspections shall verify that: (a) there are no indications of damage or impaired operability; (b) attachments to the foundation or supporting structure are functional; and (c) fasteners for attachment of the snubber to the component and to the snubber anchorage are functional.

2. Visual Examination Interval Frequency Paragraph 2.3.2.2 provides examination interval frequency.

TRM Table 3.7.3-2 provides snubber visual inspection interval frequency.

3. Method of Visual Examination IWF-5200(a) and IWF-5300(a) requires use of the VT-3 visual examination method described in IWA-2213.

The licensee states that TRM TR 3.7.3 requirements contained in procedure 1-TRI-0-5 provide the basis for an examination equivalent to the VT-3 visual examination. (Detailed evaluation is provided below in Item 3, Method of Visual Examination)

Criteria ASME/ANSI OM Part 4 -1987 including 1988 Addenda WBN TRM TR 3.7.3

4. Subsequent Examination Intervals Paragraph 2.3.2 provides guidance for inservice examination intervals based on the number of unacceptable snubbers discovered.

TRM Table 3.7.3-2 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 Section 2.3.4 states that snubbers not meeting examination and acceptance criteria shall be evaluated to determine the cause of unacceptability.

TRM Table 3.7.3-1, Item 2 states that snubbers which appear inoperable as result of visual inspections shall be classified as unacceptable.

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.

TRM TSR 3.7.3.3 requires performance of a functional test on a representative sample of snubbers in accordance with Table 3.7.3-4 to determine acceptance with criteria in Table 3.7.3-5. Table 3.7.3-4 states that snubbers shall be functionally tested either in-place or in a bench test. Table 3.7.3-5 states that the snubber functional test is to verify (1) activation is achieved within specified range of velocity or acceleration in tension and compression; (2) bleed rate, or release rate where required, is present in both tension and compression within the specified range (hydraulic snubbers); and (3) the force required to initiate or maintain motion is within the specified range in both directions of travel (mechanical snubbers).

Criteria ASME/ANSI OM Part 4 -1987 including 1988 Addenda WBN TRM TR 3.7.3

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.

For hydraulic snubbers, TRM Table 3.7.3-4, Sample Plan A, Item 1 states that at least 10 percent of the total hydraulic snubber population shall be functionally tested either in-place or in a bench test. For mechanical snubbers, TRM Table 3.7.4, Sample Plan B, Item 1 states that an initial representative sample of 37 mechanical snubbers shall be functionally tested in accordance with Figure 3.7.3-1.

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.

or (b) 37 Testing Sample Plan:

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.

(a) 10 percent Testing Sample Plan for Hydraulic Snubbers: TRM Table 3.7.3-4, Sample Plan A, Item 2 requires that for each hydraulic snubber of a type that does not meet the functional test acceptance criteria of Table 3.7.3-5, an additional 10 percent of hydraulic snubbers shall be functionally tested until no more failures are found or until all hydraulic snubbers have been functionally tested.

(b) 37 Testing Sample Plan for Mechanical Snubbers: TRM Table 3.7.3-4, Sample Plan B, Item 1 requires that for each mechanical snubber type which does not meet the functional acceptance criteria of Table 3.7.3-5, another sample of at least 19 snubbers shall be tested.

These requirements are the same as those of OM-4.

Criteria ASME/ANSI OM Part 4 -1987 including 1988 Addenda WBN TRM TR 3.7.3

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.

TRM Table 3.7.3-5, Note 2 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. Further, Table 3.7.3-5, Note 4 states that If any snubber selected for functional testing either fails to lock up or fails to move, i.e., is 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 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 a given failure mode, and all other snubbers subject to the same failure mode.

Table 3.7.3-5, Note 2 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 operability of other snubbers irrespective of the type which may be subject to the same failure mode.

6. Corrective Actions for 10 percent Testing Sample Plan or 37 Testing Sample Plan Paragraph 3.2.5.1 states that unacceptable snubbers shall be repaired, modified, or replaced.

TR 3.7.3, Note 2 states that snubbers which fail the visual inspection or the functional test acceptance criteria shall be repaired or replaced.

Replacement snubbers and snubbers which have repairs which might affect the functional test results shall be tested to meet the functional test criteria before installation.

Inservice Examination Requirements (1)

Visual Examination TRM TSR 3.7.3.1 requires visual inspection of each snubber in accordance with the acceptance criteria in Table 3.7.3-1. Table 3.7.3-1 requires that visual inspections shall verify that: (a) there are no indications of damage or impaired operability; (b) attachments to the foundation or supporting structure are functional; and (c) fasteners for attachment of the snubber to the component and to the snubber anchorage are functional. The visual examination per TSR 3.7.3.1 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, TRM TR 3.7.3 snubber visual examination requirements are considered to be equivalent to snubber visual examination requirements of OM-4 paragraph 2.3.1.1 and are acceptable, and provide an acceptable level of quality and safety.

(2)

Visual Examination Interval Frequency TRM Table 3.7.3-2 provides snubber visual inspection interval frequency requirements which are different than the OM-4 visual inspection interval requirements. Table 3.7.3-2 incorporates the visual inspection interval frequency as specified in 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-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. The licensee states that personnel performing the TRM required visual examinations are process qualified to perform the examinations and testing required by the TRM and implemented by the referenced procedures. The licensee further states that WBN procedure 1-TRI-0-5 is used for visual examination. Section 4.5 of 1-TRI-0-5 states that prior to performing visual inspections, personnel shall meet the visual acuity requirements of IEP-301, NDE/QC Personnel Eye Examination Procedure, except that documentation discussed in IEP-301 shall be submitted to the Snubber Program Engineer to ensure only qualified personnel perform inspections.

Section 5.0, Acceptance Criteria, and Section 6.0, Performance, provide acceptance criteria equivalent to IWA-2213(a). The IWA-2213(a) VT-3 examination is conducted to determine the general mechanical and structural condition of components and their supports by verifying parameters such as clearances, settings, and physical displacements; to detect discontinuities and imperfections such as loss of integrity at bolted or welded connections, loose or missing parts, debris, corrosion, wear, or erosion; and to detect conditions that could affect operability or functional adequacy of snubbers and constant load and spring-type supports. The examination conducted in accordance with procedure 1-TRI-0-5 is a multi-step process to determine the acceptance of structural integrity, fasteners, alignment, and visual operability. Steps 6 through 14 of Section 6.0 of procedure 1-TRI-0-5 which implements TRM TR 3.7.3 encompass the snubber examination criteria provided in ASME Code,Section XI, IWA-2213. The licensee states that the level of examination detail and the visual acuity standards to satisfy the TRM TR 3.7.3 requirements contained in procedure 1-TRI-0-5 provide the basis for an examination equivalent to the VT-3 visual examination method specified in ASME Code,Section XI. 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 3.7.3-2 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 TR 3.7.3 provide an acceptable level of quality and safety and are 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. OM-4, paragraph 2.3.4.2 states that snubbers found unacceptable may be tested in accordance with the requirements of paragraph 3.2. TRM Table 3.7.3-1, Item 2 states that snubbers which appear inoperable as 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 (a) 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 (b) the affected snubber is functionally tested in as-found condition and determined operable per acceptance criteria of the Table 3.7.3-5. The licensee program is considered to be equivalent to the requirements of OM-4. Therefore, the NRC staff finds that the TRMs inservice examination failure evaluation requirements provide an acceptable level of quality and safety.

Inservice Operability Test Requirements (1)

Operability Test TRM TSR 3.7.3.3 requires performance of a functional test on a representative sample of snubbers in accordance with Table 3.7.3-4 to determine acceptance with criteria in Table 3.7.3-5.

Table 3.7.3-4 states that snubbers shall be functionally tested either in-place or in a bench test.

Table 3.7.3-5 states that the snubber functional test is to verify (1) activation is achieved within specified range of velocity or acceleration in tension and compression; (2) bleed rate, or release rate where required, is present in both tension and compression within the specified range (hydraulic snubbers); and (3) the force required to initiate or maintain motion is within the specified range in both directions of travel (mechanical snubbers). OM-4, paragraph 3.2.1.1, 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 operability test requirements provide an acceptable level of quality and safety.

(2)

Snubber Sample Size For hydraulic snubbers, TRM Table 3.7.3-4, Sample Plan A, Item 1 states that at least 10 percent of the total hydraulic snubber population shall be functionally tested either in-place or in a bench test. For mechanical snubbers, TRM Table 3.7.3-4, Sample Plan B, Item 1 states that an initial representative sample of 37 mechanical snubbers shall be functionally tested in accordance with Figure 3.7.3-1. OM-4, Section 3.2.3 requires either a 10 percent testing sampling plan, a 37 testing sample plan, or a 55 testing sample plan. The TRM is using a 10 percent sample plan criteria for hydraulic snubbers and 37 snubber plan criteria for mechanical snubbers which is equivalent to the requirements of OM-4. As a result, the number of snubbers tested during outages are considered to be equivalent to the OM-4 requirements. Therefore, the TRM snubber sample size provides an acceptable level of quality and safety.

(3)

Additional Sampling (a) 10 percent Testing Sample Plan for Hydraulic Snubbers OM-4, paragraph 3.2.3.1(b) states that the additional sample size must be at least one-half the size of the initial sample size lot 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.

TRM Table 3.7.3-4, Sample Plan A, Item 2 requires that for each hydraulic snubber of a type that does not meet the functional test acceptance criteria of the Table 3.7.3-5, an additional 10 percent of hydraulic snubbers shall be functionally tested until no more failures are found or until all hydraulic snubbers have been functionally tested. TRM requirements for 10 percent additional sampling for 10 percent Testing Sample Plan are more restrictive than the 5 percent additional sampling requirements of the OM-4 Code.

(b) 37 Testing Sample Plan for Mechanical Snubbers 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. TRM Table 3.7.3-4, Sample Plan B, Item 1 requires that for each mechanical snubber type which does not meet the functional acceptance criteria of Table 3.7.3-5, another sample of at least 19 snubbers shall be tested. TRM requirements are the same as those of the OM-4 Code.

Therefore, the TRM requirements of additional sampling are considered acceptable, and provide an acceptable level of quality and safety.

(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 be evaluated to determine the cause of the failure. The cause of failure evaluation requires the review of other unacceptable snubbers and determination of whether other snubbers of similar design would require further examination. TRM Table 3.7.3-5, Note 2 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. Further, Table 3.7.3-5, Note 4 states that if any snubber selected for functional testing either fails to lock-up or fails to move, i.e., is frozen in place, the cause of failure will be evaluated. If the failure is caused by a 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 TRM requirements related to inservice operability failure evaluation are considered to be equivalent to the OM-4 requirements, and are acceptable.

(5)

Test Failure Mode Groups OM-4 paragraph 3.2.4.2 requires that unacceptable snubbers be categorized into failure mode groups. 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. TRM Table 3.7.3-5, Note 2 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 operability of other snubbers irrespective of the type which may be subject to the same failure mode. The TRM does not specifically address Failure Mode Groups, however, the surveillance requirements of the TRM accomplish grouping criteria similar to the Code required Failure Mode Grouping.

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

(6)

Inservice Operability Testing Corrective Actions (for 10% testing sample plan or 37 snubber plan)

OM-4, paragraph 3.2.5.1 requires that unacceptable snubbers be adjusted, repaired, modified, or replaced. TRM TSR Note 2 states that snubbers which fail the visual inspection or the functional test acceptance criteria shall be repaired or replaced. Replacement snubbers and snubbers which have repairs which might affect the functional test results shall be tested to meet the functional test criteria before installation. Therefore, the NRC staff finds that the TRM corrective actions associated with unacceptable snubbers at WBN are considered to be equivalent to the OM-4 requirements.

Authorized Inspection Agency ASME Code,Section XI, IWA-2110 specifies various inspector duties related to examination and testing activities. IWA-9000 states that an Authorized Nuclear Inservice Inspector (ANIl) is a person who is employed and has been qualified by an Authorized Inspection Agency (AIA) to verify examination, tests and repair/replacement activities. The licensee states that WBNs snubber inspection and testing in accordance with the TRM TR 3.7.3 does not include involvement of an AIA or ANIIs in the second 10-year inspection interval. However, ANII involvement in other repair and replacement snubber activities, as required by IWA-2110(g) and (h) and implemented by the WBN ASME Code,Section XI Repair and Replacement Program will be maintained. The licensee states that WBNs snubber program manager provides oversight of the TRM snubber program implementation for both visual and functional testing, and the TRM implementation procedures are written and approved in accordance with the TVA Nuclear Quality Assurance Program. In addition to this, the NRC has endorsed the use of ASME OM Code, Subsection ISTD for snubber inservice examination and testing in 10 CFR 50.55a(b)(3)(v). ISTD states that the Owners responsibility includes qualification of personnel who perform and evaluate examinations and tests in accordance with the Owners quality assurance program. These requirements are similar to the TRM requirements. The staff finds that the proposed alternative to use TRM for snubber visual examination and functional testing without involving the ANII in these activities provides an acceptable level of quality and safety.

Record of snubber examinations and testing ASME Code,Section XI, IWA-6200, provides the requirements for snubber examination and test summary report preparation for snubber inservice examination and test documentation.

IWA-6230 requires owners to prepare an Owners Report for Inservice Inspection, Form NIS-1 for preservice and inservice examination of Class 1 and 2 pressure retaining components and their supports and submit the report to the NRC. The WBN Quality Assurance Program maintains records of snubber inspections and tests performed in accordance with the TRM and its implementing procedures. These records are available for review to demonstrate the acceptability of snubbers at WBN. In addition to this, the NRC has endorsed the use of ASME OM Code, Subsection ISTD for snubber inservice examination and testing. ISTD requirements for snubber examination and test summary report preparation are similar to the TRM requirements.

Therefore, the licensee proposed method of preparing and maintaining records of snubber examinations and tests provides an acceptable level of quality and safety and is acceptable.

Based on the above discussions, the staff finds that snubber visual examinations and functional testing, conducted in accordance with TRM TR 3.7.3, 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 visual inspection and functional testing. It should be noted that in authorizing Relief Request SNBR-1, TRM TR 3.7.3 becomes a regulatory requirement that may be used in lieu of ASME Code,Section XI requirements for performing inservice inspection and testing of snubbers.

Any changes to TRM 3.7.3 requirements that deviate from ASME Code requirements must be reviewed and approved by the NRC staff for authorization pursuant to 10 CFR 50.55a or as an exemption pursuant to 10 CFR 50.12.

4.0 CONCLUSION

Based on the information provided, the staff concludes that the proposed alternative to use TRM TR 3.7.3 for snubber visual inspection and functional testing provides an acceptable level of quality and safety. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), the licensees alternative for snubber visual inspection and functional testing is authorized for the WBN, Unit 1 second 10-year ISI interval, which started on May 27, 2007, and is scheduled to be completed by May 26, 2017.

5.0 REFERENCES

U.S. Code of Federal Regulations, Domestic Licensing of Production and Utilization Facilities, Part 50, Chapter I, Title 10, Energy, Section 50.55a, Codes and standards.

Generic Letter 90-09, Alternative Requirements for Snubber Visual Inspection Intervals and Corrective Actions, dated December 11, 1990.

American Society of Mechanical Engineers Boiler and Pressure Vessel Code,Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components.

American Society of Mechanical Engineers Operation and Maintenance Code, Inservice Testing of Nuclear Power Plant Components.

Letter from J. D. Smith, of Tennessee Valley Authority, to NRC, Docket 50-30: Watts Bar Nuclear Plant (WBN) - Unit 1 - Updated Inservice Inspection (ISI) Program for Second 10-year Interval and request for Relief Nos. PDI-2, PDI-4, and SNBR-1, dated February 07, 2007.

Letter from J. D. Smith, of Tennessee Valley Authority, to NRC Watts Bar Nuclear Plant (WBN) -

Unit 1 - American Society of Mechanical Engineers (ASME) Inservice Inspection (ISI) Program Request for Relief SNBR Response to Request for Additional Information (TAC No. MD4450),"

dated May 9, 2007.

Principal Contributors: Gurjendra S. Bedi Date: