ML071290561
| ML071290561 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 05/09/2007 |
| From: | James Smith Tennessee Valley Authority |
| To: | Document Control Desk, NRC/NRR/ADRO |
| References | |
| TAC MD4450 | |
| Download: ML071290561 (10) | |
Text
May 9, 2007 10 CFR 50.55a U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 Gentlemen:
In the Matter of ) Docket No. 50-390 Tennessee Valley Authority )
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)
The purpose of this letter is to respond to the NRCs request for additional information received from the Watts Bar Project Manager by electronic mail (e-mail) on April 19, 2007, concerning the subject request for relief. TVA submitted the request for relief on February 7, 2007.
There are no regulatory commitments associated with this submittal. If you have any questions concerning this matter, please call me at (423) 365-1824.
Sincerely, Original Signed by J. D. Smith Manager, Site Licensing and Industry Affairs (Acting)
Enclosure cc: See Page 2
U.S. Nuclear Regulatory Commission Page 2 May 9, 2007 Enclosure cc (Enclosure):
NRC Resident Inspector Watts Bar Nuclear Plant 1260 Nuclear Plant Road Spring City, Tennessee 37381 Mr. Brendan T. Moroney, Project Manager U.S. Nuclear Regulatory Commission MS 08G9a One White Flint North 11555 Rockville Pike Rockville, Maryland 20852-2738 U.S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth St., SW, Suite 23T85 Atlanta, Georgia 30303
WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME)
INSERVICE INSPECTION (ISI) PROGRAM REQUEST FOR RELIEF SNBR-1 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION By letter dated February 7, 2007, TVA submitted for staff review and approval the proposed Request for Relief SNBR-1. This request was seeking relief from the requirements of ASME Code,Section XI, for the second 10-year inservice inspection (ISI) interval to WBN Unit 1. In order to complete the review, the staff has requested by electronic mail on April 19, 2007, the following additional information:
QUESTION 1 On Page E3-3, Alternate Examinations, fourth paragraph, the licensee states Snubber examination and testing data will be maintained in accordance with the requirement of TR 3.7.3...
Please identify and provide the section(s) of TR 3.7.3 which provide the requirements for maintaining snubber examination and testing data.
Response
No specific wording, or sections, in WBNs Technical Requirements Manual (TRM) TR 3.7.3 directly require maintenance of snubber examination and testing data. However, aspects of the TRM TR 3.7.3 requirements indirectly dictate that TVA maintain suitable examination and test data records in order to comply with the requirements of the whole TR based program. Records of snubber examinations and tests are maintained through program administrative controls as follows.
The implementing procedures for the inspections required by TRM TR 3.7.3 are 1-TRI-0-5, Snubber Visual Inspection (Hydraulic and Mechanical), 1-TRI-0-7, Snubber Functional Testing (Mechanical Snubbers), and 1-TRI-0-8, Snubber Functional Testing (Paul Monroe Snubbers). QA examination records are maintained in accordance with these implementing procedures. 1-TRI-0-5 section 8.1, 1-TRI-0-7 section 8.1, and 1-TRI-0-8 section 8.1 state that the Data Package is a QA record, and is handled in accordance with the Document Control and Records Management Program.
Specific details of the Document Control and Records Management Programs are contained in SPP-2.3, Document Control, and SPP-2.4, Records Management.
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QUESTION 2 On Page E3-7, Attachment, Item 5, fourth column, the licensee states WBN TRM TR 3.7.3 requirements for visual examination failure are comparable to OM-4, Section 2.3.4. Please identify and provide the section(s) of TR 3.7.3 which provide the requirements for visual examination failure.
Response
TRM TR 3.7.3, Table 3.7.3-1, Item 2 states the requirements for determining the cause of unacceptability for failed examinations.
This paragraph states that snubbers which appear inoperable as a result of visual inspections shall be classified as unacceptable. These snubbers may only be reclassified as acceptable when 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.
TRM TR 3.7.3 note 2, describes the additional action to be taken to address a failed visual examination. 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 in the unit. Mechanical snubbers shall have met the acceptance criteria subsequent to their most recent service, and the freedom-of-motion test must have been performed within 12 months before being installed in the unit.
These requirements are implemented by procedure 1-TRI-0-5, Snubber Visual Inspection (Hydraulic and Mechanical).
QUESTION 3 On Page E3-9, Attachment, Item 5, fourth column, the licensee states WBN TRM TR 3.7.3 states that the unacceptable snubbers may be categorized into failure mode group(s). A failure mode group shall include all unacceptable snubbers that have a given failure mode and all other snubbers subject to that same failure. Please identify and provide the section(s) of TR 3.7.3 which provide the requirements for failure mode groups.
Response
TRM TR 3.7.3 Table 3.7.3-5, note 2 describes the failure mode evaluation requirement and the subsequent evaluation of operability of snubbers with the same failure mode as the failed snubber. Specifically, An engineering evaluation shall be made of each failure to meet the functional test criteria to determine E-2
the cause of the failure. The results of this evaluation shall be used, if applicable, in selecting snubbers to be tested in an effort to determine the OPERABILITY of other snubbers irrespective of the type which may be subject to the same failure mode.
TRM TR 3.7.3 Table 3.7.3-5, note 4 describes the actions taken when a failure is attributed to the manufacturer or design deficiency. If any snubber selected for functional testing either fails to lock up or fails to move, i.e., frozen-in-place, the cause will be evaluated and, if caused by manufacturer or design deficiency, all snubbers of the same type subject to the same defect shall be functionally tested. This testing requirement shall be independent of the requirements stated in Table 3.7.3-4 for snubbers not meeting the functional test acceptance criteria.
QUESTION 4 On Page E3-4, Justification for the Granting of Relief, second paragraph, the licensee states Examination, testing, repair and replacement of snubbers are currently performed in accordance with TR 3.7.3, which utilizes the guidance provided by NRC in Generic Letter (GL) 90-09. The OM Code referenced by ASME Section XI has a different basis for examination (Failure mode groups) and testing plan (10 percent, 37, or 55). It is impractical to implement both plans... Please verify the correctness of this statement given that (1) GL 90-09 provides guidance only for visual examination, not for testing, and repair and replacement of snubbers; and (2) ASME Section XI, OM-4 testing plans (10 percent, 37 or 55) are similar to the testing plan implemented by TR 3.7.3.
Response
While there are similarities between the existing TRM TR 3.7.3 snubber program and the OM Code as presented in Request for Relief SNBR-1, there are variations (e.g. the different testing plan sizes possible under OM Code compared to TRM TR 3.7.3) which would result in duplication of effort by mandating two separate snubber inspection programs. Imposition of an additional program, OM Code, for snubber examination and testing would not increase safety; however, it would be impractical to implement.
The statement regarding TRM TR 3.7.3 utilizing the guidance provided in GL 90-09 was made to demonstrate that the TRM TR 3.7.3 snubber visual examination frequencies are consistent with this guidance document. In addition to the visual examinations, TRM TR 3.7.3 also provides requirements for testing, and repair and replacement of snubbers.
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QUESTION 5 On Pages E3-7 through E3-9 of Attachment, in fourth column, the licensee references WBN TRM 3.7.3. The correct document is WBN TRM TR 3.7.3. Please verify.
Response
WBN TRM TR 3.7.3 is the correct document reference.
QUESTION 6 On Page E3-7, Attachment, Item 3, fourth column, the licensee states WBN TRM TR 3.7.3 snubber inspections are performed by personnel who are specifically trained and certified to perform snubber visual examination. Visual acuity of inspectors is also verified. Please provide justification for this statement and explain how the TRM TR 3.7.3 visual examination method is equivalent to the VT-3 visual examination method described in IWA-2213.
Response
Visual examination criteria are included in procedure 1-TRI-0-5.
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 Section XI, IWA-2213. Excerpts of procedure 1-TRI-0-5 E-4
Sections 5.0 and 6.0 are provided in the Attachment to this enclosure. 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 examination method specified in ASME Section XI.
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Attachment Excerpts of Procedure 1-TRI-0-5, Snubber Visual Inspection (Hydraulic and Mechanical) 5.0 ACCEPTANCE CRITERIA A. Visual inspection verifies the following:
- 1. There are no visual indications of damage or impaired operability.
- 2. Bolts attaching snubber to foundation or supporting structure are secure.
- 3. Snubbers attached to sections of safety-related systems that have experienced unexpected potentially damaging transients since last inspection period are evaluated for possibility of concealed damage and are functionally tested, if applicable, to confirm operability.
6.0 PERFORMANCE NOTE 1 Scope of inspection in the following step includes snubber, pipe clamp bolts (if not covered by insulation), attachment to structural members, extension piece and connectors.
NOTE 2 The following two steps are performed concurrently.
[6] INSPECT snubber unit for structural integrity and any of the following physical damage:
A. Corrosion - Deep pits that visibly reduce cross sectional load bearing area of component.
B. Scratches - Scratches that visibly reduce cross sectional area or would restrict proper movement of snubber.
C. Bends/Deformation - Indications of interferences or possible transients to system or stepped-on condition.
D. Weld Damage - Weld cracking.
E. Base Plate Anchor Bolt/Grout - Anchor bolt/grout missing or damaged.
F. Pipe Clamp - Damaged or any indication of movement.
G. General Condition - Snubber/pivot pins covered with insulation, paint, condensation, glycol spill, oil, excessive dirt or fully extended/fully retracted snubbers (i.e., no stroke length available).
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[7] OBSERVE overall support in the proximity of the snubber to detect any support damage or degradation.
[8] DOCUMENT results of Steps [6] and [7] in ACCEPT STRUCT INTEG column on data sheet.
[9] INSPECT the following items for proper condition, and DOCUMENT results in FASTNRS SECURE column of data sheet.
A. All load pins for locking devices such as cotter pins, snap rings or jam nut and lock wire on position indicator tube screws.
B. End attachment bolts and lock wires, as applicable (if existing end attachment bolts have holes).
C. Clamp bolts for tightness, as applicable.
NOTE 1 Verification of no binding on small PSA snubbers may be accomplished by rotating snubber by hand a few degrees in both directions on its spherical bearings. Snubber should rotate freely.
NOTE 2 Appendix B explains four types of misalignment.
[10] INSPECT snubber connection alignment for the following items, and DOCUMENT results in ALIGN SAT column of data sheet.
A. Torsional binding.
B. Clamp binding.
C. Lateral misalignment.
D. Interference.
E. Frozen or dislodged spherical bearings.
F. Proper gap at bracket ears not more than 3/16 inch.
G. Spacer washers properly installed (beveled washers must have bevel facing the spherical bearing).
NOTE Steps [11], [12] and [13] are not applicable to mechanical snubbers.
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[11] INSPECT snubber for the following items affecting fluid integrity, and DOCUMENT results in ACCEPT FLUID INTEG column on data sheet.
A. Piston rod scratches, nicks or dents.
B. General snubber condition such as fluid ports, cleanliness, missing plug, etc.
C. Fluid leaks.
NOTE Remote reservoir and a portion of the tubing on Paul Munroe snubbers are located in upper containment. The following two items should be checked.
D. Tubing support structural integrity.
E. Fluid leaks on tubing and reservoir.
[12] IF fluid level in reservoir sight glass is less than maximum, THEN DOCUMENT in REMARKS column on data sheet.
[13] IF fluid level is not visible in reservoir sight glass, THEN INITIATE a WO to determine actual fluid level and for snubber functional testing to verify operability, as required, and DOCUMENT in REMARKS column on data sheet.
[14] DOCUMENT results of any visually inoperable snubber found in OPER VISUAL column on data sheet.
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