ML032471340
| ML032471340 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 08/29/2003 |
| From: | Abney T Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| R08 030829 636 | |
| Download: ML032471340 (26) | |
Text
R08 030829 636 August 29, 2003 10 CFR 50.55a(a)(3)(i) and (ii)
U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Stop: OWFN P1-35 Washington, D.C. 20555 Gentlemen:
In the Matter of ) Docket No. 50-259 Tennessee Valley Authority )
BROWNS FERRY NUCLEAR PLANT (BFN) - UNIT 1 - AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) SECTION XI, SUBSECTION IWE, REQUIREMENTS FOR CLASS MC AND METALLIC LINERS OF CLASS CC COMPONENTS OF LIGHT-WATER COOLED PLANTS, REQUESTS FOR RELIEF In accordance with 10 CFR 50.55a(a)(3)(i) and (ii), TVA is requesting relief from certain requirements specified in the ASME Section XI Code, Subsection IWE, of the 1992 Edition, 1992 Addenda. Subsection IWE applies to Code Class MC (metal containment) pressure retaining components and metallic shell and penetration liners of Code Class CC (concrete containment) pressure retaining components and their integral attachments.
TVA seeks relief from the requirements described below. A detailed discussion and justification for each relief request are included in the enclosure to this letter.
CISI-1: Requests relief in accordance with 10 CFR 50.55a(a)(3)(ii) to not perform VT-3 visual examinations of seals and gaskets of Class MC components.
U.S. Nuclear Regulatory Commission Page 2 August 29, 2003 CISI-2: Requests relief in accordance with 10 CFR 50.55a(a)(3)(i) to not perform VT-2 visual examinations for leakage during Appendix J leak rate tests following repair, replacement, or modification activities.
CISI-3: Requests relief in accordance with 10 CFR 50.55a(a)(3)(ii) to not perform successive examinations of metal containment areas that have been repaired and are acceptable for continued service.
TVA has determined that the proposed alternatives would provide an acceptable level of quality and safety. TVA requests NRC review and approval of these relief requests to support Containment Inservice Inspections required prior to restart of BFN Unit 1. An NRC response is requested by March 1, 2004, to support BFN Unit 1 restart efforts.
There is established precedent for these relief requests.
Requests for relief 1-CISI-1, -2, and -3 are consistent with previously approved relief requests for BFN Units 2 and 3, submitted by TVA letter dated June 12, 2001, and approved by the NRC by letter dated August 6, 2001.
There are no commitments contained in this letter. If you should have any questions concerning this matter, please telephone me at (256) 729-2636.
Sincerely, Original signed:
T. E. Abney Manager of Licensing and Industry Affairs
U.S. Nuclear Regulatory Commission Page 3 August 29, 2003 DTL:MJB:BAB Enclosure cc (Enclosure):
M. J. Burzynski, BR 4X-C R. G. Jones, NAB 1A-BFN J. E. Maddox, LP 6A-C T. J. Niessen, PAB 1A-BFN D. C. Olcsvary, LP 6A-C J. R. Rupert, NAB 1A-BFN K. W. Singer, LP 6A-C M. D. Skaggs, POB 2C-BFN J. Valente, NAB 1E-BFN E. J. Vigluicci, ET 11A-K NSRB Support, LP 5M-C s:\lic\submit\subs\Unit 1 Relief Request CISI 1 2 3.doc
ENCLOSURE TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT 1 AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) SECTION XI, SUBSECTION IWE, CONTAINMENT INSPECTION PROGRAM (FIRST TEN-YEAR INSPECTION INTERVAL)
REQUESTS FOR RELIEF 1-CISI-1, -2, and -3 (See Attached)
TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT 1 ASME SECTION XI, CONTAINMENT (IWE) INSPECTION PROGRAM (FIRST TEN-YEAR INSPECTION INTERVAL)
REQUEST FOR RELIEF 1-CISI-1 Executive Summary: The Browns Ferry Unit 1 ASME Section XI containment inspection program is currently under the requirements of the 1992 Edition with the 1992 Addenda of Section XI. ASME Section XI, 1992 Edition, 1992 Addenda, Subsection IWE requires a visual examination, VT-3, of containment seals and gaskets. Examination of most seals and gaskets require the joints to be disassembled. Note 1 for Examination Category E-D was modified in the 1992 Edition, 1993 Addenda, of ASME Section XI to state that sealed or gasket connections need not be disassembled solely for performance of examinations. Absent disassembly, most of the surface of the seals and gaskets would be inaccessible, and therefore, examination would not provide useful information of gasket or seal condition.
Containment airlocks, hatches, electrical penetrations, and flanged connections are required to be periodically leak tested in accordance with the requirements of 10 CFR 50, Appendix J. Unacceptable degradation of seal or gasket material would be detected during this testing via an increase in the penetration leakage rate.
Penetrations failing to meet established acceptance criteria would require application of corrective measures and re-testing. Repair and E-2
replacement of seals and gaskets is not subject to Code rules in accordance with Paragraph IWA-4111 (b)(5) of the 1992 Edition, 1992 Addenda of ASME Section XI.
Visual examination of seals and gaskets in accordance with Subsection IWE results in hardship or difficulty without a compensating increase in safety or quality. The requirement to examine seals and gaskets was removed in the 1998 Edition of ASME Section XI. Therefore, pursuant to 10 CFR 50.55a(a)(3)(ii) TVA requests that relief be granted.
This request for relief is consistent with requests for relief submitted for Browns Ferry Units 2 and 3 dated June 12, 2001. NRC approved TVAs requests for relief by letter dated August 6, 2001.
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Unit: Unit 1 System: Containment System Components: Various Seals and Gaskets ASME Code Class: MC Section XI Edition: 1992 Edition, 1992 Addenda Code Table: IWE-2500-1 Examination Category: E-D, Seals, Gaskets, and Moisture Barriers Examination Item Number: E5.10 (Seals), and E5.20 (Gaskets)
Code Requirement: Table IWE-2500-1, Examination Category E-D, Item Numbers E5.10 and E5.20, requires seals and gaskets on airlocks, hatches, and other devices to be VT-3 visually examined once each inspection interval to assure containment leak-tight integrity.
Code Requirements From Which Relief Is Requested: Relief is requested from performing the visual examination, VT-3, on the above identified metal containment seals and gaskets.
List Of Items Associated With The Relief Request: Seals and gaskets of Class MC pressure retaining components, Examination Category E-D, Item Numbers E5.10 and E5.20 of Table IWE-2500-1.
Basis For Relief E-4
Request: The design configuration of the connections which include seals and gaskets precludes visual examination of the seals and gaskets without disassembly of the connection. Testing the seals and gaskets in accordance with 10 CFR 50, Appendix J, provides adequate assurance of the leak-tight integrity of the seals and gaskets.
Alternative Examination: The leak-tight integrity of seals and gaskets is tested in accordance with 10 CFR 50, Appendix J. Type B testing is performed at least once each in-service inspection interval as required by 10 CFR 50, Appendix J, in addition to the Type B tests performed prior to disassembly (unless excepted based on performance history) and after re-assembly.
Appendix J, Type A tests provide additional assurance that there is no significant leakage through the containment pressure boundary. No additional alternatives are proposed.
Justification For The Granting Of Relief: 10 CFR 50.55a currently requires use of either the 1992 Edition of ASME Section XI, Subsection IWE, with the 1992 Addenda, or the 1995 Edition of ASME Section XI, Subsection IWE, with the 1996 Addenda, as modified and supplemented further therein for the performance of containment inspections. BFN Unit 1 is currently under the 1992 Edition of ASME Section XI, Subsection IWE with the 1992 Addenda. These examinations include visual examinations of seals and gaskets. The penetrations discussed below contain seals and gaskets:
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Electrical Penetrations Electrical penetrations use a header plate(s), or header plate canister assembly, welded to the containment penetration nozzle. Modules through which electrical conductors pass are installed in the header plate(s).
The electrical penetrations installed at BFN Unit 1 are manufactured by Physical Sciences, General Electric, and Conax (three BFN Unit 1 Physical Sciences penetrations are being replaced with Conax penetrations during the current outage). Physical Sciences penetrations are canister type and consist of compressed glass penetration seals and hermetically-sealed connector receptacles mounted in steel header plates. The seals of this type of penetration are inaccessible. The General Electric penetrations installed are modular in design. Modular type General Electric penetrations are sealed by redundant epoxy barriers and metallic or elastomer O-rings. The modular General Electric penetration seals are completely inaccessible without disconnecting cabling and removal of the modules. Conax penetrations use a set of compression fittings and may include sealant compounds and/or O-rings. The Conax penetration seals are completely inaccessible without disconnecting cabling and removal of the modules.
Containment Personnel Airlocks, Drywell Head, Equipment Hatches, and Flanges and Hatches The personnel airlock doors utilize an inner and outer door with O-ring seals to ensure leak tight integrity.
These airlocks also contain other gaskets and seals for items such as E-6
the handwheel shaft seals, electrical penetrations, and equalizing valves which require disassembly to gain access to the gaskets and seals. The drywell head, equipment hatches, and all flanges and hatches utilize double seals or gaskets.
Seals and gaskets receive a 10 CFR 50, Appendix J, Type B test. As noted in 10 CFR 50, Appendix J, the purpose of the Type B test is to measure leakage of containment penetrations whose design incorporates resilient seals, gaskets, or sealant compounds or flexible metal seal assemblies.
Examination of seals and gaskets require the joints, which are proven adequate through Appendix J testing, to be disassembled. For electrical penetrations, this would involve performance of an Appendix J, Type B test prior to disassembly (unless excepted based on performance history); de-termination of cables at electrical penetrations if enough cable slack is not available; disassembly of the joint (if designed to permit disassembly); removal and VT-3 visual examination of the seals and gaskets; re-assembly of the joint; re-termination of the cables, if necessary; post maintenance testing of the cables; and performance of an Appendix J, Type B test upon final assembly.
Disassembly and reassembly of these penetrations imposes the risk that the equipment could be damaged.
Further, a VT-3 examination does not ensure that these items, when reassembled, will not leak.
Note 1 for Examination Category E-D was modified in the 1992 Edition, 1993 Addenda, of ASME Section XI to state that sealed or gasket E-7
connections need not be disassembled solely for performance of examinations. However, without disassembly, all of the surface of the seals and gaskets would be inaccessible.
Containment personnel airlocks receive a Type B test within seven days after each opening. For periods of multiple containment entries where the airlock doors are routinely used for access more frequently than once every seven days, door seals may be tested once every thirty days. Since the Type B tests assure the leak tight integrity of primary containment, the performance of a VT-3 visual examination would not increase the level of safety or quality.
Type B tests are required prior to disassembly (unless excepted based on performance history) and following re-assembly of all equipment hatches.
Since the Type B tests assure the leak-tight integrity of primary containment, the performance of a VT-3 visual examination would not increase the level of safety or quality. Further, prior to hatch re-assembly, the O-ring seals are visually inspected as a normal maintenance practice.
For other flanges and hatches, should the connection(s) be disassembled, a Type B test is required prior to disassembly (unless excepted based on performance history) and upon final assembly prior to startup. Since the Type B tests assure the leak tight integrity of primary containment, the performance of the VT-3 visual examination would not increase the level of safety or quality.
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Unacceptable degradation of airlock, hatch, or flange seals/gaskets would be revealed during Appendix J testing. If the measured leakage rate of these penetrations exceeds established limits, corrective action would be taken and the component re-tested. Repair or replacement of seals and gaskets is not subject to ASME Section XI rules in accordance with Paragraph IWA-4111(b)(5).
Containment leakage is verified by 10 CFR 50, Appendix J, Type A tests.
Although the Type A test does not verify individual penetration leakage, it does provide additional assurance that there is no significant leakage through the containment pressure boundary, which includes all sealed penetrations.
The visual examination of seals and gaskets in accordance with Table IWE-2500-1, Examination Category E-D, Item Numbers E5.10 and E5.20, would result in a hardship or unusual difficulty without a compensating increase in the level of quality and safety. Testing the seals and gaskets in accordance with 10 CFR 50, Appendix J provides adequate assurance of the leak-tight integrity of the seals and gaskets.
In addition, the requirement to examine seals and gaskets has been removed in the 1998 Edition of ASME Section XI Code. Therefore, pursuant to 10 CFR 50.55a(a)(3)(ii), TVA requests that relief be granted.
This request for relief is consistent with requests for relief submitted for Browns Ferry Units 2 and 3 dated June 12, 2001. NRC approved TVAs E-9
requests for relief by letter dated August 6, 2001.
Implementation Schedule: This request for relief will be implemented during the first ten-year containment inspection interval for BFN Unit 1.
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TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT 1 ASME SECTION XI, CONTAINMENT (IWE) INSPECTION PROGRAM (FIRST TEN-YEAR INSPECTION INTERVAL)
REQUEST FOR RELIEF 1-CISI-2 Executive Summary: The Browns Ferry Unit 1 ASME Section XI containment inspection program is under the requirements of the 1992 Edition with the 1992 Addenda of the ASME Section XI Code. Paragraph IWE-5240 of the 1992 Edition, 1992 Addenda, of ASME Section XI requires a visual examination, VT-2, following repair, modification, or replacement of pressure retaining components.
Visual examinations (VT-2) are conducted to detect evidence of leakage from pressure retaining components, with or without leakage collection systems, during the conduct of a system pressure test.
Visual examinations (VT-2) are principally performed to locate water or steam leaks from pressure retaining components. Visual examination for evidence of air leakage does not provide effective detection of leakage. Table IWE-2500-1, Examination Category E-P, requires 10 CFR 50, Appendix J testing for all containment pressure retaining components. Appendix J provides requirements for testing as well as acceptable leakage criteria.
Additionally, 10 CFR 50.55a(b)(2)(ix)(E) requires that a General Visual examination of the containment, as required by Subsection IWE, be performed each period. This examination would identify structural degradation that may contribute to leakage. Repairs E-11
and replacements, including modifications, must be performed in accordance with Article IWA-4000, which provides additional assurance of structural integrity of the containment. Performance of a VT-2 visual examination, in addition to the above testing requirements, would not provide additional assurance of detection of containment pressure boundary leakage. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i)
TVA requests that relief be granted.
This request for relief is consistent with requests for relief submitted for Browns Ferry Units 2 and 3 dated June 12, 2001. NRC approved TVAs requests for relief by letter dated August 6, 2001.
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Unit: Unit 1 System: Containment System Components: Various Pressure Retaining Components ASME Code Class: MC Section XI Edition: 1992 Edition, 1992 Addenda Code Table: IWE-2500-1 Examination Category: E-P, All Pressure Retaining Components Examination Item Number: E9.10, Containment Vessel, Pressure Retaining Boundary Code Requirement: Table IWE-2500-1, Examination Category E-P, Item Number E9.10, requires a system leakage test be performed for each repair, modification, or replacement.
Paragraph IWE-5240 states that the requirements of Paragraph IWA-5240 are applicable for visual examinations performed following repair, modification, or replacement.
Paragraph IWA-5240 provides requirements for the performance of a VT-2 visual examination for the detection of leakage.
Code Requirements From Which Relief Is Requested: Relief is requested from performing the VT-2 visual examination of Paragraph IWA-5240 in connection with system pressure testing following repair, modification, or replacement as required by Paragraph IWE-5240.
List Of Items E-13
Associated With The Relief Request: All Class MC components which require repair, modification, or replacement and are subject to the system pressure tests of Table IWE-2500-1, Examination Category E-P, Item Number E9.10 and Article IWE-5000.
Basis For Relief Request: Table IWE-2500-1, Examination Category E-P, Item Number E9.10, requires that a leakage test be performed in accordance with 10 CFR 50, Appendix J following each repair, modification, or replacement.
Performance of the Appendix J testing would detect any leakage which may exist in the containment pressure retaining boundary. In addition, the requirements of Article IWA-4000 must be met following repairs and replacements, including modifications. Performance of a VT-2 visual examination, as required by Paragraph IWE-5240, does not provide additional assurance of detection of containment pressure boundary leakage.
Alternative Examination: In those cases where TVA elects not to perform a VT-2 visual examination of repaired or replaced areas during the 10 CFR 50, Appendix J leak rate testing, a VT-1 visual examination will be performed during or following the 10 CFR 50, Appendix J leak rate testing.
Justification For The Granting Of Relief: 10 CFR 50.55a currently requires use of either the 1992 Edition of ASME Section XI, Subsection IWE, with the 1992 Addenda, or the 1995 Edition of ASME Section XI, Subsection IWE, with the 1996 Addenda, as modified and E-14
supplemented further therein for performance of containment examinations. BFN Unit 1 is currently under the 1992 Edition of ASME Section XI, Subsection IWE with the 1992 Addenda. Paragraph IWE-5210 states that except as noted within Paragraph IWE-5240, the requirements of Article IWA-5000 are not applicable to Class MC or Class CC components. Paragraph IWE-5240 states that the requirements of Paragraph IWA-5240 (corrected from IWA-5246 to IWA-5240 in the 1993 Addenda) for visual examinations are applicable. Paragraph IWA-5240 identifies requirements for performance of a VT-2 visual examination. Visual examinations (VT-2) are conducted to detect evidence of leakage from pressure retaining components, with or without leakage collection systems, during the conduct of a system pressure test. In addition, personnel performing VT-2 visual examinations are required to be qualified in accordance with Subarticle IWA-2300 of ASME Section XI.
Table IWE-2500-1, Examination Category E-P, Item Number E9.10, identifies the examination method of 10 CFR 50, Appendix J and does not specifically identify a VT-2 visual examination. 10 CFR 50, Appendix J provides requirements for testing as well as acceptable leakage criteria.
These tests are performed by qualified Appendix J test personnel and utilize calibrated equipment to determine leak rate acceptability.
Additionally, 10 CFR 50.55a(b)(2)(ix)(E) requires a General Visual examination of the containment each period that would identify structural degradation that may contribute to leakage.
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Repairs and replacements, including modifications, to the containment pressure retaining boundary and to integral attachments must be performed in accordance with Article IWA-4000. This article requires, among other things, preparation of a repair and replacement plan; requires repairs and installation of replacements, including performance of nondestructive examinations, to be performed in accordance with the original edition or later editions of the Construction Code or Section III; and requires performance of preservice inspections in accordance with Subsection IWE. Repairs and replacements of pressure retaining MC components and their integral attachments at BFN are performed in accordance with TVAs Repair and Replacement Program. This program specifies the repair methods and nondestructive examinations necessary to ensure that the original quality and construction requirements of the containment vessel are met.
Performance of the Appendix J testing will detect leakage which may exist in the containment pressure retaining boundary. Performance of the General Visual examination and compliance with Article IWA-4000 will provide added assurance of the structural integrity of the containment pressure retaining boundary. Performance of a visual examination (VT-2) in addition to these requirements would not provide additional assurance for detection of containment pressure boundary leakage.
Pressure testing in accordance with 10 CFR 50, Appendix J, provides an adequate level of quality.
Therefore, pursuant to 10 CFR E-16
50.55a(a)(3)(i), TVA requests that relief be granted.
This request for relief is consistent with requests for relief submitted for Browns Ferry Units 2 and 3 dated June 12, 2001. NRC approved TVAs requests for relief by letter dated August 6, 2001.
Implementation Schedule: This request for relief will be implemented during the first ten-year containment inspection interval for BFN Unit 1.
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TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT 1 ASME SECTION XI, CONTAINMENT (IWE) INSPECTION PROGRAM (FIRST TEN-YEAR INSPECTION INTERVAL)
REQUEST FOR RELIEF 1-CISI-3 Executive Summary: Paragraphs IWE-2420(b) and IWE-2420(c) of the 1992 Edition, 1992 Addenda, of ASME Section XI require that when component examination results require evaluation of flaws, evaluation of areas of degradation, or repairs in accordance with Article IWE-3000, and the component is found to be acceptable for continued service, the areas containing such flaws, degradation, or repairs shall be reexamined during the next inspection period listed in the schedule of the inspection program of Paragraph IWE-2411 or Paragraph IWE-2412, in accordance with Table IWE-2500-1, Examination Category E-C.
The purpose of a repair is to restore the component to an acceptable condition for continued service.
Furthermore, if the repair area is subject to accelerated degradation, it would require augmented examination in accordance with Paragraph IWE-1241 and Table IWE-2500-1, Examination Category E-C.
The successive examination of repaired areas in accordance with Paragraphs IWE-2420(b) and IWE-2420(c) constitutes a burden on TVA without a compensating increase in quality or safety.
Paragraphs IWB-2420(b), IWC-2420(b),
and IWD-2420(b) for Class 1, 2, and 3 components, respectively, do not require a repaired component be E-18
subject to successive examination requirements. Additionally, the requirement to perform successive examinations of repaired areas in accordance with Paragraphs IWE-2420(b) and IWE-2420(c) has been removed in the 1998 Edition of ASME Section XI. The requirement to perform successive examinations of repaired areas in accordance with Subsection IWE is a burden without a compensating increase in safety or quality. Therefore, pursuant to 10 CFR 50.55a(a)(3)(ii), TVA requests that relief be granted.
This request for relief is consistent with requests for relief submitted for Browns Ferry Units 2 and 3 dated June 12, 2001. NRC approved TVAs requests for relief by letter dated August 6, 2001.
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Unit: Unit 1 System: Containment System Components: Various Containment Components ASME Code Class: MC Section XI Edition: 1992 Edition, 1992 Addenda Code Table: N/A Examination Category: N/A Examination Item Number: N/A Code Requirement: Paragraph IWE-2420(b) requires that when component examination results require evaluation of flaws, evaluation of areas of degradation, or repairs in accordance with Article IWE-3000, and the component is found to be acceptable for continued service, the areas containing such flaws, degradation, or repairs shall be reexamined during the next inspection period listed in the schedule of the inspection program of Paragraph IWE-2411 or Paragraph IWE-2412, in accordance with Table IWE-2500-1, Examination Category E-C.
In accordance with Paragraph IWE-2420(c), when the reexaminations required by Paragraph IWE-2420(b) reveal that the flaws, areas of degradation, or repairs remain essentially unchanged for three consecutive inspection periods, the areas containing such flaws, degradation, or repairs no longer require augmented examination in accordance with Table IWE-2500-1, Examination Category E-C.
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Code Requirements From Which Relief Is Requested: Relief is requested from the requirement of Paragraphs IWE-2420(b) and IWE-2420(c) to perform successive examination of repaired areas.
List Of Items Associated With The Relief Request: All Class MC components and their integral attachments which require repairs and are found to be acceptable in accordance with Article IWE-3000 for continued service subsequent to the repairs.
Basis For Relief Request: Examination results, which detect flaws or areas of degradation which exceed the acceptance criteria of IWE-3000, require engineering evaluation, repair, or replacement of the flaw or areas of degradation.
Paragraphs IWE-2420(b) and IWE-2420(c) require performance of successive examinations for flaws or areas of degradation accepted for continued service based on engineering evaluation or repair.
The purpose of a repair is to restore the component to an acceptable condition for continued service in accordance with the acceptance standards of Article IWE-3000. If the repair has restored the component to an acceptable condition, successive examinations are not warranted.
Alternative Examination: Successive examinations in accordance with Paragraphs IWE-2420(b) and IWE-2420(c) will not be required for areas repaired in accordance with Article IWA-4000. Successive examinations will be performed in E-21
accordance with Paragraphs IWE-2420(b) and IWE-2420(c) for components whose examination results detect flaws or areas of degradation that exceed the acceptance criteria of IWE-3000 and are found acceptable for continued service without repair based on an engineering evaluation.
Justification For The Granting Of Relief: 10 CFR 50.55a currently requires use of either the 1992 Edition of ASME Section XI, Subsection IWE, with the 1992 Addenda, or the 1995 Edition of ASME Section XI, Subsection IWE, with the 1996 Addenda, as modified and supplemented further therein for the performance of containment inspections. BFN Unit 1 is currently under the 1992 Edition of ASME Section XI, Subsection IWE with the 1992 Addenda. Examination results, which detect flaws or areas of degradation which exceed the acceptance criteria of Article IWE-3000, require engineering evaluation, repair, or replacement of the flaw or areas of degradation. The purpose of a repair is to restore the component to an acceptable condition for continued service in accordance with the acceptance standards of Article IWE-3000. Paragraph IWA-4150 requires the owner to conduct an evaluation of the suitability of the repair including consideration of the cause of failure.
If a repair has restored the component to an acceptable condition, successive examinations are not warranted. If the repair was not suitable, then the repair does not meet Code requirements and the component is not acceptable for continued service. Paragraphs IWB-2420(b), IWC-2420(b), and E-22
Paragraph IWD-2420(b) for Class 1, 2, and 3 components, respectively, do not require a repair to be subject to successive examination requirements.
Furthermore, if the repair area is subject to accelerated degradation, it would require augmented examination in accordance with Paragraph IWE-1241 and Table IWE-2500-1, Examination Category E-C.
The successive examination of repairs in accordance with Paragraphs IWE-2420(b) and IWE-2420(c) constitutes a burden on TVA without a compensating increase in quality or safety.
The requirement to perform successive examinations of repaired areas has been removed from Paragraphs IWE-2420(b) and IWE-2420(c) in the 1998 Edition of ASME Section XI.
Therefore, pursuant to 10 CFR 50.55a(a)(3)(ii), TVA requests that relief be granted.
This request for relief is consistent with requests for relief submitted for Browns Ferry Units 2 and 3 dated June 12, 2001. NRC approved TVAs requests for relief by letter dated August 6, 2001.
Implementation Schedule: This request for relief will be implemented during the first ten-year containment inspection interval for BFN Unit 1.
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