ML20248B044
| ML20248B044 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 05/27/1998 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20248B037 | List: |
| References | |
| NUDOCS 9806010156 | |
| Download: ML20248B044 (3) | |
Text
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UNITED STATES g
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NUCLEAR RECULATORY COMMISSION t
WASHINGTON, D.C. 30666-0001
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELIEF REQUEST FOR SNUBBER VISUAL EXAMINATION AND FUNCTIONAL TESTING DUKE ENERGY CORPORATION MCGUIRE NUCLEAR STATION. UNITS 1 AND 2 DOCKET NOS. 50-369 AND 50-370
1.0 INTRODUCTION
The Technical Specifications (TS) for McGuire Nuclear Station, Units 1 and 2, state that the inservice inspection of the American Society of Mechanical Engineers (ASME) Code Class 1,2, and 3 components shall be performed in accordance with Section XI of the ASME Boiler and Pressure Vessel Code (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 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 weeptable 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 pre-service examination requirements, set forth in the ASME Code,Section XI, " Rules for Inservice Inspection of Nuclear Power Plant Components," 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 i
modifications listed therein. The applicable edition of Section XI of the ASME Code for the McGuire Nuclear Station, Units 1 and 2, second 10-year inservice inspection (ISI) interval is the 1989 Edition.
Pursuant to 10 CFR 50.55a(g)(5), if the licensee determines that conformance with an examination requirement of Section XI of the ASME Code is not practical for its facility, information shall be submitted to the Commission in support of that determination and a request i
made for relief from the ASME Code requirement. After evaluation of the determination, pursuant to 10 CFR 50.55a(g)(6)(i), the. Commission may grant relief and may impose attemative requirements that are determined to be authorized by law, will not endanger life, property, or the common defense and security, and are otherwise in the public interest, giving l
due consideration to the burden upon the licensee that could result if the requirements were imposed.
9806010156 980527 PDR ADOCK 05000369 P
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. l By letter of December 17,1997, Duke Energy Corporation (DEC/the licensee) requested relief from the requirements of the ASME Code Section XI,1989 Edition, Article IWF-5000, Subsection IWF-5300, with regard to visual examination and functional testing of snubbers.
Subsection IWF-5300 references the first addenda to ASME/ ANSI OM-1987, Part 4 (OM-4) for such snubber activities. The licensee requested the continued use of the current TS requirements for snubber visual examination and functional testing, pursuant to 10 CFR 50.55a(a)(3)(i).
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2.0 BASIS FOR RELIEF The licensee stated that the current McGuire, Units 1 and 2, TS specify an adequate program i
for visual examination and functional testing for all safety-related snubbers. The snubber examinations and tests at McGuire, Units 1 and 2, are currently performed under TS Section 3/4.7.8, as amended in accordance with NRC Generic Letter (GL) 90-09, "Altemative Requirements for Snubber Visual Inspection Intervals and Corrective Actions," dated 1
December 11,1990. The licensee stated that the current inspection program, as defined by the TS, provides for a level of quality and safety equal to that of the OM-4. This is based on the fact that the attemative provides the same confidence level, as supported by GL 90-09.
Furthermore, the TS snubber program scope includes all safety-related snubbers, which encompasses all Code Class 1,2, and 3 snubbers that meet the ASME Section XI l
requirements.
The licensee further stated that the OM-4 requires failure mode grouping (FMG) of s'nubbers which fail visual examination. The existing TS requires that once a snubber fails, all snubbers I
in the population, rather than only those identified in the FMG, be placed in a shortened l
l inspection interval. The functional testing plan of OM-4 also includes the requirements of FMG.
In some cases, the functional testing plan of OM-4 allows for the reclassification of snubbers that are categorized in the same FMG, which includes the failed snubbers, as acceptable without further testing. The current program at McGuire, Units 1 and 2, requires additional testing for all failed snubbers until the desired confidence level is assured, with no allowances to l
reclassify the unacceptable snubbers. Based on the above, the OM-4 requirements may not be conservative as compared to the existing TS program. This is especially true for the large l
snubber population which exists at McGuire, Units 1 and 2 (over 300 per unit). Therefore, the i
licensee stated that the TS corrective action requirements are more conservative than those in the OM-4.
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3.0 EVALUATION l
The staff has reviewed the licensee's submittal pertaining to the relief request from the requirements of the ASME Code for visual examination and functional testing of snubbers.
The staff finds that the licensee's basis for relief is acceptable, because it provides the same confidence level, is in accordance with GL 90-09, and provides assurance that snubbers will function and protect the structural integrity of safety-related systems and components.
Therefore, the attemative provides an acceptable level of quality and safety.
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4.0 CONCLUSION
Based on the information provided, the staff has determined that the licensee has presented an adequate justification for the requested relief from the requirements of the ASME Code,1989 Edition,Section XI, Article IWF-5000 (which references OM-4), with regard to visual examination and functional testing of Code Class 1,2, and 3 snubbers. The staff has determined that the proposed attemative use of the TS requirement in Section 3/4.7.8 for the
- Code Class snubbers would provide an acceptable level of quality and safety. Therefore, Request for Relief No.97-005 is authorized, pursuant to 10 CFR 50.55a(a)(3)(i).
Principal Contributor: A. Lee Date:
May 27, 1998 9
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