ML20094B876
| ML20094B876 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 10/26/1995 |
| From: | Shell R TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9511010327 | |
| Download: ML20094B876 (4) | |
Text
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, w.1 LVA tenessee vaney Aunmy Post once 804 raco, so<wy.ca4sy. rennessa 37379 i
October 26,19954 i
U.S. Nuclear' Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Gentlemen:
In the Matter of
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Docket Nos. 50-327 Tennessee Valley Authority
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50 328 SEQUOYAH NUCLEAR PLANT (SON)- AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) SECTION XI RELIEF REQUEST SNUBBERS Enclosed is a request for relief from the requirements of ASME Section XI Code to exempt applicable snubbers and as an attornative, perform snubber examinations and testing in accordance with technical specifications (TSs). The proposed request for relief is applicable to SON's second ten year interval that is scheduled to begin on -
December 15,1995. SON is currently in the process of updating to the 1989 Edition of the ASME Code for its second ten year in-service inspection interval.
TVA has reviewed the snubber surveillance and functional test requirements contained in the ASME Code and SON's TSs. Based on this review, TVA concludes that these requirements would essentially be redundant and in some cases result in confusion created by differences in snubber categories. These differences can lead to misinterpretation when selecting test samples, applying acceptance criteria, corrective action, and examination schedules for failed snubbers. SON TS 3/4.7.9," Snubbers,"
provides a level of quality and safety equal to or greater than the ASME Code.
Accordingly, pursuant to 10 CFR 50.55a(a)(3), TVA is requesting relief from the ASME Code requirements for snubbers.
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U.S. Nuclear ' Regulatory Commission.
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s October 26,1995 Please direct questions concerning this issus to D. V. Goodin at (423) 843 7734.
- Sincerely,-
Of R. H. Shell' 4
Manager 4
- SON Site Licensing Enclosure cc (Enclosure):-
Mr. D. E. LaBarge, Project Manager Nuclear Regulatory Commission
'One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 2739 NRC Resident inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy Daisy, Tennessee 37379 3624 Regional Administrator U.S. Nuclear Regulatory Commission Region 11 101 Marietta Street, NW, Suite 2900 I
Atlanta, Georgia 30323 2711 i.
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7-SNUBBER RELIEF REQUEST Comoonents:
American Society of Mechanical Engineers (ASME)Section XI Code Class 1,2, and 3 snubbers.
Code Reoulrements:
- ASME Boiler and Pressure Vessel Code,Section XI,1989 Edition, Subarticles, IWF 5200 and IWF 5300 require that examinations and testing be performed in
-accordance with the 1988 Addenda to ASME/ ANSI OM 1987, Part 4. These requirements provide the methodology and corrective actions for examining and functionally testing snubbers, in addition, IWA 6230 requires in service inspection (ISI) summary reports for snubbers to be filed with the regulatory authority, and IWA 2100 requires authorized nuclear in service inspector involvement for snubber examination and testing.
Relief Reouest:
To exempt the applicable snubbers from the 1989 Edition of ASME Section XI Code.
Alternate Examination and Test:
SON will perform examinaCon and testing of snubbors as required by Technica!
Specification (TS) 3/4.7.9, " Snubbers."
Basis for Relief Sequoyah Nuclear Plant (SON) is required to incorporate the 1989 Edition of ASME Section XI Code as the governing document for the second ten year ISIinterval.
These requiremonts contain snubber examination and testing methodologies that are nearly identical to the methodologies prescribed in the TS for examination and testing of snubbers. Having two nearly redundant sets of snubber requirements presents unnecessary confusion in sample selection, data collection, acceptance criteria, and corrective actions. These requirements willin some cases cause a duplication of test documentation. In other cases, additional confusion is created by the difference in snubber categories. Approximately half of the snubbers at SON are required to be tested by both TSs and ASME Soction XI. The other half are only required to be tested by TS requirements. Thereforo, sampling becomes very confusing since some snubbers may be applicable to both requirements and others to only one. For the same reason, acceptance criteria and corrective action become difficult to apply.
One area where the requirements do not closely resemble each other is the snubber examination schedules. Snubber examination currently performed under TS 3/4.7.9, has been amended in accordance with Generic Letter (GL) 90 09," Alternative Requirements for Snubber Visual Inspection Intervals and Corrective Actions." The purpose of the GL was to provide alternative guidance to snubber inspection schedules that were excessively restrictive. The alternative schedule was to alleviate t
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2-the expenditure of unnecessary resources and prevent radiological exposure associated with the over restrictive examination schedule. The implementation of ASME/ ANSI OM 1987, Part 4, would return the examination schedule for approximately half of the snubbers in the examination program to the frequency which existed prior to the publication of GL 90 09, effectively cancelling the relaxation 6
provided by GL 90 09.
Justification:
The current program, as defined by TS 3/4.7.9, provides for a level of quality and safety equal to or greater than that of the OM Code. The OM Code provides for f ailure mode grouping of snubbers that f ail visual examination, meaning only those snubbers identified as being in that group would require shortened examination intervals. Under the rxis*ing TS program, all snubbers in the population would be placed in a shor ened inspection interval. On this basis, the existing TS program is more conservative in corrective action than the OM Code requirements. The altemative examination criteria is based on GL 90 09. As described above, the differences can create confusion while selecting test samples, applying acceptance critoria, corrective action, and examination schedules for failed snubbers. This situation could increase the possibility of applying the wrong action, thus creating a nonconformance, an inoperability or even a violation of TSs.
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In order to eliminate any mismterpretation or confusion in administering similar requirements for snubbers that partially overlap, and to remove the possibility of applying contradicting requirements to the same snubber (s), TVA proposes to examine and test snubbers in accordance with SON TS 3/4.7.9. TS requirements for testing and examination of snubbers provide an equal or greater level of quality and safety than ASME Section XI Code.
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Conclusion:==
Based on the above justification,it is concluded that in service examination and testing of snubbers,in accordance with the 1988 Addenda to ASME/ ANSI OM 1987, i
Part 4, would result in hardship or unusual difficulty without a compensating increase
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In the level of quality and safety. SON's examination and testing of snubbers, in 1
accordanco with TS 3/4.7.9, will provide an acceptable level of quality and safety.
Therefore, pursuant to 10 CFR 50.55a(a)(3),it is requested that relief be granted.
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