ML20085N123
| ML20085N123 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 11/07/1991 |
| From: | Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 91-639, NUDOCS 9111140095 | |
| Download: ML20085N123 (5) | |
Text
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. VIRGINIA ELECTRIC AND POWER COhlPANY Ricilht0ND, VIRGINIA 23261 November 7, 1991 United States Nuclear Regulatory Commission Serial No.91-639 Attention: Document Control Desk NL&P/JDH:jm] R1 Washington, D.C. 20555 Docket No.
50 339 License No.
NPF 7
- Gentlemen:
VIRGINIA-ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNIT 2 INSERVICE INSPECTION PROGRAM-RELIEF REQUEST FROM ASME SECTION XI REQUlBEMENTS SAFETY INJECTION ACCUMULATOR VESSEL WELD EXAMINATION On October 31,1990 (Serial No. 90 652), we requested relief from certain safety injection accumulator vessel weld examinations. Based on subsequent discussions with the NRC staff, we have revised that relief request. The attached relief request supersedes our October 31,1990 submittal.
Pursuant to 10 CFR 50.55a(g)(5), relief is requested from certain code requirements of ASME Section XI,1974 Edition, Summer 1975 Addenda, associated with the safety injection accumulator tanks for North Anna Unit 2.
Consistent with our previous request, we have determined the subject Code requirements to be impractical to the extent discussed in the attachment. The first inservice inspection interval for North Anna Unit 2 ended December 14, 1990.
Based on the requirements of 10CFR50.55(g)(5)(iv), we request relief from the specified Code requirements by December 14,1991.
This request has been reviewed and approved by the Station Nuclear Safety and Operating Committee.
Should you have any questions or require add!tional information, please contact us.
tr ly yoh Ve W. L. St rt Senior Vice President - Nuclear Attachment
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9111140095 911107 j
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cc:
United Stak. ", clear Regulatory Commission Region ll 101 Mariotta Street, N.W.
Suito 2900 Atlarita, GA 30323 Mr. M. S. Lessor NRC Senior Resident inspector North Anna Power Station l-l l
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i Attachment NORTH ANNA UNIT 2 RELIEF REQUEST FROM ASME SECI'lON XI REQUIREMENTS SAFETY INJECTION ACCUMULATOR VESSEL WELD EXAMINATION t
i Pursuant to 10 CFR 50.55a(g)(5), relief is requested from certain code requirements of ASME Section XI,1974 Edition, Summer 1975 Addende, associated with the safety i
injection accumulator tanks (welds 1,2,3 and 4) for North Anna Unit 2. This relief is required for North Anna Unit 2 for the first inspection interval, which onded on
. December 14,1990. The basis for our request is provided below,
- l. Identification of Comoonents 2 SI TK 1 A 18 and 1C Safety injection Accumulator Tank Wolds y
Drawing No.
Weld Ra, VGB 21210 1,2,3,4 II. Imoractical Code Recairements The Code requires in IWC 2500, category C A and IWC 2600, item C1.1, that a volumetric exam l nation be performed on the circumferential butt wolds of a vessel.
The examination would cover at least 20% of each weld uniformly distributed among
_ three areas around the vessel circumistence. Those exams would be distributed as described in IWC 2411 over the four intervals (40 years).
'lli,13 ash for Relief The safety injection accumu!ator tanks (2 SI TK 1 A,1B and 10) are ASME Class 2 i
vessels, welds 1,2,3 and 4 (nhown in attached drawing) are required to be examined as previously describod. The condition of theco welds, however, provents full volumetric examination coverage (i.e. Code Case N 460 requires at least 90% of the.
required volume be examined). The wolds muct be prepared by grinding the surface smooth to ensure completa examination coverage. Additionally, access to_ weld 2 is extremely limited due to the vesse! skirt. Partial volumetric (UT) examinations have boon performed on 2 SI TK-1 A for welds 1,3 and 4 (0 degree 33%,45 degrees -
18% and 60 degrees 43% coverage). Wold 2 was not examl
.1 because of its.
access problem.
Completion of the original first interval requirements, requiring surface preparation and possibly new qualifieri procedures or techniques (weld. 2) must be considered unnecessary, considering the newer Code requirements. The Code of reference for
. North Anna Unit 2 for the second interval per 10 CFR 50.55a (g) (4) (ii)is the 198G Edition of ASME Section XI. This odition exempts this vessel type in paragraph IWO-l
1221(o) from volumotric or Surface examination. As such, no futuro examination is planned on theso components, and continued financial and radiological doso investments as a result of the first interval requirements are deemed impractical.
IV. AttornataProvisjgag As an alternativo,it is toquested that the first interval requirements to examino 2 SI TK-1 A,18 and 10 as required by Category C A,itom C1.1 be considorod comploto based upon the partial examinations of wolds 1,3 and 4 and the 10 year hydrostatic test.
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