ML20206G416
| ML20206G416 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 11/04/1988 |
| From: | NRC OFFICE OF SPECIAL PROJECTS |
| To: | |
| Shared Package | |
| ML20206G037 | List:
|
| References | |
| NUDOCS 8811220272 | |
| Download: ML20206G416 (2) | |
Text
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'l' UNITED STATES H
'e NUCLEAR REGULATORY COMMISSION j
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I SAFETY EtALUATION PEPORT BY THE OFFICE OF SPECIAL PR0'ECTS
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El'PLOYEE CONCERN ELEkEliT REPORT CO 10504 "CONDUli AS FELATED TO C0hSTRUCT10N" TENNESSEE VALLEY AUTHORITY l
SEQUOYAH NUCLEAR POWER PLANTS UNITS 1 & 2 l
DOCKET h05. 50-327 AND 50-328 f
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Subject Categcry:
Construction (10000)
Sub ct.tegory :
Deterioration of Pertunent Facilities (10500)
Elerent:
ConduitasRelatedtoConstruction(10504)
Erployee Concern:
00-85-005-010 t
I The basis for Element Report C010504-SQN, Rev. 2, dated October 9, 1986, f
is Sequoyah Erployee Concern 00-55-005-010 which states:
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'Sequoyah: Exposed threads on all-thread 3-4 inch diameter conduit are rustirg.
This occurred where short nipples of all-thread
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j conduit Join fittings 12 to 30 ir.ches below ceiling penetrations, above the 710 ft, elevation, south part of auxiliary building.
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Condition existed at least until 1977, and may still exist.
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Construction Department concern. CI has no further information. No L
follow up required,"
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l This concern was evaluated by T) A as potentially nuclear safety-related.
i II. Sumary of issue The problen as defined by TVA is that threaded connections / fittings for electrical concuit are rusting and not being corrected. Therefore, this i
could adversely affect the plant, i
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j G911220272 881104 i
PDR AD3CK 03000327 P
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2 III. Evaluation TVA conducted visual inspections of installed conduit in the auxiliary building and held discussiens with knowledgeable electrical personnel fron rainten;nce and modification groups to determine if rust on threaded ccnduit conr.ections was a problen at Sequoyah.
In addition. TVA reviewed the following procedures to determine if requirements exitted to id66tify and proh1 Lit rust on conduit.
Standard Practice, SQA66 Plant Housekeeping, Rev. 9 Standeed Practice SQM2, Maintenance Management System, Rev.18 Modifications anc Additions Instruction, MAI-6, Rev. 6 The walkdcan inspection of the auxiliary bulloing, turbine building anc certain yard areas revealed only rinor surface rust on threaded conduit connecticr.s/fittirgs. The deterioration due to rust would not require any corrective action.
The majority of conduit in the turbine and yarc areas is aluminum, waereas in the auxiliary building the conduit is primarily galvanized which prohibit rust but I
is not rust resistant.
The discussions with electri:al personnel did r.ct reveal a problem with rust on conduits in the plants.
The review of the aforementiered procedures revealed that nousekeeping checklist contained itens to assist in identificetion of rus+. on con <uit; that any plant personnel may initiate a maintenance request for repair due to excess rust; and that redifications or additions done af ter February 1986 require threader conduit joint be rade watertight and rustproof by use of a thread compound (YOPR-SHIELD) which will not insulete the joint.
IV. Conclusion l
l The concern for rust on threaded cerduit connections / fittings has very minor safety sigrificance. Therefore, the hRC staff concludes that TVA's investigation and resolutien of the concern described in Element l
Report (010504 was adequate.
The NRC staff also concluded that no l
furtter action is required by hRC.
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