ML20087D319

Potential Part 21 Rept Re Problems W/Elmwood/Fasco Contactor Carriers Breaking in Contactor Model 30-FO-30. Caused by Distortion/Shrinkage of Molded Phenolic Contactor Carrier.Replacement Contactors Installed

ML20087D319
Person / Time
Site:	Vogtle
Issue date:	01/14/1992
From:	Patterson L NUTHERM INTERNATIONAL, INC.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
REF-PT21-92 QA-1-92-618, NUDOCS 9201160083
Download: ML20087D319 (2)

Text

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Nutherm&

NTERNATKWAL.AC

$01 SOLITH ELEVENTH STREET /MT. VERNON, ILLINDIS 62864'(618) 244 6000' FAX (618) 244-6641 January 14, 1992 OA 92- 618 Docment Conttol Desk United States Nuclear Regulatory Cannission Washington, DC 20555

Subject:

potential Deviation of Design Safety ,anction Elm ood/Fasco Contactors.

Nuthern, international Inc. , was inf orned on 10/2/91 by Georgia power Cmpany (GpC) plant Vogtle that they were experiencing problans with Elmood/Pasco contacter carriers breaking in contactor nodel# 30-FO-30 (now Fasco Model # 3M40-B) in their Engineered Safety Feature Heater Control panels (1/2-1531-N7-001/002-1101; 1/2-1561-N7-001/002-IIO1; and 7.-1542-N7-001/002-H01), nnufactured by Nutherm. Gpc has identified the primry root cause as distoraon/ shrinkage of the nolded phenolic contactor carrier such that the dengned clear # see fit with the laminated steel armature becmes an interference fit ultimtely resulting in f racture of the phenolic part due to induced tensiJe str~a. Subsequent testing by Nutherm has revealed that shrinkage of the contactor marriers does occur as a function of tine and tenverature. Further testing by sutherm is required to determine the maxinun shrinkage of the contactor carrier and to identify the extent of design changes required by the contactor nanuf acturer (Fasco).

Nutherm will respond within the required time f rane as identified in paragraph 21.21 of 10CFR F trt 21, dated July 31, 1991. In the interim GpC has installed replacment cont actors Fssco Hodel No. 3H40B, which my also require replacment when the inves'igation of the carrier problem has been concluded. These replacements flom Fasco were telected by Nutherm as those manuf actured to t he highest mnufacturer design range for clearance / tolerances for contact carriers.

Nuthetm at the wanuf acturer of the heaters and associated control panels has notified its custmer, Toerican Air Filter of Louisville, Kentucky, who is the original equipren', supplier to GpC of the potential problan.

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~ Doctnent Cantrol Desk l usmc j January 14, 1992 '

Page 2 of 2 If you should have any questions regarding this trntter please contact ne at (618) 244-6000 Sincerely,  ;

NUTHERM INTDsNATICXtAL, INC.

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Laurence Patterson Manager Quality Assurance LDP:lt PL:1115  ;

cc: GPC Al Odetto, Fasco  :

Kevin Young, Fasco Fax: Nancy Canpbel1, USNRC 4 1

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